Search Results (63)

CircRNAs are key regulators of gene expression. The functional roles of exonic versus exon–intron circRNAs in early breast cancer remain unclear. Connexin-43 (GJA1) generates exonic circRNA (ecircRNA) hsa_circ_0077755 (circ_755) and exon–intron circRNA (EIcircRNA), hsa_circ_0077753 (circ_753), both linked to increased breast cancer risk. We examined their structural, molecular, and phenotypic roles in transient and stable knockdown S1 breast epithelial cells, using RT-qPCR, dual-luciferase, lumen formation and invasion assays, and extracellular vesicle (EV) analysis. Knockdown of cytoplasm-enriched circ_755 reduced Connexin-43 transcript and protein, whereas knockdown of nuclear-enriched circ_753 preserved GJA1. Both induced lumen disruption, β-catenin disorganization, increased invasion, and regulated onco-miR-182. More pronounced miR-182 upregulation and broader repression of tumor-suppressive targets (BCL2, FOXO1, RECK) were observed in circ_753 knockdown cells, alongside concurrent depletion of hsa_circ_0008932 (circ_8932), which is predicted to interact with miR-182. Similar reciprocal changes in circRNA/miR-182 were observed in released EVs. These data highlight circRNA-miR-182 networks with distinct effects on tumor initiation and potential value as breast cancer biomarkers. Full article

We present a family of five siblings who came to our attention with a clinical and radiological diagnosis of familial hypomyelinating leukodystrophy. Despite brain white matter abnormalities being present in all siblings, the clinical phenotype was variable: the three brothers presented with a clear-cut late-onset spastic paraplegia, whereas the two sisters displayed only mild pyramidal signs. Molecular analysis revealed a single relevant variant shared by all affected siblings, namely the likely pathogenic variant c.659C>T (p.Ser220Phe) in the GJA1 gene. Variants in this gene are generally associated with oculodentodigital dysplasia (ODDD), an autosomal dominant condition characterized by distinctive facial features and anomalies of the eyes, teeth, and digits. Neurological features are reported in about 30% of cases. In this family, ODDD manifested as a predominantly neurological phenotype. Although a clear explanation for this uncommon presentation is lacking, shared genetic modifiers, the effect of the specific variant, and a possible patient-population bias may have contributed. This case highlights the wide phenotypic spectrum of CX43-related disorders and suggests the importance of testing the GJA1 gene in individuals with atypical presentations, including predominant or isolated neurological phenotypes such as late-onset spastic paraplegia. MRI findings may also provide a useful diagnostic clue when ODDD is suspected. Full article

Microphthalmia, anophthalmia and ocular coloboma (MAC) are rare developmental eye disorders. Although over 100 causative genes have been identified, the molecular spectrum and genotype–phenotype correlations remain incompletely understood, particularly in genetically diverse populations. We set out to molecularly characterize MAC in the Israeli population. Forty-seven MAC-affected individuals from 43 unrelated families were enrolled. DNA of all probands was subjected to whole exome sequencing. The most common phenotype was microphthalmia (64% of patients). Definite or possible molecular diagnoses were achieved in 13/43 probands (30%) and involved 10 different genes (MFRP, SMO, GJA8, SOX2, RARB, TSPAN12, SHH, PTPN11, BEST1, and TP63). An in vitro splicing assay was used to explore the pathogenicity of a variant in the SMO gene. Following stringent filtering of exome data, 226 rare possibly pathogenic variants were identified in 218 genes not previously associated with MAC. The rate of molecular diagnosis achieved in this Israeli MAC cohort is similar to the reported range in other studies. The results further demonstrate the genetic heterogeneity of MAC, while supporting the involvement of complex inheritance and/or environmental factors in many of the cases. Further studies are required to reveal these underlying etiological factors, and to support the novel genotype–phenotype associations suggested here. Full article

