Anti-necroptosis and anti-ferroptosis compounds from the Deep-Sea-Derived fungus Aspergillus sp. MCCC 3A00392.

Eight undescribed (1-8) and 46 known compounds (9-54) were isolated from the deep-sea-derived Aspergillus sp. MCCC 3A00392. Compounds 1-3 were three novel oxoindolo diterpenoids, 4-6 were three bisabolane sesquiterpenoids, while 7 and 8 were two monocyclic cyclopropanes. Their structures were established by exhaustive analyses of the HRESIMS, NMR, and theoretical calculations of the NMR data and ECD spectra. Compounds 10, 33, 38, and 39 were able to inhibit tumor necrosis factor (TNF)-induced necroptosis in murine L929 cell lines. Functional experiments verified that compounds 10 and 39 inhibited necroptosis by downregulating the phosphorylation of RIPK3 and MLKL. Moreover, compound 39 also reduced the phosphorylation of RIPK1. Compounds 10, 33, and 34 displayed potent inhibitory activities against RSL-3 induced ferroptosis with the EC50 value of 3.0 µM, 0.4 µM, and 0.1 µM, respectively. Compound 10 inhibited ferroptosis by the downregulation of HMOX1, while compounds 33 and 34 inhibited ferroptosis through regulation of NRF2/SLC7A11/GCLM axis. However, these compounds only showed weak effect in either the necroptosis or ferroptosis relative mouse disease models. Further studies of pharmacokinetics and pharmacodynamics might improve their in vivo bioactivities.

Chemical Constituents of the Deep-sea Gammarid Shrimp-Derived Fungus Penicillium citrinum XIA-16.

One new alkaloid, (S)-2-acetamido-4-(2-(methylamino)phenyl)-4-oxobutanoic acid (1), was isolated from the deep-sea-derived Penicillium citrinum XIA-16, together with 25 known compounds including ten polyketones (2-11), eight alkaloids (12-19), six steroids (20-25), and a fatty acid (26). Their planar and relative structures were determined by an analysis of 1D and 2D nuclear magnetic resonance (NMR) as well as high resolution electrospray ionization mass spectroscopy (HR-ESI-MS) data. The absolute configuration of 1 was determined by comparison of the experimental and calculated electronic circular dichroism (ECD) spectra. Penicitrinol B (6) significantly inhibited RSL3-induced ferroptosis (EC50 =2.0 µM) by reducing lipid peroxidation and heme oxygenase 1 (HMOX1) expression. Under the concentration of 10 µM, penicitrinol A (7) was able to inhibit cuproptosis with the cell viabilities of 68.2 % compared to the negative control (copper and elesclomol) with the cell viabilities of 14.8 %.

Icariin, a phosphodiesterase-5 inhibitor, improves learning and memory in APP/PS1 transgenic mice by stimulation of NO/cGMP signalling.

Phosphodiesterase-5 (PDE5) inhibitors are predominantly used in the treatment of erectile dysfunction, and have been recently shown to have a potential therapeutic effect for the treatment of Alzheimer's disease (AD) through stimulation of nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) signalling by elevating cGMP, which is a secondary messenger involved in processes of neuroplasticity. In the present study, the effects of a PDE5 inhibitor, icarrin (ICA), on learning and memory as well as the pathological features in APP/PS1 transgenic AD mice were investigated. Ten-month-old APP/PS1 transgenic mice overexpressing human amyloid precursor protein (APP695swe) and presenilin 1 (PS1-dE9) were given ICA (30 and 60 mg/kg) or sildenafil (SIL) (2 mg/kg), age-matched wild-type (WT) mice were given ICA (60 mg/kg), and APP/PS1 and WT control groups were given an isovolumic vehicle orally twice a day for four months. Results demonstrated that ICA treatments significantly improved learning and memory of APP/PS1 transgenic mice in Y-maze tasks. The amyloid precursor protein (APP), amyloid-beta (Aß1-40/42) and PDE5 mRNA and/or protein levels were increased in the hippocampus and cortex of APP/PS1 mice, and ICA treatments decreased these physiopathological changes. Furthermore, ICA-treated mice showed an increased expression of three nitric oxide synthase (NOS) isoforms at both mRNA and protein levels, together with increased NO and cGMP levels in the hippocampus and cortex of mice. These findings demonstrate that ICA improves learning and memory functions in APP/PS1 transgenic mice possibly through the stimulation of NO/cGMP signalling and co-ordinated induction of NOS isoforms.

