Two functional promoter polymorphisms of neuregulin 1 gene are associated with progressive forms of multiple sclerosis

Significant Association of rs77493513 Polymorphism in 3'-UTR of the NRG1 Gene with the Risk of Multiple Sclerosis Disease

Multiple sclerosis (MS) is a chronic inflammatory and autoimmune disease characterized by demyelination of the central nervous system (CNS). Neuregulin 1 (NRG1) is a signaling protein that plays an important role in a variety of biological processes, including potentiate oligodendrocyte differentiation and myelination in the CNS, immune response regulation, and inflammation. Single nucleotide polymorphism (SNP) rs77493513 is located in the untranslated region of the 3' mRNA (3'-UTR) of the NRG1 gene, which is predicted to be the binding site of several microRNAs and may play an important role in post-transcriptional regulation. Study aimed to investigate the association of SNP rs77493513 in the NRG1 gene with the risk of MS disease. In this study, genomic DNA was extracted from whole blood samples of 182 patients with relapsing-remitting multiple sclerosis (RRMS) and 198 controls. Different genotypes of rs77493513 polymorphism were determined using RFLP-PCR technique. Statistical analysis was performed using SPSS 21.0 software and by t, χ2 and logistic regression tests. Our data showed that genotypes AC (OR=3.63, CI= 1.93-6.81, p<0.001) and CC (OR=7.90, CI= 4.13-15.11, p<0.001) significantly increased the risk of MS disease and C allele is risk allele. Also, AC (OR=0.16, CI= 0.04-0.63, p= 0.009) and CC (OR=0.14, CI= 0.03-0.53, p=0.04) genotypes significantly decrease the age of onset of the disease. The results show that allele C of rs77493513 polymorphism in the NRG1 gene can be a risk factor for MS.

Neuregulin-1 beta 1 is implicated in pathogenesis of multiple sclerosis

Multiple sclerosis is characterized by immune mediated neurodegeneration that results in progressive, life-long neurological and cognitive impairments. Yet, the endogenous mechanisms underlying multiple sclerosis pathophysiology are not fully understood. Here, we provide compelling evidence that associates dysregulation of neuregulin-1 beta 1 (Nrg-1β1) with multiple sclerosis pathogenesis and progression. In the experimental autoimmune encephalomyelitis model of multiple sclerosis, we demonstrate that Nrg-1β1 levels are abated within spinal cord lesions and peripherally in the plasma and spleen during presymptomatic, onset and progressive course of the disease. We demonstrate that plasma levels of Nrg-1β1 are also significantly reduced in individuals with early multiple sclerosis and is positively associated with progression to relapsing-remitting multiple sclerosis. The functional impact of Nrg-1β1 downregulation preceded disease onset and progression, and its systemic restoration was sufficient to delay experimental autoimmune encephalomyelitis symptoms and alleviate disease burden. Intriguingly, Nrg-1β1 therapy exhibited a desirable and extended therapeutic time window of efficacy when administered prophylactically, symptomatically, acutely or chronically. Using in vivo and in vitro assessments, we identified that Nrg-1β1 treatment mediates its beneficial effects in EAE by providing a more balanced immune response. Mechanistically, Nrg-1β1 moderated monocyte infiltration at the blood-CNS interface by attenuating chondroitin sulphate proteoglycans and MMP9. Moreover, Nrg-1β1 fostered a regulatory and reparative phenotype in macrophages, T helper type 1 (Th1) cells and microglia in the spinal cord lesions of EAE mice. Taken together, our new findings in multiple sclerosis and experimental autoimmune encephalomyelitis have uncovered a novel regulatory role for Nrg-1β1 early in the disease course and suggest its potential as a specific therapeutic target to ameliorate disease progression and severity.

Whole transcriptome analysis of multiple Sclerosis patients reveals active inflammatory profile in relapsing patients and downregulation of neurological repair pathways in secondary progressive cases

BACKGROUND

Multiple sclerosis (MS) is an inflammatory autoimmune neurologic disease that causes progressive destruction of myelin sheath and axons. Affecting more than 2 million people worldwide, MS may presents distinct clinical courses. However, information regarding key gene expression and genic pathways related to each clinical form is still limited.

OBJECTIVE

To assess the whole transcriptome of blood leukocytes from patients with remittent-recurrent (RRMS) and secondary-progressive (SPMS) forms to explore the gene expression profile of each form.

