COVID-19 and smoking: is nicotine the hidden link?

Effect of nicotine on human bronchial epithelial cells (HBEpC) or si-mRNA-α7-HBEpC. a) Angiotensin-converting enzyme II (ACE-2) detection. ACE-2 was measured with human ACE-2 ELISA kit ab235649 (www.abcam.com/human-ace2-elisa-kit-ab235649.html) according to the manufacturer's instructions. Data are mean±sem; p-vaule was evaluated using t-test. The green plots are the human ACE-2 standard. Experiments were performed twice in triplicate. b) Induction of phospho-S6 ribosomal protein (Ser235/236), Akt1, phospho-Akt (Ser473), phospho-Akt (Thr308) and phospho-p44/42 MAPK (Thr202/Tyr204) in HBEpC. Data were obtained using PathScan® cell growth Multi-target Sandwich ELISA kit n.7239 (Cell Signaling) PathScan® Cell Growth Multi-Target Sandwich ELISA Kit is a solid phase sandwich ELISA that combines the reagents necessary to detect endogenous levels of S6 ribosomal protein, phospho-S6 ribosomal protein (Ser235/236), Akt1, phospho-Akt (Ser473), phospho-Akt (Thr308) and phospho-p44/42 MAPK (Thr202/Tyr204). Data are mean±sem; p-value was evaluated using t-test. Experiments were performed twice in duplicate. c) α7-nAChR protein detection. Western blotting was performed as described previously [11]. Human α7-nAchR antibody NBP1-49348 was purchased from Novus Biologicals (www.novusbio.com). 1–2 si-mRNA-α7-HBEpC treated with zero (lane 1) or 1.0×10⁻⁷ M nicotine (lane 2) for 1 h. 3–4 HBEpC treated with zero (lane 3) or 1.0×10⁻⁷ M nicotine (lane 4) for 1 h. Experiments were performed twice. d) as in panel b, but treated cells are si-mRNA-α7-HBEpC.