Human ucMSCs seeded in a decellularized kidney scaffold attenuate renal fibrosis by reducing epithelial-mesenchymal transition via the TGF-ß/Smad signaling pathway.

BACKGROUND: Renal fibrosis occurs largely through epithelial-mesenchymal transition (EMT). This study explored the beneficial effects of a human umbilical cord mesenchymal stem cell-loaded decellularized kidney scaffold (ucMSC-DKS) on renal fibrosis in a rodent model of post-transplantation renal failure, and the underlying mechanism. METHODS: Rat-derived DKSs were examined after preparation, and then recellularized with human ucMSCs to prepare cell-loaded patches. A rat model of renal failure was established after subtotal nephrectomy (STN). The cell patches were transplanted to remnant kidneys. Changes in renal function, histology, EMT, and proteins related to the transforming growth factor-ß (TGF-ß)/Smad signaling pathway in the remnant kidneys were examined 8 weeks after surgery, compared with non-cell patch controls. RESULTS: The DKSs were acellular and porous, with rich cytokine and major extracellular matrix components. The ucMSCs were distributed uniformly in the DKSs. Renal function was improved, renal fibrosis and EMT were reduced, and the TGF-ß/Smad signaling pathway was inhibited compared with controls at 8 weeks after ucMSC-DKS patch transplantation. CONCLUSIONS: The ucMSC-DKS restores renal function and reduces fibrosis by reducing EMT via the TGF-ß/Smad signaling pathway in rats that have undergone STN. It provides an alternative for renal fibrosis treatment.

Downregulation of miR-21 promotes tibial fracture healing in rabbits through activating ERK pathway.

OBJECTIVE: The aim of this study was to investigate the effect of micro ribonucleic acid (miR)-21 on tibial fracture healing in rabbits by regulating the extracellular signal-regulated kinase (ERK) signaling pathway, and to explore its possible underlying mechanism. MATERIALS AND METHODS: A total of 15 healthy male rabbits were randomly divided into three groups, including: model group A (fracture group, n=5), model group B (fracture treatment group, n=5), and model group C (miR-21 siRNA + treatment group, n=5). Fracture healing was observed by imaging. The content of the serum collagen I and collagen II in rabbits was detected via enzyme-linked immunosorbent assay (ELISA). The morphology of bone tissues was observed via staining. Moreover, the expressions of ERK, transforming growth factor-ß1 (TGF-ß1), and Smad in osteoblasts of tibia were observed via Western blotting and Reverse Transcription-Polymerase Chain Reaction (RT-PCR), respectively. RESULTS: There was bony callus formation in group B and C when compared with group A. Compared with group B, bony callus formation was significantly accelerated in group C, while healing cycle was shortened. Hematoxylin-eosin (HE) staining and Masson staining indicated that compared with group A, group C had more fibrous calluses, new capillaries, and fibroblasts in tissues. Meanwhile, group C exerted better maturity of collagen tissues and higher osteoid content at 20 d after modeling. Compared with group C, there were more osteoid tissues with poor maturity in group B. Meanwhile, intramembranous bone formation was deformed, and collagen content was remarkably lower in group B. The content of serum collagen I and collagen II remarkably increased in group B compared with group A (p<0.05). However, it was significantly upregulated in group C compared with group B, showing statistically significant differences (p<0.05). According to the results of Western blotting, the protein expressions of TGF-ß1, Smad, and ERK in osteoblasts were significantly upregulated in group B when compared with those in group A (p<0.05). However, they increased remarkably in group C when compared with group B (p<0.05). Besides, RT-PCR results revealed that the messenger RNA (mRNA) expressions of TGF-ß1, Smad, and ERK in osteoblasts were significantly higher in group B than those in group A (p<0.05). However, they were markedly raised in group C in comparison with group B (p<0.05). CONCLUSIONS: Down-regulation of miR-21 promotes tibial fracture healing in rabbits by activating the ERK signaling pathway.

The BMP-SMAD pathway mediates the impaired hepatic iron metabolism associated with the ERFE-A260S variant.

