Coxiella co-opts the Glutathione Peroxidase 4 to protect the host cell from oxidative stress-induced cell death

The causative agent of human Q fever, Coxiella burnetii, is highly adapted to infect alveolar macrophages by inhibiting a range of host responses to infection. Despite the clinical and biological importance of this pathogen, the challenges related to genetic manipulation of both C. burnetii and macrophages have limited our knowledge of the mechanisms by which C. burnetii subverts macrophages functions. Here, we used the related bacterium Legionella pneumophila to perform a comprehensive screen of C. burnetii effectors that interfere with innate immune responses and host death using the greater wax moth Galleria mellonella and mouse bone marrow-derived macrophages. We identified MceF (Mitochondrial Coxiella effector protein F), a C. burnetii effector protein that localizes to mitochondria and contributes to host cell survival. MceF was shown to enhance mitochondrial function, delay membrane damage, and decrease mitochondrial ROS production induced by rotenone. Mechanistically, MceF recruits the host antioxidant protein Glutathione Peroxidase 4 (GPX4) to the mitochondria. The protective functions of MceF were absent in primary macrophages lacking GPX4, while overexpression of MceF in human cells protected against oxidative stress-induced cell death. C. burnetii lacking MceF was replication competent in mammalian cells but induced higher mortality in G. mellonella, indicating that MceF modulates the host response to infection. This study reveals an important C. burnetii strategy to subvert macrophage cell death and host immunity and demonstrates that modulation of the host antioxidant system is a viable strategy to promote the success of intracellular bacteria.

PCBs occurrence in marine bivalves and fish from Todos os Santos Bay, Bahia, Brazil

In order to evaluate contamination by polychlorinated biphenyls (PCBs) in a tropical bay exposed to different anthropogenic pressures, samples of bivalves: mangrove oyster (Crassotrea rhizophorae), mangrove mussel (Mytella guyanensis)and clams (Anomalocardia brasiliana), were collected in different parts of Todos os Santos Bay, Bahia, Brazil. In addition, samples of bivalves and fish, purchased from a seafood market in the city of Salvador were analyzed to evaluate human exposure to PCBs through ingestion. Identification and quantification of PCBs were done by GC/MS after microwave extraction and purification with sulfuric acid. In bivalves, concentrations ranged from <0.08 to 50.1 ng g ^-1 (dry weight), with the highest values being detected in mangrove oyster, followed by clams and mangrove mussel of the Subaé estuary and Madre de Deus/Mataripe; regions known to be impacted by anthropic activities. From the total of the 12 fish species analyzed, only 5 presented levels of PCBs above the detection limit, ranging from 0.23 to 4.55 ng g ^-1 and 0.51 to 26.05 ng g ^-1 by dry weight and lipid weight, respectively. In general, concentrations of PCBs on the bay are lower than in most regions around the world, especially those located in the Northern Hemisphere. Indexes indicated that local biota and seafood from the fish market are not adversely impacted by PCBs and do not represent a risk to human health.

Macrophage priming is dispensable for NLRP3 inflammasome activation and restriction of Leishmania amazonensis replication

The NLRP3 inflammasome is activated in response to multiple stimuli and triggers activation of caspase-1 (CASP1), IL-1β production, and inflammation. NLRP3 activation requires two signals. The first leads to transcriptional regulation of specific genes related to inflammation, and the second is triggered when pathogens, toxins, or specific compounds damage cellular membranes and/or trigger the production of reactive oxygen species (ROS). Here, we assess the requirement of the first signal (priming) for the activation of the NLRP3 inflammasome in bone marrow-derived macrophages (BMDMs) infected with Leishmania amazonensis. We found that BMDMs express the inflammasome components NLRP3, ASC, and CASP1 at sufficient levels to enable the assembly and activation of NLRP3 inflammasome in response to infection. Therefore, priming was not required for the formation of ASC specks, CASP1 activation (measured by fluorescent dye FAM-YVAD), and restriction of L. amazonensis replication via the NLRP3 inflammasome. By contrast, BMDM priming was required for CASP1 cleavage (p20) and IL-1β secretion, because priming triggers robust up-regulation of pro-IL-1β and CASP11 that are important for efficient processing of CASP1 and IL-1β. Taken together, our data shed light into the cellular and molecular processes involved in activation of the NLRP3 in macrophages by Leishmania, a process that is important for the outcome of Leishmaniasis.

