Aryl-hydrocarbon receptor-interacting protein regulates tumorigenic and metastatic properties of colorectal cancer cells driving liver metastasis.

BACKGROUND: Liver metastasis is the primary cause of colorectal cancer (CRC)-associated death. Aryl-hydrocarbon receptor-interacting protein (AIP), a putative positive intermediary in aryl-hydrocarbon receptor-mediated signalling, is overexpressed in highly metastatic human KM12SM CRC cells and other highly metastatic CRC cells. METHODS: Meta-analysis and immunohistochemistry were used to assess the relevance of AIP. Cellular functions and signalling mechanisms mediated by AIP were assessed by gain-of-function experiments and in vitro and in vivo experiments. RESULTS: A significant association of high AIP expression with poor CRC patients' survival was observed. Gain-of-function and quantitative proteomics experiments demonstrated that AIP increased tumorigenic and metastatic properties of isogenic KM12C (poorly metastatic) and KM12SM (highly metastatic to the liver) CRC cells. AIP overexpression dysregulated epithelial-to-mesenchymal (EMT) markers and induced several transcription factors and Cadherin-17 activation. The former induced the signalling activation of AKT, SRC and JNK kinases to increase adhesion, migration and invasion of CRC cells. In vivo, AIP expressing KM12 cells induced tumour growth and liver metastasis. Furthermore, KM12C (poorly metastatic) cells ectopically expressing AIP became metastatic to the liver. CONCLUSIONS: Our data reveal new roles for AIP in regulating proteins associated with cancer and metastasis to induce tumorigenic and metastatic properties in colon cancer cells driving liver metastasis.

Seroreactivity Against Tyrosine Phosphatase PTPRN Links Type 2 Diabetes and Colorectal Cancer and Identifies a Potential Diagnostic and Therapeutic Target.

Colorectal cancer (CRC) and diabetes are two of the most prevalent chronic diseases worldwide with dysregulated receptor tyrosine kinase signaling and strong co-occurrence correlation. Plasma autoantibodies represent a promising early diagnostic marker for both diseases before symptoms appear. In this study, we explore the value of autoantibodies against receptor-type tyrosine-protein phosphatase-like N (PTPRN; full-length or selected domains) as diagnostic markers using a cohort of individuals with type 2 diabetes (T2D), CRC, or both diseases or healthy individuals. We show that PTPRN autoantibody levels in plasma discriminated between patients with T2D with and without CRC. Consistently, high PTPRN expression correlated with decreased survival of patients with CRC. Mechanistically, PTPRN depletion significantly reduced invasiveness of CRC cells in vitro and liver homing and metastasis in vivo by means of a dysregulation of the epithelial-mesenchymal transition and a decrease of the insulin receptor signaling pathway. Therefore, PTPRN autoantibodies may represent a particularly helpful marker for the stratification of patients with T2D at high risk of developing CRC. Consistent with the critical role played by tyrosine kinases in diabetes and tumor biology, we provide evidence that tyrosine phosphatases such as PTPRN may hold potential as therapeutic targets in patients with CRC.

Intake of high saturated-fat diets disturbs steroidogenesis, lipid metabolism and development of obese-swine conceptuses from early-pregnancy stages.

The current study indicates that life-long intake, from early-life, of an obesogenic diet with high saturated-fat (HSF) content induces dyslipidemia (high plasma concentrations of triglycerides in concurrence with low concentrations of HDL-cholesterol) in obese swine with leptin resistance (Iberian sows). In case of pregnancy, ovarian features (ovulatory efficiency and luteal steroidogenesis) of sows fed with HSF are not affected but embryo features are affected at so early stages like 28 days of pregnancy (first quarter), although embryo viability was still not affected. In this way, offspring from HSF sows showed a higher incidence of alterations in their developmental trajectory, mainly due to a higher incidence of growth retardation, in their steroidogenic activity and in their availability of triglycerides and cholesterol. In conclusion, the results obtained in the present study illustrate the deleterious effects of maternal dyslipidemia, induced by the intake of HSF diets, on the oestradiol secretion of the conceptuses at early-pregnancy stages and, thus, on their developmental and metabolic features. This article is part of a Special Issue entitled 'Pregnancy and steroids'.

