HDAC9 Polymorphisms Predict Susceptibility, Severity, and Short-Term Outcome of Large Artery Atherosclerotic Stroke in Chinese Population

Genetics of ischemic stroke functional outcome

Ischemic stroke, which accounts for 87% of cerebrovascular accidents, is responsible for massive global burden both in terms of economic cost and personal hardship. Many stroke survivors face long-term disability-a phenotype associated with an increasing number of genetic variants. While clinical variables such as stroke severity greatly impact recovery, genetic polymorphisms linked to functional outcome may offer physicians a unique opportunity to deliver personalized care based on their patient's genetic makeup, leading to improved outcomes. A comprehensive catalogue of the variants at play is required for such an approach. In this review, we compile and describe the polymorphisms associated with outcome scores such as modified Rankin Scale and Barthel Index. Our search identified 74 known genetic polymorphisms spread across 48 features associated with various poststroke disability metrics. The known variants span diverse biological systems and are related to inflammation, vascular homeostasis, growth factors, metabolism, the p53 regulatory pathway, and mitochondrial variation. Understanding how these variants influence functional outcome may be helpful in maximizing poststroke recovery.

The roles of MMP8/MMP10 polymorphisms in ischemic stroke susceptibility

BACKGROUND

Ischemic stroke (IS), a multifactorial and polygenic disease, is the most common cause of death. This study aimed to determine the roles of MMP8/MMP10 polymorphisms in IS susceptibility in the Chinese Han population.

METHODS

MMP8 rs1940475 and rs3765620, and MMP10 rs17860949 from 700 IS patients and 700 controls were genotyped by the MassARRAY iPLEX platform. The impact of polymorphisms on IS risk was evaluated by logistic regression analysis.

RESULTS

Our study indicated that rs17860949 in MMP10 was significantly associated with a reduced risk of IS (OR = 0.632, p = .002). Precisely, stratification analysis showed that rs17860949 was relate to a decreased susceptibility to IS in patients aged > 55 years (OR = 0.472, p < .001), males (OR = 0.632, p = .012), nonsmokers (OR = 0.610, p = .017), and nondrinkers (OR = 0.559, p = .006). All these significant findings were verified by false-positive report probability test. Furthermore, GG genotype and AG genotype in MMP8 rs3765620 polymorphism were related to a reduced triglycerides concentration (p = .018).

CONCLUSION

Our study suggests that rs17860949 in MMP10 may play a protective role in IS in the Chinese Han population.

Epigenetic mechanisms and potential therapeutic targets in stroke

Accumulating evidence indicates a central role for epigenetic modifications in the progression of stroke pathology. These epigenetic mechanisms are involved in complex and dynamic processes that modulate post-stroke gene expression, cellular injury response, motor function, and cognitive ability. Despite decades of research, stroke continues to be classified as a leading cause of death and disability worldwide with limited clinical interventions. Thus, technological advances in the field of epigenetics may provide innovative targets to develop new stroke therapies. This review presents the evidence on the impact of epigenomic readers, writers, and erasers in both ischemic and hemorrhagic stroke pathophysiology. We specifically explore the role of DNA methylation, DNA hydroxymethylation, histone modifications, and epigenomic regulation by long non-coding RNAs in modulating gene expression and functional outcome after stroke. Furthermore, we highlight promising pharmacological approaches and biomarkers in relation to epigenetics for translational therapeutic applications.

Sex-Dependent Role of Adipose Tissue HDAC9 in Diet-Induced Obesity and Metabolic Dysfunction

