Chemokines in tissue fibrosis

Fibrosis or scarring of diverse organs and tissues is considered as a pathologic consequence of a chronically altered wound healing response which is tightly linked to inflammation and angiogenesis. The recruitment of immune cells, local proliferation of fibroblasts and the consecutive accumulation of extracellular matrix proteins are common pathophysiological hallmarks of tissue fibrosis, irrespective of the organ involved. Chemokines, a family of chemotactic cytokines, appear to be central mediators of the initiation as well as progression of these biological processes. Traditionally chemokines have only been considered to play a critical role in orchestrating the influx of immune cells to sites of tissue injury. However, within the last years, further aspects of chemokine biology including fibroblast activation and angiogenesis have been deciphered in tissue fibrosis of many different organs. Interestingly, certain chemokines appear to mediate common effects in liver, kidney, lung, and skin of various animal models, while others mediate tissue specific effects. These aspects have to be kept in mind when extrapolating data of animal studies to early human trials. Nevertheless, the further understanding of chemokine effects in tissue fibrosis might be an attractive approach for identifying novel therapeutic targets in chronic organ damage associated with high morbidity and mortality. This article is part of a Special Issue entitled: Fibrosis: Translation of basic research to human disease.     

Vegetative Compatibility,Pathogenicity and Virulence Diversity of Fusarium oxysporum f. sp. melongenae Recovered from Eggplant

Fusarium oxysporum (Schlechtend.: Fr.) f. sp. melongenae (Fomg) recovered from symptomatic eggplants from five eggplant‐growing areas in Turkey, including the south, west, north‐west, north and south‐east regions. The objective of this study was to investigate the genetic diversity of the Fomg isolates from different geographical location by pathogenicity and VCG tests. Three hundred and seventy‐four Fomg isolates were classified as highly virulent, virulent, moderately virulent and low virulent through pathogenicity assays. No correlation was observed between virulence of Fomg isolates and their locations. The nitrate non‐utilizing mutants (nit) were generated as nit1, nit3 and NitM, based on phenotyping of Fomg growth characteristics of the Fomg isolates on diagnostic media with various sources of nitrogen. The majority of nit mutants (39.4%) recovered were nit1 from minimal medium (MM) containing of 2.0% potassium chlorate (MMC). The most of Fomg isolates were identified as heterokaryon self‐compatible (HSC) based on their ability to form a stable heterokaryon, while four isolates were classified as heterokaryon self‐incompatible (HSI). A large amount of Fomg isolates were vegetatively compatible and assigned as members of the same VCG, whereas nit mutants of 10 Fomg isolates that did not complement with tester strains only paired by themselves (HSC), these isolates were termed vegetative incompatible (vic). The complementation of 33 isolates with tester strains was slow and quite weak, but not paired with themselves even though they are HSC. About 96.3% of the Fomg isolates were assigned to VCG 0320, while the remaining 3.7% were classified as vegetative incompatible group.     

Molecular characterization of Mycobacterium tuberculosis isolates from Izmir, Turkey

In recent years, molecular typing methods have been used in epidemiologic studies of Mycobacterium tuberculosis isolates in various areas of the world. However, there have been few data on this issue in Turkey. We describe the molecular characterization of 56 Mycobacterium tuberculosis isolates recovered from individual patients in Izmir and the surrounding area by three different molecular methods. Isolated M. tuberculosis strains were characterized by IS6110 RFLP, spoligotyping and major genetic group designation. In total, 51 RFLP and 35 spoligopatterns were identified. Fourteen (25%) isolates were indicated as low copy number. Based on three genotypic characterization methods together, five clusters with two isolates each were identified. Most of the isolates (98.2%) were assigned as genetic groups 2 or 3. Only one isolate was identified as Beijing family strain (principal genetic group 1). The shared international clades were found to be Beijing-family, var T1 (ST 37), LAM (Latin-American-Mediterranean) 7 (ST 41), LAM 9 (ST 42), Haarlem 1 (ST 47), Haarlem 3 (ST 50) and T1 (ST 53). In this study, IS6110 RFLP, spoligotyping and major genetic group designation were found to be useful methods for molecular epidemiologic studies.     

