Targeting systemic inflammation in metabolic disorders. A therapeutic candidate for the prevention of cardiovascular diseases?

Cardiovascular disease (CVD) remains the leading cause of death and disability worldwide. While many factors can contribute to CVD, atherosclerosis is the cardinal underlying pathology, and its development is associated with several metabolic risk factors including dyslipidemia and obesity. Recent studies have definitively demonstrated a link between low-grade systemic inflammation and two relevant metabolic abnormalities: hypercholesterolemia and obesity. Interestingly, both metabolic disorders are also associated with endothelial dysfunction/activation, a proinflammatory and prothrombotic phenotype of the endothelium that involves leukocyte infiltration into the arterial wall, one of the earliest stages of atherogenesis. This article reviews the current literature on the intricate relationship between hypercholesterolemia and obesity and the associated systemic inflammation and endothelial dysfunction, and discusses the effectiveness of present, emerging and in-development pharmacological therapies used to treat these metabolic disorders with a focus on their effects on the associated systemic inflammatory state and cardiovascular risk.

Metabolomic signature and molecular profile of normal and degenerated human intervertebral disc cells.

BACKGROUND CONTEXT: Intervertebral disc degeneration (IVDD) is an incurable, specific treatment-orphan disease with an increasing burden worldwide. Although great efforts have been made to develop new regenerative therapies, their clinical success is limited. PURPOSE: Characterize the metabolomic and gene expression changes underpinning human disc degeneration. This study also aimed to disclose new molecular targets for developing and optimizing novel biological approaches for IVDD. STUDY DESIGN: Intervertebral disc cells were obtained from IVDD patients undergoing circumferential arthrodesis surgery or from healthy subjects. Mimicking the harmful microenvironment of degenerated discs, cells isolated from the nucleus pulposus (NP) and annulus fibrosus (AF) were exposed to the proinflammatory cytokine IL-1ß and the adipokine leptin. The metabolomic signature and molecular profile of human disc cells were unraveled for the first time. METHODS: The metabolomic and lipidomic profiles of IVDD and healthy disc cells were analyzed by high-performance liquid chromatography-mass spectrometry (UHPLC-MS). Gene expression was investigated by SYBR green-based quantitative real-time RT-PCR. Altered metabolites and gene expression were documented. RESULTS: Lipidomic analysis revealed decreased levels of triacylglycerols (TG), diacylglycerol (DG), fatty acids (FA), phosphatidylcholine (PC), lysophosphatidylinositols (LPI) and sphingomyelin (SM), and increased levels of bile acids (BA) and ceramides, likely promoting disc cell metabolism changing from glycolysis to fatty acid oxidation and following cell death. The gene expression profile of disc cells suggests LCN2 and LEAP2/GHRL as promising molecular therapeutic targets for disc degeneration and demonstrates the expression of genes related to inflammation (NOS2, COX2, IL-6, IL-8, IL-1ß, and TNF-α) or encoding adipokines (PGRN, NAMPT, NUCB2, SERPINE2, and RARRES2), matrix metalloproteinases (MMP9 and MMP13), and vascular adhesion molecules (VCAM1). CONCLUSIONS: Altogether, the presented results disclose the NP and AF cell biology changes from healthy to degenerated discs, allowing the identification of promising molecular therapeutic targets for intervertebral disc degeneration. CLINICAL SIGNIFICANCE: Our results are relevant to improving current biological-based strategies aiming to repair IVD by restoring cellular lipid metabolites as well as adipokines homeostasis. Ultimately, our results will be valuable for successful, long-lasting relief of painful IVDD.

Overview of Cellular and Soluble Mediators in Systemic Inflammation Associated with Non-Alcoholic Fatty Liver Disease.

