Identify transcriptional regulators of Mc4r in the hypothalamus [scRNA-Seq]

Human MC4R mutations can increase or decrease obesity risk. Other than intracellular signaling, MC4R function is also influenced by its levels. However, the genetic programs that govern MC4R transcription in the brain remain largely unknown. Moreover, it is unclear whether human genetic variants exist that affect Mc4r expression and obesity risk. Here, we identify the homeodomain transcription factor Otp as one regulator of Mc4r expression in a specific subset of hypothalamic neurons. Selective loss of Otp in these neurons during development or adulthood results in reduced Mc4r expression and excessive body weight gain. Moreover, OTP interacts with upstream regulatory sequences of Mc4r to modulate its transcription. Overall design: To investigate the changes of PVH neuron populations and mRNA expressions in OtpQ153R mice, we carried out single-nucleus RNA sequencing (snRNA-seq) in the PVH of Sim1-Cre; Sun1-GFP and Sim1-Cre; Sun-GFP; Otpfl/+ and Sim1-Cre; Sun1-GFP; OtpQ153R/+ mice. Following PVH collection at four weeks old, we used fluorescence-activated cell sorting (FACS) to enrich GFP-positive nuclei from seven Sim1-Cre; Sun1-GFP mice and four Sim1-Cre; Sun-GFP; Otpfl/+ mice and six Sim1-Cre; Sun1-GFP; OtpQ153R/+ mice.