Biology subjects

Gudi, R. R.

Publications and source records attributed to Gudi, R. R..

10 recordsLinked to original sources

bioRxiv2026

Neutrophil Extracellular Trap Formation and Complement Activation Pathways Dominate Microbiota-dependent disease bias in lupus-prone female NZM2328 mice

Women are predisposed to systemic lupus erythematosus (SLE) with a prevalence ratio of up to 9:1 over men. Multiple mouse strains including NZM2328 exhibit strong female dominance in developing spontaneous lupus as in humans with SLE. While lupus-prone mice can develop disease under germ free (GF) condition, the role of gut microbiota in female bias for lupus nephritis is not investigated systematically. Here, using specific pathogen free (SPF) and GF NZM2328 mice, and employing microbiota-depletion and microbial-association strategies, we show that microbiota influences lupus-like disease outcomes differently in males and females. Female NZM2328 mice with intact microbiota presents higher inflammation factor expression, including X-chromosome linked TLRs, in the distal gut and systemic compartments, and higher activation of genes and biological pathways such as neutrophil extracellular trap (NET) formation and complement and coagulation cascade (CCC) pathways, associating with their higher disease susceptibility. Gut microbiota-depletion as well as GF derivation eliminated not only the modest differences in the serum and fecal antibody levels and nAg reactivity, but also the gender bias in the timing of clinical stage disease onset as well as systemic NET and CCC pathway activation. Reciprocally, conventionalization of GF NZM2328 mice at juvenile age restored the female bias in intestinal and systemic autoantibody levels, pro-inflammatory immune pathway activation, and the timing of clinical stage disease onset. Overall, our observations show that, while genetic susceptibility appears to be the cause of lupus-like disease in NZM2328 mice, differential activation of NET and CCC pathways in males and females upon exposure to gut microbes, in combination with host-factors, causes gender bias in disease outcomes. We conclude that microbiota exposure-dependent protection of males and overactivation of NET and CCC pathways in females could be contributing to the female bias in lupus-like disease in NZM2328 mice.

immunology↗

bioRxiv2026

CPAP/CENPJ is essential for the stability and function of AAA+ ATPase VPS4B

Function of CENPJ/CPAP is essential for centriole duplication and cilia biogenesis, disruption of which can lead to microcephaly and Seckel syndrome. Recently, we showed that CPAP is an integral Endosomal Sorting Complexes Required for Transport (ESCRT)-0-like protein that recruits ESCRT-I protein TSG101 to early endosome (EE) and it positively regulates multi-vesicular body (MVB) formation. Sequential recruitment of the ESCRT protein complexes and AAA+ ATPase VPS4B to EE facilitates MVB biogenesis. VPS4B is critical for ESCRT-III disassembly/recycling and contributes to membrane fission in several cellular processes. Here, we report that CPAP is critical for the protein stability and EE localization of VPS4B, and this function is independent from its role as an ESCRT-0 protein. Other well-recognized VPS4B-dependent cellular processes such as cytokinesis, extracellular vesicle production, and retroviral budding are also compromised under CPAP deficiency. We found that CPAP overexpression leads to cellular accumulation and CPAP deficiency causes proteasomal degradation of VPS4B. We also found that VPS4B interacts with the C-terminal CC4 domain of CPAP, which is considered as its centriole localization domain, and this interaction prevents the proteasome degradation of VPS4B. Notably, the EE localization of VPS4B can be attributed to microcephaly-associated C-terminal TCP domain of CPAP. Overall, these observations provide evidence that CPAP is critical for VPS4B and its ESCRT-associated function and suggest that distinct pools of CPAP may be involved in its ESCRT-0 and VPS4B stabilization roles. This study also provides clues to potential mechanisms underlying the clinical phenotypes of CPAP deficiency.

cell biology↗

bioRxiv2025

Centrosomal P4.1-associated protein (CPAP) is a novel regulator of ESCRT pathway function during multivesicular body formation and endosome maturation

