Human Synovial Mesenchymal Stem Cells Expressed Immunoregulatory Factors IDO and TSG6 in a Context of Arthritis Mediated by Alphaviruses.

Infection by arthritogenic alphaviruses (aavs) can lead to reactive arthritis, which is characterized by inflammation and persistence of the virus; however, its mechanisms remain ill-characterized. Intriguingly, it has been shown that viral persistence still takes place in spite of robust innate and adaptive immune responses, characterized notably by the infiltration of macrophages (sources of TNF-alpha) as well as T/NK cells (sources of IFN-gamma) in the infected joint. Aavs are known to target mesenchymal stem cells (MSCs) in the synovium, and we herein tested the hypothesis that the infection of MSCs may promote the expression of immunoregulators to skew the anti-viral cellular immune responses. We compared the regulated expression via human synovial MSCs of pro-inflammatory mediators (e.g., IL-1ß, IL6, CCL2, miR-221-3p) to that of immunoregulators (e.g., IDO, TSG6, GAS6, miR146a-5p). We used human synovial tissue-derived MSCs which were infected with O'Nyong-Nyong alphavirus (ONNV, class II aav) alone, or combined with recombinant human TNF-α or IFN-γ, to mimic the clinical settings. We confirmed via qPCR and immunofluorescence that ONNV infected human synovial tissue-derived MSCs. Interestingly, ONNV alone did not regulate the expression of pro-inflammatory mediators. In contrast, IDO, TSG6, and GAS6 mRNA expression were increased in response to ONNV infection alone, but particularly when combined with both recombinant cytokines. ONNV infection equally decreased miR-146a-5p and miR-221-3p in the untreated cells and abrogated the stimulatory activity of the recombinant TNF-α but not the IFN-gamma. Our study argues for a major immunoregulatory phenotype of MSCs infected with ONNV which may favor virus persistence in the inflamed joint.

Anti-Alphaviral Alkaloids: Focus on Some Isoquinolines, Indoles and Quinolizidines.

The discovery and the development of safe and efficient therapeutics against arthritogenic alphaviruses (e.g., chikungunya virus) remain a continuous challenge. Alkaloids are structurally diverse and naturally occurring compounds in plants, with a wide range of biological activities including beneficial effects against prominent pathogenic viruses and inflammation. In this short review, we discuss the effects of some alkaloids of three biologically relevant structural classes (isoquinolines, indoles and quinolizidines). Based on various experimental models (viral infections and chronic diseases), we highlight the immunomodulatory effects of these alkaloids. The data established the capacity of these alkaloids to interfere in host antiviral and inflammatory responses through key components (antiviral interferon response, ROS production, inflammatory signaling pathways and pro- and anti-inflammatory cytokines production) also involved in alphavirus infection and resulting inflammation. Thus, these data may provide a convincing perspective of research for the use of alkaloids as immunomodulators against arthritogenic alphavirus infection and induced inflammation.

Artemisia annua, a Traditional Plant Brought to Light.

Traditional remedies have been used for thousand years for the prevention and treatment of infectious diseases, particularly in developing countries. Of growing interest, the plant Artemisia annua, known for its malarial properties, has been studied for its numerous biological activities including metabolic, anti-tumor, anti-microbial and immunomodulatory properties. Artemisia annua is very rich in secondary metabolites such as monoterpenes, sesquiterpenes and phenolic compounds, of which the biological properties have been extensively studied. The purpose of this review is to gather and describe the data concerning the main chemical components produced by Artemisia annua and to describe the state of the art about the biological activities reported for this plant and its compounds beyond malaria.

Evaluation of core-shell Fe3O4@Au nanoparticles as radioenhancer in A549 cell lung cancer model.

