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Dysregulation of glucose homeostasis contributes to insulin resistance and type 2 diabetes. Whilst exercise stimulated activation of AMP-activated protein kinase (AMPK), an important energy sensor, has been highlighted for its potential to promote insulin-stimulated glucose uptake, the underlying mechanisms for this remain largely unknown. Here we found that AMPK positively regulates the activation of Rab5, a small GTPase which is involved in regulating Glut4 translocation, in both myoblasts and skeletal muscles. We further verified that TBC1D17, identified as a potential interacting partner of Rab5 in our recent study, is a novel GTPase activating protein (GAP) of Rab5. TBC1D17-Rab5 axis regulates transport of Glut1, Glut4, and transferrin receptor. TBC1D17 interacts with Rab5 or AMPK via its TBC domain or N-terminal 1-306 region (N-Ter), respectively. Moreover, AMPK phosphorylates the Ser 168 residue of TBC1D17 which matches the predicted AMPK consensus motif. N-Ter of TBC1D17 acts as an inhibitory region by directly interacting with the TBC domain. Ser168 phosphorylation promotes intra-molecular interaction and therefore enhances the auto-inhibition of TBC1D17. Our findings reveal that TBC1D17 acts as a molecular bridge that links AMPK and Rab5 and delineate a previously unappreciated mechanism by which the activation of TBC/RabGAP is regulated.

Rab5 is a master regulator for endosome biogenesis and transport while its in vivo physiological function remains elusive. Here, we find that Rab5a is upregulated in several in vivo and in vitro myogenesis models. By generating myogenic Rab5a-deficient mice, we uncover the essential roles of Rab5a in regulating skeletal muscle regeneration. We further reveal that Rab5a promotes myoblast differentiation and directly interacts with insulin receptor substrate 1 (IRS1), an essential scaffold protein for propagating IGF signaling. Rab5a interacts with IRS1 in a GTP-dependent manner and this interaction is enhanced upon IGF-1 activation and myogenic differentiation. We subsequently identify that the arginine 207 and 222 of IRS1 and tyrosine 82, 89, and 90 of Rab5a are the critical amino acid residues for mediating the association. Mechanistically, Rab5a modulates IRS1 activation by coordinating the association between IRS1 and the IGF receptor (IGFR) and regulating the intracellular membrane targeting of IRS1. Both myogenesis-induced and IGF-evoked AKT-mTOR signaling are dependent on Rab5a. Myogenic deletion of Rab5a also reduces the activation of AKT-mTOR signaling during skeletal muscle regeneration. Taken together, our study uncovers the physiological function of Rab5a in regulating muscle regeneration and delineates the novel role of Rab5a as a critical switch controlling AKT-mTOR signaling by activating IRS1.

Tendon repair is a clinical challenge because of the limited understanding on tenogenesis. The synthesis of type I collagen (Collagen I) and other extracellular matrix are essential for tendon differentiation and homeostasis. Current studies on tenogenesis focused mostly on the tenogenic transcriptional factors while the signaling controlling tenogenesis on translational level remains largely unknown. Here, we showed that mechanistic target of rapamycin (mTOR) signaling was activated by protenogenic growth factor, transforming growth factors beta1, and insulin-like growth factor-I. The expression of mTOR was upregulated during tenogenesis of mesenchymal stem cells (MSCs). Moreover, mTOR was downregulated in human tendinopathy tissues and was inactivated upon statin treatment. Both inhibition and depletion of AKT or mTOR significantly reduced type I collagen production and impaired tenogenesis of MSCs. Tendon specific-ablation of mTOR resulted in tendon defect and reduction of Collagen I. However, there is no evident downregulation of tendon associated collagens at the transcription level. Our study demonstrated that AKT-mTOR axis is a key mediator of tendon differentiation and provided a novel therapeutic target for tendinopathy and tendon injuries.

