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Abstract
Vascular injury has emerged as a complication contributing to morbidity in coronavirus disease 2019 (COVID-19). The glycosaminoglycan hyaluronan (HA) is a major component of the glycocalyx, a protective layer of glycoconjugates that lines the vascular lumen and regulates key endothelial cell functions. During critical illness as in the case of sepsis, enzymes degrade the glycocalyx, releasing fragments with pathologic activities into circulation and thereby exacerbate disease. Here, we analyzed levels of circulating glycosaminoglycans in 46 patients with COVID-19 ranging from moderate to severe clinical severity and measured activities of corresponding degradative enzymes. This report provides evidence that the glycocalyx becomes significantly damaged in COVID-19 patients and corresponds with severity of disease. Circulating HA fragments and hyaluronidase, two signatures of glycocalyx injury, strongly associate with sequential organ failure assessment scores and with increased inflammatory cytokine levels in COVID-19 patients. Pulmonary microvascular endothelial cells exposed to COVID-19 milieu show dysregulated HA biosynthesis and degradation leading to production of pathological HA fragments which are released into circulation. Finally, we show that HA fragments present at high levels in COVID-19 patient plasma can directly induce endothelial barrier dysfunction in ROCK- and CD44-dependent manner, indicating a role for HA in the vascular pathology of COVID-19.
Authors
Kimberly A. Queisser, Rebecca A. Mellema, Elizabeth A. Middleton, Irina Portier, Bhanu Kanth Manne, Frederik Denorme, Ellen J. Beswick, Matthew T. Rondina, Robert A. Campbell, Aaron C. Petrey
Abstract
Macrophage activation syndrome (MAS) is a life-threatening cytokine storm complicating systemic juvenile idiopathic arthritis (SJIA) driven by IFNγ. SJIA and MAS are associated with an unexplained emerging lung disease (SJIA-LD), with our recent work supporting pulmonary activation of IFNγ pathways pathologically linking SJIA-LD and MAS. Our objective was to mechanistically define the novel observation of pulmonary inflammation in the TLR9 mouse model of MAS. In acute MAS, lungs exhibit mild but diffuse CD4-predominant, perivascular interstitial inflammation with elevated IFNγ, IFN-induced chemokines, and AMΦ expression of IFNγ-induced genes. Single-cell RNA-sequencing confirmed IFN-driven transcriptional changes across lung cell types with myeloid expansion and detection of MAS-specific macrophage populations. Systemic MAS resolution was associated with increased AMΦ and interstitial lymphocytic infiltration. AMΦ transcriptomic analysis confirmed IFNγ-induced proinflammatory polarization during acute MAS, which switches towards an anti-inflammatory phenotype after systemic MAS resolution. Interestingly, recurrent MAS led to increased alveolar inflammation and lung injury, and reset AMΦ polarization towards a proinflammatory state. Furthermore, in mice bearing macrophages insensitive to IFNγ, both systemic feature of MAS and pulmonary inflammation were attenuated. These findings demonstrate that experimental MAS induces IFNγ-driven pulmonary inflammation replicating key features of SJIA-LD, and provides a model system for testing novel treatments directed towards SJIA-LD.
Authors
Denny K. Gao, Nathan Salomonis, Maggie Henderlight, Christopher Woods, Kairavee Thakkar, Alexei A. Grom, Sherry Thornton, Michael B. Jordan, Kathryn A. Wikenheiser-Brokamp, Grant S. Schulert
Abstract
The mechanism controlling long-chain fatty acid (LCFA) mobilization from adipose tissue (AT) is not well understood. Here, we investigated how the LCFA transporter CD36 regulates this process. By using tissue-specific knockout mouse models, we show that CD36 in both adipocytes and endothelial cells mediates both LCFA deposition into and release from AT. We demonstrate the role of adipocytic and endothelial CD36 in promoting tumor growth and chemoresistance conferred by AT-derived LCFA. We show that dynamic cysteine S-acylation of CD36 in adipocytes, endothelial cells, and cancer cells mediates intercellular LCFA transport. We demonstrate that lipolysis induction in adipocytes triggers CD36 de-acylation and deglycosylation, as well as its dissociation from interacting proteins, prohibitin-1 (PHB), and annexin 2 (ANX2). Our data indicate that lipolysis triggers caveolar endocytosis and translocation of CD36 from the cell membrane to lipid droplets. This study suggests a mechanism for both outside-in and inside-out cellular LCFA transport regulated by CD36 S- acylation and its interactions with PHB and ANX2.
