Properdin Is a Modulator of Tumour Immunity in a Syngeneic Mouse Melanoma Model.

Background and Objectives: Tumours are often low immunogenic. The role of complement, an innate immune defence system, in tumour control has begun to be elucidated, but findings are conflicting. A role for properdin, an amplifier of complement activation, in tumour control has recently been implicated. Materials and Methods: Properdin-deficient and congenic wildtype mice were injected subcutaneously with B16F10 melanoma cells. Tumour mass and chemokine profile were assessed. The frequencies of CD45+CD11b+ Gr-1+ cells were determined from tumours and spleens, and CD206+ F4/80+ cells were evaluated in spleens. Sera were analysed for C5a, sC5b-9, and CCL2. Results: Whilst there was no difference in tumour growth at study endpoint, properdin-deficient mice had significantly fewer myeloid-derived suppressor cells (MDSCs) in their tumours and spleens. Splenic M2 type macrophages and serum levels of C5a, sC5b-9, and CCL2 were decreased in properdin-deficient compared to wildtype mice. Conclusions: The presence of intact complement amplification sustains an environment that lessens potential anti-tumour responses.

Complement Properdin Determines Disease Activity in MRL/lpr Mice.

Background and objects: In systemic lupus erythematosus, circulating immune complexes activate complement and, when trapped in renal capillaries, cause glomerulonephritis. Mouse models have been used in the preclinical assessment of targeting complement activation pathways to manage chronic inflammation in lupus. Properdin is the only known positive regulator of complement activation, but its role in the severity of lupus nephritis has not been studied yet. Materials and Methods: Fully characterized properdin-deficient mice were crossed with lupus prone MRL/lpr mice on C57Bl/6 background. Results: Compared to MRL/lpr properdin wildtype mice, MRL/lpr properdin-deficient mice had significantly lower anti-DNA antibody titres, TNFα and BAFF levels in serum. The qualitative glomerulonephritic score was less severe and there was significantly less serum creatinine in MRL/lpr properdin-deficient mice compared to MRL/lpr properdin wildtype littermate mice. Conclusion: Properdin plays a significant role in the severity of lupus overall and specifically in the extent of glomerulonephritis observed in MRL/lpr mice. Because MRL/lpr properdin-deficient mice had lower levels of anti-DNA antibodies, inflammatory mediators and markers of renal impairment, the study implies that properdin could constitute a novel therapy target in lupus disease.

The Value of Targeting Complement Components in Asthma.

Asthma is an important respiratory illness. Though pharmacological and biological treatment is well established and is staged according to endotypes and their responses to treatment, novel avenues are being explored. Our focus is complement. In this viewpoint, we evaluate the approach to target complement in this complex hypersensitivity reaction that develops chronicity and has a personal-as well as a societal-cost.

Complement Properdin Regulates the Metabolo-Inflammatory Response to a High Fat Diet.

Background and objectives: Overnutrition leads to a metabolic and inflammatory response that includes the activation of Complement. Properdin is the only amplifier of complement activation and increases the provision of complement activation products. Its absence has previously been shown to lead to increased obesity in mice on a high fat diet. The aim of this study was to determine ways in which properdin contributes to a less pronounced obese phenotype. Materials and Methods: Wild type (WT) and properdin deficient mice (KO) were fed a high-fat diet (HFD) for up to 12 weeks. Results: There was a significant increase in liver triglyceride content in the KO HFD group compared to WT on HFD. WT developed steatosis. KO had an additional inflammatory component (steatohepatitis). Analysis of AKT signalling by phosphorylation array supported a decrease in insulin sensitivity which was greater for KO than WT in liver and kidney. There was a significant decrease of C5L2 in the fat membranes of the KO HFD group compared to the WT HFD group. Circulating microparticles in KO HFD group showed lower presence of C5L2. Expression of the fatty acid transporter CD36 in adipose tissue was increased in KO on HFD and was also significantly increased in plasma of KO HFD mice compared to WT on HFD. CD36 was elevated on microparticles from KO on HFD. Ultrastructural changes consistent with obesity-associated glomerulopathy were observed for both HFD fed genotypes, but tubular strain was greater in KO. Conclusion: Our work demonstrates that complement properdin is a dominant factor in limiting the severity of obesity-associated conditions that impact on liver and kidney. The two receptors, C5L2 and CD36, are downstream of the activity exerted by properdin.

