Guided genetic screen to identify genes essential in the regeneration of hair cells and other tissues

TLDR

Regenerative medicine offers promise for degenerative diseases and traumatic injury, yet mammals cannot regenerate inner ear hair cells—a loss that causes hearing impairment—whereas non‑mammalian vertebrates can fully restore these mechanosensory receptors. The study aimed to elucidate the mechanisms of hair cell regeneration and its link to regeneration of other tissues by conducting a guided mutagenesis screen in zebrafish lateral line hair cells. Researchers generated mutations via retroviral insertion or CRISPR/Cas9 and implemented a high‑throughput pipeline to assess hair cell development and regeneration. Screening 254 gene mutations revealed seven genes essential for hair cell regeneration that belong to distinct functional categories and also influence caudal fin and liver regeneration, demonstrating that guided screening identifies regeneration candidates and that hair cell regeneration is associated with other tissue regeneration.

Abstract

Regenerative medicine holds great promise for both degenerative diseases and traumatic tissue injury which represent significant challenges to the health care system. Hearing loss, which affects hundreds of millions of people worldwide, is caused primarily by a permanent loss of the mechanosensory receptors of the inner ear known as hair cells. This failure to regenerate hair cells after loss is limited to mammals, while all other non-mammalian vertebrates tested were able to completely regenerate these mechanosensory receptors after injury. To understand the mechanism of hair cell regeneration and its association with regeneration of other tissues, we performed a guided mutagenesis screen using zebrafish lateral line hair cells as a screening platform to identify genes that are essential for hair cell regeneration, and further investigated how genes essential for hair cell regeneration were involved in the regeneration of other tissues. We created genetic mutations either by retroviral insertion or CRISPR/Cas9 approaches, and developed a high-throughput screening pipeline for analyzing hair cell development and regeneration. We screened 254 gene mutations and identified 7 genes specifically affecting hair cell regeneration. These hair cell regeneration genes fell into distinct and somewhat surprising functional categories. By examining the regeneration of caudal fin and liver, we found these hair cell regeneration genes often also affected other types of tissue regeneration. Therefore, our results demonstrate guided screening is an effective approach to discover regeneration candidates, and hair cell regeneration is associated with other tissue regeneration.