Helicobacter pylori PqqE is a new virulence factor that cleaves junctional adhesion molecule A and disrupts gastric epithelial integrity

Helicobacter pylori infects approximately half of the world's population and is the strongest risk factor for peptic ulcer disease and gastric cancer, representing a major global health concern. H. pylori persistently colonizes the gastric epithelium, where it subverts the highly organized structures that maintain epithelial integrity. Here, a unique strategy used by H. pylori to disrupt the gastric epithelial junctional adhesion molecule-A (JAM-A) is disclosed, using various experimental models that include gastric cell lines, primary human gastric cells, and biopsy specimens of infected and non-infected individuals. H. pylori preferentially cleaves the cytoplasmic domain of JAM-A at Alanine 285. Cells stably transfected with full-length JAM-A or JAM-A lacking the cleaved sequence are used in a range of functional assays, which demonstrate that the H. pylori cleaved region is critical to the maintenance of the epithelial barrier and of cell-cell adhesion. Notably, by combining chromatography techniques and mass spectrometry, PqqE (HP1012) is purified and identified as the H. pylori virulence factor that cleaves JAM-A, uncovering a previously unreported function for this bacterial protease. These findings propose a novel mechanism for H. pylori to disrupt epithelial integrity and functions, breaking new ground in the understanding of the pathogenesis of this highly prevalent and clinically relevant infection.

The Two Faces of Tumor-Associated Macrophages and Their Clinical Significance in Colorectal Cancer

Macrophages are one of the immune populations frequently found in colorectal tumors and high macrophage infiltration has been associated with both better and worst prognosis. Importantly, according to microenvironment stimuli, macrophages may adopt different polarization profiles, specifically the pro-inflammatory or M1 and the anti-inflammatory or M2, which display distinct functions. Therefore, concomitantly with the number of tumor-associated macrophages (TAMs), their characterization is fundamental to unravel their relevance in cancer. Here, we profiled macrophages in a series of 150 colorectal cancer (CRC) cases by immunohistochemistry, using CD68 as a macrophage lineage marker, CD80 as a marker of pro-inflammatory macrophages, and CD163 as a marker of anti-inflammatory macrophages. Quantifications were performed by computer-assisted analysis in the intratumoral region, tumor invasive front, and matched tumor adjacent normal mucosa (ANM). Macrophages, specifically the CD163⁺ ones, were predominantly found at the tumor invasive front, whereas CD80⁺ macrophages were almost exclusively located in the ANM, which suggests a predominant anti-inflammatory polarization of TAMs. Stratification according to tumor stage revealed that macrophages, specifically the CD163⁺ ones, are more prevalent in stage II tumors, whereas CD80⁺ macrophages are predominant in less invasive T1 tumors. Specifically in stage III tumors, higher CD68, and lower CD80/CD163 ratio associated with decreased overall survival. Importantly, despite the low infiltration of CD80⁺ cells in colorectal tumors, multivariate logistic regression revealed a protective role of these cells regarding the risk for relapse. Overall, this work supports the involvement of distinct microenvironments, present at the intra-tumor, invasive front and ANM regions, on macrophage modulation, and uncovers their prognostic value, further supporting the relevance of including macrophage profiling in clinical settings.

Chitosan/poly(γ-glutamic acid) nanoparticles incorporating IFN-γ for immune response modulation in the context of colorectal cancer

