WISP1 silencing confers protection against epithelial-mesenchymal transition of renal tubular epithelial cells in rats via inactivation of the wnt/β-catenin signaling pathway in uremia

Silencing of METTL3 prevents the proliferation, migration, epithelial-mesenchymal transition, and renal fibrosis of high glucose-induced HK2 cells by mediating WISP1 in m6A-dependent manner

Diabetic nephropathy (DN) is one of the most serious complications in diabetic patients. And m6A modifications mediated by METTL3 are involved multiple biological processes. However, the specific function and mechanism of METTL3 in DN remains unclear. DN model mice were first established with streptozotocin, and WISP1 expression was confirmed by qRT-PCR. Then the influences of WISP1 or/and METTL3 on the proliferation, migration, and epithelial-mesenchymal transition (EMT) and fibrosis-related proteins of high glucose (HG)-induced HK2 cells or HK2 cells were tested through CCK-8, wound healing, and western blot. We first revealed that WISP1 was highly expressed in renal tissues of DN model mice and HG-induced HK2 cells. Functionally, WISP1 or METTL3 silencing could weaken the proliferation, migration, EMT, and fibrosis of HG-treated HK2 cells, and WISP1 or METTL3 overexpression could induce the proliferation, migration, EMT, and fibrosis of HK2 cells. Additionally, METTL3 silencing could decrease WISP1 m6A modification, and silencing of METTL3 also could notably suppress the biological functions of HG-induced HK2 cells by downregulating WISP1. Silencing of METTL3 prevents DN development process by decreasing WISP1 with m6A modification pattern. Therefore, we suggest that METTL3/WISP1 axis might be a novel therapeutic target for DN.

Identification of an unrecognized circRNA associated with development of renal fibrosis

Backgroud: Renal fibrosis is the common characteristic of chronic kidney disease. Circular RNA plays an essential role in the occurrence and development of Renal fibrosis, but its regulative mechanism remains elusive. Methods: The animal and cell model of Renal fibrosis was established, and RNA-sequencing and real-time polymerase chain reaction (qRT-PCR) experiments were implemented. Subsequently, experiments for detecting apoptosis and proliferation of cell, were carried out, and the isobaric tags for relative and absolute quantification proteomics analyses were performed accordingly. Results: It was found that a newly discovered Circular RNA (circRNA_0002158), is highly expressed in kidneys or cells with fibrosis, implying that this Circular RNA might be associated with the occurrence and development of Renal fibrosis. Subsequently, the overexpression and knockdown of circRNA_0002158 were conducted in the human kidney epithelial cell line (HK-2) cells, and the results indicated that the circRNA_0002158 could inhibit apoptosis, and promote proliferation of cells. The kidney injury-related factors, including Fibronectin and plasminogen activator inhibitor-1 (PAI-1), were decreased in HK-2 cells with overexpression of circRNA_0002158, while the results were reversed in cells with knockdown of circRNA_0002158. Finally, to explore the regulative mechanism of circRNA_0002158, the iTRAQ proteomics analyses were implemented for the cell samples with OE of circRNA_0002158 and its control, it showed that multiple genes and functional pathways were associated with the occurrence and development of Renal fibrosis. Conclusion: CircRNA_0002158 is associated with regulating Renal fibrosis, and may contribute to ameliorating the progression of Renal fibrosis in the future.

CircRNA_33702 Promotes Renal Fibrosis by Targeting the miR-29b-3p/WNT1-Inducible Signaling Pathway Protein 1 Pathway

Growing evidence suggest that circular RNAs (circRNAs) are critical mediators in renal diseases. However, there have been very few reports about the role of circRNAs in renal fibrosis. In this study, circRNA_33702 was found to be upregulated, both in unilateral ureteral obstruction (UUO) mice and in TGF-β1-treated Boston University mouse proximal tubule cells. Furthermore, hsa_circ_0026331, homologous with mmu_circ_33702, was found to be upregulated in TGF-β1-treated HK-2 cells. Although knockdown of circRNA_33702 or hsa_circ_0026331 was shown to relieve the TGF-β1-induced expression of collagen I, collagen III, and fibronectin, overexpression of circRNA_33702 was found to exert an inhibitory effect on the expression of the same genes. Mechanistically, circRNA_33702 was demonstrated to bind directly with miR-29b-3p and inhibit its expression. MiR-29b-3p mimic was shown to inhibit the TGF-β1-induced expression of collagen I, collagen III, and fibronectin. Moreover, WNT1-inducible signaling pathway protein 1 (WISP1) was identified as a target of miR-29b-3p, and the expression of WISP1 was observed to be repressed by miR-29b-3p. Notably, knockdown of circRNA_33702 was found to attenuate the expression of collagen I, collagen III, and fibronectin by inhibiting the expression of WISP1, and the observed inhibitory effect can be reversed by miR-29b-3p inhibitor. Finally, inhibition of circRNA_33702 was shown to attenuate interstitial fibrosis in UUO mice via the miR-29b-3p/WISP1 axis. In general, our data show that circRNA_33702 may promote renal fibrosis via the miR-29b-3p/WISP1 axis, which may potentially be developed as a new therapeutic target. SIGNIFICANCE STATEMENT: This study's findings suggested that circRNA_33702 plays a profibrosis role and that circRNA_33702 with the homologous human hsa_circ_0026331 may be a novel therapeutic target of renal fibrosis.

