Transforming growth factor-beta and Smad signalling in kidney diseases

Nebivolol ameliorates sepsis-evoked kidney dysfunction by targeting oxidative stress and TGF-β/Smad/p53 pathway

Sepsis is a potential fetal organ destruction brought on through an overzealous immunologic reaction to infection, causing severe inflammation, septic shock, and damage to different organs. Although there has been progress in the identification and controlling of clinical sepsis, the fatality rates are still significant. This study, for the first time, intended to examine the possible ameliorative impact of Nebivolol, a β1-adrenergic antagonist antihypertensive drug, against nephrotoxicity resulted from cecal ligation and puncture (CLP)-induced sepsis in rats, on molecular basis. Sixty male Wistar albino rats were chosen. Oxidative stress indicators and biochemical markers of kidney activity were evaluated. Inflammatory mediators, fibrosis- and apoptosis-related proteins and gene expressions were investigated. Moreover, renal histopathological investigation was performed. CLP-induced nephrotoxicity characterized by markedly elevated serum levels of creatinine, blood urea nitrogen, uric acid, and renal malondialdhyde. On the other hand, it decreased serum total protein level, renal superoxide dismutase activity and reduced glutathione level. Additionally, it significantly elevated the renal inflammatory mediators (tumor necrosis factor-alpha, ilnerlukin (IL)-6, and IL-1β) and Caspase-3 protein, reduced IL-10 level, amplified the expression of transforming growth factor-beta 1 (TGF-β1), p-Smad2/3 and alpha-smooth-muscle actin proteins, downregulated the B cell lymphoma-2 (Bcl-2) gene and elevated the transcription of Bcl-2-associated X-protein (Bax), p53 and Nuclear factor-kappa B (NF-κB) genes. Furtheremor, kidney tissues exhibited significant histopathological changes with CLP. On the contrary, Nebivolol significantly improved all these biochemical changes and enhanced the histopathological alterations obtained by CLP. This research showed, for the first time, that Nebivolol effectively mitigated the CLP-induced kidney dysfunction via its antioxidant, antifibrotic and anti-apoptotic activity through modulation of oxidative stress, TGF-β/NF-κB and TGF-β/Smad/p53 signaling pathways.

The SGLT2 inhibitor empagliflozin inhibits skeletal muscle fibrosis in naturally aging male mice through the AMPKα/MMP9/TGF-β1/Smad pathway

ABSTACT

With advancing age, the incidence of sarcopenia increases, eventually leading to a cascade of adverse events. However, there is currently a lack of effective pharmacological treatment for sarcopenia. Sodium-glucose co-transporter 2 inhibitor (SGLT2i) empagliflozin demonstrates anti-fibrotic capabilities in various organs. This study aims to determine whether empagliflozin can improve skeletal muscle fibrosis induced by sarcopenia in naturally aging mice. A natural aging model was established by feeding male mice from 13 months of age to 19 months of age. A fibrosis model was created by stimulating skeletal muscle fibroblasts with TGF-β1. The Forelimb grip strength test assessed skeletal muscle function, and expression levels of COL1A1, COL3A1, and α-SMA were analyzed by western blot, qPCR, and immunohistochemistry. Additionally, levels of AMPKα/MMP9/TGFβ1/Smad signaling pathways were examined. In naturally aging mice, skeletal muscle function declines, expression of muscle fibrosis markers increases, AMPKα expression is downregulated, and MMP9/TGFβ1/Smad signaling pathways are upregulated. However, treatment with empagliflozin reverses this phenomenon. At the cellular level, empagliflozin exhibits similar anti-fibrotic effects, and these effects are attenuated by Compound C and siAMPKα. Empagliflozin exhibits anti-fibrotic effects, possibly associated with the AMPK/MMP9/TGFβ1/Smad signaling pathways.

Cartilage regeneration using transforming growth factor-beta 3-loaded injectable crosslinked hyaluronic acid hydrogel

Cartilage defects can be difficult to heal, potentially leading to complications such as osteoarthritis. Recently, a tissue engineering approach that uses scaffolds and growth factors has been proposed to regenerate new cartilage tissues. Herein, we investigated the application of hyaluronic acid (HA) gel loaded with transforming growth factor-beta 3 (TGF-β3) for enhanced cartilage regeneration. We assessed the clinical conditions required to efficiently enhance the ability of the modified HA gel to repair defective cartilage. Based on our findings, the prepared HA gel exhibited good physicochemical and mechanical properties and was non-toxic and non-inflammatory. Moreover, HA gel-loaded TGF-β3 (HAT) had improved biocompatibility and promoted the synthesis of cartilage-specific matrix and collagen, further improving its ability to repair defects. The application of HAT resulted in an initial burst release of HA, which degraded slowly in vivo. Finally, HAT combined with microfracture-inducing bone marrow stem cells could significantly improve the cartilage microenvironment and regeneration of cartilage defects. Our results indicate that HA is a suitable material for developing growth factor carriers, whereas HAT is a promising candidate for cartilage regeneration. Furthermore, this differentiated strategy provides a rapid and effective clinical approach for next-generation cartilage regeneration.

Natural products in traditional Chinese medicine: molecular mechanisms and therapeutic targets of renal fibrosis and state-of-the-art drug delivery systems

Renal fibrosis (RF) is the end stage of several chronic kidney diseases. Its series of changes include excessive accumulation of extracellular matrix, epithelial-mesenchymal transition (EMT) of renal tubular cells, fibroblast activation, immune cell infiltration, and renal cell apoptosis. RF can eventually lead to renal dysfunction or even renal failure. A large body of evidence suggests that natural products in traditional Chinese medicine (TCM) have great potential for treating RF. In this article, we first describe the recent advances in RF treatment by several natural products and clarify their mechanisms of action. They can ameliorate the RF disease phenotype, which includes apoptosis, endoplasmic reticulum stress, and EMT, by affecting relevant signaling pathways and molecular targets, thereby delaying or reversing fibrosis. We also present the roles of nanodrug delivery systems, which have been explored to address the drawback of low oral bioavailability of natural products. This may provide new ideas for using natural products for RF treatment. Finally, we provide new insights into the clinical prospects of herbal natural products.

Omeprazole induces profibrotic gene expression in rat kidney: implication of TGF-β/Smad signaling pathway

Proton pump inhibitors (PPIs) are one of the most commonly prescribed medications. However, PPI usage is linked to a higher risk of both acute and chronic renal damage by mechanisms not entirely known. The present study demonstrates that omeprazole (10 mg/kg body weight, i.p.) causes TGF-β/Smad signaling activation and subsequent expression of the profibrotic genes CTGF and TIMP-1 in rat kidney. Increased production of CTGF and TIMP-1 accompany activation of the TGF-β/Smad signaling cascade. However, simultaneous treatment of omeprazole and the TGF-β inhibitor, disitertide (P144) (1 mg/kg body weight i.p.) suppresses the TGF-β/Smad signaling pathway and subsequent production of CTGF and TIMP-1. Additionally, TGF-β level in rat kidney was highly reduced in animals treated with the ROS (reactive oxygen species) scavenger, N-acetyl cysteine (NAC) (100 mg/kg body weight i.p.) before omeprazole administration. Furthermore, the reduction in SOD activity brought by omeprazole was returned to the normal level in those animals. However, MDA level increased by omeprazole was highly reduced in the presence of NAC. Collectively, the current findings demonstrate that omeprazole has the ability to promote the expression of the profibrotic genes CTGF and TIMP-1 in a ROS and TGF-β dependent manner. The present study suggests the co-use of ROS scavenger to improve the therapeutic use of the PPI omeprazole.

Precision Medicine in Erythropoietin Deficiency and Treatment Resistance: A Novel Approach to Management of Anaemia in Chronic Kidney Disease

The study of anaemia is a well-developed discipline where the concepts of precision medicine have, in part, been researched extensively. This review discusses the treatment of erythropoietin (EPO) deficiency anaemia and resistance in cases of chronic kidney disease (CKD). Traditionally, erythropoietin-stimulating agents (ESAs) and iron supplementation have been used to manage anaemia in cases of CKD. However, these treatments pose potential risks, including cardiovascular and thromboembolic events. Newer treatments have emerged to address these risks, such as slow-release and low-dosage intravenous iron, oral iron supplementation, and erythropoietin-iron combination therapy. Another novel approach is the use of hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs). This review highlights the need for precision medicine targeting the genetic components of EPO deficiency anaemia in CKD and discusses individual variability in genes such as the erythropoietin gene (EPO), the interleukin-β gene (IL-β), and the hypoxia-inducible factor gene (HIF). Pharmacogenetic testing aims to provide targeted therapies and interventions that are tailored to the specific characteristics of an individual, thus optimising treatment outcomes and minimising resistance and adverse effects. This article concludes by suggesting that receptor modification has the potential to revolutionise the treatment outcomes of patients with erythropoietin deficiency anaemia through the integration of the mentioned approach.