Non-alcoholic fatty liver disease (NAFLD) is currently the most prevalent chronic liver disease in Western countries, affecting approximately 25% of the adult population. This condition encompasses a spectrum of liver diseases characterized by abnormal accumulation of fat in liver tissue (non-alcoholic fatty liver, NAFL) that can progress to non-alcoholic steatohepatitis (NASH), characterized by the presence of liver inflammation and damage. The latter form often coexists with liver fibrosis which, in turn, may progress to a state of cirrhosis and, potentially, hepatocarcinoma, both irreversible processes that often lead to the patient's death and/or the need for liver transplantation. Along with the high associated economic burden, the high mortality rate among NAFLD patients raises interest, not only in the search for novel therapeutic approaches, but also in early diagnosis and prevention to reduce the incidence of NAFLD-related complications. In this line, an exhaustive characterization of the immune status of patients with NAFLD is mandatory. Herein, we attempted to gather and compare the current and relevant scientific evidence on this matter, mainly on human reports. We addressed the current knowledge related to circulating cellular and soluble mediators, particularly platelets, different leukocyte subsets and relevant inflammatory soluble mediators.

Adipokines in Non-Alcoholic Fatty Liver Disease: Are We on the Road toward New Biomarkers and Therapeutic Targets?

Non-alcoholic fatty liver disease (NAFLD) has become the major cause of chronic hepatic illness and the leading indication for liver transplantation in the future decades. NAFLD is also commonly associated with other high-incident non-communicable diseases, such as cardiovascular complications, type 2 diabetes, and chronic kidney disease. Aggravating the socio-economic impact of this complex pathology, routinely feasible diagnostic methodologies and effective drugs for NAFLD management are unavailable. The pathophysiology of NAFLD, recently defined as metabolic associated fatty liver disease (MAFLD), is correlated with abnormal adipose tissue-liver axis communication because obesity-associated white adipose tissue (WAT) inflammation and metabolic dysfunction prompt hepatic insulin resistance (IR), lipid accumulation (steatosis), non-alcoholic steatohepatitis (NASH), and fibrosis. Accumulating evidence links adipokines, cytokine-like hormones secreted by adipose tissue that have immunometabolic activity, with NAFLD pathogenesis and progression; however, much uncertainty still exists. Here, the current knowledge on the roles of leptin, adiponectin, ghrelin, resistin, retinol-binding protein 4 (RBP4), visfatin, chemerin, and adipocyte fatty-acid-binding protein (AFABP) in NAFLD, taken from preclinical to clinical studies, is overviewed. The effect of therapeutic interventions on adipokines' circulating levels are also covered. Finally, future directions to address the potential of adipokines as therapeutic targets and disease biomarkers for NAFLD are discussed.

WISP-2 modulates the induction of inflammatory mediators and cartilage catabolism in chondrocytes.

Wnt-1 inducible signaling pathway protein 2 (WISP-2/CCN5) is a recently identified adipokine that has been described as an important mediator of canonical Wnt activation in adipogenic precursor cells. In osteoarthritis (OA), the most common form of arthritis, chondrocytes exhibit aberrant and increased production of pro-inflammatory mediators and matrix degrading enzymes such as IL-1ß and MMP-13. Although recent evidence suggests a role for Wnt signaling in OA physiopathology, little is known about the involvement of WISP-2 in cartilage degradation. In the present study, we determined the expression of WISP-2 in healthy and OA human chondrocytes. WISP-2 expression is modulated along chondrocyte differentiation and downregulated at the onset of hypertrophy by inflammatory mediators. We also investigated the effect of WISP-2 on cartilage catabolism and performed WISP-2 loss-of-function experiments using RNA interference technology in human T/C-28a2 immortalized chondrocytes. We demonstrated that recombinant human WISP-2 protein reduced IL-1ß-mediated chondrocyte catabolism, that IL-1ß and WNT/b-catenin signaling pathways are involved in rhWISP-2 protein and IL-1ß effects in human chondrocytes, and that WISP-2 has a regulatory role in attenuating the catabolic effects of IL-1ß in chondrocytes. Gene silencing of WISP-2 increased the induction of the catabolic markers MMP-13 and ADAMTS-5 and the inflammatory mediators IL-6 and IL-8 triggered by IL-1ß in human primary OA chondrocytes in a Wnt/ß-catenin dependent manner. In conclusion, here we have shown for the first time that WISP-2 may have relevant roles in modulating the turnover of extracellular matrix in the cartilage and that its downregulation may detrimentally alter the inflammatory environment in OA cartilage. We also proved the participation of Wnt/ß-catenin signaling pathway in these processes. Thus, targeting WISP-2 might represent a potential therapeutical approach for degenerative and/or inflammatory diseases of musculoskeletal system, such as osteoarthritis.

