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At least 1,333 records · Page 74

Lack of TAK1 in dendritic cells inhibits the contact hypersensitivity response induced by trichloroethylene in local lymph node assay

Trichloroethylene (TCE) is a ubiquitous environmental contaminant. Occupational TCE exposure has been associated with severe, generalized contact hypersensitivity (CHS) skin disorder. The development of CHS depends on innate and adaptive immune functions. Transforming growth factor-β activated kinase-1 (TAK1) controls the survival of dendritic cells (DCs) that affect the immune system homeostasis. We aimed to investigate the role of TAK1 activity in DC on TCE-induced CHS response. Control mice and DC-specific TAK1 deletion mice were treated with 80% (v/v) TCE using local lymph node assay (LLNA) to establish a TCE-induced CHS model. The draining lymph nodes (DLNs) were excised and the lymphocytes were measure for proliferation by BrdU-ELISA, T-cell phenotype analysis by flow cytometry and signaling pathway activation by western blot. The ears were harvested for histopathological analysis. Control mice in the 80% TCE group displayed an inflammatory response in the ears, increased lymphocyte proliferation, elevated regulatory T-cell and activated T-cell percentages, and more IFN-γ producing CD8{sup +} T cells in DLNs. In contrast to control mice, DC-specific TAK1 deletion mice in the 80% TCE group showed an abolished CHS response and this was associated with defective T-cell expansion, activation and IFN-γ production. This effect may occur through Jnk and NF-κB signaling pathways. Overall, this study demonstrates a pivotal role of TAK1 in DCs in controlling TCE-induced CHS response and suggests that targeting TAK1 function in DCs may be a viable approach to preventing and treating TCE-related occupational health hazards. - Highlights: • Lack of TAK1 in DC caused an abolished TCE-induced CHS response. • TAK1 in DCs was essential to maintain the homeostasis of T cells in TCE-induced CHS. • Intact TAK1 in DCs was critical to promote T-cell priming in TCE-induced CHS. • DC-specific TAK1 deficiency abolished the TCE-mediated phosphorylation of Jnk.

60 APPLIED LIFE SCIENCES↗

Di-(2-ethylhexyl) phthalate could disrupt the insulin signaling pathway in liver of SD rats and L02 cells via PPARγ

Di-(2-ethylhexyl)-phthalate (DEHP), a ubiquitous industrial pollutant in our daily life, has been reported to cause adverse effects on glucose homeostasis and insulin sensitivity in epidemiological studies previously. Recently, it has been reported to be an endocrine disrupter and ligand to peroxisome proliferator activated receptor, which could influence the homeostasis of liver metabolic systems and contribute to the development of type-2 diabetes. However, the potential mechanisms are not known yet. This study was designed to solve these problems with male SD rats and normal human hepatocyte line, L02 cells, exposed to DEHP for toxicological experiments. Adult male SD rats were divided into four groups, normal group fed with regular diets and three DEHP-treated groups (dissolved in olive oil at doses of 0.05, 5 and 500 mg/kg body weight, respectively, once daily through gastric intubations for 15 weeks). L02 cells were divided into 6 groups, normal group with 5, 10, 25, 50, and 100 μmol/l DEHP groups. DEHP-exposed rats exhibited significant liver damage, glucose tolerance, and insulin tolerance along with reduced expression of insulin receptor and GLUT4 proteins in the liver tissues. The results of in vitro experiments could determine that the DEHP-induced activation of peroxisome proliferator activated receptor γ (PPARγ) played a key role in the production of oxidative stress and down-regulated expression of insulin receptor and GLUT4 proteins in L02 cells. This conclusion could be supported by the results of in vitro experiments, in which the cells were exposed to DEHP with GW9662 (PPARγ inhibitor). In general, these results highlight the key role of PPARγ in the process of insulin resistance induced by DEHP. - Highlights: • DEHP exacerbates insulin resistance both in liver tissues and cells. • Expression of insulin receptor and GLUT4 were altered with PPARγ. • DEHP can induce oxidative stress to disrupt the metabolic homeostasis. • The dose of exposed DEHP is closed to daily exposure by human. • Determine the key role of PPARγ to insulin resistance.

