Tregs In Skin Research Articles

Jagged-1+ skin Tregs modulate cutaneous wound healing

Skin-resident regulatory T cells (Tregs) play an irreplaceable role in orchestrating cutaneous immune homeostasis and repair, including the promotion of hair regeneration via the Notch signaling ligand Jagged-1 (Jag1). While skin Tregs are indispensable for facilitating tissue repair post-wounding, it remains unknown if Jag1-expressing skin Tregs impact wound healing. Using a tamoxifen inducible Foxp3creERT2Jag1fl/fl model, we show that loss of functional Jag1 in Tregs significantly delays the rate of full-thickness wound closure. Unlike in hair regeneration, skin Tregs do not utilize Jag1 to impact epithelial stem cells during wound healing. Instead, mice with Treg-specific Jag1 ablation exhibit a significant reduction in Ly6G + neutrophil accumulation at the wound site. However, during both homeostasis and wound healing, the loss of Jag1 in Tregs does not impact the overall abundance or activation profile of immune cell targets in the skin, such as CD4+ and CD8+ T cells, or pro-inflammatory macrophages. This collectively suggests that skin Tregs may utilize Jag1-Notch signalling to co-ordinate innate cell recruitment under conditions of injury but not homeostasis. Overall, our study demonstrates the importance of Jag1 expression in Tregs to facilitate adequate wound repair in the skin.

Intranasal Immunization of Pneumococcal pep27 Mutant Attenuates Allergic and Inflammatory Diseases by Upregulating Skin and Mucosal Tregs.

Conventional immunization methods such as intramuscular injections lack effective mucosal protection against pathogens that enter through the mucosal surfaces. Moreover, conventional therapy often leads to adverse events and compromised immunity, followed by complicated outcomes, leading to the need to switch to other options. Thus, a need to develop safe and effective treatment with long-term beneficial outcomes to reduce the risk of relapse is mandatory. Mucosal vaccines administered across mucosal surfaces, such as the respiratory or intestinal mucosa, to prompt robust localized and systemic immune responses to prevent the public from acquiring pathogenic diseases. Mucosal immunity contains a unique immune cell milieu that selectively identify pathogens and limits the transmission and progression of mucosal diseases, such as allergic dermatitis and inflammatory bowel disease (IBD). It also offers protection from localized infection at the site of entry, enables the clearance of pathogens on mucosal surfaces, and leads to the induction of long-term immunity with the ability to shape regulatory responses. Regulatory T (Treg) cells have been a promising strategy to suppress mucosal diseases. To find advances in mucosal treatment, we investigated the therapeutic effects of intranasal pep27 mutant immunization. Nasal immunization protects mucosal surfaces, but nasal antigen presentation appears to entail the need for an adjuvant to stimulate immunogenicity. Here, a novel method is developed to induce Tregs via intranasal immunization without an adjuvant to potentially overcome allergic diseases and gut and lung inflammation using lung-gut axis communication in animal models. The implementation of the pep27 mutant for these therapies should be preceded by studies on Treg resilience through clinical translational studies on dietary changes.

Interleukin-2-induced skin inflammation.

Recombinant human IL-2 has been used to treat inflammatory diseases and cancer; however, side effects like skin rashes limit the use of this therapeutic. To identify key molecules and cells inducing this side effect, we characterized IL-2-induced cutaneous immune reactions and investigated the relevance of CD25 (IL-2 receptor α) in the process. We injected IL-2 intradermally into WT mice and observed increases in immune cell subsets in the skin with preferential increases in frequencies of IL-4- and IL-13-producing group 2 innate lymphoid cells and IL-17-producing dermal γδ Tcells. This overall led to a shift toward type 2/type 17 immune responses. In addition, using a novel topical genetic deletion approach, we reduced CD25 on skin, specifically on all cutaneous cells, and found that IL-2-dependent effects were reduced, hinting that CD25 - at least partly - induces this skin inflammation. Reduction of CD25 specifically on skin Tregs further augmented IL-2-induced immune cell infiltration, hinting that CD25 on skin Tregs is crucial to restrain IL-2-induced inflammation. Overall, our data support that innate lymphoid immune cells are key cells inducing side effects during IL-2 therapy and underline the significance of CD25 in this process.

Regulatory T cells in skin mediate immune privilege of the hair follicle stem cell niche.

