HIF-1α promotes astrocytic production of macrophage migration inhibitory factor following spinal cord injury.

BACKGROUND: Macrophage migration inhibitory factor (MIF) is an important mediator of neuropathology in various central nervous system (CNS) diseases. However, little is known about its inducers for production from the nerve cells, as well as the underlying regulatory mechanism. Injury-induced HIF-1α has been shown to exacerbate neuroinflammation by activating multiple downstream target molecules. It is postulated that HIF-1α is involved in the regulation of MIF following spinal cord injury (SCI). METHODS: SCI model of Sprague-Dawley rats was established by cord contusion at T8-T10. The dynamic changes of HIF-1α and MIF protein levels at lesion site of rat spinal cord were determined by Western blot. The specific cell types of HIF-1α and MIF expression were examined by immunostaining. Primary astrocytes were isolated from the spinal cord, cultured and stimulated with various agonist or inhibitor of HIF-1α for analysis of HIF-1α-mediated expression of MIF. Luciferase report assay was used to determine the relationship between HIF-1α and MIF. The Basso, Beattie, and Bresnahan (BBB) locomotor scale was used to assess the locomotor function following SCI. RESULTS: The protein levels of HIF-1α and MIF at lesion site were significantly elevated by SCI. Immunofluorescence demonstrated that both HIF-1α and MIF were abundantly expressed in the astrocytes of the spinal cord. By using various agonists or inhibitors of HIF-1α, it was shown that HIF-1α sufficiently induced astrocytic production of MIF. Mechanistically, HIF-1α promoted MIF expression through interaction with MIF promoter. Inhibition of HIF-1α activity using specific inhibitor markedly reduced the protein levels of MIF at lesion site following SCI, which in turn favored for the functional recovery. CONCLUSION: SCI-induced activation of HIF-1α is able to promote MIF production from astrocytes. Our results have provided new clues for SCI-induced production of DAMPs, which may be helpful for clinical treatment of neuroinflammation.

Macrophage Migration Inhibitory Factor Promotes Expression of Matrix Metalloproteinases 1 and 3 in Spinal Cord Astrocytes following Gecko Tail Amputation.

BACKGROUND: The matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases that play a variety of physiological and pathological roles in development, remodeling of tissues and diseases, mainly through degradation of various components of the extracellular matrix (ECM). Particularly, the MMPs have increasingly been found to mediate neuropathology following spinal cord injury (SCI). Proinflammatory mediators are potent activators of the MMPs. However, how the spinal cord regenerative vertebrates circumvent MMPs-mediated neuropathogenesis following SCI remains unclear. METHODS: Following the establishment of gecko tail amputation model, the correlation of MMP-1 (gMMP-1) and MMP-3 (gMMP-3) expression with that of macrophage migration inhibitory factor in gecko (gMIF) was assayed by RT-PCR, Western blot and immunohistochemistry. Transcriptome sequencing of primary astrocytes was performed to analyze the intracellular signal transduction of macrophage migration inhibitory factor (MIF). The effects of MMP-1 and MMP-3 induced by MIF on astrocyte migration were assessed by transwell migration assay. RESULTS: The expression of gMIF significantly increased at lesion site of the injured cord, in parallel with those of gMMP-1 and gMMP-3 in the gecko astrocytes (gAS). Transcriptome sequencing and in vitro cell model revealed that gMIF efficiently promoted the expression of gMMP-1 and gMMP-3 in gAS, which in turn contributed to the migration of gAS. Inhibition of gMIF activity following gecko SCI remarkably attenuated astrocytic expression of the two MMPs, and further influenced gecko tail regeneration. CONCLUSIONS: Gecko SCI following tail amputation promoted production of gMIF, which induced the expression of gMMP-1 and gMMP-3 in gAS. The gMIF-mediated gMMP-1 and gMMP-3 expression was involved in gAS migration and successful tail regeneration.

[Effect of Trichomonas vaginalis macrophage migration inhibitory factor on THP-1 macrophages].

