NINJ2 polymorphism is associated with ischemic stroke in Chinese Han population

NINJ2 deficiency inhibits preadipocyte differentiation and promotes insulin resistance through regulating insulin signaling

OBJECTIVE

Genetic variants in ninjurin-2 (NINJ2; nerve injury-induced protein 2) confer risk of ischemic strokes and coronary artery disease as well as endothelial activation and inflammation. However, little is known about NINJ2's in vivo functions and underlying mechanisms.

METHODS

The phenotypes of NINJ2 knockout mice were analyzed, and mechanisms of NINJ2 that regulate body weight, insulin resistance, and glucose homeostasis and lipogenesis were investigated in vivo and in vitro.

RESULTS

This study found that mice lacking NINJ2 showed impaired adipogenesis, increased insulin resistance, and abnormal glucose homeostasis, all of which are risk factors for strokes and coronary artery disease. Mechanistically, NINJ2 directly interacts with insulin receptor/insulin-like growth factor 1 receptor (INSR/IGF1R), and NINJ2 knockdown can block insulin-induced mitotic clonal expansion during preadipocyte differentiation by inhibiting protein kinase B/extracellular signal-regulated kinase (AKT/ERK) signaling and by decreasing the expression of key adipocyte transcriptional regulators CCAAT/enhancer-binding protein β (C/EBP-β), C/EBP-α, and peroxisome proliferator-activated receptor γ (PPAR-γ). Furthermore, the interaction between NINJ2 and INSR/IGF1R is needed for maintaining insulin sensitivity in adipocytes and muscle via AKT and glucose transporter type 4. Notably, adenovirus-mediated NINJ2 overexpression can ameliorate diet-induced insulin resistance in mice.

CONCLUSIONS

In conclusion, these findings reveal NINJ2 as an important new facilitator of insulin receptors, and the authors propose a unique regulatory mechanism between insulin signaling, adipogenesis, and insulin resistance.

Genetic polymorphisms of MRPS30-DT and NINJ2 may influence lung cancer risk

Lung cancer is one of the malignant tumors, and genetic background is a risk factor in lung cancer that cannot be neglected. In this study, we aimed to find out the effect of MRPS30-DT and NINJ2 variants on lung cancer risk. In this study, the seven selected single-nucleotide polymorphisms (SNPs) of MRPS30-DT and NINJ2 were genotyped in 509 lung cancer patients and 501 healthy controls based on the Agena MassARRAY platform. Odds ratios and 95% confidence intervals were calculated by logistic regression analysis to evaluate association between gene polymorphisms and lung cancer risk. False-positive report probability was also used to assess false-positive results. Furthermore, the interaction between SNPs was analyzed by multifactor dimensionality reduction to predict lung cancer risk. We identified the genotype TA of rs16901963 (T < A) in MRPS30-DT as a protective factor against lung cancer, while rs16901963-TT was significantly associated with an increased risk of lung cancer. We also revealed that the effect of MRPS30-DT and NINJ2 variants on the risk of lung cancer was dependent on age, gender, smoking, and drinking status. In conclusion, this study first proved that MRPS30-DT and NINJ2 variants played important roles in affecting the susceptibility to lung cancer.

Involvement of NINJ2 Protein in Inflammation and Blood-Brain Barrier Transmigration of Monocytes in Multiple Sclerosis

Multiple sclerosis (MS) is an inflammatory neurodegenerative disorder of the central nervous system (CNS). The migration of immune cells into the CNS is essential for its development, and plasma membrane molecules play an important role in triggering and maintaining the inflammation. We previously identified ninjurin2, a plasma membrane protein encoded by NINJ2 gene, as involved in the occurrence of relapse under Interferon-β treatment in MS patients. The aim of the present study was to investigate the involvement of NINJ2 in inflammatory conditions and in the migration of monocytes through the blood-brain barrier (BBB). We observed that NINJ2 is downregulated in monocytes and in THP-1 cells after stimulation with the pro-inflammatory cytokine LPS, while in hCMEC/D3 cells, which represent a surrogate of the BBB, LPS stimulation increases its expression. We set up a transmigration assay using an hCMEC/D3 transwell-based model, finding a higher transmigration rate of monocytes from MS subjects compared to healthy controls (HCs) in the case of an activated hCMEC/D3 monolayer. Moreover, a positive correlation between NINJ2 expression in monocytes and monocyte migration rate was observed. Overall, our results suggest that ninjurin2 could be involved in the transmigration of immune cells into the CNS in pro-inflammatory conditions. Further experiments are needed to elucidate the exact molecular mechanisms.

