Display omitted
•Caffeine ameliorates the lipid profiles of ovariectomized (OVX) rats.•Caffeine improves bone metabolism-related blood indicators in OVX rats.•Caffeine did not affect organ weights ...and coefficients or bone quality in OVX rats.•Caffeine did not exert a damaging effect on the skeletal system of OVX rats.
Caffeine (1,3,7-trimethylxanthine) is a naturally occurring plant xanthine alkaloid present in many commonly consumed beverages worldwide, including tea, coffee, and cocoa. Although moderate caffeine intake is generally considered to exert positive effects on human health, its effect on bone metabolism remains controversial. The aim of this study was to systematically evaluate the pharmacological effect of long-term administration of caffeine on ovariectomy-induced postmenopausal osteoporosis in female rats. A sham operation or ovariectomy was performed to establish the ovariectomy rat model. The ovariectomized (OVX) rats were divided into five subgroups: OVX with vehicle (model), OVX with raloxifene hydrochloride (RLX, positive control; 4 mg/kg body weight/day), and OVX with low-, medium-, and high-dose caffeine (9.6, 19.2, and 38.4 mg/kg of body weight/day, respectively). Their corresponding treatments were administered intragastrically for 13 weeks. In-vivo studies showed that treatment with caffeine effectively improved the lipid profiles and increased the concentration of calcium in the serum of OVX rats. Medium- or high-dose treatment with caffeine significantly decreased the activities of alkaline and acid phosphatases in OVX rats. In addition, treatment with caffeine (at any dose) did not adversely affect organ weights, organ coefficients, femoral length, bone mineral density, biomechanical properties, or bone microarchitecture in OVX rats. Collectively, our study demonstrated that caffeine did not exert a damaging effect on the skeletal system of OVX rats.
The tumor necrosis factor alpha (TNF-α)–TNF-α receptor (TNFR) interaction plays a central role in the pathogenesis of various autoimmune diseases, particularly rheumatoid arthritis, and is therefore ...considered a key target for drug discovery. However, natural compounds that can specifically block the TNF-α–TNFR interaction are rarely reported. (-)-Epigallocatechin-3-gallate (EGCG) is the most active, abundant, and thoroughly investigated polyphenolic compound in green tea. However, the molecular mechanism by which EGCG ameliorates autoimmune arthritis remains to be elucidated. In the present study, we found that EGCG can directly bind to TNF-α, TNFR1, and TNFR2 with similar μM affinity and disrupt the interactions between TNF-α and TNFR1 and TNFR2, which inhibits TNF-α-induced L929 cell death, blocks TNF-α-induced NF-κB activation in 293-TNF-α response cell line, and eventually leads to inhibition of TNF-α-induced NF-κB signaling pathway in HFLS and MH7A cells. Thus, regular consumption of EGCG in green tea may represent a potential therapeutic agent for the treatment of TNF-α-associated diseases.
Display omitted
•EGCG directly binds to TNF-α, TNFR1, and TNFR2 with similar μM affinity.•EGCG disrupts the interactions between TNF-α and TNFR1 and TNFR2.•EGCG inhibits TNF-α-induced L929 cell death and blocks TNF-α-induced NF-κB activation in 293-TNF-α response cell line.•EGCG inhibits TNF-α-induced NF-κB signaling pathway in HFLS and MH7A cells.•EGCG can’t inhibit LPS-induced NF-κB activation in HFLS and MH7A cells.
Display omitted
•Caffeine promoted growth and migration of paclitaxel-treated cancer cells.•Caffeine inhibited apoptosis in paclitaxel-treated cancer cells.•Caffeine down-regulated paclitaxel-induced ...α-tubulin acetylation in vitro and in vivo.•Caffeine decreased paclitaxel-induced inhibition of tumor growth.
