The Role of Smad3 in the Realization of the Growth Potential of Different Types of Neural Progenitor Cells and the Secretory Function of Neuroglia.

The features of the participation of Smad3 in the functioning of neural stem cells (NSC), neuronal committed precursors (NCP), and neuroglial elements were studied in vitro. It was found that this intracellular signaling molecule enhances the clonogenic and proliferative activities of NCP and inhibits specialization of neuronal precursors. At the same time, Smad3 does not participate in the realization of the growth potential of NSC. With regard to the secretory function (production of neurotrophic growth factors) of neuroglial cells, the stimulating role of Smad3-mediated signaling was shown. These results indicate the promise of studying the possibility of using Smad3 as a fundamentally new target for neuroregenerative agents.

Galangin Promotes Tendon Repair Mediated by Tendon-Derived Stem Cells through Activating the TGF-ß1/Smad3 Signaling Pathway.

Tendon injury is a prevalent orthopedic disease that currently lacks effective treatment. Galangin (GLN) is a vital flavonoid found abundantly in galangal and is known for its natural activity. This study aimed to investigate the GLN-mediated molecular mechanism of tendon-derived stem cells (TDSCs) in tendon repair. The TDSCs were characterized using alkaline phosphatase staining, alizarin red S staining, oil red O staining, and flow cytometry. The effect of GLN treatment on collagen deposition was evaluated using Sirius red staining and quantitative (q)PCR, while a Western bot was used to assess protein levels and analyze pathways. Results showed that GLN treatment not only increased the collagen deposition but also elevated the mRNA expression and protein levels of multiple tendon markers like collagen type I alpha 1 (COL1A1), decorin (DCN) and tenomodulin (TNMD) in TDSCs. Moreover, GLN was also found to upregulate the protein levels of transforming growth factor ß1 (TGF-ß1) and p-Smad3 to activate the TGF-ß1/Smad3 signaling pathway, while GLN mediated collagen deposition in TDSCs was reversed by LY3200882, a TGF-ß receptor inhibitor. The study concluded that GLN-mediated TDSCs enhanced tendon repair by activating the TGF-ß1/Smad3 signaling pathway, suggesting a novel therapeutic option in treating tendon repair.

C-phycocyanin reinforces autophagy to block pulmonary fibrogenesis by inhibiting lncIAPF biogenesis.

Pulmonary fibrosis is a chronic and irreversible progressive lung disease caused by various factors, such as age and environmental pollution. With countries stepping into an aging society and the seriousness of environmental pollution caused by global industrialization, the incidence of pulmonary fibrosis is annually increasing. However, no effective drug is available for pulmonary fibrosis treatment. C-phycocyanin (C-PC), extracted from blue-green algae, has good water solubility and antioxidation. This study elucidated that C-PC reinforces autophagy to block pulmonary fibrogenesis by inhibiting long noncoding RNA (lncRNA) biogenesis in vivo and in vitro. Cleavage under targets and release using nuclease (CUT & RUN)-PCR, co-immunoprecipitation (Co-IP), and nuclear-cytoplasmic separation experiments clarified that C-PC blocked the nuclear translocation of activating transcription factor 3 (ATF3) to prevent the binding between ATF3 and transcription factor Smad3, thereby hindering lncIAPF transcription. Human antigen R (HuR) truncation experiment and RNA binding protein immunoprecipitation (RIP) were then performed to identify the binding domain with lncIAPF in the 244-322 aa of HuR. lncIAPF exerted its profibrogenic function through the binding protein HuR, a negative regulator of autophagy. In summary, C-PC promoted autophagy via down-regulating the lncIAPF-HuR-mediated signal pathway to alleviate pulmonary fibrosis, showing its potential as a drug for treating pulmonary fibrosis. Exploring how C-PC interacts with biological molecules will help us understand the mechanism of this drug and provide valuable target genes to design new drugs.

Anti-Inflammatory Effect of Atorvastatin and Rosuvastatin on Monosodium Urate-Induced Inflammation through IL-37/Smad3-Complex Activation in an In Vitro Study Using THP-1 Macrophages.