Functional rare variant in a C/EBP beta binding site in NINJ2 gene increases the risk of coronary artery disease

Objective: NINJ2 regulates activation of vascular endothelial cells, and genome-wide association studies showed that variants in NINJ2 confer risk to stroke. However, whether variants in NINJ2 are associated with coronary artery disease (CAD) is unknown.

Methods: We genotyped rs34166160 in NINJ2 in two independent Chinese GeneID populations which included 2,794 CAD cases and 4,131 controls, and performed genetics association studies. Functional studies were also performed to reveal the mechanisms.

Results: Allele rs34166160 significantly confers risk to CAD in the GeneID Hubei population which contained 1,440 CAD cases and 2,660 CAD-free controls (observed P_-obs = 6.39 × 10⁻³ with an odds ratio (OR) was 3.39, adjusted P_-adj = 8.12 × 10⁻³ with an OR of 3.10). The association was replicated in another population, GeneID Shandong population contained 1,354 CAD cases and 1,471 controls (P_-obs = 3.33 × 10⁻³ with an OR of 3.14, P_-adj = 0.01 with an OR of 2.74). After combining the two populations, the association was more significant (P_-obs = 1.57 × 10⁻⁵ with an OR of 3.58, P_-adj = 3.41 × 10⁻⁴ with an OR of 2.80). In addition, we found that rs34166160 was associated with the mRNA expression level of NINJ2 and the flanking region of rs34166160 can directly bind with transcriptional factor CCAAT-box/enhancer-binding protein beta, and the risk A allele has more transcription activity than non-risk C allele with or without LPS in HUVEC cells.

Conclusions: Our study demonstrates that the functional rare variant rs34166160 in NINJ2 confers risk to CAD for the first time, and these findings further expand the range of the pathology of CAD and atherosclerosis.

Assessment of Association between NINJ2 Polymorphisms and Suicide Attempts in an Iranian Population

Suicidal behavior as a psychological problem with high public health burden is associated with a number of genetically determined risk factors. In the current study, we investigated the association between two polymorphisms within the NINJ2 gene and risk of suicide in an Iranian population. The study included 295 individuals who attempted suicide with soft suicide methods, 234 suicide victims and 410 normal controls. The rs11833579 SNP was associated with death from suicide in a codominant model in that the AG genotype decreased the risk of death from suicide compared with the GG genotype (OR (95% CI) = 0.49 (0.34-0.71), adjusted P value = 4e-04). This SNP was also associated with death from suicide in dominant (AG + AA versus GG: OR (95% CI) = 0.63 (0.46-0.87), adjusted P value = 0.011) and overdominant (AG versus GG + AA: OR (95% CI) = 0.49 (0.35-0.69), adjusted P value < 0.0001) models. In addition, this SNP was associated with soft suicide attempts in a codominant model (AG versus AA + GG: OR (95% CI) = 0.7 (0.5-0.98), adjusted P value = 0.02). The rs3806263 SNP was associated with death from suicide in allelic (A versus G: OR (95% CI) = 1.48 (1.17-1.88), adjusted P value = 0.002), codominant (AA versus GG: OR (95% CI) = 3.14 (1.89-5.21), adjusted P value < 0.0001), recessive (AA versus GG + AG: OR (95% CI) = 3.47 (2.15-5.61), adjusted P value < 0.0001), overdominant (AG versus AA + GG: OR (95% CI) = 0.62 (0.45-0.87), adjusted P value = 0.0092) and log-additive models (OR (95% CI) = 1.45 (1.15-1.83), adjusted P value = 0.0034). When comparing allele/genotype frequencies of this SNP between suicide victims and soft suicide attempters, significant associations were found in allelic, codominant, recessive and log-additive models. The AG haplotype (rs11833579 and rs3806263, respectively) was significantly less prevalent among suicide victims compared with controls (OR (95% CI) = 0.37 (0.26-0.52), adjusted P value < 0.0001). This haplotype was also less prevalent among suicide victims vs. soft suicide attempters (OR (95% CI) = 0.43 (0.31-0.61), adjusted P value < 0.0001). The GA haplotype (rs11833579 and rs3806263, respectively) was less frequent among suicide victims compared with controls (OR (95% CI) = 0.63 (0.45-0.89), adjusted P value = 0.0156). Finally, the AA haplotype was more prevalent among suicide victims compared with both controls (OR (95% CI) = 2.37 (1.56-3.6), adjusted P value = 0.0002) and soft suicide attempters (OR (95% CI) = 1.92 (1.32-2.78), adjusted P value = 0.0012). Thus, these two SNPs might be regarded as genetic determinants of suicide risk in Iranian populations. Further studies in different populations are needed to verify these results.

