Biomedical subjects

Joelle Vinh

Publications and source records attributed to Joelle Vinh.

6 recordsLinked to original sources

PubMed2025

Kinetic Redox Shotgun Proteomics Reveals Specific Lipopolysaccharide Effects on Intestinal Epithelial Cells, Mitigated by a Mn Superoxide Dismutase Mimic.

Overproduction of reactive oxygen species and antioxidant superoxide dismutases (SOD1, SOD2) dysregulation contribute to chronic inflammation such as generated in inflammatory bowel diseases (IBD). A kinetic redox shotgun proteomic strategy (OcSILAC for Oxidized cysteine Stable Isotope Labelling by Amino acids in Cell culture) was used to explore the lipopolysaccharide (LPS) effects including LPS-induced oxidation and inflammation cascades on a dedicated intestinal epithelial cell line (HT29-MD2) together with the potential mitigating role of a Mn-based SOD-mimic Mn1. While LPS induced transient oxidative damages at early times (15 min), cells incubated with Mn1 showed, in this time frame, a significantly reduced cysteine oxidation, highlighting Mn1 antioxidant properties. Over time, cysteine oxidation of LPS-treated cells was counteracted by an overexpression of antioxidant proteins (SOD1, NQO1) and a late (6 h) preponderant increase in SOD2 level. Mn1, when co-incubated with LPS, attenuated the level of most LPS-modified proteins, that is, proteins involved in the inflammatory response. Our results highlight Mn1 as a potentially effective antioxidant and anti-inflammatory agent to consider in the treatment of IBD, as well as a useful tool for exploring the interconnection between oxidative stress and inflammation.

Lipopolysaccharides↗

PubMed2006

PDMS-based microfluidics for proteomic analysis.

A microfluidic poly(dimethylsiloxane) (PDMS) microdevice was realized, combining on-line protein electrophoretic separation, selection, and digestion of a protein of interest for identification by mass spectrometry. The system includes eight integrated valves and one micropump dedicated to control the flow operations. Myoglobin was successfully isolated from bovine serum albumin (BSA), then selected using integrated valves and digested in a rotary micromixer. Proteolytic peptides were recovered from the micromixer for protein identification. Total analysis from sample injection to protein identification is performed under 30 minutes, with samples of tens of nanolitres. The paper shows that PDMS technology can be successfully used for integrating complex preparation protocols of proteic samples prior to MS analysis.

Journal Article↗

PubMed2005

Ribonucleases J1 and J2: two novel endoribonucleases in B.subtilis with functional homology to E.coli RNase E.

Many prokaryotic organisms lack an equivalent of RNase E, which plays a key role in mRNA degradation in Escherichia coli. In this paper, we report the purification and identification by mass spectrometry in Bacillus subtilis of two paralogous endoribonucleases, here named RNases J1 and J2, which share functional homologies with RNase E but no sequence similarity. Both enzymes are able to cleave the B.subtilis thrS leader at a site that can also be cleaved by E.coli RNase E. We have previously shown that cleavage at this site increases the stability of the downstream messenger. Moreover, RNases J1/J2 are sensitive to the 5' phosphorylation state of the substrate in a site-specific manner. Orthologues of RNases J1/J2, which belong to the metallo-beta-lactamase family, are evolutionarily conserved in many prokaryotic organisms, representing a new family of endoribonucleases. RNases J1/J2 appear to be implicated in regulatory processing/maturation of specific mRNAs, such as the T-box family members thrS and thrZ, but may also contribute to global mRNA degradation.

5' Untranslated Regions↗

PubMed2003

Proteomic study of human umbilical vein endothelial cells in culture.

The endothelium is a single layer of cells lining the inside face of all blood vessels. It constitutes a major metabolic organ which is critically involved in the generation and the regulation of multiple physiological and pathological processes such as coagulation, hemostasis, inflammation, atherosclerosis, angiogenesis and cancerous metastasis dissemination. In order to increase our knowledge about the protein content and the main biological pathways of human vascular endothelial cells, we have undertaken the proteomic analysis of the most explored present endothelial cell model, i.e. primocultures of human umbilical vein endothelial cells (HUVECs). Using low levels of protein loads (~ 30 nug), the association of two-dimensional electrophoresis with matrix-assisted laser desorption/ionization-time of flight mass spectrometry, liquid chromatography-tandem mass spectrometry and database interrogations allowed us to identify 53 proteins of suspected endothelial origin in quiescent HUVECs. Beside cytoskeletal proteins such as actin, tubulin, tropomyosin and vimentin, we identified various proteins more especially implicated in cellular motility and plasticity (e.g. cofilin, F-actin capping protein and prefoldin), in regulation of apoptosis and senescence (protease inhibitor 9, glucose related proteins, heat shock proteins, thioredoxin peroxidase, nucleophosmin) as well as other proteins implicated in coagulation (annexin V, high mobility group protein), antigen presentation (valosin containing protein and ubiquitin carboxyl terminal hydrolase isozyme L1) and enzymatic capabilities (glutathione-S-transferase, protein disulfide isomerases, lactate deshydrogenase). The presented annotated 2-D maps of HUVECs will be soon available on the web at http://www. huvec.com.

Cells, Cultured↗

PubMed2002

A thiol peroxidase is an H2O2 receptor and redox-transducer in gene activation.

The Yap1 transcription factor regulates hydroperoxide homeostasis in S. cerevisiae. Yap1 is activated by oxidation when hydroperoxide levels increase. We show that Yap1 is not directly oxidized by hydroperoxide. We identified the glutathione peroxidase (GPx)-like enzyme Gpx3 as a second component of the pathway, serving the role of sensor and transducer of the hydroperoxide signal to Yap1. When oxidized by H2O2, Gpx3 Cys36 bridges Yap1 Cys598 by a disulfide bond. This intermolecular disulfide bond is then resolved into a Yap1 intramolecular disulfide bond, the activated form of the regulator. Thioredoxin turns off the pathway by reducing both sensor and regulator. These data reveal a redox-signaling function for a GPx-like enzyme and elucidate a eukaryotic hydroperoxide-sensing mechanism. Gpx3 is thus a hydroperoxide receptor and redox-transducer.

Base Sequence↗

PubMed2002

Chimeric fusions of subunit IV and PetL in the b6f complex of Chlamydomonas reinhardtii: structural implications and consequences on state transitions.

The cytochrome b(6)f complex of Chlamydomonas reinhardtii contains four large subunits and at least three small ones, PetG, PetL, and PetM, whose role and location are unknown. Chimeric proteins have been constructed, in which the C terminus of subunit IV is fused to either one or the other of the two putative N termini of PetL. Biochemical and functional analysis of the chimeras together with mass spectrometry analysis of the wild-type (WT) complex led to the following conclusions: (i) neither a free subunit IV C terminus nor a free PetL N terminus is required for assembly of the b(6)f complex; (ii) the first AUG codon in the sequence of the gene petL is used for initiation; (iii) the N terminus of WT PetL lies in the lumen; (iv) in the WT complex, the N terminus of PetL and the C terminus of subunit IV are within reach of each other; (v) the purified b(6)f complex from C. reinhardtii contains an eighth, hitherto unrecognized subunit, PetN; and (vi) the ability to perform state transitions is lost in the chimeric mutants, although (vii) the Q-cycle is unaffected. A structural hypothesis is presented to account for this peculiar phenotype.

Amino Acid Sequence↗