Authors
Alexes C. Daquinag, Zhanguo Gao, Cale Fussell, Linnet Immaraj, Renata Pasqualini, Wadih Arap, Askar M. Akimzhanov, Maria Febbraio, Mikhail G. Kolonin
Abstract
Immunotherapies are needed in the clinic that effectively suppress beta cell autoimmunity and reestablish long-term self-tolerance in type 1 diabetes. We previously demonstrated that nondepleting αCD4 and αCD8α antibodies establish rapid and indefinite remission in recent-onset diabetic NOD mice. Diabetes reversal by coreceptor therapy (CoRT) is induced by suppression of pathogenic effector T cells (Teff) and the selective egress of T cells from the pancreatic lymph nodes and islets that remain free of infiltration long-term. Here, we defined CoRT-induced events regulating early Teff function and pancreatic residency, and long-term tolerance. TCR-driven gene expression controlling autoreactive Teff expansion and proinflammatory activity was suppressed by CoRT, and islet T cell egress was sphingosine-1 phosphate-dependent. In both murine and human T cells, CoRT upregulated the Foxo1 transcriptional axis, which in turn was required for suppression and efficient pancreatic egress of Teff. Interestingly, long-term tolerance induced in late-preclinical NOD mice was marked by reseeding of the pancreas by a reduced CD8+ Teff pool exhibiting an exhausted phenotype. Notably, PD-1 blockade, which rescues exhausted Teff, resulted in diabetes onset in protected animals. These findings demonstrate that CoRT has distinct intrinsic effects on Teff that impact events early in induction and later in maintenance of self-tolerance.
Authors
Matthew Clark, Charles J. Kroger, Qi Ke, Rui Zhang, Karen Statum, J. Justin Milner, Aaron J. Martin, Bo Wang, Roland Tisch
Abstract
Hyperstimulation of the cholecystokinin receptor (CCK1R), a Gq-protein coupled receptor (GPCR), in pancreatic acinar cells is commonly used to induce pancreatitis in rodents. Human pancreatic acinar cells lack CCK1R but express cholinergic receptor muscarinic 3 (M3R), another GPCR. To test whether M3R activation is involved in pancreatitis, a mutant M3R was conditionally expressed in pancreatic acinar cells in mice. This mutant receptor loses responsiveness to its native ligand acetylcholine but can be activated by an inert small molecule, clozapine-N-oxide (CNO). Intracellular calcium and amylase were elicited by CNO in pancreatic acinar cells isolated from mutant M3R mice but not WT mice. Similarly, acute pancreatitis (AP) could be induced by a single injection of CNO in the transgenic mice but not WT mice. Compared with the cerulein-induced AP, CNO caused more widespread acinar cell death and inflammation. Furthermore, chronic pancreatitis developed at 4 weeks after 3 episodes of CNO-induced AP. In contrast, in mice with three recurrent episodes of cerulein-included AP, pancreas histology was restored in 4 weeks. Furthermore, the M3R antagonist ameliorated the severity of cerulein-induced AP in WT mice. We conclude that M3R activation can cause the pathogenesis of pancreatitis. This model may provide an alternative approach for pancreatitis research.
