FGF信号通路在内耳发育调控和毛细胞再生中的作用

内耳是感受听觉和平衡觉的复杂器官。在内耳发育过程中,成纤维生长因子(fibroblast growth factor, FGF)信号通路参与了听基板的诱导、螺旋神经节(statoacoustic ganglion, SAG)的发育以及Corti器感觉上皮的分化。FGF信号开启了内耳早期发育的基因调控网络,诱导前基板区域以及听基板的形成。正常表达的FGF信号分子可促进听囊腹侧成神经细胞的特化,但成熟SAG神经元释放的过量FGF5可抑制此过程,形成负反馈环路使SAG在稳定状态下发育。FGF20在Notch信号通路的调控下参与了前感觉上皮区域向毛细胞和支持细胞的分化过程,而内毛细胞分泌的FGF8可调控局部支持细胞分化为柱细胞。人类FGF信号通路异常可导致多种耳聋相关遗传病。此外,FGF信号通路在低等脊椎动物毛细胞自发再生以及干细胞向内耳毛细胞诱导过程中都起到了关键作用。本文综述了FGF信号通路在内耳发育调控以及毛细胞再生中的作用及其相关研究进展,以期为毛细胞再生中FGF信号通路调控机制的阐明奠定理论基础。     

Setting Free the Son,Setting Free the Widow: Relational Transformation in Arrernte Life-Cycle Rituals (Central Australia)

ABSTRACT

In Australian Aboriginal society, personal identity is an evolving process whose successive mutations derive from a person’s capacity to enter into new relationships. Both initiation rites and funerary practices act to mediate such relational transformations. Drawing on Spencer and Gillen’s material on the Arrernte, this paper establishes a parallel between the procedures put into effect to render a son autonomous from his mother in the course of male initiation, and those undertaken to emancipate a widow from her deceased husband. Both ritual operations introduce a relational distancing within a totality. This totality is composed of two individuals whose antecedent close physical intimacy could thwart these persons’ ability to become an autonomous agent. The rituals make the person capable of entering a new intimate relationship: marriage in the case of a son and remarriage in the case of a widow. Both procedures entail the intervention of ritual objects closely connected to an individual’s personal identity: on the one hand, the churinga, a man is joined with at the end of his initiation and which allows him to exercise responsibilities in fertility rites, and on the other hand, the decaying, contaminating corpse a husband leaves behind upon his death.     

VEGF165 induces differentiation of hair follicle stem cells into endothelial cells and plays a role in in vivo angiogenesis

Within the vascular endothelial growth factor (VEGF) family of five subtypes, VEGF165 secreted by endothelial cells has been identified to be the most active and widely distributed factor that plays a vital role in courses of angiogenesis, vascularization and mesenchymal cell differentiation. Hair follicle stem cells (HFSCs) can be harvested from the bulge region of the outer root sheath of the hair follicle and are adult stem cells that have multi‐directional differentiation potential. Although the research on differentiation of stem cells (such as fat stem cells and bone marrow mesenchymal stem cells) to the endothelial cells has been extensive, but the various mechanisms and functional forms are unclear. In particular, study on HFSCs’ directional differentiation into vascular endothelial cells using VEGF165 has not been reported. In this study, VEGF165 was used as induction factor to induce the differentiation from HFSCs into vascular endothelial cells, and the results showed that Notch signalling pathway might affect the differentiation efficiency of vascular endothelial cells. In addition, the in vivo transplantation experiment provided that HFSCs could promote angiogenesis, and the main function is to accelerate host‐derived neovascularization. Therefore, HFSCs could be considered as an ideal cell source for vascular tissue engineering and cell transplantation in the treatment of ischaemic diseases.     

Comparison of the Photo-thermal Energy Conversion Behavior of Polar Bear Hair and Wool of Sheep

The unique photo-thermal energy conversion property of polar bear hairs has long been regarded as an essential element to enable this creature to survive in extremely cold conditions.However,the relevant research was ineffectual to provide sufficient evidence of its solar energy harvesting property.In this paper,the properties of polar bear hairs were analyzed and compared systematically with those of domestic sheep wool through the measurements in the aspects of photo-thermal conversion efficiency,scanning electron microscope,fluorescence spectral and transmission of UV-visible spectra.Moreover,this study was much more focused on exploring ultraviolet utilization property of polar bear hair than previous research.The research results demonstrated that the photo-thermal property of polar bear hair was superior to those of wool fiber,especially in harvesting ultraviolet part.The potential benefits of this research lie in the development of bionic solar energy collective devices,especially in artificial solar energy collection fibers and textile products.     