Effect of an obesogenic diet during the juvenile period on growth pattern, fatness and metabolic, cardiovascular and reproductive features of Swine with obesity/leptin resistance.

The objective of this study was to determine, in a female swine model of leptin resistance (Iberian pig), the effect of an obesogenic diet, with high saturated fat content, during the juvenile period, on the appearance of early obesity and its possible effects on metabolic syndrome-related parameters and reproductive features (puberty attainment). Thus, from 130 to 245 days-old, seven Iberian gilts had ad libitum access to food enriched with saturated fat whilst six females acted as controls and had ad libitum access to a commercial maintenance diet. Results showed that a high fat intake-level during the juvenile period induces early obesity with lower body weight and size but a higher body fat-content. Such obesity was related with impairments of glucose regulation predisposing for insulin resistance, but also with an earlier onset of puberty. However, there were no signs of hypertriglyceridemia and hypertension; the gilts diminish their intake level and modify their metabolic features by increasing insulin secretion. In conclusion, Iberian gilts freely eating saturated fat diets during the juvenile period have the prodrome of metabolic syndrome but, during their juvenile period, are still able to develop an adaptive response to the diet.

Ovulation, implantation and placentation in females with obesity and metabolic disorders: life in the balance.

Obesity due to endocrine and metabolic disorders causing dysfunctions of appetite-regulating pathways and energy balance is an increasingly concerning issue. Such form of obesity is mainly caused by the failure of elevated levels of the hormone leptin (LEP) to suppress feeding and mediate weight loss; the syndrome, caused by disruptions of signal transduction processes at the level of leptin receptors (LEPR), has been named as leptin resistance. Alterations in genes coding for LEPR and other hypothalamic factors in obese individuals have been related to low rates of pregnancies and deliveries. Fertility depends mainly on the success of processes involving ovulation, fertilization, implantation, placentation and embryo development; processes that seem to be affected in obese females. However, mechanistical research in human beings is very difficult to undertake, especially in reproductive issues, for both technical and ethical reasons. Thus, investigation is usually taken on animal models. Most of the studies have been carried out in mice, in which mutations in LEP and LEPR genes cause severe obese phenotypes (Leprob/ob and Leprdb/db mouse); in addition, such genotypes are infertile. However, total loss of LEPR function by monogenic disorders in humans, unlike mice, are really scarce. Functional alterations by LEPR gene polymorphisms are more common; the same has been found in the swine, an animal model very close to human. This review outlines, from results of translational animal research and clinical studies, the factors, mechanisms and pathways involved in the reproductive failures of individuals with metabolic disorders during the critical period from ovulation to completion of placentation and early-embryo development.

The effects of age and reproductive status on blood parameters of carbohydrate and lipid metabolism in Iberian obese sows.

The effects of age and reproductive status on carbohydrate and lipid metabolism of Iberian sows reared in an intensive management system were examined. These animals, with age, are predisposed to hyperglycaemia and dyslipidemia which may develop in response to nutritional challenges during lactation. At weaning, high levels of glucose, triglycerides and low-density lipoproteins cholesterol (LDL-c) with low high-density lipoproteins cholesterol (HDL-c) are indicative of insulin resistance.

Developmental competence of antral follicles and their oocytes after gonadotrophin treatment of sows with gene polymorphisms for leptin and melanocortin receptors (Iberian pig).

