Molecular mechanisms of glucocorticoid resistance

TRIM24 promotes T-cell lymphoma development and glucocorticoid resistance via FUS-mediated phase separation of the glucocorticoid receptor

T-cell lymphoma (TCL) is an aggressive malignancy with poor therapeutic outcomes, where glucocorticoid (GC) resistance remains a major challenge. Here, we identify TRIM24 as a critical regulator of GC receptor (GR) activity and a potential therapeutic target in TCL. TRIM24 deficiency delays TCL progression in murine models, suppresses cell proliferation, and enhances GC sensitivity by restoring GR transcriptional activity, as evidenced by transcriptomic and chromatin profiling. Mechanistically, TRIM24 interacts with Fused In Sarcoma (FUS) and promotes its liquid-liquid phase separation (LLPS) with GR, leading to impaired GR activity and heightened GC resistance. Moreover, TRIM24 is overexpressed in peripheral T-cell lymphoma (PTCL) samples, correlating with suppressed GR signaling and poor therapeutic response. These findings uncover an unrecognized "double-check" mechanism in which TRIM24 regulates nuclear GR function through FUS-facilitated LLPS. Importantly, targeting TRIM24 may provide a novel therapeutic strategy not only for overcoming GC resistance in TCL but also for addressing broader GR-dependent diseases.

A novel nonsense mutation of the glucocorticoid receptor gene causing glucocorticoid resistance with infertility

PURPOSE

Chrousos syndrome is a rare disease mainly caused by inactivated mutations in the NR3C1 gene, which encodes the human glucocorticoid receptor (GR). We reported a male patient of Chrousos syndrome, who had a novel nonsense mutation (c.1839T > A, p. Tyr613Ter) in NR3C1 and presented with oligospermic and infertility but without other typical clinical manifestation. The aim of this study is to explore the molecular mechanisms that cause the unique clinical manifestations in this patient.

METHODS

Mutant plasmids were transfected to HEK293T and HeLa cells to evaluate glucocorticoid sensitivity and GR expression. Proteomic and further cellular experiments were used to illustrate the mechanism of GR expression change induced by mutation.

RESULTS

The mutation causes the deletion of the ligand-binding region of the GR (GR Y613*). Compared with GR wild type (GR WT), GR Y613* had a decreased affinity with dexamethasone, reduced nuclear translocation and decreased transactivation of the glucocorticoid response gene mouse mammary tumor virus promoter. GR Y613* caused decreased protein but unchanged gene expression. E3 ligase STUB1 was identified to regulate ubiquitin-proteasome degradation of GR Y613*. Compared with other human tissues and cell types, expression of STUB1 in testis and Sertoli cells was low.

CONCLUSIONS

GR Y613* causes reduced sensitivity to glucocorticoids. STUB1 promotes ubiquitination and degradation of GR Y613*. Low expression of STUB1 in human testis compared with other tissue might cause accumulation of GR Y613*, as a potential explanation of the infertility of Chrousos syndrome.

The impact of glucocorticoid receptor transactivation on context-dependent cell migration dynamics

The glucocorticoid receptor (GR) plays a significant role in breast cancer cell behaviour, although data on its effects are conflicting. The impact of GR agonist dexamethasone (dex) and antagonist mifepristone (mif) on oestrogen-positive (ER+) and triple-negative (TN) breast cancer cell lines in both 2D and 3D cultures was studied using multiple in vitro functional assays and transcriptome sequencing. GR activation increased cell motility in TN but not in ER + tumour cells, as observed in both collective and single-cell migration tests. Time-lapse analysis showed enhanced motility after 4-6 h in wound healing, despite dex inhibiting migration initially. This inhibition was observed at 2 h in single-cell tracking migration assays. Cell proliferation increased in TN and decreased in ER + cells upon GR activation, reversed by GR antagonist. RNA sequencing revealed dex's impact on cell adhesion and extracellular matrix signalling in TN cells and on DNA replication in ER + cells. Based on data from 1085 human breast cancer specimens, GR pathway expression correlated with migratory, extracellular matrix, and angiogenesis gene signatures. Additionally, higher expression of GR and increased GR signature were observed in fast-migrating cells compared to slow-migrating ones. Positive correlation between the GR signature and migration signature at the single-cell level indicated an association between GR activity and cell migration. For the first time, we assessed altered time-lapse migration dynamics in TN breast cancer cells, potentially contributing to cancer progression and prognosis, highlighting that the effects of dexamethasone on breast cancer cell migration are influenced by ER status and treatment duration.

