Berberine inhibits norepinephrine-induced apoptosis in neonatal rat cardiomyocytes via inhibiting ROS-TNF-α-caspase signaling pathway

Milrinone effects on cardiac mitochondria, hemodynamics, and death in catecholamine-infused rats

BACKGROUND

Catecholamine-storm is considered the major cause of enterovirus 71-associated cardiopulmonary death. To elucidate the effect of milrinone on cardiac mitochondria and death, a rat model of catecholamine-induced heart failure was investigated.

METHODS

Young male Spray-Dawley rats received a continuous intravenous infusion of norepinephrine then followed by co-treatment with and without milrinone or esmolol. Vital signs were monitored and echocardiography was performed at indicated time points. At the end of experiments, hearts were extracted to study mitochondrial function, biogenesis, and DNA copy numbers.

RESULTS

Hypernorepinephrinemia induced persistent tachycardia, hypertension, and high mortality and significantly impaired the activities of the electron transport chain and suppressed mitochondrial DNA copy number, mitochondrial transcription factor A and peroxisome proliferator-activated receptor-gamma coactivator 1-α. Norepinephrine-induced hypertension could be significantly suppressed by milrinone and esmolol. Milrinone improved but esmolol deteriorated the survival rate. The left ventricle was significantly enlarged shortly after norepinephrine infusion but later gradually reduced in size by milrinone. The impairment and suppression of mitochondrial function could be significantly reversed by milrinone but not by esmolol.

CONCLUSIONS

Milrinone may protect the heart via maintaining mitochondrial function from hypernorepinephrinemia. This study warrants the importance of milrinone and the preservation of mitochondrial function in the treatment of catecholamine-induced death.

IMPACT

Milrinone may protect the heart from hypernorepinephrinemia-induced death via maintaining myocardial mitochondrial activity, function, and copy number. Maintenance of cardiac mitochondrial function may be a potential therapeutic strategy in such catecholamine-induced heart failure.

The cellular function and molecular mechanism of formaldehyde in cardiovascular disease and heart development

As a common air pollutant, formaldehyde is widely present in nature, industrial production and consumer products. Endogenous formaldehyde is mainly produced through the oxidative deamination of methylamine catalysed by semicarbazide-sensitive amine oxidase (SSAO) and is ubiquitous in human body fluids, tissues and cells. Vascular endothelial cells and smooth muscle cells are rich in this formaldehyde-producing enzyme and are easily damaged owing to consequent cytotoxicity. Consistent with this, increasing evidence suggests that the cardiovascular system and stages of heart development are also susceptible to the harmful effects of formaldehyde. Exposure to formaldehyde from different sources can induce heart disease such as arrhythmia, myocardial infarction (MI), heart failure (HF) and atherosclerosis (AS). In particular, long-term exposure to high concentrations of formaldehyde in pregnant women is more likely to affect embryonic development and cause heart malformations than long-term exposure to low concentrations of formaldehyde. Specifically, the ability of mouse embryos to effect formaldehyde clearance is far lower than that of the rat embryos, more readily allowing its accumulation. Formaldehyde may also exert toxic effects on heart development by inducing oxidative stress and cardiomyocyte apoptosis. This review focuses on the current progress in understanding the influence and underlying mechanisms of formaldehyde on cardiovascular disease and heart development.

Upregulated miRNA-182-5p expression in tumor tissue and peripheral blood samples from patients with non-small cell lung cancer is associated with downregulated Caspase 2 expression

