Synemin Research Articles

Multiple targets related to mitochondrial function unveiled by metabolomics and proteomics profiles of hearts from atrial fibrillation patients.

Background: The prominent mitochondrial metabolic changes of the atrium reportedly have significant impact on electrical signals and structural remodeling which play important roles in the occurrence and development of atrial fibrillation (AF). However, the mechanism is not completely known. Objective: This study was aimed to explore the mitochondrial metabolism reprogrammed in AF patients by integrating metabolomics as well as proteomics of human atrium tissues. Methods and Results: Left atrial tissue samples were harvested from 10 non-valvular AF patients and 10 matched samples from healthy donors for transplantation. In metabolomics analysis, 113 metabolites were upregulated and 10 metabolites were downregulated in AF, where multiple pathways related to mitochondrial energy metabolism were enriched. Correlation analysis between the differentially expressed proteins and metabolites identified several hub proteins related to mitochondrial function including Glycerol-3-phosphate dehydrogenase 2 (GPD2), Synemin (SYNM), Plectin (PLEC), with MCC score of 27, 17, 16, respectively, which have the most interactions with the dysregulated metabolites and ranked at the top in network string interactions scored by MCC method. All 330 differentially expressed proteins including 225 upregulated and 105 downregulated molecules were revealed and analyzed, which identified the downregulation of GPD2 (p = 0.02 and FC = 0.77), PLEC (p < 0.001 and FC = 0.71) and SYNM (p = 0.04 and FC = 0.76) in AF patients. Gene Set Variation Analysis (GSEA) showed mitochondrial metabolism-associated pathways including oxidative phosphorylation (NES: -1.73) and ATP biosynthetic process (NES: -2.29), were dramatically diversified in human AF. In GSVA, the expression levels of GPD2, PLEC, and SYNM were demonstrated to be associated with multiple metabolic pathways related to mitochondrial function (e.g., lipid metabolism and AMP activated protein kinase signaling) and cardiac structural and electrical remodeling (e.g., contractile fiber, ion homeostasis), which were proven vital in the development and maintenance of AF. Conclusion: In all, this study provides new insights into understanding the mechanisms of AF progression, especially the reprogramming mitochondrial metabolism, and identifies several genes related to mitochondrial function as novel targets for AF, which may be involved in the occurrence and development of AF.

The Role of CEP55 Expression in Tumor Immune Response and Prognosis of Patients with Non-small Cell lung Cancer.

With the continuous advancement of diagnostic methods, more and more early-stage Non-small cell lung cancer (NSCLC) patients are diagnosed. Although many scholars have devoted substantial efforts to investigate the pathogenesis and prognosis of NSCLC, its molecular mechanism is still not well explained. We retrieved three gene datasets GSE10072, GSE19188 and GSE40791 from the Gene Expression Omnibus (GEO) database and screened and identified differentially expressed genes (DEGs). Then, we performed KEGG and GO functional enrichment analysis, survival analysis, risk analysis and prognosis analysis on the selected hub genes. We constructed a protein-protein interaction (PPI) network, and used the STRING database and Cytoscape software. The biological process analysis showed that these genes were mainly enriched in cell division and nuclear division. Survival analysis showed that the genes of CEP55 (centrosomal protein 55), NMU (neuromedin U), CAV1 (Caveolin 1), TBX3 (T-box transcription factor 3), FBLN1 (fibulin 1) and SYNM (synemin) may be involved in the development, invasion or metastasis of NSCLC (P<0.05, logFC>1). Prognostic analysis and independent prognostic analysis showed that the expression of these hub gene-related mRNAs was related to the prognostic risk of NSCLC. Risk analysis showed that the selected hub genes were closely related to the overall survival time of patients with NSCLC. The DEGs and hub genes screened and identified in this study will help us to understand the molecular mechanisms of NSCLC, and CEP55 expression affects the survival and prognosis of patients with NSCLC, and participates in tumor immune response.

Synemin promotes pulmonary artery smooth muscle cell phenotypic switch in shunt-induced pulmonary arterial hypertension.

