[Research advances of Zaoren Anshen prescription preparations].

Zaoren Anshen prescription preparations(ZRASs), which are prepared from three traditional Chinese herb medicines, namely fried Zizyphi Spinosae Semen, Salvia Miltiorrhizae Radix et Rhizoma and vinegar-processed Schisandrae Chinensis Fructus, are a series of proprietary Chinese medicines for the treatment of insomnia, amnesia and dizzy in clinic. In recent years, pharmacodynamic effect, chemical constituents and quality control of ZRASs had been extensively studied for the purpose of ensuring their safety, efficacy and stability, and a great progress had been made. However, there is no review of the research advance of ZRASs up to date. The present review summarized the research advance of ZRASs in quality control standards, chemical constituents, pharmacodynamic effects, and chemical analysis for the first time, with the aim to provide a reference for further studies on the effective constituents and quality control of ZRASs.

BMAL1 Disrupted Intrinsic Diurnal Oscillation in Rat Cerebrovascular Contractility of Simulated Microgravity Rats by Altering Circadian Regulation of miR-103/CaV1.2 Signal Pathway.

The functional and structural adaptations in cerebral arteries could be one of the fundamental causes in the occurrence of orthostatic intolerance after space flight. In addition, emerging studies have found that many cardiovascular functions exhibit circadian rhythm. Several lines of evidence suggest that space flight might increase an astronaut's cardiovascular risks by disrupting circadian rhythm. However, it remains unknown whether microgravity disrupts the diurnal variation in vascular contractility and whether microgravity impacts on circadian clock system. Sprague-Dawley rats were subjected to 28-day hindlimb-unweighting to simulate the effects of microgravity on vasculature. Cerebrovascular contractility was estimated by investigating vasoconstrictor responsiveness and myogenic tone. The circadian regulation of CaV1.2 channel was determined by recording whole-cell currents, evaluating protein and mRNA expressions. Then the candidate miRNA in relation with Ca2+ signal was screened. Lastly, the underlying pathway involved in circadian regulation of cerebrovascular contractility was determined. The major findings of this study are: (1) The clock gene BMAL1 could induce the expression of miR-103, and in turn modulate the circadian regulation of CaV1.2 channel in rat cerebral arteries at post-transcriptional level; and (2) simulated microgravity disrupted intrinsic diurnal oscillation in rat cerebrovascular contractility by altering circadian regulation of BMAL1/miR-103/CaV1.2 signal pathway.

Salidroside improved cerebrovascular vasodilation in streptozotocin-induced diabetic rats through restoring the function of BKCa channel in smooth muscle cells.

Vessel disease is a kind of severe complication in diabetic patients. However, few pharmacologic agents can directly recover diabetic vascular function. Salidroside (SAL), a major ingredient from Rhodiola rosea, has been found to have an obvious hypoglycemic effect and a beneficial protection on vascular function in diabetes. However, whether SAL is a suitable treatment for diabetes has not so far been evaluated and the underlying mechanisms remain unknown. The present work aims to (1) investigate the potential effects of SAL on cerebrovascular relaxation in streptozotocin-induced diabetic rats or when exposed to acute hyperglycemia condition and (2) examine whether function of the BKCa channel is involved in SAL treatment for diabetic vascular relaxation. Our results indicate that chronic administration of 100 mg/kg/day SAL not only improves cerebrovascular relaxation but also increases BKCa ß1-subunit expressions at both protein and mRNA levels and enhances BKCa whole-cell and single-channel activities in cerebral VSMCs of diabetic rats. Correspondingly, acute application of 100 µM SAL induces cerebrovascular relaxation by activation of the BKCa channel. Furthermore, SAL activated the BKCa channel mainly through acting on the ß1-subunit in HEK293 cells transfected with hSloα+ß1 constructs. We concluded that SAL improved vasodilation in diabetic rats through restoring the function of the BKCa-ß1 subunit in cerebrovascular smooth muscle cells, which may be the underlying mechanism responsible for the vascular protection of SAL in diabetes.

Berberine alleviates the cerebrovascular contractility in streptozotocin-induced diabetic rats through modulation of intracellular Ca²âº handling in smooth muscle cells.

