Vascular biology
Abstract
We generated a comparative spatial proteomic atlas of the human and mouse retina using a highly multiplexed immunohistochemistry technique called iterative bleaching extends multiplexity (IBEX). We refined the IBEX workflow by integrating an antibody dissociation option alongside chemical bleaching. This dual strategy enabled removal of the entire antibody complex, permitting the flexible use of antibodies from the same host species across iterative cycles. We coupled this workflow with super-resolution imaging via deconvolution and applied it to the retina of healthy humans and WT mice and the Crb1rd8 mouse model. We successfully imaged over 25 protein markers on human and mouse tissue sections, generating spatial atlases of the major retinal cell populations. Cross-species protein expression was compared to scRNA-seq datasets to identify protein and transcript disparities. Super-resolution IBEX delineated the ultrastructural features of the outer limiting membrane (OLM), identifying CD44 as a core structural component tightly colocalized with a highly organized F-actin belt within Müller glial endfeet. Using the Crb1rd8 mouse model, disruption of this complex was spatially associated with rosette formation and OLM structural failure. In summary, spatial proteomic atlases of the human and mouse retina were used to reveal insights into the arrangement of major retinal cell populations and OLM structure.
Authors
Yuxuan Meng, Jakub Kubiak, Zuzanna Dzieniak, Lorna Fowler, Rose Avient, Jason Hopley, Linyulong Li, Chaoran Li, Yuan Tian, Bruno Charbit, Colin J. Chu
Abstract
Vascularized skins were 3D printed using single donor human fibroblasts, pericytes, keratinocytes, and endothelial cells (ECs), the latter either unmodified (WT-ECs) or deleted of MHC molecules (KO-ECs). Adult MISTRG6 immunodeficient mice neonatally inoculated with adult human hematopoietic stem cells (HSCs) received printed skin allogeneic to the HSCs and were boosted 3 weeks after grafting with human PBMCs autologous to the HSCs. HSC inoculation alone produced low levels of circulating human myeloid and lymphoid cells without affecting grafts; PBMC boosting dramatically increased circulating human CD4+ T cells and boosted CD8+ T cells only in mice with WT-EC grafts. These grafts became infiltrated by human macrophages, dendritic cells, CD4+ and CD8+ T cells and showed evidence of rejection. Shared T cell clones were present in skin and spleen. KO-EC grafts had minimal infiltration of graft or spleen without rejection, despite MHC molecule expression on other graft cell types.
Authors
Zuzana Tobiasova, Esen Sefik, Lingfeng Qin, Jennifer M. McNiff, Gwendolyn Davis, Richard A. Flavell, W. Mark Saltzman, Jordan S. Pober
Abstract
Systemic sclerosis (SSc) is characterized by fibrosis and vasculopathy affecting the skin and internal organs, leading to multiorgan dysfunction. Injury of microvascular endothelial cells (ECs) in SSc impairs blood flow and causes tissue ischemia, leading to vascular complications such as Raynaud’s, digital ulcers, and pulmonary hypertension (PH). PH in SSc presents as group 1 pulmonary arterial hypertension or as group 3 PH related to hypoxia and interstitial lung disease (ILD), both major causes of mortality. Analysis of multiome data from SSc ILD-PH lungs inferred transcription factors regulating EC phenotype, including FOSL2. Overexpression of FOSL2 in transgenic mice (Fosl2tg) leads to vascular changes mirroring human SSc-PH, such as intimal thickening and fibrosis. scRNA-Seq analysis of altered EC gene expression in Fosl2tg mice showed strong overlap with altered EC gene expression in SSc-ILD-PH. Overlapping as well as discrete EC gene expression in Sugen/hypoxia- and hypoxia-treated mice suggested that FOSL2 regulates both hypoxia-dependent and -independent pathways in Fosl2tg mice and SSc-ILD-PH. A deep learning model, ChromBPNet, inferred increased AP-1 binding at base pair resolution in SSc-ILD-PH ECs, and binding to the same motifs was found upon FOSL2 overexpression in primary vascular ECs, highlighting FOSL2’s key role in driving the pathological changes seen in SSc-ILD-PH.
