MiR-200a negatively regulates TGF-β1-induced epithelial-mesenchymal transition of peritoneal mesothelial cells by targeting ZEB1/2 expression

MiR-454-3p regulates high glucose-induced mesothelial-mesenchymal transition and glycolysis in peritoneal mesothelial cells by targeting STAT3

BACKGROUND

The quality of life of patients receiving long-term peritoneal dialysis (PD) is significantly impacted by the onset of peritoneal fibrosis (PF), and one of the pathological changes is mesothelial-mesenchymal transition (MMT). In this study, we investigated the potential roles of miR-454-3p and signal transducer and activator of transcription 3 (STAT3) in the progression of peritoneal MMT and the underlying mechanisms.

METHODS

Peritoneums were collected to detect morphology via hematoxylin-eosin staining and differentially expressed miRNAs were detected via RT-qPCR. PD effluent-derived cell populations in the peritoneal cavity were isolated from the effluents of 20 PD patients to determine miR-454-3p, STAT3, and MMT markers via Western blotting and RT-qPCR. The relationship between miR-454-3p and STAT3 was examined via a dual-luciferase reporter assay. Western blotting and RT-qPCR were utilized to evaluate the expression of STAT3, MMT markers, and glycolytic enzymes. Immunofluorescence staining revealed the localization and expression of MMT markers and STAT3.

RESULTS

MiR-454-3p was downregulated in the peritoneums and PD effluent-derived cell populations of long-term PD patients. High glucose (HG) treatment promoted HMrSV5 cell MMT and glycolysis. MiR-454-3p overexpression alleviated HG-induced MMT and suppressed the expression of STAT3 and glycolytic enzymes. In contrast, the miR-454-3p inhibitor exacerbated HG-induced MMT and promoted the expression of glycolytic enzymes and STAT3. Moreover, STAT3 was the target of miR-454-3p.

CONCLUSIONS

This study demonstrated the protective role of miR-454-3p in HG-induced MMT and glycolysis in HMrSv5 cells, suggesting that miR-454-3p may prevent MMT by suppressing glycolytic enzymes via the STAT3/PFKFB3 pathway in the HG environment.

Peritoneal fibrosis: from pathophysiological mechanism to medicine

Peritoneal dialysis (PD) is currently one of the effective methods for treating end-stage renal disease (ESRD). However, long-term exposure to high concentration glucose in peritoneal dialysis environment could lead to peritoneal fibrosis (PF), impaired peritoneal filtration function, decreased peritoneal dialysis efficiency, and even withdrawal from peritoneal dialysis in patients. Considerable evidence suggests that peritoneal fibrosis after peritoneal dialysis is related to crucial factors such as mesothelial-to-mesenchymal transition (MMT), inflammatory response, and angiogenesis, etc. In our review, we summarize the pathophysiological mechanisms and further illustrate the future strategies against PF.

MiR-150-5p Alleviates Renal Tubule Epithelial Cell Fibrosis via the Inhibition of Epithelial-Mesenchymal Transition by Targeting ZEB1

INTRODUCTION

Although microRNA (miR)-150-5p participates in the progression of renal fibrosis, its mechanism of action remains elusive.

METHODS

A mouse model of unilateral ureteral obstruction was used. The in vitro renal fibrosis model was established by stimulating human kidney 2 (HK-2) cells with transforming growth factor beta 1 (TGF-β1). The expression profiles of miR-150-5p, zinc finger E-box binding homeobox 1 (ZEB1), and other fibrosis- and epithelial-mesenchymal transition (EMT)-linked proteins were determined using Western blot and quantitative reverse transcription polymerase chain reaction. The relationship between miR-150-5p and ZEB1 in HK-2 cells was confirmed by a dual-luciferase reporter assay.

RESULTS

Both in vivo and in vitro renal fibrosis models revealed reduced miR-150-5p expression and elevated ZEB1 level. A significant decrease in E-cadherin levels, as well as increases in alpha smooth muscle actin (α-SMA) and collagen type I (Col-I) levels, was seen in TGF-β1-treated HK-2 cells. The overexpression of miR-150-5p ameliorated TGF-β1-mediated fibrosis and EMT. Notably, miR-150-5p acts by directly targeting ZEB1. A significant reversal of the inhibitory impact of miR-150-5p on TGF-β1-mediated fibrosis and EMT in HK-2 cells was observed upon ZEB1 overexpression.

CONCLUSION

MiR-150-5p suppresses TGF-β1-induced fibrosis and EMT by targeting ZEB1 in HK-2 cells, providing helpful insights into the therapeutic intervention of renal fibrosis.