Background/Objectives: Atrial fibrillation (AF), characteristic of chaotic atrial electrical activity along with ineffective atrial systole, remains the most frequent sustained cardiac dysrhythmia, with an overall lifetime risk for AF being approximately 15% to 40% in the global population. AF is associated with substantially enhanced risks for multiple adverse clinical outcomes, including thromboembolic cerebral stroke, dementia, chronic kidney disease, myocardial infarction, cardiac failure, and even premature cardiac demise. Although remarkable advances have been achieved toward unravelling the complex hereditary etiopathogenesis underpinning AF, it has become increasingly clear that inherited determinants predisposing to AF in a vast majority of individuals are still uncertain. Methods: A Chinese pedigree with idiopathic AF and another group of 236 cases suffering idiopathic AF along with 312 unrelated healthy volunteers were prospectively recruited. Exome-wide sequencing and Sanger sequencing assays were implemented in research participants. The functional effects of the discovered variations in the SOX5 gene were explored through dual-luciferase reporter analysis. Results: Two novel SOX5 mutants, NM_006940.6: c.355C>T; p.(Gln119*) and NM_006940.6: c.640G>T; p.(Glu214*), were identified in the AF pedigree and one of the 236 unrelated patients affected with AF, respectively. These two heterozygous truncating SOX5 variations were absent from the 624 control chromosomes. Quantitative luciferase reporter assays unraveled that both Gln119*- and Glu214*-mutant SOX5 lost the ability to transactivate GJA1. Additionally, the two variations abolished the synergistic transactivation of SCN5A by SOX5 and SHOX2. Conclusions: The current findings indicate SOX5 as a novel gene contributing to AF, which adds more insight to the molecular pathogenesis of AF, and provides a potential target for personalized precision medicine. Full article

Background: Doxorubicin (DOX) is a widely used chemotherapeutic agent, but its efficacy is often limited by cancer cell resistance. Although multiple DOX resistance mechanisms have been characterized, the global transcriptomic alterations underlying this phenomenon remain poorly understood. The aim of this work was to determine whether a common transcriptional response associated with DOX desensitization exists across tumor cells of different origins and to identify the core elements of this response. Methods: We performed an integrated bioinformatics analysis, including: analysis of independent transcriptomic datasets (comparing DOX-resistant neuroblastoma, breast, and cervical carcinoma cells to their DOX-sensitive counterparts), functional annotation of differentially expressed genes, reconstruction and topology analysis of gene networks, text mining, and survival analysis. The findings were validated through in vitro functional tests, RT-PCR, and analysis of the Cancer Therapeutics Response Portal and The Cancer Genome Atlas. Results: We showed that DOX resistance in cancer cells is associated with cytoskeletal reorganization, modulation of cell adhesion, cholesterol biosynthesis, and dysregulation of mTORC1, Wnt, and Gβγ signaling pathways. Network analysis identified a conserved regulome of 37 resistance-linked genes, with GJA1, SEH1L, TCF3, TUBA4A, and ZYX emerging as central hubs (mean degree: 8.7–19.7; mean fold change: 2.4–21.3). Experimental validation in DOX-resistant KB-8-5 cervical carcinoma cells and their sensitive counterparts (KB-3-1) confirmed enhanced cellular adhesion and reduced intracellular cholesterol levels associated with chemoresistance, supporting our in silico findings. A detailed follow-up analysis verified the upregulation of these hub genes in chemoresistant cells and their correlation with poor clinical outcomes across multiple cancer types. Conclusions: This integrative analysis identifies conserved transcriptomic signatures of DOX resistance and highlights hub genes GJA1, SEH1L, TCF3, TUBA4A, and ZYX with potential as predictive biomarkers and therapeutic targets. Targeting these pathways may help overcome chemoresistance and improve treatment outcomes in cancer patients. Full article

Background: The Space Omics and Medical Atlas (SOMA) is an extensive database containing gene expression information from samples collected during the short-duration Inspiration4 spaceflight mission in 2021. Given our prior understanding of the genetic basis for cardiovascular diseases in spaceflight, including orthostatic intolerance and cardiac deconditioning, we aimed to characterize changes in differential gene expression among astronauts using SOMA-derived data and curated cardiovascular pathways. Methods: Using the KEGG 2021 database, we curated a list of genes related to cardiovascular adaptations in spaceflight, focusing on pathways such as fluid shear stress and atherosclerosis, lipid metabolism, arrhythmogenic ventricular hypertrophy, and cardiac muscle contraction. Genes were cross-matched to spaceflight-relevant datasets from the Open Science Data Repository (OSDR). Differential expression analysis was performed using DESeq2 (v1.40.2, R) with normalization by median-of-ratios, paired pre-/post-flight covariates, and log2 fold change shrinkage using apeglm. Differentially expressed genes (DEGs) were defined as |log2FC| ≥ 1 and FDR < 0.05 (Benjamini–Hochberg correction). Module score analyses were conducted across SOMA cell types to confirm conserved cardiac adaptation genes. Results: A total of 185 spaceflight-relevant genes were analyzed. Statistically significant changes were observed in immune-related cardiovascular pathways, particularly within monocytes and T cells. Persistent upregulation of arrhythmogenic genes such as GJA1 was noted at post-flight day 82. WikiPathways enrichment revealed additional pathways, including focal adhesion, insulin signaling, and heart development. Conclusions: Short-duration spaceflight induces significant gene expression changes that are relevant to cardiovascular disease risk. These changes are mediated largely through immune signaling and transcriptional regulation in peripheral blood mononuclear cells. Findings highlight the need for tailored countermeasures and longitudinal monitoring in future long-duration missions. Full article

