Aging is the most important risk factor associated with Alzheimer's disease (AD); however, the molecular mechanisms linking aging to AD remain unclear. Suppression of the ribosomal protein S6 kinase 1 (S6K1) increases healthspan and lifespan in several organisms, from nematodes to mammals. Here we show that S6K1 expression is upregulated in the brains of AD patients. Using a mouse model of AD, we found that genetic reduction of S6K1 improved synaptic plasticity and spatial memory deficits, and reduced the accumulation of amyloid-β and tau, the two neuropathological hallmarks of AD. Mechanistically, these changes were linked to reduced translation of tau and the β-site amyloid precursor protein cleaving enzyme 1, a key enzyme in the generation of amyloid-β. Our results implicate S6K1 dysregulation as a previously unidentified molecular mechanism underlying synaptic and memory deficits in AD. These findings further suggest that therapeutic manipulation of S6K1 could be a valid approach to mitigate AD pathology.
SIGNIFICANCE STATEMENT Aging is the most important risk factor for Alzheimer's disease (AD). However, little is known about how it contributes to AD pathogenesis. S6 kinase 1 (S6K1) is a protein kinase involved in regulation of protein translation. Reducing S6K1 activity increases lifespan and healthspan. We report the novel finding that reducing S6K1 activity in 3xTg-AD mice ameliorates synaptic and cognitive deficits. These improvement were associated with a reduction in amyloid-β and tau pathology. Mechanistically, lowering S6K1 levels reduced translation of β-site amyloid precursor protein cleaving enzyme 1 and tau, two key proteins involved in AD pathogenesis. These data suggest that S6K1 may represent a molecular link between aging and AD. Given that aging is the most important risk factor for most neurodegenerative diseases, our results may have far-reaching implications into other diseases.
Aβ; AD; aging; mTOR; plaques; tangles
AIM: To investigate multiple polyps in a Chinese Peutz-Jeghers syndrome (PJS) infant.
METHODS: A nine-month-old PJS infant was admitted to our hospital for recurrent prolapsed rectal polyps for one month. The clinical characteristics, a colonoscopic image, the pathological characteristics of the polyps and X-ray images of the intestinal perforation were obtained. Serine threonine-protein kinase 11 (STK11) gene analysis was also performed using a DNA sample from this infant.
RESULTS: Here we describe the youngest known Chinese infant with PJS. Five polyps, including a giant polyp of approximately 4 cm × 2 cm in size, were removed from the infant’s intestine. Laparotomy was performed to repair a perforation caused by pneumoperitoneum. The pathological results showed that this child had PJS. Molecular analysis of the STK11 gene further revealed a novel frameshift mutation (c.64_65het_delAT) in exon 1 in this PJS infant.
CONCLUSION: The appropriate treatment method for multiple polyps in an infant must be carefully considered. Our results also show that the STK11 gene mutation is the primary cause of PJS.
Peutz-Jeghers syndrome; Perforation; STK11 gene; Chinese infant; Polyps
To evaluate physiological roles of the large, second cytoplasmic loops (C2) situated between the M3 and M4 transmembrane domains of nicotinic acetylcholine receptor (nAChR) subunits. We have constructed chimeric β2 (β2χ) and β4 (β4χ) subunits in which the “nested” C2 domains (but not the “proximal” sequences of ~14 residues immediately adjacent to the M3 or M4 domains) of these β subunits were replaced by the corresponding sequence from the serotonin 5-HT3A receptor subunit. We previously reported that heterologously expressed nAChR containing α4 and β2χ subunits displayed a faster whole-cell current decay in its agonist response compared to responses of all-wild-type α4β2-nAChR. This suggests an unexpected, functional role for the C2 domain of the β2 subunit in α4β2-nAChR acute desensitization. Here we report that there also is faster desensitization of α4β4χ-nAChR relative to α4β4-nAChR stably and heterologously expressed in the human SH-EP1 cell-line. In addition, cell-attached, single channel recording shows that both acetylcholine-activated α4β2χ- and α4β4χ-nAChR have a significantly lower mean open probability, shorter mean open-time, and a longer mean closed-time than their fully wild-type counterparts while not having different conductance amplitudes. These findings reveal microscopic bases for the faster desensitization of α4*-nAChR containing chimeric instead of wild-type β subunits. Our findings also remain consistent with novel and unexpected roles of β subunit nested C2 domains in modulation of α4*-nAChR function.
