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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

mRNA and protein expression profile of progranulin after spinal cord injury. Expression of progranulin was identified in the microarray and followed the expression profile of the delayed-expression cluster. Expression of progranulin peaked at 7 days post-injury and remained up-regulated through the end of the study (A). Protein expression was confirmed using immunohistochemistry at 28 days post-injury. Sham-injured tissue showed no progranulin positive cells at the lesion site (B). Injured tissue, however showed a large number of progranulin-positive cells (B). Double-labeling with Iba-1 (C) and NeuN (D) showed correlation of expression in microglia and neurons. Size bar = 200 μm (B), 100 μm (C, D).
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Figure 5: mRNA and protein expression profile of progranulin after spinal cord injury. Expression of progranulin was identified in the microarray and followed the expression profile of the delayed-expression cluster. Expression of progranulin peaked at 7 days post-injury and remained up-regulated through the end of the study (A). Protein expression was confirmed using immunohistochemistry at 28 days post-injury. Sham-injured tissue showed no progranulin positive cells at the lesion site (B). Injured tissue, however showed a large number of progranulin-positive cells (B). Double-labeling with Iba-1 (C) and NeuN (D) showed correlation of expression in microglia and neurons. Size bar = 200 μm (B), 100 μm (C, D).

Mentions: Immunolabeling also confirmed the expression profile observed in the microarray for progranulin (Figure 5A). Progranulin was markedly increased in injured tissue at 28 days post-injury in contrast to sham-injured tissue (Figure 5B). Double-immunolabeling demonstrated that Iba-1 positive microglia/macrophages expressed progranulin (Figure 5C). However, some neurons were also positive for progranulin, as demonstrated by NeuN/progranulin positive cells (Figure 5D). Progranulin was not found in GFAP positive cells, however (data not shown).


Delayed inflammatory mRNA and protein expression after spinal cord injury.

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

mRNA and protein expression profile of progranulin after spinal cord injury. Expression of progranulin was identified in the microarray and followed the expression profile of the delayed-expression cluster. Expression of progranulin peaked at 7 days post-injury and remained up-regulated through the end of the study (A). Protein expression was confirmed using immunohistochemistry at 28 days post-injury. Sham-injured tissue showed no progranulin positive cells at the lesion site (B). Injured tissue, however showed a large number of progranulin-positive cells (B). Double-labeling with Iba-1 (C) and NeuN (D) showed correlation of expression in microglia and neurons. Size bar = 200 μm (B), 100 μm (C, D).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 5: mRNA and protein expression profile of progranulin after spinal cord injury. Expression of progranulin was identified in the microarray and followed the expression profile of the delayed-expression cluster. Expression of progranulin peaked at 7 days post-injury and remained up-regulated through the end of the study (A). Protein expression was confirmed using immunohistochemistry at 28 days post-injury. Sham-injured tissue showed no progranulin positive cells at the lesion site (B). Injured tissue, however showed a large number of progranulin-positive cells (B). Double-labeling with Iba-1 (C) and NeuN (D) showed correlation of expression in microglia and neurons. Size bar = 200 μm (B), 100 μm (C, D).
Mentions: Immunolabeling also confirmed the expression profile observed in the microarray for progranulin (Figure 5A). Progranulin was markedly increased in injured tissue at 28 days post-injury in contrast to sham-injured tissue (Figure 5B). Double-immunolabeling demonstrated that Iba-1 positive microglia/macrophages expressed progranulin (Figure 5C). However, some neurons were also positive for progranulin, as demonstrated by NeuN/progranulin positive cells (Figure 5D). Progranulin was not found in GFAP positive cells, however (data not shown).

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