Authors
Jianhua Wan, Jiale Wang, Larry E. Wagner II, Oliver H. Wang, Fu Gui, Jiaxiang Chen, Xiaohui Zhu, Ashley N. Haddock, Brandy H. Edenfield, Brian Haight, Debabrata Mukhopadhyay, Ying Wang, David I. Yule, Yan Bi, Baoan Ji
Abstract
Lack of sustained response to therapeutic agents in patients with KRAS mutant lung cancer poses a major challenge and arises partly due to intratumor heterogeneity that defines phenotypically distinct tumor subpopulations. To attain better therapeutic outcomes it is important to understand the differential therapeutic sensitivities of tumor cell subsets. Epithelial-to-mesenchymal transition (EMT) is a biologic phenomenon that can alter the state of cells along a phenotypic spectrum and cause transcriptional rewiring to produce distinct tumor cell subpopulations. We utilized functional shRNA screens, in vitro and in vivo models to identify and confirm an increased dependence of mesenchymal tumor cells on CDK4 for survival, as well as a mechanism of resistance to MEK inhibitors. High ZEB1 levels in mesenchymal tumor cells repressed p21, leading to perturbed CDK4 pathway activity. Increased dependence on CDK4 rendered mesenchymal cancer cells particularly vulnerable to selective CDK4 inhibitors. Co-administration of CDK4 and MEK inhibitors in heterogeneous tumors effectively targeted different tumor subpopulations, subverting the resistance to either single agent treatment.
Authors
Aparna Padhye, Jessica M. Konen, B. Leticia Rodriguez, Jared J. Fradette, Joshua K. Ochieng, Lixia Diao, Jing Wang, Wei Lu, Luisa S. Solis, Harsh Batra, Maria G. Raso, Michael D. Peoples, Rosalba Minelli, Alessandro Carugo, Christopher A. Bristow, Don L. Gibbons
Abstract
The metabolic environment is important for neuronal cells, such as photoreceptors. When photoreceptors undergo degeneration, as occurs during retinitis pigmentosa (RP), patients have progressive loss of vision that proceeds to full blindness. Currently, there are no available treatments for the majority of RP diseases. We performed metabolic profiling of the neural retina in a preclinical model of RP and found that tricarboxylic acid (TCA) cycle intermediates were reduced during disease. We then determined that, 1) promoting citrate production within the TCA cycle in retinal neurons during disease progression protects the photoreceptors from cell death and prolongs visual function, 2) that supplementation with single metabolites within the TCA cycle can provide this therapeutic effect in vivo over time, and, 3) that this therapeutic effect is not specific to a particular genetic mutation but has broad applicability for patients with RP and other retinal degenerative diseases. Overall, targeting TCA cycle activity in the neural retina promotes photoreceptor survival and visual function during neurodegenerative disease.
Authors
Ashley A. Rowe, Pinkal D. Patel, Ruth Gordillo, Katherine J. Wert
Abstract
Aging is associated with chronic oxidative stress and inflammation that impact the tissue repair and regeneration capacity. MG53 is a TRIM family protein that facilitates repair of cell membrane injury in a redox-dependent manner. Here we demonstrate that the expression of MG53 is reduced in failing human heart and aging mouse heart, concomitant with elevated NFκB activation. We evaluate the safety and efficacy of longitudinal, systemic administration of recombinant human MG53 (rhMG53) protein in aged mice. Echocardiography and pressure-volume loop measurements reveal beneficial effects of rhMG53 treatment in improving heart function of aging mice. Biochemical and histological studies demonstrate the cardioprotective effects of rhMG53 are linked to suppression of NFκB-mediated inflammation, reducing apoptotic cell death and oxidative stress in the aged heart. Repetitive administrations of rhMG53 in aged mice do not have adverse effects on major vital organ functions. These findings support the therapeutic value of rhMG53 in treating age-related decline in cardiac function.