Previously, we reported that Centrosomal P4.1-associated protein (CPAP/CENPJ/SAS-4) positively regulates multivesicular body (MVB) biogenesis and endocytic vesicular transport (EVT). Here, we show that CPAP is required for Rab5-to-Rab7 conversion, and recruitment of TSG101 to early endosome (EE) is the molecular mechanism by which CPAP promotes MVB formation. CPAP depletion disrupts Rab7 and TSG101 recruitment to EE and blocks endosome maturation. While endogenous CPAP co-precipitates with ESCRT-proteins TSG101, HRS and ALIX, exogenously expressed CPAP only interacts with TSG101. CPAP localizes to endosome and colocalizes with HRS and TSG101 during EVT progression. TSG101 recruitment to endosome, Rab5-to-Rab7 conversion, and EVT of EGFR to MVB in CPAP-depleted cells are restored by re-introduction of CPAP or overexpression of, but not endogenous, HRS. These observations show that CPAP is an ESCRT-associated protein, which functions upstream of TSG101, but in parallel to HRS, during MVB formation and EVT of cargo to the lysosome. HighlightsO_LICPAP-deficiency prevents Rab5-Rab7 conversion and TSG101 recruitment to early endosomes during MVB formation C_LIO_LICPAP is an essential ESCRT protein C_LIO_LICPAP functions parallel to HRS during MVB formation C_LIO_LICPAP-TSG101 interaction is essential for Rab5-Rab7 conversion and endosome maturation C_LI

cell biology↗

bioRxiv2025

Gut colonization by Bacteroides fragilis at juvenile age alters microbiota composition and accelerates type 1 diabetes progression in non-obese diabetic mice

Type 1 diabetes (T1D) in humans is associated with higher Bacteroidetes : Firmicutes ratio and higher abundance of Bacteroides genus members. Bacteroides fragilis (BF) is an integral component of the human colonic commensal microbiota. Here, we show that gut colonization of specific pathogen-free (SPF) non-obese diabetic (NOD) mice by BF at a juvenile age induces a pro-inflammatory immune response and accelerated disease progression. NOD mice born to BF-monocolonized parents not only showed rapid disease progression compared to germ-free (GF) controls but also preserved accelerated disease onset and higher disease incidence upon conventionalization, suggesting that BF contributes to a pro-inflammatory response and autoimmunity in T1D. Interestingly, we found that while gut microbiota composition was different in control and BF-colonized SPF mice, presence of BF alone could significantly impact the acquisition of microbial communities upon conventionalization of gnotobiotic mice. Bulk RNAseq analysis of colon tissues revealed profound differences in the gene expression pattern of GF and BF-monocolonized mice as well as their conventionalized counterparts, shedding light on the probable mechanisms contributing to accelerated disease onset in mice that are exposed to BF. We found that mucin production is downregulated and the abundance of mucin degraders such as Akkermansia muciniphila is profoundly lower in BF-colonized mice that are conventionalized. Overall, these studies demonstrate that early life acquisition of BF-like distal gut commensals could have profound modulatory effects on the eventual overall gut microbiota structure, immune function, and {beta}-cell specific autoimmune outcomes under genetic susceptibility.

immunology↗

bioRxiv2021

Activation of T cell checkpoint pathways during beta-cell antigen presentation by engineered dendritic cells promotes protection of non-obese diabetic mice from type 1 diabetes

Defective immune regulation has been recognized in type 1 diabetes (T1D). Immune regulatory T cell check-point receptors, which are generally upregulated on activated T cells, have been the molecules of attention as therapeutic targets for enhancing immune response in tumor therapy. We reported that dendritic cells (DCs) that are engineered to express selective ligands for checkpoint receptors can induce effective T cell tolerance in antigen-immunization models. Here, we show that pancreatic {beta} -cell antigen (BcAg) presentation by engineered tolerogenic-DCs (tDCs) that express CTLA4 selective ligand (B7.1wa) or a combination of CTLA4, PD1 and BTLA selective ligands (B7.1wa, PD-L1, and HVEM-CRD1 respectively; multiligand-DCs) causes an increase in regulatory cytokine and T cell (Treg) responses and suppression of the effector T cell function as compared to engineered control-DCs. Non-obese diabetic (NOD) mice treated with BcAg-pulsed CTLA4-ligand-DCs and multiligand-DCs at pre-diabetic and early-hyperglycmic stages showed significantly lower degree of insulitis, higher frequencies of insulin-positive islets, profound delay in, and reversal of, hyperglycemia for a significant duration. Immune cells from the tDC treated mice not only produced lower amounts of IFN{gamma} and higher amounts of IL10 and TGF{beta}1 upon BcAg challenge, but also failed to induce hyperglycemia upon adoptive transfer. While both CTLA4-ligand-DCs and multiligand-DCs were effective in inducing tolerance, multiligand-DC treatment produced an overall higher suppressive effect on effector T cell function and disease outcome. These studies show that enhanced engagement of T cell checkpoint receptors during BcAg presentation can modulate T cell function and suppress autoimmunity and progression of the disease in T1D.

