Expression profile of serotonin4 (5-HT4) receptors in adrenocortical aldosterone-producing adenomas

Dorthe Cartier (1, 2) , Sylvie Jégou (1, 2) , Françoise Parmentier (3) , Isabelle Lihrmann (1, 2) , Estelle Louiset (1, 2) , Jean-Marc Kuhn (1, 2) , Christian Bastard (3) , Pierre-François Plouin (4, 5) , Michel Godin (6) , Hubert Vaudry (1, 2) , Hervé Lefebvre (1, 2)

1 Neuroendocrinologie cellulaire et moléculaire
2 IFRMP 23 - Institut Fédératif de Recherches Multidisciplinaires sur les Peptides
3 CLCC Henri Becquerel - Centre de Lutte Contre le Cancer Henri Becquerel Normandie Rouen
4 HEGP - Hôpital Européen Georges Pompidou [APHP]
5 UFR Médecine UPCité - UFR Médecine [Santé] - Université Paris Cité
6 CHU Rouen

Objective: We aimed to investigate the expression profile of serotonin4 (5-HT4) receptors in adrenocortical aldosterone-producing adenoma (APA) tissues in comparison with normal adrenal cortex. Design and methods: Total 5-HT4 receptor mRNAs were quantified by real-time quantitative polymerase chain reaction (PCR) assay, and the mRNAs encoding the 5-HT4 receptor isoforms were characterized by reverse transcription (RT)–PCR in seven normal adrenal cortices and 11 APA tissues. The distribution of 5-HT4 receptor mRNAs was investigated by in situ hybridization in both normal adrenal and APA tissues, and the presence of 5-HT in APA tissues was studied by immunohistochemistry. Results: Real-time PCR analysis revealed that 5-HT4 receptor mRNA expression was 4.7–47 times higher in APA tissues than in normal glands. In situ hybridization studies showed that 5-HT4 receptor mRNAs were expressed in both zona glomerulosa and zona fasciculata/reticularis of the normal cortex and in groups of APA steroidogenic cells disseminated in the tumor tissues. Characterization of 5-HT4 receptor splice variants by RT–PCR revealed different profiles of expression in APAs versus normal adrenals. Isoforms (a) and (b) were not expressed in any APA but were present in the majority of normal adrenocortical tissues. Conversely, isoform (d) was expressed in 5/11 APAs but only in 1/7 adrenals. Immunohistochemical studies revealed the presence of 5-HT-immunoreactivity in both mast cells and clusters of steroidogenic cells in APA tissues. Conclusion: Our results show overexpression and different splicing of the 5-HT4 receptor in APA tissues in comparison with normal adrenocortical tissue. They also demonstrate the presence of 5-HT in both mast cells and tumor steroidogenic cells, providing evidence for a possible autocrine/paracrine activation of aldosterone secretion within adenoma tissues.

Domaines: Sciences du Vivant [q-bio]; Biochimie, Biologie Moléculaire; Organisation et fonctions cellulaires [q-bio.SC]

Dorthe Cartier, Sylvie Jégou, Françoise Parmentier, Isabelle Lihrmann, Estelle Louiset, et al.. Expression profile of serotonin4 (5-HT4) receptors in adrenocortical aldosterone-producing adenomas. European Journal of Endocrinology, 2005, 153 (6), pp.939-947. ⟨10.1530/eje.1.02051⟩. ⟨hal-02427128⟩