Pancreatic acinar cells possess very high protein synthetic rates as they need to produce and secrete large amounts of digestive enzymes. Acinar cell damage and dysfunction cause malnutrition and ...pancreatitis, and inflammation of the exocrine pancreas that promotes development of pancreatic ductal adenocarcinoma (PDAC), a deadly pancreatic neoplasm. The cellular and molecular mechanisms that maintain acinar cell function and whose dysregulation can lead to tissue damage and chronic pancreatitis are poorly understood. It was suggested that autophagy, the principal cellular degradative pathway, is impaired in pancreatitis, but it is unknown whether impaired autophagy is a cause or a consequence of pancreatitis. To address this question, we generatedAtg7Δpan
mice that lack the essential autophagy-related protein 7 (ATG7) in pancreatic epithelial cells.Atg7Δpan
mice exhibit severe acinar cell degeneration, leading to pancreatic inflammation and extensive fibrosis. Whereas ATG7 loss leads to the expected decrease in autophagic flux, it also results in endoplasmic reticulum (ER) stress, accumulation of dysfunctional mitochondria, oxidative stress, activation of AMPK, and a marked decrease in protein synthetic capacity that is accompanied by loss of rough ER.Atg7Δpan
mice also exhibit spontaneous activation of regenerative mechanisms that initiate acinar-to-ductal metaplasia (ADM), a process that replaces damaged acinar cells with duct-like structures.
Despite expression of oncogenic KRAS, premalignant pancreatic intraepithelial neoplasia 1 (PanIN1) lesions rarely become fully malignant pancreatic ductal adenocarcinoma (PDAC). The molecular ...mechanisms through which established risk factors, such as chronic pancreatitis, acinar cell damage, and/or defective autophagy increase the likelihood of PDAC development are poorly understood. We show that accumulation of the autophagy substrate p62/SQSTM1 in stressed KrasG12D acinar cells is associated with PDAC development and maintenance of malignancy in human cells and mice. p62 accumulation promotes neoplastic progression by controlling the NRF2-mediated induction of MDM2, which acts through p53-dependent and -independent mechanisms to abrogate checkpoints that prevent conversion of differentiated acinar cells to proliferative ductal progenitors. MDM2 targeting may be useful for preventing PDAC development in high-risk individuals.
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•IKKα-deficiency-induced p62 accumulation drives PDAC progression•MDM2 links the autophagy substrate p62 to neoplastic progression in the pancreas•A p62-NRF2-MDM2 module acts via p53-dependent and -independent mechanisms•A p62-NRF2-MDM2 module converts acinar cells into progenitor-like cells
Todoric et al. demonstrate that pancreatitis-induced accumulation of the autophagy substrate p62/SQSTM1 in the context of oncogenic KRAS promotes progression to pancreatic ductal adenocarcinoma. This p62 function relies on NRF2-driven induction of MDM2 and both p53 dependent and independent activity of MDM2.
Androgens have important cardiometabolic actions in males, but their metabolic role in females is unclear. To determine the physiologic androgen receptor (AR)‐dependent actions of androgens on ...atherogenesis in female mice, we generated female AR‐knockout (ARKO) mice on an atherosclerosis‐prone apolipoprotein E (apoE)‐deficient background. After 8 weeks on a high‐fat diet, but not on a normal chow diet, atherosclerosis in aorta was increased in ARKO females (+59% vs. control apoE‐deficient mice with intact AR gene). They also displayed increased body weight (+18%), body fat percentage (+62%), and hepatic triglyceride levels, reduced insulin sensitivity, and a marked atherogenic dyslipidemia (serum cholesterol, +52%). Differences in atherosclerosis, body weight, and lipid levels between ARKO and control mice were abolished in mice that were ovariectomized before puberty, consistent with a protective action of ovarian androgens mediated via the AR. Furthermore, the AR agonist dihydrotestosterone reduced atherosclerosis (‐41%; thoracic aorta), subcutaneous fat mass (‐44%), and cholesterol levels (‐35%) in ovariectomized mice, reduced hepatocyte lipid accumulation in hepatoma cells in vitro, and regulated mRNA expression of hepatic genes pivotal for lipid homeostasis. In conclusion, we demonstrate that the AR protects against diet‐induced atherosclerosis in female mice and propose that this is mediated by modulation of body composition and lipid metabolism.—Fagman, J. B., Wilhelmson, A. S., Motta, B. M., Pirazzi, C., Alexanderson, C., De Gendt, K., Verhoeven, G., Holmäng, A., Anesten, F., Jansson, J.‐O., Levin, M., Borén, J., Ohlsson, C., Krettek, A., Romeo, S., Tivesten, A. The androgen receptor confers protection against diet‐induced atherosclerosis, obesity, and dyslipidemia in female mice. FASEB J. 29, 1540‐1550 (2015). www.fasebj.org
