In vivo liposomal delivery of PPAR?/? dual agonist tesaglitazar in a model of obesity enriches macrophage targeting and limits liver and kidney drug effects.
ABSTRACT: Macrophages are important regulators of obesity-associated inflammation and PPAR? and -? agonism in macrophages has anti-inflammatory effects. In this study, we tested the efficacy with which liposomal delivery could target the PPAR?/? dual agonist tesaglitazar to macrophages while reducing drug action in common sites of drug toxicity: the liver and kidney, and whether tesaglitazar had anti-inflammatory effects in an in vivo model of obesity-associated dysmetabolism.Methods: Male leptin-deficient (ob/ob) mice were administered tesaglitazar or vehicle for one week in a standard oral formulation or encapsulated in liposomes. Following the end of treatment, circulating metabolic parameters were measured and pro-inflammatory adipose tissue macrophage populations were quantified by flow cytometry. Cellular uptake of liposomes in tissues was assessed using immunofluorescence and a broad panel of cell subset markers by flow cytometry. Finally, PPAR?/? gene target expression levels in the liver, kidney, and sorted macrophages were quantified to determine levels of drug targeting to and drug action in these tissues and cells.Results: Administration of a standard oral formulation of tesaglitazar effectively treated symptoms of obesity-associated dysmetabolism and reduced the number of pro-inflammatory adipose tissue macrophages. Macrophages are the major cell type that took up liposomes with many other immune and stromal cell types taking up liposomes to a lesser extent. Liposome delivery of tesaglitazar did not have effects on inflammatory macrophages nor did it improve metabolic parameters to the extent of a standard oral formulation. Liposomal delivery did, however, attenuate effects on liver weight and liver and kidney expression of PPAR? and -? gene targets compared to oral delivery.Conclusions: These findings reveal for the first time that tesaglitazar has anti-inflammatory effects on adipose tissue macrophage populations in vivo. These data also suggest that while nanoparticle delivery reduced off-target effects, yet the lack of tesaglitazar actions in non-targeted cells such (as hepatocytes and adipocytes) and the uptake of drug-loaded liposomes in many other cell types, albeit to a lesser extent, may have impacted overall therapeutic efficacy. This fulsome analysis of cellular uptake of tesaglitazar-loaded liposomes provides important lessons for future studies of liposome drug delivery.
Project description:Leishmaniasis is a parasitic neglected tropical disease and result in a broad spectrum of clinical manifestations, ranging from a single ulceration to a progressive and fatal visceral disease. Comprising a limited and highly toxic therapeutic arsenal, new treatments are urgently needed. Targeting delivery of drugs has been a promising approach for visceral leishmaniasis (VL). Phosphatidylserine-liposomes have demonstrated superior efficacy in VL, targeting intracellular parasites in host cells through macrophage scavenger receptors. In this work, we investigated the in vitro and in vivo efficacy of the antihelminthic drug nitazoxanide in a nanoliposomal formulation against Leishmania (L.) infantum. Physicochemical parameters of liposomes containing nitazoxanide (NTZ-LP) were determined by dynamic light scattering and small angle X-ray scattering. The efficacy of the formulation was verified in an intracellular amastigote model and in an experimental hamster model. Our findings showed that NTZ-LP was able to eliminate the amastigotes inside the host cell with an IC50 value of 16 ?M. NTZ-LP was labelled a fluorescent probe and by spectrofluorimetry, we observed that the infected macrophages internalized similar levels of the drug to the uninfected cells. The confocal microscopy images confirmed the uptake and demonstrated a diffuse distribution of the NTZ-LP in the cytoplasm of Leishmania-infected macrophages, with the vesicles in a closer proximity to the parasites. For the in vivo efficacy, the liposomal NTZ-LP was administrated intraperitoneally to Leishmania-infected hamsters for 10 consecutive days at 2 mg/kg/day. By qPCR we demonstrated a reduction of the parasite burden by 82% and 50% in the liver (p < 0.05) and spleen (p < 0.05), respectively. NTZ (non-liposomal) was administered at 100 mg/kg/day per oral (p.o.) for the same period, but demonstrated no efficacy. This liposomal formulation ensured a targeting delivery of NTZ to the intracellular parasites, resulting in an good efficacy at a low dose in animals, and it may represent a new candidate therapy for VL.
