Zhe Zhang, MD, Ph.D., PUMC Bo Yang, MD, Ph.D., UMMC 2014 JI Symposium UMHS-PUHSC JOINT INSTITUTE

Transcription

1 Identifying Smooth Muscle Cell Specific Proteins as Biomarkers for Early Diagnosis of Acute Aortic Dissection Zhe Zhang, MD, Ph.D., PUMC Bo Yang, MD, Ph.D., UMMC 2014 JI Symposium

2 A case of misdiagnosed acute type A aortic dissection (two days ago) 24 yo male

3 Aortic dissection - lethal 1-2%/h mortality Our center: operative mortality 5% Early diagnosis is the key 2/32

4 Current Diagnosis Method Computer Tomography (CT) Transesophageal Echocardiography (TEE) High suspicion of AAD Time consuming Incurs a further Logistical Delay in patient management 3

5 Management Delay In the United States, 50% of patients have a time to diagnosis of greater than 15 hours after the patients arrive at the hospital. In 25-50% Pts, the management could be delayed >24 hours 4

6 Ideal Biomarkers AMI TNI AAD 5

7 Composition of the Arterial Wall Adventitia Media Intima 6

8 Ideal Biomarkers The media of the aortic wall is composed mainly of Smooth Muscle Cells (SMC) and there is Extensive SMC Injury during AAD Investigate SMC-specific Proteins (sm22α, smmhc, sm-calponin, Smoothelin, and α-sma) for the Early Diagnosis of AAD. 7

9 Research Strategy Research Aims: Identify elevated proteins in the serum in patients of AAD using proteomics. Focusing on smooth muscle cell specific proteins, identify potential biomarkers for AAD. 8

10 Research Strategy Research Groups: Patients diagnosed with acute aortic dissection confirmed by imaging techniques. Patients diagnosed with acute coronary syndrome confirmed by elevated TNI and ECG. Healthy volunteers 9

11 Research Strategy Group A (n=3) Group B Group C (n=3) Blood samples (10 ml) are obtained within 24 hours of onset of chest pain Samples Samples Samples Identification and quantification of proteins by mass spectrometry Proteins Proteins Candidate Biomarkers Increase most significantly 10

12 Sample Preparation and Mass Spectrometry Analysis Human Serum 10ul serum was depleted of the 12 most abundant proteins* Human Aorta Tissue Homogenized, heated supernatant was filtered through a 0.45µm spin filter 20µg of total protein loaded on SDS-PAGE gel 20µg of total protein loaded on SDS-PAGE gel Entire gel lane excised into 40 equal segments and in-gel digestionusing trypsin (Promega) LC-MS/MS using a LTQ Orbitrap Velos mass spectrometer (Thermo Scientific) interfaced with Nano Acquity HPLC (Waters) Data analysis using Mascot (Matrix Science Ltd) and Scaffold (Proteome Software Inc) software packages Entire gel lane excised into 40 equal segments and in-gel digestionusing trypsin (Promega) LC-MS/MS using a LTQ Orbitrap Velos mass spectrometer (Thermo Scientific) interfaced with Nano Acquity HPLC (Waters) Data analysis using Mascot (Matrix Science Ltd) and Scaffold (Proteome Software Inc) software packages *The 12 most abundant proteins removed (using Depletion Spin columns from Pierce) are: Albumin, IgG, α1-acid Glycoprotein, α1-antitrypsin, α2-macroglobuin, Apolipoprotein A-I, Apolipoprotein A-II, Fibrinogen, Haptoglobin, IgA, IgM, Transferrin

13 Samples and Data Analysis Data Analysis Human Serum A total of 648 proteins were observed (false discovery rate of 0.9%) Protein profile and fold change calculation using the total Spectrum count 2-tailed, paired T-Test using the average spectral counts for both sample categories Differential protein expression was considered significant for fold changes >4 AND p-values of < proteins found to be present at low level amounts and differentially expressed between patient and control categories Data Analysis Human Aorta Tissue A total of 1240 proteins were observed (false discovery rate of 1%) Protein profile and total spectrum count recorded 10 of these significant serum proteins were also present in aorta tissue, most of them at significantly higher levels

14 13

15 Results: Top 4 differentially expressed proteins Human Serum (total average spectrum count/ number of unique peptides ) Vinculin (10/10) CD44 antigen (8/4) Bisphosphoglycerate mutase (7/5) Serum amyloid A-2 protein (9/5) Human Aorta Tissue (total spectrum count/number of unique peptides Vinculin (709/78) CD44 antigen (39/8 ) Bisphosphoglycerate mutase (20/10) Serum amyloid A-2 protein (7/2) Note: A minimum of 2 unique peptides is necessary to identify a protein in a sample.

