Issue published July 2, 2018 Previous issue | Next issue
- Volume 128, Issue 7
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On the cover: Hematopoietic progenitors and endothelial cells evoke asthmatic angiogenesis
In this issue of the JCI, Asosingh et al. establish a central role for allergen-sensing hematopoietic progenitors and endothelial cells in the pathogenesis of asthma, reporting that the allergen-stimulated cells are sufficient to induce angiogenic remodeling, inflammation, and airway hyperreactivity in the lung endothelium. The cover image visualizes disruption of the murine airway endothelial barrier following exposure to house dust mite allergen. Dark-stained areas indicate where the endothelial barrier is breached by protease allergens.
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Review Series
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Abstract
Countless times each day, the acute inflammatory response protects us from invading microbes, injuries, and insults from within, as in surgery-induced tissue injury. These challenges go unnoticed because they are self-limited and naturally resolve without progressing to chronic inflammation. Peripheral blood markers of inflammation are present in many common diseases, including inflammatory bowel disease, cardiovascular disease, neurodegenerative disease, and cancer. While acute inflammation is protective, excessive swarming of neutrophils amplifies collateral tissue damage and inflammation. Hence, understanding the mechanisms that control the resolution of acute inflammation provides insight into preventing and treating inflammatory diseases in multiple organs. This Review focuses on the resolution phase of inflammation with identification of specialized pro-resolving mediators (SPMs) that involve three separate biosynthetic and potent mediator families, which are defined using the first quantitative resolution indices to score this vital process. These are the resolvins, protectins, and maresins: bioactive metabolomes that each stimulate self-limited innate responses, enhance innate microbial killing and clearance, and are organ-protective. We briefly address biosynthesis of SPMs and their activation of endogenous resolution programs as terrain for new therapeutic approaches that are not, by definition, immunosuppressive, but rather new immunoresolvent therapies.
Authors
Charles N. Serhan, Bruce D. Levy
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Phospholipids comprise a large body of lipids that define cells and organelles by forming membrane structures. Importantly, their complex metabolism represents a highly controlled cellular signaling network that is essential for mounting an effective innate immune response. Phospholipids in innate cells are subject to dynamic regulation by enzymes, whose activities are highly responsive to activation status. Along with their metabolic products, they regulate multiple aspects of innate immune cell biology, including shape change, aggregation, blood clotting, and degranulation. Phospholipid hydrolysis provides substrates for cell-cell communication, enables regulation of hemostasis, immunity, thrombosis, and vascular inflammation, and is centrally important in cardiovascular disease and associated comorbidities. Phospholipids themselves are also recognized by innate-like T cells, which are considered essential for recognition of infection or cancer, as well as self-antigens. This Review describes the major phospholipid metabolic pathways present in innate immune cells and summarizes the formation and metabolism of phospholipids as well as their emerging roles in cell biology and disease.
Authors
Valerie B. O’Donnell, Jamie Rossjohn, Michael J.O. Wakelam
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Leukotrienes are powerful immune-regulating lipid mediators with established pathogenic roles in inflammatory allergic diseases of the respiratory tract — in particular, asthma and hay fever. More recent work indicates that these lipids also contribute to low-grade inflammation, a hallmark of cardiovascular, neurodegenerative, and metabolic diseases as well as cancer. Biosynthesis of leukotrienes involves oxidative metabolism of arachidonic acid and proceeds via a set of soluble and membrane enzymes that are primarily expressed by cells of myeloid origin. In activated immune cells, these enzymes assemble at the endoplasmic and perinuclear membrane, constituting a biosynthetic complex. This Review describes recent advances in our understanding of the components of the leukotriene-synthesizing enzyme machinery, emerging opportunities for pharmacological intervention, and the development of new medicines exploiting both antiinflammatory and pro-resolving mechanisms.
Authors
Jesper Z. Haeggström
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Leukotrienes, a class of arachidonic acid–derived bioactive molecules, are known as mediators of allergic and inflammatory reactions and considered to be important drug targets. Although an inhibitor of leukotriene biosynthesis and antagonists of the cysteinyl leukotriene receptor are clinically used for bronchial asthma and allergic rhinitis, these medications were developed before the molecular identification of leukotriene receptors. Numerous studies using cloned leukotriene receptors and genetically engineered mice have unveiled new pathophysiological roles for leukotrienes. This Review covers the recent findings on leukotriene receptors to revisit them as new drug targets.
Authors
Takehiko Yokomizo, Motonao Nakamura, Takao Shimizu
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Aging is defined as the progressive deterioration of physiological function with age. Incidence of many pathologies increases with age, including neurological and cardiovascular diseases and cancer. Aging tissues become less adaptable and renewable, and cells undergo senescence, a process by which they “irreversibly” stop dividing. Senescence has been shown to serve as a tumor suppression mechanism with clear desirable effects. However, senescence also has deleterious consequences, especially for cardiovascular, metabolic, and immune systems. Sphingolipids are a major class of lipids that regulate cell biology, owing to their structural and bioactive properties and diversity. Their involvement in the regulation of aging and senescence has been demonstrated and studied in multiple organisms and cell types, especially that of ceramide and sphingosine-1-phosphate; ceramide induces cellular senescence and sphingosine-1–phosphate delays it. These discoveries could be very useful in the future to understand aging mechanisms and improve therapeutic interventions.
Authors
Magali Trayssac, Yusuf A. Hannun, Lina M. Obeid
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Non-resolving inflammation drives the development of clinically dangerous atherosclerotic lesions by promoting sustained plaque inflammation, large necrotic cores, thin fibrous caps, and thrombosis. Resolution of inflammation is not merely a passive return to homeostasis, but rather an active process mediated by specific molecules, including fatty acid–derived specialized pro-resolving mediators (SPMs). In advanced atherosclerosis, there is an imbalance between levels of SPMs and proinflammatory lipid mediators, which results in sustained leukocyte influx into lesions, inflammatory macrophage polarization, and impaired efferocytosis. In animal models of advanced atherosclerosis, restoration of SPMs limits plaque progression by suppressing inflammation, enhancing efferocytosis, and promoting an increase in collagen cap thickness. This Review discusses the roles of non-resolving inflammation in atherosclerosis and highlights the unique therapeutic potential of SPMs in blocking the progression of clinically dangerous plaques.
Authors
Canan Kasikara, Amanda C. Doran, Bishuang Cai, Ira Tabas
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Chronic inflammation is an underlying feature of many diseases, including chronic obstructive pulmonary disease, rheumatoid arthritis, asthma, and multiple sclerosis. There is an increasing appreciation of the dysregulation of adaptive immunity in chronic inflammatory and allergic diseases. The discovery of specialized pro-resolving lipid mediators (SPMs) that actively promote the resolution of inflammation has opened new avenues for the treatment of chronic inflammatory diseases. Much work has been done focusing on the impact of SPMs on innate immune cells. However, much less is known about the influence of SPMs on the development of antigen-specific adaptive immune responses. This Review highlights the important breakthroughs concerning the effects of SPMs on the key cell types involved in the development of adaptive immunity, namely dendritic cells, T cells, and B cells.
Authors
Parker F. Duffney, Megan L. Falsetta, Ashley R. Rackow, Thomas H. Thatcher, Richard P. Phipps, Patricia J. Sime
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Chronic inflammation is a risk factor for gastrointestinal cancer and other diseases. Most studies have focused on cytokines and chemokines as mediators connecting chronic inflammation to cancer, whereas the involvement of lipid mediators, including prostanoids, has not been extensively investigated. Prostanoids are among the earliest signaling molecules released in response to inflammation. Multiple lines of evidence suggest that prostanoids are involved in gastrointestinal cancer. In this Review, we discuss how prostanoids impact gastrointestinal cancer development. In particular, we highlight recent advances in our understanding of how prostaglandin E2 induces the immunosuppressive microenvironment in gastrointestinal cancers.