A functional glycoproteomics approach identifies CD13 as a novel E-selectin ligand in breast cancer

BACKGROUND

The glycan moieties sialyl-Lewis-X and/or -A (sLe^X/A) are the primary ligands for E-selectin, regulating subsequent tumor cell extravasation into distant organs. However, the nature of the glycoprotein scaffolds displaying these glycans in breast cancer remains unclear and constitutes the focus of the present investigation.

METHODS

We isolated glycoproteins that bind E-selectin from the CF1_T breast cancer cell line, derived from a patient with ductal carcinoma. Proteins were identified using bottom-up proteomics approach by nanoLC-orbitrap LTQ-MS/MS. Data were curated using bioinformatics tools to highlight clinically relevant glycoproteins, which were validated by flow cytometry, Western blot, immunohistochemistry and in-situ proximity ligation assays in clinical samples.

RESULTS

We observed that the CF1_T cell line expressed sLe^X, but not sLe^A and the E-selectin reactivity was mainly on N-glycans. MS and bioinformatics analysis of the targeted glycoproteins, when narrowed down to the most clinically relevant species in breast cancer, identified CD44 glycoprotein (HCELL) and CD13 as key E-selectin ligands. Additionally, the co-expression of sLe^X-CD44 and sLe^X-CD13 was confirmed in clinical breast cancer tissue samples.

CONCLUSIONS

Both CD44 and CD13 glycoforms display sLe^X in breast cancer and bind E-selectin, suggesting a key role in metastasis development. Such observations provide a novel molecular rationale for developing targeted therapeutics.

GENERAL SIGNIFICANCE

While HCELL expression in breast cancer has been previously reported, this is the first study indicating that CD13 functions as an E-selectin ligand in breast cancer. This observation supports previous associations of CD13 with metastasis and draws attention to this glycoprotein as an anti-cancer target.

A Novel Method for Studying the Pharmacokinetics of [(14) C]Umeclidinium After Application to the Axilla or Palm of Healthy Male Subjects

Umeclidinium (UMEC), a long-acting muscarinic antagonist approved for chronic obstructive pulmonary disease (COPD), was investigated for primary hyperhidrosis as topical therapy. This study evaluated the pharmacokinetics, safety, and tolerability of a single dose of [(14) C]UMEC applied to either unoccluded axilla (UA), occluded axilla (OA), or occluded palm (OP) of healthy males. After 8 h the formulation was removed. [(14) C]UMEC plasma concentrations (Cp) were quantified by accelerator mass spectrometry. Occlusion increased systemic exposure by 3.8-fold. Due to UMEC absorption-limited pharmacokinetics, Cp data from the OA were combined with intravenous data from a phase I study. The data were described by a two-compartment population model with sequential zero and first-order absorption and linear elimination. Simulated systemic exposure following q.d. doses to axilla was similar to the exposure from the inhaled therapy, suggesting that systemic safety following dermal administration can be bridged to the inhaled program, and offering the potential for a reduced number of studies and/or subjects.

Influence of proximity to an urban center in the pattern of contamination by marine debris

In order to test the relationship between the occurrence of marine debris and the distance from urban areas, nine beaches in the metropolitan area of Salvador, Bahia, Brazil and the adjacent northern coast were studied. Marine debris were collected, sorted in several categories and weighed. It was observed that plastics were numerically the most abundant component of the collected debris. As expected, the beaches closest to Salvador presented the largest density of debris, with the exception of the Porto da Barra beach, which has an efficient public cleaning system and does not have any vegetation, making it difficult to accumulate solid waste. Linear regression analyses showed significant relationships between the distance from the urban center (Salvador) and the number of marine debris per m(2), the total number of debris per beach (abundance), and the diversity of debris types (richness). The results showed that proximity to urban regions was a key factor in the marine debris distribution along the coast.

CD147 overexpression allows an accurate discrimination of bladder cancer patients' prognosis

BACKGROUND

Urothelial bladder carcinoma (UBC) is a chemo-sensitive tumour, but the response to treatment is heterogeneous. CD147 has been associated with chemotherapy resistance. We aimed to define tumours with an aggressive phenotype by the combined analysis of clinicopathological and biological parameters.

