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Crosstalk of Signaling Mechanisms Involved in Host Defense and Symbiosis Against Microorganisms in Rice
Rice is one of the most important food crops, feeding about half population in the world. Rice pathogens cause enormous damage to rice production worldwide. In plant immunity research, considerable progress has recently been made in our understanding of the molecular mechanisms underlying microbe-associated molecular pattern (MAMP)-triggered immunity. Using genome sequencing and molecular techniques, a number of new MAMPs and their receptors have been identified in the past two decades. Notably, the mechanisms for chitin perception via the lysine motif (LysM) domain-containing receptor OsCERK1, as well as the mechanisms for bacterial MAMP (e.g. flg22, elf18) perception via the leucine-rich repeat (LRR) domain-containing receptors FLS2 and EFR, have been clarified in rice and Arabidopsis, respectively. In chitin signaling in rice, two direct substrates of OsCERK1, Rac/ROP GTPase guanine nucleotide exchange factor OsRacGEF1 and receptor-like cytoplasmic kinase OsRLCK185, have been identified as components of the OsCERK1 complex and are rapidly phosphorylated by OsCERK1 in response to chitin. Interestingly, OsCERK1 also participates in symbiosis with arbuscular mycorrhizal fungi (AMF) in rice and plays a role in the recognition of short-chitin molecules (CO4/5), which are symbiotic signatures included in AMF germinated spore exudates and induced by synthetic strigolactone. Thus, OsCERK1 contributes to both immunity and symbiotic responses. In this review, we describe recent studies on pathways involved in rice immunity and symbiotic signaling triggered by interactions with microorganisms. In addition, we describe recent advances in genetic engineering by using plant immune receptors and symbiotic microorganisms to enhance disease resistance of rice.
Anti-arthritic Effect and Underlying Mechanism of Ginsenoside Metabolite Compound K
Ginsenoside metabolite compound K (CK) is a degradation product of panaxadiol (Rb1, Rb2, Rc) in the intestine by bacteria and is the major form of ginsenoside absorbed in the body. Recently, the anti-arthritic effect of CK has been confirmed in adjuvant-induced arthritis rats and collagen- induced arthritis mice and also in in vitro experiments. CK can regulate the function of cells which are involved in rheumatoid arthritis including immune cells, endothelial cells and fibroblast synoviocytes resulting in the anti-arthritic effect. The mechanisms of these effects may be mediated by different signaling pathways including glucocorticoid receptors, Toll-like receptors, ion channels, NF-κB and MAPKs.
Plant-based Anti-inflammatory Agents: Progress From Africa and China
Chronic inflammation has become an integral part of man’s suffering. Although the etiology of inflammatory diseases is still unclear, evidence shows that it is multifactorial involving several proinflammatory cytokines, chemokines, free radicals, and other regulators of the immune system. Environmental, genetic and epigenetic factors have also been shown to play key roles in the pathogenesis of inflammatory diseases. Conventional drugs such as non-steroidal anti-inflammatory drugs (NSAIDs), disease modifying anti-rheumatic drugs (DMARDs), glucocorticoids and biological agents are used to manage the symptoms but are unable to deal with the underlying causes. Also, they have many serious adverse reactions. To deal with this, many alternatives have been suggested and among them, plant-based secondary metabolites (SM) stands out. The aim of this review therefore, is to make an inventory of secondary metabolites of plants from Africa and China that are used to treat inflammatory diseases focusing on rheumatoid arthritis (RA), asthma and systemic lupus erythematosus (SLE). Also, the possible mechanisms of these SM will be highlighted. Finally, active compounds isolated from these plants that regulate specific inflammatory mediators will be summarized.
The Immunomodulatory Effects of Physical Activity
Background: An individual's level of physical activity is one of a set of lifestyle and behavioral factors that can affect immune function and health. Methods: The purpose of this review is to summarize the current knowledge in this research field and to review the recent developments in exercise immunology. Results: Most studies show that regular exercise training increases immune competence and reduces the risk of infection compared to a sedentary lifestyle. In contrast, acute prolonged bouts of exercise and periods of intensified training are followed by a temporary increase in the risk of infection. These observations have been attributed to differential exercise-induced changes of a series of humoral and cellular immune system parameters. Furthermore, regular exercise training is a countermeasure against a persistent systemic inflammatory state which is a typical feature of cardiovascular and metabolic diseases is by lowering levels of pro-inflammatory cytokines. It is supposed that these effects are mediated by a modification of metabolic signals and innate immune regulation, the release of anti-inflammatory cytokines from muscle, the release of stress hormones, and a process known as browning of adipose tissue. Conclusion: The effects of physical activity on the immune system strongly depend on the mode and intensity of exercise or training. Thereby, considerable knowledge has accumulated concerning the significance of exercise as an important lifestyle factor for prevention and therapy of major chronic diseases.
