Although chronic low-grade inflammation does not cause immediate clinical symptoms, over longer term can enhance other insults or of age-dependent damage to organ systems and thereby contribute to age-related disorders, such as respiratory disorders, heart disease, metabolic disorders, autoimmunity, and cancer. However, the molecular mechanisms governing low-level inflammation are largely unknown. We discovered that Bik-deficiency causes low level inflammation even at baseline and the development of spontaneous emphysema in female but not male mice. Similarly, a single nucleotide polymorphism that reduced Bik levels was associated with increased inflammation and enhanced decline in lung function in humans. Transgenic expression of Bik in the airways of Bik-deficient mice inhibited allergen- or LPS-induced lung inflammation and reversed emphysema in female mice. Bik-deficiency increased nuclear but not cytosolic p65 levels, because Bik by modifying the BH4 domain of Bcl-2 interacted with Rpn1 and Rpn2 and enhanced proteasomal degradation of nuclear proteins. Bik-deficiency increased inflammation primarily in females because Bcl-2 and Bik levels were reduced in lung tissues and airway cells of female compared with male mice. Therefore, controlling low-grade inflammation by modifying the unappreciated role of Bik and Bcl-2 in facilitating proteasomal degradation of nuclear proteins may be crucial in treating chronic age-related diseases.
Yohannes A. Mebratu, Jane T. Jones, Congjian Liu, Zerihun H. Negasi, Mizanur Rahman, Joselyn Rojas-Quintero, George T. O'Connor, Wei Gao, Josee Dupuis, Michael H. Cho, Augusto A. Litonjua, Scott Randell, Yohannes Tesfaigzi
Altered tryptophan catabolism has been identified in inflammatory diseases like rheumatoid arthritis (RA) and spondyloarthritis (SpA), but the causal mechanisms linking tryptophan metabolites to disease are unknown. Using the collagen-induced arthritis (CIA) model we identified alterations in tryptophan metabolism, and specifically indole, that correlated with disease. We demonstrated that both bacteria and dietary tryptophan were required for disease, and indole supplementation was sufficient to induce disease in their absence. When mice with CIA on a low-tryptophan diet were supplemented with indole, we observed significant increases in serum IL-6, TNF, and IL-1β; splenic RORγt+CD4+ T cells and ex vivo collagen-stimulated IL-17 production; and a pattern of anti-collagen antibody isotype switching and glycosylation that corresponded with increased complement fixation. IL-23 neutralization reduced disease severity in indole-induced CIA. Finally, exposure of human colon lymphocytes to indole increased expression of genes involved in IL-17 signaling and plasma cell activation. Altogether, we propose a mechanism by which intestinal dysbiosis during inflammatory arthritis results in altered tryptophan catabolism, leading to indole stimulation of arthritis development. Blockade of indole generation may present a unique therapeutic pathway for RA and SpA.
Brenda J. Seymour, Brandon Trent, Brendan E. Allen, Adam J. Berlinberg, Jimmy Tangchittsumran, Widian K. Jubair, Meagan E. Chriswell, Sucai Liu, Alfredo Ornelas, Andrew Stahly, Erica E. Alexeev, Alexander S. Dowdell, Sunny L. Sneed, Sabrina Fechtner, Jennifer M. Kofonow, Charles E. Robertson, Stephanie M. Dillon, Cara C. Wilson, Robert M. Anthony, Daniel N. Frank, Sean P. Colgan, Kristine A. Kuhn
Aplasia cutis congenita (ACC) is a congenital epidermal defect of the midline scalp and has been proposed to be due to a primary keratinocyte abnormality. Why it forms mainly at this anatomic site has remained a longstanding enigma. KCTD1 mutations cause ACC, ectodermal abnormalities, and kidney fibrosis, whereas KCTD15 mutations cause ACC and cardiac outflow tract abnormalities. Here, we find that KCTD1 and KCTD15 can form multimeric complexes and can compensate for each other's loss, and that disease mutations are dominant-negative, resulting in lack of KCTD1/KCTD15 function. We demonstrate that KCTD15 is critical for cardiac outflow tract development, whereas KCTD1 regulates distal nephron function. Combined inactivation of KCTD1/KCTD15 in keratinocytes results in abnormal skin appendages, but not in ACC. Instead, KCTD1/KCTD15 inactivation in neural crest cells results in ACC linked to midline skull defects, demonstrating that ACC is not caused by a primary defect in keratinocytes but is a secondary consequence of impaired cranial neural crest cells giving rise to midline cranial suture cells that express keratinocyte-promoting growth factors. Our findings explain the clinical observations in patients with KCTD1 versus KCTD15 mutations, establish KCTD1/KCTD15 as critical regulators of ectodermal and neural crest cell functions, and define ACC as a neurocristopathy.