Effect of icariin on UDP-glucuronosyltransferases in mouse liver.

Icariin is a flavonol glycoside isolated from Epimedium genus and has been used in the treatment of sexual dysfunction and osteoporosis. Our laboratory has shown that icariin is beneficial in brain disorders and cardiovascular diseases. Since icariin is widely used with other herbs and drugs, to understand its potential herb-drug interactions is of importance. Recently, icariin was shown to inhibit UDP-glucuronosyltransferases, particularly the Ugt1 family enzymes in vitro, but little is known about such effects in vivo. This study investigated the effects of icariin on the expression of UDP-glucuronosyltransferases and cytochrome P450 enzymes in the livers of mice. Adult mice were treated with icariin at doses of 0, 40, 80, 160, and 320 mg/kg, p. o., for 7 days. Phenobarbital (120 mg/kg, p.o.) and rifampin (360 mg/kg, p. o.) were given twice daily for 3 days as positive controls. The livers were removed to determine UDP-glucuronosyltransferase activity and total RNA isolation. The UDP-glucuronosyltransferase activities towards 2-aminophenol were basically unaltered by the treatments. The expression of Cyp2b10 was increased 35-fold by phenobarbital, and Cyp3a11 was increased 4.5-fold by rifampin. Icariin did not affect Cyp2b10 and Cyp3a11 expression, but unexpectedly increased Cyp4a14 expression. Both phenobarbital and rifampin increased Ugt1a1, Ugt1a6, Ugt1a9, and icariin but did not show any suppressive effects on the Ugt1 family genes. Icariin at the highest dose (320 mg/kg) slightly increased Ugt2b1, Ugt2b5, and Ugt2b36. These findings indicate that icariin did not suppress UDP-glucuronosyltransferase expression, instead, it increased the mRNA of Cyp4a14 and slightly increased Ugt2b isoforms in mouse livers.

Stephaochratidin A, a Rare Stephacidin-Asperochratide Hybrid with Ferroptosis Inhibitory Activity from the Deep-Sea-Derived Aspergillus ochraceus.

One rare stephacidin-asperochratide hybrid, stephaochratidin A (1), was isolated from the deep-sea-derived Aspergillus ochraceus MCCC 3A00521. The relative structure of 1 was determined by comprehensive analyses of its 1D and 2D NMR data as well as HRESIMS data. And the absolute configuration was unambiguously assigned by ECD calculations and the X-ray single-crystal diffraction analysis. Plausible biosynthetic pathway of 1 was proposed. Stephaochratidin A (1) exhibited significant ferroptosis inhibitory activity with the EC50 value of 15.4 µM by downregulating HMOX-1 expression and lipid peroxidation.

Inhibitory Effect of Ginsenoside Rg1 on Vascular Smooth Muscle Cell Proliferation Induced by PDGF-BB Is Involved in Nitric Oxide Formation.

