Department of Orthopaedic Surgery, University of California San Francisco, San Francisco, CA 94143-0514, USA.
Cells Tissues Organs. 2012;196(2):99-106. doi: 10.1159/000332985. Epub 2012 Mar 1.
During in vivo stem cell differentiation, mature cells often induce the differentiation of nearby stem cells. Accordingly, prior studies indicate that a randomly mixed coculture can help transform mesenchymal stem cells (MSC) into nucleus pulposus cells (NPC). However, because in vivo signaling typically occurs heterotopically between adjacent cell layers, we hypothesized that a structurally organized coculture between MSC and NPC will result in greater cell differentiation and proliferation over single cell-type controls and cocultures with random organization.
We developed a novel bilaminar cell pellet (BCP) system where a sphere of MSC is enclosed in a shell of NPC by successive centrifugation. Controls were made using single cell-type pellets and coculture pellets with random organization. The pellets were evaluated for DNA content, gene expression, and histology.
A bilaminar 3D organization enhanced cell proliferation and differentiation. BCP showed significantly more cell proliferation than pellets with one cell type and those with random organization. Enhanced differentiation of MSC within the BCP pellet relative to single cell-type pellets was demonstrated by quantitative RT-PCR, histology, and in situ hybridization.
The BCP culture system increases MSC proliferation and differentiation as compared to single cell type or randomly mixed coculture controls.
在体内干细胞分化过程中，成熟细胞通常会诱导附近干细胞的分化。因此，先前的研究表明，随机混合共培养可以帮助间充质干细胞（MSC）转化为髓核细胞（NPC）。然而，由于体内信号通常在相邻细胞层之间异位发生，我们假设 MSC 和 NPC 之间结构上有组织的共培养将导致细胞分化和增殖超过单一细胞类型对照和随机组织的共培养。
我们开发了一种新型双层细胞球（BCP）系统，其中 MSC 的球体被 NPC 的壳包裹，通过连续离心实现。对照实验采用单细胞球和随机组织的共培养球。对小球进行 DNA 含量、基因表达和组织学评估。
双层 3D 组织增强了细胞增殖和分化。BCP 的细胞增殖显著高于单细胞球和随机组织的共培养球。定量 RT-PCR、组织学和原位杂交证明，与单细胞球相比，BCP 小球内 MSC 的分化增强。
与单细胞类型或随机混合共培养对照相比，BCP 培养系统增加了 MSC 的增殖和分化。
