ALOX5-mediated ferroptosis acts as a distinct cell death pathway upon oxidative stress in Huntington's disease.

Although it is well established that Huntington's disease (HD) is mainly caused by polyglutamine-expanded mutant huntingtin (mHTT), the molecular mechanism of mHTT-mediated actions is not fully understood. Here, we showed that expression of the N-terminal fragment containing the expanded polyglutamine (HTTQ94) of mHTT is able to promote both the ACSL4-dependent and the ACSL4-independent ferroptosis. Surprisingly, inactivation of the ACSL4-dependent ferroptosis fails to show any effect on the life span of Huntington's disease mice. Moreover, by using RNAi-mediated screening, we identified ALOX5 as a major factor required for the ACSL4-independent ferroptosis induced by HTTQ94. Although ALOX5 is not required for the ferroptotic responses triggered by common ferroptosis inducers such as erastin, loss of ALOX5 expression abolishes HTTQ94-mediated ferroptosis upon reactive oxygen species (ROS)-induced stress. Interestingly, ALOX5 is also required for HTTQ94-mediated ferroptosis in neuronal cells upon high levels of glutamate. Mechanistically, HTTQ94 activates ALOX5-mediated ferroptosis by stabilizing FLAP, an essential cofactor of ALOX5-mediated lipoxygenase activity. Notably, inactivation of the Alox5 gene abrogates the ferroptosis activity in the striatal neurons from the HD mice; more importantly, loss of ALOX5 significantly ameliorates the pathological phenotypes and extends the life spans of these HD mice. Taken together, these results demonstrate that ALOX5 is critical for mHTT-mediated ferroptosis and suggest that ALOX5 is a potential new target for Huntington's disease.

The occurrence and distribution characteristics of Cronobacter in diverse cereal kernels, flour, and flour-based products.

Cronobacter was positive in cereals at a relatively high rate. In the present study, we investigated the occurrence and characteristics of this pathogen systematically in diverse cereals. All sampled food (N = 467) contained Cronobacter with a high positive rate of 54.0%. The enumeration experiment showed the concentration ranged from 0.3 to more than 110 MPN/100 g, and 87.9% of 127 samples were less than 10 MPN/100 g. There were significant differences (p < 0.05) in positive rates for Cronobacter among cereal kernels (40.2%), cereal flour (66.7%), cereal products made from raw cereal flour (87.6%), and cereal products made from flour (ready-to-eat) (17.4%). The dominant Cronobacter species was C. sakazakii and C. dublinensis, followed by C. malonaticus and C. turicensis. Two interesting clusters with more than 90% similarities were identified by pulsed-field gel electrophoresis (PFGE). The C1 cluster (four isolates) indicated these strains were derived from a common source and persisted in the food production environment for an extended time. The C2 cluster (six isolates) indicated the pathogen could be transmitted via cereal processing. Our research provided baseline data for Cronobacter in diverse cereals and was helpful for understanding Cronobacter transmission. The results also indicate that additional control measures should be developed to reduce the risk of infection by these opportunistic pathogenic bacteria.

Potential reservoirs and routes of Cronobacter transmission during cereal growing, processing and consumption.

Cronobacter are opportunistic bacterial pathogens of both infants and adults. We investigated the incidence and distribution of Cronobacter in 1245 samples of cereal and related environments. 39.1% (101/258) rice-related and 46.9% (98/209) wheat-related samples tested positive for Cronobacter, and the positive rate differed notably according to processing method. Cronobacter was found in rice and wheat plants at the tillering, filling and mature stages. Soil, water and swab samples from nearby milling plants were assayed, and results revealed that 6.3% (7/122) of water from paddy fields, 49.1% (28/57) and 62.1% (41/67) of swab samples from rice and wheat flour milling plants were Cronobacter positive. Pulsed-field gel electrophoresis (PFGE) subtyping indicated that some strains had a common profile, which suggested their persistence in the environment, potential transmission routes and cross-contamination in processing. Finally, we surveyed 18 families to evaluate potential risks. None of the families who primarily ate rice cooked with water tested positive for Cronobacter, though of 66.7% families (6/9) whose food staples were produced from wheat flour tested positive. Taken together, our results are important for understanding Cronobacter transmission and will aid in the development of additional control measures to reduce the risk of infection by these opportunistic pathogenic bacteria.

