The reduction of nitrate to nitrite by the oral microbiota has been proposed to be important for oral health and results in nitric oxide formation that can improve cardiometabolic conditions. Studies of bacterial composition in subgingival plaque suggest that nitrate-reducing bacteria are associated with periodontal health, but the impact of periodontitis on nitrate-reducing capacity (NRC) and, therefore, nitric oxide availability has not been evaluated. The current study aimed to evaluate how periodontitis affects the NRC of the oral microbiota. First, 16S rRNA sequencing data from five different countries were analyzed, revealing that nitrate-reducing bacteria were significantly lower in subgingival plaque of periodontitis patients compared with healthy individuals (P < 0.05 in all five datasets with n = 20-82 samples per dataset). Secondly, subgingival plaque, saliva, and plasma samples were obtained from 42 periodontitis patients before and after periodontal treatment. The oral NRC was determined in vitro by incubating saliva with 8 mmol/L nitrate (a concentration found in saliva after nitrate-rich vegetable intake) and compared with the NRC of 15 healthy individuals. Salivary NRC was found to be diminished in periodontal patients before treatment (P < 0.05) but recovered to healthy levels 90 days post-treatment. Additionally, the subgingival levels of nitrate-reducing bacteria increased after treatment and correlated negatively with periodontitis-associated bacteria (P < 0.01). No significant effect of periodontal treatment on the baseline saliva and plasma nitrate and nitrite levels was found, indicating that differences in the NRC may only be revealed after nitrate intake. Our results suggest that an impaired NRC in periodontitis could limit dietary nitrate-derived nitric oxide levels, and the effect on systemic health should be explored in future studies.
Humans ; Nitrates ; Nitric Oxide ; Nitrites ; RNA, Ribosomal, 16S/genetics* ; Periodontitis/microbiology* ; Bacteria ; Dental Plaque/microbiology* ; Saliva/microbiology* ; Microbiota/genetics*

NAD(P)H: quinone oxidoreductase 1 (NQO1) is a flavin protease highly expressed in various cancer cells. NQO1 catalyzes a futile redox cycle in substrates, leading to substantial reactive oxygen species (ROS) production. This ROS generation results in extensive DNA damage and elevated poly (ADP-ribose) polymerase 1 (PARP1)-mediated consumption of nicotinamide adenine dinucleotide (NAD⁺), ultimately causing cell death. Nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme in the NAD⁺ salvage synthesis pathway, emerges as a critical target in cancer therapy. The concurrent inhibition of NQO1 and NAMPT triggers hyperactivation of PARP1 and intensive NAD⁺ depletion. In this study, we designed, synthesized, and assessed a novel series of proqodine A derivatives targeting both NQO1 and NAMPT. Among these, compound T8 demonstrated potent antitumor properties. Specifically, T8 selectively inhibited the proliferation of MCF-7 cells and induced apoptosis through mechanisms dependent on both NQO1 and NAMPT. This discovery offers a promising new molecular entity for advancing anticancer research.
Humans ; NAD/metabolism* ; Cell Line, Tumor ; Reactive Oxygen Species/metabolism* ; Nicotinamide Phosphoribosyltransferase/metabolism* ; Cytokines/metabolism* ; Quinones ; Oxidoreductases

BACKGROUND: Metabolic Dysfunction-associated Steatotic Liver Disease (MASLD) has become a global epidemic, and air pollution has been identified as a potential risk factor. This study aims to investigate the non-linear relationship between ambient air pollution and MASLD prevalence. METHOD: In this cross-sectional study, participants undergoing health checkups were assessed for three-year average air pollution exposure. MASLD diagnosis required hepatic steatosis with at least 1 out of 5 cardiometabolic criteria. A stepwise approach combining data visualization and regression modeling was used to determine the most appropriate link function between each of the six air pollutants and MASLD. A covariate-adjusted six-pollutant model was constructed accordingly. RESULTS: A total of 131,592 participants were included, with 40.6% met the criteria of MASLD. "Threshold link function," "interaction link function," and "restricted cubic spline (RCS) link functions" best-fitted associations between MASLD and PM_2.5, PM₁₀/CO, and O₃ /SO₂/NO₂, respectively. In the six-pollutant model, significant positive associations were observed when pollutant concentrations were over: 34.64 µg/m³ for PM_2.5, 57.93 µg/m³ for PM₁₀, 56 µg/m³ for O₃, below 643.6 µg/m³ for CO, and within 33 and 48 µg/m³ for NO₂. The six-pollutant model using these best-fitted link functions demonstrated superior model fitting compared to exposure-categorized model or linear link function model assuming proportionality of odds. CONCLUSION Non-linear associations were found between air pollutants and MASLD prevalence. PM_2.5, PM₁₀, O₃, CO, and NO₂ exhibited positive associations with MASLD in specific concentration ranges, highlighting the need to consider non-linear relationships in assessing the impact of air pollution on MASLD.
Humans ; Nitrogen Dioxide ; Cross-Sectional Studies ; Air Pollution/analysis* ; Air Pollutants/analysis* ; Particulate Matter/analysis* ; Liver Diseases ; Environmental Exposure/analysis*

