Discovery of Salidroside as a Novel Non-Coding RNA Modulator to Delay Cellular Senescence and Promote BK-Dependent Apoptosis in Cerebrovascular Smooth Muscle Cells of Simulated Microgravity Rats.

Cardiovascular aging has been reported to accelerate in spaceflights, which is a great potential risk to astronauts' health and performance. However, current exercise routines are not sufficient to reverse the adverse effects of microgravity exposure. Recently, salidroside (SAL), a valuable medicinal herb, has been demonstrated to display an important role for prevention and treatment in cardiovascular and other diseases. In the present work, Sprague-Dawley rats with four-week tail-suspension hindlimb-unloading were used to simulate microgravity effects on the cardiovascular system. We found that intragastrical administration of SAL not only significantly decreased the expressions of senescence biomarkers, such as P65 and P16, but also obviously increased the expressions of BK-dependent apoptotic genes, including the large-conductance calcium-activated K+ channel (BK), Bax, Bcl-2, and cleaved caspase-3, in vascular smooth muscle cells (VSMCs) in vivo and in vitro. In addition, relative non-coding RNAs were screened, and a luciferase assay identified that SAL increased apoptosis by activating LncRNA-FLORPAR, inhibiting miR-193, and then triggering the activity of the BK-α subunit. Our work indicated that SAL is a novel non-coding RNA modulator for regulating the LncRNA-FLORPAR sponging miR-193 pathway, which significantly promoted BK-dependent apoptosis and delayed cerebrovascular aging-like remodeling during simulated microgravity exposure. Our findings may provide a new approach to prevent cardiovascular aging in future spaceflights.

Integrated transcriptomics and metabolomics reveal protective effects on heart of hibernating Daurian ground squirrels.

Hibernating mammals are natural models of resistance to ischemia, hypoxia-reperfusion injury, and hypothermia. Daurian ground squirrels (spermophilus dauricus) can adapt to endure multiple torpor-arousal cycles without sustaining cardiac damage. However, the molecular regulatory mechanisms that underlie this adaptive response are not yet fully understood. This study investigates morphological, functional, genetic, and metabolic changes that occur in the heart of ground squirrels in three groups: summer active (SA), late torpor (LT), and interbout arousal (IBA). Morphological and functional changes in the heart were measured using hematoxylin-eosin (HE) staining, Masson staining, echocardiography, and enzyme-linked immunosorbent assay (ELISA). Results showed significant changes in cardiac function in the LT group as compared with SA or IBA groups, but no irreversible damage occurred. To understand the molecular mechanisms underlying these phenotypic changes, transcriptomic and metabolomic analyses were conducted to assess differential changes in gene expression and metabolite levels in the three groups of ground squirrels, with a focus on GO and KEGG pathway analysis. Transcriptomic analysis showed that differentially expressed genes were involved in the remodeling of cytoskeletal proteins, reduction in protein synthesis, and downregulation of the ubiquitin-proteasome pathway during hibernation (including LT and IBA groups), as compared with the SA group. Metabolomic analysis revealed increased free amino acids, activation of the glutathione antioxidant system, altered cardiac fatty acid metabolic preferences, and enhanced pentose phosphate pathway activity during hibernation as compared with the SA group. Combining the transcriptomic and metabolomic data, active mitochondrial oxidative phosphorylation and creatine-phosphocreatine energy shuttle systems were observed, as well as inhibition of ferroptosis signaling pathways during hibernation as compared with the SA group. In conclusion, these results provide new insights into cardio-protection in hibernators from the perspective of gene and metabolite changes and deepen our understanding of adaptive cardio-protection mechanisms in mammalian hibernators.

Dapagliflozin delays renal fibrosis in diabetic kidney disease by inhibiting YAP/TAZ activation.

