Estrogen receptor β alleviates inflammatory lesions in a rat model of inflammatory bowel disease via down-regulating P2X7R expression in macrophages

A comprehensive review of small molecules, targets, and pathways in ulcerative colitis treatment

Ulcerative colitis (UC), a chronic inflammatory bowel disease (IBD), poses significant clinical challenges because of its complex pathophysiology, long-term nature, and the limited efficacy of existing treatments. Small-molecule compounds, particularly those that are able to modulate inflammation-related signaling pathways and, in many cases, occur in nature, offer a promising alternative or supplement to conventional therapies. Studies on molecules for UC therapeutics reported in 1394 publications over the past 30 years were collected from the Web of Science (WOS) database. Only studies that verified therapeutic efficacy through animal experiments were included. Through an analysis of the molecular classes, structures, common targets, and pathways using network pharmacology, we identified 14 classes of compounds, 5 direct-target modules, and 3 crucial downstream pathways. Alkaloids, phenylpropanoids, flavonoids, and terpenes (and their derivatives) appeared most frequently and mainly targeted lipid metabolism, oxidative stress, immune regulation, signaling transduction, and cancer-related pathways. Notably, there has been an increasing trend of applying naturally sourced compounds in both preclinical and clinical trials, especially flavonoids, over the last five years. Although progress in UC research has been made, the majority of studies have focused on the overall therapeutic effects and biomarker alterations, with limited emphasis on the direct targets and underlying mechanisms. These findings highlight the need to explore novel small-molecule therapeutic strategies for UC, focusing on clearly defined targets and precise modes of action.

Estrogen receptor β activation alleviates inflammatory bowel disease by suppressing NLRP3-dependent IL-1β production in macrophages via downregulation of intracellular calcium level

INTRODUCTION

Although several estrogen receptor β (ERβ) agonists have been reported to alleviate IBD, the pivotal mechanism remains obscure.

OBJECTIVES

To examine the effects and mechanisms of ERβ activation on cytokine/chemokine networks in colitis mice.

METHODS

Dextran sulfate sodium salt (DSS) and trinitro-benzene-sulfonic acid (TNBS) were used to induce mouse colitis model. Multiple molecular biological methods were employed to evaluate the severity of mouse colitis and the level of cytokine and/or chemokine.

RESULTS

Bioinformatics analysis, ELISA and immunofluorescence results showed that the targeted cytokines and/or chemokines associated with ERβ expression and activation is IL-1β, and the anti-colitis effect of ERβ activation was significantly attenuated by the overexpression of AAV9-IL-1β. Immunofluorescence analysis indicated that ERβ activation led to most evident downregulation of IL-1β expression in colonic macrophages as compared to monocytes and neutrophils. Given the pivotal roles of NLRP3, NLRC4, and AIM2 inflammasome activation in the production of IL-1β, we examined the influence of ERβ activation on inflammasome activity. ELISA and WB results showed that ERβ activation selectively blocked the NLRP3 inflammasome assembly-mediated IL-1β secretion. The calcium-sensing receptor (CaSR) and calcium signaling play crucial roles in the assembly of the NLRP3 inflammasome. WB and immunofluorescence results showed that ERβ activation reduced intracellular CaSR expression and calcium signaling in colonic macrophages. Combination with CaSR overexpression plasmid reversed the suppressive effect of ERβ activation on NLRP3 inflammasome assembly, and counteracting the downregulation of IL-1β secretion.

CONCLUSION

Our research uncovers that the anti-colitis effect of ERβ activation is accomplished through the reduction of IL-1β levels in colonic tissue, achieved by specifically decreasing CaSR expression in macrophages to lower intracellular calcium levels and inhibit NLRP3 inflammasome assembly-mediated IL-1β production.

