11β-Hydroxysteroid Dehydrogenase Type 1 within Osteoclasts Mediates the Bone Protective Properties of Therapeutic Corticosteroids in Chronic Inflammation

Therapeutic glucocorticoids (GCs) are powerful anti-inflammatory tools in the management of chronic inflammatory diseases such as rheumatoid arthritis (RA). However, their actions on bone in this context are complex. The enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) is a mediator of the anti-inflammatory actions of therapeutic glucocorticoids (GCs) in vivo. In this study we delineate the role of 11β-HSD1 in the effects of GC on bone during inflammatory polyarthritis. Its function was assessed in bone biopsies from patients with RA and osteoarthritis, and in primary osteoblasts and osteoclasts. Bone metabolism was assessed in the TNF-tg model of polyarthritis treated with oral GC (corticosterone), in animals with global (TNF-tg11βKO), mesenchymal (including osteoblast) (TNF-tg11βflx/tw2cre) and myeloid (including osteoclast) (TNF-tg11βflx/LysMcre) deletion. Bone parameters were assessed by micro-CT, static histomorphometry and serum metabolism markers. We observed a marked increase in 11β-HSD1 activity in bone in RA relative to osteoarthritis bone, whilst the pro-inflammatory cytokine TNFα upregulated 11β-HSD1 within osteoblasts and osteoclasts. In osteoclasts, 11β-HSD1 mediated the suppression of bone resorption by GCs. Whilst corticosterone prevented the inflammatory loss of trabecular bone in TNF-tg animals, counterparts with global deletion of 11β-HSD1 were resistant to these protective actions, characterised by increased osteoclastic bone resorption. Targeted deletion of 11β-HSD1 within osteoclasts and myeloid derived cells partially reproduced the GC resistant phenotype. These data reveal the critical role of 11β-HSD1 within bone and osteoclasts in mediating the suppression of inflammatory bone loss in response to therapeutic GCs in chronic inflammatory disease.

ccfDNA analysis for the classification of adrenocortical adenomas

BACKGROUND

Somatic alterations are commonly observed in adrenocortical adenomas including cortisol-producing (CPA) [overt Cushing syndrome (CS) or mild autonomous cortisol secretion (MACS)], aldosterone-producing (APA), and non-functioning (NFAT) tumors. We tested whether somatic variants could be detected in circulating cell-free DNA (ccfDNA) from patients with adenomas and potentially contribute to management strategies.

MATERIALS AND METHODS

We investigated 44 patients (17 CPA-MACS, 9 CPA-CS, 12 APA, and 6 NFAT). 23 healthy subjects (HS) served as controls. ccfDNA was extracted from blood samples and quantified with fluorimeter. Tumor DNA (T-DNA) was isolated from paraffin embedded tissue in 17/44 cases. Matched ccfDNA/T-DNA were sequenced using a customized panel including 32 genes. Leucocyte DNA was used to filter out germline variants.

RESULTS

Patients with adenomas had higher total ccfDNA concentrations than HS [median 0.12 (IQR 0.05-0.19) vs. 0.05 (0.00-0.08) ng/µl, P < 0.001], with CPA-CS showing the highest ccfDNA levels [0.18 (0.05-0.47) ng/µl]. Within T-DNA, somatic variants were identified in 53% of adenomas: PRKACA in 2/7 CPA-CS, CTNNB1 in 3/5 CPA-MACS and 1/7 CPA-CS, KCNJ5 in 2/5 APA and CACNA1D in 1/5 APA. Somatic mutations were not detected in any of the investigated ccfDNA samples.

CONCLUSIONS

Total ccfDNA concentrations are higher in patients with CPA-CS. Despite the presence of somatic variants in half of tumor samples, we did not detect any at ccfDNA level. Therefore, this approach appears ineffective for pre-operative detection of genetic alterations.

Vamorolone: a novel metabolism resistant steroid that suppresses joint destruction in chronic polyarthritis with reduced systemic side effects

OBJECTIVES

Vamorolone, a dissociated steroidal compound with reduced side effects, offers a promising alternative to traditional glucocorticoids for inflammatory diseases. Unlike conventional glucocorticoids, vamorolone lacks the hydroxyl or ketone groups required for metabolism by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), a key enzyme that modulates glucocorticoid activity. This study investigates vamorolone's resistance to 11β-HSD1 metabolism and assesses its therapeutic efficacy in the murine tumour necros factor-alpha-overexpressing (TNFtg) model of polyarthritis.

METHODS

11β-HSD1 metabolism and action were examined in Hs68 and primary leucocyte culture. Vamorolone 20 mg/kg/day, prednisolone (standard of care) or vehicle were administered by gavage to TNFtg or TNFtg 11β-HSD1 knock-out (TNFtg11BKOKO) animals. Body weight and disease severity were scored daily, and markers of inflammation, joint destruction and side effects assessed at day 56 of age.

