title: Decreased progranulin levels in patients and rats with subarachnoid hemorrhage: a potential role in inhibiting inflammation by suppressing neutrophil recruitment.
abstract: BACKGROUND
  Subarachnoid hemorrhage (SAH) is a devastating neurological injury with high morbidity and mortality that is mainly caused by early brain injury (EBI). Progranulin (PGRN) is known to be involved in various biological functions, such as anti-inflammation and tissue repair. This study aimed to investigate the change of PGRN in the brain after SAH and its role on EBI.
  
  
  METHODS
  The levels of PGRN, myeloperoxidase (MPO), interleukin1β (IL-1β), and tumor necrosis factor-α (TNF-α) were detected in the cerebrospinal fluid (CSF) from SAH patients by enzyme-linked immunosorbent assay (ELISA). In addition, PGRN levels were also detected in the cerebral cortex after experimental SAH in rats by western blotting and immunohistochemistry (IHC). Recombinant human PGRN (r-PGRN) or an equal volume of phosphate-buffered saline (PBS) was administrated at 30 min after SAH. All rats were subsequently sacrificed at 24 h after SAH. Neurological score and brain water content were assessed. For mechanistic studies, the changes of MPO, matrix metalloproteinase-9 (MMP-9), zonula occludens 1 (ZO-1), Bcl-2, and cleaved caspase-3 were examined by western blotting and the levels of pro-inflammatory cytokines (IL-1β and TNF-α) were determined by ELISA. In addition, neuronal apoptosis and blood brain barrier (BBB) permeability were examined.
  
  
  RESULTS
  The levels of PGRN significantly decreased, and the levels of MPO, IL-1β, and TNF-α were markedly elevated in the CSF from SAH patients. In rats, PGRN levels in the brain also decreased after SAH. Administration of r-PGRN decreased brain water content and improved neurological scores at 24 h after SAH. These changes were associated with marked reductions in MPO, MMP-9, and proinflammation cytokine levels, as well as increased levels of Bcl-2 and ZO-1. In addition, neuronal apoptosis and BBB permeability were alleviated by r-PGRN.
  
  
  CONCLUSIONS
  These results indicate that the levels of PGRN decreased after SAH and that r-PGRN alleviates EBI after SAH possibly via inhibition of neutrophil recruitment, providing a new target for the treatment of SAH.
authors.affiliation: Department of Neurosurgery, Jinling Hospital, Medical School of Nanjing University, 210002, No. 305 Zhongshan East Road, Nanjing, Jiangsu Province, China. zhouchenhui1989@126.com.
authors.forename: Chenhui
authors.initials: C
authors.lastname: Zhou
authors.affiliation: Department of Neurosurgery, Jinling Hospital, Medical School of Nanjing University, 210002, No. 305 Zhongshan East Road, Nanjing, Jiangsu Province, China. xgb890803@sina.com.
authors.forename: Guangbin
authors.initials: G
authors.lastname: Xie
authors.affiliation: Department of Neurosurgery, Jinling Hospital, Medical School of Nanjing University, 210002, No. 305 Zhongshan East Road, Nanjing, Jiangsu Province, China. wangcx02@163.com.
authors.forename: Chunxi
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Neurosurgery, Jinling Hospital, School of Medicine, Second Military Medical University, Shanghai, China. zhang_zihuan@hotmail.com.
authors.forename: Zihuan
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Neurosurgery, School of Medicine, Southern Medical University (Guangzhou), Jinling Hospital, Nanjing, Jiangsu Province, China. chenqiang19901109@163.com.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Department of Neurosurgery, Jinling Hospital, Medical School of Nanjing University, 210002, No. 305 Zhongshan East Road, Nanjing, Jiangsu Province, China. 812579351@qq.com.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Neurosurgery, Jinling Hospital, Medical School of Nanjing University, 210002, No. 305 Zhongshan East Road, Nanjing, Jiangsu Province, China. wly_1680@sina.com.
authors.forename: Lingyun
authors.initials: L
authors.lastname: Wu
authors.affiliation: Department of Neurosurgery, Jinling Hospital, Medical School of Nanjing University, 210002, No. 305 Zhongshan East Road, Nanjing, Jiangsu Province, China. myfree2002@163.com.
authors.forename: Yongxiang
authors.initials: Y
authors.lastname: Wei
authors.affiliation: Department of Neurosurgery, School of Medicine, Southern Medical University (Guangzhou), Jinling Hospital, Nanjing, Jiangsu Province, China. njhd@outlook.com.
authors.forename: Hui
authors.initials: H
authors.lastname: Ding
authors.affiliation: Department of Neurosurgery, Jinling Hospital, Medical School of Nanjing University, 210002, No. 305 Zhongshan East Road, Nanjing, Jiangsu Province, China. hang_neurosurgery@163.com.
authors.forename: Chunhua
authors.initials: C
authors.lastname: Hang
authors.affiliation: Department of Neurosurgery, Jinling Hospital, Medical School of Nanjing University, 210002, No. 305 Zhongshan East Road, Nanjing, Jiangsu Province, China. mengliangzhou@yahoo.com.
authors.forename: Mengliang
authors.initials: M
authors.lastname: Zhou
authors.affiliation: Department of Neurosurgery, Jinling Hospital, Medical School of Nanjing University, 210002, No. 305 Zhongshan East Road, Nanjing, Jiangsu Province, China. shijx52@hotmail.com.
authors.forename: Jixin
authors.initials: J
authors.lastname: Shi
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D001812:Blood-Brain Barrier / Q000378:metabolism; D015153:Blotting, Western; D001921:Brain / Q000276:immunology / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007249:Inflammation / Q000276:immunology / Q000378:metabolism*; D036341:Intercellular Signaling Peptides and Proteins / Q000276:immunology / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D020556:Neutrophil Infiltration / Q000276:immunology*; D000077153:Progranulins; D051381:Rats; D017207:Rats, Sprague-Dawley; D013345:Subarachnoid Hemorrhage / Q000276:immunology / Q000378:metabolism*
chemical_list: C492314:GRN protein, human; D036341:Intercellular Signaling Peptides and Proteins; D000077153:Progranulins