Xenopus laevis Macrophage Migration Inhibitory Factor Is Essential for Axis Formation and Neural Development

Parthanatos: Mechanisms, modulation, and therapeutic prospects in neurodegenerative disease and stroke

Parthanatos is a cell death signaling pathway that has emerged as a compelling target for pharmaceutical intervention. It plays a pivotal role in the neuron loss and neuroinflammation that occurs in Parkinson's Disease (PD), Alzheimer's Disease (AD), Huntington's Disease (HD), Amyotrophic Lateral Sclerosis (ALS), and stroke. There are currently no treatments available to humans to prevent cell death in any of these diseases. This review provides an in-depth examination of the current understanding of the Parthanatos mechanism, with a particular focus on its implications in neuroinflammation and various diseases discussed herein. Furthermore, we thoroughly review potential intervention targets within the Parthanatos pathway. We dissect recent progress in inhibitory strategies, complimented by a detailed structural analysis of key Parthanatos executioners, PARP-1, AIF, and MIF, along with an assessment of their established inhibitors. We hope to introduce a new perspective on the feasibility of targeting components within the Parthanatos pathway, emphasizing its potential to bring about transformative outcomes in therapeutic interventions. By delineating therapeutic opportunities and known targets, we seek to emphasize the imperative of blocking Parthanatos as a precursor to developing disease-modifying treatments. This comprehensive exploration aims to catalyze a paradigm shift in our understanding of potential neurodegenerative disease therapeutics, advocating for the pursuit of effective interventions centered around Parthanatos inhibition.

Polymorphisms in the hypoxia inducible factor binding site of the macrophage migration inhibitory factor gene promoter in schizophrenia

Background

Macrophage migration inhibitory factor (MIF) is a multifunctional cytokine that promotes neurogenesis and neuroprotection. MIF is predominantly expressed in astrocytes in the brain. The serum MIF level and microsatellites/single nucleotide polymorphisms (SNPs) in the MIF gene promoter region are known to be associated with schizophrenia (SCZ). Interestingly, previous studies reported that hypoxia, an environmental risk factor for SCZ, induced MIF expression through binding of the hypoxia inducible factor (HIF)-1 to the hypoxia response element (HRE) in the MIF promoter.

Methods

We investigated the involvement of MIF in SCZ while focusing on the HIF pathway. First, we conducted an association study of the SNP rs17004038 (C>A) in the HRE of the MIF promoter between 1758 patients with SCZ and 1507 controls. Next, we investigated the effect of hypoxia on MIF expression in primary cultured astrocytes derived from neonatal mice forebrain.

Results

SNP rs17004038 was significantly associated with SCZ (p = 0.0424, odds ratio = 1.445), indicating that this SNP in the HRE of the MIF promoter was a genetic risk factor for SCZ. Hypoxia induced MIF mRNA expression and MIF protein production and increased HIF-1 binding to the MIF promoter, while the activity of the MIF promoter was suppressed by mutations in the HRE and by deletion of the HRE in astrocytes.

Conclusion

These results suggest that SNP rs17004038 in the HRE of the MIF promoter was significantly associated with SCZ and may be involved in the pathophysiology of SCZ via suppression of hypoxia and HIF pathway-induced MIF expression.

Characterization and expression of macrophage migration inhibitory factor (mif) in Chinese sturgeon (Acipenser sinensis)

The Chinese sturgeon (Acipenser sinensis) is one of the critically endangered aquatic species in China. It is also among the oldest extant actinopterygian fish species. To advance the characterization of the Chinese sturgeon immune system, we identified the gene encoding the macrophage migration inhibitory factor (MIF), a multifunctional cytokine that contributes to both innate and adaptive immune responses. Molecular and phylogenic analysis indicates the Chinese sturgeon (cs) MIF share a high degree of structural conservation with other MIF sequences and is closely related to other bony fish MIF. At steady state, cs-mif gene is expressed at relatively high levels in the brain, and to a lesser but significant level in liver, spleen, kidney, gut and skin. The spatial expression patterns determined by in situ hybridization indicates a preferential distribution of cs-mif transcripts in the cerebral cortex, the gut epithelium, hematopoietic tissues of kidney, spleen and liver parenchyma, and skin epidermis. Marked increase of cs-mif gene expression was induced by lipopolysaccharide (LPS) stimulation and Aeromonas hydrophila infection in all tested tissues. Furthermore, higher cs-mif transcript levels were detected in the liver, spleen, kidney, gut and skin during stress response resulting from hyperthermia. These results are not only consistent with the expected role of cs-mif gene in innate immunity but also suggest a potential role of this gene in stress response to hyperthermia in the Chinese sturgeon.

M2-like cells from the macrophage lineage might play a central role in closure of the embryonic neural tube

Herein it is hypothesized that M2-like macrophages or pre-macrophages of fetal origin might play a central role in development and closure of the neural tube. Early in embryonic development, pre-macrophages arise from the fetal yolk sac and track through the bloodstream to reach diverse embryonic tissues, where they mature. Most of these macrophages exhibit an M2-like phenotype. The critical period for neural tube closure is contained within the period of yolk sac-derived pre-macrophage tracking and distribution, which poses a question: might these pre-macrophages or macrophages exert an influence on the closing neural tube? Evidence suggests that perturbations in macrophage polarization or M2 macrophage function might contribute to the failure of neural tube closure associated with diabetes mellitus, one carbon metabolism (including folic acid deficit), inositol, arachidonic acid, and sphingosine-1-phosphate, as well as in the teratogenicity of nitric acid, valproic acid, and fumonisin. The influence of each of these factors is interpreted in light of potential interactions with M2-like macrophages or macrophage progenitors on the developing neural tube. By placing these anti inflammatory macrophages at the center of various epigenetic, neurochemical, and signaling processes suspected to be involved in neural tube closure, potential associations are revealed between macrophages and embryonic structural developmental processes such as collagen and actin dynamics. The choice of this model is also an attempt to explain why some etiologies for failure of neural tube closure are rescued by folic acid, whereas other etiologies are rescued only by formate, inositol, or not at all.

