Generation of genomic-integration-free human induced pluripotent stem cells and the derived cardiomyocytes of X-linked dilated cardiomyopathy from DMD gene mutation

We derived an integration-free induced pluripotent stem cell (iPSC) line from the peripheral blood mononuclear cells (PBMCs) of a 23-year-old male patient. This patient carries a 5' splice site point mutation in intron 1 (c.31+1G>A) of the dystrophin gene, a mutation associated with X-linked dilated cardiomyopathy (XLDCM). Sendai virus was used to reprogram the PBMCs and deliver OCT3/4, SOX2, c-MYC, and KLF4 factors. The iPSC line (HKUi002-A) generated preserved the mutation, expressed common pluripotency markers, differentiated into three germ layers in vivo, and exhibited a normal karyotype. Further differentiation into cardiomyocytes enables the study of the disease mechanisms of XLDCM.

Satisfaction, preference and error occurrence of three dry powder inhalers as assessed by a cohort naïve to inhaler operation

Background

Inhaled medication is central to the treatment of COPD. Various types of inhaler devices, which directly deliver medication to the lung, have been developed. However, patients often exhibit incorrect techniques of inhaler usage. Effectiveness of therapy may be affected by the ease of device usage, size, convenience of use, durability, clarity of instructions and device preferences of patients. This study compares the satisfaction and preference, as well as error occurrence, with the use of Genuair^®, Ellipta™ and Breezhaler™ by healthy subjects in Hong Kong.

Subjects and methods

One hundred and thirty healthy Hong Kong Chinese subjects aged ≥40 years without a previous diagnosis of COPD and asthma and with no experience of using dry powder inhalers (DPIs) were recruited. Subjects learned to use the three DPIs by initially reading the instructions and then observing a demonstration with verbal explanation. The number of errors committed was evaluated. Subjects also completed a questionnaire to indicate their satisfaction and preference.

Results

The satisfaction score of comfort for Breezhaler was significantly higher than that for Ellipta (p≤0.05), while the satisfaction score on confidence to have inhaled the entire dose was highest for Genuair compared with Ellipta (p≤0.0001) or Breezhaler (p≤0.05). The overall satisfaction score was significantly higher for Genuair than Ellipta (p≤0.05) or Breezhaler (p≤0.01). After reading the instructions, the highest number of subjects committing one or more critical errors was with Breezhaler (97) followed by Genuair (70) and then Ellipta (33). Demonstration reduced the number of critical errors made by subjects for each DPI to one third or lower.

Conclusion

Breezhaler seemed to be more comfortable and easy to carry, but users made less critical errors when using Ellipta after reading the instructions only. Genuair provided the clearest indication of correct dose preparation and inhalation.

Identification of a novel distal regulatory element of the human Neuroglobin gene by the chromosome conformation capture approach

Neuroglobin (NGB) is predominantly expressed in the brain and retina. Studies suggest that NGB exerts protective effects to neuronal cells and is implicated in reducing the severity of stroke and Alzheimer's disease. However, little is known about the mechanisms which regulate the cell type-specific expression of the gene. In this study, we hypothesized that distal regulatory elements (DREs) are involved in optimal expression of the NGB gene. By chromosome conformation capture we identified two novel DREs located -70 kb upstream and +100 kb downstream from the NGB gene. ENCODE database showed the presence of DNaseI hypersensitive and transcription factors binding sites in these regions. Further analyses using luciferase reporters and chromatin immunoprecipitation suggested that the -70 kb region upstream of the NGB gene contained a neuronal-specific enhancer and GATA transcription factor binding sites. Knockdown of GATA-2 caused NGB expression to drop dramatically, indicating GATA-2 as an essential transcription factor for the activation of NGB expression. The crucial role of the DRE in NGB expression activation was further confirmed by the drop in NGB level after CRISPR-mediated deletion of the DRE. Taken together, we show that the NGB gene is regulated by a cell type-specific loop formed between its promoter and the novel DRE.

Preference of Food Saltiness and Willingness to Consume Low-Sodium Content Food in a Chinese Population

OBJECTIVE

To compare the preference of food saltiness and the willingness to consume low-sodium food among hypertensive older people, non-hypertensive older people and non-hypertensive young people in a Chinese population.

DESIGN

A cross-sectional study based on a quota sample. Three saltiness options (low-sodium, medium-sodium and high-sodium) of soup and bread were offered to each participant who rated the taste of each food on a 5-point Likert scale. Then, the participants rated their willingness to consume the low-sodium content foods on a 5-point Likert scale, given they were informed of the benefit of the low-sodium option. Generalised linear mixed model and multiple linear regression were used to analyse the data.

SETTING

Elderly centres and community centres in Hong Kong.

