Anti- Versus Pro-Inflammatory Metabololipidome Upon Cupping Treatment.

BACKGROUND/AIMS: This study aimed to explore the metabololipidome in mice upon cupping treatment. METHODS: A nude mouse model mimicking the cupping treatment in humans was established by administrating four cupping sets on the back skin for 15 minutes. UPLC-MS/ MS was performed to determine the PUFA metabolome in mice skin and blood before and after cupping treatment. The significantly changed lipids were administered in macrophages to assess the production of pro-inflammatory cytokines IL-6 and TNF-α by ELISA. RESULTS: The anti-inflammatory lipids, e.g. PGE1, 5,6-EET, 14,15-EET, 10S,17S-DiHDoHE, 17R-RvD1, RvD5 and 14S-HDoHE were significantly increased while pro-inflammatory lipids, e.g. 12-HETE and TXB2 were deceased in the skin or plasma post cupping treatment. Cupping treatment reversed the LPS-stimulated IL-6 and TNF-α expression in mouse peritoneal exudates. Moreover, 5,6-EET, PGE1 decreased the level of TNF-α, while 5,6-EET, 5,6-DHET downregulated IL-6 production in macrophages. Importantly, 14,15-EET and 14S-HDoHE inhibited both IL-6 and TNF-α induced by lipopolysaccharide (LPS). 17-RvD1, RvD5 and PGE1 significantly reduced the LPS-initiated TNF-α, while TXB2 and 12-HETE further upregulated the LPS-enhanced IL-6 and TNF-α expression in macrophages. CONCLUSION: Our results reveal the identities of anti-inflammatory versus pro-inflammatory metabolipidome and suggest the potential therapeutic mechanism of cupping treatment.

Glucocorticoid exposure in early placentation induces preeclampsia in rats via interfering trophoblast development.

In pregnancy, placenta can be exposed to glucocorticoids (GCs) via several ways, which may disturb placentation and adversely affect pregnancy. Preeclampsia (PE) is thought to be attributed, in part, to impaired trophoblast development. The purpose of the present study was to confirm that GC exposure in early placentation could lead to PE in rats, with the mechanisms involving dysregulated trophoblast development. In the study, pregnant rats were administered with 2.5mg/kg Dex subcutaneously once per day from gestational day 7 to 13. Maternal systolic blood pressure and urinary albumin were increased, while both fetus and placenta were restricted after GC exposure relative to the control group. GC exposure also contributed to placental abnormalities and renal impairment. Moreover, placental oxidative damage was increased along with placental hypoxia-inducible factor 1-alpha (HIF1A) overexpression after GC treatment. Mechanically, GC induced PE in rat partially through inhibiting trophoblast proliferation, migration, invasion and epithelial-mesenchymal transition (EMT), which involved phospho-extracellular signal regulated kinase (p-ERK) downregulation. Furthermore, GC receptor was required for the inhibition of GC on trophoblast proliferation, migration, invasion and EMT in vitro. These findings suggest that GC exposure in early placentation could contribute to PE in pregnant rats, with the mechanisms involving inhibition of trophoblast proliferation, migration, invasion and EMT by GC.

Spontaneous miscarriages are explained by the stress/glucocorticoid/lipoxin A4 axis.

Despite various suspected causes, ranging from endocrine and genetic to infectious and immunological aspects, the molecular mechanisms of miscarriage still remain enigmatic. This work provides evidence that downregulation of 11ß-hydroxysteroid dehydrogenase (HSD) type 2, the key enzyme inactivating glucocorticoid activities, insults the pregnant inflammatory milieu by inhibiting the biosynthesis of lipoxin A4 (LXA4), a metabolite of arachidonic acid, leading to an early loss of the pregnancy. Both LXA4 and its biosynthetic enzymes were found to be decreased in women with spontaneous miscarriages and in the murine miscarriage model. Replenishing LXA4 reversed LPS-induced miscarriages in mouse models, whereas blocking LXA4 signaling resulted in miscarriages in the pregnant mice. The protective effect of LXA4 might be explained by LXA4's role in regulating uterine and placental inflammatory factors and mast cells. The underlying molecular mechanism involved miscarriage-inducing infections or stresses that downregulate the expression of 11ß-HSD2, but not 11ß-HSD1, resulting in increases in glucocorticoid activity and decreases in LXA4. Together, these findings suggest that the stress/glucocorticoid/LXA4 axis might be a common pathway through which miscarriages occur.

