Identification of genes associated with TGF-beta/Smad3-mediated renal inflammation and fibrosis by RNA sequencing
ABSTRACT: In this study, we employed high-throughput RNA sequencing (RNA-Seq) to identify the Smad3-dependent lncRNAs related to renal inflammation and fibrosis in Smad3 knockout (KO) mouse models of unilateral ureteral obstructive nephropathy (UUO) and immunologically-induced anti-glomerular basement membrane glomerulonephritis (anti-GBM GN). 12 kidney tissue samples of Smad3 KO/WT mice from normal control, UUO at day 5 or anti-GBM GN at day 10 models (n=2 in each group) for whole transcriptome RNA-sequencing.
Project description:We investigated a glomerulonephritis (GN) model in rats induced by nephrotoxic serum (NTS) which contains antibodies against the glomerular basement membrane (GBM). The anti-GBM GN model in rats is widely used since its biochemical and histopathological characteristics are similar to crescentic nephritis and Goodpasture's disease in humans. Male Wistar Kyoto (WKY) and Sprague Dawley (SD) rats were dosed once with 1, 2.5 and 5 ml/kg nephrotoxic serum (NTS) or 1.5 and 5 ml/kg NTS, respectively. GN and tubular damage were observed histopathologically in all treated rats after 14 days. To obtain insight into molecular processes during GN pathogenesis, mRNA expression was investigated in WKY and SD kidneys. The immunopathological processes during GN are still not fully understood and likely involve both innate and adaptive immunity. In the present study, several hundred mRNAs were found deregulated, which functionally were mostly associated with inflammation and regeneration. The β-chain of the major histocompatibility complex class II RT1.B (Rt1-Bb) and complement component 6 (C6) were identified as two mRNAs differentially expressed between WKY and SD rat strains which could be related to known different susceptibilities to NTS of different rat strains; both were increased in WKY and decreased in SD rats. Increased Rt1-Bb expression in WKY rats could indicate a stronger and more persistent cellular reaction of the adaptive immune system in this strain, in line with findings indicating adaptive immune reactions during GN. The complement cascade is also known to be essential for GN development, especially terminal cascade products like C6. Two different rat strains (WKY and SD) were dosed with different doses of NTS and after 14 days rats were euthanized and kidneys were removed for RNA extraction and hybridization on Affymetrix microarrays. We sought to analyze the deregulation of gene expression during NTS-induced glomerulonephritis and to compare the effect in the two rat strains.
Project description:Increased export of transglutaminase-2 (TG2) by tubular epithelial cells (TECs) into the surrounding interstitium modifies the extracellular homeostatic balance leading to fibrotic membrane expansion. Although silencing of extracellular TG2 ameliorates progressive kidney scarring in animal models of chronic kidney disease, the pathway through which TG2 is secreted from TECs and contributes to disease progression has not been elucidated. In this study, we developed a global proteomic approach to identify binding partners of TG2 responsible for TG2 externalization in kidneys subjected to unilateral ureteric obstruction, using TG2-knockout kidneys as negative controls. We report a robust and unbiased analysis of the membrane interactome of TG2 in fibrotic kidneys relative to the entire proteome post-UUO detected by SWATH-mass spectrometry.
Project description:Tubulointerstitial fibrosis is the final common result of a variety of progressive injuries leading to chronic renal failure. Transforming growth factor-beta (TGF-beta) is reportedly upregulated in response to injurious stimuli such as unilateral ureteral obstruction (UUO), causing renal fibrosis associated with epithelial-mesenchymal transition (EMT) of the renal tubules and synthesis of extracellular matrix. We now show that mice lacking Smad3 (Smad3ex8/ex8), a key signaling intermediate downstream of the TGF-beta receptors, are protected against tubulointerstitial fibrosis following UUO as evidenced by blocking of EMT and abrogation of monocyte influx and collagen accumulation. Culture of primary renal tubular epithelial cells from wild-type or Smad3-null mice confirms that the Smad3 pathway is essential for TGF-beta1-induced EMT and autoinduction of TGF-beta1. Moreover, mechanical stretch of the cultured epithelial cells, mimicking renal tubular distention due to accumulation of urine after UUO, induces EMT following Smad3-mediated upregulation of TGF-beta1. Exogenous bone marrow monocytes accelerate EMT of the cultured epithelial cells and renal tubules in the obstructed kidney after UUO dependent on Smad3 signaling. Together the data demonstrate that the Smad3 pathway is central to the pathogenesis of interstitial fibrosis and suggest that inhibitors of this pathway may have clinical application in the treatment of obstructive nephropathy.
