Design, Synthesis, and Biological Activity of New N-(Phenylmethyl)-benzoxazol-2-thiones as Macrophage Migration Inhibitory Factor (MIF) Antagonists: Efficacies in Experimental Pulmonary Hypertension

Novel insights and new therapeutic potentials for macrophages in pulmonary hypertension

Inflammation and immune processes underlie pulmonary hypertension progression. Two main different activated phenotypes of macrophages, classically activated M1 macrophages and alternatively activated M2 macrophages, are both involved in inflammatory processes related to pulmonary hypertension. Recent advances suggest that macrophages coordinate interactions among different proinflammatory and anti-inflammatory mediators, and other cellular components such as smooth muscle cells and fibroblasts. In this review, we summarize the current literature on the role of macrophages in the pathogenesis of pulmonary hypertension, including the origin of pulmonary macrophages and their response to triggers of pulmonary hypertension. We then discuss the interactions among macrophages, cytokines, and vascular adventitial fibroblasts in pulmonary hypertension, as well as the potential therapeutic benefits of macrophages in this disease. Identifying the critical role of macrophages in pulmonary hypertension will contribute to a comprehensive understanding of this pathophysiological abnormality, and may provide new perspectives for pulmonary hypertension management.

Downregulation of PDCD4 through STAT3/ATF6/autophagy mediates MIF-induced PASMCs proliferation/migration and vascular remodeling

To address the molecular mechanisms underlying macrophage migration inhibitory factor (MIF) induced pulmonary artery smooth muscle cells (PASMCs) proliferation, migration and vascular remodeling in pulmonary hypertension (PH), primary cultured rat PASMCs and monocrotaline (MCT)-induced rats with PH were applied in the present study. The results showed that MIF increased signal transducer and activator of transcription 3 (STAT3) phosphorylation, and then stimulated activating transcription factor 6 (ATF6) activation, subsequently triggered autophagy activation, which further led to programmed cell death factor 4 (PDCD4) lysosomal degradation, and eventually promoted PASMCs proliferation/migration. In lung tissues of MCT rats, MIF protein expression was elevated, phosphorylation of STAT3 and activation of ATF6 were increased, activation of autophagy was evident, and reduction of PDCD4 was observed. Intervention with MIF inhibitor 4-Iodo-6-phenylpyrimidine (4-IPP), ATF6 blocker melatonin or autophagy inhibitor chloroquine, confirmed the in vitro interaction among MIF, STAT3, ATF6, autophagy and PDCD4 in MCT induced rats with PH. Targeting MIF/STAT3/ATF6/autophagy/PDCD4 axis effectively prevented the development of PH by suppressing PASMCs proliferation and vascular remodeling. In conclusions, we demonstrate that MIF activates the STAT3/ATF6/autophagy cascade and then degrades PDCD4 leading to PASMCs proliferation/migration and pulmonary vascular remodeling, suggesting that intervention this axis might have potential value in management of PH.

Elevated plasma macrophage migration inhibitor factor is associated with hypertension and hypertensive left ventricular hypertrophy

Previous studies have found that the macrophage migration inhibitor factor is associated with endothelial dysfunction and ventricular remodelling. The aim of this study was to explore the potential relationship between plasma macrophage migration inhibitor factor levels and hypertension and hypertensive left ventricular hypertrophy. A total of 308 participants (including 187 uncomplicated hypertensive patients and 121 healthy controls) were enroled from 2017 to 2019. The association between macrophage migration inhibitor factors and hypertension and hypertensive left ventricular hypertrophy was estimated with univariate and multivariate logistic regression models. Elevated macrophage migration inhibitor factor was associated with the development of hypertension (second tertile: adjusted OR, 2.27, 95% CI, 1.24-4.16, P = 0.008; third tertile: adjusted OR, 5.43, 95% CI, 2.75-10.71, P < 0.001; compared with the first tertile). In addition, we assessed the association between macrophage migration inhibitor factor and left ventricular hypertrophy in hypertensive patients (n = 187). Plasma macrophage migration inhibitor factor was significantly correlated with hypertensive left ventricular mass index (r = 0.580, P < 0.001). In patients with hypertension, an elevated macrophage migration inhibitor factor was significantly associated with hypertensive left ventricular hypertrophy (second tertile: adjusted OR, 3.20, 95% CI, 1.17-8.78, P = 0.024; third tertile: adjusted OR, 24.95, 95% CI, 8.72-71.41, P < 0.001; compared with the first tertile). Receiver operating characteristic analysis indicated that macrophage migration inhibitor factor had reasonable predictive accuracy for the development of hypertensive left ventricular hypertrophy (area under curve 0.84, 95% CI 0.78-0.90, P < 0.001). Our data indicated that elevated macrophage migration inhibitor factor is associated with hypertension and hypertensive left ventricular hypertrophy.

