Characterization of an induced pluripotent stem cell line (UMi040-A) bearing an auditory neuropathy spectrum disorder-associated variant in TMEM43.

Hearing loss is one of the most common sensory disorders. TMEM43 is expressed in cochlear glia-like supporting cells (GLSs) and is known to be associated with late-onset auditory neuropathy spectrum disorder (ANSD) and progressive hearing loss. Here, we describe the derivation of an induced pluripotent stem cell (iPSC) line from a patient lymphoblastoid cell line (LCL) carrying a single heterozygous nonsense variant (p.Arg372Ter (c.1114C > T)) in TMEM43 that leads to a truncated protein lacking the 4th transmembrane domain. This cell line can serve as a tool for disease modelling and development of therapeutic approaches to restore inner ear function.

Generation of hiPSC line UMi030-A from an individual with the hearing loss-related GJB2 mutation c.109G > A.

Genetic variants in the GJB2 gene which encodes for the Connexin 26 protein account for âˆ¼ 60% of cases of genetic hearing loss. A novel hiPSC line was generated from an individual with the hearing loss-related variant c.109G > A in GJB2 leading to the p.V37I alteration in the Connexin26 protein. These cells will help to delineate the role of GJB2 in hearing loss pathogenesis and serve as a platform for drug discovery and development.

Characterization of UMi031-A-2 inducible pluripotent stem cell line with a neurofibromatosis type 2-associated mutation.

The UMi031-A-2 hiPSC line contains a CRISPR-induced homozygous, Neurofibromatosis Type 2 (NF2) mutation (L64P (CTG > CCG)) in the NF2 gene that encodes a merlin tumor suppressor. This line was generated from an unaffected iPSC line using CRISPR technology and characterized for pluripotency and karyotypic stability. The c.191 T > C variant in NF2 is associated with a syndromic nervous system tumor disorder leading to the development of bilateral vestibular schwannomas. Once differentiated into Schwann cells, UMi031-A-2 can serve as a resource for the analysis of signaling pathways deregulated upon merlin defects and provide a pre-clinical platform for testing therapies for NF2 schwannomas.

Derivation of iPSC line UMi029-A bearing a hearing-loss associated variant in the SMPX gene.

Hereditary hearing loss (HL) is the most common sensory disorder with multiple potential modes of inheritance, such as X-linked. Multiple loci have been associated with X-linked HL, including variants in the Small Muscle Protein X-Linked (SMPX) gene responsible for deafness, X-linked 4 (DFNX4) (OMIM 300066). Here we describe the derivation of an induced pluripotent stem cell (iPSC) line from an individual bearing a novel splice variant (c.133-1 G > A) that leads to a frameshift creating a premature stop codon (p.(Gly45Val*36)) in SMPX[1].

Characterization of UMi028-A-1 stem cell line that contains a CRISPR/Cas9 induced hearing loss-associated variant (V60L (c.178G > T)) in the P2RX2 gene.

UMi028-A-1 hiPSC line contains a CRISPR/Cas9-induced heterozygous, hearing loss-associated variant (V60L (GTA > TTA)) in the Purinergic Receptor P2X2 (P2RX2) gene. This line, derived from an unaffected male iPSC line, has been successfully characterized for its cellular and genetic properties. The c.178G > T variant in P2RX2 is associated with non-syndromic, dominant, progressive hearing loss. Once differentiated into inner ear cell types, UMi028-A-1 will serve as a resource for understanding the molecular mechanisms underlying hearing loss and serve as a potential platform for testing therapeutic approaches to restore inner ear function.

Long-range cis-regulatory elements controlling GDF6 expression are essential for ear development.

Molecular mechanisms governing the development of the mammalian cochlea, the hearing organ, remain largely unknown. Through genome sequencing in 3 subjects from 2 families with nonsyndromic cochlear aplasia, we identified homozygous 221-kb and 338-kb deletions in a noncoding region on chromosome 8 with an approximately 200-kb overlapping section. Genomic location of the overlapping deleted region started from approximately 350 kb downstream of GDF6, which codes for growth and differentiation factor 6. Otic lineage cells differentiated from induced pluripotent stem cells derived from an affected individual showed reduced expression of GDF6 compared with control cells. Knockout of Gdf6 in a mouse model resulted in cochlear aplasia, closely resembling the human phenotype. We conclude that GDF6 plays a necessary role in early cochlear development controlled by cis-regulatory elements located within an approximately 500-kb region of the genome in humans and that its disruption leads to deafness due to cochlear aplasia.