Caffeine (1,3,7-trimethylxanthine) is a xanthine alkaloid found in a number of dietary products consumed worldwide, such as coffee, tea, and soft beverages, and is known to act as a modifying agent for cytotoxic chemotherapeutic drugs. Studies have shown that caffeine reduces the cytotoxic effects of paclitaxel and inhibits paclitaxel-induced apoptosis; however, the underlying mechanism remains unclear. Here, we investigated whether caffeine inhibits the antitumor activity of paclitaxel via down-regulation of α-tubulin acetylation. In vitro studies, involving MTT assay, wound-healing assay, cell apoptosis assay, and western blotting analysis of A549 and HeLa cells, were performed. A549 and HeLa cell-based xenografts were established, and western blotting and immunohistochemical staining were performed for in vivo studies. The results showed that caffeine promoted the growth of cancer cells treated with paclitaxel. Additionally, caffeine enhanced migration ability, inhibited apoptosis, and decreased the acetylation of α-tubulin in paclitaxel-treated cancer cells. Furthermore, caffeine decreased the inhibitory effect of paclitaxel on tumor growth through down-regulation of α-tubulin acetylation in vivo. Taken together, these findings demonstrate that caffeine inhibits the anticancer activity of paclitaxel via down-regulation of α-tubulin acetylation, suggesting that patients receiving treatment with taxanes, such as paclitaxel, should avoid consuming caffeinated beverages or foods.
Caffeine is chemically stable and not readily oxidized under normal physiological conditions but also has antioxidant effects, although the underlying molecular mechanism is not well understood. ...Superoxide dismutase (SOD) 2 is a manganese-containing enzyme located in mitochondria that protects cells against oxidative stress by scavenging reactive oxygen species (ROS). SOD2 activity is inhibited through acetylation under conditions of stress such as exposure to ultraviolet (UV) radiation. Sirtuin 3 (SIRT3) is the major mitochondrial nicotinamide adenine dinucleotide (NAD
+
)-dependent deacetylase, which deacetylates two critical lysine residues (lysine 68 and lysine 122) on SOD2 and promotes its antioxidative activity. In this study, we investigated whether the antioxidant effect of caffeine involves modulation of SOD2 by SIRT3 using
in vitro
and
in vivo
models. The results show that caffeine interacts with SIRT3 and promotes direct binding of SIRT3 with its substrate, thereby enhancing its enzymatic activity. Mechanistically, caffeine bound to SIRT3 with high affinity (
K
D
= 6.858 × 10
–7
M); the binding affinity between SIRT3 and its substrate acetylated p53 was also 9.03 (without NAD
+
) or 6.87 (with NAD
+
) times higher in the presence of caffeine. Caffeine effectively protected skin cells from UV irradiation-induced oxidative stress. More importantly, caffeine enhanced SIRT3 activity and reduced SOD2 acetylation, thereby leading to increased SOD2 activity, which could be reversed by treatment with the SIRT3 inhibitor 3-(1H-1,2,3-triazol-4-yl) pyridine (3-TYP)
in vitro
and
in vivo
. Taken together, our results show that caffeine targets SIRT3 to enhance SOD2 activity and protect skin cells from UV irradiation-induced oxidative stress. Thus, caffeine, as a small-molecule SIRT3 activator, could be a potential agent to protect human skin against UV radiation.
Vip3Aa proteins produced by three different Bt strains, including an industrial strain, were retained in the mother cell compartment. However in rich medium, a fraction of Vip3Aa was secreted, ...suggesting that Vip3Aa secretion is nutrient‐dependent. Hence, we speculate that the accumulation of Vip3Aa protein in the mother cell compartment under sporulation conditions could still be used as an efficient strategy for industrial production in commercial Bt strains.
Summary
Vip3Aa was first identified as a protein secreted during the vegetative growth phase of Bacillus thuringiensis (Bt) bacteria and which shows high insecticidal toxicity against lepidopteran insect pests (Estruch et al., 1996). Bt strains formulated as bio‐insecticides only had low amounts of Vip3Aa secreted to the medium. Here, we report that Vip3Aa proteins produced by three different Bt strains, including an industrial strain, were indeed not secreted to the culture solution when grown in sporulation medium, but were retained in the mother cell compartment. In order to further investigate the Vip3Aa secretion and location, we grew the strains in rich medium. We found that in rich medium, a fraction of Vip3Aa was secreted, suggesting that Vip3Aa secretion is nutrient‐dependent. Regardless of the growth conditions, we found that Vip3Aa retained in cell pellets exhibited high toxicity against Spodoptera frugiperda larvae. Hence, we speculate that the accumulation of Vip3Aa protein in the mother cell compartment under sporulation conditions could still be used as an efficient strategy for industrial production in commercial Bt strains.
