Synaptic loss is a feature of multiple sclerosis pathology that can be seen even in normal-appearing gray matter. Opsonization of synapses with complement components may underlie pathologic synapse loss.
Objective:
We sought to determine whether circulating neuronal-enriched and astrocytic-enriched extracellular vesicles (NEVs and AEVs) provide biomarkers reflecting complement-mediated synaptic loss in multiple sclerosis.
Methods:
From plasma of 61 people with multiple sclerosis (46 relapsing–remitting multiple sclerosis (RRMS) and 15 progressive MS) and 31 healthy controls, we immunocaptured L1CAM + NEVs and GLAST + AEVs. We measured pre- and post-synaptic proteins synaptopodin and synaptophysin in NEVs and complement components (C1q, C3, C3b/iC3b, C4, C5, C5a, C9, Factor B, and Factor H) in AEVs, total circulating EVs, and neat plasma.
Results:
We found lower levels of NEV synaptopodin and synaptophysin in MS compared to controls (p < 0.0001 for both). In AEVs, we found higher levels of multiple complement cascade components in people with MS compared to controls; these differences were not noted in total EVs or neat plasma. Strikingly, there were strong inverse correlations between NEV synaptic proteins and multiple AEV complement components in MS, but not in controls.
Conclusion:
Circulating EVs could identify synaptic loss in MS and suggest a link between astrocytic complement production and synaptic loss.
ReichDSLucchinettiCFCalabresiPA.Multiple sclerosis. N Engl J Med2018; 378(2): 169–180.
2.
JurgensTJafariMKreutzfeldtM, et al. Reconstruction of single cortical projection neurons reveals primary spine loss in multiple sclerosis. Brain2016; 139(Pt. 1): 39–46.
3.
DuttaRChangADoudMK, et al. Demyelination causes synaptic alterations in hippocampi from multiple sclerosis patients. Ann Neurol2011; 69(3): 445–454.
4.
WegnerCEsiriMMChanceSA, et al. Neocortical neuronal, synaptic, and glial loss in multiple sclerosis. Neurology2006; 67(6): 960–967.
5.
MandolesiGGentileAMusellaA, et al. Synaptopathy connects inflammation and neurodegeneration in multiple sclerosis. Nat Rev Neurol2015; 11(12): 711–724.
6.
ChungWSWelshCABarresBA, et al. Do glia drive synaptic and cognitive impairment in disease?Nat Neurosci2015; 18(11): 1539–1545.
7.
NorisMRemuzziG.Overview of complement activation and regulation. Semin Nephrol2013; 33(6): 479–492.
8.
VeerhuisRNielsenHMTennerAJ.Complement in the brain. Mol Immunol2011; 48(14): 1592–1603.
9.
StevensBAllenNJVazquezLE, et al. The classical complement cascade mediates CNS synapse elimination. Cell2007; 131(6): 1164–1178.
10.
HongSBeja-GlasserVFNfonoyimBM, et al. Complement and microglia mediate early synapse loss in Alzheimer mouse models. Science2016; 352(6286): 712–716.
11.
WerneburgSJungJKunjammaRB, et al. Targeted complement inhibition at synapses prevents microglial synaptic engulfment and synapse loss in demyelinating disease. Immunity2020; 52: 841601.
12.
WatkinsLMNealJWLovelessS, et al. Complement is activated in progressive multiple sclerosis cortical grey matter lesions. J Neuroinflammation2016; 13(1): 161.
13.
IngramGLovelessSHowellOW, et al. Complement activation in multiple sclerosis plaques: An immunohistochemical analysis. Acta Neuropathol Commun2014; 2: 53.
14.
MichailidouIWillemsJGPKooiE-J, et al. Complement C1q-C3-associated synaptic changes in multiple sclerosis hippocampus. Ann Neurol2015; 77(6): 1007–1026.
15.
FitzgeraldKCKimKSmithMD, et al. Early complement genes are associated with visual system degeneration in multiple sclerosis. Brain2019; 142(9): 2722–2736.
16.