[Three novel splicing mutations at 5' terminal of DMD gene corresponding to different phenotypes].

OBJECTIVE: To study the correlation of splicing mutations at the 5' end of the DMD gene with their phenotypes. METHODS: DMD gene mutations were analyzed using Multiplex Ligation Probe Amplification (MLPA) and Sanger sequencing. Co-segregation analysis was performed for the pedigrees of the probands. Influence of mutations on protein function was predicted by bioinformatic analysis. RESULTS: Three novel splicing mutations were identified in three patients with different phenotypes. Patient 1 carried a c.31+3insT mutation and presented primarily with dilated cardiomyopathy (XLDC). There was no clinical signs of skeletal myopathy. Bioinformatic analysis predicted that the mutation may inactivate the splicing donor of intron 1 and lead to premature termination of protein translation. Patient 2 carried a c.264_264+4delTGTAA mutation, which led to loss of splicing donor site for intron 4, and manifested Becker muscular dystrophy (BMD). The mutation was predicted to result in skipping of exon 4. The defective protein may still retain most of its function. Patient 3 had Duchenne muscular dystrophy (DMD) and carried a c.832-3C>T mutation which was predicted to decrease the activity of splicing acceptor of intron 8, resulting in usage of alternative acceptor site or retain of intron 8. All related transcripts may cause premature termination of protein translation and complete loss of protein function. The three mutations were all inherited from the mothers of the patients. CONCLUSION: Three novel splicing mutations were discovered at the 5' end of DMD gene in three patients with different disease phenotypes. Our study may facilitate understanding of the influence of splicing mutations at the 5' end of the DMD gene on dystrophin function and the correlation between genotypes and phenotypes.

Characterization of the complete sequences and stability of plasmids carrying the genes aac(6')-Ib-cr or qnrS in Shigella flexneri in the Hangzhou area of China.

The aim of this study was to explore the fluoroquinolone resistance mechanism of aac (6')-Ib-cr and qnrS gene by comparing complete sequences and stability of the aac(6')-Ib-cr- and qnrS-positive plasmids from Shigella isolates in the Hangzhou area of China. The complete sequences of four newly acquired plasmids carrying aac(6')-Ib-cr or qnrS were compared with those of two plasmids obtained previously and two similar reference Escherichia coli plasmids. The results showed that the length, antibiotic resistance genes and genetic environment were different among the plasmids. Moreover, the plasmid stability of three wild-type isolates and five plasmid transformants carrying aac(6')-Ib-cr and/or qnrS was measured in vitro, and all eight isolates were found to have lost their aac(6')-Ib-cr- or qnrS-positive plasmids to a different extent at different stages. When the plasmids were electroporated into Shigella flexneri or they lost positive plasmids, the MICs of ciprofloxacin increased or decreased two- to eightfold for aac(6')-Ib-cr-positive plasmids and 16- to 32-fold for qnrS-positive plasmids. To our knowledge, this is the first report comparing the complete sequences and describing stability for the aac(6')-Ib-cr- and qnrS-positive plasmids from Shigella isolates.

[The clinical presentation and gene mutation of probands in Chinese patients with Charcot-Marie-Tooth disease].

OBJECTIVE: To identify the gene mutation of Chinese Charcot-Marie-Tooth (CMT) pedigrees and investigate the association of gene mutation to the clinical manifestations and electrophysiology, and the underlying mechanisms. METHODS: A total of 105 pedigrees with CMT in our hospital were enrolled from January, 2007 to December 2013. The clinical features, CMT neuropathy score (CMTNS) and electrophysiological data were collected. Gene mutations were analyzed using multiplex ligation-dependent probe amplification (MLPA) and Sanger gene sequencing. RESULTS: We found 31(29.5%) PMP22 duplication pedigrees, 8(7.6%) GJB1 mutation pedigrees, 4(3.8%) MFN2 mutation pedigrees, 4(3.8%) HSPB1 mutation pedigrees, 3(2.9%) MPZ mutation pedigrees and 1(1.0%) PMP22 mutation pedigree. In Chinese Han population, the proportion of PMP22 duplication was relatively lower than that in western countries and manifested with classical clinical characteristics of CMT. Subjects with axonal CMT often presented with isolated lower extremity injury and with central nervous system involvement. Hereditary motor neuropathy might be underestimated in clinical setting and should be differentiated from motor neuron disease. CONCLUSIONS: The gene frequency distribution in patients with CMT in Chinese Han population is different from that in patients from western countries. We should establish our own epidemiological data of CMT in Chinese Han population.