OBJECTIVE: To investigate the effect of Trichomonas vaginalis macrophage migration inhibitory factor (TvMIF) on THP-1 macrophages. METHODS: Recombinant TvMIF protein was prokaryotic expressed and purified, and endotoxin was removed after identification. Following exposure to TvMIF at concentrations of 0, 1, 5, 10, 50 and 100 ng/mL, the cytotoxicity of the recombinant TvMIF protein to THP-1 macrophages was tested using cell counting kit (CCK)-8 assay, and the apoptosis of THP-1 macrophages and reactive oxygen species (ROS) were detected using flow cytometry. The relative expression of nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3), caspase-1, interleukin-1ß (IL-1ß) and IL-18 genes was quantified using real-time fluorescent quantitative PCR (qPCR) assay, and the expression of caspase-1, NLRP3, gasdermin D (GSDMD), gasdermin D N-terminal (GSDMD-NT) and pro-IL-1ß proteins were determined using Western blotting assay. RESULTS: Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) displayed successful expression and purification of the recombinant TvMIF protein with a molecular weight of 15.5 kDa, and the endotoxin activity assay showed the successful removal of endotoxin in the recombinant TvMIF protein (endotoxin concentration < 0.1 EU/mL), which was feasible for the subsequent studies on protein functions. Flow cytometry revealed that the recombinant TvMIF protein at a concentration of 10 ng/mL and less promoted the apoptosis of THP-1 macrophages, and the highest apoptotic rate of THP-1 macrophages was seen following exposure to the recombinant TvMIF protein at a concentration of 5 ng/mL, while the recombinant TvMIF protein at concentrations of 50 and100 ng/mL inhibited the apoptosis of THP-1 macrophages. Exposure to the recombinant TvMIF protein at a concentration 1 ng/mL resulted in increased ROS levels in THP-1 macrophages. qPCR assay quantified significantly elevated caspase-1, NLRP3, IL-18 and IL-1ß expression in THP-1 macrophages 8 hours post-treatment with the recombinant TvMIF protein at a concentration 1 ng/mL, and Western blotting determined increased caspase-1, NLRP3, pro-IL-1ß, GSDMD and GSDMD-NT protein expression in THP-1 macrophages following exposure to the recombinant TvMIF protein at a concentration 1 ng/mL. Pretreatment with MCC950 significantly reduced GSDMD and GSDMD-NT protein expression. CONCLUSIONS: High-concentration recombinant TvMIF protein inhibits macrophage apoptosis, while low-concentration recombinant TvMIF protein activates NLRP3 inflammasome and promotes macrophage pyroptosis.

Obacunone targets macrophage migration inhibitory factor (MIF) to impede osteoclastogenesis and alleviate ovariectomy-induced bone loss.

INTRODUCTION: Osteoporosis is the most common bone disorder where the hyperactive osteoclasts represent the leading role during the pathogenesis. Targeting hyperactive osteoclasts is currently the primary therapeutic strategy. However, concerns about the long-term efficacy and side effects of current frontline treatments persist. Alternative therapeutic agents are still needed. OBJECTIVES: Obacunone (OB) is a small molecule with a broad spectrum of biological activities, particularly antioxidant and anti-inflammatory effects. This study aims to examine OB's therapeutic potential on osteoporosis and explore the rudimentary mechanisms. METHODS: Osteoclast formation and osteoclastic resorption assays were carried out to examine OB's inhibitory effects in vitro, followed by the in-vivo studies of OB's therapeutic effects on ovariectomy-induced osteoporotic preclinical model. To further study the underlying mechanisms, mRNA sequencing and analysis were used to investigate the changes of downstream pathways. The molecular targets of OB were predicted, and in-silico docking analysis was performed. Ligand-target binding was verified by surface plasmon resonance (SPR) assay and Western Blotting assay. RESULTS: The results indicated that OB suppressed the formation of osteoclast and its resorptive function in vitro. Mechanistically, OB interacts with macrophage migration inhibitory factor (MIF) which attenuates receptor activator of nuclear factor kappa B (NF-κB) ligand (RANKL)-induced signaling pathways, including reactive oxygen species (ROS), NF-κB pathway, and mitogen-activated protein kinases (MAPKs). These effects eventually caused the diminished expression level of the master transcriptional factor of osteoclastogenesis, nuclear factor of activated T cells 1 (NFATc1), and its downstream osteoclast-specific proteins. Furthermore, our data revealed that OB alleviated estrogen deficiency-induced osteoporosis by targeting MIF and thus inhibiting hyperactive osteoclasts in vivo. CONCLUSION: These results together implicated that OB may represent as a therapeutic candidate for bone disorders caused by osteoclasts, such as osteoporosis.

