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Lihua Ding - One of the best experts on this subject based on the ideXlab platform.
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Src-mediated phosphorylation converts FHL1 from tumor suppressor to tumor promoter.
The Journal of cell biology, 2018Co-Authors: Xiang Wang, Jing Zhang, Xiaofan Wei, Yang Yuan, Qingrui Sun, Jun Zhan, Yan Tang, Lihua DingAbstract:FHL1 has been recognized for a long time as a tumor suppressor protein that associates with both the actin cytoskeleton and the transcriptional machinery. We present in this study a paradigm that phosphorylated FHL1 functions as an oncogenic protein by promoting tumor cell proliferation. The cytosolic tyrosine kinase Src interacts with and phosphorylates FHL1 at Y149 and Y272, which switches FHL1 from a tumor suppressor to a cell growth accelerator. Phosphorylated FHL1 translocates into the nucleus, where it binds to the transcription factor BCLAF1 and promotes tumor cell growth. Importantly, the phosphorylation of FHL1 is increased in tissues from lung adenocarcinoma patients despite the down-regulation of total FHL1 expression. Kindlin-2 was found to interact with FHL1 and recruit FHL1 to focal adhesions. Kindlin-2 competes with Src for binding to FHL1 and suppresses Src-mediated FHL1 phosphorylation. Collectively, we demonstrate that FHL1 can either suppress or promote tumor cell growth depending on the status of the sites for phosphorylation by Src.
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FHL1 inhibits the growth of tongue squamous cell carcinoma cells via g1 s cell cycle arrest
Molecular Medicine Reports, 2015Co-Authors: Wei Ren, Lihua Ding, Long Cheng, Panfeng Lian, Xin Guan, Hongyuan Wang, Zhenyang Gao, Xin Huang, Fengjun Xiao, Lisheng WangAbstract:Abstract Four and a half LIM protein 1 (FHL1) has been characterized as a tumor suppressor in various types of tumor. However, the biological function and underlying mechanism of FHL1 in tongue squamous cell carcinoma (TSCC) remain to be elucidated. The present study demonstrated that FHL1 inhibits anchorage‑dependent and ‑independent growth of TSCC cells in vitro and tumor growth in nude mice, as determined by cell proliferation and soft agar assays. Knockdown of FHL1 with FHL1 small interfering RNA (siRNA) promoted tumor growth in nude mice. Mechanistically, flow cytometric analysis showed that knockdown of FHL1 promoted G1/S cell cycle progression. Furthermore, expression of cell cycle‑associated regulators, cyclin D and cyclin E, were detected by western blotting and reverse transcription‑quantitative polymerase chain reaction. Cyclin D and cyclin E were markedly elevated at both the protein and mRNA level in the FHL1 siRNA‑transfected cells. These results suggested that FHL1 has a tumor suppressive role in TSCC and that FHL1 may be a useful target for TSCC gene therapy.
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FHL1 inhibits the growth of tongue squamous cell carcinoma cells via G1/S cell cycle arrest
Molecular medicine reports, 2015Co-Authors: Wei Ren, Lihua Ding, Long Cheng, Panfeng Lian, Xin Guan, Hongyuan Wang, Zhenyang Gao, Xin Huang, Fengjun XiaoAbstract:Abstract Four and a half LIM protein 1 (FHL1) has been characterized as a tumor suppressor in various types of tumor. However, the biological function and underlying mechanism of FHL1 in tongue squamous cell carcinoma (TSCC) remain to be elucidated. The present study demonstrated that FHL1 inhibits anchorage‑dependent and ‑independent growth of TSCC cells in vitro and tumor growth in nude mice, as determined by cell proliferation and soft agar assays. Knockdown of FHL1 with FHL1 small interfering RNA (siRNA) promoted tumor growth in nude mice. Mechanistically, flow cytometric analysis showed that knockdown of FHL1 promoted G1/S cell cycle progression. Furthermore, expression of cell cycle‑associated regulators, cyclin D and cyclin E, were detected by western blotting and reverse transcription‑quantitative polymerase chain reaction. Cyclin D and cyclin E were markedly elevated at both the protein and mRNA level in the FHL1 siRNA‑transfected cells. These results suggested that FHL1 has a tumor suppressive role in TSCC and that FHL1 may be a useful target for TSCC gene therapy.
