Regulation of ssb Gene Expression in Escherichia coli

Bacterial SSB proteins, as well as their eukaryotic RPA analogues, are essential and ubiquitous. They avidly bind single-stranded DNA and regulate/coordinate its metabolism, hence enabling essential DNA processes such as replication, transcription, and repair. The prototypic Escherichia coli SSB protein is encoded by an ssb gene. Although the ssb gene promoters harbor an SOS box, multiple studies over several decades failed to elucidate whether ssb gene expression is inducible and SOS dependent. The SOS regulon is comprised of about 50 genes, whose transcription is coordinately induced under stress conditions. Using quantitative real-time PCR, we determined the ssb gene expression kinetics in UV- and γ-irradiated E. coli and revealed that ssb gene expression is elevated in irradiated cells in an SOS-dependent manner. Additionally, the expression of the sulA gene was determined to indicate the extent of SOS induction. In a mutant with a constitutively induced SOS regulon, the ssb gene was overexpressed in the absence of DNA damage. Furthermore, we measured ssb gene expression by droplet digital PCR during unaffected bacterial growth and revealed that ssb gene expression was equal in wild-type and SOS- bacteria, whereas sulA expression was higher in the former. This study thus reveals a complex pattern of ssb gene expression, which under stress conditions depends on the SOS regulon, whereas during normal bacterial growth it is unlinked to SOS induction. The E. coli ssb gene is SOS regulated in such a way that its basal expression is relatively high and can be increased only through stronger SOS induction. The remarkable SOS induction observed in undisturbed wild-type cells may challenge our notion of the physiological role of the SOS response in bacteria.

Long noncoding RNA HOTTIP/HOXA13 expression is associated with disease progression and predicts outcome in hepatocellular carcinoma patients.

UNLABELLED: Hepatocellular carcinoma (HCC) is among the leading causes of cancer-related death. Despite the advances in diagnosis and management of HCC, the biology of this tumor remains poorly understood. Recent evidence highlighted long noncoding RNAs (lncRNAs) as crucial determinants of HCC development. In this study we report the lncRNA HOXA transcript at the distal tip (HOTTIP) as significantly up-regulated in HCC specimens. The HOTTIP gene is located in physical contiguity with HOXA13 and directly controls the HOXA locus gene expression by way of interaction with the WDR5/MLL complex. HOX genes encode transcription factors regulating embryonic development and cell fate. We previously described HOX genes deregulation to be involved in hepatocarcinogenesis. Indeed, we observed the marked up-regulation of HOXA13 in HCC. Here, by correlating clinicopathological and expression data, we demonstrate that the levels of HOTTIP and HOXA13 are associated with HCC patients' clinical progression and predict disease outcome. In contrast to the majority of similar studies, our data were obtained from snap-frozen needle HCC biopsies (n=52) matched with their nonneoplastic counterparts collected from patients who had not yet received any HCC-tailored therapeutic treatments at the time of biopsy. In addition, taking advantage of gain and loss of function experiments in liver cancer-derived cell lines (HuH-6 and HuH-7), we uncover a novel bidirectional regulatory loop between HOTTIP/HOXA13. CONCLUSION: Our study highlights the key role of HOTTIP and HOXA13 in HCC development by associating their expression with metastasis and survival in HCC patients, provides novel insights on the function of lncRNA-driven hepatocarcinogenesis, and paves the way for further investigation about the possible role of HOTTIP as a predictive biomarker of HCC.

Overexpression of Prox-1 gene in omental adipose tissue and adipocytes compared with subcutaneous adipose tissue and adipocytes in healthy patients.

Adipogenesis is the biological process that controls the development of adipocytes, and is one of the most well studied models of cellular differentiation. In the last decade the study of regulation of human adipogenesis was useful to understand this process, in order to reduce disease such as obesity and diabetes. Prox1 is a transcription factor related to Drosophila Prospero homeobox gene, that plays a major role in the development of central nervous system, liver and pancreas. Prox1 is one of the genes that control the embryonic development and differentiation of the lymphatic system. In this study we decided to analyze the gene expression of Prox-1 in fragments of human adipose tissue (subcutaneous and omental) and in human adipocytes isolated from omental and subcutaneous tissue. Our results show Prox-1 is always expressed in adipose tissue and overexpressed in omental adipocytes compared with subcutaneous adipocytes. These preliminary observations confirm a strong correlation of blood vessel development and adipogenesis.

