Effects of 15d-PGJ₂-loaded poly(D,L-lactide-co-glycolide) nanocapsules on inflammation

PPAR-γ Agonist GW1929 Targeted to Macrophages with Dendrimer-Graphene Nanostars Reduces Liver Fibrosis and Inflammation

Macrophages play essential roles during the progression of chronic liver disease. They actively participate in the response to liver damage and in the balance between fibrogenesis and regression. The activation of the PPARγ nuclear receptor in macrophages has traditionally been associated with an anti-inflammatory phenotype. However, there are no PPARγ agonists with high selectivity for macrophages, and the use of full agonists is generally discouraged due to severe side effects. We designed dendrimer-graphene nanostars linked to a low dose of the GW1929 PPARγ agonist (DGNS-GW) for the selective activation of PPARγ in macrophages in fibrotic livers. DGNS-GW preferentially accumulated in inflammatory macrophages in vitro and attenuated macrophage pro-inflammatory phenotype. The treatment with DGNS-GW in fibrotic mice efficiently activated liver PPARγ signaling and promoted a macrophage switch from pro-inflammatory M1 to anti-inflammatory M2 phenotype. The reduction of hepatic inflammation was associated with a significant reduction in hepatic fibrosis but did not alter liver function or hepatic stellate cell activation. The therapeutic antifibrotic utility of DGNS-GW was attributed to an increased expression of hepatic metalloproteinases that allowed extracellular matrix remodeling. In conclusion, the selective activation of PPARγ in hepatic macrophages with DGNS-GW significantly reduced hepatic inflammation and stimulated extracellular matrix remodeling in experimental liver fibrosis.

Autologous Bone Marrow Mononuclear Cells (BMMC)-Associated Anti-Inflammatory Nanoparticles for Cardiac Repair after Myocardial Infarction

To investigate the effect of transplantation of stem cells from the bone marrow mononuclear cells (BMMC) associated with 15d-PGJ2-loaded nanoparticles in a rat model of chronic MI. Chronic myocardial infarction (MI) was induced by the ligation of the left anterior descending artery in 40 male Wistar rats. After surgery, we transplanted bone marrow associated with 15d-PGJ2-loaded nanoparticle by intramyocardial injection (10⁶ cells/per injection) seven days post-MI. Myocardial infarction was confirmed by echocardiography, and histological analyses of infarct morphology, gap junctions, and angiogenesis were obtained. Our results from immunohistochemical analyses demonstrated the presence of angiogenesis identified in the transplanted region and that there was significant expression of connexin-43 gap junctions, showing a more effective electrical and mechanical integration of the host myocardium. This study suggests that the application of nanoparticle technology in the prevention and treatment of MI is an emerging field and can be a strategy for cardiac repair.

Harnessing Inflammation Resolution in Arthritis: Current Understanding of Specialized Pro-resolving Lipid Mediators' Contribution to Arthritis Physiopathology and Future Perspectives

The concept behind the resolution of inflammation has changed in the past decades from a passive to an active process, which reflects in novel avenues to understand and control inflammation-driven diseases. The time-dependent and active process of resolution phase is orchestrated by the endogenous biosynthesis of specialized pro-resolving lipid mediators (SPMs). Inflammation and its resolution are two forces in rheumatic diseases that affect millions of people worldwide with pain as the most common experienced symptom. The pathophysiological role of SPMs in arthritis has been demonstrated in pre-clinical and clinical studies (no clinical trials yet), which highlight their active orchestration of disease control. The endogenous roles of SPMs also give rise to the opportunity of envisaging these molecules as novel candidates to improve the life quality of rhematic diseases patients. Herein, we discuss the current understanding of SPMs endogenous roles in arthritis as pro-resolutive, protective, and immunoresolvent lipids.

Engineering Polymeric Nanosystems against Oral Diseases

Nanotechnology and nanoparticles (NPs) are at the forefront of modern research, particularly in the case of healthcare therapeutic applications. Polymeric NPs, specifically, hold high promise for these purposes, including towards oral diseases. Careful optimisation of the production of polymeric NPs, however, is required to generate a product which can be easily translated from a laboratory environment to the actual clinical usage. Indeed, considerations such as biocompatibility, biodistribution, and biodegradability are paramount. Moreover, a pre-clinical assessment in adequate in vitro, ex vivo or in vivo model is also required. Last but not least, considerations for the scale-up are also important, together with an appropriate clinical testing pathway. This review aims to eviscerate the above topics, sourcing at examples from the recent literature to put in context the current most burdening oral diseases and the most promising polymeric NPs which would be suitable against them.

