In situ identification of protein structural changes in prion-infected tissue

Abstract

Transmissible spongiform encephalopathies (TSE) are fatal neurodegenerative disorders characterized by the conversion of the normal prion protein (PrP(C)) into aggregates of its pathological conformer (PrP(Sc)). The mechanism behind this structural conversion is unclear. We report the identification of disease-related protein structural differences directly within the tissue environment. Utilizing a synchrotron infrared (IR) light source, IR images of protein structure were obtained at a subcellular resolution, revealing regions of decreased alpha-helical content and elevated beta-sheet structure in and around infected neurons in the 263 K scrapie hamster model. PrP(Sc) immunostaining of the same tissue demonstrated that the elevated beta-sheet regions correspond to regions where the misfolded structure of PrP(Sc) is located. No evidence of these structural changes was observed in normal neurons.

FTIR Imaging of Brain Tissue Reveals Crystalline Creatine Deposits Are an ex Vivo Marker of Localized Ischemia during Murine Cerebral Malaria: General Implications for Disease Neurochemistry

“…As described by the current authors and other researchers, FTIR spectroscopic functional group images generated from band intensities in the second-derivatives of the spectra reveal chemical contrast characteristic of specific tissue layers. 10,11,42,43 In this study, false color functional group images were generated from the second-derivative intensity of the lipid carbonyl ν(CO) band centered at 1742 cm , and were used to visualize the distribution of the three major tissue layers of the cerebellum (inner white matter, granular layer, and molecular layer). Functional group images generated from the second-derivative intensity of the ν s (COO − ) band centered at 1402 cm −1 , which were attributable to creatine, were used to visualize the location of crystalline creatine microdeposits, as described by other researchers.…”

Multivariate Analysis for Fourier Transform Infrared Spectra of Complex Biological Systems and Processes

“…In this way, FTIR microspectroscopy provides detailed information on several biological processes in situ, among which stem cell differentiation [1][2][3][4][5], somatic cell reprogramming [6], cell maturation [7,8], amyloid aggregation [9][10][11][12] and cancer onset and progression [13][14][15], making it possible to disclose the infrared response not only from single cells, but also from subcellular compartments [8,16,17].…”

Protein Structure and Function in the Time-Domain of Vibrational Spectroscopies. The Promising Applications of IR Synchrotron Radiation Micro-Spectroscopy

“…Recently Kneipp et al [32], using a synchrotron radiation IR source and in situ FTIR micro-spectroscopy, have been able to collect IR images of protein structures at a subcellular resolution. Using an IR microscope, protein structures were imaged in individual neurons from the dorsal ganglia of 263 K scrapie-infected Syrian hamster trying to identify disease-related protein structural differences within tissue sections of individual neurons.…”