Near Real-Time Identification of Recent Human Immunodeficiency Virus Transmissions, Transmitted Drug Resistance Mutations, and Transmission Networks by Multiplexed Primer ID-Next-Generation Sequencing in North Carolina.

BACKGROUND: The identification of recent human immunodeficiency virus (HIV) 1 infections among people with new HIV diagnoses is important to both tailoring and assessing the impact of HIV-1 prevention strategies. METHODS: We developed a multiplexed Primer ID-next-generation sequencing approach to identify recent infections by measuring the intrahost viral diversity over multiple regions of the HIV-1 genome, in addition to detecting drug resistance mutations (DRMs) and phylogenetically linked clusters. We summarize the field implementation of this all-in-one platform among persons with newly diagnosed HIV-1 by the North Carolina State Laboratory of Public Health in 2018. RESULTS: Overall, recent infection was identified in 94 (35%) of 268 patients with new HIV diagnoses. People <30 years old, and people who inject drugs were more likely to have diagnoses of recent infection. The reverse-transcriptase region K103N was the most commonly detected DRM (prevalence, approximately 15%). We found a total of 28 clusters, and persons with recent infection were more likely to be cluster members than were those with chronic infections (P = .03). CONCLUSIONS: We demonstrate the rapid identification of recent infection and pretreatment DRMs coupled with cluster analysis that will allow prioritization of linkage to care, treatment, and prevention interventions to those at highest risk of onward transmission.

Glucose regulation of integrin-associated protein cleavage controls the response of vascular smooth muscle cells to insulin-like growth factor-I.

Vascular smooth muscle cells (SMC) maintained in high glucose are more responsive to IGF-I than SMC maintained in normal glucose due to a difference in the Shc phosphorylation response. In this study we aimed to determine the mechanism by which glucose regulates the sensitivity of SMC to IGF-I. For Shc to be phosphorylated in response to IGF-I it must be recruited to tyrosine-phosphorylated sites on Src homology 2 domain-containing phosphatase (SHP) substrate-1 (SHPS-1). The association of integrin-associated protein (IAP) with SHPS-1 is required for SHPS-1 tyrosine phosphorylation. When SMC were grown in 5 mm glucose, the amount of intact IAP was reduced, compared with SMC grown in 25 mm glucose. This reduction was due to proteolytic cleavage of IAP. Proteolysis of IAP resulted in loss of its SHPS-1 binding site, which led to loss of SHPS-1 phosphorylation. Analysis of the conditioned medium showed that there was more protease activity in the medium from SMC cultured in 5 mm glucose as compared with 25 mm. Inhibition of matrix metalloprotease-2 synthesis using RNA interference or its activity using a specific protease inhibitor protected IAP from cleavage. This protection was associated with an increase in IAP-SHPS-1 association, increased recruitment and phosphorylation of Shc, and increased cell growth in response to IGF-I. Our results show that the enhanced response of SMC in 25 mm glucose to IGF-I is due to the protection of IAP from proteolytic degradation, thereby increasing its association with SHPS-1 and allowing the formation of the SHPS-1-Shc signaling complex.

Modulation of integrin antagonist signaling by ligand binding of the heparin-binding domain of vitronectin to the alphaVbeta3 integrin.

The interaction between the arginine glycine and aspartic acid motif (RGD) of integrin ligands such as vitronectin and the integrin receptor alphaVbeta3 in mediating cell attachment has been well described. Similarly, the ability of disintegrins, small RGD containing peptides, to inhibit cell attachment and other cellular processes has also been studied extensively. Recently, we characterized a second site of interaction between vitronectin and its integrin partner. We determined that amino acids within the heparin-binding domain of vitronectin bind to a cysteine loop (C-loop) region of beta3 and that this interaction is required for the positive effects of alphaVbeta3 ligand occupancy on IGF-I signaling in smooth muscle cells. In this study we examine the signaling events activated following ligand binding of disintegrins to the alphaVbeta3 and the ability of these signals to be regulated by binding of the heparin-binding domain of vitronectin. We demonstrate that disintegrin ligand binding activates a series of events including the sequential activation of the tyrosine kinases c-Src and Syk. This leads to the activation of calpain and the cleavage of the beta3 cytoplasmic tail. Addition of vitronectin or a peptide homologous to the heparin-binding domain inhibited activation of this pathway. Our results suggest that the signaling events that occur following ligand binding to the alphaVbeta3 integrin reflects a balance between the effects mediated through the RGD binding site interaction and the effects mediated by the heparin binding site interaction and that for intact vitronectin the effect of the heparin-binding domain predominates.

A monoclonal antibody against alphaVbeta3 integrin inhibits development of atherosclerotic lesions in diabetic pigs.

Atherosclerotic lesions develop and progress more rapidly in diabetic patients than in nondiabetic individuals. This may be caused by accelerated lesion formation in the high-glucose environment of diabetes. Smooth muscle cells (SMCs) cultured in high glucose are more responsive to growth factors such as insulin-like growth factor-1 (IGF-1). This enhanced response to IGF-1 is due in part to increased activation of the alpha(V)beta(3) integrin. We tested whether alpha(V)beta(3) integrin activation was increased in diabetic animals and whether an antibody to beta(3) would inhibit IGF-1 action and development of atherosclerosis. Eight male pigs were made diabetic with streptozotocin and fed a high-fat diet. A F(ab)(2) antibody fragment directed at beta(3) was infused into one femoral artery, whereas the other artery received control F(ab)(2) for 3.5 months. There was a 65 +/- 8% reduction in atherosclerotic lesion area in the arteries treated with F(ab)(2) antibody to beta(3). Phosphorylation of beta(3) was reduced by 75 +/- 18% in vessels treated with the antibody. Shc and mitogen-activated protein kinase phosphorylation, which are required for IGF-1-stimulated SMC proliferation, were also significantly reduced. We conclude that activation of IGF-1 receptor and alpha(V)beta(3)-linked signaling pathways accelerates atherosclerosis in diabetes and that administration of an antibody to beta(3) to diabetic pigs inhibits alpha(V)beta(3) activation, IGF-1-stimulated signaling, and atherosclerotic lesion development. This approach offers a potential therapeutic approach to the treatment of this disorder.

Identification of compounds that inhibit IGF-I signaling in hyperglycemia.

Increased responsiveness of vascular cells to the growth factor IGF-I has been implicated in complications associated with diabetes. Here we describe the development of an assay and screening of a library of compounds for their ability to accelerate cleavage of the transmembrane protein integrin-associated protein (IAP) thereby disrupting the association between IAP and SHPS-1 which we have shown as critical for the enhanced response of vascular cells to IGF-I. The cell-based ELISA utilizes an antibody that specifically detects cleaved, but not intact, IAP. Of the 1040 compounds tested, 14 were considered active by virtue of their ability to stimulate an increase in antibody-binding indicative of IAP cleavage. In experiments with smooth muscle and retinal endothelial cell cultures in hyperglycemic conditions, each active compound was shown to accelerate the cleavage of IAP, and this was associated with a decrease in IAP association with SHPS-1 as determined by coimmunoprecipitation of the proteins from cell lysates. As a consequence of the acceleration in IAP cleavage, the compounds were shown to inhibit IGF-I-stimulated phosphorylation of key signaling molecules including Shc and ERK1/2, and this in turn was associated with a decrease in IGF-I-stimulated cell proliferation. Identification of these compounds that utilize this mechanism has the potential to yield novel therapeutic approaches for the prevention and treatment of vascular complications associated with diabetes.