β-catenin in adrenal zonation and disease

Hippo Signaling Is Essential for the Maintenance of Zona Glomerulosa Cell Fate in the Murine Adrenal Cortex

Cells of the zona glomerulosa (zG), the outermost zone of the adrenal cortex, secrete aldosterone and transdifferentiate into glucocorticoid-producing cells of the zona fasciculata (zF) during adrenal homeostasis. However, our understanding of the signaling pathways mediating zG cell maintenance or their transdifferentiation into zF cells is incomplete. Hippo is a major pathway that regulates cell proliferation/differentiation during embryogenesis and postnatal tissue homeostasis. Hypothesizing that Hippo signaling could be involved in zG cell maintenance or transdifferentiation, we generated a mouse model in which the two main kinases of the Hippo signaling cascade large tumor suppressor homolog kinases 1/2 (Lats1 and Lats2) are specifically inactivated in zG cells. Here we show that loss of function of Lats1 and Lats2 impairs zG steroidogenesis and leads to zG cell transdifferentiation into cells sharing characteristics with chondroblasts/osteoblasts rather than zF cells. Furthermore, we demonstrate that this phenotype can be rescued by the concomitant inactivation of the transcriptional coactivators Yes-associated protein (Yap) and transcriptional coactivator with PDZ-binding motif (Taz) with Lats1 and Lats2. Finally, we show that expression of a constitutively active form of YAP (YAP5SA) in zG cells does not alter their fate as severely as the loss of Lats1 and Lats2 but leads to adrenal hyperplasia. Together, these findings highlight the critical role of Hippo signaling in maintaining zG cell fate and function and provide key insights into broader mechanisms underlying cellular differentiation.

Therapeutic strategies for adrenocortical carcinoma: integrating genomic insights, molecular targeting, and immunotherapy

Adrenocortical carcinoma (ACC) is an uncommon and highly aggressive cancer originating in the adrenal cortex, characterized by a high likelihood of recurrence and unfavorable survival rates, particularly in the advanced disease stages. This review discusses the complex molecular pathogenesis of ACC, focusing on critical pathways implicated in the tumorigenesis and providing potential targets for therapy: the Wnt/β-catenin signaling pathway, the IGF2/IGF1R axis, and the apoptosis pathway regulated by p53. Current treatment strategies include surgical resection and mitotane, the sole adrenolytic agent approved by the FDA; however, its effects in advanced disease are suboptimal. Cytotoxic chemotherapy combined with mitotane may be applied, but survival benefits are limited so far. In the following review, we outline emerging targeted therapies, such as mTOR inhibitors and tyrosine kinase inhibitors (TKIs), which show favorable preclinical and clinical data, especially in treatment-resistant ACC. We also emphasize the possible role of immune checkpoint inhibitors (ICIs) in the management of ACC, although their effectiveness is still under study. Upcoming trends in treatment involve forms of personalized medicine, where molecular profiling is integrated to identify actionable biomarkers for administered therapies. This review will attempt to provide a comprehensive framework on how recent breakthroughs in the genomics of ACC, coupled with advances in targeted therapies and immunotherapy, can improve management.

Coconut oil reduces steroidogenic enzymes and imbalances estrogen receptors in the adrenal cortex of Mongolian gerbils

This study aims to verify the effects of prolonged ingestion of coconut oil on the adrenal glands of Mongolian gerbils. Mongolian gerbils were used as an experimental model due to the morphological similarity of the adrenal glands to those of primates. Male Mongolian gerbils, 3 months of age, were divided into three experimental groups (n = 12): an intact control group, which received no treatment, a gavage control group, which received 0.1 ml of water daily by gavage, and a coconut oil-treated group, which received 0.1 ml of coconut oil daily for 12 months. The results showed that prolonged consumption of coconut oil caused an increase in cell area and thickness of the zona reticularis and the accumulation of lipid droplets, as well as reducing the amount of steroidogenic enzymes, such as CYP17, 3BHSD, and 17BHSD. It was also observed that the oil increased the expression of estrogen receptor alpha and their isoforms. These alterations allow us to conclude that changes in the lipid diet can cause alterations in the morphophysiology of the adrenal gland and, consequently, impact its functionality.

