HIV capsid inhibition

In this article we will explore the fascinating world of HIV capsid inhibition, a topic that has piqued the interest of many people over the years. HIV capsid inhibition has been the subject of numerous studies and research, and its relevance has remained over time. From its origins to its impact on today's society, HIV capsid inhibition has left a significant mark on different aspects of daily life. Through this article, we will delve into the different aspects that make HIV capsid inhibition such a relevant and interesting topic, examining its evolution over time and its influence in different areas. Get ready to immerse yourself in the exciting universe of HIV capsid inhibition!

In the management of HIV/AIDS, HIV capsid inhibitors are antiretroviral medicines that target the capsid shell of the virus. This is in contrast to other antiretroviral drugs used to treat HIV, which do not directly target the viral capsid.[1] These have also been termed "Capsid-targeting Antivirals", "Capsid Effectors", and "Capsid Assembly Modulators (CAMs)". Because of this, drugs that specifically inhibit the HIV capsid are being developed in order to reduce the replication of HIV, and treat infections that have become resistant to current antiretroviral therapies.[2]

HIV capsid

Structure of HIV capsid obtained from crystallography.

The mechanism of HIV infection involves the transport and integration of the viral genome into the DNA of the host cell. This process involves both viral and cellular proteins which reverse transcribe the viral RNA to double-stranded DNA, and incorporate the viral DNA into the host cell genome.[3]

The capsid surrounding the viral RNA, nucleocapsids, reverse transcriptase, and integrase plays a key role in the infection process. The capsid is composed of amino- and carboxy-terminal domains that form hexameric and pentameric rings. These rings assemble to form a cone-shaped structure surrounding the viral RNA and proteins.[4] Upon entering the cytoplasm of a host cell, the capsid goes through an unfolding process that releases the viral RNA and proteins into the cell.[citation needed]

The uncoating process is a highly ordered multistep process in which the capsid is weakened and most or all capsid proteins are removed from the shell. Upsetting this process can have downstream effects that significantly reduce the infectivity of the virus. Because of this, capsid uncoating is a favorable target for antiretroviral medicines.[5]

Therapeutic applications

Structure of Lenacapavir (GS-6207).

Lenacapavir

In 2022, the capsid inhibitor lenacapavir received approval from the European Medicines Agency, Health Canada, and the United States Food and Drug Administration as a first-in-class medication to treat HIV-1 infection.[6][7][8][9][10]

Lenacapavir functions by binding to the hydrophobic pocket formed by two neighboring protein subunits in the capsid shell.[11] This bond stabilizes the capsid structure and inhibits the functional disassembly of the capsid in infected cells.[11]

Structure of GS-CA1.

In the years prior to the development of capsid inhibitors, HIV patients were generally treated with a combination of reverse transcriptase inhibitors, protease inhibitors, integrase inhibitors, and entry inhibitors.[12] Lenacapavir is approved for those who develop resistance to such regimens, for use in addition to other HIV treatments.[10]

Research

History

In 2003, the first compound to bind the HIV-1 capsid was reported and termed "CAP-1".[13][14] Since then, over 40 molecules have been reported to inhibit HIV-1 by binding capsid, with five distinct chemotypes described.[2] The binding pocket for Lenacapavir was first described in 2009, with the small molecule PF-3450074 (PF74) developed by Pfizer.[15] PF74 was not developed clinically due to its fast metabolic breakdown and poor bioavailability, but its binding pocket has been well characterized and frequently targeted.[2]

GS-CA1

GS-CA1 is an experimental small-molecule capsid inhibitor developed by Gilead Sciences. GS-CA1 and GS-6207 are analogues, with both molecules showing promising anti-HIV activity.[11]

GS-CA1 functions by binding directly to the HIV capsid. This bonding disrupts the uncoating process which inhibits both the release of viral RNA and proteins into the cytoplasm, and also inhibits the production of new capsid shells within the cell.[16]

Structure of ebselen.

Ebselen

Ebselen was identified as a capsid inhibitor using a fluorescence assay on a library of pharmacological compounds. Ebselen covalently bonds to the C-terminal domain of the HIV-1 capsid, which inhibits the uncoating process. Ebselen shows anti-HIV activity in infected cell lines.[12]

Peptides

Phage display was used to identify peptides that bind the HIV-1 capsid protein, and the most promising peptide inhibitor was the Capsid Assembly Inhibitor (CAI) peptide.[17] CAI prevented the formation of mature capsids, but its poor permeability in cells limited its use.[17] Other peptide inhibitors have been reported,[18] as well as next generation inhibitors with increased stability, permeability, and antiviral activity.[19] These peptides interact at the C-terminal domain of the HIV-1 capsid, similar to Ebselen.[2]

Uracil-based drugs

Uracil based scaffolds such as bispyrimidine dione and tetrapyrimidine dione derivatives have shown activity as HIV-1 p24 capsid inhibitors in an in vitro setting but need further exploration.[20]

