Envelope Glycoprotein Gp120 Research Articles

PKG1 promotes the HIV-induced proliferation, migration, and fibrosis of vascular smooth muscle cells of hemorrhoids

BackgroundHemorrhoids are very common in patients with human immunodeficiency virus (HIV) infection. The risk of postoperative infection is significantly greater in HIV-positive patients than in HIV-negative individuals, and the wound healing time is significantly prolonged. This study aimed to investigate the role of HIV-associated hemorrhoids from the perspective of vascular smooth muscle cell (VSMC) function.MethodsA total of 24 hemorrhoid tissue samples (note: grade IV hemorrhoids were absence) were collected and subjected to Masson staining to evaluate fibrosis in this study. mRNA and protein levels were monitored by qPCR and WB analysis, respectively. Immunofluorescence was conducted to evaluate PKG1 and α-SMA expression. To establish a cell model in vitro, VSMCs were stimulated with envelope glycoprotein (gp) 120, which is a type of HIV envelope protein. Cell proliferation was assessed via a CCK-8 assay and EdU staining. Moreover, a wound healing assay was performed to assess cell migration.ResultsOur data confirmed that fibrosis was present in hemorrhoid tissues from HIV-infected patients and that PKG1 expression was upregulated. Moreover, the administration of HIV gp120 promoted the proliferation and migration of VSMCs. Similarly, fibrosis-related markers (α-SMA, MMP2, MMP3, and TIMP1) were markedly upregulated. However, silencing PKG1 inhibited the proliferation, migration, and expression of fibrosis-related markers in gp120-challenged VSMCs.ConclusionThe present research revealed that PKG1 regulated the proliferation, migration, and fibrosis of VSMCs, thereby exerting detrimental effects on HIV-associated hemorrhoids.

Investigating the Effect of GLU283 Protonation State on the Conformational Heterogeneity of CCR5 by Molecular Dynamics Simulations.

CCR5 is a class A GPCR and serves as one of the coreceptors facilitating HIV-1 entry into host cells. This receptor has vital roles in the immune system and is involved in the pathogenesis of different diseases. Various studies were conducted to understand its activation mechanism, including structural studies in which inactive and active states of the receptor were determined in complex with various binding partners. These determined structures provided opportunities to perform molecular dynamics (MD) simulations and to analyze conformational changes observed in the protein structures. The atomic-level dynamic studies allow us to explore the effects of ionizable residues on the receptor. Here, our aim was to investigate the conformational changes in CCR5 when it forms a complex with either the inhibitor maraviroc (MRV), an approved anti-HIV drug, or HIV-1 envelope protein GP120, and compare these changes to the receptor's apo form. In our simulations, we considered both ionized and protonated states of ionizable binding site residue GLU2837.39 in CCR5 as the protonation state of this residue was considered ambiguously in previous studies. Our molecular simulations results suggested that in fact, the change in the protonation state of GLU2837.39 caused interaction profiles to be different between CCR5 and its binding partners, GP120 or MRV. We observed that when the protonated state of GLU2837.39 was considered in complex with the envelope protein GP120, there were substantial structural changes in CCR5, indicating that it adopts a more active-like conformation. On the other hand, CCR5 in complex with MRV always adopted an inactive conformation regardless of the protonation state. Hence, the CCR5 coreceptor displays conformational heterogeneity not only depending on its binding partner but also influenced by the protonation state of the binding site binding site residue GLU2837.39. This outcome is also in accordance with some studies showing that GP120 binding could activate signaling pathways. This outcome could also have significant implications for discovering novel CCR5 inhibitors as anti-HIV drugs using in silico methods such as molecular docking, as it may be necessary to consider the protonated state of GLU2837.39.

Adaptation of the REINVENT neural network architecture to generate potential HIV-1 entry inhibitors

Objectives. The main purpose of this work is to adapt the architecture of the REINVENT neural network to generate potential inhibitors of the HIV-1 envelope protein gp120 using in the learning process with reinforcement of molecular docking on GPUs.Methods. To modify the initial network model, molecular docking on GPUs implemented in the learning process with reinforcement was used, and an algorithm was developed that allows converting the representations of connections generated by the SMILES network into the PDBQT format necessary for docking. To accelerate the learning of the neural network in the modified version of the REINVENT model, the AutoDock-Vina-GPU-2.1 docking program was used, and to clarify the results of its work, the procedure for revaluing the affinity of compounds to the target using the RFScore-4 evaluation function was used.Results. Using a modified version of the REINVENT model, more than 60,000 compounds were obtained, of which about 52,000 molecules have a binding energy value to the HIV-1 gp120 protein comparable to the value calculated for the HIV-1 inhibitor NBD-14204, used in calculations as a positive control. Of the 52,000 compounds selected, about 34,000 molecules satisfy the restrictions imposed on a potential drug to ensure its bioavailability when taken orally.Conclusion. The results obtained allow us to demonstrate the effectiveness of an adapted neural network by the example of designing new potential inhibitors of the gp120 HIV-1 protein capable of blocking the CD4- binding site of the gp120 virus envelope protein and preventing its penetration into host cells.

