Isabelle Fournier | Université des Sciences et Technologies de Lille (Lille-1) (original) (raw)

Papers by Isabelle Fournier

Research paper thumbnail of Proteomic Analysis of the Spatio-temporal Based Molecular Kinetics of Acute Spinal Cord Injury Identifies a Time-and Segment-specific Window for Effective Tissue Repair

Spinal cord injury (SCI) represents a major debilitating health issue with a direct socioeconomic... more Spinal cord injury (SCI) represents a major debilitating health issue with a direct socioeconomic burden on the public and private sectors worldwide. Although several studies have been conducted to identify the molecular progression of injury sequel due from the lesion site, still the exact underlying mechanisms and pathways of injury development have not been fully elucidated. In this work, based on OMICs, 3D matrix-assisted laser desorption ion-ization (MALDI) imaging, cytokines arrays, confocal imaging we established for the first time that molecular and cellular processes occurring after SCI are altered between the lesion proximity, i.e. rostral and caudal segments nearby the lesion (R1-C1) whereas segments distant from R1-C1, i.e. R2-C2 and R3-C3 levels coexpressed factors implicated in neurogenesis. Delay in T regulators recruitment between R1 and C1 favor discrepancies between the two segments. This is also reinforced by presence of neurites outgrowth inhibitors in C1, absent in R1. Moreover, the presence of immunoglobulins (IgGs) in neu-rons at the lesion site at 3 days, validated by mass spec-trometry, may present additional factor that contributes to limited regeneration. Treatment in vivo with anti-CD20 one hour after SCI did not improve locomotor function and decrease IgG expression. These results open the door of a novel view of the SCI treatment by considering the C1 as the therapeutic target. Molecular & Cellular Proteomics 15: 10.1074/mcp.M115.057794, 2641–2670, 2016. Spinal cord injury (SCI) 1 belongs to the serious, currently incurable disorders of the central nervous system (CNS), that are often accompanied by a permanent disability (1). Most SCI are related to traumatic spinal cord damages induced by road trauma, falls, or sport injuries (diving). Among the hallmark features of SCI is the axonal disruption in the spinal cord, which is often caused by fractured intervertebral disc or vertebrate. This primary event is followed by a progressive cascade of secondary deleterious reactions spreading to the adjacent spared tissue leading to a worsening of the neuro-logical status (2, 3). Although axonal regeneration is initiated, it is hampered by a combination of local factors that include severe inflammation, lack of trophic support and development of an inhibitory scar-forming environment. In fact, the regen-erative capacity of the central nervous system is particularly challenged in SCI as multiple cues converge to act as a chemical and physical barrier for the repair process (4, 5). It is now acknowledged that inflammation is one of the major key player that determines abortive axonal repair in SCI. Thus, although the immune response is recognized as primordial to preserve tissue homeostasis, the spatio-temporal course of inflammation in SCI is not favorable to axonal regeneration. Acute inflammation develops hours to days following initial spinal cord trauma and is triggered by the axonal damage and

Research paper thumbnail of Top-down microproteomics bridged to MALDI MS imaging reveals the molecular physiome of brain regions

Tissue top-down microproteomics was performed on 3 brain regions, leading to the characterization... more Tissue top-down microproteomics was performed on 3 brain regions, leading to the characterization of 123 reference proteins. Moreover, 8 alternative proteins from alternative open reading frames (AltORF) were identified. Some proteins display specific posttranslational modification profiles or truncation linked to the brain regions and their functions.

Research paper thumbnail of Proteomic and transcriptomic investigation of acne vulgaris microcystic and papular lesions: Insights in the understanding of its pathophysiology

