Proteomic Analysis of Glutathione Transferases from Lucilia Cuprina

The glutathione transferases are a family of multifunctional enzymes involved in detoxification of xenobiotic and endogenous electrophilic compounds. Interest in insect GSTs has primarily focused on their role in insecticide resistance. The sheep blowfly, Lucilia cuprina is a major economic problem for the sheep meat and wool industries in Australasia and hence this thesis has attempted the study of the Lucilia cuprina GST family, using proteomics, with a view to eventually determining their role in insecticide resistance. Combinations of different affinity matrices (glutathione-Sepharose matrix (GSH) followed by dinitrophenyl-glutathione-Sepharose matrix (DNP-GSH)) and two-dimensional electrophoresis has successfully isolated members from major four insect GST classes: Sigma, Delta, Epsilon and Omega. Drosophila melanogaster has been used as a model insect throughout as a basis for comparison. To characterise Lucilia GSTs, the whole metazoan fragmentation database was used for sequence alignment with Lucilia peptides. This approach is broad and speculative but predicts a possible classification of the GSTs based on % similarity and % identity. This method of characterisation yielded match scores that provided a basis for classification, which must at present be regarded as tentative and in need of confirmation. In D. melanogaster and L. cuprina, GSH affinity-purified extracts showed the presence of only Sigma and Delta GSTs. In D. melanogaster, the DNP-GSH affinity-purified GSTs showed mostly the presence of Epsilon and Omega GSTs whereas in L. cuprina no Omega GSTs were detected. In both species, the migration pattern of Delta GST on 2D PAGE gel indicated possible post-translational modification. The results from analysis of LC-MS/MS data by the software PEAKS suggested deamidation at asparagine and glutamine residues in a limited number of the matched peptides of Delta GST. GST activity was present in all developmental stages of L. cuprina. The number of isoenzymes and their extent of expression vary as the insect develops. Delta GSTs were present in all developmental stages. The Sigma GST started expressing from the larval stage and was abundantly present in adult stage. The DNP-GSH affinity matrix purified GSTs which have been tentatively classified as Mu-like GSTs were present in egg, larvae and pupae but totally absent in adult stage. The GST families were characterised by proteomics in the main body sections of L. cuprina. Higher GST activity towards 1-chloro-2, 4-dinitrobenzene (CDNB) was found in the thorax (65.2 %) followed by the abdomen (19.6%) and the head (15.2%). The cytosolic GSTs of a resistant strain (PY81) of L. cuprina had significantly higher (2.26- and 2.6- fold) activity than the susceptible strains (NSW and CSIRO) towards CDNB and 2, 3-dichloro, 4-nitrobenzene (DCNB) respectively. The proteomic analysis of DNP-GSH purified extract from susceptible and resistant strains showed quantitatively higher expression of GSTs on 2D PAGE gel of the PY81 strain. The in vitro interaction of purified GSTs and model insecticides studied by high performance liquid chromatography revealed that Delta and DNP-GSH affinity-purified GSTs catalyse the conjugation of the insecticides to reduced glutathione but Sigma GST had almost no activity

A Proteomics Approach to Investigate miR-153-3p and miR-205-5p Targets in Neuroblastoma Cells

MicroRNAs are key regulators associated with numerous diseases. In HEK293 cells, miR-153-3p and miR-205-5p down-regulate alpha-synuclein (SNCA) and Leucine-rich repeat kinase 2 (LRRK2), two key proteins involved in Parkinson’s disease (PD). We have used two-dimensional gel electrophoresis (2D-PAGE) coupled to mass spectrometry (MS) to identify a spectrum of miR-153-3p and miR-205-5p targets in neuronal SH-SY5Y cells. We overexpressed and inhibited both microRNAs in SH-SY5Y cells and through comparative proteomics profiling we quantified ~240 protein spots from each analysis. Combined, thirty-three protein spots were identified showing significant (p-value \u3c 0.05) changes in abundance. Modulation of miR-153-3p resulted in seven up-regulated proteins and eight down-regulated proteins. miR-205 modulation resulted in twelve up-regulated proteins and six down-regulated proteins. Several of the proteins are associated with neuronal processes, including peroxiredoxin-2 and -4, cofilin-1, prefoldin 2, alpha-enolase, human nucleoside diphosphate kinase B (Nm23) and 14-3-3 protein epsilon. Many of the differentially expressed proteins are involved in diverse pathways including metabolism, neurotrophin signaling, actin cytoskeletal regulation, HIF-1 signaling and the proteasome indicating that miR-153-3p and miR-205-5p are involved in the regulation of a wide variety of biological processes in neuroblastoma cells

