Dataset Information

Quantitative proteomics on pink1 mutant Drosophila melanogaster

ABSTRACT: Because pink1-mutant flies exhibit a global shutdown of protein synthesis, we decided to measure the levels of individual proteins in adult flies through quantitative proteomics.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Drosophila Melanogaster (fruit Fly)

TISSUE(S): Whole Body

SUBMITTER: Luis Martins

LAB HEAD: L. Miguel Martins

PROVIDER: PXD030979 | Pride | 2023-02-15

REPOSITORIES: Pride

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Project description:Tsetse flies (Glossina spp.) are major vectors of African trypanosomes, causing either Human or Animal African Trypanosomiasis (HAT or AAT). Several approaches are developed to control the disease among which the anti-vector Sterile Insect Technique. Another approach in the frame of anti-vector strategies could consist in controlling the fly’s vector competence which needs identifying factors (genes, proteins, biological pathways, …) involved in this process. The present work aims to verify whether protein candidates identified under experimental controlled conditions on insectary-reared tsetse flies have their counterpart in field-collected flies. Glossina palpalis palpalis flies naturally infected with Trypanosoma congolense were sampled in two HAT/AAT foci in Southern Cameroon. After dissection, the proteome from guts of parasite-infected flies were compared to that from uninfected flies in order to identify quantitative and/or qualitative changes associated to infection. A total of 3291 proteins were identified of which 1818 could be quantified. The comparative analysis allowed identifying 175 proteins with significant decreased abundance in infected as compared to uninfected flies, while 61 proteins displayed increased abundance. Among the former are RNA binding proteins, kinases, actin, ribosomal proteins, endocytosis proteins, oxido-reductases, as well as proteins that are unusually found such as tsetse salivary proteins (Tsal) or Yolk proteins. Among the proteins with increased abundance are fructose-1,6-biphosphatase, serine proteases, membrane trafficking proteins, death proteins (or apoptosis proteins), and SERPINs (inhibitor of serine proteases, enzymes considered as trypanosome virulence factors) that displayed highest increased abundance. Sodalis, Wiggleswothia and Wolbachia proteins are strongly under-represented, particularly when compared to data from similar experimentation conducted under controlled conditions on T. brucei gambiense infected (or uninfected) G. palpalis gambiensis insectary reared flies. Comparing the overall recorded data, 364 proteins identified in gut extracts from field flies were shown to have a homologue in insectary flies. Discrepancies between the two studies may arise from differences in the species of studied flies and trypanosomes as well as in differences in environmental conditions in which the two experiments were carried out. Finally, the present study together with former proteomic and transcriptomic studies on the secretome of trypanosomes, on the gut extracts from insectary reared and on field collected tsetse flies, provide a pool of data and information on which to draw in order to perform further investigations on, for example, mammal host immunization or on fly vector competence modification via para-transgenic approaches.

