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Regulation of Osmolytes Syntheses and Improvement of Abiotic Stress Tolerance in Plants
Published in Hasanuzzaman Mirza, Nahar Kamrun, Fujita Masayuki, Oku Hirosuke, Tofazzal M. Islam, Approaches for Enhancing Abiotic Stress Tolerance in Plants, 2019
Ambuj Bhushan Jha, Pallavi Sharma
Thiery et al. (2004) reported the possible role of phospholipase D besides calcium and ABA for the regulation of proline synthesis. Proline accumulation is negatively controlled by phospholipase D under non-stressed conditions (Knight et al., 1997; Parre et al., 2007). Phospholipase D itself has been suggested to be regulated by calcium. The data also indicated that the application of primary butyl alcohols enhanced the proline responsiveness of seedlings to mild hyperosmotic stress. Higher proline responsiveness was observed to hyperosmotic stress when phospholipase D was abolished (Kavi Kishor et al., 2005). VPS34, class-III phosphatidylinositol 3-kinase (PI3K), which catalyzes synthesis of phosphatidylinositol 3-phosphate (PI3P) from phosphatidylinositol, also controls proline metabolism (Leprince et al., 2015) and this was confirmed by use of the PI3K inhibitor, LY294002, which adversely affects PI 3P levels and reduced proline, amino acids and sugars accumulation in salt-stressed A. thaliana seedlings. Further, proline accumulation was positively correlated with transcript level of P5CS1 and negatively correlated with transcript and protein levels of ProDH1. Induced expression of ProDH1 in a pi3k-hemizygous mutant indicates the role of PI3K for ProDH1 regulation and thus proline catabolism (Leprince et al., 2015).
Inhibitory effects of compounds isolated from Dioscorea batatas Decne peel on particulate matter-induced pulmonary injury in mice
Published in Journal of Toxicology and Environmental Health, Part A, 2019
Wonhwa Lee, So Yeon Jeong, Myeong Ju Gu, Ji Sun Lim, Eui Kyun Park, Moon-Chang Baek, Jong-Sang Kim, Dongyup Hahn, Jong-Sup Bae
Phosphatidylinositol 3-phosphate (PI3K)/Akt signaling plays a key role in the regulation of cellular survival, proliferation, and metabolism in mammals (Bellacosa et al. 1998; Singleton et al. 2009). Data demonstrated that phenanthrene compounds 1 and 2 significantly induced Akt phosphorylation in MLMVECs, which was attenuated by the PI3 kinase inhibitor LY294002 (Figure 4a). Akt phosphorylation was maintained even in the presence of PM2.5 (1 mg/ml, 6 hr). The protective action of phenanthrene compounds 1 and 2 against PM2.5-induced EC barrier disruption was significantly reduced after addition of LY294002 to MLMVECs (Figure 3b). The major Akt isotype in the endothelium, namely Akt1, was subsequently downregulated to indicate the specific role of phenanthrene compound 1 or 2-induced Akt activation (Shiojima and Walsh 2002). Akt1 small-interfering RNA (siRNA) significantly weakened the protective effects mediated by phenanthrene compounds 1 and 2 against PM challenge (Figure 4b). Therefore, evidence indicates that phenanthrene compounds 1 and 2- induced Akt phosphorylation may be involved in attenuation of PM2.5-induced MLMVEC barrier disruption.
Inhibitory effects of Kyung-Ok-Ko, traditional herbal prescription, on particulate matter-induced vascular barrier disruptive responses
Published in International Journal of Environmental Health Research, 2019
Phosphatidylinositol 3-phosphate (PI3K)/Akt signaling is one of the most critical pathways in the regulation of cellular survival, proliferation, and metabolism in mammals (Bellacosa et al., 1998; Singleton et al. 2009). Therefore, we determined whether KOK could activate Akt, and if KOK-induced Akt activation was maintained even under PM challenge. Data showed that KOK significantly induced Akt phosphorylation, which was attenuated by the PI3 kinase inhibitor, LY294002 in MLMVECs (Figure 3(a)). Akt phosphorylation persisted despite PM treatment (1 mg/mL, 6 h). The addition of LY294002 to MLMVECs significantly abolished the protective ability of KOK against PM2.5-induced EC barrier disruption (Figure 3(c)). To define the specific role of KOK-induced Akt activation, we next knocked down Akt1, the major Akt isotype in the endothelium (Shiojima and Walsh 2002). Akt1 small interfering RNA (siRNA) reduced Akt protein expression (Figure 3(b)) and significantly prevented KOK-mediated protective effects against PM challenge (Figure 3(c)). Taken together, these results indicated that KOK induced Akt phosphorylation, which contributed to the attenuation of PM-induced MLMVECs barrier disruption.
Inhibitory effects of protopanaxatriol type ginsenoside fraction (Rgx365) on particulate matter-induced pulmonary injury
Published in Journal of Toxicology and Environmental Health, Part A, 2019
Wonhwa Lee, Sae-Kwang Ku, Ji-Eun Kim, Soo-Hyun Cho, Gyu-Yong Song, Jong-Sup Bae
Phosphatidylinositol 3-phosphate (PI3K)/Akt signaling is one of the most critical pathways in the regulation of cellular survival, proliferation, and metabolism in mammals (Bellacosa et al. 1998; Singleton et al. 2009). Therefore, experiments were undertaken to determine whether Rgx365 might activate Akt, and if Rgx365-induced Akt activation was maintained even under PM challenge. Data showed that Rgx365 significantly induced Akt phosphorylation in purified MLMVEC, which was attenuated by the PI3 kinase inhibitor, LY294002 in MLMVEC (Figure 5(a)). Akt phosphorylation persisted even in the presence of PM (1 mg/ml, 6 h). The addition of LY294002 to MLMVEC significantly decreased the protective ability of Rgx365 against PM2.5-induced endothelial cell barrier disruption (Figure 5(c)). To assess the specific role of Rgx365-induced Akt activation, Akt1 the major Akt isotype in the endothelium (Shiojima and Walsh 2002) was knocked down, Akt1 small interfering RNA (siRNA) reduced Akt protein expression in purified MLMVECs (Figure 5(b)) and significantly prevented Rgx365-mediated protective effects against PM challenge in purified MLMVECs (Figure 5(c)). Taken together, these results indicated that Rgx365 induced Akt phosphorylation and contributed to attenuation of PM-induced MLMVEC barrier disruption.