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Abstract
Sarcomeric disarray is a hallmark of gene mutations in patients with Hypertrophic Cardiomyopathy (HCM). However, it is unknown when detrimental sarcomeric changes first occur and whether they originate in the developing embryonic heart. Furthermore, Rho Kinase (ROCK) is a serine threonine protein kinase that is critical for regulating the function of several sarcomeric proteins and therefore, our aim was to determine if disruption of ROCK signalling during the earliest stages of heart development would disrupt the integrity of sarcomeres altering heart development and function. Using a mouse model in which the function of ROCK is specifically disrupted in embryonic cardiomyocytes we demonstrate a progressive cardiomyopathy that first appeared as sarcomeric disarray during cardiogenesis. This led to abnormalities in the structure of embryonic ventricular wall and compensatory cardiomyocyte hypertrophy during foetal development. This sarcomeric disruption and hypertrophy persisted throughout adult life, triggering left ventricular concentric hypertrophy with systolic dysfunction, and re-activation of foetal gene expression and cardiac fibrosis, all typical features of HCM. Taken together, our findings establish a novel mechanism for the developmental origin of the sarcomeric phenotype of HCM and suggest that variants in the ROCK genes or disruption of ROCK signalling could, in part, contribute to its pathogenesis.
Authors
Kate E. Bailey, Guy A. MacGowan, Simon Tual-Chalot, Lauren Phillips, Tim J. Mohun, Deborah J. Henderson, Helen M. Arthur, Simon D. Bamforth, Helen M. Phillips
Abstract
Anthracyclines are amongst the most effective chemotherapeutics ever developed, but they produce grueling side-effects, serious adverse events and resistance often develops over time. We found that these compounds can be sequestered by secreted cellular Prion protein (PrPC), blocking their cytotoxic activity. This effect was dose-dependent using either cell line-conditioned medium or human serum as a source of PrPC. Genetic depletion of PrPC or inhibition of binding via chelation of ionic copper prevented the interaction and restored cytotoxic activity. This was more pronounced for doxorubicin than its epimer, epirubicin. Investigating the relevance to breast cancer management, we found that the levels of PRNP transcript in pre-treatment tumor biopsies stratified relapse-free survival after neoadjuvant treatment with anthracyclines, particularly amongst doxorubicin-treated patients with residual disease at surgery (p=2.8E-08). These data suggest that local sequestration could mediate treatment resistance. Consistent with this, tumor cell expression of PrPC protein correlated with poorer response to doxorubicin but not epirubicin in an independent cohort analyzed by immunohistochemistry, particularly soluble isoforms released into the extracellular environment by shedding (p=0.015). These findings have important potential clinical implications for frontline regimen decision-making. We suggest there is warranted utility for prognostic PrPC/PRNP assays to guide chemo-sensitization strategies that exploit an understanding of PrPC-anthracycline-copper ion complexes.
Authors
Adrian P. Wiegmans, Jodi M. Saunus, Sunyoung Ham, Richard J. Lobb, Jamie R. Kutasovic, Andrew J. Dalley, Mariska Miranda, Caroline Atkinson, Simote T. Foliaki, Kaltin Ferguson, Colleen Niland, Cameron N. Johnstone, Victoria Lewis, Steven Collins, Sunil R. Lakhani, Fares Al-Ejeh, Andreas Möller
Abstract
Peripheral hyperinsulinemia resulting from subcutaneous insulin injection is associated with metabolic defects which include abnormal glucose metabolism. The first aim of this study was to quantify the impairments in liver and muscle glucose metabolism that occur when insulin is delivered via a peripheral vein compared to when it is given through its endogenous secretory route (the hepatic portal vein) in overnight fasted conscious dogs. The second aim was to determine if peripheral delivery of a hepato-preferential insulin analog could restore the physiologic response to insulin that occurs under meal feeding conditions. This study is the first to show that hepatic glucose uptake correlates with insulin’s direct effects on the liver under hyperinsulinemic-hyperglycemic conditions. In addition, glucose uptake was equally divided between the liver and muscle when insulin was infused into the portal vein, but when it was delivered into a peripheral vein the percentage of glucose taken up by muscle was 4-times greater than that going to the liver, with liver glucose uptake being less than half of normal. These defects could not be corrected by adjusting the dose of peripheral insulin. On the other hand, hepatic and non-hepatic glucose metabolism could be fully normalized by a hepato-preferential insulin analog.
