The PIEZO1/miR-155-5p/GDF6/SMAD2/3 signaling axis is involved in inducing the occurrence and progression of osteoarthritis under excessive mechanical stress

OBJECTIVE

To elucidate the molecular mechanism of overloading-induced osteoarthritis (OA) and to find a novel therapeutic target.

METHODS

We utilized human cartilage specimens, mouse chondrocytes, a destabilization of the medial meniscus (DMM) mouse model, and a mouse hindlimb weight-bearing model to validate the role of overloading on chondrocyte senescence and OA development. Then, we observed the effect of PIEZO1-miR-155-5p-GDF6-SMAD2/3 signaling axis on the preservation of joint metabolic homeostasis under overloading in vivo, in vitro and ex vivo by qPCR, Western blot, enzyme-linked immunosorbent assay (ELISA), immunohistochemistry, immunofluorescence, SA-β-gal staining, CCK8 assay, et al. Finally, we verified the therapeutic effects of intra-articular injection of miR-155-5p inhibitor or recombinant GDF6 on the murine overloading-induced OA models.

RESULTS

Chondrocytes sensesed the mechanical overloading through PIEZO1 and up-regulated miR-155-5p expression. MiR-155-5p mimics could copy the effects of overloading-induced chondrocyte senescence and OA. Additionally, miR-155-5p could suppress the mRNA expression of Gdf6-Smad2/3 in various tissues within the joint. Overloading could disrupt joint metabolic homeostasis by downregulating the expression of anabolism indicators and upregulating the expression of catabolism indicators in the chondrocytes and synoviocytes, while miR-155-5p inhibition or GDF6 supplementation could exert an antagonistic effect by preserving the joint homeostasis. Finally, in the in vivo overloading models, intra-articular injection of miR-155-5p inhibitor or recombinant GDF6 could significantly mitigate the severity of impending OA and lessened the progression of existing OA.

CONCLUSION

GDF6 overexpression or miR-155-5p inhibition could attenuate overloading-induced chondrocyte senescence and OA through the PIEZO1-miR-155-5p-GDF6-SMAD2/3 signaling pathway. Our study provides a new therapeutic target for the treatment of overloading-induced OA.

TMED3 stabilizes SMAD2 by counteracting NEDD4-mediated ubiquitination to promote ovarian cancer

Ovarian cancer is a major cause of death among cancer patients. Recent research has shown that the transmembrane emp24 domain (TMED) protein family plays a role in the progression of various types of cancer. In this study, we investigated the expression of TMED3 in ovarian cancer tumors compared to nontumor tissues using immunohistochemical staining. We found that TMED3 was overexpressed in ovarian cancer tumors, and its high expression was associated with poor disease-free and overall survival. To understand the functional implications of TMED3 overexpression in ovarian cancer, we conducted experiments to knockdown TMED3 using short hairpin RNA (shRNA). We observed that TMED3 knockdown resulted in reduced cell viability and migration, as well as increased cell apoptosis. Additionally, in subcutaneous xenograft models in BALB-c nude mice, TMED3 knockdown inhibited tumor growth. Further investigation revealed that SMAD family member 2 (SMAD2) was a downstream target of TMED3, driving ovarian cancer progression. TMED3 stabilized SMAD2 by inhibiting the E3 ligase NEDD4-mediated ubiquitination of SMAD2. To confirm the importance of SMAD2 in TMED3-mediated ovarian cancer, we performed functional rescue experiments and found that SMAD2 played a critical role in this process. Moreover, we discovered that the PI3K-AKT pathway was involved in the promoting effects of TMED3 overexpression on ovarian cancer cells. Overall, our study identifies TMED3 as a prognostic indicator and tumor promoter in ovarian cancer. Its function is likely mediated through the regulation of the SMAD2 and PI3K-AKT signaling pathway. These findings contribute to our understanding of the molecular mechanisms underlying ovarian cancer progression and provide potential targets for therapeutic intervention.

Adipocyte-derived exosomes from obstructive sleep apnoea rats aggravate MASLD by TCONS_00039830/miR-455-3p/Smad2 axis

A correlation exists between obstructive sleep apnoea (OSA) and the severity of metabolic dysfunction-associated steatotic liver disease (MASLD), OSA can induce more severe MASLD. However, the underlying regulatory mechanism between the two is unclear. To this end, this study explored the role and possible molecular mechanisms of adipocyte-derived exosomes under OSA in aggravating MASLD. Through sequencing technology, miR-455-3p was identified as a co-differentially expressed miRNA between the MASLD + OSA and Control groups and between the MASLD + OSA and MASLD groups. Upregulation of TCONS-00039830 and Smad2 and downregulation of miR-455-3p in the MASLD and MASLD + OSA groups were validated in vivo and in vitro. TCONS-00039830, as a differentially expressed LncRNA in exosomes found in the sequencing results, transfection notably downregulated miR-455-3p and upregulated Smad2 in hepatocytes. TCONS_00039830 overexpression increased fat, triglyceride and cholesterol levels, while miR-455-3p overexpression decreased these levels. Furthermore, exosome administration promoted the accumulation of fat, triglyceride and cholesterol, upregulated TCONS_00039830 and Smad2, and downregulated miR-455-3p. Overexpression of miR-455-3p reversed the increased fat accumulation and upregulated TCONS_00039830 and Smad2. In conclusion, OSA-derived exosomes promoted hepatocyte steatosis by regulating TCONS_00039830/miR-455-3p/Smad2 axis, thereby aggravating liver damage in MASLD.

Stigmasterol alleviates airway inflammation in OVA-induced asthmatic mice via inhibiting the TGF-β1/Smad2 and IL-17A signaling pathways

Stigmasterol is a common dietary phytosterol with high nutritional value and physiological activity. In this study, we evaluated the effects of stigmasterol on inflammatory cytokines and the TGF-β1/Smad2 and IL-17A signaling pathway in an ovalbumin (OVA)-induced asthma mouse model. Stigmasterol treatment improved airway remodeling. In addition, it significantly attenuated the symptoms of asthma attacks, reduced the number of macrophages, lymphocytes, neutrophils, and eosinophils in BALF and inflammatory cytokines, including IL-1β, IL-5, IL-6, and IL-13. It further decreased the level of IL-17A in BALF, serum and spleen. Spleen single-cell suspension analysis via flow cytometry showed that IL-17A level was consistent with the results obtained in BALF, serum and spleen. Stigmasterol decreased the protein expression levels of TGF-β, p-Smad2 and IL-17A in the spleen, by increasing the protein expression level of IL-10. After 24 h of co-culture of TGF-β, IL-6 and stigmasterol, the level of IL-17 in CD4+ T cell supernatant was lower relative to levels in the group without stigmasterol. Meanwhile, stigmasterol treatment attenuated the expression level of TGF- β, p-Smad2 and IL-17A proteins in CD4+ T cells and enhanced the expression levels of IL-10 protein. These data suggested that stigmasterol inhibited the TGF-β1/Smad2 and IL-17A signaling pathway to achieve anti-asthmatic effects in the OVA-induced asthma mouse model. Collectively, the results of this study are that stigmasterol has achieved preliminary efficacy in the non-clinical laboratory, further studies are needed to consider the clinical application of stigmasterol.

Gulp1 regulates chondrocyte growth arrest and differentiation via the TGF-β/SMAD2/3 pathway

Chondrocyte differentiation is crucial for cartilage formation. However, the complex processes and mechanisms coordinating chondrocyte proliferation and differentiation remain incompletely understood. Here, we report a novel function of the adaptor protein Gulp1 in chondrocyte differentiation. Gulp1 expression is upregulated during chondrogenic differentiation. Gulp1 knockdown in chondrogenic ATDC5 cells reduces the expression of chondrogenic and hypertrophic marker genes during differentiation. Furthermore, Gulp1 knockdown impairs cell growth arrest during chondrocyte differentiation and reduces the expression of the cyclin-dependent kinase inhibitor p21. The activation of the TGF-β/SMAD2/3 pathway, which is associated with p21 expression in chondrocytes, is impaired in Gulp1 knockdown cells. Collectively, these results demonstrate that Gulp1 contributes to cell growth arrest and chondrocyte differentiation by modulating the TGF-β/SMAD2/3 pathway.

The immune regulation and therapeutic potential of the SMAD gene family in breast cancer

Breast cancer is a serious threat to human health. The transforming growth factor-β signaling pathway is an important pathway involved in the occurrence and development of cancer. The SMAD family genes are responsible for the TGF-β signaling pathway. However, the mechanism by which genes of the SMAD family are involved in breast cancer is still unclear. Therefore, it is necessary to investigate the biological roles of the SMAD family genes in breast cancer. We downloaded the gene expression data, gene mutation data, and clinical pathological data of breast cancer patients from the UCSC Xena database. We used the Wilcox test to estimate the expression of genes of the SMAD family in cancers. And the biological functions of SMAD family genes using the DAVID website. The Pearson correlation method was used to explore the immune cell infiltration and drug response of SMAD family genes. We conducted in biological experiments vitro and vivo. In this study, we integrated the multi-omics data from TCGA breast cancer patients for analysis. The expression of genes of SMAD family was significantly dysregulated in patients with breast cancer. Except for SMAD6, the expression of other SMAD family genes was positively correlated. We also found that genes of the SMAD family were significantly enriched in the TGF-β signaling pathway, Hippo signaling pathway, cell cycle, and cancer-related pathways. In addition, SMAD3, SMAD6, and SMAD7 were lowly expressed in stage II breast cancer, while SMAD4 and SMAD2 were lowly expressed in stage III cancer. Furthermore, the expression of genes of the SMAD family was significantly correlated with immune cell infiltration scores. Constructing a xenograft tumor mouse model, we found that SMAD3 knockdown significantly inhibited tumorigenesis. Finally, we analyzed the association between these genes and the IC50 value of drugs. Interestingly, patients with high expression of SMAD3 exhibited significant resistance to dasatinib and staurosporine, while high sensitivity to tamoxifen and auranofin. In addition, SMAD3 knockdown promoted the apoptosis of BT-549 cells and decreased cell activity, and BAY-1161909 and XK-469 increased drug efficacy. In conclusion, genes of the SMAD family play a crucial role in the development of breast cancer.

