B cell granule peptides affect human islet amyloid polypeptide (IAPP) fibril formation in vitro.
Islet amyloid polypeptide (IAPP) forms fibrils spontaneously. We examined whether other B cell granule peptides affect formation of beta-pleated sheet fibrils in vitro from human IAPP. Quantitative radioassay (radioactivity of soluble IAPP after adding 125I-IAPP) and thioflavine fluorescence spectroscopy showed that insulin, C-peptide, and pancreastatin inhibited fibril formation by 60-100% at ratio 100:1 (peptide:IAPP), whereas at 1:10 or 1:100, i.e., IAPP in excess, a potentiated IAPP fibril formation was induced by the peptides. Semi-quantitative analysis by electron microscopy yielded similar effects. Thus, spontaneous IAPP fibrillisation is influenced by other B cell secretory granule peptides in a molar ratio dependent manner.
Janciauskiene
S
S
Department of Medicine, Lund University, Malmö, Sweden.
Eriksson
S
S
Carlemalm
E
E
Ahrén
B
B
D000682:Amyloid / Q000378:metabolism* / Q000648:ultrastructure*; D002096:C-Peptide / Q000494:pharmacology*; D053379:Chromogranin A; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D058228:Islet Amyloid Polypeptide; D007515:Islets of Langerhans / Q000378:metabolism*; D008854:Microscopy, Electron; D010187:Pancreatic Hormones / Q000494:pharmacology*; D011108:Polymers / Q000378:metabolism; D013050:Spectrometry, Fluorescence
D000682:Amyloid; D002096:C-Peptide; D053379:Chromogranin A; D007328:Insulin; D058228:Islet Amyloid Polypeptide; D010187:Pancreatic Hormones; D011108:Polymers; C050836:pancreastatin