Authors
Dingzhi Wang, Raymond N. DuBois
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Commentaries
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Abstract
There is marked variability in vaccine efficacy among global populations. In particular, individuals in low- to middle-income countries have been shown to be less responsive to vaccines than those from developed nations. Several factors, including endemic infections, nutrition, genetics, and gut microbiome composition, have been proposed to underlie discrepancies in vaccine response. In this issue of the JCI, Kityo et al. evaluated response to yellow fever virus vaccine, inflammation, and lymphatic tissue architecture and fibrosis in three cohorts: two from the U.S. and one from Uganda. Compared with the U.S. subjects, the Ugandan cohort exhibited enhanced cytokine responses, increased lymph node fibrosis, reduced CD4+ T cell levels, and reduced vaccine response. Together, these results provide a link among chronic inflammation, damaged lymphoid architecture, and poor vaccine outcome, and set the stage for future studies to identify strategies to overcome these barriers.
Authors
Boris Julg, Galit Alter
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The discovery of HLA-B*57:01–associated abacavir hypersensitivity is a translational success story that eliminated adverse reactions to abacavir through pretreatment screening and defined a mechanistic model of an altered peptide repertoire. In this issue of the JCI, Cardone et al. have developed an HLA-B*57:01–transgenic mouse model and demonstrated that CD4+ T cells play a key role in mediating tolerance to the dramatically altered endogenous peptide repertoire induced by abacavir and postulate a known mechanism by which CD4+ T cells suppress DC maturation. This report potentially explains why 45% of HLA-B*57:01 carriers tolerate abacavir and provides a framework for future studies of HLA-restricted, T cell–mediated drug tolerance and hypersensitivity.
Authors
Elizabeth J. Phillips, Simon A. Mallal
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Stromal cells within the tumor microenvironment play a supportive role in tumor growth, progression, and treatment resistance; therefore, these nonmalignant cells are potential therapeutic targets. In this issue of the JCI, Szot et al. devised a strategy to exploit the cell-surface marker TEM8 (also known as ANTXR1), which is expressed by cancer-associated stromal cells, as a zip code to deliver an antibody-drug conjugate (ADC) linked to the potent cancer-killing drug monomethyl auristatin E (MMAE). In preclinical tumor and experimental metastasis models of multiple cancer types, TEM8-ADC targeted TEM8-expressing cancer-associated stromal cells, which processed and liberated membrane-permeable MMAE and released this drug via the P-glycoprotein (P-gp) drug transporter. Released MMAE killed cancer cells through a bystander mechanism that did minimal damage to the stromal cells themselves. P-gp–expressing tumor cells displayed MMAE resistance, suggesting that P-gp expression status may identify patients who might benefit the most from TEM8-ADC. This strategy, termed DAaRTS (drug activation and release through stroma), represents an elegant example of how selective expression of a cell-surface molecule on cancer-associated stroma can be exploited to facilitate drug delivery and shrink solid tumors.
Authors
James V. McCann, Jamie L. Null, Andrew C. Dudley
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Acute kidney injury comprises a heterogeneous group of conditions characterized by a sudden decrease in renal function over hours to days. Contrast-induced acute kidney injury (CI-AKI) is caused by radiographic contrast agents used in diagnostic imaging. In the current issue of the JCI, Lau et al. use a mouse model of CI-AKI to study the role of resident and infiltrating phagocytes, recruited leukocytes, and tubular cells in the immune surveillance response to contrast agents. This study has the potential to provide innovative therapies for human CI-AKI.
Authors
Simon J. Atkinson
×Abstract
The ability to recognize and avoid noxious stimuli is essential for survival. The factors that determine whether a given stimulus is considered positive or negative are complex and not fully understood. In this issue of the JCI, Klawonn and colleagues demonstrate that melanocortin 4 receptor (MC4R) signaling is critical for proper responses to negative stimuli. Mice lacking MC4R were shown to have a surprising preference for aversive stimuli compared with WT animals. Moreover, the authors provide evidence that avoidance behaviors are mediated by hypothalamic POMC neurons signaling to striatal dopamine D1 receptor–expressing medium spiny neurons. Together, these results provide important insight into the regulation of responses to aversive stimuli.
Authors
Alexandra G. DiFeliceantonio, Paul J. Kenny
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Interferonopathies are a subset of autoinflammatory disorders with a prominent type I IFN gene signature. Treatment of these patients has been challenging, given the lack of response to common autoinflammatory therapeutics including IL-1 and TNF blockade. JAK inhibitors (Jakinibs) are a family of small-molecule inhibitors that target the JAK/STAT signaling pathway and have shown clinical efficacy, with FDA and European Medicines Agency (EMA) approval for arthritic and myeloproliferative syndromes. Sanchez and colleagues repurposed baricitinib to establish a significant role for JAK inhibition as a novel therapy for patients with interferonopathies, demonstrating the power of translational rare disease research with lifesaving effects.
Authors
Hal M. Hoffman, Lori Broderick
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Research Articles
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Abstract
Vaccine responses vary by geographic location. We have previously described how HIV-associated inflammation leads to fibrosis of secondary lymph nodes (LNs) and T cell depletion. We hypothesized that other infections may cause LN inflammation and fibrosis, in a process similar to that seen in HIV infection, which may lead to T cell depletion and affect vaccine responses. We studied LNs of individuals from Kampala, Uganda, before and after yellow fever vaccination (YFV) and found fibrosis in LNs that was similar to that seen in HIV infection. We found blunted antibody responses to YFV that correlated to the amount of LN fibrosis and loss of T cells, including T follicular helper cells. These data suggest that LN fibrosis is not limited to HIV infection and may be associated with impaired immunologic responses to vaccines. This may have an impact on vaccine development, especially for infectious diseases prevalent in the developing world.
Authors
Cissy Kityo, Krystelle Nganou Makamdop, Meghan Rothenberger, Jeffrey G. Chipman, Torfi Hoskuldsson, Gregory J. Beilman, Bartosz Grzywacz, Peter Mugyenyi, Francis Ssali, Rama S. Akondy, Jodi Anderson, Thomas E. Schmidt, Thomas Reimann, Samuel P. Callisto, Jordan Schoephoerster, Jared Schuster, Proscovia Muloma, Patrick Ssengendo, Eirini Moysi, Constantinos Petrovas, Ray Lanciotti, Lin Zhang, Maria T. Arévalo, Benigno Rodriguez, Ted M. Ross, Lydie Trautmann, Rafick-Pierre Sekaly, Michael M. Lederman, Richard A. Koup, Rafi Ahmed, Cavan Reilly, Daniel C. Douek, Timothy W. Schacker
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Activation of non-neuronal microglia is thought to play a causal role in spinal processing of neuropathic pain. To specifically investigate microglia-mediated effects in a model of neuropathic pain and overcome the methodological limitations of previous approaches exploring microglia function upon nerve injury, we selectively ablated resident microglia by intracerebroventricular ganciclovir infusion into male CD11b-HSVTK–transgenic mice, which was followed by a rapid, complete, and persistent (23 weeks) repopulation of the CNS by peripheral myeloid cells. In repopulated mice that underwent sciatic nerve injury, we observed a normal response to mechanical stimuli, but an absence of thermal hypersensitivity ipsilateral to the injured nerve. Furthermore, we found that neuronal expression of calcitonin gene–related peptide (CGRP), which is a marker of neurons essential for heat responses, was diminished in the dorsal horn of the spinal cord in repopulated mice. These findings identify distinct mechanisms for heat and mechanical hypersensitivity and highlight a crucial contribution of CNS myeloid cells in the facilitation of noxious heat.