Authors
Rithika Behera, Yuechen Zhou, Peter H. Gerges, Jingyu Fan, Tracy Tabib, Alyxzandria M. Gaydosik, Mengqi Huang, Jishnu Das, Elena Pachera, Amela Hukara, Ying Tang, Florian Renoux, Miranda Tai, Oliver Distler, Gabriela Kania, Stephen Y. Chan, Harinder Singh, Eleanor Valenzi, Robert Lafyatis
Abstract
Interscapular brown adipose tissue (iBAT), one of the most vascularized tissues in the body, exemplifies the intricate crosstalk between the vascular system and adipocytes. BAT is known to secrete abundant exosomes into circulation, while exosomes are known to play a key role in vascular remodeling and cell migration. However, whether BAT-derived exosomes (BATexos) modulate peripheral vasculature remains unclear. Here, we report that BATexos promoted peripheral angiogenesis and vascular repair. Among their cargo, miR-378a-3p was highly enriched and identified as a key mediator of endothelial angiogenic function. The overexpression of miR-378a-3p in endothelial cells substantially promoted cell migration and tube formation. Conversely, inhibition of exosome secretion from BAT impaired vascular repair and delayed wound healing. Mechanistically, miR-378a-3p directly targeted the phosphatase and tensin homolog (Pten), thereby activating the PI3K-AKT signaling pathway. Liposomes encapsulating miR-378 mimics promoted angiogenesis and accelerated wound healing in a diabetic mouse model. Collectively, this study uncovers BAT-derived miR-378a-3p as a key regulator of vessel regeneration and tissue repair following injury, offering new therapeutic potential for treating vascular complications in metabolic disease.
Authors
Hongyan Deng, Yuyu Xie, Jiadai Liu, Jing Ge, Qianqian Kang, Rui He, Zhihan Wang, Xuemin Peng, Zengzhe Zhu, Wenshe Wang, Yulian Liu, Ronghui Gao, Ruping Pan, Min Yang, Yong Chen
Abstract
Giant cell aortitis (GCA) is an inflammatory disease of the aortic wall with a characteristic giant cell pattern on pathology and can lead to life-threatening aortic aneurysm and dissection. Pathogenic GCA mechanisms underlying aortic inflammation and persistence remain elusive. Here, we demonstrate the complexity of medial layer destruction and immune cell infiltration in clinical granulomatous GCA and lymphoplasmacytic IgG4-related aortitis samples using imaging-based gene expression profiling. Single-cell spatial profiling revealed aortic wall remodeling in the GCA aortas, highlighting substantial phenotypic modulation in stromal cells, including vascular smooth muscle cells (SMCs) and fibroblasts. Specifically, we observed the expansion of stromal cells expressing Tenascin-C (TNC) mRNA and spatially refined TNC accumulation in lesion areas. We confirmed these findings histologically using diseased aortas resected from individuals with giant cell arteritis and clinically isolated aortitis. Mechanistically, our data suggest that TNC promotes a proinflammatory phenotype in primary human SMCs, elevating IL-6 levels partially through the TLR4/NF-κB pathway. IL-6 signaling propagates the proinflammatory loop by activating STAT3. Pharmacological blockade of the IL-6 receptor using tocilizumab alleviated the TNC-driven proinflammatory phenotype. We propose that TNC acts as a local catalyst of inflammatory disease persistence mainly via IL-6 signaling activation and offers a potential avenue for sustained disease remission.
