Lili Dai

Targeting HIV Prevention Based on Molecular Epidemiology Among Deeply Sampled Subnetworks of Men Who Have Sex With Men

BACKGROUND Molecular epidemiology can be useful in identifying clusters of human immunodeficiency virus (HIV) transmission that can be targeted for prevention. METHODS Regular screening of 2000 men who have sex with men (MSM) in Beijing, China, for HIV infection every 2 months identified 179 primary infections (2007-2010). HIV-1 pol sequences were obtained and used to infer the transmission network and identify transmitted drug resistance (TDR) among these individuals. We evaluated the use of clinical and network information to target prevention efforts. Prevention efficiency was calculated as the number of infections saved per number of interventions. RESULTS This cohort was infected with HIV-1 subtype B (28%), circulating recombinant form (CRF)_01 AE (53%), and CRF_07 BC (16%). The overall rate of TDR was low (5%), but the rate of clustering was high (64%), suggesting deep sampling of the subnetwork. Provision of a theoretically high-efficacy intervention like antiretroviral therapy to all participants had a prevention efficiency of 23%. The efficiency of targeting prevention based on lower CD4 counts (<200 cells/mL, <350 cells/mL, or <500 cells/mL) and higher viral loads (>100 000 copies/mL and >50 000 copies/mL) was between 10% and 18%. The efficiency of targeting prevention based on number of network connections was much higher (30%-42%). For example, treating the 33 participants with ≥5 connections in 2009 would have theoretically prevented 14 infections in 2010 (42% prevention efficiency). CONCLUSIONS Regular HIV testing of MSM in Beijing can deeply sample the local transmission subnetwork, and targeting prevention efforts based on network connectivity may be an efficient way to deliver prevention interventions.

Comparison of the regulation of β-catenin signaling by type I, type II and type III interferons in hepatocellular carcinoma cells.

Background/Objective IFNs are a group of cytokines that possess potent antiviral and antitumor activities, while β-catenin pathway is a proliferative pathway involved in carcinogenesis. Interaction between these two pathways has not been well elaborated in hepatocellular carcinoma (HCC). Methods HCC cell lines, HepG2 and Huh7, were used in this study. β-catenin protein levels and corresponding signaling activities were observed by flow cytometry and luciferase assay, respectively. Cell proliferation was quantified by counting viable cells under microscope, and apoptosis by TUNEL assay. DKK1 and GSK3β levels were determined by flow cytometry. Secreted DKK1 was tested by ELISA. FLUD, S3I and aDKK1 were used to inhibit STAT1, STAT3 and DKK1 activities, respectively. Results Our findings show that all three types of IFNs, IFNα, IFNγ and IFNλ, are capable of inhibiting β-catenin signaling activity in HepG2 and Huh7 cells, where IFNγ was the strongest (p<0.05). They expressed suppression of cellular proliferation and induced apoptosis. IFNγ expressed greater induction ability when compared to IFNα and IFNλ (p<0.05). All tested IFNs could induce DKK1 activation but not GSK3β in HepG2 and Huh7 cells. IFNs induced STAT1 and STAT3 activation but by using specific inhibitors, we found that only STAT3 is vital for IFN-induced DKK1 activation and apoptosis. In addition, DKK1 inhibitor blocked IFN-induced apoptosis. The pattern of STAT3 activation by different IFNs is found consistent with the levels of apoptosis with the corresponding IFNs (p<0.05). Conclusions In hepatocellular carcinoma, all three types of IFNs are found to induce apoptosis by inhibiting β-catenin signaling pathway via a STAT3- and DKK1-dependent pathway. This finding points to a cross-talk between different IFN types and β-catenin signaling pathways which might be carrying a biological effect not only on HCC, but also on processes where the two pathways bridge.