PURPOSE: To evaluate possible differences in follicle and oocyte developmental competence after gonadotrophin treatment in sows of obese and lean genotypes. METHODS: Follicle dynamics, ovulation rate and oocyte developmental competence to embryo were compared between females, of obese (n = 7) and lean genotypes (n = 10), treated with 1,250 I.U. of eCG and 500 I.U. of hCG. RESULTS: The obese genotype showed lower numbers of follicles growing to preovulatory stages (12.4 ± 1.8 vs 18.6 ± 1.0, P < 0.05), of corpora lutea (16.0 ± 0.9 vs 23.5 ± 0.9, P < 0.05), and of recovered oocytes/embryos (8.0 ± 1.3 vs 12.9 ± 0.9, P < 0.05). Thereafter, embryo viability rates also decreased when compared to lean genotypes (62.5 vs 77.6%, P < 0.05). DISCUSSION: To our knowledge, this is the first study analyzing the effect of obese genotypes on the ovarian response to exogenous gonadotrophins in a non-rodent animal model, the pig. A lower efficiency of gonadotrophin treatments for stimulation of follicle development and induction of ovulation was observed.

Phenotypic characterization by high-resolution three-dimensional magnetic resonance imaging evidences differential effects of embryo genotype on intrauterine growth retardation in NOS3-deficient mice.

The Nos3-knockout mouse, deficient for endothelial constitutive nitric oxide synthase (NOS3), is affected by a reduction in the number and weight of the embryos and constitutes a good model for some features of preeclampsia and intrauterine growth retardation (IUGR). Deficiencies in conceptus growth and survival may result from factors inherent in the embryo itself or from deficiencies in uterine function. In the current study, we aimed to determine the effects of embryonic genotype independently of maternal genotype, which can affect uterine environment. Therefore, by using magnetic resonance imaging (MRI), we characterized the phenotypes of NOS3-defective (Nos3(-/-); n = 6), normal wild-type (Nos3(+/+); n = 5), and heterozygous (Nos3(+/-); n = 16) mouse fetuses. All of them were littermates obtained by breeding heterozygous mice (Nos3(+/-)); therefore, the maternal genotype was the same for all the fetuses. At Day 13.5 (i.e., Theiler stage TS 21-22), females were anesthetized and scanned with three-dimensional MRI. Analysis of the different measurements of the embryos and the gestational annexes showed no significant differences between Nos3(+/+) and Nos3(+/-); however, there was a trend toward larger sizes in Nos3(+/+), and values in Nos3(-/-) were significantly smaller than in Nos3(+/+) and Nos3(+/-). The reduction in the crown-rump length of Nos3(-/-) reached 12% when compared to Nos3(+/+) (P < 0.05); the effect was higher for head measurements (16% for occipito-snout length and biparietal diameter, P < 0.05 for both) and trunk diameter (17%, P < 0.05). Overall, the maximum area of fetuses in longitudinal planes decreased 27% (P < 0.05) when comparing Nos3(-/-) to wild-type Nos3(+/+). Finally, Nos3(-/-) showed a reduction of 29% in the maximum thickness of the placenta, which may be related to the appearance of IUGR due to compromised nutritional delivery to the fetus.

The effect of embryo and maternal genotypes on prolificacy, intrauterine growth retardation and postnatal development of Nos3-knockout mice.

Mice deficient for endothelial nitric oxide synthase (NOS3(-/-)) may represent a good model for studying embryo loss and intrauterine growth retardation caused by vascular deficiencies. We determined the effects of embryo genotype (homozygous vs. heterozygous descendants with paternal or maternal source of the non-functional NOS3 allele) and maternal environment (NOS3(-/-) vs. wild-type NOS3(+/+) females) on the appearance of estrus, fertility and prolificacy rates and live weight in the first week of life as well as phenotypic characteristics of offspring during the postnatal period. The results indicated that pregnancy outcomes and postnatal development of NOS3(-/-) mice seem to be related to deficiencies in fetal programming mainly determined by maternal genotype.

Ectopic Meis1 expression in the mouse limb bud alters P-D patterning in a Pbx1-independent manner.