Background: As a pivotal point for the development of liver diseases, liver fibrosis (LF) is closely associated with cellular senescence and ferroptosis. However, there is a lack of effective markers that accurately predict LF status. This study aims to identify key genes involved in LF through bioinformatics analysis and experimental validation. Methods: We used bioinformatics analysis of Gene Expression Omnibus (GEO) data to investigate the gene functions, prognostic value, and immune associations of characteristic genes in LF. Functional enrichment analysis of DEGs was performed using GO and KEGG. Immune cell types and their proportions were estimated with CIBERSORTx. In addition, we analyzed the role of NQO1 in LF using IHC, WB, PCR, and flow cytometry. Results: Bioinformatics analysis identified 10 hub genes, including AR, CDKN1A, GJA1, CTSB, HIF1A, HMGB1, NQO1, PARP1, PTEN, and TXN. Among them, NQO1 was strongly correlated with immune cell activity. Experimental validation confirmed that NQO1 is upregulated and promotes αSMA and COL1A1 expression in hepatic stellate cells (HSCs). Knockdown of NQO1 significantly affected the proliferation of HSCs. Conclusions: NQO1 plays a critical role in HSC senescence and ferroptosis, promoting HSC activation and contributing to LF progression. Our findings suggest that NQO1 may serve as a potential biomarker for LF. Full article

Background: This paper will identify the potential genetic causes of multimorbidity associated with autosomal dominant congenital cataract (ADCC). Methods: Whole exome sequencing (WES) was performed on 13 individuals affected with ADCC. Subsequent bioinformatic analyses identified variants with deleterious pathogenicity scores. Results: Disease-causing variants were identified in 8 genes already linked to cataract (CHMP4B, CRYAA, CRYBA1, CRYGD, CYP21A2, GJA8, OPA1, and POMGNT1), but variants previously associated with systemic disorders were also found in a further 11 genes (ACTL9, ALDH18A1, CBS, COL4A3, GALT, LRP5, NOD2, PCK2, POMT2, RSPH4A, and SMO). All variants were identified via pipeline data analysis, prioritising rare coding variants using Kaviar and the Genome Aggregation Database. The following ADCC-associated non-ocular phenotypes were identified in four patients in the cohort: (i) Horner’s pupils, vaso-vagal syncope, and paroxysmal orthostatic tachycardia syndrome; (ii) reduced kidney function and high cholesterol; (iii) hypertension, high cholesterol, and kidney stones; and (iv) grade 1 spondylolysis. Conclusions: We report 11 novel genes identified in an ADCC patient cohort associated with systemic disorders found, along with 8 known cataract-causing genes. Our findings broaden the spectrum of potentially cataract-associated genes and their related lens phenotypes, as well as evidence multimorbidities in four patients, highlighting the importance of careful multisystem phenotyping following genetic analysis. Full article

The largest area in the adult mammalian brain that contains stem and progenitor cells at different stages of differentiation is the subventricular zone located along the lateral wall of the lateral ventricle. We have previously shown in adult monkeys that transient global cerebral ischemia upregulates the expression of hundreds of genes in this zone, including genes known to be related to stemness in the rodent brain. Here, we analyzed the immunophenotype of two of these genes, TNC and GJA1, by co-expression experiments, applying a panel of known stem/progenitor-cell-related markers. We found that both TNC and GJA1 were expressed in the perivascular region. They were localized not to the endothelial cells but to the periendothelial adventitial cells, which was consistent with our previous electron-microscopic data suggesting periendothelial cells as a source of progenitors. We report that the expression of GJA1 was high in quiescent progenitors, while TNC was mostly present in progenitors in the transition from a quiescent to an active state. Our data suggest that TNC and GJA1 can be used as markers for stem/progenitor cells in the largest stem cell area of the adult primate brain. Full article

