Biology subjects

Xiang, J. Z.

Publications and source records attributed to Xiang, J. Z..

10 recordsLinked to original sources

bioRxiv2025

Single-cell transcriptomics reveals targeted modulation of inflammatory repertoire by SOCE blockers

Store-operated calcium entry (SOCE) plays a critical role in regulating intracellular calcium signaling and is essential for immune cell functions. SOCE blockade with pyrazole derivative BTP2 has been explored as an anti-inflammatory strategy in preclinical models and Zegocractin (CM4620) is being investigated in Phase 2 clinical trials as an immunoregulatory agent. However, the mode of action and differential effects of SOCE blockade on diverse immune cell types remain largely unknown, limiting the precision of current therapeutic applications. Here, we used multiplexed single-cell RNA sequencing to investigate the effects of two prototypic SOCE blockers, BTP2 and CM4620, on polyclonally-stimulated, normal human peripheral blood mononuclear cells (PBMCs). The data revealed that SOCE blockade suppresses the expression of cytotoxicity-associated genes in CD8{square} effector T cells and natural killer (NK) cells, restoring them to levels comparable to those in unstimulated cells. Strikingly, SOCE blockade preserved activation-induced expression of anti-inflammatory genes in CD4{square} regulatory T cells, maintaining their tolerance phenotype even after SOCE blockade. These findings suggest that SOCE blockers modulate immune responses with greater selectivity than conventional immunosuppressants by reducing cytotoxicity while preserving tolerance-associated pathways, highlighting their potential for managing immune-mediated conditions, including organ transplantation. KEY POINTSO_LISOCE blockers BTP2 and CM4620 reduce cytotoxic gene expression in CD8{square} T cells and NK cells. C_LIO_LISOCE blockade preserves anti-inflammatory programs in CD4{square} Tregs, supporting selective immune modulation. C_LI

immunology↗

bioRxiv2024

Human Vascularized Macrophage-Islet Organoids to Model Immune-Mediated Pancreatic β cell Pyroptosis upon Viral Infection

There is a paucity of human models to study immune-mediated host damage. Here, we utilized the GeoMx spatial multi-omics platform to analyze immune cell changes in COVID-19 pancreatic autopsy samples, revealing an accumulation of proinflammatory macrophages. Single cell RNA-seq analysis of human islets exposed to SARS-CoV-2 or Coxsackievirus B4 (CVB4) viruses identified activation of proinflammatory macrophages and {beta} cell pyroptosis. To distinguish viral versus proinflammatory macrophage-mediated {beta} cell pyroptosis, we developed human pluripotent stem cell (hPSC)-derived vascularized macrophage-islet (VMI) organoids. VMI organoids exhibited enhanced marker expression and function in both {beta} cells and endothelial cells compared to separately cultured cells. Notably, proinflammatory macrophages within VMI organoids induced {beta} cell pyroptosis. Mechanistic investigations highlighted TNFSF12-TNFRSF12A involvement in proinflammatory macrophage-mediated {beta} cell pyroptosis. This study established hPSC- derived VMI organoids as a valuable tool for studying immune cell-mediated host damage and uncovered mechanism of {beta} cell damage during viral exposure.

developmental biology↗

bioRxiv2023

Bcl-xL is translocated to the nucleus via CtBP2 to epigenetically promote metastasis

Besides its mitochondria-based anti-apoptotic role, Bcl-xL also travels to the nucleus to promote cancer metastasis by upregulating global histone H3 trimethyl Lys4 (H3K4me3) and TGF{beta} transcription. How Bcl-xL is translocated into the nucleus and how nuclear Bcl-xL regulates H3K4me3 modification are not understood. Here, we report that C-terminal Binding Protein 2 (CtBP2) binds Bcl-xL via its N-terminus and translocates Bcl-xL into the nucleus. Knockdown of CtBP2 by shRNA decreases the nuclear portion of Bcl-xL and reverses Bcl-xL-induced cell migration and metastasis in mouse models. Furthermore, knockout of CtBP2 suppresses Bcl-xL transcription. The binding between Bcl-xL and CtBP2 is required for their interaction with MLL1, a histone H3K4 methyltransferase. Pharmacologic inhibition of MLL1 enzymatic activity reverses Bcl-xL-induced H3K4me3 and TGF{beta} mRNA upregulation as well as cell invasion. Moreover, cleavage under targets and release using nuclease (CUT&RUN) coupled with next generation sequencing reveals that H3K4me3 modifications are particularly enriched in the promotor region of genes encoding TGF{beta} and its signaling pathway in the cancer cells overexpressing Bcl-xL. Altogether, the metastatic function of Bcl-xL is mediated by its interaction with CtBP2 and MLL1.

cancer biology↗

bioRxiv2023

Transcriptional Activation of Regenerative Hematopoiesis via Vascular Niche Sensing