In diabetic kidney disease (DKD), the long-term hyperactivation of yes-associated protein (YAP)/transcriptional coactivator PDZ-binding motif (TAZ) in renal proximal tubule epithelial cells (RPTCs) plays an important role in progressive tubulointerstitial fibrosis. Sodium-glucose cotransporter 2 (SGLT2) is highly expressed in RPTCs, but its relationship with YAP/TAZ in tubulointerstitial fibrosis in DKD is still unknown. The purpose of this study was to clarify whether the SGLT2 inhibitor (SGLT2i) dapagliflozin could alleviate renal tubulointerstitial fibrosis in DKD by regulating YAP/TAZ. We examined 58 patients with DKD confirmed by renal biopsy and found that the expression and nuclear translocation of YAP/TAZ increased with the exacerbation of chronic kidney disease classification. In models of DKD, dapagliflozin showed similar effects to verteporfin, an inhibitor of YAP/TAZ, in reducing the activation of YAP/TAZ and downregulating the expression of their target genes, connective tissue growth factor (CTGF) and amphiregulin in vivo and in vitro. Silencing SGLT2 also confirmed this effect. Importantly, dapagliflozin showed a better effect than verteporfin in inhibiting inflammation, oxidative stress and fibrosis in the kidney in DKD rats. Taken together, this study proved for the first time that dapagliflozin delayed tubulointerstitial fibrosis at least partly by inhibiting YAP/TAZ activation, which further enriched the antifibrotic effect of SGLT2i.

Differential bone remodeling mechanism in hindlimb unloaded and hibernating Daurian ground squirrels: a comparison between artificial and natural disuse within the same species.

Loss of bone mass can occur in mammals after prolonged disuse but the situation for hibernators that are in a state of torpor for many months of the year is not yet fully understood. The present study assesses the bone remodeling mechanisms present in Daurian ground squirrels (Spermophilus dauricus) during hibernation as compared with a model of hindlimb disuse. Differences in microstructure, mechanical properties, bone remodeling-related proteins (Runx2, OCN, ALP, RANKL, CTK and MMP-9) and key proteins of Wnt/ß-catenin signaling pathway (GSK-3ß and phospho-ß-catenin) were evaluated in ground squirrels under 3 conditions: summer active (SA) vs. hibernation (HIB) vs. hindlimb unloaded (HLU). The results indicated that the body weight in HLU ground squirrels was lower than the SA group, and the middle tibia diameter in the HLU group was lower than that in SA and HIB groups. The thickness of cortical and trabecular bone in femurs from HLU ground squirrels was lower than in SA and HIB groups. Most parameters of the tibia in the HLU group were lower than those in SA and HIB groups, which indicated cortical bone loss in ground squirrels. Moreover, our data showed that the changes in microscopic parameters in the femur were more obvious than those in the tibia in HLU and HIB ground squirrels. The levels of Runx2 and ALP were lower in HLU ground squirrels than SA and HIB groups. The protein levels of OCN were unchanged in the three groups, but the protein levels of ALP were lower in the HLU group than in SA and HIB groups. RANKL, CTK and MMP-9 protein levels were significantly decreased in tibia of HLU ground squirrels as compared with SA and HIB groups. In addition, the protein expression levels of RANKL, CTK and MMP-9 showed no statistical difference between SA and HIB ground squirrels. Thus, the mechanisms involved in the balance between bone formation and resorption in hibernating and hindlimb unloading ground squirrels may be different. The present study showed that in femur, the Wnt signaling pathway was inhibited, the protein level of GSK-3ß was increased, and the protein expression of phospho-ß-catenin was decreased in the HIB group as compared with the SA group, which indicates that the Wnt signaling pathway has a great influence on the femur of the HIB group. In conclusion, the natural anti-osteoporosis properties of Daurian ground squirrels are seasonal. The squirrels do not experience bone loss when they are inactive for a long time during hibernation, but the mechanisms of anti-osteoporosis did not work in HLU summer active squirrels.

[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.

Real-time monitoring hypoxia at high altitudes using electrical bioimpedance technique: an animal experiment.

