Thymic stromal lymphopoietin (TSLP) is a novel cytokine that triggers dendritic cell-mediated T helper (Th) ₂ inflammatory responses. Previous studies have demonstrated that human airway smooth muscle cells (HASMC) play a critical role in initiating or perpetuating airway inflammation by producing chemokines and cytokines. In this study, we first evaluated the expression of TSLP in primary HASMC and investigated how pro-inflammatory cytokines (TNF- and IL-1) and Th-2 cytokines (IL-4, IL-9) regulate TSLP production from HASMC. TSLP mRNA and protein were assessed by real-time RT-PCR, ELISA and immunofluorescence from primary HASMC cultures. Primary HASMC express constitutive level of TSLP. Incubation of HASMC with IL-1, TNF- resulted in a significant increase of TSLP mRNA and protein release from HASMC. Furthermore, combination of IL-1 and TNF- has an additive effect on TSLP release by HASMC. Primary HASMC pretreated with inhibitors of p38 or p42/p44 ERK MAPK, but not PI3K, showed a significant decrease in TSLP release upon IL-1 and TNF- treatment. Furthermore, TSLP immunoreactivity was present in ASM bundle from Chronic Obstructive Pulmonary Disease (COPD) and to lesser degree in normal subjects. Taken together, our data provide the first evidence of IL-1 and TNF- -induced TSLP expression in HASMC via (p38, p42/p44) MAPK signaling pathways. Our results raise the possibility that HASMC may play a role in COPD airway inflammatory via TSLP dependent pathway.