Flavonol glycosides of Rosa multiflora regulates intestinal barrier function through inhibiting claudin expression in differentiated Caco-2 cells

Probing Long-Term Impacts: Low-Dose Polystyrene Nanoplastics Exacerbate Mitochondrial Health and Evoke Secondary Glycolysis via Repeated and Single Dosing

Nanoplastics (NPs) are omnipresent in the environment and contribute to human exposure. However, little is known regarding the long-term effects of NPs on human health. In this study, human intestinal Caco-2 cells were exposed to polystyrene nanoplastics (nanoPS) in an environmentally relevant concentration range (102-109 particles/mL) under two realistic exposure scenarios. In the first scenario, cells were repeatedly exposed to nanoPS every 2 days for 12 days to study the long-term effects. In the second scenario, only nanoPS was added once and Caco-2 cells were cultured for 12 days to study the duration of the initial effects of NPs. Under repeated dosing, initial subtle effects on mitochondria induced by low concentrations would accrue over consistent exposure to nanoPS and finally lead to significant impairment of mitochondrial respiration, mitochondrial mass, and cell differentiation process at the end of prolonged exposure, accompanied by significantly increased glycolysis over the whole exposure period. Single dosing of nanoPS elicited transient effects on mitochondrial and glycolytic functions, as well as increased reactive oxygen species (ROS) production in the early phase of exposure, but the self-recovery capacity of cells mitigated these effects at intermediate culture times. Notably, secondary effects on glycolysis and ROS production were observed during the late culture period, while the cell differentiation process and mitochondrial mass were not affected at the end. These long-term effects are of crucial importance for comprehensively evaluating the health hazards arising from lifetime exposure to NPs, complementing the extensively observed acute effects associated with prevalent short-term exposure to high concentrations. Our study underlines the need to study the toxicity of NPs in realistic long-term exposure scenarios such as repeated dosing.

A novel purgative mechanism of multiflorin A involves changing intestinal glucose absorption and permeability

BACKGROUND

Multiflorin A (MA) is a potential active ingredient of traditional herbal laxative, Pruni semen, with unusual purgative activity and an unclear mechanism, and inhibiting intestinal glucose absorption is a promising mechanism of novel laxatives. However, this mechanism still lacks support and a description of basic research.

PURPOSE

This study aimed to determine the main contribution of MA to the purgative activity of Pruni semen and elucidate the effect intensity, characteristics, site, and mechanism of MA in mice, and determine the novel mechanism of traditional herbal laxatives from the perspective of intestinal glucose absorption.

METHODS

We induced diarrhoea in mice by administering Pruni semen and MA, and the defecation behaviour, glucose tolerance, and intestinal metabolism were analysed. The effects of MA and its metabolite on peristalsis of the intestinal smooth muscle were evaluated using an intestinal motility assay in vitro. Intestinal tight junction proteins, aquaporins, and glucose transporters expression were analysed using immunofluorescence; gut microbiota and faecal metabolites were analysed using 16S rRNA and liquid chromatography-mass spectrometry.

RESULTS

MA administration (20 mg/kg) induced watery diarrhoea in over half of the experimental mice. The activity of MA in lowering peak postprandial glucose levels was synchronous with purgative action, with the acetyl group being the active moiety. MA was metabolised primarily in the small intestine, where it decreased sodium-glucose cotransporter-1, occludin, and claudin1 expression, then inhibited glucose absorption, resulting in a hyperosmotic environment. MA also increased the aquaporin3 expression to promote water secretion. Unabsorbed glucose reshapes the gut microbiota and their metabolism in the large intestine and the increasing gas and organic acid promoted defecation. After recovery, the intestinal permeability and glucose absorption function returned, and the abundance of probiotics such as Bifidobacterium increased.

CONCLUSION

The purgative mechanism of MA involves inhibiting glucose absorption, altering permeability and water channels to promote water secretion in the small intestine, and regulating gut microbiota metabolism in the large intestine. This study is the first systematic experimental study on the purgative effect of MA. Our findings provide new insight into the study of novel purgative mechanisms.

