A5062971753- Pancreatic function and diabetes
- Ion channel regulation and function
- Cardiac Ischemia and Reperfusion
- Diabetes and associated disorders
- Genetics and Neurodevelopmental Disorders
- Cellular transport and secretion
- Genetic Syndromes and Imprinting
- Metabolism, Diabetes, and Cancer
- Diabetes Management and Research
- Lipid Membrane Structure and Behavior
- Plant biochemistry and biosynthesis
- Mass Spectrometry Techniques and Applications
- Fermentation and Sensory Analysis
- Receptor Mechanisms and Signaling
- Cardiac electrophysiology and arrhythmias
- Neurobiology and Insect Physiology Research
- Neonatal Health and Biochemistry
- Diet, Metabolism, and Disease
- Heme Oxygenase-1 and Carbon Monoxide
- Plant Gene Expression Analysis
- Drug Transport and Resistance Mechanisms
- Mechanical Circulatory Support Devices
- Pharmacology and Obesity Treatment
- Connexins and lens biology
- Endoplasmic Reticulum Stress and Disease
University of Pittsburgh
2009-2023
Ames National Laboratory
2006
Boston Children's Hospital
2004
University of Pennsylvania
1998-2000
Howard Hughes Medical Institute
1994
Stanford University
1994
Massachusetts Institute of Technology
1986-1993
University of Southern California
1983-1986
Carbon monoxide (CO), a byproduct of heme catabolism by oxygenase (HO), confers potent antiinflammatory effects. Here we demonstrate that CO derived from HO-1 inhibited Toll-like receptor (TLR) 2, 4, 5, and 9 signaling, but not TLR3-dependent in macrophages. Ligand-mediated trafficking to lipid rafts represents an early event signal initiation immune cells. Trafficking TLR4 response LPS was reactive oxygen species (ROS) dependent because it diphenylene iodonium, inhibitor NADPH oxidase,...
ATP-sensitive potassium (“K ATP ”) channels are rapidly inhibited by intracellular ATP. This inhibition plays a crucial role in the coupling of electrical activity to energy metabolism variety cells. The K channel is formed from four each sulfonylurea receptor (SUR) regulatory subunit and an inwardly rectifying (K ir 6.2) pore-forming subunit. We used systematic chimeric point mutagenesis, combined with patch-clamp recording, investigate molecular basis ATP-dependent gating mouse pancreatic...
A complex involving Derlin-1 and p97 mediates the retrotranslocation endoplasmic reticulum (ER)-associated degradation of misfolded proteins in yeast is used by certain viruses to promote host cell protein (Romisch, K. (2005) Annu. Rev. Cell Dev. Biol. 21, 435-456; Lilley, B. N., Ploegh, H. L. (2004) Nature 429, 834-840; Ye, Y., Shibata, Yun, C., Ron, D., Rapoport, T. A. 841-847). We asked whether components this pathway are involved reticulum-associated mammalian integral membrane protein,...
We have characterized the behavior and genetics of Drosophila mutant radish (rsh gene). Initial learning flies in two olfactory discrimination tests is high, but subsequent memory decays rapidly at both early late times after training. Anesthesia-resistant (consolidated memory) undetectable 3 hr The shows normal locomotor activity sensitivity to odor cues electric-shock reinforcement used tests. gene maps within a 180-kb interval 11D-E region X chromosome.
α-Synuclein has been studied in numerous cell types often associated with secretory processes. In pancreatic β-cells, α-synuclein might therefore play a similar role by interacting organelles involved insulin secretion. We tested for localizing to insulin-secretory granules and characterized its glucose-stimulated Immunohistochemistry fluorescent sulfonylureas were used test localization immunoprecipitation Western blot analysis interaction between K ATP channels, ELISA assays the effect of...
With ATP sites on Kir6.2 that inhibit activity and ADP SUR1 antagonize the inhibition, ATP-sensitive potassium channels (KATP channels) are designed as exquisite sensors of adenine nucleotide levels signal changes in glucose metabolism. If pancreatic KATP localize to insulin secretory granule, they would be well positioned transduce metabolism into granule transport exocytosis. Tests for localized granules led following observations: fluorescent sulfonylureas bind channel specifically label...
Glucokinase (GK) activity is essential for the physiological regulation of insulin secretion by glucose. Because enzyme exerts nearly total control over glucose metabolism in β-cell, even small changes GK exert effects on glucose-stimulated and, consequently, blood concentration. Using quantitative imaging multicolor fluorescent proteins fused to GK, we found that association with granules regulated β-cell. Glucose stimulation increased rate fluorescence recovery after photobleaching...