Logical Analysis of Regulation of Interleukin-12 Expression Pathway Regulation During HCV Infection
Hepatitis C virus (HCV) triggers coordinated innate and adaptive response in host cell. HCV genome and proteins of the replicating virus are recognized as non-self-antigens by host cell to activate Toll Like Receptors (TLRs). Activated TLRs ultimately express cytokines, which can clear virus either by activating interferon (IFN), protein kinase C (PKC) and RNA Lase system or through activation of cytotoxic T-lymphocytes. Interleukin-12 (IL-12) is a potent antiviral cytokine, capable of clearing HCV by bridging both innate and adaptive antiviral immune response. Activation of TLR-4 on macrophages surface induces expression of IL-12 via NF-κB and AP-1 transcriptional pathway. After expression, IL- 12 releases IFN-γ, which activates anti-HCV cytotoxic lymphocytes. Conversely, in chronic HCV infection downregulation of IL-12 has been reported instead of by number of studies. Keeping in view of the above mentioned facts, this study was designed to evaluate HCV-core mediated down-regulation of IL-12 transcriptional pathway by employing a logical modeling approach based on the Ren´e Thomas formalism. The logical parameters of entities were estimated by using SMBioNet. The Logical model represents all possible dynamics of protein expression involved during course of HCV pathology. Results demonstrated that at chronic stage of infection, though TLR-4 was constantly active but yet it failed to express the NF-κB, AP-1, IL-12 and IFN- . This mechanism was indicative of incorporation of core mediated changes in IL-12 regulatory pathway. Moreover, results also indicate that HCV adopts different trajectories to accomplish the persistence of chronic phase of infection. It also implicated that human immune system tries to clear HCV but core is capable of inducing system oscillations to evade the immunity.
Impact of Macrophages in Atherosclerosis
Atherosclerosis is driven by inflammation, with a strong involvement of innate immunity, and involves an expansion of the arterial intima, a normally small area composed of several cell types including smooth muscle cells, lipids, monocytes, macrophages, dendritic cells, and extracellular matrix. Macrophages derived from recruited monocytes are predominant innate immune cells that play crucial roles in the formation of atherosclerotic lesions. Human atherosclerotic plaques have shown that macrophage subsets within a plaque might be more useful for explaining plaque phenotype than just simply giving the total number of macrophages. Therefore, recognizing the roles of macrophage subsets in atherosclerotic plaque formation, progression, and regression would be most helpful for identification of novel strategies to stabilize, or attenuate atherosclerotic lesions. This review discusses the impact of macrophage subsets and their roles in atherosclerosis.
The Structure-Function Relationships of Complement Receptor Type 2 (CR2; CD21)
Human complement receptor type 2 (CR2; CD21) is a surface-associated glycoprotein which binds to a variety of endogenous ligands, including the complement component C3 fragments iC3b, C3dg and C3d, the low-affinity IgE receptor CD23, and the type I cytokine, interferon-alpha. CR2 links the innate complement-mediated immune response to pathogens and foreign antigens with the adaptive immune response by binding to C3d that is covalently attached to targets, and which results in a cell signalling phenomenon that lowers the threshold for B cell activation. Variations or deletions of the CR2 gene in humans, or the Cr2 gene in mice associate with a variety of autoimmune and inflammatory conditions. A number of infectious agents including Epstein-Barr virus (EBV), Human Immunodeficiency Virus (HIV) and prions also bind to CR2 either directly or indirectly by means of C3d-targeted immune complexes. </p><p> In this review we discuss the interactions that CR2 undertakes with its best characterized ligands C3d, CD23 and the EBV gp350/220 envelope protein. To date only a single physiologically relevant complex of CR2 with one of its ligands, C3d, has been elucidated. By contrast, the interactions with CD23 and EBV gp350/220, while being important from physiologic and disease-associated standpoints, respectively, are only incompletely understood. A detailed knowledge of the structure-function relationships that CR2 undergoes with its ligands is necessary to understand the implications of using recombinant CR2 in therapeutic or imaging agents, or alternatively targeting CR2 to down-regulate the antibody mediated immune response in cases of autoimmunity. </p><p>
Interrelationship Between Periapical Lesion and Systemic Metabolic Disorders
Background: Periapical periodontitis, also known as periapical lesion, is a common dental disease, along with periodontitis (gum disease). Periapical periodontitis is a chronic inflammatory disease, caused by endodontic infection, and its development is regulated by the host immune/inflammatory response. Metabolic disorders, which are largely dependent on life style such as eating habits, have been interpreted as a “metabolically-triggered” low-grade systemic inflammation and may interact with periapical periodontitis by triggering immune modulation. The host immune system is therefore considered the common fundamental mechanism of both disease conditions. Method: We have reviewed >200 articles to discuss the interrelationship between periapical lesions and metabolic disorders including type 2 diabetes mellitus, hypertension, and non-alcoholic fatty liver diseases (NAFLD), and their common pathological background in immunology/osteoimmunology and cytokine biology. Results: An elevated inflammatory state caused by metabolic disorders can impact the clinical outcome of periapical lesions and interfere with wound healing after endodontic treatment. Although additional well-designed clinical studies are needed, periapical lesions appear to affect insulin sensitivity and exacerbate non-alcoholic steatohepatitis. Conclusion: Immune regulatory cytokines produced by various cell types, including immune cells and adipose tissue, play an important role in this interrelationship.
