General and Comparative Endocrinology 153 (2007) 115–123 www.elsevier.com/locate/ygcen 0016-6480/$ - see front matter  2006 Elsevier Inc. All rights reserved. doi:10.1016/j.ygcen.2006.12.006 Protective eVects of pituitary adenylate cyclase activating polypeptide in endothelial cells against oxidative stress-induced apoptosis B. Rácz a , B. Gasz a , B. Borsiczky a , F. Gallyas Jr. b , A. Tamás c , R. Józsa c , A. Lubics c , P. Kiss c , E. Röth a , A. Ferencz a , G. Tóth d , O. Hegyi d , I. Wittmann e , I. Lengvári c , A. Somogyvári-Vigh f , D. Reglödi c,¤ a Department of Surgical Research and Techniques, University of Pécs, Pécs, Hungary b Department of Biochemistry and Medical Chemistry, University of Pécs, Pécs, Hungary c Department of Anatomy, Medical Faculty, University of Pécs, Szigeti u 12, 7624 Pécs, Hungary d Department of Medical Chemistry, University of Szeged, Szeged, Hungary e 2nd Department of Medicine and Nephrological Center, University of Pécs, Pécs, Hungary f Tulane University Health Sciences Center School of Medicine, Department of Medicine, New Orleans, USA Received 15 September 2006; revised 15 November 2006; accepted 18 December 2006 Available online 27 December 2006 Abstract Pituitary adenylate cyclase activating polypeptide (PACAP) is a widely distributed neuropeptide that has various diVerent functions in the nervous system and in non-neural tissues. Little is known about the eVects of PACAP in endothelial cells. The aim of the present study was to investigate the eVects of PACAP on endothelial cell survival and apoptotic signaling pathways under oxidative stress. Mouse hemangioendothelioma (EOMA) cells were exposed to 0.5 mM H 2 O 2 which resulted in a marked reduction of cell viability and a parallel increase of apoptotic cells assessed by MTT test and Xow cytometry. Co-incubation with 20 nM PACAP1-38 increased cell viability and reduced the percentage of apoptotic cells. Flow cytometry analysis showed that oxidative stress reduced the phosphorylation of the anti- apoptotic ERK and increased the phosphorylation of the pro-apoptotic JNK and p38 MAP kinases. PACAP1-38 treatment ameliorated these changes: levels of phospho-ERK were elevated and those of phospho-JNK and p38 were decreased. All these eVects were abolished by simultaneous treatment with the PACAP antagonist PACAP6-38. In summary, our results show that PACAP eVectively protects endothelial cells against the apoptosis-inducing eVects of oxidative stress.  2006 Elsevier Inc. All rights reserved. Keywords: Hydrogen peroxide; JNK1/2; ERK1/2; p38 MAPK; Neuropeptide 1. Introduction The survival, growth, and function of endothelial cells are key factors in vascular homeostasis (Irani, 2000). Oxi- dative stress is a major cause of several pathological phe- nomena, including apoptosis in endothelial cells (Irani, 2000; Cuda et al., 2002; Lee et al., 2004). Stress-induced changes of endothelial cells have been implicated in cardiovascular dysfunctions and several other pathological conditions (Irani, 2000; Murakami et al., 2005; Szanto et al., 2006). Oxidative stress leads to activation of numer- ous signal transduction pathways, including members of the mitogen-activated protein kinase (MAPK) family. MAP kinases regulate cell growth, diVerentiation, and apoptosis. Three subfamilies have been identiWed in mam- malian cells: extracellular signal-regulated kinase-p44/42 MAPK (ERK1/2), p38 MAP kinase (p38), and c-Jun N-ter- minal kinase (JNK). Some MAPK-activating stimuli are pro-apoptotic while others are anti-apoptotic, and the divergent biological outcome of MAPK activation is * Corresponding author. Fax: +36 72 536393. E-mail address: dora.reglodi@aok.pte.hu (D. Reglödi).