Objective: The pleiotropic effect of hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) is responsible for potent defense against inflammatory response. This study evaluated the inhibitory effects of HMG-CoA reductase inhibitors on the monosodium urate (MSU)-induced inflammatory response through the regulation of interleukin-37 (IL-37) expression. Methods: Serum was collected from patients with gout (n = 40) and from healthy controls (n = 30). The mRNA and protein expression of the target molecules IL-1ß, IL-37, caspase-1, and Smad3 were measured in THP-1 macrophages stimulated with MSU, atorvastatin, or rosuvastatin using a real-time quantitative polymerase chain reaction and Western blot assay. Transfection with IL-1ß or Smad3 siRNA in THP-1 macrophages was used to verify the pharmaceutical effect of statins in uric-acid-induced inflammation. Results: Serum IL-37 levels in gout patients were significantly higher than in controls (p < 0.001) and was associated with the serum uric acid level (r = 0.382, p = 0.008). THP-1 cells stimulated with MSU markedly induced IL-37 mRNA expression and the transition of IL-37 from the cytoplasm to the nucleus. Recombinant IL-37 treatment dose-dependently inhibited activation of caspase-1 and IL-1ß in MSU-induced inflammation. Atorvastatin and rosuvastatin attenuated caspase-1 activation and mature IL-1ß expression but augmented translocation of IL-37 from the cytoplasm to the nucleus. Atorvastatin and rosuvastatin induced phosphorylation of Smad3 in THP-1 cells treated with MSU crystals. Statins potently attenuated translocation of IL-37 from the cytoplasm to the nucleus in THP-1 macrophages transfected with Smad3 siRNA compared to cells with negative control siRNA. Conclusions: This study revealed that statins inhibit the MSU-induced inflammatory response through phosphorylated Smad3-mediated IL-37 expression in THP-1 macrophages.

Suppression of TGF-ß/Smad3 signaling pathway by Capparis spinosa and quercetin in a rat model of nonalcoholic steatohepatitis.

Objectives: Liver diseases, including non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH), pose significant global public health challenges. This study investigates the therapeutic effects of quercetin (QC), Capparis spinosa (CS), a QC and CS combination, and Saroglitazar (SARO) on NASH in a Wistar rat model. Materials and Methods: NASH was induced by a 42-day high-fat diet regimen in male Wistar rats. Post-induction, rats were divided into five groups receiving SARO, QC, CS, and CS+QC combination. We monitored changes in liver and body weights and evaluated the expression of genes associated with fatty acid biosynthesis (e.g., ACC and FAS), ß-oxidation (e.g., CPT1, PPAR α), inflammation (e.g., TNF-α and IL-6), and fibrosis (e.g., TGF-ß and COL1A), as well as protein expression levels of p-Smad2/3 and p-Smad3. Results: Treatment with QC+CS significantly decreased liver weight, body mass gain, and liver triglyceride (TG) compared to other treatments. The QC and CS combined therapy also resulted in a greater normalization of hepatic enzymatic activities, including decreases in ALT and AST levels, coupled with improvements in lipid profile indicated by decreased LDL-C and increased HDL-C concentrations, as compared to SARO and QC alone. Furthermore, this combined treatment significantly down-regulated the expression of TGF-ß, TNF-α, IL-6 genes, and Smad2/3 and Smad3 protein levels. Conclusion: Our study demonstrates that an interactive effect between QC and CS can effectively reduce liver fibrosis and steatosis by inhibiting the TGF-ß/Smad3 signaling pathway in a diet-induced model of nonalcoholic steatohepatitis and fibrosis in rats.

Decorin attenuates hypertrophic scar fibrosis via TGFß/Smad signalling.

The management of hypertrophic scars (HSs), characterized by excessive collagen production, involves various nonsurgical and surgical interventions. However, the absence of a well-defined molecular mechanism governing hypertrophic scarring has led to less-than-ideal results in clinical antifibrotic treatments. Therefore, our study focused on the role of decorin (DCN) and its regulatory role in the TGF-ß/Smad signalling pathway in the development of HSs. In our research, we observed a decrease in DCN expression within hypertrophic scar tissue and its derived cells (HSFc) compared to that in normal tissue. Then, the inhibitory effect of DCN on collagen synthesis was confirmed in Fc and HSFc via the detection of fibrosis markers such as COL-1 and COL-3 after the overexpression and knockdown of DCN. Moreover, functional assessments revealed that DCN suppresses the proliferation, migration and invasion of HSFc. We discovered that DCN significantly inhibits the TGF-ß1/Smad3 pathway by suppressing TGF-ß1 expression, as well as the formation and phosphorylation of Smad3. This finding suggested that DCN regulates the synthesis of collagen-based extracellular matrix and fibrosis through the TGF-ß1/Smad3 pathway.

