Label free quantitative proteomic profiling of serum samples of intellectually disabled young patients revealed dysregulation of complement coagulation and cholesterol cascade systems

Intellectual disability is a heterogeneous disorder, diagnosed using intelligence quotient (IQ) score criteria. Currently, no specific clinical test is available to diagnose the disease and its subgroups due to inadequate understanding of the pathophysiology. Therefore, current study was designed to explore the molecular mechanisms involved in disease perturbation, and to identify potential biomarkers for disease diagnosis and prognosis. A total of 250 participants were enrolled in this study, including 200 intellectually disabled (ID) subjects from the subgroups (mild, moderate, and severe) with age and gender matched healthy controls (n = 50). Initially, IQ testing score and biochemical profile of each subject was generated, followed by label-free quantitative proteomics of subgroups of IQ and healthy control group through nano-LC/MS- mass spectrometry. A total of 310 proteins were identified, among them198 proteins were common among all groups. Statistical analysis (ANOVA) of the subgroups of ID showed 142 differentially expressed proteins, in comparison to healthy control group. From these, 120 proteins were found to be common among all subgroups. The remaining 22 proteins were categorized as exclusive proteins found only in disease subgroups. Furthermore, the hierarchical cluster analysis (HCL) of common significant proteins was also performed, followed by PANTHER protein classification and GO functional enrichment analysis. Results provides that the datasets of differentially expressed proteins, belong to the categories of immune / defense proteins, transfer carrier proteins, apolipoproteins, complement proteins, protease inhibitors, hemoglobin proteins etc., they are known to involvein immune system, and complement and coagulation pathway cascade and cholesterol metabolism pathway. Exclusively expressed 22 proteins were found to be disease stage specific and strong PPI network specifically those that have significant role in platelets activation and degranulation, such as Filamin A (FLNA). Furthermore, to validate the mass spectrometric findings, four highly significant proteins (APOA4, SAP, FLNA, and SERPING) were quantified by ELISA in all the study subjects. AUROC analysis showed a significant association of APOA4 (0.830), FLNA (0.958), SAP (0.754) and SERPING (0.600) with the disease. Apolipoprotein A4 (APOA4) has a significant role in cholesterol transport, and in modulation of glucose and lipid metabolism in the CNS. Similarly, FLNA has a crucial role in the nervous system, especially in the functioning of synaptic network. Therefore, both APOA4, and FLNA proteins represent good potential for candidate biomarkers for the diagnosis and prognosis of the intellectual disability. Overall, serum proteome of ID patients provides valuable information of proteins/pathways that are altered during ID progression.

Mass-spectrometric analysis of APOB polymorphism rs1042031 (G/T) and its influence on serum proteome of coronary artery disease patients: genetic-derived proteomics consequences

Genetic polymorphisms of apolipoprotein B gene (APOB) may result into serum proteomic perturbance in Coronary Artery Disease (CAD). The current case-control cohort of Pakistani subjects was designed to analyze the genetic influence of APOB rs1042031, (G/T) genotype on serum proteome. Subjects were categorized into two groups: CAD patients (n = 480) and healthy individuals (n = 220). For genotyping, tetra ARMS-PCR was carried out and validated through sequencing, whereas LC/MS-based proteomic analysis of serum samples was performed through label-free quantification. In initial step of genotyping, the frequencies of each genotype GG, GT, and TT were 70%, 27%, and 30% in CAD patients, while in control group, the subjects were 52%, 43%, and 5%, respectively, in CAD patients. The genotypic frequencies in patients vs. control groups found significantly different (p = 0.004), and a strong association of dominant alleles GG with the CAD was observed in both dominant (OR: 2.4 (1.71-3.34), p = 0.001) and allelic genetic models (OR: 2.0 (1.45-2.86), p = 0.001). In second step of label-free quantitation, a total of 40 significant proteins were found with altered expression in CAD patients. The enriched Gene Ontology (GO) terms of molecular functions and pathways of these protein showed upregulated pathways as follows: chylomicron remodeling and assembly, complement cascade activation, plasma lipoprotein assembly, apolipoprotein-A receptor binding, and metabolism of fat-soluble vitamins in G allele carrier of rs1042031 (G > T) vs. mutant T-allele carriers. This study provides better understanding of CAD pathobiology by proteogenomics of APOB. It evidences the influence of APOB rs1042031-dominant (GG) genotype with CAD patients.

Quantitative Phosphoproteomics and Acetylomics of Safranal Anticancer Effects in Triple-Negative Breast Cancer Cells

Safranal, as an aroma in saffron, is one of the cytotoxic compounds in saffron that causes cell death in triple-negative breast cancer cells. Our recent research reported the anti-cancer effects of safranal, which further demonstrated its impact on protein translation, mitochondrial dysfunction, and DNA fragmentation. To better understand the underlying mechanisms, we identified acetylated and phosphorylated peptides in safranal-treated cancer cells. We conducted a comprehensive phosphoproteomics and acetylomics analysis of safranal-treated MDA-MB-231 cells by using a combination of TMT labeling and enrichment methods including titanium dioxide and immunoprecipitation. We provide a wide range of phosphoproteome regulation in different signaling pathways that are disrupted by safranal treatment. Safranal influences the phosphorylation level on proteins involved in DNA replication and repair, translation, and EGFR activation/accumulation, which can lead the cells into apoptosis. Safranal causes DNA damage which is followed by the activation of cell cycle checkpoints for DNA repair. Over time, checkpoints and DNA repair are inhibited and cells are under a mitotic catastrophe. Moreover, safranal prevents repair by the hypo-acetylation of H4 and facilitates the transcription of proapoptotic genes by hyper-acetylation of H3, which push the cells to the brink of death.

Abstract 116: Proof Of Biological Activity And Exploration Of Early Signaling Events Of Angiotensin-(1-5)

Introduction: Recombinant human ACE2 increases the circulating levels of angiotensin-(1-5) [Ang-(1-5)], a peptide thus far regarded as biologically inactive. Since ACE2 is a central component of the protective RAS, we hypothesized that Ang-(1-5) is a new biologically active peptide within this hormonal system.

Objective: To investigate biological activity and signaling mechanisms of Ang-(1-5).

Methods: In order to show a biological effect and to test whether Ang-(1-5) signals through the AT 2 -receptor (AT 2 R), nitric oxide (NO) release was measured by DAF-FM fluorescence in AT 2 R transfected (AT 2 R-CHO) or non-transfected (NT-CHO) CHO cells, treated with Ang-(1-5) or C21 (AT 2 R agonist, positive control) (0.1nM to 10μM) for 15 minutes. Vehicle (cell media) treated cells served as negative control. To investigate Ang-(1-5) signaling patterns, human aortic endothelial cells (HAEC) were treated with vehicle or Ang-(1-5) (1μM) for 1, 3, 5 or 20 minutes. Proteins were harvested, digested and labeled with TMTpro-16plex. Phosphopeptide enrichment was carried out by TiO 2 . Samples were subjected to LC-MS/MS analysis and the resulting mass spectra were searched against the human SwissProt database.

Results: Ang-(1-5) induced a concentration-dependent increase in NO production in AT 2 -CHO cells (E max : 65.60 ± 14.02%), thus proving its biological activity. Ang-(1-5) had 69% higher efficacy than the established AT 2 R agonist C21 (E max : 38.76 ± 10.24%). Ang-(1-5) seems to signal through the AT 2 R, because effects on NO release were absent in NT-CHO cells. Treatment of HAEC with Ang-(1-5) significantly modified the phosphorylation status of 831 proteins at 1799 residues. The majority of residues (1079) were dephosphorylated while 729 residues were phosphorylated. Changes in protein phosphorylation in response to Ang-(1-5) occurred at all investigated time points, most of them after 20 minutes. Functional bioinformatic analysis revealed a cluster of proteins involved in cell cycle and cell division regulation.

Conclusion: This study provides evidence that Ang-(1-5) is an endogenous AT 2 R agonist with high efficacy towards the AT 2 R. The early signaling phosphorylation pattern resembles those of other protective RAS agonists, such as C21 and Ang-(1-7).

Proteomes of Uropathogenic Escherichia coli Growing in Human Urine and in J82 Urinary Bladder Cells

Uropathogenic Escherichia coli (UPEC) are the most common cause of urinary tract infection (UTI). UPEC normally reside in the intestine, and during establishment of UTI, they undergo metabolic adaptations, first to urine and then upon tissue invasion to the bladder cell interior. To understand these adaptations, we used quantitative proteomic profiling to characterize protein expression of the UPEC strain UTI89 growing in human urine and when inside J82 bladder cells. In order to facilitate detection of UPEC proteins over the excess amount of eukaryotic proteins in bladder cells, we developed a method where proteins from UTI89 grown in MOPS and urine was spiked-in to enhance detection of bacterial proteins. More than 2000 E. coli proteins were detected. During growth in urine, proteins associated with iron acquisition and several amino acid uptake and biosynthesis systems, most prominently arginine metabolism, were significantly upregulated. During growth in J82 cells, proteins related to iron uptake and arginine metabolisms were likewise upregulated together with proteins involved in sulfur compound turnover. Ribosomal proteins were downregulated relative to growth in MOPS in this environment. There was no direct correlation between upregulated proteins and proteins reported to be essential for infections, showing that upregulation during growth does not signify that the proteins are essential for growth under a condition.