Biochimica et Biophysica Acta (BBA) - General Subjects, 2016

The pathogenesis of acne vulgaris involves several phases including androgen-dependent hyper-sebo... more The pathogenesis of acne vulgaris involves several phases including androgen-dependent hyper-seborrhea, colonization by Propionibacterium acnes, and inflammation. Recent investigations have shown that in fact P. acnes provokes the activation of the inflammasome present in macrophages and dendritic cells. This signaling pathway leads to excessive production of interleukin IL-1β, a proinflammatory cytokine. Nevertheless, these well-studied phenomena in acne fail to elucidate the mechanisms responsible for the appearance of different lesions. We investigate response pathways for specific acne lesions such as microcysts and papules using shot-gun proteomic followed by systemic biology and transcriptomic approaches. Results show that most of the proteins identified as differentially expressed between the normal and acne tissue biopsies associated with the immune system response were identified as highly or exclusively expressed in the papule biopsies. They were also expressed in microcysts, but in lower amounts compared to those in papules. These results are supported by the identification of CAMP factor protein produced by P. acnes in microcysts, indicating its enhanced proliferation in this type of lesion CONCLUSIONS: As CAMP factor protein was not detected in papule biopsies, we can see a clear delineation in the stages of progression of acne pathogenesis, which begins with a hyphenated inflammatory response in the papule stage, followed by imbalance of lipid production, which in turn triggers the enhanced proliferation of P. acnes. We demonstrate that expression inflammation varies across the two types of lesions, suggesting different pathways enhanced as a function of the progression of P. acnes.

Research paper thumbnail of Evaluation of non-supervised MALDI mass spectrometry imaging combined with microproteomics for glioma grade III classification

Biochimica et biophysica acta, Jan 24, 2016

An integrated diagnosis using molecular features is recommended in the 2016 World Health Organiza... more An integrated diagnosis using molecular features is recommended in the 2016 World Health Organization (WHO) classification. Our aim was to explore non-targeted molecular classification using MALDI mass spectrometry imaging (MALDI MSI) associated to microproteomics in order to classify anaplastic glioma by integration of clinical data. We used fresh-frozen tissue sections to perform MALDI MSI of proteins based on their digestion peptides after in-situ trypsin digestion of the tissue sections and matrix deposition by micro-spraying. The generated 70μm spatial resolution image datasets were further processed by individual or global segmentation in order to cluster the tissues according to their molecular protein signature. The clustering gives 3 main distinct groups. Within the tissues the ROIs (regions of interest) defined by these groups were used for microproteomics by micro-extraction of the tryptic peptides after on-tissue enzymatic digestion. More than 2500 proteins including 22 ...

Research paper thumbnail of The triterpene glycosides of Holothuria forskali: usefulness and efficiency as a chemical defense mechanism against predatory fish

Journal of Experimental Biology, 2011

More than 100 triterpene glycosides (saponins) have been characterized in holothuroids in the pas... more More than 100 triterpene glycosides (saponins) have been characterized in holothuroids in the past several decades. In particular, Holothuria forskali contains 26 saponins in its Cuvierian tubules and 12 in its body wall. This high diversity could be linked to a chemical defense mechanism, the most commonly accepted biological role for these secondary metabolites. We performed an integrated study of the body-wall saponins of H. forskali. The saponins are mainly localized in the epidermis and in the mesothelium of the body wall and appear to be released when the holothuroid is stressed. Among the saponins present in the epidermis, one (holothurinoside G) was detected in the seawater surrounding non-stressed holothuroids and three others (holohurinosides C and F, and desholothurin A) were secreted when the animals were stressed. In addition, two new congeners (detected at m/z 1301 and 1317) were also present in the immediate surroundings of stressed holothuroids. These new saponins do not originate from the epidermis and could come from an internal organ. Quantities of secreted saponins were very low compared with the body wall and Cuvierian tubules concentrations. At natural concentrations, saponins do not represent a threat to the health of predatory fish. The deterrent effect of saponins seems therefore to act as an aposematic signal, warning potential predators of the unpalatability of the holothuroid tissues.

Research paper thumbnail of Use of conjugates with linkers cleavable by photodissociation or fragmentation for mass spectrometry analysis of tissue sections

CITATION 1 READS 13 8 authors, including: Some of the authors of this publication are also workin... more CITATION 1 READS 13 8 authors, including: Some of the authors of this publication are also working on these related projects: Identification of factors of the acute phase of the inflammatory response in rat model of spinal cord injury View project Structural elucidation by mass spectrometry applied to metabolomics and MS/MS data bank View project Isabelle Fournier ML_consult 49 PUBLICATIONS 2,071 CITATIONS SEE PROFILE All content following this page was uploaded by Michel Salzet on 17 June 2015.