IFN-γ therapy has been approved by the Food and Drug Administration (FDA) for the treatment of chronic granulomatous disease and severe malignant osteopetrosis. Despite the promising IFN-γ-based therapeutic applications, its limited success in clinical trials is related with limitations inherent to its molecular properties and with the difficulties to deliver it locally or with adequate periodicity to achieve a therapeutic effect. We have previously shown that chitosan (Ch)/poly(γ-glutamic acid) (γ-PGA) nanoparticles (NPs) are immunostimulatory, impairing colorectal cancer cell invasion. Ch is a biocompatible cationic polysaccharide extensively studied and already approved for biomedical applications while γ-PGA is a poly(amino acid), biodegradable and negatively charged. Here, we evaluated the potential of Ch/γ-PGA NPs as vehicles for IFN-γ and their ability to modulate immune cells' phenotype. In this study, Ch/IFN-γ/γ-PGA nanoparticles (IFN-γ-NPs) prepared by a co-acervation method, presenting a size of approximately 180 nm and a low polydispersity index, were tested for their immunomodulatory activity. These IFN-γ-NPs induced an immunostimulatory profile on dendritic cells (DCs) with increased cell surface costimulatory molecules and secretion of pro-inflammatory cytokines, including IL-6, IL-12p40 and TNF-α. IFN-γ-NPs also modulated the IL-10-stimulated macrophage profile, increasing their ability to secrete the pro-inflammatory cytokines IL-6, IL-12p40 and TNF-α. Concomitantly, these phenotypic alterations enhanced T cell proliferation. In addition, the ability of DCs and macrophages to induce colorectal cancer cell invasion was hampered in the presence of IFN-γ-NPs. Although the major observations were mediated by Ch/γ-PGA NPs, the incorporation of IFN-γ into NPs potentiated the expression of CD40 and CD86, and the impairment of colorectal cancer cell invasion. This work bridges the previously reported immunostimulatory capacity of Ch/γ-PGA NPs with their potential as carriers for immunomodulatory molecules, like IFN-γ, opening new avenues for their use in clinical settings.

Pro-inflammatory chitosan/poly(γ-glutamic acid) nanoparticles modulate human antigen-presenting cells phenotype and revert their pro-invasive capacity

Anticancer immune responses depend on efficient presentation of tumor antigens and co-stimulatory signals provided by antigen-presenting cells (APCs). However, it is described that immature dendritic cells (DCs) and macrophages at the tumor site may have an immunosuppressive profile, which limits the activity of effector T cells and supports tumor progression. Therapeutic targeting of these innate immune cells, either aiming at their elimination or re-polarization towards an immunostimulatory profile, has been pointed as an attractive approach to control tumor progression. In the present work, we assessed the potential of Chitosan (Ch)/Poly(γ-glutamic acid) (γ-PGA) nanoparticles (NPs) to modulate macrophages and DCs inflammatory profile and to impair their ability to promote cancer cell invasion. Interestingly, Ch/γ-PGA NPs, prepared by co-acervation method, induced an immunostimulatory DCs phenotype, enhancing the expression of the co-stimulatory molecules CD86, CD40 and HLA-DR, and the secretion of the pro-inflammatory cytokines TNF-α, IL-12p40 and IL-6. Furthermore, Ch/γ-PGA NPs re-educated IL-10-stimulated macrophages towards a pro-inflammatory profile, decreasing the expression of CD163 and promoting the secretion of IL-12p40 and TNF-α. These alterations in the immune cells phenotype promoted CD4⁺ and CD8⁺ T cell activation/proliferation and partially inhibited APCs' ability to induce colorectal cancer cell invasion. Overall, our findings open new perspectives on the use of Ch/γ-PGA NPs as an immunomodulatory therapy for antigen-presenting cells reprogramming, providing a new tool for anticancer therapies.

STATEMENT OF SIGNIFICANCE

The immune system is responsible to detect and destroy abnormal cells preventing the development of cancer. However, the immunosuppressive tumor microenvironment can compromise the immune response favoring tumor progression. Thus, immune system modulation towards an immunostimulatory profile can improve anticancer therapies. This research focus on the development of chitosan/poly(γ-glutamic acid) nanoparticles (NPs) to modulate human antigen-presenting cells (APCs) phenotype and to counteract their pro-invasive capacity. Interestingly, Ch/γ-PGA NPs had a prominent effect in inducing macrophages and dendritic cells immunostimulatory phenotype, thus favoring T cell proliferation and inhibiting colorectal cancer cell invasion. We propose that their combination with other immunomodulatory drugs or conventional anticancer therapies can improve patients' outcome.