Macrophage migration inhibitory factor is involved in inflammation response in pathogen challenged Apostichopus japonicus

Macrophage migration inhibitory factor (MIF) is a cytokine and plays critical roles in inflammatory and immune responses in vertebrates. However, its functional role in inflammation has not been well studied in invertebrates. In the present study, we cloned and characterized MIF gene from Apostichopus japonicus by RNA-seq and RACE approaches (designated as AjMIF). A 1047 bp fragment representing the full-length cDNA of AjMIF was obtained, including a 5' UTR of 100 bp, an open reading frame (ORF) of 366 bp encoding a polypeptide of 121 amino acids residues with the molecular weight of 13.43 kDa and theoretical isoelectric point of 5.63 and a 3' UTR of 580 bp. SMART analysis showed that AjMIF has conserved MIF domain (2-117aa) similar to its mammalian counterparts. The amino terminal proline residue (P²) and invariant lysine residue (K³³) which are critical active sites of tautomerase activity in mammalian MIF were also detected. Phylogenic analysis and multiple alignments have shown that AjMIF shared higher degree of structural conservation and sequence identities with other counterparts from invertebrates and vertebrates. For Vibrio splendidus challenged sea cucumber, the peak expression of AjMIF mRNAs in coelomocytes were detected at 6 h (23.5-fold) and remained at high levels until 24 h (4.01-fold), and returned to normal level at 48 h in comparison with that of the control group. Similarly, a significant increase in the relative mRNA levels of AjMIF was also found in 10 μg mL^-1 LPS-exposed primary cultured coelomocytes. Functional analysis indicated that recombinant AjMIF incubation could promote inflammatory response related genes of Ajp105, AjVEGF, AjMMP1 and AjHMGB3 expression by 1.35-fold, 1.36-fold, 1.83-fold and 1.27-fold increase, respectively, which was consistent with the findings in vertebrate MIFs. All these results collectively suggested that AjMIF had a similar function to MIFs in higher animals and might serve as a candidate cytokine in inflammatory regulation in sea cucumber.

Two macrophage migration inhibitory factors (MIFs) from the clam Ruditapes philippinarum: Molecular characterization, localization and enzymatic activities

Macrophage migration inhibitory factor (MIF) is an evolutionarily ancient cytokine-like factor and plays a critical role in both innate and adaptive immunity. In the present study, two MIFs (designed as RpMIF-1 and RpMIF-2, respectively) were identified and characterized from the clam Ruditapes philippinarum by rapid amplification of cDNA ends (RACE) approaches. The full-length cDNA of RpMIF-1 and RpMFI-2 consisted of 531 and 722 nucleotides, encoding a polypeptide of 113 and 114 amino acid residues, respectively. Multiple alignments and phylogenetic analysis revealed that both RpMIF-1 and RpMIF-2 belonged to the MIF family. The conserved catalytic-site Pro² for tautomerase activity was identified in the deduced amino acid sequences of RpMIFs. Both RpMIF-1 and RpMIF-2 transcripts were constitutively expressed in examined tissues of R. philippinarum with dominant expression in hepatopancreas, gills and hemocytes. Immunolocalization analysis showed that RpMIF-1 and RpMIF-2 proteins were expressed in examined tissues with the exception of adductor muscle and foot. After Vibrio anguillarum and Micrococcus luteus challenge, the mRNA expression of RpMIFs was significantly modulated in hemocytes, gills and hepatopancreas. Recombinant RpMIF-1 and RpMIF-2 proteins possessed significant tautomerase activity and oxidoreductase activity, indicating that these two proteins was perhaps involved in inflammatory responses. In summary, our results suggested that RpMIF-1 and RpMIF-2 played an important role in the innate immunity of R. philippinarum.

Trichomonas vaginalis Macrophage Migration Inhibitory Factor Mediates Parasite Survival during Nutrient Stress

Trichomonas vaginalis is responsible for the most prevalent non-viral sexually transmitted disease worldwide, and yet the mechanisms used by this parasite to establish and maintain infection are poorly understood. We previously identified a T. vaginalis homologue (TvMIF) of a human cytokine, human macrophage migration inhibitory factor (huMIF). TvMIF mimics huMIF’s role in increasing cell growth and inhibiting apoptosis in human host cells. To interrogate a role of TvMIF in parasite survival during infection, we asked whether overexpression of TvMIF (TvMIF-OE) confers an advantage to the parasite under nutrient stress conditions by comparing the survival of TvMIF-OE parasites to that of empty vector (EV) parasites. We found that under conditions of serum starvation, overexpression of TvMIF resulted in increased parasite survival. Serum-starved parasites secrete 2.5-fold more intrinsic TvMIF than unstarved parasites, stimulating autocrine and paracrine signaling. Similarly, we observed that addition of recombinant TvMIF increased the survival of the parasites in the absence of serum. Recombinant huMIF likewise increased the parasite survival in the absence of serum, indicating that the parasite may use this host survival factor to resist its own death. Moreover, TvMIF-OE parasites were found to undergo significantly less apoptosis and reactive oxygen species (ROS) generation under conditions of serum starvation, consistent with increased survival being the result of blocking ROS-induced apoptosis. These studies demonstrated that a parasitic MIF enhances survival under adverse conditions and defined TvMIF and huMIF as conserved survival factors that exhibit cross talk in host-pathogen interactions.

Macrophage migration inhibitory factor (MIF) is a conserved protein found in most eukaryotes which has been well characterized in mammals but poorly studied in other eukaryotes. The limited analyses of MIF proteins found in unicellular eukaryotes have focused exclusively on the effect of parasitic MIF on the mammalian host. This was the first study to assess the function of a parasite MIF in parasite biology. We demonstrate that the Trichomonas vaginalis MIF functions to suppress cell death induced by apoptosis, thereby enhancing parasite survival under adverse conditions. Our research reveals a conserved survival mechanism, shared by a parasite and its host, and indicates a role for a conserved protein in mediating cross talk in host-pathogen interactions.