Resveratrol inhibits arecoline-induced fibrotic properties of buccal mucosal fibroblasts via miR-200a activation

Background/purpose

Oral submucous fibrosis (OSF) is a precancerous lesion in the oral cavity, commonly results from the Areca nut chewing habit. Arecoline, the main component of Areca nut, is known to stimulate the activation of myofibroblasts, which can lead to abnormal collagen I deposition. Meanwhile, Resveratrol is a non-flavonoid phenolic substance that can be naturally obtained from various berries and foods. Given that resveratrol has significant anti-fibrosis traits in other organs, but little is known about its effect on OSF, this study aimed to investigate the therapeutic impact of resveratrol on OSF and its underlying mechanism.

Materials and methods

The cytotoxicity of resveratrol was tested using normal buccal mucosal fibroblasts (BMFs). Myofibroblast phenotypes such as collagen contractile, enhanced migration, and wound healing capacities in dose-dependently resveratrol-treated fBMFs were examined.

Results

Current results showed that arecoline induced cell migration and contractile activity in BMFs as well as upregulated the expressions of α-SMA, type I collagen, and ZEB1 markers. Resveratrol intervention, on the other hand, was shown to inhibit arecoline-induced myofibroblast activation and reduce myofibroblast hallmarks and EMT markers. Additionally, resveratrol was also demonstrated to restore the downregulated miR-200a in the arecoline-stimulated cells.

Conclusion

In a nutshell, these findings implicate that resveratrol may have an inhibitory influence on arecoline-induced fibrosis via the regulation of miR-200a. Hence, resveratrol may be used as a therapeutic strategy for OSF intervention.

Unleashing the pathological imprinting of cancer in autoimmunity: Is ZEB1 the answer?

The intriguing scientific relationship between autoimmunity and cancer immunology have been traditionally indulged to throw spotlight on novel pathological targets. Understandably, these "slowly killing" diseases are on the opposite ends of the immune spectrum. However, the immune regulatory mechanisms between autoimmunity and cancer are not always contradictory and sometimes mirror each other based on disease stage, location, and timepoint. Moreover, the blockade of immune checkpoint molecules or signalling pathways that unleashes the immune response against cancer is being leveraged to preserve self-tolerance and treat many autoimmune disorders. Therefore, understanding the common crucial factors involved in cancer is of paramount importance to paint the autoimmune disease spectrum and validate novel drug candidates. In the current review, we will broadly describe how ZEB1, or Zinc-finger E-box Binding Homeobox 1, reinforces immune exhaustion in cancer or contributes to loss of self-tolerance in auto-immune conditions. We made an effort to exchange information about the molecular pathways and pathological responses (immune regulation, cell proliferation, senescence, autophagy, hypoxia, and circadian rhythm) that can be regulated by ZEB1 in the context of autoimmunity. This will help untwine the intricate and closely postured pathogenesis of ZEB1, that is less explored from the perspective of autoimmunity than its counterpart, cancer. This review will further consider several approaches for targeting ZEB1 in autoimmunity.

The Progress of Platelets in Breast Cancer

Breast cancer is the most common female cancer and the sixth leading cause of death, seriously affecting the quality of life of women. Platelets, one of the fragments derived from megakaryocytes, are being increasingly investigated by tumor researchers because of their anticoagulant function. According to relevant studies, platelets, as the key source of circulating angiogenesis-related factors, can regulate tumor angiogenesis and vascular integrity, and they can also affect the tumor microenvironment, thereby facilitating the proliferation and differentiation of tumor cells. By covering or transferring normal MHC I molecules to tumor cells, platelets can protect tumor cells from being killed by the immune system and facilitate tumor cell metastasis. However, details on the mechanisms involved have remained elusive. This paper reviews and analyzes studies of the role of platelets in tumorigenesis, tumor cell proliferation, tumor metastasis, and cancer treatment to provide readers with a better understanding of the relevant studies.

Mechanisms of Peritoneal Mesothelial Cells in Peritoneal Adhesion

A peritoneal adhesion (PA) is a fibrotic tissue connecting the abdominal or visceral organs to the peritoneum. The formation of PAs can induce a variety of clinical diseases. However, there is currently no effective strategy for the prevention and treatment of PAs. Damage to peritoneal mesothelial cells (PMCs) is believed to cause PAs by promoting inflammation, fibrin deposition, and fibrosis formation. In the early stages of PA formation, PMCs undergo mesothelial–mesenchymal transition and have the ability to produce an extracellular matrix. The PMCs may transdifferentiate into myofibroblasts and accelerate the formation of PAs. Therefore, the aim of this review was to understand the mechanism of action of PMCs in PAs, and to offer a theoretical foundation for the treatment and prevention of PAs.