PARTICIPANTS

Sixty hypertensive older people, 49 non-hypertensive older people and 60 non-hypertensive young people were recruited from June to August 2014.

MEASUREMENTS

The tastiness score and the willingness score were the primary outcome measures. The Chinese Health Literacy Scale for Low Salt Consumption - Hong Kong population (CHLSalt-HK) was also assessed.

RESULTS

The tastiness rating of the high-sodium option of soup was significantly lower than the medium-sodium option (p<0.001), but there was no significant difference between the low-sodium and the medium-sodium options (p=0.204). For bread, tastiness rating of the low-sodium option and the high-sodium option were significantly lower than the medium-sodium option (p<0.001 for both options). The tastiness score of soup did not have significant difference across the groups (p=0.181), but that of bread from the hypertensive older adults (p=0.012) and the non-hypertensive older adults (p=0.006) was significantly higher than the non-hypertensive young adults. Higher willingness rating to consume the low-sodium option was significantly (p<0.001) associated with higher tastiness rating of the low-sodium option of soup and bread, and weakly associated with higher health literacy of low salt intake (soup: p=0.041; bread: p=0.024). Hypertensive older adults tended to be more willing to consume the low-sodium option than non-hypertensive older adults for soup (p=0.009), there was insignificant difference between non-hypertensive older adults and non-hypertensive young adults (p=0.156). For bread, there was insignificant difference in willingness rating to consume low-sodium option (p=0.375).

CONCLUSION

Older people are at a higher risk of hypertension, reduction of salt intake is important for them to reduce their risk of cardiovascular diseases. There is room for reducing the sodium content of soup, while the sodium in bread should be reduced progressively. Improving the taste of low-sodium food may help to promote reduction in dietary sodium intake.

The novel thiosemicarbazone, di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC), inhibits neuroblastoma growth in vitro and in vivo via multiple mechanisms

Background

Neuroblastoma is a relatively common and highly belligerent childhood tumor with poor prognosis by current therapeutic approaches. A novel anti-cancer agent of the di-2-pyridylketone thiosemicarbazone series, namely di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT), demonstrates promising anti-tumor activity. Recently, a second-generation analogue, namely di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC), has entered multi-center clinical trials for the treatment of advanced and resistant tumors. The current aim was to examine if these novel agents were effective against aggressive neuroblastoma in vitro and in vivo and to assess their mechanism of action.

Methods

Neuroblastoma cancer cells as well as immortalized normal cells were used to assess the efficacy and selectivity of DpC in vitro. An orthotopic SK-N-LP/Luciferase xenograft model was used in nude mice to assess the efficacy of DpC in vivo. Apoptosis in tumors was confirmed by Annexin V/PI flow cytometry and H&E staining.

Results

DpC demonstrated more potent cytotoxicity than Dp44mT against neuroblastoma cells in a dose- and time-dependent manner. DpC significantly increased levels of phosphorylated JNK, neuroglobin, cytoglobin, and cleaved caspase 3 and 9, while decreasing IkBα levels in vitro. The contribution of JNK, NF-ĸB, and caspase signaling/activity to the anti-tumor activity of DpC was verified by selective inhibitors of these pathways. After 3 weeks of treatment, tumor growth in mice was significantly (p < 0.05) reduced by DpC (4 mg/kg/day) given intravenously and the agent was well tolerated. Xenograft tissues showed significantly higher expression of neuroglobin, cytoglobin, caspase 3, and tumor necrosis factor-α (TNFα) levels and a slight decrease in interleukin-10 (IL-10).

Conclusions

DpC was found to be highly potent against neuroblastoma, demonstrating its potential as a novel therapeutic for this disease. The ability of DpC to increase TNFα in tumors could also promote the endogenous immune response to mediate enhanced cancer cell apoptosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13045-016-0330-x) contains supplementary material, which is available to authorized users.

The cell cycle effects of docosahexaenoic acid on human metastatic hepatocellular carcinoma proliferation

Given the reported side effects associated with chemotherapy and surgical resection, dietary intervention with omega-3 polyunsaturated fatty acids (PUFAs) has been postulated to be an alterative way to prevent liver cancer progression and metastasis. We studied the effects of an omega-3 PUFA, docahexaenoic acid (DHA) on COX-2 expression and the cell cycle control machinery that co-ordinately regulate the HCC cells growth. Our data showed that DHA (0-200 microM) retarded proliferation of the human metastatic HCC cell line MHCC97L dose-dependently. In addition, inhibition of cyclin A/Cdk2 interfered with S-phase progression further in agreement with the result of bivariate flow cytometric analysis which indicated that DNA synthesis time (Ts) was significantly prolonged by DHA in MHCC97L. The N-myc oncogene, the heat shock proteins Hsp27 and glucose-related protein 78 (GRP78) as well as the antioxidant enzymes superoxide dismutase may play significant roles in the cell cycle control and reduced-proliferation of MHCC97L by DHA. Our data indicated that it is imperative to develop therapeutic strategy with omega-3 PUFA that simultaneously targets COX-2 and other cell cycle regulators in hepatocarcinogenesis. This study provides novel mechanistic insights into the modulation of DHA on human hepatocarcinoma.

