Inhibition Of Smad3 Phosphorylation Research Articles

Lithium inhibits tumor lymphangiogenesis and metastasis through the inhibition of TGFBIp expression in cancer cells.

Metastasis is the main cause of mortality in cancer patients. Although there are many anti-cancer drugs targeting tumor growth, anti-metastatic agents are rarely developed. Angiogenesis and lymphangiogenesis are crucial for cancer progression; in particular, lymphangiogenesis is pivotal for metastasis in cancer. Here we report that lithium inhibits colon cancer metastasis by blocking lymphangiogenesis. Lithium reduces the expression of transforming growth factor-β-induced protein (TGFBIp) in colon cancer cells by inhibiting Smad3 phosphorylation via GSK3β inactivation. Moreover, lithium inhibits lymphatic endothelial cell migration, which is increased upon TGFBIp expression in tumor cells. Lithium had no significant effect on SW620 tumor growth in vitro and in vivo; however, it inhibited lymphangiogenesis in tumors. In tumor xenografts model, lithium was found to prevent metastasis to the lungs, liver, and lymph nodes by inhibiting TGFBIp-induced tumor lymphangiogenesis. Collectively, our findings demonstrate a novel role of lithium in the inhibition of colon cancer metastasis by blocking TGFBIp expression, and thereby TGFBIp-induced lymphangiogenesis, in primary tumors.

Hydroxysafflor Yellow A Attenuates Bleomycin-induced Pulmonary Fibrosis in Mice.

Hydroxysafflor yellow A (HSYA) is an active component of Carthamus tinctorius L., and we want to investigate whether HSYA attenuates pulmonary fibrosis induced by bleomycin (BLM) in mice. The mice received a BLM via oropharyngeal aspiration, and HSYA was intraperitoneally injected. Arterial blood gas analysis was performed. Morphological changes and hydroxyproline content were measured. mRNA expression of transforming growth factor-β1 (TGF-β1), connective tissue growth factor, α-smooth muscle actin (α-SMA), and collagen I was measured by real-time polymerase chain reaction. α-SMA-positive cells in lung tissues were detected by immunohistochemical staining. A549 cell was cultured, and morphological changes were observed after TGF-β1 and HSYA treatment. mRNA expression was detected by real-time polymerase chain reaction. Phosphorylation of Smad3 was evaluated by western blotting. HSYA decreased the lung consolidation area and collagen deposition in mice with pulmonary fibrosis. The blood gas changes due to BLM were attenuated by HSYA. HSYA also alleviated the BLM-induced increase of TGF-β1, connective tissue growth factor, α-SMA, and collagen I mRNA levels. HSYA treatment inhibited the increase of α-SMA expression, Smad3 phosphorylation, the morphological changes in lung tissue. HSYA inhibits Smad3 phosphorylation and elevated expression of collagen I mRNA in epithelial-mesenchymal transition induced by TGF-β1.

Abstract 13694: Hsf1 Attenuates Pressure Overload Induced-cardiac Fibrosis via Inhibiting Smad3 Phosphorylation and Nuclear Translocation

Introduction: Heat shock transcription factor 1 (HSF1) is an intrinsic cardioprotective factor against cardiac hypertrophy. However, little is known about the role of HSF1 in cardiac fibrosis. Here we hypothesize that HSF1 reverses pressure overload induced-cardiac fibrosis via inhibiting Smad3 phosphorylation and nuclear translocation. Methods: Human tissue samples were collected from the left ventricles of dilated cardiomyopathy patients undergoing heart transplant and normal heart donors for control and were interrogated via western blot and realtime-PCR. A HSF1 transgenic (TG) mouse was generated. Transverse aortic constriction (TAC) was performed with wild type (WT) mice as control and cardiac structure and function were measured by echocardiography and pathological test. Cardiomyocytes (CMs) isolated from neonatal mice were imposed with mechanical stretch (MS) in vitro. Results: HSF1 phosphorylation at Ser230 was significantly decreased in failing hearts (55% vs normal hearts) characterized with significant cardiac fibrosis manifested with increased expression of collagen III and connective tissue growth factor (CTGF) . WT mice and TG mice were subjected to TAC. After 4 weeks of TAC, WT mice developed a remarkable maladaptive hypertrophy and cardiac fibrosis in comparison to WT mice. TG mice exhibited a smaller LV end-diastolic diameter (LVEDD), higher ejection fraction (EF), decreased LV weight/tibial length (LW/TL) and CMs cross sectional area (CSA), less interstitial and perivascular fibrosis, as well as preserved expression of collagen III and CTGF compared to WT mice. TG mouse hearts also showed reduced phosphorylation and nuclear translocation of Smad3 than WT mice. MS was found to significantly inhibit HSF1 phosphorylation, but promoted the Smad3 phosphorylation and nuclear translocation in CMs. Co-Immunoprecipitation showed that HSF1 directly binds Smad3 in CMs in vitro, which was decrease by MS or treatment with KNK437 (HSF1 inhibitor). TG mice demonstrate more of HSF1 and Smad3 binding and less phosphorylation and nuclear translocation of Smad3 compared to WT mice after TAC. Conclusion: HSF1 attenuates pressure overload induced-cardiac fibrosis by inhibiting Smad3 phosphorylation and nuclear translocation.