During limb development, expression of the TALE homeobox transcription factor Meis1 is activated by retinoic acid in the proximal-most limb bud regions, which give rise to the upper forelimb and hindlimb. Early subdivision of the limb bud into proximal Meis-positive and distal Meis-negative domains is necessary for correct proximo-distal (P-D) limb development in the chick, since ectopic Meis1 overexpression abolishes distal limb structures, produces a proximal shift of limb identities along the P-D axis, and proximalizes distal limb cell affinity properties. To determine whether Meis activity is also required for P-D limb specification in mammals, we generated transgenic mice ectopically expressing Meis1 in the distal limb mesenchyme under the control of the Msx2 promoter. Msx2:Meis1 transgenic mice display altered P-D patterning and shifted P-D Hox gene expression domains, similar to those previously described for the chicken. Meis proteins function in cooperation with PBX factors, another TALE homeodomain subfamily. Meis-Pbx interaction is required for nuclear localization of both proteins in cell culture, and is important for their DNA-binding and transactivation efficiency. During limb development, Pbx1 nuclear expression correlates with the Meis expression domain, and Pbx1 has been proposed as the main Meis partner in this context; however, we found that Pbx1 deficiency did not modify the limb phenotype of Msx2:Meis1 mice. Our results indicate a conserved role of Meis activity in P-D specification of the tetrapod limb and suggest that Pbx function in this context is either not required or is provided by partners other than Pbx1.

Progress toward "in vivo virtual histology" of ovarian follicles and corpora lutea by ultrasound biomicroscopy.

High-frequency ultrasound imaging (40 MHz; ultrasound biomicroscopy) provides reliable ex vivo visualization of cellular components both in follicles and corpora lutea. In the near future and after logical technical evolution it may be useful for in vivo intraoperative evaluation of ovaries in large mammals and humans.

The feasibility of ultrasound biomicroscopy for non-invasive and sequential assessment of ovarian features in rodents.

The current study assessed the usefulness of in vivo high frequency ultrasound imaging (ultrasound biomicroscopy, UBM) for dynamic study of the ovarian structures in laboratory rodents. UBM imaging was performed, by using a 40 MHz probe, in 12 C57BL/6J female mice and four Wistars female rats at breeding age and during different reproductive periods. UBM provided outstanding images of both follicles and corpora lutea in cycling and non-cycling rats and mice and was useful to evaluate the ovarian response after controlled ovarian stimulation in the mouse. Thus, UBM may be a very useful method for reproductive studies in rodents.

Disruption of the endothelial nitric oxide synthase gene affects ovulation, fertilization and early embryo survival in a knockout mouse model.

Two consecutive experiments determined whether disruption of the endothelial nitric oxide synthases (NOS) gene (Nos3) affects ovulation, fertilization, implantation, and embryo development. In the first trial, Nos3-knockout mice (groups Nos3(-/-)) and wild-type mice (groups Nos3(+/+)) showed significant differences in mean number of corpora lutea (9.7+/-1.2 in Nos3(-/-) versus 14.2+/-1.2 in Nos3(+/+); P<0.01), rate of anovulation (48.3+/-7.3% in Nos3(-/-) versus 29.7+/-6.3 in Nos3(+/+); P<0.05), total mean number of recovered oocytes/zygotes (4.0+/-1.1 in Nos3(-/-) versus 10.4+/-1.6 in Nos3(+/+); P<0.01), and non-fertilization rate (50.7 in Nos3(-/-) versus 3.3% in Nos3(+/+); P<0.001). In the second trial, implantation and early pregnancy losses in Nos3-knockout and wild-type dams were detected by real-time ultrasound imaging. The number of embryos reaching implantation was higher in Nos3(+/+) than in Nos3(-/-) mice (7.5+/-0.4 vs 4.0+/-0.4; P<0.005); thereafter, embryo losses were detected between days 8.5 and 13.5, in 62.5% of the Nos3-knockout dams and, at days 10.5 and 11.5, in 16.7% of the control females (P<0.005). Thus, NO and NOS3 deficiencies affect reproductive and developmental features in the Nos3-knockout mouse model.

