Role PKA and p38 MAPK on ROS production in neutrophil age-related : lack of IL-10 effect in older subjects.

Abstract

Background: There is a large increase in the number of elderly people in modern societies. This demographic phenomenon has been paralleled by an epidemic of chronic diseases and inflammatory processes usually associated with advanced age. Objective: We studied the role of protein kinase A (PKA), protein kinase B (Akt/PKB) and p38 mitogen-activated protein kinase (p38MAPK) signaling pathways in ROS produced by neutrophils induced by pro-interferon-gamma (IFN-γ) or anti-inflammatory interleukin 10 (IL-10) cytokines age-related. Methods: The ROS generation was studied in healthy subjects in age ranging from 20 to 80 years old divided in five age groups: (20–39), (40–49), (50–59), (60–69) and (70–80) years old. ROSproduction was quantified in a luminol-dependent chemiluminescence assay and the results were expressed as relative light units/min). Results: ROSproduction in human neutrophil was activated by IFN-γ in all the groups studied. This activation was down-regulated by IL-10. The inhibitory effect of IL-10 on 20–49 years old group was reversed by the pre-treatment with H89 (PKA inhibitor) but not with PD169316 (p38MAPK inhibitor). This differential effect of IL-10 associated with age was not observed with the neutrophil pre-treatment with Akt/PKB or NADPH-oxidase inhibitor (DPI). Lack of IL-10effect on ROSproduction was observed in oldersubjects (50–80 years old). The effect of IL-10 showed a significant inhibition of ROSproduction similar to those got with PD169316 alone as compared to that of p38MAPK. Conclusion: The results suggest that inhibitory effect of the ROSproduction mediated by IL-10 depends on PKA for the younger and the lackeffect on the elderly is p38MAPK dependent.