A New Triggering Receptor Expressed on Myeloid Cells (TREM) Family Member, TLT-6, is Involved in Activation and Proliferation of Macrophages

The triggering receptor expressed on myeloid cells (TREM) family, which is abundantly expressed in myeloid lineage cells, plays a pivotal role in innate and adaptive immune response. In this study, we aimed to identify a novel receptor expressed on hematopoietic stem cells (HSCs) by using in silico bioinformatics and to characterize the identified receptor. We thus found the TREM-like transcript (TLT)-6, a new member of TREM family. TLT-6 has a single immunoglobulin domain in the extracellular region and a long cytoplasmic region containing 2 immunoreceptor tyrosine-based inhibitory motif-like domains. TLT-6 transcript was expressed in HSCs, monocytes and macrophages. TLT-6 protein was up-regulated on the surface of bone marrow-derived and peritoneal macrophages by lipopolysaccharide stimulation. TLT-6 exerted anti-proliferative effects in macrophages. Our results demonstrate that TLT-6 may regulate the activation and proliferation of macrophages.

Increased HoxB4 Inhibits Apoptotic Cell Death in Pro-B Cells

HoxB4, a homeodomain-containing transcription factor, is involved in the expansion of hematopoietic stem cells and progenitor cells in vivo and in vitro, and plays a key role in regulating the balance between hematopoietic stem cell renewal and cell differentiation. However, the biological activity of HoxB4 in other cells has not been reported. In this study, we investigated the effect of overexpressed HoxB4 on cell survival under various conditions that induce death, using the Ba/F3 cell line. Analysis of phenotypical characteristics showed that HoxB4 overexpression in Ba/F3 cells reduced cell size, death, and proliferation rate. Moreover, the progression from early to late apoptotic stages was inhibited in Ba/F3 cells subjected to HoxB4 overexpression under removal of interleukin-3-mediated signal, leading to the induction of cell cycle arrest at the G2/M phase and attenuated cell death by Fas protein stimulation in vitro. Furthermore, apoptotic cell death induced by doxorubicin-treated G2/M phase cell-cycle arrest also decreased with HoxB4 overexpression in Ba/F3 cells. From these data, we suggest that HoxB4 may play an important role in the regulation of pro-B cell survival under various apoptotic death environments.

Proteomic Analysis of Colonic Mucosal Tissue from Tuberculous and Ulcerative Colitis Patients

Changes in the expression profiles of specific proteins leads to serious human diseases, including colitis. The proteomic changes related to colitis and the differential expression between tuberculous (TC) and ulcerative colitis (UC) in colon tissue from colitis patients has not been defined. We therefore performed a proteomic analysis of human TC and UC mucosal tissue. Total protein was obtained from the colon mucosal tissue of normal, TC, and UC patients, and resolved by 2-dimensional electrophoresis (2-DE). The results were analyzed with PDQuest using silver staining. We used matrix-assisted laser desorption ionization time-of-flight/time-of-flight spectrometry (MALDI TOF/TOF) to identify proteins differentially expressed in TC and UC. Of the over 1,000 proteins isolated, three in TC tissue and two in UC tissue displayed altered expression when compared to normal tissue. Moreover, two proteins were differentially expressed in a comparative analysis between TC and UC. These were identified as mutant beta-actin, alpha-enolase and Charcot-Leyden crystal protein. In particular, the expression of alpha-enolase was significantly greater in TC compared with normal tissue, but decreased in comparison to UC, implying that alpha-enolase may represent a biomarker for differential diagnosis of TC and UC. This study therefore provides a valuable resource for the molecular and diagnostic analysis of human colitis.

Differential Expression of Proteins Related with Penile Apoptosis in a Rat after Cavernous Nerve Resection / 대한남성과학회지

PURPOSE: The mechanism including changes of proteome within cavernosal tissue after cavernous nerve injury were not evaluated. We performed proteomics and functional analysis to identify proteins of penile corpus cavernosum whose expression was or was not altered by cavernous nerve resection (CNR). MATERIALS AND METHODS: Using 8-week-old male WKY rats, sham and CNR operation under microscope were performed. After 8 weeks, penile tissues of sham and CNR group were harvested. We used 2-DE and MALDI-TOF/TOF (AB 4700) to identify of differently expressed penile proteins. 2-DE gels were stained with silver nitrate and the gels were analyzed with PDQuest. RESULTS: We isolated more than 950 proteins on silver-stained gels of whole protein extracts from normal rat penile corpus cavernous. Of these proteins, 48 prominent proteins were identified using MALDI-TOF/TOF. Protein characterization revealed that the most prominent penile corpus cavernous proteins were those with antioxidant, chaperone, or cytoskeletal structure. Moreover, 11 proteins having levels elevated by CNR were annexin proteins, endoplasmic reticulum protein 29, glutathione s-transferase w-1, and others. In addition, Rho-GDP dissociation inhibitor (RhoGDI), a regulator of Rho proteins, was also increased in CNR rats compared with sham-operated control rats. CONCLUSIONS: The apoptotic signals observed in penile tissues was greatly increased in CNR rats than in sham-operated rats. These results suggest that RhoGDI is one of the proteins regulated by CNR in penile smooth muscle strips, and has a crucial role in the early stage of penile apoptosis.