In radiotherapy, metallic nanoparticles are of high interest in the fight against cancer for their radiosensitizing effects. This study aimed to evaluate the ability of core-shell Fe3O4@Au nanoparticles to potentiate the irradiation effects on redox-, pro-inflammatory markers, and cell death of A549 human pulmonary cancer cells. The hybrid Fe3O4@Au nanoparticles were synthesized using green chemistry principles by the sonochemistry method. Their characterization by transmission electron microscopy demonstrated an average size of 8 nm and a homogeneous distribution of gold. The decreased hydrodynamic size of these hybrid nanoparticles compared to magnetite (Fe3O4) nanoparticles showed that gold coating significantly reduced the aggregation of Fe3O4 particles. The internalization and accumulation of the Fe3O4@Au nanoparticles within the cells were demonstrated by Prussian Blue staining. The reactive oxygen species (ROS) levels measured by the fluorescent probe DCFH-DA were up-regulated, as well as mRNA expression of SOD, catalase, GPx antioxidant enzymes, redox-dependent transcription factor Nrf2, and ROS-producing enzymes (Nox2 and Nox4), quantified by RT-qPCR. Furthermore, irradiation coupled with Fe3O4@Au nanoparticles increased the expression of canonical pro-inflammatory cytokines and chemokines (TNF-α, IL-1ß, IL-6, CXCL8, and CCL5) assessed by RT-qPCR and ELISA. Hybrid nanoparticles did not potentiate the increased DNA damage detected by immunofluorescence following the irradiation. Nevertheless, Fe3O4@Au caused cellular damage, leading to apoptosis through activation of caspase 3/7, secondary necrosis quantified by LDH release, and cell growth arrest evaluated by clonogenic-like assay. This study demonstrated the potential of Fe3O4@Au nanoparticles to potentiate the radiosensitivity of cancerous cells.

Deciphering the Role of the Anaphylatoxin C3a: A Key Function in Modulating the Tumor Microenvironment.

The complement system plays a crucial role in cancer development. Our study investigated the role of C3a anaphylatoxin on the tumor microenvironment. Our models consisted of mesenchymal stem cells (MSC-like, 3T3-L1), macrophages (Raw 264.7 Blue, (RB)) and tumor cells (melanoma B16/F0). Recombinant mouse (Mo) C3a (rC3a) was produced in CHO cells transfected with a Mo-IL10-signal peptide-Mo C3a plasmid construct. The effects of rC3a, IFN-γ, TGF-ß1, and LPS were tested on the expression of C3, C3aR, PI3K, cytokines, chemokines, transcription factors, antioxidant defense mechanisms, angiogenesis and macrophage polarization (M1/M2). 3T3-L1 expressed the highest levels of C3, while C3aR was expressed more by RB. Interestingly, expression of C3/3T3-L1 and C3aR/RB was markedly upregulated by IFN-γ. rC3a was found to upregulate the expression of anti-inflammatory cytokines (IL-10) on 3T3-L1 and TGF-ß1 on RB. rC3a also upregulated the expression of pro-inflammatory cytokines in RB. The expression of CCL-5 increased in 3T3-L1 in response to rC3a. On RB, rC3a did not alter M1/M2 polarization but upregulated the expression of antioxidant defense genes, HO-1, and VEGF. C3/C3a produced mainly by MSC may play a critical role in TME remodeling by stimulating both anti-inflammatory and proangiogenic activities of tumor stromal cells.

Deciphering the Antifibrotic Property of Metformin.

Fibrosis is a chronic progressive and incurable disease leading to organ dysfunction. It is characterized by the accumulation of extracellular matrix proteins produced by mesenchymal stem cells (MSCs) differentiating into myofibroblasts. Given the complexity of its pathophysiology, the search for effective treatments for fibrosis is of paramount importance. Metformin, a structural dimethyl analog of the galegine guanide extracted from the "French Lilac" (Fabaceae Galega officinalis), is the most widely used antidiabetic drug, recently recognized for its antifibrotic effects through ill-characterized mechanisms. The in vitro model of TGF-ß1-induced fibrosis in human primary pulmonary mesenchymal stem cells (HPMSCs), identified as CD248+ and CD90+ cells, was used to study the effects of metformin extracts. These effects were tested on the expression of canonical MSC differentiation markers, immune/inflammatory factors and antioxidative stress molecules using qRT-PCR (mRNA, miRNA), immunofluorescence and ELISA experiments. Interestingly, metformin is able to reduce/modulate the expression of different actors involved in fibrosis. Indeed, TGF-ß1 effects were markedly attenuated by metformin, as evidenced by reduced expression of three collagen types and Acta2 mRNAs. Furthermore, metformin attenuated the effects of TGF-ß1 on the expression of PDGF, VEGF, erythropoietin, calcitonin and profibrotic miRs, possibly by controlling the expression of several key TGF/Smad factors. The expression of four major fibrogenic MMPs was also reduced by metformin treatment. In addition, metformin controlled MSC differentiation into lipofibroblasts and osteoblasts and had the ability to restore redox balance via the Nox4/Nrf2, AMP and Pi3K pathways. Overall, these results show that metformin is a candidate molecule for antifibrotic effect and/or aiming to combat the development of chronic inflammatory diseases worldwide.