Obesity is a major risk factor for both metabolic and cardiovascular disease. We reported that, in obese male mice, histone deacetylase 9 (HDAC9) is upregulated in adipose tissues, and global deletion of HDAC9 protected against high fat diet (HFD)-induced obesity and metabolic disease. Here, we investigated the impact of adipocyte-specific HDAC9 gene deletion on diet-induced obesity in male and female mice. The HDAC9 gene expression was increased in adipose tissues of obese male and female mice and HDAC9 expression correlated positively with body mass index in humans. Interestingly, female, but not male, adipocyte-specific HDAC9 KO mice on HFD exhibited reduced body weight and visceral adipose tissue mass, adipocyte hypertrophy, and improved insulin sensitivity, glucose tolerance and adipogenic differentiation gene expression. Furthermore, adipocyte-specific HDAC9 gene deletion in female mice improved metabolic health as assessed by whole body energy expenditure, oxygen consumption, and adaptive thermogenesis. Mechanistically, compared to female mice, HFD-fed male mice exhibited preferential HDAC9 expression in the stromovascular fraction, which may have offset the impact of adipocyte-specific HDAC9 gene deletion in male mice. These results suggest that HDAC9 expressed in adipocytes is detrimental to obesity in female mice and provides novel evidence of sex-related differences in HDAC9 cellular expression and contribution to obesity-related metabolic disease.

Association of DNA Methylation in Blood Pressure-Related Genes With Ischemic Stroke Risk and Prognosis

Background

A genome-wide association study identified 12 genetic loci influencing blood pressure and implicated a role of DNA methylation. However, the relationship between methylation and ischemic stroke has not yet been clarified. We conducted a large-sample sequencing study to identify blood leukocyte DNA methylations as novel biomarkers for ischemic stroke risk and prognosis based on previously identified genetic loci.

Methods

Methylation levels of 17 genes were measured by sequencing in 271 ischemic stroke cases and 323 controls, and the significant associations were validated in another independent sample of 852 cases and 925 controls. The associations between methylation levels and ischemic stroke risk and prognosis were evaluated.

Results

Methylation of AMH, C17orf82, HDAC9, IGFBP3, LRRC10B, PDE3A, PRDM6, SYT7 and TBX2 was significantly associated with ischemic stroke. Compared to participants without any hypomethylated targets, the odds ratio (OR) (95% confidence interval, CI) for those with 9 hypomethylated genes was 1.41 (1.33–1.51) for ischemic stroke. Adding methylation levels of the 9 genes to the basic model of traditional risk factors significantly improved the risk stratification for ischemic stroke. Associations between AMH, HDAC9, IGFBP3, PDE3A and PRDM6 gene methylation and modified Rankin Scale scores were significant after adjustment for covariates. Lower methylation levels of AMH, C17orf82, PRDM6 and TBX2 were significantly associated with increased 3-month mortality. Compared to patients without any hypomethylated targets, the OR (95% CI) for those with 4 hypomethylated targets was 1.12 (1.08–1.15) for 3-month mortality (P = 2.28 × 10−10).

Conclusion

The present study identified blood leukocyte DNA methylations as potential factors affecting ischemic stroke risk and prognosis among Han Chinese individuals.

Autophagy and apoptosis cascade: which is more prominent in neuronal death?

Autophagy and apoptosis are two crucial self-destructive processes that maintain cellular homeostasis, which are characterized by their morphology and regulated through signal transduction mechanisms. These pathways determine the fate of cellular organelle and protein involved in human health and disease such as neurodegeneration, cancer, and cardiovascular disease. Cell death pathways share common molecular mechanisms, such as mitochondrial dysfunction, oxidative stress, calcium ion concentration, reactive oxygen species, and endoplasmic reticulum stress. Some key signaling molecules such as p53 and VEGF mediated angiogenic pathway exhibit cellular and molecular responses resulting in the triggering of apoptotic and autophagic pathways. Herein, based on previous studies, we describe the intricate relation between cell death pathways through their common genes and the role of various stress-causing agents. Further, extensive research on autophagy and apoptotic machinery excavates the implementation of selective biomarkers, for instance, mTOR, Bcl-2, BH3 family members, caspases, AMPK, PI3K/Akt/GSK3β, and p38/JNK/MAPK, in the pathogenesis and progression of neurodegenerative diseases. This molecular phenomenon will lead to the discovery of possible therapeutic biomolecules as a pharmacological intervention that are involved in the modulation of apoptosis and autophagy pathways. Moreover, we describe the potential role of micro-RNAs, long non-coding RNAs, and biomolecules as therapeutic agents that regulate cell death machinery to treat neurodegenerative diseases. Mounting evidence demonstrated that under stress conditions, such as calcium efflux, endoplasmic reticulum stress, the ubiquitin-proteasome system, and oxidative stress intermediate molecules, namely p53 and VEGF, activate and cause cell death. Further, activation of p53 and VEGF cause alteration in gene expression and dysregulated signaling pathways through the involvement of signaling molecules, namely mTOR, Bcl-2, BH3, AMPK, MAPK, JNK, and PI3K/Akt, and caspases. Alteration in gene expression and signaling cascades cause neurotoxicity and misfolded protein aggregates, which are characteristics features of neurodegenerative diseases. Excessive neurotoxicity and misfolded protein aggregates lead to neuronal cell death by activating death pathways like autophagy and apoptosis. However, autophagy has a dual role in the apoptosis pathways, i.e., activation and inhibition of the apoptosis signaling. Further, micro-RNAs and LncRNAs act as pharmacological regulators of autophagy and apoptosis cascade, whereas, natural compounds and chemical compounds act as pharmacological inhibitors that rescue neuronal cell death through inhibition of apoptosis and autophagic cell death.

