Prevalence and Health Associations of Meeting the World Health Organization Guidelines for Physical Activity, Sedentary Behavior, and Sleep in Preschool-Aged Children: The SUNRISE Mongolia Pilot and Feasibility Study.

BACKGROUND: There is a lack of evidence regarding 24-hour movement behaviors of young children from low- and middle-income countries. This study examined Mongolian preschoolers' adherence to the World Health Organization's guidelines for physical activity, sedentary behavior, and sleep; their associations with health indicators, and the feasibility of the SUNRISE International study in Mongolia. METHODS: Preschool-aged children were recruited from 5 kindergartens in urban and rural areas of Ulaanbaatar city and Tuv province in Mongolia. Physical activity and sedentary behavior were measured by an ActiGraph accelerometer worn for 5 consecutive days. Screen time and sleep were reported by parents. The National Institute of Health and Early Years Toolboxes were used to assess motor skills and executive function, respectively. RESULTS: One hundred and one children participated in the study (mean age = 4.82 y, boys = 58), with 88% (n = 89) having complete data for analysis. The proportion of children who met the recommendations for physical activity, sedentary screen time, and sleep was 61%, 23%, and 82%, respectively. Only 7% met all recommendations. Meeting the sleep recommendation individually (P = .032) and in combination with the physical activity recommendation was associated with better gross (P = .019) and fine (P = .042) motor skills. Spending more time in physical activity was positively correlated with motor development. Results confirmed that the SUNRISE study protocol was feasible, age-appropriate, and enjoyable for children. CONCLUSIONS: The results of the SUNRISE pilot study will help inform the SUNRISE Mongolia main study and lay the groundwork for future research into children's 24-hour movement behaviors in Mongolia.

Cysteine string protein 1 (CSP1) modulates insulin sensitivity by attenuating glucose transporter 4 (GLUT4) vesicle docking with the plasma membrane.

Insulin stimulates glucose transporter 4 (GLUT4) vesicle recruitment from its intracellular storage site to the plasma membrane. Cysteine string protein 1 (CSP1) is a SNARE-binding protein involved in the vesicular trafficking of neurotransmitters and other exocytic processes. In this study, we investigated the involvement of CSP1 in insulin-dependent GLUT4 recruitment in 3T3-L1 adipocytes. Over-expression of wild-type CSP1 led to attenuated insulin-stimulated glucose uptake without any change in GLUT4 content in the plasma membrane, rather it inhibits docking by blocking the association of VAMP2 with syntaxin 4. In contrast, knockdown of CSP1 enhanced insulin-stimulated glucose uptake. The mRNA and protein expression of CSP1 was elevated in 3T3-L1 adipocytes in insulin resistant states caused by high levels of palmitate and chronic insulin exposure. Taken together, the results of this study suggest that CSP1 is involved in insulin resistance by interrupting GLUT4 vesicle docking with the plasma membrane.

Vimentin binds IRAP and is involved in GLUT4 vesicle trafficking.

Insulin-responsive aminopeptidase (IRAP) and GLUT4 are two major cargo proteins of GLUT4 storage vesicles (GSVs) that are translocated from a postendosomal storage compartment to the plasma membrane (PM) in response to insulin. The cytoplasmic region of IRAP is reportedly involved in retention of GSVs. In this study, vimentin was identified using the cytoplasmic domain of IRAP as bait. The validity of this interaction was confirmed by pull-down assays and immunoprecipitation in 3T3-L1 adipocytes. In addition, it was shown that GLUT4 translocation to the PM by insulin was decreased in vimentin-depleted adipocytes, presumably due to dispersing GSVs away from the cytoskeleton. These findings suggest that the IRAP binding protein, vimentin, plays an important role in retention of GSVs.

Long-term treatment with hyperbaric air improves hyperlipidemia of db/db mice.

Hyperbaric air (HBA) is used to improve healing of wounds including diabetic ulcer. The aim of this study was to clarify the effects of HBA exposure on lipid and glucose metabolism in db/db mice. HBA did not influence the weight of db/db mice. Serum levels of free fatty acid and triglyceride, but not glucose and insulin, were significantly decreased after 6 weeks of treatment with HBA. The mRNA expressions of CPT-1, PPARα and PGC-1α genes, which are related to lipid metabolism, were significantly up-regulated in the muscle and liver. Increases in TNFα and MCP1 mRNA, which impaired lipid metabolism, were also attenuated by HBA treatment. These results suggest that exposure of HBA could have beneficial effects on lipid metabolism in patients with type 2 diabetes mellitus.

Myosin IIA participates in docking of Glut4 storage vesicles with the plasma membrane in 3T3-L1 adipocytes.

In adipocytes and myocytes, insulin stimulation translocates glucose transporter 4 (Glut4) storage vesicles (GSVs) from their intracellular storage sites to the plasma membrane (PM) where they dock with the PM. Then, Glut4 is inserted into the PM and initiates glucose uptake into these cells. Previous studies using chemical inhibitors demonstrated that myosin II participates in fusion of GSVs and the PM and increase in the intrinsic activity of Glut4. In this study, the effect of myosin IIA on GSV trafficking was examined by knocking down myosin IIA expression. Myosin IIA knockdown decreased both glucose uptake and exposures of myc-tagged Glut4 to the cell surface in insulin-stimulated cells, but did not affect insulin signal transduction. Interestingly, myosin IIA knockdown failed to decrease insulin-dependent trafficking of Glut4 to the PM. Moreover, in myosin IIA knockdown cells, insulin-stimulated binding of GSV SNARE protein, vesicle-associated membrane protein 2 (VAMP2) to PM SNARE protein, syntaxin 4 was inhibited. These data suggest that myosin IIA plays a role in insulin-stimulated docking of GSVs to the PM in 3T3-L1 adipocytes through SNARE complex formation.