The role of jab1, a putative downstream effector of the neurotrophic cytokine macrophage migration inhibitory factor (MIF) in zebrafish inner ear hair cell development

Macrophage migration inhibitory factor (MIF) is a neurotrophic cytokine essential for inner ear hair cell (HC) development and statoacoustic ganglion (SAG) neurite outgrowth, and SAG survival in mouse, chick and zebrafish. Another neurotrophic cytokine, Monocyte chemoattractant protein 1 (MCP1) is known to synergize with MIF; but MCP1 alone is insufficient to support mouse/chick SAG neurite outgrowth or neuronal survival. Because of the relatively short time over which the zebrafish inner ear develops (~30hpf), the living zebrafish embryo is an ideal system to examine mif and mcp1 cytokine pathways and interactions. We used a novel technique: direct delivery of antisense oligonucleotide morpholinos (MOs) into the embryonic zebrafish otocyst to discover downstream effectors of mif as well as to clarify the relationship between mif and mcp1 in inner ear development. MOs for mif, mcp1 and the presumptive mif and mcp1 effector, c-Jun activation domain-binding protein-1 (jab1), were injected and then electroporated into the zebrafish otocyst 25-48hours post fertilization (hpf). We found that although mif is important at early stages (before 30hpf) for auditory macular HC development, jab1 is more critical for vestibular macular HC development before 30hpf. After 30hpf, mcp1 becomes important for HC development in both maculae.

Reprint of: The non-mammalian MIF superfamily

Macrophage migration inhibitory factor (MIF) was first described as a cytokine 50 years ago, and emerged in mammals as a pleiotropic protein with pro-inflammatory, chemotactic, and growth-promoting activities. In addition, MIF has gained substantial attention as a pivotal upstream mediator of innate and adaptive immune responses and with pathologic roles in several diseases. Of less importance in mammals is an intrinsic but non-physiologic enzymatic activity that points to MIF's evolution from an ancient defense molecule. Therefore, it is not surprising that mif-like genes also have been found across a range of different organisms including bacteria, plants, protozoa, helminths, molluscs, arthropods, fish, amphibians and birds. While Genebank analysis identifying mif-like genes across species is extensive, contained herein is an overview of the non-mammalian MIF-like proteins that have been most well studied experimentally. For many of these organisms, MIF contributes to an innate defense system or plays a role in development. For parasitic organisms however, MIF appears to function as a virulence factor aiding in the establishment or persistence of infection by modulating the host immune response. Consequently, a combined targeting of both parasitic and host MIF could lead to more effective treatment strategies for parasitic diseases of socioeconomic importance.

The non-mammalian MIF superfamily

Macrophage migration inhibitory factor (MIF) was first described as a cytokine 50 years ago, and emerged in mammals as a pleiotropic protein with pro-inflammatory, chemotactic, and growth-promoting activities. In addition, MIF has gained substantial attention as a pivotal upstream mediator of innate and adaptive immune responses and with pathologic roles in several diseases. Of less importance in mammals is an intrinsic but non-physiologic enzymatic activity that points to MIF's evolution from an ancient defense molecule. Therefore, it is not surprising that mif-like genes also have been found across a range of different organisms including bacteria, plants, ‎protozoa, helminths, molluscs, arthropods, fish, amphibians and birds. While Genebank analysis identifying mif-like genes across species is extensive, contained herein is an overview of the non-mammalian MIF-like proteins that have been most well studied experimentally. For many of these organisms, MIF contributes to an innate defense system or plays a role in development. For parasitic organisms however, MIF appears to function as a virulence factor aiding in the establishment or persistence of infection by modulating the host immune response. Consequently, a combined targeting of both parasitic and host MIF could lead to more effective treatment strategies for parasitic diseases of socioeconomic importance.

Cloning, characterization, and expression of the macrophage migration inhibitory factor gene from the black tiger shrimp (Penaeus monodon)

Macrophage migration inhibitory factor (MIF) is an ancient cytokine that engages in innate immune system of vertebrates and invertebrates. In this study, the MIF gene homologue (PmMIF) was cloned from the black tiger shrimp, Penaeus monodon. The full-length cDNA sequence of PmMIF was 838 bp and contained 78 bp 5' untranslated region (UTR) and 397 bp 3' UTR, and an open reading frame (ORF) of 363 bp which coded 120 amino acids (aa). Multiple alignment analysis showed that the deduced amino acid sequence shared 98% identities with MIF from closely related species of Litopenaeus vannamei. Quantitative real-time PCR (qRT-PCR) analysis indicated that PmMIF was highly expression observed in hepatotpancreas and gills. After Vibrio harveyi challenge, PmMIF mRNA level in hepatopancreas and gills were sharply up-regulated at 6 h post-injection, and reached the maximum at 12 h. PmMIF expression level in the hepatopancreas and gills were up-regulated markedly under low (2.3%) and high (4.3%) salinity exposure, respectively. PmMIF expression level in gills increased significantly at 12 h and reached peak values (2.5- fold, 6.4-fold and 1.8-fold compared with the control) at 12 h, 48 h and 12 h after zinc, cadmium and copper exposure, respectively. In the hepatopancreas, the expression of PmMIF reached maximum levels (8.5- fold, 6.2-fold and 2.1-fold compared with the control) at 24 h, 6 h and 48 h after zinc, cadmium and copper exposure, respectively. All the results indicate that PmMIF plays an important role in responding in the innate immune system of shrimps.

Cell mediated immune response of the Mediterranean sea urchin Paracentrotus lividus after PAMPs stimulation

The Mediterranean sea urchin (Paracentrotus lividus) is of great ecological and economic importance for the European aquaculture. Yet, most of the studies regarding echinoderm's immunological defense mechanisms reported so far have used the sea urchin Strongylocentrotus purpuratus as a model, and information on the immunological defense mechanisms of Paracentrotus lividus and other sea urchins, is scarce. To remedy this gap in information, in this study, flow cytometry was used to evaluate several cellular immune mechanisms, such as phagocytosis, cell cooperation, and ROS production in P. lividus coelomocytes after PAMP stimulation. Two cell populations were described. Of the two, the amoeboid-phagocytes were responsible for the phagocytosis and ROS production. Cooperation between amoeboid-phagocytes and non-adherent cells resulted in an increased phagocytic response. Stimulation with several PAMPs modified the phagocytic activity and the production of ROS. The premise that the coelomocytes were activated by the bacterial components was confirmed by the expression levels of two cell mediated immune genes: LPS-Induced TNF-alpha Factor (LITAF) and macrophage migration inhibitory factor (MIF). These results have helped us understand the cellular immune mechanisms in P. lividus and their modulation after PAMP stimulation.

