Presence and release of SR-17 (chromogranin B 586–602) in the porcine splenic nerve and its enzymatic degradation by CD26/dipeptidyl peptidase IV

• Published in: Regulatory peptides 2002-06, Vol.106 (1), p.71-79
• Main Authors: Depreitere, Jan, Durinx, Christine, Wang, Zesheng, Coen, Edmond, Lambeir, Anne-Marie, Scharpé, Simon, De Potter, Werner, Nouwen, Etienne J.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Aminoacids, peptides. Hormones. Neuropeptides; Analytical, structural and metabolic biochemistry; Animals; Axonal Transport; Biological and medical sciences; CgB; Chromogranin B; Chromogranins - analysis; Chromogranins - chemistry; Chromogranins - metabolism; Dipeptidyl Peptidase 4 - metabolism; DPP IV; Enzyme-Linked Immunosorbent Assay; Fundamental and applied biological sciences. Psychology; Humans; Immunohistochemistry; In Vitro Techniques; Models, Animal; Molecular Sequence Data; Norepinephrine - metabolism; Peptide Fragments - analysis; Peptide Fragments - chemistry; Peptide Fragments - metabolism; Phentolamine - pharmacology; Processing; Proteins; Secretogranin I; Spleen - chemistry; Spleen - innervation; Swine; Sympathetic nerve
• ISSN: 0167-0115; 1873-1686
• DOI: 10.1016/S0167-0115(02)00038-1

Using the pig splenic nerve as a model, we investigated the proteolytic processing of porcine chromogranin B (CgB) during its axonal transport. An ELISA was developed for SR-17 (CgB 586–602), a novel CgB-derived peptide, originally found in the adrenal medulla. The results demonstrate that CgB is processed in an early stage during its axonal transport. Immunohistochemical data, based on a rabbit anti-SR-17 antiserum, show that the spleen CgB/SR-17 is exclusively present in the nerve endings. No SR-17 immunoreactivity (IR) was found in splenocytes. We also provide evidence that SR-17 is co-released with noradrenaline (NA) upon electrical stimulation of the splenic nerve. Its release is frequency-dependent and strongly enhanced in the presence of the α-blocking agent phentolamine. In addition, we show that the new CgB-peptide can serve as a substrate for the lymphocyte surface glycoprotein CD26, also known as dipeptidyl peptidase IV (DPP IV), generating a new peptide ER-15 (CgB 588–602).