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Downregulation and growth inhibitory role of FHL1 in lung cancer
International journal of cancer, 2011Co-Authors: Chang Niu, Lihua Ding, Hao Zhang, Long Cheng, Xi Qin, Chaoyang Liang, Juntang Guo, Qunwei Zhang, Bin YuanAbstract:Four and a half Lin-11, Isl-1, Mac-3 (LIM) protein 1 (FHL1) has been linked to carcinogenesis. However, the role of FHL1 in lung cancer remains unclear and the detailed mechanism underlying its tumor suppressive role is poorly understood. The purpose of this study was to examine FHL1 expression in lung cancer patients and to investigate how it was associated with lung cancer cell growth. Immunoblotting and immunohistochemistry showed that FHL1 protein was downregulated in over 90% of 80 lung cancer patients. FHL1 expression was strongly correlated with tumor histological types (p < 10 24 ) and the differentiation of the tumor (p 5 0.002). FHL1 inhibited anchorage-dependent and -independent growth of human lung cancer cell lines. The inhibitory effects of FHL1 on lung cancer cell growth were associated with both the G1 and the G2/M cell cycle arrest concomitant with a marked inhibition of cyclin A, cyclin B1 and cyclin D as well as the induction of the cyclin dependent kinase inhibitors p21 (WAF1/CIP1) and p27 (Kip1). Direct intratumoral injection of an adenovirus expressing FHL1 dramatically suppressed the growth of A549 lung cancer cells in nude mice. Our data suggest that reduced expression of FHL1 may play an important role in the development and progression of lung cancer and that FHL1 may be a useful target for lung cancer gene therapy.
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FHL1 interacts with oestrogen receptors and regulates breast cancer cell growth.
Journal of cellular and molecular medicine, 2009Co-Authors: Lihua Ding, Chang Niu, Yiqiong Zheng, Zhihong Xiong, Yufei Liu, Jing Lin, Huiwei Sun, Ke Huang, Wen YangAbstract:Four and a half LIM protein 1 (FHL1) belongs to the Lin-1, Isl-1 and Mec-3 (LIM)-only protein family and plays important roles in muscle growth and carcinogenesis. However, the biological function of FHL1 remains largely unknown. Here, we show that FHL1 physically and functionally interacted with oestrogen receptors (ERs), which are involved in breast cancer development and progression. FHL1 bound specifically to the activation function-1 domain of ER. Physical interaction of FHL1 and ER is required for FHL1 repression of oestrogen-responsive gene transcription. FHL1 affected recruitment of ER to an oestrogen-responsive promoter and ER binding to an oestrogen-responsive element. Overexpression of FHL1 in breast cancer cells decreased expression of oestrogen-responsive proteins, whereas knockdown of endogenous FHL1 with FHL1 small interfering RNA increased the expression of these proteins. Further analysis of 46 breast cancer samples showed that FHL1 expression negatively associated with oestrogen-responsive gene expression in breast cancer cells. FHL1 inhibited anchorage-dependent and -independent breast cancer cell growth. These results suggest that FHL1 may play an important role in ER signalling as well as breast cancer cell growth regulation.
Long Cheng - One of the best experts on this subject based on the ideXlab platform.
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FHL1 inhibits the growth of tongue squamous cell carcinoma cells via g1 s cell cycle arrest
Molecular Medicine Reports, 2015Co-Authors: Wei Ren, Lihua Ding, Long Cheng, Panfeng Lian, Xin Guan, Hongyuan Wang, Zhenyang Gao, Xin Huang, Fengjun Xiao, Lisheng WangAbstract:Abstract Four and a half LIM protein 1 (FHL1) has been characterized as a tumor suppressor in various types of tumor. However, the biological function and underlying mechanism of FHL1 in tongue squamous cell carcinoma (TSCC) remain to be elucidated. The present study demonstrated that FHL1 inhibits anchorage‑dependent and ‑independent growth of TSCC cells in vitro and tumor growth in nude mice, as determined by cell proliferation and soft agar assays. Knockdown of FHL1 with FHL1 small interfering RNA (siRNA) promoted tumor growth in nude mice. Mechanistically, flow cytometric analysis showed that knockdown of FHL1 promoted G1/S cell cycle progression. Furthermore, expression of cell cycle‑associated regulators, cyclin D and cyclin E, were detected by western blotting and reverse transcription‑quantitative polymerase chain reaction. Cyclin D and cyclin E were markedly elevated at both the protein and mRNA level in the FHL1 siRNA‑transfected cells. These results suggested that FHL1 has a tumor suppressive role in TSCC and that FHL1 may be a useful target for TSCC gene therapy.
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FHL1 inhibits the growth of tongue squamous cell carcinoma cells via G1/S cell cycle arrest
Molecular medicine reports, 2015Co-Authors: Wei Ren, Lihua Ding, Long Cheng, Panfeng Lian, Xin Guan, Hongyuan Wang, Zhenyang Gao, Xin Huang, Fengjun XiaoAbstract:Abstract Four and a half LIM protein 1 (FHL1) has been characterized as a tumor suppressor in various types of tumor. However, the biological function and underlying mechanism of FHL1 in tongue squamous cell carcinoma (TSCC) remain to be elucidated. The present study demonstrated that FHL1 inhibits anchorage‑dependent and ‑independent growth of TSCC cells in vitro and tumor growth in nude mice, as determined by cell proliferation and soft agar assays. Knockdown of FHL1 with FHL1 small interfering RNA (siRNA) promoted tumor growth in nude mice. Mechanistically, flow cytometric analysis showed that knockdown of FHL1 promoted G1/S cell cycle progression. Furthermore, expression of cell cycle‑associated regulators, cyclin D and cyclin E, were detected by western blotting and reverse transcription‑quantitative polymerase chain reaction. Cyclin D and cyclin E were markedly elevated at both the protein and mRNA level in the FHL1 siRNA‑transfected cells. These results suggested that FHL1 has a tumor suppressive role in TSCC and that FHL1 may be a useful target for TSCC gene therapy.