Project description:Drosophila melanogaster adult flies fed on normal food (NF) containing 16 mg/ml of pentylenetetrazole (PTZ) in the food show a hyperkinetic behavior within 24 hours. Half of that concentration, i.e., 8 mg/ml, of the PTZ, if fed for seven days, though doesn’t cause seizure-like behavior, results in a decreased climbing speed in flies. This change in locomotor behavior is progressive and becomes significant only on seventh day of the treatment. This climbing deficit is ameliorated when flies are treated concomitantly with PTZ and either of the two antiepileptic drugs (AEDs), sodium valproate (NaVP) or levetiracetam (LEV). Further experiments based on different regimes of combination and singular PTZ treatment demonstrated that whereas NaVP show a weaker prophylactic and stronger symptomatic effect, LEV exhibit an opposite effect, i.e., stronger prophylactic and weaker symptomatic action. These observations are consistent with the therapeutic effect of antiepileptic drugs. Time series of microarray gene expression profiling (earlier GEO submission) during chronic PTZ provided evidence of underlying downregulation of three main categories of biological processes, synaptic remodeling, energy metabolism and transport, in that order, in fly head. Transcriptomic analysis secondary to NaVP and LEV (earlier GEO submission) was found to cause statistically significant upregulation of two biological process categories each, energy metabolism and transport in case of NaVP and synaptic remodeling and energy metabolism in case of LEV. Time series of genome wide expression profiling secondary to PTZ and LEV combination treatment (earlier GEO submission) showed neutralizing effect of LEV on PTZ induced expression changes. Mining of published transcriptomic and proteomic data pertaining to epilepsy or established rodent animal models of epileptogenesis supported the relevance of the fly model in understanding the underlying brain pathophysiology. Systems modeling using RNA interference and small molecules demonstrated the robustness of the fly model. In brief, the above results clearly showed that the fly model is valuable not only in screening of antiepileptic, antiepileptogenic, disease-modifying and neuroprotective agents, but also in advancing our knowledge of mechanisms of action of drugs used in treating human patients suffering from various neurological and neuropsychiatric conditions, pharmacogenomics of these drugs, identification of potential drug targets, and selection of potential candidate genes for association analysis in epilepsy. Considering the above fly locomotor behavior model as relevant in kindling attainment, it was of obvious interest to study the behavioral and transcriptomic changes post-kindling, i.e., after withdrawing PTZ following seven day long chronic PTZ administration. It was observed that when PTZ is discontinued and flies climbing speed is monitored for next seven days of PTZ discontinuation, climbing speed deficit initially disappears and then a progressive increase in climbing speed is detected. Behavioral pharmacology of AEDs in post-kindling regime, like fly kindling described above, showed its usefulness in screening of potential antiepileptic, antiepileptogenic, disease-modifying and neuroprotective agents. The present submission relates to transcriptomic changes in fly head secondary to levetiracetam (LEV) treatment following discontinuation of PTZ for seven days (after seven days of chronic PTZ treatment). To delineate possible prophylactic or symptomatic effect of LEV at behavioral level, flies were treated with LEV for first three days and then shifted to NF for next four days (3 + 4 day regime) or flies treated with NF for first four days and then drug treated for next three days (4 + 3 day regime), in that order. At transcriptomic level, we have now examined the effect of LEV in 3 + 4 day regime. Gene expression profiles have been generated at both time points, 3rd and 7th day, i.e., on 10th and 14th day from the beginning of PTZ treatment. Effect of three day long chronic LEV treatment on fly head microarray gene expression profile, in otherwise normally grown flies, has already been determined (earlier GEO submission). Similarly, transcriptomic changes after one day, three days and seven days of PTZ discontinuation (i.e., 8th, 10th and 14th day of the beginning of chronic PTZ treatment) have already been deciphered (earlier GEO submission). Unlike the previous experiment in which flies were maintained in the same container during the post-kindling period of seven days, flies needed to be shifted in fresh vials once in the