Biomedical subjects

T Tamatani

Publications and source records attributed to T Tamatani.

At least 19 recordsLinked to original sources

PubMed2003

Cisplatin induces apoptosis in oral squamous carcinoma cells by the mitochondria-mediated but not the NF-kappaB-suppressed pathway.

Cisplatin (CDDP) is a potent DNA-damaging anticancer agent, and its cytotoxic action is exerted by the induction of apoptosis. However, activation of the transcription factor NF-kappaB results in protection against apoptosis. We examined the molecular mechanisms involved in the induction of apoptosis by CDDP as regards both suppression of NF-kappaB and activation of caspases. Human oral squamous carcinoma cells (B88) were employed in this study. We found that CDDP treatment affected neither NF-kappaB activity nor the expression levels of antiapoptotic proteins, including TRAF-1, TRAF-2, and cFLIP, in B88 cells. However, two apoptosome molecules, cytochrome c and Apaf-1, were significantly augmented in the cytoplasm by CDDP treatment. Further, the activation of caspase-9 and caspase-3, downstream molecules leading to mitochondria-mediated apoptosis, were detected after treatment with CDDP. Finally, apoptosis was also clearly observed, as evidenced by cleavage of PARP through the activation of caspase-3. These findings suggest that CDDP exerts its apoptotic action by the mitochondria-mediated activation of caspases but not by the activation of caspases due to the inhibition of NF-kappaB activity that follows the suppression of antiapoptotic proteins.

Antineoplastic Agents↗

PubMed2001

Enhanced IkappaB kinase activity is responsible for the augmented activity of NF-kappaB in human head and neck carcinoma cells.

The nuclear transcription factor kappaB (NF-kappaB) plays an important role in the development and progression of cancers. However, the mechanism by which cancer cells in the head and neck region acquire high NF-kappaB activity has not yet been clarified. In this study, we examined the NF-kappaB binding activity and the expression of the signal-transduction-related proteins of NF-kappaB in head and neck carcinoma cell lines. These cancer cells showed significantly higher NF-kappaB binding activity than normal oral epithelial and salivary gland cells. We also demonstrated the increased phosphorylation and degradation of IkappaB-alpha protein in cancer cells. Thus, enhanced NF-kappaB activity in cancer cells is attributable to the rapid phosphorylation and degradation of IkappaB-alpha protein. To further elucidate the mechanism involved in this phenomenon, we analyzed both the expression levels of upstream kinases (IkappaB kinase- (IKK-) alpha, IKK-beta, IKK-gamma, and NF-kappaB-inducing kinase (NIK)) and the IKK activity in cells. Although there was no significant difference in the expression levels of NIK, IKK-beta, or IKK-gamma in cancer cell lines compared to those in normal cells, increased expression of IKK-alpha protein was observed in cancer cells. In addition, IKK activity was significantly augmented in cancer cells as compared to normal cells. Thus, our results suggest that enhanced NF-kappaB activity in head and neck cancer cells may be due to the augmentation of IKK activity.

Carcinoma, Squamous Cell↗

PubMed2001

5-Fluorouracil suppression of NF-KappaB is mediated by the inhibition of IKappab kinase activity in human salivary gland cancer cells.

We have recently shown that 5-Fluorouracil (5-FU) suppresses the transcription factor NF-kappaB in human salivary gland cancer cells (cl-1) by mediating upregulation of IkappaB-alpha expression. However, the precise mechanism involved in this action has not yet been elucidated. IkappaB kinases (IKK-alpha and IKK-beta) are the key components of the IKK complex that mediates activation of NF-kappaB in response to external stimuli such as cytokines. In addition, NF-kappaB-inducing kinase (NIK) and mitogen-activated protein kinase kinase kinase 1 (MEKK-1), both of which are the upstream kinases for the IKKs, interact with and activate the IKKs. Thus, we investigated the molecular mechanisms involved in the suppression of NF-kappaB by 5-FU. Although 5-FU did not affect the expression levels of IKKs, NIK, or MEKK-1, IKK activity in cl-1 cells was suppressed at both 6 h and 12 h after treatment with 2 microgram/ml 5-FU. Moreover, when cells were treated with various concentrations of 5-FU for 12 h, the concentration of 2 microgram/ml efficiently inhibited the IKK activity as compared to 1, 5, or 10 microgram/ml. The expression of Fas-associated death domain-like interleukin 1-converting enzyme-inhibitory protein (FLIP), which acts as an inhibitor of an initiator caspase (caspase-8), was down-regulated by 5-FU treatment in cl-1 cells. Apoptosis, as evidenced by cleavage of poly(ADP-ribose) polymerase through the action of an executioner caspase (caspase-3), was also clearly observed. Thus, these results suggest that 5-FU induction of apoptosis in cl-1 cells may be mediated by suppression of NF-kappaB via inhibition of IKK activity.