nicotinic acetylcholine receptor; cytoplasmic loops; desensitization; patch clamp; single channel
In China, mesangial proliferative glomerulonephritis (MsPGN) is one of the most common kidney diseases. In this study, we treated a rat model of chronic anti-Thy-1 MsPGN with Shenhua Tablet and evaluated whether the tablet was able to protect the kidney function. Thirty-six Wistar rats were randomly divided into six groups: (1) Sham surgery (Sham); (2) anti-Thy-1 nephritis model (Thy-1); (3) anti-Thy-1 nephritis model + irbesartan-treated (Irb); (4) anti-Thy-1 nephritis model + low-dose of Shenhua Tablet (SHL); (5) anti-Thy-1 nephritis model + medium-dose of Shenhua Tablet (SHM); (6) anti-Thy-1 nephritis model + high-dose of Shenhua Tablet (SHH).
Thirteen weeks after drug treatment, urinary proteins were quantified and renal pathological changes were thoroughly examined at the time point of 24 h. Meanwhile, the expression levels of p-Erk1/2, cyclin D1 and p21 at the renal cortex were also tested. The levels of urinary proteins and total cholesterol in the blood were significantly reduced in rats treated with any drug tested in this study. The level of triglyceride was significantly reduced in all three Shenhua Tablet-treated groups. Renal pathomorphological scores were significantly improved in groups of Irb, SHM and SHH. Mesangial cell proliferation was significantly inhibited in any drug-treated group. p-Erk1/2 and cyclin D1 were downregulated whereas p21 was upregulated in the renal cortex.
Our study indicated that Shenhua Tablet is able to inhibit the abnormal proliferation of mesangial cells and to prevent kidney damage, which is likely associated with downregulation of p-Erk1/2 and reduced activity of its downstream target-cyclin D1.
Shenhua Tablet; Chronic anti-Thy-1 glomerulonephritis; Mesangial cell proliferation; Erk
Magnetotactic bacteria (MTB), a group of phylogenetically diverse organisms that use their unique intracellular magnetosome organelles to swim along the Earth’s magnetic field, play important roles in the biogeochemical cycles of iron and sulfur. Previous studies have revealed that the bacterial actin protein MamK plays essential roles in the linear arrangement of magnetosomes in MTB cells belonging to the Proteobacteria phylum. However, the molecular mechanisms of multiple-magnetosome-chain arrangements in MTB remain largely unknown. Here, we report that the MamK filaments from the uncultivated ‘Candidatus Magnetobacterium casensis’ (Mcas) within the phylum Nitrospirae polymerized in the presence of ATP alone and were stable without obvious ATP hydrolysis-mediated disassembly. MamK in Mcas can convert NTP to NDP and NDP to NMP, showing the highest preference to ATP. Unlike its Magnetospirillum counterparts, which form a single magnetosome chain, or other bacterial actins such as MreB and ParM, the polymerized MamK from Mcas is independent of metal ions and nucleotides except for ATP, and is assembled into well-ordered filamentous bundles consisted of multiple filaments. Our results suggest a dynamically stable assembly of MamK from the uncultivated Nitrospirae MTB that synthesizes multiple magnetosome chains per cell. These findings further improve the current knowledge of biomineralization and organelle biogenesis in prokaryotic systems.
Electronic supplementary material
The online version of this article (doi:10.1007/s13238-016-0253-x) contains supplementary material, which is available to authorized users.
magnetotactic bacteria; Nitrospirae; bacterial actin; MamK; assembly mechanism
Influenza A virus (IAV) is a severe worldwide threat to public health and economic development that results in the emergence of drug-resistant or highly virulent strains. Therefore, it is imperative to develop potent anti-IAV drugs with different modes of action to currently available drugs. Herein, we show a new class of antiviral peptides generated by conjugating two known short antiviral peptides: part-1 (named Jp with the sequence of ARLPR) and part-2 (named Hp with the sequence of KKWK). The new peptides were thus created by hybridization of these two domains at C- and N- termini, respectively. The anti-IAV screening results identified that C20-Jp-Hp was the most potent peptide with IC50 value of 0.53 μM against A/Puerto Rico/8/34 (H1N1) strain. Interestingly, these new peptides display lower toxicities toward mammalian cells and higher therapeutic indices than their prototypes. In addition, the mechanism of action of C20-Jp-Hp was extensively investigated.
