Half LIM Domain Protein Research Articles

Role of four and a half LIM domain protein 1 in tumors (Review).

As a cytoskeletal protein, the four and a half LIM domain protein 1 (FHL1) is widely expressed in various cells, particularly skeletal and cardiac muscle cells. FHL1 is involved in the development of the skeletal muscle and myocardium, regulations of gene transcription and thyroid function, and other physiological processes. Its expression is closely related to numerous diseases, such as skeletal muscle disease and viral infections. With the advances in research, the role of FHL1 in the development of tumors is also being revealed. The mechanism of FHL1 in the regulation of tumor growth is complex and is becoming a research focus. It is also expected to become a potential target for tumor therapy. Therefore, the present article reviewed the progress in research on the role of FHL1 in cancer.

MiR-3682-3p promotes esophageal cancer progression by targeting FHL1 and activating the Wnt/β-catenin signaling pathway

BackgroundEsophageal cancer (EC) is highly ranked among all cancers in terms of its incidence and mortality rates. MicroRNAs (miRNAs) are considered to play key regulatory parts in EC. Multiple research studies have indicated the involvement of miR-3682-3p and four and a half LIM domain protein 1 (FHL1) in the achievement of tumors. The aim of this research was to clarify the significance of these genes and their possible molecular mechanism in EC. MethodsData from a database and the tissue microarray were made to analyze the expression and clinical significance of miR-3682-3p or FHL1 in EC. Reverse transcription quantitative PCR and Western blotting were used to detect the expression levels of miR-3682-3p and FHL1 in EC cells. CCK8, EdU, wound healing, Transwell, flow cytometry, and Western blotting assays were performed to ascertain the biological roles of miR-3682-3p and FHL1 in EC cells. To confirm the impact of miR-3682-3p in vivo, a subcutaneous tumor model was created in nude mice. The direct interaction between miR-3682-3p and FHL1 was demonstrated through a luciferase assay, and the western blotting technique was employed to assess the levels of crucial proteins within the Wnt/β-catenin pathway. ResultsThe noticeable increase in the expression of miR-3682-3p and the decrease in the expression of FHL1 were observed, which correlated with a negative impact on the patients' overall survival. Upregulation of miR-3682-3p expression promoted the growth and metastasis of EC, while overexpression of FHL1 partially reversed these effects. Finally, miR-3682-3p motivates the Wnt/β-catenin signal transduction by directly targeting FHL1. ConclusionMiR-3682-3p along the FHL1 axis activated the Wnt/β-catenin signaling pathway and thus promoted EC malignancy.

Derivation of two human induced pluripotent stem cell lines carrying a missense mutation in FHL1 (c.377G > A, p.C126Y) linked to familial muscular dystrophy

FHL1 gene locates in the Xq26 region and encodes for four and half LIM domain protein 1. It plays a crucial role in muscle cells and mutations in FHL1 are related to muscular dystrophy (MD). Peripheral blood mononuclear cells (PBMCs) were obtained from 2 family patients with MD that carry a pathogenic missense mutation in FHL1 (c.377G > A, p.C126Y). Induced pluripotent stem cells (iPSCs) were generated by PBMCs reprogramming using the lentiviral-hSTEMCCA-loxP vector, obtaining FHL1-T and FHL1-V iPSCs lines from patients. FHL1 genotype was maintained, and stemness and pluripotency were confirmed in both iPSCs lines.

Carnosol attenuated atrophy of C2C12 myotubes induced by tumour-derived exosomal miR-183-5p through inhibiting Smad3 pathway activation and keeping mitochondrial respiration.

