TY - JOUR
T1 - Complement Component C3 Loss leads to Locomotor Deficits and Altered Cerebellar Internal Granule Cell In Vitro Synaptic Protein Expression in C57BL/6 Mice
AU - DeKorver, Nicholas W.
AU - Chaudoin, Tammy R.
AU - Zhao, Gang
AU - Wang, Dong
AU - Arikkath, Jyothi
AU - Bonasera, Stephen J.
N1 - Publisher Copyright:
© 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
PY - 2021/11
Y1 - 2021/11
N2 - Complement component 3 (C3) expression is increased in the cerebellum of aging mice that demonstrate locomotor impairments and increased excitatory synapse density. However, C3 regulation of locomotion, as well as C3 roles in excitatory synapse function, remains poorly understood. Here, we demonstrate that constitutive loss of C3 function in mice evokes a locomotor phenotype characterized by decreased speed, increased active state locomotor probability, and gait ataxia. C3 loss does not alter metabolism or body mass composition. No evidence of significant muscle weakness or degenerative arthritis was found in C3 knockout mice to explain decreased gait speeds. In an enriched primary cerebellar granule cell culture model, loss of C3 protein results in increased excitatory synaptic density and increased response to KCl depolarization. Our analysis of excitatory synaptic density in the cerebellar internal granule cell and molecular layers did not demonstrate increased synaptic density in vivo, suggesting the presence of compensatory mechanisms regulating synaptic development. Functional deficits in C3 knockout mice are therefore more likely to result from altered synaptic function and/or connectivity than gross synaptic deficits. Our data demonstrate a novel role for complement proteins in cerebellar regulation of locomotor output and control.
AB - Complement component 3 (C3) expression is increased in the cerebellum of aging mice that demonstrate locomotor impairments and increased excitatory synapse density. However, C3 regulation of locomotion, as well as C3 roles in excitatory synapse function, remains poorly understood. Here, we demonstrate that constitutive loss of C3 function in mice evokes a locomotor phenotype characterized by decreased speed, increased active state locomotor probability, and gait ataxia. C3 loss does not alter metabolism or body mass composition. No evidence of significant muscle weakness or degenerative arthritis was found in C3 knockout mice to explain decreased gait speeds. In an enriched primary cerebellar granule cell culture model, loss of C3 protein results in increased excitatory synaptic density and increased response to KCl depolarization. Our analysis of excitatory synaptic density in the cerebellar internal granule cell and molecular layers did not demonstrate increased synaptic density in vivo, suggesting the presence of compensatory mechanisms regulating synaptic development. Functional deficits in C3 knockout mice are therefore more likely to result from altered synaptic function and/or connectivity than gross synaptic deficits. Our data demonstrate a novel role for complement proteins in cerebellar regulation of locomotor output and control.
KW - Ataxia
KW - Bone density
KW - C3
KW - Cerebellum
KW - Complement component 3
KW - Gait speed
KW - Grip strength
KW - Internal granule cell
KW - Microtomography
KW - Vgat
KW - Vglut1
UR - http://www.scopus.com/inward/record.url?scp=85113189635&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85113189635&partnerID=8YFLogxK
U2 - 10.1007/s12035-021-02480-0
DO - 10.1007/s12035-021-02480-0
M3 - Article
C2 - 34415487
AN - SCOPUS:85113189635
SN - 0893-7648
VL - 58
SP - 5857
EP - 5875
JO - Molecular Neurobiology
JF - Molecular Neurobiology
IS - 11
ER -