Mucosal stromal fibroblasts markedly enhance HIV infection of CD4+ T cells

© 2017 Neidleman et al.Understanding early events of HIV transmission within mucosal tissues is vital for developing effective prevention strategies. Here, we report that primary stromal fibroblasts isolated from endometrium, cervix, foreskin, male urethr

Mucosal stromal fibroblasts markedly enhance HIV infection of CD4+ T cells

© 2017 Neidleman et al.Understanding early events of HIV transmission within mucosal tissues is vital for developing effective prevention strategies. Here, we report that primary stromal fibroblasts isolated from endometrium, cervix, foreskin, male urethr

Naturally Occurring Fragments from Two Distinct Regions of the Prostatic Acid Phosphatase Form Amyloidogenic Enhancers of HIV Infection

Semen is the major vector for HIV-1 transmission. We previously isolated C-proximal fragments of the prostatic acid phosphatase (PAP) from semen which formed amyloid fibrils that potently enhanced HIV infection. Here, we used the same methodology and identified another amyloidogenic peptide. Surprisingly, this peptide is derived from an N-proximal fragment of PAP (PAP85-120) and forms, similar to the C-proximal fragments, positively charged fibrillar structures that increase virion attachment to cells. Our results provide a first example for amyloid formation by fragments of distinct regions of the same precursor and further emphasize the possible importance of amyloidogenic peptides in HIV transmission

Guanylate Binding Protein (GBP) 5 Is an Interferon-Inducible Inhibitor of HIV-1 Infectivity.

Guanylate binding proteins (GBPs) are an interferon (IFN)-inducible subfamily of guanosine triphosphatases (GTPases) with well-established activity against intracellular bacteria and parasites. Here we show that GBP5 potently restricts HIV-1 and other retroviruses. GBP5 is expressed in the primary target cells of HIV-1, where it impairs viral infectivity by interfering with the processing and virion incorporation of the viral envelope glycoprotein (Env). GBP5 levels in macrophages determine and inversely correlate with infectious HIV-1 yield over several orders of magnitude, which may explain the high donor variability in macrophage susceptibility to HIV. Antiviral activity requires Golgi localization of GBP5, but not its GTPase activity. Start codon mutations in the accessory vpu gene from macrophage-tropic HIV-1 strains conferred partial resistance to GBP5 inhibition by increasing Env expression. Our results identify GBP5 as an antiviral effector of the IFN response and may explain the increased frequency of defective vpu genes in primary HIV-1 strains

Mucosal stromal fibroblasts markedly enhance HIV infection of CD4+ T cells

<div><p>Understanding early events of HIV transmission within mucosal tissues is vital for developing effective prevention strategies. Here, we report that primary stromal fibroblasts isolated from endometrium, cervix, foreskin, male urethra, and intestines significantly increase HIV infection of CD4+ T cells–by up to 37-fold for R5-tropic HIV and 100-fold for X4-tropic HIV–without themselves becoming infected. Fibroblasts were more efficient than dendritic cells at <i>trans</i>-infection and mediate this response in the absence of the DC-SIGN and Siglec-1 receptors. In comparison, mucosal epithelial cells secrete antivirals and inhibit HIV infection. These data suggest that breaches in the epithelium allow external or luminal HIV to escape an antiviral environment to access the infection-favorable environment of the stromal fibroblasts, and suggest that resident fibroblasts have a central, but previously unrecognized, role in HIV acquisition at mucosal sites. Inhibiting fibroblast-mediated enhancement of HIV infection should be considered as a novel prevention strategy.</p></div