Proteomics of Salt Gland-Secreted Sap Indicates a Pivotal Role for Vesicle Transport and Energy Metabolism in Plant Salt Secretion.

Soil salinization is one of the major factors restricting crop growth and agricultural production worldwide. Recretohalophytes have developed unique epidermal structures in their aboveground tissues, such as salt glands or salt bladders, to secrete excess salt out of the plant body as a protective mechanism from ion damage. Three hypotheses were proposed to explain how salt glands secrete salts: the osmotic hypothesis, a hypothesis similar to animal fluid transport, and vesicle-mediated exocytosis. However, there is no direct evidence to show whether the salt gland-secreted liquid contains landmark proteins or peptides which would elucidate the salt secretion mechanism. In this study, we collected the secreted liquid of salt glands from Limonium bicolor, followed by extraction and identification of its constituent proteins and peptides by SDS-PAGE and mass spectrometry. We detected 214 proteins and 440 polypeptides in the salt gland-secreted droplets of plants grown under control conditions. Unexpectedly, the proportion of energy metabolism-related proteins increased significantly though only 16 proteins and 35 polypeptides in the droplets of salt-treated plants were detected. In addition, vesicle transport proteins such as the Golgi marker enzyme glycosyltransferase were present in the secreted sap of salt glands from both control and salt-treated plants. These results suggest that trans-Golgi network-mediated vesicular transport and energy production contributes to salt secretion in salt glands.

Prevalence and Clinical Characteristics of Fabry Disease in Chinese Patients With Hypertrophic Cardiomyopathy.

BACKGROUND: The prevalence of Fabry disease (FD) in Chinese patients with hypertrophic cardiomyopathy (HCM) is unclear. We aimed to evaluate the prevalence, clinical characteristics, and outcomes of FD in Chinese patients with HCM. METHODS: Of 217 patients with HCM, FD probands were screened by next-generation sequencing at Fuwai Hospital. Medical data from α-galactosidase A activity, electrocardiography, echocardiography, coronary angiography, cardiac magnetic resonance, pathological examination, and follow up was analyzed. RESULTS: Two FD probands were observed (0.93% of patients with HCM), both of which were diagnosed with symptomatic obstructive HCM at 49 years of age. One proband had a GLA mutation (c.887T>C [p.M296T]) with a late-onset cardiac variant, which was characterized by dual ventricular hypertrophy and conduction disease with a permanent pacemaker. The other patient had a GLA mutation (c.758T>C [p.I253T]) with a classic phenotype and dual ventricular hypertrophy, atrioventricular block, renal failure, and recurrent cerebral infarction. Both probands had late gadolinium enhancement mainly in the basal segment of the inferolateral wall. Follow up revealed no exertional symptoms or outflow obstruction after surgical septal myectomy in the two probands, and stable renal function was observed after 6 months of migalastat therapy in the later one. A family study revealed six female carriers and three sudden cardiac deaths. CONCLUSIONS: FD is not uncommon in Chinese patients with HCM. Multiple organic involvement, dual ventricular hypertrophy, and conduction disease provide clinical clues for suspected FD, and early genetic screening is necessary. Surgical septal myectomy and migalastat improve the long-term prognosis of patients with FD.

Heterologous expression of the Limonium bicolor MYB transcription factor LbTRY in Arabidopsis thaliana increases salt sensitivity by modifying root hair development and osmotic homeostasis.

Arabidopsis thaliana TRY is a negative regulator of trichome differentiation that promotes root hair differentiation. Here, we established that LbTRY, from the recretohalophyte Limonium bicolor, is a typical MYB transcription factor that exhibits transcriptional activation activity and locates in nucleus. By in situ hybridization in L. bicolor, LbTRY may be specifically positioned in salt gland of the expanded leaves. LbTRY expression was the highest in mature leaves and lowest under NaCl treatment. For functional assessment, we heterologously expressed LbTRY in wild-type and try29760 mutant Arabidopsis plants. Epidermal differentiation was remarkably affected in the transgenic wild-type line, as was increased root hair development. Complementation of try29760 with LbTRY under both 35S and LbTRY specific promoter restored the wild-type phenotype. qRT-PCR analysis suggested that AtGL3 and AtZFP5 promote root hair cell fate in lines heterologously producing LbTRY. In addition, four genes (AtRHD6, AtRSL1, AtLRL2, and AtLRL3) involved in root hair initiation and elongation were upregulated in the transgenic lines. Furthermore, LbTRY specifically increased the salt sensitivity of the transgenic lines. The transgenic and complementation lines showed poor germination rates and reduced root lengths, whereas the mutant unexpectedly fared the best under a range of NaCl treatments. Under salt stress, the transgenic seedlings accumulated more MDA and Na+ and less proline and soluble sugar than try29760. Thus, when heterologously expressed in Arabidopsis, LbTRY participates in hair development, similar to other MYB proteins, and specifically reduces salt tolerance by increasing ion accumulation and reducing osmolytes. The expression of salt-tolerance marker genes (SOS1, SOS2, SOS3 and P5CS1) was significant reduced in the transgenic lines. More will be carried by downregulating expression of TRY homologs in crops to improve salt tolerance.