Innate immune cell-derived microparticles facilitate hepatocarcinoma metastasis by transferring integrin α(M)ß2 to tumor cells.

Mechanisms by which tumor cells metastasize to distant organs still remain enigmatic. Immune cells have been assumed to be the root of metastasis by their fusing with tumor cells. This fusion theory, although interpreting tumor metastasis analogically and intriguingly, is arguable to date. We show in this study an alternative explanation by immune cell-derived microparticles (MPs). Upon stimulation by PMA or tumor cell-derived supernatants, immune cells released membrane-based MPs, which were taken up by H22 tumor cells, leading to tumor cell migration in vitro and metastasis in vivo. The underlying molecular basis was involved in integrin α(M)ß2 (CD11b/CD18), which could be effectively relayed from stimulated innate immune cells to MPs, then to tumor cells. Blocking either CD11b or CD18 led to significant decreases in MP-mediated tumor cell metastasis. This MP-mediated transfer of immune phenotype to tumor cells might also occur in vivo. These findings suggest that tumor cells may usurp innate immune cell phenotypes via MP pathway for their metastasis, providing new insight into tumor metastatic mechanism.

Glucocorticoids sensitize rat placental inflammatory responses via inhibiting lipoxin A4 biosynthesis.

Inflammation dysregulation in placenta is implicated in the pathogenesis of numerous pregnancy complications. Glucocorticoids (GCs), universally considered anti-inflammatory, can also exert proinflammatory actions under some conditions, whereas whether and how GCs promote placental inflammation have not been intensively investigated. In this paper we report the opposing regulation of rat placental inflammation by synthetic GC dexamethasone (Dex). When Dex was subcutaneously injected 1 h after we administered an intraperitoneal lipopolysaccharide (LPS) challenge, neutrophil infiltration and proinflammatory Il1b, Il6, and Tnfa expression in rat placenta were significantly reduced. In contrast, Dex pretreatment for 24 h potentiated rat placental proinflammatory response to LPS and delayed inflammation resolution, which involved MAPKs and NF-kappaB activation. Mechanically, Dex pretreatment promoted 5-lipoxygenase (ALOX5) activation and increased leukotriene B4 production, whereas it inhibited the anti-inflammatory and proresolving lipid mediator lipoxin A4 (LXA4) biosynthesis in rat placenta via downregulating ALOX15 and ALOX15B expression. Moreover, LXA4 supplementation dampened Dex-potentiated placental inflammation and suppressed Dex-mediated ALOX5 activation in vivo and in vitro. Taken together, these findings suggest that GCs exposure could promote placental inflammation initiation and delay resolution via disrupting LXA4 biosynthesis.

Preeclampsia induced by cadmium in rats is related to abnormal local glucocorticoid synthesis in placenta.

BACKGROUND: Cadmium (Cd) is a major environmental pollutant that causes multiple adverse health effects in humans and animals. In this study, we investigated Cd-mediated toxic effects in rats during pregnancy and endocrine intervention in the placenta. METHODS: We exposed pregnant rats to intraperitoneal Cd (CdCl2) at various doses (0, 0.25, and 0.5 mg/kg BW/day) from days 5 to 19 of pregnancy and evaluated the maternal-placental-fetal parameters linked to preeclampsia. We measured the corticosterone level in rat serum and placental tissue by sensitive ELISA and also analyzed the expression of glucocorticoid synthesis enzymes in the placenta. RESULTS: Key features of preeclampsia (PE), including hypertension, proteinuria, glomerular endotheliosis, placental abnormalities and small fetal size, appeared in pregnant rats after injection with 0.5 mg/kg BW/day Cd. The placental corticosterone production and maternal and fetal plasma corticosterone levels were increased in rats treated with 0.5 mg/kg BW/day Cd (P <0.01). The expression of 21-hydroxylase (CYP21) and 11beta-hydroxylase (CYP11B1), enzymes essential for corticosteroid synthesis, were increased in Cd-exposed placenta (P <0.01). 11beta-hydroxysteroid dehydrogenase (11beta-HSD2), a dominant negative regulator of local glucocorticoid levels, was decreased in Cd-exposed placenta (P <0.01). CONCLUSIONS: Our study demonstrates for the first time that changes in placental glucocorticoid synthesis induced by Cd exposure during pregnancy could contribute to preeclamptic conditions in rats.

