Effect of interferon-gamma, tumor necrosis factor, interleukin-1 and interleukin-6 on the modulation of anti-tumor responses of bone marrow derived macrophages

Microenvironmental changes in familial adenomatous polyposis during colorectal cancer carcinogenesis

Familial adenomatous polyposis (FAP) is a heritable disease that increases the risk of colorectal cancer (CRC) development because of heterozygous mutations in APC. Little is known about the microenvironment of FAP. Here, single-cell RNA sequencing was performed on matched normal tissues, adenomas, and carcinomas from four patients with FAP. We analyzed the transcriptomes of 56,225 unsorted single cells, revealing the heterogeneity of each cell type, and compared gene expression among tissues. Then we compared the gene expression with that of sporadic CRC. Furthermore, we analyzed specimens of 26 FAP patients and 40 sporadic CRC patients by immunohistochemistry. Immunosuppressiveness of myeloid cells, fibroblasts, and regulatory T cells was upregulated even in the early stages of carcinogenesis. CD8+ T cells became exhausted only in carcinoma, although the cytotoxicity of CD8+ T cells was gradually increased according to the carcinogenic step. When compared with those in the sporadic CRC microenvironment, the composition and function of each cell type in the FAP-derived CRC microenvironment had differences. Our findings indicate that an immunosuppressive microenvironment is constructed from a precancerous stage in FAP.

Histamine induces chemotaxis and phagocytosis in murine bone marrow-derived macrophages and RAW 264.7 macrophage-like cells via histamine H4-receptor

OBJECTIVE

Expression and function of histamine H4-receptor, an immunomodulatory receptor involved in inflammatory diseases, on murine macrophages, which are vital for immunity, were investigated.

MATERIALS AND METHODS

The expression pattern of histamine receptors on bone marrow-derived macrophages of BALB/c mice and on RAW 264.7 cells was studied at the mRNA level by reverse transcription polymerase chain reaction. The functional relevance of histamine receptors was investigated by analyzing histamine-induced chemotaxis and phagocytosis in the presence of histamine receptor antagonists mepyramine (histamine H1-receptor), famotidine (histamine H2-receptor), thioperamide (histamine H3/4-receptors) and JNJ7777120 (histamine H4-receptor).

RESULTS

Both bone marrow-derived macrophages and RAW 264.7 cells express mRNA for histamine H1-receptor and histamine H4-receptor. Residual amounts of histamine H2-receptor mRNA are found in bone marrow-derived macrophages only. In both cellular models, histamine induced chemotaxis and phagocytic activity, which was reduced by thioperamide as well as by JNJ 7777120, but not by mepyramine or famotidine.

CONCLUSION

In murine bone marrow-derived macrophages and RAW 264.7 macrophage-like cells histamine H4-receptor mediates chemotaxis and phagocytic activity.

Could a B-1 cell derived phagocyte "be one" of the peritoneal macrophages during LPS-driven inflammation?

The inflammatory response is driven by signals that recruit and elicit immune cells to areas of tissue damage or infection. The concept of a mononuclear phagocyte system postulates that monocytes circulating in the bloodstream are recruited to inflamed tissues where they give rise to macrophages. A recent publication demonstrated that the large increase in the macrophages observed during infection was the result of the multiplication of these cells rather than the recruitment of blood monocytes. We demonstrated previously that B-1 cells undergo differentiation to acquire a mononuclear phagocyte phenotype in vitro (B-1CDP), and we propose that B-1 cells could be an alternative origin for peritoneal macrophages. A number of recent studies that describe the phagocytic and microbicidal activity of B-1 cells in vitro and in vivo support this hypothesis. Based on these findings, we further investigated the differentiation of B-1 cells into phagocytes in vivo in response to LPS-induced inflammation. Therefore, we investigated the role of B-1 cells in the composition of the peritoneal macrophage population after LPS stimulation using osteopetrotic mice, BALB/Xid mice and the depletion of monocytes/macrophages by clodronate treatment. We show that peritoneal macrophages appear in op/op((-/-)) mice after LPS stimulation and exhibit the same Ig gene rearrangement (VH11) that is often found in B-1 cells. These results strongly suggest that op/op((-/-)) peritoneal "macrophages" are B-1CDP. Similarly, the LPS-induced increase in the macrophage population was observed even following monocyte/macrophage depletion by clodronate. After monocyte/macrophage depletion by clodronate, LPS-elicited macrophages were observed in BALB/Xid mice only following the transfer of B-1 cells. Based on these data, we confirmed that B-1 cell differentiation into phagocytes also occurs in vivo. In conclusion, the results strongly suggest that B-1 cell derived phagocytes are a component of the LPS-elicited peritoneal macrophage population.

