Deficiency of ribosomal protein S26, which is mutated in a subset of patients with Diamond Blackfan anemia, impairs erythroid differentiation.

Introduction: Diamond Blackfan anemia (DBA) is a rare congenital disease characterized by defective maturation of the erythroid progenitors in the bone marrow, for which treatment involves steroids, chronic transfusions, or hematopoietic stem cells transplantation. Diamond Blackfan anemia is caused by defective ribosome biogenesis due to heterozygous pathogenic variants in one of 19 ribosomal protein (RP) genes. The decreased number of functional ribosomes leads to the activation of pro-apoptotic pathways and to the reduced translation of key genes for erythropoiesis. Results and discussion: Here we characterized the phenotype of RPS26-deficiency in a cell line derived from human umbilical cord blood erythroid progenitors (HUDEP-1 cells). This model recapitulates cellular hallmarks of Diamond Blackfan anemia including: imbalanced production of ribosomal RNAs, upregulation of pro-apoptotic genes and reduced viability, and shows increased levels of intracellular calcium. Evaluation of the expression of erythroid markers revealed the impairment of erythroid differentiation in RPS26-silenced cells compared to control cells. Conclusions: In conclusion, for the first time we assessed the effect of RPS26 deficiency in a human erythroid progenitor cell line and demonstrated that these cells can be used as a scalable model system to study aspects of DBA pathophysiology that have been refractory to detailed investigation because of the paucity of specific cell types affected in this disorder.

The Complex Journey of the Calcium Regulation Downstream of TAS2R Activation.

Bitter taste receptors (TAS2Rs) have recently arisen as a potential drug target for asthma due to their localization in airway cells. These receptors are expressed in all cell types of the respiratory system comprising epithelial, smooth muscle and immune cells; however, the expression pattern of the subtypes is different in each cell type and, accordingly, so is their role, for example, anti-inflammatory or bronchodilator. The most challenging aspect in studying TAS2Rs has been the identification of the downstream signaling cascades. Indeed, TAS2R activation leads to canonical IP3-dependent calcium release from the ER, but, alongside, there are other mechanisms that differ according to the histological localization. In this review, we summarize the current knowledge on the cytosolic calcium modulation downstream of TAS2R activation in the epithelial, smooth muscle and immune cells of the airway system.

Regenerative Potential of A Bovine ECM-Derived Hydrogel for Biomedical Applications.

Recent advancements in regenerative medicine have enhanced the development of biomaterials as multi-functional dressings, capable of accelerating wound healing and addressing the challenge of chronic wounds. Hydrogels obtained from decellularized tissues have a complex composition, comparable to the native extracellular environment, showing highly interesting characteristics for wound healing applications. In this study, a bovine pericardium decellularized extracellular matrix (dECM) hydrogel was characterized in terms of macromolecules content, and its immunomodulatory, angiogenic and wound healing potential has been evaluated. The polarization profile of human monocytes-derived macrophages seeded on dECM hydrogel was assessed by RT-qPCR. Angiogenic markers expression has been evaluated by Western blot and antibody array on cell lysates derived from endothelial cells cultured on dECM hydrogel, and a murine in vivo model of hindlimb ischemia was used to evaluate the angiogenic potential. Fibroblast migration was assessed by a transwell migration assay, and an in vivo murine wound healing model treated with dECM hydrogels was also used. The results showed a complex composition, of which the major component is collagen type I. The dECM hydrogel is biocompatible, able to drive M2 phenotype polarization, stimulate the expression of angiogenic markers in vitro, and prevent loss of functionality in hindlimb ischemia model. Furthermore, it drives fibroblast migration and shows ability to facilitate wound closure in vivo, demonstrating its great potential for regenerative applications.

Characterization of a functional Ca2+ toolkit in urine-derived stem cells and derived skeletal muscle cells.