Reversal of stemness in multidrug-resistant hepatocellular carcinoma cells by SIS3

To investigate whether SIS3, a specific inhibitor of Smad3 phosphorylation, can reverse the stemness of multidrug-resistant(MDR) hepatocellular carcinoma cells. MDR HCC Huh7.5.1/ADM cell lines were developed by exposing parental cells to stepwise increasing concentrations of ADM. CCK-8 assay was used to determine the cellular sensitivity of various anticancer drugs. Flow cytometry (FCM) was used to analyze the expression level of cancer stem cell marker CD133. Clone formation assay and mouse subcutaneous xenograft tumors were used to investigate the tumorigenicity in vitro and in vivo. Western blotting (WB) was used to analyze the changes of expressions of CD133, Smad3, Bcl-2, Bax and p-Smad3 in different conditions. ADM treatment of HCC cells in vitro resulted in a development of subline, Huh7.5.1/ADM cells, with CSC phenotypes: stable MDR phenotype (besides ADMc Huh7.5.1/ADM cells were also more resistant to some other anticancer drugs including VCR, MMC and CTX ) (IC50: 0.215 ± 0.018 vs. 0.123 ± 0.004, 0.145 ± 0.009 vs. 0.014 ± 0.002, 1.021 ± 0.119 vs. 0.071 ± 0.006, 27.007 ± 1.606 vs. 1.919 ± 0.032) (unit: µg/ml) (P<0.05). Huh7.5.1/ADM cells enriched the cancer stem-like cell fraction (CD133-positive subpopulation) (76.06 ± 2.948% vs. 25.38 ± 4.349%) (P<0.05), had stronger tumorigenicity in vivo and colony formation ability, and activated the Smad3 activity. Inhibition of Smad3 activity by SIS3 decreased stemness of the Huh7.5.1/ADM cells: CD133-positive subpopulation (48.49 ± 2.304% vs. 76.06 ± 2.948%) (P<0.05); ADM IC50: (0.112 ± 0.019 vs. 0.215 ± 0.018), VCR IC50 (0.065 ± 0.013 vs. 0.145±0.009), MMC IC₅₀ (0.749 ± 0.121 vs. 1.021 ± 0.119), CTX IC50 (10.576 ± 1.248 vs. 27.007 ± 1.606) (unit: µg/ml) (P<0.05), and decreased tumorigenicity and colony formation ability. SIS3 as a specific inhibitor of Smad3 signal is involved in the stemness of multidrug resistant hepatocellular carcinoma cells.

Mitogen-activated protein kinase activator with WD40 repeats (MAWD) and MAWD-binding protein induce cell differentiation in gastric cancer.

