Coexistence of mutations in keratin 10 (KRT10) and the mitochondrial genome in a patient with ichthyosis with confetti and Leber's hereditary optic neuropathy

Use of dual genomic sequencing to screen mitochondrial diseases in pediatrics: a retrospective analysis

Mitochondrial diseases (MDs) were a large group multisystem disorders, attributable in part to the dual genomic control. The advent of massively sequencing has improved diagnostic rates and speed, and was increasingly being used as a first-line diagnostic test. Paediatric patients (aged < 18 years) who underwent dual genomic sequencing were enrolled in this retrospective multicentre study. We evaluated the mitochondrial disease criteria (MDC) and molecular diagnostic yield of dual genomic sequencing. Causative variants were identified in 177 out of 503 (35.2%) patients using dual genomic sequencing. Forty-six patients (9.1%) had mitochondria-related variants, including 25 patients with nuclear DNA (nDNA) variants, 15 with mitochondrial DNA (mtDNA) variants, and six with dual genomic variants (MT-ND6 and POLG; MT-ND5 and RARS2; MT-TL1 and NARS2; MT-CO2 and NDUFS1; MT-CYB and SMARCA2; and CHRNA4 and MT-CO3). Based on the MDC, 15.2% of the patients with mitochondria-related variants were classified as "unlikely to have mitochondrial disorder". Moreover, 4.5% of the patients with non-mitochondria-related variants and 1.43% with negative genetic tests, were classified as "probably having mitochondrial disorder". Dual genomic sequencing in suspected MDs provided a more comprehensive and accurate diagnosis for pediatric patients, especially for patients with dual genomic variants.

Transcript levels of keratin 1/5/6/14/15/16/17 as potential prognostic indicators in melanoma patients

Keratins (KRTs), the intermediate filament-forming proteins of epithelial cells, are extensively used as diagnostic biomarkers in cancers and associated with tumorigenesis and metastasis in multiple cancers. However, the diverse expression patterns and prognostic values of KRTs in melanoma have yet to be elucidated. In the current study, we examined the transcriptional and clinical data of KRTs in patients with melanoma from GEO, TCGA, ONCOMINE, GEPIA, cBioPortal, TIMER and TISIDB databases. We found that the mRNA levels of KRT1/2/5/6/8/10/14/15/16/17 were significantly differential expressed between primary melanoma and metastatic melanoma. The expression levels of KRT1/2/5/6/10/14/15/16/17 were correlated with advanced tumor stage. Survival analysis revealed that the high transcription levels of KRT1/5/6/14/15/16/17 were associated with low overall survival in melanoma patients. GSEA analysis indicated that the most involved hallmarks pathways were P53 pathway, KRAS signaling, estrogen response early and estrogen response late. Furthermore, we found some correlations among the expression of KRTs and the infiltration of immune cells. Our study may provide novel insights for the selection of prognostic biomarkers for melanoma.

TMT-labeling Proteomics of Papillary Thyroid Carcinoma Reveal Invasive Biomarkers

Background and Aim: Invasion and metastasis are critical events in papillary thyroid carcinoma (PTC) progression. Protein markers specific to this process may avoid over-treatment and urgently needed.

Methods: TMT-labeled mass spectrometry-based proteomics were carried out on PTC and invasive phenotype (iPTC) (3 pairs per group) and cross validate differentially expressed proteins (DEPs) (FC>1.5 and <0.67 and p<0.05) with GEO and TCGA datasets and the correlation genes of DEPs were also analyzed.

Results: We identified and quantified 4607 proteins identical to PTC and iPTC groups. Among which 12 DEPs in PTC and 179 DEPs in iPTCs were found. Cross-validation with GSE60542 and TCGA database revealed 10 DEPs that all significant correlated with metastasis and staging. Upregulated SLC27A6 showed negative correlation with 6 out of 9 downregulated DEPs including HGD, CA4, COL23A1, SLC26A7, FHL1 and TPO.

Conclusion: The panel of 7 genes (SLC27A6 and 6 downregulated DEPs) could have ideal prediction value to improve our understanding of invasiveness of PTC.

Ichthyosis with confetti caused by new and recurrent mutations in KRT10 associated with varying degrees of keratin 10 mis-localization

BACKGROUND

Ichthyosis with confetti (IWC) is an extremely rare autosomal-dominant genodermatosis characterized by erythroderma with numerous confetti-like pale spots. IWC is caused by mutations in KRT10 (IWC-I) or KRT1 (IWC-II) which affect their tail domains. In IWC-I, the mutations lead to replacement of glycine/serine-rich keratin 10 (K10) tail with arginine- or alanine-rich frameshift motifs, causing K10 mis-localization which might trigger loss of the mutant KRT10 allele via mitotic recombination, leading to genetic reversion.

OBJECTIVE

To investigate mutations in five IWC-I patients and their functional consequences.

METHODS

We performed Sanger sequencing of KRT1 and KRT10 in peripheral blood samples of five patients, with highly polymorphic KRT10 SNPs genotyped to confirm loss-of-heterozygosity in the epidermis of pale spots. K10 expression pattern was examined in both patient skin biopsies and HaCaT cells overexpressing mutant KRT10-enhanced green fluorescence protein fusion.

RESULTS

Four novel and one recurrent KRT10 mutations were identified in patient peripheral blood samples but not in the corresponding pale spot epidermis. Two of the mutations, c.1696_1699dupCACA and c.1676dupG, affected residues close to K10 carboxyl terminus and encoded only 3 and 6 arginine residues, which were far fewer than reported previously. Interestingly, imaging analyses for K10 in HaCaT cells overexpressing either of these two mutations and in the corresponding patients' affected skin, showed a remarkably lower level of K10 mis-localization compared to that of other mutations reported in this study.

CONCLUSIONS

Our findings suggest that the number of arginine residues in the mutant tail may correlate with the level of K10 mis-localization in IWC-I keratinocytes. These results expand the genotypic and phenotypic spectrum of IWC-I.

Arginine- but not alanine-rich carboxy-termini trigger nuclear translocation of mutant keratin 10 in ichthyosis with confetti

Ichthyosis with confetti (IWC) is a genodermatosis associated with dominant-negative variants in keratin 10 (KRT10) or keratin 1 (KRT1). These frameshift variants result in extended aberrant proteins, localized to the nucleus rather than the cytoplasm. This mislocalization is thought to occur as a result of the altered carboxy (C)-terminus, from poly-glycine to either a poly-arginine or -alanine tail. Previous studies on the type of C-terminus and subcellular localization of the respective mutant protein are divergent. In order to fully elucidate the pathomechanism of IWC, a greater understanding is critical. This study aimed to establish the consequences for localization and intermediate filament formation of altered keratin 10 (K10) C-termini. To achieve this, plasmids expressing distinct KRT10 variants were generated. Sequences encoded all possible reading frames of the K10 C-terminus as well as a nonsense variant. A keratinocyte line was transfected with these plasmids. Additionally, gene editing was utilized to introduce frameshift variants in exon 6 and exon 7 at the endogenous KRT10 locus. Cellular localization of aberrant K10 was observed via immunofluorescence using various antibodies. In each setting, immunofluorescence analysis demonstrated aberrant nuclear localization of K10 featuring an arginine-rich C-terminus. However, this was not observed with K10 featuring an alanine-rich C-terminus. Instead, the protein displayed cytoplasmic localization, consistent with wild-type and truncated forms of K10. This study demonstrates that, of the various 3' frameshift variants of KRT10, exclusively arginine-rich C-termini lead to nuclear localization of K10.