Role of canonical transient receptor potential channel-3 in acetylcholine-induced mouse airway smooth muscle cell proliferation.

AIMS: Canonical transient receptor potential channel-3 (TRPC3)-encoded Ca(2+)-permeable nonselective cation channel (NSCC) has been proven to be an important native constitutively active channel in airway smooth muscle cell (ASMC), which plays significant roles in physiological and pathological conditions by controlling Ca(2+) homeostasis in ASMC. Acetylcholine (ACh) is generally accepted as a contractile parasympathetic neurotransmitter in the airway. Recently studies have revealed the pathological role of ACh in airway remodeling, however, the mechanisms remain unclear. Here, we investigated the role of TRPC3 in ACh-induced ASMC proliferation.

MATERIALS AND METHODS: Primary mouse ASMCs were cultured with or without ACh treatment, then cell viability, TRPC3 expression, NSCC currents and [Ca(2+)]i changes were examined by MTT assay, cell counting, Western blotting, standard whole-cell patch clamp recording and calcium imaging, respectively. Small interfering RNA (siRNA) technology was used to confirm the contribution of TRPC3 to ACh-induced ASMC proliferation.

KEY FINDINGS: TRPC3 blocker Gd(3+), antibody or siRNA largely inhibited ACh-induced up-regulation of TRPC3 protein, enhancement of NSCC currents, resting [Ca(2+)]i and KCl-induced changes in [Ca(2+)]i, eventually inhibiting ACh-induced ASMC proliferation.

SIGNIFICANCE: Our data suggested ACh could induce ASMC proliferation, and TRPC3 may be involved in ACh-induced ASMC proliferation that occurs with airway remodeling.