Jun Nishihira

Macrophage migration inhibitory factor up-regulates expression of matrix metalloproteinases in synovial fibroblasts of rheumatoid arthritis.

Neutral matrix metalloproteinases (MMPs) are responsible for the pathological features of rheumatoid arthritis (RA) such as degradation of cartilage. We herein show the up-regulation of MMP-1 (interstitial collagenase) and MMP-3 (stromelysin) mRNAs of cultured synovial fibroblasts retrieved from rheumatoid arthritis (RA) patients in response to macrophage migration inhibitory factor (MIF). The elevation of MMP-1 and MMP-3 mRNA was dose-dependent and started at 6 h post-stimulation by MIF, reached the maximum level at 24 h, and was sustained at least up to 36 h. Interleukin (IL)-1β mRNA was also up-regulated by MIF. These events were preceded by up-regulation of c-jun and c-fos mRNA. Tissue inhibitor of metalloproteinase (TIMP)-1, a common inhibitor of these proteases, was slightly up-regulated by MIF. Similarly, mRNA up-regulation of MMP-1 and MMP-3 was observed in the synovial fibroblasts of patients with osteoarthritis. However, their expression levels were much lower than those of RA synovial fibroblasts. The mRNA up-regulation by MIF was inhibited by the tyrosine kinase inhibitors genestein and herbimycin A, as well as the protein kinase C inhibitors staurosporine and H-7. On the other hand, the inhibition was not seen after the addition of the cyclic AMP-dependent kinase inhibitor, H-8. The mRNA up-regulation of MMPs was also inhibited by curcumin, an inhibitor of transcription factor AP-1, whereas interleukin-1 receptor antagonist, an IL-1 receptor antagonist, failed to inhibit the mRNA up-regulation. Considering these results, it is suggested that 1) MIF plays an important role in the tissue destruction of rheumatoid joints via induction of the proteinases, and 2) MIF up-regulates MMP-1 and MMP-3 via tyrosine kinase-, protein kinase C-, and AP-1- dependent pathways, bypassing IL-1β signal transduction.

Macrophage Migration Inhibitory Factor (MIF): Its Essential Role in the Immune System and Cell Growth

Macrophage migration inhibitory factor (MIF) functions as a pleiotropic protein, participating in inflammatory and immune responses. MIF was originally discovered as a lymphokine involved in delayed hypersensitivity and various macrophage functions, including phagocytosis, spreading, and tumoricidal activity. Recently, MIF was reevaluated as a proinflammatory cytokine and pituitary-derived hormone potentiating endotoxemia. This protein is ubiquitously expressed in various organs, such as the brain and kidney. Among cytokines, MIF is unique in terms of its abundant expression and storage within the cytoplasm and, further, for its counteraction against glucocorticoids. MIF has unexpectedly been found to convert D-dopachrome, an enantiomer of naturally occurring L-dopachrome, to 5,6-dihydroxyindole. However, its physiologic significance remains to be elucidated. It was demonstrated that anti-MIF antibodies effectively suppress tumor growth and tumor-associated angiogenesis, suggesting that MIF is involved not only in inflammatory and immune responses but also in tumor cell growth. At present, MIF cannot be clearly categorized as either a cytokine, hormone, or enzyme. This review presents the latest findings on the role of MIF in the immune system and in cell growth, with regard to tumorigenesis and wound repair, and discusses its potential functions in various pathophysiologic states.

Crystal structure of the macrophage migration inhibitory factor from rat liver

The tertiary structure of the macrophage migration inhibitory factor (MIF) from rat liver (12,300 Mr) is presented at 2.2 Å resolution. Each monomer consists of two β/α/β motifs aligned in quasi two-fold symmetry, comprising a domain consisting of a four-stranded mixed β-sheet and two antiparallel α-helices. The protein exists as a trimer in the crystal. An extra β-strand that is almost perpendicular to the other β-strands joins to the β-sheet of the neighbouring monomer in the trimer. Unexpected similarities were detected between MIF and two kinds of isomerase.

Involvement of macrophage migration inhibitory factor (MIF) in the mechanism of tumor cell growth.