Cancer-derived exosomes are involved in the development of cancer cachexia. Carnosol, which exhibited ameliorating effects on cancer cachexia of C26 tumour-bearing mice in our previous study, alleviated atrophy of C2C12 myotubes induced by exosomes of C26 tumour cells in the present study. MiR-183-5p was found to be rich in C26 cells and C26 exosomes, and miR-183-5p mimic could directly induce atrophy of C2C12 myotubes. Carnosol at 5 to 20 μM could dose-dependently ameliorate the myotube atrophy induced by miR-183-5p. Four and a half LIM domain protein 1 (FHL1) was shown to be the direct target of miR-183-5p. Increase in myostatin, p-Smad3, MuRF-1, Atrogin-1, HIF-1α and p-STAT3 and decrease in mitochondrial respiration were also induced by miR-183-5p mimic in C2C12 myotubes. Carnosol could not affect the decrease in FHL-1 and the activation of STAT3 pathway but could significantly alleviate the increase in myostatin, p-Smad3, MuRF-1, Atrogin-1 and the decrease in mitochondrial respiration induced by miR-183-5p. The protective effects of carnosol on myotubes against atrophy of C2C12 myotubes induced by miR-183-5p, based on both its inhibiting effects on MuRF-1 and Atrogin-1-mediated protein degradation and its ability of keeping the mitochondrial respiration, might contribute to its ameliorating effects on cancer cachexia.

The Roles of FHL3 in Cancer.

The four and a half LIM domain protein 3, also named the LIM-protein FHL3, belongs to the LIM-only family. Based on the special structure of LIM-only proteins, FHL3 can perform significant functions in muscle proliferation and cardiovascular diseases by regulating cell growth and signal transduction. In recent years, there has been increasing evidence of a relation between FHLs and tumor biology, since FHL3 is often overexpressed or downregulated in different cancers. On the one hand, FHL3 can function as a tumor suppressor and influence the expression of downstream genes. On the other hand, FHL3 can also play a role as an oncoprotein in some cancers to promote tumor progression via phosphorylation. Thus, FHL3 is proposed to have a dual effect on cancer progression, reflecting its complex roles in cancer. This review focuses on the roles of FHL3 in cancer progression and discusses the interaction of FHL3 with other proteins and transcription factors. Finally, the clinical significance of FHL3 for the treatment of cancers is discussed.

Stiffness is associated with hepatic stellate cell heterogeneity during liver fibrosis.

The fibrogenic wound-healing response in liver increases stiffness. Stiffness mechanotransduction, in turn, amplifies fibrogenesis. Here, we aimed to understand the distribution of stiffness in fibrotic liver, how it impacts hepatic stellate cell (HSC) heterogeneity, and identify mechanisms by which stiffness amplifies fibrogenic responses. Magnetic resonance elastography and atomic force microscopy demonstrated a heterogeneous distribution of liver stiffness at macroscopic and microscopic levels, respectively, in a carbon tetrachloride (CCl4) mouse model of liver fibrosis as compared with controls. High stiffness was mainly attributed to extracellular matrix dense areas. To identify a stiffness-sensitive HSC subpopulation, we performed single-cell RNA sequencing (scRNA-seq) on primary HSCs derived from healthy versus CCl4-treated mice. A subcluster of HSCs was matrix-associated with the most upregulated pathway in this subpopulation being focal adhesion signaling, including a specific protein termed four and a half LIM domains protein 2 (FHL2). In vitro, FHL2 expression was increased in primary human HSCs cultured on stiff matrix as compared with HSCs on soft matrix. Moreover, FHL2 knockdown inhibited fibronectin and collagen 1 expression, whereas its overexpression promoted matrix production. In summary, we demonstrate stiffness heterogeneity at the whole organ, lobular, and cellular level, which drives an amplification loop of fibrogenesis through specific focal adhesion molecular pathways.NEW & NOTEWORTHY The fibrogenic wound-healing response in liver increases stiffness. Here, macro and microheterogeneity of liver stiffness correlate with HSC heterogeneity in a hepatic fibrosis mouse model. Fibrogenic HSCs localized in stiff collagen-high areas upregulate the expression of focal adhesion molecule FHL2, which, in turn, promotes extracellular matrix protein expression. These results demonstrate that stiffness heterogeneity at the whole organ, lobular, and cellular level drives an amplification loop of fibrogenesis through specific focal adhesion molecular pathways.