Apolipoprotein A-I attenuates peritoneal fibrosis associated with peritoneal dialysis by inhibiting oxidative stress and inflammation

Apolipoprotein A-I (apoA-I), 90% of which is present in high-density lipoprotein (HDL), is the main constituent of HDL, has anti-inflammatory and anti-oxidant properties, and has received extensive attention in anti-atherosclerosis. Yet little is known about apoA-I 's role in peritoneal dialysis. In this study, by analyzing PD patients (n = 81), we found that decreased apoA/HDL-C ratio is significantly associated with rapid decline in peritoneal function. Further studies were performed in animal experiments to determine the ascendancy of apolipoprotein A-I mimetic peptide (D-4F) on peritoneum, we found that D-4F administration reduced peritoneal fibrosis and peritoneal endothelial mesenchymal transformation (EMT) induced by high glucose peritoneal dialysate, such as N-cadherin, Fibronectin, Vimentin, and α-smooth muscle actin (α-SMA) expression decreased. In mechanism, D-4F can significantly inhibit Smad2/3 phosphorylation, which is the major pathway leading to fibrosis. Furthermore, D-4F treatment inhibited NADPH oxidase and thiobarbituric acid reactive substances (TBARS) expression, increased the activity of certain enzymes, such as superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Finally, treatment with D-4F inhibits the expression of interleukins-6(IL-6), Interleukin-1β(IL-1β), and tumor necrosis factor-α(TNF-α). Taken together, based on the above research evidence, apoA-I and its peptide mimic may regulate the oxidative stress, TGF- β1/Smads signaling pathway and inflammatory response to reduce peritoneal fibrosis due to peritoneal dialysis.

Tenascins and osteopontin in biological response in cornea

The structural composition, integrity and regular curvature of the cornea contribute to the maintenance of its transparency and vision. Disruption of its integrity caused by injury results in scarring, inflammation and neovascularization followed by losses in transparency. These sight compromising effects is caused by dysfunctional corneal resident cell responses induced by the wound healing process. Upregulation of growth factors/cytokines and neuropeptides affect development of aberrant behavior. These factors trigger keratocytes to first transform into activated fibroblasts and then to myofibroblasts. Myofibroblasts express extracellular matrix components for tissue repair and contract the tissue to facilitate wound closure. Proper remodeling following primary repair is critical for restoration of transparency and visual function. Extracellular matrix components contributing to the healing process are divided into two groups; a group of classical tissue structural components and matrix macromolecules that modulate cell behaviors/activities besides being integrated into the matrix structure. The latter components are designated as matricellular proteins. Their functionality is elicited through mechanisms which modulate the scaffold integrity, cell behaviors, activation/inactivation of either growth factors or cytoplasmic signaling regulation. We discuss here the functional roles of matricellular proteins in mediating injury-induced corneal tissue repair. The roles are described of major matricellular proteins, which include tenascin C, tenascin X and osteopontin. Focus is directed towards dealing with their roles in modulating individual activities of wound healing-related growth factors, e. g., transforming growth factor β (TGF β). Modulation of matricellular protein functions could encompass a potential novel strategy to improve the outcome of injury-induced corneal wound healing.

Exploration of potential mechanism of Rougan formula against hepatic fibrosis by network analysis and experimental assessment

ETHNOPHARMACOLOGICAL RELEVANCE

Rougan Formula (RG) has long been clinically applied to treat hepatic fibrosis in patients with different chronic liver diseases. However, the core active substances and the potential pharmacological mechanisms of RG remain unclear.

AIM OF THE STUDY

The purpose of this study is to explore bioactive components, key targets, and potential mechanisms of RG by performing network pharmacological analyses and experimental model validation.

MATERIALS AND METHODS

All chemical components in RG extract were identified using ultraperformance liquid chromatography-quadrupole/time-of-flight tandem mass technology. The candidate components and drug targets of RG, as well as disease-related genes, were extracted from TCMSP and GeneCards databases. The potential pathways related to genes were predicted by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses. The core bioactive components, key targets, and signaling pathways were ultimately obtained by analyzing protein-protein interaction (PPI) and component-target-pathway (C-T-P) networks. Subsequently, the efficacy and underlying mechanisms of RG on hepatic fibrosis were experimentally validated in transforming growth factor-beta 1 (TGF-β1)-induced hepatic stellate cell activation model and CCL₄-induced hepatic fibrosis mouse model.

RESULTS

A total of 52 components in RG extract were obtained, and 22 of them were selected as the core bioactive components. Five hundred and thirty-nine overlapped targets were determined by matching drug targets with disease-related targets. The results of PPI and C-T-P network analyses revealed 100 key targets and 19 signaling pathways associated with RG efficacy. In vitro and in vivo studies further verified that RG exerted a significant anti-hepatic fibrotic effect by suppressing the activation of hepatic stellate cells by downregulating the TGF-β1/Smads signaling pathway.

CONCLUSIONS

These results may provide some evidence for further clinical research and development of RG formula as an effective and safe drug for hepatic fibrosis treatment.

Gastrodin attenuates renal injury and collagen deposition via suppression of the TGF-β1/Smad2/3 signaling pathway based on network pharmacology analysis

Background: Gastrodin has been widely used clinically in China as an antihypertensive drug. However, its effect on hypertensive renal injury is yet to be elucidated. The current study aimed to investigate the effects of gastrodin on hypertensive renal injury and its underlying mechanisms by network pharmacology analysis and validation in vivo and in vitro. Methods: A total of 10 spontaneously hypertensive rats (SHRs) were randomly categorized into the following two groups: SHR and SHR + Gastrodin groups. Wistar Kyoto (WKY) rats were used as the control group (n = 5). The SHR + Gastrodin group was intragastrically administered gastrodin (3.5 mg/kg/day), and the rats in both WKY and SHR groups were intragastrically administered an equal amount of double-distilled water for 10 weeks. Hematoxylin-eosin, Masson's trichrome, and Sirius red staining were used to detect the pathological changes and collagen content in the renal tissues. Network pharmacology analysis was performed to explore its potential targets and related pathways. In vitro, the CCK-8 assay was used to determine the cell viability. Immunohistochemistry and western-blotting analyses were employed to assess the protein expression associated with renal fibrosis and transforming growth factor-β1 (TGF-β1) pathway-related proteins in the renal tissues or in TGF-β1-stimulated rat kidney fibroblast cell lines (NRK-49F). Results: Gastrodin treatment attenuates renal injury and pathological alterations in SHRs, including glomerular sclerosis and atrophy, epithelial cell atrophy, and tubular dilation. Gastrodin also reduced the accumulation of collagen in the renal tissues of SHRs, which were confirmed by downregulation of α-SMA, collagen I, collagen III protein expression. Network pharmacology analysis identified TGFB1 and SMAD2 as two of lead candidate targets of gastrodin on against hypertensive renal injury. Consistently, gastrodin treatment downregulated the increase of the protein expression of TGF-β1, and ratios of both p-Smad2/Smad2 and p-Samd3/Smad3 in renal tissues of SHRs. In vitro, gastrodin (25-100 μM) treatment significantly reversed the upregulation of α-SMA, fibronectin, collagen I, as well as p-Smad2 and p-Smad3 protein expressions without affecting the cell viability of TGF-β1 stimulated NRK-49F cells. Conclusion: Gastrodin treatment significantly attenuates hypertensive renal injury and renal fibrosis and suppresses TGF-β1/Smad2/3 signaling in vivo and in vitro.

Blood TGF-β1 and miRNA-21-5p levels predict renal fibrosis and outcome in IgA nephropathy

BACKGROUND

IgA nephropathy (IgAN), the most common primary glomerulonephritis, often presents as advanced renal failure with end-stage renal disease at diagnosis. Tubulointerstitial injury and fibrosis on histology are the most important predictors of renal outcome. A non-invasive biomarker is required for assessment of progression in IgA nephropathy. We investigated the utility of blood profibrotic molecules, TGF-β1 and miRNA-21-5p (miR-21), to identify a non-invasive biomarker for renal fibrosis in IgAN.

