Vascular biology
Abstract
Glucagon-like peptide-1 (GLP-1) and glucose-induced insulinotropic polypeptide (GIP) receptor agonists have revolutionized obesity therapy but causes for obesity-associated dysregulation of endogenous incretin production remain incompletely understood. Here we show that intestinal transmembrane serine protease 2 (TMPRSS2) plays a pivotal role in deregulating anti-diabetic GLP-1 production in obesity. TMPRSS2 is widely co-expressed in intestinal epithelial cells (IEC) along with its signaling target protease activated receptor 2 (PAR2). In addition to its role in regulating coagulation protease-mediated adipose tissue inflammation, PAR2 signaling in the gut controls postprandial GIP secretion. TMPRSS2, but not the epithelial-expressed proteases FXa or matriptase, activates PAR2 and thereby promotes postprandial GIP release. Accordingly, a PAR2 mutant mouse resistant to TMPRSS2 cleavage is protected from GIP upregulation and diet induced obesity. In the context of obesity, TMPRSS2 also attenuates bioavailability of ghrelin pathway and thereby suppresses GLP-1-mediated control of glucose homeostasis. Pharmacological inhibition or genetic deletion of TMPRSS2 restores ghrelin signaling dependent GLP-1 secretion and GLP-1’s anti-diabetic effects on nutritional glucose homeostasis. Thus, epithelial cell-expressed TMPRSS2, which critically contributes to the lung pathology in SARS-CoV-2 infection, emerges as an intestinal incretin regulator and a potential link between infection and chronic cardiometabolic diseases.
Authors
Dilraj Kaur, Sagarika Chakrabarty, Claudius Witzler, Hongjie Wang, Mengwen Wang, Romina Wolz, Petra Wilgenbus, Jens J.N. Posma, P. Sivaramakrishna Rachakonda, Federico Marini, Valeriya V. Zinina, Sabine Reyda, Rajinikanth Gogiraju, Claudine Graf, Fahumiya Samad, Katrin Schäfer, Christoph Reinhardt, Natalia Soshnikova, Wolfram Ruf, Thati Madhusudhan
Abstract
Aberrant neutrophil (PMN) accumulation in the tissue induces chronic vascular diseases. Endothelial cells (ECs) regulate the access of PMNs into the tissue from the blood. However, the mechanisms that prevent PMNs from being activated and accumulating in the tissue, a hallmark of acute lung injury (ALI), remain elusive. We demonstrate that conditional deletion of Erg in ECs spontaneously alters the PMN transcriptome, which is enriched with genes that induce PMN recruitment, adhesion, activation, and 'do not eat me' signals due to impaired synthesis of the deubiquitinase, A20. Decreased A20 levels, in turn, activated the transcription factor NFκB and the secretion of MIP2α (human homolog of IL8) in ECs. EC-secreted MIP2α/IL8 engaged the CXCR2 cascade on PMNs, leading to their activation and inflammatory injury. These findings were recapitulated in the lungs and blood of PMNs from patients dying of ALI. Overexpression of the A20 gene in EC or pharmacological inhibition of CXCR2 on PMNs in iEC-Erg–/– mice rescued EC control of PMNs and tissue homeostasis, and enhanced mouse survival after pneumonia. Thus, the EC-Erg-A20 axis regulates PMN accumulation and hyperactivation in the lungs by inhibiting EC-mediated IL-8 activation of PMN-CXCR2, thereby providing a potential target for neutrophilic inflammatory vascular diseases.
Authors
Vigneshwaran Vellingiri, Vijay Avin Balaji Ragunathrao, Jagdish Chandra Joshi, Md Zahid Akhter, Mumtaz Anwar, Somenath Banerjee, Sayanti Datta, Viktor Pinneker, Steven M. Dudek, Yoshikazu Tsukasaki, Sandra Pinho, Dolly Mehta
Abstract
Patients with COVID-19 who develop platelet-activating antibodies represent a subset at heightened thrombotic risk, yet the immune features associated with this response remains to be defined. We applied single-cell RNA sequencing of B- and T-cells, single B-cell V(D)J sequencing, and plasma cytokine and chemokine analysis to define immune signatures distinguishing patients who did (PEA+) or did not (PEA–) develop these antibodies. PEA⁺ patients showed prominent transcriptional enrichment of inflammatory, antigen-presentation, and B-cell receptor signaling pathways within antigen-experienced B-cell subsets. Expanded B-cell clones in PEA+ patients were disproportionately enriched within atypical memory B-cells and exhibited upregulated IFN-γ–response signatures, increased proliferative mutational patterns, limited class switching, and a significant overrepresentation of RKH/Y5 heavy-chain motifs associated with platelet-activating antibodies, consistent with an extrafollicular-biased response. Parallel T-cell profiling revealed IL-12 pathway enrichment across most T-cell subsets, increased IFN-γ transcription, and elevated plasma levels of Th1-associated cytokines in PEA+ patients. Collectively, these data highlight a coordinated inflammatory environment marked by Th1-skewed T-cell activation and selective expansion of atypical memory B-cell clones carrying RKH/Y5 motifs, defining immunologic features associated with platelet-activating antibody development in COVID-19.
