title: Texas 3-step decellularization protocol: looking at the cardiac extracellular matrix.
abstract: The extracellular matrix (ECM) is a critical tissue component, providing structural support as well as important regulatory signaling cues to govern cellular growth, metabolism, and differentiation. The study of ECM proteins, however, is hampered by the low solubility of ECM components in common solubilizing reagents. ECM proteins are often not detected during proteomics analyses using unbiased approaches due to solubility issues and relatively low abundance compared to highly abundant cytoplasmic and mitochondrial proteins. Decellularization has become a common technique for ECM protein-enrichment and is frequently used in engineering studies. Solubilizing the ECM after decellularization for further proteomic examination has not been previously explored in depth. In this study, we describe testing of a series of protocols that enabled us to develop a novel optimized strategy for the enrichment and solubilization of ECM components. Following tissue decellularization, we use acid extraction and enzymatic deglycosylation to facilitate re-solubilization. The end result is the generation of three fractions for each sample: soluble components, cellular components, and an insoluble ECM fraction. These fractions, developed in mass spectrometry-compatible buffers, are amenable to proteomics analysis. The developed protocol allows identification (by mass spectrometry) and quantification (by mass spectrometry or immunoblotting) of ECM components in tissue samples.
  
  
  CONCLUSIONS
  The study of extracellular matrix (ECM) proteins in pathological and non-pathological conditions is often hampered by the low solubility of ECM components in common solubilizing reagents. Additionally, ECM proteins are often not detected during global proteomic analyses due to their relatively low abundance compared to highly abundant cytoplasmic and mitochondrial proteins. In this manuscript we describe testing of a series of protocols that enabled us to develop a final novel optimized strategy for the enrichment and solubilization of ECM components. The end result is the generation of three fractions for each sample: soluble components, cellular components, and an insoluble ECM fraction. By analysis of each independent fraction, differences in protein levels can be detected that in normal conditions would be masked. These fractions are amenable to mass spectrometry analysis to identify and quantify ECM components in tissue samples. The manuscript places a strong emphasis on the immediate practical relevance of the method, particularly when using mass spectrometry approaches; additionally, the optimized method was validated and compared to other methodologies described in the literature.
authors.affiliation: San Antonio Cardiovascular Proteomics Center, USA. ldecastrobras@umc.edu
authors.forename: Lisandra E
authors.initials: LE
authors.lastname: de Castro Brás
authors.forename: Trevi A
authors.initials: TA
authors.lastname: Ramirez
authors.forename: Kristine Y
authors.initials: KY
authors.lastname: DeLeon-Pennell
authors.forename: Ying Ann
authors.initials: YA
authors.lastname: Chiao
authors.forename: Yonggang
authors.initials: Y
authors.lastname: Ma
authors.forename: Qiuxia
authors.initials: Q
authors.lastname: Dai
authors.forename: Ganesh V
authors.initials: GV
authors.lastname: Halade
authors.forename: Kevin
authors.initials: K
authors.lastname: Hakala
authors.forename: Susan T
authors.initials: ST
authors.lastname: Weintraub
authors.forename: Merry L
authors.initials: ML
authors.lastname: Lindsey
mesh_terms: D000478:Alkylation; D000818:Animals; D002021:Buffers; D002474:Cell-Free System; D005109:Extracellular Matrix / Q000737:chemistry*; D016326:Extracellular Matrix Proteins / Q000302:isolation & purification*; D008297:Male; D013058:Mass Spectrometry; D051379:Mice; D009203:Myocardial Infarction / Q000503:physiopathology; D009206:Myocardium / Q000166:cytology*; D010084:Oxidation-Reduction; D010434:Pepsin A / Q000378:metabolism; D040901:Proteomics / Q000379:methods*; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D012995:Solubility; D020257:Ventricular Remodeling / Q000502:physiology
chemical_list: D002021:Buffers; D016326:Extracellular Matrix Proteins; D012967:Sodium Dodecyl Sulfate; D010434:Pepsin A