Immune tolerance is maintained in lymphoid organs (LOs). Despite the presence of complex immune cell networks in non-LOs, it is unknown whether self-tolerance is maintained in these tissues. We developed a technique to restrict genetic recombination to regulatory T cells (Tregs) only in skin. Selective depletion of skin Tregs resulted in T cell-mediated inflammation of hair follicles (HFs). Suppression did not rely on CTLA-4, but instead on high-affinity interleukin-2 (IL-2) receptor expression by skin Tregs, functioning exclusively in a cell-extrinsic manner. In a novel model of HF stem cell (HFSC)-driven autoimmunity, we reveal that skin Tregs immunologically protect the HFSC niche. Finally, we used spatial transcriptomics to identify aberrant IL-2 signaling at stromal-HF interfaces in a rare form of human alopecia characterized by HFSC destruction and alopecia areata. Collectively, these results reveal the fundamental biology of Tregs in skin uncoupled from the systemic pool and elucidate a mechanism of self-tolerance.

Harmine and Kaempferol treatment enhances NFATC1 and FOXP3 mediated regulatory T-cells’ suppressive capacity in generalized vitiligo

BackgroundGeneralized vitiligo (GV) is an autoimmune disease characterized by the progressive loss of melanocytes. ObjectivesCurrent study was undertaken to assess in-vitro therapeutic potential of Harmine and Kaempferol for GV. MethodsCalcium, calcineurin, NFATC1 levels, cell proliferation were assessed by various kits and ORAI1, PEIZO1, Calcineurin, GSK3B, DYRK1A transcripts and IFN-γ,IL-10,TGF-β protein levels were assessed by qPCR and ELISA in blood and skin biopsy samples from Tregs of 52 patients and 50 controls. ResultsHarmine and Kaempferol treatment enhances Treg suppressive capacity, NFATs and FOXP3 expression in blood and skin Tregs of GV patients (p < 0.05). Furthermore, Harmine and Kaempferol treatment in Tregs increased calcineurin and NFATC1 activity and decreased DYRK1A transcripts in blood and skin Tregs of GV patients(p < 0.05). In-silico analysis revealed that Harmine and Kaempferol might boost Treg suppressive capacity by increasing calcineurin dephosphorylation activity leading to increase NFATs activation and also increase nuclear retention of NFATs by inhibiting DYRK1a phosphorylation activity. Moreover, calcineurin and NFATC1 activity in Tregs were positively correlated with Treg suppressive capacity, NFATC1 and FOXP3 expression (p < 0.05), whereas, DYRK1A transcripts were negatively correlated with Treg suppressive capacity, NFATC1 and FOXP3 expression (p < 0.05). These compounds significantly increased melanocytes’ survival and proliferation in Treg:CD4+/CD8+:SK-Mel-28 cell line co-culture system from GV patients (p < 0.0001). ConclusionsFor the first time the study suggests that Harmine and Kaempferol treated Tregs could control the CD8+ and CD4+T-cells’ proliferation and IFN-γ production, leading to melanocytes’ survival and proliferation. These compounds may serve as novel Treg-based therapeutics for GV; however, in vivo studies are warranted to assess the safety and efficacy of these compounds.

Obesity-induced dysregulation of a unique subset of Tregs promotes skin inflammation

Abstract Obesity is associated with increased skin inflammation and is a major risk factor for psoriasis, raising the question of how obesity disrupts the regulatory mechanisms that keep skin inflammation in check at steady state. We found that skin was enriched with a unique subset of CD4 +Foxp3 +regulatory T cells (Tregs), which is critical to limit IL-17A-mediated psoriatic inflammation. Diet-induced obesity, however, resulted in a significant reduction of this subset of skin Tregs and a corresponding loss of control over IL-17A-mediated inflammation. Mechanistically, this specific skin Treg population preferentially took up elevated levels of long-chain saturated fatty acids during obesity, which led to cellular lipotoxicity and mitochondrial dysfunction. Harnessing the anti-inflammatory property of this unique subset of skin Tregs could have therapeutic potential for obesity-associated inflammatory skin diseases. Supported from grants from NIH/NIDDK (1R01DK128061), National Psoriasis Foundation, and Emory University Research Committee (URC).

