Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.3.1 (alkaline phosphatase)
 47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A sensitive cell surface ELISA is described to detect interleukin-4 (IL-4)-induced major histocompatibility complex class II expression on murine B cells. The ELISA is performed on B cells cultured for 16 h in the presence of purified IL-4 or T cell-derived supernatants. A sandwich technique employing a biotin-conjugated monoclonal anti-I-E antibody followed by avidin-conjugated alkaline phosphatase is used to detect enhanced I-E MHC antigen expression on the B cells. Detection of I-E induced by both purified IL-4 and a T cell-derived supernatant was highly reproducible and sensitive using this method. Other lymphokines were found to be negative for the induction of I-E. The assay is easily performed and many sample supernatants can be rapidly screened for IL-4 activity. In addition, a general method for the removal of endogenous inhibitors of lymphokines from complex supernatants is described.
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PMID:A cell surface ELISA to detect interleukin-4-induced class II MHC expression on murine B cells. 311 27

Bone remodelling is regulated at the local level by an incompletely elucidated cytokine network. In the present study we have determined the effect of interleukin-4 (IL-4), a cytokine produced by T lymphocytes and other cells, on the activity of murine osteoblasts. IL-4 (0.1-10 ng/ml) did not influence the proliferation rate of the osteoblast-like cell line MC3T3, but inhibited the expression of alkaline phosphatase. In long-term cultures supplemented with ascorbic acid and glycerophosphate such an effect was accompanied by a retardation of matrix mineralization. IL-4 also stimulated M-CSF expression by MC3T3 cells, both at the RNA and bioactivity levels. However, no stimulation of IL-1, IL-6, GM-CSF or PGE2 production was observed. An IL-4-induced inhibition of alkaline phosphatase expression and retardation of mineralization was also found in cultures of primary osteoblast-like cells isolated from neonatal mice calvariae. These results suggest that IL-4, probably released by cells within the bone marrow, may locally influence the activity of bone-forming cells.
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PMID:Interleukin-4 as a bone regulatory factor: effects on murine osteoblast-like cells. 754 94

Interleukin-4 (IL-4) potently inhibits bone resorption by preventing the differentiation of osteoclast precursors to osteoclasts. To elucidate the role of IL-4 in bone formation, we studied the effects of human IL-4 on human osteoblast-like cells obtained from trabecular bone, which showed increased osteocalcin production in response to 1,25-(OH)2D3 in more than 10 passages. IL-4 stimulated the proliferation of osteoblast-like cells in a concentration-dependent manner, showing the minimal and maximal stimulatory effects at 10 pg/ml and 100-1000 pg/ml, respectively. IL-4 also stimulated the expression of alkaline phosphatase mRNA (1.7-fold) and the enzyme activity to the same extent at 10-100 pg/ml. Furthermore, IL-4 stimulated collagen type I mRNA expression in human osteoblast-like cells. The cytokine did not affect osteocalcin production in a short culture period (3 days). These in vitro findings suggest that IL-4, a bone-resorption-inhibitory cytokine produced by activated T cells in bone marrow, may exert an anabolic effect on osteoblast-like cells in trabecular bone through a paracrine mechanism.
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PMID:Stimulation of interleukin-4 of cell proliferation and mRNA expression of alkaline phosphatase and collagen type I in human osteoblast-like cells of trabecular bone. 784 48

Interleukin-4 (IL-4) modulates the activity of a variety of lymphoid, hemopoietic and mesenchymal cells, but little is known about its influence on bone cells. We have studied the effects of IL-4 on the human osteoblast-like cell line MG63. IL-4 (0.1-50 ng/ml) inhibited cell proliferation. The effect did not depend on cell density, but it was more marked in serum-free cultures than in the presence of serum. IL-4 also induced a dose-dependent increase in the expression of alkaline phosphatase stimulated by 1,25-dihydroxyvitamin D3, a marker of differentiated osteoblast activity. However, IL-4 did not modify the secretion of interleukin-6 or tumor necrosis factor. These results suggest that interleukin-4 may play a role as a modulator of osteoblast activity.
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PMID:Effects of interleukin-4 on human osteoblast-like cells. 832 20