WNT10A variants are associated with non-syndromic tooth agenesis in the general population.

Tooth agenesis is the most common developmental dental anomaly. Absence of one or two permanent teeth is found in the majority of affected subjects. Very few patients suffer severe tooth agenesis. Recent studies revealed that WNT10A gene mutations caused syndromic and isolated severe tooth agenesis. In this study, to determine the contribution of WNT10A variants in different severities of tooth agenesis, we investigated the association between WNT10A variants and non-syndromic tooth agenesis in a Chinese population consisting of 505 tooth agenesis patients and 451 normal controls. Twenty-three novel non-synonymous variants were identified. WNT10A variants were detected in 15.8 % (75/474) of patients with 1-3 missing teeth and 51.6 % (16/31) of patients with 4 or more missing teeth. As compared with a frequency of 3.1 % in individuals with full dentition, variant allele frequencies were significantly elevated in both groups with tooth agenesis (p values of 1.00 × 10(-6) and 3.89 × 10(-23), respectively). Our findings showed that WNT10A variants were associated with non-syndromic tooth agenesis from mild to severe tooth agenesis, and the more severe tooth agenesis, the stronger association. Biallelic genotypes of WNT10A variants may have a pathogenic effect on tooth development. Presence of a single variant allele would be predisposing for causation with low penetrance. Together with WNT10A variant, there should be other genetic or environmental factors leading to biallelic variant-related variable clinical manifestations and single allele variant-related low penetrance. The frequent missing tooth positions in the WNT10A-related cases were consistent with that in the general population, suggesting WNT10A plays a critically important role in the etiology of general tooth agenesis.

Gestational organophosphate esters (OPEs) exposure in association with placental DNA methylation levels of peroxisome proliferator-activated receptors (PPARs) signaling pathway-related genes.

BACKGROUND: Organophosphate esters (OPEs) exposure could affect offspring health. However, the underlying mechanisms are not well documented. OBJECTIVES: Based on a birth cohort study, we aimed to investigate the associations among gestational OPEs exposure, placental DNA methylation levels of peroxisome proliferator-activated receptor (PPAR) signaling pathway-related genes, and fetal growth. METHODS: We measured the concentrations of eight OPE metabolites in maternal urine samples and neonatal anthropometric measurements in 733 mother-child pairs. In 327 placental samples, we assessed the DNA methylation levels of 14 genes which were involved in the PPARs signaling pathway and expressed in placenta. Multiple linear regression models were used to examine the associations of OPEs exposure with placental DNA methylation, and of OPEs and placental DNA methylation with neonatal anthropometric measurements. Causal mediation analyses were conducted to examine the potential mediating role of placental DNA methylation in the pathway between OPEs exposure and fetal growth. RESULTS: We observed a general pattern of OPEs exposure being associated with hypermethylation of candidate genes, with statistically significant associations identified for several OPEs with RXRA, ACAA1, ACADL, ACADM, PLTP, and NR1H3 methylation. Further, gestational exposure to BCIPP, DPP, BBOEP, ∑NCl-OPEs, and ∑OPEs tended to be associated with lower anthropometric measurements, with more significant associations observed on arm circumference, and abdominal and back skinfold thickness. Notably, RXRA, ACAA1, ACOX1, CPT2, ACADM, and NR1H3 methylation tended to be associated with lower neonatal anthropometric measurements, especially for abdominal and back skinfold thickness. Moreover, mediation analyses showed that 19.42 % of the total effect of DPP on the back skinfold thickness was mediated by changes in RXRA methylation, and there was a significant indirect effect of RXRA methylation. CONCLUSIONS: Gestational OPEs exposure could disrupt the placental DNA methylation levels of PPAR signaling pathway-related genes, which might contribute to the effect of OPEs on fetal growth.

