TY  - JOUR
AU  - Kadam, Vaibhavi
AU  - Wacker, Madeleine
AU  - Oeckl, Patrick
AU  - Korneck, Milena
AU  - Dannenmann, Benjamin
AU  - Skokowa, Julia
AU  - Hauser, Stefan
AU  - Otto, Markus
AU  - Synofzik, Matthis
AU  - Mengel, David
TI  - Most L1CAM Is not Associated with Extracellular Vesicles in Human Biofluids and iPSC-Derived Neurons.
JO  - Molecular neurobiology
VL  - 62
IS  - 8
SN  - 0893-7648
CY  - Totowa, NJ
PB  - Humana Press
M1  - DZNE-2025-00896
SP  - 10427 - 10442
PY  - 2025
AB  - Transmembrane L1 cell adhesion molecule (L1CAM) is widely used as a marker to enrich for neuron-derived extracellular vesicles (EVs), especially in plasma. However, this approach lacks sufficient robust validation. This study aimed to assess whether human biofluids are indeed enriched for EVs, particularly neuron-derived EVs, by L1CAM immunoaffinity, utilizing multiple sources (plasma, CSF, conditioned media from iPSC-derived neurons [iNCM]) and different methods (mass spectrometry [MS], nanoparticle tracking analysis [NTA]). Following a systematic multi-step validation approach, we confirmed isolation of generic EV populations using size-exclusion chromatography (SEC) and polymer-aided precipitation (PPT)-two most commonly applied EV isolation methods-from all sources. Neurofilament light (NfL) was detected in both CSF and blood-derived EVs, indicating their neuronal origin. However, L1CAM immunoprecipitation did not yield enrichment of L1CAM in EV fractions. Instead, it was predominantly found in its free-floating form. Additionally, MS-based proteomic analysis of CSF-derived EVs also did not show L1CAM enrichment. Our study validates EV isolation from diverse biofluid sources by several isolation approaches and confirms that some EV subpopulations in human biofluids are of neuronal origin. Thorough testing across multiple sources by different orthogonal methods, however, does not support L1CAM as a marker to reliably enrich for a specific subpopulation of EVs, particularly of neuronal origin.
KW  - Humans
KW  - Extracellular Vesicles: metabolism
KW  - Neural Cell Adhesion Molecule L1: metabolism
KW  - Neurons: metabolism
KW  - Induced Pluripotent Stem Cells: metabolism
KW  - Induced Pluripotent Stem Cells: cytology
KW  - Proteomics
KW  - Body Fluids: metabolism
KW  - Biomarkers (Other)
KW  - Blood (Other)
KW  - Cerebrospinal fluid (Other)
KW  - Extracellular vesicles (Other)
KW  - Immunoprecipitation (Other)
KW  - Isolation methods (Other)
KW  - L1CAM (Other)
KW  - Neuron (Other)
KW  - Neural Cell Adhesion Molecule L1 (NLM Chemicals)
KW  - L1CAM protein, human (NLM Chemicals)
LB  - PUB:(DE-HGF)16
C6  - pmid:40210837
DO  - DOI:10.1007/s12035-025-04909-2
UR  - https://pub.dzne.de/record/280113
ER  -