Research paper thumbnail of Direct profiling and MALDI Imaging in clinical proteomic

Molecular and cellular Proteomics, 2006

MALDI direct analysis and MALDI imaging of tissues have shown to be a very powerful tool by local... more MALDI direct analysis and MALDI imaging of tissues have shown to be a very powerful tool by localizing molecules in tissue and by avoiding extraction, pre-purification, separation. Nevertheless, this new method requires new developments to increase sensitivity and specificity. We propose here a new concept and evolutions of each step of MALDI Imaging analysis. New matrices called Ionic matrices were synthesized to be especially well adapted for a good crystallization, sensitivity and resolution compared to the classical matrices. ...

Research paper thumbnail of New insights in sample preparation for MALDI Imaging and new developments to approach specific MALDI imaging of the transcriptome

54 th ASMS Conference Proceedings, 2006

New insights in sample preparation for MALDI Imaging and new developments to approach specific MA... more New insights in sample preparation for MALDI Imaging and new developments to approach specific MALDI imaging of the transcriptome. I Fournier, R Lemaire, M Wisztorski, J Stauber, O Jardin-Mathe, C Van Camp, M Deschamps, G Proess, R Day, M Salzet 54 th ASMS Conference Proceedings, 2006. Abstract not available. 17 Instruments and Measurements(SO).

Research paper thumbnail of MALDI tissue imaging using conjugates cleavable by fast fragmentation

Research paper thumbnail of New developments in MALDI imaging mass spectrometry for pathological proteomic studies: introduction to a novel concept, the specific MALDI imaging

Mol. Cell. Proteomics, 2006

Research paper thumbnail of DNTP conjugated to peptide via a UV cleavable linker

Research paper thumbnail of Antibody conjugated to peptide via a UV cleavable linker

Research paper thumbnail of Correction: A New Safety Concern for Glaucoma Treatment Demonstrated by Mass Spectrometry Imaging of Benzalkonium Chloride Distribution in the Eye, an Experimental Study in Rabbits

Research paper thumbnail of Specific MALDI-MSI: TAG-MASS

Methods in Molecular Biology, 2010

MALDI imaging as a molecular mass spectrometry imaging technique (MSI) can provide accurate infor... more MALDI imaging as a molecular mass spectrometry imaging technique (MSI) can provide accurate information about molecular composition on a surface. The last decade of MSI development has brought the technology to clinical and biomedical applications as a complementary technique of MRI and other molecular imaging. Then, this IMS technique is used for endogenous and exogenous molecule detection in pharmaceutical and biomedical fields. However, some limitations still exist due to physical and chemical aspects, and sensitivity of certain compounds is very low. Thus, we developed a multiplex technique for fast detection of different compound natures. The multiplex MALDI imaging technique uses a photocleavable group that can be detect easily by MALDI instrument. These techniques of targeted imaging using Tag-Mass molecules allow the multiplex detection of compounds like antibodies or oligonucleotides. Here, we describe how we used this technique to detect huge proteins and mRNA by MALDI imaging in rat brain and in a model for regeneration; the leech.

Research paper thumbnail of New developments in MALDI imaging mass spectrometry for pathological proteomic studies: introduction to a novel concept, the specific MALDI imaging

Mol. Cell. Proteomics, 2006

Research paper thumbnail of Proteomic analyses of serous and endometrioid epithelial ovarian cancers: cases studies :molecular insights of a possible histological etiology of serous ovarian cancer

PROTEOMICS - Clinical Applications, 2013

Research paper thumbnail of Spectroimmunohistochemistry: A Novel Form of MALDI Mass Spectrometry Imaging Coupled to Immunohistochemistry for Tracking Antibodies

OMICS: A Journal of Integrative Biology, 2014

in-vivo Mass Spectrometry for guided surgery and real-time diagnosis View project Identification ... more in-vivo Mass Spectrometry for guided surgery and real-time diagnosis View project Identification of factors of the acute phase of the inflammatory response in rat model of spinal cord injury View project

