Chondrocyte-specific Smad4 gene conditional knockout results in hearing loss and inner ear malformation in mice

Shi Ming Yang, Zhao Hui Hou, Guan Yang, Ji Shuai Zhang, Yin Yan Hu, Jian He Sun, Wei Wei Guo, David Z.Z. He, Dong Yi Han, Wie Yen Young, Xiao Yang

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


Smad4 is the central intracellular mediator of transforming growth factor-β (TGF-β) signaling, which plays crucial roles in tissue regeneration, cell differentiation, embryonic development, and regulation of the immune system. Conventional Smad4 gene knockout results in embryonic lethality, precluding its use in studies of the role of Smad4 in inner ear development. We used chondrocyte-specific Smad4 knockout mice (Smad4Co/Co) to investigate the function of Smad4 in inner ear development. Smad4 Co/Co mice were characterized by a smaller cochlear volume, bone malformation, and abnormalities of the osseous spiral lamina and basilar membrane. The development of the hair cells was also abnormal, as evidenced by the disorganized stereocilia and reduced density of the neuronal processes beneath the hair cells. Auditory function tests revealed the homozygous Smad4Co/Co mice suffered from severe sensorineural hearing loss. Our results suggest that Smad4 is required for inner ear development and normal auditory function in mammals.

Original languageEnglish (US)
Pages (from-to)1897-1908
Number of pages12
JournalDevelopmental Dynamics
Issue number8
StatePublished - Aug 2008

All Science Journal Classification (ASJC) codes

  • Developmental Biology


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