Issue published March 15, 2021 Previous issue | Next issue
On the cover: Protecting right ventricular function in pulmonary hypertension
In this issue, Frump et al. explore the mechanisms underlying better right ventricular function in women relative to men with pulmonary arterial hypertension. Using patient samples and multiple preclinical models, they find that estrogen upregulates apelin — a peptide that stimulates cardiac contractility — by increasing expression of the cytokine bone morphogenetic protein receptor 2 (BMPR2), which has an estrogen response element in its promoter. The cover image shows localization of estrogen receptor(magenta) and nuclei (blue, DAPI staining) in human right ventricular cardiomyocytes (visualized by differential interference contrast).
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Review Series
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Abstract
The tumor microenvironment profoundly influences the behavior of recruited leukocytes and tissue-resident immune cells. These immune cells, which inherently have environmentally driven plasticity necessary for their roles in tissue homeostasis, dynamically interact with tumor cells and the tumor stroma and play critical roles in determining the course of disease. Among these immune cells, neutrophils were once considered much more static within the tumor microenvironment; however, some of these earlier assumptions were the product of the notorious difficulty in manipulating neutrophils in vitro. Technological advances that allow us to study neutrophils in context are now revealing the true roles of neutrophils in the tumor microenvironment. Here we discuss recent data generated by some of these tools and how these data might be synthesized into more elegant ways of targeting these powerful and abundant effector immune cells in the clinic.
Authors
Amanda J. McFarlane, Frédéric Fercoq, Seth B. Coffelt, Leo M. Carlin
×Abstract
Continued thinning of the atmospheric ozone, which protects the earth from damaging ultraviolet radiation (UVR), will result in elevated levels of UVR reaching the earth’s surface, leading to a drastic increase in the incidence of skin cancer. In addition to promoting carcinogenesis in skin cells, UVR is a potent extrinsic driver of age-related changes in the skin known as “photoaging.” We are in the preliminary stages of understanding of the role of intrinsic aging in melanoma, and the tumor-permissive effects of photoaging on the skin microenvironment remain largely unexplored. In this Review, we provide an overview of the impact of UVR on the skin microenvironment, addressing changes that converge or diverge with those observed in intrinsic aging. Intrinsic and extrinsic aging promote phenotypic changes to skin cell populations that alter fundamental processes such as melanogenesis, extracellular matrix deposition, inflammation, and immune response. Given the relevance of these processes in cancer, we discuss how photoaging might render the skin microenvironment permissive to melanoma progression.
Authors
Asurayya Worrede, Stephen M. Douglass, Ashani T. Weeraratna
×Abstract
Many solid cancers metastasize to the bone and bone marrow (BM). This process may occur even before the diagnosis of primary tumors, as evidenced by the discovery of disseminated tumor cells (DTCs) in patients without occult malignancies. The cellular fates and metastatic progression of DTCs are determined by complicated interactions between cancer cells and BM niches. Not surprisingly, these niches also play important roles in normal biology, including homeostasis and turnover of skeletal and hematopoiesis systems. In this Review, we summarize recent findings on functions of BM niches in bone metastasis (BoMet), particularly during the early stage of colonization. In light of the rich knowledge of hematopoiesis and osteogenesis, we highlight how DTCs may progress into overt BoMet by taking advantage of niche cells and their activities in tissue turnover, especially those related to immunomodulation and bone repair.
Authors
Aaron M. Muscarella, Sergio Aguirre, Xiaoxin Hao, Sarah M. Waldvogel, Xiang H.-F. Zhang
×Abstract
Treatment resistance leads to cancer patient mortality. Therapeutic approaches that employ synthetic lethality to target mutational vulnerabilities in key tumor cell signaling pathways have proven effective in overcoming therapeutic resistance in some cancers. Yet, tumors are organs composed of malignant cells residing within a cellular and noncellular stroma. Tumor evolution and resistance to anticancer treatment are mediated through a dynamic and reciprocal dialogue with the tumor microenvironment (TME). Accordingly, expanding tumor cell synthetic lethality to encompass contextual synthetic lethality has the potential to eradicate tumors by targeting critical TME circuits that promote tumor progression and therapeutic resistance. In this Review, we summarize current knowledge about the TME and discuss its role in treatment. We outline the concept of tumor cell–specific synthetic lethality and describe therapeutic approaches to expand this paradigm to leverage TME synthetic lethality to improve cancer therapy.
Authors
Kevin J. Metcalf, Alaa Alazzeh, Zena Werb, Valerie M. Weaver
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Commentaries
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Abstract
The enteric nervous system mediates reflexes independently of the brain and spinal cord and transmits signals bidirectionally between the gut and the brain. Hirschsprung disease and chronic intestinal pseudo-obstruction (CIPO) and pediatric CIPO are examples of congenital defects that impair gastrointestinal motility. In this issue of the JCI, Thuy-Linh Le et al. analyzed eight patients with defects in tissue that arose from the neural crest. The patients carried homozygous or heterozygous variants in ERBB3 or ERBB2, which encode transmembrane epidermal growth factor receptors that bind neuroregulin 1 (NRG1). Notably, the genetic variants resulted in loss of function with decreased expression or aberrant phosphorylation of the ERBB3/ERBB2 receptors. Experiments using mice revealed that Erbb3 and Erbb2 were expressed in enteric neuronal progenitor cells. This study is an outstanding example of descriptive observation that begs for mechanistic exploration to reveal precisely how the NRG1/ERBB3/ERBB2 pathway influences ENS development.
