Steroid receptor coactivator-3 differentially regulates the inflammatory response in peritoneal macrophages

Mechanism of bufalin inhibition of colon cancer liver metastasis by regulating M2-type polarization of Kupffer cells induced by highly metastatic colon cancer cells

Patients with metastatic colorectal cancer often have poor outcomes, primarily due to hepatic metastasis. Colorectal cancer (CRC) cells have the ability to secrete cytokines and other molecules that can remodel the tumor microenvironment, facilitating the spread of cancer to the liver. Kupffer cells (KCs), which are macrophages in the liver, can be polarized to M2 type, thereby promoting the expression of adhesion molecules that aid in tumor metastasis. Our research has shown that huachanshu (with bufalin as the main active monomer) can effectively inhibit CRC metastasis. However, the underlying mechanism still needs to be thoroughly investigated. We have observed that highly metastatic CRC cells have a greater ability to induce M2-type polarization of Kupffer cells, leading to enhanced metastasis. Interestingly, we have found that inhibiting the expression of IL-6, which is highly expressed in the serum, can reverse this phenomenon. Notably, bufalin has been shown to attenuate the M2-type polarization of Kupffer cells induced by highly metastatic Colorectal cancer (mCRC) cells and down-regulate IL-6 expression, ultimately inhibiting tumor metastasis. In this project, our aim is to study how high mCRC cells induce M2-type polarization and how bufalin, via the SRC-3/IL-6 pathway, can inhibit CRC metastasis. This research will provide a theoretical foundation for understanding the anti-CRC effect of bufalin.

Anti-inflammatory, analgesic and in vivo-in vitro wound healing potential of the Phlomis rigida Labill. extract

ETHNOPHARMACOLOGICAL RELEVANCE

The preparations of Phlomis aerial parts are used traditionally in Anatolia for wound healing and in inflammatory disorders.

METHODS

For the identification of the active fraction, the air dried aerial parts of Phlomis rigida Labill. were extracted by methanol and fractionated successively by n-hexane, dichloromethane and ethyl acetate, respectively. The phenolic constituents were characterized by the Folin-Ciocaltheu method; the antioxidant activity was performed by ABTS and DPPH radical scavenging assays. In vitro anti-inflammatory activity was evaluated by LOX enzyme inhibition, spectrophotometrically as well as cell cultures. The wound healing properties of P. rigida extract gels were studied via in vitro cell culture methods and in vivo by excisional wound model using Balb-c mice. The P. rigida extract was analyzed and characterized by GC-FID, GC-MS, and LC-MS.

RESULTS

The P. rigida methanol extract showed moderate LOX inhibitory at IC₅₀ = 19.5 ± 2.8 μg/mL whereas the antioxidant activity was by DPPH^• IC₅₀ = 0.89 mg/mL, and by ABTS^• IC₅₀ = 0.99 mg/mL, respectively. In addition, a remarkable P. rigida extracts anti-inflammatory activity was observed in the cell culture assay, which was then confirmed by the in vitro wound healing activity applied at 0.125-0.5 mg/mL concentrations, resulting in a dose-dependent increase in wound closure at the final stage. The P. rigida gel formulation was prepared to evaluate the extract in vivo, whereas the experimental results of the new gel formulation supported the findings of the in vitro wound healing activity.

CONCLUSION

The findings of this in vitro and in vivo study suggest that the wound healing and anti-inflammatory properties provide a scientific evidence of the ethnopharmacological application of Phlomis species.

Schizandrin A Protects Human Retinal Pigment Epithelial Cell Line ARPE-19 against HG-Induced Cell Injury by Regulation of miR-145

Diabetic retinopathy (DR) is a serious complication of diabetes, which is the main cause of blindness among adults. Traditional Chinese medicines (TCMs) have been proven to delay the development of DR. Nonetheless, the effect of Schizandrin A (SchA) on DR remains uninvestigated. The present study aimed to probe the protective effect of SchA on high-glucose (HG)-induced injury in ARPE-19 cells. We observed that SchA accelerated cell proliferation, prohibited apoptosis, and restrained pro-inflammatory cytokines (monocyte chemoattractant protein-1 [MCP-1], interleukin-6 [IL-6], and tumor necrosis factor alpha [TNF-α]) and reactive oxygen species (ROS) level in HG-stimulated cells. Additionally, miR-145 expression was upregulated in HG and SchA co-treated cells, and miR-145 inhibition reversed the protective effect of SchA on HG-managed ARPE-19 cells. Interestingly, downregulated myeloid differentiation factor 88 (MyD88) was found in HG and SchA co-treated cells, and upregulation of MyD88 was observed in miR-145 inhibitor-transfected cells. Additionally, SchA hindered nuclear factor κB (NF-κB) and p38 mitogen-activated protein kinase (p38MAPK) signaling pathways in HG-treated ARPE-19 cells. The findings validated that SchA could protect ARPE-19 cells from HG-induced cell injury by regulation of miR-145.

