Hypoxia regulates human lung fibroblast proliferation via p53-dependent and -independent pathways

<p>Abstract</p> <p>Background</p> <p>Hypoxia induces the proliferation of lung fibroblasts in vivo and in vitro. However, the subcellular interactions between hypoxia and expression of tumor suppressor p53 and cyclin-dependent kinase inhibitors p21 and p27 remain unclear.</p> <p>Methods</p> <p>Normal human lung fibroblasts (NHLF) were cultured in a hypoxic chamber or exposed to desferroxamine (DFX). DNA synthesis was measured using bromodeoxyuridine incorporation, and expression of p53, p21 and p27 was measured using real-time RT-PCR and Western blot analysis.</p> <p>Results</p> <p>DNA synthesis was increased by moderate hypoxia (2% oxygen) but was decreased by severe hypoxia (0.1% oxygen) and DFX. Moderate hypoxia decreased p21 synthesis without affecting p53 synthesis, whereas severe hypoxia and DFX increased synthesis of both p21 and p53. p27 protein expression was decreased by severe hypoxia and DFX. Gene silencing of p21 and p27 promoted DNA synthesis at ambient oxygen concentrations. p21 and p53 gene silencing lessened the decrease in DNA synthesis due to severe hypoxia or DFX exposure. p21 gene silencing prevented increased DNA synthesis in moderate hypoxia. p27 protein expression was significantly increased by p53 gene silencing, and was decreased by wild-type p53 gene transfection.</p> <p>Conclusion</p> <p>These results indicate that in NHLF, severe hypoxia leads to cell cycle arrest via the p53-p21 pathway, but that moderate hypoxia enhances cell proliferation via the p21 pathway in a p53-independent manner. In addition, our results suggest that p27 may be involved in compensating for p53 in cultured NHLF proliferation.</p

ISG15 facilitates cellular antiviral response to dengue and west nile virus infection in vitro

<p>Abstract</p> <p>Background</p> <p>Dengue virus (DENV) and West Nile virus (WNV), close siblings of the <it>Flaviviridae </it>family, are the causative agents of Dengue hemorraghic shock or West Nile meningoencephalitis respectively. Vaccines against these two flaviviruses are currently unavailable. Interferon- Stimulated Gene 15 (<it>ISG15</it>), encoding an ubiquitin-like protein, is significantly induced by type I interferons or viral infections. Its roles in viral infections, however, vary with viruses, being either anti- or pro-viral. The exact roles of ISG15 in DENV and WNV infections remain unknown. In the current study, we evaluated the relevancies of ISG15 to DENV and WNV infection of a mouse macrophage cell line RAW264.7.</p> <p>Findings</p> <p>Quantitative PCR showed that mouse <it>Isg15 </it>was dramatically induced in DENV or WNV- infected RAW264.7 cells compared with non-infected cells. <it>Isg15 </it>and two other Jak-Stat related genes, <it>Socs1 </it>and <it>Socs3</it>, were silenced using siRNA mediated RNA interference. The intracellular DENV and WNV loads, as determined by quantitative PCR, were significantly higher in <it>Isg15 </it>silenced cells than control cells. The expression levels of interferon beta 1 (<it>Ifnb1</it>) were increased significantly in <it>Isg15</it>, <it>Socs1 </it>or <it>Socs3 </it>siRNA treated cells. Further investigation indicated that protein modification by ISG15, so called ISGylation, was significantly enhanced in DENV-infected cells compared to that in non-infected cells.</p> <p>Conclusions</p> <p>These findings suggest that ISG15 plays an anti-DENV/WNV function via protein ISGylation.</p

Effect of thong style flip-flops on children’s barefoot walking and jogging kinematics

BACKGROUND: Thong style flip-flops are a popular form of footwear for children. Health professionals relate the wearing of thongs to foot pathology and deformity despite the lack of quantitative evidence to support or refute the benefits or disadvantages of children wearing thongs. The purpose of this study was to compare the effect of thong footwear on children’s barefoot three dimensional foot kinematics during walking and jogging. METHODS: Thirteen healthy children (age 10.3 ± 1.6 SD years) were recruited from the metropolitan area of Sydney Australia following a national press release. Kinematic data were recorded at 200 Hz using a 14 camera motion analysis system (Cortex, Motion Analysis Corporation, Santa Rosa, USA) and simultaneous ground reaction force were measured using a force platform (Model 9281B, Kistler, Winterthur, Switzerland). A three-segment foot model was used to describe three dimensional ankle, midfoot and one dimensional hallux kinematics during the stance sub-phases of contact, midstance and propulsion. RESULTS: Thongs resulted in increased ankle dorsiflexion during contact (by 10.9°, p; = 0.005 walk and by 8.1°, p; = 0.005 jog); increased midfoot plantarflexion during midstance (by 5.0°, p; = 0.037 jog) and propulsion (by 6.7°, p; = 0.044 walk and by 5.4°, p;= 0.020 jog); increased midfoot inversion during contact (by 3.8°, p;= 0.042 jog) and reduced hallux dorsiflexion during walking 10% prior to heel strike (by 6.5°, p; = 0.005) at heel strike (by 4.9°, p; = 0.031) and 10% post toe-off (by 10.7°, p; = 0.001). CONCLUSIONS: Ankle dorsiflexion during the contact phase of walking and jogging, combined with reduced hallux dorsiflexion during walking, suggests a mechanism to retain the thong during weight acceptance. Greater midfoot plantarflexion throughout midstance while walking and throughout midstance and propulsion while jogging may indicate a gripping action to sustain the thong during stance. While these compensations exist, the overall findings suggest that foot motion whilst wearing thongs may be more replicable of barefoot motion than originally thought

