Development Of Early Lesions Research Articles

Early Endometriosis in Females Is Directed by Immune-Mediated Estrogen Receptor α and IL-6 Cross-Talk.

Endometriosis is a gynecological disease that negatively affects the health of 1 in 10 women. Although more information is known about late stage disease, the early initiation of endometriosis and lesion development is poorly understood. Herein, we use a uterine tissue transfer mouse model of endometriosis to examine early disease development and its dependence on estradiol (E2) and estrogen receptor (ER) α within 72 hours of disease initiation. Using wild-type and ERα knockout mice as hosts or donors, we find substantial infiltration of neutrophils and macrophages into the peritoneal cavity. Examining cell infiltration, lesion gene expression, and peritoneal fluid, we find that E2/ERα plays a minor role in early lesion development. Immune-mediated signaling predominates E2-mediated signaling, but 48 hours after the initiation of disease, a blunted interleukin (IL)-6-mediated response is found in developing lesions lacking ERα. Our data provide evidence that the early initiation of endometriosis is predominantly dependent on the immune system, whereas E2/ERα/IL-6-mediated cross-talk plays a partial role. These findings suggest there are two phases of endometriosis—an immune-dependent phase and a hormone-dependent phase, and that targeting the innate immune system could prevent lesion attachment in this susceptible population of women.

Early Development of Right Ventricular Ischemic Lesions in a Novel Large Animal Model of Acute Right Heart Failure in Chronic Thromboembolic Pulmonary Hypertension

BackgroundOur aim was to develop a model of acute right heart failure (ARHF) in the setting of pulmonary hypertension and to characterize acute right ventricular lesions that develop early after hemodynamic restoration. Methods and ResultsWe used a described piglet model of chronic pulmonary hypertension (cPH) induced by pulmonary artery occlusions. We induced ARHF in animals with cPH (ARHF-cPH group, n = 9) by volume loading and iterative acute pulmonary embolism until hemodynamic compromise followed by dobutamine infusion for hemodynamic restoration before sacrifice for right ventricular tissue evaluation. The median duration of ARHF before sacrifice was 162 (135–189) minutes. Although ventriculoarterial coupling (measured with multibeat pressure-volume loops) and stroke volume decreased after iterative pulmonary embolism and improved with dobutamine, relative pulmonary to systemic pressure increased by 2-fold and remained similarly increased with dobutamine. Circulating high-sensitivity troponin I increased after hemodynamic restoration. We found an increase in right ventricular subendocardial and subepicardial focal ischemic lesions and in expression of autophagy-related protein LC3-II (Western blot) in the ARHF-cPH group compared with the cPH (n = 5) and control (n = 5) groups. ConclusionsWe developed and phenotyped a novel large animal model of ARHF on cPH in which right ventricular ischemic lesions were observed early after hemodynamic restoration.

OP 20 Increased classical atherosclerotic risk factors in elderly women with decidual acute atherosis

Introduction Uteroplacental acute atherosis is a specific arterial lesion of pregnancy resembling early stages of atherosclerosis. Acute atherosis is frequent in pregnancies complicated by preeclampsia, which is associated with increased long-term maternal risk of atherosclerotic cardiovascular disease (CVD). Objectives We investigated if acute atherosis of the decidua basalis in pregnant women is associated with traditional risk factors for cardiovascular disease, including hypertension, hyperlipidemia, glucose intolerance, elevated CRP, age during pregnancy and prepregnancy body mass index. Materials and methods Women delivered by elective cesarean section ( n = 237; healthy pregnancies n = 94, preeclampsia n = 87, pregestational diabetes and gestational diabetes n = 39, diabetes with preeclampsia n = 17)) provided blood samples prior to caesarean section (cs) together with uteroplacental (decidua) tissue (by vacuum suction at cs) for acute atherosis diagnosis by a validated immunohistochemistry approach. Statistical analyses were performed with Mann–Whitney test. Results We found no associations between acute atherosis and traditional CV biomarkers within the groups of women with normotensive pregnancies, preeclampsia, diabetes or diabetes superimposed with preeclampsia. However, the oldest patient age quartile (36–43 years old) with acute atherosis had significantly increased levels of Low Density Lipoprotein and ApolipoproteinB (both p Acute atherosis was associated with elevated median early pregnancy systolic blood pressure ( p = 0.01) in the total cohort, but likely due to a large proportion of women with acute atherosis having preeclampsia (62.7%). Conclusion As increased levels of LDL and Apolipoprotein B are key events in the initiation of early atherosclerotic lesions, our results may point towards similar mechanisms in development of acute atherosis and early atherosclerotic lesions in the oldest age quartile of pregnancy.

