DNA Hypomethylation of the MPO Gene in Peripheral Blood Leukocytes Is Associated with Cerebral Stroke in the Acute Phase

HSP90 Family Members, Their Regulators and Ischemic Stroke Risk: A Comprehensive Molecular-Genetics and Bioinformatics Analysis

BACKGROUND

Disruptions in proteostasis are recognized as key drivers in cerebro- and cardiovascular disease progression. Heat shock proteins (HSPs), essential for maintaining protein stability and cellular homeostasis, are pivotal in neuroperotection. Consequently, deepening the understanding the role of HSPs in ischemic stroke (IS) risk is crucial for identifying novel therapeutic targets and advancing neuroprotective strategies.

AIM

Our objective was to examine the potential correlation between single nucleotide polymorphisms (SNPs) in genes that encode members of the Heat shock protein 90 (HSP90), small heat shock proteins (HSPB), and heat shock factors (HSF) families, and the risk and clinical characteristics of IS.

METHODS

953 IS patients and 1265 controls from Central Russia were genotyped for nine SNPs in genes encoding HSP90AA1, HSFs, and HSPBs using the MassArray-4 system and probe-based polymerase chain reaction (PCR).

RESULTS

In smokers, SNP rs1133026 HSPB8 increased the risk of IS (risk allele A, odds ratio (OR) = 1.43, 95% Confidence Interval (CI) 1.02-2.02, p = 0.035), and rs556439 HSF2 increased the brain infarct size (risk allele A, p = 0.02). In non-smokers, SNPs rs4279640 HSF1 (protective allele T, OR = 0.58, 95% CI 0.37-0.92, p = 0.02) and rs4264324 HSP90AA1 (protective allele C, OR = 0.11, 95% CI 0.01-0.78, p = 0.001) lowered the risk of recurrent stroke; SNP rs7303637 HSPB8 increased the age of onset of IS (protective allele T, p = 0.04). In patients with body mass index (BMI) ≥25, SNPs rs556439 HSF2 (risk allele A, OR = 1.33, 95% CI 1.04-1.69, p = 0.02) and rs549302 HSF2 (risk allele G, OR = 1.34, 95% CI 1.02-1.75, p = 0.03) were linked to a higher risk of IS.

CONCLUSIONS

The primary molecular mechanisms through which the studied SNPs contribute to IS pathogenesis were found to be the regulation of cell death, inflammatory and oxidative stress responses.

Chaperones vs. oxidative stress in the pathobiology of ischemic stroke

As many proteins prioritize functionality over constancy of structure, a proteome is the shortest stave in the Liebig's barrel of cell sustainability. In this regard, both prokaryotes and eukaryotes possess abundant machinery supporting the quality of the proteome in healthy and stressful conditions. This machinery, namely chaperones, assists in folding, refolding, and the utilization of client proteins. The functions of chaperones are especially important for brain cells, which are highly sophisticated in terms of structural and functional organization. Molecular chaperones are known to exert beneficial effects in many brain diseases including one of the most threatening and widespread brain pathologies, ischemic stroke. However, whether and how they exert the antioxidant defense in stroke remains unclear. Herein, we discuss the chaperones shown to fight oxidative stress and the mechanisms of their antioxidant action. In ischemic stroke, during intense production of free radicals, molecular chaperones preserve the proteome by interacting with oxidized proteins, regulating imbalanced mitochondrial function, and directly fighting oxidative stress. For instance, cells recruit Hsp60 and Hsp70 to provide proper folding of newly synthesized proteins-these factors are required for early ischemic response and to refold damaged polypeptides. Additionally, Hsp70 upregulates some dedicated antioxidant pathways such as FOXO3 signaling. Small HSPs decrease oxidative stress via attenuation of mitochondrial function through their involvement in the regulation of Nrf- (Hsp22), Akt and Hippo (Hsp27) signaling pathways as well as mitophagy (Hsp27, Hsp22). A similar function has also been proposed for the Sigma-1 receptor, contributing to the regulation of mitochondrial function. Some chaperones can prevent excessive formation of reactive oxygen species whereas Hsp90 is suggested to be responsible for pro-oxidant effects in ischemic stroke. Finally, heat-resistant obscure proteins (Hero) are able to shield client proteins, thus preventing their possible over oxidation.