The Performance of the Current Algorithm of HIV Diagnosis.

We aimed to evaluate the performance of the current algorithm the HIV diagnosis that has been performed for four years. Results of HIV Ag/Ab tests, anti-HIV 1/2 confirmatory tests, HIV-1 RNA tests and the time for official results to be approved were evaluated. The relationship of HIV Ag/Ab tests, anti-HIV 1/2 confirmation tests and HIV-1 RNA PCR tests, their result times and suitability to the algorithm were examined at Izmir Dokuz Eylül University between May 2017 and June 2021. HIV Ag/Ab ELISA was reactive repetitively in 165/54628 (0.30%) serum samples. Anti-HIV 1/2 confirmation test was reactive in 54.42% (80/147) of samples. The most common pattern (18.2%) in the confirmation tests was the positivity of the antibodies against gp160 - gp41 envelope glycoproteins together. The mean reporting time of the confirmation test result was 3h 50 min after the ELISA test. The mean reporting time of the HIV-1 RNA PCR was 12.79 d (±10.22) after the ELISA test and 12.63 (± 10.12) day after the confirmation test. In ROC analysis, the estimated rate of the ELISA test for the confirmation test was highest when S/CO was >13.16 (sensitivity: 97.59 %, specificity: 97.59%). The confirmation test in the current algorithm enabled the rapid test results, early diagnosis of HIV and early antiretroviral therapy. To use the new algorithm effectively, decentralization of the validation tests would be appropriate.

Extracellular vesicle isolation methods identify distinct HIV-1 particles released from chronically infected T-cells.

The current study analyzed the intersecting biophysical, biochemical, and functional propertiesof extracellular particles (EPs) with the human immunodeficiency virus type-1 (HIV-1) beyond the currently accepted size range for HIV-1. We isolated five fractions (Frac-A through Frac-E) from HIV-infected cells by sequential differential ultracentrifugation (DUC). All fractions showed a heterogeneous size distribution with median particle sizes greater than 100nm for Frac-A through Frac-D but not for Frac-E, which contained small EPs with an average size well below 50nm. Synchronized and released cultures contained large infectious EPs in Frac-A, with markers of amphisomes and viral components. Additionally, Frac-E uniquely contained EPs positive for CD63, HSP70, and HIV-1 proteins. Despite its small average size, Frac-E contained membrane-protected viral integrase, detectable only after SDS treatment, indicating that it is enclosed in vesicles. Single particle analysis with dSTORM further supported these findings as CD63, HIV-1 integrase, and the viral surface envelope (Env) glycoprotein (gp) colocalized on the same Frac-E particles. Surprisingly, Frac-E EPs were infectious, and infectivity was significantly reduced by immunodepleting Frac-E with anti-CD63, indicating the presence of this protein on the surface of infectious small EPs in Frac-E. To our knowledge, this is the first time that extracellular vesicle (EV) isolation methods have identified infectious small HIV-1 particles (smHIV-1) that are under 50nm. Collectively, our data indicate that the crossroads between EPs and HIV-1 potentially extend beyond the currently accepted biophysical properties of HIV-1, which may have further implications for viral pathogenesis.

The sensitivity of HIV-1 gp120 polymorphs to inhibition by temsavir correlates to temsavir binding on-rate

Temsavir binds directly to the HIV-1 envelope glycoprotein gp120 and selectively inhibits interactions between HIV-1 and CD4 receptors. Previous studies identified gp120 amino acid positions where substitutions are associated with reduced susceptibility to temsavir. The mechanism by which temsavir susceptibility is altered in these envelope glycoproteins was evaluated. Pseudoviruses encoding gp120 substitutions alone (S375H/I/M/N, M426L, M434I, M475I) or in combination (S375H + M475I) were engineered on a wild-type JRFL background. Temsavir-gp120 and CD4-gp120 binding kinetics and ability of temsavir to block CD4-gp120 binding were evaluated using the purified polymorphic gp120 proteins and a Creoptix® WAVE Delta grating-coupled interferometry system. Fold-change in half-maximal inhibitory concentration (IC50) in JRFL-based pseudoviruses containing the aforementioned polymorphisms relative to that of wild-type ranged from 4-fold to 29,726-fold, while temsavir binding affinity for the polymorphic gp120 proteins varied from 0.7-fold to 73.7-fold relative to wild-type gp120. Strong correlations between temsavir IC50 and temsavir binding affinity (r = 0.7332; P = 0.0246) as well as temsavir binding on-rate (r = −0.8940; P = 0.0011) were observed. Binding affinity of gp120 proteins for CD4 varied between 0.4-fold and 3.1-fold compared with wild-type gp120; no correlations between temsavir IC50 and CD4 binding kinetic parameters were observed. For all polymorphic gp120 proteins, temsavir was able to fully block CD4 binding; 3 polymorphs required higher temsavir concentrations. Loss of susceptibility to temsavir observed for gp120 polymorphisms strongly correlated with reductions in temsavir binding on-rate. Nonetheless, temsavir retained the ability to fully block CD4-gp120 engagement given sufficiently high concentrations.

