Single-nucleotide polymorphism rs948854 in human galanin gene and multiple sclerosis: a gender-specific risk factor

Association between MEF2 family gene polymorphisms and susceptibility to multiple sclerosis in Chinese population

PURPOSE

Multiple sclerosis (MS) is an autoimmune disease characterized by inflammatory demyelinating lesions in the white matter of the central nervous system. Myocyte enhancer factor 2 (MEF2) family genes play important roles in the immune response. This study focuses on the relationship between MEF2 family gene polymorphisms and MS.

METHODS

A total of 174 MS patients and 120 healthy controls were recruited. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to analyze the gene polymorphisms of MEF2D and MEF2C. In addition, peripheral blood was collected and leukocytes were isolated. The transcription level of MEF2D in the two groups of samples was detected with quantitative real time polymerase chain reaction (qRT-PCR).

RESULTS

We found that the C allele frequency and CC genotype frequency of rs2274316 in MEF2D were significantly higher in MS patients. The C allele and CT genotype distribution for rs3790455 were significantly more frequent in MS patients. Female patients showed higher CC genotype frequency of rs2274316. The genotype frequency distribution of rs2274316 and rs3790455 were not related to onset age and phenotype of MS patients. In addition, this study also proved that MEF2D was significantly overexpressed in the peripheral blood leukocytes of MS patients. The transcription level of MEF2D was significantly higher in patients with CC genotype of rs2274316.

CONCLUSION

These findings suggest rs2274316 and rs3790455 of MEF2D gene are potential genetic risk factors for MS in Chinese population. The transcription level of MEF2D is also associated with susceptibility to MS and MEF2D gene polymorphisms.

Sex-dependent effect of APOE on Alzheimer's disease and other age-related neurodegenerative disorders

The importance of apolipoprotein E (APOE) in late-onset Alzheimer's disease (LOAD) has been firmly established, but the mechanisms through which it exerts its pathogenic effects remain elusive. In addition, the sex-dependent effects of APOE on LOAD risk and endophenotypes have yet to be explained. In this Review, we revisit the different aspects of APOE involvement in neurodegeneration and neurological diseases, with particular attention to sex differences in the contribution of APOE to LOAD susceptibility. We discuss the role of APOE in a broader range of age-related neurodegenerative diseases, and summarize the biological factors linking APOE to sex hormones, drawing on supportive findings from rodent models to identify major mechanistic themes underlying the exacerbation of LOAD-associated neurodegeneration and pathology in the female brain. Additionally, we list sex-by-genotype interactions identified across neurodegenerative diseases, proposing APOE variants as a shared etiology for sex differences in the manifestation of these diseases. Finally, we present recent advancements in 'omics' technologies, which provide a new platform for more in-depth investigations of how dysregulation of this gene affects the development and progression of neurodegenerative diseases. Collectively, the evidence summarized in this Review highlights the interplay between APOE and sex as a key factor in the etiology of LOAD and other age-related neurodegenerative diseases. We emphasize the importance of careful examination of sex as a contributing factor in studying the underpinning genetics of neurodegenerative diseases in general, but particularly for LOAD.

The combined effect of IL-17F and CCL20 gene polymorphism in susceptibility to multiple sclerosis in Egypt

BACKGROUND

Levels of CCL20 and its CCR6 receptor are elevated in many autoimmune diseases which help in the recruitment of T helper (Th17) cells to site of inflammation.

OBJECTIVES

Determine the value of single nucleotide polymorphism of CCL20 (rs6749704) and IL-17F (rs763780) genes and their concomitant effect on the serum CCL20 level and susceptibility to MS in Egyptian patients.

SUBJECTS AND METHODS

Blood samples were collected from 83 patients and 95 healthy subjects. Serum levels of CCL20 were measured by ELISA. The DNA was analyzed for rs6749704 and rs763780 using Genotyping Taqman assay.

RESULTS

The mean serum levels of CCL20 in the MS group were significantly higher than healthy group (P < 0.001). Frequencies of CT genotype of rs6749704 in CCL20 gene and C allele in MS patients were significantly higher compared to controls. Also significant increase of rs763780 in IL-17F gene was detected in MS patients. Concomitant polymorphism in both genes in MS patients showed an increase risk to MS rather than individual locus.

CONCLUSION

CCL20 may play an important role in the pathogenesis of MS. Both allelic variation of (rs6749704) within CCL20 gene and (rs763780) within IL-17F gene can be considered risk factor for development of MS in Egyptian patients.

A non-functional galanin receptor-2 in a multiple sclerosis patient

Multiple Sclerosis (MS) is an inflammatory neurodegenerative disease that affects approximately 2.5 million people globally. Even though the etiology of MS remains unknown, it is accepted that it involves a combination of genetic alterations and environmental factors. Here, after performing whole exome sequencing, we found a MS patient harboring a rare and homozygous single nucleotide variant (SNV; rs61745847) of the G-protein coupled receptor (GPCR) galanin-receptor 2 (GALR2) that alters an important amino acid in the TM6 molecular toggle switch region (W249L). Nuclear magnetic resonance imaging showed that the hypothalamus (an area rich in GALR2) of this patient exhibited an important volumetric reduction leading to an enlarged third ventricle. Ex vivo experiments with patient-derived blood cells (AKT phosphorylation), as well as studies in recombinant cell lines expressing the human GALR2 (calcium mobilization and NFAT mediated gene transcription), showed that galanin (GAL) was unable to stimulate cell signaling in cells expressing the variant GALR2 allele. Live cell confocal microscopy showed that the GALR2 mutant receptor was primarily localized to intracellular endosomes. We conclude that the W249L SNV is likely to abrogate GAL-mediated signaling through GALR2 due to the spontaneous internalization of this receptor in this patient. Although this homozygous SNV was rare in our MS cohort (1:262 cases), our findings raise the potential importance of impaired neuroregenerative pathways in the pathogenesis of MS, warrant future studies into the relevance of the GAL/GALR2 axis in MS and further suggest the activation of GALR2 as a potential therapeutic route for this disease.

Sex/gender influences on the nervous system: Basic steps toward clinical progress

A Commentary highlighting the progress that sex-based data and research have made in neuroscience and the complexities that research has revealed thus far. Basic and preclinical neuroscientific research that considers sex as a biological variable will continue to build on the foundation of knowledge that has been started by multiple predecessors. The expansion of knowledge in preclinical neuroscience that integrates the study of both sexes will have a significant role in informing clinical trial design. We applaud the efforts of the editors and authors who have contributed to this issue. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.