Imaging mass spectrometry: a new tool to investigate the spatial organization of peptides and proteins in mammalian tissue sections

Chaurand, Pierre; Schwartz, Sarah; Caprioli, Richard M.

doi:10.1016/s1367-5931(02)00370-8

Cited by 230 publications

(189 citation statements)

References 33 publications

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“…Lately MALDI-TOF MS has become a popular method for quantitative analysis of biomolecules (oligonucleotides, proteins, glycoproteins, etc.) originating from various sample types (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) or even for imaging tissue sections (13)(14)(15)(16)(17)(18)(23)(24)(25)(26). At the same time, several studies discuss the non-quantitative nature of MALDI-TOF MS (7, 8, 13, 19, 22, 26 -30).…”

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confidence: 99%

Investigating the Quantitative Nature of MALDI-TOF MS

Szaéjli

Feheér

Medzihradszky

2008

Molecular & Cellular Proteomics

138

116

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MALDI-TOF MS has been applied by several groups to relative quantitative measurements. At the same time, the non-quantitative character of this method has been widely reported. We conducted experiments to test the reliability of this technique for quantitation using the statistical method of inverse confidence limit calculation for the first time in this context. The relationship between relative intensities of known amounts of standard peptides and their concentration ratios was investigated. We found that the concentration ratios determined by relative intensity measurements were highly inaccurate and strongly influenced by the molecular milieu of the sample analyzed. Thus, we emphasize the necessity of using the sample itself for calibration. We also performed experiments using an isotope-labeled derivative of the analyte as an internal standard for calibration line generation. As expected, the use of such standard led to a dramatic increase in precision and a less pronounced improvement in accuracy. We recommend performing a similar statistical analysis as a demonstration of reliability for every system where MALDI-TOF MS is used for quantitative measurements. Molecular & Cellular Proteomics 7: 2410 -2418, 2008.MALDI-TOF MS is a widely used analytical technique because of its excellent sensitivity, relatively high speed, and simplicity. As a consequence of producing mostly singly charged ions (1, 2) MALDI is especially suitable for mixture analysis. It is commonly used in proteomic studies (3) frequently without any prefractionation (4) as well as in the analysis of other biomolecules. Lately MALDI-TOF MS has become a popular method for quantitative analysis of biomolecules (oligonucleotides, proteins, glycoproteins, etc.) originating from various sample types (5-22) or even for imaging tissue sections (13)(14)(15)(16)(17)(18)(23)(24)(25)(26). At the same time, several studies discuss the non-quantitative nature of MALDI-TOF MS (7, 8, 13, 19, 22, 26 -30). The main problem of MALDI is its poor reproducibility (sample to sample and shot to shot), which makes most quantitative measurements quite difficult at best (19,27,31). This is especially true for complex samples. The presence of so-called hot spots or sweet spots is the main cause of the poor reproducibility and is therefore a factor strongly increasing measurement times and complicating automated measurements. Furthermore this phenomenon is one of the major factors hampering the use of MALDI MS for spatially resolved imaging (27). The reasons for sweet spot formation are not completely understood. It could be caused by variation in the amount and the crystallization of the matrix, the latter being a function of local analyte concentration. Dependence of signal intensities on the orientation of the matrix-analyte crystals relative to the spectrometer axis is also possible (27). The extent of hot spot formation depends strongly on the matrix used. For example, preparations with ␣-cyano-4-hydroxycinnamic acid (CHCA) 1 deliver relatively homogenous samples (...

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confidence: 99%

Investigating the Quantitative Nature of MALDI-TOF MS

Szaéjli

Feheér

Medzihradszky

2008

Molecular & Cellular Proteomics

138

116

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“…For example, a protein of molecular mass 4,964 Da was localized to the outer area of tumors and was identified as thymosin b4 (Tb4), an immuno-regulatory peptide that has ability to sequester cytoplasmic monomeric actin. This concept offers the tantalizing prospect that imaging MS may be used, for example, intra-operatively to assess the surgical margins of excised tumors (Chaurand, Schwartz, & Caprioli, 2002). The major limitation of this approach, as with other approaches for direct mass spectrometric analysis of complex tissue samples, is the difficulty to identify the protein for which molecular mass is detected.…”

Section: A Reducing Cellular Heterogeneitymentioning

confidence: 99%

Intact‐protein based sample preparation strategies for proteome analysis in combination with mass spectrometry

Wang

Hanash

2004

Mass Spectrometry Reviews

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The complexity of tissue and cell proteomes and the vast dynamic range of protein abundance present a formidable challenge for analysis that no one analytical technique can overcome. As a result, there is a need to integrate technologies to achieve the high-resolution and high-sensitivity analysis of complex biological samples. The combined technologies of separation science and biological mass spectrometry (Bio-MS) are the current workhorse in proteomics, and are continuing to evolve to meet the needs for high sensitivity and high throughput. They are relied upon for protein quantification, identification, and analysis of post-translational modifications (PTMs). The standard technique of two dimensional poly-acrylamide gel electrophoresis (2D PAGE) offers relatively limited resolution and sensitivity for the simultaneous analysis of all cellular proteins, with only the most highly abundant proteins detectable in whole cell or tissuederived samples. Hence, many alternative strategies are being explored. Numerous sample preparation procedures are currently available to reduce sample complexity and to increase the detectability of low-abundance proteins. Maintaining proteins intact during sample preparation has important advantages compared with strategies that digest proteins at an early step. These strategies include the ability to quantitate and recover proteins, and the assessment of PTMs. A review of current intact protein-based strategies for protein sample preparation prior to mass spectrometry (MS) is presented in the context of biomedically driven applications. # 2004 Wiley Periodicals, Inc., Mass Spec Rev 24: [413][414][415][416][417][418][419][420][421][422][423][424][425][426] 2005

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“…[39][40][41][42][43][44] Imaging Mass Spectrometry Mass spectrometry has been used for the in situ analyses of proteins in tissue sections and those obtained by laser capture microdissection, 53 thereby allowing imaging and comparison of protein expression between normal and disease tissues. [54][55][56][57][58][59][60][61] In this strategy, frozen tissue sections are applied to a MALDI plate and analyzed at regular spatial intervals. The mass spectral data obtained at different intervals are compared to yield a spatial distribution of masses (proteins) across the tissue section.…”

Section: Protein Expression Profilingmentioning

confidence: 99%