Angiotensin-II and rosuvastatin influence matrix remodeling in human mesangial cells via metalloproteinase modulation

Combination of Anti-Angiogenics and Immunotherapies in Renal Cell Carcinoma Show Their Limits: Targeting Fibrosis to Break through the Glass Ceiling?

This review explores treating metastatic clear cell renal cell carcinoma (ccRCC) through current therapeutic modalities-anti-angiogenic therapies and immunotherapies. While these approaches represent the forefront, their limitations and variable patient responses highlight the need to comprehend underlying resistance mechanisms. We specifically investigate the role of fibrosis, prevalent in chronic kidney disease, influencing tumour growth and treatment resistance. Our focus extends to unravelling the intricate interplay between fibrosis, immunotherapy resistance, and the tumour microenvironment for effective therapy development. The analysis centres on connective tissue growth factor (CTGF), revealing its multifaceted role in ccRCC-promoting fibrosis, angiogenesis, and cancer progression. We discuss the potential of targeting CTGF to address the problem of fibrosis in ccRCC. Emphasising the crucial relationship between fibrosis and the immune system in ccRCC, we propose that targeting CTGF holds promise for overcoming obstacles to cancer treatment. However, we recognise that an in-depth understanding of the mechanisms and potential limitations is imperative and, therefore, advocate for further research. This is an essential prerequisite for the successful integration of CTGF-targeted therapies into the clinical landscape.

Distinct Metalloproteinase Expression and Functions in Systemic Sclerosis and Fibrosis: What We Know and the Potential for Intervention

Systemic sclerosis (SSc) is a chronic debilitating idiopathic disorder, characterized by deposition of excessive extracellular matrix (ECM) proteins such as collagen which leads to fibrosis of the skin and other internal organs. During normal tissue repair and remodeling, the accumulation and turnover of ECM proteins are tightly regulated by the interaction of matrix metalloproteinases (MMPs) and endogenous tissue inhibitors of metalloproteinases (TIMPs). SSc is associated with dysregulation of the activity of these proteolytic and inhibitory proteins within the tissue microenvironment, tipping the balance toward fibrosis. The resultant ECM accumulation further perpetuates tissue stiffness and decreased function, contributing to poor clinical outcomes. Understanding the expression and function of these endogenous enzymes and inhibitors within specific tissues is therefore critical to the development of therapies for SSc. This brief review describes recent advances in our understanding of the functions and mechanisms of ECM remodeling by metalloproteinases and their inhibitors in the skin and lungs affected in SSc. It highlights recent progress on potential candidates for intervention and therapeutic approaches for treating SSc fibrosis.

Rosiglitazone attenuates high glucose-induced proliferation, inflammation, oxidative stress and extracellular matrix accumulation in mouse mesangial cells through the Gm26917/miR-185-5p pathway

Rosiglitazone (RSG) is widely used to reduce the amount of sugar in the blood of patients with diabetes mellitus. Diabetic nephropathy is the most common microvascular complication of diabetes. The role of RSG in diabetic nephropathy is not fully understood. Diabetic nephropathy model was constructed in high glucose (HG)-treated mouse mesangial cells. The effects of RSG on cell viability and cell cycle were investigated using cell counting kit-8 (CCK-8) assay and flow cytometry assay. Oxidative stress was assessed according to ROS production and SOD activity in cells. Inflammatory responses were assessed according to the releases of inflammatory cytokines. Extracellular matrix (ECM) accumulation was determined by the levels of fibronectin and collagen IV using western blot. The expression of Gm26917 and microRNA-185-5p (miR-185-5p) was detected by quantitative real-time polymerase chain reaction (qPCR). The interaction between Gm26917 and miR-185-5p was validated by dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay and pull-down assay. RSG significantly inhibited HG-induced proliferation, oxidative stress, inflammatory responses and ECM accumulation in mouse mesangial cells. The expression of Gm26917 was induced by HG but weakened by RSG. Gm26917 knockdown alleviated HG-induced proliferation, oxidative stress, inflammatory responses and ECM accumulation in mouse mesangial cells, and Gm26917 overexpression partly abolished the effects of RSG. Moreover, miR-185-5p was a target of Gm26917, and miR-185-5p inhibition recovered proliferation, oxidative stress, inflammatory responses and ECM accumulation in mouse mesangial cells that were alleviated by Gm26917 knockdown. RSG ameliorated HG-induced mouse mesangial cell proliferation, oxidative stress, inflammation and ECM accumulation partially by governing the Gm26917/miR-185-5p pathway.

