Blocking the Self-Destruct Program of Dopamine Neurons through Macrophage Migration Inhibitory Factor Nuclease Inhibition

Parkinson's disease (PD) is a progressive neurodegenerative condition that pathognomonically involves the death of dopaminergic neurons in the substantia nigra pars compacta, resulting in a myriad of motor and non-motor symptoms. Given the insurmountable burden of this disease on the population and healthcare system, significant efforts have been put forth toward generating disease modifying therapies. This class of treatments characteristically alters disease course, as opposed to current strategies that focus on managing symptoms. Previous literature has implicated the cell death pathway known as parthanatos in PD progression. Inhibition of this pathway by targeting poly (ADP)-ribose polymerase 1 (PARP1) prevents neurodegeneration in a model of idiopathic PD. However, PARP1 has a vast repertoire of functions within the body, increasing the probability of side effects with the long-term treatment likely necessary for clinically significant neuroprotection. Recent work culminated in the development of a novel agent targeting the macrophage migration inhibitory factor (MIF) nuclease domain, also named parthanatos-associated apoptosis-inducing factor nuclease (PAAN). This nuclease activity specifically executes the terminal step in parthanatos. Parthanatos-associated apoptosis-inducing factor nuclease inhibitor-1 was neuroprotective in multiple preclinical mouse models of PD. This piece will focus on contextualizing this discovery, emphasizing its significance, and discussing its potential implications for parthanatos-directed treatment. © 2024 International Parkinson and Movement Disorder Society.

Murine double minute 2-mediated estrogen receptor 1 degradation activates macrophage migration inhibitory factor to promote vascular smooth muscle cell dedifferentiation and oxidative stress during thoracic aortic aneurysm progression

Estrogen receptor 1 (ESR1) has been recently demonstrated as a potential diagnostic biomarker for thoracic aortic aneurysm (TAA). However, its precise role in the progression of TAA remains unclear. In this study, TAA models were established in ApoE-knockout mice and primary mouse vascular smooth muscle cells (VSMCs) through treatment with angiotensin (Ang) II. Our findings revealed a downregulation of ESR1 in Ang II-induced TAA mice and VSMCs. Upregulation of ESR1 mitigated expansion and cell apoptosis in the mouse aorta, reduced pathogenetic transformation of VSMCs, and reduced inflammatory infiltration and oxidative stress both in vitro and in vivo. Furthermore, we identified macrophage migration inhibitory factor (MIF) as a biological target of ESR1. ESR1 bound to the MIF promoter to suppress its transcription. Artificial MIF restoration negated the mitigating effects of ESR1 on TAA. Additionally, we discovered that murine double minute 2 (MDM2) was highly expressed in TAA models and mediated protein degradation of ESR1 through ubiquitination modification. Silencing of MDM2 reduced VSMC dedifferentiation and suppressed oxidative stress. However, these effects were reversed upon further silencing of ESR1. In conclusion, this study demonstrates that MDM2 activates MIF by mediating ESR1 degradation, thus promoting VSMC dedifferentiation and oxidative stress during TAA progression.

Top Five Stories of the Cellular Landscape and Therapies of Atherosclerosis: Current Knowledge and Future Perspectives

Atherosclerosis (AS) is characterized by impairment and apoptosis of endothelial cells, continuous systemic and focal inflammation and dysfunction of vascular smooth muscle cells, which is documented as the traditional cellular paradigm. However, the mechanisms appear much more complicated than we thought since a bulk of studies on efferocytosis, transdifferentiation and novel cell death forms such as ferroptosis, pyroptosis, and extracellular trap were reported. Discovery of novel pathological cellular landscapes provides a large number of therapeutic targets. On the other side, the unsatisfactory therapeutic effects of current treatment with lipid-lowering drugs as the cornerstone also restricts the efforts to reduce global AS burden. Stem cell- or nanoparticle-based strategies spurred a lot of attention due to the attractive therapeutic effects and minimized adverse effects. Given the complexity of pathological changes of AS, attempts to develop an almighty medicine based on single mechanisms could be theoretically challenging. In this review, the top stories in the cellular landscapes during the initiation and progression of AS and the therapies were summarized in an integrated perspective to facilitate efforts to develop a multi-targets strategy and fill the gap between mechanism research and clinical translation. The future challenges and improvements were also discussed.

