Acacetin alleviates autoimmune myocarditis by regulating CD4+ T cell mitochondrial respiration.

BACKGROUND: Myocarditis refers to an autoimmune inflammatory response of the myocardium with characterization of self-reactive CD4+ T cell activation, which lacks effective treatment and has a poor prognosis. Acacetin is a natural flavonoid product that has been reported to have anti-inflammatory effects. However, acacetin has not been investigated in myocarditis. METHODS: Oral acacetin treatment was administered in an experimental autoimmune myocarditis model established with myosin heavy chain-alpha peptide. Echocardiography, pathological staining, and RT-qPCR were used to detect cardiac function, myocardial injury, and inflammation levels. Flow cytometry was utilized to detect the effect of acacetin on CD4+ T cell function. RNA-seq, molecular docking, and microscale thermophoresis (MST) were employed to investigate potential mechanisms. Seahorse analysis, mitoSOX, JC-1, and mitotracker were utilized to detect the effect of acacetin on mitochondrial function. RESULTS: Acacetin attenuated cardiac injury and fibrosis as well as heart dysfunction, and reduced cardiac inflammatory cytokines and ratio of effector CD4+ T and Th17 cells. Acacetin inhibited CD4+ T cell activation, proliferation, and Th17 cell differentiation. Mechanistically, the effects of acacetin were related to reducing mitochondrial complex II activity thereby inhibiting mitochondrial respiration and mitochondrial reactive oxygen species in CD4+ T cells. CONCLUSION: Acacetin may be a valuable therapeutic drug in treating CD4+ T cell-mediated myocarditis.

A survey of caregiver burden for stroke survivors in non-teaching hospitals in Western China.

The social factors that moderate stroke caregiver burden have been found to be culture- and gender-specific. We examined the factors that influence the social support and self-efficacy of caregivers of stroke survivors and the burden of caregiving in China. To determine the caregiver burden of stroke survivors, their social support, and their self-efficacy. A total of 328 stroke survivors and their caregivers were recruited from 4 tertiary medical centers to participate in this cross-sectional study. The sociodemographic and stroke-related characteristics of the participants were obtained. Perceived social support and self-efficacy were assessed using the Social Support Rating Scale and General Self-efficacy Scale, respectively. Caregiver burden was assessed using the Zarit Burden Interview Scale. Relationships between the variables were assessed using Pearson's correlation, the chi-square test, and a paired t test. A total of 27.4% of the caregivers reported receiving adequate social support, while 20.7% reported high levels of self-efficacy. A total of 67.1% of the caregivers experienced varying degrees of care burden, while the remaining 32.9% felt no burden. Participants' sociodemographic characteristics (age, daily care time, self-rated health, and financial situation) were significantly related to caregiver burden, social support, and self-efficacy (P < .001). The findings indicate an inverse relationship between caregiver burden, social support and self-efficacy. Adequate social support and self-efficacy can reduce stroke caregivers' burden. Hospital departments should provide assistance to stroke caregivers through educational programs and group training to increase their social support and self-efficacy, thereby alleviating their burden.

Heart-targeting exosomes from human cardiosphere-derived cells improve the therapeutic effect on cardiac hypertrophy.