Proteomic Analysis of Glutathione Transferases from Lucilia Cuprina

The glutathione transferases are a family of multifunctional enzymes involved in detoxification of xenobiotic and endogenous electrophilic compounds. Interest in insect GSTs has primarily focused on their role in insecticide resistance. The sheep blowfly, Lucilia cuprina is a major economic problem for the sheep meat and wool industries in Australasia and hence this thesis has attempted the study of the Lucilia cuprina GST family, using proteomics, with a view to eventually determining their role in insecticide resistance. Combinations of different affinity matrices (glutathione-Sepharose matrix (GSH) followed by dinitrophenyl-glutathione-Sepharose matrix (DNP-GSH)) and two-dimensional electrophoresis has successfully isolated members from major four insect GST classes: Sigma, Delta, Epsilon and Omega. Drosophila melanogaster has been used as a model insect throughout as a basis for comparison. To characterise Lucilia GSTs, the whole metazoan fragmentation database was used for sequence alignment with Lucilia peptides. This approach is broad and speculative but predicts a possible classification of the GSTs based on % similarity and % identity. This method of characterisation yielded match scores that provided a basis for classification, which must at present be regarded as tentative and in need of confirmation. In D. melanogaster and L. cuprina, GSH affinity-purified extracts showed the presence of only Sigma and Delta GSTs. In D. melanogaster, the DNP-GSH affinity-purified GSTs showed mostly the presence of Epsilon and Omega GSTs whereas in L. cuprina no Omega GSTs were detected. In both species, the migration pattern of Delta GST on 2D PAGE gel indicated possible post-translational modification. The results from analysis of LC-MS/MS data by the software PEAKS suggested deamidation at asparagine and glutamine residues in a limited number of the matched peptides of Delta GST. GST activity was present in all developmental stages of L. cuprina. The number of isoenzymes and their extent of expression vary as the insect develops. Delta GSTs were present in all developmental stages. The Sigma GST started expressing from the larval stage and was abundantly present in adult stage. The DNP-GSH affinity matrix purified GSTs which have been tentatively classified as Mu-like GSTs were present in egg, larvae and pupae but totally absent in adult stage. The GST families were characterised by proteomics in the main body sections of L. cuprina. Higher GST activity towards 1-chloro-2, 4-dinitrobenzene (CDNB) was found in the thorax (65.2 %) followed by the abdomen (19.6%) and the head (15.2%). The cytosolic GSTs of a resistant strain (PY81) of L. cuprina had significantly higher (2.26- and 2.6- fold) activity than the susceptible strains (NSW and CSIRO) towards CDNB and 2, 3-dichloro, 4-nitrobenzene (DCNB) respectively. The proteomic analysis of DNP-GSH purified extract from susceptible and resistant strains showed quantitatively higher expression of GSTs on 2D PAGE gel of the PY81 strain. The in vitro interaction of purified GSTs and model insecticides studied by high performance liquid chromatography revealed that Delta and DNP-GSH affinity-purified GSTs catalyse the conjugation of the insecticides to reduced glutathione but Sigma GST had almost no activity.</p