058 Human Epithelial Resident Memory Regulatory T Cells

Human resident memory regulatory T cells (Tregs) exist in the normal, noninflamed skin. Except one, all previous studies analyzed skin Tregs using full-thickness human skin. Considering that thick dermis contains more Tregs than thin epidermis, the current understanding of skin Tregs might be biased toward dermal Tregs. Therefore, we sought to determine the phenotype and function of human epidermal and epithelial Tregs. Human epidermis and epithelium were allowed to float on a medium without adding any exogenous cytokines and stimulations for two days at 37 °C.

Characterization of human epithelial resident memory regulatory T cells.

Human resident memory regulatory T cells (Tregs) exist in the normal, noninflamed skin. Except one, all previous studies analyzed skin Tregs using full-thickness human skin. Considering that thick dermis contains more Tregs than thin epidermis, the current understanding of skin Tregs might be biased toward dermal Tregs. Therefore, we sought to determine the phenotype and function of human epidermal and epithelial Tregs. Human epidermis and epithelium were allowed to float on a medium without adding any exogenous cytokines and stimulations for two days and then emigrants from the explants were analyzed. Foxp3 was selectively expressed in CD4+CD103− T cells in the various human epithelia, as it is highly demethylated. CD4+CD103−Foxp3+ cells suppressed proliferation of other resident memory T cells. The generation and maintenance of epithelial Tregs were independent of hair density and Langerhans cells. Collectively, immune-suppressive CD4+CD103−Foxp3+ Tregs are present in the normal, noninflamed human epidermis and mucosal epithelia.

863 Blocking the LFA-1 signaling pathway reverses alopecia areata in C3H/HeJ mice

Alopecia areata (AA) is caused by T cell-mediated autoimmune attack of the hair follicle. Therefore, inhibition of T lymphocyte migration and pathogenic activity represents an attractive therapeutic approach in the treatment of T lymphocyte-mediated autoimmune diseases, including AA. The lymphocyte function antigen-1 (LFA-1) receptor signaling pathway plays a crucial role in T cell activation, migration of T cells to target tissues and formation of the classical cytolytic immune synapse. We previously showed that the intercellular adhesion molecule 1(ICAM-1), one of the major ligands for LFA-1, is upregulated in lesional skin of both human patients and C3H/HeJ mice with AA. We observed that CD44+CD8+effector/memory T cell expressed high levels of LFA-1 within skin draining lymph nodes as well as within AA lesional skin. Here, we investigated the role of LFA-1 signaling pathway in AA using C3H/HeJ mice, and found that blockade of the LFA-1 signaling pathway using either anti-LFA-1 or anti-ICAM-1 mAbs prevented the development of AA in C3H/HeJ skin grafted mice. Immunohistochemical staining of skin biopsies show that anti-LFA-1- or anti-ICAM-1-treated mice have a striking decrease in skin T cell infiltration together with reduced expression of AA-associated markers (MHC-I and MHC-II). Furthermore, we observed that LFA-1 signaling blockade not only reduced CD44+CD8 +effector/memory T cell migration into the skin, but also led to enrichment of Tregs in skin draining lymph nodes. To limit systemic exposure, we topically treated C3H/HeJ AA mice with lifitegrast, a small molecule antagonist of LFA-1, and found that lifitegrast was effective in reversal of AA. Taken together, we demonstrated that LFA-1 plays a crucial role in T cell migration and activation in AA, and that reversal of AA was achieved by local LFA-1 signaling blockade using topical delivery. Our results invite further clinical investigation of LFA-1 pathway inhibition as a therapeutic target in AA treatment.

012 Tissue-specific manipulation of regulatory T cells reveals the skin to be a site of immune tolerance

It is commonly accepted that immune tolerance to self-antigens occurs in the thymus and secondary lymphoid organs. Despite the presence of rich immune microenvironments in non-lymphoid organs, such as skin and gut, it is currently unknown if self-tolerance is actively maintained in these tissues. We developed a novel technique to induce genetic recombination only in regulatory T cells (Tregs) that reside in skin. Cell lineage-tracing revealed that skin Tregs undergo significant attrition and replenishment during their natural life cycle.

Immunohistochemical expression of regulatory T cells (CD4 + CD25 + bright FOXP3 + ) in pemphigus patients.

