The purpose of this study was to examine the toxicity and side effects of a recombinant adeno-associated virus 8 (AAV8) vector, aimed to treat cyclic nucleotide gated channel alpha 3 (CNGA3)-linked achromatopsia, after a single subretinal administration in cynomolgus macaques. Animals were followed in two studies: a 13-week study with 22 animals and a 28-day study with 12 animals. Both groups were divided into subgroups receiving either vehicle only, a low (1 × 1011 vector genomes (vg)), or a high dose (1 × 1012 vg) of rAAV.hCNGA3. In the 13-week study, an extra group received single high-dose intravitreal injections. Here we present the group results of the histological examinations carried out after necropsy from the 28-day study, the retinal functional (electroretinography) in the 13-week study, and clinical observations from both studies. Treatment-related adverse effects were not found, and parameter changes were mostly related to the surgical procedure. The treatment of achromatopsia with rAAV.hCNGA3 is therefore deemed safe to apply to humans.
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References
1.
ThiadensAA, SomervuoV, van den BornLI, et al.Progressive loss of cones in achromatopsia: an imaging study using spectral-domain optical coherence tomography. Invest Ophthalmol Vis Sci, 2010; 51:5952–5957.
2.
SharpeLT, StockmanA, JägleH, et al.Opsin genes, cone photopigments, color vision, and color blindness. In: GegenfurtnerKR, SharpeLT, eds. Color Vision: From Genes to Perception. Cambridge, UK: Cambridge University Press, 1999:3–52.
3.
KohlS, BaumannB, BroghammerM, et al.Mutations in the CNGB3 gene encoding the beta-subunit of the cone photoreceptor cGMP-gated channel are responsible for achromatopsia (ACHM3) linked to chromosome 8q21. Hum Mol Genet, 2000; 9:2107–2116.
4.
KohlS, VarsanyiB, AntunesGA, et al.CNGB3 mutations account for 50% of all cases with autosomal recessive achromatopsia. Eur J Hum Genet, 2005; 13:302–308.
5.
ThiadensAA, RoosingS, CollinRW, et al.Comprehensive analysis of the achromatopsia genes CNGA3 and CNGB3 in progressive cone dystrophy. Ophthalmol, 2010; 117:825–830 e821.
6.
ZelingerL, CideciyanAV, KohlS, et al.Genetics and disease expression in the CNGA3 form of achromatopsia: Steps on the path to gene therapy. Ophthalmol, 2015; 122:997–1007.
7.
KohlS, MarxT, GiddingsI, et al.Total colourblindness is caused by mutations in the gene encoding the alpha-subunit of the cone photoreceptor cGMP-gated cation channel. Nat Genet, 1998; 19:257–259.
8.
WissingerB, GamerD, JagleH, et al.CNGA3 mutations in hereditary cone photoreceptor disorders. Am J Hum Genet, 2001; 69:722–737.
9.
LiS, HuangL, XiaoX, et al.Identification of CNGA3 mutations in 46 families: Common cause of achromatopsia and cone-rod dystrophies in Chinese patients. JAMA Ophthalmol, 2014; 132:1076–1083.
10.
LiangX, DongF, LiH, et al.Novel CNGA3 mutations in Chinese patients with achromatopsia. Br J Ophthalmol, 2015; 99:571–576.
11.
AligianisIA, ForshewT, JohnsonS, et al.Mapping of a novel locus for achromatopsia (ACHM4) to 1p and identification of a germline mutation in the alpha subunit of cone transducin (GNAT2). J Med Genet, 2002; 39:656–660.
12.
KohlS, BaumannB, RosenbergT, et al.Mutations in the cone photoreceptor G-protein alpha-subunit gene GNAT2 in patients with achromatopsia. Am J Hum Genet, 2002; 71:422–425.
13.
MichaelidesM, AligianisIA, HolderGE, et al.Cone dystrophy phenotype associated with a frameshift mutation (M280fsX291) in the alpha-subunit of cone specific transducin (GNAT2). Br J Ophthalmol, 2003; 87:1317–1320.
14.
PinaAL, BaumertU, LoyerM, et al.A three base pair deletion encoding the amino acid (lysine-270) in the alpha-cone transducin gene. Mol Vis, 2004; 10:265–271.
15.
RosenbergT, BaumannB, KohlS, et al.Variant phenotypes of incomplete achromatopsia in two cousins with GNAT2 gene mutations. Invest Ophthalmol Vis Sci, 2004; 45:4256–4262.
