Biology subjects

Valenzuela-Perez, L.

Publications and source records attributed to Valenzuela-Perez, L..

4 recordsLinked to original sources

bioRxiv2025

CD4+ T cells promote fibrosis during metabolic dysfunction-associated steatohepatitis

Unresolved inflammation and fibrosis are the two key features of metabolic dysfunction-associated steatohepatitis (MASH), a progressive form of steatotic liver disease that can evolve into cirrhosis and liver cancer. Although innate immunity has been well studied in MASH, the role of CD4 T cells remains underexplored despite their potential to coordinate immune responses by providing help to other immune cells, promoting inflammation, or regulating immune activity through effector and regulatory subsets. To better understand the role of CD4+ T cells in the pathogenesis of MASH, we comprehensively characterized hepatic CD4+ T cells in murine and human MASH at a single-cell protein, transcriptional, and functional level. Mass cytometry and CITE-sequencing revealed a marked shift in intrahepatic CD4 T-cell composition in MASH, with enrichment of Th1, regulatory, and cytotoxic CD4 T cells. Similar phenotypic changes were mirrored in the peripheral blood and validated in human MASH samples. Functional assays demonstrated increased production of IFN{gamma} and TNF by hepatic CD4 T cells, highlighting their proinflammatory effector activity. Transcriptomic profiling identified Tnfrsf4 (OX40) upregulation in hepatic CD4 T cells during MASH. Therapeutic blockade of the OX40L-OX40 axis reversed hepatic fibrosis and improved histologic disease scores in mice with established MASH, and also decreased inflammatory markers in a human ex vivo liver model. Together, these studies provide a proteogenomic single-cell atlas for hepatic CD4 T cells and uncover a CD4 T cell-dependent immunopathogenic circuit as a promising immunotherapeutic target to alleviate MASH and liver fibrosis.

immunology↗

bioRxiv2025

Metabolic Reprogramming of Pathogenic CD4+ T Helper Cells Attenuates Inflammatory Bowel Disease Pathogenesis

BACKGROUND & AIMSCD4+ T helper 1 (Th1) cells are involved in human inflammatory bowel disease (IBD) pathogenesis; however, mechanisms governing the persistent inflammatory function of these cells are unclear, leading us to examine how metabolism governs Th1 cell-induced IBD. METHODSTh1 cells supplemented with methyl pyruvate (MePyr) were analyzed to define how enforced mitochondrial pyruvate metabolism and subsequent glycogen synthase kinase 3{beta} (GSK3{beta}) deactivation reprogram cellular state. Re-analysis of the inflamed ileal single-cell RNA sequencing dataset from Crohns disease patients was performed to assess non-Treg CD4+ T cell metabolic gene signature. We assessed the capacity of a repurposed GSK3{beta} inhibitor to restrain pathogenic CD4+ T cell-driven murine colitis. RESULTSEffector Th1 cells exhibit a distinct metabolic program exemplified by glucose-driven glycolysis but low mitochondrial respiration. MePyr deactivates GSK3{beta}, glycolysis, and histone H3 acetylation on cytokine promoter region, resulting in reduced interferon-{gamma} (IFN-{gamma}) and tumor necrosis factor- (TNF-) expression in Th1 cells with concomitant gain of regulatory T cell-like program. GSK3{beta} inhibition with LY2090314 mirrored the anti-inflammatory effect of MePyr in a manner reversible by acetate supplementation, implying that GSK3{beta} potentially sustains glycolysis-derived acetyl-coenzyme A needed for histone acetylation and Th1 cell inflammatory response. Interleukin-21 exacerbates Th1 cell inflammatory response by maintaining a GSK3{beta}-driven glycolytic program. The Th1 cell metabolic gene signature downregulated by MePyr or GSK3{beta} inhibition in vitro is enriched in refractory Crohns disease patients. GSK3{beta} inhibition with LY2090314 retrains T cell-induced colitis in mice. CONCLUSIONSMePyr impairs GSK3{beta}-mediated glycolysis and Th1 cell immune response. GSK3{beta} inhibition may mitigate Th1 cell-induced human IBD. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=85 SRC="FIGDIR/small/649047v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@5b4acdorg.highwire.dtl.DTLVardef@18c03fforg.highwire.dtl.DTLVardef@15a75cforg.highwire.dtl.DTLVardef@1eca84d_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2023