Effects of nanocapsules of poly-ε-caprolactone containing artemisinin on zebrafish early-life stages and adults

Artemisinin extracted from Artemisia annua L. plants has a range of properties that qualifies it to treat several diseases, such as malaria and cancer. However, it has short half-life, which requires making continuous use of it, which has motivated the association of artemisinin (ART) with polymeric nanoparticles to increase its therapeutic efficiency. However, the ecotoxicological safety of this association has been questioned, given the scarcity of studies in this area. Thus, in this work the toxicity of Poly (ε-Caprolactone) nanocapsules added with ART (ART-NANO) in zebrafish (Danio rerio), embryos and adults was studied. Different endpoints were analyzed in organisms exposed to ART-NANO, including those predictive of embryotoxicity and histopatoxicity. Embryotoxicity was analyzed based on Organization for Economic Co-operation and Development (OECD) test guideline (236) for fish embryo acute toxicity applied to zebrafish (Danio rerio) at 96 hpf under five nominal logarithmic concentrations (0.125 to 2.0 mg/ L). Our results demonstrate, mainly, that fertilized eggs presented increased coagulation, lack of heart rate, vitelline sac displacement and lack of somite formation. On the other hand, adult individuals (exposed to the same concentrations and evaluated after 24 and 96 h of exposure) have shown increased pericarditis. Therefore, the treatment based on ART, poly (ε-caprolactone) nanocapsules and on their combination at different concentrations have shown toxic effects on zebrafish embryos and adult individuals.

Mycolactone toxin induces an inflammatory response by targeting the IL-1β pathway: Mechanistic insight into Buruli ulcer pathophysiology

Mycolactone, a lipid-like toxin, is the major virulence factor of Mycobacterium ulcerans, the etiological agent of Buruli ulcer. Its involvement in lesion development has been widely described in early stages of the disease, through its cytotoxic and immunosuppressive activities, but less is known about later stages. Here, we revisit the role of mycolactone in disease outcome and provide the first demonstration of the pro-inflammatory potential of this toxin. We found that the mycolactone-containing mycobacterial extracellular vesicles produced by M. ulcerans induced the production of IL-1β, a potent pro-inflammatory cytokine, in a TLR2-dependent manner, targeting NLRP3/1 inflammasomes. We show our data to be relevant in a physiological context. The in vivo injection of these mycolactone-containing vesicles induced a strong local inflammatory response and tissue damage, which were prevented by corticosteroids. Finally, several soluble pro-inflammatory factors, including IL-1β, were detected in infected tissues from mice and Buruli ulcer patients. Our results revisit Buruli ulcer pathophysiology by providing new insight, thus paving the way for the development of new therapeutic strategies taking the pro-inflammatory potential of mycolactone into account.

Buruli ulcer is a neglected tropical disease occurring mainly in poor rural areas of West and Central Africa. This cutaneous disease is caused by Mycobacterium ulcerans, a bacterium belonging to the same family as M. tuberculosis and M. leprae. The skin lesions are caused by a cytotoxic toxin named mycolactone, also known to act as an immunosuppressor and an anti-inflammatory molecule. However, Buruli ulcer lesions are characterized by a chronic cutaneous inflammation with a recruitment of cellular immune cells trying to counteract M. ulcerans. Our work allows for a reconcilitation of previous observations. We found by in vitro experiment on macrophages that the mycolactone-containing mycobacterial extracellular vesicles produced by M. ulcerans induced the production of IL-1β, a potent pro-inflammatory molecule, while other pro-inflammatory soluble factors are inhibited. We also detected IL-1β protein in a mouse model of M. ulcerans infection as well as in biopsies of Buruli ulcer patients. The pro-inflammatory potential of mycolacone has to be taken into account to understand the full pathophysiology of Buruli ulcer.

The 15d‑PGJ2 hydrogel ameliorates atopic dermatitis through suppression of the immune response

The present study examined the efficacy of the topical 15d-PGJ₂-poloxamer 407 hydrogel in an atopic dermatitis (AD) animal model. The 15d-PGJ₂ hydrogel was prepared and characterized. The examined rats possessed AD-Like cutaneous lesions, which were induced using 2,4-dinitrochlorobenzene, the rats were then treated with a hydrogel vehicle, 15d-PGJ₂ hydrogel or tacrolimus for 14 days. The rats were sacrificed and blood samples were collected to quantify the IgE levels. Subsequently, skin biopsies were stained with toluidine blue to identify mast cells and immunohistochemistry was performed for ROR-γt and TNF-α. Histological analyses demonstrated that 15d-PGJ₂ hydrogel significantly decreased mast cell infiltration (P<0.05) when compared with the AD-group. Tacrolimus at 0.1% exhibited decreased mast cell infiltration; however, this difference was not statistically significant from the AD-group. Topical 15d-PGJ₂ hydrogel and Tacrolimus 0.1% significantly reduced the serum levels of IgE (P<0.05) compared with the AD-group. Immunohistochemistry revealed a significant decrease in ROR-γt and TNF-α positive cell expression (P<0.05) in the 15d-PGJ₂ hydrogel group compared with the AD-group. In summary, topical administration of 15d-PGJ₂ hydrogel had a beneficial effect on AD symptoms, suggesting that this formulation may be a useful strategy for the treatment of AD.