Oral decoctions of traditional Chinese medicines (TCMs) serve for therapeutic and prophylactic management of diseases for centuries. Small molecules and polysaccharides are the dominant chemicals co-occurred in the TCM decoction. Small molecules are well-studied by multidisciplinary elaborations, whereas the role of polysaccharides remains largely elusive. Here we explore a gut microbiota-involved mechanism by which TCM polysaccharides restore the homeostasis of gut microbiota and consequently promote the systemic exposure of concomitant small molecules in the decoction. As a case study, ginseng polysaccharides and ginsenosides in Du-Shen-Tang, the decoction of ginseng, were investigated on an over-fatigue and acute cold stress model. The results indicated that ginseng polysaccharides improved intestinal metabolism and absorption of certain ginsenosides, meanwhile reinstated the perturbed holistic gut microbiota, and particularly enhanced the growth of Lactobacillus spp. and Bacteroides spp., two major metabolic bacteria of ginsenosides. By exploring the synergistic actions of polysaccharides with small molecules, these findings shed new light on scientization and rationalization of the classic TCM decoctions in human health care.
We propose a coupled mathematical modelling system to investigate glioblastoma growth in response to dynamic changes in chemical and haemodynamic microenvironments caused by pre-existing vessel co-option, remodelling, collapse and angiogenesis. A typical tree-like architecture network with different orders for vessel diameter is designed to model pre-existing vasculature in host tissue. The chemical substances including oxygen, vascular endothelial growth factor, extra-cellular matrix and matrix degradation enzymes are calculated based on the haemodynamic environment which is obtained by coupled modelling of intravascular blood flow with interstitial fluid flow. The haemodynamic changes, including vessel diameter and permeability, are introduced to reflect a series of pathological characteristics of abnormal tumour vessels including vessel dilation, leakage, angiogenesis, regression and collapse. Migrating cells are included as a new phenotype to describe the migration behaviour of malignant tumour cells. The simulation focuses on the avascular phase of tumour development and stops at an early phase of angiogenesis. The model is able to demonstrate the main features of glioblastoma growth in this phase such as the formation of pseudopalisades, cell migration along the host vessels, the pre-existing vasculature co-option, angiogenesis and remodelling. The model also enables us to examine the influence of initial conditions and local environment on the early phase of glioblastoma growth.
Chylothorax is the accumulation of lymph fluid in the pleura. Gastric carcinoma with chylothorax and lymphedema as the initial manifestations has rarely been reported, with only 14 cases reported to date. The mechanisms of gastric carcinoma generating chylothorax have not yet been determined. The current study reports the case of a 63-year-old woman presenting with chylothorax and lower extremity lymphedema, and reviews the existing literature. A chest radiograph performed on the present patient revealed large pleural effusion and chylothorax was diagnosed. Upper gastrointestinal endoscopy identified an irregular apophysis lesion and a biopsy confirmed poorly differentiated gastric adenocarcinoma. The patient was discharged at her request, and subsequently succumbed to the disease 4.5 months later. Based on the findings of the present study, as well as those of the literature, we proposed a novel form of gastric carcinoma infiltrating the body. Chylothorax and lymphedema may be a consequence of gastric carcinoma cells infiltrating the lymphatic circulatory system; therefore, the differential diagnosis of chylothorax and lymphedema of unknown cause should consider gastric carcinoma, regardless of gastrointestinal symptoms.
