Inhibition of TGF-β1/Smad3 signaling by compound 5aa: A potential treatment for idiopathic pulmonary fibrosis

The incidence of idiopathic pulmonary fibrosis (IPF) has been steadily increasing each year, posing significant challenges in its treatment. In this study, we conducted the design and synthesis of 23 new inhibitors that specifically target the TGF-β1/Smad3 pathway. Initially, we employed a cell model of TGF-β-induced pulmonary fibrosis, using cell survival rate and HYP expression as indicators to identify the potent ingredient 5aa, which demonstrated significant anti-pulmonary fibrosis activity. Subsequently, we induced mice with bleomycin (BLM) to establish an experimental animal model of pulmonary fibrosis, and evaluated the pharmacodynamics of 5aa in vivo against pulmonary fibrosis. The alterations in HYP and collagen levels in BLM-induced pulmonary fibrosis mice were analyzed using ELISA and immunohistochemistry techniques. The results indicated that compound 5aa effectively suppressed the fibrotic response induced by TGF-β1, inhibited the expression of the fibrotic marker α-SMA, and hindered the EMT process in NIH3T3 cells. Additionally, oral administration of 5aa demonstrated significant therapeutic effects in a mouse model of IPF, comparable to the established drug Nintedanib. Moreover, compound 5aa exhibited higher bioavailability in vivo compared to Nintedanib. These collective outcomes suggest that 5aa holds promise as a potential inhibitor of TGF-β1/Smad3 signaling for the treatment of IPF.

TGF-β downstream of Smad3 and MAPK signaling antagonistically regulate the viability and partial epithelial-mesenchymal transition of liver progenitor cells

BACKGROUND

Liver progenitor cells (LPCs) are a subpopulation of cells that contribute to liver regeneration, fibrosis and liver cancer initiation under different circumstances.

RESULTS

By performing adenoviral-mediated transfection, CCK-8 analyses, F-actin staining, transwell analyses, luciferase reporter analyses and Western blotting, we observed that TGF-β promoted cytostasis and partial epithelial-mesenchymal transition (EMT) in LPCs. In addition, we confirmed that TGF-β activated the Smad and MAPK pathways, including the Erk, JNK and p38 MAPK signaling pathways, and revealed that TGFβ-Smad signaling induced growth inhibition and partial EMT, whereas TGFβ-MAPK signaling had the opposite effects on LPCs. We further found that the activity of Smad and MAPK signaling downstream of TGF-β was mutually restricted in LPCs. Mechanistically, we found that TGF-β activated Smad signaling through serine phosphorylation of both the C-terminal and linker regions of Smad2 and 3 in LPCs. Additionally, TGFβ-MAPK signaling inhibited the phosphorylation of Smad3 but not Smad2 at the C-terminus, and it reinforced the linker phosphorylation of Smad3 at T179 and S213. We then found that overexpression of mutated Smad3 at linker phosphorylation sites intensifies TGF-β-induced cytostasis and EMT, mimicking the effects of MAPK inhibition in LPCs, whereas mutation of Smad3 at the C-terminus caused LPCs to blunt TGF-β-induced cytostasis and partial EMT.

CONCLUSION

These results suggested that TGF-β downstream of Smad3 and MAPK signaling were mutually antagonistic in regulating the viability and partial EMT of LPCs. This antagonism may help LPCs overcome the cytostatic effect of TGF-β under fibrotic conditions and maintain partial EMT and progenitor phenotypes.

Myocardin regulates fibronectin expression and secretion from human pleural mesothelial cells

During the progression of pleural fibrosis, pleural mesothelial cells (PMCs) undergo a phenotype switching process known as mesothelial-mesenchymal transition (MesoMT). During MesoMT, transformed PMCs become myofibroblasts that produce increased extracellular matrix (ECM) proteins, including collagen and fibronectin (FN1) that is critical to develop fibrosis. Here, we studied the mechanism that regulates FN1 expression in myofibroblasts derived from human pleural mesothelial cells (HPMCs). We found that myocardin (Myocd), a transcriptional coactivator of serum response factor (SRF) and a master regulator of smooth muscle and cardiac muscle differentiation, strongly controls FN1 gene expression. Myocd gene silencing markedly inhibited FN1 expression. FN1 promoter analysis revealed that deletion of the Smad3-binding element diminished FN1 promoter activity, whereas deletion of the putative SRF-binding element increased FN1 promoter activity. Smad3 gene silencing decreased FN1 expression, whereas SRF gene silencing increased FN1 expression. Moreover, SRF competes with Smad3 for binding to Myocd. These results indicate that Myocd activates FN1 expression through Smad3, whereas SRF inhibits FN1 expression in HPMCs. In HPMCs, TGF-β induced Smad3 nuclear localization, and the proximity ligation signal between Myocd and Smad3 was markedly increased after TGF-β stimulation at nucleus, suggesting that TGF-β facilitates nuclear translocation of Smad3 and interaction between Smad3 and Myocd. Moreover, Myocd and Smad3 were coimmunoprecipitated and isolated Myocd and Smad3 proteins directly bound each other. Chromatin immunoprecipitation assays revealed that Myocd interacts with the FN1 promoter at the Smad3-binding consensus sequence. The results indicate that Myocd regulates FN1 gene activation through interaction and activation of the Smad3 transcription factor.NEW & NOTEWORTHY During phenotype switching from mesothelial to mesenchymal, pleural mesothelial cells (PMCs) produce extracellular matrix (ECM) proteins, including collagen and fibronectin (FN1), critical components in the development of fibrosis. Here, we found that myocardin, a transcriptional coactivator of serum response factor (SRF), strongly activates FN1 expression through Smad3, whereas SRF inhibits FN1 expression. This study provides insights about the regulation of FN1 that could lead to the development of novel interventional approaches to prevent pleural fibrosis.

A novel crosstalk between Nrf2 and Smad2/3 bridged by two nuanced Keap1 isoforms with their divergent effects on these distinct family transcription factors

The Keap1-Nrf2 signalling to transcriptionally regulate antioxidant response element (ARE)-driven target genes has been accepted as key redox-sensitive pathway governing a vast variety of cellular stresses during healthy survival and disease development. Herein, we identified two nuanced isoforms α and β of Keap1 in HepG2 cells, arising from its first and another in-frame translation starting codons, respectively. In identifying those differential expression genes monitored by Keap1α and/or Keap1β, an unusual interaction of Keap1 with Smad2/3 was discovered by parsing transcriptome sequencing, Keap1-interacting protein profiling and relevant immunoprecipitation data. Further examination validated that Smad2/3 enable physical interaction with Keap1, as well as its isoforms α and β, by both EDGETSD and DLG motifs in the linker regions between their MH1 and MH2 domains, such that the stability of Smad2/3 and transcriptional activity are enhanced with their prolonged half-lives and relevant signalling responses from the cytoplasmic to nuclear compartments. The activation of Smad2/3 by Keap1, Keap1α or Keap1β was much likely contributable to a coordinative or another competitive effect of Nrf2, particularly in distinct Keap1-based cellular responses to its cognate growth factor (i.e. TGF-β1) or redox stress (e.g. stimulated by tBHQ and DTT). Overall, this discovery presents a novel functional bridge crossing the Keap1-Nrf2 redox signalling and the TGF-β1-Smad2/3 pathways so as to coordinately regulate the healthy growth and development.

A lncRNA Dleu2-encoded peptide relieves autoimmunity by facilitating Smad3-mediated Treg induction

Micropeptides encoded by short open reading frames (sORFs) within long noncoding RNAs (lncRNAs) are beginning to be discovered and characterized as regulators of biological and pathological processes. Here, we find that lncRNA Dleu2 encodes a 17-amino-acid micropeptide, which we name Dleu2-17aa, that is abundantly expressed in T cells. Dleu2-17aa promotes inducible regulatory T (iTreg) cell generation by interacting with SMAD Family Member 3 (Smad3) and enhancing its binding to the Foxp3 conserved non-coding DNA sequence 1 (CNS1) region. Importantly, the genetic deletion of Dleu2-17aa in mice by start codon mutation impairs iTreg generation and worsens experimental autoimmune encephalomyelitis (EAE). Conversely, the exogenous supplementation of Dleu2-17aa relieves EAE. Our findings demonstrate an indispensable role of Dleu2-17aa in maintaining immune homeostasis and suggest therapeutic applications for this peptide in treating autoimmune diseases.

The multi-protective effect of IL-37-Smad3 against ox-LDL induced dysfunction of endothelial cells

Atherosclerosis is a lipid-driven inflammatory arterial disease, with one crucial factor is oxidized low-density lipoprotein (ox-LDL), which can induce endothelial dysfunction through endoplasmic reticulum stress (ERS). Interleukin-37 (IL-37) exerts vascular protective functions. This study aims to investigates whether IL-37 can alleviate ERS and autophagy induced by ox-LDL, therely potentialy treating atherosclerosis. We found that ox-LDL enhances the wound healing rate in Rat Coronary Artery Endothelial Cells (RCAECs) and IL-37 reduce the ox-LDL-induced pro-osteogenic response, ERS, and autophagy by binding to Smad3. In RCAECs treated with ox-LDL and recombinant human IL-37, the wound healing rate was mitigated. The expression of osteogenic transcription factors and proteins involved in the ERS pathway was reduced in the group pretreated with IL-37 and ox-LDL. However, these responses were not alleviated when Smads silenced. Electron microscopy revealed that the IL-37/Smad3 complex could suppress endoplasmic reticulum autophagy under ox-LDL stimulation. Thus, IL-37 might treat atherosclerosis through its multi-protective effect by binding Smad3.

Therapeutic potential for renal fibrosis by targeting Smad3-dependent noncoding RNAs

Renal fibrosis is a characteristic hallmark of chronic kidney disease (CKD) that ultimately results in renal failure, leaving patients with few therapeutic options. TGF-β is a master regulator of renal fibrosis and mediates progressive renal fibrosis via both canonical and noncanonical signaling pathways. In the canonical Smad signaling, Smad3 is a key mediator in tissue fibrosis and mediates renal fibrosis via a number of noncoding RNAs (ncRNAs). In this regard, targeting Smad3-dependent ncRNAs may offer a specific therapy for renal fibrosis. This review highlights the significance and innovation of TGF-β/Smad3-associated ncRNAs as biomarkers and therapeutic targets in renal fibrogenesis. In addition, the underlying mechanisms of these ncRNAs and their future perspectives in the treatment of renal fibrosis are discussed.

