Autophagy-Mediated Exosomes as Immunomodulators of Natural Killer Cells in Pancreatic Cancer Microenvironment

Pancreas ductal adenocarcinoma is a highly aggressive cancer with an incredible poor lifespan. Different chemotherapeutic agents' schemes have been tested along the years without significant success. Furthermore, immunotherapy also fails to cope with the disease, even in combination with other standard approaches. Autophagy stands out as a chemoresistance mechanism and is also becoming relevant as responsible for the inefficacy of immunotherapy. In this complex scenario, exosomes have emerged as a new key player in tumor environment. Exosomes act as messengers among tumor cells, including tumor microenvironment immune cells. For instance, tumor-derived exosomes are capable of generating a tolerogenic microenvironment, which in turns conditions the immune system behavior. But also, immune cells-derived exosomes, under non-tolerogenic conditions, induce tumor suppression, although they are able to promote chemoresistance. In that way, NK cells are well known key regulators of carcinogenesis and the inhibition of their function is detrimental for tumor suppression. Additionally, increasing evidence suggests a crosstalk between exosome biogenesis and the autophagy pathway. This mini review has the intention to summarize the available data in the complex relationships between the autophagy pathway and the broad spectrum of exosomes subpopulations in pancreatic cancer, with focus on the NK cells response.

Autochthonous Chagas disease in the southern United States: A case report of suspected residential and military exposures

Chagas disease is a parasitic infection that can result in a progressive dilated cardiomyopathy. Here, we present the epidemiologic details of a suspected locally acquired transmission case originating from the southern United States. This is the first published report of Chagas disease in a young, healthy United States veteran with repeat triatomine exposures in Arizona. Military personnel and Arizona residents should be aware of their Chagas disease transmission risks.

Sylvatic Transmission of Trypanosoma cruzi Among Domestic and Wildlife Reservoirs in Texas, USA: A Review of the Historical Literature

Chagas disease (Trypanosoma cruzi infection) is one of the most important neglected tropical diseases affecting the Americas. The transmission dynamic of this parasite is a complicated process that involves three genera of Triatominae subfamily and over 100 known mammalian reservoirs composed of domestic, peridomestic and wildlife species. Understanding the complex relationship between vector species and mammalian hosts is important for preventing transmission to humans. We performed a historical literature review to assess the disease burden in the Texas wildlife and domestic animal population. Reports of sylvatic transmission in Texas date back to the 1940s. We found that up to 23 species can serve as reservoirs for T. cruzi in the state with wood rats, raccoons, and wild and domestic canine species most frequently reported as positive for the parasite. We finish with a discussion of the current research gaps, implications for high-risk populations and future directions for research.

Genetic inactivation of the pancreatitis-inducible gene Nupr1 impairs PanIN formation by modulating Kras(G12D)-induced senescence

Nuclear protein 1 (Nupr1), a small chromatin protein, has a critical role in cancer development, progression and resistance to therapy. Previously, we had demonstrated that Nupr1 cooperates with Kras^G12D to induce pancreas intraepithelial neoplasias (PanIN) formation and pancreatic ductal adenocarcinoma development in mice. However, the molecular mechanisms by which Nupr1 influences Kras-mediated preneoplastic growth remain to be fully characterized. In the current study, we report evidence supporting a role for Nupr1 as a gene modifier of Kras^G12D-induced senescence, which must be overcome to promote PanIN formation. We found that genetic inactivation of Nupr1 in mice impairs Kras-induced PanIN, leading to an increase in β-galactosidase-positive cells and an upregulation of surrogate marker genes for senescence. More importantly, both of these cellular and molecular changes are recapitulated by the results of mechanistic experiments using RNAi-based inactivation of Nupr1 in human pancreatic cancer cell models. In addition, the senescent phenotype, which results from Nupr1 inactivation, is accompanied by activation of the FoxO3a-Skp2-p27^Kip1-pRb-E2F pathway in vivo and in vitro. Thus, combined, these results show, for the first time, that Nupr1 aids oncogenic Kras to bypass senescence in a manner that cooperatively promotes PanIN formation. Besides its mechanistic importance, this new knowledge bears medical relevance as it delineates early pathobiological events that may be targeted in the future as a means to interfere with the formation of preneoplastic lesions early during pancreatic carcinogenesis.