Intricate Macrophage-Colorectal Cancer Cell Communication in Response to Radiation

Both cancer and tumour-associated host cells are exposed to ionizing radiation when a tumour is subjected to radiotherapy. Macrophages frequently constitute the most abundant tumour-associated immune population, playing a role in tumour progression and response to therapy. The present work aimed to evaluate the importance of macrophage-cancer cell communication in the cellular response to radiation. To address this question, we established monocultures and indirect co-cultures of human monocyte-derived macrophages with RKO or SW1463 colorectal cancer cells, which exhibit higher and lower radiation sensitivity, respectively. Mono- and co-cultures were then irradiated with 5 cumulative doses, in a similar fractionated scheme to that used during cancer patients' treatment (2 Gy/fraction/day). Our results demonstrated that macrophages sensitize RKO to radiation-induced apoptosis, while protecting SW1463 cells. Additionally, the co-culture with macrophages increased the mRNA expression of metabolism- and survival-related genes more in SW1463 than in RKO. The presence of macrophages also upregulated glucose transporter 1 expression in irradiated SW1463, but not in RKO cells. In addition, the influence of cancer cells on the expression of pro- and anti-inflammatory macrophage markers, upon radiation exposure, was also evaluated. In the presence of RKO or SW1463, irradiated macrophages exhibit higher levels of pro-inflammatory TNF, IL6, CCL2 and CCR7, and of anti-inflammatory CCL18. However, RKO cells induce an increase of macrophage pro-inflammatory IL1B, while SW1463 cells promote higher pro-inflammatory CXCL8 and CD80, and also anti-inflammatory VCAN and IL10 levels. Thus, our data demonstrated that macrophages and cancer cells mutually influence their response to radiation. Notably, conditioned medium from irradiated co-cultures increased non-irradiated RKO cell migration and invasion and did not impact on angiogenesis in a chicken embryo chorioallantoic membrane assay. Overall, the establishment of primary human macrophage-cancer cell co-cultures revealed an intricate cell communication in response to ionizing radiation, which should be considered when developing therapies adjuvant to radiotherapy.

Mesenteric lymph node granulomatous lesions in naturally infected wild boar (Sus scrofa) in Portugal--Histological, immunohistochemical and molecular aspects

Several studies have demonstrated that wildlife reservoirs of mycobacteria are responsible for the maintenance and spreading of the infection to livestock and wildlife counterparts. Recent data report the role of wild boar (Sus scrofa) as a reservoir for Mycobacterium bovis. This study was conducted to evaluate the chronic inflammatory response in the mesenteric lymph nodes (MLN) of wild boar with granulomatous lymphadenitis (n=30). Morphological parameters of the lesions were recorded. The expression of CD3 and CD79α molecules was evaluated by immunohistochemistry. Molecular genotyping and culture to identify mycobacteria were performed. The lesions consisted mainly of stage III and stage IV granulomas. CD3 and CD79α positive cells were observed in 15 (50%) and in 11 (36.6%) MLN, respectively. In these lesions, higher percentages of T lymphocytes were found and a limited number of animals exhibited a tendency for an increased percentage of B lymphocytes. Our results suggest that there are similar percentages and distribution patterns of CD3 and CD79α in the lesions, regardless of the presence of Mycobacterium avium subsp. paratuberculosis (Map), M. bovis or Map-M. bovis co-infection, and confirm that wild boar is both susceptible and could be an important Map and M. bovis wild reservoir in the study area.

An interferon-γ-delivery system based on chitosan/poly(γ-glutamic acid) polyelectrolyte complexes modulates macrophage-derived stimulation of cancer cell invasion in vitro

