The rs12826786 in HOTAIR lncRNA Is Associated with Risk of Autism Spectrum Disorder

Key Non-coding Variants in Three Neuroapoptosis and Neuroinflammation-Related LncRNAs Are Protectively Associated with Susceptibility to Parkinson's Disease and Some of Its Clinical Features

Research findings show that genetic susceptibility to sporadic Parkinson's disease (PD), a common neurodegenerative disorder, is determined through gene variation of loci involved in its development and pathogenesis. A growing body of strong evidence has revealed that dysfunction of long non-coding RNAs (lncRNAs) plays key roles in the pathogenesis and progression of PD through impairing neuronal signaling pathways, but little is known about the relationship between their variants and PD susceptibility. In this research, we intended to study the relationship between functional SNPs rs12826786C>T, rs3200401C>T, and rs6931097G>A in the key lncRNAs stimulating neuroapoptosis and neuroinflammation in PD, including HOTAIR, MALAT1, and lincRNA-P21, respectively, with susceptibility to PD as well as its clinical symptoms.The population of this study consisted of 240 individuals, including 120 controls and 120 cases, and the sample taken from them was peripheral blood. Genotyping of the target SNPs was done using PCR-RFLP. We found that the healthy individuals carry more T allele of MALAT1-rs3200401C>T compared to the patients (P= 0.019). Furthermore, it was observed that in the dominant genetic model, subjects with genotypes carrying the T allele have a lower risk of PD (OR= 0.530; CI= 0.296-0.950; P= 0.033). Regarding the lincRNA-P21-rs6931097G>A, we observed a significant protective relationship between its GA (OR= 0.144; CI= 0.030-0.680; P= 0.014) and AA (OR= 0.195; CI= 00.047-0.799; P= 0.023) genotypes with the manifestation of tremor and bradykinesia symptoms, respectively. Furthermore, the findings indicated that the minor TT genotype of HOTAIR-rs12826786C>T was significantly associated with a reduced risk of bradykinesia symptoms (OR= 0.147; CI= 0.039-0.555; P= 0.005). Collectively, these findings suggest that MALAT1-rs3200401C>T may be an important lncRNA SNP against the development of PD, while the other two SNPs show protective effects on the clinical manifestations of PD in a way that lincRNA-P21-rs6931097G>A has a protective effect against the occurrence of tremor and bradykinesia symptoms in PD patients, and HOTAIR -rs12826786C>T indicates a protective effect against the display of bradykinesia feature. Therefore, they can have valuable potential as biomarkers for clinical evaluations of this disease.

The multifaceted functions of long non-coding RNA HOTAIR in neuropathologies and its potential as a prognostic marker and therapeutic biotarget

Long non-coding RNAs (lncRNAs) are progressively being perceived as prominent molecular agents controlling multiple aspects of neuronal (patho)physiology. Amongst these is the HOX transcript antisense intergenic RNA, often abbreviated as HOTAIR. HOTAIR epigenetically regulates its target genes via its interaction with two different chromatin-modifying agents; histone methyltransferase polycomb-repressive complex 2 and histone demethylase lysine-specific demethylase 1. Parenthetically, HOTAIR elicits trans-acting sponging function against multiple micro-RNA species. Oncological research studies have confirmed the pathogenic functions of HOTAIR in multiple cancer types, such as gliomas and proposed it as a pro-oncological lncRNA. In fact, its expression has been suggested to be a predictor of the severity/grade of gliomas, and as a prognostic biomarker. Moreover, a propound influence of HOTAIR in other aspects of brain heath and disease states is just beginning to be unravelled. The objective of this review is to recapitulate all the relevant data pertaining to the regulatory roles of HOTAIR in neuronal (patho)physiology. To this end, we discuss the pathogenic mechanisms of HOTAIR in multiple neuronal diseases, such as neurodegeneration, traumatic brain injury and neuropsychiatric disorders. Finally, we also summarize the results from the studies incriminating HOTAIR in the pathogeneses of gliomas and other brain cancers. Implications of HOTAIR serving as a suitable therapeutic target in neuropathologies are also discussed.