BackgroundOur previous proteomic analysis revealed that mitogen-activated protein kinase activator with WD40 repeats (MAWD) and MAWD-binding protein (MAWBP) were downregulated in gastric cancer (GC) tissues. These proteins interacted and formed complexes in GC cells. To investigate the role of MAWD and MAWBP in GC differentiation, we analyzed the relationship between MAWD/MAWBP and clinicopathologic characteristics of GC tissues and examined the expression of E-cadherin and pepsinogen C (PGC)—used as gastric mucosa differentiation markers—in MAWD/MAWBP-overexpressing GC cells and xenografts.MethodsWe measured MAWD, MAWBP, transforming growth factor-beta (TGF-beta), E-cadherin, and PGC expression in 223 GC tissues and matched-adjacent normal tissues using tissue microarray and immunohistochemistry (IHC) analyses, and correlated these expression levels with clinicopathologic features. MAWD and MAWBP were overexpressed alone or together in SGC7901 cells and then E-cadherin, N-cadherin, PGC, Snail, and p-Smad2 levels were determined using western blotting, semiquantitative RT-PCR, and immunofluorescence analysis. Alkaline phosphatase (AKP) activity was measured to investigate the differentiation level of various transfected cells, and the transfected cells were used in tumorigenicity assays and for IHC analysis of protein expression in xenografts.ResultsMAWD/MAWBP positive staining was significantly lower in GC tissues than in normal samples (P < 0.001), and the expression of these proteins was closely correlated with GC differentiation grade. Kaplan–Meier survival curves indicated that low MAWD and MAWBP expression was associated with poor patient survival (P < 0.05). The differentiation-related proteins E-cadherin and PGC were expressed in GC tissues at a lower level than in normal tissues (P < 0.001), but were upregulated in MAWD/MAWBP-overexpressing cells. N-cadherin and Snail expression was strongr in vector-expressing cells and comparatively weaker in MAWD/MAWBP co-overexpressing cells. MAWD/MAWBP co-overexpression inhibited Smad2 phosphorylation and nuclear translocation (P < 0.05), and AKP activity was lowest in MAWD/MAWBP coexpressing cells and highest in vector-expressing cells (P < 0.001). TGF-beta, E-cadherin, and PGC expression in xenograft tumors derived from MAWD/MAWBP coexpressing cells was higher than that in control.ConclusionsMAWD and MAWBP were downregulated and associated with the differentiation grade in GC tissues. MAWD and MAWBP might induce the expression of differentiation-related proteins by modulating TGF-beta signaling in GC cells.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-015-1637-7) contains supplementary material, which is available to authorized users.

Transforming growth factor-β1 induces type II collagen and aggrecan expression via activation of extracellular signal-regulated kinase 1/2 and Smad2/3 signaling pathways.

Transforming growth factor (TGF)‑β regulates the anabolic metabolism of articular cartilage and prevents cartilage degradation. TGF‑β1 influences cellular proliferation, differentiation and the extracellular matrix through activation of the extracellular signal‑regulated kinase (ERK)1/2 and Smad2/3 signaling pathways. However, it has remained to be fully elucidated precisely how the ERK1/2 and Smad2/3 signaling pathways mediate anabolic processes of articular cartilage. The present study investigated how ERK1/2 and Smad2/3 signaling mediate TGF‑β1‑stimulated type II collagen and aggrecan expression in rat chondrocytes. The results confirmed that TGF‑β1 stimulates type II collagen and aggrecan expression in rat chondrocytes, and furthermore, that the ERK1/2 and Smad2/3 signaling pathways were activated by TGF‑β1. Conversely, the TGF‑β receptor I (ALK5) kinase inhibitor SB525334 significantly impaired TGF‑β1‑induced type II collagen and aggrecan expression, coinciding with a reduction of ERK1/2 and Smad3 phosphorylation. In addition, TGF‑β1‑induced type II collagen and aggrecan expression were significantly suppressed by ERK1/2 inhibitor PD98059. Similarly, TGF‑β1‑stimulated type II collagen and aggrecan expression were decreased in the presence of a Smad3 phosphorylation inhibitor SIS3. Therefore, the present study demonstrated that the ERK1/2 and Smad2/3 signaling pathways regulate type II collagen and aggrecan expression in rat chondrocytes.

Overexpression of the FoxO1 Ameliorates Mesangial Cell Dysfunction in Male Diabetic Rats.

The dysfunction of mesangial cells (MCs) in high-glucose (HG) conditions plays pivotal role in inducing glomerular sclerosis by causing the imbalance between generation and degradation of extracellular matrix (ECM) proteins, which ultimately leads to diabetic nephropathy. This study was designed to determine the function of forkhead box protein O1 (FoxO1), an important transcription factors in regulating cell metabolism and oxidative stress, in MCs in HG conditions. Up-regulation of fibronectin, collagen type IV, and plasminogen activator inhibitor (PAI-1) was observed under HG conditions in vivo and in vitro, accompanied with elevation of protein kinase B (Akt) phosphorylation and reduction of FoxO1 bioactivity. After overexpression of constitutively active (CA) FoxO1 in vivo and in vitro by using lentivirus vector, in vivo and in vitro, FoxO1 expression and activity was increased, in accordance with up-regulation of antioxidative genes (catalase and superoxide dismutase, leading to alleviated oxidative stress as well as attenuated Akt activity, whereas overexpression of wild type-FoxO1 only expressed partial effect. Moreover, CA-FoxO1 decreased the expression of fibronectin, collagen type IV, and PAI-1, causing amelioration of renal pathological changes and decrease of ECM protein deposition in glomerulus. Overexpression of CA-FoxO1 in renal cortex also decreased activin type-I receptor-like kinase-5 levels and increased signaling mothers against decapentaplegic (Smad) 7 levels, and simultaneously inhibited Smad3 phosphorylation. Results from in vitro study indicated that increased combination of FoxO1 and Smad3 may interfere with the function of Smad3, including Smad3 phosphorylation and translocation, interaction with cAMP response element binding protein (CREB)-binding protein, and binding with PAI-1 promoter. Together, our findings shed light on the novel function of FoxO1 in inhibiting ECM deposition, which is beneficial to ameliorate MC dysfunction.

