TGF-β/Smad and JAK/STAT pathways are involved in the anti-fibrotic effects of propylene glycol alginate sodium sulphate on hepatic fibrosis

S100A8/A9 promotes endometrial fibrosis via regulating RAGE/JAK2/STAT3 signaling pathway

Intrauterine adhesion (IUA) is characterized by endometrial fibrosis. S100A8/A9 plays an important role in inflammation and fibroblast activation. However, the role of S100A8/A9 in IUA remains unclear. In this study, we collect normal and IUA endometrium to verify the expression of S100A8/A9. Human endometrial stromal cells (hEnSCs) are isolated to evaluate fibrosis progression after S100A8/A9 treatment. A porcine IUA model is established by electrocautery injury to confirm the therapeutic effect of menstrual blood-derived stromal cells (MenSCs) on IUA. Our study reveals increased S100A8/A9 expression in IUA endometrium. S100A8/A9 significantly enhances hEnSCs proliferation and upregulates fibrosis-related and inflammation-associated markers. Furthermore, S100A8/A9 induces hEnSCs fibrosis through the RAGE-JAK2-STAT3 pathway. Transplantation of MenSCs in a porcine IUA model notably enhances angiogenesis, mitigates endometrial fibrosis and downregulates S100A8/A9 expression. In summary, S100A8/A9 induces hEnSCs fibrosis via the RAGE-JAK2-STAT3 pathway, and MenSCs exhibit marked effects on endometrial restoration in the porcine IUA model.

Antioxidant therapy against TGF-β/SMAD pathway involved in organ fibrosis

Fibrosis refers to excessive build-up of scar tissue and extracellular matrix components in different organs. In recent years, it has been revealed that different cytokines and chemokines, especially Transforming growth factor beta (TGF-β) is involved in the pathogenesis of fibrosis. It has been shown that TGF-β is upregulated in fibrotic tissues, and contributes to fibrosis by mediating pathways that are related to matrix preservation and fibroblasts differentiation. There is no doubt that antioxidants protect against different inflammatory conditions by reversing the effects of nitrogen, oxygen and sulfur-based reactive elements. Oxidative stress has a direct impact on chronic inflammation, and as results, prolonged inflammation ultimately results in fibrosis. Different types of antioxidants, in the forms of vitamins, natural compounds or synthetic ones, have been proven to be beneficial in the protection against fibrotic conditions both in vitro and in vivo. In this study, we reviewed the role of different compounds with antioxidant activity in induction or inhibition of TGF-β/SMAD signalling pathway, with regard to different fibrotic conditions such as gastro-intestinal fibrosis, cardiac fibrosis, pulmonary fibrosis, skin fibrosis, renal fibrosis and also some rare cases of fibrosis, both in animal models and cell lines.

Noxious ramifications of cosmetic pollutants on gastrointestinal microbiome: A pathway to neurological disorders

On exposure to cosmetic pollutants, gastrointestinal dysbiosis, which is characterised by a disturbance in the gut microbiota, has come into focus as a possible contributor to the occurrence of neurotoxic consequences. It is normal practice to use personal care products that include parabens, phthalates, sulphates, triclosans/triclocarbans and micro/nano plastics. These substances have been found in a variety of bodily fluids and tissues, demonstrating their systemic dispersion. Being exposed to these cosmetic pollutants has been linked in recent research to neurotoxicity, including cognitive decline and neurodevelopmental problems. A vital part of sustaining gut health and general well-being is the gut flora. Increased intestinal permeability, persistent inflammation, and impaired metabolism may result from disruption of the gut microbial environment, which may in turn contribute to neurotoxicity. The link between gastrointestinal dysbiosis and the neurotoxic effects brought on by cosmetic pollutants may be explained by a number of processes, primarily the gut-brain axis. For the purpose of creating preventative and therapeutic measures, it is crucial to comprehend the intricate interactions involving cosmetic pollutants, gastrointestinal dysbiosis, and neurotoxicity. This review provides an in-depth understanding of the various hazardous cosmetic pollutants and its potential role in the occurrence of neurological disorders via gastrointestinal dysbiosis, providing insights into various described and hypothetical mechanisms regarding the complex toxic effects of these industrial pollutants.