DDX5 inhibits inflammation by modulating m6A levels of TLR2/4 transcripts during bacterial infection

DExD/H-box helicases are crucial regulators of RNA metabolism and antiviral innate immune responses; however, their role in bacteria-induced inflammation remains unclear. Here, we report that DDX5 interacts with METTL3 and METTL14 to form an m6A writing complex, which adds N6-methyladenosine to transcripts of toll-like receptor (TLR) 2 and TLR4, promoting their decay via YTHDF2-mediated RNA degradation, resulting in reduced expression of TLR2/4. Upon bacterial infection, DDX5 is recruited to Hrd1 at the endoplasmic reticulum in an MyD88-dependent manner and is degraded by the ubiquitin-proteasome pathway. This process disrupts the DDX5 m6A writing complex and halts m6A modification as well as degradation of TLR2/4 mRNAs, thereby promoting the expression of TLR2 and TLR4 and downstream NF-κB activation. The role of DDX5 in regulating inflammation is also validated in vivo, as DDX5- and METTL3-KO mice exhibit enhanced expression of inflammatory cytokines. Our findings show that DDX5 acts as a molecular switch to regulate inflammation during bacterial infection and shed light on mechanisms of quiescent inflammation during homeostasis.

Myeloid-derived growth factor suppresses VSMC dedifferentiation and attenuates postinjury neointimal formation in rats by activating S1PR2 and its downstream signaling

Restenosis after angioplasty is caused usually by neointima formation characterized by aberrant vascular smooth muscle cell (VSMC) dedifferentiation. Myeloid-derived growth factor (MYDGF), secreted from bone marrow-derived monocytes and macrophages, has been found to have cardioprotective effects. In this study we investigated the effect of MYDGF to postinjury neointimal formation and the underlying mechanisms. Rat carotid arteries balloon-injured model was established. We found that plasma MYDGF content and the level of MYDGF in injured arteries were significantly decreased after balloon injury. Local application of exogenous MYDGF (50 μg/mL) around the injured vessel during balloon injury markedly ameliorated the development of neointimal formation evidenced by relieving the narrow endovascular diameter, improving hemodynamics, and reducing collagen deposition. In addition, local application of MYDGF inhibited VSMC dedifferentiation, which was proved by reversing the elevated levels of osteopontin (OPN) protein and decreased levels of α-smooth muscle actin (α-SMA) in the left carotid arteries. We showed that PDGF-BB (30 ng/mL) stimulated VSMC proliferation, migration and dedifferentiation in vitro; pretreatment with MYDGF (50-200 ng/mL) concentration-dependently eliminated PDGF-BB-induced cell proliferation, migration and dedifferentiation. Molecular docking revealed that MYDGF had the potential to bind with sphingosine-1-phosphate receptor 2 (S1PR2), which was confirmed by SPR assay and Co-IP analysis. Pretreatment with CCG-1423 (Rho signaling inhibitor), JTE-013 (S1PR2 antagonist) or Ripasudil (ROCK inhibitor) circumvented the inhibitory effects of MYDGF on VSMC phenotypic switching through inhibiting S1PR2 or its downstream RhoA-actin monomers (G-actin) /actin filaments (F-actin)-MRTF-A signaling. In summary, this study proves that MYDGF relieves neointimal formation of carotid arteries in response to balloon injury in rats, and suppresses VSMC dedifferentiation induced by PDGF-BB via S1PR2-RhoA-G/F-actin-MRTF-A signaling pathway. In addition, our results provide evidence for cross talk between bone marrow and vasculature.

Superfamily II helicases: the potential therapeutic target for cardiovascular diseases

Cardiovascular diseases (CVDs) still maintain high morbidity and mortality globally. Helicases, a unique class of enzymes, are extensively implicated in the processes of nucleic acid (NA) metabolism across various organisms. They play a pivotal role in gene expression, inflammatory response, lipid metabolism, and so forth. However, abnormal helicase expression has been associated with immune response, cancer, and intellectual disability in humans. Superfamily II (SFII) is one of the largest and most diverse of the helicase superfamilies. Increasing evidence has implicated SFⅡ helicases in the pathogenesis of multiple CVDs. In this review, we comprehensively review the regulation mechanism of SFⅡ helicases in CVDs including atherosclerosis, myocardial infarction, cardiomyopathies, and heart failure, which will contribute to the investigation of ideal therapeutic targets for CVDs.

