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Gene expression profiling reveals potential prognostic biomarkers associated with the progression of heart failure
Get PDFAbstract
BACKGROUND:
Heart failure (HF) is the most common cause of morbidity and mortality in developed countries. Here, we identify biologically relevant transcripts that are significantly altered in the early phase of myocardial infarction and are associated with the development of post-myocardial infarction HF.
METHODS:
We collected peripheral blood samples from patients with ST-segment elevation myocardial infarction (STEMI): n = 111 and n = 41 patients from the study and validation groups, respectively. Control groups comprised patients with a stable coronary artery disease and without a history of myocardial infarction. Based on plasma NT-proBNP level and left ventricular ejection fraction parameters the STEMI patients were divided into HF and non-HF groups. Microarrays were used to analyze mRNA levels in peripheral blood mononuclear cells (PBMCs) isolated from the study group at four time points and control group. Microarray results were validated by RT-qPCR using whole blood RNA from the validation group.
RESULTS:
Samples from the first three time points (admission, discharge, and 1 month after AMI) were compared with the samples from the same patients collected 6 months after AMI (stable phase) and with the control group. The greatest differences in transcriptional profiles were observed on admission and they gradually stabilized during the follow-up. We have also identified a set of genes the expression of which on the first day of STEMI differed significantly between patients who developed HF after 6 months of observation and those who did not. RNASE1, FMN1, and JDP2 were selected for further analysis and their early up-regulation was confirmed in HF patients from both the study and validation groups. Significant correlations were found between expression levels of these biomarkers and clinical parameters. The receiver operating characteristic (ROC) curves indicated a good prognostic value of the genes chosen.
CONCLUSIONS:
This study demonstrates an altered gene expression profile in PBMCs during acute myocardial infarction and through the follow-up. The identified gene expression changes at the early phase of STEMI that differentiated the patients who developed HF from those who did not could serve as a convenient tool contributing to the prognosis of heart failure
Double Bond Stereochemistry Influences the Susceptibility of Short‑Chain Isoprenoids and Polyprenols to Decomposition by Thermo‑Oxidation
Get PDFAlcohols are common constituents of
living cells. They are usually assigned a role in the adaptation
of the cell to environmental stimuli, and this process
might give rise to their oxidation by reactive oxygen
species. Moreover, cellular isoprenoids may also undergo
various chemical modifications resulting from the physicochemical
treatment of the tissues, e.g., heating during food
processing. Susceptibility of isoprenoid alcohols to heat
treatment has not been studied in detail so far. In this study,
isoprenoid alcohols differing in the number of isoprene units
and geometry of the double bonds, β-citronellol, geraniol,
nerol, farnesol, solanesol and Pren-9, were subjected to
thermo-oxidation at 80 °C. Thermo-oxidation resulted in the
decomposition of the tested short-chain isoprenoids as well
as medium-chain polyprenols with simultaneous formation
of oxidized derivatives, such as hydroperoxides, monoepoxides,diepoxides and aldehydes, and possible formation of oligomeric derivatives. Oxidation products were monitored by GC-FID, GC-MS, ESI-MS and spectrophotometric methods. Interestingly, nerol, a short-chain isoprenoid with a double bond in the cis (Z) configuration, was more oxidatively stable than its trans (E) isomer, geraniol. However, the opposite effect was observed for medium-chain polyprenols, since Pren-9 (di-trans-poly-cis-prenol) was more susceptible to thermo-oxidation than its all-trans isomer, solanesol. Taken together, these results experimentally confirm that both short- and long-chain polyisoprenoid alcohols are prone to thermo-oxidation
Role of Rsp5 ubiquitin ligase in biogenesis of rRNA, mRNA and tRNA in yeast
Get PDFRsp5 ubiquitin ligase is required for ubiquitination of a wide variety of proteins involved in essential processes. Rsp5 was shown to be involved in regulation of lipid biosynthesis, intracellular trafficking of proteins, response to various stresses, and many other processes. In this article, we provide a comprehensive review of the nuclear and cytoplasmic functions of Rsp5 with a focus on biogenesis of different RNAs. We also briefly describe the participation of Rsp5 in the regulation of the RNA polymerase II complex, and its potential role in the regulation of other RNA polymerases. Moreover, we emphasize the function of Rsp5 in the coordination of the different steps of rRNA, mRNA and tRNA metabolism in the context of protein biosynthesis. Finally, we highlight the involvement of Rsp5 in controlling diverse cellular mechanisms at multiple levels and in adaptation of the cell to changing growth conditions
Microbial community changes along the Ecology Glacier ablation zone (King George Island, Antarctica)
Get PDFIn recent years glacial surfaces have received much attention as microbial habitats of diverse
photoautotrophic and heterotrophic cells. Supraglacial ecosystems are annually covered and
uncovered by snow. The aim of this study was to investigate the microbial community
response to changing environmental conditions in a transect following the receding snow line
on the surface of Ecology Glacier (King George Island, Antarctica). Parameters of surface ice
and cryoconite holes included chemical composition of ice and sediment, Bacteria diversity
by denaturating gradient gel electrophoresis (DGGE), microbial functional diversity (Biolog
Ecoplates), and microbial counts (epifluorescence microscopy, colony forming units - CFU).
