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Biology subjects

Makinson, A.

Publications and source records attributed to Makinson, A..

2 recordsLinked to original sources

A new HIV-1 latency reversing agent activating HIV-Tat

Despite its efficiency to prevent viral multiplication, antiretroviral therapy does not affect HIV-1 latently-infected cells. These cells do not produce significant amounts of viruses and constitute HIV-1 reservoir. To purge this long-lived viral reservoir, the "shock and kill" strategy relies on the use of latency reversing agents (LRAs) to induce activation of latent cells. All LRAs developed until now target cellular proteins and are therefore not specific for HIV-infected cells. Here we present a new LRA that binds and activates HIV-1 Tat which is the key regulator for viral transcription and latency reversal. This molecule termed D10 was designed to bind to the major groove of the Tat protein, and found to activate Tat transcriptional activity by stabilizing the HIV transcription complex. This LRA induces strong HIV production by latent cell lines and latent cells from people living with HIV-1. On latent cells from PBMCs, D10 is active at [~]50 nM, the concentration required to stabilize HIV transcription complex. D10 is the first Tat activator available and the first LRA that targets an HIV protein.

microbiology↗

Low selectivity index of ivermectin and macrocyclic lactones on SARS-CoV2 replication in vitro argues against their therapeutic use for COVID-19.

There are very limited antiviral therapeutic options for coronavirus infections, therefore global drug re-purposing efforts are paramount to identify available compounds that could provide clinical benefits to patients with COVID-19. Ivermectin was first approved for human use as an endectocide in the 1980s. It remains one of the most important global health medicines in history and has recently been shown to exert in vitro activity against SARS-CoV-2. However, the macrocyclic lactone family of compounds has not previously been evaluated for activity against SARS-CoV-2. The present study aims at comparing their anti-viral activity in relevant pulmonary cell lines in vitro. Here, in vitro antiviral activity of the avermectins (ivermectin and selamectin) and milbemycins (moxidectin and milbemycin oxime) were assessed against a clinical isolate from a CHU Montpellier patient infected with SARS-CoV-2 in 2020. Ivermectin demonstrated anti-SARS-CoV-2 activity in vitro in human pulmonary cells in comparison to VeroE6 (with EC50 of 1-3 M). Similarly, the other macrocyclic lactones moxidectin, milbemycin oxime and selamectin reduced SARS-CoV-2 replication in vitro (with EC50 of 2-5 M). Immunofluorescence assays with ivermectin and moxidectin showed a reduction in the number of infected and polynuclear cells suggesting a drug action on viral cell fusion. However, cellular toxicity of the avermectins and milbemycins during infection showed a very low selectivity index <10 for all compounds. In conclusion, none of these agents appears suitable for human use for its anti-SARS-CoV-2 activity per se, due to low selectivity index. This is discussed in regards to recent clinical COVID studies on ivermectin.

microbiology↗