Biology subjects

Prados, A.

Publications and source records attributed to Prados, A..

4 recordsLinked to original sources

bioRxiv2023

Cellular complexity and crosstalk in murine TNF-dependent ileitis: Different fibroblast subsets propel spatially defined ileal inflammation through TNFR1 signalling

Crohns disease represents a persistent inflammatory disorder primarily affecting the terminal ileum. Through the application of single-cell RNA sequencing, we unveil the intricate cellular complexities within murine TNF-dependent ileitis, developing in Tnf{Delta}ARE mice. Detailed immune cell analysis highlights B cell expansion, T cell effector reprogramming, and macrophage lineage shifts during inflammation. Focusing on stromal cells, we reveal a strong pro-inflammatory character, acquired by all fibroblast subsets, which exhibit complex communication patterns with the infiltrating immune and surrounding stromal cells. Interestingly, we identify that Tnf{Delta}ARE-induced ileitis is initiated in the lamina propria via TNFR1 pathway activation in villus-associated fibroblasts (Telocytes and Pdgfralow cells). Furthermore, we unveil separate spatial subsets of fibroblasts acting as exclusive responders to TNF, each orchestrating inflammation in different intestinal layers. Additionally, manipulating the Tnfrsf1a gene exclusively in fibroblast subsets suggests that inflammation is initiated by telocytes and Pdgfralow cells, while trophocytes drive its progression. This introduces novel evidence of spatial regulation of inflammation by fibroblast subsets, inciting and advancing disease in different layers of the gut. These findings underscore the pivotal role of fibroblasts in the inception and advancement of ileitis, proposing that targeting different fibroblast populations could impede the disease development and chronicity of inflammation.

cell biology↗

bioRxiv2022

miR-221/222 drive synovial fibroblast expansion and pathogenesis of TNF-mediated arthritis

MicroRNAs (miRNAs) constitute fine tuners of gene expression and are implicated in a variety of diseases spanning from inflammation to cancer. miRNA expression is deregulated in rheumatoid arthritis (RA), however, their specific role in key arthritogenic cells such as the synovial fibroblast (SF) remains elusive. We have shown in the past that the expression of the miR-221/222 cluster is upregulated in RA SFs. Here, we demonstrate that miR-221/222 activation is downstream of major inflammatory cytokines, such as TNF and IL-1{beta}, which promote miR-221/222 expression independently. miR-221/222 expression in SFs from the huTNFtg mouse model of arthritis correlates with disease progression. Targeted transgenic overexpression of miR-221/222 in SFs of the huTNFtg mouse model led to further expansion of synovial fibroblasts and disease exacerbation. miR-221/222 overexpression altered the transcriptional profile of SFs igniting pathways involved in cell cycle progression and ECM regulation. Validated targets of miR-221/222 included p27 and p57 cell cycle inhibitors, as well as Smarca1 (a chromatin remodeling component). In contrast, complete genetic ablation of miR-221/222 in arthritic mice led to decreased proliferation of fibroblasts, reduced synovial expansion and attenuated disease. scATAC-seq data analysis revealed increased miR-221/222 gene activity in the pathogenic and activated clusters of the intermediate and lining compartment. Taken together, our results establish an SF-specific pathogenic role of the miR-221/222 cluster in arthritis and suggest that its therapeutic targeting in specific subpopulations should inform the design of novel fibroblast-targeted therapies for human disease.

cell biology↗

bioRxiv2021

Col6a1+/CD201+ telocytes regulate intestinal morphogenesis and homeostasis

Intestinal mesenchymal cells encompass multiple subsets, whose origins, functions, and pathophysiological importance are still not clear. Here, we used the Col6a1Cre mouse, which targets telocytes and perivascular cells that can be further distinguished by the combination of the CD201, PDGFR and SMA markers. Developmental studies revealed that the Col6a1Cre mouse also targets mesenchymal aggregates that are crucial for intestinal morphogenesis and patterning, suggesting an ontogenic relationship between them and homeostatic telocytes. Cell depletion experiments in adulthood showed that Col6a1+/CD201+ mesenchymal cells regulate homeostatic enteroendocrine cell differentiation and epithelial proliferation. During acute colitis, they expressed an inflammatory and extracellular matrix remodeling gene signature, but they also retained their properties and topology. Notably, both in homeostasis and tissue regeneration, they were dispensable for normal organ architecture, while CD34+ mesenchymal cells expanded, localised at the top of the crypts and showed increased expression of villous-associated morphogenetic factors, providing thus evidence for the plasticity potential of distinct mesenchymal populations in the intestine. Our results provide a comprehensive analysis of the identities, origin, and functional significance of distinct mesenchymal populations in the intestine.

cell biology↗

bioRxiv2020

Antigen-presenting fibroblasts sustain anti-tumour CD4+ T cells in situ via MHCIIp-TCR and C1q-C1qbp binding.

A key unknown of the functional space in tumor immunity is whether physiologically relevant cancer antigen presentation occurs solely in draining lymph nodes versus tumors. Professional antigen presenting cells, i.e. the dendritic cells, are scarce and immature within tumors, greatly outnumbered by MHCII expressing non-hematopoietic cells, such as antigen-presenting cancer-associated fibroblasts (apCAFs). We hypothesized that after their exit from tumor-draining lymph nodes T cells depend on a second wave of antigen presentation provided in situ by structural cells. We show that dense apCAF regions in human lung tumors define hot immunological spots with increased numbers of CD4 T cells. The transcriptomic profile of human lung apCAFs aligned to that of pancreatic apCAFs across mice and humans and were both enriched for alveolar type II genes, suggesting an epithelial origin. Mechanistically, human apCAFs directly activated the TCRs of adjacent effector CD4 T cells and at the same time produced high levels of c1q, which acted on surface c1qbp on T cells to rescue them from apoptosis. Fibroblast-specific deletion of MHCII in mice impaired local MHCII immunity and accelerated tumor growth, while inducing c1qbp overexpression in adoptively transferred T cells expanded their numbers within tumors and reduced tumour burden. Collectively, our work shows that tumor T cell immunity post lymph node exit requires peripheral antigen presentation by a subset of CAFs and proposes a new conceptual framework upon which effective cancer immunotherapies can be built.

immunology↗