Jackelyn R. Raymundo, Hui Zhang, Giovanni Smaldone, Wenjuan Zhu, Kathleen E. Daly, Benjamin J. Glennon, Giovanni Pecoraro, Marco Salvatore, William A. Devine, Cecilia W. Lo, Luigi Vitagliano, Alexander G. Marneros
Itaconate has emerged as a critical immunoregulatory metabolite. Here, we examined the therapeutic potential of itaconate in atherosclerosis. We found that both itaconate and the enzyme that synthesizes it, aconitate decarboxylase 1 (Acod1, also known as “immune-responsive gene 1”/IRG1) are upregulated during atherogenesis in mice. Deletion of Acod1 in myeloid cells exacerbated inflammation and atherosclerosis in vivo and resulted in an elevated frequency of a specific subset of M1-polarized proinflammatory macrophages in the atherosclerotic aorta. Importantly, Acod1 levels were inversely correlated with clinical occlusion in atherosclerotic human aorta specimens. Treating mice with the itaconate derivative 4-ocytyl itaconate attenuated inflammation and atherosclerosis induced by high cholesterol. Mechanistically, we found that the antioxidant transcription factor, Nuclear factor erythroid-2 Related Factor 2 (Nrf2) was required for itaconate to suppress macrophage activation induced by oxidized lipids in vitro and to decrease atherosclerotic lesion areas in vivo. Overall, our work shows that itaconate suppresses atherogenesis by inducing Nrf2-dependent inhibition of proinflammatory responses in macrophages. Activation of the itaconate pathway may represent an important approach to treat atherosclerosis.
Jianrui Song, Yanling Zhang, Ryan A. Frieler, Anthony Andren, Sherri C. Wood, Daniel J. Tyrrell, Peter Sajjakulnukit, Jane C. Deng, Costas A. Lyssiotis, Richard M. Mortensen, Morgan Salmon, Daniel R. Goldstein
Several canonical translocations produce oncofusion genes that can initiate Acute Myeloid Leukemia (AML). Although each translocation is associated with unique features, the mechanisms responsible remain unclear. While proteins interacting with each oncofusion are known to be relevant for how they act, these interactions have not yet been systematically defined. To address this issue in an unbiased fashion, we fused a promiscuous biotin ligase ("TurboID") in-frame with three favorable-risk acute myeloid leukemia (AML) oncofusion cDNAs (PML::RARA, RUNX1::RUNX1T1, and CBFB::MYH11), and identified their interacting proteins in primary murine hematopoietic cells. The PML::RARA- and RUNX1::RUNX1T1-TurboID fusion proteins labeled common and unique nuclear repressor complexes, implying their nuclear localization. However, CBFB::MYH11-TurboID interacting proteins were largely cytoplasmic, probably due to an interaction of the MYH11 domain with several cytoplasmic myosin-related proteins. Using a variety of methods, we showed that the CBFB domain of CBFB::MYH11 sequesters RUNX1 in cytoplasmic aggregates; these findings were confirmed in primary human AML cells. Paradoxically, CBFB::MYH11 expression was associated with increased RUNX1/2 expression, suggesting the presence of a sensor for reduced functional RUNX1 protein, and a feedback loop that that may attempt to compensate by increasing RUNX1/2 transcription. These findings may have broad implications for AML pathogenesis.