First report on sexually transmitted infections among trans (male to female transvestites, transsexuals, or transgender) and male sex workers in Argentina: high HIV, HPV, HBV, and syphilis prevalence

OBJECTIVES

Due to the scarce data on the prevalence of sexually transmitted infections (STIs) among male-to-female trans-sex workers (TSW) and male sex workers (MSW) in Argentina, the present study aimed to estimate the incidence of human immunodeficiency virus (HIV), and the prevalence of HIV, hepatitis B virus (HBV), hepatitis C virus (HCV), and Treponema pallidum. Human papillomavirus (HPV) and Chlamydia trachomatis infections were tested among TSW.

METHODS

Two hundred and seventy-three TSW and 114 MSW were recruited by nongovernmental organizations. HIV incidence was estimated by STARHS (serologic testing algorithm for recent HIV seroconversion). HPV and C. trachomatis infections were tested in anal cells from TSW.

RESULTS

TSW showed significantly higher prevalences of HIV (34.1 vs. 11.4%), HBV (40.2 vs. 22.0%), and T. pallidum (50.4 vs. 20.4%) than MSW. TSW tested positive for HPV in 111/114 cases and for C. trachomatis in 4/80 cases. Investigation of HBV, HCV, HIV, and T. pallidum co-infections showed that 72% of TSW and 39% of MSW had at least one STI. T. pallidum was the most frequent mono-infection. The estimated HIV incidence was 10.7 per 100 person-years (95% confidence interval (CI) 3.8-17.7) for TSW and 2.3 per 100 person-years (95% CI 0-6.7) for MSW.

CONCLUSIONS

The high prevalence of STIs and the high incidence of HIV demonstrate the great vulnerability of these high-risk populations and indicate the urgent need for preventive strategies on intervention and facilitation of access to healthcare programs.

Human papilloma virus genotype diversity of anal infection among trans (male to female transvestites, transsexuals or transgender) sex workers in Argentina

BACKGROUND

Reports on the prevalence and genotypes of HPV among trans (male to female transvestites, transsexuals or transgender) sex workers (TSW) are scarce in the literature.

OBJECTIVES

The aim of the study was to determine the infecting HPV genotypes among TSW in Argentina.

STUDY DESIGN

119 TSW were recruited. Anal cells were self collected with a cytobrush. HPV DNA detection was carried out by PCR and genotyping was performed by RLB.

RESULTS

HPV prevalence was 97.4%. 103/111 HPV positive samples were genotyped. High risk genotypes were detected in 82.5%. Two or more coinfecting HPV genotypes were found in 70.9%. One case showed up to 10 different coinfecting types. The number of genotypes was not related to condom usage. Infection rates were similar for HIV positive (100%) and HIV negative (95.8%) participants. However, 18.8% of HIV negative had 4-9 different genotypes, while among HIV positive this percentage raised to 46.2% (p=0.006). Prevalence of high risk genotypes and the frequency of each high risk type were similar between HIV positive and HIV negative groups. According to the participants' answers HIV status showed no association with condom usage.

CONCLUSIONS

The high HPV prevalence, the coinfection with multiple genotypes and the high frequency of high risk genotypes detected, together with a situation of extreme social marginalization, discrimination and stigmatization make this population to be of extreme vulnerability.

Centrifugation improves the detection of HIV-1 p24 antigen in plasma from children born to mothers infected with HIV-1

Detection of HIV proteins and/or nucleic acids is necessary for the diagnosis of perinatal HIV infection. Despite its low sensitivity, detection of p24 antigen in plasma is a simple and economic method for the diagnosis of HIV in exposed children. The aim of this study was to improve the sensitivity of detection of p24 using centrifugation of plasma. Forty-seven selected stored samples from 37 children (23 infected, 14 uninfected, median age of 137 days) were examined. Plasma samples (volume 0.3-1.5 ml) were defrosted, centrifuged at 23,500 x g at 4 degrees C for 60 min and determination of p24 was carried out in the resuspended pellet (0.12 ml). In 32 plasma samples from infected children, p24 was found originally in 6 (18.7%) and resulted positive in 24 (75%) pellets. When only one sample per child was considered, sensitivity was significantly higher in pellets, 3/23 uncentrifuged plasma samples and 15/23 pellets (McNemar Test, p<0.001). Specificity was 100%. The absorbance/cut-off ratio was always higher in the pellets from positive children (p=0.028). Plasma samples with volumes of 1 ml or more achieved a higher sensitivity (91.7% vs. 36.4%, p=0.009). Centrifugation of plasma samples prior to determination of p24 in pediatric patients resulted in a significant increase in sensitivity.

