Identification of leptin-induced transcripts in the mouse hypothalamus

Long-form leptin receptor (OB-R(L)) is a signal-transducing member of the cytokine receptor superfamily that is essential for mediating the effects of leptin on mammalian body weight homeostasis. At present, the range of transcriptional targets responsive to OB-R(L) activation, and consequently, the likely mediators of leptin action, remain undefined. In this report, we have used cDNA subtractive hybridization to identify transcripts induced by leptin in immortalized hypothalamic neurons expressing OB-R(L). Differential expression of the identified transcripts in these cells was confirmed by both array technology and Northern blotting. In situ hybridization studies indicate that these transcripts are expressed in the mouse central nervous system, including nuclei of the hypothalamus that coexpress OB-R(L). Comparative in situ analysis of slices of hypothalami generated from control and leptin-injected ob/ob mice demonstrates that a subset of the identified transcripts is induced in vivo after leptin injection. The potential role of the proteins encoded by these transcripts in mediating the effects of leptin on body weight and energy homeostasis are discussed.