Ryan B. Day, Julia A. Hickman, Ziheng Xu, Casey D.S. Katerndahl, Francesca Ferraro, Sai Mukund Ramakrishnan, Petra Erdmann-Gilmore, Robert W. Sprung, Yiling Mi, R. Reid Townsend, Christopher A. Miller, Timothy J. Ley
Non-alcoholic fatty liver disease (NAFLD) is prevalent in the majority of obese individuals, but in a subset, this progresses to non-alcoholic steatohepatitis (NASH) and fibrosis. The mechanisms that prevent NASH and fibrosis in the majority of NAFLD patients remain unclear. Here we report that NAD(P)H oxidase (NOX)-4 and nuclear factor erythroid 2-related factor 2 (NFE2L2) were elevated in hepatocytes early in disease progression to prevent NASH/fibrosis. Mitochondrial-derived reactive oxygen species (ROS) activated NFE2L2 to induce the expression of NOX4, which in turn generated H2O2 to exacerbate the NFE2L2 antioxidant defense response. The deletion or inhibition of NOX4 in hepatocytes decreased ROS and attenuated antioxidant defense to promote mitochondrial oxidative stress, damage proteins and lipids, diminish insulin signalling and promote cell death upon oxidant challenge. Hepatocyte NOX4 deletion in high fat fed obese mice, which otherwise develop steatosis, but not NASH, resulted in hepatic oxidative damage, inflammation and T cell recruitment to drive NASH and fibrosis, whereas NOX4 overexpression tempered the development of NASH/fibrosis in mice fed a NASH-promoting diet. Thus, mitochondrial- and NOX4-derived ROS function in concert to drive a NFE2L2 antioxidant defense response to attenuate oxidative liver damage and the progression to NASH/fibrosis in obesity.
Spencer Greatorex, Supreet Kaur, Chrysovalantou E. Xirouchaki, Pei Kee Goh, Florian Wiede, Amanda J. Genders, Melanie Tran, YaoYao Jia, Arthe Raajendiran, Wendy A. Brown, Catriona A. McLean, Junichi Sadoshima, Matthew J. Watt, Tony Tiganis
Microscopic hemorrhage is a common aspect of cancers, yet its potential role as an independent factor influencing both cancer progression and therapeutic response is largely ignored. Recognizing the essential function of macrophages in red blood cell disposal, we explored a pathway that connects intratumoral hemorrhage with the formation of cancer-promoting tumor-associated macrophages (TAMs). Using spatial transcriptomics, we found that NRF2-activated myeloid cells possessing characteristics of procancerous TAMs tend to cluster in peri-necrotic hemorrhagic tumor regions. These cells resembled anti-inflammatory erythrophagocytic macrophages. We identified heme, a red blood cell metabolite, as a pivotal microenvironmental factor steering macrophages toward protumorigenic activities. Single-cell RNA-seq and functional assays of TAMs in 3D cell culture spheroids revealed how elevated intracellular heme signals via the transcription factor NRF2 to induce cancer-promoting TAMs. These TAMs stabilized epithelial-mesenchymal transition, enhancing cancer invasiveness and metastatic potential. Additionally, NRF2-activated macrophages exhibited resistance to reprogramming by IFNγ and anti-CD40 antibodies, reducing their tumoricidal capacity. Furthermore, MC38 colon adenocarcinoma-bearing mice with NRF2 constitutively activated in leukocytes were resistant to anti-CD40 immunotherapy. Overall, our findings emphasize hemorrhage-activated NRF2 in TAMs as a driver of cancer progression, suggesting that targeting this pathway could offer new strategies to enhance cancer immunity and overcome therapy resistance.
Dominik J. Schaer, Nadja Schulthess-Lutz, Livio Baselgia, Kerstin Hansen, Raphael M. Buzzi, Rok Humar, Elena Dürst, Florence Vallelian
Acute myeloid leukemia (AML) presents a pressing medical need in that it is largely resistant to standard chemotherapy as well as modern therapeutics such as targeted therapy and immunotherapy, including anti-PD therapy. We demonstrate that Programmed Death-1 Homolog (PD-1H), an immune co-inhibitory molecule is highly expressed in blasts from the bone marrow of AML patients, while normal myeloid cell subsets and T cells have the expression of PD-1H. In studies employing syngeneic and humanized AML mouse models, overexpression of PD-1H promoted the growth of AML cells, mainly by evading T cell-mediated immune responses. Importantly, ablation of AML cell surface PD-1H by antibody blockade or genetic targeting significantly inhibited AML progression by promoting T cell activity. In addition, the genetic deletion of PD-1H from host normal myeloid cells inhibited AML progression as well and the combination of PD-1H blockade with PD-1 blockade conferred a synergistic anti-leukemia effect. Our findings provide the basis for PD-1H as an attractive therapeutic target to treat human AML.