Three clonally related T-cell lymphoma lines (PB-1, 2A, and 2B) were examined for expression of IL-2, IL-4, and their receptors. All three lines were derived from a single patient who had an atypical, progressive T-cell lymphoproliferative disorder involving primarily skin (Davis, T.H. et al. 1992, N. Engl. J. Med. 326:1115). The PB-1 cell line was obtained from a relatively early, clinically indolent stage of the cutaneous lymphoma, whereas the 2A and 2B lines were established from a late, aggressive stage of the lymphoma. Reverse-transcriptase PCR performed with primer pairs specific for IL-2 and IL-4 showed that no mRNA coding for these cytokines was present in any of the lines with the exception of IL-4 mRNA in the 2A line. No IL-4 protein, however, was found in any of the cell lines including 2A by immunocytochemical staining with anti-IL-4 mAb. Accordingly, no bioactive IL-4 was present in the supernatants of these lines. In contrast, all three T-cell lymphoma lines contained mRNA for IL-2R alpha, IL-2R beta, IL-4R and common gamma chain. Immunocytochemical analysis revealed that only the PB-1 line stained strongly with mAbs specific for IL-2R alpha, IL-2R beta, and IL-4R whereas the 2A and 2B lines showed only limited staining with these mAbs. In contrast to expression of IL-2R alpha and IL-4R primarily on the cell surface, IL-2R beta was localized mainly in the cell cytoplasm. Testing supernatants of the cell lines by ELISA for the presence of soluble alpha chain of the IL-2R (sIL-2R) has shown that only PB-1 secreted a large amount of sIL-2R, whereas the 2A and 2B lines secreted lesser amounts. Furthermore, the PB-1 cells expressed a relatively large number of IL-4R as determined by IL-4 binding studies using an IL-4-alkaline phosphatase fusion protein. The remaining two lines displayed only limited binding of IL-4. Addition of IL-2 and/or IL-4 to the culture medium did not modulate growth of PB-1 and the other two lines. These findings may indicate that at least some types of T-cell lymphoma evolve from cells which lose the capacity to synthesize T-cell autocrine growth factors such as IL-2 and IL-4, and show progressive loss of receptors for these cytokines.
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PMID:Analysis of IL-2, IL-4 and their receptors in clonally-related cell lines derived from a patient with a progressive cutaneous T-cell lymphoproliferative disorder. 902 95

Estrogen deficiency contributes to an increase in bone resorption and bone formation characterized by a high rate of bone turnover. Interleukin-4 (IL-4) is a rapid and potent inhibitor of bone resorption. We examined the short term in vivo effects of recombinant murine IL-4 (rmIL-4) on bone remodeling in normal and ovariectomized mice. Eight-week-old mice were randomized into the following five groups: (1) sham-operated mice (sham); (2) sham-operated mice infused with rmIL-4; (3) ovariectomized mice (ovx); (4) ovx infused with rmIL-4; and (5) ovx replaced by 10 or 20 microg of 17beta-estradiol (E2) for 14 or 28 days after ovariectomy, respectively. rmIL-4 at a dose of 5 microg/day was infused into ovx and sham for 3 days prior to sacrifice. Analyses were performed 14 and 28 days after operation. An increase in serum alkaline phosphatase and urinary deoxypyridinoline levels induced by ovariectomy was inhibited by the 3-day infusion of rmIL-4. In ovx, serum and urinary IL-6 levels were also increased significantly 14 days after ovariectomy, which were restored by E2 but not by rmIL-4. Histomorphometrical analysis of trabecular bone revealed that the 3-day infusion of rmIL-4 inhibited the high rate of bone turnover induced by ovariectomy, such as an increase in the osteoclastic surface (Oc.S/BS), number of osteoclasts per mm bone surface (N.Oc/BS), mineralized surface per mm bone surface (MS/BS), and bone mineral apposition rate (MAR). A significant decrease in the bone volume (BV/TV) observed in ovx was not modulated by a 3-day infusion of rmIL-4 prior to sacrifice. In sham, rmIL-4 also caused a significant decrease in the Oc.S/BS, N.Oc/BS, MS/BS, and MAR, but the BV/TV was not modulated by rmIL-4. We conclude that short term infusion of rmIL-4 in vivo rapidly inhibits not only bone resorption but also its formation in both sham-operated and ovariectomized growing mice, resulting in a low rate of bone turnover without modulating bone volume.
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PMID:Short-term treatment of recombinant murine interleukin-4 rapidly inhibits bone formation in normal and ovariectomized mice. 955 36