Mitochondrial-mediated nuclear remodeling and macrophage polarizations: A key switch from liver fibrosis to HCC progression

Liver fibrosis is a significant health burden worldwide and has emerged as the leading cause of Hepatocellular carcinoma (HCC) incidence. Mitochondria are the dynamic organelles that regulate the differentiation, survival, and polarization of macrophages. Nuclear-DNA-associated proteins, micro-RNAs, as well as macrophage polarization are essential for maintaining intracellular and extra-cellular homeostasis in the liver parenchyma. Dysregulated mitochondrial coding genes (ETS complexes I, II, III, IV, and V), non-coding RNAs (mitomiRs), and nuclear alteration lead to the production of reactive oxygen species (ROS) and inflammation which are implicated in the transition of liver fibrosis into HCC. Recent findings indicated the protecting effect of E74-like factor 3/peroxisome proliferator-activated receptor-γ (Elf-3/PPAR-γ). HDAR-y inhibits the deacetylation of PPAR-y and maintains the PPAR-y pathway. Elf-3 plays a tumor suppressive role through epithelial-mesenchymal transition-related gene and zinc finger E-box binding homeobox 2 (ZEB-2) domain. Additionally, the development of HCC includes the PI3K/Akt/mTOR and transforming Growth Factor β (TGF-β) pathway that promotes the Epithelial-mesenchymal transition (EMT) through Smad/Snail/Slug signaling cascade. In contrast, the TLR2/NOX2/autophagy axis promotes M2 polarization in HCC. Thus, a thorough understanding of the mitochondrial and nuclear reciprocal relationship related to macrophage polarization could provide new research opportunities concerning diseases with a significant impact on liver parenchyma towards developing liver fibrosis or liver cancer. Moreover, this knowledge can be used to develop new therapeutic strategies to treat liver diseases.

Marine algal polysaccharides as future potential constituents against non-alcoholic steatohepatitis

Non-alcoholic steatohepatitis (NASH) is one of the most chronic and incurable liver diseases triggered mainly by an inappropriate diet and hereditary factors which burden liver metabolic stress, and may result in liver fibrosis or even cancer. While the available drugs show adverse side effects. The non-toxic bioactive molecules derived from natural resources, particularly marine algal polysaccharides (MAPs), present significant potential for treating NASH. In this review, we summarized the protective effects of MAPs on NASH from multiple perspectives, including reducing oxidative stress, regulating lipid metabolism, enhancing immune function, preventing fibrosis, and providing cell protection. Furthermore, the mechanisms of MAPs in treating NASH were comprehensively described. Additionally, we highlight the influences of the special structures of MAPs on their bioactive differences. Through this comprehensive review, we aim to further elucidate the molecular mechanisms of MAPs in NASH and inspire insights for deeper research on the functional food and clinical applications of MAPs.

Salvianolic acid A suppresses CCl4-induced liver fibrosis through regulating the Nrf2/HO-1, NF-κB/IκBα, p38 MAPK, and JAK1/STAT3 signaling pathways

Salvianolic acid A (SA-A), a water-soluble compound extracted from traditional Chinese herb Radix Salvia miltiorrhiza, has anti-fibrotic effects on carbon tetrachloride (CCl₄)-induced liver fibrosis. However, the underlying molecular mechanism remains unclear. Thus, this study aimed to elucidate the molecular mechanism underlying the anti-fibrotic effects of SA-A on CCl₄-induced liver fibrosis in mice. All mice (except control group) were intraperitoneally administered CCl₄ dissolved in peanut oil to induce liver fibrosis. Treatment groups were then gavaged with SA-A (20 or 40 mg/kg). The liver function index; liver fibrosis index; and superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione peroxidase (GSH-Px) levels were determined. Furthermore, histopathological changes in liver tissues were observed via hematoxylin-eosin and Masson's trichrome staining. The expression of α-smooth muscle actin (α-SMA) and collagen I was detected using immunofluorescence, and the mRNA levels of inflammatory factors were determined using quantitative polymerase chain reaction. Finally, western blotting and immunofluorescence were used to determine the expression levels of proteins related to Nrf2/HO-1, NF-κB/IκBα, p38 MAPK, and JAK1/STAT3 signaling pathways. The results showed that SA-A could ameliorate CCl₄-induced liver injury and liver fibrosis, improve morphology, and alleviate collagen deposition in the fibrotic liver. Moreover, SA-A could regulate the Nrf2/HO-1, NF-κB/IκBα, p38 MAPK, and JAK1/STAT3 signaling pathways; increase the levels of SOD and GSH-Px; and decrease MDA level in the fibrotic liver. Collectively, our study findings indicate that SA-A is effective in preventing liver fibrosis in mice by inhibiting inflammation and oxidative stress via regulating the Nrf2/HO-1, NF-κB/IκBα, p38 MAPK, and JAK1/STAT3 signaling pathways.