Authors
Dale S. Edgerton, Melanie Scott, Ben Farmer, Phillip E. Williams, Peter Madsen, Thomas Kjeldsen, Christian L. Brand, Christian Fledelius, Erica Nishimura, Alan D. Cherrington
Abstract
Bariatric surgeries including vertical sleeve gastrectomy (VSG) ameliorate obesity and diabetes. Weight-loss and accompanying increases to insulin sensitivity contribute to improved glycemia after surgery, however, studies in humans also suggest weight-independent actions of bariatric procedures to lower blood glucose, possibly by improving insulin secretion. To evaluate this hypothesis, we compared VSG operated mice with pair-fed, sham-surgical controls (PF-Sham) 2 weeks after surgery. This paradigm yielded similar post-operative body weight and insulin sensitivity between VSG and calorically restricted PF-Sham animals. However, VSG improved glucose tolerance and markedly enhanced insulin secretion during oral nutrient and intraperitoneal glucose challenges compared to controls. Islets from VSG mice displayed a unique transcriptional signature enriched for genes involved in Ca2+ signaling and insulin secretion pathways. This finding suggests that bariatric surgery leads to intrinsic changes within the islet that alter function. Indeed, islets isolated from VSG mice had increased glucose-stimulated insulin secretion and a left-shifted glucose sensitivity curve compared to islets from PF-Sham mice. Isolated islets from VSG animals showed corresponding increases in the pulse duration of glucose-stimulated Ca2+ oscillations. Together these findings demonstrate a weight-independent improvement in glycemic control following VSG, which is, in part, driven by improved insulin secretion and associated with substantial changes in islet gene expression. These results support a model in which β-cells play a key role in the adaptation to bariatric surgery and the improved glucose tolerance that is typical of these procedures.
Authors
Jonathan D. Douros, Jingjing Niu, Sophia M. Sdao, Trillian Gregg, Kelsey H. Fisher-Wellman, Manish S. Bharadwaj, Anthony Molina, Ramamani Arumugam, Mackenzie D. Martin, Enrico Petretto, Matthew J. Merrins, Mark A. Herman, Jenny Tong, Jonathan E. Campbell, David D'Alessio
Abstract
The auto antigen (Ag)-specific regulatory T cells (Tregs) from pluripotent stem cells (PSCs), i.e., PSC-Tregs, have the ability to suppress autoimmunity. PSC-Tregs can be programmed to be tissue-associated and to infiltrate into local inflamed tissues to suppress autoimmune responses after adoptive transfer. Nevertheless, the mechanisms by which the auto Ag-specific PSC-Tregs suppress the autoimmune response remain to be fully elucidated. In this study, we generated the functional auto Ag-specific Tregs from the induced PSC (iPSCs), i.e., iPSC-Tregs, and investigated the underlying mechanisms of autoimmunity suppression by these Tregs in a type 1 diabetes (T1D) murine model. A double transgenic (Tg) mouse model of T1D was established in F1 mice in which the first generation of RIP-mOVA Tg mice that were crossed with OT-I T cell receptor (TCR) Tg mice was challenged with vaccinia viruses expressing OVA (VACV-OVA). We show that adoptive transfer of OVA-specific iPSC-Tregs greatly suppressed autoimmunity in the animal model and prevented the insulin-secreting pancreatic β cells from destruction. Further, we demonstrate that the adoptive transfer significantly reduced the expression of ICAM-1 in the diabetic pancreas and inhibited the migration of pathogenic CD8+ T cells and the production of the pro-inflammatory IFN-γ in the pancreas. These results indicate that the stem cell-derived tissue-associated Tregs can robustly accumulate in the diabetic pancreas, and through down-regulating the expression of ICAM-1 in the local inflamed tissues and inhibiting the production of pro-inflammatory cytokine IFN-γ, suppress the migration and activity of the pathogenic immune cells that cause T1D.
