Showing papers by "Richard Bucala published in 2020"

Glioblastoma Myeloid-Derived Suppressor Cell Subsets Express Differential Macrophage Migration Inhibitory Factor Receptor Profiles That Can Be Targeted to Reduce Immune Suppression

Abstract: The application of tumor immunotherapy to glioblastoma (GBM) is limited by an unprecedented degree of immune suppression due to factors that include high numbers of immune suppressive myeloid cells, the blood brain barrier, and T cell sequestration to the bone marrow We previously identified an increase in immune suppressive myeloid-derived suppressor cells (MDSCs) in GBM patients, which correlated with poor prognosis and was dependent on macrophage migration inhibitory factor (MIF) Here we examine the MIF signaling axis in detail in murine MDSC models, GBM-educated MDSCs and human GBM We found that the monocytic subset of MDSCs (M-MDSCs) expressed high levels of the MIF cognate receptor CD74 and was localized in the tumor microenvironment In contrast, granulocytic MDSCs (G-MDSCs) expressed high levels of the MIF non-cognate receptor CXCR2 and showed minimal accumulation in the tumor microenvironment Furthermore, targeting M-MDSCs with Ibudilast, a brain penetrant MIF-CD74 interaction inhibitor, reduced MDSC function and enhanced CD8 T cell activity in the tumor microenvironment These findings demonstrate the MDSC subsets differentially express MIF receptors and may be leveraged for specific MDSC targeting

The "Infodemic" of COVID-19.

Abstract: Some in the medical publishing world have observed an "infodemic" occurring alongside the pandemic. One might define an infodemic as a contagious disease infecting our information culture. As the Editors of A&R, tasked with conducting, reviewing, reporting, and translating science to the rheumatic disease community, we agree with this diagnosis. Herein, we reflect on how the pandemic has impacted A&R, the medical publishing world, and how we may best engage our community to navigate current challenges.

Designed CXCR4 mimic acts as a soluble chemokine receptor that blocks atherogenic inflammation by agonist-specific targeting

Abstract: Targeting a specific chemokine/receptor axis in atherosclerosis remains challenging. Soluble receptor-based strategies are not established for chemokine receptors due to their discontinuous architecture. Macrophage migration-inhibitory factor (MIF) is an atypical chemokine that promotes atherosclerosis through CXC-motif chemokine receptor-4 (CXCR4). However, CXCR4/CXCL12 interactions also mediate atheroprotection. Here, we show that constrained 31-residue-peptides ('msR4Ms') designed to mimic the CXCR4-binding site to MIF, selectively bind MIF with nanomolar affinity and block MIF/CXCR4 without affecting CXCL12/CXCR4. We identify msR4M-L1, which blocks MIF- but not CXCL12-elicited CXCR4 vascular cell activities. Its potency compares well with established MIF inhibitors, whereas msR4M-L1 does not interfere with cardioprotective MIF/CD74 signaling. In vivo-administered msR4M-L1 enriches in atherosclerotic plaques, blocks arterial leukocyte adhesion, and inhibits atherosclerosis and inflammation in hyperlipidemic Apoe-/- mice in vivo. Finally, msR4M-L1 binds to MIF in plaques from human carotid-endarterectomy specimens. Together, we establish an engineered GPCR-ectodomain-based mimicry principle that differentiates between disease-exacerbating and -protective pathways and chemokine-selectively interferes with atherosclerosis.

CD74 Signaling Links Inflammation to Intestinal Epithelial Cell Regeneration and Promotes Mucosal Healing.

Abstract: Background & Aims The inflammatory response to intestinal damage promotes healing through mechanisms that are incompletely understood. Gene expression of cluster of differentiation 74 (CD74), the receptor for cytokine macrophage migration inhibitory factor, is increased in patients with inflammatory bowel disease (IBD), however, the role of CD74 signaling in intestinal inflammation remains poorly understood. The aim of this study was to determine the functional role of CD74 signaling in intestinal inflammation. Methods We studied the characteristics of CD74 protein expression in human IBD and experimental colitis. The functional role of CD74 signaling in the intestine was investigated using cellular models; wild-type, CD74-/-, and bone marrow chimera mice; neutralizing anti-CD74 antibodies; flow cytometry; immunohistochemistry; immunofluorescence; immunoblotting; and clustered regularly interspaced short palindromic repeats and associated protein 9 technology. Results In IBD patients and experimental colitis, CD74-receptor protein expression was increased in inflamed intestinal tissue, prominently in the crypt epithelial cells. By using distinct but complementary chemical and non–chemically induced mouse models of colitis with genetic and antibody neutralization approaches, we found that CD74 signaling was necessary for gut repair. Mechanistically, we found that the macrophage migration inhibitory factor cytokine, which also is increased in colitis, stimulated the CD74 receptor, enhancing intestinal epithelial cell proliferation through activation of the protein kinase B and the extracellular signal-regulated kinase pathways. Our data also suggest that CD74 signaling in immune cells was not essential for mucosal healing. Conclusions CD74 signaling is strongly activated during intestinal inflammation and protects the host by promoting epithelial cell regeneration, healing, and maintaining mucosal barrier integrity. Enhancing the CD74 pathway may represent a unique therapeutic strategy for promoting healing in IBD.