present experiment because of the demand of 3 + 4 day regime. Since change in housing conditions has the potential to influence head transcriptome, we have also generated microarray expression profile of fly head after treating flies with PTZ for seven days, maintaining the flies to NF containing vials for three days and then shifting and maintaining them in fresh NF containing vials for next four days (submitted in GEO previously). Keywords: Drug Response D. melanogaster Oregon-R wild type flies were grown in standard fly medium consisting of agar-agar, maize powder, brown sugar, dried yeast, and nipagin. The cultures were grown at 24 + 1oC, 60% RH, and 12 hrs light (9 AM to 9 PM) and 12 hours dark cycle. Three to four days old unmated adult males were grown in either normal food (NF) or food containing 8 mg/ml PTZ for seven days. Each treatment vial contained 30 flies in the beginning. Next, flies were treated in either of the following two manners: (1) shifted to vials containing 5 mg/ml LEV media for three days, and (2) shifted to LEV media for three days and then again shifted to fresh vials containing NF for next four days. Heads were harvested at the end of either of the two treatment conditions. For this, flies frozen in liquid nitrogen were shaken and the heads collected using cooled sieves. Total RNA was isolated from eight pools of frozen heads, every two of which represented a single parallel set of treatment in which four vials contained NF treated control flies, and four individuals treated in either one of the two ways described earlier, using TRI REAGENT (Sigma) according to the manufacturer’s protocol. Double stranded cDNA was synthesized from 10 µg of total RNA using Microarray cDNA Synthesis Kit (Roche). The cDNA was purified using Micorarray Target Purification Kit (Roche), according to the manufacturer’s protocol. Each of the four sets of control and treated cDNA samples, belonging to the four biological replicates, was used for labeling with either Cy3 or Cy5 dyes (Amersham Biosciences) using Microarray RNA Target Synthesis Kit T7 (Roche). The labeled products were purified by Microarray Target Purification Kit (Roche). The Cy3 and Cy5 labeled two cRNA samples of each biological replicate were pooled together, precipitated, washed, air-dried, and dissolved in 18MΩ RNAase free water (Sigma). Dye swapping was accomplished by hybridizing two arrays with NF control as Cy3- and LEV treated as Cy5- labeled sample, and the rest two as the opposite, NF as Cy5- and drug treated as Cy3- labeled sample. The labeled product was mixed with hybridization solution containing hybridization buffer (DIG Easy Hyb; Roche), 10 mg/ml salmon testis DNA (0.05 mg/ml final concentration, Sigma) and 10mg/ml yeast tRNA (0.05 mg/ml final concentration, Sigma). The hybridization mixture was denatured at 65ºC and applied onto cDNA microarray slides (D12Kv1, CDMC, Toronto, Canada). The slides were covered by a coverslip (ESCO, Portsmouth, USA) and hybridization was allowed to take place in hybridization chamber (Corning) at 37ºC for 16 hrs. Following hybridization, the coverslips were removed in a solution containing 1X SSC and 0.1% SDS at 50ºC, and the slides washed in 1X SSC and 0.1% SDS (three times for 15 minutes each) in a coplin jar at 50ºC with occasional swirling and then transferred to 1X SSC and washed with gentle swirling at room temperature (twice for 15 minutes each). Slides were given a final wash in 0.1X SSC for 15 minutes and then liquid was quickly removed from the slide surface by spinning at 600 rpm for 5 minutes. Slides were scanned at 10 µm resolution in GenePix 4000A Microarray Scanner (Molecular Devices). The preprocessing and quantification of the 16 bit TIFF images were carried out using Gene Pix Pro 6.0 software (Molecular Devices). Ratio based normalization was performed using Acuity 4.0 software (Molecular Devices). All Spots with raw intensity less then 100U and less then twice the average background was ignored during normalization. Normalized data was filtered for the selection of features before further analysis. Only those spot were selected which contained only a small percentage (<3) of saturated pixels, were not flagged bad or found absent (flags >= 0), had relatively uniform intensity and uniform background (Rgn R2 (635/532) >= 0.6) and were detectable above background (SNR >= 3). Analyzable spots in at least three of the four biological replicates performed were retrieved for downstream analysis using Significance Analysis of Microarrays (SAM 3, Excel Add-In, Stanford) under the conditions of one class response, imputation and 100 permutations.