Hypoxia poses a serious threat to pilots. The aim of this study was to examine the efficacy of electrical bioimpedance (EBI) in detecting the onset of hypoxia in real time in a rabbit hypoxia model. Thirty-two New Zealand rabbits were divided equally into four groups (control group and three hypoxia groups, i.e., mild, moderate, and severe). Hypoxia was induced by simulating various altitudes in the hypobaric oxygen chamber (3,000 m, 5,000 m, and 8,000 m). Both cerebral impedance and blood oxygen (SpO2) were monitored continuously. Results showed that the cerebral impedance increased immediately during the period of increasing altitude and decreased quickly to the initial baseline at the phase of descending altitude. Moreover, the change of cerebral impedance in the mild hypoxia group (3,000 m) was significantly smaller than those in the other two groups (5,000 m and 8,000 m, P < 0.05). The changes in cerebral impedance and SpO2 were significantly correlated based on the total of measurement data (r2 = 0.628, P < 0.001). Furthermore, the agreement analysis performed with Bland-Altman and standardized residual plots exhibited high concordance between cerebral impedance and SpO2. Receiver operator characteristic analysis manifested that the sensitivity, specificity, and area under the curve using cerebral impedance for changes in SpO2 >10% were 0.735, 0.826, and 0.845, respectively. These findings demonstrated that EBI could sensitively and accurately monitor changes of cerebral impedance induced by hypoxia, which might provide a potential tool for the real-time and noninvasive monitoring of hypoxic condition of pilots in flight for early identification of hypoxia.NEW & NOTEWORTHY This study is the first to examine the efficacy of electrical bioimpedance (EBI) in detecting the onset of high-altitude hypoxia in real time. The novelty of this research includes three aspects. First, the cerebral impedance of rabbits increased immediately during the rising of altitude and decreased quickly to the initial baseline at the phase of descending altitude. Second, there was a significant correlation and high concordance between cerebral impedance and SpO2. Third, cerebral impedance could determine the change of SpO2 resulting from hypoxia.

Endoplasmic reticulum stress-dependent activation of iNOS/NO-NF-κB signaling and NLRP3 inflammasome contributes to endothelial inflammation and apoptosis associated with microgravity.

Exposure to microgravity results in vascular remodeling and cardiovascular dysfunction. To elucidate the mechanism involved in this condition, we investigated whether endoplasmic reticulum (ER) stress during simulated microgravity induced endothelial inflammation and apoptosis in human umbilical vein endothelial cells (HUVECs). Microgravity was simulated by clinorotation in the current study. We examined markers of ER stress, inducible nitric oxide (NO) synthase (iNOS)/NO content, proinflammatory cytokine production, nuclear factor kappa B (NF-κB)/IκB signaling, NLRP3 inflammasome, and detected apoptosis in HUVECs. We found that the levels of C/EBP homologous protein and glucose-regulated protein 78, pro-inflammatory cytokines (IL-6, TNF-α, IL-8, and IL-1ß), and iNOS/NO content were upregulated by clinorotation. ER stress inhibition with tauroursodeoxycholic acid or 4-phenylbutyric acid and iNOS inhibition with 1400 W dramatically suppressed activation of the NF-κB/IκB pathway and the NLRP3 inflammasome, and decreased the production of pro-inflammatory cytokines. The increase of apoptosis in HUVECs during clinorotation was significantly suppressed by inhibiting ER stress, iNOS activity, NF-κB/IκB, and the NLRP3 inflammasome signaling pathway. Therefore, simulated microgravity causes ER stress in HUVECs, and subsequently activates iNOS/NO-NF-κB/IκB and the NLRP3 inflammasome signaling pathway, which have key roles in the induction of endothelial inflammation and apoptosis.

P53/PANK1/miR-107 signalling pathway spans the gap between metabolic reprogramming and insulin resistance induced by high-fat diet.

