Calcium-binding Proteins MRP14 Research Articles

Neutrophils and the calcium-binding protein MRP-14 mediate carrageenan-induced antinociception in mice.

BACKGROUND: We have previously shown that the calcium-binding protein MRP-14 secreted by neutrophils mediates the antinociceptive response in an acute inflammatory model induced by the intraperitoneal injection of glycogen in mice. AIM: In an attempt to broaden the concept that neutrophils and MRP-14 controls inflammatory pain induced by different type of irritants, in the present study, after demonstrating that carrageenan (Cg) also induces atinociception in mice, we investigated the participation of both neutrophils and MRP-14 in the phenomenon. METHODS: Male Swiss mice were injected intraperitoneally with Cg and after different time intervals, the pattern of cell migration of the peritoneal exudate and the nociceptive response of animals submitted to the writhing test were evaluated. The participation of neutrophils and of the MRP-14 on the Cg effect was evaluated by systemic inoculation of monoclonal antibodies anti-granulocyte and anti-MRP-14. RESULTS: Our results demonstrate that the acute neutrophilic peritonitis evoked by Cg induced antinociception 2, 4 and 8 h after inoculation of the irritant. Monoclonal antibodies anti-granulocyte or anti-MRP-14 reverts the antinociceptive response only 2 and 8 h after Cg injection. The antibody anti-MRP-14 partially reverts the antinociception observed after 4 h of Cg injection while the anti-granulocyte antibody enhances this effect. This effect is reverted by simultaneous treatment of the animals with both antibodies. After 4 h of Cg injection in neutrophil-depleted mice a significant expression of the calcium-binding protein MRP-14 was detected in the cytoplasm of peritoneal macrophages. This suggests that the enhancement of the effect observed after treatment with the anti-neutrophil antibody may be due to secretion of MRP-14 by macrophages. It has also been demonstrated that endogenous opioids and glucocorticoids are not involved in the antinociception observed at the 4th hour after Cg injection. CONCLUSION: These data support the hypothesis that neutrophils and the calcium-binding protein MRP-14 are participants of the endogenous control of inflammatory pain in mice despite the model of acute inflammation used.

Expression, purification, crystallization and preliminary X-ray diffraction analysis of the human calcium-binding protein MRP14 (S100A9)

MRP14 is a protein that is specifically expressed in myeloid and epithelial cells during the stages of acute or chronic inflammatory states such as rheumatoid arthritis or sarcoidosis. MRP14 has EF-hand motifs as Ca(2+)-binding sites and belongs to the S100 family of proteins. This paper deals with the sample preparation (cloning, overexpression and purification), crystallization and preliminary crystallographic analysis of recombinant human MRP14. Crystals of MRP14 were obtained by the hanging-drop vapour-diffusion method. MRP14 crystals belong to space group P2(1), with unit-cell parameters a = 57.59, b = 178.44, c = 61.23 A, beta = 113.17 degrees, and diffract to 2.1 A resolution.

Activation of macrophages/microglia with the calcium-binding proteins MRP14 and MRP8 is related to the lesional activities in the spinal cord of HTLV-I associated myelopathy

Macrophages and microglia may play an important role in the pathogenesis of chronic inflammatory process in HTLV-I associated myelopathy (HAM) and tropical spastic paraparesis (TSP). However, the etiology and cellular mechanism of chronic inflammation are poorly understood in HAM/TSP. To help to define the roles of macrophages and microglia we analyzed the various patterns of macrophage and microglia activation in the central nervous system (CNS) of HAM/TSP using several monoclonal antibodies recognizing the different states of activation. The results indicate that a large number of macrophages and microglia express both MRP14 and MRP8 in active-chronic inflammatory lesions of the patients with a short duration of illness (2.5 years). In the patient whose duration of illness was 4.5 years, perivascular and parenchymal macrophages and microglia were reactive for MRP8 but not for MRP14. In contrast, MRP14 and MRP8 were negative on the perivascular and parenchymal macrophages and microglia in inactive-chronic lesions and in controls. This study suggests that (a) activated macrophages and microglia as well as CD4+ T lymphocytes and CD8+ cytotoxic T lymphocytes are main components of the inflammatory process in the CNS in HAM/TSP, (b) activation of macrophages and microglia is related to the amount of HTLV-I proviral DNA in situ.