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.

Macrophage Migration Inhibitory Factor (MIF) Promotes Increased Proportions of the Highly Permissive Th17-like Cell Profile during HIV Infection.

In this study, we evaluate the role of the MIF/CD74 axis in the functionality of CD4+ T lymphocytes (CD4TL) during HIV infection. MDMs from healthy donors were infected with a R5-tropic or Transmitted/Founder (T/F) HIV strain. At day 11 post-MDM infection, allogeneic co-cultures with uninfected CD4TLs plus MIF stimulus were performed. Cytokine production was evaluated by ELISA. MIF plasma levels of people with HIV (PWH) were evaluated by ELISA. The phenotype and infection rate of CD4TLs from PWH were analyzed after MIF stimulus. Intracellular cytokines and transcription factors were evaluated by flow cytometry. Data were analyzed by parametric or non-parametric methods. The MIF stimulation of HIV-infected MDMs induced an increased expression of IL-6, IL-1ß and IL-8. In CD4TL/MDM co-cultures, the MIF treatment increased IL-17A/RORγt-expressing CD4TLs. Higher concentrations of IL-17A in supernatants were also observed. These results were recapitulated using transmitted/founder (T/F) HIV-1 strains. The MIF treatment appeared to affect memory CD4TLs more than naïve CD4TLs. MIF blocking showed a negative impact on IL17A+CD4TL proportions. Higher MIF concentrations in PWH-derived plasma were correlated with higher IL-17A+CD4TL percentages. Finally, MIF stimulation in PWH-derived PBMCs led to an increase in Th17-like population. MIF may contribute to viral pathogenesis by generating a microenvironment enriched in activating mediators and Th17-like CD4TLs, which are known to be highly susceptible to HIV-1 infection and relevant to viral persistence. These observations establish a basis for considering MIF as a possible therapeutic target.

Astaxanthin ameliorates serum level and spinal expression of macrophage migration inhibitory factor following spinal cord injury.

Astaxanthin (AST) is a lipid-soluble carotenoid with antioxidant and anti-inflammatory properties. Previous reports demonstrated the promising effects of AST on spinal cord injury (SCI)-induced inflammation and sensory-motor dysfunction. Macrophage migration inhibitory factor (MIF), as a cytokine, plays a critical role in the inflammatory phase of SCI. The aim of this study was to evaluate the effects of AST on post-SCI levels of MIF in serum and spinal cord. The possible correlation between MIF and mechanical pain threshold was also assessed. Adult male rats were subjected to a severe compression spinal injury and 30 min later were treated with AST (Intrathecal, 2 nmol) or vehicle. Neuropathic pain was assessed by von Frey filaments before the surgery, and then on days 7, 14, 21, and 28 post-SCI. Western blot and ELISA were used to measure the serum level and spinal expression of MIF following SCI in the same time points. AST treatment significantly attenuated the SCI-induced dysregulations in the serum levels and tissue expression of MIF. A negative correlation was observed between mechanical pain threshold and serum MIF level (r = -0.5463, P < 0.001), as well as mechanical pain threshold and spinal level of MIF (r = -0.9562; P < 0.001). AST ameliorates SCI-induced sensory dysfunction, probably through inhibiting MIF-regulated inflammatory pathways.

Neuroprotective Effect of Macrophage Migration Inhibitory Factor (MIF) in a Mouse Model of Ischemic Stroke.

The mechanism of the neuroprotective effect of the macrophage migration inhibitory factor (MIF) in vivo is unclear. We investigated whether the MIF promotes neurological recovery in an in vivo mouse model of ischemic stroke. Transient middle cerebral artery occlusion (MCAO) surgery was performed to make ischemic stroke mouse model. Male mice were allocated to a sham vehicle, a sham MIF, a middle cerebral artery occlusion (MCAO) vehicle, and MCAO+MIF groups. Transient MCAO (tMCAO) was performed in the MCAO groups, and the vehicle and the MIF were administered via the intracerebroventricular route. We evaluated the neurological functional scale, the rotarod test, and T2-weighted magnetic resonance imaging. The expression level of the microtubule-associated protein 2 (MAP2), Bcl2, and the brain-derived neurotrophic factor (BDNF) were further measured by Western blot assay. The Garcia test was significantly higher in the MCAO+MIF group than in the MCAO+vehicle group. The MCAO+MIF group exhibited significantly better performance on the rotarod test than the MCAO+vehicle group, which further had a significantly reduced total infarct volume on T2-weighted MRI imaging than the MCAO vehicle group. Expression levels of BDNF, and MAP2 tended to be higher in the MCAO+MIF group than in the MCAO+vehicle group. The MIF exerts a neuroprotective effect in an in vivo ischemic stroke model. The MIF facilitates neurological recovery and protects brain tissue from ischemic injury, indicating a possibility of future novel therapeutic agents for stroke patients.

