The Effect of Inositol Hexakisphosphate on HIV-1 Particle Production and Infectivity can be Modulated by Mutations that Affect the Stability of the Immature Gag Lattice

The assembly of an HIV-1 particle begins with the construction of a spherical lattice composed of hexamer subunits of the Gag polyprotein. The cellular metabolite inositol hexakisphosphate (IP6) binds and stabilizes the immature Gag lattice via an interaction with the six-helix bundle (6HB), a crucial structural feature of Gag hexamers that modulates both virus assembly and infectivity. The 6HB must be stable enough to promote immature Gag lattice formation, but also flexible enough to be accessible to the viral protease, which cleaves the 6HB during particle maturation. 6HB cleavage liberates the capsid (CA) domain of Gag from the adjacent spacer peptide 1 (SP1) and IP6 from its binding site. This pool of IP6 molecules then promotes the assembly of CA into the mature conical capsid that is required for infection. Depletion of IP6 in virus-producer cells results in severe defects in assembly and infectivity of wild-type (WT) virions. Here we show that in an SP1 double mutant (M4L/T8I) with a hyperstable 6HB, IP6 can block virion infectivity by preventing CA-SP1 processing. Thus, depletion of IP6 in virus-producer cells markedly increases M4L/T8I CA-SP1 processing and infectivity. We also show that the introduction of the M4L/T8I mutations partially rescues the assembly and infectivity defects induced by IP6 depletion on WT virions, likely by increasing the affinity of the immature lattice for limiting IP6. These findings reinforce the importance of the 6HB in virus assembly, maturation, and infection and highlight the ability of IP6 to modulate 6HB stability.

Anemia Burden, Types and Associated Risk Factors among Kenyan Human Immunodeficiency Virus-1 and Mycobacterium Tuberculosis Co-infected Injection Substance Users

BACKGROUND

Although injection substance users and individuals co-infected with Human Immunodeficiency Virus-1 and Mycobacterium tuberculosis suffer marked hematologic derangements, the rates, levels, morphologic types and associated risk factors of anemia among Human immunodeficiency virus and Mycobacterium tuberculosis coinfected injection substance users has not been reported in Kenya.

METHODS

This cross-sectional study determined anemia rates, levels and morphologic types. Anemia was associated with clinical markers of disease- underweight, immunosuppression and viral load. Complete blood count, CD4 T-cell enumeration and viral load were determined via standard laboratory methods.

RESULTS

All injection substance users had higher rates of anaemia (HIV+TB+ ISUs, 79.3%; HIV-TB+ISUs, 70.0%; HIV+TB- ISUs, 56.6% and HIV-TB- ISUs, 56.2%) relative to non-ISUs (16.6%; P<0.05). A significant proportion of HIV+TB+ISUs (47.8%) developed severe anemia than other clinical groups. The commonest morphologic type of anemia in HIV+TB+ISUs was microcytic hypochromic (43.5%) followed by normocytic hypochromic (17.4%) relative to the other clinical groups. HIV+TB+ ISUs with CD4 T-cells <200/uL (OR: 2.94, 95% CI: 1.41-6.13, P=0.004) and CD4 Tcells of 200-349/uL (OR: 3.24, 95% CI: 1.66-6.31, P=0.001) associated with higher odds of developing anemia.

CONCLUSION

This study revealed that severe anemia and microcytic hypochromic anemia are the most common erythrocytic sequelae among Human Immunodeficiency Virus-1 and Mycobacterium tuberculosis co-infected ISUs. Those with CD4 T-cells < 350/uL are utmost expected to develop anemia.

The inhibition process of HIV-1 integrase by diketoacids molecules: Understanding the factors governing the better efficiency of dolutegravir

The Human Immunodeficiency Virus-1 integrase is responsible for the covalent insertion of a newly synthesized double-stranded viral DNA into the host cells, and is an emerging target for antivirus drug design. Raltegravir (RAL) and elvitegravir (EVG) are the first two integrase strand transfer inhibitors used in therapy. However, treated patients eventually develop detrimental resistance mutations. By contrast, a recently approved drug, dolutegravir (DTG), presents a high barrier to resistance. This study aims to understand the increased efficiency of DTG upon focusing on its interaction properties with viral DNA. The results showed DTG to be involved in more extended interactions with viral DNA than EVG. Such interactions involve the halobenzene and scaffold of DTG and EVG and bases 5'G^-43', 3'A³5'and 3'C⁴5'.