CGG repeats in the human FMR1 gene regulate mRNA localization and cellular stress in developing neurons

The human genome has many short tandem repeats, yet the normal functions of these repeats are unclear. The 5' untranslated region (UTR) of the fragile X messenger ribonucleoprotein 1 (FMR1) gene contains polymorphic CGG repeats, the length of which has differing effects on FMR1 expression and human health, including the neurodevelopmental disorder fragile X syndrome. We deleted the CGG repeats in the FMR1 gene (0CGG) in human stem cells and examined the effects on differentiated neurons. 0CGG neurons have altered subcellular localization of FMR1 mRNA and protein, and differential expression of cellular stress proteins compared with neurons with normal repeats (31CGG). In addition, 0CGG neurons have altered responses to glucocorticoid receptor (GR) activation, including FMR1 mRNA localization, GR chaperone HSP90α expression, GR localization, and cellular stress protein levels. Therefore, the CGG repeats in the FMR1 gene are important for the homeostatic responses of neurons to stress signals.

Cortisol in metabolic syndrome

Cortisol, a stress hormone, plays a crucial role in regulating metabolic, hemodynamic, inflammatory, and behavioral processes. Its secretion is governed by the hypothalamic-pituitary-adrenal axis. However, prolonged activation of this axis and increased cortisol bioavailability in tissues can result in detrimental metabolic effects. Chronic exposure to excessive cortisol is associated with insulin resistance and visceral obesity, both significant contributors to metabolic syndrome. This review delves into the regulation of the hypothalamic-pituitary-adrenal axis, the molecular mechanisms underlying cortisol synthesis and its actions, as well as the key factors influencing cortisol bioavailability. Furthermore, it provides a summary of available clinical research data on the involvement of cortisol in metabolic syndrome, alongside a discussion on the various biomatrices used for cortisol measurement in clinical settings.

Interactions between MDSCs and the Autonomic Nervous System: Opportunities and Challenges in Cancer Neuroscience

Myeloid-derived suppressor cells (MDSC) are a population of heterogeneous immune cells that are involved in precancerous conditions and neoplasms. The autonomic nervous system (ANS), which is composed of the sympathetic nervous system and the parasympathetic nervous system, is an important component of the tumor microenvironment that responds to changes in the internal and external environment mainly through adrenergic and cholinergic signaling. An abnormal increase of autonomic nerve density has been associated with cancer progression. As we discuss in this review, growing evidence indicates that sympathetic and parasympathetic signals directly affect the expansion, mobilization, and redistribution of MDSCs. Dysregulated autonomic signaling recruits MDSCs to form an immunosuppressive microenvironment in chronically inflamed tissues, resulting in abnormal proliferation and differentiation of adult stem cells. The two components of the ANS may also be responsible for the seemingly contradictory behaviors of MDSCs. Elucidating the underlying mechanisms has the potential to provide more insights into the complex roles of MDSCs in tumor development and lay the foundation for the development of novel MDSC-targeted anticancer strategies.

Presentation and Care for Children with Peripheral Precocious Puberty

Peripheral precocious puberty (PPP) refers to the early onset of sexual maturation that is independent of central nervous system control. The extensive differential diagnosis includes congenital and acquired causes. Presenting features depend on which class of sex steroids is involved, and diagnosis rests on hormonal and, if indicated, imaging and/or genetic studies. Effective treatment exists for nearly all causes of PPP. Ongoing research will advance our therapeutic armamentarium and understanding of the pathophysiologic basis of these conditions.

Diagnosis and management of non-CAH 46,XX disorders/differences in sex development

Prenatal-onset androgen excess leads to abnormal sexual development in 46,XX individuals. This androgen excess can be caused endogenously by the adrenals or gonads or by exposure to exogenous androgens. The most common cause of 46,XX disorders/differences in sex development (DSD) is congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency, comprising >90% of 46,XX DSD cases. Deficiencies of 11β-hydroxylase, 3β-hydroxysteroid dehydrogenase, and P450-oxidoreductase (POR) are rare types of CAH, resulting in 46,XX DSD. In all CAH forms, patients have normal ovarian development. The molecular genetic causes of 46,XX DSD, besides CAH, are uncommon. These etiologies include primary glucocorticoid resistance (PGCR) and aromatase deficiency with normal ovarian development. Additionally, 46,XX gonads can differentiate into testes, causing 46,XX testicular (T) DSD or a coexistence of ovarian and testicular tissue, defined as 46,XX ovotesticular (OT)-DSD. PGCR is caused by inactivating variants in NR3C1, resulting in glucocorticoid insensitivity and the signs of mineralocorticoid and androgen excess. Pathogenic variants in the CYP19A1 gene lead to aromatase deficiency, causing androgen excess. Many genes are involved in the mechanisms of gonadal development, and genes associated with 46,XX T/OT-DSD include translocations of the SRY; copy number variants in NR2F2, NR0B1, SOX3, SOX9, SOX10, and FGF9, and sequence variants in NR5A1, NR2F2, RSPO1, SOX9, WNT2B, WNT4, and WT1. Progress in cytogenetic and molecular genetic techniques has significantly improved our understanding of the etiology of non-CAH 46,XX DSD. Nonetheless, uncertainties about gonadal function and gender outcomes may make the management of these conditions challenging. This review explores the intricate landscape of diagnosing and managing these conditions, shedding light on the unique aspects that distinguish them from other types of DSD.

