ABSTRACT
Rat aortic smooth muscle cells (RASM) express the src suppressed C-kinase substrate (SSeCKS), which is thought to be an integral regulatory component of cytoskeletal dynamics and G-protein coupled-receptor signaling modules. The specific sub-classes of growth factor receptors that regulate the genomic changes in SSeCKS expression in smooth muscle cells have not been characterized. In this study we identify SSeCKS as an angiotensin type 1 (AT(1)) receptor-dependent target gene in RASM cells treated with angiotensin II (Ang II). SSeCKS mRNA levels increase up to three-fold relative to the control within 3.5 h of Ang II treatment and are followed by a slight decrease of mRNA relative to the control levels after 24 h of stimulation. SSeCKS gene expression and plasminogen activator inhibitor-1 (PAI-1) gene expression correlate in RASM cells treated with Ang II. By co-transfecting plasmids bearing recombinant-SSeCKS and a PAI-1-promoter/luciferase reporter into Cos-1 cells, we show that alternative forms of recombinant-SSeCKS protein differentially influence PAI-1 promoter activity. These data indicate a biochemical linkage between SSeCKS activity and one or more of the cytoplasmic signaling pathways that are involved in the control of PAI-1 promoter activity. Finally, we show that the alternative forms of recombinant-SSeCKS protein differentially influence cell-spreading when ectopically expressed in ras -transformed rat kidney (KNRK) fibroblasts. Taken together, our data suggest that SSeCKS interacts with intracellular signaling pathways that control cytoskeletal remodeling and extracellular matrix remodeling following Ang II stimulation of the RASM cell.
Subject(s)
Angiotensin II/metabolism , Cell Cycle Proteins , Gene Expression Regulation , Mitogens/biosynthesis , Mitogens/physiology , Muscle, Smooth, Vascular/cytology , Plasminogen Activator Inhibitor 1/biosynthesis , A Kinase Anchor Proteins , Angiotensin I/metabolism , Angiotensin II/pharmacology , Animals , Blotting, Northern , Blotting, Western , COS Cells , Cells, Cultured , Cytoplasm/metabolism , Cytoskeleton/metabolism , Dose-Response Relationship, Drug , Fibroblasts/metabolism , Fluorescent Antibody Technique , Gene Expression Profiling , Genes, Reporter , Luciferases/metabolism , Mitogens/genetics , Plasmids/metabolism , Promoter Regions, Genetic , RNA, Messenger/metabolism , RNA, Ribosomal, 18S/metabolism , RNA, Ribosomal, 28S/metabolism , Rats , Recombinant Proteins/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Serine Proteinase Inhibitors/biosynthesis , Signal Transduction , Time Factors , TransfectionABSTRACT
Unlike the clinical usages of evoked potentials (e.g. brain stem auditory evoked potentials for the assessment of auditory function), normative data for the olfactory event-related potential (OERP) have been unavailable. The principal objective was to establish normative data across the human life span for OERPs with a given set of parameters. Participants were 140 persons from seven age groups (16-19, 20-29, 30-39, 40-49, 50-59, 60-69 and 70-79 years of age), with equal numbers of males and females, screened for nasal health and dementia. The odor stimulus was amyl acetate, presented at nasal temperature in a humidified airstream delivered by an air-dilution olfactometer at a constant flow rate, using a 60-s inter-stimulus interval. OERPs were recorded at Fz, Cz, and Pz electrode sites, amplified and averaged over trials. Amplitudes of the N1/P2 and P3 and latencies of the P2 and P3 were analyzed. Processing speed decreased at a constant rate over decades for the sensory (P2 latency) as well as cognitive (P3 latency) components. Decline in amplitude over decades was also apparent. Normative data will be useful in research on olfactory function and in clinical assessment of olfactory functional status.
Subject(s)
Aging/physiology , Electroencephalography/standards , Evoked Potentials/physiology , Smell/physiology , Adolescent , Adult , Aged , Aged, 80 and over , Cognition/physiology , Female , Humans , Male , Middle Aged , Odorants , Reference Values , Regression Analysis , Sensory Thresholds/physiology , Sex CharacteristicsABSTRACT
Olfactory event-related potentials (OERPs) were recorded in 14 young and 14 older adults, with odor strength of isoamyl acetate manipulated to assess olfactory stimulus intensity. Young participants produced significantly larger N1/P2, N2/P3 amplitudes and shorter N1, P2 and N2 latencies than older participants. Medium- and high-odor concentrations elicited significantly shorter P2 and N2 latencies than the lowest concentration for both age groups. Odor concentration appears to affect the speed of olfactory stimulus information processing regardless of age.
