Isthmin is a novel secreted angiogenesis inhibitor that inhibits tumour growth in mice

Anti-angiogenesis represents a promising therapeutic strategy for the treatment of various malignancies. Isthmin (ISM) is a gene highly expressed in the isthmus of the midbrain–hindbrain organizer in Xenopus with no known functions. It encodes a secreted 60 kD protein containing a thrombospondin type 1 repeat domain in the central region and an adhesion-associated domain in MUC4 and other proteins (AMOP) domain at the C-terminal. In this work, we demonstrate that ISM is a novel angiogenesis inhibitor. Recombinant mouse ISM inhibited endothelial cell (EC) capillary network formation on Matrigel through its C-terminal AMOP domain. It also suppressed vascular endothelial growth factor (VEGF)-basic fibroblast growth factor (bFGF) induced in vivo angiogenesis in mouse. It mitigated VEGF-stimulated EC proliferation without affecting EC migration. Furthermore, ISM induced EC apoptosis in the presence of VEGF through a caspase-dependent pathway. ISM binds to αvβ5 integrin on EC surface and supports EC adhesion. Overexpression of ISM significantly suppressed mouse B16 melanoma tumour growth through inhibition of tumour angiogenesis without affecting tumour cell proliferation. Knockdown of isthmin in zebrafish embryos using morpholino antisense oligonucleotides led to disorganized intersegmen-tal vessels in the trunk. Our results demonstrate that ISM is a novel endogenous angiogenesis inhibitor with functions likely in physiological as well as pathological angiogenesis.

miRNA studies in in vitro and in vivo activated hepatic stellate cells

AIM

To understand which and how different miRNAs are implicated in the process of hepatic stellate cell (HSC) activation.

METHODS

We used microarrays to examine the differential expression of miRNAs during in vitro activation of primary HSCs (pHSCs). The transcriptome changes upon stable transfection of rno-miR-146a into an HSC cell line were studied using cDNA microarrays. Selected differentially regulated miRNAs were investigated by quantitative real-time polymerase chain reaction during in vivo HSC activation. The effect of miRNA mimics and inhibitor on the in vitro activation of pHSCs was also evaluated.

RESULTS

We found that 16 miRNAs were upregulated and 26 were downregulated significantly in 10-d in vitro activated pHSCs in comparison to quiescent pHSCs. Overexpression of rno-miR-146a was characterized by marked upregulation of tissue inhibitor of metalloproteinase-3, which is implicated in the regulation of tumor necrosis factor-α activity. Differences in the regulation of selected miRNAs were observed comparing in vitro and in vivo HSC activation. Treatment with miR-26a and 29a mimics, and miR-214 inhibitor during in vitro activation of pHSCs induced significant downregulation of collagen type I transcription.

CONCLUSION

Our results emphasize the different regulation of miRNAs in in vitro and in vivo activated pHSCs. We also showed that miR-26a, 29a and 214 are involved in the regulation of collagen type I mRNA.

miRNA studies in in vitro and in vivo activated hepatic stellate cells

AIM

To understand which and how different miRNAs are implicated in the process of hepatic stellate cell (HSC) activation.

METHODS

We used microarrays to examine the differential expression of miRNAs during in vitro activation of primary HSCs (pHSCs). The transcriptome changes upon stable transfection of rno-miR-146a into an HSC cell line were studied using cDNA microarrays. Selected differentially regulated miRNAs were investigated by quantitative real-time polymerase chain reaction during in vivo HSC activation. The effect of miRNA mimics and inhibitor on the in vitro activation of pHSCs was also evaluated.

RESULTS

We found that 16 miRNAs were upregulated and 26 were downregulated significantly in 10-d in vitro activated pHSCs in comparison to quiescent pHSCs. Overexpression of rno-miR-146a was characterized by marked upregulation of tissue inhibitor of metalloproteinase-3, which is implicated in the regulation of tumor necrosis factor-α activity. Differences in the regulation of selected miRNAs were observed comparing in vitro and in vivo HSC activation. Treatment with miR-26a and 29a mimics, and miR-214 inhibitor during in vitro activation of pHSCs induced significant downregulation of collagen type I transcription.

