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The search for new antimalarial chemotherapy has become increasingly urgent due to parasite resistance to current drugs. Ellagic acid (EA) is a polyphenol, recently found in various plant products, that has effective antimalarial activity in vitro and in vivo without toxicity. To further understand the antimalarial mechanism of action of EA in vitro, we evaluated the effects of EA, ascorbic acid and N-acetyl-L-cysteine (NAC), alone and/or in combination on the production of reactive oxygen species (ROS) during the trophozoite and schizonte stages of the erythrocytic cycle of P. falciparum. The parasitized erythrocytes were pre-labelled with DCFDA (dichlorofluorescein diacetate). We showed that NAC had no effect on ROS production, contrary to ascorbic acid and EA, which considerably reduced ROS production. Surprisingly, EA reduced the production of the ROS with concentrations (6.6x10-9 - 6.6x10-6 M) ten-fold lower than ascorbic acid (113x10-6 M). Additionally, the in vitro drug sensitivity of EA with antioxidants showed that antiplasmodial activity is independent of the ROS production inside parasites, which was confirmed by the additive activity of EA and desferrioxamine. Finally, EA could act by reducing the glutathione content inside the Plasmodium parasite. This was consolidated by the decrease in the antiplasmodial efficacy of EA in the murine model Plasmodium yoelii- high GSH strain, known for its high glutathione content. Given its low toxicity and now known mechanism of action, EA appears as a promising antiplasmodial compound. [ABSTRACT FROM AUTHOR]

Modified urinary fluid shear stress (FSS) induced by variations of urinary fluid flow and composition is observed in early phases of most kidney diseases. Recently, we reported that renal tubular FSS promotes endothelial cell activation and subsequent adhesion of human monocytes, thereby suggesting that changes in urinary FSS can induce the development of inflammation (Miravète M, Klein J, Besse-Patin A, Gonzalez J, Pecher C, Bascands JL, Mercier-Bonin M, Schanstra JP, Buffin- Meyer B, BBRC 407: 813-817, 2011). Here, we evaluated the influence of tubular FSS on monocytes as they play an important role in the progression of inflammation in nephropathies. Human renal tubular cells (HK-2) were exposed to FSS 0.01 Pa for 30 min or 5 h. Treatment of human THP-1 monocytes with the resulting conditioned medium (FSS-CM) modified the expression of macrophage differentiation markers, suggesting differentiation toward the inflammatory M1-type macrophage. The effect was confirmed in freshly isolated human monocytes. In contrast to endothelial cells, the activation of monocytes by FSS-CM did not require TNF-α. Cytokine array analysis of FSS-CM showed that FSS modified secretion of cytokines by HK-2 cells, particularly by increasing secretion of TGF-β and by decreasing secretion of C-C chemokine ligand 2 (CCL2). Neutralization of TGF-β or CCL2 supplementation attenuated the effect of FSS-CM on macrophage differentiation. Finally, FSS-injured HK-2 cells expressed and secreted early biomarkers of tubular damage such as kidney injury molecule 1 and neutrophil gelatinase-associated lipocalin. In conclusion, changes in urinary FSS should now also be considered as potential insults for tubular cells that initiate/perpetuate interstitial inflammation. [ABSTRACT FROM AUTHOR]

Limited data exist on the cytokine and cellular changes in the alveolar environment in immunocompromised patients during Pneumocystis jirovecii infection. A cellular and a cytokine analysis were performed on bronchoalveolar lavage (BAL) samples from three groups of patients, i.e., an initial study group of 64 immunocompromised P. jirovecii-positive individuals and two control groups of P. jirovecii-negative patients who had been or not immunosuppressed (65 patients). The results were related to alveolar dilution as determined by urea measurement. Compared with non-infected groups, P. jirovecii-infected patients had a lower level of alveolar macrophages (AM), particularly those with high burdens of P. jirovecii. Alveolar macrophages over-expressed the Dectin-1 receptor, which was largely implicated in P. jirovecii clearance. The alveolar CD8+T and CD4+T lymphocyte counts were increased and an inverse correlation was observed between the alveolar CD4+ cell count and the P. jirovecii burden. Although the alveolar IL-6 level was considerably increased, alveolar IL-17, IL-10, TNF-α, TGF-β concentrations of P. jirovecii patients were not different from the control groups. Changes in the pulmonary environment were also highlighted during P. jirovecii colonization. Our study suggests that there is a correlation between the P. jirovecii burden in the alveolus (from colonization to a high P. jirovecii burden), and the degree of impairment of the alveolar immune response. [ABSTRACT FROM AUTHOR]