Authors
Stefanie Kälin, Kelly R. Miller, Roland E. Kälin, Marina Jendrach, Christian Witzel, Frank L. Heppner
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PIM kinase family members play a crucial role in promoting cell survival and proliferation via phosphorylation of their target substrates. In this study, we investigated the role of the PIM kinases with respect to T cell responses in transplantation and tumor immunity. We found that the PIM-2 isoform negatively regulated T cell responses to alloantigen, in contrast to the PIM-1 and PIM-3 isoforms, which acted as positive regulators. T cells deficient in PIM-2 demonstrated increased T cell differentiation toward Th1 subset, proliferation, and migration to target organs after allogeneic bone marrow transplantation, resulting in dramatically accelerated graft-versus-host disease (GVHD) severity. Restoration of PIM-2 expression markedly attenuated the pathogenicity of PIM-2–deficient T cells to induce GVHD. On the other hand, mice deficient in PIM-2 readily rejected syngeneic tumor, which was primarily dependent on CD8+ T cells. Furthermore, silencing PIM-2 in polyclonal or antigen-specific CD8+ T cells substantially enhanced their antitumor response in adoptive T cell immunotherapy. We conclude that PIM-2 kinase plays a prominent role in suppressing T cell responses, and provide a strong rationale to target PIM-2 for cancer immunotherapy.
Authors
Anusara Daenthanasanmak, Yongxia Wu, Supinya Iamsawat, Hung D. Nguyen, David Bastian, MengMeng Zhang, M. Hanief Sofi, Shilpak Chatterjee, Elizabeth G. Hill, Shikhar Mehrotra, Andrew S. Kraft, Xue-Zhong Yu
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NOTCH1 is a prevalent signaling pathway in T cell acute lymphoblastic leukemia (T-ALL), but crucial NOTCH1 downstream signals and target genes contributing to T-ALL pathogenesis cannot be retrospectively analyzed in patients and thus remain ill defined. This information is clinically relevant, as initiating lesions that lead to cell transformation and leukemia-initiating cell (LIC) activity are promising therapeutic targets against the major hurdle of T-ALL relapse. Here, we describe the generation in vivo of a human T cell leukemia that recapitulates T-ALL in patients, which arises de novo in immunodeficient mice reconstituted with human hematopoietic progenitors ectopically expressing active NOTCH1. This T-ALL model allowed us to identify CD44 as a direct NOTCH1 transcriptional target and to recognize CD44 overexpression as an early hallmark of preleukemic cells that engraft the BM and finally develop a clonal transplantable T-ALL that infiltrates lymphoid organs and brain. Notably, CD44 is shown to support crucial BM niche interactions necessary for LIC activity of human T-ALL xenografts and disease progression, highlighting the importance of the NOTCH1/CD44 axis in T-ALL pathogenesis. The observed therapeutic benefit of anti-CD44 antibody administration in xenotransplanted mice holds great promise for therapeutic purposes against T-ALL relapse.
Authors
Marina García-Peydró, Patricia Fuentes, Marta Mosquera, María J. García-León, Juan Alcain, Antonio Rodríguez, Purificación García de Miguel, Pablo Menéndez, Kees Weijer, Hergen Spits, David T. Scadden, Carlos Cuesta-Mateos, Cecilia Muñoz-Calleja, Francisco Sánchez-Madrid, María L. Toribio
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Adverse drug reactions (ADRs) are a major obstacle to drug development, and some of these, including hypersensitivity reactions to the HIV reverse transcriptase inhibitor abacavir (ABC), are associated with HLA alleles, particularly HLA-B*57:01. However, not all HLA-B*57:01+ patients develop ADRs, suggesting that in addition to the HLA genetic risk, other factors may influence the outcome of the response to the drug. To study HLA-linked ADRs in vivo, we generated HLA-B*57:01–Tg mice and show that, although ABC activated Tg mouse CD8+ T cells in vitro in a HLA-B*57:01–dependent manner, the drug was tolerated in vivo. In immunocompetent Tg animals, ABC induced CD8+ T cells with an anergy-like phenotype that did not lead to ADRs. In contrast, in vivo depletion of CD4+ T cells prior to ABC administration enhanced DC maturation to induce systemic ABC-reactive CD8+ T cells with an effector-like and skin-homing phenotype along with CD8+ infiltration and inflammation in drug-sensitized skin. B7 costimulatory molecule blockade prevented CD8+ T cell activation. These Tg mice provide a model for ABC tolerance and for the generation of HLA-B*57:01–restricted, ABC-reactive CD8+ T cells dependent on both HLA genetic risk and immunoregulatory host factors.
Authors
Marco Cardone, Karla Garcia, Mulualem E. Tilahun, Lisa F. Boyd, Sintayehu Gebreyohannes, Masahide Yano, Gregory Roderiquez, Adovi D. Akue, Leslie Juengst, Elliot Mattson, Suryatheja Ananthula, Kannan Natarajan, Montserrat Puig, David H. Margulies, Michael A. Norcross
×Abstract
Ischemia-reperfusion injury, a form of sterile inflammation, is the leading risk factor for both short-term mortality following pulmonary transplantation and chronic lung allograft dysfunction. While it is well recognized that neutrophils are critical mediators of acute lung injury, processes that guide their entry into pulmonary tissue are not well understood. Here, we found that CCR2+ classical monocytes are necessary and sufficient for mediating extravasation of neutrophils into pulmonary tissue during ischemia-reperfusion injury following hilar clamping or lung transplantation. The classical monocytes were mobilized from the host spleen, and splenectomy attenuated the recruitment of classical monocytes as well as the entry of neutrophils into injured lung tissue, which was associated with improved graft function. Neutrophil extravasation was mediated by MyD88-dependent IL-1β production by graft-infiltrating classical monocytes, which downregulated the expression of the tight junction–associated protein ZO-2 in pulmonary vascular endothelial cells. Thus, we have uncovered a crucial role for classical monocytes, mobilized from the spleen, in mediating neutrophil extravasation, with potential implications for targeting of recipient classical monocytes to ameliorate pulmonary ischemia-reperfusion injury in the clinic.
Authors
Hsi-Min Hsiao, Ramiro Fernandez, Satona Tanaka, Wenjun Li, Jessica H. Spahn, Stephen Chiu, Mahzad Akbarpour, Daniel Ruiz-Perez, Qiang Wu, Cem Turam, Davide Scozzi, Tsuyoshi Takahashi, Hannah P. Luehmann, Varun Puri, G.R. Scott Budinger, Alexander S. Krupnick, Alexander V. Misharin, Kory J. Lavine, Yongjian Liu, Andrew E. Gelman, Ankit Bharat, Daniel Kreisel
×Abstract
Neurofibromatosis type 1 associates with multiple neoplasms, and the Schwann cell tumor neurofibroma is the most prevalent. A hallmark feature of neurofibroma is mast cell infiltration, which is recruited by chemoattractant stem cell factor (SCF) and has been suggested to sustain neurofibroma tumorigenesis. In the present study, we use new, genetically engineered Scf mice to decipher the contributions of tumor-derived SCF and mast cells to neurofibroma development. We demonstrate that mast cell infiltration is dependent on SCF from tumor Schwann cells. However, removal of mast cells by depleting the main SCF source only slightly affects neurofibroma progression. Other inflammation signatures show that all neurofibromas are associated with high levels of macrophages regardless of Scf status. These findings suggest an active inflammation in neurofibromas and partly explain why mast cell removal alone is not sufficient to relieve tumor burden in this experimental neurofibroma model. Furthermore, we show that plexiform neurofibromas are highly associated with injury-prone spinal nerves that are close to flexible vertebras. In summary, our study details the role of inflammation in neurofibromagenesis. Our data indicate that prevention of inflammation and possibly also nerve injury at the observed tumor locations are therapeutic approaches for neurofibroma prophylaxis and that such treatment should be explored.
Authors
Chung-Ping Liao, Reid C. Booker, Jean-Philippe Brosseau, Zhiguo Chen, Juan Mo, Edem Tchegnon, Yong Wang, D. Wade Clapp, Lu Q. Le
×Abstract
The human brain is an important site of HIV replication and persistence during antiretroviral therapy (ART). Direct evaluation of HIV infection in the brains of otherwise healthy individuals is not feasible; therefore, we performed a large-scale study of bone marrow/liver/thymus (BLT) humanized mice as an in vivo model to study HIV infection in the brain. Human immune cells, including CD4+ T cells and macrophages, were present throughout the BLT mouse brain. HIV DNA, HIV RNA, and/or p24+ cells were observed in the brains of HIV-infected animals, regardless of the HIV isolate used. HIV infection resulted in decreased numbers of CD4+ T cells, increased numbers of CD8+ T cells, and a decreased CD4+/CD8+ T cell ratio in the brain. Using humanized T cell–only mice (ToM), we demonstrated that T cells establish and maintain HIV infection of the brain in the complete absence of human myeloid cells. HIV infection of ToM resulted in CD4+ T cell depletion and a reduced CD4+/CD8+ T cell ratio. ART significantly reduced HIV levels in the BLT mouse brain, and the immune cell populations present were indistinguishable from those of uninfected controls, which demonstrated the effectiveness of ART in controlling HIV replication in the CNS and returning cellular homeostasis to a pre-HIV state.