LiddelowSAGuttenplanKAClarkeLE, et al. Neurotoxic reactive astrocytes are induced by activated microglia. Nature2017; 541(7638): 481–487.
17.
MathieuMMartin-JaularLLavieuG, et al. Specificities of secretion and uptake of exosomes and other extracellular vesicles for cell-to-cell communication. Nat Cell Biol2019; 21(1): 9–17.
18.
JiaLQiuQZhangH, et al. Concordance between the assessment of Aβ42, T-tau, and P-T181-tau in peripheral blood neuronal-derived exosomes and cerebrospinal fluid. Alzheimer Dement2019; 15(8): 1071–1080.
19.
FiandacaMSKapogiannisDMapstoneM, et al. Identification of preclinical Alzheimer’s disease by a profile of pathogenic proteins in neurally derived blood exosomes: a case-control study. Alzheimers. Dement2015; 11: 600–607.e1.
20.
KapogiannisDMustapicMShardellMD, et al. Association of extracellular vesicle biomarkers with Alzheimer disease in the Baltimore longitudinal study of aging. JAMA Neurol2019: 1340–1351.
21.
AthaudaDGulyaniSKarnatiH, et al. Utility of neuronal-derived exosomes to examine molecular mechanisms that affect motor function in patients with Parkinson disease: A secondary analysis of the exenatide-PD trial. JAMA Neurol2019; 76(4): 420–429.
22.
ChawlaSGulyaniSAllenRP, et al. Extracellular vesicles reveal abnormalities in neuronal iron metabolism in restless legs syndrome. Sleep2019; 42(7): zsz079.
23.
GoetzlEJElahiFMMustapicM, et al. Altered levels of plasma neuron-derived exosomes and their cargo proteins characterize acute and chronic mild traumatic brain injury. FASEB J2019; 33(4): 5082–5088.
24.
MustapicMEitanEWernerJKJr, et al. Plasma extracellular vesicles enriched for neuronal origin: a potential window into brain pathologic processes. Front Neurosci2017; 11: 278.
25.
GoetzlEJBoxerASchwartzJB, et al. Altered lysosomal proteins in neural-derived plasma exosomes in preclinical Alzheimer disease. Neurology2015; 85(1): 40–47.
26.
KapogiannisDBoxerASchwartzJB, et al. Dysfunctionally phosphorylated type 1 insulin receptor substrate in neural-derived blood exosomes of preclinical Alzheimer’s disease. FASEB J2014; 29(2): 589–596.
27.
GoetzlEJKapogiannisDSchwartzJB, et al. Decreased synaptic proteins in neuronal exosomes of frontotemporal dementia and Alzheimer’s disease. FASEB J2016; 30: 4141A8.
28.
GoetzlEJSchwartzJBAbnerEL, et al. High complement levels in astrocyte-derived exosomes of Alzheimer disease. Ann Neurol2018; 83(3): 544–552.
29.
BhargavaPNogueras-OrtizCChawlaS, et al. Altered levels of toll-like receptors in circulating extracellular vesicles in multiple sclerosis. Cells2019; 8(9): 1058.
30.
WitwerKWBuzasEIBemisLT, et al. Standardization of sample collection, isolation and analysis methods in extracellular vesicle research. J Extracell Vesicles2013; 2: 20360.
31.
WitwerKWSoekmadjiCHillAF, et al. Updating the MISEV minimal requirements for extracellular vesicle studies: Building bridges to reproducibility. J Extracell Vesicles2017; 6(1): 1396823.
32.
GoetzlEJAbnerELJichaGA, et al. Declining levels of functionally specialized synaptic proteins in plasma neuronal exosomes with progression of Alzheimer’s disease. FASEB J2017: fj201700731R.
33.
IngramGHakobyanSHirstCL, et al. Complement regulator factor H as a serum biomarker of multiple sclerosis disease state. Brain2010; 133(Pt. 6): 1602–1611.
34.
IngramGHakobyanSHirstCL, et al. Systemic complement profiling in multiple sclerosis as a biomarker of disease state. Mult Scler2012; 18(10): 1401–1411.