Estrogen receptor β alleviates colitis in intestinal epithelial cells and activates HIF-1a and ATG-9a-mediated autophagy

Estrogen receptor β (ERβ) plays a pivotal role in regulating intestinal epithelial function and inflammation. Its involvement in inflammatory bowel diseases (IBD), particularly in ulcerative colitis (UC), remains poorly understood, despite emerging evidence pointing to its anti-inflammatory properties. This study investigated ERβ expression in UC patients using quantitative PCR, Western blot, and immunofluorescence. To investigate the functional role of ERβ, a DSS-induced colitis mouse model and LPS-treated HT-29 cells were used. Autophagy activity was evaluated through Western blot, transmission electron microscopy (TEM), and autophagy inhibitors. Co-immunoprecipitation (Co-IP) and dual luciferase reporter assays were employed to explore the interaction between ERβ and hypoxia-inducible factor-1α (HIF-1α), as well as the regulation of ATG-9a expression. The results demonstrated that ERβ expression was significantly downregulated in the inflammatory colons of UC patients. In vivo, ERβ activation by ERB041 alleviated DSS-induced colitis in mice, reducing weight loss, histopathological damage, and inflammatory cytokine levels. In vitro, ERB041 enhanced autophagy in LPS-treated HT-29 cells, accompanied by a reduction in pro-inflammatory cytokines. Furthermore, ERβ activation promoted the expression of tight junction proteins and preserved epithelial barrier integrity. Co-IP and dual luciferase assays revealed that ERβ interacted with HIF-1α and modulated ATG-9a-mediated autophagy. These results indicate that ERβ alleviates intestinal inflammation and activates HIF-1a and ATG-9a-mediated autophagy, providing new insights into the therapeutic potential of targeting ERβ in UC and highlighting its role in maintaining intestinal homeostasis.

Estrogen Receptor β Alleviates Colitis by Inhibiting Ferroptosis in Intestinal Epithelial Cells

Background

Ulcerative colitis (UC), a major type of inflammatory bowel disease, is characterized by chronic inflammation of the colonic mucosa and submucosa. Estrogen receptor β (ERβ) predominates in the colon and exerts anti-inflammatory effects. Ferroptosis, a recently discovered form of iron-dependent programmed cell death, is implicated in the pathogenesis of several diseases, including UC. However, the link between ferroptosis and the anti-inflammatory actions of ERβ in UC remains to be elucidated.

Methods

We analyzed colonic mucosal samples from inflammatory and non-inflammatory regions of UC patients to assess ferroptosis levels. Experimental colitis was induced in wild-type C57BL/6 mice and intestinal epithelial cell-specific ERβ knockout (ERβ-/-) mice using dextran sulfate sodium (DSS). We measured body weight, colon length, disease activity index (DAI), and histopathological scores. RNA sequencing was performed to identify differentially expressed genes and related signaling pathways, with additional ferroptosis assessment in vivo and in vitro through biochemical markers and cellular assays.

Results

In UC patients, ferroptosis was significantly elevated in inflammatory mucosal regions compared to non-inflammatory areas. Compared to the wild-type counterparts, ERβ-/- mice exacerbated DSS-induced experimental colitis, including reduced body weight, shortened colon length, and higher DAI scores. RNA sequencing showed enrichment of inflammatory and immune response pathways, with significant activation of JAK/STAT, NF-κB, and TNF signaling in ERβ-/- mice. ERβ deficiency induced ferroptosis in both in vitro and in vivo models. Ferroptosis indicators such as PTGS2 were upregulated, GPX4 expression was downregulated, and there were increases in malondialdehyde, iron content, reactive oxygen species, and mitochondrial damage.

Conclusion

Our findings demonstrate that ERβ deficiency exacerbates colitis and enhances ferroptosis in IECs. ERβ positively regulates GPX4 transcription, thereby inhibiting ferroptosis and alleviating colitis. These insights suggest that modulation of ERβ and its regulation of ferroptosis may represent a novel therapeutic strategy for UC.

G Protein-Coupled Estrogen Receptor-Mediated Anti-Inflammatory and Mucosal Healing Activity of a Trimethylpyridinol Analogue in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is characterized by abnormal immune responses, including elevated proinflammatory cytokines, such as tumor necrosis factor-α (TNFα) and interleukin-6 (IL-6) in the gastrointestinal (GI) tract. This study presents the synthesis and anti-inflammatory evaluation of 2,4,5-trimethylpyridin-3-ol analogues, which exhibit dual inhibition of TNFα- and IL-6-induced inflammation. Analysis using in silico methods, including 3D shape-based target identification, modeling, and docking, identified G protein-coupled estrogen receptor 1 (GPER) as the molecular target for the most effective analogue, 6-26, which exhibits remarkable efficacy in ameliorating inflammation and restoring colonic mucosal integrity. This was further validated by surface plasmon resonance (SPR) assay results, which showed direct binding to GPER, and by the results showing that GPER knockdown abolished the inhibitory effects of 6-26 on TNFα and IL-6 actions. Notably, 6-26 displayed no cytotoxicity, unlike G1 and G15, a well-known GPER agonist and an antagonist, respectively, which induced necroptosis independently of GPER. These findings suggest that the GPER-selective compound 6-26 holds promise as a therapeutic candidate for IBD.

