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Leptin Receptor Ablation in Anterior Pituitary Somatotropes Reveals Broad Transcriptomic Changes and Sex-Specific Signaling Pathways

ABSTRACT: Anterior pituitary somatotropes utilize metabolic signals from the adipokine leptin to optimize responses to the body’s nutritional state via expression of growth hormone (GH), growth hormone releasing hormone receptors (GHRHR) and their transcriptional regulator POU1F1. To identify the mechanism underlying leptin action upon somatotropes, we analyzed single cell transcriptomes of pituitaries from somatotropes lacking leptin receptors (LEPR-null) compared with control pituitaries. Computational clustering of results identified all common pituitay cell types plus 5 undefined (UND) clusters. Differentially expressed genes (DEGs) (Log2FC0.58; adjusted p<0.055 thresholds) in mutant males revealed effects upon both transcriptional and mRNA translation regulators, but not direct effects upon hormone mRNA expression. Dysfunction in the male mutant LEPR-null somatotrope cluster was indicated by down-regulated genes in key transcriptional and second messenger signaling pathways, which were mostly upregulated in mutant females. Furthermore, mutant female somatotrope dysfunction was indicataed by an increase in markers for pituitary stem and/or progenitor cells (e.g.Sox9) and also increases (0.67-2.6-fold) in non-somatotrope hormone DEGs, e.g. Pomc, Lhb, Tshb, Cga, and/or Prl in female somatotrope, lactotrope, thyrotrope, corticotrope, and the UND3 clusters. Gh mRNA was decreased in mutant female somatotrope, UND2 and UND3 clusters. Collectively the increases in multihormonal expression did not coincide with increased expression of receptors for their releasing hormones. This and the presence of Sox9 suggested that the female somatotropes presented an immature gene signature. Collectively, these data point to a trophic role for leptin in the differentiation and/or maturation of somatotropes through regulatory pathways that are unique to each sex.

ORGANISM(S): Mus musculus

PROVIDER: GSE276468 | GEO | 2025/02/19

REPOSITORIES: GEO

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Project description:Leptin receptors (Lepr) are expressed by various types of stem cells including mesenchymal stem cells, hematopoietic stem cells, embryonic stem cells, and induced pluripotent stem cells. Leptin/lepr signaling is also a central regulator of metabolism. However, the role of Lepr in pluripotency, metabolic disease progression and growth development is still controversial and poorly understood. In the present study, we explored the Lepr function in disease progression, pluripotency and metabolism using day 14.5 mouse embryonic fibroblasts (MEFs) and their reprogrammed induced pluripotent stem cells (iPSCs) as model system. We successfully reprogrammed mouse embryonic fibroblasts into iPSCs from control and db/db (Lepr deficient) mice. Using a global quantitative proteomic approach, we identified key pathways regulating pluripotency, metabolic homeostasis and protein synthesis during fetal growth and development. The Lepr MEFs show abnormal metabolic abnormalities and mitochondrial dysfunction as compared to control MEFs, while Lepr iPSCs show upregulated elongated factor 4 e (eIF4e) protein synthesis pathway and altered Oct4 and Stat3 pathways which are involved in normal fetal growth development. Furthermore, chip analysis revealed that higher Stat3 binding on the promoter of eIF4e in Lepr iPSCs leads to higher protein synthesis in these cell types as compared to control iPSCs. Finally, point mutation corrected Lepr iPSCs using CRISPR/Cas9 gene editing method showed recovered pluripotency, metabolic and protein synthesis pathways. In conclusion, we have shown that Lepr signaling is involved in the regulation of the metabolic properties and key developmental pathways in MEFs and stemness of pluripotent stem cells. Disruption of Lepr signaling has been shown to involve in the pathophysiology of various diseases including obesity and diabetes. The generated MEFs and iPSCs in this present study provide valuable tools to explore the role of Lepr in the progression of obesity, diabetes and metabolic abnormalities, and to find the putative targets of Lepr signaling during the development of these diseases.

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Leptin Receptor Ablation in Anterior Pituitary Somatotropes Reveals Broad Transcriptomic Changes and Sex-Specific Signaling Pathways

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