LncRNA GAS5 Competitively Combined With miR-21 Regulates PTEN and Influences EMT of Peritoneal Mesothelial Cells via Wnt/β-Catenin Signaling Pathway

Objective

Epithelial-mesenchymal transition (EMT) is an important factor leading to peritoneal fibrosis (PF) in end-stage renal disease (ESRD) patients. The current research aimed to evaluate the effect of long non-coding RNA growth arrest-specific 5 (lncRNA GAS5) in human peritoneal mesothelial cells (HPMCs) EMT and explore the potential molecular mechanisms.

Materials and Methods

HPMCs were cultured under control conditions or with high glucose (HG). The cells were then treated with lncRNA GAS5, lncRNA GAS5 siRNA, with or without miR-21 inhibitor and PTEN transfection. Expression of lncRNA GAS5, miR-21, α-SMA, Vimentin, E-cadherin, phosphatase and tensin homolog deleted on chromosome ten (PTEN), Wnt3a, and β-catenin were measured by real time PCR and Western blotting. Bioinformatics analyses were used to test the specific binding sites between the 3' UTR of the PTEN gene, miR-21, and lncRNA GAS5. Rescue experiments were performed to confirm the lncRNA GAS5/miR-21/PTEN axis in HPMC EMT.

Results

We found that HG-induced EMT decreased lncRNA GAS5 and that overexpression of lncRNA GAS5 can attenuate EMT in HPMCs. In addition, lncRNA GAS5 regulated HG-induced EMT through miR-21/PTEN. Cotransfection of miR-21 inhibitors remarkably increased PTEN expression and attenuated EMT in lncRNA GAS5 knockdown HPMCs. Moreover, rescue experiments showed that overexpression of PTEN attenuated the EMT effects of lncRNA GAS5 siRNA in HPMCs. We also confirmed that the Wnt/β-catenin pathway was stimulated in lncRNA GAS5/miR-21/PTEN-mediated EMT.

Conclusion

Our research showed that lncRNA GAS5 competitively combined with miR-21 to regulate PTEN expression and influence EMT of HPMCs via the Wnt/β-catenin signaling pathway. This study provides novel evidence that lncRNA GAS5 may be a potential therapeutic target for HPMC EMT.

Noncoding RNAs in peritoneal fibrosis: Background, Mechanism, and Therapeutic Approach

Peritoneal fibrosis (PF) is the main reason for patients to withdraw from peritoneal dialysis, while the mechanism underlying PF remains unclear. Increasing evidence has demonstrated the regulatory roles of different classes of noncoding RNAs (ncRNAs) in PF. MicroRNAs (miRNAs), which belong to a distinct class of ncRNAs, play crucial roles in the post-transcriptional regulation of gene expression. Studies have suggested that miRNAs play important roles in the pathogenesis of PF and have the potential to be used as diagnostic markers and therapeutic targets for PF in the future. Long noncoding RNAs (lncRNAs) have raised much attention in the recent years, which are involved in the pathophysiological processes of many diseases, including tumors, heart diseases and so on. Recently, some researchers have begun to notice the roles of lncRNAs in PF, and found that lncRNAs play certain roles in the pathogenesis of PF. Circular RNAs (circRNAs) have been proven to be participated in the pathogenesis of many diseases, including tumor metastasis, organ fibrosis and so on. However, studies on the correlation of circRNAs and PF are rather poor compared with miRNAs and lncRNAs. In this review, we will focus on the findings of ncRNAs in peritoneal dialysis therapy and discuss the rising interests in ncRNAs as diagnostic and therapeutic targets of PF.

Radix Angelica Sinensis and Radix Hedysari Ultrafiltration Extract Protects against X-Irradiation-Induced Cardiac Fibrosis in Rats

Radiation-induced myocardial fibrosis (RIMF) is the main pathological change associated with radiation-induced heart toxicity after radiation therapy in patients with thoracic tumors. There is an antifibrosis effect of Radix Angelica Sinensis and Radix Hedysari (RAS-RH) ultrafiltration extract from Danggui Buxue decoction (DBD) in X-irradiation-induced rat myocardial fibrosis, and this study aimed to investigate whether that effect correlated with apoptosis and oxidative stress damage in primary rat cardiac fibroblasts; further, the potential mechanisms were also explored. In this study, we first found that the RAS-RH antifibrosis effect was associated with the upregulation of microRNA-200a and the downregulation of TGF-β1/smad3 and COL1α. In addition, we also found that the antifibrosis effect of RAS-RH was related to the induction of apoptosis in primary rat cardiac fibroblasts and to the prevention of damage caused by reactive oxygen species (ROS). Interestingly, primary rat cardiac fibroblasts exposed to X-ray radiation underwent apoptosis less frequently in the absence of RAS-RH. Therefore, RAS-RH has the ability to protect against fibrosis, which could be occurring through the induction of apoptosis and the resistance to oxidative stress in rats with X-irradiation-induced myocardial fibrosis; thus, in a model of RIMF, RAS-RH acts against X-irradiation-induced cardiac toxicity.

