Project description:Mitochondrial health declines with age, and older patients can demonstrate dysfunction in mitochondrial-rich tissues, such as cardiac and skeletal muscle. Aged mitochondria may make older adults more susceptible to adverse drug reactions (ADRs). We assessed mitochondrial metabolic function by measuring two metabolites, l-carnitine and acetylcarnitine, to determine their effectiveness as candidate clinical biomarkers for age-related, drug-induced alterations in mitochondrial metabolism. To study age- and medication-related changes in mitochondrial metabolism, we administered the FDA-approved mitochondriotropic drug, clofazimine (CFZ), or vehicle for 8 weeks to young (4-week-old) and old (61-week-old) male C57BL/6J mice. At the end of treatment, whole blood and cardiac and skeletal muscle were analyzed for l-carnitine, acetylcarnitine, and CFZ levels; muscle function was measured via a treadmill test. No differences were found in blood or cardiac carnitine levels of CFZ-treated mice, but CFZ-treated mice displayed lost body mass and alterations in endurance and levels of skeletal muscle mitochondrial metabolites. These findings demonstrate the age-related susceptibility of the skeletal muscle to mitochondria drug toxicity. Since drug-induced alterations in mitochondrial metabolism in skeletal muscle were not reflected in the blood by l-carnitine or acetylcarnitine levels, drug-induced catabolism and changes in muscle function appear more relevant to stratifying individuals at increased risk for ADRs.
Project description:Expression of bone morphogenetic protein 4 (BMP4) in adipocytes of white adipose tissue (WAT) produces "white adipocytes" with characteristics of brown fat and leads to a reduction of adiposity and its metabolic complications. Although BMP4 is known to induce commitment of pluripotent stem cells to the adipocyte lineage by producing cells that possess the characteristics of preadipocytes, its effects on the mature white adipocyte phenotype and function were unknown. Forced expression of a BMP4 transgene in white adipocytes of mice gives rise to reduced WAT mass and white adipocyte size along with an increased number of a white adipocyte cell types with brown adipocyte characteristics comparable to those of beige or brite adipocytes. These changes correlate closely with increased energy expenditure, improved insulin sensitivity, and protection against diet-induced obesity and diabetes. Conversely, BMP4-deficient mice exhibit enlarged white adipocyte morphology and impaired insulin sensitivity. We identify peroxisome proliferator-activated receptor gamma coactivator 1-? (PGC1?) as the target of BMP signaling required for these brown fat-like changes in WAT. This effect of BMP4 on WAT appears to extend to human adipose tissue, because the level of expression of BMP4 in WAT correlates inversely with body mass index. These findings provide a genetic and metabolic basis for BMP4's role in altering insulin sensitivity by affecting WAT development.
Project description:Various environmental factors can alter the gut microbiome's composition and functionality, and modulate host health. In this study, the effects of oral and parenteral administration of two poorly bioavailable antibiotics (i.e., vancomycin and streptomycin) on male Wistar Crl/Wi(Han) rats for 28 days were compared to distinguish between microbiome-derived or -associated and systemic changes in the plasma metabolome. The resulting changes in the plasma metabolome were compared to the effects of a third reference compound, roxithromycin, which is readily bioavailable. A community analysis revealed that the oral administration of vancomycin and roxithromycin in particular leads to an altered microbial population. Antibiotic-induced changes depending on the administration routes were observed in plasma metabolite levels. Indole-3-acetic acid (IAA) and hippuric acid (HA) were identified as key metabolites of microbiome modulation, with HA being the most sensitive. Even though large variations in the plasma bile acid pool between and within rats were observed, the change in microbiome community was observed to alter the composition of the bile acid pool, especially by an accumulation of taurine-conjugated primary bile acids. In-depth investigation of the relationship between microbiome variability and their functionality, with emphasis on the bile acid pool, will be necessary to better assess the potential adverseness of environmentally induced microbiome changes.
