Signaling Pathway In Fibrosis Research Articles

A Network Pharmacology Approach to Explore the Mechanism of HuangZhi YiShen Capsule for Treatment of Diabetic Kidney Disease.

Background and ObjectiveHuangZhi YiShen Capsule (HZYS) is a Chinese patent herbal drug that protects kidney function in diabetic kidney disease (DKD) patients. However, the pharmacologic mechanisms of HZYS remain unclear. This study would use network pharmacology to explore the pharmacologic mechanisms of HZYS.MethodsChemical constituents of HZYS were obtained through the Traditional Chinese Medicine Systems Pharmacology Database (TCMSP) and literature search. Potential targets of HZYS were identified by using the TCMSP and the SwissTarget Prediction databases. DKD-related target genes were collected by using the Online Mendelian Inheritance in Man, Therapeutic Target Database, GeneCards, DisGeNET, and Drugbank databases. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were carried out to further explore the mechanisms of HZYS in treating DKD. Molecular docking was conducted to verify the potential interactions between the prime compounds and the hub genes.Results179 active compounds and 620 target genes were obtained, and 571 common targets were considered potential therapeutic targets. The top 10 main active compounds of HZYS were heparin, quercetin, kaempferol, luteolin, methyl14-methylpentadecanoate, methyl (Z)-11-hexadecenoate, 17-hydroxycorticosterone, 4-pregnene-17α, 20β, 21-triol-3, 11-dione, wogonin, and hydroxyecdysone. Hub signaling pathways by which HZYS treating DKD were PI3K-Akt, MAPK, AGE-RAGE in diabetic complications, TNF, and apoptosis. The top 10 target genes associated with these pathways were IL6, MAPK1, AKT1, RELA, BCL2, JUN, MAPK3, MAP2K1, CASP3, and TNF. Quercetin and Luteolin were verified to have good binding capability with the hub potential targets IL6, MAPK1, AKT1 through molecular docking.ConclusionHZYS appeared to treat DKD by regulating the inflammatory, oxidative stress, apoptotic, and fibrosis signaling pathways. This study provided a novel perspective for further research of HZYS.

Biodegradable Stent with mTOR Inhibitor-Eluting Reduces Progression of Ureteral Stricture

In this study, we investigated the effect of mTOR inhibitor (mTORi) drug-eluting biodegradable stent (DE stent), a putative restenosis-inhibiting device for coronary artery, on thermal-injury-related ureteral stricture in rabbits. In vitro evaluation confirmed the dose-dependent effect of mTORi, i.e., rapamycin, on fibrotic markers in ureteral component cell lines. Upper ureteral fibrosis was induced by ureteral thermal injury in open surgery, which was followed by insertion of biodegradable stents, with or without rapamycin drug-eluting. Immunohistochemistry and Western blotting were performed 4 weeks after the operation to determine gross anatomy changes, collagen deposition, expression of epithelial–mesenchymal transition markers, including Smad, α-SMA, and SNAI 1. Ureteral thermal injury resulted in severe ipsilateral hydronephrosis. The levels of type III collagen, Smad, α-SMA, and SNAI 1 were increased 28 days after ureteral thermal injury. Treatment with mTORi-eluting biodegradable stents significantly attenuated thermal injury-induced urinary tract obstruction and reduced the level of fibrosis proteins, i.e., type III collagen. TGF-β and EMT signaling pathway markers, Smad and SNAI 1, were significantly modified in DE stent-treated thermal-injury-related ureteral stricture rabbits. These results suggested that intra-ureteral administration of rapamycin by DE stent provides modification of fibrosis signaling pathway, and inhibiting mTOR may result in fibrotic process change.

