Biology subjects

Yang, L. V.

Publications and source records attributed to Yang, L. V..

10 recordsLinked to original sources

bioRxiv2026

Spatial multi-omics reveals novel vascular adipocyte and B cell biology in human abdominal aortic aneurysm

Objective: Perivascular Adipose Tissue (PVAT), tertiary lymphoid structures (TLS), and the B lymphocytes they harbor have been implicated in regulating vascular diseases, including abdominal aortic aneurysm (AAA). Yet, the relationship of adipose tissue to TLS and B cell responses is poorly understood. Approach and Results: Here, we used a multi-omic approach to rigorously define the landscape of human AAA and characterize the adipocyte and TLS microenvironment with regard to B-cell responses to vascular antigens in human AAA and control non-aneurysmal abdominal aortas. Single-nucleus and single-cell RNA sequencing identified transcripts for lipogenesis, lipolysis, extracellular remodeling, haptotactic and chemotactic factors, with potential to recruit CD44+ leukocytes within AAAs. Immunohistology and Visium HD spatial transcriptomics revealed that at least two adipocyte types exist: one in the PVAT and another as isolated clusters in the medial-adventitial region in human AAAs but not in control aortas. Further characterization of these medial-adventitial adipocytes in the AAAs showed close association with TLSs. Mature TLSs recapitulated the organization of functional secondary lymphoid structures, with multiple B-cell follicles clustered to form a nodular structure partly covered by a layer of smooth muscle cells. The TLSs harbored isotype-switched B cells expressing IgG1, IgG3, or IgA, with dominant kappa chain usage and abundant IgG antibodies to aortic wall. Myeloid cells in AAA were implicated in promoting B cell effects, as they were the primary producers of B-cell activating factor (BAFF), a cytokine that promotes B cell infiltration, survival, and function. Conclusion: Altogether, our results support a novel model in which new adipocytes in the medial-adventitial layer produce factors that promote early TLS formation, and BAFF produced by myeloid cells promotes the survival and maturation of vascular wall-antigen-exposed B cells, leading to mature TLS formation, production of antibodies to AAA antigens, fueling inflammation and AAA growth.

immunology↗

bioRxiv2026

CREB/CRTC2-Induced GPR65 Orchestrates Th17 Metabolic Fitness and Pathogenic Effector Function

GPR65 has been shown to be a critical regulator of Th17 cell pathogenicity. Loss of GPR65 in mice results in a decrease in Th17 cells and reduced susceptibility to a mouse model of multiple sclerosis. The CREB/CRTC2 pathway has emerged as an important regulator of immune function. We have previously shown that the CREB/CRTC2 pathway modulates autoimmune disease by promoting differentiation of Th17 cells. In this study we performed RNA-seq to identify Th17 genes regulated by the CREB/CRTC2 pathway. Our RNA-seq analysis led us to uncover the first mechanism of regulation of the orphan receptor GPR65 by the CREB/CRTC2 pathway. We show that GPR65 is a target of the CREB/CRTC2 pathway through expression studies and chromatin immunoprecipitation. In addition, we show that targeting GPR65 with small molecules alters the expression of IL-17A. Understanding the regulation of GPR65 will be crucial in developing small molecules to treat patients with Th17 cell-mediated disorders.

immunology↗

bioRxiv2026

Intestinal intraepithelial lymphocyte migration and tissue homeostasis are dictated by Gα13

Intestinal intraepithelial lymphocytes (IEL), including conventional CD8{beta} T resident memory (Trm) cells and unconventional CD8 T cells, promote tissue integrity. Here, we studied the G-protein coupled receptor signals regulating IEL positioning, homeostasis, and function. Deficiency in heterotrimeric G-protein subunit G13 or its effector Arhgef1 caused an intestine-specific loss of all types of CD8+ TCR{beta} and TCR{gamma}{delta} IEL. G13-deficient IEL exhibited restricted intraepithelial movement and impaired maturation. Induction of intestinal CD8{beta}+ Trm upon infection was intact in the absence of G13-signaling, but the cells had poor access to the villous niche and defective survival that could be rescued by increasing TGF{beta}+ or interleukin (IL)15. In vivo CRISPR/Cas9 screening identified GPR132 as a G13-coupled receptor that regulates CD8{beta}+ IEL homeostasis and migration to lysophosphatidylcholine. Mice bearing G13-deficient T cells suffered more severe colitis and increased colorectal tumor growth. The selective requirement for G13-signaling for IEL positioning and survival in the villous niche has implications for therapeutic intervention.