Lipoxin A4 blocks embryo implantation by controlling estrogen receptor α activity.

Embryo implantation involves a complex regulatory network of steroid hormones, inflammatory cytokines, and immune cells. Lipoxin A4 (LXA4), a biologically active eicosanoid with specific anti-inflammatory and pro-resolving properties, was recently found to be a novel modulator of estrogen receptor α (ERα). In this study, we investigated the potential role of LXA4 in implantation. We found that LXA4 blocked embryo implantation in mice and significantly reduced the expression of inflammatory mediators associated with uterine receptivity and embryo implantation, including corticotropin-releasing factor (CRF), cyclooxygenase 2-derived prostaglandin I2 and prostaglandin E2, leukemia inhibitory factor, and interleukin 6, but this effect was independent of LXA4 receptor. Subsequent investigation revealed enhanced ERα activity in the uteri of LXA4-treated mice during the peri-implantation period. ERα and phosphorylated ERα were significantly increased following LXA4 treatment. Finally, it was demonstrated that the inhibitory effect of LXA4 on embryo implantation was mediated through ERα. In the presence of the ERα antagonist ICI 182 780, LXA4 failed to block embryo implantation. LXA4 also failed to inhibit CRF expression. These results suggested that LXA4 blocks embryo implantation by controlling ERα activity, and this effect appeared to be related to the suppression of the inflammatory microenvironment necessary for implantation.

Depletion of regulatory T cells facilitates growth of established tumors: a mechanism involving the regulation of myeloid-derived suppressor cells by lipoxin A4.

Regulatory T cells (Tregs) are thought to facilitate tumor development by suppressing protective antitumor immune responses. However, recent clinical and laboratory studies show that Tregs are a favorable element against cancer. In this study, we provide evidence that Tregs have both promoting and inhibiting effects on tumors, depending on the stage of tumor development. By using 0.5 mg cyclophosphamide, we constructed a murine liver cancer model in which Tregs were continuously and selectively depleted. Under such conditions, we found that tumor growth was inhibited at early stages but accelerated later on. Analysis of the tumor microenvironment disclosed that long-term Treg depletion by 0.5 mg cyclophosphamide treatment induced Gr-1(+)CD11b(+) myeloid-derived suppressor cells (MDSCs). Ablation of MDSCs by anti-Gr-1 Ab blocked Treg depletion-induced promotion of tumor growth. Furthermore, lipoxygenases 5 and 12, two enzymes participating in the biosynthesis of the lipid anti-inflammatory mediator lipoxin A(4), were upregulated or downregulated by Treg depletion or adoptive transfer. Correspondingly, the levels of lipoxin A(4) were increased or decreased. Lipoxin A(4) thus regulated the induction of MDSCs in response to Treg depletion. These findings suggest that Tregs may play different roles at different stages of tumor growth: promoting early and inhibiting late tumor growth. Our study also suggests that the interplay among Tregs, MDSCs, and lipoxin A(4) tunes the regulation of tumor-associated inflammation.

Tea and tea drinking: China's outstanding contributions to the mankind.