Muscular diseases are characterized by a wide genetic diversity and the Ca2+-signalling machinery is often perturbed. Its characterization is therefore pivotal and requires appropriate cellular models. Muscle biopsies are the best approach but are invasive for the patient and difficult to justify if the biopsy is not for diagnostic purposes. To circumvent this, interest is mounting in urine-derived stem cells that can be differentiated into skeletal muscle cells. In the present study, we isolated stem cells from urine (USC) samples of healthy donors and differentiated them by MyoD lentiviral vector transduction into skeletal muscle cells (USC-SkMC). As expected, USCs and USC-SkMCs are characterized by a radically different pattern of expression of stem and skeletal muscle markers. Characterization of cells in the present manuscript focused on Ca2+-signalling. Undifferentiated and differentiated cells differed in the expression of key proteins involved in Ca2+-homeostasis and also displayed different Ca2+-responses to external stimuli, confirming that during differentiation there was a transition from a non-excitable to an excitable phenotype. In USCs, the main mechanism of calcium entry was IP3 dependent, suggesting a major involvement of receptor-operated Ca2+ entry. Indeed, U-73122 (a PLC inhibitor) significantly inhibited the Ca2+increase triggered by ATP both in calcium and calcium-free conditions. In USC-SkMCs both store- and receptor-operated calcium entry were active. Furthermore, a caffeine challenge led to Ca2+ release both in the presence or absence of extracellular calcium, which was inhibited by ryanodine, suggesting the presence and functionality of ryanodine receptors in USC-SkMCs. Lastly, the voltage-operated calcium channels are operative in USC-SkMCs, unlike in USCs, since stimulation with high concentration of KCl induced a significant calcium transient, partially reversed by verapamil. Our data therefore support the use of skeletal muscle cells derived from USCs as an easily amenable tool to investigate Ca2+-homeostasis, in particular in those (neuro)muscular diseases that lack valid alternative models.

Paracrine Shear-Stress-Dependent Signaling from Endothelial Cells Affects Downstream Endothelial Function and Inflammation.

Cardiovascular diseases (CVDs), mainly ischemic heart disease (IHD) and stroke, are the leading cause of global mortality and major contributors to disability worldwide. Despite their heterogeneity, almost all CVDs share a common feature: the endothelial dysfunction. This is defined as a loss of functionality in terms of anti-inflammatory, anti-thrombotic and vasodilatory abilities of endothelial cells (ECs). Endothelial function is greatly ensured by the mechanotransduction of shear forces, namely, endothelial wall shear stress (WSS). Low WSS is associated with endothelial dysfunction, representing the primary cause of atherosclerotic plaque formation and an important factor in plaque progression and remodeling. In this work, the role of factors released by ECs subjected to different magnitudes of shear stress driving the functionality of downstream endothelium has been evaluated. By means of a microfluidic system, HUVEC monolayers have been subjected to shear stress and the conditioned media collected to be used for the subsequent static culture. The results demonstrate that conditioned media retrieved from low shear stress experimental conditions (LSS-CM) induce the downregulation of endothelial nitric oxide synthase (eNOS) expression while upregulating peripheral blood mononuclear cell (PBMC) adhesion by means of higher levels of adhesion molecules such as E-selectin and ICAM-1. Moreover, LSS-CM demonstrated a significant angiogenic ability comparable to the inflammatory control media (TNFα-CM); thus, it is likely related to tissue suffering. We can therefore suggest that ECs stimulated at low shear stress (LSS) magnitudes are possibly involved in the paracrine induction of peripheral endothelial dysfunction, opening interesting insights into the pathogenetic mechanisms of coronary microvascular dysfunction.

Polylysine Enriched Matrices: A Promising Approach for Vascular Grafts.

Cardiovascular diseases represent the leading cause of death in developed countries. Modern surgical methods show poor efficiency in the substitution of small-diameter arteries (<6 mm). Due to the difference in mechanical properties between the native artery and the substitute, the behavior of the vessel wall is a major cause of inefficient substitutions. The use of decellularized scaffolds has shown optimal prospects in different applications for regenerative medicine. The purpose of this work was to obtain polylysine-enriched vascular substitutes, derived from decellularized porcine femoral and carotid arteries. Polylysine acts as a matrix cross-linker, increasing the mechanical resistance of the scaffold with respect to decellularized vessels, without altering the native biocompatibility and hemocompatibility properties. The biological characterization showed an excellent biocompatibility, while mechanical tests displayed that the Young's modulus of the polylysine-enriched matrix was comparable to native vessel. Burst pressure test demonstrated strengthening of the polylysine-enriched matrix, which can resist to higher pressures with respect to native vessel. Mechanical analyses also show that polylysine-enriched vessels presented minimal degradation compared to native. Concerning hemocompatibility, the performed analyses show that polylysine-enriched matrices increase coagulation time, with respect to commercial Dacron vascular substitutes. Based on these findings, polylysine-enriched decellularized vessels resulted in a promising approach for vascular substitution.

