Polyamines from myeloid-derived suppressor cells promote Th17 polarization and disease progression

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Stem cells in prostate cancer initiation and progression

Peter Nowell and David Hungerford's discovery of the Philadelphia chromosome facilitated many critical studies that have led to a paradigm shift in our understanding of cancer as a disease of stem cells. This Review focuses on the application of these concepts to investigation of the role of stem cells in prostate cancer initiation and progression. Major strides in the development of in vitro and in vivo assays have enabled identification and characterization of prostate stem cells as well as functional evaluation of the tumorigenic effects of prostate cancer-related genetic alterations.     

Regulatory B cells are identified by expression of TIM-1 and can be induced through TIM-1 ligation to promote tolerance in mice

T cell Ig domain and mucin domain protein 1 (TIM-1) is a costimulatory molecule that regulates immune responses by modulating CD4+ T cell effector differentiation. However, the function of TIM-1 on other immune cell populations is unknown. Here, we show that in vivo in mice, TIM-1 is predominantly expressed on B rather than T cells. Importantly, TIM-1 was expressed by a large majority of IL-10-expressing regulatory B cells in all major B cell subpopulations, including transitional, marginal zone, and follicular B cells, as well as the B cell population characterized as CD1d(hi)CD5+. A low-affinity TIM-1-specific antibody that normally promotes tolerance in mice, actually accelerated (T cell-mediated) immune responsiveness in the absence of B cells. TIM-1+ B cells were highly enriched for IL-4 and IL-10 expression, promoted Th2 responses, and could directly transfer allograft tolerance. Both cytokine expression and number of TIM-1+ regulatory B cells (Bregs) were induced by TIM-1-specific antibody, and this was dependent on IL-4 signaling. Thus, TIM-1 is an inclusive marker for IL-10+ Bregs that can be induced by TIM-1 ligation. These findings suggest that TIM-1 may be a novel therapeutic target for modulating the immune response and provide insight into the signals involved in the generation and induction of Bregs.     

Regulatory T cells inhibit stable contacts between CD4+ T cells and dendritic cells in vivo

Regulatory T (T reg) cells exert powerful down-modulatory effects on immune responses, but it is not known how they act in vivo. Using intravital two-photon laser scanning microscopy we determined that, in the absence of T reg cells, the locomotion of autoantigen-specific T cells inside lymph nodes is decreased, and the contacts between T cells and antigen-loaded dendritic cells (DCs) are of longer duration. Thus, T reg cells can exert an early effect on immune responses by attenuating the establishment of stable contacts during priming of naive T cells by DCs.     

Role of Toll-like receptor 4 in the initiation and progression of atherosclerotic disease

The family of Toll-like receptors (TLRs) initiates an innate immune response after recognition of pathogen-associated molecular patterns (PAMPs). Evidence is accumulating that TLRs, and particularly TLR4, are important players in the initiation and progression of atherosclerotic disease. Not only exogenous ligands but also endogenous ligands that are expressed during arterial injury are recognized by TLR4. Mouse knockout studies and epidemiological studies of human TLR4 polymorphisms have demonstrated that the TLR4 might play a role in the initiation and progression of atherosclerosis. This review will summarize the latest progression in research on the role of TLR4 in arterial occlusive disease In addition, the potential of intervention in TLR4 signalling to influence progression of atherosclerotic disease is discussed.     

调节性B细胞在免疫性血小板减少症发病过程中的意义

本研究旨在探讨调节B细胞（Breg）在免疫性血小板减少症（ITP）发病中的作用及其临床意义。采用流式细胞术检测35例已确诊的ITP患者及20例正常对照的CD19＋CD24hi CD38hi B细胞的表达率,应用RT—PCR检测患者IL-10mRNA、TGF-β1mRNA细胞因子的表达水平。结果表明,初诊ITP患者外周血CD19＋ CD24hi CD38hi B细胞的表达率明显低于正常对照组,差异有统计学意义（P〈0．05）;治疗后血小板数升高的ITP患者的CD19＋ CD24hi CD38hi B细胞的表达率高于治疗前的ITP患者,且差异有统计学意义（P〈0．05）;初诊ITP患者IL-10mRNA的表达明显低于正常对照组（P〈0．05）,治疗后的ITP患者IL-10mRNA的表达明显升高,且与治疗前相比差异有统计学意义（P〈0．05）;初诊ITP患者TGF-β1mRNA的表达高于正常对照组（P〈0．05）,ITP患者经治疗后TGF—β1mRNA的表达下降,且差异均有统计学意义（P〈0．05）。结论：Breg细胞通过体液免疫及对T淋巴细胞的调节在ITP发病机制中可能有重要作用。     