Tae Kon Kim, Xue Han, Qianni Hu, Esten N. Vandsemb, Carly M. Fielder, Junshik Hong, Kwang Woon Kim, Emily F. Mason, R. Skipper Plowman, Jun Wang, Qi Wang, Jian-Ping Zhang, Ti Badri, Miguel F. Sanmamed, Linghua Zheng, Tianxiang Zhang, Jude Alawa, Sang Won Lee, Amer M. Zeidan, Stephanie Halene, Manoj M. Pillai, Namrata S. Chandhok, Jun Lu, Mina L. Xu, Steven D. Gore, Lieping Chen
Platelets from patients with myeloproliferative neoplasms (MPNs) exhibit a hyperreactive phenotype. Here, we found elevated P-selectin exposure and platelet-leukocyte aggregates indicating activation of platelets from essential thrombocythemia (ET) patients. Single cell RNA-seq analysis of primary samples revealed significant enrichment of transcripts related to platelet activation, mTOR and oxidative phosphorylation (OXPHOS) in ET patient platelets. These observations were validated via proteomic profiling. Platelet metabolomics revealed distinct metabolic phenotypes consisting of elevated ATP generation, accompanied by increases in the levels of multiple intermediates of the tricarboxylic acid (TCA) cycle, but lower alpha-ketoglutarate (α-KG) in MPN patients. Inhibition of PI3K/AKT/mTOR signaling significantly reduced metabolic responses and hyperreactivity in MPN patient platelets, while α-KG supplementation markedly reduced oxygen consumption and ATP generation. Ex vivo incubation of platelets from both MPN patients and Jak2 V617F mice with α-KG significantly reduced platelet activation responses. Oral α-KG supplementation of Jak2 V617F mice decreased splenomegaly and reduced hematocrit, monocyte and platelet counts. Finally, α-KG incubation significantly decreased proinflammatory cytokine secretion from MPN CD14+ monocytes. Our results reveal a previously unrecognized metabolic disorder in conjunction with aberrant PI3K/AKT/mTOR signaling, contributing to platelet hyperreactivity in MPN patients.
Fan He, Angelo B.A. Laranjeira, Tim Kong, Shuyang Lin, Katrina J. Ashworth, Alice Liu, Nina M. Lasky, Daniel A.C. Fisher, Maggie J. Cox, Mary C. Fulbright, Lilian A. Antunes Heck, LaYow C. Yu, Molly Brakhane, Bei Gao, Stephen M. Sykes, Angelo D’Alessandro, Jorge A. Di Paola, Stephen T. Oh
Hidradenitis suppurativa (HS) is a chronic inflammatory disease characterized by abscesses, nodules, dissecting/draining tunnels, and extensive fibrosis. Here, we integrate single-cell RNA sequencing, spatial transcriptomics, and immunostaining to provide an unprecedented view of the pathogenesis of chronic HS, characterizing the main cellular players, and defining their interactions. We describe a striking layering of the chronic HS infiltrate and identify the contribution of two fibroblast subtypes (SFRP4+ and CXCL13+) in orchestrating this compartmentalized immune response. We further demonstrate the central role of the Hippo pathway in promoting extensive fibrosis in HS and provide pre-clinical evidence that the pro-fibrotic fibroblast response in HS can be modulated through inhibition of this pathway. These data provide novel insights into key aspects of HS pathogenesis with broad therapeutic implications.