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MiR-410 is overexpressed in liver and colorectal tumors and enhances tumor cell growth by silencing FHL1 via a direct/indirect mechanism.
PloS one, 2014Co-Authors: Yu Wang, Jing Zhang, Zhongyi Fan, Long Cheng, Mengmeng Jiang, Xiaoai Zhang, Haifeng SongAbstract:FHL1 is an important tumor-suppressor that is downregulated in multiple tumors by unknown mechanisms. We demonstrated that miR-410 specifically targets the 3′UTR of FHL1. Furthermore, using DNA bisulfite modification and sequencing experiments, we demonstrated that the FHL1 promoter is hypermethylated in cancer cells. FHL1 methylation is increased upon miR-410 expression, suggesting that the regulation of FHL1 by miR-410 occurs by a dual mechanism. Using chromatin immunoprecipitation assays, we observed that miR-410 overexpression results in the increased binding of DNMT3A at the FHL1 promoter, which could explain how miR-410 regulates FHL1 methylation. Importantly, in vitro and in vivo results suggest that miR-410 may have oncogenic properties. Furthermore, both miR-410 and DNMT3A are upregulated in clinical human liver and colorectal tumors cancers. Our results suggest that miR-410 may function as an oncomiR and are consistent with its key function in regulating FHL1 in certain digestive system cancers.
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Downregulation and growth inhibitory role of FHL1 in lung cancer
International journal of cancer, 2011Co-Authors: Chang Niu, Lihua Ding, Hao Zhang, Long Cheng, Xi Qin, Chaoyang Liang, Juntang Guo, Qunwei Zhang, Bin YuanAbstract:Four and a half Lin-11, Isl-1, Mac-3 (LIM) protein 1 (FHL1) has been linked to carcinogenesis. However, the role of FHL1 in lung cancer remains unclear and the detailed mechanism underlying its tumor suppressive role is poorly understood. The purpose of this study was to examine FHL1 expression in lung cancer patients and to investigate how it was associated with lung cancer cell growth. Immunoblotting and immunohistochemistry showed that FHL1 protein was downregulated in over 90% of 80 lung cancer patients. FHL1 expression was strongly correlated with tumor histological types (p < 10 24 ) and the differentiation of the tumor (p 5 0.002). FHL1 inhibited anchorage-dependent and -independent growth of human lung cancer cell lines. The inhibitory effects of FHL1 on lung cancer cell growth were associated with both the G1 and the G2/M cell cycle arrest concomitant with a marked inhibition of cyclin A, cyclin B1 and cyclin D as well as the induction of the cyclin dependent kinase inhibitors p21 (WAF1/CIP1) and p27 (Kip1). Direct intratumoral injection of an adenovirus expressing FHL1 dramatically suppressed the growth of A549 lung cancer cells in nude mice. Our data suggest that reduced expression of FHL1 may play an important role in the development and progression of lung cancer and that FHL1 may be a useful target for lung cancer gene therapy.
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Four and a half LIM domains 1 (FHL1) and receptor interacting protein of 140 kDa (RIP140) interact and cooperate in estrogen signaling
The international journal of biochemistry & cell biology, 2009Co-Authors: Jing Lin, Lihua Ding, Rui Jin, Hao Zhang, Long Cheng, Xi Qin, Jiake ChaiAbstract:Abstract Four and a half LIM domains 1 (FHL1) belongs to a family of LIM-only proteins that regulate gene transcription, cell proliferation, differentiation and apoptosis. However, the biological function of FHL1 remains largely unknown. We used a yeast two-hybrid system and identified receptor interacting protein of 140 kDa (RIP140) as a novel FHL1-binding protein. RIP140 interacted with FHL1 both in vitro and in mammalian cells and estrogen enhanced this interaction. All domains of FHL1 are required to interact with RIP140. Overexpression of FHL1 enhanced RIP140 repression of estrogen signaling in breast cancer cells in a reporter assay, whereas reduction of endogenous FHL1 with FHL1 small interfering RNA abolished this effect. Furthermore, overexpression of the FHL1 deletion mutant that lacks the RIP140-binding sites had no effect on RIP140 repression of estrogen signaling. Consistent with the results of the reporter assays, FHL1 and RIP140 synergistically inhibited the transcription of the estrogen-responsive gene pS2. The results presented here suggested the cooperative transcriptional regulation of estrogen signaling by FHL1 and RIP140, and might provide a new regulation mechanism by which estrogen signaling-related diseases such as breast cancer develop.