Development of compensatory hepatic hyperplasia in mice carrying the hepatocellular carcinoma ES12a

In a previous paper we reported that the presence of the hepatocellular carcinoma SS1K in host mice resulted in an earlier appearance of the hepatocyte mitotic peak during liver regeneration after a partial hepatectomy as well as in an increase in the amplitude of that mitotic wave. In the present work we analyse the effect of another hepatocellular carcinoma, the ES12a (HCES12a). Adult male mice of the C3H/S strain standardised for circadian-periodicity analysis, were used. One group received a subcutaneous graft of the HCES12a tumor, while another group served as control. Fifteen days later, all animals were submitted to a partial (70%) hepatectomy at 10:00 h and beginning at 16:00 h lots of between 5 and 9 host and control animals each were sacrificed at 4 h intervals until 16:00 h on the third day thereafter. All mice were injected with 2 microg/g colchicine 4 hrs before killing, and samples of livers were processed for hematoxylin-eosin staining. We determined the hepatocyte mitotic index for each animal and the mean value +/- the standard error of the mean for each lot. The peak of mitotic activity in the tumor-bearing animals took place four hours earlier than in control mice but the average values of hepatocytic mitotic activity were similar in both groups

Effect of partial and sham hepatectomy on the growth of a hepatocellular carcinoma

We examined the effect of partial hepatectomy on the proliferation of hepatoma ES12a grafted into C3H/S mice compared to tumor growth in sham-hepatectomized controls. The animals were sacrificed every 4 hrs during three days from the 6th to the 78th h following each type of surgery. Unoperated tumor-bearing mice were likewise killed as controls, but only during one complete circadian period. All animals received 2 microg of colchicine per g of body weight intraperitoneally 4 hrs before decapitation. Measurement of mitotic indices in hematoxylineosin-stained tumor samples revealed a decrease in proliferation and a modification of the diurnal mitotic-activity profile in the hepatectomized and sham-operated animals from the first day after surgery. These differences persisted by the third postoperative day only in the hepatectomized animals. Thus, although surgical stress may initially affect tumor growth, the latter results must be the effect of the influence of the hepatic regeneration.

Studies on semduramicin and nutritional responses: 3. Electrolyte balance

Four experiments were conducted to determine whether fluctuations in dietary electrolyte level (milliequivalents Na+K-Cl per kilogram) or different dietary sodium chloride levels would affect performance, water intake, or excreta moisture of chickens fed semduramicin vs nonmedicated controls. In all experiments, male commercial broiler chicks were used, and all diets were fed with and without 25 mg semduramicin/kg diet. The basal diets were based on corn, soybean meal, and poultry oil. Experiments 1, 3, and 4 were conducted using male broiler chicks in battery brooders to 18 d of age. In Experiment 1, six electrolyte levels were fed [basal (0.2% Na, 0.33% Cl, 1.10% K); basal plus 0.1% Na (from sodium chloride); basal plus 0.1% K (from potassium chloride); basal plus 0.2% Na (from sodium carbonate); basal plus 0.34% K (from potassium chloride); basal plus 0.15% Cl (from ammonium chloride)]. There were no significant changes in BW gain, feed consumption, or feed conversion ratio caused by any dietary treatment. Water consumption was not affected by the inclusion of Na, Cl, K, or electrolyte levels, but excreta moisture was affected. The highest and lowest excreta moisture levels came from chicks fed the lowest chloride levels. There were no significant dietary effects on serum Na, Cl, or K by dietary electrolytes or semduramicin. Experiment 2 was conducted with triplicate floor pens of 33 male broilers each for 42 d with four electrolyte levels [basal (0.2% Na, 0.34% Cl, 1.03% K); basal plus 0.1% Na (from sodium carbonate); basal plus 0.1% Cl (from ammonium chloride); basal plus 0.18% K (from potassium carbonate)]. Increasing electrolyte level had a significant effect on BW gain at 35 d but not at 42 d [mainly because of differences in K (1.943 kg at 35 d) vs Cl (2.013 kg at 35 d)]. At 42 d, there were no differences in growth because of N, K, Cl, or semduramicin. Potassium supplementation caused a significant increase in litter moisture (P = 0.031). Semduramicin did not affect litter moisture (P = 0.892), nor were there significant semduramicin interactions with Na, K, Cl, or semduramicin. The basal diets in Experiments 3 and 4 were identical to the basal diet in Experiment 1 except there was no sodium chloride added. The diets fed in Experiment 3 contained 0, 0.1, 0.2, 0.3, or 0.4% added sodium chloride. The diets fed in Experiment 4 contained 0.1, 0.3, 0.5, 0.7, and 0.9% added sodium chloride. The results of Experiments 3 and 4 show that about 0.4% added sodium chloride is necessary to achieve maximum growth and feed conversion. It is clear that semduramicin had no significant effect upon the variation observed in any of the variables measured.