gastric carcinoma; chylothorax; lymphedema; pleural effusion
Recently, the significant microsaccade-induced neural responses have been extensively observed in experiments. To explore the underlying mechanisms of the observed neural responses, a feedforward network model with short-term synaptic depression has been proposed [Yuan, W.-J., Dimigen, O., Sommer, W. and Zhou, C. Front. Comput. Neurosci. 7, 47 (2013)]. The depression model not only gave an explanation for microsaccades in counteracting visual fading, but also successfully reproduced several microsaccade-related features in experimental findings. These results strongly suggest that, the depression model is very useful to investigate microsaccade-related neural responses. In this paper, by using the model, we extensively study and predict the dependance of microsaccade-related neural responses on several key parameters, which could be tuned in experiments. Particularly, we provide a significant prediction that microsaccade-related neural response also complies with the property “sharper is better” observed in many contexts in neuroscience. Importantly, the property exhibits a power-law relationship between the width of input signal and the responsive effectiveness, which is robust against many parameters in the model. By using mean field theory, we analytically investigate the robust power-law property. Our predictions would give theoretical guidance for further experimental investigations of the functional role of microsaccades in visual information processing.
Since early 2013, H7N9-subtype avian influenza virus (AIV) has caused human infection in eastern China. To evaluate AIV contamination and the public risk of infection, we systematically implemented environmental sampling from live poultry markets in Guangdong Province. Through real-time polymerase chain reaction assays and next-generation sequencing, we generated full nucleotide sequences of all 10 H6N6 AIVs isolated during sampling. Focusing on sequence analyses of hemagglutinin genes of the 10 H6N6 AIVs revealed that the viruses were low pathogenic AIVs with the typical hemagglutinin cleavage site of P-Q-I-E-T-R-G. The hemagglutinin, neuraminidase, and nucleocapsid genes of nine AIVs were of ST2853-like (H6-subtype) lineage, ST192-like (N6-subtype) lineage, and HN573-like (H6-subtype) lineage, respectively; whereas the other five genes were of ST339-like (H6-subtype) lineage. However, the polymerase PB2 and nucleocapsid genes of one strain (HZ057) were of GS/GD-like (H5N1-subtype) and ST339-like lineages. Phylogenic analysis revealed that all eight genes of the 10 viruses belonged to Eurasian avian lineage. Altogether, the 10 AIVs were reassortants of different genetic groups of exchanges with the same virus subtype, thus illustrating the genetic diversity and complexity of H6N6-subtype AIVs in Guangdong Province.
avian influenza virus; H6N6; live poultry market; reassortment; Guangdong
Human hypothalamic hamartoma (HH) is a rare developmental malformation
often characterized by gelastic seizures, which are refractory to medical
therapy. Ictal EEG recordings from the HH have demonstrated that the epileptic
source of gelastic seizures lies within the HH lesion itself. Recent advances in
surgical techniques targeting HH have led to dramatic improvements in seizure
control, which further supports the hypothesis that gelastic seizures originate
within the HH. However, the basic cellular and molecular mechanisms of
epileptogenesis in this subcortical lesion are poorly understood. Since 2003,
Barrow Neurological Institute has maintained a multidisciplinary clinical
program to evaluate and treat patients with HH. This program has provided a
unique opportunity to investigate the basic mechanisms of epileptogenesis using
surgically resected HH tissue. The first report on the electrophysiological
properties of HH neurons was published in 2005. Since then, ongoing research has
provided additional insights into the mechanisms by which HH generate seizure
activity. In this review, we summarize this progress and propose a cellular
model that suggests that GABA-mediated excitation contributes to epileptogenesis
in HH lesions.
Human hypothalamic hamartoma; gelastic seizures; epileptogenesis
Head and neck squamous cell carcinoma (HNSCC) development is a multistage process includes the normal, dysplasia and squamous cell carcinoma (SCC) stages. Recently, increasing evidence has suggested that the tumor microenvironment (TME) is an integral part of malignant transformation. Exploring certain key node genes in TME for future intervention in dysplasia to interrupt oral carcinogenesis was the primary goal of this research. To achieve this goal, systems biology approaches were first applied to the epithelia and fibroblasts collected at sequential stages in a 4-nitroquinoline-1-oxide (4NQO) - induced rat oral carcinogenesis model. Through bioinformatics network construction, IL-1β was identified as one of the key node genes in TME during carcinogenesis. Immunohistochemical staining of human and rat samples demonstrated that IL-1β expression patterns were parallel to the stages of malignant transformation. Silencing IL-1β with lentivirus-delivered shRNA significantly inhibited oral squamous cell carcinoma cell growth both in vivo and in vitro. Based on these findings, we hypothesized that IL-1β may be a chemoprevention target in TME during oral carcinogenesis. Therefore, we targeted IL-1 in the TME by oral mucosal injection of an IL-1 receptor antagonist in 4NQO rats. The results demonstrated that targeting IL-1 could interrupt oral carcinogenesis by reprogramming the TME.