Polymorphism in Genes Encoding HSP40 Family Proteins is Associated with Ischemic Stroke Risk and Brain Infarct Size: A Pilot Study

BACKGROUND

Heat shock proteins (HSPs) play a critical role in the molecular mechanisms of ischemic stroke (IS). A possible role for HSP40 family proteins in atherosclerosis progression has already been revealed; however, to date, molecular genetic studies on the involvement of genes encoding proteins of the HSP40 family in IS have not yet been carried out.

AIM

We sought to determine whether nine single nucleotide polymorphisms (SNPs) in genes encoding HSP40 family proteins (DNAJB1, DNAJB2, DNAJA1, DNAJA2, DNAJA3 and DNAJC7) are associated with the risk and clinical features of IS.

METHODS

Using TaqMan-based polymerase chain reaction (PCR) and the MassArray-4 system, DNA samples of 2551 Russians - 1306 IS patients and 1245 healthy individuals - were genotyped.

RESULTS

SNP rs2034598 DNAJA2 decreased the risk of IS exclusively in male patients (odds ratio = 0.81, 95% confidence interval 0.78-0.98, p = 0.028); rs7189628 DNAJA2 increased the brain infarct size (p = 0.04); and rs6500605 DNAJA3 lowered the age of onset of IS (p = 0.03). SNPs rs10448231 DNAJA1, rs7189628 DNAJA2, rs4926222 DNAJB1 and rs2034598 DNAJA2 were involved in the strongest epistatic interactions linked to IS; SNP rs10448231 DNAJA1 is characterised by the most essential mono-effect (2.96% of IS entropy); all of the top SNP-SNP interaction models included the pairwise combination rs7189628 DNAJA2×rs4926222 DNAJB1, which was found to be a key factor determining susceptibility to IS. In interactions with the studied SNPs, smoking was found to have multidirectional effects (synergism, antagonism or additive effect) and the strongest mono-effect (3.47% of IS entropy), exceeding the mono-effects of rs6500605 DNAJA3, rs10448231 DNAJA1, rs2034598 DNAJA2, rs7189628 DNAJA2 and rs4926222 DNAJB1, involved in the best G×E models and determining 0.03%-0.73% of IS entropy.

CONCLUSIONS

We are the first to discover polymorphisms in genes encoding HSP40 family proteins as a major risk factor for IS and its clinical manifestations. The comprehensive bioinformatics analysis revealed molecular mechanisms, underscoring their significance in the pathogenesis of IS, primarily reflecting the regulation of heat stress, proteostasis and cellular signalling.

C11orf58 (Hero20) Gene Polymorphism: Contribution to Ischemic Stroke Risk and Interactions with Other Heat-Resistant Obscure Chaperones

Background: Recently identified Hero proteins, which possess chaperone-like functions, are promising candidates for research into atherosclerosis-related diseases, including ischemic stroke (IS). Methods: 2204 Russian subjects (917 IS patients and 1287 controls) were genotyped for fifteen common SNPs in Hero20 gene C11orf58 using probe-based PCR and the MassArray-4 system. Results: Six C11orf58 SNPs were significantly associated with an increased risk of IS in the overall group (OG) and significantly modified by smoking (SMK) and low fruit/vegetable intake (LFVI): rs10766342 (effect allele (EA) A; P(OG = 0.02; SMK = 0.009; LFVI = 0.04)), rs11024032 (EA T; P(OG = 0.01; SMK = 0.01; LFVI = 0.036)), rs11826990 (EA G; P(OG = 0.007; SMK = 0.004; LFVI = 0.03)), rs3203295 (EA C; P(OG = 0.016; SMK = 0.01; LFVI = 0.04)), rs10832676 (EA G; P(OG = 0.006; SMK = 0.002; LFVI = 0.01)), rs4757429 (EA T; P(OG = 0.02; SMK = 0.04; LFVI = 0.04)). The top ten intergenic interactions of Hero genes (two-, three-, and four-locus models) involved exclusively polymorphic loci of C11orf58 and C19orf53 and were characterized by synergic and additive (independent) effects between SNPs. Conclusions: Thus, C11orf58 gene polymorphism represents a major risk factor for IS. Bioinformatic analysis showed the involvement of C11orf58 SNPs in molecular mechanisms of IS mediated by their role in the regulation of redox homeostasis, inflammation, vascular remodeling, apoptosis, vasculogenesis, neurogenesis, lipid metabolism, proteostasis, hypoxia, cell signaling, and stress response. In terms of intergenic interactions, C11orf58 interacts most closely with C19orf53.