The polymorphisms of a MIF gene and their association with Vibrio resistance in the clam Meretrix meretrix

Macrophage migration inhibitory factor (MIF) is an important proinflammatory cytokine that mediates both innate and adaptive immune responses. In this study, a homolog of MIF was identified in the clam Meretrix meretrix. Ten SNPs in the DNA partial sequence of MmMIF were found to be significantly associated with Vibrio resistance (P < 0.05). Distinct expression patterns of MmMIF among different haplotypes were observed after Vibrio challenge. The results showed that haplotypes did not affect MmMIF expression in the negative control group, while the expression of MmMIF in clams with Hap1 and Hap1/Hap2 was significantly lower than that with Hap2 at 24 h in the PBS-injected group but significantly higher than that with Hap2 in the Vibrio-injected group. The results also indicate that Hap1 and Hap1/Hap2 can specifically respond to mechanical stimulation while Hap2 can specifically respond to Vibrio infection. The effect of a missense mutation was detected by site-directed mutagenesis using fusion expression of the protein, which showed that the SNP g.737 (I > V) has no effect on redox activity and tautomerase activity. These studies identified a potential marker that is enriched in Vibrio-resistant clams that can be used for the genetic breeding of Meretrix meretrix.

Macrophage Migration Inhibitory Factor Deficiency Causes Prolonged Hearing Loss After Acoustic Overstimulation

HYPOTHESIS

Macrophage migration inhibitory factor plays an important role in noise-induced hearing loss.

BACKGROUND

Macrophage migration inhibitory factor is an essential factor in axis formation and neural development. Macrophage migration inhibitory factor is expressed in the inner ear, but its function remains to be elucidated.

METHODS

Macrophage migration inhibitory factor-deficient mice (MIF(-/-) mice) were used in this study. Wild-type and MIF(-/-) mice received noise exposure composed of octave band noise. Auditory brainstem response thresholds were examined before (control) and at 0, 12, and 24 hours and 2 weeks after the intense noise exposure. Morphological findings of cochlear hair cells were investigated using scanning electron microscopy. Histopathological examination with hematoxylin and eosin staining and TUNEL assay were also performed.

RESULTS

In both the wild-type and MIF(-/-) mice, acoustic overstimulation induced significant hearing loss compared with the control level. Two weeks after the intense noise exposure, the MIF(-/-) mice had an increased hearing threshold compared with the wild-type mice. Scanning electron microscopy demonstrated that the outer hair cells in the MIF(-/-) mice were affected 2 weeks after noise exposure compared with the wild-type mice. TUNEL-positive cells were identified in the organ of Corti of the MIF(-/-) mice.

CONCLUSION

The MIF(-/-) mice had prolonged hearing loss and significant loss of cochlear hair cells after intense noise exposure. Macrophage migration inhibitory factor may play an important role in recovery from acoustic trauma. Management of macrophage migration inhibitory factor may be a novel therapeutic option for noise-induced hearing loss.

Expression of macrophage migration inhibitory factor in the mouse neocortex and posterior piriform cortices during postnatal development

Macrophage migration inhibitory factor (MIF) functions as a pleiotropic protein, participating in a vast array of cellular and biological processes. Abnormal expression of MIF has been implicated in many neurological diseases, including Parkinson's disease, epilepsy, Alzheimer's Disease, stroke, and neuropathic pain. However, the expression patterns of mif transcript and MIF protein from the early postnatal period through adulthood in the mouse brain are still poorly understood. We therefore investigated the temporal and spatial expression of MIF in the mouse neocortex during postnatal development in detail and partially in posterior piriform cortices (pPC). As determined by quantitative real-time PCR (qPCR), mif transcript gradually increased during development, with the highest level noted at postnatal day 30 (P30) followed by a sharp decline at P75. In contrast, Western blotting results showed that MIF increased constantly from P7 to P75. The highest level of MIF was at P75, while the lowest level of MIF was at P7. Immunofluorescence histochemistry revealed that MIF-immunoreactive (ir) cells were within the entire depth of the developed neocortex, and MIF was heterogeneously distributed among cortical cells, especially at P7, P14, P30, and P75; MIF was abundant in the pyramidal layer within pPC. Double immunostaining showed that all the mature neurons were MIF-ir and all the intensely stained MIF-ir cells were parvalbumin positive (Pv +) at adult. Moreover, it was demonstrated that MIF protein localized in the perikaryon, processes, presynaptic structures, and the nucleus in neurons. Taken together, the developmentally regulated expression and the subcellular localization of MIF should form a platform for an analysis of MIF neurodevelopmental biology and MIF-related nerve diseases.

Expression and localization of Rdd proteins in Xenopus embryo

The previous study has shown that repeated D domain-like (Rdd) proteins, a group of novel secretory proteins consisting of repeated domains of a cysteine-rich sequence, are involved in the process of blood vessel formation in Xenopus embryo. We performed further experiments to examine the localization of Rdd proteins in embryogenesis. Detection of tagged Rdd proteins expressed in blastomeres showed that Rdd proteins formed a high molecular weight complex and existed in the extracellular space. A rabbit antibody against the Rdd synthetic peptide identified a single band of 28 kD in embryonic tissue extract. By whole-mount immunostaining analysis, signal was detected in the regions of inter-somites, vitelline veins, and branchial arches at the tailbud stage. Staining of Rdd was remarkably reduced in the embryos injected with vascular endothelial growth factor Morpholino. We suggest that Rdd proteins interact with a molecule(s) associated with vascular precursor cells.