Although considerable progress has been made in the diagnosis and treatment of congenital heart disease-associated pulmonary heart hypertension (CHD-PAH), the clinical prognosis and overall survival of patients with CHD-PAH remain poor. Therefore, the molecular pathogenesis of CHD-PAH requires further investigation. The intermediate filament protein synemin (SYN) is reported to modulate phenotypic alterations and varicose vein development, but there is little understanding of its exact functions in CHD-PAH. SYN expression in the pulmonary arterioles of CHD-PAH patients and shunt-induced PAH rat models was evaluated using immunohistochemistry and western blot. Cell counts and Transwell migration assays were used to assess the effect of SYN on the proliferation and migration capability of human pulmonary smooth muscle cells (hPASMCs). Adeno-associated viruses (AAVs) have been used to suppress SYN expression in the pulmonary arterioles of rats. Such rats were further used to construct a shunt-induced PAH animal model to investigate the function of SYN in PAH and pulmonary vascular remodelling. Compared with the normal control group, SYN expression was found to be clearly up-regulated in the remodelled pulmonary arterioles of CHD-PAH and shunt-induced PAH rat models. In addition, SYN suppression increased the expression of hPASMC contractile-phenotype markers and decreased the expression of synthetic phenotype markers, in contrast to the control group. SYN suppression also dramatically attenuated the proliferation and migration capability of hPASMCs. Conversely, SYN overexpression promoted phenotypic switch, proliferation, and migration of hPASMCs, whereas these effects were notably alleviated by the protein kinase B (AKT) inhibitor MK-2206. Furthermore, we confirmed that SYN suppression mitigated PAH and pulmonary vascular remodelling induced by high blood flow in vivo. Our findings indicated that SYN may represent a promising therapeutic target in the treatment of CHD-PAH.

Editorial Note on General Science and Medicine

Lung cancer is currently one of the tumor diseases with the highest incidence in the world. NSCLC is the most common type of lung cancer pathology, accounting for more than 80% of all lung cancers. With the continuous popularization and advancement of diagnostic methods such as CT imaging, more and more early-stage NSCLC patients have been diagnosed and the increasing incidence has aroused widespread attention in its pathogenesis and prognosis research. Although many scholars have devoted substantial efforts in the research on the pathogenesis and prognosis of NSCLC, its molecular mechanism is still not well explained. In order to screen and identify candidate genes for the occurrence and prognosis of NSCLC, we downloaded gene data sets GSE10072, GSE19188 and GSE40791 from the Gene Expression Omnibus (GEO) database, and screened and identified differentially expressed genes ( DEGs), and then perform KEGG and GO functional enrichment analysis, survival analysis, risk analysis, and prognosis analysis on the selected Hub genes. By constructing a protein interaction network (PPI), String and Cytoscape performed modular analysis and identified 579 differential genes, consisting of 343 up-regulated genes and 236 down-regulated genes. Seven valuable Hub genes were identified, and biological process analysis showed that these genes were mainly enriched in cell division and nuclear division. Survival analysis showed that CEP55(Centrosomal Protein 55), NMU(Neuromedin U), CAV1(Caveolin 1), TBX3(T-Box Transcription Factor 3), FBLN1(Fibulin 1), SYNM(Synemin)and METTL7A may be involved in the development, invasion or metastasis of NSCLC. Prognostic analysis and independent prognostic analysis showed that the expression of these Hub gene-related mRNAs was related to the prognostic risk of NSCLC. Risk analysis showed that the selected Hub gene was closely related to the overall survival time of patients with NSCLC. In summary, the DEGs and Hub genes screened and identified in this study will help us understand and study the molecular mechanisms of carcinogenic effects with NSCLC, and provide potential gene targeting for the diagnosis and treatment of NSCLC in the future treatment way.

Determination of distinctive hypomethylated genes in African American colorectal neoplastic lesions.