Artepillin C overcomes apalutamide resistance through blocking androgen signaling in prostate cancer cells

Prostate cancer has a relatively good prognosis, but most cases develop resistance to hormone therapy, leading to castration-resistant prostate cancer (CRPC). Androgen receptor (AR) antagonists and a cytochrome P450 17A1 inhibitor have been used to treat CRPC, but cancer cells readily develop resistance to these drugs. In this study, to improve the therapy of CRPC, we searched for natural compounds which block androgen signaling. Among cinnamic acid derivatives contained in Brazilian green propolis, artepillin C (ArtC) suppressed expressions of androgen-induced prostate-specific antigen and transmembrane protease serine 2 in a dose-dependent manner. Reporter assays revealed that ArtC displayed AR antagonist activity, albeit weaker than an AR antagonist flutamide. In general, aberrant activation of the androgen signaling is involved in the resistance of prostate cancer cells to hormone therapy. Recently, apalutamide, a novel AR antagonist, has been in clinical use, but its drug-resistant cases have been already reported. To search for compounds which overcome the resistance to apalutamide, we established apalutamide-resistant prostate cancer 22Rv1 cells (22Rv1/APA). The 22Rv1/APA cells showed higher AR expression and androgen sensitivity than parental 22Rv1 cells. ArtC inhibited androgen-induced proliferation of 22Rv1/APA cells by suppressing the enhanced androgen signaling through blocking the nuclear translocation of AR. In addition, ArtC potently sensitized the resistant cells to apalutamide by inducing apoptotic cell death due to mitochondrial dysfunction. These results suggest that the intake of Brazilian green propolis containing ArtC improves prostate cancer therapy.

Antiandrogenic Effects of a Polyphenol in Carex kobomugi through Inhibition of Androgen Synthetic Pathway and Downregulation of Androgen Receptor in Prostate Cancer Cell Lines

Prostate cancer (PC) represents the most common cancer disease in men. Since high levels of androgens increase the risk of PC, androgen deprivation therapy is the primary treatment; however this leads to castration-resistant PC (CRPC) with a poor prognosis. The progression to CRPC involves ectopic androgen production in the adrenal glands and abnormal activation of androgen signaling due to mutations and/or amplification of the androgen receptor (AR) as well as activation of androgen-independent proliferative pathways. Recent studies have shown that adrenal-derived 11-oxygenated androgens (11-ketotestosterone and 11-ketodihydrotestosterone) with potencies equivalent to those of traditional androgens (testosterone and dihydrotestosterone) are biomarkers of CRPC. Additionally, dehydrogenase/reductase SDR family member 11 (DHRS11) has been reported to be a 17β-hydroxysteroid dehydrogenase that catalyzes the production of the 11-oxygenated and traditional androgens. This study was conducted to evaluate the pathophysiological roles of DHRS11 in PC using three LNCaP, C4-2 and 22Rv1 cell lines. DHRS11 silencing and inhibition resulted in suppression of the androgen-induced expression of AR downstream genes and decreases in the expression of nuclear AR and the proliferation marker Ki67, suggesting that DHRS11 is involved in androgen-dependent PC cell proliferation. We found that 5,7-dihydroxy-8-methyl-2-[2-(4-hydroxyphenyl)ethenyl]-4H-1-benzopyran-4-one (Kobochromone A, KC-A), an ingredient in the flowers of Carex kobomugi, is a novel potent DHRS11 inhibitor (IC₅₀ = 0.35 μM). Additionally, KC-A itself decreased the AR expression in PC cells. Therefore, KC-A suppresses the androgen signaling in PC cells through both DHRS11 inhibition and AR downregulation. Furthermore, KC-A enhanced the anticancer activity of abiraterone, a CRPC drug, suggesting that it may be a potential candidate for the development of drugs for the prevention and treatment of CRPC.

