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Delayed inflammatory mRNA and protein expression after spinal cord injury.

Byrnes KR, Washington PM, Knoblach SM, Hoffman E, Faden AI - J Neuroinflammation (2011)

Bottom Line: As p22PHOX and gp91PHOX are components of the NADPH oxidase enzyme, enzymatic activity and its role in SCI were assessed and NADPH oxidase activity was found to be significantly up-regulated through 6 months post-injury.Further, treating rats with the nonspecific, irreversible NADPH oxidase inhibitor diphenylene iodinium (DPI) reduced both lesion volume and expression of chronic gene cluster proteins one month after trauma.These data demonstrate that inflammation-related genes are chronically up-regulated after SCI and may contribute to further tissue loss.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Neuroscience, Georgetown University Medical Center, NW, Washington, DC (20057), USA. kbyrnes@usuhs.mil

ABSTRACT

Background: Spinal cord injury (SCI) induces secondary tissue damage that is associated with inflammation. We have previously demonstrated that inflammation-related gene expression after SCI occurs in two waves - an initial cluster that is acutely and transiently up-regulated within 24 hours, and a more delayed cluster that peaks between 72 hours and 7 days. Here we extend the microarray analysis of these gene clusters up to 6 months post-SCI.

Methods: Adult male rats were subjected to mild, moderate or severe spinal cord contusion injury at T9 using a well-characterized weight-drop model. Tissue from the lesion epicenter was obtained 4 hours, 24 hours, 7 days, 28 days, 3 months or 6 months post-injury and processed for microarray analysis and protein expression.

Results: Anchor gene analysis using C1qB revealed a cluster of genes that showed elevated expression through 6 months post-injury, including galectin-3, p22PHOX, gp91PHOX, CD53 and progranulin. The expression of these genes occurred primarily in microglia/macrophage cells and was confirmed at the protein level using both immunohistochemistry and western blotting. As p22PHOX and gp91PHOX are components of the NADPH oxidase enzyme, enzymatic activity and its role in SCI were assessed and NADPH oxidase activity was found to be significantly up-regulated through 6 months post-injury. Further, treating rats with the nonspecific, irreversible NADPH oxidase inhibitor diphenylene iodinium (DPI) reduced both lesion volume and expression of chronic gene cluster proteins one month after trauma.

Conclusions: These data demonstrate that inflammation-related genes are chronically up-regulated after SCI and may contribute to further tissue loss.

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Related in: MedlinePlus

Temporal profile patterns of the acute and delayed-expression cluster. Time post-injury and group are represented on the y-axis; specific genes are indicated on the x-axis. Gene expression of injured and sham-injured samples are shown for the lesion epicenter after mild, moderate and severe injuries. Note the increase in expression at 4 h post-injury in the acute-expression cluster, and the more delayed increase in intensity in the delayed-expression cluster compared to that in the sham-injured group. Cool colors represent decreased expression and warmer colors indicate higher expression relative to naïve controls (yellow).
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Figure 1: Temporal profile patterns of the acute and delayed-expression cluster. Time post-injury and group are represented on the y-axis; specific genes are indicated on the x-axis. Gene expression of injured and sham-injured samples are shown for the lesion epicenter after mild, moderate and severe injuries. Note the increase in expression at 4 h post-injury in the acute-expression cluster, and the more delayed increase in intensity in the delayed-expression cluster compared to that in the sham-injured group. Cool colors represent decreased expression and warmer colors indicate higher expression relative to naïve controls (yellow).

Mentions: Microarray analysis was performed 4 hours, 24 hours, 7 days, 14 days, 28 days, 3 months and 6 months after mild, moderate and severe spinal cord contusion injury at T9. Gene expression data was retrieved from Affymetrix high density oligonucleotide arrays of approximately 24,000 probe sets. Our previous paper [15] detailed the expression of genes associated with microglial function up to 7 days after SCI. Analysis of chronic expression demonstrated additional expression profiles expanding upon the previous data. In this study, anchor gene temporal clustering methods identified two temporally distinct gene clusters with a correlation r2 value of greater than 0.98 (Figure 1, Table 1).