Background:Few studies have analyzed progressive demethylation in the path to cancer. This is of utmost importance, especially in populations such as African Americans, who display aggressive tumors at diagnosis, and for whom markers of early neoplastic transformation are needed. Here, we determined hypomethylated targets in the path to colorectal cancer (CRC) using Reduced Representation Bisulfite Sequencing (RRBS).Methods:DNA was extracted from fresh frozen tissues of patients with different colon lesions (normal, tubular adenoma, tubulovillous adenoma, and five cancers). RRBS was performed on these DNA extracts to identify hypomethylated gene targets. Alignment, mapping, and methylation analyses were performed. Pathways affected by the hypomethylated gene targets were determined using Ingenuity Pathway Analysis (IPA).Results:Pairwise analyses of samples led to the identification of the following novel hypomethylated genes: ELMO3 (Engulfment and cell motility 3), SLC6A2 (Solute carrier family 6 member 2), SYNM (Synemin), and HMX2 (Homeobox 2). The ELMO3 promoter was significantly hypomethylated at five CpG sites, SYNM at two CpG sites, SLC6A2 at one CpG site, and the HMX2 gene at one CpG site. IPA placed these genes within important carcinogenic pathways.Conclusions:This work provides insight into the role of hypomethylation in colon carcinogenesis in African Americans. The identified targets affected many important pathways, as demonstrated through IPA. These targets might serve as biomarkers for early diagnosis and potential targets for therapy.

The intermediate filament protein synemin (SYNM) was found to be more widespread in CD117+ gastrointestinal stromal cell tumors (GIST) than the CD34 transmembrane phosphoglycoprotein: an immunohistochemical study

ABSTRACTInterstitial cells of Cajal (ICC) are the pacemaker cells in the gastrointestinal system, initiating the rhythmic systematic contraction of smooth muscle to regulate peristalsis. Benign ICC are identified immunohistochemically by positive staining for CD117, c-kit tyrosine kinase receptor. CD117 expression is maintained during the malignant transformation of ICC into gastrointestinal stromal cell tumors (GIST). However, to date, no single reliable marker for GIST has been identified by immunohistochemical (IHC) staining, and correct diagnosis depends on IHC staining results using multiple markers. This study compared the reactivities of synemin (SYNM) intermediate filament protein and CD34, a known marker for stem cells, endothelial cells, and many GIST tumors, in 54 formalin-fixed, paraffin-embedded GIST, which were determined by this study to be CD117 positive. Double-immunofluorescence (IF) staining was also used to assess whether CD117 and SYNM were co-expressed by ICC. While 81.5% of the GIST were CD34+, 92.9% of these tumors were SYNM+. ICC were CD117+/SYNM+, whereas mast cells were CD117+/SYNM−. Because the percentage of CD117+/SYNM+ GIST was higher than the percentage of 117+/CD34+ GIST, this study suggested that SYNM was a better marker than CD34 for GIST diagnosis. In addition, differential expression of SYNM and CD117 helped distinguish between ICC and mast cells.

A novel heterozygous variant p.(Trp538Arg) of SYNM is identified by whole‐exome sequencing in a Chinese family with dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is a relatively frequent myocardial disease that may lead to heart failure, syncope, and sudden cardiac death. Genetic factors play important roles in the etiology of the disease. To date, at least 50 genes have been identified in patients with DCM, among them, only three mutations have been reported in Synemin (SYNM) gene. In this study, we investigate a Chinese family of three generations with four patients with DCM. Employing whole-exome sequencing (WES) and bioinformatics strategies, a novel heterozygous missense mutation p.(Trp538Arg) of SYNM was identified and cosegregated with the affected family members. The missense mutation locates in the C-terminal domain of SYNM and leads to a substitution of tryptophan by arginine and may cause the structure change of synemin protein. In conclusion, we employed WES to detect the mutations of DCM patients and identified a novel likely pathogenic mutation in SYNM gene. Our study not only expands the spectrum of SYNM mutations, it further confirms that mutations in SYMN may underlie nonfamilial DCM, and offers genetic testing information to additional DCM patients.