The Connexin43 transmembrane protein (Cx43), encoded by the GJA1 gene, is a member of a multigenic family of proteins that oligomerize to form hemichannels and intercellular channels, allowing gap junctional intercellular communication between adjacent cells or communication between the intracellular and extracellular compartments. Cx43 has long been shown to play a significant but complex role in cancer development, acting as a tumor suppressor and/or tumor promoter. The effects of Cx43 are associated with both channel-dependent and -independent functionalities and differ depending on the expression level, subcellular location and the considered stage of cancer progression. Recently, six isoforms of Cx43 have been described and one of them, called GJA1-20k, has also been found to be expressed in cancer cells. This isoform is generated by alternative translation and corresponds to the end part of the fourth transmembrane domain and the entire carboxyl-terminal (CT) domain. Initial studies in the cardiac model implicated GJA1-20k in the trafficking of full-length Cx43 to the plasma membrane, in cytoskeletal dynamics and in mitochondrial fission and subcellular distribution. As these processes are associated with cancer progression, a potential link between Cx43 functions, mitochondrial activity and GJA1-20k expression can be postulated in this context. This review synthetizes the current knowledge on GJA1-20k and its potential involvement in processes related to epithelial-to-mesenchymal transition (EMT) and the proliferation, dissemination and quiescence of cancer cells. Particular emphasis is placed on the putative roles of GJA1-20k in full-length Cx43 exportation to the plasma membrane, mitochondrial activity and functions originally attributed to the CT domain. Full article

The World Health Organization has classified air pollution as a carcinogen, and polycyclic aromatic hydrocarbons (PAHs) are major components of air particulates of carcinogenic concern. Thus far, most studies focused on genotoxic high molecular weight PAHs; however, recent studies indicate potential carcinogenicity of the non-genotoxic lower molecular weight PAHs (LMW PAHs) that are found in indoor and outdoor air pollution as well as secondhand cigarette smoke. We hypothesize that LMW PAHs contribute to the promotion stage of cancer when combined with benzo[a]pyrene (B[a]P), a legacy PAH. We specifically determined the effects of an LMW PAH mixture containing 1-methylanthracene (1MeA), fluoranthene (Flthn), and phenanthrene (Phe) combined with B[a]P on lung tumor promotion. To test this hypothesis, we used a two-stage, initiation/promotion BALB/ByJ female lung tumor mouse model. The mice were initiated with 3-methylcholanthrene followed by exposures to B[a]P, the LMW PAH mixture, and the combination of the LMW PAH mixture plus B[a]P, all at 10 mg/kg. The LMW PAHs combined with B[a]P significantly increased the promotion and incidence of lung tumors over that of B[a]P alone. The LMW PAHs in the absence of B[a]P did not significantly promote tumors, indicating strong co-promotional activities. We further assessed the effects of these PAHs on other hallmarks of cancer, namely, bronchoalveolar lavage fluid inflammatory infiltrates, pro-inflammatory transcripts, KC protein content, and mRNA expression of the gap junction (Gja1) and epiregulin (Ereg) genes. The LMW PAHs increased the biomarkers of inflammation, decreased Gja1 expression, and increased Ereg expression, all consistent with tumor promotion. This study indicates that non-genotoxic LMW PAHs can contribute to the cancer process and warrants further studies to assess the carcinogenic risks of other LMW PAHs. Full article

Background: Atrial fibrillation (AF) signifies the most prevalent supraventricular arrhythmia in humans and may lead to cerebral stroke, cardiac failure, and even premature demise. Aggregating strong evidence points to genetic components as a cornerstone in the etiopathogenesis of familial AF. However, the genetic determinants for AF in most patients remain elusive. Methods: A 4-generation pedigree with idiopathic AF and another cohort of 196 unrelated patients with idiopathic AF as well as 278 unrelated healthy volunteers were recruited from the Chinese population of Han ethnicity. A family-based whole-exome sequencing examination followed by a Sanger sequencing assay in all research subjects was implemented. The functional impacts of the identified SOX4 mutations were explored via a dual-reporter assay. Results: Two new heterozygous SOX4 mutations, NM_003107.3: c.211C>T; p.(Gln71*) and NM_003107.3: c.290G>A; p.(Trp97*), were observed in the family and 1 of 196 patients with idiopathic AF, respectively. The two mutations were absent in the 278 control individuals. The biochemical measurements revealed that both Gln71*- and Trp97*-mutant SOX4 failed to transactivate GJA1 (Cx43). Moreover, the two mutations nullified the synergistic activation of SCN5A by SOX4 and TBX5. Conclusions: The findings first indicate SOX4 as a gene predisposing to AF, providing a novel target for antenatal genetic screening, individualized prophylaxis, and precision treatment of AF. Full article

