RESUMEN
Over the past decades, studies using zebrafish have significantly advanced our understanding of the cellular basis for development and human diseases. Zebrafish have rapidly developing transparent embryos that allow comprehensive imaging of embryogenesis combined with powerful genetic approaches. However, forward genetic screens in zebrafish have generated unanticipated findings that are mirrored by human genetic studies: disruption of genes implicated in basic cellular processes, such as protein secretion or cytoskeletal dynamics, causes discrete developmental or disease phenotypes. This is surprising because many processes that were assumed to be fundamental to the function and survival of all cell types appear instead to be regulated by cell-specific mechanisms. Such discoveries are facilitated by experiments in whole animals, where zebrafish provides an ideal model for visualization and manipulation of organelles and cellular processes in a live vertebrate. Here, we review well-characterized mutants and newly developed tools that underscore this notion. We focus on the secretory pathway and microtubule-based trafficking as illustrative examples of how studying cell biology in vivo using zebrafish has broadened our understanding of the role fundamental cellular processes play in embryogenesis and disease.
Asunto(s)
Biología Celular , Desarrollo Embrionario/genética , Proteínas de Transporte Vesicular/genética , Pez Cebra/embriología , Animales , Movimiento Celular/genética , Humanos , Microtúbulos/genética , Microtúbulos/metabolismo , Fenotipo , Vertebrados/genética , Proteínas de Transporte Vesicular/metabolismo , Pez Cebra/genéticaRESUMEN
Diabetes mellitus type 2 and chronic pancreatitis are regarded as risk factors for pancreatic cancer. Pancreatic duct glands (PDGs) were recently described as a new compartment of the major duct in humans and mice. To evaluate the influence of diabetes and chronic pancreatitis on PDGs, cerulein was injected i.p., repetitively over 10 weeks, in mice exhibiting obesity and a type 2 diabetes-like syndrome (B6.V-Lep(ob/ob)) and in lean littermates. By using 5-bromo-2'-deoxyuridine (BrdU), a label-retaining cell population was characterized in PDGs. Cerulein administration led to more BrdU(+) cells in PDGs of obese mice compared with lean mice. The observed increase was specific to PDGs, because BrdU incorporation in cells of the pancreatic duct was not increased. In addition, the expression of distinct tumor markers in PDGs was characterized by Muc5ac, S100P, regenerating islet-derived 3ß, 14-3-3 σ, and prostate stem cell antigen immunochemistry. Type 2 diabetes-like syndrome, accompanied by chronic pancreatitis, enhanced nuclear localization of S100P. Both risk factors for pancreatic cancer also induced the production of Muc5ac and the nuclear localization of S100P [corrected]. These results demonstrate that diabetes and chronic pancreatitis jointly enhance BrdU incorporation and production of pancreatic cancer-specific proteins in PDGs. The observed alterations suggest that pancreatic tumors might originate from the newly discovered histomorphological structures, called PDGs, which could represent a target for future anticancer therapies.
Asunto(s)
Carcinoma Ductal Pancreático/patología , Conductos Pancreáticos/patología , Neoplasias Pancreáticas/patología , Animales , Bromodesoxiuridina/metabolismo , Carcinoma Ductal Pancreático/complicaciones , Ceruletida , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/patología , Humanos , Masculino , Metaplasia , Ratones , Ratones Obesos , Mucinas/biosíntesis , Proteínas de Neoplasias/metabolismo , Conductos Pancreáticos/metabolismo , Neoplasias Pancreáticas/complicaciones , Pancreatitis Crónica/complicaciones , Pancreatitis Crónica/patología , Factores de RiesgoRESUMEN
Acute pancreatitis (AP) can lead to a systemic inflammatory response that often results in acute lung injury and single or multiple organ failure. In a previous study we demonstrated that diabetes aggravates the local pathophysiological process during AP. In this study we explore, if diabetes also increases pancreatitis induced systemic inflammation and causes lung injury. Acute pancreatitis was induced in untreated and streptozotocin-treated diabetic mice by injection of cerulein. Systemic inflammation was studied by IL-6 ELISA in blood plasma and white blood cell count. Lung inflammation and lung injury were quantified by chloroacetate esterase staining, evaluation of the alveolar cellularity index and cleaved caspase-3 immunohistochemistry. In normoglycaemic mice AP increased the IL-6 concentration in plasma and caused lymphocytopenia. Diabetes significantly increased the IL-6 concentration in plasma and further reduced the number of lymphocytes during AP, whereas diabetes had little effect on these parameters in the absence of pancreatitis. However, diabetes only marginally increased lung inflammation and did not lead to cell death of the lung epithelium during AP. We conclude that diabetes increases parameters of systemic inflammation during AP, but that this increase is insufficient to cause lung injury.
Asunto(s)
Lesión Pulmonar Aguda/inmunología , Diabetes Mellitus Experimental/inmunología , Pancreatitis/inmunología , Neumonía/inmunología , Sepsis/inmunología , Enfermedad Aguda , Lesión Pulmonar Aguda/complicaciones , Lesión Pulmonar Aguda/patología , Animales , Caspasa 3/inmunología , Muerte Celular/inmunología , Diabetes Mellitus Experimental/complicaciones , Diabetes Mellitus Experimental/patología , Interleucina-6/inmunología , Pulmón/inmunología , Pulmón/patología , Ratones Endogámicos C57BL , Pancreatitis/complicaciones , Pancreatitis/patología , Neumonía/complicaciones , Neumonía/patología , Mucosa Respiratoria/inmunología , Mucosa Respiratoria/patología , Sepsis/complicaciones , Sepsis/patologíaRESUMEN
BACKGROUND: Today many large mammals live in small, fragmented populations, but it is often unclear whether this subdivision is the result of long-term or recent events. Demographic modeling using genetic data can estimate changes in long-term population sizes while temporal sampling provides a way to compare genetic variation present today with that sampled in the past. In order to better understand the dynamics associated with the divergences of great ape populations, these analytical approaches were applied to western gorillas (Gorilla gorilla) and in particular to the isolated and Critically Endangered Cross River gorilla subspecies (G. g. diehli). RESULTS: We used microsatellite genotypes from museum specimens and contemporary samples of Cross River gorillas to infer both the long-term and recent population history. We find that Cross River gorillas diverged from the ancestral western gorilla population ~17,800 years ago (95% HDI: 760, 63,245 years). However, gene flow ceased only ~420 years ago (95% HDI: 200, 16,256 years), followed by a bottleneck beginning ~320 years ago (95% HDI: 200, 2,825 years) that caused a 60-fold decrease in the effective population size of Cross River gorillas. Direct comparison of heterozygosity estimates from museum and contemporary samples suggests a loss of genetic variation over the last 100 years. CONCLUSIONS: The composite history of western gorillas could plausibly be explained by climatic oscillations inducing environmental changes in western equatorial Africa that would have allowed gorilla populations to expand over time but ultimately isolate the Cross River gorillas, which thereafter exhibited a dramatic population size reduction. The recent decrease in the Cross River population is accordingly most likely attributable to increasing anthropogenic pressure over the last several hundred years. Isolation of diverging populations with prolonged concomitant gene flow, but not secondary admixture, appears to be a typical characteristic of the population histories of African great apes, including gorillas, chimpanzees and bonobos.