MATERIALS AND METHODS

The study included 30 IgAN (mean age 31.5 ± 9 years) at the time of initial diagnosis, 25 age-sex-matched healthy controls and 10 Lupus nephritis patients as disease controls. Serum TGF-β1 was analyzed by enzyme-linked immunosorbent assay and plasma miR-21 by qRT-PCR, normalized with U6-snRNA. The levels were correlated with clinical features, laboratory parameters, histological Oxford MEST-C score and renal outcome.

RESULTS

The serum TGF-β1 and plasma miR-21 were significantly higher in patients with IgAN than in healthy controls. TGF-β1 significantly correlated with serum creatinine, eGFR, Oxford T score and miR-21. High plasma miR-21 was significantly associated with T score and interstitial inflammation. On multivariate analysis, high levels of TGF-β1 and miR-21 correlated with lower eGFR and T score, respectively. On a follow-up period of 21.5 months, high miR-21 expression at diagnosis was associated (p = 0.02) with a poor renal outcome having a shorter time to doubling of serum creatinine.

CONCLUSION

High blood TGF-β1 and miR-21 expression at diagnosis of IgAN show significant correlation with renal function and degree of chronic tubulointerstitial injury on histology.

The miR-103a-3p/TGFBR3 axis regulates TGF-β-induced orbital fibroblast activation and fibrosis in thyroid-eye disease

Molecular pathways that contribute to orbital fibroblast activation during thyroid-eye disease (TED) may promote TED progression. Non-coding RNAs, especially miRNAs, play a critical role in the pathogenesis of TED. In the present study, miR-103a-3p was dramatically upregulated and TGFBR3 was downregulated within TED orbital tissue samples and TGF-β-stimulated TED orbital fibroblasts. miR-103a-3p inhibition in TGF-β-stimulated TED orbital fibroblasts partially abolished TGF-β-induced fibrotic alterations, as manifested by the impaired fibroblast cell viability and decreased vimentin and fibronectin levels. miR-103a-3p directly targeted TGFBR3 in TED orbital samples and TGF-β-stimulated TED orbital fibroblasts. In TGF-β-stimulated TED orbital fibroblasts, TGFBR3 overexpression inhibited fibroblast cell viability and decreased vimentin and fibronectin levels. TGFBR3 overexpression partially attenuated the inhibitory effects of miR-103a-3p overexpression on TGFBR3 expression and the promotive effects of miR-103a-3p overexpression on TGF-β-induced fibrotic alterations. Under TGF-β stimulation, miR-103a-3p overexpression significantly promoted, whereas TGFBR3 overexpression inhibited the phosphorylation of Erk1/2, JNK, Smad2, and Smad3. TGFBR3 overexpression also partially abolished the effects of miR-103a-3p overexpression on Erk1/2, JNK, Smad2, and Smad3 phosphorylation. In conclusion, the miR-103a-3p/TGFBR3 axis regulated TGF-β-induced TED orbital fibroblast activation and fibrosis in TED, with the possible involvement of the Erk/JNK and TGF-β/Smad signaling pathways.

An In-Silico Identification of Potential Flavonoids against Kidney Fibrosis Targeting TGFβR-1

Fibrosis is a hallmark of progressive kidney diseases. The overexpression of profibrotic cytokine, namely transforming growth factor β (TGF-β) due to excessive inflammation and tissue damage, induces kidney fibrosis. The inhibition of TGF-β signaling is markedly limited in experimental disease models. Targeting TGF-β signaling, therefore, offers a prospective strategy for the management of kidney fibrosis. Presently, the marketed drugs have numerous side effects, but plant-derived compounds are relatively safer and more cost-effective. In this study, TGFβR-1 was targeted to identify the lead compounds among flavonoids using various computational approaches, such as ADME/T (absorption, distribution, metabolism, and excretion/toxicity) analysis, molecular docking, and molecular dynamics simulation. ADME/T screening identified a total of 31 flavonoids with drug-like properties of 31 compounds, a total of 5 compounds showed a higher binding affinity to TGFβR-1, with Epicatechin, Fisetin, and Luteolin ranking at the top three (-13.58, -13.17, and -10.50 kcal/mol, respectively), which are comparable to the control drug linagliptin (-9.074 kcal/mol). The compounds also exhibited outstanding protein-ligand interactions. The molecular dynamic simulations revealed a stable interaction of these compounds with the binding site of TGFβR-1. These findings indicate that flavonoids, particularly Epicatechin, Fisetin, and Luteolin, may compete with the ligand-binding site of TGFβR-1, suggesting that these compounds can be further evaluated for the development of potential therapeutics against kidney fibrosis. Further, in-vitro and in-vivo studies are recommended to support the current findings.

Influence of myrcene on inflammation, matrix accumulation in the kidney tissues of streptozotocin-induced diabetic rat

There is only limited literature studies on the activities of inflammation and matrix accumulation in the renal tissues of rats induced with diabetes through Streptozotocin. The present the investigation involves the examination of the protective actions of Myrcene (MYN), a monoterpene on the oxidative stress, inflammation, and matrix accumulation. For this purpose an experimental setup was created which involves injecting MYN 50 mg/kg for about 45 days in the STZ diabetic rats. Modifications in the enzymes, collagens, growth factor B₁ and Kappa factor P65 were identified and tracked. The levels of the inflammatory markers like TF-α1, ICAM-1, VCAM-1, MCP-1 were tracked and noted. The current experimental results showed an alteration in the glucose metabolism and enhanced condition. Also an increased level of TGF-β-1 and Nuclear factor-kB expression was seen in the renal tissues. MYN was found to reduce glucose oxidative stress and exhibit an anti-inflammatory effect via inhibiting NF-kB signalling. The conclusion of the current study reveals that MYN regulates the inflammatory activities and matrix accumulation by inhibiting the activities of inflammatory cytokine, pro-inflammatory signalling.

Redox signaling pathways in unilateral ureteral obstruction (UUO)-induced renal fibrosis

Unilateral ureteral obstruction (UUO) is an experimental rodent model that mimics renal fibrosis associated with obstructive nephropathy in an accelerated manner. After UUO, the activation of the renin-angiotensin system (RAS), nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOXs) and mitochondrial dysfunction lead to reactive oxygen species (ROS) overproduction in the kidney. ROS are secondary messengers able to induce post-translational modifications (PTMs) in redox-sensitive proteins, which activate or deactivate signaling pathways. Therefore, in UUO, it has been proposed that ROS overproduction causes changes in said pathways promoting inflammation, oxidative stress, and apoptosis that contribute to fibrosis development. Furthermore, mitochondrial metabolism impairment has been associated with UUO, contributing to renal damage in this model. Although ROS production and oxidative stress have been studied in UUO, the development of renal fibrosis associated with redox signaling pathways has not been addressed. This review focuses on the current information about the activation and deactivation of signaling pathways sensitive to a redox state and their effect on mitochondrial metabolism in the fibrosis development in the UUO model.

In Vitro and In Vivo Study on the Toxic Effects of Propiconazole Fungicide in the Pathogenesis of Liver Fibrosis

Propiconazole (PCZ) is a hepatotoxic triazole fungicide. There are insufficient data on how PCZ induces liver fibrosis in humans. This study aimed to investigate the effect of PCZ on liver fibrosis and its underlying mechanisms. HepG2 cells and Sprague-Dawley rats were exposed to PCZ at doses of 0-160 μM (3-72 h) and 0.5-50 mg/kg body weight/day (28 days), respectively. PCZ-treated cells activated intracellular oxidative stress via cytochrome P450 and had higher mRNA levels of interleukin-1β, tumor necrosis factor-α, matrix metalloproteinase (MMP)-2, MMP-9, and transforming growth factor-β (TGF-β) than the control. PCZ treatment in cells induced a morphological transition with E-cadherin decrease and vimentin and Snail increase via the oxidative stress and TGF-β/Smad pathways. PCZ administration in rats induced liver fibrosis through pathological changes, epithelial-mesenchymal transition, and collagen deposition. Thus, our data suggest that exposure of PCZ to humans may be a risk factor for the functional integrity of the liver.