Differential regulation of macrophage activation by the MIF cytokine superfamily members MIF and MIF-2 in adipose tissue during endotoxemia.

Abstract: Sepsis is a leading cause of death worldwide and recent studies have shown white adipose tissue (WAT) to be an important regulator in septic conditions. In the present study, the role of the inflammatory cytokine macrophage migration inhibitory factor (MIF) and its structural homolog D-dopachrome tautomerase (D-DT/MIF-2) were investigated in WAT in a murine endotoxemia model. Both MIF and MIF-2 levels were increased in the peritoneal fluid of LPS-challenged wild-type mice, yet, in visceral WAT, the proteins were differentially regulated, with elevated MIF but downregulated MIF-2 expression in adipocytes. Mif gene deletion polarized adipose tissue macrophages (ATM) toward an anti-inflammatory phenotype while Mif-2 gene knockout drove ATMs toward a pro-inflammatory phenotype and Mif-deficiency was found to increase fibroblast viability. Additionally, we observed the same differential regulation of these two MIF family proteins in human adipose tissue in septic vs healthy patients. Taken together, these data suggest an inverse relationship between adipocyte MIF and MIF-2 expression during systemic inflammation, with the downregulation of MIF-2 in fat tissue potentially increasing pro-inflammatory macrophage polarization to further drive adipose inflammation.

CD74 knockout protects against LPS-induced myocardial contractile dysfunction through AMPK-Skp2-SUV39H1-mediated demethylation of BCLB.

Abstract: Background and purpose Lipopolysaccharides (LPS), an outer membrane component of Gram-negative bacteria, triggers myocardial anomalies in sepsis. Recent findings indicated a role for inflammatory cytokine MIF and its receptor, CD74, in septic organ injury, although little is known of the role of MIF-CD74 in septic cardiomyopathy. Experimental approach This study evaluated the impact of CD74 ablation on endotoxaemia-induced cardiac anomalies. Echocardiographic, cardiomyocyte contractile and intracellular Ca2+ properties were examined. Key results Our data revealed compromised cardiac function (lower fractional shortening, enlarged LV end systolic diameter, decreased peak shortening, maximal velocity of shortening/relengthening, prolonged duration of relengthening and intracellular Ca2+ mishandling) and ultrastructural derangement associated with inflammation, O2 - production, apoptosis, excess autophagy, phosphorylation of AMPK and JNK and dampened mTOR phosphorylation. These effects were attenuated or mitigated by CD74 knockout. LPS challenge also down-regulated Skp2, an F-box component of Skp1/Cullin/F-box protein-type ubiquitin ligase, while up-regulating that of SUV39H1 and H3K9 methylation of the Bcl2 protein BCLB. These effects were reversed by CD74 ablation. In vitro study revealed that LPS facilitated GFP-LC3B formation and cardiomyocyte defects. These effects were prevented by CD74 ablation. Interestingly, the AMPK activator AICAR, the autophagy inducer rapamycin and the demethylation inhibitor difenoconazole inhibited the effects of CD74 ablation against LPS-induced cardiac dysfunction, while the SUV39H1 inhibitor chaetocin or methylation inhibitor 5-AzaC ameliorated LPS-induced GFP-LC3B formation and cardiomyocyte contractile dysfunction. Conclusion and implications Our data suggested that CD74 ablation protected against LPS-induced cardiac anomalies, O2 - production, inflammation and apoptosis through suppression of autophagy in a Skp2-SUV39H1-mediated mechanism.

Molecular MRI of the Immuno-Metabolic Interplay in a Rabbit Liver Tumor Model: A Biomarker for Resistance Mechanisms in Tumor-targeted Therapy?

Abstract: Noninvasive molecular MRI can be used to visualize resistance mechanisms mediated by the tumor metabolism and immune evasion for strategic targeting by local-regional and immunotherapy in liver cancer.

Role of Host and Parasite MIF Cytokines during Leishmania Infection.