Emerging Therapeutic Strategies for Attenuating Tubular EMT and Kidney Fibrosis by Targeting Wnt/β-Catenin Signaling

Epithelial-mesenchymal transition (EMT) is defined as a process in which differentiated epithelial cells undergo phenotypic transformation into myofibroblasts capable of producing extracellular matrix, and is generally regarded as an integral part of fibrogenesis after tissue injury. Although there is evidence that the complete EMT of tubular epithelial cells (TECs) is not a major contributor to interstitial myofibroblasts in kidney fibrosis, the partial EMT, a status that damaged TECs remain inside tubules, and co-express both epithelial and mesenchymal markers, has been demonstrated to be a crucial stage for intensifying fibrogenesis in the interstitium. The process of tubular EMT is governed by multiple intracellular pathways, among which Wnt/β-catenin signaling is considered to be essential mainly because it controls the transcriptome associated with EMT, making it a potential therapeutic target against kidney fibrosis. A growing body of data suggest that reducing the hyperactivity of Wnt/β-catenin by natural compounds, specific inhibitors, or manipulation of genes expression attenuates tubular EMT, and interstitial fibrogenesis in the TECs cultured under profibrotic environments and in animal models of kidney fibrosis. These emerging therapeutic strategies in basic researches may provide beneficial ideas for clinical prevention and treatment of chronic kidney disease.

WISP-1 induced by mechanical stress contributes to fibrosis and hypertrophy of the ligamentum flavum through Hedgehog-Gli1 signaling

Ongoing chronic fibrosis and hypertrophy of the ligamentum flavum (LF) is an important cause of lumbar spinal canal stenosis (LSCS). Our previous work showed that WNT1-inducible signaling pathway protein 1 (WISP-1) is a critical driver of LF fibrosis. However, the potential mechanism has not been explored. Here, we found that Gli1 was upregulated in hypertrophic LF tissues and required for fibrogenesis in fibroblasts. Moreover, mechanical stretching increased the expression of WISP-1 in LF fibroblasts. Furthermore, WISP-1 induced fibrogenesis in vitro through the Hedgehog-Gli1 pathway. This conclusion was supported by the fact that WISP-1 activated the Hedgehog-Gli1 pathway in LF fibroblasts and that cyclopamine attenuated the effect of WISP-1-induced fibrogenesis. WISP-1 also promoted the transition of fibroblasts into myofibroblasts via the Hedgehog pathway. Importantly, a hypertrophic LF rabbit model induced by mechanical stress also showed pathological changes in fibrosis and elevated expression of WISP-1, Gli1, and α-SMA. Therapeutic administration of cyclopamine reduced collagen expression, fibroblast proliferation, and myofibroblast differentiation and ameliorated fibrosis in the mechanical stress-induced rabbit model. Collectively, our findings show mechanical stress/WISP-1/Hedgehog signaling as a new fibrotic axis contributing to LF hypertrophy and identify Hedgehog signaling as a therapeutic target for the prevention and treatment of LF fibrosis.

CircRNA_30032 promotes renal fibrosis in UUO model mice via miRNA-96-5p/HBEGF/KRAS axis

In this study, we investigated the role of circular RNA_30032 (circRNA_30032) in renal fibrosis and the underlying mechanisms. The study was carried out using TGF-β1-induced BUMPT cells and unilateral ureteral obstruction (UUO)-induced mice, respectively, as in vitro and in vivo models. CircRNA_30032 expression was significantly increased by 9.15- and 16.6-fold on days 3 and 7, respectively, in the renal tissues of UUO model mice. In TGF-β1-treated BUMPT cells, circRNA_30032 expression was induced by activation of the p38 mitogen-activated protein kinase signaling pathway. Quantitative real-time PCR, western blotting and dual luciferase reporter assays showed that circRNA_30032 mediated TGF-β1-induced and UUO-induced renal fibrosis by sponging miR-96-5p and increasing the expression of profibrotic proteins, including HBEGF, KRAS, collagen I, collagen III and fibronectin. CircRNA_30032 silencing significantly reduced renal fibrosis in UUO model mice by increasing miR-96-5p levels and decreasing levels of HBEGF and KRAS. These results demonstrate that circRNA_30032 promotes renal fibrosis via the miR-96-5p/HBEGF/KRAS axis and suggest that circRNA_30032 is a potential therapeutic target for treatment of renal fibrosis.