Renoprotective effects of tropisetron through regulation of the TGF-β1, p53 and matrix metalloproteinases in streptozotocin-induced diabetic rats

Renal fibrosis is a major cause of renal failure in diabetic nephropathy. Tropisetron is an antagonist of the 5HT3 receptor that exhibits anti-fibrosis effects. The present research aimed to investigate the protected role of tropisetron against renal fibrosis of diabetic nephropathy and its molecular mechanisms. For this purpose, male Wistar rats were allocated into 5 groups of control, tropisetron, diabetes, tropisetron + diabetes, and glibenclamide + diabetes (n = 7). After induction of type 1 diabetes with a single injection of STZ, tropisetron (3 mg/kg) and glibenclamide (1 mg/kg) were given to the rats daily by intraperitoneal injection for 2 weeks. The obtained data revealed that the treatment of diabetic rats with tropisetron led to a significant decrease in the elevated blood glucose, serum cystatin c, and urinary total protein (UTP) level, indicating the improvement of the impaired kidney function. Moreover, the results of Masson's trichrome staining showed that fibrosis attenuated in the kidney of diabetic rats after tropisetron treatment. RT-PCR and Western blotting revealed that TGF-β1, the apoptotic mediator, and p53 were considerably declined in the kidney of diabetic rats in response to tropisetron treatment. Meanwhile, the expressions of matrix metalloproteinase-9 (MMP-9) and matrix metalloproteinase-2 (MMP-2) were increased. These notable effects were equipotent with glibenclamide, as a standard drug, suggesting that tropisetron can alleviate renal fibrosis in diabetic nephropathy. Our data indicate that tropisetron could improve kidney function and attenuate renal fibrosis through regulation of TGF-β1, p53, and expression of extracellular matrix metalloproteinases.

Altered DNA methylation of TRIM13 in diabetic nephropathy suppresses mesangial collagen synthesis by promoting ubiquitination of CHOP

Background

Mesangial collagen synthesis in renal glomeruli contributes to the pathogenesis of diabetic nephropathy (DN) which is one of the most serious complications of diabetes mellitus. However, the underlying mechanism of mesangial collagen synthesis is largely unknown.

Methods

The differential expression of CHOP and TRIM13 which is a well-defined E3 ubiquitin ligase was compared in renal biopsy samples from DN/normal renal tissues, in isolated glomeruli of diabetic/control mice, as well as in high glucose (HG) or TGF-β1-stimulated renal mesangial cells. Then the relationship between TRIM13 and CHOP was explored using the ubiquitination assay.

Findings

We found that the expression of TRIM13 was downregulated in renal biopsies, isolated glomeruli of diabetic mice, and HG/TGF-β1-stimulated renal mesangial cells, while the expression of CHOP was upregulated. An increased level of TRIM13 promoter methylation contributed to the deregulation of TRIM13 in renal glomeruli of DN. The ubiquitination assay confirmed that TRIM13 promoted ubiquitination and degradation of CHOP. Meanwhile, overexpressing TRIM13 attenuated DN-induced collagen synthesis and restored renal function in vitro and in vivo via downregulating CHOP.

Interpretation

Our findings demonstrated that overexpressed TRIM13 suppresses mesangial collagen synthesis in DN by promoting ubiquitination of CHOP, suggesting TRIM13 as a potential therapeutic target in treating DN.

Angiotensin-II induced hypertension and renovascular remodelling in tissue inhibitor of metalloproteinase 2 knockout mice

BACKGROUND

Sustained hypertension induces renovascular remodelling by altering extracellular matrix (ECM) components. Matrix metalloproteinases (MMPs) are Zn-dependent enzymes that regulate ECM turnover in concert with their inhibitors, tissue inhibitors of metalloproteinases (TIMPs). Increased MMP-2 and MMP-9 have been implicated in hypertensive complications; however, the contribution of individual MMPs/TIMPs in renal remodelling has not been fully elucidated. The purpose of this study was to determine the effect of TIMP2 deficiency and thus MMP-2 on angiotensin-II (Ang-II) induced renal remodelling.

METHOD

C57BL/6J (wild-type) and TIMP2 knockout mice were infused with Ang-II at 250 ng/kg per min for 4 weeks. Blood pressure was measured weekly and end-point laser Doppler flowmetry was done to assess cortical blood flow. Immunohistochemical staining was performed for collagen and elastin analyses. The activity of MMP-9 and MMP-2 was determined by Gelatin zymography.

RESULTS

Ang-II induced similar elevation in mean blood pressure in TIMP2 and wild-type mice. In TIMP2 mice, Ang-II treatment was associated with a greater reduction in renal cortical blood flow and barium angiography demonstrated decreased vascular density compared with Ang-II treated wild-type mice. Peri-glomerular and vascular collagen deposition was increased and elastin content was decreased causing increased wall-to-lumen ratio in TIMP2 mice compared with wild-type mice receiving Ang-II. Ang-II increased the expression and activity of MMP-9 predominantly in TIMP2 mice than in wild-type mice.

