Targeting AnxA1/Fpr2/ALX Pathway Regulates Neutrophil Function Promoting Thrombo-Inflammation Resolution in Sickle Cell Disease.

Neutrophils plays a crucial role in the intertwined processes of thrombosis and inflammation. Altered neutrophil phenotype may contribute to inadequate resolution which is known to be a major pathophysiological contributor of thrombo-inflammatory conditions such as Sickle Cell Disease (SCD). The endogenous protein Annexin A1 (AnxA1) facilitates inflammation resolution via Formyl Peptide Receptors (FPRs). We sought to comprehensively elucidate the functional significance of targeting neutrophil dependent AnxA1/FPR2/ALX pathway in SCD. Administration of AnxA1 mimetic peptide AnxA1Ac2-26 ameliorated cerebral thrombotic responses in Sickle transgenic mice via regulation of FPR2/ALX (a fundamental receptor involved in resolution) pathway. We demonstrated direct evidence that neutrophils with SCD phenotype play a key role in contributing to thrombo-inflammation. In addition, AnxA1Ac2-26 regulated activated SCD neutrophils through protein kinase B (Akt) and extracellular signal-regulated kinases (ERK1/2) to enable resolution. Herein, we present compelling conceptual evidence that targeting the AnxA1/FPR2/ALX pathway may provide new therapeutic possibilities against thrombo-inflammatory conditions such as SCD.