Functional implication of Dp71 in osmoregulation and vascular permeability of the retina.
Functional alterations of Müller cells, the principal glia of the retina, are an early hallmark of most retina diseases and contribute to their further progression. The molecular mechanisms of these reactive Müller cell alterations, resulting in disturbed retinal homeostasis, remain largely unknown. Here we show that experimental detachment of mouse retina induces mislocation of the inwardly rectifying potassium channels (Kir4.1) and a downregulation of the water channel protein (AQP4) in Müller cells. These alterations are associated with a strong decrease of Dp71, a cytoskeleton protein responsible for the localization and the clustering of Kir4.1 and AQP4. Partial (in detached retinas) or total depletion of Dp71 in Müller cells (in Dp71-null mice) impairs the capability of volume regulation of Müller cells under osmotic stress. The abnormal swelling of Müller cells In Dp71-null mice involves the action of inflammatory mediators. Moreover, we investigated whether the alterations in Müller cells of Dp71-null mice may interfere with their regulatory effect on the blood-retina barrier. In the absence of Dp71, the retinal vascular permeability was increased as compared to the controls. Our results reveal that Dp71 is crucially implicated in the maintenance of potassium homeostasis, in transmembraneous water transport, and in the Müller cell-mediated regulation of retinal vascular permeability. Furthermore, our data provide novel insights into the mechanisms of retinal homeostasis provided by Müller cells under normal and pathological conditions.
Sene
Abdoulaye
A
Institut National de la Sante et de la Recherche Médicale, UMR_S 968, Institut de la Vision, Paris, France.
Tadayoni
Ramin
R
Pannicke
Thomas
T
Wurm
Antje
A
El Mathari
Brahim
B
Benard
Romain
R
Roux
Michel Joseph
MJ
Yaffe
David
D
Mornet
Dominique
D
Reichenbach
Andreas
A
Sahel
Jose-Alain
JA
Rendon
Alvaro
A
D000818:Animals; D051401:Aquaporin 4 / Q000096:biosynthesis; D002199:Capillary Permeability / Q000235:genetics; D016189:Dystrophin / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004594:Electrophysiology; D005911:Gliosis / Q000473:pathology; D006706:Homeostasis; D051379:Mice; D008810:Mice, Inbred C57BL; D011188:Potassium / Q000378:metabolism; D024661:Potassium Channels, Inwardly Rectifying / Q000096:biosynthesis; D012160:Retina / Q000378:metabolism*; D012162:Retinal Degeneration / Q000378:metabolism; D012171:Retinal Vessels / Q000378:metabolism; D014882:Water-Electrolyte Balance / Q000235:genetics*; D000098854:Kcnj10 Channel
C496031:Aqp4 protein, mouse; D051401:Aquaporin 4; D016189:Dystrophin; D000098854:Kcnj10 Channel; D024661:Potassium Channels, Inwardly Rectifying; C085339:apo-dystrophin 1; D011188:Potassium