Biomedical subjects

Yukio Kato

Publications and source records attributed to Yukio Kato.

At least 19 recordsLinked to original sources

PubMed2006

Characterization of the hepatic disposition of lanoteplase, a rationally designed variant of tissue plasminogen activator in rodents.

Lanoteplase is a recombinant mutant of tissue-type plasminogen activator (t-PA) that was developed with an aim to overcome the drawback of rapid systemic elimination of t-PA. In this study, we examined the disposition profile of lanoteplase in vivo and the kinetics of receptor-mediated endocytosis (RME) of this recombinant t-PA in vitro to kinetically characterize the mechanism(s) underlying its tissue distribution and elimination. Integration plot analysis of the initial-phase tissue distribution in rats revealed a much lower uptake clearance (CL(uptake)) of lanoteplase in the liver than that of t-PA. Rate constants for cell surface binding, internalization, and degradation of lanoteplase were also lower than those for t-PA in primary cultured rat hepatocytes. These results suggest that the improved stability of lanoteplase in vivo could be accounted for by the delay in the RME of this recombinant protein. The CL(uptake) in the liver decreased with coadministration of lactoferrin, a ligand for the low-density lipoprotein receptor-related protein (LRP) and the asialoglycoprotein (ASGP) receptors in normal mice, and in lrpap1((-/-)) mice, which have a hereditary deficiency of LRP; In contrast, CL(uptake) was not affected by mannose, whereas that of t-PA decreased with both ligands and in the lrpap1((-/-)) mice. Thus, the hepatic disposition of lanoteplase seems to be mediated by common specific receptors for t-PA, including LRP and the ASGP receptors, whereas the mannose receptor seems to be only minimally involved in the disposition of lanoteplase.

Animals↗

PubMed2006

Functional expression of stereoselective metabolism of cephalexin by exogenous transfection of oligopeptide transporter PEPT1.

Gastrointestinal absorption of the beta-lactam antibiotic cephalexin (CEX) is highly stereoselective: l- and d-CEX are both taken up by intestinal epithelial cells through the brush-border membrane, most likely via oligopeptide transporter PEPT1, but l-CEX is not found in serum or urine after administration p.o. because of its rapid intestinal metabolism, whereas d-CEX is well absorbed in the unchanged form. We examined the contribution of PEPT1 to the stereoselective uptake and metabolism of CEX. We observed stereoselective metabolism of CEX after exogenous transfection of PEPT1 alone into mammalian cell lines: l-CEX, but not d-CEX, was metabolized to 7-aminodesacetoxycephalosporanic acid (7-ADCA) in HeLa and human embryonic kidney 293 cells stably and transiently expressing human PEPT1, respectively, whereas such metabolism was minor in cells expressing the vector alone. The formation rate of 7-ADCA depended on the amount of PEPT1 cDNA transfected. l-CEX metabolism was rapid because only 7-ADCA was found inside and outside the cells during incubation with l-CEX. The characteristics of PEPT1-mediated metabolism of l-CEX were similar, but not identical, to those of PEPT1-mediated transport. PEPT1-mediated metabolism was also observed in permeabilized cells expressing PEPT1, in which PEPT1-mediated intracellular substrate accumulation was negligible, suggesting that the increase in l-CEX metabolism by PEPT1 transfection cannot be fully explained by an increase in uptake and subsequent exposure to intracellular hydrolases. The present findings show that stereoselectivity in CEX absorption can be fully explained in terms of PEPT1, implying that the l-CEX hydrolase is PEPT1 itself or is induced by PEPT1.

Anti-Bacterial Agents↗

PubMed2006

Expression of porcine FSHbeta subunit promoter-driven herpes simplex virus thymidine kinase gene in transgenic rats.