Abstract: Macrophage migration inhibitory factor (MIF) is an immunoregulatory cytokine that has been extensively characterized in human disease and in mouse models. Its pro-inflammatory functions in mammals includes the retention of tissue macrophages and a unique ability to counteract the immunosuppressive activity of glucocorticoids. MIF also acts as a survival factor by preventing activation-induced apoptosis and by promoting sustained expression of inflammatory factors such as TNF-α and nitric oxide. The pro-inflammatory activity of MIF has been shown to be protective against Leishmania major infection in mouse models of cutaneous disease, however the precise role of this cytokine in human infections is less clear. Moreover, various species of Leishmania produce their own MIF orthologs, and there is evidence that these may drive an inflammatory environment that is detrimental to the host response. Herein the immune response to Leishmania in mouse models and humans will be reviewed, and the properties and activities of mammalian and Leishmania MIF will be integrated into the current understandings in this field. Furthermore, the prospect of targeting Leishmania MIF for therapeutic purposes will be discussed.

Macrophage migration inhibitory factor promoter polymorphisms are associated with disease activity in rheumatoid arthritis patients from Southern Mexico.

Abstract: BACKGROUND Macrophage migration inhibitory factor (MIF) is a cytokine capable of stimulating inflammatory cytokine and matrix metalloproteinase production from macrophages and synovial fibroblasts, which leads to persistent inflammation and bone degradation, two of the major pathological processes in rheumatoid arthritis (RA). The aim of this study was to evaluate the association of MIF promoter polymorphisms (-794CATT5-8 rs5844572 and -173G > C, rs755622), circulating MIF levels, and mRNA expression with RA susceptibility and disease activity. METHODS A case-control study was conducted in 200 RA patients and 200 control subjects (CS) from Southern Mexico. Genotyping was performed by conventional PCR and PCR-RFLP methods. MIF mRNA expression was quantified by real-time PCR and MIF serum levels were determined by an ELISA kit. RESULTS The 7,7 (-794CATT5-8 ) and -173CC (-173G > C) genotypes were associated with higher disease activity in RA patients. MIF serum levels were increased, and MIF mRNA expression was reduced in RA patients as compared to CS. In addition, RA patients with moderate disease activity had higher MIF levels than those with low disease activity. The -794CATT5-8 and -173G > C MIF polymorphisms were not associated with RA susceptibility. CONCLUSION These results suggest an important role of MIF polymorphisms and MIF serum levels with disease activity in RA.

The Macrophage Migration Inhibitory Factor (MIF) Promoter Polymorphisms (rs3063368, rs755622) Predict Acute Kidney Injury and Death after Cardiac Surgery.

Abstract: Background: Macrophage Migration Inhibitory Factor (MIF) is highly elevated after cardiac surgery and impacts the postoperative inflammation. The aim of this study was to analyze whether the polymorphisms CATT5–7 (rs5844572/rs3063368,“-794”) and G>C single-nucleotide polymorphism (rs755622,-173) in the MIF gene promoter are related to postoperative outcome. Methods: In 1116 patients undergoing cardiac surgery, the MIF gene polymorphisms were analyzed and serum MIF was measured by ELISA in 100 patients. Results: Patients with at least one extended repeat allele (CATT7) had a significantly higher risk of acute kidney injury (AKI) compared to others (23% vs. 13%; OR 2.01 (1.40–2.88), p = 0.0001). Carriers of CATT7 were also at higher risk of death (1.8% vs. 0.4%; OR 5.12 (0.99–33.14), p = 0.026). The GC genotype was associated with AKI (20% vs. GG/CC:13%, OR 1.71 (1.20–2.43), p = 0.003). Multivariate analyses identified CATT7 predictive for AKI (OR 2.13 (1.46–3.09), p < 0.001) and death (OR 5.58 (1.29–24.04), p = 0.021). CATT7 was associated with higher serum MIF before surgery (79.2 vs. 50.4 ng/mL, p = 0.008). Conclusion: The CATT7 allele associates with a higher risk of AKI and death after cardiac surgery, which might be related to chronically elevated serum MIF. Polymorphisms in the MIF gene may constitute a predisposition for postoperative complications and the assessment may improve risk stratification and therapeutic guidance.

Genotyping Two Promoter Polymorphisms in the MIF Gene: A -794 CATT5-8 Microsatellite Repeat and a -173 G/C SNP.

