Deoxyglucose uptake by mouse astrocytes: effects of temperature and retrovirus infection
J M Vann1, A J Goldman, P F Szurek
1Neurology Service, William S. Middleton Memorial Veterans Hospital, Madison, WI 53705-2286, USA.
Abstract:
Deoxyglucose uptake by FVB/N mouse astrocytes was studied before and after infection by ts1 retrovirus which causes a neurodegenerative disease in mice similar to HIV-1 encephalopathy in man. The Michaelis-Menten kinetic parameters, Km and Vmax, of 2-deoxy-D-glucose uptake by brain and cerebellar astrocytes were measured following culture at 34 degrees C where ts1 retrovirus replicates optimally, and at 37 degrees C. Compared to astrocytes cultured at 37 degrees C, astrocytes cultured at 34 degrees C had increased Km and decreased deoxyglucose uptake despite increased or unchanged Vmax. Following ts1 retrovirus infection, brain astrocyte deoxyglucose uptake doubled [132%] associated with decreased Km but unchanged Vmax, whereas cerebellar astrocyte deoxyglucose uptake doubled [102%] associated with increased Vmax but unchanged Km. These observations of altered deoxyglucose uptake kinetic parameters following retrovirus infection indicate different neurochemical mechanisms for the regional variation in deoxyglucose uptake observed following retrovirus infection of the CNS in vivo.
Insights
Retrovirus infection alters astrocyte glucose metabolism differently in the brain and cerebellum. This study reveals key changes in Michaelis-Menten kinetic parameters for deoxyglucose uptake, impacting neurochemical mechanisms in neurodegenerative disease.
Area of Science:
- Neuroscience
- Cellular Metabolism
- Virology
Background:
- Neurodegenerative diseases, such as HIV-1 encephalopathy, involve central nervous system (CNS) dysfunction.
- Astrocytes play a critical role in brain energy metabolism and are affected during CNS infections.
- Retroviral infections can lead to significant alterations in neuronal and glial cell function.
Purpose of the Study:
- To investigate the impact of ts1 retrovirus infection on 2-deoxy-D-glucose uptake in FVB/N mouse astrocytes.
- To determine the Michaelis-Menten kinetic parameters (Km and Vmax) of glucose uptake in astrocytes under different temperature conditions and post-infection.
- To explore regional differences in astrocyte glucose metabolism following retroviral infection.
Main Methods:
- Primary astrocyte cultures from FVB/N mouse brains and cerebellums were established.
- Cells were cultured at permissive (34°C) and non-permissive (37°C) temperatures for ts1 retrovirus replication.
- 2-deoxy-D-glucose uptake assays were performed to measure Michaelis-Menten kinetic parameters (Km and Vmax) before and after retrovirus infection.
Main Results:
- Astrocytes cultured at 34°C showed increased Km and decreased deoxyglucose uptake compared to those at 37°C, despite unchanged or increased Vmax.
- Following ts1 retrovirus infection, brain astrocytes exhibited a 132% increase in deoxyglucose uptake with decreased Km and unchanged Vmax.
- Cerebellar astrocytes showed a 102% increase in deoxyglucose uptake with increased Vmax and unchanged Km post-infection.
Conclusions:
- Ts1 retrovirus infection significantly alters astrocyte glucose uptake kinetics in a region-specific manner.
- The observed changes in Km and Vmax suggest distinct neurochemical adaptations in brain versus cerebellar astrocytes.
- These findings highlight differential metabolic responses in astrocytes that may contribute to the regional variations in CNS pathology during retroviral infections.