Exosomes of human cardiosphere-derived cells (CDCs) are very promising for treating cardiovascular disorders. However, the current challenge is inconvenient delivery methods of exosomes for clinical application. The present study aims to explore the potential to enhance the therapeutic effect of exosome (EXO) from human CDCs to myocardial hypertrophy. A heart homing peptide (HHP) was displayed on the surface of exosomes derived from CDCs that were forced to express the HHP fused on the N-terminus of the lysosomal-associated membrane protein 2b (LAMP2b). The cardiomyocyte-targeting capability of exosomes were analyzed and their therapeutic effects were evaluated in a mouse model of myocardial hypertrophy induced by transverse aorta constriction (TAC). The molecular mechanisms of the therapeutic effects were dissected in angiotensin II-induced neonatal rat cardiomyocyte (NRCMs) hypertrophy model using a combination of biochemistry, immunohistochemistry and molecular biology techniques. We found that HHP-exosomes (HHP-EXO) accumulated more in mouse hearts after intravenous delivery and in cultured NRCMs than control exosomes (CON-EXO). Cardiac function of TAC mice was significantly improved with intravenous HHP-EXO administration. Left ventricular hypertrophy was reduced more by HHP-EXO than CON-EXO via inhibition of ß-MHC, BNP, GP130, p-STAT3, p-ERK1/2, and p-AKT. Similar results were obtained in angiotensin II-induced hypertrophy of NRCMs, in which the beneficial effects of HHP-EXO were abolished by miRNA-148a inhibition. Our results indicate that HHP-EXO preferentially target the heart and improve the therapeutic effect of CDCs-exosomes on cardiac hypertrophy. The beneficial therapeutic effect is most likely attributed to miRNA-148a-mediated suppression of GP130, which in turn inhibits STAT3/ERK1/2/AKT signaling pathway, leading to improved cardiac function and remodeling.

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OBJECTIVES: To study the association between neonatal discharge preparedness and adverse health events. METHODS: The neonates who were born in hospitals from different regions of Gansu Province in China and their parents were enrolled as subjects, and an investigation was performed for the discharge preparedness. According to the level of discharge preparedness, the subjects were divided into low-, middle-, and high-level groups. The neonates were followed up to observe the incidence rate of adverse health events within one month after discharge. The association between neonatal discharge preparedness and adverse health events was analyzed. RESULTS: The neonates with adverse health events had a significantly lower level of discharge preparedness than those without adverse events (P<0.05). The multivariate logistic regression analysis showed that the incidence rate of adverse health events was reduced by 34.8% in the middle-level group and 78.7% in the high-level group compared with the low-level group (P<0.05). The readmission rate of neonates was 8.1% (35/430), and the neonates readmitted had a significantly lower level of discharge preparedness than those not readmitted (P<0.05). The multivariate logistic regression analysis showed that the readmission rate of neonates was reduced by 67.4% in the middle-level group and 84.2% in the high-level group compared with the low-level group (P<0.05). CONCLUSIONS: Discharge preparedness may affect the incidence of adverse health events and the rate of readmission within one month after discharge. Medical staff should adopt effective intervention measures to improve discharge preparedness, so as to reduce the incidence of adverse health events and the rate of readmission.

Acacetin attenuates diabetes-induced cardiomyopathy by inhibiting oxidative stress and energy metabolism via PPAR-α/AMPK pathway.

Diabetic cardiomyopathy seriously affects the life quality of diabetic patients and can lead to heart failure and death in severe cases. Acacetin was reported to be an anti-oxidant and anti-inflammatory agent in several cardiovascular diseases. However, the effect of acacetin on diabetic cardiomyopathy was not understood. This study was designed to explore the therapeutic effect of acacetin on diabetic cardiomyopathy and the potential mechanism with in vitro and in vivo experimental techniques. In cultured neonatal rat cardiomyocytes and H9C2 cardiac cells, acacetin (0.3, 1, 3 µM) showed effective protection against high glucose-induced injury in a concentration-dependent manner. Acacetin countered high glucose-induced increase of Bax and decrease of Bcl-2, SOD1, and SOD2. In streptozotocin-induced rat diabetic cardiomyopathy model, treatment with acacetin prodrug (10 mg/kg, s.c., b.i.d.) significantly improved the cardiac function and reduced myocardial injury, and reversed the increase of serum MDA, Ang Ⅱ, and IL-6 levels and myocardial Bax and IL-6, and the decrease of serum SOD, indicating that acacetin plays a cardioprotective effect by inhibiting oxidative stress, inflammation, and apoptosis. In addition, both in vitro and in vivo experimental results showed that acacetin increased the expression of PPAR-α and pAMPK, indicating that PPAR-α and pAMPK are potential targets of acacetin for the protection against diabetic cardiomyopathy. This study demonstrates the new application of acacetin for treating diabetic cardiomyopathy.