Lung cancer has the highest morbidity and mortality rates among all malignant tumors worldwide. Previous studies demonstrated that microRNA (miR)-182-5p may serve different roles in different types of cancer, including renal cell carcinoma and liver cancer. However, the functional role of miR-182-5p in non-small cell lung cancer (NSCLC) remains unknown. In the current study, the expression level of miR-182-5p in tumor tissue and peripheral blood samples obtained from patients with NSCLC was examined. The biological function of miR-182-5p on NSCLC cell proliferation was also investigated. Tissue and adjacent normal tissue samples were collected from 33 patients with NSCLC. In addition, peripheral blood samples were obtained from patients with NSCLC and 26 healthy control patients. The NSCLC cell line H1299 was used for all functional assays. Reverse transcription-quantitative polymerase chain reaction was used to determine the miR-182-5p or Caspase 2 (CASP2) mRNA expression levels in NSCLC tissue and peripheral blood samples, as well as in the NSCLC cell line. Western blotting was used to examine the protein expression level of CASP2 in tissue samples and cells, and ELISA was performed to measure the protein level of CASP2 in peripheral blood samples. MTT assay was performed to examine NSCLC cell proliferation. Flow cytometry was used to detect apoptosis. Dual-luciferase reporter assay was used to examine whether miRN182-5p directly interacts with CASP2. The current study demonstrated that miR-182-5p expression was upregulated in NSCLC tissue and peripheral blood samples from patients with NSCLC, which suggests that miR-182-5p, may serve a functional role in NSCLC. In addition, inhibition of miR-182-5p expression suppressed cell proliferation and enhanced cell apoptosis in NSCLC cells. CASP2 expression was downregulated in NSCLC tissue and peripheral blood samples from patients with NSCLC. The current study demonstrated that miR-182-5p may regulate NSCLC cell proliferation and apoptosis by regulating CASP2 expression as miR-182-5p directly binds with the 3′-untranslated region of CASP2, thereby regulating CASP2 expression.

Berberine-Promoted CXCR4 Expression Accelerates Endothelial Repair Capacity of Early Endothelial Progenitor Cells in Persons with Prehypertension

OBJECTIVE

To evaluate whether the berberine treatment can improve endothelial repair capacity of early endothelial progenitor cells (EPCs) from prehypertensive subjects through increasing CXC chemokine receptor 4 (CXCR4) signaling.

METHODS

EPCs were isolated from prehypertensive and healthy subjects and cultured. In vivo reendothelialization capacity of EPCs from prehypertensive patients with or without in vitro berberine treatment was examined in a nude mouse model of carotid artery injury. The protein expressions of CXCR4/Janus kinase-2 (JAK-2) signaling of in vitro EPCs were detected by Western blot analysis.

RESULTS

CXCR4 signaling and alteration in migration and adhesion functions of EPCs were evaluated. Basal CXCR4 expression was significantly reduced in EPCs from prehypertensive patients compared with normal subjects (P<0.01). Also, the phosphorylation of JAK-2 of EPCs, a CXCR4 downstream signaling, was significantly decreased (P<0.01). Berberine promoted CXCR4/JAK-2 signaling expression of in vitro EPCs (P<0.01). Transplantation of EPCs pretreated with berberine markedly accelerated in vivo reendothelialization (P<0.01). The increased in vitro function and in vivo reendothelialization capacity of EPCs were inhibited by CXCR4 neutralizing antibody or pretreatment with JAK-2 inhibitor AG490, respectively (P<0.01).

CONCLUSION

Berberinemodified EPCs via up-regulation of CXCR4 signaling contributes to enhanced endothelial repair capacity in prehypertension, indicating that berberine may be used as a novel potential primary prevention means against prehypertension-related atherosclerotic cardiovascular disease.

Berberine nanoparticles protects tubular epithelial cells from renal ischemia-reperfusion injury

Renal ischemia-reperfusion (I/R) injury is one of the most common causes of acute renal failure, the prognosis of which remains poor and there still lacks of effective therapeutics available in the clinic. This study aimed at investigating the effects of Berberine nanoparticles (BBR-NP) on the ischemia-reperfusion injury of renal tubular epithelial cells and underlying the mechanisms. Our results showed that in a rat model of renal I/R injury, BBR and BBR-NP protected renal against injury both functionally (as assessed by serum urea nitrogen and creatinine level) and morphologically (as assessed by HE staining, transmission electron microscopy and TUNEL staining) in a dose-dependent manner, with the effects of BBR-NP superior to BBR alone. Mechanism investigation showed that BBR-NP reversed oxidative stress and subsequent apoptosis of renal cells, as demonstrated by the decreased expression of proteins involved in the oxidative stress and mitochondrial stress pathways. In conclusion, our study showed that BBR-NP is superior to BBR alone in protecting renal against I/R injury and explored the underlying mechanisms, which should be tested in further studies and might give impetus to the development of novel therapeutics based on BBR-NP against renal I/R.

