{
"METABOLOMICS WORKBENCH":{"STUDY_ID":"ST003005","ANALYSIS_ID":"AN004936","VERSION":"1","CREATED_ON":"12-14-2023"},

"PROJECT":{"PROJECT_TITLE":"Uncoupling Metabolic Health from Thermogenesis via BCAA Flux in Brown Fat","PROJECT_TYPE":"MS quantitative analysis","PROJECT_SUMMARY":"Brown adipose tissue (BAT) is best known for thermogenesis. Whereas numerous studies in rodents found tight associations between the metabolic benefits of BAT and enhanced whole-body energy expenditure, emerging evidence in humans suggests that BAT is protective against Type 2 diabetes independent of body-weight. The underlying mechanism for this dissociation remained unclear. Here, we report that impaired mitochondrial flux of branched-chain amino acids (BCAA) in BAT, by deleting mitochondrial BCAA carrier (MBC, encoded by Slc25a44), was sufficient to cause systemic insulin resistance without affecting whole-body energy expenditure or body-weight. We found that brown adipocytes catabolized BCAAs in the mitochondria as essential nitrogen donors for the biosynthesis of glutamate, N-acetylated amino acids, and one of the products, glutathione. BAT-selective impairment in mitochondrial BCAA flux led to elevated oxidative stress and insulin resistance in the liver, accompanied by reduced levels of BCAA-derived metabolites in the circulation. In turn, supplementation of glutathione restored insulin sensitivity of BAT-specific MBC knockout mice. Notably, a high-fat diet rapidly impaired BCAA catabolism and the synthesis of BCAA-nitrogen derived metabolites in the BAT, while cold-induced BAT activity is coupled with an active synthesis of these metabolites. Together, the present work uncovers a mechanism through which brown fat controls metabolic health independent of thermogenesis via BCAA-derived nitrogen carriers acting on the liver.","INSTITUTE":"Harvard Medical School","LAST_NAME":"Wang","FIRST_NAME":"Dandan","ADDRESS":"3 Blackfan Circle, Boston, MA, 02115, USA","EMAIL":"dandanwang2022@gmail.com","PHONE":"5083733714","DOI":"http://dx.doi.org/10.21228/M8MF0Z"},

"STUDY":{"STUDY_TITLE":"Brown fat metabolomics of Chow and HFD diet","STUDY_SUMMARY":"Brown adipose tissue (BAT) metabolites in mice fed a standard diet or a high-fat diet for 12 weeks. N = 6 per group.","INSTITUTE":"Harvard Medical School","LAST_NAME":"Wang","FIRST_NAME":"Dandan","ADDRESS":"3 Blackfan Circle, Boston, MA, 02115, USA","EMAIL":"dandanwang2022@gmail.com","PHONE":"5083733714","SUBMIT_DATE":"2023-12-12"},

"SUBJECT":{"SUBJECT_TYPE":"Mammal","SUBJECT_SPECIES":"Mus musculus","TAXONOMY_ID":"10090","GENOTYPE_STRAIN":"C57BL/6J","AGE_OR_AGE_RANGE":"12 weeks","WEIGHT_OR_WEIGHT_RANGE":"25-30g","GENDER":"Male"},
"SUBJECT_SAMPLE_FACTORS":[
{
"Subject ID":"-",
"Sample ID":"BAT_chow_neg_1",
"Factors":{"Diet":"Chow"},
"Additional sample data":{"Sample type":"Tissue","RAW_FILE_NAME":"BAT_chow_neg_1.RAW"}
},
{
"Subject ID":"-",
"Sample ID":"BAT_chow_neg_2",
"Factors":{"Diet":"Chow"},
"Additional sample data":{"Sample type":"Tissue","RAW_FILE_NAME":"BAT_chow_neg_2.RAW"}
},
{
"Subject ID":"-",
"Sample ID":"BAT_chow_neg_3",
"Factors":{"Diet":"Chow"},
"Additional sample data":{"Sample type":"Tissue","RAW_FILE_NAME":"BAT_chow_neg_3.RAW"}
},
{
"Subject ID":"-",
"Sample ID":"BAT_chow_neg_4",
"Factors":{"Diet":"Chow"},
"Additional sample data":{"Sample type":"Tissue","RAW_FILE_NAME":"BAT_chow_neg_4.RAW"}
},
{
"Subject ID":"-",
"Sample ID":"BAT_chow_neg_5",
"Factors":{"Diet":"Chow"},
"Additional sample data":{"Sample type":"Tissue","RAW_FILE_NAME":"BAT_chow_neg_5.RAW"}
},
{
"Subject ID":"-",
"Sample ID":"BAT_chow_neg_6",
"Factors":{"Diet":"Chow"},
"Additional sample data":{"Sample type":"Tissue","RAW_FILE_NAME":"BAT_chow_neg_6.RAW"}
},
{
"Subject ID":"-",
"Sample ID":"BAT_HFD_neg_1",
"Factors":{"Diet":"HFD"},
"Additional sample data":{"Sample type":"Tissue","RAW_FILE_NAME":"BAT_HFD_neg_1.RAW"}
},
{
"Subject ID":"-",
"Sample ID":"BAT_HFD_neg_2",
"Factors":{"Diet":"HFD"},
"Additional sample data":{"Sample type":"Tissue","RAW_FILE_NAME":"BAT_HFD_neg_2.RAW"}
},
{
"Subject ID":"-",
"Sample ID":"BAT_HFD_neg_3",
"Factors":{"Diet":"HFD"},
"Additional sample data":{"Sample type":"Tissue","RAW_FILE_NAME":"BAT_HFD_neg_3.RAW"}
},
{
"Subject ID":"-",
"Sample ID":"BAT_HFD_neg_4",
"Factors":{"Diet":"HFD"},
"Additional sample data":{"Sample type":"Tissue","RAW_FILE_NAME":"BAT_HFD_neg_4.RAW"}
},
{
"Subject ID":"-",
"Sample ID":"BAT_HFD_neg_5",
"Factors":{"Diet":"HFD"},
"Additional sample data":{"Sample type":"Tissue","RAW_FILE_NAME":"BAT_HFD_neg_5.RAW"}
},
{
"Subject ID":"-",
"Sample ID":"BAT_HFD_neg_6",
"Factors":{"Diet":"HFD"},
"Additional sample data":{"Sample type":"Tissue","RAW_FILE_NAME":"BAT_HFD_neg_6.RAW"}
}
],
"COLLECTION":{"COLLECTION_SUMMARY":"Animals were sacrificed immediately by cervical dislocation and tissues were rapidly extracted and immediately snap frozen in liquid nitrogen for metabolite profiling.","SAMPLE_TYPE":"Brown fat tissue"},