Scyllatoxin-based peptide design for E. coli expression and HIV gp120 binding

Targeting the hydrophobic Phe43 pocket of HIV's envelope glycoprotein gp120 is a critical strategy for antiviral interventions due to its role in interacting with the host cell's CD4. Previous inhibitors, including small molecules and CD4 mimetic peptides based on scyllatoxin, have demonstrated significant binding and neutralization capabilities but were often chemically synthesized or contained non-canonical amino acids. Microbial expression using natural amino acids offers advantages such as cost-effectiveness, scalability, and efficient production of fusion proteins. In this study, we enhanced the previous scyllatoxin-based synthetic peptide by substituting natural amino acids and successfully expressed it in E. coli. The peptide was optimized by mutating the C-terminal amidated valine to valine and glutamine, and by reducing the disulfide bonds from three to two. Circular dichroism confirmed proper secondary structure formation, and fluorescence polarization analysis revealed specific, concentration-dependent binding to HIV gp120, supported by molecular dynamics simulations. These findings indicate the potential for scalable microbial production of effective antiviral peptides, with significant applications in pharmaceutical development for HIV treatment.

∆9-THC attenuates neurodegeneration seen in HIV-gp120 transgenic mice through downregulation of microglial cell activation, astrocytosis and by reversing gut dysbiosis

Abstract The GFAP-gp120Tg mice express soluble HIV-envelope protein gp120 in astrocytes and share many neuropathological features observed in the CNS of AIDS patients. Here, we investigated the effect of a cannabinoid, ∆9-THC, on gp120-mediated neuroinflammation and progression of neurodegeneration. We treated groups of GFAP-gp120Tg and C57/BL6 WT mice with ∆9-THC or the vehicle. Immunofluorescence imaging, flow cytometry, snRNA-sequencing, and shotgun sequencing were performed to understand the cellular and molecular level incidents. ∆9-THC reduced the neuroinflammation driven by gp120 by down-regulating the inflammatory chemokine receptors such as CCR5, CXCR4 on immune cells that directly access the CNS. Pronounced astrocytosis and microglial activation seen in Tg mice was significantly reduced following treatment with ∆9-THC. Neuroglial gene expression was also reversed after ∆9-THC treatment. Tg mice exhibited significant gut microbiota dysbiosis which was reversed by ∆9-THC. Members of the genera Alistipes, Prevotella, Plasmodium, Helicobacter, Desulfovibrio had higher relative abundance in Tg mice but reduced after ∆9-THC treatment. Taken together, this study demonstrates that ∆9-THC treatment significantly improves HIV-gp120-mediated pathogenesis of neurodegeneration, neuroinflammation, and helps to reshape gut microbiota (This work was supported in part by NIH grants R01ES030144, P01AT003961, P20GM103641, and R01AI123947, R01AI160896).

The Global Impact of HIV: A Comprehensive Review

The Human Immunodeficiency Virus (HIV) has been a significant global health challenge since its discovery in the 1980s, leading to the devastating Acquired Immunodeficiency Syndrome (AIDS). Despite advancements in medical research and antiretroviral therapies, HIV/AIDS remains a pressing public health concern, particularly in resource-limited regions. This comprehensive review provides updated data and scientific insights on the global impact of HIV, shedding light on the current state of the epidemic and the challenges faced in combating it. The review highlights the resurgence of HIV cases in Eastern European countries, such as Ukraine, Estonia, and Latvia, with surprising increases in AIDS cases observed in East Asian countries. However, it is in sub-Saharan Africa that the burden of HIV remains most acute, with high prevalence rates and a significant number of affected individuals. The region requires continued attention and resources to address the complex challenges associated with HIV prevention, treatment, and care. The article delves into the classification and structure of HIV, emphasizing its belonging to the Lentivirinae subfamily, specifically HIV-1 and HIV-2. HIV-1, the predominant viral species globally, exhibits a distinct clinical latency phase, contributing to its persistence and infectivity. The high replication rate and genetic variability of HIV, driven by the error-prone reverse transcriptase enzyme, result in the emergence of diverse subtypes and strains across different regions. Furthermore, the article explores the structural components of HIV-1, including the envelope glycoproteins (gp120 and gp41), matrix protein, and various enzymes critical to the viral life cycle. Despite progress in medical research and access to antiretroviral therapies, HIV/AIDS continues to present challenges such as limited resources, drug resistance, and regional disparities.