Prodigiosin Inhibits Transforming Growth Factor β Signaling by Interfering Receptor Recycling and Subcellular Translocation in Epithelial Cells

Prodigiosin (PG) is a naturally occurring polypyrrole red pigment produced by numerous microorganisms including some Serratia and Streptomyces strains. PG has exhibited promising anticancer activity; however, the molecular mechanisms of action of PG on malignant cells remain ambiguous. Transforming growth factor-β (TGF-β) is a multifunctional cytokine that governs a wide array of cellular processes in development and tissue homeostasis. Malfunctions of TGF-β signaling are associated with numerous human cancers. Emerging evidence underscores the significance of internalized TGF-β receptors and their intracellular trafficking in initiating signaling cascades. In this study, we identified PG as a potent inhibitor of the TGF-β pathway. PG blocked TGF-β signaling by targeting multiple sites of this pathway, including facilitating the sequestering of TGF-β receptors in the cytoplasm by impeding the recycling of type II TGF-β receptors to the cell surface. Additionally, PG prompts a reduction in the abundance of receptors on the cell surface through the disruption of the receptor glycosylation. In human Caucasian lung carcinoma cells and human hepatocellular cancer cell line cells, nanomolar concentrations of PG substantially diminish TGF-β-triggered phosphorylation of Smad2 protein. This attenuation is further reflected in the suppression of downstream target gene expression, including those encoding fibronectin, plasminogen activator inhibitor-1, and N-cadherin. SIGNIFICANCE STATEMENT: Prodigiosin (PG) emerges from this study as a potent TGF-β pathway inhibitor, disrupting receptor trafficking and glycosylation and reducing TGF-β signaling and downstream gene expression. These findings not only shed light on PG's potential therapeutic role but also present a captivating avenue towards future anti-TGF-β strategies.

Knockdown of the UL-16 binding protein 1 promotes osteoblast differentiation of human mesenchymal stem cells by activating the SMAD2/3 pathway

Osteoporosis is caused by the imbalance of osteoblasts and osteoclasts. The regulatory mechanisms of differentially expressed genes (DEGs) in pathogenesis of osteoporosis are of significant and needed to be further investigated. GSE100609 dataset downloaded from Gene Expression Omnibus (GEO) database was used to identified DEGs in osteoporosis patients. KEGG analysis was conducted to demonstrate signaling pathways related to enriched genes. Osteoporosis patients and the human mesenchymal stem cells (hMSCs) were obtained for in vivo and in vitro resaerch. Lentivirus construction and viral infection was used to knockdown genes. mRNA expression and protein expression were detected via qRT-PCR and western blot assay separately. Alkaline phosphatase (ALP) activity detection, alizarin Red S (ARS) staining, and expression of bone morphogenetic protein 2 (BMP2), osteocalcin (OCN) and Osterix were evaluated to determine osteoblast differentiation capacity. UL-16 binding protein 1 (ULBP1) gene was upregulated in osteoporosis and downregulated in differentiated hMSCs. Knockdown of ULBP1 increased ALP activity, mineralization ability evaluated by ARS staining, expression of BMP2, OCN and Osterix in differentiated hMSCs. Furthermore, rescue experiment demonstrated that suppressed ULBP1 boosted osteoblast differentiation by activating TNF-β signaling pathway. Knockdown of ULBP1 gene could promoted osteoblast differentiation by activating TNF-β signaling pathway in differentiated hMSCs. ULBP1 may be a the Achilles' heel of osteoporosis, and suppression of ULBP1 could be a promising treatment for osteoporosis.

Icariin Regulates EMT and Stem Cell-Like Character in Breast Cancer through Modulating lncRNA NEAT1/TGFβ/SMAD2 Signaling Pathway

Metastases and drug resistance are the major risk factors associated with breast cancer (BC), which is the most common type of tumor affecting females. Icariin (ICA) is a traditional Chinese medicine compound that possesses significant anticancer properties. Long non-coding RNAs (lncRNAs) are involved in a wide variety of biological and pathological processes and have been shown to modulate the effectiveness of certain drugs in cancer. The purpose of this study was to examine the potential effect of ICA on epithelial mesenchymal transition (EMT) and stemness articulation in BC cells, as well as the possible relationship between its inhibitory action on EMT and stemness with the NEAT1/transforming growth factor β (TGFβ)/SMAD2 pathway. The effect of ICA on the proliferation (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and colony assays), EMT (Western blotting, immunofluorescence, and wound healing), and stemness (mammosphere formation assays, Western blotting) of BC cells were examined. According to the findings, ICA suppressed the proliferation, EMT, and stem cell-like in MDA-MB-231 cells, and exerted its inhibitory impact by downregulating the TGFβ/SMAD2 signaling pathway. ICA could significantly downregulate the expression of lncRNA NEAT1, and silencing NEAT1 enhanced the effect of ICA in suppressing EMT and expression of different stem cell markers. In addition, silencing NEAT1 was found to attenuate the TGFβ/SMAD2 signaling pathway, thereby improving the inhibitory impact of ICA on stemness and EMT in BC cells. In conclusion, ICA can potentially inhibit the metastasis of BC via affecting the NEAT1/TGFβ/SMAD2 pathway, which provides a theoretical foundation for understanding the mechanisms involved in potential application of ICA for BC therapy.

MET exon 14 skipping mutation drives cancer progression and recurrence via activation of SMAD2 signalling

BACKGROUND

c-Met encoded by the proto-oncogene MET, also known as hepatocyte growth factor (HGF) receptor, plays a crucial role in cellular processes. MET exon 14 skipping alteration (METΔ14EX) is a newly discovered MET mutation. SMAD2 is an important downstream transcription factor in TGF-β pathway. Unfortunately, the mechanisms by which METΔ14EX leads to oncogenic transformation are scarcely understood. The relationship between METΔ14EX and SMAD2 has not been studied yet.

METHODS

We generate METΔ14EX models by CRISPR-Cas9. In vitro transwell, wound-healing, soft-agar assay, in vivo metastasis and subcutaneous recurrence assay were used to study the role of METΔ14EX in tumour progression. RNA-seq, Western blotting, co-immunoprecipitation (CO-IP) and immunofluorescent were performed to explore the interaction between c-Met and SMAD2.

RESULTS

Our results demonstrated that METΔ14EX, independent of HGF, can prolong the constitutive activation of c-Met downstream signalling pathways by impeding c-Met degradation and facilitating tumour metastasis and recurrence. Meanwhile, METΔ14EX strengthens the interaction between c-Met and SMAD2, promoting SMAD2 phosphorylation. Therapeutically, MET inhibitor crizotinib impedes METΔ14EX-mediated tumour metastasis by decreasing SMAD2 phosphorylation.

CONCLUSIONS

These data elucidated the previously unrecognised role of METΔ14EX in cancer progression via activation of SMAD2 independent of TGF-β, which helps to develop more effective therapies for such patients. METΔ14EX alteration significantly triggers tumour progression via activation of SMAD2 signalling that are involved in activating tumour invasion, metastasis and recurrence. On the left, in the MET wild-type (METWT), the juxtamembrane (JM) domain is involved in the regulation of tyrosine kinase activity, receptor degradation, and caspase cleavage. On the right, the METΔ14EX mutation leads to the loss of the juxtamembrane domain, resulting in an abnormal MET protein lacking a CBL-binding site. This causes the accumulation of truncated MET receptors followed by constitutive activation of the MET signalling pathway. Thus, the METΔ14EX-mutated protein has strong binding and phosphorylation to SMAD2, which results in the phosphorylation of a large number of SMAD2/3 proteins that combine with SMAD4 to form a complex in the nucleus, activating downstream signalling pathways, such as EMT and ECM remodelling, resulting in tumour progression and recurrence. TF transcription factor.

Ellagic acid promotes osteoblasts differentiation via activating SMAD2/3 pathway and alleviates bone mass loss in OVX mice

Characterized by bone mass loss, osteoporosis is an orthopedic disease typically found in postmenopausal women and aging individuals. Consistent with its pathogenesis summarized as an imbalance in bone formation/resorption, current pharmacologically therapeutic strategies for osteoporosis mainly aim to promote bone formation or/and inhibit bone resorption. However, few effective drugs with mild clinical side effects have been developed, making it a well-concerned issue to seek appropriate drugs for osteoporosis. In this study, we investigated the effect of ellagic acid (EA) on osteogenesis in vitro and in vivo and searched for its molecular mechanism. Here, we showed that EA promoted osteogenic differentiation of MSCs, increased mRNA and protein expression levels of osteoblast marker genes Runt-related transcription factor2, Osterix, Alkaline phosphatase, Collagen type I alpha 1, Osteopontin and Osteocalcin. Furthermore, ovariectomized mice with orally administered EA (10 mg/kg, 50 mg/kg) had significantly higher bone mass than those in controls. And experiments such as fluorescence double-labeling and enzyme-linked immunosorbent assay also demonstrated that EA could promote osteogenesis in vivo. To probe the molecular mechanism of EA, we performed RNA sequencing analysis using EA-treated BMSCs. Significant up-regulation of SMAD2/3 transcription factors was identified by RNA-seq, and it was confirmed in vitro that EA promoted bone formation by activating the SMAD2/3 signaling pathway. Evidence from our present experiments indicates that EA may be a promising candidate for clinical treatment for osteoporosis in future.

Imperatorin ameliorates kidney injury in diabetic mice by regulating the TGF-β/Smad2/3 signaling axis, epithelial-to-mesenchymal transition, and renal inflammation

Diabetic nephropathy (DN) is a serious concern in patients with diabetes mellitus. Prolonged hyperglycemia induces oxidative damage, chronic inflammation, and build-up of extracellular matrix (ECM) components in the renal cells, leading to kidney structural and functional changes. Imperatorin (IMP) is a naturally occurring furanocoumarin derivative with proven antioxidative and anti-inflammatory properties. We investigated whether IMP could improve DN and employed high glucose (HG)-induced HK-2 cells and high-fat diet-fed streptozotocin (HFD/STZ)-generated DN experimental model in C57BL/6 mice. In vitro, IMP effectively reduced the HG-activated reactive oxygen species generation, disturbance in the mitochondrial membrane potential (MMP) and epithelial-to-mesenchymal transition (EMT)-related markers, and the transforming growth factor (TGF)-β and collagen 1 expression in HK-2 cells. In vivo, we found an elevation of serum creatinine, kidney histology alterations, and collagen build-up in the kidneys of the DN control group. Also, we found an altered expression of EMT-related markers, upregulation of the TGF-β/Smad2/3 axis, and elevated pro-inflammatory molecules, TNF-α, IL-1β, IL-18 and phospho-NF-kB (p65) in the DN control group. IMP treatment did not significantly reduce the blood glucose level compared to the DN control group. However, IMP treatment effectively improved renal damage by ameliorating kidney histological changes and serum renal injury markers. IMP treatment restored renal antioxidants and exhibited anti-inflammatory effects in the kidneys. Moreover, the abnormal manifestation of EMT-related attributes and elevated levels of TGF-β, phospho-Smad2/3, and collagen 1 were also normalized in the IMP treatment group. Our findings highlight that IMP may be a potential candidate for treating DN.

