Association of endometriosis with Sjögren's syndrome: Genetic insights (Review).

Patients with a history of endometriosis have an increased risk of developing various autoimmune diseases such as rheumatoid arthritis, ankylosing spondylitis, systemic lupus erythematosus, multiple sclerosis and celiac disease. There is a potential association between endometriosis and an increased susceptibility for Sjögren's syndrome (SS). SS is a common chronic, inflammatory, systemic, autoimmune, multifactorial disease of complex pathology, with genetic, epigenetic and environmental factors contributing to the development of this condition. It occurs in 0.5­1% of the population, is characterized by the presence of ocular dryness, lymphocytic infiltrations and contributes to neurological, gastrointestinal, vascular and dermatological manifestations. Endometriosis is an inflammatory, estrogen­dependent, multifactorial, heterogeneous gynecological disease, affecting ≤10% of reproductive­age women. It is characterized by the occurrence of endometrial tissue outside the uterine cavity, mainly in the pelvic cavity, and is associated with pelvic pain, dysmenorrhea, deep dyspareunia and either subfertility or infertility. It is still unclear whether SS appears as a secondary response to endometriosis, or it is developed due to any potential shared mechanisms of these conditions. The aim of the present review was to explore further the biological basis only of the co­occurrence of these disorders but not their association at clinical basis, focusing on the analysis of the partially shared genetic background between endometriosis and SS, and the clarification of the possible similarities in the underlying pathogenetic mechanisms and the relevant molecular pathways.

Genetic factors involved in the co­occurrence of endometriosis with ankylosing spondylitis (Review).

Previous research has revealed an association between endometriosis and various autoimmune diseases, while recent data suggest, for the first time, an association between endometriosis and the risk of developing ankylosing spondylitis (AS). AS, the prototype of spondyloarthritides diseases, is a systemic, chronic, immune­mediated inflammatory arthritis, which primarily affects the spine and sacroiliac joints, as well as the axial skeleton with or without extraspinal manifestations. AS is of polygenic inheritance and numerous immunologically relevant genes contribute to its development. Endometriosis is an enigmatic, relatively common, benign, estrogen­dependent, heterogeneous gynecological disease, influenced by multiple genetic, epigenetic and environmental factors. It is characterized by the growth of endometrial tissue occurring in sites other than the uterine cavity, most commonly in the pelvic cavity, including the ovaries and the uterosacral ligaments, affecting up to 10% of the female population of childbearing age, causing pain and infertility. The present review discusses whether a partially shared genetic background may explain the co­occurrence of these disorders, as well as potential similarities regarding the underlying pathogenetic mechanisms and specific molecular and cellular pathways.

Association of endometriosis with cardiovascular disease: Genetic aspects (Review).

Cardiovascular disease (CVD) comprises a broad spectrum of pathological conditions that affect the heart or blood vessels, including sequelae that arise from damaged vasculature in other organs of the body, such as the brain, kidneys or eyes. Atherosclerosis is a chronic inflammatory disease of the arterial intima and is the primary cause of coronary artery disease, peripheral vascular disease, heart attack, stroke and renal pathology. It represents a leading cause of mortality worldwide and the loss of human productivity that is marked by an altered immune response. Endometriosis is a heritable, heterogeneous, common gynecological condition influenced by multiple genetic, epigenetic and environmental factors, affecting up to 10% of the female population of childbearing age, causing pain and infertility; it is characterized by the ectopic growth of endometrial tissue outside the uterine cavity. Of note, epidemiological data obtained thus far have suggested a link between endometriosis and the risk of developing CVD. The similarities observed in specific molecular and cellular pathways of endometriosis and CVD may be partially explained by a shared genetic background. The present review presents and discusses the shared genetic factors which have been reported to be associated with the development of both disorders.

Is the Association of the Rare rs35667974 IFIH1 Gene Polymorphism With Autoimmune Diseases a Case of RNA Epigenetics?

