Trilogy Development of Proopiomelanocortin Neurons From Embryonic to Adult Stages in the Mice Retina

Abstract

Proopiomelanocortin-positive amacrine cells (POMC ACs) were first discovered in adult mouse retinas in 2010; however, the development of POMC-ACs has not been studied. We bred POMC-EGFP mice to label POMC-positive cells and investigated the development of POMC neurons from embryonic to adult stages. We found that POMC neuron development is mainly divided into three stages: the embryonic stage, the closed-eye stage, and the open-eye stage. Each stage has unique characteristics. In the embryonic stage, POMC neurons appeared in the retina at about E13. There was a cell number developmental peak at E15, followed by a steep decline at E16. POMC neurons showed a large soma and increased spine numbers at the closed-eye stage, and two dendritic sublaminas formed in the inner plexiform layer (IPL). The appearance and increased soma size and dendrite numbers did not occur continuously in space. We found that the soma number was asymmetric between the superior and inferior retinas according to the developmental topographic map. Density peaked in the superior retina, which existed persistently in the retinal ganglion cell layer (GCL), but disappeared from the inner nuclear layer (INL) at about P6. At the same time, the soma distribution in the INL was the most regular. At the open-eye stage, the development of POMC neurons was nearly stable only with only an increase in the IPL width, which increased the soma–dendrite distance.

Characterization of Retinal VIP-Amacrine Cell Development During the Critical Period

“…3 c1–c3, f1–f3). This indicated that YFP labeled the dendritic spines of VIP-YFP-ACs, as reported previously (Zhang et al 2021b ). With the spot function of Imaris, we evaluated the spine development of VIP-ACs (Fig.…”

“…In mice, adulthood usually refers to ages greater than six weeks, and in our experiment, we indeed observed a decrease in total retinal VIP levels by WB. The increasing trend in density for VIP-ACs was not the same as that observed for proopiomelanocortin (POMC)-ACs (Zhang et al 2021b ). The POMC-AC density peaked slightly earlier than the VIP-AC density, i.e., at P12.…”

“…Immunofluorescence staining was performed as described in our previous work (Zhang et al 2021b ). In short, after anesthetization, eyeballs were collected, the cornea, iris and lens were removed, then fixed, dehydrated with 30% (w/v) sucrose solution, and cut into 15-µm-thick cryosections.…”

“…The number of somas was quantified in 20× sections using ImageJ (Fiji) software. We used the spot function of Imaris 9.0.1 for masking and to determine the spine number as previously described (Zhang et al 2021b ). Electrophysiological recordings were analyzed using MiniAnalysis (Synaptosoft, Leonia, NJ, USA) and Igor 4.0 (WaveMetrics, Lake Oswego, OR, USA).…”

Functions of retinal astrocytes and Müller cells in mammalian myopia

“…We performed this as previously described from our group [ 16 ]. Briefly, the mice were anesthetized with pentobarbitone (50 mg/kg, intraperitoneal), then myocardial perfusion was performed and the eyeballs were removed and fixed for two hours at 4℃.…”