60 APPLIED LIFE SCIENCES↗

Cadmium stimulates metastasis-associated phenotype in triple-negative breast cancer cells through integrin and β-catenin signaling

Cadmium (Cd) is a carcinogenic heavy metal which is implicated in breast cancer development. While the mechanisms of Cd-induced breast cancer initiation and promotion have been studied, the molecular processes involved in breast cancer progression remain to be investigated. The purpose of the present study was to evaluate the influence of Cd on metastasis-associated phenotypes, such as cell adhesion, migration, and invasion in triple-negative breast cancer cells. Treatment of MDA-MB-231 cells with 1 μM Cd increased cell spreading and cell migration. This was associated with the activation of integrin β1, FAK, Src, and Rac1. Treatment with Cd also inhibited GSK3β activity and induced T-cell factor/lymphoid enhancer factor (TCF/LEF) transcription, indicating the involvement of β-catenin signaling. Furthermore, treatment with 3 μM Cd for 4 weeks increased the expression of β-catenin and enhanced TCF/LEF-mediated transcription. Furthermore, enhanced expressions of integrins α5 and β1, paxillin, and vimentin indicated that prolonged Cd treatment reorganized the cytoskeleton, which aided malignancy, as evidenced by enhanced matrix metalloprotease 2/9 (MMP2/9) secretion and cell invasion. Prolonged Cd treatment also caused an increase in cell growth. Together, these results indicate that Cd alters key signaling processes involved in the regulation of cytoskeleton to enhance cancer cell migration, invasion, adhesion, and proliferation. - Highlights: • Cd enhances cell adhesion in triple-negative breast cancer cells through integrin activation. • Inhibition of GSK3β by Cd leads to activation of β-catenin pathway. • Accumulation of β-catenin facilitates TCF/LEF-mediated-transcription. • Prolonged Cd treatment stimulates cell migration, invasion, and proliferation.

60 APPLIED LIFE SCIENCES↗

Staphylococcal enterotoxin C2 mutant drives T lymphocyte activation through PI3K/mTOR and NF-ĸB signaling pathways

Staphylococcal enterotoxin C2 (SEC2), a superantigen, causes rapid clonal expansion of lymphocytes and secretion of T cell growth factors, leading to a severe inflammatory response within tissues. Although previous studies have shown that ST-4, a SEC2 mutant with enhanced recognition of Vβ regions of T-cell receptors (TCRVβ), can activate an increased number of T cells and produce more cytokines than SEC2. However, the signaling mechanisms of SEC2/ST-4-mediated immune activation have not been addressed. In this study, we showed that the phosphatidylinositide-3-kinase (PI-3K) inhibitor LY294002, mammalian target of rapamycin (mTOR) inhibitor rapamycin, and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) inhibitor Bay11-7085 could suppress SEC2/ST-4-induced proliferation, CD69/CD25 expression, cell-cycle progression, and IL-2 production in BALB/c mouse splenocytes. In addition, we observed significantly upregulated expression of p70S6K, cyclin E, cyclin D3, and NF-ĸB/p65, but downregulated expression of p27kip during SEC2/ST-4-driven T cells activation. However, SEC2/ST-4-induced changes in cell cycle and PI3K/mTOR signaling were significantly relieved by either LY294002 or rapamycin, and the induction of NF-ĸB/p65 induced was significantly downregulated by Bay11-7085. Moreover, we found that IL-2 secretion was positively associated with p65 expression in a time- and dose-dependent manner. Taken together, our findings demonstrate the involvement of PI3K/mTOR and NF-κB signaling pathways in SEC2/ST-4-induced T cell activation. ST-4 intensifies PI3K/mTOR and NF-ĸB signaling transduction, ultimately leading to enhance T cell activation. These results provide a theoretical mechanism for future immunotherapy using ST-4. - Graphical abstract: SEC2/ST-4 drives T lymphocyte activation through PI3K/mTOR and NF-ĸB signaling pathways - Highlights: • SEC2/ST-4 induces lymphocyte proliferation, CD69, CD25 expression, IL-2 secretion. • SEC2/ST-4 upregulates S6K, cyclin E/D3, p65 expression at mRNA and protein levels. • SEC2/ST-4 downregulates p27kip expression at mRNA and protein levels. • PI3K/mTOR and NF-ĸB inhibitors reverse molecules expression induced by SEC2/ST-4. • ST-4 exhibits higher efficiency than SEC2 in PI3K/mTOR and NF-ĸB pathways.

