TY - JOUR
T1 - Heterozygous expression of the Alzheimer's disease-protective PLCγ2 P522R variant enhances Aβ clearance while preserving synapses
AU - Solomon, Shiden
AU - Sampathkumar, Nirmal Kumar
AU - Carre, Ivo
AU - Mondal, Mrityunjoy
AU - Chennell, George
AU - Vernon, Anthony C
AU - Ruepp, Marc-David
AU - Mitchell, Jacqueline C
N1 - Funding Information:
This work was supported by the Van Geest Foundation, and the UK Dementia Research Institute which receives its funding from UK DRI Ltd, funded by the UK Medical Research Council, Alzheimer’s Society and Alzheimer’s Research UK.
Publisher Copyright:
© 2022, The Author(s).
PY - 2022/7/27
Y1 - 2022/7/27
N2 - Background: A rare coding variant, P522R, in the phospholipase C gamma 2 (PLCG2) gene has been identified as protective against late-onset Alzheimer’s disease (AD), but the mechanism is unknown. PLCG2 is exclusively expressed in microglia within the central nervous system, and altered microglial function has been implicated in the progression of AD. Methods: Healthy control hiPSCs were CRISPR edited to generate cells heterozygous and homozygous for the PLCG2
P522R variant. Microglia derived from these hiPSC’s were used to investigate the impact of PLCγ2
P522R on disease relevant processes, specifically microglial capacity to take up amyloid beta (Aβ) and synapses. Targeted qPCR assessment was conducted to explore expression changes in core AD linked and microglial genes, and mitochondrial function was assessed using an Agilent Seahorse assay. Results: Heterozygous expression of the P522R variant resulted in increased microglial clearance of Aβ, while preserving synapses. This was associated with the upregulation of a number of genes, including the anti-inflammatory cytokine Il-10, and the synapse-linked CX3CR1, as well as alterations in mitochondrial function, and increased cellular motility. The protective capacity of PLCγ2
P522R appeared crucially dependent on (gene) ‘dose’, as cells homozygous for the variant showed reduced synapse preservation, and a differential gene expression profile relative to heterozygous cells. Conclusion: These findings suggest that PLCγ2
P522R may result in increased surveillance by microglia, and prime them towards an anti-inflammatory state, with an increased capacity to respond to increasing energy demands, but highlights the delicate balance of this system, with increasing PLCγ2
P522R ‘dose’ resulting in reduced beneficial impacts. Graphical abstract: [Figure not available: see fulltext.]
AB - Background: A rare coding variant, P522R, in the phospholipase C gamma 2 (PLCG2) gene has been identified as protective against late-onset Alzheimer’s disease (AD), but the mechanism is unknown. PLCG2 is exclusively expressed in microglia within the central nervous system, and altered microglial function has been implicated in the progression of AD. Methods: Healthy control hiPSCs were CRISPR edited to generate cells heterozygous and homozygous for the PLCG2
P522R variant. Microglia derived from these hiPSC’s were used to investigate the impact of PLCγ2
P522R on disease relevant processes, specifically microglial capacity to take up amyloid beta (Aβ) and synapses. Targeted qPCR assessment was conducted to explore expression changes in core AD linked and microglial genes, and mitochondrial function was assessed using an Agilent Seahorse assay. Results: Heterozygous expression of the P522R variant resulted in increased microglial clearance of Aβ, while preserving synapses. This was associated with the upregulation of a number of genes, including the anti-inflammatory cytokine Il-10, and the synapse-linked CX3CR1, as well as alterations in mitochondrial function, and increased cellular motility. The protective capacity of PLCγ2
P522R appeared crucially dependent on (gene) ‘dose’, as cells homozygous for the variant showed reduced synapse preservation, and a differential gene expression profile relative to heterozygous cells. Conclusion: These findings suggest that PLCγ2
P522R may result in increased surveillance by microglia, and prime them towards an anti-inflammatory state, with an increased capacity to respond to increasing energy demands, but highlights the delicate balance of this system, with increasing PLCγ2
P522R ‘dose’ resulting in reduced beneficial impacts. Graphical abstract: [Figure not available: see fulltext.]
KW - Alzheimer Disease/genetics
KW - Amyloid beta-Peptides/genetics
KW - Humans
KW - Microglia/metabolism
KW - Phospholipase C gamma/genetics
KW - Synapses/metabolism
UR - http://www.scopus.com/inward/record.url?scp=85135083881&partnerID=8YFLogxK
U2 - 10.1007/s00018-022-04473-1
DO - 10.1007/s00018-022-04473-1
M3 - Article
C2 - 35895133
SN - 1420-682X
VL - 79
SP - 453
JO - Cellular and molecular life sciences : CMLS
JF - Cellular and molecular life sciences : CMLS
IS - 8
M1 - 453
ER -