Project description:Peroxisome proliferator-activated receptors (PPARs) are nuclear hormone receptors that act as ligand-activated transcription factors. Although prescribed for dyslipidemia and type-II diabetes, PPAR agonists also possess anti-addictive characteristics. PPAR agonists decrease ethanol consumption and reduce withdrawal severity and susceptibility to stress-induced relapse in rodents. However, the cellular and molecular mechanisms facilitating these properties have yet to be investigated. We tested three PPAR agonists in a continuous access two-bottle choice (2BC) drinking paradigm and found that tesaglitazar (PPAR?/?; 1.5 mg/kg) and fenofibrate (PPAR?; 150 mg/kg) decreased ethanol consumption in male C57BL/6J mice while bezafibrate (PPAR?/?/?; 75 mg/kg) did not. We hypothesized that changes in brain gene expression following fenofibrate and tesaglitazar treatment lead to reduced ethanol drinking. We studied unbiased genomic profiles in areas of the brain known to be important for ethanol dependence, the prefrontal cortex (PFC) and amygdala, and also profiled gene expression in liver. Genomic profiles from the non-effective bezafibrate treatment were used to filter out genes not associated with ethanol consumption. Because PPAR agonists are anti-inflammatory, they would be expected to target microglia and astrocytes. Surprisingly, PPAR agonists produced a strong neuronal signature in mouse brain, and fenofibrate and tesaglitazar (but not bezafibrate) targeted a subset of GABAergic interneurons in the amygdala. Weighted gene co-expression network analysis (WGCNA) revealed co-expression of treatment-significant genes. Functional annotation of these gene networks suggested that PPAR agonists might act via neuropeptide and dopaminergic signaling pathways in the amygdala. Our results reveal gene targets through which PPAR agonists can affect alcohol consumption behavior.
Project description:Like thapsigargin, which is undergoing clinical trials, trilobolide is a natural product with promising anticancer and anti-inflammatory properties. Similar to thapsigargin, it has limited aqueous solubility that strongly reduces its potential medicinal applications. The targeted delivery of hydrophobic drugs can be achieved using liposome-based carriers. Therefore, we designed a traceable liposomal drug delivery system for trilobolide. The fluorescent green-emitting dye BODIPY, cholesterol and trilobolide were used to create construct 6. The liposomes were composed of dipalmitoyl-3-trimethylammoniumpropane and phosphatidylethanolamine. The whole system was characterized by atomic force microscopy, the average size of the liposomes was 150 nm in width and 30 nm in height. We evaluated the biological activity of construct 6 and its liposomal formulation, both of which showed immunomodulatory properties in primary rat macrophages. The uptake and intracellular distribution of construct 6 and its liposomal formulation was monitored by means of live-cell fluorescence microscopy in two cancer cell lines. The encapsulation of construct 6 into the liposomes improved the drug distribution in cancer cells and was followed by cell death. This new liposomal trilobolide derivative not only retains the biological properties of pure trilobolide, but also enhances the bioavailability, and thus has potential for the use in theranostic applications.
Project description:Targeted nanoparticle delivery is a promising strategy for increasing efficacy and limiting side effects of therapeutics. When designing a targeted liposomal formulation, the in vivo biodistribution of the particles must be characterized to determine the value of the targeting approach. Peroxisome proliferator-activated receptor (PPAR) agonists effectively treat metabolic syndrome by decreasing dyslipidemia and insulin resistance but side effects have limited their use, making them a class of compounds that could benefit from targeted liposomal delivery. The adipose targeting sequence peptide (ATS) could fit this role, as it has been shown to bind to adipose tissue endothelium and induce weight loss when delivered conjugated to a pro-apoptotic peptide. To date, however, a full assessment of ATS in vivo biodistribution has not been reported, leaving important unanswered questions regarding the exact mechanisms whereby ATS targeting enhances therapeutic efficacy. We designed this study to evaluate the biodistribution of ATS-conjugated liposomes loaded with the PPAR?/? dual agonist tesaglitazar in leptin-deficient ob/ob mice. The ATS-liposome biodistribution in adipose tissue and other organs was examined at the cellular and tissue level using microscopy, flow cytometry, and fluorescent molecular tomography. Changes in metabolic parameters and gene expression were measured by target and off-target tissue responses to the treatment. Unexpectedly, ATS targeting did not increase liposomal uptake in adipose relative to other tissues, but did increase uptake in the kidneys. Targeting also did not significantly alter metabolic parameters. Analysis of the liposome cellular distribution in the stromal vascular fraction with flow cytometry revealed high uptake by multiple cell types. Our findings highlight the need for thorough study of in vivo biodistribution when evaluating a targeted therapy.
