歯の再生の望み
Hello everyone, SCIENSPOT is a podcast that shines a spotlight on the latest scientific
technology from Japan. Your host is REN from SCIEN-TALK.
So today's topic is a tooth. Losing a tooth can be tough, right? Whether it's from cavities,
gum disease, or an accident, current solutions like dentures, bridges, or implants are functional.
But they're still not quite like having your natural teeth.
The dream of regenerating an entire tooth is a major research goal worldwide. Scientists
are making progress in growing tooth germs in labs and transplanting them.
However, there's a big challenge. We don't yet have sufficient technology to precisely
control the shape, especially the length and structure of the regenerated tooth roots.
The tooth root is incredibly important. It anchors the tooth firmly in the jawbone and
supports the immense forces of chewing. It also contains the apical foramen, a small
opening for nerves and blood vessels, essentially the tooth's lifeline.
Without a properly formed root, a regenerated tooth won't be stable or fully functional.
エピジェネティクスの発見
Past efforts have included using 3D scaffolds to guide the shape and directly manipulating
gene expression in tooth-forming cells. And about a more fundamental and precise method
for root control was needed. That brings us to today's exciting news,
discovered by a joint research group from Tohoku University in Japan and Mayo Clinic in the U.S.
They've found the epigenetics, a mechanism that adjusts gene function without changing the DNA
sequence, control classification in dentin and cementum, and thus tooth root formation.
Let's quickly define epigenetics. Imagine DNA as a vast recipe book. Epigenetics doesn't change
the recipes themselves, it means the DNA sequence, but rather determines which recipes are used or
how often. It's like putting sticky notes on certain recipe pages to highlight them or closing
others to indicate they're not needed right now. This on or off switch for genes is crucial
for cell differentiation and function. Central to this research is a specific enzyme involved
in epigenetics, histone deacetylase, or HDAC. What is HDAC? HDAC are enzymes that remove
acetyl group from histones, which are proteins around which DNA is wound, and think of DNA as a
long thread and histones as spools. When DNA is tightly wound around these spools, it's harder for
the cell to read to genes on that section of DNA, effectively turning them off. HDACs make the DNA
wind more tightly. In this study, HDAC3 was the specific enzyme of interest. The research team
led by Dr. Nibe and Prof. Egusa from Tohoku University and Prof. Jennifer
from Mayo Clinic focused on HDAC3's role. They created genetically modified mice called
She-KO mice, where HDAC3 was absent in cells expressing ostrich. Ostrich is a gene crucial
for bone, dentin, and cementum formation. Then they analyzed the teeth of these mice.
The results were remarkable. Compared to wild-type mice, the knockout mouse exhibited
significantly shorter molar roots. Additionally, the apical foramen, the hole at the roof tip
HDAC3と歯の根の成長
for nerves and blood vessels, closed prematurely in these mice. This strongly suggests that HDAC3
is essential for proper tooth root growth and maintaining openness of the apical foramen.
The researchers also performed cell-level experiments. They treated cement blast cells
that form cementum on the root surface with HDAC3 inhibitor drug. They found that
this treatment suppressed the expression of calcification-related genes and inhibited
actual calcification by the cement blast. This directly demonstrates HDAC3's involvement
in the calcification process of cementum, a hard tissue of the tooth.
These experiments provide clear scientific evidence that HDAC3, through epigenetic
mechanisms for controls, critical processes determining tooth root morphology, including
root length, apical foramen formation, and cementum calcification.
This research offers an immense hope for future tooth regeneration therapies. It opens up new
possibilities for controlling the morphology of regenerated tooth roots using epigenetics.
再生歯科の未来
By precisely adjusting HDAC3 activity, perhaps with medication, we could potentially control
the length of regenerated tooth roots, preventing them from overgrowing and guiding them to form
their ideal shape. This is a huge step toward making regenerative dentistry a reality.
That's all for today's SciencePod. I'd love for you to listen to the podcast and
post your notes and thoughts with the hashtag SciencePod. Thank you for listening and see you next time.