Intrauterine growth retardation in endothelial nitric oxide synthase-deficient mice is established from early stages of pregnancy.

The current study aimed to determine effects of deficiencies in nitric oxide synthase (NOS) 3 on embryo and fetal development by in vivo, noninvasive, real-time ultrasonographic assessment of phenotypic changes in Nos3-knockout pregnant mice and their wild-type counterparts. From Day 4.5 of pregnancy onwards, embryonic vesicle diameters, crown-rump lengths, and trunk diameters were obtained by serial scanning of seven adult pregnant female mice, strain B6.129P2-Nos3(tm1Unc)/J, N9 generation backcrossing with C57BL/6J mice, homozygous for the disruption of the endothelial NOS gene (group Nos3(-/-)), and 12 pregnant, wild-type C57BL/6J mice (group Nos3(+/+)). All the measurements increased in both genotypes throughout gestation. However, embryo length and width were significantly larger in Nos3(+/+) than in Nos3(-/-) mice from Day 8.5, and both longitudinal and transverse diameters of the entire gestational sacs were larger in Nos3(+/+) mice from Day 10.5. Assessment of the relative growth of embryos/fetuses and gestational annexes showed different patterns among Nos3(-/-) and Nos3(+/+) mice. Throughout pregnancy, the distance between the external limit of the gestational sac and the embryo in Nos3(+/+) mice diminished in longitudinal sections, or remained unaffected in transverse sections. In Nos3(-/-) mice, there were significant increases (P < 0.005) in the differences between embryo and gestational vesicle measurements in both longitudinal and transversal curves from Days 5.5 to 14.5, but from Day 14.5 of pregnancy onward, the changes were not significant. The results demonstrate that the processes of fetal growth retardation in the Nos3(-/-) mice are established from early pregnancy stages.

Development of a transgenic mouse model susceptible to human coronavirus 229E.

Human coronavirus (HCoV) 229E is a group 1 coronavirus and is specific to humans. So far, no animal model is available to study the pathogenesis of infection by HCoV-229E. We show here that the expression of aminopeptidase N (APN, also termed CD13), the receptor for HCoV-229E, is required but not sufficient to confer susceptibility in vivo. HCoV-229E infection was facilitated by crossing APN transgenic mice into signal transducers and activators of transcription (Stat) 1 null mice and by adaptation of HCoV-229E to grow in primary APN transgenic, Stat1 null fibroblasts. Double transgenic mice allow the study of human coronavirus group 1 infections in an animal model, in particular, viral tropism, replication, recombination, and spread in an immunocompromised situation. Furthermore, these mice provide an important tool for the evaluation of biosafety and efficacy of coronavirus-based vectors.

Absence of CCR8 does not impair the response to ovalbumin-induced allergic airway disease.

Interaction of chemokines with their specific receptors results in tight control of leukocyte migration and positioning. CCR8 is a chemokine receptor expressed mainly in CD4(+) single-positive thymocytes and Th2 cells. We generated CCR8-deficient mice (CCR8(-/-)) to study the in vivo role of this receptor, and describe in this study the CCR8(-/-) mouse response in OVA-induced allergic airway disease using several models, including an adoptive transfer model and receptor-blocking experiments. All CCR8(-/-) mice developed a pathological response similar to that of wild-type animals with respect to bronchoalveolar lavage cell composition, peripheral blood and bone marrow eosinophilia, lung infiltrates, and Th2 cytokine levels in lung and serum. The results contrast with a recent report using one of the OVA-induced asthma models studied here. Similar immune responses were also observed in CCR8(-/-) and wild-type animals in a different model of ragweed allergen-induced peritoneal eosinophilic inflammation, with an equivalent number of eosinophils and analogous increased levels of Th2 cytokines in peritoneum and peripheral blood. Our results show that allergic diseases course without critical CCR8 participation, and suggest that further work is needed to unravel the in vivo role of CCR8 in Th2-mediated pathologies.