Mechanisms and principles of branch pattern formation of dendrites

Dendrite morphologies of CNS neurons are highly diverse, depending on cell type and function. The architecture of dendritic arbors critically affects the integration of neuronal inputs and propagation of chemical signals, and hence determines the connectivity of neurons. The question of how neurons acquire their appropriate morphology is a major issue in the study of neuronal development. In spite of the increasing number of molecular signals that have been identified as regulators of dendritic arborization patterns, the precise function of each molecule in the specific steps of branch dynamics largely remains elusive. Cerebellar Purkinje cells develop intricate dendritic arbors with minimal branch overlap. We developed a method of long-term time-lapse observation of dendritic branch dynamics in growing Purkinje cells in culture. Using a combinatorial approach with quantitative image analyses and computer-aided simulation, we identified the fundamental rules of growth dynamics that govern the construction of the characteristic dendritic patterns in Purkinje cells(Fujishima et al. 2012). We also demonstrated that a small change in actin dynamics led to a siginifant difference in dendrite growth dynamics and the untimate branch pattern in a mature neuron (Kawabata Galbraith et al., 2018). Purkinje cells arborize fan-shaped dendrites which form perpendicular contacts with the afferent granule cell axons. We developed a new culture system to reconstitute the axon-dendrite wiring topology. Using this, we identified molecular players involved in the perpendicular connectivity (Fujishima et al., 2020).

Time-lapse observation and computer-assisted simulation of dendrite formation in cultured Purkinje cells


長期タイムラプス観察により樹状突起形成過程を解析し、必要最小限のパラメータを抽出して モデル細胞を再構築した。

We have successfully visualized the dynamic motility of organelles, including the nucleus, centrosomes, mitochondria and Golgi apparatus, in developing neurons. We are investigating how the neural activity during circuit formation affects dendrite arborization.

Super-resolution images of mitochondria dynamics in cultured hippocampus neuron


培養した海馬ニューロンの細胞質(緑)とミトコンドリア(マゼンダ、白)の動態を超解像顕微鏡(Zeiss Airy scan)を用いて観察した。



 我々は中枢神経系ニューロンの中でも際立って緻密な樹状突起を形成する小脳プルキンエ細胞を用い、分散培養下で樹状突起発達過程を1週間以上連続観察する系を確立し、樹状突起ダイナミクスの定量的解析と数理解析を用いてその形成原理を明らかにしました(Fujishima et al. 2012)。また、分化中の細胞骨格アクチン動態のわずかなズレが樹状突起ダイナミクスに影響し、成熟したニューロンの分岐の形を大きく変えてしまうことを証明しました(Kawabata Galbraith et al. 2018詳細はこちら)。 プルキンエ細胞は脳内で入力する顆粒細胞軸索と直交する扇型の樹状突起を展開します。神経回路トポロジーを解析する新たな培養再構成系を開発し、プルキンエ細胞樹状突起が顆粒細胞軸索に対し垂直方向に伸展することを観察し、その分子機構の一端を明らかにしました(Fujishima 2020)。発達中の樹状突起内でゴルジ体、ミトコンドリアなどのオルガネラの動態を可視化することにも成功しています。現在、神経活動が樹状突起発達に与える影響とその分子機構を解析しています。


Fujishima K, Kurisu J, Yamada M, Kengaku M. (2020) βIII spectrin controls the planarity of Purkinje cell dendrites by modulating perpendicular axon-dendrite interactions. Development 147(24):dev194530.

Kawabata-Galbraith, K., Fujishima, K., Mizuno, H., Lee, S.J., Uemura, T., Sakimura, K., Mishina, M., Watanabe, N.  and Kengaku, M. (2018) MTSS1 regulation of actin-nucleating formin DAAM1 in dendritic filopodia determines final dendritic configuration of Purkinje cells. Cell Rep. 24(1):95-106.

Hatsukano, T., Kurisu, J., Fukumitsu, K., Fujishima, K. and Kengaku, M. (2017) Thyroid hormone induces PGC-1 α during dendritic outgrowth in mouse cerebellar Purkinje cells. Front Cell Neurosci. 11:133

Fukumitsu, K., Hatsukano, T., Yoshimura, A., Heuser, J., Fujishima, K. and Kengaku, M. (2016) Mitochondrial fission protein Drp1 regulates mitochondrial transport and dendritic arborization in cerebellar Purkinje cells. Mol Cell Neurosci.71:56-65

Fukumitsu, K., Fujishima, K., Yoshimura, A., Wu, Y.K., Heuser, J. and Kengaku, M. (2015) Synergistic action of dendritic mitochondria and creatine kinase maintains ATP homeostasis and actin dynamics in growing neuronal dendrites. J. Neurosci. 35(14):5707- 5723.

Wu, Y.K., Fujishima, K. and Kengaku, M. (2015) Differentiation of Apical and Basal Dendrites in Pyramidal Cells and Granule Cells in Dissociated Hippocampal Cultures. PLoS ONE 10(2) e0118482.

Fujishima, K., Horie, R., Mochizuki, A. and Kengaku M. (2012) Principles of branch dynamics governing shape characteristics of cerebellar Purkinje cell dendrites. Development 139: 3442-3455.