Gemigliptin mitigates TGF-ß-induced renal fibrosis through FGF21-mediated inhibition of the TGF-ß/Smad3 signaling pathway.

Fibroblast growth factor 21 (FGF21), a well-known regulator of metabolic disorders, exhibits the potential to prevent renal fibrosis by negatively regulating the transforming growth factor ß (TGF-ß)/Smad3 signaling pathway. Gemigliptin and other dipeptidyl peptidase-4 inhibitors are frequently used for the management of patients with type 2 diabetes. However, the protective effect of gemigliptin against renal fibrosis, particularly its potential to upregulate the expression of FGF21, remains incompletely understood. This study assessed the renoprotective effects of gemigliptin against TGF-ß-induced renal fibrosis by enhancing the expression of FGF21 in the cultured human proximal tubular epithelial cell line HK-2. Treatment with FGF21 effectively prevented TGF-ß-induced renal fibrosis by attenuating the TGF-ß/Smad3 signaling pathway. Similarly, gemigliptin exhibited protective effects against TGF-ß-induced renal fibrosis by mitigating TGF-ß/Smad3 signaling through the upregulation of FGF21 expression. However, the protective effects of gemigliptin were blocked when FGF21 expression was knocked down in TGF-ß-treated HK-2 cells. These results indicate that gemegliptin has the potential to exhibit protective effects against TGF-ß-induced renal fibrosis by elevating FGF21 expression levels in cultured human proximal tubular epithelial cells.

Mechanistic insight into the hepatoprotective effect of Moringa oleifera Lam leaf extract and telmisartan against carbon tetrachloride-induced liver fibrosis: plausible roles of TGF-ß1/SMAD3/SMAD7 and HDAC2/NF-κB/PPARγ pathways.

The increasing prevalence and limited therapeutic options for liver fibrosis necessitates more medical attention. Our study aims to investigate the potential molecular targets by which Moringa oleifera Lam leaf extract (Mor) and/or telmisartan (Telm) alleviate carbon tetrachloride (CCl4)-induced liver fibrosis in rats. Liver fibrosis was induced in male Sprague-Dawley rats by intraperitoneal injection of 50% CCl4 (1 ml/kg) every 72 hours, for 8 weeks. Intoxicated rats with CCl4 were simultaneously orally administrated Mor (400 mg/kg/day for 8 weeks) and/or Telm (10 mg/kg/day for 8 weeks). Treatment of CCl4-intoxicated rats with Mor/Telm significantly reduced serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities compared to CCl4 intoxicated group (P < 0.001). Additionally, Mor/Telm treatment significantly reduced the level of hepatic inflammatory, profibrotic, and apoptotic markers including; nuclear factor-kappa B (NF-κB), tumor necrosis factor-alpha (TNF-α), transforming growth factor-ßeta1 (TGF-ß1), and caspase-3. Interestingly, co-treatment of CCl4-intoxicated rats with Mor/Telm downregulated m-RNA expression of histone deacetylase 2 (HDAC2) (71.8%), and reduced protein expression of mothers against decapentaplegic homolog 3 (p-SMAD3) (70.6%) compared to untreated animals. Mor/Telm regimen also elevated p-SMAD7 protein expression as well as m-RNA expression of peroxisome proliferator-activated receptor γ (PPARγ) (3.6 and 3.1 fold, respectively p < 0.05) compared to CCl4 intoxicated group. Histopathological picture of the liver tissue intoxicated with CCl4 revealed marked improvement by Mor/Telm co-treatment. Conclusively, this study substantiated the hepatoprotective effect of Mor/Telm regimen against CCl4-induced liver fibrosis through suppression of TGF-ß1/SMAD3, and HDAC2/NF-κB signaling pathways and up-regulation of SMAD7 and PPARγ expression.

GDF6 in gastric cancer upregulated by helicobacter pylori induces epithelial-mesenchymal translation via the TGF-ß/SMAD3 signaling pathway.

