Disruption of calcium homeostasis by cardiac-specific over-expression of PPAR-γ in mice: A role in ventricular arrhythmia

Yang

et al. 2018

Cell Physiol Biochem

Background/Aims: Total saponins of Aralia elata (Miq) Seem (AS) from the Chinese traditional herb Long ya Aralia chinensis L. reportedly provide cardioprotective effects, but the exact mechanisms require further study. Previous studies have showed that myocardial ischemia/ reperfusion injury (MIRI) was related to calcium homeostasis imbalance and endoplasmic reticulum stress (ERS). Thus, this study aimed to demonstrate protective effects of AS on MIRI. Methods: After administrating AS for 5 days, the left anterior descending artery coronary artery of Sprague-Dawley (SD) rats was ligated for 30 min. After 48 h of reperfusion, haemodynamics, Evans blue/ 2,3,5-triphenyltetrazolium chloride (TTC) staining, hematoxylin-eosin (HE) staining, masson staining and the levels of lactate dehydrogenase (LDH) and creatine kinase (CK), superoxide dismutase (SOD), malondialdehyde (MDA) were detected to assess MIRI. ATPase activity and Western Blot were used to study the mechanisms. Results: Compared with IR group, AS treatment groups could significantly reduce myocardial infarct size; improve myocardial pathologic progress; decrease content of LDH, CK, and MDA; increase content of SOD; and restore the activities of Ca²⁺-Mg²⁺-ATPase, Na⁺-K⁺-ATPase, sarcoplasmic reticulum Ca²⁺-ATPases (SERCA), and calcineurin (CaN). AS treatment groups also significantly up-regulated the expression of GRP78, C/EBP homologous protein (CHOP), and Bax, and down-regulated the expression of Bcl-2, all similar to the effects of ERS. Conclusion: These findings illustrated that AS could prevent myocardial ischemia/reperfusion injury and reduce calcium homeostasis imbalance and ERS-related apoptosis.

“…Calcium overload is considered as a critical factor of initiating MIRI [32,33]. Therefore, we detected some ATPase activities associated with calcium to determine their relationship.…”

Section: Discussionmentioning

confidence: 99%

Total Saponins of Aralia Elata (Miq) Seem Alleviate Calcium Homeostasis Imbalance and Endoplasmic Reticulum Stress-Related Apoptosis Induced by Myocardial Ischemia/Reperfusion Injury

Yang

et al. 2018

Cell Physiol Biochem

“…The human cardiomyocyte cell line AC16 was kindly supplied by Drs. Yangxin Chen and Yong Xie, Sun Yat-sen Memorial Hospital [ 11 ]. Cells were maintained in DMEM supplied with 10% FBS and 1% antibiotic solution.…”

Section: Methodsmentioning

confidence: 99%

ISL1 overexpression enhances the survival of transplanted human mesenchymal stem cells in a murine myocardial infarction model