Pemphigus is a series of autoimmune skin disorders caused by IgG. Regulatory T cells (Tregs) are a subset of CD4+ T cells that mostly block pathogenic immune responses mediated by self-reactive cells; therefore, a lack of Tregs or a malfunction in their activity could lead to a loss of tolerance and the development of autoimmunity. To evaluate the expression of lesional and perilesional Treg markers (CD4 + CD25 + bright FOXP3 + ) in pemphigus patients. Twenty-three pemphigus patients and 20 healthy controls were included in this study. The expression of CD4 , CD25, and Foxp3 was evaluated by immunohistochemistry. There was statistically significant increase in CD4+ T lymphocytes in lesional skin of pemphigus compared to perilesional skin and control group (p-value: 0.001). There was statistically significant decrease in CD25+ and Foxp3+ cells in lesional skin compared to perilesional and control group (p-value: <0.001, 0.025, respectively). The reduction of lesional skin Tregs may play an important role in the pemphigus pathogenesis.

Intestinal inflammation alters the antigen-specific immune response to a skin commensal.

SUMMARYResident microbes in skin and gut predominantly impact local immune cell function during homeostasis. However, colitis-associated neutrophilic skin disorders suggest possible breakdown of this compartmentalization with disease. Using a model wherein neonatal skin colonization by Staphylococcus epidermidis facilitates generation of commensal-specific tolerance and CD4+ regulatory T cells (Tregs), we ask whether this response is perturbed by gut inflammation. Chemically induced colitis is accompanied by intestinal expansion of S. epidermidis and reduces gut-draining lymph node (dLN) commensal-specific Tregs. It also results in reduced commensal-specific Tregs in skin and skin-dLNs and increased skin neutrophils. Increased CD4+ circulation between gut and skin dLN suggests that the altered cutaneous response is initiated in the colon, and resistance to colitis-induced effects in Cd4creIl1r1fl/fl mice implicate interleukin (IL)-1 in mediating the altered commensal-specific response. These findings provide mechanistic insight into observed connections between inflammatory skin and intestinal diseases.

Tissue Tregs and Maintenance of Tissue Homeostasis.

Regulatory T cells (Tregs) specifically expressing Forkhead box P3 (Foxp3) play roles in suppressing the immune response and maintaining immune homeostasis. After maturation in the thymus, Tregs leave the thymus and migrate to lymphoid tissues or non-lymphoid tissues. Increasing evidence indicates that Tregs with unique characteristics also have significant effects on non-lymphoid peripheral tissues. Tissue-resident Tregs, also called tissue Tregs, do not recirculate in the blood or lymphatics and attain a unique phenotype distinct from common Tregs in circulation. This review first summarizes the phenotype, function, and cytokine expression of these Tregs in visceral adipose tissue, skin, muscle, and other tissues. Then, how Tregs are generated, home, and are attracted to and remain resident in the tissue are discussed. Finally, how an increased understanding of these tissue Tregs might guide clinical treatment is discussed.

Regulatory T cells promote innate inflammation after skin barrier breach via TGF-β activation.

Regulatory T cells (Tregs) use multiple mechanisms to attenuate inflammation and prevent autoimmunity. Tregs residing in peripheral (i.e., nonlymphoid) tissues have specialized functions; specifically, skin Tregs promote wound healing, suppress dermal fibrosis, facilitate epidermal regeneration, and augment hair follicle cycling. Here, we demonstrated that skin Tregs were transcriptionally attuned to interact with their tissue environment through increased expression of integrin and TGF-β pathway genes that influence epithelial cell biology. We identified a molecular pathway where skin Tregs license keratinocytes to promote innate inflammation after skin barrier breach. Using a single-cell discovery approach, we identified preferential expression of the integrin αvβ8 on skin Tregs Upon skin injury, Tregs used this integrin to activate latent TGF-β, which acted directly on epithelial cells to promote CXCL5 production and neutrophil recruitment. Induction of this circuit delayed epidermal regeneration but provided protection from Staphylococcus aureus infection across a compromised barrier. Thus, αvβ8-expressing Tregs in the skin, somewhat paradoxical to their canonical immunosuppressive functions, facilitated inflammation acutely after loss of barrier integrity to promote host defense against infection.