Protective effect of berberine on doxorubicin‑induced acute hepatorenal toxicity in rats

Doxorubicin (DOX), a potent broad‑spectrum chemotherapeutic agent used for the treatment of several types of cancer, is largely limited due to its serious side effects on non‑target organs. Thus, the present study aimed to investigate whether berberine (Ber), an isoquinoline alkaloid, could reduce DOX‑induced acute hepatorenal toxicity in rats. Fifty rats were randomly divided into five groups: i) Control group, ii) DOX group, iii) DOX+Ber (5 mg kg) group; iv) DOX+Ber (10 mg kg), and v) DOX+Ber (20 mg kg) group. In the tests, body weight, organ index, general condition and mortality were observed. In addition, the serum levels of alanine transaminase (ALT), aspartate aminotransferase (AST), total cholesterol (TCHO) and blood urea nitrogen (BUN) were determined to evaluate hepatorenal function. Hepatorenal toxicity was further assessed using hematoxylin and eosin stained sections. Furthermore, the levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and malondialdehyde (MDA) in rat serum or tissue homogenate were also assessed to determine the mechanisms of action. Results suggested that pretreatment with Ber ameliorated the DOX‑induced liver and kidney injury by lowering the serum ALT, AST, TCHO and BUN levels, and the damage observed histologically, such as hemorrhage and focal necrosis of liver and kidney tissues induced by DOX were also attenuated by Ber. Furthermore, Ber also exerted certain antioxidative properties through reversing the changes in the levels of MDA, SOD, GSH and MDA induced by DOX. These findings indicate that Ber has protective effects against DOX‑induced acute hepatorenal toxicity in rats. Combination of Ber with DOX is a novel strategy that has the potential for protecting against DOX‑induced hepatorenal toxicity in clinical practice.

Antioxidative effect of luteolin pretreatment on simulated ischemia/reperfusion injury in cardiomyocyte and perfused rat heart

OBJECTIVE

To investigate the antioxidative effect and mechanism of luteolin on rat cardiomyocytes and isolated hearts followed by simulated ischemia/reperfusion (SI/R) injury.

METHODS

The left ventricular cardiomyocytes and the isolated hearts from adult rats were subjected to SI/R injury. The experiment groups included control, SI/R, luteolin + SI/R (Lut + SI/R), vitamin E (Vit E) + SI/R, and LY294002 + luteolin + SI/R (LY + Lut + SI/R) groups. Cell viability, shortening amplitude, lactate dehydrogenase (LDH) release, superoxide dismutase (SOD) activity, the production of reactive oxygen species (ROS) and malondialdehyde (MDA), expression levels of Akt, phosphorylated Akt, NOX2 (gp91phox), NOX2 mRNA, mitogen-activated protein kinase (p38 MAPK) and phosphorylated p38MAPK were all measured after 3-h simulated ischemia and 2-h simulated reperfusion procedure in cardiomyocytes. Vit E was used as a standard control. The contractile function of isolated hearts was further observed after they were subjected to 30-min global ischemia and 120-min reperfusion.

RESULTS

Pretreatment with 8-μmol/L luteolin substantially increased cell viability and shortening amplitude, while reducing evidence of oxidative stress-induced damage in the cells. In addition, the expression of NOX2, NOX2 mRNA and phosphorylation of p38MAPK were all downregulated. Furthermore, pretreatment with 40-μmol/L luteolin improved the recovery of myocardial contractile function following SI/R-induced injury, and luteolin markedly increased phosphorylation of Akt. However, all of the above effects were partially inhibited by the phosphatidylinositol 3-kinase (PI3K) inhibitor, LY294002.

