Neuroinflammation, COX-2, and ALS--a dual role?

Although the root cause of many neurodegenerative diseases is unknown, neuroinflammation may play a key role in these types of disease, including amyotrophic lateral sclerosis (ALS). In the context of neurodegeneration, it is unclear if the disease is propagated through inflammation, or whether in contrast, evidence of inflammation reflects an attempt to protect against further cellular injury. Inflammatory pathways involving the cyclooxygenase (COX) enzymes and subsequent generation of prostaglandins are potential target sites for treatments to halt the progression of ALS. In the CNS, COX enzymes are localized to neurons, astrocytes, and microglia and can be induced under various conditions. In addition, there appears to be a dual role for the prostaglandin products of COX enzymes in the nervous system. Some prostaglandins promote the survival of neurons, while others promote apoptosis. In this review, the pathways of COX activity and prostaglandin production form the center of the debate regarding the dual nature of neuroinflammation. We will also discuss how this duality may affect future treatments for neurodegenerative diseases such as ALS.