METHODS

77 patients with T1G3 or muscle-invasive UBC treated by radical cystectomy were studied. Immunohistochemistry was performed to detect CD147, heparanase, CD31 (blood vessels identification) and D2-40 (lymphatic vessels identification) expressions. The immunohistochemical reactions were correlated with the clinicopathological and the outcome parameters. 5-year disease-free survival (DFS) and overall survival (OS) rates were estimated using the Kaplan-Meier method. Multivariate analysis was performed by Cox proportional hazards analysis.

RESULTS

The 5-year DFS and OS rates were significantly influenced by the classical clinicopathological parameters, and by the occurrence of lymphovascular invasion. CD147 and heparanase immunoexpression did not affect patients' outcome. However, patients with pT3/pT4 tumours had a median OS time of 14.7 months (95% CI 7.1-22.3, p = 0.003), which was reduced to 9.2 months (95% CI 1.5-17.0, p = 0.008) if the tumours were CD147 positive. We developed a model of tumour aggressiveness using parameters as stage, grade, lymphovascular invasion and CD147 immunoexpression, which separated a low aggressiveness from a high aggressiveness group, remaining as an independent prognostic factor of DFS (HR 3.746; 95% CI 1.244-11.285; p = 0.019) and OS (HR 3.247; 95% CI 1.015-10.388, p = 0.047).

CONCLUSION

CD147 overexpression, included in a model of UBC aggressiveness, may help surgeons to identify patients who could benefit from a personalized therapeutic regimen. Additional validation is needed.

PKU in Minas Gerais State, Brazil: mutation analysis

This work was undertaken in order to ascertain the PKU mutational spectrum in Minas Gerais, Brazil, the relative frequency of the mutations in the State and the origin of these mutations by haplotype determination. Minas Gerais is a trihybrid population formed by miscegenation from Europeans, Africans and Amerindians. All 13 exons of the PAH gene from 78 PKU patients were analyzed, including splicing sites and the promoter region. We identified 30 different mutations and 98% of the PAH alleles were established. A new mutation (Q267X) was identified as well. The most common mutations found were V388M (21.2), R261Q (16.0%), IVS10-11G>A (15.3%), I65T (5.8%), IVS2+5G>C (5.8%), R252W (5.1%), IVS2+5G>A (4.5%), P281L (3.8%) and L348V (3.2%). These nine mutations correspond to 80% of the PKU alleles in the state. Haplotypes were determined to characterize the origin of the PAH alleles. The majority of the mutations found, with respective haplotypes, are frequent in the Iberian Peninsula. However, there were some mutations that are rare in Europe and four previously unreported mutation-haplotype associations. I65T and Q267X were found in association with haplotype 38 and may be African in origin or the result of miscegenation in the Brazilian population.

Reduced arthritis in MIF deficient mice is associated with reduced T cell activation: down-regulation of ERK MAP kinase phosphorylation

Macrophage migration inhibitory factor (MIF) is a pleiotropic pro-inflammatory cytokine with many cellular targets in rheumatoid arthritis (RA). MIF has been reported to activate cells via mitogen-activated protein kinase and serine/threonine kinase (AKT or protein kinase B)-dependent signal transduction pathways. Its contribution to T cell activation and signalling in RA is not known. Using MIF -/- mice and a T cell-mediated model of RA, antigen-induced arthritis, we investigated the role of MIF in T cell activation and signalling. Arthritis severity was significantly reduced in MIF -/- mice compared with wildtype mice. This reduction was associated with decreased T cell activation parameters including footpad delayed type hypersensitivity, antigen-induced splenocyte proliferation and cytokine production. Splenocyte proliferation required extracellular signal-regulated kinase (ERK)1/2 phosphorylation, and decreased T cell activation in MIF -/- mice was associated with decreased phosphorylation of ERK1/2 but not AKT. Collectively, these data suggest that MIF promotes antigen-specific immune responses via regulation of ERK phosphorylation in T cells.

Extravasation mucocele involving the ventral surface of the tongue (glands of Blandin-Nuhn)

BACKGROUND

Mucocele is a lesion that involves the salivary glands and respective current ducts caused mainly by traumas in the affected area. Two different histological forms can be found: extravasation phenomenon and mucus-retention cyst where the former is the most frequently observed involving minor salivary glands such as the glands present in the anterior portion of the ventral surface of the tongue (glands of Blandin-Nuhn).