Analysis of Cancer Stem Cell Markers in Various Histological Subtypes of Adrenocortical Cancer

Adrenocortical cancer (ACC) is a rare malignant neoplasm originating from the adrenal cortex, presenting limited therapeutic options. An avenue for improving therapeutic efficacy may involve a deeper understanding of the role of adrenocortical stem/progenitor cells in the pathogenesis of this disease. Although existing data suggest stem/progenitor characteristics in certain cell populations within ACC, the challenge remains to identify adrenocortical stem cell markers directly involved in its carcinogenesis. In our study, we aimed to identify multipotency markers such as LGR5 and CD90 in various ACC types to confirm their presence and localization. The study included tumor tissue samples from 13 patients with ACC treated at the Endocrinology Research Centre (Moscow, Russia) between 2005 and 2023. We conducted immunohistochemical analyses to identify the aforementioned markers and examined the association between their expression and clinico-morphological parameters. Our pilot study results demonstrate the presence of LGR5- and CD90-positive tumor cells in all samples. Despite the small sample size, we observed statistically significant differences in disease-free survival based on the number of CD90-positive cells. These findings suggest a potential diagnostic, prognostic, and predictive value of cancer stem cell markers, underscoring the need for their further analysis in a larger cohort of patients with ACC.

Evaluating the role of aldosterone synthesis on adrenal cell fate

Hypertension affects one-third of the adult population worldwide, with primary aldosteronism (PA) accounting for at least 5-10% of these cases. The aldosterone synthase enzyme (CYP11B2) plays a pivotal role in PA manifestation, as increased expression of CYP11B2 leads to excess aldosterone synthesis. Physiological expression of CYP11B2 in humans is normally limited to cells of the adrenal zona glomerulosa under tight homeostatic regulation. In PA, however, there are CYP11B2-positive lesions in the adrenal cortex that autonomously secrete aldosterone, highlighting the dysregulation of adrenal cortex zonation and function as a key aspect of PA pathogenesis. Thus, this review aims to summarize the development of the adrenal glands, the key regulators of adrenal cortex homeostasis, and the dysregulation of this homeostasis. It also discusses the development of CYP11B2 inhibitors for therapeutic use in patients with hypertension, as well as the current knowledge of the effects of CYP11B2 inhibition on adrenal cortex homeostasis and cell fate. Understanding the control of adrenal cell fate may offer valuable insights into both the pathogenesis of PA and the development of alternative treatment approaches for PA.

Mild autonomous cortisol secretion: pathophysiology, comorbidities and management approaches

The majority of incidentally discovered adrenal tumours are benign adrenocortical adenomas and the prevalence of adrenocortical adenomas is around 1-7% on cross-sectional abdominal imaging. These can be non-functioning adrenal tumours or they can be associated with autonomous cortisol secretion on a spectrum that ranges from rare clinically overt adrenal Cushing syndrome to the much more prevalent mild autonomous cortisol secretion (MACS) without signs of Cushing syndrome. MACS is diagnosed (based on an abnormal overnight dexamethasone suppression test) in 20-50% of patients with adrenal adenomas. MACS is associated with cardiovascular morbidity, frailty, fragility fractures, decreased quality of life and increased mortality. Management of MACS should be individualized based on patient characteristics and includes adrenalectomy or conservative follow-up with treatment of associated comorbidities. Identifying patients with MACS who are most likely to benefit from adrenalectomy is challenging, as adrenalectomy results in improvement of cardiovascular morbidity in some, but not all, patients with MACS. Of note, diagnosis and management of patients with bilateral MACS is especially challenging. Current gaps in MACS clinical practice include a lack of specific biomarkers diagnostic of MACS-related health outcomes and a paucity of clinical trials demonstrating the efficacy of adrenalectomy on comorbidities associated with MACS. In addition, little evidence exists to demonstrate the efficacy and safety of long-term medical therapy in patients with MACS.

A switch in letters leads to the "creation" of Eszett (ß)-catenin rather than beta (β)-catenin

A simple replacement-most likely due to a linguistic error-of the Greek letter beta (β) by the German letter Eszett (ß), has led to the introduction of an error in a body of literature related to beta (β)-catenin, resulting in the "creation" of a non-existent compound and false positive, Eszett (ß)-catenin. A search on 9 December 2023 in PubMed for ß-catenin and β-catenin revealed 395 and 45,919 results, respectively. The 25 results of ß-catenin published in 2023 were examined in more detail to appreciate the location(s) in each paper where this error had occurred. While the scientific findings of these studies do not seem to be impacted by this error, authors and editors would need to weigh the need or benefit of correcting this error.