Comprehensive proteomics and sialiomics of the anti-proliferative activity of safranal on triple negative MDA-MB-231 breast cancer cell lines

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with no efficient treatment. Researchers have indicated the importance of quantitative approaches on proteome and different post-translation modifications studies both in diagnosis and treatment purposes. Sialic acid-containing glycopeptides (the sialiome) is one of these modifications which can be used as a tool in cancer diagnosis or therapeutic strategies since the sialylation is strongly associated with cancer migration and metastasis. Based on our study, safranal, which is a non-toxic compound in orally intakes, exhibits a significant cytotoxic effect on MDA-MB-231 in comparison to normal cells. We conducted a comprehensive proteomics and sialiomics analysis of safranal treated MDA-MB-231 cells by using a combination of TMT labeling and titanium dioxide enrichment of sialylated N-linked glycopeptides to investigate the underlying molecular mechanism behind safranal-induced apoptosis. Safranal has main effect on the inhibition of metabolism and mitochondrial dysfunction. It regulates proteins considered as activator of DNA fragmentation and apoptosis mediators. Moreover, safranal regulates sialylation of glycoproteins involving in cellular adhesion, migration and survival. It suppresses cell survival and metastasis through the alteration of the sialylation level on important signaling receptors. These results highlight the impact of safranal as a potent anticancer compound on TNBCs which also can be strongly used in daily diets. SIGNIFICANCE: In first step, we evaluated the cell viability of MDA-MB-231 cell lines against the purified saffron components (total crocin, picrocrocin, crocin I and safranal). Safranal was the only compound demonstrated the anti-proliferation effect. In order to obtain an understanding of safranal cytotoxic effect on MDA-MB-231, we designed the three set of treated cell lines in 30 min, 12 h and 24 h time-points in three replicates and a combination of TMT-based labeling quantitative proteomics and titanium dioxide (TiO2)-based enrichment of sialylated N-linked glycopeptides for sialiomics analysis as a strategy to follow the more detailed mechanisms of safranal effect. The results of bioinformatics analysis revealed the multifunction role of safranal on MDA-MB-231 cell lines. Safranal mainly dysregulates mitochondrial function, inhibits metabolism and starts initial signaling of apoptosis which lead to DNA fragmentation. Moreover, safranal caused the majority of down-regulation in sialylation profile in all time-points. Safranal also declines the cell survival, adhesion and migration by dysregulation of the sialylation level in important proteins including integrins, tumor necrosis factor receptor and cell adhesion molecules (CAMs). The results provide a set of therapeutic targets for triple negative breast cancer which can help designing of effective anticancer drugs specially in targeted therapies.

Quantitative proteomic study reveals differential expression of matricellular proteins between fibrous dysplasia and cemento-ossifying fibroma pathogenesis

BACKGROUND

Fibrous dysplasia (FD) and cemento-ossifying fibroma (COF) are the most common gnathic fibro-osseous lesions. These diseases exhibit remarkable overlap of several clinicopathological aspects and differential diagnosis depends on the combination of histopathological, radiographic and clinical aspects. Their molecular landscape remain poorly characterized and herein we assessed their proteomic and phosphoproteomic profiles.

METHODS

The quantitative differences in protein profile of FD and COF were assessed by proteomic and phosphoproteomic analyses of formalin-fixed paraffin-embedded tissue samples. Pathway enrichment analyses with differentialy regulated proteins were performed.

RESULTS

FD and COF exhibited differential regulation of pathways related to extracellular matrix organization, cell adhesion, and platelet and erythrocytes activities. Additionally, these lesions demonstrated distinct abundance of proteins involved in osteoblastic differentiation and tumorigenesis and differential abundance of phosphorylation of Ser61 of Yes-associated protein 1 (YAP1).

CONCLUSIONS

In summary, despite the morphological similarity between these diseases, our results demonstrated that COF and DF present numerous quantitative differences in their proteomic profiles.These findings suggest that these fibro-osseous lesions trigger distinct molecular mechanisms during their pathogenesis. Moreover, some proteins identified in our analysis could serve as potential biomarkers for differential diagnosis of these diseases after further validation.

Linking inherent O-Linked Protein Glycosylation of YghJ to Increased Antigen Potential

Enterotoxigenic Escherichia coli (ETEC) is a WHO priority pathogen and vaccine target which causes infections in low-income and middle-income countries, travelers visiting endemic regions. The global urgent demand for an effective preventive intervention has become more pressing as ETEC strains have become increasingly multiple antibiotic resistant. However, the vaccine development pipeline has been slow to address this urgent need. To date, vaccine development has focused mainly on canonical antigens such as colonization factors and expressed toxins but due to genomic plasticity of this enteric pathogen, it has proven difficult to develop effective vaccines. In this study, we investigated the highly conserved non-canonical vaccine candidate YghJ/SsLE. Using the mass spectrometry-based method BEMAP, we demonstrate that YghJ is hyperglycosylated in ETEC and identify 54 O-linked Set/Thr residues within the 1519 amino acid primary sequence. The glycosylation sites are evenly distributed throughout the sequence and do not appear to affect the folding of the overall protein structure. Although the glycosylation sites only constitute a minor subpopulation of the available epitopes, we observed a notable difference in the immunogenicity of the glycosylated YghJ and the non-glycosylated protein variant. We can demonstrate by ELISA that serum from patients enrolled in an ETEC H10407 controlled infection study are significantly more reactive with glycosylated YghJ compared to the non-glycosylated variant. This study provides an important link between O-linked glycosylation and the relative immunogenicity of bacterial proteins and further highlights the importance of this observation in considering ETEC proteins for inclusion in future broad coverage subunit vaccine candidates.

The phosphoproteome of rice leaves responds to water and nitrogen supply

The scarcity of freshwater is an increasing concern in flood-irrigated rice, whilst excessive use of nitrogen fertilizers is costly and contributes to environmental pollution. To co-ordinate growth adaptation under prolonged exposure to limited water or excess nitrogen supply, plants employ complex systems for signalling and regulation of metabolic processes. There is limited information on the involvement of one of the most important post-translational modifications (PTMs), protein phosphorylation, in plant adaptation to long-term changes in resource supply. Oryza sativa cv. Nipponbare was grown under two regimes of nitrogen from the time of germination to final harvest. Twenty-five days after germination, water was withheld from half the pots in each nitrogen treatment and low water supply continued for an additional 26 days, while the remaining pots were well watered. Leaves from all four groups of plants were harvested after 51 days in order to test whether phosphorylation of leaf proteins responded to prior abiotic stress events. The dominant impact of these resources is exerted in leaves, where PTMs have been predicted to occur. Proteins were extracted and phosphopeptides were analysed by nanoLC-MS/MS analysis, coupled with label-free quantitation. Water and nitrogen regimes triggered extensive changes in phosphorylation of proteins involved in membrane transport, such as the aquaporin OsPIP2-6, a water channel protein. Our study reveals phosphorylation of several peptides belonging to proteins involved in RNA-processing and carbohydrate metabolism, suggesting that phosphorylation events regulate the signalling cascades that are required to optimize plant response to resource supply.

CSF proteome in multiple sclerosis subtypes related to brain lesion transcriptomes

To identify markers in the CSF of multiple sclerosis (MS) subtypes, we used a two-step proteomic approach: (i) Discovery proteomics compared 169 pooled CSF from MS subtypes and inflammatory/degenerative CNS diseases (NMO spectrum and Alzheimer disease) and healthy controls. (ii) Next, 299 proteins selected by comprehensive statistics were quantified in 170 individual CSF samples. (iii) Genes of the identified proteins were also screened among transcripts in 73 MS brain lesions compared to 25 control brains. F-test based feature selection resulted in 8 proteins differentiating the MS subtypes, and secondary progressive (SP)MS was the most different also from controls. Genes of 7 out these 8 proteins were present in MS brain lesions: GOLM was significantly differentially expressed in active, chronic active, inactive and remyelinating lesions, FRZB in active and chronic active lesions, and SELENBP1 in inactive lesions. Volcano maps of normalized proteins in the different disease groups also indicated the highest amount of altered proteins in SPMS. Apolipoprotein C-I, apolipoprotein A-II, augurin, receptor-type tyrosine-protein phosphatase gamma, and trypsin-1 were upregulated in the CSF of MS subtypes compared to controls. This CSF profile and associated brain lesion spectrum highlight non-inflammatory mechanisms in differentiating CNS diseases and MS subtypes and the uniqueness of SPMS.

Characterization of Signaling Pathways Associated with Pancreatic β-cell Adaptive Flexibility in Compensation of Obesity-linked Diabetes in db/db Mice

The onset of obesity-linked type 2 diabetes (T2D) is marked by an eventual failure in pancreatic β-cell function and mass that is no longer able to compensate for the inherent insulin resistance and increased metabolic load intrinsic to obesity. However, in a commonly used model of T2D, the db/db mouse, β-cells have an inbuilt adaptive flexibility enabling them to effectively adjust insulin production rates relative to the metabolic demand. Pancreatic β-cells from these animals have markedly reduced intracellular insulin stores, yet high rates of (pro)insulin secretion, together with a substantial increase in proinsulin biosynthesis highlighted by expanded rough endoplasmic reticulum and Golgi apparatus. However, when the metabolic overload and/or hyperglycemia is normalized, β-cells from db/db mice quickly restore their insulin stores and normalize secretory function. This demonstrates the β-cell's adaptive flexibility and indicates that therapeutic approaches applied to encourage β-cell rest are capable of restoring endogenous β-cell function. However, mechanisms that regulate β-cell adaptive flexibility are essentially unknown. To gain deeper mechanistic insight into the molecular events underlying β-cell adaptive flexibility in db/db β-cells, we conducted a combined proteomic and post-translational modification specific proteomic (PTMomics) approach on islets from db/db mice and wild-type controls (WT) with or without prior exposure to normal glucose levels. We identified differential modifications of proteins involved in redox homeostasis, protein refolding, K48-linked deubiquitination, mRNA/protein export, focal adhesion, ERK1/2 signaling, and renin-angiotensin-aldosterone signaling, as well as sialyltransferase activity, associated with β-cell adaptive flexibility. These proteins are all related to proinsulin biosynthesis and processing, maturation of insulin secretory granules, and vesicular trafficking-core pathways involved in the adaptation of insulin production to meet metabolic demand. Collectively, this study outlines a novel and comprehensive global PTMome signaling map that highlights important molecular mechanisms related to the adaptive flexibility of β-cell function, providing improved insight into disease pathogenesis of T2D.

