Pref-1 receptor: Identification and characterization in inhibiting adipogenesis

Pref-1(Preadipocell factor-1)是我们首次克隆和鉴定的一种广泛使用的前体脂肪细胞标志物。Pref-1在前脂肪细胞中表达，在脂肪细胞分化过程中表达下调，在脂肪细胞中不表达。Pref-1是以质膜蛋白的形式合成的，在胞外区有6个EGF重复序列。Pref-1胞外结构域被TACE切割生成具有生物活性的可溶性Pref-1。培养细胞和小鼠体内的功能获得和丧失研究表明，Pref-1以自分泌/旁分泌的方式抑制脂肪生成。因此，尽管去除Pref-1的小鼠有更高的脂肪组织质量，但在脂肪组织中过表达Pref-1会导致部分脂肪营养不良，并伴有异位脂肪储存。Pref-1激活MEK/ERK诱导Sox9，进而抑制C/EBpb和C/EBPd，从而抑制脂肪细胞分化。然而，启动Pref-1信号转导的细胞膜上的Pref-1受体尚不清楚。通过使用最近开发的二氮杂光反应连接物结合NHS-酯原位化学，最近发现了推测为Pref-1的质膜受体。本研究的目的是建立和鉴定Pref-1信号最近端和最关键的成分Pref-1受体，并研究其下游抑制脂肪细胞分化的成分。为了实现这一目标，将采取生化、细胞和分子方法以及体外和体内功能的得失研究。从长远来看，阐明Pref-1与Pref-1受体及其下游信号通路结合的潜在机制将有助于制定控制脂肪形成的策略。

Pref-1 (Preadipocyte factor-1) is a widely used preadipocyte marker that we originally cloned and identified. Pref-1 is expressed in preadipocytes, downregulated during adipocyte differentiation, and is absent in adipocytes. Pref-1 is synthesized as a plasma membrane protein with 6 EGF-repeats in the extracellular domain. Pref-1 ectodomain is cleaved by TACE to generate the biologically active soluble Pref-1. Gain- and loss-of function studies in cultured cells, as well as in mice in vivo showed Inhibition of adipogenesis by Pref-1 in autocrine/paracrine manner. Thus, whereas Pref-1ablated mice have higher adipose tissue mass, Pref-1 overexpression in adipose tissue causes partial lipodystrophy with ectopic fat storage. Pref-1 activates MEK/ERK to induce Sox9, which in turn suppresses C/EBPb and C/EBPd, to inhibit adipocyte differentiation. However, the Pref-1 receptor at the plasma membrane that initiates Pref-1 signaling is yet to be identified. By using recently developed diazirine photo-reactive linker combined with robust NHS-ester chemistry in situ, the putative plasma membrane receptor for Pref-1 has recently been identified. The goal of this research is to firmly establish and characterize the Pref-1 receptor which is the most proximal and critical component of Pref-1 signaling and to study the downstream components to inhibit adipocyte differentiation. To accomplish this goal, biochemical, cellular and molecular approaches as well as gain- and loss-of function studies in vitro and in vivo will be taken. In the long run, elucidating mechanisms underlying Pref-1 binding to the Pref-1 receptor and its downstream signaling pathway will help to develop strategies to control adipogenesis.