Julien Burlaud-gaillard - One of the best experts on this subject based on the ideXlab platform.
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FHL1 is a major host factor for chikungunya virus infection
Nature, 2019Co-Authors: Laurent Meertens, Mohamed Lamine Hafirassou, Lucie Bonnet-madin, Vasiliya Kril, Beate M. Kümmerer, Athena Labeau, Alexis Brugier, Etienne Simon-loriere, Thérèse Couderc, Julien Burlaud-gaillardAbstract:Chikungunya virus (CHIKV) is a re-emerging alphavirus that is transmitted to humans by mosquito bites and causes musculoskeletal and joint pain^ 1 , 2 . Despite intensive investigations, the human cellular factors that are critical for CHIKV infection remain unknown, hampering the understanding of viral pathogenesis and the development of anti-CHIKV therapies. Here we identified the four-and-a-half LIM domain protein 1 (FHL1)^ 3 as a host factor that is required for CHIKV permissiveness and pathogenesis in humans and mice. Ablation of FHL1 expression results in the inhibition of infection by several CHIKV strains and o’nyong-nyong virus, but not by other alphaviruses and flaviviruses. Conversely, expression of FHL1 promotes CHIKV infection in cells that do not normally express it. FHL1 interacts directly with the hypervariable domain of the nsP3 protein of CHIKV and is essential for the replication of viral RNA. FHL1 is highly expressed in CHIKV-target cells and is particularly abundant in muscles^ 3 , 4 . Dermal fibroblasts and muscle cells derived from patients with Emery–Dreifuss muscular dystrophy that lack functional FHL1^ 5 are resistant to CHIKV infection. Furthermore, CHIKV infection is undetectable in FHL1-knockout mice. Overall, this study shows that FHL1 is a key factor expressed by the host that enables CHIKV infection and identifies the interaction between nsP3 and FHL1 as a promising target for the development of anti-CHIKV therapies. FHL1 is a key factor expressed by humans and mice that is required for chikungunya virus infection and is therefore a promising target for the development of therapies against chikungunya virus.
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FHL1 is a major host factor for chikungunya virus infection
Nature, 2019Co-Authors: Laurent Meertens, Mohamed Lamine Hafirassou, Lucie Bonnet-madin, Vasiliya Kril, Beate M. Kümmerer, Athena Labeau, Alexis Brugier, Etienne Simon-loriere, Thérèse Couderc, Julien Burlaud-gaillardAbstract:Chikungunya virus (CHIKV) is a re-emerging alphavirus that is transmitted to humans by mosquito bites and causes musculoskeletal and joint pain1,2. Despite intensive investigations, the human cellular factors that are critical for CHIKV infection remain unknown, hampering the understanding of viral pathogenesis and the development of anti-CHIKV therapies. Here we identified the four-and-a-half LIM domain protein 1 (FHL1)3 as a host factor that is required for CHIKV permissiveness and pathogenesis in humans and mice. Ablation of FHL1 expression results in the inhibition of infection by several CHIKV strains and o'nyong-nyong virus, but not by other alphaviruses and flaviviruses. Conversely, expression of FHL1 promotes CHIKV infection in cells that do not normally express it. FHL1 interacts directly with the hypervariable domain of the nsP3 protein of CHIKV and is essential for the replication of viral RNA. FHL1 is highly expressed in CHIKV-target cells and is particularly abundant in muscles3,4. Dermal fibroblasts and muscle cells derived from patients with Emery-Dreifuss muscular dystrophy that lack functional FHL15 are resistant to CHIKV infection. Furthermore, CHIKV infection is undetectable in FHL1-knockout mice. Overall, this study shows that FHL1 is a key factor expressed by the host that enables CHIKV infection and identifies the interaction between nsP3 and FHL1 as a promising target for the development of anti-CHIKV therapies.
Meagan Jane Mcgrath - One of the best experts on this subject based on the ideXlab platform.
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FHL1 reduces dystrophy in transgenic mice overexpressing FSHD muscular dystrophy region gene 1 (FRG1).