USP9X deubiquitinates connexin43 to prevent high glucose-induced epithelial-to-mesenchymal transition in NRK-52E cells

Epithelial-to-mesenchymal transition (EMT) plays an important role in diabetic nephropathy (DN). Ubiquitin-specific protease 9X (USP9X/FAM) is closely linked to TGF-β and fibrosis signaling pathway. However, it remains unknown whether USP9X is involved in the process of EMT in DN. Our previous study has shown that connexin 43 (Cx43) activation attenuated the development of diabetic renal tubulointerstitial fibrosis (RIF). Here, we showed that USP9X is a novel negative regulator of EMT and the potential mechanism is related to the deubiquitination and degradation of Cx43. To explore the potential regulatory mechanism of USP9X, the expression and activity of USP9X were studied by CRISPR/Cas9-based synergistic activation mediator (SAM) system, short hairpin RNAs, and selective inhibitor. The following findings were observed: (1) Expression of USP9X was down-regulated in the kidney tissue of db/db diabetic mice; (2) overexpression of USP9X suppressed high glucose (HG)-induced expressions of EMT markers and extra cellular matrix (ECM) in NRK-52E cells; (3) depletion of USP9X further aggravated EMT process and ECM production in NRK-52E cells; (4) USP9X deubiquitinated Cx43 and suppressed its degradation to regulate EMT process; (5) USP9X deubiquitinated Cx43 by directly binding to the C-terminal Tyr286 of Cx43. The current study determined the protective role of USP9X in the process of EMT and the molecular mechanism clarified that the protective effects of USP9X on DN were associated with the deubiquitination of Cx43.

GYY4137 attenuates functional impairment of corpus cavernosum and reduces fibrosis in rats with STZ-induced diabetes by inhibiting the TGF-β1/Smad/CTGF pathway

Erectile dysfunction (ED) is a common diabetic complication. Recent evidence has illuminated the role of hydrogen sulfide (H2S) as a dynamic mediator of the erection process. H2S is a potent endogenous relaxant gas. It has been shown to relax human and animal penile tissue in vitro and induce erection in animals in vivo. The reported penile expression of H2S-synthesizing enzymes also supports the potential role of the endogenous L-cysteine/H2S pathway in penile homeostasis. Several pathological changes take place in the diabetic penile tissue, including inflammation, oxidative stress, neuropathy and fibrosis of the corpus cavernosum (CC), the major erectile structure of the penis. The present study is experimental and has been performed in the diabetic rat model. The study will investigate the role of H2S as a potential protective mediator against diabetes-induced structural and functional alterations in the CC by examining if it: (1) reduces corporal contraction and/or enhances corporal relaxation following pharmacological stimulation, (2) attenuates fibromuscular changes in diabetic CC, and (3) whether there is a link with H2S plasma/urine level and CC tissue generation, as well as studying the expression of some proteins in the transforming growth factor (TGF)-β1-associated pathway. The major findings of the study reveal that- compared to the nondiabetic controls - the diabetic animals CC showed: (1) augmented contraction and attenuated relaxation in response to phenylephrine and carbachol, respectively, (2) marked fibromuscular degeneration with a significantly lower smooth muscle/collagen ratio and upregulation of TGF-β-1/Smad/CTGF fibrosis signaling pathway, (3) reduced H2S plasma and urinary levels and cavernosal tissue generation. Chronic GYY4137 treatment prevented most of these pathological changes in diabetic CC, thus may be considered a potential new strategy for the prevention and/or treatment of diabetes-induced ED.

Network Meta-Analysis on the Mechanisms Underlying Alcohol Augmentation of COVID-19 Pathologies.

BackgroundThe coronavirus disease 2019 (COVID‐19) pandemic is a worldwide crisis caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). Many COVID‐19 patients present with fever in the early phase, with some progressing to a hyperinflammatory phase. Ethanol (EtOH) exposure may lead to systemic inflammation. Network meta‐analysis was conducted to examine possible relationships between EtOH consumption and COVID‐19 pathologies.MethodsMolecules affected by EtOH exposure were identified by analysis with QIAGEN Knowledge Base. Molecules affected by COVID‐19 were identified from studies in MEDLINE, bioRxiv, and medRxiv reporting gene expression profiles in COVID‐19 patients, QIAGEN Coronavirus Network Explorer, and analysis of the RNA‐sequencing data of autopsied lungs of COVID‐19 patients retrieved from the GEO database. Network meta‐analysis was then conducted on these molecules using QIAGEN Ingenuity Pathway Analysis (IPA).ResultsTwenty‐eight studies reporting significant gene expression changes in COVID‐19 patients were identified. One RNA‐sequencing dataset on autopsied lungs of COVID‐19 patients was retrieved from GEO. Our network meta‐analysis suggests that EtOH exposure may augment the effects of SARS‐CoV‐2 infection on hepatic fibrosis signaling pathway, cellular metabolism and homeostasis, inflammation, and neuroinflammation. EtOH may also enhance the activity of key mediators including cytokines, such as IL‐1β, IL‐6, and TNF, and transcription factors, such as JUN and STAT, while inhibiting the activity of anti‐inflammatory mediators including glucocorticoid receptor. Furthermore, IL‐1β, IL‐6, TNF, JUN, and STAT were mapped to 10 pathways predicted to associate with SARS‐CoV‐2 proteins, including HMGB1, IL‐1, and IL‐6 signaling pathways.ConclusionsOur meta‐analyses demonstrate that EtOH exposure may augment SARS‐CoV‐2–induced inflammation by altering the activity of key inflammatory mediators. Our findings suggest that it is important for clinicians to caution patients about the risk of alcohol consumption, which has increased during the COVID‐19 pandemic. The findings also call for further investigation into how alcohol exposure affects viral infections.