Fluorouracil↗

PubMed2001

Role of peroxisome proliferator-activated receptor gamma and its ligands in non-neoplastic and neoplastic human urothelial cells.

Peroxisome proliferator-activated receptor gamma (PPARgamma) is a member of the nuclear receptor superfamily of ligand-activated transcription factors and is expressed in several types of tissue. Although PPARgamma reportedly is expressed in normal urothelium, its function is unknown. We examined the expression of PPARgamma in normal urothelium and bladder cancer in an attempt to assess its functional role. Immunohistochemical staining revealed normal urothelium to express PPARgamma uniformly. All low-grade carcinomas were positive either diffusely or focally, whereas staining was primarily focal or absent in high-grade carcinomas. A nonneoplastic urothelial cell line (1T-1), a low-grade (RT4) carcinoma cell line, and two high-grade (T24 and 253J) carcinoma cell lines in culture expressed PPARgamma mRNA and protein. Luciferase assay indicated that PPARgamma was functional. PPARgamma ligands (15-deoxy-Delta(12,14)-prostaglandin J(2), troglitazone and pioglitazone) suppressed the growth of nonneoplastic and neoplastic urothelial cells in a dose-dependent manner. However, neoplastic cells were more resistant than were nonneoplastic cells. Failure to express PPARgamma or ineffective transcriptional activity may be some of the mechanisms responsible for resistance to the inhibitory action of PPARgamma ligands.

Aged↗

PubMed2001

Effect of a mutant form of IkappaB-alpha on 5-fluorouracil-induced apoptosis in transformed human salivary gland cells.

Increasing evidence indicates that transcription factor NF-kappaB may play a role in cell survival, and that some chemotherapeutic agents activate NF-kappaB, while inhibition of NF-kappaB renders cells sensitive to these drugs. 5-Fluorouracil (5-FU) exerts its cytotoxic effect through the induction of apoptosis. However, it still remains uncertain whether 5-FU treatment in combination with the inhibition of NF-kappaB largely exerts an anti-proliferative effect on the growth of neoplastic human salivary gland cells. Thus, we investigated whether NF-kappaB suppression in transformed human salivary gland (NS-SV-AC) cells leads to a marked reduction in cell growth in response to 5-FU treatment. Our results demonstrated that under unstimulated conditions, the ability of cell growth in the super-repressor form of IkappaB-alpha (srIkappaB-alpha) cDNA-transfected cell clones (ACMT-6 and -7) was significantly lower than that in the empty vector-transfected cell clone (ACpRc-1). In addition, the growth inhibition caused by 5-FU was greatly enhanced in ACMT-6 and -7 as compared to ACpRc-1. Based on fractional inhibition analysis, this growth inhibition was due to an additive effect of both inhibitors. Electrophoretic mobility shift assay revealed that NF-kappaB activity in these cell clones was not affected by treatment with 5-FU. Accordingly, our data provide evidence that the combination of 5-FU and NF-kappaB suppression cooperatively functions in the growth inhibition of NS-SV-AC cells.

Antimetabolites, Antineoplastic↗

PubMed2001

AILIM/ICOS: its expression and functional analysis with monoclonal antibodies.