Apolipoprotein D overexpression alters hepatic prostaglandin and omega fatty acid metabolism during the development of a non-inflammatory hepatic steatosis

Apolipoprotein D (ApoD) is a secreted lipocalin associated with neuroprotection and lipid metabolism. Overexpression of ApoD in mouse neural tissue induces the development of a non-inflammatory hepatic steatosis in 12-month-old transgenic animals. Previous data indicates that accumulation of arachidonic acid, ApoD's preferential ligand, and overactivation of PPARγ are likely the driving forces in the development of the pathology. However, the lack of inflammation under those conditions is surprising. Hence, we further investigated the apparent repression of inflammation during hepatic steatosis development in aging transgenic animals. The earliest modulation of lipid metabolism and inflammation occurred at 6 months with a transient overexpression of L-PGDS and concomitant overproduction of 15d-PGJ₂, a PPARγ agonist. Hepatic lipid accumulation was detectable as soon as 9 months. Inflammatory polarization balance varied in time, with a robust anti-inflammatory profile at 6 months coinciding with 15d-PGJ₂ overproduction. Omega-3 and omega-6 fatty acids were preferentially stored in the liver of 12-month-old transgenic mice and resulted in a higher omega-3/omega-6 ratio compared to wild type mice of the same age. Thus, inflammation seems to be controlled by several mechanisms in the liver of transgenic mice: first by an increase in 15d-PGJ₂ production and later by a beneficial omega-3/omega-6 ratio. PPARγ seems to play important roles in these processes. The accumulation of several omega fatty acids species in the transgenic mouse liver suggests that ApoD might bind to a broader range of fatty acids than previously thought.

15d-PGJ2-loaded nanocapsules ameliorate experimental gout arthritis by reducing pain and inflammation in a PPAR-gamma-sensitive manner in mice

Gout arthritis (GA) is a painful inflammatory disease in response to monosodium urate (MSU) crystals in the joints. 15deoxy-Δ^12,14-prostaglandin J₂ (15d-PGJ₂) is a natural activator of PPAR-γ with analgesic, anti-inflammatory, and pro-resolution properties. Thus, we aimed to evaluate the effect and mechanisms of action of 15d-PGJ₂ nanocapsules (NC) in the model of GA in mice, since a reduction of 33-fold in the dose of 15d-PGJ₂ has been reported. Mice were treated with 15d-PGJ₂-loaded NC, inert NC, free 15d-PGJ₂ (without NC), or 15d-PGJ₂-loaded NC+ GW9662, a PPAR-γ inhibitor. We show that 15d-PGJ₂-loaded NC provided analgesic effect in a dose that the free 15d-PGJ₂ failed to inhibiting pain and inflammation. Hence, 15d-PGJ₂-loaded NC reduced MSU-induced IL-1β, TNF-α, IL-6, IL-17, and IL-33 release and oxidative stress. Also, 15d-PGJ₂-loaded NC decreased the maturation of IL-1β in LPS-primed BMDM triggered by MSU. Further, 15d-PGJ₂-loaded NC decreased the expression of the components of the inflammasome Nlrp3, Asc, and Pro-caspase-1, as consequence of inhibiting NF-κB activation. All effects were PPAR-γ-sensitive. Therefore, we demonstrated that 15d-PGJ₂-loaded NC present analgesic and anti-inflammatory properties in a PPAR-γ-dependent manner inhibiting IL-1β release and NF-κB activation in GA. Concluding, 15d-PGJ₂-loaded NC ameliorates MSU-induced GA in a PPAR-γ-sensitive manner.

Effect of 15-Deoxy-Δ12,14-prostaglandin J2Nanocapsules on Inflammation and Bone Regeneration in a Rat Bone Defect Model

BACKGROUND

15-Deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2), one of the major metabolites from prostaglandin D2 in arachidonic acid metabolic pathway, has potential anti-inflammatory properties. The objective of this study was to explore the effects of 15d-PGJ2-loaded poly(D,L-lactide-co-glycolide) nanocapsules (15d-PGJ2-NC) on inflammatory responses and bone regeneration in local bone defect.

