Mathematical analysis of haemopoietic grafted cell renewal and migration through the allogeneic or syngeneic mouse host

A mathematical analysis of results from kinetic studies of 125-iododeoxyuridine uptake and loss in almost all the lymphoid and non-lymphoid organs of mice is described. Applied to data gathered from a graft-versus-host reaction experiment, this analysis affords quantitative precision on the differential effects of organ alloantigens on the proliferating grafted cells. It is shown that, depending on the organ and the post-graft period, cell growth can be ascribed to alloantigen-driven cell renewal or to alloantigen-driven trapping or sequestration. Possible applications of the present approach in graft rejection monitoring are discussed.     

Novel insights into the mechanism of action of FTY720 in a transgenic model of allograft rejection: implications for therapy of chronic rejection

FTY720 is a high-affinity agonist at the sphingosine 1-phosphate receptor 1 that prevents lymphocyte egress from lymphoid tissue and prolongs allograft survival in several animal models of solid organ transplantation. In this study we used a recently developed adoptive transfer model of TCR transgenic T cells to track allospecific CD4+ T cell expansion and trafficking characteristics, cytokine secretion profiles, and surface phenotype in vivo in the setting of FTY720 administration. We report that FTY720 administration had no effect on alloantigen-driven T cell activation, proliferation, acquisition of effector-memory function, or T cell apoptosis. However, FTY720 caused a reversible sequestration of alloantigen-specific effector-memory T cells in regional lymphoid tissue associated with a decrease in T cell infiltration within the allograft and a subsequent prolongation in allograft survival. Furthermore, delayed administration of FTY720 in a cardiac model of chronic allograft rejection attenuated the progression of vasculopathy and tissue fibrosis consistent with the hypothesis that FTY720 interrupts the trafficking of activated effector-memory T cells. These data have important implications for targeting the sphingosine 1-phosphate receptor 1 in solid organ transplantation.     

Early recognition of transplantation antigens by T lymphocytes. I. Test system and cellular parameters

Within 2-4 h of interaction of parental spleen cells from naive mice or of their supernates with alloantigen-bearing F1 hybrid spleen cells, a factor called soluble early product of immune recognition (SEPIR) is secreted. SEPIR could be revealed by its ability to enhance mixed leukocyte cultures (MLC) set up in suboptimal conditions. The factor appears to be generated by parental strain T but not B lymphocytes, is active at low concentration and acts in a pulse-like fashion. Its formation is triggered by unstimulated T cells reacting with H-2 antigens; no cytokine activity of IL 1, IL 2 or interferon character could be detected. It is suggested that the formation of SEPIR within the first few hours of MLC interaction is critically related to the further development of alloantigen-driven T cell proliferation. SEPIR might thus be the earliest discernible product of alloimmune recognition.     

CD101 surface expression discriminates potency among murine FoxP3+ regulatory T cells

CD4+CD25+FoxP3+ regulatory T cells (Treg) have been shown to be protective in animal models of autoimmunity and acute graft-vs-host disease. However, owing to the functional heterogeneity among CD4+CD25+ T cells, surface markers expressed selectively on functionally active Treg would be useful for purposes of identifying and isolating such cells. We generated a rabbit mAb against murine CD101, a transmembrane glycoprotein involved in T cell activation. Among freshly isolated T cells, CD101 was detected on 25-30% of CD4+CD25+ Treg and approximately 20% of conventional memory T cells. CD101(high) Treg displayed greater in vitro suppression of alloantigen-driven T cell proliferation as compared with CD101(low) Treg. In a model of graft-vs-host disease induced by allogeneic bone marrow transplantation in vivo bioluminescence imaging demonstrated reduced expansion of donor-derived luciferase-labeled conventional T cells in mice treated with CD101(high) Treg, compared with CD101(low) Treg. Moreover, treatment with CD101(high) Treg resulted in improved survival, reduced proinflammatory cytokine levels and reduced end organ damage. Among the CD101(high) Treg all of the in vivo suppressor activity was contained within the CD62L(high) subpopulation. We conclude that CD101 expression distinguishes murine Treg with potent suppressor activity.     