Perturbations of Monocyte Subsets and Their Association with T Helper Cell Differentiation in Acute and Chronic HIV-1-Infected Patients

Monocytes have been recently subdivided into three subsets: classical (CD14++CD16−), intermediate (CD14++CD16+), and non-classical (CD14+CD16++) subsets, but phenotypic and functional abnormalities of the three monocyte subsets in HIV-1 infection have not been fully characterized, especially in acute HIV-1 infection (AHI). In the study, we explored the dynamic changes of monocyte subsets and their surface markers, and the association between monocyte subsets and the IFN-γ, interleukin (IL)-4, IL-17, and TNF-α producing CD4+ T cells in acute and chronic HIV-1-infected patients. We found that, in the acute HIV-1-infected individuals, the frequency of the intermediate CD14++CD16+ monocyte subsets, the CD163 density and HLA-DR density on intermediate CD14++CD16+ monocytes, and plasma soluble form of CD163 (sCD163) were significantly higher than that in healthy controls. Intermediate CD14++CD16+ monocyte subsets and their HLA-DR expression levels were inversely correlated with the CD4+ T cell counts, and the intermediate CD14++CD16+ monocytes were positively correlated with plasma sCD163. In contrast to the non-classical CD14+CD16++ and classical CD14++CD16− monocyte subsets, the frequency of the intermediate CD14++CD16+ monocytes was positively associated with the frequency of IFN-γ and IL-4 producing CD4+ T cells in HIV-1-infected patients. Taken together, our observations provide new insight into the roles of the monocyte subsets in HIV pathogenesis, particularly during AHI, and our findings may be helpful for the treatment of HIV-related immune activation.

Transmission network characteristics based on env and gag sequences from MSM during acute HIV-1 infection in Beijing, China

Molecular epidemiology can be used to identify human immunodeficiency virus (HIV) transmission clusters, usually using pol sequence for analysis. In the present study, we explored appropriate parameters to construct a simple network using HIV env and gag sequences instead of pol sequences for constructing a phylogenetic tree and a genetic transmission subnetwork, which were used to identify individuals with many potential transmission links and to explore the evolutionary dynamics of the virus among men who have sex with men (MSM) in Beijing. We investigated 70 acute HIV-1 infections, which consisted of HIV-1 subtype B (15.71%), the circulating recombinant forms CRF01_AE (47.14%), CRF07_BC (21.43%), CRF55_01B (1.43%), and CRF65_cpx (4.29%), and an unknown subtype (10.00%). By exploring the similarities and differences among HIV env, gag and pol sequences in describing the dynamics of the HIV-1 CRF01_AE transmission subnetwork among Beijing MSM, we found that four key points of the env sequences (strains E-2011_BJ.CY_16014, E-2011_BJ.FT_16017, E-2011_BJ.TZ_16064, and E-2011_BJ.XW_16035) contained more transmission information than gag sequences (three key points: strains G-2011_BJ.CY_16014, G-2011_BJ.FT_16017, and G-2011_BJ.XW_16035) and pol sequences (two key points: strains P-2011_BJ.CY_16014 and P-2011_BJ.XW_16035). Although the env and gag sequence results were similar to pol sequences in describing the dynamics of the HIV-1 CRF01_AE transmission subnetwork, we were able to obtain more precise information, allowing identification of key points of subnetwork expansion, based on HIV env and gag sequences instead of pol sequences. Taken together, the key points we found will improve our current understanding of how HIV spreads between MSM populations in Beijing and help to better target preventative interventions for promoting public health.

Low Double-Negative CD3+CD4−CD8− T Cells Are Associated with Incomplete Restoration of CD4+ T Cells and Higher Immune Activation in HIV-1 Immunological Non-Responders

Failure of immune reconstitution increases the risk of AIDS or non-AIDS related morbidity and mortality in HIV-1-infected patients. CD3+CD4−CD8− T cells, which are usually described as double-negative (DN) T cells, display CD4-like helper and immunoregulatory functions. Here, we have measured the percentage of DN T cells in the immune reconstituted vs. non-immune reconstituted HIV-1-infected individuals. We observed that immunological non-responders (INRs) had a low number of DN T cells after long-term antiretroviral therapy (ART), and the number of these cells positively correlated with the CD4+ T cell count. The ART did not result in complete suppression of immune activation recorded by the percentage of CD38+HLA-DR+CD8+ T cells in INRs, and a strong inverse correlation was observed between DN T cells and immune activation. A low proportion of TGF-β1+DN T cells was found in INRs. Further mechanism study demonstrated that the level of TGF-β1-producing DN T cells and immune activation had a negative correlation after ART. Taken together, our study suggests that DN T cells control the immunological response in HIV-1-infected patients. These findings expand our understanding of the mechanism of immune reconstitution and could develop specific treatments to return the immune system to homeostasis following initiation of HIV-1 therapy.