Project description:Drosophila melanogaster adult flies fed on normal food (NF) containing 16 mg/ml of pentylenetetrazole (PTZ) in the food show a hyperkinetic behavior within 24 hours. Half of that concentration, i.e., 8 mg/ml, of the PTZ, if fed for seven days, though doesn’t cause seizure-like behavior, results in a decreased climbing speed in flies. This change in locomotor behavior is progressive and becomes significant only on seventh day of the treatment. This climbing deficit is ameliorated when flies are treated concomitantly with PTZ and either of the two antiepileptic drugs (AEDs), sodium valproate (NaVP) or levetiracetam (LEV). Further experiments based on different regimes of combination and singular PTZ treatment demonstrated that whereas NaVP show a weaker prophylactic and stronger symptomatic effect, LEV exhibit an opposite effect, i.e., stronger prophylactic and weaker symptomatic action. These observations are consistent with the therapeutic effect of antiepileptic drugs. Time series of microarray gene expression profiling (earlier GEO submission) during chronic PTZ provided evidence of underlying downregulation of three main categories of biological processes, synaptic remodeling, energy metabolism and transport, in that order, in fly head. Transcriptomic analysis secondary to NaVP and LEV (earlier GEO submission) was found to cause statistically significant upregulation of two biological process categories each, energy metabolism and transport in case of NaVP and synaptic remodeling and energy metabolism in case of LEV. Time series of genome wide expression profiling secondary to PTZ and LEV combination treatment (earlier GEO submission) showed neutralizing effect of LEV on PTZ induced expression changes. Mining of published transcriptomic and proteomic data pertaining to epilepsy or established rodent animal models of epileptogenesis supported the relevance of the fly model in understanding the underlying brain pathophysiology. Systems modeling using RNA interference and small molecules demonstrated the robustness of the fly model. In brief, the above results clearly showed that the fly model is valuable not only in screening of antiepileptic, antiepileptogenic, disease-modifying and neuroprotective agents, but also in advancing our knowledge of mechanisms of action of drugs used in treating human patients suffering from various neurological and neuropsychiatric conditions, pharmacogenomics of these drugs, identification of potential drug targets, and selection of potential candidate genes for association analysis in epilepsy. Considering the above fly locomotor behavior model as relevant in kindling attainment, it was of obvious interest to study the behavioral and transcriptomic changes post-kindling, i.e., after withdrawing PTZ following seven day long chronic PTZ administration. It was observed that when PTZ is discontinued and flies climbing speed is monitored for next seven days of PTZ discontinuation, climbing speed deficit initially disappears and then a progressive increase in climbing speed is detected. Behavioral pharmacology of AEDs in post-kindling regime, like fly kindling described above, showed its usefulness in screening of potential antiepileptic, antiepileptogenic, disease-modifying and neuroprotective agents. The present submission relates to transcriptomic changes in fly head secondary to vigabatrin (VGB) treatment following discontinuation of PTZ for seven days (after seven days of chronic PTZ treatment). To delineate possible prophylactic or symptomatic effect of VGB at behavioral level, flies were treated with VGB for first three days and then shifted to NF for next four days (3 + 4 day regime) or flies treated with NF for first four days and then drug treated for next three days (4 + 3 day regime), in that order. At transcriptomic level, we have now examined the effect of VGB in 3 + 4 day regime. Gene expression profiles have been generated at both time points, 3rd and 7th day, i.e., on 10th and 14th day from the beginning of PTZ treatment. Effect of three day long chronic VGB treatment on fly head microarray gene expression profile, in otherwise normally grown flies, has already been determined (earlier GEO submission). Similarly, transcriptomic changes after one day, three days and seven days of PTZ discontinuation (i.e., 8th, 10th and 14th day of the beginning of chronic PTZ treatment) have already been deciphered (earlier GEO submission). Unlike the previous experiment in which flies were maintained in the same container during the post-kindling period of seven days, flies needed to be shifted in fresh vials once in the present experiment because of the demand of 3 + 4 day regime. Since change in housing conditions has the potential to influence head transcriptome, we have also generated microarray expression profile of fly head after treating flies with PTZ for seven days, maintaining the flies to NF containing vials for three days and then shifting and maintaining them in fresh NF containing vials for next four days (submitted in GEO previously). D. melanogaster Oregon-R wild type flies were grown in standard fly medium consisting of agar-agar, maize powder, brown sugar, dried yeast, and nipagin. The cultures were grown at 24 + 1oC, 60% RH, and 12 hrs light (9 AM to 9 PM) and 12 hours dark cycle. Three to four days old unmated adult males were grown in either normal food (NF) or food containing 8 mg/ml PTZ for seven days. Each treatment vial contained 30 flies in the beginning. Next, flies were treated in either of the following two manners: (1) shifted to vials containing 24 mg/ml VGB media for three days, and (2) shifted to VGB media for three days and then again shifted to fresh vials containing NF for next four days. Heads were harvested at the end of either of the two treatment conditions. For this, flies frozen in liquid nitrogen were shaken and the heads collected using cooled sieves. Total RNA was isolated from eight pools of frozen heads, every two of which represented a single parallel set of treatment in which four vials contained NF treated control flies, and four individuals treated in either one of the two ways described earlier, using TRI REAGENT (Sigma) according to the manufacturer’s protocol. Double stranded cDNA was synthesized from 10 µg of total RNA using Microarray cDNA Synthesis Kit (Roche). The cDNA was purified using Micorarray Target Purification Kit (Roche), according to the manufacturer’s protocol. Each of the four sets of control and treated cDNA samples, belonging to the four biological replicates, was used for labeling with either Cy3 or Cy5 dyes (Amersham Biosciences) using Microarray RNA Target Synthesis Kit T7 (Roche). The labeled products were purified by Microarray Target Purification Kit (Roche). The Cy3 and Cy5 labeled two cRNA samples of each biological replicate were pooled together, precipitated, washed, air-dried, and dissolved in 18MΩ RNAase free water (Sigma). Dye swapping was accomplished by hybridizing two arrays with NF control as Cy3- and VGB treated as Cy5- labeled sample, and the rest two as the opposite, NF as Cy5- and drug treated as Cy3- labeled sample. The labeled product was mixed with hybridization solution containing hybridization buffer (DIG Easy Hyb; Roche), 10 mg/ml salmon testis DNA (0.05 mg/ml final concentration, Sigma) and 10mg/ml yeast tRNA (0.05 mg/ml final concentration, Sigma). The hybridization mixture was denatured at 65ºC and applied onto cDNA microarray slides (D12Kv1, CDMC, Toronto, Canada). The slides were covered by a coverslip (ESCO, Portsmouth, USA) and hybridization was allowed to take place in hybridization chamber (Corning) at 37ºC for 16 hrs. Following hybridization, the coverslips were removed in a solution containing 1X SSC and 0.1% SDS at 50ºC, and the slides washed in 1X SSC and 0.1% SDS (three times for 15 minutes each) in a coplin jar at 50ºC with occasional swirling and then transferred to 1X SSC and washed with gentle swirling at room temperature (twice for 15 minutes each). Slides were given a final wash in 0.1X SSC for 15 minutes and then liquid was quickly removed from the slide surface by spinning at 600 rpm for 5 minutes. Slides were scanned at 10 µm resolution in GenePix 4000A Microarray Scanner (Molecular Devices). The preprocessing and quantification of the 16 bit TIFF images were carried out using Gene Pix Pro 6.0 software (Molecular Devices). Ratio based normalization was performed using Acuity 4.0 software (Molecular Devices). All Spots with raw intensity less then 100U and less then twice the average background was ignored during normalization. Normalized data was filtered for the selection of features before further analysis. Only those spot were selected which contained only a small percentage (<3) of saturated pixels, were not flagged bad or found absent (flags >= 0), had relatively uniform intensity and uniform background (Rgn R2 (635/532) >= 0.6) and were detectable above background (SNR >= 3). Analyzable spots in at least three of the four biological replicates performed were retrieved for downstream analysis using Significance Analysis of Microarrays (SAM 3, Excel Add-In, Stanford) under the conditions of one class response, imputation and 100 permutations.

