GSE178109
Indian Hedgehog release from inflamed epithelia links TNF-alpha   to organ fibrosis
In chronic kidney disease (CKD) and with ageing, individuals lose regenerative capacity after renal injury and are predisposed to progressive fibrosis and cardiovascular disease.  With ageing and CKD increased numbers of activated leukocytes are present in the circulation and within the kidney where they correlate with progressive fibrosis.   The potential role of activated leukocytes in mediating progressive renal and systemic fibrosis remains incompletely understood.  Here, we show that tumour necrosis factor alpha (TNFa) released with injury and aging promotes renal and cardiac fibrosis. We identify a Ubiquitin D expressing population of TNFa induced inflammatory proximal tubular epithelia (iPT) responsible for Indian Hedgehog release in aged and fibrotic kidneys. Indian Hedgehog production by iPT cells activates canonical Hedgehog signalling in Gli1+ stromal cells leading to activation, proliferation and fibrosis deposition.  Our data links the immune activation seen in aging and chronic kidney disease to cardio-renal fibrosis. This provides multiple targets for antifibrotic therapies which we validate in murine models of aging and kidney disease. Overall design: Unbiased examination of single cell RNA-seq of injured murine kidney, control kidneys and BULK RNA-SEQ of IHH KO kidneys, paired controls, uninjured controls, post nephrectomy contralatearl kidneys , and post iri contralateral