POH1 induces Smad3 deubiquitination and promotes lung cancer metastasis

Smad3 is the key mediator of TGF-β1-triggered signal transduction and the related biological responses, promoting cell invasion and metastasis in various cancers, including lung cancer. However, the deubiquitinase stabilizing Smad3 remains unknown. In this study, we present a paradigm in which POH1 is identified as a novel deubiquitinase of Smad3 that plays a tumor-promoting role in lung adenocarcinoma (LUAD) by regulating Smad3 stability. POH1 markedly increased Smad3 protein levels and prolonged its half-life. POH1 directly interacted and colocalized with Smad3, leading to the removal of poly-deubiquitination of Smad3. Functionally, POH1 facilitated cell proliferation, migration, and invasion by stabilizing Smad3. Importantly, POH1 also promoted liver metastasis of lung cancer cells. The protein levels of both POH1 and Smad3 were raised in the tumor tissues of patients with LUAD, which predicts poor prognosis. Collectively, we demonstrate that POH1 acts as an oncoprotein by enhancing TGF-β1/Smad3 signaling and TGF-β1-mediated metastasis of lung cancer.

Vascular smooth muscle cell-specific miRNA-214 deficiency alleviates simulated microgravity-induced vascular remodeling

The human cardiovascular system has evolved to accommodate the gravity of Earth. Microgravity during spaceflight has been shown to induce vascular remodeling, leading to a decline in vascular function. The underlying mechanisms are not yet fully understood. Our previous study demonstrated that miR-214 plays a critical role in angiotensin II-induced vascular remodeling by reducing the levels of Smad7 and increasing the phosphorylation of Smad3. However, its role in vascular remodeling evoked by microgravity is not yet known. This study aimed to determine the contribution of miR-214 to the regulation of microgravity-induced vascular remodeling. The results of our study revealed that miR-214 expression was increased in the forebody arteries of both mice and monkeys after simulated microgravity treatment. In vitro, rotation-simulated microgravity-induced VSMC migration, hypertrophy, fibrosis, and inflammation were repressed by miR-214 knockout (KO) in VSMCs. Additionally, miR-214 KO increased the level of Smad7 and decreased the phosphorylation of Smad3, leading to a decrease in downstream gene expression. Furthermore, miR-214 cKO protected against simulated microgravity induced the decline in aorta function and the increase in stiffness. Histological analysis showed that miR-214 cKO inhibited the increases in vascular medial thickness that occurred after simulated microgravity treatment. Altogether, these results demonstrate that miR-214 has potential as a therapeutic target for the treatment of vascular remodeling caused by simulated microgravity.

Hematopoietic Transcription Factor RUNX1 is Essential for Promoting Macrophage-Myofibroblast Transition in Non-Small-Cell Lung Carcinoma

Macrophage-myofibroblast transition (MMT) is a newly discovered pathway for mass production of pro-tumoral cancer-associated fibroblasts (CAFs) in non-small cell lung carcinoma (NSCLC) in a TGF-β1/Smad3 dependent manner. Better understanding its regulatory signaling in tumor microenvironment (TME) may identify druggable target for the development of precision medicine. Here, by dissecting the transcriptome dynamics of tumor-associated macrophage at single-cell resolution, a crucial role of a hematopoietic transcription factor Runx1 in MMT formation is revealed. Surprisingly, integrative bioinformatic analysis uncovers Runx1 as a key regulator in the downstream of MMT-specific TGF-β1/Smad3 signaling. Stromal Runx1 level positively correlates with the MMT-derived CAF abundance and mortality in NSCLC patients. Mechanistically, macrophage-specific Runx1 promotes the transcription of genes related to CAF signatures in MMT cells at genomic level. Importantly, macrophage-specific genetic deletion and systemic pharmacological inhibition of TGF-β1/Smad3/Runx1 signaling effectively prevent MMT-driven CAF and tumor formation in vitro and in vivo, representing a potential therapeutic target for clinical NSCLC.

Photobiomodulation inhibits the expression of chondroitin sulfate proteoglycans after spinal cord injury via the Sox9 pathway

Both glial cells and glia scar greatly affect the development of spinal cord injury and have become hot spots in research on spinal cord injury treatment. The cellular deposition of dense extracellular matrix proteins such as chondroitin sulfate proteoglycans inside and around the glial scar is known to affect axonal growth and be a major obstacle to autogenous repair. These proteins are thus candidate targets for spinal cord injury therapy. Our previous studies demonstrated that 810 nm photobiomodulation inhibited the formation of chondroitin sulfate proteoglycans after spinal cord injury and greatly improved motor function in model animals. However, the specific mechanism and potential targets involved remain to be clarified. In this study, to investigate the therapeutic effect of photobiomodulation, we established a mouse model of spinal cord injury by T9 clamping and irradiated the injury site at a power density of 50 mW/cm2 for 50 minutes once a day for 7 consecutive days. We found that photobiomodulation greatly restored motor function in mice and downregulated chondroitin sulfate proteoglycan expression in the injured spinal cord. Bioinformatics analysis revealed that photobiomodulation inhibited the expression of proteoglycan-related genes induced by spinal cord injury, and versican, a type of proteoglycan, was one of the most markedly changed molecules. Immunofluorescence staining showed that after spinal cord injury, versican was present in astrocytes in spinal cord tissue. The expression of versican in primary astrocytes cultured in vitro increased after inflammation induction, whereas photobiomodulation inhibited the expression of versican. Furthermore, we found that the increased levels of p-Smad3, p-P38 and p-Erk in inflammatory astrocytes were reduced after photobiomodulation treatment and after delivery of inhibitors including FR 180204, (E)-SIS3, and SB 202190. This suggests that Smad3/Sox9 and MAPK/Sox9 pathways may be involved in the effects of photobiomodulation. In summary, our findings show that photobiomodulation modulates the expression of chondroitin sulfate proteoglycans, and versican is one of the key target molecules of photobiomodulation. MAPK/Sox9 and Smad3/Sox9 pathways may play a role in the effects of photobiomodulation on chondroitin sulfate proteoglycan accumulation after spinal cord injury.

m6A-modified miR-143-3p inhibits epithelial mesenchymal transition in bronchial epithelial cells and extracellular matrix production in lung fibroblasts by targeting Smad3

BACKGROUND

Airway epithelial cells epithelial mesenchymal transition (EMT) and lung fibroblasts extracellular matrix (ECM) production are the key steps in airway remodeling. Our previous study demonstrated that miR-143-3p has the ability to impede airway smooth muscle cell proliferation and ECM deposition. However, the function of miR-143-3p in airway epithelial cells and lung fibroblasts remains unclear.

METHODS

Cell viability was determined using MTT method, while cell migration was evaluated through scratch assay. EMT and ECM proteins were detected by western blot, RT-qPCR, and ELISA. To determine the level of miR-143-3p m6A methylation, we employed the meRIP-qPCR assay. Additionally, the binding of miR-143-3p with Smad3 were projected by bioinformatics and validated by dual luciferase reporter assays.

RESULTS

It was discovered that the expression of miR-143-3p were lower in both asthma patients and TGF-β1-treated human bronchial epithelial 16HBE cells and human lung fibroblast HPF cells. Upregulation of miR-143-3p restrained 16HBE cell migration, and decreased EMT mesenchymal markers and increased epithelial markers. And upregulation of miR-143-3p impaired cell viability and ECM protein production in HPF cells. Mechanistically, interfering with METTL3 resulted in decreased m6A modification of miR-143-3p and led to lower levels of miR-143-3p. Moreover, miR-143-3p were verified to directly target and downregulate Smad3. Upregulation of Smad3 attenuated the effects of miR-143-3p on cell EMT and ECM production.

CONCLUSION

MiR-143-3p inhibits airway epithelial cell EMT as well as lung fibroblast ECM production by downregulating Smad3. Therefore, miR-143-3p may be a promising target to reduce airway remodeling in asthma.

Emetine dihydrochloride alleviated radiation-induced lung injury through inhibiting EMT

Radiation-induced lung injury (RILI), divided into early radiation pneumonia (RP) and late radiation-induced pulmonary fibrosis (RIPF), is a common serious disease after clinical chest radiotherapy or nuclear accident, which seriously threatens the life safety of patients. There has been no effective prevention or treatment strategy till now. Epithelial-mesenchymal transition (EMT) is a key step in the occurrence and development of RILI. In this study, we demonstrated that emetine dihydrochloride (EDD) alleviated RILI through inhibiting EMT. We found that EDD significantly attenuated EMT-related markers, reduced Smad3 phosphorylation expression after radiation. Then, for the first time, we observed EDD alleviated lung hyperaemia and reduced collagen deposit induced by irradiation, providing protection against RILI. Finally, it was found that EDD inhibited radiation-induced EMT in lung tissues. Our study suggested that EDD alleviated RILI through inhibiting EMT by blocking Smad3 signalling pathways. In summary, our results indicated that EDD is a novel potential radioprotector for RILI.

Paroxetine protects against bleomycin-induced pulmonary fibrosis by blocking GRK2/Smad3 pathway

G protein-coupled receptor kinase-2 (GRK2) is involved in TGF-β1-induced activation of lung fibroblasts, which could give rise to the pathogenesis of pulmonary fibrosis. Paroxetine (PRXT) serves as a selective GRK2 inhibitor which is widely used to treat anxiety and depression for several decades. However, whether PRXT could inhibit TGF-β1-induced activation of lung fibroblasts and combat bleomycin-induced pulmonary fibrosis remains unclear. Here, we investigated the effects of PRXT on pulmonary fibrosis in C57/BL6 caused by bleomycin as well as on the activation of murine primary lung fibroblasts stimulated with TGF-β1. The results demonstrated that PRXT markedly improved the pulmonary function and 21-day survival in bleomycin-induced mice. Meanwhile, PRXT significantly decreased collagen deposition, inflammation, and oxidative stress in lung tissues from bleomycin-induced mice. Furthermore, we found that PRXT could inhibit the protein and mRNA expression of GRK2 and Smad3 in lung tissues from bleomycin-induced mice. In vitro experiments also PRXT could inhibit cell activation and collagen synthesis in a concentration-dependent manner in TGF-β1-induced lung fibroblasts. In addition, we found that Smad3 overexpression by adenovirus transfection could offset anti-fibrotic and antioxidative effects from PRXT in TGF-β1-induced lung fibroblasts, which showed no effects on the protein expression of GRK2. In conclusion, PRXT mediates the inhibition of GRK2, which further blocks the transcription of Smad3 in TGF-β1-induced lung fibroblasts, providing an attractive therapeutic target for pulmonary fibrosis.

Effect of X-ray irradiation combined with PD-1 inhibitor treatment on lung tissue injury in mice

PURPOSE

To determine the effect of X-ray irradiation combined with PD-1 immune checkpoint inhibitor administration on lung tissue injury in a mouse model and its potential mechanism.