Ski prevents TGF-β-induced EMT and cell invasion by repressing SMAD-dependent signaling in non-small cell lung cancer.

Epithelial-mesenchymal transition (EMT) is a key event in cancer metastasis, which confers cancer cells with increased motility and invasiveness, and EMT is characterized by loss of epithelial marker E-cadherin and gain of mesenchymal marker N-cadherin. Transforming growth factor-β (TGF-β) signaling is a crucial inducer of EMT in various types of cancer. Ski is an important negative regulator of TGF-β signaling, which interacts with SMADs to repress TGF-β signaling activity. Although there is accumulating evidence that Ski functions as a promoter or suppressor in human types of cancer, the molecular mechanisms by which Ski affects TGF-β-induced EMT and invasion in non-small cell lung cancer (NSCLC) are not largely elucidated. In the present study, we investigated the mechanistic role of Ski in NSCLC metastasis. Ski was significantly reduced in metastatic NSCLC cells or tissues when compared with non-metastatic NSCLC cells or tissues. Moreover, following TGF-β stimulation Ski-silenced A549 cells had more significant features of EMT and a higher invasive activity when compared with A549 cells overexpressing Ski. Mechanistically, Ski-silenced and overexpressed A549 cells showed an increase and a reduction in the SMAD3 phosphorylation level, respectively. This was supported by plasminogen activator inhibitor-1 (PAI-1) promoter activity obtained in Ski-silenced and overexpressed A549 cells. However, after treatment of SIS3 (inhibitor of SMAD3 phosphorylation) followed by TGF-β1 stimulation, we did not observe any effect of Ski on TGF-β-induced EMT, and invasion in Ski-silenced and overexpressed A549 cells. In conclusion, our findings suggest that Ski represses TGF-β-induced EMT and invasion by inhibiting SMAD-dependent signaling in NSCLC.

Aqueous and alcoholic extracts of Triphala and their active compounds chebulagic acid and chebulinic acid prevented epithelial to mesenchymal transition in retinal pigment epithelial cells, by inhibiting SMAD-3 phosphorylation.

Epithelial to Mesenchymal Transition (EMT) of the retinal pigment epithelium is involved in the pathogenesis of proliferative vitreoretinopathy (PVR) that often leads to retinal detachment. In this study, Triphala, an ayurvedic formulation and two of its active ingredients, namely chebulagic acid and chebulinic acid were evaluated for anti-EMT properties based on in vitro experiments in human retinal pigment epithelial cell line (ARPE-19) under TGFβ1 induced conditions. ARPE-19 cells were treated with TGFβ1 alone or co-treated with various concentrations of aqueous extract (AqE) (30 - 300 μg/ml); alcoholic extract (AlE) (50 - 500 μg/ml) of triphala and the active principles chebulagic acid (CA) and chebulinic acid (CI) (CA,CI: 50 - 200 μM). The expression of EMT markers namely MMP-2, αSMA, vimentin and the tight junction protein ZO-1 were evaluated by qPCR, western blot and immunofluorescence. The functional implications of EMT, namely migration and proliferation of cells were assessed by proliferation assay, scratch assay and transwell migration assay. AqE, AlE, CA and CI reduced the expression and activity of MMP-2 at an ED50 value of 100 μg/ml, 50 μg/ml, 100 μM and 100 μM, respectively. At these concentrations, a significant down-regulation of the expression of αSMA, vimentin and up-regulation of the expression of ZO-1 altered by TGFβ1 were observed. These concentrations also inhibited proliferation and migration of ARPE-19 cells induced by TGFβ1. EMT was found to be induced in ARPE-19 cells, through SMAD-3 phosphorylation and it was inhibited by AqE, AlE, CA and CI. Further studies in experimental animals are required to attribute therapeutic potential of these extracts and their active compounds, as an adjuvant therapy in the disease management of PVR.

(±)-Sinensilactam A, a pair of rare hybrid metabolites with Smad3 phosphorylation inhibition from Ganoderma sinensis.