Background: The activity of promising anti-malarial drugs against Plasmodium gametocytes is hard to evaluate even in vitro. This is because visual examination of stained smears, which is commonly used, is not totally convenient. In the current study, flow cytometry has been used to study the effect of established anti-malarial drugs against sexual stages obtained from W2 strain of Plasmodium falciparum. Gametocytes were treated for 48 h with different drug concentrations and the gametocytaemia was then determined by flow cytometry and compared with visual estimation by microscopy. Results and conclusions: Initially gametocytaemia was evaluated either using light microscopy or flow cytometry. A direct correlation (r2 = 0.9986) was obtained. Two distinct peaks were observed on cytometry histograms and were attributed to gametocyte populations. The activities of established anti-malarial compounds were then measured by flow cytometry and the results were equivalent to those obtained using light microscopy. Primaquine and artemisinin had IC50 of 17.6 μM and 1.0 μM, respectively. Gametocyte sex was apparently distinguishable by flow cytometry as evaluated after induction of exflagellation by xanthurenic acid. These data form the basis of further studies for developing new methods in drug discovery to decrease malaria transmission. [ABSTRACT FROM AUTHOR]

Toxoplasmosis is a healthcare problem in pregnant women and immunocompromised patients. Like humans, rats usually develop a subclinical chronic infection. LEW rats exhibit total resistance to Toxoplasma gondii infection, which is expressed in a dominant mode. A genome-wide search carried out in a cohort of F2 progeny of susceptible BN and resistant LEW rats led to identify on chromosome 10 a major locus of control, which we called Toxo1. Using reciprocal BN and LEW lines congenic for chromosome 10 genomic regions from the other strain, Toxo1 was found to govern the issue of T. gondii infection whatever the remaining genome. Analyzes of rats characterized by genomic recombination within Toxo1, reduced the interval down to a 1.7-cM region syntenic to human 17p13. In vitro studies showed that the Toxo 1-mediated refrefracto-riness to T. gondii infection is associated with the ability of the macrophage to impede the proliferation of the parasite within the parasitophorous vacuole. In contrast, proliferation was observed in fibroblasts whatever the genomic origin of Toxo1. Furthermore, ex vivo studies indicate that macrophage controls parasitic infection spreading by a Toxo1-mediated mechanism. This forward genetics approach should ultimately unravel a major pathway of innate resistance to toxoplasmosis and possibly to other apicomplexan parasitic diseases. [ABSTRACT FROM AUTHOR]

We studied the effects of interferon-γ (IFN-γ), a Th1 cytokine, and interleukin-13 (IL-13) or interleukin-4 (IL-4), Th2 cytokines, on the antifungal activity of resident murine peritoneal macrophages against Candida albicans ‘in vitro’. IFN-γ, IL-13 and IL-4 treatment enhanced the candidastatic functions of the macrophages. Reactive oxygen intermediates (ROIs) seem to be directly involved in the increase of anti-Candida activity in macrophages treated with Th1 or Th2 cytokines. Study of unopsonized C. albicans phagocytosis showed that IFN-γ reduces the uptake process whereas the Th2 cytokines increase it. This difference is correlated to mannose receptor expression, which is decreased by IFN-γ but increased by the Th2 cytokines. So, the effects on phagocytosis and candidastatic activity of IFN-γ-treated macrophages are dissociated. In contrast, the phagocytic ability of macrophages pretreated ‘in vitro’ with IL-4 or IL-13 played a complementary role to the ROIs, in reduction of yeast proliferation by macrophages. In consequence, the macrophages treated with IL-13 and IL-4 develop a higher fungistatic activity than macrophages activated by IFN-γ. Amphotericin B associated with IL-13 or IFN-γ, but not with IL-4, enhanced the yeast growth inhibition activity of macrophages. The ROIs were involved in the additive effect of IFN-γ with amphotericin B, whereas another mechanism was implicated in the increase of candidastatic activity of macrophages treated with IL-13 in association with amphotericin B. [ABSTRACT FROM PUBLISHER]

