Biology subjects

Salgado, C. L.

Publications and source records attributed to Salgado, C. L..

5 recordsLinked to original sources

bioRxiv2026

Cholera toxin remodels intestinal immunity and suppresses systemic metabolism

Cholera toxin (CTx) is a potent enterotoxin and widely used mucosal adjuvant, yet the acute host response to CTx itself, in the absence of a co-administered antigen, remains vague. In this study, we integrated physiological and metabolic phenotyping with intestinal transcriptomics, epithelial imaging, immune profiling, hepatic gene-expression analysis, and paired microbiome profiling to characterize the response to a single oral CTx exposure in mice. Within 24 h, CTx remodeled immune-cell composition in both epithelial and lamina propria compartments, with responses shaped by sex and genetic background. Recurrent changes included increased epithelial group 3 innate lymphoid cells, reduced lamina propria ROR{gamma}t+ regulatory T cells, and decreased epithelial ILC1/NK cells in males of both strains. CTx also increased villus DCLK1+ tuft cells and reduced MUC2 immunoreactivity. Jejunal transcriptomics revealed induction of inflammatory defense, glycolytic, autophagy, and lipid-utilization programs together with suppression of proliferative and mitochondrial programs, consistent with coordinated stress adaptation. These local changes were accompanied by rapid restructuring of the fecal microbial community and by systemic hypometabolism, despite markedly different hypothermic responses across strains. CTx also elicited a selective hepatic stress and metabolic program, including conserved suppression of Cyp7a1 across sexes and strains. Together, these findings show that CTx alone rapidly reorganizes the intestinal immune, epithelial, metabolic, and microbial environment while suppressing whole-body metabolism. This work provides an integrated framework for understanding the acute host response to CTx and for interpreting its widespread use as a mucosal adjuvant.

immunology↗

bioRxiv2025

Escherichia coli-induced gut IL-33 release inhibits lung type 2 allergic responses

BackgroundThe incidence of lung allergies is reduced in countries with higher prevalence of infection and environmental exposure to microbes. However, enteric bacterial infections do not always correlate with lower incidence of allergic disorders and how lung immunity to allergens can be regulated by gut exposure to pathogens and their toxins is not fully understood. ObjectiveWe used mouse models of enterotoxigenic Escherichia coli (ETEC) infection and lung allergy to examine how gut exposure to bacteria, or their related toxins, affects allergic lung inflammation. MethodsNaive C57BL/6 mice were infected with enterotoxigenic Escherichia coli (ETEC) or orally treated with the ETEC LT toxin, to mimic enteric bacterial infections. After two weeks, these mice were treated intranasally with Ovalbumin (OVA) and Papain or IL-33, followed by challenge with OVA, to induce allergic lung inflammation that was assessed using multiple readouts. ResultsGut exposure to ETEC significantly inhibited allergic lung inflammation in a LT-dependent manner, as demonstrated by reduced tissue inflammation, less accumulation of type 2 cytokines, and reduced lung numbers of type 2 immune cells such as type 2 innate lymphoid cells (ILC2) and eosinophils. The anti-allergic capacity of LT was associated with reduced ability of lung ILC2s to recognize IL-33. Counterintuitively, deletion of either IL-33 or ILC2s significantly reverted the LT protective effect, suggesting the LT-mediated protection may occur through gut release and local sensing of IL-33. ConclusionsExposure to ETEC protects hosts against allergic lung inflammation through a negative feedback loop regulated by gut IL-33 release and sensing, suggesting a possible new immunological mechanism for reduced lung allergy incidence observed in areas with enteric bacterial infections. Key Messages- Enteric exposure to enterotoxigenic E. coli (ETEC) bacteria or its toxin LT significantly protects hosts against lung type 2 allergic inflammation. - ETEC and LT downregulate the capacity of lung ILC2s to respond to allergen-induced IL-33. - Deletion of IL-33 or ILC2s significantly impairs the protective effect of ETEC and LT, suggesting the presence of a negative feedback loop driven by toxin-induced gut IL-33 release.

immunology↗

bioRxiv2025

Sensing of extracellular ATP via P2RX7 drives lung tumor growth through regulatory T cell suppressive function