Localization and expression pattern of cytoglobin in carbon tetrachloride-induced liver fibrosis

Cytoglobin (Cygb) is a recently discovered hexacoordinate globin protein with a yet undefined function. It was found to be up-regulated in toxin-induced liver fibrosis and during hypoxic conditions [Fago, A., Hundahl, C., Malte, H., Weber, R.E., 2004. Functional properties of neuroglobin and cytoglobin. Insights into the ancestral physiological roles of globins. IUBMB Life 56, 689-696; Fordel, E., Thijs, L., Martinet, W., Schrijvers, D., Moens, L., Dewilde, S., 2007. Anoxia or oxygen and glucose deprivation in SH-SY5Y cells: a step closer to the unraveling of neuroglobin and cytoglobin functions. Gene 398, 114-122; Guo, X., Philipsen, S., Tan-Un, K.C., 2007. Study of the hypoxia-dependent regulation of human CYGB gene. Biochem. Biophys. Res. Commun. 364, 145-150; Li, D., Chen, X.Q., Li, W.J., Yang, Y.H., Wang, J.Z., Yu, A.C., 2007. Cytoglobin up-regulated by hydrogen peroxide plays a protective role in oxidative stress. Neurochem. Res. 32, 1375-1380]. Cygb is expressed ubiquitously in most tissues but its subcellular localization in certain cell types (e.g. hepatocytes) is still controversial. In this study we investigated the localization of Cygb protein in mouse tissues, its expression pattern in response to carbon tetrachloride (CCl(4)) challenge and that during CCl(4)-induced liver fibrosis in order to delineate the functional property of Cygb. We found that it is expressed in fibroblasts in various organs and in the hepatic stellate cells. Cygb mRNA expression is up-regulated by more than 3.5-fold 24h after administration of CCl(4). At 48h post-administration, the expression of procollagen I alpha 1 mRNA was increased by over 7.6-fold. The increase in collagen expression after CCl(4) insult was also evident at the protein level. We found that the number of Cygb-expressing cells increased through the development of CCl(4)-induced liver fibrosis. It may be possible that Cygb is an early biomarker for liver fibrosis.

The study of sequence configuration and functional impact of the (AC)n(AT)xTy motif in human beta-globin gene promoter

In this report we examine the (AC)n(AT)xTy motif residing -530 bp 5' upstream of the beta-globin gene in Chinese thalassaemic patients. This motif is a putative binding site for a repressor protein, termed beta protein 1 (BP1) (Berg et al., Nucleic Acids Res 1989;17:8833-8852). Variations in the (AC)n(AT)xTy repeats affect the binding affinity of BP1, thereby altering the expression of the beta-globin gene. Eight different configurations of this repeat motif are identified in our population of Chinese beta-thalassaemia patients. A (AC)3(AT)7T5 motif was identified among these thalassaemia patients and its influence in beta-globin gene expression was studied using stable transfection assay in murine erythroleukemia (MEL) cells. Our data demonstrated that the (AC)3(AT)7T5 motif has a moderately strong repressor effect on the expression of the cis-linked beta-globin gene. The high affinity of BP1 for this motif may result in the suppression of the transcription of the beta-globin gene (Berg et al., Am J Hematol 1991;36:42-47). We postulate that silencer elements in the beta-globin promoter play an important role in modifying the clinical presentation of the disease.

Retinoic acid-induced human secretin gene expression in neuronal cells is mediated by cyclin-dependent kinase 1

Previously, we found that secretin transcript levels were induced by all-trans retinoic acid (RA) in a neuroblastoma cell model, SH-SY5Y. In this article, this RA-dependent upregulation process was further investigated. In the cyclin-dependent kinase 1 (Cdk1) inhibitor-treated cells, the RA-dependent induction of secretin gene expression was inhibited. Together with our previous works, we propose here that the RA responsiveness of the secretin promotor is mediated by two different pathways. The first pathway is by changing the expression levels of NFI-C and Sp proteins while the second pathway is by modifying the phosphorylation status of both NFI-C and Sp proteins via Cdk1.

Lung cancer susceptibility and polymorphisms of glutathione-S-transferase genes in Hong Kong

OBJECTIVE

To study the potential role of genetic polymorphisms of glutathione-S-transferases GSTM1, GSTT1 and GSTP1 in susceptibility to lung cancer in Hong Kong Chinese.