Plasmacytoid dendritic cells inhibit pulmonary immunopathology and promote clearance of respiratory syncytial virus

Respiratory syncytial virus (RSV) infection is widely spread and is a major cause of bronchiolitis in infants and high-risk adults, often leading to hospitalization. RSV infection leads to obstruction and inflammation of the airways and induction of innate and acquired immune responses. Because dendritic cells (DCs) are essential in the elicitation of these immune responses, we investigated the presence and the role of dendritic cell subtypes upon RSV infection in the lung. Here, we report that RSV infection increased the number of both conventional and plasmacytoid dendritic cells in the lung and the lung-draining lymph nodes. In particular, the increase in plasmacytoid dendritic cell numbers was sustained and lasted until 30 d after infection. Depletion of plasmacytoid dendritic cells resulted in decreased RSV clearance. In addition, depletion of plasmacytoid dendritic cells resulted in an exacerbation of all manifestations of immune-mediated pathology caused by RSV infection. In conclusion, this study demonstrates that both conventional and plasmacytoid dendritic cells are attracted to the site of RSV infection. It is demonstrated that plasmacytoid dendritic cells play a protective role during RSV infection by modulation of local immune responses.     

Spontaneous relapsing-remitting EAE in the SJL/J mouse: MOG-reactive transgenic T cells recruit endogenous MOG-specific B cells

We describe new T cell receptor (TCR) transgenic mice (relapsing-remitting [RR] mice) carrying a TCR specific for myelin oligodendrocyte glycoprotein (MOG) peptide 92–106 in the context of I-A^s. Backcrossed to the SJL/J background, most RR mice spontaneously develop RR experimental autoimmune encephalomyelitis (EAE) with episodes often altering between different central nervous system tissues like the cerebellum, optic nerve, and spinal cord. Development of spontaneous EAE depends on the presence of an intact B cell compartment and on the expression of MOG autoantigen. There is no spontaneous EAE development in B cell–depleted mice or in transgenic mice lacking MOG. Transgenic T cells seem to expand MOG autoreactive B cells from the endogenous repertoire. The expanded autoreactive B cells produce autoantibodies binding to a conformational epitope on the native MOG protein while ignoring the T cell target peptide. The secreted autoantibodies are pathogenic, enhancing demyelinating EAE episodes. RR mice constitute the first spontaneous animal model for the most common form of multiple sclerosis (MS), RR MS.Autoimmune diseases can affect most organs of the body including liver, heart, the endocrine system, the musculoskeletal apparatus, and the central nervous system (CNS). They commonly start off at a young age and then last throughout life, often resulting in severe disability. The factors that trigger the onset, modulate the course, and determine the clinical character of autoimmune diseases have remained obscure, a deficit of knowledge which sets limits to the design of specific and efficient therapies.Yet there is increasing evidence that organ-specific autoimmune diseases, such as rheumatoid arthritis, type 1 diabetes mellitus, and multiple sclerosis (MS), are the result of a pathogenic interaction of autoimmune T and B cells. There is substantial information on the role of T cells in organ-specific autoimmunity. Some act as effector cells attacking self-tissues, either directly or via recruiting accessory cells like macrophages. Other T cells regulate the time course of the response and still others provide help to autoantibody-producing B cells. The contribution of autoimmune B cells to the inflammatory pathogenesis seems to be complex as well. Beyond producing humoral autoantibodies, B cells serve as APCs activating pathogenic T cells, and, through their capacity of releasing cytokines, B cells are involved in shaping local microenvironments favorable to evolving cellular autoimmune responses.Deciphering the interactions between T and B cells in the spontaneous development of organ-specific autoimmune responses requires suitable animal models. Naturally occurring models are available for type 1 diabetes mellitus and systemic lupus erythematosus but not for autoimmunity in the CNS (1). Recently, we and others described a double-transgenic mouse model, which simulates opticospinal MS (OSMS) remarkably well, a variant of which is also known as Devic''s disease (2, 3). These mice, termed opticospinal experimental autoimmune encephalomyelitis (EAE [OSE]) mice, express myelin oligodendrocyte glycoprotein (MOG)–specific receptors on T and B cells and spontaneously develop demyelinating inflammatory disease at frequencies >50%. Like in human OSMS (4), the lesions in affected mice are restricted to optic nerve and spinal cord, and, in most cases, the disease takes a chronic progressive course without remissions and marked relapses. It should, however, be noted that the type of MS that most prevalently affects Caucasian populations differs fundamentally from OSMS (5). Typically, MS starts out with a relapsing-remitting (RR) course, where disease episodes may completely resolve only to be followed by a subsequent relapse. In this disease variant, the pathogenic lesions, demyelinating plaques, may be located throughout the CNS, thus causing the notoriously varied neurological defect patterns.In this paper, we describe a new transgenic mouse model that spontaneously develops RR-EAE and, thus, recapitulates the “Western” variant of MS. Furthermore, and most importantly, we found that in these mice transgenic autoimmune T cells expand autoimmune B cells from the endogenous immune repertoire and guide them to produce antibodies against conformational epitopes of the MOG protein, which, together with complement, may initiate the destruction of MOG-expressing target cells.     