Experimentally-induced anti-myeloperoxidase vasculitis does not require properdin, MASP-2 or bone marrow-derived C5.

Anti-neutrophil cytoplasmic antibody vasculitis is a systemic autoimmune disease with glomerulonephritis and pulmonary haemorrhage as major clinical manifestations. The name reflects the presence of autoantibodies to myeloperoxidase and proteinase-3, which bind to both neutrophils and monocytes. Evidence of the pathogenicity of these autoantibodies is provided by the observation that injection of anti-myeloperoxidase antibodies into mice causes a pauci-immune focal segmental necrotizing glomerulonephritis which is histologically similar to the changes seen on renal biopsy in patients. Previous studies in this model have implicated the alternative pathway of complement activation and the anaphylatoxin C5a. Despite this progress, the factors that initiate complement activation have not been defined. In addition, the relative importance of bone marrow-derived and circulating C5 is not known. This is of interest given the recently identified roles for complement within leukocytes. We induced anti-myeloperoxidase vasculitis in mice and confirmed a role for complement activation by demonstrating protection in C3-deficient mice. We showed that neither MASP-2- nor properdin-deficient mice were protected, suggesting that alternative pathway activation does not require properdin or the lectin pathway. We induced disease in bone marrow chimaeric mice and found that circulating and not bone marrow-derived C5 was required for disease. We have therefore excluded properdin and the lectin pathway as initiators of complement activation and this means that future work should be directed at other potential factors within diseased tissue. In addition, in view of our finding that circulating and not bone marrow-derived C5 mediates disease, therapies that decrease hepatic C5 secretion may be considered as an alternative to those that target C5 and C5a. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Properdin provides protection from Citrobacter rodentium-induced intestinal inflammation in a C5a/IL-6-dependent manner.

Citrobacter rodentium is an attaching and effacing mouse pathogen that models enteropathogenic and enterohemorrhagic Escherichia coli in humans. The complement system is an important innate defense mechanism; however, only scant information is available about the role of complement proteins during enteric infections. In this study, we examined the impact of the lack of properdin, a positive regulator of complement, in C. rodentium-induced colitis. Following infection, properdin knockout (P(KO)) mice had increased diarrhea and exacerbated inflammation combined with defective epithelial cell-derived IL-6 and greater numbers of colonizing bacteria. The defect in the mucosal response was reversed by administering exogenous properdin to P(KO) mice. Then, using in vitro and in vivo approaches, we show that the mechanism behind the exacerbated inflammation of P(KO) mice is due to a failure to increase local C5a levels. We show that C5a directly stimulates IL-6 production from colonic epithelial cells and that inhibiting C5a in infected wild-type mice resulted in defective epithelial IL-6 production and exacerbated inflammation. These outcomes position properdin early in the response to an infectious challenge in the colon, leading to complement activation and C5a, which in turn provides protection through IL-6 expression by the epithelium. Our results unveil a previously unappreciated mechanism of intestinal homeostasis involving complement, C5a, and IL-6 during bacteria-triggered epithelial injury.

Mechanisms of Stress-Mediated Modulation of Upper and Lower Respiratory Tract Infections.

Stress is an external factor known to be a potent exacerbator of respiratory infections. Most explanations of how stress affects susceptibility to airway infections focus on the immune system. However, evidence is increasing that respiratory pathogens are equally responsive to the hormonal output of stress. This chapter considers the bacterial and mucosal determinants of respiratory tract infections and their interrelationship during stressful conditions.