M−CSF and prostratin induced Mregs promote immune tolerance in transplanted mice through Arg-1 pathway

ObjectiveRegulatory macrophages (Mregs) are a group of heterogeneous macrophages. These cells could induce immunosuppressive effects through the expression of immune regulatory molecules and cytokines. MethodsThe differentiation of Mregs was induced by treating bone marrow cells with M−CSF and prostratin in vitro. The cell-phenotypes and immunosuppressive function were determined by flow cytometry. Rt-PCR was employed to assess the mechanisms of Mregs. Skin grafted mouse model was used for in vivo validation. ResultsMregs induced by M−CSF + prostratin had a strong inhibitory effect on T cell proliferation and cytokines production. The phenotype of induced bone marrow cells changed towards Mregs. These Mregs could induce the differentiation of Tregs in vivo. Arg-1 expression in these cells were significantly upregulated. Inhibition of arginase (Arg) or arginine supplement significantly reversed the immunosuppressive function. In mice skin-grafted models, adoptive transfer of these Mregs significantly prolonged allograft survival. In mice models, Arg-1 expression significantly elevated on skin grafts cells and Tregs increased in graft tissues. ConclusionsWe successfully developed a Mregs-inducing protocol with the combination of M−CSF and prostratin in vitro. M−CSF + prostratin induced Mregs prevented mice skin graft rejection through upregulating the expression Arg-1.

Dynamic Regulation of the Molecular Mechanisms of Regulatory T Cell Migration in Inflamed Skin.

The presence of regulatory T cells (Tregs) in skin is important in controlling inflammatory responses in this peripheral tissue. Uninflamed skin contains a population of relatively immotile Tregs often located in clusters around hair follicles. Inflammation induces a significant increase both in the abundance of Tregs within the dermis, and in the proportion of Tregs that are highly migratory. The molecular mechanisms underpinning Treg migration in the dermis are unclear. In this study we used multiphoton intravital microscopy to examine the role of RGD-binding integrins and signalling through phosphoinositide 3-kinase P110δ (PI3K p110δ) in intradermal Treg migration in resting and inflamed skin. We found that inflammation induced Treg migration was dependent on RGD-binding integrins in a context-dependent manner. αv integrin was important for Treg migration 24 hours after induction of inflammation, but contributed to Treg retention at 48 hours, while β1 integrin played a role in Treg retention at the later time point but not during the peak of inflammation. In contrast, inhibition of signalling through PI3K p110δ reduced Treg migration throughout the entire inflammatory response, and also in the absence of inflammation. Together these observations demonstrate that the molecular mechanisms controlling intradermal Treg migration vary markedly according to the phase of the inflammatory response.

Colitis alters the antigen-specific response to skin commensal bacteria and predisposes to neutrophilic skin inflammation

Abstract Both gut and skin house microbial communities capable of influencing host immunity. During homeostasis, resident microbes are thought to have a dominant impact on local immune cell function. However, the prevalence of skin disorders among IBD patients suggests that this compartmentalized control may not hold under disease conditions. We hypothesize that an altered immune response to gut-resident microbes during colitis may facilitate excessive inflammation directed at skin commensals. Our lab has previously shown that colonization of neonatal mice with Staphylococcus epidermidis expressing the model antigen 2W (S. epi-2W) results in establishment of tolerance, as denoted by a higher percentage of 2W-specific regulatory T cells (Tregs) in the skin and skin-draining lymph nodes (SDLNs) and fewer skin neutrophils upon later-life S. epi-2W re-exposure. To test whether colitis perturbs tolerance to commensal skin bacteria, we colonized mice with S. epi-2W as neonates and subjected them to colitis as adults in conjunction with re-exposure. Colitic mice exhibited increased skin neutrophils and reduced percentages of S. epi-specific Tregs in skin and SDLNs compared to controls. Notably, no difference in S. epi-specific Tregs was noted in mice subjected to LPS-induced sepsis. Increased intra-intestinal presence of S. epi-2W during colitis indicates initiation of this response in the gut. Consistent with this, adoptive transfer experiments revealed a colitis-induced increase in CD4+ T cell trafficking from gut-draining LN to SDLNs. Recovery of S. epi-specific Tregs in colitic Cd4CreIl1r1flox/flox mice indicates an additional role for circulating IL-1 cytokines in shaping the skin commensal response during colitis.