16 Vinculin 116 kda, originally isolated from chicken gizzard smooth muscle in 1979, Human vinculin s structure was reported in 2007 cytoplasmic actin-binding protein enriched in focal adhesions and cell adherence junctions binds actin filament and the focal adhesion protein talin and α-actinin 15

17 16

18 Vinculin function Cell-ECM adhesion and Cell-Cell junctions Mechanical link, force generation, strength of adhesion regulates integrin clustering muscle-specific isoform, metavinculin, in SMCs and tissues Lost in Cancer Mutations are linked to DCM Increased expression in MFS aorta 17

19 Release vinculin during dissection 18

20 CD44 antigen

21 CD 44 Ag Cell surface protein Receptor of Hyaluronic acid Mediates Cell-cell and cell-ecm interaction has a crucial role in cell adhesion, inflammation, and repair processes 20/32

22 Bisphosphoglycerate mutase

23 Bisphosphoglycerate mutase main function is to synthesize the 2,3- bisphosphoglycerate (BPG) Chu WT etc. Phys Chem Chem Phys. 2014

24 Serum amyloid A-2 protein

25 Serum amyloid A-2 protein The precursor protein in inflammation-associated reactive amyloidosis (AA-type) An acute phase reactant whose level in the blood increases in response to various insults. expressed in the liver, but its physiological role is not well understood Expression studies show local production of SAA proteins in histologically normal, atherosclerotic, Alzheimer, inflammatory, and tumor tissues. Urieli-Shoval S etc. Curr Opin Hematol. 2000

26 SMC specific proteins α-actin smmhc Calponin Smoothlin Sm22α Caldesmon All were detected in the tissue, but either trace or none in the serum. No difference between two groups 25/32

27 Target Vinculin CD44 Ag Bisphosphoglycerate mutase 26/32

28 Next step Confirm our finding Dr. Yang (UM): Proteomics: AAD 3 pts <12 h ACS 3 pts <12 h Dr. Zhang (PKU): Proteomics: AAD 10 pts (5 pt <12h, 5 pts h) Control 10 pts (5 ACS pts, 5 healthy control) 27/32

29 Next step with a focusing on Viculin Confirm Viculin and other top 3 candidates in serum with Western Blot AAD 16 pts ACS 8 pts Healthy control 8 pts 28/32

30 Specific Aim 2 Group A n=185 Group B n=85 Group C n=40 Blood samples (10 ml) are obtained within 12 hours of onset of chest pain Samples Samples Samples Blood samples (10 ml) are obtained within 24 hours of onset of chest pain Samples Samples Compare the serum level of Viculin, CD 44 Ag, and bisphosphoglycerate mutase Biomarkers 29

31 Thanks! Thank You! 30

32 Ideal Biomarkers smmhc Smooth muscle myosin heavy chain (smmhc) was first studied. It is normally found at levels less than 0.9ng/ml in healthy individuals. smmhc with a dynamic range of approximately 20-fold higher levels in patients presenting early after symptom onset. 0.9±0.1 ng/ml Normal People 30.8±13.9 ng/ml AAD 31

33 Ideal Biomarkers smmhc Preliminary clinical testing has demonstrated Sensitivity and Specificity of 90% and 97% respectively, with a Diagnostic Accuracy of 96% at a cut off value of 2.5ng/ml, if performed within the first three hours of symptom onset. Sensitivity 90% 2.5ng/ml <3h Specificity 97% Accuracy 96% 32