Resolution of NASH and hepatic fibrosis by the GLP-1R/GcgR dual-agonist Cotadutide via modulating mitochondrial function and lipogenesis

Non-alcoholic fatty liver disease and steatohepatitis are highly associated with obesity and type 2 diabetes mellitus. Cotadutide, a GLP-1R/GcgR agonist, was shown to reduce blood glycemia, body weight and hepatic steatosis in patients with T2DM. Here, we demonstrate that the effects of Cotadutide to reduce body weight, food intake and improve glucose control are predominantly mediated through the GLP-1 signaling, while, its action on the liver to reduce lipid content, drive glycogen flux and improve mitochondrial turnover and function are directly mediated through Gcg signaling. This was confirmed by the identification of phosphorylation sites on key lipogenic and glucose metabolism enzymes in liver of mice treated with Cotadutide. Complementary metabolomic and transcriptomic analyses implicated lipogenic, fibrotic and inflammatory pathways, which are consistent with a unique therapeutic contribution of GcgR agonism by Cotadutide in vivo. Significantly, Cotadutide also alleviated fibrosis to a greater extent than Liraglutide or Obeticholic acid (OCA), despite adjusting dose to achieve similar weight loss in 2 preclinical mouse models of NASH. Thus Cotadutide, via direct hepatic (GcgR) and extra-hepatic (GLP-1R) effects, exerts multi-factorial improvement in liver function and is a promising therapeutic option for the treatment of steatohepatitis.

Polyamine depletion has global effects on stress and virulence gene expression and affects HilA translation in Salmonella enterica serovar typhimurium

Polyamines are small cationic amines required for modulating multiple cell process, including cell growth and DNA and RNA stability. In Salmonella polyamines are primarily synthesized from L-arginine or L-ornithine. Based on a previous study, which demonstrated that polyamines affect the expression of virulence gene in S. Typhimurium, we investigated the role of polyamines in the global gene and protein expression in S. Typhimurium. The depletion of polyamine biosynthesis led to down-regulation of genes encoding structural components of the Type Three Secretion system 1 (TTSS1) and its secreted effectors. Interestingly, Expression of HilA, which is the master regulator of Salmonella Pathogenicity Island 1 (SPI1), was only reduced at the post-transcriptional in the polyamine mutant. Enzymes related to biosynthesis and/or transport of several amino acids were up-regulated, just as the Mg²⁺-transport systems were three to six-fold up-regulated at both the transcriptional and protein levels. Furthermore, in the polyamine depletion mutant, proteins related to stress response (IbpA, Dps, SodB), were 2-5 fold up-regulated. Together our data provide strong evidence that polyamine depletion affects expression of proteins linked with virulence and stress response of S. Typhimurium. Furthermore, polyamines positively affected translation of HilA, the major regulator of SPI1.

Orthologous proteins of experimental de- and remyelination are differentially regulated in the CSF proteome of multiple sclerosis subtypes

OBJECTIVE

Here, we applied a multi-omics approach (i) to examine molecular pathways related to de- and remyelination in multiple sclerosis (MS) lesions; and (ii) to translate these findings to the CSF proteome in order to identify molecules that are differentially expressed among MS subtypes.

METHODS

To relate differentially expressed genes in MS lesions to de- and remyelination, we compared transcriptome of MS lesions to transcriptome of cuprizone (CPZ)-induced de- and remyelination. Protein products of the overlapping orthologous genes were measured within the CSF by quantitative proteomics, parallel reaction monitoring (PRM). Differentially regulated proteins were correlated with molecular markers of inflammation by using MesoScale multiplex immunoassay. Expression kinetics of differentially regulated orthologous genes and proteins were examined in the CPZ model.

RESULTS

In the demyelinated and remyelinated corpus callosum, we detected 1239 differentially expressed genes; 91 orthologues were also differentially expressed in MS lesions. Pathway analysis of these orthologues suggested that the TYROBP (DAP12)-TREM2 pathway, TNF-receptor 1, CYBA and the proteasome subunit PSMB9 were related to de- and remyelination. We designed 129 peptides representing 51 orthologous proteins, measured them by PRM in 97 individual CSF, and compared their levels between relapsing (n = 40) and progressive MS (n = 57). Four proteins were differentially regulated among relapsing and progressive MS: tyrosine protein kinase receptor UFO (UFO), TIMP-1, apolipoprotein C-II (APOC2), and beta-2-microglobulin (B2M). The orthologous genes/proteins in the mouse brain peaked during acute remyelination. UFO, TIMP-1 and B2M levels correlated inversely with inflammation in the CSF (IL-6, MCP-1/CCL2, TARC/CCL17). APOC2 showed positive correlation with IL-2, IL-16 and eotaxin-3/CCL26.

CONCLUSIONS

Pathology-based multi-omics identified four CSF markers that were differentially expressed in MS subtypes. Upregulated TIMP-1, UFO and B2M orthologues in relapsing MS were associated with reduced inflammation and reflected reparatory processes, in contrast to the upregulated orthologue APOC2 in progressive MS that reflected changes in lipid metabolism associated with increased inflammation.

HldE Is Important for Virulence Phenotypes in Enterotoxigenic Escherichia coli

Enterotoxigenic Escherichia coli (ETEC) is one of the most common causes of diarrheal illness in third world countries and it especially affects children and travelers visiting these regions. ETEC causes disease by adhering tightly to the epithelial cells in a concerted effort by adhesins, flagella, and other virulence-factors. When attached ETEC secretes toxins targeting the small intestine host-cells, which ultimately leads to osmotic diarrhea. HldE is a bifunctional protein that catalyzes the nucleotide-activated heptose precursors used in the biosynthesis of lipopolysaccharide (LPS) and in post-translational protein glycosylation. Both mechanisms have been linked to ETEC virulence: Lipopolysaccharide (LPS) is a major component of the bacterial outer membrane and is needed for transport of heat-labile toxins to the host cells, and ETEC glycoproteins have been shown to play an important role for bacterial adhesion to host epithelia. Here, we report that HldE plays an important role for ETEC virulence. Deletion of hldE resulted in markedly reduced binding to the human intestinal cells due to reduced expression of colonization factor CFA/I on the bacterial surface. Deletion of hldE also affected ETEC motility in a flagella-dependent fashion. Expression of both colonization factors and flagella was inhibited at the level of transcription. In addition, the hldE mutant displayed altered growth, increased biofilm formation and clumping in minimal growth medium. Investigation of an orthogonal LPS-deficient mutant combined with mass spectrometric analysis of protein glycosylation indicated that HldE exerts its role on ETEC virulence both through protein glycosylation and correct LPS configuration. These results place HldE as an attractive target for the development of future antimicrobial therapeutics.

Experimental Demyelination and Axonal Loss Are Reduced in MicroRNA-146a Deficient Mice

Background

The cuprizone (CPZ) model of multiple sclerosis (MS) was used to identify microRNAs (miRNAs) related to in vivo de- and remyelination. We further investigated the role of miR-146a in miR-146a-deficient (KO) mice: this miRNA is differentially expressed in MS lesions and promotes differentiation of oligodendrocyte precursor cells (OPCs) during remyelination, but its role has not been examined during demyelination.

Methods

MicroRNAs were examined by Agilent Mouse miRNA Microarray in the corpus callosum during CPZ-induced demyelination and remyelination. Demyelination, axonal loss, changes in number of oligodendrocytes, OPCs, and macrophages/microglia was compared by histology/immunohistochemistry between KO and WT mice. Differential expression of target genes and proteins of miR-146a was analyzed in the transcriptome (4 × 44K Agilent Whole Mouse Genome Microarray) and proteome (liquid chromatography tandem mass spectrometry) of CPZ-induced de- and remyelination in WT mice. Levels of proinflammatory molecules in the corpus callosum were compared in WT versus KO mice by Meso Scale Discovery multiplex protein analysis.

Results

miR-146a was increasingly upregulated during CPZ-induced de- and remyelination. The absence of miR-146a in KO mice protected against demyelination, axonal loss, body weight loss, and atrophy of thymus and spleen. The number of CNP⁺ oligodendrocytes was increased during demyelination in the miR-146a KO mice, while there was a trend of increased number of NG2⁺ OPCs in the WT mice. miR-146a target genes, SNAP25 and SMAD4, were downregulated in the proteome of demyelinating corpus callosum in WT mice. Higher levels of SNAP25 were measured by ELISA in the corpus callosum of miR-146a KO mice, but there was no difference between KO and WT mice during demyelination. Multiplex protein analysis of the corpus callosum lysate revealed upregulated TNF-RI, TNF-RII, and CCL2 in the WT mice in contrast to KO mice. The number of Mac3⁺ and Iba1⁺ macrophages/microglia was reduced in the demyelinating corpus callosum of the KO mice.

Conclusion

During demyelination, absence of miR-146a reduced inflammatory responses, demyelination, axonal loss, the number of infiltrating macrophages, and increased the number of myelinating oligodendrocytes. The number of OPCs was slightly higher in the WT mice during remyelination, indicating a complex role of miR-146a during in vivo de- and remyelination.