Mycobacterium tuberculosis (MTB) Beijing strains have caused a great concern because of their rapid emergence and increasing prevalence in worldwide regions. Great efforts have been made to investigate the pathogenic characteristics of Beijing strains such as hypervirulence, drug resistance and favoring transmission. Phylogenetically, MTB Beijing family was divided into modern and ancient sublineages. Modern Beijing strains displayed enhanced virulence and higher prevalence when compared with ancient Beijing strains, but the genetic basis for this difference remains unclear. In this study, by analyzing previously published sequencing data of 1082 MTB Beijing isolates, we determined the genetic changes that were commonly present in modern Beijing strains but absent in ancient Beijing strains. These changes include 44 single-nucleotide polymorphisms (SNPs) and two short genomic deletions. Through bioinformatics analysis, we demonstrated that these genetic changes had high probability of functional effects. For example, 4 genes were frameshifted due to premature stop mutation or genomic deletions, 19 nonsynonymous SNPs located in conservative codons, and there is a significant enrichment in regulatory network for all nonsynonymous mutations. Besides, three SNPs located in promoter regions were verified to alter downstream gene expressions. Our study precisely defined the genetic features of modern Beijing strains and provided interesting clues for future researches to elucidate the mechanisms that underlie this sublineage's successful expansion. These findings from the analysis of the modern Beijing sublineage could provide us a model to understand the dynamics of pathogenicity of MTB.
ancient sublineage; Beijing family; microevolution; modern sublineage; Mycobacterium tuberculosis
Stroke is the third leading cause of death in industrialized nations. Oxidative stress is involved in the pathogenesis of stroke, and excessive generation of reactive oxygen species (ROS) by mitochondria is thought to be the main cause of oxidative stress. NADPH oxidase (NOX) enzymes have recently been identified and studied as important producers of ROS in brain tissues after stroke. Several reports have shown that knockout or deletion of NOX exerts a neuroprotective effect in three major experimental stroke models. Recent studies also confirmed that NOX inhibitors ameliorate brain injury and improve neurological outcome after stroke. However, the physiological and pathophysiological roles of NOX enzymes in the central nervous system (CNS) are not known well. In this review, we provide a comprehensive summary of our current understanding about expression and physiological function of NOX enzymes in the CNS and its pathophysiological roles in the three major types of stroke: ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage.
Previous studies have investigated that the expression levels of MALAT-1 were higher in cancerous tissues than matched histologically normal tissues. And, to some extent, overexpression of MALAT-1 was inclined to lymph node metastasis. This meta-analysis collected all relevant articles and explored the association between MALAT-1 expression levels and lymph node metastasis. We searched PubMed, EmBase, Web of Science, Cochrane Library, and OVID to address the level of MALAT-1 expression in cancer cases and noncancerous controls (accessed February 2015). And 8 studies comprising 696 multiple cancer patients were included to assess this association. The odds ratio (OR) and its corresponding 95% confidence interval (CI) were calculated to assess the strength of the association using Stata 12.0 version software. The results revealed there was a significant difference in the incidence of lymph node metastasis between high MALAT-1 expression group and low MALAT-1 expression group (OR = 1.94, 95% CI 1.15–3.28, P = 0.013 random-effects model). Subgroup analysis indicated that MALAT-1 high expression had an unfavorable impact on lymph node metastasis in Chinese patients (OR = 1.87, 95% CI 1.01–2.46). This study demonstrated that the incidence of lymph node metastasis in patients detected with high MALAT-1 expression was higher than that in patients with low MALAT-1 expression in China.
