Ox-LDL-induced CD80+ macrophages expand pro-atherosclerotic NKT cells via CD1d in atherosclerotic mice and hyperlipidemic patients.

Atherosclerosis is an inflammatory disease of blood vessels involving the immune system. Natural killer T (NKT) cells, as crucial components of the innate and acquired immune systems, play critical roles in the development of atherosclerosis. However, the mechanism and clinical relevance of NKT cells in early atherosclerosis are largely unclear. The study investigated the mechanism influencing NKT cell function in apoE deficiency-induced early atherosclerosis. Our findings demonstrated that there were higher populations of NKT cells and interferon-gamma (IFN-γ)-producing NKT cells in the peripheral blood of patients with hyperlipidemia and in the aorta, blood, spleen, and bone marrow of early atherosclerotic mice compared with the control groups. Moreover, we discovered that the infiltration of CD80+ macrophages and CD1d expression on CD80+ macrophages in atherosclerotic mice climbed remarkably. CD1d expression increased in CD80+ macrophages stimulated by oxidized low-density lipoprotein (ox-LDL) ex vivo and in vitro. Ex vivo coculture of macrophages with NKT cells revealed that ox-LDL-induced CD80+ macrophages presented lipid antigen α-Galcer (alpha-galactosylceramide) to NKT cells via CD1d, enabling NKT cells to express more IFN-γ. Furthermore, a greater proportion of CD1d+ monocytes and CD1d+CD80+ monocytes were found in peripheral blood of hyperlipidemic patients compared with that of healthy donors. Positive correlations were found between CD1d+CD80+ monocytes and NKT cells or IFN-γ+ NKT cells in hyperlipidemic patients. Our findings illustrated that CD80+ macrophages stimulated NKT cells to secrete IFN-γ via CD1d-presenting α-Galcer, which may accelerate the progression of early atherosclerosis. Inhibiting lipid antigen presentation by CD80+ macrophages to NKT cells may be a promising immune target for the treatment of early atherosclerosis.NEW & NOTEWORTHY This work proposed the ox-LDL-CD80+ monocyte/macrophage-CD1d-NKT cell-IFN-γ axis in the progression of atherosclerosis. The proinflammatory IFN-γ+ NKT cells are closely related to CD1d+CD80+ monocytes in hyperlipidemic patients. Inhibiting CD80+ macrophages to present lipid antigens to NKT cells through CD1d blocking may be a new therapeutic target for atherosclerosis.

Novel Effect of p-Coumaric Acid on Hepatic Lipolysis: Inhibition of Hepatic Lipid-Droplets.

p-coumaric acid (p-CA), a common plant phenolic acid with multiple bioactivities, has a lipid-lowering effect. As a dietary polyphenol, its low toxicity, with the advantages of prophylactic and long-term administration, makes it a potential drug for prophylaxis and the treatment of nonalcoholic fatty liver disease (NAFLD). However, the mechanism by which it regulates lipid metabolism is still unclear. In this study, we studied the effect of p-CA on the down-regulation of accumulated lipids in vivo and in vitro. p-CA increased a number of lipase expressions, including hormone-sensitive lipase (HSL), monoacylglycerol lipase (MGL) and hepatic triglyceride lipase (HTGL), as well as the expression of genes related to fatty acid oxidation, including long-chain fatty acyl-CoA synthetase 1 (ACSL1), carnitine palmitoyltransferase-1 (CPT1), by activating peroxisome proliferator-activated receptor α, and γ (PPARα and γ). Furthermore, p-CA promoted adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) phosphorylation and enhanced the expression of the mammalian suppressor of Sec4 (MSS4), a critical protein that can inhibit lipid droplet growth. Thus, p-CA can decrease lipid accumulation and inhibit lipid droplet fusion, which are correlated with the enhancement of liver lipases and genes related to fatty acid oxidation as an activator of PPARs. Therefore, p-CA is capable of regulating lipid metabolism and is a potential therapeutic drug or health care product for hyperlipidemia and fatty liver.

Sialic acids promote macrophage M1 polarization and atherosclerosis by upregulating ROS and autophagy blockage.