We show that lipopolysaccharide-free actetylated low-density lipoprotein (LDL), but not native LDL, stimulates tumor-necrosis factor-α (TNF-α) secretion by rat peritoneal macrophages and the signal-transduction pathways involved. The role of the scavenger receptor (SR) in this response was suggested by the absence of an effect induced by native LDL, signal coupling involving pertussis-toxin-dependent guanine-nucleotide-binding regulatory (G) protein, and the complete inhibition of this response by SR ligands [poly(I) and dextran sulfate]. Acetylated LDL induces rapid Ca2+ release from inositol-phosphate-sensitive Ca2+ stores mediated by pertussis-sensitive G proteins and a sustained Ca2+ rise mediated by Ca2+ influx and by Ca2+ release from ryanodine-sensitive Ca2+ stores. Acetylated LDL-induced Ca2+ influx and TNF-α production were abolished by inhibitors of phospholipase C (U73122) and phospholipase A2 (bromophenacyl bromide), but were not affected by an inhibitor of protein kinase C (calphostine C). Therefore, Ca2+ influx induced by acetylated LDL is dependent on Ca2+ store depletion. Arachidonate released by acetylated LDL acts as a second messenger to activate TNF-α secretion via Ca2+ influx. While the Ca2+ signal was not modified by an inhibitor of protein tyrosine kinases (PTK; herbimycin A), this inhibitor completely blocked TNF-α production, suggesting the involvement of PTK downstream of the Ca2+ signal. These results suggest that a sustained elevation of intracellular Ca2+, mediated through Ca2+ influx via the phospholipase-A2-dependent pathway, is essential for induction of TNF-α secretion. The type of SR class involved in these pathways remains to be identified. [ABSTRACT FROM AUTHOR]

A retrospective study was done on 66 diabetic patients who had renal biopsies performed during 1979–1994. This review shows 10 patients who presented IgA nephropathy associated with diabetic nephropathy. Six patients had insulin-dependent diabetes mellitus and 4 patients non-insulin-dependent diabetes mellitus. All patients presented with proteinuria and 7 had hematuria. Four patients presented with renal impairment. Histologic evaluation disclosed the presence of thickened glomerular basement membranes and increased mesangial matrix in all cases, associated with nodular sclerosis in 8 cases. By immunofluorescence, diffuse mesangial IgA deposits were observed in all cases. The high incidence of the coexistence of IgA nephropathy and diabetes seems not merely coincidental. Structural and/or functional abnormalities of the glomerular basement membranes might facilitate the development of immune complex glomerular diseases. In patients with diabetes, the appearance of urinary abnormalities and/or deterioration in renal function altered the clinical history of diabetic nephropathy. The disorders are clinically suggestive of the presence of nondiabetic renal disease and raised the possibility of another pathogenetic mechanism. [ABSTRACT FROM AUTHOR]

Candida albicans produces a complex glycosphingolipid called phospholipomannan (PLM), which is present on the cell-wall surface of yeast and shed upon contact with host cells. The glycan moiety of PLM is composed of β-mannosides with degrees of polymerization up to 19 in C. albicans serotype A. PLM from serotype B strains displays a twofold decrease in the length of the glycan chains. In this study we compared the proinflammatory activities of PLMs purified from C. albicans serotype A and serotype B strains and from a bmt6Δ mutant of C. albicans, whose PLM is composed of short truncated oligomannosidic chain. We found that PLMs activate caspase-1 in murine macrophage cell line J774 independent of the glycan chain length although IL-1β secretion is more intense with long glycan chain. None of the tested PLMs stimulate ROS production, indicating that caspase-1 activation may occur through a ROS-independent pathway. On the other hand, only long-chain oligomannosides present on PLM from serotype A strain (PLM-A) are able to induce TNF-α production in macrophages, a property that is not affect by blocking endocytosis through latrunculin A treatment. Finally, we demonstrate that soluble and not cell surface-bound galectin-3, is able to potentiate PLM-A-induced TNF-α production in macrophages. PLMs from C. albicans serotype B and from bmt6∆ mutant are not able to induce TNF-α production and galectin-3 pretreatment does not interfere with this result. In conclusion, we show here that PLMs are able to evoke a proinflammatory state in macrophage, which is in part dependent on their glycosylation status. Long-glycan chains favor interaction with soluble galectin-3 and help amplify inflammatory response. [ABSTRACT FROM AUTHOR]

