MIF/CD74 axis participates in inflammatory activation of Schwann cells following sciatic nerve injury

Progress in the development of macrophage migration inhibitory factor small-molecule inhibitors

Macrophage migration inhibitory factor (MIF) functions as a critical cytokine regulating inflammatory and immune responses. Extensive research has demonstrated its involvement in the progression of various cancers, autoimmune diseases, and inflammatory disorders, establishing it as a pivotal target for anti-inflammatory and anticancer interventions. Therapeutic strategies aimed at MIF primarily focus on suppressing its activity through small molecule inhibitors and natural compounds. This review synthesizes current knowledge on MIF, encompassing its structural characteristics, enzymatic functions, signaling pathways, and roles in disease pathogenesis. Additionally, it provides an in-depth analysis of recent advancements in MIF inhibitor development, including design methodologies, structure-activity relationships, advanced eutectic analysis techniques, and key experimental findings. The discussion aims to support the development of safer, more effective, and highly selective small molecule inhibitors targeting MIF.

100% oxygen mobilizes stem cells and up-regulates MIF and APRIL in humans: a new point on the hormetic dose curve

Introduction

The aim of the current study was to test normobaric 100% oxygen (NBO) (PiO2 = 713 mmHg) for stem cell mobilization and cytokine modulation. Although current oxygen therapy (PiO2 = 1,473-2,233 mmHg) is well known to mobilize stem cells and modulate cytokine, little is known about NBO and its place on the low dose stimulation phase of the hormetic dose curve of oxygen. We asked the question, will NBO mobilize stem cells and modulate cytokines. A positive outcome presents the potential to create and refine oxygen treatment protocols, expand access, and optimize patient outcomes.

Methods

Healthy 30-35-year-old volunteers were exposed to 100% normobaric oxygen for 60 min, M-F, for 10 exposures over 2 weeks. Venous blood samples were collected at four time points: 1) prior to the first exposure (serving as the control for each subject), 2) immediately after the first exposure (to measure the acute effect), 3) immediately before the ninth exposure (to measure the chronic effect), and 4) three days after the final exposure (to assess durability). Blinded scientists used flow cytometry to gate and quantify the Stem Progenitor Cells (SPCs).

Results

CD45dim/CD34+/CD133+ and CD45+/CD34+/CD133+ were significantly mobilized following nine daily one-hour exposures to normobaric 100% oxygen. Conversely CD45-/CD34+/CD133+, CD45-/CD34+/CD133- and CD45-/CD34-/CD133+ phenotypes were downregulated suggesting differentiation into more mature phenotypes. The CD133+ phenotype exhibited a maturing from CD45- to CD45dim stem cells. CD45-/CD34, CD45-/CD31 and CD45-/CD105 were downregulated with no changes in related CD45dim and CD45+ phenotypes. The cytokines "macrophage migration inhibitory factor" (MIF) and "a proliferation inducing ligand" (APRIL) were significantly upregulated.

Conclusion

This study demonstrates that 100% normobaric oxygen mobilizes stem cells and upregulates the expression of the inflammatory cytokines marking a new point on the low dose stimulation phase of the hormetic dose curve of oxygen.

The macrophage migration inhibitory factor/CD74 axis in traumatic spinal cord injury: lessons learned from animal and human studies

Traumatic spinal cord injury (SCI) is a severe condition leading to long-term impairment of motor, sensory, and autonomic functions. Following the initial injury, a series of additional events is initiated further damaging the spinal cord. During this secondary injury phase, both an inflammatory and immune modulatory response are triggered that have damaging and anti-inflammatory properties, respectively. The proinflammatory cytokine macrophage migration inhibitory factor (MIF) and its receptor CD74 have been extensively studied in traumatic SCI. MIF expression is increased in spinal cord tissue after experimental SCI, mainly in astrocytes and microglia, as well as in the plasma of SCI patients. Functionally, MIF and CD74 were shown to regulate astrocyte viability, proliferation and cholesterol metabolism, microglia migration, and neuronal viability. Moreover, inhibition of the MIF/CD74 axis improved the functional recovery of SCI animals. We provide a detailed overview of studies analyzing the role of MIF and CD74 in traumatic SCI. We describe results from animal studies, using rat and mouse models for SCI, and human studies. Furthermore, we propose a new path for investigation, focused on B cells, that might lead to a better understanding of how MIF and CD74 contribute to the secondary injury cascade following traumatic SCI.

