– Macrophage receptor with collagenous structure (MARCO) is the predominant scavenger receptor for recognition and binding of silica particles by alveolar macrophages (AM). MARCO contributes to normal cholesterol uptake in macrophages; therefore, in the absence of MARCO, macrophages are more susceptible to a greater inflammatory response by particulates known to cause NLRP3 inflammasome activation and the effect is due to increased LMP.