Project description:BackgroundCancer cachexia is a metabolic disorder involving perturbed energy balance and altered mitochondrial function. Chemotherapy is a primary treatment option for many types of cancer, but there is substantial evidence that some chemotherapeutic agents can also lead to the development and progression of cachexia. In this study, we apply a comprehensive and systems level metabolomics approach to characterize the metabolic perturbations in murine models of cancer-induced and chemotherapy-induced cachexia. Knowledge of the unique pathways through which cancer and chemotherapy drive cachexia is necessary in order to develop effective treatments.MethodsThe murine Colon26 (C26) adenocarcinoma xenograft model was used to study the metabolic derangements associated with cancer-induced cachexia. In vivo administration of Folfiri (5-fluorouracil, irinotecan, and leucovorin) was used to model chemotherapy-induced cachexia. Comprehensive metabolic profiling was carried out using both nuclear magnetic resonance-based and mass spectrometry-based platforms. Analyses included plasma, muscle, and liver tissue to provide a systems level profiling.ResultsThe study involved four groups of CD2F1 male mice (n = 4-5), including vehicle treated (V), C26 tumour hosts (CC), Folfiri treated (F), and C26 tumour hosts treated with Folfiri (CCF). Significant weight loss including skeletal muscle was observed for each of the experimental groups with the tumour hosts showing the most dramatic change (-3.74 g vs. initial body weight in the CC group). Skeletal muscle loss was evident in all experimental groups compared with V, with the CCF combination resulting in the most severe depletion of quadriceps mass (-38% vs. V; P < 0.001). All experimental groups were characterized by an increased systemic glucose demand as evidenced by decreased levels of circulating glucose (-47% in CC vs. V; P < 0.001) and depletion of liver glucose (-51% in CC vs. V; P < 0.001) and glycogen (-74% in CC vs. V; P < 0.001). The cancer-induced and chemotherapy-induced cachexia models displayed unique alterations in flux through the tricarboxylic acid cycle and β-oxidation pathways. Cancer-induced cachexia was uniquely characterized by a dramatic elevation in low-density lipoprotein particles (+6.9-fold vs. V; P < 0.001) and a significant increase in the inflammatory marker, GlycA (+33% vs. V; P < 0.001).ConclusionsThe results of this study demonstrated for the first time that cancer-induced and chemotherapy-induced cachexia is characterized by a number of distinct metabolic derangements. Effective therapeutic interventions for cancer-induced and chemotherapy-induced cachexia must take into account the specific metabolic defects imposed by the pathological or pharmacological drivers of cachexia.
Project description:The cocktails of antibiotics are utilized to study the functions of microbiota. There have been studies on the alteration of not only the microbiota composition but also the host's metabolism or immunity. However, the bacterial species associated with these altered physiologic markers are still unclear. Therefore, we supplied mice with drinking water containing ampicillin (AMP), vancomycin (VAN), neomycin (NEO), or metronidazole (MET) to observe the effect of each antibiotic on helper T cells and inflammation-related gene expression and metabolism, including amino acid metabolism and changes in gut microbiota. We observed major changes in gut microbiota in mice treated with AMP and VAN, respectively, immediately after administration. The abundance of the genera Parabacteroides and Akkermansia increased in the AMP and VAN groups, while Prevotella almost disappeared from both groups. The compositional changes in intestinal metabolites in the AMP and VAN groups were more distinct than those in the NEO and MET groups, which was similar to the microbiome results. In particular, the most distinct changes were observed in amino acid related metabolism in AMP and VAN groups; the amounts of phenylalanine and tyrosine were increased in the AMP group while those were decreased in the VAN group. The changed amounts of intestinal amino acids in each of the AMP and VAN groups were correlated with increases in the abundance of the genera Parabacteroides and Akkermansia in the AMP and VAN groups, respectively. The most distinctive changes in intestinal gene expression were observed in the ileum, especially the expression Th17-related genes such as rorgt, il17a, and il17f, which decreased dramatically in the guts of most of the antibiotic-treated groups. These changes were also associated with a significant decrease in Prevotella in both the AMP and VAN groups. Taken together, these findings indicate that changes in gut microbiota as well as host physiology, including host metabolism and immunity, differ depending on the types of antibiotics, and the antibiotic-induced gut microbiota alteration has a correlation with host physiology such as host metabolic or immunological status. Thus, the immune and metabolic status of the host should be taken into account when administering antibiotics.
Project description:Long chain acyl-CoA synthetases (ACSL) catalyze long-chain fatty acids (FA) conversion to acyl-CoAs. Temporal ACSL1 inactivation in mouse hearts (Acsl1(H-/-)) impaired FA oxidation and dramatically increased glucose uptake, glucose oxidation, and mTOR activation, resulting in cardiac hypertrophy. We used unbiased metabolomics and gene expression analyses to elucidate the cardiac cellular response to increased glucose use in a genetic model of inactivated FA oxidation. Metabolomics analysis identified 60 metabolites altered in Acsl1(H-/-) hearts, including 6 related to glucose metabolism and 11 to cysteine and glutathione pathways. Concurrently, global cardiac transcriptional analysis revealed differential expression of 568 genes in Acsl1(H-/-) hearts, a subset of which we hypothesized were targets of mTOR; subsequently, we measured the transcriptional response of several genes after chronic mTOR inhibition via rapamycin treatment during the period in which cardiac hypertrophy develops. Hearts from Acsl1(H-/-) mice increased expression of several Hif1α-responsive glycolytic genes regulated by mTOR; additionally, expression of Scl7a5, Gsta1/2, Gdf15, and amino acid-responsive genes, Fgf21, Asns, Trib3, Mthfd2, were strikingly increased by mTOR activation. The switch from FA to glucose use causes mTOR-dependent alterations in cardiac metabolism. We identified cardiac mTOR-regulated genes not previously identified in other cellular models, suggesting heart-specific mTOR signaling. Increased glucose use also changed glutathione-related pathways and compensation by mTOR. The hypertrophy, oxidative stress, and metabolic changes that occur within the heart when glucose supplants FA as a major energy source suggest that substrate switching to glucose is not entirely benign.