METHODS

In all, 20 C57BL/6J mice were randomly divided into four groups with five mice in each group: control group, PD-1 inhibitor group, irradiation group, and irradiation combined with PD-1 inhibitor group. Hematoxylin-eosin staining of the lung tissue was performed 30 days after the end of irradiation to evaluate the morphological and pathological changes in the tissue. Masson staining and analysis of hydroxyproline were used to evaluate the degree of pulmonary fibrosis. The levels of transforming growth factor-β1 (TGF-β1) and tumor necrosis factor α(TNF-α) were evaluated by Enzyme-Linked immunosorbent assay (ELISA). CD3+, CD4+, and CD8+ T lymphocytes in the lung tissue were detected by immunohistochemistry. The expression levels of TGF-β1, Smad3, cGAS, and STING in the lung tissue were evaluated by Western blotting.

RESULTS

The lung injury scores and pulmonary fibrosis indices in the irradiation group were higher than those in the control group. Meanwhile, lung pneumonia score, pulmonary fibrosis index, percentage of CD4 cells and expression of TGF-β1, p-Smad3, and STING in the lung tissue of mice in irradiation combined with PD-1 inhibitor group were higher than those in the other three groups.

CONCLUSION

Lung injury and pulmonary fibrosis were induced by whole chest X-ray irradiation in mice, and PD-1 inhibitor could aggravate lung injury and pulmonary fibrosis in mice. Thus, radiotherapy combined with PD-1 inhibitors may affect the immune inflammatory microenvironment in the lung tissues of mice by activating TGF-β1/Samd3 and cGAS/STING signaling pathways, thus aggravating lung tissue damage induced by radiation.

PSmad3+/Olig2- expression defines a subpopulation of gfap-GFP+/Sox9+ neural progenitors and radial glia-like cells in mouse dentate gyrus through embryonic and postnatal development

In mouse dentate gyrus, radial glia-like cells (RGLs) persist throughout life and play a critical role in the generation of granule neurons. A large body of evidence has shown that the combinatorial expression of transcription factors (TFs) defines cell types in the developing central nervous system (CNS). As yet, the identification of specific TFs that exclusively define RGLs in the developing mouse dentate gyrus (DG) remains elusive. Here we show that phospho-Smad3 (PSmad3) is expressed in a subpopulation of neural progenitors in the DG. During embryonic stage (E14-15), PSmad3 was predominantly expressed in gfap-GFP-positive (GFP+)/Sox2+ progenitors located at the lower dentate notch (LDN). As the development proceeds (E16-17), the vast majority of PSmad3+ cells were GFP+/Sox2+/Prox1low+/Ki67+ proliferative progenitors that eventually differentiated into granule neurons. During postnatal stage (P1-P6) PSmad3 expression was observed in GFP+ progenitors and astrocytes. Subsequently, at P14-P60, PSmad3 expression was found both in GFP+ RGLs in the subgranular zone (SGZ) and astrocytes in the molecular layer (ML) and hilus. Notably, PSmad3+ SGZ cells did not express proliferation markers such as PCNA and phospho-vimentin, suggesting that they are predominantly quiescent from P14 onwards. Significantly PSmad3+/GFP+ astrocytes, but not SGZ cells, co-expressed Olig2 and S100β. Together, PSmad3+/Olig2- expression serves as an exclusive marker for a specific subpopulation of GFP+ neural progenitors and RGLs in the mouse DG during both embryonic and postnatal period.

FoxO3 normalizes Smad3-induced arterial smooth muscle cell growth

Transition of arterial smooth muscle (ASM) from a quiescent, contractile state to a growth-promoting state is a hallmark of cardiovascular disease (CVD), a leading cause of death and disability in the United States and worldwide. While many individual signals have been identified as important mechanisms in this phenotypic conversion, the combined impact of the transcription factors Smad3 and FoxO3 in ASM growth is not known. The purpose of this study was to determine that a coordinated, phosphorylation-specific relationship exists between Smad3 and FoxO3 in the control of ASM cell growth. Using a rat in vivo arterial injury model and rat primary ASM cell lysates and fractions, validated low and high serum in vitro models of respective quiescent and growth states, and adenoviral (Ad-) gene delivery for overexpression (OE) of individual and combined Smad3 and/or FoxO3, we hypothesized that FoxO3 can moderate Smad3-induced ASM cell growth. Key findings revealed unique cellular distribution of Smad3 and FoxO3 under growth conditions, with induction of both nuclear and cytosolic Smad3 yet primarily cytosolic FoxO3; Ad-Smad3 OE leading to cytosolic and nuclear expression of phosphorylated and total Smad3, with almost complete reversal of each with Ad-FoxO3 co-infection in quiescent and growth conditions; Ad-FoxO3 OE leading to enhanced cytosolic expression of phosphorylated and total FoxO3, both reduced with Ad-Smad3 co-infection in quiescent and growth conditions; Ad-FoxO3 inducing expression and activity of the ubiquitin ligase MuRF-1, which was reversed with concomitant Ad-Smad3 OE; and combined Smad3/FoxO3 OE reversing both the pro-growth impact of singular Smad3 and the cytostatic impact of singular FoxO3. A primary takeaway from these observations is the capacity of FoxO3 to reverse growth-promoting effects of Smad3 in ASM cells. Additional findings lend support for reciprocal antagonism of Smad3 on FoxO3-induced cytostasis, and these effects are dependent upon discrete phosphorylation states and cellular localization and involve MuRF-1 in the control of ASM cell growth. Lastly, results showing capacity of FoxO3 to normalize Smad3-induced ASM cell growth largely support our hypothesis, and overall findings provide evidence for utility of Smad3 and/or FoxO3 as potential therapeutic targets against abnormal ASM growth in the context of CVD.

Persistent Hypoxia with Intermittent Aggravation Causes Imbalance in Smad3/Myocardin-Related Transcription Factor Signaling with Consequent Endothelial Senescence and Pulmonary Arterial Remodeling

Loss of Smad3 and the consequent activation of myocardin-related transcription factor (MRTF) are associated with vascular pathologies. This study aimed to examine the impact of persistent hypoxia with intermittent aggravation (PI hypoxia) on cellular senescence and pulmonary arterial remodeling mediated by the Smad3/MRTF imbalance. We examined the effects of PI hypoxia on the Smad3/MRTF pathway and cellular senescence using human pulmonary artery endothelial cells (HPAECs) and in vivo studies in rats. The senescent degree was evaluated using β-galactosidase staining, p16 quantitation and the measurement of senescence-associated secretory phenotype. Structural data in the pathological analysis of pulmonary artery remodeling were collected. Compared to the control, HPAECs and pulmonary tissue from rats exposed to PI hypoxia showed a significantly higher senescent degree, lower expression of Smad3, and higher MRTF levels. The overexpression of Smad3 significantly mitigated HPAECs senescence in vitro. Further, treatment with CCG-203971, which inhibits MRTF, increased Smad3 levels and reduced β-galactosidase positive cells in rat lung tissue. This intervention also alleviated PI hypoxia-induced pathological changes, including remodeling indices of pulmonary arterial thickening, muscularization, and collagen formation. In conclusion, imbalanced Smad3/MRTF signaling is linked to PI hypoxia-induced senescence and pulmonary arterial remodeling, making it a potential therapeutic target for patients with sleep apnea and chronic obstructive pulmonary disease.

Oxymatrine relieves high-fructose/fat-induced obesity via reprogramming the activity of lipid metabolism-related enhancer

Introduction

Emerging evidence demonstrates that the high-fructose and high-fat diet (HFHF) induced obesity and fatty liver disease has become one of the most common metabolic disorders worldwide. Therefore, innovative investigations on compounds targeting obesity and fatty liver diseases are urgently needed.

Methods

The high-throughput natural compounds screen was performed to screen the important compounds. A rat HFHF model was constructed, the regulatory function of Oxymatrine in HFHF-induced obesity was further explored.

Results

We identified Oxymatrine, a natural compound extracted from Sophora flavescens, showed a potential compacity in high-fat diet-induced fatty liver disease. We found that oxymatrine significantly inhibited HFHF-induced obesity using a rat HFHF model. Additionally, we found that oxymatrine altered the enhancer landscape of subcutaneous adipose tissues by ChIP-seq analysis using antibodies against the H3K27ac histone modification. Motif enrichment analysis showed the Smad motif was significantly enriched in enhancers altered post-oxymatrine treatment. Further chromatin immunoprecipitation-quantitative PCR (ChIP-qPCR) analysis and luciferase reporter assays showed oxymatrine alters the binding of Smad3 on the enhancer regions of B-cell lymphoma 2 (Bcl2) and the enhancer activity of Bcl2.

Discussion

Together, our study highlighted oxymatrine could suppress high-fructose and high-fat diet-induced obesity by inhibiting the suppressor of mothers against decapentaplegic 3 (Smad3) binding on obesity-related enhancers.

Wall Shear Stress Reduction Activates Angiotensin II to Facilitate Aneurysmal Subarachnoid Hemorrhage in Intracranial Aneurysms Through MicroRNA-29/The Growth Factor-Beta Receptor Type II/Smad3 Axis

OBJECTIVE

We tried to broaden our knowledge of the possible role of wall shear stress (WSS) in the occurrence of intracranial aneurysms (IAs).

METHODS

Genes implicated in IAs and genes related to WSS were predicted through in silico analysis. Rat models of IAs were established, in which the expression patterns of angiotensin II (Ang II) were characterized, and WSS was assessed. Vascular endothelial cells isolated from rats bearing IAs were treated with microRNA-29 (miR-29) mimic/inhibitor, small interfering RNA-TGF-β receptor type II (TGFBR2)/overexpressed TGFBR2, Ang II, or angiotensin-converting enzyme (ACE) inhibitor. Then, the endothelial-to-mesenchymal transition (EndMT) was evaluated by flow cytometry. Finally, the volume of IAs and risk of subarachnoid hemorrhage were analyzed in vivo in response to miR-29 gain of function.

RESULTS

WSS was decreased in the IA bearing arteries, which showed a positive correlation with ACE and Ang II in the vascular tissues of IA rats. Reduced miR-29 and increased ACE, Ang II, and TGFBR2 were detected in the vascular tissues of IA rats. Ang II inhibited miR-29, which targeted TGFBR2. Downregulated TGFBR2 was accompanied by suppression of Smad3 phosphorylation. Through impairing miR-29-dependent inhibition of TGFBR2, Ang II enhanced EndMT. In vivo data confirmed that treatment of miR-29 agomir delayed the formation of IA and decreased the risk of subarachnoid hemorrhage.