Discovery and biological evaluation of phthalazines as novel non-kinase TGFβ pathway inhibitors

TGFβ is crucial for the homeostasis of epithelial and neural tissues, wound repair, and regulating immune responses. Its dysregulation is associated with a vast number of diseases, of which modifying the tumor microenvironment is one of vital clinical interest. Despite various attempts, there is still no FDA-approved therapy to inhibit the TGFβ pathway. Major mainstream approaches involve impairment of the TGFβ pathway via inhibition of the TGFβRI kinase. With the purpose to identify non-receptor kinase-based inhibitors to impair TGFβ signaling, an in-house chemical library was enriched, through a computational study, to eliminate TGFβRI kinase activity. Selected compounds were screened against a cell line engineered with a firefly luciferase gene under TGFβ-Smad-dependent transcriptional control. Results indicated moderate potency for a molecule with phthalazine core against TGFβ-Smad signaling. A series of phthalazine compounds were synthesized and evaluated for potency. The most promising compound (10p) exhibited an IC₅₀ of 0.11 ± 0.02 μM and was confirmed to be non-cytotoxic up to 12 μM, with a selectivity index of approximately 112-fold. Simultaneously, 10p was confirmed to reduce the Smad phosphorylation using Western blot without exhibiting inhibition on the TGFβRI enzyme. This study identified a novel small-molecule scaffold that targets the TGFβ pathway via a non-receptor-kinase mechanism.

Nanomedicine in the treatment of diabetic nephropathy

Globally, diabetic nephropathy (DN) is the foremost cause of end-stage renal disease. With the incidence of diabetes increasing day by day, DN's occurrence is expected to surge to pandemic proportions. Current available therapeutic interventions associated with DN emphasize blood pressure, glycemia and lipid control while ignoring DN's progression mechanism at a molecular level. This review sheds light on the molecular insights involved in DN to help understand the initiation and progression pattern. Further, we summarize novel strategies with reported applications in developing a nanomedicine-based platform for DN-targeted drug delivery to improve drug efficacy and safety.

Expression and clinical significance of paired- related homeobox 1 and Smad2 in gastric cancer

BACKGROUND

China has a high incidence rate and low survival rate of gastric cancer. Therefore, there is a great need to further identify novel oncogenes and clinically applicable molecular targets for the diagnosis and treatment of this disease.

METHODS

Expressions of PRRX1, Smad2, epithelial phenotype marker E-cadherin, and interstitial phenotype vimentin protein in a sample of 64 gastric carcinoma and adjacent nontumorous tissues were detected by immunohistochemistry. Their relationship and correlations with clinicopathological features were analyzed.

RESULTS

The positive rates of PRRX1, Smad2, E-cadherin, and vimentin protein in primary tumors were 60.94% (39/64), 59.38% (38/64), 34.38%(22/64), and 64.06% (41/64), respectively. A significant correlation was found among the expression of PRRX1, Smad2, E-cadherin, and vimentin (P < 0.05). Expression of the PRRX1, Smad2, and vimentin protein in gastric cancer tissue was correlated with Borrmann classification, lymph node-positive number, the degree of differentiation, depth of tumor invasion, and serum pepsinogen I (PGI) level (P < 0.05), but not with age, sex, serum carcinoembryonic antigen, serum CA199, or PGI/PGII (P > 0.05).

CONCLUSION

The positive rate of PRRX1 protein expression was positively correlated with the protein expression of Smad2 and vimentin, but negatively correlated with E-cadherin protein. PRRX1, Smad2, and vimentin proteins are associated with Borrmann type, lymph node positives, histologic grade, depth of tumor invasion, and serum PGI levels, all of which contribute to a poor prognosis for patients with gastric cancer.

Heightened Crescentic Glomerulonephritis in Immune Challenged 129sv Mice Is TGF-β/Smad3 Dependent

The 129sv mouse strain is particularly sensitive to experimental immune-mediated nephritis. Previous studies have indicated that transforming growth factor-β (TGF-β) plays a critical role in both immune modulation and tissue fibrogenesis in various diseases and that its biological activities are exerted via the SMAD family. In this study, we aimed to determine whether TGF-β/SMAD signaling is essential for the development of immune-mediated nephritis in 129sv mice. Relative to C57BL/6J control mice with anti-glomeruli basement membrane (GBM) nephritis, 129sv mice with anti-GBM nephritis exhibited increased renal collagen deposition. Additionally, higher mRNA levels of pro-collagen and collagen IV, higher serum levels of active and total TGF-β1, and increased TGF-β1, TGF-βIIR, and phosphorylated SMAD expression were detected in these mice. Deletion of Smad3 in 129sv mice ameliorated anti-GBM induced nephritis, including crescentic glomerulonephritis. Collectively, these findings indicate that the heightened experimental nephritis and fibrotic disease in the 129sv strain of mice are regulated by SMAD3, which could be a potential therapeutic target for immune-mediated nephritis.

Metformin Attenuates Renal Fibrosis in a Mouse Model of Adenine-Induced Renal Injury Through Inhibiting TGF-β1 Signaling Pathways

It is well-known that all progressive chronic kidney disease (CKD) is pathologically characterized by tubulointerstitial fibrosis process. Multiple studies have shown the critical role of inflammation and fibrosis in the development of CKD. Hence strategies that target inflammatory and fibrotic signaling pathways may provide promising opportunities to protect against renal fibrosis. Metformin has been used as the first-line glucose-lowering agent to treat patients with type 2 diabetes mellitus (T2DM) for over 50 years. Accumulating evidence suggests the potential for additional therapeutic applications of metformin, including mitigation of renal fibrosis. In this study, the anti-fibrotic effects of metformin independent of its glucose-lowering mechanism were examined in an adenine -induced mouse model of CKD. Expressions of inflammatory markers MCP-1, F4/80 and ICAM, fibrotic markers type IV collagen and fibronectin, and the cytokine TGF-β1 were increased in adenine-induced CKD when compared to control groups and significantly attenuated by metformin treatment. Moreover, treatment with metformin inhibited the phosphorylation of Smad3, ERK1/2, and P38 and was associated with activation of the AMP-activated protein kinase (AMPK) in the kidneys of adenine-treated mice. These results indicate that metformin attenuates adenine-induced renal fibrosis through inhibition of TGF-β1 signaling pathways and activation of AMPK, independent of its glucose-lowering action.

The role of miR-29 family in disease

MicroRNAs are small noncoding RNAs that can bind to the target sites in the 3’‐untranslated region of messenger RNA to regulate posttranscriptional gene expression. Increasing evidence has identified the miR‐29 family, consisting of miR‐29a, miR‐29b‐1, miR‐29b‐2, and miR‐29c, as key regulators of a number of biological processes. Moreover, their abnormal expression contributes to the etiology of numerous diseases. In the current review, we aimed to summarize the differential expression patterns and functional roles of the miR‐29 family in the etiology of diseases including osteoarthritis, osteoporosis, cardiorenal, and immune disease. Furthermore, we highlight the therapeutic potential of targeting members of miR‐29 family in these diseases. We present miR‐29s as promoters of osteoblast differentiation and apoptosis but suppressors of chondrogenic and osteoclast differentiation, fibrosis, and T cell differentiation, with clear avenues for therapeutic manipulation. Further research will be crucial to identify the precise mechanism of miR‐29 family in these diseases and their full potential in therapeutics.

Enhanced asthma-related fibroblast to myofibroblast transition is the result of profibrotic TGF-β/Smad2/3 pathway intensification and antifibrotic TGF-β/Smad1/5/(8)9 pathway impairment

Airway remodelling with subepithelial fibrosis, which abolishes the physiological functions of the bronchial wall, is a major issue in bronchial asthma. Human bronchial fibroblasts (HBFs) derived from patients diagnosed with asthma display in vitro predestination towards TGF-β₁-induced fibroblast-to-myofibroblast transition (FMT), a key event in subepithelial fibrosis. As commonly used anti-asthmatic drugs do not reverse the structural changes of the airways, and the molecular mechanism of enhanced asthma-related TGF-β₁-induced FMT is poorly understood, we investigated the balance between the profibrotic TGF-β/Smad2/3 and the antifibrotic TGF-β/Smad1/5/9 signalling pathways and its role in the myofibroblast formation of HBF populations derived from asthmatic and non-asthmatic donors. Our findings showed for the first time that TGF-β-induced activation of the profibrotic Smad2/3 signalling pathway was enhanced, but the activation of the antifibrotic Smad1/5/(8)9 pathway by TGF-β₁ was significantly diminished in fibroblasts from asthmatic donors compared to those from their healthy counterparts. The impairment of the antifibrotic TGF-β/Smad1/5/(8)9 pathway in HBFs derived from asthmatic donors was correlated with enhanced FMT. Furthermore, we showed that Smad1 silencing in HBFs from non-asthmatic donors increased the FMT potential in these cells. Additionally, we demonstrated that activation of antifibrotic Smad signalling via BMP7 or isoliquiritigenin [a small-molecule activator of the TGF-β/Smad1/5/(8)9 pathway] administration prevents FMT in HBFs from asthmatic donors through downregulation of profibrotic genes, e.g., α-SMA and fibronectin. Our data suggest that influencing the balance between the antifibrotic and profibrotic TGF-β/Smad signalling pathways using BMP7-mimetic compounds presents an unprecedented opportunity to inhibit subepithelial fibrosis during airway remodelling in asthma.