Dual role for Sox2 in specification of sensory competence and regulation of Atoh1 function

The formation of inner ear sensory epithelia is believed to occur in two steps, initial specification of sensory competent (prosensory) regions followed by determination of specific cell‐types, such as hair cells (HCs) and supporting cells. However, studies in which the HC determination factor Atoh1 was ectopically expressed in nonprosensory regions indicated that expression of Atoh1 alone is sufficient to induce HC formation suggesting that prosensory formation may not be a prerequisite for HC development. To test this hypothesis, interactions between Sox2 and Atoh1, which are required for prosensory and HC formation respectively, were examined. Forced expression of Atoh1 in nonprosensory cells resulted in transient expression of Sox2 prior to HC formation, suggesting that expression of Sox2 is required for formation of ectopic HCs. Moreover, Atoh1 overexpression failed to induce HC formation in Sox2 mutants, confirming that Sox2 is required for prosensory competence. To determine whether expression of Sox2 alone is sufficient to induce prosensory identity, Sox2 was transiently activated in a manner that mimicked endogenous expression. Following transient Sox2 activation, nonprosensory cells developed as HCs, a result that was never observed in response to persistent expression of Sox2. These results, suggest a dual role for Sox2 in inner ear formation. Initially, Sox2 is required to specify prosensory competence, but subsequent down‐regulation of Sox2 must occur to allow Atoh1 expression, most likely through a direct interaction with the Atoh1 promoter. These results implicate Sox2‐mediated changes in prosensory cells as an essential step in their ability to develop as HCs. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 3–13, 2017     

Wnt通路中的部分基因在绒山羊胚胎皮肤毛囊中的表达分析

已知绒山羊毛囊的发育受Wnt等信号通路控制,但Wnt通路相关基因在绒山羊胚胎毛囊启动和生长发育过程中的表达及作用机制尚不清楚。本文采用RNA-Seq技术对45 d,55 d和65 d的绒山羊胚胎体侧皮肤进行了转录组测序,鉴定Wnt通路相关基因的表达。 RNA- Seq技术结合blast搜索,将转录组有效测序数据与云南黑山羊参考基因组序列(http://goat. kiz.ac. cn/GGD/download.htm)比对,获得了已知的Wnt通路（pathway hsa04310）中的123个相关基因（86.0%）。进而采用实时荧光定量PCR技术检测,验证了差异表达的Sfrp4、Wnt3、Wnt10a（上调）和Apc2（下调）基因在绒山羊胚胎不同时期皮肤中的表达量,初步探索了绒山羊毛囊在胚胎期启动、发育过程中,Wnt通路部分基因的表达模式,为进一步研究Wnt通路部分基因在绒山羊胚胎毛囊启动、发育过程中的作用机制提供了有意义的线索。     

Successful retrieval of mRNA from hair follicles stored at room temperature: implications for studying gene expression in wild mammals

We evaluated some products and protocols designed for reliable RNA extraction from minute tissue samples and safe tissue storage at room temperature without RNA degradation. Success of RNA retrieval was compared for varying amounts of tissue (3, 5, 10 hair follicles), stored at different temperatures (room temperature, ?20 °C) for variable durations (1, 3, 6, 12 weeks). We also compared two RNA isolation kits specialized for small samples. RNA was successfully retrieved from as few as 3 hairs stored at room temperature for up to 6 weeks, suggesting the potential for gene expression analyses on minimally invasive samples from natural populations.     

Temperature gradient from the urogenital sinus to the pouch in the pregnant marsupial quoll, Dasyurus hallucatus

1. The mechanisms utilised by the newborn quoll to move from the uterus to the teat within the pouch are unknown. The ability to sense gravity and odour have been suggested and it is possible that temperature may also assist the young in this migration.

2. An increasing temperature gradient was observed from the sinus at 28.98 °C increasing to 29.38 °C on the skin between the sinus and the pouch and further increasing to 30.96 °C within the pouch. This temperature gradient was not as apparent during lactation.

3. Hairs may also play an important role in allowing the newborn to leave the gelatinous material emanating from the uterus and travel to the pouch. The hairs form a tunnel between the sinus and the pouch and may assist the young in the moving from uterus to the pouch.