Hydroxypropyl-beta-cyclodextrin (HP-BCD) inhibits SARS-CoV-2 replication and virus-induced inflammatory cytokines.

COVID-19 is marked by extensive damage to the respiratory system, often accompanied by systemic manifestations, due to both viral cytopathic effects and hyperinflammatory syndrome. Therefore, the development of new therapeutic strategies or drug repurposing aiming to control virus replication and inflammation are required to mitigate the impact of the disease. Hydroxypropyl-beta-cyclodextrin (HP-BCD) is a cholesterol-sequestering agent with antiviral activity that has been demonstrated against enveloped viruses in in vitro and in vivo experimental models. We also demonstrated that HP-BCD has an immunomodulatory effect, inhibiting the production of selected proinflammatory cytokines induced by microbial products. Importantly, this drug has been used in humans for decades as an excipient in drug delivery systems and as a therapeutic agent in the treatment of Niemann pick C disease. The safety profile for this compound is well established. Here, we investigated whether HP-BCD would affect SARS-CoV-2 replication and virus-induced inflammatory response, using established cell lines and primary human cells. Treating virus or cells with HP-BCD significantly inhibited SARS-CoV-2 replication with a high selective index. A broad activity against distinct SARS-CoV-2 variants was evidenced by a remarkable reduction in the release of infectious particles. The drug did not alter ACE2 surface expression, but affected cholesterol accumulation into intracellular replication complexes, lowering virus RNA and protein levels, and reducing virus-induced cytopathic effects. Virus replication was also impaired by HP-BCD in Calu-3 pulmonary cell line and human primary monocytes, in which not only the virus, but also the production of proinflammatory cytokines were significantly inhibited. Given the pathophysiology of COVID-19 disease, these data indicate that the use HP-BCD, which inhibits both SARS-CoV2 replication and production of proinflammatory cytokines, as a potential COVID-19 therapeutic warrants further investigation.

Hydroxypropyl-Beta-Cyclodextrin Reduces Inflammatory Signaling from Monocytes: Possible Implications for Suppression of HIV Chronic Immune Activation.

Monocytes from HIV-infected patients produce increased levels of inflammatory cytokines, which are associated with chronic immune activation and AIDS progression. Chronic immune activation is often not restored even in patients showing viral suppression under ART. Therefore, new therapeutic strategies to control inflammation and modulate immune activation are required. Hydroxypropyl-beta-cyclodextrin (HP-BCD) is a cholesterol-sequestering agent that has been reported to be safe for human use in numerous pharmaceutical applications and that has been shown to inactivate HIV in vitro and to control SIV infection in vivo Since cellular cholesterol content or metabolism has been related to altered cellular activation, we evaluated whether HP-BCD treatment could modulate monocyte response to inflammatory stimuli. Treatment of monocytes isolated from HIV-positive and HIV-negative donors with HP-BCD inhibited the expression of CD36 and TNF-α after LPS stimulation, independent of raft disruption. Accordingly, HP-BCD-treated cells showed significant reduction of TNF-α and IL-10 secretion, which was associated with lower mRNA expression. LPS-induced p38MAPK phosphorylation was dampened by HP-BCD treatment, indicating this pathway as a target for HP-BCD-mediated anti-inflammatory response. The expression of HLA-DR was also reduced in monocytes and dendritic cells treated with HP-BCD, which could hinder T cell activation by these cells. Our data suggest that, besides its well-known antiviral activity, HP-BCD could have an immunomodulatory effect, leading to decreased inflammatory responses mediated by antigen-presenting cells, which may impact HIV pathogenesis and AIDS progression.IMPORTANCE Chronic immune activation is a hallmark of HIV infection and is often not controlled even in patients under antiretroviral therapy. Indeed, chronic diseases with inflammatory pathogenesis are being reported as major causes of death for HIV-infected persons. Hydroxypropyl-beta cyclodextrin (HP-BCD) is a cholesterol-sequestering drug that inhibits HIV replication and infectivity in vitro and in vivo Recent studies have demonstrated the importance of cholesterol metabolism and content in different inflammatory conditions; therefore, we investigated the potential of HP-BCD as an immunomodulatory drug, regulating the activation of cells from HIV-infected patients. Treatment of monocytes with HP-BCD inhibited the expression and secretion of receptors and mediators that are usually enhanced in HIV patients. Furthermore, we investigated the molecular mechanisms associated with the immunomodulatory effect of HP-BCD. Our results indicate that, besides reducing viral replication, HP-BCD treatment may contribute to modulation of chronic immune activation associated with AIDS.

Viral immunogenicity determines epidemiological fitness in a cohort of DENV-1 infection in Brazil.

The dynamics of dengue virus (DENV) circulation depends on serotype, genotype and lineage replacement and turnover. In São José do Rio Preto, Brazil, we observed that the L6 lineage of DENV-1 (genotype V) remained the dominant circulating lineage even after the introduction of the L1 lineage. We investigated viral fitness and immunogenicity of the L1 and L6 lineages and which factors interfered with the dynamics of DENV epidemics. The results showed a more efficient replicative fitness of L1 over L6 in mosquitoes and in human and non-human primate cell lines. Infections by the L6 lineage were associated with reduced antigenicity, weak B and T cell stimulation and weak host immune system interactions, which were associated with higher viremia. Our data, therefore, demonstrate that reduced viral immunogenicity and consequent greater viremia determined the increased epidemiological fitness of DENV-1 L6 lineage in São José do Rio Preto.

Regulation of HIV-Gag expression and targeting to the endolysosomal/secretory pathway by the luminal domain of lysosomal-associated membrane protein (LAMP-1) enhance Gag-specific immune response.

We have previously demonstrated that a DNA vaccine encoding HIV-p55gag in association with the lysosomal associated membrane protein-1 (LAMP-1) elicited a greater Gag-specific immune response, in comparison to a DNA encoding the native gag. In vitro studies have also demonstrated that LAMP/Gag was highly expressed and was present in MHCII containing compartments in transfected cells. In this study, the mechanisms involved in these processes and the relative contributions of the increased expression and altered traffic for the enhanced immune response were addressed. Cells transfected with plasmid DNA constructs containing p55gag attached to truncated sequences of LAMP-1 showed that the increased expression of gag mRNA required p55gag in frame with at least 741 bp of the LAMP-1 luminal domain. LAMP luminal domain also showed to be essential for Gag traffic through lysosomes and, in this case, the whole sequence was required. Further analysis of the trafficking pathway of the intact LAMP/Gag chimera demonstrated that it was secreted, at least in part, associated with exosome-like vesicles. Immunization of mice with LAMP/gag chimeric plasmids demonstrated that high expression level alone can induce a substantial transient antibody response, but targeting of the antigen to the endolysosomal/secretory pathways was required for establishment of cellular and memory response. The intact LAMP/gag construct induced polyfunctional CD4+ T cell response, which presence at the time of immunization was required for CD8+ T cell priming. LAMP-mediated targeting to endolysosomal/secretory pathway is an important new mechanistic element in LAMP-mediated enhanced immunity with applications to the development of novel anti-HIV vaccines and to general vaccinology field.