To investigate the effect of 1800 MHz electromagnetic radiation (EMR) on apoptosis, we exposed NIH/3T3 cells at 1800 MHz with a specific absorption rate (SAR) of 2 W/kg intermittently for 12, 24, 36, and 48 h. After exposure, Cell Counting Kit-8 (CCK-8) and flow cytometry were used to detect cell viability and apoptosis; the expression of p53, a molecule with the key role in apoptosis, was measured by real-time qPCR, western blot, and immunofluorescence; and images of the structure of the mitochondria, directly reflecting apoptosis, were captured by electron microscopy. The results showed that the viability of cells in the 12, 36, and 48 h exposure groups significantly decreased compared with the sham groups; after 48 h of exposure, the percentage of late apoptotic cells in the exposure group was significantly higher. Real-time qPCR results showed that p53 mRNA in the 48 h exposure group was 1.4-fold of that in the sham group; significant differences of p53 protein fluorescence expression were observed between the exposure groups and the sham groups after 24 h and 48 h. The mitochondrial swelling and vesicular morphology were found in the electron microscopy images after 48 h exposure. These findings demonstrated 1800 MHz, SAR 2 W/kg EMR for 48 h may cause apoptosis in NIH/3T3 cells and that this apoptosis might be attributed to mitochondrial damage and upregulation of p53 expression.

Here, we report the anti-human immunodeficiency virus (HIV) potency and underlying mechanisms of a Keggin polyoxometalate (PT-1, K₆HPTi₂W₁₀O₄₀). Our findings showed that PT-1 exhibited highly potent effects against a diverse group of HIV type 1 (HIV-1) strains and displayed low cytotoxicity and genotoxicity. The time-addition assay revealed that PT-1 acted at an early stage of infection, and these findings were supported by the observation that PT-1 had more potency against Env-pseudotyped virus than vesicular stomatitis virus glycoprotein (VSVG) pseudotyped virus. Surface plasmon resonance binding assays and flow cytometry analysis showed that PT-1 blocked the gp120 binding site in the CD4 receptor. Moreover, PT-1 bound directly to gp41 NHR (N36 peptide), thereby interrupting the core bundle formation of gp41. In conclusion, our data suggested that PT-1 may be developed as a new anti-HIV-1 agent through its effects on entry inhibition.

Bone marrow stromal cell antigen 2 (BST-2), also known as CD317 or tetherin, has been identified as a host restriction factor that suppresses the release of enveloped viruses from host cells by physically tethering viral particles to the cell surface; however, this host defense can be subverted by multiple viruses. For example, human immunodeficiency virus (HIV)-1 encodes a specific accessory protein, viral protein U (Vpu), to counteract BST-2 by binding to it and directing its lysosomal degradation. Thus, blocking the interaction between Vpu and BST-2 will provide a promising strategy for anti-HIV therapy. Here, we report a NanoLuc Binary Technology (NanoBiT)-based high-throughput screening assay to detect inhibitors that disrupt the Vpu-BST-2 interaction. Out of more than 1000 compounds screened, four inhibitors were identified with strong activity at nontoxic concentrations. In subsequent cell-based BST-2 degradation assays, inhibitor Y-39983 HCl restored the cell-surface and total cellular level of BST-2 in the presence of Vpu. Furthermore, the Vpu-mediated enhancement of pesudotyped viral particle production was inhibited by Y-39983 HCl. Our findings indicate that our newly developed assay can be used for the discovery of potential antiviral molecules with novel mechanisms of action.

The demethylation potential of environmental pollutants is possibly an innate part of their comprehensive health risk. This paper develops a novel method called TDQ to quantify the demethylation epigenetic toxicity, termed the 5-AZA-CdR demethylation toxic equivalency, of aquatic samples from the heavily polluted Bohai Bay using Hep G2 cell lines transiently transfected with the pEGFP-C3 plasmid containing a methylated promoter of the EGFP reporter gene inserted artificially in vitro. If the aquatic sample extract has strong total demethylation potential to the promoter, its methylation level will decrease, and increased green fluorescence will be observed under microscopy after TDQ co-incubation. The 5-AZA-CdR was selected as a representative demethylation agent to validate the principle of the TDQ method on three levels: significant dose–response relationships between the concentration of 5-AZA-CdR and the methylation level of promoters, mRNA expression level of the EGFP gene, and the fluorescence intensity of EGFP proteins. Twenty extracts from aquatic samples are successfully quantified with the TDQ test. Eight of them return meaningful results ranging from 0.00004 to 0.20053 μM 5-AZA-CdR toxicity equivalents. The TDQ method is a reliable and rapid assay for the quantification of the DNA demethylation potential of aquatic sample extracts, which may shed light on the safety evaluation of food material.

Papain-like protease (PLpro), a crucial functional domain of the SARS-CoV-2 non-structural protein 3 (nsp3), plays a dual role in both hydrolyzing viral polyprotein precursors and modulating host immune responses. These critical functions position PLpro as a key target in the ongoing development of antiviral therapies for SARS-CoV-2. This review analyzes more than 100 PLpro-ligand co-crystal structures and summarizes the major binding modes between these ligands and PLpro. Most of these ligands bind to sites analogous to those targeted by the classical non-covalent inhibitor GRL0617, primarily involving the P3 and P4 subsites and the BL2 loop. Based on these structural insights, optimized inhibitors have expanded targeting beyond the canonical binding site to auxiliary regions such as the BL2 groove and the Val70 site, and in some cases toward the catalytic Cys111 buried within a narrow pocket. Certain ligands identified through various screening approaches bind to non-canonical or allosteric regions, such as the S1 and S2 sites or the zinc-finger domain, engaging PLpro through distinct interaction modes and thereby offering additional opportunities for PLpro inhibitor design. The review also discusses potential strategies for future PLpro inhibitor development informed by recent structural advances. Taken together, these structural and functional insights support ongoing efforts in the structure-guided design and optimization of PLpro inhibitors.