Genetic testing and prenatal diagnosis for a Chinese pedigree affected with Waardenburg syndrome type 4C due to heterozygous deletion of SOX10 gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a Chinese pedigree featuring congenital profound syndromic deafness and chronic constipation, and provide prenatal diagnosis for a high-risk fetus.@*METHODS@#Whole-exome sequencing was carried out to analyze the sequences of genes associated with hereditary deafness, and multiplex ligation-dependent probe amplification (MLPA) was used to verify the candidate variant in the proband's parents and the fetus.@*RESULTS@#The proband was found to have harbored a heterozygous deletion of SOX10, a pathogenic gene associated with Waardenburg syndrome type 4C (WS4C). The same deletion was found in her mother (with profound syndromic deafness and chronic constipation) and the fetus, but not in her father with normal hearing. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG) and Association for Molecular Pathology (AMP), the SOX10 gene deletion was predicted to be a pathogenic variant (PVS1+PM2_Supporting+PP1+PP4).@*CONCLUSION@#The pedigree was diagnosed with WS4C, which has conformed to an autosomal dominant inheritance. Deletion of the entire SOX10 gene, as a loss-of-function variant, probably underlay its pathogenesis. Above finding has facilitated genetic counseling and prenatal diagnosis for this family.

Analysis of genetic characteristics in two Chinese children of type Ⅱ Waardenburg syndrome / 中华耳鼻咽喉头颈外科杂志

Objective: To screen and analyze the mutations of MITF gene in two children of type Ⅱ Waardenburg syndrome (WS2) from different families in Yunnan,China,and to explore the possible molecular pathogenesis. Methods: With informed consent, medical history collection, physical examinations, audiological evaluation, and high resolution computer tomography (HRCT) scan of temporal bone were performed on the two WS2 probands and their family members. Genomic DNA was extracted from peripheral blood of all individuals. The coding regions including all exons, part of introns and promoters of MITF, PAX3, SOX10, SNAI2, END3, ENDRB, and KITLG genes were sequenced by high-throughput sequencing. According to the results of high-throughput sequencing, pathogenic mutations detected in the probands and their parents were verified by Sanger sequencing. Results: The proband 1 carried c.641_643delGAA mutation in the 7th exon of MITF gene, which was a frame-shift mutation resulting in an amino acid change of p.214delR. It was a de novo mutation as the parents of proband 1 showed no variation on this site. The proband 2 carried heterozygous loss of the large fragment ranging from exon 1 to exon 9 of MITF gene, which defected the function of MITF protein. Conclusion: Genetic examinations provide important evidence for diagnosis of Waardenburg syndrome. Heterozygous mutation c.641_643delGAA and heterozygous loss of the large fragment ranging from exon 1 to exon 9 of MITF gene might be the molecular pathogenesis of the two WS2 probands in this study.

Effect of electroacupuncture at "Jiaji" (EX-B 2) points on the proliferation and differentiation of oligodendrocyte precursor cells in rats with acute spinal cord injury / 中国针灸

OBJECTIVE@#To observe the effect of electroacupuncture (EA) at "Jiaji" (EX-B 2) points on the proliferation and differentiation of oligodendrocyte precursor cells in rats with acute incomplete spinal cord injury, and to explore the mechanism of EA on improving motor function of spinal cord injury.@*METHODS@#A total of 72 male SPF SD rats were randomly divided into a sham operation group, a model group, an EA group and a medication group, 18 rats in each group. Each group was further divided into 1-day subgroup, 7-day subgroup and 14-day subgroup, 6 rats in each subgroup. The T acute incomplete spinal cord injury model was established by modified Allen's method in the model group, EA group and medication group. The rats in each group received intraperitoneal injection of 5-bromodeoxyuridine (BrdU, 50 mg/kg), once a day, and each subgroup received continuous injection for 1, 7, 14 times for cell proliferation labeling. The rats in the EA group were treated with EA at "Jiaji" (EX-B 2) points 3-4 mm next the spinous process of the upper and lower segments of the injured spinal cord (T, T) with a frequency of 2 Hz/100 Hz and intensity of 1-2 mA. The muscle twitch at the treatment site was taken as the degree. The treatment was given 20 min each time, once a day. In the medication group, monosialogangliosides (GM1) was injected intraperitoneally (10 mg/kg), once a day. The subgroups of EA group and medication group were treated for 1, 7, 14 times. The score of Basso Beattie Bresnahan (BBB) was used to evaluate the motor function of hind limbs. The co-expression of BrdU/NG2 positive cells was detected by immunofluorescence, and the expression of Olig2 and Sox10 was detected by Western blot.@*RESULTS@#Compared with the sham operation group, the BBB score was decreased 1 day, 7 days and 14 days after operation in the model group (<0.05), the expression of Olig2 and Sox10 was increased (<0.05), and the co-expression of BrdU/NG2 positive cells was increased 7 days and 14 days after operation (<0.05). Seven days and 14 days after operation, the BBB score in the EA group and medication group was higher than that in the model group (<0.05), and the co-expression of BrdU/NG2 in the medication group was higher than that in the model group (<0.05). Fourteen days after operation, the co-expression of BrdU/NG2 in the EA group was higher than that in the model group (<0.05); 1 day, 7 days and 14 days after operation, the expression of Olig2 and Sox10 in the EA group and medication group was higher than that in the model group (<0.05). Compared with the medication group, the co-expression of BrdU/NG2 positive cells in the EA group 14 days after operation was decreased (<0.05); 1 day, 7 days and 14 days after operation, the expression of Olig2 and Sox10 in the EA group was decreased (<0.05).@*CONCLUSION@#EA at "Jiaji" (EX-B 2) points could promote the expression of Olig2 and Sox10 after spinal cord injury, which has similar effects with GM1. It could promote the proliferation and differentiation of oligodendrocyte precursor cells into oligodendrocytes, so as to promote the recovery of motor function of rats.