BACKGROUND: Tea trees originated in southwest China 60 million or 70 million years ago. Written records show that Chinese ancestors had begun drinking tea over 3000 years ago. Nowadays, with the aging of populations worldwide and more people suffering from non-communicable diseases or poor health, tea beverages have become an inexpensive and fine complementary and alternative medicine (CAM) therapy. At present, there are 3 billion people who like to drink tea in the world, but few of them actually understand tea, especially on its development process and the spiritual and cultural connotations. METHODS: We searched PubMed, Google Scholar, Web of Science, CNKI, and other relevant platforms with the key word "tea", and reviewed and analyzed tea-related literatures and pictures in the past 40 years about tea's history, culture, customs, experimental studies, and markets. RESULTS: China is the hometown of tea, tea trees, tea drinking, and tea culture. China has the oldest wild and planted tea trees in the world, fossil of a tea leaf from 35,400,000 years ago, and abundant tea-related literatures and art works. Moreover, tea may be the first Chinese herbal medicine (CHM) used by Chinese people in ancient times. Tea drinking has many benefits to our physical health via its antioxidant, anti-inflammatory, immuno-regulatory, anticancer, cardiovascular-protective, anti-diabetic, and anti-obesity activities. At the moment, COVID-19 is wreaking havoc across the globe and causing severe damages to people's health and lives. Tea has anti-COVID-19 functions via the enhancement of the innate immune response and inhibition of viral growth. Besides, drinking tea can allow people to acquire a peaceful, relaxed, refreshed and cheerful enjoyment, and even longevity. According to the meridian theory of traditional Chinese medicine, different kinds of tea can activate different meridian systems in the human body. At present, black tea (fermented tea) and green tea (non-fermented tea) are the most popular in the world. Black tea accounts for over 90% of all teas sold in western countries. The world's top-grade black teas include Qi Men black in China, Darjeeling and Assam black tea in India, and Uva black tea in Sri Lanka. However, all top ten famous green teas in the world are produced in China, and Xi Hu Long Jing tea is the most famous among all green teas. More than 700 different kinds of components and 27 mineral elements can be found in tea. Tea polyphenols and theaflavin/thearubigins are considered to be the major bioactive components of black tea and green tea, respectively. Overly strong or overheated tea liquid should be avoided when drinking tea. CONCLUSIONS: Today, CAM provides an array of treatment modalities for the health promotion in both developed and developing countries all over the world. Tea drinking, a simple herb-based CAM therapy, has become a popular man-made non-alcoholic beverage widely consumed worldwide, and it can improve the growth of economy as well. Tea can improve our physical and mental health and promote the harmonious development of society through its chemical and cultural elements.

Novel biphasic role of LipoxinA(4) on expression of cyclooxygenase-2 in lipopolysaccharide-stimulated lung fibroblasts.

Fibroblasts are important to host defence and immunity, can also as initiators of inflammation as well. As the endogenous "braking signal", Lipoxins can regulate anti-inflammation and the resolution of inflammation. We investigated the effect of lipoxinA(4) on the expression of cyclooxygenase-2 in lipopolysaccharide-stimulated lung fibroblasts. We demonstrated that the expression of cyclooxygenase-2 protein was significantly increased and peaked initially at 6 hours, with a second increase, with maximal levels occurring 24 hours after lipopolysaccharide challenge. ProstaglandinE(2) levels also peaked at 6 hours, and prostaglandinD(2) levels were increased at both 6 and 24 hours. Exogenous lipoxinA(4) inhibited the first peak of cyclooxygenase-2 expression as well as the production of prostaglandinE(2) induced by lipopolysaccharide in a dose-dependent manner. In contrast, exogenous lipoxinA(4) increased the second peak of cyclooxygenase-2 expression as well as the production of prostaglandinD(2) induced by lipopolysaccharide in a dose-dependent manner. LipoxinA(4) receptor mRNA expression was markedly stimulated by lipopolysaccharide but inhibited by lipoxinA(4). We present evidence for a novel biphasic role of lipoxinA(4) on the expression of cyclooxygenase-2 in lipopolysaccharide-stimulated lung fibroblasts, whereby LXA(4) has an anti-inflammatory and proresolving activity in lung fibroblasts following LPS stimulation.

Lipoxins: a novel regulator in embryo implantation.

Embryo implantation is essential for mammalian pregnancy, which involves intricate cross-talk between the blastocyst and the maternal endometrium. Recent advances have identified various molecules crucial to implantation and endometrial receptivity, including leukemia inhibitory factor, calcitonin, and homeobox A10. There is a close relationship between implantation and inflammation. Lipoxins, important in the resolution of inflammation, may be a potential regulator in implantation. Here we discuss the hypothesis that lipoxins may work as a novel regulator in embryo implantation and the possible molecular mechanisms.

Effect of lipoxin A4 on lipopolysaccharide-induced endothelial hyperpermeability.

Excessive oxidative stress, decreased antioxidant capacity, and enhanced cellular calcium levels are initial factors that cause endothelial cell (EC) hyperpermeability, which represents a crucial event in the pathogenesis of pre-eclampsia. Lipoxin A4 (LXA4) strongly attenuated lipopolysaccharide (LPS)-induced hyperpermeability through maintaining the normal expression of VE-cadherin and â-catenin. This effect was mainly mediated by a specific LXA4 receptor. LXA4 could also obviously inhibit LPS-induced elevation of the cellular calcium level and up-regulation of the transient receptor potential protein family C 1, an important calcium channel in ECs. At the same time, LXA4 strongly blocked LPS-triggered reactive oxidative species production, while it promoted the expression of the NF-E2 related factor 2 (Nrf2) protein. Our findings demonstrate that LXA4 could prevent the EC hyperpermeability induced by LPS in human umbilical vein endothelial cells (HUVECs), under which the possible mechanism is through Nrf2 as well as Ca2+-sensitive pathways.