The erythroferrone (ERFE) is the erythroid regulator of hepatic iron metabolism by suppressing the expression of hepcidin. Congenital dyserythropoietic anemia type II (CDAII) is an inherited hyporegenerative anemia due to biallelic mutations in the SEC23B gene. Patients with CDAII exhibit marked clinical variability, even among individuals sharing the same pathogenic variants. The ERFE expression in CDAII is increased and related to abnormal erythropoiesis. We identified a recurrent low-frequency variant, A260S, in the ERFE gene in 12.5% of CDAII patients with a severe phenotype. We demonstrated that the ERFE-A260S variant leads to increased levels of ERFE, with subsequently marked impairment of iron regulation pathways at the hepatic level. Functional characterization of ERFE-A260S in the hepatic cell system demonstrated its modifier role in iron overload by impairing the BMP/SMAD pathway. We herein described for the first time an ERFE polymorphism as a genetic modifier variant. This was with a mild effect on disease expression, under a multifactorial-like model, in a condition of iron-loading anemia due to ineffective erythropoiesis.

Glial cell line-derived neurotrophic factor (GDNF) mediates hepatic stellate cell activation via ALK5/Smad signalling.

OBJECTIVE: Although glial cell line-derived neurotrophic factor (GDNF) is a member of the transforming growth factor-ß superfamily, its function in liver fibrosis has rarely been studied. Here, we investigated the role of GDNF in hepatic stellate cell (HSC) activation and liver fibrosis in humans and mice. DESIGN: GDNF expression was examined in liver biopsies and sera from patients with liver fibrosis. The functional role of GDNF in liver fibrosis was examined in mice with adenoviral delivery of the GDNF gene, GDNF sgRNA CRISPR/Cas9 and the administration of GDNF-blocking antibodies. GDNF was examined on HSC activation using human and mouse primary HSCs. The binding of activin receptor-like kinase 5 (ALK5) to GDNF was determined using surface plasmon resonance (SPR), molecular docking, mutagenesis and co-immunoprecipitation. RESULTS: GDNF mRNA and protein levels are significantly upregulated in patients with stage F4 fibrosis. Serum GDNF content correlates positively with α-smooth muscle actin (α-SMA) and Col1A1 mRNA in human fibrotic livers. Mice with overexpressed GDNF display aggravated liver fibrosis, while mice with silenced GDNF expression or signalling inhibition by GDNF-blocking antibodies have reduced fibrosis and HSC activation. GDNF is confined mainly to HSCs and contributes to HSC activation through ALK5 at His39 and Asp76 and through downstream signalling via Smad2/3, but not through GDNF family receptor alpha-1 (GFRα1). GDNF, ALK5 and α-SMA colocalise in human and mouse HSCs, as demonstrated by confocal microscopy. CONCLUSIONS: GDNF promotes HSC activation and liver fibrosis through ALK5/Smad signalling. Inhibition of GDNF could be a novel therapeutic strategy to combat liver fibrosis.

SUMO protease SENP1 acts as a ceRNA for TGFBR2 and thus activates TGFBR2/Smad signaling responsible for LPS-induced sepsis.

This study aims to explore the roles and related mechanisms of SUMO protease SENP1 in sepsis. Here, RNA-sequencing assay showed that SENP1 was significantly increased in human umbilical vein endothelial cells (HUVECs) with LPS treatment. Gene set enrichment analysis (GSEA) of RNA-sequencing dataset revealed that a positive enrichment of inflammation signatures was observed in HUVECs with SENP1 3'UTR overexpression. Further functional annotation analysis revealed that SENP1 3'UTR overexpression was positively correlated with TGFBR2 signaling pathway. Mechanistically, TGFBR2 was identified as a ceRNA (competing endogenous RNA) target of SENP1 and the downstream effectors Smad2/3 were also overexpressed in HUVECs with SENP1 3'UTR overexpression. Injection of SENP1 siRNA following LPS treatment attenuated LPS-induced sepsis, evidenced by the downregulation of IL-2 and TNF-α secretion and prolonged the overall survival of septic mice. Consistent results were obtained in vitro. Additionally, TGFBR2 overexpression partially abrogated SENP1 siRNA-mediated inhibition on LPS-induced sepsis. Thus, these results suggest that SENP1 promotes sepsis via activating the TGFBR2 signaling.