immunology↗

bioRxiv2024

The GPR4 antagonist NE-52-QQ57 increases survival, mitigates the hyperinflammatory response and reduces viral load in SARS-CoV-2-infected K18-hACE2 transgenic mice

COVID-19 (Coronavirus disease 19) is caused by infection with SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) in the respiratory system and other organ systems. Tissue injuries resulting from viral infection and host hyperinflammatory responses may lead to moderate to severe pneumonia, systemic complications, and even death. While anti-inflammatory agents have been used to treat patients with severe COVID-19, their therapeutic effects are limited. GPR4 (G protein-coupled receptor 4) is a pro-inflammatory receptor expressed on vascular endothelial cells, regulating leukocyte infiltration and inflammatory responses. In this study, we evaluated the effects of a GPR4 antagonist, NE-52-QQ57, in the SARS-CoV-2-infected K18-hACE2 transgenic mouse model. Our results demonstrated that GPR4 antagonist treatment increased the survival rate in this severe COVID-19 mouse model. The inflammatory response, characterized by proinflammatory cytokines and chemokines, was reduced in the GPR4 antagonist group compared with the vehicle group. Additionally, both SARS-CoV-2 RNA copy numbers and infectious viral titers in the mouse lung were decreased in the GPR4 antagonist group. The percentage of SARS-CoV-2 antigen-positive mouse brains was also decreased in the GPR4 antagonist group compared to the vehicle group. Furthermore, the GPR4 antagonist inhibited SARS-CoV-2 propagation in Vero E6 cells. Together, these results suggest that GPR4 antagonism may be explored as a novel approach for the treatment of COVID-19 and other similar viral diseases.

pharmacology and toxicology↗

bioRxiv2024

Activation of the proton-sensing GPCR, GPR65 on fibroblast-like synoviocytes contributes to inflammatory joint pain.

Inflammation is associated with localised acidosis, however, attributing physiological and pathological roles to proton-sensitive receptors is challenging due to their diversity and widespread expression. Here, agonists of the proton-sensing GPCR, GPR65, were systematically characterised. The synthetic agonist BTB09089 (BTB) recapitulated many proton-induced signalling events and demonstrated selectivity for GPR65. BTB was used to show that GPR65 activation on fibroblast-like synoviocytes (FLS), cells that line synovial joints, results in the secretion of pro-inflammatory mediators capable of recruiting immune cells and sensitising sensory neurons. Intra-articular injection of BTB resulted in GPR65-dependent sensitisation of knee-innervating neurons and nocifensive behaviours in mice. Stimulation of GPR65 on human FLS also triggered the release of inflammatory mediators and synovial fluid samples from human osteoarthritis patients were shown to activate GPR65. These results suggest a role of GPR65 in mediating cell-cell interactions that drive inflammatory joint pain in both mice and humans.

neuroscience↗

bioRxiv2023

GPR4 knockout attenuates intestinal inflammation and forestalls the development of colitis-associated colorectal cancer in murine models