CONCLUSION

These results suggest that TIMP2 deficiency exacerbates renovascular remodelling in agonist-induced hypertension by a mechanism that may, in part, be attributed to increased activity of MMP-9.

The Notch pathway mediates the angiotensin II-induced synthesis of extracellular matrix components in podocytes

The Notch pathway is known to contribute to the development of glomerular disease. Angiotensin II (Ang II), an important member of the renin-angiotensin system, stimulates the accumulation of extracellular matrix components in glomerular disease; however, the exact mechanisms involved remain to be elucidated. In the present study, we aimed to investigate the effects of the Notch pathway on the synthesis of extracellular matrix components in Ang II-stimulated podocytes. Mouse podocytes were stimulated with Ang II (10-6 mol/l). The activation of the Notch pathway was inhibited by a vector carrying short hairpin RNA (shRNA) targeting Notch1 (sh-Notch1) or by γ-secretase inhibitor (GSI). The protein levels of Notch1, Notch intracellular domain 1 (NICD1), hairy and enhancer of split-1 (Hes1), matrix metalloproteinase (MMP)-2, MMP-9, transforming growth factor-β1 (TGF-β1), type IV collagen and laminin were determined by western blot analysis. The Notch1, Hes1, MMP-2, MMP-9, TGF-β1, type IV collagen and laminin mRNA levels were detected by RT-PCR. The MMP-2 and MMP-9 activity was measured using a cell active fluorescence assay kit. The levels of TGF-β1, type IV collagen and laminin were determined in the culture medium of the podocytes by enzyme-linked immunosorbent assay (ELISA). Our results revealed that Ang II upregulated Notch1, NICD1, Hes1, TGF-β1, type IV collagen and laminin expression and downregulated MMP-2 and MMP-9 expression in the cultured podocytes. The inhibition of the Notch pathway by sh-Notch1 or GSI increased MMP-2 and MMP-9 expression, decreased the TGF-β1 level and suppressed type IV collagen and laminin expression. The inhibition of the Notch pathway by sh-Notch1 or GSI also increased MMP-2 and MMP-9 activity, and decreased TGF-β1 levels, type IV collagen levels and laminin secretion. These findings indicate that the Notch pathway potentially mediates the Ang II-induced synthesis of extracellular matrix components in podocytes through the regulation of MMPs and TGF-β1.

Evaluation of topical application and systemic administration of rosuvastatin in preventing epidural fibrosis in rats

BACKGROUND CONTEXT

Epidural fibrosis is a major challenge in spine surgery, with some patients having recurrent symptoms secondary to excessive formation of scar tissue resulting in neurologic compression. One of the most important factors initiating the epidural fibrosis is assumed to be the transforming growth factor-1β (TGF-1β). Rosuvastatin (ROS) has shown to demonstrate preventive effects over fibrosis via inhibiting the TGF-1β.

PURPOSE

We hypothesized that ROS might have preventive effects over epidural fibrosis through the inhibition of TGF-1β pathways.

STUDY DESIGN

Experimental animal study.

METHODS

Forty-eight adult male Wistar Albino rats were equally and randomly divided into four groups (laminectomy, spongostan, topical ROS, and systemic ROS). Laminectomy was performed at the L3 level in all rats. Four weeks later, the extent of epidural fibrosis was assessed both macroscopically and histopathologically.

RESULTS

Our data revealed that topical application and systemic administration of ROS both were effective in reducing epidural fibrosis formation. Furthermore, the systemic administration of ROS yielded better results than topical application.

CONCLUSIONS

Both topical application and systemic administration of ROS show meaningful preventive effects over epidural fibrosis through multiple mechanisms. The results of our study provide the first experimental evidence of the preventive effects of ROS over epidural fibrosis.

ADAMTS-7 expression increases in the early stage of angiotensin II-induced renal injury in elderly mice

BACKGROUND/AIMS

We investigated the recently described family of proteinases, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTs), and matrix metalloproteinases (MMPs) as inflammatory mediators in inflammatory kidney damage by studying ADAMTS-1, -4, and -7 and MMP-9 expression in elderly mouse kidneys after angiotensin II (Ang II) administration.

METHODS

Ang II (2.5 µg/kg/min) or norepinephrine (8.3 µg/kg/min) was subcutaneously infused in old mice. Renal injury was assessed by hematoxylin-eosin staining, 24-h albuminuria, and immunohistochemistry to evaluate inflammatory cell markers. The mRNA and protein expression of ADAMTS-1, -4, and -7 and MMP-9 were determined using real-time PCR, Western blot, and immunohistochemistry 3 days after Ang II or norepinephrine administration.