BMP-7/Smad expression in dedifferentiated Schwann cells during axonal regeneration and upregulation of endogenous BMP-7 following administration of PTH (1-34).

PURPOSE:: To determine the expression and distribution of bone morphogenetic protein (BMP)-7 and related molecules during peripheral nerve regeneration and to assess whether administration of parathyroid hormone (PTH) drug (1-34) potentiates the intrinsic upregulation of BMP-7/Smad signaling. METHODS:: The rat sciatic nerves were crushed with an aneurysm clip resulting in axonal degeneration. In the normal nerve, and at 1, 2, 4, and 8 weeks after injury, BMP-7, BMP receptors, p-Smad 1/5/8, and Noggin, the endogenous BMP antagonist, were evaluated. Additionally, the distribution of BMP-7 was assessed by fluorescent double immunostaining. In vitro studies were also performed to examine the effect of BMP-7 and PTH (1-34) administration on rat Schwann cells (SCs). RESULTS:: Aneurysm clip made reliable animal model of the nerve injury with recovery at 8 weeks after the injury. BMP-7/Smad protein and mRNA were significantly upregulated on axon-SCs units at 1 week after injury, and this upregulated expression was maintained for 4 weeks. Besides, significant upregulation of Noggin's expression was observed on axon-SCs units at 2 weeks after injury. Moreover, fluorescent double immunostaining showed co-localization between expression of BMP-7 and p75NTR during axonal regeneration. In the in vitro study, administration of BMP-7 induced significant proliferation of SCs. Application of PTH (1-34) upregulated BMP-7 on SCs. DISCUSSION/CONCLUSION:: BMPs were reported to be involved in protection and recovery after injury as well as in neurogenesis. Our current study showed that BMP/Smad signaling molecules were upregulated on dedifferentiated SCs after peripheral nerve injury and that administration of BMP-7 increased SC viability in vitro. These results suggested that axonal regeneration could be induced via upregulation of endogenous BMP-7 on SCs by PTH (1-34) administration.

Genetic polymorphisms in bone morphogenetic protein receptor type IA gene predisposes individuals to ossification of the posterior longitudinal ligament of the cervical spine via the smad signaling pathway.

BACKGROUND: The present study investigated the molecular mechanisms underlying the 4A > C and -349C > T single nucleotide polymorphisms (SNPs) in bone morphogenetic protein receptor type IA (BMPR-IA) gene, which significantly associated with the occurrence and the extent of ossification of the posterior longitudinal ligament (OPLL) in the cervical spine. METHODS: The SNPs in BMPR-IA gene were genotyped, and the association with the occurrence and severity of OPLL were evaluated in 356 OPLL patients and 617 non-OPLL controls. In stably transfected mouse embryonic mesenchymal stem cells (C3H10T1/2), the expression levels of the BMPR-IA gene and Smad4 protein as well as phosphorylated Smad1/5/8 were detected by Western blotting. In addition, the alkaline phosphatase (ALP) and osteocalcin (OC) activity of osteogenesis specificity protein was assessed using the ALP quantitation and osteocalcin radioimmunoassay kit, respectively. RESULTS: The 4A > C and the -349C > T polymorphisms of BMPR-IA gene were significantly associated with the development of OPLL in the cervical spine. The C allele type in 4A > C polymorphism significantly increases the occurrence and the extent of OPLL. The T allele type in -349C > T polymorphism significantly increases the susceptibility to OPLL, but not the extent of OPLL. The current results further validate our previous observations. The expression levels of BMPR-IA gene were significantly increased in pcDNA3.1/BMPR-IA (mutation type, MT -349C > T; MT 4A > C; MT -349C > T and 4A > C) vector-transfected C3H10T1/2 cells compared to the wild type (WT) vector-transfected cells. The levels of phosphorylated Smad1/5/8 and ALP activity were significantly increased in pcDNA3.1/BMPR-IA (MT -349C > T) vector-transfected C3H10T1/2 cells compared to the WT vector-transfected cells. However, no significant differences were observed in the protein levels of phosphorylated Smad1/5/8 and the ALP activity between MT A/C and WT vector-transfected cells. In addition, no significant differences were observed in the Smad4 protein levels among the experimental groups, as well as in the OC activity between WT vector-transfected and MT C/T, MT A/C, MT C/T and MT A/C vector-transfected cells. CONCLUSIONS: Our results suggest that Smad signaling pathway may play important roles in the pathological process of OPLL induced by SNPs in BMPR-IA gene. These results will help to clarify the molecular mechanisms underlying the SNP and gene susceptibility to OPLL.