Interferon induced with helicase C domain-containing protein 1 (IFIH1) gene encodes a cytoplasmic RNA helicase otherwise known as melanoma differentiation-associated 5 (MDA5), a RIG-1-like RNA helicase that recognizes viral RNA and is involved in innate immunity through recognition of viral RNA. Upon binding to double-stranded (ds) RNA, MDA5 forms a filamentous assembly along the length of dsRNA and utilizes molecular signatures to discriminate self, versus non-self on the basis of dsRNA length and methylation. Its missense variant rs35667974 is protective for type 1 diabetes, psoriasis, and psoriatic arthritis, but is also found to be associated with an increased risk for ankylosing spondylitis, Crohn's disease, and ulcerative colitis. To gain insight into the complex role of this variant we performed a structural analysis of MDA5 in complex with dsRNA using molecular dynamics simulations. Our data suggest that while the Ile923Val mutation of the rs35667974 variant does not affect binding to native dsRNA significantly, it displays a destabilizing effect in the presence of 2'-O uridine methylation. Thus, the presence of 2'-O-methylation at the dsRNA introduces a sensing signature that leads to selective reduction of the overall MDA catalytic activity. This study represents an evaluation of the role of the shared rs35667974 variant of autoimmune locus IFIH1, reported to lead to selectively reduced catalytic activity of the modified MDA5 phenotype and, as a consequence, reduced negative feedback on cytokine and chemokine signaling and selectively protection against autoimmunity.

Role of non­coding RNAs as biomarkers and the application of omics technologies in Alzheimer's disease (Review).

Alzheimer's disease (AD) is a neurodegenerative disorder that has a significant association with age. Despite its increasing incidence in the population, the etiology of the disease remains poorly understood, and there are currently no effective treatments readily available. The main genes that are associated with AD are the amyloid precursor protein, presenilin­1 and presenilin­2, as well as the apolipoprotein E gene. In addition to genetic factors, a wide range of environmental and lifestyle factors are equally characterized as risk factors for the development of AD, while non­coding RNAs (ncRNAs) and other epigenetic mechanisms play a key role in their detrimental effects. Multiple types of ncRNAs, such as microRNAs, circular RNAs, Piwi­interacting RNAs and long non­coding RNAs are being increasingly implicated in AD. Alterations in ncRNAs can be detected in cerebrospinal fluid, as well in as the brain, highlighting these as promising biomarkers for the detection and treatment of AD. Developments in high­throughput technologies have led to the so­called 'omics' era, which involves the collection of big data and information at both molecular and protein levels, while combining the development of novel computational and statistical tools capable of analyzing and filtering such data. The present review discusses the role of ncRNAs and their use as biomarkers for AD, and summarizes the findings from the application of omics technologies in AD.

Role of microRNAs and long non­coding RNAs in glucocorticoid signaling (Review).

The synthesis and release of glucocorticoids in living organisms are related to their response to unfavorable stressful conditions in order to maintain homeostatic functions and survive. One such hormone in humans is cortisol, which is produced by the hypothalamic­pituitary­adrenal cortex axis and binds with the glucocorticoid receptor (GR) following its secretion. GR controls a number of distinct gene networks. Non­coding RNAs (ncRNAs), such as microRNAs (miRNAs) and long non­coding RNAs (lncRNAs), regulate the expression and function of GR, having a considerable impact on various biological processes and treatment approaches for numerous disorders. In the present review, the GR pathways and signaling as part of the stress response system are discussed. A detailed report on the role of miRNAs and lncRNAs in glucocorticoid signaling is also presented.

Long non­coding RNAs and microRNAs as regulators of stress in cancer (Review).

Resistance to stress is a feature of cancer cells. Cellular stress includes oxidative, metabolic and genotoxic stress conditions, which under normal conditions lead to cell death. However, in contrast to normal cells, cancer cells overcome the checkpoints that normally restrict growth, and are able to resist cellular stress and subsequent cell death through a variety of mechanisms, which include several non­coding RNAs (ncRNAs). Within this context, long ncRNAs (lncRNAs) and microRNAs (miRNAs/miRs) are the main categories of ncRNAs that have been shown in the literature to function as regulators of stress resistance pathways in cancer. miRNAs play a key role in the majority of biological pathways, as they regulate the expression of hundreds of target genes, including genes involved in stress response and cell death, oncogenes, or tumor suppressor genes, by inhibiting protein translation or promoting the degradation of mRNAs. Respectively, lncRNAs are epigenetic regulators, which are also involved in cancer progression, stress response and metabolic pathways by promoting or inhibiting the transcription, splicing, translation and modulation of protein function. Thus, the present review summarizes recent knowledge related to the role of these molecules in the cancer response to stress, highlighting the ability of these non­coding molecules to be effective drug targets and biomarkers in cancer treatment.