A transgenic rat was established using the construct of porcine FSHbeta subunit promoter, the -852/+10 bp region, fused to a Herpes simplex virus thymidine kinase (HSV-TK) gene. Integration of the transgene was confirmed by PCR of tail DNA. RT-PCR of total RNAs of the pituitary, gonad, cerebellum, liver, kidney, adrenal gland, prostate, and uterus revealed that FSHbeta was only expressed in the pituitary. Analysis of the expression of reporter gene, HSV-TK, using two specific primer sets revealed that different transcripts were present in the pituitary and testis. The transcript initiated at the transcription initiation site of the porcine FSHbeta gene was detected in the pituitary, and another within the TK gene was found in the testis, indicating ectopic testis-specific expression. Immunohistochemistry of the pituitary glands of the transgenic rats for FSH and HSV-TK demonstrated that the FSH-producing cells also produced HSV-TK. The results indicated that the -852/+10 bp region of the FSHbeta promoter contains an element(s) that determines the tissue-specific expression. We succeeded in producing FSHbeta promoter-driven HSV-TK transgenic rats and were the first time to do so using an animal other than the mouse. The transgenic rats show male infertility that involves abnormal spermatogenesis. We also observed a decrease in the weight of the testis and epididymis, and both motile and living spermatozoa were absent in the epididymis. Consequently, the FSHbeta-HSV-TK transgenic rat will provide a useful model for studies on FSH function and male infertility.

Animals↗

PubMed2006

Characterization of the uptake mechanism for a novel loop diuretic, M17055, in Caco-2 cells: involvement of organic anion transporting polypeptide (OATP)-B.

PURPOSE: M17055 is under development as a novel loop diuretic for oral administration. To investigate the molecular mechanism of its gastrointestinal absorption, we initially aimed to clarify the mechanism of uptake of M17055 by Caco-2 cells, focusing on possible involvement of OATP-B (SLCO2B1), which is localized in the apical membranes of human intestinal epithelial cells. MATERIALS AND METHODS: The uptake of [14C]M17055 by Caco-2 cells cultured on multi-well dishes was measured after cultivation for 14 days. Uptake of [14C]M17055 by HEK293 cells stably expressing OATP-B (HEK293/OATP-B cells) was also examined. RESULTS: M17055 uptake by Caco-2 cells was saturable, and was inhibited by various organic anions, including other loop diuretics, and several bile acids. Uptake of M17055 by HEK293/OATP-B cells was much higher than that by mock cells. The inhibitory profiles of various organic anions and the estimated Km values for M17055 uptake were similar in Caco-2 and HEK293/OATP-B cells. Moreover, the values of inhibition constants of several inhibitors for M17055 uptake were comparable in the two cell lines. CONCLUSION: Our data suggest that OATP-B plays a major role in the uptake of the novel loop diuretic M17055 from apical membranes in Caco-2 cells.

Algorithms↗

PubMed2006

Site-dependent contributions of P-glycoprotein and CYP3A to cyclosporin A absorption, and effect of dexamethasone in small intestine of mice.

We examined whether the oral bioavailability of cyclosporin A is controlled primarily by P-glycoprotein (P-gp) or CYP3A in the small intestine. In situ loop method was used to evaluate the uptake of cyclosporin A (40nmol) at the upper and lower intestine of wild-type and mdr1a/1b knockout mice treated or not treated with dexamethasone (75mg/kg/day, 7 days, i.p.). Expression of CYP3A mRNA in the control group was higher in the upper than the lower intestine, while that of the multidrug resistance-1a (mdr1a) mRNA was in the opposite order. Dexamethasone administration potently induced CYP3A and mdr1a mRNAs in the lower and upper intestine, respectively. At 45min after cyclosporin A administration into an upper intestinal loop of the control group of wild-type mice, the ratio of residual cyclosporin A to dose did not differ significantly from that of mdr1a/1b knockout mice, whereas in dexamethasone-treated wild-type mice, the residual ratio was increased significantly. The ratio of the cyclosporin A metabolite M17 to cyclosporin A in portal venous blood at an upper intestinal loop of mdr1a/1b knockout mice was much higher than that a lower intestinal loop. The M17/cyclosporin A ratio of portal venous blood at a lower intestinal loop in mdr1a/1b knockout mice was increased significantly by dexamethasone treatment. These results suggest that, under physiological conditions, the oral bioavailability of cyclosporin A is mainly controlled by CYP3A in the upper intestine, rather than liver, but when P-gp is induced by steroid, the intestinal absorption of cyclosporin A may be inhibited.

