Inhibitory Effect Of FK506 Research Articles

FK506 inhibition of gliostatin/thymidine phosphorylase production induced by tumor necrosis factor-α in rheumatoid fibroblast-like synoviocytes

Gliostatin/thymidine phosphorylase (GLS/TP) is known to have angiogenic and arthritogenic activities. The purpose of this study was to determine the inhibitory effects of FK506 (tacrolimus) on GLS production in rheumatoid arthritis (RA). We investigated the modulation of serum GLS by FK506 therapy and the effect of FK506 on the production of GLS in fibroblast-like synoviocytes (FLSs). Serum samples were collected from 11 RA patients with active disease at baseline and after 12 weeks of FK506 treatment. Serum concentrations of GLS and matrix metalloproteinase (MMP)-3 were measured by ELISA and found to be down-regulated in responders evaluated with a disease activity score. Patient FLSs were cultured and stimulated by tumor necrosis factor (TNF)-α with or without FK506. The expression levels of GLS were determined using reverse transcription-polymerase chain reaction (RT-PCR) and enzyme immunoassay and shown to be significantly increased. GLS levels in TNF-α-stimulated FLSs were reduced by FK506 treatment. Our data show a novel mechanism for the action of physiological concentrations of FK506 in RA that regulates the production of GLS in FLSs.

Use of tacrolimus, a potent antifibrotic agent, in bleomycin-induced lung fibrosis

Idiopathic pulmonary fibrosis has a poor prognosis and few efficacious treatments. The immunosuppressant cyclosporin A has been shown to inhibit tumour growth factor (TGF)-beta-induced collagen deposition in vitro, and is widely used in Japan as a potent antifibrotic agent. Tacrolimus (FK506) is another attractive immunosuppressant, which may be useful in the treatment of pulmonary fibrosis. The aim of the present study was to elucidate the antifibrotic effect of FK506. The inhibitory effect of FK506 on collagen synthesis in cultured lung fibroblastic cells, TIG-3-20, and its antifibrotic effect on bleomycin (BLM)-induced pulmonary fibrosis in mice was investigated. FK506 inhibited TGF-beta-induced collagen synthesis, and suppressed the expression of TGF-beta type I receptor (TbetaR-I) in TIG-3-20 cells. Consistent with the in vitro findings, FK506 treatment starting on day 6 attenuated BLM-induced pulmonary fibrosis, in part, via reduced TbetaR-I expression. FK506 treatment in the acute BLM injury phase unexpectedly increased pro-inflammatory cytokine levels in bronchoalveolar lavage fluid and enhanced lung injury, resulting in poor survival. In conclusion, the present results suggest that FK506 has a potent antifibrotic effect and may be useful for the treatment of pulmonary fibrosis, although its use in the acute inflammatory phase may exacerbate lung injury.

The Essential Role of MEKK3 Signaling in Angiotensin II-induced Calcineurin/Nuclear Factor of Activated T-cells Activation

Calcineurin is a serine/threonine protein phosphatase that plays a critical role in many physiologic processes, such as T-cell activation, apoptosis, skeletal myocyte differentiation, and cardiac hypertrophy. We determined that active MEKK3 was capable of activating calcineurin/nuclear factor of activated T-cells (NFAT) signaling in cardiac myocytes and reprogramming cardiac gene expression. In contrast, small interference RNA directed against MEKK3 and a dominant negative form of MEKK3 caused the reduction of NFAT activation in response to angiotensin II in cardiac myocytes. Genetic studies showed that MEKK3-deficient mouse embryo fibroblasts failed to activate calcineurin/NFAT in response to angiotensin II, a potent NFAT activator. Conversely, restoring MEKK3 to the MEKK3-deficient cells restored angiotensin II-mediated calcineurin/NFAT activation. We determined that angiotensin II induced MEKK3 phosphorylation. Thus, MEKK3 functions downstream of the AT1 receptor and is essential for calcineurin/NFAT activation. Finally, we determined that MEKK3-mediated activation of calcineurin/NFAT signaling was associated with the phosphorylation of modulatory calcineurin-interacting protein 1 at Ser(108) and Ser(112). Taken together, our studies reveal a previously unrecognized novel essential regulatory role of MEKK3 signaling in calcineurin/NFAT activation.