B cells in health and disease

B cells play a key role in regulating the immune system by producing antibodies, acting as antigen-presenting cells, providing support to other mononuclear cells, and contributing directly to Inflammatory pathways. Accumulating evidence points to disruption of these tightly regulated processes in the pathogenesis of autoimmune disorders. Although the exact mechanisms involved remain to be elucidated, a fundamental feature of many autoimmune disorders is a loss of B-cell tolerance and the inappropriate production of autoantibodies. Dysfunctional immune responses resulting from genetic mutations that cause intrinsic B-cell abnormalities and induction of autoimmunity in the T-cell compartment by B cells that have broken tolerance may also contribute to these disorders. These findings provide the rationale for B-cell depletion as a potential therapeutic strategy in autoimmune disorders and other disease states characterized by inappropriate immune responses. Preliminary results with the CD20-targeted monoclonal antibody rituximab indicate that rituximab can improve symptoms in a number of autoimmune and neurologic disorders (including rheumatoid arthritis, systemic lupus erythematosus, and paraneoplastic neurologic syndromes). Additional studies are warranted to further characterize the role of B cells in autoimmune diseases and the therapeutic utility of B-cell depletion.     

Regulatory and other rheumatoid factors in rheumatoid arthritis patients with active disease or in remission

BackgroundPreviously, we identified a regulatory rheumatoid factor (regRF), the production of which provides rats with resistance to collagen‐induced arthritis (CIA). Immunization with conformers of IgG Fc fragments carrying epitopes specific to regRF reduces symptoms of CIA. The aim of this study was to determine whether there is a link between regRF levels and rheumatoid arthritis (RA) activity in humans in order to assess the potential of regRF as a therapeutic biotarget in RA. The variability of rheumatoid factor (RF) specificities present in the blood of RA patients was also studied.MethodsThe regRF were studied in RA patients with active disease and in remission. Variability in the specificities of RF associated with RA was studied by concurrent inhibition of RF latex fixation by variants of modified IgG.ResultsPatients in remission had regRF levels higher than in healthy subjects. The regRF in remission was characterized by tight binding to its antigen, as in healthy subjects. The regRF levels in patients with active RA varied dramatically, and regRF binding to its antigen was weak. The exacerbation of Still''s disease coincided with low regRF levels and affinity, while an improvement in patient condition was associated with an increase in regRF levels and affinity. The RF specific to RA, which was detected by the RF latex‐fixation method, was a nonhomogeneous population of antibodies that included RF to lyophilized IgG, to IgG immobilized on polystyrene, and to rabbit IgG.ConclusionStimulating regRF production might enable improved RA therapy.     

