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Mechanism of action of allosteric HIV-1 integrase inhibitors

Slaughter, Alison Paige
http://rave.ohiolink.edu/etdc/view?acc_num=osu1428684473

Abstract Details

2015, Doctor of Philosophy, Ohio State University, Pharmacy.
An essential step in the HIV-1 replication cycle is the integration of the viral DNA into the host chromatin, which is catalyzed by the viral enzyme integrase (IN). The cellular cofactor lens epithelial growth factor (LEDGF)/p75 plays a significant role in integration by acting as a bimodal tether between IN and chromatin. These interactions are crucial for HIV-1 replication and present attractive targets for antiviral therapy. Herein, I will present research aimed at dissecting the mechanism of action of novel allosteric HIV-1 IN inhibitors. Chapter 1 introduces HIV-1 IN biology, function and its inhibition. This chapter will focus on the structural biology and function of HIV-1 IN. The role of LEDGF/p75 in replication and integration site selection will be discussed. Finally, the chapter will discuss three mechanisms of IN inhibition: (I) FDA approved active site inhibitors; (2) IN multimerization as a therapeutic target; and (3) IN-LEDGF/p75 binding as a drug target. Chapter 2 presents the findings that novel allosteric HIV-1 IN inhibitors (ALLINIs) have a multimodal mechanism of action. We demonstrate that this class of compounds impairs both IN-LEDGF/p75 binding and LEDGF/p75-independent IN catalytic activities with similar IC50 values, defining them as bona fide allosteric inhibitors of IN function. Our findings argue strongly that improved ALLINI derivatives could exhibit desirable clinical properties. Chapters 3 and 4 dissect the structural and mechanistic basis for resistance to ALLINIs. The A128T IN and H171T IN substitution emerges under ALLINI-1 and BI-D selective pressure, respectively. Chapter 3 demonstrates that the A128T substitution does not affect inhibitor binding but alters the positioning of the inhibitor at the IN dimer interface. As a result, ALLINIs are no longer able to promote aberrant higher order IN oligomers. We conclude that ALLINIs primarily target IN multimerization rather than IN-LEDGF/p75 binding. Chapter 4 shows that the H171T substitution significantly reduces the affinity for BI-D binding to recombinant H171T IN CCD. X-ray crystal structures coupled with binding free energy calculations reveal the importance of the Nd- protonated imidazole group of His171 for high affinity BI-D binding. These findings reveal a distinct mechanism of resistance for the H171T IN mutation to ALLINI BI-D. Chapter 5 presents the design of small molecules that allowed us to probe the role of HIV-1 IN multimerization independently from IN-LEDGF/p75 interactions in infected cells. The most potent multimerization selective inhibitor potently blocks HIV-1 replication by inducing aberrant IN multimerization in virus particles. These findings delineate the significance of correctly ordered IN structure for HIV-1 particle morphogenesis and present a novel class of multimerization selective IN inhibitors as investigational probes for HIV-1 molecular biology. Finally, chapter 6 summarizes the findings and significance of this dissertation research as well as provides future perspectives. In summary, this dissertation has: (I) summarized the structure, function and inhibition of HIV-1 IN, (II) characterized the multimodal mechanism of ALLINIs, (III) studied the ALLINI resistant A128T IN substitution and (IV) H171T IN substitution and finally (V) characterized a multimerization selective IN inhibitor to understand the role of IN multimerization in HIV replication.
Mamuka Kvaratskhelia (Advisor)
James Fuchs (Committee Member)
Thomas Schmittgen (Committee Member)
Jesse Kwiek (Committee Member)
230 p.
Pharmacy Sciences; Virology
HIV Integrase; LEDGF; Allosteric inhibitors; Drug Resistance;

Recommended Citations

Citations

  • Slaughter, A. P. (2015). Mechanism of action of allosteric HIV-1 integrase inhibitors [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1428684473

    APA Style (7th edition)

  • Slaughter, Alison. Mechanism of action of allosteric HIV-1 integrase inhibitors. 2015. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1428684473.

    MLA Style (8th edition)

  • Slaughter, Alison. "Mechanism of action of allosteric HIV-1 integrase inhibitors." Doctoral dissertation, Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1428684473

    Chicago Manual of Style (17th edition)

osu1428684473
362
© 2015, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.