Nitro-oleic acid inhibits the high glucose-induced epithelial-mesenchymal transition in peritoneal mesothelial cells and attenuates peritoneal fibrosis

As an electrophilic nitroalkene fatty acid, nitro-oleic acid (OA-NO₂) exerts multiple biological effects that contribute to anti-inflammation, anti-oxidative stress, and antiapoptosis. However, little is known about the role of OA-NO₂ in peritoneal fibrosis. Thus, in the present study, we examined the effects of OA-NO₂ on the high glucose (HG)-induced epithelial-mesenchymal transition (EMT) in human peritoneal mesothelial cells (HPMCs) and evaluated the morphological and immunohistochemical changes in a rat model of peritoneal dialysis-related peritoneal fibrosis. In in vitro experiments, we found that HG reduced the expression level of E-cadherin and increased Snail, N-cadherin, and α-smooth muscle actin expression levels in HPMCs. The above-mentioned changes were attenuated by pretreatment with OA-NO₂. Additionally, OA-NO₂ also inhibited HG-induced activation of the transforming growth factor-β₁/Smad signaling pathway and NF-κB signaling pathway. Meanwhile, OA-NO₂ inhibited HG-induced phosphorylation of Erk and JNK. The results from the in vivo experiments showed that OA-NO₂ notably relieved peritoneal fibrosis by decreasing the thickness of the peritoneum; it also inhibited expression of transforming growth factor-β₁, α-smooth muscle actin, N-cadherin, and vimentin and enhanced expression of E-cadherin in the peritoneum. Collectively, these results suggest that OA-NO₂ inhibits the HG-induced epithelial-mesenchymal transition in HPMCs and attenuates peritoneal dialysis-related peritoneal fibrosis.

Small molecule inhibitors of epithelial-mesenchymal transition for the treatment of cancer and fibrosis

Tissue fibrosis and cancer both lead to high morbidity and mortality worldwide; thus, effective therapeutic strategies are urgently needed. Because drug resistance has been widely reported in fibrotic tissue and cancer, developing a strategy to discover novel targets for targeted drug intervention is necessary for the effective treatment of fibrosis and cancer. Although many factors lead to fibrosis and cancer, pathophysiological analysis has demonstrated that tissue fibrosis and cancer share a common process of epithelial-mesenchymal transition (EMT). EMT is associated with many mediators, including transcription factors (Snail, zinc-finger E-box-binding protein and signal transducer and activator of transcription 3), signaling pathways (transforming growth factor-β1, RAC-α serine/threonine-protein kinase, Wnt, nuclear factor-kappa B, peroxisome proliferator-activated receptor, Notch, and RAS), RNA-binding proteins (ESRP1 and ESRP2) and microRNAs. Therefore, drugs targeting EMT may be a promising therapy against both fibrosis and tumors. A large number of compounds that are synthesized or derived from natural products and their derivatives suppress the EMT by targeting these mediators in fibrosis and cancer. By targeting EMT, these compounds exhibited anticancer effects in multiple cancer types, and some of them also showed antifibrotic effects. Therefore, drugs targeting EMT not only have both antifibrotic and anticancer effects but also exert effective therapeutic effects on multiorgan fibrosis and cancer, which provides effective therapy against fibrosis and cancer. Taken together, the results highlighted in this review provide new concepts for discovering new antifibrotic and antitumor drugs.

miR-200c Prevents TGF-β1-Induced Epithelial-to-Mesenchymal Transition and Fibrogenesis in Mesothelial Cells by Targeting ZEB2 and Notch1

