Evaluation of accessible regions of Escherichia coli fimH mRNA through computational prediction and experimental investigation

Background and Objectives:

This study aimed to investigate the accessible regions of the fimH mRNA using computational prediction and dot-blot hybridization to increase the effectiveness of antisense anti-virulence therapeutics against Uropathogenic Escherichia coli.

Materials and Methods:

We predicted the secondary structure of the E. coli fimH mRNA using the Sfold and Mfold Web servers and RNA structure 5.5 program. Considering the predicted secondary structure, accessible regions in mRNA of fimH were determined and oligonucleotides complementary to these regions were synthesized and hybridization activity of those oligonucleotides to the fimH Digoxigenin (DIG) labeled mRNA was assessed with dot-blot hybridization.

Results:

When searching the fimH gene in the GenBank database, two lengths for this gene was discovered in different strains of E. coli. The difference was related to the nine bases in the first part of the gene utilizing either of two translation initiation sites. Based on the bioinformatics analyses, five regions lacking obvious stable secondary structures were selected in mRNA of fimH. The result of dot-blot hybridization exhibited strongest hybridization signal between the antisense oligonucleotide number one and fimH labeled mRNA, whereas hybridization signals were not seen for the negative control.

Conclusion:

The results obtained here demonstrate that the region contains start codon of fimH mRNA could act as the potential mRNA target site for anti-fimH antisense therapeutics. It is recommended in the future both of utilizing translation initiation sites be targeted with antisense oligomers compounds.

The relationship between phylogenetic groups and antibiotic susceptibility patterns of Escherichia coli strains isolated from feces and urine of patients with acute or recurrent urinary tract infection

BACKGROUND AND OBJECTIVES

B2 and D have been mentioned as the most common phylogenetic groups among uropathogenic Escherichia coli. However, there is still controversy about the importance of these phylo-groups. This study was conducted to investigate the probable relation between these groups and antibiotic resistance patterns of E. coli isolates derived from urine and feces of the patients with acute or recurrent UTI.

MATERIALS AND METHODS

10 isolates were recovered from urine and feces samples of patients with different phases of UTI in whom E. coli was causative pathogen. Biochemical fingerprinting was performed to classify the isolates and select their appropriate representatives. Phylogenetic grouping was performed using multiplex PCR, and antibiotic resistance was determined by disk diffusion method.

RESULTS

Five-hundred-sixty E. coli isolates were derived from 56 UTI patients (27 acute, 29 recurrent). Among them, 261 isolates were selected using biochemical fingerprinting. All the isolates were sensitive to imipenem and nitrofurantoin. Compared to other phylo-groups, the isolates in group D showed considerably different frequencies in acute vs. recurrent phase of UTI, in urine vs. stool samples, in males vs. females, and in- vs. out-patients. They were more resistant to the antibiotics (except norfloxacin), and in contrast to others, this was seen more in acute UTI, especially in urine samples. Multi-drug resistance pattern was also meaningfully higher in group D.

CONCLUSION

Although phylo-groups B2 and D of E. coli bacteria are more responsible for UTI, group D isolates seem to be more resistant and probably more virulent, even than the ones from group B2.

Leptospirosis in Caspian Sea littoral, Gilan Province, Iran

In Iran, leptospirosis is endemic to Caspian Sea littoral. The disease appears as a seasonal infection mostly affecting people in rural areas involved in farming. We investigated the prevalence of this infection among suspected patients in Gilan Province by an indirect immunofluorescent assay (IFA), and two PCR protocols, a nested-PCR and a real-time PCR (qPCR), targeting rrs and lipL32 genes, respectively. We also identified the common Leptospira species by sequencing a partial sequence of rrs gene. Out of the 128 sera examined by IFA, 25.78% were positive with the antibody titers ≥1/80. The antibody titer in 39.06% of sera ranged from 1/10 to 1/140, and 35. 16% showed no antibodies, all considered negative. Nested PCR and qPCR detected Leptospira DNA in 20.31% and 18.75% of the sera, respectively. The two PCR assays had 98.43% agreement (K = 0.93) and showed an inverse correlation with the IFA titers. Also, three pathogenic Leptospira species, L. kirschneri (n = 10), L. introgans (n = 8), and L. borgpetersenii (n = 2) were identified from the clinical specimens in the study area. In our hands both PCR assays proved very efficient for early diagnosis of illness and could be used in combination with IFA for both diagnosis and epidemiological studies, but nested PCR was cheaper and appeared more appropriate for our laboratories in rural settings.