Histomorphological Study of Gestational Trophoblastic Lesions in a Tertiary Medical Centre: A Prospective Study

Background: Gestational trophoblastic diseases(GTDs) consists of pregnancy related disorders ranging from benign Hydatidiform mole, Invasive mole to neoplastic conditions including Choriocarcinoma, Placental site trophoblastic tumor and Epitheloid trophoblastic tumor with varying potential for local invasion and metastasis. GTDs mimic growth pattern encountered in early normal placental development, nonmolar abortions and variety of nontrophoblastic lesions. Therefore an appreciation of different types of GTDs with its histomorphological manifestations are important for the confirmation of diagnosis. Thus the study was undertaken. Materials & methods: The material for the study comprised of products of conception specimens received in the Department of Pathology, J.J.M. Medical college, Davangere, India during the period of 2 years. Detailed gross examination was done before fixation and subsequent microscopic analysis was done. Results: 65 cases of GTDs were diagnosed in 495 cases of products of conception. 37 cases of complete mole, 27 cases of partial mole and one case of Invasive mole were diagnosed. Diffuse hydropic swelling of the villi, round smooth villous outline, circumferential trophoblastic proliferation and focal hydropic swelling of the villi, irregular scalloping outline of the enlarged villi, focal trophoblastic cell proliferation were characteristic features of complete & partial mole respectively. Histomorphological features were analysed in all the cases and compared with studies done by others. Conclusion: The classification and histomorphological analysis of GTDs are important elements for better understanding of the disease. Studies are needed to look for ancillary markers in distinguishing different types of GTDs and for predicting the prognosis. DOI: 10.21276/APALM.1193

JAK2V617F Promotes Atherosclerosis

Myeloproliferative disorder (MPD) patients are at high risk of atherothrombotic events including myocardial infarction and stroke. The somatic mutation (JAK2V617F) is commonly found in MPD patients and is associated with increased vascular risk. Moreover, the prevalence of JAK2V617F mutation is also significantly increased in non-MPD coronary artery disease (CAD) and peripheral artery disease (PAD) patients compared to the general population. Our goal was to investigate potential mechanisms of accelerated atherothrombosis using a JAK2V617F mouse model.Subletahlly irradiated Ldlr-/- mice were transplanted with bone marrow cells from wild type (WT) or Mx1-Cre/Jak2V617F (Jak2VF) mice and fed a high fat high cholesterol Western type diet (WTD). After 7 weeks of WTD Jak2VFmice had sustained neutrophilia, monocytosis and erythrocytosis; despite lower plasma cholesterol levels they showed ~1.6 fold larger atherosclerotic lesions in the aortic root (p=0.003) and accelerated carotid artery thrombosis (FeCl3 injury). After 12 weeks of WTD feeding, lesion area was only increased 1.3-fold compared to controls but showed features of plaque instability (increased necrotic core area). Early lesions (7 weeks) displayed significantly increased neutrophils (p=0.05, n=7) but not Mac 3+ macrophages. The increased neutrophil infiltration in Jak2VF mice correlated with atherosclerotic lesion size (p=0.001, r=0.78), suggesting a critical role of neutrophils in early atherogenesis. Advanced lesions (12 weeks) also showed significantly increased neutrophil (p=0.001) and macrophage (p=0.05) infiltration. No difference in CD3+ T cells or CD41+ platelet infiltration was observed at either time-point. In addition, five out of nine Jak2VF mice had prominent iron deposition (Prussian blue) and RBC marker Ter-119 staining in advanced atherosclerotic lesions (p<0.05). RBC marker Ter-119 co-localized with Mac-3(+) macrophages surrounding necrotic cores, indicating erythrophagocytosis and plaque instability.In summary, the Jak2V617F mutation promotes early atherosclerotic lesion development and plaque instability in advanced lesions. Neutrophil infiltration appears to be an important contributor to both early lesion development and necrotic core formation. These studies also suggest a novel role for RBC infiltration, iron deposition and erythrophagocytosis in advanced lesional necrotic core formation in JAK2V617F mice. DisclosuresLevine:Novartis: Consultancy; Qiagen: Membership on an entity's Board of Directors or advisory committees. Tall:Amgen: Consultancy; CSL Behring: Consultancy.