Emerging Immunotargets and Immunotherapies in Prostate Cancer
Innate and adaptive immunity are both involved in prostate cancer (PCa) carcinogenesis and progression. On this scenario, several immunotherapeutic approaches have been proposed and are presently under extensive investigation in PCa patients. Among emerging immune targets, immune checkpoint inhibitors such as anti-cytotoxic T-lymphocyteassociated protein 4 (CTLA-4), anti-Programmed death-1 (PD-1) and anti-Programmed death-ligand-1 (PD-L1) agents seem to represent the most promising candidate for these patients, together with oncolytic viruses and vaccines, used alone or in combined strategies. In this review, we focused on emerging immunotherapeutic approaches in patients with PCa, showing the rational for their association with current standard therapies including anti-androgen agents, chemo- or radiation therapy.
Lithium Distinctly Modulates the Secretion of Pro- and Anti- Inflammatory Interleukins in Co-Cultures of Neurons and Glial Cells at Therapeutic and Sub-Therapeutic Concentrations
Lithium is associated with various effects on immune functions, some of which are still poorly understood. The roles of many cytokines have been characterized in a variety of neurodevelopmental processes including neurogenesis, neuronal and glial cell migration, proliferation, differentiation, synaptic maturation and synaptic pruning. This work aims to evaluate the effects of different doses of lithium (0.02; 0.2 and 2mM) on the secretion of cytokines in co-cultures of cortical and hippocampal neurons with glial cells. Our results indicate that chronic treatment with lithium chloride at subtherapeutic concentrations are able to modify the secretion of pro- and anti-inflammatory interleukins in co-cultures of cortical and hippocampal neurons with glial cells.
Structure and Expression of Different Serum Amyloid A (SAA) Variants and their Concentration-Dependent Functions During Host Insults
Serum amyloid A (SAA) is, like C-reactive protein (CRP), an acute phase protein and can be used as a diagnostic, prognostic or therapy follow-up marker for many diseases. Increases in serum levels of SAA are triggered by physical insults to the host, including infection, trauma, inflammatory reactions and cancer. The order of magnitude of increase in SAA levels varies considerably, from a 10- to 100- fold during limited inflammatory events to a 1000-fold increase during severe bacterial infections and acute exacerbations of chronic inflammatory diseases. This broad response range is reflected by SAA gene duplications resulting in a cluster encoding several SAA variants and by multiple biological functions of SAA. SAA variants are single-domain proteins with simple structures and few post-translational modifications. SAA1 and SAA2 are inducible by inflammatory cytokines, whereas SAA4 is constitutively produced. We review here the regulated expression of SAA in normal and transformed cells and compare its serum levels in various disease states. At low concentrations (10-100 ng/ml), early in an inflammatory response, SAA induces chemokines or matrix degrading enzymes via Toll-like receptors and functions as an activator and chemoattractant through a G protein-coupled receptor. When an infectious or inflammatory stimulus persists, the liver continues to produce more SAA (≥ 1000 ng/ml) to become an antimicrobial agent by functioning as a direct opsonin of bacteria or by interference with virus infection of host cells. Thus, SAA regulates innate and adaptive immunity and this information may help to design better drugs to treat specific diseases.