CASE REPORT

This report describes a large lesion involving the ventral surface of the tongue that was definitively diagnosed by histological examination as extravasation mucocele.

CONCLUSION

Important concepts are reviewed to help clinicians correctly diagnose and treat this pathology.

Expression of cell-cycle regulatory proteins and their prognostic value in superficial low-grade urothelial cell carcinoma of the bladder

AIMS

Cell-cycle regulatory proteins are important indicators in determining progression trough the cell-cycle and progression to invasive cancer in patients presenting with superficial bladder cancer. We performed an immunohistochemical study in order to evaluate the prognostic value of the expression of p16, p27, pRb, p53 and Ki-67 in superficial grade I and II papillary urothelial cell carcinoma of the bladder.

METHODS

p16, p27, p53, pRb and Ki-67 immunoexpression was studied in 14 pTa, 35 pT1a and 7 pT1b bladder tumours at presentation and at recurrence of their tumours. The recurrence-free survival and the progression-free survival were analysed according to these regulatory cell-cycle proteins expression.

RESULTS

For survival in univariate analysis a high Ki-67 labelling index was a poor prognostic factor for recurrence-free and progression-free survival (P=0.0014 and P=0.012, respectively). Ki-67 labelling index was also an independent recurrence-free survival prognostic factor (P=0.0005). The p16, p27, p53 and pRb immunoreactivity was not significantly associated with recurrence or progression rate in this group of bladder carcinomas.

CONCLUSIONS

These data suggest that the Ki-67 labelling index can be a reliable marker in predicting recurrence and/or progression in superficial low-grade bladder carcinomas and may be relevant in planning adjuvant therapy.

P-selectin requirement for neutrophil accumulation and injury in the direct passive Arthus reaction

The aim of this study was to investigate the role of P-selectin in the accumulation of neutrophils in the direct passive Arthus reaction in rat skin. Direct passive Arthus dermal reaction was induced in male Sprague-Dawley (SD) rats by a single i.v. injection of rat anti-sheep globulin (SG) 1 h before i.d. injection of SG antigen. Anti-P-selectin or irrelevant control antibody was given 1 h before rat anti-SG injection. Complement depletion was also performed in a separate group by pretreatment with cobra venom factor (CVF). In all groups dermal swelling was assessed 4 h after antigen challenge. Four hours after antigen challenge, rats treated with control antibody developed skin swelling (2.29 +/- 0.47 mm), prominent complement deposition and neutrophil accumulation. This response was associated with local up-regulation of endothelial P-selectin. Pre-treatment with anti-P-selectin antibody 1 h before passive Arthus induction prevented skin swelling (0.29 +/- 0.06 mm, P < 0.05, cf with control antibody treatment), neutrophil accumulation and up-regulation of endothelial P-selectin despite complement deposition. CVF treatment prevented complement deposition, neutrophil accumulation and skin swelling (0.13 +/- 0.07 mm, P < 0.05, cf with saline treatment). However, endothelial P-selectin expression was still present. Inhibition of skin swelling and neutrophil accumulation in direct passive Arthus by functional inhibition of P-selectin suggest a pivotal role for this adhesion molecule in this inflammatory process. These results also suggest that multiple steps are involved in the evolution of direct passive Arthus, including both P-selectin expression and complement activation. However, while complement activation is essential for neutrophil accumulation and expression of dermal injury, P-selectin up-regulation initiated by antibody/antigen deposition occurs independently of complement activation.

Glucocorticoid inhibition of adjuvant arthritis synovial macrophage nitric oxide production: role of lipocortin 1