"TREATMENT":{"TREATMENT_SUMMARY":"All mice were housed under a 12 h – 12 h light/dark cycle. Room-temperature mice were housed at 23˚C in ventilated cages with an ACH of 25. Mice were fed a standard diet (Lab Diet 5008) or high-fat diet (Research Diets; D12492; 60% Fat) and had free access to food and water."},

"SAMPLEPREP":{"SAMPLEPREP_SUMMARY":"Animals were sacrificed immediately by cervical dislocation and tissues were rapidly extracted and immediately snap frozen in liquid nitrogen for metabolite profiling. For metabolite extraction, tissues were weighed and then homogenized with extraction buffer which consisted of 80% methanol containing D₈-Phenylalanine internal standards at a 40:1 volume to wet weight ratio. Samples were centrifuged at 16,000 x g at 4 °C for 15 min. Finally, 50 μL supernatant was transferred to the glass insert for LC-MS detection."},

"CHROMATOGRAPHY":{"INSTRUMENT_NAME":"Thermo Vanquish","COLUMN_NAME":"Waters ACQUITY UPLC BEH Amide (100 x 2.1mm,1.7um)","COLUMN_TEMPERATURE":"25 °C","FLOW_GRADIENT":"The linear gradient eluted from 95% B (0.0–1 min), 95% B to 65% B (1–7.0 min), 65% B to 40% B (7.0–8.0 min), 40% B (8.0–9.0 min), 40% B to 95% B (9.0–9.1 min), then stayed at 95% B for 5.9 min.","FLOW_RATE":"0.4 mL/min","SOLVENT_A":"100% water; 25mM ammonium acetate; 25mM ammonium hydroxide","SOLVENT_B":"100% acetonitrile","CHROMATOGRAPHY_TYPE":"HILIC"},

"ANALYSIS":{"ANALYSIS_TYPE":"MS"},

"MS":{"INSTRUMENT_NAME":"Thermo orbitrap exploris 240","INSTRUMENT_TYPE":"Orbitrap","MS_TYPE":"ESI","MS_COMMENTS":"ESI source parameters were set as follows: spray voltage, 3500 V or −2800 V, in positive or negative modes, respectively; vaporizer temperature, 350 °C; sheath gas, 50 arb; aux gas, 10 arb; ion transfer tube temperature, 325 °C. The full scan was set as: orbitrap resolution, 60,000; maximum injection time, 100 ms; scan range, 70–1050 Da. The ddMS2 scan was set as: orbitrap resolution, 30,000; maximum injection time, 60 ms; top N setting, 6; isolation width, 1.0 m/z; HCD collision energy (%), 30; Dynamic exclusion mode was set as auto. The data was analyzed by Compound Discoverer 3.3.","ION_MODE":"NEGATIVE","MS_RESULTS_FILE":"ST003005_AN004936_Results.txt UNITS:Peak area Has m/z:Yes Has RT:Yes RT units:Minutes"}

}