Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Department of Orthodontics, School & Hospital of Stomatology, Shanghai, China.
Tongji University School of Life Sciences and Technology, Department of Molecular and Cell Biology, Shanghai, China.
J Appl Oral Sci. 2020 Nov 4;28:e20200262. doi: 10.1590/1678-7757-2020-0262. eCollection 2020.
This study aims to replicate the phenotype of Ltbp1 knockout mice in zebrafish, and to address the function of LTBP1 in craniofacial development.
Whole mount in situ hybridization (WISH) of ltbp1 was performed at critical periods of zebrafish craniofacial development to explore the spatial-temporal expression pattern. Furthermore, we generated morpholino based knockdown model of ltbp1 to study the craniofacial phenotype.
WISH of ltbp1 was mainly detected in the mandibular jaw region, brain trunk, and internal organs such as pancreas and gallbladder. And ltbp1 colocalized with both sox9a and ckma in mandibular region. Morpholino based knockdown of ltbp1 results in severe jaw malformation. Alcian blue staining revealed severe deformity of Meckel's cartilage along with the absence of ceratobranchial. Three-dimension measurements of ltbp1 morphants jaws showed decrease in both mandible length and width and increase in open mouth distance. Expression of cartilage marker sox9a and muscle marker ckma was decreased in ltbp1 morphants.
Our experiments found that ltbp1 was expressed in zebrafish mandibular jaw cartilages and the surrounding muscles. The ltbp1 knockdown zebrafish exhibited phenotypes consistent with Ltbp1 knockout mice. And loss of ltbp1 function lead to significant mandibular jaw defects and affect both jaw cartilages and surrounding muscles.
本研究旨在复制 Ltbp1 基因敲除小鼠的表型，并研究 LTBP1 在颅面发育中的功能。
在斑马鱼颅面发育的关键时期进行 ltbp1 的全胚胎原位杂交（WISH），以探讨其时空表达模式。此外，我们还构建了 ltbp1 的基于 morpholino 的敲低模型，以研究颅面表型。
WISH 检测到 ltbp1 主要在颌骨区域、脑干和胰腺、胆囊等内脏器官中表达。并且 ltbp1 在颌骨区域与 sox9a 和 ckma 共表达。ltbp1 的 morpholino 敲低导致严重的颌骨畸形。阿辛蓝染色显示 Meckel 软骨严重畸形，同时缺乏 ceratobranchial。ltbp1 形态发生缺陷鱼的颌骨三维测量显示，下颌骨长度和宽度减小，张口距离增大。软骨标志物 sox9a 和肌肉标志物 ckma 的表达在 ltbp1 形态发生缺陷鱼中降低。
我们的实验发现，ltbp1 在斑马鱼颌骨软骨及其周围肌肉中表达。ltbp1 敲低的斑马鱼表现出与 Ltbp1 基因敲除小鼠一致的表型。ltbp1 功能丧失导致下颌骨明显缺陷，并影响颌骨软骨和周围肌肉。