Data demonstrated profound differences between surface ice and cryoconite holes. Changing
environmental factors along the transect influenced composition and abundance of the
microbiocenosis in both habitat types. Several parameters correlated positively with distance
from the glacier edge, including the cell morphotype Shannon Index, chlorophyll a, nitrogen
and seston concentrations. Suspended solids content positively correlated with microbial
2
abundance and diversity. Nitrogen and phosphorus were limiting factors of microbial growth
as amounts of organic nitrogen and phosphorus positively correlated with the cell numbers,
fission rates and photoautotroph contribution. Our findings indicate that microbial community
shows a response in terms of abundance and diversity to exposure of the glacial surface as
snow-cover melts. To our knowledge this is the first study to recognize a microbial
development pattern on a glacier surface in connection with the receding snow line. This may
help better understand variability within supraglacial habitats, correct sampling procedures
and inform biocenotic development models
Modelling of Thyroid Peroxidase Reveals Insights into Its Enzyme Function and Autoantigenicity
Get PDFThyroid peroxidase (TPO) catalyses the biosynthesis of thyroid hormones and is a major autoantigen in Hashimoto’s disease—the most common organ-specific autoimmune disease. Epitope mapping studies have shown that the autoimmune response to TPO is directed mainly at two surface regions on the molecule: immunodominant regions A and B (IDR-A, and IDR-B). TPO has been a major target for structural studies for over 20 years; however, to date, the structure of TPO remains to be determined. We have used a molecular modelling approach to investigate plausible modes of TPO structure and dimer organisation. Sequence features of the C-terminus are consistent with a coiled-coil dimerization motif that most likely anchors the TPO dimer in the apical membrane of thyroid follicular cells. Two contrasting models of TPO were produced, differing in the orientation and exposure of their active sites relative to the membrane. Both models are equally plausible based upon the known enzymatic function of TPO. The “trans” model places IDR-B on the membrane-facing side of the myeloperoxidase (MPO)-like domain, potentially hindering access of autoantibodies, necessitating considerable conformational change, and perhaps even dissociation of the dimer into monomers. IDR-A spans MPO- and CCP-like domains and is relatively fragmented compared to IDR-B, therefore most likely requiring domain rearrangements in order to coalesce into one compact epitope. Less epitope fragmentation and higher solvent accessibility of the “cis” model favours it slightly over the “trans” model. Here, IDR-B clusters towards the surface of the MPO-like domain facing the thyroid follicular lumen preventing steric hindrance of autoantibodies. However, conformational rearrangements may still be necessary to allow full engagement with autoantibodies, with IDR-B on both models being close to the dimer interface. Taken together, the modelling highlights the need to consider the oligomeric state of TPO, its conformational properties, and its proximity to the membrane, when interpreting epitope-mapping data
Mistargeted mitochondrial proteins activate a proteostatic response in the cytosol.
Get PDFMost of the mitochondrial proteome originates from nuclear genes and is transported into the mitochondria after synthesis in the cytosol. Complex machineries which maintain the specificity of protein import and sorting include the TIM23 translocase responsible for the transfer of precursor proteins into the matrix, and the mitochondrial intermembrane space import and assembly (MIA) machinery required for the biogenesis of intermembrane space proteins. Dysfunction of mitochondrial protein sorting pathways results in diminishing specific substrate proteins, followed by systemic pathology of the organelle and organismal death. The cellular responses caused by accumulation of mitochondrial precursor proteins in the cytosol are mainly unknown. Here we present a comprehensive picture of the changes in the cellular transcriptome and proteome in response to a mitochondrial import defect and precursor over-accumulation stress. Pathways were identified that protect the cell against mitochondrial biogenesis defects by inhibiting protein synthesis and by activation of the proteasome, a major machine for cellular protein clearance. Proteasomal activity is modulated in proportion to the quantity of mislocalized mitochondrial precursor proteins in the cytosol. We propose that this type of unfolded protein response activated by mistargeting of proteins (UPRam) is beneficial for the cells. UPRam provides a means for buffering the consequences of physiological slowdown in mitochondrial protein import and for counteracting pathologies that are caused or contributed by mitochondrial dysfunction
Arabidopsis ABA-activated kinase MAPKKK18 is regulated by protein phosphatase 2C ABI1 and the ubiquitin proteasome pathway