Focus on the high therapeutic potentials of quercetin and its derivatives.

Background: Polyphenols and particularly flavonoids are of constant interest to the scientific community. Flavonoids are investigated for their biological and pharmacological purposes, notably as antioxidant, anticancer, antiviral and for their anti-inflammatory activities. Certainly, one of the best-known flavonols recognized for its therapeutic and preventive properties, is quercetin. Despite its biological interest, quercetin suffer from some drawbacks, mainly related to its bioavailability. Hence, its synthetic or biosynthetic derivatives have been the subject of intensive research. The health-promoting biological activities of flavonols and derivatives mainly arise from their capacity to disrupt the host-pathogen interactions and/or to regulate host cellular functions including oxidative processes and immunological responses. In the age of coronavirus pandemic, the anti-inflammatory and antiviral potential of flavonols should be put forward to explore these substances for decreasing the viral load and inflammatory storm caused by the infection. Purpose of study: The present review will decipher and discuss the antioxidant, anti-inflammatory and antiviral capacities of major flavonol with a focus on the molecular basis and structure-activity relationships. Study design: Current study used a combination of quercetin derivatives, pathway, antioxidant, anti-inflammatory, antiviral activities as keywords to retrieve the literature. This study critically reviewed the current literature and presented the ability of natural analogs of quercetin having superior antioxidant, anti-inflammatory and antiviral effects than the original molecule. Results: This review allowed the identification of relevant key structure-activity relationship elements and highlight approaches on the mechanisms governing the antioxidant, antiviral and anti-inflammatory activities. Conclusion: Through a critical analysis of the literature, flavonols and more precisely quercetin derivatives reviewed and found to act simultaneously on inflammation, virus and oxidative stress, three key factors that may lead to life threatening diseases.

Quercetin can reduce viral RNA level of O'nyong-nyong virus and resulting innate immune cytokine responses in cultured human synovial fibroblasts.

O'nyong-nyong virus is an alphavirus closely related to chikungunya virus, causing arthralgia, rash and fever. Alphaviruses mainly target synovial fibroblasts and persists in the joints of patients, possibly leading to chronic arthritis. To date, no specific antiviral treatment is available for ONNV infection and induced-inflammation. Primary human synovial fibroblasts cells were used to assess infection by ONNV and the resulting cytokine responses. Phenolics (gallic acid, caffeic acid and chlorogenic acid, curcumin and quercetin) and a curcuminoids-rich extract from turmeric were tested for their antiviral and anti-inflammatory capacities. We showed that infection occurred in HSF cells and increased gene expression and protein secretion of two major proinflammatory CCL-2 and IL-1ß markers. In ONNV-infected HSF cells (MOI 1), we found that non-cytotoxic concentrations of phenolics (10 µM) reduced the level of viral RNA (E1, E2, nsP1, nsP2) and downregulated CCL-2 and IL-1ß expression and secretion. These results highlighted the high value of the flavonol quercetin to reduce viral RNA levels and inflammatory status induced by ONNV in HSF cells.

Robust COX-2-mediated prostaglandin response may drive arthralgia and bone destruction in patients with chronic inflammation post-chikungunya.