Distribution of Smad mRNA and proteins in the rat brain.

Smad proteins are known to transduce the action of TGF-ß superfamily proteins including TGF-ßs, activins, and bone morphogenetic proteins (BMPs). In this study, we examined the expression of Smad1, -2, -3, -4, -5, and -8 mRNA in the rat brain by means of RT-PCR and in situ hybridization (ISH). In addition, we examined the nuclear accumulation of Smad1, -2, -3, -5, and -8 proteins after intracerebroventricular injection of TGF-ß1, activin A, or BMP6 with immunohistochemistry to investigate whether TGF-ß, activin, and/or BMP activate Smads in the rat brain. RT-PCR analysis revealed that Smad1, -2, -3, -4, -5, and -8 mRNA was expressed in the brain and that the Smad3 and Smad8 mRNA differed in the expression level between brain regions. For example, there were high levels of expression of Smad3 mRNA in the cerebral cortex, caudate putamen/globus pallidus, and cerebellum, but low levels in the thalamus and midbrain. Expression of Smad8 mRNA was higher in the midbrain, cerebellum, and pons/medulla oblongata in comparison to the olfactory bulb, cerebral cortex, caudate putamen/globus pallidus, hippocampus/dentate gyrus, and thalamus. ISH signals for Smad1 mRNA were widely detected in the brain except for a small number of regions including the olfactory tubercle, posterior region of hypothalamus, and cerebellar nuclei. ISH signals for Smad2 mRNA were abundantly observed in several brain regions including the olfactory bulb, piriform cortex, basal ganglia, cingulate cortex, epithalamus, including the pineal gland and medial habenular nuclei, hypothalamus, inferior colliculi of the midbrain, and some nuclei in the pons, cerebellar cortex, and choroid plexus. ISH signals for Smad3 mRNA were also abundantly observed in several brain regions. Especially strong signals for Smad3 mRNA were observed in the olfactory tubercle, piriform cortex, basal ganglia, dentate gyrus, and cingulate cortex. ISH signals for Smad5 and Smad8 mRNA were restricted to a small number of brain regions, the signal intensity of which was weak. ISH signals for Smad4 mRNA were detected in all regions examined. Intracerebroventricular injection of activin A induced nuclear accumulation of Smad2 and Smad3 immunoreactivity in neurons. In contrast, intracerebroventricular injection of TGF-ß1 or BMP6 did not induce nuclear accumulation of the immunoreactivity for any Smad in neurons. These results suggest that activin-Smad signaling plays an important role in brain homeostasis.

MiR-181a promotes epithelial to mesenchymal transition of prostate cancer cells by targeting TGIF2.

OBJECTIVE: Prostate cancer is the most commonly diagnosed cancer, and metastatic prostate cancer often leads to poor outcomes for patients. During the metastasis processes, cancer cells acquire a migratory and invasive phenotype. Epithelial to mesenchymal transition (EMT) has been implicated in multiple processes of prostate cancer development including migration, chemoresistance, and carcinogenesis. PATIENTS AND METHODS: Expressions of miR-181a in prostate tumor samples and cancer cells were measured by qRT-PCR. Epithelial or mesenchymal markers were detected by Western blot. Nuclear translocation of Smad 2/3 was measured by immunostaining of prostate cancer cells. RESULTS: In this study, we report an oncogenic role of microRNA-181a in prostate cancer cells and patients. MiR-181a is upregulated in metastatic prostate tumor samples compared with primary prostate tumors. Interestingly, we found that overexpression of miR-181a promotes prostate cancer cell migration and invasion. Moreover, we observed that overexpression of miR-181a contributes to an epithelial to mesenchymal transition phenotype in prostate cancer cells: the epithelial marker, E-cadherin was downregulated, and mesenchymal markers, N-cadherin, vimentin, and snail were upregulated. Consistently, the phosphorylation of Smad 2/3 and the nuclear localization of Smad 2/3 were increased by miR-181a expression. We identified that TGIF2 - a repressor of the Smad pathway - is a direct target of miR-181a in prostate cancer cells. Importantly, restoration of TGIF2 in miR-181a overexpressing prostate cancer cells inhibited the Smad pathway and EMT processes. CONCLUSIONS: This research identifies a molecular mechanism for microRNA-mediated cancer metastasis and improvement novel therapeutic avenue for metastatic prostate cancer patient treatments.