Progress in the study of pulmonary fibrosis signaling pathways caused by paraquat poisoning

Paraquat is a quaternary ammonium herbicide, which can be distributed in lung, liver, kidney, heart, brain and other organs through blood circulation, leading to multiple organ failure, especially lung injury. Due to the lack of effective treatment methods and specific antidotes, the prognosis of most patients with paraquat poisoning is very poor. The treatment of paraquat poisoning was a big problem for emergency doctors. Previous studies have found that pulmonary fibrosis caused by paraquat poisoning is closely related to a variety of pathological processes, such as oxidative stress, inflammatory reaction, mitochondrial damage, imbalance of extracellular matrixproduction (ECM) and degradation, which involve the activation or inhibition of various signaling pathways. In recent years, many researchers focused on clarifying the mechanism of paraquat induced pulmonary fibrosis, and some signaling pathways related to paraquat poisoning leading to pulmonary fibrosis have been found. A large number of studies have found that adenosine monophosphate activated protein kinase (AMPK) related signaling pathway, transforming growth factor-β/Smad (TGF-β/Smad) signaling pathway, mitogen-activated protein kinase (MAPK) related signaling pathway, Ras homolog gene/Rho associated kinases (Ras/ROCK) and Wnt/β-catenin signal pathways are closely related to paraquat induced pulmonary fibrosis. In this paper, we reviewed signaling pathways related to paraquat induced pulmonary fibrosis, in order to provide more ideas for the clinical treatment of paraquat induced pulmonary fibrosis.

Network Meta-analysis on the Molecular Mechanisms of Palmitic Acid in Liver Fibrosis

Elevated levels of free fatty acids have been suggested as the main factors contributing to the development of non-alcoholic steatohepatitis. This study conducted network meta-analysis using the QIAGEN Ingenuity Pathway Analysis (IPA) to examine the roles of saturated fatty acids (SFAs) and n-3 unsaturated fatty acids (UFAs) in the activation of Hepatic Fibrosis Signaling Pathway and collagen accumulation. Our analysis identified the shortest paths from palmitic acid (PA), a SFA, to the Hepatic Fibrosis Signaling Pathway, and found that elevated level of PA may increase the activities of transcription factors, such as CEBPβ, JUN/FOS, NFκB, and PPARγ, cytokines/chemokines/growth factors, such as TNF, IL1, CCL2, CCN2, LEP, and TGFβ1, oxidative stress mediators, such as NOX, and fibrinolysis regulators, such as SERPINE1, which may in turn activate the Hepatic Fibrosis Signaling Pathway. Our analysis also identified the shortest paths from PA to collagen accumulation and found that elevated level of PA may increase the activities of signaling mediators, such as ERK1/2, cytokines/chemokines/growth factors, such as TNF, IL6, CCL2, CCN2, LEP, and TGFβ1, which may in turn increase the accumulation of collagens. In contrast, the increased levels of n-3 UFAs inhibited the activities of PDGFA, PDGFB, TNF, IL1, and CCL2. Our analysis also identified seven PA- and liver fibrosis-associated molecules mapped to the shortest paths from PA the Hepatic Fibrosis Signaling Pathway and from PA to collagens. Mapping of these seven molecules, TNF, IL1A, CCL2, TGFβ1, CCN2, LEP, and SERPINE1, to the Hepatic Fibrosis Signaling Pathway showed that these molecules may lead to proinflammatory response in the liver, reduced ECM degradation, and enhanced ECM accumulation. Our studies shed light on the molecular mechanisms by which PA contributes to liver fibrosis and the key mediating molecules that may be used for further research and therapeutic intervention.