Authors
Xiaoliang Wang, Xiuchun Li, Hannah Ong, Tao Tan, Ki Ho Park, Zehua Bian, Xunchang Zou, Erin Haggard, Paul M. Janssen, Robert E. Merritt, Timothy M. Pawlik, Bryan A. Whitson, Nahush A. Mokadam, Lei Cao, Hua Zhu, Chuanxi Cai, Jianjie Ma
Abstract
Retinoic Acid (RA) signaling has long been speculated to regulate embryo implantation, because many enzymes and proteins responsible for maintaining RA homeostasis and transducing RA signals are tightly regulated in the endometrium during this critical period. However, due to lack of genetic data, it was unclear whether RA signaling is truly required for implantation, and which specific RA signaling cascades are at play. Herein we utilize a genetic murine model that expresses a dominant negative form of RA receptor specifically in female reproductive organs to show that functional RA signaling is fundamental to female fertility, particularly implantation and decidualization. Reduction in RA signaling activity severely affects the ability of the uterus to achieve receptive status and decidualize, partially through dampening follistatin expression and downstream activin B/BMP2 signaling. To confirm translational relevance of these findings to humans, human endometrial stromal cells (hESCs) were treated with pan-RAR antagonist to show that in vitro decidualization is impaired. RNAi perturbation of individual RAR transcripts in hESCs revealed that RARα in particular is essential for proper decidualization. These data provide direct functional evidence that uterine RAR-mediated RA signaling is crucial for mammalian embryo implantation, and its disruption leads to failure of uterine receptivity and decidualization resulting in severely compromised fertility.
Authors
Yan Yin, Meade E. Haller, Sangappa B. Chadchan, Ramakrishna Kommagani, Liang Ma
Abstract
BACKGROUND. Epicardial adipose tissue (EAT) directly overlies the myocardium with changes in its morphology and volume associated with myriad cardiovascular and metabolic diseases. However, EAT’s immune structure and cellular characterization remain incompletely described. This study aimed to define the immune phenotype of EAT in humans, and compare such profiles across lean, obese and diabetic patients. METHODS. A total of 152 adult patients undergoing open chest coronary artery bypass grafting (CABG), valve repair/replacement (VR) surgery or combined CABG/valve surgery were recruited to the study. Patients’ clinical and biochemical data alongside epicardial adipose tissue (EAT), subcutaneous adipose tissue (SAT) and pre-operative blood samples were collected. Immune cell profiling was evaluated by flow cytometry and complemented by gene expression studies of immune mediators. Bulk RNA-seq was performed in EAT across different metabolic profiles to assess whole transcriptome changes observed in these groups. RESULTS. Flow cytometry analysis demonstrated that EAT is highly enriched in adaptive immune (T and B) cells. Whilst overweight/obese and diabetic patients had similar EAT cellular profiles to lean control patients, the EAT exhibited significantly (P≤.01) raised expression of immune mediators including: interleukin1 (IL1), IL6, tumour necrosis factorα (TNFα) and interferonγ (IFNγ). These changes were not observed in either SAT or blood. Neither underlying coronary artery disease nor the presence of hypertension significantly altered the immune profiles observed. Bulk RNA-seq demonstrated significant alterations in metabolic and inflammatory pathways in the EAT of overweight/obese patients compared with lean controls. CONCLUSIONS. Adaptive immune cells are the predominant immune cell constituent in human EAT and SAT. The presence of underlying cardiometabolic conditions, specifically obesity and diabetes, rather than cardiac disease phenotype appears to alter the inflammatory profile of EAT. Obese states markedly alter EAT metabolic and inflammatory signalling genes, underlining the impact of obesity on the EAT transcriptome profile.
Authors
Vishal Vyas, Hazel Blythe, Elizabeth G. Wood, Balraj Sandhar, Shah-Jalal Sarker, Damian Balmforth, Shirish G. Ambekar, John Yap, Stephen J. Edmondson, Carmelo Di Salvo, Kit Wong, Neil Roberts, Rakesh Uppal, Ben Adams, Alex Shipolini, Aung Y. Oo, David Lawrence, Shyam Kolvekar, Kulvinder S. Lall, Malcolm C. Finlay, M. Paula Longhi
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