Identification of Tisp40 as an Essential Regulator of Renal Tubulointerstitial Fibrosis via TGF-ß/Smads Pathway.

BACKGROUND: Tisp40, a transcription factor of the CREB/CREM family, is involved in cell proliferation, differentiation and other biological functions, but its role in renal tubulointerstitial fibrosis is unknown. METHODS: In our study, we investigated the effects of Tisp40 on extracellular matrix (ECM) accumulation, epithelial-mesenchymal transition (EMT) and the underlying molecular mechanisms in transforming growth factor-ß (TGF-ß)-stimulated TCMK-1 cells by quantitative real-time polymerase chain reaction (qPCR), Western blot analysis and immunofluorescence in vitro, and further explored the role of Tisp40 on renal fibrosis induced by ischemia-reperfusion (I/R) by qPCR, Western blot analysis, hydroxyproline analysis, Masson trichrome staining and immunohistochemistry staining in vivo. RESULTS: The data showed that Tisp40 was upregulated in a model of renal fibrosis induced by I/R injury (IRI). Upon IRI, Tisp40-deficient mice showed attenuated renal fibrosis compared with wild-type mice. Furthermore, the expression of α-smooth muscle actin, E-cadherin, fibronectin, and collagen I was suppressed. Tisp40 overexpression aggravated ECM accumulation and EMT in the TGF-ß-stimulated TCMK-1 cell line, whereas the opposite occurred in cells treated with small interfering RNA (siRNA) targeting Tisp40. Importantly, it is changes in the Smad pathway that attenuate renal fibrosis. CONCLUSION: These findings suggest that Tisp40 plays a critical role in the TGF-ß/ Smads pathway involved in this process. Hence, Tisp40 could be a useful therapeutic target in the fight against renal tubulointerstitial fibrosis.

TGFß/SMAD/microRNA-486-3p Signaling Axis Mediates Keratin 17 Expression and Keratinocyte Hyperproliferation in Psoriasis.

Keratin 17 (K17) is strongly expressed in psoriatic lesions but not healthy skin, and plays a crucial role in disease pathogenesis. The mechanism of aberrant K17 expression in psoriasis has not been fully elucidated. MicroRNAs are short, single-stranded, noncoding RNAs that play important roles in regulating gene expression. Psoriasis exhibits a specific microRNA expression profile distinct from that of healthy skin. In this study, we showed that miR-486-3p was markedly reduced in psoriatic epidermis and negatively correlated with the psoriasis area and severity index score. Its expression repressed K17 protein expression and decreased proliferation in a keratinocyte cell line overexpressing K17 (LV K17) compared with controls. Our data indicated that miR-486-3p was regulated by a transforming growth factor-ß (TGFß)/SMAD pathway and possibly mediated the downregulation of K17 protein in TGFß-treated keratinocytes. Finally, the decreased expression of TGFß receptor I in psoriatic epidermis inactivated the TGFß/SMAD pathway, leading to K17 overexpression and cell proliferation. Collectively, our findings demonstrated that a TGFß/SMAD/miR-486-3p signaling axis in keratinocytes regulated K17 expression and cell proliferation. We conclude that the loss of miR-486-3p in psoriatic epidermis leads to K17 protein overexpression and contributes to the pathogenesis of psoriasis. Overexpression of miR-486-3p may therefore be a therapeutic option for psoriasis.

Dioxinodehydroeckol Enhances the Differentiation of Osteoblasts by Regulating the Expression of Phospho-Smad1/5/8.