Antinociceptive effect of the calcium-binding protein MRP-14 and the role played by neutrophils on the control of inflammatory pain.

Macrophages secrete a variety of chemical mediators that play a central role in the pathophysiology of inflammatory pain. Therefore, the activation or deactivation of these cells in an inflammatory focus could modulate the intensity of the algogenic response. Based on these premises and on our previous demonstration that the calcium-binding protein MRP-14, highly expressed in neutrophils, deactivates activated macrophages in vitro, we decided to investigate the role of MRP-14 and of neutrophils in the control of inflammatory pain in mice. Our results show that this protein is endowed with antinociceptive activity. When tested in the writhing model it was able to inhibit pain response but did not change the behavior of the animals in the hot plate test. This observation indicates that MRP-14 down-regulates inflammatory but not central pain. Using a model of acute neutrophilic peritonitis induced by glycogen, a close correlation between neutrophil migration and antinociception was detected. Surgical adrenalectomy demonstrated that the antinociceptive response induced by glycogen was not due to endogenous liberation of glucocorticoids. The treatment of animals either with a monoclonal antibody anti-MRP-14 or a monoclonal antibody that depletes the animals of neutrophils reverts the antinociceptive response observed in the glycogen-induced peritonitis. These data define the calcium-binding protein MRP-14 as a novel mediator for the control of inflammatory pain and consequently discloses an anti-inflammatory role for the neutrophil.

Epithelioid cells from foreign-body granuloma selectively express the calcium-binding protein MRP-14, a novel down-regulatory molecule of macrophage activation.

The S-100 proteins MRP-8 and MRP-14 are expressed by cells of the myelomonocytic lineage, either alone or simultaneously during certain stages of cellular differentiation. We demonstrate that MRP-14 but not MRP-8 was detected by immunostaining in the cytoplasm of epithelioid cells on the surface of round coverslips implanted for 14 days into the subcutaneous tissue of mice. Using this experimental model, our laboratory has previously shown that epithelioid macrophages are poor phagocytic cells that release a macrophage-deactivating factor (MDF) in short-term cultures. The full chemical characterization of MDF has not been achieved so far. We provide evidence that the calcium-binding protein MRP-14 was also released by epithelioid macrophages in short-term cultures and that its neutralization from the culture medium after addition of monoclonal antibody anti-MRP-14 abolished the MDF activity of the conditioned medium. Purified or recombinant human MRP-14 but not MRP-8 inhibits the respiratory burst of BCG-activated macrophages. Recombinant mouse MRP-14 also down-regulate macrophage activation in vitro, and PMA does not revert the inhibitory effect induced by MRP-14. It is thus concluded that epithelioid cells from foreign-body granuloma express and release MRP-14 in short-term cultures and that this molecule is endowed with MDF activity.

Expression of MRP14, 27E10, interferon-alpha and leukocyte common antigen by reactive microglia in postmortem human brain tissue.

We have immunohistochemically investigated the localization of a panel of leukocyte-related molecules in postmortem human brain tissue from control subjects and patients with Alzheimer's disease (AD). Microglia constitutively express leukocyte common antigens (LCA) with CD45RB determinants. Depending on the state of activation, microglia become positive for the myeloid cell-specific calcium binding protein MRP14, LCA with CD45RO determinant, interferon-alpha, and an antigen recognized by monoclonal antibody 27E10. In AD lesions, these cells are activated in a manner consistent with a chronic inflammatory state. The results of this study have shown further parallels in protein expression between activated microglia and activated leukocytes of the myeloid lineage.