It is difficult to achieve minimally invasive injectable cell delivery while maintaining high cell retention and animal survival for in vivo stem cell therapy of myocardial infarction. Here we show that pluripotent stem cell aggregates pre-differentiated into the early cardiac lineage and encapsulated in a biocompatible and biodegradable micromatrix, are suitable for injectable delivery. This method significantly improves the survival of the injected cells by more than six-fold compared with the conventional practice of injecting single cells, and effectively prevents teratoma formation. Moreover, this method significantly enhances cardiac function and survival of animals after myocardial infarction, as a result of a localized immunosuppression effect of the micromatrix and the in situ cardiac regeneration by the injected cells.

Background: Epidemiologic and experimental studies support an association between PM2.5 exposure and insulin resistance (IR). Innate immune cell activation has been suggested to play a role in the pathogenesis of these effects.Objectives: We sought to evaluate the role of CC-chemokine receptor 2 (CCR2) in PM2.5-mediated inflammation and IR.Methods: Wild-type C57BL/6 and CCR2–/– male mice were fed a high-fat diet and exposed to either concentrated ambient PM2.5 or filtered air for 17 weeks via a whole-body exposure system. We evaluated glucose tolerance and insulin sensitivity. At euthanasia, blood, spleen, and visceral adipose tissue (VAT) were collected, and inflammatory cells were measured using flow cytometry. We used standard immunoblots, immunohistochemical methods, and quantitative PCR (polymerase chain reaction) to assess pathways of interest involving insulin signaling, inflammation, and lipid and glucose metabolism in various organs. Vascular function was assessed using myography.Results: PM2.5 exposure resulted in whole-body IR and increased hepatic lipid accumulation in the liver, which was attenuated in CCR2–/– mice by inhibiting SREBP1c-mediated transcriptional programming, decreasing fatty acid uptake, and suppressing p38 MAPK activity. Abnormal phosphorylation levels of AKT, AMPK in VAT, and adipose tissue macrophage content in wild-type mice were not present in CCR2–/– mice. However, the impaired whole-body glucose tolerance and reduced GLUT-4 in skeletal muscle in response to PM2.5 was not corrected by CCR2 deficiency.Conclusions: PM2.5 mediates IR by regulating VAT inflammation, hepatic lipid metabolism, and glucose utilization in skeletal muscle via both CCR2-dependent and -independent pathways. These findings provide new mechanistic links between air pollution and metabolic abnormalities underlying IR.Citation: Liu C, Xu X, Bai Y, Wang TY, Rao X, Wang A, Sun L, Ying Z, Gushchina L, Maiseyeu A, Morishita M, Sun Q, Harkema JR, Rajagopalan S. 2014. Air pollution–mediated susceptibility to inflammation and insulin resistance: influence of CCR2 pathways in mice. Environ Health Perspect 122:17–26; http://dx.doi.org/10.1289/ehp.1306841

Obesity is a growing epidemic in developed countries. Obese individuals are susceptible to comorbidities, including cardiovascular disease and metabolic disorder. Increasing the ability of adipose tissue to expend excess energy could improve protection from obesity. One promising target is microRNA (miR)-155-5p. We demonstrate that deletion of miR-155 (-5p and -3p) in female mice prevents diet-induced obesity. Body weight gain did not differ between wild-type (WT) and miR-155 knockout (KO) mice fed control diet (CD); however, miR-155 KO mice fed high-fat diet (HFD) gained 56% less body weight and 74% less gonadal white adipose tissue (WAT) than WT mice. Enhanced WAT thermogenic potential, brown adipose tissue differentiation, and/or insulin sensitivity might underlie this obesity resistance. Indeed, miR-155 KO mice on HFD had 21% higher heat release than WT HFD mice. Compared to WT adipocytes, miR-155 KO adipocytes upregulated brown (Ucp1, Cidea, Pparg) and white (Fabp4, Pnpla2, AdipoQ, Fasn) adipogenic genes, and glucose metabolism genes (Glut4, Irs1). miR-155 deletion abrogated HFD-induced adipocyte hypertrophy and WAT inflammation. Therefore, miR-155 deletion increases adipogenic, insulin sensitivity, and energy uncoupling machinery, while limiting inflammation in WAT, which together could restrict HFD-induced fat accumulation. Our results identify miR-155 as a novel candidate target for improving obesity resistance.

Summary Exercise improves whole-body metabolic health through adaptations to various tissues including adipose tissue, but the effects of exercise training on the lipidome of white (WAT) and brown (BAT) adipose tissue are unknown. Here, we utilized MS/MSALL shotgun lipidomics to determine the molecular signatures of exercise-induced adaptations to subcutaneous WAT (scWAT) and BAT. Three weeks of exercise-training decreased specific molecular species of phosphatidic acid (PA), phosphatidylcholines (PC), phosphatidylethanolamines (PE), and phosphatidylserines (PS) in scWAT and increased specific molecular species of PC and PE in BAT. Exercise also decreased most triacylglycerols (TAGs) in scWAT and BAT. In summary, exercise-induced changes to the scWAT and BAT lipidome were highly specific to certain molecular lipid species, indicating that changes in tissue lipid content reflects selective remodeling in scWAT and BAT of both phospholipids and glycerol lipids in response to exercise training, thus providing a comprehensive resource for future studies of lipid metabolism pathways.