The enzyme-linked immunospot (ELISPOT) assay is an efficient technique for the enumeration of single cells secreting antibodies and cytokines. For simultaneous differentiation of individual cells producing interleukin-2 (IL-2) and/or interleukin-4 (IL-4) at a single cell level, a dual color ELISPOT assay has been developed. In the present system, the red spots corresponding to IL-2-secreting cells (T helper type 1, Th1 cells) were developed with a horseradish peroxidase and the amino ethyl carbazole (AEC)/H2O2. The light blue spots corresponding to IL-4-secreting cells (T helper type 2, Th2 cells) were developed with an alkaline phosphatase and the Vector blue. The mixed colored (indigo) spots corresponding to both kinds of cytokine-secreting cells (T helper type 0, Th0 cells) were developed with both substrates. With this system, we could detect the IL-2- and/or IL-4-secreting cells simultaneously in crude spleen cell preparation or purified CD4 fraction. This procedure provides a useful tool for quantitatively analyzing micro-levels of dynamic immune responses.
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PMID:Development of a dual color enzyme-linked immunospot assay for simultaneous detection of murine T helper type 1- and T helper type 2-cells. 971 57

Human monocytes (Mo) in culture can be differentiated into macrophages (M phi), dendritic cells (DC) and osteoclasts. In addition, we have established a Mo-derived in vitro granuloma model which here was compared with ex-vivo isolated foreign body granuloma cells. In these models overlapping phenotypes developed between monocyte-derived dendritic cells (MoDC), osteoclasts, M phi, and osteoblasts. In Mo cultures granulomas were induced by immobilized particulate material. AP activity (osteoblast marker) was found to be co-expressed with cytoplasmic tartrate resistant acid phosphatase (TRAP) as a marker of osteoclasts. While proliferating, the number of AP+ cells decreased, being replaced by cells co-expressing the osteoclast markers vitronectin receptor (VNR) and TRAP. Coexpression of the Mo/M phi marker CD68 with AP or VNR confirmed the monocytic origin of the cells. When Mo were treated with interleukin-4 (IL-4), the number of AP+ cells markedly increased and remained stably expressed over 12 days. In explants from ex vivo granulomas obtained from endoprosthetic revisions the major cell type was the AP+ cell co-expressing CD68. The bone-specific alkaline phosphatase (BAP) as a marker of osteoblasts was detected by FACS analysis in the ex vivo granuloma cells. By RT-PCR the mRNA for osteocalcin, which is a highly specific marker for osteoblasts, was detected. From our results we conclude an ontogenetic relationship between macrophages, DC and osteoclasts. Furthermore, the data suggest a transdifferentiation between Mo and osteoblasts.
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PMID:Alkaline phosphatase expression during monocyte differentiation. Overlapping markers as a link between monocytic cells, dendritic cells, osteoclasts and osteoblasts. 1087 91

