mTORC1 and Autophagy in Human Brown Adipocytes

Specific Aim 1: To investigate the role of mTORC1 and autophagy in regulating thermogenesis in human brown adipocytes. The working hypothesis is that inhibition of mTORC1 or activation of autophagy improves thermogenesis in human brown adipocytes. It will be first determined if the mTORC1/autophagy signaling modulates thermogenic gene expression and beige markers by collecting human brown fat from lean non-diabetic subjects. The brown fat during the anterior cervical spine surgery or thyroidectomy from lean subjects with a BMI <25, or obese participants who have a BMI >30, will be harvested and then be used to determine: 1) whether mTORC1 signaling, autophagy and thermogenic gene expression, and the fraction of various types of immune cells in human brown fat are different from those in rodents;2) whether rapamycin treatment enhances basal or CL-induced thermogenic gene expression and O2 consumption in primary human brown adipocytes; and 3) whether inhibition of autophagy by 3-methyladenine (3-MA) suppresses thermogenic gene expression induced by CL316,243, a β3-adrenoceptor agonist that mimics cold stress in vivo in human brown adipocytes.

Overall, this study will lead to the identification of mTORC1 as a key regulator of thermogenesis in human adipose tissue and reveal promising new anti-obesity drug targets. In addition, this study will further investigate the role of rapamycin administration in obesity in human adults near the future. These studies are designed to be a proof-of-principle. If the results are promising, then future drug development could focus on designing new inhibitors of mTORC1.

Inclusion criteria

• Male or Female
• age 18-60
• able to give informed consent
• non-diabetic
• scheduled for anterior cervical spine, thyroidectomy, or parathyroidectomy surgery at UNMHSC
• BMI <25 (lean) or >30 (obese)
• English or Spanish speaking

Exclusion criteria

• has diabetes mellitus (type I or II)
• currently on any study medication (including sedatives or analgesics, coagulopathy (INR of 1.5 or greater, platelet count of <50,000/microliter), or anticoagulant)
• pregnant
• incarcerated