Now showing 1 - 2 of 2
  • Publication
    Primary cilium-associated genes mediate bone marrow stromal cell response to hypoxia
    Currently there is intense interest in using mesenchymal stem cells (MSC) for therapeutic interventions in many diseases and conditions. To accelerate the therapeutic use of stem cells we must understand how they sense their environment. Primary cilia are an extracellular sensory organelle present on most growth arrested cells that transduce information about the cellular environment into cells, triggering signaling cascades that have profound effects on development, cell cycle, proliferation, differentiation and migration. Migrating cells likely encounter differing oxygen tensions, therefore we investigated the effect of oxygen tension on cilia. Using bone marrow stromal cells (BMSCs, also known as bone marrow-derived mesenchymal stem cells) we found that oxygen tension significantly affected the length of cilia in primary BMSCs. Chronic exposure to hypoxia specifically down-regulated genes involved in hedgehog signaling and re-localized the Smo and Gli2 proteins to cilia. Investigating the effects of chemotactic migration on cilia, we observed significantly longer cilia in migrating cells which was again, strongly influenced by oxygen tension. Finally, using computational modeling we identified links between migration and ciliation signaling pathways, characterizing the novel role of HSP90 and PI3K signaling in regulating BMSC cilia length. These findings enhance our current understanding of BMSC adaptions to hypoxia and advance our knowledge of BMSC biology and cilia regulation.
    Scopus© Citations 16  573
  • Publication
    ROCK activity and the Gβγ complex mediate chemotactic migration of mouse bone marrow-derived stromal cells
    Bone marrow-derived stromal cells (BMSCs), also known as mesenchymal stem cells, are the focus of intensive efforts worldwide to elucidate their function and biology. Despite the importance of BMSC migration for their potential therapeutic uses, the mechanisms and signalling governing stem cell migration are still not fully elucidated. Methods: We investigated and detailed the effects of MCP-1 activation on BMSCs by using inhibitors of G protein-coupled receptor alpha beta (GPCR αβ), ROCK (Rho-associated, coiled-coil containing protein kinase), and PI3 kinase (PI3K). The effects of MCP-1 stimulation on intracellular signalling cascades were characterised by using immunoblotting and immunofluorescence. The effectors of MCP-1-mediated migration were investigated by using migration assays (both two-dimensional and three-dimensional) in combination with inhibitors. Results: We established the kinetics of the MCP-1-activated signalling cascade and show that this cascade correlates with cell surface re-localisation of chemokine (C motif) receptor 2 (CCR2) (the MCP-1 receptor) to the cell periphery following MCP-1 stimulation. We show that MCP-1-initiated signalling is dependent on the activation of βγ subunits from the GPCR αβγ complex. In addition, we characterise a novel role for PI3Kγ signalling for the activation of both PAK and ERK following MCP-1 stimulation. We present evidence that the Gβγ complex is responsible for PI3K/Akt, PAK, and ERK signalling induced by MCP-1 in BMSCs. Importantly, we found that, in BMSCs, inhibition of ROCK significantly inhibits MCP-1-induced chemotactic migration, in contrast to previous reports in other systems.Conclusions: Our results indicate differential chemotactic signalling in mouse BMSCs, which has important implications for the translation of in vivo mouse model findings into human trials. We identified novel components and interactions activated by MCP-1-mediated signalling, which are important for stem cell migration. This work has identified additional potential therapeutic targets that could be manipulated to improve BMSC delivery and homing.
      323Scopus© Citations 14