Authors
Michael D. Gershon
×Abstract
Nonalcoholic fatty liver disease (NAFLD) results in the accumulation of fat in the liver and can progress as an inflammatory disorder with considerable vascular endothelial dysfunction known as nonalcoholic steatohepatitis (NASH). Inflammatory signals can trigger the expression of vascular cell adhesion molecule 1 (VCAM-1) on endothelial cells. VCAM-1 is a surface protein that induces adherence and extravasation of monocytes to blood vessels. In this issue of the JCI, Furuta et al. report on their sequencing of RNA transcripts from the livers of mice fed a NASH-inducing diet. VCAM-1 was upregulated in the whole liver as well as liver sinusoidal endothelial cells (LSECs). When the researchers incubated LSECs with palmitate, a toxic lipid, VCAM-1 was upregulated. Notably, inhibiting VCAM-1 in the NASH model reduced VCAM-1 expression, lessened infiltrating macrophages, and mitigated fibrosis. This study connects steatosis to endothelial dysfunction and inflammation and suggests that targeting VCAM-1 may address fibrosis in patients with NASH.
Authors
Rotonya M. Carr
×Abstract
Interest in omega-3 fatty acids (colloquially known as fish oils) to lower residual cardiovascular risk in statin-treated patients has increased markedly in the wake of recent cardiovascular outcome trials. The triglyceride-lowering effects of omega-3 fatty acids are generally thought to occur by reduced hepatic VLDL production. In this issue of the JCI, Grevengoed et al. used mouse models and human plasma samples to reveal an additional mechanism whereby these polyunsaturated fatty acids can lower plasma triglycerides. Their findings indicate that omega-3 fatty acid–derived N-acyl taurines (NATs) greatly accumulate in bile and also in plasma following omega-3 supplementation. The authors further show that one of these NATs (C22:6 NAT) inhibited intestinal triglyceride hydrolysis and lipid absorption, which resulted in lower plasma triglycerides and protection against hepatic triacylglycerol accumulation in mice fed a high-fat diet. The findings open a potential avenue for triglyceride lowering by omega-3 fatty acids conjugated to taurine.
Authors
Karin E. Bornfeldt
×Abstract
Leber’s hereditary optic neuropathy (LHON) is the most common mitochondrial disease and in most cases is caused by mutations in mitochondrial DNA–encoded (mtDNA-encoded) respiratory complex I subunit ND1, ND4, or ND6. In this issue of the JCI, Stenton et al. describe biallelic mutations in a nuclear DNA–encoded gene, DNAJC30, establishing recessively inherited LHON (arLHON). Functional studies suggest that DNAJC30 is a protein chaperone required for exchange of damaged complex I subunits. Hallmark mtDNA LHON features were also found in arLHON, including incomplete penetrance, male predominance, and positive response to idebenone therapy. These results extend complex I–deficient phenotypes to include recessively inherited optic neuropathy, with important clinical implications for genetic counseling and therapeutic considerations.
Authors
Janey L. Wiggs
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Research Articles
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Abstract
Women with pulmonary arterial hypertension (PAH) exhibit better right ventricular (RV) function and survival than men; however, the underlying mechanisms are unknown. We hypothesized that 17β-estradiol (E2), through estrogen receptor α (ER-α), attenuates PAH-induced RV failure (RVF) by upregulating the procontractile and prosurvival peptide apelin via a BMPR2-dependent mechanism. We found that ER-α and apelin expression were decreased in RV homogenates from patients with RVF and from rats with maladaptive (but not adaptive) RV remodeling. RV cardiomyocyte apelin abundance increased in vivo or in vitro after treatment with E2 or ER-α agonist. Studies employing ER-α–null or ER-β–null mice, ER-α loss-of-function mutant rats, or siRNA demonstrated that ER-α is necessary for E2 to upregulate RV apelin. E2 and ER-α increased BMPR2 in pulmonary hypertension RVs and in isolated RV cardiomyocytes, associated with ER-α binding to the Bmpr2 promoter. BMPR2 is required for E2-mediated increases in apelin abundance, and both BMPR2 and apelin are necessary for E2 to exert RV-protective effects. E2 or ER-α agonist rescued monocrotaline pulmonary hypertension and restored RV apelin and BMPR2. We identified what we believe to be a novel cardioprotective E2/ER-α/BMPR2/apelin axis in the RV. Harnessing this axis may lead to novel RV-targeted therapies for PAH patients of either sex.
Authors
Andrea L. Frump, Marjorie Albrecht, Bakhtiyor Yakubov, Sandra Breuils-Bonnet, Valérie Nadeau, Eve Tremblay, Francois Potus, Junichi Omura, Todd Cook, Amanda Fisher, Brooke Rodriguez, R. Dale Brown, Kurt R. Stenmark, C. Dustin Rubinstein, Kathy Krentz, Diana M. Tabima, Rongbo Li, Xin Sun, Naomi C. Chesler, Steeve Provencher, Sebastien Bonnet, Tim Lahm
×Abstract
Most clinically used anticancer mAbs are of the IgG isotype, which can eliminate tumor cells through NK cell–mediated antibody-dependent cellular cytotoxicity and macrophage-mediated antibody-dependent phagocytosis. IgG, however, ineffectively recruits neutrophils as effector cells. IgA mAbs induce migration and activation of neutrophils through the IgA Fc receptor (FcαRI) but are unable to activate NK cells and have poorer half-life. Here, we combined the agonistic activity of IgG mAbs and FcαRI targeting in a therapeutic bispecific antibody format. The resulting TrisomAb molecules recruited NK cells, macrophages, and neutrophils as effector cells for eradication of tumor cells in vitro and in vivo. Moreover, TrisomAb had long in vivo half-life and strongly decreased B16F10gp75 tumor outgrowth in mice. Importantly, neutrophils of colorectal cancer patients effectively eliminated tumor cells in the presence of anti-EGFR TrisomAb but were less efficient in mediating killing in the presence of IgG anti-EGFR mAb (cetuximab). The clinical application of TrisomAb may provide potential alternatives for cancer patients who do not benefit from current IgG mAb therapy.