Four and a Half LIM Domains Protein 2 Mediates Bortezomib-Induced Osteogenic Differentiation of Mesenchymal Stem Cells in Multiple Myeloma Through p53 Signaling and β-Catenin Nuclear Enrichment.

Myeloma bone disease (MBD), caused by the inhibition of osteoblast activity and the activation of osteoclast in the bone marrow environment, is the most frequent and life-threatening complication in multiple myeloma (MM) patients. Bortezomib (Bzb) was shown to promote MM-derived mesenchymal stem cells (MM-MSCs) differentiation to osteoblast in vitro and in animal models, promoting the bone formation and regeneration, may be mediated via β-catenin/T-cell factor (TCF) pathway. Further defining molecular mechanism of Bzb-enhanced bone formation in MM will be beneficial for the treatment of myeloma patients. The present study has identified for the first time four and a half LIM domains protein 2 (FHL2), a tissue-specific coregulator that interacts with many osteogenic marker molecules, as a therapeutic target to ameliorate MM bone disease. First, increased messenger RNA (mRNA) and protein levels of FHL2, and the mRNA level of main osteoblast markers (including Runx2, ALP, and Col1A1), were found in MM-patients-derived MSCs after Bzb treatment. FHL2 KD with short hairpin RNA (shRNA) reduced the expression of osteoblast marker genes and blocked the osteogenic differentiation of MM-MSCs regardless of the presence or absence of Bzb, implying that FHL2 is an important activator of the osteogenic differentiation of human MSCs under a proteasome inhibition condition. Molecular analysis showed that the enhanced expression of FHL2 was associated with the Bzb-induced upregulation of p53. No significant change at protein level of total β-catenin was observed with or without Bzb treatment. However, it was mostly enriched to nuclei in MSCs after Bzb treatment. Moreover, β-catenin was restricted to the perinuclear region in FHL2 KD cells. These data provide evidence that FHL2 is essential for promoting β-catenin nuclear enrichment in MM-MSCs. In conclusion, FHL2 is critical for Bzb-induced osteoblast differentiation of MM-MSCs and promotes the osteogenesis, through p53 signaling and β-catenin activation. Targeting FHL2 in MM may provide a new therapeutic strategy for treating MBD.

FHL2 anchors mitochondria to actin and adapts mitochondrial dynamics to glucose supply.

Mitochondrial movement and distribution are fundamental to their function. Here we report a mechanism that regulates mitochondrial movement by anchoring mitochondria to the F-actin cytoskeleton. This mechanism is activated by an increase in glucose influx and the consequent O-GlcNAcylation of TRAK (Milton), a component of the mitochondrial motor-adaptor complex. The protein four and a half LIM domains protein 2 (FHL2) serves as the anchor. FHL2 associates with O-GlcNAcylated TRAK and is both necessary and sufficient to drive the accumulation of F-actin around mitochondria and to arrest mitochondrial movement by anchoring to F-actin. Disruption of F-actin restores mitochondrial movement that had been arrested by either TRAK O-GlcNAcylation or forced direction of FHL2 to mitochondria. This pathway for mitochondrial immobilization is present in both neurons and non-neuronal cells and can thereby adapt mitochondrial dynamics to changes in glucose availability.

Effect of the regulator of G-protein signaling 2 on the proliferation and invasion of oral squamous cell carcinoma cells and its molecular mechanism.

