Project description:Current interventions for endometriosis mainly involve hormone therapies but have limited efficacy and unacceptable side effects, due to the lack of selectivity to distinguish between endometriosis and endometrial tissues. Elucidating the molecular mechanism underlying rapid growth of endometrial-like stromal cells, one of the main components of endometriotic lesions, will pave a path for more effective treatment of endometriosis. In the current study, we utilized transcriptome sequencing to compare the transcriptional profiles of endometrial-like stromal cells from endometriosis and endometrial tissues and demonstrated that Homeobox C4 (HOXC4) is preferentially expressed in endometriotic lesions. HOXC4 is indispensable for the proliferation of stromal cells from endometriosis, but not those from endometrial tissues. Mechanistically, HOXC4 acts as a transcription factor to promote the expression of Slit Guidance Ligand 2 (SLIT2) and thereby, increases the p38 MAPK activity via the SLIT2 receptor Roundabout Guidance Receptor 1 (ROBO1). Considering the essential role of the p38 MAPK activity in facilitating the development of ectopic endometrium, our findings strongly support the idea of HOXC4, as well as the SLIT2-ROBO1 axis, being as potential therapeutic targets for endometriosis.
Project description:BACKGROUND. Enhancing NAD+ level by Nicotinamide Riboside (NR) supplementation confer anti-inflammatory effects in human disease, yet the immunoregulatory mechanisms remain unclear. We previously demonstrated ex vivo study that NR blunts CD4+ T cell immune responsiveness in psoriasis. To explore whether these effects occur in vivo, we conducted a randomized, placebo-controlled NR supplementation study in participants with mild-tomoderate- psoriasis. METHODS. Psoriasis participants consumed oral NR supplementation (500 mg twice daily) or matching placebo for 4 weeks. Research bloods were drawn at baseline and at 4 weeks for analysis. In parallel, natural history cohorts of healthy controls and psoriasis participants donated research blood and skin punch biopsies for mechanistic analysis. RESULTS. Oral NR supplementation dampens Th17 immune responsiveness. Bulk RNA-seq of CD4+ cells identified that NR regulated the SLIT-ROBO signaling pathway. Participants on NR showed elevated circulating SLIT2 levels, and NR increased SLIT2 production in skin fibroblasts. Pharmacologic and genetic studies in CD4+ T cells and fibroblasts showed that SLIT2, acting through the ROBO1 receptor, inhibited Rho GTPase signaling, thereby reducing canonical Th17 polarization and fibroblast inflammatory activation. CONCLUSION. NAD+ augmentation confers anti-inflammatory effects in psoriasis through SLIT2/ROBO1-mediated crosstalk between dermal fibroblast and circulating CD4+ T cells, leading to attenuation of Th17-driven inflammation.
Project description:Roundabout (ROBO) 1 and 2 are transmembrane receptors that bind secreted SLIT ligands through their extracellular domains (ECD), and signal through their cytoplasmic domains to modulate the cytoskeleton and regulate cell migration, adhesion, and proliferation. SLIT-ROBO signaling was discovered as a guidance cue for axons in the developing nervous system, but ROBO receptors are expressed by many additional cell types and more broadly regulate organ morphogenesis, as well as cancer and pathological ocular neovascularization. As pharmacological tools to prevent SLIT-ROBOR signaling are lacking, herein we developed human monoclonal antibodies (mAb ) against the ROBO1 and 2 ECD. One antibody that inhibited in vitro SLIT2 signaling through ROBO1/2 reduced ocular neovascularization in two pathological models in vivo. Single cell RNA sequencing revealed that antibody treatment affected several cell types relevant to angiogenesis, including endothelial cells, pericytes, and a heterogeneous population of myeloid cells. mAb treatment improved Blood-Retina Barrier integrity and prevented pathological pericyte activation. SLIT-ROBO signaling inhibition prevented pathological activation of myeloid cells, which was phenocopied by both myeloid cell specific ablation of Robo1 and 2 and by knockout of the downstream effector Pi3kγ. Anti-ROBO1/2 blocking antibodies may thus provide a new promising strategy to combat inflammation in blinding eye diseases.