(+)- and (-)-Sinensilactam A (1), novel hybrid metabolites possessing a unique 2H-pyrrolo[2,1-b][1,3]oxazin-6(7H)-one ring system, were isolated from the fruit bodies of Ganoderma sinensis. The structures of these substances and absolute configurations at their stereocenters were assigned using spectroscopic and computational methods along with X-ray crystallographic analysis. A plausible pathway for the biosynthesis of 1 is proposed. (-)-1 was found to be a Smad3 phosphorylation inhibitor in TGF-β1 induced human renal proximal tubular cells.

GQ5 Hinders Renal Fibrosis in Obstructive Nephropathy by Selectively Inhibiting TGF-β-Induced Smad3 Phosphorylation.

TGF-β1, via Smad-dependent or Smad-independent signaling, has a central role in the pathogenesis of renal fibrosis. This pathway has been recognized as a potential target for antifibrotic therapy. Here, we identified GQ5, a small molecular phenolic compound isolated from the dried resin of Toxicodendron vernicifluum, as a potent and selective inhibitor of TGF-β1-induced Smad3 phosphorylation. In TGF-β1-stimulated renal tubular epithelial cells and interstitial fibroblast cells, GQ5 inhibited the interaction of Smad3 with TGF-β type I receptor (TβRI) by blocking binding of Smad3 to SARA, suppressed subsequent phosphorylation of Smad3, reduced nuclear translocation of Smad2, Smad3, and Smad4, and downregulated the transcription of major fibrotic genes such as α-smooth muscle actin (α-SMA), collagen I, and fibronectin. Notably, intraperitoneal administration of GQ5 in rats immediately after unilateral ureteral obstruction (UUO) selectively inhibited Smad3 phosphorylation in UUO kidneys, suppressed renal expression of α-SMA, collagen I, and fibronectin, and resulted in impressive renal protection after obstructive injury. Late administration of GQ5 also effectively attenuated fibrotic lesions in obstructive nephropathy. In conclusion, our results suggest that GQ5 hinders renal fibrosis in rats by selective inhibition of TGF-β1-induced Smad3 phosphorylation.

ALPHA-11 INTEGRIN EXPRESSION IS ASSOCIATED WITH LEFT VENTRICULAR REMODELING: HUMAN AND CORRELATIVE EXPERIMENTAL STUDIES

Integrins, transmembrane receptors, have two major functions: 1) cell attachment to the extracellular matrix (ECM) and 2) signal transduction from the ECM to the cell. In the heart, various pathological stimuli induce adverse ECM remodeling, including fibrosis and excess collagen deposition, contributing to heart failure (HF) in the vast majority of patients. Accordingly, collagen fibril-binding integrins expressed by cardiac fibroblasts may contribute to HF. Notably, the α11β1 integrin (α11) is mainly expressed by fibroblasts and binds preferentially to type I collagen fibers. Currently, the role of the α11 in pathological remodeling of the heart is not defined. We examined the association of α11 in human end-stage HF and experimentally-induced HF in mice. In human LV sections obtained from patients with end-stage idiopathic (n = 5) and ischemic (n = 5) HF, qRT-PCR and Western Blot analysis showed varied α11 mRNA and protein expression. α11 expression appeared upregulated and downregulated in ischemic and idiopathic HF relative to control (1.2 ± 0.34 vs. 0.83 ± 0.34, mRNA, 1.4 ± 0.28 vs. 0.87 ± 0.37, protein), respectively, suggesting a unique role in human end-stage HF (Figure 1). We examined α11 in experimental HF. Normal C57 mice were divided into two groups: 1) transverse aortic constriction (TAC; n = 13) and 2) sham (n = 14). At 6 weeks, mice underwent echocardiography and invasive pressure-volume (PV) loop analysis, followed by tissue collection. Six weeks post-operation, TAC animals demonstrated significant structural and functional differences, including LV and myocyte hypertrophy and myocardial fibrosis. Hearts from TAC animals demonstrated upregulated α11 mRNA and protein expression, consistent with the human data (Table 1). To determine the mechanism of α11 regulation, we examined isolated human cardiac fibroblasts. Applied tensile force increased α11 expression, which was regulated by TGF-β/Smad signaling. Analysis of the α11 promoter identified a novel Smad binding element at nt-881 and nt-890. Utilizing a specific inhibitor of Smad3 phosphorylation, SIS3, α11 promoter activity induced by tensile force, was reduced, which blocked the increased expression of α11 (all P < 0.05). α11 expression is increased in both human and experimental HF, and the increased expression is mediated in part by Smad3 signaling. These findings suggest that α11 is involved in a positive feedback loop whereby enhanced ECM production increases α11 expression, which in turn drives further matrix accumulation. This suggests that α11 may be a novel target to reduce cardiac fibrosis in the failing heart.View Large Image Figure ViewerDownload (PPT)

