Table 1.
Patient demographics.
Fig 1.
Psychosine content and GALC activity in neurodegenerative cohort.
Psychosine concentration in white (WM) and gray (GM) cortical matter, substantia nigra, and caudate was examined in patients diagnosed with Parkinson’s, Alzheimer’s, Krabbe, or healthy controls. A-D) Psychosine was found to have a robust distribution, elevated in the white matter and substantia nigra of all patients. E-H) Psychosine in white and gray matter of Parkinson’s brains trended upwards compared to AD and healthy controls but did not reach significance. GALC activity in white (WM) and gray (GM) cortical matter, substantia nigra, and caudate was examined in patients diagnosed with Parkinsons’s, Alzheimer’s, Krabbe’s, or healthy controls. I-L) GALC activity was found to have a robust distribution, with lower levels found in the white matter and substantia nigra of all patients. M-P) GALC activity in white matter of Parkinson’s brains trended downwards compared to AD and healthy controls but did not reach significance. Q) Total cortical psychosine (summation of white and gray matter of cortex) found higher levels (p = 0.0554) of psychosine in Parkinson’s tissue compared to healthy controls. R) A total cortical GALC activity (summation of white and gray matter of cortex) did not find significantly different levels of GALC activity in Parkinson’s tissue compared to healthy controls. S) Correlation of psychosine to GALC activity as measured within the total cortical tissue of each group. (panel A-P: one way ANOVA with Tukey’s multiple comparison test, *p<0.05. **p<0.01, ***p<0.001, ****p<0.0001, panel Q,R: t-test).
Fig 2.
Psychosine content and GALC activity in neuropsychiatric cohort.
Psychosine content and GALC activity was measured in white (WM) and gray (GM) matter of the cortex in patients diagnosed with schizophrenia, bipolar disorder, depression, or as age-matched healthy controls. A,D) The same robust distribution of psychosine and GALC activity was observed in this cohort as found in the older neurodegenerative cohort. B,C,E,F) No significant changes in psychosine content or GALC activity were observed between any disease state. (One way ANOVA with Tukey’s multiple comparison test, *p<0.05. **p<0.01, ***p<0.001, ****p<0.0001).
Fig 3.
Psychosine content and GALC activity correlated with aging in mid-aged cohort.
Psychosine content (A,B) and GALC activity (C,D) in cortical brain tissue from a combined cohort of mid-aged neuropsychiatric patients and healthy control patient tissue was compared to age at time of death. Linear regression revealed a significant positive correlation between psychosine content in the white matter (A) and age in this cohort, but a similar positive correlation did not reach significance in grey matter (B). However, a significant negative correlation between GALC activity and age was present in both white (C) and grey (D) matter. (Statistical test of slope significantly non-zero, *p<0.05).
Table 2.
GALC mutational analysis.
Fig 4.
GALC mutational effect on psychosine accumulation.
Severe GALC mutations were identified in 2 patients diagnosed with Parkinson’s disease (PD). Psychosine levels in tissue from these two patients were elevated compared to that measured in tissue from PD patients without a severe GALC mutation.
Fig 5.
Immunohistological staining for α-synuclein.
Immunohistological staining for α-synuclein was performed in brain tissue from 3 infantile KD patients (A-C), a late-onset KD patient (D), 2 patients found to be GALC mutation/variant carriers with no neurological disorders previously diagnosed (E,F), a Parkinson’s patient (G), and a healthy control with no GALC mutations (H). Accumulations of α-synuclein were observed in all Krabbe patients (A-D), the Parkinson’s brain (G), and also within the brains of GALC mutation/variant carriers (E,F). Accumulations in the infantile brains were abundant but smaller in size than the Lewy bodies observed in the Parkinson’s brain and the α-synuclein accumulations found in late-onset KD and GALC mutation carrier tissue. No significant α-synuclein accumulation was observed in the healthy diagnosed patient without GALC mutations (H). A secondary control experiment confirmed the specificity of the secondary antibody (I). Scale Bars: 100 μm.