Thrombin acts as inducer of proinflammatory macrophage migration inhibitory factor in astrocytes following rat spinal cord injury.

BACKGROUND: The danger-associated molecular patterns (DAMPs) are critical contributors to the progressive neuropathology and thereafter affect the functional outcomes following spinal cord injury (SCI). Up to now, the regulatory mechanisms on their inducible production from the living cells remain elusive, aside from their passive release from the necrotic cells. Thrombin is immediately activated by the damaged or stressed central nervous system (CNS), which potently mediates inflammatory astrocytic responses through proteolytic cleavage of protease-activated receptors (PARs). Therefore, SCI-activated thrombin is conceived to induce the production of DAMPs from astrocytes at lesion site. METHODS: Rat SCI model was established by the cord contusion at T8-T10. The expression of thrombin and macrophage migration inhibitory factor (MIF) was determined by ELISA and Western blot. The PAR1, PAR3, and PAR4 receptors of thrombin were examined by PCR and immunohistochemistry. Primary astrocytes were isolated and purified from the spinal cord, followed by stimulation with different concentrations of thrombin either for transcriptome sequencing or for analysis of thrombin-mediated expression of MIF and related signal pathways in the presence or absence of various inhibitors. The post-injury locomotor functions were assessed using the Basso, Beattie, and Bresnahan (BBB) locomotor scale. RESULTS: MIF protein levels were significantly elevated in parallel with those of thrombin induced by SCI. Immunostaining demonstrated that PAR1 receptor, together with MIF, was abundantly expressed in astrocytes. By transcriptome sequencing and bioinformatical analysis of thrombin-stimulated primary astrocytes, MIF was identified to be dynamically regulated by the serine protease. Investigation of the underlying mechanism using various inhibitors revealed that thrombin-activated PAR1 was responsible for the MIF production of astrocytes through modulation of JNK/NFκB pathway. Administration of PAR1 inhibitor at lesion sites following SCI significantly reduced the protein levels of MIF and ameliorated functional deficits of rat locomotion. CONCLUSION: SCI-activated thrombin is a robust inducer of MIF production from astrocytes. Exploring the roles of thrombin in promoting the production of DAMPs from astrocytes at lesion site will provide an alternative strategy for the clinical therapy of CNS inflammation.

Eugenol Inhibits the Biological Activities of an Oral Squamous Cell Carcinoma Cell Line SCC9 via Targeting MIF.

BACKGROUND: Oral squamous cell carcinoma (OSCC) is a rampant cancer type in head and neck cancers with a poor prognosis and a high recurrence rate. Eugenol shows an anticancer effect in a variety of cancers, but it has been rarely studied in oral squamous cell carcinoma (OSCC). OBJECTIVE: The purpose of this study was to explore the role of Eugenol in OSCC and the underlying mechanism. METHODS: After different concentrations of Eugenol (0, 200, 400, and 800 µM) treatment, the viability, proliferation, migration, and invasion of OSCC cell line SCC9 were measured by CCK-8, colony formation, wound-healing, and transwell assays, respectively. TUNEL staining was employed to detect apoptosis. Western blotting was used to evaluate gene expression at the protein level. Molecular docking was used to identify the target of Eugenol. RESULTS: Eugenol decreased the proliferation and reduced the abilities of invasion and migration along with the expression of matrix metalloproteinases (MMP) 2 and MMP9 in SCC9 cells. On the contrary, the ratio of apoptotic cells was increased by Eugenol. In addition, Eugenol down-regulated B cell lymphoma-2 (Bcl-2) expression, but up-regulated BCL-2 associated X (Bax), cleaved caspase 3, and cleaved poly-ADP ribose polymerase (PARP) expression. Meanwhile, Eugenol exerted its effect on SCC9 cells in a concentration-dependent manner. Eugenol could bind to macrophage migration inhibitory factor (MIF), the expression of which was down-regulated after Eugenol treatment. Besides, overexpression of MIF reversed all the effects of Eugenol on OSCC cells. CONCLUSION: In summary, Eugenol suppressed the malignant processes of OSCC cells by targeting MIF, which could guide the clinical application of Eugenol in OSCC.