Endogenous CCN family member WISP1 inhibits trauma-induced heterotopic ossification

Heterotopic ossification (HO) is defined as abnormal differentiation of local stromal cells of mesenchymal origin, resulting in pathologic cartilage and bone matrix deposition. Cyr61, CTGF, Nov (CCN) family members are matricellular proteins that have diverse regulatory functions on cell proliferation and differentiation, including the regulation of chondrogenesis. However, little is known regarding CCN family member expression or function in HO. Here, a combination of bulk and single-cell RNA sequencing defined the dynamic temporospatial pattern of CCN family member induction within a mouse model of trauma-induced HO. Among CCN family proteins, Wisp1 (also known as Ccn4) was most upregulated during the evolution of HO, and Wisp1 expression corresponded with chondrogenic gene profile. Immunohistochemistry confirmed WISP1 expression across traumatic and genetic HO mouse models as well as in human HO samples. Transgenic Wisp1LacZ/LacZ knockin animals showed an increase in endochondral ossification in HO after trauma. Finally, the transcriptome of Wisp1-null tenocytes revealed enrichment in signaling pathways, such as the STAT3 and PCP signaling pathways, that may explain increased HO in the context of Wisp1 deficiency. In sum, CCN family members, and in particular Wisp1, are spatiotemporally associated with and negatively regulate trauma-induced HO formation.

Prospects and Perspectives for WISP1 (CCN4) in Diabetes Mellitus

The prevalence of diabetes mellitus (DM) continues to increase throughout the world. In the United States (US) alone, approximately ten percent of the population is diagnosed with DM and another thirty-five percent of the population is considered to have prediabetes. Yet, current treatments for DM are limited and can fail to block the progression of multi-organ failure over time. Wnt1 inducible signaling pathway protein 1 (WISP1), also known as CCN4, is a matricellular protein that offers exceptional promise to address underlying disease progression and develop innovative therapies for DM. WISP1 holds an intricate relationship with other primary pathways of metabolism that include protein kinase B (Akt), mechanistic target of rapamycin (mTOR), AMP activated protein kinase (AMPK), silent mating type information regulation 2 homolog 1 (Saccharomyces cerevisiae) (SIRT1), and mammalian forkhead transcription factors (FoxOs). WISP1 is an exciting prospect to foster vascular as well as neuronal cellular protection and regeneration, control cellular senescence, block oxidative stress injury, and maintain glucose homeostasis. However, under some scenarios WISP1 can promote tumorigenesis, lead to obesity progression with adipocyte hyperplasia, foster fibrotic hepatic disease, and lead to dysregulated inflammation with the progression of DM. Given these considerations, it is imperative to further elucidate the complex relationship WISP1 holds with other vital metabolic pathways to successfully develop WISP1 as a clinically effective target for DM and metabolic disorders.

Cleistanthin A inhibits the invasion of MDA-MB-231 human breast cancer cells: involvement of the β-catenin pathway

BACKGROUND

Cleistanthin A (CleA), a natural diphyllin glycoside, has been shown to suppress the invasion of cancer cells, but the underlying mechanisms remain unclear. Here, the inhibitory effect of CleA on the invasion of MDA-MB-231 human breast cancer cells was investigated, and the mechanisms involved were clarified.

METHODS

Cell viability was studied by MTT assay. The migration and invasion of MDA-MB-231 cells were assessed by wound healing assay and transwell assay, respectively. The enzymatic activity of matrix metalloproteinases (MMPs) was detected by gelatin zymography. mRNA and protein levels were detected by qRT-PCR and Western blotting, respectively. Nuclear translocation of β-catenin was observed by immunofluorescence and detected by Western blotting.

RESULTS

CleA effectively inhibited the migration and invasion of MDA-MB-231 cells and suppressed the expression and activation of MMP-2/9. Moreover, the expression and nuclear translocation of β-catenin were reduced by CleA treatment, as well as transcription of the Cyclin D1 and c-myc genes. In addition, the inhibitory effect of CleA on the β-catenin pathway was attributed to the promotion of β-catenin degradation by inhibition of GSK3β phosphorylation. When the phosphorylation of GSK3β was induced by LiCl, the inhibitory effect of CleA on the β-catenin pathway and the invasion of MDA-MB-231 cells were almost reversed.

CONCLUSION

CleA suppressed the invasion of MDA-MB-231 cells, likely through the β-catenin pathway.