The HOX genes network in metabolic diseases.

Fat distribution is associated with metabolic risk. Differences in cellular characteristics and metabolic functions of these depots have been described, but the molecular mechanisms involved are not understood. The pathogenesis and pathophysiology of metabolic disease can be better understood by studying the molecular mechanisms that control the development and function of adipose tissue (adipogenesis). Homeobox genes are transcription factors that act during normal development and contain the homeobox, a 183bp DNA sequence coding for a 61 amino acid domain defined as homeodomain (HD). Class 1 homeobox genes (Hox genes) have a critical role in controlling positional information and tissue patterning during development. The expression of the whole HOX gene network in different deposits of normal adult human white adipose tissue (intraperitoneal, extra-peritoneal and dermis) indicate a marked expression in adipose tissue. Furthermore, this expression seems to vary in different bodily deposits of white adipose tissue and between white and brown adipose tissue. The purpose of this mini-review is to discuss the role of HOX genes in metabolic diseases.

Reverse transcription-quantitative PCR (RT-qPCR) without the need for prior removal of DNA.

The procedure illustrated in this paper represents a new method for transcriptome analysis by PCR (Polymerase Chain Reaction), which circumvents the need for elimination of potential DNA contamination. Compared to the existing methodologies, our method is more precise, simpler and more reproducible because it preserves the RNA's integrity, does not require materials and/or reagents that are used for elimination of DNA and it also reduces the number of samples that should be set up as negative controls. This novel procedure involves the use of a specifically modified primer during reverse transcription step, which contains mismatched bases, thus producing cDNA molecules that differ from genomic DNA. By using the same modified primer in PCR amplification, only cDNA template is amplified since genomic DNA template is partially heterologous to the primer. In this way, amplification by PCR is unaffected by any potential DNA contamination since it is specific only for the cDNA template. Furthermore, it accurately reflects the initial RNA concentration of the sample, which is prone to changes due to various physical or enzymatic treatments commonly used by the current methodologies for DNA elimination. The method is particularly suitable for quantification of highly repetitive DNA transcripts, such as satellite DNA.

Potential Role of Natural Antioxidant Products in Oncological Diseases.

Nutrition has a significant effect and a crucial role in disease prevention. Low consumption of fruit and vegetables and a sedentary lifestyle are closely related with the onset and development of many types of cancer. Recently, nutraceuticals have gained much attention in cancer research due to their pleiotropic effects and relatively non-toxic behavior. In fact, although in the past there have been conflicting results on the role of some antioxidant compounds as allies against cancer, numerous recent clinical studies highlight the efficacy of dietary phytochemicals in the prevention and treatment of cancer. However, further investigation is necessary to gain a deeper understanding of the potential anticancer capacities of dietary phytochemicals as well as the mechanisms of their action. Therefore, this review examined the current literature on the key properties of the bioactive components present in the diet, such as carotenoids, polyphenols, and antioxidant compounds, as well as their use in cancer therapy. The review focused on potential chemopreventive properties, evaluating their synergistic effects with anticancer drugs and, consequently, the side effects associated with current cancer treatments.

Human mature adipocytes express albumin and this expression is not regulated by inflammation.

AIMS: Our group investigated albumin gene expression in human adipocytes, its regulation by inflammation and the possible contribution of adipose tissue to albumin circulating levels. METHODS: Both inflamed and healthy subjects provided adipose tissue samples. RT-PCR, Real-Time PCR, and Western Blot analysis on homogenates of adipocytes and pre-adipocytes were performed. In sixty-three healthy subjects and fifty-four micro-inflamed end stage renal disease (ESRD) patients circulating levels of albumin were measured by nephelometry; all subjects were also evaluated for body composition, calculated from bioelectrical measurements and an thropometric data. RESULTS: A clear gene expression of albumin was showed in pre-adipocytes and, for the first time, in mature adipocytes. Albumin gene expression resulted significantly higher in pre-adipocytes than in adipocytes. No significant difference in albumin gene expression was showed between healthy controls and inflamed patients. A significant negative correlation was observed between albumin levels and fat mass in both healthy subjects and inflamed ESRD patients. CONCLUSIONS: In the present study we found first time evidence that human adipocytes express albumin. Our results also showed that systemic inflammation does not modulate albumin gene expression. The negative correlation between albumin and fat mass seems to exclude a significant contributing role of adipocyte in plasma albumin.