RESULTS

Elderly mice in the Ang II group developed hypertension and pathological kidney damage. The mRNA and protein levels of ADAMTS-7 in the Ang II group were 3.3 ± 1.1 (P = 0.019) and 1.6 ± 0.1 (P = 0.047) vs. 1.0 ± 0.1 and 1.0 ± 0.1 in the control group on day 3. In contrast, treatment with the hypertensive agent norepinephrine did not lead to obvious renal damage or an increase in renal ADAMTS-7 expression.

CONCLUSIONS

Renal ADAMTS-7 expression was induced by Ang II in elderly mice. The overexpression of ADATMTS-7 might contribute to early inflammatory kidney damage associated with aging.

Rosuvastatin ameliorates high-fat and high-cholesterol diet-induced nonalcoholic steatohepatitis in rats

BACKGROUND/AIMS

Statins, which are inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase and inhibit endogenous cholesterol synthesis, possess pleiotropic activities, such as anti-inflammatory, anti-oxidative and antifibrotic effects. Here, we investigated whether statins ameliorate steatohepatitis using a high-fat and high-cholesterol (HFHC) diet-induced rat model.

METHODS

Eight-week-old male Sprague-Dawley rats were fed control chow or HFHC diet. Half of the HFHC diet-fed rats were orally administered 2 mg/kg/day rosuvastatin for 12 weeks. Hepatic injury, steatosis, fibrosis and markers of lipid peroxidation/oxidant stress were evaluated.

RESULTS

As previously reported, HFHC diet induced steatohepatitis in rat livers with hypercholesterolaemia. Rosuvastatin decreased Oil Red O stained-positive areas, liver/body weight ratio, serum total cholesterol levels and hepatic free fatty acid contents in HFHC diet-fed rats. Further study revealed that rosuvastatin significantly decreased hepatic mRNA expression of tumour necrosis factor-α and interleukin-6, serum alanine aminotransferase levels and hepatic lobular inflammation grade. Hepatic fibrosis was also ameliorated by rosuvastatin with decreases in hepatic mRNA expression of transforming growth factor-β, connective tissue growth factor and type-1 procollagen. Similarly, hepatic Sirius red stained or α-smooth muscle actin stained-positive areas and expression of markers of lipid peroxidation/oxidant stress [hepatic 8-hydroxy-oxyguanosine and hepatic 4-hydroxy-2-nonenal] were decreased. Interestingly, whereas the expression of carnitine palmitoyltransferase-1 and long-chain acyl-CoA dehydrogenase was not affected, that of catalase and acyl-coA oxidase was restored.

CONCLUSIONS

These data suggest that rosuvastatin improved not only hepatic steatosis but also hepatic injury and fibrosis via improved peroxisomal β-oxidation in this rat HFHC model.

Interaction of RAS activation and lipid disorders accelerates the progression of glomerulosclerosis

BACKGROUND

The activation of the renin-angiotensin system (RAS) and lipid disorders are major risk factors in progressive chronic kidney disease. This study aimed to investigate the potential synergistic mechanisms of RAS activation and lipid disorders that contribute to glomerulosclerosis.

MATERIALS AND METHODS

Human renal mesangial cells (HMCs) were treated with 10(-7) mol/L angiotensin II (Ang II) or with 30 μg/ml cholesterol and 1 μg/ml 25-hydroxycholesterol (lipid loading) for 24 hours. Lipid accumulation in the cells was evaluated by Oil Red O staining and intracellular cholesterol quantitative assays. The gene and protein expression of molecules in the low-density lipoprotein receptor (LDLr) pathway, the RAS family, and the extracellular matrix were examined by real-time polymerase chain reaction and Western blotting. The translocation of sterol regulatory element-binding protein (SREBP) cleavage activating protein (SCAP), which escorts SREBP-2 from the endoplasmic reticulum (ER) to the Golgi, was examined by immunofluorescent staining.

RESULTS

Ang II increased lipid droplet accumulation in HMCs. Further analysis revealed that Ang II increased the mRNA and protein expression of LDLr, SCAP, and SREBP-2. This increase was correlated with an enhanced translocation of the SCAP/SREBP-2 complex from the ER to the Golgi in HMCs that was induced by Ang II, thereby activating LDLr gene transcription. Interestingly, lipid loading increased the mRNA and protein expression of angiotensinogen, Ang II, renin, angiotensin-converting enzyme, angiotensin II type 1 receptor, and type 2 receptor in HMCs with increased mRNA and protein expression of collagen I, α-smooth muscle actin, and fibronectin.

CONCLUSIONS

This study demonstrates that the interaction of RAS activation and lipid disorders accelerates the progression of glomerulosclerosis.