Details

Autor(en) / Beteiligte

• Montero, Manuel L.
• Liu, Jo‐Wen
• Orozco, José
• Casiano, Carlos A.
• De Leon, Marino

Titel

Docosahexaenoic acid protection against palmitic acid‐induced lipotoxicity in NGF‐differentiated PC12 cells involves enhancement of autophagy and inhibition of apoptosis and necroptosis

Ist Teil von

• Journal of neurochemistry, 2020-12, Vol.155 (5), p.559-576

Ort / Verlag

England: Blackwell Publishing Ltd

Erscheinungsjahr

2020

Quelle

Wiley-Blackwell Journals

Beschreibungen/Notizen

• Lipotoxicity (LTx) leads to cellular dysfunction and cell death and has been proposed to be an underlying process during traumatic and hypoxic injuries and neurodegenerative conditions in the nervous system. This study examines cellular mechanisms responsible for docosahexaenoic acid (DHA 22:6 n‐3) protection in nerve growth factor‐differentiated pheochromocytoma (NGFDPC12) cells from palmitic acid (PAM)‐mediated lipotoxicity (PAM‐LTx). NGFDPC12 cells exposed to PAM show a significant lipotoxicity demonstrated by a robust loss of cell viability, apoptosis, and increased HIF‐1α and BCL2/adenovirus E1B 19 kDa protein‐interacting protein 3 gene expression. Treatment of NGFDPC12 cells undergoing PAM‐LTx with the pan‐caspase inhibitor ZVAD did not protect, but shifted the process from apoptosis to necroptosis. This shift in cell death mechanism was evident by the appearance of the signature necroptotic Topo I protein cleavage fragments, phosphorylation of mixed lineage kinase domain‐like, and inhibition with necrostatin‐1. Cultures exposed to PAM and co‐treated with necrostatin‐1 (necroptosis inhibitor) and rapamycin (autophagy promoter), showed a significant protection against PAM‐LTx compared to necrostatin‐1 alone. In addition, co‐treatment with DHA, as well as 20:5 n‐3, 20:4 n‐6, and 22:5 n‐3, in the presence of PAM protected NGFDPC12 cells against LTx. DHA‐induced neuroprotection includes restoring normal levels of HIF‐1α and BCL2/adenovirus E1B 19 kDa protein‐interacting protein 3 transcripts and caspase 8 and caspase 3 activity, phosphorylation of beclin‐1, de‐phosphorylation of mixed lineage kinase domain‐like, increase in LC3‐II, and up‐regulation of Atg7 and Atg12 genes, suggesting activation of autophagy and inhibition of necroptosis. Furthermore, DHA‐induced protection was suppressed by the lysosomotropic agent chloroquine, an inhibitor of autophagy. We conclude that DHA elicits neuroprotection by regulating multiple cell death pathways including enhancement of autophagy and inhibiting apoptosis and necroptosis. Docosahexaenoic acid (DHA) protects nerve cells from stressful traumatic injuries. Here, we elucidate potential cell death survival mechanisms involved in this protection. Palmitic acid (PAM) overload induces lipotoxicity, apoptosis, and increase in hypoxia inducible factor‐1 alpha (HIF‐1), BCL2/adenivirus E1B 19 kD protein‐interacting protein 3 (BNIP‐3) transcripts in differentiated pheochromocytoma cell line 12 (PC‐12). This PAM‐apoptotic effect is inhibited by DHA. Treatment with PAM and carbobenzoxy‐valyl‐alanyl‐aspartyl‐[O‐methyl] fluoromethylketone (ZVAD) induces a necroptosis response also blocked by DHA through an autophagy survival response. These findings suggest a novel neuroprotective and potentially therapeutic role of DHA capable of inhibiting multiple cell death pathways.