PloS one, 2015Co-Authors: Sandra J Feeney, Meagan Jane Mcgrath, Absorn Sriratana, Rossella Tupler, John T Price, Catriona Mclean, Stefan M. Gehrig, Gordon S. Lynch, Colleen Elizabeth D'arcy, Christina Anne MitchellAbstract:Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal-dominant disease with no effective treatment. The genetic cause of FSHD is complex and the primary pathogenic insult underlying the muscle disease is unknown. Several disease candidate genes have been proposed including DUX4 and FRG1. Expression analysis studies of FSHD report the deregulation of genes which mediate myoblast differentiation and fusion. Transgenic mice overexpressing FRG1 recapitulate the FSHD muscular dystrophy phenotype. Our current study selectively examines how increased expression of FRG1 may contribute to myoblast differentiation defects. We generated stable C2C12 cell lines overexpressing FRG1, which exhibited a myoblast fusion defect upon differentiation. To determine if myoblast fusion defects contribute to the FRG1 mouse dystrophic phenotype, this strain was crossed with skeletal muscle specific FHL1-transgenic mice. We previously reported that FHL1 promotes myoblast fusion in vitro and FHL1-transgenic mice develop skeletal muscle hypertrophy. In the current study, FRG1 mice overexpressing FHL1 showed an improvement in the dystrophic phenotype, including a reduced spinal kyphosis, increased muscle mass and myofiber size, and decreased muscle fibrosis. FHL1 expression in FRG1 mice, did not alter satellite cell number or activation, but enhanced myoblast fusion. Primary myoblasts isolated from FRG1 mice showed a myoblast fusion defect that was rescued by FHL1 expression. Therefore, increased FRG1 expression may contribute to a muscular dystrophy phenotype resembling FSHD by impairing myoblast fusion, a defect that can be rescued by enhanced myoblast fusion via expression of FHL1.
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FHL1 mutants that cause clinically distinct human myopathies form protein aggregates and impair myoblast differentiation
Journal of Cell Science, 2014Co-Authors: Brendan R Wilding, Meagan Jane Mcgrath, Gisèle Bonne, Christina Anne MitchellAbstract:ABSTRACT FHL1 mutations cause several clinically heterogeneous myopathies, including reducing body myopathy (RBM), scapuloperoneal myopathy (SPM) and X-linked myopathy with postural muscle atrophy (XMPMA). The molecular mechanisms underlying the pathogenesis of FHL1 myopathies are unknown. Protein aggregates, designated ‘reducing bodies’, that contain mutant FHL1 are detected in RBM muscle but not in several other FHL1 myopathies. Here, RBM, SPM and XMPMA FHL1 mutants were expressed in C2C12 cells and showed equivalent protein expression to wild-type FHL1. These mutants formed aggregates that were positive for the reducing body stain Menadione-NBT, analogous to RBM muscle aggregates. However, hypertrophic cardiomyopathy (HCM) and Emery-Dreifuss muscular dystrophy (EDMD) FHL1 mutants generally exhibited reduced expression. Wild-type FHL1 promotes myoblast differentiation; however, RBM, SPM and XMPMA mutations impaired differentiation, consistent with a loss of normal FHL1 function. Furthermore, SPM and XMPMA FHL1 mutants retarded myotube formation relative to vector control, consistent with a dominant-negative or toxic function. Mutant FHL1 myotube formation was partially rescued by expression of a constitutively active FHL1-binding partner, NFATc1. This is the first study to show that FHL1 mutations identified in several clinically distinct myopathies lead to similar protein aggregation and impair myotube formation, suggesting a common pathogenic mechanism despite heterogeneous clinical features.
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Identification of FHL1 as a therapeutic target for Duchenne muscular dystrophy
Human molecular genetics, 2013Co-Authors: Colleen Elizabeth D'arcy, Christina Anne Mitchell, Sandra J Feeney, Catriona Mclean, Stefan M. Gehrig, Gordon S. Lynch, Belinda S Cowling, Jaclyn Elizabeth Smith, Meagan Jane McgrathAbstract:Utrophin is a potential therapeutic target for the fatal muscle disease, Duchenne muscular dystrophy (DMD). In adult skeletal muscle, utrophin is restricted to the neuromuscular and myotendinous junctions and can compensate for dystrophin loss in mdx mice, a mouse model of DMD, but requires sarcolemmal localization. NFATc1-mediated transcription regulates utrophin expression and the LIM protein, FHL1 which promotes muscle hypertrophy, is a transcriptional activator of NFATc1. By generating mdx/FHL1-transgenic mice, we demonstrate that FHL1 potentiates NFATc1 activation of utrophin to ameliorate the dystrophic pathology. Transgenic FHL1 expression increased sarcolemmal membrane stability, reduced muscle degeneration, decreased inflammation and conferred protection from contraction-induced injury in mdx mice. Significantly, FHL1 expression also reduced progressive muscle degeneration and fibrosis in the diaphragm of aged mdx mice. FHL1 enhanced NFATc1 activation of the utrophin promoter and increased sarcolemmal expression of utrophin in muscles of mdx mice, directing the assembly of a substitute utrophin-glycoprotein complex, and revealing a novel FHL1-NFATc1-utrophin signaling axis that can functionally compensate for dystrophin.