Tetrahydrobiopterin Inhibits PDGF-stimulated Migration and Proliferation in Rat Aortic Smooth Muscle Cells via the Nitric Oxide Synthase-independent Pathway

Tetrahydrobiopterin (BH4), an essential cofactor for nitric oxide synthase (NOS) activity, is known to play important roles in modulating both NO and superoxide production during vascular diseases such as atherosclerosis. However, the role of BH4 in functions of vascular smooth muscle cells is not fully known. In this study, we tested the effects of BH4 and dihydrobiopterin (BH2), a BH4 precursor, on migration and proliferation in response to platelet-derived growth factor-BB (PDGF-BB) in rat aortic smooth muscle cells (RASMCs). Cell migration and proliferation were measured using a Boyden chamber and a 5-bromo-2'-deoxyuridine incorporation assay, respectively, and these results were confirmed with an ex vivo aortic sprout assay. Cell viability was examined by 2,3-bis [2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide assays. BH4 and BH2 decreased PDGF-BB-induced cell migration and proliferation in a dose-dependent manner. The inhibition of cell migration and proliferation by BH4 and BH2 was not affected by pretreatment with N G-nitro-L-arginine methyl ester, a NOS inhibitor. Moreover, the sprout outgrowth formation of aortic rings induced by PDGF-BB was inhibited by BH4 and BH2. Cell viability was not inhibited by BH4 and BH2 treatment. The present results suggest that BH4 and BH2 may inhibit PDGF-stimulated RASMC migration and proliferation via the NOS-independent pathway. Therefore, BH4 and its derivative could be useful for the development of a candidate molecule with an NO-independent anti-atherosclerotic function.

Olibanum Extract Inhibits Vascular Smooth Muscle Cell Migration and Proliferation in Response to Platelet-Derived Growth Factor

Olibanum (Boswellia serrata) has been shown to have anti-inflammatory, anti-arthritic and anti- cancer effects. This study determined the role of a water extract of olibanum in platelet-derived growth factor (PDGF)-stimulated proliferation and migration of rat aortic smooth muscle cells (RASMCs). PDGF-BB induced the migration and proliferation of RASMCs that were inhibited by olibanum extract in a dose-dependent manner. The PDGF-BB-increased phosphorylation of p38 mitogen-activated protein kinase (MAPK); the heat shock protein (Hsp) 27 was significantly inhibited by the olibanum extract. The effects of PDGF-BB-induced extracellular signal-regulated kinase1/2 was not altered by the olibanum extract. Treatment with olibanum extract inhibited PDGF-BB-stimulated sprout out growth of aortic rings. These results suggest that the water extract of olibanum inhibits PDGF-BB-stimulated migration and proliferation in RASMCs as well as sprout out growth, which may be mediated by the inhibition of the p38 MAPK and Hsp27 pathways.

p38 MAPK Participates in Muscle-Specific RING Finger 1-Mediated Atrophy in Cast-Immobilized Rat Gastrocnemius Muscle

Skeletal muscle atrophy is a common phenomenon during the prolonged muscle disuse caused by cast immobilization, extended aging states, bed rest, space flight, or other factors. However, the cellular mechanisms of the atrophic process are poorly understood. In this study, we investigated the involvement of mitogen-activated protein kinase (MAPK) in the expression of muscle-specific RING finger 1 (MuRF1) during atrophy of the rat gastrocnemius muscle. Histological analysis revealed that cast immobilization induced the atrophy of the gastrocnemius muscle, with diminution of muscle weight and cross-sectional area after 14 days. Cast immobilization significantly elevated the expression of MuRF1 and the phosphorylation of p38 MAPK. The starvation of L6 rat skeletal myoblasts under serum-free conditions induced the phosphorylation of p38 MAPK and the characteristics typical of cast-immobilized gastrocnemius muscle. The expression of MuRF1 was also elevated in serum-starved L6 myoblasts, but was significantly attenuated by SB203580, an inhibitor of p38 MAPK. Changes in the sizes of L6 myoblasts in response to starvation were also reversed by their transfection with MuRF1 small interfering RNA or treatment with SB203580. From these results, we suggest that the expression of MuRF1 in cast-immobilized atrophy is regulated by p38 MAPK in rat gastrocnemius muscles.

Propofol Inhibits Platelet-derived Growth Factor-stimulated Migration in Rat Aortic Smooth Muscle Cells / 대한마취과학회지

BACKGROUND: Propofol is the extensively used general anesthetic-sedative agent.Although propofol is known to be involved in migration of various cells, migration response to it in vascular smooth muscle cells is not investigated. This study was carried out to determine the role of propofol in migration of rat aortic smooth muscle cells (RASMCs). METHODS: A7r5 RASMCs were used.Cell migration was examined by the analysis of 5 ng/ml of platelet-derived growth factor (PDGF)-induced RASMC response after treatment of cells with propofol (1-100micrometer) in the Boyden chamber.The activity of cofilin by propofol in RASMCs was measured by the Western blot analysis for the change of cofilin dephosphorylaton in cells treated with 10micrometer propofol for 5, 10, 15 and 20 min, for the effect of propofol (1, 10 and 100micrometer) on cofilin phosphorylation, and for the effects of ethylene glycol-bis (beta-aminoethyl ether)-N,N,N',N'-tetra acetic acid (2 mM; EGTA), Na3VO4 (200micrometer), and calyculin A (10 nM) on 10micrometer propofol-induced cofilin dephosphorylation. RESULTS: PDGF increased RASMC migration and this response was dose-dependently inhibited by treatment with propofol. Propofol attenuated the cofilin phosphorylation in RASMCs in a dose- and time-dependent manner.Propofol-induced dephosphorylation of cofilin in RASMCs was abolished by calyculin A, a protein phosphatase 2A inhibitor, but not by EGTA, a Ca2+ chelating agent, or Na3VO4, a protein tyrosine phosphatase inhibitor. CONCLUSIONS: The present results suggest that propofol induces the diminution of PDGF-stimulated RASMC migration and this response may be associated with dephosphorylation of cofilin mediated by the protein phosphatase 2A-dependent pathway.