Authors
Mohammad Haque, Fengyang Lei, Xiaofang Xiong, Jugal Kishore Das, Xingcong Ren, Deyu Fang, Shahram Salek-Ardakani, Jin-Ming Yang, Jianxun Song
Abstract
Glioblastoma represent universally lethal cancers, containing stem cell-like glioblastoma stem cells (GSCs). While neural stem cells (NSCs) are usually quiescent, single-cell studies suggest that proliferating glioblastoma cells reside in the GSC population. Interrogating in silico glioma databases for epigenetic regulators that correlate with cell cycle regulation, we identified the chromatin remodeler, HELLS, as a potential target in glioblastoma. GSCs preferentially expressed HELLS compared to their differentiated tumor progeny and non-malignant brain cells. Targeting HELLS disrupted GSC proliferation, survival, and self-renewal with induction of replication stress and DNA damage. Investigating potential molecular mechanisms downstream of HELLS revealed that HELLS interacted with the core oncogenic transcription factors, E2F3 and MYC, to regulate gene expression critical to GSC proliferation and maintenance. Supporting the interaction, HELLS expression strongly correlated with targets of E2F3 and MYC transcriptional activity in glioblastoma patients. Potential clinical significance of HELLS was reinforced by improved survival of tumor-bearing mice upon targeting HELLS and poor prognosis of glioma patients with elevated HELLS expression. Collectively, targeting HELLS may permit the functional disruption of the relatively undruggable MYC and E2F3 transcription factors and serve as a novel therapeutic paradigm for glioblastoma.
Authors
Guoxin Zhang, Zhen Dong, Briana C. Prager, Leo J. Y. Kim, Qiulian Wu, Ryan C. Gimple, Xiuxing Wang, Shideng Bao, Petra Hamerlik, Jeremy N. Rich
Abstract
Iron deficiency is present in approximately 50% of heart failure (HF) patients. Large multi-center trials have shown that treatment of iron deficiency with intravenous iron benefits HF patients, but the underlying mechanisms are not known. To investigate the actions of iron deficiency on the heart, mice were fed an iron-depleted diet and some received intravenous ferric carboxymaltose (FCM), an iron supplementation used clinically. Iron-deficient animals became anemic and had reduced ventricular ejection fraction measured by magnetic resonance imaging. Ca2+ signaling, a pathway linked to the contractile deficit in failing hearts, was also significantly affected. Ventricular myocytes isolated from iron-deficient animals produced smaller Ca2+ transients from an elevated diastolic baseline, but had unchanged sarcoplasmic reticulum (SR) Ca2+-load, trigger L-type Ca2+ current or cytoplasmic Ca2+ buffering. Reduced fractional release from the SR was due to downregulated RyR2 channels, detected at protein and message level. The constancy of diastolic SR Ca2+-load is explained by reduced RyR2 permeability in combination with right-shifted SERCA activity due dephosphorylation of its regulator phospholamban. Supplementing iron levels with FCM restored normal Ca2+ signaling and ejection fraction. Thus, two Ca2+-handling proteins previously implicated in HF become functionally impaired in iron-deficiency anemia, but their activity is rescued by intravenous iron supplementation.