References

  1. ^ "FDA-Approved HIV Medicines". HIVinfo. Retrieved 2023-05-25.
  2. ^ a b c d McFadden WM, Snyder AA, Kirby KA, Tedbury PR, Raj M, Wang Z, Sarafianos SG (December 2021). "Rotten to the core: antivirals targeting the HIV-1 capsid core". Retrovirology. 18 (1): 41. doi:10.1186/s12977-021-00583-z. PMC 8693499. PMID 34937567.
  3. ^ Isel C, Ehresmann C, Marquet R (January 2010). "Initiation of HIV Reverse Transcription". Viruses. 2 (1): 213–243. doi:10.3390/v2010213. PMC 3185550. PMID 21994608.
  4. ^ Pornillos O, Ganser-Pornillos BK, Yeager M (January 2011). "Atomic-level modelling of the HIV capsid". Nature. 469 (7330): 424–427. Bibcode:2011Natur.469..424P. doi:10.1038/nature09640. PMC 3075868. PMID 21248851.
  5. ^ Ambrose Z, Aiken C (April 2014). "HIV-1 uncoating: connection to nuclear entry and regulation by host proteins". Virology. 454–455: 371–379. doi:10.1016/j.virol.2014.02.004. PMC 3988234. PMID 24559861.
  6. ^ Hitchcock, Allison M.; Kufel, Wesley D.; Dwyer, Keri A. Mastro; Sidman, Eric F. (January 2024). "Lenacapavir: A novel injectable HIV-1 capsid inhibitor". International Journal of Antimicrobial Agents. 63 (1): 107009. doi:10.1016/j.ijantimicag.2023.107009.
  7. ^ "Sunlenca EPAR". European Medicines Agency (EMA). 22 June 2022. Archived from the original on 26 August 2022. Retrieved 25 August 2022.
  8. ^ "Sunlenca Product information (oral)". Health Canada. 25 April 2012. Retrieved 23 December 2022.
  9. ^ "Sunlenca Product information (subcutaneous)". Health Canada. 25 April 2012. Retrieved 23 December 2022.
  10. ^ a b "FDA Approves New HIV Drug for Adults with Limited Treatment Options" (Press release). U.S. Food and Drug Administration (FDA). 22 December 2022. Archived from the original on 2 February 2024. Public Domain This article incorporates text from this source, which is in the public domain.
  11. ^ a b c Bester SM, Wei G, Zhao H, Adu-Ampratwum D, Iqbal N, Courouble VV, et al. (October 2020). "Structural and mechanistic bases for a potent HIV-1 capsid inhibitor". Science. 370 (6514): 360–364. Bibcode:2020Sci...370..360B. doi:10.1126/science.abb4808. PMC 7831379. PMID 33060363.
  12. ^ a b Thenin-Houssier S, de Vera IM, Pedro-Rosa L, Brady A, Richard A, Konnick B, et al. (April 2016). "Ebselen, a Small-Molecule Capsid Inhibitor of HIV-1 Replication". Antimicrobial Agents and Chemotherapy. 60 (4): 2195–2208. doi:10.1128/AAC.02574-15. PMC 4808204. PMID 26810656.
  13. ^ Tang C, Loeliger E, Kinde I, Kyere S, Mayo K, Barklis E, et al. (April 2003). "Antiviral inhibition of the HIV-1 capsid protein". Journal of Molecular Biology. 327 (5): 1013–1020. doi:10.1016/S0022-2836(03)00289-4. PMID 12662926.
  14. ^ Carnes, Stephanie K.; Sheehan, Jonathan H.; Aiken, Christopher (July 2018). "Inhibitors of the HIV-1 capsid, a target of opportunity". Current Opinion in HIV and AIDS. 13 (4): 359–365. doi:10.1097/COH.0000000000000472. PMC 6075716.
  15. ^ Blair WS, Pickford C, Irving SL, Brown DG, Anderson M, Bazin R, et al. (December 2010). Luban J (ed.). "HIV capsid is a tractable target for small molecule therapeutic intervention". PLOS Pathogens. 6 (12): e1001220. doi:10.1371/journal.ppat.1001220. PMC 3000358. PMID 21170360.
  16. ^ Yant SR, Mulato A, Hansen D, Tse WC, Niedziela-Majka A, Zhang JR, et al. (September 2019). "A highly potent long-acting small-molecule HIV-1 capsid inhibitor with efficacy in a humanized mouse model". Nature Medicine. 25 (9): 1377–1384. doi:10.1038/s41591-019-0560-x. PMC 7396128. PMID 31501601.
  17. ^ a b Sticht J, Humbert M, Findlow S, Bodem J, Müller B, Dietrich U, et al. (August 2005). "A peptide inhibitor of HIV-1 assembly in vitro". Nature Structural & Molecular Biology. 12 (8): 671–677. doi:10.1038/nsmb964. PMID 16041387. S2CID 5953442.
  18. ^ Bocanegra R, Nevot M, Doménech R, López I, Abián O, Rodríguez-Huete A, et al. (2011-09-08). "Rationally designed interfacial peptides are efficient in vitro inhibitors of HIV-1 capsid assembly with antiviral activity". PLOS ONE. 6 (9): e23877. Bibcode:2011PLoSO...623877B. doi:10.1371/journal.pone.0023877. PMC 3169566. PMID 21931621.
  19. ^ Zhang H, Zhao Q, Bhattacharya S, Waheed AA, Tong X, Hong A, et al. (May 2008). "A cell-penetrating helical peptide as a potential HIV-1 inhibitor". Journal of Molecular Biology. 378 (3): 565–580. doi:10.1016/j.jmb.2008.02.066. PMC 2695608. PMID 18374356.
  20. ^ Ramesh D, Mohanty AK, De A, Vijayakumar BG, Sethumadhavan A, Muthuvel SK, et al. (June 2022). "Uracil derivatives as HIV-1 capsid protein inhibitors: design, in silico, in vitro and cytotoxicity studies". RSC Advances. 12 (27): 17466–17480. Bibcode:2022RSCAd..1217466R. doi:10.1039/D2RA02450K. PMC 9190787. PMID 35765450.