Celastrol induced the autophagy of spermatogonia cells contributed to tripterygium glycosides-related testicular injury.

Tripterygium glycosides (TG) is extracted from the roots of Chinese herbal medicine named Tripterygium wilfordii Hook F (TwHF). TG tablets are the representative TwHF-based agents with anti-inflammatory and immunomodulatory activities for treating rheumatoid arthritis. Although the curative effect of TG is remarkable, the clinical application is limited by a variety of organ toxicity. One of the most serious side-effects induced by TG is damage of the male reproductive system and the toxic mechanism is still not fully elucidated. TG-induced testicular injury was observed in male mice by treated with different concentrations of TG. The results showed that TG induced a significant decrease in testicular index. Pathological observation showed that spermatogenic cells were obviously shed, arranged loosely, and the spermatogenic epithelium was thin compared with control mice. In addition, the toxic effect of TG on mouse spermatogonia GC-1 cells was investigated. The results displayed that TG induced significant cytotoxicity in mouse GC-1 cells. To explore the potential toxic components that triggered testicular injury, the effects of 8 main components of TG on the viability of GC-1 cells were detected. The results showed that celastrol was the most toxic component of TG to GC-1 cells. Western blot analysis showed that LC3-II and the ratio of LC3-II/LC3-I were significantly increased and the expression level of p62 were decreased in both TG and celastrol treated cells, which indicated the significant activation of autophagy in spermatogonia cells. Therefore, autophagy plays an important role in the testicular injury induced by TG, and inhibition of autophagy is expected to reduce the testicular toxicity of TG.

Recent advances in the pharmacological applications and liver toxicity of triptolide.

Triptolide is a predominant active component of Triptergium wilfordii Hook. F, which has been used for the treatment of cancers and autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus and diabetic nephropathy. Therefore, triptolide and its derivates are considered to have promising prospects for development into drugs. However, the clinical application of triptolide is limited due to various organ toxicities, especially liver toxicity. The potential mechanism of triptolide-induced hepatotoxicity has attracted increasing attention. Over the past five years, studies have revealed that triptolide-induced liver toxicity is involved in metabolic imbalance, oxidative stress, inflammations, autophagy, apoptosis, and the regulation of cytochrome P450 (CYP450) enzymes, gut microbiota and immune cells. In this review, we summarize the pharmacological applications and hepatotoxicity mechanism of triptolide, which will provide solid theoretical evidence for further research of triptolide.

SARS-CoV-2 spike host cell surface exposure promoted by a COPI sorting inhibitor.

Via an insufficient coat protein complex I (COPI) retrieval signal, the majority of SARS-CoV-2 spike (S) is resident in host early secretory organelles and a tiny amount is leaked out in cell surface. Only surface-exposed S can be recognized by B cell receptor (BCR) or anti-S therapeutic monoclonal antibodies (mAbs) that is the trigger step for B cell activation after S mRNA vaccination or infected cell clearance by S mAbs. Now, a drug strategy to promote S host surface exposure is absent. Here, we first combined structural and biochemical analysis to characterize S COPI sorting signals. A potent S COPI sorting inhibitor was then invented, evidently capable of promoting S surface exposure and facilitating infected cell clearance by S antibody-dependent cellular cytotoxicity (ADCC). Importantly, with the inhibitor as a probe, we revealed Omicron BA.1 S is less cell surface exposed than prototypes because of a constellation of S folding mutations, possibly corresponding to its ER chaperone association. Our findings not only suggest COPI is a druggable target against COVID-19, but also highlight SARS-CoV-2 evolution mechanism driven by S folding and trafficking mutations.

Bifunctional phase-transfer catalysts for synthesis of 2-oxazolidinones from isocyanates and epoxides.

A series of bifunctional phase-transfer catalysts (PTCs) were synthesized to catalyze the [3 + 2] coupling reaction of isocyanates and epoxides to afford 2-oxazolidinones in good to high yields (up to 92% yield) using PhCl as a solvent at 100 °C within 12 h. These bifunctional PTCs were easily prepared from commercially available tertiary-primary diamines and isocyanates (or isothiocyanates, mono-squaramides, respectively) in two simple steps with good modularity and demonstrated high efficiency (2.5 mol% catalyst-loading). The synergistic interaction of the quaternary ammonium salt center and hydrogen-bond donor group in the catalyst with the substrate is crucial to this atom-economic reaction.