Authors
Yu Jin Chung, Antao Luo, Kyung Chan Park, Aminah Loonat, Samira Lakhal-Littleton, Peter A. Robbins, Pawel Swietach
Abstract
Acute respiratory distress syndrome is an often fatal disease that develops after acute lung injury and trauma. How released tissue damage signals, or alarmins, orchestrate early inflammatory events is poorly understood. Herein we reveal that IL-33, an alarmin sequestered in the lung epithelium, is required to limit inflammation after injury due to an unappreciated capacity to mediate Foxp3+ Treg control of local cytokines and myeloid populations. Specifically, Il33–/– mice are more susceptible to lung damage-associated morbidity and mortality that is typified by augmented levels of the proinflammatory cytokines and Ly6Chi monocytes in the bronchoalveolar lavage fluid. Local delivery of IL-33 at the time of injury is protective, but requires the presence of Treg cells. IL-33 stimulates both mouse and human Treg to secrete IL-13. Using Foxp3Cre x Il4/Il13fl/fl mice, we show that Treg expression of IL-13 is required to prevent mortality after acute lung injury by controlling local levels of G-CSF, IL-6, and MCP-1 and inhibiting accumulation of Ly6Chi monocytes. Our study identifies a new regulatory mechanism involving IL-33 and Treg secretion of IL-13 in response to tissue damage that is instrumental in limiting local inflammatory responses and may shape the myeloid compartment after lung injury.
Authors
Quan Liu, Gaelen K. Dwyer, Yifei Zhao, Huihua Li, Lisa R. Mathews, Anish Bhaswanth Chakka, Uma R. Chandran, Jake A. Demetris, John F. Alcorn, Keven M. Robinson, Luis A. Ortiz, Bruce Pitt, Angus W. Thomson, Ming-Hui Fan, Timothy R. Billiar, Heth R. Turnquist
Abstract
Heart failure (HF) is associated in humans and mice with increased circulating levels of CXCL9 and CXCL10, chemokine ligands of the CXCR3 receptor, predominantly expressed on CD4+ T helper type 1 (Th1) cells. Chemokine engagement of receptors is required for T cell integrin activation and recruitment to sites of inflammation. Th1 cells drive adverse cardiac remodeling in pressure overload induced cardiac dysfunction, and mice lacking the integrin ligand ICAM-1 show defective T cell recruitment to the heart. Here, we show that CXCR3+ T cells infiltrate the heart in humans and mice with pressure overload induced cardiac dysfunction. Genetic deletion of CXCR3 disrupts CD4+ T cell heart infiltration and prevents adverse cardiac remodeling. We demonstrate that cardiac myeloid cells that include resident and infiltrated macrophages, and cardiac fibroblasts are the source of CXCL9 and CXCL10; which, mechanistically promote Th1 cell adhesion to ICAM-1 under shear conditions in a CXCR3-dependent manner. Our findings identify a previously unrecognized role for CXCR3 in Th1 cell recruitment into the heart in pressure overload induced cardiac dysfunction.
Authors
Njabulo Ngwenyama, Ane M. Salvador, Francisco Velázquez, Tania Nevers, Alexander Levy, Mark J. Aronovitz, Andrew D. Luster, Gordon S. Huggins, Pilar Alcaide
Abstract
About one-third of dilated cardiomyopathy (DCM) cases are caused by mutations in sarcomere or cytoskeletal proteins. Yet treating the cytoskeleton directly is not possible because drugs that bind to actin are not well tolerated. Mutations in the actin binding protein CAP2 can cause DCM and knockout mice, either whole body (CAP2 KO) or cardiomyocyte-specific knockouts (CAP2 CKO), develop DCM with cardiac conduction disease. RNA-seq analysis of CAP2 KO hearts and isolated cardiomyocytes revealed over-activation of fetal genes including serum response factor (SRF) regulated genes such as Myl9 and Acta2 prior to the emergence of cardiac disease. To test if we could treat CAP2 KO mice, we synthesized and tested the SRF inhibitor CCG-1423-8u. CCG-1423-8u reduced expression of the SRF targets Myl9 and Acta2, as well as the biomarker of heart failure, Nppa. The median survival of CAP2 CKO mice was 98 days, while CCG-1423-8u treated CKO mice survived for 116 days and also maintain normal cardiac function longer. These results suggest that some forms of sudden cardiac death and cardiac conduction disease are under cytoskeletal stress and that inhibiting signaling through SRF may benefit DCM by reducing cytoskeletal stress.
