Galvan Marco, Fujitani Mina, Heaselgrave Samuel R, Thomas Shreya, Chen Bandy, Lee Jenny J, Wyler Steven C, Elmquist Joel K, Fujikawa Teppei
Center for Hypothalamic Research, Department of Internal Medicine.
Department of Neuroscience.
JCI Insight. 2025 Mar 4;10(8). doi: 10.1172/jci.insight.190105. eCollection 2025 Apr 22.
The use of genetically engineered tools, including combinations of Cre-LoxP and Flp-FRT systems, enables the interrogation of complex biology. Steroidogenic factor-1 (SF-1) is expressed in the ventromedial hypothalamic nucleus (VMH). Development of genetic tools, such as mice expressing Flp recombinase (Flp) in SF-1 neurons (Sf-1-Flp), will be useful for future studies that unravel the complex physiology regulated by the VMH. Here, we developed and characterized Sf-1-Flp mice and demonstrated their utility. The Flp sequence was inserted into the Sf-1 locus with P2A. This insertion did not affect Sf-1 mRNA expression levels and Sf-1-Flp mice do not have any visible phenotypes. They are fertile and metabolically comparable to wild-type littermate mice. Optogenetic stimulation using adeno-associated virus (AAV) carrying Flp-dependent channelrhodopsin-2 (ChR2) increased blood glucose and skeletal muscle PGC-1α in Sf-1-Flp mice. This was similar to SF-1 neuronal activation using Sf-1-BAC-Cre and AAV carrying Cre-dependent ChR2. Finally, we generated Sf-1-Flp mice that lack β2-adrenergic receptors (Adrb2) only in skeletal muscle with a combination of Cre/LoxP technology (Sf-1-Flp:SKMΔAdrb2). Optogenetic stimulation of SF-1 neurons failed to increase skeletal muscle PGC-1α in Sf-1-Flp:SKMΔAdrb2 mice, suggesting that Adrb2 in skeletal muscle is required for augmented skeletal muscle PGC-1α by SF-1 neuronal activation. Our data demonstrate that Sf-1-Flp mice are useful for interrogating complex physiology.
包括Cre-LoxP和Flp-FRT系统组合在内的基因工程工具的使用，能够对复杂生物学进行探究。类固醇生成因子1（SF-1）在下丘脑腹内侧核（VMH）中表达。开发基因工具，如在SF-1神经元（Sf-1-Flp）中表达Flp重组酶（Flp）的小鼠，将有助于未来揭示VMH调节的复杂生理学的研究。在此，我们开发并鉴定了Sf-1-Flp小鼠，并证明了它们的实用性。Flp序列通过P2A插入到Sf-1基因座中。这种插入不影响Sf-1 mRNA表达水平，Sf-1-Flp小鼠没有任何可见的表型。它们可育，代谢方面与野生型同窝小鼠相当。使用携带依赖Flp的通道视紫红质-2（ChR2）的腺相关病毒（AAV）进行光遗传学刺激，可增加Sf-1-Flp小鼠的血糖和骨骼肌PGC-1α。这与使用Sf-1-BAC-Cre和携带依赖Cre的ChR2的AAV激活SF-1神经元相似。最后，我们利用Cre/LoxP技术组合生成了仅在骨骼肌中缺乏β2-肾上腺素能受体（Adrb2）的Sf-1-Flp小鼠（Sf-1-Flp:SKMΔAdrb2）。对Sf-1-Flp:SKMΔAdrb2小鼠的SF-1神经元进行光遗传学刺激未能增加骨骼肌PGC-1α，这表明骨骼肌中的Adrb2是SF-1神经元激活增加骨骼肌PGC-1α所必需的。我们的数据表明，Sf-1-Flp小鼠有助于探究复杂生理学。