BACKGROUND: Vascular dysfunction is a distinctive phenotype in diabetes mellitus. Current treatments mostly focus on the tight glycemic control and few of these treatments have been designed to directly recover the vascular dysfunction in diabetes. As a classical natural medicine, berberine has been explored as a possible therapy for DM. In addition, it is reported that berberine has an extra-protective effect in diabetic vascular dysfunction. However, little is known whether the berberine treatment could ameliorate the smooth muscle contractility independent of a functional endothelium under hyperglycemia. Furthermore, it remains unknown whether berberine affects the arterial contractility by regulating the intracellular Ca(2+) handling in vascular smooth cells (VSMCs) under hyperglycemia. METHODS: Sprague-Dawley rats were used to establish the diabetic model with a high-fat diet plus injections of streptozotocin (STZ). Berberine (50, 100, and 200 mg/kg/day) were intragastrically administered to control and diabetic rats for 8 weeks since the injection of STZ. The intracellular Ca(2+) handling of isolated cerebral VSMCs was investigated by recording the whole-cell L-type Ca(2+) channel (CaL) currents, assessing the protein expressions of CaL channel, and measuring the intracellular Ca(2+) in response to caffeine. Our results showed that chronic administration of 100 mg/kg/day berberine not only reduced glucose levels, but also inhibited the augmented contractile function of cerebral artery to KCl and 5-hydroxytryptamine (5-HT) in diabetic rats. Furthermore, chronic administration of 100 mg/kg/day berberine significantly inhibited the CaL channel current densities, reduced the α1C-subunit expressions of CaL channel, decreased the resting intracellular Ca(2+) ([Ca(2+)]i) level, and suppressed the Ca(2+) releases from RyRs in cerebral VSMCs isolated from diabetic rats. Correspondingly, acute application of 10 µM berberine could directly inhibit the hyperglycemia-induced CaL currents and suppress the hyperglycemia-induced Ca(2+) releases from RyRs in cerebral VSMCs isolated from normal control rats. CONCLUSIONS: Our study indicated that berberine alleviated the cerebral arterial contractility in the rat model of streptozotocin-induced diabetes via regulating the intracellular Ca(2+) handling of smooth muscle cells.

Simulated microgravity promotes monocyte adhesion to rat aortic endothelium via nuclear factor-κB activation.

Microgravity-induced vascular remodelling may play an important role in post-spaceflight orthostatic intolerance. In this study, we aimed to investigate the effects of simulated microgravity on monocyte adhesion to aortic endothelium in hindlimb unweighted rats and to elucidate the underlying mechanisms associated with this event. Sprague-Dawley rats were subjected to 4-week hindlimb unweighting to simulate microgravity. The recruitment of monocytes to the abdominal aorta was investigated by en face immunofluorescence staining and monocyte binding assays. The expression of the adhesion molecules E-selectin and vascular cell adhesion molecule-1 as well as the cytokine monocyte chemoattractant protein (MCP)-1 was evaluated by immunohistochemical staining, western blot, and quantitative reverse transcription polymerase chain reaction analyses. Additionally, nuclear factor-κB (NF-κB) activation and the messenger RNA expression levels of E-selectin, vascular cell adhesion molecule-1, and MCP-1 were assessed with the administration of an NF-κB inhibitor, pyrrolidine dithiocarbamate. Results showed that simulated microgravity significantly increased monocyte recruitment to the aortic endothelium, protein expression of E-selectin and MCP-1, and NF-κB activation in the abdominal aorta of rats. Pyrrolidine dithiocarbamate treatment not only significantly inhibited NF-κB activity but also reduced the messenger RNA levels of E-selectin, vascular cell adhesion molecule-1, and MCP-1 as well as monocyte recruitment in the abdominal aorta of hindlimb unweighted rats. These results suggest that simulated microgravity increases monocyte adhesion to rat aortic endothelium via the NF-κB-mediated expression of the adhesion molecule E-selectin and the cytokine MCP-1. Therefore, an NF-κB-mediated inflammatory response may be one of the cellular mechanisms responsible for arterial remodelling during exposure to microgravity.

Simulated microgravity induces an inflammatory response in the common carotid artery of rats.