The role of endothelin in FK506-induced vascular reactivity changes in rat perfused kidney

Tacrolimus (FK506) is an immunosuppressant agent that is widely used in transplanted patients. The aim of this study was to investigate the role of endothelin in the acute effects of FK506 on the vascular reactivity in perfused isolated rat renal and mesenteric vasculature. Left kidney/mesentery of male Wistar rats (230–300 g) were perfused by a constant flow and perfusion pressure was recorded. The responses to noradrenaline and sodium nitroprusside were obtained both in the absence and presence of FK506 (10 − 7 M) or polyoxyethylene hydrogenated castor oil 60 (HCO-60 and solvent of the drug at equivalent concentrations). FK506 significantly increased the noradrenaline-induced vasoconstrictor responses in renal, but not in mesenteric vascular beds. Bosentan (10 − 5 M), a nonselective endothelin ET-1 receptor antagonist given by perfusion, reversed the increase in noradrenaline responses in the kidney. Sodium nitroprusside-induced vasodilator responses in both renal and mesenteric vascular beds were significantly decreased by FK506. However, in renal vasculature, there was no significant difference between the inhibitory effects of FK506 and HCO-60, although the effect of the solvent was not significantly different from that of the control. While in the mesenteric bed, the solvent significantly inhibited nitroprusside-induced vasodilation, similar to that of FK506. The effect of FK506 on vasodilation in both vascular beds was not reversed by bosentan. Our results indicated that FK506 increased the reactivity of the renal vascular bed to noradrenaline through endothelin ET-1 receptor activation. The mechanism of impaired vasodilation due to FK506 appears to be due to its solvent action and is independent of endothelin release.

Inhibitory effect of FK506 and cyclosporine A on the growth and invasion of human liver cancer cells.

The prognosis of liver transplantation for liver cancer is determined by recurrence in the liver graft. In this study, the effects of immunosuppressors, FK506 and cyclosporine A (CsA) on the migration of liver cancer cells were investigated. The effects of FK506 at concentrations of 1-100 ng/mL and CsA at 1-1000 ng/mL on the growth of poorly and well differentiated human hepatocellular carcinoma cell lines, HLE and HuH-7, respectively, were examined. After treatment of these cells with FK506 and CsA, the growth of these cells, their cytotoxicities and invasion assay on the Matrigel basement membrane invasion chamber were evaluated. In addition, the effects of FK506 and CsA on the changes in the production of a soluble intercellular adhesion molecule-1 (sICAM-1) of these cells were measured. FK506 and CsA at concentrations of 1-10 ng/mL inhibited the growth of both HLE and HuH-7 and those immunosuppressors at concentrations over 100 ng/mL exhibited cytotoxicity on these cells. FK506 at concentration of 1 ng/mL significantly inhibited the invasion of poorly differentiated HLE, but not well differentiated HuH-7, after treatment for 2-5 days in culture (p<0.05), but FK 506 at 10 ng/mL showed less inhibitory efficient. CsA at concentrations of 1-10 ng/mL, however, did not inhibit or transiently inhibited the invasion of both cell lines. The production of ICAM-1 in HLE and HuH-7 was suppressed by FK506 at concentrations of 1-10 ng/mL after treatment for 3-5 days but the effect was not significant in the initial phase at days 1-2 and the last phase at days 5-6. FK506, but not CsA, at a clinical dose of 1 ng/mL significantly inhibited the invasion of the poorly-differentiated HLE, but not HuH-7 and also inhibited the production of sICAM-1 in HLE.

Assembly of heterodimeric luciferase after de novo synthesis of subunits in rabbit reticulocyte lysate involves hsc70 and hsp40 at a post-translational stage.