Authors
Nathan Witman, Mei Yu, Yuqi Zhang, Kexin Gai, Yuhong Chen, Lu Zhou, Christine Nguyen, Wen Zhu, Yongwei Zheng, Shawn M. Jobe, Mary Beth Graham, Weiguo Cui, Demin Wang, Renren Wen
Abstract
Angiopoietin-2 (ANGPT2) is known to destabilize vascular barriers in most peripheral organs; however, its role in the brain vasculature remains poorly understood. To investigate its physiological function within the brain vasculature, we analyzed constitutive Angpt2 knockout (KO) mice in adulthood. We showed that loss of ANGPT2 leads to region-specific vascular malformations and blood-brain barrier (BBB) dysfunction, resulting in differential permeability to 1 kDa and 70 kDa fluorescent tracers. Notably, overt vascular malformations appeared only in select brain regions that allowed leakage of both tracers. These malformations were characterized by dilated, intertwined, and sprouting endothelial cells, surrounded by reactive perivascular cells, along with high levels of astrocyte- and neuron-derived vascular endothelial growth factor A (VEGFA) and elevated expression of the vascular receptors VEGF receptor 2 (KDR) and neuropilin 1 (NRP1). Other cortical areas without obvious malformations exhibited significant leakage of the 1 kDa tracer. We also demonstrated that different cell types took up the tracers after passing the BBB. Our findings identified ANGPT2 as an important factor involved in the regulation of cerebrovascular architecture, barrier integrity, and endothelial–parenchymal interactions, and uncovered surprising differences in the leakage patterns and cellular uptake of two widely used BBB tracers.
Authors
Weihan Li, Elisa Vázquez-Liébanas, Chanaëlle Fébrissy, Florent Sauvé, Jianhao Wang, Doğan Emre Sayıner, Pia Buslaps, Amanda Norrén, Michael Vanlandewijck, Liqun He, Marie Jeansson, Lars Muhl, Maarja Andaloussi Mäe
Abstract
Oxidative signaling is a central mechanism in alcohol-induced injury and has a strong implication in blood-brain barrier (BBB) dysregulation and neuroinflammation. Here, by targeting oxidative signaling, we hypothesized an innovative approach to develop a clinically relevant therapeutic strategy for alleviating alcohol-mediated neurovascular damage. To accomplish this, we enhanced the endogenous activity of Nrf2 (nuclear factor E2-related factor 2) by treating with an Nrf2 activator III TAT peptide (Nrf2 peptide, NP) and investigated the neuroprotective role of Nrf2 in promoting antioxidant defense properties and reducing BBB damage and transmigration of leukocytes to the brain following alcohol ingestion. We administered the NP subcutaneously to alcohol-ingested mice and evaluated its therapeutic potential in alleviating alcohol-associated neurovascular impairments. We compared the results with control peptide (random sequence with TAT)-treated animals. The studies showed that the NP treatment preserved the oxidant-antioxidant balance, downregulated ICAM-1 and its receptors, and mitigated BBB damage and leukocyte infiltration into the brain. We validated the effect of the NP in Nrf2 knock-out (KO) mice (Nrf2−/−). Thus, this study demonstrates NP’s neurovascular protective effects by regulating the oxidant-antioxidant balance, reducing oxidative stress-induced BBB disruption, and limiting transmigration of immune cells to the brain in a mouse model of alcohol ingestion.
