Adipose differentiation-related protein (ADRP) is localized to lipid droplets in most mammalian cells. ADRP, proposed to regulate fatty acid mobilization and lipid droplet formation, is linked to lipid accumulation in foam cells of human atherosclerotic lesions. In this report, we show that ADRP protein accumulates in Chinese hamster ovary fibroblastic cells cultured in the presence of oleic acid but is destabilized when fatty acid sources are removed from culture serum. The latter effect was blocked by the proteasome inhibitor MG132, whereas inhibitors of other proteolytic processes were ineffective. Pulse-chase experiments confirmed that ADRP degradation is inhibited by MG132. Conditions that stimulate ADRP degradation also promoted the covalent modification of ADRP by ubiquitin, whereas the addition of oleic acid to culture media, which promotes triacylglycerol deposition, blunted the appearance of ubiquitinated-ADRP. Treatment with MG132 increased the levels of ADRP associated with lipid droplets, as well as throughout the cytosol. Finally, we demonstrate that the disappearance of ADRP protein after the onset of perilipin expression during adipocyte differentiation is due to degradation by proteasomes Thus, proteolytic degradation of ADRP mediated through the ubiquitin/proteasome pathway appears to be a major mode for the post-translational regulation of ADRP.

Penetrating brain injury (PBI) is a leading cause of mortality and morbidity in modern warfare and accounts for a significant number of traumatic brain injuries worldwide. Here we characterize the pathophysiology of a new rat model of PBI that simulates the large temporary cavity caused by energy dissipation from a penetrating bullet round. Male Sprague-Dawley rats (250-300 g) were subjected to a simulated ballistic wound to the right frontal hemisphere implemented by an inflatable penetrating probe. Three levels of injury severity were compared to control animals. Neurological and physiological outcome was assessed over a 3-day recovery period and brain tissue collected at 72 h for histopathological evaluation. Brain-injured regions included the ipsilateral frontal cortex and striatum with volumetric increases in intracranial hemorrhage (5-18 mm3) and lesion size (9-86 mm3) related to severity. Similarly, hemispheric swelling increased (3-14%) following PBI, associated with a significant rise in intracranial pressure. Astrogliosis was present in regions adjacent to the core-injury along with microglial and leukocyte infiltration. Injury remote to the lesion was observed in the cerebral peduncle that may have accounted, in part, for observed neurological deficits. Neurological and balance beam testing revealed sensorimotor deficits that persisted through 72 h. Severe electroencephalographic disturbances included the occurrence of cortical spreading depression, slow-waves, and brain seizure activity. In conclusion, this rat PBI model replicates diverse, salient features of clinical PBI pathology, generates reproducible and quantifiable measures of outcome, and is scalable by injury severity, rendering it an attractive vehicle for experimental brain trauma research.

The Perilipins are a family of intracellular neutral lipid droplet storage proteins that are responsive to acute protein kinase A-mediated, hormonal stimulation. Perilipin (Peri) expression appears to be limited to adipocytes and steroidogenic cells, in which intracellular neutral lipid hydrolysis is regulated by protein kinase A. We have isolated cDNA sets and overlapping genomic fragments of the murine Peri locus and mapped chromosomal location, transcription start sites, polyadenylylation sites, and intron/exon junctions. Data confirm that the Perilipins are encoded by a single-copy gene, with alternative and tissue-specific, mRNA splicing and polyadenylylation yielding four different protein species. The Perilipin proteins have identical approximately 22-kDa amino termini with distinct carboxyl terminal sequences of varying lengths. These genomic and transcriptional maps of murine Perilipin are also essential for evaluating presumptive endogenous and targeted mutations within the locus. The N-terminal identity region of the Perilipins defines a sequence motif, which we term PAT, that is shared with the ADRP and TIP47 proteins; additionally, the PAT domain may represent a novel, conserved pattern for lipid storage droplet (LSD) proteins of vertebrates and invertebrates alike. Comparative genomics suggest the presence of related LSD genes in species as diverse as Drosophila and Dictyostelium.