Testosterone deficiency in men is associated with increased risk for autoimmunity and increased B cell numbers through unknown mechanisms. Here we show that testosterone regulates the cytokine BAFF, ...an essential survival factor for B cells. Male mice lacking the androgen receptor have increased splenic B cell numbers, serum BAFF levels and splenic Baff mRNA. Testosterone deficiency by castration causes expansion of BAFF-producing fibroblastic reticular cells (FRCs) in spleen, which may be coupled to lower splenic noradrenaline levels in castrated males, as an α-adrenergic agonist decreases splenic FRC number in vitro. Antibody-mediated blockade of the BAFF receptor or treatment with the neurotoxin 6-hydroxydopamine revert the increased splenic B cell numbers induced by castration. Among healthy men, serum BAFF levels are higher in men with low testosterone. Our study uncovers a previously unrecognized regulation of BAFF by testosterone and raises important questions about BAFF in testosterone-mediated protection against autoimmunity.
2-Methoxyestradiol (2ME2), a metabolite of 17β-estradiol (E2), exerts bone sparing effects in animal models. We hypothesized that the underlying mechanism is back conversion of 2ME2 to E2, which ...subsequently acts via estrogen receptor (ER)α. We measured serum E2 levels in orchidectomized wild-type (WT) mice treated with 2ME2 66.6 μg/d or placebo. In placebo-treated animals, E2 was below the detection limit. In 2ME2-treated mice, the serum E2 level was 4.97 ± 0.68 pg/mL. This corresponds to the level found in diesterus in cycling female mice. Next, we investigated bone parameters in orchidectomized WT and ERα knockout mice treated with 2ME2 or placebo for 35 days. 2ME2 (6.66 μg/d) preserved trabecular and cortical bone in WT mice. Trabecular volumetric-bone mineral density was 64 ± 20%, and trabecular bone volume/total volume was 60 ± 20% higher in the metaphyseal region of the femur in the 2ME2 group, compared with placebo (P < .01). Both trabecular number and trabecular thickness were increased (P < .01). Cortical bone mineral content in the diaphyseal region of the femur was 31 ± 3% higher in the 2ME2 group, compared with placebo (P < .001). This was due to larger cortical area (P < .001). Three-point bending showed an increased bone strength in WT 2ME2-treated animals compared with placebo (maximum load Fmax +19±5% in the 2ME2 group, P < .05). Importantly, no bone parameter was affected by 2ME2 treatment in ERα knockout mice. In conclusion, 2ME2 treatment of orchidectomized mice results in increased serum E2. ERα mediates the bone sparing effects of 2ME2. The likely mediator of this effect is E2 resulting from back conversion of 2ME2.
Intimal hyperplasia is a vascular pathological process involved in the pathogenesis of atherosclerosis. Data suggest that T, the most important sex steroid hormone in males, protects men from ...atherosclerotic cardiovascular disease. T mainly acts via the androgen receptor (AR), and in this study we evaluated formation of intimal hyperplasia in male AR knockout (ARKO) mice using a vascular injury model. Two weeks after ligation of the carotid artery, male ARKO mice showed increased intimal area and intimal thickness compared with controls. After endothelial denudation by an in vivo scraping injury, there was no difference in the reendothelialization in ARKO compared with control mice. Ex vivo, we observed increased outgrowth of vascular smooth muscle cells from ARKO compared with control aortic tissue explants; the number of outgrown cells was almost doubled in ARKO. In vitro, stimulation of human aortic vascular smooth muscle cells with a physiological T concentration inhibited both migration and proliferation of the cells. Analyzing the expression of central regulators of cell proliferation and migration, we found that mRNA and protein levels of p27 were lower in uninjured arteries from ARKO mice and that T replacement to castrated male mice increased p27 mRNA in an AR-dependent manner. In conclusion, AR deficiency in male mice increases intimal hyperplasia in response to vascular injury, potentially related to the effects of androgens/AR to inhibit proliferation and migration of smooth muscle cells.