ATP Binding Cassette Transporter, Subfamily B↗

PubMed2006

Cofactor CLIM2 promotes the repressive action of LIM homeodomain transcription factor Lhx2 in the expression of porcine pituitary glycoprotein hormone alpha subunit gene.

We have cloned a porcine orthologue of cofactor CLIM2 (Ldb1/NLI) from the porcine pituitary cDNA library by protein-protein interaction with the Yeast Two-Hybrid System using porcine Lhx2 as a bait protein. Porcine CLIM2 shows a high identity (99%) in the dimerization domain, nuclear localization signal and LIM binding domain with those of man and mouse. The expression of CLIM2 gene in the anterior pituitary lobe was detected during the porcine fetal and postnatal period by RT-PCR analysis, suggesting that this protein is constitutively expressing and plays a basic role in the anterior pituitary. Transfection assay to the pituitary tumor derived LbetaT2 cells, and the Chinese hamster ovary cells demonstrated that CLIM2 acts as a corepressor of the porcine Lhx2 function. Interestingly, CLIM2 alone apparently repressed the high level of alphaGSU gene expression in LbetaT2 cells. These data suggest that CLIM2 is a basic factor in the pituitary development and function, and plays the role of repressor to modify the function of Lhx2 on the alphaGSU gene expression.

Amino Acid Sequence↗

PubMed2006

PDZ adaptor protein PDZK2 stimulates transport activity of organic cation/carnitine transporter OCTN2 by modulating cell surface expression.

A part of the organic cation transporter families (OCT3, OCTN1, and OCTN2) has recently been identified to physically interact with PDZ (PSD95, Dlg, and ZO1) domain-containing proteins, although the physiological relevance of such interaction has not yet been fully examined. Here we have examined the stimulatory effect of PDZK2 [also named NaPi-Cap2 and intestinal and kidney-enriched PDZ protein (IKEPP)] on those cation transporters. In HEK293 cells, coexpression with PDZK2 increased the uptake of carnitine by OCTN2 with minimal effect on its substrate recognition specificity, but not for transport activity of OCT3 or OCTN1. The stimulatory effect of PDZK2 on OCTN2 was compatible with an approximately 2 times increase in transport capacity and can be accounted for by the increase in cell surface expression of OCTN2. Coexpression of PDZK2 did not affect carnitine transport activity of OCTN2 with deletion of the last four amino acids, which were found to be important for the interaction, suggesting involvement of physical interaction of the two proteins in the increase of cell surface expression of OCTN2. In mouse kidney, colocalization of PDZK2 and OCTN2 occurred predominantly in the region that was close to, but not the same as, the surface of apical membranes where OCTN2 alone was observed, suggesting the existence of OCTN2 in the subapical compartment that interacts with PDZK2. The present data have thus proposed an "intracellular pool" for OCTN2 that may be relevant to the stabilization of cell surface expression of OCTN2, thereby increasing transport activity for carnitine.

Adaptor Proteins, Signal Transducing↗

PubMed2006

Effects of fasting and re-feeding on the expression of Dec1, Per1, and other clock-related genes.

To elucidate the food-entrainable oscillatory mechanism of peripheral clock systems, we examined the effect of fasting on circadian expression of clock genes including Dec1 and Dec2 in mice. Withholding of food for 2 days had these effects: the expression level of Dec1 mRNA decreased in all tissues examined, although Per1 mRNA level markedly increased; Per2 expression was reduced in the liver and heart only 42-46 h after the start of fasting; and expression profiles of Dec2 and Bmal1 were altered only in the heart and in the liver, respectively, whereas Rev-erbalpha mRNA levels did not change significantly. Re-feeding after 36-h starvation erased, at least in part, the effect of fasting on Dec1, Dec2, Per1, Per2, and Bmal1 within several hours, and restriction feeding shifted the phase of expression profiles of all examined clock genes including Dec1 and Dec2. These findings indicate that short-term fasting and re-feeding modulate the circadian rhythms of clock genes to different extents in peripheral tissues, and suggest that the expression of Dec1, Per1, and some other clock genes was closely linked with the metabolic activity of these tissues.