A new immunometabolic perspective of intervertebral disc degeneration.

Intervertebral disc (IVD) degeneration is a common finding on spine imaging that increases in prevalence with age. IVD degeneration is a frequent cause of low back pain, which is a leading cause of disability. The process of IVD degeneration consists of gradual structural change accompanied by severe alterations in metabolic homeostasis. IVD degeneration, like osteoarthritis, is a common comorbidity in patients with obesity and type 2 diabetes mellitus, two metabolic syndrome pathological conditions in which adipokines are important promoters of low-grade inflammation, extracellular matrix degradation and fibrosis. Impairment in white adipose tissue function, due to the abnormal fat accumulation in obesity, is characterized by increased production of specific pro-inflammatory proteins such as adipokines by white adipose tissue and of cytokines such as TNF by immune cells of the stromal compartment. Investigations into the immunometabolic alterations in obesity and type 2 diabetes mellitus and their interconnections with IVD degeneration provide insights into how adipokines might affect the pathogenesis of IVD degeneration and impair IVD function and repair. Toll-like receptor-mediated signalling has also been implicated as a promoter of the inflammatory response in the metabolic alterations associated with IVD and is thus thought to have a role in IVD degeneration. Pathological starvation, obesity and adipokine dysregulation can result in immunometabolic alterations, which could be targeted for the development of new therapeutics.

Metformin reduces macrophage HIF1α-dependent proinflammatory signaling to restore brown adipocyte function in vitro.

Therapeutic potential of metformin in obese/diabetic patients has been associated to its ability to combat insulin resistance. However, it remains largely unknown the signaling pathways involved and whether some cell types are particularly relevant for its beneficial effects. M1-activation of macrophages by bacterial lipopolysaccharide (LPS) promotes a paracrine activation of hypoxia-inducible factor-1α (HIF1α) in brown adipocytes which reduces insulin signaling and glucose uptake, as well as ß-adrenergic sensitivity. Addition of metformin to M1-polarized macrophages blunted these signs of brown adipocyte dysfunction. At the molecular level, metformin inhibits an inflammatory program executed by HIF1α in macrophages by inducing its degradation through the inhibition of mitochondrial complex I activity, thereby reducing oxygen consumption in a reactive oxygen species (ROS)-independent manner. In obese mice, metformin reduced inflammatory features in brown adipose tissue (BAT) such as macrophage infiltration, proinflammatory signaling and gene expression, and restored the response to cold exposure. In conclusion, the impact of metformin on macrophages by suppressing a HIF1α-dependent proinflammatory program is likely responsible for a secondary beneficial effect on insulin-mediated glucose uptake and ß-adrenergic responses in brown adipocytes.

Monomeric C reactive protein (mCRP) regulates inflammatory responses in human and mouse chondrocytes.