Macrophage migration inhibitory factor promotes proliferation and neuronal differentiation of neural stem/precursor cells through Wnt/β-catenin signal pathway

Macrophage migration inhibitory factor (MIF) is a highly conserved and evolutionarily ancient mediator with pleiotropic effects. Recent studies demonstrated that the receptors of MIF, including CD44, CXCR2, CXCR4 and CD74, are expressed in the neural stem/progenitor cells (NSPCs). The potential regulatory effect of MIF on NSPCs proliferation and neuronal differentiation, however, is largely unknown. Here, we investigated the effect of MIF on NSPC proliferation and neuronal differentiation, and further examined the signal pathway by which MIF transduced these signal effects in mouse NSPCs in vitro. The results showed that both Ki67-positive cells and neurosphere volumes were increased in a dose-dependent manner following MIF treatment. Furthermore, the expression of nuclear β-catenin was significantly stronger in MIF-stimulated groups than that in control groups. Conversely, administration of IWR-1, the inhibitor of Wnt/β-catenin pathway, significantly inhibited the proliferative effect of MIF on NSPCs. Immunostaining and Western blot further indicated that doublecortin (DCX) and Tuj 1, two neuronal markers, were evidently increased with MIF stimulation during NSPC differentiation, and there were more Tuj1-positive cells migrated out from neurospheres in MIF-stimulated groups than those in control groups. During NSPC differentiation, MIF increased the activity of β-galactosidase that responds to Wnt/β-catenin signaling. Wnt1 and β-catenin proteins were also up-regulated with MIF stimulation. Moreover, the expression of DCX and Tuj 1 was inhibited significantly by IWR-1. Taken together, the present study indicated that MIF enhances NSPC proliferation and promotes the neuronal differentiation, by activating Wnt/β-catenin signal pathway. The interaction between MIF and Wnt/β-catenin signal pathway may play an important role in modulating NSPC renewal and fate during brain development.

Macrophage migration inhibitory factor acts as a neurotrophin in the developing inner ear

This study is the first to demonstrate that macrophage migration inhibitory factor (MIF), an immune system 'inflammatory' cytokine that is released by the developing otocyst, plays a role in regulating early innervation of the mouse and chick inner ear. We demonstrate that MIF is a major bioactive component of the previously uncharacterized otocyst-derived factor, which directs initial neurite outgrowth from the statoacoustic ganglion (SAG) to the developing inner ear. Recombinant MIF acts as a neurotrophin in promoting both SAG directional neurite outgrowth and neuronal survival and is expressed in both the developing and mature inner ear of chick and mouse. A MIF receptor, CD74, is found on both embryonic SAG neurons and adult mouse spiral ganglion neurons. Mif knockout mice are hearing impaired and demonstrate altered innervation to the organ of Corti, as well as fewer sensory hair cells. Furthermore, mouse embryonic stem cells become neuron-like when exposed to picomolar levels of MIF, suggesting the general importance of this cytokine in neural development.

Characterization of molecular determinants of the conformational stability of macrophage migration inhibitory factor: leucine 46 hydrophobic pocket

Macrophage Migration Inhibitory Factor (MIF) is a key mediator of inflammatory responses and innate immunity and has been implicated in the pathogenesis of several inflammatory and autoimmune diseases. The oligomerization of MIF, more specifically trimer formation, is essential for its keto-enol tautomerase activity and probably mediates several of its interactions and biological activities, including its binding to its receptor CD74 and activation of certain signaling pathways. Therefore, understanding the molecular factors governing the oligomerization of MIF and the role of quaternary structure in modulating its structural stability and multifunctional properties is crucial for understanding the function of MIF in health and disease. Herein, we describe highly conserved intersubunit interactions involving the hydrophobic packing of the side chain of Leu46 onto the β-strand β3 of one monomer within a hydrophobic pocket from the adjacent monomer constituted by residues Arg11, Val14, Phe18, Leu19, Val39, His40, Val41, Val42, and Pro43. To elucidate the structural significance of these intersubunit interactions and their relative contribution to MIF’s trimerization, structural stability and catalytic activity, we generated three point mutations where Leu46 was replaced by glycine (L46G), alanine (L46A) and phenylalanine (L46F), and their structural properties, stability, oligomerization state, and catalytic activity were characterized using a battery of biophysical methods and X-ray crystallography. Our findings provide new insights into the role of the Leu46 hydrophobic pocket in stabilizing the conformational state of MIF in solution. Disrupting the Leu46 hydrophobic interaction perturbs the secondary and tertiary structure of the protein but has no effect on its oligomerization state.

Dermacentor variabilis: characterization and modeling of macrophage migration inhibitory factor with phylogenetic comparisons to other ticks, insects and parasitic nematodes

We have identified and characterized the full length cDNA sequence of macrophage migration inhibitory factor (MIF) from the American dog tick, Dermacentor variabilis. The nucleotide and putative amino acid sequences from this study shared a high level of sequence conservation with other tick MIFs. The bioinformatics analysis showed across species conservation of the MIF amino acid sequence in ticks, insects and nematodes. The multiple sequence alignment identified Pro 1, 3, 55; Thr 7, 112; Asn 8, 72; Ile 64, 96; Gly 65, 110, Ser 63 and Leu 87 amino acids to be highly conserved among the sequences selected for this study. Tick MIF does not have the oxidoreductase domain as found in MIFs from other animals suggesting that tick MIF is not capable of performing as an oxidoreductase. The phylogenetic analysis revealed that tick MIFs share a closer evolutionary proximity to parasitic nematode MIFs than to insect MIFs.

The cytokine macrophage migration inhibitory factor (MIF) acts as a neurotrophin in the developing inner ear of the zebrafish, Danio rerio

Macrophage migration inhibitory factor (MIF) plays versatile roles in the immune system. MIF is also widely expressed during embryonic development, particularly in the nervous system, although its roles in neural development are only beginning to be understood. Evidence from frogs, mice and zebrafish suggests that MIF has a major role as a neurotrophin in the early development of sensory systems, including the auditory system. Here we show that the zebrafish mif pathway is required for both sensory hair cell (HC) and sensory neuronal cell survival in the ear, for HC differentiation, semicircular canal formation, statoacoustic ganglion (SAG) development, and lateral line HC differentiation. This is consistent with our findings that MIF is expressed in the developing mammalian and avian auditory systems and promotes mouse and chick SAG neurite outgrowth and neuronal survival, demonstrating key instructional roles for MIF in vertebrate otic development.