Effects of maslinic acid on isoproterenol-induced myocardial fibrosis in mice

Objective: To investigate the effect of maslinic acid (MA) on isoproterenol (ISO)-induced myocardial fibrosis in mice. Methods: ISO was used to induce myocardial fibrosis in adult male C57BL/6 mice, and MA was administered for two weeks to detect the effects of MA on cardiac function and fibrosis. Molecular changes of fibrosis markers and signaling pathways were detected by RT-PCR and western blotting. Phosphate buffer saline (PBS), PBS+SB203580 (p38 MAPK inhibitor), PBS+MA, ISO, ISO+SB203580, ISO+MA were added to the primary cultured rat fibroblasts. Cells were collected after 48 h for subsequent detection. Results: In this study, the mouse model of myocardial fibrosis was successfully established. The left ventricular faction shortening (FS) and maximum rate of rise and maximum rate of fall of pressure in left ventricular chamber (±dp/dt) of the ISO+MA group were significantly higher than those of the ISO group ((35.1±1.8)% vs (28.5±2.6)%, (7 256±153) mmHg/s vs (6 402±240) mmHg/s, (7 156±163) mmHg/s vs (6 319±219) mmHg/s, all P<0.05). The levels of interstitial and perivascular collagen deposition in the ISO+MA group were higher than those in the ISO group (P<0.05), the relative mRNA levels of COL-1, COL-3 and TGF-β in the ISO+MA group were significantly lower than those in the ISO group, with the relative expression levels of 1.70±0.24 vs 3.69±0.34, 1.72±0.56 vs 4.84±0.82, 1.52±0.19 vs 2.64±0.29, respectively (all P<0.05). The phosphorylation levels of p38 MAPK, Smad3 and protein expression level of TGF-β1 in ISO+MA group were lower than those in ISO group (relative expression levels were 1.67±0.35 vs 2.61±0.58, 1.68±0.23 vs 2.52±0.19,1.56±0.15 vs 2.48±0.26, respectively, all P<0.05). The results of in vitro cell experiments showed that the mRNA levels of COL-1, COL-3 and TGF-β in the SB203580 and MA groups were significantly lower than those in the ISO group (relative expression levels were 2.25±0.51, 2.16±0.48 vs 5.29±1.21; 1.58±0.34, 1.69±0.29 vs 4.97±1.32; 1.41±0.31, 1.55±0.38 vs 3.53±0.56, respectively, all P<0.05). The phosphorylation levels of p38 MAPK and Smad3 in the SB203580 MA groups was significantly lower than those in the ISO group, and the protein expression level of TGF-β1 was lower than that in the ISO group (1.81±0.18, 1.77±0.16 vs 2.56±0.32; 1.85±0.21, 1.81±0.17 vs 2.48±0.37; 1.84±0.24, 1.72±0.17 vs 2.52±0.29, all P<0.05). Conclusion: Maslinic acid can inhibit the phosphorylation of p38 MAPK, thereby preventing the canonical TGF-β1/Smads fibrosis signaling pathway to achieve an anti-fibrosis role.

Abstract 709: DNA Damage-free iPS-cardiomyocyte Reduces Cardiac Fibrosis Through Downmodulation of Exosomal miR-101