Synergistic Anti-Cancer Effects of ERB-041 and Genistein through Estrogen Receptor Suppression-Mediated PI3K/AKT Pathway Downregulation in Canine Mammary Gland Tumor Cells

Canine-mammary-gland tumors (CMTs) are prevalent in female dogs, with approximately 50% of them being malignant and often presenting as inoperable owing to their size or metastasis. Owing to poor outcomes, effective alternatives to conventional chemotherapy for humans are necessary. Two estrogen receptors, estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ), which act in opposition to each other, are involved, and CMT growth involves ERα through the phosphoinositide 3-kinases (PI3K)/AKT pathway. In this study, we aimed to identify the synergistic anti-cancer effects of ERB-041, an ERβ agonist, and genistein, an isoflavonoid from soybeans known to have ERβ-specific pseudo-estrogenic actions, on CMT-U27 and CF41.Mg CMT cell lines. ERB-041 and genistein synergistically inhibited cell proliferation and increased the number of annexin V-positive cells in both cell lines. Furthermore, we observed a synergistic increase in the Bax/Bcl-2 ratio and cleaved caspase-3 expression. Additionally, cell-cycle arrest occurred through the synergistic regulation of cyclin D1 and cyclin-dependent kinase 4 (CDK4). We also found a synergistic decrease in the expression of ERα, and the expression of proteins involved in the PI3K/AKT pathway, including p-PI3K, phosphatase and tensin homolog (PTEN), AKT, and mechanistic target of rapamycin (mTOR). In conclusion, ERB-041 and genistein exhibited a synergistic anticancer effect on CMTs, suggesting that cotreatment with ERB-041 and genistein is a promising treatment for CMTs.

Ameliorative effects of androstenediol against acetic acid-induced colitis in male wistar rats via inhibiting TLR4-mediated PI3K/Akt and NF-κB pathways through estrogen receptor β activation

5-androstenediol (ADIOL) functions as a selective estrogen receptor β (ERβ) ligand with a protective effect against many diseases. So, we conducted a novel insight into its role in acetic acid (AA)-induced colitis and investigated its effect on TLR4-Mediated PI3K/Akt and NF-κB Pathways and the potential role of ERβ as contributing mechanisms.

METHODS

Rats were randomized into 5 Groups; Control, Colitis, Colitis + mesalazine (MLZ), Colitis + ADIOL, and Colitis + ADIOL + PHTPP (ER-β antagonist). The colitis was induced through a rectal enema of acetic acid (AA) on the 8th day. At the end of treatment, colons were collected for macroscopic assessment. Tissue levels of malondialdehyde (MDA), superoxide dismutase (SOD), nuclear factor kappa b (NF-κB), toll-like receptor (TLR4), and phosphorylated Protein kinase B (pAKT) were measured. Besides, Gene expression of interleukin-1beta (IL-1β), metalloproteases 9 (Mmp9), inositol 3 phosphate kinase (PI3K), Neutrophil gelatinase-associated lipocalin (NGAL), ERβ and NLRP6 were assessed. Histopathological and immunohistochemical studies were also investigated.

RESULTS

Compared to the untreated AA group, the disease activity index (DAI) and macroscopic assessment indicators significantly decreased with ADIOL injections. Indeed, ADIOL significantly decreased colonic tissue levels of MDA, TLR4, pAKT, and NF-κB immunostainig while increased SOD activity and β catenin immunostainig. ADIOL mitigated the high genetic expressions of IL1β, NGAL, MMP9, and PI3K while increased ERβ and NLRP6 gene expression. Also, the pathological changes detected in AA groups were markedly ameliorated with ADIOL. The specific ERβ antagonist, PHTPP, largely diminished these protective effects of ADIOL.

CONCLUSION

ADIOL could be beneficial against AA-induced colitis mostly through activating ERβ.