Deregulated HOX genes in ameloblastomas are located in physical contiguity to keratin genes.

The expression of the HOX gene network in mid-stage human tooth development mostly concerns the epithelial tooth germ compartment and involves the C and D HOX loci. To further dissect the HOX gene implication with tooth epithelium differentiation we compared the expression of the whole HOX network in human ameloblastomas, as paradigm of epithelial odontogenic tumors, with tooth germs. We identified two ameloblastoma molecular types with respectively low and high number of active HOX C genes. The highly expressing HOX C gene ameloblastomas were characterized by a strong keratinized phenotype. Locus C HOX genes are located on chromosome 12q13-15 in physical contiguity with one of the two keratin gene clusters included in the human genome. The most posterior HOX C gene, HOX C13, is capable to interact with hair keratin genes located on the other keratin gene cluster in physical contiguity with the HOX B locus on chromosome 17q21-22. Inside the HOX C locus, a 2.2 kb ncRNA (HOTAIR) able to repress transcription, in cis, along the entire HOX C locus and, in trans, at the posterior region of the HOX D locus has recently been identified. Interestingly both loci are deregulated in ameloblastomas. Our finding support an important role of the HOX network in characterizing the epithelial tooth compartment. Furthermore, the physical contiguity between locus C HOX and keratin genes in normal tooth epithelium and their deregulation in the neoplastic counterparts suggest they may act on the same mechanism potentially involved with epithelial tumorigenesis.

Expression of lumbosacral HOX genes, crucial in kidney organogenesis, is systematically deregulated in clear cell kidney cancers.

Homeobox-containing genes are involved in different stages of kidney organogenesis, from the early events in intermediate mesoderm to terminal differentiation of glomerular and tubular epithelia. The HOX genes show a unique genomic network organization and regulate normal development. The targeted disruption of paralogous group 11 HOX genes (HOX A11, HOX C11 and HOX D11) results in a complete loss of metanephric kidney induction. Despite a large amount of data are related to the early events in the kidney development, not much is known about HOX genes in advanced kidney organogenesis and carcinogenesis. Here, we compare the expression of the whole HOX gene network in late-stage human foetal kidney development with the same patterns detected in 25 pairs of normal clear cell renal carcinomas (RCCs) and 15 isolated RCC biopsy samples. In the majority of RCCs tested, HOX C11 is upregulated, whereas HOX D11, after an early involvement becomes active again at the 23rd week of the foetal kidney development, is always expressed in normal adult kidneys and is deregulated, together with HOX A11 and lumbosacral locus D HOX genes. Thus, through its function of regulating phenotype cell identity, the HOX network plays an important role in kidney carcinogenesis. Lumbosacral HOX genes are involved in the molecular alterations associated with clear cell kidney cancers and represent, through their deregulation, a molecular mark of tubular epithelial dedifferentiation occurring along tumour evolution, with the restoration of genetic programs associated with kidney organogenesis. The deregulation of lumbosacral HOX genes in RCCs supports (i) the consideration of the HOX gene transcriptome as the potential prognostic tool in kidney carcinogenesis and (ii) the possibility to foresee clinical trials with the purpose of targeting these genes to achieve a therapeutic effect in RCC patients.

A translational approach to micro-inflammation in end-stage renal disease: molecular effects of low levels of interleukin-6.

