Sensory nerve degeneration in a mouse model mimicking early manifestations of familial amyloid polyneuropathy due to transthyretin Ala97Ser
Journal
Neuropathology and Applied Neurobiology
Journal Volume
44
Journal Issue
7
Pages
673_686
Date Issued
2018
Author(s)
Abstract
Aims: Sensory nerve degeneration and consequent abnormal sensations are the earliest and most prevalent manifestations of familial amyloid polyneuropathy (FAP) due to amyloidogenic transthyretin (TTR). FAP is a relentlessly progressive degenerative disease of the peripheral nervous system. However, there is a lack of mouse models to replicate the early neuropathic manifestations of FAP. Methods: We established human TTR knock-in mice by replacing one allele of the mouse Ttr locus with human wild-type TTR (hTTRwt) or human TTR with the A97S mutation (hTTRA97S). Given the late onset of neuropathic manifestations in A97S-FAP, we investigated nerve pathology, physiology, and behavioural tests in these mice at two age points: the adult group (8 – 56?weeks) and the ageing group (>?104?weeks). Results: In the adult group, nerve profiles, neurophysiology and behaviour were similar between hTTRwt and hTTRA97S mice. By contrast, ageing hTTRA97S mice showed small fibre neuropathy with decreased intraepidermal nerve fibre density and behavioural signs of mechanical allodynia. Furthermore, significant reductions in sural nerve myelinated nerve fibre density and sensory nerve action potential amplitudes in these mice indicated degeneration of large sensory fibres. The unaffected motor nerve physiology replicated the early symptoms of FAP patients, that is, sensory nerves were more vulnerable to mutant TTR than motor nerves. Conclusions: These results demonstrate that the hTTRA97S mouse model develops sensory nerve pathology and corresponding physiology mimicking A97S-FAP and provides a platform to develop new therapies for the early stage of A97S-FAP. ? 2018 British Neuropathological Society
SDGs
Other Subjects
alanine; messenger RNA; serine; transthyretin; transthyretin; action potential amplitude; allodynia; animal behavior; animal experiment; animal model; animal tissue; Article; controlled study; denervation; familial amyloid polyneuropathy; female; gastrocnemius muscle; hind paw; homologous recombination; innervation; kidney distal tubule; LoxP site; mechanical stimulation; motor nerve; mouse; mouse model; myelin sheath; myelinated nerve; nerve conduction; nerve degeneration; nerve plexus; neuromuscular junction; neurophysiology; nonhuman; nonmyelinated nerve; point mutation; priority journal; protein expression; sciatic nerve; sensory nerve; skin nerve; sural nerve; animal; disease model; familial amyloid polyneuropathy; genetics; nerve degeneration; pathology; sensory nerve cell; transgenic mouse; Amyloid Neuropathies, Familial; Animals; Disease Models, Animal; Mice; Mice, Transgenic; Nerve Degeneration; Prealbumin; Sensory Receptor Cells
Type
journal article