60 APPLIED LIFE SCIENCES↗

Preservation of high glycolytic phenotype by establishing new acute lymphoblastic leukemia cell lines at physiologic oxygen concentration

Cancer cells typically exhibit increased glycolysis and decreased mitochondrial oxidative phosphorylation, and they continue to exhibit some elevation in glycolysis even under aerobic conditions. However, it is unclear whether cancer cell lines employ a high level of glycolysis comparable to that of the original cancers from which they were derived, even if their culture conditions are changed to physiologically relevant oxygen concentrations. From three childhood acute lymphoblastic leukemia (ALL) patients we established three new pairs of cell lines in both atmospheric (20%) and physiologic (bone marrow level, 5%) oxygen concentrations. Cell lines established in 20% oxygen exhibited lower proliferation, survival, expression of glycolysis genes, glucose consumption, and lactate production. Interestingly, the effects of oxygen concentration used during cell line initiation were only partially reversible when established cell cultures were switched from one oxygen concentration to another for eight weeks. These observations indicate that ALL cell lines established at atmospheric oxygen concentration can exhibit relatively low levels of glycolysis and these levels are semi-permanent, suggesting that physiologic oxygen concentrations may be needed from the time of cell line initiation to preserve the high level of glycolysis commonly exhibited by leukemias in vivo. - Highlights: • Establishing new ALL cell lines in 5% oxygen resulted in higher glycolytic expression and function. • Establishing new ALL cell lines in 5% oxygen resulted in higher proliferation and lower cell death. • The divergent metabolic phenotypes selected in 5% and 20% oxygen are semi-permanent.

60 APPLIED LIFE SCIENCES↗

MiR-218 Mediates tumorigenesis and metastasis: Perspectives and implications

MicroRNAs (miRNAs) are a class of small non-coding RNAs that negatively regulate gene expression at the post-transcriptional level. As a highly conserved miRNA across a variety of species, microRNA-218 (miR-218) was found to play pivotal roles in tumorigenesis and progression. A group of evidence has demonstrated that miR-218 acts as a tumor suppressor by targeting many oncogenes related to proliferation, apoptosis and invasion. In this review, we provide a complex overview of miR-218, including its regulatory mechanisms, known functions in cancer and future challenges as a potential therapeutic target in human cancers. - Highlights: • miR-218 is frequently down regulated in multiple cancers. • miR-218 plays pivotal roles in carcinogenesis. • miR-218 mediates proliferation, apoptosis, metastasis, invasion, etc. • miR-218 mediates tumorigenesis and metastasis via multiple pathways.

60 APPLIED LIFE SCIENCES↗

The novel HSP90 inhibitor NVP-AUY922 shows synergistic anti-leukemic activity with cytarabine in vivo

HSP90 is a molecular chaperone essential for stability, activity and intracellular sorting of many proteins, including oncoproteins, such as tyrosine kinases, transcription factors and cell cycle regulatory proteins. Therefore, inhibitors of HSP90 are being investigated for their potential as anti-cancer drugs. Here we show that the HSP90 inhibitor NVP-AUY922 induced degradation of the fusion oncoprotein FOP2-FGFR1 in a human acute myeloid leukemia (AML) cell line, KG-1a. Concordantly, downstream signaling cascades, such as STAT1, STAT3 and PLCγ were abrogated. At concentrations that caused FOP2-FGFR1 degradation and signaling abrogation, NVP-AUY922 treatment caused significant cell death and inhibition of proliferation of KG-1a cells in vitro. In an animal model for AML, NVP-AUY922 administrated alone showed no anti-leukemic activity. However, when NVP-AUY922 was administered in combination with cytarabine, the two compounds showed significant synergistic anti-leukemic activity in vivo. Thus NVP-AUY922 and cytarabine combination therapy might be a prospective strategy for AML treatment. - Highlights: • NVP-AUY922 induces degradation of the oncoprotein FOP2-FGFR1 in KG-1a leukemia cells. • NVP-AUY922 induces cell death and inhibition of proliferation of KG-1a cells. • NYP-AUY922 combined with cytarabine shows synergistic anti-leukemic activity in vivo.