Authors
Niels Heemskerk, Mandy Gruijs, A. Robin Temming, Marieke H. Heineke, Dennis Y. Gout, Tessa Hellingman, Cornelis W. Tuk, Paula J. Winter, Suzanne Lissenberg-Thunnissen, Arthur E.H. Bentlage, Marco de Donatis, Marijn Bögels, Thies Rösner, Thomas Valerius, Jantine E. Bakema, Gestur Vidarsson, Marjolein van Egmond
×Abstract
Glioblastoma (GBM) is composed of heterogeneous tumor cell populations, including those with stem cell properties, termed glioma stem cells (GSCs). GSCs are innately less radiation sensitive than the tumor bulk and are believed to drive GBM formation and recurrence after repeated irradiation. However, it is unclear how GSCs adapt to escape the toxicity of repeated irradiation used in clinical practice. To identify important mediators of adaptive radioresistance in GBM, we generated radioresistant human and mouse GSCs by exposing them to repeat cycles of irradiation. Surviving subpopulations acquired strong radioresistance in vivo, which was accompanied by a reduction in cell proliferation and an increase in cell-cell adhesion and N-cadherin expression. Increasing N-cadherin expression rendered parental GSCs radioresistant, reduced their proliferation, and increased their stemness and intercellular adhesive properties. Conversely, radioresistant GSCs lost their acquired phenotypes upon CRISPR/Cas9-mediated knockout of N-cadherin. Mechanistically, elevated N-cadherin expression resulted in the accumulation of β-catenin at the cell surface, which suppressed Wnt/β-catenin proliferative signaling, reduced neural differentiation, and protected against apoptosis through Clusterin secretion. N-cadherin upregulation was induced by radiation-induced IGF1 secretion, and the radiation resistance phenotype could be reverted with picropodophyllin, a clinically applicable blood-brain-barrier permeable IGF1 receptor inhibitor, supporting clinical translation.
Authors
Satoru Osuka, Dan Zhu, Zhaobin Zhang, Chaoxi Li, Christian T. Stackhouse, Oltea Sampetrean, Jeffrey J. Olson, G. Yancey Gillespie, Hideyuki Saya, Christopher D. Willey, Erwin G. Van Meir
×Abstract
Leber’s hereditary optic neuropathy (LHON) is the most frequent mitochondrial disease and was the first to be genetically defined by a point mutation in mitochondrial DNA (mtDNA). A molecular diagnosis is achieved in up to 95% of cases, the vast majority of which are accounted for by 3 mutations within mitochondrial complex I subunit–encoding genes in the mtDNA (mtLHON). Here, we resolve the enigma of LHON in the absence of pathogenic mtDNA mutations. We describe biallelic mutations in a nuclear encoded gene, DNAJC30, in 33 unsolved patients from 29 families and establish an autosomal recessive mode of inheritance for LHON (arLHON), which to date has been a prime example of a maternally inherited disorder. Remarkably, all hallmarks of mtLHON were recapitulated, including incomplete penetrance, male predominance, and significant idebenone responsivity. Moreover, by tracking protein turnover in patient-derived cell lines and a DNAJC30-knockout cellular model, we measured reduced turnover of specific complex I N-module subunits and a resultant impairment of complex I function. These results demonstrate that DNAJC30 is a chaperone protein needed for the efficient exchange of complex I subunits exposed to reactive oxygen species and integral to a mitochondrial complex I repair mechanism, thereby providing the first example to our knowledge of a disease resulting from impaired exchange of assembled respiratory chain subunits.