Interaction of ERK1/2 and Smad2/3 signaling pathways in TGF-β1-induced TIMP-3 expression in rat chondrocytes

Tissue inhibitor of metalloproteinase-3 (TIMP-3) is an important natural inhibitor of matrix metalloproteinases (MMPs) and of a disintegrin and metalloproteinase with thrombospondin motif (ADAMTs), which can cleave cartilage extracellular matrix components to cause cartilage degradation. In this study, our data suggest TGF-β1 induces TIMP-3 expression through activations of both the ERK1/2 and Smad2/3 signaling pathways. TGF-β1-stimulated TIMP-3 expression was significantly inhibited by SB525334 (TGF-β receptor I kinase inhibitor), accompanied by a reduction in ERK1/2 and Smad3 phosphorylation. We used PD98059 (MEK inhibitor) and SIS3 (inhibitor of Smad3 phosphorylation) to investigate the respective roles of ERK1/2 and Smad2/3 signaling pathways in TGF-β1-induced TIMP-3 expression. The results show PD98059 treatment significantly suppressed TGF-β1-induced ERK1/2 phosphorylation and TIMP-3 expression. Under these conditions, the degree of Smad3 phosphorylation correlated with ERK1/2 activation, which suggests that ERK1/2 may activate Smad3 phosphorylation. SIS3 significantly inhibited TGF-β1-induced Smad3 phosphorylation and TIMP-3 expression. ERK1/2 phosphorylation alone had no effect on TGF-β1-induced TIMP-3 expression, which suggests ERK1/2 via Smad3 phosphorylation regulates TGF-β1-induced TIMP-3 expression. Here, we demonstrate that ERK1/2 may be capable of activating the Smad2/3 signaling pathway to result in TGF-β1-induced TIMP-3 up-regulation.

Ursodeoxycholyl lysophosphatidylethanolamide attenuates hepatofibrogenesis by impairment of TGF-β1/Smad2/3 signalling.

Chronic hepatic inflammation results in liver fibrosis. As effective anti-fibrogenic agents are lacking, we investigated ursodeoxycholyl lysophosphatidylethanolamide (UDCA-LPE), a synthetic bile acid-phospholipid conjugate with anti-inflammatory and anti-apoptotic properties for tis effects on hepatic fibrogenesis. To stimulate fibrogenesis, LX2 hepatic stellate cells were cultured with conditioned medium from CL48 liver cells after exposure to stress-inducing conditions - methionine-choline-deficient (MCD) medium or TNFα/cycloheximide (CHX) - with or without UDCA-LPE preincubation. Anti-fibrogenic effects of UDCA-LPE were further studied in CL48 and LX2 cells and in primary human hepatic stellate cells (HHStec) directly exposed to TGF-β1. To test UDCA-LPE in vivo, C57BL/6 mice were fed a MCD diet for 11 weeks followed by 30 mg·kg(-1) UDCA-LPE 3× per week for 2.5 weeks. Expression of α-smooth muscle actin (α-SMA), α1-collagen, vimentin and TGF-β1 was down-regulated by up to 93% by UDCA-LPE in LX-2 cells cultured with conditioned medium. Also, UDCA-LPE inhibited Smad3 phosphorylation in CL48 cells incubated with MCD medium or TNFα/CHX and in LX2 cells exposed to conditioned medium. UDCA-LPE also decreased phosphorylated Smad3 and Smad2 directly induced by TGF-β1. Inhibition of TGF-β1/Smad2/3 signalling with down-regulation of target genes was confirmed in HHStec. In vivo, UDCA-LPE decreased hepatic α-SMA, α1-collagen and TGF-β1 expression and markedly lowered α-SMA protein and collagen deposition in MCD mice. By blocking TGF-β1/Smad2/3 signalling, UDCA-LPE suppressed key mediators of hepatic fibrogenesis. Thus, UDCA-LPE could be suitable for prevention of fibrotic progression of chronic liver disease.