This study aims to investigate the effect of the regulator of G-protein signaling 2 (RGS2) on the proliferation and invasion of oral squamous cell carcinoma (OSCC) cells and its potential molecular mechanism. Metho⁃ds The expression status and clinical significance of RGS2 in head and neck squamous cell carcinomas and matched adjacent normal tissues were evaluated using TCGA database. Three OSCC cell lines (i.e., SCC-9, Cal27, and Fadu) were overexpressed with RGS2, and the effect of RGS2 on cell proliferation and invasion was determined using the Transwell, clone formation, and cell counting kit (CCK)-8 assays. Moreover, the yeast two-hybrid scree-ning and co-immunoprecipitation (Co-IP) assays were conducted to detect the correlation of RGS2, four and a half LIM domains protein 1 (FHL1), and damage DNA-binding protein 1 (DDB1). The expression level of RGS2 in OSCC was significantly lower than that in matched adjacent normal tissues (P=0.023). The high RGS2 expression level was negatively correlated with lymphovascular invasion (P<0.001). After transfection with lentiv-RGS2, the expression of RGS2 was increased, and the invasion and proliferation abilities of OSCC cell lines were evidently inhibited. FHL1 could competitively bind with RGS2, which decreased the integration of DDB1 and RGS2, inhibited the ubiquitination process of RGS2, and maintained the stability of the RGS2 protein. RGS2 plays an important role in the inhibition of OSCC proliferation and invasion. The structure stability of RGS2 is competitively regulated by FHL1 and DDB1.

Maternal smoking during pregnancy aggravated muscle phenotype in FHL1−/y offspring mice similar to congenital clubfoot through P2RX7-mediated pyroptosis

Congenital clubfoot (CCF) is a common birth defect. Maternal smoking during pregnancy increases the risk of CCF. In previous research, we found muscle phenotypes similar to CCF in four and a half LIM domain protein 1 (FHLI) offspring mice (FHL1−/y). However, the role of P2RX7-mediated pyroptosis in the effect of cigarette smoke (CS) on the skeletal muscle of FHL1−/y mice during pregnancy is unclear. In the present study, pregnant mice at 11 days of gestation were exposed to CS and male offspring of wild-type (WT) and FHL1−/y mice were divided into four groups (Control-WT, Control-KO, CS-WT, CS-KO). The histomorphology of lower limb muscles was examined using hematoxylin and eosin (H&E) staining. P2RX7, indicators of pyroptosis (NLRP3, ASC, cleaved-caspase 1, IL-1β), and cytoskeletal proteins (MYBPC2, LDB3) were also detected using immunoblotting. CS exposure during pregnancy aggravated the muscle phenotype similar to CCF in FHL1−/y offspring mice. FHL1 gene knockout (KO) or CS exposure during pregnancy each activated the expression of P2RX7, cell pyroptosis-related proteins (NLRP3, ASC, cleaved-caspase 1, IL-1β), a muscle injury marker (MYOD1), and cytoskeletal proteins (MYBPC2, LDB3); these two factors had an additive effect. The results showed maternal smoking during pregnancy aggravated muscle phenotype similar to CCF in FHL1−/y offspring mice through P2RX7-mediated pyroptosis.

Screening and identification of a novel FHL2 mutation by whole exome sequencing in twins with familial Waldenström macroglobulinemia.

Waldenström macroglobulinemia (WM) is a rare chronic B-cell lymphoma. Familial clustering of WM has been observed over the years. However, little is known about the contribution of inherited genetic variants to familial WM cases. The authors performed whole exome sequencing (WES) of germline DNA samples from twins, one diagnosed with WM and the other diagnosed with immunoglobulin M monoclonal gammopathy of undetermined significance, and their healthy siblings. Bioinformatics analysis of public biological databases was used to identify the most relevant familial WM candidate from WES. Transcript expression and protein levels of the familial WM candidate were evaluated in the WM patient and 2 unaffected members of the kindred. Among the 10 shared candidate mutations in the twins, the authors identified a novel heterozygous germline mutation in four and a half LIM domains protein 2 (FHL2; c.G226A, p.V76M) as a familial WM-associated mutation. FHL2 appeared to be connected with reported signaling pathways and disease-driving genes such as IL6 and HCK in WM. In addition, the authors found reduced FHL2 messenger RNA and protein expression in peripheral blood samples from the patient with WM in comparison with the healthy siblings. Taken together, these findings indicate that an FHL2g226a mutation may play an important role in familial WM, and they provide new screening possibilities for familial cases. Familial clustering in Waldenström macroglobulinemia (WM) has been observed over the years. The authors performed whole exome sequencing of germline DNA samples from twins, one diagnosed with WM and the other diagnosed with immunoglobulin M monoclonal gammopathy of undetermined significance, and their healthy siblings. Among the 10 shared candidate mutations in the twins, a novel heterozygous germline mutation in four and a half LIM domains protein 2 (FHL2; c.G226A, p.V76M) was identified as the most relevant familial WM candidate through bioinformatics analysis of a public database. Also, messenger RNA and protein expression of FHL2 was significantly lower in peripheral blood mononuclear cells of the WM patient in comparison with the healthy siblings, and this suggested that the function of FHL2 was impaired when mutated.

