Natriuretic peptide expression and function in GH3 somatolactotropes and feline somatotrope pituitary tumors

Mirczuk, Samantha; Scudder, Christopher; Read, Jordan; Crossley, Victoria; Regan, Jacob; Richardson, Karen; Simbi, Bigboy; Mcardle, Craig; Church, David; Fenn, Joseph; Kenny, Patrick; Volk, Holger; Wheeler-Jones, Caroline; Korbonits, Márta; Niessen, Stijn; Mcgonnell, Imelda; Fowkes, Robert

Abstract

Patients harbouring mutations in genes encoding C-type natriuretic peptide (CNP; NPPC) or its receptor guanylyl cyclase B (GC-B, NPR2) suffer from severe growth phenotypes; loss-of-function mutations cause achondroplasia, whereas gain-of-function mutations cause skeletal overgrowth. Although most of the effects of CNP/GC-B on growth are mediated directly on bone, evidence suggests the natriuretic peptides may also affect anterior pituitary control of growth. Our previous studies described the expression of NPPC and NPR2 in a range of human pituitary tumours, normal human pituitary, and normal fetal human pituitary. However, the natriuretic peptide system in somatotropes has not been extensively explored. Here, we examine the expression and function of the CNP/GC-B system in rat GH3 somatolactotrope cell line and pituitary tumours from a cohort of feline hypersomatotropism (HST; acromegaly) patients. Using multiplex RT-qPCR, all three natriuretic peptides and their receptors were detected in GH3 cells. The expression of Nppc was significantly enhanced following treatment with either 100nM TRH or 10µM forskolin, yet only Npr1 expression was sensitive to forskolin stimulation; the effects of forskolin and TRH on Nppc expression were PKA- and MAPK-dependent, respectively. CNP stimulation of GH3 somatolactotropes significantly inhibited Esr1, Insr and Lepr expression, but dramatically enhanced cFos expression at the same time point. Estrogen treatment significantly enhanced expression of Nppa, Nppc, Npr1 and Npr2 in GH3 somatolactotropes, but inhibited CNP-stimulated cGMP accumulation. Finally, transcripts for all three natriuretic peptides and receptors were expressed in feline pituitary tumours from patients with HST. NPPC expression was negatively correlated with pituitary tumour volume and SSTR5 expression, but positively correlated with D2R and GHR expression. Collectively, these data provide mechanisms that control expression and function of CNP in somatolactotrope cells, and identify putative transcriptional targets for CNP action in somatotropes.

Citation

Mirczuk, S., Scudder, C., Read, J., Crossley, V., Regan, J., Richardson, K., …Fowkes, R. (2021). Natriuretic peptide expression and function in GH3 somatolactotropes and feline somatotrope pituitary tumors. International Journal of Molecular Sciences, -. https://doi.org/10.3390/ijms22031076

• Journal Article Type: Article
• Acceptance Date: Jan 20, 2021
• Online Publication Date: Jan 22, 2021
• Publication Date: Jan 22, 2021
• Deposit Date: Dec 26, 2020
• Publicly Available Date: Feb 22, 2021
• Journal: International Journal of Molecular Sciences
• Print ISSN: 1661-6596
• Publisher: MDPI
• Peer Reviewed: Peer Reviewed
• Pages: -
• DOI: https://doi.org/10.3390/ijms22031076
• Keywords: CNP; multiplex RT-qPCR; pituitary; somatotrope; acromegaly; feline
• Public URL: https://rvc-repository.worktribe.com/output/1442713
• Publisher URL: https://www.mdpi.com/1422-0067/22/3/1076