Ginsenoside Rg1 (Rg1) has been reported to suppress the proliferation of vascular smooth muscle cells (VSMCs). This study aimed to observe the role of nitric oxide (NO) in Rg1-antiproliferative effect. VSMCs from the thoracic aorta of SD rats were cultured by tissue explant method, and the effect of Rg1 (20 mg·L(-1), 60 mg·L(-1), and 180 mg·L(-1)) on platelet-derived growth factor-BB (PDGF-BB)-induced proliferation was evaluated by MTT assay. The cell cycle was analyzed by flow cytometry. For probing the mechanisms, the content of NO in supernatant and cGMP level in VSMCs was measured by nitric oxide kit and cGMP radio-immunity kit, respectively; the expressions of protooncogene c-fos and endothelial NO synthase (eNOS) mRNA in the VSMCs were detected by real-time RT-PCR; the intracellular free calcium concentration ([Ca2(+)](i)) was detected with Fura-2/AM-loaded VSMCs. Comparing with that in normal group, Rg1 180 mg·L(-1) did not change the absorbance of MTT and cell percent of G(0)/G(1), G(2)/M, and S phase in normal cells (P > 0.05). Contrarily, PDGF-BB could increase the absorbance of MTT (P < 0.01) and the percent of the S phase cells but decrease the G(0)/G(1) phase cell percent in the cell cycle, accompanied with an upregulating c-fos mRNA expression (P < 0.01), which was reversed by additions of Rg1(20 mg·L(-1), 60 mg·L(-1), and 180 mg·L(-1)). Rg1 administration could also significantly increase the NO content in supernatant and the cGMP level in VSMCs, as well as the eNOS mRNA expression in the cells, in comparison of that in the group treated with PDGF-BB alone (P < 0.01). Furthermore, Rg1 caused a further increase in the elevated [Ca(2+)](i) induced by PDGF-BB. It was concluded that Rg1 could inhibit the VSMC proliferation induced by PDGF-BB through restricting the G(0)/G(1) phase to S-phase progression in cell cycle. The mechanisms may be related to the upregulation of eNOS mRNA and the increase of the formation of NO and cGMP.

Current status of immunotherapy for non-small cell lung cancer.

Nowadays, lung cancer is still the deadliest oncological disease in the world. Among them, non-small cell lung cancer (NSCLC) accounts for 80%∼85% of all lung cancers, and its 5-year survival rate is less than 15%, making the situation critical. In the past decades, despite some clinical advances in conventional treatments, the overall survival rate of NSCLC is still not optimistic due to its unique physiological conditions and the frequent occurrence of tumor escape. In recent years, immunotherapy has become a new hot spot in lung cancer research, including antibody therapy and cell therapy, which have been developed and utilized one after another, especially immune checkpoint inhibitor (ICI). These approaches have effectively improved the overall survival rate and objective response rate of NSCLC patients by enhancing the immune capacity of the body and targeting tumor cells more effectively, which is more specific and less toxic compared with conventional chemotherapy, and providing more strategies for NSCLC treatment. In this paper, we reviewed the relevant targets, clinical progress and adverse reaction in monoclonal antibodies, antibody-drug conjugates, ICI, bispecific antibodies, T-cell receptor engineered T cell therapy (TCR-T), Chimeric antigen receptor T-cell immunotherapy (CAR-T), and also report on their combination therapy from the immune-related background to provide better NSCLC treatment and prospective.

Dendrobium nobile Lindl. Alkaloids Ameliorate Cognitive Dysfunction in Senescence Accelerated SAMP8 Mice by Decreasing Amyloid-ß Aggregation and Enhancing Autophagy Activity.

BACKGROUND: Dendrobium nobile is a well-known traditional Chinese herbal medicine used for age-related diseases. Dendrobium nobile Lindl. alkaloid (DNLA) is the active ingredient to improve learning and memory deficits in laboratory animals. OBJECTIVE: The aim of the present study was to examine the anti-aging effects of long-term administration of DNLA and metformin during the aging process in senescence-accelerated mouse-prone 8 (SAMP8) mice. METHODS: SAMP8 mice were orally given DNLA (20 and 40 mg/kg) or metformin (80 mg/kg) starting at 6 months of age until 12 months of age. Age-matched SAMR1 mice were used as controls. DNLA and metformin treatments ameliorated behavioral deficits of 12-month-old SAMP8 mice, as determined by Rotarod, Y-maze, and Open-field tests. RESULTS: DNLA and metformin treatments prevented brain atrophy and improved morphological changes in the hippocampus and cortex, as evidenced by Nissl and H&E staining for neuron damage and loss, and by SA-ß-gal staining for aging cells. DNLA and metformin treatments decreased amyloid-ß1-42, AßPP, PS1, and BACE1, while increasing IDE and neprilysin for Aß clearance. Furthermore, DNLA and metformin enhanced autophagy activity by increasing LC3-II, Beclin1, and Klotho, and by decreasing p62 in the hippocampus and cortex. CONCLUSION: The beneficial effects of DNLA were comparable to metformin in protecting against aging-related cognitive deficits, neuron aging, damage, and loss in SAMP8 mice. The mechanisms could be attributed to increased Aß clearance, activation of autophagy activity, and upregulation of Klotho.