Hypoxia and panvascular diseases: exploring the role of hypoxia-inducible factors in vascular smooth muscle cells under panvascular pathologies

As an emerging discipline, panvascular diseases are a set of vascular diseases with atherosclerosis as the common pathogenic hallmark, which mostly affect vital organs like the heart, brain, kidney, and limbs. As the major responser to the most common stressor in the vasculature (hypoxia)-hypoxia-inducible factors (HIFs), and the primary regulator of pressure and oxygen delivery in the vasculature-vascular smooth muscle cells (VSMCs), their own multifaceted nature and their interactions with each other are fascinating. Abnormally active VSMCs (e.g., atherosclerosis, pulmonary hypertension) or abnormally dysfunctional VSMCs (e.g., aneurysms, vascular calcification) are associated with HIFs. These widespread systemic diseases also reflect the interdisciplinary nature of panvascular medicine. Moreover, given the comparable proliferative characteristics exhibited by VSMCs and cancer cells, and the delicate equilibrium between angiogenesis and cancer progression, there is a pressing need for more accurate modulation targets or combination approaches to bolster the effectiveness of HIF targeting therapies. Based on the aforementioned content, this review primarily focused on the significance of integrating the overall and local perspectives, as well as temporal and spatial balance, in the context of the HIF signaling pathway in VSMC-related panvascular diseases. Furthermore, the review discussed the implications of HIF-targeting drugs on panvascular disorders, while considering the trade-offs involved.

Dualistic roles and mechanistic insights of macrophage migration inhibitory factor in brain injury and neurodegenerative diseases

Macrophage migration inhibitory factor (MIF) is involved in various immune-mediated pathologies and regulates both innate and adaptive immune reactions, thus being related to several acute and chronic inflammatory diseases such as rheumatoid arthritis, septic shock, and atherosclerosis. Its role in acute and chronic brain pathologies, such as stroke and neurodegenerative diseases, has attracted increasing attention in recent years. In response to stimuli like hypoxia, inflammation or infection, different cell types can rapidly release MIF, including immune cells, endothelial cells, and neuron cells. Notably, clinical data from past decades also suggested a possible link between serum MIF levels and the severity of stroke and the evolving of neurodegenerative diseases. In this review, we summarize the major and recent findings focusing on the mechanisms of MIF modulating functions in brain injury and neurodegenerative diseases, which may provide important therapeutic targets meriting further investigation.

Pathways linking aging and atheroprotection in Mif-deficient atherosclerotic mice

Atherosclerosis is a chronic inflammatory condition of our arteries and the main underlying pathology of myocardial infarction and stroke. The pathogenesis is age-dependent, but the links between disease progression, age, and atherogenic cytokines and chemokines are incompletely understood. Here, we studied the chemokine-like inflammatory cytokine macrophage migration inhibitory factor (MIF) in atherogenic Apoe^-/- mice across different stages of aging and cholesterol-rich high-fat diet (HFD). MIF promotes atherosclerosis by mediating leukocyte recruitment, lesional inflammation, and suppressing atheroprotective B cells. However, links between MIF and advanced atherosclerosis across aging have not been systematically explored. We compared effects of global Mif-gene deficiency in 30-, 42-, and 48-week-old Apoe^-/- mice on HFD for 24, 36, or 42 weeks, respectively, and in 52-week-old mice on a 6-week HFD. Mif-deficient mice exhibited reduced atherosclerotic lesions in the 30/24- and 42/36-week-old groups, but atheroprotection, which in the applied Apoe^-/- model was limited to lesions in the brachiocephalic artery and abdominal aorta, was not detected in the 48/42- and 52/6-week-old groups. This suggested that atheroprotection afforded by global Mif-gene deletion differs across aging stages and atherogenic diet duration. To characterize this phenotype and study the underlying mechanisms, we determined immune cells in the periphery and vascular lesions, obtained a multiplex cytokine/chemokine profile, and compared the transcriptome between the age-related phenotypes. We found that Mif deficiency promotes lesional macrophage and T-cell counts in younger but not aged mice, with subgroup analysis pointing toward a role for Trem2⁺ macrophages. The transcriptomic analysis identified pronounced MIF- and aging-dependent changes in pathways predominantly related to lipid synthesis and metabolism, lipid storage, and brown fat cell differentiation, as well as immunity, and atherosclerosis-relevant enriched genes such as Plin1, Ldlr, Cpne7, or Il34, hinting toward effects on lesional lipids, foamy macrophages, and immune cells. Moreover, Mif-deficient aged mice exhibited a distinct plasma cytokine/chemokine signature consistent with the notion that mediators known to drive inflamm'aging are either not downregulated or even upregulated in Mif-deficient aged mice compared with the corresponding younger ones. Lastly, Mif deficiency favored formation of lymphocyte-rich peri-adventitial leukocyte clusters. While the causative contributions of these mechanistic pillars and their interplay will be subject to future scrutiny, our study suggests that atheroprotection due to global Mif-gene deficiency in atherogenic Apoe^-/- mice is reduced upon advanced aging and identifies previously unrecognized cellular and molecular targets that could explain this phenotype shift. These observations enhance our understanding of inflamm'aging and MIF pathways in atherosclerosis and may have implications for translational MIF-directed strategies.

