Primary Cilia Knockdown Reduces the Number of Stromal Cells in Three Dimensional Ex Vivo Culture

Mesenchymal stem cells (MSCs) are multipotent stromal cells that reside in the bone marrow and differentiate into connective cell lines, such as adipocytes and osteoblasts [1]. An appropriate balance of MSC differentiation toward adipocytes and osteoblasts is vital to bone homeostasis [6]. In vitro work demonstrates that differentiation of MSCs is influenced by mechanical stimuli [2, 3]. In a mouse model, the ratio of adipocytes to MSCs in the marrow was 19% lower compared to controls following treatment by low magnitude mechanical signals (LMMS) [4]. In mice, LMMS increased MSC number by 46% and the differentiation capacity of MSCs was biased towards osteoblastic compared to adipogenic differentiation [5]. Thus, mechanobiological stimuli may play an important role in maintaining balanced MSC differentiation.