Post-spaceflight orthostatic intolerance is one of the most important adverse effects after exposure to space microgravity, and there are still no effective countermeasures. It has been considered that arterial remodeling may play an important role in the occurrence of post-spaceflight orthostatic intolerance, but the cellular mechanisms remain unknown. In this study, we investigated whether an inflammatory response exists in the common carotid artery of rats exposed to simulated microgravity. For this, Sprague-Dawley rats were subjected to 4 weeks of hindlimb unweighting to simulate microgravity. The expression levels of the adhesion molecules E-selectin and vascular cell adhesion molecule-1 (VCAM-1), and the cytokine monocyte chemoattractant protein-1 (MCP-1) in the common carotid artery of simulated microgravity rats were evaluated by immunohistochemical staining, quantitative RT-PCR, and Western blot analyses. The recruitment of monocytes in the common carotid artery of rats exposed to simulated microgravity was investigated by en face immunofluorescence staining and monocyte binding assays. Our results provided convincing evidence that there is an inflammatory response in the common carotid artery of rats exposed to simulated microgravity. Our work suggests that the inflammatory response may be a novel cellular mechanism that is responsible for the arterial remodeling that occurs during exposure to microgravity.

[Metabolites of long-time preserved-acutely isolated rat cardiomyocytes affect L-type Ca(2+) channel current].

The variability of peak current of L-type calcium channel (I(Ca,L)) shows an increase in cardiomyocytes after 6 h of preservation when the acutely isolated cardiomyocytes are preserved in a small volume buffer solution. The mechanism of the increased variability of I(Ca,L) is not clear. In order to obtain more accurately and stably experimental data of I(Ca,L), the aim of this study was to observe the pH changes of preservation buffer solution with acutely isolated rat cardiomyocytes, and the effects of pH changes on the shape of cardiomyocytes, the function of mitochondria and the gating property of L-type calcium channel. The results indicated that the pH was kept stable in 100 mL buffer solution, but was decreased from 7.20 to 6.95 in 20 mL buffer solution during 10 h of cardiomyocyte preservation. Therefore, 100 mL or 20 mL preservation solution was used as a normal control or acidotic group, respectively. The ratio of abnormal to normal rod-shaped cardiomyocytes increased in the acidotic group after 6 h of preservation. The acidosis induced a reduction in mitochondrial membrane potential indicated by JC-1 fluorescent probe after 8 h of cardiomyocyte preservation. The acidosis also shifted the autofluorescence of NADPH from blue to green after 8 h of cardiomyocyte preservation. The above changes in mitochondrial function induced a significant decrease in the peak I(Ca,L) and a shift in the clamped voltage at peak I(Ca,L) from +10 mV to 0 mV, after 10 h of cardiomyocyte preservation. These results suggest that the best way to preserve acutely isolated cardiomyocytes is to use a larger volume buffer system. In order to get stable peak I(Ca,L), we need to not only select a normal shape of cardiomyocyte at a bright field but also a blue fluorescent myocyte at an ultraviolet excitation.

High glucose alters apoptosis and proliferation in HEK293 cells by inhibition of cloned BK Ca channel.

It has been reported that diabetic vascular dysfunction is associated with impaired function of large conductance Ca(2+) -activated K(+) (BK(Ca) ) channels. However, it is unclear whether impaired BK(Ca) channel directly participates in regulating diabetic vascular remodeling by altering cell growth in response to hyperglycemia. In the present study, we investigated the specific role of BK(Ca) channel in controlling apoptosis and proliferation under high glucose concentration (25 mM). The cDNA encoding the α+ß1 subunit of BK(Ca) channel, hSloα+ß1, was transiently transfected into human embryonic kidney 293 (HEK293) cells. Cloned BK(Ca) currents were recorded by both whole-cell and cell-attached patch clamp techniques. Cell apoptosis was assessed with immunocytochemistry and analysis of fragmented DNA by agarose gel electrophoresis. Cell proliferation was investigated by flow cytometry assays, MTT test, and immunocytochemistry. In addition, the expression of anti-apoptotic protein Bcl-2, intracellular Ca(2+) , and mitochondrial membrane potential (Δψm) were also examined to investigate the possible mechanisms. Our results indicate that inhibition of cloned BK(Ca) channels might be responsible for hyperglycemia-altered apoptosis and proliferation in HEK-hSloα+ß1 cells. However, activation of BK(Ca) channel by NS1619 or Tamoxifen significantly induced apoptosis and suppressed proliferation in HEK-hSloα+ß1 cells under hyperglycemia condition. When rat cerebral smooth muscle cells were cultured in hyperglycemia, similar findings were observed. Moreover, the possible mechanisms underlying the activation of BK(Ca) channel were associated with decreased expression of Bcl-2, elevation of intracellular Ca(2+) , and a concomitant depolarization of Δψm in HEK-hSloα+ß1 cells. In conclusion, cloned BK(Ca) channel directly regulated apoptosis and proliferation of HEK293 cell under hyperglycemia condition.