Acacetin ameliorates cardiac hypertrophy by activating Sirt1/AMPK/PGC-1α pathway.

Cardiac hypertrophy is a major risk factor for developing heart failure. This study investigates the effects of the natural flavone acacetin on myocardial hypertrophy in cellular level and whole animals. In cardiomyocytes from neonatal rat with hypertrophy induced by angiotensin II (Ang II), acacetin at 0.3, 1, and 3 µM reduced the increased myocyte surface area, brain natriuretic peptide (BNP), and ROS production by upregulating anti-oxidative molecules (i.e. Nrf2, SOD1, SOD2, HO-1), anti-apoptotic protein Bcl-2, and downregulating the pro-apoptotic protein Bax and the inflammatory cytokine IL-6 in a concentration-dependent manner. In addition, acacetin rescued Ang II-induced impairment of PGC-1α, PPARα and pAMPK. These beneficial effects of acacetin were mediated by activation of Sirt1, which was confirmed in cardiac hypertrophy induced by abdominal aorta constriction (AAC) in SD rats. Acacetin prodrug (10 mg/kg, s.c., b.i.d.) treatment reduced the elevated artery blood pressure, improved the increased heart size and thickness of left ventricular wall and the ventricular fibrosis associated with inhibiting myocardial fibrosis and BNP, and reversed the impaired protective signal molecules including PGC-1α, Nrf2, PPARα, pAMPK and Sirt1 of left ventricular tissue. Our results demonstrate the novel pharmacological effect that acacetin ameliorates cardiac hypertrophy via Sirt1-mediated activation of AMPK/PGC-1α signal molecules followed by reducing oxidation, inflammation and apoptosis.

Cardiac senescence is alleviated by the natural flavone acacetin via enhancing mitophagy.

Cardiac senescence is associated with cardiomyopathy which is a degenerative disease in the aging process of the elderly. The present study investigates using multiple experimental approaches whether the natural flavone acacetin could attenuate myocardial senescence in C57/BL6 mice and H9C2 rat cardiac cells induced by D-galactose. We found that the impaired heart function in D-galactose-induced accelerated aging mice was improved by oral acacetin treatment in a dose-dependent manner. Acacetin significantly countered the increased serum advanced glycation end products, the myocardial telomere length shortening, the increased cellular senescence marker proteins p21 and p53, and the reduced mitophagy signaling proteins PINK1/Parkin and Sirt6 expression in aging mice. In H9C2 rat cardiac cells, acacetin alleviated cell senescence induced by D-galactose in a concentration-dependent manner. Acacetin decreased p21 and p53 expression, up-regulated PINK1/Parkin, LC3II/LC3I ratio, pLKB1, pAMPK and Sirt6, and reversed the depolarized mitochondrial membrane potential in aging cardiac cells. Mitophagy inhibition with 3-methyladenine or silencing Sirt6 abolished the protective effects of acacetin against cardiac senescence. Further analysis revealed that acacetin effect on Sirt6 was mediated by Sirt1 activation and increase of NAD+/NADH ratio. These results demonstrate that acacetin significantly inhibits in vivo and in vitro cardiac senescence induced by D-galactose via Sirt1-mediated activation of Sirt6/AMPK signaling pathway, thereby enhancing mitophagy and preserving mitochondrial function, which suggests that acacetin may be a drug candidate for treating cardiovascular disorders related to aging.

Uncovered stent insertion for isolated superior mesenteric artery dissection.