Microparticles derived from human erythropoietin mRNA-transfected mesenchymal stem cells inhibit epithelial-to-mesenchymal transition and ameliorate renal interstitial fibrosis

Background

Renal tubulointerstitial fibrosis (TIF) plays an important role in the progression of chronic kidney disease (CKD) and its pathogenesis involves epithelial-to-mesenchymal transition (EMT) upon renal injury. Recombinant human erythropoietin (rhEPO) has been shown to display novel cytoprotective effects, in part by inhibiting transforming growth factor (TGF)-β1-induced EMT. Here, we evaluated the inhibitory effects of microparticles (MPs) derived from human EPO gene-transfected kidney mesenchymal stem cells (hEPO-KMSCs) against TGF-β1-induced EMT in Madin-Darby canine kidney (MDCK) cells and against TIF in mouse kidneys with unilateral ureteral obstruction (UUO).

Methods

EMT was induced in MDCK cells by treatment with TGF-β1 (5 ng/mL) for 48 h and then inhibited by co-treatment with rhEPO (100 IU/mL), mock gene-transfected KMSC-derived MPs (MOCK-MPs), or hEPO-KMSC-derived MPs (hEPO-MPs) for a further 48 h. UUO was induced in FVB/N mice, which were then treated with rhEPO (1000 IU/kg, intraperitoneally, every other day for 1 week), MOCK-MPs, or hEPO-MPs (80 μg, intravenously). Alpha-smooth muscle actin (α-SMA), fibronectin, and E-cadherin expression were evaluated in MDCK cells and kidney tissues, and the extent of TIF in UUO kidneys was assessed by immunohistochemical staining.

Results

TGF-β1 treatment significantly increased α-SMA and fibronectin expression in MDCK cells and decreased that of E-cadherin, while co-treatment with rhEPO, MOCK-MPs, or hEPO-MPs markedly attenuated these changes. In addition, rhEPO and hEPO-MP treatment effectively decreased phosphorylated Smad2 and Smad3, as well as phosphorylated p38 mitogen-activated protein kinase (MAPK) expression, suggesting that rhEPO and rhEPO-MPs can inhibit TGF-β1-induced EMT via both Smad and non-Smad pathways. rhEPO and hEPO-MP treatment also significantly attenuated the extent of renal TIF after 1 week of UUO compared to MOCK-MPs, with hEPO-MPs significantly reducing myofibroblast and F4/80+ macrophage infiltration as well as EMT marker expression in UUO renal tissues in a similar manner to rhEPO.

Conclusions

Our results demonstrate that hEPO-MPs modulate TGF-β1-induced EMT in MDCK cells via the Smad2, Smad3, and p38 MAPK pathways and significantly attenuated renal TIF in UUO kidneys.

The efficacy of taking traditional Chinese medicine orally in renal interstitial fibrosis: A protocol for a systematic review and meta-analysis

BACKGROUND

By now, the incidence of chronic kidney disease (CKD) is increasing. The development of various CKD is attributed to the continuous aggravation of renal interstitial fibrosis (RIF) in the process of end-stage renal disease (ESRD). Oral treatment of traditional Chinese medicine (TCM) is one of the therapies for RIF. Randomized controlled trials (RCTs) of TCM treatment RIF have been reported, but its effectiveness and safety have yet been systematically investigated. Therefore, through the systematic analysis and meta-analysis, our study will summarize the effectiveness and safety of oral treatment RIF of TCM, in order to provides scientific reference for clinical practice.

METHODS

This protocol follows Preferred Reporting Items for Systematic Evaluation and Meta-Analysis. RCTs will be only selected. Such databases as the PubMed, China National Knowledge Infrastructure (CNKI), China Science and Technology Journal Database (VIP), Excerpt Medical Database (Embase), WanFan Data, Chinese Biomedical Literature Database (CBM), WHO International Clinical Trials Registry Platform will be searched from the inception to June, 2020 to collect the RCTs about taking TCM orally in treating RIF. The literature according to the inclusion and exclusion criteria, data-extracted and the methodological quality evaluated will be performed independently by 2 reviewers. The clinical outcomes including renal function indices (Scr, BUN, 24-hour urinary protein quantity) and Indicators of RIF (TGF-β1, Notch1, Jagged-1). The risk of bias included in the RCTs will be evaluated by the bias risk assessment tool provided in the Cochrane System Evaluation Manual 5.1.0. Review Manager 5.3 provided by the Cochrane collaboration network will be used to process the data.

RESULTS AND CONCLUSION

Some more targeted and practical results about the efficacy of taking TCM orally in RIF have been provided by our study. The available evidence suggests that the therapeutic effects of combining TCM with Western medicine therapies is much better for RIF than Western medicine therapies only.

Effect of functional variant rs11466313 on breast cancer susceptibility and TGFB1 promoter activity

PURPOSE

This study aimed to investigate whether genetic polymorphisms in TGFB1 contribute to breast cancer (BC) susceptibility, and explore the mechanism of action.

METHODS

A total of 7 tagging SNPs (tSNPs) were genotyped in 1161 BC cases and 1337 age-matched controls among Chinese Han population. Bioinformatics analysis was used to predict functional SNP closely linked to tSNPs. Luciferase gene reporter assay was performed to determine the effect of genetic variants on promoter activity. DNA pull-down assay and mass spectrometry were used to identify the differentially binding proteins to genetic variants.

RESULTS

Genotyping analysis showed that rs1800469 (C>T) in the 5' regulatory region of TGFB1 was associated with reduced BC risk. Bioinformatics analysis predicted that rs11466313 (-2389_-2391 Del/AGG) in the 5' regulatory region of TGFB1, was closely linked to tSNP rs1800469 and could be functional. The genotyping of rs11466313 by PCR-SSCP showed that rs11466313 also conferred decreased BC risk. Luciferase assays demonstrated that rs11466313 minor allele reduced over ninefold of promoter activity compared with its major allele (p < 0.001). DNA pull-down assay and mass spectrometry revealed that rs11466313 minor allele lost the binding ability with FAM98B and HSP90B. Knocking down FAM98B but not HSP90B, the enhanced promoter activity driven by TGFB1 rs11466313 major allele was attenuated.

CONCLUSIONS

This study elucidates the impact of functional polymorphism rs11466313 in the regulatory region of TGFB1 on breast cancer susceptibility and gene expression, and could be helpful for future research to determine the value of this TGFB1 variant in the clinical setting.

RIPK3: A New Player in Renal Fibrosis

Chronic kidney disease (CKD) is the end result of a plethora of renal insults, including repeated episodes of acute or toxic kidney injury, glomerular, or diabetic kidney disease. It affects a large number of the population worldwide, resulting in significant personal morbidity and mortality and economic cost to the community. Hence it is appropriate to focus on treatment strategies that interrupt the development of kidney fibrosis, the end result of all forms of CKD, in addition to upstream factors that may be specific to certain diseases. However, the current clinical approach to prevent or manage renal fibrosis remains unsatisfactory. The rising importance of receptor-interacting serine/threonine-protein kinase (RIPK) 3 in the inflammatory response and TGF-β1 signaling is increasingly recognized. We discuss here the biological functions of RIPK3 and its role in the development of renal fibrosis.

Oleanolic Acid Attenuates Renal Fibrosis through TGF-β/Smad Pathway in a Rat Model of Unilateral Ureteral Obstruction

Renal fibrosis is a common final pathological process in the progression of kidney disease. Oleanolic acid is a bioactive pentacyclic triterpenoid and is widely found in medicinal herbs around the world. In this study, we explored the effect of oleanolic acid on renal fibrosis and the underlying molecular mechanisms by using a rat model of unilateral ureteral obstruction (UUO). Male Sprague-Dawley rats were orally administered with oleanolic acid (6 mg/kg/d) or vehicle (olive oil) for 21 days after the UUO surgery. Upon termination, urine and blood were collected for renal function analysis, and kidneys were harvested for pathological analysis by using hematoxylin-eosin and Masson trichrome staining. Changes of extracellular matrix mRNA expressions and TGF-β/Smad signaling in the kidneys were also determined. As a result, oleanolic acid significantly reduced the kidney index, the level of serum creatinine and blood urea nitrogen, and the urinary level of microalbumin, α1-microglobulin, and N-acetyl-β-glucosaminidase. Masson trichrome staining showed significantly less collagen deposition in the UUO rats with oleanolic acid treatment. Diminished mRNA expressions of collagen I, collagen III, fibronectin, and α-SMA in the kidney tissues were observed after the treatment. Oleanolic acid led to decreased protein expressions of TGF-β, TGF-β receptor I, and TGF-β receptor II, as well as the phosphorylation of Smad2. Our current study suggested that oleanolic acid could be a complementary and alternative therapy for renal fibrosis potentially by targeting the TGF-β/Smad pathway.