Authors
Sarah L. Stenton, Natalia L. Sheremet, Claudia B. Catarino, Natalia A. Andreeva, Zahra Assouline, Piero Barboni, Ortal Barel, Riccardo Berutti, Igor Bychkov, Leonardo Caporali, Mariantonietta Capristo, Michele Carbonelli, Maria L. Cascavilla, Peter Charbel Issa, Peter Freisinger, Sylvie Gerber, Daniele Ghezzi, Elisabeth Graf, Juliana Heidler, Maja Hempel, Elise Heon, Yulya S. Itkis, Elisheva Javasky, Josseline Kaplan, Robert Kopajtich, Cornelia Kornblum, Reka Kovacs-Nagy, Tatiana D. Krylova, Wolfram S. Kunz, Chiara La Morgia, Costanza Lamperti, Christina Ludwig, Pedro F. Malacarne, Alessandra Maresca, Johannes A. Mayr, Jana Meisterknecht, Tatiana A. Nevinitsyna, Flavia Palombo, Ben Pode-Shakked, Maria S. Shmelkova, Tim M. Strom, Francesca Tagliavini, Michal Tzadok, Amelie T. van der Ven, Catherine Vignal-Clermont, Matias Wagner, Ekaterina Y. Zakharova, Nino V. Zhorzholadze, Jean-Michel Rozet, Valerio Carelli, Polina G. Tsygankova, Thomas Klopstock, Ilka Wittig, Holger Prokisch
×Abstract
Chronic HIV-1 infection is generally characterized by progressive CD4+ T cell depletion due to direct and bystander death that is closely associated with persistent HIV-1 replication and an inflammatory environment in vivo. The mechanisms underlying the loss of CD4+ T cells in patients with chronic HIV-1 infection are incompletely understood. In this study, we simultaneously monitored caspase-1 and caspase-3 activation in circulating CD4+ T cells, which revealed that pyroptotic and apoptotic CD4+ T cells are distinct cell populations with different phenotypic characteristics. Levels of pyroptosis and apoptosis in CD4+ T cells were significantly elevated during chronic HIV-1 infection, and decreased following effective antiretroviral therapy. Notably, the occurrence of pyroptosis was further confirmed by elevated gasdermin D activation in lymph nodes of HIV-1–infected individuals. Mechanistically, caspase-1 activation closely correlated with the inflammatory marker expression and was shown to occur through NLRP3 inflammasome activation driven by virus-dependent and/or -independent ROS production, while caspase-3 activation in CD4+ T cells was more closely related to T cell activation status. Hence, our findings show that NLRP3-dependent pyroptosis plays an essential role in CD4+ T cell loss in HIV-1–infected patients and implicate pyroptosis signaling as a target for anti–HIV-1 treatment.
Authors
Chao Zhang, Jin-Wen Song, Hui-Huang Huang, Xing Fan, Lei Huang, Jian-Ning Deng, Bo Tu, Kun Wang, Jing Li, Ming-Ju Zhou, Cui-Xian Yang, Qi-Wen Zhao, Tao Yang, Li-Feng Wang, Ji-Yuan Zhang, Ruo-Nan Xu, Yan-Mei Jiao, Ming Shi, Feng Shao, Rafick-Pierre Sékaly, Fu-Sheng Wang
×Abstract
Tyro3, AXL, and MerTK (TAM) receptors are activated in macrophages in response to tissue injury and as such have been proposed as therapeutic targets to promote inflammation resolution during sterile wound healing, including myocardial infarction. Although the role of MerTK in cardioprotection is well characterized, the unique role of the other structurally similar TAMs, and particularly AXL, in clinically relevant models of myocardial ischemia/reperfusion infarction (IRI) is comparatively unknown. Utilizing complementary approaches, validated by flow cytometric analysis of human and murine macrophage subsets and conditional genetic loss and gain of function, we uncover a maladaptive role for myeloid AXL during IRI in the heart. Cross signaling between AXL and TLR4 in cardiac macrophages directed a switch to glycolytic metabolism and secretion of proinflammatory IL-1β, leading to increased intramyocardial inflammation, adverse ventricular remodeling, and impaired contractile function. AXL functioned independently of cardioprotective MerTK to reduce the efficacy of cardiac repair, but like MerTK, was proteolytically cleaved. Administration of a selective small molecule AXL inhibitor alone improved cardiac healing, which was further enhanced in combination with blockade of MerTK cleavage. These data support further exploration of macrophage TAM receptors as therapeutic targets for myocardial infarction.
Authors
Matthew DeBerge, Kristofor Glinton, Manikandan Subramanian, Lisa D. Wilsbacher, Carla V. Rothlin, Ira Tabas, Edward B. Thorp
×Abstract
In inherited neurodevelopmental diseases, pathogenic processes unique to critical periods during early brain development may preclude the effectiveness of gene modification therapies applied later in life. We explored this question in a mouse model of DYT1 dystonia, a neurodevelopmental disease caused by a loss-of-function mutation in the TOR1A gene encoding torsinA. To define the temporal requirements for torsinA in normal motor function and gene replacement therapy, we developed a mouse line enabling spatiotemporal control of the endogenous torsinA allele. Suppressing torsinA during embryogenesis caused dystonia-mimicking behavioral and neuropathological phenotypes. Suppressing torsinA during adulthood, however, elicited no discernible abnormalities, establishing an essential requirement for torsinA during a developmental critical period. The developing CNS exhibited a parallel “therapeutic critical period” for torsinA repletion. Although restoring torsinA in juvenile DYT1 mice rescued motor phenotypes, there was no benefit from adult torsinA repletion. These data establish a unique requirement for torsinA in the developing nervous system and demonstrate that the critical period genetic insult provokes permanent pathophysiology mechanistically delinked from torsinA function. These findings imply that to be effective, torsinA-based therapeutic strategies must be employed early in the course of DYT1 dystonia.