Macrophages represent a large component of the tumour microenvironment and are described to establish interactions with cancer cells, playing crucial roles in several stages of cancer progression. The functional plasticity of macrophages upon stimulation from the environment makes them susceptible to the influence of cancer cells and also renders them as promising therapeutic targets. In this work, we describe a drug delivery system to modulate the phenotype of macrophages, converting them from the pro-tumour M2 phenotype to the anti-tumour M1 phenotype, based on the incorporation of a pro-inflammatory cytokine (interferon-γ) in chitosan (Ch)/poly(γ-glutamic acid) (γ-PGA) complexes. Ch is a biocompatible cationic polysaccharide extensively studied and γ-PGA is a biodegradable, hydrophilic and negatively charged poly-amino acid. These components interact electrostatically, due to opposite charges, resulting in self-assembled structures that can be designed to deliver active molecules such as drugs and proteins. Ch and γ-PGA were self-assembled into polyelectrolyte multilayer films (PEMs) of 371nm thickness, using the layer-by-layer method. Interferon-γ (IFN-γ) was incorporated within the Ch layers at 100 and 500ng/mL. Ch/γ-PGA PEMs with IFN-γ were able to modulate the phenotype of IL-10-treated macrophages at the cell cytoskeleton and cytokine profile levels, inducing an increase of IL-6 and a decrease of IL-10 production. More interestingly, the pro-invasive role of IL-10-treated macrophages was hindered, as their stimulation of gastric cancer cell invasion in vitro decreased from 4 to 2-fold, upon modulation by Ch/γ-PGA PEMs with IFN-γ. This is the first report proposing Ch/γ-PGA PEMs as a suitable strategy to incorporate and release bioactive IFN-γ with the aim of modulating macrophage phenotype, counteracting their stimulating role on gastric cancer cell invasion.

Matrix metalloproteases as maestros for the dual role of LPS- and IL-10-stimulated macrophages in cancer cell behaviour

Background

The interactions established between macrophages and cancer cells are largely dependent on instructions from the tumour microenvironment. Macrophages may differentiate into populations with distinct inflammatory profiles, but knowledge on their role on cancer cell activities is still very scarce. In this work, we investigated the influence of pro-inflammatory (LPS-stimulated) and anti-inflammatory (IL-10-stimulated) macrophages on gastric and colorectal cancer cell invasion, motility/migration, angiogenesis and proteolysis, and the associated molecular mechanisms.

Methods

Following exposure of gastric and colon cancer cell lines to LPS- and IL-10-stimulated human macrophages, either by indirect contact or conditioned media, we analyzed the effect of the different macrophage populations on cancer cell invasion, migration, motility and phosphorylation status of EGFR and several interacting partners. Cancer-cell induced angiogenesis upon the influence of conditioned media from both macrophage populations was assessed using the chick embryo chorioallantoic membrane assay. MMP activities were evaluated by gelatin zymograhy.

Results

Our results show that IL-10-stimulated macrophages are more efficient in promoting in vitro cancer cell invasion and migration. In addition, soluble factors produced by these macrophages enhanced in vivo cancer cell-induced angiogenesis, as opposed to their LPS-stimulated counterparts. We further demonstrate that differences in the ability of these macrophage populations to stimulate invasion or angiogenesis cannot be explained by the EGFR-mediated signalling, since both LPS- and IL-10-stimulated macrophages similarly induce the phosphorylation of cancer cell EGFR, c-Src, Akt, ERK1/2, and p38. Interestingly, both populations exert distinct proteolytic activities, being the IL-10-stimulated macrophages the most efficient in inducing matrix metalloprotease (MMP)-2 and MMP-9 activities. Using a broad-spectrum MMP inhibitor, we demonstrated that proteolysis was essential for macrophage-mediated cancer cell invasion and angiogenesis.

Conclusions

We propose that IL-10- and LPS-stimulated macrophages distinctly modulate gastric and colorectal cancer cell behaviour, as result of distinct proteolytic profiles that impact cell invasion and angiogenesis.

New Insights into Mycobacterium bovis Prevalence in Wild Mammals in Portugal

A survey to determine the prevalence of Mycobacterium bovis in wild mammals in Portugal was conducted by testing samples from hunted animals and those found dead between 2009 and 2013. In this study, we investigated 2116 wild mammals. Post-mortem examinations were performed, and tissues were collected from wild mammals representing 8 families and 11 different species, with a total of 393 animals analysed. Cultures were performed, and acid-fast isolates were identified by PCR. Tissues were also screened for Mycobacterium bovis by directly extracting DNA and testing for the Mycobacterium bovis-specific sequences. Mycobacterium bovis prevalence was 26.9% (95% CI: 22.8-31.5%). Mycobacterium bovis was recorded in 106 of the 393 studied species: prevalence by species were 26.9% (95% CI: 16.8-40.2%) in red foxes, 20.0% (95% CI: 7.0-45.2%) in Egyptian mongooses, 21.4% (95% CI: 16.2-27.7%) in wild boar and 38.3% (95% CI: 29.9-47.4%) in red deer. Mycobacterium bovis infection was detected in six of eight taxonomic families. For some species, the small sample sizes obtained were a reflection of their restricted range and low abundance, making estimates of infection prevalence very difficult (1 beech marten of 4; 1 Eurasian otter of 3; 2 common genet of 3). Infection was not detected in European badgers, hedgehog, wild rabbits and hare. The results of this study confirm the presence of Mycobacterium bovis infection in wild carnivores in Portugal.