CONCLUSIONS

The current study provided evidence that WSS reduction could activate Ang II, reduce miR-29 expression, and activate the TGFBR2/Smad3 axis, thus promoting EndMT and accelerating the progression of IAs.

Smad3 Mediates Diabetic Dyslipidemia and Fatty Liver in db/db Mice by Targeting PPARδ

Transforming growth factor-β (TGF-β)/Smad3 signaling has been shown to play important roles in fibrotic and inflammatory diseases. However, the role of Smad3 in dyslipidemia and non-alcoholic fatty liver disease (NAFLD) in type 2 diabetes remains unclear, and whether targeting Smad3 has a therapeutic effect on these metabolic abnormalities remains unexplored. These topics were investigated in this study in Smad3 knockout (KO)-db/db mice and by treating db/db mice with a Smad3-specific inhibitor SIS3. Compared to Smad3 wild-type (WT)-db/db mice, Smad3 KO-db/db mice were protected against dyslipidemia and NAFLD. Similarly, treatment of db/db mice with SIS3 at week 4 before the onset of type 2 diabetes until week 12 was capable of lowering blood glucose levels and improving diabetic dyslipidemia and NAFLD. In addition, using RNA-sequencing, the potential Smad3-target genes related to lipid metabolism was identified in the liver tissues of Smad3 KO/WT mice, and the regulatory mechanisms were investigated. Mechanistically, we uncovered that Smad3 targeted peroxisome proliferator-activated receptor delta (PPARδ) to induce dyslipidemia and NAFLD in db/db mice, which was improved by genetically deleting and pharmacologically inhibiting Smad3.

Effect of aging on the formation and growth of colonic epithelial organoids by changes in cell cycle arrest through TGF-β-Smad3 signaling

BACKGROUND

This study aimed to investigate how aging alters the homeostasis of the colonic intestinal epithelium and regeneration after tissue injury using organoid models and to identify its underlying molecular mechanism.

METHODS

To investigate aging-related changes in the colonic intestinal epithelium, we conducted organoid cultures from old (older than 80 weeks) and young (6-10 weeks) mice and compared the number and size of organoids at day 5 of passage 0 and the growth rate of organoids between the two groups.

RESULTS

The number and size of organoids from old mice was significantly lower than that from young mice (p < 0.0001) at day 5 of passage 0. The growth rate of old-mouse organoids from day 4 to 5 of passage 0 was significantly slower than that of young-mouse organoids (2.21 times vs. 1.16 times, p < 0.001). RNA sequencing showed that TGF-β- and cell cycle-associated genes were associated with the aging effect. With regard to mRNA and protein levels, Smad3 and p-Smad3 in the old-mouse organoids were markedly increased compared with those in the young-mouse organoids. Decreased expression of ID1, increased expression of p16^INK4a, and increased cell cycle arrest were observed in the old mouse-organoids. Treatment with SB431542, a type I TGF-β receptor inhibitor, significantly increased the formation and growth of old-mouse organoids, and TGF-β1 treatment markedly suppressed the formation of young-mouse organoids. In the acute dextran sulfate sodium-colitis model and its organoid experiments, the colonic epithelial regeneration after tissue injury in old mice was significantly decreased compared with young mice.

CONCLUSIONS

Aging reduced the formation ability and growth rate of colonic epithelial organoids by increasing cell cycle arrest through TGF-β-Smad3-p16^INK4a signaling.

T-2 toxin-induced chondrocyte apoptosis contributes to growth plate damage through Smad2 and Smad3 signaling

The growth plate cartilage is one of the most common areas that Kashin-Beck Disease attacks. However, the exact mechanism of growth plate damage remains unclear. Here, we demonstrated that Smad2 and Smad3 were closely associated with the differentiation of chondrocytes. Reduction of Smad2 and Smad3 were found both in T-2 toxin-induced human chondrocytes in vitro and in T-2 toxin-induced rat growth plate in vivo. Blunting Smad2 or Smad3 both strikingly induced human chondrocytes apoptosis, implying a plausible signaling pathway to clarify the mechanism of T-2 toxin-induced oxidative damage. Furthermore, decreased Smad2 and Smad3 were also observed in the growth plates of KBD children. Collectively, our findings clearly illustrated that T-2 toxin-induced chondrocyte apoptosis contributes to growth plate damage through Smad2 and Smad3 signaling, which refines the pathogenesis of endemic osteoarthritis and provides two potential targets for the prevention and repairment of endemic osteoarthritis.

Synergism of calycosin and bone marrow-derived mesenchymal stem cells to combat podocyte apoptosis to alleviate adriamycin-induced focal segmental glomerulosclerosis

BACKGROUND

Bone marrow-derived mesenchymal stem cells (MSCs) show podocyte-protective effects in chronic kidney disease. Calycosin (CA), a phytoestrogen, is isolated from Astragalus membranaceus with a kidney-tonifying effect. CA preconditioning enhances the protective effect of MSCs against renal fibrosis in mice with unilateral ureteral occlusion. However, the protective effect and underlying mechanism of CA-pretreated MSCs (MSCs^CA) on podocytes in adriamycin (ADR)-induced focal segmental glomerulosclerosis (FSGS) mice remain unclear.

AIM

To investigate whether CA enhances the role of MSCs in protecting against podocyte injury induced by ADR and the possible mechanism involved.

METHODS

ADR was used to induce FSGS in mice, and MSCs, CA, or MSCs^CA were administered to mice. Their protective effect and possible mechanism of action on podocytes were observed by Western blot, immunohistochemistry, immunofluorescence, and real-time polymerase chain reaction. In vitro, ADR was used to stimulate mouse podocytes (MPC5) to induce injury, and the supernatants from MSC-, CA-, or MSCs^CA-treated cells were collected to observe their protective effects on podocytes. Subsequently, the apoptosis of podocytes was detected in vivo and in vitro by Western blot, TUNEL assay, and immunofluorescence. Overexpression of Smad3, which is involved in apoptosis, was then induced to evaluate whether the MSCs^CA-mediated podocyte protective effect is associated with Smad3 inhibition in MPC5 cells.

RESULTS

CA-pretreated MSCs enhanced the protective effect of MSCs against podocyte injury and the ability to inhibit podocyte apoptosis in ADR-induced FSGS mice and MPC5 cells. Expression of p-Smad3 was upregulated in mice with ADR-induced FSGS and MPC5 cells, which was reversed by MSC^CA treatment more significantly than by MSCs or CA alone. When Smad3 was overexpressed in MPC5 cells, MSCs^CA could not fulfill their potential to inhibit podocyte apoptosis.

CONCLUSION

MSCs^CA enhance the protection of MSCs against ADR-induced podocyte apoptosis. The underlying mechanism may be related to MSCs^CA-targeted inhibition of p-Smad3 in podocytes.

FOXO3 regulates Smad3 and Smad7 through SPON1 circular RNA to inhibit idiopathic pulmonary fibrosis

Forkhead box protein O3 (FOXO3) has good inhibition ability toward fibroblast activation and extracellular matrix, especially for the treatment of idiopathic pulmonary fibrosis. How FOXO3 regulates pulmonary fibrosis remains unclear. In this study, we reported that FOXO3 had binding sequences with F-spondin 1 (SPON1) promoter, which can activate its transcription and selectively promote the expression of SPON1 circRNA (circSPON1) but not mRNA expression. We further demonstrated that circSPON1 was involved in the extracellular matrix deposition of HFL1. In the cytoplasm, circSPON1 directly interacted with TGF-β1-induced Smad3 and inhibited the activation of fibroblasts by inhibiting nuclear translocation. Moreover, circSPON1 bound to miR-942-5p and miR-520f-3p that interfered with Smad7 mRNA and promoted Smad7 expression. This study revealed the mechanism of FOXO3-regulated circSPON1 in the development of pulmonary fibrosis. Potential therapeutic targets and new insights into the diagnosis and treatment of idiopathic pulmonary fibrosis based on circRNA were also provided.

Smad3-mediated lncRNA HSALR1 enhances the non-classic signalling pathway of TGF-β1 in human bronchial fibroblasts by binding to HSP90AB1

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is one of the diseases with high mortality and morbidity with complex pathogenesis. Airway remodeling is an unavoidable pathological characteristic. However, the molecular mechanisms of airway remodeling are incompletely defined.

METHODS

lncRNAs highly correlated with transforming growth factor beta 1(TGF-β1) expression were chosen, the lncRNA ENST00000440406 (named HSP90AB1 Assoicated LncRNA 1, HSALR1) was chosen for further functional experiments. Dual luciferase and ChIP assay were used to detect the upstream of HSALR1, transcriptome sequencing, Cck-8, Edu, cell proliferation, cell cycle assay, and WB detection of pathway levels confirmed the effect of HSALR1 on fibroblast proliferation and phosphorylation levels of related pathways. Mice was infected with adeno-associated virus (AAV) to express HSALR1 by intratracheal instillation under anesthesia and was exposure to cigarette smoke, then mouse lung function was performed and the pathological sections of lung tissues were analyzed.

RESULTS

Herein, lncRNA HSALR1 was identified as highly correlated with the TGF-β1 and mainly expressed in human lung fibroblasts. HSALR1 was induced by Smad3 and promoted fibroblasts proliferation. Mechanistically, it could directly bind to HSP90AB1 protein, and acted as a scaffold to stabilize the binding between Akt and HSP90AB1 to promote Akt phosphorylation. In vivo, mice expressed HSALR1 by AAV was exposure to cigarette smoke (CS) for COPD modeling. We found that lung function was worse and airway remodeling was more pronounced in HSLAR1 mice compare to wild type (WT) mice.

CONCLUSION

Our results suggest that lncRNA HSALR1 binds to HSP90AB1 and Akt complex component, and enhances activity of the TGF-β1 smad3-independent pathway. This finding described here suggest that lncRNA can participate in COPD development, and HSLAR1 is a promising molecular target of COPD therapy.

Tectorigenin relieved sepsis-induced myocardial ferroptosis by inhibiting the expression of Smad3

Background

Myocardial injury is a serious consequence of sepsis that contributes to high rates of death. Currently, the pathophysiology of cardiac damage in sepsis is still unknown, and treatment approaches are limited.

Methods

The sepsis mouse model was established inducing by Lipopolysaccharide (LPS) in vivo and Tectorigenin was pretreated to explore whether it contributed to alleviated myocardial injury. Hematoxylin-eosin (HE) stain was employed to evaluate the myocardial injury severity. TUNEL assay measured the number of apoptosis cells and the levels of B-cell lymphoma-2 associated X (Bax) and Cleaved Caspase-3 were assessed by western blot. The contents of iron and related ferroptosis molecules (acyl-CoA synthetase long-chain family (ACSL4), Glutathione Peroxidase 4 (GPX4)) were assessed. Then, interleukin-1β (IL-1β), IL-18, IL-6, tumor necrosis factor-α (TNF-α), and other inflammatory-related cytokines were detected by ELISA. The expression of the mother against decapentaplegic homolog 3 (Smad3) in heart tissues was evaluated by western blot and immunofluorescence.