Heterodimeric luciferase from Vibrio harveyi had been established as a unique model enzyme for direct measurements of the effects of molecular chaperones and folding catalysts on protein folding and subunit assembly after de novo synthesis of subunits in rabbit reticulocyte lysate. It was observed that luciferase assembly can be separated in time from synthesis of the two subunits and that under these post-translational conditions assembly was inhibited by either ATP depletion or inhibition of peptidylprolyl cis/trans isomerases, that is, by addition of cyclosporin A or FK506. Furthermore, it was observed that the inhibitory effect of FK506 on luciferase assembly can be suppressed by addition of purified cyclophilin, thereby providing the first direct evidence for the involvement of peptidylprolyl cis/trans isomerases in protein biogenesis in the eukaryotic cytosol. Here the ATP requirement in luciferase assembly has been characterized. Depletion of either Hsp90 or CCT from reticulocyte lysate did not interfere with luciferase assembly. However, addition of purified Hsc70 stimulated luciferase assembly. While addition of purified Hsp40 did not have any effect on luciferase assembly, the stimulatory effect of Hsc70 was further increased by Hsp40. Thus, after synthesis of the two subunits in reticulocyte lysate assembly of heterodimeric luciferase involves Hsc70 and its co-chaperone Hsp40. Therefore, Hsc70 aids protein biogenesis in the eukaryotic cytosol not only at the levels of nascent polypeptide chains and precursor proteins that have to be kept competent for transport into cell organelles, but also at the level of subunits that have to be kept competent for assembly.

Inhibitory effect of FK506 on the induction of NMDA receptor-dependent and -independent LTPs in developing visual cortex

Inhibitory effect of FK506 on the induction of NMDA receptor-dependent and -independent LTPs in developing visual cortex

Erythromycin inhibits transcriptional activation of NF-kappaB, but not NFAT, through calcineurin-independent signaling in T cells.

The molecular mechanism of the anti-inflammatory effect of erythromycin (EM) was investigated at the level of transcriptional regulation of cytokine gene expression in T cells. EM (>10(-6) M) significantly inhibited interleukin-8 (IL-8) expression but not IL-2 expression from T cells induced with 20 ng of phorbol 12-myristate 13-acetate (PMA) per ml plus 2 microM calcium ionophore (P-I). In electrophoretic mobility shift assays EM at 10(-7) to 10(-5) M concentrations inhibited nuclear factor kappa B (NF-kappaB) DNA-binding activities induced by P-I. Reporter gene assays also showed that EM (10(-5) M) inhibited IL-8 NF-kappaB transcription by 37%. The inhibitory effects of EM on transcriptional activation of IL-2 and DNA-binding activity of nuclear factor of activated T cells (NFAT) were not seen in T cells. On the other hand, FK506, which is also a macrolide derivative, inhibited transcriptional activation of both NF-kappaB and NFAT more strongly than EM did. The mechanism of EM inhibition of transactivation of NF-kappaB was further investigated in transiently transfected T cells that express calcineurin A and B subunits. Expression of calcineurin did not render transactivation of NF-kappaB in T cells more resistant to EM, while the inhibitory effect of FK506 on transactivation of NF-kappaB was attenuated. These findings indicate that EM is capable of inhibiting expression of the IL-8 gene in T cells through transcriptional inhibition and that this inhibition is mediated through a non-calcineurin-dependent signaling event in T lymphocytes.