Animals↗

PubMed2006

Role of SLC xenobiotic transporters and their regulatory mechanisms PDZ proteins in drug delivery and disposition.

Various types of xenobiotic (or drug) transporters have been recently identified to play important roles as barriers against toxic compounds and influx pumps to take up nutrients into the body. Since those xenobiotic transporters generally have wide range of recognition specificity and accept various types of compounds as substrates, localization and functional expression of such transporters could be one of the critical factors that affect the disposition and subsequent biological activity of therapeutic agents. Identification and characterization of drug transporters have given us a scientific basis for understanding drug delivery and disposition, as well as the molecular mechanisms of drug interaction and inter-individual/inter-species differences. To precisely understand pharmacological roles of the transporters in the body, it is also important to clarify molecular mechanisms involved in regulation of the transporters. As a first step to clarify the regulatory mechanisms that govern cell-surface expression and/or function of these transporters, recent researches have focused on PDZ (PSD-95/Discs-large/ZO-1) binding motif localized on carboxylic terminus of several types of xenobiotic transporters. Most of the transporters showing direct interaction potential with the PDZ domain-containing proteins are expressed on apical membranes in epithelial cells of kidney and/or small intestine, implying that such protein-protein interaction may play a role in apical localization of the transporters. In this mini-review article, we summarize importance of transporters and their regulatory mechanisms in drug delivery and disposition, focusing on several aspects of transporter-mediated drug targeting.

ATP-Binding Cassette Transporters↗

PubMed2006

Organic cation/carnitine transporter OCTN2 (Slc22a5) is responsible for carnitine transport across apical membranes of small intestinal epithelial cells in mouse.

The organic cation/carnitine transporter OCTN2 is responsible for renal tubular reabsorption of its endogenous substrate, carnitine, although its physiological role in small intestine remains controversial. Here we present direct evidence for a predominant role of OCTN2 in small intestinal absorption of carnitine based on experiments with juvenile visceral steatosis (jvs) mice, which have a hereditary deficiency of the octn2 gene. Uptake of carnitine, assessed with an Ussing-type chamber system, from the apical surface of the small intestine was saturable and higher than that from the basal surface in wild-type mice, whereas carnitine uptake having these characteristics was almost absent in jvs mice. Saturable uptake of carnitine was also confirmed in isolated enterocytes obtained from wild-type mice, and the Km value obtained (approximately 20 microM) was close to that reported for carnitine uptake by human embryonic kidney 293 cells stably expressing mouse OCTN2 (Slc22a5). The carnitine uptake by enterocytes was decreased in the presence of various types of organic cations, and this inhibition profile was similar to that of mouse OCTN2, whereas uptake of carnitine was quite small and unsaturable in enterocytes obtained from jvs mice. Immunohistochemical and immunoprecipitation analyses suggested colocalization of OCTN2 with PDZK1, an adaptor protein that functionally regulates OCTN2. Immunoelectron microscopy visualized both OCTN2 and PDZK1 in microvilli of absorptive epithelial cells. These findings indicate that OCTN2 is predominantly responsible for the uptake of carnitine from the apical surface of mouse small intestinal epithelial cells, and it may therefore be a promising target for oral delivery of therapeutic agents that are OCTN2 substrates.

Animals↗

PubMed2006

Predominant contribution of organic anion transporting polypeptide OATP-B (OATP2B1) to apical uptake of estrone-3-sulfate by human intestinal Caco-2 cells.