Lack of bone formation-related health problems are a major problem for the aging population in the modern world. As a part of the ongoing trend of developing natural substances that attenuate osteoporotic bone loss conditions, dioxinodehydroeckol (DHE) from edible brown alga Ecklonia cava was tested for its effects on osteoblastogenic differentiation in MC3T3-E1 pre-osteoblasts. DHE was observed to successfully enhance osteoblast differentiation, as indicated by elevated cell proliferation, alkaline phosphatase activity, intracellular cell mineralization, along with raised levels of osteoblastogenesis indicators at the concentration of 20 µM. Results suggested a possible intervening of DHE on the bone morphogenetic protein (BMP) signaling pathway, according to elevated protein levels of BMP-2, collagen-I, and Smads. In addition, the presence of DHE was also able to raise the phosphorylated extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) levels which are also activated by the BMP signaling pathway. In conclusion, DHE is suggested to be a potential bioactive compound against bone loss that could enhance osteoblastogenesis with a suggested BMP pathway interaction.

The GSK3ß inhibitor BIS I reverts YAP-dependent EMT signature in PDAC cell lines by decreasing SMADs expression level.

The Yes-associated protein, YAP, is a transcriptional co-activator, mediating the Epithelial to Mesenchymal Transition program in pancreatic ductal adenocarcinoma (PDAC). With the aim to identify compounds that can specifically modulate YAP functionality in PDAC cell lines, we performed a small scale, drug-based screening experiment using YAP cell localization as the read-out. We identified erlotinib as an inducer of YAP cytoplasmic localization, an inhibitor of the TEA luciferase reporter system and the expression of the bona fide YAP target gene, Connective Tissue Growth Factor CTGF. On the other hand, BIS I, an inhibitor of PKCδ and GSK3ß, caused YAP accumulation into the nucleus. Activation of ß-catenin reporter and interfering experiments show that inhibition of the PKCδ/GSK3ß pathway triggers YAP nuclear accumulation inducing YAP/TEAD transcriptional response. Inhibition of GSK3ß by BIS I reduced the expression levels of SMADs protein and reduced YAP contribution to EMT. Notably, BIS I reduced proliferation, migration and clonogenicity of PDAC cells in vitro, phenocopying YAP genetic down-regulation. As shown by chromatin immunoprecipitation experiments and YAP over-expressing rescue experiments, BIS I reverted YAP-dependent EMT program by modulating the expression of the YAP target genes E-cadherin, vimentin, CTGF and of the newly identified target, CD133. In conclusion, we identified two different molecules, erlotinib and BIS I, modulating YAP functionality although via different mechanisms of action, with the second one specifically inhibiting the YAP-dependent EMT program in PDAC cell lines.

Attenuation of liver fibrosis by herbal compound 861 via upregulation of BMP-7/Smad signaling in the bile duct ligation model rat.

Herbal compound 861 (Cpd 861) exerts an anti-fibrotic effect in patients with hepatic fibrosis; however, the anti-fibrotic mechanism has yet to be fully elucidated. The present study aimed to explore the mechanistic basis for the anti-fibrotic effect, with a focus on bone morphogenetic protein 7 (BMP-7)/Smad signaling in a bile duct ligation (BDL)-induced liver fibrosis rat model. Following the induction of hepatic fibrosis, rats induced by BDL were treated with 9 g/kg Cpd 861 daily or an equal volume of saline for 28 days. Serum samples were prepared for monitoring the levels of alanine transaminase, aspartate transaminase and total bilirubin, and direct bilirubin analyses and liver samples were used to investigate gene expression, protein localization and protein expression analysis using real­time quantitative polymerase chain reaction, immunohistochemistry and western blotting. The results revealed the attenuation of liver fibrosis by Cpd 861 in the histological and biochemical experiments. BMP­7 and phospho (p)­Smad1/5/8 were localized predominantly in the cytoplasm of hepatocytes. In comparison with the saline­treated BDL rats, Cpd 861 markedly upregulated the gene expression of BMP­7 and Smad5, as well as the protein expression of BMP­7 and Smad1/5. In addition, p-Smad1/5/8 protein expression was markedly increased by Cpd 861 in the BDL model. These results indicated that Cpd 861 alleviates hepatic fibrosis possibly via the upregulation and activation of BMP-7/Smad signaling in hepatic fibrotic rats.