ABSTRACT: The aim of this study is to describe our clinical outcomes in isolated superior mesenteric artery dissection (SMAD) patients that underwent uncovered stent insertion.Between January 2016 and August 2019, consecutive isolated SMAD patients at our center were treated via uncovered stent insertion. Both short- and long-term outcomes in these patients were analyzed.Over the course of the study period, 11 total isolated SMAD patients meeting the criteria for stent insertion at our hospital were treated via uncovered stent insertion. Stent placement across the SMAD site was successful in all patients, with 1 stent being used per patient. There were no instances of procedure-related complications, and the median operative duration was 60 minutes. Patency of the distal superior mesenteric artery and branches thereof was achieved in all cases. Patients experienced progressive SMAD-related symptom relief and were followed for 6 to 49 months (median: 22 months). Over this follow-up period, the obliteration of the dissection was observed within 3 months in all patients. We did not detect any instances of stent occlusion, bowel ischemia, or anti-platelet-related bleeding during the follow-up period.Uncovered stent insertion can achieve favorable short- and long-term outcomes in isolated SMAD patients.

Acacetin suppresses the electrocardiographic and arrhythmic manifestations of the J wave syndromes.

BACKGROUND: J wave syndromes (JWS), including Brugada (BrS) and early repolarization syndromes (ERS), are associated with increased risk for life-threatening ventricular arrhythmias. Pharmacologic approaches to therapy are currently very limited. Here, we evaluate the effects of the natural flavone acacetin. METHODS: The effects of acacetin on action potential (AP) morphology and transient outward current (Ito) were first studied in isolated canine RV epicardial myocytes using whole-cell patch clamp techniques. Acacetin's effects on transmembrane APs, unipolar electrograms and transmural ECGs were then studied in isolated coronary-perfused canine RV and LV wedge preparations as well as in whole-heart, Langendorff-perfused preparations from which we recorded a 12 lead ECG and unipolar electrograms. Using floating glass microelectrodes we also recorded transmembrane APs from the RVOT of the whole-heart model. The Ito agonist NS5806, sodium channel blocker ajmaline, calcium channel blocker verapamil or hypothermia (32°C) were used to pharmacologically mimic the genetic defects and conditions associated with JWS, thus eliciting prominent J waves and provoking VT/VF. RESULTS: Acacetin (5-10 µM) reduced Ito density, AP notch and J wave area and totally suppressed the electrocardiographic and arrhythmic manifestation of both BrS and ERS, regardless of the experimental model used. In wedge and whole-heart models of JWS, increasing Ito with NS5806, decreasing INa or ICa (with ajmaline or verapamil) or hypothermia all resulted in accentuation of epicardial AP notch and ECG J waves, resulting in characteristic BrS and ERS phenotypes. Phase 2-reentrant extrasystoles originating from the RVOT triggered VT/VF. The J waves in leads V1 and V2 were never associated with a delay of RVOT activation and always coincided with the appearance of the AP notch recorded from RVOT epicardium. All repolarization defects giving rise to VT/VF in the BrS and ERS models were reversed by acacetin, resulting in total suppression of VT/VF. CONCLUSIONS: We present experimental models of BrS and ERS capable of recapitulating all of the ECG and arrhythmic manifestations of the JWS. Our findings provide definitive support for the repolarization but not the depolarization hypothesis proposed to underlie BrS and point to acacetin as a promising new pharmacologic treatment for JWS.

Doxorubicin cardiomyopathy is ameliorated by acacetin via Sirt1-mediated activation of AMPK/Nrf2 signal molecules.

Doxorubicin cardiotoxicity is frequently reported in patients undergoing chemotherapy. The present study investigates whether cardiomyopathy induced by doxorubicin can be improved by the natural flavone acacetin in a mouse model and uncovers the potential molecular mechanism using cultured rat cardiomyoblasts. It was found that the cardiac dysfunction and myocardial fibrosis induced by doxorubicin were significantly improved by acacetin in mice with impaired Nrf2/HO-1 and Sirt1/pAMPK molecules, which is reversed by acacetin treatment. Doxorubicin decreased cell viability and increased ROS production in rat cardiomyoblasts; these effects are significantly countered by acacetin (0.3-3 µM) in a concentration-dependent manner via activating Sirt1/pAMPK signals and enhancing antioxidation (Nrf2/HO-1 and SOD1/SOD2) and anti-apoptosis. These protective effects were abolished in cells with silencing Sirt1. The results demonstrate for the first time that doxorubicin cardiotoxicity is antagonized by acacetin via Sirt1-mediated activation of AMPK/Nrf2 signal molecules, indicating that acacetin may be a drug candidate used clinically for protecting against doxorubicin cardiomyopathy.