Function and dysfunction of plasma cells in intestine.

As the main player in humoral immunity, antibodies play indispensable roles in the body's immune system. Plasma cells (PCs), as antibody factories, are important contributors to humoral immunity. PCs, recognized by their unique marker CD138, are always discovered in the medullary cords of spleen and lymph nodes and in bone marrow and mucosal lymphoid tissue. This article will review the origin and differentiation of PCs, characteristics of short- and long-lived PCs, and the secretion of antibodies, such as IgA, IgM, and IgG. PCs play a crucial role in the maintenance of intestinal homeostasis using immunomodulation though complex mechanisms. Clearly, PCs play functional roles in maintaining intestinal health, but more details are needed to fully understand all the other effects of intestinal PCs.

Functional macrophages and gastrointestinal disorders.

Macrophages (MΦ) differentiate from blood monocytes and participate in innate and adaptive immunity. Because of their abilities to recognize pathogens and activate bactericidal activities, MΦ are always discovered at the site of immune defense. MΦ in the intestine are unique, such that in the healthy intestine, they possess complex mechanisms to protect the gut from inflammation. In these complex mechanisms, they produce anti-inflammatory cytokines, such as interleukin-10 and transforming growth factor-ß, and inhibit the inflammatory pathways mediated by Toll-like receptors. It has been demonstrated that resident MΦ play a crucial role in maintaining intestinal homeostasis, and they can be recognized by their unique markers. Nonetheless, in the inflamed intestine, the function of MΦ will change because of environmental variation, which may be one of the mechanisms of inflammatory bowel disease (IBD). We provide further explanation about these mechanisms in our review. In addition, we review recent discoveries that MΦ may be involved in the development of gastrointestinal tumors. We will highlight the possible therapeutic targets for the management of IBD and gastrointestinal tumors, and we also discuss why more details are needed to fully understand all other effects of intestinal MΦ.

Dendrobium nobile Lindl. Alkaloids Decreases the Level of Intracellular ß-Amyloid by Improving Impaired Autolysosomal Proteolysis in APP/PS1 Mice.

As the major degradation pathway for long-lived proteins and organelles, macroautophagy is a decisive factor for the survival and longevity of cells. The existing evidence indicates that the disruption of substrate proteolysis in autolysosomes is the main mechanism underlying autophagy failure in Alzheimer's disease (AD). Thus, the restoration of normal lysosomal proteolysis and autophagy efficiency is a novel therapeutic strategy in the treatment of AD. In this study, 9-month-old APPswe/PS1ΔE9 transgenic (APP/PS1) mice were administered Dendrobium nobile Lindl. alkaloids (DNLA, 40 and 80 mg/kg) or Metformin (80 mg/kg), and age-matched wild-type mice were administered an isovolumic vehicle orally once a day for 4 months. The results demonstrated that DNLA significantly improved learning and memory function in APP/PS1 transgenic mice in the Morris water maze. Furthermore, DNLA could increase the expression of the v-ATPase A1 subunit to facilitate lysosomal acidification, prompt the dissociation of the cation independent-mannose-phosphate receptor from cathepsin (cat) D, promote the proteolytic maturation of cat D, increase the degradation of accumulated autophagic vacuoles (AVs) and ß-amyloid (Aß) contained in the AVs, and alleviate neuronal and synaptic injury. These findings demonstrate that DNLA improves learning and memory function in APP/PS1 mice, and the mechanisms appear to be due to the promotion of intracellular Aß degradation by increasing the protein level of v-ATPase A1 and then improving autolysosomal acidification and proteolysis.

Dendrobium nobile Lindl alkaloid, a novel autophagy inducer, protects against axonal degeneration induced by Aß25-35 in hippocampus neurons in vitro.