Antibody directs properdin-dependent activation of the complement alternative pathway in a mouse model of abdominal aortic aneurysm.

Abdominal aortic aneurysm (AAA) is a complex inflammatory vascular disease. There are currently limited treatment options for AAA when surgery is inapplicable. Therefore, insights into molecular mechanisms underlying AAA pathogenesis may reveal therapeutic targets that could be manipulated pharmacologically or biologically to halt disease progression. Using an elastase-induced AAA mouse model, we previously established that the complement alternative pathway (AP) plays a critical role in the development of AAA. However, the mechanism by which complement AP is initiated remains undefined. The complement protein properdin, traditionally viewed as a positive regulator of the AP, may also initiate complement activation by binding directly to target surfaces. In this study, we sought to determine whether properdin serves as a focal point for the initiation of the AP complement activation in AAA. Using a properdin loss of function mutation in mice and a mutant form of the complement factor B protein that produces a stable, properdin-free AP C3 convertase, we show that properdin is required for the development of elastase-induced AAA in its primary role as a convertase stabilizer. Unexpectedly, we find that, in AAA, natural IgG antibodies direct AP-mediated complement activation. The absence of IgG abrogates C3 deposition in elastase-perfused aortic wall and protects animals from AAA development. We also determine that blockade of properdin activity prevents aneurysm formation. These results indicate that an innate immune response to self-antigens activates the complement system and initiates the inflammatory cascade in AAA. Moreover, the study suggests that properdin-targeting strategies may halt aneurysmal growth.

The lectin pathway of complement activation is a critical component of the innate immune response to pneumococcal infection.

The complement system plays a key role in host defense against pneumococcal infection. Three different pathways, the classical, alternative and lectin pathways, mediate complement activation. While there is limited information available on the roles of the classical and the alternative activation pathways of complement in fighting streptococcal infection, little is known about the role of the lectin pathway, mainly due to the lack of appropriate experimental models of lectin pathway deficiency. We have recently established a mouse strain deficient of the lectin pathway effector enzyme mannan-binding lectin associated serine protease-2 (MASP-2) and shown that this mouse strain is unable to form the lectin pathway specific C3 and C5 convertases. Here we report that MASP-2 deficient mice (which can still activate complement via the classical pathway and the alternative pathway) are highly susceptible to pneumococcal infection and fail to opsonize Streptococcus pneumoniae in the none-immune host. This defect in complement opsonisation severely compromises pathogen clearance in the lectin pathway deficient host. Using sera from mice and humans with defined complement deficiencies, we demonstrate that mouse ficolin A, human L-ficolin, and collectin 11 in both species, but not mannan-binding lectin (MBL), are the pattern recognition molecules that drive lectin pathway activation on the surface of S. pneumoniae. We further show that pneumococcal opsonisation via the lectin pathway can proceed in the absence of C4. This study corroborates the essential function of MASP-2 in the lectin pathway and highlights the importance of MBL-independent lectin pathway activation in the host defense against pneumococci.

Targeting of mannan-binding lectin-associated serine protease-2 confers protection from myocardial and gastrointestinal ischemia/reperfusion injury.

Complement research experienced a renaissance with the discovery of a third activation route, the lectin pathway. We developed a unique model of total lectin pathway deficiency, a mouse strain lacking mannan-binding lectin-associated serine protease-2 (MASP-2), and analyzed the role of MASP-2 in two models of postischemic reperfusion injury (IRI). In a model of transient myocardial IRI, MASP-2-deficient mice had significantly smaller infarct volumes than their wild-type littermates. Mice deficient in the downstream complement component C4 were not protected, suggesting the existence of a previously undescribed lectin pathway-dependent C4-bypass. Lectin pathway-mediated activation of C3 in the absence of C4 was demonstrated in vitro and shown to require MASP-2, C2, and MASP-1/3. MASP-2 deficiency also protects mice from gastrointestinal IRI, as do mAb-based inhibitors of MASP-2. The therapeutic effects of MASP-2 inhibition in this experimental model suggest the utility of anti-MASP-2 antibody therapy in reperfusion injury and other lectin pathway-mediated disorders.