Monkeypox presenting as a chancre-like rash: A case report.

BACKGROUND: Since May 2022, outbreaks of monkeypox have occurred in many countries around the world, and several cases have been reported in China. CASE SUMMARY: A 38-year-old man presented with a small, painless, shallow ulcer on the coronary groove for 8 d. One day after the rash appeared, the patient developed inguinal lymphadenopathy with fever. The patient had a history of male-male sexual activity and denied a recent history of travel abroad. Monkeypox virus was detected by quantitative polymerase chain reaction from the rash site and throat swab. Based on the epidemiological history, clinical manifestations and nucleic acid test results, the patient was diagnosed with monkeypox. CONCLUSION: Monkeypox is an emerging infectious disease in China. Monkeypox presenting as a chancre-like rash is easily misdiagnosed. Diagnosis can be made based on exposure history, clinical manifestations and nucleic acid test results.

A case-control study of the association between tooth-development gene polymorphisms and non-syndromic hypodontia in the Chinese Han population.

Hypodontia is one of the most common anomalies of human dentition. Recent genetic studies provide information on a number of genes related to both syndromic and non-syndromic forms of hypodontia. Fifty putative single nucleotide polymorphisms (SNPs) in 20 genes that play important roles in tooth development were selected, and a case-control study was conducted in 273 subjects with hypodontia (cases) and 200 subjects without hypodontia (controls). DNA was obtained from samples of whole blood or saliva. Genotyping was performed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). A significant difference was observed, between subjects with non-syndromic hypodontia and controls, in the allele and genotype frequencies of two markers [rs929387 of GLI family zinc finger 3 (GLI3) and rs11001553 of Dickkopf-related protein 1 (DKK1)]. Similar results were observed in a subgroup analysis of test subjects (stratified by gender or missing tooth position). However, this analysis showed no significant difference in the haplotype distribution between the controls and the affected subjects. These data demonstrate an association between some SNPs in tooth development-associated genes and sporadic non-syndromic hypodontia in Chinese Han individuals. This information may provide further understanding of the molecular mechanisms of tooth agenesis. Furthermore, these genes can be regarded as candidates for mutation detection in individuals with tooth agenesis.

Disturbed keratin expression and distinct genotype of ichthyosis hystrix Lambert type.

We have previously reported the second familial ichthyosis hystrix strongly resembling Lambert type in clinical features, now this family has expanded to three generations, including three patients and five unaffected individuals. The purpose of this study was to investigate the molecular basis of this family. Paraffin-embedded skin sections were stained using keratin 1 (K1), K2, K10, K5+14 and loricrin antibodies. Genomic DNA isolated from blood samples was used to carry out a polymerase-chain-reaction. Immunohistochemistry showed that the distributions, but not the densities of K1/K2/K10 were dramatically changed in the patients. Unlike normal expression of K1/K10 from suprabasal layers and K2 from upper spinous layers, K1/K10 was expressed later from upper spinous layers and K2 was expressed earlier from basal layers; and they were densely aggregated around the nucleus rather than the normal regular distribution in the cytoplasm. DNA sequencing did not reveal any pathogenic mutations in candidate genes (KRT1, KRT2, KRT10 and plakoglobin) in keratin gene clusters. Linkage analysis also excluded the possibility of causative mutations in the epidermal differentiation complex on 1q, desmoplakin gene on 6p and desmosomal cadherin gene cluster on 18q regions. Other genes encoding proteins interacting with keratins might be pathogenic in this rare disease and should be studied further.

[A new EXT2 mutation in a Chinese family with hereditary multiple exostoses].

OBJECTIVE: Hereditary multiple exostoses (HME) is an autosomal dominant disorder characterized by formation of benign cartilage-capped tumors (exostoses), typically located at the juxtaepiphyseal regions of long bones. It is genetically heterogeneous with at least three chromosomal loci: EXT1 on 8q24.1, EXT2 on 11p11, and EXT3 on 19p. EXT1 and EXT2 have been cloned and are responsible for over 80% of cases. A Chinese family with HME has been analyzed in the present study. METHODS: Linkage analysis was firstly performed to determine which of the three EXT genes could be the candidate gene, then mutation screening by PCR and direct sequencing was carried out. RESULTS: A novel nonsense mutation (c.1006C>T) in exon 6 of EXT2, which converts the codon CAA (Gln) to the stop codon (TAA) (Gln336X), was identified. Next, prenatal diagnosis was performed and the pregnancy was determined to be normal. CONCLUSION: A new EXT2 nonsense mutation was found in a Chinese family with hereditary multipe exostoses. The information was used for a case of prenatal diagnosis.

