Role of G-protein-coupled adenosine receptors in downregulation of inflammation and protection from tissue damage.

Inappropriate or prolonged inflammation is the main cause of many diseases; for this reason it is important to understand the physiological mechanisms that terminate inflammation in vivo. Agonists for several Gs-protein-coupled receptors, including cell-surface adenosine purinergic receptors, can increase levels of immunosuppressive cyclic AMP in immune cells; however, it was unknown whether any of these receptors regulates inflammation in vivo. Here we show that A2a adenosine receptors have a non-redundant role in the attenuation of inflammation and tissue damage in vivo. Sub-threshold doses of an inflammatory stimulus that caused minimal tissue damage in wild-type mice were sufficient to induce extensive tissue damage, more prolonged and higher levels of pro-inflammatory cytokines, and death of male animals deficient in the A2a adenosine receptor. Similar observations were made in studies of three different models of inflammation and liver damage as well as during bacterial endotoxin-induced septic shock. We suggest that A2a adenosine receptors are a critical part of the physiological negative feedback mechanism for limitation and termination of both tissue-specific and systemic inflammatory responses.     

Gene-specific control of inflammation by TLR-induced chromatin modifications

Toll-like receptors (TLRs) induce a multi-component inflammatory response that must be tightly regulated to avoid tissue damage. Most known regulatory mechanisms target TLR signalling pathways and thus broadly inhibit multiple aspects of the inflammatory response. Given the functional diversity of TLR-induced genes, we proposed that additional, gene-specific regulatory mechanisms exist to allow individual aspects of the TLR-induced response to be differentially regulated. Using an in vitro system of lipopolysaccharide tolerance in murine macrophages, we show that TLR-induced genes fall into two categories on the basis of their functions and regulatory requirements. We demonstrate that representatives from the two classes acquire distinct patterns of TLR-induced chromatin modifications. These gene-specific chromatin modifications are associated with transient silencing of one class of genes, which includes pro-inflammatory mediators, and priming of the second class, which includes antimicrobial effectors. These findings illustrate an adaptive response in macrophages and reveal component-specific regulation of inflammation.     

Magnetic resonance imaging of pH in vivo using hyperpolarized 13C-labelled bicarbonate

As alterations in tissue pH underlie many pathological processes, the capability to image tissue pH in the clinic could offer new ways of detecting disease and response to treatment. Dynamic nuclear polarization is an emerging technique for substantially increasing the sensitivity of magnetic resonance imaging experiments. Here we show that tissue pH can be imaged in vivo from the ratio of the signal intensities of hyperpolarized bicarbonate (H(13)CO(3)(-)) and (13)CO(2) following intravenous injection of hyperpolarized H(13)CO(3)(-). The technique was demonstrated in a mouse tumour model, which showed that the average tumour interstitial pH was significantly lower than the surrounding tissue. Given that bicarbonate is an endogenous molecule that can be infused in relatively high concentrations into patients, we propose that this technique could be used clinically to image pathological processes that are associated with alterations in tissue pH, such as cancer, ischaemia and inflammation.     

甘草苷对感染后咳嗽(肺阴虚证)小鼠的止咳作用机制及抗氧化作用的研究

为探讨甘草苷对感染后咳嗽(肺阴虚证)小鼠的止咳疗效及抗氧化的作用机制.采用烟熏＋内毒素(LPS)滴鼻＋甲状腺素灌胃＋辣椒素雾化诱咳来构建感染后咳嗽(肺阴虚证)小鼠模型；造模成功后随机分为空白组(生理盐水)、模型组(生理盐水)、阳性组(孟鲁司特钠)和甘草苷低、中、高剂量组；观察造模前后各组小鼠的行为学及体质量变化，采用辣椒素雾化诱咳来测定各组小鼠的咳嗽敏感性及咳嗽次数，通过酶联免疫吸附法(ELISA)测定小鼠血清中炎症与肺组织中抗氧化损伤相关蛋白水平变化并经由苏木精-伊红(HE)染色法来观察各组小鼠的肺组织病变.结果表明，甘草苷止咳的作用机制可能为有效减少小鼠血清中TNF-α、IL-6、IL-13、TLR2、TGF-β1、IgE等细胞因子及炎性介质的释放，进而减轻气道感染性及变态性炎性反应环境来降低咳嗽高敏感性，减少对咳嗽中枢的刺激来达到止咳的目的；抗氧化的作用机制可能为有效提高小鼠肺组织中SOD的含量，减少小鼠肺组织中MDA的含量，来改善体内抗氧化平衡系统的紊乱，有效清除机体中的过量自由基，提高机体内抗氧化酶的含量，以减轻氧化损伤来达到抗氧化的目的.     