Authors
Jenna B. Honeycutt, Baolin Liao, Christopher C. Nixon, Rachel A. Cleary, William O. Thayer, Shayla L. Birath, Michael D. Swanson, Patricia Sheridan, Oksana Zakharova, Francesca Prince, JoAnn Kuruc, Cynthia L. Gay, Chris Evans, Joseph J. Eron, Angela Wahl, J. Victor Garcia
×Abstract
Drug resistance remains the key problem in cancer treatment. It is now accepted that each myeloma patient harbors multiple subclones and subclone dominance may change over time. The coexistence of multiple subclones with high or low chromosomal instability (CIN) signature causes heterogeneity and drug resistance with consequent disease relapse. In this study, using a tandem affinity purification–mass spectrometry (TAP-MS) technique, we found that NEK2, a CIN gene, was bound to the deubiquitinase USP7. Binding to USP7 prevented NEK2 ubiquitination resulting in NEK2 stabilization. Increased NEK2 kinase levels activated the canonical NF-κB signaling pathway through the PP1α/AKT axis. Newly diagnosed myeloma patients with activated NF-κB signaling through increased NEK2 activity had poorer event-free and overall survivals based on multiple independent clinical cohorts. We also found that NEK2 activated heparanase, a secreted enzyme, responsible for bone destruction in an NF-κB–dependent manner. Intriguingly, both NEK2 and USP7 inhibitors showed great efficacy in inhibiting myeloma cell growth and overcoming NEK2-induced and -acquired drug resistance in xenograft myeloma mouse models.
Authors
Reinaldo Franqui-Machin, Mu Hao, Hua Bai, Zhimin Gu, Xin Zhan, Hasem Habelhah, Yogesh Jethava, Lugui Qiu, Ivana Frech, Guido Tricot, Fenghuang Zhan
×Abstract
Radiographic contrast agents cause acute kidney injury (AKI), yet the underlying pathogenesis is poorly understood. Nod-like receptor pyrin containing 3–deficient (Nlrp3-deficient) mice displayed reduced epithelial cell injury and inflammation in the kidney in a model of contrast-induced AKI (CI-AKI). Unexpectedly, contrast agents directly induced tubular epithelial cell death in vitro that was not dependent on Nlrp3. Rather, contrast agents activated the canonical Nlrp3 inflammasome in macrophages. Intravital microscopy revealed diatrizoate (DTA) uptake within minutes in perivascular CX3CR1+ resident phagocytes in the kidney. Following rapid filtration into the tubular luminal space, DTA was reabsorbed and concentrated in tubular epithelial cells via the brush border enzyme dipeptidase-1 in volume-depleted but not euvolemic mice. LysM-GFP+ macrophages recruited to the kidney interstitial space ingested contrast material transported from the urine via direct interactions with tubules. CI-AKI was dependent on resident renal phagocytes, IL-1, leukocyte recruitment, and dipeptidase-1. Levels of the inflammasome-related urinary biomarkers IL-18 and caspase-1 were increased immediately following contrast administration in patients undergoing coronary angiography, consistent with the acute renal effects observed in mice. Taken together, these data show that CI-AKI is a multistep process that involves immune surveillance by resident and infiltrating renal phagocytes, Nlrp3-dependent inflammation, and the tubular reabsorption of contrast via dipeptidase-1.
Authors
Arthur Lau, Hyunjae Chung, Takanori Komada, Jaye M. Platnich, Christina F. Sandall, Saurav Roy Choudhury, Justin Chun, Victor Naumenko, Bas G.J. Surewaard, Michelle C. Nelson, Annegret Ulke-Lemée, Paul L. Beck, Hallgrimur Benediktsson, Anthony M. Jevnikar, Sarah L. Snelgrove, Michael J. Hickey, Donna L. Senger, Matthew T. James, Justin A. Macdonald, Paul Kubes, Craig N. Jenne, Daniel A. Muruve
×Abstract
Complications of diabetes affect tissues throughout the body, including the central nervous system. Epidemiological studies show that diabetic patients have an increased risk of depression, anxiety, age-related cognitive decline, and Alzheimer’s disease. Mice lacking insulin receptor (IR) in the brain or on hypothalamic neurons display an array of metabolic abnormalities; however, the role of insulin action on astrocytes and neurobehaviors remains less well studied. Here, we demonstrate that astrocytes are a direct insulin target in the brain and that knockout of IR on astrocytes causes increased anxiety- and depressive-like behaviors in mice. This can be reproduced in part by deletion of IR on astrocytes in the nucleus accumbens. At a molecular level, loss of insulin signaling in astrocytes impaired tyrosine phosphorylation of Munc18c. This led to decreased exocytosis of ATP from astrocytes, resulting in decreased purinergic signaling on dopaminergic neurons. These reductions contributed to decreased dopamine release from brain slices. Central administration of ATP analogs could reverse depressive-like behaviors in mice with astrocyte IR knockout. Thus, astrocytic insulin signaling plays an important role in dopaminergic signaling, providing a potential mechanism by which astrocytic insulin action may contribute to increased rates of depression in people with diabetes, obesity, and other insulin-resistant states.
Authors
Weikang Cai, Chang Xue, Masaji Sakaguchi, Masahiro Konishi, Alireza Shirazian, Heather A. Ferris, Mengyao E. Li, Ruichao Yu, Andre Kleinridders, Emmanuel N. Pothos, C. Ronald Kahn
×Abstract
Although nonmalignant stromal cells facilitate tumor growth and can occupy up to 90% of a solid tumor mass, better strategies to exploit these cells for improved cancer therapy are needed. Here, we describe a potent MMAE-linked antibody-drug conjugate (ADC) targeting tumor endothelial marker 8 (TEM8, also known as ANTXR1), a highly conserved transmembrane receptor broadly overexpressed on cancer-associated fibroblasts, endothelium, and pericytes. Anti-TEM8 ADC elicited potent anticancer activity through an unexpected killing mechanism we term DAaRTS (drug activation and release through stroma), whereby the tumor microenvironment localizes active drug at the tumor site. Following capture of ADC prodrug from the circulation, tumor-associated stromal cells release active MMAE free drug, killing nearby proliferating tumor cells in a target-independent manner. In preclinical studies, ADC treatment was well tolerated and induced regression and often eradication of multiple solid tumor types, blocked metastatic growth, and prolonged overall survival. By exploiting TEM8+ tumor stroma for targeted drug activation, these studies reveal a drug delivery strategy with potential to augment therapies against multiple cancer types.
Authors
Christopher Szot, Saurabh Saha, Xiaoyan M. Zhang, Zhongyu Zhu, Mary Beth Hilton, Karen Morris, Steven Seaman, James M. Dunleavey, Kuo-Sheng Hsu, Guo-Jun Yu, Holly Morris, Deborah A. Swing, Diana C. Haines, Yanping Wang, Jennifer Hwang, Yang Feng, Dean Welsch, Gary DeCrescenzo, Amit Chaudhary, Enrique Zudaire, Dimiter S. Dimitrov, Brad St. Croix
×Abstract
The transcription factor GATA6 has been shown to be important for lung development and branching morphogenesis in mouse models, but its role in human lung development is largely unknown. Here, we studied the role of GATA6 during lung differentiation using human pluripotent stem cells. We found that the human stem cell lines most efficient at generating NKX2.1+ lung progenitors express lower endogenous levels of GATA6 during endoderm patterning and that knockdown of GATA6 during endoderm patterning increased the generation of these cells. Complete ablation of GATA6 resulted in the generation of lung progenitors displaying increased cell proliferation with up to a 15-fold expansion compared with control cells, whereas the null cell line displayed a defect in further development into mature lung cell types. Furthermore, transgenic expression of GATA6 at the endoderm anteriorization stage skewed development toward a liver fate at the expense of lung progenitors. Our results suggest a critical dosage effect of GATA6 during human endoderm patterning and a later requirement during terminal lung differentiation. These studies offer an approach of modulating GATA6 expression to enhance the production of lung progenitors from human stem cell sources.
