Disease vs Normal Comparative Spatial Lipidomics Service

This study investigates region-specific lipid metabolism alterations in Parkinson's disease (PD) using the gold-standard MPTP primate model. While prior lipidomic research linked lipid abnormalities to PD pathology, it lacked spatial resolution due to bulk tissue analysis. This work addresses this gap by applying spatial lipidomics to map region-specific sulfatide changes in MPTP-lesioned monkey brains.

Sample Design: Brain tissues from 5 control and 5 MPTP-treated rhesus monkeys (Macaca mulatta) were analyzed. All animals were euthanized 6 months after initial MPTP exposure, and brain tissues were rapidly frozen for preservation.

Technical Methods:

• Bipolar (positive and negative ion modes) matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry imaging (MALDI-FTICR-MSI)
• Spatial resolution of 150 μm, analyzing coronal brain sections at the level of -6 mm from the anterior commissure posterior
• Norharmane was used as the matrix
• Luxol fast blue staining was applied to validate myelin distribution

Data Analysis Workflow:

• SCiLS Lab software was used to annotate specific brain regions (e.g., external/internal globus pallidus, substantia nigra pars reticulata)
• Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were applied to identify differential lipids
• MS/MS analysis was performed to confirm lipid molecular identities
• Multivariate t-tests were used to evaluate significant intergroup differences

1. Region-specific distribution of sulfatides:

Hydroxylated sulfatides (e.g., SHexCer(t42:2), SHexCer(t42:1)) were predominantly enriched in gray matter regions, particularly in motor-related areas (caudate nucleus, putamen, precentral gyrus) and temporal cortical regions. Non-hydroxylated sulfatides (e.g., SHexCer(d42:2), SHexCer(d42:1)) were mainly distributed in white matter regions (periventricular white matter, optic tract, internal capsule). With increasing chain length, the relative abundance of hydroxylated forms increased in gray matter (Figure 3).

Figure 3. Distributions of hydroxylated and non-hydroxylated sulfatides and hexosylceramides in macaque brain tissue sections. a [SHexCer (d42:2)-H]⁻, b [SHexCer (t42:2)-H]⁻, c [SHexCer (t42:2)-H]⁻ normalized to [SHexCer (d42:2)-H]⁻, d [SHexCer (d42:1)-H]⁻, e [SHexCer (t42:1)-H]⁻, f [SHexCer (t42:1)-H]⁻ normalized to [SHexCer (d42:1)-H]⁻, g [HexCer (d42:2) + K]⁺, h [HexCer (t42:2) + K]⁺, i [HexCer (t42:2) + K]⁺ normalized to [HexCer (d42:2) + K]⁺, j [HexCer (d42:1) + K]⁺, and k [HexCer (t42:1) + K]⁺]. l [HexCer (t42:1) + K]⁺ normalized to [HexCer (d42:1) + K]⁺.

2. MPTP-induced lipid alterations:

Long-chain polyunsaturated hydroxylated sulfatides were significantly decreased in motor-related brain regions (external/internal globus pallidus, substantia nigra pars reticulata) of MPTP-lesioned animals. Conversely, long-chain non-hydroxylated sulfatides were significantly increased in the same brain regions. Figure 4 shows the relative abundance changes of sulfatides in specific brain regions (globus pallidus, substantia nigra) between the MPTP-treated group and the control group, visually presenting the decrease in long-chain hydroxylated sulfatides and the increase in non-hydroxylated forms through heatmaps and statistical charts.

Figure 5 further validates these region-specific changes through PLS-DA analysis and multivariate statistics, particularly showing that the lipid profile changes are most significant in motor-related brain regions. These changes varied across different brain regions, indicating region-specific lipid metabolic dysregulation.

Figure 4. Targeted statistical data analysis of hydroxylated and non-hydroxylated sulfatides.

Figure 5. MALDI-MS ion distribution images of sulfatides that showed significant differences between control (left) and MPTP-lesioned (right) brain sections. [SHexCer (t41:2)-H]⁻, b [SHexCer (t42:2)-H]⁻, c [SHexCer (t42:3)-H]⁻, d [SHexCer (t43:2)-H]⁻, e [SHexCer (d40:1)-H]⁻, f [SHexCer (d40:2)-H]⁻, g [SHexCer (d42:1)-H]⁻, h [SHexCer (d41:1)-H]⁻.

3. Spatial distribution of other lipids:

Short-chain phosphatidylserine (PS(36:1) and phosphatidylcholine PC(36:1))were primarily distributed in white matter. Long-chain polyunsaturated phosphatidylinositol (PI(40:6) and phosphatidylethanolamine (PE(40:6)) were mainly found in gray matter (Figure 1).

Figure 1. MALDI-MSI images of glycerophospholipid and sphingolipid species. Dual polarity MALDI-MSI of the same tissue section (shown in a) reveals the ion images of b [PS (36:1)-H]⁻, c [PS (40:6)-H]⁻, d [PC(36:1) + K]⁺, e [PC(40:6) + K]⁺, f [PI (36:4)-H]⁻, g [PI (38:4)-H]⁻, h [PI (40:6)-H]⁻, i [PE-NMe2 (32:0)-H]⁻, j [PE (38:4)-H]⁻, k [PE (38:6)-H]⁻]⁻, l [PE (40:6)-H]⁻, m [PE (P-40:6)-H]⁻, n [SM(d42:2) + H]+, o [SM(d42:1) + K]⁺, p [HexCer(d42:2)+Na]⁺, q [HexCer(d42:1)+Na]⁺, r [SHexCer (d41:1)-H]⁻, s [SHexCer (d43:2)-H]⁻, t [CerP (36:1)-H]⁻, u [GM3 (36:1)-H]⁻, v [GM2 (36:1)-H]⁻, w [GM1 (36:1)-H]⁻, x [GD1 (36:1)+Na-2H]⁻ in a coronal control macaque brain tissue section.

This pioneering study employs high-resolution MALDI-MSI to map lipid distribution in a primate PD model, establishing new standards for spatial lipidomics. It challenges the neuron-centric view of PD by revealing critical myelin lipid dysregulation, with hydroxylated/non-hydroxylated sulfatide ratios offering promising biomarker potential. The research identifies peroxisomal function and sulfatide metabolism as novel therapeutic targets for myelin protection, with implications extending to Alzheimer's and Huntington's diseases. Using non-human primates provides superior translational relevance compared to rodent models, creating an essential bridge from basic research to clinical applications.