-
Daniel J. Klionsky,
Fabio C. Abdalla,
Hagai Abeliovich,
Robert T. Abraham,
Abraham Acevedo-Arozena,
Khosrow Adeli,
Lotta Agholme,
Maria Agnello,
Patrizia Agostinis,
Julio A. Aguirre-Ghiso, [......],
Gabriella Marfe,
Guillermo Mariño,
Maria Markaki,
Mark R. Marten,
Seamus J. Martin,
Camille Martinand-Mari,
Wim Martinet,
Marta Martinez-Vicente,
Matilde Masini,
Paolo Matarrese
[show abstract]
[hide abstract]
ABSTRACT: In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process versus those that measure flux through the autophagy pathway (i.e., the complete process);5,6 thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
Autophagy 04/2012; 8(4). · 7.45 Impact Factor
-
Daniel J Klionsky,
Fabio C Abdalla,
Hagai Abeliovich,
Robert T Abraham,
Abraham Acevedo-Arozena,
Khosrow Adeli,
Lotta Agholme,
Maria Agnello,
Patrizia Agostinis,
Julio A Aguirre-Ghiso, [......],
Changlian Zhu,
Wei-Guo Zhu,
Xiao-Feng Zhu,
Xiongwei Zhu,
Yuangang Zhu,
Teresa Zoladek,
Wei-Xing Zong,
Antonio Zorzano,
Jürgen Zschocke,
Brian Zuckerbraun
[show abstract]
[hide abstract]
ABSTRACT: In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
Autophagy 04/2012; 8(4):445-544. · 7.45 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The broccoli isothiocyanate, sulforaphane (SFN), was recently identified as being capable of eliminating highly therapy-resistant pancreatic carcinoma (PC) cells without inducing toxic side effects. While SFN has been shown to stimulate autophagy or 'self-eating', it is unclear whether this catabolic process is a pro- or anti-tumorigenic response. To investigate the role of autophagy in SFN-induced cell death, established PC cell lines were treated with SFN, and the induction of autophagy was evaluated by detecting the abundance of autophagic vesicles by electron microscopy, the increase in converted LC3-II by Western blot analysis and the autophagosome puncta of GFP-LC3 by immunofluorescence. SFN-induced autophagy was suppressed by the autophagy inhibitor chloroquine, while the autophagy inducer rapamycin did not further enhance autophagy in PC cells. Importantly, neither modulator altered SFN cytotoxicity, suggesting that SFN-induced autophagy and cell death act independently of each other. In contrast, the antioxidant N-acetyl-cysteine sustained cell viability and prevented autophagy induction after SFN exposure, indicating that both signaling pathways depend on reactive oxygen species (ROS). Our studies provide a valuable new mechanistic insight into the SFN-induced elimination of PC cells and suggest that an SFN-enriched diet potentially enhances ROS-releasing chemotherapeutic agents.
International Journal of Oncology 07/2011; 39(1):101-9. · 2.40 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Systemic complications in alcoholic pancreatitis are supposed to be aggravated by inflammatory liver damage. Resident macrophages including hepatic Kupffer cells play a pivotal role in mediating systemic complications in severe necrotizing pancreatitis (SNP). The aim of this study was to evaluate the effects of Kupffer cell inhibition on the inflammatory liver damage in experimental alcoholic pancreatitis.
Rats were fed with either alcohol or control diet for 6 weeks before induction of SNP. Animals were allocated into 4 groups: healthy controls, controls with SNP, SNP with gadolinium chloride or glycine (permanent vs temporary inhibition of hepatic Kupffer cells) prophylaxis. Hepatic microcirculation and morphologic damage of the liver and pancreas were assessed.
Alcohol feeding and SNP increased hepatic and pancreatic injury compared with SNP alone. Gadolinium chloride and glycine improved hepatic microcirculation. In contrast, pancreatic and hepatic morphological damage was reduced by gadolinium chloride but not by glycine.