Effect of macrophage migration inhibitory factor on pulmonary vein arrhythmogenesis through late sodium current

AIMS

Macrophage migration inhibitory factor (MIF), a pleiotropic inflammatory cytokine, is highly expressed in patients with atrial fibrillation (AF). Inflammation increases the risk of AF and is primarily triggered by pulmonary vein (PV) arrhythmogenesis. This study investigated whether MIF can modulate the electrical activity of the PV and examined the underlying mechanisms of MIF.

METHODS AND RESULTS

A conventional microelectrode, a whole-cell patch clamp, western blotting, and immunofluorescent confocal microscopy were used to investigate electrical activity, calcium (Ca2+) regulation, protein expression, ionic currents, and cytosolic reactive oxygen species (ROS) in rabbit PV tissue and isolated single cardiomyocytes with and without MIF incubation (100 ng/mL, treated for 6 h). The MIF (100 ng/mL)-treated PV tissue (n = 8) demonstrated a faster beating rate (1.8 ± 0.2 vs. 2.6 ± 0.1 Hz, P < 0.05), higher incidence of triggered activity (12.5 vs. 100%, P < 0.05), and premature atrial beat (0 vs. 100%, P < 0.05) than the control PV tissue (n = 8). Compared with the control PV cardiomyocytes, MIF-treated single PV cardiomyocytes had larger Ca2+ transients (0.6 ± 0.1 vs. 1.0 ± 0.1, ΔF/F0, P < 0.05), sarcoplasmic reticulum Ca2+ content (0.9 ± 0.20 vs. 1.7 ± 0.3 mM of cytosol, P < 0.05), and cytosolic ROS (146.8 ± 5.3 vs. 163.7 ± 3.8, ΔF/F0, P < 0.05). Moreover, MIF-treated PV cardiomyocytes exhibited larger late sodium currents (INa-Late), L-type Ca2+ currents, and Na+/Ca2+ exchanger currents than the control PV cardiomyocytes. KN93 [a selective calcium/calmodulin-dependent protein kinase II (CaMKII) blocker, 1 μM], ranolazine (an INa-Late inhibitor, 10 μM), and N-(mercaptopropionyl) glycine (ROS inhibitor, 10 mM) reduced the beating rates and the incidence of triggered activity and premature captures in the MIF-treated PV tissue.

CONCLUSION

Macrophage migration inhibitory factor increased PV arrhythmogenesis through Na+ and Ca2+ dysregulation through the ROS activation of CaMKII signalling, which may contribute to the genesis of AF during inflammation. Anti-CaMKII treatment may reverse PV arrhythmogenesis. Our results clearly reveal a key link between MIF and AF and offer a viable therapeutic target for AF treatment.