METHODS

229 consecutive incident patients with a histological diagnosis of lung cancer from a regional hospital and 197 healthy population-based controls were recruited for this study between July 1999 and June 2001. Genetic polymorphisms of GSTT1 and GSTM1 were determined using PCR-based technique.

RESULTS

The frequencies of GSTT1 and GSTM1 null genotypes were 51.8 and 59.4% in healthy controls and 63 and 54.7%, respectively, in lung cancer patients. GSTP1 Val105/Val105 genotype was found in only 1% of healthy controls. The risk for lung cancer with GSTT1 null genotype was significantly higher, adjusted odds ratio (OR) 1.69, 95% confidence interval (CI) 1.12-2.56, compared with those with the GSTT1 genotype; the increase in risk was found only in non-smokers. GSTM1 null genotype, combined GSTT1 and GSTM1 null genotype and GSTP1 Val105/Val105 genotype did not confer any increase risk for lung cancer.

CONCLUSION

GSTT1 null genotype is associated with an increased risk for lung cancer in non-smoking Chinese in Hong Kong.

Comparative genome analysis delimits a chromosomal domain and identifies key regulatory elements in the alpha globin cluster

We have cloned, sequenced and annotated segments of DNA spanning the mouse, chicken and pufferfish alpha globin gene clusters and compared them with the corresponding region in man. This has defined a small segment ( approximately 135-155 kb) of synteny and conserved gene order, which may contain all of the elements required to fully regulate alpha globin gene expression from its natural chromosomal environment. Comparing human and mouse sequences using previously described methods failed to identify the known regulatory elements. However, refining these methods by ranking identity scores of non-coding sequences, we found conserved sequences including the previously characterized alpha globin major regulatory element. In chicken and pufferfish, regions that may correspond to this element were found by analysing the distribution of transcription factor binding sites. Regions identified in this way act as strong enhancer elements in expression assays. In addition to delimiting the alpha globin chromosomal domain, this study has enabled us to develop a more sensitive and accurate routine for identifying regulatory elements in the human genome.

Evaluation of beta-globin gene therapy constructs in single copy transgenic mice

Effective gene therapy constructs based on retrovirus or adeno-associated virus vectors will require regulatory elements that direct expression of genes transduced at single copy. Most beta-globin constructs designed for therapy of beta-thalassemias are regulated by the 5'HS2 component of the locus control region (LCR). Here we show that a human beta-globin gene flanked by two small 5'HS2 core elements or flanked by a 5'HS3 (footprints 1-3) core and a 5'HS2 core are not reproducibly expressed in single copy transgenic mice. In addition, low copy transgene concatamers that contain only dimer 5'HS2 cores fail to express, whereas those that contain monomer 5'HS2 cores express at 14% per copy. These data suggest that spacing between HS cores is crucial for LCR activity. We therefore constructed a novel 3.0 kb LCR cassette in which the 5'HS2, 5'HS3 and 5'HS4 cores are each separated by approximately 700 bp. When linked to the 815 bp beta-globin promoter this LCR directs 45% levels of expression from four independent single copy transgenes. However, the 3.0 kb LCR linked to the 265 bp promoter expresses variable levels, averaging 18%, from three single copy transgenes. Our findings suggest that sequences in the distal promoter play a role in single copy transgene activation and that larger LCR and promoter elements are most suitable for gene therapy applications.

A dominant chromatin-opening activity in 5' hypersensitive site 3 of the human beta-globin locus control region

Single-copy human beta-globin transgenes are very susceptible to suppression by position effects of surrounding closed chromatin. However, these position effects are overcome by a 20 kbp DNA fragment containing the locus control region (LCR). Here we show that the 6.5 kbp microlocus LCR cassette reproducibly directs full expression from independent single-copy beta-globin transgenes. By testing individual DNase I-hypersensitive sites (HS) present in the microlocus cassette, we demonstrate that the 1.5 kbp 5'HS2 enhancer fragment does not direct beta-globin expression from single-copy transgenes. In contrast, the 1.9 kbp 5'HS3 fragment directs beta-globin expression in five independent single-copy transgenic mouse lines. Moreover, the 5'HS3 core element and beta-globin proximal promoter sequences are DNase I hypersensitive in fetal liver nuclei of these expressing transgenic lines. Taken together, these results demonstrate that LCR activity is the culmination of at least two separable functions including: (i) a novel activity located in 5'HS3 that dominantly opens and remodels chromatin structure; and (ii) a recessive enhancer activity residing in 5'HS2. We postulate that the different elements of the LCR form a 'holocomplex' that interacts with the individual globin genes.