Identification of a novel secretogranin II-derived peptide in the adult and fetal human adrenal gland

Abstract

Molecular cloning of secretogranin II (SgII) in different species has revealed the existence of a highly conserved 66-amino acid peptide (EM66) flanked by preserved pairs of basic residues. In the present study we have localized and characterized EM66 in the human adrenal gland. A fusion protein containing the human EM66 peptide was produced in E. coli and used to raise polyclonal antibodies in rabbits. Immunohistochemical staining of human adrenal slices revealed intense labeling of adrenochromaffin cells in the adult and fetal gland. HPLC analysis of adrenal extracts showed the presence of an immunoreactive peak exhibiting the same retention time as recombinant EM66 in both adult and fetus. These data demonstrate that post-translational processing of SgII actually generates a novel peptide in the human adrenal gland. The conservation of the sequence of EM66 in vertebrates and the occurrence of the mature peptide during early ontogenesis of the human adrenal gland strongly suggest that EM66 could exert physiological activities.

A potential role for the secretogranin II‐derived peptide EM66 in the hypothalamic regulation of feeding behaviour

“…EM66 was named according to its length (66 amino acids) and its N-and C-terminal glutamic acid and methionine residues, respectively, in the human sequence. [10][11][12][13][14][15][16] EM66 was initially characterised in the human adrenal gland, in gonadotrophs and lactotrophs of the rat pituitary, and in specific rodent hypothalamic nuclei, suggesting that, upon stimulation, EM66 may be released to act as an autocrine, paracrine and/or endocrine factor. 17,18 Clinically, it has been shown that EM66 is present in tumoural chromaffin cells and represents a sensitive diagnostic and pronostic marker of pheochromocytoma.…”

Differential Expression of Secretogranins II and III in Canine Adrenal Chromaffin Cells and Pheochromocytomas

“…It is speculated that this difference is due to the presence of a functional cAMP response element in the promoter of the SgII gene. 2 Furthermore, SgII has been known to produce functionally active neurotrophic or angiogenic peptides such as secretoneurin, 11,12,[15][16][17]56 EM66, [57][58][59] and manserin 60,61 through the processing of its precursor protein. 62 However, the SgIII precursor protein does not produce active peptides, 3 despite undergoing similar proteolytic processing of the precursor protein.…”

The Natural Antimicrobial Chromogranins/Secretogranins- Derived Peptides – Production, Lytic Activity and Processing by Bacterial Proteases

“…The numerous cleavage sites are consistent with the specificity of prohormone convertases (PC1/3 and PC2) and carboxypeptidase E (CPE), that reside within chromaffin granules (Metz-Boutigue et al, 1993;Seidah & Chretien 1999). Secretogranin II (SgII), the third member of the chromogranin family is also processed to generate several natural fragments (Metz-Boutigue et al, 1993;Anouar et al, 1998;Marksteiner et al, 1993;Yajima et al, 2004). The discovery that pancreastatin, a chromogranin A (CGA)-derived peptide inhibits insulin secretion from pancreatic beta-cells, initiated the concept of prohormone (Eiden, 1987;tatemoto et al, 1986).…”