Exogenous miR-29a Attenuates Muscle Atrophy and Kidney Fibrosis in Unilateral Ureteral Obstruction Mice

Abstract

Renal fibrosis leads to end-stage renal disease, but antifibrotic drugs are difficult to develop. Chronic kidney disease often results in muscle wasting, and thereby increases morbidity and mortality. In this work, adeno-associated virus (AAV)mediated overexpressing miR-29a was hypothesized to counteract renal fibrosis and muscle wasting through muscle-kidney crosstalk in unilateral ureteral obstruction (UUO) mice. miR-29a level was downregulated in the kidney and skeletal muscle of UUO mice. The secretion of exosome-encapsulated miR-29a increased in cultured skeletal muscle satellite cells and HEK293 renal cells after stimulation with serum from UUO mice. This result was confirmed by qPCR and microRNA deep sequencing in the serum exosomes of mice with obstructed ureters. A recombinant AAV-miR-29a was generated to overexpress miR-29a and injected into the tibialis anterior muscle of the mice 2 weeks before UUO surgery. AAV-miR-29a abrogated the UUO-induced upregulation of YY1 and myostatin in skeletal muscles. Renal fibrosis was also partially improved in the UUO mice with intramuscular AAV-miR-29a transduction. AAV-miR-29a overexpression reversed the increase in transforming growth factor b, fibronectin, alpha-smooth muscle actin, and collagen 1A1 and 4A1 levels in the kidney of UUO mice. AAV-green fluorescent protein was applied to trace the AAV route in vivo, and fluorescence was significantly visible in the injected/uninjected muscles and in the kidneys. In conclusion, intramuscular AAV-miR-29a injection attenuates muscle wasting and ameliorates renal fibrosis by downregulating several fibrotic-related proteins in UUO mice.

The role of miR‐29 family in disease

“…A disintegrin and metalloproteinases (ADAMs) are involved in renal fibrosis and TGF‐β/Smad2/3 signaling upregulates Adam 10, 12, 17, 19 expression in renal cells and in unilateral ureteral obstruction models of renal fibrosis 35 . The increase in Adams12 and 19 expression correlated strongly with a decrease in miR‐29s expression and the overexpression of miR‐29s blocked TGF‐β‐mediated upregulation of Adam12 and Adam19 gene expression and improve renal fibrosis 35,36,176 . These studies strongly suggest ADAMs are involved in renal fibrosis and are regulated by both miR‐29s and TGF‐β making thempotential therapeutic targets for the prevention of renal fibrosis.…”

Extracellular Vesicles in Organ Fibrosis: Mechanisms, Therapies, and Diagnostics

“…Several lines of evidence suggest that miR-29a is an important antifibrotic agent in the kidney. Expression of miR-29a was reduced in the kidney in rodent UUO models [ 149 ] and in urinary exosomes from CKD patients [ 150 , 151 , 152 ], while renal fibrosis was suppressed after administration of AAV-miR-29 in mice with UUO or DN [ 153 ]. Muscle satellite cell exosomes engineered to contain enriched levels of miR-29a and to elaborate a surface RVG-moiety that targeted acetylcholine receptors in the kidney were therapeutic after intramuscular injection in the UUO model [ 154 ].…”

“…Levels of vitronectin in urine and urinary EVs [ 161 ] or of miR-21 in plasma EVs [ 162 ] were proposed as biomarkers for post-kidney transplantation patients with a high incidence of tubulointerstitial fibrosis. Finally, miR-29a was elevated in serum EVs from mice with UUO [ 153 ] and plasma-derived exosomal miRs in rats that had undergone 5/6th partial nephrectomy or two-kidney-one-clip were associated with pathways of fibrosis and injury and could be discriminated from free plasma miRs [ 163 ].…”

Roles of Exosomes in Cardiac Fibroblast Activation and Fibrosis

“…miR-29 expression was downregulated following myocardial infarction and after treatment of isolated heart fibroblasts with TGF-β [ 112 ]. Overexpression of miR-29 inhibited the pro-fibrotic response in isolated cardiac fibroblasts and in animal models [ 113 , 114 ]. These studies focused on endogenous miR-29 in cardiac fibroblasts; however, recent studies have shown that miR-29 carried by exosomes is able to reduce skeletal muscle atrophy and kidney fibrosis in a unilateral ureteral obstruction-induced model of kidney disease [ 114 ].…”