Biology subjects

Dominguez-Villar, M.

Publications and source records attributed to Dominguez-Villar, M..

6 recordsLinked to original sources

bioRxiv2025

Accelerated memory T cell decline and tolerogenic recall responses to SARS-CoV-2 vaccination in diabetes

Type 1 and type 2 diabetes are associated with increased severity and mortality from respiratory virus infections, including SARS-CoV-2. Vaccination in the general population significantly reduces the risk of severe respiratory viral infection and triggers a strong, polyfunctional and lasting T cell response in healthy individuals. However, vaccine effectiveness in people with diabetes is unclear. Here we studied the magnitude and functional characteristics of vaccine-specific CD4+ and CD8+ T cell responses to the full vaccination protocol, and the recall response after a third booster dose of SARS-CoV-2 vaccine in people with type 1 and type 2 diabetes, and compared them to those of people without diabetes. We found defects in both CD4+ and CD8+ T cell memory maintenance and the functionality of the vaccine specific T cells in people with diabetes compared to people without. In those individuals with diabetes that harbored detectable vaccine-specific T cells, they displayed an unfocused, tolerogenic phenotype characterized by increased expression of IL-13 and IL-10 in T1D and T2D compared to people without diabetes. These results have implications for vaccination strategies for people with diabetes.

immunology↗

bioRxiv2024

Sphingosine-1-phosphate signaling inhibition suppresses Th1-like Treg generation by reversing mitochondrial uncoupling

Inflammatory environments induce the generation of dysfunctional IFN{gamma}+T-bet+FOXP3+ Th1-like Tregs, which show defective function and are found in autoimmune conditions including multiple sclerosis (MS). The pathways that control the generation of Th1-like Tregs are not well understood. Sphingosine-1-phosphate (S1P) signaling molecules are upregulated in Th1-like Tregs, and in vivo S1P inhibition with Fingolimod (FTY720) inhibits the expression of genes responsible for Treg plasticity in MS patients. However, the underlying mechanisms are unknown. Here we show that S1P signaling inhibition by FTY720 inhibits the generation of Th1-like Tregs and rescues their suppressive function. These effects are mediated by a decrease in mTORC1 signaling and reversal of the mitochondrial uncoupling that Tregs undergo during their reprogramming into Th1-like Tregs in vitro. Finally, these results are validated in in vivo generated Th1-like Tregs, as the Tregs from MS patients treated with FTY720 display decreased Th1-like Treg frequency, increased suppressive function, and mitochondrial metabolism rebalance. These results highlight the involvement of mitochondrial uncoupling in Treg reprogramming and identify S1P signaling inhibition as a target to suppress the generation of dysfunctional Th1-like Tregs.

immunology↗

bioRxiv2022

Jagged1 overexpression on T cells induces thymic regulatory T cells leading to thymic involution

We previously described a mouse model, tg66, with a severe defect resulting in diminished thymic size and complete involution by early adulthood. In the current study, we identified overexpression of Jagged1 as a mechanism for the alterations in thymic development in tg66 mice. T cells in the tg66 thymus were skewed towards CD8+ T cells, and within the CD4+ T cell compartment there was an over-representation of Foxp3+ cells. Regulatory Foxp3+ T cells (Tregs) isolated from tg66 mice had increased ST2 and CD103 expression. These Tregs could suppress proliferation to the same extent as conventional Tregs. Corroborating these results, tg66 mice were resistant to experimental induction of neuroinflammation in a common animal model for multiple sclerosis (EAE). Using bone marrow chimeras, we recorded a stark reduction in the number of thymocytes and a corresponding increase in Tregs in the thymus of mice receiving tg66 bone marrow. Conversely, through blocking Jagged1, the number of thymocytes was significantly increased, being concomitantly associated with a drop in the frequency of Tregs. We conclude that Tregs may play a role in thymic involution and could explain early thymic involution or loss as it is observed in diseases of thymic atrophy such as Down syndrome.

immunology↗

bioRxiv2022

Transcriptional reprogramming from innate immune functions to a pro-thrombotic signature upon SARS-CoV-2 sensing by monocytes in COVID-19