Baricitinib Attenuates Bleomycin-Induced Pulmonary Fibrosis in Mice by Inhibiting TGF-β1 Signaling Pathway

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial lung disease with unknown etiology, high mortality and limited treatment options. It is characterized by myofibroblast proliferation and extensive deposition of extracellular matrix (ECM), which will lead to fibrous proliferation and the destruction of lung structure. Transforming growth factor-β1 (TGF-β1) is widely recognized as a central pathway of pulmonary fibrosis, and the suppression of TGF-β1 or the TGF-β1-regulated signaling pathway may thus offer potential antifibrotic therapies. JAK-STAT is a downstream signaling pathway regulated by TGF-β1. JAK1/2 inhibitor baricitinib is a marketed drug for the treatment of rheumatoid arthritis, but its role in pulmonary fibrosis has not been reported. This study explored the potential effect and mechanism of baricitinib on pulmonary fibrosis in vivo and in vitro. The in vivo studies have shown that baricitinib can effectively attenuate bleomycin (BLM)-induced pulmonary fibrosis, and in vitro studies showed that baricitinib attenuates TGF-β1-induced fibroblast activation and epithelial cell injury by inhibiting TGF-β1/non-Smad and TGF-β1/JAK/STAT signaling pathways, respectively. In conclusion, baricitinib, a JAK1/2 inhibitor, impedes myofibroblast activation and epithelial injury via targeting the TGF-β1 signaling pathway and reduces BLM-induced pulmonary fibrosis in mice.

Klotho improves cardiac fibrosis, inflammatory cytokines, ferroptosis, and oxidative stress in mice with myocardial infarction

The anti-aging protein Klotho has been associated with cardiovascular health protection. Nevertheless, the protective mechanism remains unknown. The present study is aimed at exploring the effect of Klotho on cardiac remodeling and its potential mechanism in mice with myocardial infarction (MI). We used left anterior coronary artery descending ligation to develop an MI model for in vivo analyses. In contrast, H9C2 cells and cardiac fibroblasts were used to establish the oxygen-glucose deprivation (OGD) model in in vitro analyses. In vivo and in vitro models were treated with Klotho. Compound C, an AMPK signaling inhibitor, was used to determine whether Klotho's effects are mediated through the AMPK/mTOR signaling pathway. Echocardiography, Masson trichrome staining, immunofluorescence, immunohistochemistry, real-time polymerase chain reaction (RT-PCR), and western blot were used to detect the related indicators. The findings of the in vivo model indicate that Klotho treatment improved the mice's cardiac function, reduced cardiac fibrosis, and attenuated myocardial inflammatory factors, ferroptosis, and oxidative stress. The results of the in vitro model were in line with the findings of in vivo modeling. An AMPK inhibitor, Compound C, reversed all these effects. In conclusion, Klotho potentially improves cardiac remodeling in MI mice by regulating AMPK/mTOR signaling, demonstrating Klotho as an effective MI therapeutic agent.

Noncanonical JAK1/STAT3 interactions with TGF-β modulate myofibroblast transdifferentiation and fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with limited survival. Janus kinases (JAKs), tyrosine kinases that transduce cytokine-mediated signals, are known to be involved, but their specific roles in lung fibrosis are not well defined. In this study, the interactions between JAK1/signal transducers and activators of transcription (STAT)3 signaling and transforming growth factor-beta (TGF-β)-induced fibroblast responses were investigated using both pharmacological and siRNA approaches in human normal and IPF-derived lung fibroblasts. We found that JAK1 directly interacts with the TGF-β receptor I subunit (TβRI), and silencing JAK1 promotes myofibroblast transdifferentiation. However, the suppression of JAK1 signaling in vitro and in vivo using an inhibitor (upadacitinib) did not alter lung fibroblast activation or fibrosis development. STAT3 was constitutively active in cultured primary lung fibroblasts; this STAT3 activation required JAK1 and repressed myofibroblast transdifferentiation. Loss of phosphorylated STAT3 following transcriptional JAK1 silencing promoted myofibroblast transdifferentiation. In contrast, transcriptional silencing of unphosphorylated STAT3 suppressed TGF-β signaling, decreased SMAD3 activation, and reduced myofibroblast transdifferentiation and ECM production. Taken together, these observations support a role for JAK1/STAT3 as a direct regulator of TGF-β signaling in lung fibroblasts. Modulation of JAK1/STAT3 signaling in lung fibroblasts represents a noncanonical approach to regulating TGF-β-induced fibrosis and suggests the potential for a novel approach to treat pulmonary fibrosis.

