BackgroundModern medicine often clashes with traditional medicine such as Chinese herbal medicine because of the little understanding of the underlying mechanisms of action of the herbs. In an effort to promote integration of both sides and to accelerate the drug discovery from herbal medicines, an efficient systems pharmacology platform that represents ideal information convergence of pharmacochemistry, ADME properties, drug-likeness, drug targets, associated diseases and interaction networks, are urgently needed.DescriptionThe traditional Chinese medicine systems pharmacology database and analysis platform (TCMSP) was built based on the framework of systems pharmacology for herbal medicines. It consists of all the 499 Chinese herbs registered in the Chinese pharmacopoeia with 29,384 ingredients, 3,311 targets and 837 associated diseases. Twelve important ADME-related properties like human oral bioavailability, half-life, drug-likeness, Caco-2 permeability, blood-brain barrier and Lipinski’s rule of five are provided for drug screening and evaluation. TCMSP also provides drug targets and diseases of each active compound, which can automatically establish the compound-target and target-disease networks that let users view and analyze the drug action mechanisms. It is designed to fuel the development of herbal medicines and to promote integration of modern medicine and traditional medicine for drug discovery and development.ConclusionsThe particular strengths of TCMSP are the composition of the large number of herbal entries, and the ability to identify drug-target networks and drug-disease networks, which will help revealing the mechanisms of action of Chinese herbs, uncovering the nature of TCM theory and developing new herb-oriented drugs. TCMSP is freely available at http://sm.nwsuaf.edu.cn/lsp/tcmsp.php.
Oculopharyngodistal myopathy (OPDM) is an adult-onset neuromuscular disease characterized by progressive ocular, facial, pharyngeal and distal limb muscle involvement. Trinucleotide repeat expansions in LRP12 or GIPC1 were recently reported to be associated with OPDM. However, a significant portion of OPDM patients have unknown genetic causes. In this study long-read whole-genome sequencing and repeat-primed polymerase chain reaction were performed and we identified GGC repeat expansions in the NOTCH2NLC gene in 16.7% (4/24) of a cohort of Chinese OPDM patients, designated as OPDM type 3 (OPDM3). Methylation analysis indicated that methylation levels of the NOTCH2NLC gene were unaltered in OPDM3 patients, but increased significantly in asymptomatic carriers. Quantitative real-time PCR analysis indicated that NOTCH2NLC mRNA levels were increased in muscle but not in blood of OPDM3 patients. Immunofluorescence on OPDM muscle samples and expressing mutant NOTCH2NLC with (GGC)69 repeat expansions in HEK293 cells indicated that mutant NOTCH2NLC-polyGlycine protein might be a major component of intranuclear inclusions, and contribute to toxicity in cultured cells. In addition, two RNA-binding proteins, hnRNP A/B and MBNL1, were both co-localized with p62 in intranuclear inclusions in OPDM muscle samples. These results indicated that a toxic protein gain-of-function mechanism and RNA gain-of-function mechanism may both play a vital role in the pathogenic processes of OPDM3. This study extended the spectrum of NOTCH2NLC repeat expansion related diseases to a predominant myopathy phenotype presenting as OPDM, and provided evidence for possible pathogenesis of these diseases.
BackgroundNeuronal intranuclear inclusion disease (NIID) is a heterogenous neurodegenerative disorder named after its pathological features. It has long been considered a disease of genetic origin. Recently, the GGC repeated expansion in the 5′-untranslated region (5′UTR) of the NOTCH2NLC gene has been found in adult-onset NIID in Japanese individuals. This study was aimed to investigate the causative mutations of NIID in Chinese patients.MethodsFifteen patients with NIID were identified from five academic neurological centres. Biopsied skin samples were analysed by histological staining, immunostaining and electron microscopic observation. Whole-genome sequencing (WGS) and long-read sequencing (LRS) were initially performed in three patients with NIID. Repeat-primed PCR was conducted to confirm the genetic variations in the three patients and the other 12 cases.ResultsOur patients included 14 adult-onset patients and 1 juvenile-onset patient characterised by degeneration of multiple nervous systems. All patients were identified with intranuclear inclusions in the nuclei of fibroblasts, fat cells and ductal epithelial cells of sweat glands. The WGS failed to find any likely pathogenic variations for NIID. The LRS successfully identified that three patients with adult-onset NIID showed abnormalities of GGC expansion in 5′UTR of the NOTCH2NLC gene. The GGC repeated expansion was further confirmed by repeat-primed PCR in seven familial cases and eight sporadic cases.ConclusionOur findings provided evidence that confirmed the GGC repeated expansion in the 5′UTR of the NOTCH2NLC gene is associated with the pathogenesis of NIID. Additionally, the GGC expansion was not only responsible for adult-onset patients, but also responsible for juvenile-onset patients.