Prostaglandin E2Stimulates Amyloid Precursor Protein Gene Expression: Inhibition by Immunosuppressants

Amyloid plaques that accumulate in the brains of patients with Alzheimer's disease (AD) are primarily composed of aggregates of amyloid peptides that are derived from the amyloid precursor protein (APP). Overexpression of APP in cell cultures increases the formation of amyloidogenic peptides and causes neurodegeneration and cognitive dysfunction in transgenic mice. We now report that activation of prostaglandin E2 (PGE2) receptors increases cAMP formation and stimulates overexpression of APP mRNA and holoprotein in primary cultures of cortical astrocytes. Levels of glial fibrillary acidic protein were also increased by PGE2 treatment, suggesting that these cultured astrocytes resemble reactive astrocytes found in vivo. The stimulation by PGE2 of APP synthesis was mimicked or blocked by activators or inhibitors, respectively, of protein kinase A. Actinomycin D or cycloheximide also inhibited the increase in APP holoprotein stimulated by PGE2. Treatment of astrocytes with 8-Bromo-cAMP or forskolin for 24 hr also stimulated APP overexpression in cultured astrocytes. The immunosuppressants cyclosporin A and FK-506 inhibited the increase in APP mRNA and holoprotein levels caused by PGE2 or by other treatments that elevated cellular cAMP levels; the inhibitory effect of FK-506 but not of cyclosporin A was attenuated by rapamycin. These results suggest that prostaglandins produced by brain injury or inflammation can activate APP transcription in astrocytes and that immunosuppressants may be used to prevent APP overexpression and possibly the pathophysiological processes underlying AD.

Purification and Characterization of a Novel Physiological Substrate for Calcineurin in Mammalian Cells

Although the calcium/calmodulin-regulated protein phosphatase calcineurin has been shown to play a role in a number of intracellular processes, relatively few of the downstream phosphoproteins that are dephosphorylated by this enzyme in cells have been described. Calcineurin was previously shown to play a role in amylase secretion by rat pancreatic acinar cells and to specifically dephosphorylate a 24-kDa cytosolic protein. The present study describes the purification and characterization of this novel phosphoprotein, termed CRHSP-24 (calcium-regulated heat-stable protein with a molecular mass of 24 kDa). Microgram quantities of CRHSP-24 were purified from a large-scale rat pancreas preparation in a procedure involving heat and acid precipitation, anion-exchange chromatography, preparative electrophoresis, electroelution, and two-dimensional electrophoresis. Internal amino acid sequence was obtained from two peptides following trypsin digestion and high pressure liquid chromatography. Both sequences matched with 100% identity nucleotide sequences of expressed sequence tags from human placenta and rat PC-12 cells. Two CRHSP-24 transcripts of 0.7 and 2. 9 kilobases were detected in multiple rat tissues by Northern analysis, whereas a single 24-kDa protein was observed by Western blotting. The CRHSP-24 protein is 147 amino acids in length, is composed of nearly 14% proline, and is phosphorylated entirely on serine residues. Western analysis and 32P metabolic labeling of acini revealed CRHSP-24 to be maximally phosphorylated in control cells and to undergo a rapid sustained dephosphorylation on at least 3 serine residues in response to calcium-mobilizing stimuli. Dephosphorylation of CRHSP-24 was completely inhibited by pretreatment of acini with cyclosporin A or FK506. Furthermore, the inhibitory effects of FK506 were blocked by excess rapamycin. The ubiquitous expression of CRHSP-24 in rat tissues suggests that this novel calcineurin substrate plays a common role in calcium-mediated signal transduction.

Effects of FK506 and cyclosporin A on proliferation, histamine release and phenotype of murine mast cells.

Using mouse peritoneal cavity mast cells, we investigated the effects of FK506 and cyclosporin A (CsA) on cell proliferation and histamine release induced by anti-IgE antibody, calcium ionophore (A23 187), or neuropeptide (substance P). Both FK506 and CsA inhibited cytokine-dependent mast cell proliferation in a dose-dependent manner. The inhibitory effects of these compounds on mast cell proliferation was reversible; the removal of the chemicals from the incubation medium resulted in the reinitiation of mast cell proliferation. Flow cytometric analysis suggested that the inhibitory effect of FK506 and CsA was mostly due to G1/S boundary block, although a significant number of G2-arrested cells were also observed following FK506 treatment. Both FK506- and CsA-treated mast cells showed a similar inhibition of histamine release induced by A23187. However, CsA at higher concentrations inhibited the histamine release induced by anti-IgE antibody or substance P more markedly than FK506. Cellular histamine content was decreased by CsA treatment while FK506 had no effect. The staining properties of peritoneal mast cells changed from connective tissue-type mast cell-like to mucosal mast cell-like during CsA treatment but not during FK506 treatment. Thus FK506 and CsA have different effects on mast cell proliferation as well as histamine release, that might be associated with a phenotypic change of the cells during culture.