Selenium nanoparticles fabricated in laminarin polysaccharides solutions exert their cytotoxicities in HepG2 cells by inhibiting autophagy and promoting apoptosis.

Selenium nanoparticles (SeNPs) have been attracting increasing attention as potential cancer therapeutic agents. In the present study, laminarin polysaccharides (LP) decorated selenium nanoparticles (LP-SeNPs) with an average diameter of ca. 60 nm were synthesized. Transmission electron microscope (TEM), laser particle analyzer, UV-visible spectrometer and Energy dispersive X-ray (EDX) spectrometer were applied to characterize the prepared SeNPs. The cytotoxicity, apoptosis, and autophagy were examined using a series of cellular assays. The results revealed that LP-SeNPs exhibited cytotoxicity against HepG2 cells with IC50 value was 23.4 ±â€¯2.7 µM. After cells were treated with various concentrations of LP-SeNPs (10, 20 and 40 µM) for 24h, the total apoptosis rate increased to 17.4 ±â€¯1.6, 20.9 ±â€¯1.3 and 30.9 ±â€¯1.2%, respectively. Additionally, treatment of LP-SeNPs increased the expression of Bax and cleaved caspase-9 but decreased the level of Bcl-2. This suggested that LP-SeNPs induced mitochondria-mediated apoptosis. Further, exposure of cells to LP-SeNPs for 12 h induced the upregulation of LC3-II and p62. Treatment of chloroquine (CQ), the inhibitors of the autophagosome, resulted in further accumulation of p62 and LC3-II. These results demonstrated that LP-SeNPs induced the activation of early autophagy, but blocked the late phase of autophagy. Inhibition of late phase of autophagy resulted in the damaged organelles cannot be cleared and aggravating apoptosis. In conclusion, these results indicated that LP-SeNPs exerted its cytotoxicity in HepG2 cells by inhibiting autophagy and inducing apoptosis.

Liquid chromatography-tandem mass spectrometry to assess the pharmacokinetics and tissue distribution of withaferin A in rats.

Withaferin A (WA) is a bioactive ingredient in the medicinal Indian herb Withania somnifera (WS). In this study, we developed a rapid and accurate Liquid Chromatography-tandem Mass Spectrometry (LC-MS/MS) method to determine the concentration of WA in rat plasma and tissue following intravenous (i.v., 4.5 mg/kg) and oral (i.g, 0.5, 1.5 and 4.5 mg/kg) administration. WA was isolated on a Hypurity C18 (50 × 4.6 mm, 5 µm) column by isocratic elution at a flow rate of 0.5 mL/min using acetonitrile and water as the mobile phase (35:65, v/v). The retention time was 4 min. Ethyl acetate containing 5% ascorbic acid was used as the extraction solvent through simple liquid-liquid extraction (LLE). Withanolide A (WLD) was used as the internal standard (IS). Quantification was performed through multiple reaction monitoring (MRM) modes of m/z 471.1 → 281 for WA and m/z 488.1 → 263 for IS in the positive-ion mode. This revealed no significant effects of the WA concentration or administration route on the T1/2. The distribution of WA in the various tissues was in the order: stomach > heart > lung > kidney > small intestinal > spleen > following i.g administration (4.5 mg/kg). These data provide valuable insight into the clinical parameters of WA.

Highly Efficient Michael Reactions of Nitroolefins by Grinding Means.