Purified fish skin collagen hydrolysate attenuates TNF-α induced barrier dysfunction in-vitro and DSS induced colitis in-vivo model

Inflammatory mediators are key components in establishing pathogenesis in inflammatory bowel disease. Balanced expression of anti-inflammatory and pro-inflammatory cytokines is an important cue in maintaining gut native and adaptive immunity. In the present study, purified hydrolysate fraction of fish skin collagen from Clarias batrachus and Pangasius pangasius was evaluated as a treatment agent against TNF-α induced barrier dysfunction in Caco-2 cell line model and DSS induced colitis in mice model. Cell adhesion on purified hydrolysate fraction coated surfaces was found to be enhanced with increasing concentration in both Clarias batrachus and Pangasius pangasius. Alkaline phosphatase activity was enhanced in a concentration-dependent manner. The paracellular permeability assay demonstrated that Pangasius pangasius purified hydrolysate fraction had countered TNF-α induced barrier dysfunction. Analysis of the tight junction proteins (occludin, zonulae occluden, and claudin) by RT PCR, immunofluorescence, and western blot, further confirmed the effectiveness of Pangasius pangasius purified hydrolysate fraction against TNF-α. The Pangasius pangasius purified hydrolysate fraction was further evaluated for efficacy in DSS-induced colitis mice model. Two concentration of Pangasius pangasius purified hydrolysate was chosen based on in-vitro experiments, 80 μg/kg and 200 μg/kg BW of Balb/C male mice administered through intra-rectal route along with fish skin collagen 80 μg/kg BW. Pangasius pangasius purified hydrolysate fraction treatment improved the clinical signs of colitis such as body weight, rectal bleeding, colon length, and stool consistency caused by DSS administration. Immunofluorescence of colon tissue section showed that Pangasius pangasius purified hydrolysate fraction enhanced the expression of occludin protein. This study hints at the use of Pangasius pangasius purified hydrolysate fraction as a potential nutraceutical or treatment agent in healing ulcers of the mucosa.

Evaluation of the chemical profile from four germplasms sources of Pruni Semen using UHPLC-LTQ-Orbitrap-MS and multivariate analysis

Pruni Semen, the seed of several unique Prunus plants, is a traditional purgative herbal material. To determine the authentic sources of Pruni Semen, 46 samples from four species were collected and analyzed. Ten compounds including multiflorin A (Mul A), a notable purative compound, were isolated and identified by chemical separation and nuclear magnetic resonance spectroscopy. Seventy-six communal components were identified by ultra-high performance liquid chromatography with linear ion trap-quadrupole Orbitrap mass spectrometry, and acetyl flavonoid glycosides were recognized as characteristic constituents. The flavonoids were distributed in the seed coat and cyanogenic glycosides in the kernel. Based on this, methods for identifying Pruni Semen from different sources were established using chemical fingerprinting, quantitative analysis of the eight principal compounds, hierarchical cluster analysis, principal component analysis, and orthogonal partial least squares discriminant analysis. The results showed that the samples were divided into two categories: one is the small seeds from Prunus humilis (Ph) and Prunus japonica (Pj), and the other is the big seeds from Prunus pedunculata (Pp) and Prunus triloba (Pt). The average content of Mul A was 3.02, 6.93, 0.40, and 0.29 mg/g, while the average content of amygdalin was 18.5, 17.7, 31.5, and 30.9 mg/g in Ph, Pj, Pp, and Pt, respectively. All the above information suggests that small seeds might be superior sources of Pruni Semen. This is the first comprehensive report on the identification of chemical components in Pruni Semen from different species.

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Chemical constituents of Pruni semen from four Prunus species were compared.

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Acetyl flavonoid glycosides were identified as the characteristic components.

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Flavonoids were present in the seed coat and cyanogenic glycosides in the kernel.

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The content of acetyl flavonoid in small seeds is significant higher than those in big ones.