Macrophage migration inhibitor factor (MIF): Potential role in cognitive impairment disorders

Macrophage migration inhibitory factor (MIF) is a cytokine in the immune system, participated in both innate and adaptive immune responses. Except from immune cells, MIF is also secreted by a variety of non-immune cells, including hematopoietic cells, endothelial cells (ECs), and neurons. MIF plays a crucial role in various diseases, such as sepsis, rheumatoid arthritis, acute kidney injury, and neurodegenerative diseases. The role of MIF in the neuropathogenesis of cognitive impairment disorders is emphasized, as it recruits multiple inflammatory mediators, leading to activating microglia or astrocyte-derived neuroinflammation. Furthermore, it contributes to the cell death of neurons and ECs with the binding of apoptosis-inducing factor (AIF) through parthanatos-associated apoptosis-inducing factor nuclease (PAAN) / MIF pathway. This review comprehensively delves into the relationship between MIF and the neuropathogenesis of cognitive impairment disorders, providing a series of emerging MIF-targeted pharmaceuticals as potential treatments for cognitive impairment disorders.

5-HMF attenuates inflammation and demyelination in experimental autoimmune encephalomyelitis mice by inhibiting the MIF-CD74 interaction

The neuroprotective role of 5-hydroxymethyl-2-furfural (5-HMF) has been demonstrated in a variety of neurological diseases. The aim of this study is to investigate the effect of 5-HMF on multiple sclerosis (MS). IFN-γ-stimulated murine microglia (BV2 cells) are considered a cell model of MS. With 5-HMF treatment, microglial M1/2 polarization and cytokine levels are detected. The interaction of 5-HMF with migration inhibitory factor (MIF) is predicted using online databases. The experimental autoimmune encephalomyelitis (EAE) mouse model is established, followed by a 5-HMF injection. The results show that 5-HMF facilitates IFN-γ-stimulated microglial M2 polarization and attenuates the inflammatory response. According to the network pharmacology and molecular docking results, 5-HMF has a binding site for MIF. Further results show that blocking MIF activity or silencing CD74 enhances microglial M2 polarization, reduces inflammatory activity, and prevents ERK1/2 phosphorylation. 5-HMF inhibits the MIF-CD74 interaction by binding to MIF, thereby inhibiting microglial M1 polarization and enhancing the anti-inflammatory response. 5-HMF ameliorates EAE, inflammation, and demyelination in vivo. In conclusion, our research indicates that 5-HMF promotes microglial M2 polarization by inhibiting the MIF-CD74 interaction, thereby attenuating inflammation and demyelination in EAE mice.

Expression and Correlation of MIF and ERK1/2 in Liver Cirrhosis and Hepatocellular Carcinoma Induced by Hepatitis B

Objective

To detect expression and phosphorylation level of macrophage migration inhibitor (MIF) and extracellular-regulated kinases 1 and 2 (ERK1/2) in hepatitis B-induced liver cirrhosis (HBILC) and hepatocellular carcinoma (HCC) with a background of HBILC and analyze the correlation of MIF and ERK1/2 with HBILC and HCC.

Methods

Twenty cases of normal liver tissues were collected as a control group, and 48 specimens of HBILC tissues and 48 specimens of HCC tissues were collected as the experimental group, which were assigned as the HBILC group and HCC group, respectively. All tissue specimens were processed into tissue chips. The expressions of MIF, ERK1/2, and their phosphorylated proteins were detected via immunohistochemistry, and MIF and ERK1/2 nucleic acid expressions were detected by in situ hybridization. The results were statistically analyzed using the chi-square test.