Mitochondrial Oxidative Stress Enhances Vasoconstriction by Altering Calcium Homeostasis in Cerebrovascular Smooth Muscle Cells under Simulated Microgravity.

OBJECTIVE: Exposure to microgravity results in postflight cardiovascular deconditioning in astronauts. Vascular oxidative stress injury and mitochondrial dysfunction have been reported during this process. To elucidate the mechanism for this condition, we investigated whether mitochondrial oxidative stress regulates calcium homeostasis and vasoconstriction in hindlimb unweighted (HU) rat cerebral arteries. METHODS: Three-week HU was used to simulate microgravity in rats. The contractile responses to vasoconstrictors, mitochondrial fission/fusion, Ca 2+ distribution, inositol 1,4,5-trisphosphate receptor (IP 3R) abundance, and the activities of voltage-gated K + channels (K V) and Ca 2+-activated K + channels (BK Ca) were examined in rat cerebral vascular smooth muscle cells (VSMCs). RESULTS: An increase of cytoplasmic Ca 2+ and a decrease of mitochondrial/sarcoplasmic reticulum (SR) Ca 2+ were observed in HU rat cerebral VSMCs. The abundance of fusion proteins (mitofusin 1/2 [MFN1/2]) and fission proteins (dynamin-related protein 1 [DRP1] and fission-mitochondrial 1 [FIS1]) was significantly downregulated and upregulated, respectively in HU rat cerebral VSMCs. The cerebrovascular contractile responses to vasoconstrictors were enhanced in HU rats compared to control rats, and IP 3R protein/mRNA levels were significantly upregulated. The current densities and open probabilities of K V and BK Ca decreased and increased, respectively. Treatment with the mitochondrial-targeted antioxidant mitoTEMPO attenuated mitochondrial fission by upregulating MFN1/2 and downregulating DRP1/FIS1. It also decreased IP 3R expression levels and restored the activities of the K V and BK Ca channels. MitoTEMPO restored the Ca 2+ distribution in VSMCs and attenuated the enhanced vasoconstriction in HU rat cerebral arteries. CONCLUSION: The present results suggest that mitochondrial oxidative stress enhances cerebral vasoconstriction by regulating calcium homeostasis during simulated microgravity.

Activation of BKCa channel is associated with increased apoptosis of cerebrovascular smooth muscle cells in simulated microgravity rats.

Cerebral arterial remodeling is one of the critical factors in the occurrence of postspaceflight orthostatic intolerance. We hypothesize that large-conductance calcium-activated K(+) (BK(Ca)) channels in vascular smooth muscle cells (VSMCs) may play an important role in regulating cerebrovascular adaptation during microgravity exposure. The aim of this work was to investigate whether activation of BK(Ca) channels is involved in regulation of apoptotic remodeling of cerebral arteries in simulated microgravity rats. In animal studies, Sprague-Dawley rats were subjected to 1-wk hindlimb unweighting to simulate microgravity. Alterations of BK(Ca) channels in cerebral VSMCs were investigated by patch clamp and Western blotting; apoptosis was assessed by electron microscopy and terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick-end labeling (TUNEL). To evaluate the correlation of BK(Ca) channel and apoptosis, channel protein and cell nucleus were double-stained. In cell studies, hSloalpha+beta1 channel was coexpressed into human embryonic kidney 293 (HEK293) cells to observe the effects of BK(Ca) channels on apoptosis. In rats, enhanced activities and expression of BK(Ca) channels were found to be correlated with increased apoptosis in cerebral VSMCs after simulated microgravity. In transfected HEK293 cells, activation of cloned BK(Ca) channel induced apoptosis, whereas inhibition of cloned BK(Ca) channel decreased apoptosis. In conclusion, activation of BK(Ca) channels is associated with increased apoptosis in cerebral VSMCs of simulated microgravity rats.