Kelsey R. van Straalen, Feiyang Ma, Pei-Suen Tsou, Olesya Plazyo, Mehrnaz Gharaee-Kermani, Marta Calbet, Xianying Xing, Mrinal K. Sarkar, Ranjitha Uppala, Paul W. Harms, Rachael Wasikowski, Lina Nahlawi, Mio Nakamura, Milad Eshaq, Cong Wang, Craig J. Dobry, Jeffrey H. Kozlow, Jill R. Cherry-Bukowiec, William D. Brodie, Kerstin Wolk, Özge Uluckan, Megan N. Mattichak, Matteo Pellegrini, Robert L. Modlin, Emanual Maverakis, Robert Sabat, J. Michelle Kahlenberg, Allison C. Billi, Lam C. Tsoi, Johann E. Gudjonsson
Challenging skeletal repairs are frequently seen in patients experiencing systemic inflammation. To tackle the complexity and heterogeneity of skeletal repair process, we performed single-cell RNA sequencing and revealed that progenitor cell was one of the major lineages responsive to elevated inflammation and this response adversely affected progenitor differentiation by upregulation of Rbpjk in fracture nonunion. We then validated the interplay between inflammation (via Ikk2ca) and Rbpjk specifically in progenitors by using genetic animal models. Focusing on epigenetic regulation, we identified Rbpjk as a direct target of Dnmt3b. Mechanistically, inflammation decreased Dnmt3b expression in progenitor cells, consequently leading to Rbpjk upregulation via hypomethylation within its promoter region. We also showed that Dnmt3b loss-of-function mice phenotypically recapitulated the fracture repair defects observed in Ikk2ca mice, whereas Dnmt3b transgenic mice alleviated fracture repair defects induced by Ikk2ca. Moreover, Rbpjk ablation restored fracture repair in both Ikk2ca mice and Dnmt3b loss-of-function mice. Altogether, this work elucidates a common mechanism involving NFkB/Dnmt3b/Rbpjk axis within the context of inflamed bone regeneration. Building upon this mechanistic insight, we applied local treatment with epigenetically modified progenitor cells in RA mice and showed a functional restoration of bone regeneration under inflammatory condition through an increase in progenitor differentiation potential.
Ding Xiao, Liang Fang, Zhongting Liu, Yonghua He, Jun Ying, Haocheng Qin, Aiwu Lu, Meng Shi, Tiandao Li, Bo Zhang, Jianjun Guan, Cuicui Wang, Yousef Abu-Amer, Jie Shen
Worldwide, over 800 million people are affected by kidney disease, yet its pathogenesis remains elusive, hindering the development of novel therapeutics. In this study, we employed kidney-specific expression of quantitative traits and single-nuclear open chromatin analysis to show that genetic variants linked to kidney dysfunction on chromosome 20 target the acyl-CoA synthetase short-chain family 2 (ACSS2). By generating ACSS2 knock-out mice, we demonstrated their protection from kidney fibrosis in multiple disease models. Our analysis of primary tubular cells revealed that ACSS2 regulates de novo lipogenesis (DNL), causing NADPH depletion and increasing ROS levels, ultimately leading to NLRP3-dependent pyroptosis. Additionally, we discovered that pharmacological inhibition or genetic ablation of fatty acid synthase safeguarded kidney cells against profibrotic gene expression and prevented kidney disease in mice. Lipid accumulation and the expression of genes related to DNL were elevated in the kidneys of patients with fibrosis. Our findings pinpoint ACSS2 as a critical kidney disease gene and reveal the role of DNL in kidney disease.