60 APPLIED LIFE SCIENCES↗

Down-regulation of hTERT and Cyclin D1 transcription via PI3K/Akt and TGF-β pathways in MCF-7 Cancer cells with PX-866 and Raloxifene

Human telomerase reverse transcriptase (hTERT) is the catalytic and limiting component of telomerase and also a transcription factor. It is critical to the integrity of the ends of linear chromosomes and to the regulation, extent and rate of cell cycle progression in multicellular eukaryotes. The level of hTERT expression is essential to a wide range of bodily functions and to avoidance of disease conditions, such as cancer, that are mediated in part by aberrant level and regulation of cell cycle proliferation. Value of a gene in regulation depends on its ability to both receive input from multiple sources and transmit signals to multiple effectors. The expression of hTERT and the progression of the cell cycle have been shown to be regulated by an extensive network of gene products and signaling pathways, including the PI3K/Akt and TGF-β pathways. The PI3K inhibitor PX-866 and the competitive estrogen receptor ligand raloxifene have been shown to modify progression of those pathways and, in combination, to decrease proliferation of estrogen receptor positive (ER+) MCF-7 breast cancer cells. We found that combinations of modulators of those pathways decreased not only hTERT transcription but also transcription of additional essential cell cycle regulators such as Cyclin D1. By evaluating known expression profile signatures for TGF-β pathway diversions, we confirmed additional genes such as heparin-binding epidermal growth factor-like growth factor (HB EGF) by which those pathways and their perturbations may also modify cell cycle progression. - Highlights: • PX-866 and raloxifene affect the PI3K/Akt and TGF-β pathways. • PX-866 and raloxifene down-regulate genes up-regulated in cancer. • PX-866 and raloxifene decrease transcription of hTERT and Cyclin D1. • Pathological transcription signatures can identify new defense mechanisms.

60 APPLIED LIFE SCIENCES↗

ERα inhibited myocardin-induced differentiation in uterine fibroids

Uterine fibroids, also known as uterine leiomyomas, are a benign tumor of the human uterus and the commonest estrogen-dependent benign tumor found in women. Myocardin is an important transcriptional regulator in smooth and cardiac muscle development. The role of myocardin and its relationship with ERα in uterine fibroids have barely been addressed. We noticed that the expression of myocardin was markedly reduced in human uterine fibroid tissue compared with corresponding normal or adjacent myometrium tissue. Here we reported that myocardin induced the transcription and expression of differentiation markers SM22α and alpha smooth muscle actin (α-SMA) in rat primary uterine smooth muscle cells (USMCs) and this effect was inhibited by ERα. Notably, we showed that, ERα induced expression of proliferation markers PCNA and ki-67 in rat primary USMCs. We also found ERα interacted with myocardin and formed complex to bind to CArG box and inhibit the SM22α promoter activity. Furthermore, ERα inhibited the transcription and expression of myocardin, and reduced the levels of transcription and expression of downstream target SM22α, a SMC differentiation marker. Our data thus provided important and novel insights into how ERα and myocardin interact to control the cell differentiation and proliferation of USMCs. Thus, it may provide potential therapeutic target for uterine fibroids.

