人类自然杀伤细胞活化性配体ULBPs的表达与调控

人类自然杀伤细胞活化性配体UL16结合蛋白(UL16-binding proteins,ULBPs)家族至少由6个成员组成,其中ULBP1、ULBP2、ULBP3(ULl6-binding protein 1-3)分子含有α1和α2结构域,通过糖基磷脂酰肌醇(giycosylphosphatidylinositol,GPI)与细胞膜相连。ULBP4(UL16-binding protein 4)分子含有跨膜和胞质结构域。正常组织中广泛表达ULBPs。T淋巴细胞瘤、结肠癌、卵巢癌等肿瘤细胞表面也有ULBPs的高表达。化学药物、细胞因子、细菌和病毒感染等众多因素都可以调控ULBPs的表达,其中紫外线辐射、化疗药物等诱发的DNA损伤反应可以活化3-磷脂酰肌醇激酶家族类成员(ataxia-telangiecta- sia mutated,ATM)或(ataxia-telangiectasia and Rad3-related,ATR)激酶,进一步活化下游的Chk1、Chk2节点激酶和其他的凋亡相关分子,从而诱导ULBPs的表达,引起肿瘤细胞的生长周期停滞,诱导细胞凋亡,发挥抗肿瘤作用。另外,ULBP1启动子中CRE1位点活化也是上调ULBP1转录和表达的关键因素。对ULBPs表达与调控因素的深入探讨将为阐明肿瘤逃逸机制、寻求抗肿瘤有效药物提供新的作用靶点和思路。

Epidemiology and gene markers of ulcerative colitis in the Chinese

Inflammatory bowel disease （IBD） includes two similar yet distinct conditions called ulcerative colitis （UC） and Crohn＇s disease （CD）. These diseases affect the digestive system and cause the inflammation of intestinal tissue, form sores and bleed easily. Most children with IBD are diagnosed in late childhood and adolescence. However, both UC and CD have been reported as early as in infancy. Most information pertaining to the epidemiology of IBD is based upon adult studies. Symptoms include abdominal pain, cramping, fatigue and diarrhea. Genetic factors play a significant role in determining IBD susceptibility. Epidemiological data support a genetic contribution to the pathogenesis of IBD. Recently, numerous new genes have been identified as being involved in the genetic susceptibility to IBD： TNF- 308A, CARD15 （NOD2）, MIF-173, N-acetyltransferase 2 （NAT2）, NKG2D （natural killer cell 2D）, STAT6 （signal transducer and activator of transcription 6）, CTLA-4 （cytotoxic T lymphocyte antigen-4）, MICA-MICB （major histocompatibility complex A and B）, HLA-DRB1, HLA class-Ⅱ, IL-18, IL-4, MICA-A5, CD14, TI R4, Fas-670, p53 and NF-kB. The characterization of these novel genes has the potential to identify therapeutic agents and aid clinical assessment of phenotype and prognosis in patients with IBD （UC and CD）.

Expression of prolactin receptor and response to prolactin stimulation of human NK cell lines

We have previously shown a critical role of prolactin (PRL) during maturation and anti-tumor effects of murine natural killer (NK) cells in vitro and in vivo. We extended that study by exploring the ability of human NK cell lines (NK-92 and YT cell) to express PRL receptor (PRL-R) and to respond to PRL stimulation in vitro. Both human NK cell lines constitutively expressed PRL-R on membrane and mRNA transcripts,NK-92 cells contained higher level of PRL-R than YT cells,which correlated to the enhanced capacity of the cells to proliferate and to lyse target cells in response to PRL stimulation in the presence of trace amount of IL-2 or IL-15 in vitro. Two differences between IL-2 and IL-15 in functioning on human NK cells were for the first time observed. PRL synergized with IL-15 to improve proliferation of NK cells in a dose-dependent manner without double peak manifesting like IL-2. Although PRL enhanced the cytotoxicity of IL-2 or IL- 15 activated NK cells,it exerted the function through up-regulating gene expression of perforin without influence of FasL in IL-2-stimulated NK cells,while in IL-15-stimulated NK cells,PRL did the function through up-regulating gene expression of both perforin and FasL but not IFNγ. PRL increased expressions of IL-2Rα on membrane and of IL-2 mRNA in cells,indicating that PRL up-regulated NK cell function by improving positive feedback between IL-2 and IL-2R. The similar results were also observed in network between IL-15 and IL-15R. These data indicate a potential role of PRL in human NK cell modulation.