C-reactive protein (CRP) is an acute-phase protein that is used as an established biomarker to follow disease severity and progression in a plethora of inflammatory diseases. However, its pathophysiologic mechanisms of action are still poorly defined and remain elusive. CRP, in its pentameric form, exhibits weak anti-inflammatory activity. On the contrary, the monomeric isoform (mCRP) exhibits potent pro-inflammatory properties in endothelial cells, leukocytes, and platelets. So far, no data exists regarding mCRP effects in human or mouse chondrocytes. This work aimed to verify the pathophysiological relevance of mCRP in the etiology and/or progression of osteoarthritis (OA). We investigated the effects of mCRP in cultured human primary chondrocytes and in the chondrogenic ATDC5 mouse cell line. We determined mRNA and protein levels of relevant factors involved in inflammatory responses and the modulation of nitric oxide synthase type II (NOS2), an early inflammatory molecular target. We demonstrate, for the first time, that monomeric C reactive protein increases NOS2, COX2, MMP13, VCAM1, IL-6, IL-8, and LCN2 expression in human and murine chondrocytes. We also demonstrated that NF-kB is a key factor in the intracellular signaling of mCRP-driven induction of pro-inflammatory and catabolic mediators in chondrocytes. We concluded that mCRP exerts a sustained catabolic effect on human and murine chondrocytes, increasing the expression of inflammatory mediators and proteolytic enzymes, which can promote extracellular matrix (ECM) breakdown in healthy and OA cartilage. In addition, our results implicate the NF-kB signaling pathway in catabolic effects mediated by mCRP.

Pharmacological Extracts and Molecules from Virola Species: Traditional Uses, Phytochemistry, and Biological Activity.

Virola is the largest genus of Myristicaceae in America, comprising about 60 species of medium-sized trees geographically spread from Mexico to southern Brazil. The plant species of this genus have been widely used in folk medicine for the treatment of several ailments, such as rheumatic pain, bronchial asthma, tumors in the joints, intestinal worms, halitosis, ulcers, and multiple infections, due to their pharmacological activity. This review presents an updated and comprehensive summary of Virola species, particularly their ethnomedicinal uses, phytochemistry, and biological activity, to support the safe medicinal use of plant extracts and provide guidance for future research. The Virola spp.'s ethnopharmacology, including in the treatment of stomach pain and gastric ulcers, as well as antimicrobial and tryponosomicidal activities, is attributable to the presence of a myriad of phytoconstituents, such as flavonoids, tannins, phenolic acids, lignans, arylalkanones, and sitosterol. Hence, such species yield potential leads or molecular scaffolds for the development of new pharmaceutical formulations, encouraging the elucidation of not-yet-understood action mechanisms and ascertaining their safety for humans.

Evaluation of Virola oleifera activity in musculoskeletal pathologies: Inhibition of human multiple myeloma cells proliferation and combination therapy with dexamethasone or bortezomib.

ETHNOPHARMACOLOGICAL RELEVANCE: Virola oleifera (Schott) A.C. Smith, Myristicaceae, has been widely used in traditional medicine in Brazil to treat rheumatic pain, joint tumours, skin diseases, halitosis, bronchial asthma, haemorrhoids, and intestinal worms. Recently, research data showed the antioxidant properties in several oxidative stress-related models. However, there is no experimental evidence supporting its potential use in managing rheumatic diseases and bone malignancies. AIMS OF THE STUDY: To evaluate the therapeutic potential of the resin from Virola oleifera in joint and bone diseases, namely arthritis, osteosarcoma, chondrosarcoma, and multiple myeloma. MATERIALS AND METHODS: To determine Virola oleifera resin (VO) effects on arthritis-associated inflammation and cartilage degradation, the LPS-induced NO production, and mRNA and protein expression of ADAMTS5, MMP13, COL2, and ACAN, were evaluated in chondrocytes (ATDC5 and TC28 cell lines). The cytotoxic effects of VO (0.05-50 µg/ml) on multiple myeloma (ARH-77), osteosarcoma (SAOS-2), and chondrosarcoma (SW-1353) cell lines were analysed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. The VO effects, combined with dexamethasone or bortezomib, were evaluated in a multiple myeloma cell line. The mechanisms of VO, alone or in combination with bortezomib, were determined by cell cycle analysis through flow cytometry, while expression levels of p-Akt/Akt, p-ERK/ERK, p-p38/p38 MAPK, Bax, Bcl-2, and cleaved-caspase-3/caspase-3 proteins by Western blot. RESULTS: VO had no significant effect on LPS-induced NO production in chondrocytes at non-cytotoxic concentrations. VO treatment diminished the mRNA levels of metalloproteinases and ECM components; however, any significant effect was observed on the protein expression levels. The cell viability of a multiple myeloma cell line was strongly reduced by VO treatment in a dose- and time-dependent manner, while osteosarcoma and chondrosarcoma cell lines viability was significantly affected only by the highest dose assessed. In multiple myeloma cells, VO leads to G2/M cell cycle arrest. Furthermore, it synergizes with dexamethasone by increasing cell toxicity. Finally, VO reverts bortezomib activity by counteracting ERK1/2, Bax, and caspase-3 activation. CONCLUSIONS: The current work supports the ethnopharmacological use of Virola oleifera (Schott) A.C. Smith in bone and joint diseases, but there is no evidence for the amelioration of arthritis-associated inflammatory or catabolic processes. Our data also supports the potential use of Virola oleifera as adjuvant therapy to optimize the pharmacologic effects of current chemotherapeutic drugs. However, possible herb-drug interactions should be considered before clinical application.

