Effects of vascular endothelial growth factor (VEGF) on motor neuron degeneration.

Both in mice and humans, low expression levels of vascular endothelial growth factor (VEGF) are linked to adult-onset motor neuron disease or amyotrophic lateral sclerosis (ALS). The mechanism through which reduced VEGF levels result in this phenotype is unknown. We therefore examined the direct effects of VEGF on motor neurons and found VEGF to have a direct neurotrophic effect on motor neurons in vitro.

Upregulation of HSP27 in a transgenic model of ALS.

Mutations of the SOD1 gene underlie 1 form of familial amyotrophic lateral sclerosis (ALS). Their pathogenic mechanism remains uncertain, but is thought to involve oxidative stress and abnormal protein aggregation, 2 processes known to induce heat shock proteins (HSPs). We studied the expression of 3 HSPs (alphaB-crystallin, HSP27, and HSP70) in transgenic mice overexpressing human mutant (G93A and G37R) SOD1, using a combination of immunohistochemistry and immunoblotting.

An alpha-mercaptoacrylic acid derivative (PD150606) inhibits selective motor neuron death via inhibition of kainate-induced Ca2+ influx and not via calpain inhibition.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by selective motor neuron death. The exact mechanism responsible for this selectivity is not clear, although it is known that motor neurons are very sensitive to excitotoxicity. This high sensitivity is due to a high density of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors on their surface and to a limited Ca(2+) buffering capacity.

Protective effect of parvalbumin on excitotoxic motor neuron death.

The mechanism responsible for the selective vulnerability of motor neurons in amyotrophic lateral sclerosis (ALS) is poorly understood. Several lines of evidence indicate that susceptibility of motor neurons to Ca(2+) overload induced by excitotoxic stimuli is involved. In this study, we investigated whether the high density of Ca(2+)-permeable AMPA receptors on motor neurons gives rise to higher Ca(2+) transients in motor neurons compared to dorsal horn neurons.

Deletion of the hypoxia-response element in the vascular endothelial growth factor promoter causes motor neuron degeneration.

Hypoxia stimulates angiogenesis through the binding of hypoxia-inducible factors to the hypoxia-response element in the vascular endothelial growth factor (Vegf) promotor. Here, we report that deletion of the hypoxia-response element in the Vegf promotor reduced hypoxic Vegf expression in the spinal cord and caused adult-onset progressive motor neuron degeneration, reminiscent of amyotrophic lateral sclerosis. The neurodegeneration seemed to be due to reduced neural vascular perfusion.