PPARγ-p53-Mediated Vasculoregenerative Program to Reverse Pulmonary Hypertension.

In pulmonary arterial hypertension (PAH), endothelial dysfunction and obliterative vascular disease are associated with DNA damage and impaired signaling of BMPR2 (bone morphogenetic protein type 2 receptor) via two downstream transcription factors, PPARγ (peroxisome proliferator-activated receptor gamma), and p53. We investigated the vasculoprotective and regenerative potential of a newly identified PPARγ-p53 transcription factor complex in the pulmonary endothelium. In this study, we identified a pharmacologically inducible vasculoprotective mechanism in pulmonary arterial and lung MV (microvascular) endothelial cells in response to DNA damage and oxidant stress regulated in part by a BMPR2 dependent transcription factor complex between PPARγ and p53. Chromatin immunoprecipitation sequencing and RNA-sequencing established an inducible PPARγ-p53 mediated regenerative program regulating 19 genes involved in lung endothelial cell survival, angiogenesis and DNA repair including, EPHA2 (ephrin type-A receptor 2), FHL2 (four and a half LIM domains protein 2), JAG1 (jagged 1), SULF2 (extracellular sulfatase Sulf-2), and TIGAR (TP53-inducible glycolysis and apoptosis regulator). Expression of these genes was partially impaired when the PPARγ-p53 complex was pharmacologically disrupted or when BMPR2 was reduced in pulmonary artery endothelial cells (PAECs) subjected to oxidative stress. In endothelial cell-specific Bmpr2-knockout mice unable to stabilize p53 in endothelial cells under oxidative stress, Nutlin-3 rescued endothelial p53 and PPARγ-p53 complex formation and induced target genes, such as APLN (apelin) and JAG1, to regenerate pulmonary microvessels and reverse pulmonary hypertension. In PAECs from BMPR2 mutant PAH patients, pharmacological induction of p53 and PPARγ-p53 genes repaired damaged DNA utilizing genes from the nucleotide excision repair pathway without provoking PAEC apoptosis. We identified a novel therapeutic strategy that activates a vasculoprotective gene regulation program in PAECs downstream of dysfunctional BMPR2 to rehabilitate PAH PAECs, regenerate pulmonary microvessels, and reverse disease. Our studies pave the way for p53-based vasculoregenerative therapies for PAH by extending the therapeutic focus to PAEC dysfunction and to DNA damage associated with PAH progression.

LncRNA DLX6-AS1 aggravates the development of ovarian cancer via modulating FHL2 by sponging miR-195-5p

BackgroundOvarian cancer (OC) is a huge burden on women’s lives. Recently, the implication of long non-coding RNAs (lncRNAs) in cancers, including OC, has aroused much attention. The objective of this study was to explore the role and functional mechanism of lncRNA distal-less homeobox 6 antisense 1 (DLX6-AS1) in OC.MethodsThe expression of DLX6-AS1, miR-195-5p, and four and a half LIM domains protein 2 (FHL2) was measured by quantitative real-time polymerase chain reaction (qRT-PCR). The cell proliferation, apoptosis, migration, and invasion were assessed by cell count kit 8 (CCK-8), flow cytometry and transwell assays, respectively. The protein levels of proliferating cell nuclear antigen (PCNA), cleaved-caspase-3 (C-caspase 3), N-cadherin, Vimentin, E-cadherin and FHL2 were quantified by western blot. The relationship between miR-195-5p and DLX6-AS1 or FHL2 was predicted by bioinformatics tool starBase and verified by luciferase reporter assay and RNA immunoprecipitation (RIP) assay. Xenograft tumor model was established to observe the role of DLX6-AS1 in vivo.ResultsDLX6-AS1 and FHL2 were up-regulated in OC tissues and cells, while miR-195-5p was down-regulated. DLX6-AS1 knockdown inhibited proliferation, migration, and invasion but induced apoptosis of OC cells. However, miR-195-5p inhibition reversed these effects. Overexpression of miR-195-5p also depleted proliferation, migration, and invasion but promoted apoptosis of OC cells, while FHL2 overexpression overturned these influences. DLX6-AS1 knockdown blocked tumor growth in vivo.ConclusionDLX6-AS1, as an oncogene in OC, accelerated tumor progression by up-regulating FHL2 via mediating miR-195-5p, suggesting that DLX6-AS1 was a hopeful target for the lncRNA-targeted therapy in OC.