AIM AND OBJECTIVE: The direct ß-functionalization of trans-ß-nitroolefins by Michael reaction is regarded as an efficient way to provide precursors for ß-functional amines. However, Michael additions by grinding means with solvent-free conditons are rarely reported. We have developed facile access to ß-functional nitroalkanes by grinding means under solvent-free conditions. MATERIALS AND METHODS: From commercially available materials including ethyl 2-nitroacetate, alkyl 2-cyanoacetates and malononitrile, the grinding reactions between these above-mentioned activated methylenecompounds and various trans-ß-nitroolefins were performed at room temperature and solvent-free conditions. RESULTS: A highly efficient direct Michael reaction of nitroolefins by simple grinding means has been developed. Various trans-nitrostyrenes were easily converted into corresponding ß-functional nitroalkanes in excellent yields within 5~10 min (up to 36 examples). CONCLUSION: Herein, we have developed a simple and efficient way to ß-functional nitroalkanes through Michael reactions by grinding means. The grinding Michael reaction is fast, clean and stable and these Michael adducts could be easily converted into the other amino compounds served as building blocks in organic synthesis.

Green synthesis of selenium nanoparticles with extract of hawthorn fruit induced HepG2 cells apoptosis.

CONTEXT: Selenium nanoparticles (SeNPs) have attracted worldwide attention due to their unique properties and potential bioactivities. Considering that hawthorn is both a traditional medicine and a common edible food, hawthorn fruit extract (HE) was chosen as a reductant to prepare SeNPs. OBJECTIVE: SeNPs were synthesized by using an aqueous HE as a reductant and stabilizer. The antitumor activities and potential mechanisms of SeNPs were explored by using a series of cellular assays. MATERIALS AND METHODS: The HE mediated SeNPs (HE-SeNPs) were examined using various characterisation methods. The cytotoxicity was measured against HepG2 cells after treated with 0, 5, 10 and 20 µg/mL of HE-SeNPs for 24 h. Annexin V-FITC/PI staining analysis was performed to observe the apoptosis of HepG2 cells. Additionally, mitochondrial membrane potential (MMP), intracellular reactive oxygen species (ROS) levels were evaluated. Finally, the protein expression levels of caspase-9 and Bcl-2 were identified by Western blot. RESULTS: The mono-dispersed and stable SeNPs were prepared with an average size of 113 nm. HE-SeNPs showed obvious antitumor activities towards HepG2 cells with an IC50 of 19.22 ± 5.3 µg/mL. Results from flow cytometry revealed that both early and total apoptosis rates increased after treating with HE-SeNPs. After cells were treated with various concentrations of HE-SeNPs (5, 10 and 20 µg/mL) for 24 h, the total rate increased to 7.3 ± 0.5, 9.7 ± 1.7 and 19.2 ± 1.6%, respectively. Meanwhile, treatment of HE-SeNPs up-regulated intracellular ROS levels and reduced the MMP. In addition, HE-SeNPs induced the up-regulation of caspase-9 and down-regulation of Bcl-2. DISCUSSION AND CONCLUSIONS: HE-SeNPs induced intracellular oxidative stress and mitochondrial dysfunction to initiate HepG2 cell apoptosis through the mitochondrial pathway. Therefore, HE-SeNPs may be a candidate for further evaluation as a chemotherapeutic agent for human liver cancer.

Protective effect of hydroxysafflor yellow A against acute kidney injury via the TLR4/NF-κB signaling pathway.

This study aimed to evaluate the protective effect of hydroxysafflor yellow A (HSYA) on ischemia/reperfusion (I/R)-induced acute kidney injury via the TLR4/NF-κB pathway, both in vitro and in vivo. Rats were subjected to removal of the right kidney and I/R injury to the left kidney. Rats subjected to renal I/R injury were treated with HSYA at 0.5 h prior to I/R injury. Renal function, histopathological analysis, and cells apoptosis were measured in vivo. In vitro, proximal renal tubular cells (HK-2) were subjected to hypoxia/reoxygenation (H/R). Apoptotic cell death and inflammatory cytokines, Toll-like receptor 4 (TLR4), and nuclear factor (NF)-κB expression were determined. Treatment of I/R rats with HSYA markedly reduced the levels of serum creatinine and blood urea nitrogen, attenuated renal cell apoptosis, alleviated changes in renal tissue morphology, and reduced IL-1ß, TNF-α, and caspase-3 release. In vitro, HSYA effectively decreased NF-κB p65 and inflammatory cytokines, such as IL-1ß, TNF-α, and IL-6. Thus, HSYA can protect renal function from I/R injury by ameliorating acute kidney injury and partly by promoting tubular cell survival via the TLR4/NF-κB pathway. These results suggest that HSYA can be used to prevent I/R-induced acute kidney injury.

