Role of aryl hydrocarbon receptors in infection and inflammation.

The aryl hydrocarbon receptor (AhR) is a transcription factor that is activated by various ligands, including pollutants, microorganisms, and metabolic substances. It is expressed extensively in pulmonary and intestinal epithelial cells, where it contributes to barrier defense. The expression of AhR is pivotal in regulating the inflammatory response to microorganisms. However, dysregulated AhR expression can result in endocrine disorders, leading to immunotoxicity and potentially promoting the development of carcinoma. This review focuses on the crucial role of the AhR in facilitating and limiting the proliferation of pathogens, specifically in relation to the host cell type and the species of etiological agents involved in microbial pathogen infections. The activation of AhR is enhanced through the IDO1-AhR-IDO1 positive feedback loop, which is manipulated by viruses. AhR primarily promotes the infection of SARS-CoV-2 by inducing the expression of angiotensin-converting enzyme 2 (ACE2) and the secretion of pro-inflammatory cytokines. AhR also plays a significant role in regulating various types of T-cells, including CD4+ T cells and CD8+ T cells, in the context of pulmonary infections. The AhR pathway plays a crucial role in regulating immune responses within the respiratory and intestinal barriers when they are invaded by viruses, bacteria, parasites, and fungi. Additionally, we propose that targeting the agonist and antagonist of AhR signaling pathways could serve as a promising therapeutic approach for combating pathogen infections, especially in light of the growing prevalence of drug resistance to multiple antibiotics.

Nickel doping of ferrous disulfide nanocubes exhibits enhanced oxidase-like activity for In vitro detection of total antioxidant capacity.

The development of nanomaterials that mimic oxidase-like activities has recently attracted an increasing amount of attention. Obtaining highly active and cost-effective oxidase mimics has posed a significant challenge in this area of research. In this study, we successfully synthesized nickel-doped ferrous disulfide nanocubes (Ni-FeS2) via a facile one-step method. Characterization by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that Ni was predominantly distributed within the surface layer of the Ni-FeS2 nanocubes. The incorporation of nickel in density functional theory (DFT) calculations effectively reduced the d-band center of Fe, resulting in weakened adsorption to intermediates and thereby enhancing its catalytic efficiency. Moreover, we developed a novel approach based on Ni-FeS2 (the Ni-FeS2 method) for detecting reducing substances, which exhibited good sensitivity toward ascorbic acid (AA), glutathione (GSH), and cysteine (Cys). Remarkably, the established Ni-FeS2 method was successfully employed for in vitro assessment of total antioxidant capacity (TAC) in cellular and organ samples, thereby enabling discrimination between normal, senescent, and malignant cells as well as distinguishing among healthy liver tissue, cancerous liver tissue, and metastatic organs.

Design, synthesis and bioactivity evaluation of favorable evodiamine derivative scaffold for developing cancer therapy.

Natural product evodiamine is one of the most privileged scaffolds in drug discovery and is suitable for derivatization, which can be conducted quickly for structure optimization and structure-activity relationship research. In this work, a comprehensive SAR study on evodiamine scaffold with N14-3'-fluorophenyl substituted was completed, and compounds with high anti-tumor activity and good inhibitory effect on Top1 and Top2 were screened out. Tested evodiamine derivatives exhibited excellent broad-spectrum anti-tumor activity. Among them, compound 8b revealed 55.15% and 55.50% inhibition for Top1 and Top2 at 25 µM, as well as 0.16 and 0.13 µM IC50 value for MGC-803 and SGC-7901 cells, respectively; compound 9a revealed 70.50% and 71.81% inhibition for Top1 and Top2 at 25 µM, as well as 0.22 and 0.27 µM IC50 value for MGC-803 and SGC-7901 cells, respectively. The further biological evaluation showed that they could functionally induce apoptosis, significantly arrest the cell cycle at the G2/M phase, and markedly inhibit cell proliferation, migration and invasion. In addition, compound 9a performed a tumor inhibitory rate of 36.35% and showed no apparent toxicity in vivo. Overall, these optimized protocols will advance the progression of cancer chemotherapy and can be used to expand the options for screening therapeutic cancer drugs.

Curcumin suppressed proliferation and migration of human retinoblastoma cells through modulating NF-κB pathway.

PURPOSE: To study the effect of curcumin on proliferation and invasion of the human retinoblastoma cells and its potential mechanism. METHODS: A cell line of retinoblastoma (WERI-Rb-1) was treated with various concentrations of curcumin (0-40 µM). Cell number was counted with CCK8 kit, and cell migration was assessed using the Transwell assay. Immunoblotting was performed to detect the proteins of metalloproteinase-2 (MMP-2), MMP-9 and vascular endothelial growth factor (VEGF) as well as nuclear translocation of nuclear factor-κB (NF-κB, p65). RESULTS: Proliferation and migration of WERI-Rb-1 cells were significantly inhibited by curcumin in a concentration-dependent manner (0-40 µM). Protein expressions of MMP-2, MMP-9 and VEGF in the WERI-Rb-1 cells were also significantly inhibited by curcumin in a concentration-dependent manner (0-40 µM). Furthermore, nuclear translocation of NF-κB (p65) was significantly inhibited by curcumin in time-dependent manner (6-24 h). CONCLUSION: Curcumin inhibited proliferation and migration of WERI-Rb-1 cells, a cell line of human retinoblastoma, which might be through modulating NF-κB and its downstream proteins including VEGF, MMP-2, and MMP-9.

[Preparation and identification of the polyclonal antibody against ATRX-C2193-2492].