Cathode enabled high faradaic efficiency: reduction of imines to amines with H2O as a H-source

Benefiting from a high overpotential of the competitive hydrogen evolution reaction with a carbon paper cathode, the desired electrochemical reduction of imines was achieved with high faradaic efficiency by using H₂O as a H-source. With this sustainable atom-economic strategy, a series of potentially versatile amines were obtained in medium-to-high yields (49-86%).

Molecular modeling in cardiovascular pharmacology: Current state of the art and perspectives

Molecular modeling in pharmacology is a promising emerging tool for exploring drug interactions with cellular components. Recent advances in molecular simulations, big data analysis, and artificial intelligence (AI) have opened new opportunities for rationalizing drug interactions with their pharmacological targets. Despite the obvious utility and increasing impact of computational approaches, their development is not progressing at the same speed in different fields of pharmacology. Here, we review current in silico techniques used in cardiovascular diseases (CVDs), cardiological drug discovery, and assessment of cardiotoxicity. In silico techniques are paving the way to a new era in cardiovascular medicine, but their use somewhat lags behind that in other fields.

Impact of Parthanatos on the Increased Risk of Onset and Mortality in Male Patients With Pulmonary Hypertension

There have been no studies as to whether parthanatos, a poly (adenosine diphosphate-ribose) polymerase-1 (PARP-1)-dependent and apoptosis-inducing factor (AIF)-mediated caspase-independent programmed cell death, is present in pulmonary hypertension (PH). Basic studies have, however, been conducted on several of the key molecules in parthanatos, such as PARP-1, AIF, and macrophage migration inhibitory factor (MIF). For this study, we collected blood samples from 88 incident male patients with PH and 50 healthy controls at the Shanghai Pulmonary Hospital. We measured the key factors of parthanatos (PARP-1, PAR, AIF, and MIF) by enzyme-linked immunosorbent assay and performed a logistic regression, Cox proportional hazards analysis, and Kaplan-Meier test to assess the prognostic value of the key molecules in diagnosing and predicting survival. The patients who ultimately died had a significantly poorer clinical status during the study than those who survived. The PARP-1, PAR, AIF, and MIF levels were significantly higher in the patients than in the controls (all p < .0001), and the PARP-1, PAR, and AIF levels were higher in the nonsurvivors than in the survivors (all p < .0001). PARP-1 and AIF levels served as independent predictors of disease onset and mortality in these patients (all p < .005). Patients with PARP-1 levels <11.24 ng/mL or AIF levels <1.459 pg/mL had significantly better survival than those with higher PARP-1 or AIF levels (p < .0001). Circulating levels of PARP-1 and AIF were independent predictors for PH onset and mortality, which indicated that parthanatos might be associated with the pathogenesis of PH.

Visible light-driven oxidative coupling of dibenzylamine and substituted anilines with a 2D WSe2 nanomesh material

A novel 2D WSe2 nanomesh material was synthesized with a 3D SBA-15 mesoporous material via a nanocasting strategy. The formation of the 2D sheet-like nanomesh structure of WSe2 inside a 3D confined pore space is mainly attributed to the synergistic effect arising from the crystal self-limitation growth caused by the layered crystal structure of the WSe2 material and to the space-limitation effect coming from the unique pore structure of the SBA-15 template. The 2D WSe2 nanomesh material possesses extremely high exposure of crystal layer edges, making it an excellent photocatalyst. It shows good visible light-driven photocatalytic performance in oxidative coupling of dibenzylamine and 2-amino/hydroxy/mercaptoanilines to prepare a group of heterocyclic compounds, including benzimidazoles, benzoxazoles and benzothiazoles with oxygen as the sole oxidant. A gram-scale experiment was also carried out to exhibit the scope of this method.