TGF-β1-elevated TRPM7 channel regulates collagen expression in hepatic stellate cells via TGF-β1/Smad pathway

Transdifferentiation of hepatic stellate cells (HSCs) into myofibroblasts plays a critical role in the development of liver fibrosis, since myofibroblasts are the key cells responsible for excessive deposition of ECM proteins. Transient receptor potential melastatin 7 (TRPM7), a non-selective cation channel with protein serine/threonine kinase activity, has been demonstrated to function in the proliferation of activated HSCs. Here, we investigated the functional role of TRPM7 in collagen deposition in activated HSC-T6 cells (a rat hepatic stellate cell line). TRPM7 mRNA and protein were measured by Real-time PCR and Western blot in TGF-β1-activated HSC-T6 cells in vitro. Results demonstrated that TRPM7 protein was dramatically increased in fibrotic human livers. Stimulation of HSC-T6 cells with TGF-β1 increased TRPM7 mRNA and protein level in a time-dependent manner. Nevertheless, TGF-β1-elicited upregulation of TRPM7 in HSC-T6 cells was abrogated by SB431542 (TGF-β1 receptor blocker) or SIS3 (inhibitor of Smad3 phosphorylation). Additionally, blockade of TRPM7 channels with non-specific TRPM7 blocker 2-APB or synthetic siRNA targeting TRPM7 attenuated TGF-β1-induced expression of myofibroblast markers, as measured by the induction of α-SMA and Col1α1. Silencing TRPM7 also increased the ratio of MMPs/TIMPs by increasing MMP-13 expression and decreasing TIMP-1 and TIMP-2 levels. Strikingly, phosphorylation of p-Smad2 and p-Smad3, associated with collagen production, was decreased in TRPM7 deficient HSC-T6 cells. These observations suggested that TGF-β1 elevates TRPM7 expression in HSCs via Smad3-dependant mechanisms, which in turn contributes Smad protein phosphorylation, and subsequently increases fibrous collagen expression. Therefore, TRPM7 may constitute a useful target for the treatment of liver fibrosis.

Inhibition of intimal hyperplasia in murine aortic allografts by the oral administration of the transforming growth factor-beta receptor I kinase inhibitor SD-208

Transforming growth factor-beta (TGF-β) plays a significant role in the pathogenesis of the intimal hyperplasia of transplant arteriosclerosis (TA). The aim of this study was to evaluate the efficacy of an oral inhibitor of TGF-β receptor I kinase (SD-208) on the development of TA. BALB/c (H-2(d)) donor aortas were transplanted into C57BL/6 (H-2(b)) recipients, and the mice then received different doses (40 or 60 mg/kg) of SD-208 or control vehicle by daily gavage for 8 weeks. The grafts were analyzed by histology and morphometry at 1, 2, 4, 6 and 8 weeks after transplantation. The effects of TGF-β and SD-208 on neointimal smooth muscle-like cell (SMLC) and vascular smooth muscle cell (VSMC) proliferation and migration were evaluated, and the expression levels of Smad3, P-Smad3, connective tissue growth factor (CTGF) and collagen I were determined by in vitro experiments. The intimal hyperplasia of the SD-208-treated group was significantly reduced compared with the vehicle-treated control group (32% and 48% reduction for 40 mg/kg and 60 mg/kg SD-208 compared with the controls, respectively [n = 5], p < 0.05). SD-208 reduced SMLC proliferation and the production of intimal collagen by 21% and 75%, respectively, in the grafts. SD-208 also abolished the promoting effect of TGF-β on SMLC proliferation and migration but did not affect TGF-β inhibition of VSMCs in vitro. CTGF, a protein downstream of TGF-β, was downregulated with the inhibition of Smad3 phosphorylation by SD-208, both in vitro and in vivo. Moreover, we found that the endogenous Smad3 in SMLCs was upregulated from 2 weeks after transplantation and was 64% higher than in VSMCs at 8 weeks. These results demonstrate that SD-208 can effectively reduce the formation of intimal hyperplasia of TA in the murine aortic allograft model.

Ellagic Acid Exerts Anti-proliferation Effects via Modulation of Tgf-Β/Smad3 Signaling in MCF-7 Breast Cancer Cells