Patients following infection by chikungunya virus (CHIKV) can suffer for months to years from arthralgia and arthritis. Interestingly, methotrexate (MTX) a major immune-regulatory drug has proved to be of clinical benefit. We have previously shown that CHIKV can persist in the joint of one patient 18 months post-infection and plausibly driving chronic joint inflammation but through ill-characterized mechanisms. We have pursued our investigations and report novel histological and in vitro data arguing for a plausible role of a COX-2-mediated inflammatory response post-CHIKV. In the joint, we found a robust COX-2 staining on endothelial cells, synovial fibroblasts and more prominently on multinucleated giant cells identified as CD11c+ osteoclasts known to be involved in bone destruction. The joint tissue was also strongly stained for CD3, CD8, CD45, CD14, CD68, CD31, CD34, MMP2, and VEGF (but not for NO synthase and two B cell markers). Dendritic cells were rarely detected. Primary human synovial fibroblasts were infected with CHIKV or stimulated either by the synthetic molecule polyriboinosinic:polyribocytidylic acid (PIC) to mimic chronic viral infection or cytokines. First, we found that PIC and CHIKV enhanced mRNA expression of COX-2. We further found that PIC but not CHIKV increased the mRNA levels of cPLA2α and of mPGES-1, two other central enzymes in PGE2 production. IFNß upregulated cPLA2α and COX-2 transcription levels but failed to modulated mPGES-1 mRNA expression. Moreover, PIC, CHIKV and IFNß decreased mRNA expression of the PGE2 degrading enzyme 15-PGDH. Interestingly, MTX failed to control the expression of all these enzymes. In sharp contrast, dexamethasone was able to control the capacity of pro-inflammatory cytokines, IL-1ß as well as TNFα, to stimulate mRNA levels of cPLA2α, COX-2 and mPGES-1. These original data argue for a concerted action of CHIKV (including viral RNA) and cytokines plausibly released from recruited leukocytes to drive a major COX-2-mediated PGE2 proinflammatory responses to induce viral arthritis.

Robust and low-cost ELISA based on IgG-Fc tagged recombinant proteins to screen for anti-SARS-CoV-2 antibodies.

The development of new diagnostic assays become a priority for managing COVID-19. To this aim, we presented here an in-house ELISA based on the production of two major recombinant and high-quality antigens from SARS-CoV-2. Full-length N and S-RBD fragment proteins fused to mouse IgG2a-Fc were produced in the CHO cell line. Secreted recombinant proteins were easily purified with standard Protein A chromatography and were used in an in-house ELISA to detect anti-N and anti-RBD IgGs in the plasma of COVID-19 RTPCR-positive patients. High reactivity against recombinant antigens was readily detected in all positive plasma samples, whereas no recognition was observed with control healthy subject's plasmas. Remarkably, unpurified recombinant N protein obtained from cell culture supernatant was also suitable for the monitoring by ELISA of IgG levels in positive patients. This work provides an early prospection for low price but high-quality serological kit development.

Serological Surveillance of COVID-19 Hospitalized Patients in Réunion Island (France) Revealed that Specific Immunoglobulin G Are Rapidly Vanishing in Severe Cases.

Humoral immunity is critically important to control COVID-19. Long-term antibody responses remain to be fully characterized in hospitalized patients who have a high risk of death. We compared specific Immunoglobulin responses against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) between two groups, intensive care unit (ICU) and non-ICU hospitalized patients over several weeks. Plasma specific IgG, IgM, and IgA levels were assessed using a commercial ELISA and compared to an in-house cell-based ELISA. Among the patients analyzed (mean (SD) of age, 64.4 (15.9) years, 19.2% female), 12 (46.2%) were hospitalized in ICU. IgG levels increased in non-ICU cases from the second to the eighth week after symptom onset. By contrast, IgG response was blunted in ICU patients over the same period. ICU patients with hematological malignancies had very weak or even undetectable IgG levels. While both groups had comparable levels of specific IgM antibodies, we found much lower levels of specific IgA in ICU versus non-ICU patients. In conclusion, COVID-19 ICU patients may be at risk of reinfection as their specific IgG response is declining in a matter of weeks. Antibody neutralizing assays and studies on specific cellular immunity will have to be performed.

Fruits and vegetables, as a source of nutritional compounds and phytochemicals: Changes in bioactive compounds during lactic fermentation.

Nutritional recommendations emphasize fruit and vegetable consumption. This is related to health-benefits associated with bioactive nutritive molecules (nutrients, vitamins, minerals, fibers, …) as well as non-nutritive phytochemicals (phenolic compounds, flavonoids, bioactive peptides, …) content of these types of foods. Fermented fruit or vegetable products are part of various diets worldwide. Lactic acid bacteria (LAB) fermentation is common among the various fermentation processes used. It produces changes in both profile and types of bioactive compounds. Molecules such as bioactive peptides, short chain fatty acids or polysaccharides are generated while sugar content or anti-nutritional compounds are decreased and phenolic compounds are converted to molecules with added biological value. These transformations, associated with prebiotic and/or probiotic potential supply as well as improvement of food components bioaccessibility and bioavailability, result in modifications of health-related properties. Lastly, interactions between ingested fermented food, intestinal microbiota and their correlations to metabolomics profiles and health represent an important perspective deserving to be further explored.