METHODS

The study was conducted on 96 Wistar rats from June 2014 to March 2016. Saline, unloaded nanoparticles, free 15d-PGJ2or 15d-PGJ2-NC, were delivered through a collagen vehicle inside surgically created transcortical defects in rat femurs. Interleukin-6 (IL-6), interleukin-1 beta (IL-1β), and tumor necrosis factor-alpha (TNF-α) levels in the surrounding soft tissue were analyzed by Western blot and in the defect by quantitative real-time polymerase chain reaction over 14 days. Simultaneously, bone morphogenetic protein-6 (BMP-6) and platelet-derived growth factor-B (PDGF-B) messenger RNA (mRNA) in the defect were examined. New bone formation and EphrinB2 and osteoprotegerin (OPG) protein expression in the cortical defect were observed by Masson's Trichrome staining and immunohistochemistry over 28 days. Data were analyzed by one-way analysis of variance. Least-significant difference and Dunnett's T3 methods were used with a bilateral P< 0.05.

RESULTS

Application of l5d-PGJ2-NC (100 μg/ml) in the local bone defect significantly decreased IL-6, IL-1β, and TNF-α mRNA and protein, compared with saline-treated controls (P < 0.05). l5d-PGJ2-NC upregulated BMP-6 and PDGF-B mRNA (P < 0.05). New bone formation was observed in the cortical defect in l5d-PGJ2-NC-treated animals from 7th day onward (P < 0.001). Expression of EphrinB2 and OPG presented early on day 3 and persisted through day 28 in 15d-PGJ2-NC group (P < 0.05).

CONCLUSION

Stable l5d-PGJ2-NC complexes were prepared that could attenuate IL-6, IL-1β, and TNF-α expression, while increasing new bone formation and growth factors related to bone regeneration.

15d-PGJ2-Loaded Solid Lipid Nanoparticles: Physicochemical Characterization and Evaluation of Pharmacological Effects on Inflammation

15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2), a peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist, has physiological properties including pronounced anti-inflammatory activity, though it binds strongly to serum albumin. The use of solid lipid nanoparticles (SLN) can improve therapeutic properties increasing drug efficiency and availability. 15d-PGJ2-SLN was therefore developed and investigated in terms of its immunomodulatory potential. 15d-PGJ2-SLN and unloaded SLN were physicochemically characterized and experiments in vivo were performed. Animals were pretreated with 15d-PGJ2-SLN at concentrations of 3, 10 or 30 μg·kg-1 before inflammatory stimulus with carrageenan (Cg), lipopolysaccharide (LPS) or mBSA (immune response). Interleukins (IL-1β, IL-10 and IL-17) levels were also evaluated in exudates. The 15d-PGJ2-SLN system showed good colloidal parameters and encapsulation efficiency of 96%. The results showed that the formulation was stable for up to 120 days with low hemolytic effects. The 15d-PGJ2-SLN formulation was able to reduce neutrophil migration in three inflammation models tested using low concentrations of 15d-PGJ2. Additionally, 15d-PGJ2-SLN increased IL-10 levels and reduced IL-1β as well as IL-17 in peritoneal fluid. The new 15d-PGJ2-SLN formulation highlights perspectives of a potent anti-inflammatory system using low concentrations of 15d-PGJ2.

The low molecular weight fraction of human serum albumin upregulates production of 15d-PGJ2 in Peripheral Blood Mononuclear Cells

Activation of the innate immune system involves a series of events designed to counteract the initial insult followed by the clearance of debris and promotion of healing. Aberrant regulation can lead to systemic inflammatory response syndrome, multiple organ failure, and chronic inflammation. A better understanding of the innate immune response may help manage complications while allowing for proper immune progression. In this study, the ability of several classes of anti-inflammatory drugs to affect LPS-induced cytokine and prostaglandin release from peripheral blood mononuclear cells (PBMC) was evaluated. PBMC were cultured in the presence of dexamethasone (DEX), ibuprofen (IBU), and the low molecular weight fraction of 5% albumin (LMWF5A) followed by stimulation with LPS. After 24 h, TNFα, PGE2, and 15d-PGJ2 release was determined by ELISA. Distinct immunomodulation patterns emerged following LPS stimulation of PBMC in the presence of said compounds. DEX, a steroid with strong immunosuppressive properties, reduced TNFα, PGE2, and 15d-PGJ2 release. IBU caused significant reduction in prostaglandin release while TNFα release was unchanged. An emerging biologic with known anti-inflammatory properties, LMWF5A, significantly reduced TNFα release while enhancing PGE2 and 15d-PGJ2 release. Incubating LMWF5A together with IBU negated this observed increased prostaglandin release without affecting the suppression of TNFα release. Additionally, LMWF5A caused an increase in COX-2 transcription and translation. LMWF5A exhibited a unique immune modulation pattern in PBMC, disparate from steroid or NSAID administration. This enhancement of prostaglandin release (specifically 15d-PGJ2), in conjunction with a decrease in TNFα release, suggests a switch that favors resolution and decreased inflammation.