Dhanunjay Mukhi, Lingzhi Li, Hongbo Liu, Tomohito Doke, Lakshmi P. Kolligundla, Eunji Ha, Konstantin A. Klötzer, Amin Abedini, Sarmistha Mukherjee, Junnan Wu, Poonam Dhillon, Hailong Hu, Dongyin Guan, Katsuhiko Funai, Kahealani Uehara, Paul M. Titchenell, Joseph A. Baur, Kathryn E. Wellen, Katalin Susztak
About 25% of people within the general population are insulin resistant, increasing the risk for type 2 diabetes (T2D) and metabolic disease. Transcriptomic analysis of iPS cells differentiated into myoblasts (iMyos) from insulin resistant (I-Res) versus insulin sensitive (I-Sen) non-diabetic individuals reveals 306 genes increased and 271 genes decreased in expression in iMyos from insulin resistant donors with differences of 2-folds or more. Over 30 of the genes changed in I-Res iMyos are associated with T2D by SNP polymorphisms and functionally linked to insulin action and control of metabolism. Interestingly, we also identified >1500 differences in gene expression that were dependent on sex of the cell donor, some of which modified the insulin resistance effects. Many of these sex-differences were associated with increased DNA methylation in cells from females and reversed by 5-azacytidine. By contrast, the insulin sensitivity differences were not reversed and thus appear to reflect genetic or methylation-independent epigenetic effects.
Nida Haider, C. Ronald Kahn
Pancreatic beta-cells are specialized for coupling glucose metabolism to insulin peptide production and secretion. Acute glucose exposure robustly and coordinately increases translation of proinsulin and proteins required for secretion of mature insulin peptide. By contrast, chronically elevated glucose levels that occur during diabetes impair beta-cell insulin secretion and have been shown experimentally to suppress insulin translation. Whether translation of other genes critical for insulin secretion are similarly downregulated by chronic high glucose is unknown. Here, we used high-throughput ribosome profiling and nascent proteomics in MIN6 insulinoma cells to elucidate the genome-wide impact of sustained high glucose on beta-cell mRNA translation. Prior to induction of ER stress or suppression of global translation, sustained high glucose suppressed glucose-stimulated insulin secretion and downregulated translation of not only insulin, but also of mRNAs related to insulin secretory granule formation, exocytosis, and metabolism-coupled insulin secretion. Translation of these mRNAs was also downregulated in primary rat and human islets following ex-vivo incubation with sustained high glucose and in an in vivo model of chronic mild hyperglycemia. Furthermore, translational downregulation decreased cellular abundance of these proteins. Our study uncovered a translational regulatory circuit during beta-cell glucose toxicity that impairs expression of proteins with critical roles in beta-cell function.
Abigael Cheruiyot, Jennifer Hollister-Lock, Brooke A. Sullivan, Hui Pan, Jonathan M. Dreyfuss, Susan Bonner-Weir, Jean E. Schaffer
The study investigates a mechanistic link if bacterial biofilm mediated host-pathogen interaction leads to immunological complications associated with breast implant illness (BII). Over 10 million women worldwide have breast implants. In recent years, women have described a constellation of immunological symptoms believed to be related to their breast implants. The study included 178 subjects divided in three cohorts. Eighty-six patients reported symptoms consistent with BII. Control group I (non-BII, N=55) included patients with breast implants without BII symptoms but went through explantation of the breast implant. Control group II (normal tissue, N=37) was comprised of women without an implant, whose breast tissue was removed as an unrelated clinically indicated surgical procedures. We report that periprosthetic breast tissue of BII had increased abundance of biofilm and biofilm-derived oxylipin, 10-HOME. S. epidermidis biofilm was observed to be higher in the BII group (73.33%) compared to non-BII group (16.67%, p=0.018) and the normal group (10%, p=0.036). The oxylipin was found to be immunogenic capable of polarizing naïve CD4+ T cells with a resulting Th1 subtype in vitro and in vivo. Consistently, an abundance of CD4+Th1 subtype was observed in the periprosthetic breast tissue and blood of BII subjects. Mice injected with 10-HOME also had increased Th1 subtype in blood akin to BII patients and demonstrated fatigue-like symptoms. The identification of an oxylipin-mediated mechanism of immune activation induced by local bacterial biofilm associated with BII provides insight into the possible pathogenesis of implant-associated immune symptoms of BII.