Synthesis, characterization and antitumor properties of selenium nanoparticles coupling with ferulic acid.

Selenium nanoparticles (Se NPs) attract a lot of attention as potential cancer therapeutic agents. However, the antitumor activities of pure Se NPs are poor, and some modifiers are needed to enhance the activities. In the present study, we prepared Ferulic Acid (FA)-modified selenium nanoparticles in a facile synthetic approach. The obtained FA-Se NPs were characterized using transmission electron microscope (TEM), dynamic light scattering (DLS), ultraviolet-visible spectrophotometer (UV-VIS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Energy dispersive X-ray (EDX) spectroscopy. In vitro antitumor effects of FA, Se NPs and FA-Se NPs in HepG-2 cells were examined by methyl thiazolyl tetrazolium (MTT) assay. It showed that FA-Se NPs effectively inhibited the growth of HepG-2 cells with IC50 value of 11.57 ±â€¯3.6 µg/ml, while the value of Se NPs was >100 µg/ml. In addition, FA behaves no obvious antitumor effects at high concentrations up to 100 µg/ml. In order to investigate the antitumor mechanism of FA-Se NPs, fluorescence morphological examination and Annexin V-FITC/PI staining analysis were performed to observe the apoptosis of HepG-2 cells induced by FA-Se NPs. Meanwhile, mitochondrial membrane potential (MMP), intracellular reactive oxygen species (ROS) levels and caspase-3 and -9 activities were detected. The results revealed that FA-Se NPs induced intracellular ROS generation and MMP disruption by finally activating caspase-3/9 to trigger HepG-2 cells apoptosis through mitochondrial pathway. Further investigation on the interactions of FA-Se NPs with calf thymus DNA (ctDNA) indicated that the antitumor activities may be associated with the DNA-binding properties of FA-Se NPs.

Enantioselective amination of nitroolefins under base-free and water-rich conditions using chiral bifunctional phase-transfer catalysts.

The direct enantioselective amination of nitroolefins has been performed with l-tert-leucine-derived squaramide-scaffold bifunctional phase-transfer catalysts under base-free and water-rich conditions with low catalyst loading (0.5-1 mol%) to provide 2-aminonitroalkanes in good yields (up to 96%) and enantioselectivities (up to 93% ee).

Synthesis and cytotoxic activities of novel 4-methoxy-substituted and 5-methyl-substituted (3'S,4'S)-(-)-cis-khellactone derivatives that induce apoptosis via the intrinsic pathway.

This study deals with the design and synthesis of a series of novel 4-methoxy-substituted and 5-methyl-substituted (3'S,4'S)-(-)-cis-khellactones. The newly synthesized compounds were characterized by 1H nuclear magnetic resonance (NMR), 13C-NMR, mass spectrometry, and elemental analysis. All the derivatives were subjected to in vitro cytotoxicity screening against HEPG-2 (human liver carcinoma), SGC-7901 (human gastric carcinoma), and LS174T (human colon carcinoma), by using the MTT assay. The results revealed that several of the 4-methoxy-substituted compounds exhibited potent cytotoxicity. Among these, compound 12e showed the highest activity against cancer cells which 50% inhibitory concentration (IC50) values were in the range of 6.1-9.2 µM with low toxicity on normal human hepatocyte. Preliminary investigation of possible mechanisms of action of compound 12e against HEPG-2 cells indicated possible induction of apoptosis, as determined by morphological observations and Annexin V/propidium iodide (PI) double staining, in addition to apparent dissipation of mitochondrial membrane potential (MMP), as measured by 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethyl-imidacarbocyanine iodide (JC-1) staining in combination with the activation of caspase-9 and caspase-3 by Western blot analysis. Overall, the data suggest that compound 12e may be a promising potential anti-cancer agent that could act primarily by inducing apoptosis through the mitochondria-mediated intrinsic pathway in human hepatoma cells.