A pharmacogenetic study implicates NINJ2 in the response to Interferon-β in multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is a disease in which biomarker identification is fundamental to predict response to treatments and to deliver the optimal drug to patients. We previously found an association between rs7298096, a polymorphism upstream to the NINJ2 gene, and the 4-year response to interferon-β (IFNβ) treatment in MS patients.

OBJECTIVES

To analyse the association between rs7298096 and time to first relapse (TTFR) during IFNβ therapy in MS patients and to better investigate its functional role.

METHODS

Survival analysis was applied in three MS cohorts from different countries (n = 1004). We also studied the role of the polymorphism on gene expression using GTEx portal and a luciferase assay. We interrogated GEO datasets to explore the relationship between NINJ2 expression, IFNβ and TTFR.

RESULTS

Rs7298096_AA patients show a shorter TTFR than rs7298096_G-carriers (P_{meta-analysis} = 3 × 10^-4, hazard ratio = 1.41). Moreover, rs7298096_AA is associated with a higher NINJ2 expression in blood (p = 7.0 × 10^-6), which was confirmed in vitro (p = 0.009). Finally, NINJ2 expression is downregulated by IFNβ treatment and related to TTFR.

CONCLUSIONS

Rs7298096 could influence MS disease activity during IFNβ treatment by modulating NINJ2 expression in blood. The gene encodes for an adhesion molecule involved in inflammation and endothelial cells activation, supporting its role in MS.

Four-octyl itaconate activates Keap1-Nrf2 signaling to protect neuronal cells from hydrogen peroxide

Background

Four-octyl itaconate (OI), the itaconate’s cell-permeable derivative, can activate Nrf2 signaling via alkylation of Keap1 at its cysteine residues. The current study tested the potential neuroprotective function of OI in hydrogen peroxide (H₂O₂)-treated neuronal cells.

Methods

SH-SY5Y neuronal cells and epigenetically de-repressed (by TSA treatment) primary murine neurons were treated with OI and/or H₂O₂. Nrf2 pathway genes were examined by Western blotting assay and real-time quantitative PCR analysis. Neuronal cell death was tested by the LDH and trypan blue staining assays. Apoptosis was tested by TUNEL and Annexin V assays.