SRC-3/AIB-1 may Enhance Hepatic NFATC1 Transcription and Mediate Inflammation in a Tissue-Specific Manner in Morbid Obesity

BACKGROUND

Obesity is a global epidemic which is associated with several cardiometabolic comorbidities and is characterized by chronic, low grade systemic inflammation. Numerous biomarkers have been implicated in the pathophysiology of the disease, including transcription factors and coregulators. Steroid Receptor Coactivator (SRC)-family represent the master regulators of metabolic pathways and their dysregulation is strongly associated with numerous metabolic disorders.

METHODS

50 morbidly obese patients participated in the present study. Biopsies were collected from visceral adipose tissue, subcutaneous adipose tissue, skeletal muscle, extra-myocellular adipose tissue and liver. We evaluated the differential protein expression of NFATc1, SRC-2/TIF-2, SRC-3/AIB-1 and inflammatory biomarkers CD68 and CD3 by immunohistochemistry. The current study was designed to determine any correlations between the transcription factor NFATc1 and the SRC coregulators, as well as any associations with the inflammatory biomarkers.

RESULTS

We identified SRC-3 as a hepatic NFATc1 coactivator and we demonstrated its possible role in energy homeostasis and lipid metabolism. Moreover, we revealed a complex and extensive intraand inter-tissue network among the three main investigated proteins and the inflammatory biomarkers, suggesting their potential participation in the obesity-induced inflammatory cascade.

CONCLUSION

Steroid receptor coactivators are critical regulators of human metabolism with pleiotropic and tissue-specific actions. We believe that our study will contribute to the better understanding of the complex multi-tissue interactions that are disrupted in obesity and can therefore lead to numerous cardiometabolic diseases. Further on, our present findings suggest that SRC-3/AIB-1 could constitute possible future drug targets.

Dudleya brittonii extract promotes survival rate and M2-like metabolic change in porcine 3D4/31 alveolar macrophages

Objective

Although alveolar macrophages play a key role in the respiratory immunity of livestock, studies on the mechanism of differentiation and survival of alveolar macrophages are lacking. Therefore, we undertook to investigate changes in the lipid metabolism and survival rate, using 3D4/31 macrophages and Dudleya brittonii which has been used as a traditional asthma treatment.

Methods

3D4/31 macrophages were used as the in vitro porcine alveolar macrophages model. The cells were activated by exposure to phorbol 12-myristate 13-acetate (PMA). Dudleya brittonii extraction was performed with distilled water. For evaluating the cell survival rate, we performed the water-soluble tetrazolium salt cell viability assay and growth curve analysis. To confirm cell death, cell cycle and intracellular reactive oxygen species (ROS) levels were measured using flow cytometric analysis by applying fluorescence dye dichlorofluorescein diacetate and propidium iodide. Furthermore, we also evaluated cellular lipid accumulation with oil red O staining, and fatty acid synthesis related genes expression levels using quantitative polymerase chain reaction (qPCR) with SYBR green dye. Glycolysis, fatty acid oxidation, and tricarboxylic acid (TCA) cycle related gene expression levels were measured using qPCR after exposure to Dudleya brittonii extract (DB) for 12 h.

Results

The ROS production and cell death were induced by PMA treatment, and exposure to DB reduced the PMA induced downregulation of cell survival. The PMA and DB treatments upregulated the lipid accumulation, with corresponding increase in the acetyl-CoA carboxylase alpha, fatty acid synthase mRNA expressions. DB-PMA co-treatment reduced the glycolysis genes expression, but increased the expressions of fatty acid oxidation and TCA cycle genes.

Conclusion

This study provides new insights and directions for further research relating to the immunity of porcine respiratory system, by employing a model based on alveolar macrophages and natural materials.

Steroid Receptor Coactivator 3 Contributes to Host Defense against Enteric Bacteria by Recruiting Neutrophils via Upregulation of CXCL2 Expression

Steroid receptor coactivator 3 (SRC-3) is a transcriptional coactivator that interacts with nuclear receptors and some other transcription factors to enhance their effects on target gene transcription. We reported previously that SRC-3-deficient (SRC-3^-/-) mice are extremely susceptible to Escherichia coli-induced septic peritonitis as a result of uncontrolled inflammation and a defect in bacterial clearance. In this study, we observed significant upregulation of SRC-3 in colonic epithelial cells in response to Citrobacter rodentium infection. Based on these findings, we hypothesized that SRC-3 is involved in host defense against attaching and effacing bacterial infection. We compared the responses of SRC-3^-/- and wild-type mice to intestinal C. rodentium infection. We found that SRC-3^-/- mice exhibited delayed clearance of C. rodentium and more severe tissue pathology after oral infection with C. rodentium compared with wild-type mice. SRC-3^-/- mice expressed normal antimicrobial peptides in the colons but exhibited delayed recruitment of neutrophils into the colonic mucosa. Accordingly, SRC-3^-/- mice showed a delayed induction of CXCL2 and CXCL5 in colonic epithelial cells, which are responsible for neutrophil recruitment. At the molecular level, we found that SRC-3 can activate the NF-κB signaling pathway to promote CXCL2 expression at the transcriptional level. Collectively, we show that SRC-3 contributes to host defense against enteric bacteria, at least in part via upregulating CXCL2 expression to recruit neutrophils.

