Bioscience

Stem Cells can be Harvested from a Single Hair Follicle

Hair follicle stem cells (HFSCs) are potentially useful for the treatment of skin injuries and diseases. To achieve clinical application, a prerequisite must be accomplished: harvesting enough HFSCs from limited skin biopsy. The commonly used sorting approach for isolating HFSCs, however, suffers from its intrinsic disadvantages such as requirement of large-scale skin biopsy. Dr. Duan Enkui’s lab of the Institute of Zoology, CAS reported an efficient organ culture method to isolate and expand rat HFSCs from limited skin biopsy and these HFSCs could reconstitute the epidermis and the hair follicles (HFs). 73% of cultured HFs formed hair follicle stem cell colonies from the bulge, and a single hair follicle provided all the HFSCs used in this research, demonstrating the high efficiency of this method. Quantitative RT-PCR and immunofluorescent staining results revealed that these stem cells obtained from the bulge highly expressed basal layer markers K14 and alpha-6 integrin, epithelial stem cell marker P63 and bulge stem cell marker K15. After long-term culture in vitro, GFP-labeled hair follicle stem cells formed new hair follicles, epidermis, and sebaceous glands following xeno-transplantation into the back of nude mice. This study indicated that multipotent hair follicle stem cells could be efficiently harvested through organ culture from limited skin material—even a single hair follicle—and reconstitute hair follicles in vivo after long-term expansion culture, providing the basis for future clinical applications.This original article was published on line on Cell Transplantation on 24th April.

A Preliminary Investigation on Aneuploid Syndromes Using iPSCs

A group led by Drs. Pei Duanqing and Miguel Esteban successfully established induced pluripotent stem cells derived from Turner syndrome, Warkany syndrome, Patau syndrome and Emanuel syndrome, showing that the iPSCs can be generated from aneuploid cells, and the aneuploid cell-derived iPSCs displayed the self-renewal ability and pluripotency. Further, they explored the effect of aneuploidy on the early embyonic development with Turner syndrome-derived iPSC, and found that CSF2RA, a placental gene, was expressed significantly lower than that in normal iPSC during the early differentiation in vitro, implying that the low expression of some key genes may be a cause of impaired placentation of Turner syndrome,which finally results in abortion. The establishment of aneuploid iPSCs paves the way for the exploration of the early development in aneuploid embryos. The relevant work published in Human Molecular Genetics on Jan. 1, 2012.

A Bacterial Protein Mutes Plant Innate Immunity

Xanthomonas campestris pv campestris (Xcc) is a causal agent of black rot diseases on numerous crucifer plants such as Brassica and Arabidopsis. The type III effector protein AvrAC exists in all sequenced strains of Xcc. Using the Arabidopsis-Xcc as a model system, Zhou Jianmin’s group of the State Key Laboratory of Plant Genomics at the Institute of Genetics and Developmental Biology, CAS teamed up with He Chaozu’s group at Hainan University to discover an unique mechanism by which AvrAC attacks plant immune system. This protein inhibits plant immunity and enhances Xcc virulence in Arabidopsis by specifically targeting Arabidopsis BIK1 and RIPK, two receptor-like cytoplasmic kinases known to mediate immune signaling. Molecular and biochemical analyses revealed that AvrAC is an uridylyltransferase that uridylylates the conserved serine and threonine residues in the activation loop of BIK1 and RIPK. The uridylylation on these residues masks the phosphorylation sites, inhibits the kinase activity, and blocks downstream signaling. AvrAC is the first effector protein known to possess uridylyltransferase activity. The work illustrates a unique biochemical mechanism by which the Xcc bacterium combats the plant innate immune system.This work was published online in Nature on April 15 (Doi:10.1038/nature10962).