Inflammatory Pathways in Knee Osteoarthritis: Potential Targets for Treatment

Osteoarthritis (OA) of the knee is a wide-spread, debilitating disease that is prominent in Western countries. It is associated with old age, obesity, and mechanical stress on the knee joint. By examining the recent literature on the effect of the anti-inflammatory prostaglandins 15d-PGJ2 and Δ12-PGJ2, we propose that new therapeutic agents for this disease could facilitate the transition from the COX-2-dependent pro-inflammatory synthesis of the prostaglandin PGE2 (catalyzed by mPGES-1), to the equally COX-2-dependent synthesis of the aforementioned anti-inflammatory prostaglandins. This transition could be instrumental in halting the breakdown of cartilage via matrix metalloproteinases (MMPs) and aggrecanases, as well as promoting the matrix regeneration and synthesis of cartilage by chondrocytes. Another desirable property of new OA therapeutics could involve the recruitment of mesenchymal stem cells to the damaged cartilage and bone, possibly resulting in the generation of chondrocytes, synoviocytes, and, in the case of bone, osteoblasts. Moreover, we propose that research promoting this transition from pro-inflammatory to anti-inflammatory prostaglandins could aid in the identification of new OA therapeutics.

The cyclopentenone prostaglandin 15d-PGJ2 inhibits the NLRP1 and NLRP3 inflammasomes

Inflammasomes are cytosolic protein complexes that respond to diverse danger signals by activating caspase-1. The sensor components of the inflammasome, often proteins of the nucleotide-binding oligomerization domain-like receptor (NLR) family, detect stress, danger stimuli, and pathogen-associated molecular patterns. We report that the eicosanoid 15-deoxy-Δ(12,14)-PGJ2 (15d-PGJ2) and related cyclopentenone PGs inhibit caspase-1 activation by the NLR family leucine-rich repeat protein (NLRP)1 and NLRP3 inflammasomes. This inhibition was independent of the well-characterized role of 15d-PGJ2 as a peroxisome proliferator receptor-γ agonist, its activation of NF erythroid 2-related factor 2, or its anti-inflammatory function as an inhibitor of NF-κB. Instead, 15d-PGJ2 prevents the autoproteolytic activation of caspase-1 and the maturation of IL-1β through induction of a cellular state inhibitory to caspase-1 proteolytic function. The eicosanoid does not directly modify or inactivate the caspase-1 enzyme. Rather, inhibition is dependent on de novo protein synthesis. In a mouse peritonitis model of gout, using monosodium urate crystals to activate NLRP3, 15d-PGJ2 caused a significant inhibition of cell recruitment and associated IL-1β release. Furthermore, in a murine anthrax infection model, 15d-PGJ2 reversed anthrax lethal toxin-mediated NLRP1-dependent resistance. The findings reported in this study suggest a novel mechanism for the anti-inflammatory properties of the cyclopentenone PGs through inhibition of caspase-1 and the inflammasome.

15-Deoxy- γ 12,14-prostaglandin J2 Reduces Liver Impairment in a Model of ConA-Induced Acute Hepatic Inflammation by Activation of PPAR γ and Reduction in NF- κ B Activity

Objective. 15-Deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) reduces inflammation and has been identified as an anti-inflammatory prostaglandin in numerous animal models. In this study, we investigated both effects of 15d-PGJ2 and its protection mechanism in concanavalin A- (ConA-) induced autoimmune hepatitis in mice. Materials and Methods. In vivo, Balb/C mice were injected with ConA (25 mg/kg) to induce acute autoimmune hepatitis, and 15d-PGJ2 (10 μg or 25 μg) was administered 1 h before the ConA injection. The histological grade, proinflammatory cytokine levels, and NF-κB and PPARγ activity were determined 6, 12, and 24 h after the ConA injection. In vitro, LO2 cells and RAW264.7 cells were pretreated with 15d-PGJ2 (2 μM) 1 h before the stimulation with ConA (30 μg/mL). The NF-κB and PPARγ activity were determined 30 min after the ConA administration. Results. Pretreatment with 15d-PGJ2 reduced the pathological effects of ConA-induced autoimmune hepatitis and significantly reduced the levels of cytokines after injection. 15d-PGJ2 activated PPARγ, blocked the degradation of IκBα, and inhibited the translocation of NF-κB into the nucleus. Conclusion. These results indicate that 15d-PGJ2 protects against ConA-induced autoimmune hepatitis by reducing proinflammatory cytokines. This reduction in inflammation may correlate with the activation of PPARγ and the reduction in NF-κB activity.