Haploinsufficiency in tumor predisposition syndromes: altered genomic transcription in morphologically normal cells heterozygous for VHL or TSC mutation.

Tumor suppressor genes and their effector pathways have been identified for many dominantly heritable cancers, enabling efforts to intervene early in the course of disease. Our approach on the subject of early intervention was to investigate gene expression patterns of morphologically normal one-hit cells before they become hemizygous or homozygous for the inherited mutant gene which is usually required for tumor formation. Here, we studied histologically non-transformed renal epithelial cells from patients with inherited disorders that predispose to renal tumors, including von Hippel-Lindau (VHL) disease and Tuberous Sclerosis (TSC). As controls, we studied histologically normal cells from non-cancerous renal epithelium of patients with sporadic clear cell renal cell carcinoma (ccRCC). Gene expression analyses of VHLmut/wt or TSC1/2mut/wt versus wild-type (WT) cells revealed transcriptomic alterations previously implicated in the transition to precancerous renal lesions. For example, the gene expression changes in VHLmut/wt cells were consistent with activation of the hypoxia response, associated, in part, with the Warburg effect. Knockdown of any remaining VHL mRNA using shRNA induced secondary expression changes, such as activation of NF?B and interferon pathways, that are fundamentally important in the development of RCC. We posit that this is a general pattern of hereditary cancer predisposition, wherein haploinsufficiency for VHL or TSC1/2, or potentially other tumor susceptibility genes, is sufficient to promote development of early lesions, while cancer results from inactivation of the remaining normal allele. The gene expression changes identified here are related to the metabolic basis of renal cancer and may constitute suitable targets for early intervention.

Cardiovascular Complications of Rheumatoid Arthritis: Prevalence and Pathogenesis

Rheumatoid arthritis (RA) is a chronic inflammatory disease associated with high risk of cardiovascular events. Among main causes of death in RA are: myocardial infarction, cerebrovascular accident, sudden cardiac death, which are determined by the early development and rapid progression of atherosclerotic vascular lesions. According to studies high risk of cardiovascular events is not explained by only classical risk factors. It is assumed that there are additional mechanisms of development of adverse outcomes such as systemic inflammation, increased arterial stiffness, and endothelial dysfunction. In this literature review we present various risk factors of cardiovascular events in patients with RA and their relation to RA pathogenesis.

Artemisinin inhibits monocyte adhesion to HUVECs through the NF-κB and MAPK pathways in vitro

The adhesion of monocytes to human umbilical vein endothelial cells (HUVECs) plays a crucial role in the initiation of atherosclerosis. Intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) are two important molecules involved in the adhesion of monocytes to HUVECs. Previous studies have suggested that artemisinin, apart from an anti-malarial agent, also has other effects. In the present study, we found that artemisinin significantly decreased the adhesion of monocytes to tumor necrosis factor-α (TNF-α)-stimulated HUVECs in a dose-dependent manner and suppressed the mRNA and protein level of ICAM-1 and VCAM-1 in the TNF-α-stimulated HUVECs. In addition, the nuclear factor-κB (NF-κB) inhibitor, Bay 11-7082, and mitogen-activated protein kinase (MAPK) inhibitors (SB203580 and U0126) respectively reduced the adhesion of monocytes to TNF-α-stimulated HUVECs, and suppressed ICAM-1 and VCAM-1 expression in TNF-α stimulated HUVECs. Moreover, artemisinin impeded the activation of the NF-κB and MAPK signaling pathways. Furthermore, Bay 11-7082 significantly decreased the phosphorylation of levels extracellular signal-regulated protein kinase (ERK)1/2, p38 and c-Jun N-terminal kinase (JNK). Taken together, the findings of our study indicated that artemisinin blocked monocyte adhesion to TNF-α-stimulated to HUVECs by downregulating ICAM-1 and VCAM-1 expression in the TNF-α-stimulated HUVECs. Artemisinin may thus have potential for use in the protection against the early development of atherosclerotic lesions.

