Control of adipose function through a PRDM16/Type 1 Interferon Axis

摘要 在美国，肥胖是导致慢性病和过早死亡的主要原因。 肥胖和相关疾病是通过增加燃烧能量的棕色和米色的活动来实现的 脂肪细胞。除了促进脂肪流失，棕色脂肪细胞还有能力消耗大量的 脂肪和葡萄糖，从而减少它们在许多组织中的毒性作用。PRDM16，一种锌指转录 因子在调节棕色和米色脂肪细胞分化中起着关键作用。我们最近发现， 除了驱动棕色脂肪选择基因程序外，PRDM16还有效地抑制转录 脂肪细胞和组织对天然免疫1型干扰素信号的反应。此外，我们发现， 1型干扰素信号，主要与病毒感染有关，在脂肪组织中通过 高脂饮食和1型干扰素的激活抑制了脂肪细胞的线粒体功能。这些令人兴奋的东西 这些发现导致我们假设PRDM16介导的对1型干扰素信号的抑制保留了 棕色脂肪在正常生理条件下的生热功能。然而，我们推测， 高脂饮食引起的1型干扰素信号的持续增加导致棕色动物线粒体功能障碍 脂肪，在这样做的过程中，极大地促进了全身代谢性疾病的发展。在这个项目中， 我们将研究PRDM16阻断脂肪细胞中干扰素反应的机制，并确定 1型干扰素在高脂饮食诱导的体重增加和全身性胰岛素抵抗中的作用。在目标1中，我们 将确定PRDM16被招募到干扰素反应基因的机制，并研究PRDM16如何 在染色质中起作用，以抑制这些基因的转录。在目标2中，我们将使用细胞培养和体内 检测PRDM16和1型干扰素信号在调节棕色脂肪中相互作用的遗传模型 功能。在目标3中，我们将确定是否可以阻断脂肪中与高脂饮食相关的1型干扰素反应 用于减少代谢性疾病。总之，这些研究将定义PRDM16和类型1的新角色 干扰素信号在调节脂肪生物学和系统代谢中的作用。

Summary Obesity is a leading cause of chronic illness and premature death in the U.S. A promising avenue to reduce obesity and associated diseases is through increasing the activity of energy-burning brown and beige adipocytes. In addition to promoting fat loss, brown fat cells have the capacity to consume large amounts of lipid and glucose and thereby reduce their toxic actions in many tissues. PRDM16, a zinc-finger transcription factor plays a critical role in regulating brown and beige adipocyte differentiation. We recently discovered that, in addition to driving a brown fat-selective gene program, PRDM16 powerfully suppresses transcriptional responses to innate immune type 1 Interferon (IFN) signaling in adipose cells and tissues. Moreover, we found that Type 1 IFN signaling, which is primarily associated with viral infection, is elevated in adipose tissues by high fat diet and that type 1 IFN activation represses mitochondrial function in adipocytes. These exciting findings led us to hypothesize that PRDM16-mediated suppression of Type 1 IFN-signaling preserves the thermogenic function of brown fat under normal physiological conditions. However, we speculate that persistent increases in type 1 IFN signaling caused by high fat diet leads to mitochondrial dysfunction in brown fat and, in doing so, contributes significantly to the development of systemic metabolic disease. In this project, we will investigate the mechanisms by which PRDM16 blocks the IFN-response in adipose cells and determine the role of type 1 IFN in driving high fat diet-induced weight gain and systemic insulin resistance. In aim 1, we will determine the mechanism by which PRDM16 is recruited to IFN-responsive genes and study how PRDM16 functions in chromatin to repress the transcription of these genes. In aim 2, we will use cell culture and in vivo genetic models to examine the interaction between PRDM16 and type 1 IFN-signaling in regulating brown fat function. In Aim 3, we will determine if blocking high fat diet-linked type 1 IFN-responses in adipose could be used to reduce metabolic disease. Altogether, these studies will define a novel role for PRDM16 and type 1 IFN signaling in regulating adipose biology and systemic metabolism.