Cytokine components and mucosal immunity in the oviduct of Xenopus laevis (amphibia, pipidae)

Most studies on the mucosal immunity in female reproductive tissues have been performed in mammals. In all species, apart from their reproductive strategies, immunity in the genital mucosa is required to defend the host against luminal pathogens. In this study we investigated the role of the innate immunity of the oviductal mucosa of Xenopus laevis, an amphibian characterized by external fertilization. In particular we examined the expression and localization of Interleukin-1β (IL1B), Macrophage migration inhibitory factor (MIF) and Interleukin-1 receptor type 1 (IL1R1) in different oviductal portions including an upper glandular region, an intermediate and a lower aglandular region (the ovisac). Tissues were examined by immunohistochemistry and western blot using polyclonal antibodies against human molecules. IL1B, MIF and IL1R1 were all shown in the three oviductal regions examined, albeit with a general increase towards the external environment. A substantial difference among the cytokine components was also observed mainly in the epithelium of the glandular and intermediate regions. Specifically, all three molecules were expressed by the luminal ciliated cells while only IL1R1 was present in the unciliated cells at the bottom of the epithelial ingrowths. The expression of IL1R1 in these cells appeared as a continuous layer separating the epithelium from the underlying tissues. While supporting the role of the innate immune system for host's defense against pathogens, the peculiar distribution of the cytokine components in the oviduct of X. laevis suggests novel immunologic strategies useful to assure gland secretion essential for egg formation and fertilization.

The genus Xenopus as a multispecies model for evolutionary and comparative immunobiology of the 21st century

The Xenopus model for immunological research offers a collection of invaluable research tools including MHC-defined clones, inbred strains, cell lines, and monoclonal antibodies. Further, the annotated full genome sequence of Xenopus tropicalis and its remarkable conservation of gene organization with mammals, as well as ongoing genome mapping and mutagenesis studies in X. tropicalis, add a new dimension to the study of immunity. In this paper, we review uses of this amphibian model to study: the development of the immune system; vascular and lymphatic regeneration; immune tolerance; tumor immunity; immune responses to important emerging infectious diseases; and the evolution of classical and non-classical MHC class I genes. We also discuss the rich potential of the species with different degrees of polypoidy resulting from whole genome-wide duplication of the Xenopodinae subfamily as a model to study regulation at the genome level.

A macrophage migration inhibitory factor like oxidoreductase from pearl oyster Pinctada fucata involved in innate immune responses

Macrophage migration inhibitory factor (MIF) is an important cytokine and plays a crucial role as a pivotal regulator of innate immunity. In this study, a MIF cDNA was identified and characterized from the pearl oyster Pinctada fucata (designated as PoMIF). The full-length of PoMIF was 1544 bp and consisted of a 5'-untranslated region (UTR) of 45 bp, a 3'-UTR of 1139 bp with a polyadenylation signal (AATAAA) at 12 nucleotides upstream of the poly (A) tail. The open reading frame (ORF) of PoMIF was 360 bp which encoded a polypeptide of 120 amino acids with an estimated molecular mass of 13.3 kDa and a predicted pI of 6.1. SMART analysis showed that PoMIF contained the catalytic-sites P² and K³³ for tautomerase activity, a motif C⁵⁷GSV⁶⁰ for oxidoreductase activity and a MIF family signature D⁵⁵PCGSVEVYSIGALG⁶⁹. Homology analysis revealed that the PoMIF shared 40.3-65.5% similarity and 26.9-45.0% identity to other known MIF sequences. PoMIF mRNA was constitutively expressed in seven selected tissues of healthy pearl oysters, with the highest expression level in digestive gland. Eight hours after P. fucata was injected with Vibrio alginolyticus, the expression of PoMIF mRNA was significantly up-regulated in digestive gland, gills, hemocytes and intestine. The cDNA fragment encoding mature protein of PoMIF was subcloned to expression vector pRSET and transformed into Escherichia coli BL21 (DE3). The recombinant PoMIF (rPoMIF) was expressed and purified under optimized conditions. Function analysis showed that rPoMIF had oxidoreductase activity and could utilize dithiothreitol (DTT) as reductant to reduce insulin.

Direct delivery of MIF morpholinos into the zebrafish otocyst by injection and electroporation affects inner ear development

In recent years, electroporation has become a popular technique for in vivo transfection of DNA, RNA, and morpholinos into various tissues, including the eye, brain, and somites of zebrafish. The advantage of electroporation over other methods of genetic manipulation is that specific tissues can be targeted, both spatially and temporally, for the introduction of macromolecules by the application of electrical current. Here we describe the use of electroporation for transfecting mif and mif-like morpholinos into the tissues of the developing inner ear of the zebrafish. In past studies, mif morpholino injected into embryos at the 1- to 8-cell stage resulted in widespread morphological changes in the nervous system and eye, as well as the ear. By targeting the tissues of the inner ear at later stages in development, we can determine the primary effects of MIF in the developing inner ear, as opposed to secondary effects that may result from the influence of other tissues. By using phalloidin and acetylated tubulin staining to study the morphology of neurons, neuronal processes, and hair cells associated with the posterior macula, we were able to assess the efficacy of electroporation as a method for targeted transfection in the zebrafish inner ear. The otic vesicles of 24hpf embryos were injected with morpholinos and electroporated and were then compared to embryos that had received no treatment or had been only injected or electroporated. Embryos that were injected and electroporated showed a decrease in hair cell numbers, decreased innervation by the statoacoustic ganglion (SAG) and fewer SAG neurons compared with control groups. Our results showed that direct delivery of morpholinos into otocysts at later stages avoids the non-specific nervous system and neural crest effects of morpholinos delivered at the 1-8 cell stage. It also allows examination of effects that are directed to the inner ear and not secondary effects on the ear from primary effects on the brain, neural crest or periotic mesenchyme.