Authors
Chia-Min Liao, Somdutta Mukherjee, Amita Tiyaboonchai, Jean Ann Maguire, Fabian L. Cardenas-Diaz, Deborah L. French, Paul Gadue
×Abstract
A synthetic lethality–based strategy has been developed to identify therapeutic targets in cancer harboring tumor-suppressor gene mutations, as exemplified by the effectiveness of poly ADP-ribose polymerase (PARP) inhibitors in BRCA1/2-mutated tumors. However, many synthetic lethal interactors are less reliable due to the fact that such genes usually do not perform fundamental or indispensable functions in the cell. Here, we developed an approach to identifying the “essential lethality” arising from these mutated/deleted essential genes, which are largely tolerated in cancer cells due to genetic redundancy. We uncovered the cohesion subunit SA1 as a putative synthetic-essential target in cancers carrying inactivating mutations of its paralog, SA2. In SA2-deficient Ewing sarcoma and bladder cancer, further depletion of SA1 profoundly and specifically suppressed cancer cell proliferation, survival, and tumorigenic potential. Mechanistically, inhibition of SA1 in the SA2-mutated cells led to premature chromatid separation, dramatic extension of mitotic duration, and consequently, lethal failure of cell division. More importantly, depletion of SA1 rendered those SA2-mutated cells more susceptible to DNA damage, especially double-strand breaks (DSBs), due to reduced functionality of DNA repair. Furthermore, inhibition of SA1 sensitized the SA2-deficient cancer cells to PARP inhibitors in vitro and in vivo, providing a potential therapeutic strategy for patients with SA2-deficient tumors.
Authors
Yunhua Liu, Hanchen Xu, Kevin Van der Jeught, Yujing Li, Sheng Liu, Lu Zhang, Yuanzhang Fang, Xinna Zhang, Milan Radovich, Bryan P. Schneider, Xiaoming He, Cheng Huang, Chi Zhang, Jun Wan, Guang Ji, Xiongbin Lu
×Abstract
Toll-like receptors TLR7 and TLR9 are both implicated in the activation of autoreactive B cells and other cell types associated with systemic lupus erythematosus (SLE) pathogenesis. However, Tlr9–/– autoimmune-prone strains paradoxically develop more severe disease. We have now leveraged the negative regulatory role of TLR9 to develop an inducible rapid-onset murine model of systemic autoimmunity that depends on T cell detection of a membrane-bound OVA fusion protein expressed by MHC class II+ cells, expression of TLR7, expression of the type I IFN receptor, and loss of expression of TLR9. These mice are distinguished by a high frequency of OVA-specific Tbet+, IFN-γ+, and FasL-expressing Th1 cells as well as autoantibody-producing B cells. Unexpectedly, contrary to what occurs in most models of SLE, they also developed skin lesions that are very similar to those of human cutaneous lupus erythematosus (CLE) as far as clinical appearance, histological changes, and gene expression. FasL was a key effector mechanism in the skin, as the transfer of FasL-deficient DO11gld T cells completely failed to elicit overt skin lesions. FasL was also upregulated in human CLE biopsies. Overall, our model provides a relevant system for exploring the pathophysiology of CLE as well as the negative regulatory role of TLR9.
Authors
Purvi Mande, Bahar Zirak, Wei-Che Ko, Keyon Taravati, Karen L. Bride, Tia Y. Brodeur, April Deng, Karen Dresser, Zhaozhao Jiang, Rachel Ettinger, Katherine A. Fitzgerald, Michael D. Rosenblum, John E. Harris, Ann Marshak-Rothstein
×Abstract
Epigenetic modifications control cancer development and clonal evolution in various cancer types. Here, we show that loss of the male-specific histone demethylase lysine-specific demethylase 5D (KDM5D) encoded on the Y chromosome epigenetically modifies histone methylation marks and alters gene expression, resulting in aggressive prostate cancer. Fluorescent in situ hybridization demonstrated that segmental or total deletion of the Y chromosome in prostate cancer cells is one of the causes of decreased KDM5D mRNA expression. The result of ChIP-sequencing analysis revealed that KDM5D preferably binds to promoter regions with coenrichment of the motifs of crucial transcription factors that regulate the cell cycle. Loss of KDM5D expression with dysregulated H3K4me3 transcriptional marks was associated with acceleration of the cell cycle and mitotic entry, leading to increased DNA-replication stress. Analysis of multiple clinical data sets reproducibly showed that loss of expression of KDM5D confers a poorer prognosis. Notably, we also found stress-induced DNA damage on the serine/threonine protein kinase ATR with loss of KDM5D. In KDM5D-deficient cells, blocking ATR activity with an ATR inhibitor enhanced DNA damage, which led to subsequent apoptosis. These data start to elucidate the biological characteristics resulting from loss of KDM5D and also provide clues for a potential novel therapeutic approach for this subset of aggressive prostate cancer.
Authors
Kazumasa Komura, Yuki Yoshikawa, Teppei Shimamura, Goutam Chakraborty, Travis A. Gerke, Kunihiko Hinohara, Kalyani Chadalavada, Seong Ho Jeong, Joshua Armenia, Shin-Yi Du, Ying Z. Mazzu, Kohei Taniguchi, Naokazu Ibuki, Clifford A. Meyer, Gouri J. Nanjangud, Teruo Inamoto, Gwo-Shu Mary Lee, Lorelei A. Mucci, Haruhito Azuma, Christopher J. Sweeney, Philip W. Kantoff
×Abstract
Very few B cells in germinal centers (GCs) and extrafollicular (EF) regions of lymph nodes express CD30. Their specific features and relationship to CD30-expressing Hodgkin and Reed/Sternberg (HRS) cells of Hodgkin lymphoma are unclear but highly relevant, because numerous patients with lymphoma are currently treated with an anti-CD30 immunotoxin. We performed a comprehensive analysis of human CD30+ B cells. Phenotypic and IgV gene analyses indicated that CD30+ GC B lymphocytes represent typical GC B cells, and that CD30+ EF B cells are mostly post-GC B cells. The transcriptomes of CD30+ GC and EF B cells largely overlapped, sharing a strong MYC signature, but were strikingly different from conventional GC B cells and memory B and plasma cells, respectively. CD30+ GC B cells represent MYC+ centrocytes redifferentiating into centroblasts; CD30+ EF B cells represent active, proliferating memory B cells. HRS cells shared typical transcriptome patterns with CD30+ B cells, suggesting that they originate from these lymphocytes or acquire their characteristic features during lymphomagenesis. By comparing HRS to normal CD30+ B cells we redefined aberrant and disease-specific features of HRS cells. A remarkable downregulation of genes regulating genomic stability and cytokinesis in HRS cells may explain their genomic instability and multinuclearity.
Authors
Marc A. Weniger, Enrico Tiacci, Stefanie Schneider, Judith Arnolds, Sabrina Rüschenbaum, Janine Duppach, Marc Seifert, Claudia Döring, Martin-Leo Hansmann, Ralf Küppers
×Abstract
Spinal muscular atrophy (SMA), a degenerative motor neuron (MN) disease, caused by loss of functional survival of motor neuron (SMN) protein due to SMN1 gene mutations, is a leading cause of infant mortality. Increasing SMN levels ameliorates the disease phenotype and is unanimously accepted as a therapeutic approach for patients with SMA. The ubiquitin/proteasome system is known to regulate SMN protein levels; however, whether autophagy controls SMN levels remains poorly explored. Here, we show that SMN protein is degraded by autophagy. Pharmacological and genetic inhibition of autophagy increases SMN levels, while induction of autophagy decreases these levels. SMN degradation occurs via its interaction with the autophagy adapter p62 (also known as SQSTM1). We also show that SMA neurons display reduced autophagosome clearance, increased p62 and ubiquitinated proteins levels, and hyperactivated mTORC1 signaling. Importantly, reducing p62 levels markedly increases SMN and its binding partner gemin2, promotes MN survival, and extends lifespan in fly and mouse SMA models, revealing p62 as a potential new therapeutic target for the treatment of SMA.
