Extensive genomic diversity and selective conservation of virulence determinants in enterohemorrhagic Escherichia coli strains of O157 and non O157 serotypes

Background: Enterohemorrhagic Escherichia coli (EHEC) O157 causes severe food-borne illness in humans. The chromosome of O157 consists of 4.1 Mb backbone sequences shared by benign E. coli K-12, and 1.4 Mb O157-specific sequences encoding many virulence determinants, such as Shiga toxin genes (stx genes) and the locus of enterocyte effacement (LEE). Non-O157 EHECs belonging to distinct clonal lineages from O157 also cause similar illness in humans. According to the "parallel" evolution model, they have independently acquired the major virulence determinants, the stx genes and LEE. However, the genomic differences between O157 and non-O157 EHECs have not yet been systematically analyzed. Results: Using microarray and whole genome PCR scanning analyses, we performed a whole genome comparison of 20 EHEC strains of O26, O111, and O103 serotypes with O157. In non-O157 EHEC strains, although genome sizes were similar with or rather larger than O157 and the backbone regions were well conserved, O157-specific regions were very poorly conserved. Around only 20% of the O157- specific genes were fully conserved in each non-O157 serotype. However, the non-O157 EHECs contained a significant number of virulence genes that are found on prophages and plasmids in O157, and also multiple prophages similar to, but significantly divergent from, those in O157. Conclusion: Although O157 and non-O157 EHECs have independently acquired a huge amount of serotype- or strain-specific genes by lateral gene transfer, they share an unexpectedly large number of virulence genes. Independent infections of similar but distinct bacteriophages carrying these virulence determinants are deeply involved in the evolution of O157 and non-O157 EHECs

Risk for the occupational infection by cytomegalovirus among health-care workers

Background Cytomegalovirus (CMV) are ubiquitously distributed worldwide, causing a wide range of clinical manifestations from congenital infection to a life-threatening disease in immunocompromised individuals. CMV can be transmitted via human-to-human contact through body fluids; however, the risk of CMV infection among healthcare workers (HCWs) has not been fully evaluated. Aim This study aimed to assess the risk of CMV infection among HCWs through daily medical practices. Methods Serum samples from HCWs at Osaka University Hospital (Japan) were analysed. Initially, we compared CMV IgG seropositivity among HCWs (medical doctors, nurses, and others) in 2017, which was examined after 1 year to evaluate seroconversion rates among those with seronegative results. Then, we examined CMV seroconversion rates in HCWs who were exposed to blood and body fluids. Findings We analysed 1153 samples of HCWs (386 medical doctors, 468 nurses, and 299 others), of which CMV seropositivity rates were not significantly different (68.9%, 70.3%, and 70.9%, respectively). Of these, 63.9% (221/346) of CMV seronegative HCWs were followed after 1 year, with CMV seroconversion rates of 3.2% (7/221). Among 72 HCWs who tested negative for CMV IgG when exposed to blood and body fluids, the CMV seroconversion rate was 2.8% (2/72). The CMV seroconversion rates between the two situations were not significantly different. Conclusion Our study indicated that CMV infection through daily patient care seems quite rare. Further well-designed studies with a large sample size are warranted to verify our finding

Insulin receptor substrate-2 maintains predominance of anabolic function over catabolic function of osteoblasts

Insulin receptor substrates (IRS-1 and IRS-2) are essential for intracellular signaling by insulin and insulin-like growth factor-I (IGF-I), anabolic regulators of bone metabolism. Although mice lacking the IRS-2 gene (IRS-2−/− mice) developed normally, they exhibited osteopenia with decreased bone formation and increased bone resorption. Cultured IRS-2−/− osteoblasts showed reduced differentiation and matrix synthesis compared with wild-type osteoblasts. However, they showed increased receptor activator of nuclear factor κB ligand (RANKL) expression and osteoclastogenesis in the coculture with bone marrow cells, which were restored by reintroduction of IRS-2 using an adenovirus vector. Although IRS-2 was expressed and phosphorylated by insulin and IGF-I in both osteoblasts and osteoclastic cells, cultures in the absence of osteoblasts revealed that intrinsic IRS-2 signaling in osteoclastic cells was not important for their differentiation, function, or survival. It is concluded that IRS-2 deficiency in osteoblasts causes osteopenia through impaired anabolic function and enhanced supporting ability of osteoclastogenesis. We propose that IRS-2 is needed to maintain the predominance of bone formation over bone resorption, whereas IRS-1 maintains bone turnover, as we previously reported; the integration of these two signalings causes a potent bone anabolic action by insulin and IGF-I

Elevated levels of plasma lactate dehydrogenase is an unfavorable prognostic factor in patients with epidermal growth factor receptor mutation-positive non-small cell lung cancer, receiving treatment with gefitinib or erlotinib.

