👤 Emilija Mihailović

Familial hypercholesterolemia (FH) is characterised by elevated low-density lipoprotein cholesterol (LDL-C) levels and an increased risk of premature cardiovascular disease. The present study aimed to investigate the genetic background, associated biochemical profiles, clinical manifestations, and therapeutic response in patients with clinically suspected FH in Serbia. A total of 101 patients with clinically suspected FH were recruited from the Clinic for Endocrinology, Diabetes and Metabolic Diseases in Serbia between 2015 and 2023. Clinical diagnosis was established using the Dutch Lipid Clinic Network (DLCN) criteria. Genetic profiles of all patients were previously determined using next-generation sequencing. Fasting serum lipids, apolipoprotein A-I [ApoA-I], apolipoprotein B [ApoB], and lipoprotein(a) (Lp(a)) were measured enzymatically. Levels of serum lipids were compared between genetically FH-positive (carriers of variants in LDLR, APOB, PCSK9 and LDLRAP1 genes) and FH-negative patients. Therapeutic response was assessed by achieving the LDL-C target level. Statistical analyses were conducted in SPSS (version 30.0). Genetically confirmed FH patients exhibited significantly higher levels of ApoB (p=0.001) compared with variant-negative individuals, while ApoA-I (p=0.413) and Lp(a) (p=0.421) levels did not differ significantly between groups. Patients with pathogenic FH-associated variants were less likely to reach target LDL-C levels after therapy than those without identified variants. This study demonstrates biochemical diversity in familial hypercholesterolemia associated with genetic background in the Serbian population. Pathogenic FH mutations were associated with higher ApoB levels, underscoring the importance of combining genetic testing with lipid profiling for precise diagnosis and management. Show less

Epithelial to mesenchymal transition (EMT) contributes to fibrosis associated pathologies including scarring of different ocular tissues. Recently targeting EMT is seen as an appropriate therapeutic approach for different fibrosis related eye diseases such as macular degeneration or glaucoma surgery related fibrosis. Nevertheless, for ocular surface diseases, target genes specific for particular cell type or condition are still undefined. This study aimed to expose the complex regulatory mechanisms that trigger EMT in human conjunctival epithelial (HCjE) cells. EMT was induced by prolonged treatment with two TGF-β isoforms, TGF-β1 and TGF-β2, and their combination. TGF-β1 showed the strongest potential for initiating EMT in HCjE cells, reflected on morphological changes, cell migration and the levels of mRNA expression of different epithelial (CDH1, OCLN, DSP) and mesenchymal (CDH2, FN1, VIM, SNAI1, ZEB2, TWIST1) marker genes. Co-treatment with the DNA demethylating agent 5-Azacytidine (5-AzaC) was capable of stopping the transition of HCjE cells towards a mesenchymal phenotype, based on morphological features, reduced cell mobility and mRNA and protein expression levels of epithelial and mesenchymal marker genes. An EMT qRT-PCR-based array revealed that EMT induced considerable alterations in gene expression, with downregulation of the majority of epithelial marker genes and upregulation of genes specific for the mesenchymal state. The major effect of 5-AzaC treatment was observed as a suppression of mesenchymal marker genes, suggesting the involvement of upstream negative regulator(s) whose promoter demethylation and subsequent expression will in turn promote EMT switch off. The expression level of miRNAs potentially important for EMT induction was determined using qRT-PCR-based array which pointed at members of miR-200 family as main regulators of EMT process in HCjE cells. 5-AzaC treatment induced increased expression of miR-200a, -200b, -200c and miR-141 towards the control level, indicating important role of DNA methylation in their regulation. The DNA methylation status of both miR-200 family clusters, analyzed with high-resolution melting (HRM) and bisulfite sequencing (Bis-Seq), revealed that TGF-β1-induced EMT was accompanied by increase in promoter CpG methylation of both miR-200 loci, which was reverted after 5-AzaC treatment. In conclusion, our results indicate that DNA demethylation of promoters of miR-200 loci is critically important for stopping and reverting the EMT in human conjunctival epithelial cells, suggesting the potential for the development of novel epigenetic-based therapeutic strategies for treating conjunctival conditions associated with EMT. Show less