Authors
Bibhuti B. Saikia, Saleena Alikunju, Yemin A. Poovanthodi, Zayan Kassim, P. M. Abdul Muneer
Abstract
Proper development of the umbilical cord and placental vasculature is essential for embryonic development. While the allantois is known give rise to endothelial cells (ECs) within the placenta, whether the allantois gives rise to ECs in the umbilical cord is debated. Furthermore, a lack of genetic tools to study placental vascular development independent of the embryo proper has hindered robust investigation into the primary cause of vascular defects from early studies utilizing global knockouts. In this study, we delineate the contribution of the allantois to the umbilical vessels and utilize a mouse genetic tool previously developed by our lab to revisit the role of Notch signaling during placental development. We show that the allantois has mosaic contribution to the umbilical endothelium with higher contributions closer to the placenta. Allantoic deletion of Dll4 disrupts umbilical cord and placental vascular formation with secondary defects in the heart. Lastly, we identify Unc5b downstream of Notch signaling that restricts EC migration while promoting chemokine signaling for smooth muscle cell (SMC) recruitment to arteries. These findings identify a genetic tool for investigating placental vascular development and give new insights into the ontogeny and mechanisms of placental vascular and umbilical cord development.
Authors
Derek C. Sung, Hana A. Ahanger, Sweta Narayan, Jesse A. Pace, Mei Chen, Jisheng Yang, Siqi Gao, T.C.S. Keller IV, Jenna Bockman, Xiaowen Chen, Erica Nguyen, Alan T. Tang, Patricia Mericko-Ishizuka, Ivan Maillard, Mark L. Kahn
Abstract
Mutation of KRAS in endothelial cells (KRAS-EC) leads to intracerebral hemorrhage (ICH) in brain arteriovenous malformations (bAVM), resulting in severe disabilities or even death. However, it is unclear what causes this hemorrhagic conversion of bAVM. Here, using a locally established, clinically-relevant sporadic bAVM mouse model, created by overexpressing mutant KRAS (KRASG12V) in the brain EC, we demonstrate that KRAS-EC act as trigger for microglia (MG) activation and infiltration of macrophages (Mϕ). Using three-dimensional immunostaining approach with cleared human and mouse bAVM tissues, we demonstrate an abundance of MG/Mϕ around the bAVM nidus. The presence of MG/Mϕ are correlated to the blood-brain barrier leakage in bAVM area. Time-lapsed intravital imaging in Cx3cr1-gfp;Ccr2-rfp reporter mice demonstrate the dynamic activation of MG and infiltration of Mϕ toward mutant KRAS-modified dysplastic vessels. Importantly, a time course analysis showed that these activated/infiltrated MG/Mϕ are present around the bAVMs prior to hemorrhagic conversion, and controlled depletion of MG/Mϕ reduced ICH incidence in bAVM. Inhibition of MG/Mϕ with long-term minocycline treatment attenuated the incidence of ICHs around bAVMs. Our study indicates that MG/Mϕ are involved in destabilization of KRAS-induced bAVM, leading to hemorrhagic conversion/ICH. Thus, modulation of MG/Mϕ may reduce ICH risk in bAVM patients.
Authors
Hyejin Park, Jung-Eun Park, Bridger H. Freeman, Bosco Seong Kyu Yang, Shun-Ming Ting, Alexander K. Suh, Jude P.J. Savarraj, Shuning Huang, Jakob Körbelin, Huimahn Alex Choi, Sean P. Marrelli, Jaroslaw Aronowski, Peng Roc Chen, Eunhee Kim, Eun S. Park
Abstract
Although renal fibrosis is predominantly driven by the accumulated inflammatory cells that secrete pro-inflammatory factors within the kidney, the key mechanisms underlying macrophage clearance from the kidney are not well understood. The interaction of hyaluronan (HA) with lymphatic endothelial hyaluronan receptor 1 (LYVE1) constitutes a critical initial step in macrophage adhesion and removal by lymphatic vessels. This study investigates alterations in LYVE1 during kidney disease and elucidates its role in macrophage trafficking. Three renal fibrosis models demonstrated a reduction in full-length LYVE1 and an increase in the soluble LYVE1 fragment. Immunostaining of fibrotic kidneys showed significantly reduced expression of soluble LYVE1 compared with intracellular fragment (Cyto-LYVE1), demonstrating ectodomain shedding of LYVE1 in vivo and in vitro. Functionally, human lymphatic endothelial cells exposed to TGF-β1 exhibited significant decrease in macrophage adhesion and transendothelial migration compared to controls. Mechanistic analyses identified increased matrix metalloproteinase (MMP)9 in renal injury as a key upstream regulator of LYVE1 shedding. MMP9 inhibitors reduced LYVE1 shedding, enhanced macrophage adhesion and trafficking, and mitigated macrophage accumulation and disease progression. In conclusion, MMP9-induced LYVE1 shedding is linked to progressive kidney fibrosis and macrophage accumulation. LYVE1 shedding inhibitors offer potential as therapeutic agents for mitigating immune overload and kidney fibrosis.