Authors
Jay Li, Daniel S. Levin, Audrey J. Kim, Samuel S. Pappas, William T. Dauer
×Abstract
Familial exudative vitreoretinopathy (FEVR) is a severe retinal vascular disease that causes blindness. FEVR has been linked to mutations in several genes associated with inactivation of the Norrin/β-catenin signaling pathway, but these account for only approximately 50% of cases. We report that mutations in α-catenin (CTNNA1) cause FEVR by overactivating the β-catenin pathway and disrupting cell adherens junctions. We identified 3 heterozygous mutations in CTNNA1 (p.F72S, p.R376Cfs*27, and p.P893L) by exome sequencing and further demonstrated that FEVR-associated mutations led to overactivation of Norrin/β-catenin signaling as a result of impaired protein interactions within the cadherin-catenin complex. The clinical features of FEVR were reproduced in mice lacking Ctnna1 in vascular endothelial cells (ECs) or with overactivated β-catenin signaling by an EC-specific gain-of-function allele of Ctnnb1. In isolated mouse lung ECs, both CTNNA1-P893L and F72S mutants failed to rescue either the disrupted F-actin arrangement or the VE-cadherin and CTNNB1 distribution. Moreover, we discovered that compound heterozygous Ctnna1 F72S and a deletion allele could cause a similar phenotype. Furthermore, in a FEVR family, we identified a mutation of LRP5, which activates Norrin/β-catenin signaling, and the corresponding knockin mice exhibited a partial FEVR-like phenotype. Our study demonstrates that the precise regulation of β-catenin activation is critical for retinal vascular development and provides new insights into the pathogenesis of FEVR.
Authors
Xianjun Zhu, Mu Yang, Peiquan Zhao, Shujin Li, Lin Zhang, Lulin Huang, Yi Huang, Ping Fei, Yeming Yang, Shanshan Zhang, Huijuan Xu, Ye Yuan, Xiang Zhang, Xiong Zhu, Shi Ma, Fang Hao, Periasamy Sundaresan, Weiquan Zhu, Zhenglin Yang
×Abstract
Medulloblastoma is an aggressive pediatric brain tumor that can be driven by misactivation of the Hedgehog (HH) pathway. CDK6 is a critical effector of oncogenic HH signaling, but attempts to target the HH pathway in medulloblastoma have been encumbered by resistance to single-agent molecular therapy. We identified mechanisms of resistance to CDK6 inhibition in HH-associated medulloblastoma by performing orthogonal CRISPR and CRISPR interference screens in medulloblastoma cells treated with a CDK4/6 inhibitor and RNA-Seq of a mouse model of HH-associated medulloblastoma with genetic deletion of Cdk6. Our concordant in vitro and in vivo data revealed that decreased ribosomal protein expression underlies resistance to CDK6 inhibition in HH-associated medulloblastoma, leading to ER stress and activation of the unfolded protein response (UPR). These pathways increased the activity of enzymes producing Smoothened-activating (SMO-activating) sterol lipids that sustained oncogenic HH signaling in medulloblastoma despite cell-cycle attenuation. We consistently demonstrated that concurrent genetic deletion or pharmacological inhibition of CDK6 and HSD11ß2, an enzyme producing SMO-activating lipids, additively blocked cancer growth in multiple mouse genetic models of HH-associated medulloblastoma. Our data reveal what we believe to be a novel pathway of resistance to CDK4/6 inhibition as well as a novel combination therapy to treat the most common malignant brain tumor in children.
Authors
Vikas Daggubati, Jordan Hochstelter, Anirudh Bommireddy, Abrar Choudhury, Alexis Leigh Krup, Pervinder Kaur, Pakteema Tong, Amy Li, Libin Xu, Jeremy F. Reiter, David R. Raleigh
×Abstract
T cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematologic malignancy with inferior outcome compared with that of B cell ALL. Here, we show that Runt-related transcription factor 2 (RUNX2) was upregulated in high-risk T-ALL with KMT2A rearrangements (KMT2A-R) or an immature immunophenotype. In KMT2A-R cells, we identified RUNX2 as a direct target of the KMT2A chimeras, where it reciprocally bound the KMT2A promoter, establishing a regulatory feed-forward mechanism. Notably, RUNX2 was required for survival of immature and KMT2A-R T-ALL cells in vitro and in vivo. We report direct transcriptional regulation of CXCR4 signaling by RUNX2, thereby promoting chemotaxis, adhesion, and homing to medullary and extramedullary sites. RUNX2 enabled these energy-demanding processes by increasing metabolic activity in T-ALL cells through positive regulation of both glycolysis and oxidative phosphorylation. Concurrently, RUNX2 upregulation increased mitochondrial dynamics and biogenesis in T-ALL cells. Finally, as a proof of concept, we demonstrate that immature and KMT2A-R T-ALL cells were vulnerable to pharmacological targeting of the interaction between RUNX2 and its cofactor CBFβ. In conclusion, we show that RUNX2 acts as a dependency factor in high-risk subtypes of human T-ALL through concomitant regulation of tumor metabolism and leukemic cell migration.
Authors
Filip Matthijssens, Nitesh D. Sharma, Monique Nysus, Christian K. Nickl, Huining Kang, Dominique R. Perez, Beatrice Lintermans, Wouter Van Loocke, Juliette Roels, Sofie Peirs, Lisa Demoen, Tim Pieters, Lindy Reunes, Tim Lammens, Barbara De Moerloose, Filip Van Nieuwerburgh, Dieter L. Deforce, Laurence C. Cheung, Rishi S. Kotecha, Martijn D.P. Risseeuw, Serge Van Calenbergh, Takeshi Takarada, Yukio Yoneda, Frederik W. van Delft, Richard B. Lock, Seth D. Merkley, Alexandre Chigaev, Larry A. Sklar, Charles G. Mullighan, Mignon L. Loh, Stuart S. Winter, Stephen P. Hunger, Steven Goossens, Eliseo F. Castillo, Wojciech Ornatowski, Pieter Van Vlierberghe, Ksenia Matlawska-Wasowska
×Abstract
The effectiveness of virus-specific strategies, including administered HIV-specific mAbs, to target cells that persistently harbor latent, rebound-competent HIV genomes during combination antiretroviral therapy (cART) has been limited by inefficient induction of viral protein expression. To examine antibody-mediated viral reservoir targeting without a need for viral induction, we used an anti-CD4 mAb to deplete both infected and uninfected CD4+ T cells. Ten rhesus macaques infected with barcoded SIVmac239M received cART for 93 weeks starting 4 days after infection. During cART, 5 animals received 5 to 6 anti-CD4 antibody administrations and CD4+ T cell populations were then allowed 1 year on cART to recover. Despite profound CD4+ T cell depletion in blood and lymph nodes, time to viral rebound following cART cessation was not significantly delayed in anti-CD4–treated animals compared with controls. Viral reactivation rates, determined based on rebounding SIVmac239M clonotype proportions, also were not significantly different in CD4-depleted animals. Notably, antibody-mediated depletion was limited in rectal tissue and negligible in lymphoid follicles. These results suggest that, even if robust viral reactivation can be achieved, antibody-mediated viral reservoir depletion may be limited in key tissue sites.
