MM2-cortical-type sporadic Creutzfeldt-Jakob disease with early stage cerebral cortical pathology presenting with a rapidly progressive clinical course

New Insights into Folding, Misfolding, and Nonfolding Dynamics of a WW Domain

Intermediate states in protein folding are associated with formation of amyloid fibrils, which are responsible for a number of neurodegenerative diseases. Therefore, prevention of the aggregation of folding intermediates is one of the most important problems to overcome. Recently, we studied the origins and prevention of formation of intermediate states with the example of the Formin binding protein 28 (FBP28) WW domain. We demonstrated that the replacement of Leu26 by Asp26 or Trp26 (in ∼15% of the folding trajectories) can alter the folding scenario from three-state folding, a major folding scenario for the FBP28 WW domain (WT) and its mutants, toward two-state or downhill folding at temperatures below the melting point. Here, for a better understanding of the physics of the formation/elimination of intermediates, (i) the dynamics and energetics of formation of β-strands in folding, misfolding, and nonfolding trajectories of these mutants (L26D and L26W) is investigated; (ii) the experimental structures of WT, L26D, and L26W are analyzed in terms of a kink (heteroclinic standing wave solution) of a generalized discrete nonlinear Schrödinger equation. We show that the formation of each β-strand in folding trajectories is accompanied by the emergence of kinks in internal coordinate space as well as a decrease in local free energy. In particular, the decrease in downhill folding trajectory is ∼7 kcal/mol, while it varies between 31 and 48 kcal/mol for the three-state folding trajectory. The kink analyses of the experimental structures give new insights into formation of intermediates, which may become a useful tool for preventing aggregation.

Clinicopathological findings of an MM2-cortical-type sporadic Creutzfeldt-Jakob disease patient with cortical blindness during a course of glaucoma and age-related macular degeneration

Here, we report an autopsy-verified patient with MM2-coritical-type sporadic Creutzfeldt-Jakob disease (MM2C-type sCJD) presenting cortical blindness during a course of glaucoma and age-related macular degeneration, and focus on the difficulties involved in early clinical diagnosis. An 83-year-old man was admitted to our hospital 15 months after the onset of cortical blindness, and 9 months after the onset of progressive dementia. Neurological examination revealed dementia, frontal signs, visual disturbance, dysphagia, myoclonus and exaggerated tendon reflexes in the four extremities. Diffusion-weighted MRI (DW-MRI) showed cortical hyperintensities predominantly in the bilateral occipital lobes. PRNP gene analysis showed no mutations with methionine homozygosity at codon 129. Cerebrospinal fluid (CSF) examination revealed elevation of 14–3-3 and total tau protein. The symptoms progressed gradually, and the patient died of aspiration pneumonia, 30 months after the onset. Neuropathological examination revealed extensive large confluent vacuole-type spongiform changes in the cerebral cortices. Prion protein (PrP) immunostaining showed perivascular and plaque-type PrP deposits. We diagnosed our patient as MM2C-type sCJD. There are two difficulties in the early clinical diagnosis of MM2C-type sCJD with ocular disease in the elderly; delayed utilization of DW-MRI, and accompaniment of ocular disease. For early diagnosis of MM2C-type sCJD, we conclude that clinician should perform DW-MRI for patients with isolated dementia or cortical visual disturbance.