GPR4 is a proton-sensing G protein-coupled receptor highly expressed in vascular endothelial cells and has been shown to potentiate intestinal inflammation in murine colitis models. Herein, we evaluated the proinflammatory role of GPR4 in the development of colitis-associated colorectal cancer (CAC) using the dextran sulfate sodium (DSS) and azoxymethane (AOM) mouse models in wild-type and GPR4 knockout mice. We found GPR4 contributed to chronic intestinal inflammation and heightened DSS/AOM-induced intestinal tumor burden. Tumor blood vessel density was markedly reduced in mice deficient in GPR4 which correlated with increased tumor necrosis and reduced tumor cell proliferation. These data demonstrate GPR4 ablation alleviates intestinal inflammation and reduces tumor angiogenesis, development, and progression in the AOM/DSS mouse model. Author summaryInflammatory bowel disease (IBD), including ulcerative colitis and Crohns disease, is a debilitating condition with chronic inflammation in the digestive tract. Patients with IBD are at higher risk of developing colitis-associated colorectal cancer (CAC), compared with the general population. The etiology of IBD is not well understood, but both genetic and environmental factors have been implicated. In this study, we investigated the role of the pH-sensing GPR4 receptor in colitis and CAC using the DSS and AOM induced mouse models. GPR4 knockout alleviated intestinal inflammation, reduced tumor angiogenesis, and impeded CAC development. Our data suggest that inhibition of GPR4 may be explored as a potential therapeutic approach for IBD treatment and CAC prevention.

cancer biology↗

bioRxiv2019

The proton-sensing GPR4 receptor regulates paracellular gap formation and permeability of vascular endothelial cells

Tissue acidosis can be a consequence of numerous disease states including stroke, myocardial infarction, limb ischemia, and inflammation. Blood vessels existing in the affected tissues are associated with the progression of acidosis-related diseases. However, the mechanisms by which endothelial cells (ECs) lining the affected blood vessels sense and respond to an acidic microenvironment remain largely unclear. We investigated the functional effects of the proton-sensing G protein-coupled receptor GPR4 in acidosis-induced endothelial inflammation. GPR4 is highly expressed in ECs and known to regulate EC inflammation and endoplasmic reticulum stress responses within acidic microenvironments. Using genetic and pharmacological approaches, we demonstrate that GPR4 activation by acidosis increases EC paracellular gap formation and permeability. We further demonstrate that GPR4-mediated paracellular gap formation is dependent on the G12/13 signaling pathway. To assess the functional role of GPR4 in the inflammatory response in vivo, we utilized an acute hindlimb ischemia-reperfusion mouse model. We demonstrate that both genetic deletion and pharmacological inhibition of GPR4 reduce tissue edema, exudate formation, endothelial adhesion molecule expression, and leukocyte infiltration in the inflamed tissue. Collectively, these data suggest GPR4/G12/13 signaling mediates acidosis-induced endothelial paracellular gap formation and permeability. This study implicates GPR4 as a candidate therapeutic target for the remediation of inflammation and tissue edema.

cell biology↗

bioRxiv2019

Pharmacological inhibition of GPR4 remediates intestinal inflammation in a mouse colitis model

Inflammatory bowel disease (IBD) is characterized by chronic, recurring inflammation of the digestive tract. Current therapeutic approaches are limited and include biologics and steroids such as anti-TNF monoclonal antibodies and corticosteroids, respectively. Significant adverse drug effects can occur for chronic usage and include increased risk of infection in some patients. GPR4, a pH-sensing G protein-coupled receptor, has recently emerged as a potential therapeutic target for intestinal inflammation. We have assessed the effects of a GPR4 antagonist, 2-(4-((2-Ethyl-5,7-dimethylpyrazolo[1,5-a]pyrimidin-3-yl)methyl)phenyl)-5-(piperidin-4-yl)-1,3,4-oxadiazole (GPR4 antagonist 13, also known as NE 52-QQ57) in the dextran sulfate sodium (DSS)-induced acute colitis mouse model. The GPR4 antagonist 13 inhibited intestinal inflammation. The clinical parameters such as body weight loss and fecal score were reduced in the GPR4 antagonist 13 treatment group compared to vehicle control. Macroscopic disease indicators such as colon shortening, splenic expansion, and mesenteric lymph node enlargement were all reduced in severity in the GPR4 antagonist 13 treated mice. Histopathological features of active colitis were alleviated in GPR4 antagonist 13 treatment groups compared to vehicle control. Finally, inflammatory gene expression in the colon tissues and vascular adhesion molecule expression in the intestinal endothelia were attenuated by GPR4 antagonist 13. Our results indicate that GPR4 antagonist 13 provides a protective effect in the DSS-induced acute colitis mouse model, and inhibition of GPR4 can be explored as a novel anti-inflammatory approach.