Assessing Intestinal Health. In Vitro and Ex vivo Gut Barrier Models of Farm Animals: Benefits and Limitations

Animal performance is determined by the functionality and health of the gastrointestinal tract (GIT). Complex mechanisms and interactions are involved in the regulation of GIT functionality and health. The understanding of these relationships could be crucial for developing strategies to improve animal production yields. The concept of "gut health" is not well defined, but this concept has begun to play a very important role in the field of animal science. However, a clear definition of GIT health and the means by which to measure it are lacking. In vitro and ex vivo models can facilitate these studies, creating well-controlled and repeatable conditions to understand how to improve animal gut health. Over the years, several models have been developed and used to study the beneficial or pathogenic relationships between the GIT and the external environment. This review aims to describe the most commonly used animals' in vitro or ex vivo models and techniques that are useful for better understanding the intestinal health of production animals, elucidating their benefits and limitations.

Loxoprofen enhances intestinal barrier function via generation of its active metabolite by carbonyl reductase 1 in differentiated Caco-2 cells

Nonsteroidal anti-inflammatory drugs (NSAIDs) are used worldwide as antipyretic analgesics and agents for rheumatoid arthritis and osteoarthritis, but known to cause damage to the gastrointestinal mucosae as their serious adverse effects. Few studies showed the impairment of intestinal epithelial barrier function (EBF) by high concentrations (0.5-1 mM) of NSAIDs, but the underlying mechanism is not fully understood. This study is aimed at clarifying effects at a low concentration (50 μM) of three NSAIDs, loxoprofen (Lox), ibuprofen and indomethacin, on intestinal EBF using human intestinal epithelial-like Caco-2 cells. Among those NSAIDs, Lox increased the transepithelial electric resistance (TER) value, decreased the paracellular Lucifer yellow CH (LYCH) permeability, and upregulated claudin (CLDN)-1, -3 and -5, indicating that low doses of Lox enhanced EBF through increasing expression of CLDNs. Lox is known to be metabolized to a pharmacologically active metabolite, (2S,1'R,2'S)-loxoprofen alcohol (Lox-RS), by carbonyl reductase 1 (CBR1), which is highly expressed in human intestine. CBR1 was expressed in the Caco-2 cells, and the pretreatment with a CBR1 inhibitor suppressed both the Lox-evoked CLDN upregulation and EBF enhancement. In addition, the treatment of the cells with Lox-RS resulted in higher TER value and lower LYCH permeability than those with Lox. Thus, Lox-RS synthesized by CBR1 may greatly contribute to the improving efficacy of Lox on the barrier function. Since EBF is decreased in inflammatory bowel disease, we finally examined the effect of Lox on EBF using the Caco-2/THP-1 co-culture system, which is used as an in vitro inflammatory bowel disease model. Lox significantly recovered EBF which was impaired by inflammatory cytokines secreted from THP-1 macrophages. These in vitro observations suggest that Lox enhances intestinal EBF, for which the metabolism of Lox to Lox-RS by CBR1 has an important role.

Targeting Nrf2-antioxidant signaling reverses acquired cabazitaxel resistance in prostate cancer cells

Prostate cancer is known to have a relatively good prognosis, but long-term hormone therapy can lead to castration-resistant prostate cancer (CRPC). Cabazitaxel, a second-generation taxane, has been used for the CRPC treatment, but its tolerance is an urgent problem to be solved. In this study, to elucidate the acquisition mechanism of the cabazitaxel-resistance, we established cabazitaxel-resistant prostate cancer 22Rv1 (Cab-R) cells, which exhibited approximately 7-fold higher LD50 against cabazitaxel than the parental 22Rv1 cells. Cab-R cells showed marked increases in nuclear accumulation of NF-E2 related factor 2 (Nrf2) and expression of Nrf2-inducible antioxidant enzymes compared to 22Rv1 cells, suggesting that Nrf2 signaling is homeostatically activated in Cab-R cells. The cabazitaxel sensitivity of Cab-R cells was enhanced by silencing of Nrf2, and that of 22Rv1 cells was reduced by activation of Nrf2. Halofuginone (HF) has been recently identified as a potent Nrf2 synthetic inhibitor, and its treatment of Cab-R cells not only suppressed the Nrf2 signaling by decreasing both nuclear and cytosolic Nrf2 protein levels, but also significantly augmented the cabazitaxel sensitivity. Thus, inhibition of Nrf2 signaling may be effective in overcoming the cabazitaxel resistance in prostate cancer cells.