Identification of Piperlongumine as Potent Inhibitor of Necroptosis

Abstract

Excessive necroptosis contributes to the pathogenesis of several inflammatory and neurodegenerative diseases. Here, using a high-throughput screening approach, we investigated the anti-necroptosis effects of piperlongumine, an alkaloid isolated from the long pepper plant, in vitro and in a mouse model of systemic inflammatory response syndrome (SIRS). Methods: A natural compound library was screened for anti-necroptosis effects in cellular. The underlying mechanism of action of the top candidate piperlongumine was explored by quantifying the necroptosis marker phosphorylated receptor-interacting protein kinase 1 (p-RIPK1) by Western blotting. The anti-inflammatory effect of piperlongumine was assessed in a tumor necrosis factor α (TNFα)-induced SIRS model in mice. Results: Among the compounds investigated, piperlongumine significantly rescued cell viability. The half maximal effective concentration (EC 50 ) of piperlongumine for inhibiting necroptosis was 0.47 μM in HT-29 cells, 6.41 μM in FADD-deficient Jurkat cells, and 2.33 µM in CCRF-CEM cells, while the half maximal inhibitory concentration (IC 50 ) was 95.4 µM in HT-29 cells, 93.02 µM in FADD-deficient Jurkat cells, and 161.1 µM in CCRF-CEM cells. Piperlongumine also significantly inhibited TNFα-induced intracellular RIPK1 Ser166 phosphorylation in cell lines and significantly prevented decreases in body temperature and improved survival in SIRS mice. Conclusion:As a potent necroptosis inhibitor, piperlongumine prevents phosphorylation of RIPK1 at its activation residue Ser166. Piperlongumine thus potently inhibits necroptosis at concentrations safe enough for human cells in vitro and inhibits TNFα-induced SIRS in mice. Piperlongumine has potential clinical translational value for the treatment of the spectrum of diseases associated with necroptosis, including SIRS.

ACSL4-Mediated Ferroptosis and Its Potential Role in Central Nervous System Diseases and Injuries

“…In general, ferroptosis has three essential features: (1) oxidation of PUFAs (including membrane phospholipids); (2) redox activities related to iron utilization; (3) loss of lipid hydrogen peroxide (LOOH) repair capacity [ 8 ]. Morphologically, ferroptosis cells exhibit typical changes in mitochondrial membrane shrinkage, reduction or disappearance of mitochondrial cristae, and rupture of the outer membrane, whereas mitochondria usually show swelling in other forms of cell death [ 39 , 40 , 41 ]. Furthermore, treated with the ferroptosis inducer erastin, the nuclei of cancer cells retained their structural integrity and no nuclear pyknosis or chromatin edge clustering was observed [ 42 ].…”