Maximal respiratory pressures among adolescent swimmers

Maximal inspiratory pressures (MIP) and maximal expiratory pressures (MEP) are useful indices of respiratory muscle strength in athletes. The aims of this study were: to describe the strength of the respiratory muscles of Olympic junior swim team, at baseline and after a standard physical training; and to determine if there is a differential inspiratory and expiratory pressure response to the physical training. A cross-sectional study evaluated 28 international-level swimmers with ages ranging from 15 to 17 years, 19 (61 %) being males. At baseline, MIP was found to be lower in females (P = .001). The mean values reached by males and females were: MIP(cmH2O) = M: 100.4 (± 26.5)/F: 67.8 (± 23.2); MEP (cmH2O) = M: 87.4 (± 20.7)/F: 73.9 (± 17.3). After the physical training they reached: MIP (cmH2O) = M: 95.3 (± 30.3)/F: 71.8 (± 35.6); MEP (cmH2O) = M: 82.8 (± 26.2)/F: 70.4 (± 8.3). No differential pressure responses were observed in either males or females. These results suggest that swimmers can sustain the magnitude of the initial maximal pressures. Other studies should be developed to clarify if MIP and MEP could be used as a marker of an athlete's performance.

Comparative evaluation of PCR in Ziehl-Neelsen stained smears and PCR in tissues for diagnosis of Mycobacterium avium subsp. paratuberculosis

Thirty six tissues from sheep, previously diagnosed with paratuberculosis, were tested by PCR in positive Ziehl-Neelsen staining smears of tissues, and PCR in tissues targeting IS900 specific for Mycobacterium avium subsp. paratuberculosis. DNA amplification was achieved in 33.3% Ziehl-Neelsen smears, and in 61.1% tissue samples. Combination of both techniques found 66.7% samples as positive. Combination of techniques would, therefore, increase the sensitivity of diagnosis.

Insulin sensitivity and insulin secretion in lean and obese normal pregnant women

An insulin-modified frequently sampled intravenous glucose tolerance test with minimal model analysis was performed in normal pregnant women between 28-32 weeks of gestation, to assess insulin sensitivity and insulin secretion. Insulin sensitivity in the pregnant group (no. 26) was reduced to approximately 50% that of nonpregnant group (no. 27) (p < 0.05). This increased insulin resistance was compensated by an enhancement of the first phase of insulin secretion, which was increased more than twofold in the pregnant women when compared with the nonpregnant women (p < 0.05). There was a trend toward greater insulin resistance and insulin secretion in the obese pregnant women (no. 7) as compared with the lean pregnant women (no. 19) although this difference was not statistically significant. Our findings confirm that late pregnancy is a state of physiologic insulin resistance compensated by an increase of insulin secretion.

Influence of exercise-induced maternal stress on fetal outcome in Wistar rats: inter-generational effects

The effects of physical activity during pregnancy and lactation on the fetal outcome and the growth of pups was studied in Wistar rats (n 144). Rats were trained to swim for 2 h every day, 6 d/week through pre-pregnancy, pregnancy and lactation. Maternal exercise during pregnancy, despite the dams having ad lib. access to food, resulted in low-birth-weight pups (5.6 (SD 0.7) g; n 178 in exercised dams v. 6.2 (SD 0.8) g; n 238 in sedentary dams). Maternal exercise continued through lactation exaggerated further the growth retardation of these pups (30.0 (SD 4.7) g; n 78 in exercised dams v. 36.0 (SD 6.9) g; n 126 in sedentary dams). The effects of maternal exercise during pregnancy and lactation studied over two successive generations revealed a reduction in the growth rates of the second generation progeny of both exercised (5.3 (SD 0.9) g; n 125 at birth and 25.1 (SD 6.8) g; n 54 at weaning) and sedentary rats (6.0 (SD 0.2) g; n 110 at birth and 31.3 (SD 4.3) g at weaning) born to first-generation exercised rats. While slower growth in the former indicates a cumulative effect of exercise stress over two generations, that of the latter indicates that the generational effects are manifest even though the dams of the F1 generation were not exposed to exercise stress during pregnancy and lactation. These findings suggest that the adverse effect of maternal exercise during pregnancy and lactation on fetal outcome in one generation is transferred to the subsequent generation.