CONCLUSION

Our results emphasize the different regulation of miRNAs in in vitro and in vivo activated pHSCs. We also showed that miR-26a, 29a and 214 are involved in the regulation of collagen type I mRNA.

[The preliminary study of incorporating tetrapod-like zinc oxide whisker on the antibacterial activity of soft denture liners]

OBJECTIVE

To research the effects of incorporating tetrapod-like zinc oxide whisker (T-ZnOw) of different proportions on the antibacterial activity of different kinds of soft denture liners.

METHODS

The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of T-ZnOw against Saccharomyces albicans (S. albicans) were examined by the broth dilution test. Add T-ZnOw 0%, 1%, 2%, 3% to Silagum soft denture liners and soft denture liners respectively. The antimicrobial rate of S. albicans was determined by the membrane covering method.

RESULTS

The MIC of T-ZnOw against S. albicans was 78 microg mL(-1) and the MBC was 156 microg mL(-1). Comparing 1%, 2%, 3% T-ZnOw group with control group, the results showed significant difference (P<0.05). And as the T-ZnOw antibacterial agent added ratio increased, antibacterial increased significantly.

CONCLUSION

The soft denture liners incorporating with 1%, 2%, 3% of T-ZnOw can improve antibacterial activity. Following the increased proportions of T-ZnOw, antibacterial rate was significantly increasing.

Alterations in fibrosis-related gene expression and proteomic expression profile in rat hepatic stellate cells exposed to the cocktail

AIM: To investigate changes in the expression of fibrosis-related genes and proteomic expression profile in rat hepatic stellate cells (HSCs) exposed to the cocktail to explore potential anti-hepatic fibrosis mechanisms of the cocktail therapy.

METHODS: After HSCs were cultured in vitro and exposed to the cocktail for 24 h, the expression of TGF-β1, MMP-2 and TIMP-2 mRNAs and proteomic expression profile were measured by RT-PCR and SELDI-TOF-MS, respectively.

RESULTS: Compared to control cells, the expression level of MMP-2 mRNA significantly increased (0.094 ± 0.051 vs 0.023 ± 0.056, P < 0.05), and those of TGF-β1 and TIMP-2 mRNAs significantly decreased (0.301 ± 0.025 vs 0.503 ± 0.042; 0.719 ± 0.03 vs 1.204 ± 0.418, both P < 0.05) in HSCs exposed to the cocktail. A total of 176 differential proteins were identified between control cells and treated cells, of which 32 were up-regulated and 3 down-regulated.

CONCLUSION: The cocktail therapy exerts anti-hepatic fibrosis activity possibly by regulating the expression of related genes and proteins.

Quantitative analysis of pupillary light reflex by real-time autofluorescent imaging in a diabetic mouse model

Here we (i) introduce a novel laser-based quantitative method of measuring pupillary light reflex (PLR) and applied it for the in vivo PLR monitoring of early diabetic retinopathy (DR) in a mouse model, (ii) investigate if melanopsin-expressing retinal ganglion cells (mRGCs) are implicated in the early progression of DR and, if so, is there an impact on PLR and (iii) determine if changes in PLR precede the onset of retinal hypoperfusion. A base-line PLR measurement is captured from C57BL/6J wild type mice followed by a single intraperitoneal administration of 200 mg/kg streptozotocin (STZ) and citrate buffer (vehicle) for the "diabetic" (n=5) and "control" (n=5) mice respectively, the very next day. PLR measurements are repeated once a week for four weeks. The PLR data comprises retinal autofluorescence intensity (AFI) values sampled over a 5-min period under confocal excitation with 488 nm high intensity blue laser light. AFI is used here as an indirect measure of pupil size since the amount of excitation light entering and emission light leaving the eye is proportional to the pupil area. Immunohistochemistry (IHC) staining of mRGCs and RT-PCR of melanopsin mRNA are performed at the end-point. The vascular calibre of both control and STZ-treated diabetic mice is assessed via in vivo fluorescein angiography (FA) on day 0 (base-line), 1/2, 1 and 4 months post-STZ treatment. The PLR profile shows a more rapid pupil constriction and slower dilation in diabetic mice compared to the control. Changes in PLR coincide or even precede the onset of retinal hypoperfusion. Extensive dendritic network of the mRGCs in retinal whole-mounts and increased melanopsin mRNA from the whole eye are also observed in diabetic mice. These pathological changes to mRGCs during early DR may in turn contribute towards changes in PLR. We present here a quantitative method of measuring PLR which enables an early detection of DR with potential application in the clinical setting. In contrast to conventional measurements of PLR, we are able to calibrate the amount of light reaching the retina which is a crucial parameter in longitudinal studies.