Expression, location and biological effects of four and a half LIM domain protein2 (FHL2) on granulosa cells in ovine.

Previous studies have shown that four and a half LIM domain protein 2(FHL2) plays an essential role in the regulation of follicular development in mammals. Although the FHL2 genes of human and mouse have been well characterized, the expression and location of FHL2 in ovary and the biological functions of FHL2 on granulosa cells (GCs) of ovine are still not clear. In this study, full-length complementary DNA (cDNA) of FHL2 from ovine follicular GCs was amplified by real-time PCR (RT-PCR). The expression and location of FHL2 in ovary and GCs of ovine were studied by immunohistochemistry and immunofluorescence, and the biological effects of FHL2 on the cell proliferation, cell apoptosis, cell cycles and expression level of related genes of ovine GCs were also explored by overexpression or knockdown of FHL2. The results indicated that FHL2 was expressed in ovine follicular GCs and the sequence of the FHL2 cDNA was consistent with that predicted in GenBank, which did not cause an amino acid change. According to the results, FHL2 was expressed in ovine ovary and mainly located in the cytoplasm and nucleus of GCs. In addition, overexpression of FHL2 significantly reduced the cell viability, promoted the cell apoptosis and decreased the percentage of G0/G1 and S phase cells. RT-PCR showed that overexpression of FHL2 significantly increased the mRNA expression level of Bax and decreased the expression of Bcl-2 and the Bcl-2/Bax mRNA ratio compared with the control group. Besides, the knockdown of FHL2 gene in ovine GCs significantly improved the cell viability, suppressed the cell apoptosis, decreased the mRNA expression level of Caspase-3 gene, increased the Bcl-2/Bax mRNA ratio and increased the percentage of S and G2/M phase cells. Our results suggest that FHL2 may play an important role in the biological functions of GCs in ovine.

Four and a half LIM domains protein 1 can be as a double-edged sword in cancer progression.

Four and a half LIM domains protein 1 (FHL1), as the name suggests, contains four and a half LIM domains capable of interacting with various molecules, including structural proteins, kinases, and transcriptional machinery. FHL1 contains a zinc-finger domain and performs diverse roles in regulation of gene transcription, cytoarchitecture, cell proliferation, and signal transduction. Several studies have validated the importance of FHL1 in muscle development, myopathy, and cardiovascular diseases. Mutations in the FHL1 gene are associated with various myopathies. Recently, FHL1 was identified as a major host factor for chikungunya virus (CHIKV) infection in both humans and mice. Based on more recent findings over the last decade, FHL1 is proposed to play a dual role in cancer progression. On the one hand, FHL1 expression is suppressed in several cancer types, which correlates with increased metastatic disease and decreased survival. Moreover, FHL1 is reported to inhibit tumor cell growth and migration by associating with diverse signals, such as TGF-β and ER, and therefore considered a tumor suppressor. On the other hand, FHL1 can function as an oncogenic protein that promotes tumor progression upon phosphorylation, reflecting complex roles in cancer. This review primarily focuses on the dual role and underlying mechanisms of action of FHL1 in human cancer progression and its clinical relevance.

