Acute mTOR inhibition induces insulin resistance and alters substrate utilization in vivo.

The effect of acute inhibition of both mTORC1 and mTORC2 on metabolism is unknown. A single injection of the mTOR kinase inhibitor, AZD8055, induced a transient, yet marked increase in fat oxidation and insulin resistance in mice, whereas the mTORC1 inhibitor rapamycin had no effect. AZD8055, but not rapamycin reduced insulin-stimulated glucose uptake into incubated muscles, despite normal GLUT4 translocation in muscle cells. AZD8055 inhibited glycolysis in MEF cells. Abrogation of mTORC2 activity by SIN1 deletion impaired glycolysis and AZD8055 had no effect in SIN1 KO MEFs. Re-expression of wildtype SIN1 rescued glycolysis. Glucose intolerance following AZD8055 administration was absent in mice lacking the mTORC2 subunit Rictor in muscle, and in vivo glucose uptake into Rictor-deficient muscle was reduced despite normal Akt activity. Taken together, acute mTOR inhibition is detrimental to glucose homeostasis in part by blocking muscle mTORC2, indicating its importance in muscle metabolism in vivo

Lead-DBS v3.0: Mapping Deep Brain Stimulation Effects to Local Anatomy and Global Networks.

Following its introduction in 2014 and with support of a broad international community, the open-source toolbox Lead-DBS has evolved into a comprehensive neuroimaging platform dedicated to localizing, reconstructing, and visualizing electrodes implanted in the human brain, in the context of deep brain stimulation (DBS) and epilepsy monitoring. Expanding clinical indications for DBS, increasing availability of related research tools, and a growing community of clinician-scientist researchers, however, have led to an ongoing need to maintain, update, and standardize the codebase of Lead-DBS. Major development efforts of the platform in recent years have now yielded an end-to-end solution for DBS-based neuroimaging analysis allowing comprehensive image preprocessing, lead localization, stimulation volume modeling, and statistical analysis within a single tool. The aim of the present manuscript is to introduce fundamental additions to the Lead-DBS pipeline including a deformation warpfield editor and novel algorithms for electrode localization. Furthermore, we introduce a total of three comprehensive tools to map DBS effects to local, tract- and brain network-levels. These updates are demonstrated using a single patient example (for subject-level analysis), as well as a retrospective cohort of 51 Parkinson's disease patients who underwent DBS of the subthalamic nucleus (for group-level analysis). Their applicability is further demonstrated by comparing the various methodological choices and the amount of explained variance in clinical outcomes across analysis streams. Finally, based on an increasing need to standardize folder and file naming specifications across research groups in neuroscience, we introduce the brain imaging data structure (BIDS) derivative standard for Lead-DBS. Thus, this multi-institutional collaborative effort represents an important stage in the evolution of a comprehensive, open-source pipeline for DBS imaging and connectomics

Enhanced Fatty Acid Oxidation and FATP4 Protein Expression after Endurance Exercise Training in Human Skeletal Muscle

FATP1 and FATP4 appear to be important for the cellular uptake and handling of long chain fatty acids (LCFA). These findings were obtained from loss- or gain of function models. However, reports on FATP1 and FATP4 in human skeletal muscle are limited. Aerobic training enhances lipid oxidation; however, it is not known whether this involves up-regulation of FATP1 and FATP4 protein. Therefore, the aim of this project was to investigate FATP1 and FATP4 protein expression in the vastus lateralis muscle from healthy human individuals and to what extent FATP1 and FATP4 protein expression were affected by an increased fuel demand induced by exercise training. Eight young healthy males were recruited to the study. All subjects were non smokers and did not participate in regular physical activity (<1 time per week for the past 6 months, VO2peak 3.4±0.1 l O2 min−1). Subjects underwent an 8 week supervised aerobic training program. Training induced an increase in VO2peak from 3.4±0.1 to 3.9±0.1 l min−1 and citrate synthase activity was increased from 53.7±2.5 to 80.8±3.7 µmol g−1 min−1. The protein content of FATP4 was increased by 33%, whereas FATP1 protein content was reduced by 20%. Interestingly, at the end of the training intervention a significant association (r2 = 0.74) between the observed increase in skeletal muscle FATP4 protein expression and lipid oxidation during a 120 min endurance exercise test was observed. In conclusion, based on the present findings it is suggested that FATP1 and FATP4 proteins perform different functional roles in handling LCFA in skeletal muscle with FATP4 apparently more important as a lipid transport protein directing lipids for lipid oxidation

Subject characteristics.

