👤 Güllü Özdemir

Mitochondrial dysfunction, oxidative stress, and neuroinflammation play a critical role in the occurrence and progression of Alzheimer's disease (AD). MicroRNAs (miRNAs) have been studied recently as potential therapeutic approaches for AD. In this study, we examined the function and underlying mechanism of microRNA-25802 (miR-25802), a newly discovered miRNA in an AD model. In order to evaluate the levels of oxidative stress, mitochondrial damage and neuroinflammation in neuroblastoma cells, four experimental groups were created: control group (neuroblastoma cells, SH-SY5Y), amyloid beta (Aβ)-induced neuroblastoma cells (SY5Y-Aβ), small extracellular vesicles (sEVs)-only group and miR-25802-loaded small extracellular vesicles (sEV-miR25802) administered group. Neuroinflammation, oxidative stress, mitochondrial damage, tau hyperphosphorylation, and Aβ accumulation were evaluated in Aβ-induced neuroblastoma cells. Oxidative stress was analyzed by measuring reactive oxygen species (ROS), malondialdehyde (MDA), lactate dehydrogenase (LDH), superoxide dismutase (SOD), and glutathione peroxidase 1 (GPX1). Inflammatory markers such as tumor necrosis factor-alpha (TNF-α), intercellular adhesion molecule 1 (ICAM1), and brain-derived neurotrophic factor (BDNF) mRNA levels, a neurotrophic factor, were evaluated by RT-qPCR. Neurofilament light chain (NfL), vascular endothelial growth factor-A (VEGF-A), macrophage migration inhibitory factor (MIF), monocyte chemoattractant protein-1 (MCP-1) and cytochrome c (Cyt-c), mitochondrial transcription factor A (TFAM), PTEN-induced kinase 1 (PINK1) and dynamin-1-like protein (DNM1L) protein levels were determined by ELISA. Mechanistically, sEV-miR25802 were shown to provide anti-inflammatory and neuroprotective effects by regulating neuroinflammation, mitochondrial dysfunction, and oxidative stress. These findings reveal the regulatory role of miR-25802 on neuroinflammation, mitochondrial damage, and oxidative stress and suggest that it may be a potential therapeutic target for AD. Show less

Studies have reported that the prevalence of aggression is higher in individuals with schizophrenia compared to the general population. Various factors, including genetic variations, contribute to the emergence of aggression in patients with schizophrenia. Among these, the monoamine oxidase A (MAOA) and brain-derived neurotrophic factor (BDNF) genes are considered key genetic factors potentially influencing aggressive behavior in schizophrenia. This study investigated the association of BDNF rs6265 and MAOA rs1465108 polymorphisms with aggression in schizophrenia. A total of 150 patients diagnosed with schizophrenia were included in the study. The MAOA rs1465108 and BDNF rs6265 polymorphisms were analyzed using the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) method. Aggression was evaluated using the Buss-Perry Aggression Questionnaire. Suicide risk, childhood trauma, and impulsivity which were related to aggression were evaluated using the Suicide Probability Scale, the Childhood Trauma Questionnaire, and the Barratt Impulsiveness Scale, respectively. Negative and positive symptoms of schizophrenia were assessed using the Scale for the Assessment of Negative Symptoms (SANS) and the Scale for the Assessment of Positive Symptoms (SAPS), respectively. No direct genotype associations were observed between aggression and the BDNF rs6265 and MAOA rs1465108 polymorphisms. However, impulsivity, SAPS, and SANS scores were significantly associated with aggression. These findings highlight that aggression in schizophrenia is primarily shaped by environmental and clinical factors rather than by BDNF or MAOA variants. Show less

