White matter damage after traumatic brain injury: A role for damage associated molecular patterns

• Published in: Biochimica et biophysica acta Vol. 1863; no. 10; pp. 2614 - 2626
• Main Authors: Braun, Molly, Vaibhav, Kumar, Saad, Nancy M., Fatima, Sumbul, Vender, John R., Baban, Babak, Hoda, Md Nasrul, Dhandapani, Krishnan M.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.10.2017
• Subjects: Adenosine Triphosphate - immunology; Adenosine Triphosphate - metabolism; Animals; Brain Injuries, Traumatic - immunology; Brain Injuries, Traumatic - metabolism; Brain Injuries, Traumatic - pathology; Brain Injuries, Traumatic - therapy; HMGB1; HMGB1 Protein - immunology; HMGB1 Protein - metabolism; Humans; Hyaluronic Acid - immunology; Hyaluronic Acid - metabolism; Leukocyte; Lymphocyte; Macrophage; Macrophages - immunology; Macrophages - metabolism; Macrophages - pathology; Microglia; Oligodendrocyte; Receptors, Pattern Recognition - immunology; Receptors, Pattern Recognition - metabolism; S100; S100 Proteins - immunology; S100 Proteins - metabolism; T-cell; Toll like receptor; White Matter - immunology; White Matter - metabolism; White Matter - pathology; White matter injury; Oligodendrocyte; T-cell; Leukocyte; S100; Toll like receptor; White matter injury; HMGB1; Lymphocyte; Microglia; Macrophage
• ISSN: 0925-4439; 0006-3002; 1879-260X; 1878-2434
• DOI: 10.1016/j.bbadis.2017.05.020

Traumatic brain injury (TBI) is a leading cause of mortality and long-term morbidity worldwide. Despite decades of pre-clinical investigation, therapeutic strategies focused on acute neuroprotection failed to improve TBI outcomes. This lack of translational success has necessitated a reassessment of the optimal targets for intervention, including a heightened focus on secondary injury mechanisms. Chronic immune activation correlates with progressive neurodegeneration for decades after TBI; however, significant challenges remain in functionally and mechanistically defining immune activation after TBI. In this review, we explore the burgeoning evidence implicating the acute release of damage associated molecular patterns (DAMPs), such as adenosine 5′-triphosphate (ATP), high mobility group box protein 1 (HMGB1), S100 proteins, and hyaluronic acid in the initiation of progressive neurological injury, including white matter loss after TBI. The role that pattern recognition receptors, including toll-like receptor and purinergic receptors, play in progressive neurological injury after TBI is detailed. Finally, we provide support for the notion that resident and infiltrating macrophages are critical cellular targets linking acute DAMP release with adaptive immune responses and chronic injury after TBI. The therapeutic potential of targeting DAMPs and barriers to clinical translational, in the context of TBI patient management, are discussed. •White matter injury induces long-term neurological disability after TBI.•Acute release of DAMPs activates myeloid cells after TBI.•DAMP-induced myeloid cell activation initiates adaptive immunity after TBI.•We provide a mechanistic framework for immune targeting to improve TBI outcomes.