In Vivo Formation of Adrenal Organoids in a Novel Porcine Model of Adrenocortical Cell Transplantation

Recognizing the limitations of current therapies for Addison's disease, novel treatments that replicate dynamic physiologic corticosteroid secretion, under control of ACTH, are required. The aim of these experiments was to evaluate the feasibility of adrenocortical cell transplantation (ACT) in a large animal model, adapting methods successfully used for intracutaneous pancreatic islet cell transplantation, using a fully biodegradable temporizing matrix. Autologous porcine ACT was undertaken by bilateral adrenalectomy, cell isolation, culture, and intracutaneous injection into a skin site preprepared using a biodegradable temporizing matrix (BTM) foam. Hydrocortisone support was provided during adrenocortical cell engraftment and weaned as tolerated. Blood adrenocortical hormone concentrations were monitored, and the transplant site was examined at endpoint. Outcome measures included cellular histochemistry, systemic hormone production, and hydrocortisone independence. Transplanted adrenocortical cells showed a capability to survive and proliferate within the intracutaneous site and an ability to self-organize into discrete tissue organoids with features of the normal adrenal histologic architecture. Interpretation of systemic hormone levels was confounded by the identification of accessory adrenals and regenerative cortical tissue within the adrenal bed postmortem. Corticosteroids were unable to be completely ceased. ACT in a large animal model has not previously been attempted, yet it is an important step toward clinical translation. These results demonstrate rhe potential for ACT based on the development of adrenal organoids at the BTM site. However, the inability to achieve clinically relevant systemic hormone production suggests insufficient function, likely attributable to insufficient cells through delivered dose and subsequent proliferation.

Human-like adrenal features in Chinese tree shrews revealed by multi-omics analysis of adrenal cell populations and steroid synthesis

The Chinese tree shrew ( Tupaia belangeri chinensis) has emerged as a promising model for investigating adrenal steroid synthesis, but it is unclear whether the same cells produce steroid hormones and whether their production is regulated in the same way as in humans. Here, we comprehensively mapped the cell types and pathways of steroid metabolism in the adrenal gland of Chinese tree shrews using single-cell RNA sequencing, spatial transcriptome analysis, mass spectrometry, and immunohistochemistry. We compared the transcriptomes of various adrenal cell types across tree shrews, humans, macaques, and mice. Results showed that tree shrew adrenal glands expressed many of the same key enzymes for steroid synthesis as humans, including CYP11B2, CYP11B1, CYB5A, and CHGA. Biochemical analysis confirmed the production of aldosterone, cortisol, and dehydroepiandrosterone but not dehydroepiandrosterone sulfate in the tree shrew adrenal glands. Furthermore, genes in adrenal cell types in tree shrews were correlated with genetic risk factors for polycystic ovary syndrome, primary aldosteronism, hypertension, and related disorders in humans based on genome-wide association studies. Overall, this study suggests that the adrenal glands of Chinese tree shrews may consist of closely related cell populations with functional similarity to those of the human adrenal gland. Our comprehensive results (publicly available at http://gxmujyzmolab.cn:16245/scAGMap/) should facilitate the advancement of this animal model for the investigation of adrenal gland disorders.

Double somatic mutations in CTNNB1 and GNA11 in an aldosterone-producing adenoma

Double somatic mutations in CTNNB1 and GNA11/Q have recently been identified in a small subset of aldosterone-producing adenomas (APAs). As a possible pathogenesis of APA due to these mutations, an association with pregnancy, menopause, or puberty has been proposed. However, because of its rarity, characteristics of APA with these mutations have not been well characterized. A 46-year-old Japanese woman presented with hypertension and hypokalemia. She had two pregnancies in the past but had no history of pregnancy-induced hypertension. She had regular menstrual cycle at presentation and was diagnosed as having primary aldosteronism after endocrinologic examinations. Computed tomography revealed a 2 cm right adrenal mass. Adrenal venous sampling demonstrated excess aldosterone production from the right adrenal gland. She underwent right laparoscopic adrenalectomy. The resected right adrenal tumor was histologically diagnosed as adrenocortical adenoma and subsequent immunohistochemistry (IHC) revealed diffuse immunoreactivity of aldosterone synthase (CYP11B2) and visinin like 1, a marker of the zona glomerulosa (ZG), whereas 11β-hydroxylase, a steroidogenic enzyme for cortisol biosynthesis, was mostly negative. CYP11B2 IHC-guided targeted next-generation sequencing identified somatic CTNNB1 (p.D32Y) and GNA11 (p.Q209H) mutations. Immunofluorescence staining of the tumor also revealed the presence of activated β-catenin, consistent with features of the normal ZG. The expression patterns of steroidogenic enzymes and related proteins indicated ZG features of the tumor cells. PA was clinically and biochemically cured after surgery. In conclusion, our study indicated that CTNNB1 and GNA11-mutated APA has characteristics of the ZG. The disease could occur in adults with no clear association with pregnancy or menopause.