Structure activity relationship studies on Amb639752: toward the identification of a common pharmacophoric structure for DGKα inhibitors.

A series of analogues of Amb639752, a novel diacylglycerol kinase (DGK) inhibitor recently discovered by us via virtual screening, have been tested. The compounds were evaluated as DGK inhibitors on α, θ, and ζ isoforms, and as antagonists on serotonin receptors. From these assays emerged two novel compounds, namely 11 and 20, which with an IC50 respectively of 1.6 and 1.8 µM are the most potent inhibitors of DGKα discovered to date. Both compounds demonstrated the ability to restore apoptosis in a cellular model of X-linked lymphoproliferative disease as well as the capacity to reduce the migration of cancer cells, suggesting their potential utility in preventing metastasis. Finally, relying on experimental biological data, molecular modelling studies allow us to set a three-point pharmacophore model for DGK inhibitors.

Comparison of anti-inflammatory mechanisms between doxofylline and theophylline in human monocytes.

BACKGROUND: Methylxanthines are important pharmacological agents in the treatment of asthma and of chronic obstructive pulmonary diseases. The present study was designed to compare the ability of doxofylline and theophylline to modulate inflammatory pathways in human monocytes. METHODS: Monocytes isolated from healthy anonymous human buffy coats were treated with doxofylline or theophylline in the presence of phorbol 12-myristate 13-acetate (PMA) or lipopolysaccharide (LPS), and their phenotype, the oxidative burst, cytokine expression and release, cAMP production, and protein kinase C (PKC) activity were evaluated. RESULTS: Doxofylline and theophylline did not have overlapping effects on human monocytes. While sharing some common characteristics, they differed significantly in their selectivity. Theophylline affected LPS- above PMA-induced cellular responsivity, while doxofylline behaved in the opposite manner. Furthermore, when testing PKC activity, we found an inhibitory effect of doxofylline but not of theophylline, at equimolar doses. CONCLUSIONS: In conclusion, our data support the growing hypothesis that doxofylline does not have a superimposable mechanism of action compared to theophylline, and this may both explain some differences in the risk/benefit ratio and may direct studies to tailor therapy for patients.

Identification of a novel DGKα inhibitor for XLP-1 therapy by virtual screening.

As part of an effort to identify druggable diacylglycerol kinase alpha (DGKα) inhibitors, we used an in-silico approach based on chemical homology with the two commercially available DGKα inhibitors R59022 and R59949. Ritanserin and compound AMB639752 emerged from the screening of 127 compounds, showing an inhibitory activity superior to the two commercial inhibitors, being furthermore specific for the alpha isoform of diacylglycerol kinase. Interestingly, AMB639752 was also devoid of serotoninergic activity. The ability of both ritanserin and AMB639752, by inhibiting DGKα in intact cells, to restore restimulation induced cell death (RICD) in SAP deficient lymphocytes was also tested. Both compounds restored RICD at concentrations lower than the two previously available inhibitors, indicating their potential use for the treatment of X-linked lymphoproliferative disease 1 (XLP-1), a rare genetic disorder in which DGKα activity is deregulated.

Effect of Cyclic Stretch on Vascular Endothelial Cells and Abdominal Aortic Aneurysm (AAA): Role in the Inflammatory Response.

Abdominal aortic aneurysm (AAA) is a focal dilatation of the aorta, caused by both genetic and environmental factors. Although vascular endothelium plays a key role in AAA progression, the biological mechanisms underlying the mechanical stress involvement are only partially understood. In this study, we developed an in vitro model to characterize the role of mechanical stress as a potential trigger of endothelial deregulation in terms of inflammatory response bridging between endothelial cells (ECs), inflammatory cells, and matrix remodeling. In AAA patients, data revealed different degrees of calcification, inversely correlated with wall stretching and also with inflammation and extracellular matrix degradation. In order to study the role of mechanical stimulation, endothelial cell line (EA.hy926) has been cultured in healthy (10% strain) and pathological (5% strain) dynamic conditions using a bioreactor. In presence of tumor necrosis factor alpha (TNF-α), high levels of matrix metalloproteinase-9 (MMP-9) expression and inflammation are obtained, while mechanical stimulation significantly counteracts the TNF-α effects. Moreover, physiological deformation also plays a significant role in the control of the oxidative stress. Overall our findings indicate that, due to wall calcification, in AAA there is a significant change in terms of decreased wall stretching.