OBJECTIVE: To investigate the association between Helicobacter pylori infection and GDF6 expression in gastric cancer patients, and to determine its influence on prognosis and resistance to capecitabine. METHODS: Tumor and adjacent non-tumor tissues were collected from 148 gastric cancer patients who underwent surgery in our department from October 2019 to June 2022. Of these patients, 78 tested positive for Helicobacter pylori and 70 tested negative. Hematoxylin-eosin (HE) and immunofluorescence staining were utilized to quantify GDF6 expression in cancerous and adjacent tissues. Patient prognosis was monitored via follow-up. Western blotting analyzed GDF6 expression in common gastric cancer cell lines. HGC27 cells exhibiting high GDF6 expression and BGC823 cells with low expression were used to create GDF6-silenced and overexpressed cell lines. The impact of GDF6 on the proliferation, migration, invasion, and cloning abilities of gastric cancer cells was evaluated using the CCK-8 assay, scratch test, Transwell assay, and plate colony formation assay. Fluorescent quantitative PCR and Western blotting assessed the effects of GDF6 levels on epithelial-mesenchymal transition (EMT) and tumor cell stemness. RESULTS: GDF6 expression in gastric cancer tissues was significantly correlated with cancer grading and staging (P<0.05). Helicobacter pylori-positive tissues exhibited significantly higher GDF6 expression levels than negative samples (P<0.05). Kaplan-Meier survival analysis indicated that high GDF6 expression was associated with poor survival prognosis. Overexpressed GDF6 enhanced the proliferation, migration, and invasion abilities of gastric cancer cells, while silencing GDF6 yielded opposite results. Increased GDF6 expression upregulated TGF-ß expression and the phosphorylation levels of SMAD3, leading to an elevation in mesenchymal cell markers N-cadherin, vimentin, and a reduction in epithelial cell markers cytokeratins, E-cadherin. Moreover, high GDF6 levels contributed to increased resistance to capecitabine and enhanced the expression of tumor stem cell markers Nanog, Sox-2, Oct-4, CD44, amplifying tumor cell stemness. CONCLUSION: Helicobacter pylori infection is associated with increased GDF6 expression in gastric cancer tissue, correlating with poor survival prognosis. Elevated GDF6 expression promotes the proliferation, migration, and invasion abilities of gastric cancer cells, facilitates EMT via the TGF-ß/SMAD3 pathway, and intensifies cell stemness and capecitabine resistance. Consequently, GDF6 presents itself as a potential new target for gastric cancer treatment. DATA AVAILABILITY STATEMENT: The data that support the findings of this study are available from the corresponding author upon reasonable request.

MicroRNA­17­5p alleviates sepsis­related acute kidney injury in mice by modulating inflammation and apoptosis.

Septic acute kidney injury (AKI) is considered as a severe and frequent complication that occurs during sepsis. Mounting evidence has confirmed the pivotal pathogenetic roles of microRNA (miRNA or miR) in sepsis­induced AKI; however, the role of miRNAs and their underlying mechanisms in sepsis­induced AKI have not been entirely understood. The present study aimed to elucidate the functions of special miRNAs during sepsis­induced AKI and its underlying mechanism. First, a number of differently expressed miRNAs was identified based on the microarray dataset GSE172044. Subsequently, lipopolysaccharide (LPS) was used to induce AKI in mice, and the role of miR­17­5p on AKI was clarified. Finally, the related molecular mechanisms were further examined by western blotting and immunohistochemical analysis. MiR­17­5p was found to be continuously decreased and reached the bottom at h 24 after AKI in mice. Functionally, injection of agomiR­17­5p could observably improve renal injury and survival rate, as well as inhibit inflammatory cytokine production and renal cell apoptosis in mice after AKI. On the contrary, injection of antagomiR­17­5p aggravated LPS­induced renal injury, inflammation and apoptosis in mice after AKI. Moreover, transforming growth factor ß receptor 2 (TGFßR2) was identified as a direct target of miR­17­5p, and its downstream phosphorylated Smad3 was also suppressed by miR­17­5p upregulation. Taken together, these results demonstrated that miR­17­5p overexpression may exhibit a beneficial effect by attenuating LPS­induced inflammation and apoptosis via regulating the TGFßR2/TGF­ß/Smad3 signaling pathway, indicating that miR­17­5p could act as a potential target for sepsis treatment.

TGF-ß2 enhances glycolysis in chondrocytes via TßRI/p-Smad3 signaling pathway.