[Effect of lipoxin A(4) on lipopolysaccharide-induced endothelial hyperpermeability in human umbilical vein endothelial cell].

OBJECTIVE: To explore whether lipoxin A(4) (LXA(4))could prevent lipopolysaccharide (LPS)-induced human umbilical vein endothelial cells (HUVEC) monolayer hyperpermeability and its possible mechanism. METHODS: Human umbilical cords were obtained from women with normal pregnancy immediately after delivery from Tongji Hospital Affiliated of Tongji Medical College. Primary HUVEC were isolated from umbilical veins and subcultured, then, HUVEC were divided into four groups:control group; LPS group (10 mg/L of LPS); LPS + LXA(4) group(10 mg/L of LPS and 100 nmol/L of LXA(4)); LPS + LXA(4) + BOC-2 group [10 µmol/L of BOC-2, an effective antagonist of formyl peptide receptor like 1 (FPRL-1)]. All expriments were performed after cells were treated for 24 hours. Endothelial permeability was measured by fluorescein isothiocyan-ate labelled bovine serum albumin (FITC-BSA) clearance across the monolayer; tumor necrosis factor α (TNF-α) mRNA and secretion were detected by reverse transcriplase (RT)-PCR and ELISA assay respectively, and nuclear factor κB (NF-κB) protein change was determined by western blot. RESULTS: (1) LPS induced a significant increase in the permeability [Pa value of LPS group was (183.1 ± 1.7)%], while co-administrating with LXA(4) obviously attenuated this LPS-induced hyperpermeability, Pa value of LPS + LXA(4) group was (103.1 ± 2.2)%, LPS + LXA(4) + BOC-2 group was (162.2 ± 2.8)%, control group was 100%, the permeability of HUVEC monolayer was significantly increased by LPS which was (83.1 ± 1.7)% of control (P < 0.01), however, it was notably inhibited by LXA(4) (P < 0.05); the blockade of FPRL-1 could attenuate the effect of LXA(4), that is, there was no difference between the LPS + LXA(4) + BOC-2 group and the LPS group. (2) After treatment with different concentration of LPS(0, 0.1, 1, 10 mg/L), the mRNA expressions of TNF-α were increased (1.11 ± 0.11, 1.27 ± 0.03, 1.60 ± 0.06, 1.82 ± 0.04, respectively), compared with the control group, at the concentration of 1, 10 mg/L LPS, the difference was statistically significant (P < 0.05). (3) The increased levels of NF-κB and inflammatory mediator TNF-α in the LPS group were both inhibited by LXA(4). Levels of NF-κB protein and TNF-α mRNA secretion in LPS treated group (0.53 ± 0.06 and 0.81 ± 0.09, respectively) were both inhibited by LXA(4)(0.19 ± 0.05 and 0.41 ± 0.07, respectively, and both had significant difference, P < 0.05). (4) Levels of TNF-α in HUVEC culture medium of LPS group [(31.94 ± 0.01) ng/L] was significantly higher than the control group [(18.17 ± 0.03) ng/L, P < 0.05], LPS + LXA(4) group [(15.72 ± 0.07) ng/L] was significantly lower than the LPS group (P < 0.05). CONCLUSION: Our findings demonstrated that LXA(4) could prevent the endothelial cell hyperpermeability induced by LPS in HUVEC under which the possible mechanism was through inhibiting the expression of NF-κB and its related cytokines through receptor-dependent.

Microparticles mediate enzyme transfer from platelets to mast cells: a new pathway for lipoxin A4 biosynthesis.