Administration of an AAV vector coding for a P2X7-blocking nanobody-based biologic ameliorates colitis in mice

BACKGROUND

The pro-inflammatory ATP-gated P2X7 receptor is widely expressed by immune and non-immune cells. Nanobodies targeting P2X7, with potentiating or antagonistic effects, have been developed. Adeno-associated virus (AAV)-mediated gene transfer represents an efficient approach to achieve long-term in vivo expression of selected nanobody-based biologics. This approach (AAVnano) was used to validate the relevance of P2X7 as a target in dextran sodium sulfate (DSS)-induced colitis in mice.

RESULTS

Mice received an intramuscular injection of AAV vectors coding for potentiating (14D5-dimHLE) or antagonistic (13A7-Fc) nanobody-based biologics targeting P2X7. Long-term modulation of P2X7 activity was evaluated ex vivo from blood samples. Colitis was induced with DSS in mice injected with AAV vectors coding for nanobody-based biologics. Severity of colitis, colon histopathology and expression of chemokines and cytokines were determined to evaluate the impact of P2X7 modulation. A single injection of an AAV vector coding for 13A7-Fc or 14D5-dimHLE efficiently modulated P2X7 function in vivo from day 15 up to day 120 post-injection in a dose-dependent manner. An AAV vector coding for 13A7-Fc significantly ameliorated DSS-induced colitis and significantly reduced immune cell infiltration and expression of chemokines and proinflammatory cytokines in colonic tissue.

CONCLUSIONS

We have demonstrated the validity of AAVnano methodology to modulate P2X7 functions in vivo. Applying this methodological approach to a DSS-induced colitis model, we have shown that P2X7 blockade reduces inflammation and disease severity. Hence, this study confirms the importance of P2X7 as a pharmacological target and suggests the use of nanobody-based biologics as potential therapeutics in inflammatory bowel disease.

Estrogen plays an important role by influencing the NLRP3 inflammasome

The nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome is an important part of the natural immune system that plays an important role in many diseases. Estrogen is a sex hormone that plays an important role in controlling reproduction and regulates many physiological and pathological processes. Recent studies have indicated that estrogen is associated with disease progression. Estrogen can ameliorate some diseases (e. g, sepsis, mood disturbances, cerebral ischemia, some hepatopathy, Parkinson's disease, amyotrophic lateral sclerosis, inflammatory bowel disease, spinal cord injury, multiple sclerosis, myocardial ischemia/reperfusion injury, osteoarthritis, and renal fibrosis) by inhibiting the NLRP3 inflammasome. Estrogen can also promote the development of diseases (e.g., ovarian endometriosis, dry eye disease, and systemic lupus erythematosus) by upregulating the NLRP3 inflammasome. In addition, estrogen has a dual effect on the development of cancers and asthma. However, the mechanism of these effects is not summarized. This article reviewed the progress in understanding the effects of estrogen on the NLRP3 inflammasome and its mechanisms in recent years to provide a theoretical basis for an in-depth study.

Naringenin as a natural immunomodulator against T cell-mediated autoimmune diseases: literature review and network-based pharmacology study

T cells, especially CD4+ T helper (Th) cells, play a vital role in the pathogenesis of specific autoimmune diseases. Naringenin, a citrus flavonoid, exhibits anti-inflammatory, anti-oxidant, and antitumor properties, which have been verified in animal autoimmune disease models. However, naringenin's possible effects and molecular mechanisms in T cell-mediated autoimmune diseases are unclear. This review summarizes the findings of previous studies and predicts the target of naringenin in T cell-mediated autoimmune disorders such as multiple sclerosis, inflammatory bowel disease, and rheumatoid arthritis through network pharmacology analysis. We performed DAVID enrichment analysis, protein-protein interaction analysis, and molecular docking to predict the positive effect of naringenin on T cell-mediated autoimmune disorders. Sixteen common genes were screened, among which the core genes were PTGS2, ESR1, CAT, CASP3, MAPK1, and AKT1. The possible molecular mechanism relates to HIF-1, estrogen, TNF, and NF-κB signaling pathways. Our findings have significance for future naringenin treatment of T cell-mediated autoimmune diseases.