The inhibitory effect of FK506 on cytotoxic T-lymphocyte killing

The immunosuppressant FK506 inhibits N-α- benzyloxylcarbonyl- l-lysine thiobenzyl ester (BLT) esterase release from cytotoxic T lymphocytes (CTL). In addition, serine esterase has been demonstrated to be strongly associated with CTL killing. In the present study, the effect of FK506 on the activity of CTL killing against target cells was examined. FK506 inhibited lysis of antigen (Ag)-treated CTL target cells by auto-CTL, but failed to inhibit lysis of conventional P815 target cells by CTL. Moreover, FK506 inhibited DNA fragmentation of CTL target cells lysed by auto-CTL. Killing of CTL target cells by FK506-pretreated auto-CTL was inhibited, but FK506-pretreated CTL target cells were killed by auto-CTL. Incubation of both FK506 and Ag-pretreated CTL target cells with untreated auto-CTL induced DNA fragmentation. These indicated that FK506 inhibited CTL killing by influencing effector, but not CTL target cells. These results suggest that FK506 may function by inhibiting alloreactive CTL killing in organ transplantation in addition to the interruption of the T-cell receptor signal transduction leading to cytokine production.

Inhibitory effect of FK506 on intercellular adhesion molecule-1 (ICAM-1) expression on cultured thyroid cells.

The effect of FK506, an immunosuppressive agent, on phytohemagglutinin (PHA) or interferon gamma (IFN gamma)-induced intercellular adhesion molecule-1 (ICAM-1) expression on cultured human thyroid cells from patients with Graves' disease was investigated. Primary cultured thyroid cells were incubated for three days with IFN gamma (10 to 800 U/ml) or PHA (1 to 50 micrograms/ml) in the presence of FK506. The surface expression of ICAM-1 was measured by flow cytometry. In some experiments, polyclonal anti-IFN gamma antibody was added to the culture to determine whether ICAM-1 expression was blocked. FK506 inhibited the PHA-induced ICAM-1 expression in thyroid cells, but not the induction by IFN gamma. PHA-induced ICAM-1 expression was not inhibited by the polyclonal anti-IFN gamma antibody. FK506 did not affect the proliferation of thyroid cells. This data indicates that the inhibitory effect of FK506 on ICAM-1 expression in primary cultured thyroid cells may be due to actions on infiltrating lymphocytes in the thyroid gland. Further studies are necessary to elucidate whether the inhibition of ICAM-1 by FK506 results in the suppression of autoimmune reactions in the thyroid gland.

FK506 and cyclosporin a regulate proliferation and proto-oncogene expression in HTLV-1-associated myelopathy/tropical-spastic-paraparesis-derived T cells.

Human T-cell-leukemia-virus-type-1 (HTLV-1) infection is associated with adult T-cell leukemia/lymphoma (ATL) and HTLV-1-associated myelopathy (HAM)/tropical spastic paraparesis (TSP). The T-cell-targeting immunosuppressants, FK506 and cyclosporin A (CsA), suppressed proliferation of the HAM/TSP-derived T-cell lines, H89-59, H89-79 and H109. FK506 and CsA also reduced expression of the proto-oncogenes, c-myc and c-fos, but not c-jun and interleukin-2-receptor-alpha (IL-2R alpha) gene in H109 cells. The growth-inhibitory effects of FK506 and CsA were not abrogated by interleukin 2 (IL-2). These results suggest that the inhibitory effects of FK506 and CsA are independent of IL-2, and are associated with the reduction of c-myc and c-fos gene expression.