Roles of HOTAIR Long Non-coding RNA in Gliomas and Other CNS Disorders

HOX transcript antisense intergenic RNA (HOTAIR) is a long non-coding RNA (lncRNA) which is increasingly being perceived as a tremendous molecular mediator of brain pathophysiology at multiple levels. Epigenetic regulation of target gene expression carried out by HOTAIR is thorough modulation of chromatin modifiers; histone methyltransferase polycomb repressive complex 2 (PRC2) and histone demethylase lysine-specific demethylase 1 (LSD1). Incidentally, HOTAIR was the first lncRNA shown to elicit sponging of specific microRNA (miRNA or miR) species in a trans-acting manner. It has been extensively studied in various cancers, including gliomas and is regarded as a prominent pro-tumorigenic and pro-oncogenic lncRNA. Indeed, the expression of HOTAIR may serve as glioma grade predictor and prognostic biomarker. The objective of this timely review is not only to outline the multifaceted pathogenic roles of HOTAIR in the development and pathophysiology of gliomas and brain cancers, but also to delineate the research findings implicating it as a critical regulator of overall brain pathophysiology. While the major focus is on neuro-oncology, wherein HOTAIR represents a particularly potent underlying pathogenic player and a suitable therapeutic target, mechanisms underlying the regulatory actions of HOTAIR in neurodegeneration, traumatic, hypoxic and ischemic brain injuries, and neuropsychiatric disorders are also presented.

Dissecting the Relationship Between Neuropsychiatric and Neurodegenerative Disorders

Neurodegenerative diseases (NDDs) and neuropsychiatric disorders (NPDs) are two common causes of death in elderly people, which includes progressive neuronal cell death and behavioral changes. NDDs include Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, multiple sclerosis, and motor neuron disease, characterized by cognitive defects and memory impairment, whereas NPDs include depression, seizures, migraine headaches, eating disorders, addictions, palsies, major depressive disorders, anxiety, and schizophrenia, characterized by behavioral changes. Mounting evidence demonstrated that NDDs and NPDs share an overlapping mechanism, which includes post-translational modifications, the microbiota-gut-brain axis, and signaling events. Mounting evidence demonstrated that various drug molecules, namely, natural compounds, repurposed drugs, multitarget directed ligands, and RNAs, have been potentially implemented as therapeutic agents against NDDs and NPDs. Herein, we highlighted the overlapping mechanism, the role of anxiety/stress-releasing factors, cytosol-to-nucleus signaling, and the microbiota-gut-brain axis in the pathophysiology of NDDs and NPDs. We summarize the therapeutic application of natural compounds, repurposed drugs, and multitarget-directed ligands as therapeutic agents. Lastly, we briefly described the application of RNA interferences as therapeutic agents in the pathogenesis of NDDs and NPDs. Neurodegenerative diseases and neuropsychiatric diseases both share a common signaling molecule and molecular phenomenon, namely, pro-inflammatory cytokines, γCaMKII and MAPK/ERK, chemokine receptors, BBB permeability, and the gut-microbiota-brain axis. Studies have demonstrated that any alterations in the signaling mentioned above molecules and molecular phenomena lead to the pathophysiology of neurodegenerative diseases, namely, Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis, and neuropsychiatric disorders, such as bipolar disorder, schizophrenia, depression, anxiety, autism spectrum disorder, and post-traumatic stress disorder.

Combining multi-omics approaches to prioritize the variant-regulated functional long non-coding RNAs in autism spectrum disorder

OBJECTIVE

Rising evidence has indicated that long non-coding RNA (lncRNA) may play an essential role in the development of autism spectrum disorder (ASD). However, identifying the lncRNAs associated with ASD and the risk loci on them remains a major challenge. This study aims to identify potential causative variants and explore the related mechanisms.

METHODS

By leveraging differential expression analysis, WGCNA analysis and cis-expression quantitative analysis, our study mined functional SNPs with the regulated long non-coding RNA genes in brain tissues. We recruited 611 ASD children and 645 healthy children in the case-control study.