An update on the phenotypic switching of vascular smooth muscle cells in the pathogenesis of atherosclerosis

Vascular smooth muscle cells (VSMCs) are involved in phenotypic switching in atherosclerosis. This switching is characterized by VSMC dedifferentiation, migration, and transdifferentiation into other cell types. VSMC phenotypic transitions have historically been considered bidirectional processes. Cells can adopt a physiological contraction phenotype or an alternative "synthetic" phenotype in response to injury. However, recent studies, including lineage tracing and single-cell sequencing studies, have shown that VSMCs downregulate contraction markers during atherosclerosis while adopting other phenotypes, including macrophage-like, foam cell, mesenchymal stem-like, myofibroblast-like, and osteochondral-like phenotypes. However, the molecular mechanism and processes regulating the switching of VSMCs at the onset of atherosclerosis are still unclear. This systematic review aims to review the critical outstanding challenges and issues that need further investigation and summarize the current knowledge in this field.

Macrophage migration inhibitory factor (MIF): A multifaceted cytokine regulated by genetic and physiological strategies

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine encoded within a functionally polymorphic genetic locus. MIF was initially recognized as a cytokine generated by activated T cells, but in recent days it has been identified as a multipotent key cytokine secreted by many other cell types involved in immune response and physiological processes. MIF is a highly conserved 12.5 kDa secretory protein that is involved in numerous biological processes. The expression and secretion profile of MIF suggests that MIF to be ubiquitously and constitutively expressed in almost all mammalian cells and is vital for numerous physiological processes. MIF is a critical upstream mediator of host innate and adaptive immunity and survival pathways resulting in the clearance of pathogens thus playing a protective role during infectious diseases. On the other hand, MIF being an immune modulator accelerates detrimental inflammation, promotes cancer metastasis and progression, thus worsening disease conditions. Several reports demonstrated that genetic and physiological factors, including MIF gene polymorphisms, posttranslational regulations, and receptor binding control the functional activities of MIF. Taking into consideration the multi-faceted role of MIF both in physiology and pathology, we thought it is timely to review and summarize the expressional and functional regulation of MIF, its functional mechanisms associated with its beneficial and pathological roles, and MIF-targeting therapies. Thus, our review will provide an overview on how MIF is regulated, its response, and the potency of the therapies that target MIF.

The RNA helicase DDX5 promotes viral infection via regulating N6-methyladenosine levels on the DHX58 and NFκB transcripts to dampen antiviral innate immunity

Multi-functional DEAD-box helicase 5 (DDX5), which is important in transcriptional regulation, is hijacked by diverse viruses to facilitate viral replication. However, its regulatory effect in antiviral innate immunity remains unclear. We found that DDX5 interacts with the N⁶-methyladenosine (m6A) writer METTL3 to regulate methylation of mRNA through affecting the m6A writer METTL3–METTL14 heterodimer complex. Meanwhile, DDX5 promoted the m6A modification and nuclear export of transcripts DHX58, p65, and IKKγ by binding conserved UGCUGCAG element in innate response after viral infection. Stable IKKγ and p65 transcripts underwent YTHDF2-dependent mRNA decay, whereas DHX58 translation was promoted, resulting in inhibited antiviral innate response by DDX5 via blocking the p65 pathway and activating the DHX58-TBK1 pathway after infection with RNA virus. Furthermore, we found that DDX5 suppresses antiviral innate immunity in vivo. Our findings reveal that DDX5 serves as a negative regulator of innate immunity by promoting RNA methylation of antiviral transcripts and consequently facilitating viral propagation.

DEAD-box helicase 5 (DDX5) greatly contributes to cancer development and facilitation of viral propagation. However, how DDX5 manipulates host cell processes to facilitate replication remains poorly understood. In this study, we found DDX5 is a negative antiviral regulator through manipulating N⁶-methyladenosine (m6A) of transcripts in innate immunity. Firstly, DDX5 recruited the RNA m6A “writer” METTL3 to control the m6A writer complex, then specifically promoted m6A modification and nuclear export of DDX5 binding transcripts by binding conserved UGCUGCAG element in innate immune response, ultimately, leading to RNA decay of antiviral transcripts in a YTHDF2-dependent manner. Consequently, DDX5 played vital roles in cellular RNA metabolisms to negatively regulate innate immune response to viral infection. It is the first time to unravel DDX5 as an important component that mediates modification of N⁶-methyladenosine of mRNA in regulating innate immunity.