AIMS: Axonal degeneration is a pathological symbol in the early stage of Alzheimer's disease (AD), which can be triggered by amyloid-ß (Aß) peptide deposition. Growing evidence indicates that deficit of autophagy eventually leads to the axonal degeneration. Our previous studies have shown that Dendrobium nobile Lindl alkaloid (DNLA) had protective effect on neuron impairment in vivo and in vitro; however, the underlying mechanisms is still unclear. METHODS: We exposed cultured hippocampus neurons to Aß25-35 to investigate the effect of DNLA in vitro. Axonal degeneration was evaluated by immunofluorescence staining and MTT assay. Neurons overexpressing GFP-LC3B were used to measure the formation of autophagosome. Autophagosome-lysosome fusion, the lysosomal pH, and cathepsin activity were assessed to reflect autophagy process. Proteins of interest were analyzed by Western blot. RESULTS: DNLA pretreatment significantly inhibited axonal degeneration induced by Aß25-35 peptide in vitro. Further studies revealed DNLA treatment increased autophagic flux through promoting formation and degradation of autophagosome in hippocampus neurons. Moreover, enhancement of autophagic flux was responsible for the protective effects of DNLA on axonal degeneration. CONCLUSIONS: DNLA prevents Aß25-35 -induced axonal degeneration via activation of autophagy process and could be a novel therapeutic target.

Dendrobium alkaloids prevent Aß25-35-induced neuronal and synaptic loss via promoting neurotrophic factors expression in mice.

BACKGROUND: Neuronal and synaptic loss is the most important risk factor for cognitive impairment. Inhibiting neuronal apoptosis and preventing synaptic loss are promising therapeutic approaches for Alzheimer's disease (AD). In this study, we investigate the protective effects of Dendrobium alkaloids (DNLA), a Chinese medicinal herb extract, on ß-amyloid peptide segment 25-35 (Aß25-35)-induced neuron and synaptic loss in mice. METHOD: Aß25-35(10 µg) was injected into the bilateral ventricles of male mice followed by an oral administration of DNLA (40 mg/kg) for 19 days. The Morris water maze was used for evaluating the ability of spatial learning and memory function of mice. The morphological changes were examined via H&E staining and Nissl staining. TUNEL staining was used to check the neuronal apoptosis. The ultrastructure changes of neurons were observed under electron microscope. Western blot was used to evaluate the protein expression levels of ciliary neurotrophic factor (CNTF), glial cell line-derived neurotrophic factor (GDNF), and brain-derived neurotrophic factor (BDNF) in the hippocampus and cortex. RESULTS: DNLA significantly attenuated Aß25-35-induced spatial learning and memory impairments in mice. DNLA prevented Aß25-35-induced neuronal loss in the hippocampus and cortex, increased the number of Nissl bodies, improved the ultrastructural injury of neurons and increased the number of synapses in neurons. Furthermore, DNLA increased the protein expression of neurotrophic factors BDNF, CNTF and GDNF in the hippocampus and cortex. CONCLUSIONS: DNLA can prevent neuronal apoptosis and synaptic loss. This effect is mediated at least in part via increasing the expression of BDNF, GDNF and CNTF in the hippocampus and cortex; improving Aß-induced spatial learning and memory impairment in mice.

Icariin Inhibits Pulmonary Hypertension Induced by Monocrotaline through Enhancement of NO/cGMP Signaling Pathway in Rats.

It has been reported that icariin (ICA) increased contents of nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) by improving expression of endothelial nitric oxide synthase (eNOS) and inhibition of phosphodiesterase type 5 (PDE5). In addition, dysfunction of the NO/cGMP pathway may play a crucial role in the pathogenesis of pulmonary hypertension (PH). In this study, the potential protective effects of ICA on PH induced by monocrotaline (MCT, 50 mg/kg) singly subcutaneous injection were investigated and the possible mechanisms involved in NO/cGMP pathway were explored in male Sprague Dawley rats. The results showed that ICA (20, 40, and 80 mg/kg/d) treatment by intragastric administration could significantly ameliorate PH and upregulate the expression of eNOS gene and downregulate the expression of PDE5 gene in MCT-treated rats. Both ICA (40 mg/kg/d) and L-arginine (200 mg/kg/d), a precursor of NO as positive control, notably increased the contents of NO and cGMP in lung tissue homogenate, which were inversed by treatment with (N) G-nitro-L-arginine-methyl ester (L-NAME), a NOS inhibitor, and L-NAME-treatment could also inhibit the protective effects of ICA (40 mg/kg/d) on mean pulmonary artery pressure and artery remodeling and tends to inhibit right ventricle hypertrophy index. In summary, ICA is effective in protecting against MCT-induced PH in rats through enhancement of NO/cGMP signaling pathway in rats.