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t p 35 FHL1 is beneficial in reducing muscle wasting in dystrophic frg1 mice
Neuromuscular Disorders, 2012Co-Authors: Sandra J Feeney, Meagan Jane Mcgrath, Colleen Elizabeth Darcy, Absorn Sriratana, Rossella Tupler, John T Price, Catriona Mclean, Christina Anne MitchellAbstract:Abstract Four and a half LIM 1 (FHL1) is a protein highly expressed in skeletal muscle, and we have previously reported that FHL1 can promote myoblast fusion in vitro and skeletal muscle hypertrophy in vivo by activating the calcineurin/NFATc1 pathway. Therefore FHL1 has potential as a therapeutic target for muscle diseases that display a myoblast fusion defect and/or progressive muscle wasting. The focus of this study was to determine if FHL1 can reduce muscle wasting in the dystrophic FRG1 mouse. FRG1 is one of several candidate genes for Facioscapulohumeral muscular dystrophy and FRG1 transgenic mice show resemblance to this disease clinically and pathologically. The dystrophy in FRG1 mice is characterised by progressive muscle wasting and is accompanied by spinal kyphosis caused by weakness of the trapezius muscle. We generated myoblast cell lines overexpressing FRG1 that exhibited a myoblast fusion defect, and as FHL1 enhances myoblast fusion we generated FRG1 mice over-expressing FHL1 by crossing our FHL1 skeletal muscle-specific transgenic mice with the dystrophic FRG1 mouse model. X-ray images of 6-week old mice revealed that FHL1 reduced the kyphosis of FRG1 mice. Analysis of muscle weights in mice revealed an increased muscle mass in FRG1/FHL1 mice relative to FRG1 mice, indicating FHL1 reduces muscle wasting. Histological analysis of muscle further revealed an increase in the average myofibre cross-sectional area and increase in the proportion of larger myofibres in FRG1/FHL1 mice compared to FRG1 mice. This beneficial effect of FHL1 was present in 6-week old FRG1/FHL1 mice and sustained into adulthood (12-weeks). FRG1/FHL1 mice also exhibited a reduction in fibrosis and fat accumulation in muscle further supporting the sustained benefit of FHL1 in reducing the dystrophic pathology of FRG1 mice. This study confirms that FHL1 is sufficient to reduce the dystrophy in FRG1 mice and is a potential future therapeutic target in treating muscle diseases.
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T.P.34 FHL1 reduces muscle degeneration in dystrophin-deficient mdx mice through the sarcolemmal recruitment of utrophin
Neuromuscular Disorders, 2012Co-Authors: Colleen Elizabeth D'arcy, Christina Anne Mitchell, Sandra J Feeney, Catriona Mclean, Stefan M. Gehrig, Gordon S. Lynch, Belinda S Cowling, Meagan Jane McgrathAbstract:Abstract Duchenne muscular dystrophy (DMD) is caused by dystrophin gene mutations, resulting in loss of dystrophin from the sarcolemma. Utrophin is a therapeutic target for DMD due to its functional compensation for dystrophin, by forming the protective utrophin–glycoprotein complex (UGC) at the sarcolemma. In adult muscle fibres utrophin localizes to the neuromuscular junction, therefore the challenge is to identify factors which increase utrophin expression and sarcolemmal recruitment. Calcineurin/NFATc1 is a utrophin regulatory pathway and we reported that FHL1 coactivates NFATc1. We crossed our skeletal muscle FHL1 transgenic mice with the mdx model of DMD. FHL1 ameliorated degeneration in multiple mdx muscles at 4- and 16-weeks of age. Relative to mdx mice, mdx /FHL1 mice also exhibited decreased serum creatine kinase (2.5-fold) and a reduction in muscle fibres stained for serum IgM, further indicating the protective effect of FHL1. Chronic myofibre damage in DMD and mdx mice induces pronounced muscle infiltration with macrophages, which were reduced in mdx /FHL1 mice. The benefit of FHL1 was sustained in older mdx /FHL1 mice (9months) as shown by a significant reduction (2-fold) in diaphragm fibrosis compared to mdx mice. In functional studies the tibialis anterior from mdx /FHL1 mice was also protected against contraction-induced injury, indicating FHL1 stabilizes muscle fibres during repetitive muscle contractions. We identified the mechanism by which FHL1 reduced muscle degeneration; luciferase assays revealed FHL1 potentiated NFATc1-activation of the utrophin A promoter and utrophin mRNA and protein were increased in mdx /FHL1 mice. Immunofluorescence analysis revealed utrophin localized to the sarcolemma in adult muscle fibres of mdx /FHL1 mice, where it directed formation of the UGC by recruiting α- and β-dystroglycan, α- and γ-sarcoglycan and syntrophin. This study identifies FHL1 as a utrophin regulatory protein and therefore a potential therapeutic target for DMD.
Christina Anne Mitchell - One of the best experts on this subject based on the ideXlab platform.
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FHL1 reduces dystrophy in transgenic mice overexpressing FSHD muscular dystrophy region gene 1 (FRG1).