RESULTS

Vamorolone was entirely resistant to 11β-HSD1 metabolism in vitro. Vamorolone demonstrated comparable anti-inflammatory actions in TNFtg mice, with a comparable reduction in joint inflammation, serum interleukin-6 (IL-6) and synovitis relative to prednisolone. However, vamorolone-treated mice did not experience typical glucocorticoid side effects, including adrenal atrophy, body weight reduction, muscle wasting or inhibition of anabolic bone metabolism. These benefits persisted in 11β-HSD1 knockout mice, indicating that the efficacy of vamorolone is largely independent of 11β-HSD1 metabolism.

CONCLUSION

The findings suggest that at the effective anti-inflammatory dose examined in this study, vamorolone possesses a reduced profile of deleterious systemic effects relative to prednisolone. Whilst highlighting its potential for broader clinical application in inflammatory conditions, it remains unclear whether these side effects would remain mild at markedly higher doses.

Inflammation dynamically regulates steroid hormone metabolism and action within macrophages in rheumatoid arthritis

RATIONALE

In inflammatory diseases such as rheumatoid arthritis (RA), steroid metabolism is a central component mediating the actions of immuno-modulatory glucocorticoids and sex steroids. However, the regulation and function of cellular steroid metabolism within key leukocyte populations such as macrophages remain poorly defined. In this study, the inflammatory regulation of global steroid metabolism was assessed in RA macrophages.

METHODS

Bulk RNA-seq data from RA synovial macrophages was used to assess transcripts encoding key enzymes in steroid metabolism and signalling. Changes in metabolism were assessed in synovial fluids, correlated to measures of disease activity and functionally validated in primary macrophage cultures.

RESULTS

RNA-seq revealed a unique pattern of differentially expressed genes, including changes in genes encoding the enzymes 11β-HSD1, SRD5A1, AKR1C2 and AKR1C3. These correlated with disease activity, favouring increased glucocorticoid and androgen levels. Synovial fluid 11β-HSD1 activity correlated with local inflammatory mediators (TNFα, IL-6, IL-17), whilst 11β-HSD1, SRD5A1 and AKR1C3 activity correlated with systemic measures of disease and patient pain (ESR, DAS28 ESR, global disease activity). Changes in enzyme activity were evident in inflammatory activated macrophages in vitro and revealed a novel androgen activating role for 11β-HSD1. Together, increased glucocorticoids and androgens were able to suppress inflammation in macrophages and fibroblast-like-synoviocytes.

CONCLUSIONS

This study underscores the significant increase in androgen and glucocorticoid activation within inflammatory polarized macrophages of the synovium, contributing to local suppression of inflammation. The diminished profile of inactive steroid precursors in postmenopausal women may contribute to disturbances in this process, leading to increased disease incidence and severity.

Identification of anti-resorptive GPCRs by high-content imaging in human osteoclasts

Osteoporosis diagnoses are increasing in the ageing population, and although some treatments exist, these have several disadvantages, highlighting the need to identify new drug targets. G protein-coupled receptors (GPCRs) are transmembrane proteins whose surface expression and extracellular activation make them desirable drug targets. Our previous studies have identified 144 GPCR genes to be expressed in primary human osteoclasts, which could provide novel drug targets. The development of high-throughput assays to assess osteoclast activity would improve the efficiency at which we could assess the effect of GPCR activation on human bone cells and could be utilised for future compound screening. Here, we assessed the utility of a high-content imaging (HCI) assay that measured cytoplasmic-to-nuclear translocation of the nuclear factor of activated T cells-1 (NFATc1), a transcription factor that is essential for osteoclast differentiation, and resorptive activity. We first demonstrated that the HCI assay detected changes in NFATc1 nuclear translocation in human primary osteoclasts using GIPR as a positive control, and then developed an automated analysis platform to assess NFATc1 in nuclei in an efficient and unbiased manner. We assessed six GPCRs simultaneously and identified four receptors (FFAR2, FFAR4, FPR1 and GPR35) that reduced osteoclast activity. Bone resorption assays and measurements of TRAP activity verified that activation of these GPCRs reduced osteoclast activity, and that receptor-specific antagonists prevented these effects. These studies demonstrate that HCI of NFATc1 can accurately assess osteoclast activity in human cells, reducing observer bias and increasing efficiency of target detection for future osteoclast-targeted osteoporosis therapies.

POS0056 GLOBAL STEROID METABOLISM IN MACROPHAGES: SHAPING INFLAMMATORY FUNCTION AND DISEASE ACTIVITY IN RHEUMATOID ARTHRITIS

Background

Macrophages are key drivers of joint destruction and disease pathophysiology in rheumatoid arthritis (RA), where their inflammatory function is influenced by steroid hormones such as androgens and glucocorticoids (GCs). Local bioavailability of these steroids is determined by both systemic adrenal/gonadal synthesis and local metabolism in peripheral target tissues. The inflammatory regulation and function of steroid hormone metabolism by key rate limiting enzymes in chronic inflammatory diseases such as RA remain poorly defined and could present new therapeutic targets.

