Neuroprotectin D1 Attenuates Blast Overpressure Induced Reactive Microglial Cells in the Cochlea

Background: Microglia play a pivotal role in maintaining homeostasis in complex brain environment. They first exist as amoeboid microglial cells (AMCs) in the developing brain, but with brain maturation, they transform into ramified microglial cells (RMCs). In pathological conditions, microglia are activated and have been classified into M1 and M2 phenotypes. The roles of AMCs, RMCs and M1/M2 microglia phenotypes especially in pathological conditions have been the focus of many recent studies. Methods: Here, we review the early development of the AMCs and RMCs and discuss their specific functions with reference to their anatomic locations, immunochemical coding etc. M1 and M2 microglia phenotypes in different neuropathological conditions are also reviewed. Results: Activated microglia are engaged in phagocytosis, production of proinflammatory mediators, trophic factors and synaptogenesis etc. Prolonged microglia activation, however, can cause damage to neurons and oligodendrocytes. The M1 and M2 phenotypes featured prominently in pathological conditions are discussed in depth. Experimental evidence suggests that microglia phenotype is being modulated by multiple factors including external and internal stimuli, local demands, epigenetic regulation, and herbal compounds. Conclusion: Prevailing views converge that M2 polarization is neuroprotective. Thus, proper therapeutic designs including the use of anti-inflammatory drugs, herbal agents may be beneficial in suppression of microglial activation, especially M1 phenotype, for amelioration of neuroinflammation in different neuropathological conditions. Finally, recent development of radioligands targeting 18 kDa translocator protein (TSPO) in activated microglia may hold great promises clinically for early detection of brain lesion with the positron emission tomography.

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Piper sarmentosum Roxb. Root Extracts Confer Neuroprotection by Attenuating Beta Amyloid-Induced Pro-Inflammatory Cytokines Released from Microglial Cells

Current Alzheimer Research ◽

10.2174/1567205016666190228124630 ◽

2019 ◽

Vol 16 (3) ◽

pp. 251-260 ◽

Cited By ~ 4

Author(s):

Elaine Wan Ling Chan ◽

Emilia Tze Ying Yeo ◽

Kelly Wang Ling Wong ◽

Mun Ling See ◽

Ka Yan Wong ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Mrna Expression ◽

Inflammatory Mediators ◽

Beta Amyloid ◽

Microglial Cells ◽

Root Extracts ◽

Tnf Α ◽

P38α Mapk ◽

Anti Inflammatory ◽

Bv2 Microglial Cells

<P>Background: Alzheimer’s disease (AD) is a multifactorial neurodegenerative disorder that eventually leads to severe cognitive impairment. Although the exact etiologies of AD still remain elusive, increasing evidence suggests that neuroinflammation cascades mediated by microglial cells are associated with AD. Piper sarmentosum Roxb. (PS) is a medicinal plant reported to possess various biological properties, including anti-inflammatory, anti-psychotic and anti-oxidant activity. However, little is known about the anti-inflammatory activity of PS roots despite their traditional use to treat inflammatory- mediated ailments. Objective: This study aimed to evaluate the anti-inflammatory and neuroprotective properties of extracts obtained from the roots of PS against beta-amyloid (Aβ)-induced microglial toxicity associated with the production of pro-inflammatory mediators. Method: BV2 microglial cells were treated with hexane (RHXN), dichloromethane (RDCM), ethyl acetate (REA) and methanol (RMEOH) extracts of the roots of PS prior to activation by Aβ. The production and mRNA expression of pro-inflammatory mediators were evaluated by Griess reagent, ELISA kits and RT-qPCR respectively. The phosphorylation status of p38α MAPK was determined via western blot assay. BV2 conditioned medium was used to treat SH-SY5Y neuroblastoma cells and the neuroprotective effect was assessed using MTT assay. Results: PS root extracts, in particular RMEOH significantly attenuated the production and mRNA expression of IL-1β, IL-6 and TNF-α in Aβ-induced BV2 microglial cells. In addition, RHXN, REA and RMEOH extracts significantly reduced nitric oxide (NO) level and the inhibition of NO production was correlated with the total phenolic content of the extracts. Further mechanistic studies suggested that PS root extracts attenuated the production of cytokines by regulating the phosphorylation of p38α MAPK in microglia. Importantly, PS root extracts have protective effects against Aβ-induced indirect neurotoxicity either by inhibiting the production of NO, IL-1β, IL-6, and TNF-α in BV2 cells or by protecting SHSY5Y cells against these inflammatory mediators. Conclusions: These findings provided evidence that PS root extracts confer neuroprotection against Aβ- induced microglial toxicity associated with the production of pro-inflammatory mediators and may be a potential therapeutic agent for inflammation-related neurological conditions including Alzheimer’s disease (AD).</P>

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The Role of Microglial Cells on Neuroinflammation: Possible Therapeutic Applications

Recent Patents on Regenerative Medicine ◽

10.2174/2210296511202030172 ◽

2012 ◽

Vol 2 (3) ◽

pp. 172-184

Author(s):

Daniel M. de Oliveira ◽

Niels O.S. Camara ◽

Jean P.S. Peron

Keyword(s):

Microglial Cells ◽

Therapeutic Applications

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