MIF does only marginally enhance the pro-regenerative capacities of DFO in a mouse-osteotomy-model of compromised bone healing conditions.

The initial phase of fracture healing is crucial for the success of bone regeneration and is characterized by an inflammatory milieu and low oxygen tension (hypoxia). Negative interference with or prolongation of this fine-tuned initiation phase will ultimately lead to a delayed or incomplete healing such as non-unions which then requires an effective and gentle therapeutic intervention. Common reasons include a dysregulated immune response, immunosuppression or a failure in cellular adaptation to the inflammatory hypoxic milieu of the fracture gap and a reduction in vascularizing capacity by environmental noxious agents (e.g. rheumatoid arthritis or smoking). The hypoxia-inducible factor (HIF)-1α is responsible for the cellular adaptation to hypoxia, activating angiogenesis and supporting cell attraction and migration to the fracture gap. Here, we hypothesized that stabilizing HIF-1α could be a cost-effective and low-risk prevention strategy for fracture healing disorders. Therefore, we combined a well-known HIF-stabilizer - deferoxamine (DFO) - and a less known HIF-enhancer - macrophage migration inhibitory factor (MIF) - to synergistically induce improved fracture healing. Stabilization of HIF-1α enhanced calcification and osteogenic differentiation of MSCs in vitro. In vivo, only the application of DFO without MIF during the initial healing phase increased callus mineralization and vessel formation in a preclinical mouse-osteotomy-model modified to display a compromised healing. Although we did not find a synergistically effect of MIF when added to DFO, our findings provide additional support for a preventive strategy towards bone healing disorders in patients with a higher risk by accelerating fracture healing using DFO to stabilize HIF-1α.

Chloroquine Induces ROS-mediated Macrophage Migration Inhibitory Factor Secretion and Epithelial to Mesenchymal Transition in ER-positive Breast Cancer Cell Lines.

Breast cancer (BC) is the leading cause of cancer-related death in women in the world. Since tumor cells employ autophagy as a survival pathway, it has been proposed that autophagy inhibition could be beneficial for cancer treatment. There are several onging clinical trials where autophagy is being inhibited (using chloroquine, CQ or hydroxychloroquine, HCQ) along with chemotherapy with promising results. However, there is also in vitro evidence in which autophagy inhibition can induce epithelial to mesenchymal transition (EMT) in cancer cells, indicating that, at least in some cases, this strategy could be detrimental for cancer patients. In this study, we found that the genetic inhibition of autophagy primed cells for EMT by inducing a decrease in E-cadherin protein levels, while CQ treatment decreased E-cadherin levels, induced morphological changes related to EMT, increased EMT-related transcription factor (EMT-TF) expression and migration in estrogen receptor positive (ER +) BC cell lines. Importantly, CQ treatment increased intracellular reactive oxygen species (ROS) which induced the secretion of macrophage migration inhibitory factor (MIF), a pro-inflammatory cytokine related to malignancy. Both ROS production and MIF secretion were responsible for the mesenchymal morphology and increased migratory capacity induced by CQ. Our results indicate that CQ treatment increased malignancy by inducing ROS production, MIF secretion and EMT and suggest that autophagy inhibition in ER + BC patients might have detrimental effects. Our data indicates that a careful selection of patients should be performed in order to determine who will benefit the most from autophagy inhibition with available pharmacological agents for the treatment of breast cancer.

BEWO trophoblast cells and Toxoplasma gondii infection modulate cell death mechanisms in THP-1 monocyte cells by interference in the expression of death receptor and intracellular proteins.