Research paper thumbnail of The C-terminal fragment of the immunoproteasome PA28S (Reg alpha) as an early diagnosis and tumor-relapse biomarker: evidence from mass spectrometry profiling

Histochemistry and Cell Biology, 2012

Research paper thumbnail of MALDI Imaging Mass Spectrometry for Studying Cancer Diseases

Research paper thumbnail of Development of liquid microjunction extraction strategy for improving protein identification from tissue sections

Journal of Proteomics, 2013

MALDI Mass Spectrometry Imaging has shown important potential for molecular classification and pa... more MALDI Mass Spectrometry Imaging has shown important potential for molecular classification and pathology marker discovery. Protein markers identification is therefore of prime importance. Direct structural analysis from tissue sections has shown limitations for protein identification because of the high degree of complexity of tissues. Only proteins of major abundance are identified this way. On the contrary, conventional proteomics approaches clearly allow for reliable identification of complex protein extracts but do not provide fine correlation with protein location in their original context. Here is presented an approach to obtain identification of proteins of various abundances while keeping their localization within the section. On-tissue trypsin digestion followed by micro-extraction using a liquid micro-junction interface is an efficient strategy to extract tryptic peptides and further identify the associated proteins off tissues. It was shown that conventional Reverse Phase Liquid Chromatography separation on the extracted material followed by MS/MS analysis on a HR FTMS instrument enabled the identification of 1500 proteins on average with high confidence from an area of about 650 μm in diameter, which corresponds to an estimated number of 1900 cells in average.

Research paper thumbnail of Proteomic Analysis of the Spatio-temporal Based Molecular Kinetics of Acute Spinal Cord Injury Identifies a Time-and Segment-specific Window for Effective Tissue Repair

Spinal cord injury (SCI) represents a major debilitating health issue with a direct socioeconomic... more Spinal cord injury (SCI) represents a major debilitating health issue with a direct socioeconomic burden on the public and private sectors worldwide. Although several studies have been conducted to identify the molecular progression of injury sequel due from the lesion site, still the exact underlying mechanisms and pathways of injury development have not been fully elucidated. In this work, based on OMICs, 3D matrix-assisted laser desorption ion-ization (MALDI) imaging, cytokines arrays, confocal imaging we established for the first time that molecular and cellular processes occurring after SCI are altered between the lesion proximity, i.e. rostral and caudal segments nearby the lesion (R1-C1) whereas segments distant from R1-C1, i.e. R2-C2 and R3-C3 levels coexpressed factors implicated in neurogenesis. Delay in T regulators recruitment between R1 and C1 favor discrepancies between the two segments. This is also reinforced by presence of neurites outgrowth inhibitors in C1, absent in R1. Moreover, the presence of immunoglobulins (IgGs) in neu-rons at the lesion site at 3 days, validated by mass spec-trometry, may present additional factor that contributes to limited regeneration. Treatment in vivo with anti-CD20 one hour after SCI did not improve locomotor function and decrease IgG expression. These results open the door of a novel view of the SCI treatment by considering the C1 as the therapeutic target. Molecular & Cellular Proteomics 15: 10.1074/mcp.M115.057794, 2641–2670, 2016. Spinal cord injury (SCI) 1 belongs to the serious, currently incurable disorders of the central nervous system (CNS), that are often accompanied by a permanent disability (1). Most SCI are related to traumatic spinal cord damages induced by road trauma, falls, or sport injuries (diving). Among the hallmark features of SCI is the axonal disruption in the spinal cord, which is often caused by fractured intervertebral disc or vertebrate. This primary event is followed by a progressive cascade of secondary deleterious reactions spreading to the adjacent spared tissue leading to a worsening of the neuro-logical status (2, 3). Although axonal regeneration is initiated, it is hampered by a combination of local factors that include severe inflammation, lack of trophic support and development of an inhibitory scar-forming environment. In fact, the regen-erative capacity of the central nervous system is particularly challenged in SCI as multiple cues converge to act as a chemical and physical barrier for the repair process (4, 5). It is now acknowledged that inflammation is one of the major key player that determines abortive axonal repair in SCI. Thus, although the immune response is recognized as primordial to preserve tissue homeostasis, the spatio-temporal course of inflammation in SCI is not favorable to axonal regeneration. Acute inflammation develops hours to days following initial spinal cord trauma and is triggered by the axonal damage and

