Current HIV Research - Volume 17, Issue 6, 2019

The Human Immunodeficiency Virus (HIV-1) infection remains a persistent predicament for the State of Texas, ranking seventh among the most documented HIV cases in the United States. In this regard, the Rio Grande Valley (RGV) in South Texas is considered as one of the least investigated areas of the state with respect to HIV infection and HIV associated comorbidities. Considering the 115% increase in average HIV incidence rates per 100,000 within the RGV from 2007-2015, it is worth characterizing this population with respect to their HIV-1 infection, HIV-1 Associated Neurocognitive Disorders (HAND), and the association of treatment with combined antiretroviral therapy (cART). Moreover, the increased rate of Type-2 Diabetes (T2D) in the RGV population is intertwined with that of HIV-1 infection facing challenges due to the lack of knowledge about prevention to inadequate access to healthcare. Hence, the role of T2D in the development of HAND among the people living with HIV (PLWH) in the RGV will be reviewed to establish a closer link between T2D and HAND in cART-treated patients of the RGV.

HIV infection causes CD4 depletion and immune deficiency. The virus infects CD4 T cells through binding to CD4 and one of the chemokine coreceptors, CXCR4 (X4) or CCR5 (R5). It has also been known that HIV tropism switch, from R5 to X4, is associated with rapid CD4 depletion, suggesting a key role of viral factors in driving CD4 depletion. However, the virological driver for HIV-mediated CD4 depletion has not been fully elucidated. We hypothesized that HIV-mediated chemokine coreceptor signaling, particularly chronic signaling through CXCR4, plays a major role in CD4 dysfunction and depletion; we also hypothesized that there is an R5X4 signaling (R5X4sig) viral subspecies, evolving from the natural replication course of R5-utilizing viruses, that is responsible for CD4 T cell depletion in R5 virus infection. To gain traction for our hypothesis, in this review, we discuss a recent finding from Cui and co-authors who described the rapid tropism switch and high pathogenicity of an HIV-1 R5 virus, CRF01_AE. We speculate that CRF01_AE may be the hypothetical R5X4sig viral species that is rapidly evolving towards the X4 phenotype. We also attempt to discuss the intricate relationships between HIV-mediated chemokine coreceptor signaling, viral tropism switch and HIV-mediated CD4 depletion, in hopes of providing a deeper understanding of HIV pathogenesis in blood CD4 T cells.

Background: The advent of resistance-associated mutations in HIV-1 is a barrier to the success of the ARTs. Objective: In this study, the abundance of HIV-1 infection in Iranian children, and also detection of the TDR in naïve HIV-1 infected pediatric (under 12 years old) were evaluated. Materials: From June 2014 to January 2019, a total of 544 consecutive treatment-naïve HIV-1- infected individuals enrolled in this study. After RNA extraction, amplification, and sequencing of the HIV-1 pol gene, the DRM and phylogenetic analysis were successfully performed on the plasma specimens of the ART-naïve HIV-1-infected-children under 12 years old. The DRMs were recognized using the Stanford HIV Drug Resistance Database. Results: Out of the 544 evaluated treatment-naïve HIV-1-infected individuals, 15 (2.8%) cases were children under 12 years old. The phylogenetic analyses of the amplified region of pol gene indicated that all of the 15 HIV-1-infected pediatric patients were infected by CRF35_AD, and a total of 13.3% (2/15) of these children were infected with HIV-1 variants with SDRMs (one child harbored two related SDRMs [D67N, V179F], and another child had three related SDRMs [M184V, T215F, and K103N]), according to the last algorithm of the WHO. No PIs-related SDRMs were observed in HIV-1-infected children. Conclusion: The current study demonstrated that a total of 13.3% of treatment-naïve HIV-1-infected Iranian pediatrics (under 12 years old) were infected with HIV-1 variants with SDRMs. Therefore, it seems that screening to recognize resistance-associated mutations before the initiation of ARTs among Iranian children is essential for favorable medication efficacy and dependable prognosis.

