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Moderate hypothermia induces marked increase in levels and nuclear accumulation of SUMO2/3-conjugated proteins in neurons.

ABSTRACT: Deep hypothermia protects the brain from ischemic damage and is therefore used during major cardiovascular surgeries requiring cardiopulmonary bypass and a period of circulatory arrest. Here, we demonstrated that small ubiquitin-like modifier (SUMO1-3) conjugation is markedly activated in the brain during deep to moderate hypothermia. Animals were subjected to normothermic (37°C) or deep to moderate (18°C, 24°C, 30°C) hypothermic cardiopulmonary bypass, and the effects of hypothermia on SUMO conjugation were evaluated by Western blot and immunohistochemistry. Exposure to moderate 30°C hypothermia was sufficient to markedly increase levels and nuclear accumulation of SUMO2/3-conjugated proteins in these cells. Deep hypothermia induced nuclear translocation of the SUMO-conjugating enzyme Ubc9, suggesting that the increase in nuclear levels of SUMO2/3-conjugated proteins observed in brains of hypothermic animals is an active process. Exposure of primary neuronal cultures to deep hypothermia induced only a moderate rise in levels of SUMO2/3-conjugated proteins. This suggests that neurons in vivo have a higher capacity than neurons in vitro to activate this endogenous potentially neuroprotective pathway upon exposure to hypothermia. Identifying proteins that are SUMO2/3 conjugated during hypothermia could help to design new strategies for preventive and therapeutic interventions to make neurons more resistant to a transient interruption of blood supply.

SUBMITTER: Wang L

PROVIDER: S-EPMC3466336 | biostudies-literature | 2012 Nov

REPOSITORIES: biostudies-literature

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Moderate hypothermia induces marked increase in levels and nuclear accumulation of SUMO2/3-conjugated proteins in neurons.

Wang Liangli L Ma Qing Q Yang Wei W Mackensen G Burkhard GB Paschen Wulf W

Journal of neurochemistry 20120912 3

Deep hypothermia protects the brain from ischemic damage and is therefore used during major cardiovascular surgeries requiring cardiopulmonary bypass and a period of circulatory arrest. Here, we demonstrated that small ubiquitin-like modifier (SUMO1-3) conjugation is markedly activated in the brain during deep to moderate hypothermia. Animals were subjected to normothermic (37°C) or deep to moderate (18°C, 24°C, 30°C) hypothermic cardiopulmonary bypass, and the effects of hypothermia on SUMO con ...[more]

PMID: 22891650

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Project description:Background: Moderate hypothermia (32oC for 12 – 72 hours) has therapeutic applications, but the mechanisms by which it affects cellular function are unclear. We tested the hypothesis that moderate hypothermia produces broad changes in gene expression by human cells at the level of mRNA. Methods: Acute monocytic leukemia THP-1 cells were incubated under control conditions (37oC) or moderate hypothermia (32oC) for 24 hours. Cellular mRNA was extracted and a cold stress response was confirmed by examining the expression of the cold-inducible gene CIRBP by reverse transcription PCR (RT-PCR). Gene expression analysis was performed on seven sets of samples with Affymetrix U133A chips, using established statistical methods. Sequences were considered to be affected by cold if they showed statistically significant changes in expression and also met published post-hoc filter criteria (changes in geometric mean expression of 2-fold or greater and detection calls of “present” or “marginal” in at least half of the experiments). The changes in expression of a select number of these sequences were further confirmed by PCR. Results: 167 sequences met our prospectively defined criteria for a change in expression; 67 showed increases in expression and 100 showed decreases in expression. Consistent with prior literature, the cold-inducible genes CIRBP and RBM3 showed increases in expression. Functional categories affected by cold stress included genes involved in immune responses, cell growth, proliferation, and differentiation, and metabolism and biosynthesis. Several heat shock proteins (HSPs) showed decreases in expression. Conclusions: Moderate hypothermia produces substantial changes in cellular gene expression, in categories potentially of importance to systemic function. Interestingly, cold exposure without re-warming decreased the expression of several HSPs. Our in vitro findings suggest that moderate hypothermia in vivo might produce physiologically important changes in gene expression by circulating leukocytes. Keywords: Stress response / hypothermia

Project description:BackgroundWe previously determined that polyplexes formed by linear H2K peptides were more effective in transfecting tumors in vivo than polyplexes formed by branched H2K4b-20 peptides. Based on trypsin digest and salt displacement studies, the linear H2K polyplexes were less stable than the branched H2K4b-20 polyplexes. Because binding and release of the polymer and DNA from the H2K4b-20 polyplex may account for the ineffectiveness, we investigated whether four-branched histidine-lysine (HK) peptides with varying numbers of amino acids in their branches would be more effective in their ability to increase gene expression in tumors in vivo.MethodsLinear and branched peptides with multiple -KHHK- motifs were synthesized by solid-phase synthesis. The branched H2K4b-20, -18, -14 and 12 peptides had 20, 18, 14 and 12 amino acids in their branches, respectively. These peptides were examined for their ability to carry luciferase-expressing plasmids to human breast cancer xenografts in a mouse model. With gel retardation and in vivo transfection, the incorporation of a targeting ligand and an endosomal lysis peptide into these polyplexes was also examined. A blocking antibody was pre-injected prior to the polyplexes to determine the role of neuropilin 1 in the uptake of these polyplexes by the tumor. The size of the polyplexes was measured by dynamic light scattering.ResultsOf the four negative surface-charge polyplexes formed by the branched carriers, the H2K4b-14 polyplex was determined to be the most effective plasmid delivery platform to tumors. The incorporation of a targeting ligand and an endosomal lysis peptide into H2K4b-14 polyplexes further enhanced their ability to transfect tumors in vivo. Furthermore, after pre-injecting tumor-bearing mice with a blocking antibody to the neuropilin-1 receptor (NRP-1), there was a marked reduction of tumor gene expression with the modified H2K4b-14 polyplexes, suggesting that NRP-1 mediated their transport into the tumor.ConclusionsThe present study established that branched peptides intermediate in length were very efficient in delivering plasmids to tumors in vivo.

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Moderate hypothermia induces marked increase in levels and nuclear accumulation of SUMO2/3-conjugated proteins in neurons.

Publications

Moderate hypothermia induces marked increase in levels and nuclear accumulation of SUMO2/3-conjugated proteins in neurons.

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