In this study, we investigated the therapeutic potential of miR-206-3p delivered via small extracellular vesicles (sEVs) in an in vitro Alzheimer's disease model using SH-SY5Y human neuroblastoma cells treated with amyloid beta (Aβ). The sEV-miR-206-3p complexes were successfully loaded with miR-206-3p (∼0.001 copies per particle) without disrupting vesicle integrity or inducing cytotoxicity at the optimized concentration of 5 μg/mL. Aβ treatment significantly increased oxidative stress markers (ROS, MDA, LDH) and decreased antioxidant enzyme activity (SOD), while GPX1 showed an opposite trend. Furthermore, Aβ elevated proinflammatory gene expression (ICAM1, TNF-α) and reduced neuroprotective BDNF levels, induced mitochondrial dysfunction (increased Cyt-c, PINK1, DNM1L; decreased TFAM), impaired synaptic proteins (CPLX2, ROR1), and promoted tau phosphorylation and Aβ accumulation. Treatment with sEV-miR-206-3p effectively mitigated these alterations, reducing oxidative stress, suppressing neuroinflammatory responses, restoring mitochondrial function and synaptic protein levels, and attenuating tau and Aβ pathology. These findings demonstrate that miR-206-3p-loaded sEVs protect neuroblastoma cells from Aβ-induced neurodegenerative processes, highlighting their potential as a novel drug delivery system for neuroprotection. Show less

Dyslipidemia is a heterogeneous group of disorders that typically presents asymptomatically during childhood but increases the risk of atherosclerotic cardiovascular disease later in life. Understanding the genetic basis can provide valuable insights for early diagnosis and may support more tailored therapeutic approaches. This study aimed to investigate the genetic etiology of childhood-onset dyslipidemia and explore genotype-phenotype correlations. We retrospectively analyzed genetic data from 133 pediatric patients evaluated for suspected dyslipidemia between 2018 and 2023. Targeted next-generation sequencing (NGS) was performed using a panel covering 20 genes associated with lipid metabolism. Only pathogenic or likely pathogenic variants were included in the analysis. Pathogenic or likely pathogenic variants were identified in 17% of patients (n = 23). The most frequently affected gene was LDLR (74%), followed by significant variants in APOB, APOA5, LDLRAP1, and ALMS1. Three novel pathogenic variants were identified in this cohort: a splice-site variant in LDLRAP1 (c.231+2T>C) and two truncating variants in APOB (p.Tyr992Ter and p.Lys576Ter). Genotype-phenotype analysis revealed distinct impacts of variant types on lipid profiles. Notably, APOB variants were associated with both hypercholesterolemia and hypocholesterolemia. Our findings highlight the substantial contribution of genetic factors to childhood dyslipidemia and underscore the clinical utility of genetic testing in guiding diagnostic and therapeutic decisions. Show less

Advanced age is a well-recognized risk factor for atherosclerotic cardiovascular disease (ASCVD). Given the ongoing debate regarding the initiation of statin therapy in elderly individuals, identifying those with underlying coronary artery disease (CAD) who may benefit from lipid-lowering treatment is essential. This study aimed to identify predictors of CAD in statin-naïve adults aged ≥ 70 years with elevated low-density lipoprotein cholesterol (LDL-C), with particular emphasis on risk assessment, cumulative LDL-C burden, and lipoprotein(a) [Lp(a)] levels. The analysis included consecutive patients aged ≥ 70 years with LDL-C ≥ 160 mg/dL, available Lp(a) measurements, no prior history of ASCVD or diabetes, who underwent evaluation for CAD by coronary imaging or functional stress testing. Global ASCVD risk was estimated using the Systematic Coronary Risk Estimation 2-Older Persons (SCORE2-OP) and the Spanish Familial Hypercholesterolemia Cohort Study (SAFEHEART) risk scores. A total of 202 patients were included (mean age 76 years; 68.3% female). CAD was diagnosed in 30.7% of participants. In multivariable analysis, male sex (odds ratio [OR]: 2.109), Lp(a) level (OR: 1.012 per mg/dL), and cumulative LDL-C (OR: 1.155 per g/dL) were independently associated with CAD. The highest CAD prevalence was observed among individuals with cumulative LDL-C ≥ 14 g/dL and Lp(a) ≥ 50 mg/dL. While the SCORE2-OP algorithm failed to predict CAD, the SAFEHEART risk score was significantly associated with CAD. In statin-naïve elderly individuals with elevated LDL-C levels, male sex, cumulative LDL-C exposure, and high Lp(a) levels were independently associated with CAD. These findings underscore the potential utility of incorporating cumulative LDL-C and Lp(a) into risk stratification for older adults. Show less