Loss of properdin exacerbates C3 glomerulopathy resulting from factor H deficiency.

Complement factor H (CFH) is a negative regulator of the alternative pathway of complement, and properdin is the sole positive regulator. CFH-deficient mice (CFH(-/-)) develop uncontrolled C3 activation and spontaneous renal disease characterized by accumulation of C3 along the glomerular basement membrane, but the role of properdin in the pathophysiology is unknown. Here, we studied mice deficient in both CFH and properdin (CFH(-/-).P(-/-)). Although CFH(-/-) mice had plasma depleted of both C3 and C5, CFH(-/-).P(-/-) animals exhibited depletion of C3 predominantly, recapitulating the plasma complement profile observed in humans with properdin-independent C3 nephritic factors. Glomerular inflammation, thickening of the capillary wall, and glomerular C3 staining were significantly increased in CFH(-/-).P(-/-) compared with CFH(-/-) mice. We previously reported that exogenous CFH ameliorates C3 staining of the glomerular basement membrane and triggers the appearance of mesangial C3 deposits in CFH(-/-) mice; here, we show that these effects require properdin. In summary, during uncontrolled activation of C3 driven by complete CFH deficiency, properdin influences the intraglomerular localization of C3, suggesting that therapeutic inhibition of properdin would be detrimental in this setting.

Properdin Deficiency Impairs Phagocytosis and Enhances Injury at Kidney Repair Phase Post Ischemia-Reperfusion.

Properdin, a positive regulator of complement alternative pathway, participates in renal ischemia-reperfusion (IR) injury and also acts as a pattern-recognition molecule affecting apoptotic T-cell clearance. However, the role of properdin in tubular epithelial cells (TECs) at the repair phase post IR injury is not well defined. This study revealed that properdin knockout (PKO) mice exhibited greater injury in renal function and histology than wild-type (WT) mice post 72-h IR, with more apoptotic cells and macrophages in tubular lumina, increased active caspase-3 and HMGB1, but better histological structure at 24 h. Raised erythropoietin receptor by IR was furthered by PKO and positively correlated with injury and repair markers. Properdin in WT kidneys was also upregulated by IR, while H2O2-increased properdin in TECs was reduced by its small-interfering RNA (siRNA), with raised HMGB1 and apoptosis. Moreover, the phagocytic ability of WT TECs, analyzed by pHrodo Escherichia coli bioparticles, was promoted by H2O2 but inhibited by PKO. These results were confirmed by counting phagocytosed H2O2-induced apoptotic TECs by in situ end labeling fragmented DNAs but not affected by additional serum with/without properdin. Taken together, PKO results in impaired phagocytosis at the repair phase post renal IR injury. Properdin locally produced by TECs plays crucial roles in optimizing damaged cells and regulating phagocytic ability of TECs to effectively clear apoptotic cells and reduce inflammation.

Dexamethasone acutely suppresses the anabolic SNAT2/SLC38A2 amino acid transporter protein in L6-G8C5 rat skeletal muscle cells.