Research paper thumbnail of Top-down microproteomics bridged to MALDI MS imaging reveals the molecular physiome of brain regions

Tissue top-down microproteomics was performed on 3 brain regions, leading to the characterization... more Tissue top-down microproteomics was performed on 3 brain regions, leading to the characterization of 123 reference proteins. Moreover, 8 alternative proteins from alternative open reading frames (AltORF) were identified. Some proteins display specific posttranslational modification profiles or truncation linked to the brain regions and their functions.

Research paper thumbnail of Proteomic and transcriptomic investigation of acne vulgaris microcystic and papular lesions: Insights in the understanding of its pathophysiology

Biochimica et Biophysica Acta (BBA) - General Subjects, 2016

The pathogenesis of acne vulgaris involves several phases including androgen-dependent hyper-sebo... more The pathogenesis of acne vulgaris involves several phases including androgen-dependent hyper-seborrhea, colonization by Propionibacterium acnes, and inflammation. Recent investigations have shown that in fact P. acnes provokes the activation of the inflammasome present in macrophages and dendritic cells. This signaling pathway leads to excessive production of interleukin IL-1β, a proinflammatory cytokine. Nevertheless, these well-studied phenomena in acne fail to elucidate the mechanisms responsible for the appearance of different lesions. We investigate response pathways for specific acne lesions such as microcysts and papules using shot-gun proteomic followed by systemic biology and transcriptomic approaches. Results show that most of the proteins identified as differentially expressed between the normal and acne tissue biopsies associated with the immune system response were identified as highly or exclusively expressed in the papule biopsies. They were also expressed in microcysts, but in lower amounts compared to those in papules. These results are supported by the identification of CAMP factor protein produced by P. acnes in microcysts, indicating its enhanced proliferation in this type of lesion CONCLUSIONS: As CAMP factor protein was not detected in papule biopsies, we can see a clear delineation in the stages of progression of acne pathogenesis, which begins with a hyphenated inflammatory response in the papule stage, followed by imbalance of lipid production, which in turn triggers the enhanced proliferation of P. acnes. We demonstrate that expression inflammation varies across the two types of lesions, suggesting different pathways enhanced as a function of the progression of P. acnes.

Research paper thumbnail of Evaluation of non-supervised MALDI mass spectrometry imaging combined with microproteomics for glioma grade III classification

Biochimica et biophysica acta, Jan 24, 2016

An integrated diagnosis using molecular features is recommended in the 2016 World Health Organiza... more An integrated diagnosis using molecular features is recommended in the 2016 World Health Organization (WHO) classification. Our aim was to explore non-targeted molecular classification using MALDI mass spectrometry imaging (MALDI MSI) associated to microproteomics in order to classify anaplastic glioma by integration of clinical data. We used fresh-frozen tissue sections to perform MALDI MSI of proteins based on their digestion peptides after in-situ trypsin digestion of the tissue sections and matrix deposition by micro-spraying. The generated 70μm spatial resolution image datasets were further processed by individual or global segmentation in order to cluster the tissues according to their molecular protein signature. The clustering gives 3 main distinct groups. Within the tissues the ROIs (regions of interest) defined by these groups were used for microproteomics by micro-extraction of the tryptic peptides after on-tissue enzymatic digestion. More than 2500 proteins including 22 ...

