2020 Fiscal Year Research-status Report
Clarification of protective functions of Huntingtin-associated protein 1 against autonomic and motoneuron degeneration using genetically-engineered mice
| Project/Area Number |
20K16108
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| Research Institution | Yamaguchi University |
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Principal Investigator |
Md・Nabiul Islam 山口大学, 大学院医学系研究科, 助教 (80759671)
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| Project Period (FY) |
2020-04-01 – 2022-03-31
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| Keywords | Motor neuron / Autonomic neuron / Neurodegeneration / Distribution / Immmunohistochemistry |
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| Outline of Annual Research Achievements |
In our previous studies, we reported that Huntingtin-associated protein 1 (HAP1) can protect neurodegenerative apoptosis in vitro and HAP1 is abundantly expressed in the spinal autonomic neurons but completely lacking in motor neurons. These findings suggest that HAP1 might protect autonomic neurons, whereas due to lack of HAP1-protectivity, motoneurons are more vulnerable to neurodegeneration. In this research project, to clarify the in vivo effects of HAP1 on protection of autonomic/motoneurons, I examined the HAP1 expression in the brain stem and peripheral nervous system in adult mice. I clarified that similar to spinal motor neuron, brain stem motor neurons were also devoid of HAP1 protection.
In addition, the current study employing Western blot and immunohistochemistry is the first to determine the expression and distribution of HAP1 in the dorsal root ganglion (DRG) throughout the cervical to sacral regions in adult mouse. The present study is also the first to characterize HAP1 immunoreaction in relation to the sensory neuron subpopulations in the mouse DRG. The most striking data from a neuropathological viewpoint was that TH neurons in the DRG were devoid of HAP1-immunoreactivity. According to the STB/HAP1 protection hypothesis, lack of HAP1-immunoreactivity in the TH neurons might be interpreted as the light-touch sensitive DRG neurons being more vulnerable to certain stresses than other HAP1-ir sensory neurons. Now I am examining the ontogeny of the HAP1-expression in the mouse spinal cord of embryonic and neonatal stages, which is under progress.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
The purpose of this study is to clarify the in vivo protective effects of HAP1 against autonomic and motor neuron degeneration. To achieve the goal, I set out to examine the spatio-temporal expression of HAP1 in the autonomic and motor neurons of spinal cord, in brain stem as well as in enteric neurons. Then I aimed to investigate the changes in developmental pattern and number of autonomic neurons between Wild type and HAP1-KO mice that is produced at our laboratory using CRISPR-Cas9 technology. I have completed the examination of spatio-temporal expression of HAP1 in the autonomic and motor neurons of spinal cord, brain stem and peripheral nervous system of rodents.
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| Strategy for Future Research Activity |
To answer the question, whether the plausible HAP1 protection against in vivo motoneuron degeneration is stage dependent or not, a complete profile of the HAP1-expression in the brain stem or spinal motor neurons of embryonic (ED15, ED 17, ED19), neonatal (day1, day 7), adult (10w), and aged (80w) mice of both sexes will be obtained using immunohistochemistry. Finally, to examine the protective functions of HAP1 from against neurodegeneration in vivo, we have generated motor neuron specific HAP1-transgenic (TG) mice. To clarify the protective functions of HAP1, I will perform a motor function-related behavioral test battery comparison between aged-wild type and aged-HAP1-TG mice, which includes locomotor activity test, hang test, paw print analysis, rotarod and grip strength test. I have also a plan to examine the HAP1 immunoreaction and its protective function in enteric nervous system. I will also compare the the changes of autonomic neurons and their functions using our recently generated HAP1-KO mice.
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| Causes of Carryover |
Due to COVID-19 pandemic situation all the academic conferences/meetings were cancelled (in person presentation), hence no money was spent for travel purposes.
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