Nitric Oxide is a Central Common Metabolite in Vascular Dysfunction Associated with Diseases of Human Pregnancy.

Preeclampsia (PE), gestational diabetes mellitus (GDM), and maternal supraphysiological hypercholesterolaemia (MSPH) are pregnancy-related conditions that cause metabolic disruptions leading to alterations of the mother, fetus and neonate health. These syndromes result in fetoplacental vascular dysfunction, where nitric oxide (NO) plays a crucial role. PE characterizes by abnormal increase in the placental blood pressure and a negative correlation between NO level and fetal weight, suggesting that increased NO level and oxidative stress could be involved. GDM courses with macrosomia along with altered function of the fetal cardiovascular system and fetoplacental vasculature. Even when NO synthesis in the fetoplacental vasculature is increased, NO bioavailability is reduced due to the higher oxidative stress seen in this disease. In MSPH, there is an early development of atherosclerotic lesions in fetal and newborn arteries, altered function of the fetoplacental vasculature, and higher markers of oxidative stress in fetal blood and placenta, thus, vascular alterations related with NO metabolism occur as a consequence of this syndrome. Potential mechanisms of altered NO synthesis and bioavailability result from transcriptional and post-translational NO synthases (NOS) modulation, including phosphorylation/dephosphorylation cycles, coupling/uncoupling of NOS, tetrahydrobiopterin bioavailability, calcium/calmodulin-NOS and caveolin-1-NOS interaction. Additionally, oxidative stress also plays a role in the reduced NO bioavailability. This review summarizes the available information regarding lower NO bioavailability in these pregnancy pathologies. A common NO-dependent mechanism in PE, GDM and MSPH contributing to fetoplacental endothelial dysfunction is described.

Stanniocalcin-2 overexpression reduces atherosclerosis in hypercholesterolemic mice

Background and aimThe metalloproteinase pregnancy-associated plasma protein-A (PAPP-A) has been suggested as a proatherogenic molecule by its ability to locally increase insulin-like growth factor signaling. Stanniocalcin-2 (STC2) was recently discovered to be a potent inhibitor of PAPP-A activity, but has not previously been implicated in vascular disease. The aim of this study was to substantiate the interaction between PAPP-A and STC2 as a potential local regulatory mechanism in the artery wall. Methods and resultsWe found that PAPP-A is secreted from cultured primary smooth muscle cells obtained from human aortas as a covalent complex with STC2, devoid of proteolytic activity. Extracts of human carotid atherosclerotic plaques contain both complexed and uncomplexed PAPP-A, and we show by immunohistochemistry that PAPP-A and STC2 are present in the tissue throughout early human lesion development. We then used adeno-associated virus-mediated expression of STC2 to increase the fraction of PAPP-A present in the inhibited state and found that it decreased the development of atherosclerosis by 47% (P = 0.0005) in apolipoprotein E-deficient mice challenged with a Western type diet compared to controls. ConclusionsThis study is the first to suggest the involvement of STC2 in regulating PAPP-A activity during the development of atherosclerosis. Furthermore, we demonstrate that lesion development can be inhibited in an experimental model by driving the balance towards inhibited PAPP-A.

Impaired Development of Early Endometriotic Lesions in CD44 Knockout Mice.

Previous studies have shown endometrial cell (EC) CD44 and peritoneal mesothelial cell (PMC)-associated hyaluronan (hyaluronic acid [HA]) are involved in the attachment of endometrial stroma and epithelial cells to peritoneal mesothelium. Here we assess the CD44-HA interaction in the formation of the early endometriotic lesion using CD44(-/-) (knockout) mice. Using an established murine model and crossover technique, endometrial tissue from donor mice (wild type [WT] and CD44(-/-)) was used to induce endometriosis in recipient mice (WT and CD44(-/-)). Endometriotic lesions were visualized by fluorescent microscopy and confirmed by hematoxylin and eosin staining. Early endometriotic lesions were decreased when CD44(-/-) endometrium was placed in WT recipients and when WT endometrium was placed in CD44(-/-) recipients (P = .002). Early endometriotic lesions were also significantly decreased when both peritoneal and endometrial tissues lacked CD44 expression (P < .01). These studies demonstrate that both EC and PMC CD44 play a role in the development of early endometriotic lesion.