Project description:Despite the wide-spread use of liposomal drug delivery systems, application of these systems for oral purposes is limited due to their large-scale formulation and storage issues. Proliposomes are one of the formulation approaches for achieving solid powders that readily form liposomes upon hydration. In this work, we investigated a dry powder formulation of a model low-soluble drug with phospholipids loaded in porous functionalized calcium carbonate microparticles. We characterized the liposome formation under conditions that mimic the different gastrointestinal stages and studied the factors that influence the dissolution rate of the model drug. The liposomes that formed upon direct contact with the simulated gastric environment had a capacity to directly encapsulate 25% of the drug in situ. The emerged liposomes allowed complete dissolution of the drug within 15 min. We identified a negative correlation between the phospholipid content and the rate of water uptake. This correlation corroborated the results obtained for the rate of dissolution and liposome encapsulation efficiency. This approach allows for the development of solid proliposomal dosage formulations, which can be scaled up with regular processes.
Project description:Palmitoleic acid (POA, 16:1n-7) is a lipokine that has potential nutraceutical use to treat non-alcoholic fatty liver disease. We tested the effects of POA supplementation (daily oral gavage, 300 mg/Kg, 15 days) on murine liver inflammation induced by a high fat diet (HFD, 59% fat, 12 weeks). In HFD-fed mice, POA supplementation reduced serum insulin and improved insulin tolerance compared with oleic acid (OA, 300 mg/Kg). The livers of POA-treated mice exhibited less steatosis and inflammation than those of OA-treated mice with lower inflammatory cytokine levels and reduced toll-like receptor 4 protein content. The anti-inflammatory effects of POA in the liver were accompanied by a reduction in liver macrophages (LM, CD11c+; F4/80+; CD86+), an effect that could be triggered by peroxisome proliferator activated receptor (PPAR)-?, a lipogenic transcription factor upregulated in livers of POA-treated mice. We also used HFD-fed mice with selective deletion of PPAR-? in myeloid cells (PPAR-? KOLyzCre+) to test whether the beneficial anti-inflammatory effects of POA are dependent on macrophages PPAR-?. POA-mediated improvement of insulin tolerance was tightly dependent on myeloid PPAR-?, while POA anti-inflammatory actions including the reduction in liver inflammatory cytokines were preserved in mice bearing myeloid cells deficient in PPAR-?. This overlapped with increased CD206+ (M2a) cells and downregulation of CD86+ and CD11c+ liver macrophages. Moreover, POA supplementation increased hepatic AMPK activity and decreased expression of the fatty acid binding scavenger receptor, CD36. We conclude that POA controls liver inflammation triggered by fat accumulation through induction of M2a macrophages independently of myeloid cell PPAR-?.
Project description:Peroxisome proliferator-activated receptors (PPARs) are nuclear hormone receptors that act as ligand-activated transcription factors. Although prescribed for dyslipidemia and type-II diabetes, PPAR agonists have demonstrated therapeutic properties for several brain disorders, including alcohol dependence. PPAR agonists decrease ethanol consumption and reduce withdrawal severity and susceptibility to stress-induced relapse in rodents. However, the cellular and molecular mechanisms facilitating these properties have yet to be investigated and little is known about their effects in the brain. We tested three PPAR agonists in a continuous access two-bottle choice (2BC) drinking paradigm and found that tesaglitazar and fenofibrate decreased ethanol consumption in male C57BL/6J mice while bezafibrate did not. Hypothesizing that fenofibrate and tesaglitazar are causing brain gene expression changes that precipitate the reduction in ethanol drinking, we gave daily oral injections of fenofibrate, tesaglitazar and bezafibrate to mice for eight consecutive days and collected liver, prefrontal cortex and amygdala 24 hours after last injection. RNA was isolated and purified using MagMAX-96 Total RNA Isolation Kit. Biotinylated, amplified cRNA was generated using Illumina TotalPrep RNA Amplification Kit and hybridized to Illumina MouseWG-6 v2.0 Expression microarrays. Mice were divided into four groups (N=10 per group): fenofibrate, tesaglitazar, bezafibrate and saline. See summary and protocols for details.