Peritoneal fibrosis and loss of transport function is a common complication contributing to adverse outcomes in patients on long-term peritoneal dialysis (PD). Epithelial-to-mesenchymal transition (EMT) in mesothelial cells is a salient feature, but its triggering mechanisms remain obscure. Dysregulation of microRNA (miR) expression is implicated in EMT and tissue fibrosis. We investigated the role of miR-200c in EMT and fibrogenesis in a murine PD model and in cultured peritoneal mesothelial cells. PD-fluid-treated mice showed peritoneal miR-200c expression reduced by 76.2% compared with PBS-treated mice, and this was accompanied by increased peritoneal α-smooth muscle actin, fibronectin, and collagen expression. PD fluid and TGF-β1 both reduced miR-200c expression in cultured mesothelial cells, accompanied by downregulation of E-cadherin and decorin, and induction of fibronectin, collagen I and III, and transcription factors related to EMT. Decorin prevented the suppression of miR-200c by TGF-β1. Lentivirus-mediated miR-200c overexpression prevented the induction of fibronectin, collagen I, and collagen III by TGF-β1, independent of decorin, and partially prevented E-cadherin suppression by TGF-β1. Target genes of miR-200c were identified as ZEB2 and Notch1. Our data demonstrate that miR-200c regulates EMT and fibrogenesis in mesothelial cells, and loss of peritoneal miR-200c contributes to PD-associated peritoneal fibrosis.

MiR-200a ameliorates peritoneal fibrosis and functional deterioration in a rat model of peritoneal dialysis

Peritoneal fibrosis is recognised as the main cause of the technical failure of peritoneal dialysis (PD), and currently, there are no specific and effective anti-fibrosis therapies. We have found that miR-200a is down-regulated in a rat model of PD-related peritoneal fibrosis (PF) and could inhibit transforming growth factor beta 1 (TGF-β1)-induced epithelial-mesenchymal transition (EMT) in peritoneal mesothelial cells by target ZEB1/2. However, its treatment role in vivo is still largely unclear. In this study, we examined the therapeutic potential for miR-200a on PD-related PF in a rat model of PD induced by daily infusion of 4.25% dextrose-containing dialysate. Male Sprague-Dawley rats were divided into four groups: control group, PD group, PD + miR-agomir-NC group, and PD + miR-200a-agomir group (n = 5 in each group). MiR-200a agomir was delivered into the peritoneum by intra-peritoneal injection on days 10 and 20 after PD. We found that treatment with miR-200a agomir significantly reduced the collagen volume fraction (CVF) of the peritoneum and prevented peritoneal dysfunction. The up-regulation of the EMT marker (decreased E-cadherin and increased α-smooth muscle actin) and extracellular matrix (fibronectin and collagen I) was significantly ameliorated by miR-200a in the PD + miR-200a-agomir group. Furthermore, we demonstrated that miR-200a inhibition of PF in vivo was associated with the suppression of ZEB1 and 2, which were proved to be the target of miR-200a in our previous study. In conclusion, results from the present study suggest that treatment with miR-200a may represent a novel and effective therapy for PD-related PF.

Osthole Ameliorates Renal Fibrosis in Mice by Suppressing Fibroblast Activation and Epithelial-Mesenchymal Transition

Renal fibrosis is a common pathway of virtually all progressive kidney diseases. Osthole (OST, 7-Methoxy-8-(3-methylbut-2-enyl)-2-chromenone), a derivative of coumarin mainly found in plants of the Apiaceae family, has shown inhibitory effects on inflammation, oxidative stress, fibrosis and tumor progression. The present study investigated whether OST mediates its effect via suppressing fibroblast activation and epithelial-mesenchymal transition (EMT) in unilateral ureteral obstruction (UUO)-induced renal fibrosis in mice. Herein, we found that OST inhibited fibroblast activation in a dose-dependent manner by inhibiting the transforming growth factor-β1 (TGFβ1)-Smad pathway. OST also blocked fibroblast proliferation by reducing DNA synthesis and downregulating the expressions of proliferation- and cell cycle-related proteins including proliferating cell nuclear antigen (PCNA), CyclinD1 and p21 Waf1/Cip1. Meanwhile, in the murine model of renal interstitial fibrosis induced by UUO, myofibroblast activation with increased expression of α-smooth muscle actin (α-SMA) and proliferation were attenuated by OST treatment. Additionally, we provided in vivo evidence suggesting that OST repressed EMT with preserved E-cadherin and reduced Vimentin expression in obstructed kidney. UUO injury-induced upregulation of EMT-related transcription factors, Snail family transcriptional repressor-1(Snail 1) and Twist family basic helix-loop-helix (BHLH) transcription factor (Twist) as well as elevated G2/M arrest of tubular epithelial cell, were rescued by OST treatment. Further, OST treatment reversed aberrant expression of TGFβ1-Smad signaling pathway, increased level of proinflammatory cytokines and NF-kappaB (NF-κB) activation in kidneys with obstructive nephropathy. Taken together, these findings suggest that OST hinder renal fibrosis in UUO mouse mainly through inhibition of fibroblast activation and EMT.