Melatonin against acute ischaemic stroke dependently via suppressing both inflammatory and oxidative stress downstream signallings
JOURNAL OF CELLULAR AND MOLECULAR MEDICINE
Authors: Chen, Kuan-Hung; Lin, Kun-Chen; Ko, Sheung-Fat; Chiang, John Y.; Guo, Jun; Yip, Ho-Kan
Abstract
This study tested the hypothesis that melatonin (Mel) therapy preserved the brain architectural and functional integrity against ischaemic stroke (IS) dependently through suppressing the inflammatory/oxidative stress downstream signalling pathways. Adult male B6 (n = 6 per each B6 group) and TLR4 knockout (ie TLR4(-/-)) (n = 6 per each TLR4(-/-)group) mice were categorized into sham control (SCB6), SCTLR4-/-, ISB6, ISTLR4-/-, ISB6 + Mel (i.p. daily administration) and ISTLR4-/-+ Mel (i.p. daily administration). By day 28 after IS, the protein expressions of inflammatory (HMBG1/TLR2/TLR4/MAL/MyD88/RAM TRIF/TRAF6/IKK-alpha/p-NF-kappa B/nuclear-NF-kappa B/nuclear-IRF-3&7/IL-1 beta/IL-6/TNF-alpha/IFN-gamma) and oxidative stress (NOX-1/NOX-2/ASK1/p-MKK4&7/p-JNK/p-c-JUN) downstream pathways as well as mitochondrial-damaged markers (cytosolic cytochrome C/cyclophilin D/SRP1/autophagy) were highest in group ISB6, lowest in groups SC(B6)and SCTLR4-/-, lower in group ISTLR4-/-+ Mel than in groups IS(TLR4-/-)and ISB6 + Mel and lower in group ISB6 + Mel than in group ISTLR4-/-(allP < .0001). The brain infarct volume, brain infarct area and the number of inflammatory cells in brain (CD14/F4-88) and in circulation (MPO+//Ly6C+/CD11b+//Ly6G+/CD11b+) exhibited an identical pattern, whereas the neurological function displayed an opposite pattern of inflammatory protein expression among the six groups (allP < .0001). In conclusion, TLR inflammatory and oxidative stress signallings played crucial roles for brain damage and impaired neurological function after IS that were significantly reversed by Mel therapy.
Vitamin D Induces Differential Effects on Inflammatory Responses During Bacterial and/or Viral Stimulation of Human Peripheral Blood Mononuclear Cells
FRONTIERS IN IMMUNOLOGY
Authors: Anderson, Jeremy; Do, Lien Anh Ha; Toh, Zheng Quan; Hoe, Edwin; Reitsma, Andrea; Mulholland, Kim; Licciardi, Paul V.
Abstract
Streptococcus pneumoniae (pneumococcus) and respiratory syncytial virus (RSV) are the leading causes of respiratory infections amongst children <5 years of age. Co-infection with these pathogens is common during early life and often associated with increased disease severity. Epidemiological studies have shown that low levels of Vitamin D-3 (VitD(3)) are associated with increased susceptibility to respiratory pathogens. However, the role of VitD(3) in the context of pneumococcal and RSV exposure are poorly understood. We found that VitD(3) significantly reduced Th17 cell expression and IL-17A and IL-22 secretion in peripheral blood mononuclear cells (PBMCs) when stimulated with a pneumococcal whole cell antigen (WCA). Levels of IFN-gamma were also decreased whilst IL-10 and IL-1 beta were increased. Effects of VitD(3) on innate responses following RSV stimulation was limited, only reducing IL-6. VitD(3) also reduced the number of TLR2+CD14+ monocytes, whilst increasing TLR7+CD14+ monocytes and TLR4+CD56+ NK cells. In WCA-stimulated PBMCs, VitD(3) increased IL-1 beta levels but reduced TLR2+CD14+ monocytes. For pneumococcal WCA-RSV co-stimulation, VitD(3) only had a limited effect, mainly through increased IL-1 beta and RANTES as well as TLR4+CD56+ NK cells. Our results suggest that VitD(3) can modulate the inflammatory response to pneumococci but has limited effects during viral or bacterial-viral exposure. This is the first study to examine the effects of VitD(3) in the context of pneumococcal-RSV co-stimulation, with important implications on the potential role of VitD(3) in the control of excessive inflammatory responses during pneumococcal and RSV infections.