Effects of intrinsically disordered regions in gp120 underlying HIV neutralization phenotypes

HIV envelope protein gp120 is considered a primary molecular determinant of viral neutralization phenotype due to its critical role in viral entry and immune evasion. The intrinsically disordered regions (IDRs) in gp120 are responsible for their extensive sequence variations and significant structural rearrangements. Despite HIV neutralization phenotype and sequence/structural information of gp120 have been experimentally characterized, there remains a gap in our understanding of the correlation between the viral phenotype and IDRs in gp120. Here, we combined machine learning (ML) techniques and molecular dynamics (MD) simulations to gain data-driven and molecule-mechanism insights into relationships between viral sequence, structure, and phenotypes from the perspective of IDRs in gp120. ML models, trained only on the length and disorder score of IDRs, achieved equivalent performance to the best baseline model using amino acid sequences to discriminate HIV neutralization phenotype, indicating that the lengths or disorder of specific IDRs are strongly related to HIV neutralization phenotypes. Comparative MD analysis reveals that gp120 with extreme neutralization phenotypes in multiple conformational states, especially some IDRs, exhibit significantly distinct structural dynamics, conformational flexibility, and thermodynamic distributions. Taken together, our study provided insights into the role of IDRs in gp120 responding to HIV neutralization phenotypes, which will advance the understanding of molecular mechanisms underlying viral function associated with HIV neutralization phenotype and help develop antiviral vaccines or drugs.

Gp120-derived amyloidogenic peptides form amyloid fibrils that increase HIV-1 infectivity.

Apart from mediating viral entry, the function of the free HIV-1 envelope protein (gp120) has yet to be elucidated. Our group previously showed that EP2 derived from one β-strand in gp120 can form amyloid fibrils that increase HIV-1 infectivity. Importantly, gp120 contains ~30 β-strands. We examined whether gp120 might serve as a precursor protein for the proteolytic release of amyloidogenic fragments that form amyloid fibrils, thereby promoting viral infection. Peptide array scanning, enzyme degradation assays, and viral infection experiments in vitro confirmed that many β-stranded peptides derived from gp120 can indeed form amyloid fibrils that increase HIV-1 infectivity. These gp120-derived amyloidogenic peptides, or GAPs, which were confirmed to form amyloid fibrils, were termed gp120-derived enhancers of viral infection (GEVIs). GEVIs specifically capture HIV-1 virions and promote their attachment to target cells, thereby increasing HIV-1 infectivity. Different GAPs can cross-interact to form heterogeneous fibrils that retain the ability to increase HIV-1 infectivity. GEVIs even suppressed the antiviral activity of a panel of antiretroviral agents. Notably, endogenous GAPs and GEVIs were found in the lymphatic fluid, lymph nodes, and cerebrospinal fluid (CSF) of AIDS patients in vivo. Overall, gp120-derived amyloid fibrils might play a crucial role in the process of HIV-1 infectivity and thus represent novel targets for anti-HIV therapeutics.

Interferon-β deficiency alters brain response to chronic HIV-1 envelope protein exposure in a transgenic model of NeuroHIV

