MicroRNA-Mediated Regulation of the Virus Cycle and Pathogenesis in the SARS-CoV-2 Disease.

In the last few years, microRNA-mediated regulation has been shown to be important in viral infections. In fact, viral microRNAs can alter cell physiology and act on the immune system; moreover, cellular microRNAs can regulate the virus cycle, influencing positively or negatively viral replication. Accordingly, microRNAs can represent diagnostic and prognostic biomarkers of infectious processes and a promising approach for designing targeted therapies. In the past 18 months, the COVID-19 infection from SARS-CoV-2 has engaged many researchers in the search for diagnostic and prognostic markers and the development of therapies. Although some research suggests that the SARS-CoV-2 genome can produce microRNAs and that host microRNAs may be involved in the cellular response to the virus, to date, not enough evidence has been provided. In this paper, using a focused bioinformatic approach exploring the SARS-CoV-2 genome, we propose that SARS-CoV-2 is able to produce microRNAs sharing a strong sequence homology with the human ones and also that human microRNAs may target viral RNA regulating the virus life cycle inside human cells. Interestingly, all viral miRNA sequences and some human miRNA target sites are conserved in more recent SARS-CoV-2 variants of concern (VOCs). Even if experimental evidence will be needed, in silico analysis represents a valuable source of information useful to understand the sophisticated molecular mechanisms of disease and to sustain biomedical applications.

Acute GVHD classification based on the dynamics of GVHD skin involvement from its appearance to the start of systemic treatment.

We conducted a prospective study aimed at investigating the prognostic value of the dynamic of a-GVHD progression from cutaneous to visceral involvement. In 108 consecutive patients who underwent allogeneic HSCT, we classified a-GVHD according to a "GHVD skin dynamic": 18/82 patients started Corticosteroid (CS) within 48 h (Group 1); 13/82 started CS within days 3-7 (Group 2); Group 3A (n 31) was defined when Skin GVHD Overall Grade 1, left untreated for 1 week, showed an increase in involved body surface area <5 %; Group 3B (n 20), was defined when Skin GVHD Overall Grade 1, left untreated at 1 week, had an increase in involved body surface area >5%. These four groups had distinctive 2-y OS. Patients could be then grouped into "poor risk" (Group 1 and Group 3B) and "good risk" (Group 2 and Group 3A). "Poor risk" had inferior OS in univariate and multivariate analysis, (HR 2.222; 95% CL: 1.017-4.855; p 0.04). Among the patients with skin-only Grade 1 GVHD, subgroup 3A had an OS of 75.1% versus 39.8% found in subgroup 3B (p = 0.03). The dynamic of skin GVHD may be used to classify a-GVHD and guide treatment in Overall Grade 1 skin-only GVHD.