Monday, July 26, 2010

A lab, a plant, a compound ten times more powerful than prostratin?

The Man: José Alcami

The Plant: Euphorbia (one of many types of Euphorbia)

Interview with José Alcami, from the the Instituto de Salud Carlos III in Madrid
Interview conducted on July 17, 2010 at the "Toward a Cure" HIV Reservoirs Workshop, Vienna, Austria

AIDS Policy Project: Thanks so much for sitting down with us. Tell us about your work.

I work in Spain in a basic research lab*. We study the mechanism of HIV latency and re-activation--we want to understand why and how the virus can remain silent in some lymphocytes [a type of immune system cell] and what are the triggers for the replication of the virus. The virus can be completely asleep in some cells.
We are interested in mechanisms of entry of the virus into cells-- how chemokines--small protein molecules that guide cells--block the entry of the virus.

[Remember: The goal is to flush out and kill the latent HIV virus in "viral reservoirs" that remain in the body even when viral load is considered undetectable.]

One thing we do is test new compounds. We receive compounds from pharmaceutical companies, universities, and small biotech companies, and we check the antiviral activity of these compounds--those that can induce activation of the virus, and some that block the entry of HIV into the cell.

To do this, we check the compounds in recombinant viruses and some cell models [HIV grown in labs rather than from people’s bodies]--they are cheap and sensitive and we can check the induction and replication.

We are studying the mechanisms by which the virus activates.

Right now we are looking a compound, jatrophane diterpene (SJ23B), that triggers SJ23 ( a cell membrane protein). It's a plant extract from a plant called Euphorbia that is found in the Mediterranean. This chemical compound is very useful to reactivate the virus. [The abstract states that SJ23B is 10 times better at activating latent virus than prostratin, another HIV activating compound.]

It's exciting--the compound works using two different mechanisms. When cells are latent, it reactivates the virus. Also, it protects  uninfected cells around any infected cells.
So it activates HIV but decreases HIV infection in culture [in the Petri dish or test tube]. The idea would be to use pulsing treatments—on again, off again.

Next step: To test the compound in mice.
Obstacles: There is not much money for basic science research in Europe.

*  Basic research is essentially test-tube and petri dish research. The work, if it is successful, is eventually tested in people. That is called clinical research.
For hardcore science buffs--here is the actual abstract that was presented at the conference:

SJ23B, a jatrophane diterpene, induces HIV Receptors down-regulation and HIV transcription through activation of PKCs and Ras-MEK pathway

L.M. Bedoya1, N. Marquez2, N. Martinez3, S. Gutiérrez-Eisman3, A. Alvarez1, M.A. Calzado2, J.M. Rojas3, G.
Appendino4, E. Muñoz2, J. Alcami1

1Centro Nacional de Microbiología, Instituto de Salud Carlos III, AIDS Immunopathology Department,
Majadahonda, Spain, 2Facultad de Medicina, Universidad de Córdoba, Departamento de Biología Celular,
Fisiología e Inmunología, Cordoba, Spain, 3Centro Nacional de Microbiología, Instituto de Salud Carlos III,
Cellular Biology Department, Majadahonda, Spain, 4Università del Piemonte Orientale, Dipartimento di
Scienze Chimiche, Alimentari, Farmaceutiche e Farmacologiche, Novara, Italy

Background: Viral reservoirs should be target of antiretroviral therapy to eliminate HIV infection. Although
antiretroviral therapy (ART) is able to control the infection, side effects, toxicities and emergence of viral
resistances can limit their utility. Thus, discovery of new antiretroviral drugs is strongly needed. We describe
here the effect of SJ23B on HIV reactivation and viral receptor expression.

Methods: Antiviral assays were performed with recombinant or wild type HIV. Culture pre-treatment with
chemical inhibitors were performed to evaluate SJ23B implications in biochemical pathways. Transcriptional
activity was evaluated in resting PBMCs transfected with luciferase plasmids under the control of the HIV-1-LTR
or consensus sequences for Sp1 or NF-kB. Ras, ERK, JNK and cRel/NF-kB family of transcription factors
expression were analyzed by western blotting and/or gel-shift-assay. Apoptosis induction were evaluated in
preactivated or resting PBMCs by annexin expression and long-term cell viability.

Results: SJ23B induced internalization of HIV-1 receptors CD4, CXCR4 and CCR5 preventing R5 and X4 viral
infection in human primary T cells at the nanomolar range. Moreover, SJ23B was a potent antagonist of HIV-1
latency in resting PBMCs, being at least 10-fold more potent than prostratin. Studies with isoform-specific PKC,
MEK and JNK inhibitors suggest a clear involvement of classical and novel PKCs (cPKCs and nPKCs) in receptor
down-regulation and cPKCs, nPKCs and Ras-MEK-ERK pathway in transcriptional reactivation. We further
demonstrated that SJ23B induces phosphorylation of ERK, JNK and IκBα as well degradation of IκBα leading to
NF-kB and Sp1 sites interaction in primary cells. Moreover, SJ23B showed no toxicity even in long-term

IAS Workshop – HIV Reservoirs and Strategies to Control Them –Abstracts – Oral Presentation - 17 July 2010, Vienna, Austria

Conclusions: SJ23B is a potent anti-HIV agent, sharing some mechanisms of action with prostratin, but
structurally different from phorbol-esters. This compound induces two responses, HIV reactivation through
transactivation of HIV-LTR and down-regulation of HIV receptors, then inducing reservoir activation and
prevention of de novo infection of susceptible CD4+ cells.

Presenting author email:

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