immunology↗

bioRxiv2021

Gastrin producing syngeneic mesenchymal stem cells protect non-obese diabetic mice from type 1 diabetes

Progressive destruction of pancreatic islet {beta}-cells by immune cells is a primary feature of type 1 diabetes (T1D) and therapies that can restore the functional {beta}-cell mass are needed to alleviate disease progression. Here, we report the use of mesenchymal stromal/stem cells (MSCs) for the production and delivery of Gastrin, a peptide-hormone which is produced by intestinal cells and fetal islets and can increase {beta}-Cell mass, to promote protection from T1D. A single injection of syngeneic MSCs that were engineered to express Gastrin (Gastrin-MSCs) caused a significant delay in hyperglycemia in non-obese diabetic (NOD) mice compared to engineered control-MSCs. Similar treatment of early-hyperglycemic mice caused the restoration of euglycemia for a considerable duration, and these therapeutic effects were associated with protection of, and/or higher frequencies of, insulin producing islets and less severe insulitis. While the overall immune cell phenotype was not affected profoundly upon treatment using Gastrin-MSCs or upon in vitro culture, pancreatic lymph node cells from Gastrin-MSC treated mice, upon ex vivo challenge with self-antigen, showed a Th2 and Th17 bias, and diminished the diabetogenic property in NOD-Rag1 deficient mice suggesting a disease protective immune modulation under Gastrin-MSC treatment associated protection from hyperglycemia. Overall, this study shows the potential of production and delivery of Gastrin in vivo, by MSCs, in protecting insulin producing {beta}-cells and ameliorating the disease progression in T1D.

immunology↗

bioRxiv2019

Impacts of Gut Microbiota on Gender Bias in Intestinal Pro-Inflammatory Immune Phenotype and Systemic Autoimmune Progression in Lupus-prone SNF1 mice

1.The risk of developing systemic lupus erythematosus (SLE) is about 9 times higher among women compared to men. Our recent report, which used (SWRxNZB) F1 (SNF1) mouse model of spontaneous lupus, showed a potential link between immune response initiated in the gut mucosa at juvenile age (sex hormone independent) and SLE susceptibility. Here, this mouse model, we show that gut microbiota contributes to a pro-inflammatory immune response in the intestine and autoimmune progression, primarily in females, leading to an associated gender bias. We found that gut microbiota composition in male and female littermates are significantly different only at adult age and depletion of gut microbes causes suppression of autoimmune progression only in females. In agreement, microbiota depletion suppressed the pro-inflammatory cytokine response of gut mucosa in both juvenile and adult females. In male SNF1 mice, on the other hand, orchidectomy (castration) caused changes in the composition of gut microbiota and a modest acceleration of autoimmune progression. However, cecum microbiota transplantation studies failed to show superior protection of females from autoimmunity by androgen-influenced gut microbiota. Overall, our work shows that microbiota-dependent pro-inflammatory immune response in the gut mucosa of females initiated at juvenile ages and androgen-dependent protection of males contributes to gender differences in the intestinal immune phenotype and systemic autoimmune progression.

immunology↗

bioRxiv2019

Engineered Dendritic Cell-Directed Concurrent Activation of Multiple T cell Inhibitory Pathways Induces Robust Immune Tolerance