Exposure to pesticides through eyes, skin, ingestion and inhalation may affects human health by interfering with immune cells, such as macrophages. We evaluated, in vitro , the effect of six pesticides widely used in apple arboriculture on the functions of human monocyte-derived macrophages (hMDMs). hMDMs were cultured for 4 or 24 h with or without pesticides (0.01, 0.1, 1, 10 μmol.L-1). We showed that chlorpyrifos, thiacloprid, thiophanate, boscalid, and captan had little toxic effect at the tested concentrations, while dithianon had low-cytotoxicity at 10 μmol.L−1. While boscalid showed no effect on hMDMs function, thiophanate (0.01 μmol.L−1) stimulated with TPA and thiacloprid (1, 10 μmol.L−1) stimulated with zymosan activated ROS production. Chlorpyrifos, dithianon, and captan inhibited ROS production and TNF-α, IL-1β pro-inflammatory cytokines. We established that dithianon (0.01–1 μmol.L−1) and captan (0.1, 1 μmol.L−1) induced mRNA expression of NQO1 and HMOX1 antioxidant enzymes. Dithianon also induced the mRNA expression of catalase, superoxide dismutase-2 at 10 μmol.L−1. Together, these results show that exposure to chlorpyrifos, dithianon, and captan induce immunomodulatory effects that may influence the disease fighting properties of monocytes/macrophages while pesticides such as thiacloprid, thiophanate and boscalid have little influence. • CPF, DIT inhibited ROS production via PKC-dependent and PKC-independent pathways. • CAP inhibited ROS production triggered via PKC. • CPF, DIT, CAP inhibited the production of TNF-α, IL-1β inflammatory response to LPS. • CAP, DIT increased mRNA level of antioxidant enzymes suggesting an oxidative stress. • Exposure to CPF, DIT, CAP may compromise innate immune responses to infection. [ABSTRACT FROM AUTHOR]

Summary: Macrophages act as the primary effector cells during Leishmania infection through production of reactive oxygen species (ROS) and interleukin-1β (IL-1β). However, how macrophage-killing mechanisms are activated during Leishmania-macrophage interactions is poorly understood. Here, we report that the macrophage response against Leishmania infantum in vivo is characterized by an M2b-like phenotype and C-type lectin receptors (CLRs) signature composed of Dectin-1, mannose receptor (MR), and the DC-SIGN homolog SIGNR3 expression. Dectin-1 and MR were crucial for the microbicidal response as indicated by the fact that they activated Syk-p47phox and arachidonic acid (AA)-NADPH oxidase signaling pathways, respectively, needed for ROS production and also triggered Syk-coupled signaling for caspase-1-induced IL-1β secretion. In contrast, SIGNR3 has divergent functions during Leishmania infantum pathogenesis; this CLR favored parasite resilience through inhibition of the LTB4-IL-1β axis. These pathways also operated during infection of primary human macrophages. Therefore, our study promotes CLRs as potential targets for treatment, diagnosis, and prevention of visceral leishmaniasis. [Copyright &y& Elsevier]

Abstract: Nanocrystalline calcium phosphate apatites constitute the mineral part of hard tissues, and the synthesis of biomimetic analogs is now well-mastered at the lab-scale. Recent advances in the fine physico-chemical characterization of these phases enable one to envision original applications in the medical field along with a better understanding of the underlying chemistry and related pharmacological features. In this contribution, we specifically focused on applications of biomimetic apatites in the field of cancer diagnosis or treatment. We first report on the production and first biological evaluations (cytotoxicity, pro-inflammatory potential, internalization by ZR-75-1 breast cancer cells) of individualized luminescent nanoparticles based on Eu-doped apatites, eventually associated with folic acid, for medical imaging purposes. We then detail, in a first approach, the preparation of tridimensional constructs associating nanocrystalline apatite aqueous gels and drug-loaded pectin microspheres. Sustained releases of a fluorescein analog (erythrosin) used as model molecule were obtained over 7 days, in comparison with the ceramic or microsphere reference compounds. Such systems could constitute original bone-filling materials for in situ delivery of anticancer drugs. [Copyright &y& Elsevier]