BRD9-SMAD2/3 Orchestrates Stemness and Tumorigenesis in Pancreatic Ductal Adenocarcinoma

BACKGROUND & AIMS

The dismal prognosis of pancreatic ductal adenocarcinoma (PDAC) is linked to the presence of pancreatic cancer stem-like cells (CSCs) that respond poorly to current chemotherapy regimens. The epigenetic mechanisms regulating CSCs are currently insufficiently understood, which hampers the development of novel strategies for eliminating CSCs.

METHODS

By small molecule compound screening targeting 142 epigenetic enzymes, we identified that bromodomain-containing protein BRD9, a component of the BAF histone remodeling complex, is a key chromatin regulator to orchestrate the stemness of pancreatic CSCs via cooperating with the TGFβ/Activin-SMAD2/3 signaling pathway.

RESULTS

Inhibition and genetic ablation of BRD9 block the self-renewal, cell cycle entry into G0 phase and invasiveness of CSCs, and improve the sensitivity of CSCs to gemcitabine treatment. In addition, pharmacological inhibition of BRD9 significantly reduced the tumorigenesis in patient-derived xenografts mouse models and eliminated CSCs in tumors from pancreatic cancer patients. Mechanistically, inhibition of BRD9 disrupts enhancer-promoter looping and transcription of stemness genes in CSCs.

CONCLUSIONS

Collectively, the data suggest BRD9 as a novel therapeutic target for PDAC treatment via modulation of CSC stemness.

TGFβ1-driven SMAD2/3 phosphorylation and myofibroblast emergence are fully dependent on the TGFβ1 pre-activation of MAPKs and controlled by maternal leucine zipper kinase

Following wounding, endogenously secreted TGFβs drive resident and bone marrow-derived cells to convert into α-smooth actin (SMA)-rich, contractile myofibroblasts. The TGFβ effect is initiated by the phosphorylation of SMADs 2 and 3 (SMAD2/3). This event has been referred to as the canonical response to TGFβ. TGFβ also elicits other responses viewed as parallel events not directly connected to the SMAD activation, and thus referred to as noncanonical. A recognized response is the phosphorylation of the -activated kinase (TAK1/MAP3K), an upstream component of the mitogen-activated protein kinase (MAPK) cascade. We have now examined the relationship between these two effects of TGFβ1 at their earliest stages. The bulk of the studies were carried out with primary fibroblasts derived from the human cornea. The results' widespread relevance was confirmed in critical experiments with dermal-, and Tenon's capsule-derived fibroblasts. Cells were treated with kinase inhibitors or targeting siRNAs followed by induction by 2 ng/ml TGFβ1, and/or 10 ng/ml TNF-α. Cells were collected after 1 to 30 min for Western blot analysis and assayed for the accumulation of phosphorylated TAK1, ASK1, JNK1/2, p38, HPS27, MELK, SMAD2/3, and GAPDH. The effect of the kinase inhibitors on α-SMA expression and α-SMA stress fiber organization was also tested. For the immediate response to TGFβ1 we found that a) activation of the MAPK pathway was completed within 1 min after the addition of TGFβ1; b) phosphorylation of JNK1/2 was fully dependent on TAK1 and ASK1 activity, c) phosphorylation of MELK was fully dependent on JNK1/2 activity; d) phosphorylation of ASK1 depends on MELK activity, indicating the existence of an ASK1-MELK positive activation feedback loop; e) phosphorylation of SMAD2/3 started only after a 5 min period and reached a nadir after 10-15 min, f) the latter phosphorylation was fully blocked by inhibition of TAK1, ASK1, JNK1/2, and MELK, and siRNA-driven MELK downregulation; g) the inhibitors equally blocked the α-SMA protein expression, stress fiber development, and cell morphology changes at 72 h. These results demonstrate that the activation of the canonical pathway is fully subordinate to the activity of the MAPK pathway, challenging the concept of canonical and noncanonical TGFβ pathways and that SMAD2/3 activation is mediated by MELK, a kinase not previously associated with rapid pharmacological responses.

SET8 is a novel negative regulator of TGF-β signaling in a methylation-independent manner

Transforming growth factor β (TGF-β) is a multifunctional cytokine that induces a diverse set of cellular processes principally through Smad-dependent transcription. Transcriptional responses induced by Smads are tightly regulated by Smad cofactors and histone modifications; however, the underlying mechanisms have not yet been elucidated in detail. We herein report lysine methyltransferase SET8 as a negative regulator of TGF-β signaling. SET8 physically associates with Smad2/3 and negatively affects transcriptional activation by TGF-β in a catalytic activity-independent manner. The depletion of SET8 results in an increase in TGF-β-induced plasminogen activator inhibitor-1 (PAI-1) and p21 expression and enhances the antiproliferative effects of TGF-β. Mechanistically, SET8 occupies the PAI-1 and p21 promoters, and a treatment with TGF-β triggers the replacement of the suppressive binding of SET8 with p300 on these promoters, possibly to promote gene transcription. Collectively, the present results reveal a novel role for SET8 in the negative regulation of TGF-β signaling.

MicroRNA-499-5p inhibits transforming growth factor-β1-induced Smad2 signaling pathway and suppresses fibroblast proliferation and collagen synthesis in rat by targeting TGFβ-R1

BACKGROUND

Artial fibrosis has been recognized as a typical pathological change in atrial fibrillation. Although present evidence suggests that microRNA-499-5p (miR-499-5p) plays an important role in the development of atrial fibrosis, the specific mechanism is not fully understood. Therefore, this study attempted to assess the influence of miR-499-5p on atrial fibroblasts and explore the potential molecular mechanism.

METHODS

Atrial fibroblasts from sprague dawley rat were respectively transfected with miR-499-5p mimic, miR-499-5p negative control and miR-499-5p inhibitor, atrial fibroblasts without any treatment were also established. Cell counting kit-8 assay and transwell assay were used to detect the proliferation and migration of atrial fibroblasts in each group. Expressions of miR-499-5p, TGF-β1, smad2, α-SMA, collagen-I and TGFβ-R1 in mRNA and protein level were subsequently detected via quantitative real-time polymerase chain reaction and western blot. Furthermore, the prediction of the binding sites of miR-499-5p and TGFβ-R1 was performed via the bioinformatics online software TargetScan and verified by dual luciferase reporter.

RESULTS

By utilizing miR-499-5p-transfected atrial fibroblasts model, expression of miR-499-5p in the miR-499-5p mimic group was upregulated, while it was downregulated in the miR-499-5p inhibitors group. Upregulated miR-499-5p expression led to to a significant decrease in the proliferative and migratory ability of cultured atrial fibroblasts, while downregulated miR-499-5p expression led to a significant increase in the proliferative and migratory ability of cultured atrial fibroblasts. Additionally, upregulated miR-499-5p expression made a significant rise in TGF-β1-induced mRNA and protein expression of TGF-β1, TGFβ-R1, smad2, α-SMA and collagen-I in atrial fibroblasts. Furthermore, results from the dual luciferase reporter conformed that miR-499-5p may repress TGFβ-R1 by binding the 3'UTR of TGFβ-R1 directly.

CONCLUSIONS

miR-499-5p is able to inhibit the activation of transforming growth factor β-induced Smad2 signaling and eventually suppressed the proliferation, migration and invasion of atrial fibroblasts and collagen synthesis by targeting TGFβ-R1.

Separating friend from foe: Inhibition of TGF-β-induced detrimental SMAD1/5/9 phosphorylation while maintaining protective SMAD2/3 signaling in OA chondrocytes

OBJECTIVE

Transforming growth factor-β (TGF-β) signaling via SMAD2/3 is crucial to control cartilage homeostasis. However, TGF-β can also have detrimental effects by signaling via SMAD1/5/9 and thereby contribute to diseases like osteoarthritis (OA). In this study, we aimed to block TGF-β-induced SMAD1/5/9 signaling in primary human OA chondrocytes, while maintaining functional SMAD2/3 signaling.

DESIGN

Human OA chondrocytes were pre-incubated with different concentrations of ALK4/5/7 kinase inhibitor SB-505124 before stimulation with TGF-β. Changes in SMAD C-terminal phosphorylation were analyzed using Western blot and response genes were measured with quantitative Polymerase Chain Reaction. To further explore the consequences of our ability to separate pathways, we investigated TGF-β-induced chondrocyte hypertrophy.

RESULTS

Pre-incubation with 0.5 µM SB-505124, maintained ±50% of C-terminal SMAD2/3 phosphorylation and induction of JUNB and SERPINE1, but blocked SMAD1/5/9-C phosphorylation and expression of ID1 and ID3. Furthermore, TGF-β, in levels comparable to those in the synovial fluid of OA patients, resulted in regulation of hypertrophic and dedifferentiation markers in OA chondrocytes; i.e. an increase in COL10, RUNX2, COL1A1, and VEGF and a decrease in ACAN expression. Interestingly, in a subgroup of OA chondrocyte donors, blocking only SMAD1/5/9 caused stronger inhibition on TGF-β-induced RUNX2 than blocking both SMAD pathways.

CONCLUSION

Our findings indicate that using low dose of SB-505124 we maintained functional SMAD2/3 signaling that blocks RUNX2 expression in a subgroup of OA patients. We are the first to show that SMAD2/3 and SMAD1/5/9 pathways can be separately modulated using low and high doses of SB-505124 and thereby split TGF-β's detrimental from protective function in chondrocytes.

Hypoxia enhances anti-fibrotic properties of extracellular vesicles derived from hiPSCs via the miR302b-3p/TGFβ/SMAD2 axis

BACKGROUND

Cardiac fibrosis is one of the top killers among fibrotic diseases and continues to be a global unaddressed health problem. The lack of effective treatment combined with the considerable socioeconomic burden highlights the urgent need for innovative therapeutic options. Here, we evaluated the anti-fibrotic properties of extracellular vesicles (EVs) derived from human induced pluripotent stem cells (hiPSCs) that were cultured under various oxygen concentrations.

METHODS

EVs were isolated from three hiPSC lines cultured under normoxia (21% O2; EV-N) or reduced oxygen concentration (hypoxia): 3% O2 (EV-H3) or 5% O2 (EV-H5). The anti-fibrotic activity of EVs was tested in an in vitro model of cardiac fibrosis, followed by a detailed investigation of the underlying molecular mechanisms. Sequencing of EV miRNAs combined with bioinformatics analysis was conducted and a selected miRNA was validated using a miRNA mimic and inhibitor. Finally, EVs were tested in a mouse model of angiotensin II-induced cardiac fibrosis.

