A genetic interaction of NRXN2 with GABRE, SYT1 and CASK in migraine patients: a case-control study

DOI: https://doi.org/10.1186/s10194- 021- 01266- y

Abstract-Summary Our aim was to continue exploring the role and interaction of proteins involved in the control and promotion of neurotransmission in migraine susceptibility.

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Tagging single nucleotide polymorphisms of NRXN2 were genotyped to assess

the association between NRXN2 and migraine susceptibility.

We found a statistically significant interaction model (p = 0.009) in the female group between the genotypes CG of rs477138 (NRXN2) and CT of rs1158605 (GABRE).

This interaction was validated by logistic regression, showing a significant risk

effect [OR = 4.78 (95%CI: 1.76–12.97)] after a Bonferroni correction.

Our data also supports a statistically significant interaction model (p = 0.011) in the female group between the GG of rs477138 in NRXN2 and, the rs2244325's GG genotype and rs2998250’s CC genotype of CASK.

This interaction was also validated by logistic regression, with a protective effect

[OR = 0.08 (95%CI: 0.01–0.75)].

A weak interaction model was found between NRXN2-SYT1. We have not found any statistically significant allelic or haplotypic associations

between NRXN2 and migraine susceptibility.

This study unravels, for the first time, the gene-gene interactions between NRXN2, GABRE - a GABAA-receptor - and CASK, importantly it shows the syn- ergetic effect between those genes and its relation with migraine susceptibility.

These gene interactions, which may be a part of a larger network, can potentially help us in better understanding migraine aetiology and in development of new thera- peutic approaches.

Background Candidate gene association studies, including in our population, have focused on pathways related to migraine triggers and pathophysiology, namely in genes involved in the vascular and hormonal component and in the release of neurotrans- mitters [70, 71].

In our population, an involvement of GABAA-R genes in migraine’s susceptibil-

ity was already described [61].

Genetic interactions in migraine susceptibility have already been described by

others as well as by our group [61, 72, 73].

We consider that the intricacy of migraine does not stem only from the action of

a single or several genes, but from an entangled genetic network between them.

We aimed to further investigate the role and interaction of NRXN2, SYT1, GABRE and CASK, additional components involved in the control mechanisms of neurotransmitter release apparatus in migraine susceptibility.

Material & Methods This case-control study was conducted in a sample of patients selected at the outpa- tient neurologic clinic at Hospital de Santo António (HIS-CHP), Porto.

For rs2269730, genotyping was performed by Sanger sequencing with Big Dye® Terminator Cycle Sequencing 1.1 Ready Reaction (Applied Biosystems) according to standard procedure.

Based on the interactions identified in STRING, we then assessed a possible statistical interaction between variants in these gene sets: NRXN2-SYT1, NRXN2- GABRE and NRXN2-CASK in migraine, using the Multifactor Dimensionality

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2 Mechanisms

Reduction (MDR) v2.0, a software for the identification of SNP combinations related to disease susceptibility using nonparametric methods and genetic model- free procedures [74].

Taking into account the meaningful and significant gene-gene interactions found by MDR we performed a, multivariable-logistic regression for those variants (con- sidering the most frequent homozygote as the reference) to statistically validate those results.

Results To better characterize the contribution of NRXN2-related genes to migraine vari- ability, we explored potential protein interactions with a confidence score higher than 0.90 and supported by experiments and functional enrichments pathways.

We found 2 strong synergistic interactions, demonstrated by both MDR software and logistic regression analyses, between migraine susceptibility and NRXN2- GABRE and NRXN2-CASK.

As these results were not consistent between the two analyses, we did not pre- sume an interaction between the SNPs evaluated in these two genes on migraine susceptibility.

Discussion We for the first time show that the genetic interaction and synergetic effect between variants in NRXN2, GABRE and CASK, affects migraine predisposition.

We also verified the evidence for genetic interaction between NRXN2 and CASK

in migraine susceptibility.

Even though a biological link has been shown between proteins such as SYT through the binding to the disordered carboxyterminal domain of neurexins [75], our results do not establish a role for their genetic interaction in migraine susceptibility.

Indication of genetic interaction in migraine predisposition has been previously shown, namely, our group had found a robust gene-gene interaction between BDNF and CGRP and between GABAA-R genes, in migraine susceptibility [61, 72].

These studies reinforce the importance of investigating interactions among can- didate genes in migraine pathophysiology and also support the genetic interplay in the susceptibility of this disorder.

We found a very significant (two-way) interaction in females between NRXN2-

GABRE and NRXN2-CASK associated with migraine susceptibility.

Conclusions No studies have aimed at associating the neurexin genes with migraine.

Acknowledgement A machine generated summary based on the work of Alves-Ferreira, Miguel; Quintas, Marlene; Sequeiros, Jorge; Sousa, Alda; Pereira-Monteiro, José; Alonso, Isabel; Neto, João Luís; Lemos, Carolina. 2021  in The Journal of Headache and Pain.

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Changes in the gene expression profile during spontaneous migraine attacks