Department of Dermatology and Cutaneous Biology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA.
Connect Tissue Res. 2012;53(5):379-89. doi: 10.3109/03008207.2012.668252. Epub 2012 Apr 10.
The integrity of skin depends on a complex system of extracellular matrix molecules that form a biological scaffold. One of its elements is the dermal basement membrane that provides a link between the epidermis and the dermis. Mutations in collagen VII, a key component of the dermal membrane zone, are associated with dystrophic epidermolysis bullosa. Although it has been proposed that silencing the mutated COL7A1 allele is a promising approach to restore the dermal basement membrane zone formed in the presence of collagen VII mutants, limitations exist to testing this proposal. Here, we employed a model that utilized skin-like constructs in which engineered collagen VII mutant chains harboring the R2622Q or G2623C substitution were expressed conditionally, but the wild-type chains were expressed unconditionally. We demonstrated that switching off the production of the mutant collagen VII chains in skin constructs restores the organization of collagen VII and laminin 332 deposits in the dermal-epidermal junction to the level of control. We also demonstrated that remodeling of collagen IV deposits was not fully effective after silencing the expression of collagen VII mutants. Thus, our study suggests that while silencing mutant alleles of COL7A1 may repair critical elements of the affected dermal basement membrane, it may not be sufficient to fully remodel its entire architecture initially formed in the presence of the mutant collagen VII chains.
皮肤的完整性取决于细胞外基质分子的复杂系统，这些分子形成生物支架。其元素之一是真皮基底膜，它为表皮和真皮之间提供了连接。VII 型胶原的突变，是真皮膜区的关键组成部分，与营养不良性大疱性表皮松解症有关。虽然有人提出沉默突变的 COL7A1 等位基因是一种有前途的方法，可以恢复存在 VII 型胶原突变体时形成的真皮基底膜区，但对这一建议进行测试存在局限性。在这里，我们采用了一种模型，该模型利用皮肤样构建体，其中表达条件性的工程化 VII 型胶原突变链，携带 R2622Q 或 G2623C 取代，但野生型链是无条件表达的。我们证明，在皮肤构建体中关闭突变型胶原 VII 链的产生，可以将胶原 VII 和层粘连蛋白 332 在真皮-表皮交界处的沉积的组织恢复到对照水平。我们还证明，沉默突变型胶原 VII 的表达后，胶原 IV 沉积的重塑并不完全有效。因此，我们的研究表明，尽管沉默 COL7A1 的突变等位基因可能修复受影响的真皮基底膜的关键成分，但这可能不足以完全重塑其最初在突变型胶原 VII 链存在下形成的整个结构。