RESULTS

Total 68 different expressed lncRNAs were validated by calculating the brain tissue-specific expression using RNA-seq data. By the WGCNA method, 9 functional lncRNAs classified as e-lncRNA were found to interact with 976 ASD risk genes. Furthermore, we mined functional SNPs regulated long non-coding RNAs in brain tissues. We analyzed the association between candidate SNPs and ASD risks in Chinese children, which showed BDNF-AS rs1565228 allele G to C reduced the risk of ASD (OR = 0.81, 95%CI: 0.66-0.98). Further bioinformatics analysis showed that the variant rs1565228 C>G with the low binding affinity of transcription factor SRF caused the decreased expression of lncRNA BDNF-AS. Our study revealed that rs2295412 in the non-coding sequence of the lncRNA gene region was significantly associated with the risk of ASD.

DISCUSSION

These findings suggested that the SNPs in the non-coding region of lncRNA may play important roles in the genetic susceptibility of ASD, which may facilitate the early screening of ASD.

Long noncoding RNA HOTAIR polymorphisms and susceptibility to bipolar disorder: a preliminary case-control study

Recent studies have shown that long noncoding RNAs contribute to the pathogenesis of bipolar disorder (BD). In this study, we genotyped four HOX Transcript Antisense Intergenic RNA (HOTAIR) gene polymorphisms to investigate if these variations could affect the risk of BD and its clinical subtypes. A total of 357 subjects, comprised of 194 BD patients and 163 age-matched healthy controls, were enrolled. Genotyping was carried out using PCR-RFLP and ARMS-PCR methods. We detected significant associations between the HOTAIR gene rs1899663 G/T, rs12826786 C/T, rs4759314 A/G, and rs920778 C/T polymorphism and the risk of BD under allelic, recessive, dominant, and codominant contrasted genetic models. The CT genotype of rs920778 C/T, GT genotype of rs1899663 G/T, and CT genotype of rs12826786 C/T polymorphisms enhanced the risk of BD type II (BDII). In contrast, the GG genotype of rs4759314 A/G polymorphism significantly diminished BDII risk by 83%. A positive association was noticed between CTTA and CTCG haplotypes of rs920778/rs1899663/rs12826786/rs4759314 and BD risk. Our findings reveal an interactive effect of HOTAIR polymorphisms on the development of BD and its subtypes. Further functional studies are needed to elucidate the role of these variations on HOTAIR expression and epigenetic status.

Emerging Role of Non-coding RNAs in Autism Spectrum Disorder

Autism spectrum disorders (ASD) embrace a diverse set of neurodevelopmental diseases with a multifaceted genetic basis. Non-coding RNAs (ncRNAs) are among putative loci with critical participation in the development of ASD. Expression of some lncRNAs, namely RP11-466P24.2, SYP-AS1, STXBP5-AS1, and IFNG-AS1 has been decreased in ASD, while AK128569, CTD-2516F10.2, MSNP1AS, RPS10P2-AS1, LINC00693, LINC00689, NEAT1, TUG1, and Shank2-AS lncRNAs have been over-expressed in ASD. Expression of several miRNAs which are implicated in the immunological developmental, immune responses, and protein synthesis as well as those participating in the regulation of PI3K/Akt/mTOR and EGFR signaling pathways is dysregulated in the context of ASD. In the present article, we describe investigations which appraised the role of lncRNAs, miRNAs, and circRNAs in the pathobiology of ASD.