OBJECTIVE: To investigate the effects of asperuloside on cervical cancer based on endoplasmic reticulum (ER) stress and mitochondrial pathway. METHODS: Different doses (12.5-800 µg/mL) of asperuloside were used to treat cervical cancer cell lines Hela and CaSki to calculate the half maximal inhibitory concentration (IC₅₀) of asperuloside. The cell proliferation was analyzed by clone formation assay. Cell apoptosis, intracellular reactive oxygen species (ROS) and mitochondrial membrane potential were determined by flow cytometry. The protein expressions of cleaved-caspase-3, Bcl-2, Bax, Cyt-c, cleaved-caspase-4 and glucose-regulated protein 78 (GRP78) were analyzed by Western blot. And the inhibitor of ER stress, 4-phenyl butyric acid (4-PBA) was used to treat cervical cancer cells to further verify the role of ER stress in the apoptosis of cervical cancer cells induced by asperuloside. RESULTS: Asperuloside of 325, 650, and 1300 µg/mL significantly inhibited the proliferation and promoted apoptosis of Hela and CaSki cells (P<0.01). All doses of asperuloside significantly increased intracellular ROS levels, reduced mitochondrial membrane potential, significantly reduced Bcl-2 protein expression level, and increased Bax, Cyt-c, GRP78 and cleaved-caspase-4 expressions (P<0.01). In addition, 10 mmol/L 4-PBA treatment significantly promoted cell proliferation and reduced apoptosis (P<0.05), and 650 µg/mL asperuloside could reverse 4-PBA-induced increased cell proliferation, decreased apoptosis and cleaved-caspase-3, -4 and GRP78 protein expressions (P<0.05). CONCLUSION Our study revealed the role of asperuloside in cervical cancer, suggesting that asperuloside promotes apoptosis of cervical cancer cells through ER stress-mitochondrial pathway.
Female ; Humans ; Uterine Cervical Neoplasms/metabolism* ; Caspase 3/metabolism* ; bcl-2-Associated X Protein/metabolism* ; Reactive Oxygen Species/metabolism* ; Endoplasmic Reticulum Chaperone BiP ; HeLa Cells ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; Apoptosis ; Endoplasmic Reticulum Stress ; Cell Line, Tumor

The widespread of tigecycline resistance gene tet(X4) has a serious impact on the clinical efficacy of tigecycline. The development of effective antibiotic adjuvants to combat the looming tigecycline resistance is needed. The synergistic activity between the natural compound β-thujaplicin and tigecycline in vitro was determined by the checkerboard broth microdilution assay and time-dependent killing curve. The mechanism underlining the synergistic effect between β-thujaplicin and tigecycline against tet(X4)-positive Escherichia coli was investigated by determining cell membrane permeability, bacterial intracellular reactive oxygen species (ROS) content, iron content, and tigecycline content. β-thujaplicin exhibited potentiation effect on tigecycline against tet(X4)-positive E. coli in vitro, and presented no significant hemolysis and cytotoxicity within the range of antibacterial concentrations. Mechanistic studies demonstrated that β-thujaplicin significantly increased the permeability of bacterial cell membranes, chelated bacterial intracellular iron, disrupted the iron homeostasis and significantly increased intracellular ROS level. The synergistic effect of β-thujaplicin and tigecycline was identified to be related to interfere with bacterial iron metabolism and facilitate bacterial cell membrane permeability. Our studies provided theoretical and practical data for the application of combined β-thujaplicin with tigecycline in the treatment of tet(X4)-positive E. coli infection.
Humans ; Tigecycline/pharmacology* ; Escherichia coli/metabolism* ; Reactive Oxygen Species/therapeutic use* ; Plasmids ; Anti-Bacterial Agents/metabolism* ; Escherichia coli Infections/microbiology* ; Bacteria/genetics* ; Microbial Sensitivity Tests