Results

Proteins and nucleic acids of MIF and ERK1/2 presented low expression in the control group and high expression in the HBILC group and HCC group. MIF expression in the three groups was 25.0%, 75.0%, and 79.17%, respectively, while that of the nucleic acids was 25.0%, 70.83%, and 68.75%, respectively. Expression of ERK1/2 in the three groups was 40.0%, 60.42%, and 81.25%, respectively, and that of nucleic acids was 40.0%, 79.17%, and 77.08%. Expression of pERK1/2 was low in the control and HBILC group and high in the HCC group. Expression of pERK1/2 in the three groups was 20%, 45.83%, and 75%, respectively. Expression of pERK1/2 in the HCC group was significantly different from that in the HBILC and control group (P<0.05), but the difference between the HBILC group and control group was not statistically significant (P>0.05).

Conclusion

Occurrence and development of HBILC and HCC are not only related to the high expression of MIF but also closely related to the activation of the ERK1/2 signaling pathway.

Comparison of human skin- and nerve-derived Schwann cells reveals many similarities and subtle genomic and functional differences

Skin is an easily accessible tissue and a rich source of Schwann cells (SCs). Toward potential clinical application of autologous SC therapies, we aim to improve the reliability and specificity of our protocol to obtain SCs from small skin samples. As well, to explore potential functional distinctions between skin-derived SCs (Sk-SCs) and nerve-derived SCs (N-SCs), we used single-cell RNA-sequencing and a series of in vitro and in vivo assays. Our results showed that Sk-SCs expressed typical SC markers. Single-cell sequencing of Sk- and N-SCs revealed an overwhelming overlap in gene expression with the exception of HLA genes which were preferentially up-regulated in Sk-SCs. In vitro, both cell types exhibited similar levels of proliferation, migration, uptake of myelin debris and readily associated with neurites when co-cultured with human iPSC-induced motor neurons. Both exhibited ensheathment of multiple neurites and early phase of myelination, especially in N-SCs. Interestingly, dorsal root ganglion (DRG) neurite outgrowth assay showed substantially more complexed neurite outgrowth in DRGs exposed to Sk-SC conditioned media compared to those from N-SCs. Multiplex ELISA array revealed shared growth factor profiles, but Sk-SCs expressed a higher level of VEGF. Transplantation of Sk- and N-SCs into injured peripheral nerve in nude rats and NOD-SCID mice showed close association of both SCs to regenerating axons. Myelination of rodent axons was observed infrequently by N-SCs, but absent in Sk-SC xenografts. Overall, our results showed that Sk-SCs share near-identical properties to N-SCs but with subtle differences that could potentially enhance their therapeutic utility.

Deciphering the Intercellular Communication Between Immune Cells and Altered Vascular Smooth Muscle Cell Phenotypes in Aortic Aneurysm From Single-Cell Transcriptome Data

Background

Vascular smooth muscle cell (VSMC) phenotype switching has been preliminarily found in aortic aneurysms. However, two major questions were raised: (1) What factors drive phenotypic switching of VSMCs in aortic aneurysms? (2) What role does VSMC phenotype transformation play in aortic aneurysms? We speculated that the interaction between infiltrated immune cells and VSMCs played a pivotal role in aortic aneurysm expansion.

Materials and Methods

We obtained single-cell transcriptome data GSE155468 that incorporate eight aortic aneurysm samples and three normal aorta samples. A standard single-cell analysis procedure was performed by Seurat (v3.1.2) for identifying the general cell components. Subsequently, VSMCs were extracted separately and re-clustered for identifying switched VSMC phenotypes. VSMC phenotype annotation was relied on the definitions of specific VSMC phenotypes in published articles. Vital VSMC phenotypes were validated by immunofluorescence. Next, identified immune cells and annotated vital VSMC phenotypes were extracted for analyzing the intercellular communication. R package CellChat (v1.1.3) was used for investigating the communication strength, signaling pathways, and communication patterns between various VSMC phenotypes and immune cells.