Treatment with epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) has been shown to prolong survival in patients with EGFR mutation-positive non-small cell lung cancer (NSCLC). The present study performed a retrospective analysis to investigate the association between the plasma lactate dehydrogenase (LDH) levels and survival in patients with EGFR mutation-positive NSCLC receiving treatment with EGFR-TKIs. The medical charts of patients with EGFR mutation-positive NSCLC who were receiving treatment with EGFR-TKIs at Toyama University Hospital between 2007 and 2014 were assessed. The data from 65 patients were included in the analysis. Patients with higher plasma LDH levels exhibited shorter progression-free survival (6.2 vs. 13.2 months; P<0.01) and overall survival (10.5 vs. 36.1 months; P<0.01) periods compared with patients with lower plasma LDH levels. A Cox proportional hazards model identified that the plasma LDH level was associated with the progression-free survival (P=0.05) and overall survival (P<0.01). An association was demonstrated between the pretreatment plasma LDH level and the survival in patients with EGFR mutation-positive NSCLC receiving treatment with EGFR-TKIs. Close observation is required in EGFR mutation-positive NSCLC patients exhibiting high plasma LDH levels following the initiation of treatment with EGFR-TKIs.出版社サイトへのリンク：https://doi.org/10.3892/mco.2016.77

Plasma neuron-specific enolase level as a prognostic marker in patients with non-small cell lung cancer receiving gefitinib.

Determination of the presence of epidermal growth factor receptor (EGFR) gene mutation is useful for predicting the efficacy of gefitinib. However, the survival rate following the initiation of treatment with gefitinib varies among individuals. A retrospective study was conducted to investigate the associations of the pretreatment serum pro-gastrin-releasing peptide (pro-GRP) and plasma neuron-specific enolase (NSE) levels to the patient survival rate following initiation of treatment with gefitinib in non-small cell lung cancer (NSCLC) patients receiving gefitinib treatment. Patients with NSCLC harboring EGFR gene mutations who received gefitinib therapy between 2004 and 2012 were included in the study. Data from a total of 41 patients were analyzed. The serum pro-GRP level was measured in 31 patients and the plasma NSE in 22 patients. The progression-free survival (PFS) (P=0.013) and overall survival (OS) (P=0.014, log-rank test) rates decreased as the plasma NSE level increased. Statistical analysis using a Cox proportional hazards regression model adjusted for age, gender, performance status (PS) and disease stage showed that higher NSE levels were associated with shorter PFS (P=0.021) and OS (P=0.0024). By contrast, no association was detected between the serum level of pro-GRP and survival rate. The results suggest that pretreatment NSE measurement could be clinically useful in patients with NSCLC scheduled to receive gefitinib treatment.出版社サイトへのリンク: https://doi.org/10.3892/mco.2015.56

The dynamic balance of import and export of zinc in Escherichia coli suggests a heterogeneous population response to stress

Zinc is essential for life, but toxic in excess. Thus all cells must control their internal zinc concentration. We used a systems approach, alternating rounds of experiments and models, to further elucidate the zinc control systems in Escherichia coli. We measured the response to zinc of the main specific zinc import and export systems in the wild-type, and a series of deletion mutant strains. We interpreted these data with a detailed mathematical model and Bayesian model fitting routines. There are three key findings: first, that alternate, non-inducible importers and exporters are important. Second, that an internal zinc reservoir is essential for maintaining the internal zinc concentration. Third, our data fitting led us to propose that the cells mount a heterogeneous response to zinc: some respond effectively, while others die or stop growing. In a further round of experiments, we demonstrated lower viable cell counts in the mutant strain tested exposed to excess zinc, consistent with this hypothesis. A stochastic model simulation demonstrated considerable fluctuations in the cellular levels of the ZntA exporter protein, reinforcing this proposal. We hypothesize that maintaining population heterogeneity could be a bet-hedging response allowing a population of cells to survive in varied and fluctuating environments

NleC, a Type III Secretion Protease, Compromises NF-κB Activation by Targeting p65/RelA

The NF-κB signaling pathway is central to the innate and adaptive immune responses. Upon their detection of pathogen-associated molecular patterns, Toll-like receptors on the cell surface initiate signal transduction and activate the NF-κB pathway, leading to the production of a wide array of inflammatory cytokines, in attempt to eradicate the invaders. As a countermeasure, pathogens have evolved ways to subvert and manipulate this system to their advantage. Enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC) are closely related bacteria responsible for major food-borne diseases worldwide. Via a needle-like protein complex called the type three secretion system (T3SS), these pathogens deliver virulence factors directly to host cells and modify cellular functions, including by suppressing the inflammatory response. Using gain- and loss-of-function screenings, we identified two bacterial effectors, NleC and NleE, that down-regulate the NF-κB signal upon being injected into a host cell via the T3SS. A recent report showed that NleE inhibits NF-κB activation, although an NleE-deficient pathogen was still immune-suppressive, indicating that other anti-inflammatory effectors are involved. In agreement, our present results showed that NleC was also required to inhibit inflammation. We found that NleC is a zinc protease that disrupts NF-κB activation by the direct cleavage of NF-κB's p65 subunit in the cytoplasm, thereby decreasing the available p65 and reducing the total nuclear entry of active p65. More importantly, we showed that a mutant EPEC/EHEC lacking both NleC and NleE (ΔnleC ΔnleE) caused greater inflammatory response than bacteria carrying ΔnleC or ΔnleE alone. This effect was similar to that of a T3SS-defective mutant. In conclusion, we found that NleC is an anti-inflammatory bacterial zinc protease, and that the cooperative function of NleE and NleC disrupts the NF-κB pathway and accounts for most of the immune suppression caused by EHEC/EPEC

Usefulness of the Palliative Prognostic Index in patients with lung cancer.