To investigate the protective effect and the potential mechanism of leonurine(Leo) against erastin-induced ferroptosis in human renal tubular epithelial cells(HK-2 cells), an in vitro erastin-induced ferroptosis model was constructed to detect the cell viability as well as the expressions of ferroptosis-related indexes and signaling pathway-related proteins. HK-2 cells were cultured in vitro, and the effects of Leo on the viability of HK-2 cells at 10, 20, 40, 60, 80 and 100 μmol·L~(-1) were examined by CCK-8 assay to determine the safe dose range of Leo administration. A ferroptosis cell model was induced by erastin, a common ferroptosis inducer, and the appropriate concentrations were screened. CCK-8 assay was used to detect the effects of Leo(20, 40, 80 μmol·L~(-1)) and positive drug ferrostatin-1(Fer-1, 1, 2 μmol·L~(-1)) on the viability of ferroptosis model cells, and the changes of cell morphology were observed by phase contrast microscopy. Then, the optimal concentration of Leo was obtained by Western blot for nuclear factor erythroid 2-related factor 2(Nrf2) activation, and transmission electron microscope was further used to detect the characteristic microscopic morphological changes during ferroptosis. Flow cytometry was performed to detect reactive oxygen species(ROS), and the level of glutathione(GSH) was measured using a GSH assay kit. The expressions of glutathione peroxidase 4(GPX4), p62, and heme oxygenase 1(HO-1) in each group were quantified by Western blot. RESULTS:: showed that Leo had no side effects on the viability of normal HK-2 cells in the concentration range of 10-100 μmol·L~(-1). The viability of HK-2 cells decreased as the concentration of erastin increased, and 5 μmol·L~(-1) erastin significantly induced ferroptosis in the cells. Compared with the model group, Leo dose-dependently increased cell via-bility and improved cell morphology, and 80 μmol·L~(-1) Leo promoted the translocation of Nrf2 from the cytoplasm to the nucleus. Further studies revealed that Leo remarkably alleviated the characteristic microstructural damage of ferroptosis cells caused by erastin, inhibited the release of intracellular ROS, elevated GSH and GPX4, promoted the nuclear translocation of Nrf2, and significantly upregulated the expression of p62 and HO-1 proteins. In conclusion, Leo exerted a protective effect on erastin-induced ferroptosis in HK-2 cells, which might be associated with its anti-oxidative stress by activating p62/Nrf2/HO-1 signaling pathway.
Humans ; Ferroptosis ; Reactive Oxygen Species/metabolism* ; NF-E2-Related Factor 2/metabolism* ; Sincalide/pharmacology* ; Signal Transduction ; Epithelial Cells/metabolism* ; Glutathione

This study aimed to explore the effects and mechanisms of total flavones of Abelmoschus manihot(TFA), the extracts from traditional Chinese medicine indicated for kidney diseases, on insulin resistance(IR) and podocyte epithelial-mesenchymal transition(EMT) in diabetic kidney disease(DKD), and further to reveal the scientific connotation. Thirty-two rats were randomly divided into a normal group, a model group, a TFA group, and a rosiglitazone(ROS) group. The modified DKD model was induced in rats by methods including high-fat diet feeding, unilateral nephrectomy, and streptozotocin(STZ) intraperitoneal injection. After modeling, the rats in the four groups were given double-distilled water, TFA suspension, and ROS suspension correspondingly by gavage every day. At the end of the 8th week of drug administration, all rats were sacrificed, and the samples of urine, blood, and kidney tissues were collected. The parameters and indicators related to IR and podocyte EMT in the DKD model rats were examined and observed, including the general condition, body weight(BW) and kidney weight(KW), the biochemical parameters and IR indicators, the protein expression levels of the key signaling molecules and structural molecules of slit diaphragm in the renal insulin receptor substrate(IRS) 1/phosphatidylinositol 3-kinase(PI3K)/serine-threonine kinase(Akt) pathway, foot process form and glomerular basement membrane(GBM) thickness, the expression of the marked molecules and structural molecules of slit diaphragm in podocyte EMT, and glomerular histomorphological characteristics. The results showed that for the DKD model rats, both TFA and ROS could improve the general condition, some biochemical parameters, renal appearance, and KW. The ameliorative effects of TFA and ROS were equivalent on BW, urinary albumin(UAlb)/urinary creatinine(UCr), serum creatinine(Scr), triglyceride(TG), and KW. Secondly, they could both improve IR indicators, and ROS was superior to TFA in improving fast insulin(FIN) and homeostasis model assessment of insulin resistance(HOMA-IR). Thirdly, they could both improve the protein expression levels of the key signaling molecules in the IRS1/PI3K/Akt pathway and glomerulosclerosis in varying degrees, and their ameliorative effects were similar. Finally, both could improve podocyte injury and EMT, and TFA was superior to ROS. In conclusion, this study suggested that podocyte EMT and glomerulosclerosis could be induced by IR and the decreased activation of the IRS1/PI3K/Akt pathway in the kidney in DKD. Similar to ROS, the effects of TFA in inhibiting podocyte EMT in DKD were related to inducing the activation of the IRS1/PI3K/Akt pathway and improving IR, which could be one of the scientific connotations of TFA against DKD. This study provides preliminary pharmacological evidence for the development and application of TFA in the field of diabetic complications.
Rats ; Animals ; Diabetic Nephropathies/drug therapy* ; Proto-Oncogene Proteins c-akt/metabolism* ; Phosphatidylinositol 3-Kinases/metabolism* ; Abelmoschus/chemistry* ; Podocytes ; Rats, Sprague-Dawley ; Epithelial-Mesenchymal Transition ; Flavones/pharmacology* ; Insulin Resistance ; Reactive Oxygen Species ; Diabetes Mellitus

