Age- and disease-related changes in brain proteins and sugar molecules have been mapped using a spatial mass spectrometry workflow designed to analyze small regions of tissue directly on microscope slides.
The approach, developed by scientists at Boston University Chobanian & Avedisian School of Medicine, combines on-slide enzymatic digestion with liquid chromatography data-independent acquisition tandem mass spectrometry (LC-DIA-MS/MS) to profile both proteins and glycans from defined areas of brain tissue. Compared with earlier data-dependent acquisition workflows, the method expands molecular coverage, enabling deeper analysis of glycosylated proteins and extracellular matrix components linked to neurodegeneration.
Glycosylation and extracellular matrix remodeling are increasingly implicated in brain aging and neurodegeneration. However, their molecular signatures have remained relatively underexplored in large-scale brain tissue studies.
“Our study elucidates how the brain changes with aging and with diseases such as Alzheimer’s disease in the presence or absence of Lewy body pathology at a highly detailed molecular level,” said corresponding author Manveen Sethi, Assistant Professor of Biochemistry and Cell Biology at Boston University, in a press release. “Understanding these changes is important because they begin years before symptoms such as memory loss or movement problems appear.”
To generate these data, the team analyzed brain samples from young and aged mice alongside postmortem human brain tissue from individuals with Lewy body disease, with or without Alzheimer’s disease co-pathology. In each case, enzymes were applied to small regions of tissue mounted on glass slides to release glycans and peptides directly from the surface, enabling targeted extraction and LC-MS/MS analysis of the released molecules.
The workflow identified more than 4,000 proteins – two to three times more than earlier approaches – revealing molecular differences linked to aging and neurodegenerative pathology. In aged mouse brains, synapse-related proteins such as SYNPR, ZNT3, and HPCA increased in abundance, reflecting age-associated synaptic remodeling.
In human tissue, Alzheimer’s disease co-occurring with Lewy body pathology was associated with altered extracellular matrix proteins, glycosylated proteins, and mitochondrial pathways – along with reduced levels of certain chondroitin sulfate glycans in brainstem tissue.
The researchers suggest the workflow could be applied to a wide range of neurological studies, enabling spatially resolved glycomic and proteomic profiling from small clinical tissue samples.
“Our hope is that this research will provide scientists with a robust and high-resolution spatial mass spectrometry glycomic and proteomic workflow from minimal tissue,” Sethi said. “This framework could help support biomarker discovery and improved diagnosis and treatments.”
Newsletters
Receive the latest analytical science news, personalities, education, and career development – weekly to your inbox.
