Innate immunity: the missing link in neuroprotection and neurodegeneration?

Abstract

Innate immunity was previously thought to be a nonspecific immunological programme that was engaged by peripheral organs to maintain homeostasis after stress and injury. Emerging evidence indicates that this highly organized response also takes place in the central nervous system. Through the recognition of neuronal fingerprints, the long-term induction of the innate immune response and its transition to an adaptive form might be central to the pathophysiology and aetiology of neurodegenerative disorders. Paradoxically, this response also protects neurons by favouring remyelination and trophic support afforded by glial cells.

Inflammation and epilepsy

“…This phenomenon comprises an early inflammatory response (innate immunity) which can eventually progress to an adaptive immune response, mediated by activated lymphocytes recruited from the blood (11). The CNS shows a well-organized innate immune reaction in response, not only to systemic or intracerebral bacterial infection, but also to a variety of brain injuries.…”

Inflammation and spinal cord injury: Infiltrating leukocytes as determinants of injury and repair processes

“…However, we now know that the CNS, when challenged by injury and systemic infections, has the ability to mount a wellorganized immune response (2) . Evidence over the past two decades has thus redefined the Brain versus spinal cord-Injury to the spinal cord results in a more robust inflammatory response than seen in the brain (7,8) .…”

“…These receptors, expressed at the surface of antigen presenting cells, bind to specific components of the pathogen, the pathogenassociated molecular patterns, which in turn leads to activation of antigen presenting cells (2) . Once antigen presenting cells are activated they phagocytose debris, express major histocompatibility complex II (MHC II) molecules on their surface, and present peptides that have been degraded to helper T-lymphocytes.…”

Neuroprotective roles of the P2Y2 receptor

“…Inflammation is an early response to injury, although it remains controversial whether the inflammatory response is beneficial or detrimental to brain tissue [194,195]. Chronic inflammation damages cells and is thought to be a key player in neurodegenerative disorders, such as AD [193].…”