Adverse effects of BCG vaccine 1173 P2 in Iran: A meta-analysis

Although in the last two decades the World Health Organization (WHO) has introduced tuberculosis as “a threat to global”, the vaccination with the Mycobacterium bovis Bacillus Calmette-Guerin (BCG) is the only way for the prevention of this fatal infectious disease. Despite of the efficacy of BCG vaccine especially against infants’ meningitis, it has still some limitations due to a variety of adverse effects. Many studies have evaluated the side effects of different strains of BCG vaccines in different countries. In Iran, some studies have been done so far to evaluate the adverse effects of 1173 P2 strain which is used for BCG vaccination. Each of these studies have used different standardization and sampling methods. This review will survey all studies that have been published about adverse effects of 1173 P2 strain of BCG vaccine in Iran using data mining methods.

Abstract 2538: The anti-proliferative effect of PUVA treatment on human bladder cancer cell lines

Introduction and Objectives: Although immunotherapy and chemotherapy are the most used intravesical treatments for non-muscle-invasive bladder cancer (NMIBC), progression and recurrence rates are high. So far, several attempts have been done to hire a safer and more efficient treatment.

Psoralen (a photoreactive chemical substance) metabolites followed by Ultra Violet A (UVA) irradiation (PUVA therapy) have been previously used to treat a variety of diseases. UVA radiation forms covalent bonds between psoralen molecule and pyrimidine bases of DNA to create interstrand cross-links, which blocks DNA replication, thereby inhibiting cell proliferation. In addition, PUVA therapy leads to apoptosis and local immune reaction.

The aim of this study was to evaluate the anti-proliferative effects of PUVA treatment on human bladder cancer cell lines as the first step of further investigations, in order to consider it as a new candidate for NMIBC treatment.

Material and Methods: Human bladder cancer cell lines (T24, grade III and RT4, grade I) were cultured in vitro, treated with 500 ng/ml 8-methoxypsoralen (8-MOP, a natural psoralen metabolite) and incubated in the dark room for 45 minutes. Cells were then irradiated with UVA (365 nm) at different doses (0, 0.5, 2 and 5 J/cm2).

After 24- or 48-hour PUVA treatment, cells were counted to measure cell growth. MTT assay was performed in order to analyze cell viability and BrdU incorporation assay to evaluate the anti-proliferative effect of PUVA treatment. Cells were also stained with Annexin V-FITC and observed under fluorescence microscope in order to measure the amount of apoptotic cells.

Results: Both T24 and RT4 cells treated with 2 and 5 J/cm2 UVA showed a significant decrease (P < 0.05) in the amount of cells after 24 hours, as compared to no UVA-treated cells. After 48 hours of PUVA treatment with all the three doses of UVA, the number of cells was significantly decreased in both cell lines.

In MTT assay, PUVA-treated RT4 cells significantly reduced viability with 0.5, 2 and 5 J/cm2 UVA-treatments, as compared to no UVA-treatment. Differently, T24 cells showed a significant reduction of viability with only 5 J/cm2 UVA treatment.

BrdU incorporation assay in both cell lines revealed a significant reduction of cell proliferation after PUVA treatment with all the three different UVA doses in comparison to no UVA treatment.

