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Fate Tracing Reveals the Pericyte and Not Epithelial Origin of Myofibroblasts in Kidney Fibrosis
Deficient Autophagy Results in Mitochondrial Dysfunction and FSGS
Cellular and Molecular Mechanisms in Kidney Fibrosis
Anti-microRNA-21 Oligonucleotides Prevent Alport Nephropathy Progression by Stimulating Metabolic Pathways
LRP-6 is a Coreceptor for Multiple Fibrogenic Signaling Pathways in Pericytes and Myofibroblasts That are Inhibited by DKK-1
Dicer1 Activity in the Stromal Compartment Regulates Nephron Differentiation and Vascular Patterning During Mammalian Kidney Organogenesis

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Pericyte MyD88 and IRAK4 control inflammatory and fibrotic responses to tissue injury.

Related Articles

Pericyte MyD88 and IRAK4 control inflammatory and fibrotic responses to tissue injury.

J Clin Invest. 2017 Jan 03;127(1):321-334

Authors: Leaf IA, Nakagawa S, Johnson BG, Cha JJ, Mittelsteadt K, Guckian KM, Gomez IG, Altemeier WA, Duffield JS

Abstract
Fibrotic disease is associated with matrix deposition that results in the loss of organ function. Pericytes, the precursors of myofibroblasts, are a source of pathological matrix collagens and may be promising targets for treating fibrogenesis. Here, we have shown that pericytes activate a TLR2/4- and MyD88-dependent proinflammatory program in response to tissue injury. Similarly to classic immune cells, pericytes activate the NLRP3 inflammasome, leading to IL-1β and IL-18 secretion. Released IL-1β signals through pericyte MyD88 to amplify this response. Unexpectedly, we found that MyD88 and its downstream effector kinase IRAK4 intrinsically control pericyte migration and conversion to myofibroblasts. Specific ablation of MyD88 in pericytes or pharmacological inhibition of MyD88 signaling by an IRAK4 inhibitor in vivo protected against kidney injury by profoundly attenuating tissue injury, activation, and differentiation of myofibroblasts. Our data show that in pericytes, MyD88 and IRAK4 are key regulators of 2 major injury responses: inflammatory and fibrogenic. Moreover, these findings suggest that disruption of this MyD88-dependent pathway in pericytes might be a potential therapeutic approach to inhibit fibrogenesis and promote regeneration.

PMID: 27869651 [PubMed - indexed for MEDLINE]