Defining the Transcriptional Targets of Leptin Reveals a Role for Atf3 in Leptin Action

Abstract

Leptin acts via its receptor (LepRb) to modulate gene expression in hypothalamic LepRb-expressing neurons, thereby controlling energy balance and glucose homeostasis. Despite the importance of the control of gene expression in hypothalamic LepRb neurons for leptin action, the transcriptional targets of LepRb signaling have remained undefined because LepRb cells contribute a small fraction to the aggregate transcriptome of the brain regions in which they reside. We thus employed translating ribosome affinity purification followed by RNA sequencing to isolate and analyze mRNA from the hypothalamic LepRb neurons of wild-type or leptin-deficient ( mice treated with vehicle or exogenous leptin. Although the expression of most of the genes encoding the neuropeptides commonly considered to represent the main targets of leptin action were altered only following chronic leptin deprivation, our analysis revealed other transcripts that were coordinately regulated by leptin under multiple treatment conditions. Among these, acute leptin treatment increased expression of the transcription factor in LepRb neurons. Furthermore, ablation of from LepRb neurons (Atf3KO mice) decreased leptin efficacy and promoted positive energy balance in mice. Thus, this analysis revealed the gene targets of leptin action, including , which represents a cellular mediator of leptin action.

Hypothalamic and Cell-Specific Transcriptomes Unravel a Dynamic Neuropil Remodeling in Leptin-Induced and Typical Pubertal Transition in Female Mice

“…Of those, 562 DEGs were identified between Lep ob and WT mice ( Figure 1 C), of which 450 (80%) were upregulated and 112 (20%) were downregulated in Lep ob mice ( Figure S1 C and Table S1 ). Well-described leptin-regulated and/or energy balance-associated genes were detected: e.g., Agrp , Npy , Pmch, and Nr5a1 ( Sf1 ) were higher and Atf3 was reduced in Lep ob mice ( Allison et al., 2018 ; Elias et al., 1999 ; Elias and Purohit, 2013 ; Qu et al., 1996 ; Schwartz et al., 1996 , 1998 ).…”

“…To determine transcriptional changes in neurons directly targeted by leptin, we harvested RNA from LepRb cells by TRAP ( Heiman et al., 2014 ) and performed RNA-seq (TRAP-seq). The LepRb eGFP−L10a mice, which express a chimeric L10a ribosomal subunit fused to enhanced green fluorescent protein (eGFP-L10a), allow for eGFP immunoprecipitation of ribosomes with associated mRNAs specifically from LepRb neurons ( Allison et al., 2015 , 2018 ). This strategy enables the identification of actively transcribed mRNAs derived from PMv or Arc LepRb neurons in response to leptin administration.…”

“…As an additional control, enrichment analysis was performed comparing data from a published database using TRAP-seq and the same mouse line (i.e., LepRb eGFP−L10a Lep ob versus LepRb eGFP−L10a WT) ( Allison et al., 2015 , 2018 ). LepRb-enriched genes (beads FPKM/supernatant FPKM >1.5 = 1.5fc) were compiled and matched with the present data.…”

Co-expression network analysis predicts a key role of microRNAs in the adaptation of the porcine skeletal muscle to nutrient supply

“…A proliferation modulating function has also been described for TXNIP [72] as well as for FOSL2 [73], which is also involved in leptin expression regulation [74], whereas DEPP1 downregulation has been associated with autophagy inhibition [75]. Moreover, ssc-miR-32 and ssc-miR-7-5p, two miRNAs that were differentially upregulated in AL-T1 gilts (Table 1), were predicted to target several relevant genes (Additional file 6: Table S6) such as the activating transcription factor 3 (ATF3), a key regulator of glucose and energy metabolism [76,77] which was significantly downregulated in both AL-T0/AL-T1 and AL-T0/ AL-T2 contrasts (Additional file 2: Table S2). Other relevant additional transcripts that formed part of the miRNA-to-mRNA interconnected networks were, to mention a few, the Kruppel-like factor 15 (KLF15), early growth factor 1 (EGR1) and ARID domain-containing protein 5B (ARID5B), all of which play key roles in muscle lipid metabolism [8,78,79], or myogenin (MYOG), a gene that is crucial for muscle development and differentiation [80].…”

Molecular profiling and targeting of brain cells and circuits related to energy balance and food reward

“…Using TRAP-seq, Allison et al [10] isolated the translating mRNA of hypothalamic LepR neurons and revealed many interesting novel markers expressed in that population. In 2018, the same team explored the response of LepR neurons to leptin treatment in wild-type and ob/ob mice and identified the transcription factor Atf3 to be upregulated by leptin [117]. In 2019, Inoue et al [7], investigated the transcriptional response of hypothalamic LepR neurons to fasting and leptin administration.…”