Department of Biology, Duke University, Durham, NC, 27708, USA.
Department of Biology, Duke University, Durham, NC, 27708, USA.
Dev Biol. 2022 Nov;491:56-65. doi: 10.1016/j.ydbio.2022.08.005. Epub 2022 Sep 5.
Sea urchin larvae spend weeks to months feeding on plankton prior to metamorphosis. When handled in the laboratory they are easily injured, suggesting that in the plankton they are injured with some frequency. Fortunately, larval wounds are repaired through an efficient wound response with mesenchymal pigment cells and blastocoelar cells assisting as the epithelium closes. An injury to the epithelium leads to an immediate calcium transient that rapidly spreads around the entire larva and is necessary for activating pigment cell migration toward the wound. If calcium transport is blocked, the pigment cells fail to activate and remain in place. When activated, pigment cells initiate directed migration to the wound site from distances of at least 85 μm. Upon arrival at the wound site they participate in an innate immune response. Blastocoelar cells are recruited to the injury site as well, though the calcium transient is unnecessary for activating these cells. At the wound site, blastocoelar cells participate in several functions including remodeling the skeleton if it protrudes through the epithelium.
海胆幼虫在变态之前要花数周甚至数月的时间以浮游生物为食。在实验室中处理它们时，它们很容易受伤，这表明在浮游生物中它们会经常受伤。幸运的是，幼虫的伤口通过一种有效的伤口反应来修复，间充质色素细胞和囊胚腔细胞协助上皮细胞闭合。上皮细胞受伤会立即引起钙瞬变，钙瞬变迅速扩散到整个幼虫身上，对于激活色素细胞向伤口迁移是必要的。如果钙转运被阻断，色素细胞就无法激活，仍留在原处。当被激活时，色素细胞会从至少 85μm 的距离开始向伤口部位定向迁移。到达伤口部位后，它们会参与先天免疫反应。囊胚腔细胞也被招募到损伤部位，但钙瞬变对于激活这些细胞是不必要的。在伤口部位，囊胚腔细胞参与几个功能，包括修复如果突出穿过上皮的骨骼。