Human organic anion transporting polypeptide OATP-B (OATP2B1) is a pH-sensitive transporter expressed in the apical membranes of small intestinal epithelial cells. In this study, we have examined the contribution of OATP-B to the uptake of [3H]estrone-3-sulfate in Caco-2 cells in comparison with those of its homologs OATP-D (OATP3A1) and OATP-E (OATP4A1). Immunocytochemical study revealed that OATP-B is expressed in the apical membranes of Caco-2 cells. The uptake of [3H]estrone-3-sulfate by Caco-2 cells was Na+-independent and inhibited by several organic anions. It showed biphasic saturation kinetics with Km values of 1.81 microM and 1.40 mM. The uptake of [3H]estrone-3-sulfate by human embryonic kidney (HEK) 293 cells stably expressing OATP-B (HEK293/OATP-B) was also Na+-independent and inhibited by several organic anions. The Km value for estrone-3-sulfate uptake by OATP-B (1.56 microM) was close to that for the high-affinity component observed in Caco-2 cells. The mRNA expression level of OATP-B was higher than that of OATP-D or OATP-E in Caco-2 cells and in human jejunum biopsies from healthy volunteers. The values of [3H]estrone-3-sulfate uptake normalized to OATP-B mRNA expression were similar in Caco-2 cells and HEK293/OATP-B cells. The specific activity of OATP-B per mRNA expression was much higher than that of OATP-D and OATP-E. [3H]Estrone-3-sulfate uptake by membrane vesicles prepared from HEK293/OATP-B cells exhibited an overshoot phenomenon in the presence of an inwardly directed H+ gradient, suggesting that an H+ gradient is the driving force of estrone-3-sulfate transport by OATP-B. These results suggest that OATP-B is predominantly responsible for the apical uptake of estrone-3-sulfate in Caco-2 cells.

Adult↗

PubMed2006

Effects of overexpression of basic helix-loop-helix transcription factor Dec1 on osteogenic and adipogenic differentiation of mesenchymal stem cells.

We recently reported that forced expression of basic helix-loop-helix transcription factor Dec1 accelerated chondrogenic differentiation of mesenchymal stem cells (MSC) in pellet cultures (Shen, M., Yoshida, E., Yan, W., Kawamoto, T., Suardita, K., Koyano, Y., Fujimoto, K., Noshiro, M., Kato, Y., 2002. Basic helix-loop-helix protein DEC1 promotes chondrocyte differentiation at the early and terminal stages. J. Biol. Chem. 277, 50112-50120). Since MSC have multilineage differentiation potential, we investigated the roles of Dec1 in osteogenic and adipogenic differentiation of human bone marrow-derived MSC. After osteogenic induction of MSC in medium containing dexamethasone, beta-glycerophosphate, and ascorbic acid, Dec1 expression gradually increased from day 5 to day 14, while expression levels of Dec1 mRNA markedly decreased on days 3 and 7 after adipogenic induction. Infection with adenovirus expressing Dec1 raised mRNA levels of several bone characteristic molecules such as osteopontin, PTH receptor, and alkaline phosphatase, even in the absence of the osteogenic induction medium, although it had little effect on Runx2 expression or calcification. In the osteogenic induction medium, Dec1 overexpression enhanced the expression of osteopontin and alkaline phosphatase and induced matrix calcification. Knockdown of Dec1 with siRNA suppressed the expression of osteoblastic phenotype by the induced MSC. Using MSC cultures, we also confirmed that forced expression of Dec1 suppressed adipogenic differentiation. These findings suggest that Dec1 modulates osteogenic differentiation of MSC by inducing the expression of several, but not all, bone-related genes.

Adipogenesis↗

PubMed2006

Regulation of drug transporters by PDZ adaptor proteins and nuclear receptors.

Drug transporters have been suggested to be involved in various aspects of pharmacokinetics. Identification and characterization of drug transporters have given us a scientific basis for understanding drug disposition, as well as the molecular mechanisms of drug interaction and inter-individual/inter-species differences. On the other hand, regulatory mechanisms of drug transporters are still poorly understood, and information is limited to induction and down-regulation of drug transporters by various microsomal enzyme inducers. Little is known about the molecular machinery that directly interacts with the drug transporters. As a first step to clarify such molecular mechanisms, recent studies have identified PDZ (PSD-95/Discs-large/ZO-1) domain-containing proteins that directly interact with the so-called PDZ binding motif located at the C-terminus of drug transporters. Some of the PDZ proteins have been suggested to regulate transporters via at least two pathways, i.e. stabilization at the cell-surface and direct modulation of transporter function. Therefore, it is possible that membrane transport of therapeutic agents is not only governed by the drug transporters themselves, but also indirectly by PDZ proteins. The PDZ proteins are classified as a family, the members of which are thought to have distinct, but also redundant physiological roles. The purpose of this review article is to summarize the available knowledge on protein interactions and functional modulation of drug transporters.