Authors
Natalia Rodriguez-Muela, Andrey Parkhitko, Tobias Grass, Rebecca M. Gibbs, Erika M. Norabuena, Norbert Perrimon, Rajat Singh, Lee L. Rubin
×Abstract
Medial vascular calcification, associated with enhanced mortality in chronic kidney disease (CKD), is fostered by osteo-/chondrogenic transdifferentiation of vascular smooth muscle cells (VSMCs). Here, we describe that serum- and glucocorticoid-inducible kinase 1 (SGK1) was upregulated in VSMCs under calcifying conditions. In primary human aortic VSMCs, overexpression of constitutively active SGK1S422D, but not inactive SGK1K127N, upregulated osteo-/chondrogenic marker expression and activity, effects pointing to increased osteo-/chondrogenic transdifferentiation. SGK1S422D induced nuclear translocation and increased transcriptional activity of NF-κB. Silencing or pharmacological inhibition of IKK abrogated the osteoinductive effects of SGK1S422D. Genetic deficiency, silencing, and pharmacological inhibition of SGK1 dissipated phosphate-induced calcification and osteo-/chondrogenic transdifferentiation of VSMCs. Aortic calcification, stiffness, and osteo-/chondrogenic transdifferentiation in mice following cholecalciferol overload were strongly reduced by genetic knockout or pharmacological inhibition of Sgk1 by EMD638683. Similarly, Sgk1 deficiency blunted vascular calcification in apolipoprotein E–deficient mice after subtotal nephrectomy. Treatment of human aortic smooth muscle cells with serum from uremic patients induced osteo-/chondrogenic transdifferentiation, effects ameliorated by EMD638683. These observations identified SGK1 as a key regulator of vascular calcification. SGK1 promoted vascular calcification, at least partly, via NF-κB activation. Inhibition of SGK1 may, thus, reduce the burden of vascular calcification in CKD.
Authors
Jakob Voelkl, Trang T.D. Luong, Rashad Tuffaha, Katharina Musculus, Tilman Auer, Xiaoming Lian, Christoph Daniel, Daniel Zickler, Beate Boehme, Michael Sacherer, Bernhard Metzler, Dietmar Kuhl, Maik Gollasch, Kerstin Amann, Dominik N. Müller, Burkert Pieske, Florian Lang, Ioana Alesutan
×Abstract
BACKGROUND. Monogenic IFN–mediated autoinflammatory diseases present in infancy with systemic inflammation, an IFN response gene signature, inflammatory organ damage, and high mortality. We used the JAK inhibitor baricitinib, with IFN-blocking activity in vitro, to ameliorate disease. METHODS. Between October 2011 and February 2017, 10 patients with CANDLE (chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperatures), 4 patients with SAVI (stimulator of IFN genes–associated [STING-associated] vasculopathy with onset in infancy), and 4 patients with other interferonopathies were enrolled in an expanded access program. The patients underwent dose escalation, and the benefit was assessed by reductions in daily disease symptoms and corticosteroid requirement. Quality of life, organ inflammation, changes in IFN-induced biomarkers, and safety were longitudinally assessed. RESULTS. Eighteen patients were treated for a mean duration of 3.0 years (1.5–4.9 years). The median daily symptom score decreased from 1.3 (interquartile range [IQR], 0.93–1.78) to 0.25 (IQR, 0.1–0.63) (P < 0.0001). In 14 patients receiving corticosteroids at baseline, daily prednisone doses decreased from 0.44 mg/kg/day (IQR, 0.31–1.09) to 0.11 mg/kg/day (IQR, 0.02–0.24) (P < 0.01), and 5 of 10 patients with CANDLE achieved lasting clinical remission. The patients’ quality of life and height and bone mineral density Z-scores significantly improved, and their IFN biomarkers decreased. Three patients, two of whom had genetically undefined conditions, discontinued treatment because of lack of efficacy, and one CANDLE patient discontinued treatment because of BK viremia and azotemia. The most common adverse events were upper respiratory infections, gastroenteritis, and BK viruria and viremia. CONCLUSION. Upon baricitinib treatment, clinical manifestations and inflammatory and IFN biomarkers improved in patients with the monogenic interferonopathies CANDLE, SAVI, and other interferonopathies. Monitoring safety and efficacy is important in benefit-risk assessment. TRIAL REGISTRATION. ClinicalTrials.gov NCT01724580 and NCT02974595. FUNDING. This research was supported by the Intramural Research Program of the NIH, NIAID, and NIAMS. Baricitinib was provided by Eli Lilly and Company, which is the sponsor of the expanded access program for this drug.
Authors
Gina A. Montealegre Sanchez, Adam Reinhardt, Suzanne Ramsey, Helmut Wittkowski, Philip J. Hashkes, Yackov Berkun, Susanne Schalm, Sara Murias, Jason A. Dare, Diane Brown, Deborah L. Stone, Ling Gao, Thomas Klausmeier, Dirk Foell, Adriana A. de Jesus, Dawn C. Chapelle, Hanna Kim, Samantha Dill, Robert A. Colbert, Laura Failla, Bahar Kost, Michelle O’Brien, James C. Reynolds, Les R. Folio, Katherine R. Calvo, Scott M. Paul, Nargues Weir, Alessandra Brofferio, Ariane Soldatos, Angelique Biancotto, Edward W. Cowen, John J. Digiovanna, Massimo Gadina, Andrew J. Lipton, Colleen Hadigan, Steven M. Holland, Joseph Fontana, Ahmad S. Alawad, Rebecca J. Brown, Kristina I. Rother, Theo Heller, Kristina M. Brooks, Parag Kumar, Stephen R. Brooks, Meryl Waldman, Harsharan K. Singh, Volker Nickeleit, Maria Silk, Apurva Prakash, Jonathan M. Janes, Seza Ozen, Paul G. Wakim, Paul A. Brogan, William L. Macias, Raphaela Goldbach-Mansky
×Abstract
Progression of chronic kidney disease associated with progressive fibrosis and impaired tubular epithelial regeneration is still an unmet biomedical challenge because, once chronic lesions have manifested, no effective therapies are available as of yet for clinical use. Prompted by various studies across multiple organs demonstrating that preconditioning regimens to induce endogenous regenerative mechanisms protect various organs from later incurring acute injuries, we here aimed to gain insights into the molecular mechanisms underlying successful protection and to explore whether such pathways could be utilized to inhibit progression of chronic organ injury. We identified a protective mechanism controlled by the transcription factor ARNT that effectively inhibits progression of chronic kidney injury by transcriptional induction of ALK3, the principal mediator of antifibrotic and proregenerative bone morphogenetic protein–signaling (BMP-signaling) responses. We further report that ARNT expression itself is controlled by the FKBP12/YY1 transcriptional repressor complex and that disruption of such FKBP12/YY1 complexes by picomolar FK506 at subimmunosuppressive doses increases ARNT expression, subsequently leading to homodimeric ARNT-induced ALK3 transcription. Direct targeting of FKBP12/YY1 with in vivo morpholino approaches or small molecule inhibitors, including GPI-1046, was equally effective for inducing ARNT expression, with subsequent activation of ALK3-dependent canonical BMP-signaling responses and attenuated chronic organ failure in models of chronic kidney disease, and also cardiac and liver injuries. In summary, we report an organ-protective mechanism that can be pharmacologically modulated by immunophilin ligands FK506 and GPI-1046 or therapeutically targeted by in vivo morpholino approaches.
