NOS2 and Alzheimer disease: When we investigated the M1/M2 macrophage population and TRPV4 expression patterns, the count of TRPV4-negative, iNOS-positive macrophages was significantly increased in AD compared with healthy skin (Fig. 6B, 6E, Supplemental Fig. 4B, 4D, 4G), whereas the percentage of arginase-1–positive macrophages was not changed by TRPV4 expression (Fig. 6A, 6D, Supplemental Fig. 4A, 4C, 4F).