Berberine attenuates epithelial mesenchymal transition in bleomycin-induced pulmonary fibrosis in mice via activating A2aR and mitigating the SDF-1/CXCR4 signaling

AIMS

Berberine is endowed with anti-oxidant, anti-inflammatory and anti-fibrotic effects. This study explored the role of adenosine A_2a receptor (A_2aR) activation and SDF-1/CXCR4 signaling suppression in the protective effects of berberine in bleomycin-induced pulmonary fibrosis in mice.

MAIN METHODS

Pulmonary fibrosis was generated in mice by injecting bleomycin (40 U/kg, i.p.) on days 0, 3, 7, 10 and 14. Mice were treated with berberine (5 mg/kg, i.p.) from day 15 to day 28.

KEY FINDINGS

Severe lung fibrosis and increased collagen content were observed in the bleomycin-challenged mice. Pulmonary A_2aR downregulation was documented in bleomycin-induced pulmonary fibrosis animals and was accompanied by enhanced expression of SDF-1/CXCR4. Moreover, TGF-β1elevation and pSmad2/3 overexpression were reported in parallel with enhanced epithelial mesenchymal transition (EMT) markers expression, vimentin and α-SMA. Besides, bleomycin significantly elevated the inflammatory and pro-fibrogenic mediator NF-κB p65, TNF-α and IL-6. Furthermore, bleomycin administration induced oxidative stress as depicted by decreased Nrf2, SOD, GSH and catalase levels. Interestingly, berberine administration markedly ameliorated the fibrotic changes in lungs by modulating the purinergic system through the inhibition of A_2aR downregulation, mitigating EMT and effectively suppressing inflammation and oxidative stress. Strikingly, A_2aR blockade by SCH 58261, impeded the pulmonary protective effect of berberine.

SIGNIFICANCE

These findings indicated that berberine could attenuate the pathological processes of bleomycin-induced pulmonary fibrosis at least partially via upregulating A_2aR and mitigating the SDF-1/CXCR4 related pathway, suggesting A_2aR as a potential therapeutic target for the management of pulmonary fibrosis.

Estradiol-17β upregulates pyruvate kinase M2 expression to coactivate estrogen receptor-α and to integrate metabolic reprogramming with the mitogenic response in endometrial cells

CONTEXT

Proliferating cells reprogram their cellular glucose metabolism to meet the bioenergetic and biosynthetic demands and to maintain cellular redox homeostasis. Pyruvate kinase M (PKM) is a critical regulator of this metabolic reprogramming. However, whether estradiol-17β (E2) reprograms cellular metabolism to support proliferation of human primary endometrial stromal cells (hESCs) and the molecular basis of this reprogramming are not well understood.

OBJECTIVES

Our objectives were to study whether E2 induces reprogramming of glucose metabolism in hESCs and to investigate the potential roles of PKM2 in E2-induced metabolic reprogramming and proliferation of these cells.

METHODS

The oxygen consumption rate and extracellular acidification rate were assessed by a Seahorse XF24 analyzer. PKM2 expression was assessed by real-time RT-PCR and immunoblotting.

RESULTS

E2 induces a Warburg-like glucose metabolism in hESCs by inducing the expression of PKM. E2 also enhanced PKM splicing into the PKM2 isoform by upregulating the c-Myc-hnRNP axis. Furthermore, E2 induces PKM2 oxidation, phosphorylation, and nuclear translocation. In addition to its glycolytic function, PKM2 physically interacted with estrogen receptor-α (ERα) and functioned as an ERα coactivator. Small-molecule PKM2 activators ameliorated ERα transcriptional activity and abrogated the E2-induced hESC proliferation.

CONCLUSIONS

We show for the first time that E2-induced hESC proliferation is associated with a shift in glucose metabolism toward aerobic glycolysis, and the molecular basis for this metabolic shift is linked to the effects of E2 on PKM2. In addition, PKM2 acts as a transcriptional coactivator for ERα and small-molecule PKM2 activators inhibit ERα transcriptional activity and reduce E2-induced cell proliferation.

2-Methoxyestradiol causes functional repression of transforming growth factor β3 signaling by ameliorating Smad and non-Smad signaling pathways in immortalized uterine fibroid cells

OBJECTIVE

To investigate the effects and the mechanism of action of 2-methoxyestradiol (2ME(2)) on transforming growth factor (TGF) β3-induced profibrotic response in immortalized human uterine fibroid smooth muscle (huLM) cells.

DESIGN

Laboratory study.

SETTING

University research laboratory.

PATIENTS(S)

Not applicable.

INTERVENTIONS(S)

Not applicable.

MAIN OUTCOME MEASURE(S)

huLM cells were treated with TGF-β3 (5 ηg/mL) in the presence or absence of specific Smad3 inhibitor SIS3 (1 μmol/L), inhibitor of the PI3K/Akt (LY294002, 10 μmol/L), or 2ME(2) (0.5 μmol/L), and the expression of collagen (Col) type I(αI), Col III(αI), plasminogen activator inhibitor (PAI) 1, connective tissue growth factor (CTGF), and α-smooth muscle actin (α-SMA) were determined by real-time reverse-transcription polymerase chain reaction and immunoblotting. The effect of 2ME(2) on Smad-microtubule binding was evaluated by coimmunoprecipitation.