Fluorescent microscopic observation of cell lines stained using Annexin V-FITC showed an increased number of apoptotic cells among those particularly treated with 2 and 5 J/cm2 UVA doses, as compared to no UVA-treated cells.

Conclusions: PUVA treatment, mostly at higher UVA doses, has a significant anti-proliferative effect on human bladder cancer cell lines by inhibiting cell growth, reducing cell viability and inducing apoptosis. These results suggest a possible relevant use of PUVA therapy for the treatment of NMIBC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2538. doi:10.1158/1538-7445.AM2011-2538

Is inflammation a consequence of extracellular hyperosmolarity?

Background

There are several reports suggesting that hyperosmolarity induces inflammation. We recently showed that Dextran Sodium Sulfate causes inflammatory bowel disease due to hyperosmolarity. The aim of this study was to confirm the link between hyperosmolarity and inflammation by assessing osmolarity values in vivo during inflammation, compare the inflammatory potential of different osmotic agents and finally study the long-term consequences of hyperosmolarity on cell fate.

Methods

Osmotic pressures were measured in inflammatory liquids withdrawn from mice subjected to inflammation caused either by subcutaneous injection of Bacille Calmette-Guérin (BCG) or Freund adjuvant. Three epithelial cell lines (HT29, T24 and A549) were exposed up to 48 hours to increasing osmolarities (300, 600, 900 mOsm) of chemically inert molecules such as Mannitol, Propylene Glycol, and Glycerol and inflammatory response was assessed by Enzyme Linked ImmunoSorbent Assay (ELISA) and RNA Protection Assay (RPA). Finally, normal mouse macrophages were exposed to hyperosmotic conditions for long-term culture.

Results

The inflammation caused either by BCG or Freund adjuvant is correlated to hyperosmolarity in inflammatory liquids. The exposure of cells to the different compounds, whatever their molecular weight, has no effect on the secretion of cytokines as long as the osmolarity is below a threshold of 300 mOsm. Higher osmolarities result in the secretion of proinflammatory cytokines (Interleukin-8, Interleukin-6, Interleukin-1β and Tumor Necrosis factor-α). Long-term hyperosmotic culture extends normal macrophage half-life, from 44 days to 102 days, and alters the expression of p53, Bcl-2 and Bax.

Conclusion

The present study further suggests inflammation and hyperosmolarity are closely related phenomena if not synonymous.

Hyperosmotic stress contributes to mouse colonic inflammation through the methylation of protein phosphatase 2A

There are several reports suggesting hyperosmotic contents in the feces of patients suffering from inflammatory bowel disease (IBD). Previous works have documented that hyperosmolarity can cause inflammation attributable to methylation of the catalytic subunit of protein phosphatase 2A (PP2A) and subsequent NF-kappaB activation resulting in cytokine secretion. In this study, we demonstrate that dextran sulfate sodium (DSS) induces colitis due to hyperosmolarity and subsequent PP2A activation. Mice were randomized and fed with increased concentrations of DSS (0 mOsm, 175 mOsm, 300 mOsm, and 627 mOsm) for a duration of 3 wk or with hyperosmotic concentrations of DSS (627 mOsm) or mannitol (450 mOsm) for a duration of 12 wk. Long-term oral administration of hyposmotic DSS or mannitol had no demonstrable effect. Hyperosmotic DSS or mannitol produced a significant increase in colonic inflammation, as well as an increase in the weight of sacral lymph nodes and in serum amyloid A protein levels. Similar results were obtained through the ingestion of comparable osmolarities of mannitol. Hyperosmolarity induces the methylation of PP2A, nuclear p65 NF-kappaB activation. and cytokine secretion. The rectal instillation of okadaic acid, a well-known PP2A inhibitor, reverses the IBD. Short inhibiting RNAs (siRNAs) targeted toward PP2Ac reverse the effect of hyperosmotic DSS. The present study strongly suggests that DSS-induced chronic colitis is a consequence of the methylation of PP2Ac induced by hyperosmolarity.