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-MycERTAM, 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-MycERTAM/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-MycERTAM/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

Homoisoflavonoids are potent glucose transporter 2 (GLUT 2) 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

Functional study of beta cell mass regulation in vivo

Those key factors, supporting re-expansion of beta cell numbers after injury in various model systems, are largely unknown. Insulin-like growth factor II (IGF-II), an important member from the IGF family, 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 in beta cell regeneration. An in vivo model of „switchable‟ c-Myc-induced beta cell ablation, pIns-c-MycERTAM (Pelengaris, Khan et al. 2002), which exhibits beta cell regeneration once Myc is deactivated, is employed in this study of the IGF-II function. Here we show for the first time that IGF-II is re-expressed in the adult pancreas following beta cell injury. Moreover, whereas a 90% beta cell ablation was induced in both pIns-cMycERTAM/IGF-II WT (MIG) and pIns-cMycERTAM/IGF-II KO (MIGKO) mice, a recovery up to 3 months was performed. By investigating the beta cell mass and numbers our results demonstrate that re-expression of IGF-II is important in supporting the beta cell regeneration in adult mice. Moreover this study supports the utility of using such ablation-recovery models for identifying other potential factors critical for underpinning successful beta cell regeneration in vivo. Both Myc and PML contribute to the regulation of apoptosis. Recent studies suggest that Myc and PML may interact at several levels in control of cell fate. Here we examined whether loss of the PML protein, which has been shown to regulate apoptosis via the p53 pathway, can prevent or affect c-Myc-induced beta cell apoptosis in pIns-c-MycERTAM transgenic mice. Together with the Applied Neuroinformatics Group at the University of Bielefeld in Germany, we have been developing and validating a machine learning based system to analyze beta and alpha cell numbers (Herold, Zhou et al. 2009). Comparative results between traditional techniques and this new method are presented here.EThOS - Electronic Theses Online ServiceUniversity of WarwickGBUnited Kingdo

Functional study of beta cell mass regulation in vivo

Those key factors, supporting re-expansion of beta cell numbers after injury in various model systems, are largely unknown. Insulin-like growth factor II (IGF-II), an important member from the IGF family, 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 in beta cell regeneration. An in vivo model of „switchable‟ c-Myc-induced beta cell ablation, pIns-c-MycERTAM (Pelengaris, Khan et al. 2002), which exhibits beta cell regeneration once Myc is deactivated, is employed in this study of the IGF-II function. Here we show for the first time that IGF-II is re-expressed in the adult pancreas following beta cell injury. Moreover, whereas a 90% beta cell ablation was induced in both pIns-cMycERTAM/IGF-II WT (MIG) and pIns-cMycERTAM/IGF-II KO (MIGKO) mice, a recovery up to 3 months was performed. By investigating the beta cell mass and numbers our results demonstrate that re-expression of IGF-II is important in supporting the beta cell regeneration in adult mice. Moreover this study supports the utility of using such ablation-recovery models for identifying other potential factors critical for underpinning successful beta cell regeneration in vivo. Both Myc and PML contribute to the regulation of apoptosis. Recent studies suggest that Myc and PML may interact at several levels in control of cell fate. Here we examined whether loss of the PML protein, which has been shown to regulate apoptosis via the p53 pathway, can prevent or affect c-Myc-induced beta cell apoptosis in pIns-c-MycERTAM transgenic mice. Together with the Applied Neuroinformatics Group at the University of Bielefeld in Germany, we have been developing and validating a machine learning based system to analyze beta and alpha cell numbers (Herold, Zhou et al. 2009). Comparative results between traditional techniques and this new method are presented here

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

IntroductionDendrobium 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.MethodsAntioxidant 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-β-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 discussionThe 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-β-D-glucoside, vicenin-2, luteolin-6-C-β-D-xyloside-8-C-β--D-glucoside, quercetin-3-O-sophoroside, rutin, isoquercitrin, and quercetin 3-O-(6″-O-malonyl)-β-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