Chondrocytes rely heavily on glycolysis to maintain the metabolic homeostasis and cartilage matrix turnover. Glycolysis in chondrocytes is remodeled by diverse biochemical and biomechanical factors due to the sporty joint microenvironment. Transforming growth factor-ß2 (TGF-ß2), one of the most abundant TGF-ß superfamily members in chondrocytes, has increasingly attracted attention in cartilage physiology and pathology. Although previous studies have emphasized the importance of TGF-ß superfamily members on cell metabolism, whether and how TGF-ß2 modulates glycolysis in chondrocytes remains elusive. In the current study, we investigated the effects of TGF-ß2 on glycolysis in chondrocytes and explored the underlying biomechanisms. The results showed that TGF-ß2 could enhance glycolysis in chondrocytes by increasing glucose consumption, up-regulating liver-type ATP-dependent 6-phosphofructokinase (Pfkl) expression, and boosting lactate production. The TGF-ß2 signal entered chondrocytes via TGF-ß receptor type I (TßRI), and activated p-Smad3 signaling to regulate the glycolytic pathway. Subsequent experiments employing specific inhibitors of TßRI and p-Smad3 further substantiated the role of TGF-ß2 in enhancement of glycolysis via TßRI/p-Smad3 axis in chondrocytes. The results provide new understanding of the metabolic homeostasis in chondrocytes induced by TGF-ß superfamily and might shed light on the prevention and treatment of related osteoarticular diseases.

Polystyrene nanoplastics induce cardiotoxicity by upregulating HIPK2 and activating the P53 and TGF-ß1/Smad3 pathways.

Nanoplastics (NPs) pollution has become a global environmental problem, raising numerous health concerns. However, the cardiotoxicity of NPs exposure and the underlying mechanisms have been understudied to date. To address this issue, we comprehensively evaluated the cardiotoxicity of polystyrene nanoplastics (PS-NPs) in both healthy and pathological states. Briefly, mice were orally exposed to four different concentrations (0 mg/day, 0.1 mg/day, 0.5 mg/day, and 2.5 mg/day) of 100-nm PS-NPs for 6 weeks to assess their cardiotoxicity in a healthy state. Considering that individuals with underlying health conditions are more vulnerable to the adverse effects of pollution, we further investigated the cardiotoxic effects of PS-NPs on pathological states induced by isoprenaline. Results showed that PS-NPs induced cardiomyocyte apoptosis, cardiac fibrosis, and myocardial dysfunction in healthy mice and exacerbated cardiac remodeling in pathological states. RNA sequencing revealed that PS-NPs significantly upregulated homeodomain interacting protein kinase 2 (HIPK2) in the heart and activated the P53 and TGF-beta signaling pathways. Pharmacological inhibition of HIPK2 reduced P53 phosphorylation and inhibited the activation of the TGF-ß1/Smad3 pathway, which in turn decreased PS-NPs-induced cardiotoxicity. This study elucidated the potential mechanisms underlying PS-NPs-induced cardiotoxicity and underscored the importance of evaluating nanoplastics safety, particularly for individuals with pre-existing heart conditions.

Identification of proteins related to SIS3 by iTRAQ and PRM-based comparative proteomic analysis in cisplatin-induced acute kidney injury.

Background: Cisplatin is a commonly used nephrotoxic drug and can cause acute kidney injury (AKI). In the present study, isobaric tags for relative and absolute quantification (iTRAQ) and parallel reaction monitoring (PRM)-based comparative proteomics were used to analyze differentially expressed proteins (DEPs) to determine the key molecular mechanism in mice with cisplatin-induced AKI in the presence or absence of SIS3, a specific p-smad3 inhibitor, intervention. Methods: The cisplatin-induced AKI mouse model was established and treated with SIS3. We used iTRAQ to search for DEPs, PRM to verify key DEPs and combined Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) for bioinformatics analysis. We then assessed lipid deposition, malondialdehyde (MDA) and reactive oxygen species (ROS) and detected the expression of SREBF1, SCD1, CPT1A, PPARα and NDRG1 in vitro. Results: Proteomic analysis showed that the identified DEPs were mainly enriched in energy metabolism pathways, especially in lipid metabolism. When SIS3 was applied to inhibit the phosphorylation of Smad3, the expression of NDRG1 and fatty acid oxidation key proteins CPT1A and PPARα increased, the expression of lipid synthesis related proteins SREBF1 and SCD1 decreased and the production of lipid droplets, MDA and ROS decreased. Conclusion: SIS3 alleviates oxidative stress, reduces lipid accumulation and promotes fatty acid oxidation through NDRG1 in cisplatin-induced AKI. Our study provides a new candidate protein for elucidating the molecular mechanisms of fatty acid metabolism disorders in cisplatin-induced acute kidney injury.

Hederagenin improves renal fibrosis in diabetic nephropathy by regulating Smad3/NOX4/SLC7A11 signaling-mediated tubular cell ferroptosis.