Results

Tectorigenin alleviated myocardial dysfunction and myofibrillar disruption in LPS-related sepsis groups. Tectorigenin ameliorated cardiomyocyte apoptosis and myocardial ferroptosis in LPS-stimulated sepsis mice. Tectorigenin reduced inflammatory-relevant cytokines in the cardiac tissues of LPS stimuli mice. In addition, we further confirm that Tectorigenin relieved myocardial ferroptosis by inhibiting the expression of Smad3.

Discussion

Tectorigenin ameliorates myocardial damage stimulated by LPS and this effect exerts by inhibiting ferroptosis and the inflammation of the myocardium. Furthermore, the inhibitory effect of Tectorigenin on ferroptosis may deregulate Smad3 expression. Taken together, Tectorigenin may be a viable method for alleviating myocardial damage in sepsis.

Estrogen receptor β attenuates renal fibrosis by suppressing the transcriptional activity of Smad3

Renal fibrosis (RF) is a common pathway leading to chronic kidney disease (CKD), which lacks effective treatment. While estrogen receptor beta (ERβ) is known to be present in the kidney, its role in RF remains unclear. The present study aimed to investigate the role and underlying mechanism of ERβ during RF progression in patients and animal models with CKD. We found that ERβ was highly expressed in the proximal tubular epithelial cells (PTECs) in healthy kidneys but its expression was largely lost in patients with immunoglobin A nephropathy (IgAN) and in mice with unilateral ureter obstruction (UUO) and subtotal nephrectomy (5/6Nx). ERβ deficiency markedly exacerbated, whereas ERβ activation by WAY200070 and DPN attenuated RF in both UUO and 5/6Nx mouse models, suggesting a protective role of ERβ in RF. In addition, ERβ activation inhibited TGF-β1/Smad3 signaling, while loss of renal ERβ was associated with overactivation of the TGF-β1/Smad3 pathway. Furthermore, deletion or pharmacological inhibition of Smad3 prevented the loss of ERβ and RF. Mechanistically, activation of ERβ competitively inhibited the association of Smad3 with the Smad-binding element, thereby downregulating the transcription of the fibrosis-related genes without altering Smad3 phosphorylation in vivo and in vitro. In conclusion, ERβ exerts a renoprotective role in CKD by blocking the Smad3 signaling pathway. Thus, ERβ may represent as a promising therapeutic agent for RF.

Canagliflozin alleviates high glucose-induced peritoneal fibrosis via HIF-1α inhibition

The cardioprotective effects of sodium-glucose cotransporter type 2 (SGLT2) inhibitors have been demonstrated in many studies. However, their benefits for end-stage kidney disease patients, particularly those on peritoneal dialysis, remain unclear. SGLT2 inhibition has shown peritoneal protective effects in some studies, but the mechanisms are still unknown. Herein, we investigated the peritoneal protective mechanisms of Canagliflozin in vitro by simulating hypoxia with CoCl₂ in human peritoneal mesothelial cells (HPMCs) and rats by intraperitoneal injection of 4.25% peritoneal dialysate simulating chronic high glucose exposure. CoCl₂ hypoxic intervention significantly increased HIF-1α abundance in HPMCs, activated TGF-β/p-Smad3 signaling, and promoted the production of fibrotic proteins (Fibronectin, COL1A2, and α-SMA). Meanwhile, Canagliflozin significantly improved the hypoxia of HPMCs, decreased HIF-1α abundance, inhibited TGF-β/p-Smad3 signaling, and decreased the expression of fibrotic proteins. Five-week intraperitoneal injection of 4.25% peritoneal dialysate remarkably increased peritoneal HIF-1α/TGF-β/p-Smad3 signaling and promoted peritoneal fibrosis and peritoneal thickening. At the same time, Canagliflozin significantly inhibited the HIF-1α/TGF-β/p-Smad3 signaling, prevented peritoneal fibrosis and peritoneal thickening, and improved peritoneal transportation and ultrafiltration. High glucose peritoneal dialysate increased the expression of peritoneal GLUT1, GLUT3 and SGLT2, all of which were inhibited by Canagliflozin. In conclusion, we showed that Canagliflozin could improve peritoneal fibrosis and function by ameliorating peritoneal hypoxia and inhibiting the HIF-1α/TGF-β/p-Smad3 signaling pathway, providing theoretical support for the clinical use of SGLT2 inhibitors in patients on peritoneal dialysis.

Montelukast prevents mice against carbon tetrachloride- and methionine-choline deficient diet-induced liver fibrosis: Reducing hepatic stellate cell activation and inflammation

AIMS

Montelukast is an antagonist of cysteinyl leukotriene receptor 1 (CysLTR1) that protects against inflammation and oxidative stress. However, the function of montelukast in liver fibrosis remains unknown. In this study, we examined whether the pharmacological inhibition of CysLTR1 could protect mice against hepatic fibrosis.

MATERIALS AND METHODS

Carbon tetrachloride (CCl₄) and methionine-choline deficient (MCD) diet models were used in this study. The expression of CysLTR1 in liver were detected by RT-qPCR and Western blot analysis. Liver hydroxyproline levels, fibrotic genes expression, serum biochemical indexes and inflammatory factors were used to evaluate the effect of montelukast on liver fibrosis, injury, and inflammation. In vitro, we used the RT-qPCR and Western blot analysis to assess CysLTR1 in mouse primary hepatic stellate cell (HSC) and human LX-2 cell line. The role of montelukast on HSC activation and the underlying mechaisms were determined using RT-qPCR analysis, Western blot and immunostaining assays.

KEY FINDINGS

Chronic stimulation from CCl₄ and MCD diet upregulated the mRNA and protein levels of CysLTR1 in the liver. Pharmacological inhibition of CysLTR1 by montelukast ameliorated liver inflammation and fibrosis in both models. Mechanistically, montelukast suppressed HSC activation by targeting the TGFβ/Smad pathway in vitro. The hepatoprotective effect of montelukast was also associated with reduced liver injury and inflammation.

SIGNIFICANCE

Montelukast suppressed CCl₄- and MCD-induced chronic hepatic inflammation and liver fibrosis. CysLTR1 might be a therapeutic target for treating liver fibrosis.

Mediator1 involved in functional integration of Smad3 and Notch1 promoting enamel mineralization

Enamel hypoplasia is a tooth development defection due to the disruption of enamel matrix mineralization, manifesting as chalky white phenotype. Multiple genes may be involved in this tooth agenesis. It has been proved that ablation of coactivator Mediator1 (Med1) switches the cell fate of dental epithelia, resulting in abnormal tooth development via Notch1 signaling. Smad3 (-/-) mice displays the similar chalky white incisors. However, the expression of Smad3 in Med1 ablation mice and the impact of Med1 on functional integration between Smad3 and Notch1 remains unclear. Cre-loxP-based C57/BL6 mice with epithelial-specific Med1 knockout (Med1 KO) backgrounds were generated. Mandibles and dental epithelial stem cells (DE-SCs) from incisors cervical loop (CL) were isolated from wild-type (CON) mice and Med1 KO mice. Transcriptome sequencing was used to analyze the differences of CL tissue between KO and CON mice. The results revealed the enrichment of TGF-β signaling pathway. qRT-PCR and western blot were performed to show the gene and protein expression of Smad3, pSmad3, Notch1 and NICD, the key regulators of TGF-β and Notch1 signaling pathway. Expression of Notch1 and Smad3 was confirmed to be down-regulated in Med1 KO cells. Using activators of Smad3 and Notch1 on Med1 KO cells, both pSmad3 and NICD were rescued. Moreover, adding inhibitors and activators of Smad3 and Notch1 to cells of CON groups respectively, the protein expressions of Smad3, pSmad3, Notch1 and NICD were synergistically affected. In summary, Med1 participates in the functional integration of Smad3 and Notch1, thus promoting enamel mineralization.

Prolyl isomerase Pin1 promotes extracellular matrix production in hepatic stellate cells through regulating formation of the Smad3-TAZ complex

Hepatic stellate cells (HSCs) produce extracellular matrixes (ECMs), such as collagen and fibronectin, in response to stimulation with transforming growth factor β (TGFβ). The massive ECM accumulation in the liver due to HSCs causes fibrosis which eventually leads to hepatic cirrhosis and hepatoma development. However, details of the mechanisms underlying continuous HSC activation are as yet poorly understood. We thus attempted to elucidate the role of Pin1, one of the prolyl isomerases, in the underlying mechanism(s), using the human HSC line LX-2. Treatment with Pin1 siRNAs markedly alleviated the TGFβ-induced expressions of ECM components such as collagen 1a1/2, smooth muscle actin and fibronectin at both the mRNA and the protein level. Pin1 inhibitors also decreased the expressions of fibrotic markers. In addition, it was revealed that Pin1 associates with Smad2/3/4, and that four Ser/Thr-Pro motifs in the linker domain of Smad3 are essential for binding with Pin1. Pin1 significantly regulated Smad-binding element transcriptional activity without affecting Smad3 phosphorylations or translocation. Importantly, both Yes-associated protein (YAP) and WW domain-containing transcription regulator (TAZ) also participate in ECM induction, and upregulate Smad3 activity rather than TEA domain transcriptional factor transcriptional activity. Although Smad3 interacts with both TAZ and YAP, Pin1 facilitates the Smad3 association with TAZ, but not that with YAP. In conclusion, Pin1 plays pivotal roles in ECM component productions in HSCs through regulation of the interaction between TAZ and Smad3, and Pin1 inhibitors may have the potential to ameliorate fibrotic diseases.

Jiawei Taohe Chengqi Decoction attenuates hepatic fibrosis by preventing activation of HSCs through regulating Src/ERK/Smad3 signal pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Jiawei Taohe Chengqi Decoction (JTCD) is a Traditional Chinese Medicine (TCM) formula modified from Taohe Chengqi Decoction in the classic ancient literature of TCM "Treatise on Febrile Diseases". Clinical and pharmacological studies have shown that JTCD has a therapeutic effect on hepatic encephalopathy, non-alcoholic fatty liver, cirrhotic ascites, and can alleviate acute liver injury in rats. Our previous studies confirmed that JTCD could alleviate hepatic fibrosis and activation of hepatic stellate cells (HSCs). However, its mechanism remains unclear.