Fluid shear stress-induced osteoarthritis: roles of cyclooxygenase-2 and its metabolic products in inducing the expression of proinflammatory cytokines and matrix metalloproteinases

The mechanical overloading of cartilage is involved in the pathophysiology of osteoarthritis (OA) by both biochemical and mechanical pathways. The application of fluid shear stress to chondrocytes recapitulates the earmarks of OA, as evidenced by the release of proinflammatory cytokines (PICs), matrix metalloproteinases (MMPs), and apoptotic factors. Dysregulations or mutations in these genes might directly cause OA in addition to determining the stage at which OA becomes apparent, the joint sites involved, and the severity of the disease and how rapidly it progresses. However, the underlying mechanisms remain unknown. In this review, we propose that the dysregulation of cyclooxygenase-2 (COX-2) is associated with fluid shear stress-induced OA via its metabolic products at different stages of the disease. Indeed, high fluid shear stress rapidly induces the production of PICs and MMPs via COX-2-derived prostaglandin (PG)E2 at the early stage of OA. In contrast, prolonged shear exposure (>12 h) aggravates the condition by concurrently up-regulating the expression of proapoptotic genes and down-regulating the expression of antiapoptotic genes in a 15-deoxy-Δ (12,14)-prostaglandin J2 (15d-PGJ2)-dependent manner at the late stage of disease. These observations may help to resolve long-standing questions in OA progression and provide insight for development of strategies to treat and combat OA.

L-diphenylalanine microtubes as a potential drug-delivery system: characterization, release kinetics, and cytotoxicity

Microtubes obtained from the self-assembly of L-diphenylalanine (FF-MTs) were evaluated as potential vehicles for drug delivery. The biological marker Rhodamine B (RhB) was chosen as a model drug and conjugated to the peptide arrays during self-organization in the liquid phase. Microscopy and X-ray studies were performed to provide morphological and structural information. The data revealed that the cargo was distributed either in small aggregates at the hydrophobic surface of the FF-MTs or homogeneously embedded in the structure, presumably anchored at polar sites in the matrix. Raman spectroscopy revealed notable shifts of the characteristic RhB resonance peaks, demonstrating the successful conjugation of the fluorophore and peptide assemblies. In vitro assays were conducted in erythrocytes and fibroblast cells. Interestingly, FF-MTs were found to modulate the release of the load. The release of RhB from the FF-MTs followed first-order kinetics with a steady-state profile, demonstrating the potential of these carriers to deliver drugs at constant rates in the body. Cytotoxicity investigations revealed high cell viability up to concentrations of 5 mg mL(-1), demonstrating the low toxicity of the FF-MTs.

15-Deoxy-Δ12,14-prostaglandin J2 inhibits macrophage colonization by Salmonella enterica serovar Typhimurium

15-deoxy-Δ^12,14-prostaglandin J₂ (15d-PGJ₂) is an anti-inflammatory downstream product of the cyclooxygenase enzymes. It has been implicated to play a protective role in a variety of inflammatory mediated diseases, including rheumatoid arthritis, neural damage, and myocardial infarctions. Here we show that 15d-PGJ₂ also plays a role in Salmonella infection. Salmonella enterica Typhimurium is a Gram-negative facultative intracellular pathogen that is able to survive and replicate inside phagocytic immune cells, allowing for bacterial dissemination to systemic sites. Salmonella species cause a wide range of morbidity and mortality due to gastroenteritis and typhoid fever. Previously we have shown that in mouse models of typhoid fever, Salmonella infection causes a major perturbation in the prostaglandin pathway. Specifically, we saw that 15d-PGJ₂ production was significantly increased in both liver and feces. In this work we show that 15d-PGJ₂ production is also significantly increased in macrophages infected with Salmonella. Furthermore, we show that the addition of 15d-PGJ₂ to Salmonella infected RAW264.7, J774, and bone marrow derived macrophages is sufficient to significantly reduce bacterial colonization. We also show evidence that 15d-PGJ₂ is reducing bacterial uptake by macrophages. 15d-PGJ₂ reduces the inflammatory response of these infected macrophages, as evidenced by a reduction in the production of cytokines and reactive nitrogen species. The inflammatory response of the macrophage is important for full Salmonella virulence, as it can give the bacteria cues for virulence. The reduction in bacterial colonization is independent of the expression of Salmonella virulence genes SPI1 and SPI2, and is independent of the 15d-PGJ₂ ligand PPAR-γ. 15d-PGJ₂ also causes an increase in ERK1/2 phosphorylation in infected macrophages. In conclusion, we show here that 15d-PGJ₂ mediates the outcome of bacterial infection, a previously unidentified role for this prostaglandin.