Abstract: Macrophage migration inhibitory factor (MIF) is an upstream proinflammatory cytokine encoded by a functionally polymorphic locus. The promoter region of the human MIF gene contains two polymorphisms. A variable nucleotide tandem repeat at position -794 comprises five to eight CATT repeats (referred to henceforth by numbers from 5 to 8, rs5844572). Gene reporter assays show a proportional increase in transcription with CATT repeat number; the 5-repeat allele leads to low expression, and the 6-, 7-, and 8-repeat alleles lead to correspondingly higher expression of MIF. A second MIF promoter polymorphism comprises a G-to-C single nucleotide polymorphism (SNP) at position -173 (rs755622), which is in strong linkage disequilibrium with -794 7-CATT and is associated with arthritis clinical severity and higher serum and synovial fluid MIF levels. This allele also has been reported to confer improved survival in patients with outpatient pneumonia. In this chapter, we will introduce the methods of genotyping CATT5-8 repeats and the MIF -173 G/C from human samples.

Extracellular MIF, but not its homologue D-DT, promotes fibroblast motility independent of its receptor CD74/CD44.

Abstract: Macrophage migration inhibitory factor (MIF) and its homologue D-dopachrome tautomerase (D-DT) are ubiquitous, pro-inflammatory cytokines with chemokine-like functions that coordinate a wide spectrum of biological activities like migration. Here, we biotin-tagged intracellular MIF/D-DT in vivo to identify important cytosolic interactors and found a plethora of actin cytoskeleton-associated proteins. While the CD74/CD44 receptor complex is essential for signalling transduction in fibroblasts by extracellular MIF/D-DT, our interactome data rather suggested direct effects. We thus investigated whether MIF/D-DT can modulate cell migration independent of CD74/CD44. To differentiate between receptor- and non-receptor-mediated motility, we treated fibroblasts that are deficient in CD74 and CD44 or that express both proteins with recombinant MIF/D-DT. Interestingly, only MIF could stimulate chemokinesis in the presence or absence of CD74/CD44. The pro-migratory effects of MIF depended on lipid raft/caveolae-mediated but not clathrin-mediated endocytosis, on its tautomerase activity and, likely, on its thiol protein oxidoreductase activity. As MIF treatment restrained actin polymerisation in vitro our findings establish a new intracellular role for MIF/D-DT in driving cell motility by modulating the actin cytoskeleton.

Rheumatology Forecast: Why Prevention Matters.

Abstract: Recent epidemiologic surveys estimate an overall population prevalence of approximately 5% for autoimmune diseases, which comprise about 100 nosologically distinct entities (1). Many autoimmune diseases disproportionately affect women and occur more commonly or with greater severity in certain races or ethnicities. SLE, for instance is more common in those of African ancestry and in Asian populations. In our current issue, Dinse et al. report their analysis of the comparative prevalence of anti-nuclear antibody (ANA) in three US cohorts sampled over a 25 year period: 1988-91, 1999-04, and 2011-12 (2).

Macrophage Migration Inhibitory Factor is not Associated with Sarcoidosis Susceptibility or Severity in Whites or Blacks.

Abstract: Background Macrophage migration inhibitory factor (MIF) is an inflammatory cytokine, and increased MIF expression has been associated with the development and severity of multiple granulomatous, autoimmune diseases. However, MIF association studies have been discordant in sarcoidosis. Objective To evaluate associations between macrophage migration inhibitory factor (MIF) promoter polymorphisms and sarcoidosis susceptibility and severity. Methods Three hundred and fifty one patients with sarcoidosis were recruited through the Genomic Research in Alpha-1 Antitrypsin Deficiency and Sarcoidosis (GRADS) study. Genomic DNA was isolated from serum, and the MIF -173G/C SNP [rs755622] and MIF -794 CATT5-8 microsatellite repeat [rs5844572] were genotyped. Allelic frequencies were compared between cases and healthy controls and associations between MIF alleles and sarcoidosis severity were assessed. Results The frequencies of the high expression -173C SNP and the low expression -794 CATT5 containing genotypes in white and black sarcoidosis patients were the same as those of healthy controls. High expression MIF alleles were not associated with sarcoidosis severity. Associations between MIF alleles and extrapulmonary sarcoidosis phenotypes were limited by small sample sizes. Conclusions High expression MIF genotypes were not associated with the susceptibility to or severity of pulmonary sarcoidosis in a large North American cohort. (Sarcoidosis Vasc Diffuse Lung Dis 2020; 37 (3): e2020004).

Compounds and methods for treating copd and/or lung fibrosis

Abstract: In various aspects and embodiments the invention provides methods for the treatment of a MIF-mediated disease. In one aspect, the invention provides a method of treating a fibrotic disease in a male subject in need thereof, the method comprising administering to the male subject an effective amount of at least one MIF agonist. In various embodiments, the fibrotic disease is lung fibrosis. In another aspect, the invention provides a method of treating chronic obstructive pulmonary disease (COPD) in a female subject in need thereof, the method comprising administering to the female subject an effective amount of at least one MIF agonist. In various embodiments, the COPD is emphysema type COPD.