Authors
Hui Shi, Ying Tang, Jing Li, Ora Gewurz-Singer, Bo Yang, Dogukan Mizrak
Abstract
Subendothelial retention of cholesterol-rich apolipoprotein-B-containing lipoproteins drives atherosclerotic arterial disease. In peripheral interstitial fluid from patients with type 2 diabetes (T2D), levels of such particles have been shown to be paradoxically reduced relative to those in serum, presumably reflecting their increased retention within the arterial wall. To identify possible mechanisms involved in lipoprotein retention in T2D, we obtained serum and skin blister fluid from such patients and matched controls, together with skin biopsies in a subset of individuals. In T2D, smaller LDL and VLDL remnant particles were more prominent in serum, but not in interstitial fluid, reflecting their enhanced vascular entrapment. The interstitial-fluid-to-serum ratio of apolipoprotein-B was 58% lower in T2D than in controls (0.14 vs 0.33), concomitant with increased susceptibility for LDL binding to proteoglycans. The most marked differences were seen in patients with clinically evident cardiovascular disease. The degree of transvascular retention was positively related to the propensity of isolated serum LDL to bind aortic proteoglycans, both in T2D and in controls. Skin unesterified cholesterol levels were higher in T2D patients relative to healthy controls. With aging, both proteoglycan binding and apparent vascular retention of LDL increased in controls, but not in T2D, indicating that these mechanisms may also be relevant for atherogenesis in non-diabetic individuals.
Authors
Pär Björklund, Jennifer Härdfeldt, Lauri Äikäs, Sara Straniero, Minna Holopainen, Katariina Öörni, Mats J. Rudling, Bo Angelin
Abstract
Hypoxia critically restricts the effectiveness of immunotherapy in triple-negative breast cancer (TNBC). Comprehensive bioinformatics analyses demonstrated that highly hypoxic TNBC tumors exhibited elevated T cell exhaustion, increased immune checkpoint molecule expression, and diminished responsiveness to immune checkpoint blockade (ICB). Consequently, strategies aimed at alleviating tumor hypoxia may effectively augment ICB therapy. Although ultrasound-targeted microbubble cavitation (UTMC) has been shown to reduce tumor hypoxia, the precise molecular mechanisms remain unclear. Here, we provided evidence that UTMC activated endothelial nitric oxide synthase (eNOS) through G protein–coupled signaling, resembling pathways induced by fluid shear stress. UTMC-induced eNOS activation was largely Ca²⁺-dependent and resulted in increased nitric oxide production. Enhanced nitric oxide generation was associated with improved tumor perfusion and reduced hypoxia. Combining UTMC with anti–PD-L1 therapy markedly improved the tumor immune microenvironment, characterized by increased CD8+ T cell infiltration, reduced T cell exhaustion, diminished regulatory T cell infiltration, increased macrophage polarization from an M2 to M1 phenotype, and elevated production of pro-inflammatory cytokines. Collectively, our findings identified UTMC as a promising adjunctive therapeutic approach to mitigate hypoxia and enhance the efficacy of anti–PD-L1 immunotherapy in TNBC. These results support further translational evaluation of UTMC-based combination strategies in hypoxic TNBC.
Authors
Zhiyu Zhao, Li Ba, Siwei Li, Jianxin Wang, Yuzhou Luo, Sihan Wang, Yan Jin, Changjun Wu
Abstract
The RhoBTB1-Cullin3 (CUL3) pathway in smooth muscle cells (SMCs) controls the ubiquitination and proteasomal degradation of target proteins that regulate vasodilation, vasoconstriction, and the actin cytoskeleton, and through this blood pressure (BP) and arterial stiffness. Using proximity labelling coupled with mass spectrometry in A7R5 SMCs, we identified proteins which bound to the C-terminal half of RhoBTB1 which functions as an adapter to deliver substrates to CUL3. We examined the physiological relevance of one of these substrates, RbFox2. Co-immunoprecipitation validated the interaction of RbFox2 with RhoBTB1. RbFox2 expression was elevated in response to inhibition of the ubiquitination-proteasomal pathway, CUL3-deficiency, and RhoBTB1 inhibition by either siRNA or angiotensin II (ANG). RbFox2 was ubiquitinated in a RhoBTB1- and CUL3-dependent manner suggesting its regulation through the RhoBTB1-CUL3-dependent ubiquitin-proteasome pathway. Inhibition of RbFox2 impaired the actin cytoskeleton in A7R5 cells and in primary SMC from RbFox2Flox/Flox (RbFox2F/F) mice and decreased the levels of globular and filamentous actin. ANG increased BP and arterial stiffness of RbFox2F/F mice, but the progression of arterial stiffness was halted after SMC-specific RbFox2 deletion despite a continued rise in BP. We conclude that RhoBTB1 and RbFox2 are important regulators of arterial stiffness through a mechanism that influences cytoskeletal integrity.