Inhibitory/repressor-receptors are upregulated significantly on activated T cells, and have been the molecules of attention as targets for inducing immune tolerance. Induction of effective antigen specific tolerance depends on concurrent engagement of the TCR and one or more of these inhibitory receptors. Here, we show, for the first time that dendritic cells (DCs) can be efficiently engineered to express multiple T cell inhibitory ligands, and enhanced engagement of T cell inhibitory receptors, upon antigen presentation, by these DCs can induce effective CD4+ T cell tolerance and suppress autoimmunity. Compared to control DCs, antigen presentation by DCs that ectopically express CTLA4, PD1 and BTLA selective ligands (B7.1wa, PD-L1, and HVEM-CRD1 respectively) individually (mono-ligand DCs) or in combination (multi-ligand DCs) causes an inhibition of CD4+ T cell proliferation and pro-inflammatory cytokine response, as well as increase in Foxp3+ Treg frequency and immune regulatory cytokine production. Administration of self-antigen (mouse thyroglobulin; mTg) loaded multi-ligand DCs caused hyporesponsiveness to mTg challenge, suppression of autoantibody production, and amelioration of experimental autoimmune thyroiditis. Overall, this study shows that engineered DC-directed enhanced concurrent activation of multiple T cell coinhibitory pathways is an effective way to induce self-antigen specific T cell tolerance to suppress ongoing autoimmunity.

immunology↗

bioRxiv2018

Polysaccharide A-dependent opposing effects of mucosal and systemic exposures to human gut commensal Bacteroides fragilis in type 1 diabetes

Bacteroides fragilis (BF) is an integral component of the human colonic commensal microbiota. BF is also the most commonly isolated organism from clinical cases of intra-abdominal abscesses suggesting its potential to induce pro-inflammatory responses, upon accessing the systemic compartment. Hence, we examined the impact of mucosal and systemic exposures to BF on type 1 diabetes (T1D) incidence in non-obese diabetic (NOD) mice. The impact of intestinal exposure to BF under chemically-induced enhanced gut permeability condition, which permits microbial translocation, in T1D was also examined. While oral administration of pre-diabetic mice with heat-killed (HK) BF caused enhanced immune regulation and suppression of autoimmunity resulting in delayed hyperglycemia, mice that received HK BF by i.v. injection showed rapid disease progression. Importantly, polysaccharide-A deficient ({Delta}PSA) BF failed to produce these opposing effects upon oral and systemic deliveries. Further, BF induced modulation of disease progression was observed in WT, but not TLR2-deficient, NOD mice. Interestingly, oral administration of BF under enhanced gut permeability condition resulted in accelerated disease progression and rapid onset of hyperglycemia in NOD mice. Overall, these observations suggest that BF-like gut commensals can cause pro-inflammatory responses upon gaining access to systemic compartment and contribute to T1D in at-risk subjects.

immunology↗

bioRxiv2018

Complex dietary-polysaccharide modulates gut immune function and microbiota, and promotes protection from autoimmune diabetes

Since the dietary supplement and prebiotic value of {beta}-glucan-rich products have been widely recognized and the dietary approaches for modulating autoimmunity have been increasingly explored, we assessed the impact of oral administration of high-pure yeast {beta}-glucan (YBG) on gut immune function, microbiota and type 1 diabetes (T1D) using mouse models. Oral administration of this non-digestible complex polysaccharide caused a Dectin-1-dependent immune response involving increased expression of IL10, retinaldehyde dehydrogenase (Raldh) and pro-inflammatory cytokines in the gut mucosa. YBG-exposed intestinal DCs induced/expanded primarily Foxp3+, IL10+ and IL17+ T cells, ex vivo. Importantly, prolonged oral administration of low-dose YBG at pre-diabetic stage suppressed insulitis and significantly delayed the T1D incidence in non-obese diabetic (NOD) mice. Further, prolonged treatment with YBG showed increased Foxp3+ T cell frequencies, and a significant change in the gut microbiota, particularly an increase in the abundance of Bacteroidetes and a decrease in the Firmicute members. Oral administration of YBG, together with Raldh-substrate and {beta}-cell antigen, resulted in a better protection of NOD mice from T1D. These observations suggest that YBG not only has a prebiotic property, but also has an oral tolerogenic-adjuvant-like effect, and these features could be exploited for modulating autoimmunity in T1D.

immunology↗