Renal tubular injury in patients with diabetic kidney disease(DKD) may be accompanied by glomerular and microvascular diseases. It plays a critical role in the progression of renal damage in DKD, and is now known as diabetic tubulopathy(DT). To explore the multi-targeted therapeutic effects and pharmacological mechanisms in vivo of total flavones of Abelmoschus manihot(TFA), an extract from traditional Chinese medicine for treating kidney disease, in attenuating DT, the authors randomly divided all rats into four groups: a normal control group(normal group), a DT model group(model group), a DT model+TFA-treated group(TFA group) and a DT model+rosiglitazone(ROS)-treated group(ROS group). The DT rat model was established based on the DKD rat model by means of integrated measures. After successful modeling, the rats in the four groups were continuously given double-distilled water, TFA suspension, and ROS suspension, respectively by gavage every day. After 6 weeks of treatment, all rats were sacrificed, and the samples of their urine, blood, and kidneys were collected. The effects of TFA and ROS on various indicators related to urine and blood biochemistry, renal tubular injury, renal tubular epithelial cell apoptosis and endoplasmic reticulum stress(ERS), as well as the activation of the protein kinase R-like endoplasmic reticulum kinase(PERK)-eukaryotic translation initiation factor 2α(eIF2α)-activating transcription factor 4(ATF4)-C/EBP homologous protein(CHOP) signaling pathway in the kidney of the DT model rats were investigated. The results indicated that hypertrophy of renal tubular epithelial cells, renal tubular hyperplasia and occlusion, as well as interstitial extracellular matrix and collagen deposition occurred in the DT model rats. Moreover, significant changes were found in the expression degree and the protein expression level of renal tubular injury markers. In addition, there was an abnormal increase in tubular urine proteins. After TFA or ROS treatment, urine protein, the characteristics of renal tubular injury, renal tubular epithelial cell apoptosis and ERS, as well as the activation of the PERK-eIF2α-ATF4-CHOP signaling pathway in the kidney of the DT model rats were improved to varying degrees. Therein, TFA was superior to ROS in affecting the pathological changes in renal tubule/interstitium. In short, with the DT model rats, this study demonstrated that TFA could attenuate DT by multiple targets through inhibiting renal tubular ERS-induced cell apoptosis in vivo, and its effect and mechanism were related to suppressing the activation of the PERK-eIF2α-ATF4-CHOP signaling pathway in the kidney. These findings provided preliminary pharmacological evidence for the application of TFA in the clinical treatment of DT.
Rats ; Animals ; Abelmoschus ; Reactive Oxygen Species/metabolism* ; Flavones/pharmacology* ; Endoplasmic Reticulum Stress ; Diabetic Nephropathies/drug therapy* ; Apoptosis ; Diabetes Mellitus