Accumulating evidence suggests that sialic acids is closely related to atherosclerosis. However, the effects and underlying mechanisms of sialic acids in atherosclerosis have been not defined. Macrophages are one of the most important cells during plaque progression. In this study, we investigated the role of sialic acids in the M1 macrophage polarization and pathogenesis of atherosclerosis. Here we found that sialic acids can promote the polarization of RAW264.7 cells to the M1 phenotype, thereby promoting the expression of proinflammatory cytokines in vitro. The proinflammatory effect of sialic acids may result from the inhibition of LKB1-AMPK-Sirt3 signaling pathway to upregulate intracellular ROS and impairing autophagy-lysosome system to block autophagic flux. In the APOE-/- mice, sialic acids in plasma increased during the development of atherosclerosis. Moreover, exogenous supplement of sialic acids can promote plaque progression in aortic arch and aortic sinus being accompanied by the differentiation of macrophages into M1 type in peripheral tissues. These studies demonstrated that sialic acids can promote macrophage polarization toward the M1 phenotype to accentuate atherosclerosis via inducing mitochondrial ROS and blocking autophagy, thus providing clue to a novel therapeutic strategy for atherosclerosis.

The role of UNC5b in ox-LDL inhibiting migration of RAW264.7 macrophages and the involvement of CCR7.

The formation of macrophage foam cells by ingesting ox-LDL and focal retention in the subendothelial space are the hallmarks of the early atherosclerotic lesion. The C-C chemokine receptor type 7 (CCR7) is positively correlated with the macrophage migration. But the mechanism of CCR7 regulation is not fully clearness. In the present study, we demonstrates that expression in UNC5b and netrin-1 was enhanced in respond to ox-LDL in Raw264.7 macrophage and associated with decreasing cell migration. Interestingly, it was found that ox-LDL significantly downregulate CCR7 gene expression. The expression of CCR7 in mRNA and protein levels were decreased in ox-LDL treated Raw264.7 macrophage when we over expression of UNC5b with pcDNA3.1-UNC5b plasmid. We got the inverse results after silence UNC5b gene with siUNC5b. Meanwhile, the data show that in ox-LDL inducement, UNC5b down-regulated CCR7, and then inhibited macrophage migration. This novel phenomenon is of a crucial highlights to understand deeply the pathogenesis of atherosclerosis. The molecular mechanism of CCR7 regulation deserves intensive study.

Mechanism underlying berberine's effects on HSP70/TNFα under heat stress: Correlation with the TATA boxes.

Heat stress can stimulate an increase in body temperature, which is correlated with increased expression of heat shock protein 70 (HSP70) and tumor necrosis factor α (TNFα). The exact mechanism underlying the HSP70 and TNFα induction is unclear. Berberine (BBR) can significantly inhibit the temperature rise caused by heat stress, but the mechanism responsible for the BBR effect on HSP70 and TNFα signaling has not been investigated. The aim of the present study was to explore the relationship between the expression of HSP70 and TNFα and the effects of BBR under heat conditions, using in vivo and in vitro models. The expression levels of HSP70 and TNFα were determined using RT-PCR and Western blotting analyses. The results showed that the levels of HSP70 and TNFα were up-regulated under heat conditions (40 °C). HSP70 acted as a chaperone to maintain TNFα homeostasis with rising the temperature, but knockdown of HSP70 could not down-regulate the level of TNFα. Furthermore, TNFα could not influence the expression of HSP70 under normal and heat conditions. BBR targeted both HSP70 and TNFα by suppressing their gene transcription, thereby decreasing body temperature under heat conditions. In conclusion, BBR has a potential to be developed as a therapeutic strategy for suppressing the thermal effects in hot environments.

TRPM8 in the negative regulation of TNFα expression during cold stress.

Transient Receptor Potential Melastatin-8 (TRPM8) reportedly plays a fundamental role in a variety of processes including cold sensation, thermoregulation, pain transduction and tumorigenesis. However, the role of TRPM8 in inflammation under cold conditions is not well known. Since cooling allows the convergence of primary injury and injury-induced inflammation, we hypothesized that the mechanism of the protective effects of cooling might be related to TRPM8. We therefore investigated the involvement of TRPM8 activation in the regulation of inflammatory cytokines. The results showed that TRPM8 expression in the mouse hypothalamus was upregulated when the ambient temperature decreased; simultaneously, tumor necrosis factor-alpha (TNFα) was downregulated. The inhibitory effect of TRPM8 on TNFα was mediated by nuclear factor kappa B (NFκB). Specifically, cold stress stimulated the expression of TRPM8, which promoted the interaction of TRPM8 and NFκB, thereby suppressing NFκB nuclear localization. This suppression consequently led to the inhibition of TNFα gene transcription. The present data suggest a possible theoretical foundation for the anti-inflammatory role of TRPM8 activation, providing an experimental basis that could contribute to the advancement of cooling therapy for trauma patients.

Mitochondria play an important role in the cell proliferation suppressing activity of berberine.