Obesity is a complex disease resulting from the interaction of genetic and environmental factors. In this study, 414 single nucleotide polymorphism (SNPs) were analyzed in DNA samples obtained from 48 obese patients and 50 healthy controls of Turkish origin to identify genetic variants associated with obesity. Genotype frequency analysis revealed 18 variants significantly or near-significantly associated with obesity. Among these, rs12199580 (PNPLA1), rs34911341 (GHRL), and rs116843064 (ANGPTL4) emerged as novel candidate variants not previously reported in the context of obesity. Functional annotation analyses confirmed that most of the significant variants were located in exonic or regulatory regions, and the related genes were primarily involved in neuroendocrine control, lipid metabolism, and energy homeostasis. Pathway enrichment analysis indicated significant overrepresentation of pathways such as PPAR-alpha-regulated lipid metabolism, ghrelin synthesis and secretion, and cholesterol transport, which are all closely linked to obesity pathophysiology. Polygenic risk score models constructed from the significant SNPs demonstrated a markedly increased genetic risk burden when rare high-effect variants were included. In regression analyses adjusted for age, sex, and Body Mass Index (BMI), the variant rs17024258 in the GNAT2 gene maintained a statistically significant and independent association with BMI (P < .02), whereas most other variants lost significance after covariate adjustment. Furthermore, certain variants were found to exhibit markedly different allele frequencies in the Turkish cohort compared to global reference populations, highlighting potential population-specific genetic architecture. This study contributes to the identification of both previously known and novel genetic variants associated with obesity and underscores the importance of population-specific genomic data in understanding genetic predisposition to complex diseases such as obesity. Show less

Hypertrophic cardiomyopathy is a common genetic heart disease and up to 40%-60% of patients have mutations in cardiac sarcomere protein genes. This genetic diagnosis study aimed to detect pathogenic or likely pathogenic sarcomeric and non-sarcomeric gene mutations and to confirm a final molecular diagnosis in patients diagnosed with hypertrophic cardiomyopathy. A total of 392 patients with hypertrophic cardiomyopathy were included in this nationwide multicenter study conducted at 23 centers across Türkiye. All samples were analyzed with a 17-gene hypertrophic cardiomyopathy panel using next-generation sequencing technology. The gene panel includes ACTC1, DES, FLNC, GLA, LAMP2, MYBPC3, MYH7, MYL2, MYL3, PLN, PRKAG2, PTPN11, TNNC1, TNNI3, TNNT2, TPM1, and TTR genes. The next-generation sequencing panel identified positive genetic variants (variants of unknown significance, likely pathogenic or pathogenic) in 12 genes for 121 of 392 samples, including sarcomeric gene mutations in 30.4% (119/392) of samples tested, galactosidase alpha variants in 0.5% (2/392) of samples and TTR variant in 0.025% (1/392). The likely pathogenic or pathogenic variants identified in 69 (57.0%) of 121 positive samples yielded a confirmed molecular diagnosis. The diagnostic yield was 17.1% (15.8% for hypertrophic cardiomyopathy variants) for hypertrophic cardiomyopathy and hypertrophic cardiomyopathy phenocopies and 0.5% for Fabry disease. Our study showed that the distribution of genetic mutations, the prevalence of Fabry disease, and TTR amyloidosis in the Turkish population diagnosed with hypertrophic cardiomyopathy were similar to the other populations, but the percentage of sarcomeric gene mutations was slightly lower. Show less