Limits...
Global protein conjugation by ubiquitin-like-modifiers during ischemic stress is regulated by microRNAs and confers robust tolerance to ischemia.

Lee YJ, Johnson KR, Hallenbeck JM - PLoS ONE (2012)

Bottom Line: We found that not only SUMO conjugation, but also global protein conjugation by other ULMs including NEDD8, ISG15, UFM1 and FUB1 were significantly increased in the brains of hibernating ground squirrels during torpor.By means of miRNA microarrays of ground squirrel brain samples (from active and torpor phase) we found that the miR-200 family (miR-200a,b,c/miR-141/miR-429) and the miR-182 family (miR-182/miR-183/miR-96) were among the most consistently depressed miRNAs in the brain during the torpor phase as compared to active animals.This is the first report to describe that the natural tolerance to brain ischemia in hibernators is linked to regulation by microRNAs of a broad range of ubiquitin-like modifiers.

View Article: PubMed Central - PubMed

Affiliation: Stroke Branch, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, Maryland, United States of America.

ABSTRACT
Hibernation torpor provides an excellent model of natural tolerance to ischemia. We have previously shown that massive global SUMOylation occurs during hibernation torpor in ground squirrels. We have also shown that overexpression of Ubc9, SUMO-1, or SUMO-2/3 provides protection against ischemic damage in cell lines and cortical neurons exposed to oxygen/glucose deprivation, and in mice exposed to middle cerebral artery occlusion. We have now extended our study to other Ubiquitin-Like-Modifiers (ULMs), which have multiple cellular functions during stress, in order to assess the possibility that they also have roles in tolerance to ischemia. We found that not only SUMO conjugation, but also global protein conjugation by other ULMs including NEDD8, ISG15, UFM1 and FUB1 were significantly increased in the brains of hibernating ground squirrels during torpor. By means of miRNA microarrays of ground squirrel brain samples (from active and torpor phase) we found that the miR-200 family (miR-200a,b,c/miR-141/miR-429) and the miR-182 family (miR-182/miR-183/miR-96) were among the most consistently depressed miRNAs in the brain during the torpor phase as compared to active animals. In addition, we showed that these miRNAs are involved in the expression of various ULM proteins and their global conjugation to proteins. We observed that inhibition of the miR-200 family and/or miR-182 family miRNA activities in SHSY5Y cells increases global protein conjugation by the above ULMs and makes these cells more tolerant to OGD-induced cell death. This is the first report to describe that the natural tolerance to brain ischemia in hibernators is linked to regulation by microRNAs of a broad range of ubiquitin-like modifiers.

Show MeSH

Related in: MedlinePlus

Protein Conjugation by various ULMs increases during hibernation torpor in the brains of 13-lined ground squirrels.(A) Representative Immunoblots of various ULMs in the brain samples from different stages of hibernation cycle. Arrow in each panel shows the molecular weight range of conjugates of the ULM indicated on top of the panel. a: ACR (active in the cold room); b: Ent (entrance); c: E-hib (early hibernation); d: L-hib (late hibernation); e:AR (arousal); f: IB (interabout). β-actin served as a loading control. Each immunoblot is representative of at least three different brain samples at each time point. (B) Quantitative analyses of the conjugates of various ULMs from three independent experiments. Cropped areas are shown by arrows; densities were measured, normalized by corresponding β-actin level, and shown as the ratio to ACR samples. Data represent the mean±SD of three independent experiments. **p<0.01, *p<0.05 compared to ACR.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3475703&req=5

pone-0047787-g001: Protein Conjugation by various ULMs increases during hibernation torpor in the brains of 13-lined ground squirrels.(A) Representative Immunoblots of various ULMs in the brain samples from different stages of hibernation cycle. Arrow in each panel shows the molecular weight range of conjugates of the ULM indicated on top of the panel. a: ACR (active in the cold room); b: Ent (entrance); c: E-hib (early hibernation); d: L-hib (late hibernation); e:AR (arousal); f: IB (interabout). β-actin served as a loading control. Each immunoblot is representative of at least three different brain samples at each time point. (B) Quantitative analyses of the conjugates of various ULMs from three independent experiments. Cropped areas are shown by arrows; densities were measured, normalized by corresponding β-actin level, and shown as the ratio to ACR samples. Data represent the mean±SD of three independent experiments. **p<0.01, *p<0.05 compared to ACR.

Mentions: Intensities of bands were analyzed by the Macintosh densitometry program ImageJ (NIH). For conjugate band analysis, the higher molecular weight area (indicated with arrows in Figure 1A) in each lane was cropped and analyzed.


