Pharmacological Treatment with Annexin A1 Reduces Atherosclerotic Plaque Burden in LDLR-/- Mice on Western Type Diet

Abstract

ObjectiveTo investigate therapeutic effects of annexin A1 (anxA1) on atherogenesis in LDLR-/- mice.MethodsHuman recombinant annexin A1 (hr-anxA1) was produced by a prokaryotic expression system, purified and analysed on phosphatidylserine (PS) binding and formyl peptide receptor (FPR) activation. Biodistribution of 99mTechnetium-hr-anxA1 was determined in C57Bl/6J mice. 12 Weeks old LDLR-/- mice were fed a Western Type Diet (WTD) during 6 weeks (Group I) or 12 weeks (Group P). Mice received hr-anxA1 (1 mg/kg) or vehicle by intraperitoneal injection 3 times per week for a period of 6 weeks starting at start of WTD (Group I) or 6 weeks after start of WTD (Group P). Total aortic plaque burden and phenotype were analyzed using immunohistochemistry.ResultsHr-anxA1 bound PS in Ca2+-dependent manner and activated FPR2/ALX. It inhibited rolling and adherence of neutrophils but not monocytes on activated endothelial cells. Half lives of circulating 99mTc-hr-anxA1 were <10 minutes and approximately 6 hours for intravenously (IV) and intraperitoneally (IP) administered hr-anxA1, respectively. Pharmacological treatment with hr-anxA1 had no significant effect on initiation of plaque formation (-33%; P = 0.21)(Group I) but significantly attenuated progression of existing plaques of aortic arch and subclavian artery (plaque size -50%, P = 0.005; necrotic core size -76% P = 0.015, hr-anxA1 vs vehicle) (Group P).ConclusionHr-anxA1 may offer pharmacological means to treat chronic atherogenesis by reducing FPR-2 dependent neutrophil rolling and adhesion to activated endothelial cells and by reducing total plaque inflammation.

Annexin A1 attenuates microvascular complications through restoration of Akt signalling in a murine model of type 1 diabetes

“…*p < 0.05 cardiomyopathy and nephropathy. Previously, both full-length AXNA1 and the Ac2-26 peptide (the N-terminal functional fragment of ANXA1) have been used in vivo and both elicit biological function [17][18][19]). In this study, we chose to use fulllength hrANXA1, as the dose of full-length ANXA1 needed to induce biological function is up to 20 times less than that of the Ac2-26 peptide [36] and 14 times less than that needed to induce changes in gene expression in terms of molarity [37].…”

“…in 0.9 mol/l citrate buffer, 5 days, n = 8), while sham mice received vehicle only (10 ml/kg, 0.9 mol/l citrate buffer i.p., 5 days, n = 8). hrANXA1 was produced and purified as previously published [18]. Treatment groups received either prophylactic treatment (weeks 1-13 after STZ administration, n = 6), treatment during STZ administration (days 1-5, n = 6) or therapeutic treatment (weeks 8-13 after STZ administration, n = 6) with hrANXA1 (1 μg, 100 μl, 50 mmol/l HEPES; 140 mmol/l NaCl; pH 7.4, i.p.)…”

“…ANXA1 levels are modulated in many disease states including cancer [13], multiple sclerosis [14], cystic fibrosis [15] and obesity/the metabolic syndrome [16]. Human recombinant ANXA1 (hrANXA1) or its N-terminal peptide (Ac2-26) have therapeutic benefits in many experimental models of disease, including rheumatoid arthritis [17], atherosclerosis [18] and nonalcoholic steatohepatitis [19].…”

Protective Aptitude of Annexin A1 in Arterial Neointima Formation in Atherosclerosis-Prone Mice—Brief Report

“…5,13 Of note, it has been demonstrated that arterial-specific nanodelivery of Ac2-26 could be a promising tool to prevent atheroprogression, a strategy that may also be applicable to treatment of angioplasty-related side effects. 14 In line with previously successfully used FPR2 ligands, 3 stents coated with AnxA1 protein could potentially be suitable to prevent lumen loss and inflammation after arterial injury.…”

Delivery strategies to control inflammatory response: Modulating M1–M2 polarization in tissue engineering applications

“…Thus, the Ac2-26 peptide derived from Annexin A1 has strong pro-resolution effects in vivo; however, further studies need to be performed to elucidate its role in macrophage polarization. One recent study found that full-length Annexin A1 increased IL-10 secretion and decreased the M1 macrophage phenotype [78] whereas another study found that Annexin A1 did not appear to contribute to macrophage polarization [79]. …”