Transition between activation and quiescence programs in hematopoietic stem and progenitor cells (HSC/HSPCs) is perceived to be governed intrinsically and by microenvironmental co-adaptation. However, HSC programs dictating both transition and adaptability, remain poorly defined. Single cell multiome analysis divulging differential transcriptional activity between distinct HSPC states, indicated for the exclusive absence of Fli-1 motif from quiescent HSCs. We reveal that Fli-1 activity is essential for HSCs during regenerative hematopoiesis. Fli-1 directs activation programs while manipulating cellular sensory and output machineries, enabling HSPCs co-adoptability with a stimulated vascular niche. During regenerative conditions, Fli-1 presets and enables propagation of niche-derived Notch1 signaling. Constitutively induced Notch1 signaling is sufficient to recuperate functional HSC impairments in the absence of Fli-1. Applying FLI-1 modified-mRNA transduction into lethargic adult human mobilized HSPCs, enables their vigorous niche-mediated expansion along with superior engraftment capacities. Thus, decryption of stem cell activation programs offers valuable insights for immune regenerative medicine.

cell biology↗

bioRxiv2023

Vascular oxidative stress causes neutrophil arrest in brain capillaries, leading to decreased cerebral blood flow and contributing to memory impairment in a mouse model of Alzheimer's disease

INTRODUCTIONIn this study, we explore the role of oxidative stress produced by NOX2-containing NADPH oxidase as a molecular mechanism causing capillary stalling and cerebral blood flow deficits in the APP/PS1 mouse model of AD. METHODSWe inhibited NOX2 in APP/PS1 mice by administering a 10 mg/kg dose of the peptide inhibitor gp91-ds-tat i.p., for two weeks. We used in vivo two-photon imaging to measure capillary stalling, penetrating arteriole flow, and vascular inflammation. We also characterized short-term memory function and gene expression changes in cerebral microvessels. RESULTSWe found that after NOX2 inhibition capillary stalling, as well as parenchymal and vascular inflammation, were significantly reduced. In addition, we found a significant increase in penetrating arteriole flow, followed by an improvement in short-term memory, and downregulation of inflammatory gene expression pathways. DISCUSSIONOxidative stress is a major mechanism leading to microvascular dysfunction in AD, and represents an important therapeutic target.

neuroscience↗

bioRxiv2022

IL-12-expressing highly immunogenic recombinant modified vaccinia virus Ankara reprograms tumor-infiltrating myeloid cells to overcome immune resistance

Resistance to immune checkpoint blockade (ICB) remains a major obstacle in cancer immunotherapy. We rationally engineered a second-generation recombinant Modified Vaccinia virus Ankara (MQ833) by deleting viral immune-evasion genes (E3L, E5R, WR199) and incorporating Flt3L, OX40L, and matrix-anchored IL12. Intratumoral MQ833 elicited robust tumor regressions across multiple models, including ICB-resistant and MHC-I-deficient tumors. Single-cell RNA sequencing revealed extensive remodeling of the tumor microenvironment, characterized by neutrophil and monocyte recruitment and activation, M2 macrophage depletion, M1 polarization, and effector T-cell differentiation and proliferation. Conditional Ifnar1 knockout mice demonstrated that MQ833 efficacy requires type I interferon signaling in neutrophils, macrophages/monocytes, and T cells. Moreover, Nos2 deficiency impaired therapeutic efficacy, confirming iNOS myeloid cells as key effectors. Together, these findings show that MQ833 activates innate-adaptive IFN cross-talk to reprogram myeloid and T cells, defining a rationally designed viral immunotherapy capable of overcoming ICB resistance. GRAPHIC ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=179 SRC="FIGDIR/small/509429v2_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@496f37org.highwire.dtl.DTLVardef@124bd78org.highwire.dtl.DTLVardef@1134528org.highwire.dtl.DTLVardef@216da6_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2022

Adaptive Immune Landscape of T-Cell Mediated Rejection of Human Kidney Allografts

The frequently occurring T cell mediated rejection (TCMR) is a risk factor for allograft failure. Immunosuppressive therapy fails to reverse almost 40% of TCMRs occurring in human kidney allografts. A better understanding of the molecular mechanisms of TCMR and precision therapeutics may improve allograft longevity. We investigated adaptive immune landscape of TCMR by genome wide RNA sequencing of 34 prototypic kidney allograft biopsies from 34 adult recipients of human kidney allografts. Sixteen of the 34 biopsies were categorized as Banff TCMR and the remaining 18 as Banff Normal biopsies. Computational analysis identified higher intragraft abundance of the gene sets for key players of adaptive immune system in TCMR. TCMR allografts were characterized by, i) increased antigen processing and presentation and T cell receptor signaling, ii) increased memory T cells, Tregs, Th1, Th2 and Th17 subsets, iii) increased aerobic glycolysis of lymphocytes and reduced metabolic activity of graft parenchymal cells, iv) increased T cell inhibitory receptors and exhaustion markers, v) increased apoptosis and necroptosis, and vi) increased extracellular matrix remodeling, all in comparison to Normal biopsies. Our genome-wide transcriptomics provides an atlas of adaptive immune landscape of TCMR in human kidney allografts, help deduce molecular mechanisms and prioritization of therapeutic targets.