Imran Khan, Robert E. Minto, Christine Kelley-Patteson, Kanhaiya Singh, Lava Timsina, Lily J. Suh, Ethan Rinne, Bruce W. Van Natta, Colby R. Neumann, Ganesh Mohan, Mary Lester, R. Jason VonDerHaar, Rana German, Natascia Marino, Aladdin H. Hassanein, Gayle M. Gordillo, Mark H. Kaplan, Chandan K. Sen, Marshall E. Kadin, Mithun Sinha
Current treatments for neurodegenerative diseases and neural injuries face major challenges, primarily due to the diminished regenerative capacity of neurons in the mammalian central nervous system (CNS) as they mature. Here, we investigated the role of Ezh2, a histone methyltransferase, in regulating mammalian axon regeneration. We found that Ezh2 declined in the mouse nervous system during maturation but was upregulated in adult dorsal root ganglion neurons following peripheral nerve injury to facilitate spontaneous axon regeneration. In addition, overexpression of Ezh2 in retinal ganglion cells in the CNS promoted optic nerve regeneration via both histone methylation-dependent and -independent mechanisms. Further investigation revealed that Ezh2 fostered axon regeneration by orchestrating the transcriptional silencing of genes governing synaptic function and those inhibiting axon regeneration, while concurrently activating various factors that support axon regeneration. Notably, we demonstrated that GABA transporter 2 encoded by Slc6a13 acted downstream of Ezh2 to control axon regeneration. Overall, our study underscores the potential of modulating chromatin accessibility as a promising strategy for promoting CNS axon regeneration.
Xue-Wei Wang, Shu-Guang Yang, Ming-Wen Hu, Rui-Ying Wang, Chi Zhang, Anish R. Kosanam, Arinze J. Ochuba, Jing-Jing Jiang, Ximei Luo, Yun Guan, Jiang Qian, Chang-Mei Liu, Feng-Quan Zhou
Blood–brain barrier (BBB) disruption is a serious pathological consequence of traumatic brain injury (TBI), for which there are limited therapeutic strategies. Tissue inhibitor of metalloproteinase-2 (TIMP2), a molecule with dual functions of inhibiting matrix metalloproteinase (MMP) activity and displaying cytokine-like activity through receptor binding, has been reported to inhibit VEGF-induced vascular hyperpermeability. Here, we investigate the ability of TIMP2 to ameliorate BBB disruption in TBI and the underlying molecular mechanisms. Both TIMP2 and AlaTIMP2, a TIMP2 mutant without MMP-inhibiting activity, attenuated neurological deficits and BBB leakage in TBI mice, as well as inhibited junctional protein degradation and translocation to reduce paracellular permeability in HBMECs exposed to hypoxic plus inflammatory insult. Mechanistic studies revealed that TIMP2 interacted with integrin α3β1 on endothelial cells (ECs), inhibiting Src activation-dependent VE-Cadherin phosphorylation, VE-Cadherin/catenin complex destabilization and subsequent VE-Cadherin internalization. Notably, localization of VE-Cadherin on the membrane was critical for TIMP2-mediated EC barrier integrity. Furthermore, TIMP2-mediated increased membrane localization of VE-Cadherin enhanced the level of active Rac1, thereby inhibiting stress fiber formation. Together, our studies have identified an MMP-independent mechanism by which TIMP2 regulates EC barrier integrity after TBI. TIMP2 may be a therapeutic agent for TBI and other neurological disorders involving BBB breakdown.
Jingshu Tang, Yuying Kang, Yujun Zhou, Nianying Shang, Xinnan Li, Hongyue Wang, Jiaqi Lan, Shuai Wang, Lei Wu, Ying Peng
Vascular aging impacts multiple organ systems, including the brain, where it can lead to vascular dementia. However, a concrete understanding of how aging specifically affects the brain vasculature, along with molecular read-outs, remain vastly incomplete. Here we demonstrate that aging is associated with a marked decline in Notch3 signaling in both murine and human brain vessels. To clarify the consequences of Notch3 loss in the brain vasculature, we used single-cell transcriptomics and uncovered that Notch3 inactivation alters regulation of calcium, contractile function, and promotes a notable increase in extracellular matrix. These alterations adversely impact vascular reactivity, manifesting as dilation, tortuosity, microaneurysms, and decreased cerebral blood flow, as observed by MRI. Combined, these vascular impairments hinder glymphatic flow and result in buildup of glycosaminoglycans within the brain parenchyma. Remarkably, this phenomenon mirrors a key pathological feature found in brains of CADASIL patients – a hereditary vascular dementia associated with NOTCH3 missense mutations. Additionally, single-cell RNA sequencing of the neuronal compartment in aging Notch3 null mice has unveiled patterns reminiscent of those observed in neurodegenerative diseases. These findings offer direct evidence that age-related NOTCH3 deficiencies trigger a progressive decline in vascular function, subsequently affecting glymphatic flow and culminating in neurodegeneration.
