Browsing by Author "Wang, Linshu"
Now showing 1 - 4 of 4
- Results Per Page
- Sort Options
Item Characterizing Region-Specific Glucose Metabolic Profile of the Rodent Brain Using Seahorse XFe96 Analyzer(2022) Wang, Linshu; Chaudhari, Kiran; Winters, Ali; Sun, Yuanhong; Liu, Ran; Yang, ShaohuaPurpose: The brain is highly complex with diverse structural characteristics in accordance with specific functions. Accordingly, differences in regional function, cellular compositions, and active metabolic pathways may link to differences in glucose metabolism at different brain regions. A recent study using imaging mass spectrometry demonstrated that some of the glucose metabolism enzymes and ATP level vary dramatically cross the brain. Disruption of glucose metabolism forms the pathophysiological basis for many brain disorders. Therefore, the brain spatial metabolic signatures are of high relevance in our understanding of the normal brain physiology and neuropathology of neurological diseases. Method: We optimized an acute biopsy punching method and characterized region-specific glucose metabolism of rat and mouse brain by a Seahorse XFe96 analyzer. Results: In the current study, we demonstrated that 0.5 mm diameter tissue punches from 180-µm thick brain sections allow metabolic measurements of anatomically defined brain structures using Seahorse XFe96 analyzer. We found that the cerebellum displays a more quiescent phenotype of glucose metabolism than cerebral cortex, basal ganglia, and hippocampus. In addition, the cerebellum has higher AMPK activation than other brain regions evidenced by the expression of pAMPK, upstream pLKB1, and downstream pACC. Furthermore, rodent brain has relatively low mitochondrial oxidative phosphorylation efficiency with up to 30% of respiration linked to proton leak. Conclusions: The present study determined the region-specific glucose metabolic profile of rodent brain using acute biopsy punches and Seahorse XFe96 analyzer. The metabolic flux analysis indicated that the cerebellum has a more quiescent phenotype of glucose metabolism as compared with the cerebrum. In addition, glucose metabolism might be less efficient in the brain than we expected, with relatively large component of proton leak-linked respiration.Item Determination of metformin bio-distribution by LC-MS/MS in mice treated with a clinically relevant paradigm(PLOS, 2020-06-11) Chaudhari, Kiran; Wang, Jianmei; Xu, Yong; Winters, Ali; Wang, Linshu; Dong, Xiaowei; Cheng, Eric Y.; Liu, Ran; Yang, ShaohuaMetformin, an anti-diabetes drug, has been recently emerging as a potential "anti-aging" intervention based on its reported beneficial actions against aging in preclinical studies. Nonetheless, very few metformin studies using mice have determined metformin concentrations and many effects of metformin have been observed in preclinical studies using doses/concentrations that were not relevant to therapeutic levels in human. We developed a liquid chromatography-tandem mass spectrometry protocol for metformin measurement in plasma, liver, brain, kidney, and muscle of mice. Young adult male and female C57BL/6 mice were voluntarily treated with metformin of 4 mg/ml in drinking water which translated to the maximum dose of 2.5 g/day in humans. A clinically relevant steady-state plasma metformin concentrations were achieved at 7 and 30 days after treatment in male and female mice. Metformin concentrations were slightly higher in muscle than in plasma, while, ~3 and 6-fold higher in the liver and kidney than in plasma, respectively. Low metformin concentration was found in the brain at ~20% of the plasma level. Furthermore, gender difference in steady-state metformin bio-distribution was observed. Our study established steady-state metformin levels in plasma, liver, muscle, kidney, and brain of normoglycemic mice treated with a clinically relevant dose, providing insight into future metformin preclinical studies for potential clinical translation.Item Metabolic Heterogeneity of Cerebral Cortical and Cerebellar Astrocytes(MDPI, 2023-01-22) Sun, Yuanhong; Winters, Ali; Wang, Linshu; Chaudhari, Kiran; Berry, Raymond; Tang, Christina; Liu, Ran; Yang, ShaohuaAstrocytes play critical roles in regulating neuronal synaptogenesis, maintaining blood-brain barrier integrity, and recycling neurotransmitters. Increasing numbers of studies have suggested astrocyte heterogeneity in morphology, gene profile, and function. However, metabolic phenotype of astrocytes in different brain regions have not been explored. In this paper, we investigated the metabolic signature of cortical and cerebellar astrocytes using primary astrocyte cultures. We observed that cortical astrocytes were larger than cerebellar astrocytes, whereas cerebellar astrocytes had more and longer processes than cortical astrocytes. Using a Seahorse extracellular flux analyzer, we demonstrated that cortical astrocytes had higher mitochondrial respiration and glycolysis than cerebellar astrocytes. Cerebellar astrocytes have lower spare capacity of mitochondrial respiration and glycolysis as compared with cortical astrocytes. Consistently, cortical astrocytes have higher mitochondrial oxidation and glycolysis-derived ATP content than cerebellar astrocytes. In addition, cerebellar astrocytes have a fuel preference for glutamine and fatty acid, whereas cortical astrocytes were more dependent on glucose to meet energy demands. Our study indicated that cortical and cerebellar astrocytes display distinct metabolic phenotypes. Future studies on astrocyte metabolic heterogeneity and brain function in aging and neurodegeneration may lead to better understanding of the role of astrocyte in brain aging and neurodegenerative disorders.Item Neural Cytoskeleton Modulation after Transient Ischemic Attack and Region-Specific Brain Metabolism Insights(2022-08) Wang, Linshu; Yang, Shaohua; Sumien, Nathalie; Schreihofer, Derek A.; Liu, RanTransient ischemic attack (TIA) is a symptomatic diagnosis disease characterized as reversible ischemic stroke-like neurological deficit. One-third of the TIA patients have recurrent episodes, and TIA presents as a high vascular risk factor for severe stroke, mild cognitive impairment, and dementia. However, the neuropathophysiology of TIA has been less studied. Here, we established recurrent TIA model in rats with no neurological deficits and no/minimal apoptosis cells detected. Our study demonstrated that recurrent TIA induces neuronal cytoskeleton modification, astrogliosis and microgliosis in the TIAaffected cortical and basal ganglia regions, as well as in the white matter in terms of corpus callosum in the acute and subacute stage. Our data indicate recurrent TIA-induced neuronal cytoskeletal modification and neuroinflammation, may be potentially involved in the vascular contribution to cognitive impairment and dementia. Even though neurological deficits are transient in TIA patients, the brain presents morphologic and metabolic change in response to transient ischemic insult. This can be reflected on the remodeling of cytoskeleton, which plays a critical role in the mitochondria shape and motility maintenance. In addition, the interaction between cytoskeletal components and mitochondria is highly involved in the oxidative phosphorylation and mitochondrial respiration regulation. To investigate the brain metabolic signatures in the normal and pathological conditions, our study optimized a method that enables metabolic function assessment of anatomically defined brain structures by the Seahorse XFe96 analyzer in rodents. Our data demonstrated that the rodent brain has region-specific glucose metabolic profile, the cerebellum displays a more quiescent phenotype than cerebral cortex, basal ganglia, and hippocampus. Additionally, the rodent brain has relatively low mitochondrial oxidative phosphorylation efficiency with high proton leaklinked respiration. Through our proof-of-principle study, we expect to acquire critical insights that will enable future research in pursuit of spatial mapping of the brain glucose metabolism in physiological and pathological conditions (e.g., TIA condition), and further explore the mechanisms and significance of mitochondrial uncoupling of the brain.