Development of a Neo-Epitope Specific Assay for Serological Assessment of Type VII Collagen Turnover and Its Relevance in Fibroproliferative Disorders

Type VII collagen is the main component of the anchoring fibrils connecting the basement membrane to the underlying interstitial matrix. Mutations in the type VII collagen gene cause dystrophic epidermolysis bullosa. Increased levels of type VII collagen in the skin have been reported in patients with systemic sclerosis (SSc), whereas reduced levels in the airways have been related to asthma. This indicates that type VII collagen plays an important part in upholding tissue integrity and that its remodeling may lead to pathological states. The aim of this study was to investigate the role of type VII collagen remodeling in fibroproliferative disorders. We produced monoclonal antibody targeting a specific fragment of type VII collagen (C7M) released to the systemic circulation and developed a neo-epitope specific competitive enzyme-linked immunosorbent assay (ELISA). Biological relevance was evaluated in serum from patients with SSc or chronic obstructive pulmonary disease (COPD). The C7M ELISA was technically robust and specific for the C7M neo-epitope. Serum C7M levels were significantly elevated in two cohorts of patients with SSc and in patients with COPD as compared with healthy individuals (P < 0.0001). The C7M ELISA enabled quantification of type VII collagen turnover in serum. Elevated serum C7M levels indicated that the turnover rate of type VII collagen was significantly increased in patients with SSc or COPD, suggesting a pathological role. Thus, the C7M ELISA may become useful in future investigations of type VII collagen turnover in fibroproliferative disorders, and it may prove a valuable tool for evaluating novel anti-fibrotic drugs.

Quantitative proteomics of fractionated membrane and lumen exosome proteins from isogenic metastatic and nonmetastatic bladder cancer cells reveal differential expression of EMT factors

Cancer cells secrete soluble factors and various extracellular vesicles, including exosomes, into their tissue microenvironment. The secretion of exosomes is speculated to facilitate local invasion and metastatic spread. Here, we used an in vivo metastasis model of human bladder carcinoma cell line T24 without metastatic capacity and its two isogenic derivate cell lines SLT4 and FL3, which form metastases in the lungs and liver of mice, respectively. Cultivation in CLAD1000 bioreactors rather than conventional culture flasks resulted in a 13- to 16-fold increased exosome yield and facilitated quantitative proteomics of fractionated exosomes. Exosomes from T24, SLT4, and FL3 cells were partitioned into membrane and luminal fractions and changes in protein abundance related to the gain of metastatic capacity were identified by quantitative iTRAQ proteomics. We identified several proteins linked to epithelial-mesenchymal transition, including increased abundance of vimentin and hepatoma-derived growth factor in the membrane, and casein kinase II α and annexin A2 in the lumen of exosomes, respectively, from metastatic cells. The change in exosome protein abundance correlated little, although significant for FL3 versus T24, with changes in cellular mRNA expression. Our proteomic approach may help identification of proteins in the membrane and lumen of exosomes potentially involved in the metastatic process.

MMP mediated degradation of type IV collagen alpha 1 and alpha 3 chains reflects basement membrane remodeling in experimental and clinical fibrosis--validation of two novel biomarker assays

OBJECTIVES

Fibrosis is characterized by excessive tissue remodeling resulting from altered expression of various growth factors, cytokines and proteases. We hypothesized that matrix metalloproteinase (MMP) mediated degradation of type IV collagen, a main component of the basement membrane, will release peptide fragments (neo-epitopes) into the circulation. Here we present the development of two competitive enzyme-linked immunosorbent assays (ELISAs) for assessing the levels of specific fragments of type IV collagen α1 (C4M12a1) and α3 (C4M12a3) chains in serum as indicators of fibrosis.

METHODS

Fragments of type IV collagen cleaved in vitro by MMP-12 were identified by mass spectrometry, and two were chosen for ELISA development due to their unique sequences. The assays were evaluated using samples from a carbon tetrachloride (CCl₄) rat model of liver fibrosis and from patients with idiopathic pulmonary fibrosis (IPF) or chronic obstructive pulmonary disease (COPD).

RESULTS

Two technically robust ELISAs were produced using neo-epitope specific monoclonal antibodies. Mean serum C4M12a1 levels were significantly elevated in CCl₄-treated rats compared with controls in weeks 12, 16, and 20, with a maximum increase of 102% at week 16 (p < 0.0001). Further, C4M12a1 levels correlated with the total collagen content of the liver in CCl₄-treated rats (r = 0.43, p = 0.003). Mean serum C4M12a3 levels were significantly elevated in patients with mild, moderate, and severe IPF, and COPD relative to healthy controls, with a maximum increase of 321% in COPD (p < 0.0001).

CONCLUSIONS

Two assays measuring C4M12a1 and C4M12a3 enabled quantification of MMP mediated degradation of type IV collagen in serum. C4M12a1 was elevated in a pre-clinical model of liver fibrosis, and C4M12a3 was elevated in IPF and COPD patients. This suggests the use of these assays to investigate pathological remodeling of the basement membrane in different organs. However, validations in larger clinical settings are needed.

Acute Myocardial Infarction and Pulmonary Diseases Result in Two Different Degradation Profiles of Elastin as Quantified by Two Novel ELISAs

BACKGROUND

Elastin is a signature protein of the arteries and lungs, thus it was hypothesized that elastin is subject to enzymatic degradation during cardiovascular and pulmonary diseases. The aim was to investigate if different fragments of the same protein entail different information associated to two different diseases and if these fragments have the potential of being diagnostic biomarkers.

METHODS

Monoclonal antibodies were raised against an identified fragment (the ELM-2 neoepitope) generated at the amino acid position '552 in elastin by matrix metalloproteinase (MMP) -9/-12. A newly identified ELM neoepitope was generated by the same proteases but at amino acid position '441. The distribution of ELM-2 and ELM, in human arterial plaques and fibrotic lung tissues were investigated by immunohistochemistry. A competitive ELISA for ELM-2 was developed. The clinical relevance of the ELM and ELM-2 ELISAs was evaluated in patients with acute myocardial infarction (AMI), no AMI, high coronary calcium, or low coronary calcium. The serological release of ELM-2 in patients with chronic obstructive pulmonary disease (COPD) or idiopathic pulmonary fibrosis (IPF) was compared to controls.

RESULTS

ELM and ELM-2 neoepitopes were both localized in diseased carotid arteries and fibrotic lungs. In the cardiovascular cohort, ELM-2 levels were 66% higher in serum from AMI patients compared to patients with no AMI (p<0.01). Levels of ELM were not significantly increased in these patients and no correlation was observed between ELM-2 and ELM. ELM-2 was not elevated in the COPD and IPF patients and was not correlated to ELM. ELM was shown to be correlated with smoking habits (p<0.01).

CONCLUSIONS

The ELM-2 neoepitope was related to AMI whereas the ELM neoepitope was related to pulmonary diseases. These results indicate that elastin neoepitopes generated by the same proteases but at different amino acid sites provide different tissue-related information depending on the disease in question.

Biglycan fragmentation in pathologies associated with extracellular matrix remodeling by matrix metalloproteinases

Background

The proteoglycan biglycan (BGN) is involved in collagen fibril assembly and its fragmentation is likely to be associated with collagen turnover during the pathogenesis of diseases which involve dysregulated extracellular matrix remodeling (ECMR), such as rheumatoid arthritis (RA) and liver fibrosis. The scope of the present study was to develop a novel enzyme-linked immunosorbent assay (ELISA) for the measurement of a MMP-9 and MMP-12-generated biglycan neo-epitope and to test its biological validity in a rat model of RA and in two rat models of liver fibrosis, chosen as models of ECMR.

Results

Biglycan was cleaved in vitro by MMP-9 and -12 and the 344^′YWEVQPATFR^′353 peptide (BGM) was chosen as a potential neo-epitope. A technically sound competitive ELISA for the measurement of BGM was generated and the assay was validated in a bovine cartilage explant culture (BEX), in a collagen induced model of rheumatoid arthritis (CIA) and in two different rat models of liver fibrosis: the carbon tetrachloride (CCL4)-induced fibrosis model, and the bile duct ligation (BDL) model. Significant elevation in serum BGM was found in CIA rats compared to controls, in rats treated with CCL4 for 16 weeks and 20 weeks compared to the control groups as well as in all groups of rats subject to BDL compared with sham operated groups. Furthermore, there was a significant correlation of serum BGM levels with the extent of liver fibrosis determined by the Sirius red staining of liver sections in the CCL4 model.

Conclusion

We demonstrated that the specific tissue remodeling product of MMPs-degraded biglycan, namely the neo-epitope BGM, is correlated with pathological ECMR. This assay represents both a novel marker of ECM turnover and a potential new tool to elucidate biglycan role during the pathological processes associated with ECMR.

Not only accumulation, but also saturation status of intramuscular lipids is significantly affected by PPARγ activation

AIM

Intramuscular lipid accumulation has been associated with insulin resistance, and after thiazolidinediones (TZD) treatment, it was shown to be reduced in some, but not all, studies. This work was undertaken to investigate the relationships between intramuscular lipids [free fatty acids (FFA), diacylglycerols (DAG), triacylglycerol (TAG) and phospholipids] and plasmalemmal expression of fatty acid (FA) transporter [FAT/CD36 and FABPpm] in the muscles of varying oxidative capacity, after peroxisome proliferator-activated receptors gamma (PPARγ) activation (rosiglitazone) in an animal model of high-fat-diet-induced insulin resistance. Endurance training was also included to further explore the differences in these relationships.