60 APPLIED LIFE SCIENCES↗

Combination of exogenous cell transplantation and 5-HT{sub 4} receptor agonism induce endogenous enteric neural crest-derived cells in a rat hypoganglionosis model

Enteric neural crest-derived cells (ENCCs) can migrate into endogenous ganglia and differentiate into progeny cells, and have even partially rescued bowel function; however, poor reliability and limited functional recovery after ENCC transplantation have yet to be addressed. Here, we investigated the induction of endogenous ENCCs by combining exogenous ENCC transplantation with a 5-HT{sub 4} receptor agonist mosapride in a rat model of hypoganglionosis, established by benzalkonium chloride treatment. ENCCs, isolated from the gut of newborn rats, were labeled with a lentiviral eGFP reporter. ENCCs and rats were treated with the 5-HT{sub 4} receptor agonist/antagonist. The labeled ENCCs were then transplanted into the muscular layer of benzalkonium chloride-treated colons. At given days post-intervention, colonic tissue samples were removed for histological analysis. ENCCs and neurons were detected by eGFP expression and immunoreactivity to p75{sup NTR} and peripherin, respectively. eGFP-positive ENCCs and neurons could survive and maintain levels of fluorescence after transplantation. With longer times post-intervention, the number of peripherin-positive cells gradually increased in all groups. Significantly more peripherin-positive cells were found following ENCCs plus mosapride treatment, compared with the other groups. These results show that exogenous ENCCs combined with the 5-HT{sub 4} receptor agonist effectively induced endogenous ENCCs proliferation and differentiation in a rat hypoganglionosis model. - Highlights: • Survival and differentiation of exogenous ENCCs in treated colons. • With longer times post-intervention, the number of ENCCs and their progeny cells gradually increased. • Exogenous ENCCs combined with the 5-HT4 receptor agonist ffectively induced ENCCs proliferation and differentiation.

60 APPLIED LIFE SCIENCES↗

The atypical Rho GTPase RhoD is a regulator of actin cytoskeleton dynamics and directed cell migration

RhoD belongs to the Rho GTPases, a protein family responsible for the regulation and organization of the actin cytoskeleton, and, consequently, many cellular processes like cell migration, cell division and vesicle trafficking. Here, we demonstrate that the actin cytoskeleton is dynamically regulated by increased or decreased protein levels of RhoD. Ectopic expression of RhoD has previously been shown to give an intertwined weave of actin filaments. We show that this RhoD-dependent effect is detected in several cell types and results in a less dynamic actin filament system. In contrast, RhoD depletion leads to increased actin filament-containing structures, such as cortical actin, stress fibers and edge ruffles. Moreover, vital cellular functions such as cell migration and proliferation are defective when RhoD is silenced. Taken together, we present data suggesting that RhoD is an important component in the control of actin dynamics and directed cell migration. - Highlights: • Increased RhoD expression leads to loss of actin structures, e.g. stress fibers and gives rise to decreased actin dynamics. • RhoD knockdown induces various actin-containing structures such as edge ruffles, stress fibers and cortical actin, in a cell-type specific manner. • RhoD induces specific actin rearrangements depending on its subcellular localization. • RhoD knockdown has effects on cellular processes, such as directed cell migration and proliferation.

60 APPLIED LIFE SCIENCES↗

Modulation of hepatic stellate cells and reversibility of hepatic fibrosis

Hepatic fibrosis (HF) is the pathological component of a variety of chronic liver diseases. Hepatic stellate cells (HSC) are the main collagen-producing cells in the liver and their activation promotes HF. If HSC activation and proliferation can be inhibited, HF occurrence and development can theoretically be reduced and even reversed. Over the past ten years, a number of studies have addressed this process, and here we present a review of HSC modulation and HF reversal. - Highlights: • We present a review of the modulation of hepatic stellate cells (HSC) and reversibility of hepatic fibrosis (HF). • HSC are the foci of HF occurrence and development, HF could be prevented and treated by modulating HSC. • If HSC activation and proliferation can be inhibited, HF could theoretically be inhibited and even reversed. • Prevention or reversal of HSC activation, or promotion of HSC apoptosis, immune elimination, and senescence may prevent, inhibit or reverse HF.

