cPKCγ Inhibits Caspase-9-Initiated Neuronal Apoptosis in an Ischemia Reperfusion Model In Vitro Through p38 MAPK-p90RSK-Bad Pathway

Neurochem Res. 2023 Feb;48(2):362-374. doi: 10.1007/s11064-022-03747-1. Epub 2022 Sep 24.

Abstract

Strokes are one of the leading causes of death and disability in the world. Previously we have found that conventional protein kinase Cγ (cPKCγ) plays neuroprotective role in ischemic strokes. Further, we found that cPKCγ knockdown increased the level of cleaved (cl)-Caspase-3. However, the precise mechanisms underlying cPKCγ-mediated neuronal death remain unclear. To this end, a model incorporating 1 h oxygen-glucose deprivation/24 h reoxygenation (1 h OGD/24 h R) was established in cortical neurons. We found that cPKCγ knockdown remarkably increased neuronal death after OGD. We also found that cPKCγ knockdown increased the level of cl-Caspase-3 through the upstream initiators Capsases-9 (not Caspase-8/12) in OGD-treated neurons. Overexpression of cPKCγ could decrease neuronal death and cl-Caspase-3 and -9 levels. Moreover, cPKCγ knockdown further reduced the phosphorylation levels of p38 MAPK, p90RSK, and Bad. In addition, the protein levels of Bcl-2 and Bcl-xl were decreased after cPKCγ knockdown, whereas that of Bax was increased. In conclusion, our results suggest that cPKCγ partly alleviates ischemic injury through activating the p38 MAPK-p90RSK-Bad pathway and inhibiting Caspase-9 initiated apoptosis. This may have potential as a therapeutic target for ischemic stroke.

Keywords: Apoptosis; Ischemic stroke; OGD/R; cPKCγ; p38 MAPK-p90RSK-Bad pathway.

MeSH terms

  • Animals
  • Apoptosis
  • Caspase 3 / metabolism
  • Caspase 9 / metabolism
  • Glucose / metabolism
  • Ischemia / metabolism
  • Mice
  • Neurons / metabolism
  • Oxygen / metabolism
  • Reperfusion
  • Reperfusion Injury* / metabolism
  • Ribosomal Protein S6 Kinases, 90-kDa / metabolism
  • Ribosomal Protein S6 Kinases, 90-kDa / therapeutic use
  • Signal Transduction*
  • p38 Mitogen-Activated Protein Kinases / metabolism

Substances

  • Caspase 3
  • Caspase 9
  • Glucose
  • Oxygen
  • p38 Mitogen-Activated Protein Kinases
  • Ribosomal Protein S6 Kinases, 90-kDa