Inhibitory effects of rosiglitazone on lipopolysaccharide-induced inflammation in a murine model and HK-2 cells

BACKGROUND

Inflammation may play an important role in the pathogenesis of kidney disease. Agonists of the peroxisome proliferator-activated receptor-γ (PPAR-γ), such as rosiglitazone, have been recently demonstrated to regulate inflammation by modulating the production of inflammatory mediators. The purpose of this study was to examine the effects of rosiglitazone on lipopolysaccharide (LPS)-induced kidney inflammation and to explore the mechanism of its renoprotection.

METHODS

Mice were treated with LPS with or without pretreatment with rosiglitazone. Blood urea nitrogen (BUN), creatinine levels, the urinary albumin-to-creatinine ratio, macrophage infiltration, monocyte chemoattractant protein-1 (MCP-1) expression, PPAR-γ expression, and NF-κB and PPAR-γ activity were investigated. HK-2 cells were maintained under defined in vitro conditions, treated with either rosiglitazone and/or the PPAR-γ antagonist GW9662, and then stimulated with LPS. MCP-1, IL-8, IL-6, NF-κB activity and PPAR-γ expression were investigated.

RESULTS

Compared to the LPS only group, pretreatment with rosiglitazone in vivo significantly attenuated the BUN levels macrophage infiltration, MCP-1 overexpression and NF-κB activity (p < 0.05). Rosiglitazone also restored PPAR-γ expression and protein activity, which were reduced significantly in the LPS only group (p < 0.05). Furthermore, in the LPS-stimulated HK-2 cells, rosiglitazone downregulated MCP-1, IL-8 and IL-6 expression as well as NF-κB activation and increased PPAR-γ expression (p < 0.05). These effects were diminished by GW9662.

CONCLUSION

These results showed that pretreatment with rosiglitazone could attenuate kidney inflammation through the activation of PPAR-γ, suppression of MCP-1 overproduction and NF-κB activation. Rosiglitazone had a protective effect via a PPAR-γ-dependent pathway in LPS-treated HK-2 cells.

A novel anti-ageing mechanism for retinol: induction of dermal elastin synthesis and elastin fibre formation

Dermal elastic fibres are extracellular matrix protein complexes produced by fibroblasts and involved in skin elasticity. Elastin fibres decrease with age as a result of reduced synthesis and increased degradation, resulting in skin sagging and reduced skin elasticity. In this study, we show that retinol (ROL), known to enhance dermal collagen production, is also enhancing elastin fibre formation. ROL induced elastin gene expression and elastin fibre formation in cultured human dermal fibroblasts. Topical treatment of cultured human skin explants with a low dose (0.04%) of ROL increased mRNA and protein levels of tropoelastin and of fibrillin-1, an elastin accessory protein, as documented by QPCR and immunohistochemistry staining. Luna staining confirmed the increased elastin fibre network in the ROL-treated skin explants, as compared with untreated controls. These data demonstrate that ROL exerts its anti-ageing benefits not only via enhanced epidermal proliferation and increased collagen production, but also through an increase in elastin production and assembly.

Body fat distribution and their associations with cardiovascular risk, insulin resistance and β-cell function: are there differences between men and women?

OBJECTIVE

The objective was to examine the independent and gender-specific effects of WC and BMI on CVD risk factors, insulin resistance and β-cell function.

DESIGN

A cross-sectional study of 2931 adults aged 20-79 years was carried out in Fujian province by multi-stratified sampling from July 2007 to May 2008. Gender-specific differences of WC and BMI on CVD risk factors, insulin resistance and β-cell function were displayed jointly by WC and BMI tertiles. The homeostasis model assessment of insulin resistance (HOMA-IR) index and the quantitative insulin-sensitivity check index (QUICKI): l/(log G0 ± log I0) were used to estimate insulin sensitivity; insulin secretion was assessed using the HOMA-β index; β-cell function was quantified as the ratio of the incremental insulin to glucose responses over the first 30 min during the OGTT (△I30/△G30). The oral disposition index (DIo) was calculated as ΔI(30) /ΔG(30) × 1/fasting insulin. The Matsuda index is defined as 10,000/sqrt (FBG × FPI × [G × I]) where FPG is fasting glucose, FPI is fasting insulin, G is mean glucose during the OGTT (calculated from glucose samples at 0, 30, and 120 min), and I is mean insulin during the OGTT (calculated from insulin samples at 0, 30, and 120 min).