Diverse Role of TGF-β in Kidney Disease

Inflammation and fibrosis are two pathological features of chronic kidney disease (CKD). Transforming growth factor-β (TGF-β) has been long considered as a key mediator of renal fibrosis. In addition, TGF-β also acts as a potent anti-inflammatory cytokine that negatively regulates renal inflammation. Thus, blockade of TGF-β inhibits renal fibrosis while promoting inflammation, revealing a diverse role for TGF-β in CKD. It is now well documented that TGF-β1 activates its downstream signaling molecules such as Smad3 and Smad3-dependent non-coding RNAs to transcriptionally and differentially regulate renal inflammation and fibrosis, which is negatively regulated by Smad7. Therefore, treatments by rebalancing Smad3/Smad7 signaling or by specifically targeting Smad3-dependent non-coding RNAs that regulate renal fibrosis or inflammation could be a better therapeutic approach. In this review, the paradoxical functions and underlying mechanisms by which TGF-β1 regulates in renal inflammation and fibrosis are discussed and novel therapeutic strategies for kidney disease by targeting downstream TGF-β/Smad signaling and transcriptomes are highlighted.

Potential targeted therapy and diagnosis based on novel insight into growth factors, receptors, and downstream effectors in acute kidney injury and acute kidney injury-chronic kidney disease progression

Acute kidney injury (AKI) is defined as a rapid decline in renal function and is characterized by excessive renal inflammation and programmed death of resident cells. AKI shows high morbidity and mortality, and severe or repeated AKI can transition to chronic kidney disease (CKD) or even end-stage renal disease (ESRD); however, very few effective and specific therapies are available, except for supportive treatment. Growth factors, such as epidermal growth factor (EGF), insulin-like growth factor (IGF), and transforming growth factor-β (TGF-β), are significantly altered in AKI models and have been suggested to play critical roles in the repair process of AKI because of their roles in cell regeneration and renal repair. In recent years, a series of studies have shown evidence that growth factors, receptors, and downstream effectors may be highly involved in the mechanism of AKI and may function in the early stage of AKI in response to stimuli by regulating inflammation and programmed cell death. Moreover, certain growth factors or correlated proteins act as biomarkers for AKI due to their sensitivity and specificity. Furthermore, growth factors originating from mesenchymal stem cells (MSCs) via paracrine signaling or extracellular vesicles recruit leukocytes or repair intrinsic cells and may participate in AKI repair or the AKI-CKD transition. In addition, growth factor-modified MSCs show superior therapeutic potential compared to that of unmodified controls. In this review, we summarized the current therapeutic and diagnostic strategies targeting growth factors to treat AKI in clinical trials. We also evaluated the possibilities of other growth factor-correlated molecules as therapeutic targets in the treatment of AKI and the AKI-CKD transition.

Brain-kidney interaction: Renal dysfunction following ischemic stroke

Stroke is a leading cause of mortality and morbidity, with long-term debilitating effects. Accumulating evidence from experimental studies as well as observational studies in patients suggests a cross talk between the brain and kidney after stroke. Stroke may lead to kidney dysfunction which can adversely impact patient outcome. In this review article, we discuss the epidemiology and mechanisms of brain–kidney interaction following ischemic stroke. Specifically, we discuss the role of the central autonomic network, autoregulation, inflammatory and immune responses, the role of extracellular vesicles and their cargo microRNA, in mediating brain–kidney interaction following stroke. Understanding the bidirectional nature of interaction between the brain and kidney after cerebral injury would have clinical implications for the treatment of stroke and overall patient outcome.

Deletion of Smad3 prevents renal fibrosis and inflammation in type 2 diabetic nephropathy

BACKGROUND

Transforming growth factor (TGF)-β/Smad3 signaling is highly activated in kidneys of patients with type 2 diabetic nephropathy (T2DN), however, the precise role of Smad3 in the pathogenesis of diabetic nephropathy remains unclear.

METHODS

Smad3 knockout (KO)-db/db mice were generated by intercrossing of male and female double-heterozygous Smad3^+/- db/m mice. Renal functions including urinary albumin excretion and serum creatinine were determined. Renal histological injury including renal fibrosis and inflammation were examined by periodic acid Schiff (PAS), periodic acid-silver methenamine (PASM), and immunohistochemistry (IHC) staining.

RESULTS

Smad3 knockout (KO)-db/db mice were protected from the development of diabetic kidney injury, characterized by the normal levels of urinary albumin excretion and serum creatinine without any evidence for renal fibrosis and inflammation. In contrast, Smad3 wild-type (WT) db/db and Smad3^+/- db/db mice developed progressively decline in renal function over the 12 to 32-week time course, including increased microalbuminuria and elevated levels of serum creatinine. Pathologically, Smad3 WT db/db and Smad3^+/- db/db mice exhibited a marked deposition of collagen-I (colI), collagen-IV(col-IV), and an increased infiltration of F4/80⁺ macrophages in kidney. Mechanistically, Smad3 deficiency decreased the lncRNA Erbb4-IR transcription, while increased miR-29b transcription and therefore protected the kidney from progressive renal injury in db/db mice.

CONCLUSION

Results from this study imply that Smad3 may represent as a novel and effective therapeutic target for T2DN.

Interleukin-17A induces renal fibrosis through the ERK and Smad signaling pathways

Interleukin (IL)-17A is upregulated in several renal diseases and plays a crucial role in renal inflammation. However, it remains unclear how IL-17A contributes to renal fibrosis. Our result demonstrated that IL-17A expression was upregulated in the obstructed kidney of unilateral ureter obstruction (UUO) mice when compared to the contralateral control kidney. Inhibition of IL-17A functions by the intravenous administration of an anti-IL-17A receptor antibody (100 μg) 2 h prior to UUO and on post-UUO day 1 and 3 significantly reduced fibronectin expression in the UUO kidney. The addition of IL-17A (25-100 μg) to human renal proximal tubular cells or renal fibroblasts caused an increase in fibronectin production and extracellular signal-regulated kinase (ERK)1/2 activation, which were reduced upon pretreatment with the ERK inhibitor U0126. The level of phosphorylated (p)-ERK1/2 was increased in the UUO kidney, but reduced by the administration of the anti-IL-17A receptor antibody, verifying the importance of the ERK pathway in vivo. TGF-β1 mRNA expression and protein were increased in the UUO kidney and in IL-17A-stimulated cultured cells. The administration of an anti-TGF-β1 neutralizing antibody or TGF-β1 receptor I inhibitor (SB431542) to cells abrogated the IL-17A-mediated increase of fibronectin production. IL-17A induced an increase in p-Smad2 and p-Smad3 expression at 7.5 min and 24 h and pretreatment with the anti-TGF-β1 neutralizing antibody, and SB431542 reduced the IL-17A-stimulated increase of p-Smad2. Knockdown of Smad2 or Smad3 expression inhibited the IL-17A-enhanced production of fibronectin. These results suggest an essential role for the TGF-β/Smad pathway in the IL-17A-mediated increase of fibronectin production. This study demonstrates that IL-17A contributes to the production of extracellular matrix, and targeting its associated signaling pathways could provide a therapeutic target for preventing renal fibrosis.

Histone Methyltransferases as Therapeutic Targets for Kidney Diseases

Emerging evidence has demonstrated that epigenetic regulation plays a vital role in gene expression under normal and pathological conditions. Alterations in the expression and activation of histone methyltransferases (HMTs) have been reported in preclinical models of multiple kidney diseases, including acute kidney injury, chronic kidney disease, diabetic nephropathy, polycystic kidney disease, and renal cell carcinoma. Pharmacological inhibition of these enzymes has shown promise in preclinical models of those renal diseases. In this review, we summarize recent knowledge regarding expression and activation of various HMTs and their functional roles in some kidney diseases. The preclinical activity of currently available HMT inhibitors and the mechanisms of their actions are highlighted.

