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

Gerald Ponath Department of Neurology Yale School of Medicine

gerald.ponath@yale.edu

Genetic Risk Variant for Multiple Sclerosis drives Astrocyte Responses associated with Lesion Formation.

47,000 MS patients 68,000 controls

• > 200 risk variants
• Highly significant, but small odds ratio
• Dysregulation of lymphocytes

Genome-wide association study of MS susceptibility

Housley et al. Sci Trans Med 2015

p50 expression in unstimulated PBMCs NF-κB signaling in stimulated CD4+ cells

GFAP/hematoxylin

MS risk variants can affect CNS cell function, i.e. MS susceptibility is conferred through CNS-intrinsic pathways.

The NF-κB related risk variant, rs7665090, drives excessive astrocyte-mediated lymphocyte recruitment.

Astrocytes

ICAM-1 CCL2, 5, 7, 8, 12 CXCL1, 9, 10, 12, 16 IL1β, 6, 7, 11, 15 TNF⍺ ROS production glutamate uptake myelin uptake

Chromatin accessibility in the NFKB1/MANBA risk haplotype block in astrocytes and T cells

Normalized ATAC-seq profiles in theNFKB1/MANBA risk locus are similar in unstimulated and stimulated human astrocytes and in effector and regulatory T cells.

rs7665090-GG

genotyped MS patients

rs7665090-AA

Impact of the rs7665090-G risk variant on NF-κB expression and signaling in iPSC-derived astrocytes

NF-κB expression 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

C3 is a marker for neurotoxic, reactive (A1) astrocytes

Liddelow et al. Nature 2017

ICAM-1 CCL2, 5, 7, 8, 12 CXCL1, 9, 10, 12, 16 IL1β, 6, 7, 11, 15 TNF⍺ NF-κB signaling

“A1” phenotype

C3

Impact of the NF-κB relevant rs7665090 risk variant

• n astrocyte responses in MS tissue

rs7665090 risk/protective variants

genotyped MS patients genotyped MS tissue

white matter lesions

CD68

iPSC-derived astrocytes

rs7665090 risk/protective variants

Impact of the rs7665090 risk variant

• n 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

• n astrocyte responses in white matter lesions

Expression of immune mediators and activation markers in hypertrophic astrocytes upregulation no upregulation

Lymphocytic infiltration in MS lesions

Impact of the rs7665090 risk variant on MS lesion pathology

MS lesion size (histology)

18 lesions (6 cases); protective 21 lesions (8 cases); risk

Lesion load (MRI)

35 MS patients; protective 40 MS patients; risk

Summary

NF-κB expression/ signaling chemokine secretion neurotoxic (A1) phenotype astrocyte/axon metabolic coupling lymphocyte recruitment lesion size lesion load

iPSC-derived astrocytes

SNP

tes

GWAS astrocytic phenotype lesion phenotype epigenetic studies astrocytic phenotype lesion load

change in susceptibility << astrocytic response (culture) < astrocyte response (lesion)

Outlook

iPSC-derived astrocytes

SNP

tes

GWAS astrocytic phenotype lesion phenotype epigenetic studies astrocytic phenotype lesion load

• 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
• f risk variant-regulated pathways

David Pitt Mayyan Mubarak Somiah Dahlawi Calvin Park Sarah Wang

Yale Neurology and Genetics

David Hafler Matt Lincoln Tomokazu Sumida Chris Cotsapas

Pitt Lab