Multiple sclerosis (MS) is a chronic human demyelinating disorder of the CNS having an autoimmune connection. At present, about 400,000 people in the United States have MS. It is more common among Caucasians, particularly those of northern European ancestry. Several evidences show a potential link between the incidence of MS and combat service. For example, one study in the Annals of Neurology (2004, 55: 65-71) has identified 5,345 cases of MS among U.S. veterans that were deemed service-connected. Although the mechanism is not clear, viral infections, several vaccinations and exposure to different war zone chemicals may increase the risk of having MS. Accordingly, several veterans who served Gulf war 1 as well as many Vietnam veterans have been diagnosed with MS. In spite of extensive research, no effective therapy is available to halt the progression of MS. Inflammation and demyelination are major pathological features of MS and experimental allergic encephalomyelitis (EAE), an animal model of MS. Therefore, suppressing inflammation and promoting remyelination, appear to be crucial therapeutic challenges for MS. While neurotrophins (NGF, NT-3, NT-4/5, and BDNF) and glial cell line-derived neurotrophic factor (GDNF)-related factors (GDNF, neurturin) do not increase myelinogenesis, ciliary neurotrophic factor (CNTF) induces a strong promyelinating effect. Therefore, increasing the level of CNTF in the CNS is an important step in repairing axonal damage in MS. Although gene manipulation and stereotaxic injection of CNTF into the brain are available options, it seems from the therapeutic angle, the best option is to stimulate/induce the production of CNTF within the CNS of patients with MS. Is it really possible? Our preliminary results show that it is possible with aspirin, acetylsalicylic acid, one f the most widely-used analgesics throughout the world. We have discovered that aspirin increases myelinogenic trophic factor CNTF and upregulates anti-inflammatory molecules in astrocytes via involving different peroxisome proliferator-activated receptors (PPARs). Furthermore, oral administration of aspirin reduces clinical symptoms of EAE. This grant is anchored to these exciting findings. From the academic angle, we have dedicated Specific aims I and II to investigate molecular mechanisms behind these novel trophic and anti-inflammatory efficacies of aspirin. From the therapeutic angle, we will test the effect of aspirin on myelinatio and anti-inflammation and the overall disease process of relapsing-remitting, chronic and spontaneous EAE in mice under Specific aim III. A positive outcome will highlight undiscovered properties of aspirin and enhance the possibility of controlling MS by this widely-used drug.