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Gymnema montanum improves endothelial function via inhibition of endoplasmic reticulum stress by activating Nrf2 signaling
Dornadula Sireesh1, Natarajan Suganya2, Suvro Chatterjee3, Kunka Mohanram Ramkumar1
1 SRM Research Institute; Department of Biotechnology, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur -603 203, Tamil Nadu, India
2 Department of Biotechnology, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur -603 203; Vascular Biology Lab, AU-KBC Research Centre, Anna University, Chromepet, Chennai-600 044, Tamil Nadu, India
3 Vascular Biology Lab, AU-KBC Research Centre, Anna University, Chromepet, Chennai-600 044, Tamil Nadu, India
Correspondence Address:
Kunka Mohanram Ramkumar
SRM Research Institute; Department of Biotechnology, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur -603 203, Tamil Nadu
India
 Source of Support: This study was supported by the Indian Council of Medical Research (grant no.59/57/2011/BMS/TRM), Government of India, Conflict of Interest: None  | 2 |
DOI: 10.4103/2221-1691.287164
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Objective: To investigate the effects of Gymnema montanum leaf extract against endoplasmic reticulum (ER) stress-induced toxicity in endothelial cells.
Methods: The immortalized endothelial hybrid cell, EA.hy926 was treated with different concentrations of Gymnema montanum leaf extract (0-100 μg/mL) and the ER stress inducer, tunicamycin. The cytotoxicity was assessed by MTT as well as lactate dehydrogenase and malondialdehyde levels were determined. The levels of ER stress markers, GRP78 and CHOP were analysed by Western blot assay. The Gymnema montanum leaf extract-mediated activation of nuclear factor erythroid 2-related factor 2 (Nrf2) was assessed by cell-based luciferase enzyme fragment complementation assay and antioxidant responsive element driven luciferase reporter assay. The levels of phosphoproteins of the MAPK pathway were analyzed using the Bioplex system.
Results: A dose-dependent cytoprotective effect of Gymnema montanum leaf extract was observed in tunicamycin-induced toxicity. Gymnema montanum leaf extract significantly reduced lactate dehydrogenase activity and malondialdehyde levels in ER stress-induced endothelial cells. It also suppressed ER stress markers dose dependently and inhibited the phosphorylation of JNK, ERK, MEK and p38 MAPK in tunicamycin-induced endothelial cells. Moreover, Gymnema montanum leaf extract increased the expression of Nrf2 and its downstream targets in endothelial cells.
Conclusions: Gymnema montanum leaf extract attenuates ER stress by increasing the expression of Nrf2 and its downstream genes. |
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