Kazuya Zeki

Interleukin-4 as a potent inhibitor of bone resorption

A possible role of interleukin-4 (IL-4) in the regulation of bone turnover was assessed by employing a 45Ca prelabeled-fetal mouse long bone culture system. IL-4 inhibited the bone resorption stimulated by parathyroid hormone (PTH), PTH related protein (PTHrP), 1 alpha, 25, dihydroxy-vitamin D3 [1 alpha, 25 (OH)2 D3], interleukin-1 alpha and - 1 beta (IL-1 alpha, IL-1 beta) and prostaglandin E2 (PGE2). Anti-IL-4 on monoclonal antibody abolished the inhibitory effect of IL-4 on the bone resorption. These results suggest that IL-4 may play an important role on the inhibitory regulation of bone resorption.

Sensitivity Difference to the Suppressive Effect of Prostaglandin E2 Among Mouse Strains: A Possible Mechanism to Polarize Th2 Type Response in BALB/c Mice

PGE2 has been shown to play a prominent role in regulating Th1 and Th2 type responses. We studied the role of PGE2 in IFN-γ production by Staphylococcus aureus Cowan I-stimulated spleen cells from several mouse strains such as BALB/c, C3H/HeN, and C57BL/6. When spleen cells were pretreated with indomethacin (cyclooxygenase (COX)-1 and COX-2 inhibitor) or NS-398 (COX-2-specific inhibitor), S. aureus Cowan I -induced IFN-γ production was increased more markedly in spleen cells from BALB/c mice than from C3H/HeN and C57BL/6 mouse. However, PGE2 production was not significantly different among spleen cells from three mouse strains. When various concentrations of PGE2 were exogeneously added to spleen cells, PGE2 showed a stronger suppressive effect on IFN-γ production in spleen cells from BALB/c mice than from other strains of mice. This suppressive effect of PGE2 in BALB/c mice mainly depended on IL-12p70 production by APCs. More PGE2 binding sites were found in BALB/c spleen cells than in C3H/HeN spleen cells, indicating that the sensitivity difference to the suppressive effect of PGE2 was due to the difference of the number of PGE2 receptors. The administration of NS-398 into BALB/c mice enhanced Ag-specific IFN-γ production, but not IL-4 production. This effect is the same as IL-12 administration in vivo. From these results, we propose that the modulation of PGE2 is important for Th1 activation via IFN-γ and IL-12p70 production in vitro and in vivo and that PGE2 is one of the pivotal factors in the Th2-dominant immune response in BALB/c mice.

Prostaglandin E2 Up-Regulates Macrophage-Derived Chemokine Production but Suppresses IFN-Inducible Protein-10 Production by APC

PGE2 has been known to suppress Th1 responses. We studied the role of PGE2 in two representative chemokines, macrophage-derived chemokine (MDC) and IFN-inducible protein-10, production by LPS- or CD40-stimulated spleen cells. The production of MDC, one of the ligands for CCR4 preferentially expressed on Th2, was enhanced in nonstimulated, LPS-, CD40-, or CD3-stimulated spleen cells by the pretreatment with PGE2, while the production of IFN-inducible protein-10, a representative ligand for CXC chemokine receptor 3 expressed on Th1, was suppressed. MDC production was also enhanced by IL-4, IL-5, and intracellular cAMP-elevating agents such as dibutyryl cAMP and 3-isobutyl-1-methylxanthine, and the effect of IL-4, IL-5, and PGE2 was additive. However, the pretreatment with IL-6, IL-10, or TGF-β, or the neutralization of IFN-γ or IL-12 had no effect on MDC production. B cells, macrophages, and dendritic cells were main producers of MDC, while T cells produced only a small amount of MDC. MDC production by B cells was equally stimulated by LPS and anti-CD40 Ab, while that by macrophages and dendritic cells was more markedly stimulated by anti-CD40 Ab, and PGE2 further enhanced MDC production by these stimulated cells. These results indicate that PGE2 regulates Th1/Th2-related chemokine production by B cells, macrophages, and dendritic cells, and that this is a new function of PGE2 for the regulation of Th2 immune responses at the induction and activation stages.

Parathyroid Hormone-Related Peptide-(1–34) [PTHrP- (1–34)] Induces Vasopressin Release from the Rat Supraoptic Nucleus in Vitro through a Novel Receptor Distinct from a Type I or Type II PTH/PTHrP Receptor

PTH and PTH-related peptide (PTHrP) bind to a type I PTH/PTHrP receptor expressed in bone and kidney or a type II receptor in nonclassical target tissue with equal affinity and similar bioactivities. PTHrP is abundant in the central nervous system, but its physiological role remains unknown. Herein, we examined the role of PTHrP-(1–34) on arginine vasopressin (AVP) release from the rat supraoptic nucleus (SON). Application of PTHrP-(1–34) to SON slices caused an increase in AVP release in a concentration-dependent manner. Neither PTHrP-(7–34) nor PTH-(1–34) had any effect on AVP release from the SON. PTHrP-(1–34)-induced AVP release was antagonized by a large excess of PTHrP-(7–34) and by H89, an inhibitor of cAMP-dependent protein kinase (A kinase), but not by PTH-(1–34) or PTH-(13–34). PTHrP-(1–34), but not PTH-(1–34), also dose-dependently increased the levels of cAMP in the SON. 125I-Labeled PTHrP-(1–34) bound specifically to crude membranes isolated from the SON. Scatchard analysis showed a single cl...