Dickkopf-3 (DKK3) Signaling in IL-1α-Challenged Chondrocytes: Involvement of the NF-κB Pathway.

OBJECTIVE: Osteoarthritis (OA) is an age-related biomechanical and low-grade inflammometabolic disease of the joints and one of the costliest and disabling forms of arthritis. Studies on matrix-degrading enzymes such as metalloproteases, which are implicated in the increased catabolism of extracellular matrix, are of paramount relevance. DKK3 is a member of DKK family and is best known for its role in cancer. Although there is some information about the participation of DKK3 in cartilage pathophysiology and on metalloproteases regulation, in particular, little is known about DKK3 signaling mechanisms. Thus, the aim of this study is to explore how DKK3 regulates matrix metalloproteinase-13 (MMP-13) expression. DESIGN: Gene, protein expression and protein phosphorylation in primary human chondrocytes and ATDC5 mouse cells were assessed by RT-qPCR and Western blot analysis. Further studies on DKK3 activity were performed by targeting DKK3 gene with a specific siRNA. RESULTS: DKK3 expression was found to be higher in OA human chondrocytes than healthy cells, being its expression decreased in interleukin-1α (IL-1α)-stimulated cells. DKK3 knockdown increased the induction of MMP-13 elicited by IL-1α in human and mouse chondrocytes and after the analysis of different signalling pathways, we observed that NF-κB pathway was involved in the regulation of MMP-13 expression by DKK3. CONCLUSIONS: Herein we have demonstrated, for the first time, that DKK3 gene silencing exacerbated NF-κB activation, resulting in an increased IL-1α-driven induction of MMP-13. Our results further confirm that DKK3 may play a protective role in OA by attenuating NF-κB activation and the subsequent production of metalloproteases.

Lavandula viridis L´Hér. Essential Oil Inhibits the Inflammatory Response in Macrophages Through Blockade of NF-KB Signaling Cascade.

Lavandula viridis L´Hér. is an endemic Iberian species with a high essential oil yield and a pleasant lemon scent. Despite these interesting features, this species remains unrecognized and poorly explored by the food and pharmaceutical industries. Nevertheless, it has been valued in traditional medicine being used against flu, circulatory problems and to relieve headaches. Since these disorders trigger inflammatory responses, it is relevant to determine the anti-inflammatory potential of L. viridis L´Hér. essential oil in an attempt to validate its traditional use and concomitantly to increment its industrial exploitation. Therefore, in the present study the chemical composition of this volatile extract as well as the effect on ROS production, inflammatory response and proteasome activity on LPS-stimulated macrophages were disclosed. Also, its safety profile on keratinocytes, hepatocytes and alveolar epithelial cells was depicted, envisioning a future human administration. The essential oil was characterized by high quantities of 1,8-cineole, camphor and α-pinene. From a pharmacological point of view, the essential oil showed a potent antioxidant effect and inhibited nitric oxide production through down-modulation of nuclear factor kappa B-dependent Nos2 transcription and consequently iNOS protein expression as well as a decrease in proteasomal activity. The anti-inflammatory activity was also evidenced by a strong inhibition of LPS-induced Il1b and Il6 transcriptions and downregulation of COX-2 levels. Overall, bioactive safe concentrations of L. viridis L´Hér. essential oil were disclosed, thus corroborating the traditional usage of this species and paving the way for the development of plant-based therapies.

