Interestingly, we found p16INK4a mRNA expression was suppressed in lungs from Ec‐TLR4‐reconstit X TLR4−/− mice compared to TLR4−/− (Figure 3n), suggesting that Ec‐TLR4 negatively regulates p16INK4a expression in lungs that exhibit early emphysema. The gene discussed is CDKN2A; the disease is pulmonary emphysema.