Lung cancer is the leading cause of cancer-related deaths worldwide and, despite treatment advances, immune suppression remains an obstacle to effective therapy. Effector CD4+ T cells (CD4+ Teffs) are critical for antitumor immunity, but their function is often inhibited by regulatory T cells (Tregs), which accumulate in lung tumors and perform suppressive functions through multiple mechanisms. This suppression leads to tumor progression and poor patient outcomes. However, the mechanisms underlying Treg-mediated suppression are not fully understood. Here, we identify the extracellular ATP receptor P2RX7 as a key regulator of Treg function in lung tumors. Using a murine lung cancer model induced by Lewis lung carcinoma cells, we demonstrate that P2RX7 enhances the suppressive capacity of tumor-infiltrating Tregs, promoting tumor growth. In T cell-specific P2RX7-KO mice, reduced Treg infiltration was accompanied by increased CD4+ Teff accumulation and improved tumor control. Treg-specific P2RX7-KO mice exhibit reduced tumor growth, confirming a cell-intrinsic role of P2RX7 in Tregs. Suppression assays revealed that tumor-infiltrating WT Tregs have greater suppressive activity compared to P2RX7-KO Tregs, which failed to inhibit type 1 and Tfh-like responses. This was associated with increased tumor-specific IgG production by lung B cells in P2RX7-KO mice. We also observed that WT Tregs express higher levels of the immunosuppressive surface molecule CTLA-4 when compared to P2RX7-KO Tregs. In summary, we show that P2RX7 expression on Tregs is essential for their suppressive function in lung cancer, and targeting of P2RX7 may constitute a novel strategy to improve lung cancer treatment by alleviating Treg-mediated immune suppression.

immunology↗

bioRxiv2023

Pannexin-1 channels promote CD8+ T cell effector and memory responses through distinct intracellular pathways

Sensing of extracellular ATP (eATP) controls CD8+ T cell function. Their accumulation can occur through export by specialized molecules, such as the release channel Pannexin-1 (Panx1). Whether Panx1 controls CD8+ T cell immune responses in vivo, however, has not been previously addressed. Here, we report that T cell-specific Panx1 is needed for CD8+ T cell responses to viral infections and cancer. We found that CD8-specific Panx1 promotes both effector and memory CD8+ T cell responses. Panx1 favors initial effector CD8+ T cell activation through extracellular ATP (eATP) export and subsequent P2RX4 activation, which helps promote full effector differentiation through extracellular lactate accumulation and its subsequent recycling. In contrast, Panx1 promotes memory CD8+ T cell survival primarily through ATP export and subsequent P2RX7 engagement, leading to improved mitochondrial metabolism. In summary, Panx1-mediated eATP export regulates effector and memory CD8+ T cells through distinct purinergic receptors and different metabolic and signaling pathways.

immunology↗

bioRxiv2021

SARS-CoV-2 Infection Impacts Carbon Metabolism and Depends on Glutamine for Replication in Syrian Hamster Astrocytes

Coronaviruses belong to a well-known family of enveloped RNA viruses and are the causative agent of the common cold. Although the seasonal coronaviruses do not pose a threat to human life, three members of this family, i.e., SARS-CoV, MERS-CoV and recently, SARS-CoV2, may cause severe acute respiratory syndrome and lead to death. Unfortunately, COVID-19 has already caused more than 4.4 million deaths worldwide. Although much is better understood about the immunopathogenesis of the lung disease, important information about systemic disease is still missing, mainly concerning neurological parameters. In this context, we sought to evaluate immunometabolic changes using in vitro and in vivo models of hamsters infected with SARS-CoV-2. Here we show that, besides infecting hamsters astrocytes, SARS-CoV-2 induces changes in protein expression and metabolic pathways involved in carbon metabolism, glycolysis, mitochondrial respiration, and synaptic transmission. Interestingly, many of the differentially expressed proteins are concurrent with proteins that correlate with neurological diseases, such as Parkinsonss disease, multiple sclerosis, amyotrophic lateral sclerosis, and Huntingtons disease. Metabolic analysis by high resolution real-time respirometry evidenced hyperactivation of glycolysis and mitochondrial respiration. Further metabolomics analysis confirmed the consumption of many metabolites, including glucose, pyruvate, glutamine, and alpha ketoglutarate. Interestingly, we observed that glutamine was significantly reduced in infected cultures, and the blockade of mitochondrial glutaminolysis significantly reduced viral replication and pro-inflammatory response. SARS-CoV-2 was confirmed in vivo as hippocampus, cortex, and olfactory bulb of intranasally infected hamsters were positive for viral genome several days post-infection. Altogether, our data reveals important changes in overall protein expression, mostly of those related to carbon metabolism and energy generation, causing an imbalance in important metabolic molecules and neurotransmitters. This may suggest that some of the neurological features observed during COVID-19, as memory and cognitive impairment, may rely on altered energetic profile of brain cells, as well as an unbalanced glutamine/glutamate levels, whose importance for adequate brain function is unquestionable.

immunology↗