Rosiglitazone-loaded nanospheres for modulating macrophage-specific inflammation in obesity

PPARγ nuclear receptor agonists have been shown to attenuate macrophage inflammatory responses implicated in the metabolic complications of obesity and in atherosclerosis. However, PPARγ agonists currently in clinical use, including rosiglitazone (RSG), are often associated with severe side effects that limit their therapeutic use. Here, 200nm PLGA/PVA nanospheres were formulated for the systemic delivery of RSG specifically to macrophages. RSG was encapsulated with over 50% efficiency in the hydrophobic PLGA core and released specifically within the acidifying macrophage phagosomes. In bone marrow derived macrophages, RSG-loaded nanoparticles (RSG-NPs) induce a dose dependent upregulation (1.5 to 2.5-fold) of known PPARγ target genes, with maximal induction at 5μM; and downregulate the expression of genes related to the inflammatory process, with a maximum effect at 10μM. In Ldlr(-/-) mice fed high fat diet, treatment with RSG-NPs alleviated inflammation in white adipose tissue and liver but, unlike treatment with free RSG, did not alter genes associated with lipid metabolism or cardiac function, indicating a reduction in the RSG side effect profile. These biocompatible, biodegradable RSG-NPs represent a preliminary step towards the specific delivery of nuclear receptor agonists for the treatment of macrophage-mediated inflammatory conditions associated with obesity, atherosclerosis and other chronic disease states.

Low doses of 15d-PGJ2 induce osteoblast activity in a PPAR-gamma independent manner

Peroxisome proliferator-activated receptor-gamma (PPARγ) regulates both glucose metabolism and bone mass. Evidence suggests that the therapeutic modulation of PPARγ with synthetic agonists activity may elicit undesirable effects on bone. However, there is no information regarding its natural agonist 15d-PGJ2, besides its excellent anti-inflammatory action. In the present study the effects of 15d-PGJ2 on osteoblastic cells were determined. Osteoblastic cells (MC3T3) were cultured in an osteogenic medium in the presence of 1, 3 or 10 μM of 15d-PGJ2 during 21 days and alizarin and Von Kossa staining were employed. The protein expression (type-I collagen, osteonectin, osteopontin, RANKL, osteoprotegerin, HDAC-9c and PPAR-γ) was evaluated after 3 days in the presence of 15d-PGJ2 by western blotting and indirect immunofluorescence methods. The production of mineralized extracellular matrix was observed by transmission electron microscopy. After 72 h of culture, the mRNA was extracted for RT-qPCR analysis of RUNX expression. In the presence of all 3 tested 15d-PGJ2 doses, alizarin red and Von kossa staining were positive demonstrating the ability to the osteoblast differentiation. Type-I collagen and osteonectin proteins expression were up-regulated (p < 0.05) after 72 h in the presence of the smaller doses of 15d-PGJ2. In contrast, osteopontin, RANKL and OPG expression did not significantly alter. In the presence of 15d-PGJ2 it was possible to visualize mineralized nodules in the extracellular matrix confirmed with the increased RUNX mRNA expression. 15d-PGJ2 at small doses increased the osteoblast activity and the bone-related proteins expression.

PPARγ ligand treatment inhibits cardiac inflammatory mediators induced by infection with different lethality strains of Trypanosoma cruzi

Trypanosoma cruzi (T. cruzi), the etiological agent of Chagas' disease, causes cardiac alterations in the host. Although the main clinical manifestations arise during the chronic stage, the mechanisms leading to heart damage develop early during infection. In fact, an intense inflammatory response is observed from acute stage of infection. Recently, peroxisome proliferator-activated receptors (PPARs) have attracted research interest due to their participation in the modulation of inflammation. In this work we addressed the role of 15-Deoxy-∆(12,14) ProstaglandinJ2 (15dPGJ2), a PPARγ natural ligand in the regulation of inflammatory mediators, in acute and chronic experimental mouse models of Chagas' disease with the RA and K98 T. cruzi strains, respectively. This work demonstrates that 15dPGJ2 treatment inhibits the expression and activity of inducible nitric oxide synthase (NOS2) as well as TNF-α and IL-6 mRNA levels. Also, expression and activity of metalloproteinases 2 (MMP-2) and 9 (MMP9) were inhibited by 15dPGJ2. Moreover GW9662, a specific PPARγ antagonist, revealed the participation of other signaling pathways since, in GW9662 presence, 15dPJG2 had a partial effect on the inhibition of inflammatory parameters in the acute model of infection. Accordingly, NF-κB activation was demonstrated, assessing p65 nuclear translocation in the hearts of infected mice with both T. cruzi strains. Such effect was inhibited after 15dPGJ2 treatment. Our findings support the concept that in vivo PPARγ and NF-κB pathways are implicated in the inhibitory effects of 15dPGJ2 on inflammatory mediators at different times depending on whether the infection is caused by the lethal or non-lethal T. cruzi strain.