Project description:Peroxisome proliferator activated receptors (PPARs) are nuclear hormone receptors that act as transcription factors in response to endogenous lipid messengers. The fibrates and thiazolidinediones are synthetic PPAR agonists used clinically to treat dyslipidemia and Type 2 Diabetes Mellitus, respectively, but also improve symptoms of several other diseases. Transposable elements (TEs), repetitive sequences in mammalian genomes, are implicated in many of the same conditions for which PPAR agonists are therapeutic, including neurodegeneration, schizophrenia, and drug addiction. We tested the hypothesis that there is a link between actions of PPAR agonists and TE expression. We developed an innovative application of microarray data by mapping Illumina mouse WG-6 microarray probes to areas of the mouse genome that contain TEs. Using this information, we assessed the effects of systemic administration of three PPAR agonists with different PPAR subtype selectivity: fenofibrate, tesaglitazar, and bezafibrate, on TE probe expression in mouse brain [prefrontal cortex (PFC) and amygdala] and liver. We found that fenofibrate, and bezafibrate to a lesser extent, up-regulated probes mapped to retrotransposons: Short-Interspersed Elements (SINEs) and Long-Interspersed Elements (LINEs), in the PFC. Conversely, all PPAR agonists down-regulated LINEs and tesaglitazar and bezafibrate also down-regulated SINEs in liver. We built gene coexpression networks that partitioned the diverse transcriptional response to PPAR agonists into groups of probes with highly correlated expression patterns (modules). Most of the differentially expressed retrotransposons were within the same module, suggesting coordinated regulation of their expression, possibly by PPAR signaling. One TE module was conserved across tissues and was enriched with genes whose products participate in epigenetic regulation, suggesting that PPAR agonists affect TE expression via epigenetic mechanisms. Other enriched functional categories included phenotypes related to embryonic development and learning and memory, suggesting functional links between these biological processes and TE expression. In summary, these findings suggest mechanistic relationships between retrotransposons and PPAR agonists and provide a basis for future exploration of their functional roles in brain and liver.
Project description:OBJECTIVE:PPAR?/? dual agonists have been in clinical development for the treatment of metabolic diseases including type 2 diabetes and dyslipidemia. However, severe adverse side effects led to complications in clinical trials. As most of the beneficial effects rely on the compound activity in adipocytes, the selective targeting of this cell type is a cutting-edge strategy to develop safe anti-diabetic drugs. The goal of this study was to strengthen the adipocyte-specific uptake of the PPAR?/? agonist tesaglitazar via NPY1R-mediated internalization. METHODS:NPY1R-preferring peptide tesaglitazar-[F7, P34]-NPY (tesa-NPY) was synthesized by a combination of automated SPPS and manual couplings. Following molecular and functional analyses for proof of concept, cell culture experiments were conducted to monitor the effects on adipogenesis. Mice treated with peptide drug conjugates or vehicle either by gavage or intraperitoneal injection were characterized phenotypically and metabolically. Histological analysis and transcriptional profiling of the adipose tissue were performed. RESULTS:In vitro studies revealed that the tesaglitazar-[F7, P34]-NPY conjugate selectively activates PPAR? in NPY1R-expressing cells and enhances adipocyte differentiation and adiponectin expression in adipocyte precursor cells. In vivo studies using db/db mice demonstrated that the anti-diabetic activity of the peptide conjugate is as efficient as that of systemically administered tesaglitazar. Additionally, tesa-NPY induces adipocyte differentiation in vivo. CONCLUSIONS:The use of the tesaglitazar-[F7, P34]-NPY conjugate is a promising strategy to apply the beneficial PPAR?/? effects in adipocytes while potentially omitting adverse effects in other tissues.
Project description:OBJECTIVE:Peroxisome proliferator-activated receptors (PPARs) are key transcription factors that regulate adipose development and function, and the conversion of white into brown-like adipocytes. Here we investigated whether PPAR? and PPAR? activation synergize to induce the browning of white fat. METHODS:A selection of PPAR activators was tested for their ability to induce the browning of both mouse and human white adipocytes in vitro, and in vivo in lean and obese mice. RESULTS:All dual PPAR?/? activators tested robustly increased uncoupling protein 1 (Ucp1) expression in both mouse and human adipocytes in vitro, with tesaglitazar leading to the largest Ucp1 induction. Importantly, dual PPAR?/? activator tesaglitazar strongly induced browning of white fat in vivo in both lean and obese male mice at thermoneutrality, greatly exceeding the increase in Ucp1 observed with the selective PPAR? activator rosiglitazone. While selective PPAR? activation was sufficient for the conversion of white into brown-like adipocytes in vitro, dual PPAR?/? activation was superior to selective PPAR? activation at inducing white fat browning in vivo. Mechanistically, the superiority of dual PPAR?/? activators is mediated at least in part via a PPAR?-driven increase in fibroblast growth factor 21 (FGF21). Combined treatment with rosiglitazone and FGF21 resulted in a synergistic increase in Ucp1 mRNA levels both in vitro and in vivo. Tesaglitazar-induced browning was associated with increased energy expenditure, enhanced insulin sensitivity, reduced liver steatosis, and an overall improved metabolic profile compared to rosiglitazone and vehicle control groups. CONCLUSIONS:PPAR? and PPAR? synergize to induce robust browning of white fat in vivo, via PPAR? activation in adipose, and PPAR?-mediated increase in FGF21.