Activation of cloned BK(Ca) channels in nitric oxide-induced apoptosis of HEK293 cells.

The large conductance Ca(2+)-activated K(+) (BK(Ca)) channels are highly expressed in vascular smooth muscle cells (VSMCs) and play an essential role in the regulation of various physiological functions. Besides its electrophysiological function in vascular relaxation, BK(Ca) has also been reported to be implicated in nitric oxide (NO)-induced apoptosis of VSMCs. However, the molecular mechanism is not clear and has not been determined on cloned channels. The present study was designed to clarify whether activation of cloned BK(Ca) channel was involved in NO-induced apoptosis in human embryonic kidney 293 (HEK293) cell. The cDNA encoding the alpha-subunit of BK(Ca) channel, hSloalpha, was transiently transfected into HEK293 cells. The apoptotic death in HEK-hSloalpha cells was detected using immunocytochemistry, analysis of fragmented DNA by agarose gel electrophoresis, MTT test, and flow cytometry assays. Whole-cell and single-channel characteristics of HEK-hSloalpha cells exhibited functional features similar to native BK(Ca) channel in VSMCs. Exposuring of HEK- hSloalpha cells to S-nitroso-N-acetyl-penicillamine increased the hSloalpha channel activities of whole-cell and single-channel, and then increased percentage of cells undergoing apoptosis. However, blocking hSloalpha channels with 1 mM tetraethylammonia or 100 nM iberiotoxin significantly decreased the NO-induced apoptosis, whereas 30 microM NS1619, the specific agonist of BK(Ca), independently increased hSloalpha currents and induced apoptosis. These results indicated that activation of cloned BK(Ca) channel was involved in NO-induced apoptosis of HEK293 cells.

Evidence that apoptotic signalling in hypertrophic cardiomyocytes is determined by mitochondrial pathways involving protein kinase Cδ.

1. Cardiomyocyte apoptosis plays an important role in the transition from cardiac hypertrophy to heart failure. Hyper-trophic cardiomyocytes show an increased susceptibility to apoptotic stimuli, but the mechanisms remain unclear. 2. We hypothesized that activated protein kinase Cδ (PKCδ) associated with cardiomyocyte hypertrophy could move from the cytoplasm to mitochondria, and subsequently trigger the apoptotic signalling pathway. 3. Hypertrophy was induced in cultured neonatal rat cardiomyocytes using endothelin-1 (ET-1), insulin-like growth factor-1 (IGF-1), thyroid hormone (T(3) ) or angiotensin-II (AngII). AngII at high concentrations (1 and 10 nmol/L) also induced apoptosis. Hypertrophic cells were then treated with AngII with or without specific inhibitors of the angiotensin receptors AT(1) and AT(2) (losartan and PD123319, respectively), endothelin receptor A (BQ-123) and PKCδ (rottlerin). ET-1 plus AngII had a threefold and significant increase in apoptosis in the hypertrophic cultures compared with AngII alone. In association with the increase in apoptosis, this treatment also promoted mitochondrial translocation of PKCδ, and increased expression of cleaved caspase 9 and activity of caspase 3. All of these increases were modulated by concurrent use of the PKCδ inhibitor, rottlerin. 4. The results suggest that apoptotic signalling in hypertrophic cardiomyocytes is determined by mitochondrial pathways involving PKCδ.

miR-137 and its target T-type CaV 3.1 channel modulate dedifferentiation and proliferation of cerebrovascular smooth muscle cells in simulated microgravity rats by regulating calcineurin/NFAT pathway.