Authors
Björn Tampe, Désirée Tampe, Gunsmaa Nyamsuren, Friederike Klöpper, Gregor Rapp, Anne Kauffels, Thomas Lorf, Elisabeth M. Zeisberg, Gerhard A. Müller, Raghu Kalluri, Samy Hakroush, Michael Zeisberg
×Abstract
Ikaros/IKZF1 is an essential transcription factor expressed throughout hematopoiesis. IKZF1 is implicated in lymphocyte and myeloid differentiation and negative regulation of cell proliferation. In humans, somatic mutations in IKZF1 have been linked to the development of B cell acute lymphoblastic leukemia (ALL) in children and adults. Recently, heterozygous germline IKZF1 mutations have been identified in patients with a B cell immune deficiency mimicking common variable immunodeficiency. These mutations demonstrated incomplete penetrance and led to haploinsufficiency. Herein, we report 7 unrelated patients with a novel early-onset combined immunodeficiency associated with de novo germline IKZF1 heterozygous mutations affecting amino acid N159 located in the DNA-binding domain of IKZF1. Different bacterial and viral infections were diagnosed, but Pneumocystis jirovecii pneumonia was reported in all patients. One patient developed a T cell ALL. This immunodeficiency was characterized by innate and adaptive immune defects, including low numbers of B cells, neutrophils, eosinophils, and myeloid dendritic cells, as well as T cell and monocyte dysfunctions. Notably, most T cells exhibited a naive phenotype and were unable to evolve into effector memory cells. Functional studies indicated these mutations act as dominant negative. This defect expands the clinical spectrum of human IKZF1-associated diseases from somatic to germline, from haploinsufficient to dominant negative.
Authors
David Boutboul, Hye Sun Kuehn, Zoé Van de Wyngaert, Julie E. Niemela, Isabelle Callebaut, Jennifer Stoddard, Christelle Lenoir, Vincent Barlogis, Catherine Farnarier, Frédéric Vely, Nao Yoshida, Seiji Kojima, Hirokazu Kanegane, Akihiro Hoshino, Fabian Hauck, Ludovic Lhermitte, Vahid Asnafi, Philip Roehrs, Shaoying Chen, James W. Verbsky, Katherine R. Calvo, Ammar Husami, Kejian Zhang, Joseph Roberts, David Amrol, John Sleaseman, Amy P. Hsu, Steven M. Holland, Rebecca Marsh, Alain Fischer, Thomas A. Fleisher, Capucine Picard, Sylvain Latour, Sergio D. Rosenzweig
×Abstract
The superoxide-generating enzyme Nox2 contributes to hypertension and cardiovascular remodeling triggered by activation of the renin-angiotensin system. Multiple Nox2-expressing cells are implicated in angiotensin II–induced (Ang II–induced) pathophysiology, but the importance of Nox2 in leukocyte subsets is poorly understood. Here, we investigated the role of Nox2 in T cells, particularly Tregs. Mice globally deficient in Nox2 displayed increased numbers of Tregs in the heart at baseline, whereas Ang II–induced effector T cell (Teff) infiltration was inhibited. To investigate the role of Treg Nox2, we generated a mouse line with CD4-targeted Nox2 deficiency (Nox2fl/flCD4Cre+). These animals showed inhibition of Ang II–induced hypertension and cardiac remodeling related to increased tissue-resident Tregs and reduction in infiltrating Teffs, including Th17 cells. The protection in Nox2fl/flCD4Cre+ mice was reversed by anti-CD25 antibody depletion of Tregs. Mechanistically, Nox2–/y Tregs showed higher in vitro suppression of Teff proliferation than WT Tregs, increased nuclear levels of FoxP3 and NF-κB, and enhanced transcription of CD25, CD39, and CD73. Adoptive transfer of Tregs confirmed that Nox2-deficient cells had greater inhibitory effects on Ang II–induced heart remodeling than WT cells. These results identify a previously unrecognized role of Nox2 in modulating suppression of Tregs, which acts to enhance hypertension and cardiac remodeling.
Authors
Amber Emmerson, Silvia Cellone Trevelin, Heloise Mongue-Din, Pablo D. Becker, Carla Ortiz, Lesley A. Smyth, Qi Peng, Raul Elgueta, Greta Sawyer, Aleksandar Ivetic, Robert I. Lechler, Giovanna Lombardi, Ajay M. Shah
×Abstract
BACKGROUND. The effect of a brief analytical treatment interruption (ATI) on the HIV-1 latent reservoir of individuals who initiate antiretroviral therapy (ART) during chronic infection is unknown. METHODS. We evaluated the impact of transient viremia on the latent reservoir in participants who underwent an ATI and at least 6 months of subsequent viral suppression in a clinical trial testing the effect of passive infusion of the broadly neutralizing Ab VRC01 during ATI. RESULTS. Measures of total HIV-1 DNA, cell-associated RNA, and infectious units per million cells (IUPM) (measured by quantitative viral outgrowth assay [QVOA]) were not statistically different before or after ATI. Phylogenetic analyses of HIV-1 env sequences from QVOA and proviral DNA demonstrated little change in the composition of the virus populations comprising the pre- and post-ATI reservoir. Expanded clones were common in both QVOA and proviral DNA sequences. The frequency of clonal populations differed significantly between QVOA viruses, proviral DNA sequences, and the viruses that reactivated in vivo. CONCLUSIONS. The results indicate that transient viremia from ATI does not substantially alter measures of the latent reservoir, that clonal expansion is prevalent within the latent reservoir, and that characterization of latent viruses that can reactivate in vivo remains challenging. TRIAL REGISTRATION. ClinicalTrials.gov NCT02463227 FUNDING. Funding was provided by the NIH.
Authors
D. Brenda Salantes, Yu Zheng, Felicity Mampe, Tuhina Srivastava, Subul Beg, Jun Lai, Jonathan Z. Li, Randall L. Tressler, Richard A. Koup, James Hoxie, Mohamed Abdel-Mohsen, Scott Sherrill-Mix, Kevin McCormick, E. Turner Overton, Frederic D. Bushman, Gerald H. Learn, Robert F. Siliciano, Janet M. Siliciano, Pablo Tebas, Katharine J. Bar
×Abstract
Protease-activated receptor 2 (PAR-2), an airway epithelial pattern recognition receptor (PRR), participates in the genesis of house dust mite–induced (HDM-induced) asthma. Here, we hypothesized that lung endothelial cells and proangiogenic hematopoietic progenitor cells (PACs) that express high levels of PAR-2 contribute to the initiation of atopic asthma. HDM extract (HDME) protease allergens were found deep in the airway mucosa and breaching the endothelial barrier. Lung endothelial cells and PACs released the Th2-promoting cytokines IL-1α and GM-CSF in response to HDME, and the endothelium had PAC-derived VEGF-C–dependent blood vessel sprouting. Blockade of the angiogenic response by inhibition of VEGF-C signaling lessened the development of inflammation and airway remodeling in the HDM model. Reconstitution of the bone marrow in WT mice with PAR-2–deficient bone marrow also reduced airway inflammation and remodeling. Adoptive transfer of PACs that had been exposed to HDME induced angiogenesis and Th2 inflammation with remodeling similar to that induced by allergen challenge. Our findings identify that lung endothelium and PACs in the airway sense allergen and elicit an angiogenic response that is central to the innate nonimmune origins of Th2 inflammation.
