Sodium phenylbutyrate prolongs survival and regulates expression of anti-apoptotic genes in transgenic amyotrophic lateral sclerosis mice.
Multiple molecular defects trigger cell death in amyotrophic lateral sclerosis (ALS). Among these, altered transcriptional activity may perturb many cellular functions, leading to a cascade of secondary pathological effects. We showed that pharmacological treatment, using the histone deacetylase inhibitor sodium phenylbutyrate, significantly extended survival and improved both the clinical and neuropathological phenotypes in G93A transgenic ALS mice. Phenylbutyrate administration ameliorated histone hypoacetylation observed in G93A mice and induced expression of nuclear factor-kappaB (NF-kappaB) p50, the phosphorylated inhibitory subunit of NF-kappaB (pIkappaB) and beta cell lymphoma 2 (bcl-2), but reduced cytochrome c and caspase expression. Curcumin, an NF-kappaB inhibitor, and mutation of the NF-kappaB responsive element in the bcl-2 promoter, blocked butyrate-induced bcl-2 promoter activity. We provide evidence that the pharmacological induction of NF-kappaB-dependent transcription and bcl-2 gene expression is neuroprotective in ALS mice by inhibiting programmed cell death. Phenylbutyrate acts to phosphorylate IkappaB, translocating NF-kappaB p50 to the nucleus, or to directly acetylate NF-kappaB p50. NF-kappaB p50 transactivates bcl-2 gene expression. Up-regulated bcl-2 blocks cytochrome c release and subsequent caspase activation, slowing motor neuron death. These transcriptional and post-translational pathways ultimately promote motor neuron survival and ameliorate disease progression in ALS mice. Phenylbutyrate may therefore provide a novel therapeutic approach for the treatment of patients with ALS.
Ryu
Hoon
H
Geriatric Research Education and Clinical Center, Bedford VA Medical Center, Bedford, Massachusetts, USA.
Smith
Karen
K
Camelo
Sandra I
SI
Carreras
Isabel
I
Lee
Junghee
J
Iglesias
Antonio H
AH
Dangond
Fernando
F
Cormier
Kerry A
KA
Cudkowicz
Merit E
ME
Brown
Robert H
RH
Ferrante
Robert J
RJ
D000107:Acetylation / Q000187:drug effects; D000690:Amyotrophic Lateral Sclerosis / Q000235:genetics / Q000401:mortality / Q000473:pathology / Q000503:physiopathology*; D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D061945:Caspase Inhibitors; D002470:Cell Survival / Q000187:drug effects; D003474:Curcumin / Q000494:pharmacology; D045304:Cytochromes c / Q000037:antagonists & inhibitors; D018450:Disease Progression; D015870:Gene Expression / Q000187:drug effects*; D006657:Histones / Q000378:metabolism; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009046:Motor Neurons / Q000187:drug effects; D016328:NF-kappa B / Q000378:metabolism; D052002:NF-kappa B p50 Subunit; D010654:Phenylbutyrates / Q000494:pharmacology*; D011401:Promoter Regions, Genetic / Q000187:drug effects; D011498:Protein Precursors / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D013116:Spinal Cord / Q000187:drug effects / Q000378:metabolism / Q000473:pathology
D061945:Caspase Inhibitors; D006657:Histones; D016328:NF-kappa B; D052002:NF-kappa B p50 Subunit; D010654:Phenylbutyrates; D011498:Protein Precursors; D019253:Proto-Oncogene Proteins c-bcl-2; D045304:Cytochromes c; D003474:Curcumin