Activation-inducible lymphocyte immuno-mediatory molecule (AILIM/ICOS) is the third member of the co-stimulatory molecule CD28/CTLA-4 (CD152) family, and an inducible cell surface glycoprotein expressed on lymphocytes following activation. To determine the expression profile of the molecule, we generated monoclonal antibodies (MAbs) against human, rat, and mouse AILIM/ICOS. None of the MAbs bound to AILIM/ICOS of other species. The numbers of AILIM/ICOS-positive cells among human peripheral blood mononuclear cells (PBMC), and rat and mouse splenocytes were very low (0.5, 0.4, and 1.2%, respectively), and the cells included many CD4-positive T cells except in the case of rat. Rat AILIM/ICOS-positive cells among splenocytes included many CD45RA-positive B cells, although the expression on lymph node cells was similar to that on human PBMC and mouse splenocytes. Among rat thymocytes, the AILIM/ICOS expression was mainly localized on CD4- and CD8-double positive T cells. The binding of AILIM/ICOS to B7h-Ig, which is the ligand-Fc chimeric protein, was inhibited by all AILIM/ICOS-specific MAbs except for SG430. The potency of the co-stimulatory activity of CD3 and AILIM/ICOS as to T-cell proliferation was found to be substantial in human. Interestingly, the levels of stimulation with the two types of MAbs were equal to that with CD3 and CD28 despite the different functions of the two MAbs in the AILIM/ICOS-B7h interaction. On the other hand, the potencies in rat and mouse, although two independent MAbs were tested, were relatively lower than that of CD28-mediated co-stimulation.

Animals↗

PubMed2001

Roles of carbon monoxide in leukocyte and platelet dynamics in rat mesenteric during sevoflurane anesthesia.

BACKGROUND: Heme oxygenase 1 (HO-1), induced by a variety of stressors, provides endogenous carbon monoxide (CO) and bilirubin, both of which play consequential roles in organs. The current study aimed to examine whether induction of HO-1 and its by-products modulated endothelial interaction with circulating leukocytes and platelets evoked by sevoflurane anesthesia in vivo. METHODS: Rats, pretreated with or without hemin, were anesthetized with sevoflurane in 100% O2, and lungs were mechanically ventilated. Platelets labeled with carboxyfluorescein diacetate succinimidyl ester and leukocyte behavior in mesenteric venules were visualized during sevoflurane anesthesia at 1,000 frames/s using intravital ultrahigh-speed intensified fluorescence videomicroscopy. To examine the mechanisms for the effects of HO-1 on leukocyte and platelet behavior, these studies were repeated with superfusion of either CO, bilirubin, or Nomega-nitro-L-arginine methyl ester (L-NAME). RESULTS: As reported previously, the elevation of sevoflurane concentration evoked adhesive responses of leukocytes, concurrent with platelet margination and rolling. Pretreatment with hemin, a HO-1 inducer, prevented such sevoflurane-elicited changes in the microvessels. These changes were restored by zinc protoporphyrin IX, a HO inhibitor, and repressed by CO but not by bilirubin. During sevoflurane anesthesia, however, nitric oxide suppression by L-NAME deteriorated microvascular flows irrespective of the presence or absence of the HO-1 induction. CONCLUSIONS: These results indicate that endogenous CO via HO-1 induction attenuates sevoflurane-induced microvascular endothelial interactions with leukocytes and platelets, although local nitric oxide levels appear to dominate microvascular flow in situ.

Anesthesia, Inhalation↗

PubMed2001

Tissue-specific induction of E-selectin in glomeruli is augmented following diabetes mellitus.

We recently demonstrated that induction of adhesion molecules is tissue, cell type, and blood vessel size specific. We examined here whether the glomeruli, a peculiar vascular system, express adhesion molecules in a specific manner in the murine kidney. In addition, since serum levels of soluble adhesion molecules have been reported to be elevated in diabetic patients, we examined the influence of diabetes mellitus on the induction of adhesion molecules in the kidney. Analysis of E-selectin mRNA expression by in situ hybridization indicated that it was selectively induced in glomeruli by intravenous administration of interleukin-1beta, while ICAM-1 mRNA expression was seen diffusely in endothelium lining the small arteries and capillaries or in glomeruli, and VCAM-1 mRNA expression was most prominent in endothelial cells of larger blood vessels. Induction of E-selectin mRNA expression in glomeruli by proinflammatory stimuli was augmented in streptozotocin-induced diabetic mice as compared with control mice, while ICAM-1 or VCAM-1 mRNA induction was only slightly influenced. Furthermore, immunohistochemical analysis showed that selective expression of E-selectin in glomeruli was augmented predominantly in epithelial cells, depending on the duration of diabetes mellitus, in KK-Ay mice. These findings suggest that glomerulus-specific expression of E-selectin is related to the development of diabetic nephropathy.

