C-terminal sequence of amyloid-resistant type F apolipoprotein A-II inhibits amyloid fibril formation of apolipoprotein A-II in mice.

Abstract

In murine senile amyloidosis, misfolded serum apolipoprotein (apo) A-II deposits as amyloid fibrils (AApoAII) in a process associated with aging. Mouse strains carrying type C apoA-II (APOA2C) protein exhibit a high incidence of severe systemic amyloidosis. Previously, we showed that N- and C-terminal sequences of apoA-II protein are critical for polymerization into amyloid fibrils in vitro. Here, we demonstrate that congenic mouse strains carrying type F apoA-II (APOA2F) protein, which contains four amino acid substitutions in the amyloidogenic regions of APOA2C, were absolutely resistant to amyloidosis, even after induction of amyloidosis by injection of AApoAII. In vitro fibril formation tests showed that N- and C-terminal APOA2F peptides did not polymerize into amyloid fibrils. Moreover, a C-terminal APOA2F peptide was a strong inhibitor of nucleation and extension of amyloid fibrils during polymerization. Importantly, after the induction of amyloidosis, we succeeded in suppressing amyloid deposition in senile amyloidosis-susceptible mice by treatment with the C-terminal APOA2F peptide. We suggest that the C-terminal APOA2F peptide might inhibit further extension of amyloid fibrils by blocking the active ends of nuclei (seeds). We present a previously unidentified model system for investigating inhibitory mechanisms against amyloidosis in vivo and in vitro and believe that this system will be useful for the development of novel therapies.

• Authors: Jinko Sawashita, Beiru Zhang, Kazuhiro Hasegawa, Masayuki Mori, Hironobu Naiki, Fuyuki Kametani, Keiichi Higuchi
• Journal: Proceedings of the National Academy of Sciences of the United States of America (Proc Natl Acad Sci U S A) Vol. 112 Issue 8 Pg. E836-45 (Feb 24 2015) ISSN: 1091-6490 [Electronic] United States
• PMID: 25675489 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Amyloid
• Apolipoprotein A-II
• Lipoproteins, HDL
• Mutant Proteins
• Peptides
• Cholesterol

Topics

• Amino Acid Sequence
• Amino Acid Substitution
• Amyloid (metabolism, ultrastructure)
• Amyloidosis (blood, pathology)
• Animals
• Apolipoprotein A-II (chemistry, metabolism)
• Cholesterol (blood)
• Lipoproteins, HDL (blood)
• Mice, Inbred C57BL
• Models, Biological
• Molecular Sequence Data
• Mutant Proteins (metabolism)
• Peptides (chemistry, metabolism)
• Polymerization
• Structure-Activity Relationship