Reactivation of latent HIV-1 in vitro using an ethanolic extract from Euphorbia umbellata (Euphorbiaceae) latex

The interconnection between periodontitis and HIV-1 latency: Molecular mechanisms and therapeutic insights

Periodontitis is one of the major global public health problems associated with the occurrence and development of diverse systemic diseases, especially acquired immune deficiency syndrome (AIDS), necessitating further research and clinical attention. The persistence of HIV-1 latency poses a significant challenge to the attainment of a functional cure for AIDS, despite the introduction of highly active antiretroviral therapy (HAART). A similar mechanistic basis between periodontitis and HIV-1 latency has been revealed by many studies, suggesting possible mechanisms whereby periodontitis and HIV-1 latency may mutually influence each other. Therefore, we aimed to systematically summarize the current research on periodontitis and HIV-1 latency to investigate their potential correlations. This study revealed several common hubs for periodontitis and HIV-1 latency in the nuclear factor kappa-B (NF-κB) signaling pathway and other signaling pathways, including the Wnt/β-catenin pathway, bromodomain-containing protein 4 (BRD4), protein kinase C (PKC), the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome, programmed cell death protein 1 (PD-1), histone deacetylases (HDACs), and the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway. Furthermore, we will discuss the hypothesis that periodontal pathogens may represent the unifying mechanism elucidating the intricate interconnection between periodontitis and HIV-1 latency. This article presents a detailed and comprehensive overview of the relationship underlying periodontitis and HIV-1 latency in terms of molecular mechanisms, which may provide novel theoretical insight into the pathogenesis of periodontitis and HIV-1 latency and reveal suitable therapeutic targets for the two diseases.

HIV latency-reversing activity of latex from Euphorbia umbellata (Pax) Bruyns and three diterpenes isolated from this species

Two unusual phorbol esters, namely 20-deoxyphorbol-3,4,12-triacetate-13-phenylacetate (1) and phorbol-3,4,12,13-tetraacetate-20-phenylacetate (2) plus ingol-3,8,12-triacetate-7-phenylacetate (3) were isolated from the latex of Euphorbia umbellata and identified by HRESIMS and 2D NMR. Compound 1 is herein described for the first time. Assignment of the phenylacetyl group at C-7 in compound 3 was suggested by the HMBC and NOESY spectra obtained in pyridine-d5. In addition to the latex and its distinct terpenoid fractions, the isolated compounds were tested as latent reversal agents against HIV-1-infected J-Lat cells, with reference to phorbol-12-myristate-13-acetate and ingenol-B. Compound 2 reverted 75-80% the viral latency on the GFP-positive cells, resulting EC50 3.70 μg/mL (SI 6.7), while 1 induced 34-40% reactivation at the same concentration range (4-20 µg/mL). The ingol derivative 3 was ineffective. Phorbol esters were confirmed as effective constituents in the latex since the fraction containing them was 2.4-fold more active than the lyophilised latex at the lowest concentration assayed.

Bioactive Compounds from Euphorbia usambarica Pax. with HIV-1 Latency Reversal Activity

Euphorbia usambarica is a traditional medicine used for gynecologic, endocrine, and urogenital illnesses in East Africa; however, its constituents and bioactivities have not been investigated. A variety of compounds isolated from Euphorbia species have been shown to have activity against latent HIV-1, the major source of HIV-1 persistence despite antiretroviral therapy. We performed bioactivity-guided isolation to identify 15 new diterpenoids (1–9, 14–17, 19, and 20) along with 16 known compounds from E. usambarica with HIV-1 latency reversal activity. Euphordraculoate C (1) exhibits a rare 6/6/3-fused ring system with a 2-methyl-2-cyclopentenone moiety. Usambariphanes A (2) and B (3) display an unusual lactone ring constructed between C-17 and C-2 in the jatrophane structure. 4β-Crotignoid K (14) revealed a 250-fold improvement in latency reversal activity compared to crotignoid K (13), identifying that configuration at the C-4 of tigliane diterpenoids is critical to HIV-1 latency reversal activity. The primary mechanism of the active diterpenoids 12–14 and 21 for the HIV-1 latency reversal activity was activation of PKC, while lignans 26 and 27 that did not increase CD69 expression, suggesting a non-PKC mechanism. Accordingly, natural constituents from E. usambarica have the potential to contribute to the development of HIV-1 eradication strategies.

Phorbol Esters from the Latex of Euphorbia umbellata: Bioguided Isolation of Highly Potent HIV-1 Latency Interrupters in Virus Reservoir Cells

Three known compounds, 20-deoxyphorbol-5β-hydroxy-12-tiglate-13-isobutyrate (1), 20-deoxyphorbol-5β-hydroxy-12-tiglate-13-phenylacetate (2), and 4-deoxy-4β-phorbol-12-tiglate-13-phenylacetate (3), were reisolated from the latex of Euphorbia umbellata through a bioguided fractionation process to target HIV-1 latency reactivation. The in vitro bioassay using infected T-cell lymphoblasts (J-Lat 10.6), complemented with surface CD4 receptor downregulation assessment, led to isolation of the compounds as a highly active ternary mixture. Effective purification of the individual compounds was achieved by first subjecting a phorbol-enriched fraction (previously prepared from crude latex) to MPLC, followed by semipreparative HPLC and characterization by 1D and 2D NMR spectroscopy and (+)-HRESIMS. Compared with a positive control, the isolated compounds were effective in reactivating 68-75% of the virus latency in the range of 9.7-0.097 μM for compound 1, 8.85-0.088 μM for compound 2, and 9.1-0.091 μM for compound 3, with the latter maintaining steady effectiveness down to a 10^-5 dilution. Accordingly, compound 3 may serve as a promising lead compound for the development of anti-HIV drugs based on latency reactivation therapy.