Authors
Kewal Asosingh, Kelly Weiss, Kimberly Queisser, Nicholas Wanner, Mei Yin, Mark Aronica, Serpil Erzurum
×Abstract
Receptor tyrosine kinases (RTKs) are important drivers of cancers. In addition to genomic alterations, aberrant activation of WT RTKs plays an important role in driving cancer progression. However, the mechanisms underlying how RTKs drive prostate cancer remain incompletely characterized. Here we show that non-proteolytic ubiquitination of RTK regulates its kinase activity and contributes to RTK-mediated prostate cancer metastasis. TRAF4, an E3 ubiquitin ligase, is highly expressed in metastatic prostate cancer. We demonstrated here that it is a key player in regulating RTK-mediated prostate cancer metastasis. We further identified TrkA, a neurotrophin RTK, as a TRAF4-targeted ubiquitination substrate that promotes cancer cell invasion and found that inhibition of TrkA activity abolished TRAF4-dependent cell invasion. TRAF4 promoted K27- and K29-linked ubiquitination at the TrkA kinase domain and increased its kinase activity. Mutation of TRAF4-targeted ubiquitination sites abolished TrkA tyrosine autophosphorylation and its interaction with downstream proteins. TRAF4 knockdown also suppressed nerve growth factor (NGF) stimulated TrkA downstream p38 MAPK activation and invasion-associated gene expression. Furthermore, elevated TRAF4 levels significantly correlated with increased NGF-stimulated invasion–associated gene expression in prostate cancer patients, indicating that this signaling axis is significantly activated during oncogenesis. Our results revealed a posttranslational modification mechanism contributing to aberrant non-mutated RTK activation in cancer cells.
Authors
Ramesh Singh, Dileep Karri, Hong Shen, Jiangyong Shao, Subhamoy Dasgupta, Shixia Huang, Dean P. Edwards, Michael M. Ittmann, Bert W. O’Malley, Ping Yi
×Abstract
Jumonji D3 (JMJD3) histone demethylase epigenetically regulates development and differentiation, immunity, and tumorigenesis by demethylating a gene repression histone mark, H3K27-me3, but a role for JMJD3 in metabolic regulation has not been described. SIRT1 deacetylase maintains energy balance during fasting by directly activating both hepatic gluconeogenic and mitochondrial fatty acid β-oxidation genes, but the underlying epigenetic and gene-specific mechanisms remain unclear. In this study, JMJD3 was identified unexpectedly as a gene-specific transcriptional partner of SIRT1 and epigenetically activated mitochondrial β-oxidation, but not gluconeogenic, genes during fasting. Mechanistically, JMJD3, together with SIRT1 and the nuclear receptor PPARα, formed a positive autoregulatory loop upon fasting-activated PKA signaling and epigenetically activated β-oxidation–promoting genes, including Fgf21, Cpt1a, and Mcad. Liver-specific downregulation of JMJD3 resulted in intrinsic defects in β-oxidation, which contributed to hepatosteatosis as well as glucose and insulin intolerance. Remarkably, the lipid-lowering effects by JMJD3 or SIRT1 in diet-induced obese mice were mutually interdependent. JMJD3 histone demethylase may serve as an epigenetic drug target for obesity, hepatosteatosis, and type 2 diabetes that allows selective lowering of lipid levels without increasing glucose levels.
Authors
Sunmi Seok, Young-Chae Kim, Sangwon Byun, Sunge Choi, Zhen Xiao, Naoki Iwamori, Yang Zhang, Chaochen Wang, Jian Ma, Kai Ge, Byron Kemper, Jongsook Kim Kemper
×Abstract
It is critical for survival to assign positive or negative valence to salient stimuli in a correct manner. Accordingly, harmful stimuli and internal states characterized by perturbed homeostasis are accompanied by discomfort, unease, and aversion. Aversive signaling causes extensive suffering during chronic diseases, including inflammatory conditions, cancer, and depression. Here, we investigated the role of melanocortin 4 receptors (MC4Rs) in aversive processing using genetically modified mice and a behavioral test in which mice avoid an environment that they have learned to associate with aversive stimuli. In normal mice, robust aversions were induced by systemic inflammation, nausea, pain, and κ opioid receptor–induced dysphoria. In sharp contrast, mice lacking MC4Rs displayed preference or indifference toward the aversive stimuli. The unusual flip from aversion to reward in mice lacking MC4Rs was dopamine dependent and associated with a change from decreased to increased activity of the dopamine system. The responses to aversive stimuli were normalized when MC4Rs were reexpressed on dopamine D1 receptor–expressing cells or in the striatum of mice otherwise lacking MC4Rs. Furthermore, activation of arcuate nucleus proopiomelanocortin neurons projecting to the ventral striatum increased the activity of striatal neurons in an MC4R-dependent manner and elicited aversion. Our findings demonstrate that melanocortin signaling through striatal MC4Rs is critical for assigning negative motivational valence to harmful stimuli.
Authors
Anna Mathia Klawonn, Michael Fritz, Anna Nilsson, Jordi Bonaventura, Kiseko Shionoya, Elahe Mirrasekhian, Urban Karlsson, Maarit Jaarola, Björn Granseth, Anders Blomqvist, Michael Michaelides, David Engblom
×Abstract
HIV infection changes the lymph node (LN) tissue architecture, potentially impairing the immunologic response to antigenic challenge. The tissue-resident immune cell dynamics in virologically suppressed HIV+ patients on combination antiretroviral therapy (cART) are not clear. We obtained LN biopsies before and 10 to 14 days after trivalent seasonal influenza immunization from healthy controls (HCs) and HIV+ volunteers on cART to investigate CD4+ T follicular helper (Tfh) and B cell dynamics by flow cytometry and quantitative imaging analysis. Prior to vaccination, compared with those in HCs, HIV+ LNs exhibited an altered follicular architecture, but harbored higher numbers of Tfh cells and increased IgG+ follicular memory B cells. Moreover, Tfh cell numbers were dependent upon preservation of the follicular dendritic cell (FDC) network and were predictive of the magnitude of the vaccine-induced IgG responses. Interestingly, postvaccination LN samples in HIV+ participants had significantly (P = 0.0179) reduced Tfh cell numbers compared with prevaccination samples, without evidence for peripheral Tfh (pTfh) cell reduction. We conclude that influenza vaccination alters the cellularity of draining LNs of HIV+ persons in conjunction with development of antigen-specific humoral responses. The underlying mechanism of Tfh cell decline warrants further investigation, as it could bear implications for the rational design of HIV vaccines.
Authors
Eirini Moysi, Suresh Pallikkuth, Lesley R. De Armas, Louis E. Gonzalez, David Ambrozak, Varghese George, David Huddleston, Rajendra Pahwa, Richard A. Koup, Constantinos Petrovas, Savita Pahwa
×Abstract
Although it has been reported that hypoxia inducible factor 2 α (Hif2a), a major transcriptional factor inducible by low oxygen tension, is expressed in the mouse uterus during embryo implantation, its role in pregnancy outcomes remains unclear. This study aimed to clarify functions of uterine HIF using transgenic mouse models. Mice with deletion of Hif2a in the whole uterus (Hif2a-uKO mice) showed infertility due to implantation failure. Supplementation with progesterone (P4) and leukemia inhibitory factor (LIF) restored decidual growth arrest and aberrant position of implantation sites in Hif2a-uKO mice, respectively, but did not rescue pregnancy failure. Histological analyses in Hif2a-uKO mice revealed persistence of the intact luminal epithelium, which blocked direct contact between stroma and embryo, inactivation of PI3K-AKT pathway (embryonic survival signal), and failed embryo invasion. Mice with stromal deletion of Hif2a (Hif2a-sKO mice) showed infertility with impaired embryo invasion and those with epithelial deletion of Hif2a (Hif2a-eKO mice) showed normal fertility, suggesting the importance of stromal HIF2α in embryo invasion. This was reflected in reduced expression of membrane type 2 metalloproteinase (MT2-MMP), lysyl oxidase (LOX), VEGF, and adrenomedullin (ADM) in Hif2a-uKO stroma at the attachment site, suggesting that stromal HIF2α regulates these mediators to support blastocyst invasion. These findings provide new insight that stromal HIF2α allows trophoblast invasion through detachment of the luminal epithelium and activation of an embryonic survival signal.
Authors
Leona Matsumoto, Yasushi Hirota, Tomoko Saito-Fujita, Norihiko Takeda, Tomoki Tanaka, Takehiro Hiraoka, Shun Akaeda, Hidetoshi Fujita, Ryoko Shimizu-Hirota, Shota Igaue, Mitsunori Matsuo, Hirofumi Haraguchi, Mayuko Saito-Kanatani, Tomoyuki Fujii, Yutaka Osuga
Copyright © 2024 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)