控制植物器官大小的分子机理

植物器官大小是植物形态的一个重要特征并受严格的遗传调控。器官大小与两个不同的过程有关：细胞扩张和细胞分裂。分子遗传分析已经鉴定了许多基因,这些基因通过作用于其中一个或两个过程来影响器官的最终大小。某种植物个体间器官大小的差异是由控制该器官特征的基因表达水平变化引起的,通过拟南芥的遗传分析显示这些基因是如何受控制或被修饰的。以上这些资料阐明了植物如何确定继续或停止生长,同时也提供了改变植物积累生物量的方法。     

Opposing effects of anti-activation-inducible lymphocyte-immunomodulatory molecule/inducible costimulator antibody on the development of acute versus chronic graft-versus-host disease.

The functional role of inducible costimulator (ICOS)-mediated costimulation was examined in an in vivo model of alloantigen-driven Th1 or Th2 cytokine responses, the parent-into-F(1) model of acute or chronic graft-vs-host disease (GVHD), respectively. When the Ab specific for mouse ICOS was injected into chronic GVHD-induced mice, activation of B cells, production of autoantibody, and development of glomerulonephritis were strongly suppressed. In contrast, the same treatment enhanced donor T cell chimerism and host B cell depletion in acute GVHD induced host mice. Blocking of B7-CD28 interaction by injection of anti-B7-1 and anti-B7-2 Abs inhibited both acute and chronic GVHD. These observations clearly indicate that the costimulatory signal mediated by CD28 caused the initial allorecognition resulting in the clonal expansion of alloreactive T cells, whereas the costimulatory signal mediated by ICOS played a critical role in the functional differentiation and manifestation of alloreactive T cells. Furthermore, treatment with anti-ICOS Ab selectively suppresses Th2-dominant autoimmune disease.     

Mechanisms of size control

The study of organ size control is a discipline of developmental biology that is largely unexplored. Although the size of an organ or organism depends largely on cell numbers and cell size, studies have found that the simple deregulation of cell proliferation or cell growth does not necessarily lead to changes in organ size. Recent genetic screens in Drosophila suggest that mutations that do affect organ size can be classified into three broad categories on the basis of their underlying effects: patterning, proliferation, and growth. Overall, experimental data suggest that organ size might be regulated by a 'total mass checkpoint' mechanism which functions to link the regulation of cell size and cell proliferation. The mechanisms of organ size control could also be critical targets for evolutionary events or disease processes such as tumorigenesis.     

Proteomic signature of human cancer cells

We assessed proteomic profiles as biomarkers for monitoring cell phenotypes. Protein expression profiles were obtained by fluorescence two-dimensional difference gel electrophoresis (2-D-DIGE), in which quantitative ability is improved by labeling proteins with fluorescent dyes prior to electrophoresis. Integrated protein spot intensities were analyzed by a statistical approach. The proteomic data of two groups of cell lines: (1) adenocarcinoma (AC) cell lines derived from lung, pancreas and colon tissues and (2) lung cancer cell lines with different histological backgrounds, including AC, squamous cell carcinoma and small cell carcinoma, were assessed on the basis of prior biological information. Hierarchical clustering analysis and principal component analysis were used to divide the cell lines into subgroups on the basis of similarities between their protein expression profiles. The majority of cell lines were grouped according to their organ of origin or histological background. A machine-learning algorithm selected 32 protein spots that were responsible for the classification. The results indicate that proteomic data generated by 2-D-DIGE can provide a signature of essential cell phenotypes, suggesting that it might be possible to apply this technique to developing tumor markers that could identify the organ of origin of metastatic tumors and contribute to the differential diagnosis of lung cancer.     