TWIST1 induces phenotypic switching of vascular smooth muscle cells by downregulating p68 and microRNA-143/145

TWIST1 is an important basic helix‐loop‐helix protein linked to multiple physiological and pathological processes. Although TWIST1 is believed to be involved in vascular pathogenesis, its effects on homeostasis of smooth muscle cells (SMCs) remain poorly understood. Here, we show that TWIST1 protein levels were significantly elevated during SMC phenotypic switching in vivo and in vitro. TWIST1 overexpression promoted phenotypic switching of SMCs, while siRNA targeting of TWIST1 prevented cell transition. Mechanistically, TWIST1 decreased the level of microRNA‐143/145, which governs smooth muscle marker gene transcription. In addition, TWIST1 repressed p68 mRNA and protein expression, a crucial modulator of SMC behavior and microRNA biogenesis. Our co‐immunoprecipitation assay demonstrated a previously unrecognized molecular interaction between TWIST1 and p68 protein. Finally, we found that TWIST1 triggered SMC phenotypic switching and suppressed microRNA‐143/145 expression by promoting the proteasomal degradation of p68. These data suggest a novel role of TWIST1 in the regulation of SMC homeostasis by modulating p68/microRNA‐143/145 axis.

Dedifferentiation: inspiration for devising engineering strategies for regenerative medicine

Cell dedifferentiation is the process by which cells grow reversely from a partially or terminally differentiated stage to a less differentiated stage within their own lineage. This extraordinary phenomenon, observed in many physiological processes, inspires the possibility of developing new therapeutic approaches to regenerate damaged tissue and organs. Meanwhile, studies also indicate that dedifferentiation can cause pathological changes. In this review, we compile the literature describing recent advances in research on dedifferentiation, with an emphasis on tissue-specific findings, cellular mechanisms, and potential therapeutic applications from an engineering perspective. A critical understanding of such knowledge may provide fresh insights for designing new therapeutic strategies for regenerative medicine based on the principle of cell dedifferentiation.

Protective Role of RNA Helicase DEAD-Box Protein 5 in Smooth Muscle Cell Proliferation and Vascular Remodeling

RATIONALE

RNA helicases, highly conserved enzymes, are currently believed to be not only involved in RNA modulation, but also in other biological processes. We recently reported that RNA helicase DDX (DEAD-box protein)-5 is required for maintaining the homeostasis of vascular smooth muscle cells (SMCs). However, the expression and function of RNA helicase in vascular physiology and disease is unknown.

OBJECTIVE

To investigate the role of RNA helicase in vascular diseases.

METHODS AND RESULTS

We showed here that DDX-5 was the most abundant DEAD-box protein expressed in human and rodent artery, which mainly located in SMCs. It was demonstrated that DDX-5 levels were reduced in cytokine-stimulated SMCs and vascular lesions. DDX-5 knocking down or deficiency increased SMC proliferation and migration, whereas overexpression of DDX-5 prevented aberrant proliferation and migration of SMCs. Mechanistic studies revealed transcription factor GATA (GATA-binding protein)-6 as a novel downstream target of DDX-5, which directly interacted with GATA-6 and protected it from MDM (mouse double minute)-2-mediated degradation. Our ChIP assay identified a previously unreported binding of p27^Kip1 promoter to GATA-6. DDX-5 increased the recruitment of GATA-6 to p27^Kip1 promoter, which enhanced p27^Kip1 expression and maintained SMC quiescence. Finally, we showed exacerbated neointima formation in DDX-5 SMC-deficient mice after femoral artery injury, whereas overexpression of DDX-5 potently inhibited vascular remodeling in balloon-injured rat carotid artery.

CONCLUSIONS

These findings provide the first evidence for a role of RNA helicase DDX-5 in the protection against SMC proliferation, migration, and neointimal hyperplasia. Our data extend the fundamental role of RNA helicase beyond RNA modulation, which provides the basic information for new therapeutic strategies for vascular diseases.