Abstract: For the effective induction of a hapten-specific T cell immune response toward contact sensitizers, in addition to covalent-modification of skin proteins, the redox and inflammatory statuses of activated dendritic cells are crucial. The aim of this study was to better understand how sensitizers modulate an inflammatory response through cytokines production and COX metabolism cascade. To address this purpose, we used the human monocytic-like U-937 cell line differentiated by phorbol myristate acetate (PMA) and investigated the effect of 6 contact sensitizers (DNCB, PPD, hydroquinone, propyl gallate, cinnamaldehyde and eugenol) and 3 non sensitizers (lactic acid, glycerol and tween 20) on the production of pro-inflammatory cytokines (IL-1β and TNF-α) and on the arachidonic acid metabolic profile after bacterial lipopolysaccharide (LPS) stimulation. Our results showed that among the tested molecules, all sensitizers specifically prevent the production of PMA/LPS-induced COX-2 metabolites (PGE2, TxB2 and PGD2), eugenol and cinnamaldehyde inhibiting also the production of IL-1β and TNF-α. We further demonstrated that there is no unique PGE2 inhibition mechanism: while the release of arachidonic acid (AA) from membrane phospholipids does not appear do be a target of modulation, COX-2 expression and/or COX-2 enzymatic activity are the major steps of prostaglandin synthesis that are inhibited by sensitizers. Altogether these results add a new insight into the multiple biochemical effects described for sensitizers. [Copyright &y& Elsevier]

Abstract: Th1 cytokines and microbial lipopolysaccharides (LPS) activate macrophages to produce inflammatory mediators and effector molecules. Althrough Th2 cytokines often have an opposite action to Th1 cytokines and down-modulate the inflammatory response of macrophages, they can induce a distinct alternative activation that is beneficial in host defence. In this study, we report that IL-13 enhances the anti-Toxoplasma activity of LPS-activated murine macrophages. The inhibition of parasite proliferation was not related to reduced Toxoplasma gondii penetration into the cells, nor to the conversion of tachyzoites into bradyzoites. Used alone, IL-13 triggers the polarisation of macrophages towards type 2. However, in LPS-activated macrophages, we show the priming capacity of this cytokine to enhance the expression of inducible nitric oxide synthase (iNOS), a major marker of type 1 macrophages. This effect of IL-13 was not dependent on the activation state of macrophages (resident versus thioglycolate-elicited) or the timing of pre-treatment. We demonstrate a correlation between the enhancement of NO production and upgrading of the microbicidal effectiveness of the macrophages. Thus, both Th2 and Th1 cytokines could activate macrophages to control infections. [Copyright &y& Elsevier]

Abstract: Th2 cytokines such as interleukin-13 (IL-13) have both, stimulatory and inhibitory effects on effector functions of macrophages. Reactive nitrogen species are classicaly induced in Th1 cytokines and/or lipopolysaccharides (LPS) activated macrophages and this response is inhibited by IL-13. In contrast, IL-13 primes macrophages to produce NO in response to LPS when IL-13 treatment happens prior to LPS exposure. This mechanism occurs through a complex signalling pathway, which involves the scavenger receptor CD36, the LPS receptor CD14 and the nuclear receptor PPARγ. The enhancement of NO production is the consequence of iNOS induction at mRNA and protein levels. The increase of the NO production induced by LPS in IL-13 pre-treated macrophages is found to potentiate the inhibition of Toxoplasma gondii intracellular replication. These results reveal a novel IL-13 signalling pathway that primes the antimicrobial activity of macrophages induced by LPS caused by overexpression of the iNOS-NO axis. [Copyright &y& Elsevier]

