Wolf Katarina, Alexander Stephanie, Schacht Vivien, Coussens Lisa M, von Andrian Ulrich H, van Rheenen Jacco, Deryugina Elena, Friedl Peter
Department of Cell Biology, Nijmegen Center for Molecular Life Science, Radboud University Nijmegen, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands.
Semin Cell Dev Biol. 2009 Oct;20(8):931-41. doi: 10.1016/j.semcdb.2009.08.005. Epub 2009 Aug 12.
Fibrillar collagen is the most abundant extracellular matrix (ECM) constituent which maintains the structure of most interstitial tissues and organs, including skin, gut, and breast. Density and spatial alignments of the three-dimensional (3D) collagen architecture define mechanical tissue properties, i.e. stiffness and porosity, which guide or oppose cell migration and positioning in different contexts, such as morphogenesis, regeneration, immune response, and cancer progression. To reproduce interstitial cell movement in vitro with high in vivo fidelity, 3D collagen lattices are being reconstituted from extracted collagen monomers, resulting in the re-assembly of a fibrillar meshwork of defined porosity and stiffness. With a focus on tumor invasion studies, we here evaluate different in vitro collagen-based cell invasion models, employing either pepsinized or non-pepsinized collagen extracts, and compare their structure to connective tissue in vivo, including mouse dermis and mammary gland, chick chorioallantoic membrane (CAM), and human dermis. Using confocal reflection and two-photon-excited second harmonic generation (SHG) microscopy, we here show that, depending on the collagen source, in vitro models yield homogeneous fibrillar texture with a quite narrow range of pore size variation, whereas all in vivo scaffolds comprise a range from low- to high-density fibrillar networks and heterogeneous pore sizes within the same tissue. Future in-depth comparison of structure and physical properties between 3D ECM-based models in vitro and in vivo are mandatory to better understand the mechanisms and limits of interstitial cell movements in distinct tissue environments.
纤维状胶原蛋白是细胞外基质（ECM）中最丰富的成分，它维持着包括皮肤、肠道和乳腺在内的大多数间质组织和器官的结构。三维（3D）胶原蛋白结构的密度和空间排列决定了组织的力学特性，即硬度和孔隙率，在不同情况下，如形态发生、再生、免疫反应和癌症进展中，这些特性引导或阻碍细胞迁移和定位。为了在体外以高体内保真度重现间质细胞运动，人们正在从提取的胶原蛋白单体中重构3D胶原蛋白晶格，从而重新组装出具有特定孔隙率和硬度的纤维状网络。以肿瘤侵袭研究为重点，我们在此评估不同的基于胶原蛋白的体外细胞侵袭模型，使用胃蛋白酶消化或未消化的胶原蛋白提取物，并将其结构与体内结缔组织进行比较，包括小鼠真皮和乳腺、鸡绒毛尿囊膜（CAM）和人类真皮。利用共聚焦反射和双光子激发二次谐波产生（SHG）显微镜，我们在此表明，根据胶原蛋白来源，体外模型产生具有相当窄的孔径变化范围的均匀纤维状纹理，而所有体内支架在同一组织内都包含从低密度到高密度的纤维状网络以及异质孔径范围。未来必须对基于3D ECM的体外和体内模型之间的结构和物理特性进行深入比较，以更好地理解不同组织环境中间质细胞运动的机制和局限性。