RESULTS

We provide evidence that an oxygen concentration of 5% enhances the anti-fibrotic effects of hiPS-EVs. These EVs were more effective in reducing pro-fibrotic markers in activated human cardiac fibroblasts, when compared to EV-N or EV-H3. We show that EV-H5 act through the canonical TGFβ/SMAD pathway, primarily via miR-302b-3p, which is the most abundant miRNA in EV-H5. Our results show that EV-H5 not only target transcripts of several profibrotic genes, including SMAD2 and TGFBR2, but also reduce the stiffness of activated fibroblasts. In a mouse model of heart fibrosis, EV-H5 outperformed EV-N in suppressing the inflammatory response in the host and by attenuating collagen deposition and reducing pro-fibrotic markers in cardiac tissue.

CONCLUSIONS

In this work, we provide evidence of superior anti-fibrotic properties of EV-H5 over EV-N or EV-H3. Our study uncovers that fine regulation of oxygen concentration in the cellular environment may enhance the anti-fibrotic effects of hiPS-EVs, which has great potential to be applied for heart regeneration.

Activin A/ACVR2A axis inhibits epithelial-to-mesenchymal transition in colon cancer by activating SMAD2

Colorectal cancer is one of the most common malignancies worldwide. Liver metastasis is the major direct cause of colorectal cancer-related deaths. Although radical resection is the most effective treatment for colorectal cancer liver metastasis, several patients are not eligible for surgery. Therefore, there is a need to develop novel treatments based on the understanding of the biological mechanisms underlying liver metastasis in colorectal cancer. This study demonstrated that activin A/ACVR2A inhibits colon cancer cell migration and invasion, as well as suppresses the epithelial-to-mesenchymal transition of mouse colon cancer cells. This finding has been further validated in animal experiments. Mechanistic studies revealed that activin A binds to Smad2 (instead of Smad3) and activates its transcription. Analysis of the paired clinical samples further confirmed that the expression levels of ACVR2A and SMAD2 were the highest in adjacent healthy tissues, followed by primary colon cancer tissues and liver metastasis tissues, suggesting that ACVR2A downregulation may promote colon cancer metastasis. Bioinformatics analysis and clinical studies demonstrated that ACVR2A downregulation was significantly associated with liver metastasis and poor disease-free and progression-free survival of patients with colon cancer. These results suggest that the activin A/ACVR2A axis promotes colon cancer metastasis by selectively activating SMAD2. Thus, targeting ACVR2A is a potential novel therapeutic strategy to prevent colon cancer metastasis.

Impact of SMAD2 and MET Expression on Lymph Node Metastasis of HER2-positive Gastric Cancer Cells

BACKGROUND/AIM

Intra-tumoral heterogeneity, which is frequently found in various types of cancers, has been suggested to play an important role in cancer progression and metastasis. The findings of our previous study suggested that p-SMAD2 and c-MET signaling might play important roles in the progression to lymph node metastasis of HER2-positive gastric cancer. In this study, we confirmed the effect of SMAD2/MET signaling in the progression of HER2-positive gastric cancer in an animal model.

MATERIALS AND METHODS

NCI-N87 cells over-expressing ERBB2, SMAD2, MET were used. To confirm the role of SMAD2 and MET expression on lymph node metastasis of gastric cancer, we orthotopically injected NCI-N87 cells with or without the knockdown of both SMAD2 and MET into the gastric walls of BALBc nude mice.

RESULTS

The number of metastatic lymph nodes was significantly smaller in the knockdown group compared to that in the control group. However, there was no significant difference in gastric tumor size between the two groups.

CONCLUSION

SMAD2 and MET signaling might play important roles specifically in the progression to lymph node metastasis of HER2-positive gastric cancer. c-MET and SMAD2 may be useful targets for preventing lymph node metastasis in patients with HER2-positive gastric cancer.

SIRT2 alleviated renal fibrosis by deacetylating SMAD2 and SMAD3 in renal tubular epithelial cells

Transforming growth factor-β (TGF-β) is the primary factor that drives fibrosis in most, if not all, forms of chronic kidney disease. In kidneys that are obstructed, specific deletion of Sirt2 in renal tubule epithelial cells (TEC) has been shown to aggravate renal fibrosis, while renal tubule specific overexpression of Sirt2 has been shown to ameliorate renal fibrosis. Similarly, specific deletion of Sirt2 in hepatocyte aggravated CCl4-induced hepatic fibrosis. In addition, we have demonstrated that SIRT2 overexpression and knockdown restrain and enhance TGF-β-induced fibrotic gene expression, respectively, in TEC. Mechanistically, SIRT2 reduced the phosphorylation, acetylation, and nuclear localization levels of SMAD2 and SMAD3, leading to inhibition of the TGF-β signaling pathway. Further studies have revealed that that SIRT2 was able to directly interact with and deacetylate SMAD2 at lysine 451, promoting its ubiquitination and degradation. Notably, loss of SMAD specific E3 ubiquitin protein ligase 2 abolishes the ubiquitination and degradation of SMAD2 induced by SIRT2 in SMAD2. Regarding SMAD3, we have found that SIRT2 interact with and deacetylates SMAD3 at lysine 341 and 378 only in the presence of TGF-β, thereby reducing its activation. This study provides initial indication of the anti-fibrotic role of SIRT2 in renal tubules and hepatocytes, suggesting its therapeutic potential for fibrosis.

SMAD2 inhibits pyroptosis of fibroblast-like synoviocytes and secretion of inflammatory factors via the TGF-β pathway in rheumatoid arthritis

OBJECTIVE

Rheumatoid arthritis (RA) is a chronic, progressive autoimmune disease. Over-activation of fibroblast-like synoviocytes is responsible for the hyperplasia of synovium and destruction of cartilage and bone and pyroptosis of FLS plays a key role in those pathological processes during RA. This study investigated the detailed mechanisms that SMAD2 regulates the pyroptosis of FLS and secretion of inflammatory factors in rheumatoid arthritis.

METHODS

We collected synovial tissues of RA patients and FLS-RA and cultured FLS for detection of expression of SMAD2. ASC, NLRP3, cleaved-caspase-1, and GSDMD-N were detected by Western blot after overexpression of SMAD2. Besides, flow cytometry, electron microscope, ELISA, HE staining, and Safranin O staining were performed to further demonstrate that SMAD2 can affect the pyroptosis of FLS-RA.

RESULTS

The expression of SMAD2 was down-regulated in synovial tissues of RA patients and FLS-RA. Overexpression of SMAD2 can inhibit the expression of ASC, NLRP3, cleaved-caspase-1, and GSDMD-N. Flow cytometry and electron microscope further demonstrated that SMAD2 attenuated pyroptosis of FLS-RA. In addition, overexpression of SMAD2 also inhibited inflammatory factors such as IL-1β, IL-18, IL-6, and IL-8 secretion and release of LDH. Besides, overexpression of SMAD2 can reverse the decrease of p-SMAD2 and TGF-TGF-β induced by nigericin. In vivo experiments on CIA rats further demonstrated that overexpression of SMAD2 by local intra-articular injection of LV-SMAD2 can effectively alleviate joint redness, swelling, and destruction of cartilage and bones.

CONCLUSION

SMAD2 inhibited FLS-RA pyroptosis by down-regulating of NLRP3 inflammasomes (NLRP3, ASC, and caspase-1 complex) and eased the secretion of inflammatory factors via the TGF-β signaling pathway, thereby improving the symptom of RA. We hope that this study may provide a new research idea for RA and a potential target for the treatment of RA.

Mustard Gas Exposure Actuates SMAD2/3 Signaling to Promote Myofibroblast Generation in the Cornea

Sulfur mustard gas (SM) is a vesicating and alkylating agent used as a chemical weapon in many mass-casualty incidents since World War I. Ocular injuries were reported in >90% of exposed victims. The mechanisms underlying SM-induced blindness remain elusive. This study tested the hypothesis that SM-induced corneal fibrosis occurs due to the generation of myofibroblasts from resident fibroblasts via the SMAD2/3 signaling pathway in rabbit eyes in vivo and primary human corneal fibroblasts (hCSFs) isolated from donor corneas in vitro. Fifty-four New Zealand White Rabbits were divided into three groups (Naïve, Vehicle, SM-Vapor treated). The SM-Vapor group was exposed to SM at 200 mg-min/m3 for 8 min at the MRI Global facility. Rabbit corneas were collected on day 3, day 7, and day 14 for immunohistochemistry, RNA, and protein lysates. SM caused a significant increase in SMAD2/3, pSMAD, and ɑSMA expression on day 3, day 7, and day 14 in rabbit corneas. For mechanistic studies, hCSFs were treated with nitrogen mustard (NM) or NM + SIS3 (SMAD3-specific inhibitor) and collected at 30 m, 8 h, 24 h, 48 h, and 72 h. NM significantly increased TGFβ, pSMAD3, and SMAD2/3 levels. On the contrary, inhibition of SMAD2/3 signaling by SIS3 treatment significantly reduced SMAD2/3, pSMAD3, and ɑSMA expression in hCSFs. We conclude that SMAD2/3 signaling appears to play a vital role in myofibroblast formation in the cornea following mustard gas exposure.

LINC01232 promotes lung squamous cell carcinoma progression through modulating miR-181a-5p/SMAD2 axis

BACKGROUND

LINC01232 has been implicated in the progression of multiple malignancies. Yet, the function of LINC01232 in the carcinogenesis of lung squamous cell carcinoma (LUSC) remains unclear. This study aims to examine the role LINC01232 plays in LUSC progression.

METHODS

mRNA and protein levels were assessed using qRT-PCR and western blot, respectively. Cell proliferation was assessed by CCK-8 and colony formation assays. Cell migration and invasion were evaluated by transwell assay. The interactions between LINC01232, miR-181a-5p, and SMAD2 were assessed using luciferase reporter, RNA pull-down, and RNA immunoprecipitation (RIP) assays. The subcellular distribution of LINC01232 was examined by cytosolic/nuclear fractionation assay RESULTS: LINC01232 was upregulated in both LUSC tissues and cell lines. Knockdown of LINC01232 impaired cell proliferation, migration and invasion capability in H1229 and A549 cells, a phenotype that could be reversed by miR-181a-5p silencing. In addition, LINC01232 silencing reduced levels of N-cadherin, Vimentin, and Snail in H1229 and A549 cells, but increased the level of E-cadherin, which can be abrogated by miR-181a-5p inhibitors.

CONCLUSIONS

In summary, our study demonstrates that LINC01232 expression increases in LUSC tissues and cell lines and promotes LUSC progression by modulating the miR-181a-5p/SMAD2 signaling, providing new potential drug targets for LUSC treatment.