Background: An effective vaccine against human immunodeficiency virus 1 (HIV-1) is an important global health priority. Despite many efforts in the development of the HIV-1 vaccine, no effective vaccine has been approved yet. Recently, polyepitope vaccines including several immunogenic and conserved epitopes of HIV-1 proteins have received special attention. Methods: In this study, HIV-1 Nef, Tat, Gp160 and P24 proteins were considered for selection of immunodominant and conserved epitopes due to their critical roles in the viral life cycle and pathogenesis. At first, the Nef60-84-Nef126-144-Tat29-49-Gp16030-53-Gp160308-323-P248-151 DNA construct was designed using in silico studies. Then, the DNA construct was subcloned in pEGFP-N1 and pET- 24a (+) expression vectors and the rNef-Tat-Gp160-P24 polyepitope peptide was generated in E.coli expression system for in vitro delivery using novel cell-penetrating peptides (CPPs), LDP-NLS and CyLoP-1, in a non-covalent manner. Also, the HR9 and MPG CPPs were used to transfer the DNA construct. Results: Our results showed that the recombinant polyepitope peptide generated in Rosetta strain migrated as a clear band of ~31 kDa in SDS-PAGE. The SEM data confirmed the formation of stable nanoparticles with a size below 250 nm. MTT assay revealed that the complexes did not represent any considerable cytotoxic effect compared to untreated cells. The results of fluorescence microscopy, flow cytometry and western blotting indicated that these CPPs successfully delivered polyepitope constructs into HEK-293T cell line. Conclusion: These data suggested that these CPPs can be used as a promising approach for the development of the HIV-1 vaccine.

Background: HIV-1 protease inhibitor (PI) is one of the most potent classes of drugs in combinational antiretroviral therapies (cART). When a PI is used in combination with other anti- HIV drugs, cART can often suppress HIV-1 below detection thus prolonging the patient’s lives. However, the challenge often faced by patients is the emergence of HIV-1 drug resistance. Thus, PIs with high genetic-barrier to drug-resistance are needed. Objective: The objective of this study was to develop a novel and simple fission yeast (Schizosaccharomyces pombe) cell-based system that is suitable for high throughput screening (HTS) of small molecules against HIV-1 protease (PR). Methods: A fission yeast RE294-GFP strain that stably expresses HIV-1 PR and green fluorescence protein (GFP) under the control of an inducible nmt1 promoter was used. Production of HIV-1 PR induces cellular growth arrest, which was used as the primary endpoint for the search of PIs and was quantified by an absorbance-based method. Levels of GFP production were used as a counter-screen control to eliminate potential transcriptional nmt1 inhibitors. Results: Both the absorbance-based HIV-1 PR assay and the GFP-based fluorescence assay were miniaturized and optimized for HTS. A pilot study was performed using a small drug library mixed with known PI drugs and nmt1 inhibitors. With empirically adjusted and clearly defined double-selection criteria, we were able to correctly identify the PIs and to exclude all hidden nmt1 inhibitors. Conclusion: We have successfully developed and validated a fission yeast cell-based HTS platform for the future screening and testing of HIV-1 PR inhibitors.

Background: Pretreatment drug resistance (PDR) poses an increasing threat to the success of antiretroviral treatment (ART) programs in China. We aimed to conduct a survey of PDR among HIV patients in an area in Southwest China with extensive drug trafficking. Methods: Consecutive cross-sectional surveys were conducted in Liangshan Prefecture of Sichuan Province from 2009 to 2018 based on the WHO-recommended method. PDR was identified by testing pol region sequences with the Stanford HIVdb algorithm (version 7.0). PDR prevalence and related factors were assessed by multivariable logistic regression. The transmission of HIV drug resistance was analyzed using a genetic transmission network. Results: HIV-1 pol genes from 1889 patients were successfully amplified. The distribution of HIV- 1 genotypes was as follows: CRF07_BC (94.0%), CRF08_BC (2.3%), CRF01_AE (2.0%) and others (1.4%). Of the participants, 6.9% (95% CI: 4.1-8.1%) had pretreatment resistance to 12 antiretroviral drugs recommended by the WHO, and nucleoside reverse transcriptase inhibitor (NRTI), non-nucleoside reverse transcriptase inhibitor (NNRTI) and protease inhibitors (PI) resistance were identified among 1.4% (95% CI: 0.7-3.4%), 5.8% (95% CI: 1.2-8.7%) and 0.4% (95% CI: 0.1- 3.0%) of the patients, respectively. In the multivariate logistic model, the prevalence of PDR was 1.52-fold higher among intravenous drug users (IDUs) than among patients infected by heterosexual transmission (95% CI: 1.07-2.38; P=0.049), and the prevalence of PDR among patients diagnosed from 2017-2018 was 2.03-fold higher than that among patients diagnosed from 2009-2016 (95% CI: 1.18-5.76; P=0.018). A total of 26 clusters containing PDR and a rapidly growing drug resistancerelated cluster containing the E138Q and V179D mutations were identified by genetic transmission network analysis. Conclusion: The results show a moderate overall level of PDR prevalence and rapidly growing drug resistance over time. Preventive intervention should be focused on controlling the HIV epidemic among drug users, and surveillance is urgently needed to monitor the trend of PDR.