We investigated the immunohistochemical distribution of active NF-κB p65 and peroxisome proliferator-activated receptor (PPAR) subtypes alpha and gamma in the different phases of liver steatonecrosis and cirrhosis induced in rats after 3 and 9 weeks of carbon tetrachloride (CCl4) intoxication. CCl4 treatment can induce changes in the expression of NF-κB and PPARs. Immunohistochemical analysis of liver tissue sections from rats with steatonecrosis or cirrhosis demonstrated a significant increase in the number of NF-κB-positive and TNF-α-positive hepatocytes and Kupffer cells. In healthy controls, no expression of active NF-κB was detected. In previous studies, we have demonstrated that Kupffer cells isolated from rats with CCl4-induced steatonecrosis produced more reactive oxygen intermediates than cells isolated from normal rats. These oxidants could activate NF-κB and lead to an overexpression of TNF-α, observed in liver tissue sections. After CCl4 ingestion, the rat livers demonstrated a significantly decreased number of hepatocytes expressing PPARα and PPARγ and a significantly increased number of ED2-positive Kupffer cells expressing these transcription factors, compared to normal. The activation of the p65 isoform of NF-κB correlates negatively with transcription of the alpha and gamma isoforms of PPAR in hepatocytes, and positively in Kupffer cells. These results suggest that the regulation and the role of these two transcription factors differ in the two cell types studied. [ABSTRACT FROM AUTHOR]

Macrophage mannose receptor (MMR) is an important component of the innate immune system implicated in host defense against microbial infections such as candidiasis and in antigen presentation. We demonstrate here that the MMR expression is induced in mouse peritoneal macrophages following exposure to PPARγ ligands or to interleukine-13 (IL-13) via a PPARγ signaling pathway. Ligand activation of the PPARγ in macrophages promotes uptake, killing of Candida albicans, and reactive oxygen intermediates production triggered by the yeasts through MMR overexpression. We also show that MMR induction by IL-13 via PPARγ is dependent on phopholipase A2 activation and that IL-13 induces 15d-PGJ2 production and nuclear localization. These results reveal a novel signaling pathway controlling the MMR surface expression and suggest that endogenous PPARγ ligand produced by phospholipase A2 activation may be an important regulator of MMR expression by IL-13. [Copyright &y& Elsevier]

: ObjectivesReactive oxygen species may be involved in the pathogenesis of chronic hepatitis C virus infection. Metallothionein (MT) is an essential protein for the protection of cells against reactive oxygen species. The aim of this prospective study was to assess the influence of the hepatic level and cellular distribution of MT in hepatitis C virus (HCV) infection and in the liver disease outcome.: MethodsIn liver biopsy samples of 32 patients with chronic HCV infection and of 12 control subjects, quantification of MT was performed by radioimmunoassay, MT, interleukin (IL)-1 and -6, and tumor necrosis factor (INF)–α mRNA by reverse transcription–polymerase chain reaction (PCR) and cellular distribution by immunohistochemistry.: ResultsIn HCV-infected patients, MT liver protein level was 3-fold lower than in control specimens. A significant inverse linear regression between MT protein or mRNA expression and the Histological Activity Index, the necroinflammatory grade, and the stage of fibrosis was observed. MT immunostaining was located in the nucleus and cytoplasm in hepatocytes of control subjects, whereas it was mainly cytoplasmic in HCV-infected patients. Before interferon (IFN) therapy, the hepatic MT level in patients that were nonsustained responders was half that of sustained responders. Intrahepatic IL-6 and MT were simultaneously down-regulated, but no correlation was found between MT and intrahepatic cytokine mRNA expression in patients with chronic HCV infection.: ConclusionsThis study shows that hepatic MT expression could reflect the severity of chronic HCV infection and could be one of the factors associated with a favorable clinical outcome in the response to interferon therapy. [Copyright &y& Elsevier]

Background/Aims: Chronic infection with hepatitis C virus leads to liver cirrhosis and hepatocellular carcinoma. Hepatocellular carcinoma is sometimes associated with p53 dysfunction and decreased p21WAF1 expression. The p21WAF1 gene is a major target of p53, and p21WAF1 protein regulates the activities of cyclin/CDK complexes involved in cell cycle control and tumor formation. Because core protein has oncogenic properties, we investigated the expression of p21WAF1 following core expression.Methods: We analyzed by Western blot, Northern blot and transfection the expression of p21WAF1 in HepG2 cell line under transient expression of Hepatitis C core protein by recombinant-adenoviral infection.Results and discussion: Infection of HepG2 with core-encoding viruses induced the down-regulation of p21WAF1 expression. This effect is due to a decrease in the p21WAF1 gene transcription and of the p21WAF1 protein half-life. These results support a role for Hepatitis C virus core protein in cell transformation. We also found also that the transforming growth factor β can counteract the core-induced p21WAF1 down-regulation. The antagonist effect of TGF β, or of other molecules, on p21WAF1 expression may be of particular interest for the treatment of HCV-positive hepatocellular carcinoma. [Copyright &y& Elsevier]