Points of control in inflammation

Inflammation is a complex set of interactions among soluble factors and cells that can arise in any tissue in response to traumatic, infectious, post-ischaemic, toxic or autoimmune injury. The process normally leads to recovery from infection and to healing, However, if targeted destruction and assisted repair are not properly phased, inflammation can lead to persistent tissue damage by leukocytes, lymphocytes or collagen. Inflammation may be considered in terms of its checkpoints, where binary or higher-order signals drive each commitment to escalate, go signals trigger stop signals, and molecules responsible for mediating the inflammatory response also suppress it, depending on timing and context. The non-inflammatory state does not arise passively from an absence of inflammatory stimuli; rather, maintenance of health requires the positive actions of specific gene products to suppress reactions to potentially inflammatory stimuli that do not warrant a full response.     

9例大熊猫肝脏和肾脏的器官病理学观察

 为了解发病死亡的大熊猫肝脏、肾脏的器官病理学变化特点,本研究采用组织病理学、组织化学和免疫组织化学等方法,对9例发病死亡的大熊猫肝脏和肾脏的组织病理形态学变化进行了系统观察。同时检测观察HBV和HEV抗原在大熊猫肝脏、肾脏组织内的分布定位。组织病理学观察发现,9只大熊猫的肝脏和肾脏均表现出不同程度的病变。肝脏主要表现为淤血、水肿,严重的有出血变化。肝细胞普遍变性,散在单个性坏死或多发性局灶性坏死,个别出现大片坏死、淋巴细胞等炎性细胞浸润、汇管区胆管增生、肝细胞萎缩、纤维结缔组织增生、含铁血黄素沉着等变化。肾脏主要表现为肾球囊扩张,肾小管上皮细胞出现不同程度的变性坏死,肾小管内出现蛋白管型,间质程度不同的纤维化和程度不同的炎性细胞浸润。免疫组织化学观察结果发现,9只大熊猫HBV和HEV的阳性检出率比较高,但各例肝肾组织内免疫组织化学阳性反应信号的强弱不尽相同。Mallory三色染色结果显示,9只大熊猫的肝脏和肾脏均出现不同程度的纤维组织增生。上述结果表明,大熊猫的肝脏和肾脏普遍存在炎症病变,而且大多都有不同程度的纤维组织增生性病变。这些病变的发生可能与肝炎病毒的感染有一定的关系。     

Non-apoptotic role of BID in inflammation and innate immunity

Innate immunity is a fundamental defence response that depends on evolutionarily conserved pattern recognition receptors for sensing infections or danger signals. Nucleotide-binding and oligomerization domain (NOD) proteins are cytosolic pattern-recognition receptors of paramount importance in the intestine, and their dysregulation is associated with inflammatory bowel disease. They sense peptidoglycans from commensal microorganisms and pathogens and coordinate signalling events that culminate in the induction of inflammation and anti-microbial responses. However, the signalling mechanisms involved in this process are not fully understood. Here, using genome-wide RNA interference, we identify candidate genes that modulate the NOD1 inflammatory response in intestinal epithelial cells. Our results reveal a significant crosstalk between innate immunity and apoptosis and identify BID, a BCL2 family protein, as a critical component of the inflammatory response. Colonocytes depleted of BID or macrophages from Bid(-/-) mice are markedly defective in cytokine production in response to NOD activation. Furthermore, Bid(-/-) mice are unresponsive to local or systemic exposure to NOD agonists or their protective effect in experimental colitis. Mechanistically, BID interacts with NOD1, NOD2 and the IκB kinase (IKK) complex, impacting NF-κB and extracellular signal-regulated kinase (ERK) signalling. Our results define a novel role of BID in inflammation and immunity independent of its apoptotic function, furthering the mounting evidence of evolutionary conservation between the mechanisms of apoptosis and immunity.     