Milagros C. Romay, Russell H. Knutsen, Feiyang Ma, Ana Mompeón, Gloria E. Hernandez, Jocelynda Salvador, Snezana Mirkov, Ayush Batra, David P. Sullivan, Daniele Procissi, Samuel Buchanan, Elise Kronquist, Elisa A. Ferrante, William A. Muller, Jordain Walshon, Alicia Steffens, Kathleen McCortney, Craig Horbinski, Elisabeth Tournier‑Lasserve, Adam M. Sonabend, Farzaneh A. Sorond, MichaelM. Wang, Manfred Boehm, Beth A. Kozel, M. Luisa Iruela-Arispe
C1q/TNF related protein 4 (CTRP4) is generally thought to be released extracellularly and plays a critical role in energy metabolism and protecting against sepsis. However, its physiological functions in autoimmune diseases have not been thoroughly explored. In this study, we demonstrated that Th17 cell-associated experimental autoimmune encephalomyelitis was greatly exacerbated in Ctrp4-/- mice compared to WT mice due to increased Th17 cell infiltration. The absence of Ctrp4 promoted the differentiation of naïve CD4+ T cells into Th17 cells in vitro. Mechanistically, CTRP4 interferes with the interaction between IL-6 and IL-6R by directly competing to bind with IL-6R leading to suppression of IL-6-induced activation of STAT3 pathway. Furthermore, the administration of recombinant CTRP4 protein ameliorated the disease symptoms. In conclusion, our results indicate that CTRP4, as an endogenous regulator of the IL-6 receptor signaling pathway, may be a potential therapeutic intervention for Th17 driven-autoimmune diseases.
Lulu Cao, Jinhai Deng, Wei Chen, Minwei He, Ning Zhao, He Huang, Lu Ling, Qi Li, Xiaoxin Zhu, Lu Wang
Glycogen storage disease type III (GSDIII) is a rare inborn error of metabolism affecting liver, skeletal muscle, and heart due to mutations of the AGL gene encoding for the glycogen debranching enzyme (GDE). No curative treatment exists for GSDIII. The 4.6 kb GDE cDNA represents the major technical challenge toward the development of a single recombinant adeno-associated virus (rAAV)-derived vector gene therapy strategy. Using information on GDE structure and molecular modeling, we generated multiple truncated GDEs retaining activity. Among them, an N-terminal-truncated mutant ∆Nter2-GDE had a similar efficacy in vivo compared to the full-size enzyme. A rAAV vector expressing ∆Nter2-GDE allowed significant glycogen reduction in heart and muscle of Agl–/– mice three months after intravenous injection, as well as normalization of histology features and restoration of muscle strength. Similarly, glycogen accumulation and histological features were corrected in a recently generated Agl–/– rat model. Finally, transduction with rAAV vectors encoding ∆Nter2-GDE corrected glycogen accumulation in an in vitro human skeletal muscle cellular model of GSDIII. In conclusion, our results demonstrated the ability of a single rAAV vector expressing a functional mini-GDE transgene to correct the muscle and heart phenotype in multiple models of GSDIII, supporting its clinical translation to GSDIII patients.
Antoine Gardin, Jérémy Rouillon, Valle Montalvo-Romeral, Lucille Rossiaud, Patrice Vidal, Romain Launay, Mallaury Vie, Youssef Krimi Benchekroun, Jérémie Cosette, Bérangère Bertin, Tiziana La Bella, Guillaume Dubreuil, Justine Nozi, Louisa Jauze, Romain Fragnoud, Nathalie F. Daniele, Laetitia Van Wittenberghe, Jérémy Esque, Isabelle André, Xavier Nissan, Lucile Hoch, Giuseppe Ronzitti