Macrophages and other immune cells are important contributors to obesity‐associated inflammation; however, the cellular identities of these specific populations remain unknown. In this study, we identified individual populations of myeloid cells found in mouse epididymal/visceral adipose tissue by single‐cell RNA sequencing, immunofluorescence, and flow cytometry. Multiple canonical correlation analysis identified 11 unique myeloid and myeloid‐associate cell populations. In obese mice, we detected an increased percentage of monocyte‐derived pro‐inflammatory cells expressing Cd9 and Trem2, as well as significantly decreased percentages of multiple cell populations, including tissue‐resident cells expressing Lyve1, Mafb, and Mrc1. We have identified and validated a novel myeloid/macrophage population defined by Ly6a expression, exhibiting both myeloid and mesenchymal characteristics, which increased with obesity and showed high pro‐fibrotic characteristics in vitro. Our mouse adipose tissue myeloid cell atlas provides an important resource to investigate obesity‐associated inflammation and fibrosis.

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Previous studies have shown smooth muscle induction in adipose-derived mesenchymal stem cells (ASCs) caused by long-term cyclic stretch. Here we examined the capability of the short-term straining with time steps of 4, 8, 16 and 24 h alone or combined with TGF-β1 on smooth muscle induction of rabbit ASCs. Alterations in cell morphology were quantified through the cell shape index and orientation angle, and expression levels of α-SMA, SM22-α, h-caldesmon and calponin3 markers were examined using the real-time polymerase chain reaction (PCR) method. Moreover, F-actin cytoskeleton organization was observed by fluorescence staining. Mechanical strain either alone or combined with growth factor treatment caused significant up-regulation of both early and intermediate smooth muscle cells (SMCs) specific markers during the initial hours of stimulation peaking in 8 to 16 h. Furthermore, gradual alignment of cells perpendicular to the strain direction during loading time, and cell elongation resembling contractile SMC phenotype, together with alignment and reorganization of F-actin fibers were observed. Considering previously reported protein up-regulation in following days of straining, the effects of short-term cyclic stretch on smooth muscle induction of ASCs were revealed which can be helpful in achieving functional contractile SMCs through synergistic mechano-chemical regulation of ASCs as an appealing cell source for vascular tissue engineering.