Effect of entacapone on colon motility and ion transport in a rat model of Parkinson's disease.

AIM: To study the effects of entacapone, a catechol-O-methyltransferase inhibitor, on colon motility and electrolyte transport in Parkinson's disease (PD) rats. METHODS: Distribution and expression of catechol-O-methyltransferase (COMT) were measured by immunohistochemistry and Western blotting methods. The colonic smooth muscle motility was examined in vitro by means of a muscle motility recording device. The mucosal electrolyte transport of PD rats was examined by using a short-circuit current (ISC ) technique and scanning ion-selective electrode technique (SIET). Intracellular detection of cAMP and cGMP was accomplished by radioimmunoassay testing. RESULTS: COMT was expressed in the colons of both normal and PD rats, mainly on the apical membranes of villi and crypts in the colon. Compared to normal controls, PD rats expressed less COMT. The COMT inhibitor entacapone inhibited contraction of the PD rat longitudinal muscle in a dose-dependent manner. The ß2 adrenoceptor antagonist ICI-118,551 blocked this inhibitory effect by approximately 67% (P < 0.01). Entacapone increased mucosal ISC in the colon of rats with PD. This induction was significantly inhibited by apical application of Cl(-) channel blocker diphenylamine-2, 2'-dicarboxylic acid, basolateral application of Na(+)-K(+)-2Cl(-)co-transporter antagonist bumetanide, elimination of Cl(-) from the extracellular fluid, as well as pretreatment using adenylate cyclase inhibitor MDL12330A. As an inhibitor of prostaglandin synthetase, indomethacin can inhibit entacapone-induced ISC by 45% (P < 0.01). When SIET was applied to measure Cl(-) flux changes, this provided similar results. Entacapone significantly increased intracellular cAMP content in the colonic mucosa, which was greatly inhibited by indomethacin. CONCLUSION: COMT expression exists in rat colons. The ß2 adrenoceptor is involved in the entacapone-induced inhibition of colon motility. Entacapone induces cAMP-dependent Cl(-) secretion in the PD rat.

Significance of changes of gastrointestinal peptides in blood and ileum of experimental spleen deficiency rats.