An integrated single-cell analysis of human adrenal cortex development

The adrenal glands synthesize and release essential steroid hormones such as cortisol and aldosterone, but many aspects of human adrenal gland development are not well understood. Here, we combined single-cell and bulk RNA sequencing, spatial transcriptomics, IHC, and micro-focus computed tomography to investigate key aspects of adrenal development in the first 20 weeks of gestation. We demonstrate rapid adrenal growth and vascularization, with more cell division in the outer definitive zone (DZ). Steroidogenic pathways favored androgen synthesis in the central fetal zone, but DZ capacity to synthesize cortisol and aldosterone developed with time. Core transcriptional regulators were identified, with localized expression of HOPX (also known as Hop homeobox/homeobox-only protein) in the DZ. Potential ligand-receptor interactions between mesenchyme and adrenal cortex were seen (e.g., RSPO3/LGR4). Growth-promoting imprinted genes were enriched in the developing cortex (e.g., IGF2, PEG3). These findings reveal aspects of human adrenal development and have clinical implications for understanding primary adrenal insufficiency and related postnatal adrenal disorders, such as adrenal tumor development, steroid disorders, and neonatal stress.

Future directions for adrenal insufficiency: cellular transplantation and genetic therapies

Primary adrenal insufficiency occurs in 1 in 5-7000 adults. Leading aetiologies are autoimmune adrenalitis in adults and congenital adrenal hyperplasia (CAH) in children. Oral replacement of cortisol is lifesaving, but poor quality of life, repeated adrenal crises and dosing uncertainty related to lack of a validated biomarker for glucocorticoid sufficiency, persists. Adrenocortical cell therapy and gene therapy may obviate many of the shortcomings of adrenal hormone replacement. Physiological cortisol secretion regulated by pituitary adrenocorticotropin, could be achieved through allogeneic adrenocortical cell transplantation, production of adrenal-like steroidogenic cells from either stem cells or lineage conversion of differentiated cells, or for CAH, gene therapy to replace or repair a defective gene. The adrenal cortex is a high turnover organ and thus failure to incorporate progenitor cells within a transplant will ultimately result in graft exhaustion. Identification of adrenocortical progenitor cells is equally important in gene therapy where new genetic material must be specifically integrated into the genome of progenitors to ensure a durable effect. Delivery of gene editing machinery and a donor template, allowing targeted correction of the 21-hydroxylase gene, has the potential to achieve this. This review describes advances in adrenal cell transplants and gene therapy that may allow physiological cortisol production for children and adults with primary adrenal insufficiency.

Loss of SUMO-specific protease 2 causes isolated glucocorticoid deficiency by blocking adrenal cortex zonal transdifferentiation in mice

SUMOylation is a dynamic posttranslational modification, that provides fine-tuning of protein function involved in the cellular response to stress, differentiation, and tissue development. In the adrenal cortex, an emblematic endocrine organ that mediates adaptation to physiological demands, the SUMOylation gradient is inversely correlated with the gradient of cellular differentiation raising important questions about its role in functional zonation and the response to stress. Considering that SUMO-specific protease 2 (SENP2), a deSUMOylating enzyme, is upregulated by Adrenocorticotropic Hormone (ACTH)/cAMP-dependent Protein Kinase (PKA) signalling within the zona fasciculata, we generated mice with adrenal-specific Senp2 loss to address these questions. Disruption of SENP2 activity in steroidogenic cells leads to specific hypoplasia of the zona fasciculata, a blunted reponse to ACTH and isolated glucocorticoid deficiency. Mechanistically, overSUMOylation resulting from SENP2 loss shifts the balance between ACTH/PKA and WNT/β-catenin signalling leading to repression of PKA activity and ectopic activation of β-catenin. At the cellular level, this blocks transdifferentiation of β-catenin-positive zona glomerulosa cells into fasciculata cells and sensitises them to premature apoptosis. Our findings indicate that the SUMO pathway is critical for adrenal homeostasis and stress responsiveness.