ALS, short for Amyotrophic lateral sclerosis, is a degenerative disease that attacks nerve cells in the brain and spinal cord, leading to a loss of muscle control. Initial symptoms include muscle twitching, limb weakness, and slurred speech, which eventually progress to impaired control of vital functions such as movement, speech, eating, and breathing.

Currently, there is no cure for this fatal condition. Typically, doctors are unsure of the cause of ALS. Some illnesses run in families.

A new study provides fresh insights into the biology of spinal cord cells that deteriorate in ALS and other neurological disorders.

The National Institutes of Health-funded research team has discovered evidence linking the genes that underlie motor neurons’ susceptibility to degeneration in ALS with their large cell size and supporting structure. Results were published in Neuron.

The research produced a catalog (or “atlas”) describing the vast variety of cell types found in the human spinal cord.

By looking at gene expression in a single cell, the researchers were able to find and study dozens of different cell types in the spinal cord.

They proved the use of the atlas by examining motor neurons, which are responsible for voluntary movement and motor control.

Motor neurons, which deteriorate and die in ALS, are big cells with one long extension called an axon that transports messages from the spinal cord to the muscle fiber and is up to one meter in length.

The researchers discovered that motor neurons are differentiated by a group of genes that not only allow for the enormous size of the motor neuron cell body and the length of the axon, but also contribute to their sensitivity to degeneration.

Cytoskeletal genes (responsible for the shape and function of cells) and neurofilament genes (responsible for the size of cells) as well as ALS susceptibility genes defined their molecular profile.

More tests showed that ALS-related genes are also more common in mice motor neurons.

The findings shed light on amyotrophic lateral sclerosis (ALS) and prove the value of the spinal cell atlas in the research of disease and the development of therapies.

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