Adiponectin receptor 1 overexpression reduces lipid accumulation and hypertrophy in the heart of diet-induced obese mice--possible involvement of oxidative stress and autophagy.

BACKGROUND: Studies show that adiponectin and its receptors (AdipoR1 and 2) play important roles in regulating glucose and lipid metabolism in mice. Obesity, type II diabetes and cardiovascular disease are highly correlated with downregulated adiponectin signaling; however, research has not clarified the functions of AdipoR1 in vivo. METHODS: In this study, mice were induced to overexpress the AdipoR1 transgene so that its functions could be studied in relation to hypertrophic cardiomyopathy. Wild-type and AdipoR1-transgenic male mice were fed ad libitum with a standard chow diet or else a high-fat/sucrose diet (HFSD) for 24 weeks, beginning at 6-7 weeks of age. RESULTS: After receiving the 24-week HFSD, AdipoR1-transgenic mice did not become obese, nor did they develop heart hypertrophy. The AdipoR1 transgene decreased the elevating cardiac troponin I expression caused by the HFSD. While the HFSD induced mRNA expression of CD36 and CPTI, AdipoR1 reversed it. Suppression of cardiac SOD mRNA expression by the HFSD was improved by the AdipoR1 transgene. The HFSD caused a higher autophagic gene expression of Beclin 1 and Lamp 2 A in the heart, whereas the AdipoR1 transgene ameliorated them. CONCLUSIONS: The AdipoR1 transgene enabled mice to resist diet-induced obesity while decreasing lipid accumulation, oxidative stress and autophagic damage. These effects might contribute to the improvement of heart functions in diet-induced obese mice.

Modulation of glucose and lipid metabolism by porcine adiponectin receptor 1-transgenic mesenchymal stromal cells in diet-induced obese mice.

BACKGROUND AIMS: Obesity and its associated diseases demand better therapeutic strategies. Regenerative medicine combined with gene therapy has emerged as a promising approach in various clinical applications. Adiponectin (ApN) and its receptors have been demonstrated to play beneficial roles in modulating glucose and lipid homeostasis. In the current study, we tested such an approach by transplanting mesenchymal stromal cells (MSCs) from porcine ApN receptor (pAdipoR) 1-transgenic mice into high-fat/sucrose diet (HFSD)-fed mice. METHODS: Twenty 6-week-old Friend virus B/NJNarl male mice were randomly assigned into four groups with the control fed a chow diet (chow) and others HFSD for 10 months. The HFSD groups were then intraperitoneally injected once per week for 8 weeks with placebo (200 µL phosphate-buffered saline), wild-type MSC (WT-MSC, 2 × 10(6) cells/200 µL phosphate-buffered saline) or pAdipoR1-transgenic MSC (pR1-tMSC, 2 × 10(6) cells/200 µL phosphate-buffered saline), respectively. Body weights, blood samples, tissue histology, and gene expression and protein levels of metabolism-associated genes were analyzed. RESULTS: Both WT-MSC and pR1-tMSC transplantations restored the messenger RNA expression of AdipoR1, with those of glucose transporter 4 and 5'-adenosine monophosphate-activated protein kinase catalytic subunit α-1 and protein levels of pyruvate kinase induced by pR1-tMSC in the muscles of HFSD-fed mice. In the liver, both WT-MSC and pR1-tMSC ameliorated HFSD-induced hepatosteatosis, with the gene expression of lipoprotein lipase and hormone-sensitive lipase upregulated by the latter. Lastly, pR1-tMSC transplantation reduced fatty acid synthase mRNA levels in the adipose tissues of HFSD-fed mice. CONCLUSIONS: This study demonstrates the modulatory actions of MSC and pR1-tMSC on genes associated with glucose and lipid metabolism and provides insights into its therapeutic application for obesity-associated metabolic complication.

Localization effect on the metal biosorption capability of recombinant mammalian and fish metallothioneins in Escherichia coli.

In this study, we examined the expression of mammalian and fish metallothioneins (MTs) in Escherichia coli as a strategy to enhance metal biosorption efficiency of bacterial biosorbents for lead (Pb), copper (Cu), cadmium (Cd), and zinc (Zn). In addition, MT proteins were expressed in either the cytoplasmic or periplasmic compartment of host cells to explore the localization effect on metal biosorption. The results showed that MT expression led to a significant increase (5-210%) in overall biosorption efficiency (eta(ads)), especially for biosorption of Cd. The MT-driven improvement in metal biosorption relied more on the increase in the biosorption rates (r(2), a kinetic property) than on the equilibrium biosorption capacities (q(max), a thermodynamic property), despite a 10-45% and 30-80% increase in q(max) of Cd and Zn, respectively. Periplasmic expression of MTs appeared to be more effective in facilitating the metal-binding ability than the cytoplasmlic MT expression. Notably, disparity of the impacts on biosorption ability was observed for the origin of MT proteins, as human MT (MT1A) was the most effective biosorption stimulator compared to MTs originating from mouse (MT1) and fish (OmMT). Moreover, the overall biosorption efficiency (eta(ads)) of the MT-expressing recombinant biosorbents was found to be adsorbate-dependent: the eta(ads) values decreased in the order of Cd > Cu > Zn > Pb.