Effect of Dietary Garcinia cambogia Extract on Serum Essential Minerals (Calcium, Phosphorus, Magnesium) and Trace Elements (Iron, Copper, Zinc) in Rats Fed with High-Lipid Diet

The aim of the study was to investigate the effect of Garcinia cambogia extract on serum calcium (Ca), phosphorus (P), magnesium (Mg), iron (Fe), zinc (Zn) and copper (Cu) concentrations in rats fed with the normal or the high-lipid and -cholesterol diet. Thirty 1-year-old female Sprague-Dawley rats (pathogen-free), weighing an average of 229 g, were randomly assigned to three experimental groups of ten animals each. Diets and tap water were given ad libitum for 75 days. Group 1 (control group) was fed with basal diet (2 % liquid vegetable oil, 0 % cholesterol), while the diets of groups 2 and 3 contained vegetable oil (2 % liquid vegetable oil and 5 % hydrogenated vegetable oil) and cholesterol (3 %) in high levels. 4,5 % G. cambogia extract containing 65 % HCA was added to the diet of group 3 as from day 45. Blood samples were withdrawn on days 0, 45 and 75. Serum mineral levels were analyzed using standard enzymatic colorimetric methods with a spectrophotometer. All significant differences were p<0.05. Serum Ca levels were not significantly different between all groups on days 45 and 75. Serum P level was significantly higher in the group fed with high-lipid diet and G. cambogia extract than in the control group on day 45. Serum Mg level was significantly higher in group 2 than in the control group on day 45. Serum Fe levels were significantly lower in the control group than in the other groups on days 45 and 75. Serum Zn level of the group fed with high-lipid diet and G. cambogia extract was significantly higher than in the control group on day 75. Serum Cu levels were significantly higher in group 2 than in the control group, and in group 3 than in group 2 on day 75. In conclusion, a diet containing the high fat amounts may lead to the increase in circular levels of some minerals due to the short-chain fatty acid production lowering the luminal pH which increases mineral solubility, or serving as a fuel for mucosal cells and stimulating cell proliferation in the large intestine. G. cambogia extract may be used in the P and Cu deficiencies due to increases resulting in the present P and Cu amounts in G. cambogia extract, or the use of phytate P in diet. It was hoped that with further evidence-based study this product will enter to mainstream medicines.     

Effect of silymarin on bladder overactivity in cyclophosphamide-induced cystitis rat model

The purpose of this study was to investigate the effects of silymarin, a phytotherapeutic agent, on bladder overactivity in a cyclophosphamide (CYP)-induced cystitis rat model. Female Wistar Albino rats received a single intraperitoneal injection of CYP (150 mg/kg) or saline and after 72 h, bladder function was evaluated by in vitro preparations of whole bladders and cystometry with continuous saline infusion under urethane anesthesia. Silymarin or a vehicle was orally given for 7 days in rats. CYP was injected on the 5th day of silymarin or vehicle treatment and then the animals were killed on the 8th day. CYP-treatment dramatically potentiated the basal spontaneous contractions of isolated whole bladders compared to control rats. In anesthetized rats, during continuous infusion cystometry, intercontraction interval (ICI) was significantly shorter, but bladder voiding pressure was not significantly changed in CYP-injected rats compared to control rats. In the CYP-injected group, silymarin treatment significantly decreased the amplitude, frequency (contractions/min) and area under the curve of spontaneous contractions, but failed to change carbachol-induced contraction in isolated whole bladder. Also, silymarin treatment significantly increased the ICI in comparison to the vehicle treatment. In the saline-injected group, no significant changes in the bladder function were observed between the silymarin and vehicle-treated groups. Histopathological examination showed that CYP-induced bladder inflammation tended to be lower in the silymarin+CYP-treated group. In conclusion, the oral administration of silymarin suppressed CYP-induced bladder overactivity. Silymarin may be considered as an attractive treatment for CYP-induced bladder overactivity.     

Lymphotoxin and lipopolysaccharide induce NF-kappaB-p52 generation by a co-translational mechanism

The 'classical' NF-kappaB activation pathway proceeds via IkappaB kinase (IKK)-beta/gamma-mediated phosphorylation, induced ubiquitination and the degradation of small IkappaBs. An alternative, NF-kappaB-inducing kinase and IKK-alpha-dependent pathway, which stimulates the processing of NF-kappaB2/p100, has recently been suggested. However, no physiological stimulus has been shown to trigger the activation of this pathway. Here we demonstrate that persistent stimulation with lymphotoxin beta (LT-beta) receptor agonists or lipopolysaccharide (LPS), but not with interleukin-1beta, tumour necrosis factor-alpha or 12-O-tetradecanoylphorbol-13-acetate, induces the generation of p52 DNA-binding complexes by activating the processing of the p100 precursor. Induction of p52 DNA-binding activity is delayed in comparison with p50/p65 complexes and depends on de novo protein synthesis. p100 is constitutively and inducibly polyubiquitinated, and both ubiquitination and p52 generation are coupled to continuing p100 translation. Thus, both LT-beta receptor agonists and LPS induce NF-kappaB/p100 processing to p52 at the level of the ribosome.     