A macrophage migration inhibitory factor like gene from scallop Chlamys farreri: Involvement in immune response and wound healing

Macrophage migration inhibitory factor (MIF) is an evolutionarily ancient and highly conserved cytokine with multiple functions. In the present study, a MIF-like gene was cloned from Zhikong scallop Chlamys farreri (designated as CfMIF) based on expressed sequence tag (EST) analysis and rapid amplification of cDNA ends (RACE) approach. The full-length cDNA of CfMIF was of 2296bp, consisting of a 5' untranslated region (UTR) of 60bp, a 3' UTR of 1903bp with a poly(A) tail and an open reading frame (ORF) of 333bp encoded 111 amino acid residues with a calculated molecular mass of 12.6kDa and a theoretical isoelectric point of 5.63. The deduced amino acid sequence of CfMIF shared 27-50.5% similarity with those of other known MIFs. A conserved MIF domain was identified in the deduced amino acid sequence of CfMIF, and conserved proline(2) and lysine(33) were also found to be present in CfMIF. Phylogenetic analysis revealed that CfMIF is one of MIF members. The tissue distribution and temporal expression of CfMIF in hemocytes of scallop after lipopolysaccharide (LPS), peptidoglycan (PGN) and β-glucan stimulation were detected by real-time RT-PCR. CfMIF gene was ubiquitously expressed in six selected tissues of healthy scallops, with the higher expression levels in hepatopancreas, mantle and gill. In comparison with the control group, the expression of CfMIF mRNA in hemocytes was up-regulated significantly at 6h, 24h and 48h after LPS treatment, and at all time points after PGN and glucan treatment. The cDNA fragment encoding mature peptide of CfMIF was recombined and expressed in Escherichia coli BL21 (DE3) pLysS. The recombinant protein of CfMIF (rCfMIF) promoted sheep fibroblast migration into scraped spaces in vitro. These results generated from the present study encourage us to suggest that CfMIF was a novel member of MIF family, and it was involved in immune response and wound healing by promoting fibroblast migration.

Molecular and structural characterisation of a macrophage migration inhibitory factor from sea bass (Dicentrarchus labrax L.)

The macrophage migration inhibitory factor (MIF) is a cytokine produced in numerous cell types, mainly T lymphocytes and macrophages, in response to inflammatory stimuli. In this paper we report the identification of a cDNA encoding a MIF molecule from sea bass (Dicentrarchus labrax L.), its expression analysis and its 3D structure obtained by template-based modelling. The sea bass MIF cDNA consists of 609bp that translates in one reading frame to give the entire molecule containing 115 amino acids. The sequence contains three cysteine residues in conserved positions compared to human MIF and most Teleost fishes, with the exception of zebrafish and carp. The Cys(57)-Ala(58)-Leu(59)-Cys(60) motif, present inside the stretch important for JAB1-interaction and mediator of the thiol-protein oxidoreductase activity of MIF, is conserved in sea bass, together with the Pro(2) residue that is crucial for the tautomerase catalytic activity. Real-time PCR analyses revealed that MIF is constitutively expressed in all selected tissues and organs, with the highest mRNA level observed in thymus. MIF expression was induced after 4h in vitro stimulation of head kidney leukocytes with LPS and decreased after 24h. The predicted 3D model of sea bass MIF has been used to verify the presence of structural requirements for its known biological activities.

A role for NRAGE in NF-kappaB activation through the non-canonical BMP pathway

Background

Previous studies have linked neurotrophin receptor-interacting MAGE protein to the bone morphogenic protein signaling pathway and its effect on p38 mediated apoptosis of neural progenitor cells via the XIAP-Tak1-Tab1 complex. Its effect on NF-κB has yet to be explored.

Results

Herein we report that NRAGE, via the same XIAP-Tak1-Tab1 complex, is required for the phosphorylation of IKK -α/β and subsequent transcriptional activation of the p65 subunit of NF-κB. Ablation of endogenous NRAGE by siRNA inhibited NF-κB pathway activation, while ablation of Tak1 and Tab1 by morpholino inhibited overexpression of NRAGE from activating NF-κB. Finally, cytokine profiling of an NRAGE over-expressing stable line revealed the expression of macrophage migration inhibitory factor.

Conclusion

Modulation of NRAGE expression revealed novel roles in regulating NF-κB activity in the non-canonical bone morphogenic protein signaling pathway. The expression of macrophage migration inhibitory factor by bone morphogenic protein -4 reveals novel crosstalk between an immune cytokine and a developmental pathway.

A student team in a University of Michigan biomedical engineering design course constructs a microfluidic bioreactor for studies of zebrafish development

The zebrafish is a valuable model for teaching developmental, molecular, and cell biology; aquatic sciences; comparative anatomy; physiology; and genetics. Here we demonstrate that zebrafish provide an excellent model system to teach engineering principles. A seven-member undergraduate team in a biomedical engineering class designed, built, and tested a zebrafish microfluidic bioreactor applying microfluidics, an emerging engineering technology, to study zebrafish development. During the semester, students learned engineering and biology experimental design, chip microfabrication, mathematical modeling, zebrafish husbandry, principles of developmental biology, fluid dynamics, microscopy, and basic molecular biology theory and techniques. The team worked to maximize each person's contribution and presented weekly written and oral reports. Two postdoctoral fellows, a graduate student, and three faculty instructors coordinated and directed the team in an optimal blending of engineering, molecular, and developmental biology skill sets. The students presented two posters, including one at the Zebrafish meetings in Madison, Wisconsin (June 2008).

Molecular cloning and characterization of macrophage migration inhibitory factor from small abalone Haliotis diversicolor supertexta

The macrophage migration inhibitory factor (mif) cDNA and its genome were cloned from small abalone Haliotis diversicolor supertexta. Small abalone mif (samif) was originally identified from an expressed sequence tag (EST) fragment from a normalized cDNA library. It's 5' untranslated region (UTR) was obtained by 5' rapid amplification of cDNA end (RACE) techniques and its genomic DNA was cloned by PCR. The full-length cDNA of samif was of 535 bp, consisting of a 5'-terminal UTR of 49 bp, an open reading frame of 384 bp and a 3'-terminal UTR of 102 bp. The deduced protein was composed of 128 amino acids, with an estimated molecular mass of 14.0 kDa and a predicted pI of 6.90. The full-length samif genomic DNA comprises 3238 bp, containing three exons and two introns. Real time quantitative PCR analysis revealed that samif gene is constitutively expressed in 6 selected tissues, and its expression level in hepatopancreas is higher than that in the other tissues (p < 0.01). Samif expression level in the hepatopancreas at 24 and 48 h after Vibrio parahaemolyticus injection was upregulated significantly (p < 0.01), but there was no significant change after exposure to tributyltin (TBT) (p > 0.05).

