Transient receptor potential channel subfamily A member 1 (TRPA1) is a non-selective cationic channel, identified initially as a cold sensory receptor. TRPA1 responds to diverse exogenous and endogenous stimuli associated with pain and inflammation. However, the information on the role of TRPA1 toward T-cell responses remains scanty. In silico data suggest that TRPA1 can play an important role in the T-cell activation process. In this work, we explored the endogenous expression of TRPA1 and its function in T cells. By reverse transcription polymerase chain reaction (RT-PCR), confocal microscopy and flow cytometry, we demonstrated that TRPA1 is endogenously expressed in primary murine splenic T cells as well as in primary human T cells. TRPA1 is primarily located at the cell surface. TRPA1-specific activator namely allyl isothiocyanate (AITC) increases intracellular calcium ion (Ca2+) levels while two different inhibitors namely A-967079 as well as HC-030031 reduce intracellular Ca2+ levels in T cells; TRPA1 inhibition also reduces TCR-mediated calcium influx. TRPA1 expression was found to be increased during αCD3/αCD28 (TCR) or Concanavalin A (ConA)-driven stimulation in T cells. TRPA1-specific inhibitor treatment prevented induction of cluster of differentiation 25 (CD25), cluster of differentiation 69 (CD69) in ConA/TCR stimulated T cells and secretion of cytokines like tumor necrosis factor (TNF), interferon γ (IFN-γ), and interleukin 2 (IL-2) suggesting that endogenous activity of TRPA1 may be involved in T-cell activation. Collectively these results may have implication in T cell-mediated responses and indicate possible role of TRPA1 in immunological disorders.

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A major limitation in the bio-medical sector is the availability of materials suitable for bone tissue engineering using stem cells and methodology converting the stochastic biological events towards definitive as well as efficient bio-mineralization. We show that osteoblasts and Bone Marrow-derived Mesenchymal Stem Cell Pools (BM-MSCP) express TRPM8, a Ca2+-ion channel critical for bone-mineralization. TRPM8 inhibition triggers up-regulation of key osteogenesis factors; and increases mineralization by osteoblasts. We utilized CMT:HEMA, a carbohydrate polymer-based hydrogel that has nanofiber-like structure suitable for optimum delivery of TRPM8-specific activators or inhibitors. This hydrogel is ideal for proper adhesion, growth, and differentiation of osteoblast cell lines, primary osteoblasts, and BM-MSCP. CMT:HEMA coated with AMTB (TRPM8 inhibitor) induces differentiation of BM-MSCP into osteoblasts and subsequent mineralization in a dose-dependent manner. Prolonged and optimum inhibition of TRPM8 by AMTB released from the gels results in upregulation of osteogenic markers. We propose that AMTB-coated CMT:HEMA can be used as a tunable surface for bone tissue engineering. These findings may have broad implications in different bio-medical sectors.

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