Alcohol exposure aggravates hepatic and pancreatic injury in SNP. Gadolinium chloride reduces both microcirculatory and morphological damage, whereas glycine did not improve histological damage.
Pancreas 11/2009; 39(4):502-9. · 2.39 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In contrast to apoptosis, necrosis is generally viewed as a pro-inflammatory cell death mechanism. Accumulation of autophagosomes and massive acinar cell necrosis is observed in human acute pancreatitis, a severe and potentially lethal inflammatory condition. We have investigated the incidence of apoptosis, autophagy and necrosis affecting acinar cells in a rat model of acute pancreatitis induced by chronic alcohol intake and acute endotoxemia. We have observed that the combination of alcohol exposure and endotoxemia results in substantial accumulation of autophagosomes without an increase in autolysosomes, coupled to the depletion of LAMP-2, a lysosomal protein required for the proper fusion of autophagosomes with lysosomes. Alcohol plus endotoxemia favors the switch from apoptotic to necrotic cell death, as indicated by histopathological examination, reduced ATP levels, suppressed caspase activation, as well as the nuclear release of the proinflammatory factor HMGB1. Importantly, patients with alcoholic pancreatitis also exhibit local LAMP-2 depletion, recapitulating the results obtained in the animal model. We suggest that acinar cell vacuolization in pancreatitis is mediated by an endotoxemia-induced depletion of LAMP-2, which in turn facilitates the accumulation of autophagosomes due to the deficient formation of autolysosomes. Hence, we postulate that the depletion of lysosomal proteins may play a critical role in the pathogenesis of acute pancreatitis.
Autophagy 09/2009; 5(6):850-3. · 7.45 Impact Factor
-
Lutz Schneider,
Werner Hartwig,
Thomas Flemming,
Thilo Hackert, Franco Fortunato,
Matthias Heck,
Martha-Maria Gebhard,
Peter P Nawroth,
Angelika Bierhaus,
Markus W Buchler,
Jens Werner
[show abstract]
[hide abstract]
ABSTRACT: Microcirculatory disturbances are known to play a pivotal role in the pathogenesis of severe necrotizing pancreatitis (SNP). Calcitonin gene-related peptide (CGRP) is a vasodilatatory neuropeptide with potential anti-inflammatory effects. This study characterizes the protective effects and the anti-inflammatory pathway of exogenous CGRP in SNP.
SNP was induced in rats using the glycodeoxycholic acid model. CGRP was injected prophylactically before or therapeutically after initiation of the disease. Pancreatic damage was assessed using intravital microscopy, histology, NF-kappaB p50/p65 electrophoretic mobility shift assay, serum cytokine assay and ICAM-1 immunohistochemistry at 6 or 12 h after the onset of disease.
Pancreatic microcirculatory disturbances, nuclear NF-kappaB levels and pancreatic ICAM-1 expression were increased in SNP compared to controls. After CGRP application, microcirculatory disturbances, NF-kappaB levels and pancreatic ICAM-1 expression were attenuated compared to pancreatitis alone. Moreover, pancreatic morphologic damage was significantly reduced by both prophylactic and therapeutic application of CGRP.
CGRP is a neuropeptide that ameliorates the development of SNP in rats and may provide new treatment options. Its anti-inflammatory effects appear to be mediated by the modulation of pancreatic microcirculation and the inflammatory cascade.
Pancreatology 09/2009; 9(5):662-9. · 1.99 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Acute pancreatitis constitutes a life-threatening condition in which pancreatic acinar cells undergo massive cell death. We investigated the incidence of apoptosis, autophagy, and necrosis affecting acinar cells in the early onset of acute pancreatitis induced by chronic alcohol feeding and acute endotoxemia.
Rats were fed either an ethanol-containing or a control diet over 14 weeks and killed 3 or 24 hours after a single lipopolysaccharide injection. Apoptosis, necrosis, and autophagy of pancreatic acinar cells were assessed by histology, electron microscopy, immunofluorescence, and biochemical methods.