RESULT(S)

Our data revealed that TGF-β3-induced fibrogenic response in huLM is mediated by both Smad-dependent and Smad-independent PI3K/Akt/mTOR signaling pathways. 2ME(2) abrogates TGF-β3-induced expression of Col I(αI), Col III(αI), PAI-1, CTGF, and α-SMA. Molecularly, 2ME(2) ameliorates TGF-β3-induced Smad2/3 phosphorylation and nuclear translocation. In addition, 2ME(2) inhibits TGF-β3-induced activation of the PI3K/Akt/mTOR pathway.

CONCLUSION(S)

TGF-β3-induced profibrotic response in fibroid cells is mediated by Smad-dependent and Smad-independent PI3K/Akt/mTOR pathways. 2ME(2) inhibits TGF-β3 profibrotic effects in huLM cells by ameliorating both Smad-dependent and Smad-independent signaling pathways.

Catechol-o-methyltransferase expression and 2-methoxyestradiol affect microtubule dynamics and modify steroid receptor signaling in leiomyoma cells

Context

Development of optimal medicinal treatments of uterine leiomyomas represents a significant challenge. 2-Methoxyestradiol (2ME) is an endogenous estrogen metabolite formed by sequential action of CYP450s and catechol-O-methyltransferase (COMT). Our previous study demonstrated that 2ME is a potent antiproliferative, proapoptotic, antiangiogenic, and collagen synthesis inhibitor in human leiomyomas cells (huLM).

Objectives

Our objectives were to investigate whether COMT expression, by the virtue of 2ME formation, affects the growth of huLM, and to explore the cellular and molecular mechanisms whereby COMT expression or treatment with 2ME affect these cells.

Results

Our data demonstrated that E₂-induced proliferation was less pronounced in cells over-expressing COMT or treated with 2ME (500 nM). This effect on cell proliferation was associated with microtubules stabilization and diminution of estrogen receptor α (ERα) and progesterone receptor (PR) transcriptional activities, due to shifts in their subcellular localization and sequestration in the cytoplasm. In addition, COMT over expression or treatment with 2ME reduced the expression of hypoxia-inducible factor -1α (HIF-1 α) and the basal level as well as TNF-α-induced aromatase (CYP19) expression.

Conclusions

COMT over expression or treatment with 2ME stabilize microtubules, ameliorates E₂-induced proliferation, inhibits ERα and PR signaling, and reduces HIF-1 α and CYP19 expression in human uterine leiomyoma cells. Thus, microtubules are a candidate target for treatment of uterine leiomyomas. In addition, the naturally occurring microtubule-targeting agent 2ME represents a potential new therapeutic for uterine leiomyomas.

Effect of tumor necrosis factor-alpha on estrogen metabolism and endometrial cells: potential physiological and pathological relevance

CONTEXT

Estrogen and its metabolites play a critical role in the pathophysiology of the endometrium. The bioavailability of estrogen and estrogen metabolites in endometrial tissues depends on the expression of enzymes involved in estrogen biosynthesis and metabolism. Substantial evidence indicates that estrogen-dependent endometrial disorders are also associated with proinflammatory milieu. However, the mechanism whereby inflammation contributes to these conditions is not known.

OBJECTIVE

The objective of the study was to investigate the effect of TNF-alpha on estrogen metabolism and the expression of estrogen-metabolizing genes in human endometrial glandular epithelial cells (EM1).

DESIGN

EM1 were treated with 17beta-estradiol (E2) with or without TNF-alpha. Capillary liquid chromatography-tandem mass spectrometry analysis was used for quantitative measurement of estrogens and estrogen metabolites. Western blot analysis, reporter gene assay, and real-time RT-PCR were used to assess the expression of estrogen-metabolizing genes.

RESULTS

TNF-alpha treatment significantly increased the level of total estrogen and estrogen metabolites and significantly increased the rate of conversion of estrone (E1) into E2. TNF-alpha also enhanced the oxidative metabolism of estrogen into catecholestrogens with concomitant inhibition of their conversion into methoxyestrogens. Gene expression analysis revealed that TNF-alpha induced the expression of genes involved in E2 biosynthesis (steroidogenic factor-1 and aromatase) and activation (17beta- hydroxysteroid dehydrogenase type 1 and cytochrome P-450, 1B1) with simultaneous repression of genes involved in estrogen inactivation (17beta-hydroxysteroid dehydrogenase type 2; catechol O-methyltransferase; and nicotinamide adenine dinucleotide phosphate-quinone oxidoreductase 1).

CONCLUSION

TNF-alpha increases the local estrogen biosynthesis in human endometrial glandular cells and directs estrogen metabolism into more hormonally active and carcinogenic metabolites. These effects may impact many physiological and pathological processes that occur within the endometrium.