METHODS

We have used gas liquid chromatography to estimate FA content and composition in each lipid fraction. For sarcolemmal expression of FA transporters, subfractionation of skeletal muscles with subsequent western blot technique was applied.

RESULTS

High-fat diet induced intramuscular accumulation of FFA, DAG and TAG, irrespective of muscle's fibre composition. PPARγ activation (rosiglitazone) and, to a lesser extent, endurance training further increased TAG accumulation, while it reduced DAG in oxidative muscles (soleus and red gastrocnemius). Aforementioned interventions increased also sarcolemmal FAT/CD36 and FABPpm expressions in particular muscles. Irrespective of diet, rosiglitazone and exercise decreased significantly FA saturation status favouring proportionate enhancement in monounsaturated FA (rosiglitazone) or polyunsaturated FAs (endurance training).

CONCLUSION

These findings support the conclusion that not only the change in total lipid content (DAG and TAG), but also FA composition is affected by rosiglitazone in an animal model of high-fat-diet-induced insulin resistance.

Investigation of two novel biochemical markers of inflammation, matrix metalloproteinase and cathepsin generated fragments of C-reactive protein, in patients with ankylosing spondylitis

OBJECTIVES

Ankylosing spondylitis (AS) is a chronic inflammation of the spine and the sacroiliac joints. Current markers of inflammation, such as C-reactive protein (CRP), are reflecting the production of an acute phase reactant rather than tissue specific inflammation, but the use of CRP as a diagnostic and prognostic marker for AS has not provided the sought accuracy and specificity. We hypothesized that local enzymatic activity in the disease-affected tissue, which is associated with extensive tissue turnover may, by cleavage, modify the CRP produced in the liver. These cleavage products may provide additional information on systemic inflammation as compared to that of full-length CRP. We investigated whether these CRP degradation products would provide additional diagnostic value in AS patients compared to full-length CRP.

METHODS

CRP fragments were identified by mass-spectrometry. Two fragments were selected for ELISA development. One assay exclusively identified a matrix metalloproteinase (MMP) generated fragment, CRP-MMP, whereas the other assay identified a cathepsin generated fragment, CRP-CAT. Full-length CRP, CRP-MMP and CRP-CAT were measured in serum samples from 40 AS patients and 40 sex- and age-matched controls.

RESULTS

Full-length CRP was not elevated in AS patients compared to controls, whereas CRP-MMP was elevated by 25% (p<0.001) and CRP-CAT by 50% (p<0.0001). The Area Under Curve of the Receiver-Operator Characteristic curve of CRP-CAT was the highest with 77%.

CONCLUSIONS

MMP and cathepsin degraded CRP provided more discriminative diagnostic potential compared to that of full-length CRP in this current study. These data suggest that different pools of CRP may provide insight into the inflammation processes in AS.

MMP mediated type V collagen degradation (C5M) is elevated in ankylosing spondylitis

OBJECTIVES

Type V collagen has been demonstrated to control fibril formation. The aim of this study was to develop an ELISA capable of detecting a fragment of type V collagen generated by MMP-2/9 and to evaluate the assay as biomarker for ankylosing spondylitis (AS).

DESIGN AND METHODS

A fragment unique to type V collagen and generated by both MMP-2/9 cleaved at the amino acid position 1317 (C5M) was selected for ELISA development. 40 AS patients and 40 age-matched controls were evaluated.

RESULTS

An ELISA detecting C5M with inter- and intra-assay variations of 9.1% and 4.4% was developed. C5M levels were significantly higher in AS patients compared to controls, 229% (p<0.0001). The diagnostic AUC was 83%.

CONCLUSIONS

This ELISA is the first for detecting type V collagen degradation. AS patients had highly elevated levels of MMP mediated type V collagen degradation. The prognostic and diagnostic values need to be further investigated in additional clinical settings.

The influence of the fungal pathogen Mycocentrospora acerina on the proteome and polyacetylenes and 6-methoxymellein in organic and conventionally cultivated carrots (Daucus carota) during post harvest storage

Many carrots are discarded during post harvest cold storage due to development of fungal infections, caused by, e.g., Mycocentrospora acerina (liquorice rot). We compared the susceptibility of carrots grown under conventional and organic agricultural practices. In one year, organically cultivated carrots showed 3× to 7× more symptoms than conventionally cultivated, when studying naturally occurring disease at 4 and 6 months, respectively. On the other hand, we have developed a bioassay for infection studies of M. acerina on carrots and observed that organic roots were more susceptible after one month of storage than conventional ones, but no differences were apparent after four or six months storage. Levels of polyacetylenes (falcarinol, falcarindiol and falcarindiol-3-acetate) did not change, whereas the isocoumarin phytoalexin (6-methoxymellein) accumulated in infected tissue as well as in healthy tissue opposite the infection. The proteomes of carrot and M. acerina were characterized, the intensity of 33 plant protein spots was significantly changed in infected roots including up regulation of defence and stress response proteins but also a decrease of proteins involved in energy metabolism. This combined metabolic and proteomic study indicates that roots respond to fungal infection through altered metabolism: simultaneous induction of 6-methoxymellein and synthesis of defence related proteins.

Assessment of proteolytic degradation of the basement membrane: a fragment of type IV collagen as a biochemical marker for liver fibrosis

BACKGROUND

Collagen deposition and an altered matrix metalloproteinase (MMP) expression profile are hallmarks of fibrosis. Type IV collagen is the most abundant structural basement membrane component of tissue, which increases 14-fold during fibrogenesis in the liver. Proteolytic degradation of collagens by proteases produces small fragments, so-called neoepitopes, which are released systemically. Technologies investigating MMP-generated fragments of collagens may provide more useful information than traditional serological assays that crudely measure total protein. In the present study, we developed an ELISA for the quantification of a neoepitope generated by MMP degradation of type IV collagen and evaluated the association of this neoepitope with liver fibrosis in two animal models.

METHODS

Type IV collagen was degraded in vitro by a variety of proteases. Mass spectrometric analysis revealed more than 200 different degradation fragments. A specific peptide sequence, 1438'GTPSVDHGFL'1447 (CO4-MMP), in the α1 chain of type IV collagen generated by MMP-9 was selected for ELISA development. ELISA was used to determine serum levels of the CO4-MMP neoepitope in two rat models of liver fibrosis: inhalation of carbon tetrachloride (CCl4) and bile duct ligation (BDL). The levels were correlated to histological findings using Sirius red staining.

RESULTS

A technically robust assay was produced that is specific to the type IV degradation fragment, GTPSVDHGFL. CO4-MMP serum levels increased significantly in all BDL groups compared to baseline, with a maximum increase of 248% seen two weeks after BDL. There were no changes in CO4-MMP levels in sham-operated rats. In the CCl4 model, levels of CO4-MMP were significantly elevated at weeks 12, 16 and 20 compared to baseline levels, with a maximum increase of 88% after 20 weeks. CO4-MMP levels correlated to Sirius red staining results.

CONCLUSION

This ELISA is the first assay developed for assessment of proteolytic degraded type IV collagen, which, by enabling quantification of basement membrane degradation, could be relevant in investigating various fibrogenic pathologies. The CO4-MMP degradation fragment was highly associated with liver fibrosis in the two animal models studied.

MMP mediated degradation of type VI collagen is highly associated with liver fibrosis--identification and validation of a novel biochemical marker assay

Background and Aims

During fibrogenesis, in which excessive remodeling of the extracellular matrix occurs, both the quantity of type VI collagen and levels of matrix metalloproteinases, including MMP-2 and MMP-9, increase significantly. Proteolytic degradation of type VI collagen into small fragments, so-called neo-epitopes, may be specific biochemical marker of liver fibrosis. The aim of this study was to develop an ELISA detecting a fragment of type VI collagen generated by MMP-2 and MMP-9, and evaluate this assay in two preclinical models of liver fibrosis.

Methods

Mass spectrometric analysis of cleaved type VI collagen revealed a large number of protease-generated neo-epitopes. A fragment unique to type VI collagen generated by MMP-2 and MMP-9 was selected for ELISA development. The CO6-MMP assay was evaluated in two rat models of liver fibrosis: bile duct ligation (BDL) and carbon tetrachloride (CCl4)-treated rats.

Results

Intra- and inter-assay variation was 4.1% and 10.1% respectively. CO6-MMP levels were significantly elevated in CCl₄-treated rats compared to vehicle-treated rats at weeks 12 (mean 30.9 ng/mL vs. 12.8 ng/mL, p = 0.002); week 16 (mean 34.0 ng/mL vs. 13.7 ng/mL, p = 0.0018); and week 20 (mean 35.3 ng/mL vs. 13.3 ng/mL, p = 0.0033) with a tight correlation between hepatic collagen content and serum levels of CO6-MMP (R² = 0.58, p<0.0001) in CCl₄- treated rats. In BDL rats, serum levels of CO6-MMP were significantly elevated compared to the levels in sham-operated animals both at 2 weeks (mean 29.5 ng/mL vs. 14.2 ng/mL, p = 0.0001) and 4 weeks (mean 33.0 ng/mLvs. 11.8 ng/mL, p = 0.0003).

Conclusions

This novel ELISA is the first assay enabling assessment of MMP degraded type VI collagen, allowing quantification of type VI collagen degradation, which would be relevant for different pathologies. The marker was highly associated with liver fibrosis in two liver fibrosis animal models, suggesting type VI turnover to be a central player in fibrogenesis.