Project description:Drosophila melanogaster adult flies fed on normal food (NF) containing 16 mg/ml of pentylenetetrazole (PTZ) in the food show a hyperkinetic behavior within 24 hours. Half of that concentration, i.e., 8 mg/ml, of the PTZ, if fed for seven days, though doesn’t cause seizure-like behavior, results in a decreased climbing speed in flies. This change in locomotor behavior is progressive and becomes significant only on seventh day of the treatment. This climbing deficit is ameliorated when flies are treated concomitantly with PTZ and either of the two antiepileptic drugs (AEDs), sodium valproate (NaVP) or levetiracetam (LEV). Further experiments based on different regimes of combination and singular PTZ treatment demonstrated that whereas NaVP show a weaker prophylactic and stronger symptomatic effect, LEV exhibit an opposite effect, i.e., stronger prophylactic and weaker symptomatic action. These observations are consistent with the therapeutic effect of antiepileptic drugs. Time series of microarray gene expression profiling (earlier GEO submission) during chronic PTZ provided evidence of underlying downregulation of three main categories of biological processes, synaptic remodeling, energy metabolism and transport, in that order, in fly head. Transcriptomic analysis secondary to NaVP and LEV (earlier GEO submission) was found to cause statistically significant upregulation of two biological process categories each, energy metabolism and transport in case of NaVP and synaptic remodeling and energy metabolism in case of LEV. Time series of genome wide expression profiling secondary to PTZ and LEV combination treatment (earlier GEO submission) showed neutralizing effect of LEV on PTZ induced expression changes. Mining of published transcriptomic and proteomic data pertaining to epilepsy or established rodent animal models of epileptogenesis supported the relevance of the fly model in understanding the underlying brain pathophysiology. Systems modeling using RNA interference and small molecules demonstrated the robustness of the fly model. In brief, the above results clearly showed that the fly model is valuable not only in screening of antiepileptic, antiepileptogenic, disease-modifying and neuroprotective agents, but also in advancing our knowledge of mechanisms of action of drugs used in treating human patients suffering from various neurological and neuropsychiatric conditions, pharmacogenomics of these drugs, identification of potential drug targets, and selection of potential candidate genes for association analysis in epilepsy. Considering the above fly locomotor behavior model as relevant in kindling attainment, it was of obvious interest to study the behavioral and transcriptomic changes post-kindling, i.e., after withdrawing PTZ following seven day long chronic PTZ administration. It was observed that when PTZ is discontinued and flies climbing speed is monitored for next seven days of PTZ discontinuation, climbing speed deficit initially disappears and then a progressive increase in climbing speed is detected. Behavioral pharmacology of AEDs in post-kindling regime, like fly kindling described above, showed its usefulness in screening of potential antiepileptic, antiepileptogenic, disease-modifying and neuroprotective agents. The present submission relates to transcriptomic changes in fly head secondary to NaVP treatment following discontinuation of PTZ for seven days (after seven days of chronic PTZ treatment). To delineate possible prophylactic or symptomatic effect of NaVP at behavioral level, flies were treated with NaVP for first three days and then shifted to NF for next four days (3 + 4 day regime) or flies treated with NF for first four days and then drug treated for next three days (4 + 3 day regime), in that order. At transcriptomic level, we have now examined the effect of NaVP in 3 + 4 day regime. Gene expression profiles have been generated at both time points, 3rd and 7th day, i.e., on 10th and 14th day from the beginning of PTZ treatment. Effect of three day long chronic NaVP treatment on fly head microarray gene expression profile, in otherwise normally grown flies, has already been determined (earlier GEO submission). Similarly, transcriptomic changes after one day, three days and seven days of PTZ discontinuation (i.e., 8th, 10th and 14th day of the beginning of chronic PTZ treatment) have already been deciphered (earlier GEO submission). Unlike the previous experiment in which flies were maintained in the same container during the post-kindling period of seven days, flies needed to be shifted in fresh vials once in the present experiment because of the demand of 3 + 4 day regime. Since change in housing conditions has the potential to influence head transcriptome, we have also generated microarray expression profile of fly head after treating flies with PTZ for seven days, maintaining the flies to NF containing vials for three days and then shifting and maintaining them in fresh NF containing vials for next four days (submitted in GEO previously). D. melanogaster Oregon-R wild type flies were grown in standard fly medium consisting of agar-agar, maize powder, brown sugar, dried yeast, and nipagin. The cultures were grown at 24 + 1oC, 60% RH, and 12 hrs light (9 AM to 9 PM) and 12 hours dark cycle. Three to four days old unmated adult males were grown in either normal food (NF) or food containing 0.33 mg/ml PTZ for seven days. Each treatment vial contained 30 flies in the beginning. Next, flies were treated in either of the following two manners: (1) shifted to vials containing 24 mg/ml NaVP media for three days, and (2) shifted to NaVP media for three days and then again shifted to fresh vials containing NF for next four days. Heads were harvested at the end of either of the two treatment conditions. For this, flies frozen in liquid nitrogen were shaken and the heads collected using cooled sieves. Total RNA was isolated from eight pools of frozen heads, every two of which represented a single parallel set of treatment in which four vials contained NF treated control flies, and four individuals treated in either one of the two ways described earlier, using TRI REAGENT (Sigma) according to the manufacturer’s protocol. Double stranded cDNA was synthesized from 10 µg of total RNA using Microarray cDNA Synthesis Kit (Roche). The cDNA was purified using Micorarray Target Purification Kit (Roche), according to the manufacturer’s protocol. Each of the four sets of control and treated cDNA samples, belonging to the four biological replicates, was used for labeling with either Cy3 or Cy5 dyes (Amersham Biosciences) using Microarray RNA Target Synthesis Kit T7 (Roche). The labeled products were purified by Microarray Target Purification Kit (Roche). The Cy3 and Cy5 labeled two cRNA samples of each biological replicate were pooled together, precipitated, washed, air-dried, and dissolved in 18M? RNAase free water (Sigma). Dye swapping was accomplished by hybridizing two arrays with NF control as Cy3- and NaVP treated as Cy5- labeled sample, and the rest two as the opposite, NF as Cy5- and drug treated as Cy3- labeled sample. The labeled product was mixed with hybridization solution containing hybridization buffer (DIG Easy Hyb; Roche), 10 mg/ml salmon testis DNA (0.05 mg/ml final concentration, Sigma) and 10mg/ml yeast tRNA (0.05 mg/ml final concentration, Sigma). The hybridization mixture was denatured at 65ºC and applied onto cDNA microarray slides (D12Kv1, CDMC, Toronto, Canada). The slides were covered by a coverslip (ESCO, Portsmouth, USA) and hybridization was allowed to take place in hybridization chamber (Corning) at 37ºC for 16 hrs. Following hybridization, the coverslips were removed in a solution containing 1X SSC and 0.1% SDS at 50ºC, and the slides washed in 1X SSC and 0.1% SDS (three times for 15 minutes each) in a coplin jar at 50ºC with occasional swirling and then transferred to 1X SSC and washed with gentle swirling at room temperature (twice for 15 minutes each). Slides were given a final wash in 0.1X SSC for 15 minutes and then liquid was quickly removed from the slide surface by spinning at 600 rpm for 5 minutes. Slides were scanned at 10 µm resolution in GenePix 4000A Microarray Scanner (Molecular Devices). The preprocessing and quantification of the 16 bit TIFF images were carried out using Gene Pix Pro 6.0 software (Molecular Devices). Ratio based normalization was performed using Acuity 4.0 software (Molecular Devices). All Spots with raw intensity less then 100U and less then twice the average background was ignored during normalization. Normalized data was filtered for the selection of features before further analysis. Only those spot were selected which contained only a small percentage (<3) of saturated pixels, were not flagged bad or found absent (flags >= 0), had relatively uniform intensity and uniform background (Rgn R2 (635/532) >= 0.6) and were detectable above background (SNR >= 3). Analyzable spots in at least three of the four biological replicates performed were retrieved for downstream analysis using Significance Analysis of Microarrays (SAM 3, Excel Add-In, Stanford) under the conditions of one class response, imputation and 100 permutations.

