The effect of simvastatin and erythropoietin on renal fibrosis in rats with unilateral ureteral obstruction

Regulatory Roles of MicroRNAs in the Pathogenesis of Metabolic Syndrome

Metabolic syndrome refers to a group of several disease conditions together with high glucose triglyceride levels, high blood pressure, lower high-density lipoprotein level, and large waist circumference. About 400 million people worldwide, one-third of the Euro-American population and 27% Chinese population over age 50 have it. microRNAs, an abundant novel class of endogenous small, non-coding RNAs in eukaryotic cells, act as negative controllers of gene expression by promoting either degradation/translational repression of target messenger RNA. More than 2000 microRNAs in the human genome have been identified and they are implicated in various biological & pathophysiological processes, including glucose homeostasis, inflammatory response, and angiogenesis. Destruction of microRNAs has a crucial role in the pathogenesis of obesity, cardiovascular disease, and diabetes. Recently the discovery of circulating microRNAs in human serum may help to promote metabolic crosstalk between organs and serves as a novel approach for the identification of various diseases, like Type 2 diabetes & atherosclerosis. In this review, we will discuss the most recent and up-to-date research on the pathophysiology and histopathology of metabolic syndrome besides their historical background and epidemiological highlight. As well as search the methodologies employed in this field of research and the potential role of microRNAs as novel biomarkers and therapeutic targets for metabolic syndrome in the human body. Furthermore, the significance of microRNAs in promising strategies, like stem cell therapy, which holds enormous promise for regenerative medicine in the treatment of metabolic disorders will also be discussed.

Delayed treatment with erythropoietin attenuates renal fibrosis in mouse model of unilateral ureteral obstruction

OBJECTIVES

Erythropoietin (EPO) exerts tissue-protective effects on various organs including the kidney. However, the effects of EPO on established renal fibrosis remain unclear. In this study, we aimed to examine the therapeutic potential of EPO against established renal fibrosis.

METHODS

Renal fibrosis was induced in mice by unilateral ureteral obstruction (UUO) and the mice were treated with recombinant human EPO (rhEPO) daily during 7 and 13 days after UUO. The degrees of renal fibrosis, myofibroblast accumulation, and macrophage infiltration; the mRNA expression levels of transforming growth factor (TGF)-β1 and α1(I) collagen; and the protein levels of Kelch-like ECH-associated protein 1 (Keap1) and nuclear NF-E2-related factor 2 (Nrf2) in the kidneys were assessed on day 14 after UUO.

RESULTS

Treatment with rhEPO significantly decreased fibrosis, myofibroblast accumulation, and α1(I) collagen mRNA expression, but it did not significantly affect TGF-β1 mRNA expression. Although treatment with rhEPO did not significantly affect the total number of interstitial macrophages, it significantly decreased the number of CD86-positive cells (M1 macrophages), while significantly increased the number of CD206-positive cells (M2 macrophages) in the interstitium. Treatment with rhEPO did not affect the Keap1/Nrf2 protein level or the peripheral blood hematocrit value.

CONCLUSIONS

These results indicate for the first time that EPO exerts antifibrotic effects against the evolution of established renal fibrosis, possibly by influencing the polarization of infiltrating macrophages.

Decreased Imiquimod-Induced Psoriasis-Like Skin Inflammation in a Novel MvdF250S/+ Knock-In Mouse Model