Nf1 mutations or deletions are suggested to underlie the tumor predisposition of NF1 (neurofibromatosis type 1) and few treatments are available for treating NF1 patients with advanced malignant ...tumors. Aberrant activation of Ras in Nf1-deficient conditions is responsible for the promotion of tumorigenesis in NF1. PKC is proven to be an important factor in supporting the viability of Nf1-defected cells, but the molecular mechanisms are not fully understood. In this study, we demonstrate that the inhibition of protein kinase C (PKC) by 1-O-Hexadecyl-2-O-methyl-rac-glycerol (HMG, a PKC inhibitor) preferentially sensitizes Nf1-defected cells to apoptosis, via triggering a persistent mitotic arrest. In this process, Ral A is activated. Subsequently, Chk1 is phosphorylated and translocated to the nucleus. Silencing Ral A significantly blocks Chk1 nuclear translocation and releases HMG-treated Nf1-deficient cells from mitotic arrest, resulting in the reduction of the magnitude of apoptosis. Thus, our study reveals that PKC is able to maintain the homeostasis or viability of Nf1-defected cells and may serve as a potential target for developing new therapeutic strategies.
2-Methoxyestradiol (2ME2), a metabolite of 17beta-estradiol (E2), exerts bone sparing effects in animal models. We hypothesized that the underlying mechanism is back conversion of 2ME2 to E2, which ...subsequently acts via estrogen receptor (ER)alpha. We measured serum E2 levels in orchidectomized wild-type (WT) mice treated with 2ME2 66.6 mug/d or placebo. In placebo-treated animals, E2 was below the detection limit. In 2ME2-treated mice, the serum E2 level was 4.97 + or - 0.68 pg/mL. This corresponds to the level found in diesterus in cycling female mice. Next, we investigated bone parameters in orchidectomized WT and ERalpha knockout mice treated with 2ME2 or placebo for 35 days. 2ME2 (6.66 mug/d) preserved trabecular and cortical bone in WT mice. Trabecular volumetric-bone mineral density was 64 + or - 20%, and trabecular bone volume/total volume was 60 + or - 20% higher in the metaphyseal region of the femur in the 2ME2 group, compared with placebo (P< .01). Both trabecular number and trabecular thickness were increased (P< .01). Cortical bone mineral content in the diaphyseal region of the femur was 31 + or - 3% higher in the 2ME2 group, compared with placebo (P< .001). This was due to larger cortical area (P< .001). Three-point bending showed an increased bone strength in WT 2ME2-treated animals compared with placebo (maximum load Fmax +19+ or -5% in the 2ME2 group, P< .05). Importantly, no bone parameter was affected by 2ME2 treatment in ERalpha knockout mice. In conclusion, 2ME2 treatment of orchidectomized mice results in increased serum E2. ERalpha mediates the bone sparing effects of 2ME2. The likely mediator of this effect is E2 resulting from back conversion of 2ME2.
Background
Postpancreatectomy hemorrhage grade C (PPH C) is a dreaded complication after pancreaticoduodenectomy (PD) with high mortality rate. Concurrent risk factors for PPH C have been difficult ...to recognize. Connection between postoperative pancreatic fistulas (POPF) and PPH C is well known, but POPF is often unknown prior to the PPH. The aim of this retrospective study was to define potential predictive factors for PPH C.
Methods
Retrospectively, 517 patients who underwent PD between 2003 and 2018 were included in the study. Twenty-three patients with PPH C were identified, and a matched control group of 92 patients was randomly selected. Preoperative data (body mass index, cardiovascular disease, history of abdominal surgery, biliary stent, C-reactive protein (CRP), ASA-score), perioperative data (bleeding, pancreatic anastomosis, operation time), and postoperative data (CRP, drain amylase, POPF, biliary fistula) were analyzed as potential predictors of PPH C.
Results
High postoperative CRP (median 140 mg/L on day 5 or 6) correlated with the development of PPH C (
p
< 0.05). Postoperative drain amylase levels were not clinically relevant for occurrence of PPH C. Grade C POPF or biliary leak was observed in the majority of the PPH C patients, but the leaking anastomoses were not detected before the bleeding started.
Discussion
High postoperative CRP levels are related to an increased risk of PPH C.
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