Delayed inflammatory mRNA and protein expression after spinal cord injury.

Byrnes KR, Washington PM, Knoblach SM, Hoffman E, Faden AI - J Neuroinflammation (2011)

Temporal profile patterns of the acute and delayed-expression cluster. Time post-injury and group are represented on the y-axis; specific genes are indicated on the x-axis. Gene expression of injured and sham-injured samples are shown for the lesion epicenter after mild, moderate and severe injuries. Note the increase in expression at 4 h post-injury in the acute-expression cluster, and the more delayed increase in intensity in the delayed-expression cluster compared to that in the sham-injured group. Cool colors represent decreased expression and warmer colors indicate higher expression relative to naïve controls (yellow).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3198932&req=5

Figure 1: Temporal profile patterns of the acute and delayed-expression cluster. Time post-injury and group are represented on the y-axis; specific genes are indicated on the x-axis. Gene expression of injured and sham-injured samples are shown for the lesion epicenter after mild, moderate and severe injuries. Note the increase in expression at 4 h post-injury in the acute-expression cluster, and the more delayed increase in intensity in the delayed-expression cluster compared to that in the sham-injured group. Cool colors represent decreased expression and warmer colors indicate higher expression relative to naïve controls (yellow).
Mentions: Microarray analysis was performed 4 hours, 24 hours, 7 days, 14 days, 28 days, 3 months and 6 months after mild, moderate and severe spinal cord contusion injury at T9. Gene expression data was retrieved from Affymetrix high density oligonucleotide arrays of approximately 24,000 probe sets. Our previous paper [15] detailed the expression of genes associated with microglial function up to 7 days after SCI. Analysis of chronic expression demonstrated additional expression profiles expanding upon the previous data. In this study, anchor gene temporal clustering methods identified two temporally distinct gene clusters with a correlation r2 value of greater than 0.98 (Figure 1, Table 1).

Bottom Line: As p22PHOX and gp91PHOX are components of the NADPH oxidase enzyme, enzymatic activity and its role in SCI were assessed and NADPH oxidase activity was found to be significantly up-regulated through 6 months post-injury.Further, treating rats with the nonspecific, irreversible NADPH oxidase inhibitor diphenylene iodinium (DPI) reduced both lesion volume and expression of chronic gene cluster proteins one month after trauma.These data demonstrate that inflammation-related genes are chronically up-regulated after SCI and may contribute to further tissue loss.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Neuroscience, Georgetown University Medical Center, NW, Washington, DC (20057), USA. kbyrnes@usuhs.mil

ABSTRACT

Background: Spinal cord injury (SCI) induces secondary tissue damage that is associated with inflammation. We have previously demonstrated that inflammation-related gene expression after SCI occurs in two waves - an initial cluster that is acutely and transiently up-regulated within 24 hours, and a more delayed cluster that peaks between 72 hours and 7 days. Here we extend the microarray analysis of these gene clusters up to 6 months post-SCI.

Methods: Adult male rats were subjected to mild, moderate or severe spinal cord contusion injury at T9 using a well-characterized weight-drop model. Tissue from the lesion epicenter was obtained 4 hours, 24 hours, 7 days, 28 days, 3 months or 6 months post-injury and processed for microarray analysis and protein expression.

Results: Anchor gene analysis using C1qB revealed a cluster of genes that showed elevated expression through 6 months post-injury, including galectin-3, p22PHOX, gp91PHOX, CD53 and progranulin. The expression of these genes occurred primarily in microglia/macrophage cells and was confirmed at the protein level using both immunohistochemistry and western blotting. As p22PHOX and gp91PHOX are components of the NADPH oxidase enzyme, enzymatic activity and its role in SCI were assessed and NADPH oxidase activity was found to be significantly up-regulated through 6 months post-injury. Further, treating rats with the nonspecific, irreversible NADPH oxidase inhibitor diphenylene iodinium (DPI) reduced both lesion volume and expression of chronic gene cluster proteins one month after trauma.

Conclusions: These data demonstrate that inflammation-related genes are chronically up-regulated after SCI and may contribute to further tissue loss.

Show MeSH
Related in: MedlinePlus