Pituitary adenylate cyclase activating polypeptide acts against neovascularization in retinal pigment epithelial cells

Abstract

The purpose of this study was to determine whether pituitary adenylate cyclase activating polypeptide (PACAP) could influence the neovascularization processes in hyperosmotic and oxidative stress in retinal pigment epithelial cells. Hyperosmotic conditions and oxidative stress were induced by 200 mM sucrose and 250 μM hydrogen peroxide (H 2 O 2 ), respectively. Morphology and elasticity of adult retinal pigment epithelial (ARPE-19) cells were measured by atomic force microscopy, while the investigation of junctional molecules, such as occludin and ZO-1, was carried out using immunofluorescence. For cell viability measurement, the MTT test was used. The effect of PACAP on the key angiogenic factors, such as vascular endothelial growth factor, angiogenin, and endothelin-1, was measured by an angiogenesis array and flow cytometry. Hyperosmotic stress-induced reorganization of the cytoskeleton and impairment of the junctions decreased cell viability and upregulated several angiogenic factors. In oxidative stress, we found that opening of the junctions decreased viability and upregulated the expression of angiogenic factors. PACAP was shown to be protective in both conditions. Retinal pigment epithelium cells play an important role in several diseases, such as diabetic retinopathy and macular edema. Therefore, protecting retinal pigment epithelial (RPE) cells with PACAP could be a novel and potential treatment in these diseases.

The Neuropeptide Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) Is Protective in Inflammation and Oxidative Stress-Induced Damage in the Kidney

“…Changes in cell junctional markers, such as zonula occludens-1, were also restored by PACAP treatment as well as the increase in smooth muscle actin, indicative of myofibroblastic transformation. These results are also in accordance with PACAP restoring intercellular junctional properties of epithelial cells, as shown for example in retinal pigment epithelial cells against various stressors [88,89]. Collagen III and IV, as well as laminin and fibronectin extracellular matrix components were increased by cyclosporine A and decreased after PACAP treatment.…”

Protective Effects of PACAP in Peripheral Organs

“…Moreover, PACAP was able to attenuate the levels of some other pro-angiogenic proteins (uPA, angiogenin, and endothelin-1). As a conclusion, PACAP is among the emerging molecules to fight diabetic complications and macular degeneration, similarly to VEGF antagonists, antioxidants, anti-inflammatory agents, and other neuropeptides ( 39 ).…”

Progress in regulatory peptide research

“…The report emphasizes both the involvement of this neuropeptide in the brain circuits underlying anxiety responses and fear processing in mammals, and also the possibility of practical administration of this peptide, even in nonhospital settings, through intranasal administration. Likewise, the description of PACAP actions in neovascularization in the eye by Fabian et al . highlights a peptide action within a very accessible target organ, in which cytoprotection may well provide a comprehensive approach to the treatment of vision‐related degenerative diseases.…”