Authors
Yao Xiong, Kenneth C. Bedi, Simon Berritt, Thomas G. Brooks, Bennette K. Attipoe, Kevin Wang, Kenneth B. Margulies, Jeffrey Field
Abstract
Idiopathic pulmonary fibrosis (IPF) is a progressive disease with unremitting extracellular matrix deposition, leading to a distortion of pulmonary architecture and impaired gas exchange. Fibroblasts from IPF patients acquire an invasive phenotype that is essential for progressive fibrosis. Here, we performed RNA-seq analysis on invasive and non-invasive fibroblasts and found that the immune checkpoint ligand CD274 (PD-L1) was up-regulated on invasive lung fibroblasts and was required for the invasive phenotype of lung fibroblasts, is regulated by P53 and FAK, and drives lung fibrosis in a humanized IPF model in mice. Activating CD274 in IPF fibroblasts promoted invasion in vitro and pulmonary fibrosis in vivo. CD274 knockout in IPF fibroblasts and targeting CD274 by FAK inhibition or CD274 neutralizing antibodies blunted invasion and attenuated fibrosis, suggesting that CD274 may be a novel therapeutic target in IPF.
Authors
Yan Geng, Xue Liu, Jiurong Liang, David M. Habiel, Kulur Vrishika, Ana Lucia Coelho, Nan Deng, Ting Xie, Yizhou Wang, Ningshan Liu, Guanling Huang, Adrianne Kurkciyan, Zhenqiu Liu, Jie Tang, Cory M. Hogaboam, Dianhua Jiang, Paul W. Noble
Abstract
B-cells are key contributors to chronic autoimmune pathology in multiple sclerosis (MS). Clonally related B-cells exist in the cerebrospinal fluid (CSF), meninges, and central nervous system (CNS) parenchyma of MS patients. We sought to investigate the presence of clonally related B-cells over time by performing immunoglobulin heavy chain variable region repertoire sequencing on B-cells from longitudinally collected blood and CSF samples of MS patients (n=10). All patients were untreated at the time of the initial sampling; the majority (n=7) were treated with immune modulating therapies 1.2 (+/-0.3 SD) years later during the second sampling. We found clonal persistence of B-cells in the CSF of five patients; these B-cells were frequently immunoglobulin (Ig) class-switched and CD27+. We identified specific blood B-cell subsets that appear to provide input into CNS repertoires over time. We demonstrate complex patterns of clonal B-cell persistence in CSF and blood, even in patients on immune modulating therapy. Our findings support the concept that peripheral B-cell activation and CNS-compartmentalized immune mechanisms can in part therapy-resistant.
Authors
Ariele L. Greenfield, Ravi Dandekar, Akshaya Ramesh, Erica L. Eggers, Hao Wu, Sarah Laurent, William Harkin, Natalie S. Pierson, Martin S. Weber, Roland G. Henry, Antje Bischof, Bruce A.C. Cree, Stephen L. Hauser, Michael R. Wilson, H.-Christian von Büdingen
Abstract
Psoriasis (PS) is a systemic, immune-mediated inflammatory disorder. However, the whole lymphocyte compartment and the potential pathologies of PS have not been fully characterized. In the present study, we examined whole lymphocyte subsets and signal transduction proteins using high-dimensional single-cell mass cytometry and a bioinformatics pipeline for an in-depth characterization of the immune cell subsets and protein profiles involved in pathways in the peripheral blood of patients with PS. We identified 15 major immune cell populations in T cell lineages, and characterized various CD3+CD4+T helper and CD3+CD8+T cytotoxic cell populations simultaneously across 24 leukocyte markers and 7 proteins related to the signal transduction pathways. High-dimensional analysis identified three new subsets that are abundant in PS peripheral blood, resembling CD3-CD4+ lymphoid tissue inducer cells, Tc17, and CD8+CXCR3+ Tregs. We confirmed the CD3-CD4+ cells, and their features and functions, in an independent PS cohort. The use of single-cell mass cytometry allows systemic-level characterization of lymphocyte subpopulations and dysregulated signaling pathways in the blood of patients with PS, identifying abnormalities of different immune cell subsets. We validated that the CD3-CD4+ cells had elevated OX40 and decreased FRA2 expression, which were positively associated with the psoriasis area and severity index.