AIM: To explore the mechanism of spleen deficiency (SD) by studying the relationship of gastro-intestinal peptides level and ileal electro-mechanical activity of SD rats and cold restrain rats. METHODS: (1) spleen deficiency (SD) model was established by feeding Houpou:Zhishi: Dahuang in the ratio of 3:3:2, 3 ml/time, for 42 days. (2) The cold restrain stress model: Animals were restrained on grille and placed in a cool water at 18 degrees for 3 h. (3) Substance P (SP) and vasoactive intestinal peptide (VIP) levels in all layers of initial part of ileum and blood in rats were measured by radioimmunoassays (RIA) while changes of electric activity and motility in ileum of rats were recorded with electrode and strain gauge. RESULTS: SP levels in ileum and blood of experimental SD rats were significantly higher than that of the control groups (9.89+/-5.65 vs 1.22+/-1.18, P<0.005, in ileum; 22.7+/-3.95 vs 6.60+/-1.47, P<0.001, in blood) while the VIP levels of the SD rats were significantly lower than that of the controls (3.50+/-2.01 vs 9.10+/-4.91, P<0.05, in ileum; 229.8+/-62.4 vs 560.4+/-151.3, P<0.001, in blood). As compared with the controls, the average frequency of slow electric waves (21.3+/-0.96 vs 18.2+/-2.28, P<0.05) and motility (21.5+/-0.58 vs 18+/-2.65, P<0.005) of SD rats increased obviously and the frequency of fast waves of SD rat also increased. In spontaneous recovery cases, SP levels recovered significantly (compared with the SD groups, 2.99+/-0.62 vs 9.89+/-5.65, P<0.001, in ileum; 14.4+/-4.22 vs 22.7+/-3.95, P<0.001, in blood) but did not drop to normal. After the SD rats treated with Chinese herbs (Jiawei Sijun zi Tang), SP improved (compared with SD cases, 2.20+/-1.25 vs 9.89+/-5.65, (P<0.001), in ileum; 10.7+/-1.88 vs 22.7+/-3.95, (P<0.001), in blood) and VIP in blood also improved (compared with SD rats, 485.7+/-229.0 vs 229.8+/-62.4, P<0.01) while the amplitude of motility decreased apparently (compared with the SD rats, 0.64+/-0.096 vs 0.89+/-0.15, P<0.01). The ileal SP levels of cool stress didn't change while the ileal VIP levels of cool stress became significantly lower than that of the control groups (2.87+/-0.87 vs 9.10+/-4.91, P<0.01). The blood SP levels of cool stress were significantly higher (15.60+/-1.83 vs 6.60+/-1.47, P<0.001) whereas the blood VIP levels of cool stress were significantly lower than that of the control group (153.4+/-70.46 vs 560.4+/-151.30, P<0.001). CONCLUSION: Changes of SP and VIP levels in initial part of ileum and blood of SD rats and cool stress rats may be closely related to the gastrointestinal motility disorders presented in SD and cool stress rats. the Chinese herbs (Jiawei Sijun zi Tang) currently used have partially therapeutic effect.

Dopamine D1 receptors mediate dopamine-induced duodenal epithelial ion transport in rats.

Dopamine (DA) is synthesized in gastrointestinal epithelial cells and performs important regulatory effects on the duodenal mucosa. However, the underlying mechanism remains largely unknown. The present study investigated the effect of DA on the duodenal epithelial ion transport in rats by means of short-circuit current (ISC), real-time pH titration, enzyme-linked immunosorbent assay, and immunohistochemistry. The results indicate that basolateral, but not apical, application of DA induced a concentration-dependent ISC downward deflection with an apparent IC50 of 5.34 µmol/L. Basolateral application of dopaminergic receptor D1 (D1) antagonist, SCH-23390, inhibited DA-induced change in ISC (△ISC) in a dose-dependent manner. D1 agonist, SKF38393, mimicked the effect of DA on the ISC. The clear immunoreactivity of D1 subtype D5 (D1b) was at the both apical and basolatoral sides of Brunner's glands and intestinal crypts. Basolateral pretreatment with adenylate cyclase inhibitor, MDL12330A, significantly inhibited DA- and forskolin-induced △ISC. DA and SKF38393 increased the level of intracellular cyclic adenosine monophosphate (cAMP) from 1.55 ± 0.11 to 2.07 ± 0.11 and 5.91 ± 0.25 pmol/L·mg(-1), respectively. Furthermore, the serosal DA-induced △ISC was remarkably inhibited by apical administration of K(+) channel blockers, Ba(2+) and tetraethylammonium, but not by Cl(-) channel blockers. Serosal DA and D1 agonist did not affect duodenal HCO3(-) secretion. In conclusion, the present results demonstrate that serosal DA is able to promote rat duodenal epithelial K(+) secretion, not HCO3(-) secretion through D1-mediated and cAMP-dependent pathway. The study provides a new insight in the modulation of DA on the ion transport of duodenal epithelia in rats.

Colonic submucosal 5-HT(3) receptor-mediated somatostatin-dependent secretoinhibitory pathway is suppressed in water-immersion restraint stressed rats.