Objective To prepare the polyclonal antibody against human alpha thalassemia/mental retardation syndrome X-linked (ATRX) C-terminal and study the distribution and expression of ATRX protein in human cervical cancer tissues. Methods The antiserum was obtained from the BALB/c mice immunized with 6His-ATRX-C2193-2492 protein and then purified by the saturated ammonium sulfate precipitation and affinity chromatography. The titer of anti-ATRX polyclonal antibody was determined by ELISA. Its specificity was identified by SDS-PAGE analysis and Western blotting. The expression and location of ATRX in human cervical tissues were analyzed by immunohistochemistry. Results The titer of the polyclonal antibody against 6His-ATRX-C2193-2492 protein was about 1:12 800. The antibody could recognize 6His-ATRX-C2193-2492 protein specifically. With the polyclonal antibody, the target protein was found mainly in the nucleus of para-carcinoma tissues, and it was also expressed in the nucleus of cervical cancer tissue cells, but the expression in the latter was obviously lower. Conclusion The polyclonal antibody against 6His-ATRX-C2193-2492 protein has been produced successfully and used to detect ATRX protein in human cervical cancer tissues.

[Mycoplasma genitalium-derived lipid-associated membrane proteins negatively regulate cytokine secretion by inducing HO-1 expression in placental trophoblast cells].

OBJECTIVE: To observe the expression of heme oxygenase-1 (HO-1) in regulation of cytokines response induced by Mycoplasma genitalium-derived lipid-associated membrane proteins (LAMPs) in placental trophoblast cells. METHODS: Placental trophoblast cells were cultured in vitro and stimulated by 0.5-5 µg/mL LAMPs for 4 to 12 hours. Expression of HO-1 mRNA and protein, and nuclear translocation of nuclear factor erythroid-2 related factor 2 (Nrf2) were detected by real-time quantitative PCR and Western blotting, respectively. The intracellular formation of reactive oxygen species (ROS) was detected by the fluorescent probe H2DCFDA. N-acetyl-cysteine (NAC) and nuclear factor erythroid-2 related factor 2 (Nrf2) siRNA were respectively used to analyze the roles of ROS and Nrf2 in mediating HO-1 expression. Finally, placental trophoblast cells were transfected with HO-1 siRNA, or preincubated by the HO-1 agonist cobalt protoporphyrin (CoPP) or its inhibitor zinc protoporphyrin (ZnPP), and LAMPs-induced secretion of TNF-α and IL-1ß were detected by ELISA. RESULTS: M. genitalium LAMPs induced the expression of HO-1 mRNA and protein, the accumulation of ROS and the nuclear translocation of Nrf2 in placental trophoblast cells. NAC treatment inhibited LAMPs-induced HO-1 expression and Nrf2 nuclear translocation, and the transfection of Nrf2 siRNA significantly abrogated HO-1 expression. Furthermore, HO-1 siRNA and ZnPP treatment increased LAMPs-induced TNF-α and IL-1ß secretion, while the HO-1 agonist CoPP treatment further decreased their production. CONCLUSION: M. genitalium LAMPs could induce placental trophoblast cells to express HO-1 through ROS/Nrf2 pathways. Up-regulation of HO-1 negatively regulates excessive production of cytokines.

[Mycoplasma genitalium lipid-associated membrane proteins induce endocervical epithelial cells to express ß-defensin-2].

OBJECTIVE: To observe the expression of human ß-defensin-2 (hBD-2) induced by Mycoplasma genitalium-derived lipid-associated membrane proteins (LAMPs) and its potential mechanism. METHODS: Human endocervical epithelial End1/E6E7 cells were cultured in vitro and stimulated by different concentrations of LAMPs for 48 hours, and the expressions of hBD-2 mRNA and protein were detected by real-time RT-PCR and Western blotting, respectively. Toll-like receptor 2 (TLR2) and TLR6 neutralizing antibodies for End1/E6E7 cell cultivation, and dominant negative plasmids for cell transfection were used to analyze the roles of TLR2, TLR6 and MyD88 in mediating hBD-2 expression. Nuclear translocation of the nuclear factor κB (NF-κB) p65 subunit, and its DNA-binding activity were detected by Western blotting and electrophoretic mobility shift assay (EMSA), respectively. Pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-κB, was used to investigate the effect of NF-κB on hBD-2 expression. RESULTS: Mycoplasma genitalium-derived LAMPs induced the expressions of hBD-2 mRNA and protein in End1/E6E7 cells. The expressions could be abrogated by TLR2 and TLR6 neutralizing antibodies, or their dominant negative plasmids. In addition, dominant negative plasmids of MyD88 significantly decreased LAMPs-induced hBD-2 expression. Western blotting showed that p65 was translocated to the nucleus, and the DNA binding activity of NF-κB was enhanced after LAMPs treatment. Furthermore, PDTC treatment decreased LAMPs- induced hBD-2 expression. CONCLUSION: Mycoplasma genitalium-derived LAMPs can induce End1/E6E7 cells to express hBD-2, which may be involved in the TLR2, TLR6/Myd88/NF-κB pathways.

Both plant and animal LEA proteins act as kinetic stabilisers of polyglutamine-dependent protein aggregation.

LEA (late embryogenesis abundant) proteins are intrinsically disordered proteins that contribute to stress tolerance in plants and invertebrates. Here we show that, when both plant and animal LEA proteins are co-expressed in mammalian cells with self-aggregating polyglutamine (polyQ) proteins, they reduce aggregation in a time-dependent fashion, showing more protection at early time points. A similar effect was also observed in vitro, where recombinant LEA proteins were able to slow the rate of polyQ aggregation, but not abolish it altogether. Thus, LEA proteins act as kinetic stabilisers of aggregating proteins, a novel function in protein homeostasis consistent with a proposed role as molecular shields.