Interleukin-4 (IL-4) inhibits the spontaneous and stimulated bone resorption resulting from the inhibition of osteoclast formation, as well as osteoclastic activity. Since IL-13 shares some biological properties with IL-4, it was recently reported that IL-13 inhibits bone resorption. The present study was designed to determine the effects of murine IL-4 (IL-4) and murine IL-13 (IL-13) on the murine osteoblastic cell line MC3T3-E1. IL-4 and IL-13 stimulated 3H-thymidine incorporation in the MC3T3-E1 cells and its proliferation in dose dependent manners. A spontaneous increase in alkaline phosphatase (ALP) activity in the cells after plating was inhibited by IL-4 or IL-13, and both cytokines blunted an increase in ALP activity by human parathyroid hormone (PTH) (1-34). PTH-stimulated cyclic AMP (cAMP) production was inhibited by pretreatment with IL-4 and IL-13 for 48 hr in dose dependent manners. Pretreatment with IL-4 and IL-13 for 48 hr caused a decrease in PTH-induced cAMP production at any stimulatory concentration. However, the effective dose (ED50) was unchanged by the pretreatment with these cytokines. Pretreatment with IL-4 and IL-13 did not modulate cAMP generation by forskolin. In contrast, cAMP generation by PGE2 is greater in the cells treated with the cytokines compared to those without the cytokines. These results indicate that IL-4 and IL-13 act on MC3T3-E1 cells in the same manner, stimulating cell proliferation, but inhibiting cell differentiation. The inhibition of osteoblast differentiation by IL-4 and IL-13 may be associated with a decrease in PTH actions on osteoblasts.
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PMID:Interleukin (IL)-4 and IL-13 inhibit the differentiation of murine osteoblastic MC3T3-E1 cells. 1103 73

Interleukin-13 (IL-13) inhibits cell proliferation and stimulates interleukin-6 (IL-6) formation in isolated human osteoblasts (hOBs). Because the related cytokine, interleukin-4 (IL-4), is known to exert effects similar to IL-13 in other tissues, and because IL-4 has been implicated as a regulator of bone metabolism, we compared the effects of IL-13 and IL-4 on cell proliferation, IL-6 synthesis, the expression of osteoblastic phenotypic markers in hOB cultures. Also, the receptor proteins mediating these effects in hOBs have been partly characterized. IL-4 and IL-13 dose-dependently inhibited [(3)H]-thymidine incorporation into the DNA of human osteoblasts and stimulated secretion of IL-6 into culture supernatants. IL-13 and IL-4 also increased the mRNA levels of IL-6, as measured by RNAse protection assay. Furthermore, IL-13 and IL-4 dose-dependently enhanced alkaline phosphatase (ALP) activity, but did not affect osteocalcin or collagen type I synthesis. IL-4 was tenfold more potent than IL-13 in inducing both ALP activity and IL-6 secretion, whereas the cytokines were equipotent as inhibitors of cell proliferation. The expression of mRNA for receptor subunits previously implicated in IL-4 and IL-13 signaling was investigated by reverse transcriptase-polymerase chain reaction. IL-13R, IL-13Ralpha, and IL-4Ralpha mRNA were repeatedly detected in hOBs, whereas mRNA for IL-2Rgamma(C) was not detected. Receptor-blocking antibodies to IL-4Ralpha inhibited the induction of IL-6 formation by both IL-4 and IL-13, indicating that both cytokines utilize this receptor subunit in signaling. However, the antibodies did not affect the IL-4/-13-induced inhibition of [(3)H]-thymidine incorporation or the stimulation of alkaline phosphatase (ALP), suggesting that IL-4Ralpha does not mediate these effects of IL-4/-13 in hOBs. We conclude that the cytokines IL-13 and IL-4, through sharing of receptor components, induce similar effects on hOBs, causing inhibition of cell proliferation, stimulation of IL-6, and enhanced ALP activity.
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PMID:Interleukin (IL)-13 and IL-4 inhibit proliferation and stimulate IL-6 formation in human osteoblasts: evidence for involvement of receptor subunits IL-13R, IL-13Ralpha, and IL-4Ralpha. 1124 56


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