Project description:Obstructive nephropathy is the end result of a variety of diseases that block drainage from the kidney(s). Transforming growth factor-β1 (TGF-β1)/Smad3-driven renal fibrosis is the common pathogenesis of obstructive nephropathy. In this study, we identified petchiether A (petA), a novel small-molecule meroterpenoid from Ganoderma, as a potential inhibitor of TGF-β1-induced Smad3 phosphorylation. The obstructive nephropathy was induced by unilateral ureteral obstruction (UUO) in mice. Mice received an intraperitoneal injection of petA/vehicle before and after UUO or sham operation. An in vivo study revealed that petA protected against renal inflammation and fibrosis by reducing the infiltration of macrophages, inhibiting the expression of proinflammatory cytokines (interleukin-1β and tumour necrosis factor-α) and reducing extracellular matrix deposition (α-smooth muscle actin, collagen I and fibronectin) in the obstructed kidney of UUO mice; these changes were associated with suppression of Smad3 and NF-κB p65 phosphorylation. Petchiether A inhibited Smad3 phosphorylation in vitro and down-regulated the expression of the fibrotic marker collagen I in TGF-β1-treated renal epithelial cells. Further, we found that petA dose-dependently suppressed Smad3-responsive promoter activity, indicating that petA inhibits gene expression downstream of the TGF-β/Smad3 signalling pathway. In conclusion, our findings suggest that petA protects against renal inflammation and fibrosis by selectively inhibiting TGF-β/Smad3 signalling.
Project description:TGF-?1, via Smad-dependent or Smad-independent signaling, has a central role in the pathogenesis of renal fibrosis. This pathway has been recognized as a potential target for antifibrotic therapy. Here, we identified GQ5, a small molecular phenolic compound isolated from the dried resin of Toxicodendron vernicifluum, as a potent and selective inhibitor of TGF-?1-induced Smad3 phosphorylation. In TGF-?1-stimulated renal tubular epithelial cells and interstitial fibroblast cells, GQ5 inhibited the interaction of Smad3 with TGF-? type I receptor (T?RI) by blocking binding of Smad3 to SARA, suppressed subsequent phosphorylation of Smad3, reduced nuclear translocation of Smad2, Smad3, and Smad4, and downregulated the transcription of major fibrotic genes such as ?-smooth muscle actin (?-SMA), collagen I, and fibronectin. Notably, intraperitoneal administration of GQ5 in rats immediately after unilateral ureteral obstruction (UUO) selectively inhibited Smad3 phosphorylation in UUO kidneys, suppressed renal expression of ?-SMA, collagen I, and fibronectin, and resulted in impressive renal protection after obstructive injury. Late administration of GQ5 also effectively attenuated fibrotic lesions in obstructive nephropathy. In conclusion, our results suggest that GQ5 hinders renal fibrosis in rats by selective inhibition of TGF-?1-induced Smad3 phosphorylation.
Project description:Previous studies have suggested that Klotho provides reno-protection against unilateral ureteral obstruction (UUO)-induced renal tubulointerstitial fibrosis (RTF). Because the existing studies are mainly performed using heterozygous Klotho mutant (HT) mice, we focused on the effect of UUO on homozygous Klotho mutant (kl/kl) mice. UUO kidneys from HT mice showed a significantly higher level of RTF and TGF-?/Smad3 signaling than wild-type (WT) mice, whereas both were greatly suppressed in kl/kl mice. Primary proximal tubular epithelial culture cells isolated from kl/kl mice showed no suppression in TGF-?1-induced epithelial mesenchymal transition (EMT) compared to those from HT mice. In the renal epithelial cell line NRK52E, a large amount of inorganic phosphate (Pi), FGF23, or calcitriol was added to the medium to mimic the in vivo homeostasis of kl/kl mice. Neither Pi nor FGF23 antagonized TGF-?1-induced EMT. In contrast, calcitriol ameliorated TGF-?1-induced EMT in a dose dependent manner. A vitamin D3-deficient diet normalized the serum 1,25 (OH)2 vitamin D3 level in kl/kl mice and enhanced UUO-induced RTF and TGF-?/Smad3 signaling. In conclusion, the alleviation of UUO-induced RTF in kl/kl mice was due to the TGF-?1 signaling suppression caused by an elevated serum 1, 25(OH)2 vitamin D3.