Effects of cocktail therapy on TGF-β1, COL I and COL III expression in liver fibrosis in rats

AIM: To investigate the effects of cocktail therapy on the expression of transforming growth factor-β1 (TGF-β1), collagen I (COL I) and collagen III (COL III) in carbon tetrachloride-induced liver fibrosis in rats.

METHODS: Hepatic fibrosis was induced in rats with carbon tetrachloride. Wistar rats were divided into 7 groups: normal group, model group, colchicine group, taurine group, epigallocatechin gallate (EGCG) group, genistein group and cocktail therapy group. The rats were sacrificed at week 10 after treatment. The deposition of collagen in liver tissue was observed by HE staining. The expression of TGF-β1, COL I and COL III in hepatic tissue was detected by immunohistochemistry.

RESULTS: A significant reduction in collagen deposition and disorganization was noted in the cocktail therapy group when compared with the model group. The expression levels of TGF-β1, COL I and COL III in the cocktail therapy group, genistein group, EGCG group and taurine group, compared with the model group, markedly decreased (TGF-β1: 2.57 ± 0.23, 4.21 ± 0.35, 4.93 ± 0.21 and 4.81 ± 0.16 vs 12.11 ± 0.62, all P < 0.05; COL I: 2.69 ± 0.10, 4.88 ± 0.42, 5.04 ± 0.31 and 4.79 ± 0.29 vs 13.06 ± 0.24, all P < 0.05; COL III: 3.17 ± 0.42, 5.73 ± 0.23, 5.51 ± 0.25 and 5.24 ± 0.18 vs 15.15 ± 0.43, all P < 0.05). Cocktail therapy had a more significant inhibitory effect on the expression of these proteins than other agents tested (all P < 0.05).

CONCLUSION: Cocktail therapy has an obvious protective effect against liver fibrosis in rats possibly by remarkably inhibiting TGF-β1, COL I and COL III expression in liver tissue.

Imidazolium salt (DBZIM) reduces gliosis in mice treated with neurotoxicant 2'-CH(3) -MPTP

We have recently identified a class of imidazolium salts (IMSs) with antioxidative property and can function as scavengers for radical oxygen species (ROS) [18]. Here, we investigate one of the IMSs, 1,3-bisbenzylimidazolium bromide (DBZIM), for its possible role in attenuating neurotoxicity and gliosis in the retina and the brain induced by a Parkinsonian neurtoxicant, methyl-4(2'-methylphenyl)-1,2,3,6-tetrahydropyridine (2'-CH(3) -MPTP), which is a free radical generating agent. In this study, we employ a molecular retinal imaging method, which we recently developed in a transgenic mouse model expressing green fluorescent protein (GFP) under the control of glial fibrillary acidic protein (GFAP) promoter [14], to assess the efficacy of DBZIM, since currently no in vitro system with a sufficient complexity is available for accurately assessing a compound's efficacy. The longitudinal imaging results showed DBZIM can effectively suppress the neurotoxicant-induced retinal gliosis. Immunohistochemistry performed on the postmodern mouse brain confirmed that DBZIM also reduced striatal gliosis, and concomitantly attenuated the loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc). These findings suggest that DBZIM could be a useful small molecular compound for studying neurotoxicity and neuroprotection in the retina and the brain.

Effects of cocktail therapy on cell proliferation and Collagen I and TIMP-1 mRNA expression in rat hepatic stellate cells

AIM: To investigate the effects of cocktail therapy on cell proliferation and collagen I (Col I) and tissue inhibitor of metalloproteinase-1 (TIMP-1) mRNA expression in rat hepatic stellate cells.