M6A RNA methylation-mediated RMRP stability renders proliferation and progression of non-small cell lung cancer through regulating TGFBR1/SMAD2/SMAD3 pathway

Non-small cell lung cancer (NSCLC) has the highest mortality rate among all malignancies worldwide. The role of long noncoding RNAs (lncRNAs) in the progression of cancers is a contemporary research hotspot. Based on an integrative analysis of The Cancer Genome Atlas database, we identified lncRNA-RNA Component of Mitochondrial RNA Processing Endoribonuclease (RMRP) as one of the most highly upregulated lncRNAs that are associated with poor survival in NSCLC. Furthermore, N(6)-methyladenosine (m6A) was highly enriched within RMRP and enhanced its RNA stability. In vitro and in vivo experiments showed that RMRP promoted NSCLC cell proliferation, invasion, and migration. In terms of mechanism, RMRP recruited YBX1 to the TGFBR1 promotor region, leading to upregulation of the transcription of TGFBR1. The TGFBR1/SMAD2/SMAD3 pathway was also regulated by RMRP. In addition, RMRP promoted the cancer stem cells properties and epithelial mesenchymal transition, which promote the resistance to radiation therapy and cisplatin. Clinical data further confirmed a positive correlation between RMRP and TGFBR1. In short, our work reveals that m6A RNA methylation-mediated RMRP stability renders proliferation and progression of NSCLC through regulating TGFBR1/SMAD2/SMAD3 pathway.

RBM15 silencing promotes ferroptosis by regulating the TGF-β/Smad2 pathway in lung cancer

OBJECTIVE

We assessed the function and mechanism of RNA binding motif protein 15 (RBM15) silencing in lung cancer development.

METHODS

The effects of RBM15 knockdown on A549 and H1299 cells were evaluated by MTT, EdU, wound healing, and transwell assay. We then detected the functions of RBM15 silencing on lipid peroxidation, labile iron pool (LIP), ferrous iron (Fe²⁺ ), and ferroptosis-related genes. RNA sequencing was performed after RBM15 knockout in lung cancer cells, followed by differentially expressed genes (DEGs), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were performed. Finally, the expression of RBM15 and pathway-related genes was determined by western blot.

RESULTS

RBM15 was highly expressed in lung cancer cells. RBM15 silencing reduced the viability, inhibited cell proliferation, invasion, and migration, and suppressed tumor growth in the xenograft mouse model. Knockout of RBM15 regulated ferroptosis-related gene expression. LIP, Fe²⁺ , and lipid peroxidation were distinctly increased by the knockout of RBM15. RNA-seq sequencing revealed that there are 367 up-regulated and 368 down-regulated DEGs, which were enriched in molecular functions, biological processes, and cellular components. RBM15 silencing reduced the expression of TGF-β/Smad2, and TGF-β activator (SRI-011381) reversed the inhibitory effect of RBM15 silencing on tumor cell growth.

CONCLUSION

We demonstrated that RBM15 silencing promoted ferroptosis in lung cancer cells by TGF-β/Smad2 pathway, thereby inhibiting lung cancer cell growth, which may provide new light for lung cancer treatment.

Endoplasmic reticulum stress mediates nickel chloride-induced epithelial‑mesenchymal transition and migration of human lung cancer A549 cells through Smad2/3 and p38 MAPK activation

BACKGROUND

The endoplasmic reticulum (ER) is a cellular membrane-bound organelle whereby proteins are synthesized, folded and glycosylated. Due to intrinsic (e.g., genetic) and extrinsic (e.g., environmental stressors) perturbations, ER proteostasis can be deregulated within cells which triggers unfolded protein response (UPR) as an adaptive stress response that may impact the migration and invasion properties of cancer cells. However, the mechanisms underlying the nickel compounds on lung cancer cell migration and invasion remain uncertain.

OBJECTIVE

We aimed to study whether Nickel chloride (NiCl₂) induces ER stress in lung cancer cells, and whether ER stress is involved in modulating epithelial-mesenchymal transition (EMT) and migration by Smads and MAPKs pathways activation following NiCl₂ treatment.

METHODS

A549 cells were treated with NiCl₂ to determine the cell viability using MTT assay. The wound healing assay was used to evaluate cell migration ability. ER ultrastructure was observed by transmission electron microscopy. Western blotting assay was performed to evaluate the protein levels of BIP, PERK, IRE-1α, XBP-1 s, and ATF6 for ER stress and UPR, E-cadherin and Vimentin for EMT, p-Smad2/3, p-ERK, p-JNK, and p-P38 for activation of Smads and MAPKs signaling pathways.

RESULTS

The expression levels of BIP, PERK, IRE-1α, XBP-1 s, and ATF6 were significantly increased following treatment with NiCl₂ in time- and dose-effect relationship. The ER stress inhibitor 4-PBA downregulated the expression levels of the above five proteins, and reversed the decrease in E-cadherin protein level and the increase in vimentin protein expression and cell migration abilities caused by NiCl₂. Furthermore, 4-PBA significantly reduced nickel chloride-induced Smad2/3 and p38 MAPK pathway activation, while not affected ERK and JNK MAPK pathways.

CONCLUSION

NiCl₂ triggers ER stress and UPR in A549 cells. Moreover, 4-PBA alleviates NiCl₂-induced EMT and migration ability of A549 cells possibly through the Smad2/3 and p38 MAPK pathways activation, rather than ERK and JNK MAPK pathways.

Indole-derived compound SIS3 targets a subset of activated Smad complexes

Smad2 and Smad3 are receptor-regulated Smad proteins that transmit signals from cytokines belonging to the transforming growth factor (TGF)-β family, which are vital for adult tissue homeostasis. The overactivation of such proteins often engenders the development of pathological conditions. Smad3 reportedly mediates TGF-β–induced fibrosis. Although various potential Smad3-specific inhibitors are being developed, their specificity and action mechanisms remain largely unknown. This study aimed to establish a biochemical platform to monitor Smad2- or Smad3-dependent TGF-β signaling using SMAD2, SMAD3 and SMAD2/3 knockout cell lines alongside TGF-β–dependent luciferase reporters and Smad mutant proteins. Using this platform, SIS3, an indole-derived compound widely used as a specific Smad3 inhibitor, was observed to preferentially suppress a subset of activated Smad complexes. However, its inhibition did not favor Smad3 signaling over Smad2 signaling. These findings indicate that SIS3 can be employed as a probe to examine the heterogeneous nature of Smad signaling that induces gene expression. However, its use as a Smad3-specific inhibitor should be avoided.

[Pilose antler polypeptide CNT14 promoted proliferation and migration of human oral mucosa fibroblast cells]

PURPOSE

To explore the effect of pilose antler polypeptides CNT14 on proliferation and migration of human oral mucosa fibroblast (hOMF) cells and the related molecular mechanism.

METHODS

The biosafety of pilose antler polypeptides CNT14 on hOMF cells was verified by live-dead cell staining kit.CCK-8 assay was used to detect the effect of pilose antler polypeptides CNT14 on hOMF cell proliferation. The effect of pilose antler polypeptides CNT14 on hOMF cell migration was detected by scratch test. Western blot was used to detect the expression of α-SMA, TGF-β1, Smad2 and p-Smad2 proteins in hOMF cells stimulated by pilose antler polypeptides CNT14. The effect of Smad2 inhibitors on fibroblast activation induced by pilose antler polypeptides CNT14 was evaluated.The model of keratinized gingival defect was established in New Zealand white rabbits, and the regenerated gingival tissue was stained with H-E. The expression levels of α-SMA, TGF-β1, Smad2 and p-Smad2 proteins in the gingival tissues of regenerated New Zealand white rabbits were detected by immunohistochemistry, and the ability of pilose antler polypeptides CNT14 to promote regeneration of oral gingival tissues was verified. Statistical analysis was performed with SPSS 20.0 software package.

RESULTS

The survival rate of hOMF cells was above 95% after treated with pilose antler polypeptides CNT14. After stimulation of hOMF cells with pilose antler polypeptides CNT14, the proliferation and migration rates of hOMF cells were increased compared with the control group (P＜0.05). The expression of α-SMA, TGF-β1, Smad2 and p-Smad2 proteins in hOMF cells stimulated by pilose antler peptide CNT14 was increased, and the difference was statistically significant(P＜0.05). The expression of α-SMA in fibroblasts induced by Smad2 inhibitor was decreased. In animal experiments, H-E staining showed that the inflammatory response of oral mucosal wounds of New Zealand white rabbits treated with CNT14 was less than that of the control group. Immunohistochemical staining results showed that the expressions of α-SMA, TGF-β1, Smad2 and p-Smad2 in the regenerated gingival tissues of New Zealand white rabbits treated with CNT14 were significantly increased compared with those in the control group on the 9th and 11th days within the gingival wounds(P＜0.05).

CONCLUSIONS

Pilose antler polypeptides CNT14 has good biosafety and can promote the proliferation and migration of human oral mucosa fibroblast cells, and the expression levels of α-SMA, TGF-β1, Smad2 and p-Smad2 were increased, promoting the regeneration of gingival tissues.

Circ TYMP1 Inhibits Carcinogenesis and Cisplatin Resistance in Ovarian Cancer by Reducing Smad2/3 Phosphorylation via a MicroRNA-182A-3p/TGF1B Axis

TYMP1 is a cancer driver in several human malignancies. However, its significance in ovarian cancer (ovarian carcinoma) remains uncertain. This research aims to understand the TYMP1's role in ovarian carcinoma carcinogenesis and cisplatin (DDP) resistance and its molecular ovarian marchionesses. Circ TYMP1 overexpression in ovarian carcinoma samples led to an accelerated tumor stage. Bioinformatics identified miR-182A-3p as the TYMP1's target transcript. Circ TYMP1 functioned as a sponge for miR-182A-3p, lowering its inhibitory effect on TGF1B. Downregulating circ TYMP1 decreased A2780-Res cell proliferation, invasion, and death resistance. Malignant ovarian carcinoma cells recovered following miR-182A-3p downregulation. TGF1B overexpression boosted A2780-Res cell proliferation, aggression, and cisplatin resistance while reducing Smad2/3 phosphorylation. TYMP1 sequesters miR-182A-3p and promotes TGF1B in ovarian carcinoma, boosting carcinogenesis and cisplatin resistance. This might lead to novel ovarian carcinoma treatments.

Ethanol extract of Pharbitis nil ameliorates liver fibrosis through regulation of the TGFβ1-SMAD2/3 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Pharbitis nil (L.) Choisy is a medicinal herb, and herbal remedies based on its seeds have been used to treat of obesity and liver diseases, including fatty liver and liver cirrhosis in East Asia.

AIM OF THE STUDY

Liver fibrosis is a major cause of morbidity and mortality in patients with chronic liver inflammation such as that caused by non-alcoholic steatohepatitis. However, no effective pharmaceutical treatment for liver fibrosis has been approved. In this study, we aimed to investigate that ethanol extract of pharbitis nil (PNE) alleviates the liver fibrosis.