Global protein conjugation by ubiquitin-like-modifiers during ischemic stress is regulated by microRNAs and confers robust tolerance to ischemia.

Lee YJ, Johnson KR, Hallenbeck JM - PLoS ONE (2012)

Protein Conjugation by various ULMs increases during hibernation torpor in the brains of 13-lined ground squirrels.(A) Representative Immunoblots of various ULMs in the brain samples from different stages of hibernation cycle. Arrow in each panel shows the molecular weight range of conjugates of the ULM indicated on top of the panel. a: ACR (active in the cold room); b: Ent (entrance); c: E-hib (early hibernation); d: L-hib (late hibernation); e:AR (arousal); f: IB (interabout). β-actin served as a loading control. Each immunoblot is representative of at least three different brain samples at each time point. (B) Quantitative analyses of the conjugates of various ULMs from three independent experiments. Cropped areas are shown by arrows; densities were measured, normalized by corresponding β-actin level, and shown as the ratio to ACR samples. Data represent the mean±SD of three independent experiments. **p<0.01, *p<0.05 compared to ACR.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3475703&req=5

pone-0047787-g001: Protein Conjugation by various ULMs increases during hibernation torpor in the brains of 13-lined ground squirrels.(A) Representative Immunoblots of various ULMs in the brain samples from different stages of hibernation cycle. Arrow in each panel shows the molecular weight range of conjugates of the ULM indicated on top of the panel. a: ACR (active in the cold room); b: Ent (entrance); c: E-hib (early hibernation); d: L-hib (late hibernation); e:AR (arousal); f: IB (interabout). β-actin served as a loading control. Each immunoblot is representative of at least three different brain samples at each time point. (B) Quantitative analyses of the conjugates of various ULMs from three independent experiments. Cropped areas are shown by arrows; densities were measured, normalized by corresponding β-actin level, and shown as the ratio to ACR samples. Data represent the mean±SD of three independent experiments. **p<0.01, *p<0.05 compared to ACR.
Mentions: Intensities of bands were analyzed by the Macintosh densitometry program ImageJ (NIH). For conjugate band analysis, the higher molecular weight area (indicated with arrows in Figure 1A) in each lane was cropped and analyzed.

Bottom Line: We found that not only SUMO conjugation, but also global protein conjugation by other ULMs including NEDD8, ISG15, UFM1 and FUB1 were significantly increased in the brains of hibernating ground squirrels during torpor.By means of miRNA microarrays of ground squirrel brain samples (from active and torpor phase) we found that the miR-200 family (miR-200a,b,c/miR-141/miR-429) and the miR-182 family (miR-182/miR-183/miR-96) were among the most consistently depressed miRNAs in the brain during the torpor phase as compared to active animals.This is the first report to describe that the natural tolerance to brain ischemia in hibernators is linked to regulation by microRNAs of a broad range of ubiquitin-like modifiers.

View Article: PubMed Central - PubMed

Affiliation: Stroke Branch, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, Maryland, United States of America.

ABSTRACT
Hibernation torpor provides an excellent model of natural tolerance to ischemia. We have previously shown that massive global SUMOylation occurs during hibernation torpor in ground squirrels. We have also shown that overexpression of Ubc9, SUMO-1, or SUMO-2/3 provides protection against ischemic damage in cell lines and cortical neurons exposed to oxygen/glucose deprivation, and in mice exposed to middle cerebral artery occlusion. We have now extended our study to other Ubiquitin-Like-Modifiers (ULMs), which have multiple cellular functions during stress, in order to assess the possibility that they also have roles in tolerance to ischemia. We found that not only SUMO conjugation, but also global protein conjugation by other ULMs including NEDD8, ISG15, UFM1 and FUB1 were significantly increased in the brains of hibernating ground squirrels during torpor. By means of miRNA microarrays of ground squirrel brain samples (from active and torpor phase) we found that the miR-200 family (miR-200a,b,c/miR-141/miR-429) and the miR-182 family (miR-182/miR-183/miR-96) were among the most consistently depressed miRNAs in the brain during the torpor phase as compared to active animals. In addition, we showed that these miRNAs are involved in the expression of various ULM proteins and their global conjugation to proteins. We observed that inhibition of the miR-200 family and/or miR-182 family miRNA activities in SHSY5Y cells increases global protein conjugation by the above ULMs and makes these cells more tolerant to OGD-induced cell death. This is the first report to describe that the natural tolerance to brain ischemia in hibernators is linked to regulation by microRNAs of a broad range of ubiquitin-like modifiers.

Show MeSH
Related in: MedlinePlus