Atoh1 expression levels define the fate of rat cochlear nonsensory epithelial cells in vitro.
Atonal homolog 1 (Atoh1) is a basic helix‑loop‑helix transcription factor that is essential for inner ear hair cell differentiation. Previous studies have reported that Atoh1 gene transfer induces the production of ectopic hair cell‑like cells (EHCLCs). In the present study, the effect of different Atoh1 expression levels and the duration of EHCLC formation on the lesser epithelial ridge (LER) of cochleae was examined using a human adenovirus serotype 5 (Ad5) vector encoding atoh1 and the reporter gene EGFP. Different Ad5‑EGFP‑atoh1/Ad5‑EGFP virus titers were added to cultured cochlear explants and EHCLCs were detected in the LER at various time points. The results demonstrated that GFP alone did not induce EHCLCs. By contrast, Atoh1 expression induced EHCLCs as early as 2.5‑5 days following EGFP‑atoh1 infection in the LER and depending upon the viral titer, the number of EHCLCs increased with time. Higher Ad5‑EGFP‑atoh1 titers induced enhanced Atoh1 expression, resulting in an increase in EHCLCs. Lower Ad5‑EGFP‑atoh1 titers required more time for EHCLC formation and very low titers of Ad5‑EGFP‑atoh1 induced only weak Atoh1 expression and did not trigger EHCLC formation. In conclusion, the present study utilized an appropriate Ad5‑EGFP‑atoh1 titer range to induce Atoh1 expression and the subsequent production of EHCLCs. The results revealed that the Atoh1 expression level defined the fate of LER cells as either EHCLCs or nonsensory epithelial cells. This evidence may provide an important guideline for future studies into gene therapy strategies for the treatment of deafness.
Department of Otolaryngology‑Head and Neck Surgery, Eye and ENT Hospital of Fudan University, Xuhui, Shanghai 200031, P.R. China.
Wen-Wei
WW
Luo
Department of Otolaryngology‑Head and Neck Surgery, Eye and ENT Hospital of Fudan University, Xuhui, Shanghai 200031, P.R. China.
Juan-Mei
JM
Yang
Department of Otolaryngology‑Head and Neck Surgery, Eye and ENT Hospital of Fudan University, Xuhui, Shanghai 200031, P.R. China.
Zhao
Z
Han
Department of Otolaryngology‑Head and Neck Surgery, Eye and ENT Hospital of Fudan University, Xuhui, Shanghai 200031, P.R. China.
Ya-Sheng
YS
Yuan
Department of Otolaryngology‑Head and Neck Surgery, Eye and ENT Hospital of Fudan University, Xuhui, Shanghai 200031, P.R. China.
Hai-Bin
HB
Sheng
Department of Otolaryngology‑Head and Neck Surgery, Eye and ENT Hospital of Fudan University, Xuhui, Shanghai 200031, P.R. China.
Xiang
X
Liu
Department of Otolaryngology‑Head and Neck Surgery, Eye and ENT Hospital of Fudan University, Xuhui, Shanghai 200031, P.R. China.
Fang-Lu
FL
Chi
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D003051:Cochlea / Q000166:cytology*; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism*; D017930:Genes, Reporter; D005822:Genetic Vectors / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics
D051792:Basic Helix-Loop-Helix Proteins; D049452:Green Fluorescent Proteins; D011993:Recombinant Fusion Proteins; C000594380:Atoh1 protein, rat; C485184:enhanced green fluorescent protein