An optimized herbal combination for the treatment of liver fibrosis: Hub genes, bioactive ingredients, and molecular mechanisms

ETHNOPHARMACOLOGICAL RELEVANCE

Liver fibrosis is a chronic liver disease that can lead to cirrhosis, liver failure, and hepatocellular carcinoma, and it is associated with long-term adverse outcomes and mortality. As a primary resource for complementary and alternative medicine, traditional Chinese medicine (TCM) has accumulated a large number of effective formulas for the treatment of liver fibrosis in clinical practice. However, studies on how to systematically optimize TCM formulas are still lacking.

AIM OF THE REVIEW

To provide a methodological reference for the systematic optimization of TCM formulae against liver fibrosis and explored the underlying molecular mechanisms; To provide an efficient method for searching for lead compounds from natural sources and developing from herbal medicines; To enable clinicians and patients to make more reasonable choices and promote the effective treatment toward those patients with liver fibrosis.

MATERIALS AND METHODS

TCM formulas related to treating liver fibrosis were collected from the Web of Science, PubMed, the China National Knowledge Infrastructure (CNKI), Wan Fang, and the Chinese Scientific Journals Database (VIP). Furthermore, the TCM compatibility patterns were mined using association analysis. The core TCM combinations were found by designing an optimized formulas algorithm. Finally, the hub target proteins, potential molecular mechanisms, and active compounds were explored through integrative pharmacology and docking-based inverse virtual screening (IVS) approaches.

RESULTS

We found that the herbs for reinforcing deficiency, activating blood, removing blood stasis, and clearing heat were the basis of TCM formulae patterns. Furthermore, the combination of Salviae Miltiorrhizae (Salvia miltiorrhiza Bunge; Chinese salvia/Danshen), Astragali Radix (Astragalus membranaceus (Fisch.) Bunge; Astragalus/Huangqi), and Radix Bupleuri (Bupleurum chinense DC.; Bupleurum/Chaihu) was identified as core groups. A total of six targets (TNF, STAT3, EGFR, IL2, ICAM1, PTGS2) play a pivotal role in TCM-mediated liver fibrosis inhibition. (-)-Cryptotanshinone, Tanshinaldehyde, Ononin, Thymol, Daidzein, and Formononetin were identified as active compounds in TCM. And mechanistically, TCM could affect the development of liver fibrosis by regulating inflammation, immunity, angiogenesis, antioxidants, and involvement in TNF, MicroRNAs, Jak-STAT, NF-kappa B, and C-type lectin receptors (CLRs) signaling pathways. Molecular docking results showed that key components had good potential to bind to the target genes.

CONCLUSION

In summary, this study provides a methodological reference for the systematic optimization of TCM formulae and exploration of underlying molecular mechanisms.

Established new compound IMB16-4 self-emulsifying drug delivery systems for increasing oral bioavailability and enhancing anti-hepatic fibrosis effect

Liver fibrosis results from the chronic liver injury and no specific medical therapy is approved so far. Recently, new compound, N-(3,4,5-trichlorophenyl) - 2 (3-nitrobenzenesulfonamido) benzamide, referred to as IMB16-4, was developed to resist liver fibrosis. However, IMB16-4 displays poor aqueous solubility and poor oral bioavailability. To increase the dissolution rate, improve the oral bioavailability and enhance the anti-hepatic fibrosis action of IMB16-4, IMB16-4 self-emulsifying drug delivery systems (SEDDS) with negative charge or positive charge were prepared using simple stirring, respectively. Their stability, oral bioavailability and anti-liver fibrosis effect were evaluated. The results showed IMB16-4 SEDDS in simulated gastric juice were nearly spherical with the diameter of 100～200 nm and possessed good stability in 30 days. The oral bioavailability of IMB16-4 SEDDS with negative charge and positive charge were increased to 33 folds and 58 folds compared with that of pure IMB16-4, respectively. In bile duct ligation (BDL) rats, IMB16-4 SEDDS attenuated the degree of liver damage and decreased collagen accumulation. In addition, IMB16-4 SEDDS with negative charge easily accumulated in the liver and alleviated hepatic fibrosis by TGF-β/Smad signaling. These findings indicate that IMB16- 4 SEDDS may be a potential therapy for the treatment of liver fibrosis.