The Epigenome in Neurodevelopmental Disorders

Neurodevelopmental diseases (NDDs), such as autism spectrum disorders, epilepsy, and schizophrenia, are characterized by diverse facets of neurological and psychiatric symptoms, differing in etiology, onset and severity. Such symptoms include mental delay, cognitive and language impairments, or restrictions to adaptive and social behavior. Nevertheless, all have in common that critical milestones of brain development are disrupted, leading to functional deficits of the central nervous system and clinical manifestation in child- or adulthood. To approach how the different development-associated neuropathologies can occur and which risk factors or critical processes are involved in provoking higher susceptibility for such diseases, a detailed understanding of the mechanisms underlying proper brain formation is required. NDDs rely on deficits in neuronal identity, proportion or function, whereby a defective development of the cerebral cortex, the seat of higher cognitive functions, is implicated in numerous disorders. Such deficits can be provoked by genetic and environmental factors during corticogenesis. Thereby, epigenetic mechanisms can act as an interface between external stimuli and the genome, since they are known to be responsive to external stimuli also in cortical neurons. In line with that, DNA methylation, histone modifications/variants, ATP-dependent chromatin remodeling, as well as regulatory non-coding RNAs regulate diverse aspects of neuronal development, and alterations in epigenomic marks have been associated with NDDs of varying phenotypes. Here, we provide an overview of essential steps of mammalian corticogenesis, and discuss the role of epigenetic mechanisms assumed to contribute to pathophysiological aspects of NDDs, when being disrupted.

Association of HOTAIR Polymorphisms with Susceptibility to Psoriasis in a Chinese Han Population

Psoriasis is a common disease in dermatology, but its etiology and pathogenesis have not been fully elucidated. In recent years, researchers have found that HOX transcript antisense RNA (HOTAIR) plays an important role in biological processes as an important long-chain noncoding RNA (lncRNA). The goal of this study was to investigate the association between HOTAIR polymorphisms and psoriasis in a Chinese Han population by screening key candidate single-nucleotide polymorphism (SNPs) sites in HOTAIR. A total of 269 patients diagnosed with psoriasis and 273 healthy control subjects were enrolled in this case-control study. Three SNPs of HOTAIR were genotyped: SNP1 (rs12826786), SNP2 (rs1899663), and SNP3 (rs4759314). All polymorphisms were in Hardy-Weinberg equilibrium in both the control and patient groups, and the SNPs were in linkage disequilibrium. The distribution of the rs4759314 genotype in the control group and case group was statistically significant according to all the models except the recessive model (adjusted p value < 0.05), and the CCG haplotype group had a significant difference (OR (95%CI) = 2.907 (1.344 - 6.289), adjusted p value = 0.0263). rs12826786 was associated with a risk of psoriasis according to the dominant model (C/T-T/T vs. C/C: OR (95%CI) = 0.70 (0.48 - 1.01), adjusted p value = 0.049) and overdominant model (C/T vs. C/C-T/T: OR (95%CI) = 0.69 (0.47 - 1.01), adjusted p value = 0.048). The current work showed that a genomic variant within HOTAIR was associated with a risk of psoriasis, and the clinical value of this study should be further evaluated in the future.

Genetic and molecular biology of autism spectrum disorder among Middle East population: a review

BACKGROUND

Autism spectrum disorder (ASD) is a neurodevelopmental disease, characterized by impaired social communication, executive dysfunction, and abnormal perceptual processing. It is more frequent among males. All of these clinical manifestations are associated with atypical neural development. Various genetic and environmental risk factors are involved in the etiology of autism. Genetic assessment is essential for the early detection and intervention which can improve social communications and reduce abnormal behaviors. Although, there is a noticeable ASD incidence in Middle East countries, there is still a lack of knowledge about the genetic and molecular biology of ASD among this population to introduce efficient diagnostic and prognostic methods.

MAIN BODY

In the present review, we have summarized all of the genes which have been associated with ASD progression among Middle East population. We have also categorized the reported genes based on their cell and molecular functions.

CONCLUSIONS

This review clarifies the genetic and molecular biology of ASD among Middle East population and paves the way of introducing an efficient population based panel of genetic markers for the early detection and management of ASD in Middle East countries.