RESULTS

Waist circumference and BMI correlated with each other in both men (0.756, p < 0.001) and women (0.728, p < 0.001). The two indexes were independently associated with CVD risk factors (such as hypertension, metabolic syndrome, and dyslipidaemia) in both men and women. BMI was better than WC in assessing the risk of diabetes in men (p = 0.003 for BMI, and p = 0.234 for WC), while WC was better than BMI in predicting diabetes in women (p < 0.001 for WC, and p = 0.831 for BMI). There were significant associations between BMI and insulin resistance or β-cell function even after adjustment for WC except for DIo in male subjects, but WC only associated with HOMA-IR positively or the Matsuda index and QUICKI negatively after adjustment for BMI. For women, associations between WC and insulin resistance or β-cell function remained strong even after adjustment for BMI besides DIo. However, there were no independent relations of BMI to insulin resistance and β-cell function except for Matsuda index with a significant negative association after adjustment for WC in women.

CONCLUSION

Body mass index and WC were independently associated with CVD risk factors. There were differences in the gender-specific relevance of measures of body fat distribution in assessing the insulin resistance, β-cell function and thus the risk of diabetes. Therefore, WC should be measured in addition to BMI to assess CVD risk accurately and implement efficient treatment strategies.

Investigations of mechanical vibrations for beamlines at the Canadian Light Source

Vibration is often a problem causing poor quality of photon beams at synchrotron radiation facilities, since beamlines are quite sensitive to vibrations. Therefore, vibration analysis and control at synchrotron radiation facilities is crucial. This paper presents investigations on mechanical vibrations at four beamlines and endstations at the Canadian Light Source, i.e. the Canadian Macromolecular Crystallography Facility 08ID-1 beamline, the Hard X-ray MicroAnalysis 06ID-1 beamline, the Resonant Elastic and Inelastic Soft X-ray Scattering 10ID-2 beamline, and the Scanning Transmission X-ray Microscope endstation at the Spectromicroscopy 10ID-1 beamline. This study identifies vibration sources and investigates the influence of mechanical vibrations on beamline performance. The results show that vibrations caused by movable mechanical equipment significantly affect the data acquired from beamlines.

Enhanced tumor therapy using vaccinia virus strain GLV-1h68 in combination with a β-galactosidase-activatable prodrug seco-analog of duocarmycin SA

Breast cancer is the most common cause of cancer-related death worldwide, thus remaining a crucial health problem among women despite advances in conventional therapy. Therefore, new alternative strategies are needed for effective diagnosis and treatment. One approach is the use of oncolytic viruses for gene-directed enzyme prodrug therapy. Here, the lacZ-carrying vaccinia virus (VACV) strain GLV-1h68 was used in combination with a β-galactosidase-activatable prodrug derived from a seco-analog of the natural antibiotic duocarmycin SA. Tumor cell infection with the VACV strain GLV-1h68 led to production of β-galactosidase, essential for the conversion of the prodrug to the toxic compound. Furthermore, drug-dependent cell kill and induction of the intrinsic apoptosis pathway in tumor cells was also observed on combination therapy using the prodrug and the GLV-1h68 strain, despite the fact that VACV strains encode antiapoptotic proteins. Moreover, GI-101A breast cancer xenografts were effectively treated by the combination therapy. In conclusion, the combination of a β-galactosidase-activatable prodrug with a tumor-specific vaccinica virus strain encoding this enzyme, induced apoptosis in cultures of the human GI-101A breast cancer cells, in which a synergistic oncolytic effect was observed. Moreover, in vivo, additional prodrug treatment had beneficial effects on tumor regression in GLV-1h68-treated GI-101A-xenografted mice.

The protein kinase Pak4 disrupts mammary acinar architecture and promotes mammary tumorigenesis

The Pak4 serine/threonine kinase is highly expressed in many cancer cell lines and human tumors. While several studies have addressed the role for Pak4 in transformation of fibroblasts, most human cancers are epithelial in origin. Epithelial cancers are associated not only with changes in cell growth, but also with changes in the cellular organization within the three dimensional (3D) architecture of the affected tissues. Here we used immortalized mouse mammary epithelial cells (iMMECs) as a model system to study the role for Pak4 in mammary tumorigenesis. iMMECs are an excellent model system for studying breast cancer they can grow in 3D-epithelial cell culture, where they form acinar structures that recapitulate in vivo mammary morphogenesis. While Pak4 is expressed at low levels in wild type iMMECs, it is overexpressed in response to oncogenes, such as oncogenic Ras and Her2/neu. Here we found that overexpression of Pak4 in iMMECs leads to changes in 3D acinar architecture that are consistent with oncogenic transformation. These include decreased central acinar cell death, abrogation of lumen formation, cell polarity alterations, and deregulation of acinar size and cell number. Furthermore, iMMECs overexpressing Pak4 form tumors when implanted into the fat pads of athymic mice. Our results suggest that overexpression of Pak4 triggers events that are important for the transformation of mammary epithelial cells. This is likely to be due to the ability of Pak4 to inhibit apoptosis and promote cell survival, and thus subsequent uncontrolled proliferation, and to its ability to deregulate cell shape and polarity.