"Microglial nodules" and "newly forming lesions" may be a Janus face of early MS lesions; implications from virus-induced demyelination, the Inside-Out model.

BackgroundAlthough the precise mechanism of initial lesion development in multiple sclerosis (MS) remains unclear, two different neuropathological findings have been reported as a potential early pathology of MS: “microglial nodules” and “newly forming lesions”, both of which contain neither T cell infiltration nor demyelination. In microglial nodules, damaged axons were associated with a small number of aggregated macrophages/microglia, while oligodendrocyte apoptosis was a characteristic in newly forming lesions. However, is the presence of “microglial nodules” and “oligodendrogliopathy” mutually exclusive? Might these two different observations be the same neuropathology (as proposed by the concept, “preactive lesions”), but interpreted differently based on the different theories of early MS lesion development, using different staining methods?DiscussionSince two studies are looking at two distinct aspects of early MS pathogenesis (one focused on axons and the other on oligodendrocytes), in a sense, one can say that these two studies are complementary. On the other hand, experimentally, Wallerian degeneration (WD) has been demonstrated to induce both microglial nodules and oligodendrocyte apoptosis in the central nervous system (CNS). Here, when encephalitogenic T cells are present in the periphery in both autoimmune and viral models of MS, induction of WD in the CNS has been shown to result in the recruitment of T cells along the degenerated tract, leading to demyelination (Inside-Out model). These experimental findings are consistent with early MS pathology described by both “microglial nodules” and “newly forming lesions”.ConclusionsThe differences between the two neuropathological findings may be based on the preference of staining methods, where one group observed axonal and microglial pathology and the other observed oligodendrocyte apoptosis; a Janus face that is looked at from the two different sides.

Dabigatran etexilate retards the initiation and progression of atherosclerotic lesions and inhibits the expression of oncostatin M in apolipoprotein E-deficient mice.

ObjectiveThrombin has multiple proatherogenic effects including platelet activation and the induction of inflammatory processes. Recently, the cytokine oncostatin M has been shown to have proinflammatory effects. This study was designed to investigate the effects of thrombin inhibition on the initiation and progression of atherosclerosis and on the expression of oncostatin M.MethodsApolipoprotein E-deficient mice at different ages were fed the thrombin inhibitor dabigatran etexilate. The mean lesion area was measured in the aortic sinus and in the innominate artery. CD45-positive cells within the aortic tissue were measured by flow cytometry. Oncostatin M expression was measured in the tissue sections by immunocytochemistry.ResultsTreatment with dabigatran etexilate resulted in a significant reduction of the mean area of atherosclerotic lesions in the aortic sinus in both the young mice (11,176±1,500 μm2 (control) versus 3,822±836 μm2 (dabigatran etexilate), P<0.05) and selectively in the older mice at 28 weeks (234,099±13,500 μm2 (control) versus 175,226±16,132 μm2 (dabigatran etexilate), P<0.05). There were also fewer CD45-positive cells within the aortas of the dabigatran-treated mice and enhanced NO production in endothelial cells pretreated with dabigatran. In addition, the expression of oncostatin M was reduced in the lesions of dabigatran etexilate-treated mice.ConclusionInhibition of thrombin by dabigatran retards the development of early lesions and the progression of some established lesions in ApoE–/– mice. It improves endothelial function and retards macrophage accumulation within the vascular wall. Dabigatran also inhibits the expression of oncostatin M, and this suggests that oncostatin M may play a role in the initiation and progression of atherosclerosis.

Enhancing our understanding of white matter changes in early multiple sclerosis.