BackgroundGGC repeat expansion in NOTCH2NLC has been recently linked to neuronal intranuclear inclusion disease (NIID) via unknown disease mechanisms. Herein, we explore the genetic origin of the sporadic cases and toxic RNA gain-of-function mechanism in NIID.MethodsMultiple genetic screenings were performed on NIID individuals and their available family members. Methylation status of blood DNA, NOTCH2NLC mRNA level from muscle biopsies and RNA foci from skin biopsies of NIID individuals or asymptomatic carriers were evaluated and compared.ResultsIn two sporadic NIID families, we identified two clinically and pathologically asymptomatic fathers carrying large GGC repeat expansion, above 300 repeats, with offspring repeat numbers of 172 and 148, respectively. Further evaluation revealed that the GGC repeat numbers in the sperm from two asymptomatic fathers were only 63 and 98, respectively. The CpG island in NOTCH2NLC of the asymptomatic carriers was hypermethylated, and accordingly, the NOTCH2NLC mRNA levels were decreased in the asymptomatic fathers. GGC repeat expansion RNA formed RNA foci and sequestered RNA binding proteins into p62 positive intranuclear inclusions in NIID individuals but not in the control or asymptomatic carrier.ConclusionOur study suggested the GGC repeat expansion in NOTCH2NLC might have a disease-causing number ranging from ~41 to ~300 repeats. The contraction of GGC repeat expansion in sperm could be a possible mechanism for the paternal-biased origin in some sporadic or recessive inherited NIID individuals. The toxic RNA gain-of-function mechanism was identified to be involved in the pathogenicity of this disease.
PurposeFacioscapulohumeral muscular dystrophy (FSHD) is a common adult muscular dystrophy. Over 95% of FSHD cases are associated with contraction of the D4Z4 tandem repeat (~3.3 kb per unit) at 4q35 with a specific genomic configuration (haplotype) called 4qA. Molecular diagnosis of FSHD typically requires pulsed-field gel electrophoresis with Southern blotting. We aim to develop novel genomic and computational methods for characterising D4Z4 repeat numbers in FSHD.MethodsWe leveraged a single-molecule optical mapping platform that maps locations of restriction enzyme sites on high molecular weight (>150 kb) DNA molecules. We developed bioinformatics methods to address several challenges, including the differentiation of 4qA with 4qB alleles, the differentiation of 4q35 and 10q26 segmental duplications, the quantification of repeat numbers with different enzymes that may or may not have recognition sites within D4Z4 repeats. We evaluated the method on 25 human subjects (13 patients, 3 individual control subjects, 9 control subjects from 3 families) labelled by the Nb.BssSI and/or Nt.BspQI enzymes.ResultsWe demonstrated that the method gave a direct quantitative measurement of repeat numbers on D4Z4 repeats with 4qA allelic configuration and the levels of postzygotic mosaicism. Our method had high concordance with Southern blots from several cohorts on two platforms (Bionano Saphyr and Bionano Irys), but with improved quantification of repeat numbers.ConclusionWhile the study is limited by small sample size, our results demonstrated that single-molecule optical mapping is a viable approach for more refined analysis on genotype-phenotype relationships in FSHD, especially when postzygotic mosaicism is present.
The development of next generation sequencing (NGS) platform-based single-cell RNA sequencing (scRNA-seq) techniques has tremendously changed biological researches, while there are still many questions that cannot be addressed by them due to their short read lengths. We developed a novel scRNA-seq technology based on third-generation sequencing (TGS) platform (single-cell amplification and sequencing of full-length RNAs by Nanopore platform, SCAN-seq). SCAN-seq exhibited high sensitivity and accuracy comparable to NGS platform-based scRNA-seq methods. Moreover, we captured thousands of unannotated transcripts of diverse types, with high verification rate by reverse transcription PCR (RT-PCR)–coupled Sanger sequencing in mouse embryonic stem cells (mESCs). Then, we used SCAN-seq to analyze the mouse preimplantation embryos. We could clearly distinguish cells at different developmental stages, and a total of 27,250 unannotated transcripts from 9,338 genes were identified, with many of which showed developmental stage-specific expression patterns. Finally, we showed that SCAN-seq exhibited high accuracy on determining allele-specific gene expression patterns within an individual cell. SCAN-seq makes a major breakthrough for single-cell transcriptome analysis field.
Background: The expansion of GGC repeat in the 5' untranslated region of the NOTCH2NLC has been associated with various neurogenerative disorders of the central nervous system and, more recently, oculopharyngodistal myopathy. This study aimed to report patients with distal weakness with both neuropathic and myopathic features on electrophysiology and pathology who present GGC repeat expansions in the NOTCH2NLC. Methods: Whole-exome sequencing (WES) and long-read sequencing were implemented to identify the candidate genes. In addition, the available clinical data and the pathological changes associated with peripheral nerve and muscle biopsies were reviewed and studied. Results: We identified and validated GGC repeat expansions of NOTCH2NLC in three unrelated patients who presented with progressive weakness predominantly affecting distal lower limb muscles, following negative results in an initial WES. We found intranuclear inclusions with multiple proteins deposits in the nuclei of both myofibers and Schwann cells. The clinical features of these patients are compatible with the diagnosis of distal motor neuropathy and rimmed vacuolar myopathy. Interpretation: These phenotypes enrich the class of features associated with NOTCH2NLC-related repeat expansion disorders (NRED), and provide further evidence that the neurological symptoms of NRED include not only brain, spinal cord, and peripheral nerves damage, but also myopathy, and that overlapping symptoms might exist.
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