Chronic metabolic acidosis plays a role in cachexia by enhancing total proteolysis in skeletal muscle. Glucocorticoid also triggers proteolysis and plays a permissive role in the effect of acidosis. The System A amino acid transporter SNAT2/SLC38A2 is ubiquitously expressed in mammalian cells including muscle, performing Na+-dependent active import of neutral amino acids, and is strongly inhibited by low pH. Exposure of rat skeletal muscle cell line L6-G8C5 to low pH rapidly inhibits SNAT2 transport activity and enhances total proteolysis rate. Pharmacological inhibition or silencing of SNAT2 also enhances proteolysis. This study tests the hypothesis that the glucocorticoid dexamethasone (DEX), like low pH, inhibits SNAT2 activity in L6-G8C5 myotubes, thus contributing to total proteolysis. Incubation with 500 nM DEX for 4 h reduced the System A amino acid transport rate to half the rate in control cultures. This inhibition depended on glucocorticoid receptor-mediated gene transcription, but SNAT2 mRNA levels were unaffected by DEX. In contrast, the SNAT2 protein assessed by immunoblotting was significantly depleted. The co-inhibitory effects of DEX and low pH on System A transport activity were additive in stimulating total proteolysis. In keeping with this mechanism, DEX's inhibitory effect on SNAT2 transport activity was significantly blunted by the proteasome inhibitor MG132. Proof of principle was achieved in similar experiments using recombinant expression of a GFP-tagged SNAT2 fusion protein in HEK293A cells. It is concluded that DEX acutely depletes the SNAT2 transporter protein, at least partly through proteasome-dependent degradation of this functionally important transporter.

An Appraisal on the Value of Using Nutraceutical Based Senolytics and Senostatics in Aging.

The average human life expectancy has increased globally, and continues to rise, owing to the substantive progress made in healthcare, medicine, sanitation, housing and education. This ultimately enriches society with a greater proportion of elderly people. Sustaining a healthy aged population is key to diminish the societal and economic impact of age-related infirmities. This is especially challenging because tissue function, and thus wellbeing, naturally progressively decline as humans age. With age increasing the risk of developing diseases, one of the therapeutic options is to interfere with the molecular and cellular pathways involved in age-related tissue dysfunction, which is in part caused by the accumulation of senescent cells. One strategy to prevent this could be using drugs that selectively kill these cells (senolytics). In parallel, some compounds have been identified that prevent or slow down the progression of senescence or some of its features (senostatics). Senolytic and senostatic therapies have been shown to be efficient in vivo, but they also have unwanted dose-dependent side effects, including toxicity. Important advances might be made using bioactive compounds from plants and foods (nutraceuticals) if, as is proposed, they offer similar effectiveness with fewer side effects. The focus of this review is on the use of nutraceuticals in interfering with cellular senescence.

Prognostic Value of Complement Properdin in Cancer.

The complement system is readily triggered by the presence of damage-associated molecular patterns on the surface of tumor cells. The complement alternative pathway provides rapid amplification of the molecular stress signal, leading to complement cascade activation to deal with pathogens or malignant cells. Properdin is the only known positive regulator of the alternative pathway. In addition, properdin promotes the phagocytic uptake of apoptotic T cells by macrophages and dendritic cells without activating the complement system, thus, establishing its ability to recognize "altered-self". Dysregulation of properdin has been implicated in substantial tissue damage in the host, and in some cases, chronic unresolved inflammation. A corollary of this may be the development of cancer. Hence, to establish a correlation between properdin presence/levels in normal and cancer tissues, we performed bioinformatics analysis, using Oncomine and UALCAN. Survival analyses were performed using UALCAN and PROGgeneV2 to assess if properdin can serve as a potential prognostic marker for human lung adenocarcinoma (LUAD), liver hepatocellular carcinoma (LIHC), cervical squamous cell carcinoma (CESC), and pancreatic adenocarcinoma (PAAD). We also analyzed levels of tumor-infiltrating immune cells using TIMER, a tool for characterizing immune cell composition in cancers. We found that in LUAD and LIHC, there was a lower expression of properdin in the tumors compared to normal tissues, while no significant difference was observed in CESC and PAAD. Survival analysis demonstrated a positive association between properdin mRNA expression and overall survival in all 4 types of cancers. TIMER analysis revealed that properdin expression correlated negatively with tumor purity and positively with levels of infiltrating B cells, cytotoxic CD8+ T cells, CD4+ helper T cells, macrophages, neutrophils and dendritic cells in LUAD, CESC and PAAD, and with levels of B cells, CD8+ T cells and dendritic cells in LIHC. Immunohistochemical analysis revealed that infiltrating immune cells were the most likely source of properdin in the tumor microenvironment. Thus, complement protein properdin shows promise as a prognostic marker in cancer and warrants further study.