Prenatal diagnosis of a novel SOX10 mutation in a patient with syndromic hearing loss / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a patient with syndromic hearing loss.@*METHODS@#Genomic DNA of the patient was extracted, for which 127 deafness-related genes were enriched with a chip. Following next generation sequencing, pathogenic loci in exonic regions were analyzed through comparison against the databases. Genotype of her fetus for the suspected site was determined by testing the amniotic fluid sample. qPCR method was applied to verify the deletion of a large fragment.@*RESULTS@#The proband was diagnosed with Waardenburg syndrome type 2, and had harbored a novel heterozygous deletion of the exons 3 and 4 of the SOX10 gene. Her fetus was found to carry the same deletion and presented with blue eyes and deafness after birth.@*CONCLUSION@#Waardenburg syndrome type 2 due to SOX10 gene deletion may feature autosomal dominant inheritance with incomplete penetrance. The deletion of exons 3 and 4 of the SOX10 gene probably underlies the disease in this family.

Influence of SOX10 on the proliferation and invasion of prostate cancer cells / 北京大学学报(医学版)

OBJECTIVE@#To explore the influence of SOX10 on the proliferation and invasion of prostate cancer cells.@*METHODS@#SOX10 protein in prostate cancer cell lines PC3, DU145 and LNcap was detected by Western blotting analysis. The expression of SOX10 in prostate cancer cell lines (PC3 and DU145) were knocked down by small interfering RNAs, and the efficiency of SOX10 by small interfering RNAs was confirmed using Western blotting analysis. CCK-8 assays were conducted to assess the influences of SOX10 on the proliferation of PC3 and DU145 cells, and invasion assays were conducted to assess the influences of SOX10 on the invasion of PC3 and DU145 cells.@*RESULTS@#After SOX10 in prostate cancer cells was knocked down by small interfering RNAs, the proliferation of prostate cancer cells PC3 and DU145 was significantly inhibited. Results of CCK-8 assays showed that the absorbance of PC3 and DU145 in SOX10-silenced groups was decreased compared with those in control groups (PC3: 0 d: 0.166±0.01, 0.162±0.012 vs. 0.155 ±0.01, P>0.05; 1 d: 0.210±0.011, 0.211±0.018 vs. 0.252±0.023, P>0.05; 2 d: 0.293±0.017, 0.280±0.028 vs. 0.433±0.030, P<0.01; 3 d: 0.363±0.071, 0.411±0.038 vs. 0.754±0.045, P<0.01; 4 d: 0.592±0.065, 0.670±0.093 vs. 1.456±0.111, P<0.01. DU145: 0 d: 0.168±0.018, 0.164±0.01 vs. 0.153 ±0.012, P>0.05; 1 d: 0.218±0.007, 0.206±0.024 vs. 0.255±0.02, P>0.05; 2 d: 0.297±0.013, 0.291±0.012 vs. 0.444±0.023, P<0.05; 3 d: 0.378±0.058, 0.419±0.026 vs. 0.762±0.039, P<0.01; 4 d: 0.681±0.094, 0.618±0.050 vs. 1.419±0.170, P<0.01). Meanwhile, knocking down SOX10 significantly suppressed the invasion of prostate cancer cells PC3 and DU145. Results of invasion assays showed that the numbers of invaded cells in SOX10-silenced groups were significantly less than those in control groups (PC3: 142±38, 171±17 vs. 304±55; DU145: 96±22, 134±23 vs. 341±34, P<0.05).@*CONCLUSION@#SOX10 might promote prostate cancer progression by accelerating the ability of the proliferation and invasion of prostate cancer cells, and SOX10 might be a potential therapeutic target for prostate cancer.