Diabetic nephropathy (DN) is a common complication of diabetes, characterized by renal fibrosis and poor patient prognosis. Hederagenin (HDG) has shown promising improvement in chronic kidney disease (CKD) kidney fibrosis, but its mechanism in DN-induced kidney fibrosis remains unclear. In this study, a model of diabetic nephropathy (DN) in mice was induced by intraperitoneal injection of streptozocin (50 mg/kg), while in vitro, high glucose (25 mM) was used to induce HK2 cell damage, simulating tubular injury in DN kidneys. The improvement of HDG treatment intervention was evaluated by observing changes in renal function, pathological structural damage, and the expression of fibrosis-related proteins in renal tubular cells. The results demonstrate that HDG intervention alleviates renal dysfunction and pathological damage in DN mice, accompanied by reduced expression of fibrotic markers α-smooth muscle actin (α-SMA), fibronectin (FN) and Collagen-I. Mechanistically, this study found that HDG can inhibit ferroptosis and fibrosis induced by the ferroptosis inducer Erastin (1 µM) in renal tubular cells. Phosphorylation of Smad3 promotes ferroptosis in renal tubular cells. After using its specific inhibitor SIS3 (4 µM), the expression of downstream target protein NADPH oxidase 4 (NOX4) significantly decreases, while the level of glutathione peroxidase 4 (GPX4) is notably restored, mitigating ferroptosis. Smad3 overexpression attenuates the therapeutic effect of HDG on tubular cell fibrosis induced by high glucose. These results demonstrate HDG inhibits Smad3 phosphorylation, thereby reducing the expression of NOX4 and enhancing the expression of GPX4, ultimately attenuating ferroptosis induced renal fibrosis. These findings suggest that HDG offer therapeutic potential for DN renal fibrosis by targeting Smad3-mediated ferroptosis in renal tubular cells.

Sinomenine attenuates pulmonary fibrosis by downregulating TGF-ß1/Smad3, PI3K/Akt and NF-κB signaling pathways.

BACKGROUND: Since COVID-19 became a global epidemic disease in 2019, pulmonary fibrosis (PF) has become more prevalent among persons with severe infections, with IPF being the most prevalent form. In traditional Chinese medicine, various disorders are treated using Sinomenine (SIN). The SIN's strategy for PF defense is unclear. METHODS: Bleomycin (BLM) was used to induce PF, after which inflammatory factors, lung histological alterations, and the TGF-/Smad signaling pathway were assessed. By administering various dosages of SIN and the TGF- receptor inhibitor SB-431,542 to human embryonic lung fibroblasts (HFL-1) and A549 cells, we were able to examine proliferation and migration as well as the signaling molecules implicated in Epithelial-Mesenchymal Transition (EMT) and Extra-Cellular Matrix (ECM). RESULTS: In vivo, SIN reduced the pathological changes in the lung tissue induced by BLM, reduced the abnormal expression of inflammatory cytokines, and improved the weight and survival rate of mice. In vitro, SIN inhibited the migration and proliferation by inhibiting TGF-ß1/Smad3, PI3K/Akt, and NF-κB pathways, prevented the myofibroblasts (FMT) of HFL-1, reversed the EMT of A549 cells, restored the balance of matrix metalloenzymes, and reduced the expression of ECM proteins. CONCLUSION: SIN attenuated PF by down-regulating TGF-ß/Smad3, PI3K/Akt, and NF-κB signaling pathways, being a potential effective drug in the treatment of PF.

Role of hypoxia-mediated pyroptosis in the development of extending knee joint contracture in rats.

