Inhibitory effect of DIDS, NPPB, and phloretin on intracellular chloride channels

Cao

et al. 2008

Cell Physiol Biochem

Aims: 4,4''-diisothiocyanostilbene-2,2''-disulfonic acid (DIDS), a non-selective chloride channel blocker, has been shown to prevent cell apoptosis, however, the underlying mechanisms remain undefined, thus the present study was to explore whether phosphatidylinositol 3''-kinase (PI3K)/Akt and its downstream molecules are involved in the cytoprotective effect of DIDS. Methods: Neonatal rat cardiomyocytes were exposed to staurosporine (STS) in the presence or absence of DIDS. Cell viability, apoptosis and expressions of Akt, phospho-Akt (p-Akt), eNOS, phospho-eNOS (p-eNOS), Bcl-2/Bax and nitric oxide (NO) production were determined, and Bax translocation was assessed by double immunofluorescence labeling and Western blotting. Results: DIDS markedly improved cell viability and exerted an anti-apoptotic effect on STS-exposed cardiomyocytes. DIDS resulted in a 2.1-fold increase of p-Akt over control levels, prevented the reduction in eNOS expression and phospho-eNOS levels induced by STS and significantly increased NO production (all P<0.01 vs. STS alone). Treatment with LY294002, a selective PI3K inhibitor, abolished DIDS-induced increases in p-Akt, eNOS, p-eNOS and NO production, and completely abrogated the DIDS-induced anti-apoptotic effect (P<0.01). Treatment with L-NAME, a non-selective NOS inhibitor similarly inhibited the increased NO but only partly abolished protective effects of DIDS (P<0.05). In addition, DIDS effectively inhibited STS-induced Bax translocation to mitochondria, which was also reversed by LY294002. Conclusion: DIDS protects cardiomyocytes against STS-induced apoptosis via activating PI3K/Akt signaling pathway, including increasing eNOS phosphorylation and the subsequent NO production and inhibiting Bax translocation.

Section: Discussionsupporting

confidence: 87%

DIDS Attenuates Staurosporine-induced Cardiomyocyte Apoptosis by PI3K/Akt Signaling Pathway: Activation of eNOS/NO and Inhibition of Bax Translocation

Cao

et al. 2008

Cell Physiol Biochem

“…It was reported that procyanidins induces necrosis and apoptosis of prostate cancer cell 'PC-3' for 6 and 24 hr with different concentration (100-300 µg ml -1 ) of procyanidins (Shang et al 2009). Studies also revealed the apoptotic and cardioprotective properties of phloretin on H 2 O 2 -induced primary culture (Malekova et al 2007). Phloretin demonstrated strong anti-tumor effects by inhibiting the growth of several cancer cell lines (Kobori et al 1999).…”

Section: Biological Properties Of Apple Phenolicsmentioning

confidence: 97%

Apple phenolics as nutraceuticals: assessment, analysis and application

Rana

Bhushan

2015

J Food Sci Technol

Humankind is presently engulfed by convenience quench, modern life style and urbanized diet system leading to progression in array of health disorders. The past decade confronted cardiometabolic disorder (21.8 %), lower respiratory and chronic obstructive lung disease (12.5 %) as the major causes of death world over. In anticipation, scientific communities' have demonstrated the role of healthy diets, especially those rich in fruits and vegetables, for management of such health related issues. These horticultural crops are considered as a good source of polyphenols such as dihydrochalcones, flavanols, flavonols, anthocyanins and phenolic acids. The present article reviews the efforts made to assess the potential of apple phenolic compounds present in fresh fruits, leaves, bark and pomace as dietary polyphenols. Considering the positive impact of such phytochemicals on human health, various nutraceuticals, dietary supplements and phenolic-rich food products are presently available on market shelves. On analytical front, improved instrumentation based on liquid chromatography (HPLC, UPLC, LC/MS/ MS) have made the assessment of phenolics more rapid and reliable. Thus, owing to the emergent interest in natural compounds, it is pertinent to discuss the latest significant research findings on therapeutic aspects along with probable metabolic mechanisms of dietary polyphenols found in apples and their implications on human health.

“…Phloretin (2',4',6'-trihydroxy-3-(4-hydroxyphenyl)-propiophenone), a component of apples, pears and strawberries [1,2], is a dipolar small molecule interfering with diverse channels and transporters [3,4,5,6,7,8,9,10] including glucose transporters [1,2]. Effects of Phloretin include decrease of oxidative stress [11], inhibition of inflammation [12], increase endothelial nitric oxide production and vasodilation [13,14], downregulation of endothelial adhesion molecules [15], and inhibition of platelet activation [15].…”

Section: Introductionmentioning

confidence: 99%

Stimulation of Erythrocyte Death by Phloretin

Bissinger

Fischer

Jilani

et al. 2014

Cell Physiol Biochem

Background: Phloretin, a natural component of apples, pears and strawberries, has previously been shown to stimulate apoptosis of nucleated cells. Erythrocytes may similarly enter suicidal death or eryptosis, which is characterized by cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane with phosphatidylserine translocation to the erythrocyte surface. Stimulators of eryptosis include increase of cytosolic Ca²⁺-activity ([Ca²⁺]_i), ceramide, ATP depletion, and activation of protein kinase C (PKC) as well as p38 mitogen activated protein kinase (p38 kinase). Methods: Phosphatidylserine exposure at the cell surface was estimated from annexin V binding, cell volume from forward scatter, [Ca²⁺]_i from Fluo3-fluorescence, and ceramide abundance from binding of specific antibodies. Results: A 48 h exposure of human erythrocytes to phloretin significantly increased the percentage of annexin-V-binding cells (≥100 µM) without significantly influencing forward scatter. Phloretin did not significantly modify [Ca²⁺]_i and the stimulation of annexin-V-binding by phloretin (300 µM) did not require presence of extracellular Ca²⁺. Phloretin did not significantly modify erythrocyte ATP levels, and the effect of phloretin on annexin-V-binding was not significantly altered by PKC inhibitor staurosporine (1 µM) or p38 kinase inhibitor SB2203580 (2 µM). However, phloretin significantly increased the ceramide abundance at the cell surface. Conclusions: Phloretin stimulates phospholipid scrambling of the erythrocyte cell membrane, an effect at least partially due to up-regulation of ceramide abundance.