Background: Earlier studies have established that culturing human ovarian tissue in a 3D system with a small amount of soluble Matrigel (a basement membrane protein) for 7 days in vitro increased gene fusion and alternative splicing events, cellular functions, and potentially impacted gene expression. However, this method was not suitable for in vitro culture of human testicular tissue. Objective: To test a new method for long-time in vitro culture of testicular fragments, thawed with two different regimes, with evaluation of transcriptomic differences by RNA sequencing. Methods: Testicular tissue samples were collected, cryopreserved (frozen and thawed), and evaluated immediately after thawing and following one week of in vitro culture. Before in vitro culture, tissue fragments were encapsulated in fibrin. Four experimental groups were formed. Group 1: tissue quickly thawed (in boiling water at 100 °C) and immediately evaluated. Group 2: tissue quickly thawed (in boiling water at 100 °C) and evaluated after one week of in vitro culture. Group 3: tissue slowly thawed (by a physiological temperature 37 °C) and immediately evaluated. Group 4: tissue slowly thawed (by a physiological temperature 37 °C) and evaluated after one week of in vitro culture. Results: There are the fewest differentially expressed genes in the comparison between Group 2 and Group 4. In this comparison, significantly up-regulated genes included C4B_2, LOC107987373, and GJA4, while significantly down-regulated genes included SULT1A4, FBLN2, and CCN2. Differential genes in cells of Group 2 were mainly enriched in KEGG: regulation of actin cytoskeleton, lysosome, proteoglycans in cancer, TGF-beta signaling pathway, focal adhesion, and endocytosis. These Group 2- genes were mainly enriched in GO: spermatogenesis, cilium movement, collagen fibril organization, cell differentiation, meiotic cell cycle, and flagellated spermatozoa motility. Conclusions: Encapsulation of testicular tissue in fibrin and long-time in vitro culture with constant stirring in a large volume of culture medium can reduce the impact of thawing methods on cryopreserved testicular tissue. Full article

Connexin 43 (Cx43) is crucial for the development and homeostasis of the musculoskeletal system, where it plays multifaceted roles, including intercellular communication, transcriptional regulation and influencing osteogenesis and chondrogenesis. Here, we investigated Cx43 modulation mediated by inflammatory stimuli involved in osteoarthritis, i.e., 10 ng/mL Tumor Necrosis Factor alpha (TNFα) and/or 1 ng/mL Interleukin-1 beta (IL-1β), in primary chondrocytes (CH) and osteoblasts (OB). Additionally, we explored the impact of synovial fluids from osteoarthritis patients in CH and cartilage explants, providing a more physio-pathological context. The effect of TNFα on Cx43 expression in cartilage explants was also assessed. TNFα downregulated Cx43 levels both in CH and OB (−73% and −32%, respectively), while IL-1β showed inconclusive effects. The reduction in Cx43 levels was associated with a significant downregulation of the coding gene GJA1 expression in OB only (−65%). The engagement of proteasome in TNFα-induced effects, already known in CH, was also observed in OB. TNFα treatment significantly decreased Cx43 expression also in cartilage explants. Of note, Cx43 expression was halved by synovial fluid in both CH and cartilage explants. This study unveils the regulation of Cx43 in diverse musculoskeletal cell types under various stimuli and in different contexts, providing insights into its modulation in inflammatory joint disorders. Full article

Differences in structural and functional properties between oocytes and cumulus cells (CCs) may cause low vitrification efficiency for cumulus–oocyte complexes (COCs). We have suggested that the disconnection of CCs and oocytes in order to further cryopreservation in various ways will positively affect the viability after thawing, while further co-culture in vitro will contribute to the restoration of lost intercellular gap junctions. This study aimed to determine the optimal method of cryopreservation of the suspension of CCs to mature GV oocytes in vitro and to determine the level of mRNA expression of the genes (GJA1, GJA4; BCL2, BAX) and gene-specific epigenetic marks (DNMT3A) after cryopreservation and in vitro maturation (IVM) in various culture systems. We have shown that the slow freezing of CCs in microstraws preserved the largest number of viable cells with intact DNA compared with the methods of vitrification and slow freezing in microdroplets. Cryopreservation caused the upregulation of the genes Cx37 and Cx43 in the oocytes to restore gap junctions between cells. In conclusion, the presence of CCs in the co-culture system during IVM of oocytes played an important role in the regulation of the expression of the intercellular proteins Cx37 and Cx43, apoptotic changes, and oocyte methylation. Slow freezing in microstraws was considered to be an optimal method for cryopreservation of CCs. Full article