Role of salt-induced kinase 1 in androgen neuroprotection against cerebral ischemia.
Androgens within physiological ranges protect castrated male mice from cerebral ischemic injury. Yet, underlying mechanisms are unclear. Here, we report that, after middle cerebral artery occlusion (MCAO), salt-induced kinase 1 (SIK1) was induced by a potent androgen-dihydrotestosterone (DHT) at protective doses. To investigate whether SIK1 contributes to DHT neuroprotection after cerebral ischemia, we constructed lentivirus-expressing small interference RNA (siRNA) against SIK1. The SIK1 knockdown by siRNA exacerbated oxygen-glucose deprivation (OGD)-induced cell death in primary cortical neurons, suggesting that SIK1 is an endogenous neuroprotective gene against cerebral ischemia. Furthermore, lentivirus-mediated SIK1 knockdown increased both cortical and striatal infarct sizes in castrated mice treated with a protective dose of DHT. Earlier studies show that SIK1 inhibits histone deacetylase (HDAC) activities by acting as a class IIa HDAC kinase. We observed that SIK1 knockdown decreased histone H3 acetylation in primary neurons. The SIK1 siRNA also exacerbated OGD-induced neuronal death in the presence of trichostatin A (TSA), an HDAC inhibitor, and decreased histone H3 acetylation at 4 hours reoxygenation in TSA-treated neurons. Finally, we showed that DHT at protective doses prevented ischemia-induced histone deacetylation after MCAO. Our finding suggests that SIK1 contributes to neuroprotection by androgens within physiological ranges by inhibiting histone deacetylation.
Cheng
Jian
J
Department of Anesthesiology and Peri-Operative Medicine, Portland, Oregon 97239-3098, USA. chengj@ohsu.edu
Uchida
Masayoshi
M
Zhang
Wenri
W
Grafe
Marjorie R
MR
Herson
Paco S
PS
Hurn
Patricia D
PD
D000728:Androgens / Q000494:pharmacology*; D000818:Animals; D015153:Blotting, Western; D002545:Brain Ischemia / Q000235:genetics* / Q000517:prevention & control*; D015687:Cell Hypoxia / Q000502:physiology; D002478:Cells, Cultured; D003342:Corpus Striatum / Q000502:physiology; D013196:Dihydrotestosterone / Q000494:pharmacology; D004790:Enzyme Induction / Q000187:drug effects; D005947:Glucose / Q000172:deficiency; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology; D007150:Immunohistochemistry; D020244:Infarction, Middle Cerebral Artery / Q000473:pathology; D016086:Lentivirus / Q000235:genetics; D008297:Male; D008845:Microinjections; D018696:Neuroprotective Agents; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis / Q000502:physiology*; D034741:RNA, Small Interfering / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020521:Stroke / Q000209:etiology / Q000473:pathology
D000728:Androgens; D056572:Histone Deacetylase Inhibitors; D018696:Neuroprotective Agents; D034741:RNA, Small Interfering; D013196:Dihydrotestosterone; D017346:Protein Serine-Threonine Kinases; C120299:Sik1 protein, rat; D005947:Glucose