Animals↗

PubMed2000

P- and E-selectins recognize sialyl 6-sulfo Lewis X, the recently identified L-selectin ligand.

Recently we identified sialyl 6-sulfo Le(x) as a major L-selectin ligand on high endothelial venules of human peripheral lymph nodes. In this study we investigated the ligand activity of sialyl 6-sulfo Le(x) to E- and P-selectins and compared it with the binding activity of conventional sialyl Le(x), by using cultured human lymphoid cells expressing both carbohydrate determinants. The results of the recombinant selectin binding studies and the nonstatic monolayer cell adhesion assays indicated that both sialyl 6-sulfo Le(x) and conventional sialyl Le(x) served as ligand for E- and P-selectins, while L-selectin was quite specific to sialyl 6-sulfo Le(x). Anti-PSGL-1 antibodies as well as O-sialoglycoprotein endopeptidase treatment almost completely abrogated the binding of P-selectin but barely affected the binding of E-selectin, indicating that these carbohydrate determinants carried by O-glycans of PSGL-1 selectively serves as a ligand for P-selectin, while the ligand for E-selectin is not restricted to PSGL-1 nor to O-sialoglycoprotein endopeptidase-sensitive glycans. The binding of L-selectin was markedly reduced by O-sialoglycoprotein endopeptidase treatment but only minimally affected by anti-PSGL-1 antibodies, indicating that O-glycans carrying sialyl 6-sulfo Le(x) were the major L-selectin ligands, while PSGL-1 was only a minor core protein for L-selectin in these cells. These results indicated that each member of the selectin family has a distinct ligand binding specificity.

Animals↗

PubMed2000

Roles of P-selectin in inflammation, neointimal formation, and vascular remodeling in balloon-injured rat carotid arteries.

BACKGROUND: P-selectin plays key roles in mediating inflammation through promoting adherence of leukocytes to activated platelets and endothelium. This process is one of the initial events in atherosclerosis and restenosis after coronary angioplasty. METHODS AND RESULTS: Using a rat balloon-injury model, we examined the role of P-selectin in vascular inflammatory processes. In the acute phase, immunohistochemistry revealed that P-selectin was intensely expressed on both activated platelets covering the denuded segment and endothelial cells of the inflamed adventitial small vessels. Treatment with an anti-P-selectin monoclonal antibody (MAb) for 8 consecutive days significantly inhibited neointimal formation at day 14 (42% inhibition; P:<0.05), and this effect persisted at day 56 (40% inhibition; P:<0.01) compared with the control group. Vascular shrinking accompanying adventitial fibrosis was also attenuated at day 56. Inhibition of both neointimal formation and vascular shrinking resulted in the lumen area of the anti-P-selectin treatment group being approximately 3 times larger at day 56 than that of the control group. Accumulation of CD45-positive leukocytes in the developing neointima, media, and adventitia at day 8 was significantly inhibited by treatment with the anti-P-selectin MAb. Scanning electron microscopy demonstrated that anti-P-selectin treatment resulted in a less thrombogenic surface of the arterial intima, which featured a pseudoendothelial appearance at day 14 after injury. CONCLUSIONS: These results suggest that inhibition of P-selectin-mediated leukocyte recruitment prevents the development of neointimal formation, adventitial inflammation, and vascular shrinking and promotes pseudoendothelialization by luminal smooth muscle cells. This treatment thus beneficially affects vascular remodeling after balloon injury in rats.

Angioplasty, Balloon↗

PubMed2000

Identification and characterization of rat AILIM/ICOS, a novel T-cell costimulatory molecule, related to the CD28/CTLA4 family.

