COL6A3 and obesity due to melanocortin 4 receptor deficiency: Importantly, previous studies have shown cell-type dependent expression of COL6A3, with obesity-dependent expression in adipocytes15 but higher expression in the stromal vascular fraction (SVF) of adipose tissue compared to isolated adipocytes18, expression across different adipose tissue resident monocytes/macrophages (e.g., in a nondestructive, ECM-conserving29 and potentially pro-fibrotic subtype14), and expression in different tumor cells30,31.