Association between Histone Deacetylase 9 Gene Polymorphism and Stroke in Chinese Han Population

Objective

To explore the correlation between the polymorphism of histone deacetylase 9 gene (rs1060499865, rs723296, rs957960) and ischemic stroke (IS) in Chinese Han population in Dali region.

Methods

This study included 155 IS patients and 128 healthy physical examinees. TaqMan-polymerase chain reaction technology and multivariate logistic regression were performed.

Results

In the case group, there was no polymorphism of rs1060499865 observed in the two groups; whereas on the rs723296 locus the frequencies of C allele and TC genotype were significantly higher than that in the control group, alleles C and T were associated with a 2.158-fold increase in IS risk, and genotypes TC and TT were associated with a 2.269-fold increase in IS risk. The locus rs957960 exhibited no significant difference between the two groups.

Conclusion

An association between rs723296 and the risk of IS was found in the Chinese Han population in Dali region. No significant association was found between rs1060499865, rs957960 and IS in the Chinese Han population in Dali region.

Updating a Strategy for Histone Deacetylases and Its Inhibitors in the Potential Treatment of Cerebral Ischemic Stroke

BACKGROUND

Cerebral ischemic stroke is one of the severe diseases with a pathological condition that leads to nerve cell dysfunction with seldom available therapy options. Currently, there are few proven effective treatments available for improving cerebral ischemic stroke outcome. However, recently, there is increasing evidence that inhibition of histone deacetylase (HDAC) activity exerts a strong protective effect in in vivo and vitro models of ischemic stroke. Review Summary. HDAC is a posttranslational modification that is negatively regulated by histone acetyltransferase (HATS) and histone deacetylase. Based on function and DNA sequence similarity, histone deacetylases (HDACs) are organized into four different subclasses (I-IV). Modifications of histones play a crucial role in cerebral ischemic affair development after translation by modulating disrupted acetylation homeostasis. HDAC inhibitors (HDACi) mainly exert neuroprotective effects by enhancing histone and nonhistone acetylation levels and enhancing gene expression and protein modification functions. This article reviews HDAC and its inhibitors, hoping to find meaningful therapeutic targets.

CONCLUSIONS

HDAC may be a new biological target for cerebral ischemic stroke. Future drug development targeting HDAC may make it a potentially effective anticerebral ischemic stroke drug.

TNFRSF11B polymorphisms predict poor outcome after large artery atherosclerosis stroke

Osteoprotegerin is involved in the progression of atherosclerosis. This study aimed to determine whether TNFRSF11B polymorphisms are associated with prognosis of large artery atherosclerosis (LAA) stroke. Three TNFRSF11B polymorphisms (rs2073617, rs2073618 and rs3134069) were genotyped in 1010 patients with LAA stroke. Short-term outcome was evaluated using the modified Rankin Scale score at 3-month after stroke onset. Long-term outcome was assessed using the stroke recurrence. We found that rs2073617G was associated with an increased risk of poor outcome of LAA stroke (additive model: odds ratio (OR) = 1.35, 95% confidence interval (CI) = 1.06-1.73). This association was also observed in rs3134069C (additive model: OR = 1.53, 95% CI = 1.10-2.12). Furthermore, when we combined these two polymorphisms according to the numbers of risk alleles (rs2073617G and rs3134069C), we found that the patients with 3-4 risk alleles were statistically significantly associated with an increased risk of poor outcome of LAA stroke (OR = 1.90, 95% CI = 1.10-3.28) compared with 0-2 risk alleles, and this increased risk was more evident among those with hypertension (OR = 2.02, 95% CI = 1.04-3.91), those without diabetes (OR = 2.02, 95% CI = 1.02-4.01) and those with smoking (OR = 2.43, 95% CI = 1.09-5.42). In silico analysis showed that rs2073617 and rs3134069 are located in various histone modification marked regions, DNase I hypersensitive sites and can change the binding of regulatory motifs. Moreover, rs2073617 is also located in the binding site of transcription factors. Our findings suggested that TNFRSF11B polymorphisms may be associated with an increased risk of short-term poor outcome of LAA stroke.