AIM OF THE STUDY

This study aimed to elucidate the mechanism of Src Signal on hepatic fibrosis and HSCs activation, and whether JTCD inhibited hepatic fibrosis and HSCs activation through affecting Src Signal.

MATERIALS AND METHODS

In vivo, sixty specific pathogen free male C57/BL6 mice were divided into following six groups: Control group, Model group, SARA group, JTCD low dose group, JTCD medium dose group and JTCD high dose group. Then we established a carbon tetrachloride (CCL₄)-induced hepatic fibrosis mice model, each JTCD group was given the corresponding dose of JTCD by gavage, the SARA group was given Saracatinib and the control group was given saline, once a day for 4 consecutive weeks. UPLC-Q-TOF-MS analyzed chemical components of JTCD. Pathological examination including Hematoxylin and Eosin (H&E), Masson and Sirius red staining was used to observe the characteristic of hepatic fibrosis. Automatic biochemical analyzer detected the levels of alanine aminotransfease (ALT), and aspartate transaminase (AST) in serum. Western-blot and immunohistochemical staining (IHC) detected protein expression. In vitro, we used shRNA to knock down the expression of Src in immortalized human hepatic stellate cell line (LX-2), then intervened with ERK1/2 agonists/inhibitors and JTCD-containing serum after transforming growth factor β1 (TGF-β1) treatment. Immunofluorescence and western-blot detected protein expression. The migratory characteristic of HSCs was assessed by wound-healing assay.

RESULTS

We identified 135 chemical components in the water extract of JTCD, and the water extract of JTCD contains a variety of anti-hepatic fibrosis components. Compared to the model group, hepatic fibrosis performance was significantly improved, the serum levels of ALT and AST were significantly decreased in JTCD groups and SARA group, IHC staining and western blot results indicated that JTCD decreased the expressions of α-smooth muscle actin (α-SMA), phospho-Src (Tyr416), phospho-ERK1/2 and phospho-Smad3. In vitro, JTCD-containing serum could significantly decrease the protein expressions of α-SMA, phospho-Src (Tyr416), phospho-ERK1/2 and phospho-Smad3 according to the results of western-blot and immunofluorescence, in addition, JTCD-containing serum inhibited the mobility and activation of LX-2. What's more, after intervening with Src-shRNA, ERK1/2 agonists/inhibitors and JTCD-containing serum, the western-blot results showed that Src/ERK/Smad3 signal has an important role in hepatic fibrosis and HSCs, and JTCD attenuates hepatic fibrosis by preventing activation of HSCs through regulating Src/ERK/Smad3 signal pathway.

CONCLUSIONS

The results showed that Src kinase promoted hepatic fibrosis and HSCs activation through the ERK/Smad3 signal pathway. More importantly, the mechanism by which JTCD attenuated hepatic fibrosis and HSCs activation was by inhibiting the Src/ERK/Smad3 signal pathway.

Low dose Taxol ameliorated renal fibrosis in mice with diabetic kidney disease by downregulation of HIPK2

Our previous studies reported that low-dose paclitaxel (Taxol) ameliorated renal fibrosis in the unilateral ureteral obstruction and remnant kidney models. However, the regulatory role of Taxol in diabetic kidney disease (DKD) is still unclear. Herein, we observed that low-dose Taxol attenuated high glucose-increased expression of fibronectin, collagen I and collagen IV in Boston University mouse proximal tubule cells. Mechanistically, Taxol suppressed the expression of homeodomain-interacting protein kinase 2 (HIPK2) via disrupting the binding of Smad3 to HIPK2 promoter region, and consequently inhibited the activation of p53. Besides, Taxol ameliorated RF in Streptozotocin mice and db/db-induced DKD via suppression of Smad3/HIPK2 axis as well as inactivation of p53. Altogether, these results suggest that Taxol can block Smad3-HIPK2/p53 axis, thereby attenuating the progression of DKD. Hence, Taxol is a promising therapeutic drug for DKD.

Monocyte-derived immature dendritic cells negatively regulate hepatic stellate cells in vitro by secreting IL-10

The development of liver fibrosis is associated with inflammatory responses resulting from chronic liver disease. Immature dendritic cells (imDCs) play an important role in modulating the inflammatory environment of the liver. This study investigated the effects of imDCs on the regulation of hepatic stellate cells (HSCs) during liver fibrosis. We isolated and induced imDCs from monocytes of healthy volunteers, activated LX-2 cells with TGF-β to establish in vivo liver fibrosis HSCs model, and then set up a cell co-culture system with transwell membranes. imDC surface markers and apoptosis rates of LX-2 cells were detected by flow cytometry. The concentration of IL-10 secreted by imDC was measured through ELISA. The expression of α-SMA in LX-2 after co-culture was examined by qRT‑PCR. Proliferation of LX-2 cells were detected by CCK-8. The western blot was used to illustrate the LX-2 activation-related proteins such as Smad3/7 and TGF-β1. The imDCs co-culture group and the interleukin-10 (IL-10) treatment group had similar results, as they were both able to increase apoptosis, inhibit proliferation, downregulate α-SMA mRNA, and reduce TGF-β1 and Smad3 protein expression in LX-2 cells. Additionally, the Smad7 protein level was increased after treatment with imDC and IL-10. However, the results in the IL-10 antagonist group showed the opposite trend to that of imDCs and IL-10 groups. Thus, these results suggest that imDC secretion of IL-10 negatively regulates activated LX-2 cells, probably via inhibition of the TGF-β1/Smad3 pathway and increased expression of Smad7 protein. This may be a potential therapeutic target for liver fibrosis.

Endoplasmic reticulum stress promotes sepsis-induced muscle atrophy via activation of STAT3 and Smad3

Endoplasmic reticulum (ER) stress is involved in skeletal muscle atrophy in various conditions, but the role of ER stress in sepsis-induced muscle atrophy is not well understood. In this study, we conducted experiments in wild-type (WT) mice and C/EBP homologous protein knockout (CHOP KO) mice to explore the role and mechanism of ER stress in sepsis-induced muscle atrophy. Cecal ligation and puncture (CLP) was used to establish a mouse model of sepsis. In WT mice, the body weight, muscle mass, and cross-sectional area of muscle fibers in CLP group both decreased significantly compared with sham group, which revealed that sepsis-induced dramatic muscle atrophy. Additionally, sepsis activated the ubiquitin-proteasome system (UPS), accompanied by the activation of ER stress. In vitro, inhibition of ER stress suppressed the activity of E3 ubiquitin ligases and alleviated the myotube atrophy. In vivo, CHOP KO also reduced the expression of E3 ubiquitin ligases and UPS-mediated protein degradation, and significantly attenuated sepsis-induced muscle atrophy. Deletion of CHOP also decreased the phosphorylation of signal transducer and activator of transcription 3 (STAT3) and Smad3, and inhibition of STAT3 and Smad3 partly reduced proteolysis caused by ER stress in vitro. These findings confirm that ER stress activates UPS-mediated proteolysis and promotes sepsis-induced muscle atrophy, which is partly achieved by activating STAT3 and Smad3.

Formononetin ameliorates ferroptosis-associated fibrosis in renal tubular epithelial cells and in mice with chronic kidney disease by suppressing the Smad3/ATF3/SLC7A11 signaling

AIMS

Chronic kidney disease (CKD) is characterized by interstitial fibrosis, while limited treatment drugs are available. Ferroptosis is a newly identified process that can trigger tubular atrophy and fibrosis. The aim of this study is to investigate the effects of formononetin (FN), a bioflavonoid, on ferroptosis and renal fibrosis.

MAIN METHODS

In vivo experiments, unilateral ureteral obstruction (UUO)- and folic acid (FA, 250 mg/kg)-induced CKD models were constructed in C57BL/6 mice of 6-8 weeks old, followed by the administration with 40 mg/kg/day FN by gavage. For in vitro experiments, ferroptosis was induced with RSL3 or erastin in primary mouse renal tubular epithelial cells (TECs), followed by the addition of indicated concentrations of FN. Then, the levels of ferroptosis and fibrosis were analyzed. The translocation of Smad3, ATF3, and Nrf2 from the cytoplasm to the nucleus was checked by western blotting. The interaction of Smad3 and ATF3 was detected by Co-immunoprecipitation.

KEY FINDINGS

FN dramatically ameliorated tubular injury along with reduced expression of the profibrotic genes including α-SMA, Col1a1, and fibronectin in both two CKD mouse models and RSL3/erastin-treated TECs. Furthermore, FN administration also significantly suppressed ferroptosis, as evidenced by increased expression of SLC7A11 and GPX4, and decreased levels of 4-HNE. In mechanism, FN disrupted the interaction between Smad3 and ATF3, resulting in the blocking of their translocation from the cytoplasm to the nucleus. In addition, FN also promoted the separation of the Nrf2/Keap1 complex and enhanced Nrf2 nuclear accumulation.

SIGNIFICANCE

FN alleviates CKD by impeding ferroptosis-associated fibrosis by suppressing the Smad3/ATF3/SLC7A11 signaling and could serve as a candidate therapeutic drug for CKD.

P311 knockdown alleviates hyperoxia-induced injury by inactivating the Smad3 signaling pathway in type II alveolar epithelial cells

P311 is associated with alveolar formation and development. However, the role and possible mechanism of P311 in hyperoxia-induced injury in type II alveolar epithelial cells (AEC II) need to be elucidated. In our study, rat AEC II (RLE-6TN) were exposure to normoxia (21% O₂ and 5% CO₂) or hyperoxia (95% O₂ and 5% CO₂) for 24 h, followed by determination of P311 expression. After knockdown of P311 and hyperoxic treatment, cell viability, cell cycle progression, apoptosis and the Smad3 signaling pathway were examined. Rat AEC II were pretreated with SIS3 HCl for 4 h and then subjected to P311 overexpression plasmid transfection and hyperoxic exposure. Then, cell viability, apoptosis and the Smad3 signaling pathway were determined. The results showed that hyperoxic exposure significantly elevated P311 levels in rat AEC II. P311 knockdown increased cell viability, accelerated cell cycle progression and inhibited apoptosis, as well as suppression of the Smad3 signaling pathway in hyperoxia-exposed AEC II. Additionally, we found that P311 overexpression enhanced the effects of hyperoxia. Interestingly, SIS3 HCl incubation blocked the effects of P311 overexpression on rat AEC II function under hyperoxic condition, as evidenced by an increase in cell viability, and suppressions of apoptosis and the Smad3 signaling pathway. These results indicate that P311 knockdown may ameliorate hyperoxia-induced injury by inhibiting the Smad3 signaling pathway in rat AEC II. P311 may be a novel target for the treatment of hyperoxia-induced lung injury and even bronchopulmonary dysplasia (BPD).