Knowledge and Psychological Stress Related to COVID-19 Among Nursing Staff in a Hospital in China: Cross-Sectional Survey Study.

BACKGROUND: Since December 2019, coronavirus disease (COVID-19) has been rapidly spreading worldwide. Nurses play a key role in fighting this disease and are at risk of COVID-19 infection. Therefore, there is an urgent need to assess the mental health condition of nurses and establish appropriate interventions to reduce the negative psychiatric outcomes of the pandemic. OBJECTIVE: The objectives of this study were to evaluate the knowledge and psychological stress related to COVID-19 among nursing staff and to provide evidence of the need for targeted training and psychological intervention. METHODS: This cross-sectional web-based survey study was performed in a class 3 grade A general hospital in a southwest province of China from March 1 to March 15, 2020. A self-designed questionnaire with questions about COVID-19-related prevention and control knowledge and the Triage Assessment Form (TAF) were used to assess nursing staff's knowledge of COVID-19 and their degree of psychological stress, respectively. SPSS 23.0 was applied for statistical analysis of the collected data. RESULTS: A total of 979 nurses completed the questionnaire. The results showed that the nursing staff provided the fewest correct answers to questions about continuous viral nucleic acid testing specifications (379/979 correct answers, 38.7%), isolation/discharge criteria (539/979 correct answers, 55.1%), and management measures for patients with suspected symptoms (713/979 correct answers, 72.8%). The median total score of the TAF was 7.0 (IQR 5.0-12.0), and there were statistically significant differences in scores between different nursing roles, years of work experience, and hospital departments (P<.05). CONCLUSIONS: This study indicated that nursing staff have insufficient knowledge about COVID-19. Meanwhile, although the psychological damage to nurses during the pandemic was found to be low, nurse managers must continue to monitor the mental health of nursing staff and perform timely interventions.

Acacetin Protects Against High Glucose-Induced Endothelial Cells Injury by Preserving Mitochondrial Function via Activating Sirt1/Sirt3/AMPK Signals.

The strategy of decreasing atherosclerotic cardiovascular disorder is imperative for reducing premature death and improving quality of life in patients with diabetes mellitus. The aim of this study was to investigate whether the natural flavone acacetin could protect against endothelial injury induced by high glucose and attenuate diabetes-accelerated atherosclerosis in streptozotocin-(STZ) induced diabetic ApoE-/- mice model. It was found that in human umbilical vein endothelial cells (HUVECs) cultured with normal 5.5 mM or high 33 mM glucose, acacetin (0.3-3 µM) exerted strong cytoprotective effects by reversing high glucose-induced viability reduction and reducing apoptosis and excess production of intracellular reactive oxygen species (ROS) and malondialdehyde in a concentration-dependent manner. Acacetin countered high glucose-induced depolarization of mitochondrial membrane potential and reduction of ATP product and mitoBcl-2/mitoBax ratio. Silencing Sirt3 abolished the beneficial effects of acacetin. Further analysis revealed that these effects of acacetin rely on Sirt1 activation by increasing NAD+ followed by increasing Sirt3, pAMPK and PGC-1α. In STZ-diabetic mice, acacetin significantly upregulated the decreased signaling molecules (i.e. SOD, Bcl-2, PGC-1α, pAMPK, Sirt3 and Sirt1) in aorta tissue and attenuated atherosclerosis. These results indicate that vascular endothelial protection of acacetin by activating Sirt1/Sirt3/AMPK signals is likely involved in alleviating diabetes-accelerated atherosclerosis by preserving mitochondrial function, which suggests that acacetin may be a drug candidate for treating cardiovascular disorder in patients with diabetes.