Dendritic Cells in Colorectal Cancer and a Potential for their Use in Therapeutic Approaches
Multiple pathogenic mechanisms contribute to the development of colorectal cancer. This tumor is characterized by high chemoresistance and low immunogenicity due to the effective mechanisms of immunosuppression. Dendritic cells (DCs) play a key role in recognition of tumor antigens and induction of T-cell-primed anticancer response. However, in cancer microenvironment, the function of tumor-infiltrating DCs becomes impaired and switched from the immunostimulation to the immunosuppression. Colorectal cancer cells express anti-inflammatory cytokines such as IL-10 and TGF-β that could affect DC phenotype and support tumor escape from the immune surveillance. As a result, tumor-associated DCs display numerous defects in antigen-presenting capacity and have an altered pattern of expression of immune costimulatory molecules towards the immunoregulatory phenotype. Indeed, understanding of mechanisms, such as how tumor could impair activity of DCs, would help in the development of new DC-based vaccines against colorectal cancer.
Oncotarget Strategies For Herpes Simplex Virus-1
The high level of manipulability of viral genome has set up HSV-1 to be an ideal viral vector for oncolytic virotherapy. In the past two decades, several oncolytic HSV-1 viruses have been successfully developed and assessed in animal studies. Accumulated evidences show that oncolytic HSV- 1 can efficiently infect many tumor cells and augment anti-tumor effect by induction of systemic innate and adaptive immune responses. Inspiring results have been accomplished in several phase I clinical trials for glioma, head and neck squeous cells carcinoma and Melanoma using oncolytic HSV- 1 viruses. More recently, oncovey, one of oncolytic HSV-1 viruses has been approved by FDA for the comprehensive evolution of its anti-tumor effects in phase III clinical trials. These promising studies encourage more efforts to be devoted to craft the new generation of oncolytic HSV-1. Herein, we will review and summarize the basic strategies to construct oncolytic HSV-1 viruses and their applications in cancer therapy.
Lentiviral Delivery of Proteins for Genome Engineering
Viruses have evolved to traverse cellular barriers and travel to the nucleus by mechanisms that involve active transport through the cytoplasm and viral quirks to resist cellular restriction factors and innate immune responses. Virus-derived vector systems exploit the capacity of viruses to ferry genetic information into cells, and now - more than three decades after the discovery of HIV - lentiviral vectors based on HIV-1 have become instrumental in biomedical research and gene therapies that require genomic insertion of transgenes. By now, the efficacy of lentiviral gene delivery to stem cells, cells of the immune system including T cells, hepatic cells, and many other therapeutically relevant cell types is well established. Along with nucleic acids, HIV-1 virions carry the enzymatic tools that are essential for early steps of infection. Such capacity to package enzymes, even proteins of nonviral origin, has unveiled new ways of exploiting cellular intrusion of HIV-1. Based on early findings demonstrating the packaging of heterologous proteins into virus particles as part of the Gag and GagPol polypeptides, we have established lentiviral protein transduction for delivery of DNA transposases and designer nucleases. This strategy for delivering genome-engineering proteins facilitates high enzymatic activity within a short time frame and may potentially improve the safety of genome editing. Exploiting the full potential of lentiviral vectors, incorporation of foreign protein can be combined with the delivery of DNA transposons or a donor sequence for homology-directed repair in so-called ‘all-in-one’ lentiviral vectors. Here, we briefly describe intracellular restrictions that may affect lentiviral gene and protein delivery and review the current status of lentiviral particles as carriers of tool kits for genome engineering.
Allosteric Modulation of Nicotinic Acetylcholine Receptors: The Concept and Therapeutic Trends
Expressing functional nicotinic acetylcholine receptors (nAChRs) may be beneficial to central neurons and neuronal networks because activation of nAChRs enhances neuronal resistance to injury, improves attention, cognitive performance, and produces robust anti-inflammatory and analgesic effects in mammals. Although exogenous orthosteric nAChR ligands present valuable tools in treatment of age- and trauma-related neurological deficits, therapeutic approaches that could amplify the brain’s innate ability to maintain cholinergic homeostasis and resist injury may serve as intriguing and promising alternatives and have not been fully explored. One of these novel approaches utilizes positive allosteric modulators (PAMs) of nAChRs. Because of the ubiquitous expression of nAChRs in neuronal, glial and immune tissues, highly selective PAMs could amplify multiple endogenous neuroprotective, pro-cognitive, anti-inflammatory and anti-nociceptive cholinergic pathways to offset cholinergic hypofunction and generate therapeutic efficacy by targeting only a single player: i.e., nAChRs activated by endogenous cholinergic tone. In this article, I review the concept of allosteric modulation and current trends in therapeutic applications of nicotinic PAMs.