Authors
Adrienne E. Swanstrom, Taina T. Immonen, Kelli Oswald, Cathi Pyle, James A. Thomas, William J. Bosche, Lorna Silipino, Michael Hull, Laura Newman, Vicky Coalter, Adam Wiles, Rodney Wiles, Jacob Kiser, David R. Morcock, Rebecca Shoemaker, Randy Fast, Matthew W. Breed, Joshua Kramer, Duncan Donohue, Tyler Malys, Christine M. Fennessey, Charles M. Trubey, Claire Deleage, Jacob D. Estes, Jeffrey D. Lifson, Brandon F. Keele, Gregory Q. Del Prete
×Abstract
In rheumatoid arthritis (RA), osteoclastic bone resorption causes structural joint damage as well as periarticular and systemic bone loss. Periarticular bone loss is one of the earliest indices of RA, often preceding the onset of clinical symptoms via largely unknown mechanisms. Excessive osteoclastogenesis induced by receptor activator of NF-κB ligand (RANKL) expressed by synovial fibroblasts causes joint erosion, whereas the role of RANKL expressed by lymphocytes in various types of bone damage has yet to be elucidated. In the bone marrow of arthritic mice, we found an increase in the number of RANKL-expressing plasma cells, which displayed an ability to induce osteoclastogenesis in vitro. Genetic ablation of RANKL in B-lineage cells resulted in amelioration of periarticular bone loss, but not of articular erosion or systemic bone loss, in autoimmune arthritis. We also show conclusive evidence for the critical contribution of synovial fibroblast RANKL to joint erosion in collagen-induced arthritis on the arthritogenic DBA/1J background. This study highlights the importance of plasma-cell RANKL in periarticular bone loss in arthritis and provides mechanistic insight into the early manifestation of bone lesion induced by autoimmunity.
Authors
Noriko Komatsu, Stephanie Win, Minglu Yan, Nam Cong-Nhat Huynh, Shinichiro Sawa, Masayuki Tsukasaki, Asuka Terashima, Warunee Pluemsakunthai, George Kollias, Tomoki Nakashima, Hiroshi Takayanagi
×Abstract
Intratumor heterogeneity is an important mediator of poor outcomes in many cancers, including breast cancer. Genetic subclones frequently contribute to this heterogeneity; however, their growth dynamics and interactions remain poorly understood. PIK3CA and HER2 alterations are known to coexist in breast and other cancers. Herein, we present data that describe the ability of oncogenic PIK3CA mutant cells to induce the proliferation of quiescent HER2 mutant cells through a cell contact–mediated mechanism. Interestingly, the HER2 cells proliferated to become the major subclone over PIK3CA counterparts both in vitro and in vivo. Furthermore, this phenotype was observed in both hormone receptor–positive and –negative cell lines, and was dependent on the expression of fibronectin from mutant PIK3CA cells. Analysis of human tumors demonstrated similar HER2:PIK3CA clonal dynamics and fibronectin expression. Our study provides insight into nonrandom subclonal architecture of heterogenous tumors, which may aid the understanding of tumor evolution and inform future strategies for personalized medicine.
Authors
Swathi Karthikeyan, Ian G. Waters, Lauren Dennison, David Chu, Joshua Donaldson, Dong Ho Shin, D. Marc Rosen, Paula I. Gonzalez-Ericsson, Violeta Sanchez, Melinda E. Sanders, Morgan V. Pantone, Riley E. Bergman, Brad A. Davidson, Sarah C. Reed, Daniel J. Zabransky, Karen Cravero, Kelly Kyker-Snowman, Berry Button, Hong Yuen Wong, Paula J. Hurley, Sarah Croessmann, Ben Ho Park
×Abstract
Monocyte homing to the liver and adhesion to the liver sinusoidal endothelial cells (LSECs) are key elements in nonalcoholic steatohepatitis (NASH) pathogenesis. We reported previously that VCAM-1 mediates monocyte adhesion to LSECs. However, the pathogenic role of VCAM-1 in NASH is unclear. Herein, we report that VCAM-1 was a top upregulated adhesion molecule in the NASH mouse liver transcriptome. Open chromatin landscape profiling combined with genome-wide transcriptome analysis showed robust transcriptional upregulation of LSEC VCAM-1 in murine NASH. Moreover, LSEC VCAM-1 expression was significantly increased in human NASH. LSEC VCAM-1 expression was upregulated by palmitate treatment in vitro and reduced with inhibition of the mitogen-activated protein 3 kinase (MAP3K) mixed lineage kinase 3 (MLK3). Likewise, LSEC VCAM-1 expression was reduced in the Mlk3–/– mice with diet-induced NASH. Furthermore, VCAM-1 neutralizing Ab or pharmacological inhibition attenuated diet-induced NASH in mice, mainly via reducing the proinflammatory monocyte hepatic population as examined by mass cytometry by time of flight (CyTOF). Moreover, endothelium-specific Vcam1 knockout mice were also protected against NASH. In summary, lipotoxic stress enhances the expression of LSEC VCAM-1, in part, through MLK3 signaling. Inhibition of VCAM-1 was salutary in murine NASH and might serve as a potential therapeutic strategy for human NASH.
