| First Author | Zhang K | Year | 2014 |
| Journal | J Neurochem | Volume | 129 |
| Issue | 1 | Pages | 48-59 |
| PubMed ID | 24266713 | Mgi Jnum | J:208186 |
| Mgi Id | MGI:5562462 | Doi | 10.1111/jnc.12527 |
| Citation | Zhang K, et al. (2014) Chromogranin B: intra- and extra-cellular mechanisms to regulate catecholamine storage and release, in catecholaminergic cells and organisms. J Neurochem 129(1):48-59 |
| abstractText | Chromogranin B (CHGB) is the major matrix protein in human catecholamine storage vesicles. CHGB genetic variation alters catecholamine secretion and blood pressure. Here, effective Chgb protein under-expression was achieved by siRNA in PC12 cells, resulting in ~ 48% fewer secretory granules on electron microscopy, diminished capacity for catecholamine uptake (by ~ 79%), and a ~ 73% decline in stores available for nicotinic cholinergic-stimulated secretion. In vivo, loss of Chgb in knockout mice resulted in a ~ 35% decline in chromaffin granule abundance and ~ 44% decline in granule diameter, accompanied by unregulated catecholamine release into plasma. Over-expression of CHGB was achieved by transduction of a CHGB-expressing lentivirus, resulting in ~ 127% elevation in CHGB protein, with ~ 122% greater abundance of secretory granules, but only ~ 14% increased uptake of catecholamines, and no effect on nicotinic-triggered secretion. Human CHGB protein and its proteolytic fragments inhibited nicotinic-stimulated catecholamine release by ~ 72%. One conserved-region CHGB peptide inhibited nicotinic-triggered secretion by up to ~ 41%, with partial blockade of cationic signal transduction. We conclude that bi-directional quantitative derangements in CHGB abundance result in profound changes in vesicular storage and release of catecholamines. When processed and released extra-cellularly, CHGB proteolytic fragments exert a feedback effect to inhibit catecholamine secretion, especially during nicotinic cholinergic stimulation. |