CONCLUSIONS

Luteolin prevents SI/R-induced myocardial damage by reducing oxidative stress-induced injury in isolated rat hearts and cardiomyocytes, and the cardioprotection induced by luteolin was partially mediated by the PI3K/Akt pathway.

Berberine Attenuates Myocardial Ischemia/Reperfusion Injury by Reducing Oxidative Stress and Inflammation Response: Role of Silent Information Regulator 1

Berberine (BBR) exerts potential protective effect against myocardial ischemia/reperfusion (MI/R) injury. Activation of silent information regulator 1 (SIRT1) signaling attenuates MI/R injury by reducing oxidative damage and inflammation response. This study investigated the antioxidative and anti-inflammatory effects of BBR treatment in MI/R condition and elucidated its potential mechanisms. Sprague-Dawley rats were treated with BBR in the absence or presence of the SIRT1 inhibitor sirtinol (Stnl) and then subjected to MI/R injury. BBR conferred cardioprotective effects by improving postischemic cardiac function, decreasing infarct size, reducing apoptotic index, diminishing serum creatine kinase and lactate dehydrogenase levels, upregulating SIRT1, Bcl-2 expressions, and downregulating Bax and caspase-3 expressions. Stnl attenuated these effects by inhibiting SIRT1 signaling. BBR treatment also reduced myocardium superoxide generation, gp91^phox expression, malondialdehyde (MDA) level, and cardiac inflammatory markers and increased myocardium superoxide dismutase (SOD) level. However, these effects were also inhibited by Stnl. Consistently, BBR conferred similar antioxidative and anti-inflammatory effects against simulated ischemia reperfusion injury in cultured H9C2 cardiomyocytes. SIRT1 siRNA administration also abolished these effects. In summary, our results demonstrate that BBR significantly improves post-MI/R cardiac function recovery and reduces infarct size against MI/R injury possibly due to its strong antioxidative and anti-inflammatory activity. Additionally, SIRT1 signaling plays a key role in this process.

The neuroprotective effect of berberine in mercury-induced neurotoxicity in rats

The central nervous system is one of the most vulnerable organs affected by mercury toxicity. Both acute and chronic exposure to mercury is also known to cause a variety of neurological or psychiatric disorders. Here, the neuroprotective effect of berberine (BN; 100 mg/kg bwt) on mercuric chloride (HgCl2; 0.4 mg/kg bwt) induced neurotoxicity and oxidative stress was examined in rats. Adult male albino Wistar rats were injected with HgCl2 for 7 days. HgCl2 treatment induced oxidative stress by increasing lipid peroxidation (LPO) and nitrite/nitrate (nitric oxide; NO) production along with a concomitant decrease in glutathione (GSH) and various antioxidant enzymes, namely superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase. Pre-treatment of rats with BN inhibited LPO and NO production, whereas it increased GSH content. Activities of antioxidant enzymes were also restored concomitantly when compared to the control rats after BN administration. Berberine also caused decrease in TNF-α level and caspase-3 activity which was higher with HgCl2. Furthermore, treatment with BN inhibited apoptosis, as indicated by the reduction of Bax/Bcl-2 ratio in brain tissue. These data indicated that BN augments antioxidant defense with anti-inflammatory and anti-apoptotic activities against HgCl2-induced neurotoxicity and provides evidence that it has a therapeutic potential as neuroprotective agent.

Mechanical Stretch Induces Apoptosis Regulator TRB3 in Cultured Cardiomyocytes and Volume-Overloaded Heart

