成纤维细胞激活蛋白alpha与肿瘤免疫抑制的研究进展

成纤维细胞激活蛋白alpha（Fibroblast activation protein-alpha,FAP-alpha）是一种跨膜丝氨酸蛋白酶,高度表达在90 %的上皮性肿瘤的 间质--肿瘤相关成纤维细胞（Tumor association fibroblast,TAF）上。FAPalpha在促进上皮性肿瘤的恶性进展中起着十分重要的作用, 近年来研究发现,FAP琢在肿瘤微环境中发挥免疫抑制的作用。研究FAPalpha在肿瘤免疫抑制中的作用,已成为肿瘤研究的新的热 点。为基于以FAP-alpha为靶标的抗肿瘤免疫治疗提供参考,本文围绕引起肿瘤免疫抑制的因素、FAPalpha与肿瘤免疫抑制的研究进展 以及FAP-alpha在肿瘤的发展进程的作用作一综述。     

Ex vivo Live Imaging of Lung Metastasis and Their Microenvironment

Metastasis is a major cause for cancer-related morbidity and mortality. Metastasis is a multistep process and due to its complexity, the exact cellular and molecular processes that govern metastatic dissemination and growth are still elusive. Live imaging allows visualization of the dynamic and spatial interactions of cells and their microenvironment. Solid tumors commonly metastasize to the lungs. However, the anatomical location of the lungs poses a challenge to intravital imaging. This protocol provides a relatively simple and quick method for ex vivo live imaging of the dynamic interactions between tumor cells and their surrounding stroma within lung metastasis. Using this method, the motility of cancer cells as well as interactions between cancer cells and stromal cells in their microenvironment can be visualized in real time for several hours. By using transgenic fluorescent reporter mice, a fluorescent cell line, injectable fluorescently labeled molecules and/or antibodies, multiple components of the lung microenvironment can be visualized, such as blood vessels and immune cells. To image the different cell types, a spinning disk confocal microscope that allows long-term continuous imaging with rapid, four-color image acquisition has been used. Time-lapse movies compiled from images collected over multiple positions and focal planes show interactions between live metastatic and immune cells for at least 4 hr. This technique can be further used to test chemotherapy or targeted therapy. Moreover, this method could be adapted for the study of other lung-related pathologies that may affect the lung microenvironment.     

High levels of cyclic‐di‐GMP in plant‐associated Pseudomonas correlate with evasion of plant immunity

The plant innate immune system employs plasma membrane‐localized receptors that specifically perceive pathogen/microbe‐associated molecular patterns (PAMPs/MAMPs). This induces a defence response called pattern‐triggered immunity (PTI) to fend off pathogen attack. Commensal bacteria are also exposed to potential immune recognition and must employ strategies to evade and/or suppress PTI to successfully colonize the plant. During plant infection, the flagellum has an ambiguous role, acting as both a virulence factor and also as a potent immunogen as a result of the recognition of its main building block, flagellin, by the plant pattern recognition receptors (PRRs), including FLAGELLIN SENSING2 (FLS2). Therefore, strict control of flagella synthesis is especially important for plant‐associated bacteria. Here, we show that cyclic‐di‐GMP [bis‐(3′‐5′)‐cyclic di‐guanosine monophosphate], a central regulator of bacterial lifestyle, is involved in the evasion of PTI. Elevated cyclic‐di‐GMP levels in the pathogen Pseudomonas syringae pv. tomato (Pto) DC3000, the opportunist P. aeruginosa PAO1 and the commensal P. protegens Pf‐5 inhibit flagellin synthesis and help the bacteria to evade FLS2‐mediated signalling in Nicotiana benthamiana and Arabidopsis thaliana. Despite this, high cellular cyclic‐di‐GMP concentrations were shown to drastically reduce the virulence of Pto DC3000 during plant infection. We propose that this is a result of reduced flagellar motility and/or additional pleiotropic effects of cyclic‐di‐GMP signalling on bacterial behaviour.     

PARylation of the forkhead‐associated domain protein DAWDLE regulates plant immunity

Protein poly(ADP‐ribosyl)ation (PARylation) primarily catalyzed by poly(ADP‐ribose) polymerases (PARPs) plays a crucial role in controlling various cellular responses. However, PARylation targets and their functions remain largely elusive. Here, we deployed an Arabidopsis protein microarray coupled with in vitro PARylation assays to globally identify PARylation targets in plants. Consistent with the essential role of PARylation in plant immunity, the forkhead‐associated (FHA) domain protein DAWDLE (DDL), one of PARP2 targets, positively regulates plant defense to both adapted and non‐adapted pathogens. Arabidopsis PARP2 interacts with and PARylates DDL, which was enhanced upon treatment of bacterial flagellin. Mass spectrometry and mutagenesis analysis identified multiple PARylation sites of DDL by PARP2. Genetic complementation assays indicate that DDL PARylation is required for its function in plant immunity. In contrast, DDL PARylation appears to be dispensable for its previously reported function in plant development partially mediated by the regulation of microRNA biogenesis. Our study uncovers many previously unknown PARylation targets and points to the distinct functions of DDL in plant immunity and development mediated by protein PARylation and small RNA biogenesis, respectively.     