Human immunodeficiency virus-1 (HIV-1) infects the central nervous system (CNS) and causes HIV-associated neurocognitive disorders (HAND) in about half of the population living with the virus despite combination anti-retroviral therapy (cART). HIV-1 activates the innate immune system, including the production of type 1 interferons (IFNs) α and β. Transgenic mice expressing HIV-1 envelope glycoprotein gp120 (HIVgp120tg) in the CNS develop memory impairment and share key neuropathological features and differential CNS gene expression with HIV patients, including the induction of IFN-stimulated genes (ISG). Here we show that knocking out IFNβ (IFNβKO) in HIVgp120tg and non-tg control mice impairs recognition and spatial memory, but does not affect anxiety-like behavior, locomotion, or vision. The neuropathology of HIVgp120tg mice is only moderately affected by the KO of IFNβ but in a sex-dependent fashion. Notably, in cerebral cortex of IFNβKO animals presynaptic terminals are reduced in males while neuronal dendrites are reduced in females. The IFNβKO results in the hippocampal CA1 region of both male and female HIVgp120tg mice in an ameliorated loss of neuronal presynaptic terminals but no protection of neuronal dendrites. Only female IFNβ-deficient HIVgp120tg mice display diminished microglial activation in cortex and hippocampus and increased astrocytosis in hippocampus compared to their IFNβ-expressing counterparts. RNA expression for some immune genes and ISGs is also affected in a sex-dependent way. The IFNβKO abrogates or diminishes the induction of MX1, DDX58, IRF7 and IRF9 in HIVgp120tg brains of both sexes. Expression analysis of neurotransmission related genes reveals an influence of IFNβ on multiple components with more pronounced changes in IFNβKO females. In contrast, the effects of IFNβKO on MAPK activities are independent of sex with pronounced reduction of active ERK1/2 but also of active p38 in the HIVgp120tg brain. In summary, our findings show that the absence of IFNβ impairs memory dependent behavior and modulates neuropathology in HIVgp120tg brains, indicating that its absence may facilitate development of HAND. Moreover, our data suggests that endogenous IFNβ plays a vital role in maintaining neuronal homeostasis and memory function.

HIV-1 gp120 amplifies astrocyte elevated gene-1 activity to compromise the integrity of the outer blood-retinal barrier.

This study aims to investigate the functions and mechanistic pathways of Astrocyte Elevated Gene-1 (AEG-1) in the disruption of the blood-retinal barrier (BRB) caused by the HIV-1 envelope glycoprotein gp120. We utilized ARPE-19 cells challenged with gp120 as our model system. Several analytical techniques were employed to decipher the intricate interactions at play. These included PCR, Western blot, and immunofluorescence assays for the molecular characterization, and transendothelial electrical resistance (TEER) measurements to evaluate barrier integrity. We observed that AEG-1 expression was elevated, whereas the expression levels of tight junction proteins ZO-1, Occludin, and Claudin5 were downregulated in gp120-challenged cells. TEER measurements corroborated these findings, indicating barrier dysfunction. Additional mechanistic studies revealed that the activation of NFκB and MMP2/9 pathways mediated the AEG-1-induced barrier destabilization. Through the use of lentiviral vectors, we engineered cell lines with modulated AEG-1 expression levels. Silencing AEG-1 alleviated gp120-induced downregulation of tight junction proteins and barrier impairment while concurrently inhibiting the NFκB and MMP2/9 pathways. Conversely, overexpression of AEG-1 exacerbated these pathological changes, further compromising the integrity of the BRB. Gp120 upregulates the expression of AEG-1 and activates the NFκB and MMP2/9 pathways. This in turn leads to the downregulation of tight junction proteins, resulting in the disruption of barrier function.

ADS-J21 is a novel HIV-1 entry inhibitor targeting gp41

HIV-1 envelope glycoprotein gp41 mediates fusion between HIV-1 and host cell membranes, making inhibitors of gp41 attractive anti-HIV drugs. We previously reported an efficient HIV-1 fusion inhibitor, ADS-J1, with a Y-shaped structure. Here, we discovered a new compound, ADS-J21, with a Y-shaped structure similar to that of ADS-J1 but with a lower molecular weight. Moreover, ADS-J21 exhibited effective anti-HIV-1 activity against divergent HIV-1 strains in vitro, including several HIV-1 laboratory-adapted strains and primary isolates with different subtypes (clades A to F) and tropisms (X4 or R5). Mechanistic studies have demonstrated that ADS-J21 blocks the formation of the gp41 six-helix bundle (6-HB) by targeting conserved amino acids Lys35 and Trp32. These findings suggest that ADS-J21 can be used as a new lead compound for further optimization in the development of a small-molecule fusion inhibitor.

Design and sustainable synthesis of small mannose-based glycodendrons as ligands for HIV-1 envelope protein gp120: Toward an explanation for their binding

On the basis of the interesting properties that glucuronic acid-based glycodendrimers and glycodendrons show against Dengue virus through their interaction with its envelope protein, herein we describe the design, sustainable synthesis and anti HIV-1 evaluation of a series of mannose-based glycodendrimers bearing different scaffolds, valency and functional groups at the focal position. Their sustainable chemical synthesis was performed using microwave-assisted copper(I) catalyzed azide-alkyne cycloaddition (CuAAC) reaction to yield glycoconjugates with full conversions (99%), allowing the reduction of the reaction time from 16 h to 60–120 min. Surface plasmon resonance studies have demonstrated that the small mannose-based glycodendrons (divalent derivatives) give the best binding interactions with the HIV-1 gp120 envelope protein, being the most active those that have a methoxymethyl group or an azidomethyl group at the focal position. Molecular modeling studies were carried out to simulate and explain the binding observed by surface plasmon resonance. This work reports a sustainable synthesis of small mannose-based glycodendrons as novel and potent anti HIV lead compounds.