Proteomic Analysis of Glutathione Transferases from Lucilia Cuprina

The glutathione transferases are a family of multifunctional enzymes involved in detoxification of xenobiotic and endogenous electrophilic compounds. Interest in insect GSTs has primarily focused on their role in insecticide resistance. The sheep blowfly, Lucilia cuprina is a major economic problem for the sheep meat and wool industries in Australasia and hence this thesis has attempted the study of the Lucilia cuprina GST family, using proteomics, with a view to eventually determining their role in insecticide resistance. Combinations of different affinity matrices (glutathione-Sepharose matrix (GSH) followed by dinitrophenyl-glutathione-Sepharose matrix (DNP-GSH)) and two-dimensional electrophoresis has successfully isolated members from major four insect GST classes: Sigma, Delta, Epsilon and Omega. Drosophila melanogaster has been used as a model insect throughout as a basis for comparison. To characterise Lucilia GSTs, the whole metazoan fragmentation database was used for sequence alignment with Lucilia peptides. This approach is broad and speculative but predicts a possible classification of the GSTs based on % similarity and % identity. This method of characterisation yielded match scores that provided a basis for classification, which must at present be regarded as tentative and in need of confirmation. In D. melanogaster and L. cuprina, GSH affinity-purified extracts showed the presence of only Sigma and Delta GSTs. In D. melanogaster, the DNP-GSH affinity-purified GSTs showed mostly the presence of Epsilon and Omega GSTs whereas in L. cuprina no Omega GSTs were detected. In both species, the migration pattern of Delta GST on 2D PAGE gel indicated possible post-translational modification. The results from analysis of LC-MS/MS data by the software PEAKS suggested deamidation at asparagine and glutamine residues in a limited number of the matched peptides of Delta GST. GST activity was present in all developmental stages of L. cuprina. The number of isoenzymes and their extent of expression vary as the insect develops. Delta GSTs were present in all developmental stages. The Sigma GST started expressing from the larval stage and was abundantly present in adult stage. The DNP-GSH affinity matrix purified GSTs which have been tentatively classified as Mu-like GSTs were present in egg, larvae and pupae but totally absent in adult stage. The GST families were characterised by proteomics in the main body sections of L. cuprina. Higher GST activity towards 1-chloro-2, 4-dinitrobenzene (CDNB) was found in the thorax (65.2 %) followed by the abdomen (19.6%) and the head (15.2%). The cytosolic GSTs of a resistant strain (PY81) of L. cuprina had significantly higher (2.26- and 2.6- fold) activity than the susceptible strains (NSW and CSIRO) towards CDNB and 2, 3-dichloro, 4-nitrobenzene (DCNB) respectively. The proteomic analysis of DNP-GSH purified extract from susceptible and resistant strains showed quantitatively higher expression of GSTs on 2D PAGE gel of the PY81 strain. The in vitro interaction of purified GSTs and model insecticides studied by high performance liquid chromatography revealed that Delta and DNP-GSH affinity-purified GSTs catalyse the conjugation of the insecticides to reduced glutathione but Sigma GST had almost no activity

Proteome analysis reveals roles of L-DOPA in response to oxidative stress in neurons

Background: Parkinson's disease (PD) is the second most common neurodegenerative movement disorder, caused by preferential dopaminergic neuronal cell death in the substantia nigra, a process also influenced by oxidative stress. L-3,4-dihydroxyphenylalanine (L-DOPA) represents the main treatment route for motor symptoms associated with PD however, its exact mode of action remains unclear. A spectrum of conflicting data suggests that L-DOPA may damage dopaminergic neurons due to oxidative stress whilst other data suggest that L-DOPA itself may induce low levels of oxidative stress, which in turn stimulates endogenous antioxidant mechanisms and neuroprotection. Results: In this study we performed a two-dimensional gel electrophoresis (2DE)-based proteomic study to gain further insight into the mechanism by which L-DOPA can influence the toxic effects of H2O2 in neuronal cells. We observed that oxidative stress affects metabolic pathways as well as cytoskeletal integrity and that neuronal cells respond to oxidative conditions by enhancing numerous survival pathways. Our study underlines the complex nature of L-DOPA in PD and sheds light on the interplay between oxidative stress and L-DOPA. Conclusions: Oxidative stress changes neuronal metabolic routes and affects cytoskeletal integrity. Further, L-DOPA appears to reverse some H2O2-mediated effects evident at both the proteome and cellular level

Verification of differentially expressed proteins by Western blot analysis and ROS changes in response to miR-153-3p and miR-205-5p.

<p>Western blot analysis showing effect of miR-153-3p mimic on (A) PRDX2 and HMGB1 levels (B) effect of miR-153-3p antagomir on Cfl1 levels, (C) effect of miR-205-5p mimic on PRDX2, NACA and Cfl1 levels, (D) effect of miR-205-5p antagomir on NACA and Cfl1 levels. (E) Quantification of ROS levels in SH-SY5Y cells by modulating miR-153-3p and miR-205-5p levels. Percentage change in DCF fluorescence compared to control is shown. (F) Proposed pathway for ROS reduction due to miR-153-3p and miR-205-5p by regulation of PRDX2. Error bars indicate SEM (n = 3); *, <i>p</i> < 0.05; **, <i>p</i> < 0.01, ***; <i>p</i> < 0.001.</p

List of differentially regulated proteins in SH-SY5Y cells in response to mimics and antagomirs of miR-153-3p and miR-205-5p.

<p>List of differentially regulated proteins in SH-SY5Y cells in response to mimics and antagomirs of miR-153-3p and miR-205-5p.</p