Effect of plasma free fatty acid concentration on the content and composition of the free fatty acid fraction in rat skeletal muscles

Skeletal muscles contain a fraction of free (unesterified) fatty acids. This fraction is very small, but important since it contributes to the creation of the plasma-myocyte free fatty acid concentration gradient. Maintenance of this gradient is necessary for blood-borne fatty acids to be transported into the cell. There are no data on the regulation of the content and composition of the free fatty acid fraction in the cell. The aim of the present study was to examine the effect of an elevation and a reduction in the plasma-borne free fatty acid concentration on the content and composition of the free fatty acid fraction in different skeletal muscle types. The experiments were carried out on male Wistar rats with 280 - 310 g body weight. They were divided into four groups - 1, control; 2, exercised 3 h on a treadmill moving with a speed of 1,200 m/h and set at + 10 degrees incline; 3, treated with heparin; and 4, treated with nicotinic acid. Samples of the soleus as well as the red and white sections of the gastrocnemius muscles were taken. These muscles are composed mostly of slow-twitch oxidative, fast-twitch oxidative-glycolytic and fast-twitch glycolytic fibres, respectively. Lipids were extracted from the muscle samples and from the blood; the free fatty acid fraction was isolated by means of thin-layer chromatography. The individual free fatty acids were identified and quantified using gas-liquid chromatography. The plasma concentration of free fatty acids was as follows: control group, 236.1 +/- 32.9; after exercise, 407.4 +/- 117.5; after heparin, 400.8 +/- 36.8; and after nicotinic acid, 102.5 +/- 26.1 micromol/l (p < 0.01 vs. control values in each case). The total content of the free fatty acid fraction in the control group was as follows: white gastrocnemius, 27.6 +/- 7.3; red gastrocnemius, 52.2 +/- 13.9; soleus, 72.3 +/- 10.2 nmol/g. Elevation in plasma free acid concentration during exercise increased the total content of free fatty acids in the white gastrocnemius (38.7 +/- 13.9) and in the soleus (103.4 +/- 15.9 nmol/g; rest-exercise: p < 0.05 and p < 0.01, respectively), but had no effect in the red gastrocnemius. Neither elevation in the plasma free fatty acid concentration with heparin nor reduction with nicotinic acid affected the total content of the free fatty acid fraction in the muscles examined. The ratio of plasma concentration of individual acid to muscle concentration for the same acid varied greatly, depending on acid, muscle type and experimental group. The ratio was positive (above unity) for each acid almost in all cases with the exception of certain acids in the nicotinic acid-treated group where it was below unity. We conclude that the skeletal myocytes maintain a stable level of free fatty acid fraction in the wide range of plasma free fatty acid concentrations.

The effects of transcription regulating genes PDR1, pdr1-3 and PDR3 in pleiotropic drug resistance

Mutations in the yeast PDR1 or PDR3 genes lead to acquisition of resistance towards various unrelated cytotoxic compounds. The broad range and different properties of these compounds indicate the existence of mechanisms which protect cellular targets, neutralise or expel the compounds from the cell. In wild type and pdr mutants, 83 proteins, out of 2706 detected by two-dimensional gel electrophoresis, were differentially expressed. Fifty-three of these could be identified by mass spectrometry. The functions of these 53 proteins fall into several metabolic groups demonstrating that drug resistance phenotype is a mosaic response derived from such diverse functions as stress defence, endocytosis, oxidation and reduction, amino acid synthesis and mitochondrial biogenesis. The patterns of synthesis of the selected proteins clearly demonstrates the complex interaction between Pdr1p and Pdr3p in exerting their regulatory functions. The data also indicate that, in the Saccharomyces cerevisiae pleiotropic drug resistance phenomenon, translational events exert a more decisive effect than transcription in regulating the levels of active forms of the proteins involved.

Conception of the cervico-brachial protector for motorcycle drivers

The increasing popularity of motorcycles increases the role of motorcycle accidents as a main cause of brachial plexus injuries. In view of the high social cost of treatment of the victims it seemed desirable to devise some kind of protective clothing for motorcyclists. The protective clothing devised by teams from Department of Neurosurgery, TRICOTEXTIL--and Aeronautics and Applied Mechanics Institute, consists of the following parts: cervical collar--acting against force causing lateral bending and extension of cervical spine, shock-absorptive shoulder pads--acting against the impact energy partially absorbing it and partially transmitting to the dorsal stiff bar, dorsal stiff bar and sacroiliac belt--partially immobilizes the thoracic and lumbar spine, acts against its compression, transmits the impact energy to the iliac crests and hips. The expected biomechanical effects of the cervico-brachial protector are as follows: In brachial region it should diminish the impact energy by its partial absorption and partial transmission along dorsal stiff bar to sacroiliac belt. It should act against excessive cervical spine motion--mainly against lateral bending and extension. It should act against excessive depression of the shoulder. The protective system built in the jacket should co-operate with the helmet of motorcycle driver. It should be comfortable for the driver and conform to security standards. Prototype of the protector underwent kinetic sledge tests in Industrial Motorization Institute (PIMOT), Warsaw, with the use of Hybrid Dummy II.

Proteome analysis of interleukin-1beta--induced changes in protein expression in rat islets of Langerhans

The intracellular molecular events involved in the beta-cell death process are complex but poorly understood. Cytokines, e.g., interleukin (IL)-1beta, may play a crucial role in inducing this process. Protein synthesis is necessary for the deleterious effect of IL-1, and induction of both protective and deleterious proteins has been described. To characterize the rather complex pattern of islet protein expression in rat islets in response to IL-1, we have attempted to identify proteins of altered expression level after IL-1 exposure by 2D gel electrophoresis and mass spectrometry. Of 105 significantly changed (i.e., up- or downregulated or de novo-induced) protein spots, we obtained positive protein identification for 60 protein spots. The 60 identifications corresponded to 57 different proteins. Of these, 10 proteins were present in two to four spots, suggesting that posttranslatory modifications had occurred. In addition, 11 spots contained more than one protein. The proteins could be classified according to their function into the following groups: 1) energy transduction; 2) glycolytic pathway; 3) protein synthesis, chaperones, and protein folding; and 4) signal transduction, regulation, differentiation, and apoptosis. In conclusion, valuable information about the molecular mechanisms involved in cytokine-mediated beta-cell destruction was obtained by this approach.

Islet protein expression changes during diabetes development in islet syngrafts in BB-DP rats and during rejection of BB-DP islet allografts

Interleukin 1beta (IL-1) is cytotoxic to rat pancreatic beta-cells in vitro, and increased expression of IL-1 mRNA is found in the islets of Langerhans during development of diabetes in BB/Wor/Mol-BB2 (BB-DP) rats and NOD mice. It has been proposed that IL-1 induces a race between protective and deleterious proteins in the beta-cells during development of diabetes, and that heat shock proteins 70 and 90, and manganese superoxide dismutase, all inducible by IL-1 are potentially protective proteins. We have established a database of approximately 2000 neonatal rat-islet proteins by two-dimensional gel (2-D gel) electrophoresis of [35S]-methionine labelled neonatal Wistar Furth rat islets. In these IL-1 was shown to up- or down-regulate the islet-expression level of 99, and to induce de novo synthesis of 6 proteins. The identity of most of the IL-1 induced proteins is unknown and under study. In this study we wished to investigate if changes in protein expression induced in vitro by IL-1 stimulation of islets are also seen in vivo during spontaneous development of diabetes in BB-DP rats, and during islet allograft rejection. Two-hundred neonatal BB-DP rat islets were grafted under the kidney capsule of either 30-day-old BB-DP rats killed at onset of diabetes or of 30-day-old Wistar Kyoto (WK) rats, killed 12 days after grafting. Proteins in excised islet-grafts and in vitro IL-1 exposed isolated neonatal BB-DP rat islets were labelled with [35S]-methionine, and processed for 2-D gel electrophoresis. Fluorographs of the gels were analysed by computer. A total of 1815 proteins were found in 3 of 3 12.5% polyacrylamide gels. Interleukin-1 was found to change expression level of 82 of these proteins (22 up- and 60 down-regulated) in neonatal BB-DP rat islets in vitro. Of these 82 proteins 33 (4 up- and 29 down-regulated) also changed level of expression during disease occurrence in syngeneic islet grafts from diabetic BB-DP rats, and 29 (4 up- and 25 down-regulated) during rejection of BB-DP islets grafted to WK rats. Changes in the expression level of 14 (3 up- and 11 down-regulated) of the 82 proteins altered by IL-1 in vitro were only found in syngeneic islet grafts in diabetic BB-DP rats, and changes in the expression level of 8 (2 up- and 6 down-regulated) of these 82 proteins expression were only found in BB-DP islet allografts in WK recipients. Identification of these proteins may be important in understanding the mechanisms of islet destruction during development of insulin-dependent diabetes mellitus and during islet allograft rejection.