Genotypic and phenotypic characterization of Chinese patients with osteogenesis imperfecta.

Osteogenesis imperfecta (OI) is a rare hereditary skeletal dysplasia, characterized by recurrent fractures and bone deformity. This study presents a clinical characterization and mutation analysis of 668 patients, aiming to establish the mutation spectrum and to elucidate genotype-phenotype correlations in Chinese OI patients. We identified 274 sequence variants (230 in type I collagen encoding genes and 44 in noncollagen genes), including 102 novel variants, in 340 probands with a detection rate of 90%. Compared with 47 loss-of-function variants detected in COL1A1, neither nonsense nor frameshift variants were found in COL1A2 (p < 0.0001). The major cause of autosomal recessive OI was biallelic variants in WNT1 (56%, 20/36). It is noteworthy that three genomic rearrangements, including one gross deletion and one gross duplication in COL1A1 as well as one gross deletion in FKBP10, were detected in this study. Of ten individuals with glycine substitutions that lie towards the N-terminal end of the triple-helical region of the α1(I) chain, none exhibited hearing loss, suggesting a potential genotype-phenotype correlation. The findings in this study expanded the mutation spectrum and identified novel correlations between genotype and phenotype in Chinese OI patients.

Molecular analysis of inherited cardiomyopathy using next generation semiconductor sequencing technologies.

BACKGROUND: Cardiomyopathies are the most common clinical and genetic heterogeneity cardiac diseases, and genetic contribution in particular plays a major role in patients with primary cardiomyopathies. The aim of this study is to investigate cases of inherited cardiomyopathy (IC) for potential disease-causing mutations in 64 genes reported to be associated with IC. METHODS: A total of 110 independent cases or families diagnosed with various primary cardiomyopathies, including hypertrophic cardiomyopathy, dilated cardiomyopathy, restrictive cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, left ventricular non-compaction, and undefined cardiomyopathy, were collected after informed consent. A custom designed panel, including 64 genes, was screened using next generation sequencing on the Ion Torrent PGM platform. The best candidate disease-causing variants were verified by Sanger sequencing. RESULTS: A total of 78 variants in 73 patients were identified. After excluding the variants predicted to be benign and VUS, 26 pathogenic or likely pathogenic variants were verified in 26 probands (23.6%), including a homozygous variant in the SLC25A4 gene. Of these variants, 15 have been reported in the Human Gene Mutation Database or ClinVar database, while 11 are novel. The majority of variants were observed in the MYH7 (8/26) and MYBPC3 (6/26) gene. Titin (TTN) truncating mutations account for 13% in our dilated cardiomyopathy cases (3/23). CONCLUSIONS: This study provides an overview of the genetic aberrations in this cohort of Chinese IC patients and demonstrates the power of next generation sequencing in IC. Genetic results can provide precise clinical diagnosis and guidance regarding medical care for some individuals.

RNF213 as the major susceptibility gene for Chinese patients with moyamoya disease and its clinical relevance.

OBJECTIVE Moyamoya disease (MMD) is a rare, genetically heterogeneous cerebrovascular disease. The authors conducted a genetic study of really interesting new gene (RING) finger protein 213 ( RNF213); actin alpha 2 ( ACTA2); BRCA1/BRCA2-containing complex subunit 3 ( BRCC3); and guanylate cyclase 1, soluble, alpha 3 ( GUCY1A3) as well as a clinical phenotype analysis in Chinese MMD patients to determine whether genetic differences are responsible for the different clinical features that appear in MMD in different ethnicities. METHODS A panel was designed to identify disease-causing mutations in MMD genes and those involved in related disorders ( RNF213, ACTA2, BRCC3, and GUCY1A3). The panel was used to detect disease-causing mutations in 255 Chinese MMD patients. Genotype and allele frequencies were compared between patients and 300 controls. A mutation segregation analysis was performed in 34 families, and genotype-phenotype correlations were made. RESULTS Twenty-seven rare missense variants of RNF213 were identified and were not found in controls. Among them, p.R4810K was identified in 31.4% of patients (80 of 255) with MMD. Significantly higher frequencies of the A allele and G/A genotype of p.R4810K were observed in MMD patients compared with controls (χ2 = 104.166, p < 0.000). Twenty-five rare variants were identified in 10.6% of patients (27 of 255) without p.R4810K variants. Segregation analysis supported an association between MMD and 3 variants. No possible disease-causing mutations were identified in ACTA2, BRCC3, or GUCY1A3. Compared with patients without the rare variants in RNF213, the p.R4810K heterozygous patients were younger at diagnosis (25 vs 29 years old, p = 0.049) and had more familial cases (24% vs 4.4%, p = 0.000), ischemic cases (81.3% vs 67.5%, p = 0.037), and involvement of the posterior cerebral artery (52% vs 32.5%, p = 0.007). CONCLUSIONS RNF213 is the major susceptibility gene in Chinese MMD patients. The spectrum of rare variants identified in Chinese MMD patients was diverse. Compared to patients without the rare variants in RNF213, the p.R4810K heterozygous patients exhibited different clinical features.