17β-estradiol modulates the expression of hormonal receptors on THP-1 T. gondii-infected macrophages and monocytes in an AKT and ERK-dependent manner

Toxoplasma gondii (T. gondii) is a parasite common in pregnancy. Monocytes and macrophages are a significant immunologic barrier against T. gondii by boosting up inflammation. This outcome is highly regulated by signaling pathways such as MAPK (ERK1/2) and PI3K (AKT), necessary in cell growth and proliferation. It may be associated with the hormonal receptors' modulation by T. gondii (Estrogen Receptor (ER)-α, ERβ, G Protein-coupled ER (GPER), and Prolactin Receptor (PRLR)), as previously reported by our research group. 17β-estradiol also activates MAPK and PI3K; however, its combined effect in THP-1 monocytes and macrophages, infected with T. gondii, has not yet been evaluated. This study aimed to evaluate the combined effect of 17β-estradiol in the activation of signaling pathways using a model of THP-1 monocytes and macrophages infected with T. gondii. THP-1 monocytes were cultured and differentiated into macrophages. Inhibition of AKT and ERK1/2 was performed with specific inhibitors. Stimuli were performed with 17β-estradiol (10 nM), T. gondii (20,000 tachyzoites), and both conditions for 48 h. Proteins were extracted and quantified, and Western Blot assays were performed. 17β-estradiol performed activation of ERK1/2 and AKT in T. gondii-infected macrophages. 17β-estradiol modulated the expression of hormonal receptors in infected cells: increases the PRLR and PrgR in T. gondii-infected macrophages and decreases the PRLR and ERα in T. gondii-infected monocytes. As for GPER, its expression is abolished by T. gondii, and 17β-estradiol cannot restore it. Finally, the blockage of ERK and AKT pathways modified the expression of hormonal receptors. In conclusion, 17β-estradiol modifies the receptors of T. gondii-infected THP1 macrophages and monocytes in an ERK/AKT dependent manner.

The role of P2X7 receptor in infection and metabolism: Based on inflammation and immunity

The P2X7 receptor (P2X7R) is a ligand-gated receptor belonging to the P2 receptor family. It is distributed in various tissues of the human body and is involved in regulating the physiological functions of tissues and cells to affect the occurrence and development of diseases. Unlike all other P2 receptors, the P2X7 receptor is mainly expressed in immune cells and can be activated not only by extracellular nucleotides but also by non-nucleotide substances which act as positive allosteric modulators. In this review, we comprehensively describe the role of the P2X7 receptor in infection and metabolism based on its role as an important regulator of inflammation and immunity, and briefly introduce the structure and general function of the P2X7 receptor. These provide a clear knowledge framework for the study of the P2X7 receptor in human health. Targeting the P2X7 receptor may be an effective method for the treatment of inflammatory and immune diseases. And its role in microbial infection and metabolism may be the main direction for in-depth research on the P2X7 receptor in the future.

Bazedoxifene, a Selective Estrogen Receptor Modulator, Promotes Functional Recovery in a Spinal Cord Injury Rat Model

In research on various central nervous system injuries, bazedoxifene acetate (BZA) has shown two main effects: neuroprotection by suppressing the inflammatory response and remyelination by enhancing oligodendrocyte precursor cell differentiation and oligodendrocyte proliferation. We examined the effects of BZA in a rat spinal cord injury (SCI) model. Anti-inflammatory and anti-apoptotic effects were investigated in RAW 264.7 cells, and blood-spinal cord barrier (BSCB) permeability and angiogenesis were evaluated in a human brain endothelial cell line (hCMEC/D3). In vivo experiments were carried out on female Sprague Dawley rats subjected to moderate static compression SCI. The rats were intraperitoneally injected with either vehicle or BZA (1mg/kg pre-SCI and 3 mg/kg for 7 days post-SCI) daily. BZA decreased the lipopolysaccharide-induced production of proinflammatory cytokines and nitric oxide in RAW 264.7 cells and preserved BSCB disruption in hCMEC/D3 cells. In the rats, BZA reduced caspase-3 activity at 1 day post-injury (dpi) and suppressed phosphorylation of MAPK (p38 and ERK) at dpi 2, hence reducing the expression of IL-6, a proinflammatory cytokine. BZA also led to remyelination at dpi 20. BZA contributed to improvements in locomotor recovery after compressive SCI. This evidence suggests that BZA may have therapeutic potential to promote neuroprotection, remyelination, and functional outcomes following SCI.