The levels of RAC3 expression are up regulated by TNF in the inflammatory response

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The inflammatory response increases the expression of RAC3 in vitro and in vivo.

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TNF induces the increase of RAC3 at transcriptional level through NF-κB activation.

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Glucocorticoids also induce the increase of RAC3 expression levels.

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RAC3 appears to be essential for NF-κB- and GR-mediated transcription.

RAC3 is a coactivator of glucocorticoid receptor and nuclear factor-κB (NF-κB) that is usually over-expressed in tumors and which also has important functions in the immune system. We investigated the role of the inflammatory response in the control of RAC3 expression levels in vivo and in vitro. We found that inflammation regulates RAC3 levels. In mice, sub-lethal doses of lipopolysaccharide induce the increase of RAC3 in spleen and the administration of the synthetic anti-inflammatory glucocorticoid dexamethasone has a similar effect. However, the simultaneous treatment with both stimuli is mutually antagonistic. In vitro stimulation of the HEK293 cell line with tumor necrosis factor (TNF), one of the cytokines induced by lipopolysaccharide, also increases the levels of RAC3 mRNA and protein, which correlates with an enhanced transcription dependent on the RAC3 gene promoter. We found that binding of the transcription factor NF-κB to the RAC3 gene promoter could be responsible for these effects. Our results suggest that increase of RAC3 during the inflammatory response could be a molecular mechanism involved in the control of sensitivity to both pro- and anti-inflammatory stimuli in order to maintain the normal healthy course of the immune response.

Anti-inflammatory and anti-nociceptive activities of methanol extract from aerial part of Phlomis younghusbandii Mukerjee

This study was designed to investigate the anti-inflammatory and anti-nociceptive activity of the methanol extract from the aerial part of Phlomis younghusbandii (MEAP) and to explore the possible related mechanisms. Anti-inflammatory effects of MEAP were evaluated by using the ear edema test induced by dimethylbenzene and vascular permeability test induced by acetic acid. Anti-nociceptive activities of MEAP were evaluated by the chemical nociception in models of acetic acid-induced writhing and formalin-induced hind paw licking, and by the thermal nociception in hot plate tests. Mechanisms of MEAP activities also were explored by evaluating expression levels of TNF-α, IL-6 and iNOS induced by LPS using real-time fluorogenic PCR and expression of COX-2 using Western blotting and an open-field test. The results indicated that the MEAP administered orally could significantly decrease ear edema induced by dimethylbenzene and increase vascular permeability induced by acetic acid. Additionally, the nociceptions induced by acetic acid and formalin were significantly inhibited. The anti-nociceptive effect could not be decreased by naloxone in the formalin test, and MEAP did not affect the normal autonomic activities of mice. Expression levels of pro-inflammatory cytokines (TNF-α, IL-6, iNOS) induced by LPS were decreased obviously by treatment with MEAP. Furthermore, COX-2 expression in the spinal dorsal horns of the pain model mice induced by formalin was significantly down-regulated by MEAP. In conclusion, MEAP has significant anti-inflammatory and antinociceptive activities, and the mechanisms may be related to the down-regulated expression of TNF-α, IL-6, iNOS and COX-2.

Effects of neurolytic celiac plexus block on liver regeneration in rats with partial hepatectomy

Liver regeneration is the basic physiological process after partial hepatectomy (PH), and is important for the functional rehabilitation of the liver after acute hepatic injury. This study was designed to explore the effects of neurolytic celiac plexus block (NCPB) on liver regeneration after PH. We established a model of PH in rats, assessing hepatic blood flow, liver function, and serum CRP, TNF-α, IL-1β and IL-6 concentrations of the residuary liver after PH. Additionally, histopathological studies, immunohistochemistry, and western blotting were also performed. Our results indicated that NCPB treatment after PH improved liver regeneration and survival rates, increased hepatic blood flow, reduced hepatocyte damage, decreased the secretion and release of inflammatory cytokines, increased the expression of B cell lymphoma/leukemia-2 (Bcl-2), and decreased the expression of Bcl-2 associated X protein (Bax). Additionally, Western blotting revealed that the expression of NF-κB p65 and c-Jun were decreased in liver after NCPB. In conclusion, the results of our present study indicate that NCPB treatment has a favorable effect on liver regeneration after PH. We suggest that NCPB can be utilized as an effective therapeutic method to help the functional rehabilitation of the liver after acute hepatic injury or liver cancer surgery.