Hyperglycemia Alters Astrocyte Metabolism and Inhibits Astrocyte Proliferation.

Wenjun Li,Jude Prah,Gourav Roy Choudhury,Ali Winters,Wenping Lin,Shao-Hua Yang,Ran Liu

doi:10.14336/ad.2017.1208

Abstract

Diabetes milieu is a complex metabolic disease that has been known to associate with high risk of various neurological disorders. Hyperglycemia in diabetes could dramatically increase neuronal glucose levels which leads to neuronal damage, a phenomenon referred to as glucose neurotoxicity. On the other hand, the impact of hyperglycemia on astrocytes has been less explored. Astrocytes play important roles in brain energy metabolism through neuron-astrocyte coupling. As the component of blood brain barrier, glucose might be primarily transported into astrocytes, hence, impose direct impact on astrocyte metabolism and function. In the present study, we determined the effect of high glucose on the energy metabolism and function of primary astrocytes. Hyperglycemia level glucose (25 mM) induced cell cycle arrest and inhibited proliferation and migration of primary astrocytes. Consistently, high glucose decreased cyclin D1 and D3 expression. High glucose enhanced glycolytic metabolism, increased ATP and glycogen content in primary astrocytes. In addition, high glucose activated AMP-activated protein kinase (AMPK) signaling pathway in astrocytes. In summary, our in vitro study indicated that hyperglycemia might impact astrocyte energy metabolism and function phenotype. Our study provides a potential mechanism which may underlie the diabetic cerebral neuropathy and warrant further in vivo study to determine the effect of hyperglycemia on astrocyte metabolism and function.

Highlights

Diabetes milieu is a complex metabolic disease that has been known to associate with high risk of various neurological disorders
Primary astrocytes were maintained in Dulbecco's Modified Eagle Medium (DMEM) media (10% mM glucose proliferated significantly slower than Fetal Bovine Serum (FBS)) with 5.5, 11 or 25 mM glucose for a week, and cells astrocytes cultured in 5.5 and 11 mM glucose (Fig. 1A). were split and cultured for 3-5 days before seeding There was no significant difference in the growth rates of astrocytes cultured 5.5 and 11 mM glucose
Mammalian brain is characterized by high metabolism of glucose which is transported into the brain through insulin-independent glucose transporter protein 1 and 3 (GLUT-1 and GLUT-3)

Summary

MATERIALS AND METHODS

Primary astrocytes were prepared according to previous study with modifications [23, 24]. Medium was removed, and cells were split into new plates and culture for 2-7 days. These cells were seeded and used for experiments. Astrocyte were seeded into 12-well (40,000 per well) or 24-well (25,000 per well) culture plates in DMEM with pyruvate and 10% FBS. Cells were cultured for two days, and medium was replaced with new normal glucose (5.5 mM) or high glucose (25 mM) DMEM (with pyruvate and 10% FBS). The astrocytes (2.5 × 105 cells/well) were cultured in normal glucose (5.5 mM) and high glucose (25 mM) DMEM (10% FBS) to a monoconfluent layer in 6-well cell culture plates. P < 0.05 (*) was considered significant

RESULTS

Findings

DISCUSSION