MATERIALS AND METHODS

We studied the effects of PNE on two preclinical models. Six-week-old male C57BL/6 mice were intraperitoneally injected with CCl₄ twice weekly for 6 weeks and then treated with 5 or 10 mg/kg PNE daily from week 3 for weeks. Secondly, mice were fed HFD for 41 weeks and at 35 weeks treated with 5 mg/kg PNE daily for the remaining 6 weeks. In addition, we examined the antifibrotic effects of PNE in primary mouse hepatic stellate cells and LX-2 cells.

RESULTS

PNE treatment ameliorated hepatocyte necrosis, inflammation, and liver fibrosis in CCl₄-treated mice and inhibited the progression of liver fibrosis in mice with HFD-induced fibrosis. PNE reduced the expressions of fibrosis markers and SMAD2/3 activations in mouse livers and in TGFβ1-treated primary mouse hepatic stellate and LX-2 cells CONCLUSIONS: This study demonstrates that PNE attenuates liver fibrosis by downregulating TGFβ1-induced SMAD2/3 activation.

[Emodin inhibits the proliferation and migration of human pulmonary artery smooth muscle cells by blocking SMAD2/3 signaling pathway]

Objective To investigate the effect of emodin on the proliferation and migration of human pulmonary artery smooth muscle cells (HPASMCs) induced by transforming growth factor β1 (TGF-β1). Methods HPASMCs were cultured in vitro, and HPASMCs in logarithmic growth phase were divided into control group, TGF-β1 group, and TGF-β1 combined with emodin group. The activity of HPASMCs was detected by CCK-8 assay, the migration ability of HPASMCs was detected by Transwell^TM chamber assay and scratch assay, and the expressions of osteopontin (OPN) and proliferating cell nuclear antigen (PCNA) were detected by immunofluorescence assay. The protein levels of OPN and PCNA and the phosphorylation of SMAD family member 2 (SMAD2) and SMAD family member 2 (SMAD3) in HPASMCs were detected by Western blot. Results Compared with those in the control group, in TGF-β1 group, the protein expressions of OPN and PCNA, the proliferation and migration of HPASMCs, and the phosphorylation of SMAD2 and SMAD3 were increased. Compared with those in the TGF-β1 group, in the TGF-β1 combined with emodin group, the proliferation and migration of HPASMCs, the expressions of OPN and PCNA, and the phosphorylation of SMAD2 and SMAD3 were decreased. Conclusion Emodin inhibits the up-regulation of OPN and PCNA and the proliferation and migration of PASMCs induced by TGF-β1, which may be related to the blocking of SMAD2/3 signaling pathway.

Ochratoxin a induces hepatic fibrosis through TGF-β receptor I/Smad2/3 signaling pathway

Ochratoxin A (OTA) is a mycotoxin generated by Penicillium and Aspergillus species. It is often found in cereals. We hypothesized that OTA exposure induces epithelial-mesenchymal transition (EMT), leading to liver fibrosis. In this research, we explored whether the TGF-β receptor I (TGF-β RI)/Smad2/3 signaling pathway is related to EMT-induced hepatic fibrosis. In vitro and in vivo experiments, mRNA and protein expression of liver fibrosis-related markers such as fibronectin, α-smooth muscle actin (α-SMA) and E-cadherin were assessed. The levels of alkaline phosphatase, alanine transaminase, aspartate aminotransferase, and total bilirubin, which are used to assess damage, increased. We also confirmed the increase in mRNA and protein expression of TGF-β RI, Smad2, and Smad3. The expression of liver fibrosis-related markers was decreased by siRNA-mediated silencing of Smad2/3, as well as TGF-RI suppression. Liver cells exposed to OTA showed enhanced TGF-β RI expression on the cell membrane. These results demonstrated that OTA induces hepatic fibrosis through TGF-β RI and Smad2/3 pathways in vitro and in vivo.

MED1 Downregulation Contributes to TGFβ-Induced Metastasis by Inhibiting SMAD2 Ubiquitination Degradation in Cutaneous Melanoma

Metastasis is the main reason for the high mortality of patients and indeed a difficult task in the treatment of cutaneous melanoma. Therefore, it is of great clinical value to explore the molecular mechanism of cutaneous metastatic melanoma and develop novel therapies. MED1, acting as a factor required for activator-dependent transcription, is reported to be involved in carcinogenesis and progression. In this study, we found that MED1 was highly expressed in patients with cutaneous melanoma. MED1 downregulation could induce cellular epithelial-to-mesenchymal transition and promote migration, invasion, and metastasis of cutaneous melanoma in vivo and in vitro. Further analysis showed that in Med1 knockdown cells, the TGFβ/SMAD2 signaling pathway mediated an increase in epithelial-to-mesenchymal transition phenotype and migration. The opposite results were observed after treatment with TGFβ inhibitors. To further explore the mechanism, we found that MED1 interacted with SMAD2, and MED1 downregulation could protect SMAD2 from degradation by inhibiting SMAD2 ubiquitination. Together, these results suggest that MED1 inhibited TGFβ signaling pathway to reduce cell epithelial-to-mesenchymal transition phenotype and migration through SMAD2 ubiquitination in the metastasis of cutaneous melanoma. Our findings elucidated the role of MED1 in the metastasis of cutaneous melanoma and provided a target for the therapeutic strategies of cutaneous melanoma.

Ambient particulate matter exposure plus a high-fat diet exacerbate renal injury by activating the NLRP3 inflammasome and TGF-β1/Smad2 signaling pathway in mice

BACKGROUND

Chronic kidney disease (CKD) is a public health problem of which the prevalence is increasing worldwide. Several studies have reported that ambient particulate matter (PM) causes kidney injury, which may be related to the risk of CKD. However, the underlying molecular mechanisms have not been fully clarified. In addition, whether a high-fat diet (HFD) could exacerbate ambient PM-induced nephrotoxicity has not been evaluated. This study aimed to investigate the combined effect of ambient PM and a HFD on renal injury.

METHODS AND RESULTS

Male C57BL/6 J mice were fed either a normal diet or a HFD and exposed to filtered air (FA) or particulate matter (PM) for 18 weeks. In the present study, we observed that renal function changed (serum blood urea nitrogen and serum creatinine), and exposure to PM and a HFD caused a synergistic effect on renal injury. Histopathological analysis showed that PM exposure induced renal fibrosis in mice, and combined exposure to PM and a HFD exacerbated these adverse effects. Moreover, ambient PM exposure activated the nucleotide-binding domain and leucine-rich repeat protein 3 (NLRP3) inflammasome and increased the inflammatory response, as indicated by the increases in interleukin-1β, interleukin-6 and tumor necrosis factor-α in the serum and kidney, as well as the upregulation of specific renal fibrosis-related markers (transforming growth factor-β1 and p-Smad2) in the kidney tissues of mice. Furthermore, combined exposure to PM and a HFD augmented these changes in the kidney. In vitro, inhibition of the NLRP3 inflammasome by MCC950 (an inhibitor of NLRP3) reduced the levels of proinflammatory cytokines and the expression of transforming growth factor-β1 and p-Smad2 in HK-2 cells.

CONCLUSION

Taken together, our data indicated that PM exposure caused renal inflammation and induced profibrotic effects on the kidney, and combined exposure to ambient PM and a HFD exacerbated renal injury, which may involve activation of the NLRP3 inflammasome and the TGF-β1/Smad2 signaling pathway.

Capsaicin ameliorates renal fibrosis by inhibiting TGF-β1-Smad2/3 signaling

BACKGROUND AND PURPOSE

Chronic kidney disease (CKD), characterized by renal fibrosis, is a global refractory disease with few effective therapeutic strategies. It has been reported that capsaicin exerts many pharmacological effects including liver and cardiac fibrosis. However, whether capsaicin plays a therapeutic role in renal fibrosis remains unclear.

METHODS

We investigated antifibrotic effects of capsaicin in two mouse renal fibrosis models as follows: C57BL/6J mice were subjected to unilateral ureteral obstruction (UUO) and fed with an adenine-rich diet. We uncovered and verified the mechanisms of capsaicin in human proximal tubular epithelial cells (HK2). We mainly used histochemistry, immunohistochemistry and immunofluorescence staining, western blot assay, biochemical examination and other tools to examine the effects of capsaicin on renal fibrosis and the underlying mechanisms.

RESULTS

Capsaicin treatment significantly alleviated fibronectin and collagen depositions in the tubulointerstitium of the injured kidneys from UUO and adenine-fed mice. Meanwhile, capsaicin treatment obviously reduced α-SMA expression. Moreover, capsaicin treatment dramatically protected against the phenotypic alteration of tubular epithelial cells by increasing E-cadherin expression and decreasing vimentin expression during renal fibrosis. Mechanistically, capsaicin treatment effectively suppressed α-SMA and vimentin expressions but promoted E-cadherin expression in HK2 cells mainly through the inhibition of TGF-β1-Smad2/3 signaling.

CONCLUSION

Capsaicin significantly ameliorated renal fibrosis possibly by retarding the activation of myofibroblasts and protecting against the phenotypic alteration of tubular epithelial cells mainly through the inhibition of TGF-β1-Smad2/3 signaling. Thus, our findings may provide a new insight into the clinical application of capsaicin in renal fibrosis.

Up-regulation of Nrf2/HO-1 and inhibition of TGF-β1/Smad2/3 signaling axis by daphnetin alleviates transverse aortic constriction-induced cardiac remodeling in mice

Oxidative damage and accumulation of extracellular matrix (ECM) components play a crucial role in the adverse outcome of cardiac hypertrophy. Evidence suggests that nuclear factor erythroid-derived factor 2 related factor 2 (Nrf2) can modulate oxidative damage and adverse myocardial remodeling. Daphnetin (Daph) is a coumarin obtained from the plant genus Daphne species that exerts anti-oxidative and anti-inflammatory properties. Herein, we investigated the roles of Daph in transverse aortic constriction (TAC)-induced cardiac hypertrophy and fibrosis in mice. TAC-induced alterations in cardiac hypertrophy markers, histopathological changes, and cardiac function were markedly ameliorated by oral administration of Daph in mice. We found that Daph significantly reduced the reactive oxygen species (ROS) generation, increased the nuclear translocation of Nrf2, and consequently, reinstated the protein levels of NAD(P)H quinone dehydrogenase1 (NQO1), heme oxygenase-1 (HO-1), and other antioxidants in the heart. Besides, Daph significantly inhibited the TAC-induced accumulation of ECM components, including α-smooth muscle actin (α-SMA), collagen I, collagen III, and fibronectin, and interfered with the TGF-β1/Smad2/3 signaling axis. Further studies revealed that TAC-induced terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) positive nuclei and the protein levels of Bax/Bcl2 ratio and cleaved caspase 3 were substantially decreased by Daph treatment. We further characterized the effect of Daph on angiotensin II (Ang-II)-stimulated H9c2 cardiomyoblast cells and observed that Daph markedly decreased the Ang-II induced increase in cell size, production of ROS, and proteins associated with apoptosis and fibrosis. Mechanistically, Daph alone treatment enhanced the protein levels of Nrf2, NQO1, and HO-1 in H9c2 cells. The inhibition of this axis by Si-Nrf2 transfection abolished the protective effect of Daph in H9c2 cells. Taken together, Daph effectively counteracted the TAC-induced cardiac hypertrophy and fibrosis by improving the Nrf2/HO-1 axis and inhibiting the TGF-β1/Smad2/3 signaling axis.