Result

A total of 42,611 cells were identified as CD4 + T cells, CD8 + T cells, VSMC, monocytes, macrophages, fibroblasts, endothelial cells, and B cells. VSMCs were further classified into contractile VSMCs, secreting VSMCs, macrophage-like VSMCs, mesenchymal-like VSMCs, adipocyte-like VSMCs, and T-cell-like VSMCs. Intercellular communication analysis was performed between immune cells (macrophages, B cells, CD4 + T cells, CD8 + T cells) and immune related VSMCs (macrophage-like VSMCs, mesenchymal-like VSMCs, T-cell-like VSMCs, contractile VSMCs). Among selected cell populations, 27 significant signaling pathways with 61 ligand–receptor pairs were identified. Macrophages and macrophage-like VSMCs both assume the roles of a signaling sender and receiver, showing the highest communication capability. T cells acted more as senders, while B cells acted as receivers in the communication network. T-cell-like VSMCs and contractile VSMCs were used as senders, while mesenchymal-like VSMCs played a poor role in the communication network. Signaling macrophage migration inhibitory factor (MIF), galectin, and C-X-C motif chemokine ligand (CXCL) showed high information flow of intercellular communication, while signaling complement and chemerin were completely turned on in aortic aneurysms. MIF and galectin promoted VSMC switch into macrophage-like phenotypes, CXCL, and galectin promoted VSMCs transform into T-cell-like phenotypes. MIF, galectin, CXCL, complement, and chemerin all mediated the migration and recruitment of immune cells into aortic aneurysms.

Conclusion

The sophisticated intercellular communication network existed between immune cells and immune-related VSMCs and changed as the aortic aneurysm progressed. Signaling MIF, galectin, CXCL, chemerin, and complement made a significant contribution to aortic aneurysm progression through activating immune cells and promoting immune cell migration, which could serve as the potential target for the treatment of aortic aneurysms.

Multifaceted interconnections between macrophage migration inhibitory factor and psychiatric disorders

Inflammation is involved in the pathogenesis of psychiatric disorders. Many previous studies have defined the important roles of inflammatory factors in the pathogenesis, diagnosis, and treatment outcomes of psychiatric disorders. Macrophage migration inhibitory factor (MIF), a pro-inflammatory factor, has been gradually recognized to be involved in the development of neurological diseases in recent years. Our current review focuses on discussing the potential beneficial and detrimental roles of MIF in psychiatric disorders. We will provide new mechanistic insights for the development of potential diagnostic and therapeutic biomarkers based on MIF for psychiatric diseases.

Gene correlation network analysis to identify regulatory factors in sciatic nerve injury

BACKGROUND

Sciatic nerve injury (SNI), which frequently occurs under the traumatic hip and hip fracture dislocation, induces serious complications such as motor and sensory loss, muscle atrophy, or even disabling. The present work aimed to determine the regulating factors and gene network related to the SNI pathology.

METHODS

Sciatic nerve injury dataset GSE18803 with 24 samples was divided into adult group and neonate group. Weighted gene co-expression network analysis (WGCNA) was carried out to identify modules associated with SNI in the two groups. Moreover, differentially expressed genes (DEGs) were determined from every group, separately. Subsequently, co-expression network and protein-protein interaction (PPI) network were overlapped to identify hub genes, while functional enrichment and Reactome analysis were used for a comprehensive analysis of potential pathways. GSE30165 was used as the test set for investigating the hub gene involvement within SNI. Gene set enrichment analysis (GSEA) was performed separately using difference between samples and gene expression level as phenotype label to further prove SNI-related signaling pathways. In addition, immune infiltration analysis was accomplished by CIBERSORT. Finally, Drug-Gene Interaction database (DGIdb) was employed for predicting the possible therapeutic agents.

RESULTS

14 SNI status modules and 97 DEGs were identified in adult group, while 15 modules and 21 DEGs in neonate group. A total of 12 hub genes was overlapping from co-expression and PPI network. After the results from both test and training sets were overlapped, we verified that the ten real hub genes showed remarkably up-regulation within SNI. According to functional enrichment of hub genes, the above genes participated in the immune effector process, inflammatory responses, the antigen processing and presentation, and the phagocytosis. GSEA also supported that gene sets with the highest significance were mostly related to the cytokine-cytokine receptor interaction. Analysis of hub genes possible related signaling pathways using gene expression level as phenotype label revealed an enrichment involved in Lysosome, Chemokine signaling pathway, and Neurotrophin signaling pathway. Immune infiltration analysis showed that Macrophages M2 and Regulatory T cells may participate in the development of SNI. At last, 25 drugs were screened from DGIdb to improve SNI treatment.

