S.Verouti1,2,3 · G. Aeschlimann1 · Q. Wang4 · D. Ancin Del Olmo1 · A. C. Peyter5 · S. Menétrey5 ·D.V. Winter6 · A. Odermatt6 · D. Pearce7 · E. Hummler1,2 · P. E. Vanderriele1,2
Received: 30 April 2024 / Revised: 22 August 2024 / Accepted: 23 August 2024 / Published online: 10 September 2024 © The Author(s) 2024
* P. E. Vanderriele 该Email地址已收到反垃圾邮件插件保护。要显示它您需要在浏览器中启用JavaScript。
1 Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
2 National Center of Competence in Research, Kidney.CH, Lausanne, Switzerland
3 Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
4 Division of Nephrology and Hypertension, Lausanne University Hospital (CHUV), Lausanne, Switzerland
5 Neonatal Research Laboratory, Clinic of Neonatology, Department Woman-Mother-Child, Lausanne University Hospital (CHUV) and University of Lausanne, Lausanne, Switzerland
6 Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
7 Department of Medicine and Cellular & Molecular Pharmacology, University of California, San Francisco, USA
Abstract
In humans, glucocorticoid resistance is attributed to mutations in the glucocorticoid receptor (GR). Most of these mutations result in decreased ligand binding, transactivation, and/or translocation, albeit with normal protein abundances. However, there is no clear genotype‒phenotype relationship between the severity or age at disease presentation and the degree of functional loss of the receptor. Previously, we documented that a GR+/− rat line developed clinical features of glucocorticoid resistance, namely, hypercortisolemia, adrenal hyperplasia, and salt-sensitive hypertension. In this study, we analyzed the GR+/em4 rat model heterozygously mutant for the deletion of exon 3, which encompasses the second zinc finger, including the domains of DNA binding, dimerization, and nuclear localization signals. On a standard diet, mutant rats exhibited a trend toward increased corticosterone levels and a normal systolic blood pressure and heart rate but presented with adrenal hyperplasia. They exhibited increased adrenal soluble epoxide hydroxylase (sEH), favoring an increase in less active poly unsaturated fatty acids. Indeed, a significant increase in nonactive omega-3 and omega-6 polyunsaturated fatty acids, such as 5(6)-DiHETrE or 9(10)-DiHOME, was observed with advanced age (10 versus 5 weeks old) and following a switch to a high-salt diet accompanied by salt-sensitive hypertension. In thoracic aortas, a reduced soluble epoxide hydrolase (sEH) protein abundance resulted in altered vascular reactivity upon a standard diet, which was blunted upon a high-salt diet. In conclusion, mutations in the GR affecting the ligand-binding domain as well as the dimerization domain resulted in deregu lated GR signaling, favoring salt-sensitive hypertension in the absence of obvious mineralocorticoid excess.
Keywords Adrenal gland hyperplasia · Hypertension · Glucocorticoid receptor · Soluble epoxide hydrolase · Chrousos syndrome
Abbreviations
ACTH Adrenocorticotropic hormone DiHETrE Dihydroxyeicosatrienoic acid DiHOME Dihydroxy-9Z-octadecenoic acid EET Epoxyeicosatrienoic acid EpETrE Epoxyeicosatrienoic acid GR Glucocorticoid receptor HETE Hydroxyeicosatetraenoic acid KODE Ketooctadecenoic acid sEH Soluble epoxide hydrolase
◂Fig.1 GR+/em4 rats presented adrenal hyperplasia of the cortex and the medulla accompanied by a trend toward an increase in the plasma glucocorticoid concentration under standard diet. A Scheme of the wild-type (GR+, upper panel) and the mutated GRem2 (middle) and GRem4 (lower panel) structure of the GR. B Representation of the zinc finger domain of the GR with the deleted amino acids in red. C Rep resentative macroscopic images (scale bar, 1 mm) and D hematoxy lin/eosin-stained sections of whole adrenal glands (left panels; scale bar, 1 mm) and cortex (right panels; scale bar, 300 µm) from 3- to 4-week-old male GR+/+ and GR+/em4 rats (n=3) fed a standard salt diet; zf, zona fasciculata; zg, zona glomerulosa. E Measurement of the adrenal weight/body weight ratio (GR+/+, n=12; GR+/em4, n=14) and F cortex (left) and medulla (right panel) size (GR+/+ (n=3) and GR+/em4 (n=4)). G Determination of plasma concentrations of the glucocorticoids corticosterone, 11-dehydrocorticosterone and the corticosterone/11-dehydrocorticosterone ratio and H the mineralo corticoid aldosterone and its precursor 11-deoxycorticosterone in the morning (7–8 am) and afternoon (6–7 pm) of GR+/+ and GR.+/em4 (n=4 – 16) rats. The size measurements were evaluated using QuPath (vO.4.4), and the plasma concentrations were evaluated by two-way ANOVA and subsequently compared with an unpaired two tailed t test with Welch’s correction. The values are presented as the mean±SEMs. Differences were assessed at *P<0.05 and **P<0.01
