決定的な血液形成は,AGM領域によって自律的に開始されます
1National Institute for Medical Research, London, United Kingdom.
Cell
|September 20, 1996
まとめ
造血幹細胞 (HSC) は哺乳類の血液発育に不可欠です. この研究は,大動脈-状腺-メソネフロス (AGM) 領域を,決定的なHSCの排他的な胚源として特定し,その起源を明確にします.
科学分野:
- 発達生物学 発達生物学とは
- ヘマトポエーシス (血液形成) とは
- 幹細胞の研究についてです.
背景:
- 胚形成過程における哺乳類の血球形成性幹細胞 (HSC) の起源と初期発達は,完全に理解されていません.
- 肝臓のコロニゼーション以前に,血球形成活動が卵黄袋と大動脈・状腺・メソネフロス (AGM) 領域で発生しますが,HSC生成におけるそれぞれの役割は議論されています.
研究 の 目的:
- 決定的な血液形成性幹細胞の胚の起源と初期生成の場所を決定する.
- 胚性造血性幹細胞のインビトロ拡張の可能性を調査する.
主な方法:
- 胚の組織を研究するために,新しい in vitro 臓器培養システムを採用しました.
- 妊娠10日目からの大動脈・胞・メソネフロス (AGM) 領域と卵黄袋のマウスの胚を培養した.
- これらの培養組織内の血液形成性幹細胞の生成と拡張が評価されました.
主要な成果:
- 造血幹細胞は,妊娠10日目に主動的に,そして,主として,大動脈-状腺-メソネフロス (AGM) 領域内で発症することが観察されました.
- 培養されたAGM領域内の血液形成性幹細胞の in vitro 拡張の証拠が得られた.
- 決定的なHSC生成に対する卵黄袋の貢献は,これらの発見によって支持されませんでした.
結論:
- 動脈-状腺-メソネフロス (AGM) 領域は,決定的な造血性幹細胞の主要な胚性源として特定されています.
- これらの発見は,AGM領域が肝臓の種を蒔き,最終的な成人の造血系を確立することを示しています.
- この研究は,哺乳類の造血系系の初期発達の起源について重要な洞察を提供している.
関連する概念動画
Lineage Commitment
Commitment is the process whereby stem cells:
Production of Formed Elements
Hemangioblasts are multipotent stem cells originating from the mesoderm. They give rise to hematopoietic stem cells (HSCs), which undergo hematopoiesis to produce all the formed elements of blood. This process is regulated by a complex network of hematopoietic growth factors, including transcription factors, growth factors, and cytokines. These factors stimulate the HSCs to divide and differentiate, though some HSCs remain undifferentiated to maintain a self-renewing pool.
Most HSCs commit to...
Most HSCs commit to...
Vascular Spasm
The vascular phase, also known as vasospasm, is the initial stage of hemostasis, crucial for preventing excessive bleeding when a blood vessel is injured. After a vessel is cut, nerves in the damaged area trigger pain and other sensory impulses. Simultaneously, the smooth muscles in the vessel wall contract, resulting in a vascular spasm. This contraction reduces the vessel's diameter at the injury site, slowing or stopping blood loss through the vessel wall. Vascular spasms typically last for...
Formation of the Platelet Plug
The platelet phase, the second stage of hemostasis, commences around 15-20 seconds after an injury. It follows and overlaps with the vascular phase, during which blood vessels constrict to minimize blood loss.
As the injured blood vessel contracts, endothelial cells undergo contraction, revealing collagen fibers in the basement membrane and underlying connective tissue. Furthermore, the plasma membrane of endothelial cells becomes adhesive, preparing the site for platelet adhesion. Platelets...
As the injured blood vessel contracts, endothelial cells undergo contraction, revealing collagen fibers in the basement membrane and underlying connective tissue. Furthermore, the plasma membrane of endothelial cells becomes adhesive, preparing the site for platelet adhesion. Platelets...
Autoregulation of Blood Flow
Autoregulation mechanisms are characterized by their inherent capacity for self-regulation without necessitating specific nervous stimulation or endocrine control. These mechanisms facilitate the adjustment of blood flow and, therefore, perfusion specific to each tissue region. This self-regulation encompasses chemical signals and myogenic controls.
Chemical Signaling in Autoregulation
Chemical signaling operates at the precapillary sphincter level, inciting either contraction or relaxation.
Chemical Signaling in Autoregulation
Chemical signaling operates at the precapillary sphincter level, inciting either contraction or relaxation.
Development of Blood Vessels
The development of the vascular system in a fetus is a complex and intricate process that begins as early as 15 to 16 days post-conception. This process starts outside the embryo, specifically in the mesoderm of the yolk sac, chorion, and connecting stalk. Approximately two days later, the formation of blood vessels occurs within the embryo itself.
The initial formation of this system is facilitated by the small amount of yolk present in the ovum and yolk sac. Blood vessels originate from...
The initial formation of this system is facilitated by the small amount of yolk present in the ovum and yolk sac. Blood vessels originate from...