An Artemisia-derived natural product-based fluorescent probe for the bitter taste receptor hTAS2R38.

The discovery of taste receptors hTAS2Rs expression in extra oral tissue, especially in the gastrointestinal tract and in the respiratory system, has endowed bitter receptors of functionalities that exceed the simple perception of taste and flavour. In particular, stimulation of hTAS2Rs by bitter agents in the airway smooth muscle triggers bronchodilation of possible pharmacological relevance. To study the receptor localization in pulmonary smooth muscle cells and to investigate their biological response to hTAS2R38 activation, we have developed a fluorescent probe for hTAS2R38 starting from the sesquiterpene lactone costunolide, available in multigram amounts from Artemisia umbelliformis Lam. The N-methylanthranilate-containing probe demonstrated a very low cytotoxicity compared to the natural product toward human airway smooth muscle cells and epithelial bronchial cells, but fully retained its binding to hTAS2R38, making it possible the fluorescent detection of cells expressing this bitter receptor.

Cannabis Phenolics and their Bioactivities.

BACKGROUND: Although Cannabis sativa L. is one of the most versatile plant species with multipurpose use both as medical, alimentary source and as psychoactive abuse, its biomedical relevance focused the attention on major cannabinoids. Phytochemical characterization of cannabis highlights the presence of various non-cannabinoids constituents including flavonoids, spiroindans, dihyrostilbenes, dihydrophenanthrenes, lignanamides, steroids and alkaloids. This review aims to identify polyphenols present in this plant, their biosynthesis, their bioactivities and their synthesis, when this occurred. METHODS: We undertook a systematic research focused on bibliographic databases including all noncannabinoids phenolics in various C. sativa strains from their isolation, structural elucidation, their biological activity to their synthesis. RESULT: Nevertheless, attention has so far been focused only on cannabinoids (more than one hundred isolated), cannabis is a complex plant able to produce more than 480 chemical entities that represent almost all of the different biogenetic classes. Regarding phenolic compounds, the plant biosynthesises a plethora of unique non-cannabinoids second metabolites, such as prenylated flavonoids, stilbenoids derivatives and lignanammides. CONCLUSION: Cannabis is a plant with high pharmacological and nutrition values, its potentialities and applications are not only circumscribed to cannabinoids biological activities, but also defined by noncannabinoid compounds. The combination of other cannabinoids together with noncannabinoid components could enhance the beneficial effects of THC and could reduce undesirable side effects.

Vortioxetine exerts anti-inflammatory and immunomodulatory effects on human monocytes/macrophages.

BACKGROUND AND PURPOSE: A crosstalk between the immune system and depression has been postulated, with monocytes/macrophages and cytokines having a key role in this interaction. In this study, we examined whether vortioxetine, a multimodal anti-depressive drug, was endowed with anti-inflammatory and antioxidative activity, leading to immunomodulatory effects on human monocytes and macrophages. EXPERIMENTAL APPROACH: Human monocytes were isolated from buffy coats and used as such or differentiated into M1 and M2 macrophages. Cells were treated with vortioxetine before or after differentiation, and their responsiveness was evaluated. This included oxy-radical and TNFα production, TNFα and PPARγ gene expression and NF-κB translocation. KEY RESULTS: Vortioxetine significantly reduced the PMA-induced oxidative burst in monocytes and in macrophages (M1 and M2), causing a concomitant shift of macrophages from the M1 to the M2 phenotype, demonstrated by a significant decrease in the expression of the surface marker CD86 and an increase in CD206. Moreover, treatment of monocytes with vortioxetine rendered macrophages derived from this population less sensitive to PMA, as it reduced the oxidative burst, NF-kB translocation, TNFα release and expression while inducing PPARγ gene expression. FACS analysis showed a significant decrease in the CD14+ /CD16+ /CD86+ M1 population. CONCLUSIONS AND IMPLICATIONS: These results demonstrate that in human monocytes/macrophages, vortioxetine has antioxidant activity and anti-inflammatory effects driving the polarization of macrophages towards their alternative phenotype. These findings suggest that vortioxetine, alongside its antidepressive effect, may have immunomodulatory properties.