The combination of alcohol exposure and endotoxemia resulted in the depletion of several lysosomal proteins including lysosomal-associated membrane protein-2 (Lamp-2), a protein that is required for the proper fusion of autophagosomes with lysosomes. Accordingly, Lamp-2 depletion correlated with the accumulation of autophagosomes and a relative paucity of autolysosomes, reduced adenosine-5'-triphosphate levels, and a switch from apoptotic to necrotic cell death. This switch to necrosis was accompanied by reduced caspase activation and the nuclear release of the proinflammatory factor high mobility group box 1. Importantly, human patients with alcoholic pancreatitis also exhibited local Lamp-2 depletion, which points to a crucial role for Lamp-2 and autophagy in pancreatic acinar cell death.
Our data suggest that acinar cell vacuolization in pancreatitis is mediated by an endotoxemia-induced inhibition of the late stage of autophagy. The combination of alcohol and endotoxemia attenuated apoptosis response yet enhanced acinar cell necrosis. The depletion of lysosomal proteins plays a critical role in the early onset of acute pancreatitis.
Gastroenterology 04/2009; 137(1):350-60, 360.e1-5. · 11.68 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A noninvasive model of necrohemorrhagic pancreatitis induced by simultaneous intravenous cerulein/enterokinase (EK) infusion has recently been established in rats. The aim of the present study was to establish this new model in mice and to compare it with the rat model.
Male Balb/C mice (20 to 25 g) were used for the experiments. Pancreatitis was induced by simultaneous intravenous infusion of cerulein and EK. Controls were infused with either 0.9% NaCl, cerulein, or EK. Animals were humanely killed 6 hours after start of infusions. Pancreatic and pulmonary injury was assessed by histology, wet-to-dry weight ratio, and myeloperoxidase activity. Systemic cytokine, amylase, and lactate dehydrogenase (LDH) levels in blood were measured to assess pancreatic and systemic inflammatory response. To evaluate the role of protease activity in this model, trypsin, cathepsin B, and elastase activity were measured in pancreatic tissue. Survival experiments were performed to determine survival time and tissue injury in the later course of the disease.
Mice with simultaneous cerulein/EK infusion developed marked local and systemic organ injury compared with those animals who received cerulein or EK alone. Pancreatic and pulmonary injury increased with high concentrations of cerulein/EK infusions. Survival decreased in these animals. Whereas acinar cell apoptosis was an early finding, pancreatic necrosis was observed later in the course of the disease. Serum levels of LDH, interleukin (IL)-1 alpha, and IL-1 beta reflected cell damage and the systemic inflammatory response. Protease activity in pancreatic tissue was greatest in animals with simultaneous cerulein/EK infusion.
Using intravenous cerulein/EK infusions, a model of lethal acute pancreatitis has been established in mice. Major pancreatic edema, acinar cell apoptosis and necrosis, and pulmonary leukocyte sequestration are characteristic findings in this model. Although pancreatic injury was not as strong as in the rat model, this model may prove useful for future studies in transgenic mice.
Surgery 10/2008; 144(3):394-403. · 3.10 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Unlike edematous pancreatitis, induction of severe necrotizing pancreatitis in rats generally requires an invasive laparotomy with infusion and/or ligation of the pancreatic duct or duodenal or arterial occlusion. The aim of this study was to establish and characterize a noninvasive model of severe acute pancreatitis in rats.
Wistar rats were infused intravenously with cerulein or a combination of cerulein and enterokinase. Saline (154-mmol/L NaCl) or enterokinase only was infused in controls. In a first set of experiments, intrapancreatic protease activation and the release of cytokines were correlated with the severity of organ injury. Pancreatic and pulmonary injuries were determined at 6 h. In a second set of experiments, we assessed 24-h survival, serum parameters possibly reflecting the course of the disease, and morphologic changes later in the course of the disease.
