Expression analysis of DDC, dACE2, and EPO genes in Moroccan COVID-19 patients: links to viral load and demographics.

Introduction: Interactions between host and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are incompletely understood. Studies have highlighted the roles of L-dopa decarboxylase (DDC), interferon-inducible truncated isoform of angiotensin-converting enzyme 2 (dACE2), and immunomodulatory hypoxia-regulated gene erythropoietin (EPO) in viral infections. This study investigated the expression levels of DDC, dACE2, and EPO in 136 coronavirus disease 2019 (COVID-19) patients and 88 controls.

Methodology: Real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) was used to quantify mRNA levels of DDC, dACE2, and EPO; and the SARS-CoV-2 viral load in nasopharyngeal swabs.

Results: Significantly elevated levels of dACE2 (p = 0.003), DDC (p = 0.004), and EPO (p = 0.006) were observed in patients compared to controls. No correlation with the viral load (DDC: r = 0.12, p = 0.136; EPO: r = 0.02, p = 0.802; dACE2: r = 0.05, p = 0.491), and no associations with age or gender (all p > 0.05) were noted. There were positive correlations between DDC and dACE2 mRNA levels in infected (r = 0.31, p = 0.0002) and uninfected individuals (r = 0.25, p = 0.015); and between DDC and EPO in infected (r = 0.22, p = 0.008) and uninfected individuals (r = 0.27, p = 0.010). There was a positive correlation between dACE2 and EPO mRNA levels in both groups (infected: r = 0.22, p = 0.007; uninfected: r = 0.38, p = 0.0002).

Conclusions: DDC, dACE2, and EPO may contribute to COVID-19 pathogenesis through mechanisms independent of viral load, age, or gender.