Relation among anti-rheumatic drug therapy, CD14(+)CD16(+) blood monocytes and disease activity markers (DAS28 and US7 scores) in rheumatoid arthritis: A pilot study.

Circulating human monocytes, a functionally and phenotypically heterogeneous population, are emerging as fundamental cell types in rheumatoid arthritis (RA). The aim of this pilot study was to assess the correlation, if any, among anti-rheumatic drug therapy, circulating CD14(+)CD16(+) monocytes and validated clinical scales (e.g., DAS28 score and ultrasonography US7 score) of disease severity in RA. Thirty consecutive RA patients, either naïve or under disease-modifying anti-rheumatic drugs (DMARDs) or biological therapy, and 10 age-matched healthy volunteers, were enrolled. Monocytes were prepared from heparinized blood samples; surface expression of CD14 and CD16 was determined by flow cytometry. RA patients presented a significantly higher percentage of CD14(+)CD16(+) monocytes, as compared to healthy subjects. There was a good correlation between DAS28 clinical score and the ultrasound composite score US7 (r=0.66), as well as between both scores and the percentage of CD14(+)CD16(+) monocytes (r=0.43 and 0.47, respectively). Naïve RA patients had the highest expression (19.2±3.2%) of CD14(+)CD16(+) monocytes and elevated DAS28 score; patients on DMARDs presented a 7-fold increased expression of CD14(+)CD16(+) monocytes, relatively to healthy volunteers (2.1±1.4%), and an intermediate disease severity. The RA patients treated with biological therapy had a low percentage of CD14(+)CD16(+) monocytes (5.1±3.6%; p<0.01 vs naïve and DMARDs groups), similar to the one detected in healthy controls, and reduced US7 and DAS28 scores. Interestingly, for the same DAS28 score, monocytes isolated from RA patients on biological therapy had a lower CD16 expression than patients on DMARDs. Therefore, CD14(+)CD16(+) circulating blood monocytes may represent an appropriate biomarker to assess RA disease activity along with DAS28 and US7 scores. Together, these three parameters may represent a better indicator for evaluating therapy efficacy.

Modulation of human monocyte/macrophage activity by tocilizumab, abatacept and etanercept: An in vitro study.

Tocilizumab, etanercept and abatacept are biological drugs used in the therapy of Rheumatoid Arthritis (RA). Their mechanism of action is well documented but their direct effects on human monocytes/macrophages have not been fully investigated. The objective of this study was to evaluate in vitro the influence of these drugs on monocytes/macrophages from healthy volunteers. Human monocytes were isolated from healthy anonymous volunteers and cultured as such or differentiated to monocyte-derived macrophages (MDMs). The effect of tocilizumab, etanercept and abatacept (at concentrations similar to those in plasma of patients) on superoxide anion production, matrix metalloproteinase-9 (MMP-9) gene expression and activity, Peroxisome Proliferator-Activated Receptor (PPAR)γ expression and cell phenotype was evaluated. Exposure of monocytes/macrophages to tocilizumab, etanercept or abatacept resulted in a significant decrease of the PMA-induced superoxide anion production. Interestingly, the expression of PPARγ was significantly increased only by tocilizumab, while etanercept was the only one able to significantly reduce MMP-9 gene expression and inhibit the LPS-induced MMP-9 activity in monocytes. When etanercept and abatacept were added to the differentiating medium, both significantly reduced the amount of CD206(+)MDM. This study demonstrates that etanercept, abatacept and tocilizumab affect differently human monocytes/macrophages. In particular, the IL-6 antagonist tocilizumab seems to be more effective in inducing an anti-inflammatory phenotype of monocytes/macrophages compared to etanercept and abatacept, also in light of the up-regulation of PPARγ whose anti-inflammatory effects are well recognised.

Neurokinin (NK)-1 receptor expression in monocytes from bipolar disorder patients: a pilot study.