Joint contracture is one of the common diseases clinically, and joint capsule fibrosis is considered to be one of the most important pathological changes of joint contracture. However, the underlying mechanism of joint capsule fibrosis is still controversial. The present study aims to establish an animal model of knee extending joint contracture in rats, and to investigate the role of hypoxia-mediated pyroptosis in the progression of joint contracture using this animal model. 36 male SD rats were selected, 6 of which were not immobilized and were used as control group, while 30 rats were divided into I-1 group (immobilized for 1 week following 7 weeks of free movement), I-2 group (immobilized for 2 weeks following 6 weeks of free movement), I-4 group (immobilized for 4 weeks following 4 weeks of free movement), I-6 group (immobilized for 6 weeks following 2 weeks of free movement) and I-8 group (immobilized for 8 weeks) according to different immobilizing time. The progression of joint contracture was assessed by the measurement of knee joint range of motion, collagen deposition in joint capsule was examined with Masson staining, protein expression levels of HIF-1α, NLRP3, Caspase-1, GSDMD-N, TGF-ß1, α-SMA and p-Smad3 in joint capsule were assessed using western blotting, and the morphological changes of fibroblasts were observed by transmission electron microscopy. The degree of total and arthrogenic contracture progressed from the first week and lasted until the first eight weeks after immobilization. The degree of total and arthrogenic contracture progressed rapidly in the first four weeks after immobilization and then progressed slowly. Masson staining indicated that collagen deposition in joint capsule gradually increased in the first 8 weeks following immobilization. Western blotting analysis showed that the protein levels of HIF-1α continued to increase during the first 8 weeks of immobilization, and the protein levels of pyroptosis-related proteins NLRP3, Caspase-1, GSDMD-N continued to increase in the first 4 weeks after immobilization and then decreased. The protein levels of fibrosis-related proteins TGF-ß1, p-Smad3 and α-SMA continued to increase in the first 8 weeks after immobilization. Transmission electron microscopy showed that 4 weeks of immobilization induced cell membrane rupture and cell contents overflow, which further indicated the activation of pyroptosis. Knee extending joint contracture animal model can be established by external immobilization orthosis in rats, and the activation of hypoxia-mediated pyroptosis may play a stimulating role in the process of joint capsule fibrosis and joint contracture.

Brachyury promotes extracellular matrix synthesis through transcriptional regulation of Smad3 in nucleus pulposus.

Metabolic dysfunction of the extracellular matrix (ECM) is one of the primary causes of intervertebral disc degeneration (IVDD). Previous studies have demonstrated that the transcription factor Brachyury (Bry) has the potential to promote the synthesis of collagen II and aggrecan, while the specific mechanism is still unknown. In this study, we used a lipopolysaccharide (LPS)-induced model of nucleus pulposus cell (NPC) degeneration and a rat acupuncture IVDD model to elucidate the precise mechanism through which Bry affects collagen II and aggrecan synthesis in vitro and in vivo. First, we confirmed Bry expression decreased in degenerated human nucleus pulposus (NP) cells (NPCs). Knockdown of Bry exacerbated the decrease in collagen II and aggrecan expression in the lipopolysaccharide (LPS)-induced NPCs degeneration in vitro model. Bioinformatic analysis indicated that Smad3 may participate in the regulatory pathway of ECM synthesis regulated by Bry. Chromatin immunoprecipitation followed by quantitative polymerase chain reaction (ChIP-qPCR) and luciferase reporter gene assays demonstrated that Bry enhances the transcription of Smad3 by interacting with a specific motif on the promoter region. In addition, Western blot and reverse transcription-qPCR assays demonstrated that Smad3 positively regulates the expression of aggrecan and collagen II in NPCs. The following rescue experiments revealed that Bry-mediated regulation of ECM synthesis is partially dependent on Smad3 phosphorylation. Finally, the findings from the in vivo rat acupuncture-induced IVDD model were consistent with those obtained from in vitro assays. In conclusion, this study reveals that Bry positively regulates the synthesis of collagen II and aggrecan in NP through transcriptional activation of Smad3.NEW & NOTEWORTHY Mechanically, in the nucleus, Bry enhances the transcription of Smad3, leading to increased expression of Smad3 protein levels; in the cytoplasm, elevated substrate levels further lead to an increase in the phosphorylation of Smad3, thereby regulating collagen II and aggrecan expression. Further in vivo experiments provide additional evidence that Bry can alleviate IVDD through this mechanism.

MicroRNA-10 Family Promotes Renal Fibrosis through the VASH-1/Smad3 Pathway.

Renal fibrosis (RF) stands as a pivotal pathological process in the advanced stages of chronic kidney disease (CKD), and impeding its progression is paramount for delaying the advancement of CKD. The miR-10 family, inclusive of miR-10a and miR-10b, has been implicated in the development of various fibrotic diseases. Nevertheless, the precise role of miR-10 in the development of RF remains enigmatic. In this study, we utilized both an in vivo model involving unilateral ureteral obstruction (UUO) in mice and an in vitro model employing TGF-ß1 stimulation in HK-2 cells to unravel the mechanism underlying the involvement of miR-10a/b in RF. The findings revealed heightened expression of miR-10a and miR-10b in the kidneys of UUO mice, accompanied by a substantial increase in p-Smad3 and renal fibrosis-related proteins. Conversely, the deletion of these two genes led to a notable reduction in p-Smad3 levels and the alleviation of RF in mouse kidneys. In the in vitro model of TGF-ß1-stimulated HK-2 cells, the co-overexpression of miR-10a and miR-10b fostered the phosphorylation of Smad3 and RF, while the inhibition of miR-10a and miR-10b resulted in a decrease in p-Smad3 levels and RF. Further research revealed that miR-10a and miR-10b, through binding to the 3'UTR region of Vasohibin-1 (VASH-1), suppressed the expression of VASH-1, thereby promoting the elevation of p-Smad3 and exacerbating the progression of RF. The miR-10 family may play a pivotal role in RF.