Kallmann syndrome with deafness caused by SOX10 mutation: Advances in research / 中华男科学杂志

The transcription factor SOX10, as a major actor in the development of the neural crest, plays a key role in the maintenance of progenitor cell multipotency, lineage specification, and cell differentiation. Abnormalities of neural crest development in humans lead to a number of genetic diseases known as neurocristopathies or neural crest disorders. The mutation of SOX10 can cause Kallmann syndrome (KS), which is a clinically and genetically heterogeneous condition and defined by the association between anosmia and hypogonadotropic hypogonadism due to incomplete migration of neuroendocrine gonadotropin-releasing hormone (GnRH) cells along the olfactory, vomeronasal, and terminal nerves. Since then, there have been a number of related reports that mutation of SOX10 will lead to KS with deafness. This review focuses on the SOX10 gene and the advances in the diagnosis and genetic studies of KS with deafness caused by the mutatuin of SOX10.

PDK2 promotes chondrogenic differentiation of mesenchymal stem cells by upregulation of Sox6 and activation of JNK/MAPK/ERK pathway

This study was undertaken to clarify the role and mechanism of pyruvate dehydrogenase kinase isoform 2 (PDK2) in chondrogenic differentiation of mesenchymal stem cells (MSCs). MSCs were isolated from femurs and tibias of Sprague-Dawley rats, weighing 300-400 g (5 females and 5 males). Overexpression and knockdown of PDK2 were transfected into MSCs and then cell viability, adhesion and migration were assessed. Additionally, the roles of aberrant PDK2 in chondrogenesis markers SRY-related high mobility group-box 6 (Sox6), type ΙΙ procollagen gene (COL2A1), cartilage oligomeric matrix protein (COMP), aggrecan (AGC1), type ΙX procollagen gene (COL9A2) and collagen type 1 alpha 1 (COL1A1) were measured by quantitative reverse-transcription polymerase chain reaction (qRT-PCR). The expressions of c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK) and extracellular regulated protein kinase (ERK) were measured. Overexpressing PDK2 promoted cell viability, adhesion and inhibited cell migration in MSCs (all P<0.05). qRT-PCR assay showed a potent increase in the mRNA expressions of all chondrogenesis markers in response to overexpressing PDK2 (P<0.01 or P<0.05). PDK2 overexpression also induced a significant accumulation in mRNA and protein expressions of JNK, p38MAPK and ERK in MSCs compared to the control (P<0.01 or P<0.05). Meanwhile, silencing PDK2 exerted the opposite effects on MSCs. This study shows a preliminary positive role and potential mechanisms of PDK2 in chondrogenic differentiation of MSCs. It lays the theoretical groundwork for uncovering the functions of PDK2 and provides a promising basis for repairing cartilage lesions in osteoarthritis.

Mutation analysis of seven patients with Waardenburg syndrome / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To perform genetic analysis for 7 patients with Waardenburg syndrome.</p><p><b>METHODS</b>Potential mutation of MITF, PAX3, SOX10 and SNAI2 genes was screened by polymerase chain reaction and direct sequencing. Functions of non-synonymous polymorphisms were predicted with PolyPhen2 software.</p><p><b>RESULTS</b>Seven mutations, including c.649-651delAGA (p.R217del), c.72delG (p.G24fs), c.185T>C (p.M62T), c.118C>T (p.Q40X), c.422T>C (p.L141P), c.640C>T (p.R214X) and c.28G>T(p.G43V), were detected in the patients. Among these, four mutations of the PAX3 gene (c.72delG, c.185T>C, c.118C>T and c.128G>T) and one SOX10 gene mutation (c.422T>C) were not reported previously. Three non-synonymous SNPs (c.185T>C, c.128G>T and c.422T>C) were predicted as harmful.</p><p><b>CONCLUSION</b>Genetic mutations have been detected in all patients with Waardenburg syndrome.</p>

Molecular pathogenesis of Waardenburg syndrome type II resulting from SOX10 gene mutation / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the molecular mechanism of Waardenburg syndrome type II (WS2) resulting from SOX10 gene mutation E248fs through in vitro experiment.</p><p><b>METHODS</b>293T cells were transiently transfected with wild type (WT) SOX10 and mutant type (MT) E248fs plasmids. The regulatory effect of WT/MT SOX10 on the transcriptional activity of MITF gene and influence of E248fs on WT SOX10 function were determined with a luciferase activity assay. The DNA binding capacity of the WT/MT SOX10 with the promoter of the MITF gene was determined with a biotinylated double-stranded oligonucleotide probe containing the SOX10 binding sequence cattgtc to precipitate MITF and E248fs, respectively. The stability of SOX10 and E248fs were also analyzed.</p><p><b>RESULTS</b>As a loss-of-function mutation, the E248fs mutant failed to transactivate the MITF promoter as compared with the WT SOX10 (P<0.01), which also showed a dominant-negative effect on WT SOX10. The WT SOX10 and E248fs mutant were also able to bind specifically to the cattgtc motif in the MITF promoter, whereas E248fs had degraded faster than WT SOX10.</p><p><b>CONCLUSION</b>Despite the fact that the E248fs has a dominant-negative effect on SOX10, its reduced stability may down-regulate the transcription of MITF and decrease the synthesis of melanin, which may result in haploinsufficiency of SOX10 protein and cause the milder WS2 phenotype.</p>