Project description:ObjectiveThe sites of insulin action in the central nervous system that regulate glucose metabolism and energy expenditure are incompletely characterized. We have shown that mice with hypothalamic deficiency (L1) of insulin receptors (InsRs) fail to regulate hepatic glucose production (HGP) in response to insulin.Research design and methodsTo distinguish neurons that mediate insulin's effects on HGP from those that regulate energy homeostasis, we used targeted knock-ins to express InsRs in agouti-related protein (AgRP) or proopiomelanocortin (POMC) neurons of L1 mice.ResultsRestoration of insulin action in AgRP neurons normalized insulin suppression of HGP. Surprisingly, POMC-specific InsR knock-in increased energy expenditure and locomotor activity, exacerbated insulin resistance and increased HGP, associated with decreased expression of the ATP-sensitive K(+) channel (K(ATP) channel) sulfonylurea receptor 1 subunit, and decreased inhibitory synaptic contacts on POMC neurons.ConclusionsThe contrasting phenotypes of InsR knock-ins in POMC and AgRP neurons suggest a branched-pathway model of hypothalamic insulin signaling in which InsR signaling in AgRP neurons decreases HGP, whereas InsR activation in POMC neurons promotes HGP and activates the melanocortinergic energy expenditure program.
Project description:Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer-related deaths in the US. Cancer-associated cachexia is present in up to 80% of PDAC patients and is associated with aggressive disease and poor prognosis. In the present studies we evaluated an anti-cancer natural product silibinin for its effectiveness in targeting pancreatic cancer aggressiveness and the cachectic properties of pancreatic cancer cells and tumors. Our results demonstrate that silibinin inhibits pancreatic cancer cell growth in a dose-dependent manner and reduces glycolytic activity of cancer cells. Our LC-MS/MS based metabolomics data demonstrates that silibinin treatment induces global metabolic reprogramming in pancreatic cancer cells. Silibinin treatment diminishes c-MYC expression, a key regulator of cancer metabolism. Furthermore, we observed reduced STAT3 signaling in silibinin-treated cancer cells. Overexpression of constitutively active STAT3 was sufficient to substantially revert the silibinin-induced downregulation of c-MYC and the metabolic phenotype. Our in vivo investigations demonstrate that silibinin reduces tumor growth and proliferation in an orthotopic mouse model of pancreatic cancer and prevents the loss of body weight and muscle. It also improves physical activity including grip strength and latency to fall in tumor-bearing mice. In conclusion, silibinin-induced metabolic reprogramming diminishes cell growth and cachectic properties of pancreatic cancer cells and animal models.
Project description:During the torpor phase of mammalian hibernation when core body temperature is near 4 degrees C, the autonomic system continues to maintain respiration, blood pressure and heartbeat despite drastic reductions in brain activity. In addition, the hibernator's neuronal tissues enter into a protected state in which the potential for ischemia-reperfusion injury is markedly minimized. Evolutionary adaptations for continued function and neuroprotection throughout cycles of torpor and euthermia in winter are predicted to manifest themselves partly in changes in the brainstem proteome. Here, we compare the soluble brainstem protein complement from six summer active ground squirrels and six in the early torpor (ET) phase of hibernation. Thirteen percent of the approximately 1,500 quantifiable 2D gel spots alter significantly from summer to ET; the proteins identified in these differing spots are known to play roles in energy homeostasis via the tricarboxylic acid cycle (8 proteins), cytoarchitecture and cell motility (14 proteins), anabolic protein processes (13 proteins), redox control (11 proteins) and numerous other categories including protein catabolism, oxidative phosphorylation, signal transduction, glycolysis, intracellular protein trafficking and antiapoptotic function. These protein changes represent, at least in part, the molecular bases for restructuring of cells in the brainstem, a shift away from glucose as the primary fuel source for brain in the winter, and the generation of a streamlined mechanism capable of efficient and rapid energy production and utilization during the torpor and arousal cycles of hibernation.
Project description:Type 2 diabetes is characterized by a deterioration of glucose tolerance, which associates insulin resistance of glucose uptake by peripheral tissues and increased endogenous glucose production. Here we report that the specific suppression of hepatic glucose production positively modulates whole-body glucose and energy metabolism. We used mice deficient in liver glucose-6 phosphatase that is mandatory for endogenous glucose production. When they were fed a high fat/high sucrose diet, they resisted the development of diabetes and obesity due to the activation of peripheral glucose metabolism and thermogenesis. This was linked to the secretion of hepatic hormones like fibroblast growth factor 21 and angiopoietin-like factor 6. Interestingly, the deletion of hepatic glucose-6 phosphatase in previously obese and insulin-resistant mice resulted in the rapid restoration of glucose and body weight controls. Therefore, hepatic glucose production is an essential lever for the control of whole-body energy metabolism during the development of obesity and diabetes.