Authors
Ruru Guo, Ting Zhang, Xinyu Meng, Zhen Lin, Jinran Lin, Yu Gong, Xuesong Liu, Yuetian Yu, Guilin Zhao, Xianting Ding, Xiaoxiang Chen, Liangjing Lu
Abstract
Idiopathic intracranial hypertension (IIH) is a condition of unknown etiology, characterized by elevated intracranial pressure frequently manifesting with chronic headaches and visual loss. Similar to polycystic ovary syndrome (PCOS), IIH predominantly affects obese women of reproductive age. In this study, we comprehensively examined the systemic and cerebrospinal fluid (CSF) androgen metabolome in women with IIH in comparison to sex-, body mass index- and age-matched control groups with either simple obesity and PCOS, i.e. obesity and androgen excess. IIH women showed a pattern of androgen excess distinct to that observed in PCOS and simple obesity, with increased serum testosterone, and increased CSF testosterone and androstenedione. Human choroid plexus expressed the androgen receptor, alongside the androgen-activating enzyme aldoketoreductase type 1C3. We show that in a rat choroid plexus cell line testosterone significantly enhanced the activity of Na+/K+ ATPase, a surrogate of CSF secretion. We demonstrate that IIH patients have a unique signature of androgen excess and provide evidence that androgens can modulate CSF secretion via the choroid plexus. These findings implicate androgen excess as a potential causal driver and therapeutic target in IIH.
Authors
Michael W. O'Reilly, Connar S.J. Westgate, Catherine Hornby, Hannah Botfield, Angela E. Taylor, Keira Markey, James L. Mitchell, William J. Scotton, Susan P. Mollan, Andreas Yiangou, Carl Jenkinson, Lorna C. Gilligan, Mark Sherlock, James Gibney, Jeremy W. Tomlinson, Gareth G. Lavery, David J. Hodson, Wiebke Arlt, Alexandra J. Sinclair
Abstract
Chimeric antigen receptor (CAR) technology can be used to engineer the antigen-specificity of regulatory T cells (Tregs) and improve their potency as an adoptive cell therapy in multiple disease models. As synthetic receptors, CARs carry the risk of immunogenicity, particularly when derived from non-human antibodies. Using an HLA-A*02:01-specific CAR (A2-CAR) encoding a single-chain Fv derived from a mouse antibody, we developed a panel of 20 humanized (h)A2-CARs. Systematic testing demonstrated variations in expression, ability to bind HLA-A*02:01, and stimulate human Treg suppression in vitro. In addition, we developed a new method to comprehensively map the alloantigen-specificity of CARs, revealing that humanization reduced HLA-A cross reactivity. In vivo bioluminescence imaging showed rapid trafficking and persistence of hA2-CAR Tregs in A2-expressing allografts, with eventual migration to draining lymph nodes. Adoptive transfer of hA2-CAR Tregs suppressed HLA-A2+ cell mediated xenogeneic graft-versus-host disease and diminished rejection of human HLA-A2+ skin allografts. These data provide a platform for systematic development and specificity testing of humanized alloantigen-specific CARs which can be used to engineer specificity and homing of therapeutic Tregs.
Authors
Nicholas A.J. Dawson, Caroline Lamarche, Romy E. Hoeppli, Peter Bergqvist, Vivian Fung, Emma McIver, Qing Huang, Jana Gillies, Madeleine Speck, Paul C. Orban, Jonathan W. Bush, Majid Mojibian, Megan K. Levings
Abstract
Recovery from acute lung injury (ALI) is an active process. Foxp3+ regulatory T cells (Tregs) contribute to recovery from ALI through modulating immune responses and enhancing alveolar epithelial proliferation and tissue repair. The current study investigates Treg transcriptional profiles during resolution of ALI in mice. Tregs from either lung or splenic tissue were isolated from uninjured mice or mice recovering from ALI and then examined for differential gene expression between these conditions. In mice with ALI, Tregs isolated from the lungs had hundreds of differentially expressed transcripts compared to those from the spleen, indicating that organ-specificity and microenvironment are critical in Treg function. These regulated transcripts suggest which intracellular signaling pathways modulate Treg behavior. Interestingly, several transcripts having no prior recognized function in Tregs were differentially expressed by lung Tregs during resolution. Further investigation into two identified transcripts, Mmp12 and Sik1, revealed that Treg-specific expression of each play a role in Treg-promoted ALI resolution. This study provides novel information describing the signals that may expand resident Tregs, recruit or retain them to the lung during ALI, and modulate their function. The results provide insight into both tissue- and immune microenvironment-specific transcriptional differences through which Tregs direct their effects.