Evaluation of nutritional and antioxidant properties of the tropical fruits banana, litchi, mango, papaya, passion fruit and pineapple cultivated in Réunion French Island.

Much attention is paid to the beneficial action of fruits against obesity-related oxidative stress. This study evaluated nutritional and antioxidant properties of banana, litchi, mango, papaya, passion fruit and pineapple from Réunion French Island. Results showed that total amounts of carbohydrates, vitamin C and carotenoids were 7.7-67.3g glucose equivalent, 4.7-84.9mg ascorbic acid equivalent and 26.6-3829.2µg ß-carotene equivalent/100g fresh weight, respectively. Polyphenols were detected as the most abundant antioxidants (33.0-286.6mg gallic acid equivalent/100g fresh weight) with the highest content from passion fruit. UPLC-MS analysis led to identify epigallocatechin and quercetin derivatives from banana and litchi, ferulic, sinapic, syringic and gallic acids from pineapple and mango, and piceatannol from passion fruit. Polyphenol-rich extracts protected red blood cells and preadipose cells against oxidative stress. Altogether, these findings highlight nutritional benefits of French tropical fruits and their possible interest to improve antioxidant capacities of the body during obesity.

Curcuma longa polyphenols improve insulin-mediated lipid accumulation and attenuate proinflammatory response of 3T3-L1 adipose cells during oxidative stress through regulation of key adipokines and antioxidant enzymes.

Plant polyphenols may exert beneficial action against obesity-related oxidative stress and inflammation which promote insulin resistance. This study evaluated the effect of polyphenols extracted from French Curcuma longa on 3T3-L1 adipose cells exposed to H2 O2 -mediated oxidative stress. We found that Curcuma longa extract exhibited high amounts of curcuminoids identified as curcumin, demethoxycurcumin, and bisdemethoxycurcumin, which exerted free radical-scavenging activities. Curcuma longa polyphenols improved insulin-mediated lipid accumulation and upregulated peroxisome proliferator-activated receptor-gamma gene expression and adiponectin secretion which decreased in H2 O2 -treated cells. Curcuminoids attenuated H2 O2 -enhanced production of pro-inflammatory molecules such as interleukin-6, tumor necrosis factor-alpha, monocyte chemoattractant protein-1, and nuclear factor κappa B. Moreover, they reduced intracellular levels of reactive oxygen species elevated by H2 O2 and modulated the expression of genes encoding superoxide dismutase and catalase antioxidant enzymes. Collectively, these findings highlight that Curcuma longa polyphenols protect adipose cells against oxidative stress and may improve obesity-related metabolic disorders. © 2016 BioFactors, 42(4):418-430, 2016.

Dietary polyphenols preconditioning protects 3T3-L1 preadipocytes from mitochondrial alterations induced by oxidative stress.

Numerous studies indicate that an increase in reactive oxygen species (ROS) significantly affects white adipose tissue biology and leads to an inflammatory profile and insulin resistance, which could contribute to obesity-associated diabetes and cardiovascular diseases. Mitochondria play a key role in adipose tissue energy metabolism and constitute the main source of cellular ROS such as H(2)O(2). Polyphenols constitute the most abundant antioxidants provided by the human diet. Indeed, they are widely distributed in fruits, vegetables and some plant-derived beverages such as coffee and tea. Thus, the biological effects of dietary polyphenols that may increase the antioxidant capacity of the body against obesity-induced oxidative stress are of high interest. Here, we studied the capacity of polyphenols to modulate the impact of oxidative stress on the mitochondria of preadipocytes, which are important cells governing the adipose tissue development for energy homeostasis. Whereas H(2)O(2) treatment induces a proliferation arrest associated with an increase in mitochondrial content in 3T3-L1 preadipocytes, preconditioning with some major dietary polyphenols totally or partially protects the cells against oxidative stress consequences. This article is part of a Directed Issue entitled: Bioenergetic dysfunction, adaptation and therapy.