Increased FAT/CD36 Cycling and Lipid Accumulation in Myotubes Derived from Obese Type 2 Diabetic Patients

BACKGROUND: Permanent fatty acid translocase (FAT/)CD36 relocation has previously been shown to be related to abnormal lipid accumulation in the skeletal muscle of type 2 diabetic patients, however mechanisms responsible for the regulation of FAT/CD36 expression and localization are not well characterized in human skeletal muscle. METHODOLOGY/PRINCIPAL FINDINGS: Primary muscle cells derived from obese type 2 diabetic patients (OBT2D) and from healthy subjects (Control) were used to examine the regulation of FAT/CD36. We showed that compared to Control myotubes, FAT/CD36 was continuously cycling between intracellular compartments and the cell surface in OBT2D myotubes, independently of lipid raft association, leading to increased cell surface FAT/CD36 localization and lipid accumulation. Moreover, we showed that FAT/CD36 cycling and lipid accumulation were specific to myotubes and were not observed in reserve cells. However, in Control myotubes, the induction of FAT/CD36 membrane translocation by the activation of (AMP)-activated protein kinase (AMPK) pathway did not increase lipid accumulation. This result can be explained by the fact that pharmacological activation of AMPK leads to increased mitochondrial beta-oxidation in Control cells. CONCLUSION/SIGNIFICANCE: Lipid accumulation in myotubes derived from obese type 2 diabetic patients arises from abnormal FAT/CD36 cycling while lipid accumulation in Control cells results from an equilibrium between lipid uptake and oxidation. As such, inhibiting FAT/CD36 cycling in the skeletal muscle of obese type 2 diabetic patients should be sufficient to diminish lipid accumulation

An algorithm for distinguishing efficiently bit-strings by their subsequences

AbstractA linear on-line algorithm for computing a shortest subsequence that distinguishes two different bit-strings is presented. The method is based on a special way of factorizing strings

Miniature laser powder bed fusion system for in situ synchrotron x-ray micro-computed tomography experiments at the European Synchrotron Radiation Facility

We describe our miniature laser powder bed fusion (L-PBF) system for in situ synchrotron x-ray micro-computed tomography (XCT) at the European Synchrotron Radiation Facility. This replicator was designed to extend the characterization of L-PBF to 3D. This instrument fills in a technical gap because the existing replicators were mostly designed to shed light on the dynamic mechanisms involved in molten pool formation but, therefore, suffered from a lack of 3D information. Technical details regarding the setup and beamline integration are given. Experimental validations via post-mortem XCT scans and in situ scans acquired during experiments conducted at the BM05 beamline of the European Synchrotron Radiation Facility are provided. Based on a few illustrative examples, we show that such a replicator opens the path to collect key 3D information that to date could not be available. Our miniature instrument complements the other replicators developed in the world by other research groups that enable operando x-ray imaging (radiography) and operando x-ray diffraction

First evidence of “in situ” Eemian sediments on the high plateau of Evian (Western Alps, France) : implications for the chronology of the Last Glaciation

International audienceA 2 m profile of organic sediments, interbedded between two tills, was taken from the Evian high plateau at Hameau de Maravant, 860 m a.s.l. (Haute-Savoie, Western Alps, France). Pollen, plant macrofossils and insect remains were used to reconstruct the local palaeoenvironment, which consisted of a moss and Carex mire, surrounded by a dense Abies and Picea mixed forest. Pollen and macrofossil data indicate that this peat layer was deposited at the end of the Eemian interglacial. The lower till should therefore be assigned to the penultimate glaciation and the upper till to the maximum extent of the Rhône glacier during the Würm. A comparison of the results with previous studies carried out in the Geneva area and other alpine valleys has yielded a detailed reconstruction of the past fluctuations of the Rhône glacier: 1. a first Early/Lower Würmian advance, reaching the region around Lyon; 2. a subsequent retreat of ice; 3. a second moderate readvance, restricted to the surroundings of Geneva, followed by a final deglaciation. A continuous lacustrine sequence has been obtained from the nearby Roseire peat-bog (890 m a.s.l). Pollen and radiometric results show the establishment of a former palaeolake during the Upper Pleniglacial, probably before ca. 22 450±850 cal years BP, thus implying that the high plateau was ice-free from that time. These new data appear to suggest that the maximal extension of the Rhône glacier occurred prior to the Last Glacial Maximum (OIS 2) and, according to a well-documented geomorphological context, probably during the Lower Würmian Pleniglacial