Effect of sex and bezafibrate on incorporation of blood borne palmitate into lipids of rat liver nuclei

The aim of the present study was to investigate whether lipid metabolism in the nuclei is affected by changes in the metabolism of free fatty acids in the liver. The experiments were carried out on 3 groups of rats: 1 - control-male, 2 - female, and 3 - male, treated with bezafibrate (a peroxisome proliferator). The rats received 14C-palmitic acid intravenously. Thirty min later liver samples and blood from the abdominal aorta were taken. The liver nuclei were isolated in sucrose gradient. Lipids were extracted from the nuclei and the liver homogenate and subsequently separated into the following fractions: phospholipids, mono, di- and triacylglycerols, free fatty acids, cholesterol and cholesterol esters. The radioactivity of each fraction was counted. Furthermore, the content of free fatty acids and the fatty acid binding proteins was measured. It was found that radioactivity was present in each lipid fraction obtained from the liver homogenate and from the nuclei. In the female group, the total radioactivity of lipids in the liver homogenate was lower, whereas in the nuclei it was higher in comparison to the male group. The reduction in the radioactivity in the liver was mostly accounted for by decreased radioactivity in the fraction oftriacylglycerols and phospholipids. In the nuclei, the radioactivity of the fraction of phospholipids, free fatty acids and diacylglycerols was elevated. Bezafibrate did not affect the total radioactivity of lipids in the liver and reduced it in the nuclei. In the liver, the drug increased radioactivity mostly in the fraction of phospholipids and reduced it mainly in the fraction of triacylglycerols. In the nuclei, the radioactivity of each lipid fraction examined was reduced. The content of the fraction of free fatty acids in the liver and in the nuclei in the female and in the bezafibrate-treated groups did not differ from the respective value in the control group. The content of fatty acid binding proteins in the nuclei of the female and bezafibrate-treated groups increased in parallel to the elevation in their content in the cytosol. It is concluded that the female sex hormones and bezafibrate influence the transport of selected lipids into the nuclei. The effects seem to be a consequence of the action of these factors directly on the nucleus.

Effect of streptozotocin diabetes on fatty acid content and composition of the heart lipids in the rat

The aim of the present study was to examine the effect of diabetes on long chain fatty acid content and composition in the heart lipids. The experiments were carried out on male Wistar rats. Diabetes was induced by intravenous administration of streptozotocin. Samples of the blood and the left ventricle were taken. Lipids were extracted and separated into different fractions. The following fractions were examined: free fatty acids, diacylglycerols, triacylglycerols and phospholipids. The fatty acids from each fraction were identified and quantified by means of gas-liquid chromatography. It was found that diabetes resulted in an almost four-fold elevation in the content of the free fatty acid fraction in the heart, whereas the plasma concentration of free fatty acids increased only two-fold. The diabetes induced changes in the content of particular acids in the fraction of free fatty acid in the heart did not reflect changes in their concentration in the plasma. The content of total di- and triacylglycerol fatty acids also markedly increased in diabetes. In both the compounds, the elevation in the content of individual acids, with the exception of myristic and palmitoleic acid reflected roughly the elevation in their concentration in the plasma. There were, however, several differences in the percentage composition of fatty acids between the two groups. In the fraction of phospholipids, the content of myristic, palmitic, stearic and linoleic acids remained stable, whilst the content of palmitoleic acid was reduced and the content of arachidonic acid was elevated. It is concluded that insulin deficiency results in marked changes in the endogenous lipid fatty acid content of the heart. These changes are not directly related to alterations in the supply of individual acids through the plasma.

Composition of phospholipid fatty acids in erythrocyte membranes of children with chronic juvenile arthritis: clinical and biochemical correlations

Systemic diseases of connective tissue, including chronic juvenile arthritis are associated with a number of metabolic disorders such as e.g. lipid disturbances. The purpose of the present work was to analyse the composition of fatty acids in erythrocyte phospholipids of children with juvenile chronic arthritis and to determine a correlation between the composition of these acids and patients' clinical status. The study was conducted on 47 children with juvenile chronic arthritis (jca) and 29 healthy subjects. The following fractions of phospholipids were obtained with the help of thin-layer chromatography: phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidyloinositol, cardiolipin, sphingolipin. Fatty acids were analysed with the use of gas chromatograph (Hewlett-Packard 5890). Saturated fatty acids as well as mono- and polyunsaturated (n-3 and n-6) fatty acids were identified. The decrease in the percentage of linolenic acid, PUFA n-6 and PUFA n-3 was found in all the phospholipid fractions in children with jca when compared with control group. There was a concurrent increase in saturated fatty acids, mainly stearic and palmitic acids. The differences in the distribution of fatty acids in erythrocyte phospholipids were observed at early stage of the disease and they became more conspicuous as inflammatory process proceeded.

Comparison of yeast cell protein solubilization procedures for two-dimensional electrophoresis

Three different procedures for the solubilization of yeast (S. cerevisiae) cell proteins were compared on the basis of the obtained two-dimensional (2-D) polypeptide patterns. Major emphasis was laid on minimizing handling steps, protein modification or degradation, and quantitative loss of high molecular mass proteins. The procedures employed were sonication, followed by (i) protein solubilization with "standard" lysis buffer (9 M urea, 2% 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS), 1% dithiothreitol (DTT), 2% v/v carrier ampholytes, (ii) presolubilization of proteins with sodium dodecyl sulfate (SDS) buffer, consisting of 1% SDS and 100 mM tris(hydroxymethyl)aminomethane (Tris)-HCl, pH 7.0, followed by dilution with "standard" lysis buffer, and (iii) boiling the sample with SDS during cell lysis, followed by dilution with thiourea/urea lysis buffer (2 M thiourea/ 7 M urea, 4% w/v CHAPS, 1% w/v DTT, 2% v/v carrier ampholytes). All procedures tested were rapid and simple. However, with the first procedure (i), considerable degradation of high Mr proteins occurred. In contrast, protein degradation was minimized by boiling the sample in SDS buffer immediately after sonication (method ii). Protein disaggregation and solubilization of high Mr proteins were further improved by pre-boiling with SDS and using thiourea/urea lysis buffer instead of "standard" lysis buffer (procedure iii).

Effect of acute streptozotocin diabetes on fatty acid content and composition in different lipid fractions of rat skeletal muscle

The aim of the present study was to examine the effect of acute streptozotocin diabetes on long chain fatty acid content and composition in different lipid classes of particular muscle types in the rat. Two days after streptozotocin administration, rats were anesthetised, and the white and red sections of the gastrocnemius, the soleus and the blood were taken. Lipids were extracted with chloroform/methanol and separated into different fractions (phospholipids, free fatty acids, di- and triacylglycerols) by means of thin layer chromatography. Fatty acids of each fraction were identified and quantified by means of gas-liquid chromatography. The diabetes resulted in elevation of the concentration of blood glucose (over four-fold) and the plasma free fatty acid (over two-fold). Total free fatty acid content in the muscles of diabetic rats increased by 26% in the white, 24% in the red gastrocnemius and 21% in the soleus. There were also changes in the composition of that fraction in each muscle. Diacylglycerol fatty acid content was elevated in both parts of the gastrocnemius (the white part by 15%, the red part by 44%) and remained stable in the soleus of the diabetic rats. The content of triacylglycerol fatty acids was elevated only in the red gastrocnemius in the diabetic group (by 112%), but changes in fatty acid composition in this fraction occurred in each muscle. The content of phospholipid fatty acids was elevated in the white gastrocnemius (by 13%) and remained stable in other muscles. There were only minor changes in phospholipid fatty acid composition in the diabetic rats. We concluded that acute insulin deficiency changes fatty acid content and composition in skeletal muscle lipids. The changes depend both on lipid fraction and muscle type.

Correlation of acidic and basic carrier ampholyte and immobilized pH gradient two-dimensional gel electrophoresis patterns based on mass spectrometric protein identification

Separation of proteins on either carrier ampholyte-based or immobilized pH gradient-based two-dimensional (2-D) gels gives rise to electrophoretic patterns that are difficult to compare visually. In this paper we have used matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) to determine the identities of 335 protein spots in these two 2-D gel systems, including a substantial number of basic proteins which had never been identified before. Proteins that were identified in both gel systems allowed us to cross-reference the gel patterns. Vector analysis of these cross-references demonstrated that there is no obvious pattern by which the mobility of a protein in one gel system can be used to predict its mobility in the other. Thus, as laboratories adopt the immobilized pH gradient-based 2-D gel systems, the only reliable means of translating the data gained with the carrier ampholyte-based gel system is to positively identify the proteins in both 2-D systems.

Down-regulation of hepatic and renal 11 beta-hydroxysteroid dehydrogenase in rats with liver cirrhosis

BACKGROUND & AIMS

11 beta-Hydroxysteroid dehydrogenase (11 beta-OHSD) enzymes are responsible for the interconversion of active 11 beta-hydroxycorticosteroids into inactive 11-ketoglucocorticosteroids and by that mechanism regulate the intracellular access of the steroids to the cognate receptor. A down-regulation of the shuttle of active to inactive glucocorticoids enhances access of glucocorticosteroids to both the glucocorticoid and the mineralocorticoid receptors. In liver cirrhosis, enhanced mineralocorticoid and glucocorticoid effects are observed. We therefore investigated the impact of liver cirrhosis after bile duct ligation on the transcription and activity of 11 beta-OHSD1 and 11 beta-OHSD2 in the corresponding tissues.

METHODS

Messenger RNA from 11 beta-OHSD1 and 11 beta-OHSD2 was assessed by reverse-transcription polymerase chain reaction; activity was assessed by measuring the interconversion of corticosterone to dehydrocorticosterone. The effect of bile and bile salts was determined using COS-1 cells transfected with 11 beta-OHSD1 or 11 beta-OHSD2.

RESULTS

In liver tissue, the messenger RNA ratios of 11 beta-OHSD1 to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) levels and, in kidney tissue, the ratios of 11 beta-OHSD2 to GAPDH levels decreased after induction of liver cirrhosis. The 11 beta-OHSD activities were correspondingly reduced. Bile and individual bile salts inhibited 11 beta-OHSD1 and 11 beta-OHSD2 oxidative activity in transfected COS-1 cells.

CONCLUSIONS

These findings indicate that in liver cirrhosis the mineralocorticoid and glucocorticoid receptor-protecting effects by the 11 beta-OHSD isoenzymes are down-regulated and that by the same mechanism the glucocorticoid and mineralocorticoid effects are enhanced.

