Cholestenoic acids regulate motor neuron survival via liver X receptors
Spyridon Theofilopoulos, … , Ernest Arenas, Yuqin Wang
Spyridon Theofilopoulos, … , Ernest Arenas, Yuqin Wang
Published November 3, 2014; First published October 1, 2014
Citation Information: J Clin Invest. 2014;124(11):4829-4842. https://doi.org/10.1172/JCI68506.
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Categories: Research Article Neuroscience

Cholestenoic acids regulate motor neuron survival via liver X receptors

Abstract

Cholestenoic acids are formed as intermediates in metabolism of cholesterol to bile acids, and the biosynthetic enzymes that generate cholestenoic acids are expressed in the mammalian CNS. Here, we evaluated the cholestenoic acid profile of mammalian cerebrospinal fluid (CSF) and determined that specific cholestenoic acids activate the liver X receptors (LXRs), enhance islet-1 expression in zebrafish, and increase the number of oculomotor neurons in the developing mouse in vitro and in vivo. While 3β,7α-dihydroxycholest-5-en-26-oic acid (3β,7α-diHCA) promoted motor neuron survival in an LXR-dependent manner, 3β-hydroxy-7-oxocholest-5-en-26-oic acid (3βH,7O-CA) promoted maturation of precursors into islet-1+ cells. Unlike 3β,7α-diHCA and 3βH,7O-CA, 3β-hydroxycholest-5-en-26-oic acid (3β-HCA) caused motor neuron cell loss in mice. Mutations in CYP7B1 or CYP27A1, which encode enzymes involved in cholestenoic acid metabolism, result in different neurological diseases, hereditary spastic paresis type 5 (SPG5) and cerebrotendinous xanthomatosis (CTX), respectively. SPG5 is characterized by spastic paresis, and similar symptoms may occur in CTX. Analysis of CSF and plasma from patients with SPG5 revealed an excess of the toxic LXR ligand, 3β-HCA, while patients with CTX and SPG5 exhibited low levels of the survival-promoting LXR ligand 3β,7α-diHCA. Moreover, 3β,7α-diHCA prevented the loss of motor neurons induced by 3β-HCA in the developing mouse midbrain in vivo.Our results indicate that specific cholestenoic acids selectively work on motor neurons, via LXR, to regulate the balance between survival and death.

Authors

Spyridon Theofilopoulos, William J. Griffiths, Peter J. Crick, Shanzheng Yang, Anna Meljon, Michael Ogundare, Satish Srinivas Kitambi, Andrew Lockhart, Karin Tuschl, Peter T. Clayton, Andrew A. Morris, Adelaida Martinez, M. Ashwin Reddy, Andrea Martinuzzi, Maria T. Bassi, Akira Honda, Tatsuki Mizuochi, Akihiko Kimura, Hiroshi Nittono, Giuseppe De Michele, Rosa Carbone, Chiara Criscuolo, Joyce L. Yau, Jonathan R. Seckl, Rebecca Schüle, Ludger Schöls, Andreas W. Sailer, Jens Kuhle, Matthew J. Fraidakis, Jan-Åke Gustafsson, Knut R. Steffensen, Ingemar Björkhem, Patrik Ernfors, Jan Sjövall, Ernest Arenas, Yuqin Wang

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Figure 2

Analysis of the nuclear receptor activational capacity of oxysterols and cholestenoic acids.

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Analysis of the nuclear receptor activational capacity of oxysterols and...
(A) Luciferase activity in SN4741 neural cells transfected with an LXR-responsive luciferase reporter construct (LXRE) with or without LXRα and stimulated for 24 hours with 22R-HC (10 μM), a known LXRα ligand (3, 4), or the compounds indicated. (B) Similar assay in cells transfected with an FXR-responsive luciferase reporter construct (FXRE) with or without FXR and stimulated for 24 hours with CDCA, a known FXR ligand, or the compounds indicated. (C) Additional luciferase assays performed as in A with or without addition of the LXR antagonist GGPP (10 μM) along with the indicated cholesterol metabolites (10 μM each). Values in A–C are fold activation over the basal LXRE or FXRE luciferase activity (set to 1) (n = 3). *P < 0.05, **P < 0.01 vs. vehicle or as indicated by brackets, Mann-Whitney test. (D) TR-FRET LXRβ coactivator assay, used to determine the binding affinity of cholestenoic acids as well as the known LXR ligands GW3965 and 24,25-EC toward the LXRβ-LBD (n = 3). The 520:495 TR-FRET ratio was determined as described in Methods. *P < 0.05 vs. vehicle for ≥10 μM 3β,7α-diHCA, ≥10 μM 3β,7β-diHCA, ≥10 μM 3β-HCA, ≥5 μM 24,25-EC, and ≥5 μM GW3965, Mann-Whitney test. (E) 3β,7α-diHCA, 3β,7β-diHCA and 3β-HCA induced significant increases in Abca1, Abcg1, and Srebf1 in SN4741 cells (n = 3). *P < 0.05, **P < 0.01 vs. vehicle, Mann-Whitney test.