BackgroundMacrophage migration inhibitory factor (MIF) was recently rediscovered as a cytokine, pituitary hormone, and glucocorticoid-induced immunomodulator. MIF is constitutively expressed in various cells and enhances production of inflammatory cytokines such as tumor necrosis factor-α, interleukin-1, and interferon γ. Recently, it was reported that MIF mRNA was overexpressed in prostatic tumors, which suggests that MIF is a protein involved in tumor cell growth beyond inflammatory and immune responses.Materials and MethodsWe examined the expression of MIF in the murine colon carcinoma cell line colon 26 by Western and Northern blot analyses and immunohistochemistry. Next, we investigated the effects of transforming growth factor (TGF) β, basic fibroblast growth factor (b-FGF), and platelet-derived growth factor (PDGF) on the expression of MIF mRNA. Furthermore, we examined whether MIF is involved in tumor cell proliferation, using an MIF anti-sense plasmid transfection technique.ResultsWe demonstrated that MIF protein and its mRNA were highly expressed in colon 26 cells, using Western and Northern blot analyses, respectively. By immunohistochemical analysis, we found that MIF was localized largely in the cytoplasm of the tumor cells. In response to TGF-β, b-FGF, and PDGF, MIF mRNA expression was significantly up-regulated. Following this, we transfected the cells with an anti-sense MIF plasmid, which revealed that this treatment induced significant suppression of cell proliferation.ConclusionAlthough MIF plays multifunctional roles in a broad spectrum of pathophysiological states, little has been done to investigate the role of this protein in association with tumor growth. The current results suggest the possibility that MIF induces tumor cell growth in concert with other growth factors, which encouraged us to investigate a novel approach for tumor therapy using an anti-MIF antibody and an MIF anti-sense plasmid transfection technique.

Macrophage Migration Inhibitory Factor (MIF)

Abstract: Macrophage migration inhibitory factor (MIF) functions as a pluripotent cytokine involved in broad‐spectrum pathophysiological events in association with inflammation and immune responses. Several reports, including ours, have suggested that MIF is also involved in tumorigenesis; however, its precise role has not been fully investigated. We examined the effectiveness of anti‐MIF antibodies on tumor growth and tumor‐associated angiogenesis using murine colon cancer cell line, colon 26. We observed a significant inhibition of growth of tumors embedded on the back of BALB/c mice by treatment with anti‐MIF antibodies. Next, we implanted a Millipore chamber filled with colon cancer cells in the subcutaneous fascia of the flanks of mice and then treated them with anti‐MIF antibodies. We found that angiogenesis was markedly suppressed within the region of the subcutaneous fascia that was in contact with the chamber. To further assess the role of MIF in tumorigenesis, we established MIF transgenic mice, which demonstrated that tumor growth and the associated angiogenesis were significantly enhanced in comparison with control mice.

Identification of macrophage migration inhibitory factor (MIF) in human skin and its immunohistochemical localization

The presence and tissue localization of macrophage migration inhibitory factor (MIF) in human skin were examined. Reverse transcription‐polymerase chain reaction analysis revealed that MIF mRNA was expressed in both surgically obtained normal human epidermis and primary cultured human keratinocytes. The expression of MIF was further confirmed by Western blot analysis, which demonstrated a single band at about 12.5 kDa using a polyclonal antibody against human recombinant MIF. Immunohistochemical studies showed that MIF existed in human epidermis, especially in the basal layer. The pathophysiological role of MIF in human skin remains undefined; however, the present results indicate that MIF may play an important role in immunity, inflammation and cellular differentiation of epidermal cells.

Macrophage migration inhibitory factor induces phagocytosis of foreign particles by macrophages in autocrine and paracrine fashion

Exposure to foreign particles sometimes causes inflammatory reactions through production of cytokines and chemoattractants by phagocytic cells. In this study, we focused on macrophage migration inhibitory factor (MIF) to evaluate its pathophysiological role in the phagocytic process. Immunohistochemical analysis of human pseudosynovial tissues retrieved at revision of total hip arthroplasty showed that infiltrating mononuclear and multinuclear cells were positively stained by both an anti‐CD68 antibody and anti‐human MIF antibody. For in vitro study, MIF was released from murine macrophage‐like cells (RAW 264.7) in response to phagocytosis of fluorescent‐latex beads in a particle dose‐dependent manner. Northern blot analysis showed marked elevation of the MIF mRNA level in the phagocytic macrophage‐like cells. Moreover, pretreatment of RAW 264.7 cells with rat recombinant MIF increased the extent of phagocytosis by 1·6‐fold compared with the control. Taken together, these results suggest that MIF plays an important role by activating macrophages in autocrine and paracrine fashion to phagocytose foreign particles.

