scholarly journals Peer Review #3 of "The relative importance of DNA methylation and Dnmt2-mediated epigenetic regulation on Wolbachia densities and cytoplasmic incompatibility (v0.1)"

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Peiru Liu ◽  
Jing Zhang ◽  
Duo Du ◽  
Dandan Zhang ◽  
Zelin Jin ◽  
...  

Abstract Background Thoracic aortic dissection (TAD) is a severe disease with limited understandings in its pathogenesis. Altered DNA methylation has been revealed to be involved in many diseases etiology. Few studies have examined the role of DNA methylation in the development of TAD. This study explored alterations of the DNA methylation landscape in TAD and examined the potential role of cell-free DNA (cfDNA) methylation as a biomarker in TAD diagnosis. Results Ascending aortic tissues from TAD patients (Stanford type A; n = 6) and healthy controls (n = 6) were first examined via whole-genome bisulfite sequencing (WGBS). While no obvious global methylation shift was observed, numerous differentially methylated regions (DMRs) were identified, with associated genes enriched in the areas of vasculature and heart development. We further confirmed the methylation and expression changes in homeobox (Hox) clusters with 10 independent samples using bisulfite pyrosequencing and quantitative real-time PCR (qPCR). Among these, HOXA5, HOXB6 and HOXC6 were significantly down-regulated in TAD samples relative to controls. To evaluate cfDNA methylation pattern as a biomarker in TAD diagnosis, cfDNA from TAD patients (Stanford type A; n = 7) and healthy controls (n = 4) were examined by WGBS. A prediction model was built using DMRs identified previously from aortic tissues on methylation data from cfDNA. Both high sensitivity (86%) and specificity (75%) were achieved in patient classification (AUC = 0.96). Conclusions These findings showed an altered epigenetic regulation in TAD patients. This altered epigenetic regulation and subsequent altered expression of genes associated with vasculature and heart development, such as Hox family genes, may contribute to the loss of aortic integrity and TAD pathogenesis. Additionally, the cfDNA methylation in TAD was highly disease specific, which can be used as a non-invasive biomarker for disease prediction.


2021 ◽  
Author(s):  
Guillermo Barturen ◽  
Elena Carnero-Montoro ◽  
Manuel Martínez-Bueno ◽  
Silvia Rojo-Rello ◽  
Beatriz Sobrino ◽  
...  

SARS-CoV-2 causes a severe inflammatory syndrome called COVID-19 that primarily affects the lungs leading, in many cases, to bilateral pneumonia, severe dyspnea and in ~5% of the cases, death. The mechanisms through which this occurs are still being elucidated. A strong relationship between COVID-19 progression and autoimmune disorder pathogenesis has been identified as an exacerbated interferon immune response or an inflammatory condition mediated by an increase of pro-inflammatory cytokine production, among other. DNA methylation is known to regulate immune response processes, thus COVID-19 progression might be also conditioned by DNA methylation changes not studied in depth, yet. Thus, here an epigenome-wide DNA methylation analysis combined with DNA genotyping for 101 and 473 SARS-CoV-2 negative and positive lab tested individuals, respectively, from two different clinical centers is presented in order to evaluate the implications of the epigenetic regulation in the course of COVID-19 disease. The results reveal the existence of an epigenome regulation of functional pathways associated with the COVID-19 progression, such as innate interferon responses, hyperactivation of B and T lymphocytes, phagocytosis and innate C-type lectin DC-SIGN. These DNA methylation changes were found to be regulated by genetic loci associated with COVID-19 susceptibility and autoimmune disease. In mild COVID-19 patients hypomethylation of CpGs regulating genes within the AKT signaling pathway, and the hypermethylation of a group of CpGs related to environmental traits regulating IL-6 expression via the transcription factor CEBP, discriminate these individuals from those who develop the most critical outcomes of the disease. Thus, the analysis points out to an environmental contribution that mediated by DNA methylation changes in SARS-CoV-2 positive patients, might be playing a role in triggering the cytokine storm described in the most severe cases. In addition, important differences were found in terms of epigenetic regulation between severe and mild cases when compared with systemic autoimmune diseases.


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