Ex vivo modelling of the formation of inflammatory platelet-leucocyte aggregates and their adhesion on endothelial cells, an early event in sepsis.

Septicaemia is an acute inflammatory reaction in the bloodstream to the presence of pathogen-associated molecular patterns. Whole blood stimulation assays capture endotoxin-induced formation of aggregates between platelets and leucocytes using flow cytometry. We wanted to assess extent of spontaneous aggregate formation in whole blood stimulation assays and compare the effects of endotoxin and heat-killed, clinically relevant, bacterial pathogens on aggregate formation and then on adhesion of aggregates to TNFα-stimulated endothelial cells. We found that endotoxin (from Escherichia coli or Salmonella enteritidis) was not a suitable stimulus to provoke platelet-leucocyte aggregates in vitro, as it did not further increase the extent of aggregates formed spontaneously in stasis of hirudin-anticoagulated blood. Specifically, whole blood samples stimulated with or without LPS produced aggregates with a mean surface area of 140.97 and 117.68 µm2, respectively. By contrast, incubation of whole blood with heat-killed Klebsiella pneumoniae or Staphylococcus aureus produced significantly enhanced and complex cellular aggregates (with a mean surface area of 470.61 and 518.39 µm2, respectively) which adhered more frequently to TNFα (and free fatty acid)-stimulated endothelial cells. These were reliably captured by scanning electron microscopy. Adhesion of cellular aggregates could be blocked by incubation of endothelial cells with a commercial P-selectin antibody and an angiopoietin-2 ligand trap. In conclusion, we have developed an in vitro method that models the acute inflammatory reaction in whole blood in the presence of sepsis-relevant bacterial pathogen surfaces.

In vitro Generation of Cytotoxic T Cells With Potential for Adoptive Tumor Immunotherapy of Multiple Myeloma.

Multiple myeloma is a life-threatening hematological malignancy, which is rarely curable by conventional therapies. Immunotherapy, using tumor antigen-specific, cytotoxic T-lymphocytes, may represent an alternative or additional treatment for multiple myeloma. In this study, we used hybrid cell lines, generated by fusion of an EBV B-lymphoblastoid cell line (B-LCL) and myeloma cells, to stimulate in vitro peripheral blood lymphocytes (PBLs) from patients with multiple myeloma. We investigated induction of antigen-specific, cytotoxic T-lymphocytes to the well-defined tumor associated antigens (TAAs) hTERT, MUC1, MAGE-C1 and CS1, which have been shown to be expressed in a high proportion of cases of multiple myeloma. HLA-A2-peptide pentamer staining, interferon-γ and perforin ELISpot assays, as well as cytotoxicity assays were used. Following several rounds of in vitro stimulation, the hybrid cell lines induced antigen-specific, cytotoxic T-lymphocytes to four candidate TAAs in PBLs from HLA-A2+ multiple myeloma patients, using known HLA-A2 restricted peptide epitopes of the TAAs. In contrast, the HLA-A2+ myeloma cell line U266 failed to induce antigen-specific, cytotoxic T-lymphocytes in vitro. Our data indicate that B-LCL/myeloma hybrid cell lines induce antigen-specific, cytotoxic T-lymphocytes in PBLs isolated from multiple myeloma patients in vitro and may represent a novel strategy for use in adoptive immunotherapy of multiple myeloma.

Human Properdin Opsonizes Nanoparticles and Triggers a Potent Pro-inflammatory Response by Macrophages without Involving Complement Activation.