PO-122 Synemin is a novel co-regulator of non-homologous end joining in head and neck cancer cells

Introduction Cancer therapy resistance is one of the major obstacles for higher cure rates. Novel key players of the resistome are focal adhesion proteins (FAPs). As FAPs are critically involved in DNA repair, we here characterise the yet unknown function of the FAP and intermediate filament protein Synemin (SYN) as a novel DNA repair regulator and potential cancer drug target in head and neck squamous cell carcinoma (HNSCC). Material and methods Our novel 3D High Throughput esiRNA Screen (3DHTesiRNAs) using laminin-rich extracellular matrix (lrECM) was conducted to measure radiation-induced residual DNA double strand breaks (DSBs; foci assay) and clonogenic radiation survival in UTSCC15-pEGFP-53BP1 cells. Validations were performed in 10 additional HNSCC cell lines in 3D lrECM. Upon SYN depletion, DSB repair reporter assays for non-homologous end joining (NHEJ) and homologous recombination (HR) as well as Western Blotting for protein expression and phosphorylation were carried out. SYN depleted cells with and without irradiation were analysed for kinase activity profiling (PamGene) and protein interactome determination using a sequential immunoprecipitation/mass spectrometry approach. Results and discussions Among the targets found in the 3DHTesiRNAs, SYN turned out as one of the top FAP candidate determinants of HNSCC cell survival. SYN silencing radiosensitized HNSCC cells, while its exogenous overexpression induced radioprotection. We found an increased SYN/chromatin interaction and a marked perinuclear SYN accumulation post irradiation. Intriguingly, SYN depletion elicited a 40% reduction in NHEJ activity without affecting HR or alt-EJ. In line, ATM, DNA-PKcs and c-Abl phosphorylation as well as Ku70 expression strongly declined in SYN depleted and irradiated cells relative to controls and, in contrast, to the rescue of these protein modifications by SYN overexpression. Single, double and triple depletion of SYN, DNA-PKcs and c-Abl resulted in similar radiosensitization and DSB levels as observed for SYN only, suggesting its upstream role. In the kinome analysis we observed variable changes in the serine/threonine kinases, in contrast to the tyrosine kinases with a pronounce reduced kinase activity after SYN silencing. Conclusion Our data suggest the intermediate filament SYN as a new important determinant of DNA repair, tyrosine kinome and radioresistance of HNSCC cells. These observations further support the notion that DNA repair is controlled by cooperative interactions between nuclear and cytoplasmic proteins.

Intermediate filament dynamics and breast cancer: Aberrant promoter methylation of the Synemin gene is associated with early tumor relapse

Synemin (SYNM) is a type IV intermediate filament that has recently been shown to interact with the LIM domain protein zyxin, thereby possibly modulating cell adhesion and cell motility. Owing to this multiplicity of potential functions relevant to cancer development, we initiated a study to decipher SYNM expression and regulation in benign human breast tissue and breast cancer. Dot blot array analysis showed significant SYNM mRNA downregulation in 86% (n=100, P<0.001) of breast cancers compared with their normal tissue counterparts, a result that was confirmed by real-time PCR analysis (n=36, P<0.0001). Immunohistochemistry analysis showed abundant SYNM protein expression in healthy myoepithelial breast cells, whereas SYNM expression loss was evident in 57% (n=37, P<0.001) of breast cancer specimens. Next, we analyzed methylation of the SYNM promoter to clarify whether the SYNM gene can be silenced by epigenetic means. Indeed, methylation-specific PCR analysis showed tumor-specific SYNM promoter methylation in 27% (n=195) of breast cancers. As expected, SYNM promoter methylation was tightly associated (P<0.0001) with SYNM expression loss. In-depth analysis of the SYNM promoter by pyrosequencing showed extensive CpG methylation of DNA elements supposed to regulate gene transcription. Demethylating treatment of SYNM methylated breast cancer cell lines with 5-aza-2-deoxycytidine clearly reestablished the SYNM expression. Statistical analysis of the patient cohort showed a close association between SYNM promoter methylation and unfavorable recurrence-free survival (hazard ratio=2.941, P=0.0282). Furthermore, SYNM methylation positively correlated with lymph node metastases (P=0.0177) and advanced tumor grade (P=0.0275), suggesting that SYNM methylation is associated with aggressive forms of breast cancer. This is the first study on the epigenetic regulation of the SYNM gene in a cancer entity. We provide first hints that SYNM could represent a novel putative breast tumor suppressor gene that is prone to epigenetic silencing. SYNM promoter methylation may become a useful predictive biomarker to stratify breast cancer patients' risk for tumor relapse.