title: PPARγ mRNA in the adult mouse hypothalamus: distribution and regulation in response to dietary challenges.
abstract: Peroxisome proliferator-activated receptor gamma (PPARγ) is a ligand-activated transcription factor that was originally identified as a regulator of peroxisome proliferation and adipocyte differentiation. Emerging evidence suggests that functional PPARγ signaling also occurs within the hypothalamus. However, the exact distribution and identities of PPARγ-expressing hypothalamic cells remains under debate. The present study systematically mapped PPARγ mRNA expression in the adult mouse brain using in situ hybridization histochemistry. PPARγ mRNA was found to be expressed at high levels outside the hypothalamus including the neocortex, the olfactory bulb, the organ of the vasculosum of the lamina terminalis (VOLT), and the subfornical organ. Within the hypothalamus, PPARγ was present at moderate levels in the suprachiasmatic nucleus (SCh) and the ependymal of the 3rd ventricle. In all examined feeding-related hypothalamic nuclei, PPARγ was expressed at very low levels that were close to the limit of detection. Using qPCR techniques, we demonstrated that PPARγ mRNA expression was upregulated in the SCh in response to fasting. Double in situ hybridization further demonstrated that PPARγ was primarily expressed in neurons rather than glia. Collectively, our observations provide a comprehensive map of PPARγ distribution in the intact adult mouse hypothalamus.
authors.affiliation: Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA ; Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology Wuhan, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA.
authors.forename: Ying
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA.
authors.forename: Syann
authors.initials: S
authors.lastname: Lee
authors.affiliation: Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA.
authors.forename: Angie L
authors.initials: AL
authors.lastname: Bookout
authors.affiliation: Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA.
authors.forename: Carlos M
authors.initials: CM
authors.lastname: Castorena
authors.affiliation: Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology Wuhan, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Wu
authors.affiliation: Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA.
authors.forename: Laurent
authors.initials: L
authors.lastname: Gautron
keywords: confocal laser scanning microscopy; hypothalamus; in situ hybridization; mouse brain; transcription factors