Authors
Jason R. Mock, Catherine F. Dial, Miriya K. Tune, Dustin L. Norton, Jessica R. Martin, John C. Gomez, Robert S. Hagan, Hong Dang, Claire M. Doerschuk
Abstract
Myotonic dystrophy (DM) is the most common autosomal dominant muscular dystrophy and encompasses both skeletal muscle and cardiac complications. Myotonic dystrophy is nucleotide repeat expansion disorder in which type 1 (DM1) is due to a trinucleotide repeat expansion on chromosome 19 and type 2 (DM2) arises from a tetranucleotide repeat expansion on chromosome 3. Developing representative models of myotonic dystrophy in animals has been challenging due to instability of nucleotide repeat expansions, especially for DM2 which is characterized by nucleotide repeat expansions often greater than 5000 copies. To investigate mechanisms of human DM, we generated cellular models of DM1 and DM2. We used regulated MyoD expression to reprogram urine-derived cells into myotubes. In this myogenic cell model, we found impaired dystrophin expression, MBNL foci, and aberrant splicing in DM1 but not in DM2 cells. We generated induced pluripotent stem cells (iPSC) from healthy controls, DM1 and DM2 subjects and differentiated these into cardiomyocytes. DM1 and DM2 cells displayed an increase in RNA foci concomitant with cellular differentiation. IPSC-derived cardiomyocytes from DM1 but not DM2 had aberrant splicing of known target genes and MBNL sequestration. High resolution imaging revealed tight association between MBNL clusters and RNA FISH foci in DM1. Ca2+ transients differed between DM1 and DM2 IPSC-derived cardiomyocytes and each differed from healthy control cells. RNA-sequencing from DM1 and DM2 iPSC-derived cardiomyocytes revealed distinct misregulation of gene expression as well as differential aberrant splicing patterns. Together these data support that DM1 and DM2, despite some shared clinical and molecular features, have distinct pathological signatures.
Authors
Ellis Y. Kim, David Y. Barefield, Andy H. Vo, Anthony M. Gacita, Emma J. Schuster, Eugene J. Wyatt, Janel L. Davis, Biqin Dong, Cheng Sun, Patrick Page, Lisa Dellefave-Castillo, Alexis Demonbreun, Hao F. Zhang, Elizabeth M. McNally
Abstract
Although Type-2 (T2) induced epithelial dysfunction is likely to profoundly alter epithelial differentiation and repair in asthma, the mechanisms for these effects are poorly understood. A role for specific mucins, heavily N-glycosylated epithelial glycoproteins, in orchestrating epithelial cell fate in response to T2 stimuli has not previously been investigated. Levels of a sialylated MUC4β isoform were found to be increased in airway specimens from asthmatic patients, in association with T2 inflammation. We hypothesized that IL-13 would increase sialylation of MUC4β, thereby altering its function and that the β-galactoside α-2,6-sialyltranferase 1 (ST6GAL1) would regulate the sialylation. Using human biologic specimens and cultured primary human airway epithelial cells (HAECs), we demonstrated that IL-13 increased sialylation of MUC4β under control of ST6GAL1, and that both were increased in asthma, particularly in those with elevated T2 biomarkers. ST6GAL1 induced sialylation of MUC4β altered its lectin binding and secretion. Both ST6GAL1 and MUC4β inhibited epithelial cell proliferation while promoting goblet cell differentiation. These in vivo and in vitro data provide strong evidence for a critical role for ST6GAL1 induced sialylation of MUC4β in epithelial dysfunction associated with T2-High asthma, thereby identifying specific sialylation pathways as potential targets in asthma.
