MMP9 and chronic obstructive pulmonary disease: However, miR-570-3p inhibition in COPD SAECs significantly reduced the normally elevated levels of both protein and mRNA expression of MMP-2 and MMP-9 (Fig. 7A–C), while inhibition of miR-570-3p in COPD SAECs also decreased CXCL8, IL-6, and IL-1β release (Fig. 7D–F).