Clinical classification and genetic mutation study of two pedigrees with type II Waardenburg syndrome / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the molecular etiology of two pedigrees affected with type II Waardenburg syndrome (WS2) and to provide genetic diagnosis and counseling.</p><p><b>METHODS</b>Blood samples were collected from the proband and his family members. Following extraction of genomic DNA, the coding sequences of PAX3, MITF, SOX10 and SNAI2 genes were amplified with PCR and subjected to DNA sequencing to detect potential mutations.</p><p><b>RESULTS</b>A heterozygous deletional mutation c.649_651delAGA in exon 7 of the MITF gene has been identified in all patients from the first family, while no mutation was found in the other WS2 related genes including PAX3, MITF, SOX10 and SNAI2.</p><p><b>CONCLUSION</b>The heterozygous deletion mutation c.649_651delAGA in exon 7 of the MITF gene probably underlies the disease in the first family. It is expected that other genes may also underlie WS2.</p>

Construction and analysis of recombinant eukaryotic expression plasmids for SOX10, the causative gene of Warrdenburg syndrome / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To study the exogenous expression and subcellular localization of wild type (WT) and mutant SOX10 proteins in vitro through generation of expression plasmids in order to reveal the pathogenesis of Waardenburg syndrome (WS).</p><p><b>METHODS</b>The plasmids pECE-SOX10 and pCMV-Flag were ligated after they were subjected to double enzyme digestion using molecular cloning technique to generate recombinant eukaryotic expression plasmid pCMV-SOX10-Flag, which was as a template to generate expression plasmids for novel mutations G37fs, G38fs and E248fs of the SOX10 gene. The constructs were verified by direct sequencing. NIH3T3 cells were transiently transfected with the expression plasmids of wide type SOX10, G37fs, G38fs and E248fs, respectively. The exogenous expression of WT SOX10 protein and mutant G37fs, G38fs and E248fs proteins were analyzed using Western blot assay, while their subcellular distribution were observed with an immunofluorescence assay.</p><p><b>RESULTS</b>The DNA sequences of expression plasmids for SOX10 and its mutant G37fs, G38fs and E248f were all correct. Both WT and mutant SOX10 proteins were detected at the expected site. WT SOX10 and E248fs proteins have only localized in the nucleus, whereas G37fs and G38fs proteins showed aberrant localization in both cytoplasm and nucleus.</p><p><b>CONCLUSION</b>Recombinant eukaryotic expression plasmids for the SOX10 gene and its mutants were successfully constructed. Preliminary analysis showed that the mutations have affected the subcellular distribution of WT SOX10 proteins, which has laid a basis for further study of the molecular mechanism of WS caused by SOX10 gene mutations.</p>

Glyceollins, a novel class of soybean phytoalexins, inhibit SCF-induced melanogenesis through attenuation of SCF/c-kit downstream signaling pathways

The anti-melanogenesis effect of glyceollins was examined by melanin synthesis, tyrosinase activity assay in zebrafish embryos and in B16F10 melanoma cells. When developing zebrafish embryos were treated with glyceollins, pigmentation of the embryos, melanin synthesis and tyrosinase activity were all decreased compared with control zebrafish embryos. In situ expression of a pigment cell-specific gene, Sox10, was dramatically decreased by glyceollin treatment in the neural tubes of the trunk region of the embryos. Stem cell factor (SCF)/c-kit signaling pathways as well as expression of microphthalmia-associated transcription factor (MITF) were determined by western blot analysis. Glyceollins inhibited melanin synthesis, as well as the expression and activity of tyrosinase induced by SCF, in a dose-dependent manner in B16F10 melanoma cells. Pretreatment of B16F10 cells with glyceollins dose-dependently inhibited SCF-induced c-kit and Akt phosphorylation. Glyceollins significantly impaired the expression and activity of MITF. An additional inhibitory function of glyceollins was to effectively downregulate intracellular cyclic AMP levels stimulated by SCF in B16F10 cells. Glyceollins have a depigmentation/whitening activity in vitro and in vivo, and that this effect may be due to the inhibition of SCF-induced c-kit and tyrosinase activity through the blockade of downstream signaling pathway.