Tanshinone IIA regulates the TGF‑β1/Smad signaling pathway to ameliorate non‑alcoholic steatohepatitis‑related fibrosis

Tanshinone IIA (TIIA) is a major component extracted from the traditional herbal medicine Salvia miltiorrhiza and has been indicated to play a role in the treatment of organ fibrosis. However, the evidence supporting its antifibrotic effect is insufficient and the underlying mechanism is unclear. To investigate the therapeutic effect of TIIA on non-alcoholic steatohepatitis-related fibrosis (NASH-F), the present study used a methionine choline deficiency diet to induce NASH-F in rats, and explored the effect of TIIA on the transforming growth factor-β1 (TGF-β1)/Smad signaling pathway. Wistar rats were randomly divided into control, NASH-F and TIIA groups. After 8 weeks of treatment, the levels of serum markers associated with liver function and fibrosis were measured, liver fat vacuoles and inflammation were assessed by haematoxylin and eosin staining, and liver fibrosis was assessed by Masson's trichrome staining. TGF-β1, Smad2, Smad3, Smad7 and α-smooth muscle actin (α-SMA) mRNA expression, and TGF-β1, Smad2/3, phosphorylated (p)-Smad2/3, Smad7 and α-SMA protein levels were determined. The results revealed that TIIA could remarkably ameliorate liver fat vacuoles and inflammation in NASH-F rats, and could decrease the levels of serum aspartate aminotransferase, alanine aminotransferase, total bilirubin, total bile acid, hyaluronic acid, type Ⅳ collagen, laminin and type III collagen, while increasing the levels of total cholesterol and triglycerides; however, this was not statistically significance. TIIA markedly suppressed the increased TGF-β1, Smad2, Smad3 and α-SMA mRNA expression levels observed in the liver of NASH-F rats, while it increased the mRNA expression level of Smad7. Similarly, TIIA suppressed the increased TGF-β1, p-Smad2/3 and α-SMA protein levels observed in the liver of NASH-F rats, while it increased the protein expression level of Smad7 in vitro and in vivo. TIIA had no significant cytotoxic effect at 10, 20, 40 and 80 µmol/l on human LX-2 cell. In conclusion, the findings of the present study indicated that TIIA alleviated NASH-F by regulating the TGF-β1/Smad signaling pathway. TIIA may be a useful tool in the prevention and treatment of NASH-F.

Upregulation of cadherin‐11 contributes to cholestatic liver fibrosis

Importance

Cadherin‐11 (CDH11), a cell‐to‐cell adhesion molecule, is implicated in the fibrotic process of several organs. Biliary atresia (BA) is a common cholestatic liver disease featuring cholestasis and progressive liver fibrosis in children. Cholestatic liver fibrosis may progress to liver cirrhosis and lacks effective therapeutic strategies. Currently, the role of CDH11 in cholestatic liver fibrosis remains unclear.

Objective

This study aimed to explore the functions of CDH11 in cholestatic liver fibrosis.

Methods

The expression of CDH11 in BA livers was evaluated by database analysis and immunostaining. Seven BA liver samples were used for immunostaining. The wild type (Wt) and CDH11 knockout (CDH11^–/–) mice were subjected to bile duct ligation (BDL) to induce cholestatic liver fibrosis. The serum biochemical analysis, liver histology, and western blotting were used to assess the extent of liver injury and fibrosis as well as activation of transforming growth factor‐β (TGF‐β)/Smad pathway. The effect of CDH11 on the activation of hepatic stellate cell line LX‐2 cells was investigated.

Results

Analysis of public RNA‐seq datasets showed that CDH11 expression levels were significantly increased in livers of BA, and CDH11 was correlated with liver fibrosis in BA. BDL‐induced liver injury and liver fibrosis were attenuated in CDH11^–/– mice compared to Wt mice. The protein expression levels of phosphorylated Smad2/3 were decreased in livers of CDH11^–/– BDL mice compared to Wt BDL mice. CDH11 knockdown inhibited the activation of LX‐2 cells.

Interpretation

CDH11 plays an important role in cholestatic liver fibrosis and may represent a potential therapeutic target for cholestatic liver disease, such as BA.

Histopathology, matrix metalloproteinase-2 and alpha smooth muscle actin expression in Tenon's capsule of eyes with congenital glaucoma

PURPOSE

To evaluate the ultrastructural features of collagen fibrils, matrix metalloproteinase (MMP) and alpha-smooth muscle actin (α-SMA) expression in the Tenon's capsule of buphthalmic eyes.