PloS one, 2015Co-Authors: Sandra J Feeney, Meagan Jane Mcgrath, Absorn Sriratana, Rossella Tupler, John T Price, Catriona Mclean, Stefan M. Gehrig, Gordon S. Lynch, Colleen Elizabeth D'arcy, Christina Anne MitchellAbstract:Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal-dominant disease with no effective treatment. The genetic cause of FSHD is complex and the primary pathogenic insult underlying the muscle disease is unknown. Several disease candidate genes have been proposed including DUX4 and FRG1. Expression analysis studies of FSHD report the deregulation of genes which mediate myoblast differentiation and fusion. Transgenic mice overexpressing FRG1 recapitulate the FSHD muscular dystrophy phenotype. Our current study selectively examines how increased expression of FRG1 may contribute to myoblast differentiation defects. We generated stable C2C12 cell lines overexpressing FRG1, which exhibited a myoblast fusion defect upon differentiation. To determine if myoblast fusion defects contribute to the FRG1 mouse dystrophic phenotype, this strain was crossed with skeletal muscle specific FHL1-transgenic mice. We previously reported that FHL1 promotes myoblast fusion in vitro and FHL1-transgenic mice develop skeletal muscle hypertrophy. In the current study, FRG1 mice overexpressing FHL1 showed an improvement in the dystrophic phenotype, including a reduced spinal kyphosis, increased muscle mass and myofiber size, and decreased muscle fibrosis. FHL1 expression in FRG1 mice, did not alter satellite cell number or activation, but enhanced myoblast fusion. Primary myoblasts isolated from FRG1 mice showed a myoblast fusion defect that was rescued by FHL1 expression. Therefore, increased FRG1 expression may contribute to a muscular dystrophy phenotype resembling FSHD by impairing myoblast fusion, a defect that can be rescued by enhanced myoblast fusion via expression of FHL1.
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FHL1 mutants that cause clinically distinct human myopathies form protein aggregates and impair myoblast differentiation
Journal of Cell Science, 2014Co-Authors: Brendan R Wilding, Meagan Jane Mcgrath, Gisèle Bonne, Christina Anne MitchellAbstract:ABSTRACT FHL1 mutations cause several clinically heterogeneous myopathies, including reducing body myopathy (RBM), scapuloperoneal myopathy (SPM) and X-linked myopathy with postural muscle atrophy (XMPMA). The molecular mechanisms underlying the pathogenesis of FHL1 myopathies are unknown. Protein aggregates, designated ‘reducing bodies’, that contain mutant FHL1 are detected in RBM muscle but not in several other FHL1 myopathies. Here, RBM, SPM and XMPMA FHL1 mutants were expressed in C2C12 cells and showed equivalent protein expression to wild-type FHL1. These mutants formed aggregates that were positive for the reducing body stain Menadione-NBT, analogous to RBM muscle aggregates. However, hypertrophic cardiomyopathy (HCM) and Emery-Dreifuss muscular dystrophy (EDMD) FHL1 mutants generally exhibited reduced expression. Wild-type FHL1 promotes myoblast differentiation; however, RBM, SPM and XMPMA mutations impaired differentiation, consistent with a loss of normal FHL1 function. Furthermore, SPM and XMPMA FHL1 mutants retarded myotube formation relative to vector control, consistent with a dominant-negative or toxic function. Mutant FHL1 myotube formation was partially rescued by expression of a constitutively active FHL1-binding partner, NFATc1. This is the first study to show that FHL1 mutations identified in several clinically distinct myopathies lead to similar protein aggregation and impair myotube formation, suggesting a common pathogenic mechanism despite heterogeneous clinical features.
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Identification of FHL1 as a therapeutic target for Duchenne muscular dystrophy
Human molecular genetics, 2013Co-Authors: Colleen Elizabeth D'arcy, Christina Anne Mitchell, Sandra J Feeney, Catriona Mclean, Stefan M. Gehrig, Gordon S. Lynch, Belinda S Cowling, Jaclyn Elizabeth Smith, Meagan Jane McgrathAbstract:Utrophin is a potential therapeutic target for the fatal muscle disease, Duchenne muscular dystrophy (DMD). In adult skeletal muscle, utrophin is restricted to the neuromuscular and myotendinous junctions and can compensate for dystrophin loss in mdx mice, a mouse model of DMD, but requires sarcolemmal localization. NFATc1-mediated transcription regulates utrophin expression and the LIM protein, FHL1 which promotes muscle hypertrophy, is a transcriptional activator of NFATc1. By generating mdx/FHL1-transgenic mice, we demonstrate that FHL1 potentiates NFATc1 activation of utrophin to ameliorate the dystrophic pathology. Transgenic FHL1 expression increased sarcolemmal membrane stability, reduced muscle degeneration, decreased inflammation and conferred protection from contraction-induced injury in mdx mice. Significantly, FHL1 expression also reduced progressive muscle degeneration and fibrosis in the diaphragm of aged mdx mice. FHL1 enhanced NFATc1 activation of the utrophin promoter and increased sarcolemmal expression of utrophin in muscles of mdx mice, directing the assembly of a substitute utrophin-glycoprotein complex, and revealing a novel FHL1-NFATc1-utrophin signaling axis that can functionally compensate for dystrophin.