MicroRNA-199a-5p attenuates blood-brain barrier disruption following ischemic stroke by regulating PI3K/Akt signaling pathway

OBJECTIVE

To explore whether miR-199a-5p regulated BBB integrity through PI3K/Akt pathway after ischemia stroke.

METHODS

Adult male Sprague-Dawley rats with permanent middle cerebral artery occlusion(MCAO) were used in experiment. The Ludmila Belayev 12-point scoring was used to measure the neurological function of MCAO rats. The Evans Blue Stain, immunofluorescence staining, western-blotting and RT-PCR were performed to evaluate the effects of miR-199a-5p mimic on BBB integrity in rats following MCAO.

RESULTS

The result suggested that miR-199a-5p mimic treatment possessed the potential to boost proprioception and motor activity of MCAO rats. MiR-199a-5p decreased the expression of PIK3R2 after MCAO, activated Akt signaling pathway, and increased the expression of Claudin-5 and VEGF in the ischemic penumbra. Furthermore, miR-199a-5p alleviated inflammation after cerebral ischemia. BBB leakage and neurocyte apoptosis were cut down in MCAO rats treated with miR-199a-5p mimic.

CONCLUSIONS

MiR-199a-5p mimic decreased the expression of PIK3R2 and activated Akt signaling pathway after ischemia stroke, reduced the expression of inflammatory cytokines, and attenuated BBB disruption after ischemic stroke.

A Comprehensive Genetic and Bioinformatic Analysis Provides Evidence for the Engagement of COVID-19 GWAS-Significant Loci in the Molecular Mechanisms of Coronary Artery Disease and Stroke

Cardiovascular diseases (CVDs) significantly exacerbate the severity and mortality of COVID-19. We aimed to investigate whether GWAS-significant SNPs correlate with CVDs in severe COVID-19 patients. DNA samples from 199 patients with severe COVID-19 hospitalized in intensive care units were genotyped using probe-based PCR for 10 GWAS SNPs previously implicated in severe COVID-19 outcomes. SNPs rs17713054 SLC6A20-LZTFL1 (risk allele A, OR = 2.14, 95% CI 1.06–4.36, p = 0.03), rs12610495 DPP9 (risk allele G, OR = 1.69, 95% CI 1.02–2.81, p = 0.04), and rs7949972 ELF5 (risk allele T, OR = 2.57, 95% CI 1.43–4.61, p = 0.0009) were associated with increased risk of coronary artery disease (CAD). SNPs rs7949972 ELF5 (OR = 2.67, 95% CI 1.38–5.19, p = 0.003) and rs61882275 ELF5 (risk allele A, OR = 1.98, 95% CI 1.14–3.45, p = 0.01) were linked to a higher risk of cerebral stroke (CS). No associations were observed with AH. Bioinformatics analysis revealed the involvement of GWAS-significant loci in atherosclerosis, inflammation, oxidative stress, angiogenesis, and apoptosis, which provides evidence of their role in the molecular mechanisms of CVDs. This study provides novel insights into the associations between GWAS-identified SNPs and the risk of CAD and CS.