METHODS: Hepatic stellate cells (HSC-T6) cultured in vitro were exposed to taurine (taurine group), epigallocatechin gallate (EGCG; EGCG group), genistein (genistein group), and a combination of these three drugs (cocktail-treated group) for 24 h, respectively. Cell proliferation was determined by methyl thiazol tetrazolium (MTT) assay. The expression of Col I and TIMP-1 mRNAs was measured by semi-quantitative reverse-transcription polymerase chain reaction (RT-PCR).

RESULTS: Cell proliferation was significantly inhibited in the taurine group, EGCG group, genistein group and cocktail-treated group compared with the control group (0.237 ± 0.007, 0.216 ± 0.009, 0.242 ± 0.008 and 0.130 ± 0.004 vs 0.452 ± 0.011, respectively; all P < 0.05). The reduced rate of cell proliferation was more significant in the cocktail-treated group than in other treatment groups (all P < 0.05). The expression levels of Col I and TIMP-1 mRNAs markedly decreased in all treatment groups when compared with the control group (all P < 0.05). The expression levels of Col I and TIMP-1 mRNAs were significantly lower in the cocktail-treated group than in other treatment groups (P < 0.05).

CONCLUSION: Cocktail therapy significantly inhibits cell proliferation and down-regulates Col I and TIMP-1 mRNA expression in HSCs. Cocktail therapy may be more effective than monotherapy in the treatment of liver fibrosis.

In vivo imaging of retinal gliosis: a platform for diagnosis of PD and Screening of anti-PD compounds

Parkinson's disease (PD) is the second most frequent degenerative disorder after Alzheimer's disease. It is characterized by the depletion of mesenchephalic dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc) and striatal dopamine. Oxidative stress plays a major role in the pathogenesis of Parkinson's disease where DA neurons are especially vulnerable to excessive production of the H2O2 reactive oxygen species. Unfortunately, the first clinical symptoms of PD occur after at least 60-80% of nigro-striatal dopaminergic neurons have lost their function. Therefore, early detection of PD is critical in slowing down the progression of the disease and enabling the development of therapeutic compounds which could intervene at an earlier stage. Here, we employ in vivo molecular imaging of astrocytic retinal gliosis in a transgenic mice to longitudinally monitor the progression of MPTP-induced PD. We have quantitatively evaluated, via this imaging platform, the efficacy of a synthetic antioxidant, 1,3- bisbenzylimidazolium bromide (DBZIM), in protecting the DA neurons and scavenging the ROS. We show here that MPTPinduced PD results in an upregulation of glial fibrillary acidic protein (GFAP), a marker for gliosis, by 36% relative to saline whereas gliosis is normalized in MPTP-induced PD mice treated with DBZIM.

Comparison of risk factors associated with hypertension subtypes by classification tree method in Tongshan County of Jiangsu Province, China

BACKGROUND

There are only a very limited number of studies relating to risk factors for hypertension in rural populations in China. There are even fewer studies comparing various hypertension subtypes.

METHODS

A cross-sectional investigation was carried out in a representative sample of 20,390 subjects drawn from among 1,180,000 adult residents of Tongshan County of Jiangsu Province, China. The impact of risk factors including demographic, socioeconomic, dietary, and behavioral, on three hypertension subtypes, namely, isolated systolic hypertension (ISH), isolated diastolic hypertension (IDH), and systolic-diastolic hypertension (SDH), was analyzed by applying statistical tests and a classification tree.

RESULTS

ISH was the predominant untreated hypertension subtype (13.68 +/- 0.24%) in the adults of Tongshan County, followed by SDH (11.70 +/- 0.23%) and IDH (6.24 +/- 0.17%). Age, number of cigarettes smoked daily, and the types of vitamins taken varied among the ISH, IDH, and SDH classification trees. Low socioeconomic status was associated with an increased risk for ISH and SDH. Light alcohol intake was associated with higher risk for ISH, but with lower risks for IDH and SDH. Light cigarette smoking was associated with higher ISH risk but lower SDH risk. The intake of appropriate amounts of fish, shrimp, or meat lowered the risks for ISH and IDH. The intake of appropriate amounts of seafood, eggs, milk, or fruit lowered the risks for all hypertension subtypes. Interestingly, an excessive preference for sweet or salty foods was associated with a higher risk for all the subtypes.