Activation-inducible lymphocyte immuno-mediatory molecule (AILIM) is an inducible cell surface glycoprotein expressed on thymocytes and activated lymphocytes. Specific monoclonal antibody to rat AILIM induced the cell aggregation of a rat thymoma cell line and ConA-activated splenocytes. In the present study, we identified the primary structure of two species of rat AILIM by expression cloning. We also cloned mouse and human AILIM homologues and the predicted amino acid sequences were identical to those of the inducible costimulator ICOS/CRP-1, which belongs to the CD28/CTLA4 family. Although the human and mouse AILIM/ICOS molecule is localized on T-cells, the major population of AILIM/ICOS-positive cells in rat splenocyte was CD45RA-positive B-cells. The expression level of AILIM/ICOS on T-cells was relatively low; however, its expression was drastically induced by the treatment with PMA plus Ca-ionophore or the engagement of CD3 and these costimulatory molecules. Almost all T-cells exhibited potency as to its expression. Functional analysis of AILIM/ICOS demonstrated that AILIM-mediated costimulation was relatively weak compared to that of human.

Abatacept↗

PubMed2000

5-Fluorouracil induces apoptosis through the suppression of NF-kappaB activity in human salivary gland cancer cells.

Activation of the transcription factor NF-kappaB results in protection against apoptosis, and the chemotherapeutic agent 5-Fluorouracil (5-FU) exerts its cytotoxic effect through the induction of apoptosis. Thus, we examined whether 5-FU could induce apoptosis through the suppression of NF-kappaB activity. We found that upon treatment of a human salivary gland cancer cell line (cl-1) with 5-FU, the NF-kappaB activity was suppressed in a time-dependent manner. This inhibition was mediated by a prevention of the degradation of the inhibitory IkappaB-alpha protein. In addition, the expression of TRAF-2 and cIAP-1, which are transcriptionally regulated by NF-kappaB and function as anti-apoptotic molecules through the interruption of caspase pathway, was also inhibited by 5-FU. Finally, the activity of caspase-8 and caspase-3 showed a significant increase in response to 5-FU. By flow cytometric analysis, 5-FU did not affect the expression level of Fas on the cell surface. Thus, our results suggest that one of the molecular mechanisms involved in 5-FU-induced apoptosis in cl-1 cells may be due to the suppression of NF-kappaB activity, resulting in the activation of the pro-apoptotic pathway.

Antimetabolites, Antineoplastic↗

PubMed2000

Immunoneutralization of glycoprotein Ibalpha attenuates endotoxin-induced interactions of platelets and leukocytes with rat venular endothelium in vivo.

This study aimed to examine molecular mechanisms for endotoxin-induced adhesive changes in platelets in vivo. Platelets labeled with carboxyfluorescein diacetate succinimidyl ester were visualized in rat mesenteric venules through intravital microscopy assisted by a high-speed fluorescence video imager at 1000 frames per second or by a normal-speed intensifier under monitoring of erythrocyte velocity. Leukocyte rolling was examined by normal-speed transmission video images. The velocity of platelets traveling along the centerline of venules followed that of erythrocytes, whereas that measured at the periendothelial space was significantly smaller than the erythrocyte velocity; a majority of these cells exhibited transient but notable rolling with endothelium. Administration of endotoxin increased the density of periendothelial platelets and reduced the rolling velocities of platelets and leukocytes in venules: All events were attenuated by anti-rat P-selectin monoclonal antibody s789G or by anti-human glycoprotein (GP) Ibalpha monoclonal antibody GUR83/35, which blocks ristocetin-induced aggregation of rat platelets. Isolated rat platelets injected into endotoxin-pretreated rats were able to roll on the venules. This event was attenuated by pretreatment of platelets in vitro with GUR83/35 but not with s789G, suggesting involvement of endothelial P-selectin and platelet GP Ibalpha in the endotoxin-induced responses. Furthermore, isolated human platelets showed similar rolling interactions with endotoxin-preexposed rat venules, and pretreatment of the platelets with GUR83/35, but not with s789G, significantly reduced such interactions. Our results provide the first evidence for involvement of GP Ibalpha in endotoxin-induced microvascular rolling of platelets and leukocytes, and this system serves as a potentially useful tool to examine GP Ibalpha-associated function of human platelets in vivo.

Animals↗

PubMed2000

Suppression of tumor necrosis factor alpha-induced matrix metalloproteinase 9 production by the introduction of a super-repressor form of inhibitor of nuclear factor kappaBalpha complementary DNA into immortalized human salivary gland acinar cells. Prevention of the destruction of the acinar structure in Sjögren's syndrome salivary glands.