ALOX12 is required for p53-mediated tumour suppression through a distinct ferroptosis pathway.

It is well established that ferroptosis is primarily controlled by glutathione peroxidase 4 (GPX4). Surprisingly, we observed that p53 activation modulates ferroptotic responses without apparent effects on GPX4 function. Instead, ALOX12 inactivation diminishes p53-mediated ferroptosis induced by reactive oxygen species stress and abrogates p53-dependent inhibition of tumour growth in xenograft models, suggesting that ALOX12 is critical for p53-mediated ferroptosis. The ALOX12 gene resides on human chromosome 17p13.1, a hotspot of monoallelic deletion in human cancers. Loss of one Alox12 allele is sufficient to accelerate tumorigenesis in Eµ-Myc lymphoma models. Moreover, ALOX12 missense mutations from human cancers abrogate its ability to oxygenate polyunsaturated fatty acids and to induce p53-mediated ferroptosis. Notably, ALOX12 is dispensable for ferroptosis induced by erastin or GPX4 inhibitors; conversely, ACSL4 is required for ferroptosis upon GPX4 inhibition but dispensable for p53-mediated ferroptosis. Thus, our study identifies an ALOX12-mediated, ACSL4-independent ferroptosis pathway that is critical for p53-dependent tumour suppression.

[Association between mitochondrial DNA mutations and cancer in human].

Mitochondria are essential organelles that generate cellular energy in cells. Mutations of mitochondrial DNA (mtDNA) have been identified in various types of cancer, suggesting a complex relationship between mtDNA and cancer. This review focuses on the possible correlation between the mtDNA mutation and cancer. Additionally, possible causes for mtDNA mutations and applications for detecting mtDNA mutations in cancer are discussed.

Effects of Parental Migration on Life Satisfaction and Academic Achievement of Left-Behind Children in Rural China-A Case Study in Hubei Province.

In the rural areas of China, there is a high occurrence of parental migration, wherein adults are flushed into urban areas to search for employment opportunities, leading to millions of left-behind children (LBC) in rural China. LBC attracts more attention from the social community and Chinese government. Here, we compared the life satisfaction and academic achievement of left-behind children (LBC) and non-left-behind children (NLBC) in rural regions that send out migrant labor in Hubei province, central China. We investigated 1031 LBC and 992 NLBC students in grades 4 to 9 in ten elementary and four middle schools, using a structured questionnaire including sociodemographic characteristics, life satisfaction, and academic achievement scores. The results showed that LBC have a lower life satisfaction and lower academic achievement than NLBC (p < 0.01). Meanwhile, as the child’s age at separation from parents decreased, their life satisfaction decreased. Additionally, correlations were observed between life satisfaction and academic achievement scores in LBC (p = 0.004) as well as in NLBC (p = 0.064). Collectively, these findings provide novel insights into a comprehensive understanding of LBC and suggest that the life satisfaction levels of LBC should be improved in rural China.

Deletion of exon 4 in LAMA2 is the most frequent mutation in Chinese patients with laminin α2-related muscular dystrophy.

Although recessive mutations in LAMA2 are already known to cause laminin α2-related muscular dystrophy, a rare neuromuscular disorder, large deletions or duplications within this gene are not well-characterized. In this study, we applied next-generation sequencing-based copy number variation profiling in 114 individuals clinically diagnosed with laminin α2-related muscular dystrophy, including 96 who harboured LAMA2 mutations and 34 who harboured intragenic rearrangements. In total, we detected 18 distinct LAMA2 copy number variations that have been reported only among Chinese, 10 of which are novel. The frequency of CNVs in the cohort was 19.3%. Deletion of exon 4 was detected in 10 alleles of eight patients, accounting for 27% of all copy number variations. These patients are Han Chinese and were found to have the same haplotype and sequence at the breakpoint junction, suggesting that exon 4 deletion is a founder mutation in Chinese Han and a mutation hotspot. Moreover, the data highlight our approach, a modified next-generation sequencing assay, as a robust and sensitive tool to detect LAMA2 variants; the assay identifies 85.7% of breakpoint junctions directly alongside sequence information. The method can be applied to clinical samples to determine causal variants underlying various Mendelian disorders.

