Temporal Changes in Caspase-1 and Caspase-8 Activities Following Brain Hypoxia With and Without Src kinase Inhibition in a Piglet Animal Model.

Abstract

The Src family kinases are a family of intracellular, non-receptor tyrosine kinases that are involved in a variety of cellular functions including the regulation of inflammation and apoptosis after brain hypoxia. Caspase-1 (C1) activates IL-1β through the formation of complex structures, the inflammasomes, while caspase-8 (C8) is part of the extrinsic apoptotic pathway. C8 has been found to directly activate the production of IL-1β. Previously, we observed that C1 and IL-1β are increased in the acute phase after hypoxia in the brain of piglets, but they follow a different pattern long term, with C1 remaining activated throughout the period of observation, while IL-1β returning to baseline at 15 days. Src kinase inhibition ameliorated the activation of C1 and IL-1β early, but did not appear to have any effect long term. Prompted by these findings, we assessed the changes that occur over time (1 h and 15 days) in C1 and C8 activities after brain hypoxia as well as the effect of pretreatment with a Src kinase inhibitor, PP2 on these biochemical markers. Enzymatic activities were determined by spectrophotometry with measurements of C1 and C8 in each cytosolic brain sample (N = 4 in each group). We found that C1 and C8 activities increase in the acute phase following hypoxia in the brain of newborn piglets, with C8 relatively more than C1 (C8/C1 ratio increased from 2:1 as baseline to 3:1 in hypoxia). Fifteen days after hypoxia C8/C1 ratio decreased to about 1:1. In piglets that were pretreated with a Src kinase selective inhibitor (PP2) and then subjected to hypoxia, the C8/C1 ratio early increase was not observed. Immediately after hypoxia C8 and C1 follow a similar pattern of increase while long term this appears to dissociate. We propose that following this experimental methodology, the previously observed IL-1β production after hypoxia might be associated with C8 rather than C1 and that Src kinase is involved in the above process.

• Authors: Dimitrios Angelis, Tania D Fontánez Nieves, Maria Delivoria-Papadopoulos
• Journal: Neurochemical research (Neurochem Res) Vol. 40 Issue 11 Pg. 2270-9 (Nov 2015) ISSN: 1573-6903 [Electronic] United States
• PMID: 26342830 (Publication Type: Journal Article)

Chemical References

• Interleukin-1beta
• Protein Kinase Inhibitors
• Phosphocreatine
• Adenosine Triphosphate
• src-Family Kinases
• Caspase 8
• Caspase 1

Topics

• Adenosine Triphosphate (metabolism)
• Animals
• Animals, Newborn
• Apoptosis (drug effects)
• Caspase 1 (metabolism)
• Caspase 8 (metabolism)
• Cytosol (drug effects, metabolism)
• Hypoxia, Brain (enzymology)
• Interleukin-1beta (biosynthesis)
• Phosphocreatine (metabolism)
• Protein Kinase Inhibitors (pharmacology)
• Sus scrofa
• src-Family Kinases (antagonists & inhibitors)