Levels of the Novel Endogenous Antagonist of Ghrelin Receptor, Liver-Enriched Antimicrobial Peptide-2, in Patients with Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is a debilitating, chronic, inflammatory, autoimmune disease associated with cachexia. The substitutive therapy of gut hormone ghrelin has been pointed at as a potential countermeasure for the management of metabolic and inflammatory complications in RA. The recent discovery of liver-expressed antimicrobial peptide 2 (LEAP2) as an endogenous inverse agonist/antagonist of the ghrelin receptor makes feasible the development of a more rational pharmacological approach. This work aimed to assess the serum LEAP2 levels, in a cohort of RA patients, in comparison with healthy individuals and determine its correlation with inflammatory parameters. LEAP2 levels were determined by a commercial ELISA kit, plasma C-reactive protein (CRP) levels were evaluated using immunoturbidimetry, and serum levels of inflammatory mediators, namely IL-6, IL-8, IL-1ß, MIP1α, MCP1, and LCN2, were measured by XMap multiplex assay. LEAP2 serum levels were significantly increased in RA patients (n = 101) compared with control subjects (n = 26). Furthermore, the LEAP2 levels significantly correlated with CRP and inflammatory cytokines, but not with BMI. These data reveal LEAP2 as a new potential RA biomarker and indicated the pharmacological control of LEAP2 levels as a novel approach for the treatment of diseases with alterations on the ghrelin levels, such as rheumatoid cachexia.

Visfatin Connection: Present and Future in Osteoarthritis and Osteoporosis.

Musculoskeletal pathologies (MSPs) such as osteoarthritis (OA) and osteoporosis (OP), are a set of disorders that cause severe pain, motion difficulties, and even permanent disability. In developed countries, the current incidence of MSPs reaches about one in four adults and keeps escalating as a consequence of aging and sedentarism. Interestingly, OA and OP have been closely related to similar risk factors, including aging, metabolic alterations, and inflammation. Visfatin, an adipokine with an inflammatory and catabolic profile, has been associated with several OA and OP metabolic risk factors, such as obesity, insulin resistance, and type II diabetes. Furthermore, visfatin has been associated with the innate immune receptor toll-like receptor 4 (TLR4), which plays a key role in cartilage and bone inflammatory and catabolic responses. Moreover, visfatin has been related to several OA and OP pathologic features. The aim of this work is to bring together basic and clinical data regarding the common role of visfatin in these pathologies and their major shared risk factors. Finally, we discuss the pitfalls of visfatin as a potential biomarker and therapeutic target in both pathologies.

Molecular Relationships among Obesity, Inflammation and Intervertebral Disc Degeneration: Are Adipokines the Common Link?