We have demonstrated that the activation of 5-hydroxytryptamine (5-HT) receptor 3 in the submucosal plexus suppresses 5-HT-induced colonic ion secretion by increasing submucosal somatostatin release. A number of psychological and physical stresses have impacts on the intestinal mucosal functions, including secretion and the epithelial barrier. Whether the 5-HT(3) receptor-mediated somatostatin-dependent secretoinhibitory pathway in the rat distal colon is involved in the stress process is still unknown. The present study aims to investigate the effect of the water-immersion restraint stress on this inhibitory pathway and its underlying mechanisms. Mucosa/submucosa preparations from the rat distal colon were mounted in the Ussing chambers for the measurement of short-circuit current (I(SC)). Real-time PCR and western blot were performed to study the expression of the 5-HT(3) receptor, 5-HT(4) receptor, and somatostatin receptor 2. Radioimmunoassay was used to measure somatostatin release. After 2h of water-immersion restraint stress, the membrane resistance (Rte) of rat mucosa/submucosa preparations was significantly decreased, but the baseline I(SC) and 5-HT-induced I(SC) responses were significantly increased. The protein expression of the submucosal 5-HT(3) receptors and mucosal somatostatin receptor 2 were down-regulated, and the 5-HT-induced somatostatin release from the mucosa/submucosa preparations was significantly reduced in the stress group. Taken together, these results suggest that the 5-HT(3) receptor-mediated somatostatin-dependent secretoinhibitory pathway is suppressed in the water-immersion restraint stressed rats, which may contribute to the acute stress-induced increase in colonic secretion.

Involvement of endogenous prostaglandin in emodin-evoked rat colonic anion secretion.

It has been reported that emodin is able to promote gastrointestinal motility and stimulate large intestinal water secretion; however, the mechanism is still not clear. The aim of the present study is to examine the effects of emodin on the rat colonic transepithelial ion transport and the underlying mechanism. The study was carried out by means of the short circuit current (I(SC)) recording. Basolateral application of emodin induced a concentration-dependent I(SC) increase, and the EC(50) was 76.0 micromol/l. Pretreatment with epithelial Na(+) channel blocker, amiloride (10 micromol/l), did not affect the I(SC) responses elicited by emodin, but removal of extracellular Cl(-) or apical pretreatment with Cl(-) channel blocker, glibenclamide (1 mmol/l) inhibited emodin-elicited I(SC) responses by 76.3% and 83.8% respectively. Inhibiting basolateral Na(+)-K(+)-2Cl(-) cotransporter (NKCC) with bumetanide (100 micromol/l) decreased emodin-induced I(SC) from 118.1+/-6.7 microA/cm(2) to 16.7+/-2.0 microA/cm(2), which was reduced by 85.9%. Basolateral pretreatment with neuronal Na(+) channel blocker tetrodotoxin (TTX) (1 micromol/l) did not affect emodin-induced I(SC) increase, but pretreatment with indomethacin (10 micromol/l) alone or with both TTX and indomethacin significantly decreased emodin-induced I(SC) increase by 88.4 and 81.2%, respectively. The present study demonstrated that emodin was able to stimulate rat colonic epithelial Cl(-) secretion, which was predominantly mediated by endogenous prostaglandin release.

Self-assembling biomaterials: liquid crystal phases of cholesteryl oligo(L-lactic acid) and their interactions with cells.

We report here on the synthesis and characterization of a series of self-assembling biomaterials with molecular features designed to interact with cells and scaffolds for tissue regeneration. The molecules of these materials contain cholesteryl moieties, which have universal affinity for cell membranes, and short chains of lactic acid, a common component of biodegradable tissue engineering matrices. The materials were synthesized in good yields with low polydispersities in the range of 1.05-1.15, and their characterization was carried out by small-angle x-ray diffraction, transmission electron microscopy, electron diffraction, differential scanning calorimetry, and atomic force microscopy. These molecular materials form layered structures that can be described as smectic phases and can also order into single-crystal stacks with an orthorhombic unit cell. Their layer spacings range from 58 to 99 A, corresponding to bilayers of oligomers with an average of 10 and 37 lactic acid residues, respectively. The self-organized layered structures were found to promote improved fibroblast adhesion and spreading, although the specific mechanism for this observed response remains unknown. The ability of self-assembling materials to present ordered and periodic bulk structures to cells could be a useful strategy in tissue engineering.