Restrictive Cardiomyopathy Resulting from a Troponin I Type 3 Mutation in a Chinese Family.

Objective To identify the pathogenic variant responsible for restrictive cardiomyopathy (RCM) in a Chinese family.Methods Next generation sequencing was used for detecting the mutation and Results verified by sequencing. We used restriction enzyme digestion to test the mutation in the family members and 200 unrelated normal subjects without any cardiac inherited diseases when the mutation was identified.Results Five individuals died from cardiac diseases, two of whom suffered from sudden cardiac death. Two individuals have suffered from chronic cardiac disorders. Mutation analysis revealed a novel missense mutation in exon 7 of troponin I type 3 (TNNI3), resulting in substitution of serine (S) with proline (P) at amino acid position 150, which cosegregated with the disease in the family, which is predicted to be probably damaging using PolyPhen-2. The mutation was not detected in the 200 unrelated subjects we tested.Conclusion Using next generation sequencing, which has very recently been shown to be successful in identifying novel causative mutations of rare Mendelian disorders, we found a novel mutation of TNNI3 in a Chinese family with RCM.

[Diagnosis of glycogen storage disease type IIIA by detecting glycogen debranching enzyme activity, glycogen content and structure in muscle].

OBJECTIVE: Glycogen storage disease type III (GSD III) is an autosomal recessive disease caused by glycogen debranching enzyme (GDE) gene (AGL gene) mutation resulting in hepatomegaly, hypoglycemia, short stature and hyperlipidemia. GSD IIIA, involves both liver and muscle, and accounts for up to 80% of GSD III. The definitive diagnosis depends on either mutation analysis or liver and muscle glycogen debranching enzyme activity tests. This study aimed to establish enzymologic diagnostic method for GSD IIIA firstly in China by detecting muscular GDE activity, glycogen content and structure and to determine the normal range of muscular GDE activity, glycogen content and structure in Chinese children. METHOD: Muscle samples were collected from normal controls (male 15, female 20; 12-78 years old), molecularly confirmed GSD III A patients (male 8, female 4, 2-27 years old) and other myopathy patients (male 9, 2-19 years old). Glycogen in the muscle homogenate was degraded into glucose by amyloglucosidase and phosphorylase respectively. The glycogen content and structure were identified by glucose yield determination. The debranching enzyme activity was determined using limit dextrin as substrate. Independent samples Kruskal-Wallis H test, Nemenyi-Wilcoxson-Wilcox test, and Chi-square test were used for statistical analyses by SPSS 11.5. RESULT: (1) GSD III A patients' glycogen content were higher, but G1P/G ratio and GDE activity were lower than those of the other two groups (P < 0.01). In all of the three parameters, there were no significant difference between normal controls and other myopathy patients. (2) The range of normal values: glycogen content 0.31%-0.43%, G1P/G ratio 22.37%- 26.43%, GDE activity 0.234-0.284 micromol/(g. min). (3) Enzymologic diagnostic method had a power similar to that of gene analysis in diagnosis of GSD-IIIA patients. The sensitivity and specificity of enzymologic diagnostic method and mutation detection were 91.7% and 100% respectively. CONCLUSION: Enzymologic diagnostic method of GSD IIIA was firstly established in China. The range of normal values was determined. This method could be used in diagnosing suspected GSD IIIA patients in the clinic.

[Identification of a novel TP53 germline mutation in one child with adrenocortical carcinoma].

OBJECTIVE: To detect the germline TP53 gene mutation in a child with pediatric adrenocortical carcinoma (ADCC) in order to provide genetic diagnosis and counseling. METHODS: Genomic DNA was extracted from peripheral blood from a girl with ADCC and her parents. All TP53 exons and their flanking intronic sequences were PCR-amplified and subjected to automatic DNA sequencing. RESULTS: Direct sequencing of PCR products revealed a heterozygous G insertion between nucleotide 522 and 523 (c.522-523insG) in TP53 exon 5. This novel mutation is predicted to result in a frame shift at codon 175, producing a new reading frame ending in a stop at position 6 (p.R175AfsX6). The same heterozygous mutation was also found in her father, but not in her mother. CONCLUSION: A novel germline mutation in the TP53 gene has been identified in one case with pediatric ADCC.