〒162-8666 8-1, Kawada-cho, Shinjuku-ku, Tokyo
Our main research focus is the molecular mechanisms regulating cell proliferation and differentiation during retinal development and regeneration. We also study on the neural circuitry in hippocampal and parahippocampal areas of the brain, the development of the human skull and the mechanism of arterial calcification during osteoporosis. As we teach gross anatomy to medical students, the gross anatomy course including lectures and cadaver dissection is also offered if requested.
(1)Mechanisms regulating the proliferation and differentiation of retinal
cells during development The retina is a part of the central nervous system
consisting of 6 types of neurons and 1 type of glia (Müller glia). During
development, retinal progenitor cells increase their number by proliferation,
but eventually exit the cell cycle and differentiate into specific cell
types. Molecular mechanisms regulating this process are only partially
understood. We study the role of cell cycle regulators, transcription factors,
and epigenetic factors in the developing rodent retina using histological
and molecular biological techniques.
(2)Retinal neuronal regeneration by Müller glia In lower vertebrates like fish, Müller glia dedifferentiate to retinal progenitors, proliferate and redifferentiate to neurons when the retina is damaged. However, such regenerative capacity of Müller glia in mammals is very limited. We are investigating the mechanisms that limit the regenerative potential of Müller glia and exploring the strategy to repair damaged retina by activating the endogenous regenerative potential of the mammalian retina.
(3)Morphological analysis of memory circuits in the mammalian species. It is predicted that the most essential portion of the memory circuit is generally preserved from rodents to primates. To elucidate such fundamental connections, we invesigate neuronal connections between the hippocampus and parahippocampal cortices (i.e., the presubiculum, parasubiculum, and entorhinal cortex) in several mammalian species including the rats, rabbits and marmosets. Standard tracers, such as HRP, CTB, and BDA, are injected into the hippocampal body or several parahippocampal cortices, which allows investigation of the input-and-output connections between these areas on the cell mass level. We also use the palGFP-expressing Sindbis virus vector to analyze axonal arborizations and terminations of single neurons.
(4)Morphological analysis of the commissural entorhino-dentate fibers following unilateral entorhinal lesion. It is known that, following unilateral lesion of the entorhinal cortex of the adult rat, the denervated granule cells of the dentate gyrus are reinnervated as a result of the growth of the pathway from the surviving contralateral entorhinal cortex. To investigate the morphological features of sprouted commissural entorhino-dentate fibers from single entorhinal neurons, we use the palGFP-expressing Sindbis virus vector as the anterograde tracer. The vector is useful for tracing long and highly arborized axonal branches and it is possible to detect some unknown morphological changes in the reinnervated fibers. Our study may contribute to understanding the mechanisms of spontaneous recovery from memory impairment, which is caused by degeneration of the entorhinal cortex.
Hiroki Fujieda Yoshiko Honda Toru Hayakawa Fuminori Saitoh Kaori Nomura-Komoike
8-1, Kawada-cho, Shinjuku-ku, Tokyo