Mechanisms of Staphylococcus aureus induced apoptosis of human endothelial cells

Staphylococcus aureus plays an important role in sepsis, pneumonia and wound infections. Here, we demonstrate that infection with several S. aureus strains results in apoptosis of human endothelial cells. S. aureus induced an activation of cellular caspases, the acid sphingomyelinase, a release of cytochrome c and a stimulation of Jun NH₂-terminal kinase (JNK). The significance of these findings is indicated by a prevention of S. aureus triggered apoptosis of human cells deficient for ASM or upon genetic or pharmacological inhibition of JNK or caspases, respectively.     

Asymmetric localization of seed storage protein RNAs to distinct subdomains of the endoplasmic reticulum in developing maize endosperm cells

Plant storage proteins are synthesized and stored in different compartments of the plant endomembrane system. Developing maize seeds synthesize and accumulate prolamin (zein) and 11S globulin (legumin-1) type proteins, which are sequestered in the endoplasmic reticulum (ER) lumen and storage vacuoles, respectively. Immunofluorescence studies showed that the lumenal chaperone BiP was not randomly distributed within the ER in developing maize endosperm but concentrated within the zein-containing protein bodies. Analysis of the spatial distribution of RNAs in maize endosperm sections by in situ RT-PCR showed that, contrary to the conclusions made in an earlier study [Kim et al. (2002) Plant Cell 14: 655-672], the zein and legumin-1 RNAs are not symmetrically distributed on the ER but, instead, targeted to specific ER subdomains. RNAs coding for 22 kDa alpha-zein, 15 kDa beta-zein, 27 kDa gamma-zein and 10 kDa delta-zein were localized to ER-bounded zein protein bodies, whereas 51 kDa legumin-1 RNAs were distributed on adjacent cisternal ER proximal to the zein protein bodies. These results indicate that the maize storage protein RNAs are targeted to specific ER subdomains in developing maize endosperm and that RNA localization may be a prevalent mechanism to sort proteins within plant cells.     

Inhibition of acetylcholine-induced EDHF response by elevated glucose in rat mesenteric artery

The effects of high glucose on endothelium-derived hyperpolarizing factor (EDHF)-mediated relaxations of isolated rat mesenteric artery and the possible involvement of reactive oxygen species in these responses were investigated. After precontraction with phenylephrine (3 x 10(-8)-10(-7) M), acetylcholine (10(-8)-3 x 10(-6) M) and A 23187 (10(-8)-3 x 10(-6) M), a calcium ionophore, induced concentration-dependent relaxations in the presence of N(W)-nitro-l-arginine methyl ester (L-NAME) (10(-4) M) and indomethacin (10(-5) M). These relaxations were abolished in the presence of charybdotoxin (2 x 10(-7) M) plus apamin (10(-7) M) and were assumed to be mediated by EDHF. Effects of elevated glucose were examined by incubating the arterial rings for 6 h in Krebs-Henseleit solution containing 22.2 mM glucose. Under these conditions relaxation to acetylcholine was significantly attenuated but was unchanged when the tissues were incubated for 6 h in solution containing 11.1 mM mannitol used as hyperosmotic control. Addition of superoxide dismutase (SOD) (75 U/ml) and combination of SOD with catalase (200 U/ml) during incubation with high glucose significantly preserved the impairment of EDHF-mediated relaxations to acetylcholine. A 23187-induced endothelium-dependent relaxation was not affected by high glucose. Similarly, relaxations to pinacidil (10(-10)-10(-5) M) and to sodium nitroprusside (SNP) (10(-10)-3 x 10(-7) M) were also unchanged in the rings exposed to high glucose. These results suggest that in rat mesenteric arteries exposed to elevated glucose receptor-dependent EDHF-mediated relaxations (acetylcholine-induced) are impaired whereas receptor-independent ones (A 23187-induced) and responses to smooth muscle relaxants that exert their effects through mechanisms independent of endothelium are unaffected. Our findings lead us to propose that reactive oxygen species like superoxide ((.)O(2)(-)) and hydrogen peroxide (H(2)O(2)) do seem to play a role in the impairment of EDHF-mediated relaxations in the presence of elevated glucose.