Degenerative or Debilitative Neurologic Syndromes

Notopterol inhibits LPS-induced inflammation in BV-2 cells via AKT/Nrf2/HO-1 signaling axis

Accumulating research has indicated that inordinate activation of microglia releases inflammatory cytokines, damages neurons, and causes neuroinflammation, which eventually could lead to neurodegenerative diseases such as Parkinson's disease and Huntington's disease, etc. Notopterol (NOT) has anti-inflammatory and anti-oxidant functions in boundary tissues, but the effects of NOT on neuroinflammation have not been covered. Therefore, this study attempts to investigate the effect of NOT on neuroinflammation and the underlying mechanisms. According to the findings, NOT dramatically decreased the expression of pro-inflammatory mediators (interleukin-6 (IL-6), inducible nitric-oxide synthase (iNOS), tumor necrosis factor-α (TNF-α), and Cyclooxygenase-2 (COX-2)) in LPS-exposed BV-2 cells. Western blot analysis revealed that NOT could promote the activation of AKT/Nrf2/HO-1 signaling pathway. Further studies have shown that anti-inflammatory property of NOT was inhibited by MK2206 (an AKT inhibitor), RA (an Nrf2 inhibitor), and SnPP IX (an HO-1 inhibitor). In addition, it was also discovered that NOT could weaken the damage of LPS to BV-2 cells and improve their survival rate. As a result, our results imply that NOT inhibits the inflammatory response of BV-2 cells through the AKT/Nrf2/HO-1 signaling axis and exerts a neuroprotective effect by inhibiting the activation of BV-2 cells.

The Role of NADPH Oxidases and Oxidative Stress in Neurodegenerative Disorders

For a number of years, nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOX) was synonymous with NOX2/gp91^phox and was considered to be a peculiarity of professional phagocytic cells. Over the last decade, several more homologs have been identified and based on current research, the NOX family consists of NOX1, NOX2, NOX3, NOX4, NOX5, DUOX1 and DUOX2 enzymes. NOXs are electron transporting membrane proteins that are responsible for reactive oxygen species (ROS) generation-primarily superoxide anion (O₂^●-), although hydrogen peroxide (H₂O₂) can also be generated. Elevated ROS leads to oxidative stress (OS), which has been associated with a myriad of inflammatory and degenerative pathologies. Interestingly, OS is also the commonality in the pathophysiology of neurodegenerative disorders, such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS). NOX enzymes are expressed in neurons, glial cells and cerebrovascular endothelial cells. NOX-mediated OS is identified as one of the main causes of cerebrovascular damage in neurodegenerative diseases. In this review, we will discuss recent developments in our understanding of the mechanisms linking NOX activity, OS and neurodegenerative diseases, with particular focus on the neurovascular component of these conditions. We conclude highlighting current challenges and future opportunities to combat age-related neurodegenerative disorders by targeting NOXs.