title: Anti-inflammatory effects of BHBA in both in vivo and in vitro Parkinson's disease models are mediated by GPR109A-dependent mechanisms.
abstract: BACKGROUND
  Accumulating evidence suggests that neuroinflammation plays an important role in the progression of Parkinson's disease (PD). Excessively activated microglia produce several pro-inflammatory enzymes and pro-inflammatory cytokines, leading to damage to surrounding neurons and eventually inducing neurodegeneration. Therefore, the inhibition of microglial overactivation may be a potential therapeutic strategy to prevent the further progression of PD. β-Hydroxybutyric acid (BHBA) has been shown to suppress lipopolysaccharide (LPS)-induced inflammation in BV-2 cells and to protect dopaminergic neurons in previous studies, but the underlying mechanisms remain unclear. Thus, in this study, we further investigated this mechanism in LPS-induced in vivo and in vitro PD models.
  
  
  METHODS
  For the in vitro experiments, primary mesencephalic neuron-glia cultures were pretreated with BHBA and stimulated with LPS. [(3)H]dopamine (DA) uptake, tyrosine hydroxylase-immunoreactive (TH-ir) neurons and morphological analysis were evaluated and analyzed in primary mesencephalic neuron-glia cultures. In vivo, microglial activation and the injury of dopaminergic neurons were induced by LPS intranigral injection, and the effects of BHBA treatment on microglial activation and the survival ratio and function of dopaminergic neurons were investigated. Four our in vitro mechanistic experiment, primary microglial cells were pretreated with BHBA and stimulated with LPS; the cells were then assessed for the responses of pro-inflammatory enzymes and pro-inflammatory cytokines, and the NF-κB signaling pathway was evaluated and analyzed.
  
  
  RESULTS
  We found that BHBA concentration-dependently attenuated the LPS-induced decrease in [(3)H]DA uptake and loss of TH-ir neurons in the primary mesencephalic neuron/glia mixed culture. BHBA treatment significantly improved the motor dysfunction of the PD model rats induced by intranigral injection of LPS, and this beneficial effect of BHBA was attributed to the inhibition of microglial overactivation and the protection of dopaminergic neurons in the substantia nigra (SN). Our in vitro mechanistic study revealed that the inhibitory effect of BHBA on microglia was mediated by G-protein-coupled receptor 109A (GPR109A) and involved the NF-κB signaling pathway, causing the inhibition of pro-inflammatory enzyme (iNOS and COX-2) and pro-inflammatory cytokine (TNF-α, IL-1β, and IL-6) production.
  
  
  CONCLUSIONS
  In conclusion, the present study supports the effectiveness of BHBA in protecting dopaminergic neurons against inflammatory challenge.
authors.affiliation: College of Veterinary Medicine Jilin University, Changchun, 130062, P R China. shoupengfu@163.com.
authors.forename: Shou-Peng
authors.initials: SP
authors.lastname: Fu
authors.affiliation: College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, 163319, P R China. wjflw@sina.com.
authors.forename: Jian-Fa
authors.initials: JF
authors.lastname: Wang
authors.affiliation: College of Veterinary Medicine Jilin University, Changchun, 130062, P R China. Zhulingxue_1991@163.com.
authors.forename: Wen-Jing
authors.initials: WJ
authors.lastname: Xue
authors.affiliation: College of Veterinary Medicine Jilin University, Changchun, 130062, P R China. WOBUDENGYUXINGFU@126.com.
authors.forename: Hong-Mei
authors.initials: HM
authors.lastname: Liu
authors.affiliation: College of Veterinary Medicine Jilin University, Changchun, 130062, P R China. lhglbr@163.com.
authors.forename: Bing-run
authors.initials: BR
authors.lastname: Liu
authors.affiliation: College of Veterinary Medicine Jilin University, Changchun, 130062, P R China. 181161304@qq.com.
authors.forename: Ya-Long
authors.initials: YL
authors.lastname: Zeng
authors.affiliation: College of Veterinary Medicine Jilin University, Changchun, 130062, P R China. 380847810@qq.com.
authors.forename: Su-Nan
authors.initials: SN
authors.lastname: Li
authors.affiliation: College of Veterinary Medicine Jilin University, Changchun, 130062, P R China. huangbingxu123@163.com.
authors.forename: Bing-Xu
authors.initials: BX
authors.lastname: Huang
authors.affiliation: College of Veterinary Medicine Jilin University, Changchun, 130062, P R China. lvqingkang@hotmail.com.
authors.forename: Qing-Kang
authors.initials: QK
authors.lastname: Lv
authors.affiliation: College of Veterinary Medicine Jilin University, Changchun, 130062, P R China. wangwei@jluhp.edu.cn.|College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, 163319, P R China. wangwei@jluhp.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: College of Veterinary Medicine Jilin University, Changchun, 130062, P R China. juxiong@jlu.edu.cn.
authors.forename: Ju-Xiong
authors.initials: JX
authors.lastname: Liu
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000627:therapeutic use*; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002478:Cells, Cultured; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D004622:Embryo, Mammalian; D005786:Gene Expression Regulation / Q000187:drug effects; D007249:Inflammation / Q000188:drug therapy* / Q000209:etiology*; D008070:Lipopolysaccharides / Q000633:toxicity; D008297:Male; D008636:Mesencephalon / Q000166:cytology; D008840:Microfilament Proteins / Q000378:metabolism; D009457:Neuroglia / Q000187:drug effects; D009474:Neurons / Q000187:drug effects; D010300:Parkinson Disease / Q000150:complications* / Q000209:etiology; D051381:Rats; D017208:Rats, Wistar; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism*; D011978:Receptors, Nicotinic / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013239:Stereotyped Behavior / Q000187:drug effects
chemical_list: C491049:Aif1 protein, mouse; D000893:Anti-Inflammatory Agents; D002135:Calcium-Binding Proteins; D016207:Cytokines; C473652:Hcar2 protein, mouse; D008070:Lipopolysaccharides; D008840:Microfilament Proteins; D043562:Receptors, G-Protein-Coupled; D011978:Receptors, Nicotinic; D020155:3-Hydroxybutyric Acid