CONCLUSIONS

In Tongshan County, there was a considerable prevalence of hypertension of various subtypes, each associated with distinctive and complex risk factors. This suggests that there is a need for testing more diverse prevention measures, tailored to specific subtypes.

TGF-beta1 down-regulates connexin 43 expression and gap junction intercellular communication in rat hepatic stellate cells

Intercellular communication is an important tool used by the cells to effectively regulate concerted responses. Hepatic stellate cells (HSCs) communicate to each other through functional gap junctions composed of connexin 43 (Cx43) proteins. We show that exogenous human TGF-beta1 (hTGF-beta1), a pro-fibrotic stimulus, decreases Cx43 mRNA and protein in a rat HSC cell line and primary HSCs. Furthermore, hTGF-beta1 increases the phosphorylation of Cx43 at serine 368. These effects lead to a decrease in the gap junction intercellular communication between the HSCs, as shown by gap-FRAP analysis. We also observe the binding of Snai1, from the nuclear extract of HSCs, to a Snai1 consensus sequence in the Cx43 promoter. In the same context, Snai1 siRNA transfection results in an up-regulation of Cx43 suggesting that TGF-beta1 may regulate Cx43 via Snai1. In addition, we demonstrate that the knockdown of Cx43 by siRNA transfection results in a slower proliferation of HSCs. These findings illuminate a new effect of TGF-beta1 in HSCs, namely the regulation of intercellular communication by affecting the expression level and the phosphorylation state of Cx43 through Snai1 signaling.

A class of imidazolium salts is anti-oxidative and anti-fibrotic in hepatic stellate cells

A class of imidazolium salts (IMSs) is routinely used in organic synthetic chemistry as precursors to generate N-heterocyclic carbenes (NHCs) with catalytic activity. However, their biological properties are largely unknown. The current study investigates the biological activity of a typical NHC precursor DBZIM and its trimer TDBZIM in hepatic stellate cells (HSCs), which is an in vitro model for studying liver fibrosis. The results show that HSCs treated with IMSs have an enhanced GSH/GSSG ratio and a reduced level of reactive oxygen species (ROS), which may consequently contribute to the attenuation in gene expression of fibrogenic molecules such as smooth muscle actin-alpha (SMAA), transforming growth factor-beta 1 (TGF-beta1), procollagen alphaI(I) and fibronectin. Further, the in vivo experiments demonstrate that DBZIM is an anti-fibrotic agent in a mouse model of liver fibrosis. These findings suggest that the versatile IMSs could be a potential source for developing novel therapeutics to treat liver fibrosis and other fibrogenic disorders caused by oxidative stress and TGF-beta1 mal-signalling.

Glial fibrillary acidic protein promoter targets pancreatic stellate cells

BACKGROUND

Pancreatic fibrosis is one of the clinical manifestations of chronic pancreatitis and pancreatic cancer. Pancreatic stellate cells (PSCs) have been recognised as principal effector cells in the development of pancreatic fibrosis. The ability to specifically address PSCs might offer a potential for developing a targeted therapy for pancreatic fibrosis.

AIM

Characterisation of the 2.2kb hGFAP (human glial fibrillary acidic protein) promoter for its usefulness to express reporter genes specifically in PSCs in vitro and in vivo.

METHODS

2.2kb hGFAP-LacZ reporter expressions were examined in four immortalised PSC lines and two non-PSCs, meanwhile, GFAP-LacZ transgenic mice were used to detect LacZ reporter in pancreas tissue. Several kinase inhibitors, vitamin A and its metabolites were applied to study the regulation of 2.2kb hGFAP promoter in PSCs.