<p>Data are means ± SE.</p><p>*p<0.05;</p><p>**p<0.01 compared with Pre Training, <i>n = 8</i>.</p

Divergent effects of exercise training on membrane bound lipid binding protein expression in human skeletal muscle.

<p>Protein concentration of total crude membrane (TCM) fractions before and after 8 weeks of exercise training were determined and equal protein amounts were resolved by SDS-PAGE and membranes were immunoblotted using antibodies specific for FATP1, FATP4, FAT/CD36 and FABPpm. β-actin was run on membranes as control and was unchanged with exercise training. Eight weeks of endurance exercise training resulted in reduced FATP1 protein expression in skeletal muscle (A). In contrast, (B) FATP4 and (C) FABPpm protein expression was increased after the training intervention compared to before training. FAT/CD36 protein expression was similar before and after training (D). Representative Western blots of protein levels before (Pre) and after the exercise training period (Post) from the same subjects are shown (E). Black bars represents pre training values and grey bars represents post training values. **; <i>p</i><0.01.</p

The Caveolae proteins Caveolin1 and Caveolin 3 were unaffected by exercise training.

<p>Eight weeks of endurance exercise training did not affect (A) Caveolin 1 and (B) Caveolin 3 protein levels. Protein concentration of TCM fractions pre- and post training were determined and equal protein amounts were resolved by SDS-PAGE and membranes were immunoblotted using antibodies specific for Caveolin 1 and Caveolin 3. β-actin was run on membranes as control and was unchanged with exercise training. Representative Western blots of protein levels before (Pre) and after the exercise training period (Post) from the same subjects are shown (C). Black bars represents pre training values and grey bars represents post training values.</p

Association between lipid oxidation and exercise training induced adaptations in FATP4 protein expression in human skeletal muscle.

<p>Eight weeks of endurance exercise training resulted in a shift in substrate choice towards a higher FA utilization during submaximal exercise. This training induced adaptation was associated with the observed increase in FATP4 protein expression.</p

No response of exercise training on soluble lipid binding protein expression in human skeletal muscle.

<p>Eight weeks of endurance exercise training did not affect (A) FABPc or (B) ACBP protein levels in human skeletal muscle. Protein concentration of cytosol fractions pre- and post training were determined and equal protein amounts were resolved by SDS-PAGE and membranes were immunoblotted using antibodies specific for FABPc and ACBP. β-tubulin was run on membranes as control and was unchanged with exercise training. Representative Western blots of protein levels before (Pre) and after the exercise training period (Post) from the same subjects are shown (C). Black bars represents pre training values and grey bars represents post training values.</p

Representative images of the proteins analyzed in total crude membranes (TCM) and soluble cytocolic fractions (Cytosol) from human vastus lateralis muscle are shown.

<p>Protein concentration of TCM and cytosol fractions pre- and post training were determined and equal protein amounts were resolved by SDS-PAGE and membranes were immunoblotted using antibodies specific for FATP1; fatty acid transport protein 1 (63 kDa) and FATP4; fatty acid transport protein 4 (72 kDa), FAT/CD36; fatty acid translocase CD36 (88 kDa), FABPpm; membrane bound fatty acid binding protein (43 kDa), FABPc; cytoplasmic fatty acid binding protein (14 kDa), ACBP; acyl-CoA binding protein (10 kDa), and Caveolin 1 (22 kDa), Caveolin 3 (18 kDa). All Western blots were run in parallel with molecular weight markers. Relevant molecular weight markings above and below each analyzed protein are indicated.</p