After being studied for approximately a century, berberine (BBR) has been found to act on various targets and pathways. A great challenge in the pharmacological analysis of BBR at present is to identify which target(s) plays a decisive role. In the study described herein, a rescue experiment was designed to show the important role of mitochondria in BBR activity. A toxic dose of BBR was applied to inhibit cell proliferation and mitochondrial activity, then α-ketobutyrate (AKB), an analogue of pyruvate that serves only as an electron receptor of NADH, was proven to partially restore cell proliferation. However, mitochondrial morphology damage and TCA cycle suppression were not recovered by AKB. As the AKB just help to regenerate NAD+, which is make up for part function of mitochondrial, the recovered cell proliferation stands for the contribution of mitochondria to the activity of BBR. Our results also indicate that BBR suppresses tumour growth and reduces energy charge and mitochondrial DNA (mtDNA) copy number in a HepG2 xenograft model. In summary, our study suggests that mitochondria play an important role in BBR activity regarding tumour cell proliferation and metabolism.

Brazilein inhibits neuronal inflammation induced by cerebral ischemia and oxygen-glucose deprivation through targeting NOD2 expression.

Brazilein is reported to have immunosuppressive effect on cardiovascular and cerebral-vascular diseases. The essential roles of innate immunity in cerebral ischemia are increasingly identified, but no studies concerning the influence of brazilein on the innate immunity receptors have been reported. The present study was designed to investigate the regulation of NOD2 (Nucleotide-binding oligomerization domain-containing protein 2) by brazilein for its protection of neuron in cerebral ischemia in vivo and oxygen-glucose deprivation in vitro. The results showed that brazilein could reverse the elevated expression of NOD2 and TNFα (tumor necrosis factor alpha) elicited by cerebral ischemia and reperfusion. This reduction could also be detected in normal mice and C17.2 cells, indicating that this suppressive effect of brazilein was correlated with NOD2. The results from GFP reporter plasmid assay suggested brazilein inhibited NOD2 gene transcription. In conclusion, brazilein could attenuate NOD2 and TNFα expression in cerebral ischemia and NOD2 may be one possible target of brazilein for its immune suppressive effect in neuro-inflammation.

[Berberine action targets and its absorption behavior：how to use old drug for new mechanisms].

A variety of pharmacological effects of berberine (BBR) are constantly being discovered with the deepening of BBR research. What followed is how to rationally use the drug according to these new pharmacological effects. Because of some cardiac toxicity and poor oral absorption, conflicts may arise between improving the bioavailability and controlling the toxicity of BBR. Meanwhile some new therapeutic uses of BBR, such as hypolipidemia, hypoglycemia as well as prevention and treatment of neurodegenerative diseases, need long-termoral administration, thereby may lead to alteration of intestinal flora and potentially affect body's other physiological functions. Based on the stated targets of BBR and related pharmaceutical properties, comprehensive analysis of these issues was conducted in this study. Some suggestions were presented below：the effect of long-term oral administration on body function, especially the intestinal flora, needs to be further investigated; risks shall be considered in changing the composition of the formulation to improve the absorption rate of oral administration; for the medication with higher concentration demand (such as anti-cancer), targeted drug-delivery is worthy to be considered.

Inhibition of retinoblastoma mRNA degradation through Poly (A) involved in the neuroprotective effect of berberine against cerebral ischemia.

Berberine is one kind of isoquinoline alkaloid with anti-apoptotic effects on the neurons suffering ischemia. To address the explanation for these activities, the berberine-induced cell cycle arrest during neurons suffering ischemia/reperfusion had been studied in the present study. According to the in vitro neurons with oxygen-glucose deprivation and in vivo ICR mice with cerebral ischemia/reperfusion, it was found that berberine could protect the mRNA of retinoblastoma (Rb) from degradation through its function on the poly(A) tail. The prolonged half-life of retinoblastoma 1 (gene of Rb, RB1) mRNA level secures the protein level of retinoblastoma, which facilitates cell cycle arrest of neurons in the process of ischemia/reperfusion and subsequently avoids cells entering in the apoptotic process. The poly(A) tail of RB1 mRNA, as a newly identified target of berberine, could help people focus on the interaction between berberine and mRNA to further understand the biological activities and functions of berberine.

Effect of berberine on cell cycle arrest and cell survival during cerebral ischemia and reperfusion and correlations with p53/cyclin D1 and PI3K/Akt.