immunology↗

bioRxiv2021

Intratumoral delivery of engineered recombinant modified vaccinia virus Ankara express-ing Flt3L and OX40L generates potent antitumor immunity through activating the cGAS/STING pathway and depleting tumor-infiltrating regulatory T cells

Intratumoral (IT) delivery of immune-activating viruses can serve as an important strategy to turn "cold" tumors into "hot" tumors, resulting in overcoming resistance to immune checkpoint blockade (ICB). Modified vaccinia virus Ankara (MVA) is a highly attenuated, non-replicative vaccinia virus that has a long history of human use. Here we report that IT recombinant MVA (rMVA), lacking E5R encoding an inhibitor of the DNA sensor cyclic GMP-AMP synthase (cGAS), expressing a dendritic cell growth factor, Fms-like tyrosine kinase 3 ligand (Flt3L), and a T cell co-stimulator, OX40L, generates strong antitumor immunity, which is dependent on CD8+ T cells, the cGAS/STING-mediated cytosolic DNA-sensing pathway, and STAT1/STAT2-mediated type I IFN signaling. Remarkably, IT rMVA depletes OX40hi regulatory T cells via OX40L/OX40 interaction and IFNAR signaling. Taken together, our study provides a proof-of-concept for improving MVA-based cancer immunotherapy, through modulation of both innate and adaptive immunity. One Sentence SummaryIntratumoral delivery of recombinant MVA for cancer immunotherapy

immunology↗

bioRxiv2021

Vaccinia E5 is a major inhibitor of the DNA sensor cGAS

The DNA sensor cyclic GMP-AMP synthase (cGAS) is critical in host antiviral immunity. Vaccinia virus (VACV) is a large cytoplasmic DNA virus that belongs to the poxvirus family. How vaccinia virus antagonizes the cGAS-mediated cytosolic DNA-sensing pathway is largely unknown. In this study, we screened 82 vaccinia viral genes to identify potential viral inhibitors of the cGAS/Stimulator of interferon gene (STING) pathway. We discovered that vaccinia E5 is a virulence factor and a major inhibitor of cGAS that elicits proteasome-dependent cGAS degradation. E5 localizes to the cytoplasm and nuclei of infected cells. Cytosolic E5 triggers K48-linked ubiquitination of cGAS and proteasome-dependent degradation via interacting with cGAS. E5 itself also undergoes ubiquitination and degradation. Deleting the E5R gene from the Modified vaccinia virus Ankara (MVA) genome strongly induces type I IFN production by dendritic cells (DCs) and promotes DC maturation, thereby improving the immunogenicity of the viral vector.

microbiology↗

bioRxiv2020

Identification of Drugs Blocking SARS-CoV-2 Infection using Human Pluripotent Stem Cell-derived Colonic Organoids

Summary ParagraphThe current COVID-19 pandemic is caused by SARS-coronavirus 2 (SARS-CoV-2). There are currently no therapeutic options for mitigating this disease due to lack of a vaccine and limited knowledge of SARS-CoV-2 biology. As a result, there is an urgent need to create new disease models to study SARS-CoV-2 biology and to screen for therapeutics using human disease-relevant tissues. COVID-19 patients typically present with respiratory symptoms including cough, dyspnea, and respiratory distress, but nearly 25% of patients have gastrointestinal indications including anorexia, diarrhea, vomiting, and abdominal pain. Moreover, these symptoms are associated with worse COVID-19 outcomes1. Here, we report using human pluripotent stem cell-derived colonic organoids (hPSC-COs) to explore the permissiveness of colonic cell types to SARS-CoV-2 infection. Single cell RNA-seq and immunostaining showed that the putative viral entry receptor ACE2 is expressed in multiple hESC-derived colonic cell types, but highly enriched in enterocytes. Multiple cell types in the COs can be infected by a SARS-CoV-2 pseudo-entry virus, which was further validated in vivo using a humanized mouse model. We used hPSC-derived COs in a high throughput platform to screen 1280 FDA-approved drugs against viral infection. Mycophenolic acid and quinacrine dihydrochloride were found to block the infection of SARS-CoV-2 pseudo-entry virus in COs both in vitro and in vivo, and confirmed to block infection of SARS-CoV-2 virus. This study established both in vitro and in vivo organoid models to investigate infection of SARS-CoV-2 disease-relevant human colonic cell types and identified drugs that blocks SARS-CoV-2 infection, suitable for rapid clinical testing.

microbiology↗