Reactivation of a silenced H19 gene in human rhabdomyosarcoma by demethylation of DNA but not by histone hyperacetylation

BACKGROUND: The active copy of the imprinted gene H19 is turned off by inappropriate methylation in several pediatric tumors including Wilms' Tumour and embryonal rhabdomyosarcoma. H19 controls in cis the linked Insulin-like Growth Factor 2 (IGF2) gene, encoding an important growth factor. Recent work has suggested that methylation of a gene may lead to deacetylation of its associated histones and that silenced genes can be reactivated by increasing histone acetylation levels. RESULTS: Treatment of a rhabdomyosarcoma cell line which has a silent, methylated H19 gene with histone deacetylase (HDAC) inhibitors under conditions which gave maximal hyperacetylation of histone 4, both globally and at the H19 gene itself could not reactivate H19 or affect the active Insulin-like Growth Factor 2 (IGF2) gene, but caused clear up-regulation of the Tissue-type Plasminogen Activator (TPA) gene, a non-imprinted gene known to respond to changes in histone acetylation. In contrast, mild treatment of the cells with the methylation inhibitor 5-AzaC-2'-deoxycytidine (AzaC) on its own was able to reactivate H19. Combining AzaC treatment with HDAC inhibitors gave a reduced rather than enhanced reactivation. These findings were confirmed in mouse primary liver and kidney explants which maintain normal imprinting, where we also found that the silent Igf2 gene could not be reactivated by HDAC inhibitors. CONCLUSION: These results suggest that DNA methylation rather than histone acetylation is the primary determinant of silencing of H19 in rhabdomyosarcoma

Senescence Signatures Predict Hospitalization Risk and Severity in COVID-19 Patients

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in a global pandemic associated with substantial morbidity and mortality worldwide, with a particular risk for severe disease and mortality in the elderly population. The more aged you are the higher the risk for mortality and severity due to COVID-19. Why age is the single largest risk factor for severity in COVID-19 is not known. Together virus-induced cell senesence and aging are believed to play a central role in COVID-19 severity and pathogenesis. A deeper understanding of COVID-19 pathophysiology and the involvement of senescence/aging proteins is therefore required. This can help identify patients, at an earlier stage, who are more susceptible to acquiring a severe COVID-19 infection and those who are most likely to go on to develop post-COVID-19 syndrome. This early detection remains a major challenge however largely due to limited understanding of SARS-CoV-2 pathogenesis.In this study, we investigate whether the levels of senescence-specific plasma proteins from COVID-19 patients can be utilized to predict severity and post-COVID-19 syndrome. We performed proteomic profiling of plasma from COVID-19 patients (n = 400) using the Olink Explore 384 Inflammation Panel. Data analysis identified differences in plasma concentrations of proteins, which are linked to senescence while considering patient hospitalization status, age, and their World Health Organization (WHO) clinical progression score.The statistically significant changes were found in the senescence-associated plasma proteome of COVID-19 patients who were hospitalized, more aged, and those with severe WHO classification (TPPI, CXCL10, HGF, VEGFA, SIRPB1, IL-6, TNFRSF11B, and B4GALT1; p < 0.05) and which may be linked to post-COVID-19 syndrome. Epigenetic analysis of the methylome, using the GrimAge Clock, found that biological and chronological age did not correlate in hospitalized patients. We also identified that PTX3, CXCL10, KYNU, and SIRPB1 genes had increased promoter methylation in hospitalized patients.Machine learning analysis showed that characteristic protein changes perform with a similar accuracy to that of a whole panel biomarker signature in terms of hospitalization, age, and WHO clinical progression score.This study revealed senescence specific protein changes (sendotypes) in the plasma of COVID-19 patients, which can be used as determinants for predicting COVID-19 severity, viral signature persistence, and ultimately which may lead to post-COVID-19 syndrome. We propose that the identification of such sendotypes could be exploited for therapeutic intervention via senolytics in COVID-19

Placement during a Pandemic? : Exploring the Experiences & Perspectives of Students Completing Educational Placement during the COVID-19 Pandemic

The impact of the COVID-19 pandemic was felt on a global scale in nearly every aspect of life, but disruption was particularly observable within the sphere of education. Students engaged in initial teacher education at this time commonly experienced major upheavals within both their academic studies and their practical teaching placements in schools at the community level. This paper presents data collected from a small-scale study conducted at a higher education institution in Ireland and provides insights regarding students’ experiences of completing educational placement requirements in early childhood and primary school settings during the pandemic. A total of 204 participants took part in the study by responding to an online questionnaire. Findings revealed both the challenges and opportunities they faced in their own academic learning, the impact of public health regulations on their teaching practice and performance, and the challenges of work-life imbalance. These insights are examined considering previous research, and the paper concludes with suggestions for future practice