Genetics and Epigenetics of Nasal Polyposis: A Systematic Review

Pre-asthma: a useful concept? A EUFOREA paper. Part 2-late onset eosinophilic asthma

The concept of pre-diabetes has led to provision of measures to reduce disease progression through identification of subjects at risk of diabetes. We previously considered the idea of pre-asthma in relation to allergic asthma and considered that, in addition to the need to improve population health via multiple measures, including reduction of exposure to allergens and pollutants and avoidance of obesity, there are several possible specific means to reduce asthma development in those most at risk (pre- asthma). The most obvious is allergen immunotherapy (AIT), which when given for allergic rhinitis (AR) has reasonable evidence to support asthma prevention in children (2) but also needs further study as primary prevention. In this second paper we explore the possibilities for similar actions in late onset eosinophilic asthma.

TAS2R38 Bitter Taste Receptor Polymorphisms in Patients with Chronic Rhinosinusitis with Nasal Polyps Preliminary Data in Polish Population

Chronic rhinosinusitis (CRS) affects 5-12% of the general population, and the most challenging patients are those with nasal polyposis (CRSwNP). Its complexity, unpredictability, and difficulties in selecting a treatment plan individually for each patient prompted scientists to look for possible genetic causes of this disease. It was proven that single nucleotide polymorphisms (SNPs) in the TAS2R38 gene may affect the mobility and the activity of the ciliated epithelium of the upper respiratory tract what can contribute to individual differences in susceptibility to CRS. There are two common haplotypes: a "protective" type (PAV), and a "non-protective" type (AVI). CRS patients who are homozygous PAV/PAV are considered as less susceptible to the severe course of the disease, whereas patients with AVI/AVI haplotype are more vulnerable. The aim of this study was to examine TAS2R38 gene polymorphisms among CRSwNP patients and control group (N = 544) with the evaluation of the association between the distribution of studied polymorphic variants and the incidence as well as severity of CRSwNP in the study group. Whole blood samples from CRSwNP patients (N = 106) and the control group (N = 438) were analyzed for alleles of the TAS2R38 gene using real-time PCR single nucleotide polymorphism genotyping assays for rs713598, rs1726866, and rs10246939. PAV (SG: 41%; CG: 49%) and AVI (SG: 59%; CG: 51%) haplotypes were the only ones detected in the study. The AVI haplotypes were 1.5 times more frequent in the study group than in the control group (p = 0.0204; OR = 1.43). AVI/AVI individuals tended to have more severe symptoms in the VAS scale, less QoL in the SNOT-22 test, and a bigger nasal obstruction upon endoscopic examination. Patients with PAV/PAV were twice more likely to have minor changes in preoperative CT scans (p = 0.0158; OR = 2.1; Fi = 0.24). Our study confirmed that the PAV/PAV diplotype might have some protective properties and carrying the AVI haplotype might predispose to the development of CRSwNP.

Genome-wide Epigenetic Study of Chronic Rhinosinusitis Tissues Reveals Dysregulated Inflammatory, Immunologic and Remodeling Pathways

BACKGROUND

Epigenetics studies mechanisms such as DNA methylation, histone modifications, non-coding RNAs, and alternative polyadenylation that can modify gene activity without changing the underlying DNA nucleotide base-pair structure. Because these changes are reversible, they have potential in developing novel therapeutics. Currently, seven pharmaceutical agents targeting epigenetic changes are FDA approved and commercially available for treatment of certain cancers. However, studies investigating epigenetics in chronic rhinosinusitis (CRS) have not been undertaken previously in the United States.

OBJECTIVES

The goal of this study was to investigate sinonasal DNA methylation patterns in CRS versus controls, to discern environmentally-induced epigenetic changes impacting CRS subjects.

METHODS AND RESULTS

Ethmoidal samples from CRS and inferior turbinate mucosal tissue samples from controls without CRS were studied. DNA methylation was studied by Reduced Representation Bisulfite Sequencing. RADMeth® biostatistical package was used to identify differentially methylated regions (DMRs) between CRS and controls. Ingenuity Pathway analysis of DMRs was performed to identify top upstream regulators and canonical pathways. Ninety-three samples from 64 CRS subjects (36 CRSwNP; 28 CRSsNP) and 29 controls were studied. CRS and control samples differed in 13 662 CpGs sites and 1381 DMRs. Top upstream regulators identified included: 1. CRS versus controls: TGFB1, TNF, TP53, DGCR8, and beta-estradiol. 2. CRSwNP versus controls: TGFB1, CTNNB1, lipopolysaccharide, ID2, and TCF7L2. 3. CRSsNP versus controls: MYOD1, acetone, ID2, ST8SIA4, and LEPR.

CONCLUSIONS

Differential patterns of methylation were identified between controls and CRS, CRSwNP, and CRSsNP. Epigenetic, environmentally-induced changes related to novel, inflammatory, immunologic, and remodeling pathways appear to affect epithelial integrity, cell proliferation, homeostasis, vascular permeability, and other yet uncharacterized pathways and genes.

Genetics and epigenetics of chronic rhinosinusitis

Discerning the genetics and epigenetics of chronic rhinosinusitis (CRS) may optimize outcomes through early diagnostics, personalized and novel therapeutics, and early prognostication. CRS associated with cystic fibrosis and primary ciliary dyskinesia has well-characterized genetic mutations. Most CRS subjects, however, do not exhibit identifiable monogenic alterations. Clustering in related individuals is seen in CRS with nasal polyps. Spouses of subjects with CRS without nasal polyps also may be at increased risk of the same disease. These observations generate questions on genetic and environmental influences in CRS. Genome-wide association studies have identified variations and polymorphisms between CRS and control subjects in genes related to innate and adaptive immunity. Candidate gene and transcriptomics studies have investigated and identified genetic variations related to immunity, inflammation, epithelial barrier function, stress-response, antigen processing, T-cell regulation, and cytokines in CRS. Epigenetic studies have identified mechanisms through which environmental factors may affect these gene functions. However, causality is not determined for most variations. Inferences drawn from these data must be measured because most investigations report unreplicated results from small study populations. Large, replicated studies in tight cohorts across diverse populations remain a pressing need in studying CRS genetics.

Epigenetic modifications in chronic rhinosinusitis with and without nasal polyps

Chronic rhinosinusitis (CRS) has brought a huge socioeconomic burden. However, its mechanism is still elusive, which may involve genetic, environmental and some other factors. Epigenetic analyses have been conducted to explore the mechanisms underlying CRS. Here, we reviewed the fruits in the epigenetic studies on DNA methylation, histone modification, and non-coding RNA regulation. We concluded that the epigenetic research on CRS has made great breakthroughs, especially in the past 5 years and the field of microRNAs. "Epigenetic therapies" are expected to be designed to treat CRS in the future.