Ectopic accumulation of lipid droplets in non-adipose tissues correlates with the degree of insulin resistance in these tissues. Emerging evidence indicates that lipid droplets are specialized organelles that participate in lipid metabolism and intracellular trafficking. These properties are thought to derive from the lipid droplet-associated PAT protein family (perilipin, ADFP, and Tip47). The functions of the ubiquitously distributed adipose differentiation-related protein (ADFP) and Tip47 remain unknown. To evaluate the roles of ADFP and Tip47 in lipid biogenesis and metabolism, ADFP null and wild type (wt) clonal cell lines were established from ADFP null and wt mice, respectively. In ADFP null cells, Tip47 was identified as the sole lipid droplet-associated protein from the PAT family by mass spectroscopy, which was further confirmed by immunoblotting and immunocytochemistry. Following incubation with oleic acid, ADFP null cells were able to form lipid droplets to the same extent as wt cells. No statistical differences between the two cell types were observed in NEFA uptake or lipolysis. Small interference RNAs (siRNAs) against Tip47 were found to down-regulate protein levels for Tip47 by 85%. ADFP null cells treated with Tip47 siRNA retained the ability to form lipid droplets but to a lesser extent and shunted the utilization of exogenously added NEFA from triglycerides to phospholipids. These data support the hypothesis that Tip47 plays an important role in lipid metabolism. Tip47 and ADFP in peripheral tissues may play a critical role in regulating the formation and turnover, and hence metabolic consequences, of ectopic fat.Ectopic fat deposition, the accumulation of lipids in lipid droplets in tissues other than adipose, develops in obese patients and is now recognized as a strong prognostic factor for the development of metabolic syndrome (1-3). The molecular mechanisms regulating the formation and metabolism of lipid droplets in non-adipose tissues and their dysfunction in pathophysiological states are not well understood. Recent proteomic studies indicate that lipid droplets are surrounded by a protein coat that provides an interface for lipid metabolic processes, including transport, lipogenesis, and lipolysis (4 -8). Even more importantly, these studies identify a proteome "signature" for lipid droplets that consistently includes at least one member of the PAT protein family (originally named for perilipin, ADFP and Tip47). A PAT protein is always present and generally represents the most abundant lipid droplet protein, suggesting at least an important structural role for this class of proteins in lipid droplet machinery.The mammalian PAT family includes five members: perilipin, ADFP, 3 tail interacting protein of 47 kDa (Tip47), S3-12, and PAT-1 (9). The PAT proteins are defined by primary sequence homology and are well conserved within the family and across species (10). Recent proteomic studies revealed heterogeneity and tissue-specific differences in droplet-associated proteins (4 -8). PAT prot...

Temporal changes in gene expression were measured using DNA microarrays after 30-min or 2-hr transient middle cerebral artery occlusion (MCAo) in rats. Total RNA was extracted from the injured hemisphere at 30 min, 4 hr, 8 hr, 24 hr, 3 days, and 7 days after MCAo for GeneChip analysis using Affymetrix U34 Rat Neurobiology arrays (1,322 functional genes). In total, 267 genes were expressed differentially: 166 genes were upregulated, 94 genes were downregulated, and 7 genes were biphasically up- and downregulated. Among all differentially expressed genes, 88 were newly identified as associated with ischemic brain injury. Most affected genes were distributed among 12 functional categories. Immediate early genes, transcription factors, and heat shock proteins were upregulated as early as 30 min after MCAo, followed by the upregulation of inflammation, apoptosis, cytoskeletal, and metabolism genes, which peaked within 4-24 hr of injury. Neurotrophic growth factors exhibited a sustained upregulation beginning 24 hr after MCAo and persisting through 7 days post-injury. Three classes of genes were downregulated with distinct temporal patterns: ion channel genes and neurotransmitter receptor genes were downregulated between 8-24 hr after injury, whereas synaptic proteins genes were downregulated between 3-7 days after MCAo. Downregulation of synaptic protein gene expression after ischemic injury is of particular interest because of its conspicuously delayed pattern as a functional group, which has not been reported previously and may play a role in post-injury recovery.