Ginsenoside Rh4 Suppresses Metastasis of Gastric Cancer via SIX1-Dependent TGF-β/Smad2/3 Signaling Pathway

Gastric cancer (GC) is the leading causes of cancer-related death worldwide. Surgery remains the cornerstone of gastric cancer treatment, and new strategies with adjuvant chemotherapy are currently gaining more and more acceptance. Ginsenoside Rh4 has excellent antitumor activity. Conversely, the mechanisms involved in treatment of GC are not completely understood. In this study, we certified that Rh4 showed strong anti-GC efficiency in vitro and in vivo. MTT and colony formation assays were performed to exhibit that Rh4 significantly inhibited cellular proliferation and colony formation. Results from the wound healing assay, transwell assays, and Western blotting indicated that Rh4 restrained GC cell migration and invasion by reversing epithelial–mesenchymal transition (EMT). Further validation by proteomic screening, co-treatment with disitertide, and SIX1 signal silencing revealed that SIX1, a target of Rh4, induced EMT by activating the TGF-β/Smad2/3 signaling pathway. In summary, our discoveries demonstrated the essential basis of the anti-GC metastatic effects of Rh4 via suppressing the SIX1–TGF-β/Smad2/3 signaling axis, which delivers a new idea for the clinical treatment of GC.

The antifibrotic effect of pheretima protein is mediated by the TGF-β1/Smad2/3 pathway and attenuates inflammation in bleomycin-induced idiopathic pulmonary fibrosis

ETHNOPHARMACOLOGICAL RELEVANCE

Pheretima is a traditional Chinese medicine that could treat various lung diseases such as asthma, pneumonia, and lung cancer effectively; however, limited studies on the use of Pheretima protein in the treatment of lung diseases have been conducted to date.

AIM OF THE STUDY

The aim of this study was to explain the antipulmonary fibrosis mechanism of the Pheretima protein and elucidate its possible cell signaling pathways.

MATERIAL AND METHODS

Fresh pheretima was freeze-dried to obtain the Pheretima protein. Divide C57BL/6 mice into control and bleomycin (BLM)-induced models, pirfenidone, and Pheretima protein-treatment groups. Three weeks later, they were treated with H&E and Masson's trichrome staining to assess lung injury and fibrosis. Pulmonary fibrosis was assessed using immunohistochemistry (IHC), realtime-PCR (RT-PCR), and western blotting. Inflammation was assessed using the alveolar lavage fluid.

RESULTS

Pheretima protein inhibited epithelial-mesenchymal transition (EMT) and extracellular matrix (ECM) deposition and reduced inflammation. It also reduced the levels of Smad2/3, pSmad2/3, and transforming growth factor-beta 1 (TGF-β1). Thus, our results indicate that Pheretima protein can alleviate BLM-induced pulmonary fibrosis in a mouse model.

CONCLUSION

Pheretima protein inhibits ECM, EMT, and antiinflammatory markers, which in turn ameliorates BLM-induced pulmonary fibrosis. Preliminary mechanistic studies indicated that Pheretima protein can exert its biological activity by downregulating the TGF-β1/Smad2/3 pathway.

Daidzein suppresses TGF-β1-induced cardiac fibroblast activation via the TGF-β1/SMAD2/3 signaling pathway

Myocardial fibrosis is a concomitant bioprocess associated with many cardiovascular diseases (CVDs). Daidzein is an isoflavone that has been used for the treatment of CVDs. This study aimed to reveal its role in myocardial fibrosis. Our results indicate that daidzein had a nontoxic effect on cardiac fibroblasts and that TGF-β1 and TGFβRI levels were gradually decreased by daidzein in a dose-dependent manner. In the current study, we show that daidzein significantly inhibited TGF-β1-induced mRNA and protein expression of α-SMA, collagen I, and collagen III. Accordingly, immunofluorescence staining of α-SMA was performed. Daidzein also inhibited TGF-β1-induced cardiac fibroblast proliferation and migration. Mechanistically, daidzein inhibited the TGF-β/SMAD signaling pathway induced by TGF-β1 in cardiac fibroblasts. Additionally, daidzein ameliorated MI-induced cardiac dysfunction and cardiac fibrosis in vivo. Based on these findings, we conclude that daidzein reduces TGF-β1-induced cardiac fibroblast activation by partially regulating the TGF-β1/SMAD2/3 signaling pathway.

Mechanisms involved in suppression of osteoclast supportive activity by transforming growth factor-β1 via the ubiquitin-proteasome system

Orthodontic treatment requires the regulation of bone remodeling in both compression and tension sides. Transforming growth factor-β1 (TGF-β1) is an important coupling factor for bone remodeling. However, the mechanism underlying the TGF-β1-mediated regulation of the osteoclast-supporting activity of osteoblasts and stromal cells remain unclear. The current study investigated the effect of TGF-β1 on receptor activator of nuclear factor kappa-B ligand (RANKL) expression in stromal cells induced by 1α,25(OH)2D3 (D3) and dexamethasone (Dex). TGF-β1 downregulated the expression of RANKL induced by D3 and Dex in mouse bone marrow stromal lineage, ST2 cells. Co-culture system revealed that TGF-β1 suppressed osteoclast differentiation from bone marrow cell induced by D3 and Dex-activated ST2 cells. The inhibitory effect of TGF-β1 on RANKL expression was recovered by inhibiting the interaction between TGF-β1 and the TGF-β type I/activin receptor or by downregulating of smad2/3 expression. Interestingly, TGF-β1 degraded the retinoid X receptor (RXR)-α protein which forms a complex with vitamin D receptor (VDR) and regulates transcriptional activity of RANKL without affecting nuclear translocation of VDR and phosphorylation of signal transducer and activator of transcription3 (STAT3). The degradation of RXR-α protein by TGF-β1 was recovered by a ubiquitin-proteasome inhibitor. We also observed that poly-ubiquitination of RXR-α protein was induced by TGF-β1 treatment. These results indicated that TGF-β1 downregulates RANKL expression and the osteoclast-supporting activity of osteoblasts/stromal cells induced by D3 and Dex through the degradation of the RXR-α protein mediated by ubiquitin-proteasome system.

miR-30a-5p inhibits the proliferation and collagen formation of cardiac fibroblasts in diabetic cardiomyopathy

Cardiac fibrosis is one of the major pathological characteristics of diabetic cardiomyopathy (DCM). MicroRNAs (miRNAs, miRs) have been identified as key regulators in the progression of cardiac fibrosis. This study aimed to investigate the role of miR-30a-5p in DCM and the underlying mechanism. The rat model of diabetes mellitus (DM) was established by streptozotocin injection, and the rat primary cardiac fibroblasts (CFs) were isolated from cardiac tissue and then treated with high glucose (HG). MTT assay was performed to assess the viability of CFs. Dual-luciferase reporter gene assay was conducted to verify the interaction between miR-30a-5p and Smad2. The expression of miR-30a-5p was downregulated in the myocardial tissues of DM rats and HG-stimulated CFs. Overexpression of miR-30a-5p reduced Smad2 levels and inhibited collagen formation in HG-stimulated CFs and DM rats, as well as decreased the proliferation of CFs induced by HG. Smad2 was a target of miR-30a-5p and its expression was inhibited by miR-30a-5p. Furthermore, the simultaneous overexpression of Smad2 and miR-30a-5p reversed the effect of miR-30a-5p overexpression alone in CFs. Our results indicated that miR-30a-5p reduced Smad2 expression and also induced a decrease in proliferation and collagen formation in DCM.

Prolyl 4-hydroxylase subunit alpha 3 facilitates human colon cancer growth and metastasis through the TGF-β/Smad signaling pathway

Prolyl 4-hydroxylase subunit alpha 3 (P4HA3) has been known to be associated with a variety of human cancers. However, the role of P4HA3 on colon cancer growth and metastasis is unclear. In this study, we investigated the effect of P4HA3 on the growth and metastasis of colon cancer and its possible molecular mechanism. First of all, we demonstrated that P4HA3 expression was greatly higher in cells and tissues of colon cancer than that in non-tumor tissues and cells, and the prognosis of patients who had higher P4HA3 was distinctively poorer than patients who had lower level of P4HA3. Second, it was shown that P4HA3 knockdown strongly inhibited the migration, proliferation and invasion ability of colon cancer cells. However, P4HA3 over-expression accelerated the abilities. Meanwhile, P4HA3 could promote subcutaneous tumorigenesis in nude mice in vivo. In addition, P4HA3 knockdown significantly decreased mesenchymal markers Vimentin, N-cadherin and Snail expression and increased epithelial marker E-cadherin expression. And conversely, over-expression of P4HA3 produced the opposite effects. In the current study, there was further evidence that down-regulating P4HA3 significantly reduced both TGF-β and its following molecules including p-Smad2 as well as p-Smad3. However, overexpression of P4HA3 showed the opposite effect. In conclusion, this study shows that P4HA3 promotes the human colon cancer growth and metastasis by affecting TGF-β/Smad signaling pathway. P4HA3 may become a new target for early diagnosis, treatment and prognosis assessment of colon cancer.

Chelerythrine inhibits the progression of glioblastoma by suppressing the TGFB1-ERK1/2/Smad2/3-Snail/ZEB1 signaling pathway

AIMS

Glioblastoma (GBM) is the most common and aggressive intracranial tumor with poor prognosis. A large majority of clinical chemotherapeutic agents cannot achieve the desired therapeutic effect. Chelerythrine (CHE), a natural component with multitudinous pharmacological functions, has been proven to have outstanding antitumor effects in addition to antibacterial, anti-inflammatory, and hypotensive effects. However, the anti-GBM effect of CHE has not been reported to date. The purpose of this paper is to observe the anti-GBM effect of CHE and further explore the related mechanism.

MATERIALS AND METHODS

GBM cell lines (U251 and T98G) and BALB/c nude mice were used in the experiments. Methyl thiazolyl tetrazolium (MTT) and clone formation assays were applied to detect the viability, proliferation and stemness of GBM cells. Flow cytometry was utilized to identify the effect of CHE on GBM apoptosis. Scratch and Transwell experiments reflected the migration and invasion of cells. In vivo, xenograft tumors were implanted subcutaneously in nude mice. The progression of tumors was assessed by ultrasound and magnetic resonance imaging. Finally, western blot, bioinformatics, and immunohistochemistry experiments were used to explore the molecular mechanisms in depth.