METHODS

A prospective comparative case series study was conducted on 35 buphthalmic eyes vs 25 control eyes. Children with congenital glaucoma (CG) who underwent a combined trabeculectomy-trabeculotomy procedure with mitomycin C (CTTM); the Tenon's capsule was obtained during the surgical procedure. The control group included children with strabismus, the Tenon's capsule was obtained in the course of strabismus surgery. Both H&E and Masson's trichrome staining were done. The Metalloprotenease-2 (MMP-2), alpha smooth muscle actin (α-SMA) immunohistochemical staining was performed.

RESULTS

Mean collagen percentage area by Masson trichrome stain in Tenons capsule was significantly higher in buphthalmic eyes (54.76% ± 0.32 vs 33.71% ± 1.4; P < 0.001).The percentage area of αSMA expression in Tenons capsule was significantly higher in buphthalmic eyes (4.93% ± 0.7 vs 2.00% ± 0.5; P < 0.001). However, MMP2 expression in Tenons capsule of the buphthalmic group was significantly lower than that of the control group (12.88% ± 2.95 vs 27.91% ± 0.2 respectively) P = 0.02.

CONCLUSIONS

Tenon capsule of buphthalmic eyes have their own histopathological features and properties making them more liable for fibrosis with high rate of failure following antiglaucoma surgeries. Such detailed information has not been published before which may aid in the identification of new antifibrotic therapies in management of glaucoma.

Fedratinib Attenuates Bleomycin-Induced Pulmonary Fibrosis via the JAK2/STAT3 and TGF-β1 Signaling Pathway

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive interstitial lung disease with multiple causes, characterized by excessive myofibrocyte aggregation and extracellular matrix deposition. Related studies have shown that transforming growth factor-β1 (TGF-β1) is a key cytokine causing fibrosis, promoting abnormal epithelial-mesenchymal communication and fibroblast-to-myofibroblast transition. Fedratinib (Fed) is a marketed drug for the treatment of primary and secondary myelofibrosis, targeting selective JAK2 tyrosine kinase inhibitors. However, its role in pulmonary fibrosis remains unclear. In this study, we investigated the potential effects and mechanisms of Fed on pulmonary fibrosis in vitro and in vivo. In vitro studies have shown that Fed attenuates TGF-β1- and IL-6-induced myofibroblast activation and inflammatory response by regulating the JAK2/STAT3 signaling pathway. In vivo studies have shown that Fed can reduce bleomycin-induced inflammation and collagen deposition and improve lung function. In conclusion, Fed inhibited inflammation and fibrosis processes induced by TGF-β1 and IL-6 by targeting the JAK2 receptor.

Tiaoshen Tongluo Attenuates Fibrosis by Modulating the TGF-β1/Smad Pathway in Endometrial Stromal Cells and a Rat Model of Intrauterine Adhesion

Intrauterine adhesion (IUA) is a serious complication caused by excessive fibrosis resulting from endometrial repair after trauma. The traditional Chinese medicine Tiaoshen Tongluo recipe (TTR) contains ingredients associated with the alleviation of fibrosis. The transforming growth factor-β1 (TGF-β1)/Smad pathway is thought to mediate fibrosis in IUA. In this study, we evaluated the influence of TTR on endometrial fibrosis in a rat model of IUA and in TGF-β1-stimulated endometrial stromal cells (ESCs). TTR was found to alleviate the level of endometrial fibrosis in a rat model of IUA. A higher number of collagen fibers and greater damage were observed in the endometrial tissue of untreated rats compared to those treated with TTR. The expression of TGF-β1, Smad2, Smad3, and Smad4 was upregulated following IUA, whereas Smad7 expression was downregulated. TTR lowers the expression of TGF-β1, Smad2, Smad3, and Smad4 but increases the expression of Smad7 in vivo, indicating that TTR can modulate the expression of the TGF-β1/Smad pathway to mediate fibrosis. In ESCs, the phosphorylation of Smad2 and Smad3 and upregulation of Smad4 were induced by TGF-β1 whereas the expression of Smad7 was inhibited. Administration of TTR reduces the phosphorylation of Smad2 and Smad3, increases Smad4 expression induced by TGF-β1, and promotes the expression of Smad7. TTR modulates the TGF-β1/Smad pathway to alleviate the generation of fibrotic tissue in response to IUA.

Apigenin Alleviates Liver Fibrosis by Inhibiting Hepatic Stellate Cell Activation and Autophagy via TGF-β1/Smad3 and p38/PPARα Pathways

Objective

The aim of this study is to confirm the hepatocellular protective functions of apigenin and the molecular mechanism on liver fibrosis in mice.

