Annexin A1 Promotes Reparative Angiogenesis and Ameliorates Neuronal Injury in Ischemic Retinopathy

Abstract

Purpose

Retinal ischemia is the main reason for vision threatening. Inflammation and aberrant angiogenesis play an important role in the pathogenesis of ischemia. Annexin A1 (ANXA1) is an endogenous protein modulating anti-inflammatory processes, and its therapeutic potential has been reported in a range of inflammatory diseases. However, the effect of ANXA1 on ischemic retinal injury has not been examined.

Methods

Expression of ANXA1 was assessed by real-time PCR and western blotting, and location of ANXA1 was evaluated by immunofluorescence staining in retina of OIR. The activation of ANXA1 was assayed in HRECs after hypoxia stimuli. The effect of ANXA1 on vascularization of OIR mouse through quantification vaso-obliteration (VO) and neovascularization (NV), as well as expression of relevant angiogenic factors and inflammatory cytokines was compared between wild type and ANXA1 deficiency mice. We also investigated the effect of ANXA1 on retinal neuronal degeneration as measured by electroretinography (ERG) and OCT.

Results

In retinas of OIR, the expression of ANXA1 significantly increased and located in inner retinal layers. ANXA1 was induced in HRECs after hypoxic stimuli. Furthermore, ANXA1 deficiency increased pro-angiogenic and pro-inflammatory cytokines. Ablation of ANXA1 suppressed aortic outgrowth and retinal reparative revascularization and promoted pathological NV to exacerbate retinal dysfunction after ischemia injury.

Conclusions

ANXA1 inhibits angiogenic and inhibits pro-inflammatory cytokines and promotes reparative angiogenesis, thus exhibits neuronal protective function in ischemic retinopathy.

Keywords:

• Annexin A1
• ischemia
• angiogenesis
• inflammation
• retina retinopathy

Acknowledgments

All authors named in the title page approved the final version, and have provided permission to be named and met authorship criteria.

Author contribution

CP and LQ conceived the study and reviewed the manuscript. YH finished experiments, processed the results, and wrote the manuscript. WZ participated experiments and helped analyze the data. CP revised the final version of the manuscript. All authors read and approved the final manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article.

Additional information

Funding

This work was supported by the National Nature Science Foundation of China [Grant number: 81470614].