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

c-Myc (Myc) is a mediator of glucotoxicity but could also independently compromise beta-cell survival and function. We have shown that after Myc activation in adult beta-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 beta-cells of adult plns-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 beta-cell mass and markers of function/differentiation. Activation of c-Myc resulted in reduced insulin secretion, hyperglycemia and loss of beta-cell differentiation, followed by reduction in mass. Glucose-lowering interventions did not prevent loss of beta-cells. Therefore, Myc can cause diabetes by direct effects on beta-cell apoptosis even in the absence of potentially confounding secondary hyperglycemia. Moreover, as loss of beta-cell differentiation/function and hyperglycemia are not prevented by preventing beta-cell apoptosis, we conclude that Myc might contribute to the pathogenesis of diabetes by directly coupling cell cycle entry and beta-cell failure through two distinct pathways

A way toward analyzing high-content bioimage data by means of semantic annotation and visual data mining

In the last years, bioimaging has turned from qualitative measurements towards a high-throughput and highcontent modality, providing multiple variables for each biological sample analyzed. We present a system which combines machine learning based semantic image annotation and visual data mining to analyze such new multivariate bioimage data. Machine learning is employed for automatic semantic annotation of regions of interest. The annotation is the prerequisite for a biological object-oriented exploration of the feature space derived from the image variables. With the aid of visual data mining, the obtained data can be explored simultaneously in the image as well as in the feature domain. Especially when little is known of the underlying data, for example in the case of exploring the effects of a drug treatment, visual data mining can greatly aid the process of data evaluation. We demonstrate how our system is used for image evaluation to obtain information relevant to diabetes study and screening of new anti-diabetes treatments. Cells of the Islet of Langerhans and whole pancreas in pancreas tissue samples are annotated and object specific molecular features are extracted from aligned multichannel fluorescence images. These are interactively evaluated for cell type classification in order to determine the cell number and mass. Only few parameters need to be specified which makes it usable also for non computer experts and allows for high-throughput analysis

A machine learning based system for multichannel fluorescence analysis in pancreatic tissue bioimages

Fluorescence microscopy has regained much attention in the last years especially in the field of systems biology. It has been recognized as a rich source of information extending the existing sources since it allows simultaneous collection of spatial and temporal protein information. In order to enable a high-throughput and high-content image analysis, sophisticated image processing routines become essential. We present a machine learning based approach for semantic image annotation i.e. identifying biologically meaningful objects. A semantic annotation becomes necessary, if image variables have to be associated to single biological objects, for example cells. We apply our method to pancreatic tissue sample images to detect and annotate cells of the Islets of Langerhans and whole pancreas. Based on the annotation, aligned multichannel fluorescence images are evaluated for cell type classification allowing accurate and rapid determination of the cell number and mass. This high-throughput analytical technique, requiring only few parameters, should he of great value in diabetes studies and for screening of new anti-diabetes treatments

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. (C) 2009 Elsevier Ltd. All rights reserved

Abnormal functional connectivity of the striatum in first‐episode drug‐naive early‐onset Schizophrenia

Abstract Abnormal brain network connectivity is strongly implicated in the pathogenesis of schizophrenia. The striatum, consisting of the caudate and putamen, is the major treatment target for antipsychotics, the primary treatments for schizophrenia; however, there are few studies on the functional connectivity (FC) of striatum in drug‐naive early‐onset schizophrenia (EOS) patients. We examined the FC values of the caudate nucleus and putamen with whole brain by resting‐state functional magnetic resonance imaging (RS‐fMRI) and the associations with indices of clinical severity. Patients demonstrated abnormal FC between subregions of the putamen and both the visual network (left middle occipital gyrus) and default mode network (bilateral anterior cingulate, left superior frontal, and right middle frontal gyri). Furthermore, FC between dorsorostral putamen and left superior frontal gyrus correlated with both positive symptom subscore and total score on the Positive and Negative Syndrome Scale (PANSS). These findings demonstrate abnormal FC between the striatum and other brain areas even in the early stages of schizophrenia, supporting neurodevelopmental disruption in disease etiology and expression