Authors
Xiuxia Zhou, Carol L. Kinlough, Rebecca P. Hughey, Mingzhu Jin, Hideki Inoue, Emily Etling, Brian D. Modena, Naftali Kaminski, Eugene R. Bleecker, Deborah A. Meyers, Nizar N. Jarjour, John B. Trudeau, Fernando Holguin, Anuradha Ray, Sally E. Wenzel
Abstract
The circadian clock network is an evolutionally conserved system involved in the regulation of metabolic homeostasis; however, its impacts on skeletal metabolism remain largely unknown. We herein demonstrated that circadian clock network in the intestines plays pivotal roles in skeletal metabolism such that the lack of Bmal1 gene in the intestines (Bmal1Int-/- mice) caused bone loss with bone resorption being activated and bone formation suppressed. Mechanistically, Clock interaction with Vitamin D receptor (Vdr) accelerated its binding to VDR response element by enhancing histone acetylation in a circadian-dependent manner, and this was lost in Bmal1Int-/- mice because nuclear translocation of Clock required the presence of Bmal1. Accordingly, the rhythmic expression of Vdr-target genes involved in transcellular calcium (Ca) absorption was created, and this was not observed in Bmal1Int-/- mice. As a result, transcellular Ca absorption was impaired and bone resorption was activated in Bmal1Int-/- mice. Additionally, sympathetic tone, the activation of which suppresses bone formation, was elevated through afferent vagal nerves in Bmal1Int-/- mice, the blockade of which partially recovered bone loss by increasing bone formation and suppressing bone resorption in Bmal1Int-/- mice. These results demonstrate that the intestinal circadian system regulates skeletal bone homeostasis.
Authors
Masanobu Kawai, Saori Kinoshita, Miwa Yamazaki, Keiko Yamamoto, Clifford J. Rosen, Shigeki Shimba, Keiichi Ozono, Toshimi Michigami
Abstract
Epithelial ovarian cancer (EOC) often presents with metastases and ascites. Granulocytic myeloid-derived suppressor cells are an immature population that impairs anti-tumor immunity. Since suppressive granulocytes in the ascites of patients with newly diagnosed EOC were morphologically mature, we hypothesized that PMN were rendered suppressive in the tumor microenvironment. Circulating PMN from patients were not suppressive, but acquired a suppressor phenotype (defined as ≥ 1 log10 reduction of anti-CD3/CD28-stimulated T cell proliferation) after ascites supernatant exposure. Ascites supernatants (20/31) recapitulated the suppressor phenotype in PMN from healthy donors. T cell proliferation was restored with ascites supernatant removal and re-stimulation. PMN suppressors also inhibited T cell activation and cytokine production. PMN suppressors completely suppressed proliferation in naïve, central memory, and effector memory T cells, and in engineered tumor antigen-specific cytotoxic T lymphocytes, while antigen-specific cell lysis was unaffected. Inhibition of complement C3 activation and PMN effector functions, including CR3 signaling, protein synthesis, and vesicular trafficking, abrogated the PMN suppressor phenotype. Moreover, malignant effusions from patients with various metastatic cancers also induced the C3-dependent PMN suppressor phenotype. These results point to PMN impairing T cell expansion and activation in the tumor microenvironment and the potential for complement inhibition to abrogate this barrier to anti-tumor immunity.
Authors
Kelly L. Singel, Tiffany R. Emmons, ANM Nazmul H. Khan, Paul C. Mayor, Shichen Shen, Jerry T. Wong, Kayla Morrell, Kevin H. Eng, Jaron Mark, Richard B. Bankert, Junko Matsuzaki, Richard C. Koya, Anna M. Blom, Kenneth R. McLeish, Jun Qu, Sanjay Ram, Kirsten B. Moysich, Scott I. Abrams, Kunle Odunsi, Emese Zsiros, Brahm H. Segal