Neutralization of CXCL12 attenuates established pulmonary hypertension in rats

AIMS

The progressive accumulation of cells in pulmonary vascular walls is a key pathological feature of pulmonary arterial hypertension (PAH) that results in narrowing of the vessel lumen, but treatments targeting this mechanism are lacking. The C-X-C motif chemokine 12 (CXCL12) appears to be crucial in these processes. We investigated the activity of two CXCL12 neutraligands on experimental pulmonary hypertension (PH), using two complementary animal models.

METHODS AND RESULTS

Male Wistar rats were injected with monocrotaline (MCT) or were subjected to SU5416 followed by 3-week hypoxia to induce severe PH. After PH establishment, assessed by pulsed-wave Doppler echocardiography, MCT-injected or SU5416 plus chronic hypoxia (SuHx) rats were randomized to receive CXCL12 neutraligands chalcone 4 or LIT-927 (100 mg/kg/day), the C-X-C motif chemokine receptor 4 (CXCR4) antagonist AMD3100 (5 mg/kg/day), or vehicle, for 2 or 3 weeks, respectively. At the end of these treatment periods, echocardiographic and haemodynamic measurements were performed and tissue samples were collected for protein expression and histological analysis. Daily treatment of MCT-injected or SuHx rats with established PH with chalcone 4 or LIT-927 partially reversed established PH, reducing total pulmonary vascular resistance, and remodelling of pulmonary arterioles. Consistent with these observations, we found that neutralization of CXCL12 attenuates right ventricular hypertrophy, pulmonary vascular remodelling, and decreases pulmonary artery smooth muscle cell (PA-SMC) proliferation in lungs of MCT-injected rats and SuHx rats. Importantly, CXCL12 neutralization with either chalcone 4 or LIT-927 inhibited the migration of PA-SMCs and pericytes in vitro with a better efficacy than AMD3100. Finally, we found that CXCL12 neutralization decreases vascular pericyte coverage and macrophage infiltration in lungs of both MCT-injected and SuHx rats.

CONCLUSION

We report here a greater beneficial effect of CXCL12 neutralization vs. the conventional CXCR4 blockade with AMD3100 in the MCT and SuHx rat models of severe PH, supporting a role for CXCL12 in the progression of vascular complications in PH and opening to new therapeutic options.

Multiple roles of macrophage migration inhibitory factor in pulmonary hypertension

Pulmonary hypertension (PH) is a life-threatening condition arising from the loss and obstructive remodeling of the pulmonary arteries, leading to the sustained elevation of pulmonary arterial pressure (PAP) and pulmonary vascular resistance (PVR) and subsequently right ventricular (RV) failure and death. PH encompasses a group of multifactorial diseases, such as pulmonary arterial hypertension (PAH) and chronic thromboembolic PH, for which there is no treatment that can stop or reverse the progression of remodeling of the pulmonary vasculature. The identification of new molecular targets for the development of more effective drugs is thus urgently needed. In this context, macrophage migration inhibitory factor (MIF), a pleiotropic upstream proinflammatory mediator, is emerging as a promising molecular target, as it contributes to perivascular inflammation and pulmonary arterial remodeling, two key hallmarks of PAH that are not specifically targeted by currently approved therapies. The objective of this review is to summarize the scientific evidence on the pathogenic roles of MIF and its potential as a biomarker and therapeutic target in PH/PAH.

Key inflammatory pathways underlying vascular remodeling in pulmonary hypertension