Myelin oligodendrocyte glycoprotein-specific T and B cells cooperate to induce a Devic-like disease in mice

Multiple sclerosis (MS) is a clinically and pathologically heterogeneous inflammatory/demyelinating disease of the CNS. In the MS variant Devic disease, lesions are predominantly found in the optic nerves and spinal cord but not the brain. The immunological bases of the different forms of MS are unknown. We previously generated myelin oligodendrocyte glycoprotein-specific (MOG-specific) TCR transgenic mice (TCRMOG mice; also referred to as 2D2 mice) and reported that a large proportion of these mice develop spontaneous isolated optic neuritis. We have now crossed the TCRMOG mice with MOG-specific Ig heavy-chain knock-in mice (IgHMOG mice; also referred to as Th mice), in which one-third of the B cells are specific for MOG. In these mice, MOG-specific B cells are very efficient in presenting MOG to the transgenic T cells and undergo class switching to IgG1 in the presence of the transgenic T cells. Sixty percent of TCRMOG x IgHMOG mice spontaneously developed a severe form of experimental autoimmune encephalomyelitis (EAE). Histological examination of the CNS revealed a selective distribution of meningeal and parenchymal inflammatory lesions in the spinal cord and optic nerves. Thus, CNS antigen-specific T and B cells cooperate to induce a distinct clinicopathologic EAE pattern that closely replicates human Devic disease.     

Progenitors for Ly-1 B cells are distinct from progenitors for other B cells

Data from previous multiparameter fluorescence-activated cell sorter (FACS) analysis and sorting studies define a subset of murine B cells that expresses the Ly-1 surface determinant in conjunction with IgM, IgD, Ia, and other typical B cell markers. These Ly-1 B cells are physically and functionally distinct. They express more IgM and less IgD than most other B cells; they are not normally found in lymph node or bone marrow; they are always present at low frequencies (1-5%) in normal spleens, and, as we show here, they comprise about half of the B cells (10-20% of total cells) recovered from the peritoneal cavity in normal mice. Furthermore, most of the commonly studied IgM autoantibodies in normal and autoimmune mice are produced by these Ly-1 B cells, even though they seldom produce antibodies to exogenous antigens such as trinitrophenyl-Ficoll or trinitrophenyl-keyhole limpet hemocyanin. Cell transfer studies presented here demonstrate that the progenitors of Ly-1 B cells are different from the progenitors of the predominant B cell populations in spleen and lymph node. In these studies, we used FACS analysis and functional assays to characterize donor-derived (allotype-marked) B cells present in lethally irradiated recipients 1-2 mo after transfer. Surprisingly, adult bone marrow cells typically used to reconstitute B cells in irradiated recipients selectively failed to reconstitute the Ly-1 B subset. Liver, spleen, and bone marrow cells from young mice, in contrast, reconstituted all B cells (including Ly-1 B), and peritoneal "washout" cells (PerC) from adult mice uniquely reconstituted Ly-1 B. Bone marrow did not block Ly-1 B development, since PerC and newborn liver still gave rise to Ly-1 B when jointly transferred with marrow. These findings tentatively assign Ly-1 B to a distinct developmental lineage originating from progenitors that inhabit the same locations as other B cell progenitors in young animals, but move to unique location(s) in adults.     

J chain biosynthesis in pre-B cells and other possible precursor B cells

Human cell lines that resemble precursors in the B cell lineage have been found to synthesize J chain. In vivo pulse labeling, together with in vitro translation of total cellular RNA in a wheat germ cell-free system, detected the synthesis of J chain in immunoglobulin-secreting cell lines, in a cell line with only surface IgM, as well as in the pre-B-like cell line Josh 4 and the round cell lines Josh 7 and KLM 2. The primary translation products of J chain from all of these cell lines were found to be indistinguishable from one another by serologic criteria, by relative mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, by charge as judged by alkaline-urea gel electrophoresis, and by peptide mapping. These findings suggest that the onset of J chain biosynthesis represents a relatively early event in B cell ontogeny, occurring before the development of immunoglobulin polymer-secreting cells. Its role may, consequently, be fundamental to the biosynthesis of all immunoglobulins, at different stages of B cell differentiation.     

