Figure 1.
Site of action of dichloroacetate.
DCA inhibits the mitochondrial enzyme PDH kinase, thereby maintaining the PDH complex in its unphosphorylated catalytically active state and facilitating the aerobic oxidation of glucose.
Figure 2.
DCA recovers mitochondrial respiration rate and controls proliferation in SOD1G93A astrocytes.
A) Representative immunoblot for PDH-E1α(pSer293), total PDH-E1α, and β-actin of lysates from non Tg and SOD1G93A astrocytes after 24 h treatment with DCA or vehicle as described in Methods. B) Quantification of the PDH-E1α(pSer293) to total PDH-E1α ratio between relative densitometric levels normalized against vehicle-treated non Tg astrocytes. C) Calculated respiratory control ratio (RCR) for mitochondria from non Tg or SOD1G93A-bearing astrocytes treated with DCA or vehicle as indicated. D) Percentage of BrdU immunoreactive nuclei of non Tg and SOD1G93A astrocytes after 24 h treatment with DCA. Data for panels B, C, and D are expressed as mean ± SEM from three independent experiments performed in duplicate. *p<0.05, significantly different from non Tg control. **p<0.05, significantly different from SOD1G93A control.
Figure 3.
DCA prevents SOD1G93A astrocyte neurotoxicity to motor neurons.
Motor neuron survival 72 h after plating either on non Tg or SOD1G93A-bearing astrocytes pretreated with DCA or vehicle as indicated. Data are expressed as percentage of non Tg control, mean ± SEM from four independent experiments. *p<0.05, significantly different from non Tg control. **p<0.05, significantly different from SOD1G93A control.
Figure 4.
DCA increases mean survival of SOD1G93A transgenic mice.
Kaplan-Meyer survival curves from DCA-treated and control SOD1G93A male (A) and female (B) mice. DCA was administered in drinking water from 70 days of age until death as detailed in materials and methods. 9 animals per group, p<0.05, Kaplan-Meyer log-rank test.
Figure 5.
DCA delays loss of grip strength and neuromuscular junction shrinkage in SOD1G93A mice.
A) Hind-limb grip strength records from non Tg or SOD1G93A male mice treated with DCA or vehicle as indicated. DCA-treated non Tg animals did not show differences with control ones and data are not shown in order to simplify the graph. Data are mean ± SEM from 9 animals per group. *p<0.05, significantly different from SOD1G93A control. B) ACh receptors labeled with TMR-BgTx in representative EDL neuromuscular junctions from non Tg (top), SOD1G93A control (middle) or DCA-treated SOD1G93A (bottom). Quantification of total TMR-BgTx-stained neuromuscular area in the different groups of animals. Data are expressed as percentage of non Tg control, mean ± SEM from 15–35 neuromuscular junctions from 2–4 animals per group. *p<0.05, significantly different from non Tg control. **p<0.05, significantly different from SOD1G93A control. Scale bar: 30 µm.
Figure 6.
DCA improves mitochondrial function in the spinal cord of SOD1G93A mice.
Calculated respiratory control ratio (RCR) for spinal cord mitochondria from non Tg or SOD1G93A mice treated with DCA or vehicle as indicated. Data are mean ± SEM from three independent experiments. *p<0.05, significantly different from non Tg control. **p<0.05, significantly different from SOD1G93A control.
Figure 7.
DCA reduces motor neuron loss and astrocyte reactivity in the spinal cord of SOD1G93A mice.
Representative Toluidine blue stain (left column) and GFAP immunofluorescence (red, right column) in anterior horn spinal cord sections from non Tg (top), SOD1G93A control (middle) or DCA-treated SOD1G93A (bottom) mice. Dotted lines in right column panels indicate the limit between grey and white matter. The graphs indicate the number of neuronal somas located in Rexed lamina IX (left) and the percentage of GFAP immunoreactive area in the ventral horn (right) in the indicated groups of animals. The corresponding measurement areas are drawn in the top. Data are mean ± SEM from at least three animals per group as indicated in Methods. *p<0.05, significantly different from non Tg control, **p<0.05, significantly different from SOD1G93A control. Scale bars: 50 µm.