Research paper thumbnail of The triterpene glycosides of Holothuria forskali: usefulness and efficiency as a chemical defense mechanism against predatory fish

Journal of Experimental Biology, 2011

More than 100 triterpene glycosides (saponins) have been characterized in holothuroids in the pas... more More than 100 triterpene glycosides (saponins) have been characterized in holothuroids in the past several decades. In particular, Holothuria forskali contains 26 saponins in its Cuvierian tubules and 12 in its body wall. This high diversity could be linked to a chemical defense mechanism, the most commonly accepted biological role for these secondary metabolites. We performed an integrated study of the body-wall saponins of H. forskali. The saponins are mainly localized in the epidermis and in the mesothelium of the body wall and appear to be released when the holothuroid is stressed. Among the saponins present in the epidermis, one (holothurinoside G) was detected in the seawater surrounding non-stressed holothuroids and three others (holohurinosides C and F, and desholothurin A) were secreted when the animals were stressed. In addition, two new congeners (detected at m/z 1301 and 1317) were also present in the immediate surroundings of stressed holothuroids. These new saponins do not originate from the epidermis and could come from an internal organ. Quantities of secreted saponins were very low compared with the body wall and Cuvierian tubules concentrations. At natural concentrations, saponins do not represent a threat to the health of predatory fish. The deterrent effect of saponins seems therefore to act as an aposematic signal, warning potential predators of the unpalatability of the holothuroid tissues.

Research paper thumbnail of Use of conjugates with linkers cleavable by photodissociation or fragmentation for mass spectrometry analysis of tissue sections

CITATION 1 READS 13 8 authors, including: Some of the authors of this publication are also workin... more CITATION 1 READS 13 8 authors, including: Some of the authors of this publication are also working on these related projects: Identification of factors of the acute phase of the inflammatory response in rat model of spinal cord injury View project Structural elucidation by mass spectrometry applied to metabolomics and MS/MS data bank View project Isabelle Fournier ML_consult 49 PUBLICATIONS 2,071 CITATIONS SEE PROFILE All content following this page was uploaded by Michel Salzet on 17 June 2015.

Research paper thumbnail of Direct profiling and MALDI Imaging in clinical proteomic

Molecular and cellular Proteomics, 2006

MALDI direct analysis and MALDI imaging of tissues have shown to be a very powerful tool by local... more MALDI direct analysis and MALDI imaging of tissues have shown to be a very powerful tool by localizing molecules in tissue and by avoiding extraction, pre-purification, separation. Nevertheless, this new method requires new developments to increase sensitivity and specificity. We propose here a new concept and evolutions of each step of MALDI Imaging analysis. New matrices called Ionic matrices were synthesized to be especially well adapted for a good crystallization, sensitivity and resolution compared to the classical matrices. ...

Research paper thumbnail of New insights in sample preparation for MALDI Imaging and new developments to approach specific MALDI imaging of the transcriptome

54 th ASMS Conference Proceedings, 2006

New insights in sample preparation for MALDI Imaging and new developments to approach specific MA... more New insights in sample preparation for MALDI Imaging and new developments to approach specific MALDI imaging of the transcriptome. I Fournier, R Lemaire, M Wisztorski, J Stauber, O Jardin-Mathe, C Van Camp, M Deschamps, G Proess, R Day, M Salzet 54 th ASMS Conference Proceedings, 2006. Abstract not available. 17 Instruments and Measurements(SO).

Research paper thumbnail of MALDI tissue imaging using conjugates cleavable by fast fragmentation

Research paper thumbnail of New developments in MALDI imaging mass spectrometry for pathological proteomic studies: introduction to a novel concept, the specific MALDI imaging

Mol. Cell. Proteomics, 2006

Research paper thumbnail of DNTP conjugated to peptide via a UV cleavable linker

Research paper thumbnail of Antibody conjugated to peptide via a UV cleavable linker

Research paper thumbnail of Correction: A New Safety Concern for Glaucoma Treatment Demonstrated by Mass Spectrometry Imaging of Benzalkonium Chloride Distribution in the Eye, an Experimental Study in Rabbits