激光捕获显微切割技术在植物基因组研究中的应用

植物的生长和发育在很大程度上取决于组织和(或)器官特异表达的基因, 但要获取某一发育阶段的特异细胞类群来进行基因表达分析又是相当困难的。近年发展起来的激光捕获显微切割技术可以在显微镜下快速准确地获取单一的细胞类群, 甚至单个细胞, 成功地解决了组织中细胞的异质性问题。介绍了该技术的原理, 并对其在植物中的应用进展情况做了综述, 同时指出了该技术在植物中应用的可能发展方向。     

Structure and Development of Stomata in Vegetative and Floral Organs of Three Species of Kalanchoe

The structure and ontogeny of stomata in vegetative and floralorgans of three species of Kalanchoe is described. The matureanisocytic stomata are mono-cyclic or completely or incompletelyamphicyclic, rarely paracytic, transitional between paracyticand anisocytic and with a single subsidiary cell. The developmentof all the types is syndetocheilic or mesogenous from organto organ but the mature stomatal apparatus varies from organto organ as regards the number and arrangement of subsidiarycells. Abnormal stoma with a single guard cell and arresteddevelopment were observed on all organs. An abnormal stoma witha single guard cell develops directly from the meristemoid.     

鲶鱼（Parasilurus asotus）小窝器官胚胎后发育的定量研究

鲶鱼的小窝器官(电感觉器官)、其壶和感觉毛细胞的数量在胚胎后有很大增长,新的器官在一定时期内大量发生,单个器官内的壶和感觉毛细胞的数量则持续增加,器官形态有较大变化。本文统计了不同体长的鲶鱼三者的数量变化。实验表明,器官、壶和毛细胞可分别从2.5厘米体长时的1400、1400和8400增加到55厘米体长时的2.5万、20万和120万。这种数量的增长,特别是感觉毛细胞在胚胎后的增长机制和发生条件是值得注意的。本文研究了小窝器官的神经支配模式。     

Increased leaf mesophyll porosity following transient retinoblastoma‐related protein silencing is revealed by microcomputed tomography imaging and leads to a system‐level physiological response to the altered cell division pattern

The causal relationship between cell division and growth in plants is complex. Although altered expression of cell‐cycle genes frequently leads to altered organ growth, there are many examples where manipulation of the division machinery leads to a limited outcome at the level of organ form, despite changes in constituent cell size. One possibility, which has been under‐explored, is that altered division patterns resulting from manipulation of cell‐cycle gene expression alter the physiology of the organ, and that this has an effect on growth. We performed a series of experiments on retinoblastoma‐related protein (RBR), a well characterized regulator of the cell cycle, to investigate the outcome of altered cell division on leaf physiology. Our approach involved combination of high‐resolution microCT imaging and physiological analysis with a transient gene induction system, providing a powerful approach for the study of developmental physiology. Our investigation identifies a new role for RBR in mesophyll differentiation that affects tissue porosity and the distribution of air space within the leaf. The data demonstrate the importance of RBR in early leaf development and the extent to which physiology adapts to modified cellular architecture resulting from altered cell‐cycle gene expression.     

Oriented cell division in vertebrate embryogenesis

Tissue morphogenesis depends on the spatial arrangement of cells during development. A number of mechanisms have been described to contribute to the final shape of a tissue or organ, ranging from cell intercalation to the response of cells to chemotactic cues. One such mechanism is oriented cell division. Oriented cell division is determined by the position of the mitotic spindle. Indeed, there is increasing evidence implicating spindle misorientation in tissue and organ misshaping, which underlies disease conditions such as tumorigenesis or polycystic kidneys. Here we review recent studies addressing how the direction of tissue growth is determined by the orientation of cell division and how both extrinsic and intrinsic cues control the position of the mitotic spindle.     

PAR-1 is required for morphogenesis of the Caenorhabditis elegans vulva

The Caenorhabditis elegans vulva provides a simple model for the genetic analysis of pattern formation and organ morphogenesis during metazoan development. We have discovered an essential role for the polarity protein PAR-1 in the development of the vulva. Postembryonic RNA interference of PAR-1 causes a protruding vulva phenotype. We found that depleting PAR-1 during the development of the vulva has no detectable effect on fate specification or precursor proliferation, but instead seems to specifically alter morphogenesis. Using an apical junction-associated GFP marker, we discovered that PAR-1 depletion causes a failure of the two mirror-symmetric halves of the vulva to join into a single, coherent organ. The cells that normally form the ventral vulval rings fail to make contact or adhere and consequently form incomplete toroids, and dorsal rings adopt variably abnormal morphologies. We also found that PAR-1 undergoes a redistribution from apical junctions to basolateral domains during morphogenesis. Despite a known role for PAR-1 in cell polarity, we have observed no detectable differences in the distribution of various markers of epithelial cell polarity. We propose that PAR-1 activity at the cell cortex is critical for mediating cell shape changes, cell surface composition, or cell signaling during vulval morphogenesis.     

