Biology subjects

Mas, V.

Publications and source records attributed to Mas, V..

4 recordsLinked to original sources

bioRxiv2025

Transplant immunosuppressant therapies induce unique functional changes in lymph node and re-shape gut immune homeostasis

BackgroundLifelong immunosuppressive therapy is required to prevent allograft rejection in organ transplantation. Current immunosuppressants effectively suppress adaptive and innate immune responses, but their broad, antigen-non-specific effects often result in severe off-target complications. It remains a significant unmet medical need in transplant medicine. ResultsIn this study we investigated immunosuppressant effects of four major immunosuppressant classes, including tacrolimus, prednisone, mycophenolate mofetil (MMF), and fingolimod (FTY), on the gut microbiome, metabolic pathways, lymphoid architecture and lymphocyte trafficking after up to 30-day chronic exposure. Despite their distinct mechanisms of action and not designed to target the gut, all immunosuppressive drugs induced profound and time-dependent alterations in both intestine gene expression and gut microbiome composition. Progressive alterations from moderate early, drug-specific changes to a strikingly convergent microbial dysbiosis, marked by significant expansion of pathobionts of Muribaculaceae, occurred across all drug classes. Concurrently, all drugs uniformly induced significant suppression of mucosal immunity including B cell, immunoglobulin, and antigen recognition. Time-dependent changes in lymph node (LN) reorganization and cellular composition were also observed, marked by a progressive shift toward pro-inflammatory phenotypes in gut-draining mesenteric LNs and a gradual loss of tolerogenic architecture in peripheral LNs. Drug-specific metabolic alterations and distinct phases of intestinal transcriptional responses were also characterized. Notably, MMF and FTY demonstrated the most robust immunomodulatory properties, and were able to suppress alloantigen-induced inflammation through mediating regulatory T cell distribution and LN remodeling. ConclusionsTogether, these findings highlight the underappreciated complexity and temporal dynamics immunosuppressants effects, particularly their impact on the gut and compartmentalized regulation of alloimmune in lymphoid tissues. Understanding these relationships offers new opportunities for refining immunosuppressive strategies to reduce treatment-related off-target complications and improve long-term organ transplant outcomes.

immunology↗

bioRxiv2024

Shroom3-Rock interaction and profibrotic function: Resolving mechanism of an intronic CKD risk allele.

Common intronic enhancer SNPs in Shroom3 associate with CKD in GWAS, although there is paucity of detailed mechanism. Previously, we reported a role for Shroom3 in mediating crosstalk between TGF{beta}1- & Wnt/Ctnnb1 pathways promoting renal fibrosis (TIF). However, beneficial roles for Shroom3 in proteinuria have also been reported suggesting pleiotropic effects. Here we focused on identifying the specific profibrotic Shroom3 motif. Given known therapeutic roles for Rho-kinase inhibitors in experimental CKD, and the established interaction between Shroom3 and Rock via its ASD2 domain, we hypothesized that Shroom3-mediated ROCK activation played a crucial role in its profibrotic function in high expressors. To test this hypothesis, we developed transgenic mice and cell lines that inducibly overexpressed wild-type- (WT-Sh3) or ASD2-domain deletion- Shroom3 (ASD2{Delta}-Sh3). Prior scRNAseq data showed that during TIF, Shroom3 and Rock co-expression occurred in injured tubular cells and fibroblasts, highlighting cell-types where this mechanism could be involved. Using HEK293T cells, we first confirmed absent ROCK binding and inhibited TGF{beta}1-signaling with ASD2{Delta}-Sh3-overexpression vs WT-Sh3. In mIMCD cells, ASD2{Delta}-Sh3 overexpression, reduced Rock activation (phospho-MYPT1), pro-fibrotic and pro-inflammatory transcripts vs WT-Sh3. Fibroblast proliferation (3T3) was also reduced with ASD2{Delta}-Sh3. In vivo, we studied ureteric obstruction (UUO) and Aristolochic nephropathy (AAN) as TIF models. In AAN, inducible global-, or Pan-tubular specific-, WTSh3-overexpression showed increased azotemia, and TIF vs ASD2{Delta}-Sh3 mice. WT-Sh3 mice consistently showed significant enrichment of Rho-GTPase, TGF{beta}1- and Wnt/CtnnB1- signaling in kidney transcriptome, paralleling Shroom3-coexpressed genes in tubulo-interstitial transcriptomes from human CKD. In UUO, again WT-Sh3 mice recapitulated increased fibrosis vs ASD2{Delta}-Sh3. Importantly, ASD2{Delta}-Sh3 did not develop albuminuria vs WT-Sh3, while mutating a disparate Fyn-binding Shroom3 motif induced albuminuria in mice, suggesting motif-specific roles for Shroom3 in the kidney. Hence, our data show a critical role for the Rock-binding, ASD2-domain in mediating TIF in milieu of Shroom3 excess, with relevance to human CKD.

systems biology↗

bioRxiv2024

Rapamycin Immunomodulation Utilizes Time-Dependent Alterations of Lymph Node Architecture, Leukocyte Trafficking, and Gut Microbiome

Transplant recipients require lifelong, multimodal immunosuppression to prevent rejection by reducing alloreactive immunity. Rapamycin, a mechanistic target of rapamycin (mTOR) inhibitor, is known to modulate adaptive and innate immunity, while the full spectrum of its immunosuppressive mechanisms remains incompletely understood. Given the broad expression of mTOR, we investigated the understudied effects of rapamycin on lymph node (LN) architecture, leukocyte trafficking, and the gut microbiome and metabolism after 3, 7, and 30 days of rapamycin treatment, to characterize the early, intermediate, and late changes. Rapamycin significantly reduced CD4+ T cells, CD8+ T cells, and regulatory T (Treg) cells in peripheral LNs, mesenteric LNs, and the spleen over time. Rapamycin induced early pro-inflammation transition to pro-tolerogenic status, by modulating the LN laminin 4:5 expression ratios through LN stromal cells laminin 5 expression and by adjusting Treg numbers and distribution. Additionally, rapamycin significantly altered gut microbiota composition and metabolic functions, shifting the Bacteroides to Firmicutes ratio and increasing amino acid bioavailability in the gut lumen. These effects were evident by 7 days and became most pronounced by 30 days in naive mice, with notable changes as early as 3 days in allogeneic splenocyte-stimulated mice. These findings reveal a novel mechanism of rapamycins action through time-dependent modulation of LN architecture and gut microbiome, which orchestrates changes in immune cell trafficking, providing a new framework for understanding and optimizing immunosuppressive therapies.

immunology↗

bioRxiv2019

Trivalent cocktail of de novo designed immunogens enables the robust induction and focusing of functional antibodies in vivo

De novo protein design has been successful in expanding the natural protein repertoire. However, most de novo proteins lack biological function, presenting a major methodological challenge. In vaccinology, the induction of precise antibody responses remains a cornerstone for next-generation vaccines. Here, we present a novel protein design algorithm, termed TopoBuilder, with which we engineered epitope-focused immunogens displaying complex structural motifs. Both in mice and non-human primates, cocktails of three de novo designed immunogens induced robust neutralizing responses against the respiratory syncytial virus. Furthermore, the immunogens refocused pre-existing antibody responses towards defined neutralization epitopes. Overall, our de novo design approach opens the possibility of targeting specific epitopes for vaccine and therapeutic antibody development, and more generally will be applicable to design de novo proteins displaying complex functional motifs.

bioengineering↗