Toll-Like Receptor (TLR)-9 rs352140 Polymorphism is an Immunopathology Protective Factor in Parkinson's Disease in the Northern Iranian Population

Background: Neuroinflammation and immunopathology in Parkinson's disease (PD) is believed to be associated with genetic and environmental factors. Objective: We conducted the current study to evaluate the Toll-like receptors (TLR4 and TLR9) genes polymorphism in the patients suffering from Parkinson's disease in northern Iran. Methods: In this study, we extracted DNA from peripheral blood samples of unrelated 100 cases of Parkinson's disease and 100 healthy-matched controls with the mean age of 69.98 and 71.94 years, respectively. Subsequently, single-nucleotide polymorphisms (SNPs) of TLR4 and TLR9 were genotyped through restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR). The outcomes were confirmed employing Sanger sequencing. For the analysis of our data, we utilized SNPStats software and SPSS 22. Results: Our findings indicated that the allele distribution was meaningfully different in the PD group compared with the healthy control (p=0.02) with respect to rs352140 belonging to TLR9 gene. Moreover, rs352140T allele carriers were observed to be correlated with PD reduced risk (TT + TC vs. CC). The dominant rs352140 model was approved as the most acceptable inheritance model for fitting the data (OR 0.41, 95% CI 0.23-0.75, p=0.0031). Additionally, haplotype analysis revealed a meaningful correlation between TLR9 polymorphisms and Parkinson's disease. Conclusion: The obtained results in this study indicated that rs352140T of TLR9 gene was a protective factor in Parkinson's disease. Furthermore, this SNP could be an efficient prognosis and may be a prophylactic or therapeutic target. However, future investigations are of great necessity.