Engineering extracellular vesicles with macrophage membrane fusion for ameliorating imiquimod-induced psoriatic skin inflammation.

INTRODUCTION: Herein, we developed an engineered extracellular vehicle (EV)-based method for ameliorating inflammatory responses in psoriasis. METHODS: EVs, derived from annexin A1 (ANXA1) overexpressing T cells, were co-extruded with M2 macrophage membrane to obtain engineered EVs. In vitro, the effect of engineered EVs on macrophage polarization was evaluated by real-time PCR. In imiquimod (IMQ)-induced psoriasis-like mouse model, the efficacy of engineered EVs in ameliorating psoriatic inflammation was evaluated by Psoriasis Area and Severity Index (PASI) score and immunohistochemistry staining after subcutaneous injection of EVs. RESULTS: The engineered EVs not only preserved the high stability of M2 macrophage membrane but also retained the macrophage reprogramming potential of ANXA1 overexpressed in T cells. In the psoriasis-like mouse model, subcutaneous injection of engineered EVs successfully reduced the PASI score and the levels of pro-inflammatory cytokines, including IL-1ß, IL-6, and TNF-α. Along with high biosafety, the administration of EVs also rescued the histomorphological changes of spleen, liver, and kidney. CONCLUSIONS: The engineered EVs exhibited the potential to alleviate inflammation of psoriasis, providing new insights and potential strategies for the immunotherapies of psoriasis.

Anti-cyclooxygenase, anti-glycation, and anti-skin aging effect of Dendrobium officinale flowers' aqueous extract and its phytochemical validation in aging.

Introduction: Dendrobium officinale Kimura et Migo (D. officinale) , widely called as "life-saving immortal grass" by Chinese folk, is a scarce and endangered species. The edible stems of D. officinale have been extensively studied for active chemical components and various bioactivities. However, few studies have reported the well-being beneficial effects of D. officinale flowers (DOF). Therefore, the present study aimed to investigate the in vitro biological potency of its aqueous extract and screen its active components. Methods: Antioxidant tests, including 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), the ferric reducing ability of plasma (FRAP), and intracellular reactive oxygen species (ROS) level analyses in primary human epidermal keratinocytes, anti-cyclooxygenase2 (COX-2) assay, anti-glycation assay (both fluorescent AGEs formation in a BSA fructose/glucose system and glycation cell assay), and anti-aging assay (quantification of collagen types I and III, and SA-ß-gal staining assay) were conducted to determine the potential biological effects of DOF extracts and its major compounds. Ultra-performance liquid chromatography-electrospray ionisation-quadrupole-time-of-flight-mass spectrometry (UPLC-ESI-QTOF-MS/MS) was performed to investigate the composition of DOF extracts. Online antioxidant post-column bioassay tests were applied to rapidly screen major antioxidants in DOF extracts. Results and discussion: The aqueous extract of D. officinale flowers was found to have potential antioxidant capacity, anti-cyclooxygenase2 (COX-2) effect, anti-glycation potency, and anti-aging effects. A total of 34 compounds were identified using UPLC-ESI-QTOF-MS/MS. Online ABTS radical analysis demonstrated that 1-O-caffeoyl-ß-D-glucoside, vicenin-2, luteolin-6-C-ß-D-xyloside-8-C-ß--D-glucoside, quercetin-3-O-sophoroside, rutin, isoquercitrin, and quercetin 3-O-(6″-O-malonyl)-ß-D-glucoside are the major potential antioxidants. In addition, all selected 16 compounds exerted significant ABTS radical scavenging ability and effective AGE suppressive activities. However, only certain compounds, such as rutin and isoquercitrin, displayed selective and significant antioxidant abilities, as shown by DPPH and FRAP, as well as potent COX-2 inhibitory capacity, whereas the remaining compounds displayed relatively weak or no effects. This indicates that specific components contributed to different functionalities. Our findings justified that DOF and its active compound targeted related enzymes and highlighted their potential application in anti-aging.

Neobavaisoflavone inhibits allergic inflammatory responses by suppressing mast cell activation.