Authors
Jing Liu, Yuqing Liu, Wenqian Zhou, Saiya Zhu, Jianyong Zhong, Haichun Yang, Annet Kirabo, Valentina Kon, Chen Yu
Abstract
BACKGROUND. Idiopathic pulmonary arterial hypertension (IPAH) alters right ventricular size and function, curtailing life-expectancy. Patients may experience angina and myocardial ischemia. However, the mechanisms underlying these changes are poorly understood. METHODS. A cross-sectional, case-control design of coronary pathophysiology (in vivo and ex vivo) in IPAH. Patients with IPAH (Group-1.1) undergoing clinically indicated right heart catheterization were prospectively enrolled. Participants underwent functional testing during coronary angiography using a dual pressure/temperature-sensitive guidewire. Cardiovascular magnetic resonance measured left and right ventricular mass and function. Autopsy cardiac tissues from end-stage PAH (Group-1) and control individuals were analyzed for right ventricular pathophysiology. RESULTS. Eleven participants with IPAH and 15 control participants completed the protocol (IPAH: 45±15 years, 73% female; controls: 58.3±9.1 years, 73% female). 73% (n=8) of IPAH patients had an elevated index of microcirculatory resistance (IMR >25) and 55% (n=6) had reduced coronary flow reserve (CRF <2.0). The mean IMR was significantly higher in IPAH participants (39.2±27.0 vs. 15.3±5.0, p=0.002) whereas mean CFR was lower (2.8±2.1 vs. 4.0±1.4; p=0.077). Paired right coronary artery/ventricular measurements (n=6) revealed IMR positively correlated with right ventricular mass (r=0.91, p=0.12), and negatively with CFR (r=-0.82, p=0.046). Compared to controls (n=5), PAH participants (n=4) had reduced right ventricular capillary density (111±18 vs. 167±20, p=0.032), increased cardiomyocyte area (383±118μm2 vs. 231±61μm2, p=0.0390), and increased mural area in small pre-capillary arterioles (127±10μm2 vs. 107±20μm2, p=0.041). CONCLUSIONS. Coronary microvascular dysfunction is prevalent in IPAH and correlates with increased right ventricular mass. Histopathology revealed vascular rarefaction and remodeling of pre-capillary arterioles. The clinical significance merits prospective evaluation. Invasive coronary function testing was feasible and safe in IPAH, providing a platform to assess therapeutic impacts on cardiac microvascular function.
Authors
Erin Boland, Michael G. Freeman, David S. Corcoran, Thomas J. Ford, Barry Hennigan, Damien Collison, Aida Llucià-Valldeperas, Frances S. de Man, Kanarath P. Balachandran, Martin Johnson, Colin Church, Colin Berry
Abstract
The central nervous system (CNS) parenchyma has conventionally been believed to lack lymphatic vasculature, likely owing to a non-permissive microenvironment that hinders the formation and growth of lymphatic endothelial cells (LECs). Recent findings of ectopic expression of LEC markers including prospero homeobox 1 (PROX1), a master regulator of lymphatic differentiation, and the vascular permeability marker plasmalemma vesicle–associated protein (PLVAP) in certain glioblastomas (GBM) and brain arteriovenous malformations have prompted investigation into their roles in cerebrovascular malformations, tumor environments, and blood-brain barrier (BBB) abnormalities. To explore the relationship between ectopic LEC properties and BBB disruption, we used endothelial cell–specific Prox1 overexpression mutants. When induced during embryonic stages of BBB formation, endothelial Prox1 expression induces hybrid blood-lymphatic phenotypes in the developing CNS vasculature. This effect is not observed when Prox1 is overexpressed during postnatal BBB maturation. Ectopic Prox1 expression leads to significant vascular malformations and enhanced vascular leakage, resulting in BBB disruption when induced during both embryonic and postnatal stages. Mechanistically, PROX1 downregulates critical BBB-associated genes, including β-catenin and claudin-5, which are essential for BBB development and maintenance. These findings suggest that PROX1 compromises BBB integrity by negatively regulating BBB-associated gene expression and Wnt/β-catenin signaling.
Authors
Sara González-Hernández, Ryo Sato, Yuya Sato, Chang Liu, Wenling Li, Zulfeqhar A. Syed, Chengyu Liu, Sadhana Jackson, Yoshiaki Kubota, Yoh-suke Mukouyama
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