Protective Effect of l-Theanine on Cadmium-Induced Apoptosis in PC12 Cells by Inhibiting the Mitochondria-Mediated Pathway

Abstract

L-Theanine is an amino acid derivative from green tea. The present work was aimed at the effect of L-theanine on neuron-like rat pheochromocytoma (PC12) cells stimulated with cadmium chloride. Treatment with L-theanine before cadmium exposure increased cell viability; the experiments of Annexin V/PI staining indicated that L-theanine inhibited cadmium-induced cell apoptosis. Meanwhile, L-theanine decreased ROS production and protected from cadmium-induced disruption of mitochondrial transmembrane potential. Compared with cadmium-treated cells, L-theanine could also decrease the ratio of Bax/Bcl-2, as well as the level of cleaved caspase-9, caspase-3 and poly(ADP-ribose) polymerase. Furthermore, L-theanine depresses cadmium-induced up regulation of phosphorylations of PI3K/Akt, MAPK ERK1/2, and JNK signaling. These data suggest that L-theanine pretreatment reduces severity of cadmium toxicity probably via antioxidant action. Therefore, it may be concluded that L-theanine could be exploited for prevention of cadmium-induced diseases.

L-Theanine Protects H9C2 Cells from Hydrogen Peroxide-Induced Apoptosis by Enhancing Antioxidant Capability

“…Fortunately, L-theanine pretreatment effectively attenuated the reduction of pro-Caspase-3 and the increase of cleaved-PARP. This result largely agrees with the previous studies [ 16 , 23 , 31 , 33 ] mentioned above, suggesting that L-theanine pretreatment protects H9C2 cells from H 2 O 2 -induced apoptosis.…”

“…Previous studies have shown that L-theanine pretreatment (1 mM) diminishes ethanol-induced [ 16 ] and H 2 O 2 -induced [ 23 ] apoptosis of hepatocytes by decreasing the expression of cleaved-PARP and Caspase-3. L-theanine pretreatment (0.5 mM) also depresses cadmium-induced upregulation of Caspase-3 and the cleavage of PARP in pheochromocytoma (PC12) cells [ 33 ]. Our data show that H 2 O 2 induced pro-Caspase-3 downregulation and PARP cleavage in H9C2 cells, denoting that the cells were undergoing apoptosis [ 34 ], and this result is consistent with the apoptosis ratio of flow cytometric analysis.…”

l‐Theanine inhibits proinflammatory PKC/ERK/ICAM‐1/IL‐33 signaling, apoptosis, and autophagy formation in substance P‐induced hyperactive bladder in rats

“…l ‐Theanine has shown a therapeutic effect on nervous system diseases and cardiovascular diseases. l ‐Theanine significantly inhibited apoptosis by recovering mitochondrial function including decreased ROS production, restored mitochondrial membrane potential, and decreased mitochondrial release of cytochrome c. In addition, l ‐theanine could upregulate the expression of anti‐apoptotic protein Bcl‐2 and decrease the level of active Caspase 3 protein through Akt, ERK1/2, and JNK signaling pathways . l ‐Theanine significantly suppressed the elevation in the hepatic expression of Bax and caspase 3 induced by doxorubicin‐induced hepatoxicity, while the increased expression of Fas was not affected by theanine indicating theanine preferentially blocking the Bax‐mediated intrinsic pathway among the apoptotic signals .…”

PARP-1 overexpression contributes to Cadmium-induced death in rat proximal tubular cells via parthanatos and the MAPK signalling pathway

“…Apoptosis can be divided into three pathways: the death receptors-mediated pathway, the endoplasmic reticulum pathway, and the mitochondria-mediated apoptosis pathway. Among them, the mitochondria-mediated apoptosis pathway is the most important pathway 37, 38 . Mitochondria-mediated apoptosis mainly involves the release of cytochrome C and AIF, and the activation of caspase-9/3 and Bax 39 .…”