Authors
Gaurav Kumar, Nisita Chaihongsa, Daniel T. Brozoski, Daria Golosova, Ibrahim Vazirabad, Ko-Ting Lu, Kelsey K. Wackman, Ravi K. Singh, Curt D. Sigmund
Abstract
β-arrestins are ubiquitously expressed cytosolic adaptor proteins that regulate G protein-coupled receptor-dependent and -independent pathways essential for numerous physiological functions. This study investigated the role of β-arrestin1 and -2 in embryonic lymphatic vessel development and survival by generating and characterizing mice with lymphatic, tamoxifen-inducible loss of the genes encoding β-arrestin-1 and -2 (Arrb1/2ΔiLEC). At embryonic day15.5 (E15.5), Arrb1/2ΔiLEC embryos exhibit profound hydrops fetalis and increased embryonic mortality compared to control Arrb1/2fl/fl embryos. Edematous Arrb1/2ΔiLEC embryos, which were more often represented by the female sex, showed growth restriction and decreased lymphatic endothelial cell (LEC) proliferation in the jugular lymphatic sac compared to controls. In vitro knockdown of β-arrestin1 in LECs increased proliferation and increased activation of AKT, while knockdown of β-arrestin2 decreased proliferation and decreased activation of both ERK and CREB. Arrb1/2ΔiLEC embryos also exhibited dilated dermal lymphatics with decreased continuous VE-Cadherin adherens junctions compared to controls. These results were recapitulated in vitro in β-arrestin1 and/or -2 knockdown human LECs, which showed a decrease in membrane VE-Cadherin and β-catenin levels, and prevention of adrenomedullin-induced linearization of VE-cadherin at endothelial cell–cell junctions. Collectively, these results demonstrate that loss of β-arrestin1/2 in lymphatics causes hydrops fetalis, mid-gestational growth arrest and embryonic demise associated with reduced LEC proliferation and disrupted VE-Cadherin adherens junctions.
Authors
Yanna Tian, D. Stephen Serafin, Monserrat Avila-Zozaya, Alyssa M. Tauro, Natalie M. Torres-Valle, Bryan M. Kistner, Danielle M. Dy, Elizabeth S. Douglas, Kathleen M. Caron
Abstract
Thoracic Aortic Aneurysm and Dissections (TAAD) is a progressive dilation of the aortic wall associated with degradation of the extracellular matrix (ECM), cystic medial degeneration, smooth muscle cell (SMC) dysfunction, and rarefaction. TAAD etiology and pathogenesis suggest that alteration of mechanical force propagation may contribute to SMC dysfunction. This study aims to determine the role of SMC focal adhesion proteins, which are key components of force transmission, in TAAD pathogenesis. scRNAseq analysis of human TAA aortas showed reduced expression of intracellular focal adhesion components, including PTK2 (FAK), VCL, ILK, and TES transcripts, in SMCs. Additionally, protein levels of FAK, ILK, and VCL were decreased in the aorta of patients with TAA. SMC-specific Ptk2, Vcl, and Ilk knockout mice treated with β-Aminopropionitrile (BAPN) exhibited increased mortality, aortic dilation, ECM breakdown, and SMC loss. Mechanistically, knocking down FAK, ILK, and VCL exacerbated gliotoxin-induced SMC anoikis, whereas overexpressing full-length wild-type (WT) and dead-kinase FAK conferred resistance to apoptosis and cell detachment, indicating that FAK's protective effects depend on its expression rather than its enzymatic activity. Inhibition of FAK kinase activity did not affect SMC apoptosis in vitro or aortic dilation in vivo. Our findings demonstrated that the expression of focal adhesion proteins protects against TAAD progression and SMC anoikis independently of FAK kinase activity.
Authors
Zhenyuan Zhu, Mingjun Liu, Jianxin Wei, Deepa Suryanarayan, Parya Behzadi, Robert Edgar, Julie A. Phillippi, Cynthia St. Hilaire, Cristina Espinosa-Diez, Delphine Gomez
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