Results

In SH-SY5Y neuronal cells and primary murine neurons, OI activated Nrf2 signaling, causing Keap1-Nrf2 disassociation, Nrf2 protein stabilization and nuclear translocation, as well as expression of Nrf2-regulated genes (HO1, NQO1 and GCLC) and ninjurin2 (Ninj2). Functional studies showed that OI attenuated H₂O₂-induced reactive oxygen species (ROS) production, lipid peroxidation and DNA damage as well as neuronal cell death and apoptosis. shRNA-mediated knockdown, or CRISPR/Cas9-induced knockout of Nrf2 almost abolished OI-induced neuroprotection against H₂O₂. Keap1 is the primary target of OI. Keap1 knockout by CRISPR/Cas9 method mimicked and abolished OI-induced actions in SH-SY5Y cells. Introduction of a Cys151S mutant Keap1 in SH-SY5Y cells reversed OI-induced Nrf2 activation and anti-H₂O₂ neuroprotection.

Conclusions

OI activates Keap1-Nrf2 signaling to protect SH-SY5Y cells and epigenetically de-repressed primary neurons from H₂O₂ in vitro.

Electronic supplementary material

The online version of this article (10.1186/s12964-018-0294-2) contains supplementary material, which is available to authorized users.

Association Between KCNQ1 Genetic Variants and Type 2 Diabetes in the Uyghur Population

OBJECTIVE

To investigate the association between KCNQ1 gene polymorphisms and type 2 diabetes (T2D) in an admixed ethnic minority, Uyghur population, living in the Northwest region of China.

MATERIALS AND METHODS

We genotyped three tagging single-nucleotide polymorphisms rs2283171, rs11023485, and rs2283208 of the KCNQ1 gene in 1006 T2D participants and 1004 controls and conducted association analysis.

RESULTS

The frequencies of the AG and GG genotypes and the G allele of rs2283171 were higher in the control group (51.4%, 22%, and 47.7%, respectively) than in the case group (49%, 17.6%, and 42.1%, respectively). The minor G allele decreased the risk of T2D with a per-allele odds ratio of 0.79 (95% CI: 0.70-0.90) for the additive genetic model in univariate analysis (p = 0.0001). After adjustment for the covariates of age, gender, smoking, alcohol use, systolic blood pressure (SBP), diastolic blood pressure (DBP), body mass index (BMI), triglyceride (TG), and total cholesterol (TC), the diabetic protective effect of the rs2283171-G allele remained. No difference was observed in the frequency distributions of the rs11023485 and rs2283208 genotypes between the two groups.

CONCLUSION

We identified a novel association between rs2283171 of KCNQ1 and T2D in the Uyghur population. Further association and functional studies are required to identify the causal functional variant that is in linkage disequilibrium with this polymorphism.

Genes underlying positive influence of prenatal environmental enrichment and negative influence of prenatal earthquake simulation and corrective influence of Chinese herbal medicine on rat offspring: Irf7 and Ninj2

BACKGROUND

Prenatal environmental enrichment (EE) has been proven to positively affect but prenatal stress negatively influence the physiological and psychological processes in animals, whose trans-generational genetic mechanism remains unclearly defined. We aimed to investigate and find out key genes underlying the positive-negative effects derived from prenatal interventions.

MATERIALS AND METHODS

Pregnant rats were randomized into EE group (EEG), earthquake simulation group (ESG), herbal group (HG) received herbal supplements in feed after earthquake simulation, and control group (CG).

RESULTS

Light Box Defecation Test (LBDT) showed EEG offspring presented less fecal pellets than CG offspring, ESG's more than CG's, and HG's less than ESG (p's<0.05). Open-field Test (OFT) score of EEG was higher than CG offspring, of ESG's was lower than CG's, and HG's higher than ESG's. Irf7 and Ninj were screened, which were up-regulated in EEG, down-regulated in ESG (FC<0.5), and were neutralized in HG. Prenatal EE could positively promote the nervous system development, prenatal earthquake simulation could retard the nervous system development and Chinese herbal remedy (JKSQW) which could correct the retardation.

CONCLUSION

The negative-positive prenatal effect could contribute to altered gene expression of Irf7 and Ninj2 which also could play a key role in the improving function of JKSQW for the kidneys.