With the growing field of myocardial repair through transplantation of cardiomyocytes (CM) derived from human induced pluripotent stem cells (iPSC) calls for a method for reducing fibrotic tissue development at the site of cell transplantation. We tested the hypothesis of whether transplanting CMs derived from DNA damage-free (DdF) iPSCs could reduce the recruitment of myofibroblasts and reduce fibrosis at the site of transplantation. Transcription factor p53 functions are DNA damage-dependent: induce apoptosis in DNA damaged cells while promoting cell cycle in normal cells. Utilizing this discriminating nature of p53 we selected iPSCs that are DdF and differentiated them into CMs. Control CMs (Ctrl-CM) and DdF-CMs were tested for transplantation induced fibrosis in a mouse model. The inflammatory markers such as accumulation of ROS, superoxide and DNA damage were significantly reduced in DdF cells. RNA sequencing revealed that, in DdF-CMs, the inflammatory and fibrosis signaling pathways are significantly different compared to Ctrl-CMs. Transplantation of both CMs into the myocardium of ischemia-induced mice resulted in fibrosis around the transplantation site. However, the fibrotic area around transplanted sites and total fibrosis were significantly reduced in mice hearts that received DdF-CMs as evidenced by collagen accumulation and Sirus red staining of fibrotic tissue. Importantly, the number of myofibroblasts at the site of DdF-CM transplantation was significantly reduced compared to Ctrl-CM sites. In an in vitro migration study, fibroblasts preferentially migrated towards the Ctrl-CMs. Human fibroblast treatment with DdF-CM exosomes (DdF-Exo) resulted in reduced expression of fibrotic markers than Ctrl-CM exosomes (Ctrl-Exo) treatment. miRNA analysis in exosomes showed that the anti-inflammatory miR-26a is upregulated and the inflammatory miRNA101 is downregulated in DdF-Exo. Overexpression of miR-101 mimic in DdF-Exo abrogated the anti-fibrotic potential property of DdF-Exo. Our results clearly demonstrate that DdF-CMs has anti-fibrotic potential. Transplanting DdF-CMs attracted reduced myofibroblast to the engraft site and Ctrl-CMs transplantation induce fibrosis through the expression of exosomal miR-101.

Role of the Notch Signaling Pathway in Fibrosis of Denervated Skeletal Muscle.

In order to investigate the role of the Notch signaling pathway in skeletal muscle fibrosis after nerve injury, 60 Sprague-Dawley rats were selected and divided randomly into a control and two experimental groups. Group A served as controls without any treatment. Rats in groups B were injected intraperitoneally with 0.2 mL PBS and those in group C were injected intraperitoneally with 0.2 mL PBS+100 μmol/L, 0.2 mL N-[N-(3,5-difluorophenacetyl)-l-alanyl]- S-phenylglycine t-butyl ester (DAPT, a gamma-secretase inhibitor that suppresses Notch signaling) respectively, on postoperative days 1, 3, 7, 10, and 14 in a model of denervation-induced skeletal muscle fibrosis by right sciatic nerve transection. Five rats from each group were euthanized on postoperative days 1, 7, 14, and 28 to collect the right gastrocnemii, and hematoxylin and eosin (HE) staining, immunohistochemistry test, real-time PCR, and Western blotting were performed to assess connective tissue hyperplasia and fibroblast density as well as expression of Notch 1, Jagged 1, and Notch downstream molecules Hes 1 and collagen I (COL I) on day 28. There was no significant difference in HE-stained fibroblast density between group B and C on postoperative day 1. However, fibroblast density was significantly higher in group B than in group C on postoperative days 7, 14, and 28. Notch 1, Jagged 1, Hes 1, and COL I proteins in the gastrocnemius were expressed at very low levels in group A but at high levels in group B. Expression levels of these proteins were significantly lower in group C than in group B (P<0.05), but they were higher in group C than in group A (P<0.05) on postoperative day 28. We are led to conclude that locking the Notch signaling pathway inhibits fibrosis progression of denervated skeletal muscle. Thus, it may be a new approach for treatment of fibrosis of denervated skeletal muscle.

Inhibitory Effect of Corilagin on miR-21-Regulated Hepatic Fibrosis Signaling Pathway.

