HIV-1 infection and latency-reversing agents bryostatin-1 and JQ1 disrupt amyloid beta homeostasis in human astrocytes.

Since the introduction of the combined antiretroviral therapy, HIV-1 infection has become a manageable chronic disease in which patients display a life expectancy almost identical to the general population. Nevertheless, various age-related pathologies such as neurocognitive disorders have emerged as serious complications. A "shock and kill" strategy using latency-reversing agents (LRA) to reactivate HIV-1 has been proposed to eliminate the viral reservoir in such chronically infected patients. However, the impact of LRA on the central nervous system remains elusive. Given that an increased amyloid beta (Aß) deposition is a feature of HIV-1-infected brains, we investigated the consequences of HIV-1 infection and treatment with two LRA (bryostatin-1 and JQ1) on the capacity of human astrocytes to engulf and clear Aß. We show here that HIV-1-infected astrocytes accumulate a very high amount of Aß compared to uninfected cells, but the engulfed peptide in degraded very slowly. The LRA bryostatin-1 induces a reduction in Aß endocytosis, whereas JQ1 treatment results in a very slow degradation of the ingested material associated with a reduced expression of the endopeptidase neprilysin. An exposure to JQ1 also induces a sustained release of Aß-loaded microvesicles. Thus, both HIV-1 infection and treatment with some LRA could contribute to the reported Aß accumulation in the brain of HIV-1-infected persons.

Astrocytes sustain long-term productive HIV-1 infection without establishment of reactivable viral latency.

The "shock and kill" HIV-1 cure strategy proposes eradication of stable cellular reservoirs by clinical treatment with latency-reversing agents (LRAs). Although resting CD4+ T cells latently infected with HIV-1 constitute the main reservoir that is targeted by these approaches, their consequences on other reservoirs such as the central nervous system are still unknown and should be taken into consideration. We performed experiments aimed at defining the possible role of astrocytes in HIV-1 persistence in the brain and the effect of LRA treatments on this viral sanctuary. We first demonstrate that the diminished HIV-1 production in a proliferating astrocyte culture is due to a reduced proliferative capacity of virus-infected cells compared with uninfected astrocytes. In contrast, infection of non-proliferating astrocytes led to a robust HIV-1 infection that was sustained for over 60 days. To identify astrocytes latently infected with HIV-1, we designed a new dual-color reporter virus called NL4.3 eGFP-IRES-Crimson that is fully infectious and encodes for all viral proteins. Although we detected a small fraction of astrocytes carrying silent HIV-1 proviruses, we did not observe any reactivation using various LRAs and even strong inducers such as tumor necrosis factor, thus suggesting that these proviruses were either not transcriptionally competent or in a state of deep latency. Our findings imply that astrocytes might not constitute a latent reservoir per se but that relentless virus production by this brain cell population could contribute to the neurological disorders seen in HIV-1-infected persons subjected to combination antiretroviral therapy.

Contrasting effect of the latency-reversing agents bryostatin-1 and JQ1 on astrocyte-mediated neuroinflammation and brain neutrophil invasion.

BACKGROUND: Despite effectiveness of the combined antiretroviral therapy, HIV-1 persists in long-lived latently infected cells. Consequently, new therapeutic approaches aimed at eliminating this latent reservoir are currently being developed. A "shock and kill" strategy using latency-reversing agents (LRA) to reactivate HIV-1 has been proposed. However, the impact of LRA on the central nervous system (CNS) remains elusive. METHODS: We used human fetal astrocytes and investigated the effects of several LRA on their functional and secretory activities. Astrocytes were infected with VSV-G-pseudotyped HIV-1 before treatment with various blood-brain barrier (BBB)-permeable LRA at subcytotoxic doses, which allow HIV-1 reactivation based on previous in vitro and clinical studies. Cells and supernatants were then used to evaluate effects of infection and LRA on (i) viability and metabolic activity of astrocytes using a colorimetric MTS assay; (ii) chemokines and proinflammatory cytokines secretion and gene expression by astrocytes using ELISA and RT-qPCR, respectively; (iii) expression of complement component 3 (C3), a proxy for astrogliosis, by RT-qPCR; (iv) glutamate uptake capacity by a fluorometric assay; and (v) modulation of neutrophil transmigration across an in vitro BBB model. RESULTS: We demonstrate that bryostatin-1 induces secretion of chemokines CCL2 and IL-8 and proinflammatory cytokines IL-6 and GM-CSF, whereas their production is repressed by JQ1. Bryostatin-1 also increases expression of complement component 3 and perturbs astrocyte glutamate homeostasis. Lastly, bryostatin-1 enhances transmigration of neutrophils across an in vitro blood-brain barrier model and induces formation of neutrophil extracellular traps. CONCLUSIONS: These observations highlight the need to carefully assess the potential harmful effect to the CNS when selecting LRA for HIV-1 reactivation strategies.

Minute observations and theoretical framework of Darwin's studies on climbing plants.

The role of movement in plants was unrecognised for a long time, due to the relative slowness of such movements by comparison with those of active animals such as insects and vertebrates, and to the difficulty with which they are distinguished from mere growth processes. Given this, the pioneer work of Darwin (On the Movements and Habits of Climbing Plants1865) is a milestone in botany. It is always cited as the beginning of any rigorous analysis of plant movement. Such a successful approach results at once from Darwin's broad knowledge of natural history, his use of numerous direct observations and simple experiments, but also from his own talent, which compensated for technical gaps in several instances. His use of metaphorical descriptions was a response to the lack of a firm theoretical background. It facilitated a preliminary classification of plant movement and a comparison of observations. Perhaps his most fruitful metaphors were those drawn from economic concepts, such as division of labour. Darwin's legacy in plant physiology is impressive, as even the most recent biophysical interpretations of climbing plants (e.g. tendril perversion) take place inside the framework he constructed.

Safety, tolerance and acceptability of the Invisible Condom and its vaginal applicator in healthy women and their male sexual partners.

OBJECTIVES: The study was conducted to evaluate the safety and acceptability of the Invisible Condom when applied once or twice daily for 14 days in healthy women and their male sexual partners. STUDY DESIGN: Forty-one women and 23 men divided into three cohorts were enrolled. Cohort 1:14 sexually abstinent women applying gel twice daily for 14 days; Cohort 2:14 sexually active women with tubal ligation applying gel once daily for 14 days and their 14 sexual partners who did not use gel; Cohort 3:13 women on oral contraceptive applying gel once daily for 14 days and 9 of their sexual partners. RESULTS: No serious adverse events (AEs) were reported. Colposcopy showed no genital ulceration nor epithelial lesions. No major changes in vaginal flora or vaginal pH were detected. None of the women had to stop product application because of AEs. The majority of AEs were mild. Common AEs were itching, dryness, burning sensation, erythema and discharge. Satisfaction questionnaire showed that the gel and applicator were acceptable. CONCLUSION: The Invisible Condom and applicator were safe, well tolerated and acceptable when applied intravaginally for 14 days. Thus, expanded safety and effectiveness evaluation is warranted.