The severity of pancreatic injury and survival were correlated strongly with the amount of enterokinase infused simultaneously with cerulein. Trypsin as well as elastase and cathepsin B activity in pancreatic tissue samples were increased markedly in these animals. Marked pancreatic hemorrhage, necrosis, and leukocyte infiltration were present in animals with the greatest amounts of enterokinase infused. IL-6 and LDH, but not IL-1beta, CRP, and amylase, in serum correlated with the severity of pancreatitis.
This noninvasive rat model of acute pancreatitis is characterized by major pancreatic necrosis, hemorrhage, and fatality. The simple and noninvasive induction technique may have advantages for future studies on inflammatory changes and sepsis in necrotizing pancreatitis compared with other currently available invasive models.
Surgery 10/2007; 142(3):327-36. · 3.10 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Regenerating protein (reg) and pancreatic stone protein (PSP) have been discovered independently in the fields of diabetes and pancreatitis.
These proteins are identical; however, because of the gap between the endocrine and exocrine field, there was never a consensus and the nomenclature has not been rectified. Since the time of the initial discovery, more isoforms have been unified. Historically, PSP was discovered long before reg, yet, in many areas outside of the pancreatitis research field, reg is being used.
For PSP/reg, a role in proliferation and regeneration of islet cells has been postulated. A hitherto insufficiently understood phenomenon is the massive up-regulation of PSP/reg in pancreatic tissue and juice under conditions of stress. Similarly, PAP (pancreatitis-associated protein)/reg III has been attributed various functional roles. Structurally, the ability to form fibrils after tryptic cleavage is a striking common features of both proteins. However, this biochemical transformation is in itself not enough to gain functional insight. Thus, physiological and genetic approaches are required to further characterize the role of these proteins in the pancreas. Recently, more evidence has been presented in support of the theory that PSP/reg plays a key role in islet neogenesis/regeneration.
In this review we discuss the debate on the localization and functional roles of PSP/reg and PAP/regIII. Therefore, we have summarized hypotheses and experimental results supporting such hypotheses.
Journal of Surgical Research 07/2006; 133(2):113-20. · 2.25 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Chronic alcohol consumption is known to increase the susceptibility to acute and chronic pancreatitis, and it is likely that a cofactor is required to initiate the progression to alcoholic pancreatitis. The severity and complications of alcoholic and nonalcoholic acute pancreatitis may be influenced by a number of cofactors, including endotoxemia. To explore the effect of a possible cofactor, we used endotoxin [lipopolysaccharide (LPS)] as a tool to induce cellular injury in the alcoholic pancreas. Single, increasing doses of endotoxin were injected in rats fed an alcohol or control diet and killed 24 h after the injection. We examined the mechanism by which LPS exacerbates pancreatic injury in alcohol-fed rats and whether the injury is associated with apoptosis or necrosis. We showed that chronic alcohol exposure alone inhibits apoptosis through the intrinsic pathway and the downstream apoptosis executor caspase-3 compared with the controls. Pancreatic necrosis and inflammation increased after LPS injection in control and alcohol-fed rats in a dose-dependent fashion but with a significantly greater response in the alcohol-fed animals. Caspase activities and TdT-mediated dUTP nick-end labeling positivity were lower in the alcoholic pancreas injected with LPS, whereas the histopathology and inflammation were more severe compared with the control-fed animals. Assessment of a putative indicator of necrosis, the ratio of ADP to ATP, indicated that alcohol exposure accelerates pancreatic necrosis in response to endotoxin. These findings suggest that the pancreas exposed to alcohol is more sensitive to LPS-induced damage because of increased sensitivity to necrotic cell death rather than apoptotic cell death. Similar to the liver, the pancreas is capable of responding to LPS with a more severe response in alcohol-fed animals, favoring pancreatic necrosis rather than apoptosis. We speculate that this mechanism may occur in acute alcoholic pancreatitis patients.
AJP Gastrointestinal and Liver Physiology 03/2006; 290(2):G232-41. · 3.43 Impact Factor