Berberine acted as a natural medicine with multiple pharmacological activities. In the present study, we examined the effect of berberine against cerebral ischemia damage from cell cycle arrest and cell survival. Oxygen-glucose deprivation of PC12 cells and primary neurons, and carotid artery ligation in mice were used as in vitro and in vivo cerebral ischemia models. We found that the effect of berberine on cell cycle arrest during ischemia was mediated by decreased p53 and cyclin D1, increased phosphorylation of Bad (higher expression of p-Bad and higher ratio of p-Bad to Bad) and decreased cleavage of caspase 3. Meanwhile, berberine activated the PI3K/Akt pathway during the reperfusion, especially the phosphor-activation of Akt, to promote the cell survival. The neural protective effect of berberine was remained in the presence of inhibitor of mitogen-activated protein/extracellular signal-regulated kinase (MEK), but was suppressed by the inhibitors of PI3K and Akt. We demonstrated that berberine induced cell cycle arrest and cell survival to resist cerebral ischemia injury.

Novel effect of berberine on thermoregulation in mice model induced by hot and cold environmental stimulation.

The purpose of this study was to assess the effects of berberine (BBR) on thermoregulation in mice exposed to hot (40°C) and cold (4°C) environmental conditions. Four groups of mice were assembled with three different dosages of BBR (0.2, 0.4, and 0.8 mg/kg) and normal saline (control). In room temperature, our largest dosage of BBR (0.8 mg/kg) can reduce rectal temperatures (Tc) of normal mice. In hot conditions, BBR can antagonize the increasing core body temperature and inhibit the expression of HSP70 and TNFα in mice; conversely, in cold conditions, BBR can antagonize the decreasing core body temperature and enhance the expression of TRPM8. This study demonstrates the dual ability of BBR in maintaining thermal balance, which is of great relevance to the regulation of HSP70, TNFα and TRPM8.

Role of baicalin in regulating Toll-like receptor 2/4 after ischemic neuronal injury.

BACKGROUND: Baicalin has a significant anti-inflammation effect and is widely used in the clinical treatment of stroke. Most of the studies of Toll-like receptor 2/4 (TLR2/4) during cerebral ischemia had defined their specific expressions in microglia in hippocampus tissue. To explore the targets of baicalin in stroke, we detected the expressions of TLR2/4 in vitro/vivo. METHODS: By constructing a cerebral ischemia-reperfusion model in vivo and glucose oxygen deprivation model, we successfully induced neuron damage, then added baicalin and detected expressions of TLR2/4, nuclear factor-kB (NF-kB), tumor necrosis factor-alpha (TNFα), and interleukin-1ß (IL-1ß) in mRNA level and protein level. RESULTS: We found distinct upregulations of TLR2/4 and TNFα in both mRNA level and protein level in PC12 cells and primary neurons. Moreover, TLR2/4 and TNFα expressions were significantly higher in mice hippocampus treated with cerebral ischemia-reperfusion. Baicalin could downregulate the expressions of TLR2/4 and TNFα in the damaged cells and mice hippocampus effectively. CONCLUSIONS: Neurons could respond to the damage and activate the related signal pathway directly. TLR2/4 responsed to the damage and sent the signal to downstream factor TNFα through activating NF-kB. Baicalin could inhibit the inflammatory reaction in neuron damage and TLR might be its targets, which explained why baicalin could widely be used in the clinical treatment of stroke.

Comparative study of the effect of baicalin and its natural analogs on neurons with oxygen and glucose deprivation involving innate immune reaction of TLR2/TNFα.

This work is to study the baicalin and its three analogs, baicalin, wogonoside, and wogonin, on the protective effect of neuron from oxygen-glucose deprivation (OGD) and toll-like receptor 2 (TLR2) expression in OGD damage. The results showed that baicalin and its three analogs did protect neurons from OGD damage and downregulated protein level of TLR2. D-Glucopyranosiduronic acid on site 7 in the structure played a core of cytotoxicity of these flavonoid analogs. The methoxyl group on carbon 8 of the structure had the relation with TLR2 protein expression, as well as the anti-inflammation. In addition, we detected caspase3 and antioxidation capability, to investigate the effect of four analogs on cell apoptosis and total antioxidation competence in OGD model.

PI3K p55γ promoter activity enhancement is involved in the anti-apoptotic effect of berberine against cerebral ischemia-reperfusion.