Kinetics and dose dependence of macrophage colony-stimulating factor-induced proliferation and activation of murine mononuclear phagocytes in situ: differences between lungs, liver, and spleen

Alveolar macrophages (AM) play an important role in antimicrobial defense mechanisms of the lung. It therefore seems reasonable to use macrophage colony-stimulating factor (M-CSF) to enhance local resistance mechanisms. However, little is known about the in vivo activity of M-CSF on macrophages in various organs. We determined the effect of a single subcutaneous dose of M-CSF (10, 50, 100, and 500 ng, respectively) on the number and functional status of AM as well as of macrophages in liver and spleen of mice. Organs were investigated immunohistochemically on days 1 and 3 after injection using monoclonal antibodies specific for F4/80, Ia antigen, and MAC-1. We found a significant increase in the number of F4/80+ AM, Kupffer cells, and splenic macrophages reaching its maximum 24 h after injection of low doses (10 and 50 ng per mouse, respectively) of M-CSF and decreasing to a level seen in untreated mice at 72 h after M-CSF in liver and spleen, whereas at a dose of 50 ng per mouse the number of AM remained high. In contrast, the numbers of AM, Kupffer cells, and splenic macrophages did not increase significantly when high doses were used (500 ng). The expression of Ia antigen and MAC-1 was increased on macrophages in the spleen but not on AM or Kupffer cells. TNF-alpha was elevated in bronchoalveolar (BAL) fluid after 3 h and IL-6 at 6, 12, and 24 h after M-CSF injection in dose-dependent manner. Nitric oxide production was not increased after injection of M-CSF. Our results point to regional differences in the response of macrophages to M-CSF. These may caused by differences in the M-CSF-induced production of TNF-alpha and IL-6. These findings may be important for the therapeutic use of M-CSF in microbial infections.

Potentiation of antitumor effects of tumor necrosis factor alpha and interferon gamma by macrophage-colony-stimulating factor in a MmB16 melanoma model in mice

The efficacy of systemic infusion of recombinant human macrophage-colony-stimulating factor (M-CSF) in combination with local treatment with human recombinant tumor necrosis factor (TNF) alpha and mouse recombinant interferon (IFN) gamma was studied in vivo on a subclone of B16 melanoma (MmB16) in mice. Short-term intravenous administration of M-CSF at a dose of 10(6) units daily had no antitumor effect in vivo. Similarly, local treatment of tumor with TNF alpha (5 micrograms daily) did not produce any therapeutic effect. However, simultaneous administration of the same dose of TNF alpha with IFN gamma (1000 units daily) resulted in a synergistic effects manifested by the retardation of tumor growth. Addition of systemic infusion of M-CSF to the local therapy with TNF alpha and IFN gamma induced further augmentation of antitumor efficacy and delayed progression of MmB16 melanoma. The strengthened antitumor effect of combination therapy including M-CSF, TNF alpha and IFN gamma was most probably due to the increased release of monocytes from the bone marrow, their recruitment into the site of tumor growth and subsequent local stimulation of their antitumor activity.

Effect of TNF alpha production inhibitors BRL 61063 and pentoxifylline on the response of rats to poly I:C

BRL 61063 is a novel xanthine phosphodiesterase (PDE) type IV inhibitor with selective inhibitory activity for tumor necrosis factor (TNF) alpha production. This compound inhibits TNF alpha production by activated human blood monocytes in vitro and in animal models of endotoxemia and influenza infection. Inhibition of TNF alpha may be beneficial in many diseases; however, little is known about potential adverse effects of such inhibition on host defense. In an ex vivo study, we examined the effect of BRL 61,063 on the microbicidal and tumoricidal activity of pulmonary lavage cells during a local inflammatory response in rats challenged with Poly I:C. Pentoxifylline, a PDE inhibitor which also blocks TNF alpha production, was used for comparison. Treatment with BRL 61063 or pentoxifylline did not block the inflammatory response to Poly I:C or the activation of bronchoalveolar lavage (BAL) cells but reduced the level of tumoricidal activity attained. At the dosages used, pentoxifylline was more inhibitory than BRL 61063. Drug treatment did not prevent further stimulation of tumoricidal activity by LPS in vitro. LPS-stimulated cells from BRL 61063-treated rats reached a level of activation similar to the control group while the LPS-stimulated activity of BAL cells from pentoxifylline treated rats remained lower than control. Although pentoxifylline was more inhibitory for tumoricidal activity than BRL 61063, the latter was a more potent inhibitor of TNF alpha release as measured in vivo in LPS-challenged rats. This finding indicates that TNF alpha is not the main mediator involved in the activation of pulmonary macrophage tumoricidal function. Treatment with either BRL 61063 or pentoxifylline had little or no effect on the Poly I:C-induced candidacidal activity of BAL cells indicating that these compounds are unlikely to compromise non-specific host defense against infection.