Corilagin is a polyphenol that can be extracted from many medicinal plants and shows multiple pharmacological effects. We aimed to investigate the role of corilagin on miR-21-regulated hepatic fibrosis, especially miR-21-regulated TGF-1/Smad signaling pathway, in hepatic stellate LX2 cell line and Sprague-Dawley rats. The mRNA or protein levels of miR-21, Smad7, connective tissue growth factor (CTGF), -smooth muscle actin (-SMA), tissue inhibitor of metalloproteinase-1 (TIMP-1), matrix metalloproteinase-9 (MMP-9), collagen type I alpha 1 (COL1A1), Smad2, Smad3, Smad2/3, p-Smad2, p-Smad3, p-Smad2/3, and transforming growth factor-1 (TGF-1) in LX2 cells and liver tissues were determined. Furthermore, gain-of and loss-of function of miR-21 in miR-21-regulated TGF-1/Smad signaling pathway were analyzed in LX2 cells. Liver tissues and serum were collected for pathological analysis, immunohistochemical staining, and enzyme-linked immunosorbent assay (ELISA). Corilagin treatment reduced mRNA or protein levels of miR-21, CTGF, -SMA, TIMP-1, TGF-1, COL1A1, p-Smad2, p-Smad3, and p-Smad2/3 both in vitro and in vivo. While corilagin increased mRNA and protein levels of Smad7 and MMP-9. After gain-of and loss-of function of miR-21, the downstream effectors of miR-21-regulated TGF-1/Smad signaling pathway in LX2 cells changed accordingly, and the changes were inhibited by corilagin. Simultaneously, administration of corilagin not only ameliorated pathological manifestation of liver fibrosis but also reduced levels of -SMA and COL1A1 in liver tissues and TGF-1, ALT levels in serum. Corilagin is able to potentially prevent liver fibrosis by blocking the miR-21-regulated TGF-1/Smad signaling pathway in LX2 cells and CCl4-induced liver fibrosis rats, which may provide a novel therapeutic strategy for liver fibrosis.

Comprehensive Lipidome and Proteome Analyses to Identify the Inflammatory and Cardiometabolic Fingerprints of Metabolically “Healthy” Versus “Unhealthy” Obese Subjects

Study ObjectiveObesity‐related co‐morbidities pose a serious health care system burden. However, 30% of obese subjects do not present with cardiometabolic complications. Here we perform comprehensive lipidome and proteome analyses to identify inflammatory and cardiometabolic fingerprints that characterize metabolically healthy obese (MHO) and metabolically unhealthy obese (MUO) phenotypes.MethodsObese patients (BMI 35–50) donated plasma before undergoing bariatric surgery (clinicaltrial.gov NCT02322073). Patients were classified as MHO (n=5) versus MUO (n=9) according to International Diabetes Federation criteria. Metabolically healthy lean (MHL, n=14) subjects were age‐ and sex‐matched to the obese cohort. Plasma samples were analyzed for 480 protein biomarkers related to inflammation and cardiometabolic processes in a multiplexed array. Samples were also subjected to untargeted lipidomics and targeted oxylipin lipidomics analyses.ResultsGene‐ontology term analysis of the 15 proteins that were significantly decreased/elevated in MHO vs. MUO patients revealed differences in inflammation, metabolism, apoptosis and fibrosis signaling pathways. Furthermore, lipidomics show distinct differences in the lipid profile of MHO and MUO groups. The MUO group displayed increased levels of ceramides, which are implicated in development of insulin resistance and cardiovascular diseases. In contrast, the MHO group exhibited increased levels of anandamide and dihomo‐gamma‐linolenoyl ethanolamide, which are lipids associated with anti‐inflammatory effects. The MUO group also exhibited elevated levels of the cardiometabolic risk factor plasminogen activator inhibitor 1 (PAI‐1). Interestingly, MHO patients presented with increased levels of myeloblastin, which is a serine protease that degrades the PAI‐1–stabilizing protein vitronectin.ConclusionIn conclusion, we have performed a comprehensive lipidomic and proteomic fingerprinting of MHO and MUO subjects. Our analyses reveal clear stratification of the groups and identify lipid mediators that may be of possible therapeutic use as novel interventions for obesity‐associated pathophysiologies. Work is ongoing to explore the molecular mechanism by which the identified proteins and lipid mediators affect cardiometabolic health in obese patients.Support or Funding InformationThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

THE CROSS-TALK OF SALIDROSIDE ON TGF-B/SMADS AND WNT/B-CATENIN SIGNALING PATHWAY IN THE MYOCARDIAL FIBROSIS AFTER ACUTE MYOCARDIAL INFARCTION IN RATS AND ITS CORRELATION WITH GALECTIN-3

Background: TGF-β/Smads and Wnt/β-catenin pathway are recognized as the most important myocardial fibrosis signaling pathway. Recent studies reported Salidroside(Salid) on the angiogenesis and apoptosis in liver fibrosis, while there was no evidence of Salid on preventing or reversing myocardial

Excess mechanical stress and hydrogen peroxide remodel extracellular matrix of cultured human uterosacral ligament fibroblasts by disturbing the balance of MMPs/TIMPs via the regulation of TGF‑β1 signaling pathway.

