Fibroblast growth factor 21 alleviates unilateral ureteral obstruction-induced renal fibrosis by inhibiting Wnt/β-catenin signaling pathway

Pemafibrate ameliorates renal injury through induction of FGF21 and ketone body production in male mice

Chronic kidney disease is a life-threatening disease worldwide. PPARα is a crucial transcriptional regulator of lipid metabolism and inflammation. Here, we examine whether a novel selective PPARα modulator, pemafibrate modulates renal injury in a model of unilateral ureteral obstruction (UUO). Administration of pemafibrate to wild-type (WT) mice led to reduction of renal dysfunction and fibrosis after UUO with accompanying increases in plasma levels of fibroblast growth factor (FGF) 21 and ketone body β-hydroxybutyrate (BHB). Treatment of WT mice with FGF21 or BHB precursor resulted in attenuation of renal fibrotic and inflammatory responses after UUO. Treatment of proximal tubular cells with FGF21 or BHB reduced expression of epithelial-mesenchymal transition markers. These findings suggest that pemafibrate could ameliorate renal damage, at least in part, by its abilities to increase the production of FGF21 and BHB.

Adipose mesenchymal stem cell-derived extracellular vesicles alleviate renal fibrosis by reducing epithelial-mesenchymal transition via the FOXS1/Wnt/β-catenin signaling pathway

BACKGROUND

Adipose mesenchymal stem cells (ADSCs) exert beneficial effects on kidney disease through a paracrine mechanism. However, the specific molecular mechanisms by which ADSCs treat renal fibrosis are not yet fully understood. Therefore, it is crucial to clarify the therapeutic effects of ADSC-derived extracellular vesicles (ADSC-EVs) on the progression of renal fibrosis and their underlying mechanisms.

METHODS

We investigated the therapeutic effects of ADSC-EVs on renal fibrosis both in vivo and in vitro. Key genes and signaling pathways were identified with RNA sequencing analysis of HK-2 cells. The role and underlying mechanism of the FOXS1/Wnt/β-catenin pathway in mediating antifibrotic effects were also verified.

RESULTS

In vivo, We found that ADSC-EV treatment significantly improves renal fibrosis in unilateral ureteral obstruction (UUO)-induced renal fibrosis mice models. And in vitro, our data suggested that ADSC-EVs can reduce epithelial-mesenchymal transition (EMT) to inhibit fibrosis in transforming growth factor-β1 (TGF-β1)-treated HK-2 cells. The RNA sequencing results showed that FOXS1 was the primary gene involved in ADSC-EV treatment of renal fibrosis. RT-qPCR suggested that ADSC-EV treatment reversed elevated FOXS1 level both in TGF-β1-treated HK-2 cells and UUO-induced renal fibrosis mice models. Moreover, Western blot analysis confirmed that ADSC-EVs alleviate renal fibrosis and EMT by inhibiting the expression of FOXS1 in HK-2 cells treated with TGF-β1. Furthermore, overexpression of FOXS1 in HK-2 cells could promote the occurrence of fibrosis and knockdown of FOXS1 could reduce the occurrence of fibrosis. Finally, ADSC-EVs may exert these effects via FOXS1-mediated activation of the Wnt/β-catenin pathway.

CONCLUSION

Taken together, we have confirmed that ADSC-EVs alleviate renal fibrosis by reducing EMT via the FOXS1/Wnt/β-catenin signaling pathway.

Efficacy of Oroxylin A in ameliorating renal fibrosis with emphasis on Sirt1 activation and TGF-β/Smad3 pathway modulation

Introduction

Renal fibrosis poses a serious threat to human health. At present, there are few types of traditional Chinese medicine used to treat this disease, and Oroxylin A (OA), as a natural product with multiple biological activities, is expected to be used for the treatment of renal fibrosis.

Methods

The tolerance of osteoarthritis and its impact on renal fibrosis were studied through ADMET, Lipinski's filter, establishment of a unilateral ureteral obstruction (UUO) model, and molecular docking.

Results

OA has good drug tolerance. Compared with the sham group, UUO mice that did not receive OA treatment showed severe tubular dilation and atrophy, extracellular matrix (ECM) deposition, and inflammatory cell infiltration in their kidneys, while OA-treated mice showed significant improvement in these symptoms. OA treatment remarkably restrained the accumulation of fibronectin and α-SMA. Moreover, OA treatment remarkably decreased the abnormal upregulation of inflammatory factors (IL-1β, IL-6, and TNF-α) in the obstructed kidney of UUO mice. Sirtuin1 (Sirt1) expression was markedly diminished in the kidneys of UUO mice and TGF-β1-induced HK-2 cells, whereas this reduction was largely reversed after OA treatment. The results support that OA exerts antifibrotic effects partly through the promotion of the activity of Sirt1. In in vitro results, OA treatment markedly inhibited the activation of Smad3 in UUO mice, thereby ameliorating renal fibrosis. OA could form hydrogen bonds with key the amino acid ASN226 in Sirt1, thereby activating Sirt1, which might also be the reason why OA could resist renal fibrosis.

Discussion

Our study indicated that OA might exert anti-renal fibrosis effects through the activation of Sirt1 and the suppression of the TGF-β/Smad3 signaling pathway.

FGF21 Inhibits Hypoxia/Reoxygenation-induced Renal Tubular Epithelial Cell Injury by Regulating the PPARγ/NF-κB Signaling Pathway

As a predominant trigger of acute kidney injury, renal ischemia-reperfusion injury can cause permanent renal impairment, and the effective therapies are lacking. Fibroblast growth factor 21 (FGF21) plays a critical regulatory role in a variety of biological activities. This study was conducted to explore the functional of FGF21 in renal ischemia-reperfusion injury and to discuss the hidden reaction mechanism. To simulate renal ischemia-reperfusion injury in vitro, HK2 cells were induced by hypoxia/reoxygenation (H/R). The effects of FGF21 on H/R-induced HK2 cell viability were evaluated utilizing cell counting kit-8 (CCK-8). The levels of lactate dehydrogenase (LDH) and inflammatory cytokines in H/R-induced HK2 cells were assessed by means of LDH assay and enzyme-linked immunosorbent assay (ELISA). The levels of oxidative stress markers were appraised with corresponding assay kits and western blot was applied to estimate the expressions of oxidative stress-related proteins. The apoptosis of H/R-induced HK2 cells was assessed by virtue of flow cytometry. The expressions of apoptosis- and PPARγ/NF-κB signaling pathway-related proteins were evaluated with western blot. To discuss the reaction mechanism of PPARγ/NF-κB pathway in H/R-induced HK2 cells, PPARγ inhibitor GW9662 was employed to treat cells and the above experiments were then conducted again. This study found that FGF21 treatment inhibited the inflammatory response, oxidative stress and apoptosis in H/R-induced HK2 cells. Moreover, FGF21 regulated PPARγ/NF-κB signaling pathway and GW9662 partially reversed the impacts of FGF21 on the inflammatory response, oxidative stress and apoptosis in H/R-exposed HK2 cells. Collectively, FGF21 protected against H/R-induced renal tubular epithelial cell injury by regulating the PPARγ/NF-κB signaling pathway.