Obesity and Environmental Risk Factors Significantly Modify the Association between Ischemic Stroke and the Hero Chaperone C19orf53

The unique chaperone-like properties of C19orf53, discovered in 2020 as a "hero" protein, make it an intriguing subject for research in relation to ischemic stroke (IS). Our pilot study aimed to investigate whether C19orf53 SNPs are associated with IS. DNA samples from 2138 Russian subjects (947 IS and 1308 controls) were genotyped for 7 C19orf53 SNPs using probe-based PCR. Dominant (D), recessive (R), and log-additive (A) regression models in relation to the effect alleles (EA) were used to interpret associations. An increased risk of IS was associated with rs10104 (EA G; Pbonf(R) = 0.0009; Pbonf(A) = 0.0004), rs11666524 (EA A; Pbonf(R) = 0.003; Pbonf(A) = 0.02), rs346158 (EA C; Pbonf(R) = 0.006; Pbonf(A) = 0.045), and rs2277947 (EA A; Pbonf(R) = 0.002; Pbonf(A) = 0.01) in patients with obesity; with rs11666524 (EA A; Pbonf(R) = 0.02), rs346157 (EA G; Pbonf(R) = 0.036), rs346158 (EA C; Pbonf(R) = 0.005), and rs2277947 (EA A; Pbonf(R) = 0.02) in patients with low fruit and vegetable intake; and with rs10104 (EA G; Pbonf(R) = 0.03) and rs11666524 (EA A; Pbonf(R) = 0.048) in patients with low physical activity. In conclusion, our pilot study provides comprehensive genetic and bioinformatic evidence of the involvement of C19orf53 in IS risk.

GWAS-significant loci and severe COVID-19: analysis of associations, link with thromboinflammation syndrome, gene-gene, and gene-environmental interactions

Objective

The aim of this study was to replicate associations of GWAS-significant loci with severe COVID-19 in the population of Central Russia, to investigate associations of the SNPs with thromboinflammation parameters, to analyze gene-gene and gene-environmental interactions.

Materials and Methods

DNA samples from 798 unrelated Caucasian subjects from Central Russia (199 hospitalized COVID-19 patients and 599 controls with a mild or asymptomatic course of COVID-19) were genotyped using probe-based polymerase chain reaction for 10 GWAS-significant SNPs: rs143334143 CCHCR1, rs111837807 CCHCR1, rs17078346 SLC6A20-LLZTFL1, rs17713054 SLC6A20-LLZTFL1, rs7949972 ELF5, rs61882275 ELF5, rs12585036 ATP11A, rs67579710 THBS3, THBS3-AS1, rs12610495 DPP9, rs9636867 IFNAR2.

Results

SNP rs17713054 SLC6A20-LZTFL1 was associated with increased risk of severe COVID-19 in the entire group (risk allele A, OR = 1.78, 95% CI = 1.22-2.6, p = 0.003), obese individuals (OR = 2.31, 95% CI = 1.52-3.5, p = 0.0002, (p bonf = 0.0004)), patients with low fruit and vegetable intake (OR = 1.72, 95% CI = 1.15-2.58, p = 0.01, (p bonf = 0.02)), low physical activity (OR = 1.93, 95% CI = 1.26-2.94, p = 0.0035, (p bonf = 0.007)), and nonsmokers (OR = 1.65, 95% CI = 1.11-2.46, p = 0.02). This SNP correlated with increased BMI (p = 0.006) and worsened thrombodynamic parameters (maximum optical density of the formed clot, D (p = 0.02), delayed appearance of spontaneous clots, Tsp (p = 0.02), clot size 30 min after coagulation activation, CS (p = 0.036)). SNP rs17078346 SLC6A20-LZTFL1 was linked with increased BMI (p = 0.01) and severe COVID-19 in obese individuals (risk allele C, OR = 1.72, 95% CI = 1.15-2.58, p = 0.01, (p bonf = 0.02)). SNP rs12610495 DPP9 was associated with increased BMI (p = 0.01), severe COVID-19 in obese patients (risk allele G, OR = 1.48, 95% CI = 1.09-2.01, p = 0.01, (p bonf = 0.02)), and worsened thrombodynamic parameters (time to the start of clot growth, Tlag (p = 0.01)). For rs7949972 ELF5, a protective effect against severe COVID-19 was observed in non-obese patients (effect allele T, OR = 0.67, 95% CI = 0.47-0.95, p = 0.02, (p bonf = 0.04)), improving thrombodynamic parameters (CS (p = 0.02), stationary spatial clot growth rates, Vst (p = 0.02)). Finally, rs12585036 ATP11A exhibited a protective effect against severe COVID-19 in males (protective allele A, OR = 0.51, 95% CI = 0.32-0.83, p = 0.004). SNPs rs67579710 THBS3, THBS3-AS1, rs17713054 SLC6A20-LZTFL1, rs7949972 ELF5, rs9636867 IFNAR2-were involved in two or more of the most significant G×G interactions (p perm ≤ 0.01). The pairwise combination rs67579710 THBS3, THBS3-AS1 × rs17713054 SLC6A20-LZTFL1 was a priority in determining susceptibility to severe COVID-19 (it was included in four of the top five most significant SNP-SNP interaction models).