Alterations in the myeloid immune compartment have been observed in COVID-19, but the specific mechanisms underlying these impairments are not completely understood. Here we examined the functionality of classical CD14+ monocytes as a main myeloid cell component in well-defined cohorts of patients with mild and moderate COVID-19 during the acute phase of infection and compared them to that of healthy individuals. We found that ex vivo isolated CD14+ monocytes from mild and moderate COVID-19 patients display specific patterns of costimulatory and inhibitory receptors that clearly distinguish them from healthy monocytes, as well as altered expression of histone marks and a dysfunctional metabolic profile. Decreased NF{kappa}B activation in COVID-19 monocytes ex vivo is accompanied by an intact type I IFN antiviral response. Subsequent pathogen sensing ex vivo led to a state of functional unresponsiveness characterized by a defect in pro-inflammatory cytokine expression, NF{kappa}B-driven cytokine responses and defective type I IFN response in moderate COVID-19 monocytes. Transcriptionally, COVID-19 monocytes switched their gene expression signature from canonical innate immune functions to a pro-thrombotic phenotype characterized by increased expression of pathways involved in hemostasis and immunothrombosis. In response to SARS-CoV-2 or other viral or bacterial components, monocytes displayed defects in the epigenetic remodelling and metabolic reprogramming that usually occurs upon pathogen sensing in innate immune cells. These results provide a potential mechanism by which innate immune dysfunction in COVID-19 may contribute to disease pathology.

immunology↗

bioRxiv2020

Oleic acid Induces Tissue Resident FoxP3 Regulatory T cell Lineage Stability and Suppressive Functions

FoxP3 positive regulatory T cells (Tregs) rely on fatty acid {beta}-oxidation (FAO)-driven OXPHOS for differentiation and function. Recent data have demonstrated a role for Tregs in the maintenance of tissue homeostasis with tissue-resident Tregs possessing tissue-specific transcriptomes. However, specific signals that establish these tissue-resident Tregs programs are largely unknown. As Tregs metabolically rely on FAO, and considering the lipid-rich environments of tissues, we hypothesized that environmental lipids drive Treg homeostasis. Using human adipose tissue as a model for tissue residency, we identify oleic acid as the most prevalent free fatty acid in human adipose tissue. Mechanistically, oleic acid amplifies Treg FAO-driven OXPHOS metabolism, creating a positive feedback mechanism that induces the expression of Foxp3 and enhances phosphorylation of STAT5, which acts to stabilize the Treg lineage and increase suppressive function. Comparing the transcriptomic program induced by oleic acid to that of the pro-inflammatory arachidonic acid, we find that Tregs sorted from peripheral blood and adipose of healthy donors transcriptomically resemble the oleic acid in vitro treated Tregs, whereas Tregs obtained from the adipose tissue of relapsing-remitting MS patients more closely resemble an arachidonic acid profile. Finally, we find that oleic acid concentrations are reduced in the fat tissue of MS patients, and exposure of dysfunctional MS Tregs to oleic acid restores defects in their suppressive function. These data demonstrate the importance of fatty acids in regulating tissue inflammatory signals.

immunology↗

bioRxiv2018

PTGER2-β-Catenin Axis Links High Salt Environments to Autoimmunity by Balancing IFNγ and IL-10 in FoxP3+ Regulatory T cells

Foxp3+ regulatory T cells (Tregs) are the central component of peripheral immune tolerance. While dysregulation of the Treg cytokine signature has been observed in autoimmune diseases such as multiple sclerosis (MS) and type 1 diabetes, the regulatory mechanisms balancing pro- and anti-inflammatory cytokine production are not known. Here, we identify imbalance between IFN{gamma} and IL-10 as a shared Treg signature, present in patients with MS and under high salt conditions. By performing RNA-seq analysis on human Treg subpopulations, we identify {beta}-catenin as a key regulator that controls the expression of IFN{gamma} and IL-10. The activated {beta}-catenin signature is enriched specifically in IFN{gamma}+Tregs in humans, and this was confirmed in vivo with Treg-specific {beta}-catenin-stabilized mice exhibiting lethal autoimmunity with a dysfunctional, IFN{gamma}-producing, Treg phenotype. Moreover, we identify PTGER2 as a major factor balancing IFN{gamma} and IL-10 production in the context of a high salt environment, with skewed activation of the {beta}-catenin/SGK1/Foxo axis in IFN{gamma}+Tregs. These findings identify a novel molecular mechanism underlying inflammatory Tregs in human autoimmune disease and reveal a new role for a PTGER2-{beta}-catenin loop in Tregs linking environmental high salt conditions to autoimmunity.

immunology↗