Klotho gene delivery ameliorates renal hypertrophy and fibrosis in streptozotocin-induced diabetic rats by suppressing the Rho-associated coiled-coil kinase signaling pathway

Abstract

The present study aimed to investigate whether klotho gene delivery attenuated renal hypertrophy and fibrosis in streptozotocin-induced diabetic rats. A recombinant adeno-associated virus (rAAV) carrying mouse klotho full-length cDNA (rAAV.mKL), was constructed for in vivo investigation of klotho expression. Diabetes was induced in rats by a single tail vein injection of 60 mg/kg streptozotocin. Subsequently, the diabetic rats received an intravenous injection of rAAV.mKL, rAAV.green fluorescent protein (GFP) or phosphate-buffered saline (PBS). The Sprague-Dawley rat group received PBS and served as the control group. After 12 weeks, all the rats were sacrificed and ELISA, immunohistochemical and histological analyses, fluorescence microscopy, semi-quantitative reverse transcription-polymerase chain reaction and western blottin were performed. A single dose of rAAV.mKL was found to prevent the progression of renal hypertrophy and fibrosis for at least 12 weeks (duration of study). Klotho expression was suppressed in the diabetic rats, but was increased by rAAV.mKL delivery. rAAV.mKL significantly suppressed diabetes-induced renal hypertrophy and histopathological changes, reduced renal collagen fiber generation and decreased kidney hypertrophy index. In addition, rAAV.mKL decreased the protein expression levels of fibronectin and vimentin, while it downregulated the mRNA expression and activity of Rho-associated coiled-coil kinase (ROCK)I in the kidneys of the diabetic rats. These results indicated that klotho gene delivery ameliorated renal hypertrophy and fibrosis in diabetic rats, possibly by suppressing the ROCK signaling pathway. This may offer a novel approach for the long-term control and renoprotection of diabetes.

Reduction of cellular stress is essential for Fibroblast growth factor 1 treatment for diabetic nephropathy

“…Our previous study had also demonstrated that FGF1 treatment blocks ER stress and consequently apoptosis of DA neuron during development of Parkinson's disease (PD) . Moreover, FGF23, the FGF family, has also an anti‐oxidative stress activity . Thus, we hypothesized that FGF1‐associated glucose decreases and subsequent reduction of cellular stress is the another potential cellular molecule mechanisms mediating FGF1 treatment forDN.…”

“…17 Moreover, FGF23, the FGF family, has also an anti-oxidative stress activity. 18,19 Thus, we hypothesized that FGF1-associated glucose decreases and subsequent reduction of cellular stress is the another potential cellular molecule mechanisms mediating FGF1 treatment forDN.…”

The cytoskeleton as a novel target for treatment of renal fibrosis

“…Expression of klotho via adeno-associated virus gene delivery downregulated ROCK1 activity and reduced fibrosis in the streptozotocin-induced diabetes rat model (Deng et al, 2015). Increased klotho staining was seen in tubular epithelial cells, suggesting that the protective effect involved these cells; however, renal function was not assessed in this study.…”

Nano-sized carriers in gene therapy for renal fibrosisin vivo

“…AAV vectors designed for expression of suppressor of cytokine signaling (SOCS)2 over-expressed SOCS2 in the kidney and inhibited renal fibrosis and inflammation in a rat model of diabetic nephropathy [42]. The inhibitory effects on renal fibrosis by modulation of expression of the following genes by exogenous genes delivered with AAV vectors have been reported: adrenomedullin [43]; endothelial nitric oxide synthase [44]; Klotho [45]; cytochrome P450 2J2 [46]; and angiotensin II receptor 1 [47]. …”