Structures of Leishmania major orthologues of macrophage migration inhibitory factor

Leishmania major, an intracellular parasitic protozoon that infects, differentiates and replicates within macrophages, expresses two closely related MIF-like proteins. To ascertain the roles and potential differences of these two Leishmania proteins, recombinant L. major MIF1 and MIF2 have been produced and the structures resolved by X-ray crystallography. Each has a trimeric ring architecture similar to mammalian MIF, but with some structurally distinct features. LmjMIF1, but not LmjMIF2, has tautomerase activity. LmjMIF2 is found in all life cycle stages whereas LmjMIF1 is found exclusively in amastigotes, the intracellular stage responsible for mammalian disease. The findings are consistent with parasite MIFs modulating or circumventing the host macrophage response, thereby promoting parasite survival, but suggest the LmjMIFs have potentially different biological roles. Analysis of the Leishmania braziliensis genome showed that this species lacks both MIF genes. Thus MIF is not a virulence factor in all species of Leishmania.

Cardioinductive network guiding stem cell differentiation revealed by proteomic cartography of tumor necrosis factor alpha-primed endodermal secretome

In the developing embryo, instructive guidance from the ventral endoderm secures cardiac program induction within the anterolateral mesoderm. Endoderm-guided cardiogenesis, however, has yet to be resolved at the proteome level. Here, through cardiopoietic priming of the endoderm with the reprogramming cytokine tumor necrosis factor alpha (TNFalpha), candidate effectors of embryonic stem cell cardiac differentiation were delineated by comparative proteomics. Differential two-dimensional gel electrophoretic mapping revealed that more than 75% of protein species increased >1.5-fold in the TNFalpha-primed versus unprimed endodermal secretome. Protein spot identification by linear ion trap quadrupole (LTQ) tandem mass spectrometry (MS/MS) and validation by shotgun LTQ-Fourier transform MS/MS following multidimensional chromatography mapped 99 unique proteins from 153 spot assignments. A definitive set of 48 secretome proteins was deduced by iterative bioinformatic screening using algorithms for detection of canonical and noncanonical indices of secretion. Protein-protein interaction analysis, in conjunction with respective expression level changes, revealed a nonstochastic TNFalpha-centric secretome network with a scale-free hierarchical architecture. Cardiovascular development was the primary developmental function of the resolved TNFalpha-anchored network. Functional cooperativity of the derived cardioinductive network was validated through direct application of the TNFalpha-primed secretome on embryonic stem cells, potentiating cardiac commitment and sarcomerogenesis. Conversely, inhibition of primary network hubs negated the procardiogenic effects of TNFalpha priming. Thus, proteomic cartography establishes a systems biology framework for the endodermal secretome network guiding stem cell cardiopoiesis.

Topology independent protein structural alignment

BACKGROUND

Identifying structurally similar proteins with different chain topologies can aid studies in homology modeling, protein folding, protein design, and protein evolution. These include circular permuted protein structures, and the more general cases of non-cyclic permutations between similar structures, which are related by non-topological rearrangement beyond circular permutation. We present a method based on an approximation algorithm that finds sequence-order independent structural alignments that are close to optimal. We formulate the structural alignment problem as a special case of the maximum-weight independent set problem, and solve this computationally intensive problem approximately by iteratively solving relaxations of a corresponding integer programming problem. The resulting structural alignment is sequence order independent. Our method is also insensitive to insertions, deletions, and gaps.

RESULTS

Using a novel similarity score and a statistical model for significance p-value, we are able to discover previously unknown circular permuted proteins between nucleoplasmin-core protein and auxin binding protein, between aspartate rasemase and 3-dehydrogenate dehydralase, as well as between migration inhibition factor and arginine repressor which involves an additional strand-swapping. We also report the finding of non-cyclic permuted protein structures existing in nature between AML1/core binding factor and ribofalvin synthase. Our method can be used for large scale alignment of protein structures regardless of the topology.

CONCLUSION

The approximation algorithm introduced in this work can find good solutions for the problem of protein structure alignment. Furthermore, this algorithm can detect topological differences between two spatially similar protein structures. The alignment between MIF and the arginine repressor demonstrates our algorithm's ability to detect structural similarities even when spatial rearrangement of structural units has occurred. The effectiveness of our method is also demonstrated by the discovery of previously unknown circular permutations. In addition, we report in this study the finding of a naturally occurring non-cyclic permuted protein between AML1/Core Binding Factor chain F and riboflavin synthase chain A.

New insights on macrophage migration inhibitory factor: Based on molecular and functional analysis of its homologue of Chinese amphioxus

Macrophage migration inhibitory factor (MIF) is an intricate cytokine. Many questions about it are not fully resolved. In order to identify the role of MIF in Chinese amphioxus, its genomic organization, transcription pattern and enzymatic activity were studied. It's found that MIF has multi-copy gene number in the Chinese amphioxus genome and special transcription pattern in reproductive organs. Interestingly, the recombinant Bbt-MIF has tantomerase and redox activity, but fails to utilize GSH to reduce insulin instead of DTT, strikingly different from MIF in mammalian. All these results indicate that MIF gene must have undergone important changes in structure and function during the transition of invertebrate/vertebrate and might exert important role in this primitive species, which may be quite different from those found in vertebrate.

Expression of macrophage migration inhibitory factor in rat skin during embryonic development

We have previously shown that human epidermal keratinocytes express macrophage migration inhibitory factor (MIF) mRNA, and immunohistochemical studies showed that MIF is expressed in human epidermis. To explore the possible pathophysiological roles of MIF in skin during rat fetal development, we examined the expression patterns of MIF during rat epidermal development using Northern blot analysis and in situ hybridization. Expression of MIF mRNA was first detected by in situ hybridization in the developing epidermis and hair germ cells from embryonic day (ED) 16. From ED 19, moderate levels of MIF expression were detected in the epidermis and epithelial sheath cells of growing hair follicles. In postnatal rat skin, higher MIF expression was detected in the epidermis and hair follicles on postnatal day 3. These observations were also confirmed by Northern blot analysis. Immunohistochemical analysis with an anti-MIF antibody showed a similar distribution to that of the mRNA. Our results suggest that MIF is associated with epidermal and hair follicle development.