This study aims to explore the neuroprotective mechanism of ginsenoside Re(GS-Re) on drosophila model of Parkinson's disease(PD) induced by rotenone(Rot). To be specific, Rot was used to induce PD in drosophilas. Then the drosophilas were grouped and respectively treated(GS-Re: 0.1, 0.4, 1.6 mmol·L~(-1); L-dopa: 80 μmol·L~(-1)). Life span and crawling ability of drosophilas were determined. The brain antioxidant activity [content of catalase(CAT), malondialdehyde(MDA), reactive oxygen species(ROS), superoxide dismutase(SOD)], dopamine(DA) content, and mitochondrial function [content of adenosine triphosphate(ATP), NADH:ubiquinone oxidoreductase subunit B8(NDUFB8) Ⅰ activity, succinate dehydrogenase complex, subunit B(SDHB) Ⅱ activity] were detected by enzyme-linked immunosorbent assay(ELISA). The number of DA neurons in the brains of drosophilas was measured with the immunofluorescence method. The levels of NDUFB8 Ⅰ, SDHB Ⅱ, cytochrome C(Cyt C), nuclear factor-E2-related factor 2(Nrf2), heme oxygenase-1(HO-1), B-cell lymphoma/leukemia 2(Bcl-2)/Bcl-2-assaciated X protein(Bax), and cleaved caspase-3/caspase-3 in the brain were detected by Western blot. The results showed that model group [475 μmol·L~(-1) Rot(IC_(50))] demonstrated significantly low survival rate, obvious dyskinesia, small number of neurons and low DA content in the brain, high ROS level and MDA content, low content of SOD and CAT, significantly low ATP content, NDUFB8 Ⅰ activity, and SDHB Ⅱ activity, significantly low expression of NDUFB8 Ⅰ, SDHB Ⅱ, and Bcl-2/Bax, large amount of Cyt C released from mitochondria to cytoplasm, low nuclear transfer of Nrf2, and significantly high expression of cleaved caspase-3/caspase-3 compared with the control group. GS-Re(0.1, 0.4, and 1.6 mmol·L~(-1)) significantly improved the survival rate of PD drosophilas, alleviated the dyskinesia, increased DA content, reduced the loss of DA neurons, ROS level, and MDA content in brain, improved content of SOD and CAT and antioxidant activity in brain, maintained mitochondrial homeostasis(significantly increased ATP content and activity of NDUFB8 Ⅰ and SDHB Ⅱ, significantly up-regulated expression of NDUFB8 Ⅰ, SDHB Ⅱ, and Bcl-2/Bax), significantly reduced the expression of Cyt C, increased the nuclear transfer of Nrf2, and down-regulated the expression of cleaved caspase-3/caspase-3. In conclusion, GS-Re can significantly relieve the Rot-induced cerebral neurotoxicity in drosophilas. The mechanism may be that GS-Re activates Keap1-Nrf2-ARE signaling pathway by maintaining mitochondrial homeostasis, improves antioxidant capacity of brain neurons, then inhibits mitochondria-mediated caspase-3 signaling pathway, and the apoptosis of neuronal cells, thereby exerting the neuroprotective effect.
Animals ; Reactive Oxygen Species/metabolism* ; Antioxidants/pharmacology* ; Oxidative Stress ; NF-E2-Related Factor 2/metabolism* ; Caspase 3/metabolism* ; Parkinson Disease/genetics* ; bcl-2-Associated X Protein/metabolism* ; Neuroprotective Agents/pharmacology* ; Kelch-Like ECH-Associated Protein 1/metabolism* ; Drosophila/metabolism* ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; Apoptosis ; Superoxide Dismutase/metabolism* ; Adenosine Triphosphate/pharmacology*

Microbial transformation is an efficient enzymatic approach for the structural modification of exogenous compounds to obtain derivatives. Compared with traditional chemical synthesis, the microbial transformation has in fact the undoubtable advantages of strong region-and stereo-selectivity, and a low environmental and economic impact on the production process, which can achieve the reactions challenging to chemical synthesis. Because microbes are equipped with a broad-spectrum of enzymes and therefore can metabolize various substrates, they are not only a significant route for obtaining novel active derivatives, but also an effective tool for mimicking mammal metabolism in vitro. Artemisinin, a sesquiterpene with a peroxy-bridged structure serving as the main active functional group, is a famous antimalarial agent discovered from Artemisia annua L. Some sesquiterpenoids, such as dihydroartemisinin, artemether, and arteether, have been developed on the basis of artemisinin, which have been successfully marketed and become the first-line antimalarial drugs recommended by WHO. As revealed by pharmacological studies, artemisinin and its derivatives have exhibited extensive biological activities, including antimalarial, antitumor, antiviral, anti-inflammatory, and immunomodulatory. As an efficient approach for structural modification, microbial transformation of artemisinin and its derivatives is an increasingly popular strategy that attracts considerable attention recently, and numerous novel derivatives have been discovered. Herein, this paper reviewed the microbial transformation of artemisinin and its artemisinin, including microbial strains, culture conditions, product isolation and yield, and biological activities, and summarized the advances in microbial transformation in obtaining active derivatives of artemisinin and the simulation of in vivo metabolism of drugs.
Animals ; Antimalarials/pharmacology* ; Antiviral Agents ; Artemether ; Artemisinins ; Mammals