Crosstalk between trophoblast and monocytes is essential for gestational success, and it can be compromised in congenital toxoplasmosis. Cell death is one of the mechanisms involved in the maintenance of pregnancy, and this study aimed to evaluate the role of trophoblast in the modulation of monocyte cell death in the presence or absence of Toxoplasma gondii infection. THP-1 cells were stimulated with supernatants of BeWo cells and then infected or not with T. gondii. The supernatants were collected and analyzed for the secretion of human Fas ligand, and cells were used to determine cell death and apoptosis, cell death receptor, and intracellular proteins expression. Cell death and apoptosis index were higher in uninfected THP-1 cells stimulated with supernatants of BeWo cells; however, apoptosis index was reduced by T. gondii infection. Macrophage migration inhibitory factor (MIF) and transforming growth factor (TGF)-ß1, secreted by BeWo cells, altered the cell death and apoptosis rates in THP-1 cells. In infected THP-1 cells, the expression of Fas/CD95 and secretion of FasL was significantly higher; however, caspase 3 and phosphorylated extracellular-signal-regulated kinase (ERK1/2) were downregulated. Results suggest that soluble factors secreted by BeWo cells induce cell death and apoptosis in THP-1 cells, and Fas/CD95 can be involved in this process. On the other hand, T. gondii interferes in the mechanism of cell death and inhibits THP-1 cell apoptosis, which can be associated with active caspase 3 and phosphorylated ERK1/2. In conclusion, our results showed that human BeWo trophoblast cells and T. gondii infection modulate cell death in human THP-1 monocyte cells.

The Novel Role of MIF in the Secretion of IL-25, IL-31, and IL-33 from PBMC of Patients with Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is an autoimmune inflammatory joint disease with complex pathogenesis associated with cytokine dysregulation. Macrophage migration inhibitory factor (MIF) plays a role in systemic inflammation and joint destruction in RA and could be associated with the secretion of other immune-modulatory cytokines such as IL-25, IL-31, and IL-33. For the above, our main aim was to evaluate the IL-25, IL-31, and IL-33 secretion from recombinant human MIF (rhMIF)-stimulated peripheral blood mononuclear cells (PBMC) of RA patients. The rhMIF and lipopolysaccharide (LPS) plus rhMIF stimuli promote the secretion of IL-25, IL-31, and IL-33 (p < 0.05) from PBMC of RA patients. The study groups, the different stimuli, and the interaction between both showed a statistically significant effect on the secretion of IL-25 (p < 0.05) and IL-31 (p < 0.01). The study of the effect of the RA patient treatments and their interaction with the effect of stimuli did not show an interaction between them. In conclusion, our study generates new evidence for the role of MIF in the secretion of IL-25, IL-31, and IL-33 and its immunomodulatory effect on RA.

Altered Differentiation of Tendon-Derived Stem Cells in Diabetic Conditions Mediated by Macrophage Migration Inhibitory Factor.

The purpose of our study was to evaluate the role of macrophage migration inhibitory factor (MIF) in the differentiation of tendon-derived stem cells (TdSCs) under hyperglycemic conditions. In the in vivo experiment, rats were classified into diabetic (DM) and non-DM groups depending on the intraperitoneal streptozotocin (STZ) or saline injection. Twelve-week after STZ injection, the supraspinatus tendon was harvested and prepared for histological evaluation and real-time reverse transcription polymerase chain reaction for osteochondrogenic (aggrecan, BMP-2, and Sox9) and tenogenic (Egr1, Mkx, scleraxis, type 1 collagen, and Tnmd) markers. For the in vitro experiment, TdSCs were isolated from healthy rat Achilles tendons. Cultured TdSCs were treated with methylglyoxal and recombinant MIF or MIF gene knockdown to determine the effect of hyperglycemic conditions and MIF on the differentiation function of TdSCs. These conditions were classified into four groups: hyperglycemic-control group, hyperglycemic-recombinant-MIF group, hyperglycemic-knockdown-MIF group, and normal-control group. The mRNA expression of osteochondrogenic and tenogenic markers was compared among the groups. In the in vivo experiment, the mRNA expression of all osteochondrogenic and tenogenic differentiation markers in the DM group was significantly higher and lower than that in the non-DM group, respectively. Similarly, in the in vitro experiments, the expression of all osteochondrogenic and tenogenic differentiation markers was significantly upregulated and downregulated, respectively, in the hyperglycemic-control group compared to that in the normal-control group. The hyperglycemic-knockdown-MIF group demonstrated significantly decreased expression of all osteochondrogenic differentiation markers and increased expression of only some tenogenic differentiation markers compared with the hyperglycemic-control group. In contrast, the hyperglycemic-recombinant-MIF group showed significantly increased expression of all osteochondrogenic differentiation markers, but no significant difference in any tenogenic marker level, compared to the hyperglycemic-control group. These results suggest that tendon homeostasis could be affected by hyperglycemic conditions, and MIF appears to alter the differentiation of TdSCs via enhancement of the osteochondrogenic differentiation in hyperglycemic conditions. These are preliminary findings, and must be confirmed in a further study.

