Genetic factors are an important cause of idiopathic sensorineural hearing impairment (SNHI). From the epidemiological perspective, mutations of three deafness genes: GJB2, SLC26A4, and MT-RNR1, are much more prevalent than those of other genes worldwide. However, mutation spectra of common deafness genes differ remarkably across different populations. Here, we performed comprehensive genetic examination and haplotype analyses in 188 unrelated Mongolian families with idiopathic SNHI, and compared their mutation spectra and haplotypes to those of other European and Asian cohorts. We confirmed genetic diagnoses in 18 (9.6%) of the 188 families, including 13 with bi-allelic GJB2 mutations, three with bi-allelic SLC26A4 mutations, and two with homoplasmic MT-RNR1 m.1555A>G mutation. Moreover, mono-allelic mutations were identified in 17 families (9.0%), including 14 with mono-allelic GJB2 mutations and three with mono-allelic SLC26A4 mutations. Interestingly, three GJB2 mutations prevalent in other populations, including c.35delG in Caucasians, c.235delC in East Asians, and c.-23+1G>A in Southwest and South Asians, were simultaneously detected in Mongolian patients. Haplotype analyses further confirmed founder effects for each of the three mutations, indicating that each mutation derived from its ancestral origin independently. By demonstrating the unique spectra of deafness-associated mutations, our findings may have important clinical and scientific implications for refining the molecular diagnostics of SNHI in Mongolian patients, and for elucidating the genetic relationships among Eurasian populations.

Applying tissue engineering principles to design an auto-secretory device is a potential solution for patients suffering loss of salivary gland function. However, the largest challenge in implementing this solution is the primary culture of human salivary gland cells, because the cells are highly differentiated and difficult to expand in vitro. This situation leads to the lack of reports on the in vitro cell biology and physiology of human salivary gland cells. This study used a low-calcium culture system to selectively cultivate human parotid gland acinar (PGAC) cells from tissues with high purity in cell composition. This condition enables PGAC cells to continuously proliferate and retain the phenotypes of epithelial acinar cells to express secreting products (α-amylase) and function-related proteins (aquaporin-3, aquaporin-5, and ZO-1). Notably, when the cells reached confluence, three-dimensional (3D) cell aggregates were observed in crowded regions. These self-formed cell spheres were termed post-confluence structures (PCSs). Unexpectedly, despite being cultured in the same media, cells in PCSs exhibited higher expression levels and different expression patterns of function-related proteins compared to the two-dimensional (2D) cells. Translocation of aquoporin-3 from cytosolic to alongside the cell boundaries, and of ZO-1 molecules to the boundary of the PCSs were also observed. These observations suggest that when PGAC cells cultured on the 2D substrate would form PCSs without the help of 3D scaffolds and retain certain differentiation and polarity. This phenomenon implies that it is possible to introduce 2D substrates instead of 3D scaffolds into artificial salivary gland tissue engineering.

A small amount collagen mixed with chitosan substrate may improve the biocompatibility and promote the mucociliary differentiation in NECs. It appears that chitosan-collagen membrane is a promising scaffold for culture of the nasal epithelium, which sets the stage for studying tissue regeneration in the respiratory system.

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