Chinese medicinal herb, Acanthopanax gracilistylus, extract induces cell cycle arrest of human tumor cells in vitro

We investigated the effect of a Chinese medicinal herb, Acanthopanax gracilistylus (AG), extract (E) on the growth of human tumor cell lines in vitro. AGE markedly inhibited the proliferation of several tumor cell lines such as MT‐2, Raji, HL‐60, TMK‐1 and HSC‐2. The activity was associated with a protein of 60 kDa, which was purified by gel‐filtration chromatography. Cell viability analyses indicated that the treatment with AGE inhibits cell proliferation, but does not induce cell death. The mechanism of AGE‐induced inhibition of tumor cell growth involves arrest of the cell cycle at the G0/G1 Stage without a direct cytotoxic effect. The cell cycle arrest induced by AGE was accompanied by a decrease of phosphorylated retinoblastoma (Rb) protein. Furthermore, cyclin‐dependent kinases 2 and 4 (Cdk2 and Cdk4), which are involved in the phosphorylation of Rb, were also decreased. These results suggest that AGE inhibits tumor cell growth by affecting phosphorylated Rb proteins and Cdks.

Induction of expression of MHC-class-II antigen on human thyroid carcinoma by wild-type p53

Mutation of the tumor‐suppressor gene p53 is involved in carcinogenetics. We investigated the role of p53 in the induction of anti‐tumor immune responses by establishing a thyroid carcinoma cell line (1F3) prepared by transfection of wild‐type human p53 gene into a p53‐deficient cell line (FRO). Our results showed for the first time the involvement of p53 in the induction of anti‐tumor immune responses, as demonstrated by: (i) expression of the major‐histocompatibility‐complex(MHC)‐class‐II antigen on 1F3, but not FRO; (ii) mRNA of class‐II gene was expressed both in 1F3 and in FRO, but was stable at post‐transcriptional level in FRO, which restrained protein synthesis; (iii) 1F3 induced MHC‐class‐II‐specific CD4+ cytotoxic‐T‐cell activity through allo‐antigen presentation and co‐stimulation. Although our novel results are limited to the wild‐type‐p53‐expressing clone from a p53‐deficient cell line, we suggest that the absence of p53 in carcinoma cells may reduce the induction of CD4+ cytotoxic‐T‐cell activity against carcinoma cells by diminishing the expression of class‐II antigen. Int. J. Cancer 75:391–395, 1998.

Stimulatory Effect of Interleukin‐1α on Proliferation through a Ca2+/Calmodulindependent Pathway of a Human Thyroid Carcinoma Cell Line, NIM 1

NIM 1 cells, a human thyroid cell line established from a patient with thyroid papillary adenocarcinoma, produce cytokines such as interleukin‐1α (IL‐1α) and granulocyte‐colony stimulating factor. In the present study, we investigated the signal transduction pathway in the proliferation of NIM 1 cells evoked by IL‐1α. Incubation of NIM 1 cells with IL‐1α for 48 h increased the incorporation of 3H‐thymidine (3H‐TdR). The stimulatory effect of IL‐1α was evident at 0.01 ng/ml and the maximal effect was seen at 10 ng/ml. IL‐1α evoked an influx of 45Ca into NIM 1 cells within 3 min in a concentration‐dependent manner (0.01–1 ng/ml). These stimulatory effects of IL‐1α on both 3H‐TdR incorporation and 45Ca influx were similarly inhibited by nicardipine, an inhibitor of voltage‐dependent Ca2+ channels, in a concentration‐dependent manner (10–1000 nM). The stimulatory effect of IL‐1α on 3H‐TdR incorporation was inhibited by N‐(6‐aminohexyl)‐5‐chloro‐1‐naphthalenesulfonamide (W‐7), an antagonist of calmodulin, but not by 1‐(5‐isoquinoline sulfonyl)‐2‐methylpiperazine (H‐7), an inhibitor of protein kinase C. While the culture medium initially contained 0.75 mM Ca2+, inhibition of 3H‐TdR incorporation by nicardipine and W‐7 under these baseline conditions was also recognized. These results suggest that IL‐1α stimulates cell proliferation through a Ca2+/calmodulin‐dependent pathway in NIM 1 cells.

The effect of plasma exchange on the skin lesions in systemic lupus erythematosus.

The clinical effects and the changes of laboratory data after plasma exchange (PE) in 11 patients with systemic lupus erythematosus (SLE) refractory to the corticosteroid and other drug therapy were investigated.After several PEs, 8 out of 11 patients clinically improved especially in the skin lesions, namely butterfly-shaped skin rashes or skin ulcers and so on.And the decrease of the antibody to DNA and immune complex was significantly correlated with the degree of the clinical improvement.Furthermore, the intensity of anti-endothelial cell antibody demonstrated by the indirect immunofluorescent method, which was different from antibody to DNA or immune complex, was closely related to the skin lesions of SLE. But the change of the intensity of anti-endothelial cell antibody and the degree of the improvement of skin lesions are not necessarily correlated and this reason remains to be elucidated.