Get PDFPhosphorylation and dephosphorylation events play an important role in the transmission of the abscisic acid signal. Although SnRK2 protein kinases and group A PP2C-type phosphatases constitute a core ABA pathway, little is known about the interplay between MAP kinases and protein phosphatases 2C in the regulation of ABA pathways. In this study, an effort was made to elucidate the role of MKKK18 in relation to ABA signaling and response. The MKKK18 knockout lines showed more vigorous root growth, decreased abaxial stomatal index, and increased stomatal aperture under normal growth conditions, compared to the control WT Col-0 line. In addition to transcriptional regulation of the MKKK18 promoter by ABA, we demonstrated by using in vitro and in vivo kinase assays that the kinase activity of MKKK18 was regulated by ABA and in response to H2O2 treatment. Analysis of the cellular localization of MKKK18 showed that the active kinase was targeted specifically to the nucleus. Notably, we identified ABI1 PP2C as a MKKK18-interacting protein, and demonstrated that ABI1 inhibited its activity. Using a cell-free degradation assay, we also established that MKKK18 was unstable and was degraded by the proteasome pathway. The rate of MKKK18 degradation was delayed in the ABI1 knockout line. Overall, we provide evidence that ABI1 regulates activity and promotes proteasomal degradation of MKKK18
Genistein inhibits activities of methylenetetrahydrofolate reductase and lactate dehydrogenase, enzymes which use NADH as a substrate
Get PDFGenistein (5, 7-dihydroxy-3- (4-hydroxyphenyl)-4H-1 benzopyran-4-one) is a natural isoflavone revealing many biological activities. Thus, it is considered as a therapeutic compound in as various disorders as cancer, infections and genetic diseases. Here, we demonstrate for the first time that genistein inhibits activities of bacterial methylenetetrahydrofolate reductase (MetF) and lactate dehydrogenase(LDH). Both enzymes use NADH as a substrate, and results of biochemical as well as molecular modeling studies with MetF suggest that genistein may interfere with binding of this dinucleotide to the enzyme.
These results have implications for our understanding of biological functions of genistein and its effects on cellular metabolism
Modulation of expression of genes involved in glycosaminoglycan metabolism and lysosome biogenesis by flavonoids
Get PDFFlavonoids were found previously to modulate efficiency of synthesis of glycosaminoglycans (GAGs),
compounds which are accumulated in cells of patients suffering from mucopolysaccharidoses (MPSs). The
aim of this work was to determine effects of different flavonoids (genistein, kaempferol, daidzein) used alone
or in combinations, on expression of genes coding for proteins involved in GAG metabolism. Analyses with
DNA microarray, followed by real-time qRT-PCR revealed that genistein, kaempferol and combination of
these two compounds induced dose- and time-dependent remarkable alterations in transcript profiles of
GAG metabolism genes in cultures of wild-type human dermal fibroblasts (HDFa). Interestingly, effects of
the mixture of genistein and kaempferol were stronger than those revealed by any of these compounds used
alone. Similarly, the most effective reduction in levels of GAG production, in both HDFa and MPS II cells, was observed in the presence of genistein, keampferol and combination of these compounds. Forty five genes were chosen for further verification not only in HDFa, but also inMPS II fibroblasts by using real-time qRT-PCR. Despite effects on GAG metabolism-related genes, we found that genistein, kaempferol and mixture of these compounds significantly stimulated expression of TFEB. Additionally, a decrease inMTOR transcript level was observed at these conditions
Oral administration of Lactococcus lactis expressing synthetic genes of myelin antigens in decreasing experimental autoimmune encephalomyelitis in rats
Get PDFABSTRACT
Background: Multiple sclerosis is a human autoimmunological disease that causes neurodegeneration. One of the potential ways to stop its development is induction of oral tolerance, whose effect lies in decreasing immune response to the fed antigen. It was shown on animal models that administration of specific epitopes of the three main myelin proteins, myelin oligodendrocyte glycoprotein (MOG), myelin basic protein (MBP) and proteolipid protein (PLP) results in induction of oral tolerance and suppression of disease symptoms. Application of bacterial cells to produce and deliver antigens to gut mucosa seems to be an attractive method for oral tolerance induction in treatment of diseases with autoimmune background.
Material/Methods: Synthetic genes of MOG35-55, MBP85-97 and PLP139-151 myelin epitopes were generated and cloned in Lactococcus lactis under a CcpA-regulated promoter. The tolerogenic effect of bacterial preparations was tested on experimental autoimmune encephalomyelitis, the animal model of MS. EAE was induced in rats by intradermal injection of guinea pig homogenate into hind paws.
Results: Rats were administered preparations containing whole-cell lysates of L. lactis producing myelin antigens using different feeding schemes. Our study demonstrates that 20-fold, but not 4-fold, intragastric administration of autoantigen-expressing L. lactis cells under specific conditions reduces the clinical symptoms of EAE in rats.
Conclusions: The present study evaluates the use of myelin antigens produced in L. lactis in inhibiting the on-set of experimental autoimmune encephalomyelitis in rats. Obtained results indicate that application of such recombinant cells can be an attractive method of oral tolerance induction