OBJECTIVE: We have previously shown that specific enhancement in acinar cells of proteolytic activity induced by tumor necrosis factor alpha (TNFalpha) may be responsible for the destruction of the acinar structure in the salivary glands of patients with Sjögren's syndrome. Because matrix metalloproteinase 9 (MMP-9) is regulated by nuclear factor kappaB (NF-kappaB), we investigated the effect of a super-repressor form of inhibitor of nuclear factor kappaBalpha (srIkappaBalpha) on the suppression of TNFalpha-induced MMP-9 production in acinar cells. METHODS: Two srIkappaBalpha complementary DNA (cDNA)-transfected acinar cell clones (ACMT-6 and ACMT-7) and 1 empty vector-transfected cell clone (ACpRc-1) were established. After treatment of cell clones with TNFalpha, the expression of MMP-9 was examined. In addition, the effect of TNFalpha on cell growth and the morphogenetic behavior of cell clones cultured on type IV collagen-coated dishes were examined. RESULTS: TNFalpha induced the production of MMP-9 in the ACpRc-1 cell clone, but greatly suppressed MMP-9 production in ACMT-6 and ACMT-7 clones. No apparent cytotoxic effect of TNFalpha treatment was observed in these cell clones. When ACpRc-1 cells were seeded on type IV collagen-coated dishes in the presence of both TNFalpha and plasmin, type IV collagen interaction with the cells was lost and the cells entered apoptosis. However, even when ACMT-6 and ACMT-7 cells were cultured under the same culture conditions as those for ACpRc-1, these cell clones attached to the substrate and grew consistently without showing apoptosis. Conclusion. These observations indicate that suppression of TNFalpha-induced MMP-9 production by the introduction of srIkappaBalpha cDNA corrected the aberrant in vitro morphogenesis of acinar cells grown on type IV collagen.

Blotting, Western↗

PubMed2000

Expression of cutaneous lymphocyte-associated antigen regulated by a set of glycosyltransferases in human T cells: involvement of alpha1, 3-fucosyltransferase VII and beta1,4-galactosyltransferase I.

Cutaneous lymphocyte-associated antigen (CLA), which plays a key part in skin homing of human CD4+ memory T cells via CLA/E-selectin binding, is upregulated by IL-12 and downregulated by IL-4. Although alpha1,3-fucosyltransferase VII is essential for synthesis of the CLA carbohydrate epitope, little is known about how the CLA expression is regulated by a number of glycosyltransferases. A 6 wk long-term culture for the in vitro differentiation of naïve Th cells to memory Th1 cells was employed. By repeated activation in the presence of IL-12, naïve T cells differentiated into memory Th1 cells, resulting in the upregulation of CLA expression. The switching of cytokine from IL-12 to IL-4 at three cycles resulted in a marked downregulation of CLA. The transcript levels of 16 glycosyltransferases and P-selectin glycoprotein ligand-1, all considered to be potentially involved in CLA synthesis, were determined after each cycle. The level of CLA expression was well correlated with the amounts of alpha1,3-fucosyltransferase VII and beta1,4-galactosyltransferase I. Both were upregulated by IL-12 and downregulated by IL-4. In particular, alpha1,3-fucosyltransferase VII levels decreased markedly in the presence of IL-4. P-selectin glycoprotein ligand-1 and Core 2 beta1, 6-N-acetylglucosaminyltransferase were progressively up-regulated by repeated IL-12 stimulation, but they were not downregulated by IL-4. The transcript levels of some genes examined were constitutive without any correlation to CLA expression. These results suggest that the level of CLA expression is determined by alpha1, 3-fucosyltransferase VII and beta1,4-galactosyltransferase I, the other enzymes merely participating in the synthesis of CLA. In peripheral blood mononuclear cells, IL-12 and IL-4 profoundly upregulated and downregulated the alpha1,3-fucosyltransferase VII transcripts, respectively, but not the beta1,4-galactosyltransferase I ones, within only 2 h of in vitro culture. This suggested that alpha1,3-fucosyltransferase VII is transcriptionally regulated directly by IL-12 and IL-4.

Antigens, Differentiation, T-Lymphocyte↗

PubMed2000

AILIM/ICOS: a novel lymphocyte adhesion molecule.