Regulation of the TRPC1 channel by endothelin-1 in human atrial myocytes.

BACKGROUND: Our recent study demonstrated that the nonselective cation current mediated by the transient receptor potential canonical 1 (TRPC1) channel is activated by endothelin-1 (ET-1) in human atrial myocytes; however, the related signal molecules involved are unknown. OBJECTIVE: The purpose of this study was to investigate how the TRPC1 channel is regulated by ET-1 and whether it is upregulated in human atria from patients with atrial fibrillation (AF). METHODS: Whole-cell patch technique and molecular biology techniques were used in the study. RESULTS: The ET-1-evoked TRPC1 current was inhibited by the ET-1 type A (ETA) receptor antagonist BQ123 and the ET-1 type B (ETB) receptor antagonist BQ788 as well as the protein kinase C inhibitor chelerythrine. ETA receptor-mediated TRPC1 channel activity was selectively inhibited by the phosphoinositide-3-kinase inhibitor wortmannin, while ETB receptor-mediated TRPC1 activity was inhibited by the phospholipase C inhibitor U73122. The messenger RNAs and proteins of the TRPC1 channel and ETA receptor, but not the ETB receptor, were significantly upregulated in atria from patients with AF. The basal TRPC1 current increased in AF myocytes, and the response to ET-1 was greater in AF myocytes than in sinus rhythm myocytes. ET-1 induced a delayed repolarization in 20% of AF myocytes. CONCLUSION: These results demonstrate for the first time that TRPC1 activation by ET-1 is mediated by protein kinase C through the distinct phospholipids pathways phosphoinositide-3-kinase and phospholipase C and that the TRPC1 channel and ETA receptor are upregulated in AF atria, which are likely involved in atrial electrical remodeling in patients with AF.

Comparative study of carvedilol and quinidine for inhibiting hKv4.3 channel stably expressed in HEK 293 cells.

The inhibition of transient outward potassium current (Ito) is the major ionic mechanism for quinidine to treat Brugada syndrome; however, quinidine is inaccessible in many countries. The present study compared the inhibitory effect of the nonselective ß-adrenergic blocker carvedilol with quinidine on human Kv4.3 (hKv4.3, encoding for Ito) channel and action potential notch using a whole-cell patch technique in HEK 293 cell line expressing KCND3 as well as in ventricular epicardial myocytes of rabbit hearts. It was found that carvedilol and quinidine inhibited hKv4.3 current in a concentration-dependent manner. The IC50 of carvedilol was 1.2 µM for inhibiting hKv4.3 charge area, while the IC50 of quinidine was 2.9 µM (0.2 Hz). Both carvedilol and quinidine showed typical open channel blocking properties (i.e. decreasing the time to peak of activation and increasing the inactivation of hKv4.3), negatively shifted the V1/2 of activation and inactivation, and slowed the recovery from inactivation of the channel. Although carvedilol had weaker in use- and rate-dependent inhibition of hKv4.3 peak current than quinidine, its reduction of the charge area was more than quinidine at all frequencies (0.2-3.3 Hz). Moreover, the inhibitory effect of carvedilol on action potential notch was greater than quinidine. These results provide the novel information that carvedilol, like quinidine, significantly inhibits hKv4.3 and action potential notch, suggesting that carvedilol is likely an alternative drug for preventing malignant ventricular arrhythmias in patients with Brugada syndrome in countries where quinidine is unavailable.

Bradykinin-mediated Ca2+ signalling regulates cell growth and mobility in human cardiac c-Kit+ progenitor cells.