Intervertebral disc degeneration (IVDD) is a chronic, expensive, and high-incidence musculoskeletal disorder largely responsible for back/neck and radicular-related pain. It is characterized by progressive degenerative damage of intervertebral tissues along with metabolic alterations of all other vertebral tissues. Despite the high socio-economic impact of IVDD, little is known about its etiology and pathogenesis, and currently, no cure or specific treatments are available. Recent evidence indicates that besides abnormal and excessive mechanical loading, inflammation may be a crucial player in IVDD. Furthermore, obese adipose tissue is characterized by a persistent and low-grade production of systemic pro-inflammatory factors. In this context, chronic low-grade inflammation associated with obesity has been hypothesized as an important contributor to IVDD through different, but still unknown, mechanisms. Adipokines, such as leptin, produced prevalently by white adipose tissues, but also by other cells of mesenchymal origin, particularly cartilage and bone, are cytokine-like hormones involved in important physiologic and pathophysiological processes. Although initially restricted to metabolic functions, adipokines are now viewed as key players of the innate and adaptative immune system and active modulators of the acute and chronic inflammatory response. The goal of this review is to summarize the most recent findings regarding the interrelationships among inflammation, obesity and the pathogenic mechanisms involved in the IVDD, with particular emphasis on the contribution of adipokines and their potential as future therapeutic targets.

Natural Molecules for Healthy Lifestyles: Oleocanthal from Extra Virgin Olive Oil.

Extra virgin olive oil (EVOO) is the main source of fat in the Mediterranean diet. Phenolic compounds of EVOO, in particular, secoiridoids, are minor components that have generated special interest due to their positive effects on human health, supported by several clinical trials. This review summarizes the most recent findings on the pharmacological properties and action's mechanisms of secoiridoid oleocanthal, focusing attention on inflammation, oxidative stress, cancer, neurodegenerative processes, and rheumatic diseases. Being of relevance to the clinical effects of EVOO intake, the bioavailability and biotransformation of EVOO polyphenols are addressed. Moreover, this review summarizes the factors that may influence the oleocanthal concentration in EVOO. With the growing incidence of age- and lifestyle-related diseases, the current data indicated that the administration of EVOO rich in secoiridoids may be helpful in the prevention or treatment of different pathologies with an inflammatory component. Although promising, the future raises several questions and challenges, which are discussed here. The real beneficial effects of olive oil phenols on human health need to be clarified in new, well-designed clinical studies.

Adipokines: Linking metabolic syndrome, the immune system, and arthritic diseases.

Metabolic syndrome (MetS) represents a cluster of metabolic and cardiovascular complications, including obesity and visceral adiposity, insulin resistance, dyslipidemia, hyperglycemia and hypertension, which directly increase the risk of cardiovascular diseases (CVD) and diabetes mellitus type 2 (DM2). Patients with arthritic diseases, such as rheumatoid arthritis and osteoarthritis, have a higher incidence of CVD. Although recent advances in the treatment of arthritic diseases, the incidence of CVD remains elevated, and MetS has been identified as a possible link between CVD and arthritic diseases. Chronic low-grade inflammation associated with obesity has been established as a significant contributing factor to the increased prevalence of MetS. Adipokines, which play important physiological roles in metabolic activities contributing to the pathogenesis of MetS, are also involved in the regulation of autoimmune and/or inflammatory processes associated with arthritic diseases. Therefore, MetS and dysregulated secretion of pro-inflammatory adipokines have been recognized as a molecular link between CVD and arthritis diseases. In the present paper, we review recent evidence supporting the role played by adipokines, in particular leptin, adiponectin, and lipocalin-2, in the modulation of the immune system, MetS and arthritic diseases. The underlying cellular and molecular mechanisms are discussed, as well as potential new therapeutic strategies.

Butyrate Modulates Inflammation in Chondrocytes via GPR43 Receptor.

