Time-course studies of 14-3-3 protein isoforms in cerebrospinal fluid and brain of primates after oral or intracerebral infection with bovine spongiform encephalopathy agent

Abstract

Experimental transmission of bovine spongiform encephalopathy (BSE) to cynomolgus monkeys (Macaca fascicularis) is an animal model for variant Creutzfeldt–Jakob disease (vCJD). The presence of 14-3-3 proteins in cerebrospinal fluid (CSF) samples indicates neuronal destruction and is therefore used as a clinical biomarker. However, time-course studies using 14-3-3 proteins have not been performed until now in simian vCJD. The main goals of this study were to determine isoform patterns, to examine kinetics and to correlate the clinical course with the occurrence of this biomarker in simian vCJD. In monkeys dosed intracerebrally with BSE, the earliest clinical sign of illness was a drop in body weight that was detected months before the onset of mild neurological signs. Macaques dosed orally or intracerebrally with BSE developed neurological signs 4.3 (3.7–4.6) and 4.8 (2.9–6.0) years post-infection, respectively. 14-3-3β- and -γ-positive CSF samples were found around the time of onset of mild neurological signs, but not earlier. In contrast, 14-3-3ϵ and -η isoforms were not detectable. 14-3-3 levels increased with time and were positively correlated with the degree of neurological symptoms. Post-mortem examination of brain samples revealed a positive correlation between PrPres and 14-3-3ϵ levels. Interestingly, florid plaques characteristic of human vCJD could not be detected in diseased monkeys. It was concluded that analysis of 14-3-3 proteins in CSF is a reliable tool to characterize the time course of brain degeneration in simian vCJD. However, there are differences in the clinical course between orally and intracerebrally infected animals that may influence the detection of other biomarkers.

Spontaneous Obesity-Linked Type 2 Diabetes in the Absence of Islet Amyloid in a Cynomolgus Monkey Infected With Bovine Spongiform Encephalopathy

“…At necropsy, a surrogate marker for infectious prions called proteinase K-resistant prion protein (PrP res ) 10 was detected by Western immunoblot 10 or paraffin-embedded tissue (PET) blot 10 in gut-associated lymphoid tissue (GALT) specimens, spleen, lumbar spinal cord segments, the adenohypophysis, and the trigeminal ganglions at both sides. However, PrP res deposits were not detected in the obex, brain stem, or other regions of the brain.…”

“…Macaque R984 belonged to a group of 18 female macaques orally dosed with BSE as part of an European Union-supported BSE risk assessment study. 10 Cerebrospinal fluid (CSF) samples were collected at regular intervals for analysis of 14-3-3 protein (14-3-3p) as a biomarker of brain damage from all macaques. 10 All CSF samples of macaque R984 remained 14-3-3p negative, and there was no evidence of behavioral changes or ataxia throughout the observation period (data not shown).…”

“…10 Cerebrospinal fluid (CSF) samples were collected at regular intervals for analysis of 14-3-3 protein (14-3-3p) as a biomarker of brain damage from all macaques. 10 All CSF samples of macaque R984 remained 14-3-3p negative, and there was no evidence of behavioral changes or ataxia throughout the observation period (data not shown). Therefore, macaque R984 represented a preclinical stage of prion disease.…”

Reduction of PrPC in human cerebrospinal fluid after spinal cord injury

“…14-3-3 is an abundant protein of the central nervous system and the presence of 14-3-3 proteins in CSF samples is a clinical biomarker for extensive and rapid neuronal destruction (e.g., prion disease, dementia). 43 This diagnostic test is currently used as the leading preliminary screen for prion diseases; however, it is used in combination with other diagnostic criteria due to the overlap between prion diseases and other conditions that elevate CSF levels of 14-3-3. None of the CSF samples evaluated, shows PrP C levels were lower in four spinal cord injured patients compared to control patients and that the 37 kDa band is the major species in the CSF samples.…”

Scientific Opinion on a request for a review of a scientific publication concerning the zoonotic potential of ovine scrapie prions

“…However, even with the small number of animals challenged, there was some minor variation in outcome, which may be related to the fact that different source isolates were used. When cynomolgus monkeys homozygous for methionine at codon 129 were challenged orally or intracerebrally with bovine BSE (Yutzy et al, 2007;Holznagel et al, 2013) they developed spongiform encephalopathy without the florid plaques that characterise human vCJD (Ironside, 1998), whereas such plaques were described in a separate challenge of cynomolgus monkeys with BSE (Lasmezas et al, 1996). Western blotting demonstrated a PrP profile with characteristic non-glycosylated double bands in brain homogenates digested with PK.…”