Treatment with quercetin inhibits SARS-CoV-2 N protein-induced acute kidney injury by blocking Smad3-dependent G1 cell-cycle arrest

Increasing evidence shows that SARS-CoV-2 can infect kidneys and cause acute kidney injury (AKI) in critically ill COVID-19 patients. However, mechanisms through which COVID-19 induces AKI are largely unknown, and treatment remains ineffective. Here, we report that kidney-specific overexpressing SARS-CoV-2 N gene can cause AKI, including tubular necrosis and elevated levels of serum creatinine and BUN in 8-week-old diabetic db/db mice, which become worse in those with older age (16 weeks) and underlying diabetic kidney disease (DKD). Treatment with quercetin, a purified product from traditional Chinese medicine (TCM) that shows effective treatment of COVID-19 patients, can significantly inhibit SARS-CoV-2 N protein-induced AKI in diabetic mice with or without underlying DKD. Mechanistically, quercetin can block the binding of SARS-CoV-2 N protein to Smad3, thereby inhibiting Smad3 signaling and Smad3-mediated cell death via the p16-dependent G1 cell-cycle arrest mechanism in vivo and in vitro. In conclusion, SARS-CoV-2 N protein is pathogenic and can cause severe AKI in diabetic mice, particularly in those with older age and pre-existing DKD, via the Smad3-dependent G1 cell-cycle arrest mechanism. Importantly, we identify that quercetin may be an effective TCM compound capable of inhibiting COVID-19 AKI by blocking SARS-CoV-2 N-Smad3-mediated cell death pathway.

Ligustilide attenuates airway remodeling in COPD mice by covalently binding to MH2 domain of Smad3 in pulmonary epithelium, disrupting the Smad3-SARA interaction

Airway remodeling is one of the hallmarks of chronic obstructive pulmonary disease (COPD) and is closely related to the dysregulation of epithelial-mesenchymal transition (EMT). Smad3, an important transcriptional regulator responsible for transducing TGF-β1 signals, is a promising target for EMT modulation. We found that ligustilide (Lig), a novel Smad3 covalent inhibitor, effectively inhibited airway remodeling in cigarette smoke (CS) combined with lipopolysaccharide (LPS)-induced COPD mice. Oral administration of an alkynyl-modified Lig probe was used to capture and trace target proteins in mouse lung tissue, revealing Smad3 in airway epithelium as a key target of Lig. Protein mass spectrometry and Smad3 mutation analysis via in-gel imaging indicated that the epoxidized metabolite of Lig covalently binds to the MH2 domain of Smad3 at Cys331/337. This irreversible bonding destroys the interaction of Smad3-SARA, prevents Smad3 phosphorylation activation, and subsequently suppresses the nuclear transfer of p-Smad3, the EMT process, and collagen deposition in TGF-β1-stimulated BEAS-2B cells and COPD mice. These findings provide experimental support that Lig attenuates COPD by repressing airway remodeling which is attributed to its suppression on the activation of EMT process in the airway epithelium via targeting Smad3 and inhibiting the recruitment of the Smad3-SARA heterodimer in the TGF-β1/Smad3 pathway.

sFgl2-Treg Positive Feedback Pathway Protects against Atherosclerosis

Soluble fibrinogen-like protein 2 (sFgl2), a novel effector of regulatory T cells (Tregs), has been demonstrated to have potent immunosuppressive functions. Multiple studies indicate that Tregs could exert important atheroprotective effects, but their numbers gradually decrease during atherogenesis. The receptor of sFgl2 can be expressed on Treg precursor cells, while the role of sFgl2 on Treg differentiation and atherosclerosis progression remains unclear. Firstly, we detected that the sFgl2 was decreased in humans and mice with atherosclerotic diseases and was especially lower in their vulnerable plaques. Then, we used both Adeno-associated virus-sFgl2 (AAV-sFgl2)-injected ApoE^-/- mice, which is systemic overexpression of sFgl2, and sFgl2^TgApoE^-/- bone marrow cells (BMC)-transplanted ApoE^-/- mice, which is almost immune-system-specific overexpression of sFgl2, to explore the role of sFgl2 in atherosclerosis. Our experiment data showed that AAV-sFgl2 and BMT-sFgl2 could reduce atherosclerotic area and enhance plaque stability. Mechanistically, sFgl2 increases the abundance and immunosuppressive function of Tregs, which is partly mediated by binding to FcγRIIB receptors and phosphorylating Smad2/3. Collectively, sFgl2 has an atheroprotective effect that is mainly achieved by forming a positive feedback pathway with Treg. sFgl2 and Treg could synergistically protect against atherosclerosis.

Linc00511 Knockdown Inhibited TGF-β1-Induced Epithelial-Mesenchymal Transition of Bronchial Epithelial Cells by Targeting miR-16-5p/Smad3

BACKGROUND

Airway remodeling in patients with asthma was correlated with induced epithelial-mesenchymal transition (EMT) of bronchial epithelial cells.

OBJECTIVE

This study examined the mechanism of Linc00511 on induced EMT of bronchial epithelial cells after transforming growth factor-β1 (TGF-β1) induction.

METHODS

The human bronchial epithelial cell 16HBE was treated with 10 ng/mL TGF-β1 for 12 h, 24 h, or 48 h to induce EMT. Cell proliferation and migration rate were detected using CCK8 and wound healing assays, respectively. The expression of key markers of EMT (E-cadherin, N-cadherin, Small mothers against decapentaplegic family member 3 [Smad3], and slug) was tested by Western blot.

RESULTS

We found that Linc00511 was time dependently increased in TGF-β-treated 16HBE cells. Silencing Linc00511 reduced 16HBE cell proliferation, migration, and EMT progress. In addition, the dual-luciferase reporter assay showed Linc00511 was a molecular sponge for miR-16-5p. MiR-16-5p decreased the expression of Smad3 by targeting its 3'-untranslated region (3'UTR). After TGF-β1 exposure, miR-16-5p silencing counteracted the decreases of 16HBE cell proliferation, migration, and EMT induced by Linc00511 knockdown. And Smad3 overexpression also reversed the inhibitory effect of Linc00511 knockdown on proliferation, migration, and EMT progression in TGF-β1-induced human bronchial epithelial cells.

CONCLUSION

Linc00511 may be a valuable biomarker for asthma therapy.

Dexamethasone Induces Senescence-Associated Changes in Trabecular Meshwork Cells by Increasing ROS Levels Via the TGFβ/Smad3-NOX4 Axis

Glaucoma is a serious complication of glucocorticoid (GC) therapy arising through elevations in intraocular pressure (IOP). Dexamethasone (DEX) is reported to contribute to elevated IOP through different effects on the trabecular meshwork but whether DEX contributes to glaucoma development through the induction of cellular senescence is still unclear. We explored the actions of DEX on transformed human trabecular meshwork cells (HTMCs) using RNA-seq and conducted bioinformatic analyses to determine the affected pathways. Among the 4,103 differentially expressed genes identified in transformed HTMCs treated with 400 nM DEX (2,036 upregulated and 2,067 downregulated genes, respectively), bioinformatic analyses revealed significant enrichment and potential interplay between the transforming growth factor beta (TGFβ)41; signaling and cellular senescence pathways. DEX treatment induced senescence changes in primary and transformed HTMCs as indicated by increases in SA-β-gal positivity, interleukin (IL)-6 secretion, and senescence-associated heterochromatin foci (SAHF) along with selective accumulation of senescence marker p15 and elevations in reactive oxygen species (ROS) levels. Notably, the DEX-induced senescence changes were rescued by treatment with the TGFβ/Smad3 pathway inhibitor SIS3. Furthermore, we show that DEX increases cellular ROS levels via upregulation of NADPH oxidase 4 (NOX4) through activation of Smad3, and that SIS3 decreases ROS levels by downregulating NOX4. Instructively, inhibiting NOX4 with GLX351322 and scavenging ROS with NAC were both effective in preventing DEX-induced senescence changes. Similarly, we found in the mouse model that DEX-ac upregulated p15 and NOX4 expression in the trabecular meshwork, with cotreatment with GLX351322 alleviating elevations in IOP. We establish that DEX induces senescence changes in HTMCs by increasing ROS levels via the TGFβ/Smad3/NOX4 axis, increasing IOP and contributing to glaucoma development.

Transforming growth factor-β1 promotes early odontoblastic differentiation of dental pulp stem cells via activating AKT, Erk1/2 and p38 MAPK pathways

Background/purpose

TGF-β1 (Transforming growth factor-β1) plays an important role in the regeneration and repair of pulp-dentin complex. However, the biological function of TGF-β1 on odontoblastic differentiation remains unclear, mainly due to the processes of differentiation were controlled by complex signaling pathways. This study aimed to investigate the signaling pathways involved in regulating the early differentiation of dental pulp stem cells (DPSCs) by TGF-β1 and their functional role.

Materials and methods

DPSCs were treated with 1 ng/mL TGF-β1 and Western blotting was conducted to examine the activation of protein kinase B (AKT), small mothers against decapentaplegic 3 (Smad3), p38 mitogen-activated protein kinase (p38 MAPK), c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase 1/2 (Erk1/2). DPSCs were exposed to mineralization medium contained TGF-β1 with/without the specific signaling pathway inhibitors, and early odontogenic differentiation was evaluated by assessing the expression of alkaline phosphatase (ALP), collagen type 1 alpha 1 (COL1A), dentin matrix protein 1 (DMP-1) and runt-related transcription factor 2 (Runx2).

Results

TGF-β1 stimulated AKT, Smad3, p38 MAPK, Erk1/2 and JNK phosphorylation in DPSCs within 120 min. TGF-β1 enhanced ALP activity and elevated levels of COL1A, DMP-1 and Runx2. LY294002, U0126 and SB203580 attenuated the effect of TGF-β1 on DPSCs, however, the SIS3 and SP600125 treated groups had no significant effect.

Conclusion

TGF-β1 promotes the early stage of odontoblastic differentiation in DPSCs by activating AKT, Erk1/2 and p38 MAPK signaling pathways, but not by Smad3 and JNK.

ESP-B4 promotes nasal epithelial cell-derived extracellular vesicles containing miR-146a-5p to modulate Smad3/GATA-3 thus relieving allergic rhinitis: ESP-B4/miR-146a-5p in AR

BACKGROUND

Though generally a mild affliction, allergic rhinitis (AR) is very common and causes considerable discomfort. Ephedra sinica polysaccharide is a candidate cost-effective therapy to relieve AR symptoms.

PURPOSE

We explore the molecular mechanism of pure polysaccharide ESP-B4 action in AR.

