Phosphorylation Enhances Recombinant Heat Shock Protein 27 Performs as Pharmacological Preconditioning to Protect against Lung Ischemia Reperfusion Injury

Abstract

We previously reported that the evidence for a protective role of the innate immune system in lung ischemic preconditioning (IPC), which is mediated a MyD88-independent pathway through TRIF, leading to NF-κB activation also heat shock proteins (HSPs) and protection against lung ischemia-reperfusion (I/R) injury (LIRI). We therefore hypothesized that exogenous HSPs would provide pharmacological preconditioning (PPC). In the present study, we examined whether phosphorylated recombinant HSP27 (prHSP27), which recombinant HSP27 phosphorylated by MAPKAP kinase 2 in vitro, affected PPC to protect against LIRI. C57BL/6 mice received prHSP27(2.5 g/kg) or vehicle 30 minutes prior to 60 minutes of ischemia of their left lungs, followed by 180 minutes of reperfusion or IPC with six cycles of 5 minutes ischemia and 5 minutes reperfusion prior to I/R. Response to injury was quantified by tissue MPO activity, vascular permeability, and leukocyte and inflammatory mediator accumulation in BAL expression. Pretreatment of mice with prHSP27 resulted in the development of a significant smaller LIRI, which quantified by vascular permeability (P=.005), MPO activity (P=.001), and BAL components when compared with vehicle treated lungs. In the prHSP27 treated group, there was no activation of MyD88, TRIF, or NF-κB before I/R as in the IPC group, however a strong activation of HSP-27 was showing before I/R as in the IPC group. In this study, we demonstrated that prHSP27 migrates into lung tissue and maintains its activation. It suggests that prHSP27 may be a useful therapeutic agent to protect against LIRI as PPC.