Twist1 mRNA expression was also 2.2-times higher in ECs isolated from Lepob/+ mouse lungs 7 days after PNX, while the levels of Twist1 did not significantly change in post-PNX Lepob/ob mouse lung ECs (Figure 2F), suggesting that obesity inhibits post-PNX induction of Twist1 expression. This evidence concerns the gene TWIST1 and obesity due to melanocortin 4 receptor deficiency.