Epigenetic Modification Agents Improve Gene-Specific Methylation Reprogramming in Porcine Cloned Embryos
PLOS ONE
Authors: Huan, Yanjun; Wu, Zhanfeng; Zhang, Jiguang; Zhu, Jiang; Liu, Zhonghua; Song, Xuexiong
Abstract
Incomplete DNA methylation reprogramming in cloned embryos leads to poor cloning efficiency. Epigenetic modification agents can improve genomic methylation reprogramming and the development of cloned embryos, however, the effect of epigenetic modification agents on gene-specific methylation reprogramming remains poorly studied. Here, we investigated DNA methylation reprogramming of pluripotency (Oct4) and tissue specific (Thy1) genes during early embryo development in pigs. In this study, we found that compared with in vitro fertilized counterparts, cloned embryos displayed the disrupted patterns of Oct4 demethylation and Thy1 remethylation. When 5-aza-2'-deoxycytidine (5-aza-dC) or trichostatin A (TSA) enhanced the development of cloned embryos, the transcripts of DNA methyltransferases (Dnmt1 and Dnmt3a), histone acetyltransferase 1 (Hat1) and histone deacetylase 1 (Hdac1) and the methylation and expression patterns of Oct4 and Thy1 became similar to those detected in in vitro fertilized counterparts. Further studies showed that Dnmt1 knockdown in cloned embryos enhanced the methylation reprogramming of Oct4 and Thy1 and promoted the activation of Oct4 and the silence of Thy1. In conclusion, our results demonstrated that cloned embryos displayed incomplete gene-specific methylation reprogramming and disrupted expression patterns of pluripotency and tissue specific genes, and epigenetic modification agents improved gene-specific methylation reprogramming and expression pattern by regulating epigenetic modification related genes. This work would have important implications in improving cloning efficiency.
Activation of neuronal Ras-related C3 botulinum toxin substrate 1 (Rac1) improves post-stroke recovery and axonal plasticity in mice
JOURNAL OF NEUROCHEMISTRY
Authors: Bu, Fan; Munshi, Yashasvee; Furr, J. Weldon; Min, Jia-wei; Qi, Li; Patrizz, Anthony; Spahr, Zachary R.; Urayama, Akihiko; Kofler, Julia K.; McCullough, Louise D.; Li, Jun
Abstract
Long-term disability after stroke is common but the mechanisms of post-stroke recovery remain unclear. Cerebral Ras-related C3 botulinum toxin substrate (Rac) 1 contributes to functional recovery after ischemic stroke in mice. As Rac1 plays divergent roles in individual cell types after central neural system injury, we herein examined the specific role of neuronal Rac1 in post-stroke recovery and axonal regeneration. Young male mice were subjected to 60-min of middle cerebral artery occlusion (MCAO). Inducible deletion of neuronal Rac1 by daily intraperitoneal injection of tamoxifen (2 mg/40 g) into Thy1-creER/Rac1-floxed mice day 7-11 after MCAO worsened cognitive (assayed by novel object recognition test) and sensorimotor (assayed by adhesive removal and pellet reaching tests) recovery day 14-28 accompanied with the reduction of neurofilament-L (NFL) and myelin basic protein (MBP) and the elevation of glial fibrillary acidic protein (GFAP) in the pert-infarct zone assessed by immunostaining. Whereas the brain tissue loss was not altered assayed by cresyl violet staining. In another approach, delayed overexpression of neuronal Rac1 by injection of lentivirus encoding Rac1 with neuronal promotor into both the cortex and striatum (total 4 mu l at 1 x 10(9) transducing units/mL) of stroke side in C57BL/6J mice day 7 promoted stroke outcome, NFL and MBP regrowth and alleviated GFAP invasion. Furthermore, neuronal Rac1 over-expression led to the activation of p21 activating kinases (PAK) 1, mitogen-activated protein kinase kinase (MEK) 1/2 and extracellular signal-regulated kinase (ERK) 1/2, and the elevation of brain-derived neurotrophic factor (BDNF) day 14 after stroke. Finally, we observed higher counts of neuronal Rac1 in the pert-infarct zone of subacute/old ischemic stroke subjects. This work identified a neuronal Rac1 signaling in improving functional recovery and axonal regeneration after stroke, suggesting a potential therapeutic target in the recovery stage of stroke.