OBJECTIVES: Postflight orthostatic intolerance has been regarded as a major adverse effect after microgravity exposure, in which cerebrovascular adaptation plays a critical role. Our previous finding suggested that dedifferentiation of vascular smooth muscle cells (VSMCs) might be one of the key contributors to cerebrovascular adaptation under simulated microgravity. This study was aimed to confirm this concept and elucidate the underlying mechanisms. MATERIALS AND METHODS: Sprague Dawley rats were subjected to 28-day hindlimb-unloading to simulate microgravity exposure. VSMC dedifferentiation was evaluated by ultrastructural analysis and contractile/synthetic maker detection. The role of T-type CaV 3.1 channel was revealed by assessing its blocking effects. MiR-137 was identified as the upstream of CaV 3.1 channel by luciferase assay and investigated by gain/loss-of-function approaches. Calcineurin/nuclear factor of activated T lymphocytes (NFAT) pathway, the downstream of CaV 3.1 channel, was investigated by detecting calcineurin activity and NFAT nuclear translocation. RESULTS: Simulated microgravity induced the dedifferentiation and proliferation in rat cerebral VSMCs. T-type CaV 3.1 channel promoted the dedifferentiation and proliferation of VSMC. MiR-137 and calcineurin/NFATc3 pathway were the upstream and downstream signalling of T-type CaV 3.1 channel in modulating the dedifferentiation and proliferation of VSMCs, respectively. CONCLUSIONS: The present work demonstrated that miR-137 and its target T-type CaV 3.1 channel modulate the dedifferentiation and proliferation of rat cerebral VSMCs under simulated microgravity by regulating calcineurin/NFATc3 pathway.

Coexpression and characterization of the human large-conductance Ca(2+)-activated K (+) channel alpha + beta1 subunits in HEK293 cells.

Large-conductance Ca(2+)-activated K(+) channel is formed by a tetramer of the pore-forming alpha-subunit and distinct accessory beta-subunits (beta1-beta4) which contribute to BK(Ca) channel molecular diversity. Accumulative evidences indicate that not only alpha-subunit alone but also the alpha + beta subunit complex and/or beta-subunit might play an important role in modulating various physiological functions in most mammalian cells. To evaluate the detailed pharmacological and biophysical properties of alpha + beta1 subunit complex or beta1-subunit in BK(Ca) channel, we established an expression system that reliably coexpress hSloalpha + beta1 subunit complex in HEK293 cells. The coexpression of hSloalpha + beta1 subunit complex was evaluated by western blotting and immunolocalization, and then the single-channel kinetics and pharmacological properties of expressed hSloalpha + beta1 subunit complex were investigated by cell-attached and outside-out patches, respectively. The results in this study showed that the expressed hSloalpha + beta1 subunit complex demonstrated to be fully functional for its typical single-channel traces, Ca(2+)-sensitivity, voltage-dependency, high conductance (151 +/- 7 pS), and its pharmacological activation and inhibition.

Rotenone partially reverses decreased BK Ca currents in cerebral artery smooth muscle cells from streptozotocin-induced diabetic mice.

1. Reactive oxygen species (ROS) cause vascular complications and impair vasodilation in diabetes mellitus. Large-conductance Ca(2+)-activated potassium channels (BK(Ca)) modulate vascular tone and play an important negative feedback role in vasoconstriction. In the present study, we tested the hypothesis that ROS regulate the function of BK(Ca) in diabetic cerebral artery smooth muscle cells. 2. Diabetes was induced in male BALB/c mice by injection of streptozotocin (STZ; 180 mg/kg, i.p., dissolved in sterile saline). Control and diabetic mice were treated with 12.7 micromol/L rotenone, an inhibitor of the mitochondrial electron transport chain complex I, or placebo every other day for 5 weeks. The whole-cell patch clamp-technique and functional vasomotor methods were used to record BK(Ca) currents and myogenic tone of cerebral artery smooth muscle cells. 3. In the diabetic group, there was a significant decrease in spontaneous transient outward currents in cerebral artery smooth muscle cells compared with control. Although the currents were only moderately increased in rotenone-treated diabetic mice, they remained significantly lower than in the control group. Furthermore, the macroscopic BK(Ca) currents that were decreased in diabetic mice were partially recovered in rotenone-treated diabetic mice (P < 0.05 vs untreated diabetic group). 4. The posterior cerebral artery from diabetic mice had a significantly higher myogenic tone than the control group, but this impaired contraction was partially reversed in the rotenone-treated diabetic group (P < 0.05 vs untreated diabetic group). 5. The H(2)O(2) concentration was significantly increased in cerebral arteries from diabetic mice compared with control. This increase in H(2)O(2) was significantly blunted by rotenone treatment. 6. In conclusion, rotenone partially reverses the decreased macroscopic BK(Ca) currents in STZ-induced Type 1 diabetic mice and this reversal of BK(Ca) currents may be related to the inhibitory effects of rotenone on H(2)O(2) production. Reactive oxygen species, particularly H(2)O(2), are important regulators of BK(Ca) channels and myogenic tone in diabetic cerebral artery.