Anti-fibrotic effects of synthetic TGF-β1 and Smad oligodeoxynucleotide on kidney fibrosis in vivo and in vitro through inhibition of both epithelial dedifferentiation and endothelial-mesenchymal transitions

Kidney fibrosis is a common process of various kidney diseases leading to end-stage renal failure irrespective of etiology. Myofibroblasts are crucial mediators in kidney fibrosis through production of extracellular matrix (ECM), but their origin has not been clearly identified. Many study proposed that epithelial and endothelial cells become myofibroblasts by epithelial dedifferentiation and endothelial-mesenchymal transition (EndoMT). TGF-β1/Smad signaling plays a crucial role in partly epithelial-mensencymal transition (EMT) and EndoMT. Thus, we designed the TGF-β1/Smad oligodeoxynucleotide (ODN), a synthetic short DNA containing complementary sequence for Smad transcription factor and TGF-β1 mRNA. Therefore, this study investigated the anti-fibrotic effect of synthetic TGF-β1/Smad ODN on UUO-induced kidney fibrosis in vivo model and TGF-β1-induced in vitro model. To examine the effect of TGF-β1/Smad ODN, we performed various experiments to evaluate kidney fibrosis. The results showed that UUO induced inflammation, ECM accumulation, epithelial dedifferentiation and EndoMT processes, and tubular atrophy. However, synthetic TGF-β1/Smad ODN significantly suppressed UUO-induced fibrosis. Furthermore, synthetic ODN attenuated TGF-β1-induced epithelial dedifferentiation and EndoMT program via blocking TGF-β1/Smad signaling. In conclusion, this study demonstrated that administration of synthetic TGF-β1/Smad ODN attenuates kidney fibrosis, epithelial dedifferentiation, and EndoMT processes. The findings propose the possibility of synthetic ODN as a new effective therapeutic tool for kidney fibrosis.

Delayed administration of suramin attenuates peritoneal fibrosis in rats

BACKGROUND

Peritoneal fibrosis is the most common complication of peritoneal dialysis, but there is currently no effective treatment. We previously reported that suramin pretreatment prevents the development of peritoneal fibrosis in a rat model of peritoneal fibrosis induced by chlorhexidine gluconate (CG). Here, we further examined the effectiveness of delayed administration of suramin on peritoneal fibrosis and the mechanism (s) involved in this process.

METHODS

In the rat model of peritoneal fibrosis induced by CG, suramin or saline was administered at day 21 and 28. All rats were then sacrificed to collect peritoneal tissues for Western blot analysis and histological staining at day 35.

RESULTS

Our results demonstrated that delayed administration of suramin starting at 21 days following CG injection can ameliorate peritoneal damage, with greater efficacy after two injections. Suramin also reduced the expression of α-smooth muscle actin, Collagen 1, and Fibronectin and suppressed phosphorylation of Smad-3, epidermal growth factor receptor (EGFR), signal transducers, activator of transcription 3 (STAT3) as well as extracellular signal-regulated kinases 1/2 (ERK 1/2) in the peritoneum injured with CG. Moreover, delayed administration of suramin inhibited overproduction of transforming growth factor-β1(TGF-β1) and expression of several pro-inflammatory cytokines, including monocyte chemoattractant protein-1, tumor necrosis factor-α, interleukin-1, and interleukin-6.

CONCLUSIONS

Our results indicated that suramin can attenuate progression of peritoneal fibrosis by a mechanism involving inhibition of the TGF-β1/Smad3 and EGFR signaling pathways as well as suppression of multiple proinflammatory cytokines. Thus, suramin may have the potential to offer an effective treatment for peritoneal fibrosis.

BMP-7 inhibits renal fibrosis in diabetic nephropathy via miR-21 downregulation

Epithelial-mesenchymal transition (EMT) and extracellular matrix (ECM) deposition in renal tubular epithelial cells are critical to diabetic nephropathy (DN) pathogenesis, but the underlying mechanisms remain undefined. Bone morphogenetic protein 7 (BMP-7) inhibits EMT and ECM accumulation in renal tubular epithelial cells cultured in presence of high glucose. Meanwhile, miRNA-21 (miR-21) downregulates Smad7, promoting EMT and ECM deposition. However, the association of BMP-7 with miR-21/Smad7 in DN is unknown. Here, NRK-52E cells incubated in presence of high glucose and STZ-induced C57BL diabetic mice were considered in vitro and in vivo models of DN, respectively. In both models, BMP-7 (mRNA/protein) amounts were decreased as well as Smad7 protein expression, while miR-21 expression and TGF-β1/Smad3 pathway activation were enhanced, accompanied by enhanced EMT and ECM deposition. Further, addition of BMP-7 human recombinant cytokine (rhBMP-7) and injection of the BMP-7 overexpression plasmid in diabetic mice markedly downregulated miR-21 and upregulated Smad7, reduced Smad3 activation without affecting TGF-β1 amounts, and prevented EMT and ECM accumulation. MiR-21 overexpression in the in vitro model downregulated Smad7, promoted EMT and ECM accumulation without affecting BMP-7 amounts, and miR-21 downregulation reversed it. By interfering with BMP-7 and miR-21 expression in high glucose conditions, miR-21 amounts and Smad3 phosphorylation were further decreased. Smad7 was then upregulated, and EMT and ECM deposition were inhibited; these effects were reversed after miR-21 overexpression. These findings suggest that BMP-7 decreases renal fibrosis in DN by regulating miR-21/Smad7 signaling, providing a theoretical basis for the development of novel and effective therapeutic drugs for DN.

Long noncoding RNA lnc-TSI inhibits renal fibrogenesis by negatively regulating the TGF-β/Smad3 pathway

Transforming growth factor-β (TGF-β) is a well-established central mediator of renal fibrosis, a common outcome of almost all progressive chronic kidney diseases. Here, we identified a poorly conserved and kidney-enriched long noncoding RNA in TGF-β1-stimulated human tubular epithelial cells and fibrotic kidneys, which we termed TGF-β/Smad3-interacting long noncoding RNA (lnc-TSI). Lnc-TSI was transcriptionally regulated by Smad3 and specifically inhibited TGF-β-induced Smad3 phosphorylation and downstream profibrotic gene expression. Lnc-TSI acted by binding with the MH2 domain of Smad3, blocking the interaction of Smad3 with TGF-β receptor I independent of Smad7. Delivery of human lnc-TSI into unilateral ureteral obstruction (UUO) mice, a well-established model of renal fibrosis, inhibited phosphorylation of Smad3 in the kidney and attenuated renal fibrosis. In a cohort of 58 patients with biopsy-confirmed IgA nephropathy (IgAN), lnc-TSI renal expression negatively correlated with the renal fibrosis index (r = -0.56, P < 0.001) after adjusting for cofounders. In a longitudinal study, 32 IgAN patients with low expression of renal lnc-TSI at initial biopsy had more pronounced increases in their renal fibrosis index and experienced stronger declines in renal function at repeat biopsy at a mean of 48 months of follow-up. These data suggest that lnc-TSI reduced renal fibrogenesis through negative regulation of the TGF-β/Smad pathway.

GdCl3 attenuates the glomerular sclerosis of streptozotocin (STZ) induced diabetic rats via inhibiting TGF-β/Smads signal pathway

Diabetic nephropathy (DN) is the most serious end-stage renal disease which characterized by renal glomerular sclerosis including glomerular hypertrophy, glomerular basement membrane (GBM) thickening, mesangial expansion and renal fibrosis. TGF-β/Smads signal pathway plays a crucial role in the development of renal fibrosis. In this study, we found that GdCl₃ which was an agonist of Calcium-sensing receptor (CaSR) could repress the activation of TGF-β/Smads signal pathway induced by TGF-β1 or high glucose and then alleviated the accumulation of extracellular matrix (ECM) in mesangial cells and the kidney of type1 diabetic rats. Further study indicated that GdCl₃ could induce the binding of CaSR and TβR II and then both of these two receptors translocated from cell membrane to cytoplasm, in this case, TβR II on the cell membrane was decreased and then desensitized to the stimulation of its ligand TGF-β1, so that the activation of its downstream factors such as Smad2 and Smad3 were blocked, finally, ECM expression in mesangial cells were inhibited. We concluded that GdCl₃ could alleviate the accumulation of ECM in mesangial cells via antagonizing TGF-β/Smads signal pathway in diabetes mellitus.