The adhesive interaction between T cells and antigen-presenting cells is required for the formation of the immunological synapse. Inducible co-stimulator (ICOS) is a third member of the CD28 family of co-stimulatory molecules. Here we describe a novel lymphocyte adhesion molecule, of relative molecular mass 47,000, designated AILIM, that is a rat homolog of ICOS. Rat AILIM was constitutively expressed on thymocytes and was induced on naive T cells after activation. Human thymoma cells bound to purified AILIM. Furthermore, cells transfected with the AILIM gene aggregated in an AILIM-dependent manner. These results suggest a novel function for AILIM/ICOS as an adhesion molecule, which plays an important role in T cell activation.

Animals↗

PubMed2000

Effects of CTGF/Hcs24, a product of a hypertrophic chondrocyte-specific gene, on the proliferation and differentiation of chondrocytes in culture.

Recently, we cloned a messenger RNA (mRNA) predominantly expressed in chondrocytes from a human chondrosarcoma-derived chondrocytic cell line, HCS-2/8, by differential display PCR and found that its gene, named hcs24, was identical with that of connective tissue growth factor (CTGF). Here we investigated CTGF/Hcs24 function in the chondrocytic cell line HCS-2/8 and rabbit growth cartilage (RGC) cells. HCS-2/8 cells transfected with recombinant adenoviruses that generate CTGF/Hcs24 sense RNA (mRNA) proliferated more rapidly than HCS-2/8 cells transfected with control adenoviruses. HCS-2/8 cells transfected with recombinant adenoviruses that generate CTGF/Hcs24 sense RNA expressed more mRNA of aggrecan and type X collagen than the control cells. To elucidate the direct action of CTGF/Hcs24 on the cells, we transfected HeLa cells with CTGF/Hcs24 expression vectors, obtained stable transfectants, and purified recombinant CTGF/Hcs24 protein from conditioned medium of the transfectants. The recombinant CTGF/Hcs24 effectively promoted the proliferation of HCS-2/8 cells and RGC cells in a dose-dependent manner and also dose dependently increased proteoglycan synthesis in these cells. In addition, these stimulatory effects of CTGF/Hcs24 were neutralized by the addition of anti-CTGF antibodies. Furthermore, the recombinant CTGF/Hcs24 effectively increased alkaline phosphatase activity in RGC cells in culture. Moreover, RT-PCR analysis revealed that the recombinant CTGF/Hcs24 stimulated gene expression of aggrecan and collagen types II and X in RGC cells in culture. These results indicate that CTGF/Hcs24 directly promotes the proliferation and differentiation of chondrocytes.

Adenoviridae↗

PubMed2000

Serum levels of connective tissue growth factor are elevated in patients with systemic sclerosis: association with extent of skin sclerosis and severity of pulmonary fibrosis.

OBJECTIVE: To determine the serum levels and clinical correlation of connective tissue growth factors (CTGF) in patients with systemic sclerosis (SSc). METHODS: Serum samples from patients with limited cutaneous SSc (lSSc, n = 32), diffuse cutaneous SSc (dSSc, n = 28), systemic lupus erythematosus (SLE, n = 30), polymyositis/dermatomyositis (PM/DM, n = 20), and healthy control subjects (n = 30) were examined by ELISA for detection of CTGF. RESULTS: Serum CTGF levels in patients with SSc were significantly higher than those in patients with SLE or PM/DM, and in controls. CTGF levels in patients with dSSc were significantly higher than those in patients with lSSc. As for clinical correlation of CTGF, SSc patients with elevated CTGF had pulmonary fibrosis, decreased DLCO, and decreased vital capacity more frequently than those with normal CTGF levels. Further, DLCO and vital capacity were inversely and directly correlated with serum CTGF levels in patients with SSc. The dSSc patients with disease duration of 1-3 years had significantly elevated levels of CTGF compared with dSSc patients with duration < 1 year or more than 3 years. CONCLUSION: Serum CTGF levels were increased in patients with SSc, and correlated with the extent of skin sclerosis and the severity of pulmonary fibrosis. In addition, it appears that production of CTGF is involved in the development or maintenance of fibrosis rather than in initiation of fibrosis in SSc. These data suggest that CTGF plays a critical role in the development of fibrosis in SSc.

Adolescent↗