Salidroside contributes to reducing blood pressure and alleviating cerebrovascular contractile activity in diabetic Goto-Kakizaki Rats by inhibition of L-type calcium channel in smooth muscle cells.

BACKGROUND: Vascular disease is a common and often severe complication in diabetes mellitus. Hyperglycemia and hypertension are considered to be two of the leading risk factors for vascular complications in diabetic patients. However, few pharmacologic agents could provide a combinational therapy for controlling hyperglycemia and blood pressure in diabetic patients at the same time. Salidroside (SAL) is the major active ingredient derived from Rhodiola. Recently, it has been reported that SAL have an obvious hypoglycemic effect in diabetes and show a beneficial activity in diabetic vascular dysfunction. However, it remains unknown whether or not SAL treatment could directly reduce blood pressure in diabetes. Furthermore, it is not clear what is the molecular mechanism underlying the vascular protection of SAL treatment in diabetes. METHODS: Male diabetic Goto-Kakizaki (GK) and non-diabetic control Wistar-Kyoto (WKY) rats were administrated with different dosages of SAL (50, 100 and 200 mg/kg/day) for 4 weeks. Contractile responsiveness of cerebral artery to KCl or 5-HT was investigated by Pressure Myograph System. The activity of CaL channel was investigated by recording whole-cell currents, assessing the expressions of CaL channel α1C-subunit and its downstream kinase, MLCK, at protein or mRNA levels. RESULTS: We showed that administration of 100 mg/kg/day SAL for 4 weeks not only lowered blood glucose, but also reduced blood pressure and alleviated cerebrovascular contractile activity in diabetic GK rats, which suggested that SAL treatment may provide a combinational therapy for lowering blood glucose and reducing blood pressure in diabetes at the same time. Furthermore, SAL treatment markedly inhibited the function and expression of CaL channel in cerebral VSMCs isolated from diabetic GK rats or when exposed to hyperglycemia condition, which may be the underlying mechanism responsible for the vascular protection of SAL in diabetes. CONCLUSIONS: The present study provided evidences that SAL contributes to reducing blood pressure and alleviating cerebrovascular contractile activity in diabetic GK rats by inhibition of CaL channel in smooth muscle cells, which may provide a novel approach to treat vascular complications in diabetic patients.

DDX5 promotes gastric cancer cell proliferation in vitro and in vivo through mTOR signaling pathway.

DEAD (Asp-Glu-Ala-Asp) box helicase 5 (DDX5) is an ATP-dependent RNA helicase that is overexpressed in various malignancies. Increasing evidence suggests that DDX5 participates in carcinogenesis and cancer progression via promoting cell proliferation and metastasis. However, the functional role of DDX5 in gastric cancer is largely unknown. In this study, we observed that DDX5 was significantly up-regulated in gastric cancer tissues compared with the paired adjacent normal tissues. The expression of DDX5 correlated strongly with Ki67 index and pathological stage of gastric cancer. In vitro and in vivo studies suggested that knockdown of DDX5 inhibited gastric cancer cell proliferation, colony formation and xenografts growth, whereas ectopic expression of DDX5 promoted these cellular functions. Mechanically, DDX5 induced gastric cancer cell growth by activating mTOR/S6K1. Treatment of everolimus, the specific mTOR inhibitor, significantly attenuated DDX5-mediated cell proliferation. Interestingly, the expression of DDX5 and p-mTOR in gastric cancer tissues demonstrated a positive correlation. Taken together, these results revealed a novel role of DDX5 in gastric cancer cell proliferation via the mTOR pathway. Therefore, DDX5 may serve as a therapeutic target in gastric cancer.

Berberine reduced blood pressure and improved vasodilation in diabetic rats.

