Therapeutic Strategies of Clustered Regularly Interspaced Palindromic Repeats-Cas Systems for Different Viral Infections

Inhibition of HIV-1 replication using the CRISPR/cas9-no NLS system as a prophylactic strategy

Globally, it is estimated that 43 million people are living with human immunodeficiency virus type 1 (HIV-1), and there are more than 600,000 acquired immunodeficiency syndrome (AIDS)-related deaths in 2020. The only way to increase the life expectancy of these patients right now is to use combination antiretroviral therapy (cART) for the lifetime. Due to the integration of the HIV-1 DNA in lymphocytes, the replication of the virus can only be reduced by using antiretroviral drugs. If the drug is stopped, the virus will replicate and reduce the number of lymphocytes. In recent years, the clustered regularly interspaced short palindromic repeats (CRISPR)-associated endonuclease Cas9-mediated genome editing system has been considered, preventing HIV-1 replication by causing DNA double-stranded breaks (DSBs) or disrupting the integrated virus replication by targeting the provirus. In this study, we utilized the CRISPR/Cas9 without the nuclear localization signal sequence (w/o NLS) system to inhibit the VSV-G-pseudotyped HIV-1 replication by targeting the HIV-1 DNA as a prophylactic method. To this end, we designed a multiplex gRNA (guide RNA) cassette to target the pol, env, and nef/long terminal repeat (nef/LTR) regions of the HIV-1 genome and then cloned it in plasmid expressing no-NLS-Cas9 protein as an all-in-one CRISPR/Cas9 vector. Using HIV-1 pseudovirus transduction into HEK-293T cell lines, our results showed that the CRISPR/Cas9-no NLS system disrupts the pseudotyped HIV-1 DNA and significantly (P-value < 0.0001) decreases the p24 antigen shedding and viral RNA load in cell culture supernatants harvested 48h after virus transduction. Although these results revealed the potential of the CRISPR/Cas9-no NLS nuclease system as a prophylactic strategy against HIV-1 infections, due to inefficient impairments of HIV-1 DNA, further studies are required to enhance its effectiveness and application in clinical practice.

The interplay between viruses and TRIM family proteins

Novel therapeutic options are urgently needed to improve the global treatment of viral infections. Tripartite motif (TRIM) family proteins are involved in various biological and cellular functions including differentiation, development, proliferation, oncogenesis, innate immunity, and viral autophagy. Various TRIM proteins show antiviral properties against different viral infections and are now transitioning from ubiquitin proteins to an efficient and emerging therapeutic class of proteins. TRIM proteins combat viruses by targeting them at pre/post transcription levels. This review summarizes the comprehensive roles of different TRIM proteins along with their expression systems and their applications towards antiviral therapeutics.