Preliminary Study on the Role of Kynurenic Acid in Inhibiting the Physiological Changes of Astrocyte Induced By HIV-1 Envelope Protein gp120

Background Since the introduction of combined antiretroviral therapy, acquired immunodeficiency syndrome (AIDS) caused by human immunodeficiency virus (HIV) has transformed from an incurable fatal disease to a chronic treatable disease. HIV-associated neurocognitive disorder (HAND) is a common long-term complication of AIDS. Astrocytes are believed to play an essential role in the development of HAND. Therefore this study aims to find out how astrocytes change and how to resist this change in the process of hand. Methods Cortical astrocytes were dissected from Sprague-Dawley (SD) neonatal rats (1-3 days) with the aseptic operation and digested with 0.25% trypsin 37℃ for 20 min. The cell suspension was dispersed through the cell strainer and seeded into the poly-D-lysine coated T-75 flasks supplemented with 10% FBS and 1% penicillin/streptomycin. After ten days of incubation, the cells were purified in a shaking incubator (250 r/min) at 37℃ for 24 h, and astrocytes were cultured at desired densities in 6-well plates. The cells were identified as >98% pure astrocytes by Cy3-conjugated GFAP immunostaining. Cultured astrocytes were treated with 150 pM HIV-1 gp120 CM for 12 h before applying 5 or 25 μM kynurenic acid(KYNA) for 12 h. Afterward, western blotting technology was used to detect the expression levels of different proteins in each group, and Fuji Image J software was used to analyze the bands. Results Compared with the control group, the expression levels of AKT, PI3K and P62 proteins in astrocyte of mice added with gp120 were significantly reduced, which were 38%, 41% and 40%, respectively, while KYNA alone had no significant change; Compared with the addition of gp120 group, the trend of decreased AKT (P<0.05) and PI3K protein expression was inhibited when both gp120 and KYNA were added, with an increase of 43% and 52%, respectively. We observed that the expression level of p-AKT had a similar trend but the expression level of p-PI3K had an opposite trend. This suggests that the effect of gp120 on the PI3K/AKT pathway may have begun with an upregulation of PI3K activation levels. Conclusion HIV-1 gp120 can cause changes in the physiological status of astrocytes, and KYNA can counteract this change, which indicates that KYNA may have a potential therapeutic effect on HAND. ( Acknowledgements:National Natural Science Foundation of China, No. 82172259 to H.C.; Undergraduate Training Program for Innovation and Entrepreneurship of SMU, China, No. 202212121247; Corresponding author: Hong Cao, gzhcao@smu.edu.cn ) Keywords：HIV-1 gp120, Kynurenic acid, Astrocyte, AKT, PI3K disorder

Prebiotic Mannan Oligosaccharide Attenuates Cognitive and Behavioral Disorders in HIV-1 gp120 Transgenic Mouse Via the Microbiota-Gut-Brain Axis