Founder cell specification

Lateral organs arise from individual or groups of cells either on the flanks of meristems or within defined cellular positional contexts. The first event in organogenesis is founder cell specification. Auxin is one necessary signal in different organ specification contexts, but it is difficult to distinguish between correlative and causal signals and evidence is emerging that other signals exist and that the interplay between these signals is important for organ initiation. This review analyses the progress in understanding which signals contribute to founder cell specification and outlines the emerging complexities in the perception of positional information that are context-dependent and reliant on the establishment and coordination of different types of competencies.     

Organ size control by Hippo and TOR pathways

The determination of final organ size is a highly coordinated and complex process that relies on the precise regulation of cell number and/or cell size. Perturbation of organ size control contributes to many human diseases, including hypertrophy, degenerative diseases, and cancer. Hippo and TOR are among the key signaling pathways involved in the regulation of organ size through their respective functions in the regulation of cell number and cell size. Here, we review the general mechanisms that regulate organ growth, describe how Hippo and TOR control key aspects of growth, and discuss recent findings that highlight a possible coordination between Hippo and TOR in organ size regulation.     

Experimental Studies on Hemopoiesis in the Pronephros of Rana pipiens

Embryogenesis of hemopoietic cell populations in the pronephros of Rana pipiens was examined during embryonic and early larval development. Differential cell counts of Wright-Giemsa-stained cell suspensions demonstrated that granulopoiesis is the predominant hemopoietic activity in the pronephros, erythropoiesis accounts for a minor component of the hemopoietic activity (> 10%), and lymphopoiesis within the organ is negligible. Microdensitometric analysis of Feulgen-DNA stained granulocyte populations in pronephroses from larvae that had received chromosomally labeled pronephric anlagen transplants between 84 and 96 h of development demonstrated that hemopoiesis in this organ is dependent on colonization by an extrinsic hemopoietic stem cell. A similar analysis of pronephric hemopoiesis in larvae which had received chromosomally labeled, presumptive ventral blood island transplants between 62 and 67 h of development, indicates that granulopoietic cells are not derived from the embryonic blood islands. It is proposed that the pronephros may be the initial site of granulocyte differentiation during early embryogenesis. Although the embryonic origin of the hemopoietic stem cell is unknown, indirect evidence from this study indicates a dorsal stem cell compartment     

Experimental studies on hemopoiesis in the pronephros of Rana pipiens.

Embryogenesis of hemopoietic cell populations in the pronephros of Rana pipiens was examined during embryonic and early larval development. Differential cell counts of Wright-Giemsa-stained cell suspensions demonstrated that granulopoiesis is the predominant hemopoietic activity in the pronephros, erythropoiesis accounts for a minor component of the hemopoietic activity (less than 10%), and lymphopoiesis within the organ is negligible. Microdensitometric analysis of Feulgen-DNA stained granulocyte populations in pronephroses from larvae that had received chromosomally labeled pronephric analgen transplants between 84 and 96 h of development demonstrated that hemopoiesis in this organ is dependent on colonization by an extrinsic hemopoietic stem cell. A similar analysis of pronephric hemopoiesis in larvae which had received chromosomally labeled, presumptive ventral blood island transplants between 62 and 67 h of development, indicates that granulopoietic cells are not derived from the embryonic blood islands. It is proposed that the pronephros may be the initial site of granulocyte differentiation during early embryogenesis. Although the embryonic origin of the hemopoietic stem cell is unknown, indirect evidence from this study indicates a dorsal stem cell compartment.