Objectives

Characterise regulation of global steroid metabolism in macrophages in RA and determine its contribution to androgen and GC availability, macrophage function and disease activity.

Methods

Bulk and single cell RNA-sequencing of FACS-sorted macrophages were analysed using previously published datasets from RA patients (27 female, 8 male)(1, 2). Gene expression of rate limiting steroid metabolism enzymes were assessed in macrophages and their subsets and correlated to clinical parameters of disease activity. Primary human monocyte-derived macrophages were polarised to non-inflammatory (M-CSF 20ng/ml) and inflammatory activated (M-CSF 20ng/ml, IFNγ 20ng/ml, TNFα 10ng/ml) subsets and treated with active or inactive metabolites of GCs (cortisol/cortisone 100nmol/l) and androgens (androstenedione/testosterone/DHEA 100nmol/l; DHT 10nmol/l). Metabolism and functional effects were assessed in primary cultures and RA synovial fluids by liquid chromatography mass spectrometry, RT-qPCR and ELISA.

Results

Significant differentially expressed genes (DEGs) were identified in the GC and androgen metabolism pathways in synovial macrophages when stratified for high and low disease activity by DAS28-CRP. Expression of the GC-activating enzyme HSD11B1 and androgen activating enzyme SRD5A1 were significantly increased and positively correlated with disease severity. The androgen activating enzyme AKR1C3 was significantly suppressed and negatively correlated with disease severity. SRD5A1 and HSD11B1 expression were localised to S100A12pos and SPP1pos subsets associated with active RA, whilst AKR1C3 was primarily expressed by MerTKposTREM2high subsets associated with RA remission. Inflammatory activation of primary macrophages decreased AKR1C3, and increased HSD11B1 and SRD5A1 expression. This resulted in a shift in intracrine production of active GCs and androgens favouring increased levels of the active GC cortisol and the potent androgen DHT. The resulting changes in steroid ratios in inflammatory activated macrophages resulted in lower expression and release of the pro-inflammatory mediators TNFα, IL6 and IL12 indicating functional significance. In vivo, metabolic changes favouring increased GC activation and reduced androgen activation correlated with disease severity determined by DAS28-CRP.

Conclusion

We have shown for the first time a role for macrophages and their tissue subsets in the inflammatory metabolism and activation of GCs and androgens in RA, which influence macrophage function and disease activity. Targeting these key metabolic pathways represents a novel route to modifying and suppressing disease activity and joint destruction in chronic polyarthritis.

References

[1]Zhang F, Wei K, Slowikowski K, Fonseka CY, Rao DA, Kelly S, et al. Defining inflammatory cell states in rheumatoid arthritis joint synovial tissues by integrating single-cell transcriptomics and mass cytometry. Nature Immunology. 2019;20(7):928-+.

[2]Alivernini S, MacDonald L, Elmesmari A, Finlay S, Tolusso B, Gigante MR, et al. Distinct synovial tissue macrophage subsets regulate inflammation and remission in rheumatoid arthritis. Nature Medicine. 2020;26(8):1295-+.

Acknowledgements

This research was funded by the Wellcome Trust (ref: 215243/Z/19/Z)

Disclosure of Interests

None declared

Structured Polymers Enable the Sustained Delivery of Glucocorticoids within the Intra-Articular Space

Intra-articular glucocorticoid injections are effective in controlling inflammation and pain in arthritides but restricted by short duration of action and risk of joint degeneration. Controlled drug release using biocompatible hydrogels offers a unique solution, but limitations of in situ gelation restrict their application. Gellan sheared hydrogels (GSHs) retain the advantages of hydrogels, however their unique microstructures lend themselves to intra-articular application - capable of shear thinning under force but restructuring at rest to enhance residence. This study examined GSHs for extended intra-articular glucocorticoid delivery of prednisolone (10 mg mL-1); demonstrating links between material mechanics, steroid release, and preclinical assessment of efficacy in synoviocyte culture and transgenic(TNF)197Gkl (TNFtg) murine model of arthritis. GSHs demonstrated sustained release, with typical Fickian profiles over 18 days. Moreover, systems showed good stability under extended culture, with inherent cell-compatibility and suppression of inflammatory synoviocyte activation. In TNFtg animals, GSHs suppressed synovitis (70.08%, p < 0.05), pannus formation (45.01%, p < 0.05), and increased articular cartilage (82.23%, p < 0.05) relative to vehicle controls. The extended profile of steroid release from injectable GSH formulations holds promise in the treatment and management of inflammatory arthritides such as rheumatoid and osteoarthritis, representing a step-change in intra-articular drug delivery to suppress long-term joint inflammation.