MIF and insulin: Lifetime companions from common genesis to common pathogenesis

Pro-inflammatory nature of macrophage migration inhibitory factor (MIF) has been generally related to the propagation of inflammatory and autoimmune diseases. But this molecule possesses many other peculiar functions, unrelated to the immune system, among which is its supportive role in the post-translational modifications of insulin. In this way MIF enables proper insulin conformation within the pancreatic beta cell and its full activity. The inherent or acquired changes in MIF expression might therefore lead to different insulin processing and initiation of autoimmunity. The relation between MIF and insulin does not stop at this point; these two molecules continue to interact during pathological states characterized by inflammation and insulin resistance. In this context, MIF indirectly and negatively influences insulin action by boosting inflammatory environment and disabling target cells to respond to insulin. On the other side, insulin might interfere with MIF action as well, acting as an anti-inflammatory mediator. Therefore, the proper interaction between MIF and insulin is crucial for maintaining homeostasis, while anti-inflammatory therapies based on the systemic MIF blockage may disturb this balance. This review covers MIF-insulin relationship in the physiological and pathological conditions and discusses the approaches for MIF inhibition and their net effect specifically considering possible impact on insulin misfolding and the possible misinterpretation of previous results due to the discovery of MIF functional homolog D-dopachrome tautomerase.

Prolyl 4-Hydroxylase Domain Protein 3-Inhibited Smooth-Muscle-Cell Dedifferentiation Improves Cardiac Perivascular Fibrosis Induced by Obstructive Sleep Apnea

Background

Intermittent hypoxia (IH) induced by obstructive sleep apnea (OSA) is a leading factor affecting cardiovascular fibrosis. Under IH condition, smooth muscle cells (SMAs) respond by dedifferentiation, which is associated with vascular remodelling. The expression of prolyl 4-hydroxylase domain protein 3 (PHD3) increases under hypoxia. However, the role of PHD3 in OSA-induced SMA dedifferentiation and cardiovascular fibrosis remains uncertain.

Methods

We explored the mechanism of cardiovascular remodelling in C57BL/6 mice exposed to IH for 3 months and investigated the mechanism of PHD3 in improving the remodelling in vivo and vitro.

Results

In vivo remodelling showed that IH induced cardiovascular fibrosis via SMC dedifferentiation and that fibrosis improved when PHD3 was overexpressed. In vitro remodelling showed that IH induced SMA dedifferentiation, which secretes much collagen I. PHD3 overexpression in cultured SMCs reversed the dedifferentiation by degrading and inactivating HIF-1α.

Conclusion

OSA-induced cardiovascular fibrosis was associated with SMC dedifferentiation, and PHD3 overexpression may benefit its prevention by reversing the dedifferentiation. Therefore, PHD3 overexpression has therapeutic potential in disease treatment.

Th1-type immune responses to Porphyromonas gingivalis antigens exacerbate angiotensin II-dependent hypertension and vascular dysfunction

Background and Purpose

Emerging evidence indicates that hypertension is mediated by immune mechanisms. We hypothesized that exposure to Porphyromonas gingivalis antigens, commonly encountered in periodontal disease, can enhance immune activation in hypertension and exacerbate the elevation in BP, vascular inflammation and vascular dysfunction.

Experimental Approach

Th1 immune responses were elicited through immunizations using P. gingivalis lysate antigens (10 μg) conjugated with aluminium oxide (50 μg) and IL‐12 (1 μg). The hypertension and vascular endothelial dysfunction evoked by subpressor doses of angiotensin II (0.25 mg·kg⁻¹·day⁻¹) were studied, and vascular inflammation was quantified by flow cytometry and real‐time PCR.

Key Results

Systemic T‐cell activation, a characteristic of hypertension, was exacerbated by P. gingivalis antigen stimulation. This translated into increased aortic vascular inflammation with enhanced leukocyte, in particular, T‐cell and macrophage infiltration. The expression of the Th1 cytokines, IFN‐γ and TNF‐α, and the transcription factor, TBX21, was increased in aortas of P. gingivalis/IL‐12/aluminium oxide‐immunized mice, while IL‐4 and TGF‐β were unchanged. These immune changes in mice with induced T‐helper‐type 1 immune responses were associated with an enhanced elevation of BP and endothelial dysfunction compared with control mice in response to 2 week infusion of a subpressor dose of angiotensin II.

Conclusions and Implications

These results support the concept that Th1 immune responses induced by bacterial antigens such as P. gingivalis can increase sensitivity to subpressor pro‐hypertensive insults such as low‐dose angiotensin II, thus providing a mechanistic link between chronic infection, such as periodontitis, and hypertension.