Cellular senescence plays both beneficial and detrimental roles in embryonic development and tissue regeneration, while the underlying mechanism remains elusive. Recent studies disclosed the emerging roles of heat‐shock proteins in regulating muscle regeneration and homeostasis. Here, we found that Hsp90β, but not Hsp90α isoform, was significantly upregulated during muscle regeneration. RNA‐seq analysis disclosed a transcriptional elevation of p21 in Hsp90β‐depleted myoblasts, which is due to the upregulation of p53. Moreover, knockdown of Hsp90β in myoblasts resulted in p53‐dependent cellular senescence. In contrast to the notion that Hsp90 interacts with and protects mutant p53 in cancer, Hsp90β preferentially bound to wild‐type p53 and modulated its degradation via a proteasome‐dependent manner. Moreover, Hsp90β interacted with MDM2, the chief E3 ligase of p53, to regulate the stability of p53. In line with these in vitro studies, the expression level of p53‐p21 axis was negatively correlated with Hsp90β in aged mice muscle. Consistently, administration of 17‐AAG, a Hsp90 inhibitor under clinical trial, impaired muscle regeneration by enhancing injury‐induced senescence in vivo. Taken together, our finding revealed a previously unappreciated role of Hsp90β in regulating p53 stability to suppress senescence both in vitro and in vivo.

Two main theories have been used to explain the arithmetic split effect: decision-making process theory and strategy choice theory. Using the inequality paradigm, previous studies have confirmed that individuals tend to adopt a plausibility-checking strategy and a whole-calculation strategy to solve large and small split problems in complex addition arithmetic, respectively. This supports strategy choice theory, but it is unknown whether this theory also explains performance in solving different split problems in complex subtraction arithmetic. This study used small, intermediate and large split sizes, with each split condition being further divided into problems requiring and not requiring borrowing. The reaction times (RTs) for large and intermediate splits were significantly shorter than those for small splits, while accuracy was significantly higher for large and middle splits than for small splits, reflecting no speed-accuracy trade-off. Further, RTs and accuracy differed significantly between the borrow and no-borrow conditions only for small splits. This study indicates that strategy choice theory is suitable to explain the split effect in complex subtraction arithmetic. That is, individuals tend to choose the plausibility-checking strategy or the whole-calculation strategy according to the split size.

The regenerative process of injured muscle is dependent on the fusion and differentiation of myoblasts derived from muscle stem cells. Hsp70 is important for maintaining skeletal muscle homeostasis and regeneration, but the precise cellular mechanism remains elusive. In this study, we found that Hsp70 was upregulated during myoblast differentiation. Depletion or inhibition of Hsp70/Hsc70 impaired myoblast differentiation. Importantly, overexpression of p38 mitogen-activated protein kinase α (p38MAPKα) but not AKT1 rescued the impairment of myogenic differentiation in Hsp70- or Hsc70-depleted myoblasts. Moreover, Hsp70 interacted with MK2, a substrate of p38MAPK, to regulate the stability of p38MAPK. Knockdown of Hsp70 also led to downregulation of both MK2 and p38MAPK in intact muscles and during cardiotoxin-induced muscle regeneration. Hsp70 bound MK2 to regulate MK2-p38MAPK interaction in myoblasts. We subsequently identified the essential regions required for Hsp70-MK2 interaction. Functional analyses showed that MK2 is essential for both myoblast differentiation and skeletal muscle regeneration. Taken together, our findings reveal a novel role of Hsp70 in regulating myoblast differentiation by interacting with MK2 to stabilize p38MAPK.

Background: NPAT is critical for histone transcription and cell cycle progression. Results: A novel NPAT-interacting protein, Cpn10/HSPE, is critical for histone transcription and focus formation of NPAT. Conclusion: Heat shock protein Cpn10 is a novel regulator for histone transcription and cell proliferation. Significance: Our findings reveal a previously unappreciated role of heat shock protein in regulating histone transcription., Precise modulation of histone gene transcription is critical for cell cycle progression. As a direct substrate of Cyclin E/CDK2, nuclear protein ataxia-telangiectasia (NPAT) is a crucial factor in regulating histone transcription and cell cycle progression. Here we identified that Cpn10/HSPE, a 10-kDa heat shock protein, is a novel interacting partner of NPAT. A pool of Cpn10 is colocalized with NPAT foci during G1 and S phases in nuclei. Gain- and loss-of-function experiments unraveled an essential role of Cpn10 in histone transcription. A conserved DLFD motif within Cpn10 was critical for targeting NPAT and modulating histone transcription. More importantly, knockdown of Cpn10 disrupted the focus formation of both NPAT and FADD-like interleukin-1β-converting enzyme-associated huge protein without affecting Coilin-positive Cajal bodies. Finally, Cpn10 is important for S phase progression and cell proliferation. Taken together, our finding revealed a novel role of Cpn10 in the spatial regulation of NPAT signaling and disclosed a previously unappreciated link between the heat shock protein and histone transcription regulation.

