Abstract
Purpose :
Tmem30a acts as the beta-subunit of most P4-ATPases and participates in ATP-dependent phospholipid transport to maintain the asymmetric distribution phosphatidylserine on the plasma membrane. Tmem30a is abundantly expressed in rod bipolar cells (RBCs) in the retina, yet the physiological function of Tmem30a in these cells is poorly understood. To elucidate the roles of Tmem30a in visual processing in the eye, we examined the effect of genetic deletion of Tmem30a in RBCs on the visual function and on pathological changes in the mouse.
Methods :
Pcp2-Cre mice was crossed with Tmem30a transgenic mice to yield Tmem30a-RBCKO progenies. Scotopic and photopic Electroretinograms were recorded from wild-type (WT) and knockout (KO) mice to evaluate the function of RBCs in the retina. Histological study was carried out to verify the RBC loss in inner nuclear layer (INL). Immunofluorescent labeling of several antibodies was performed on WT and KO retina to reveal pathological alterations caused by Tmem30a deficiency.
Results :
Cre-mediated recombination in Pcp2-Cre line led to Tmem30a deficiency in RBCs. ERG recordings under scotopic condition indicated that the amplitude of b-wave was markedly decreased in KO mice. Immunohistochemistry using RBC specific marker PKCα revealed that the aberrant bipolar cell dendritic fibers extended into the outer nuclear layer (ONL) at the early stage of degeneration in KO retina. H&E staining of retinas from 12-month-old mice verified that the number of bipolar cell per row in INL was reduced in KO retina compared with that of control. Activated astrocytes detected in 12-month-old KO mice retina by immunostaining with GFAP suggested severe glial reaction.
Conclusions :
Our data demonstrated that Tmem30a plays essential roles in RBC function and survival.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.