青少年特发性脊柱侧凸(AIS)是儿童常见的进行性脊柱畸形,表现出惊人的性二态性。与男孩相比,女孩患严重疾病的风险要高出五倍以上。尽管它的医疗影响,驱动AIS的分子机制在很大程度上是未知的。我们先前在PAX1基因附近的增强子中定义了女性特异性AIS遗传风险位点。这里,我们试图定义PAX1和新鉴定的AIS相关基因在AIS发育机制中的作用。在对10,519名AIS个体和93,238名未受影响对照的遗传研究中,与COL11A1中编码胶原蛋白(α1)XI的变体(rs3753841;NM_080629.2_c.404C>T;p。(Pro1335Leu);p=7.07E-11,OR=1.118)。使用CRISPR诱变,我们产生了Pax1敲除小鼠(Pax1-/-)。在出生后的脊柱中,我们发现PAX1和胶原蛋白(α1)XI蛋白均位于包含生长板的椎间盘-椎骨连接区域内,与野生型相比,在Pax1-/-棘中检测到的胶原蛋白(α1)XI较少。通过遗传靶向,我们发现肋软骨细胞中野生型Col11a1的表达抑制了Pax1和Mmp3的表达,编码与基质重塑有关的基质金属蛋白酶3酶。然而,在AIS相关的COL11A1P1335L突变体存在下,后一种抑制被取消.Further,我们发现,敲除雌激素受体基因Esr2或他莫昔芬治疗可显著改变软骨细胞中Col11a1和Mmp3的表达.我们提出了一种新的AIS发病机制的分子模型,其中遗传变异和雌激素信号通过改变脊髓软骨细胞中的PAX1-COL11a1-MMP3信号轴增加疾病易感性。
青少年特发性脊柱侧凸(AIS)是一种脊柱扭曲畸形,发生在全世界儿童的快速生长时期。患有严重AIS的儿童需要手术来阻止病情恶化,给卫生系统和家庭带来巨大的经济负担。尽管众所周知AIS聚集在家庭中,它的遗传原因和遗传模式仍然难以捉摸。此外,已知AIS在女性中更普遍,没有解释的偏见。研究遗传学潜在疾病的技术进步表明,某些增加AIS风险的变异会影响软骨和结缔组织。在人类中,一个这样的变异是在一个叫做Pax1的基因附近,它是女性特异性的。细胞外基质是细胞之间空间中的蛋白质和其他分子的网络,有助于将组织连接在一起,它在软骨和其他结缔组织中特别重要。细胞外基质的主要成分之一是胶原。Yu,Kanshour,Ushiki等人。假设细胞外基质的变化可能会影响脊柱的软骨和结缔组织,导致AIS。为了展示这一点,科学家筛选了超过100,000个个体,发现AIS与编码细胞外基质蛋白的两个基因的变异有关。这些变体之一是在一个名为Col11a1的基因中发现的,该基因编码构成胶原蛋白的一种蛋白质。为了理解Pax1和Col11a1之间的关系,Yu,Kanshour,Ushiki等人。转基因小鼠,使它们缺乏Pax1基因。在这些老鼠身上,小鼠脊柱中Col11a1的激活减少。他们还发现,与AIS相关的Col11a1形式不能像未突变的Col11a1那样有效地抑制小鼠软骨细胞中Mmp3基因的激活。更进一步,研究人员发现,降低雌激素受体的水平改变了小鼠软骨细胞中Pax1、Col11a1和Mmp3的激活模式。这些发现表明了AIS的可能机制,尤其是女性。Yu的发现,Kanshour,Ushiki等人。强调脊柱中的软骨细胞与AIS特别相关。结果还指出,当儿童快速成长时,细胞外基质内的特定分子对于保持脊柱的正确排列很重要。这些信息可能会指导未来旨在维持青春期儿童脊髓细胞健康的治疗方法,尤其是女孩。
Adolescent idiopathic scoliosis (AIS) is a common and progressive spinal deformity in children that exhibits striking sexual dimorphism, with girls at more than fivefold greater risk of severe disease compared to boys. Despite its medical impact, the molecular mechanisms that drive AIS are largely unknown. We previously defined a female-specific AIS genetic risk locus in an enhancer near the PAX1 gene. Here, we sought to define the roles of PAX1 and newly identified AIS-associated genes in the developmental mechanism of AIS. In a genetic study of 10,519 individuals with AIS and 93,238 unaffected controls, significant association was identified with a variant in COL11A1 encoding collagen (α1) XI (rs3753841; NM_080629.2_c.4004C>T; p.(Pro1335Leu); p=7.07E-11, OR = 1.118). Using CRISPR mutagenesis we generated Pax1 knockout mice (Pax1-/-). In postnatal spines we found that PAX1 and collagen (α1) XI protein both localize within the intervertebral disc-vertebral junction region encompassing the growth plate, with less collagen (α1) XI detected in Pax1-/- spines compared to wild-type. By genetic targeting we found that wild-type Col11a1 expression in costal chondrocytes suppresses expression of Pax1 and of Mmp3, encoding the matrix metalloproteinase 3 enzyme implicated in matrix remodeling. However, the latter suppression was abrogated in the presence of the AIS-associated COL11A1P1335L mutant. Further, we found that either knockdown of the estrogen receptor gene Esr2 or tamoxifen treatment significantly altered Col11a1 and Mmp3 expression in chondrocytes. We propose a new molecular model of AIS pathogenesis wherein genetic variation and estrogen signaling increase disease susceptibility by altering a PAX1-COL11a1-MMP3 signaling axis in spinal chondrocytes.
Adolescent idiopathic scoliosis (AIS) is a twisting deformity of the spine that occurs during periods of rapid growth in children worldwide. Children with severe cases of AIS require surgery to stop it from getting worse, presenting a significant financial burden to health systems and families. Although AIS is known to cluster in families, its genetic causes and its inheritance pattern have remained elusive. Additionally, AIS is known to be more prevalent in females, a bias that has not been explained. Advances in techniques to study the genetics underlying diseases have revealed that certain variations that increase the risk of AIS affect cartilage and connective tissue. In humans, one such variation is near a gene called Pax1, and it is female-specific. The extracellular matrix is a network of proteins and other molecules in the space between cells that help connect tissues together, and it is particularly important in cartilage and other connective tissues. One of the main components of the extracellular matrix is collagen. Yu, Kanshour, Ushiki et al. hypothesized that changes in the extracellular matrix could affect the cartilage and connective tissues of the spine, leading to AIS. To show this, the scientists screened over 100,000 individuals and found that AIS is associated with variants in two genes coding for extracellular matrix proteins. One of these variants was found in a gene called Col11a1, which codes for one of the proteins that makes up collagen. To understand the relationship between Pax1 and Col11a1, Yu, Kanshour, Ushiki et al. genetically modified mice so that they would lack the Pax1 gene. In these mice, the activation of Col11a1 was reduced in the mouse spine. They also found that the form of Col11a1 associated with AIS could not suppress the activation of a gene called Mmp3 in mouse cartilage cells as effectively as unmutated Col11a1. Going one step further, the researchers found that lowering the levels of an estrogen receptor altered the activation patterns of Pax1, Col11a1, and Mmp3 in mouse cartilage cells. These findings suggest a possible mechanism for AIS, particularly in females. The findings of Yu, Kanshour, Ushiki et al. highlight that cartilage cells in the spine are particularly relevant in AIS. The results also point to specific molecules within the extracellular matrix as important for maintaining proper alignment in the spine when children are growing rapidly. This information may guide future therapies aimed at maintaining healthy spinal cells in adolescent children, particularly girls.