The inflammation-resolving lipid mediator lipoxin A4 (LXA4), which is derived from arachidonic acid in the context of inflammation, can be generated physiologically in vivo. However, the mechanism of physiologic formation of LXA4 remains elusive. In this report, we provide evidence that platelet-derived microparticles contain lipoxygenase 12 (12-LO) protein and act as a mediator in transferring 12-LO to mast cells, leading to the production of LXA4 by mast cells. Absence of either leukotriene, the precursor for LXA4, in mast cells or 12-LO in microparticles abolished LXA4 production. Using a mouse model, we demonstrated that platelet-derived microparticles were taken up by peritoneal mast cells in vivo and triggered LXA4 production. We also found that similar to LXA4, platelet-derived microparticles attenuated LPS- or dextran sulfate sodium-induced inflammation by regulating inflammatory cytokines. Together, these data suggest a critical role of platetlet-derived microparticles as a signal mediator, at least in LXA4 production, resulting in significant immunoregulatory consequences.

[Effect of lipoxin A(4) on lipopolysaccharide-induced oxidant stress in human umbilical vein endothelial cells].

OBJECTIVE: To explore the effects of lipoxin A(4) (LXA(4)) on lipopolysaccharide (LPS)-induced oxidative stress in human umbilical veins endothelial cells (HUVEC) and the possible mechanism. METHODS: Neonatal umbilical cords were obtained from normal term pregnant women with cesarean section within 4 hours and then were used to isolate HUVEC for subculture. HUVEC were divided into four groups:control group; LPS group (10 µg/ml of LPS); LPS + LXA(4) group (10 µg/ml of LPS and 100 nmol/L of LXA(4)); LXA(4) group (100 nmol/L of LXA(4)). All expriments were performed after cells treated for 12 and 24 hours respectively. Immunofluorescence was used to detect the expression of VIII foctor and nuclear translocation of nuclear factor-erythroid-2-related factor 2 (Nrf2); the mRNA expression of Nrf2, heme oxygenase 1 (HO-1) and reduced form of nicotinamide-adenine dinucleotide quinone oxidoreductase-1 (NQO1) were evaluated by reverse transcription-PCR. RESULTS: (1) The flavovirens fluorescence was observed in the cytoplasm under fluorescence microscope, which confirmed the existence of VIII factor which specifically expressed in endothelial cells, especially in HUVEC. (2) Immunofluorescent results showed that in control group, Nrf2 protein expressed in the cytosol rather than in the nucleus. In LPS group, the expression of Nrf2 protein obviously increased in the nucleus while decreased in the cytosol after 12 hours. However, after LPS treatment for 24 hours, Nrf2 expression reduced in the cytosol and nucleus. In co-treatment with LPS and LXA(4) group, the expression of Nrf2 protein was much higher than that in LPS group after 12 hours or 24 hours. Furthermore, Nrf2 protein also mostly expressed in the cytosol in LXA(4) group. (3) After stimulation for 12 hours, compared with control group, the gene expression of Nrf2 and HO-1 were significantly enhanced in LPS group (0.581 ± 0.019 and 0.081 ± 0.009, P < 0.05) and in LPS + LXA(4) group (0.692 ± 0.048 and 0.136 ± 0.018, P < 0.05), the level of NQO1 mRNA in LPS group and LPS + LXA(4) group were 0.381 ± 0.009 (P > 0.05) and 0.574 ± 0.034 (P < 0.05). After treatment for 24 hours, compared with control goup, the gene expressions of Nrf2 and NQO1 were down-regulated in LPS group (0.180 ± 0.017 and 0.472 ± 0.064, P < 0.05). But in LPS + LXA(4) group the expression of Nrf2 and NQO1 were upregulated (0.532 ± 0.051 and 0.830 ± 0.068, P < 0.05, compared with treatment for LPS group). The mRNA expressions of Nrf2, HO-1 and NQO1 were increased in LPS + LXA(4) group compared with LPS group (P < 0.05). In addition, there was no markedly difference in the expressions of Nrf2, HO-1 and NQO1 between control and LXA(4) group after 12 hours and 24 hours (P > 0.05). CONCLUSION: Through activating nuclear translocation of Nrf2 protein from cytoplasm, LXA(4) upregulates the Nrf2 downstream enzymes, such as NQO1 and HO-1 to protect HUVEC against the oxidative stress induced by LPS.

Glucocorticoid Exposure Induces Preeclampsia via DampeningLipoxin A4, an Endogenous Anti-Inflammatory and Proresolving Mediator.

