The Effect of Celecoxib on Neuroinflammation in MDD

Major depressive disorder (MDD) affects an estimated 350 million people worldwide and is a leading contributor to global disease burden. Commonly used monoamine reuptake-inhibiting treatments for depression are suboptimal, resulting in only 30% of patients achieving remission. This may be because monoamine dysfunction is not the primary pathophysiology in all MDD patients. One avenue for the development of novel MDD treatments is through anti-inflammatory drugs; MDD is linked to a pro-inflammatory phenotype characterized by microglial activation, leading to the release of pro-inflammatory cytokines and upregulation of cellular markers including cyclooxygenase-2 (COX-2) and translocator protein (TSPO; a protein located on the outer membrane of microglia). Relevant to this proposal, TSPO can serve as an in vivo marker of neuroinflammation using the newly developed positron emission tomography (PET) tracer for TSPO, \[18F\]FEPPA. In support of this, a recent \[18F\]FEPPA PET study found that MDD patients in a current major depressive episode (MDE) had significantly higher TSPO binding in the prefrontal cortex (PFC), anterior cingulate cortex (ACC) and insula, relative to healthy controls. The prefrontal cortex and ACC are both implicated in mood regulation whereas the insula is involved in interoceptive signaling, which is known to be abnormal in MDD. Celecoxib, a selective COX-2 nonsteroidal anti-inflammatory drug (NSAID), is a promising new treatment for neuroinflammation in MDD. Clinical studies have observed that, in a subset of depressed patients, celecoxib treatment reduced depression severity as assessed by the Hamilton Depression Rating Scale (HDRS). While these findings demonstrate that celecoxib reduces symptom severity, PET imaging technology is critical for understanding how celecoxib affects the underlying pathophysiology of depression. Here, the team will investigate neuroinflammation as an underlying pathology in depression and test whether neuroinflamma