Establishment of intravital imaging of the lacrimal gland for elucidation of mechanism of lacrimation

• Project/Area Number: 17K16983
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Ophthalmology
• Research Institution: Keio University
• Principal Investigator: IMADA Toshihiro 慶應義塾大学, 医学部(信濃町), 特任助教 (80790360)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2019: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2018: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2017: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
• Keywords: 生体イメージング / 二光子顕微鏡 / 涙液 / 涙腺 / カルシウムシグナル / 薬理遺伝学 / 泣く / 生体カルシウムイメージング / 涙 / 眼科学

Outline of Final Research Achievements

We established an intravital imaging system enable to visualize and analyze the Ca2+ response in the lacrimal gland (LG) by combination of two-photon microscopy with transgenic mice expressing the genetically encoded Ca2+ indicator, yellow cameleon (YC) 3.6 or YC-Nano15. In this system, a perfusion chamber is fitted surrounding the LG to allow for exposure of stimulants and inhibitors only to the LG. We analyzed tear secretion and Ca2+ responses in the LG myoepithelial cells and acinar cells during the corneal sensory stimulation. We also succeeded in visualizing Ca2+ response in the LG acinar cells during pharmacogenetic excitation of superior salivatory nucleus which is important brain region controlling lacrimation.

Academic Significance and Societal Importance of the Research Achievements

従来の涙液分泌に関する研究では、涙腺機能に主眼が置かれ、脳との連動性に着目されずに解析されてきた。本研究では、二光子顕微鏡による深部生体イメージング、涙腺細胞腫特異的カルシウムプローブを発現する遺伝子改変マウス、薬理遺伝学による脳操作を組み合わせることで、脳―涙腺活動の直接的な関わりを解析可能とする実験系を構築した。本研究を元に、脳―涙腺活動の連動により生じる「泣く」メカニズムを解明することにより、根本治療法が存在しない眼表面疾患に対し、新しい、創薬・治療戦略の確立が可能となる。

Research Products

• [Journal Article] Identification of Lacrimal Gland Postganglionic Innervation and Its Regulation of Tear Secretion. (2020)
  • Author(s): Kai Jin, Toshihiro Imada, Ryuji Hisamura, Masataka Ito, Haruki Toriumi, Kenji F Tanaka, Shigeru Nakamura ＆ Kazuo Tsubota
  • Journal Title: The American Journal of Pathology Volume: 190 Issue: 5 Pages: 1068-1079
  • DOI: 10.1016/j.ajpath.2020.01.007
  • Peer Reviewed / Open Access
• [Journal Article] Corneal Sensory Experience via Transient Receptor Potential Vanilloid 1 Accelerates the Maturation of Neonatal Tearing (2019)
  • Author(s): Jin Kai、Imada Toshihiro、Nakamura Shigeru、Izuta Yusuke、Oonishi Erina、Shibuya Michiko、Sakaguchi Hisayo、Tanabe Hirotaka、Ito Masataka、Katanosaka Kimiaki、Tsubota Kazuo
  • Journal Title: The American Journal of Pathology Volume: 189 Issue: 9 Pages: 1699-1710
  • DOI: 10.1016/j.ajpath.2019.05.015
  • Peer Reviewed / Open Access
• [Journal Article] Intravital Two-photon Imaging of Ca2+ signaling in Secretory Organs of Yellow Cameleon Transgenic Mice (2018)
  • Author(s): Kai Jin, Toshihiro Imada, Shigeru Nakamura, Yusuke Izuta, Erina Oonishi, Michiko Shibuya, Hisayo Sakaguchi, Takahiro Adachi & Kazuo Tsubota
  • Journal Title: Scientific Reports Volume: 8 Issue: 1
  • DOI: 10.1038/s41598-018-34347-1
  • Peer Reviewed / Open Access
• [Presentation] In vivo dynamics of Ca2+-dependent myoepithelial contraction in lacrimal gland (2017)
  • Author(s): Toshihiro Imada, Kai Jin, Yusuke Izuta, Shigeru Nakamura, Takahiro Adachi, Kazuo Tsubota
  • Organizer: The Annual Meeting of Association for Research in Vision and Ophthalmology 2017 (ARVO2017)
  • Int'l Joint Research
• [Presentation] Kai Jin, Toshihiro Imada, Yusuke Izuta, Shigeru Nakamura, Kazuo Tsubota (2017)
  • Author(s): Lacrimal Gland Squeezing by Contraction of Myoepithelial Cell Affects Tear Secretion
  • Organizer: The Annual Meeting of Association for Research in Vision and Ophthalmology 2017 (ARVO2017)
  • Int'l Joint Research