Neobavaisoflavone (NBIF), a monomolecular compound extracted from Psoralea corylifolia (Leguminosae), is commonly used in traditional Chinese medicine for multiple purposes. NBIF is known to exert anti-fungal and anti-tumor effects, and promote bone formation. Whether NBIF exhibits anti-allergic effects by regulating mast cell activation remains unclear. Therefore, we designed this study to investigate the anti-allergic effects of NBIF on IgE/Ag-induced mouse bone marrow-derived mast cells and ovalbumin-induced asthma, and the passive systemic anaphylaxis (PSA) reaction in mice. Our results showed that NBIF suppresses the production of leukotriene C4, prostaglandin D2 and inflammatory cytokines, and decreases the degranulation of BMMCs stimulated by IgE/Ag. A thorough investigation ascertained that NBIF suppresses the phosphorylation of mitogen-activated protein kinases, and represses the nuclear factor-κB-related signaling pathway. In addition, the oral administration of NBIF in mice inhibited the IgE-induced PSA reaction in a dose-dependent manner. Overall, we provide new insights into how NBIF regulates the IgE/Ag-mediated signaling pathways. Moreover, our investigation promotes the potential use of NBIF in treating allergy and asthma.

Homoisoflavonoids Are Potent Glucose Transporter 2 (GLUT2) Inhibitors: A Potential Mechanism for the Glucose-Lowering Properties of Polygonatum odoratum.

Foods of high carbohydrate content such as sucrose or starch increase postprandial blood glucose concentrations. The glucose absorption system in the intestine comprises two components: sodium-dependent glucose transporter-1 (SGLT1) and glucose transporter 2 (GLUT2). Here five sappanin-type (SAP) homoisoflavonoids were identified as novel potent GLUT2 inhibitors, with three of them isolated from the fibrous roots of Polygonatum odoratum (Mill.) Druce. SAP homoisolflavonoids had a stronger inhibitory effect on 25 mM glucose transport (41.6 ± 2.5, 50.5 ± 7.6, 47.5 ± 1.9, 42.6 ± 2.4, and 45.7 ± 4.1% for EA-1, EA-2, EA-3, MOA, and MOB) than flavonoids (19.3 ± 2.2, 11.5 ± 3.7, 16.4 ± 2.4, 5.3 ± 1.0, 3.7 ± 2.2, and 18.1 ± 2.4% for apigenin, luteolin, quercetin, naringenin, hesperetin, and genistein) and phloretin (28.1 ± 1.6%) at 15 µM. SAP homoisoflavonoids and SGLT1 inhibitors were found to synergistically inhibit the uptake of glucose using an in vitro model comprising Caco-2 cells. This observed new mechanism of the glucose-lowering action of P. odoratum suggests that SAP homoisoflavonoids and their combination with flavonoid monoglucosides show promise as naturally functional ingredients for inclusion in foods and drinks designed to control postprandial glucose levels.

2',4'-Dihydroxy-6'-methoxy-3',5'-dimethylchalcone promoted glucose uptake and imposed a paradoxical effect on adipocyte differentiation in 3T3-L1 cells.

2',4'-Dihydroxy-6'-methoxy-3',5'-dimethylchalcone (DMC), one of the flavonoids isolated and purified from the dried flower buds of Cleistocalyx operculatus, was explored for its function in glucose uptake/glycogen synthesis in insulin-sensitive tissue cells and its effect and mechanism on 3T3-L1 preadipocyte differentiation. DMC (10 µM) treatment remarkably promoted glucose uptake in differentiated 3T3-L1 adipocytes (P < 0.05 vs control group), whereas the glucose uptake in L6 myoblasts and glycogen synthesis in HepG2 hepatocytes were not affected by the treatment. DMC had paradoxical effects on lipid accumulation in 3T3-L1 cells compared with differentiation control. High concentrations of DMC (10 and 20 µM) markedly diminished lipid accumulation; however, a low concentration of DMC (2.5 µM) enhanced lipid storage in 3T3-L1 cells (P < 0.01 vs differentiation control group), and 5 µM DMC did not impose a significant effect. It was demonstrated that the effect of DMC in lipid accumulation was controlled by the expression of PPAR-γ.

2',4'-Dihydroxy-6'-methoxy-3',5'-dimethylchalcone protects the impaired insulin secretion induced by glucotoxicity in pancreatic ß-cells.

2',4'-Dihydroxy-6'-methoxy-3',5'-dimethylchalcone (DMC), which is isolated and purified from the dried flower buds of Cleistocalyx operculatus (Roxb.) Merr. et Perry (Myrtaceae), was investigated for its insulinotropic benefits against glucotoxicity using in vitro methods. When exposed to high glucose at the cytotoxicity level for 48 h, RIN-5F ß-cells experienced a significant viability loss and impaired insulin secretion function, whereas cotreating with DMC could protect ß-cells against glucotoxicity-induced decrease in glucose-stimulated insulin secretion in a dose-dependent manner without affecting basal insulin secretion. It was demonstrated that DMC increased insulin secretion against glucotoxicity by simulating the effect of GLP-1 and enhancing the expression of GLP-1R, followed by activating the signal pathway of PDX-1, PRE-INS, and GLUT2-GCK. Another mechanism was that DMC avoided the pancreatic islet dysfunction resulting from cellular damage by suppressing the production of nitric oxide (NO) by iNOS, and the expression of MCP-1. The results indicated the potential application of DMC in the intervention against glucotoxicity-induced hyperglycemia.

