RESUMEN
Induced pluripotent stem (iPS) cells can be generated by forced expression of four pluripotency factors in somatic cells. This has received much attention in recent years since it may offer us a promising donor cell source for cell transplantation therapy. There has been great progress in iPS cell research in the past few years. However, several issues need to be further addressed in the near future before the clinical application of iPS cells, like the immunogenicity of iPS cells, the variability of differentiation potential and most importantly tumor formation of the iPS derivative cells. Here, we review recent progress in research into the pluripotency of iPS cells.
Asunto(s)
Células Madre Pluripotentes Inducidas/citología , Animales , Técnicas de Cultivo de Célula , Diferenciación Celular , Núcleo Celular/genética , Núcleo Celular/metabolismo , Separación Celular , Humanos , Células Madre Pluripotentes Inducidas/metabolismoRESUMEN
OCT4 is a highly conserved gene and plays an important role during early embryonic development and differentiation. Similar to human OCT4, mouse Oct4 gene generates variants. Oct4A is a master regulator of self-renewal in pluripotent stem cells. In this study, we have identified a novel Oct4 spliced variant, designated mouse Oct4B, encoding 3 isoforms, termed Oct4B-247aa, Oct4B-190aa and Oct4B-164aa. Furthermore, we have examined the expression pattern of these isoforms in non-pluripotent cells and their function in somatic cell reprogramming. The results revealed the isoforms 247aa, 164aa localized mainly in nucleus and 190aa expressed dotted in the cytoplasm. In contrast to Oct4A, Oct4B does not function in somatic reprogramming as that of Oct4A. Taken together, our data for first time described the intact coding sequence of mouse Oct4B and its function in somatic cell reprogramming. These findings will be important for further analysis of the epigenetic mechanisms of reprogramming and highlight the necessity of discriminating Oct4 isoforms in future stem cell research.
Asunto(s)
Empalme Alternativo/genética , Células Madre Embrionarias/metabolismo , Factor 3 de Transcripción de Unión a Octámeros/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Reprogramación Celular/genética , Clonación Molecular , Codón/genética , Células Madre Embrionarias/citología , Humanos , Ratones , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Factor 3 de Transcripción de Unión a Octámeros/química , Factor 3 de Transcripción de Unión a Octámeros/metabolismo , Iniciación de la Cadena Peptídica Traduccional , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Transporte de Proteínas , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ribosomas/genética , Fracciones Subcelulares/metabolismoRESUMEN
In this study, the expressions of growth hormone secretagogue receptor type 1a (GHS-R1a) in the rat dorsal root ganglion (DRG) and nodose ganglion (NG) were investigated by using immunohistochemistry and in situ hybridization. The results clearly showed the presence of GHS-R1a mRNA and GHS-R1a-positive neurons in the rat DRG and NG. GHS-R1a was also co-localized with calcitonin gene-related peptide (CGRP) in some DRG and NG neurons, indicating the existence of subpopulations of the visceral afferents. The extrinsic primary afferent visceroceptive DRG and NG neurons from the stomach were identified by retrograde tracing fluorogold and stained for GHS-R1a and CGRP. Some neurons both positive for CGRP and GHS-Rla were labled by fluorogold. Our results not only demonstrate the expression of GHS-R1a in the vagal afferents but also provide the first and direct morphological evidence for its presence in the spinal visceral afferents, and gherin might have a modulatory role in the visceral afferent signaling.
Asunto(s)
Vías Aferentes , Ganglios Espinales/citología , Ganglio Nudoso/citología , Receptores de Ghrelina/metabolismo , Animales , Péptido Relacionado con Gen de Calcitonina/metabolismo , Inmunohistoquímica , Neuronas Aferentes/citología , Ratas , Estómago/inervaciónRESUMEN
OBJECTIVE: To investigate the expression of motilin-immunoreactive neurons in the hypothalamus and the effect of central administration of erythromycin (EM) on the regulation of gastric motility in diabetic rats. METHODS: The motilin immunoreactive neurons in the hypothalamus and the hippocampus were detected by immunohistochemistry with rabbit anti-motilin polyclonal antibody. To measure the gastric motility, force transducers were surgically affixed to the gastric serosa. A microinjection syringe was connected via a plastic tube to an injection cannula, which was connected with a stainless steel guide cannula. The syringe was inserted into the right lateral cerebral ventricle for microinjecting the chemicals. RESULTS: Diabetic mellitus was successfully induced in cohorts of rats. Motilin-immunoreactive neurons significantly increased in the paraventricular (PVN) and supraoptic nuclei (SON) of the hypothalamus in the diabetic rats. Intracerebroventricular (i.c.v.) administration of EM, a motilin receptor agonist, stimulated the gastric motility of diabetic rats. EM (91.56 nmol, i.c.v.) dose-dependently increased the amplitude by (174.82 +/- 48.62)% (P<0.05), and increased the frequency by (70.43 +/- 27.11)% (P < 0.05) in 5 min. The stimulatory effect lasted more than 15 min to the end of the measurement, and can be blocked partially by the prior treatment of motilin receptor antagonist GM-109. CONCLUSION: Motilin-immunoreactive neurons are increased in the PVN and SON of the hypothalamus in diabetic rats. Centrally administered EM may regulate gastric motility by binding to the central motilin receptors, and central motilin might be involved in regulation of gastric motility in diabetic rats.