RESUMEN
G-CSF is an essential cytokine that regulates proliferation and differentiation of granulocytes from hematopoietic stem and progenitor cells. In mammals G-CSF has been identified as a key factor that promotes the release of neutrophils from the bone marrow into the blood circulation. In silico analysis indicates that zebrafish has two gcsf genes, gcsf-chr12 in chromosome 12 and gcsf-chr19 in chromosome 19. Gcsf-Chr12 participates in emergency myelopoiesis, but, in contrast to its mammalian orthologue, is not involved in neutrophil migration toward damaged tissue. In turn, the function of Gcsf-Chr19 has not been examined yet. In this study, we analyzed the role of Gcsf-Chr19 in regulating neutrophil migration toward the wound. Our results indicated that during the first h after caudal fin transection, neutrophils migrate from the hematopoietic tissue toward the injury, using the extracellular matrix as a substrate. Later, between 3 and 4 h postdamage, the recruitment mainly occurs through the bloodstream, and only a few neutrophils still use the extracellular matrix to migrate. During this process, the transcriptional levels of gcsf-chr19 are considerably increased, reaching a peak 1 h postdamage. The knockdown of Gcsf-chr19 indicated that the percentage of neutrophils that reach the wound decreased after the first h postinjury, suggesting that the knockdown specifically affects neutrophils that travel to the wound through blood vessels. Together, our data provide novel information about the regulation of neutrophil migration in zebrafish, positioning Gcsf-Chr19 as a key signal during the course of an inflammatory process triggered by severe damage.
Asunto(s)
Movimiento Celular/inmunología , Factor Estimulante de Colonias de Granulocitos/inmunología , Infiltración Neutrófila/inmunología , Neutrófilos/inmunología , Proteínas de Pez Cebra/inmunología , Pez Cebra/inmunología , Animales , Movimiento Celular/genética , Técnicas de Silenciamiento del Gen , Factor Estimulante de Colonias de Granulocitos/genética , Neovascularización Fisiológica/genética , Neovascularización Fisiológica/inmunología , Infiltración Neutrófila/genética , Neutrófilos/patología , Transducción de Señal/genética , Transducción de Señal/inmunología , Factores de Tiempo , Transcripción Genética/genética , Transcripción Genética/inmunología , Heridas y Lesiones/genética , Heridas y Lesiones/inmunología , Heridas y Lesiones/patología , Pez Cebra/genética , Proteínas de Pez Cebra/aislamiento & purificaciónRESUMEN
The necessary replacement of fish meal with other protein source in diets of commercially important fish has prompted the study of the effect of the inclusion of different vegetable proteins sources on growth performance and on the gastro-intestinal tract. Currently, soybean meal is the primary protein source as a fish meal replacement because of its low price and high availability. Likewise, it is been documented that the ingestion of soybean meal by several fish species, such as salmonids and carp, triggers a type of intestinal inflammation called enteritis. In this paper, we analyzed the effects of the ingestion of soybean meal and two of its components, soy protein and soy saponin, on zebrafish to establish the basis for using zebrafish larvae as a model for fish nutrition. We took advantage of the existence of different transgenic lines, which allowed us to perform in vivo analysis. Our results indicated that larvae that were feed with soybean meal developed a clear intestinal inflammation as early as two day after beginning the diet. Moreover, we determined that is not the soy protein present in the diet but the soy saponin that is primarily responsible for triggering the immune response. These findings support the use of zebrafish screening assays to identify novel ingredients that would to improved current fish diets or would formulate new ones.