BACKGROUND: Neurokinin 1 receptors (NK-1R) have been involved in several psychiatric disorders including major depression, but less is known for bipolar disorder (BD). METHOD: We compared NK-1R expression and Substance P (SP) ability to induce NF-κB activation in monocytes from BD patients and healthy donors (HD), also looking for the effects of tobacco smoke. After informed written consent, 20 euthymic BD patients, either bipolar type 1 (BDI) or type 2 (BDII), and 14 age-matched healthy donors (HD) were enrolled. NK-1R expression in monocytes was evaluated by Western blot and expressed as the ratio between NK-1R and Na(+)/K(+)-ATPase protein expressions. NF-κB activation was assessed by measuring the nuclear content of the p50 subunit (ELISA kit). RESULTS: NK-1R expression was significantly reduced (P<0.001) in monocytes from BD patients as compared to HD, with no major differences between BDI and BDII patients. Tobacco smoke enhanced NK-1R expression in HD, but not in BD patients. Un-stimulated monocytes from BD patients presented a constitutively higher (P<0.05) content of nuclear p50 subunit as compared to HD. SP and an NK-1R agonist induced NF-κB activation, with a higher effect in HD: this effect was receptor-mediated as it was abrogated by an NK-1R antagonist. LIMITATIONS: As a pilot study enrolling 20 BD patients, an obvious limitation is the sample size. CONCLUSIONS: Our results show the existence of a relevant alteration in NK-1R expression in BD patients and further suggest SP involvement in BD, so improving our understanding of the underlying mechanisms of this disease.

Characterization of the anti-inflammatory properties of NCX 429, a dual-acting compound releasing nitric oxide and naproxen.

AIMS: Cyclooxygenase (COX)-inhibiting nitric oxide donors (CINODs) are a new class of drugs that structurally combine a COX inhibitor with a nitric oxide (NO) donating moiety. This combination reduces potential toxicity of the non-steroidal anti-inflammatory drugs (NSAIDs) whilst maintaining the analgesic and anti-inflammatory effects. The present study was undertaken to investigate the anti-inflammatory effects of NCX 429, a naproxen-based CINOD, and to assess the additional properties of NO donation beyond those related to naproxen. MAIN METHODS: We evaluated the in vitro effects of NCX 429 on oxy-radical production, phagocytosis, cytokine release, MMP-9, PPARγ expression and NF-κB activation in human monocytes/MDM and compared to naproxen. Moreover, we compared the in vivo efficacy of NCX 429 and naproxen in a murine model of peritonitis. KEY FINDINGS: In all the experiments performed in vitro, NCX 429 reduced the inflammatory responses with equal or higher efficacy compared to naproxen. Moreover, in in vivo experiments, NCX 429, at the lowest dose tested, was able to significantly inhibit cell influx in response to IL-1ß administration although naproxen was found to be more potent than NCX 429 at reducing PGE2 in inflammatory exudates. SIGNIFICANCE: These results demonstrate that both in vitro and in vivo--in a murine model of peritonitis--NCX 429 elicits significant anti-inflammatory activity, beyond the simple COX inhibition or pure NO release. Therefore, NO donation along with COX inhibition may represent a strategy for investigating inflammatory diseases in which pain and function are not fully resolved by analgesics/anti-inflammatory drugs.

Recurrent major depressive disorder: Imbalance of neurokinin (NK)-1 and NK-2 receptor expression in monocytes.

Increasing evidence suggests that tachykinins are involved in the control of different pathological conditions, including psychiatric disorders. In this study we evaluated the expression of NK(1) and NK(2) receptors (NK-1R and NK-2R), as well as the effects of substance P (SP) and neurokinin A (NKA), in monocytes isolated from 15 healthy subjects and 15 patients with recurrent major depressive disorder (RMDD), under stable antidepressant therapy. NK-1R expression in monocytes from RMDD patients was significantly decreased as compared to healthy subjects, whereas NK-2R expression was markedly increased. Both NK-1R and NK-2R expression correlated with HAM-D, but not HAM-A, score. SP, NKA and selective NK-1R and NK-2R agonists stimulated TNF-α release in monocytes of both groups, with a significant higher effect observed in RMDD. Moreover they induced NF-κB activation, which was reversed by selective NK-1R and NK-2R antagonists, so demonstrating that it was receptor-mediated. The occurrence of a profound alteration in NK receptor expression in RMDD is a novel finding that suggests NK-1R and NK-2R pathways as possible relevant players in major depressive disorder, so improving our understanding of the complex pathogenesis of the disease.

