Background: The COVID-19 pandemic is an ongoing threat to public health. Since the identification of COVID-19, the disease caused by SARS-CoV-2, no drugs have been developed to specifically target SARS-CoV-2. To develop effective and safe treatment options, a better understanding of cellular mechanisms underlying SARS-CoV-2 infection is required. To fill this knowledge gap, researchers require reliable experimental systems that express the host proteins necessary for the cellular entry of SARS-CoV-2. These proteins include the viral receptor, ACE2 and the proteases TMPRSS2 and furin. A number of studies have reported cell-type specific expression of the genes encoding these molecules. However, less is known about the protein expression of these molecules. Methods: We assessed the suitability of primary human bronchial epithelial (HBE) cells maintained in air-liquid interface (ALI) as an experimental system for studying SARS-CoV-2 infection in vitro. During cellular differentiation, we measured the expression of ACE2, TMPRSS2, and furin over progressive ALI days by RT-qPCR, western blot and immunofluorescence staining. We also explored the effect of the fibrotic cytokine TGF-b on the expression of these proteins in well-differentiated HBE cells. Results/Discussion: Like ACE2, TMPRSS2 and furin proteins are localized in differentiated ciliated cells as confirmed by immunofluorescence staining. These data suggest that well-differentiated HBE cells maintained in air-liquid interface is a reliable in vitro system for investigating cellular mechanisms of SARS-CoV-2 infection. We further identified that profibrotic mediators, TGF-β1 and TGF-β2, increase the expression of furin, which is a protease required for the cellular entry of SARS-CoV-2.