ORIGINAL ARTICLE From Analysis of Ischemic Mouse Brain Proteome to Identification of Human Serum Clusterin as a Potential Biomarker for Severity of Acute Ischemic Stroke Hailong Song 1,2 & Hui Zhou 1,2 & Zhe Qu 1,2 & Jie Hou 2,3 & Weilong Chen 4 & Weiwu Cai 4 & Qiong Cheng 5 & Dennis Y. Chuang 1,2,6 & Shanyan Chen 1,2 & Shuwei Li 7 & Jilong Li 2,3 & Jianlin Cheng 2,3 & C. Michael Greenlief 8 & Yuan Lu 9 & Agnes Simonyi 2,6 & Grace Y. Sun 1,2,6 & Chenghan Wu 4 & Jiankun Cui 1,2 & Zezong Gu 1,2 Received: 16 May 2018 /Revised: 1 November 2018 /Accepted: 11 November 2018 # Springer Science+Business Media, LLC, part of Springer Nature 2018 Abstract Ischemic stroke is a devastating neurological disease that can cause permanent brain damage, but to date, few biomarkers are available to reliably assess the severity of injury during acute onset. In this study, quantitative proteomic analysis of ischemic mouse brain detected the increase in expression levels of clusterin (CLU) and cystatin C (CST3). Since CLU is a secretary protein, serum samples (n = 70) were obtained from acute ischemic stroke (AIS) patients within 24 h of stroke onset and together with 70 matched health controls. Analysis of CLU levels indicated significantly higher levels in AIS patients than healthy controls (14.91 ± 4.03 vs. 12.79 ± 2.22 ng/L; P = 0.0004). Analysis of serum CST3 also showed significant increase in AIS patients as compared with healthy controls (0.90 ± 0.19 vs. 0.84 ± 0.12 ng/L; P = 0.0064). The serum values of CLU were also positively correlated with the NIH Stroke Scale (NIHSS) scores, the time interval after stroke onset, as well as major stroke risk factors associated with lipid profile. These data demonstrate that elevated levels of serum CLU and CST3 are independently associated with AIS and may serve as peripheral biomarkers to aid clinical assessment of AIS and its severity. This pilot study thus contributes to progress toward preclinical proteomic screening by using animal models and allows translation of results from bench to bedside. Keywords Biomarkers . Ischemic stroke . Clusterin . Cystatin C . Proteomics Introduction Stroke occurs upon sudden disruption of the brain’ s blood sup- ply and is a leading cause of permanent disability in the aging population. Acute ischemic stroke (AIS) is a devastating neu- rological condition that accounts for approximately 87% of all stroke cases [1–3]. If adequate circulation is restored within a short period of time, the ischemic brain tissue in affected Electronic supplementary material The online version of this article (https://doi.org/10.1007/s12975-018-0675-2) contains supplementary material, which is available to authorized users. * Zezong Gu guze@health.missouri.edu 1 Department of Pathology & Anatomical Sciences, University of Missouri, Columbia, MO 65211, USA 2 Center for Botanical Interaction Studies, University of Missouri, Columbia, MO 65211, USA 3 Computer Science, University of Missouri, Columbia, MO 65211, USA 4 Department of Neurology, the Second Affiliated Clinical College of Fujian University of Traditional Chinese Medicine, Fuzhou 350001, China 5 Department of Neurology, Fujian Provincial Hospital, Fuzhou 350001, China 6 Biochemistry, University of Missouri, Columbia, MO 65211, USA 7 Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA 8 Chemistry, University of Missouri, Columbia, MO 65211, USA 9 Xiphophorus Genetic Stock Center, Texas State University, San Marcos, TX 78666, USA Translational Stroke Research https://doi.org/10.1007/s12975-018-0675-2