Activating Transcription Factor 3 (ATF3) Protects Retinal Ganglion Cells and Promotes Functional Preservation After Optic Nerve Crush

Abstract

PURPOSE.To investigate the possible role of activating transcription factor 3 (ATF3) in retinal ganglion cell (RGC) neuroprotection and optic nerve regeneration after optic nerve crush (ONC). METHODS.Overexpression of proteins of interest (ATF3, phosphatase and tensin homolog [PTEN], placental alkaline phosphatase, green fluorescent protein) in the retina was achieved by intravitreal injections of recombinant adenovirus-associated viruses (rAAVs) expressing corresponding proteins. The number of RGCs and αRGCs was evaluated by immunostaining retinal sections and whole-mount retinas with antibodies against RNA binding protein with multiple splicing (RBPMS) and osteopontin, respectively. Axonal regeneration was assessed via fluorophore-coupled cholera toxin subunit B labeling. RGC function was evaluated by recording positive scotopic threshold response. RESULTS.The level of ATF3 is preferentially elevated in osteopontin + /RBPMS + αRGCs following ONC. Overexpression of ATF3 by intravitreal injection of rAAV 2 weeks before ONC promoted RBPMS + RGC survival and preserved RGC function as assessed by positive scotopic threshold response recordings 2 weeks after ONC. However, overexpression of ATF3 and simultaneous downregulation of PTEN, a negative regulator of the mTOR pathway, combined with ONC, only moderately promoted short distance RGC axon regeneration (200 μm from the lesion site) but did not provide additional RGC neuroprotection compared with PTEN downregulation alone. CONCLUSIONS.These results reveal a neuroprotective effect of ATF3 in the retina following injury and identify ATF3 as a promising agent for potential treatments of optic neuropathies.

Laser Capture Microdissection-Based RNA Microsequencing Reveals Optic Nerve Crush-Related Early mRNA Alterations in Retinal Ganglion Cell Layer

“… 16 – 18 More recently, Atf3 was reported to protects RGC and promote visual function after ONC. 19 Our results implied that Atf3 and axonal regeneration started in the early stage after ONC.…”

A Comparative Analysis of Reactive Müller Glia Gene Expression After Light Damage and microRNA-Depleted Müller Glia—Focus on microRNAs

“…Atf3 increases various downstream targets such as Ccl2 (which is also upregulated after light damage Figure 4E ), induces cell proliferation but also apoptosis (Ku and Cheng, 2020 ). In the retina, it has been described in fish regeneration (Saul et al, 2010 ), as a neuroprotective factor after optic nerve crush in murine neurons (Kole et al, 2020 ) and as a cyto-protective factor in astrocytes after oxidative stress induction (Kim et al, 2010 ). For MG, Atf3 is suggested to be regulated by tumor suppressor protein p53 (Ueki et al, 2012 ).…”

Retinal ganglion cell survival after severe optic nerve injury is modulated by crosstalk between JAK/STAT signaling and innate immune responses in the zebrafish retina

“…We reasoned that neuroprotective factors would be upregulated upon ONT, and the upregulated DEG group included stat3, irf9, sox11b, lepr, and socs3b , which encode components/regulators of the JAK/STAT signaling pathway (Fig. 2C; (Villarino et al, 2015)), in addition to other neuroprotective and pro-regenerative genes such as gap43 (Chung et al, 2020), atf3 (Kole et al, 2020), and atoh7 (Brodie-Kommit et al, 2021). Moreover, the interferon regulatory factor genes, irf9 and irf1b (Langevin et al, 2013), and the chemokine receptor, cxcr4b (García-Cuesta et al, 2019), were also upregulated, suggesting activation of innate immune responses in RGCs after ONT.…”