Project description:Amyotrophic Lateral Sclerosis (ALS) is generally a late onset neurodegenerative disease. Mutations in the Cu/Zn superoxide dismutase 1 (SOD1) gene accounts for approximately 20% of familial ALS and 2% of all ALS cases. Although a number of hypothesis have been proposed to explain mutant SOD1 toxicity, the molecular mechanisms of the disease remain unclear. SOD1 linked ALS is thought to function in a non-cell autonomous manner such that the motoneurons are critical for the onset and glia contribute to the progress of the disease. To dissect the roles of motoneurons and glia, we used the Gal4-UAS system to determine gene expression changes following the expression of mutant human SOD1 (G85R) selectively in either motoneurons or glia, and concurrently in motoneurons and glia of flies. We conducted a microarray on young (5 days old) and old (45 days old) flies expressing G85R in these cell types and identified a number of genes involved in a variety of processes. The candidate genes identified by this screen may help elucidate the individual and combined contributions of motoneurons and glial cells in ALS. We used microarrays to evaluate the transcriptional profile of 5 day old and 45 day old flies expressing mutant human SOD1 (G85R) in a tissue specific manner in motoneurons, glia, and together in motoneurons and glia and compared the expression to flies expressing wild-type drosophila SOD1 controls. The Gal4-UAS system was used to drive tissue expression of either mutant human SOD1 (G85R) or wild-type drosophila SOD1 (dSOD1) in flies. Flies containing either the motoneuronal driver, D42-Gal4, the glial driver, M1B-Gal4, or the combined motoneuronal and glial drivers, D42+M1B-Gal4 were crossed to flies containing either mutant human SOD1, UAS-G85R, or wild-type drosophila SOD1, UAS-dSOD1, as a control. Adult male progeny were collected within 24 hours after eclosion and aged to 5 (5d) and 45 (45d) days old. Groups of 10 flies were maintained in vials of cornmeal agar food and transferred to fresh food every 5-7 days. For each Gal4-UAS line and each age, 3 biological replicates consisting of 40 whole flies were flash frozen in liquid nitrogen and used to isolate total RNA, for a total of 36 samples.

