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A critical role for pannexin-1 in activation of innate immune cells of the choroid plexus.

Maslieieva V, Thompson RJ - Channels (Austin) (2014)

Bottom Line: Here we have developed a novel technique for studying epiplexus cells in acutely isolated, live and intact choroid plexus.We show that epiplexus cells are potently activated by exogenous ATP, increasing their motility within the tissue.Furthermore, ATP acts at least in part through the P2X4 ionotropic purinergic receptor.

View Article: PubMed Central - PubMed

Affiliation: Hotchkiss Brain Institute; Department of Cell Biology and Anatomy; University of Calgary; Calgary, AB Canada.

ABSTRACT
Epiplexus cells are a population of innate immune cells in the choroid plexus of the brain ventricles. They are thought to contribute to the immune component of the blood-cerebrospinal-fluid-barrier (BCSFB). Here we have developed a novel technique for studying epiplexus cells in acutely isolated, live and intact choroid plexus. We show that epiplexus cells are potently activated by exogenous ATP, increasing their motility within the tissue. This ATP-induced chemokinesis required activation of pannexin-1 channels, which are expressed by the epithelial cells of the choroid plexus and not the epiplexus cells themselves. Furthermore, ATP acts at least in part through the P2X4 ionotropic purinergic receptor. Thus, the resident immune cells of the choroid plexus appear to be in communication with the epithelial cells through pannexin-1 channels.

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Figure 2. Extracellular ATP triggers chemokinesis of epiplexus cells. (A and D) Representation of the tracked paths superimposed on the original image under control conditions and in the presence of exogenous 100 µM ATP. Labels in the top right of the images represent the time relative to the start of the experiment (0 min). Note the 25 min was the end of the baseline and 120 min was the end of the experiment. Scale bar is 50 µm. Raw data showing the distance traveled by individual epiplexus cells in control (B) and in the presence of ATP (E). Each colored line represents an individual epiplexus cell. (B and E) Raw distance traveled during 5 min intervals; (C and F) normalized summative distance traveled.
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Figure 2: Figure 2. Extracellular ATP triggers chemokinesis of epiplexus cells. (A and D) Representation of the tracked paths superimposed on the original image under control conditions and in the presence of exogenous 100 µM ATP. Labels in the top right of the images represent the time relative to the start of the experiment (0 min). Note the 25 min was the end of the baseline and 120 min was the end of the experiment. Scale bar is 50 µm. Raw data showing the distance traveled by individual epiplexus cells in control (B) and in the presence of ATP (E). Each colored line represents an individual epiplexus cell. (B and E) Raw distance traveled during 5 min intervals; (C and F) normalized summative distance traveled.

Mentions: To test the responsiveness of epiplexus cells to purinergic signaling, we bath applied ATP. We reasoned that unlike focal applications, bath exposure to ATP would more closely mimic an infection or injury. The movement of epiplexus cells was first determined under baseline conditions (without exogenously applied ATP) by manually tracking the movement of somas at 5 min intervals (Fig. 2A and B; Video 1). Over a 95 min imaging period epiplexus cells were largely quiescent (Figs. 2and3; Video 1) with a mean normalized (i.e., baseline subtracted) movement of 0.05 ± 0.15 μm/5 min (n = 124 cells from 5 CPs). Note that in Figure 2C and F the summative distance (i.e., running sum of distance traveled at 5 min intervals) could appear negative if the cells were active during the early baseline but became subsequently quiescent (see Materials and Methods).


A critical role for pannexin-1 in activation of innate immune cells of the choroid plexus.

Maslieieva V, Thompson RJ - Channels (Austin) (2014)

Figure 2. Extracellular ATP triggers chemokinesis of epiplexus cells. (A and D) Representation of the tracked paths superimposed on the original image under control conditions and in the presence of exogenous 100 µM ATP. Labels in the top right of the images represent the time relative to the start of the experiment (0 min). Note the 25 min was the end of the baseline and 120 min was the end of the experiment. Scale bar is 50 µm. Raw data showing the distance traveled by individual epiplexus cells in control (B) and in the presence of ATP (E). Each colored line represents an individual epiplexus cell. (B and E) Raw distance traveled during 5 min intervals; (C and F) normalized summative distance traveled.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4048302&req=5

Figure 2: Figure 2. Extracellular ATP triggers chemokinesis of epiplexus cells. (A and D) Representation of the tracked paths superimposed on the original image under control conditions and in the presence of exogenous 100 µM ATP. Labels in the top right of the images represent the time relative to the start of the experiment (0 min). Note the 25 min was the end of the baseline and 120 min was the end of the experiment. Scale bar is 50 µm. Raw data showing the distance traveled by individual epiplexus cells in control (B) and in the presence of ATP (E). Each colored line represents an individual epiplexus cell. (B and E) Raw distance traveled during 5 min intervals; (C and F) normalized summative distance traveled.
Mentions: To test the responsiveness of epiplexus cells to purinergic signaling, we bath applied ATP. We reasoned that unlike focal applications, bath exposure to ATP would more closely mimic an infection or injury. The movement of epiplexus cells was first determined under baseline conditions (without exogenously applied ATP) by manually tracking the movement of somas at 5 min intervals (Fig. 2A and B; Video 1). Over a 95 min imaging period epiplexus cells were largely quiescent (Figs. 2and3; Video 1) with a mean normalized (i.e., baseline subtracted) movement of 0.05 ± 0.15 μm/5 min (n = 124 cells from 5 CPs). Note that in Figure 2C and F the summative distance (i.e., running sum of distance traveled at 5 min intervals) could appear negative if the cells were active during the early baseline but became subsequently quiescent (see Materials and Methods).

Bottom Line: Here we have developed a novel technique for studying epiplexus cells in acutely isolated, live and intact choroid plexus.We show that epiplexus cells are potently activated by exogenous ATP, increasing their motility within the tissue.Furthermore, ATP acts at least in part through the P2X4 ionotropic purinergic receptor.

View Article: PubMed Central - PubMed

Affiliation: Hotchkiss Brain Institute; Department of Cell Biology and Anatomy; University of Calgary; Calgary, AB Canada.

ABSTRACT
Epiplexus cells are a population of innate immune cells in the choroid plexus of the brain ventricles. They are thought to contribute to the immune component of the blood-cerebrospinal-fluid-barrier (BCSFB). Here we have developed a novel technique for studying epiplexus cells in acutely isolated, live and intact choroid plexus. We show that epiplexus cells are potently activated by exogenous ATP, increasing their motility within the tissue. This ATP-induced chemokinesis required activation of pannexin-1 channels, which are expressed by the epithelial cells of the choroid plexus and not the epiplexus cells themselves. Furthermore, ATP acts at least in part through the P2X4 ionotropic purinergic receptor. Thus, the resident immune cells of the choroid plexus appear to be in communication with the epithelial cells through pannexin-1 channels.

Show MeSH
Related in: MedlinePlus