Inflammation plays a key role in the progression of cardiovascular disease, the leading cause of mortality in ESRD (end-stage renal disease). Over recent years, inflammation has been greatly reduced with treatment, but mortality remains high. The aim of the present study was to assess whether low (<2 pg/ml) circulating levels of IL-6 (interleukin-6) are necessary and sufficient to activate the transcription factor STAT3 (signal transducer and activator of transcription 3) in human hepatocytes, and if this micro-inflammatory state was associated with changes in gene expression of some acute-phase proteins involved in cardiovascular mortality in ESRD. Human hepatocytes were treated for 24 h in the presence and absence of serum fractions from ESRD patients and healthy subjects with different concentrations of IL-6. The specific role of the cytokine was also evaluated by cell experiments with serum containing blocked IL-6. Furthermore, a comparison of the effects of IL-6 from patient serum and rIL-6 (recombinant IL-6) at increasing concentrations was performed. Confocal microscopy and Western blotting demonstrated that STAT3 activation was associated with IL-6 cell-membrane-bound receptor overexpression only in hepatocytes cultured with 1.8 pg/ml serum IL-6. A linear activation of STAT3 and IL-6 receptor expression was also observed after incubation with rIL-6. Treatment of hepatocytes with 1.8 pg/ml serum IL-6 was also associated with a 31.6-fold up-regulation of hepcidin gene expression and a 8.9-fold down-regulation of fetuin-A gene expression. In conclusion, these results demonstrated that low (<2 pg/ml) circulating levels of IL-6, as present in non-inflamed ESRD patients, are sufficient to activate some inflammatory pathways and can differentially regulate hepcidin and fetuin-A gene expression.

The pulmonary-proteoliposome as a new therapeutic approach for Coronaviruses.

We are proposing the use of pulmonary-proteoliposome as a new therapeutic approach for Coronaviruses. The designed strategy represents a potential treatment to reduce the overall viral load in the lungs and to help the immune system to successfully stave off the infection.

Serum fetuin a in hemodialysis: a link between derangement of calcium-phosphorus homeostasis and progression of atherosclerosis?

BACKGROUND: Fetuin A, a circulating inhibitor of ectopic calcification, is downregulated in hemodialysis and has been shown to predict cardiovascular mortality in this setting. The association of altered calcium-phosphorus with serum fetuin A levels is still a matter of debate. Although carotid intima-media thickness (cIMT) is a strong predictor of major cardiovascular events, its association with serum fetuin A levels is poorly defined. STUDY DESIGN: Cohort study. PARTICIPANTS & SETTINGS: 174 uremic patients on long-term hemodialysis therapy enrolled in 4 university hospitals. PREDICTORS: Serum fetuin A levels at the beginning of the study (T0) and after 12 months (T12). OUTCOMES: Progression of atherosclerosis assessed by means of cIMT measurements at 24 months (T24); cardiovascular morbidity and mortality at 36 months. RESULTS: Serum fetuin A concentrations at T0 and T12 were 282.3 +/- 79.4 and 290.0 +/- 92.2 microg/mL, respectively. Mean T0 and T24 cIMT values were 1.02 +/- 0.2 and 1.06 +/- 0.2 mm, respectively (P < 0.001). Fatal and nonfatal cardiovascular disease occurred in 36 and 86 patients by 36 months, respectively. In multivariate logistic regression, higher calcium-phosphorus product was associated with lower serum fetuin A level (odds ratio, 0.96; 95% confidence interval [CI], 0.93 to 1.00; P = 0.02). Multiple regression analysis showed that T0 serum fetuin A level was associated with T24 cIMT (P = 0.01) after adjustments for age, cholesterol level, high-sensitivity C-reactive protein level, previous cardiovascular events, and T0 cIMT. In a multivariate Cox regression analysis, cardiovascular mortality was independently associated with a 1-tertile lower T0 serum fetuin A level, and a 1-tertile higher T0 cIMT value was independently associated with greater cardiovascular mortality (hazard ratio, 0.45; 95% CI, 0.15 to 0.65; P = 0.007 and hazard ratio, 10.00; 95% CI, 3.16 to 31.73; P < 0.001, respectively) after adjustment for age and previous cardiovascular events. LIMITATION: Length of follow-up. CONCLUSION: Calcium-phosphorus product in hemodialysis patients inversely correlated with serum fetuin A level, which, in turn, was associated inversely with progression of atherosclerotic lesions and cardiovascular mortality in this study population.

Effects of various prophylactic procedures on titanium surfaces and biofilm formation.