Targeted PLK1 suppression through RNA interference mediated by high-fidelity Cas13d mitigates osteosarcoma progression via TGF-ß/Smad3 signalling.

Osteosarcoma is the most common primary bone malignancy in children and adolescents. Overexpression of polo-like kinase 1 (PLK1) is frequent in osteosarcoma and drives disease progression and metastasis, making it a promising therapeutic target. In this study, we explored PLK1 knockdown in osteosarcoma cells using RNA interference mediated by high-fidelity Cas13d (hfCas13d). PLK1 was found to be significantly upregulated in osteosarcoma tumour tissues compared to normal bone. sgRNA-mediated PLK1 suppression via hfCas13d transfection inhibited osteosarcoma cell proliferation, induced G2/M cell cycle arrest, promoted apoptosis, reduced cell invasion and increased expression of the epithelial marker E-cadherin. Proximity labelling by TurboID coupled with co-immunoprecipitation identified novel PLK1 interactions with Smad3, a key intracellular transducer of TGF-ß signalling. PLK1 knockdown impaired Smad2/3 phosphorylation and modulated TGF-ß/Smad3 pathway inactivation. Finally, in vivo delivery of hfCas13d vectors targeting PLK1 substantially attenuated osteosarcoma xenograft growth in nude mice. Taken together, this study highlights PLK1 as a potential therapeutic target and driver of disease progression in osteosarcoma. It also demonstrates the utility of hfCas13d-mediated gene knockdown as a strategy for targeted therapy. Further optimization of PLK1 suppression approaches may ultimately improve clinical outcomes for osteosarcoma patients.

Therapeutic targeting of PLK1 in TERT promoter-mutant hepatocellular carcinoma.

BACKGROUND: Hotspot mutations in the promoter of telomerase reverse transcriptase (TERT) gene are the most common genetic variants in hepatocellular carcinoma (HCC) and associated with poor prognosis of the disease. However, no drug was currently approved for treating TERT promoter mutation positive HCC patients. Here, we aim to explore the potential therapeutic strategy for targeting TERT promoter mutation in HCC. METHODS: The Liver Cancer Model Repository database was used for screening potential drugs to selectively suppress the growth of TERT promoter mutant HCC cells. RNA-seq, CRISPR-Cas9 technology and siRNA transfection were performed for mechanistic studies. Cell counting kit-8 (CCK8) assay and the xenograft tumour models were used for cell growth detection in vitro and in vivo, respectively. Cell apoptosis and cell cycle arrest were analysed by Annexin V-FITC staining and/or propidium iodide staining. RESULTS: PLK1 inhibitors were remarkably more sensitive to HCC cells harbouring TERT promoter mutation than wild-type cells in vitro and in vivo, which were diminished after TERT promoter mutation was edited to the wild-type nucleotide. Comparing the HCC cells with wild-type promoter of TERT, PLK1 inhibitors specifically downregulated Smad3 to regulate TERT for inducing apoptosis and G2/M arrest in TERT mutant HCC cells. Moreover, knockout of Smad3 counteracted the effects of PLK1 inhibitors in TERT mutant HCC cells. Finally, a cooperative effect of PLK1 and Smad3 inhibition was observed in TERT mutant cells. CONCLUSIONS: PLK1 inhibition selectively suppressed the growth of TERT mutant HCC cells through Smad3, thus contributed to discover a novel therapeutic strategy to treat HCC patients harbouring TERT promoter mutations. KEY POINTS: TERT promoter mutation confers sensitivity to PLK1 inhibitors in HCC. The selective growth inhibition of TERT mutant HCC cells induced by PLK1 inhibitor was mediated by Smad3. Combined inhibition of PLK1 and Smad3 showed a cooperative anti-tumor effect in TERT mutant HCC cells.