Flavones are important secondary metabolites found in many plants. In Lonicera species, flavones contribute both physiological and pharmaceutical properties. However, flavone synthase (FNS), the key enzyme responsible for flavone biosynthesis, has not yet been characterized in Lonicera species. In this study, FNSII genes were identified from Lonicera japonica Thunb. and L. macranthoides Hand.-Mazz. In the presence of NADPH, the recombinant cytochrome P450 proteins encoded by LjFNSII-1.1, LjFNSII-2.1, and LmFNSII-1.1 converted eriodictyol, naringenin, and liquiritigenin to the corresponding flavones directly. The different catalytic properties between LjFNSII-2.1 and LjFNSII-1.1 were caused by a single amino acid substitution at position 242 (glutamic acid to lysine). A methionine at position 206 and a leucine at position 381 contributed considerably to the high catalytic activity of LjFNSII-1.1. In addition, LjFNSII-1.1&2.1 and LmFNSII-1.1 also biosynthesize flavones that were further modified by O-glycosylation in transgenic tobacco. The expression levels of the FNSII genes were consistent with flavone accumulation patterns in flower buds. Our findings suggested that the weak catalytic activity of LmFNSII-1.1 and the relatively low expression of LmFNSII-1.1 in flowers might be responsible for the low levels of flavone accumulation in flower buds of L. macranthoides.
There are sparse and limited studies on erythrocyte morphology in renal biopsy identifying nephropathic patients among type 2 diabetics. The present study sought to clarify the predictive value of dysmorphic erythrocytes in type 2 diabetics with non‐diabetic renal disease and influences on hematuria.
Materials and Methods
We examined 198 patients with type 2 diabetes who underwent kidney biopsies between 2012 and 2013. Hematuria was defined as >3 or >10 red blood cells per high‐power field (RBCs/hpf) in urine sediment. If >80% of the erythrocytes were dysmorphic, glomerular hematuria was diagnosed. Clinical findings and predictive value of dysmorphic erythrocytes were compared between patients with hematuria (n = 19) and those without (n = 61). The potential risk factors for hematuria among diabetic nephropathy patients were also screened.
There was a statistically significant difference between the diabetic nephropathy group and the non‐diabetic renal disease group (6.6 vs 16.8%; P = 0.04) when the demarcation point of hematuria was 10 RBCs/hpf. When the definition of hematuria was based on an examination of urinary erythrocyte morphology, a marked difference was seen (3.3 vs 24.8%; P < 0.001). Glomerular hematuria showed high specificity and a positive predictive value (0.97 and 0.94, respectively) in non‐diabetic renal disease. A multivariate analysis showed that nephrotic syndrome was significantly associated with hematuria (odds ratio 3.636; P = 0.034).
Dysmorphic erythrocytes were superior to hematuria for indicating non‐diabetic renal disease in type 2 diabetics. Nephrotic syndrome was an independent risk factor for hematuria.
Hematuria; Nephropathy; Type 2 diabetics
The haemoflagellate Trypanosoma lewisi is a kinetoplastid parasite which, as it has been recently reported to cause human disease, deserves increased attention. Characteristic features of all kinetoplastid flagellates are a uniquely structured mitochondrial DNA or kinetoplast, comprised of a network of catenated DNA circles, and RNA editing of mitochondrial transcripts. The aim of this study was to describe the kinetoplast DNA of T. lewisi.
In this study, purified kinetoplast DNA from T. lewisi was sequenced using high-throughput sequencing in combination with sequencing of PCR amplicons. This allowed the assembly of the T. lewisi kinetoplast maxicircle DNA, which is a homologue of the mitochondrial genome in other eukaryotes. The assembly of 23,745 bp comprises the non-coding and coding regions. Comparative analysis of the maxicircle sequence of T. lewisi with Trypanosoma cruzi, Trypanosoma rangeli, Trypanosoma brucei and Leishmania tarentolae revealed that it shares 78 %, 77 %, 74 % and 66 % sequence identity with these parasites, respectively. The high GC content in at least 9 maxicircle genes of T. lewisi (ATPase6; NADH dehydrogenase subunits ND3, ND7, ND8 and ND9; G-rich regions GR3 and GR4; cytochrome oxidase subunit COIII and ribosomal protein RPS12) implies that their products may be extensively edited. A detailed analysis of the non-coding region revealed that it contains numerous repeat motifs and palindromes.