Project description:Drosophila melanogaster adult flies fed on normal food (NF) containing 16 mg/ml of pentylenetetrazole (PTZ) in the food show a hyperkinetic behavior within 24 hours. Half of that concentration, i.e., 8 mg/ml, of the PTZ, if fed for seven days, though doesn’t cause seizure-like behavior, results in a decreased climbing speed in flies. This change in locomotor behavior is progressive and becomes significant only on seventh day of the treatment. This climbing deficit is ameliorated when flies are treated concomitantly with PTZ and either of the two antiepileptic drugs (AEDs), sodium valproate (NaVP) or levetiracetam (LEV). Further experiments based on different regimes of combination and singular PTZ treatment demonstrated that whereas NaVP show a weaker prophylactic and stronger symptomatic effect, LEV exhibit an opposite effect, i.e., stronger prophylactic and weaker symptomatic action. These observations are consistent with the therapeutic effect of antiepileptic drugs. Time series of microarray gene expression profiling (earlier GEO submission) during chronic PTZ provided evidence of underlying downregulation of three main categories of biological processes, synaptic remodeling, energy metabolism and transport, in that order, in fly head. Transcriptomic analysis secondary to NaVP and LEV (earlier GEO submission) was found to cause statistically significant upregulation of two biological process categories each, energy metabolism and transport in case of NaVP and synaptic remodeling and energy metabolism in case of LEV. Time series of genome wide expression profiling secondary to PTZ and LEV combination treatment (earlier GEO submission) showed neutralizing effect of LEV on PTZ induced expression changes. Mining of published transcriptomic and proteomic data pertaining to epilepsy or established rodent animal models of epileptogenesis supported the relevance of the fly model in understanding the underlying brain pathophysiology. Systems modeling using RNA interference and small molecules demonstrated the robustness of the fly model. In brief, the above results clearly showed that the fly model is valuable not only in screening of antiepileptic, antiepileptogenic, disease-modifying and neuroprotective agents, but also in advancing our knowledge of mechanisms of action of drugs used in treating human patients suffering from various neurological and neuropsychiatric conditions, pharmacogenomics of these drugs, identification of potential drug targets, and selection of potential candidate genes for association analysis in epilepsy. Considering the above fly locomotor behavior model as relevant in kindling attainment, it was of obvious interest to study the behavioral and transcriptomic changes post-kindling, i.e., after withdrawing PTZ following seven day long chronic PTZ administration. It was observed that when PTZ is discontinued and flies climbing speed is monitored for next seven days of PTZ discontinuation, climbing speed deficit initially disappears and then a progressive increase in climbing speed is detected. Behavioral pharmacology of AEDs in post-kindling regime, like fly kindling described above, showed its usefulness in screening of potential antiepileptic, antiepileptogenic, disease-modifying and neuroprotective agents. The present submission relates to transcriptomic changes in fly head secondary to gabapentin (GBP) treatment following discontinuation of PTZ for seven days (after seven days of chronic PTZ treatment). To delineate possible prophylactic or symptomatic effect of GBP at behavioral level, flies were treated with GBP for first three days and then shifted to NF for next four days (3 + 4 day regime) or flies treated with NF for first four days and then drug treated for next three days (4 + 3 day regime), in that order. At transcriptomic level, we have now examined the effect of GBP in 3 + 4 day regime. Gene expression profiles have been generated at both time points, 3rd and 7th day, i.e., on 10th and 14th day from the beginning of PTZ treatment. Effect of three day long chronic GBP treatment on fly head microarray gene expression profile, in otherwise normally grown flies, has already been determined (earlier GEO submission). Similarly, transcriptomic changes after one day, three days and seven days of PTZ discontinuation (i.e., 8th, 10th and 14th day of the beginning of chronic PTZ treatment) have already been deciphered (earlier GEO submission). Unlike the previous experiment in which flies were maintained in the same container during the post-kindling period of seven days, flies needed to be shifted in fresh vials once in the present experiment because of the demand of 3 + 4 day regime. Since change in housing conditions has the potential to influence head transcriptome, we