Peroxisome proliferator-activated receptor-gamma expression in monocytes/macrophages from rheumatoid arthritis patients: relation to disease activity and therapy efficacy--a pilot study.

OBJECTIVES: Peroxisome proliferator-activated receptor-gamma (PPARγ) is expressed by different cell types in the joints and plays a relevant anti-inflammatory role in various diseases. This pilot study aimed to evaluate PPARγ expression in monocytes/macrophages isolated from RA patients as compared with healthy subjects, the relationships between PPARγ expression, MMP-9 activity and disease, and the influence of therapy with anti-rheumatic drugs on these parameters. METHODS: Thirty RA patients of both sexes (treated with CSs and MTX, mainly) and 15 healthy volunteers were enrolled in this study. Disease severity was evaluated by the 28-joint disease activity score (DAS-28). Monocytes and monocyte-derived macrophages (MDMs) were isolated by standard procedures. PPARγ protein and mRNA expression were assessed by immunoblotting and real-time PCR, respectively; MMP-9 activity was determined by gelatin zymography. Moreover, we checked the ability of 15-deoxy-Δ(12,14)-prostaglandin J(2) (15d-PGJ, a PPARγ agonist), MTX and methylprednisolone (MP) to affect PPARγ expression and lipopolysaccharide (LPS)-induced MMP-9 activity. RESULTS: Monocytes/MDMs from RA patients have significantly enhanced PPARγ expression (both protein and mRNA) and MMP-9 activity as compared with healthy donors. Interestingly, cells from patients with less active disease (DAS-28 <3.2) present higher PPARγ protein expression and lower MMP-9 activity than RA patients with DAS-28 >3.2. At therapeutic concentrations, MTX and MP increase in vitro PPARγ protein expression and inhibit LPS-induced MMP-9 activity. CONCLUSION: PPARγ expression in human monocytes/MDMs could represent an indicator of disease activity and therapy efficacy in RA because patients with a DAS-28 score <3.2 show the highest expression.

The nitric oxide-donating pravastatin, NCX 6550, inhibits cytokine release and NF-κB activation while enhancing PPARγ expression in human monocyte/macrophages.

Previous studies have shown that NCX 6550 (NCX), a nitric oxide (NO)-donating pravastatin, induces anti-inflammatory effects in murine macrophage cell lines. Here, we have studied its activity in human monocyte/macrophages, by investigating cytokine release, NF-κB translocation and peroxisome proliferator-activated receptor γ (PPARγ) expression and function. For comparison, pravastatin, isosorbide-5-mononitrate (ISMN), sodium nitroprusside (SNP) and the PPARγ ligand 15-deoxy-Δ(12,14)-prostaglandin J(2) (PGJ) were also tested. Monocytes and macrophages (MDM: monocyte-derived macrophages) were isolated from healthy donors; cytokine release was measured by ELISA, NF-κB by electrophoretic mobility shift assay and PPARγ by Western blot and Real-Time PCR. NCX (1 nM-50 µM) dose-dependently inhibited phorbol 12-myristate 13-acetate (PMA)-induced TNF-α release from monocytes (IC(50)=240 nM) and MDM (IC(50)=52 nM). At 50 µM, it was more effective than pravastatin, ISMN and SNP (P<0.05), but less efficient than PGJ. Similar results were obtained for IL-6. Likewise, NCX was more effective than pravastatin and the other NO donors in inhibiting PMA-induced NF-κB translocation in both cell types, and, at the highest concentration, significantly (P<0.05) enhanced PPARγ protein expression in monocytes. We conclude that NCX 6550 exerts a significant anti-inflammatory activity in human monocyte/macrophages, that is also contributed by its NO donating properties, as the effects exerted by NCX are significantly higher than those evoked by pravastatin in many experimental assays. These data further indicate that the incorporation of a NO-donating moiety into a statin structure confers pharmacological properties which may translate into useful therapeutic benefits.