Learning Objectives: To explore the phenotype of mice segregating the highly prevalent human GJB2 p.V37I variant and their differently expressed genes.
Materials and Methods: Mice from the same brood separately were divided into p.V37I Knock-in group with poorer hearing (KI, n = 10) and wild-type group (WT, n = 10). ABR was practiced every four weeks from 6-week-old to 50-week-old. Cochlears were dissected separately from 50-week-old mice for confocal immunofluorescence to count the number of hair cell. Another six 5-day-old mice also from same brood of each group were killed for cochlear. The RNA of harvested tissues were extracted and examined for analysis of Illumina MouseWG-6 v2 Expression Beadchip to compare the expression patterns by groups. Q-PCR were prepared for validation for results of the Mice Beadchip.
Results: KI group revealed progressive hearing loss from 30-week-old compared with WT group (P = 0.002), especially on frequencies of 4k, 24k and 32kHz. After dyeing by confocal immunofluorescence, it was found that 3 of 100 hair cells of middle and apical turn were missing under each field of microscope in KI group. The beadchip identified 929 up-regulated and 897 down-regulated expressed genes compared KI with WT group. Genes expressed in the cochlear from the ten most differently bi-regulated candidate genes were chosen for further q-PCR validation. As a result, Fcer1g, Nnmt, Lars2 (up-regulated) and Cuedc1 (down-regulated) genes were proved to be differentially expressed between KI and WT group.
Conlusion: GJB2 p.V37I KI mice presented progressive late-onset hearing loss with depletion in numbers of hair cell. Fcer1g, Nnmt, Lars2 and Cuedc1 genes were proved to be differentially expressed between KI and WT group.