Post-transcriptional markers associated with clinical complications in Type 1 and Type 2 diabetes mellitus

The delayed diagnosis and the inadequate treatment of diabetes increase the risk of chronic complications. The study of regulatory molecules such as miRNAs can provide expression profiles of diabetes and diabetes complications. We evaluated the mononuclear cell miRNA profiles of 63 Type 1 and Type 2 diabetes patients presenting or not microvascular complications, and 40 healthy controls, using massive parallel sequencing. Gene targets, enriched pathways, dendograms and miRNA-mRNA networks were performed for the differentially expressed miRNAs. Six more relevant miRNAs were validated by RT-qPCR and data mining analysis. MiRNAs associated with specific complications included: i) neuropathy (miR-873-5p, miR-125a-5p, miR-145-3p and miR-99b-5p); ii) nephropathy (miR-1249-3p, miR-193a-5p, miR-409-5p, miR-1271-5p, miR-501-3p, miR-148b-3p and miR-9-5p); and iii) retinopathy (miR-143-3p, miR-1271-5p, miR-409-5p and miR-199a-5p). These miRNAs mainly targeted gene families and specific genes associated with advanced glycation end products and their receptors. Sets of miRNAs were also defined as potential targets for diabetes/diabetes complication pathogenesis.

A patent herbal drug Yi-Shen-Hua-Shi granule ameliorates C-BSA-induced chronic glomerulonephritis and inhabits TGFβ signaling in rats

ETHNOPHARMACOLOGY RELEVANCE

Yi-Shen-Hua-Shi (YSHS) granule is a modern Chinese patent drug for treating chronic glomerulonephritis (CGN). It is derived from a traditional Chinese medicine formula Sheng-Yang-Yi-Wei decoction that is used to treat CGN in ancient China. Pharmacological activities of YSHS granule have not been reported. In this work, we investigated the anti-CGN effects and TGFβ signaling-related mechanism of action of this herbal drug.

MATERIALS AND METHODS

The rat model of CGN was established by injection of cationization-bovine serum albumin (C-BSA) for five weeks. After finishing C-BSA injection, drugs were intragastrically administered to the rats once daily for four weeks. Clinical signs were recorded daily. Serum and urine biochemical parameters were analyzed by respective kits. Protein levels were examined by Western blotting. Pathological changes of renal tissues were evaluated by HE and Masson's trichrome staining.

RESULTS AND CONCLUSIONS

No significant differences in clinical signs and body weights were found among normal, model and drug treatment groups. Proteinuria; albuminuria; increased urine volume; elevated urea nitrogen, creatinine, total cholesterol and triglyceride levels in sera; decreased serum total protein and albumin; as well as renal pathological damage and fibrosis were observed in CGN model rats. YSHS granule ameliorated all the abnormal behavioral and biochemical changes in the model rats. Mechanical investigations showed that YSHS granule down-regulated proteins levels of TGFβ1, phospho-Smad2/3 (Thr 8) and Smad4 in rat renal tissues. In conclusion, YSHS granule demonstrates therapeutic effects in a rat model of CGN, and inhibition of the TGFβ/Smad signaling pathway is involved in the mechanism of action of the granule. This study provides a pharmacological basis for the use of modern YSHS granule and ancient Sheng-Yang-Yi-Wei decoction in treating CGN.

Proteasome inhibitor MG132 inhibits the process of renal interstitial fibrosis

The proteasome inhibitor pathway serves a crucial role in cell cycle progression and apoptosis, and in the activation of transcription factors and cytokines in tumor cells. The aim of the current study was to investigate the effect of the proteasome inhibitor, MG132, on transforming growth factor (TGF)-β1-induced expression of extracellular matrix proteins in rat renal interstitial fibroblasts (NRK-49F cells) and to better elucidate the mechanism by which MG132 functions. The level of connective tissue growth factor (CTGF), α-smooth muscle actin (SMA), fibronectin (FN) and collagen type III (Col III) in the MG132-pretreated groups was significantly decreased compared with groups treated with TGF-β1 alone. MG132 significantly decreased mRNA and the protein levels of fibrosis-associated factors induced by TGF-β1 treatment. The MG132-pretreated groups exhibited lower phosphorylated-mothers against decapentaplegic homolog (p-Smad)2, p-Smad3 and FN protein expression compared with the groups treated with TGF-β1 alone. In conclusion, MG132 reduced mRNA and protein expression of fibrosis-associated factors. It can successfully inhibit the inflammatory reaction induced by TGF-β via the Smad signaling pathway. These results indicate that MG132 appears to have a potent effect in counteracting renal fibrosis. MG132 may be applied in the treatment of patients with chronic kidney disease.

Inhibition of class I HDACs attenuates renal interstitial fibrosis in a murine model

Renal interstitial fibrosis is the most common of all the forms of chronic kidney disease (CKD). Research has shown that histone deacetylases (HDACs) participate in the process leading to renal fibrosis. However, the effects of class I HDAC inhibitors on the mechanisms of onset and progression of renal interstitial fibrosis are still unclear. Here, we present the effects and mechanisms of action of FK228 (a selective inhibitor of class I HDACs) in the murine model of unilateral ureteral obstruction (UUO) and in vitro models. We investigated the antifibrotic role of FK228 in a murine model of UUO. We used two key effector cell populations, rat renal interstitial fibroblasts and renal tubular epithelial cells exposed to recombinant transforming growth factor-beta 1 (TGF-β1), to explore the mechanistic pathways among in vitro models. The results indicated that FK228 significantly suppressed the production of extracellular matrix (ECM) in both in vivo and in vitro models. FK228 inhibited renal fibroblast activation and proliferation and increased the acetylation of histone H3. We found that FK228 also inhibited the small mothers against decapentaplegic (Smad) and non-Smad signaling pathways. So FK228 could significantly suppress renal interstitial fibrosis via Smad and non-Smad pathways. FK228 may be the basis for a new and effective medicine for alleviating renal fibrosis in the future.

Salvianolic Acids: Potential Source of Natural Drugs for the Treatment of Fibrosis Disease and Cancer

Salvianolic acids, the most effective and abundant compounds extracted from Salvia miltiorrhiza (Danshen), are well known for its good anti-oxidative activity. Danshen has been extensively used as a traditional medicine to treat cardiovascular-related diseases in China and other Asian countries for hundreds of years. Recently, more and more studies have demonstrated that salvianolic acids also have a good effect on the alleviation of fibrosis disease and the treatment of cancer. In vivo and in vitro experiments have demonstrated that salvianolic acids can modulate signal transduction within fibroblasts and cancer cells. It is discovered that the cancer treatment of salvianolic acids is not only because salvianolic acids promote the apoptosis of cancer cells, but also due to the inhibition of cancer-associated epithelial-mesenchymal transition processes. In this article, we review a variety of studies focusing on the comprehensive roles of salvianolic acids in the treatment of fibrosis disease and cancer. These perspectives on the therapeutic potential of salvianolic acids highlight the importance of these compounds, which could be the novel and attractive drugs for fibrosis disease and cancer.

MiR-101a ameliorates AngII-mediated hypertensive nephropathy by blockade of TGFβ/Smad3 and NF-κB signalling in a mouse model of hypertension

Hypertensive nephropathy, clinically characterized by progressive renal fibrosis and inflammation, is a severe complication of hypertension. The objectives of this study were to investigate the roles of miR-101a in relieving angiotensin II (Ang II)-mediated hypertensive nephropathy and uncover the possible underlying mechanisms. A hypertensive mouse model was established via continuous 28-day AngII infusion. Systolic blood pressure (SBP), ratio of urine albumin to creatinine, blood urea nitrogen (BUN), serum creatinine (Scr) and glomerular filtration rate (GFR) were evaluated. Dual luciferase reporter assay was used to explore the target of miR-101a. mRNA levels of miR-101a, TGFβRI, fibrotic markers (Collagen I and α-SMA) and pro-inflammatory cytokines (IL-1β and TNF-α) were determined by real-time PCR. Protein levels of TGFβRI, Collagen I, α-SMA, IL-1β, TNF-α, t-p65, P-p65, t-Smad3, P-Smad3, t-IκBα and P-IκBα were detected by western blot. MiR-101a mimics significantly improved GFR and inhibited AngII-induced increase in the ratio of urine albumin to creatinine, BUN and Scr. MiR-101a mimics partially abolished AngII-induced increase in the mRNA and protein level of fibrotic markers by targeting TGFβRI and inhibiting TGFβ/Smad3 pathway. Moreover, TGFβRI inhibitor galunisertib inhibited AngII-mediated renal injury in mice with hypertensive nephropathy. Additionally, miR-101a overexpression blocked AngII-induced up-regulation of pro-inflammatory markers via suppressing NF-κB pathway. MiR-101a exhibited protective effects against hypertensive nephropathy via inhibiting TGFβ/Smad3 and NF-κB signalling pathways.