Conclusion

Overall, this study represents a comprehensive molecular-genetic and bioinformatics analysis of the involvement of GWAS-significant loci in the molecular mechanisms of severe COVID-19, gene-gene and gene-environmental interactions, and provides evidence of their relationship with thromboinflammation parameters in patients hospitalized in intensive care units.

Polymorphism of SERF2, the gene encoding a heat-resistant obscure (Hero) protein with chaperone activity, is a novel link in ischemic stroke

Background

Ischemic stroke (IS) is one of the most serious cardiovascular events associated with high risk of death or disability. The growing body of evidence highlights molecular chaperones as especially important players in the pathogenesis of the disease. Since six small proteins called "Hero" have been recently identified as a novel class of chaperones we aimed to evaluate whether SNP rs4644832 in SERF2 gene encoding the member of Hero-proteins, is associated with the risk of IS.

Methods

A total of 1929 unrelated Russians (861 patients with IS and 1068 healthy individuals) from Central Russia were recruited into the study. Genotyping was done using a probe-based PCR approach. Statistical analysis was carried out in the whole group and stratified by age, gender and smoking status.

Results

Analysis of the link between rs4644832 SERF2 and IS showed that G allele is the risk factor of IS only in females (OR=1.29, 95%CI 1.02-1.64, Padj=0.035). In addition, the analysis of associations of rs4644832 SERF2 and IS depending on the smoking status revealed that this genetic variant is associated with an increased risk of IS exclusively in non-smoking individuals (OR=1.26, 95%CI 1.01-1.56, P = 0.041).

Discussion

Sex- and smoking interactions between rs4644832 polymorphism and IS may be related to the impact of tobacco components metabolism and sex hormones on SERF2 expression.

Conclusion

The present study reveals the novel genetic association between rs4644832 polymorphism and the risk of IS suggesting that SERF2, the part of the protein quality control system, contributes to the pathogenesis of the disease.

Association between HSPA8 Gene Variants and Ischemic Stroke: A Pilot Study Providing Additional Evidence for the Role of Heat Shock Proteins in Disease Pathogenesis

HSPA8 is involved in many stroke-associated cellular processes, playing a pivotal role in the protein quality control system. Here we report the results of the pilot study aimed at determining whether HSPA8 SNPs are linked to the risk of ischemic stroke (IS). DNA samples from 2139 Russians (888 IS patients and 1251 healthy controls) were genotyped for tagSNPs (rs1461496, rs10892958, and rs1136141) in the HSPA8 gene using probe-based PCR. SNP rs10892958 of HSPA8 was associated with an increased risk (risk allele G) of IS in smokers (OR = 1.37; 95% CI = 1.07-1.77; p = 0.01) and patients with low fruit and vegetable consumption (OR = 1.36; 95% CI = 1.14-1.63; p = 0.002). SNP rs1136141 of HSPA8 was also associated with an increased risk of IS (risk allele A) exclusively in smokers (OR = 1.68; 95% CI = 1.23-2.28; p = 0.0007) and in patients with a low fruit and vegetable intake (OR = 1.29; 95% CI = 1.05-1.60; p = 0.04). Sex-stratified analysis revealed an association of rs10892958 HSPA8 with an increased risk of IS in males (risk allele G; OR = 1.30; 95% CI = 1.05-1.61; p = 0.01). Thus, SNPs rs10892958 and rs1136141 in the HSPA8 gene represent novel genetic markers of IS.