Co-adjuvant effects of retinoic acid and IL-15 induce inflammatory immunity to dietary antigens

Under physiological conditions the gut-associated lymphoid tissues not only prevent the induction of a local inflammatory immune response, but also induce systemic tolerance to fed antigens. A notable exception is coeliac disease, where genetically susceptible individuals expressing human leukocyte antigen (HLA) HLA-DQ2 or HLA-DQ8 molecules develop inflammatory T-cell and antibody responses against dietary gluten, a protein present in wheat. The mechanisms underlying this dysregulated mucosal immune response to a soluble antigen have not been identified. Retinoic acid, a metabolite of vitamin A, has been shown to have a critical role in the induction of intestinal regulatory responses. Here we find in mice that in conjunction with IL-15, a cytokine greatly upregulated in the gut of coeliac disease patients, retinoic acid rapidly activates dendritic cells to induce JNK (also known as MAPK8) phosphorylation and release the proinflammatory cytokines IL-12p70 and IL-23. As a result, in a stressed intestinal environment, retinoic acid acted as an adjuvant that promoted rather than prevented inflammatory cellular and humoral responses to fed antigen. Altogether, these findings reveal an unexpected role for retinoic acid and IL-15 in the abrogation of tolerance to dietary antigens.     

Dendritic cell PAR1-S1P3 signalling couples coagulation and inflammation

Defining critical points of modulation across heterogeneous clinical syndromes may provide insight into new therapeutic approaches. Coagulation initiated by the cytokine-receptor family member known as tissue factor is a hallmark of systemic inflammatory response syndromes in bacterial sepsis and viral haemorrhagic fevers, and anticoagulants can be effective in severe sepsis with disseminated intravascular coagulation. The precise mechanism coupling coagulation and inflammation remains unresolved. Here we show that protease-activated receptor 1 (PAR1) signalling sustains a lethal inflammatory response that can be interrupted by inhibition of either thrombin or PAR1 signalling. The sphingosine 1-phosphate (S1P) axis is a downstream component of PAR1 signalling, and by combining chemical and genetic probes for S1P receptor 3 (S1P3) we show a critical role for dendritic cell PAR1-S1P3 cross-talk in regulating amplification of inflammation in sepsis syndrome. Conversely, dendritic cells sustain escalated systemic coagulation and are the primary hub at which coagulation and inflammation intersect within the lymphatic compartment. Loss of dendritic cell PAR1-S1P3 signalling sequesters dendritic cells and inflammation into draining lymph nodes, and attenuates dissemination of interleukin-1beta to the lungs. Thus, activation of dendritic cells by coagulation in the lymphatics emerges as a previously unknown mechanism that promotes systemic inflammation and lethality in decompensated innate immune responses.     

Neurosphere-derived multipotent precursors promote neuroprotection by an immunomodulatory mechanism

In degenerative disorders of the central nervous system (CNS), transplantation of neural multipotent (stem) precursor cells (NPCs) is aimed at replacing damaged neural cells. Here we show that in CNS inflammation, NPCs are able to promote neuroprotection by maintaining undifferentiated features and exerting unexpected immune-like functions. In a mouse model of chronic CNS inflammation, systemically injected adult syngeneic NPCs use constitutively activated integrins and functional chemokine receptors to selectively enter the inflamed CNS. These undifferentiated cells survive repeated episodes of CNS inflammation by accumulating within perivascular areas where reactive astrocytes, inflamed endothelial cells and encephalitogenic T cells produce neurogenic and gliogenic regulators. In perivascular CNS areas, surviving adult NPCs induce apoptosis of blood-borne CNS-infiltrating encephalitogenic T cells, thus protecting against chronic neural tissue loss as well as disease-related disability. These results indicate that undifferentiated adult NPCs have relevant therapeutic potential in chronic inflammatory CNS disorders because they display immune-like functions that promote long-lasting neuroprotection.     

Histamine regulates T-cell and antibody responses by differential expression of H1 and H2 receptors

Many pathological processes, including those causing allergies and autoimmune diseases, are associated with the presence of specialized subsets of T helper cells (TH1 and TH2) at the site of inflammation. The diversity of TH1 and TH2 function is not predetermined but depends on signals that drive the cells towards either subset. Histamine, released from effector cells (mast cells and basophils) during inflammatory reactions can influence immune response. Here we report that histamine enhances TH1-type responses by triggering the histamine receptor type 1 (H1R), whereas both TH1- and TH2-type responses are negatively regulated by H2R through the activation of different biochemical intracellular signals. In mice, deletion of H1R results in suppression of interferon (IFN)-gamma and dominant secretion of TH2 cytokines (interleukin (IL)-4 and IL-13). Mutant mice lacking H2R showed upregulation of both TH1 and TH2 cytokines. Relevant to T-cell cytokine profiles, mice lacking H1R displayed increased specific antibody response with increased immunoglobulin-epsilon (IgE) and IgG1, IgG2b and IgG3 compared with mice lacking H2R. These findings account for an important regulatory mechanism in the control of inflammatory functions through effector-cell-derived histamine.     