pharmacology and toxicology↗

bioRxiv2018

TDAG8 (GPR65) Inhibits Intestinal Inflammation in the DSS-Induced Experimental Colitis Mouse Model

T cell death-associated gene 8 (TDAG8, also known as GPR65) is a proton-sensing G protein-coupled receptor (GPCR) predominantly expressed in immune cells. Genome-wide association studies identify TDAG8 as a susceptibility candidate gene linked to several human inflammatory diseases including inflammatory bowel disease (IBD), asthma, spondyloarthritis, and multiple sclerosis. In this study, our results demonstrate that mice deficient of TDAG8 exhibited more severe inflammatory phenotypes than wild-type mice in a chronic dextran sulfate sodium (DSS)-induced colitis mouse model. Several disease parameters, such as diarrhea, colon shortening, fibrosis, histopathological score, and mesenteric lymph node enlargement were aggravated in TDAG8-null mice in comparison to wild-type mice treated with DSS. Increased leukocyte infiltration and myofibroblast expansion were observed in colonic tissues of DSS-treated TDAG8-null mice. These changes may represent a cellular basis of the observed exacerbation of intestinal inflammation and fibrosis in these mice. In line with high expression of TDAG8 in infiltrated leukocytes, real-time RT-PCR revealed that TDAG8 mRNA expression was increased in inflamed intestinal tissue samples of IBD patients when compared to normal intestinal tissues. Altogether, our data demonstrate that TDAG8 suppresses intestinal inflammation and fibrosis in the chronic DSS-induced colitis mouse model, suggesting potentiation of TDAG8 with agonists may have anti-inflammatory therapeutic effects in IBD.

pathology↗

bioRxiv2017

Contextual Tumor Suppressor Function Of T Cell Death-Associated Gene 8 (TDAG8) In Hematological Malignancies

Key points1. TDAG8 (GPR65) gene expression is down-regulated in hematological malignancies.\n\n2. Restoration of TDAG8 gene expression in blood cancer cells suppresses tumor growth and metastasis.\n\nAbstractExtracellular acidosis is a condition found within the tumor microenvironment due to inadequate blood perfusion, hypoxia, and altered tumor cell metabolism. Acidosis has pleiotropic effects on malignant progression; therefore it is essential to understand how acidosis exerts its diverse effects. In this study a bioinformatics analysis revealed the expression of the proton sensing G-protein-coupled receptor TDAG8 is significantly reduced in human blood cancers in comparison to normal blood cells. To understand how TDAG8 functions in hematological malignancies, TDAG8 expression was restored in U937 acute myeloid leukemia cells and other blood cancer cells. It was discovered that severe acidosis, pH 6.4, inhibited U937 cell proliferation while mild acidosis, pH 6.9, stimulated cell proliferation. However, restoring TDAG8 gene expression modulated the U937 cell response to mild extracellular acidosis and physiological pH by reducing cell proliferation. Tumor xenograft experiments further revealed that restoring TDAG8 expression in U937 and Ramos cancer cells reduced tumor growth. It was also shown U937 cells with restored TDAG8 expression attached less to Matrigel, migrated slower toward a chemoattractant, and metastasized less in severe combined immunodeficient mice. These effects correlated with a reduction in c-myc oncogene expression. The mechanistic investigation indicated that G13/RhoA signaling arbitrated the TDAG8-mediated c-myc oncogene repression in response to acidosis. Overall, this study provides compelling data to support the concept that TDAG8 functions as a contextual tumor suppressor in hematological malignancies and sensitizes blood cancer cells to acidotic stress.

cancer biology↗