MicroRNA-663 Regulates Melanoma Progression by Inhibiting FHL3.

microRNA-663a (miR-663a) was reported to be highly expressed in cancers. However, its roles in melanoma progression remain unclear. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) was conducted to measure miR-663a expression level in melanoma cell lines and normal cells. Cell counting kit-8 assay, wound-healing assay, and transwell invasion assay were conducted to analyze biological roles of miR-663a in melanoma. Luciferase activity reporter assay was conducted to validate the connection of miR-663a and Four and a half LIM domain (FHL) protein 3 (FHL3) in melanoma. Our results showed miR-663a expression level was significantly increased in melanoma cells compared with normal cells. Silencing miR-663a expression suppresses melanoma cell proliferation, migration, and invasion in vitro. Moreover, FHL3 was validated as a functional target of miR-663a. Knockdown of FHL3 partially rescued the inhibitory effects of miR-663a inhibitor on melanoma cell behaviors. Together, our work provided evidence that miR-663a functions as an oncogenic miRNA in melanoma.

Quantitative Proteomic Characterization Associated with Woody Breast Meat from Broilers Fed a Standard or an Amino Acid-Reduced Diet

ObjectivesWoody or wooden breast (WB) is an emergent myopathy of broilers and is macroscopically characterized by hardened areas of the Pectoralis major muscle. Woody broiler breast fillets can result in harder texture, higher pH, lower amounts of proteins, lower water-holding capacity, and increased cook loss when compared to normal breasts. The impaired meat quality of WB has been reported to be closely associated with improved nutrition and fast-growth rates. The present research compared the proteome of normal and woody breast muscle from broilers that were fed with either a control diet or an amino acid (AA)-reduced diet.Materials and MethodsMixed-sex broilers were assigned to 16 pens (15 chicks per pen) and fed with control or reduced AA diets (20% reduction of digestible lysine, total sulfur amino acids, and threonine). At 8 wk of age, live broilers were evaluated manually for WB myopathy. Within each diet group, 4 male broilers with normal breast and 4 male broilers with WB were selected (one bird in each pen) and euthanized using CO2 gas. The breast muscle from the cranial portion was immediately sampled after bleeding and snap-frozen in liquid nitrogen. All experimental procedures were approved by the Institutional Animal Care and Use Committee of Mississippi State University (IACUC-16-542). Whole muscle proteins of normal and woody breast were extracted from frozen samples of three birds within each treatment. Two-dimensional gel electrophoresis (2-DE; 6 gels per treatment) coupled with image analysis and mass spectrometry were used to investigate differences in the expression levels of proteins (more than 2.0-fold intensity differences) from chicken breast muscle. Differences were evaluated using Student’s t test at a confidence interval of 95%.ResultsWhen the broilers were fed with the control diet, 10 proteins were expressed differentially between normal and woody breasts. Apolipoprotein A-I, desmin, annexin A2, annexin A5, and ubiquitin carboxyl-terminal hydrolase were overexpressed (P &lt; 0.05) in WB. Peptidyl-prolyl cis-trans isomerase, four and a half LIM domains protein 1 isoform X3, and an uncharacterized protein were only present in WB muscle, but not in normal chicken breast. Two proteins, keratin, type II cytoskeletal 8 and α-1,4 glucan phosphorylase, were overexpressed (P &lt; 0.05) in normal chicken breast. These differentially expressed proteins were involved in glycolytic metabolism, cell structure, and cellular defense.Interestingly, only one protein (heat shock protein β-1) was expressed differentially between normal and woody breasts when broilers were fed with the AA-reduced diet. This protein was overexpressed (P &lt; 0.05) in WB samples and found to play a role in stress resistance and actin organization.ConclusionThe protein profiles of normal and woody chicken breast samples were different, which might help explain the changes in meat quality. Essential amino acid intake resulted in minimizing difference in protein profiles between normal and woody chicken breasts.

Deletion of the FHL2 gene attenuates intima-media thickening in a partially ligated carotid artery ligated mouse model.