SERPINE1 mRNA Binding Protein 1 Is Associated with Ischemic Stroke Risk: A Comprehensive Molecular-Genetic and Bioinformatics Analysis of SERBP1 SNPs

The SERBP1 gene is a well-known regulator of SERPINE1 mRNA stability and progesterone signaling. However, the chaperone-like properties of SERBP1 have recently been discovered. The present pilot study investigated whether SERBP1 SNPs are associated with the risk and clinical manifestations of ischemic stroke (IS). DNA samples from 2060 unrelated Russian subjects (869 IS patients and 1191 healthy controls) were genotyped for 5 common SNPs-rs4655707, rs1058074, rs12561767, rs12566098, and rs6702742 SERBP1-using probe-based PCR. The association of SNP rs12566098 with an increased risk of IS (risk allele C; p = 0.001) was observed regardless of gender or physical activity level and was modified by smoking, fruit and vegetable intake, and body mass index. SNP rs1058074 (risk allele C) was associated with an increased risk of IS exclusively in women (p = 0.02), non-smokers (p = 0.003), patients with low physical activity (p = 0.04), patients with low fruit and vegetable consumption (p = 0.04), and BMI ≥25 (p = 0.007). SNPs rs1058074 (p = 0.04), rs12561767 (p = 0.01), rs12566098 (p = 0.02), rs6702742 (p = 0.036), and rs4655707 (p = 0.04) were associated with shortening of activated partial thromboplastin time. Thus, SERBP1 SNPs represent novel genetic markers of IS. Further studies are required to confirm the relationship between SERBP1 polymorphism and IS risk.

The Impact of Genetic Polymorphisms in Glutamate-Cysteine Ligase, a Key Enzyme of Glutathione Biosynthesis, on Ischemic Stroke Risk and Brain Infarct Size

The purpose of this pilot study was to explore whether polymorphisms in genes encoding the catalytic (GCLC) and modifier (GCLM) subunits of glutamate-cysteine ligase, a rate-limiting enzyme in glutathione synthesis, play a role in the development of ischemic stroke (IS) and the extent of brain damage. A total of 1288 unrelated Russians, including 600 IS patients and 688 age- and sex-matched healthy subjects, were enrolled for the study. Nine common single nucleotide polymorphisms (SNPs) of the GCLC and GCLM genes were genotyped using the MassArray-4 system. SNP rs2301022 of GCLM was strongly associated with a decreased risk of ischemic stroke regardless of sex and age (OR = 0.39, 95%CI 0.24−0.62, p < 0.0001). Two common haplotypes of GCLM possessed protective effects against ischemic stroke risk (p < 0.01), but exclusively in nonsmoker patients. Infarct size was increased by polymorphisms rs636933 and rs761142 of GCLC. The mbmdr method enabled identifying epistatic interactions of GCLC and GCLM gene polymorphisms with known IS susceptibility genes that, along with environmental risk factors, jointly contribute to the disease risk and brain infarct size. Understanding the impact of genes and environmental factors on glutathione metabolism will allow the development of effective strategies for the treatment of ischemic stroke and disease prevention.

Association of CYP26C1 Promoter Hypomethylation with Small Vessel Occlusion in Korean Subjects

The risk factors for stroke, a fatal disease, include type two diabetes, hypertension, and genetic influences. Small vessel occlusion (SVO) can be affected by epigenetic alterations, but an association between SVO and the methylation of cytochrome P450 family 26 subfamily C member 1 (CYP26C1) has not been identified. In this study, we measured the level of DNA methylation in the CYP26C1 promoter and the 5′ untranslated region of 115 normal subjects and 56 patients with SVO in Korea. The DNA methylation level of each subject was measured by bisulfite amplicon sequencing, and statistical analysis was performed using the general linear model or Pearson’s correlation. The average level of DNA methylation was markedly lower in patients with SVO than in normal subjects (20.4% vs. 17.5%). We found that the methylation of CYP26C1 has a significant positive correlation with blood parameters including white blood cells, hematocrit, lactate dehydrogenase, and Na+ in subjects with SVO. We predicted that binding of RXR-α and RAR-β might be affected by CYP26C1 methylation at CpG sites −246–237 and −294–285. These findings suggest that CYP26C1 methylation in the promoter region may be a predictor of SVO.