Genetic Risk Variant for Multiple Sclerosis drives Astrocyte - PowerPoint PPT Presentation

Genetic Risk Variant for Multiple Sclerosis drives Astrocyte Responses associated with Lesion Formation. Gerald Ponath Department of Neurology Yale School of Medicine gerald.ponath@yale.edu

Genome-wide association study of MS susceptibility 47,000 MS patients 68,000 controls • > 200 risk variants • Highly significant, but small odds ratio • Dysregulation of lymphocytes Housley et al. Sci Trans Med 2015 NF-κB signaling in stimulated CD4 + cells p50 expression in unstimulated PBMCs

MS risk variants can affect CNS cell function, i.e. MS susceptibility is conferred through CNS-intrinsic pathways. Astrocytes ROS production glutamate uptake CCL2, 5, 7, 8, 12 CXCL1, 9, 10, 12, 16 myelin uptake IL1 β, 6, 7, 11, 15 TNF ⍺ ICAM-1 GFAP/hematoxylin The NF-κB related risk variant, rs7665090, drives excessive astrocyte-mediated lymphocyte recruitment.

Chromatin accessibility in the NFKB1/MANBA risk haplotype block in astrocytes and T cells Normalized ATAC-seq profiles in the NFKB1/MANBA risk locus are similar in unstimulated and stimulated human astrocytes and in effector and regulatory T cells.

Impact of the rs7665090-G risk variant on NF-κB expression and signaling in iPSC-derived astrocytes NF-κB expression genotyped MS patients rs7665090-GG rs7665090-AA NF-κB signaling

Impact of rs7665090-G on NF-κB target genes in iPSC-derived astrocytes NF-κB target gene expression NF-κB target protein expression NF-κB signaling C3 CCL2, 5, 7, 8, 12 “A1” phenotype CXCL1, 9, 10, 12, 16 IL1 β, 6, 7, 11, 15 TNF ⍺ ICAM-1 C3 is a marker for neurotoxic, reactive (A1) astrocytes Liddelow et al. Nature 2017

Impact of the NF-κB relevant rs7665090 risk variant on astrocyte responses in MS tissue white matter lesions genotyped MS tissue genotyped MS patients rs7665090 risk/protective variants iPSC-derived astrocytes rs7665090 risk/protective variants CD68

Impact of the rs7665090 risk variant on astrocytic NF-κB expression in white matter lesions NF-κB p50/p65 expression in the cytosol/nucleus of hypertrophic astrocytes

Impact of the rs7665090 risk variant on astrocyte responses in white matter lesions Expression of immune mediators and activation markers in hypertrophic astrocytes upregulation no upregulation

Impact of the rs7665090 risk variant on MS lesion pathology Lymphocytic infiltration in MS lesions MS lesion size (histology) Lesion load (MRI) 18 lesions (6 cases); protective 35 MS patients; protective 21 lesions (8 cases); risk 40 MS patients; risk

Summary tes iPSC-derived astrocytes SNP epigenetic studies astrocytic phenotype GWAS lesion load astrocytic phenotype lesion phenotype NF-κB expression/ signaling lymphocyte recruitment lesion load chemokine secretion lesion size neurotoxic (A1) phenotype astrocyte/axon metabolic coupling change in susceptibility << astrocytic response (culture) < astrocyte response (lesion)

tes iPSC-derived astrocytes SNP epigenetic studies astrocytic phenotype GWAS lesion load astrocytic phenotype lesion phenotype Outlook • Systematic correlation of MS risk variants with chromatin landscapes of CNS cells • Identification of risk variants that impact on CNS cells and of CNS-intrinsic disease-causing pathways • MS patients carrying specific risk variants may benefit from therapeutic inhibition of risk variant-regulated pathways

Pitt Lab David Pitt Mayyan Mubarak Somiah Dahlawi Calvin Park Sarah Wang David Hafler Yale Neurology Matt Lincoln and Genetics Tomokazu Sumida Chris Cotsapas