Macrophage migration inhibitory factor of Thelazia callipaeda induces M2-like macrophage polarization through TLR4-mediated activation of the PI3K-Akt pathway.

Macrophage migration inhibitory factor (MIF), an immunoregulatory cytokine plays an important role in inflammation and the immune response, and has been described as having a potential role in immune evasion by parasites. Thelazia callipaeda, a vector-borne zoonotic eye worm with a broad host range, has been documented as an agent of ocular infection of thelaziosis. The ability of T. callipaeda to persist in an immunologically competent host has led to the suggestion that it has evolved specific measures to counter immune defenses. To date, whether the immune evasion of T. callipaeda is related to MIF and the possible related signaling pathway and molecular mechanism have remained unclear. In the present study, we examined the effect of T. callipaeda MIF (T. cp-MIF) on macrophages. We analyzed the antigenic epitopes of the candidate T. cp-MIF and found that it exhibited an ideal antigenic index. Morphology, Flow cytometry, and cytokine analysis showed that T. cp-MIF induced the dynamic polarization of THP-1 macrophages from the M1-like phenotype to the M2-like phenotype. The chemotaxis assay revealed an inhibitory effect of T. cp-MIF on THP-1 macrophages. Western blotting suggested that, compared to the control, THP-1 macrophages exposed to T. cp-MIF had higher TLR4 protein expression and the phosphatidylinositol 3'-kinase (PI3K) -Akt pathway activation. In conclusion, T. cp-MIF induces M2-like macrophage polarization through TLR4-mediated activation of the PI3K-Akt pathway, which might provide a basis for future research on how it affects the immune system of the host.

Macrophage migration inhibitory factor facilitates the therapeutic efficacy of mesenchymal stem cells derived exosomes in acute myocardial infarction through upregulating miR-133a-3p.

BACKGROUND: Exosome transplantation is a promising cell-free therapeutic approach for the treatment of ischemic heart disease. The purpose of this study was to explore whether exosomes derived from Macrophage migration inhibitory factor (MIF) engineered umbilical cord MSCs (ucMSCs) exhibit superior cardioprotective effects in a rat model of AMI and reveal the mechanisms underlying it. RESULTS: Exosomes isolated from ucMSCs (MSC-Exo), MIF engineered ucMSCs (MIF-Exo) and MIF downregulated ucMSCs (siMIF-Exo) were used to investigate cellular protective function in human umbilical vein endothelial cells (HUVECs) and H9C2 cardiomyocytes under hypoxia and serum deprivation (H/SD) and infarcted hearts in rats. Compared with MSC-Exo and siMIF-Exo, MIF-Exo significantly enhanced proliferation, migration, and angiogenesis of HUVECs and inhibited H9C2 cardiomyocyte apoptosis under H/SD in vitro. MIF-Exo also significantly inhibited cardiomyocyte apoptosis, reduced fibrotic area, and improved cardiac function as measured by echocardiography in infarcted rats in vivo. Exosomal miRNAs sequencing and qRT-PCR confirmed miRNA-133a-3p significantly increased in MIF-Exo. The biological effects of HUVECs and H9C2 cardiomyocytes were attenuated with incubation of MIF-Exo and miR-133a-3p inhibitors. These effects were accentuated with incubation of siMIF-Exo and miR-133a-3p mimics that increased the phosphorylation of AKT protein in these cells. CONCLUSION: MIF-Exo can provide cardioprotective effects by promoting angiogenesis, inhibiting apoptosis, reducing fibrosis, and preserving heart function in vitro and in vivo. The mechanism in the biological activities of MIF-Exo involves miR-133a-3p and the downstream AKT signaling pathway.

Migration Inhibitory Factor in Conditioned Medium from Human Umbilical Cord Blood-Derived Mesenchymal Stromal Cells Stimulates Hair Growth.