PTHrP drives breast tumor initiation, progression, and metastasis in mice and is a potential therapy target

Parathyroid hormone-related protein (PTHrP) is a secreted factor expressed in almost all normal fetal and adult tissues. It is involved in a wide range of developmental and physiological processes, including serum calcium regulation. PTHrP is also associated with the progression of skeletal metastases, and its dysregulated expression in advanced cancers causes malignancy-associated hypercalcemia. Although PTHrP is frequently expressed by breast tumors and other solid cancers, its effects on tumor progression are unclear. Here, we demonstrate in mice pleiotropic involvement of PTHrP in key steps of breast cancer - it influences the initiation and progression of primary tumors and metastases. Pthrp ablation in the mammary epithelium of the PyMT-MMTV breast cancer mouse model caused a delay in primary tumor initiation, inhibited tumor progression, and reduced metastasis to distal sites. Mechanistically, it reduced expression of molecular markers of cell proliferation (Ki67) and angiogenesis (factor VIII), antiapoptotic factor Bcl-2, cell-cycle progression regulator cyclin D1, and survival factor AKT1. PTHrP also influenced expression of the adhesion factor CXCR4, and coexpression of PTHrP and CXCR4 was crucial for metastatic spread. Importantly, PTHrP-specific neutralizing antibodies slowed the progression and metastasis of human breast cancer xenografts. Our data identify what we believe to be new functions for PTHrP in several key steps of breast cancer and suggest that PTHrP may constitute a novel target for therapeutic intervention.     

Immunoglobulin gamma 2b transgenes inhibit heavy chain gene rearrangement, but cannot promote B cell development

Transgenic mice with a gamma 2b transgene were produced to investigate whether gamma 2b can replace mu in the development of B lymphocytes. Transgenic gamma 2b is present on the surface of B cells. Young transgenic mice have a dramatic decrease in B cell numbers, however, older mice have almost normal B cell numbers. Strikingly, all gamma 2b- expressing B cells in the spleen also express mu. The same is true for mice with a hybrid transgene in which the mu transmembrane and intracytoplasmic sequences replace those of gamma 2b (gamma 2b-mumem). The B cell defect is not due to toxicity of gamma 2b since crosses between gamma 2b transgenic and mu transgenic mice have normal numbers of B cells. Presence of the gamma 2b transgene strongly enhances the feedback inhibition of endogenous heavy chain gene rearrangement. Light chain genes are expressed normally, and the early expression of transgenic light chains does not improve B cell maturation. When the endogenous mu locus is inactivated, B cells do not develop at all in gamma 2b transgenic mice. The data suggest that gamma 2b cannot replace mu in promoting the developmental maturation of B cells, but that it can cause feedback inhibition of heavy chain gene rearrangement. Thus, the signals for heavy chain feedback and B cell maturation appear to be different.     

Injury initiation and progression in the anterior cruciate ligament

OBJECTIVE: To develop a theoretical model to identify mechanisms by which total and partial tears of the anterior cruciate ligament could occur. DESIGN: A sagittal-plane knee model was used to investigate anterior cruciate ligament injury due to excessive anterior tibial translation. The ligament was modelled as an ordered array of fibres linking femur and tibia. BACKGROUND: Despite years of research, the detailed biomechanics of anterior cruciate ligament injury is not well understood. METHODS: A "critical strain criterion" was used to identify the onset and progression of model ligament fibre disruption. The associated forces were also calculated. RESULTS: At low flexion angles (<20 degrees ), the posterior fibre of the model ligament failed first, and the tear progressed anteriorly through the ligament. At higher flexion angles, the anterior fibre failed first, and the tear progressed posteriorly. Near the flexion angle at which the progression of injury changed direction, all fibres failed at approximately the same anterior tibial translation. At all but very high flexion angles, the force supported by the injured ligament was maximum when initial fibre failure occurred; the force then decreased with increasing anterior tibial translation. CONCLUSIONS: Near (20 degrees ) flexion, all model anterior cruciate ligament fibres fail at approximately the same anterior tibial translation, implying that a partial ligament tear may be impossible in this flexion region. Relevance. This study provides insight into possible mechanisms of initiation and progression of anterior cruciate ligament injury. It suggests that a partial tear of the posterior half of the ligament may be difficult to detect clinically.     