The pathogenesis of preeclampsia (PE) involves several pathophysiological processes that may be affected by glucocorticoid (GC). We confirmed previously that GC exposure could result in PE, while PE is linked to a deficiency of lipoxin A4 (LXA4), an endogenous dual anti-inflammatory and proresolving mediator. The present study was to investigate whether GC exposure induces PE via dampening LXA4. In the study, cortisol levels of PE women were higher than those of normal pregnancies, LXA4 levels were downregulated in both PE patients and GC-mediated PE rats, and leukotriene B4 (LTB4) levels were upregulated in both PE patients and GC- mediated PE rats. Moreover, cortisol levels were negatively correlated to LXA4 levels, while positively correlated to LTB4 levels in PE patients. Mechanically, GC downregulated LXA4 via disturbing its biosynthetic enzymes, including ALOX15, ALOX5B and ALOX5, especially activating ALOX5, the key enzyme for class switching between LXA4 and LTB4. Importantly, replenishing LXA4 could ameliorate PE-related symptoms and placental oxidative stress in PE rat model induced by GC. Moreover, LXA4 could inhibit GC-mediated ALOX5 activation and LTB4 increase, and also suppress 11ß-HSD2 expression and corticosterone upregulation. The protective actions of LXA4 might be explained by its roles in antagonizing the adverse effects of GC on trophoblast development. Together, our findings indicate that GC exposure could contribute to PE through dampening LXA4, and GC/LXA4 axis may represent a common pathway through which PE occurs.

Hesperetin attenuated acetaminophen-induced hepatotoxicity by inhibiting hepatocyte necrosis and apoptosis, oxidative stress and inflammatory response via upregulation of heme oxygenase-1 expression.

Acetaminophen (APAP) is a common antipyretic and analgesic drug, but its overdose can induce acute liver failure with lack of effective therapies. Hesperetin, a dihydrogen flavonoid compound, has been revealed to exert multiple pharmacological activities. Here, we explored the protective effects and mechanism of hesperetin on APAP-induced hepatotoxicity. The results showed that pretreatment with hesperetin dose-dependently attenuated APAP-induced acute liver injury in mice, as measured by alleviated serum enzymes activities, hepatic pathological damage and apoptosis. Moreover, hesperetin mitigated APAP-induced oxidative stress and inflammatory response in mice by inhibiting oxidative molecules but increasing antioxidative molecules production, reducing inflammatory cells infiltration and proinflammatory cytokines production, blocking Toll-like receptor (TLR)-4 signal activation. In vitro experiment indicated that hesperetin dose-dependently inhibited APAP-primed cytotoxicity, apoptosis, and reactive oxygen species (ROS) in murine AML12 hepatocytes. Notably, hesperetin up-regulated expression of heme oxygenase-1 (HO-1) mRNA and protein in the liver of mice and AML12 cells exposed to APAP. Furthermore, knockdown of HO-1 by adenovirus-mediated HO-1 siRNA reverted these beneficial effects of hesperetin on APAP-induced hepatocytotoxicity as well as ROS and inflammatory response in vivo and in vitro. These findings demonstrated that hesperetin exerted a protective prophylaxis on APAP-induced acute liver injury by inhibiting hepatocyte necrosis and apoptosis, oxidative stress and inflammatory response via up-regulating HO-1 expression.

Lipoxin A4 suppresses angiotensin II type 1 receptor autoantibody in preeclampsia via modulating caspase-1.

Preeclampsia (PE) remains a leading cause of maternal and neonatal morbidity and mortality. Numerous studies have shown that women with PE develop autoantibody, termed angiotensin II type 1 receptor autoantibody (AT1-AA), and key features of the disease result from it. Emerging evidence has indicated that inflammatory cell necrosis, such as pyroptosis, could lead to autoantigen exposure and stimulate autoantibody production. Caspase-1, the central enzyme of inflammasome and key target of pyroptosis, may play roles in AT1R exposure and AT1-AA production. Exploring endogenous regulator that could inhibit AT1-AA production by targeting pyroptosis will be essential for treating PE. Lipoxin A4 (LXA4), endogenous dual anti-inflammatory and proresolving lipid mediator, may inhibit AT1-AA production via modulating caspase-1. Thus, we explore whether caspase-1 is essential for AT1-AA production and LXA4 inhibits AT1-AA via modulating caspase-1. PE patients and mice developed AT1-AA associated with caspase-1 activation. Caspase-1 deletion leaded to AT1-AA decrease in PE mice. Consistent with these findings, we confirmed caspase-1 activation, trophoblast pyroptosis and AT1R exposure in PE mice and trophoblast model, while caspase-1 deficiency showed decreased trophoblast pyroptosis and AT1R exposure in vitro and in vivo. Interestingly, LXA4 could suppress AT1-AA production via regulating caspase-1 as well as enhancing phagocytosis of dead trophoblasts by macrophages. These results suggest that caspase-1 promotes AT1-AA production via inducing trophoblast pyroptosis and AT1R exposure, while LXA4 suppresses AT1-AA production via modulating caspase-1, supporting caspase-1 serving as a therapeutic target for attenuating AT1-AA and LXA4 protecting patients from AT1-AA and PE.