The mevalonate-diphosphate decarboxylase (MVD) gene, a member of the mevalonate pathway, plays a critical role in regulating the biosynthesis of cholesterol, steroid hormones, and non-steroid isoprenoids. Previous studies have suggested that the MVD c.746 T > C mutation is a major pathogenic gene of porokeratosis (PK), an autoinflammatory keratinization disease (AIKD) with unclear pathogenesis, few effective treatments, and no suitable animal model. To investigate the function of Mvd^F250S/+ mutation, we developed a novel Mvd^F250S/+ mouse model carrying an equivalent point mutation to the most common genetic variation among Chinese PK patients (MVD^F249S/+) using CRISPR/Cas9 technology, which exhibited reduced cutaneous expression of Mvd protein. In the absence of external stimulation, Mvd^F250S/+ mice did not display specific phenotypes. However, upon induction with imiquimod (IMQ), Mvd^F250S/+ mice exhibited decreased susceptibility to skin acute inflammation compared to wild-type (WT) mice, as evidenced by reduced cutaneous proliferation and lower protein levels of IL-17a and IL-1β. Additionally, after IMQ induction, the Mvd^F250S/+mice exhibited downregulated collagen generation and upregulated expression of Fabp3 compared to WT mice, whereas no significant changes in the key genes related to cholesterol regulation were found. Furthermore, the Mvd^F250S/+ mutation activated autophagy. Our findings provided insights into the biological function of MVD in the skin.

PPAR γ/TLR4/TGF-β1 axis mediates the protection effect of erythropoietin on cyclosporin A-induced chronic nephropathy in rat

Objective: Nephrotoxicity is the main side effect of cyclosporine A and finding an effective combating method is urgent. The present study investigates the improving effect of erythropoietin (EPO) on cyclosporine A induce renal injury in rats and further explores its possible mechanism.Methods: Recombinant adenovirus for expression of EPO was constructed and injected into kidney with multipoint. Levels of blood urea nitrogen (BUN) and serum creatinine (SCr) were detected by kits. HE staining and Masson's trichrome staining were used to evaluate pathological changes. ELISA was performed to detect the levels of transforming growth factor (TGF)-β1, interleukin (IL)-1β, and IL-6 in serum. Levels of malondialdehyde (MDA) and superoxide dismutase (SOD) in kidney were detected according to manufacturer's instruction. Western blotting was performed to observe the protein expression levels of peroxisome proliferator-activated receptor γ (PPAR γ), Toll-like receptor (TLR) 4, and TGF-β1.Results: Results showed that EPO overexpression in rat kidney could significantly improve renal injury and fibrosis, suppress the release of inflammatory factors and reduce oxidative stress induced by cyclosporine A. Western blotting results showed that EPO overexpression could up-regulate the expression of PPARγ and down-regulate the expression of TLR4 and TGF-β1. Interestingly, when PPARγ activity was inhibited by T0070907, an effective and specific PPARγ inhibitor, the therapeutic effect of EPO was significantly attenuated.Conclusion: Taken together, above results shown the protective effect of EPO on cyclosporine A-induced renal injury and confirmed that EPO's anti-inflammation and antioxidative stress involving the PPAR γ/TLR4/TGFβ1 axis.

Erythropoietin promotes functional recovery via anti-apoptotic mechanisms in mouse unilateral ureteral obstruction

The purpose of the work was to investigate mechanisms of erythropoietin-induced protection and accelerated recovery of kidneys and ureters from obstructive injury. Unilateral ureteral obstruction was established for 24, 48, and 72 h in C57BL/6 mice using a non-traumatic micro-clip followed by the microscopic quantification of ureteral peristalsis pre- and post-obstruction. Expression of erythropoietin, erythropoietin receptor, β-common receptor, and downstream apoptosis-related markers was assessed by RT-PCR and immunohistochemistry in ureters and kidneys and compared to the respective organs on the contralateral side within each animal. Expression of genes in kidneys and ureters from mice treated with 20 IU of erythropoietin daily for 72 h prior to obstruction was compared to that of untreated mice following obstruction. Apoptosis in ureteral tissues after 72-h obstruction was assessed via TUNEL assay. Ureteral obstruction increased apoptosis in affected ureters, with peristaltic function halted following all periods of obstruction. Erythropoietin treatment suppressed apoptosis in obstructed tissues and increased the percentage of mice retaining ureteral function immediately following obstruction reversal. Erythropoietin, erythropoietin receptor, Bcl-2, and Bcl-xl mRNA expression were down-regulated, while phospho-Nf-ĸb p65 was up-regulated in ureteral epithelia following obstruction. Erythropoietin treatment induced anti-apoptotic signaling via down-regulated Bax mRNA expression and abrogated phospho-Nf-ĸb p65. Erythropoietin-induced protection of ureteral function and accelerated recovery post-obstruction removal is mediated via anti-apoptotic mechanisms. Ureteral function is disrupted even following obstruction removal, negatively affecting renal function due to delayed recovery. Thus, our results represent a potential target for the development of safe therapeutic agents aimed at improving functional recovery from obstructive injury.