Simple Summary: AMHRII, the anti-Müllerian hormone receptor, is selectively expressed in normal sexual organs in healthy adults but is also re-expressed in ovarian, colorectal and lung cancers. In this context, we developed murlentamab, a humanized glyco-engineered anti-AMHRII monoclonal antibody, currently in clinical trial. Preliminary data suggest that murlentamab anti-tumor activity involves immune response activation. Thus, in vitro experiments were performed to precisely characterize the murlentamab effect on the human immune system. We show that murlentamab treatment is associated with evidences of innate and adaptive immune cell activation in cancer patient samples. Moreover, we demonstrate that the murlentamab opsonization of AMHRII-expressing ovarian tumor cells promotes a polarization switch of both naïve and tumor-associated macrophages towards an anti-tumor M1-like phenotype. Our work also supports that, through macrophage reeducation, murlentamab activates an anti-tumor adaptive immune response. Finally, the combination of murlentamab with pembrolizumab confirmed novel clinical perspectives of murlentamab association with checkpoint inhibitors and other immuno-modulators. AMHRII, the anti-Müllerian hormone receptor, is selectively expressed in normal sexual organs but is also re-expressed in gynecologic cancers. Hence, we developed murlentamab, a humanized glyco-engineered anti-AMHRII monoclonal antibody currently in clinical trial. Low-fucosylated antibodies are known to increase the antibody-dependent cell-mediated cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP) potency of effector cells, but some preliminary results suggest a more global murlentamab-dependent activation of the immune system. In this context, we demonstrate here that the murlentamab opsonization of AMHRII-expressing ovarian tumor cells, in the presence of unstimulated- or tumor-associated macrophage (TAM)-like macrophages, significantly promotes macrophage-mediated ADCC and shifts the whole microenvironment towards a pro-inflammatory and anti-tumoral status, thus triggering anti-tumor activity. We also report that murlentamab orients both unstimulated- and TAM-like macrophages to an M1-like phenotype characterized by a strong expression of co-stimulation markers, pro-inflammatory cytokines and chemokines, favoring T cell recruitment and activation. Moreover, we show that murlentamab treatment shifts CD4+ Th1/Th2 balance towards a Th1 response and activates CD8+ T cells. Altogether, these results suggest that murlentamab, through naïve macrophage orientation and TAM reprogrammation, stimulates the anti-tumor adaptive immune response. Those mechanisms might contribute to the sustained clinical benefit observed in advanced cancer patients treated with murlentamab. Finally, the enhanced murlentamab activity in combination with pembrolizumab opens new therapeutic perspectives. [ABSTRACT FROM AUTHOR]

Inhibition of regeneration and induction of tissue fibrosis are classic outcomes of tissue repair in adult mammals. Here, using a newly developed model of regeneration in adult mammals i.e. regeneration after massive resection of an inguinal fat pad, we demonstrate that both endogenous and exogenous opioids prevent tissue regeneration in adults, by inhibiting the early production of reactive oxygen species (ROS) that generally occurs after lesion and is required for regeneration. These effects can be overcome and regeneration induced by the use of an opioid antagonist. The results obtained in both our new model and the gold standard adult zebrafish demonstrate that this mechanism can be considered as a general paradigm in vertebrates. This work clearly demonstrates that ROS is required for tissue regeneration in adult mammals and shows the deleterious effect of opioids on tissue regeneration through the control of this ROS production. It thus raises questions about opioid-based analgesia in perioperative care. [ABSTRACT FROM AUTHOR]