Subject(s)
Aging/physiology , Cerebral Cortex/physiology , Evoked Potentials/physiology , Reaction Time/physiology , Smell/physiology , Adult , Aged , Analysis of Variance , Cross-Sectional Studies , Discrimination, Psychological/physiology , Female , Humans , Male , Psychophysics , Sensory Thresholds/physiologyABSTRACT
The P3 event-related brain potential (ERP) reflects neuroelectric activity related to the speed of cognitive processing and allocation of attentional resources. The objective of the present study was to assess the relationship between the P3 and Slow Wave components of the olfactory event-related potential (OERP) with neuropsychological performance in young (n = 16) and elderly (n = 16) adults. OERPs were recorded monopolarly from midline electrode sites while subjects estimated the odor magnitude of each stimulus, eliciting highly reproducible P3s. Results showed that the late cognitive components (P3 amplitude, P3 latency and Slow Wave area) decline with age and that this decreased neuronal efficiency is associated with reductions in the neuropsychological performance indexed by the Trail Making Test and the California Verbal Learning Test.
Subject(s)
Aging/physiology , Event-Related Potentials, P300/physiology , Mental Processes/physiology , Smell/physiology , Adult , Aged , Female , Humans , Male , Memory , Neuropsychological TestsABSTRACT
Olfactory event-related potentials (OERPs) were recorded monopolarly at the Fz, Cz, and Pz electrode sites in 16 young adults and 16 older adults to assess aging effects on the olfactory P3. Amyl acetate was used to elicit the OERPs, with an intertrial interval of 45 s. Young adults produced significantly larger P3 amplitudes and shorter P3 peak latencies than older adults. The olfactory P3 response appears to be sensitive to age-related changes in the olfactory system and may reflect cognitive slowing in the central nervous system.
Subject(s)
Aging/physiology , Cerebral Cortex/physiology , Evoked Potentials/physiology , Olfactory Pathways/physiology , Reaction Time/physiology , Smell/physiology , Adult , Aged , Analysis of Variance , Cross-Sectional Studies , Female , Humans , MaleABSTRACT
This study was designed to characterize the direct effects of hyperglycemia on plasminogen activator inhibitor-1 (PAI-1) expression in cultured vascular smooth muscle cells. Glucose induced dose- and time-dependent increases of PAI-1 mRNA expression in rat aortic smooth muscle (RASM) cells in vitro. Using a series of luciferase reporter gene constructs containing PAI-1 5'-flanking sequence (from -6.4 kilobase to -42 base pairs (bp)) transfected into RASM, we found that glucose (25 mM) consistently induced a 4-fold increase in luciferase activity, with the response localized to sequence between -85 and -42 bp. Mutagenesis of two putative Sp1-binding sites located in the region of interest essentially obliterated the glucose-response. Electrophoretic mobility shift assays with radiolabeled oligonucleotides containing the two putative Sp1-binding sites from PAI-1 promoter and nuclear extracts from RASM cells revealed that glucose treatment markedly changed the mobility pattern of the major protein-DNA complexes. Supershift assay showed that transcription factor Sp1 was present in the complexes under control and hyperglycemic conditions. These results suggest that glucose regulates PAI-1 gene expression in RASM cells through an effect on two adjacent Sp1 sites located between -85 and -42 bp of the PAI-1 5'-flanking region and that the release of a transcriptional repressor from the Sp1 complexes may explain the activation of the PAI-1 gene under high glucose conditions in RASM cells.
Subject(s)
Glucose/pharmacology , Muscle, Smooth, Vascular/metabolism , Plasminogen Activator Inhibitor 1/metabolism , Sp1 Transcription Factor/metabolism , Animals , Gene Expression Regulation/drug effects , Mutagenesis , Plasminogen Activator Inhibitor 1/genetics , Promoter Regions, Genetic/genetics , Rats , Sp1 Transcription Factor/geneticsABSTRACT
Olfactory event-related potentials (OERPs) were recorded monopolarly at the Fz, Cz, and Pz electrode sites in 16 young adults (8M/8F) and 16 older adults (8M/8F) with inter-stimulus intervals (ISI) of 45, 60 and 90 s using amyl acetate as the odorant stimulus. N1, P2, and N2 peak amplitudes and latencies were measured. Young participants demonstrated significantly shorter peak latencies than older participants. Older males demonstrated significantly smaller peak amplitudes than the other participant groups. Peak amplitudes also increased with longer ISIs for older males. The OERP is compared to traditional olfactory psychophysical testing.
Subject(s)
Aging/physiology , Evoked Potentials/physiology , Smell/physiology , Adult , Aged , Analysis of Variance , Female , Humans , Male , Middle Aged , Sex FactorsABSTRACT
Auditory and visual stimulus intensity levels were manipulated systematically in separate conditions to assess the influence of these variables on the P300 event-related brain potential (ERP). Increases in stimulus intensity produced increases in P300 amplitude and decreases in peak latency for both modalities, although the latency effects were stronger for visual stimulation. Similar, somewhat weaker stimulus intensity effects also were observed for the N100, P200, and N200 components. The findings suggest that stimulus intensity contributes to both P300 amplitude and latency measures in important ways and are discussed in relation to the use of ERPs in applied contexts.