First Author | Yamada T | Year | 1996 |
Journal | J Immunol | Volume | 157 |
Issue | 2 | Pages | 901-7 |
PubMed ID | 8752944 | Mgi Jnum | J:34038 |
Mgi Id | MGI:81516 | Doi | 10.4049/jimmunol.157.2.901 |
Citation | Yamada T, et al. (1996) Accelerated amyloid deposition in mice treated with the aspartic protease inhibitor, pepstatin. J Immunol 157(2):901-7 |
abstractText | The development of amyloidotic diseases is believed to be determined in large part by the structure and metabolism of the amyloid subunit protein. The amino-terminal region of serum amyloid A (SAA), the subunit precursor protein in reactive amyloidosis, appears to confer fibrillogenic potential. Here we present data consistent with the hypothesis that amyloid A fibrillogenesis is favored when proteolysis of the amino-terminal region of SAA is impaired. Murine tissue extracts were found to contain pepstatin-inhibitable protease activity that cleaved mouse SAA2 between Glu8 and Ala9. Tissues obtained from mice that had been treated with pepstatin for 3 days lacked this activity. To investigate a possible relationship between inhibition of aspartic proteases and amyloidogenesis, mice were treated with pepstatin while concurrently undergoing a standard amyloid induction protocol (repeated casein injections). Pepstatin-treated mice showed amyloid deposition significantly sooner than the control group, which had received only casein. During the preamyloidotic phase, pepstatin-treated mice had higher concentrations of SAA in serum and spleen than control mice. In addition, clearance of injected 125I-labeled SAA from plasma was significantly delayed. Based on these findings, it is reasonable to postulate that inhibition of aspartic protease activity can lead to an accumulation of amino-terminally intact SAA molecules and thereby accelerate amyloid fibril formation. |