Wyler, S. C. | Search bioRxiv

bioRxiv2025

Development and Characterization of a Sf-1-Flp Mouse Model

The use of genetically engineered tools, including combinations of Cre-LoxP and Flp-FRT systems, enable 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 its utility. Flp sequence was inserted into 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)-bearing Flp-dependent channelrhodopsin-2 (ChR2) increased blood glucose and skeletal muscle PGC-1 in Sf-1-Flp mice. This was similar to SF-1 neuronal activation using Sf-1-BAC-Cre and AAV-bearing Cre-dependent ChR2. Finally, we generated Sf-1-Flp mice that lack {beta}2-adrenergic receptors (Adr{beta}2) only in skeletal muscle with a combination of Cre/LoxP technology (Sf-1-Flp::SKM{Delta}Adr{beta}2). Optogenetic stimulation of SF-1 neurons failed to increase skeletal muscle PGC-1 in Sf-1-Flp::SKM{Delta}Adr{beta}2 mice, suggesting that Adr{beta}2 in skeletal muscle is required for augmented skeletal muscle PGC-1 by SF-1 neuronal activation. Our data demonstrate that Sf-1-Flp mice are useful for interrogating complex physiology.

neuroscience↗

bioRxiv2019

Transcriptomic Profiling of Developing Melanocortin Neurons Reveals a Role for Prdm12 in Energy Balance

The hypothalamus is a critical regulator of many physiological processes essential for life. In the adult brain, each anatomically-defined hypothalamic nucleus consists of functionally heterogeneous neuronal subpopulations that dictate distinct survival behaviors. Nevertheless, how rich neuronal identities are established in the developing hypothalamus remains poorly understood.\n\nDespite their opposing actions on food intake, POMC and NPY/AgRP neurons in the arcuate nucleus of the hypothalamus (ARH) are derived from the same progenitors that give rise to ARH neurons. However, the mechanism whereby common neuronal precursors subsequently adopt either the anorexigenic (POMC) or the orexigenic (NPY/AgRP) identity remains elusive.\n\nWe hypothesize that POMC and NPY/AgRP cell fates are specified and maintained by distinct intrinsic factors. In search of them, we profiled the transcriptomes of developing POMC and NPY/AgRP neurons with whole-genome RNA sequencing (RNA-seq). Moreover, cell-type-specific transcriptomic analyses revealed transcription regulators that are selectively enriched in either population, but whose developmental functions are unknown in these neurons.\n\nAmong them, we found the expression of the PR domain-containing factor 12 (Prdm12) was enriched in POMC neurons but was absent in NPY/AgRP neurons. Selective ablation of Prdm12 in postmitotic POMC neurons led to early-onset obesity, accelerated linear growth, as well as impaired glucose tolerance, which recapitulates symptoms of POMC/MC4R deficiency in humans. These findings, therefore, establish a previously-unrecognized role for Prdm12 in energy balance. Furthermore, the combination of cell-type-specific genomic and genetic analyses provides a means to dissect cellular and functional diversity in the developing hypothalamus as well as the developmental origins of diverse survival behaviors.

neuroscience↗