Hyperglycemia and hypertension are considered to be the two leading risk factors for vascular disease in diabetic patients. However, few pharmacologic agents could provide a combinational therapy for controlling hyperglycemia and hypertension at the same time in diabetes. The objectives of this study are to investigate whether berberine treatment could directly reduce blood pressure and identify the molecular mechanism underlying the vascular protection of berberine in diabetic rats. Berberine was intragastrically administered with different dosages of 50, 100 and 200 mg/kg/day to diabetic rats for 8 weeks since the injection of streptozotocin. The endothelium-dependent/-independent relaxation in middle cerebral arteries was investigated. The activity of large-conductance Ca2+-activated K+ channel (BKCa) was investigated by recording whole-cell currents, analyzing single-channel activities and assessing the expressions of α- and ß1-subunit at protein or mRNA levels. Results of the study suggest that chronic administration of 100 mg/kg/day berberine not only lowered blood glucose but also reduced blood pressure and improved vasodilation in diabetic rats. Furthermore, berberine markedly increased the function and expression of BKCa ß1-subunit in cerebral vascular smooth muscle cells (VSMCs) isolated from diabetic rats or when exposed to hyperglycemia condition. The present study provided initial evidences that berberine reduced blood pressure and improved vasodilation in diabetic rats by activation of BKCa channel in VSMCs, which suggested that berberine might provide a combinational therapy for controlling hyperglycemia and blood pressure in diabetes. Furthermore, our work indicated that activation of BKCa channel might be the underlying mechanism responsible for the vascular protection of berberine in diabetes.

[Protein kinase Cdelta is possibly involved in the transition from hypertrophy to apoptosis of myocardiocytes].

Cardiac hypertrophy is an adaptive process to an increased hemodynamic overload. However, the adaption may lead to the fragility of myocardium facing pathological stimuli. In the present study, experiments were designed to explore the susceptibility of hypertrophic myocardiocytes to apoptotic stimuli and the role of protein kinase Cdelta (PKCdelta) during the transition from hypertrophy to apoptosis. Endothelin-1 (ET-1)-treated cardiomyocytes were used as model of cardiac hypertrophy. Angiotensin II (Ang II) was used as an apoptotic stimulus. Cell surface area was measured to determine the extent of hypertrophy. The apoptotic rate in cardiomyocytes was detected by Hoechst 33258. (1) Cell surface area was increased by 42.5% and 67.3% following 1 nmol/L and 10 nmol/L ET-1 treatment, respectively, as compared with serum-free cultured myocytes. So the mildly and moderately hypertrophic myocyte models were set up. (2) Apoptotic rates in serum-free cultured, mildly and moderately hypertrophic myocytes after Ang II treatment were (15.54+/-1.32) %, (20.65+/-1.40) % and (29.33+/-3.52) %, respectively. It is suggested that hypertrophic myocytes are more susceptive to apoptotic stimulus. (3) Rottlerin, a specific inhibitor of PKCdelta depressed apoptotic rates induced by Ang II to (15.88+/-2.25) % in mildly hypertrophic myocytes and to (15.01+/-1.37) % in moderately hypertrophic myocytes; but rottlerin did not affect apoptotic rate induced by Ang II in serum-free cultured myocytes. These results suggest that inhibition of PKCdelta can reduce Ang II-induced apoptosis of hypertrophic cardiomyocytes and that PKCdelta is possibly involved in the apoptotic process of hypertrophic cardiomyocytes.

[Enhanced BK(Ca) single-channel activities in cerebrovascular smooth muscle cells of simulated microgravity rats.].

The aim of the present study was to investigate the changes in single-channel currents of large conductance calcium-activated potassium channels (BK(Ca) channels) in cerebral vascular smooth muscle cells (VSMCs) of rats after 1-week simulated microgravity. Sprague-Dawley rats were subjected to tail-suspension (SUS) to simulate cardiovascular deconditioning due to microgravity. Cytosolic calcium ([Ca(2+)](i)) was examined by laser-scanning confocal microscopy with calcium-sensitive-dye Fluo-3/AM as fluorescent probe. Single-channel currents of BK(Ca) channels were measured with cell-attached membrane patches bathed in symmetrical high potassium solution. The [Ca(2+)](i)i level was significantly higher in cerebrovascular myocytes of SUS than that of control (CON) rats. The probability of open (Po) and the mean open time (To) of BK(Ca) channels in cerebral VSMCs significantly increased in SUS as compared with CON. However, there were no significant differences in the unitary conductance and mean close time (Tc) between the two groups. The results obtained suggest that both the elevated [Ca(2+)](i) and enhanced single-channel activities of BK(Ca) channels in cerebral VSMCs might be among the electrophysiological mechanisms that mediate the increased vasoreactivity and hypertrophic change in cerebral arteries during adaptation to simulated microgravity in rats.