et al. 2018

BackgroundThe LIM-homeobox transcription factor islet-1 (ISL1) has been proposed as a marker for cardiovascular progenitor cells. This study investigated whether forced expression of ISL1 in human mesenchymal stem cells (hMSCs) improves myocardial infarction (MI) treatment outcomes.MethodsThe lentiviral vector containing the human elongation factor 1α promoter, which drives the expression of ISL1 (EF1α-ISL1), was constructed using the Multisite Gateway System and used to transduce hMSCs. Flow cytometry, immunofluorescence, Western blotting, TUNEL assay, and RNA sequencing were performed to evaluate the function of ISL1-overexpressing hMSCs (ISL1-hMSCs).ResultsThe in vivo results showed that transplantation of ISL1-hMSCs improved cardiac function in a rat model of MI. Left ventricle ejection fraction and fractional shortening were greater in post-MI hearts after 4 weeks of treatment with ISL1-hMSCs compared with control hMSCs or phosphate-buffered saline. We also found that ISL1 overexpression increased angiogenesis and decreased apoptosis and inflammation. The greater potential of ISL1-hMSCs may be attributable to an increased number of surviving cells after transplantation. Conditioned medium from ISL1-hMSCs decreased the apoptotic effect of H2O2 on the cardiomyocyte cell line H9c2. To clarify the molecular basis of this finding, we employed RNA sequencing to compare the apoptotic-related gene expression profiles of control hMSCs and ISL1-hMSCs. The results showed that insulin-like growth factor binding protein 3 (IGFBP3) was the only gene in ISL1-hMSCs with a RPKM value higher than 100 and that the difference fold-change between ISL1-hMSCs and control hMSCs was greater than 3, suggesting that IGFBP3 might play an important role in the anti-apoptosis effect of ISL1-hMSCs through paracrine effects. Furthermore, the expression of IGFBP3 in the conditioned medium from ISL1-hMSCs was almost fourfold greater than that in conditioned medium from control hMSCs. Moreover, the IGFBP3 neutralization antibody reversed the apoptotic effect of ISL1-hMSCs-CM.ConclusionsThese results suggest that overexpression of ISL1 in hMSCs promotes cell survival in a model of MI and enhances their paracrine function to protect cardiomyocytes, which may be mediated through IGFBP3. ISL1 overexpression in hMSCs may represent a novel strategy for enhancing the effectiveness of stem cell therapy after MI.Electronic supplementary materialThe online version of this article (10.1186/s13287-018-0803-7) contains supplementary material, which is available to authorized users.

“…Ashrafi et al also reported increased mRNA levels of SERCA2a after 8 weeks in high fat diet fed rats (Ashrafi et al, 2016). While Leopoldo et al, found no change in protein expression after 8 weeks (Leopoldo et al, 2011), several other studies showed increased protein expression consistent with increased SERCA2a activity in ventricular myocytes (Xie et al, 2016). In a DIO Psammomys obesus Gerbil model, Sahraoui et al found that mRNA and protein expression levels of SERCA2a decreased after 16 weeks (Sahraoui et al, 2016).…”

Section: Voltage-gated L-type Ca Channels (Ica L) Ca Handling Protementioning

confidence: 97%

Cardiac Ion Channel Regulation in Obesity and the Metabolic Syndrome: Relevance to Long QT Syndrome and Atrial Fibrillation

Aromolaran

Boutjdir

2017

Front. Physiol.

Obesity and its associated metabolic dysregulation leading to metabolic syndrome is an epidemic that poses a significant public health problem. More than one-third of the world population is overweight or obese leading to enhanced risk of cardiovascular disease (CVD) incidence and mortality. Obesity predisposes to atrial fibrillation, ventricular, and supraventricular arrhythmias; conditions that are underlain by dysfunction in electrical activity of the heart. To date, current therapeutic options for cardiomyopathy of obesity are limited, suggesting that there is considerable room for development of therapeutic interventions with novel mechanisms of action that will help normalize rhythm in obese patients. Emerging candidates for modulation by obesity are cardiac ion channels and Ca handling proteins. However, the underlying molecular mechanisms of the impact of obesity on these channels/Ca handling proteins remain incompletely understood. Obesity is marked by accumulation of adipose tissue associated with a variety of adverse adaptations including dyslipidemia (or abnormal levels of serum free fatty acids), increased secretion of pro-inflammatory cytokines, fibrosis, hyperglycemia, and insulin resistance, that will cause electrical remodeling and thus predispose to arrhythmias. Further, adipose tissue is also associated with the accumulation of subcutaneous and visceral fat, which are marked by distinct signaling mechanisms. Thus, there may also be functional differences in the outcome of regional distribution of fat deposits on ion channel/Ca handling proteins expression. Evaluating alterations in their functional expression in obesity will lead to progress in the knowledge about the mechanisms responsible for obesity-related arrhythmias. These advances are likely to reveal new targets for pharmacological modulation. The objective of this article is to review cardiac ion channel/Ca handling proteins remodeling that predispose to arrhythmias. Understanding how obesity and related mechanisms lead to cardiac electrical remodeling is likely to have a significant medical and economic impact.