16.
ChangB, GrauT, DangelS, et al.A homologous genetic basis of the murine cpfl1 mutant and human achromatopsia linked to mutations in the PDE6C gene. Proc Natl Acad Sci U S A, 2009; 106:19581–19586.
17.
ThiadensAA, den HollanderAI, RoosingS, et al.Homozygosity mapping reveals PDE6C mutations in patients with early-onset cone photoreceptor disorders. Am J Hum Genet, 2009; 85:240–247.
18.
OuechtatiF, MerdassiA, BouyacoubY, et al.Clinical and genetic investigation of a large Tunisian family with complete achromatopsia: identification of a new nonsense mutation in GNAT2 gene. J Hum Genet, 2011; 56:22–28.
19.
GrauT, ArtemyevNO, RosenbergT, et al.Decreased catalytic activity and altered activation properties of PDE6C mutants associated with autosomal recessive achromatopsia. Hum Mol Genet, 2011; 20:719–730.
20.
KohlS, CoppietersF, MeireF, et al.A nonsense mutation in PDE6H causes autosomal-recessive incomplete achromatopsia. Am J Hum Genet, 2012; 91:527–532.
21.
HuangL, ZhangQ, LiS, et al.Exome sequencing of 47 chinese families with cone-rod dystrophy: mutations in 25 known causative genes. PLoS One, 2013; 8:e65546.
22.
AnsarM, Santos-CortezRL, SaqibMA, et al.Mutation of ATF6 causes autosomal recessive achromatopsia. Hum Genet, 2015; 134:941–950.
23.
KohlS, ZoborD, ChiangWC, et al.Mutations in the unfolded protein response regulator ATF6 cause the cone dysfunction disorder achromatopsia. Nat Genet, 2015; 47:757–765.
24.
XuM, GelowaniV, EblimitA, et al.ATF6 is mutated in early onset photoreceptor degeneration with macular involvement. Invest Ophthalmol Vis Sci, 2015; 56:3889–3895.
25.
ZeinWM, JeffreyBG, WileyHE, et al.CNGB3-achromatopsia clinical trial with CNTF: Diminished rod pathway responses with no evidence of improvement in cone function. Invest Ophthalmol Vis Sci, 2014; 55:6301–6308.
26.
MichalakisS, MuhlfriedelR, TanimotoN, et al.Restoration of cone vision in the CNGA3-/- mouse model of congenital complete lack of cone photoreceptor function. Mol Ther, 2010; 18:2057–2063.
27.
DuW, TaoY, DengWT, et al.Vitreal delivery of AAV vectored Cnga3 restores cone function in CNGA3-/-/Nrl-/- mice, an all-cone model of CNGA3 achromatopsia. Hum Mol Genet, 2015; 24:3699–3707.
28.
SeitzIP, MichalakisS, WilhelmB, et al.Superior retinal gene transfer and biodistribution profile of subretinal versus intravitreal delivery of AAV8 in nonhuman primates. Invest Ophthalmol Vis Sci, 2017; 58:5792–5801.
29.
ReichelFF, PetersT, WilhelmB, et al.Humoral immune response after intravitreal but not after subretinal AAV8 in primates and patients. Invest Ophthalmol Vis Sci, 2018; 59:1910–1915.
30.
ReichelFF, DauletbekovDL, KleinR, et al.AAV8 can induce innate and adaptive immune response in the primate eye. Mol Ther, 2017; 25:2648–2660.
31.
KimS-D, Nao iN, MaruiwaF, et al.Electrical responses from locally detached retina and its recovery after reattachment. Ophthalmologica, 1996:195–199.
32.
KimB-J, BraunTA, WordingerRJ, et al.Progressive morphological changes and impaired retinal function associated with temporal regulation of gene expression after retinal ischemia/reperfusion injury in mice. Mol Neurodegener, 2013; 8:21–21.
33.
MaclachlanTK, LukasonM, CollinsM, et al.Preclinical safety evaluation of AAV2-sFLT01- a gene therapy for age-related macular degeneration. Mol Ther, 2011; 19:326–334.
34.
NorkTM, MurphyCJ, KimCB, et al.Functional and anatomic consequences of subretinal dosing in the cynomolgus macaque. Arch Ophthalmol, 2012; 130:65–75.
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