KEY FINDINGS

In vitro tests showed that CHE inhibited the proliferation, stemness, migration, and invasion of GBM cells and induced apoptosis. In vitro, CHE was observed to restrain the progression of xenograft tumors. We eventually proved that the cytotoxicity of CHE was relevant to the TGFB1-ERK1/2/Smad2/3-Snail/ZEB1 signaling pathway.

SIGNIFICANCE

CHE inhibited GBM progression by inhibiting the TGFB1-ERK1/2/Smad2/3-Snail/ZEB1 signaling pathway and is a potential chemotherapeutic drug for GBM.

Ghrelin attenuates transforming growth factor-β1-induced pulmonary fibrosis via the miR-125a-5p/Kruppel-like factor 13 axis

Pulmonary fibrosis is a severe condition with limited therapeutic options and characterized by increased fibroblast activation and progressive accumulation of extracellular matrix. Ghrelin, a gastrointestinal hormone, has been reported to possess protective roles in lung diseases including pulmonary fibrosis. However, the precise mechanisms underlying the protective effects of ghrelin remain unknown. The present study was designed to investigate the effects of ghrelin on transforming growth factor-β1 (TGF-β1)-induced pulmonary fibrosis in vitro and in vivo and the possible mechanism of action. It was found that ghrelin significantly attenuated TGF-β1-induced fibrotic responses in human lung fibroblast (IMR-90) cells and bleomycin (BLM)-induced fibrotic lung tissues. Meanwhile, ghrelin decreased the expressions of miR-125a-5p and phosphorylated smad2/3 and increased protein expressions of Kruppel-like factor 13 (KLF13) in vivo and in vitro. Ghrelin-induced anti-fibrotic effects and smad2/3 downregulation in TGF-β1-stimulated IMR-90 cells were markedly reversed by miR-125a-5p mimics and KLF13 siRNA. Furthermore, miR-125a-5p directly targeted KLF13 in IMR-90 cells. Our findings suggest that ghrelin attenuates TGF-β1-induced pulmonary fibrosis via the miR-125a-5p/KLF13 axis, which supports ghrelin as a new therapeutic agent against pulmonary fibrosis by antagonizing the TGF-β1 signaling pathway.

Wnt5A and TGFβ1 Converges through YAP1 Activity and Integrin Alpha v Up-Regulation Promoting Epithelial to Mesenchymal Transition in Ovarian Cancer Cells and Mesothelial Cell Activation

In this paper, we investigate whether Wnt5A is associated with the TGF-β1/Smad2/3 and Hippo-YAP1/TAZ-TEAD pathways, implicated in epithelial to mesenchymal transition (EMT) in epithelial ovarian cancer. We used 3D and 2D cultures of human epithelial ovarian cancer cell lines SKOV-3, OVCAR-3, CAOV-4, and different subtypes of human serous ovarian cancer compared to normal ovary specimens. Wnt5A showed a positive correlation with TAZ and TGFβ1 in high- and low-grade serous ovarian cancer specimens compared to borderline serous and normal ovaries. Silencing Wnt5A by siRNAs significantly decreased Smad2/3 activation and YAP1 expression and nuclear shuttling in ovarian cancer (OvCa) cells. Furthermore, Wnt5A was required for TGFβ1-induced cell migration and invasion. In addition, inhibition of YAP1 transcriptional activity by Verteporfin (VP) altered OvCa cell migration and invasion through decreased Wnt5A expression and inhibition of Smad2/3 activation, which was reverted in the presence of exogenous Wnt5A. We found that the activation of TGFβ1 and YAP1 nuclear shuttling was promoted by Wnt5A-induced integrin alpha v. Lastly, Wnt5A was implicated in activating human primary omental mesothelial cells and subsequent invasion of ovarian cancer cells. Together, we propose that Wnt5A could be a critical mediator of EMT-associated pathways.

Fibroblast growth factor-21 as a novel metabolic factor for regulating thrombotic homeostasis

Fibroblast growth factor-21 (FGF-21) performs a wide range of biological functions in organisms. Here, we report for the first time that FGF-21 suppresses thrombus formation with no notable risk of bleeding. Prophylactic and therapeutic administration of FGF-21 significantly improved the degree of vascular stenosis and reduced the thrombus area, volume and burden. We determined the antithrombotic mechanism of FGF-21, demonstrating that FGF-21 exhibits an anticoagulant effect by inhibiting the expression and activity of factor VII (FVII). FGF-21 exerts an antiplatelet effect by inhibiting platelet activation. FGF-21 enhances fibrinolysis by promoting tissue plasminogen activator (tPA) expression and activation, while inhibiting plasminogen activator inhibitor 1 (PAI-1) expression and activation. We further found that FGF-21 mediated the expression and activation of tPA and PAI-1 by regulating the ERK1/2 and TGF-β/Smad2 pathways, respectively. In addition, we found that FGF-21 inhibits the expression of inflammatory factors in thrombosis by regulating the NF-κB pathway.

Activation of TGF-β - SMAD2 signaling by IL-6 drives neuroendocrine differentiation of prostate cancer through p38MAPK

Neuroendocrine prostate cancer (NEPC) is an aggressive, androgen independent PCa and it is detected in patients undergoing androgen deprivation therapy (ADT). Interleukin-6 (IL-6) is a pleiotropic cytokine elevated in PCa patients promotes neuroendocrine differentiation (NED). In this study, PCa cells were differentiated with IL-6 in in-vitro to identify novel targets or signaling pathways associated with emergence of NEPC on deprivation of androgens. From the results, we observed an activation of TGF-β signaling pathway is altered through multiple proteins in differentiated LNCaP cells. Hence, we investigated the role of TGF-β axis in PCa cells differentiation. LNCaP cells treated with IL-6 in androgens deprived media release excess TGF-β ligand and this as conditioned media added to cells stimulated NED of PCa cells. TGF-β released by IL-6 stimulated cells activate p38MAPK through SMAD2 thereby promote NED. Inhibition of TGF-βRI and TGF-βRII signaling activation in LNCaP cells treated with IL-6 did not reversed the NED of cells, possibly due to the reason that the inhibition of TGF-β axis is further activating p38MAPK through SMAD independent manner in PCa cells. However, siRNA mediated knock down or inhibition p38MAPK inactivated TGF-β - SMAD axis in differentiating cells and attenuated NED of LNCaP cells. This result suggests that p38MAPK is the central node for receiving IL-6 signals and promotes NED of LNCaP cells in androgens free media. Remarkably, downregulation or inhibition of p38MAPK in NCI-H660 reversed NED characteristics as well as markers along with inactivation of SMAD2 whereas no effect observed in WPMY-1 normal prostate cells. Taken together these findings unveil that p38MAPK and its upstream regulators are potential targets to overcome the progression of NED of PCa and develop novel therapeutic measures along ADT for effective treatment of PCa.

Inhibition of TGF-β Signaling Attenuates Disuse-induced Trabecular Bone Loss After Spinal Cord Injury in Male Mice

Bone loss is one of the most common complications of immobilization after spinal cord injury (SCI). Whether transforming growth factor (TGF)-β signaling plays a role in SCI-induced disuse bone loss has not been determined. Thus, 16-week-old male mice underwent sham or spinal cord contusion injury to cause complete hindlimb paralysis. Five days later, 10 mg/kg/day control (IgG) or anti-TGF-β1,2,3 neutralizing antibody (1D11) was administered twice weekly for 4 weeks. Femurs were examined by micro-computed tomography (micro-CT) scanning and histology. Bone marrow (BM) supernatants were analyzed by enzyme-linked immunosorbent assay for levels of procollagen type 1 intact N-terminal propeptide (P1NP), tartrate-resistant acid phosphatase (TRAcP-5b), receptor activator of nuclear factor-kappa B ligand (RANKL), osteoprotegerin (OPG), and prostaglandin E2 (PGE2). Distal femoral micro-CT analysis showed that SCI-1D11 mice had significantly (P < .05) attenuated loss of trabecular fractional bone volume (123% SCI-1D11 vs 69% SCI-IgG), thickness (98% vs 81%), and connectivity (112% vs 69%) and improved the structure model index (2.1 vs 2.7). Histomorphometry analysis revealed that osteoclast numbers were lower in the SCI-IgG mice than in sham-IgG control. Biochemically, SCI-IgG mice had higher levels of P1NP and PGE2 but similar TRAcP-5b and RANKL/OPG ratio to the sham-IgG group. The SCI-1D11 group exhibited higher levels of P1NP but similar TRAcP-5b, RANKL/OPG ratio, and PGE2 to the sham-1D11 group. Furthermore, 1D11 treatment prevented SCI-induced hyperphosphorylation of tau protein in osteocytes, an event that destabilizes the cytoskeleton. Together, inhibition of TGF-β signaling after SCI protects trabecular bone integrity, likely by balancing bone remodeling, inhibiting PGE2 elevation, and preserving the osteocyte cytoskeleton.

Reduction of Smad2 caused by oxidative stress leads to necrotic death of hypertrophic chondrocytes associated with an endemic osteoarthritis

OBJECTIVE

The occurrence and development of an endemic OA, Kashin-Beck disease (KBD), is closely related to oxidative stress induced by free radicals. The aim of the study was to find the key signalling molecules or pathogenic factors as a potential treatment strategy for KBD.

METHODS

Real-time PCR and western blotting were performed to detect the mRNA and protein expression levels in cells and tissues. Immunohistochemical staining was assayed in rat models and human samples obtained from children. The type of cell death was identified by annexin V and propidium iodide staining with flow cytometry.

RESULTS

Oxidative stress decreased levels of Smad2 and Smad3 in hypertrophic chondrocytes both in vitro and in vivo. In the cartilage of KBD patients, the expression of Smad2 and Smad3 proteins in the middle and deep zone was significantly decreased with an observed full deletion in the deep zone of some samples. Reduction of Smad2 protein induced necrotic death of hypertrophic chondrocytes, while reduction of Smad3 protein induced apoptosis. The reduction of Smad2 protein was not accompanied by Smad3 protein reduction in hypertrophic chondrocyte necrosis. Furthermore, the reduction of Smad2 also impaired the construction of tissue-engineered cartilage in vitro.

CONCLUSION

These studies reveal that oxidative stress causes necrosis of hypertrophic chondrocytes by downregulating Smad2 protein, which increases the pathogenesis of KBD cartilage. The importance of Smad2 in the development of KBD provides a new potential target for the treatment of KBD.