The chaperone protein clusterin may serve as a cerebrospinal fluid biomarker for chronic spinal cord disorders in the dog

Abstract

Chronic spinal cord dysfunction occurs in dogs as a consequence of diverse aetiologies, including long-standing spinal cord compression and insidious neurodegenerative conditions. One such neurodegenerative condition is canine degenerative myelopathy (DM), which clinically is a challenge to differentiate from other chronic spinal cord conditions. Although the clinical diagnosis of DM can be strengthened by the identification of the Sod1 mutations that are observed in affected dogs, genetic analysis alone is insufficient to provide a definitive diagnosis. There is a requirement to identify biomarkers that can differentiate conditions with a similar clinical presentation, thus facilitating patient diagnostic and management strategies. A comparison of the cerebrospinal fluid (CSF) protein gel electrophoresis profile between idiopathic epilepsy (IE) and DM identified a protein band that was more prominent in DM. This band was subsequently found to contain a multifunctional protein clusterin (apolipoprotein J) that is protective against endoplasmic reticulum (ER) stress-mediated apoptosis, oxidative stress, and also serves as an extracellular chaperone influencing protein aggregation. Western blot analysis of CSF clusterin confirmed elevated levels in DM compared to IE (p < 0.05). Analysis of spinal cord tissue from DM and control material found that clusterin expression was evident in neurons and that the clusterin mRNA levels from tissue extracts were elevated in DM compared to the control. The plasma clusterin levels was comparable between these groups. However, a comparison of clusterin CSF levels in a number of neurological conditions found that clusterin was elevated in both DM and chronic intervertebral disc disease (cIVDD) but not in meningoencephalitis and IE. These findings indicate that clusterin may potentially serve as a marker for chronic spinal cord disease in the dog; however, additional markers are required to differentiate DM from a concurrent condition such as cIVDD.

Preliminary assessment of serum clusterin as a potential biomarker for canine lymphoma

“…The presence of CLU in individual serum samples was initially evaluated via western blot analysis, as previously described. 47,48 In brief, protein concentrations of the serum samples were determined using a bicinchoninic acid (BCA) protein assay system (Thermo Life Science Ltd, UK); 10ug aliquots of each sample were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS -PAGE) using Criterion 26 well gels (BioRad Ltd, UK), and then transferred to nitrocellulose membranes using the iBlot system (Invitrogen, Thermo Fisher, UK). Samples from diseased and control dogs were loaded in alternate wells, with protein molecular weight standards (BioRad Ltd, UK) run in the first and last well of each gel.…”

Cerebrospinal Fluid Levels of Phosphorylated Neurofilament Heavy as a Diagnostic Marker of Canine Degenerative Myelopathy

“…While CSF protein constituents have been increased in DM‐affected dogs, none have shown specificity for DM . Diagnosis of DM is most challenging in dogs with a genetic predisposition for DM and concurrent acquired myelopathy.…”

“…While CSF protein constituents have been increased in DM-affected dogs, none have shown specificity for DM. 28,29 Diagnosis of DM is most challenging in dogs with a genetic predisposition for DM and concurrent acquired myelopathy. As the majority of dogs in the DM mimic cohort had clinical signs secondary to Hansen type 2 intervertebral disk herniation, the high specificity of increased CSF pNF-H concentration to DM is large in comparison with compressive myelopathy.…”

Proteomic analysis of cerebrospinal fluid in California sea lions (Zalophus californianus) with domoic acid toxicosis identifies proteins associated with neurodegeneration

“…The second aim of this study was to demonstrate that the sea lion CSF proteome is dynamic and should be considered a resource for biomarker discovery in sea lions with toxin‐induced epilepsy. Because the CSF bathes the central nervous system, this fluid has been the focus of numerous biomarker studies for epilepsy and excitotoxicity . Although sampling CSF is more invasive and carries additional risk, the CSF proteome contains mechanistic information that can be used to better understand the pathophysiological continuum of neurological disease.…”