Ellagic acid has been shown to inhibit tumor cell growth. However, the underlying molecular mechanisms remain elusive. In this study, our aim was to investigate whether ellagic acid inhibits the proliferation of MCF- 7 human breast cancer cells via regulation of the TGF-β/Smad3 signaling pathway. MCF-7 breast cancer cells were transfected with pEGFP-C3 or pEGFP-C3/Smad3 plasmids, and treated with ellagic acid alone or in combination with SIS3, a specific inhibitor of Smad3 phosphorylation. Cell proliferation was assessed by MTT assay and the cell cycle was detected by flow cytometry. Moreover, gene expression was detected by RT-PCR, real-time PCR and Western blot analysis. The MTT assay showed that SIS3 attenuated the inhibitory activity of ellagic acid on the proliferation of MCF-7 cells. Flow cytometry revealed that ellagic acid induced G0/G1 cell cycle arrest which was mitigated by SIS3. Moreover, SIS3 reversed the effects of ellagic acid on the expression of downstream targets of the TGF-β/Smad3 pathway. In conclusion, ellagic acid leads to decreased phosphorylation of RB proteins mainly through modulation of the TGF-β/Smad3 pathway, and thereby inhibits the proliferation of MCF-7 breast cancer cells.

(±)-Aspongamide A, an N-Acetyldopamine Trimer Isolated from the Insect Aspongopus chinensis, Is an Inhibitor of p-Smad3

(±)-Aspongamide A (1), an unusual trimer of N-acetyldopamine (NADA) bearing a novel tetrahydrobenzo[a]dibenzo[b,e][1,4]dioxine structure, and a pair of NADA dimeric enantiomers (2) were isolated from Aspongopus chinensis. The structures of compounds 1 and 2 were assigned using spectroscopic methods. Compound 1 was found to be an inhibitor of Smad3 phosphorylation in transforming growth factor-β1 (TGF-β1) induced rat renal proximal tubular cells and suppressed extracellular matrix expression in mesangial cells under diabetic conditions.

Inhibitory effects of pitavastatin on fibrogenic mediator production by human lung fibroblasts

AimsIdiopathic pulmonary fibrosis continues to be a devastating clinical disorder for which there are few therapeutic options, and the pathogenesis of this disease remains largely unknown. Statins are inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A reductase in cholesterol biosynthesis, and they have been reported to exert pleiotropic effects on the cellular signaling involved in tissue inflammation and in organ fibrosis/remodeling. We examined the preventive effects of statins on fibrogenic mediator expression and production in normal human lung fibroblasts (NHLF). Main methodsNHLF were pretreated with 100nM pitavastatin or medium alone (control), and were then stimulated with transforming growth factor-β1 (TGF-β1). mRNA expression and protein secretion of several mediators from cells were analyzed by real-time polymerase chain reaction, enzyme-linked immunosorbent assay or multiplex assay. Key findingsTGF-β1-induced expression or production of mediators, such as collagen-1, vascular endothelial growth factor and chemokine C–X–C motif ligand 8, in NHLF pretreated with pitavastatin was significantly suppressed with inhibition of Smad-3 phosphorylation, as compared to untreated controls. In addition, the inhibitory effects of pitavastatin were negated by addition of mevalonate. SignificancePitavastatin appeared to inhibit TGF-β1-induced fibrogenic mediator production from lung fibroblasts via the mevalonic cascade. Although further evaluation of the signaling pathways for these phenomena is necessary, our results suggest the potential benefits of pitavastatin.

The aqueous extract of Lycopus lucidus Turcz ameliorates streptozotocin-induced diabetic renal damage via inhibiting TGF-β1 signaling pathway

Purpose Renal fibrosis characterized by accumulation of extracellular matrix protein results in chronic renal diseases including diabetic nephropathy. Transforming growth factor β1 (TGF-β1) signaling pathway plays a key role in mediating renal fibrosis. Hence, agents that antagonize TGF-β signaling could be candidate for kidney disease therapy. Methods We established renal fibrosis model both in vitro with fibroblast cells treated with rhTGF-β1 and streptozocin(STZ)-induced diabetic nephropathy rats model in vivo and evaluated the effect of the aqueous extract of Lycopus lucidus Turcz, the blood-circulation-promoting Chinese herb, on diabetic nephropathy and investigated the mechanism of action. Results We found that Lycopus suppressed rhTGF-β1-induced Smad2 and ERK1/2 activation, down-regulated the expression of TGF-βRI, TGF-βRII, Smad4 and Smad7 in SV40 MES13 cells without inhibiting cell viability. In vivo, lycopus inhibited Smad2 phosphorylation, reduced mRNA level of TGF-β1, ameliorated expansion of the mesangial area in glomerular tissue and reduced the levels of Scr and BUN of serum and total-SOD (superoxide dismutase) activity in STZ-induced diabetic rats. Conclusion Lycopus is a novel inhibitor of renal fibrosis by blocking TGF-β signaling pathway and possess a protective effect on renal damage of STZ-induced diabetic nephropathy in rats.