Introduction
Hypertension is the leading cause of cardiovascular disease and one of the major causes of premature death world wide [30]. Its development is influenced by several fac tors, including genetic background, obesity, and excess salt intake [34] ranging from 8 to 10 g daily [2]. Salt-sensitive hypertension is a common type of high blood pressure that is exacerbated by a high-salt diet and affects approximately 30% of healthy humans [2] and 50% of individuals with hypertension [41]. Several pathways adjust salt excretion to match changes in dietary salt intake in the kidney. Gitelman patients show renal salt wasting due to inactivating muta tions of the SLC12A3 gene encoding the thiazide-sensi tive sodium chloride co-transporter NCC, whereas Liddle patients retain renal sodium due to mutation in the SCNN1β and SCNN1γ genes encoding the b- and g-subunit of ENaC [3, 37]. Furthermore, an implication of the vascular, the sympathetic nervous, the gastrointestinal, and the immune system and the skin was demonstrated as well [10]. Evi dence of the heritability of salt sensitivity was documented, and allelic variants of candidate genes not only affect the renal sodium transport like the angiotensin II type 1 recep tor, the 11β-hydroxysteroid dehydrogenase (11βHSD), or the chloride voltage-gated channel Ka (CLCNKA) but also vascular reactivity like the solute carrier family 24 member 3 (SLC24A3) or the endothelin receptor type B (ENDRB) (for review, see [32]). Several rodent models were used to study salt-sensitive hypertension like Dahl salt-sensitive rats, DOCA-salt-induced mice, or genetically engineered mice mutant for the 11βHSD2 or the βENaC subunit genes (for review, see [7, 32]). Additionally, sex-specific salt sensitiv ity was reported following high-salt diet in female Balb/c mice resulting in impaired endothelium-dependent vasodilation [12] and in male C57Bl/6J mice exhibiting sympathetic overactivity without renal sodium retention [47]. Following norepinephrine or isoproterenol treatment, C57Bl/6J mice exhibited NCC-mediated sodium retention and salt-sensi tive hypertension. In these mice, increased glucocorticoid receptor binding was due to b-adrenergic receptor stimula tion suggesting a role for the development of salt-induced hypertension [36]. There is increasing evidence that GR signaling is involved in salt-sensitive hypertension. Glucocorticoid excess in Cushing syndrome or glucocorticoid resist ance in certain GR mutations induced hypertension and affected renal sodium retention [21]. Approximately 50% of patients with hypercorticolism and GR muta tions exhibit hypertension (for review, see [55]). When kept on a high-salt diet, mice with reduced GR expres sion showed salt sensitivity and sustained hypertension that was attributed to increased mineralocorticoid recep tor activation [24]. Similarly, rats with a mutation within the second zinc finger domain of the GR (Fig. 1A; GR+/ em2 [52]) exhibited higher plasma corticosterone levels although salt-sensitive hypertension was only provoked in combination with high salt intake. These rats carried an out-of-frame mutation of the DNA-binding domain of the GR that resulted in an early Stop codon (GR+/em2) and thus represents a null allele (Figure S1A, B [52];). It has been furthermore reported that high salt intake activated the HPA axis, amplified the stress response, and altered glucocorticoid responsiveness in mice [6] indicating an interplay between salt intake, plasma cortisol/corticoster one, and tissue sensitivity to glucocorticoids. Excess glucocorticoids stimulate renal sodium trans port and can thus mediate mineralocorticoid-like effects although both receptors have distinct but also overlapping physiological functions (for review, see [55]). A recent study proposed that the GR is required for efficient aldoster one-induced transcription via the mineralocorticoid recep tor [25, 59]. In line with these results, it has been dem onstrated that mice with reduced global expression of GR (GR βgeo/+) exhibit glucocorticoid resistance with increased plasma corticosterone levels and high-salt-induced hyper tension, suggesting adaptive failure of the renal vasculature and tubules [24]. To decipher the role of renal GR in salt sensitive hypertension, a nephron tubule-specific mouse GR knockout was generated that overall maintained the Na+ and K+ balance independent of the salt diet [4]. These mice did not present hypercorticosteronemia, and on a high-salt diet, their systolic blood pressure was not different from that of the controls, although these mutant mice showed a significant increase in diastolic blood pressure. This find ing suggested that circulating plasma corticosteroids are involved in sodium homeostasis [4].