CONCLUSIONS

The gene expression network is determined in the present work based on the related regulating factors within SNI, which sheds more light on SNI pathology and offers the possible biomarkers and therapeutic targets in subsequent research.

Macrophage migration inhibitory factor modulates cytokine expression in the trophoblast cell line HTR-8/SVneo

Extravillous trophoblasts are specific placental cells that invade the uterine stroma and spiral arteries modifying and adjusting them to pregnancy. Many pregnancy pathologies are associated with impairment of this process, including preeclampsia and intrauterine growth restriction, among others. Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine that is abundant at the fetomaternal interface. Previous results from our group showed that MIF participates in trophoblast invasion and modulates the expression of molecules known to mediate stromal and endovascular trophoblast invasion. In this study we investigated the possibility that MIF could act as a regulator of cytokines known to modulate trophoblast invasion using the normal extravillous trophoblast-derived cell line HTR-8/SVneo. Expression of trophoblast MIF was attenuated by MIF mRNA-specific small interfering RNAs. Cytokine expression was assessed at the mRNA and protein levels using real-time quantitative polymerase chain reaction and flow cytometry respectively. Knockdown of MIF led to a significant decrease in mRNA for IL-1β (IL1B) and IL-8 (CXCL8) and interleukin (IL)-8 protein. The addition of recombinant human MIF to cell culture medium increased IL-6 after 24h treatment and IL-6 and IL-8 after 72h treatment. Cell viability was not affected by MIF silencing or rhMIF treatment. The results of this study imply that at least some of the effects of MIF on trophoblast invasion could be mediated through autocrine or paracrine modulation of trophoblast cytokine production.

CD74, a novel predictor for bronchopulmonary dysplasia in preterm infants

Bronchopulmonary dysplasia (BPD) remains a major complication and accounts for high morbidity and mortality of preterm infants. The present study aimed to identify the key genes in the development of BPD and to provide some new insights into the pathogenesis of BPD. The GSE108754 dataset was downloaded from Gene Expression Omnibus database containing 5 samples of BPD patients and 6 of non-BPD infants. The differentially expressed genes (DEGs) between BPD and non-BPD patients were identified by R software. The pathway and function enrichment analyses were performed through Database for Annotation Visualization and Integrated Discovery website. The protein-protein interaction network for DEGs was established by Cytoscape software and the most highly connected module was selected through MCODE plugin. Furthermore, the clinical sample verification among 25 BPD patients and 10 non-BPD infants was carried out in our center. Finally, based on the results above, the gene set enrichment analysis focusing on CD74 upregulated status was employed. Totally, 189 DEGs including 147 upregulated genes and 42 downregulated genes between BPD and non-BPD patients were screened out. The pathway and function enrichments revealed these DEGs were mainly enriched in asthma, intestinal immune network for IgA production, antigen processing and presentation and immune response. Thirteen DEGs (CD74, HLA-DMA, HLA-DRA, HLA-DMB, HLA-DOB, HLA-DQA1, HLA-DRB5, HLA-DPA1, HLA-DOA, HLA-DPB1, HLA-DQB2, HLA-DQA2, and HLA-DQB1) were determined as hub genes. The mRNA expression levels of the 13 hub genes were tested by quantitative real-time polymerase chain reaction among our clinical samples. Eventually, CD74 was confirmed to be the most significant highly expressed in BPD samples (P < .001) and its expression level was negatively correlated with gestational age (r = -0.653) and birth weight (r = -0.675). The gene set enrichment analysis results showed the gene sets associated with lupus erythematosus, viral myocarditis, immune network for IgA production, graft versus host disease, cell adhesion molecules and so no were differentially enriched with the phenotype of high-expression CD74. In conclusion, CD74 may serve to predict the BPD development and provide a new therapeutic target for BPD.

