Possible role of apolipoprotein A1 in healing and cell death after neuronal injury.

Limited axonal regeneration after traumatic injuries to the CNS presents a challenge in neuroscience. Investigation of CSF from subjects with spinal cord injury (SCI) has found that the lipid catabolism pathway is implicated in the post injury scenario. Sequestration of the CNS by the blood brain barrier ensures a mechanism of cholesterol metabolism and recycling distinct from that in the peripheral tissues. Apolipoprotein A1, the protein component of high density lipoprotein (HDL), is an abundant protein in the mammalian cerebrospinal fluid. Interaction of ApoA1 with its cellular receptor, ABCA1, gives rise to several signaling events, such as the activation of Cdc42 protein leading to actin polymerisation. Emerging evidences suggest that ApoA1 mediates anti-inflammatory effects and conversely, is negatively regulated by inflammatory cytokines. Collating these findings, added to the clinical evidences of using HDL as a therapeutic target for cardio vascular diseases, we hypothesize that ApoA1 could be useful in neurite outgrowth after mechanical injury by 1) mediating polymerisation of actin and 2) restricting inflammatory responses after injury which are deleterious to healing.