Limits...
Gene expression profiling of vasoregression in the retina--involvement of microglial cells.

Feng Y, Wang Y, Li L, Wu L, Hoffmann S, Gretz N, Hammes HP - PLoS ONE (2011)

Bottom Line: Of the 157 genes regulated more than twofold, the MHC class II invariant chain CD74 yielded the strongest upregulation, and was allocated to activated microglial cells close to the vessels undergoing vasoregression.Pathway clustering identified genes of the immune system including inflammatory signaling, and components of the complement cascade upregulated during vasoregression.Together, our data suggest that microglial cells involved in retinal immune response participate in the initiation of vasoregression in the retina.

View Article: PubMed Central - PubMed

Affiliation: 5 Medical Department, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany.

ABSTRACT
Vasoregression is a hallmark of vascular eye diseases but the mechanisms involved are still largely unknown. We have recently characterized a rat ciliopathy model which develops primary photoreceptor degeneration and secondary vasoregression. To improve the understanding of secondary vasoregression in retinal neurodegeneration, we used microarray techniques to compare gene expression profiles in this new model before and after retinal vasoregression. Differential gene expression was validated by quantitative RT-PCR, Western blot and immunofluorescence. Of the 157 genes regulated more than twofold, the MHC class II invariant chain CD74 yielded the strongest upregulation, and was allocated to activated microglial cells close to the vessels undergoing vasoregression. Pathway clustering identified genes of the immune system including inflammatory signaling, and components of the complement cascade upregulated during vasoregression. Together, our data suggest that microglial cells involved in retinal immune response participate in the initiation of vasoregression in the retina.

Show MeSH

Related in: MedlinePlus

Activation of microglial cells in TGR retinas.Vessels and microglial cells are visualized by staining with Lectin (blue) and CD11b (green), respectively. CD74 (red) is expressed in microglial cells (A–D). Furthermore, CD74 (green) is not detected in pericytes as demonstrated by the staining with NG2 (red), a pericyte marker (E–H). Moreover, microglial cells expressing CD74 were found to be close to regressive capillary (I–L). Arrows in A–D: colocalization of CD74 and CD11b; arrows in E–H: pericyte; arrowheads in E–H: CD74 positive microglial cell. Arrows in I–L: regressive vessel.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3040753&req=5

pone-0016865-g006: Activation of microglial cells in TGR retinas.Vessels and microglial cells are visualized by staining with Lectin (blue) and CD11b (green), respectively. CD74 (red) is expressed in microglial cells (A–D). Furthermore, CD74 (green) is not detected in pericytes as demonstrated by the staining with NG2 (red), a pericyte marker (E–H). Moreover, microglial cells expressing CD74 were found to be close to regressive capillary (I–L). Arrows in A–D: colocalization of CD74 and CD11b; arrows in E–H: pericyte; arrowheads in E–H: CD74 positive microglial cell. Arrows in I–L: regressive vessel.

Mentions: Next, we identified by immunofluorescence that CD74 was expressed in cells close to both, the superficial and deep capillary layers in SD rats. In contrast, CD74 positive cells were located predominantly around the deep capillary in TGR rats of one month of age. The strongest and most obvious accumulation of CD74-positive cells was found in TGR rats of three months in the vicinity of the deep capillary layers. CD74 positive cells were either localized on or closed to the vessels or in the inter-vascular spaces with prolonged end feet spanning vessels. The morphology of these cells identified them as microglial cells which were further confirmed by co-immunostaining with microglial marker CD11b and Iba-1 (Figure 6A, B, C, D and Figure S1). CD74 was expressed predominantly in the membrane of cell soma and dot-like in the processes of microglial cells, whereas CD11b labelled strongly all processes of microglial cells. Even though CD74-positive microglial cells were localised close to vessels and some even seemed morphologiocally like pericytes, immunofluorescence staining revealed no colocalisation between CD74 positive microglia cells and pericytes labelled with pericyte-specific marker NG2 (Figure 6E, F, G, H). 66% CD74 positive microglial cells were close to the capillaries. Close correlation between CD74 positive microglial cells and regressive vessels was noted in 3-month TGR retinas (Figure 6I, J, K, L).