Temperature influences the excretion time and parasitic load of Trypanosoma cruzi in the Triatoma infestans vector

Trypanosoma cruzi is a protozoan parasite transmitted by triatomine insect vectors, which expel their infectious dejections when they feed, causing Chagas disease in humans. The transmission and incidence of this vector-borne disease depend on the vital traits of its vectors, including Triatoma infestans, the main vector in Southern South America. Being an ectothermic species, its metabolism and its vital traits respond to temperature fluctuations. Here, we evaluated if changes in the average and variability of temperature expected with climate change modify: (i) the extrinsic incubation period (EIP) of T. cruzi within the vector T. infestans, (ii) its parasitic load, and (iii) the probability that its dejections were T. cruzi-positive. We acclimated triatomines infected with Dm28c T. cruzi strain to two constant and two variable temperature treatments and measured T. cruzi in their dejections by qPCR over a 42-day period. We observed that individuals in warm-temperature treatments showed lower EIP and higher parasitic load than cold-temperature treatments. Also, temperature variability can increase the parasitic load peak in cold-temperature treatments. Consequently, in a climate change scenario, there might be an increase in the vector capacity of T. infestans and probably a change in the risk of vectorial transmission of T. cruzi.

ecology↗

bioRxiv2023

Interleukin-21 Drives a Hypermetabolic State and CD4+ T Cell-associated Pathogenicity in Chronic Intestinal Inflammation

BACKGROUND & AIMSIncapacitated regulatory T cells (Tregs) contribute to immune-mediated diseases. Inflammatory Tregs are evident during human inflammatory bowel disease (IBD); however, mechanisms driving the development of these cells and their function are not well understood. Therefore, we investigated the role of cellular metabolism in Tregs relevant to gut homeostasis. METHODSUsing human Tregs, we performed mitochondrial ultrastructural studies via electron microscopy and confocal imaging, biochemical and protein analyses using proximity ligation assay, immunoblotting, mass cytometry and fluorescence-activated cell sorting, metabolomics, gene expression analysis, and real-time metabolic profiling utilizing Seahorse XF analyzer. We utilized Crohns disease single-cell RNA sequencing dataset to infer therapeutic relevance of targeting metabolic pathways in inflammatory Tregs. We examined the superior functionality of genetically-modified Tregs in CD4+ T cell-induced murine colitis models. RESULTSMitochondria-endoplasmic reticulum (ER) appositions, known to mediate pyruvate entry into mitochondria via VDAC1, are abundant in Tregs. VDAC1 inhibition perturbed pyruvate metabolism, eliciting sensitization to other inflammatory signals reversible by membrane-permeable methyl pyruvate (MePyr) supplementation. Notably, IL-21 diminished mitochondria-ER appositions, resulting in enhanced enzymatic function of glycogen synthase kinase 3 {beta} (GSK3{beta}), a putative negative regulator of VDAC1, and a hypermetabolic state that amplified Treg inflammatory response. MePyr and GSK3{beta} pharmacologic inhibitor (LY2090314) reversed IL-21-induced metabolic rewiring and inflammatory state. Moreover, IL-21-induced metabolic genes in Tregs in vitro were enriched in human Crohns disease intestinal Tregs. Adoptively transferred Il21r-/- Tregs efficiently rescued murine colitis in contrast to wild-type Tregs. CONCLUSIONSIL-21 triggers metabolic dysfunction associated with Treg inflammatory response. Inhibiting IL-21-induced metabolism in Tregs may mitigate CD4+ T cell-driven chronic intestinal inflammation.

immunology↗