Selective overexpression of γ1 laminin in astrocytes in amyotrophic lateral sclerosis indicates an involvement in ALS pathology

Our earlier studies indicate that the KDI tripeptide of gamma 1 laminin reverts paralysis and protects adult rat CNS from excitotoxicity of glutamate and from oxidative stress. Here we show that gamma 1 laminin is selectively overexpressed in reactive astrocytes of the amyotrophic lateral sclerosis (ALS) spinal cord, with both gray and white matter astrocytes overexpressing gamma 1 laminin. Intensely gamma 1 laminin-positive, aggressive-looking reactive astrocytes of the lateral columns of both cervical and thoracic spinal cord surround the lateral ventral horns and roots and extend into the area of the lateral corticospinal tract. In the cervical ALS spinal cord, large numbers of strongly gamma 1 laminin-immunoreactive astrocytes are also present in the dorsal columns of the ascending sensory pathways. No other laminin or any other ALS-associated protein localizes in this manner. This unique distribution of gamma 1 laminin-immunoreactive astrocytes in the ALS white matter together with our recent results on the efficacy of the KDI domain as a neuronal protector strongly suggest that gamma 1 laminin may be expressed by astrocytes of the ALS spinal cord as a protective measure intended to aid neuronal survival. Further comparative studies on ALS spinal cord tissues and those of the animal models of ALS are needed to clarify the specific role of gamma 1 laminin and its KDI domain in ALS and its putative interactions with the additional ALS-associated factors, such as excitotoxicity, oxidative stress, and neurofilament accumulation. Most importantly, further studies are urgently needed to test the potential of the KDI tripeptide as a therapeutic treatment for ALS. (c) 2007 Wliey-Liss, Inc.