We have sequenced and comprehensively annotated the kinetoplast maxicircle of T. lewisi. Our analysis reveals that T. lewisi is closely related to T. cruzi and T. brucei, and may share similar RNA editing patterns with them rather than with L. tarentolae. These findings provide novel insight into the biological features of this emerging human pathogen.
Electronic supplementary material
The online version of this article (doi:10.1186/s13071-015-1281-8) contains supplementary material, which is available to authorized users.
Trypanosoma lewisi; Kinetoplast maxicircle; Mitochondrial DNA; RNA editing; Palindrome
The tumor suppressor gene CDH1 is critical for intercellular adhesion. In our previous work, we reported a nonfunctional CDH1 transcript that lacks the final 83 base pairs of exon 8 (1054del83). In this work, we probed the role of histone epigenetic modifications as well as DNA methylation in selection of this isoform.
RT-qPCR was used to detect CDH1 RNA expression. Methylation of CDH1 was analyzed by bisulphite sequencing PCR. ChIP assay was performed to show histones level. Cell lines were treated with DNA methyltransferase inhibitor AZA, HDAC inhibitor TSA, or siRNA oligonucleotides to test regulation of CDH1 splicing.
Greater CDH1 1054del83 transcripts were observed in gastric cancer (GC) cell lines than human gastric mucosal epithelial cell line GES-1. All the cell lines showed significant methylation pattern at the CpG sites of CDH1 exon 8. AZA treatment did not influence selection of 1054del83 transcripts. A significant decrease in acetylation for histones H3 and H4K16Ac in an internal region of the CDH1 gene surrounding the alternative exon 8 were detected in GC cell lines. Treatment with TSA preferentially expressed the correctly spliced transcript and not the exon 8 skipped aberrant transcripts, showing that histone acetylation was involved in the splicing regulation. SiRNA-mediated knockdown of SETD2 (The specific methyltransferase of H3K36) decreased exclusion of exon 8, suggesting that the presence of this mark correlates with increased skipping of the final 83 base pairs of CDH1 exon 8. However, CDH1 splicing was not affected by SRSF2 knockdown.
H3K36me3 correlates with increased skipping of the final 83 base pairs of CDH1 exon 8. Histone acetylation was involved in the splicing regulation as well.
Electronic supplementary material
The online version of this article (doi:10.1186/s12885-015-1983-5) contains supplementary material, which is available to authorized users.
Alternative splicing; CDH1; Histone modifications; DNA methylation; Gastric cancer
Cyclophosphamide (CP), a chemotherapeutic agent, is restricted due to its side effects, especially hepatotoxicity. Ginseng has often been clinically used with CP in China, but whether and how ginseng reduces the hepatotoxicity is unknown. In this study, the hepatoprotective effects and mechanisms under the combined usage were investigated. It was found that ginseng could ameliorate CP-induced elevations of ALP, ALT, ALS, MDA and hepatic deterioration, enhance antioxidant enzymes’ activities and GSH’s level. Metabolomics study revealed that 33 endogenous metabolites were changed by CP, 19 of which were reversed when ginseng was co-administrated via two main pathways, i.e., GSH metabolism and primary bile acids synthesis. Furthermore, ginseng could induce expression of GCLC, GCLM, GS and GST, which associate with the disposition of GSH, and expression of FXR, CYP7A1, NTCP and MRP 3, which play important roles in the synthesis and transport of bile acids. In addition, NRF 2, one of regulatory elements on the expression of GCLC, GCLM, GS, GST, NTCP and MRP3, was up-regulated when ginseng was co-administrated. In conclusion, ginseng could alleviate CP-induced hepatotoxicity via modulating the disordered homeostasis of GSH and bile acid, which might be mediated by inducing the expression of NRF 2 in liver.
Levels of the cyclooxygenase 2 (COX-2) enzyme are elevated in breast cancer tissue, and most COX-2 effects are believed to be mediated through overproduction of prostaglandin-E2 (PGE2). We evaluated associations between the primary urinary metabolite of PGE2 (PGE-M) and breast cancer risk.
