Polymorphism of PARP-1 indicates an increased risk and a worse initial severity of ischemic stroke

Functional genetic variation in 3'UTR of PARP1 indicates a decreased risk and a better severity of ischemic stroke

Aim of the study: Polymorphisms of DNA repair enzyme gene may alter the ability of damage repair, ischemic stroke susceptibility and outcome. This study aimed to explore the association of polymorphisms in PARP1 and the effects of interactions between genes in Chinese.Materials and methods: A total of 500 patients and 500 healthy controls were enrolled for genotyping. Results: Clinical information analysis revealed higher levels of alcohol and smoking exposure in patients with ischemic stroke, as well as chronic conditions such as diabetes, hypertension, and higher serum triglycerides concentration. In addition, Polymorphism in PARP1 rs8679 was significantly associated with the decreased ischemic stroke risk. Patients harboring the PARP1 rs8679 AG/GG genotype had a better initial stroke, and as for the mRNA level of PARP1, it was suppressed with mutant genotype in comparison with the wild genotype. Finally, the suppressed of PARP1 was induced by gain-binding ability of miR-124-5p through 3'UTR directly binding.Conclusions: In conclusion, our study demonstrates that the SNP rs8679 in PARP1 3'-UTR might act as a protective factor for the outcome of patients with ischemic stroke.

Poly (ADP-Ribose) Polymerase 1 Regulates Cajal-Retzius Cell Development and Neural Precursor Cell Adhesion

Poly (ADP-ribose) polymerase 1 (PARP1) is a ubiquitously expressed enzyme that regulates DNA damage repair, cell death, inflammation, and transcription. PARP1 functions by adding ADP-ribose polymers (PAR) to proteins including itself, using NAD⁺ as a donor. This post-translational modification known as PARylation results in changes in the activity of PARP1 and its substrate proteins and has been linked to the pathogenesis of various neurological diseases. PARP1 KO mice display schizophrenia-like behaviors, have impaired memory formation, and have defects in neuronal proliferation and survival, while mutations in genes that affect PARylation have been associated with intellectual disability, psychosis, neurodegeneration, and stroke in humans. Yet, the roles of PARP1 in brain development have not been extensively studied. We now find that loss of PARP1 leads to defects in brain development and increased neuronal density at birth. We further demonstrate that PARP1 loss increases the expression levels of genes associated with neuronal migration and adhesion in the E15.5 cerebral cortex, including Reln. This correlates with an increased number of Cajal–Retzius (CR) cells in vivo and in cultures of embryonic neural progenitor cells (NPCs) derived from the PARP1 KO cortex. Furthermore, PARP1 loss leads to increased NPC adhesion to N-cadherin, like that induced by experimental exposure to Reelin. Taken together, these results uncover a novel role for PARP1 in brain development, i.e., regulation of CR cells, neuronal density, and cell adhesion.

Emerging role of PARP-1 and PARthanatos in ischemic stroke

Cell death is a key feature of neurological diseases, including stroke and neurodegenerative disorders. Studies in a variety of ischemic/hypoxic mouse models demonstrate that poly(ADP-ribose) polymerase 1 (PARP-1)-dependent cell death, also named PARthanatos, plays a pivotal role in ischemic neuronal cell death and disease progress. PARthanatos has its unique triggers, processors, and executors that convey a highly orchestrated and programmed signaling cascade. In addition to its role in gene transcription, DNA damage repair, and energy homeostasis through PARylation of its various targets, PARP-1 activation in neuron and glia attributes to brain damage following ischemia/reperfusion. Pharmacological inhibition or genetic deletion of PARP-1 reduces infarct volume, eliminates inflammation, and improves recovery of neurological functions in stroke. Here, we reviewed the role of PARP-1 and PARthanatos in stroke and their therapeutic potential.

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.