Amniotic epithelial cells promote wound healing in mice through high epithelialization and engraftment

Although human amniotic epithelial cells (AMEs) are an attractive source of stem cells, their therapeutic potential in wound healing has not been fully investigated. We evaluated the therapeutic potential of AMEs for wound healing. Real‐time PCR showed that the epithelialization growth factors epidermal growth factor (EGF), platelet‐derived growth factor (PDGF)‐B and chemotactic factors interleukin‐8 (IL‐8 or CXCL8) and neutrophil‐activating protein‐2 (NAP‐2 or CXCL7) were upregulated in AMEs compared with adipose‐derived mesenchymal stem cells (ADMs). In vitro scratch wound assays revealed that AME‐derived conditioned medium substantially accelerated wound closure. Wounds in NOD/SCID mice were created by skin excision, followed by AME transplantation. AMEs implantation significantly accelerated wound healing and increased cellularity and re‐epithelialization. Transplanted AMEs exhibited high engraftment rates and expressed keratinocyte‐specific proteins and cytokeratin in the wound area, suggesting direct benefits for cutaneous closure. Taken together, these data indicate that AMEs possess therapeutic capability for wound healing through the secretion of epithelialization growth factors and enhanced engraftment properties. Copyright © 2015 John Wiley & Sons, Ltd.     

人脂肪干细胞促进小鼠随意型皮瓣血管的新生

背景：脂肪干细胞是从脂肪组织中分离提取的一种具有多向分化潜能的干细胞,对缺血性疾病的治疗有积极作用。 目的：观察局部移植人来源脂肪干细胞对小鼠随意型皮瓣成活能力及血管新生效应的影响。 方法：体外经分离、培养及传代健康成人脂肪干细胞。于SPF小鼠背部设计蒂在头侧的随意型皮瓣设为实验组,随后于皮瓣蒂部、中部、远端分3次注射脂肪干细胞悬液、并设置以同法注射等量PBS的小鼠作对照组。移植后7 d,计算各组皮瓣成活率。移植后14 d,取皮瓣组织,随机作冰冻切片CD31免疫荧光染色,荧光显微镜下观察皮瓣组织微血管分布情况,并对CM-Dil标记的脂肪干细胞示踪;ELISA法检测皮瓣组织中血管内皮生长因子水平;Western blot法检测皮瓣组织中基质细胞衍生因子1蛋白的表达。 结果与结论：与对照组相比,实验组小鼠背部随意皮瓣成活率明显提高,皮瓣组织中微血管数目明显增多,血管内皮生长因子分泌水平明显升高,基质细胞衍生因子1蛋白表达明显增多（P 〈0.05）。结果证实,人脂肪干细胞局部移植到随意型皮瓣后,可上调血管内皮生长因子和基质细胞衍生因子1的表达,促进皮瓣的血管新生。     

Lipocalin 2 is essential for chronic kidney disease progression in mice and humans

Mechanisms of progression of chronic kidney disease (CKD), a major health care burden, are poorly understood. EGFR stimulates CKD progression, but the molecular networks that mediate its biological effects remain unknown. We recently showed that the severity of renal lesions after nephron reduction varied substantially among mouse strains and required activation of EGFR. Here, we utilized two mouse strains that react differently to nephron reduction--FVB/N mice, which develop severe renal lesions, and B6D2F1 mice, which are resistant to early deterioration--coupled with genome-wide expression to elucidate the molecular nature of CKD progression. Our results showed that lipocalin 2 (Lcn2, also known as neutrophil gelatinase-associated lipocalin [NGAL]), the most highly upregulated gene in the FVB/N strain, was not simply a marker of renal lesions, but an active player in disease progression. In fact, the severity of renal lesions was dramatically reduced in Lcn2-/- mice. We discovered that Lcn2 expression increased upon EGFR activation and that Lcn2 mediated its mitogenic effect during renal deterioration. EGFR inhibition prevented Lcn2 upregulation and lesion development in mice expressing a dominant negative EGFR isoform, and hypoxia-inducible factor 1α (Hif-1α) was crucially required for EGFR-induced Lcn2 overexpression. Consistent with this, cell proliferation was dramatically reduced in Lcn2-/- mice. These data are relevant to human CKD, as we found that LCN2 was increased particularly in patients who rapidly progressed to end-stage renal failure. Together our results uncover what we believe to be a novel function for Lcn2 and a critical pathway leading to progressive renal failure and cystogenesis.