Development of nanoparticles as tissue-specific drug delivery platforms can be considerably influenced by the complement system because of their inherent pro-inflammatory and tumorigenic consequences. The complement activation pathways, and its recognition subcomponents, can modulate clearance of the nanoparticles and subsequent inflammatory response and thus alter the intended translational applications. Here, we report, for the first time, that human properdin, an upregulator of the complement alternative pathway, can opsonize functionalized carbon nanotubes (CNTs) via its thrombospondin type I repeat (TSR) 4 and 5. Binding of properdin and TSR4+5 is likely to involve charge pattern/polarity recognition of the CNT surface since both carboxymethyl cellulose-coated carbon nanotubes (CMC-CNT) and oxidized (Ox-CNT) bound these proteins well. Properdin enhanced the uptake of CMC-CNTs by a macrophage cell line, THP-1, mounting a robust pro-inflammatory immune response, as revealed by qRT-PCR, multiplex cytokine array, and NF-κB nuclear translocation analyses. Properdin can be locally synthesized by immune cells in an inflammatory microenvironment, and thus, its interaction with nanoparticles is of considerable importance. In addition, recombinant TSR4+5 coated on the CMC-CNTs inhibited complement consumption by CMC-CNTs, suggesting that nanoparticle decoration with TSR4+5, can be potentially used as a complement inhibitor in a number of pathological contexts arising due to exaggerated complement activation.

In vitro Modulation of the LPS-Induced Proinflammatory Profile of Hepatocytes and Macrophages- Approaches for Intervention in Obesity?

Low grade endotoxemia is a feature of obesity which is linked to development of steatohepatitis in non-alcoholic fatty liver disease. In this study, macrophages (J774) and hepatocytes (HepG2) were stimulated with lipopolysaccharide (LPS) from E. coli 0111: B4 and analyzed for modulation of this response when preconditioned or stimulated subsequent to LPS, with different doses of Vitamin D3 or docosahexaenoic acid (DHA) over a time period of 1 and 5 days. Pro-inflammatory TNFα and pro-fibrotic TGFß released into the supernatants were measured by ELISA; qPCR was performed for Srebp-1c and PPARα mRNA (genes for products involved in fatty acid synthesis and catabolism, respectively). Vitamin D3 and DHA exerted a consistent, dose dependent anti-inflammatory effect, and increased PPARα relative to Srebp-1c in both cell types. By contrast, addition of free fatty acids (FFA, oleic acid/palmitic acid 2:1) caused aggravation of LPS-induced inflammatory reaction and an increase of Srebp-1c relative to PPARα. Our results argue in favor of dietary supplementation of Vitamin D3 or DHA (and avoidance of monounsaturated/saturated fatty acids) to alleviate development of fatty liver disease.

P. gingivalis in Periodontal Disease and Atherosclerosis - Scenes of Action for Antimicrobial Peptides and Complement.

According to the NHS, it is estimated that over 50% of the adult population are, to some extent, affected by gum disease and approximately 15% of UK population have been diagnosed with severe periodontitis. Periodontitis, a chronic polymicrobial disease of the gums, causes inflammation in its milder form, whereas in its severe form affects the surrounding tissues and can result in tooth loss. During periodontitis, plaque accumulates and sits between the junctional epithelium and the tooth itself, resulting in inflammation and the formation of a periodontal pocket. An interface is formed directly between the subgingival bacteria and the junctional epithelial cells. Bacterial pathogens commonly associated with periodontal disease are, among others, Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola, together known as the "red complex." This review will mostly concentrate on the role of P. gingivalis, a Gram-negative anaerobic bacterium and one of the major and most studied contributors of this disease. Because periodontal disease is associated with the development of atherosclerosis, it is important to understand the local immune response to P. gingivalis. Innate immune players, in particular, complement and antimicrobial peptides and their effects with regard to P. gingivalis during periodontitis and in the development of atherosclerosis will be presented.