Background The prevalence of HIV-associated neurocognitive disorders (HAND) remains high among HIV-1 infected patients, despite significant advances in antiretroviral therapy (HAART). HAND is characterized by clinical symptoms such as motor and attention deficits, impaired learning and memory, and in severe cases, dementia. The HIV-1 envelope protein gp120 is believed to have a crucial role in the development of these disorders HIV-1-related neurocognitive dysfunction is strongly linked to the host inflammatory regulator α7 nicotinic acetylcholine receptor (A7R) and the signaling of highly reactive oxygen species (ROS). A7R plays a crucial role in regulating calcium ion exchange in nerve cells, immune cells, and endothelial cells. In the brain, antioxidants are present to control and prevent the formation of harmful ROS, which further contribute to the severity of neurodegeneration. Assessing ROS can help predict oxidative tissue damage, including modifications in proteins, lipids, or DNA. ROS tend to accumulate in the small and large intestines, leading to oxidative stress and affecting cognitive function. The prebiotic mangan oligosaccharide (MOS) has been reported to reshape the gut microbiome and increase short-chain fatty acid (SCFAs) production. This, in turn, alters neuronal redox status through the gut-brain axis. There may be a critical role for HIV-1 gp120 (Gp120) protein in these disorders. The microbiota-gut-brain (MGB) axis is bidirectional, and gut microbiota influence brain disorders including HAND, which could be targeted by nutritional interventions. Methods: The HIV-1 gp120 transgenic mice (Gp120 transgenic mice), and wild-type (WT) mice were randomly divided into 4 groups (9 months old, n=6 per group): WT group, WT+MOS group, Gp120 transgenic group, Gp120 transgenic + MOS group. All MOS group mice were administered the prebiotic MOS (0.12% w/v in the drinking water).The drinking water added MOS or was replaced twice a week for 8 weeks and recorded water intake. In the in vitro cell experiment, the cortex of neonatal Sprague-Dawley (SD) rats (1-3 days) was dissected to prepare astrocytes. Cells were identified using Cy3-conjugated GFAP immunostaining. Cultured astrocytes were treated with 300 pM Gp120 protein for 24 hours, and then 0.2, 2, 20 or 200 μM MOS was applied for 24 hours, and different proteins level of expression were detected by Western blot. The ROS level were then analyzed on FACS Calibur-Tangerine flow cytometry in 502 nm. The alteration in mitochondrial membrane potential in astrocytes was assessed through the utilization of the JC-1 Assay Kit in mPMs. Results: As a result of treatment with MOS, the redox status of the brain and the neuroinflammatory responses were significantly balanced. Through correlation analysis, it was observed that a modified gut microbiome and increased butyrate production had a significant impact on behavioral changes and brain oxidative status. Our findings suggest that MOS could mitigate cognitive and behavioral disorders in the Gp120 transgenic mouse. MOS achieves this by suppressing Gp120-induced chronic inflammation and dysregulated production of reactive oxygen species (ROS), thereby improving HIV-1-related neurocognitive dysfunction. This is achieved by targeting A7R and intestinal ROS signaling. Additionally, our results indicate that SCFA supplementation in the brain of HAND mice alleviated behavioral disorders and balanced the HPA-axis and redox status. Conclusion: Overall, the present study demonstrated that MOS significantly reduced cognitive and mental deficits in Gp120 transgenic mice. As prebiotics, MOS could be translated into novel microbiota-targeted approaches to manage metabolic and neurodegenerative diseases. ( Acknowledgements: Natural Science Foundation of Guangdong Province, No. 208059478058 to H.C.; Corresponding author: Hong Cao, gzhcao@smu.edu.cn ) Keywords：HIV-1 gp120, mangan oligosaccharide, α7nAChR, reactive oxygen species

HIV-1 gp120-Induced Cognitive Disorder Is Concomitant with Altered Gut Microbiota

Background HIV-associated neurocognitive disorders (HAND) is an essential factor affecting the quality of life of people living with HIV (PLWH), and the prevalence of HAND in PLWH can reach 19% to 64%. More than 50% of HAND patients treated with highly active antiretroviral therapy (HAART) did not show improvement in symptoms of cognitive impairment. HIV-1 envelope protein gp120 may be a major contributor to HAND pathology. HIV-1 gp120 enters neurons by binding CXCR4 and CCR5 and can also bind neuronal tubulin to cause direct neurotoxicity and neuronal death. HIV-1 gp120 transgenic mice (Tgm) are commonly used as HAND animal models, and Tgm brain pathological changes and differential gene expression are highly consistent with HAND patients. Intestinal flora affects the progression of diseases by regulatory the intestinal barrier, and several studies have confirmed that the normalization of abnormal intestinal flora reduces the damage to the nervous system in a variety of neurodegenerative diseases. Studies reported that Akkermansia muciniphila has a downward trend in PLWH, which may cause intestinal barrier damage. There is still a lack of relevant evidence to confirm the association between abnormal changes in gut microbiota and HAND induced by HIV-1 gp120. Therefore, in this study, we examined the gut microbiota changes in 6, 9, and 12 months Tgm to explore the relationship between age-dependent significantly different bacterial genera, intestinal barrier and neuronal damage. Methods The fresh feces were collected from HIV-1 gp120 transgenic mice (Tgm) and C57BL/6J mice (wild type, WT) at ages 6, 9, and 12 months using perianal stimulation at the same time (n=5). Total bacterial DNA was extracted from each fecal sample and the V3-V4 region of 16S rRNA was sequenced by the Illumina MiSeq platform. 12 months Tg and WT mice were sacrificed, and serum was collected to detect lipopolysaccharide (LPS) concentration by ELISA, and brain tissue of mice in each group was collected for Map2 immunohistochemical staining (n=5). SPSS 20.0 software was used for statistical analysis. P <0.05 were considered statistically significant. Results 16S rRNA analysis showed that increased age was significantly associated with increased abundance of Blautia ( P <0.01) and Prevotellaceae_NK3B31_group ( P <0.0001) genus and decreased abundance of Akkermansia genus ( P <0.05) in Tgm. Notably, the increasing age of WT was associated with the opposite trend of Blautia, Prevotellaceae_NK3B31_group and Akkermansia genus abundance, indicating those genus changes with age and gp120 induced. To further explore the effect of gut microbiota on the gut barrier, serum LPS concentrations were detected for 12 months Tgm and WT. The results showed that serum LPS level was significantly higher in Tgm than in WT ( P <0.01), indicating that the intestinal barrier may be impaired in Tgm. Finally, we collected 12 months Tgm and WT brain tissues for Map2 immunohistochemical staining to evaluate neuronal synaptic length and integrity. Compared with WT, the expression of map2 in the hippocampus and cerebral cortex was significantly decreased ( P <0.05), indicating neuronal damage in Tgm. Conclusion At the genus level, the abundance of Akkermansia was negatively correlated and the Blautia and Prevotellaceae_NK3B31_group abundance was positively correlated with increasing age in Tgm but showed an opposite trend in WT. The serum LPS level increased dramatically in the 12 months Tgm, indicating Tgm with intestinal barrier damage. Map2 expression was reduced considerably hippocampus and cortex in Tgm brain, which means neuronal synaptic integrity was impaired. ( Acknowledgements: National Natural Science Foundation of China, No. 82172259 to H.C.; Corresponding author: Hong Cao, gzhcao@smu.edu.cn.)