Authors
Kunimaro Furuta, Qianqian Guo, Kevin D. Pavelko, Jeong-Heon Lee, Keith D. Robertson, Yasuhiko Nakao, Jan Melek, Vijay H. Shah, Petra Hirsova, Samar H. Ibrahim
×Abstract
Omega-3 fatty acids from fish oil reduce triglyceride levels in mammals, yet the mechanisms underlying this effect have not been fully clarified, despite the clinical use of omega-3 ethyl esters to treat severe hypertriglyceridemia and reduce cardiovascular disease risk in humans. Here, we identified in bile a class of hypotriglyceridemic omega-3 fatty acid–derived N-acyl taurines (NATs) that, after dietary omega-3 fatty acid supplementation, increased to concentrations similar to those of steroidal bile acids. The biliary docosahexaenoic acid–containing (DHA-containing) NAT C22:6 NAT was increased in human and mouse plasma after dietary omega-3 fatty acid supplementation and potently inhibited intestinal triacylglycerol hydrolysis and lipid absorption. Supporting this observation, genetic elevation of endogenous NAT levels in mice impaired lipid absorption, whereas selective augmentation of C22:6 NAT levels protected against hypertriglyceridemia and fatty liver. When administered pharmacologically, C22:6 NAT accumulated in bile and reduced high-fat diet–induced, but not sucrose-induced, hepatic lipid accumulation in mice, suggesting that C22:6 NAT is a negative feedback mediator that limits excess intestinal lipid absorption. Thus, biliary omega-3 NATs may contribute to the hypotriglyceridemic mechanism of action of fish oil and could influence the design of more potent omega-3 fatty acid–based therapeutics.
Authors
Trisha J. Grevengoed, Samuel A.J. Trammell, Jens S. Svenningsen, Mikhail V. Makarov, Thomas Svava Nielsen, Jens Christian Brings Jacobsen, Jonas T. Treebak, Philip C. Calder, Marie E. Migaud, Benjamin F. Cravatt, Matthew P. Gillum
×Abstract
Multisystem inflammatory syndrome associated with the SARS-CoV-2 pandemic has recently been described in children (MIS-C), partially overlapping with Kawasaki disease (KD). We hypothesized that (a) MIS-C and prepandemic KD cytokine profiles may be unique and justify the clinical differences observed, and (b) SARS-CoV-2–specific immune complexes (ICs) may explain the immunopathology of MIS-C. Seventy-four children were included: 14 with MIS-C, 9 patients positive for SARS-CoV-2 by PCR without MIS-C (COVID), 14 with prepandemic KD, and 37 healthy controls (HCs). Thirty-four circulating cytokines were quantified in pretreatment serum or plasma samples and the presence of circulating SARS-CoV-2 ICs was evaluated in MIS-C patients. Compared with HCs, the MIS-C and KD groups showed most cytokines to be significantly elevated, with IFN-γ–induced response markers (including IFN-γ, IL-18, and IP-10) and inflammatory monocyte activation markers (including MCP-1, IL-1α, and IL-1RA) being the main triggers of inflammation. In linear discriminant analysis, MIS-C and KD profiles overlapped; however, a subgroup of MIS-C patients (MIS-Cplus) differentiated from the remaining MIS-C patients in IFN-γ, IL-18, GM-CSF, RANTES, IP-10, IL-1α, and SDF-1 and incipient signs of macrophage activation syndrome. Circulating SARS-CoV-2 ICs were not detected in MIS-C patients. Our findings suggest a major role for IFN-γ in the pathogenesis of MIS-C, which may be relevant for therapeutic management.
Authors
Ana Esteve-Sole, Jordi Anton, Rosa Maria Pino-Ramirez, Judith Sanchez-Manubens, Victoria Fumadó, Claudia Fortuny, María Rios-Barnes, Joan Sanchez-de-Toledo, Mónica Girona-Alarcón, Juan Manuel Mosquera, Silvia Ricart, Cristian Launes, Mariona Fernández de Sevilla, Cristina Jou, Carmen Muñoz-Almagro, Eva González-Roca, Andrea Vergara, Jorge Carrillo, Manel Juan, Daniel Cuadras, Antoni Noguera-Julian, Iolanda Jordan, Laia Alsina
×Abstract
The immunopathology of coronavirus disease 2019 (COVID-19) remains enigmatic, causing immunodysregulation and T cell lymphopenia. Monocytic myeloid-derived suppressor cells (M-MDSCs) are T cell suppressors that expand in inflammatory conditions, but their role in acute respiratory infections remains unclear. We studied the blood and airways of patients with COVID-19 across disease severities at multiple time points. M-MDSC frequencies were elevated in blood but not in nasopharyngeal or endotracheal aspirates of patients with COVID-19 compared with healthy controls. M-MDSCs isolated from patients with COVID-19 suppressed T cell proliferation and IFN-γ production partly via an arginase 1–dependent (Arg-1–dependent) mechanism. Furthermore, patients showed increased Arg-1 and IL-6 plasma levels. Patients with COVID-19 had fewer T cells and downregulated expression of the CD3ζ chain. Ordinal regression showed that early M-MDSC frequency predicted subsequent disease severity. In conclusion, M-MDSCs expanded in the blood of patients with COVID-19, suppressed T cells, and were strongly associated with disease severity, indicating a role for M-MDSCs in the dysregulated COVID-19 immune response.