The four and a half LIM domain protein 2 (FHL2) is a member of the four and a half LIM domain (FHL) gene family, and it is associated with cholesterol‐enriched diet‐promoted atherosclerosis. However, the effect of FHL2 protein on vascular remodelling in response to hemodynamic alterations remains unclear. Here, we investigated the role of FHL2 in a model of restricted blood flow‐induced atherosclerosis. To promote neointimal hyperplasia in vivo, we subjected FHL2+/+ and FHL2−/− mice to partial ligation of the left carotid artery (LCA). The expression of p‐ERK and p‐AKT was decreased in FHL2−/− mice. FHL2 bound to AKT regulated AKT phosphorylation and led to Rac1‐GTP inactivation. FHL2 silencing in human aortic smooth muscle cells down‐regulated the PDGF‐induced phosphorylation of ERK and AKT. Furthermore, FHL2 silencing reduced cytoskeleton conformational changes and caused cell cycle arrest. We concluded that FHL2 is essential for the regulation of arterial smooth muscle cell function. FHL2 modulates proliferation and migration via mitogen‐activated protein kinase (MAPK) and PI3K‐AKT signalling, leading to arterial wall thickening and thus neointimal hyperplasia.

FHL1 regulates myoblast differentiation and autophagy through its interaction with LC3.

Four and a half LIM domain protein 1 (FHL1) belongs to the FHL protein family and is predominantly expressed in skeletal and cardiac muscle. FHL1 acts as a scaffold during sarcomere assembly and plays a vital role in muscle growth and development. Autophagy is key to skeletal muscle development and regeneration, with its dysfunction associated with a range of muscular pathologies and disorders. In this study, we constructed FHL1-silenced or FHL1-overexpressed myoblasts to investigate its role in autophagy during the differentiation of chicken myoblasts into myotubules. Our data showed that FHL1 contributes to myoblast differentiation as measured through MyoG, MyoD, Myh3, and Mb mRNA expression, MyoG and MyHC protein expression and the morphological characteristics of myoblasts. The results showed that FHL1 silencing inhibited the expression of ATG5 and ATG7, meanwhile, immunofluorescence and immunoprecipitation showed that FHL1 and LC3 interacted to regulate the correct formation of autophagosomes. FHL1 inhibition increased cleaved caspase-3 and PARP abundance and promoted myoblast apoptosis. Furthermore, FHL1 rescued skeletal muscle atrophy through regulating the expression of Atrogin-1 and MuRF1. Taken together, these data suggested that FHL1 regulates chicken myoblast differentiation through its interaction with LC3.

MiR-340-FHL2 axis inhibits cell growth and metastasis in ovarian cancer

Although increasing evidence indicated that deregulation of microRNAs (miRNAs) contributed to tumor initiation and progression, but little is known about the biological role of miR-340 in ovarian cancer (OC). In this study, we found that miR-340 expression was downregulated in OC tissues compared with its expression in normal ovarian epithelium and endometrium, and treatment with 5-aza-2′-deoxycytidine (5-Aza-dC) or trichostatin A (TSA) increased miR-340 expression in OC cells. In addition, ectopic miR-340 expression inhibited OC cell growth and metastasis in vitro and in vivo. Four and a half LIM domains protein 2 (FHL2) was confirmed as a direct target of miR-340 and silencing FHL2 mimicked the effects of miR-340 in OC cells. Further mechanistic study showed that miR-340 inhibited the Wnt/β-catenin pathway by targeting FHL2, as well as downstream cell cycle and epithelial-to-mesenchymal transition (EMT) signals in OC cells. Moreover, the greatest association between miR-340 and FHL2 was found in 481 ovarian serous cystadenocarcinoma tissues via pan-cancer analysis. Finally, we revealed that lower miR-340 or higher FHL2 was associated with poor OC patient outcomes. Our findings indicate that the miR-340-FHL2 axis regulates Wnt/β-catenin signaling and is involved in tumorigenesis in OC. Therefore, manipulating the expression of miR-340 or its target genes is a potential strategy in OC therapy.