Linked Articles

This article is part of a themed section on Immune Targets in Hypertension. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.12/issuetoc

Blockage of macrophage migration inhibitory factor (MIF) suppressed uric acid-induced vascular inflammation, smooth muscle cell de-differentiation, and remodeling

Hyperuricemia contributes to vascular injury and dysfunction, yet the potential mechanisms are not well understood. Uric acid (UA) has been found to stimulate macrophage migration inhibitory factor (MIF) up-regulation in renal tubules from rats subjected to UA-induced nephropathy. Given that MIF is able to induce vascular smooth muscle cell (VSMC) de-differentiation (from contractile state to a secretory state), we thus hypothesized that UA-induced vascular injury is via up-regulating of MIF in VSMCs, which enhancing vascular inflammation and VSMC transition. Within a mouse model of UA injection (500 mg/kg, twice/day, 14 days), we measured circulating and vascular MIF levels under UA stimulation at 6 h, day 1, and 14. We tested the efficacy of MIF inhibitor (10 mg/kg, twice/day, 14 days) on UA-induced vascular inflammation and remodeling. High plasma level of UA induced vascular MIF release into the plasma at acute phase. In the chronic phase, the protein level of MIF is up-regulated in the vessels. MIF inhibitor suppressed vascular inflammatory responses, repressed VSMC de-differentiation, and attenuated vascular remodeling and dysfunction following UA stimulation. Knockdown of MIF in cultured VSMCs repressed UA-induced de-differentiation. Our results provided a novel mechanism for MIF-mediated vascular injury in response to UA stimulation, and suggested that anti-MIF interventions may be of therapeutic value in hyperuricemic patients.

miR-5590-3p inhibited tumor growth in gastric cancer by targeting DDX5/AKT/m-TOR pathway

Recent evidence suggests that microRNAs play important roles in the negative post-transcriptional regulators with altered expression levels found in gastric cancer (GC). Therefore, we employed explore the anti-cancer miRNA and the potential mechanisms by which miRNAs modulate GC progression. We have predicted GC miRNA expression data sets in TargetScan. miR-5590-3p is higher in adjacent nonmalignant tissue than in cancer tissue in 42 pairs of GC tissues. Functional assays, CCK-8 and colony formation assay, were used to determine the Anti-cancer role of miR-5590-3p in human GC progression. In addition, Ago2-based RIP and dual-luciferase reporter assay were conducted to study the miR-5590-3p as a direct target of DDX5. Next, Xenograft nude mouse models were used to determine the role of miR-5590-3p in GC tumorigenicity in vivo. Upregulation of miR-5590-3p suppressed GC cell proliferation, whereas downregulation of miR-5590-3p promoted GC proliferation in vitro. Furthermore, we identified DDX5 as a direct target of miR-5590-3p, and that the biological function of miR-5590-3p during GC progression in vitro and in vivo is through the DDX5/AKT/m-TOR pathway and downstream cyclinD1 and CDK2 expression. Finally, we confirmed the effect of miR-5590-3p directly targeting DDX5 on the development of gastric cancer through salvage experiments in vivo and in vitro.

Involvement of CD8+ T cell subsets in early response to vascular injury in patients with peripheral artery disease in vivo

AIMS

Adaptive immunity is critical in vascular remodelling following arterial injury. We hypothesized that acute changes in T cells at a percutaneous transluminal angioplasty (PTA) site could serve as an index of their potential interaction with the injured vascular wall.

METHODS AND RESULTS

T cell subsets were characterised in 45 patients with Rutherford 3-4 peripheral artery disease (PAD) undergoing PTA. Direct angioplasty catheter blood sampling was performed before and immediately after the procedure. PTA was associated with an acute reduction of α/β-TcR CD8+ T cells. Further characterisation revealed significant reduction in pro-atherosclerotic CD28nullCD57+ T cells, effector (CD45RA+CCR7-) and effector memory (CD45RA-CCR7-) cells, in addition to cells bearing activation (CD69, CD38) and tissue homing/adhesion markers (CD38, CCR5).

CONCLUSIONS

The acute reduction observed here is likely due to the adhesion of cells to the injured vascular wall, suggesting that immunosenescent, activated effector CD8+ cells have a role in the early vascular injury immune response following PTA in PAD patients.