Protective effect of FK506 on ischemia/reperfusion-induced myocardial damage in canine heart.

We investigated the cardioprotective effect of FK506, a newly developed immunosuppressive agent, on ischemia-reperfusion-induced myocardial damage and the inhibitory effect of FK506 on superoxide radical formation by neutrophils. Open-chest anesthetized dogs were divided into two groups: group 1, 2-h occlusion of the coronary artery followed by 1-h reperfusion; and group 2, 2-h occlusion followed by 1-h reperfusion with preadministration of FK506 (0.5 mg/kg). After reperfusion, heart mitochondria were prepared from the normal and reperfused areas and mitochondrial function and mitochondrial GSH (the reduced form of glutathione) and GSSG (the oxidized form of glutathione) concentrations were measured. In addition, neutrophils were collected from normal healthy dogs, and the inhibitory effect of FK506 on superoxide radical formation by neutrophils was also investigated. One-hour reperfusion after 2-h coronary occlusion induced significant mitochondrial dysfunction associated with a marked depletion of mitochondrial GSH concentration. FK506 reduced mitochondrial dysfunction, depletion of mitochondrial GSH concentration, and development of reperfusion arrhythmias. FK506 also reduced stimulant-induced superoxide radical formation by normal neutrophils dose dependently. Radical scavenging activity decreased in association with reperfusion, and FK506 reduced superoxide radical formation by neutrophils, which might contribute to lessening ischemia-reperfusion damage.

Anti-tumor-promoting action of FK506, a potent immunosuppressive agent.

The effect of FK506, a potent immunosuppressive agent, on 7,12-dimethylbenz[a]anthracene-initiated and 12-O-tetradecanoylphorbol-13- acetate (TPA)-promoted skin papilloma formation was examined in CD-1 mice. A topical application of FK506 to mouse skin 15 min before each TPA treatment resulted in a dose-related inhibition of tumor formation. FK506 (1 mumol) almost completely inhibited tumor formation. This inhibitory effect of FK506 was not due to any damage inflicted on the initiated cells but due to its anti-tumor-promoting action. A topical application of FK506 also inhibited epidermal ornithine decarboxylase induction and skin inflammation caused by TPA in a dose-related manner. Significant inhibition by FK506 of TPA-induced endogenous protein phosphorylation in intact epidermal cells was not detected. These results indicate that FK506 inhibits TPA-induced tumor promotion at a step distal to the endogenous protein phosphorylation by TPA.

O-321 - Anti-tumor-promoting action of FK506, a potent immunosuppressive agent

The effect of FK506, a potent immunosuppressive agent, on 7,12-dimethylbenz[a]anthracene-initiated and 12-O-tetradecanoylphorbol-13- acetate (TPA)-promoted skin papilloma formation was examined in CD-1 mice. A topical application of FK506 to mouse skin 15 min before each TPA treatment resulted in a dose-related inhibition of tumor formation. FK506 (1 mumol) almost completely inhibited tumor formation. This inhibitory effect of FK506 was not due to any damage inflicted on the initiated cells but due to its anti-tumor-promoting action. A topical application of FK506 also inhibited epidermal ornithine decarboxylase induction and skin inflammation caused by TPA in a dose-related manner. Significant inhibition by FK506 of TPA-induced endogenous protein phosphorylation in intact epidermal cells was not detected. These results indicate that FK506 inhibits TPA-induced tumor promotion at a step distal to the endogenous protein phosphorylation by TPA.

264 Inhibitory effect of FK-506 on the development of late asthmatic response amd bronchial hyperresponsiveness

264 Inhibitory effect of FK-506 on the development of late asthmatic response amd bronchial hyperresponsiveness

FK506

WARTY, VIJAY; DIVEN, WARREN; CADOFF, EVAN; TPDO, SATORU; STARZL, THOMAS; SANGHVI, AJIT Author Information