Capsaicin stimulates glucose uptake in C2C12 muscle cells via the reactive oxygen species (ROS)/AMPK/p38 MAPK pathway

Erythropoietin (EPO) is a cytokine produced primarily in the kidney that is essential for red blood cell production. Apart from playing a role in hematopoiesis, EPO also has a protective role in heart myocytes, ovarian, glial cells brain and retinal diseases. In this study we observed that recombinant human EPO (rhEPO) reduces Hypoxia/ Reperfusion (H/R) injury by virtue of its effect on EPO receptor prosurvival signaling pathway, which ultimately leads to reduced expression of apoptotic proteins and increased survival of cardiomyocytes. H9C2 cells were exposed to H/R with or without pretreatment using 10, 15 and 20 U/ml of rhEPO. We determined viability using MTT, nuclear fragmentation by Hoechst staining, apoptotic nuclei by Acridine orange and Ethidium bromide, Reactive Oxygen Species (ROS) by Dicholorofluoresin Diacetate and activity of late apoptotic protease, Caspase-3 by colorimetric Caspase-3 assay. The expression of mitochondrial superoxide dismutase (MnSOD) by RT-PCR and Western blot, phospho-Akt and p38 MAPK by Confocal microscopy were analyzed. Cell viability is increased in cells pretreated with rhEPO compared to cell exposed to H/R. Cells subjected to H/R showed early apoptotic and late apoptotic cells but showed normal nuclei with intact cell membrane in cells pretreated with rhEPO. Intracellular production of ROS and Caspase-3 activity was decreased in cells pretreated with rhEPO compared to cells exposed to H/R. The expression of MnSOD RNA and protein was up-regulated in response to rhEPO, but not in H/R. The phosphorylative activation of Akt, p38MAPK progressively diminished during H/R but increased in rhEPO pretreated cells. We show that rhEPO prevents apoptosis in cardiomyocytes, subjected to H/R injury via phosphorylation of Akt and p38MAPK. These results it is hoped would help us distinguish the cell signaling pathways involved in cardioprotection and thus would open new avenues in cardiovascular therapy.

Download Full-text

Reactive oxygen species-sensitive p38 MAPK controls thrombin-induced migration of vascular smooth muscle cells

Journal of Molecular and Cellular Cardiology ◽

10.1016/j.yjmcc.2003.09.014 ◽

2004 ◽

Vol 36 (1) ◽

pp. 49-56 ◽

Cited By ~ 51

Author(s):

Z Wang

Keyword(s):

Reactive Oxygen Species ◽

Smooth Muscle ◽

Vascular Smooth Muscle ◽

Smooth Muscle Cells ◽

P38 Mapk ◽

Vascular Smooth Muscle Cells ◽

Reactive Oxygen ◽

Muscle Cells ◽

Oxygen Species

Download Full-text

Visfatin, a novel adipokine, stimulates glucose uptake through the Ca2+-dependent AMPK–p38 MAPK pathway in C2C12 skeletal muscle cells

Journal of Molecular Endocrinology ◽

10.1530/jme-14-0274 ◽

2015 ◽

Vol 54 (3) ◽

pp. 251-262 ◽

Cited By ~ 15

Author(s):

Jung Ok Lee ◽

Nami Kim ◽

Hye Jeong Lee ◽

Yong Woo Lee ◽

Joong Kwan Kim ◽

...

Keyword(s):

Skeletal Muscle ◽

Protein Kinase ◽

Glucose Uptake ◽

P38 Mapk ◽

Mapk Pathway ◽

Muscle Cells ◽

Skeletal Muscle Cells ◽

Ampk Phosphorylation ◽

P38 Mapk Pathway ◽

C2c12 Skeletal Muscle Cells

Visfatin is a novel adipocytokine produced by visceral fat. In the present study, visfatin increased AMP-activated protein kinase (AMPK) phosphorylation in mouse C2C12 skeletal muscle cells. It also increased phosphorylation of the insulin receptor, whose knockdown blocked visfatin-induced AMPK phosphorylation and glucose uptake. Visfatin stimulated glucose uptake in differentiated skeletal muscle cells. However, inhibition of AMPKα2 with an inhibitor or with knockdown of AMPKα2 using siRNA blocked visfatin-induced glucose uptake, which indicates that visfatin stimulates glucose uptake through the AMPKα2 pathway. Visfatin increased the intracellular Ca2+concentration. STO-609, a calmodulin-dependent protein kinase kinase inhibitor, blocked visfatin-induced AMPK phosphorylation and glucose uptake. Visfatin-mediated activation of p38 MAPK was AMPKα2-dependent. Furthermore, both inhibition and knockdown of p38 MAPK blocked visfatin-induced glucose uptake. Visfatin increased glucose transporter type 4 (GLUT4) mRNA and protein levels. In addition, visfatin stimulated the translocation of GLUT4 to the plasma membrane, and this effect was suppressed by AMPKα2 inhibition. The present results indicate that visfatin plays an important role in glucose metabolism via the Ca2+-mediated AMPK–p38 MAPK pathway.

Download Full-text