Enriched Terpenes Fractions of the Latex of Euphorbia umbellata Promote Apoptosis in Leukemic Cells

The current study was carried out by a bioguided fractionation of a hexane extract of the latex of Euphorbia umbellata against leukemic cells. Samples were analyzed by NMR, GC/MS, triterpenes quantification, and MTT reduction assay. Morphological, cell cycle, mitochondrial membrane potential and caspases 3/7 analyses were performed for the dichloromethane and ethanol fractions, and selectivity index for the dichloromethane fraction. NMR analysis presented characteristic signals of terpenes and steroids, data were confirmed by the quantification of triterpenes and GC/MS analysis. MTT reduction assay demonstrated that HL-60 was the most sensitive cell lineage against dichloromethane and ethanol fractions. Compounds of these matrices caused morphological changes compatible with apoptosis induction, altered cell cycle, increment of depolarized population cells and activation of caspases 3/7. Selectivity indices were higher than 22.44. Bioguided-fractionation study showed that samples of the latex of E. umbellata raised the activity of the phytocomplex against leukemic cells, and the cytotoxicity can be associated with an apoptosis pathway.

Antiretroviral treatment, government policy and economy of HIV/AIDS in Brazil: is it time for HIV cure in the country?

Brazil is a low-and-middle income country (LMIC) that, despite having a large population and continental dimensions, has been able to successfully fight HIV/AIDS through a number of governmental and societal measures. These included an early response to the epidemic, the development of a universal and free public health system, incisive discussions with pharmaceutical companies to reduce antiretroviral (ARV) drug prices, investments towards the development of generic drugs and compulsory licensing of ARVs. Through such measures, Brazil is among the leading LMIC towards achieving the 90-90-90 UNAIDS goals in the years to come. In this review, we analyze Brazil’s progress throughout the HIV/AIDS epidemic to achieve state-of-the-art ARV treatment and to reduce AIDS mortality in the country. The top-quality HIV/AIDS research in Brazil towards HIV prophylactic and functional cure, the next step towards the economic sustainability of the battle against HIV, is also discussed.

Euphorbia-Derived Natural Products with Potential for Use in Health Maintenance

Euphorbia genus (Euphorbiaceae family), which is the third largest genus of angiosperm plants comprising ca. 2000 recognized species, is used all over the world in traditional medicine, especially in the traditional Chinese medicine. Members of this taxa are promptly recognizable by their specialized inflorescences and latex. In this review, an overview of Euphorbia-derived natural products such as essential oils, extracts, and pure compounds, active in a broad range of biological activities, and with potential usages in health maintenance, is described. The chemical composition of essential oils from Euphorbia species revealed the presence of more than 80 phytochemicals, mainly oxygenated sesquiterpenes and sesquiterpenes hydrocarbons, while Euphorbia extracts contain secondary metabolites such as sesquiterpenes, diterpenes, sterols, flavonoids, and other polyphenols. The extracts and secondary metabolites from Euphorbia plants may act as active principles of medicines for the treatment of many human ailments, mainly inflammation, cancer, and microbial infections. Besides, Euphorbia-derived products have great potential as a source of bioactive extracts and pure compounds, which can be used to promote longevity with more health.

Dual effects of the novel ingenol derivatives on the acute and latent HIV-1 infections

The latent reservoir of HIV-1 in resting memory CD4⁺ T cells serves as a major barrier to curing HIV-1 infection. Reactivation of latent HIV-1 is proposed as a promising strategy for the clearance of the viral reservoirs. Because of the limitations of current latency reversal agents (LRAs), identification of new LRAs is urgently required. Here, we analyzed Euphorbia kansui extracts and obtained three ingenol derivative compounds named EK-1A, EK-5A and EK-15A. We found that ingenol derivatives can effectively reactivate latent HIV-1 at very low (nanomolar) concentrations in HIV latency model in vitro. Furthermore, ingenol derivatives exhibited synergy with other LRAs in reactivating latent HIV-1. We verified that EK-15A can promote latent HIV-1 reactivation in the ex vivo resting CD4⁺ T cells isolated from the peripheral blood of HIV-infected individuals on suppressive antiretroviral therapy. In addition, ingenol derivatives down-regulated the expression of cell surface HIV co-receptors CCR5 and CXCR4, therefore potentially preventing new infection of HIV-1. Our results indicated that the ingenol derivatives extracted from Euphorbia kansui have dual functions: reactivation of latent HIV-1 and inhibition of HIV-1 infection.