Decreased vulnerability of hippocampal neurons after neonatal hypoxia-ischemia in bis-deficient mice.
The Bcl-2-interacting death suppressor (Bis) protein is involved in antiapoptosis and antistress pathways. However, its roles after neonatal hypoxia-ischemia remain obscure. Therefore, we investigated the effects of Bis deletion on hippocampal cell death following neonatal hypoxia-ischemia. We transected the right common carotid artery of bis(+/+) and bis(-/-) mice at postnatal Day 7 and subjected them to hypoxia for 35 min. Cresyl violet staining showed that hypoxia-ischemia induced progressive cell death in the hippocampi of bis(+/+) mice. Moreover, Bis was expressed in astrocytes, not microglia, in sham-manipulated hippocampi of bis(+/+) mice, and was markedly enhanced after hypoxia-ischemia. Immunoblotting showed that Bis expression significantly increased 3 and 7 days following hypoxia-ischemia. Unexpectedly, 7 days after hypoxia-ischemia, the number of hippocampal NeuN-positive cells was higher in the bis(-/-) mice than in the bis(+/+) mice. We subsequently performed transcriptomic analysis and quantitative real time polymerase chain reaction to search for the underlying genes responsible for resistance to hypoxia-ischemia in the bis(-/-) hippocampus. These studies showed that 6 h after hypoxia-ischemia, galectin 3 and filamin C levels increased to a lesser extent in the bis(-/-) hippocampi compared with the bis(+/+) hippocampi. Finally, our in vitro hypoxia-ischemia model, using A172 glioma cells and primary astrocytes, showed that downregulation of Bis blocked the enhanced expression of galectin 3 after oxygen-glucose deprivation. This study demonstrated that Bis was upregulated in the astrocytes after hypoxia-ischemia. In addition, we showed that hippocampal neurons are less vulnerable to hypoxia-ischemia in mice lacking Bis, possibly because of the modulation of galectin 3 induction.
Department of Pharmacology, Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea.
Kyung-Ok
KO
Cho
Kyung-Eon
KE
Lee
Dong-Ye
DY
Youn
Kyoung Hoon
KH
Jeong
Joo Youn
JY
Kim
Hye Hyeon
HH
Yoon
Jeong-Hwa
JH
Lee
Seong Yun
SY
Kim
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D000831:Animals, Newborn; D051017:Apoptosis Regulatory Proteins; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D045744:Cell Line, Tumor; D015536:Down-Regulation / Q000235:genetics*; D006624:Hippocampus / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D020925:Hypoxia-Ischemia, Brain / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009474:Neurons / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley
D048868:Adaptor Proteins, Signal Transducing; D051017:Apoptosis Regulatory Proteins; C498806:Bag3 protein, mouse; D002352:Carrier Proteins