Carnosic acid protects mice from high-fat diet-induced NAFLD by regulating MARCKS

Non-alcoholic fatty liver disease (NAFLD) comprises a spectrum of liver damage characterized by abnormal hepatic fat accumulation and inflammatory response. Although the molecular mechanisms responsible for the disease are not yet fully understood, the pathogenesis of NAFLD likely involves multiple signals. The identification of effective therapeutic strategies to target these signals is of utmost importance. Carnosic acid (CA), as a phenolic diterpene with anticancer, anti-bacterial, anti-diabetic and neuroprotective properties, is produced by many species of the Lamiaceae family. Myristoylated alanine-rich C-kinase substrate (MARCKS) is a major protein kinase C (PKC) substrate in many different cell types. In the present study, wild-type C57BL/6 and MARCKS-deficient mice were randomly divided into the normal chow- or high-fat (HF) diet-fed groups. The HF diet increased the fasting glucose and insulin levels, and promoted glucose intolerance in the wild-type mice. MARCKS deficiency further upregulated intolerance, fasting glucose and insulin. The HF diet also promoted hepatic steatosis, serum alanine transaminase (ALT) and aspartate transaminase (AST) activity, inflammation and lipid accumulation in the wild-type mice. These responses were accelerated in the MARCKS-deficient mice. Importantly, increased inflammation and lipid accumulation were associated with phosphoinositide 3-kinase (PI3K)/AKT, NLR family pyrin domain containing 3 (NLRP3)/nuclear factor-κB (NF-κB) and sterol regulatory element binding protein-1c (SREBP-1c) signaling pathway activation. The mice treated with CA exhibited a significantly improved glucose and insulin tolerance. The production of pro-inflammatory cytokines and lipid accumulation were suppressed by CA. Significantly, MARCKS was reduced in mice fed the HF diet. CA treatment upregulated MARCKS expression compared to the HF group. Furthermore, the activation of the PI3K/AKT, NLRP3/NF-κB and SREBP-1c signaling pathways was inhibited by CA. Taken together, our data suggest that CA suppresses inflammation and lipogenesis in mice fed a HF diet through MARCKS regulation. Thus, CA may be prove to be a useful anti-NAFLD agent.

Protective effect of hydrogen sulfide on renal injury in the experimental unilateral ureteral obstruction

Introduction/Objective:

Ureteral obstruction is a common pathology and causes kidney fibrosis and dysfunction at late period. In this present study, we investigated the antifibrotic and antiinflammatory effects of hydrogen sulfide on kidney damage after unilateral ureteral obstruction (UUO) in rats.

Materials and Methods:

24 rats were divided into four groups. Group 1 was control, group 2 was sham, group 3 included rats with UUO and group 4 rats with UUO which were given sodium hydrogen sulfide (NaHS)-exogenous donor of hydrogen sulfide (intraperitoneally 56μmoL/kg/day). After 14 days, rats were killed and their kidneys were taken and blood analysis was performed. Tubular necrosis, mononuclear cell infiltration and interstitial fibrosis were determined histopathologically in a part of the kidneys; nitric oxide (NO), malondialdehyde (MDA) and reduced glutathione (GSH) levels were determined in the other part of the kidneys. Urea-creatinine levels were investigated by blood analysis. Statistical analyses were made by the Chi-square test and one-way analysis of variance (ANOVA).

Results:

There was no significantly difference for urea-creatinine levels among groups. Pathologically, there was serious tubular necrosis and fibrosis in group 3 and there was significantly decreasing of tubular necrosis and fibrosis in group 4 (p<0.005). Also, there was significantly increase of NO and MDA levels and decrease of GSH levels in group 3 compared to other groups (p<0.005).