In healthy individuals, plasma insulin levels oscillate in both fasting and fed states. Numerous studies of isolated pancreata pancreatic islets support the hypothesis that oscillations arise because underlying rate secretion also oscillates; yet, has never been observed to individual beta-cells. Using expressed fluorescent vesicle cargo proteins total internal reflection fluorescence (TIRF) microscopy, we demonstrate glucose stimulates human beta-cells secrete vesicles short, coordinated...
In an effort to characterize the hepatocyte bile acid transport system, a photoreactive derivative of taurocholate, (7,7-azo-3a,12a-dihydroxy-5~-cholan-24-oyl)-2-aminoethanesulfonic (7-ADTC) has been synthesized and its properties compared those natural substrate.Both synthetic analog were shown be transported against electrochemical gradient as well chemical gradient.Transport function concentration presence sodium indicated that both substrates taken up by sodium-dependent...
We combined confocal and live‐cell imaging with a novel molecular strategy aimed at revealing mechanisms underlying glucose‐regulated insulin vesicle secretion. The ‘Ins‐C‐GFP’ reporter monitors secretory peptide targeting, trafficking, exocytosis without directly tagging the mature secreted peptide. trapped green fluorescent protein (GFP) in equimolar quantity within by fusing it C of proinsulin which only after nascent sealing acidification is cleaved from A B chains insulin. Ins‐C‐GFP...
Type 1 diabetes results from the selective destruction of insulin-producing β cells in islets Langerhans, and autoimmune T are thought to be mediators this destruction. also responsible for allorejection once transplanted into a patient reduce negative consequences lack insulin. To better understand these processes, we have developed transgenic mouse expressing proinsulin II tagged with live-cell fluorescent reporter protein, Timer. Timer protein is unique because it changes color green red...
Prader-Willi syndrome (PWS) is a multisystem disorder caused by genetic loss of function cluster imprinted, paternally expressed genes. Neonatal failure to thrive in PWS followed childhood-onset hyperphagia and obesity among other endocrine behavioral abnormalities. typically assumed be an unknown hypothalamic-pituitary dysfunction, but the underlying pathogenesis remains unknown. A transgenic deletion mouse model (TgPWS) has severe thrive, with very low levels plasma insulin glucagon fetal...
KCl depolarization is widely used to mimic the during glucose-stimulated insulin secretion. Consequently, secretion elicited by often regarded as equivalent of first phase glucose-induced Here, effects both stimuli were compared measuring perifused mouse islets, cytosolic Ca 2+ concentration single beta-cells and mobility submembrane granules TIRF microscopy primary beta-cells. Two cargo-directed granule labels namely insulin-EGFP C-peptide-emGFP. The behaviour common was compare effect...
The ATP-sensitive potassium (KATP) channel is named after its characteristic inhibition by intracellular ATP. a centerpiece of how the KATP sets electrical signaling to energy state cell. In β cell endocrine pancreas, for example, ATP results from high blood glucose levels and turns on activity leading insulin release. underlying gating mechanism (ATP gating) includes stabilization closed states, but action open disputed. original models proposed that directly binds state, whereas recent...
AbstractHyperglycemia can result from a relative or absolute lack of functional insulin secreted by the pancreatic β-cells. Prohormone processing enzymes play an essential role in secretion mature and fully insulin. Defects including prohormone convertases 1/3 2, carboxypeptidase E (CPE) lead to β-cell stress hyperproinsulinemia, both which are features type 2 diabetes. Despite their importance, regulation this family remain be elucidated. Previously, we demonstrated that lipotoxicity led...
Understanding mechanisms by which glibenclamide stimulates insulin release is important, particularly given recent promising treatment of permanent neonatal diabetic subjects. Antidiabetic sulfonylureas are thought to stimulate secretion solely inhibiting their high-affinity ATP-sensitive potassium (K(ATP)) channel receptors at the plasma membrane beta-cells. This normally occurs during glucose stimulation, where ATP inhibition plasmalemmal K(ATP) channels leads voltage activation L-type...
Abstract Background Excessive generation of reactive oxygen species (ROS) causing oxidative stress plays a major role in the pathogenesis diabetes by inducing beta cell secretory dysfunction and apoptosis. Recent evidence has shown that C‐peptide, produced cells co‐secreted with insulin circulation healthy individuals, decreases ROS prevents apoptosis dysfunctional vascular endothelial cells. In this study, we tested hypothesis an autocrine activity C‐peptide similarly when INS1 are exposed...