Re-expression of IGF-II is important for beta cell regeneration in adult mice.

BACKGROUND: The key factors which support re-expansion of beta cell numbers after injury are largely unknown. Insulin-like growth factor II (IGF-II) plays a critical role in supporting cell division and differentiation during ontogeny but its role in the adult is not known. In this study we investigated the effect of IGF-II on beta cell regeneration. METHODOLOGY/PRINCIPAL FINDINGS: We employed an in vivo model of 'switchable' c-Myc-induced beta cell ablation, pIns-c-MycER(TAM), in which 90% of beta cells are lost following 11 days of c-Myc (Myc) activation in vivo. Importantly, such ablation is normally followed by beta cell regeneration once Myc is deactivated, enabling functional studies of beta cell regeneration in vivo. IGF-II was shown to be re-expressed in the adult pancreas of pIns-c-MycER(TAM)/IGF-II(+/+) (MIG) mice, following beta cell injury. As expected in the presence of IGF-II beta cell mass and numbers recover rapidly after ablation. In contrast, in pIns-c-MycER(TAM)/IGF-II(+/-) (MIGKO) mice, which express no IGF-II, recovery of beta cell mass and numbers were delayed and impaired. Despite failure of beta cell number increase, MIGKO mice recovered from hyperglycaemia, although this was delayed. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that beta cell regeneration in adult mice depends on re-expression of IGF-II, and supports the utility of using such ablation-recovery models for identifying other potential factors critical for underpinning successful beta cell regeneration in vivo. The potential therapeutic benefits of manipulating the IGF-II signaling systems merit further exploration.

c-Myc directly induces both impaired insulin secretion and loss of ß-cell mass, independently of hyperglycemia in vivo.

c-Myc (Myc) is a mediator of glucotoxicity but could also independently compromise ß-cell survival and function. We have shown that after Myc activation in adult ß-cells in vivo, apoptosis is preceded by hyperglycemia, suggesting glucotoxicity might contribute to Myc-induced apoptosis. To address this question conditional Myc was activated in ß-cells of adult pIns-c-MycER(TAM) mice in vivo in the presence or absence of various glucose-lowering treatments, including exogenous insulin and prior to transplantation with wild-type islets. Changes in blood glucose levels were subsequently correlated with changes in ß-cell mass and markers of function/differentiation. Activation of c-Myc resulted in reduced insulin secretion, hyperglycemia and loss of ß-cell differentiation, followed by reduction in mass. Glucose-lowering interventions did not prevent loss of ß-cells. Therefore, Myc can cause diabetes by direct effects on ß-cell apoptosis even in the absence of potentially confounding secondary hyperglycemia. Moreover, as loss of ß-cell differentiation/function and hyperglycemia are not prevented by preventing ß-cell apoptosis, we conclude that Myc might contribute to the pathogenesis of diabetes by directly coupling cell cycle entry and ß-cell failure through two distinct pathways.

Integrating semantic annotation and information visualization for the analysis of multichannel fluorescence micrographs from pancreatic tissue.

The challenging problem of computational bioimage analysis receives growing attention from life sciences. Fluorescence microscopy is capable of simultaneously visualizing multiple molecules by staining with different fluorescent dyes. In the analysis of the result multichannel images, segmentation of ROIs resembles only a first step which must be followed by a second step towards the analysis of the ROI's signals in the different channels. In this paper we present a system that combines image segmentation and information visualization principles for an integrated analysis of fluorescence micrographs of tissue samples. The analysis aims at the detection and annotation of cells of the Islets of Langerhans and the whole pancreas, which is of great importance in diabetes studies and in the search for new anti-diabetes treatments. The system operates with two modules. The automatic annotation module applies supervised machine learning for cell detection and segmentation. The second information visualization module can be used for an interactive classification and visualization of cell types following the link-and-brush principle for filtering. We can compare the results obtained with our system with results obtained manually by an expert, who evaluated a set of example images three times to account for his intra-observer variance. The comparison shows that using our system the images can be evaluated with high accuracy which allows a considerable speed up of the time-consuming evaluation process.