No abstract

Electroencephalography (EEG) has a long history in clinical evaluations of cerebrovascular disease. Distinct EEG abnormalities, such as increased slow delta activity, voltage depression and epileptiform discharge, have been identified in stroke patients. However, preclinical use of EEG analysis of cerebral ischaemia is less documented. We report a new rat model of EEG topographic mapping during permanent and transient middle cerebral artery occlusion. Ten EEG electrodes were implanted on the rat skull, symmetrically covering the cortical regions of two hemispheres. Monopolar EEG recordings were acquired from each animal at multiple time points during the initial 24 h, and again once daily for 7 days. Traditional EEG examinations, quantitative EEG (qEEG) spectral analysis and topographic EEG mapping were employed for comprehensive data analyses. Several distinct spatiotemporal EEG abnormalities were identified in the ischaemic rat brain. In the ipsilateral hemisphere, pronounced increase in delta activity was observed in each recorded area within 24 h of injury. While sharp waves and spike complexes dominated the parietal region, a nearly isoelectric EEG state was seen in the temporal region. After 48 h, spontaneous, albeit incomplete, recovery of EEG activities developed in all rats. Reperfusion appeared to promote delta and alpha recovery more efficiently. The contralateral EEG changes were also recorded in two phases: an acute moderate increase in delta activities with intermittent rhythmic activities, followed by a delayed and significant increase in beta activities across the hemisphere. The similarities of rat qEEG profiles identified in this study to that of stroke patients and the application of topographic mapping broaden our research technology for preclinical experimental studies of brain injury.

Background: Aging has often been linked to age-related vascular disorders. The elucidation of the putative genes and pathways underlying vascular aging likely provides useful insights into vascular diseases at advanced ages. Transcriptional regulatory network analysis is the key to describing genetic interactions between molecular regulators and their target gene transcriptionally changed during vascular aging.Results: A total of 469 differentially expressed genes were parsed into 6 modules. Among the incorporated sample traits, the most significant module related to vascular aging was associated with triglyceride and enriched with biological terms like proteolysis, blood circulation, and circulatory system process. The module associated with triglyceride was preserved in an independent microarray dataset, indicating the robustness of the identified vascular aging-related subnetwork. Additionally, Enpp5, Fez1, Kif1a, F3, H2-Q7, and their interacting miRNAs mmu-miR-449a, mmu-miR-449c, mmu-miR-34c, mmu-miR-34b-5p, mmu-miR-15a, and mmu-let-7, exhibited the most connectivity with external lipid-related traits. Transcriptional alterations of the hub genes Enpp5, Fez1, Kif1a, and F3, and the interacting microRNAs mmu-miR-34c, mmu-miR-34b-5p, mmu-let-7, mmu-miR-449a, and mmu-miR-449c were confirmed.Conclusion: Our findings demonstrate that triglyceride and free fatty acid-related genes are key regulators of age-related vascular dysfunction in mice and show that the hub genes for Enpp5, Fez1, Kif1a, and F3 as well as their interacting miRNAs mmu-miR-34c, mmu-miR-34b-5p, mmu-let-7, mmu-miR-449a, and mmu-miR-449c, could serve as potential biomarkers in vascular aging.Methods: The microarray gene expression profiles of aorta samples from 6-month old mice (n=6) and 20-month old mice (n=6) were processed to identify nominal differentially expressed genes. These nominal differentially expressed genes were subjected to a weighted gene co-expression network analysis. A network-driven integrative analysis with microRNAs and transcription factors was performed to define significant modules and underlying regulatory pathways associated with vascular aging, and module preservation test was conducted to validate the age-related modules based on an independent microarray gene expression dataset in mice aorta samples including three 32-week old wild-type mice (around 6-month old) and three 78-week old wild-type mice (around 20-month old). Gene ontology and protein-protein interaction analyses were conducted to determine the hub genes as potential biomarkers in the progress of vascular aging. The hub genes were further validated with quantitative real-time polymerase chain reaction in aorta samples from 20 young (6-month old) mice and 20 old (20-month old) mice.