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Altered Behavioral Performance in the Neuron-Specific HIF-1- and HIF-2-Deficient Mice Following Chronic Hypoxic Exposure. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1269:271-276. [PMID: 33966229 DOI: 10.1007/978-3-030-48238-1_43] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Hypoxia-inducible factors (HIFs) are transcriptional regulators that mediate in mice for HIF-1 and HIF-2. The objective of this study was to investigate the effect of neuronal deletion of HIF-1 and HIF-2 in hypoxic adaptation by using the neuron-specific knockout (KO) mice. The floxed control and KO mice were used. Hypoxic mice were kept in a hypobaric chamber at a pressure of 300 torr (0.4 ATM, which was equivalent to 8% oxygen under normobaric condition) for 3 weeks. The littermate, normoxic control mice were housed in the same room next to the chamber to match ambient conditions. Body weights were monitored throughout the 3-week course. Cognitive function was measured using a Y-maze test; motor functions were measured using the rotarod test and the grip strength test. The hematocrit increased significantly at the end of 3-week hypoxic exposure in both control and KO mice. In the Y-maze test, the alternation rate (indicative of sustained cognition) trended lower in the KO mice compared to the controls following hypoxia (%, 51.3 ± 13.1, n = 6 vs. 63.2 ± 12.0, n = 8). In the rotarod test, the latency (seconds) in the KO mice was significantly lower compared to the controls (50.4 ± 5.7 vs. 77.1 ± 5.0, n = 3 each before hypoxia and 66.4 ± 3.4, n = 6 vs. 98.1 ± 15.4 after hypoxia, n = 3). The grip strength in the KO mice was similar compared to the control mice before hypoxia, but the strength of KO mice trended higher after hypoxic exposure. Our data suggest that deficiency of neuronal HIF-1 and HIF-2 may result in changes in behavioral performance and other adaptative responses to hypoxia.
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Kanno I, Seki C, Takuwa H, Jin ZH, Boturyn D, Dumy P, Furukawa T, Saga T, Ito H, Masamoto K. Positron emission tomography of cerebral angiogenesis and TSPO expression in a mouse model of chronic hypoxia. J Cereb Blood Flow Metab 2018; 38:687-696. [PMID: 28128020 PMCID: PMC5888851 DOI: 10.1177/0271678x16689800] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The present study aimed to examine whether positron emission tomography (PET) could evaluate cerebral angiogenesis. Mice were housed in a hypoxic chamber with 8-9% oxygen for 4, 7, and 14 days, and the angiogenic responses were evaluated with a radiotracer, 64Cu-cyclam-RAFT-c(-RGDfK-)4, which targeted αVβ3 integrin and was imaged with PET. The PET imaging results showed little uptake during all of the hypoxic periods. Immunofluorescence staining of the β3 integrin, CD61, revealed weak expression, while the microvessel density assessed by CD31 staining increased with the hypoxic duration. These observations suggest that the increased vascular density originated from other types of vascular remodeling, unlike angiogenic sprouting. We then searched for any signs of vascular remodeling that could be detected using PET. PET imaging of 11C-PK11195, a marker of the 18-kDa translocator protein (TSPO), revealed a transient increase at day 4 of hypoxia. Because the immunofluorescence of glial markers showed unchanged staining over the early phase of hypoxia, the observed upregulation of TSPO expression probably originated from non-glial cells (e.g. vascular cells). In conclusion, a transient increase in TSPO probe uptake was detected with PET at only the early phase of hypoxia, which indicates an early sign of vascular remodeling induced by hypoxia.
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Affiliation(s)
- Iwao Kanno
- 1 Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Chie Seki
- 1 Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Hiroyuki Takuwa
- 1 Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Zhao-Hui Jin
- 1 Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Didier Boturyn
- 2 Département de Chimie Moléculaire, Université Grenoble Alpes, Grenoble, France
| | - Pascal Dumy
- 3 Institut des Biomolécules Max Mousseron, École Nationale Supérieure de Chimie de Montpellier, Montpellier, France
| | - Takako Furukawa
- 1 Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Tsuneo Saga
- 1 Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Hiroshi Ito
- 1 Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Kazuto Masamoto
- 1 Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan.,4 Brain Science Inspired Life Support Research Center, University of Electro-Communications, Tokyo, Japan
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