The rise in expression and activity of 11β-HSD1 in human mesenchymal progenitor cells induces adipogenesis through increased local cortisol synthesis

Study on the mechanism of Shuanghe decoction against steroid-induced osteonecrosis of the femoral head: insights from network pharmacology, metabolomics, and gut microbiota

BACKGROUND

Steroid-induced osteonecrosis of the femoral head (SONFH) is a challenging and debilitating orthopedic condition with a rising incidence in recent years. Shuanghe Decoction (SHD), a traditional Chinese medicine formula, has shown significant efficacy in treating SONFH, though its underlying mechanisms remain unclear.

PURPOSE

This study aims to elucidate the therapeutic effects and potential mechanisms of SHD on SONFH through in vivo experiments, combined with network pharmacology, metabolomics, and gut microbiota analysis.

MATERIALS AND METHODS

Forty male Sprague-Dawley rats (300 ± 20 g) were randomly assigned to four groups: Control, Model, SHD-L, and SHD-H, with 10 rats each. SONFH was induced in all groups except the Control group using lipopolysaccharide and methylprednisolone. The SHD-L and SHD-H groups were treated with Shuanghe decoction at doses of 4.86 g/kg/day and 9.72 g/kg/day, respectively, for eight weeks. Bone morphology, pathological changes, and osteogenic factors were evaluated using Micro-CT, histological staining, and immunohistochemistry. Network pharmacology, metabolomics, and gut microbiota analyses were conducted to explore SHD's mechanisms.

RESULTS

SHD improved bone morphology and increased osteogenic factor expression (RUNX2, OCN, COL-I). Network pharmacology indicated that metabolic pathways play a key role in SHD's therapeutic effects. Metabolomic analysis identified 14 differential metabolites, including 21-hydroxypregnenolone and tyramine, which were restored to normal levels by SHD. Gut microbiota analysis revealed that SHD modulated bacterial abundance, particularly Verrucomicrobia, Allobaculum, and Burkholderiales. A comprehensive network identified two key metabolites (tyramine, 21-hydroxypregnenolone), seven targets (CYP19A1, CYP1A2, CYP1B1, CYP2C9, CYP3A4, MIF, and HSD11B1), two metabolic pathways (tyrosine metabolism, steroid hormone biosynthesis), and four bacterial taxa (Jeotgalicoccus, Clostridium, Corynebacterium, rc4-4) as central to SHD against SONFH.

CONCLUSION

SHD alleviates SONFH by reshaping gut microbiota, reversing metabolic imbalances, and enhancing osteogenesis. Our findings provide novel insights into the pharmacological mechanisms of SHD, laying a foundation for its clinical application in treating SONFH.

Deletion of absent in melanoma-2 (AIM2) drives bone marrow adipogenesis and impairs bone microarchitecture

Absent in melanoma (AIM) 2, a gene induced by interferon, acts as a cytosolic sensor for double-stranded (ds) DNA. It forms the AIM2 inflammasome, producing interleukin (IL)-1β and IL-18. Our previous study demonstrated that mice lacking AIM2 exhibit spontaneous obesity, insulin resistance, and inflammation in adipose tissue. In this study, we aimed to explore the impact of AIM2 gene deletion on the bone marrow microenvironment and bone morphology in adult and aged mice. Utilizing micro-computed tomography (micro-CT), we discovered that female mice lacking AIM2 showed an increase in the total cross-sectional area at 5 months of age, accompanied by an increase in cortical thickness in the mid-diaphysis of the femur at both 5 and 15 months of age. At 15 months, the cortical bone mineral density (BMD) significantly decreased in AIM2 null females compared to wildtype (WT) mice. Trabecular bone volume and BMD at the distal metaphysis of the femur and the lumbar vertebra-4 were also significantly decreased in AIM2 null females. Histological examination of femurs from aged mice demonstrated increased bone marrow adiposity in AIM2 null mice, accompanied by a significant increase in CD45 - /CD31 - /Sca1 + /Pdgfa + adipogenic progenitor cells and a decrease in the ratio of CD45 - /CD31 - /Sca1 - /Pdgfa + osteogenic progenitor cells, as determined by flow cytometry of bone marrow cells. RNAseq analysis of the bone marrow revealed a significant increase in interferon-stimulated genes with Ifi202b as the top-upregulated gene in AIM2 null mice. Our findings suggest that AIM2 deficiency affects bone health by promoting adipogenesis in the bone marrow and inducing a pro-inflammatory environment, thereby contributing to decreased bone mineral density.

Electrospun 11β-HSD1 Inhibitor-Loaded Scaffolds for Accelerating Diabetic Ulcer Healing

Diabetic ulcers (DUs) are a common and severe complication of diabetes, characterized by impaired wound healing due to a complex pathophysiological mechanism. Elevated levels of 11β-hydroxysteroid dehydrogenase type I (11β-HSD1) in wounds have been demonstrated to modulate glucocorticoid activity, leading to delayed skin cell proliferation and restricted angiogenesis, ultimately hindering wound healing. In this study, we propose an electrospun poly(ε-caprolactone) (PCL) nanofiber scaffold doped with the 11β-HSD1 inhibitor BVT2733 (BPs) to prevent 11β-HSD1 activity during the diabetic wound healing process. The electrospun scaffold loaded with BVT2733 is designed to achieve localized inhibition of 11β-HSD1 in DUs. This scaffold exhibited a porous morphology and desirable drug-loading capacity, meeting the requirements for wound coverage and effective delivery of BVT2733 BPs. In vitro studies demonstrated that the sustained release of BVT2733 from the scaffold promoted skin cell proliferation and migration while stimulating angiogenesis by upregulating HIF1-α/VEGF expression. The therapeutic effect of the scaffold was further confirmed in a full-thickness wound model using diabetic mice. The mice treated with the scaffolds exhibited an accelerated wound healing rate, increased neovascularization, enhanced collagen deposition, and regeneration of skin appendages within 2 weeks postinjury. The findings here provide evidence for the use of 11β-HSD1 inhibitor-integrated biomaterials in treating DUs and represent a novel biological platform for modulating dysregulated mechanisms in DUs.