Gene expression profiling of vasoregression in the retina--involvement of microglial cells.

Feng Y, Wang Y, Li L, Wu L, Hoffmann S, Gretz N, Hammes HP - PLoS ONE (2011)

Activation of microglial cells in TGR retinas.Vessels and microglial cells are visualized by staining with Lectin (blue) and CD11b (green), respectively. CD74 (red) is expressed in microglial cells (A–D). Furthermore, CD74 (green) is not detected in pericytes as demonstrated by the staining with NG2 (red), a pericyte marker (E–H). Moreover, microglial cells expressing CD74 were found to be close to regressive capillary (I–L). Arrows in A–D: colocalization of CD74 and CD11b; arrows in E–H: pericyte; arrowheads in E–H: CD74 positive microglial cell. Arrows in I–L: regressive vessel.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3040753&req=5

pone-0016865-g006: Activation of microglial cells in TGR retinas.Vessels and microglial cells are visualized by staining with Lectin (blue) and CD11b (green), respectively. CD74 (red) is expressed in microglial cells (A–D). Furthermore, CD74 (green) is not detected in pericytes as demonstrated by the staining with NG2 (red), a pericyte marker (E–H). Moreover, microglial cells expressing CD74 were found to be close to regressive capillary (I–L). Arrows in A–D: colocalization of CD74 and CD11b; arrows in E–H: pericyte; arrowheads in E–H: CD74 positive microglial cell. Arrows in I–L: regressive vessel.
Mentions: Next, we identified by immunofluorescence that CD74 was expressed in cells close to both, the superficial and deep capillary layers in SD rats. In contrast, CD74 positive cells were located predominantly around the deep capillary in TGR rats of one month of age. The strongest and most obvious accumulation of CD74-positive cells was found in TGR rats of three months in the vicinity of the deep capillary layers. CD74 positive cells were either localized on or closed to the vessels or in the inter-vascular spaces with prolonged end feet spanning vessels. The morphology of these cells identified them as microglial cells which were further confirmed by co-immunostaining with microglial marker CD11b and Iba-1 (Figure 6A, B, C, D and Figure S1). CD74 was expressed predominantly in the membrane of cell soma and dot-like in the processes of microglial cells, whereas CD11b labelled strongly all processes of microglial cells. Even though CD74-positive microglial cells were localised close to vessels and some even seemed morphologiocally like pericytes, immunofluorescence staining revealed no colocalisation between CD74 positive microglia cells and pericytes labelled with pericyte-specific marker NG2 (Figure 6E, F, G, H). 66% CD74 positive microglial cells were close to the capillaries. Close correlation between CD74 positive microglial cells and regressive vessels was noted in 3-month TGR retinas (Figure 6I, J, K, L).

Bottom Line: Of the 157 genes regulated more than twofold, the MHC class II invariant chain CD74 yielded the strongest upregulation, and was allocated to activated microglial cells close to the vessels undergoing vasoregression.Pathway clustering identified genes of the immune system including inflammatory signaling, and components of the complement cascade upregulated during vasoregression.Together, our data suggest that microglial cells involved in retinal immune response participate in the initiation of vasoregression in the retina.

View Article: PubMed Central - PubMed

Affiliation: 5 Medical Department, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany.

ABSTRACT
Vasoregression is a hallmark of vascular eye diseases but the mechanisms involved are still largely unknown. We have recently characterized a rat ciliopathy model which develops primary photoreceptor degeneration and secondary vasoregression. To improve the understanding of secondary vasoregression in retinal neurodegeneration, we used microarray techniques to compare gene expression profiles in this new model before and after retinal vasoregression. Differential gene expression was validated by quantitative RT-PCR, Western blot and immunofluorescence. Of the 157 genes regulated more than twofold, the MHC class II invariant chain CD74 yielded the strongest upregulation, and was allocated to activated microglial cells close to the vessels undergoing vasoregression. Pathway clustering identified genes of the immune system including inflammatory signaling, and components of the complement cascade upregulated during vasoregression. Together, our data suggest that microglial cells involved in retinal immune response participate in the initiation of vasoregression in the retina.

Show MeSH
Related in: MedlinePlus