60 APPLIED LIFE SCIENCES↗

The role of cardiac energy metabolism in cardiac hypertrophy and failure

In mammalian heart, incessant production of cellular energy is vital for maintaining continuous mechanical pumping function providing the body for oxygen and nutrients. To ensure this essential function, cardiac muscle adapt to increased energy demand or compromised energy supply by reprogramming the network of genes whose products are necessary to match the production of energy to consumption. Failure in this regulation leads to severe cardiac dysfunction and has been associated with cardiac pathogenesis including cardiac hypertrophy, failure and diabetes. Metabolic adaptations are induced by network of transcriptional pathways that are activated by a variety of factors such as hormones, nutrients, second messengers and oxygen. The metabolic phenotype of the heart is maintained by pathways controlling transcriptional regulators, which include peroxisome proliferator-activated receptors, estrogen-related receptors and nuclear respiratory factors, as well as their common coactivator protein peroxisome proliferator-activated receptor γ coactivator 1. These central regulators of gene expression are complemented with factors such as hypoxia inducible factor 1, which is activated in insufficient oxygenation of the tissue. Here, we discuss how these pathways relate to the cardiac metabolism and how they interact with pathways controlling the contractile phenotype of the heart. - Highlights: • Energy metabolic changes are associated with cardiac adaptation and pathogenesis. • Cardiac energy substrate utilisation is controlled by complex transcriptional networks. • Transcriptional pathways controlling heart metabolic and contractile phenotype overlap.

60 APPLIED LIFE SCIENCES↗

miR-429 inhibits metastasis by targeting KIAA0101 in Soft Tissue Sarcoma

Soft tissue sarcomas (STS) are a heterogeneous group of rare tumors with high metastatic potential. There being only a handful of publication on metastasis of STS, we investigated the miRNA mediated target gene regulations in modulating the metastatic processes in this cancer. In this study, we amalgamated gene and miRNA expression profiles of high-grade STS samples with miRNA target predictions and identified miR-429 targeting KIAA0101 as a novel pair, which remain unexplored in STS metastasis. We validated their expression in metastatic fibrosarcoma cell line, HT1080 and performed several functional assays using miRNA mimics and KIAA0101 over-expression vector to confirm their role in metastasis. We observed miR-429 is downregulated in HT1080 cells and acting as an anti-metastatic miRNA that inhibited proliferation, migration, anchorage independent growth and invasion by de-repressing KIAA0101. Moreover, the renilla luciferase reporter assay confirmed that miR-429 targets KIAA0101 by binding to its 3{sup /}UTR and influence its expression. Taken together, our work demonstrated miR-429 mediates deregulation of KIAA0101 by acting as an anti-metastatic miRNA that targets KIAA0101 pro-metastatic gene during metastasis of STS. - Highlights: • miR-429 inhibits metastasis by targeting KIAA0101 in Soft Tissue Sarcoma. • miR-429 suppresses proliferation, migration, anchorage independent growth and invasion in HT1080. • We validated targeting of miR-429 and KIAA0101 by reporter assay. • KIAA0101 overexpression is involved in decreased survival of STS patients.

60 APPLIED LIFE SCIENCES↗

Function and regulation of LAG3 on CD4{sup +}CD25{sup -} T cells in non-small cell lung cancer