Functional significance of the rare rs35667974 IFIH1 gene polymorphism, associated with multiple autoimmune diseases, using a structural biological approach.

Autoimmune diseases, which affect approximately 5% of human population, are a range of diseases in which the immune response to self-antigens results in damage or dysfunction of tissues. Recent genome wide association studies (GWAS) have successfully identified novel autoimmune disease-associated loci, with many of them shared by multiple disease-associated pathways but much of the genetics and pathophysiological mechanisms remain still obscure. Considering that most of the potential causal variants are still unknown, many studies showed that the missense variant rs35667974 at interferon-induced with helicase C domain 1 (IFIH1) gene is protective for type 1 diabetes (T1D), psoriasis (PS) and psoriatic arthritis (PsA). Recently, this variant was found to be also associated with ankylosing spondylitis (AS), Crohn's disease (CD) and ulcerative colitis (UC). The IFIH1 gene encodes a cytoplasmic RNA helicase otherwise known as melanoma differentiation-associated 5 (MDA5) that recognizes viral RNA and is involved in innate immunity through recognition of viral RNA. In the present study we sought to investigate the association of the rare rs35667974 variant of IFIH1 gene, which resides in exon 14 and changes a conserved isoleucine at position #923 to valine, in the development of various autoimmune diseases and give a reason for the selectivity affecting different autoimmune diseases. Evolutionary studies and three-dimensional (3 D) homology modelling were employed on the MDA5 protein product, through its association with dsRNA, recognition factor controlling cytokine and chemokine signalling, to investigate the protective role of the MDA5 variant for certain autoimmune diseases.

C1q Gene Polymorphism Is Associated with Asymptomatic Bacteriuria in Patients with Type 2 Diabetes Mellitus.

Background and Objectives: Asymptomatic bacteriuria (ASB) appears to have a higher prevalence in diabetics and has been associated with various genetic polymorphisms of the innate immune system. Single nucleotide polymorphisms (SNPs) of the C1q gene that encodes for the trigger molecule of the classical complement pathway increase the risk of bacterial infections as well as other diseases. In the present study, we sought to investigate the association of C1q rs292001 (G > A) SNP with ASB in patients with type 2 diabetes (T2D). Materials and Methods: In this case-control study, performed at the University and the Venizeleion General Hospital of Heraklion, Crete, Greece, 75 adult male and female Cretan patients with T2D and ASB and 75 adult male and female Cretan patients with T2D but without ASB were enrolled and genotyped for rs292001 SNP of C1q gene. Genetic analysis was based on the polymerase chain reaction (PCR) and restriction fragment length polymorphisms (RLFPs) methods. Results: Τhe frequency of homozygotes for the G/G genotype of C1q rs292001 was significantly higher in patients with T2D and ASB than in the control group (p-value = 0.0480, OR = 2.952, 95% CI: 1.052−7.542). Conclusions: Τhe present study provides the first evidence of an association between the C1q rs292001 SNP and an increased susceptibility for ASB in an adult Cretan population with T2D, thus suggesting that this SNP can be encountered as a risk factor for the presence of ASB in patients with T2D.

Increased risk of rheumatoid arthritis in patients with endometriosis: genetic aspects.

RA is an inflammatory joint disease of an autoimmune nature, with a complex mode of inheritance characterized by chronic and destructive inflammation in the peripheral joints of the hands and feet and irreversible disability. This disorder occurs more often in women, and reproductive and hormonal factors have been shown to be related to increased risk. Endometriosis is a chronic, complex, oestrogen-dependent and progressive gynaecological disorder characterized by the growth of endometrial tissue outside the uterine cavity. Thus far, substantial abnormalities in the immune system of women with endometriosis have been demonstrated. Epidemiological data have suggested a link between endometriosis and the risk of incident RA. The similarities between molecular and cellular pathways of endometriosis and RA may implicate a partially shared genetic background. In this review we present an overview of the shared genetic factors known thus far that are associated with the development of both disorders.