GP120 and tenofovir alafenamide alter cannabinoid receptor 1 expression in hippocampus of mice

Central nervous system (CNS) dysfunction remains prevalent in people with HIV (PWH) despite effective antiretroviral therapy (ART). There is evidence that low-level HIV infection and ART drugs may contribute to CNS damage in the brain of PWH with suppressed viral loads. As cannabis is used at a higher rate in PWH compared to the general population, there is interest in understanding how HIV proteins and ART drugs interact with the endocannabinoid system (ECS) and inflammation in the CNS. Therefore, we investigated the effects of the HIV envelope protein gp120 and tenofovir alafenamide (TAF) on cannabinoid receptor 1 (CB1R), glial fibrillary acidic protein (GFAP), and IBA1 in the brain and on locomotor activity in mice. The gp120 transgenic (tg) mouse model was administered TAF daily for 30 days and then analyzed using the open field test before being euthanized, and their brains were analyzed for CB1R, GFAP, and IBA1 expression using immunohistochemical approaches. CB1R expression levels were significantly increased in CA1, CA2/3, and dentate gyrus of gp120tg mice compared to wt littermates; TAF reversed these effects. As expected, TAF showed a medium effect of enhancing GFAP in the frontal cortex of gp120tg mice in the frontal cortex. TAF had minimal effect on IBA1 signal. TAF showed medium to large effects on fine movements, rearing, total activity, total distance, and lateral activity in the open-field test. These findings suggest that TAF may reverse gp120-induced effects on CB1R expression and, unlike tenofovir disoproxil fumarate (TDF), may not affect gliosis in the brain.

An HIV-1/HIV-2 Chimeric Envelope Glycoprotein Generates Binding and Neutralising Antibodies against HIV-1 and HIV-2 Isolates.

The development of immunogens that elicit broadly reactive neutralising antibodies (bNAbs) is the highest priority for an HIV vaccine. We have shown that a prime-boost vaccination strategy with vaccinia virus expressing the envelope glycoprotein gp120 of HIV-2 and a polypeptide comprising the envelope regions C2, V3 and C3 elicits bNAbs against HIV-2. We hypothesised that a chimeric envelope gp120 containing the C2, V3 and C3 regions of HIV-2 and the remaining parts of HIV-1 would elicit a neutralising response against HIV-1 and HIV-2. This chimeric envelope was synthesised and expressed in vaccinia virus. Balb/c mice primed with the recombinant vaccinia virus and boosted with an HIV-2 C2V3C3 polypeptide or monomeric gp120 from a CRF01_AG HIV-1 isolate produced antibodies that neutralised >60% (serum dilution 1:40) of a primary HIV-2 isolate. Four out of nine mice also produced antibodies that neutralised at least one HIV-1 isolate. Neutralising epitope specificity was assessed using a panel of HIV-1 TRO.11 pseudoviruses with key neutralising epitopes disrupted by alanine substitution (N160A in V2; N278A in the CD4 binding site region; N332A in the high mannose patch). The neutralisation of the mutant pseudoviruses was reduced or abolished in one mouse, suggesting that neutralising antibodies target the three major neutralising epitopes in the HIV-1 envelope gp120. These results provide proof of concept for chimeric HIV-1/HIV-2 envelope glycoproteins as vaccine immunogens that can direct the antibody response against neutralising epitopes in the HIV-1 and HIV-2 surface glycoproteins.