Methods

Carbon tetrachloride (CCl₄) and bile duct ligature (BDL) mouse fibrosis models were used to investigate the effects of apigenin on liver fibrosis. Sixty-six male C57 mice were randomly divided into eight groups, including the vehicle group, CCl₄ group, CCl₄+L-apigenin (20 mg/kg) group, CCl₄+H-apigenin (40 mg/kg) group, sham group, BDL group, BDL+L-apigenin(20 mg/kg) group, and BDL+H-apigenin(40 mg/kg) group. Serum liver enzymes (ALT and AST), proteins associated with autophagy, and indicators linked with the TGF-β1/Smad3 and p38/PPARα pathways were detected using qRT-PCR, immunohistochemical staining, and western blotting.

Results

Our findings confirmed that apigenin could decrease the levels of ALT and AST, suppress the generation of ECM, inhibit the activation of HSCs, regulate the balance of MMP2 and TIMP1, reduce the expression of autophagy-linked protein, and restrain the TGF-β1/Smad3 and p38/PPARα pathways.

Conclusion

Apigenin could alleviate liver fibrosis by inhibiting hepatic stellate cell activation and autophagy via TGF-β1/Smad3 and p38/PPARα pathways.

PPARγ/NF-κB and TGF-β1/Smad pathway are involved in the anti-fibrotic effects of levo-tetrahydropalmatine on liver fibrosis

Liver fibrosis is a necessary stage in the development of chronic liver diseases to liver cirrhosis. This study aims to investigate the anti‐fibrotic effects of levo‐tetrahydropalmatine (L‐THP) on hepatic fibrosis in mice and cell models and its underlying mechanisms. Two mouse hepatic fibrosis models were generated in male C57 mice by intraperitoneal injection of carbon tetrachloride (CCl4) for 2 months and bile duct ligation (BDL) for 14 days. Levo‐tetrahydropalmatine was administered orally at doses of 20 and 40 mg/kg. An activated LX2 cell model induced by TGF‐β1 was also generated. The results showed that levo‐tetrahydropalmatine alleviated liver fibrosis by inhibiting the formation of extracellular matrix (ECM) and regulating the balance between TIMP1 and MMP2 in the two mice liver fibrosis models and cell model. Levo‐tetrahydropalmatine inhibited activation and autophagy of hepatic stellate cells (HSCs) by modulating PPARγ/NF‐κB and TGF‐β1/Smad pathway in vivo and in vitro. In conclusion, levo‐tetrahydropalmatine attenuated liver fibrosis by inhibiting ECM deposition and HSCs autophagy via modulation of PPARγ/NF‐κB and TGF‐β1/Smad pathway.

Depletion of serotonin relieves concanavalin A-induced liver fibrosis in mice by inhibiting inflammation, oxidative stress, and TGF-β1/Smads signaling pathway

Serotonin exerts important functions in several liver pathophysiological processes. In this study, we investigated the role of serotonin in concanavalin A (Con A)-induced liver fibrosis (LF) in mice and the underlying mechanisms. To establish the mouse model of LF, mice of wild-type (WT) and tryptophan hydroxylase 1 (Tph1) knockout (serotonin depletion) received Con A for 8 successive weeks. Degree of fibrosis was assessed by Sirius red staining, as well as the measurements of alpha smooth muscle actin (α- SMA), hydroxyproline (Hyp) and type I collagen in liver tissues. To elucidate the potential mechanisms, we assessed the effect of serotonin depletion on inflammatory, oxidative stress as well as TGF-β1/Smads signaling pathway. We found that serotonin depletion significantly inhibited collagen deposition as evaluated by less collagenous fiber in Sirus Red staining and reduced contents of Hyp and type I collagen. In addition, the absence of serotonin significantly inhibited the release of several inflammatory cytokines, including interleukin-6 (IL-6), interferon-gamma (IFN-γ), tumor necrosis-alpha (TNF-α), and transforming growth factor β1 (TGF-β1). Oxidative stress was also largely mitigated in LF mice with serotonin deficiency as manifested by the decreases of oxidative stress markers (malonaldehyde (MDA) and myeloperoxidase (MPO)), as well as the increases of antioxidant stress indicators (glutathione (GSH), and GSH-px, catalase (CAT), superoxide dismutase (SOD)) in liver tissues. Moreover, the lack of serotonin may provide an antifibrotic role by inhibiting the intrahepatic expressions of TGF-β1, phosphorylated-smad2 (p-smad2), and phosphorylated-smad3 (p-smad3). These results indicated that, serotonin depletion attenuates Con A-induced LF through the regulation of inflammatory response, oxidative stress injury, and TGF-β1/Smads signaling pathway.