Effects of HSD11B1 knockout and overexpression on local cortisol production and differentiation of mesenchymal stem cells

Exogenous glucocorticoids increase the risk for osteoporosis, but the role of endogenous glucocorticoids remains elusive. Here, we describe the generation and validation of a loss- and a gain-of-function model of the cortisol producing enzyme 11β-HSD1 (HSD11B1) to modulate the endogenous glucocorticoid conversion in SCP-1 cells — a model for human mesenchymal stem cells capable of adipogenic and osteogenic differentiation. CRISPR-Cas9 was successfully used to generate a cell line carrying a single base duplication and a 5 bp deletion in exon 5, leading to missense amino acid sequences after codon 146. These inactivating genomic alterations were validated by deep sequencing and by cloning with subsequent capillary sequencing. 11β-HSD1 protein levels were reduced by 70% in the knockout cells and cortisol production was not detectable. Targeted chromosomal integration was used to stably overexpress HSD11B1. Compared to wildtype cells, HSD11B1 overexpression resulted in a 7.9-fold increase in HSD11B1 mRNA expression, a 5-fold increase in 11β-HSD1 protein expression and 3.3-fold increase in extracellular cortisol levels under adipogenic differentiation. The generated cells were used to address the effects of 11β-HSD1 expression on adipogenic and osteogenic differentiation. Compared to the wildtype, HSD11B1 overexpression led to a 3.7-fold increase in mRNA expression of lipoprotein lipase (LPL) and 2.5-fold increase in lipid production under adipogenic differentiation. Under osteogenic differentiation, HSD11B1 knockout led to enhanced alkaline phosphatase (ALP) activity and mRNA expression, and HSD11B1 overexpression resulted in a 4.6-fold and 11.7-fold increase in mRNA expression of Dickkopf-related protein 1 (DKK1) and LPL, respectively. Here we describe a HSD11B1 loss- and gain-of-function model in SCP-1 cells at genetic, molecular and functional levels. We used these models to study the effects of endogenous cortisol production on mesenchymal stem cell differentiation and demonstrate an 11β-HSD1 dependent switch from osteogenic to adipogenic differentiation. These results might help to better understand the role of endogenous cortisol production in osteoporosis on a molecular and cellular level.

Equisetin is an anti-obesity candidate through targeting 11β-HSD1

Obesity is increasingly prevalent globally, searching for therapeutic agents acting on adipose tissue is of great importance. Equisetin (EQST), a meroterpenoid isolated from a marine sponge-derived fungus, has been reported to display antibacterial and antiviral activities. Here, we revealed that EQST displayed anti-obesity effects acting on adipose tissue through inhibiting adipogenesis in vitro and attenuating HFD-induced obesity in mice, doing so without affecting food intake, blood pressure or heart rate. We demonstrated that EQST inhibited the enzyme activity of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), a therapeutic target of obesity in adipose tissue. Anti-obesity properties of EQST were all offset by applying excessive 11β-HSD1's substrates and 11β-HSD1 inhibition through knockdown in vitro or 11β-HSD1 knockout in vivo. In the 11β-HSD1 bypass model constructed by adding excess 11β-HSD1 products, EQST's anti-obesity effects disappeared. Furthermore, EQST directly bond to 11β-HSD1 protein and presented remarkable better intensity on 11β-HSD1 inhibition and better efficacy on anti-obesity than known 11β-HSD1 inhibitor. Therefore, EQST can be developed into anti-obesity candidate compound, and this study may provide more clues for developing higher effective 11β-HSD1 inhibitors.

Metabolic Alteration Analysis of Steroid Hormones in Niemann-Pick Disease Type C Model Cell Using Liquid Chromatography/Tandem Mass Spectrometry

Niemann–Pick disease type C (NPC) is an autosomal recessive disease caused by a functional deficiency of cholesterol-transporting proteins in lysosomes, and exhibits various clinical symptoms. Since mitochondrial dysfunction in NPC has recently been reported, cholesterol catabolism to steroid hormones may consequently be impaired. In this study, we developed a comprehensive steroid hormone analysis method using liquid chromatography/tandem mass spectrometry (LC–MS/MS) and applied it to analyze changes in steroid hormone concentrations in NPC model cells. We investigated the analytical conditions for simultaneous LC–MS/MS analysis, which could be readily separated from each other and showed good reproducibility. The NPC phenotype was verified as an NPC model with mitochondrial abnormalities using filipin staining and organelle morphology observations. Steroid hormones in the cell suspension and cell culture medium were also analyzed. Steroid hormone analysis indicated that the levels of six steroid hormones were significantly decreased in the NPC model cell and culture medium compared to those in the wild-type cell and culture medium. These results indicate that some steroid hormones change during NPC pathophysiology and this change is accompanied by mitochondrial abnormalities.