IL-23 promotes tumour incidence and growth

Chronic inflammation has long been associated with increased incidence of malignancy and similarities in the regulatory mechanisms have been suggested for more than a century. Infiltration of innate immune cells, elevated activities of matrix metalloproteases and increased angiogenesis and vasculature density are a few examples of the similarities between chronic and tumour-associated inflammation. Conversely, the elimination of early malignant lesions by immune surveillance, which relies on the cytotoxic activity of tumour-infiltrating T cells or intra-epithelial lymphocytes, is thought to be rate-limiting for the risk to develop cancer. Here we show a molecular connection between the rise in tumour-associated inflammation and a lack of tumour immune surveillance. Expression of the heterodimeric cytokine interleukin (IL)-23, but not of its close relative IL-12, is increased in human tumours. Expression of these cytokines antagonistically regulates local inflammatory responses in the tumour microenvironment and infiltration of intra-epithelial lymphocytes. Whereas IL-12 promotes infiltration of cytotoxic T cells, IL-23 promotes inflammatory responses such as upregulation of the matrix metalloprotease MMP9, and increases angiogenesis but reduces CD8 T-cell infiltration. Genetic deletion or antibody-mediated elimination of IL-23 leads to increased infiltration of cytotoxic T cells into the transformed tissue, rendering a protective effect against chemically induced carcinogenesis. Finally, transplanted tumours are growth-restricted in hosts depleted for IL-23 or in IL-23-receptor-deficient mice. Although many strategies for immune therapy of cancer attempt to stimulate an immune response against solid tumours, infiltration of effector cells into the tumour tissue often appears to be a critical hurdle. We show that IL-23 is an important molecular link between tumour-promoting pro-inflammatory processes and the failure of the adaptive immune surveillance to infiltrate tumours.     

Apoptosis induced by （DIPP-L-Leu）2-L-Lys-OCH3 in K562 cells

Apoptosis as a mechanism of deleting cells from tissues plays an important role in physiological and varieties of pathological situations, especially cancer conditions. In order to search for tumor cells apoptosis inducers, the inhibition effects on K562 cells of N-phosphoryl dipeptide methyl esters were studied by MTT assays, and (DIPP-L-Leu)2-L-Lys-OCH3 was the compound which had the best activity. From the studies of the typical apoptotic morphologic changes, DNA agarose gel electrophoresis, and flow cytometry analysis, it could be concluded that (DIPP-L-Leu)2-L-Lys-OCH3 could induce apoptosis of K562 cells in a dose-dependent manner, and the IC50 was 22.66 μmol/L according to MTT assays.     

Response to self antigen imprints regulatory memory in tissues

Immune homeostasis in tissues is achieved through a delicate balance between pathogenic T-cell responses directed at tissue-specific antigens and the ability of the tissue to inhibit these responses. The mechanisms by which tissues and the immune system communicate to establish and maintain immune homeostasis are currently unknown. Clinical evidence suggests that chronic or repeated exposure to self antigen within tissues leads to an attenuation of pathological autoimmune responses, possibly as a means to mitigate inflammatory damage and preserve function. Many human organ-specific autoimmune diseases are characterized by the initial presentation of the disease being the most severe, with subsequent flares being of lesser severity and duration. In fact, these diseases often spontaneously resolve, despite persistent tissue autoantigen expression. In the practice of antigen-specific immunotherapy, allergens or self antigens are repeatedly injected in the skin, with a diminution of the inflammatory response occurring after each successive exposure. Although these findings indicate that tissues acquire the ability to attenuate autoimmune reactions upon repeated responses to antigens, the mechanism by which this occurs is unknown. Here we show that upon expression of self antigen in a peripheral tissue, thymus-derived regulatory T cells (T(reg) cells) become activated, proliferate and differentiate into more potent suppressors, which mediate resolution of organ-specific autoimmunity in mice. After resolution of the inflammatory response, activated T(reg) cells are maintained in the target tissue and are primed to attenuate subsequent autoimmune reactions when antigen is re-expressed. Thus, T(reg) cells function to confer 'regulatory memory' to the target tissue. These findings provide a framework for understanding how T(reg) cells respond when exposed to self antigen in peripheral tissues and offer mechanistic insight into how tissues regulate autoimmunity.     