PURPOSE: The aim of this study was to evaluate the effects of various prophylactic treatments of titanium implants on bacterial biofilm formation, correlating surface modifications with the biofilms produced by Pseudomonas aeruginosa PAO1, Staphylococcus aureus, and bacteria isolated from saliva. METHODS: Pure titanium disks were treated with various prophylactic procedures, and atomic force microscopy (AFM) was used to determine the degree to which surface roughness was modified. To evaluate antibiofilm activity, we used P. aeruginosa PAO1, S. aureus, and saliva-isolated Streptococcus spp., Bacteroides fragilis, and Staphylococcus epidermidis. RESULTS: AFM showed that the surface roughness increased after using the air-polishing device and ultrasonic scaler, while a significant reduction was observed after using a curette or polishing with Detartrine ZTM (DZ) abrasive paste. In addition, we only observed a significant (P<0.01) reduction in biofilm formation on the DZ-treated implant surfaces. CONCLUSION: In this study, both AFM and antibiofilm analyses indicated that using DZ abrasive paste could be considered as the prophylactic procedure of choice for managing peri-implant lesions and for therapy-resistant cases of periodontitis.

Fetuin-A gene expression, synthesis and release in primary human hepatocytes cultured in a galactosylated membrane bioreactor.

This paper reports on human hepatocytes cultured in a galactosylated membrane bioreactor in order to explore the modulation of the effects of a pro-inflammatory cytokine, Interleukin-6 (IL-6) on the liver cells at molecular level. In particular the role of IL-6 on gene expression and production of a glycoprotein, fetuin-A produced by hepatocytes, was investigated by culturing hepatocytes in the membrane bioreactor, both in the absence and presence of IL-6 (300 pg/ml). IL-6 modulated the fetuin-A gene expression, synthesis and release by primary human hepatocytes cultured in the bioreactor. A 75% IL-6-induced reduction of fetuin-A concentration in the medium was associated with a 60% increase of C-reactive protein in the same samples. Real-time-PCR demonstrated an 8-fold IL-6-induced reduction of fetuin-A gene expression. These results demonstrate that the hepatocyte galactosylated membrane bioreactor is a valuable tool to study IL-6 effects and gave evidence, for the first time, that IL-6 down-regulates the gene expression and synthesis of fetuin-A by primary human hepatocytes. The human hepatocyte bioreactor behaves like the in vivo liver, reproducing the same hepatic acute-phase response that occurs during the inflammatory process.

Polyacrylic resins regulate transcriptional control of interleukin-6, gp80, and gp130 genes in human gingival fibroblasts.

Studies have failed to identify the molecular mechanisms that regulate the genotoxic and cytotoxic effects of methacrylate resins, which are important in the biocompatibility of dental materials. Interleukin (IL)-6 has a crucial role in the control of acute-phase protein response during inflammation. In humans, the synthesis and release of two major acute-phase proteins, C-reactive protein and serum amyloid A, are regulated by IL-6. This study focused on IL-6 and activation of its receptors gp80 and gp130 in human gingival fibroblasts in order to assess the effects of the commercial acid resins Jet Kit, Unifast, and Duralay on control of inflammation.

Radiocontrast media cause dephosphorylation of Akt and downstream signaling targets in human renal proximal tubular cells.

Radiocontrast medium induced nephrotoxicity is a major clinical problem. There is considerable interest in reducing the incidence of acute renal failure due to the use of radiocontrast media (RCM). Reduction of renal blood flow and direct toxic effect on renal tubular epithelial cells have been postulated as major causes of RCM nephropathy. Understanding the molecular mechanisms by which RCM cause cell damage may allow the development of pharmacological therapy to prevent their nephrotoxicity. In this work we have investigated the signaling pathways that may be affected by RCM. The incubation of human renal tubular proximal cells with sodium diatrizoate, iopromide and iomeprol caused a marked dephosphorylation of the kinase Akt on Ser473 within 5min of incubation. RCM also caused a decrease in cell viability, which was substantially alleviated by transfecting the cells with a constitutively active form of Akt. Further downstream targets of Akt, including the Forkhead family of transcription factors FKHR and FKHRL1, were also dephosphorylated by RCM at Thr24 and Thr32, respectively. The P70S6 kinase was also dephosphorylated at Thr389 and Ser371 by RCM. However there was a more dramatic decrease in phosphorylation of the phosphorylated form of mammalian target of rapamycin (mTOR) and of the extracellular-signal regulated kinases (ERK) 1/2 caused by sodium diatrizoate than by iopromide. These results demonstrate the effect of RCM on some intracellular signaling pathways that may allow understanding of the mechanism of their toxicity and may allow the development of strategies to overcome their adverse effects.

