RESUMEN
Background: COVID-19 causes significant morbidity and mortality, albeit with considerable heterogeneity among affected individuals. It remains unclear which host factors determine disease severity and survival. Given the propensity of clonal hematopoiesis (CH) to promote inflammation in healthy individuals, we investigated its effect on COVID-19 outcomes. Method(s): We performed a multi-omics interrogation of the genome, epigenome, transcriptome, and proteome of peripheral blood mononuclear cells from COVID-19 patients (n=227). We obtained clinical data, laboratory studies, and survival outcomes. We determined CH status and TET2-related DNA methylation. We performed single-cell proteogenomics to understand clonal composition in relation to cell phenotype. We interrogated single-cell gene expression in isolation and in conjunction with DNA accessibility. We integrated these multi-omics data to understand the effect of CH on clonal composition, gene expression, methylation of cis-regulatory elements, and lineage commitment in COVID-19 patients. We performed shRNA knockdowns to validate the effect of one candidate transcription factor in myeloid cell lines. Result(s): The presence of CH was strongly associated with COVID-19 severity and all-cause mortality, independent of age (HR 3.48, 95% CI 1.45-8.36, p=0.005). Differential methylation of promoters and enhancers was prevalent in TET2-mutant, but not DNMT3A-mutant CH. TET2- mutant CH was associated with enhanced classical/intermediate monocytosis and single-cell proteogenomics confirmed an enrichment of TET2 mutations in these cell types. We identified celltype specific gene expression changes associated with TET2 mutations in 102,072 single cells (n=34). Single-cell RNA-seq confirmed the skewing of hematopoiesis towards classical and intermediate monocytes and demonstrated the downregulation of EGR1 (a transcription factor important for monocyte differentiation) along with up-regulation of the lncRNA MALAT1 in monocytes. Combined scRNA-/scATAC-seq in 43,160 single cells (n=18) confirmed the skewing of hematopoiesis and up-regulation of MALAT1 in monocytes along with decreased accessibility of EGR1 motifs in known cis-regulatory elements. Using myeloid cell lines for functional validation, shRNA knockdowns of EGR1 confirmed the up-regulation of MALAT1 (in comparison to wildtype controls). Conclusion(s): CH is an independent prognostic factor in COVID-19 and skews hematopoiesis towards monocytosis. TET2-mutant CH is characterized by differential methylation and accessibility of enhancers binding myeloid transcriptions factors including EGR1. The ensuing loss of EGR1 expression in monocytes causes MALAT1 overexpression, a factor known to promote monocyte differentiation and inflammation. These data provide a mechanistic insight to the adverse prognostic impact of CH in COVID-19.
RESUMEN
The purpose of this study was to determine the impact of the Restricted Movement Order (RMO) due to COVID-19 to March - July 2020 semester students of Universiti Teknologi MARA (UiTM) Malacca. Through a confirmatory factor analysis, the student understanding scale was validated in three dimensions: technology acceptance, teaching approach and student readiness in the practice of Open and Distance Learning (ODL). The article also analysed the relationship between student understanding and the three variables. A total of 370 respondents had been selected using purposive sampling method using SPSS analysis. The result showed that there is a weak relationship between teaching approach and student understanding with the correlation of 0.355. It is followed by the moderate relationship between teaching approach and student understanding with the correlation of 0.613. Meanwhile, student readiness and student understanding have been identified as a very strong relationship with the correlations of 0.743. The findings also found that student readiness has the highest mean as compared to other factors. This result specified that the students of UiTM Melaka are not fully prepared mentally and physically for an inclusive ODL approach. They felt that ODL is very incumbering and difficult in understanding the content of learning sessions especially for the subjects related with calculations. © 2021 Karadeniz Technical University. All rights reserved.