High-fat diet (HFD) leads to obesity, type II diabetes mellitus (T2DM) and increases the coincidence of cardiovascular diseases and cancer. Insulin resistance (IR) is considered as the 'common soil' of those diseases. Furthermore, people on HFD showed restrained glycolysis and enhanced fatty acid oxidation, which is the so-called metabolic reprogramming. However, the relationship between metabolic reprogramming and IR induced by HFD is still unclear. Here, we demonstrate that PANK1 and miR-107 were up-regulated in the liver tissue of mice on HFD for 16 weeks and involved in metabolic reprogramming induced by palmitate acid (PA) incubation. Importantly, miR-107 within an intron of PANK1 gene facilitated IR by targeting caveolin-1 in AML12 cells upon PA incubation. Moreover, we identify that HFD enhanced P53 expression, and activation of P53 with nutlin-3a induced PANK1 and miR-107 expression simultaneously in transcriptional level, leading to metabolic reprogramming and IR, respectively. Consistently, inhibition of P53 with pifithrin-α hydrobromide ameliorated PA-induced metabolic reprogramming and IR. Thus, our results revealing a new mechanism by which P53 regulate metabolism. In addition, the results distinguished the different roles of PANK1 and its intron miR-107 in metabolic regulation, which will provide more accurate intervention targets for the treatment of metabolic diseases.

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.

BKCa compensates impaired coronary vasoreactivity through RhoA/ROCK pathway in hind-limb unweighted rats.

Previous studies have demonstrated cardiac and vascular remodeling induced by microgravity exposure. Yet, as the most important branch of vasculatures circulating the heart, the coronary artery has been seldomly studied about its adaptations under microgravity conditions. Large-conductance Ca2+-activated potassium channel (BKCa) and the Ras homolog family member A (RhoA)/Rho kinase (ROCK) pathway play key roles in control of vascular tone and mediation of microgravity-induced vascular adjustments. Therefore, we investigated the adaptation of coronary vasoreactivity to simulated microgravity and the role of BKCa and the RhoA/ROCK pathway in it. Four-week-old hind-limb unweighted (HU) rats were adopted to simulate effects of microgravity. Right coronary artery (RCA) constriction was measured by isometric force recording. The activity and expression of BKCa and the RhoA/ROCK pathway were examined by Western blot, patch-clamp recordings, and immunoprecipitation. We found HU significantly decreased RCA vasoconstriction to KCl, serotonin, and U-46619, but increased protein expression and current densities of BKCa, inhibition of which by iberiotoxin (IBTX) further decreased RCA vasoconstriction (P < 0.05). Expression of RhoA and ROCK as well as active RhoA and phosphorylation of myosin light chain (MLC) at Ser19 and MLC phosphatase target-1 at Thr696 were significantly increased by HU, and ROCK inhibitor Y-27632 exerted greater suppressing effect on HU RCA vasoconstriction than that of control (P < 0.05). BKCa opener NS1619 increased HU RCA vasoconstriction, which was blocked by both RhoA and ROCK inhibitor, similar to the effect of IBTX. These results indicate that HU impairs coronary vasoconstriction but enhances BKCa activity acting as a protective mechanism avoiding excessive decrease of coronary vasoreactivity through activation of the RhoA/ROCK pathway.-Wu, Y., Yue, Z., Wang, Q., Lv, Q., Liu, H., Bai, Y., Li, S., Xie, M., Bao, J., Ma, J., Zhu, X., Wang, Z. BKCa compensates impaired coronary vasoreactivity through RhoA/ROCK pathway in hind-limb unweighted rats.

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 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.

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.

BKCa promotes growth and metastasis of prostate cancer through facilitating the coupling between αvß3 integrin and FAK.

