Bidirectional crosstalk between T lymphocytes and airway smooth muscle

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Contact of T cells with airway smooth muscle (ASM) cells triggers its growth and in turn ASM enhances T cell survival and proliferation. Interfering with contact augments T cell apoptosis and also interferes with ASM proliferation. A novel method of communication between the cells is through nanotubes, thin cellular projections from T cells to ASM. We demonstrated that anti-apoptotic factors such as Bcl2 and Mcl1 were present within the nanotubes and we have observed mitochondrial transfer from ASM to T cells. We have demonstrated a role for basic fibroblast growth factor-2 (bFGF-2) in nanotube formation (Appendix 4). However we know little of the biological consequences of communication via nanotubes between these cell types. The general hypothesis is that CD4+ T cells communicate with ASM cells via nanotubes that affect both ASM and T cell biology. To understand the biological consequences of nanotube formation between T cells and ASM cells, the drivers of the nanotube formation and the alterations in properties of the cells consequent upon this intercellular communication we will pursue the following general areas of research:****Aim 1: To determine the structure of the contact area of T cell nanotubes with ASM cells****Whether the T cell nanotube connection with ASM is similar to an immunological synapse will be investigated in this aim by examining the junction for the presence of the T cell receptor, MHC class II molecules, CD44, and co-stimulatory molecules.****Aim 2: To determine the role of growth factors in human CD4 T cell-driven ASM proliferation and in T cell activation and proliferation****The role basic fibroblast growth factor-2 and epidermal growth factor receptor ligands have in ASM proliferation and T cell activation and proliferation when T cells and ASM are in contact will be examined.****Aim 3: To explore the significance of mitochondrial transfer from ASM to T cells for T cell survival and function****We will test the effects of the inhibition of the movement of mitochondria from ASM to T cells via nanotubes by inhibiting motor proteins on T cell survival, metabolism and proliferation. We will nanofabricate culture plates to allow ASM and T cells to be cultured separately but with intervening channels to permit nanotubes to be formed between the cells.****Aim 4: To determine the effects of T cell contact with ASM cells on ASM contractile properties****Histamine induced calcium signals within ASM cells are reduced when in contact with T cells. We will examine the underlying molecular mechanisms. In addition we will explore the effects of the inhibition of nanotube formation on calcium signals by administering FGFR1 and EGFR inhibitors and anti-CD44 in concentrations that do not induce T cell apoptosis.****Anticipated results: We anticipate that we will elucidate the biological significance of cell to cell communication mediated by contact-dependent mechanisms between T cells and ASM cells.******