Exercise induced changes in the energy expenditure of female Wistar rats

Changes in body weight and energy expenditure following exercise training was assessed in female Wistar rats. Rats were trained to swim in a tank filled with water for 2 hr everyday, 6 days a week. Changes in energy intake and body weight were recorded. The resting metabolic rate (RMR) was measured by indirect calorimetry and the capacity for non shivering thermogenesis (NST) was determined by measuring the stimulated oxygen consumption following a sc injection of norepinephrine (250 micrograms/kgbw). The RMR of exercised rats was 14% higher and the capacity for NST was 22% higher than that of sedentary rats. Energy intake of the exercised rats increased significantly while the body weights were maintained at levels comparable to that of the sedentary rats. Results indicate that body weight regulation is achieved by increasing food intake in response to the increased energy expenditure due to forced exercise as well as the stimulatory effect of exercise on RMR and NST.

[Value of ascitic lipids and sero-ascitic gradient of albumin in the differential diagnosis of ascites]

In order to compare its diagnostic value in the differentiation between malignant and hepatic ascites, we analysed the ascitic fluid concentrations of cholesterol (Ct) and triglycerides (Tg) and the serum-ascites albumin gradient (S-A alb grad) in 58 patients--forty one with chronic liver disease (CLD) and 17 with malignancy. In CLD group the mean values +/- SD for Ct (27.1 +/- 20.1 mg/dl), Tg (34.2 +/- 33.8 mg/dl) and S-A alb grad (1.9 +/- 0.6 g/dl) were significantly different from those obtained in malignant ascites (Ct 103.1 +/- 45.1 mg/dl; Tg 62.1 +/- 43.0 mg/dl; S-A alb grad 0.5 +/- 0.4 g/dl) (p less than 0.001 for all parameters). Application of the cutoff concentrations given in the literature revealed the following results: Ct-Sensitivity (Se) 82.4%, Specificity (Sp) 85.4%, Efficiency (E) 84.5%; Tg-Se 29.4%, Sp 95.1%, E 75.9%; S-A alb grad- Se 88.2%, Sp 97.6%, E 94.8%. The exclusion of the 4 patients with massive hepatic metastasis from malignant group by ultrasound or computer tomography gave an efficiency of 87.0% for Ct, 88.9% for Tg and 98.1% for S-A alb grad. We conclude that: 1) S-A alb grad is the best analysed parameter in the discrimination between malignant and hepatic ascites, 2) the combination with non-invasive imaging methods increases its diagnostic value.

Effect of two prostaglandin synthesis inhibitors, indomethacin and acetylsalicylic acid, on plasma ACTH and cortisol levels in man

The aim of this study was to investigate the possible role of prostaglandins (PG) in the control of the hypohtalamic-pituitary-adrenocortical axis in normal volunteers. Acute oral administration of 100 mg indomethacin (ID) or 1.5 g acetylsalicylic acid (ASA) did not alter ACTH and cortisol plasma levels. Administration of 300 mg daily ID for 4 days delayed the onset, but increased the magnitude, of the response of ACTH to insulin hypoglycaemia, while it blunted the cortisol response. Administration of 3.2 g ASA daily depressed ACTH response to hypoglycaemia leaving the cortisol response unchanged, except for a 15 min delay in onset. These results are interpreted assuming that ID and ASA chiefly acted at the pituitary and hypothalamic level, respectively, and that ID, but not ASA, interfered with adrenocortical cortisol production. Our findings support the concept, based on animal studies, that PG enhance hypothalamic CRF release and adrenocortical steroidogenesis and may restrain ACTH secretion in the pituitary.