Chromogranin peptides in amyotrophic lateral sclerosis

Area of Science:

• Neuroscience
• Cell Biology

Background:

• Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease impacting motor neurons.
• Vesicular proteins play crucial roles in neuronal function and communication.

Purpose of the Study:

• To investigate the expression and localization of specific vesicular proteins, including chromogranins and synaptophysin, in the motor neurons of ALS patients.
• To explore the potential co-localization of superoxide dismutase 1 (SOD1) with these vesicular proteins in ALS.

Main Methods:

• Semiquantitative immunocytochemistry was employed to analyze motor neurons from eight ALS cases and seven controls.
• Specific antibodies were used to detect chromogranin A, chromogranin B, secretogranin II, synaptophysin, and SOD1.
• Confocal microscopy was utilized to examine the subcellular localization of proteins within motor neurons.

Main Results:

• A significant reduction in chromogranin peptides and synaptophysin staining intensity was observed in the ventral horn of ALS patients, correlating with motor neuron loss.
• Remaining motor neurons in ALS patients showed intracellular accumulation of chromogranins.
• Superoxide dismutase 1-immunopositive aggregates within motor neurons contained chromogranin A, B, and secretogranin II.

Conclusions:

• The findings suggest a loss of both small and large dense core vesicles in presynaptic terminals of ALS motor neurons.
• The intracellular co-occurrence of SOD1 and chromogranins indicates a potential functional interaction, warranting further investigation into their roles in ALS pathogenesis.