The effect of dietary methionine levels on fattening performance and selected blood and tissue parameters of turkeys

A total of 490 eight-week-old female Hybrid Converter turkeys (body weight 4.11 ± 0.03 kg) were divided into 5 groups with 7 replicates of 14 birds each. For 8 weeks, basal diets were supplemented with methionine (Met) at following levels (weeks 9–12/weeks 13–16 of age): Group 1 – 0.34/0.29%, Group 2 – 0.39/0.34%, Groups 3 and 4 – 0.45/0.38% and 0.51/0.41%, respectively, Group 5 – 0.58/0.47%. Only in the first feeding phase the body weight gain (BWG) was affected by Met levels with the significantly highest BWG in Group 3. No treatment effects were found for feed conversion ratio, carcass yield, carcass composition and meat colour. The blood superoxide dismutase activity was significantly highest in Groups 2 and 3. The concentrations of reduced glutathione in the liver were linearly increased (p = 0.018), whereas the ratio of reduced glutathione to oxidised glutathione was highest in Group 3 (quadratic contrast, p = 0.004). It can be concluded that turkeys from Group 3 (Met levels age depending 15% and 10% above recommendations by NRC) were characterised by a well-balanced physiological response. Attention should be paid to the immune response of birds to higher dietary Met levels: plasma IgA concentrations decreased, whereas IL-6 and TNF-α levels increased in turkeys fed diets with the highest Met content.     

Effects of anti‐human T lymphocyte immune globulins in patients: new or old

Multiple studies demonstrated that anti‐human T lymphocyte immune globulins (ATG) can decrease the incidence of acute and chronic graft rejection in cell or organ transplants. However, further in‐depth study indicates that different subgroups may benefit from either different regimes or alteration of them. Studies among renal transplant patients indicate that low immunological risk patients may not gain the same amount of benefit and thus tilt the risk versus benefit consideration. This may hold true for low immunological risk patients receiving other organ transplants and would be worth further investigation. The recovery time of T cells and natural killer (NK) cells also bears consideration and the impact that it has on the severity and incidence of opportunistic infections closely correlated with the dosage of ATG. The use of lower doses of ATG in combination with other induction medications may offer a solution. The finding that ATG may lose efficacy in cases of multiple transplants or re‐transplants in the case of heart transplants may hold true for other transplantations. This may lead to reconsideration of which induction therapies would be most beneficial in the clinical setting. These studies on ATG done on different patient groups will naturally not be applicable to all, but the evidence accrued from them as a whole may offer us new and different perspectives on how to approach and potentially solve the clinical question of how to best reduce the mortality associated with chronic host‐versus‐graft disease.     

Effects of dietary addition of heat-killed Mycobacterium phlei on growth performance,immune status and anti-oxidative capacity in early weaned piglets

The contradiction between high susceptibility of early weaned piglets to enteric pathogens and rigid restriction of antibiotic use in the diet is still prominent in the livestock production industry. To address this issue, the study was designed to replace dietary antibiotics partly or completely by an immunostimulant, namely heat-killed Mycobacterium phlei (M. phlei). Piglets (n = 192) were randomly assigned to one of the four groups: (1) basal diet (Group A), (2) basal diet + a mixture of antibiotics (80 mg/kg diet, Group B), (3) basal diet + a mixture of antibiotics (same as in Group B, but 40 mg/kg diet) + heat-killed M. phlei (1.5 g/kg diet) (Group C) and (4) basal diet + heat-killed M. phlei (3 g/kg diet) (Group D). All piglets received the respective diets from days 21 to 51 of age and were weaned at the age of 28 d. Compared with the Control (Group A), in all other groups the average daily gain, average daily feed intake, small intestinal villus height:crypt depth ratio and protein levels of occludin and ZO-1 in the jejunal mucosa were increased. A decreased incidence of diarrhoea in conjunction with an increased sIgA concentration in the intestinal mucosa and serum IL-12 and IFN-γ concentrations was found in groups supplemented with heat-killed M. phlei (Groups C and D), but not in Group B. Groups C and D also showed decreased IL-2 concentrations in the intestinal mucosa with lower TLR4 and phosphor-IκB protein levels. The antioxidant capacity was reinforced in Groups C and D, as evidenced by the reduction in malondialdehyde and enhanced activities of antioxidant enzymes in serum. These data indicate that heat-killed M. phlei is a promising alternative to antibiotic use for early weaned piglets via induction of protective immune responses.