Traumatic brain injury (TBI) is a leading cause of morbidity and mortality worldwide. Due to its high incidence rate and often long-term sequelae, TBI contributes significantly to increasing costs of health care expenditures annually. Unfortunately, advances in the field have been stifled by patient and injury heterogeneity that pose a major challenge in TBI prevention, diagnosis, and treatment. In this review, we briefly discuss the causes of TBI, followed by its prevalence, classification, and pathophysiology. The current imaging detection methods and animal models used to study brain injury are examined. We discuss the potential use of molecular markers in detecting and monitoring the progression of TBI, with particular emphasis on microRNAs as a novel class of molecular modulators of injury and its repair in the neural tissue.

No abstract

One of the hallmarks of Alzheimer's disease (AD) is the accumulation and deposition of amyloid-β (Aβ) peptides in the brain and cerebral vasculature. Aβ evokes neuroinflammation and has been implicated in insulin signaling disruption and JNK-AP1 activation, contributing to AD neuropathologies including oxidative injury and vascular insufficiencies. In this study we aim to better understand the protective mechanisms of insulin signaling and JNK-AP1 inhibition on the adverse effects of Aβ. Four-hour treatment of hCMEC/D3, the immortalized human brain endothelial cells (iHBEC), with Aβ1-42 resulted in significant c-Jun phosphorylation, oxidative stress, and cell toxicity. Concurrent treatment with Aβ1-42 and insulin or Aβ1-42 and JNK inhibitor SP600125 significantly improved cell viability. Cytokine array on conditioned media showed that insulin and SP600125 strongly reduced all Aβ1-42-induced cytokines. ELISA confirmed the protective effect of insulin and SP600125 on Aβ-induced expression of interleukin (IL)-8 and Growth related oncogene-α (Gro-α). qRT-PCR revealed that insulin and SP600125 protected iHBEC from Aβ1-42-induced inflammatory gene expression. Transcription factor profiling showed that treatment of iHBEC with Aβ1-42, insulin, or SP600125 alone or in combination resulted in profound changes in modulating the activities of multiple transcription factors and relevant pathways, some of which were validated by western blot. Insulin treatment and JNK inhibition in vitro synergistically reduced c-Jun phosphorylation and thus JNK-AP1 signaling activation. The study suggests that activation of insulin and blocking of JNK-AP1 signaling inhibits Aβ-induced dysregulation of insulin signaling and inflammatory response.

Alzheimer's disease (AD) is characterized by amyloid-b (Ab) toxicity, tau pathology, insulin resistance, neuroinflammation, and dysregulation of cholesterol homeostasis, all of which play roles in neurodegeneration.