METHODS

Total RNA was obtained and sequenced in Illumina HiSeq platform. Reads were aligned to human genome (GRCh38/hg38), BAM files were mapped and differential expression was obtained with DeSeq2. Up or downregulated pathways were obtained through Ingenuity IPA. Pro-inflammatory cytokines levels were also assessed.

RESULTS

The transcriptome was generated for nine patients (6 SPMS and 3 RRMS) and 5 healthy controls. A total of 731 and 435 differentially expressed genes were identified in SPMS and RRMS, respectively. RERE, IRS2, SIPA1L1, TANC2 and PLAGL1 were upregulated in both forms, whereas PAD2 and PAD4 were upregulated in RRMS and downregulated in SPMS. Inflammatory and neuronal repair pathways were upregulated in RRMS, which was also observed in cytokine analysis. Conversely, SPMS patients presented IL-8, IL-1, Neurothrophin and Neuregulin pathways down regulated.

CONCLUSIONS

Overall, the transcriptome of RRMS and SPMS clearly indicated distinct inflammatory profiles, where RRMS presented marked pro-inflammatory profile but SPMS did not. SPMS individuals also presented a decrease on expression of neuronal repair pathways.

The expression of lnc-IL-7R long non-coding RNA dramatically correlated with soluble and membrane-bound isoforms of IL-7Ra gene in multiple sclerosis patients

BACKGROUND AND PURPOSE

Multiple sclerosis (MS) is a neurological disease of the central nervous system (CNS) that causes physical and cognitive impairments. IL-7Ra is a key non-MHC gene associated with MS. IL-7Ra is a likely functional candidate for this complex disease because it is involved in the development, maturation, and homeostasis of T and B cells. Our aim was to evaluate the expression level and controlling role of lnc-IL-7R in the expression of two variants of IL-7Ra in MS patients versus healthy controls and their correlation with certain clinical features.

METHODS

Using the real-time PCR method, we analyzed the expression levels of membrane-bound (IL-7RB) and soluble (IL-7RS) isoforms of IL-7R gene and lnc-IL-7R in 36 MS patients versus 30 healthy controls.

RESULTS

Our results revealed no significant difference between the expression levels of IL-7RB and IL-7RS isoforms of IL-7R gene and lnc-IL-7R in MS patients versus healthy controls (p=0.7, p=0.6 and p=0.8, respectively). Moreover, we found a significant correlation between the expression levels of IL-7RB with lnc-IL-7R, IL-7RS with lnc-IL-7R and IL-7RB with IL-7RS in both patient and control groups.

CONCLUSIONS

We have probably uncovered new evidence for the controlling role of long non-coding RNAs in the expression level of genes and their roles in MS.

Association study of two functional single nucleotide polymorphisms of neuropeptide y gene with multiple sclerosis

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system characterized by brain inflammation, demyelination and axonal loss. Neuropeptide Y (NPY) has a critical role in the maintenance of homeostasis in the immune system and coping of stress condition. In the current study we analyzed 188 patients suffering from MS and 204 unrelated healthy controls for two functional single nucleotide polymorphisms (SNPs), NPY 20T>C (rs16139) and NPY -485T>C (rs16147) using PCR-RFLP and Mismatch PCR-RFLP methods. Our results demonstrated that homozygocity in the minor allele for NPY -485T>C polymorphism is associated with the MS risk in patients in compare with healthy controls (CC vs. TT, P=0.033; CC vs. TT+TC, P=0.02). In addition, by comparison with allele T, the frequency of NPY -485C allele was higher in cases than in control subjects and present increased risk of MS, but statistically significant was borderline (P=0.053). The stratification for disease progression revealed a significant difference in the allelic and genotypic distribution between subgroups of MS and controls. The frequency of the CC genotype and C allele was higher in the primary progressive MS patients when compared with control group (CC vs. TT, P=0.019; CC vs. TT+TC, P=0.008; C vs. T, P=0.022). In addition, the frequency of CC genotype was higher in the relapsing remitting MS patients when compared with control group (CC vs. TT, P=0.034; CC vs. TT+TC, P=0.016). Haplotype analysis demonstrated that the haplotype 3 (CT) is more common in RR MS (P=0.041), and PP MS (P=0.031) than control group. In conclusion, the obtained results demonstrate the probable role of NPY SNPs in susceptibility to MS within the Iranian population.