Ischemic Stroke and Genetic Variants: In Search of Association with Severity and Recurrence in a Brazilian Population

OBJECTIVE

The aim of this study was to investigate the relationship between genetic variants in candidate genes and clinical severity and prognosis (recurrence) of ischemic stroke (IS) in a Brazilian population.

METHODS

This was a retrospective study based on clinical and demographic data retrieved from the JOINVASC cohort-Epidemiological Study on Cerebrovascular Diseases in Joinville and on respective DNA samples available at the Joinville Stroke Biobank, over the period 2010-2015. Four hundred and thirty-five subjects were included. Patients were divided into large artery atherosclerosis (195 cases) and cardioembolic IS (240 cases) subgroups according to Trial of Org 10172 in the Acute Stroke Treatment standards. The severity of the event was established from the score obtained using the National Institutes of Health Stroke Scale. The genotypic and allelic frequencies of each variant were acquired by Real-Time Polymerase Chain Reaction. The codominance model was considered for the analysis of the genotypes' influence.

RESULTS

There was no association between clinical severity and recurrence with variants rs2383207 (CDKN2B-AS1) for atherothrombotic IS and variants rs879324 (ZFHX3), rs966221 (PDE4D), and rs152312 (PDE4D) for cardioembolic IS. The variants rs1396476, rs2910829, rs6843082, and rs2107595 were not in Hardy-Weinberg equilibrium in the evaluated population.

CONCLUSIONS

Although this study failed to identify an association between genetic variants and clinical response variability, the need to carry out related studies with larger number of cases covering other populations and genetic variants remains, which would allow the uncovering of hypothetical genetic factors governing stroke outcomes and recurrence.

Influences of genetic variants on stroke recovery: a meta-analysis of the 31,895 cases

Background

The influences of genetic variants on functional clinical outcomes following stroke are unclear. In order to reliably quantify these influences, we undertook a comprehensive meta-analysis of outcomes after acute intracerebral haemorrhage (ICH) or ischaemic stroke (AIS) in relation to different genetic variants.

Methods

PubMed, PsycInfo, Embase and Medline electronic databases were searched up to January 2019. Outcomes, defined as favourable or poor, were assessed by validated scales (Barthel index, modified Rankin scale, Glasgow outcome scale and National Institutes of Health stroke scale).

Results

Ninety-two publications comprising 31,895 cases met our inclusion criteria. Poor outcome was observed in patients with ICH who possessed the APOE4 allele: OR =2.60 (95% CI = 1.25–5.41, p = 0.01) and in AIS patients with the GA or AA variant at the BDNF-196 locus: OR = 2.60 (95% CI = 1.25–5.41, p = 0.01) or a loss of function allele of CYP2C19: OR = 2.36 (95% CI = 1.56–3.55, p < 0.0001). Poor outcome was not associated with APOE4: OR = 1.02 (95% CI = 0.81–1.27, p = 0.90) or IL6-174 G/C: OR = 2.21 (95% CI = 0.55–8.86, p = 0.26) in patients with AIS.

Conclusions

We demonstrate that recovery of AIS was unfavourably associated with variants of BDNF and CYP2C19 genes whilst recovery of ICH was unfavourably associated with APOE4 gene.

Electronic supplementary material

The online version of this article (10.1007/s10072-019-04024-w) contains supplementary material, which is available to authorized users.