Critical regulation of a NDIME/MEF2C axis in embryonic stem cell neural differentiation and autism

A microdeletion within human chromosome 5q14.3 has been associated with the occurrence of neurodevelopmental disorders, such as autism and intellectual disability, and MEF2C haploinsufficiency was identified as main cause. Here, we report that a brain-enriched long non-coding RNA, NDIME, is located near the MEF2C locus and is required for normal neural differentiation of mouse embryonic stem cells (mESCs). NDIME interacts with EZH2, the major component of polycomb repressive complex 2 (PRC2), and blocks EZH2-mediated trimethylation of histone H3 lysine 27 (H3K27me3) at the Mef2c promoter, promoting MEF2C transcription. Moreover, the expression levels of both NDIME and MEF2C were strongly downregulated in the hippocampus of a mouse model of autism, and the adeno-associated virus (AAV)-mediated expression of NDIME in the hippocampus of these mice significantly increased MEF2C expression and ameliorated autism-like behaviors. The results of this study reveal an epigenetic mechanism by which NDIME regulates MEF2C transcription and neural differentiation and suggest potential effects and therapeutic approaches of the NDIME/MEF2C axis in autism.

A single nucleotide polymorphism within HOX Transcript Antisense RNA (HOTAIR) is associated with risk of psoriasis

Recent studies have shown participation of long non-coding RNAs (lncRNAs) in the pathogenesis of psoriasis. Several mechanisms might be involved in the dysregulation of expression of lncRNAs in patients with psoriasis, among them is the presence of single nucleotide polymorphisms (SNPs) which modulate expression or function of these transcripts. In the present work, we genotyped three SNPs (rs12826786, rs1899663 and rs4759314) of the HOX Transcript Antisense RNA (HOTAIR) in 286 patients with psoriasis and 300 control subjects. The rs12826786 was associated with risk of psoriasis in dominant model (TC + TT vs. CC: OR (95% CI) = 1.59 (0.1.14-2.22), adjusted p-value = .02). In the allelic model, T allele of this SNP significantly increased the risk of psoriasis compared with the C allele (OR (95% CI) = 1.35 (1.06-1.71), adjusted p-value = .04). Other SNPs were not associated with risk of psoriasis in any inheritance model. No significant difference was found in haplotype frequencies between cases and controls. The current work shows association between a genomic variant within HOTAIR and risk of psoriasis. The clinical significance of this finding should be assessed in future studies.

Association Analysis Between the rs1899663 Polymorphism of HOTAIR and Risk of Psychiatric Conditions in an Iranian Population

Recent studies have shown contribution of long non-coding RNAs (lncRNAs) in the pathogenesis of a number of psychiatric disorders. In the current study, we investigated the association between a single nucleotide polymorphism in the lncRNA HOX transcript antisense intergenic RNA (HOTAIR) and risk of diverse neuropsychiatric conditions in Iranian population. The selected polymorphism (rs1899663) is an intronic variant of this lncRNA which has been associated with several cancers in different populations. This SNP was genotyped in 323 individuals with methamphetamine addiction, 55 children with attention-deficit hyperactive disorder (ADHD), 138 patients with bipolar disorder 1 (BPD1), 86 patients with BPD2, 53 patients with major depressive disorder (MDD), and 194 patients with schizophrenia (SCZ). There was no significant association between rs1899663 genotypes and risk of methamphetamine addiction or SCZ in any assessed inheritance model. There was a significant association between rs1899663 SNP and risk of BPD1 in allelic, co-dominant, and dominant models (P values of 0.003, 0.009, and 0.003, respectively). The T allele of this SNP conferred risk of BPD1 (OR (95% CI) = 1.70 (1.20-2.41)). This SNP was associated with risk of BPD2 in allelic and dominant models (P values of 0.02 and 0.04). The T allele of this SNP was revealed to be the risk allele for BPD2 as well (OR (95% CI) = 1.61 (1.09-2.40)). Besides, the mentioned SNP was associated with susceptibility to MDD in allelic and dominant models (P values of 0.01 and 0.03). Finally, the rs1899663 was associated with risk of ADHD in allelic, co-dominant, and dominant models (P values of 3.6E-4, 0.002, and 1.2E-4, respectively). The current investigation highlights the role of rs1899663 in conferring risk of BPD1, BPD2, MDD, and ADHD and suggests a similar underlying genetic background for these conditions.