Role of MicroRNAs in Establishing Latency of Human Immunodeficiency Virus.

Acquired immunodeficiency syndrome (AIDS) emerged as an epidemic in Africa in 1981, and now it has become a most destructive global pandemic. Human immunodeficiency virus (HIV) is responsible for the pathogenesis of AIDS, and it is usually transmitted through unsafe sexual activities. HIV is a lentivirus that can remain latent in the host cells for a long period, and it has various mechanisms to establish latency. The HIV genome encodes several microRNAs (miRNA-TAR, miRNA-H1, miRNA-H3, and miRNA-Nef-367) that act as posttranscriptional control by targeting mRNA sequences. The miRNA-TAR, miRNA-Nef-367, and miRNA-H1 have established roles in HIV latency, whereas miRNA-H3 can activate the latent reservoirs of HIV. The human genome also encodes several miRNAs that have defensive roles against infections. Cellular miRNAs (miRNA-29a, miRNA-146a, miRNA-34c-5'p, miRNA-186, miRNA-210 and miRNA-222) also contribute to viral latency. The most challenging hurdle in the development of effective HIV therapeutics is viral latency. A complete understanding of latency will enable us to develop efficient therapeutics and to eradicate HIV from the globe.

Immune-related therapeutics: an update on antiviral drugs and vaccines to tackle the COVID-19 pandemic.

The coronavirus disease 2019 (COVID-19) pandemic rapidly spread globally. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes COVID-19, is a positive-sense single-stranded RNA virus with a reported fatality rate ranging from 1% to 7%, and people with immune-compromised conditions, children, and older adults are particularly vulnerable. Respiratory failure and cytokine storm-induced multiple organ failure are the major causes of death. This article highlights the innate and adaptive immune mechanisms of host cells activated in response to SARS-CoV-2 infection and possible therapeutic approaches against COVID-19. Some potential drugs proven to be effective for other viral diseases are under clinical trials now for use against COVID-19. Examples include inhibitors of RNA-dependent RNA polymerase (remdesivir, favipiravir, ribavirin), viral protein synthesis (ivermectin, lopinavir/ ritonavir), and fusion of the viral membrane with host cells (chloroquine, hydroxychloroquine, nitazoxanide, and umifenovir). This article also presents the intellectual groundwork for the ongoing development of vaccines in preclinical and clinical trials, explaining potential candidates (live attenuated-whole virus vaccines, inactivated vaccines, subunit vaccines, DNAbased vaccines, protein-based vaccines, nanoparticle-based vaccines, virus-like particles and mRNA-based vaccines). Designing and developing an effective vaccine (both prophylactic and therapeutic) would be a long-term solution and the most effective way to eliminate the COVID-19 pandemic.