BKCa is a large conductance calcium activated potassium channel promoting prostate cancer cell proliferation, although the mechanism is not fully elucidated. In addition, whether BKCa is involved in metastasis of prostate cancer remains to be explored. Here, we report that BKCa is overexpressed in prostate cancer. BKCa expression positively correlates with Ki67 index and gleason score of prostate cancer. Upregulation of BKCa promoted proliferation, migration and invasion of prostate cancer cells. On the contrary, downregulation of BKCa inhibited growth and metastasis of prostate cancer cells both in vitro and in vivo. Moreover, the ion-conducting function of BKCa contributed moderately to prostate cancer proliferation and migration, although, this was not the primary mechanism. BKCa action was mainly mediated through forming a functional complex with αvß3 integrin. The BKCa/αvß3 integrin complex promoted FAK phosphorylation independent of the channel activity. Overexpression of BKCa enhanced its association with αvß3 integrin and FAK which increased FAK phosphorylation. Conversely, disrupting the complex by downregulation of BKCa reduced FAK phosphorylation. Finally, blocking of αvß3 integrin or p-FAK activity using LM609 or Y15 markedly abrogated BKCa-enhanced cell proliferation and migration. Taken together, these results suggest that targeting BKCa/αvß3/FAK may inaugurate innovative approaches to inhibit prostate cancer growth and metastasis.

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.

Nitric Oxide Protects L-Type Calcium Channel of Cardiomyocyte during Long-Term Isoproterenol Stimulation in Tail-Suspended Rats.

The aim of this study was to investigate the effects of nitric oxide (NO) and reactive oxygen species (ROS) on L-type calcium channel (LTCC) gating properties of cardiomyocytes during long-term isoproterenol (ISO) stimulation. Expression and activity of nNOS as well as S-nitrosylation of LTCC α1C subunit significantly decreased in the myocardium of SUS rats. Long-term ISO stimulation increased ROS in cardiomyocytes of SUS rats. ISO-enhanced calcium current (I Ca,L) in the SUS group was less than that in the CON group. The maximal I Ca,L decreased to about 80% or 60% of initial value at the 50th minute of ISO treatment in CON or SUS group, respectively. Specific inhibitor NAAN of nNOS reduced maximal I Ca,L to 50% of initial value in the CON group; in contrast, NO donor SNAP maintained maximal I Ca,L in SUS group to similar extent of CON group after 50 min of ISO treatment. Long-term ISO stimulation also changed steady-state activation (P < 0.01), inactivation (P < 0.01), and recovery (P < 0.05) characteristics of LTCC in SUS group. In conclusion, NO-induced S-nitrosylation of LTCC α1C subunit may competitively prevent oxidation from ROS at the same sites. Furthermore, LTCC can be protected by NO during long-term ISO stimulation.

MiR-103 inhibits osteoblast proliferation mainly through suppressing Cav1.2 expression in simulated microgravity.

Emerging evidence indicates that microRNAs (miRNAs) play important roles in modulating osteoblast function and bone formation. However, the influence of miRNA on osteoblast proliferation and the possible mechanisms underlying remain to be defined. In this study, we aimed to investigate whether miR-103 regulates osteoblast proliferation under simulated microgravity condition through regulating Cav1.2, the primary subunit of L-type voltage sensitive calcium channels (LTCCs). We first investigated the effect of simulated microgravity on osteoblast proliferation and the outcomes clearly demonstrated that the mechanical unloading inhibits MC3T3-E1 osteoblast-like cell proliferation. Using quantitative Real-Time PCR (qRT-PCR), we provided data showing that miR-103 was up-regulated in response to simulated microgravity. In addition, we observed that up-regulation of miR-103 inhibited and down-regulation of miR-103 promoted osteoblast proliferation under simulated microgravity condition. Furthermore, knocking-down or over-expressing miR-103, respectively, up- or down-regulated the level of Cav1.2 expression and LTCC currents, suggesting that miR-103 acts as an endogenous attenuator of Cav1.2 in osteoblasts under simulated microgravity condition. More importantly, we showed that the effect of miR-103 on osteoblast proliferation was diminished in simulated microgravity, when co-transfecting miR-103 mimic or inhibitor with Cav1.2 siRNA. Taken together, our data suggest that miR-103 inhibits osteoblast proliferation mainly through suppression of Cav1.2 expression under simulated microgravity condition. This work may provide a novel mechanism of microgravity-induced detrimental effects on osteoblast proliferation, identifying miR-103 as a novel possible therapeutic target in bone remodeling disorders in this mechanical unloading.

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.