BACKGROUND/AIMS: Osteoarthritis (OA) is a joint degenerative biomechanical disorder involving immunity, metabolic alterations, inflammation, and cartilage degradation, where chondrocytes play a pivotal role. OA has not effective pharmacological treatments and new therapeutic targets are needed. Adipokines contribute to the low-grade systemic inflammation in OA. Here, we explored novel molecular mechanisms of sodium butyrate (BuNa) in modulating inflammation and chemotaxis in chondrocytes, demonstrating the direct involvement of its G protein-coupled receptor (GPR)-43. METHODS: ATDC5 murine chondrocytes were stimulated with interleukin (IL)-1ß, in the presence or not of BuNa, for 24 h. RT-PCR and Western blot analysis was performed to evaluate the expression of inflammatory mediators and structural proteins. RESULTS: Butyrate reduced the expression of canonic pro-inflammatory mediators (Nos2, COX-2, IL-6), pro-inflammatory adipokines (lipocalin-2 and nesfatin-1) and adhesion molecule (VCAM-1 and ICAM-1) in IL-1ß-stimulated chondrocytes, inhibiting several inflammatory signalling pathways (NFκB, MAPKinase, AMPK-α, PI3K/Akt). Butyrate also reduced metalloproteinase production and limited the loss of type II collagen in IL-1ß-inflamed chondrocytes. The chemoattractant effect of butyrate, after different inflammatory challenges, was revealed by increased annexin (AnxA)1 levels and chemokines expression. The chemoattractant and anti-inflammatory activities of butyrate were completely blunted by GPR43 silencing using RNA interference. CONCLUSION: Taken together, our data suggest the potential application of sodium butyrate as a novel candidate in a multi-target approach for the treatment of chondrocyte inflammation and cartilage degenerative process.

Oleocanthal Inhibits Catabolic and Inflammatory Mediators in LPS-Activated Human Primary Osteoarthritis (OA) Chondrocytes Through MAPKs/NF-κB Pathways.

BACKGROUND/AIMS: Oleocanthal (OC), a phenolic compound present in extra virgin olive oil (EVOO), has attracted attention since its discovery for its relevant pharmacological properties in different pathogenic processes, including inflammation. Here, we investigated the involvement of OC in LPS-activated osteoarthritis (OA) human primary chondrocytes. METHODS: Human primary chondrocytes were harvested from articular cartilage samples obtained from OA patients. The effects of OC on the viability of chondrocytes were tested by MTT assay. Protein and mRNA expression of several catabolic and pro-inflammatory factors after OC treatment were measured by RT-qPCR and western blot respectively. Moreover, we analysed the NO production by Griess reaction. Finally, several pathways mediators were analysed by western blot. RESULTS: We demonstrated that OC did not have any cytotoxic effect. Oleocanthal inhibited NO production and strongly decreased NOS2 and COX-2 protein and mRNA expression in LPS-activated human primary OA chondrocytes. Interestingly, OC also inhibits MMP-13 and ADAMTS-5. In addition, OC downregulates several pro-inflammatory factors, such as IL-6, IL-8, CCL3, LCN2 and TNF-α induced by LPS in human primary OA chondrocytes. Finally, we demonstrated that OC exerts its effects through the MAPK/P38/NF-kB pathways. CONCLUSION: These data show that OC is able to block LPS-mediated inflammatory response and MMP-13 and ADAMTS-5 induction in human primary OA chondrocytes via MAPKs/NF-kB pathways, suggesting that OC may be a promising agent for the treatment of inflammation in cartilage and a potential molecule to prevent disease progression by inhibiting metalloproteases and aggrecanases.

Obesity, Fat Mass and Immune System: Role for Leptin.

Obesity is an epidemic disease characterized by chronic low-grade inflammation associated with a dysfunctional fat mass. Adipose tissue is now considered an extremely active endocrine organ that secretes cytokine-like hormones, called adipokines, either pro- or anti-inflammatory factors bridging metabolism to the immune system. Leptin is historically one of most relevant adipokines, with important physiological roles in the central control of energy metabolism and in the regulation of metabolism-immune system interplay, being a cornerstone of the emerging field of immunometabolism. Indeed, leptin receptor is expressed throughout the immune system and leptin has been shown to regulate both innate and adaptive immune responses. This review discusses the latest data regarding the role of leptin as a mediator of immune system and metabolism, with particular emphasis on its effects on obesity-associated metabolic disorders and autoimmune and/or inflammatory rheumatic diseases.