The expression of TRB3 (tribbles 3), an apoptosis regulated gene, increases during endoplasmic reticulum (ER) stress. How mechanical stress affects the regulation of TRB3 in cardiomyocytes during apoptosis is not fully understood. An in vivo model of aorta-caval shunt in adult rats demonstrated the increased TRB3 protein expression in the myocardium. The tumor necrosis factor-alpha (TNF-α) antagonist etanercept reversed the TRB3 protein expression and cardiomyocyte apoptosis induced by AV shunt. An in vitro model of cyclic stretch in neonatal rats was also used to investigate TRB3 expression. We hypothesized that cardiomyocyte apoptosis induced by cyclic stretch is TRB3 dependent. Neonatal rat cardiomyocytes grown on a flexible membrane base were stretched by vacuum to 20% of maximum elongation, at 60 cycles/min. Cyclic stretch significantly increased TRB3 protein and mRNA expression. Addition of c-jun N-terminal kinase (JNK) inhibitor SP600125, TNF-α antibody and etanercept 30 min before stretch reversed the induction of TRB3 protein induced by stretch. Cyclic stretch induced the DNA-binding activity of growth arrest and DNA damaged inducible gene-153 (GADD153) by electrophoretic mobility shift assay. SP600125, JNK siRNA, TNF-α antibody and etanercept abolished the binding activity induced by stretch. TRB3 promoter activity was enhanced by stretch and TRB3-mut plasmid, SP600125, TNF-α antibody and etanercept attenuated TRB3 promoter activity induced by stretch. Exogenous administration of TNF-α recombinant protein to the non-stretched cardiomyocytes increased TRB3 protein expression similar to that seen after stretch. Cyclic stretch induced cardiomyocyte apoptosis is inhibited by TRB3 siRNA and etanercept. The stretch-induced TRB3 is mediated by TNF-α、JNK and GADD153 pathway. These results indicate that TRB3 plays an important role in stretch-induced cardiomyocyte apoptosis.

β₁-adrenoceptor stimulation promotes LPS-induced cardiomyocyte apoptosis through activating PKA and enhancing CaMKII and IκBα phosphorylation

INTRODUCTION

Caspase activation and cardiomyocyte apoptosis have been implicated in lipopolysaccharide (LPS)-induced cardiac contractile dysfunction. We have recently demonstrated that β1-adrenoceptor (AR) activation by endogenous norepinephrine contributes to cardiomyocyte apoptosis in endotoxemic mice. Here, we further investigated the molecular mechanisms for the enhancing effect of β₁-AR activation on LPS-induced cardiomyocyte apoptosis.

METHODS

The adult mouse ventricular myocytes were exposed to LPS, dobutamine, protein kinase A (PKA) inhibitor or/and nifedipine, an L-type Ca(2+) channel blocker. Male BALB/c mice were treated with LPS or/ and β₁-AR antagonist, atenolol. Cardiomyocyte apoptosis was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling (TUNEL) assay and apoptosis-associated molecules were detected.

RESULTS

LPS induced apoptosis in adult mouse ventricular myocytes, dobutamine (DOB), a β₁-AR agonist, promoted apoptosis, caspase-8, 9 and 3 activation and increased cytosolic Ca(2+) concentration in LPS-challenged cardiomyocytes. DOB also up-regulated TNF-α expression, decreased Bcl-2 levels, promoted Bax translocation to mitochondria, mitochondrial membrane potential loss and cytochrome c release as well as IκBα, p38 MAPK, JNK and Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) phosphorylation in LPS-treated cardiomyocytes. PKA inhibitor abolished the effects of DOB on caspase-9 activation, Bcl-2 levels as well as JNK and p38 MAPK phosphorylation, but not on IκBα phosphorylation, TNF-α expression and caspase-8 activation in LPS-stimulated cardiomyocytes. Pretreatment with nifedipine not only significantly blocked the enhancing effects of DOB on LPS-induced elevation in cytosolic Ca(2+) concentration and CaMKII phosphorylation in cardiomyocytes, but also partly reversed the effects of DOB on caspase-9 and caspase-3/7 activities in LPS-treated cardiomyocytes. Furthermore, atenolol suppressed TNF-α expression, JNK, p38 MAPK and CaMKII phosphorylation, increased Bcl-2 expression, and inhibited cytochrome c release and cardiomyocyte apoptosis in the myocardium of endotoxemic mice.

CONCLUSIONS

β1-AR activation promotes LPS-induced apoptosis through activating PKA, increasing CaMKII phosphorylation as well as enhancing IκBα phosphorylation and TNF-α expression in cardiomyocytes.