Biomarkers for the detection of necroptosis

Abstract

Necroptosis has been extensively studied recently, and the receptor-interacting kinase 3 (RIP3 or RIPK3) and its substrate, the pseudokinase mixed lineage kinase domain-like protein, have been discovered to be core components of this process. Classical necroptosis requires RIP1 (or RIPK1) for the activation of RIP3 through the induction of RIP1/RIP3 necrosomes. Increasing evidence from genetic and pharmacological studies has been expanding the view that necroptosis plays important roles in the etiology and/or progression of many human diseases, such as pancreatitis, ischemic injury, and neurodegenerative diseases, among others. Ongoing progress in translational research about necroptosis has highlighted the increasingly important need for the identification of biomarkers for use in disease diagnosis, monitoring, and drug development. This review presents a discussion of the current status of biomarkers that can be used to detect necroptosis both in vitro and in vivo.

Keywords: Biomarker; MLKL; Necroptosis; RIP1; RIP3; Regulated necrosis.

Fig. 1

Signaling pathway of necroptosis. In TNF-triggered necroptosis of human cells, RIP1 is deubiquitinated by CYLD and disassociated from TNF receptor 1 (TNFR1). RIP1 subsequently binds to RIP3 to form a protein complex, termed a necrosome, leading to the activation of both protein kinases. This process results in autophosphorylation of RIP1 at the S14/15 and S166 sites, and autophosphorylation of RIP3 at S227. Activated RIP3 recruits MLKL to the necrosome and phosphorylates MLKL at the T357 and S358 sites. Phosphorylated MLKL oligomerizes and translocates to the plasma membrane. 7N-1 and GSK’963 inhibit RIP1 kinase activity and necroptosis. GSK’872 and GSK’843 block RIP3 kinase activity and RIP3-dependent necrosis. NSA blocks MLKL-dependent necrosis by preventing the membrane translocation of MLKL; NSA has no effect on MLKL phosphorylation or oligomerization