Clinical neurogenetics: stroke

Understanding the genetic architecture of cerebrovascular disease holds promise of novel stroke prevention strategies and therapeutics that are both safe and effective. Apart from a few single-gene disorders associated with cerebral ischemia or intracerebral hemorrhage, stroke is a complex genetic phenotype that requires careful ascertainment and robust association testing for discovery and validation analyses. The recently uncovered shared genetic contribution between clinically manifest stroke syndromes and closely related intermediate cerebrovascular phenotypes offers effective and efficient approaches to complex trait analysis.

Is there a role for endogenous retroviruses to mediate long-term adaptive phenotypic response upon environmental inputs?

Endogenous retroviruses (ERVs) are long terminal repeat-containing virus-like elements that have colonized approximately 10 per cent of the present day mammalian genomes. The intracisternal A particles (IAPs) are a class of ERVs that is currently highly active in the rodents. IAP elements can influence the transcription profile of nearby genes by providing functional promoter elements and modulating local epigenetic landscape through changes in DNA methylation and histone (H3K9) modifications. Despite the potential role for IAPs in gene regulation, the precise genomic locations where these elements are integrated are not well understood. To address this issue, we have identified more than 400 novel IAP insertion sites within/near annotated genes by searching the murine genome, which suggests that the impact of IAP elements on local and/or global gene regulation could be more profound than was previously expected. On the basis of our independent analyses and already published reports, here we argue that IAPs and ERV elements in general could have an evolutionary role for modulating phenotypic plasticity upon environmental inputs, and that this could be mediated through specific stages of embryonic development such as placentation during which the epigenetic constraints on IAP elements are partially relaxed.

Lack of association between two key SNPs on chromosome 12p13 and ischemic stroke in Chinese Uyghur population

Recent genome-wide association studies (GWAS) have identified two key SNPs (rs11833579 and rs12425791) on chromosome 12p13 that were significantly associated with stroke in Caucasians. However, the validity of the association has remained controversial. We performed genetic association analyses in a very unique population which has 60% European ancestry and 40% East Asian ancestry. No significant association between these two SNPs and ischemic stroke was detected in this Chinese Uyghur population.

Association between 12p13 SNPs rs11833579/rs12425791 near NINJ2 gene and ischemic stroke in East Asian population: evidence from a meta-analysis

BACKGROUND

Meta-analysis in European population found no association between rs12425791/rs11833579 and ischemic stroke. Several studies focused on East Asians have evaluated the association between this two SNPs and risk of ischemic stroke, but the results have been inconsistent. The aim of this study was to perform a meta-analysis to investigate a more authentic association between rs12425791 and rs11833579 G>A mutation and ischemic stroke in East Asian population, as well as in Chinese Han population.

METHODS

Systematic searches of electronic databases Embase, PubMed, Web of Science, and CBM as well as hand searching of the references of identified articles and the meeting abstracts were performed. Study selection, data abstraction and study quality evaluation were independently conducted in duplicate. Statistical analyses were performed using software Stata 11.0. The pooled odds ratios (ORs) with 95% confidence intervals (95%CIs) were performed. Different effects models were used according to the difference in heterogeneity. Publication bias was tested by Begg's funnel plot and Egger's regression test.

RESULTS

A total of 4 publications including 7 studies were involved. For rs12425791, significant association was found in allelic model (OR=1.06, 95%CI=1.00-1.11) and dominant model (OR=1.10, 95%CI=1.03-1.18), whereas no evidence of association was found for additive model (OR=1.04, 95%CI=0.93-1.17) and for recessive model (OR=0.99, 95%CI=0.88-1.10). For rs11833579, no evidence of association was found for all genetic models. In the analysis of Chinese Han population, there is lack of evidence for association of ischemic stroke for both SNPs.

CONCLUSIONS

In summary, our meta-analysis suggests that rs12425791 is significantly associated with ischemic stroke in East Asian population but not Chinese Han population, of which A alleles increase the risk of ischemic stroke, whereas no evidence of association was found for rs11833579 in East Asian population as well as Chinese Han population.