The tripartite motif (TRIM) gene family is a highly conserved group of E3 ubiquitin ligase proteins that can establish substrate specificity for the ubiquitin-proteasome complex and also have proteasome-independent functions. While several family members were studied previously, it is relatively recent that over 80 genes, based on sequence homology, were grouped to establish the TRIM gene family. Functional studies of various TRIM genes linked these proteins to modulation of inflammatory responses showing that they can contribute to a wide variety of disease states including cardiovascular, neurological and musculoskeletal diseases, as well as various forms of cancer. Given the fundamental role of the ubiquitin-proteasome complex in protein turnover and the importance of this regulation in most aspects of cellular physiology, it is not surprising that TRIM proteins display a wide spectrum of functions in a variety of cellular processes. This broad range of function and the highly conserved primary amino acid sequence of family members, particularly in the canonical TRIM E3 ubiquitin ligase domain, complicates the development of therapeutics that specifically target these proteins. A more comprehensive understanding of the structure and function of TRIM proteins will help guide therapeutic development for a number of different diseases. This review summarizes the structural organization of TRIM proteins, their domain architecture, common and unique post-translational modifications within the family, and potential binding partners and targets. Further discussion is provided on efforts to target TRIM proteins as therapeutic agents and how our increasing understanding of the nature of TRIM proteins can guide discovery of other therapeutics in the future.

Limb girdle muscular dystrophy type 2B (LGMD2B) and other dysferlinopathies are degenerative muscle diseases that result from mutations in the dysferlin gene and have limited treatment options. The dysferlin protein has been linked to multiple cellular functions including a Ca-dependent membrane repair process that reseals disruptions in the sarcolemmal membrane. Recombinant human MG53 protein (rhMG53) can increase the membrane repair process in multiple cell types both in vitro and in vivo. Here, we tested whether rhMG53 protein can improve membrane repair in a dysferlin-deficient mouse model of LGMD2B (B6.129-Dysf/J). We found that rhMG53 can increase the integrity of the sarcolemmal membrane of isolated muscle fibers and whole muscles in a Ca-independent fashion when assayed by a multi-photon laser wounding assay. Intraperitoneal injection of rhMG53 into mice before acute eccentric treadmill exercise can decrease the release of intracellular enzymes from skeletal muscle and decrease the entry of immunoglobulin G and Evans blue dye into muscle fibers in vivo. These results indicate that short-term rhMG53 treatment can ameliorate one of the underlying defects in dysferlin-deficient muscle by increasing sarcolemmal membrane integrity. We also provide evidence that rhMG53 protein increases membrane integrity independently of the canonical dysferlin-mediated, Ca-dependent pathway known to be important for sarcolemmal membrane repair.

Inflammation and oxidative stress play fundamental roles in the pathogenesis of atherosclerosis. Myeloperoxidase has been extensively implicated as a key mediator of inflammatory and redox-dependent processes in atherosclerosis. However, the effect of synthetic myeloperoxidase inhibitors on atherosclerosis has been insufficiently studied. In this study, ApoE−/− mice were randomized to low- and high-dose INV-315 groups for 16 weeks on high-fat diet. INV-315 resulted in reduced plaque burden and improved endothelial function in response to acetylcholine. These effects occurred without adverse events or changes in body weight or blood pressure. INV-315 treatment resulted in a decrease in iNOS gene expression, superoxide production and nitrotyrosine content in the aorta. Circulating IL-6 and inflammatory CD11b+/Ly6Glow/7/4hi monocytes were significantly decreased in response to INV-315 treatment. Acute pretreatment with INV-315 blocked TNFα-mediated leukocyte adhesion in cremasteric venules and inhibited myeloperoxidase activity. Cholesterol efflux was significantly increased by high-dose INV-315 via ex-vivo reverse cholesterol transport assays. Our results suggest that myeloperoxidase inhibition may exert anti-atherosclerotic effects via inhibition of oxidative stress and enhancement of cholesterol efflux. These findings demonstrate a role for pharmacologic modulation of myeloperoxidase in atherosclerosis.

Scope Three fluorescence biosensors were developed based on a 3T3-L1 preadipocyte line that stably expressed Nfkb-RE/GFP, Fabp4-P/CFP, and Nrf2-P/YFP fluorescent reporters. We hypothesized that nutraceuticals’ inflammatory, adipogenic, and antioxidant status will be identified based on the change in fluorescence in reporter adipocytes. We validated these assays with activators of NFκB, FABP4-regulating PPARγ, NFR2 and, thereafter, tested known and unknown properties of mangosteens (MG), the xanthone metabolites in mangosteen fruit. Methods and results We validated inflammatory and adipogenic properties of α-MG using a Nfkb-RE/GFP biosensor assay. Next, we identified unique properties of γ-MG, a minor mangosteen xanthone. γ-MG suppressed adipogenesis and adiponectin, but inhibited the Nfkb-RE/GFP reporter and secretion of inflammatory MCP-1 as compared to the control adipocytes. We found that the inhibition of adipogenesis and Nfkb-mediated inflammation depends on a dose-dependent reduction of Nrf2 promoter activity by α-MG. The Nrf2 inhibition resulted in the reduced Pparg expression. α-MG did not directly influence Pparg activity in Fabp4-P/CFP adipocytes. Conclusion α-MG-mediated antioxidant response via Nrf2 is a mechanism preventing adipogenesis and inflammation in adipocytes. Combined application of high-throughput biosensors could provide an effective platform for the identification of nutraceuticals and the mechanism of their actions in adipocytes and, potentially, in obese patients.