This scientific commentary refers to ‘Permeability of the blood–brain barrier predicts conversion from optic neuritis to multiple sclerosis’, by Cramer et al. (doi:10.1093/brain/awv203). The cause of multiple sclerosis remains one of the great mysteries of neurology. Despite its clinico-neuropathological characterization almost 150 years ago by Charcot, we continue to gain fundamental knowledge about multiple sclerosis pathology. A major roadblock to the better understanding of multiple sclerosis, and many chronic CNS diseases, is the lack of adequate longitudinal histological analyses of the CNS. These are needed to show the early development of individual lesions as well as the changes in neuropathology over the years. How do multiple sclerosis lesions begin? Neuroimaging has provided clues by revealing that lesions commence with blood–brain barrier (BBB) breakdown as indicated by gadolinium enhancement. In the BECOME study in which monthly gadolinium-enhanced brain MRIs were performed in 75 subjects with multiple sclerosis for 2 years, more than 95% of new lesions seen on T2-weighted/FLAIR magnetic resonance began with gadolinium enhancement (Cadavid et al. , 2009). However, we do not know what precedes BBB breakdown. It is likely that subtle focal or global changes occur prior to gadolinium enhancement within the normal-appearing CNS. To understand early events in lesion development, investigators often focus on patients who are at the early stages of a single demyelinating event, so-called ‘clinically isolated syndrome’ (CIS). In this issue of Brain , Cramer and co-workers examine patients with CIS limited to the optic nerves to determine whether subtle changes in BBB permeability are also present …

Retinylamine Benefits Early Diabetic Retinopathy in Mice

Recent evidence suggests an important role for outer retinal cells in the pathogenesis of diabetic retinopathy (DR). Here we investigated the effect of the visual cycle inhibitor retinylamine (Ret-NH2) on the development of early DR lesions. Wild-type (WT) C57BL/6J mice (male, 2 months old when diabetes was induced) were made diabetic with streptozotocin, and some were given Ret-NH2 once per week. Lecithin-retinol acyltransferase (LRAT)-deficient mice and P23H mutant mice were similarly studied. Mice were euthanized after 2 (WT and Lrat(-/-)) and 8 months (WT) of study to assess vascular histopathology, accumulation of albumin, visual function, and biochemical and physiological abnormalities in the retina. Non-retinal effects of Ret-NH2 were examined in leukocytes treated in vivo. Superoxide generation and expression of inflammatory proteins were significantly increased in retinas of mice diabetic for 2 or 8 months, and the number of degenerate retinal capillaries and accumulation of albumin in neural retina were significantly increased in mice diabetic for 8 months compared with nondiabetic controls. Administration of Ret-NH2 once per week inhibited capillary degeneration and accumulation of albumin in the neural retina, significantly reducing diabetes-induced retinal superoxide and expression of inflammatory proteins. Superoxide generation also was suppressed in Lrat(-/-) diabetic mice. Leukocytes isolated from diabetic mice treated with Ret-NH2 caused significantly less cytotoxicity to retinal endothelial cells ex vivo than did leukocytes from control diabetics. Administration of Ret-NH2 once per week significantly inhibited the pathogenesis of lesions characteristic of early DR in diabetic mice. The visual cycle constitutes a novel target for inhibition of DR.

Serum Amyloid A Facilitates Early Lesion Development in Ldlr-/- Mice.

BackgroundAtherosclerosis is a chronic inflammatory disorder, and several studies have demonstrated a positive association between plasma serum amyloid A (SAA) levels and cardiovascular disease risk. The aim of the study was to examine whether SAA has a role in atherogenesis, the underlying basis of most cardiovascular disease.Methods and ResultsMice globally deficient in acute-phase isoforms Saa1 and Saa2 (Saa−/−) were crossed to Ldlr−/− mice (Saa−/−Ldlr−/−). Saa−/−Ldlr−/− mice demonstrated a 31% reduction in lesional area in the ascending aorta but not in the aortic root or innominate artery after consuming a high-fat, high-cholesterol Western-type diet for 6 weeks. The lesions were predominantly macrophage foam cells. The phenotype was lost in more mature lesions in mice fed a Western-type diet for 12 weeks, suggesting that SAA is involved in early lesion development. The decreased atherosclerosis in the Saa−/−Ldlr−/− mice occurred despite increased levels of blood monocytes and was independent of plasma lipid levels. SAA is produced predominantly by hepatocytes and macrophages. To determine which source of SAA may have a dominant role in lesion development, bone marrow transplantation was performed. Ldlr−/− mice that received bone marrow from Saa−/−Ldlr−/− mice had slightly reduced ascending aorta atherosclerosis compared with Saa−/−Ldlr−/− mice receiving bone marrow from Ldlr−/− mice, indicating that the expression of SAA by macrophages may have an important influence on atherogenesis.ConclusionsThe results indicate that SAA produced by macrophages promotes early lesion formation in the ascending aorta.