A teenage girl with altered mental status and paraparesis

A teenage girl presented with fever and altered mental status. MRI showed diffuse leptomeningeal enhancement of the brain and spine. She was diagnosed by a positive cerebrospinal fluid (CSF) culture with tuberculous (TB) meningitis and was started on anti-TB medications and corticosteroids. Her mental status improved, but she was noted to have proximal weakness of the lower extremities. In the course of tapering corticosteroids at week 11 of anti-TB therapy, she became acutely confused and febrile. MRI demonstrated interval development of tuberculomas in the brain and a mass lesion in the thoracic spine causing cord compression. Given the clinical picture was suggestive of a paradoxical reaction, the dose of corticosteroids was increased. Infliximab was added when repeat MRI revealed enlargement of the mass lesion in the spine with worsening cord compression. She was successfully tapered off of corticosteroids. Over several months, the patient's motor function recovered fully, and she returned to ambulating without assistance.

Chromatin accessibility landscape of relapsed pediatric B-lineage acute lymphoblastic leukemia

For around half of the pediatric B-lineage acute lymphoblastic leukemia (B-ALL) patients, the molecular mechanism of relapse remains unclear. To fill this gap in knowledge, here we characterize the chromatin accessibility landscape in pediatric relapsed B-ALL. We observe rewired accessible chromatin regions (ACRs) associated with transcription dysregulation in leukemia cells as compared with normal B-cell progenitors. We show that over a quarter of the ACRs in B-ALL are in quiescent regions with high heterogeneity among B-ALLs. We identify subtype-specific and allele-imbalanced chromatin accessibility by integrating multi-omics data. By characterizing the differential ACRs between diagnosis and relapse in B-ALL, we identify alterations in chromatin accessibility during drug treatment. Further analysis of ACRs associated with relapse free survival leads to the identification of a subgroup of B-ALL which show early relapse. These data provide an advanced and integrative portrait of the importance of chromatin accessibility alterations in tumorigenesis and drug responses.

The role of the oxytocin system in the resilience of patients with breast cancer

Breast cancer is a grave traumatic experience that can profoundly compromise patients' psychological resilience, impacting their overall quality of life. The oxytocin system represents one of the essential neurobiological bases of psychological resilience and plays a critical role in regulating resilience in response to social or traumatic events during adulthood. Oxytocin, through its direct interaction with peripheral or central oxytocin receptors, has been found to have a significant impact on regulating social behavior. However, the precise mechanism by which the activation of peripheral oxytocin receptors leads to improved social is still not completely comprehended and requires additional research. Its activation can modulate psychological resilience by influencing estrogen and its receptors, the hypothalamic-pituitary-adrenal axis, thyroid function, 5-hydroxytryptamine metabolism levels, and arginine pressure release in breast cancer patients. Various interventions, including psychotherapy and behavioral measures, have been employed to improve the psychological resilience of breast cancer patients. The potential effectiveness of such interventions may be underpinned by their ability to modulate oxytocin release levels. This review provides an overview of the oxytocin system and resilience in breast cancer patients and identifies possible future research directions and interventions.

Optimization and Characterization of Novel ALCAM-Targeting Antibody Fragments for Transepithelial Delivery

Activated leukocyte cell adhesion molecule (ALCAM) is a cell adhesion molecule that supports T cell activation, leukocyte migration, and (lymph)angiogenesis and has been shown to contribute to the pathology of various immune-mediated disorders, including asthma and corneal graft rejection. In contrast to monoclonal antibodies (mAbs) targeting ALCAM's T cell expressed binding partner CD6, no ALCAM-targeting mAbs have thus far entered clinical development. This is likely linked with the broad expression of ALCAM on many different cell types, which increases the risk of eliciting unwanted treatment-induced side effects upon systemic mAb application. Targeting ALCAM in surface-exposed tissues, such as the lungs or the cornea, by a topical application could circumvent this issue. Here, we report the development of various stability- and affinity-improved anti-ALCAM mAb fragments with cross-species reactivity towards mouse, rat, monkey, and human ALCAM. Fragments generated in either mono- or bivalent formats potently blocked ALCAM-CD6 interactions in a competition ELISA, but only bivalent fragments efficiently inhibited ALCAM-ALCAM interactions in a leukocyte transmigration assay. The different fragments displayed a clear size-dependence in their ability to penetrate the human corneal epithelium. Furthermore, intranasal delivery of anti-ALCAM fragments reduced leukocyte infiltration in a mouse model of asthma, confirming ALCAM as a target for topical application in the lungs.