15-deoxy-Δ12,14 -prostaglandin J2 reduces recruitment of bone marrow-derived monocyte/macrophages in chronic liver injury in mice

15-Deoxy-Δ(12,14) -Prostaglandin J(2) (15d-PGJ(2) ), a natural peroxisome proliferator-activated receptor gamma (PPAR-γ) ligand, has been implicated as a new antiinflammatory compound with possible clinical applications. Based on this concept, this study was designed to evaluate the effects of 15d-PGJ(2) on bone marrow-derived monocyte/macrophage (BMM) migration, phagocytosis, and cytokine expression after liver injury using mouse models induced by cholestasis or carbon tetrachloride. Mice were lethally irradiated and received bone marrow transplants from enhanced green fluorescent protein transgenic mice. Our results showed that recruitment of BMM was significantly increased during chronic liver injury, and that 15d-PGJ(2) administration reduced BMM, but not neutrophil, dendritic, or T cell migration toward the damaged liver, involving reactive oxygen species generation and independently of PPAR-γ. Moreover, 15d-PGJ(2) inhibited the phagocytic activity of BMM and down-regulated inflammatory cytokine expression in vivo and in vitro. Accordingly, hepatic inflammation and fibrosis were strikingly ameliorated after 15d-PGJ(2) administration.

CONCLUSION

Our findings strongly suggest the antiinflammation and antifibrogenic potential of 15d-PGJ(2) in chronic liver diseases.

15-Deoxy-Δ(12,14)-prostaglandin J(2) attenuates the biological activities of monocyte/macrophage cell lines

Monocytes/macrophages link the innate and adaptive immune systems, and in inflammatory disorders their activation leads to tissue damage. 15-Deoxy-Δ(12,14)-prostaglandin J(2) (15d-PGJ(2)), a natural peroxisome proliferator-activated receptor gamma (PPARγ) ligand, has garnered much interest because it possesses anti-inflammatory properties in a number of experimental models. However, whether it regulates monocytes/macrophage pathophysiology is still unknown. This study was designed to examine the effects of 15d-PGJ(2) on the phagocytosis, proliferation and inflammatory cytokines generation in mouse monocyte/macrophage cell line RAW264.7 and J774A.1 cells upon lipopolysaccharide challenge. Our results showed that 15d-PGJ(2) inhibited the phagocytic activity and cell proliferation in a dose-dependent manner, and suppressed proinflammatory cytokines expression, such as tumor necrosis factor-α, transforming growth factor-β1, interleukin-6, and monocyte chemotactic protein-1. These effects were independent of PPARγ, because PPARγ agonist (troglitazone or ciglitazone) and PPARγ antagonist (GW9662) did not affect these activities mentioned above in cells. Treatment of 15d-PGJ(2) also did not modulate expression and distribution of PPARγ. However, these effects of 15d-PGJ(2) were abrogated by antioxidant N-acetylcysteine. Moreover, treatment of 15d-PGJ(2) induced a significant increase in reactive oxygen species production in RAW264.7 and J774A.1 cells. In conclusion, 15d-PGJ(2) attenuates the biological activities of mouse monocyte/macrophage cell line cells involving oxidative stress, independently of PPARγ. These data further underline the anti-inflammation potential of 15d-PGJ(2).

15d-PGJ2-loaded in nanocapsules enhance the antinociceptive properties into rat temporomandibular hypernociception

AIMS

To verify whether the nanoencapsulation of 15d-PGJ(2) in poly(D,L-lactide-co-glycolide) (PLGA) nanocapsules (15d-PGJ(2)-NC) might potentialize its antinociceptive activity into rats' temporomandibular joint (TMJ).

MAIN METHODS

Transmission electron microscopy (TEM) and atomic force microscopy (AFM) were used to evaluate the morphology and suspension of the PLGA nanocapsules. Rats were pretreated (15 min) with an intra-TMJ injection of unloaded 15d-PGJ(2) or 15d-PGJ(2)-NC at concentrations of 10, 100 or 1000 pg followed by an ipsilateral intra-TMJ injection of 1.5% formalin. The nociceptive behavioral response was observed during 45 min; animals were then sacrificed and the periarticular tissue was removed for IL-1β measurements.

KEY FINDING

TEM and AFM analyses showed that 15d-PGJ(2)-NC is spherical without any aggregates or adhesion confirming that this formulation is a good drug carrier system for 15d-PGJ(2). Pretreatment with 15d-PGJ(2)-NC (100 and 1000 pg/TMJ), but not unloaded 15d-PGJ(2), was found to significantly decrease the release of IL-1β cytokine and the animals' nociceptive behavioral response induced by intra-TMJ injection of formalin.

SIGNIFICANCE

The compound 15d-PGJ(2)-NC might be used as a potential antinociceptive and anti-inflammatory agent to treat temporomandibular disorders in clinical practice.