Cerebrospinal fluid and serum glycosphingolipid biomarkers in canine globoid cell leukodystrophy (Krabbe Disease)

Abstract

Globoid cell leukodystrophy (GLD, Krabbe disease, Krabbe's disease) is caused by genetic mutations in the gene encoding, galactosylceramidase (GALC). Deficiency of this enzyme results in central and peripheral nervous system pathology, and is characterized by loss of myelin and an infiltration of globoid cells. The canine model of GLD provides a translational model which faithfully recapitulates much of the human disease pathology. Targeted lipidomic analysis was conducted in serum and cerebrospinal fluid (CSF) over the lifetime of GLD affected and normal canines, and in brain tissue at humane endpoint to better understand disease progression and identify potential biomarkers of disease. Psychosine, a substrate of GALC and primary contributor to the pathology in GLD, was observed to be significantly elevated in the serum and CSF by 2 or 4 weeks of age, respectively, and steadily increased over the lifetime of affected animals. Importantly, psychosine concentration strongly correlated with disease severity. Galactosylceramide, glucosylceramide, and lactosylceramide were also found to be elevated in the CSF of affected animals and increased with age. Psychosine and galactosylceramide were found to be significantly increased in brain tissue at humane endpoint. This study identified several biomarkers which may be useful in the development of therapeutics for GLD.

Krabbe disease successfully treated via monotherapy of intrathecal gene therapy

“…Cerebrospinal fluid psychosine, galactosylceramide, and total protein concentrations are normalized in GLD dogs treated presymptomatically with 1 × 10 14 vg AAV9-cGALC. Similar to recent findings in untreated GLD dogs (16), cerebrospinal fluid (CSF) psychosine concentrations were elevated in IS-only dogs at 4 weeks of age and increased with disease progression ( Figure 3A). Psychosine was not detectable in the CSF of normal dogs at any time point.…”

“…In Krabbe disease patients, psychosine is a diagnostic marker of phenotype severity and treatment effect (30,31). Similarly, we have shown that CSF psychosine increased early and steadily in untreated GLD and strongly correlated with disease progression (16). In the 2Wk-Low cohort, detection of psychosine in the CSF was delayed until 12 weeks of age.…”

“…In contrast, variability was seen within the IS-only and 2Wk-Low cohorts, which were followed until humane endpoint. We recently reported that CSF psychosine concentrations vary and closely correlate with disease progression in GLD dogs (16), and this is likely true for tissues. Interestingly, the youngest dog to develop pelvic jci.org Volume 130 Number 9 September 2020 treats CNS disease, intracisternal administration of AAV-GALC improved both CNS and PNS myelination.…”

Krabbe disease: New hope for an old disease

“…The canine GALC gene was cloned and the genetic deficiency revealed in 1996 [ 24 ]. In recent years a number of natural history studies have been conducted in the Krabbe dog including electrophysiological, imaging, and biochemical markers of disease progression [ 24 , 28 – 30 ]. These benchmark studies greatly increased the utility of this model and paved the way for meaningful therapeutic evaluations in a more relevant species.…”

Mechanisms of demyelination and neurodegeneration in globoid cell leukodystrophy

“…In the experimental autoimmune encephalomyelitis (EAE) model, sphingolipid lactosylceramide stimulates astrocytes (Mayo et al, 2014) and recruits microglia and infiltrating macrophages. In the canine GLD model, lactosylceramide was highly elevated in the cerebrospinal fluid and further increased with age, in addition to psychosine and GalCer (Corado et al, 2020), indicating a possibility of the contribution of accumulated lactosylceramide to GLD pathology.…”