Our recent study showed that bradykinin increases cell cycling progression and migration of human cardiac c-Kit+ progenitor cells by activating pAkt and pERK1/2 signals. This study investigated whether bradykinin-mediated Ca2+ signalling participates in regulating cellular functions in cultured human cardiac c-Kit+ progenitor cells using laser scanning confocal microscopy and biochemical approaches. It was found that bradykinin increased cytosolic free Ca2+ ( Cai2+ ) by triggering a transient Ca2+ release from ER IP3Rs followed by sustained Ca2+ influx through store-operated Ca2+ entry (SOCE) channel. Blockade of B2 receptor with HOE140 or IP3Rs with araguspongin B or silencing IP3R3 with siRNA abolished both Ca2+ release and Ca2+ influx. It is interesting to note that the bradykinin-induced cell cycle progression and migration were not observed in cells with siRNA-silenced IP3R3 or the SOCE component TRPC1, Orai1 or STIM1. Also the bradykinin-induced increase in pAkt and pERK1/2 as well as cyclin D1 was reduced in these cells. These results demonstrate for the first time that bradykinin-mediated increase in free Cai2+ via ER-IP3R3 Ca2+ release followed by Ca2+ influx through SOCE channel plays a crucial role in regulating cell growth and migration via activating pAkt, pERK1/2 and cyclin D1 in human cardiac c-Kit+ progenitor cells.

The Natural Flavone Acacetin Confers Cardiomyocyte Protection Against Hypoxia/Reoxygenation Injury via AMPK-Mediated Activation of Nrf2 Signaling Pathway.

The present study investigates the potential signal pathway of acacetin in cardioprotection against ischemia/reperfusion injury using an in vitro hypoxia/reoxygenation model in primary cultured neonatal rat cardiomyocytes and H9C2 cardiomyoblasts. It was found that acacetin (0.3-3 µM) significantly decreased the apoptosis and reactive oxygen species production induced by hypoxia/reoxygenation injury in cardiomyocytes and H9C2 cardiomyoblasts via reducing the pro-apoptotic proteins Bax and cleaved-caspase-3 and increasing the anti-apoptotic protein Bcl-2. In addition, acacetin not only suppressed the release of pro-inflammatory cytokines TLR-4 and IL-6 induced by hypoxia/reoxygenation injury, but also increased the secretion of anti-inflammatory cytokine IL-10. Moreover, acacetin increased Nrf2 and HO-1 in a concentration-dependent manner, and rescued SOD1 and SOD2 reduction induced by hypoxia/reoxygenation insult. These beneficial effects of acacetin disappeared in cells with silenced Nrf2, suggesting that Nrf2 activation participates in the cardioprotective effect of acacetin against hypoxia/reoxygenation insult. However, acacetin-induced Nrf2 activation was not observed in cells with silenced AMPK and in ventricular tissues of rat hearts treated with the AMPK inhibitor Compound C and subjected to ischemia/reperfusion injury. Our results demonstrate for the first time that AMPK-mediated Nrf2 activation is involved in the cardiomyocytes protection of acacetin against hypoxia/reoxygenation injury by activating a series of intracellular signals involved in anti-oxidation, anti-inflammation, and anti-apoptosis.

Noradrenaline up-regulates volume-regulated chloride current by PKA-independent cAMP/exchange protein activated by cAMP pathway in human atrial myocytes.