Independent of the underlying cause, pulmonary hypertension (PH) remains a devastating condition that is characterized by limited survival. Cumulating evidence indicates that in addition to a dysbalance of mediators regulating vascular tone and growth factors promoting vascular remodeling, failure to resolve inflammation and altered immune processes play a pivotal role in the development and progression of PH. Here, we highlight the role of key inflammatory pathways in the pathobiology of vascular remodeling and PH, and discuss potential therapeutic interventions that may halt disease progression or even reverse pulmonary vascular remodeling. Perivascular inflammation is present in all forms of PH, and inflammatory pathways involve numerous mediators and cell types including macrophages, neutrophils, T cells, dendritic cells, and mast cells. Dysfunctional bone morphogenic protein receptor 2 (BMPR2) signaling and dysregulated immunity enable the accumulation of macrophages and other inflammatory cells in obliterative vascular lesions. Regulatory T cells (Tregs) were shown to be of particular relevance in the control of inflammatory responses. Key cytokines/chemokines include interleukin-6, functioning via classic or trans-signaling, macrophage migratory inhibitory factor (MIF), but also other mediators such as neutrophil-derived myeloperoxidase. The expanding knowledge on this topic has resulted in multiple opportunities for sophisticated therapeutic interventions.

[New insights in the pathogenesis of pulmonary arterial hypertension]

Pulmonary arterial hypertension (PAH) is a severe and incurable cardiopulmonary disorder. Research from the past 10 years illustrates the complex and multifactorial aspects of PAH pathophysiology. Furthermore, latest advances in the field have led to a better understanding of the key components underlying this inadequate accumulation of pulmonary vascular cells within the pulmonary arterial walls, leading to pulmonary vascular remodelling. Among the underlying molecular and cellular mechanisms, pulmonary endothelial dysfunction, alterations of the inter-cell communications within the pulmonary arterial walls as well as defects of the inflammatory component and the loss of BMPRII activity play critical roles in the pathogenesis of the disease.

Models for Cooperative Catalysis: Oxidative Addition Reactions of Dimethylplatinum(II) Complexes with Ligands Having Both NH and OH Functionality

The role of NH and OH groups in the oxidative addition reactions of the complexes [PtMe₂(κ²-N,N'-L)], L = 2-C₅H₄NCH₂NH-x-C₆H₄OH [3, x = 2, L = L1; 4, x = 3, L = L2; 5, x = 4, L = L3], has been investigated. Complex 3 is the most reactive. It reacts with CH₂Cl₂ to give a mixture of isomers of [PtMe₂(CH₂Cl)(κ³-N,N',O-(L1-H)], 6, and decomposes in acetone to give [PtMe₃(κ³-N,N',O-(L1-H)], 7, both of which contain the fac tridentate deprotonated ligand. Complex 3 reacts with MeI to give complex 7, whereas 4 and 5 react to give [PtIMe₃(κ²-N,N'-L2))], 8, or [PtIMe₃(κ²-N,N'-L3)], 9, respectively. Each complex 3, 4, or 5 reacts with either dioxygen or hydrogen peroxide to give the corresponding complex [Pt(OH)₂Me₂(κ²-N,N'-L)], 10, L = L1; 11, L = L2; 12, L = L3. The ligand L3 in complexes 9 and 12 is easily oxidized to the corresponding imine ligand 2-C₅H₄NCH=N-4-C₆H₄OH, L4, in forming the complexes [PtIMe₃(κ²-N,N'-L4)], 13, and [Pt(OH)₂Me₂(κ²-N,N'-L4)], 14, respectively. The NH and OH groups play a significant role in supramolecular polymer or sheet structures of the complexes, formed through intermolecular hydrogen bonding, and these structures indicate how either intramolecular or intermolecular hydrogen bonding may assist some oxidative addition reactions.

Macrophage Migration Inhibitory Factor (MIF) Inhibition in a Murine Model of Bleomycin-Induced Pulmonary Fibrosis