LAG3 is a surface molecule found on a subset of immune cells. The precise function of LAG3 appears to be context-dependent. In this study, we investigated the effect of LAG3 on CD4{sup +}CD25{sup -} T cells from non-small cell lung cancer (NSCLC) patients. We found that in the peripheral blood mononuclear cells of NSCLC patients, LAG3 was significantly increased in CD4{sup +} T cells directly ex vivo and primarily in the CD4{sup +}CD25{sup -} fraction, which was regulated by prolonged TCR stimulation and the presence of IL-27. TCR stimulation also increased CD25 expression, but not Foxp3 expression, in LAG3-expressing CD4{sup +}CD25{sup -} cells Compared to LAG3-nonexpressing CD4{sup +}CD25{sup -} cells, LAG3-expressing CD4{sup +}CD25{sup -} cells presented significantly higher levels of PD1 and TIM3, two inhibitory receptors best described in exhausted CD8{sup +} T effector cells. LAG3-expressing CD4{sup +}CD25{sup -} cells also presented impaired proliferation compared with LAG3-nonexpressing CD4{sup +}CD25{sup -} cells but could be partially rescued by inhibiting both PD1 and TIM3. Interestingly, CD8{sup +} T cells co-incubated with LAG3-expressing CD4{sup +}CD25{sup -} cells at equal cell numbers demonstrated significantly lower proliferation than CD8{sup +} T cells incubated alone. Co-culture with CD8{sup +} T cell and LAG3-expressing CD4{sup +}CD25{sup -} T cell also upregulated soluble IL-10 level in the supernatant, of which the concentration was positively correlated with the number of LAG3-expressing CD4{sup +}CD25{sup -} T cells. In addition, we found that LAG3-expressing CD4{sup +}CD25{sup -} T cells infiltrated the resected tumors and were present at higher frequencies of in metastases than in primary tumors. Taken together, these data suggest that LAG3-expressing CD4{sup +}CD25{sup -} T cells represent another regulatory immune cell type with potential to interfere with anti-tumor immunity.

60 APPLIED LIFE SCIENCES↗

1,25(OH)2D3 attenuates pulmonary arterial hypertension via microRNA-204 mediated Tgfbr2/Smad signaling

Highlights: • miRNA-204 is significantly lower in hypoxic pulmonary hypertension. • miRNA-204 is involved in the development of pulmonary hypertension. • 1,25(OH){sub 2}D{sub 3} significantly prevented the development of PAH by blocking the Tgfbr2/Smad signaling. • 1,25(OH){sub 2}D{sub 3} reduced pulmonary hypertension mediated by increased the level of miRNA-204. • miRNA-204 strengthened the anti-PAH function of 1,25(OH){sub 2}D{sub 3} by targeting Tgfbr2. Pulmonary arterial hypertension (PAH) is a devastating disease characterized by high pulmonary artery pressure. It is reported that microRNA-204 (miR-204) plays an important role in the development of PAH. Calcitriol [1,25-dihydroxyvitamin D3, 1,25(OH){sub 2}D{sub 3}] mediates multiple pathophysiological processes. The aim of the current study was to explore the role of 1,25(OH){sub 2}D{sub 3} in PAH. PAH was induced in rats and rat pulmonary arterial endothelial cells (PAECs) were isolated as in vitro PAH model. The mean pulmonary artery pressure, morphologic changes, and expressions of transforming growth factor-beta1 (Tgfbr2), Smad2/7, alpha smooth muscle actin (α-SMA), and p21 were then measured. Furthermore, the effect of 1,25(OH){sub 2}D{sub 3} on rat PAECs with or without hypoxia treatment was also assessed by measuring the proliferation, migration, and cell cycle distribution of PAECs. The potential targets of miR-204 were also predicted and validated with a dual-luciferase reporter system. Then the role of miR-204 and Tgfbr2 in the anti-PAH effect of 1,25(OH){sub 2}D{sub 3} was further explored by modulating the expression of the two genes. The overall pulmonary hypertension and hypoxia-induced proliferation and migration of PAECs were attenuated by administration of 1,25(OH){sub 2}D{sub 3}, which was associated with the suppressed expressions of Tgfbr2, α-SMA, and Smad7 and induced expressions of miR-204, p21 and Smad2 both in vitro and in vivo. Moreover, the luciferase reporter assay identified Tgfbr2 as a novel direct target of miR-204. Both overexpression of miR-204 and inhibition of Tgfbr2 would strengthen the effect of 1,25(OH){sub 2}D{sub 3} administration. Findings outlined in the current study demonstrated that 1,25(OH){sub 2}D{sub 3} was a promising therapeutic modality for treatment of PAH, function of which was exerted through miR-204 mediated Tgfbr2 signaling.