Authors
Sara Falck-Jones, Sindhu Vangeti, Meng Yu, Ryan Falck-Jones, Alberto Cagigi, Isabella Badolati, Björn Österberg, Maximilian Julius Lautenbach, Eric Åhlberg, Ang Lin, Rico Lepzien, Inga Szurgot, Klara Lenart, Fredrika Hellgren, Holden Maecker, Jörgen Sälde, Jan Albert, Niclas Johansson, Max Bell, Karin Loré, Anna Färnert, Anna Smed-Sörensen
×Abstract
The effect of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on the pathophysiology of the placenta and its impact on pregnancy outcome has not yet been fully elucidated. Here, we present a comprehensive clinical, morphological, and molecular analysis of placental tissues from pregnant women with and without SARS-CoV-2 infection. SARS-CoV-2 could be detected in half of placental tissues from SARS-CoV-2–positive women. The presence of the virus was not associated with any distinctive pathological, maternal, or neonatal outcome features. SARS-CoV-2 tissue load was low in all but one patient who exhibited severe placental damage leading to neonatal neurological manifestations. The placental transcriptional response induced by high viral load of SARS-CoV-2 showed an immunopathology phenotype similar to autopsy lung tissues from patients with severe coronavirus disease 2019. This finding contrasted with the lack of inflammatory response in placental tissues from SARS-CoV-2–positive women with low viral tissue load and from SARS-CoV-2–negative women. Importantly, no evidence of vertical transmission of SARS-CoV-2 was found in any newborns, suggesting that the placenta may be an effective maternal-neonatal barrier against the virus even in the presence of severe infection. Our observations suggest that severe placental damage induced by the virus may be detrimental for the neonate independently of vertical transmission.
Authors
Fulvia Milena Cribiù, Roberta Erra, Lorenza Pugni, Carlota Rubio-Perez, Lidia Alonso, Sara Simonetti, Giorgio Alberto Croci, Garazi Serna, Andrea Ronchi, Carlo Pietrasanta, Giovanna Lunghi, Anna Maria Fagnani, Maria Piñana, Matthias Matter, Alexandar Tzankov, Luigi Terracciano, Andres Anton, Enrico Ferrazzi, Stefano Ferrero, Enrico Iurlaro, Joan Seoane, Paolo Nuciforo
×Abstract
Hirschsprung disease (HSCR) is the most frequent developmental anomaly of the enteric nervous system, with an incidence of 1 in 5000 live births. Chronic intestinal pseudo-obstruction (CIPO) is less frequent and classified as neurogenic or myogenic. Isolated HSCR has an oligogenic inheritance with RET as the major disease-causing gene, while CIPO is genetically heterogeneous, caused by mutations in smooth muscle–specific genes. Here, we describe a series of patients with developmental disorders including gastrointestinal dysmotility, and investigate the underlying molecular bases. Trio-exome sequencing led to the identification of biallelic variants in ERBB3 and ERBB2 in 8 individuals variably associating HSCR, CIPO, peripheral neuropathy, and arthrogryposis. Thorough gut histology revealed aganglionosis, hypoganglionosis, and intestinal smooth muscle abnormalities. The cell type–specific ErbB3 and ErbB2 function was further analyzed in mouse single-cell RNA sequencing data and in a conditional ErbB3-deficient mouse model, revealing a primary role for ERBB3 in enteric progenitors. The consequences of the identified variants were evaluated using quantitative real-time PCR (RT-qPCR) on patient-derived fibroblasts or immunoblot assays on Neuro-2a cells overexpressing WT or mutant proteins, revealing either decreased expression or altered phosphorylation of the mutant receptors. Our results demonstrate that dysregulation of ERBB3 or ERBB2 leads to a broad spectrum of developmental anomalies, including intestinal dysmotility.
Authors
Thuy-Linh Le, Louise Galmiche, Jonathan Levy, Pim Suwannarat, Debby M.E.I. Hellebrekers, Khomgrit Morarach, Franck Boismoreau, Tom E.J. Theunissen, Mathilde Lefebvre, Anna Pelet, Jelena Martinovic, Antoinette Gelot, Fabien Guimiot, Amanda Calleroz, Cyril Gitiaux, Marie Hully, Olivier Goulet, Christophe Chardot, Severine Drunat, Yline Capri, Christine Bole-Feysot, Patrick Nitschké, Sandra Whalen, Linda Mouthon, Holly E. Babcock, Robert Hofstra, Irenaeus F.M. de Coo, Anne-Claude Tabet, Thierry J. Molina, Boris Keren, Alice Brooks, Hubert J.M. Smeets, Ulrika Marklund, Christopher T. Gordon, Stanislas Lyonnet, Jeanne Amiel, Nadège Bondurand
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ISSN: 0021-9738 (print), 1558-8238 (online)