Reply to 'COVID-19 severity, miR-21 targets, and common human genetic variation'

COVID-19 in patients with anemia and haematological malignancies: risk factors, clinical guidelines, and emerging therapeutic approaches

Extensive research in countries with high sociodemographic indices (SDIs) to date has shown that coronavirus disease 2019 (COVID-19) may be directly associated with more severe outcomes among patients living with haematological disorders and malignancies (HDMs). Because individuals with moderate to severe immunodeficiency are likely to undergo persistent infections, shed virus particles for prolonged periods, and lack an inflammatory or abortive phase, this represents an overall risk of morbidity and mortality from COVID-19. In cases suffering from HDMs, further investigation is needed to achieve a better understanding of triviruses and a group of related variants in patients with anemia and HDMs, as well as their treatment through vaccines, drugs, and other methods. Against this background, the present study aimed to delineate the relationship between HDMs and the novel COVID-19, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Besides, effective treatment options for HDM cases were further explored to address this epidemic and its variants. Therefore, learning about how COVID-19 manifests in these patients, along with exploiting the most appropriate treatments, may lead to the development of treatment and care strategies by clinicians and researchers to help patients recover faster. Video Abstract.

Hybridization chain reaction circuit controller: CRISPR/Cas12a conversion amplifier for miRNA-21 sensitive detection

MicroRNA (miRNA) is crucial to the diagnose of various diseases. However, the accurate detection of miRNA has been challenging due to its short length and low abundance. Here, we designed a hybridization chain reaction (HCR) circuit controller to initiate the CRISPR/Cas12a conversion amplifier (HCR-Cas12a controller) for sensitive detection of miRNA-21 (miR-21). In the HCR, pre-crRNA was encapsulated in a hairpin structure until the miR-21 was present. Afterward, Cas12a fully exerted its RNase activity to self-mature pre-crRNA. Then, the trans-cleavage activity of Cas12a was initiated by activator. This results in the conversion of biological signals to fluorescent signal. During HCR-Cas12a controller, the circuit formed quickly, while the Cas12a system worked in a short time. The miR-21 was ultra-sensitively detected with the wide detection range of 1 fM - 100 nM, and the calculated limit of detection was 75.4 aM. The sensitivity was an order of magnitude lower than the standard method. The formation of HCR at room temperature does not require a thermal cycler. Additionally, Cas12a can work without the need for precise or expensive instruments. Therefore, our proposed method was suitable for low-resource settings, and provided a technical basis for sensitive detection of miRNA in low concentration range.

Role of circulatory miRNA-21 and associated signaling pathways in the pathogenesis of pulmonary fibrosis among individuals recovered after COVID-19 infection

Introduction

Currently pulmonary fibrosis in post-COVID individuals represents a crucial milieu of investigation due to long-term associated complications and worse clinical outcome. Lack of studies in Indian population confers a crucial need for elucidating possible targets and mechanisms to explore better management and outcome. Hence, this study aimed to explore the role of circulating miRNA-21 in patients from South India after COVID-19 recovery, while targeting TGF-β signaling pathway involved in the development of pulmonary fibrosis.

Methods

This prospective, single centre, hospital-based study enrolled a total of 50 participants in the age group of 50 to 60 years including 25 non-infected controls and 25 patients who were recovered after 3–6 months of COVID-19 infection and presented radiological pulmonary abnormalities. Quantification of miRNA-21 and selected gene transcripts (TGF-β, Col1A2, Col3A1, and α-SMA) was performed in plasma samples of both patients and controls.

Results

Significantly increased expression levels of miRNA-21 was observed in patient samples compared to controls (4.50 ± 1.03 vs 12.60 ± 3.52, p < 0.0001) with 72.10% sensitivity and 80.10% specificity. Further, significantly increased levels of central fibrosis regulatory gene transcript TGF-β (0.56 ± 0.27 vs 1.83 ± 0.98), two crucial collagen transcripts Col1A2 (0.62 ± 0.19 vs 1.56 ± 1.00) and Col3A1 (0.61 ± 0.27 vs 1.54 ± 0.89), and α-SMA (0.46 ± 0.17 vs 1.20 ± 0.78) was observed in patients compared to controls. Western-blot analysis also showed almost similar observations at proteins levels.

Conclusion

Circulating miRNA-21 may provide crucial insights for elucidating TGF-β mediated pulmonary remodeling involved in the fibrosis development and achieve better clinical outcome for post-COVID patients after recovery, in real-time with high diagnostic accuracy.

Non-coding RNA in SARS-CoV-2: Progress toward therapeutic significance

The recently developed pathogenic virus, SARS-CoV-2, was found in the Hubei Province, China. Giving rise to a broad spectrum of symptoms, SARS-CoV-2 rapidly spread across the globe, causing multi-systemic and dangerous complications, with death in extreme cases. Thereby, the number of research cases increases every day on preventing infection and treating its resulting damage. Accumulating evidence suggests noncoding RNAs (ncRNAs) are necessary for modifying virus infection and antiviral immune reaction, along with biological processes regulating SARS-CoV-2 and subsequent disease states. Therefore, understanding these mechanisms might provide a further understanding of the pathogenesis and feasible therapy alternatives against SARS-CoV2. Consequently, the molecular biology of SARS-CoV-2, ncRNA's role in its infection, and various RNA therapy tactics against the virus have been presented in this review section.