Yasuaki Takagi
Yasuaki Takagi
Yasuaki Takagi
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Hard Tissue Research and Application in Aquatic Animals: <strong>Yasuaki</strong> <strong>Takagi</strong><br />
Hard Tissue Research and Application<br />
in Aquatic Animals<br />
<strong>Yasuaki</strong> TAKAGI<br />
Aquatic Animal Physiology Group<br />
Laboratory of Aquaculture Biology<br />
Division of Marine Life Science<br />
Faculty of Fisheries Sciences<br />
Hokkaido University<br />
Laboratory of Aquaculture Biology<br />
• Life science in aquatic animals<br />
Regulatory mechanisms of<br />
• Reproduction<br />
• Growth & Metabolism etc<br />
To promote development of "future"<br />
aquaculture and propagation systems<br />
• Reproductive Biology Group: ADACHI, TODO, IJIRI<br />
• Comparative Biochemistry Group: HARA, HIRAMATSU<br />
• Aquatic Animal Physiology Group: TAKAGI, URA<br />
Researches in<br />
Aquatic Animal Physiology Group<br />
Problems in Seafood Industry<br />
• Established to promote pearl aquaculture<br />
• Mechanism of pearl formation<br />
• Physiology of bivalves<br />
• Hard tissue physiology of aquatic animals<br />
• Mechanism of age-character formation<br />
• Application<br />
• Physiology of aquatic invertebrates<br />
Inedible parts<br />
50% Edible parts<br />
(Hard tissues) 50%<br />
Bones<br />
Exoskeleton<br />
Shells<br />
Scales<br />
Effective utilization<br />
Industrial<br />
waste<br />
Objective of Our Research<br />
High-value Added Seafood Industry<br />
Fish scale:<br />
a useful model to study corneal<br />
regeneration<br />
Bones<br />
Shells<br />
Applied Studies<br />
(effective utilization)<br />
Exoskeleton<br />
Scales<br />
Basic Studies<br />
(molecular mechanisms of<br />
hard tissue growth)
<strong>Yasuaki</strong> <strong>Takagi</strong><br />
Cornea<br />
Alignment of Collagen Fibrils in the Stroma<br />
Epithelium<br />
Stroma<br />
Endothelium<br />
Medical Treatment of Injured Cornea<br />
Fish Scales<br />
• No regeneration<br />
• Inactive fibroblasts<br />
• Treatment for injured cornea = implnntation<br />
• Eye-bank (donated) cornea, short in supply<br />
• High demand for the replacement material<br />
• Clear, thin, flexible but strong<br />
• 3-dimensionally aligned collagen fibers<br />
• Bio-inspired process<br />
• Unknown mechanism, hard to study<br />
Cornea-like Collagen in Fish Scales<br />
Fish Scale Has High Regenerating Ability<br />
Bony layer<br />
Bony-layer forming cell<br />
Basal plate (cornea-like collagen)<br />
Basal-plate forming cell
<strong>Yasuaki</strong> <strong>Takagi</strong><br />
When Scales Are Taken Off ・・・<br />
Process of Scale Regeneration<br />
Epidermis<br />
Dermis<br />
Muscle<br />
Scale<br />
Empty pocket<br />
Scale removal<br />
Formation of<br />
cellular clusters<br />
Deposition of<br />
scale matrix<br />
Regeneration<br />
Scale Regeneration<br />
• Differentiation of scale-forming cells<br />
from the stem cells<br />
Good model of cellular differentiation<br />
• Active synthesis of cornea-like collagen<br />
Good model of collagen-fibril alignment<br />
1. Cellular Mechanisms to Align Collagen Fibrils<br />
Collagen-binding protein<br />
that regulates alignment<br />
Diameter regulation<br />
Switching protein<br />
• Safe and reliable source of collagen<br />
2. Development of Scale Culture System<br />
in vivo<br />
Stem cells<br />
Epidermis<br />
Differentiation<br />
3. Seeking Fish Collagen with Higher<br />
Denaturation Temperature<br />
Collagen fibril<br />
(polymer of collagen molecule)<br />
Heating<br />
(denaturation)<br />
Gelatin<br />
Dermis<br />
Basal plate<br />
(Cornea-like collagen)<br />
Differentiation<br />
Collagen molecule<br />
Denaturation temperature<br />
• Mammals = 40ºC<br />
• Salmon < 20ºC<br />
In vitro synthesis of<br />
cornea-like collagen<br />
• Identification and isolation of stem<br />
cells<br />
• Clarification of cell environment<br />
• Identification of<br />
differentiation/activation factors<br />
• Higher denaturation temperature<br />
• Fish species<br />
• Different tissue source<br />
• Different aquaculture conditions
<strong>Yasuaki</strong> <strong>Takagi</strong><br />
Goal of This Project<br />
Fabrication of New Collagenous Matrix<br />
that Can Replace Function of Our Tissue<br />
from Fish Scale Collagen
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