Intestinal Inflammation Breaks Established Immune Tolerance to a Skin Commensal

Author(s): Merana, Geil Ramvielle | Advisor(s): Lowell, Clifford | Abstract: The gut and skin are major barrier tissues that house microbial communities capable of influencing host immunity. Under homeostatic conditions, resident microbes at each of these two sites are thought to have a dominant impact on local immune cell function. However, the prevalence of neutrophilic skin disorders among patients with Inflammatory Bowel Disease suggests that this compartmentalized control may not hold under disease conditions. We hypothesized that an altered immune response to gut-resident microbes during colitis may facilitate excessive inflammation directed at skin commensals. Using an established model, wherein neonatal colonization by Staphylococcus epidermidis facilitates development of adaptive immune tolerance and enrichment in S. epidermidis-specific CD4+ regulatory T cells (Tregs), we asked whether this tolerance to skin bacteria can be perturbed in the context of gut inflammation. Induction during adulthood of either chemically or genetically-mediated colitis, but not systemic inflammation alone, led to reduced percentages of S. epi-specific Tregs in skin and skin-draining lymph nodes (LN) and an increase in skin neutrophils. Intestinal presence of S. epidermidis and reduced percentages of S. epidermidis-specific Tregs at this site during colitis suggested initiation of this altered response in the gut. Consistent with this, adoptive transfer and photoconversion experiments revealed a colitis-induced increase in CD4+ T cell trafficking from gut-draining LN to skin-draining LN. Recovery in the percentage of S. epidermidis-specific Tregs in colitic Cd4creIl1r1fl/fl mice further indicated a role for circulating IL-1 cytokines in shifting the CD4+ skin commensal response during colitis. Collectively, these results identify a context in which there is breakdown in homeostatic separation of skin and gut host-microbe interactions and provide mechanistic insight into observed connections between inflammatory skin and intestinal diseases.

Antigen Specificity Enhances Disease Control by Tregs in Vitiligo.

Vitiligo is an autoimmune skin disease characterized by melanocyte destruction. Regulatory T cells (Tregs) are greatly reduced in vitiligo skin, and replenishing peripheral skin Tregs can provide protection against depigmentation. Ganglioside D3 (GD3) is overexpressed by perilesional epidermal cells, including melanocytes, which prompted us to generate GD3-reactive chimeric antigen receptor (CAR) Tregs to treat vitiligo. Mice received either untransduced Tregs or GD3-specific Tregs to test the hypothesis that antigen specificity contributes to reduced autoimmune reactivity in vitro and in vivo. CAR Tregs displayed increased IL-10 secretion in response to antigen, provided superior control of cytotoxicity towards melanocytes, and supported a significant delay in depigmentation compared to untransduced Tregs and vehicle control recipients in a TCR transgenic mouse model of spontaneous vitiligo. The latter findings were associated with a greater abundance of Tregs and melanocytes in treated mice versus both control groups. Our data support the concept that antigen-specific Tregs can be prepared, used, and stored for long-term control of progressive depigmentation.

Regulatory T cells in skin coordinate responses to epidermal injury by initiating anti-microbial immunity while delaying tissue repair

Abstract When barrier tissues are breached, two coordinate responses need to occur: 1) clearance of pathogens and 2) repair of damaged epithelium. Regulatory T cells (Tregs) play a major role in skin barrier repair; however, the mechanisms by which they modulate local tissue are unclear. To identify molecular pathways underpinning Treg interactions with their tissue environment, we performed single cell RNA sequencing on Tregs isolated from the skin. Our analysis revealed elevated TGFβ and integrin signaling. Specifically, we found high expression of the latent TGFβ activating integrin, αvβ8. To ascertain the physiological significance of this expression we crossed Foxp3CreERT2 and Itgb8f/fmice to generate an inducible and lineage specific system for deleting Itgb8 in Tregs. Deletion of Itgb8 led to improved epidermal healing following sterile injury. Mechanistically, Treg activation of TGFβ directly induced keratinocytes to produce the myeloid chemoattractant CXCL5, leading to neutrophilic inflammation and delayed epidermal healing. We hypothesized that during barrier injury Tregs harness integrin αvβ8 to initiate innate immune responses that temporarily override tissue reparative signals. To interrogate this hypothesis we epicutaneously infected Treg Itgb8 deleted mice with the bacterial pathogen Staphylococcus aureus. Deleted mice developed an uncontrolled infection consistent with impaired immune responses. These data indicate that activation of TGFβ by skin Tregs in response to tissue injury initiates local anti-microbial immunity. Altogether, our study uncovers a unique ability of skin Tregs to leverage TGFβ signaling to coordinate epithelial repair and innate immunity for optimized tissue healing.