34 Ideal Biomarkers smmhc These values significantly decline with Time, with Sensitivities of 72.4% and 30.3% at 6 and 9 hours respectively. 33

35 Ideal Biomarkers smmhc smmhc offered: favorable Discrimination and Diagnostic and Accuracy elevation were transient (3-6h) after AAD onset, similar to myoglobin in AMI. Narrow time window of use 34

36 Ideal Biomarkers sm-calponin Within vascular smooth muscle, calponin, a 34- kda protein that is troponin counterpart of smooth muscle has 3 isoforms: Basic (most abundant and specific), Acidic and Neutral 35

37 Ideal Biomarkers sm-calponin Researchers has reported that: Calponin Within 6h 6-12h 12-24h Basic >3-fold Still >3-fold Still elevated but continued to fall compared with previous Acidic >2-fold Continued to increase Neutral Did not demonstrate any elevation at any of the time 36

38 Ideal Biomarkers sm-calponin Researchers has reported that: Calponin Sensitivity Specificity Positive Predictive Values Negative Predictive Values Basic 63% 53% 73% 66% Acidic 50% 58% 87% 72%

39 Ideal Biomarkers sm-calponin sm-calponin offered: Satisfactory negative predictive value Poor positive predictive value Limiting use in clinic Further research would be required 38

40 Ideal Biomarkers sm22α sm22α, which we also call transgelin, is a 22kDa, 201-amino acid actin-binding protein expressed at high levels in smooth muscle cells. Transcribed from a 5.4 Kb gene located on chromosome 11q

41 Ideal Biomarkers sm22α Sm22α is one of the earliest markers of smooth muscle cell differentiation. 40

42 Ideal Biomarkers Smoothelin Smoothelin is a novel cytoskeletal protein that reacts with the 59kDa and 100kDa protein corresponding to Smoothelin A and B, which are exclusively found in smooth muscle cells. 41

43 Research Strategy Timeline: YEAR 1 Obtain IRB approval for the submission which is currently in preparation Identification of candidate biomarkers with proteomics 20 subjects at the University of Michigan and 40 subjects at Peking University YEAR 2 Complete the tasks outlined in Specific Aim 2 Identification of the SMC-specific proteins as candidate biomarkers for acute aortic dissection (AAD) with a larger sample size with known diagnosis 125 subjects at the University of Michigan, and 325 subjects at Peking University YEAR 3-5 Future Study Once we identify the biomarker candidates, we plan to continue studying the half-life and kinetics of those candidates to identify the time points of serum peak level of the biomarker candidates With the preliminary data gathered from years 1 and 2, we will apply for an NIH (USA) grant and National Science Foundation (China) for a clinical study with a larger sample size (1,000 patients), including using the samples from GenTAC to validate the candidate biomarkers in prospective cohorts of patients presenting with chest pain 42

44 Chest Pain Patients Within 12h YES Emergency Room Sign Informed Concent YES Take Blood Sample(10ml) Diagnose AAD ACS Within 12h YES YES Peking University for identification and quantification of proteins by mass spectrometry 43

45 Results Human Serum: Differentially Expressed Proteins (Uniprot accession number) Protein gamma (P61981) protein epsilon (P62258) Protein DJ-1 (PQ99497) Rho-GDP dissociation inhibitor 2 (P52566) Pro-Cathepsin H (P09668) Proteasome subunit beta type 6 (P28072) Vinculin (P18206) CD44 antigen (P16070) Bisphosphoglycerate mutase (P00738) Serum amyloid A-2 protein (P0DJI9) Low affinity immunoglobulin gamma FC region receptor III-A (P08637) Collagen alpha-1 (XVIII) chain (P39060) Proteins also present in Human Aorta Tissue (Uniprot accession number) Protein gamma (P61981) protein epsilon (P62258) Protein DJ-1 (PQ99497) Protein not observed Protein not observed Proteasome subunit beta type 6 (P28072) Vinculin (P18206) CD44 antigen (P16070) Bisphosphoglycerate mutase (P00738) Serum amyloid A-2 protein (P0DJI9) Low affinity immunoglobulin gamma FC region receptor III-A (P08637) Collagen alpha-1 (XVIII) chain (P39060)