Nitric oxide (NO) is a mediator of inflammatory injury which is inhibited by glucocorticoids and is implicated in rheumatoid (RA) and adjuvant arthritis (AA). The glucocorticoid-induced anti-inflammatory molecule lipocortin 1 is expressed in RA synovium, but the effects of lipocortin 1 on synovial inflammation have been little studied. We investigated the effects of glucocorticoids and lipocortin 1 on inducible NO synthase (iNOS) and glucocorticoids on the induction of lipocortin 1 in AA synovial macrophages. NO production was measured by Griess assay in supernatants of day 14 AA rat synovial explants and of synovial macrophages purified from enzyme-digested synovium and treated with lipopolysaccharide (LPS) 1 microg/ml, dexamethasone (DEX) 10(-7) M, and anti-lipocortin 1 MoAb. iNOS and lipocortin 1 expression were detected by flow cytometry using specific MoAb. Cell surface lipocortin was determined by Western blot. NO was produced by all AA synovial explants and NO was released by cultured synovial macrophages (14.5 +/- 2.1 micromol/24 h). iNOS was detected in synovial macrophages (ED-1+) by permeabilization flow cytometry. LPS increased synovial macrophage NO release (P < 0.0001) and iNOS expression (P = 0.04). DEX inhibited constitutive (P = 0.002) and LPS-induced (P < 0.001) NO release and iNOS expression (P = 0.03). DEX inhibition of synovial macrophage NO was associated with induction of cell surface and intracellular lipocortin 1. Anti-lipocortin 1 MoAb treatment reduced the inhibition of NO release by DEX (P = 0.002), but had no effect on iNOS expression. These findings demonstrate a role for lipocortin I in the inhibition by glucocorticoids of AA synovial macrophage iNOS activity.

Suppression of adjuvant arthritis and synovial macrophage inducible nitric oxide by N-iminoethyl-L-ornithine, a nitric oxide synthase inhibitor

Nitric oxide (NO.) is a pro-inflammatory effector molecule in certain inflammatory diseases, including arthritis. We investigated the production of NO. by adjuvant arthritis (AA) synovial macrophages, and studied the effects of a NO. synthase inhibitor. N-iminoethyl-L-ornithine (L-NIO). Compared to control rats, rats treated with L-NIO in vivo exhibited significantly lower articular index (p < 0.05), paw volume (p < 0.05), and synovial fluid cell count (p < 0.05). No effect on cutaneous delayed-type hypersensitivity to the disease-initiating antigen was observed. Inducible NO. synthase (iNOS) was detected in AA synovial macrophages, and cultured AA synovial macrophage iNOS levels were increased by a factor of 138 +/- 17% (p < 0.01) by 1 microgram/ml LPS in vitro. Constitutive NO. production by AA synovial macrophages (43 +/- 1 nmol/10(5) cells/24 h) was significantly inhibited by 10 nM L-NIO in vitro (32 +/- 0.5, p < 0.01). NO. production induced by 1 microgram/ml LPS (48 +/- 2) was also decreased by L-NIO (39 +/- 2, p < 0.05). In vivo L-NIO treatment also inhibited alveolar macrophage NO. production (p < 0.05). The ability of L-NIO to decrease iNOS-mediated synovial macrophage NO. production and inhibit the clinical parameters of AA implicate macrophage-derived NO. in the pathogenesis of this disease.

Anti-neutrophil monoclonal antibody therapy inhibits the development of adjuvant arthritis

The aim of this study was to determine the contribution of neutrophils to adjuvant arthritis (AA) by in vivo depletion of peripheral blood neutrophils. Specific anti-neutrophil MoAb, RP3 (10 mg), or a control antibody was given twice daily on days 8-11 after injection of Mycobacterium tuberculosis in inbred male Sprague-Dawley rats. RP3 treatment inhibited the neutrophil leukocytosis associated with AA (3.3 +/- 0.6 x 10(3)/mm3 versus 21.2 +/- 6.9 x 10(3)/mm3; P<0.001). On day 12, control animals exhibited severe arthritis as assessed by articular index (AI) (9.2 +/- 1.3), increase in paw volume (149.3 +/- 10.6%), and synovial fluid (SF) cell count (5.3 +/- 0.5 x 10(5)). RP3 treatment significantly reduced AI (1 +/- 0.1; P<0.001), paw volume (103.6 +/- 5.8%; P<0.001) and SF cells (0.6 +/- 0.1 x 10(5); P<0.001) without affecting cutaneous DTH (treated 0.6 +/- 0.1 mm change in thickness, control 0.8 +/- 0.2 mm; NS). Additional experiments demonstrated that CD4+ cell depletion but not decomplementation inhibited AA development and synovial neutrophil accumulation. Depletion of circulating neutrophils prevented joint inflammation and synovial leucocyte influx in AA, suggesting a pivotal role for neutrophils in the effector phase of AA. Inhibition of neutrophil accumulation by CD4+ cell depletion and not by decomplementation suggests that neutrophil accumulation in AA is T cell-dependent.