Nat Commun: Exosomes deliver mRNA to achieve stable suppression of HIV

AIDS (AIDS), the full name is Acquired Immune Deficiency Syndrome, which is a very harmful infectious disease caused by the human immunodeficiency virus (HIV)
.

The HIV virus can attack and severely damage the human immune system.

According to UNAIDS data, the number of HIV carriers and AIDS patients worldwide has increased from 34.
3 million at the end of 2013 to 38 million at the end of 2018, and the number is still growing rapidly
.

Although the continuous progress of antiretroviral therapy (ART) has greatly extended the lifespan and prognosis of AIDS patients, it will also bring serious side effects and the emergence of drug resistance
.

The targeted DNA methylation of 5'LTR provides a promising approach for HIV suppression strategies
.

Especially in order to enrich DNA methylation, DNA methyltransferase is fused with zinc finger protein ZFP-362b

On September 20, 2021, the research team of the Gene Therapy Center of the Beckman Institute published a research paper entitled: Exosome-mediated stable epigenetic repression of HIV-1 in Nature Communications
.

The research developed a zinc finger protein (ZFP-362) targeting the HIV-1 promoter, which is fused with the active domain of DNA methyltransferase 3A to induce long-term stable HIV-1 epigenetics Restrain
.

The delivery of mRNA of this inhibitory protein through exosomes can inhibit the level of HIV in the bone marrow, spleen and brain of mice in vivo and prevent its replication

This research paves the way for an exosome-mediated therapeutic drug system delivery platform to epigenetically inhibit HIV-1 infection
.

In order to achieve stable transcriptional inhibition of HIV-1, the research team developed a vector expressing the recombinant fusion protein ZFP 362b-DNMT3A (ZD3A), which can be localized to the nucleus with the help of an embedded nuclear localization signal (NLS)
.

The ZFP can bind to the NF-kB duplex binding site in the LTR promoter of HIV-1 and fused with the DNA methyltransferase 3 domain (3A) to produce (ZD3A)

Next, the research team constructed several ZFP362 fusion constructs with various repressor domains: ZPAMt fused with the active domains of PWWP, ADD and methyltransferase, and fused with KRAB and methyltransferase domains.
ZPAMt
.

ZPAMt and ZPAMt effectively inhibit virus expression

In order to determine the mechanism of action involved in the observed silencing, the research team used ZPAMt and ZKMt transfected cells to perform immunoprecipitation and confirmed the binding of ZFP-362 to the HIV-1 promoter
.

In the transfected CHI-Ju cells, the research team observed effective inhibition of Gag RNA, and detected the targeted enrichment of CpG methylation in the LTR region of HIV-1 relative to the control by methyl DNA immunoprecipitation assay

Finally, in order to determine the antiviral efficacy of ZPAMt, the research team implanted HIV-1 infected peripheral blood mononuclear cells (PBMC) into humanized immunodeficient mice, and then administered cART treatment and ZPAMt injections for two weeks
.

The results showed that ZPAMt significantly and stably inhibited HIV-1 expression, the mechanism is the significant methylation of 5'LTR

In summary, this work proves that the delivery of recombinant ZPAMt via exosomes can target HIV-1, silence it epigenetically, and induce a suppressive phenotype in virus-infected cells
.

This delivery system paves the way for future development of HIV-inhibiting therapies

Original source:

Original source:

Shrivastava, S.
, Ray, RM, Holguin, L.
et al.
Exosome-mediated stable epigenetic repression of HIV-1 .
Nat Commun 12, 5541 (2021).
https://doi.
org/10.
1038/s41467-021- 25839-2.

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