Existing studies have shown that sacubitril-valsartan ameliorated atrial remodeling in atrial fibrillation (AF) and favored maintenance of sinus rhythm in patients with AF and heart failure. However, ...the effect of sacubitril-valsartan in patients with persistent AF is yet unknown. We aimed to evaluate the effect of sacubitril-valsartan on restoration and maintenance of sinus rhythm in patients with persistent AF who underwent electrical cardioversion (ECV).
Consecutive patients with persistent AF who underwent ECV between 1 January 2016 and 30 September 2020 were investigated in this retrospective cohort study. All eligible patients were categorized into sacubitril-valsartan users and sacubitril-valsartan non-users based on whether they received treatment with sacubitril-valsartan or not. The endpoint was ineffictive ECV, defined as the composite of failure to terminate AF or any recurrence of AF during 30 days follow-up.
A total of 76 patients were enrolled in this study, including 28 sacubitril-valsartan users and 48 non-users. Within a follow-up of 30 days after ECV, the endpoint had occurred in 7 (25%) of 28 sacubitril-valsartan users and 25 (52%) of 48 non-users. Significantly lower rate of ineffictive ECV in sacubitril-valsartan users compared with non-users was shown in Kaplan-Meier survival curves (
= 0.02; Log-rank test). Multivariate Cox regression analysis indicated that sacubitril-valsartan use (hazard ratio HR, 0.35; 95% confidence interval CI, 0.14-0.91), amiodarone use (HR, 0.32; 95% CI, 0.13-0.78), left atrial diameter ≤ 39 mm (HR, 0.21; 95% CI, 0.06-0.71) were independently associated with a decreased rate of ineffective electrical cardioversion.
Abstract
Mechanical equipment in actual motion can produce noise interference with the vibration signal of rolling bearings, which have non-constant loads and speed. These factors lead to variable ...and unstable vibration signals of rolling bearings; therefore, it is very difficult to accurately diagnose actual running rolling bearings. In this paper, a residual denoising dynamic adaptation network (RDDAN) is proposed, which uses the signal knowledge under known working conditions to diagnose rolling bearing faults under unknown working conditions. The method mainly consists of data preprocessing, feature extraction, and dynamic distribution adaptation. First, Gaussian noise is added at the data preprocessing stage to emulate the noise perturbation during the reality of rolling bearing operation. Secondly, a deep residual shrinkage network is used for noise reduction and feature extraction. Finally, the marginal probability distribution and conditional probability distribution under different working conditions are calculated, depending on the characteristics. The network is disciplined using the relative weight of the marginal probability distribution and the conditional probability distribution. And the fault classification results are output after multiple iterations. The method was tested on the Case Western Reserve University bearing dataset and the Machine Fault Simulator Magnum bearing dataset, respectively. In comparison with other models, the RDDAN improves the average accuracy by about 23%. The results show that the RDDAN can effectively solve the problem of inconsistent data distribution in rolling bearings under operating conditions influenced by multiple variables such as noise, load, and speed.
Crystalline (Cry) proteins from the bacterium Bacillus thuringiensis (Bt) are widely used in transgenic crops to control important insect pests. Bt crops have many benefits compared with traditional ...broad-spectrum insecticides, including improved pest control with reduced negative impacts on off-target organisms and fewer environmental consequences. Transgenic corn and cotton producing Cry2Ab Bt toxin are used globally to control several major lepidopteran pests, including the cotton bollworm, Helicoverpa armigera. Resistance to the Cry2Ab toxin and to Bt crops producing Cry2Ab is associated with mutations in the midgut ATP-binding cassette transporter ABCA2 gene in several lepidopterans. Gene-editing knockout has further shown that ABCA2 plays an important functional role in Cry2Ab intoxication. However, the precise role of ABCA2 in the mode of action of Cry2Ab has yet to be reported. Here, we used two in vitro expression systems to study the roles of the H. armigera ABCA2 (HaABCA2) protein in Cry2Ab intoxication. Cry2Ab bound to cultured Sf9 insect cells producing HaABCA2, resulting in specific and dose-dependent susceptibility to Cry2Ab. In contrast, Sf9 cells expressing recombinant mutant proteins missing at least one of the extracellular loop regions 1, 3, 4, and 6 or the intracellular loop containing nucleotide-binding domain 1 lost susceptibility to Cry2Ab, indicating these regions are important for receptor function. Consistent with these results, Xenopus laevis oocytes expressing recombinant HaABCA2 showed strong ion membrane flux in the presence of Cry2Ab, suggesting that HaABCA2 is involved in promoting pore formation during Cry2Ab intoxication. Together with previously published data, our results support HaABCA2 being an important receptor of Cry2Ab where it functions to promote intoxication in H. armigera.