OTUB1 Overexpression in Mesangial Cells Is a Novel Regulator in the Pathogenesis of Glomerulonephritis through the Decrease of DCN Level

BACKGROUND: OTUB1 is a member of OTUs (Ovarian-tumor-domain-containing proteases), a deubiquitinating enzymes family (DUBs), which was shown as a proteasome-associated DUB to be involved in the proteins Ub-dependent degradation. It has been reported that OTUB1 was expressed in kidney tissue. But its concrete cellular location and function in the kidney remain unclear. Decorin (DCN) in mesangial cells (MC) is considered to be a potentially important factor for antagonizing glomerulonephritides, and its degradation is mediated by ubiquitination. The aim of this study is to investigate the role of OTUB1 expression in MC and its relationship with DCN during glomerulonephritis. METHODOLOGY/PRINCIPAL FINDINGS: Using quantitative RT-PCR and Western blot, we demonstrated that OTUB1 mRNA and protein were constitutively expressed in cultured rat MC and found to be upregulated by the stimulation of IL-1β or ATS. OTUB1 overexpression was detected in the mesangial area of glomeruli in some immunocomplex mediated nephritides such as IgA nephropathy, acute diffuse proliferative glomerulonephritis and lupus nephritis by immunohistochemistry. The immunoprecipitation assay demonstrated that OTUB1 interacted with DCN. The overexpression of OTUB1 enhanced the ubiquitination and degradation of DCN in MC. CONCLUSION/SIGNIFICANCE: These data showed the inflammatory injury could up-regulate OTUB1 expression in MC, which might attribute the promoting effect of OTUB1 on glomerulonephritides to the decrease of DCN level

Obesity and pronated foot type may increase the risk of chronic plantar heel pain : a matched case-control study

Background : Chronic plantar heel pain (CPHP) is one of the most common musculoskeletal disorders of the foot, yet its aetiology is poorly understood. The purpose of this study was to examine the association between CPHP and a number of commonly hypothesised causative factors.Methods : Eighty participants with CPHP (33 males, 47 females, mean age 52.3 years, S.D. 11.7) were matched by age (&plusmn; 2 years) and sex to 80 control participants (33 males, 47 females, mean age 51.9 years, S.D. 11.8). The two groups were then compared on body mass index (BMI), foot posture as measured by the Foot Posture Index (FPI), ankle dorsiflexion range of motion (ROM) as measured by the Dorsiflexion Lunge Test, occupational lower limb stress using the Occupational Rating Scale and calf endurance using the Standing Heel Rise Test.Results : Univariate analysis demonstrated that the CPHP group had significantly greater BMI (29.8 &plusmn; 5.4 kg/m2 vs. 27.5 &plusmn; 4.9 kg/m2; P &lt; 0.01), a more pronated foot posture (FPI score 2.4 &plusmn; 3.3 vs. 1.1 &plusmn; 2.3; P &lt; 0.01) and greater ankle dorsiflexion ROM (45.1 &plusmn; 7.1&deg; vs. 40.5 &plusmn; 6.6&deg;; P &lt; 0.01) than the control group. No difference was identified between the groups for calf endurance or time spent sitting, standing, walking on uneven ground, squatting, climbing or lifting. Multivariate logistic regression revealed that those with CPHP were more likely to be obese (BMI &ge; 30 kg/m2) (OR 2.9, 95% CI 1.4 &ndash; 6.1, P &lt; 0.01) and to have a pronated foot posture (FPI &ge; 4) (OR 3.7, 95% CI 1.6 &ndash; 8.7, P &lt; 0.01).Conclusion : Obesity and pronated foot posture are associated with CPHP and may be risk factors for the development of the condition. Decreased ankle dorsiflexion, calf endurance and occupational lower limb stress may not play a role in CPHP.<br /

Inhibition of Interferon Induction and Action by the Nairovirus Nairobi Sheep Disease Virus/Ganjam Virus

The Nairoviruses are an important group of tick-borne viruses that includes pathogens of man (Crimean Congo hemorrhagic fever virus) and livestock animals (Dugbe virus, Nairobi sheep disease virus (NSDV)). NSDV is found in large parts of East Africa and the Indian subcontinent (where it is known as Ganjam virus). We have investigated the ability of NSDV to antagonise the induction and actions of interferon. Both pathogenic and apathogenic isolates could actively inhibit the induction of type 1 interferon, and also blocked the signalling pathways of both type 1 and type 2 interferons. Using transient expression of viral proteins or sections of viral proteins, these activities all mapped to the ovarian tumour-like protease domain (OTU) found in the viral RNA polymerase. Virus infection, or expression of this OTU domain in transfected cells, led to a great reduction in the incorporation of ubiquitin or ISG15 protein into host cell proteins. Point mutations in the OTU that inhibited the protease activity also prevented it from antagonising interferon induction and action. Interestingly, a mutation at a peripheral site, which had little apparent effect on the ability of the OTU to inhibit ubiquitination and ISG15ylation, removed the ability of the OTU to block the induction of type 1 and the action of type 2 interferons, but had a lesser effect on the ability to block type 1 interferon action, suggesting that targets other than ubiquitin and ISG15 may be involved in the actions of the viral OTU