Bergenin ameliorates diabetic nephropathy in rats via suppressing renal inflammation and TGF-ß1-Smads pathway.

CONTEXT: Diabetic nephropathy (DN) is a serious complication of diabetes. Bergenin (BEG) was previously confirmed to be effective in treating type 2 diabetes in rats. OBJECTIVE: The objective of this study was to investigate the effects of BEG on renal function in diabetic rats, and meanwhile explore the molecular mechanism. METHODS: DN was induced in rats by a single intraperitoneal injection of streptozotocin. The renal function was evaluated by serum creatinine (SCr), blood urea nitrogen (BUN), urinary albumin and renal histopathology. The proliferation of mesangial cells (MCs) was assayed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H tetrazolium bromide. The production of inflammatory cytokines was detected by ELISA kits, and the levels of Smads were measured by western blotting. RESULTS AND CONCLUSION: In DN rats, there were significantly increased levels of SCr, BUN, urinary albumin, plasma glucose and renal index. The histological changes in diabetic kidney revealed noteworthy focal mesangial matrix expansion. In vitro experiment, high glucose markedly promoted MCs proliferation. However, treatment with BEG obviously normalized these functional parameters, improved diabetic histological changes in vivo and inhibited MCs' proliferation in vitro. Moreover, the levels of tumor necrosis factor-alpha, interleukin-1 (IL-1) and IL-6 in BEG-treated renal tissue and MCs were both reduced. Finally, it showed that BEG markedly reduced transforming growth factor-ß1 (TGF-ß1) production, down-regulated p-Smad2/3 expression and promoted Smad7 expression both in vivo and in vitro. In conclusion, BEG exerts the effective protective role against kidney injuries of diabetic rat, in which the underlying mechanisms are associated with reducing renal inflammation and blocking TGF-ß1-Smads pathway.

Transforming growth factor-ß1 SMAD effectors and medial cell number in ascending aorta diseases.

In ascending aorta aneurysms and dissections, the extracellular matrix is degraded. Transforming growth factor (TGF)-ß1 modulates its synthesis. The production and presence of SMADs, intracellular effectors of TGF-ß1 signaling, were analyzed in patients with these diseases. To verify whether medial cells are lost, their total numbers were computed. Ascending aorta samples from 19 patients and 18 controls underwent immunoperoxidase reactions to SMADs 2, 3, 4, and 7. Positive and negative cells were counted, and total numbers of cells and positive/total ratios were calculated. Samples from other 14 patients and 7 normal controls were used for the quantification of SMAD3, SMAD4, and SMAD7 mRNA. For SMAD4, both mRNA (2.36 vs. 0.37, P=.03) and ratio of positive cells (0.94 vs. 0.73, P=.02) are increased in patients with ascending aortic diseases. SMAD3 mRNA was also increased (1.19 vs. 0.20, P=.05). The cell ratios of this and the other SMADs, SMAD7 mRNA, and the total cell count did not differ between groups. In conclusion, in ascending aortic aneurysms and dissections, there is an increase in SMAD4, implicated in extracellular matrix production, possibly as an attempt to compensate for extracellular matrix deficiency. Lost medial cells are replaced, since their number is not diminished.

Advanced glycation end-products accelerate the cardiac aging process through the receptor for advanced glycation end-products/transforming growth factor-ß-Smad signaling pathway in cardiac fibroblasts.

AIMS: The current study was carried out to evaluate the effect of advanced glycation end-products (AGE) on cardiac aging and to explore its underlying mechanisms. METHODS: Neonatal rat cardiac fibroblasts were cultured and divided into four groups: control; AGE; AGE + receptor for AGE antibody and AGE + SB431542 (transforming growth factor-ß [TGF-ß]/Smad signaling pathway inhibitor, 10 µmol/L) group. After being cultured for 48 h, the cells were harvested and the senescence-associated beta-galactosidase expression was analyzed. Then the level of p16, TGF-ß, Smad/p-smad and matrix metalloproteinases-2 was evaluated by western blot. RESULTS: Significantly increased senescence-associated beta-galactosidase activity as well as p16 level was observed in the AGE group. Furthermore, AGE also significantly increased the TGF-ß1, p-smad2/3 and metalloproteinases-2 expression in cardiac fibroblasts (all P < 0.01). Meanwhile, either pretreatment with receptor for AGE-Ab or SB431542 significantly inhibited the upregulated cardiac senescence (beta-galactosidase activity and P16) and fibrosis-associated (TGF-ß1, p-smad2/3 and metalloproteinases-2) markers induced by AGE. CONCLUSIONS: Taken together, all these results suggested that AGE are an important factor for cardiac aging and fibrosis, whereas the receptor for AGE and TGF-ß/Smad signaling pathway might be involved in the AGE-induced cardiac aging process.