Background
Skin photoaging is the damage caused by excessive exposure to ultraviolet (UV) irradiation. We investigated the effect of adenosine triphosphate (ATP) supplementation on UVB‐induced ...photoaging in HaCaT cells and its potential molecular mechanism.
Materials and methods
The toxicity of ATP on HaCaT cells was examined by the MTT assay. The effects of ATP supplementation on the viability and apoptosis of HaCaT cells were determined by crystal‐violet staining and flow cytometry, respectively. Cellular and mitochondrial ROS were stained using fluorescent dyes. Expression of Bax, B‐cell lymphoma (Bcl)‐2, sirtuin (SIRT)3, and superoxide dismutase (SOD)2 was measured via western blotting.
Results
ATP (1, 2 mM) exerted no toxic effect on the normal growth of HaCaT cells. UVB irradiation caused the apoptosis of HaCaT cells, and ATP supplementation inhibited the apoptosis induced by UVB significantly, as verified by expression of Bax and Bcl‐2. UVB exposure resulted in accumulation of cellular and mitochondrial reactive oxygen species (ROS), but ATP supplementation suppressed these increases. Expression of SIRT3 and SOD2 was decreased upon exposure to UVB irradiation but, under ATP supplementation, expression of SIRT3 and SOD2 was reversed, which was consistent with the reduction in ROS level observed in ATP‐treated HaCaT cells after exposure to UVB irradiation.
Conclusions
ATP supplementation can suppress UVB irradiation‐induced photoaging in HaCaT cells via upregulation of expression of SIRT3 and SOD2.
Acanthopanax senticosus (Ciwujia) has broad-spectrum pharmacological activities, including osteoprotective effects. However, the mechanisms underlying these effects remain unclear. We investigated ...whether Acanthopanax senticosus aqueous extract (ASAE) ameliorates ovariectomy-induced bone loss in middle-aged mice through inhibition of osteoclastogenesis. In vitro, ASAE significantly suppressed the receptor activator of nuclear factor-κB ligand (RANKL)-stimulated osteoclast differentiation and formation of F-actin rings by downregulating the expression of the nuclear factor of activated T cells, cytoplasmic 1 (NFATc1), c-Fos, and osteoclastogenesis-related marker genes and proteins, including c-Src, tartrate-resistant acid phosphatase (TRAP), cathepsin K, β3-integrin, and matrix metallopeptidase-9 (MMP-9). This was achieved by inhibiting RANK signaling pathways, including p65, c-Jun N-terminal kinase, extracellular signal-regulated kinase, and p38 in osteoclast precursors. In vivo, ASAE markedly ameliorated bone loss in ovariectomized (OVX) middle-aged mice. ASAE significantly inhibited the serum levels of tartrate-resistant acid phosphatase 5b (TRACP-5b) and RANKL, whereas it increased those of osteocalcin, procollagen 1 N-terminal peptide (P1NP), and osteoprotegerin in OVX mice. ASAE significantly inhibited the OVX-induced expression of osteoclast-specific proteins and genes in the femur. In conclusion, ASAE prevents ovariectomy-induced bone loss in middle-aged mice by inhibiting RANKL-induced osteoclastogenesis through suppression of RANK signaling pathways and could be potentially used in mediated treatment of osteoclast-related diseases (e.g., osteoporosis).
PDF