Research paper thumbnail of Specific MALDI-MSI: TAG-MASS

Methods in Molecular Biology, 2010

MALDI imaging as a molecular mass spectrometry imaging technique (MSI) can provide accurate infor... more MALDI imaging as a molecular mass spectrometry imaging technique (MSI) can provide accurate information about molecular composition on a surface. The last decade of MSI development has brought the technology to clinical and biomedical applications as a complementary technique of MRI and other molecular imaging. Then, this IMS technique is used for endogenous and exogenous molecule detection in pharmaceutical and biomedical fields. However, some limitations still exist due to physical and chemical aspects, and sensitivity of certain compounds is very low. Thus, we developed a multiplex technique for fast detection of different compound natures. The multiplex MALDI imaging technique uses a photocleavable group that can be detect easily by MALDI instrument. These techniques of targeted imaging using Tag-Mass molecules allow the multiplex detection of compounds like antibodies or oligonucleotides. Here, we describe how we used this technique to detect huge proteins and mRNA by MALDI imaging in rat brain and in a model for regeneration; the leech.

Research paper thumbnail of New developments in MALDI imaging mass spectrometry for pathological proteomic studies: introduction to a novel concept, the specific MALDI imaging

Mol. Cell. Proteomics, 2006

Research paper thumbnail of Proteomic analyses of serous and endometrioid epithelial ovarian cancers: cases studies :molecular insights of a possible histological etiology of serous ovarian cancer

PROTEOMICS - Clinical Applications, 2013

Research paper thumbnail of Spectroimmunohistochemistry: A Novel Form of MALDI Mass Spectrometry Imaging Coupled to Immunohistochemistry for Tracking Antibodies

OMICS: A Journal of Integrative Biology, 2014

in-vivo Mass Spectrometry for guided surgery and real-time diagnosis View project Identification ... more in-vivo Mass Spectrometry for guided surgery and real-time diagnosis View project Identification of factors of the acute phase of the inflammatory response in rat model of spinal cord injury View project

Research paper thumbnail of The C-terminal fragment of the immunoproteasome PA28S (Reg alpha) as an early diagnosis and tumor-relapse biomarker: evidence from mass spectrometry profiling

Histochemistry and Cell Biology, 2012

Research paper thumbnail of MALDI Imaging Mass Spectrometry for Studying Cancer Diseases

Research paper thumbnail of Development of liquid microjunction extraction strategy for improving protein identification from tissue sections

Journal of Proteomics, 2013

MALDI Mass Spectrometry Imaging has shown important potential for molecular classification and pa... more MALDI Mass Spectrometry Imaging has shown important potential for molecular classification and pathology marker discovery. Protein markers identification is therefore of prime importance. Direct structural analysis from tissue sections has shown limitations for protein identification because of the high degree of complexity of tissues. Only proteins of major abundance are identified this way. On the contrary, conventional proteomics approaches clearly allow for reliable identification of complex protein extracts but do not provide fine correlation with protein location in their original context. Here is presented an approach to obtain identification of proteins of various abundances while keeping their localization within the section. On-tissue trypsin digestion followed by micro-extraction using a liquid micro-junction interface is an efficient strategy to extract tryptic peptides and further identify the associated proteins off tissues. It was shown that conventional Reverse Phase Liquid Chromatography separation on the extracted material followed by MS/MS analysis on a HR FTMS instrument enabled the identification of 1500 proteins on average with high confidence from an area of about 650 μm in diameter, which corresponds to an estimated number of 1900 cells in average.

Research paper thumbnail of Inter-and intra-organ spatial distributions of sea star saponins by MALDI imaging

Saponins are secondary metabolites that are abundant and diversified in echinoderms. Mass spectro... more Saponins are secondary metabolites that are abundant and diversified in echinoderms. Mass spectrometry is increasingly used not only to identify saponin congeners within animal extracts but also to decipher the structure/biological activity relationships of these molecules by determining their inter-organ and inter-individual variability. The usual method requires extensive purification procedures to prepare saponin extracts compatible with mass spectrometry analysis. Here, we selected the sea star Asterias rubens as a model animal to prove that direct analysis of saponins can be performed on tissue sections. We also demonstrated that carboxymethyl cellulose can be used as an embedding medium to facilitate the cryosectioning procedure. Matrix-assisted laser desorption/ ionization (MALDI) imaging was also revealed to afford interesting data on the distribution of saponin molecules within the tissues. We indeed highlight that saponins are located not only inside the body wall of the animals but also within the mucus layer that probably protects the animal against external aggressions.