Novel non-synonymous mutations of PAX8 in a cohort of Chinese with congenital hypothyroidism.

BACKGROUND: The transcription factor paired box 8 (PAX8) was associated with type 2 congenital non-goitrous hypothyroidism (CHNG2), a clinical phenotype of congenital hypothyroidism (CH). Though studied in a few regions with different ethnicities, the incidence of PAX8 mutations varied, even among Chinese cohorts in different regions. This study aimed to identify and characterize PAX8 mutations and explore the prevalence of its mutations in another cohort of CH. METHODS: The 105 unrelated Chinese patients with CH were collected from four major hospitals. Exomes of the 105 samples were sequenced by Hiseq 2000 platform to identify mutations of PAX8 on genomic DNAs extracted from peripheral blood samples. Luciferase reporter assays were used to assess the effects of mutations on the transcription of thyroid peroxidase (TPO). RESULTS: Three PAX8 mutations in four subjects were identified in 105 samples. One variant, rs189229644, was detected in two subjects, and categorized as uncertain significance. The other two missense mutations (275T>C/Ile92Thr and 398G>A/Arg133Gln) were not detected in three large-scale genotyping projects, namely 1000 Genome Project, Exome Aggregation Consortium and GO Exome Sequencing Project. Functional studies for the two mutations revealed that they could impair the transcription ability of PAX8 on one of its target genes, TPO. Therefore, the two mutations were causative for the pathogenesis of CHNG2. After combining the studies of PAX8 mutations, an average frequency of 1.74% (21/1209) could be obtained in Chinese patients with CH. CONCLUSION: The study specifically demonstrates the role of two mutations in impairing the transcription ability of PAX8, which should be considered as pathogenic variants for CH.

The Short Isoform of Nuclear Mitotic Apparatus Protein 1 Functions as a Putative Tumor Suppressor.

BACKGROUND: Nuclear mitotic apparatus protein 1 (NuMA1) had been reported to produce three groups of isoforms categorized as long, middle, and short groups, of which short NuMA displayed distinct localization patterns compared to long and middle isoforms. However, the function of short NuMA was not clear in the progress of cancer formation. This study aimed to unveil the role of short NuMA in cancer pathogenesis. METHODS: The expression levels of short isoforms were explored in paired gastric carcinoma (GC) samples and different cell lines. Furthermore, the short isoform behaved as a putative tumor suppressor based on cell proliferation and cell colony formation assays. Pull-down assay and whole-genome gene expression analysis were carried out to search candidate interaction partners of short NuMA. RESULTS: The expression of short NuMA was highly expressed in S and G2 phases of the cell cycle; compared with nontumor tissues, short NuMA downregulated in nine GCs (GC1 [0.131, P = 5 × 10-4]; GC2 [0.316, P = 3 × 10-5]; GC3 [0.111, P = 6 × 10-4]; GC4 [0.456, P = 0.011]; GC5 [0.474, P = 0.001]; GC6 [0.311, P = 0.004]; GC7 [0.28, P = 3 × 10-5]; GC8 [0.298, P = 0.007]; and GC9 [0.344, P = 0.002]). Besides, high expression of short NuMA significantly inhibits cell growth (2.43 × 105 vs. 2.97 × 105, P = 0.0029) and cell clone information in vitro (70 vs. 2, P = 1.67 × 10-45). Short NuMA could bind with alpha-actinin-4 (ACTN4), a putative tumor promoting gene. Overexpression of short NuMA could tremendously decrease the expression of MYB proto-oncogene like 2 (MYBL2) of about 92-fold, which played an important role in the cell cycles. CONCLUSIONS: Short isoform of NuMA might be functioned as a putative role of tumor suppressor. Further studies should be made to illuminate the relationship between ACTN4, MYBL2, and tumor progression.

Variants in the Promoter Region of HLA-DQA1 were Associated with Idiopathic Membranous Nephropathy in a Chinese Han Population.

BACKGROUND: Idiopathic membranous nephropathy (IMN) is an autoimmune disease and the leading cause of adult nephritic syndrome. HLA-DQA1 had been identified to be associated with IMN in Europeans and the result was replicated in Chinese Han population. In this study, six single nucleotide polymorphisms (SNPs) in the promoter of HLA-DQA1 and other two SNPs with IgA nephropathy were included for the association analysis. METHODS: The SNPs were genotyped in 509 patients and 601 controls by the MassArray iPLEX. The quantification of anti-phospholipase A2 receptor (PLA2R) antibodies in sera of IMN patients was performed by anti-PLA2R ELISA (IgG) kit. RESULTS: After analysis, four SNPs were significantly associated with IMN, with rs2187668 and rs28383345 as the top two signals (P = 8.42×10-5 and 2.48×10-5, respectively). Even under dominant model, the two SNPs were still significantly associated with IMN (P = 3.50×10-3 for rs28383345 and P = 6.55×10-5 for rs2187668). After conditional study with rs2187668, rs28383345 was the only variant significantly correlated with IMN after Bonferroni correction (P = 0.016). The minor alleles of the two SNPs were also mutually exclusive in our cohort. This indicated that the two SNPs were independently associated with IMN in Chinese Han population. Levels of anti-PLA2R autoantibodies were correlated with the genotypes of the two SNPs, but not significantly (P>0.05). CONCLUSIONS: Our results revealed that a novel independent variant in the promoter of HLA-DQA1 was associated with IMN in Chinese Han population. The locus possessed regulatory role according to the data of RegulomeDB. The exact role of the SNPs on the expression of HLA-DQA1 needs further investigation.