Pregnane X receptor (PXR) activation: a mechanism for neuroprotection in a mouse model of Niemann-Pick C disease.
Niemann-Pick type C1 (NPC1) disease is a fatal neurodegenerative disease characterized by neuronal lipid storage and progressive Purkinje cell loss in the cerebellum. We investigated whether therapeutic approaches to bypass the cholesterol trafficking defect in NPC1 disease might delay disease progression in the npc1(-/-) mouse model. We show that the neurosteroid allopregnanolone (ALLO) and T0901317, a synthetic oxysterol ligand, act in concert to delay onset of neurological symptoms and prolong the lifespan of npc1(-/-) mice. ALLO and T0901317 therapy preserved Purkinje cells, suppressed cerebellar expression of microglial-associated genes and inflammatory mediators, and reduced infiltration of activated microglia in the cerebellar tissue. To establish whether the mechanism of neuroprotection in npc1(-/-) mice involves GABA(A) receptor activation, we compared treatment of natural ALLO and ent-ALLO, a stereoisomer that has identical physical properties of natural ALLO but is not a GABA(A) receptor agonist. ent-ALLO provided identical functional and survival benefits as natural ALLO in npc1(-/-) mice, strongly supporting a GABA(A) receptor-independent mechanism for ALLO action. On the other hand, the efficacy of ALLO, ent-ALLO, and T0901317 therapy correlated with the ability of these compounds to activate pregnane X receptor-dependent pathways in vivo. These findings suggest that treatment with pregnane X receptor ligands may be useful clinically in delaying the progressive neurodegeneration in human NPC disease.
Langmade
S Joshua
SJ
Center for Cardiovascular Research, Department of Internal Medicine, and Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, MO 63110, USA.
Gale
Sarah E
SE
Frolov
Andrey
A
Mohri
Ikuko
I
Suzuki
Kinuko
K
Mellon
Synthia H
SH
Walkley
Steven U
SU
Covey
Douglas F
DF
Schaffer
Jean E
JE
Ory
Daniel S
DS
D000818:Animals; D002531:Cerebellum / Q000187:drug effects / Q000378:metabolism; D004195:Disease Models, Animal; D058785:GABA-A Receptor Agonists; D015870:Gene Expression / Q000187:drug effects; D006845:Hydrocarbons, Fluorinated; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D018345:Mice, Knockout; D017628:Microglia / Q000187:drug effects; D009154:Mutation; D018696:Neuroprotective Agents / Q000627:therapeutic use*; D000077296:Niemann-Pick C1 Protein; D009542:Niemann-Pick Diseases / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D000077297:Pregnane X Receptor; D011280:Pregnanolone / Q000627:therapeutic use*; D011506:Proteins / Q000235:genetics; D011689:Purkinje Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D011987:Receptors, Steroid / Q000819:agonists*; D013237:Stereoisomerism; D013449:Sulfonamides / Q000627:therapeutic use*; D005466:Fluorocarbons; D000096926:Benzenesulfonamides
D058785:GABA-A Receptor Agonists; D006845:Hydrocarbons, Fluorinated; D047908:Intracellular Signaling Peptides and Proteins; D018696:Neuroprotective Agents; D000077296:Niemann-Pick C1 Protein; D000077297:Pregnane X Receptor; D011280:Pregnanolone; D011506:Proteins; D011987:Receptors, Steroid; D013449:Sulfonamides; C106831:Npc1 protein, mouse; C423915:T0901317; D005466:Fluorocarbons; D000096926:Benzenesulfonamides