BACKGROUND AND PURPOSE: Adrenergic regulation of cell volume-regulated chloride current (ICl.vol ) is species-dependent. The present study investigates the mechanism underlying adrenergic regulation of ICl.vol in human atrial myocytes. EXPERIMENTAL APPROACH: Conventional whole-cell patch voltage-clamp techniques were used to record membrane current in human atrial myocytes. ICl.vol was evoked by hyposmotic bath solution (0.6 times isosmotic, 0.6 T). KEY RESULTS: ICl.vol was augmented by noradrenaline (1 µM) during cell swelling in 0.6 T but not under isosmotic (1 T) conditions. Up-regulation of ICl.vol in 0.6 T was blocked by the ß-adrenoceptor antagonist propranolol (2 µM), but not by the α1 -adrenoceptor antagonist prazosin (2 µM). This ß-adrenergic response involved cAMP but was independent of PKA; the protein kinase inhibitor H-89 (2 µM) or PKI (10 µM in pipette solution) failed to prevent ICl.vol up-regulation by noradrenaline. Moreover, the PI3K/PKB inhibitor LY294002 (50 µM) and the PKG inhibitor KT5823 (10 µM) did not affect noradrenaline-induced increases in ICl.vol . Interestingly, the exchange protein directly activated by cAMP (Epac) agonist 8-pCPT-2'-O-Me-cAMP (50 µM) also up-regulated ICl.vol , and the noradrenaline-induced increase of ICl.vol in 0.6 T was reversed or prevented by the Epac inhibitor ESI-09 (10 µM). CONCLUSION AND IMPLICATIONS: These data show that ICl.vol evoked by cell swelling of human atrial myocytes is up-regulated by noradrenaline via a PKA-independent cAMP/Epac pathway in human atrial myocytes. cAMP/Epac-induced ICl.vol is expected to shorten action potential duration during human atrial myocytes swelling and may be involved in abnormal cardiac electrical activity during cardiac pathologies that evoke ß-adrenoceptor signalling.

A study on the preparation and application of a core-shell surface imprinted uranyl magnetic chelating adsorbent.

A core-shell surface imprinted uranyl magnetic chelating adsorbent (UMCA) was synthesized by combining the sol-gel process with the surface molecular imprinting technique (SMIT). A specific salophen and uranyl-salophen were designed and synthesized. Then, the synthesized uranyl-salophen complex was used as a template (in which uranyl is the target analyte), 3-aminopropyltriethoxysilane as a functional monomer and tetraethylorthosilicate as a cross-linker. The obtained UMCA was characterized by a variety of modern analytical and detection techniques. The adsorbent can be used for the solid-phase extraction of uranyl with good selectivity, high adsorption capacity, magnetic separation characteristics and good reusability. The chelating sorbent was successfully applied for the separation of uranyl, followed by multiphase photocatalytic resonance fluorescence method determination in several environmental water samples with a relative standard deviation of <5.48% and spiked recoveries of 92.5% to 103.0%. The adsorption mechanism was preliminarily discussed.

The Natural Flavone Acacetin Blocks Small Conductance Ca2+-Activated K+ Channels Stably Expressed in HEK 293 Cells.

The natural flavone acacetin inhibits several voltage-gated potassium currents in atrial myocytes, and has anti-atrial fibrillation (AF) effect in experimental AF models. The present study investigates whether acacetin inhibits the Ca2+-activated potassium (KCa) currents, including small conductance (SKCa1, SKCa2, and SKCa3), intermediate conductance (IKCa), and large-conductance (BKCa) channels stably expressed in HEK 293 cells. The effects of acacetin on these KCa channels were determined with a whole-cell patch voltage-clamp technique. The results showed that acacetin inhibited the three subtype SKCa channel currents in concentration-dependent manner with IC50 of 12.4 µM for SKCa1, 10.8 µM for SKCa2, and 11.6 µM for SKCa3. Site-directed mutagenesis of SKCa3 channels generated the mutants H490N, S512T, H521N, and A537V. Acacetin inhibited the mutants with IC50 of 118.5 µM for H490N, 275.2 µM for S512T, 15.3 µM for H521N, and 10.6 µM for A537V, suggesting that acacetin interacts with the P-loop helix of SKCa3 channel. However, acacetin at 3-10 µM did not decrease, but induced a slight increase of BKCa (+70 mV) by 8% at 30 µM. These results demonstrate the novel information that acacetin remarkably inhibits SKCa channels, but not IKCa or BKCa channels, which suggests that blockade of SKCa by acacetin likely contributes to its anti-AF property previously observed in experimental AF.