An Overview of Emerging Immunotargets of Genitourinary Tumors
Emerging immunotherapies targeting immune checkpoints and tumor associated antigens are leading to important clinical advances and providing a new weapon in patients with prostate (PCa) and bladder cancer (BC) and, in particular, with renal cell carcinoma (RCC). The possibility to integrate these agents in the current therapeutic scenario or genitourinary tumors, both in sequential or combined approaches, relies on a more profound comprehension of the protumorigenic activity of the immune system and of the mechanisms of cancer-related immunosuppression. In this regards, neutrophils, T and B lymphocytes and tumor-associated macrophages (TAMs) are implicated in the pathogenesis, progression and development of drug resistance in genitourinary tumors. This review is an overview on the recent insights concerning the role of immune cells in this context.
Therapeutic Targets for Management of Periodontitis and Diabetes
The increasing incidence of diabetes mellitus (DM) and chronic periodontitis (CP) worldwide imposes a rethinking of individualized therapy for patients with both conditions. Central to bidirectional links between DM and CP is deregulated systemic inflammation and dysfunctional immune responses to altered-self and non-self. Control of blood glucose levels and metabolic imbalances associated with hyperglycemia in DM, and disruption of pathogenic subgingival biofilms in CP are currently the main therapeutic approaches for these conditions. Mounting evidence suggests the need to integrate immune modulatory therapeutics in treatment regimens that address the unresolved inflammation associated with DM and CP. The current review discusses the pathogenesis of DM and CP with emphasis on deregulated inflammation, current therapeutic approaches and the novel pro-resolution lipid mediators derived from -3 polyunsaturated fatty acids.
Thermostable Subunit Vaccines for Pulmonary Delivery: How Close Are We?
In the past century, vaccines have contributed to a significant improvement in global public health by preventing a number of infectious diseases. Despite this, the vaccine field is still facing challenges related to incomplete vaccine coverage and persistent difficult vaccine targets, such as influenza, tuberculosis, and Ebola, for which no good universal vaccines exist. At least two pharmaceutical improvements are expected to help filling this gap: i) The development of thermostable vaccine dosage forms, and ii) the full exploitation of the adjuvant technology for subunit vaccines to potentiate strong immune responses. This review highlights the status and recent advances in formulation and pulmonary delivery of thermostable human subunit vaccines. Such vaccines are very appealing from compliance, distribution and immunological point of view: Being non-invasive, inhalable vaccines are self-administrable, can be distributed independently of functioning freezers and refrigerators, and can be designed to induce mucosal and/or cell-mediated immunity, which is attractive for a number of diseases requiring stimulation of local mucosal immunity for protection. However, the design and delivery of thermostable dry powder-based vaccines represents a technological challenge: It calls for careful formulation and dosage form design, combined with cheap and efficient delivery devices, which must be engineered via a thorough understanding of the physiological barrier and the requirements for induction of mucosal immunity. Here, I review state of the art and perspectives in formulation design and processing methods for powder-based subunit vaccines intended for pulmonary administration, and present dry powder inhaler technologies suitable for translating these vaccines into clinical trials.
Emerging Immunotargets in Metastatic Renal Cell Carcinoma
Renal cell carcinoma (RCC) is one of the most immunoresponsive human cancers. High-dose IL-2 and Interferon-α were once the principle therapies for metastatic RCC, however they had harsh-tolerance profiles and limited response rates. In the last decade, targeted therapies have supplanted cytokine therapy due to higher response rates and more favorable toxicity profiles. Emerging immunotherapies targeting the PD-1 receptor and PD-L1 ligand have shown promising results. Likewise, other novel targeted immunotherapies are currently under evaluation. The safety profiles and response rates of new generation immunotherapies are encouraging and justify the progression of clinical trials. However, longer follow-up data are needed to confirm these promising results. In addition, it is still unclear if an optimal sequence or combinations of new immunotherapies paired with current targeted therapies will emerge.
An Interplay between Obesity and Inflammation in Gestational Diabetes Mellitus
Gestational diabetes mellitus (GDM) is traditionally defined as hyperglycemia first detected in pregnancy. The risk of GDM is much higher among obese women than in their lean counterparts. An excess of adipose tissue leads to immune and inflammatory responses of both white adipose tissue and the placenta, contributing to systemic inflammation. Although the significance of both obesity and inflammation is relatively well characterized in GDM, the molecular mechanisms involved are not fully defined and require further study. In recent years huge progress has been made in identifying the intracellular signaling pathways involved in the pathophysiology of GDM. However, currently available data regarding inflammation and obesity in women with GDM are still conflicting or incomplete. We discuss selected aspects of the problem and propose future directions for research in the hope of achieving a better understanding of the disease. In particular, this review highlights recent studies exploring molecular alterations related to insulin resistance, inflammation of the adipose tissue and the placenta, lipotoxicity or endotoxemia.
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