Long-term maintenance of human hepatocytes in oxygen-permeable membrane bioreactor.

An oxygen-permeable membrane bioreactor utilizing human hepatocytes has been tested in this study. In the bioreactor, human hepatocytes were cultured between flat-sheet gas-permeable polymeric membranes, which ensure the diffusion of O(2) and CO(2) providing a support for cell anchorage and growth and permit the online observation of the cells with an inverse microscope. This bioreactor allows a direct oxygenation of cells adhered on membranes and of the medium overlaying cells simulating in vivo sinusoidal organization. Human hepatocytes were cultured in the presence of some therapeutic molecules to assess the temporal liver-specific functions of the cells. Interleukin 6 (IL-6), which is a multifactorial proinflammatory cytokine involved in a variety of host defences and pathological processes, and diclofenac, an arylacetic non-steroidal anti-inflammatory drug, were used as therapeutic molecules. The aim of this study was to evaluate the in vitro performance of the small oxygen-permeable membrane bioreactor in the long-term maintenance and differentiation of human hepatocytes under in-vivo-like conditions. The fluid dynamics of the bioreactor were characterized before using it for human cell culture. The functional response to a step challenge in the medium of IL-6 (120 pg/ml), diclofenac (80 microm) and IL-6 and diclofenac together was investigated. The ability of hepatocytes to perform liver-specific functions in terms of urea and albumin synthesis, as well as secretion of total proteins, was maintained for 32 days. Also, the diclofenac biotransformation functions were sustained as the formation of the metabolites 4'-OH-diclofenac and 5-OH-diclofenac lactam demonstrated. This study attested the feasibility of the membrane bioreactor as an in vitro simple model system that allows human hepatocytes to be maintained in a differentiated state similar to that in vivo.

Class I Homeobox Genes, "The Rosetta Stone of the Cell Biology", in the Regulation of Cardiovascular Development.

Class I homeobox genes (Hox in mice and HOX in humans), encode for 39 transcription factors and display a unique genomic network organization mainly involved in the regulation of embryonic development and in the cell memory program. The HOX network controls the aberrant epigenetic modifications involving in the cell memory program. In details, the HOX cluster plays a crucial role in the generation and evolution of several diseases: congenic malformation, oncogenesis, metabolic processes and deregulation of cell cycle. In this review, I discussed about the role of HOX gene network in the control of cardiovascular development.

The role of interleukin-6 and of its soluble receptors in the biocompatibility of dialysis treatment.

Proinflammatory cytokines, in addition to their role in host defence, may be considered mediators of disease; a reduction of cytokine synthesis or effects is, therefore, becoming a target of many diseases. IL-6 is a pro-inflammatory cytokine that may play a role in several clinical problems related to dialysis treatment. An enhanced spontaneous production of IL-6 by Peripheral Blood Mononuclear Cells (PBMC) harvested from ESRD patients dialyzed with a poor biocompatible membrane has been first demonstrated by our group. These results were also obtained in patients undergoing continuous peritoneal dialysis, in absence of peritonitis. We have also demonstrated that IL-6 release was inversely correlated with serum albumin changes. Biological activities of IL-6 may be modulated by two soluble circulating receptors, namely sIL-6R and sgp130. sIL-6R may enhance the inflammatory effects of IL-6 and is, therefore, an "agonistically" acting molecule. We have recently studied sIL-6R production in ESRD patients dialyzed with different membranes; the conclusion was that poor biocompatible membranes, via the sIL-6R, might further increase the inflammatory effects of IL-6. On the contrary, sgp130 can efficiently bind the IL-6/sIL-6R complex with "antagonistic" effects. We have evaluated plasma levels of sgp130 in 18 ESRD patients regularly dialyzed with hemophan membranes (HE) and in 15 patients dialyzed with more biocompatible synthetic membranes (BIO). Our results demonstrate that plasma levels of sgp130 in HE are 33% higher than in both healthy controls and BIO. Circulating levels of sgp130 were correlated positively with C-reactive protein (r: 0.338, p<0.05) and negatively with serum albumin (r: -0.334, p<0.05). These results suggest that higher circulating levels of sgp130 are likely associated with higher IL-6 levels. These higher amounts are probably insufficient to control the activity of IL-6 and may be considered only as a marker of PBMC activation.