1. Variation of amino acid sequences of serum amyloid a (SAA) and immunohistochemical analysis of amyloid a (AA) in Japanese domestic cats
- Author
-
Kazuyuki Uchida, James K. Chambers, Hiroyuki Nakayama, Koichi Ohno, Takashi Tamamoto, Meina Tei, and Kenichi Watanabe
- Subjects
Male ,0301 basic medicine ,040301 veterinary sciences ,Inflammation ,Biology ,Cat Diseases ,0403 veterinary science ,Pathogenesis ,03 medical and health sciences ,Amyloid disease ,Japan ,AA amyloidosis ,Pathology ,medicine ,Animals ,Amino Acid Sequence ,Serum amyloid A ,Peptide sequence ,Serum Amyloid A Protein ,Full Paper ,General Veterinary ,Japanese domestic cat ,fibril formation ,Amyloidosis ,DNA ,04 agricultural and veterinary sciences ,medicine.disease ,Molecular biology ,SAA gene ,030104 developmental biology ,Genes ,Cats ,Female ,medicine.symptom - Abstract
Amyloid A (AA) amyloidosis, a fatal systemic amyloid disease, occurs secondary to chronic inflammatory conditions in humans. Although persistently elevated serum amyloid A (SAA) levels are required for its pathogenesis, not all individuals with chronic inflammation necessarily develop AA amyloidosis. Furthermore, many diseases in cats are associated with the elevated production of SAA, whereas only a small number actually develop AA amyloidosis. We hypothesized that a genetic mutation in the SAA gene may strongly contribute to the pathogenesis of feline AA amyloidosis. In the present study, genomic DNA from four Japanese domestic cats (JDCs) with AA amyloidosis and from five without amyloidosis was analyzed using polymerase chain reaction (PCR) amplification and direct sequencing. We identified the novel variation combination of 45R-51A in the deduced amino acid sequences of four JDCs with amyloidosis and five without. However, there was no relationship between amino acid variations and the distribution of AA amyloid deposits, indicating that differences in SAA sequences do not contribute to the pathogenesis of AA amyloidosis. Immunohistochemical analysis using antisera against the three different parts of the feline SAA protein-i.e., the N-terminal, central, and C-terminal regions-revealed that feline AA contained the C-terminus, unlike human AA. These results indicate that the cleavage and degradation of the C-terminus are not essential for amyloid fibril formation in JDCs.
- Published
- 2018