The Caco-2 cell culture system can be used as a model to study food iron availability

To assess the usefulness of the Caco-2 cell culture system as a model to study the availability of dietary iron, preliminary experiments were performed to determine the optimal conditions for iron uptake and transport. Iron uptake of radioactive ferrous sulfate was optimal at pH 5.5 using a 2:1 molar ratio of ascorbic acid to iron and a 1-h incubation time. Under these experimental conditions, we studied the effect on iron uptake of adding supernatants from homogenates of different meat sources, soybean protein isolates, egg albumen and bovine serum albumin. Iron uptake was 6.3 +/- 1.7% from meat, which was significantly greater (P < 0.001) than the values of 1.2 +/- 0.3% from soybean protein, 1.3 +/- 0.3% from egg albumen and 0.8 +/- 0.1% from bovine serum albumin. Iron uptake was also significantly higher from digested meat samples than from undigested meat when the protein concentration was equalized. Measurements of iron uptake and protein concentration from fractions obtained after preparative isoelectric focusing of meat and soybean protein extracts showed two peaks of higher protein concentration and iron uptake in meat, apparently not found in soybean protein, that contained the factor(s) responsible for the higher iron uptake by the cells. In view of these observed similarities with iron absorption studies in humans, we conclude that the Caco-2 cell culture system is a useful in vitro model to study food iron availability.

Long-range effects on the retinal chromophore of bacteriorhodopsin caused by surface carboxyl group modification

Carboxyl groups of bacteriorhodopsin (bR) that are modified by 1-ethyl-3-[3-(trimethylamino)-propyl]carbodiimide (ETC) have been identified. Reaction of deionized purple membrane with a 400-fold molar excess of ETC or [14C]ETC for 1 h at 0 degree C incorporates about 3.5 mol of ETC/mol of bR. Proteinase K cleavage of ETC-modified bacterioopsin (bO) produced small 14C-labeled peptides. Amino acid sequence analysis showed three major ETC-modified residues: Glu 234, Asp 38, and Glu 74. Proteolysis of purple membrane with papain removes the ETC site at Glu 234. Treatment of ETC-modified, papain-cleaved purple membrane with hydroxylamine removes half of the remaining ETC label. Subsequent cleavage with chymotrypsin, followed by amino acid sequence analysis, revealed that most of the remaining label was at Glu 74. bR modified by ETC primarily at Glu 74 displays two alterations in the retinal chromophore, located in the membrane interior at a distance more than 2 nm away from the modified carboxyl group. (1) The acid-induced purple-to-blue transition undergoes a shift in apparent pK from 3.2 to 2.3. (2) The second-order rate constant for chromophore regeneration from bO and retinal is diminished from 3600 to 1700 M-1 s-1 in membrane sheets. Most of the shift in the pK of the purple-to-blue transition can be explained by the quaternary ammonium ion of ETC attached to Glu 74 overlapping the postulated location of the guanidinium group of Arg 82.(ABSTRACT TRUNCATED AT 250 WORDS)