Conclusions:

hydrogen sulfide prevents kidney damage with antioxidant and antiinflammatory effect.

Stereological comparison of the effects of pentoxifylline, captopril, simvastatin, and tamoxifen on kidney and bladder structure after partial urethral obstruction in rats

Purpose

Limited studies have shown antifibrotic effects of pentoxifylline, captopril, simvastatin, and tamoxifen. No comparisons are available of the effects of these drugs on prevention of renal and bladder changes in partial urethral obstruction (PUO).

Materials and Methods

The rats were divided into six groups (n=7). The sham-operated rats (group I) only underwent laparotomy and did not receive any treatments. The PUO groups (group II-VI) received normal saline (PUO+NS), pentoxifylline (100 mg/kg/d; PUO+PEN), captopril (35 mg/kg/d; PUO+CAP), simvastatin (15 mg/kg/d; PUO+SIM), or tamoxifen (10 mg/kg/d; PUO+TAM) by gavage for 28 days. Then, the volume and/or length of the kidney components (tubules, vessels, and fibrous tissue) and the bladder components (epithelial and muscular layers, fibrous tissue, fibroblast and fibrocyte number) were quantitatively evaluated on the microscopic sections by use of stereological techniques.

Results

The volume of renal and bladder fibrosis was significantly ameliorated in the PUO+PEN group, followed by the PUO+CAP, PUO+SIM, and PUO+TAM groups. Also, the volume and length of the renal tubules and vessels and bladder layers were more significantly protected in the PUO+PEN group, followed by the PUO+CAP, PUO+SIM, and PUO+TAM groups.

Conclusions

Treatment of PUO with PEN was more effective in the prevention of renal and bladder fibrosis and in the preservation of renal and bladder structures.

The Role of MicroRNAs in Diabetic Complications-Special Emphasis on Wound Healing

Overweight and obesity are major problems in today’s society, driving the prevalence of diabetes and its related complications. It is important to understand the molecular mechanisms underlying the chronic complications in diabetes in order to develop better therapeutic approaches for these conditions. Some of the most important complications include macrovascular abnormalities, e.g., heart disease and atherosclerosis, and microvascular abnormalities, e.g., retinopathy, nephropathy and neuropathy, in particular diabetic foot ulceration. The highly conserved endogenous small non-coding RNA molecules, the micro RNAs (miRNAs) have in recent years been found to be involved in a number of biological processes, including the pathogenesis of disease. Their main function is to regulate post-transcriptional gene expression by binding to their target messenger RNAs (mRNAs), leading to mRNA degradation, suppression of translation or even gene activation. These molecules are promising therapeutic targets and demonstrate great potential as diagnostic biomarkers for disease. This review aims to describe the most recent findings regarding the important roles of miRNAs in diabetes and its complications, with special attention given to the different phases of diabetic wound healing.

Protective effects of quercetin and hyperoside on renal fibrosis in rats with unilateral ureteral obstruction

Prevention of renal fibrosis is an important therapeutic strategy in the treatment of obstructive nephropathy. The purpose of the present study was to identify whether the combination of two natural plant-derived flavanoids, quercetin and hyperoside (QH), could inhibit renal fibrosis in the model of unilateral ureteral obstruction (UUO) in rats. QH mixtures (1:1) were fed to Wistar rats, and UUO ligation was performed on all the rats with the exception of the sham group. Masson's trichrome staining was used for interstitial fibrosis, while immunohistochemistry and western blot analysis were used to detect the expression of α-smooth muscle actin (SMA) and fibronectin (FN). In the QH group, the expression of SMA and FN was significantly lower than that in the untreated UUO group. In addition, QH administration significantly inhibited the SMA and FN expression of mesangial cells induced by interleukin-1β. Consequently, it was evident that combinational QH therapy prevented UUO-induced renal fibrosis. Based on these findings, the combinatorial intervention of phytomedicine may present an improved treatment strategy for renal fibrotic disease.