Migration inhibitory factor in spinal tuberculosis: -173G/C polymorphisms, and transcript and protein levels in a northern province of China

The aim of this study was to elucidate the possible association between migration inhibitory factor (MIF)-173G/C gene polymorphisms and transcript and plasma levels of MIF in spinal tuberculosis (TB) patients. Clinical data were collected from 254 spinal TB patients and 262 healthy controls participating in the study. The genotype of the MIF-173G/C gene was amplified by polymerase chain reaction and genotyped by DNA sequencing technology. The level of mRNA expression was determined by real-time polymerase chain reaction and MIF plasma levels were measured by a solid-phase enzyme-linked immunosorbent assay. The frequency of the C allele and GC+CC genotype in MIF-173G/C was over-represented in spinal TB patients. The mean MIF mRNA level in spinal TB patients and patients with the GG and GC+CC genotype were significantly lower than controls; however, our study also indicated that the MIF concentration in spinal TB patients and patients with the GG and GC+CC genotypes were significantly higher than controls. Spinal TB patients with the GG genotype had higher MIF plasma levels than patients with the GC+CC genotype. The C-reactive protein level and erythrocyte sedimentation rate was correlated with the MIF plasma level. In summary, the association between the MIF-173G/C genetic polymorphism, reduced transcript and increased plasma levels of MIF in spinal TB patients, and MIF may play an important role in the occurrence, development, and damage of spinal TB in the northern Province population of China.

Role of MIF Cytokine/CD74 Receptor Pathway in Protecting Against Injury and Promoting Repair

Wound healing after an injury is essential for life. An in-depth understanding of the healing process is necessary to ultimately improve the currently limited treatment options for patients suffering as a result of damage to various organs and tissues. Injuries, even the most minor, trigger an inflammatory response that protects the host and activates repair pathways. In recent years, substantial progress has been made in delineating the mechanisms by which inflammatory cytokines and their receptors facilitate tissue repair and regeneration. This mini review focuses on emerging literature on the role of the cytokine macrophage migration inhibitory factor (MIF) and its cell membrane receptor CD74, in protecting against injury and promoting healing in different parts of the body.

Deciphering immune mechanisms in chronic inflammatory demyelinating polyneuropathies

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an autoimmune disease of the peripheral nerves that presents with either chronic progression or relapsing disease. Recent studies in samples from patients with CIDP and mouse models have delineated how defects in central (thymic) and peripheral (extrathymic) immune tolerance mechanisms can cause PNS autoimmunity. Notably, nerve parenchymal cells actively contribute to local autoimmunity and also control disease outcome. Here, we outline how emerging technologies increasingly enable an integrated view of how immune cells and PNS parenchymal cells communicate in CIDP. We also relate the known heterogeneity of clinical presentation with specific underlying mechanisms. For example, a severe subtype of CIDP with tremor is associated with pathogenic IgG4 autoantibodies against nodal and paranodal proteins. An improved understanding of pathogenic mechanisms in CIDP will form the basis for more effective mechanism-based therapies.

Macrophage migration inhibitory factor and its binding partner HTRA1 are expressed by olfactory ensheathing cells

Macrophage migration inhibitory factor (MIF) is an important regulator of innate immunity with key roles in neural regeneration and responses to pathogens, amongst a multitude of other functions. The expression of MIF and its binding partners has been characterised throughout the nervous system, with one key exception: the primary olfactory nervous system. Here, we showed in young mice (postnatal day 10) that MIF is expressed in the olfactory nerve by olfactory ensheathing glial cells (OECs) and by olfactory nerve fibroblasts. We also examined the expression of potential binding partners for MIF, and found that the serine protease HTRA1, known to be inhibited by MIF, was also expressed at high levels by OECs and olfactory fibroblasts in vivo and in vitro. We also demonstrated that MIF mediated segregation between OECs and J774a.1 cells (a monocyte/macrophage cell line) in co-culture, which suggests that MIF contributes to the fact that macrophages are largely absent from olfactory nerve fascicles. Phagocytosis assays of axonal debris demonstrated that MIF strongly stimulates phagocytosis by OECs, which indicates that MIF may play a role in the response of OECs to the continual turnover of olfactory axons that occurs throughout life.