60 APPLIED LIFE SCIENCES↗

Potential role of MG53 in the regulation of transforming-growth-factor-β1-induced atrial fibrosis and vulnerability to atrial fibrillation

Highlights: • MG53 is expressed in human atrium and associated with AF. • MG53 could regulate TGF-β1/Smad pathway to induce atrial fibrosis. • Exogenous TGF-β1 suppresses expression of MG53. • MG53 could serve as a promising target agent for atrial fibrosis induced by the TGF-β1/Smad pathway in patients with AF. Atrial fibrosis plays a critical role in atrial fibrillation (AF) by the transforming growth factor (TGF)-β1/Smad pathway. The disordered differentiation, proliferation, migration and collagen deposition of atrial fibroblasts play significant roles in atrial fibrosis. Mitsugumin (MG)53 is predominantly expressed in myocardium of rodents and has multiple biological functions. However, the role of MG53 in cardiac fibrosis remains unclear. This study provided clinical and experimental evidence for the involvement of MG53 in atrial fibrosis in humans and atrial fibrosis phenotype in cultured rat atrial fibroblasts. In atrial tissue from patients we demonstrated that MG53 was expressed in human atrium. Expression of MG53 increased with the extent of atrial fibrosis, which could induce AF. In cultured atrial fibroblasts, depletion of MG53 by siRNA caused down-regulation of the TGF-β1/Smad pathway, while overexpression of MG53 by adenovirus up-regulated the pathway. MG53 regulated the proliferation and migration of atrial fibroblasts. Besides, exogenous TGF-β1 suppressed expression of MG53. In conclusion, we demonstrated that MG53 was expressed in human atrium, and may be a potential upstream of the TGF-β1/Smad pathway in human atrium and rat atrial fibroblasts. This suggests that MG53 is a potential regulator of atrial fibrosis induced by the TGF-β1/Smad pathway in patients with AF.

60 APPLIED LIFE SCIENCES↗

Abrogation of Fam20c altered cell behaviors and BMP signaling of immortalized dental mesenchymal cells

Highlights: • Fam20c deficiency decreases the proliferation, mobility and mineralization of mouse immortalized dental mesenchymal cells. • Fam20c deficiency decreases the tooth mineralization, as well as the gene expression on dental mesenchymal differentiation. • Canonical and non-canonical BMP signaling pathways are declined in the mouse Fam20c-deficient dental mesenchyaml cell line. FAM20C mutations compromise the mineralization of skeleton and tooth in both human and mouse. Putatively, the mineralization disorder is attributed to the elevated fibroblast growth factor 23 (FGF23), which reduced the serum phosphorus by suppressing the reabsorption of phosphorus in kidney. Besides the regulation on systemic phosphorus homeostasis, FAM20C was also implicated to regulate cell behaviors and gene expression through a cell-autonomous manner. To identify the primary effects of Fam20c on dental mesenchymal cells, mouse Fam20c-deficient dental mesenchymal cells were generated by removing the floxed alleles from the immortalized mouse Fam20c{sup f/f} dental mesenchymal cells with Cre-expressing lentivirus. The removal of Fam20c exerted no impact on cell morphology, but suppressed the proliferation and mobility of the dental mesenchymal cells. Fam20c deficiency also significantly reduced the expression of Osterix, Runx2, type I Collagen a 1 (Col1a1), Alkaline phosphatase (Alpl) and the members of the small integrin-binding ligand, N-linked glycoprotein (SIBLING) family, but increased Fgf23 expression. Consistently, the in vitro mineralization of Fam20c-deficient dental mesenchymal cells was severely disabled. However, supplements of the non-collagenous proteins from wild type rat dentin failed to rescue the compromised mineralization, suggesting that the roles of FAM20C in tooth mineralization are more than phosphorylating local matrices and regulating systemic phosphorus metabolism. Moreover, the down-regulated BMP signaling pathways in the Fam20c deficient dental mesenchymal cells revealed that the kinase activity of FAM20C might be required to maintain BMP signaling. In summary, our study discloses that Fam20c indeed regulates cell behaviors and cell signaling pathway in a cell-autonomous manner.

60 APPLIED LIFE SCIENCES↗