Aluminum trichloride inhibits osteoblast mineralization via TGF-ß1/Smad signaling pathway.

Osteoporosis is a major global public health problem. Aluminum (Al) exposure inhibits osteoblast mineralization and induces osteoporosis. However, the exact mechanism is not fully understood. The transforming growth factor ß1 (TGF-ß1)/Smad pathway is a major signaling cascade in regulating osteoblast mineralization. To investigate whether TGF-ß1/Smad signaling pathway was involved in the Al-induced inhibition of osteoblast mineralization, osteoblasts were cultured and exposed to different concentrations of aluminum trichloride (AlCl3) (containing 0, 0.01, 0.02 and 0.04 mg/mL Al(3+)) for 24 h. We found that mineralized matrix nodules, mRNA expressions of alkaline phosphatase (ALP), type I collagen (Col I), TGF-ß1, TGF-ß type I receptor, TGF-ß type II receptor and Smad4, protein expressions of TGF-ß1 and p-Smad2/3, Smad2/3/4 trimeric complex were all decreased, whereas the mRNA expressions of Smad7 were increased in the AlCl3-treated groups compared with those in control. In conclusion, these results indicated that AlCl3 inhibited osteoblast mineralization via TGF-ß1/Smad signaling pathway in rat osteoblasts. Our findings could provide novel insights into the mechanisms of action of AlCl3 in osteoporosis.

BMP4 inhibits myogenic differentiation of bone marrow-derived mesenchymal stromal cells in mdx mice.

BACKGROUND AIMS: Bone marrow-derived mesenchymal stromal cells (BMSCs) are a promising therapeutic option for treating Duchenne muscular dystrophy (DMD). Myogenic differentiation occurs in the skeletal muscle of the mdx mouse (a mouse model of DMD) after BMSC transplantation. The transcription factor bone morphogenic protein 4 (BMP4) plays a crucial role in growth regulation, differentiation and survival of many cell types, including BMSCs. We treated BMSCs with BMP4 or the BMP antagonist noggin to examine the effects of BMP signaling on the myogenic potential of BMSCs in mdx mice. METHODS: We added BMP4 or noggin to cultured BMSCs under myogenic differentiation conditions. We then injected BMP4- or noggin-treated BMSCs into the muscles of mdx mice to determine their myogenic potential. RESULTS: We found that the expression levels of desmin and myosin heavy chain decreased after treating BMSCs with BMP4, whereas the expression levels of phosphorylated Smad, a downstream target of BMP4, were higher in these BMSCs than in the controls. Mdx mouse muscles injected with BMSCs pretreated with BMP4 showed decreased dystrophin expression and increased phosphorylated Smad levels compared with muscles injected with non-treated BMSCs. The opposite effects were seen after pretreatment with noggin, as expected. CONCLUSIONS: Our results identified BMP/Smad signaling as an essential negative regulator of promyogenic BMSC activity; inhibition of this pathway improved the efficiency of BMSC myogenic differentiation, which suggests that this pathway might serve as a target to regulate BMSC function for better myogenic differentiation during treatment of DMD and degenerative skeletal muscle diseases.

Ski prevents TGF-ß-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-ß (TGF-ß) signaling is a crucial inducer of EMT in various types of cancer. Ski is an important negative regulator of TGF-ß signaling, which interacts with SMADs to repress TGF-ß 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-ß-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-ß 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-ß1 stimulation, we did not observe any effect of Ski on TGF-ß-induced EMT, and invasion in Ski-silenced and overexpressed A549 cells. In conclusion, our findings suggest that Ski represses TGF-ß-induced EMT and invasion by inhibiting SMAD-dependent signaling in NSCLC.