Atoh1 induces auditory hair cell recovery in mice after ototoxic injury

Abstract

Objectives To evaluate the ability of the Ad28.gfap.atoh1 to promote hair cell regeneration and hearing recovery in cochlea injured with kanamycin and furosemide. Study Design In vivo model of hair cell ablation and subsequent treatment with Atoh1 Methods The hair cells of C57BL/6 mice were ablated with systemic administration of kanamycin and furosemide. The left ears were treated with Ad28.gfap.atoh1. Right ears were not treated. Pre-ablation audiograms and DPOAEs were compared to one or two month post-ablation studies. Harvested cochleae were examined for histologic evidence of hair cell regeneration and spiral ganglion cell survival. Results Delivery of Ad28.gfap.atoh1 results in development of auditory hair cells. There was no recovery of DPOAEs at one or two months post-treatment. Two months after delivery of Ad28.gfap.atoh1, the left ear exhibited a moderate recovery of hearing at 4 and 8 kHz (p<0.01). There was no significant difference at 16 or 32 kHz. One month after treatment, Myosin VII positive immunohistochemical staining can be seen in both the inner and outer hair cells of the treated ear. In the untreated ear, minimal myosin VII positive debris is seen, with no indication of normal hair cells. Two months after ablation, there is evidence of hair cell recovery on the treated side, while the untreated cochlea demonstrates a flattened epithelium. Untreated ears showed decreased spiral ganglion cell density at the basal turn compared to treated ears. Conclusions Ad28.gfap.atoh1 promotes hair cell regeneration in cochlea ablated with kanamycin and furosemide resulting in moderate hearing recovery.

In Vivo Interplay between p27Kip1, GATA3, ATOH1, and POU4F3 Converts Non-sensory Cells to Hair Cells in Adult Mice

“…Several studies (Izumikawa et al, 2008; Kelly et al, 2012; Liu et al, 2012) suggest that ATOH1 is ineffectual in converting SCs to HCs in mature or damaged ears, particularly in genetic mouse models. Other reports suggest that virally transduced ATOH1 (Izumikawa et al, 2005; Kawamoto et al, 2003; Kraft et al, 2013) can convert SCs to HCs in mature rodent cochleae. Our data suggest that responsiveness to ATOH1 varies across SC subtypes and that mature PCs and DCs specifically are unresponsive to ATOH1.…”

“…Our data suggest that responsiveness to ATOH1 varies across SC subtypes and that mature PCs and DCs specifically are unresponsive to ATOH1. As viral transduction of ATOH1 affects SCs other than PCs and DCs (Atkinson et al, 2014; Kawamoto et al, 2003; Kraft et al, 2013), the difference in target cells may explain the paradox. Importantly, the data here show that adult PCs and DCs can be made to respond to ectopic ATOH1 via additional manipulations of p27, GATA3, or hPOU4F3.…”

“…The vast majority of SNHL results from the loss of sensory hair cells (HCs), which, in mature mammalian cochleae, do not regenerate (McGill and Schuknecht, 1976; Soucek et al, 1986). Recently, research aimed at regenerating HCs has focused on ATOH1, a basic helix-loop-helix (bHLH) transcription factor that represents a therapeutic target for converting nonsensory supporting cells (SCs) into sensory HCs (Atkinson et al, 2014; Chen et al, 2013; Izumikawa et al, 2008; Izumikawa et al, 2005; Kawamoto et al, 2003; Kelly et al, 2012; Kraft et al, 2013; Kuo et al, 2015; Liu et al, 2012; Liu et al, 2014; Ouji et al, 2013; Pan et al, 2013; Parker et al, 2014; Wu et al, 2013; Yang et al, 2012; Yang et al, 2013; Zhao et al, 2011; Zheng and Gao, 2000). Indeed, clinical trials are being conducted to test whether an ATOH1 gene therapy can rehabilitate hearing in SNHL patients (Novartis-Pharmaceuticals).…”

Fgf-Signaling-Dependent Sox9a and Atoh1a Regulate Otic Neural Development in Zebrafish

“…Atoh1a and Atoh1b function in otic hair cell fate determination (Millimaki et al, 2007) and hair cell damage regeneration (Lewis et al, 2012; Kraft et al, 2013). In the developing otic region, the initial expression of atoh1a is genetically downstream of Atoh1b and the maintenance of atoh1b expression requires Atoh1a (Millimaki et al, 2007).…”

Hearing, reactive metabolite formation, and oxidative stress in cochleae after a single acute overdose of acetaminophen: anin vivostudy

“…These animals received 1,000 mg/kg kanamycin followed by 400 mg/kg FS 0.5 h later. This treatment has previously been shown to cause ototoxicity (Kraft et al, 2013). Furthermore, there is evidence that this is a clinically relevant model, as there are reports of hearing loss after combined treatment with aminoglycoside antibiotics and furosemide (Bates et al, 2002).…”