Background: Pulmonary hypertension (PH) is a common complication of idiopathic pulmonary fibrosis (IPF) that significantly contributes to morbidity and mortality. Macrophage migration inhibitory factor (MIF) is a critical factor in vascular remodeling of the pulmonary circulation. Objectives: We tested the effects of two small molecules targeting MIF on bleomycin (BLM)-induced collagen deposition, PH, and vascular remodeling in mouse lungs. Methods: We examined the distribution pattern of MIF, CD74, and CXCR4 in the lungs of patients with IPF-PH and the lungs of BLM-injected mice. Then, treatments were realized with (S,R)-3-(4-hydroxyphenyl)-4,5-dihydro-5-isoxazole acetic acid methyl ester (ISO-1) and N-(3-hydroxy-4-fluorobenzyl)-5 trifluoromethylbenzoxazol-2-thione 31 (20 mg/kg/day per os for 3 weeks) started 24 h after an intratracheal BLM administration. Results: More intense immunoreactivity was noted for MIF, CD74, and CXCR4 in lungs from IPF-PH patients and BLM-injected mice. Furthermore, we found that treatments of BLM-injected mice with ISO-1 or compound 31 attenuated lung collagen deposition and right ventricular systolic pressure increase. Additionally, reduced pulmonary inflammatory infiltration and pulmonary arterial muscularization were observed in the lungs of BLM-injected mice treated with ISO-1 or compound 31. Conclusions: Treatments with ISO-1 or compound 31 attenuates BLM-induced inflammation and fibrosis in lung, and prevents PH development in mice, suggesting that MIF is an important factor for IPF-PH development.

Role of MIF and D-DT in immune-inflammatory, autoimmune, and chronic respiratory diseases: from pathogenic factors to therapeutic targets

Macrophage migration inhibitory factor (MIF) is a protein that acts as a cytokine-, enzyme-, endocrine- and chaperon-like molecule. It binds to the cell-surface receptor CD74 in association with CD44, which activates the downstream signal transduction pathway. In addition, MIF acts also as a noncognate ligand for C-X-C chemokine receptor type 2 (CXCR2), type 4 (CXCR4), and type 7 (CXCR7). Recently, D-dopachrome tautomerase (D-DT), a second member of the MIF superfamily, was identified. From a pharmacological and clinical point of view, the nonredundant biological properties of MIF and D-DT anticipate potential synergisms from their simultaneous inhibition. Here, we focus on the role of MIF and D-DT in human immune-inflammatory, autoimmune, and chronic respiratory diseases, providing an update on the progress made in the identification of specific small-molecule inhibitors of these proteins.

Advances and Insights for Small Molecule Inhibition of Macrophage Migration Inhibitory Factor

Macrophage migration inhibitory factor (MIF) is an upstream regulator of the immune response whose dysregulation is tied to a broad spectrum of inflammatory and proliferative disorders. As its complex signaling pathways and pleiotropic nature have been elucidated, it has become an attractive target for drug discovery. Remarkably, MIF is both a cytokine and an enzyme that functions as a keto-enol tautomerase. Strategies including in silico modeling, virtual screening, high-throughput screening, and screening of anti-inflammatory natural products have led to a large and diverse catalogue of MIF inhibitors as well as some understanding of the structure-activity relationships for compounds binding MIF's tautomerase active site. With possible clinical trials of some MIF inhibitors on the horizon, it is an opportune time to review the literature to seek trends, address inconsistencies, and identify promising new avenues of research.

Predictive potential of macrophage migration inhibitory factor (MIF) in patients with heart failure with preserved ejection fraction (HFpEF)

Background

Prognostication in heart failure with preserved ejection fraction (HFpEF) is challenging and novel biomarkers are urgently needed. Macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine that plays a crucial role in cardiovascular and various inflammatory diseases. Whether MIF is involved in HFpEF is unknown.

Methods and results

Sixty-two patients with HFpEF were enrolled and followed up for 180 days. MIF plasma levels as well as natriuretic peptide (NP) levels were assessed. High MIF levels significantly predicted the combined end-point of all-cause death or hospitalization at 180 days in the univariate analysis (HR 2.41, 95% CI 1.12–5.19, p = 0.025) and after adjustment for relevant covariates in a Cox proportional hazard regression model (HR 2.35, 95% CI 1.05–5.27, p = 0.0374). Furthermore, MIF levels above the median were associated with higher pulmonary artery systolic pressure (PASP) as assessed by echocardiography (PASP 31 mmHg vs 48 mmHg in the low- and high-MIF group, respectively, p = 0.017). NPs significantly correlated with MIF in HFpEF patients (BNP p = 0.011; r = 0.32; NT-proBNP p = 0.027; r = 0.28).

Conclusion

MIF was associated with clinical outcomes and might be involved in the pathophysiology of pulmonary hypertension in patients with HFpEF. These first data on MIF in HFpEF should stimulate further research to elucidate the role of this cytokine in heart failure.

Trial registration NCT03232671