Cerebral malaria (CM) is one of the most severe forms of malaria and is a neuropathology that can lead to death. Monocytes have been shown to accumulate in the brain microvasculature at the onset of neurological symptoms during CM. Monocytes have a remarkable ability to adapt their function to their microenvironment from pro-inflammatory to resolving activities. This study aimed to describe the behavior of monocyte subpopulations during infection and its resolution. C57BL/6 mice were infected with the Plasmodium berghei ANKA strain and treated or not with chloroquine (CQ) on the first day of the onset of neurological symptoms (day 6) for 4 days and followed until day 12 to mimic neuroinflammation and its resolution during experimental CM. Ly6C monocyte subpopulations were identified by flow cytometry of cells from the spleen, peripheral blood, and brain and then quantified and characterized at different time points. In the brain, the Ly6C int and Ly6C low monocytes were associated with neuroinflammation, while Ly6C hi and Ly6C int were mobilized from the peripheral blood to the brain for resolution. During neuroinflammation, CD36 and CD163 were both involved via splenic monocytes, whereas our results suggest that the low CD36 expression in the brain during the neuroinflammation phase was due to degradation. The resolution phase was characterized by increased expressions of CD36 and CD163 in blood Ly6C low monocytes, a higher expression of CD36 in the microglia, and restored high expression levels of CD163 in Ly6C hi monocytes localized in the brain. Thus, our results suggest that increasing the expressions of CD36 and CD163 specifically in the brain during the neuroinflammatory phase contributes to its resolution., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Royo, Camara, Bertrand, Batigne, Coste, Pipy, Aubouy and the NeuroCM Group.)

Patients with diabetes present a persistent inflammatory process, leading to impaired wound healing. Since nonhealing diabetic wound management shows limited results, the introduction of advanced therapies targeting and correcting the inflammatory status of macrophages in chronic wounds could be an effective therapeutic strategy to stop the sustained inflammation and to return to a healing state. In an excisional skin injury in a diet-induced diabetic murine model, we demonstrate that topical administration of low-dose aspirin (36 μg/wound/day) improves cutaneous wound healing by increasing wound closure through the promotion of the inflammation resolution program of macrophages. This treatment increased efferocytosis of wound macrophages from aspirin-treated diabetic mice compared with untreated diabetic mice. We also show that aspirin treatment of high-fat-fed mice oriented the phenotype of wound macrophages toward an anti-inflammatory and proresolutive profile characterized by a decrease of LTB4 production. The use of diabetic mice deficient for 5-LOX or 12/15-LOX demonstrated that these two enzymes of acid arachidonic metabolism are essential for the beneficial effect of aspirin on wound healing. Thus, aspirin treatment modified the balance between pro- and anti-inflammatory eicosanoids by promoting the synthesis of proresolving LXA4 through 5-LOX, LTA4, 12/15-LOX signaling. In conclusion, the restoration of an anti-inflammatory and proresolutive phenotype of wound macrophages by the topical administration of low-dose aspirin represents a promising therapeutic approach in chronic wounds., (© 2022 by the American Diabetes Association.)

Ziram, a zinc dithiocarbamate is widely used worldwide as a fungicide in agriculture. In order to investigate ziram-induced changes in macrophage functions and polarization, human monocytes-derived macrophages in culture were treated with ziram at 0.01-10 μmol.L -1 for 4-24 h. To characterize zinc involvement in these changes, we also determined the effects of disulfiram alone (dithiocarbamate without zinc) or in co-incubation with ZnSO 4 . We have shown that ziram and disulfiram at 0.01 μmol.L -1 increased zymosan phagocytosis. In contrast, ziram at 10 μmol.L -1 completely inhibited this phagocytic process, the oxidative burst triggered by zymosan and the production of TNF-α, IL-1β, IL-6, and CCL2 triggered by LPS. Disulfiram had the same effects on these macrophages functions only when combined with zinc (10 μmol.L -1 ). In contrast, at 10 μmol.L -1 ziram and zinc associated-disulfiram induced expression of several antioxidants genes HMOX1, SOD2, and catalase, which could suggest the induction of oxidative stress. This oxidative stress could be involved in the increase in late apoptosis induced by ziram (10 μmol.L -1 ) and zinc associated-disulfiram. Concerning gene expression profiles of membrane markers of macrophage polarization, ziram at 10 μmol.L -1 had two opposite effects. It inhibited the gene expression of M2 markers (CD36, CD163) in the same way as the disulfiram-zinc co-treatment. Conversely, ziram induced gene expression of other M2 markers CD209, CD11b, and CD16 in the same way as treatment with zinc alone. Disulfiram-zinc association had no significant effects on these markers. These results taken together show that ziram via zinc modulates macrophages to M2-like anti-inflammatory phenotype which is often associated with various diseases.