A novel dual-luciferase assay for anti-HIV drug screening based on the CCR5/CXCR4 promoters

Andrographolide suppresses SARS-CoV-2 infection by downregulating ACE2 expression: A mechanistic study

Angiotensin-converting enzyme 2 (ACE2) is the receptor that enables SARS-CoV-2 to invade host cells. Previous studies have reported that reducing ACE2 expression may have an anti-SARS-CoV-2 effect. In this study, we constructed a pGL4.10-F2-ACE2 vector with double luciferase genes (firefly and Renilla luciferase) under the control of the ACE2 promoter and used it to screen compounds from Chinese traditional medicinal herbs (CTMHs) that can inhibit ACE2 transcription in human cells. We transfected HEK293T cells with pGL4.10-F2-ACE2 and treated them with CTMH compounds and then measured fluorescence to evaluate the indirect inhibition of ACE2 transcription. Out of 37 compounds tested, andrographolide demonstrated a dose-dependent inhibition of ACE2 transcription. We further confirmed by RT-qPCR and Western blot assays that andrographolide also reduced ACE2 expression in BEAS-2B cells in a dose-dependent manner. Moreover, pseudovirus infection assays in BEAS-2B cells demonstrated that andrographolide can inhibit SARS-CoV-2 infection in a dose-dependent manner. These results suggest that andrographolide has potential anti-SARS-CoV-2 activity and could be a candidate drug for COVID-19 prevention and treatment.

Curcuma Longa Induces the Transcription Factor FOXP3 to Downregulate Human Chemokine CCR5 Expression and Inhibit HIV-1 Infection

HIV mutations occur frequently despite the substantial success of combination antiretroviral therapy, which significantly impairs HIV progression. Failure to develop specific vaccines, the occurrence of drug-resistant strains, and the high incidence of adverse effects due to combination antiviral therapy regimens call for novel and safer antivirals. Natural products are an important source of new anti-infective agents. For instance, curcumin inhibits HIV and inflammation in cell culture assays. Curcumin, the principal constituent of the dried rhizomes of Curcuma longa L. (turmeric), is known as a strong anti-oxidant and anti-inflammatory agent with different pharmacological effects. This work aims to assess curcumin's inhibitory effects on HIV in vitro and to explore the underpinning mechanism, focusing on CCR5 and the transcription factor forkhead box protein P3 (FOXP3). First, curcumin and the RT inhibitor zidovudine (AZT) were evaluated for their inhibitory properties. HIV-1 pseudovirus infectivity was determined by green fluorescence and luciferase activity measurements in HEK293T cells. AZT was used as a positive control that inhibited HIV-1 pseudoviruses dose-dependently, with IC50 values in the nanomolar range. Then, a molecular docking analysis was carried out to assess the binding affinities of curcumin for CCR5 and HIV-1 RNase H/RT. The anti-HIV activity assay showed that curcumin inhibited HIV-1 infection, and the molecular docking analysis revealed equilibrium dissociation constants of [Formula: see text]9.8[Formula: see text]kcal/mol and [Formula: see text]9.3[Formula: see text]kcal/mol between curcumin and CCR5 and HIV-1 RNase H/RT, respectively. To examine curcumin's anti-HIV effect and its mechanism in vitro, cell cytotoxicity, transcriptome sequencing, and CCR5 and FOXP3 amounts were assessed at different concentrations of curcumin. In addition, human CCR5 promoter deletion constructs and the FOXP3 expression plasmid pRP-FOXP3 (with an EGFP tag) were generated. Whether FOXP3 DNA binding to the CCR5 promoter was blunted by curcumin was examined using transfection assays employing truncated CCR5 gene promoter constructs, a luciferase reporter assay, and a chromatin immunoprecipitation (ChIP) assay. Furthermore, micromolar concentrations of curcumin inactivated the nuclear transcription factor FOXP3, which resulted in decreased expression of CCR5 in Jurkat cells. Moreover, curcumin inhibited PI3K-AKT activation and its downstream target FOXP3. These findings provide mechanistic evidence encouraging further assessment of curcumin as a dietary agent used to reduce the virulence of CCR5-tropic HIV-1. Curcumin-mediated FOXP3 degradation was also reflected in its functions, namely, CCR5 promoter transactivation and HIV-1 virion production. Furthermore, curcumin inhibition of CCR5 and HIV-1 might constitute a potential therapeutic strategy for reducing HIV progression.

The Importance of Traditional Chinese Medicine in the Intervention and Treatment of HIV while Considering its Safety and Efficacy

Natural products have been considered a potential resource for the development of novel therapeutic agents, since time immemorial. It is an opportunity to discover cost-effective and safe drugs at the earliest, with the goal to hit specific targets in the HIV life cycle. Natural products with inhibitory activity against human immunodeficiency virus are terpenes, coumarins, flavonoids, curcumin, proteins, such as lectins, laccases, bromotyrosines, and ribosome-inactivating proteins. Terpenes inhibit virus fusion, lectins and flavonoids have an inhibitory impact on viral binding, curcumin and flavonoids inhibit viral DNA integration. The most important medicinal plants which have been used in traditional Chinese medicinal sciences with anti-HIV properties are Convallaria majalis, Digitalis lanata, Cassia fistula, Croton macrostachyus, Dodonaea angustifolia, Ganoderma lucidum, Trametes versicolor, Coriolus versicolor, Cordyceps sinensis, Gardenia jasminoides, Morus alba, Scutellaria baicalensis, Ophiopogon japonicus, Platycodon grandiflorus, Fritillaria thunbergii, Anemarrhena asphodeloides, Trichosanthes kirilowii, Citrus reticulata, Glycyrrhiza uralensis, Rheum officinale, Poria cocos, Rheum palmatum, Astragalus membranaceus, Morinda citrifolia, Potentilla kleiniana, Artemisia capillaris, Sargassum fusiforme, Piperis longi fructus, Stellera chamaejasme, Curcumae rhizoma, Dalbergia odorifera lignum, Arisaematis Rhizoma preparatum, and Phellodendron amurense. The information provided is gathered from randomized control experiments, review articles, and analytical studies and observations, which are obtained from different literature sources, such as Scopus, Google Scholar, PubMed, and Science Direct from July 2000 to August 2023. The aim of this review article is to survey and introduce important medicinal plants and herbs that have been used for the treatment of HIV, especially the medicinal plants that are common in traditional Chinese medicine, as research to date is limited, and more evidence is required to confirm TCM,s efficacy.

Coelenterazine-Dependent Luciferases as a Powerful Analytical Tool for Research and Biomedical Applications

: The functioning of bioluminescent systems in most of the known marine organisms is based on the oxidation reaction of the same substrate-coelenterazine (CTZ), catalyzed by luciferase. Despite the diversity in structures and the functioning mechanisms, these enzymes can be united into a common group called CTZ-dependent luciferases. Among these, there are two sharply different types of the system organization-Ca2+-regulated photoproteins and luciferases themselves that function in accordance with the classical enzyme-substrate kinetics. Along with deep and comprehensive fundamental research on these systems, approaches and methods of their practical use as highly sensitive reporters in analytics have been developed. The research aiming at the creation of artificial luciferases and synthetic CTZ analogues with new unique properties has led to the development of new experimental analytical methods based on them. The commercial availability of many ready-to-use assay systems based on CTZ-dependent luciferases is also important when choosing them by first-time-users. The development of analytical methods based on these bioluminescent systems is currently booming. The bioluminescent systems under consideration were successfully applied in various biological research areas, which confirms them to be a powerful analytical tool. In this review, we consider the main directions, results, and achievements in research involving these luciferases.