METHODS

RPMI2650 cells were treated with lipopolysaccharide to induce an in vitro sensitization model, and extracellular vesicles (EVs) were isolated. A rat model of AR was established using ovalbumin as the allergen and was treated with Ephedra sinica polysaccharide to observe changes in rhinitis symptoms, nasal mucosa histopathology and molecular pathology. ESP-B4-treated sensitized cells were adopted in vitro to verify effect of Ephedra sinica polysaccharide on miR-146a-5p expression in RPMI2650 cell-derived EVs and helper T cell differentiation.

RESULTS

miR-146a-5p inhibited Smad3, impeded the Smad3/GATA-3 interaction, upregulated IFN-γ expression, and promoted CD4⁺T cell Th1 differentiation. Treatment with ESP-B4 relieved AR in rats, and elevated miR-146a-5p in the EVs from the nasal epithelial cells, apparently in relation to effects on helper T cell Th1/Th2 equilibrium.

CONCLUSION

Overall, ESP-B4 can promote miR-146a-5p secretion, affect the Th1/Th2 balance of helper T cells, and relieve AR symptoms through Smad3/GATA-3 interaction, thus presenting a potential strategy for AR treatment.

Screening of key biomarkers in osteoporosis: Evidence from bioinformatic analysis

OBJECTIVE

To analyze the expression characteristics of osteoporosis-related genes by bioinformatics and elucidate the pathogenesis of osteoporosis.

METHODS

The differentially expressed genes (DEGs), microRNA (miRNA), and genes with differentially methylated regions (DMRS) in promoters were identified. The protein-protein interaction (PPI) network was constructed and performed. The Clue Gene Ontology analysis and miRNA-mRNA (messenger RNA) regulatory network were constructed using Cytoscape.

RESULTS

Fifty-nine DEGs, 10 differential miRNAs, and 2083 genes with DMRs were screened out. The Proteasome-Modulator (PSMD) family proteins and estrogen receptor 1 (ESR1) are vital for the PPI analysis of DEGs. The interaction network of the Smad3 protein showed that the degree of connection to ESR1, PSMD11, and transcription factor 4 (TCF4) is very high. Homo sapiens (hsa)-miR-106b-5p was differential and regulated TCF4 through building the miRNA-mRNA regulatory network. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment of DEGs focused on vascular smooth muscle contraction, thyroid hormone signaling pathway, and estrogen signaling pathway. The Gene Ontology (GO) function analysis of genes with DMRs in promoters was primarily concentrated in the cell differentiation, positive regulation of CDP-diacylglycerol-serine O-phosphatidyltransferase activity, and positive regulation of C-palmitoyltransferase activity. The KEGG enrichment of genes with DMRs in promoters largely focused on glycerol phospholipid metabolism, histidine metabolism, Adenosine 5'-monophosphate-activated protein kinase signaling pathway, Hedgehog signaling pathway, and mRNA surveillance pathway.

CONCLUSION

Hsa-miRNA-106b-5p regulates bone formation and the pathogenesis of osteoporosis by controlling TCF4, and methylation modification of TCF4 can also affect the pathogenesis of osteoporosis.

Resveratrol inhibits TGF-β1-induced fibrotic effects in human pterygium fibroblasts

BACKGROUND

Resveratrol is a polyphenolic phytoalexin which has the properties of anti-oxidant, anti-inflammatory and anti-fibrotic effects. The aim of this study was to investigate the anti-fibrotic effects of resveratrol in primary human pterygium fibroblasts (HPFs) and elucidate the underlying mechanisms.

METHOD

Profibrotic activation was induced by transforming growth factor-beta1 (TGF-β1). The expression of profibrotic markers, including type 1 collagen (COL1), α-smooth muscle actin (α-SMA), and fibronectin, were detected by western blot and quantitative real-time-PCR after treatment with various concentrations of resveratrol in HPFs to investigate the anti-fibrotic effects. Relative signaling pathways downstream of TGF-β1 were detected by Western blot to assess the underlying mechanism. Cell viability and apoptosis were assessed using CCK-8 assay and flow cytometry to evaluate proliferation and drug-induced cytotoxicity. Cell migration and contractile phenotype were detected through wound healing assay and collagen gel contraction assay.

RESULTS

The expression of α-SMA, FN and COL1 induced by TGF-β1 were suppressed by treatment with resveratrol in dose-dependent manner. The Smad3, mitogen-activated protein kinase (p38 MAPK) and phosphatidylinositol-3-kinase (PI3K) / protein kinase B (AKT) pathways were activated by TGF-β1, while resveratrol attenuated those pathways. Resveratrol also inhibited cellular proliferation, migration and contractile phenotype, and induced apoptosis in HPFs.

CONCLUSIONS

Resveratrol inhibit TGF-β1-induced myofibroblast activation and extra cellular matrix synthesis in HPFs, at least partly, by regulating the TGF-β/Smad3, p38 MAPK and PI3K/AKT pathways.

Elevated Angiotensin-II Levels Contribute to the Pathogenesis of Open-Angle Glaucoma Via Inducing the Expression of Fibrosis-Related Genes in Trabecular Meshwork Cells Through a ROS/NOX4/SMAD3 Axis

Glaucoma including primary open-angle glaucoma (POAG) results from elevations in intraocular pressure (IOP). An eye-localized renin-angiotensin system (RAS) has been implicated in IOP regulation, although its mechanism of action and contribution to glaucoma is poorly understood. Here, we detected significant increases in the levels of angiotensin II (ANGII) in aqueous humor samples from POAG patients. Moreover, we determined that the concentrations of ANGII were positively correlated with IOP, suggesting a role for elevated ANGII levels in eye pathogenesis. Functional investigations demonstrated that ANGII induces the expression of fibrosis-related genes of transformed and primary human trabecular meshwork cells (HTMCs) through the transcriptional upregulation of key fibrotic genes. Parallel experiments using a murine periocular conjunctival fornix injection model confirmed that ANGII induces the expression of fibrosis-related genes in trabecular meshwork (TM) cells in vivo along with increasing IOP. ANGII was revealed to function through increasing the levels of reactive oxygen species (ROS) via selectively upregulating NOX4, with NOX4 knockdown or inhibition with GLX351322 alleviating fibrotic changes induced by ANGII. We further show that ANGII activates Smad3, with both GLX351322 and an inhibitor of Smad3 (SIS3) decreasing the phosphorylation of Smad3 and dampening the ANGII-induced increases in fibrotic proteins. Moreover, NOX4 and Smad3 inhibitors also partially rescued the elevated IOP levels induced by ANGII. Our collective results therefore highlight ANGII as a biomarker and treatment target in POAG together with establishing a causal relationship between ANGII and up-regulation of the expression of fibrosis-related genes of TM cells via a NOX4/ROS axis in cooperation with TGFβ/Smad3 signaling.

Ubiquitin like protein FAT10 repressed cardiac fibrosis after myocardial ischemic via mediating degradation of Smad3 dependent on FAT10-proteasome system

Cardiac fibrosis after myocardial ischemic (MI) injury is a key factor in heart function deterioration. We recently showed that ubiquitin-like protein human HLA-F adjacent transcript (FAT10) plays a novel role in ischemic cardiovascular diseases, but its function in cardiac fibrosis remains unknown. The present study aims to detail the pathophysiological function of FAT10 in MI injury-induced cardiac fibrosis and its underlying mechanism. In vivo, a systemic FAT10 deficiency mouse (Fat10 ^-/-) model was established which exhibited excessive cardiac fibrosis and deleterious cardiac function after MI when compared to wild-type mice. Cardiac fibrotic-related proteins (α-SMA, collagen I and collagen III) content were increased in MI-Fat10 ^-/- mice. Similarly, cardiac FAT10 restoration in Fat10^-/- mice suppressed fibrosis and improved cardiac function. In vitro, FAT10 overexpression exert a protective effect against the transforming growth β1 (TGF-β1)-induced proliferation, migration and differentiation in cardiac fibroblast (CFs), primary CFs from Fat10^-/- mice and human induced pluripotent stem cell-derived CFs (hiPSC-CFs). Furthermore, immunoprecipitation-mass spectrometry (IP-MS) data demonstrated that FAT10 might mediate Smad3, a critical factor in cardiac fibrosis. Combined with rescue assays both in vivo and vitro, the protective effects of FAT10 against cardiac fibrosis was detected to be dependent on Smad3. In depth, Smad3 as a FAT10 specific substrate, FAT10 specifically bind to the K378 site of Smad3 directly via its C-terminal glycine residues and mediated the degradation of Smad3 through the FAT10-proteasome system instead of ubiquitin. In conclusion, we here show that FAT10 is a novel regulator against cardiac fibrosis after MI by mediating Smad3 degradation through FAT10-mediated proteasome system. Our study confirms the cardioprotective role of FAT10 in the heart, and providing a new prospective insight into the regulation of cardiac fibrosis after MI.

TGF-β1 suppresses the T-cell response in teleost fish by initiating Smad3- and Foxp3-mediated transcriptional networks

Transforming growth factor-β1 (TGF-β1) can suppress the activation, proliferation, and function of many T-cell subsets, protecting organisms from inflammatory and autoimmune disease caused by an overexuberant immune response. However, whether and how TGF-β1 regulates T-cell immunity in early vertebrates remain unknown. Here, using a Nile tilapia (Oreochromis niloticus) model, we investigated suppression of the T-cell response by TGF-β1 in teleost species. Tilapia encodes an evolutionarily conserved TGF-β1, the expression of which in lymphocytes is significantly induced during the immune response following Edwardsiella piscicida infection. Once activated, tilapia T cells increase TGF-β1 production, which in turn suppresses proinflammatory cytokine expression and inhibits T-cell activation. Notably, we found administration of TGF-β1 cripples the proliferation of tilapia T cells, reduces the potential capacity of Th1/2 differentiation, and impairs the cytotoxic function, rendering the fish more vulnerable to bacterial infection. Mechanistically, TGF-β1 initiates the TGF-βR/Smad signaling pathway and triggers the phosphorylation and nuclear translocation of Smad2/3. Smad3 subsequently interacts with several transcriptional partners to repress transcription of cytokines IL-2 and IFN-γ but promote transcription of immune checkpoint regulator CTLA4 and transcription factor Foxp3. Furthermore, TGF-β1/Smad signaling further utilizes Foxp3 to achieve the cascade regulation of these T-cell genes. Taken together, our findings reveal a detailed mechanism by which TGF-β1 suppresses the T cell-based immunity in Nile tilapia and support the notion that TGF-β1 had already been employed to inhibit the T-cell response early in vertebrate evolution, thus providing novel insights into the evolution of the adaptive immune system.