have also generated microarray expression profile of fly head after treating flies with PTZ for seven days, maintaining the flies to NF containing vials for three days and then shifting and maintaining them in fresh NF containing vials for next four days (submitted in GEO previously). D. melanogaster Oregon-R wild type flies were grown in standard fly medium consisting of agar-agar, maize powder, brown sugar, dried yeast, and nipagin. The cultures were grown at 24 + 1oC, 60% RH, and 12 hrs light (9 AM to 9 PM) and 12 hours dark cycle. Three to four days old unmated adult males were grown in either normal food (NF) or food containing 8 mg/ml PTZ for seven days. Each treatment vial contained 30 flies in the beginning. Next, flies were treated in either of the following two manners: (1) shifted to vials containing 16 mg/ml GBP media for three days, and (2) shifted to GBP media for three days and then again shifted to fresh vials containing NF for next four days. Heads were harvested at the end of either of the two treatment conditions. For this, flies frozen in liquid nitrogen were shaken and the heads collected using cooled sieves. Total RNA was isolated from eight pools of frozen heads, every two of which represented a single parallel set of treatment in which four vials contained NF treated control flies, and four individuals treated in either one of the two ways described earlier, using TRI REAGENT (Sigma) according to the manufacturer’s protocol. Double stranded cDNA was synthesized from 10 µg of total RNA using Microarray cDNA Synthesis Kit (Roche). The cDNA was purified using Micorarray Target Purification Kit (Roche), according to the manufacturer’s protocol. Each of the four sets of control and treated cDNA samples, belonging to the four biological replicates, was used for labeling with either Cy3 or Cy5 dyes (Amersham Biosciences) using Microarray RNA Target Synthesis Kit T7 (Roche). The labeled products were purified by Microarray Target Purification Kit (Roche). The Cy3 and Cy5 labeled two cRNA samples of each biological replicate were pooled together, precipitated, washed, air-dried, and dissolved in 18MΩ RNAase free water (Sigma). Dye swapping was accomplished by hybridizing two arrays with NF control as Cy3- and GBP treated as Cy5- labeled sample, and the rest two as the opposite, NF as Cy5- and drug treated as Cy3- labeled sample. The labeled product was mixed with hybridization solution containing hybridization buffer (DIG Easy Hyb; Roche), 10 mg/ml salmon testis DNA (0.05 mg/ml final concentration, Sigma) and 10mg/ml yeast tRNA (0.05 mg/ml final concentration, Sigma). The hybridization mixture was denatured at 65ºC and applied onto cDNA microarray slides (D12Kv1, CDMC, Toronto, Canada). The slides were covered by a coverslip (ESCO, Portsmouth, USA) and hybridization was allowed to take place in hybridization chamber (Corning) at 37ºC for 16 hrs. Following hybridization, the coverslips were removed in a solution containing 1X SSC and 0.1% SDS at 50ºC, and the slides washed in 1X SSC and 0.1% SDS (three times for 15 minutes each) in a coplin jar at 50ºC with occasional swirling and then transferred to 1X SSC and washed with gentle swirling at room temperature (twice for 15 minutes each). Slides were given a final wash in 0.1X SSC for 15 minutes and then liquid was quickly removed from the slide surface by spinning at 600 rpm for 5 minutes. Slides were scanned at 10 µm resolution in GenePix 4000A Microarray Scanner (Molecular Devices). The preprocessing and quantification of the 16 bit TIFF images were carried out using Gene Pix Pro 6.0 software (Molecular Devices). Ratio based normalization was performed using Acuity 4.0 software (Molecular Devices). All Spots with raw intensity less then 100U and less then twice the average background was ignored during normalization. Normalized data was filtered for the selection of features before further analysis. Only those spot were selected which contained only a small percentage (<3) of saturated pixels, were not flagged bad or found absent (flags >= 0), had relatively uniform intensity and uniform background (Rgn R2 (635/532) >= 0.6) and were detectable above background (SNR >= 3). Analyzable spots in at least three of the four biological replicates performed were retrieved for downstream analysis using Significance Analysis of Microarrays (SAM 3, Excel Add-In, Stanford) under the conditions of one class response, imputation and 100 permutations.

			Action	DRS
	Experiment_1.msf	Msf
	Experiment_1_F1.raw	Raw
	Experiment_1_F10.raw	Raw
	Experiment_1_F11.raw	Raw
	Experiment_1_F12.raw	Raw

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Quantitative proteomics on pink1 mutant Drosophila melanogaster

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