Adaptor Proteins, Signal Transducing↗

PubMed2006

Carrier-mediated hepatic uptake of a novel nonrenal excretion type uric acid generation inhibitor, Y-700.

Y-700, a novel xanthine oxidase inhibitor, was recently developed for the treatment of hyperuricemia and gout. Since the major elimination route of this compound is hepatic metabolism and excretion, the aim of the present study was to characterize the uptake mechanism of Y-700 in the liver, which is also the pharmacological target of Y-700. Efficient uptake of Y-700 was observed both in the liver in vivo and in isolated rat hepatocytes. The uptake was Na(+)-dependent, saturable and inhibited both by ATP-depressants and various organic anions. Indomethacin competitively inhibited Y-700 uptake, whereas the inhibitory effect of organic cations and nucleosides was not so remarkable. Saturable and Na(+)-dependent uptake of Y-700 was also observed in freshly isolated human hepatocytes. Uptake of Y-700 by sinusoidal membrane transporters, such as organic anion transporter (Oat) 2 and organic anion transporting polypeptide (OATP)-B, OATP-C, OATP-8, and Oatp1, could not be detected although uptake of Y-700 in the oocytes expressing sodium/taurocholate cotransporting polypeptide (NTCP) was slightly observed. In conclusion, active transport system(s), which specifically recognize certain types of anionic compounds, are involved in the hepatic uptake of Y-700 and, at least partially, relevant to its elimination from the circulation as well as delivery to pharmacological target.

Animals↗

PubMed2006

Autologous bone marrow mononuclear cell implantation induces angiogenesis and bone regeneration in a patient with compartment syndrome.

A 28-year-old man developed compartment syndrome in the right lower leg after fracture of the tibia and fibula. Despite fasciotomy, many arteries collapsed and union of the tibial and fibula fractures did not occur. Autologous bone marrow mononuclear cell (BMMNC) implantation for therapeutic angiogenesis and subsequent bone regeneration was performed and 4 weeks later, angiography showed a marked increase in collateral vessels surrounding the tibial fracture, and union was completed 6 months later. BMMNC implantation therapy might provide therapeutic angiogenesis and osteogensis in patients with compartment syndrome.

Bone Marrow Transplantation↗

PubMed2006

Pituitary transcription factor Prop-1 stimulates porcine pituitary glycoprotein hormone alpha subunit gene expression.

Recently, we have reported that a Prophet of Pit-1 homeodomain factor, Prop-1, is a novel transcription factor for the porcine follicle-stimulating hormone beta subunit (FSHbeta) gene. This study subsequently aimed to examine the role of Prop-1 in the gene expression of two other porcine gonadotropin subunits, pituitary glycoprotein hormone alpha subunit (alphaGSU), and luteinizing hormone beta subunit (LHbeta). A series of deletion mutants of the porcine alphaGSU (up to -1059 bp) and LHbeta (up to -1277 bp) promoters were constructed in the reporter vector, fused with the secreted alkaline phosphatase gene (pSEAP2-Basic). Transient transfection studies using GH3 cells were carried out to estimate the activation of the porcine alphaGSU and LHbeta promoters by Prop-1, which was found to activate the alphaGSU promoter of -1059/+12 bp up to 11.7-fold but not the LHbeta promoter. Electrophoretic mobility shift assay and DNase I footprinting analysis revealed that Prop-1 binds to six positions, -1038/-1026, -942/-928, -495/-479, -338/-326, -153/-146, and -131/-124 bp, that comprise the A/T cluster. Oligonucleotides of six Prop-1 binding sites were directly connected to the minimum promoter of alphaGSU, fused in the pSEAP2-Basic vector, followed by transfecting GH3 cells to determine the cis-acting activity. Finally, we concluded that at least five Prop-1 binding sites are the cis-acting elements for alphaGSU gene expression. The present results revealed a notable feature of the proximal region, where three Prop-1-binding sites are close to and/or overlap the pituitary glycoprotein hormone basal element, GATA-binding element, and junctional regulatory element. To our knowledge, this is the first demonstration of the role of Prop-1 in the regulation of alphaGSU gene expression. These results, taken together with our previous finding that Prop-1 is a transcription factor for FSHbeta gene, confirm that Prop-1 modulates the synthesis of FSH at the transcriptional level. On the other hand, the defects of Prop-1 are known to cause dwarfism and combined pituitary hormone deficiency accompanying hypogonadism. Accordingly, the present observations provide a novel view to understand the hypogonadism caused by Prop-1 defects at the molecular level through the regulatory mechanism of alphaGSU and FSHbeta gene expressions.