Stimulation of migration and wound repair of guinea-pig airway epithelial cells in response to epidermal growth factor

Repair of the airway epithelium after injury involves cell proliferation, migration, and spreading into the injury site. The growth factor, epidermal growth factor (EGF), elicits proliferation of many epithelial cell types in vitro and in vivo, including airways epithelium. However, its effects on cell migration and spreading are less clear. We studied the effects of EGF on guinea-pig tracheal epithelial cell (GPTEC) chemotaxis and migration during wound repair. Primary GPTEC were allowed to migrate through a gelatin-coated filter for 6 h in a chemotaxis chamber, after which the number of migrated cells were counted. EGF elicited migration of GPTEC that was substantial and concentration-dependent. Treatment with EGF accelerated closure of small wounds in confluent epithelial monolayers substantially as measured by video microscopy over 24 h. These effects of EGF were concentration-dependent and seen in monolayer wounds of different size. Effects of EGF did not depend on the underlying matrix on which cells were grown; cells grown on laminin, fibronectin, or collagen had similar wound closure velocities in response to EGF. Early effects of EGF on wound closure were not due to cell proliferation at the wound edge. These data demonstrate that EGF elicits both chemotaxis and migration of airway epithelial cells in culture.

Characterization of free and glyceride-esterified long chain fatty acids in different skeletal muscle types of the rat

The plasma-borne long-chain free fatty acids (FFA) enter skeletal muscle cells. Upon entering they are oxidized or esterified and a fraction remains free (non-esterified). The data on free fatty acids in skeletal muscles remain highly controversial. Furthermore, the composition of individual fatty acids in various lipid fractions including free fatty acids, monoglyceride and diglyceride in muscles has not been characterized. Also data on the composition of fatty acids esterified into muscle triglycerides and phospholipids are incomplete. The present study was undertaken to examine a composition of fatty acids in lipid fractions of different skeletal muscle types. For this purpose, samples of the rat soleus, red and white portions of gastrocnemius were excised, trimmed of visible fat and fascias and immediately frozen in liquid nitrogen. Samples were then pulverized and, lipids were extracted and fractionated by thin-layer chromatography. Individual long-chain fatty acids in different fractions were identified, characterized and quantitated by gas-liquid chromatography. FFA composition in the plasma was also determined. The total FFA content in the soleus, red and white gastrocnemius was 69.1 +/- 10.8, 49.0 +/- 13.6 and 22.7 +/- 8.6 nmol/g, respectively. Palmitic and oleic acids were the major fatty acids in the muscles FFA fraction. Monoglyceride fraction of each muscle contained palmitic, stearic and linoleic acid as the major fatty acids, Diglyceride fraction contained mostly palmitic and oleic acid whereas triglyceride fraction mostly palmitic and linoleic acid.. The fraction of phospholipids was composed mostly of palmitic and linoleic acid but contained also considerable percentage of archidonic acid. Total plasma FFA/muscle FFA ratio depended on a muscle type and was: 2.4 in the soleus, 3.5 in the red and 7.4 in the white gastrocnemius. This assured transport of FFA to the myocytes. However, there were great differences in the ratio between particular FFA within the same muscle as well between the muscles. It indicates that individual FFA are either selectively transported from the plasma to the muscles or selectively used within the myocytes or both.

Interleukin-1beta induced changes in the protein expression of rat islets: a computerized database

Insulin-dependent diabetes mellitus is caused by an autoimmune destruction of the beta-cells in the islets of Langerhans. The cytokine interleukin 1 inhibits insulin release and is selectively cytotoxic to beta-cells in isolated pancreatic rat islets. The antigen(s) triggering the immune response as well as the intracellular mechanisms of action of interleukin 1-mediated beta-cell cytotoxicity are unknown. However, previous studies have found an association of beta-cell destruction with alterations in protein synthesis. Thus, two-dimensional (2-D) gel electrophoresis of pancreatic islet proteins may be an important tool facilitating studies of the molecular pathogenesis of insulin-dependent diabetes mellitus. 2-D gel electrophoresis of islet proteins may lead to (i) the determination of qualitative and quantitative changes in specific islet proteins induced by cytokines, (ii) the determination of the effects of agents modulating cytokine action, and (iii) the identification of primary islet protein antigen(s) initiating the immune destruction of the beta-cells. Therefore, the aim of this study was to create databases (DB) of all reproducibly detectable protein spots on 10% and 15% acrylamide 2-D gels of neonatal rat islets (10% and 15% DB), labeled under standardized culture conditions. 1235 and 557 spots were present in 5 of 5 gels in the 15% isoelectric focusing (IEF) and nonequilibrium pH gradient electrophoresis (NEPHGE) DB, respectively, whereas 995 and 378 spots were present in 5 of 5 gels in the 10% IEF and NEPHGE DB, respectively, yielding a reproducibility of spot detection between 75.2% and 91.7%. In both DBs, the average coefficient of variation of the percentage of integrated optical density (CV% of %IOD) for spots present in all gels was between 42.4% and 45.7%. When the same sample was analyzed in consecutive sets of gels on different days (interassay analysis), the average CV% of %IOD was 35.5%-36.1%. When the same sample was analyzed repeatedly in one set of gels (intra-assay analysis), the average CV% of %IOD was 30.2% in the IEF gels, while the average CV% of %IOD was 45.7% in the NEPHGE gels. Addition of interleukin-1beta (IL-1beta) to the cultures resulted in statistically significant modulation or de novo synthesis of 105 proteins in the 10% gels. In conclusion, we present the first 10% and 15% acrylamide 2-D gel protein databases of neonatal rat islets of Langerhans and demonstrate its usage to identify proteins altered in expression by IL-1beta.

Proteome analysis of Saccharomyces cerevisiae: a methodological outline

Proteome analysis offers a unique means of identifying important proteins, characterizing their modifications and beginning to describe their function. This is achieved through the combination of two technologies: protein separation and selection by two-dimensional gel electrophoresis, and protein identification and characterization by mass spectrometry. This methodological outline sketches the strengths and weaknesses of the two central technologies used, and provides both practical tips and the theoretical background for their utilization. One application of these technologies is illustrated by the characterization of genes, revealed by sequencing, but which have no--or only weak homology--to any other known genes. Other applications, for example the identification of protein markers for particular human diseases, are only referred to. The aim of the article is thus to provide the basis for a sound understanding of the full potential and limitations of proteome analysis.

Effect of increased uptake of plasma fatty acids by the liver on lipid metabolism in the hepatocellular nuclei

The nucleus contains different lipids. The aim of the present study was to examine whether increased uptake of free fatty acids by the liver affects lipid metabolism in the hepatocellular nuclei. The experiments were carried out on three groups of Wistar rats: I - male, control; II - male, heparin-treated, and III - female. [14C]-palmitic acid suspended in rat donor serum was administered intravenously 5 and 30 min before tissue samples were taken. Lipids were extracted from isolated liver nuclei and separated into different fractions (phospholipids - PH, monoacylglycerols - MG, diacylglycerols - DG, cholesterol - CH, free fatty acids - FFA, triacylglycerols - TG and cholesterol esters - CHE). It was found that 5 min after administration of the label all isolated nuclear lipid fractions were radioactive. Most of the radioactivity was located in the fraction of PH, TG and FFA. Elevation in the plasma FFA concentration (heparin-treated group) resulted in increased incorporation of [14C]-palmitic acid into the nuclear lipids and changes in its distribution. In the female rats the radioactivity of nuclear lipids was higher than in the male-controls. There were also differences in the percentage distribution of the radioactivity in different lipid fractions between the two groups. The concentration of PH and TG in the nuclei increased only in the heparin-treated but not in the female rats. However, specific activity of the nuclear PH and TG increased in with both groups compared to the male-control group. It is concluded that (a) the blood-borne FFA rapidly enter the nuclear lipid pool and (b) increased uptake of the plasma-borne FFA by the liver affects the nuclear lipid metabolism.

The sequence of a 27 kb segment on the right arm of chromosome VII from Saccharomyces cerevisiae reveals MOL1, NAT2, RPL30B, RSR1, CYS4, PEM1/CHO2, NSR1 genes and ten new open reading frames

The DNA sequence of a 26,677 bp fragment from the right arm of chromosome VII from Saccharomyces cerevisiae reveals 18 open reading frames (ORFs) longer than 300 bp. Eight ORFs correspond to previously characterized genes. G6620 is the 3' end of the MOL1 gene coding for a polypeptide similar to stress-inducible proteins from Fusarium; G6630 is the NAT2 gene which encodes a methionine N-acetyltransferase; G6635 is the RPL30B gene coding for the ribosomal protein L30; G6658 is RSR1 encoding a ras-related protein; G6667 is CYS4, the gene for cystathionine beta-synthase; G6670 is identical to ORF2 located close to CYS4; G6673 is PEM1/CHO2 encoding a phosphatidylethanolamine methyltransferase; G7001 is the NSR1 gene coding for a nuclear signal recognition protein. G6664 shares significant homology with the ORF YKR076w from chromosome XI. The other nine ORFs show no significant homology to any protein sequence presently available in the public data bases.

Safe and effective isokinetic knee extension training in rheumatoid arthritis

OBJECTIVE

To evaluate the safety of isokinetic knee extensor strength training, and its effectiveness with regard to knee extension, in patients with rheumatoid arthritis (RA).

METHODS

Nine women with RA, all in functional stage II or III, underwent a low-intensity strengthening protocol with 48 repetitions at 50% of maximal voluntary contraction, 3 times per week for 3 weeks, using an isokinetic dynamometer.

RESULTS

Five patients had knee synovitis at entry; but neither synovitis nor joint pain increased. The mean gain in strength was 21%.

CONCLUSION

This training method was effective and safe in patients with RA.