Quantification of dibromodimethylhydantoin disinfectants in water by chemiluminescent method.

Quantification of 1,3-dibromo-5,5-dimethylhydantoin (DBDMH) was studied by its chemiluminescence (CL) reaction with luminol in an alkaline medium. The stability of DBDMH, 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) and 1-bromo-3-chloro-5,5-dimethylhydantoin (BCDMH) in water was initially assessed by its CL reaction capability. The results indicated that the hydrolysis process was critically dependent on the types of reagents and their pHs. Capillary electrophoresis (CE) separation with CL detection procedure was applied to the DBDMH solution. It was found that at least 3 species in the aqueous DBDMH solution could oxidize luminol to give luminescence: one of them was confirmed to be hypobromite and the others could be the unhydrolyzed or active oxygen produced in the hydrolysis reaction. Finally, a flow-injection chemiluminescent method was proposed for the determination of DBDMH. The concentration of the analyte showed a linear relationship with the CL intensity in the range of 1.2x10(-10) to 1.0x10(-6) mol dm-3 and the detection limit was as low as 6.2x10(-11) mol dm-3. The relative standard deviation (RSD) is 1.7% (n=9) for 2.8x10(-7) mol dm-3 DBDMH.

[The same mutation Glu208Lys in the GJB1 gene was detected in 2 families with X-linked Charcot-Marie-Tooth disease].

Mutation of GJB1 gene was investigated in two families with X-linked Charcot-Marie-Tooth disease. Genomic DNA from venous blood samples was prepared. The coding sequence of the GJB1 gene was amplified from genomic DNA. PCR products were analyzed by single strand conformational polymorphism (SSCP) method. The PCR product having an abnormal pattern was sequenced to detect the mutation. It was found that the samples of all patients and one little girl with normal phenotype showed an abnormal SSCP band, but not detected in the other unaffected members in the first large family. In the second small family, an abnormal SSCP band was found in all the patients, but not detected in the unaffected member. The result of DNA sequencing demonstrated that both families had a same mutation of 622G-->A, which resulted in a substitution of Glu208Lys. This mutation has not been reported previously in China.

No mutation was detected in the LMNA gene among sporadic Charcot-Marie-Tooth patients.

OBJECTIVE: To intensively investigate sporadic CMT patients, we have analyzed the LMNA gene in this study in a series of 32 unrelated CMT patients. METHODS: Twelve exons of the LMNA gene were amplified from genetic DNA. PCR products of each exon were analyzed by single strand conformational polymorphism (SSCP). RESULTS: No abnormal SSCP pattern, suggesting no mutation in our CMT patients, was detected. CONCLUSION: The CMT diseases resulted from the mutations of LMNA gene were rare.

A novel PAX6 gene mutation in a Chinese family with aniridia.

PURPOSE: The PAX6 gene mutation in aniridia has been studied in various ethnic patients, but not well studied in the Chinese population. In the present study, we have investigated the PAX6 gene mutation in a Chinese family with congenital aniridia. METHODS: Total genomic DNA was isolated from peripheral blood of three aniridia patients (who also suffered from bilateral congenital cataracts) and two non-carriers in a Chinese family. Fourteen exons of the PAX6 gene were amplified by polymerase chain reaction (PCR). PCR products of each exon were analyzed by single strand conformational polymorphism (SSCP). The PCR products with abnormal SSCP patterns were subcloned and sequenced to identify the mutation. RESULTS: Abnormal SSCP patterns were found in all affected patients but not in non-carrier family members. A novel mutation (c.857delG) in exon 7 was detected by sequencing analysis. This frame shift mutation was predicted to lead to a pre-stop codon in exon 8, and generate a novel 40 amino acid peptide from codon 165. CONCLUSIONS: A novel PAX6 gene mutation was identified in a Chinese aniridia family. This mutation may also contribute to congenital cataracts in these aniridia patients.