Systemic AA amyloidosis in the red fox (Vulpes vulpes)

Area of Science:

• Veterinary Pathology
• Comparative Biochemistry
• Mammalian Genetics

Background:

• AA amyloidosis prevalence varies across mammalian species.
• Fox species exhibit differential susceptibility to AA amyloidosis.
• Red foxes (Vulpes vulpes) are a novel species identified with AA amyloidosis.

Purpose of the Study:

• To identify and characterize AA amyloidosis in Red foxes.
• To determine the amino acid sequence of Red fox serum amyloid A (SAA).
• To compare Red fox SAA with that of other fox species and assess amyloidogenicity.

Main Methods:

• Protein sequencing using Edman degradation.
• Tandem mass spectrometry (MS) analysis of amyloid protein.
• Interspecies sequence comparison and amyloid seeding assays in a mouse model.

Main Results:

• AA amyloidosis was confirmed in Red foxes.
• Red fox SAA consists of 111 amino acid residues.
• Four residue exchanges were noted between Red and Blue fox SAAs, with Lys63 unique to Red fox SAA.
• Red fox amyloid fibrils failed to seed AA amyloidosis in mice.

Conclusions:

• The study identified AA amyloidosis in Red foxes and characterized their SAA protein.
• Sequence differences between Red and Blue fox SAA do not clearly explain differential amyloidogenicity.
• Red fox amyloid fibrils exhibit reduced seeding potential compared to other mammalian species.