TGFβ acts through PDGFRβ to activate mTORC1 via the Akt/PRAS40 axis and causes glomerular mesangial cell hypertrophy and matrix protein expression

Interaction of transforming growth factor-β (TGFβ)-induced canonical signaling with the noncanonical kinase cascades regulates glomerular hypertrophy and matrix protein deposition, which are early features of glomerulosclerosis. However, the specific target downstream of the TGFβ receptor involved in the noncanonical signaling is unknown. Here, we show that TGFβ increased the catalytic loop phosphorylation of platelet-derived growth factor receptor β (PDGFRβ), a receptor tyrosine kinase expressed abundantly in glomerular mesangial cells. TGFβ increased phosphorylation of the PI 3-kinase-interacting Tyr-751 residue of PDGFRβ, thus activating Akt. Inhibition of PDGFRβ using a pharmacological inhibitor and siRNAs blocked TGFβ-stimulated phosphorylation of proline-rich Akt substrate of 40 kDa (PRAS40), an intrinsic inhibitory component of mTORC1, and prevented activation of mTORC1 in the absence of any effect on Smad 2/3 phosphorylation. Expression of constitutively active myristoylated Akt reversed the siPDGFRβ-mediated inhibition of mTORC1 activity; however, co-expression of the phospho-deficient mutant of PRAS40 inhibited the effect of myristoylated Akt, suggesting a definitive role of PRAS40 phosphorylation in mTORC1 activation downstream of PDGFRβ in mesangial cells. Additionally, we demonstrate that PDGFRβ-initiated phosphorylation of PRAS40 is required for TGFβ-induced mesangial cell hypertrophy and fibronectin and collagen I (α2) production. Increased activating phosphorylation of PDGFRβ is also associated with enhanced TGFβ expression and mTORC1 activation in the kidney cortex and glomeruli of diabetic mice and rats, respectively. Thus, pursuing TGFβ noncanonical signaling, we identified how TGFβ receptor I achieves mTORC1 activation through PDGFRβ-mediated Akt/PRAS40 phosphorylation to spur mesangial cell hypertrophy and matrix protein accumulation. These findings provide support for targeting PDGFRβ in TGFβ-driven renal fibrosis.

The Roles of Immune Cells in the Pathogenesis of Fibrosis

Tissue injury and inflammatory response trigger the development of fibrosis in various diseases. It has been recognized that both innate and adaptive immune cells are important players with multifaceted functions in fibrogenesis. The activated immune cells produce various cytokines, modulate the differentiation and functions of myofibroblasts via diverse molecular mechanisms, and regulate fibrotic development. The immune cells exhibit differential functions during different stages of fibrotic diseases. In this review, we summarized recent advances in understanding the roles of immune cells in regulating fibrotic development and immune-based therapies in different disorders and discuss the underlying molecular mechanisms with a focus on mTOR and JAK-STAT signaling pathways.

TGF-β/Smad and JAK/STAT pathways are involved in the anti-fibrotic effects of propylene glycol alginate sodium sulphate on hepatic fibrosis

Liver fibrosis, a consequence of unhealthy modern lifestyles, has a growing impact on human health, particularly in developed countries. Here, we have explored the anti‐fibrotic effects of propylene glycol alginate sodium sulphate (PSS), a natural extract from brown algae, in fibrotic mice and cell models. Thus, we established bile duct ligature and carbon tetrachloride mouse models and LX‐2 cell models with or without PSS treatment. Liver pathological sections and the relevant indicators in serum and liver tissues were examined. PSS prevented hepatic injury and fibrosis to a significant extent, and induced up‐regulation of matrix metalloproteinase‐2 and down‐regulation of tissue inhibitor of metalloproteinase‐1 through suppressing the transforming growth factor β1 (TGF‐β1)/Smad pathway. PSS additionally exerted an anti‐autophagy effect through suppressing the Janus kinase (JAK) 2/transducer and activator of transcription 3 (STAT3) pathway. In conclusion, PSS prevents hepatic fibrosis by suppressing inflammation, promoting extracellular matrix (ECM) decomposition and inactivating hepatic stellate cells through mechanisms involving the TGF‐β1/Smad2/3 and JAK2/STAT3 pathways in vivo and in vitro.