Project description:Fibrosis is a common pathway in the progression of chronic kidney disease. Extracellular matrix deposition from myofibroblasts causes scarring, tissue stiffness and organ failure. This submission studies the role of Sex determining region Y-box 9 (SOX9) in kidney fibrosis.
Project description:Profiling of miRNA expression in mouse SHAM kidneys 9–12 weeks old male C57BL/6 mice were purchased from Charles River. Mice underwent anesthesia by intraperitoneal injection of pentobarbital (50 mg/kg body weight) and were subjected to Unilateral Ureteral Obstruction (UUO). After standard laparotomy, the left proximal ureter was exposed and ligated with 4-0 silk at two points. The sham operation consisted of a similar identification of the left ureter without ligation. Treated (S numbers) and non-treated (C numbers) mice miRNA expressions were then compared.
Project description:Transforming growth factor ? (TGF-?)/Smad3 signaling plays a role in tissue fibrosis. We report here that Erbb4-IR is a novel long non-coding RNA (lncRNA) responsible for TGF-?/Smad3-mediated renal fibrosis and is a specific therapeutic target for chronic kidney disease. Erbb4-IR was induced by TGF-?1 via a Smad3-dependent mechanism and was highly upregulated in the fibrotic kidney of mouse unilateral ureteral obstructive nephropathy (UUO). Silencing Erbb4-IR blocked TGF-?1-induced collagen I and alpha-smooth muscle actin (?-SMA) expressions in vitro and effectively attenuated renal fibrosis in the UUO kidney by blocking TGF-?/Smad3 signaling. Mechanistic studies revealed that Smad7, a downstream negative regulator of TGF-?/Smad signaling, is a target gene of Erbb4-IR because a binding site of Erbb4-IR was found on the 3' UTR of Smad7 gene. Mutation of this binding site prevented the suppressive effect of Erbb4-IR on the Smad7 reporter activity; in contrast, overexpression of Erbb4-IR largely inhibited Smad7 but increased collagen I and ?-SMA transcriptions. Thus, kidney-specific silencing of Erbb4-IR upregulated renal Smad7 and thus blocked TGF-?/Smad3-mediated renal fibrosis in vivo and in vitro. In conclusion, the present study identified that Erbb4-IR is a novel lncRNA responsible for TGF-?/Smad3-mediated renal fibrosis by downregulating Smad7. Targeting Erbb4-IR may represent a precise therapeutic strategy for progressive renal fibrosis.
Project description:Overexpression of transforming growth factor beta (TGF-beta) has been shown to play pathogenic roles in progression of renal fibrosis, and the severity of tubulointerstitial fibrosis correlates better with renal function than the severity of glomerulosclerosis. Smad proteins are signaling transducers downstream from TGF-beta receptors. Three families of Smad proteins have been identified: receptor-regulated Smad2 and Smad3, common partner Smad4, and inhibitory Smad7 (part of a negative-feedback loop). We investigated Smad-mediated TGF-beta signaling pathway and regulatory mechanisms of inhibitory Smad7 in unilateral ureteral obstruction (UUO) kidneys in mice, a model of progressive tubulointerstitial fibrosis. Compared with sham-operated kidneys, the level of Smad7 protein, but not mRNA, decreased progressively in UUO kidneys, whereas immunoreactivity for nuclear phosphorylated Smad2 and Smad3 and renal fibrosis were inversely increased. Furthermore, we demonstrated that both the degradation and ubiquitination activity of Smad7 protein were increased markedly in UUO kidneys compared with sham-operated ones. We also found that both Smurf1 and Smurf2 (Smad ubiquitination regulatory factors), which are E3 ubiquitin ligases for Smad7, were increased and that they interacted with Smad7 in UUO kidneys. Our results suggest that the reduction of Smad7 protein resulting from enhanced ubiquitin-dependent degradation plays a pathogenic role in progression of tubulointerstitial fibrosis.