Biology subjects

Sibilia, M.

Publications and source records attributed to Sibilia, M..

5 recordsLinked to original sources

bioRxiv2026

JAK1/2 Inhibition Restores Tissue Integrity by Rewiring Type 1/2 Immunity Toward Targetable IL-17 Responses

Effective immune responses require coordinated communication between immune and epithelial cells to eliminate pathogens while limiting tissue damage. Disruption of this balance drives chronic inflammation and progressive tissue destruction. The Janus kinase (JAK) pathway coordinates cytokine signaling across these compartments and has emerged as a therapeutic target in inflammatory diseases. However, the consequences of JAK inhibition within a complex inflammatory environment remain incompletely understood. Here, we dissect the molecular, cellular, immunological and phenotypical effects of topical JAK1/2 inhibition in a chronic model of tissue-destructive skin inflammation driven by barrier dysfunction and bacterial superinfection. Single-cell transcriptomics and functional profiling revealed that JAK1/2 blockade selectively suppressed pathogenic CD8 T cells and their IFN-{gamma} production while shifting Th2-polarized CD4 T cells toward a Th17 phenotype, preserving type 3 immunity consisting of IL-17A-producing {gamma}{delta}-T cells and neutrophil responses. This immune rebalancing occurs rapidly and concomitantly with the restoration of epithelial barrier integrity through tight junction reinforcement, followed by recovery of antimicrobial defenses and reduced bacterial burden. Combination of JAK1/2 and IL-17A blockade further improved tissue homeostasis by targeting residual type 3-driven pathology. Thus, JAK1/2 inhibition acts as selective immunomodulator rather than a broad immunosuppressant, targeting pathogenic type 1/2 responses while preserving type-3-associated antimicrobial defense programs. These findings reveal how JAK1/2 inhibition coordinates immune rebalancing with epithelial repair and support its therapeutic potential in chronic type 1/2-driven inflammatory disease, while identifying residual IL-17A-mediated pathology as a target for combination therapy.

immunology↗

bioRxiv2023

Scarring hair follicle destruction is driven by the collapse of EGFR-protected JAK-STAT1-sensitive stem cell immune privilege

The hair follicle stem cell niche is an immune-privileged microenvironment, characterised by suppressed antigen presentation, thus shielding against permanent immune-mediated tissue damage. In this study, we demonstrate the protective role of hair follicle-specific epidermal growth factor receptor (EGFR) from scarring hair follicle degeneration. Mechanistically, disruption of EGFR signalling generates a cell intrinsic hypersensitivity within the JAK-STAT1 pathway, compromising the immune privilege in the context of CD8 T cell and NK cell-mediated inflammation. Genetic depletion of either JAK1/2 or STAT1 or topical therapeutic inhibition of JAK1/2 restores the immune privilege and activates stem cells to resume hair growth in mouse models of epidermal and hair follicle specific EGFR deletion. Skin biopsies from EGFR inhibitor-treated and from EGFR-independent cicatricial alopecia patients indicate active STAT1 signalling within the hair follicles. Notably, a case study of folliculitis decalvans, characterised by progressive hair loss, scaling and perifollicular erythema, demonstrates successful treatment with systemic JAK1/2 inhibition. Our findings offer mechanistic insights and present a therapeutic strategy for addressing scarring hair follicle destruction associated with EGFR-inhibitor therapy and cicatricial alopecia.

immunology↗

bioRxiv2022

Resident T cells orchestrate adipose tissue remodeling in a site peripheral to infection

Infection with helminth parasites can affect adiposity, but underlying mechanisms that regulate this process are unclear. We found that fat content of mesenteric adipose tissue (mAT) declined in mice during infection with gut-restricted parasitic worms. This was associated with the accumulation of metabolically activated, immunostimulatory cytokine- and extracellular matrix-secreting multipotent stromal cells, which had potential to differentiate into preadipocytes. Concomitantly, mAT became infiltrated with Th2 lymphocytes that took up long-term residence and responded to signals from stromal cells by producing stromal cell-stimulating cytokines, including Amphiregulin. Signals delivered by Amphiregulin to stromal cells were required for immunity to infection. Our findings reveal intricate intercellular communication between Th2 cells and adipocyte progenitors and link immunity to intestinal infection to T cell-dependent effects on the adipocyte lineage.

immunology↗

bioRxiv2020

Cortical actin properties controlled by Drosophila Fos aid macrophage infiltration against surrounding tissue resistance

The infiltration of immune cells into tissues underlies the establishment of tissue resident macrophages, and responses to infections and tumors. Yet the mechanisms immune cells utilize to negotiate tissue barriers in living organisms are not well understood, and a role for cortical actin has not been examined. Here we find that the tissue invasion of Drosophila macrophages, also known as plasmatocytes or hemocytes, utilizes enhanced cortical F-actin levels stimulated by the Drosophila member of the fos proto oncogene transcription factor family (Dfos, Kayak). RNA sequencing analysis and live imaging show that Dfos enhances F-actin levels around the entire macrophage surface by increasing mRNA levels of the membrane spanning molecular scaffold tetraspanin TM4SF, and the actin cross-linking filamin Cheerio which are themselves required for invasion. Both the filamin and the tetraspanin enhance the cortical activity of Rho1 and the formin Diaphanous and thus the assembly of cortical actin, which is a critical function since expressing a dominant active form of Diaphanous can rescue the Dfos macrophage invasion defect. In vivo imaging shows that Dfos enhances the efficiency of the initial phases of macrophage tissue entry. Genetic evidence argues that this Dfos-induced program in macrophages counteracts the constraint produced by the tension of surrounding tissues and buffers the properties of the macrophage nucleus from affecting tissue entry. We thus identify strengthening the cortical actin cytoskeleton through Dfos as a key process allowing efficient forward movement of an immune cell into surrounding tissues.

cell biology↗

bioRxiv2019

Epidermal activation of Hedgehog signaling establishes an immunosuppressive microenvironment in basal cell carcinoma by modulating skin immunity

Genetic activation of Hedgehog (HH)/GLI signaling causes basal cell carcinoma (BCC), a very frequent non-melanoma skin cancer. Small molecule targeting of the essential HH effector Smoothened (SMO) proved an efficient medical therapy of BCC, although lack of durable responses and frequent development of drug resistance pose major challenges to anti-HH treatments. In light of the recent breakthroughs in cancer immunotherapy, we analyzed in detail the possible immunosuppressive mechanisms in HH/GLI-induced BCC. Using a genetic mouse model of BCC, we identified profound differences in the infiltration of BCC lesions with cells of the adaptive and innate immune system. Epidermal activation of HH/GLI led to an accumulation of immunosuppressive regulatory T cells, and to an increased expression of immune checkpoint molecules including PD-1/PD-L1. Anti-PD1 monotherapy, however, did not reduce tumor growth, presumably due to the lack of immunogenic mutations in common BCC mouse models, as shown by whole-exome sequencing. BCC lesions also displayed a marked infiltration with neutrophils, the depletion of which unexpectedly promoted BCC growth. The results provide a comprehensive survey of the immune status of murine BCC and provide a basis for the design of efficacious rational combination treatments. This study also underlines the need for predictive immunogenic mouse models of BCC to evaluate in vivo the efficacy of immunotherapeutic strategies.

cancer biology↗