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t p 35 FHL1 is beneficial in reducing muscle wasting in dystrophic frg1 mice
Neuromuscular Disorders, 2012Co-Authors: Sandra J Feeney, Meagan Jane Mcgrath, Colleen Elizabeth Darcy, Absorn Sriratana, Rossella Tupler, John T Price, Catriona Mclean, Christina Anne MitchellAbstract:Abstract Four and a half LIM 1 (FHL1) is a protein highly expressed in skeletal muscle, and we have previously reported that FHL1 can promote myoblast fusion in vitro and skeletal muscle hypertrophy in vivo by activating the calcineurin/NFATc1 pathway. Therefore FHL1 has potential as a therapeutic target for muscle diseases that display a myoblast fusion defect and/or progressive muscle wasting. The focus of this study was to determine if FHL1 can reduce muscle wasting in the dystrophic FRG1 mouse. FRG1 is one of several candidate genes for Facioscapulohumeral muscular dystrophy and FRG1 transgenic mice show resemblance to this disease clinically and pathologically. The dystrophy in FRG1 mice is characterised by progressive muscle wasting and is accompanied by spinal kyphosis caused by weakness of the trapezius muscle. We generated myoblast cell lines overexpressing FRG1 that exhibited a myoblast fusion defect, and as FHL1 enhances myoblast fusion we generated FRG1 mice over-expressing FHL1 by crossing our FHL1 skeletal muscle-specific transgenic mice with the dystrophic FRG1 mouse model. X-ray images of 6-week old mice revealed that FHL1 reduced the kyphosis of FRG1 mice. Analysis of muscle weights in mice revealed an increased muscle mass in FRG1/FHL1 mice relative to FRG1 mice, indicating FHL1 reduces muscle wasting. Histological analysis of muscle further revealed an increase in the average myofibre cross-sectional area and increase in the proportion of larger myofibres in FRG1/FHL1 mice compared to FRG1 mice. This beneficial effect of FHL1 was present in 6-week old FRG1/FHL1 mice and sustained into adulthood (12-weeks). FRG1/FHL1 mice also exhibited a reduction in fibrosis and fat accumulation in muscle further supporting the sustained benefit of FHL1 in reducing the dystrophic pathology of FRG1 mice. This study confirms that FHL1 is sufficient to reduce the dystrophy in FRG1 mice and is a potential future therapeutic target in treating muscle diseases.
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T.P.34 FHL1 reduces muscle degeneration in dystrophin-deficient mdx mice through the sarcolemmal recruitment of utrophin
Neuromuscular Disorders, 2012Co-Authors: Colleen Elizabeth D'arcy, Christina Anne Mitchell, Sandra J Feeney, Catriona Mclean, Stefan M. Gehrig, Gordon S. Lynch, Belinda S Cowling, Meagan Jane McgrathAbstract:Abstract Duchenne muscular dystrophy (DMD) is caused by dystrophin gene mutations, resulting in loss of dystrophin from the sarcolemma. Utrophin is a therapeutic target for DMD due to its functional compensation for dystrophin, by forming the protective utrophin–glycoprotein complex (UGC) at the sarcolemma. In adult muscle fibres utrophin localizes to the neuromuscular junction, therefore the challenge is to identify factors which increase utrophin expression and sarcolemmal recruitment. Calcineurin/NFATc1 is a utrophin regulatory pathway and we reported that FHL1 coactivates NFATc1. We crossed our skeletal muscle FHL1 transgenic mice with the mdx model of DMD. FHL1 ameliorated degeneration in multiple mdx muscles at 4- and 16-weeks of age. Relative to mdx mice, mdx /FHL1 mice also exhibited decreased serum creatine kinase (2.5-fold) and a reduction in muscle fibres stained for serum IgM, further indicating the protective effect of FHL1. Chronic myofibre damage in DMD and mdx mice induces pronounced muscle infiltration with macrophages, which were reduced in mdx /FHL1 mice. The benefit of FHL1 was sustained in older mdx /FHL1 mice (9months) as shown by a significant reduction (2-fold) in diaphragm fibrosis compared to mdx mice. In functional studies the tibialis anterior from mdx /FHL1 mice was also protected against contraction-induced injury, indicating FHL1 stabilizes muscle fibres during repetitive muscle contractions. We identified the mechanism by which FHL1 reduced muscle degeneration; luciferase assays revealed FHL1 potentiated NFATc1-activation of the utrophin A promoter and utrophin mRNA and protein were increased in mdx /FHL1 mice. Immunofluorescence analysis revealed utrophin localized to the sarcolemma in adult muscle fibres of mdx /FHL1 mice, where it directed formation of the UGC by recruiting α- and β-dystroglycan, α- and γ-sarcoglycan and syntrophin. This study identifies FHL1 as a utrophin regulatory protein and therefore a potential therapeutic target for DMD.