Effects of exogenous annexin-1 on lipopolysaccharide-induced proliferation and reactive oxygen species production partially through modulation of CRAC channels but independent of NF-kappaB pathway.

OBJECTIVE: To investigate the effects of exogenous annexin-1 (ANXA1) on lipopolysaccharide(LPS)-induced proliferation, reactive oxygen species (ROS) production, and calcium signal transduction in RAW264.7 macrophages. METHODS: RAW264.7 macrophages were treated with or without LPS in the absence or presence of ANXA1. The proliferation effects were detected by Cell Counting Kit-8 assay. ROS were quantified by flow cytometry and fluorescence microscopy. Intracellular Ca(2+) concentration ([Ca(2+)](i)) was analyzed by laser confocal scanning microscopy. IkappaBalpha degradation and NF-kappaB translocation were tested by Western blot. RESULTS: Exogenous ANXA1 inhibited LPS-induced proliferation and ROS production in a dose-dependent manner. LPS evoked [Ca(2+)](i) increase through CRAC channels, and ANXA1 suppressed LPS-induced [Ca(2+)](i) increase in a dose-dependent manner. The CRAC channels were associated with LPS-induced proliferation and ROS production. Exogenous ANXA1 had no effect on LPS-induced IkappaB degradation and NF-kappaB translocation. CONCLUSIONS: ANXA1 inhibited LPS-induced proliferation and ROS production in RAW264.7 macrophages partially through modulation of CRAC channels but independent of the NF-kappaB pathway.

Lipoxin A(4) inhibited hepatocyte growth factor-induced invasion of human hepatoma cells.

AIM: Inflammation is a critical component of tumor progression. Lipoxin A(4) (LXA(4)) has been approved for potent anti-inflammatory properties. Recently, it was reported that LXA(4) repressed the expression and activity of cyclooxygenase-2 (COX-2), which is essential for invasion. However, there are few reports dealing with its effects on cancer. To explore whether LXA(4) regulate invasion, the effects of LXA(4) and its receptor agonist BML-111 on hepatocyte growth factor (HGF)-induced invasion of hepatoma cells and the possible mechanisms were researched. METHODS: Lipoxin A(4) receptor (ALX) expression in HepG2 cells were measured through reverse transcription polymerase chain reaction and western blot. Cytotoxicity of LXA(4) and BML-111 to HepG2 cells was detected by MTT and ((3)H)-TdR incorporation assay. Cell migration and invasion assays were performed using a Boyden chemotaxis chamber. COX-2 expression was detected by real-time polymerase chain reaction and western blot, respectively. Moreover, the expressions of matrix metalloproteinases (MMP)-2, MMP-9, IkappaBalpha and nuclear factor-kappaB (NF-kappaB) p65 were observed via western blot, and NF-kappaB transcriptional activity was tested by transfections and luciferase activities assay. RESULTS: ALX expression was detected in HepG2 cells, and suitable concentrations of LXA(4) and BML-111 had no cytotoxicity to cells. LXA(4) and BML-111 inhibited HGF-induced migration and invasion; downregulated COX-2, MMP-2 and -9; restrained HGF-induced IkappaBalpha degradation, NF-kappaB translocation and the transcriptional activity of NF-kappaB in HepG2 cells. Furthermore, exogenous PGE2 could reverse the inhibitory effects of LXA(4) also BML-111 on HGF-induced invasion and migration partially. CONCLUSION: LXA(4) inhibited HGF-induced invasion of HepG2 cells through NF-kappaB/COX-2 signaling pathway partially.