Expression of Macrophage Migration Inhibitory Factor in Human Breast Cancer: Association with Nodal Spread

Macrophage migration inhibitory factor (MIF) is known to exert pleiotropic functions including inhibition of macrophage migration, anchoring, and counteraction of the anti‐inflammatory and immunosuppressive activity of glucocorticoids. Ninety‐three primary breast cancer tissues and 64 sera of primary breast cancer patients were analyzed for the expression of MIF. The clinico‐pathological significance of MIF expression was evaluated. It was found that MIF was frequently over‐expressed in primary breast cancer tissues. RT‐PCR and western blotting analysis confirmed that wild‐type MIF is expressed, and immunohistochemical analysis showed that MIF expression was localized at tumor cells as well as stromal cells, including tumor‐associated macrophages. Intra‐tumoral MIF protein concentrations detected by enzyme‐linked immunosorbent assay (ELISA) varied with a median value of 1821 ng/mg protein (range: 8–8126 ng/mg protein), and correlated inversely with nodal involvement (P=0.039). No significant correlation was observed with other clinico‐pathological factors including tumor size, menopausal status and hormone receptors. The circulating level of MIF protein ranged up to 105.7 ng/ml (median: 17.3 ng/ml), and it was also found to correlate inversely with the number of involved nodes (P=0.02). A comparative study with other soluble inflammatory mediators showed that intratumoral levels of MIF were significantly associated with those of interleukin‐1β, suggesting that interactions between tumor cells and tumor‐associated macrophages play an important role in the up‐regulation of MIF. The multifunctional inflammatory/immune mediator MIF was frequently expressed in primary breast cancer, and its expression level was inversely associated with nodal spread. Thus, MIF seems to play a role in tumor‐stroma interactions of primary breast cancers, particularly those with a phenotype of node‐negative or minimal nodal spread.

Identification and immunohistochemical localization of macrophage migration inhibitory factor in human cornea

We identified macrophage migration inhibitory factor (MIF) mRNA expression in human cornea, and demonstrated its immunohistological localization. Reverse transcription‐polymerase chain reaction analysis revealed that MIF mRNA was expressed in both the corneal epithelial and endothelial cells. Immunohistochemical study using the polyclonal antibody prepared from immunizing a rabbit with human recombinant MIF showed that MIF was present in the basal cells of corneal epithelium and endothelial cells. The fact that MIF exists in those cells of the cornea indicates that MIF may play an important role in corneal cell immunity and cellular differentiation.

Enhancement of macrophage migration inhibitory factor (MIF) expression in injured epidermis and cultured fibroblasts

After the cDNA of human macrophage migration inhibitory factor (MIF) was cloned in 1989, this protein has been re-evaluated as a pro-inflammatory cytokine, pituitary hormone and glucocorticoid-induced immunoregulatory protein. We previously reported the expression of MIF in the basal cell layers of the epidermis, but its pathophysiological function in the skin has not been well understood. In this study, we examined the expression of MIF during the wound healing of rat skin injured by excision. Reverse transcription-polymerase chain reaction in combination with Southern blot analysis revealed that the increase of MIF mRNA expression was biphasic. The maximum peaks were observed at 3 and 24 h after the injury. Similarly, maximal increases of the serum MIF level were observed at 3 and 24 h after the injury. Immunohistochemical analysis at 12 h after injury demonstrated enhanced expression of MIF protein in the whole epidermal lesion of the wound tissue. By the Boyden chamber assay, we demonstrated that MIF had a chemotactic effect on freshly prepared keratinocytes from rat skin. Additionally, cultured fibroblasts from the skin wound lesion secreted a higher amount of MIF in response to lipopolysaccharide compared to those of the normal skin. Furthermore, administration of anti-MIF antibodies induced a delay of wound healing in vivo. Taken together, these results suggest that MIF contributes to the wound healing process of skin tissue.