The regulation of the extracellular matrix (ECM) by mechanical stress is of interest as the ECM is essential in the development of pelvic organ prolapse. In the present study, the effect of overexposure to mechanical stress on the ECM, and the probable underlying mechanisms in cultured human uterosacral ligament fibroblasts (hUSLFs), was explored. Mechanical stress has an effect on oxidation‑antioxidation products in parametrial ligament fibroblasts. Thus, hUSLFs were incubated with different concentrations of hydrogen peroxide to elucidate any potential interactions. Excess mechanical stress and H2O2 inhibited cell proliferation, and decreased mRNA and protein expression levels of ECM components, collagen 1, collagen 3 and elastin. Further analysis revealed that the mRNA expression level of matrix metalloproteinase‑2 (MMP‑2) was increased and TIMP metallopeptidase inhibitor2 (TIMP‑2) decreased, and in addition the MMP2/TIMP2 mRNA ratio was increased, which may facilitate the degradation of the ECM. Due to the key role of the transforming growth factor β1 (TGF‑β1)/mothers against decapentaplegic homolog 2 (Smad2) signaling pathway in fibrosis, the present study investigated the effect of excess mechanical stress and H2O2 on TGF‑β1/Smad2 signaling. The results indicated that excess mechanical stress and H2O2 treatment suppressed phosphorylated Smad2 expression and decreased the levels of TGF‑β1. Activation of the TGF‑β1 signaling pathway by either mechanical stress or H2O2 was demonstrated to attenuate cell proliferation and ECM components, and also increased the MMP2/TIMP2 mRNA ratio. These findings suggested that mechanical stress and H2O2 overexposure inhibit cell proliferation and remodel the ECM network via regulation of the TGF‑β1 signaling pathway.

Regulatory Mechanisms of the Molecular Pathways in Fibrosis Induced by MicroRNAs.

Objective:MicroRNAs (miRNAs or miRs) play critical roles in the fibrotic process in different organs. We summarized the latest research progress on the roles and mechanisms of miRNAs in the regulation of the molecular signaling pathways involved in fibrosis.Data Sources:Papers published in English from January 2010 to August 2015 were selected from the PubMed and Web of Science databases using the search terms “microRNA”, “miR”, “transforming growth factor β”, “tgf β”, “mitogen-activated protein kinase”, “mapk”, “integrin”, “p38”, “c-Jun NH2-terminal kinase”, “jnk”, “extracellular signal-regulated kinase”, “erk”, and “fibrosis”.Study Selection:Articles were obtained and reviewed to analyze the regulatory effects of miRNAs on molecular signaling pathways involved in the fibrosis.Results:Recent evidence has shown that miRNAs are involved in regulating fibrosis by targeting different substrates in the molecular processes that drive fibrosis, such as immune cell sensitization, effector cell activation, and extracellular matrix remodeling. Moreover, several important molecular signaling pathways involve in fibrosis, such as the transforming growth factor-beta (TGF-β) pathway, mitogen-activated protein kinase (MAPK) pathways, and the integrin pathway are regulated by miRNAs. Third, regulation of the fibrotic pathways induced by miRNAs is found in many other tissues in addition to the heart, lung, liver, and kidney. Interestingly, the actions of many drugs on the human body are also induced by miRNAs. It is encouraging that the fibrotic process can be blocked or reversed by targeting specific miRNAs and their signaling pathways, thereby protecting the structures and functions of different organs.Conclusions:miRNAs not only regulate molecular signaling pathways in fibrosis but also serve as potential targets of novel therapeutic interventions for fibrosing diseases.

HIPK2 is a new drug target for anti-fibrosis therapy in kidney disease.

In vitro and animal studies continue to elucidate the mechanisms of fibrosis and have led to advancements in treatment for idiopathic pulmonary fibrosis and cirrhosis, but the search for treatments for renal fibrosis has been more disappointing. Here, we will discuss homeodomain-interacting-protein kinase 2 (HIPK2), a novel regulator of fibrosis that acts upstream of major fibrosis signaling pathways. Its key role in renal fibrosis has been validated in vitro and in several murine models of chronic kidney diseases (CKD).