Conventional therapeutic applications of mesenchymal stromal cells (MSCs) focus on cell replacement and differentiation; however, increasing evidence suggests that most of their therapeutic effects are carried out by their various secretions. This study investigated the application of conditioned medium (CM) from human umbilical cord blood-derived MSCs (hUCB-MSCs) to improve hair growth and developed a method to reliably produce this optimized CM. Primed MSC-derived CM (P-CM) with combinations of TGF-ß1 and LiCl was optimized by comparing its effects on the cell viability of dermal papilla cells (DPCs). P-CM significantly increased the viability of DPCs compared to CM. The secretion of vascular endothelial growth factor (VEGF) in DPCs was regulated by the macrophage migration inhibitory factor (MIF) in the P-CM secreted by MSCs. These findings suggest that P-CM can improve the efficacy in hair growth via a paracrine mechanism and that MIF in P-CM exerts hair growth-promoting effects via a VEGF-related ß-catenin and p-GSK-3ß [SER9] signaling pathway. Furthermore, clinical trials have shown that 5% P-CM improved androgenetic alopecia through producing an increased hair density, thickness, and growth rate, suggesting that this topical agent may be a novel and effective treatment option for patients with androgenetic alopecia.

Effect of Natural Cytokine Complex on Metabolism of Smooth Muscle Cells in Myocardial Arteries under Normal Conditions and during Hemodynamic Overload.

Histoenzymological methods were employed to examine the effects of systemically administered natural cytokine complex including IL-1, IL-2, IL-6, TNFα, MIF, and TGFß on metabolism of smooth muscle cells in intramural myocardial arteries under physiological conditions and during acute hemodynamic overload of the heart. Natural cytokine complex markedly inhibited metabolism of vascular smooth muscle cells under control conditions and during acute experimental aortal stenosis. In vascular smooth muscle cells, deceleration of tricarboxylic acid cycle, redistribution of the fluxes in glycolytic cascade and its inhibition, down-regulation of oxidation of free fatty acids and their metabolites, and inhibition of the shuttle systems and biosynthetic processes were observed. Inhibition of metabolism in the vascular wall of myocardial arteries correlated with a decrease in their tone and could be partially determined by a decrease in contractile activity of smooth muscle cells. These findings do not exclude the involvement of other factors and mechanisms in down-regulation of metabolism in vascular myocytes in response to increased cytokines levels of in the blood, including their direct effect on biochemical processes in cells.

LncRNA-NEAT1 from the competing endogenous RNA network promotes cardioprotective efficacy of mesenchymal stem cell-derived exosomes induced by macrophage migration inhibitory factor via the miR-142-3p/FOXO1 signaling pathway.

AIMS: Extracellular vesicles, especially exosomes, have emerged as key mediators of intercellular communication with the potential to improve cardiac function as part of cell-based therapies. We previously demonstrated that the cardioprotective factor, macrophage migration inhibitory factor (MIF), had an optimizing effect on mesenchymal stem cells (MSCs). The aim of this study was to determine the protective function of exosomes derived from MIF-pretreated MSCs in cardiomyocytes and to explore the underlying mechanisms. METHODS AND RESULTS: Exosomes were isolated from control MSCs (exosome) and MIF-pretreated MSCs (exosomeMIF), and delivered to cardiomyocytes subjected to H2O2 in vitro. Regulatory long non-coding RNAs (lncRNAs) activated by MIF pretreatment were explored using genomics approaches. ExosomeMIF protected cardiomyocytes from H2O2-induced apoptosis. Mechanistically, we identified lncRNA-NEAT1 as a mediator of exosomeMIF by regulating the expression of miR-142-3p and activating Forkhead class O1 (FOXO1). The cardioprotective effects of exosomeMIF were consistently abrogated by depletion of lncRNA-NEAT1, by overexpression of miR-142-3p, or by FOXO1 silencing. Furthermore, exosomeMIF inhibited H2O2-induced apoptosis through modulating oxidative stress. CONCLUSIONS: Exosomes obtained from MIF-pretreated MSCs have a protective effect on cardiomyocytes. The lncRNA-NEAT1 functions as an anti-apoptotic molecule via competitive endogenous RNA activity towards miR-142-3p. LncRNA-NEAT1/miR-142-3p/FOXO1 at least partially mediates the cardioprotective roles of exosomeMIF in protecting cardiomyocytes from apoptosis.