A nested case-control study of 504 cases and 1,082 controls was conducted using data from the Shanghai Women’s Health Study, a large population-based prospective cohort study of 74,941 Chinese women. Urinary PGE-M was measured using a liquid chromatography/tandem mass spectrometric method. Logistic regression estimated odds ratios (OR) and 95% confidence intervals (95%CI), with adjustment for potential confounders.
Overall, no association between urinary PGE-M and breast cancer was detected. However, a suggestive positive association was found among postmenopausal women. In particular, a clear dose-response relationship between urinary PGE-M and breast cancer was observed among postmenopausal women with a BMI<25 kg/m2 (P for linear trend = 0.005). Among these women, risk of breast cancer increased from 1.00 (reference) to 1.06 (95% CI: 0.56–1.99), 1.50 (95% CI: 0.79–2.83), and 2.32 (95% CI: 1.24–4.41) for the lowest to highest quartiles of PGE-M, and such associations were stronger among those who were diagnosed with cancer within the first 4 years of sample collection. No apparent association was observed among overweight postmenopausal women (BMI≥25 kg/m2).
High urinary PGE-M level was associated with elevated risk of breast cancer among normal weight, postmenopausal women.
Urinary PGE-M level may be useful for breast cancer risk assessment among normal weight, postmenopausal women.
breast cancer; prostaglandin E2 metabolite; biomarker; postmenopausal Chinese women; body mass index
Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant inherited disease characterized by gastrointestinal hamartomatous polyps and mucocutaneous melanin spots. Germline mutation of the serine/threonine kinase 11 (STK11) gene are responsible for PJS. In this study, we investigated the clinical characteristics and molecular basis of the disease in Chinese children with PJS.
Thirteen children diagnosed with PJS in our hospital were enrolled in this study from 2011 to 2015, and their clinical data on polyp characteristics, intussusceptions events, family histories, etc. were described. Genomic DNA was extracted from whole-blood samples from each subject, and the entire coding sequence of the STK11 gene was amplified by polymerase chain reaction and analyzed by direct sequencing.
The median age at the onset of symptoms was 2 years and 4 months. To date, these children have undergone 40 endoscopy screenings, 17 laparotomies and 9 intussusceptions. Polyps were found in the stomach, duodenum, small bowel, colon and rectum, with large polyps found in 7 children. Mutations were found in eleven children, including seven novel mutations (c.481het_dupA, c.943_944het_delCCinsG, c.397het_delG, c.862 + 1G > G/A, c.348_349het_delGT, and c.803_804het_delGGinsC and c.121_139de l19insTT) and four previously reported mutations (c.658C > C/T, c.890G > G/A, c.1062 C > C/G, and c.290 + 1G > G/A). One PJS patient did not have any STK11 mutations.
The polyps caused significant clinical consequences in children with PJS, and mutations of the STK11 gene are generally the cause of PJS in Chinese children. This study expands the spectrum of known STK11 gene mutations.
Peutz-Jeghers syndrome; STK11 gene; Mutation; Mucocutaneous pigmentation; Chinese children
Small non-coding RNAs (e.g. miRNAs) and long non-coding RNAs (e.g. lincRNAs and circRNAs) are emerging as key regulators of various cellular processes. However, only a very small fraction of these enigmatic RNAs have been well functionally characterized. In this study, we describe deepBase v2.0 (http://biocenter.sysu.edu.cn/deepBase/), an updated platform, to decode evolution, expression patterns and functions of diverse ncRNAs across 19 species. deepBase v2.0 has been updated to provide the most comprehensive collection of ncRNA-derived small RNAs generated from 588 sRNA-Seq datasets. Moreover, we developed a pipeline named lncSeeker to identify 176 680 high-confidence lncRNAs from 14 species. Temporal and spatial expression patterns of various ncRNAs were profiled. We identified approximately 24 280 primate-specific, 5193 rodent-specific lncRNAs, and 55 highly conserved lncRNA orthologs between human and zebrafish. We annotated 14 867 human circRNAs, 1260 of which are orthologous to mouse circRNAs. By combining expression profiles and functional genomic annotations, we developed lncFunction web-server to predict the function of lncRNAs based on protein-lncRNA co-expression networks. This study is expected to provide considerable resources to facilitate future experimental studies and to uncover ncRNA functions.