Abstract B16: Contributions of Ras and EZH2 in acinar to ductal metaplasia and ductal carcinoma in transgenic mouse pancreas

Abstract Activating mutations of the ras protooncogene is the most frequent and an early genetic alteration associated with pancreatic cancer. To examine the link between mutant ras oncogenes and exocrine pancreatic cancer, and to develop mouse models of PanINs and also of lesions that progress to malignancy, we generated transgenic mice expressing either Kras or Hras in pancreas. The tetracycline transactivator system expression was targeted to the pancreatic acinar cells via the elastase promoter element. The transactivation target ras genes were placed under the control of the tetracycline-response element. Most double transgenic founder mice displayed perinatal pancreatic acinar cell hyperplasia and dysplasia. However, only adult mice expressing Hras displayed preinvasive pancreatic neoplastic lesions with ductal morphology. Therefore, these Kras and Hras models each represent useful models in which either the lesion histotype and agressiveness (Hras) or the initiating genetic alteration overlap with the human disease (Kras). More recently, we have developed and are characterizing the contributions of expressing enhancer of zeste 2 homolog (EZH2), a histone methyl transferase and key regulator of cell differentiation and tissue regeneration, in modifying aggressiveness of mutated ras genes in vivo. Our findings suggest that ras mutations are associated with development of early stage duct-like lesions in pancreas, which vary in severity depending on the mutated ras gene expressed and the stage of development and growth of pancreas tissue. Citation Format: Jayne Ellis, Eric P. Sandgren, Paul J. Grippo, Marxa L. Figueiredo. Contributions of Ras and EZH2 in acinar to ductal metaplasia and ductal carcinoma in transgenic mouse pancreas. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Innovations in Research and Treatment; May 18-21, 2014; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2015;75(13 Suppl):Abstract nr B16.

The Antiatherogenic Effect of Fish Oil in Male Mice Is Associated with a Diminished Release of Endothelial ADAM17 and ADAM10 Substrates1–3

Background: Growing evidence suggests that disintegrin and metalloprotease (ADAM) 17 (ADAM17) and ADAM10 contribute to the pathogenesis of vascular diseases. ADAM17 promotes inflammatory processes by liberating tumor necrosis factor α, interleukin 6 receptor (IL-6R), and tumor necrosis factor receptor 1 (TNFR1). ADAM17 and ADAM10 modulate vascular permeability by cleaving endothelial adhesion molecules such as junctional adhesion molecule A (JAM-A) and vascular endothelial cadherin (VE-cadherin), respectively.Objective: This study was designed to investigate whether a link might exist between the protective effects of fish oil (FO) supplementation against atherosclerosis and ADAM functionMethods: Male LDL receptor knockout (LDLR−/−) mice and male wild-type (WT) mice were fed a Western diet (200 g/kg fat, 1.5 g/kg cholesterol) containing either 20% lard (LDLR−/−-lard and WT-lard groups) or 10% lard combined with 10% FO (LDLR−/−-FO and WT-FO groups) for 12 wk. Atherosclerotic lesion development and fatty acid composition of liver microsomes were evaluated. ADAM10 and ADAM17 expression was determined by quantitative real-time polymerase chain reaction and immunoblot analyses. Concentrations of soluble ADAM substrates in plasma and liver extracts were measured by ELISAResults: Diets supplemented with FO markedly reduced development of early atherosclerotic lesions in LDLR−/− mice (LDLR−/−-lard group vs. LDLR−/−-FO group mean ± SD: 29.6 ± 6.1% vs. 22.5 ± 4.2%, P < 0.05). This was not accompanied by changes in expression of ADAM17 or ADAM10 in the aorta or liver. No dietary effects on circulating TNFR1 (LDLR−/−-lard group vs. LDLR−/−-FO group mean ± SD: 1.22 ± 0.23 vs. 1.39 ± 0.28, P > 0.2) or IL-6R (1.06 ± 0.12 vs. 0.98 ± 0.09 fold of WT-lard group, P > 0.1), classical substrates of ADAM17 on macrophages, and neutrophil granulocytes were observed. However, a reduction in atherosclerotic lesions in the LDLR−/−-FO group was accompanied by a significant reduction in the circulating endothelial cell adhesion molecules JAM-A (LDLR−/−-lard group vs. LDLR−/−-FO group mean ± SD: 1.42 ± 0.20 vs. 0.95 ± 0.56 fold of WT-lard group, P < 0.05), intercellular adhesion molecule 1 (1.15 ± 0.14 vs. 0.88 ± 0.17 fold of WT-lard group, P < 0.05), and VE-cadherin (0.88 ± 0.12 vs. 0.72 ± 0.15 fold of WT-lard group, P < 0.05), reflecting reduced ADAM activity in endothelial cellsConclusion: FO exerted an antiatherogenic effect on male LDLR−/− mice that was accompanied by a reduced release of ADAM17 and ADAM10 substrates from endothelial cells. It is suggested that FO-decreased ADAM activity contributes to improved endothelial barrier function and thus counteracts intimal lipoprotein insudation and macrophage accumulation.