山香圆总黄酮对慢性咽炎模型大鼠 NF-κB、IκBα表达的影响

以2.5%氨水喷咽部建立大鼠慢性咽炎模型,用HE染色法观察咽部病理形态学改变,用ELISA法检测血清炎症因子TNF-α、IL-1β、IL-6,用RT-qPCR测定咽部组织NF-κBp65mRNA的表达,用Western blot检测咽部组织NF-κBp65和IκBα蛋白的表达,探讨山香圆总黄酮对慢性咽炎模型大鼠 NF-κB、IκBα表达的影响.结果显示:山香圆总黄酮能明显改善模型大鼠咽部病理形态学; 与模型组比较,山香圆总黄酮各组能不同程度地下调TNF-α、IL-1β、IL-6和NF-κBp65的表达并上调IκBα的表达,其中高剂量组最显著.这表明山香圆总黄酮能通过抑制NF-κB的表达和IκBα的解离下调炎症因子TNF-α、IL-1β、IL-6的表达,从而减轻炎症,发挥抗慢性咽炎作用.     

低阻经络研究Ⅳ. 对经络生理学功能的推测

在《低阻经络研究Ⅲ》“经络是疏松结缔组织里间液较丰富的带区”推断的基础上,根据已确立的生理学事实,进一步推测：经络是经络信息载体物质扩散的低阻通道;经络信息载体物质是组胺;以及经络生物信息放大器是肥大细胞。在此基础上,又提出关于经络功能的“疏松结缔组织-血管-神经机能一体化”假说。最后说明,疏松结缔组织网络如何具有中国医学所注意到的经络系统的各种机能,包括在正常生理条件下的功能,在病理条件下的效应,针灸引起的感觉和反应沿经络的传递,以及用针灸体表经络来治疗有关内脏的疾患,等等。     

Semaphorin 7A initiates T-cell-mediated inflammatory responses through alpha1beta1 integrin

Semaphorins are axon guidance factors that assist growing axons in finding appropriate targets and forming synapses. Emerging evidence suggests that semaphorins are involved not only in embryonic development but also in immune responses. Semaphorin 7A (Sema7A; also known as CD108), which is a glycosylphosphatidylinositol-anchored semaphorin, promotes axon outgrowth through beta1-integrin receptors and contributes to the formation of the lateral olfactory tract. Although Sema7A has been shown to stimulate human monocytes, its function as a negative regulator of T-cell responses has also been reported. Thus, the precise function of Sema7A in the immune system remains unclear. Here we show that Sema7A, which is expressed on activated T cells, stimulates cytokine production in monocytes and macrophages through alpha1beta1 integrin (also known as very late antigen-1) as a component of the immunological synapse, and is critical for the effector phase of the inflammatory immune response. Sema7A-deficient (Sema7a-/-) mice are defective in cell-mediated immune responses such as contact hypersensitivity and experimental autoimmune encephalomyelitis. Although antigen-specific and cytokine-producing effector T cells can develop and migrate into antigen-challenged sites in Sema7a-/- mice, Sema7a-/- T cells fail to induce contact hypersensitivity even when directly injected into the antigen-challenged sites. Thus, the interaction between Sema7A and alpha1beta1 integrin is crucial at the site of inflammation. These findings not only identify a function of Sema7A as an effector molecule in T-cell-mediated inflammation, but also reveal a mechanism of integrin-mediated immune regulation.     

Two calcium-binding proteins in infiltrate macrophages of rheumatoid arthritis

The aetiology and cellular mechanism of chronic inflammatory processes are poorly understood. Macrophages act prominently in the inflammatory response and we report here that they express two calcium-binding proteins. The expression of these proteins, referred to as MRP-8 and MRP-14, is specific for cells of myeloid origin, namely granulocytes, monocytes and macrophages, and is observed in blood granulocytes and monocytes but not in normal tissue macrophages. In acutely inflamed tissues, macrophages can express MRP-14 but not MRP-8, and in chronic inflammations, such as primary chronic polyarthritis, infiltrate macrophages express both MRP-8 and MRP-14. Characterization of MRP-8 and MRP-14 could therefore be useful to the understanding of cellular processes induced in chronic inflammation.