The usefulness of the Palliative Prognostic Index (PPI) has been successfully validated in a variety of clinical settings. However, while lung cancer is the leading cause of death worldwide, patients with lung cancer accounted for only 6.9-25.8 % of the study populations in these previous studies. We conducted a retrospective study to evaluate the usefulness of the PPI for survival prediction in patients with lung cancer. Patients with lung cancer who were admitted to our hospital between 2009 and 2013 to receive palliative care were enrolled. The association between the Palliative Prognostic Index, determined based on the data recorded in the clinical charts at the last admission to our hospital, and survival was evaluated. The patient group with a PPI of >6 showed a significantly shorter survival time than the patient group with a PPI of ≤ 6 (P < 0.0001, log-rank test). The sensitivity and specificity of the PPI determined using the cutoff value of 6 for predicting less than 3 weeks of survival were 61.3 and 86.8 %, respectively. However, the sensitivity decreased to 50.0 % when the assessment was carried out in only patients with small cell lung carcinoma. Our findings suggest the existence of a close association between the PPI and survival in patients with lung cancer receiving palliative care. However, the sensitivity of the index for predicting less than 3 weeks of survival was relatively low in patients with small cell lung carcinoma

Akt1 in Osteoblasts and Osteoclasts Controls Bone Remodeling

Bone mass and turnover are maintained by the coordinated balance between bone formation by osteoblasts and bone resorption by osteoclasts, under regulation of many systemic and local factors. Phosphoinositide-dependent serine-threonine protein kinase Akt is one of the key players in the signaling of potent bone anabolic factors. This study initially showed that the disruption of Akt1, a major Akt in osteoblasts and osteoclasts, in mice led to low-turnover osteopenia through dysfunctions of both cells. Ex vivo cell culture analyses revealed that the osteoblast dysfunction was traced to the increased susceptibility to the mitochondria-dependent apoptosis and the decreased transcriptional activity of runt-related transcription factor 2 (Runx2), a master regulator of osteoblast differentiation. Notably, our findings revealed a novel role of Akt1/forkhead box class O (FoxO) 3a/Bim axis in the apoptosis of osteoblasts: Akt1 phosphorylates the transcription factor FoxO3a to prevent its nuclear localization, leading to impaired transactivation of its target gene Bim which was also shown to be a potent proapoptotic molecule in osteoblasts. The osteoclast dysfunction was attributed to the cell autonomous defects of differentiation and survival in osteoclasts and the decreased expression of receptor activator of nuclear factor-κB ligand (RANKL), a major determinant of osteoclastogenesis, in osteoblasts. Akt1 was established as a crucial regulator of osteoblasts and osteoclasts by promoting their differentiation and survival to maintain bone mass and turnover. The molecular network found in this study will provide a basis for rational therapeutic targets for bone disorders

Design and baseline characteristics of the finerenone in reducing cardiovascular mortality and morbidity in diabetic kidney disease trial

Background: Among people with diabetes, those with kidney disease have exceptionally high rates of cardiovascular (CV) morbidity and mortality and progression of their underlying kidney disease. Finerenone is a novel, nonsteroidal, selective mineralocorticoid receptor antagonist that has shown to reduce albuminuria in type 2 diabetes (T2D) patients with chronic kidney disease (CKD) while revealing only a low risk of hyperkalemia. However, the effect of finerenone on CV and renal outcomes has not yet been investigated in long-term trials. Patients and Methods: The Finerenone in Reducing CV Mortality and Morbidity in Diabetic Kidney Disease (FIGARO-DKD) trial aims to assess the efficacy and safety of finerenone compared to placebo at reducing clinically important CV and renal outcomes in T2D patients with CKD. FIGARO-DKD is a randomized, double-blind, placebo-controlled, parallel-group, event-driven trial running in 47 countries with an expected duration of approximately 6 years. FIGARO-DKD randomized 7,437 patients with an estimated glomerular filtration rate >= 25 mL/min/1.73 m(2) and albuminuria (urinary albumin-to-creatinine ratio >= 30 to <= 5,000 mg/g). The study has at least 90% power to detect a 20% reduction in the risk of the primary outcome (overall two-sided significance level alpha = 0.05), the composite of time to first occurrence of CV death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure. Conclusions: FIGARO-DKD will determine whether an optimally treated cohort of T2D patients with CKD at high risk of CV and renal events will experience cardiorenal benefits with the addition of finerenone to their treatment regimen. Trial Registration: EudraCT number: 2015-000950-39; ClinicalTrials.gov identifier: NCT02545049