Berberine is a candidate clinical neuroprotective agent against ischemic stroke. In the present study, we examined the influence of the PI3K/Akt pathway in mediating the anti-apoptotic effects of berberine. Oxygen-glucose deprivation and reoxygenation of nerve growth factor-differentiated PC12 cells and primary neurons, and bilateral common carotid artery occlusion in mice were used as in vitro and in vivo ischemia models. We found that the anti-apoptotic effects of berberine against ischemia were indeed mediated by the increased phosphor-activation of Akt (higher p-Akt to total Akt), leading to the intensified phosphorylation of Bad and the decreased cleavage of the pro-apoptotic protease caspase-3. Berberine action is specific for PI3K, rather than the upstream receptor tyrosine kinase. The anti-apoptotic effect is maintained in the presence of tyrosine kinase inhibitor genistein and the epidermal growth factor receptor inhibitor PD153035, but is suppressed by the PI3K inhibitor Ly294002 and the Akt inhibitor Akti-1/2.The unique PI3K regulatory subunit p55γ was upregulated by berberine during ischemia-reperfusion and was not blocked by these inhibitors. We constructed a reporter plasmid to detect PI3K p55γ promoter activity and found that berberine enhanced PI3K p55γ promoter activity during cerebral ischemia-reperfusion.

[Evaluation of allergen during processes of Fufang Kushen injection by IgG-promoter-HepG2 cell assay in vitro].

OBJECTIVE: To study the allergen in key processes during the production of Fufang Kushen injection by IgG promoter-HepG2 cells in vitro. METHOD: By transfecting a IgG promoter-regulating the expression of green fluorescent protein(GFP) plasmid into HepG2 cells, this transferred cells were incubated with common allergens (like puerarin, ovalbumin, LPS or Sal typhoid vi polysaccharide vaccine), excipients using in Fufang Kushen injection (NaOH, acetic acid, Tween-80 and ethanol) and samples from the key production processes of the injection for 30 minutes . Fluorescent photographs were analyzed the fluorescence intensity of the cells by using an image analysis software. RESULT: All of common allergens significantly increased the IgG expression. Two of the excipicents, acetic acids and Tween-80 were shown to increased the IgG expression, while others had no effect on IgG expression. In the 8 samples from the key processes in the production of Fufang Kushen injection, two of them stimulated IgG expression. CONCLUSION: IgG promoter-HepG2 cells are highly sensitive and specific to allergens, and thus can be applied to rapid screening of allergens in components and injections in transcriptional level. It is possible to use the IgG-promoter HepG2 cells in a real-time monitoring of allergens in the production processes of Chinese medicine injections.

[Investigation of inflammasome during excitation of IgG-HepG2 cells for evaluation of allergenic ingredients].

OBJECTIVE: To investigate the alteration of inflammasome and receptor during IgG promoter transfected to HepG2 cells. METHOD: By assay of Elisa to evaluate the secretion of IL-1 beta, IL-8, TNF-alpha and MCP-1 after puerarine and LPS administration, and by assay of real time PCR to evaluate the expression of mRNA of IL-1 beta, IL-8,TNF-alpha and MCP-1, as well as the receptors of TLR2, 4 and NOD2, MyD88. RESULT: IgG promoter did not active innate immunity and enhance the expression and secretion of inflammasome in HepG2. Puerarine did not active the inflammasome either. LPS activated the innate immunity and increased the secretion of IL-8, TNF-alpha and MCP-1. CONCLUSION: IgG-HepG2 cells could be used specifically as the model of allergy type II for ingredients screening. It is suggested that puerarine was suite for the activator for this type of allergy as positive control.

Comprehensive study of baicalin down-regulating NOD2 receptor expression of neurons with oxygen-glucose deprivation in vitro and cerebral ischemia-reperfusion in vivo.

Cerebral ischemia-reperfusion can activate several transcription factors and lead to inflammatory reactions, which related to pattern recognition receptors with immune activating functions. NOD2 (nucleotide-binding oligomerization domain protein 2) is one of the receptors involved in innate immune response and is genetically associated with several inflammatory reactions. Since baicalin has the pharmacological effects of anti-inflammation and protection of brain from cerebral ischemia-reperfusion, we studied baicalin's effect on NOD2/TNFα in the cell of oxygen-glucose deprivation (OGD) in vitro and the mice of cerebral ischemia-reperfusion in vivo. The results showed that NOD2 and TNFα were up regulated in the cells with oxygen-glucose deprivation, not only in BV2 cells, but also in both of PC12 cells and primary neuron cells, which suggested NOD2 could express directly in neuron while OGD treatment. Baicalin (10 µg/ml) could effectively down regulate the expression of NOD2 and TNFα in both mRNA and protein levels. Meanwhile, baicalin (50 mg/kg, i.p.) could also down regulate the expression of NOD2 and TNFα in protein levels significantly, in which agreed with its effect in vitro study. These data demonstrated that targeting on NOD2 especially in neurons directly was possibly attributed to the neural-protective effect of baicalin in the injury of cerebral ischemia-reperfusion.