RESULTS

Our results showed that the 2.2kb hGFAP promoter is capable of regulating the expression of reporter genes exclusively in immortalised and primary PSCs, as well as in PSCs of transgenic GFAP-LacZ mice. When a PSC cell line transfected with the LacZ reporter (SAM-K/LacZ/C1) was treated with different anti-fibrotic agents and kinase inhibitors, the transgenic beta-galactosidase activity was found to be regulated by multiple signalling pathways known to be involved in the PSC activation.

CONCLUSIONS

This study provides the proof of concept for using the 2.2kb hGFAP promoter to specifically manipulate PSCs for the development of targeted gene and/or drug therapy in pancreatic fibrosis, and for the screening of anti-fibrotic agents.

Development of dual-compartment perfusion bioreactor for serial coculture of hepatocytes and stellate cells in poly(lactic-co-glycolic acid)-collagen scaffolds

An important challenge in liver tissue engineering is to overcome the rapid loss of hepatocyte functions. In vivo, hepatocytes are compact polyhedral cells with round nuclei; however, they readily loss many of their differentiated functions in vitro. To overcome this challenge, we have established a new perfusion bioreactor that consists of two compartments which enabled the serial coculture of hepatocytes and hepatic stellate cells-T6 without direct contact between each other. Three dimensional scaffolds were utilized in the bioreactor as physical anchors for cells. The scaffolds consist of collagen grafted poly(lactic-co-glycolic acid) microfibers and cross-linked collagen sponges between microfibers for additional cellular support and adhesion. The advantages of this new bioreactor are enabling cell culture in three dimensional organization and controlling the culture parameters of the supporting cells independently from the hepatocytes. The results showed that the hepatocytes exhibited much higher levels of the differentiated functions such as albumin secretion, urea synthesis, and cytochrome P450 enzymatic activity when compared with the monoculture system where hepatocytes alone were cultured. This perfusion bioreactor system has potential applications in the development of bioartificial liver devices or cell-based tissue constructs transplantation therapies.

A thixotropic nanocomposite gel for three-dimensional cell culture

Thixotropic materials, which become less viscous under stress and return to their original state when stress is removed, have been used to deliver gel-cell constructs and therapeutic agents. Here we show that a polymer-silica nanocomposite thixotropic gel can be used as a three-dimensional cell culture material. The gel liquefies when vortexed--allowing cells and biological components to be added--and resolidifies to trap the components when the shear force from spinning is removed. Good permeability of nutrients and gases through the gel allows various cell types to proliferate and be viable for up to three weeks. Human mesenchymal stem cells cultured in stiffer gels developed bone-like behaviour, showing that the rheological properties of the gel can control cell differentiation. No enzymatic, chemical, or photo-crosslinking, changes in ionic strength or temperature are required to form or liquefy the gel, offering a way to sub-culture cells without using trypsin-a protease commonly used in traditional cell culture techniques.

Nuclear cathepsin F regulates activation markers in rat hepatic stellate cells

Activation of hepatic stellate cells during liver fibrosis is a major event facilitating an increase in extracellular matrix deposition. The up-regulation of smooth muscle alpha-actin and collagen type I is indicative of the activation process. The involvement of cysteine cathepsins, a class of lysosomal cysteine proteases, has not been studied in conjunction with the activation process of hepatic stellate cells. Here we report a nuclear cysteine protease activity partially attributed to cathepsin F, which co-localizes with nuclear speckles. This activity can be regulated by treatment with retinol/palmitic acid, known to reduce the hepatic stellate cell activation. The treatment for 48 h leads to a decrease in activity, which is coupled to an increase in cystatin B and C transcripts. Cystatin B knockdown experiments during the same treatment confirm the regulation of the nuclear activity by cystatin B. We demonstrate further that the inhibition of the nuclear activity by E-64d, a cysteine protease inhibitor, results in a differential regulation of smooth muscle alpha-actin and collagen type I transcripts. On the other hand, cathepsin F small interfering RNA transfection leads to a decrease in nuclear activity and a transcriptional down-regulation of both activation markers. These findings indicate a possible link between nuclear cathepsin F activity and the transcriptional regulation of hepatic stellate cell activation markers.