How do K-RAS-activated cells evade cellular defense mechanisms?

Lung adenocarcinomas, like other cancers, develop through the accumulation of epigenetic and genetic alterations. Numerous studies have shown that K-RAS mutation is among the most important early events in carcinogenesis of the lung. However, it is also well established that growth-stimulating signals feed back into growth-suppressing pathways, and any imbalance in these signaling networks will cause the cell to exit the cell cycle, thereby preventing uncontrolled cell growth. How, then, do K-RAS-activated cells evade cellular defense mechanisms? To answer this question, it is necessary to identify the molecular event(s) responsible for the development of early dysplastic lesions that are unable to defend against aberrant oncogene activation. Lineage-determining transcriptional regulators govern differentiation status during normal lung development, as well as in lung adenocarcinoma. Among the genes involved in K-RAS-induced lung tumorigenesis, RUNX3 is unique: inactivation of Runx3 in mouse lung induces lung adenoma and abrogates the ARF–p53 pathway. This observation raises the possibility of intimate cross-talk between the differentiation program and oncogene surveillance. In this review, we summarized evidences suggesting that K-RAS-activated cells do not evade cellular defense mechanisms per se; instead, cells with K-RAS mutations are selected only if they occur in cells in which defense mechanism is abrogated.

Modulation of platelet and monocyte function by the chemokine fractalkine (CX3 CL1) in cardiovascular disease.

The chemokine fractalkine, CX3CL1, bears unique features within the chemokine family: it exists in a membrane bound form acting as an adhesion molecule and surface receptor; however, when cleaved by ADAM 10, it functions as a soluble chemokine. Fractalkine and its chemokine receptor CX3CR1 are known to have multiple roles in diverse human diseases, for example inflammatory diseases, rheumatoid arthritis, renal diseases and atherosclerosis. This review is based on the material obtained via PubMed up to November 2014. The key search terms used were 'fractalkine', 'CX3CL1', 'CX3CR1', 'cardiovascular disease', 'platelets', 'monocytes' and 'platelet-monocyte complexes'. Atherosclerosis is recognized as a highly inflammatory disease, and it has become increasingly evident that the immune system plays an important role in atherogenesis and atheroprogression. Two blood cell populations are crucially involved in the early development of atherosclerotic lesions: monocytes and platelets. They are detected at vascular sites of endothelial dysfunction and are involved in inflammatory immune responses. These cells directly interact with each other, forming platelet-monocyte complexes that are increased in cardiovascular diseases. During the development of atherosclerosis, fractalkine mediates leukocyte recruitment to the inflamed endothelium, which promotes early formation of lesions. This process only effectively works in the presence of activated platelets. It has been suggested that fractalkine and its receptor contribute to platelet-monocyte aggregate formation underlining the two important impacts of this chemokine for platelets as well as monocytes. Interesting data hint at a role of fractalkine for platelet activation, adhesion and subsequent monocyte recruitment to activated endothelial cells in cardiovascular diseases. However, the exact mechanisms remain to become unravelled.