Complete sequence analysis of human toll-like receptor 3 gene in natural killer cells of multiple sclerosis patients

Abstract

Background: Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system (CNS) where both environmental and genetic risk factors play a role. Among the environmental risk factors, EBV and HSV infections have been suggested as strong candidates contributing to MS pathology/progression. Viral recognition and control is largely tasked to the NK cells via TLR recognition and various cytotoxic and immunoregulatory functions. The present work aimed to characterize NK cells isolated from MS patients for genetic polymorphisms in the gene encoding for TLR3, as TLR3 in NK cells is important in herpesvirus recognition. Methods: Highly purified NK cells isolated from peripheral blood of MS patients (n = 27) and healthy controls (n = 30) were used to sequence all five exons of the TLR3 gene using sanger sequencing. Alignment of the obtained sequences with the wild-type TLR3 sequence was used to identify genetic polymorphisms within the TLR3 gene. Results: The alignment identified multiple substitution mutations across the five exons of the TLR3 gene (rs116729895, rs3775296, rs377529, rs3775290, rs3775291, rs376735334 and rs73873710). A significant difference was observed in the allele distribution of rs3775291 (Leu412Phe) between MS patients and HC, whereby the minor allele was detected in 38.9% of MS patients versus 11% of HC (Fisher's exact test, p = 0.021). Conclusion: There appears to be a possible association between the TLR3 missense mutation rs3775291 and multiple sclerosis, which might be attributed to changes in the TLR3 functional properties.

The expression profile of virus-recognizing toll-like receptors in natural killer cells of Cypriot multiple sclerosis patients

“…However, we have recently found such an association, i.e. between a TLR3 variant (rs3775291) and MS, in the Cypriot MS population [24]. This discrepancy can be explained by the imbalance in genetic studies that favour North American and North European studies, as opposed to a more diversified approach.…”

“…Blood samples were collected from MS patients during their routine follow-up visits at the neurology clinic C of The Cyprus Institute of Neurology and Genetics. As described previously [24], the inclusion criteria were: (1) individuals above 18 years of age;…”

“…Blood samples were collected from MS patients during their routine follow-up visits at the neurology clinic C of The Cyprus Institute of Neurology and Genetics. As described previously [ 24 ], the inclusion criteria were: (1) individuals above 18 years of age; (2) MS patients with clinically definite multiple sclerosis (CDMS) and clear relapsing–remitting clinical course; (3) patients not experiencing any relapse symptoms at the time of blood collection; (4) availability of a detailed clinical history (age of onset, disease duration, Expanded Disability Status Scale (EDSS) score, and treatments received); (5) being born and having resided in Cyprus from birth to early adult life at the least. Exclusion criteria were: (1) patients having suffered a relapse episode within 30 days before enrolment and/or blood collection; (2) inability or unwillingness to provide informed consent; (3) a history of alcohol or drug abuse; (4) pregnancy.…”

Association of TLR3 gene 1377C/T (rs3775290) and TLR7 gene C/G (rs3853839) polymorphism with hand, foot, and mouth disease caused by human enterovirus 71 infection susceptibility and severity in the Chinese Han population: A meta-analysis of case-control studies

“…This study systematically evaluated the susceptibility of individuals with polymorphisms in TLR3 and TLR7 genes to HFMD and susceptibility to the severe type. Polymorphism of rs3775290 is in exon 4 of the TLR3 gene, which is a synonymous mutation that does not lead to amino acid change, [ 27 ] while polymorphism of rs3853839 is in the 3’ untranslated region (UTR) of the TLR7 gene and leads to changes in hsa-miR-298, which is a typical miRNA binding change of 3’ UTR. [ 28 ] The results suggested that the susceptibility to the severe type increased considering the comparison of T allele relative to C allele in TLR3 rs3775290 polymorphism, and the difference was statistically significant.…”

Role of Toll-Like Receptors in Neuroimmune Diseases: Therapeutic Targets and Problems

“…TLR3, TLR7, TLR8 and TLR9 also play an irreplaceable role in the pathogenesis of MS. Elie et al detected TLR3 polymorphism in NK cells from MS patients, and they found that the rs3775291 allele was significantly different between MS and healthy controls (HC), and the rs3775291 (C/T or T/T) increased the incidence of MS by 71% compared with the homozygous genotype (C/C). They proposed that TLR3 mutations in NK cells are associated with MS susceptibility (67), whether the same conditions can be observed in humans in other regions or countries remains to be studied. Polyinosinicpolycytidylic acid [Poly(I:C)], a TLR3 agonist, can suppress demyelination in EAE by inducing endogenous IFN-b and peripheral CC chemokine CCL2 production (68).…”