AT-Hook Motifs↗

PubMed2006

Promotion of functioning of human periodontal ligament cells and human endothelial cells by nerve growth factor.

BACKGROUND: We have previously shown that cultured human periodontal ligament (HPL) cells produce nerve growth factor (NGF) and express mRNA of tyrosine kinase receptor (trkA), a high-affinity receptor of NGF. These findings suggest that NGF modulates the differentiation and proliferation of the periodontal ligament cells by paracrine and autocrine functions in vivo. Endothelial cells also express NGF and trkA. Therefore, NGF may regulate functions of periodontal ligament cells and endothelial cells during periodontal tissue regeneration. METHODS: Effects of NGF on expressions of bone/cementum-related proteins (osteocalcin [OC], bone sialoprotein [BSP], bone morphogenetic protein [BMP-7], core binding factor alpha [Cbfa-1], and type I collagen), calcification in HPL cells, and proliferation and mRNA expression of vascular endothelial growth factor (VEGF), an endothelial cell mitogen, in human microvascular endothelial cells (HMVECs) were examined. RESULTS: NGF elevated mRNA levels of OC, BSP, BMP-7, Cbfa-1, and type I collagen and enhanced mineral deposition in cultures of HPL cells. Furthermore, NGF stimulated mRNA expressions of VEGF-A and VEGF-B and cell proliferation in HMVEC. CONCLUSION: These findings suggest that the functional regulation of periodontal ligament cells and endothelial cells by NGF might result in the acceleration of periodontal tissue regeneration in vivo.

Bone Morphogenetic Proteins↗

PubMed2006

Behavior of transplanted bone marrow-derived mesenchymal stem cells in periodontal defects.

BACKGROUND: Recently, there have been an increased number of basic and clinical reports indicating the superior potential of bone marrow-derived mesenchymal stem cells (MSCs) for tissue regeneration. In periodontal treatment, previous animal studies indicated that autotransplantation of bone marrow MSCs into experimental periodontal defects enhanced periodontal tissue regeneration. However, mechanisms for periodontal tissue regeneration with MSCs are still unclear. The purpose of this study was to elucidate the behavior of transplanted MSCs in periodontal defects. METHODS: Bone marrow MSCs were isolated from beagle dogs, labeled with green fluorescent protein (GFP), and expanded in vitro. The expanded MSCs were mixed with atelocollagen (2% type I collagen) at final concentrations of 2 x 10(7) cells/ml and transplanted into experimental Class III periodontal defects. Localizations of GFP and proliferating cell nuclear antigen (PCNA)-positive cells were evaluated by immunohistochemical analysis. RESULTS: Four weeks after transplantation, the periodontal defects were almost regenerated with periodontal tissue. Cementoblasts, osteoblasts, osteocytes, and fibroblasts of the regenerated periodontal tissue were positive with GFP. PCNA-positive cells were present in regenerating connective tissue. CONCLUSION: These findings suggest that transplanted mesenchymal stem cells could survive and differentiate into periodontal tissue cells, resulting in enhancement of periodontal tissue regeneration.

Alveolar Process↗