Aiming at the features of complexity, poor real-time and Low-accuracy of single-phase Active Power Filter (APF), and the problem of impossible parallel computation in the traditional DSP software realization, new design method of APF Based on FPGA is proposed, This paper focuses on the study of the harmonic current detecting method and improves control method of compensate current, it builds an experimental platform with FPGA EP1C12Q240C8 as the controller, the experimental results all support the effectiveness and correctness of the control methods and design methods of APF.

Two main theories have been used to explain the arithmetic split effect: decision-making process theory and strategy choice theory. Using the inequality paradigm, previous studies have confirmed that individuals tend to adopt a plausibility-checking strategy and a whole-calculation strategy to solve large and small split problems in complex addition arithmetic, respectively. This supports strategy choice theory, but it is unknown whether this theory also explains performance in solving different split problems in complex subtraction arithmetic. This study used small, intermediate and large split sizes, with each split condition being further divided into problems requiring and not requiring borrowing. The reaction times (RTs) for large and intermediate splits were significantly shorter than those for small splits, while accuracy was significantly higher for large and middle splits than for small splits, reflecting no speed-accuracy trade-off. Further, RTs and accuracy differed significantly between the borrow and no-borrow conditions only for small splits. This study indicates that strategy choice theory is suitable to explain the split effect in complex subtraction arithmetic. That is, individuals tend to choose the plausibility-checking strategy or the whole-calculation strategy according to the split size.

The concept of one-protein–multiple-function, i.e. moonlighting proteins, is an ever-expanding paradigm. We obtained compelling evidence that an array of ‘cytoplasmic’ metabolic enzymes can enter the nuclei to carry out moonlighting transcription functions; this phenomenon is conserved from Drosophila to humans. Of particular interest are the classical glycolytic enzymes GAPDH (glyceraldehyde-3-phosphate dehydrogenase) and LDH (lactate dehydrogenase), which utilize NAD(H) as coenzymes and not only moonlight (in their nuclear forms) to regulate the transcription of S-phase-specific histone genes, but also act as metabolic/redox sensors that link histone gene switching to DNA replication and S-phase progression.

Mucopolysaccharidosis type I (MPS-I) is an inborn error of metabolism with progressive multisystem involvement. Hurler syndrome is the most severe form of MPS-I that causes progressive deterioration of the central nervous system with ensuing death. This study reported the therapeutic effect of allogeneic hematopoietic stem cell transplantation (allo-HSCT) on Hurler syndrome in one case. The patient was a 25-month-old boy. He underwent allo-HSCT. The donor was his elder sister whose HLA-B locus was not matching. The reduced-intensity of BuCy conditioning regimen in allo-HSCT for this patient was as follows: busulfan 3.7 mg/kg daily at 9 to 6 days before transplantation, cyclophosphamide 42.8 mg/kg daily at 5 to 2 days before transplantation, and rabbit antithymocyte globulin 3.5 mg/kg daily at 1, 3, 5, and 7 days before transplantation. Human granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood stem cells (CD34+ cells 12.8 x10(6)/kg) were infused and cyclosporine (CSA), short-course methotrexate, daclizumab and mycophenolate mofetil (MMF) were administered to prevent graft-versus-host disease (GVHD). Complete donor-type engraftment was confirmed by Short Tandem Repeat-Polymerase Chain Reaction (STR-PCR) on day 14 after transplantation. Neutrophil and platelet engraftment occurred on days 11 and 19 after transplantation respectively. Only grade I regimen-related toxicity of live and gastrointestinal tract occurred. GVHD and graft failure were not observed. After transplantation, the clinical symptoms and the neurocognitive function were greatly improved in this patient. It was concluded that allo-HSCT was effective for the treatment of MPS-I. The reduced-intensity conditioning regimen was helpful to decrease the regimen-related toxicity. Sufficient immunosuppressive therapy and adequate hematopoietic stem cells infusion may be beneficial to the donor cell engraftment and reducing the incidence of graft failure and GVHD.