Molecular and mechano-biology of collagen gel contraction mediated by human MG-63 cells: involvement of specific intracellular signaling pathways and the cytoskeleton

2009 ◽  
Vol 87 (6) ◽  
pp. 895-904 ◽  
Author(s):  
Justin Parreno ◽  
David A. Hart
Keyword(s):  
Signaling Pathways ◽  
Intracellular Signaling ◽  
Potential Role ◽  
Collagen Gel ◽  
Protein Kinase Inhibitors ◽  
Intrinsic Stress ◽  
Mrna Levels ◽  
Collagen Gels ◽  
Collagen Gel Contraction

Culture of human osteoblast-like MG-63 cells within collagen gels results in the generation of intrinsic stress. Release of such collagen gels from attachment results in gel contraction and enhanced MMP-1, MMP-3, and α2 integrin mRNA levels. To understand the potential role of microtubules and signaling pathways involved in MG-63 cell-mediated contraction and gene expression, cells were cultured in collagen gels. After 24 h collagen gels were released, then immediately treated with nocodazole or specific protein kinase inhibitors. Contraction was assessed, RNA isolated, and real-time PCR analysis performed. Treatment with high concentrations of a microtubule depolymerization agent, nocodazole, enhanced early contraction and led to elevated mRNA levels for MMP-3, whereas low concentrations inhibited contraction at later time points and did not affect mRNA levels. ROCK inhibitor treatment (Y27632) inhibited collagen gel contraction and led to depressed mRNA levels. The ERK1/2 inhibitor U0126 did not affect contraction, but treatment led to depressed MMP-1, MMP-3, and α2 mRNA levels. The p38MAPK inhibitor SB203580 modestly affected contraction, but did not affect mRNA levels. These results suggest the potential role of cytoskeletal integrity and multiple kinase signaling pathways in specific bone-remodeling events.

Tetracycline-Based MMP Inhibitors Can Prevent Fibroblast-Mediated Collagen Gel Contraction In Vitro

1998 ◽  
Vol 12 (1) ◽  
pp. 86-93 ◽  
Author(s):  
S.A. Myers ◽  
R.G. Wolowacz
Keyword(s):  
Culture Media ◽  
Collagen Gel ◽  
Collagen Gels ◽  
Cytotoxic Effects ◽  
Chemically Modified ◽  
Tissue Culture Media ◽  
Collagen Gel Contraction ◽  
Chemically Modified Tetracyclines

Collagen gels in vitro can be contracted by fibroblasts. The role of matrix metalloproteinases (MMPs) in the contraction of collagen lattices by human neonatal foreskin fibroblasts (HuFFs) was investigated in tissue culture media supplemented by various doses of known gelatinase inhibitors. Fluorescent assays with model gelatinase substrates and media conditioned by fibroblasts apparently confirmed the ability of chemically modified tetracyclines (CMTs) to act as inhibitors of MMP2, and zymography demonstrated that this was the major cell-derived MMP activity. There were no observable effects on the rate of contraction of attached FPCLs containing 6 x 104 HuFFs (passages 18-25) with either CMT-5 or CMT-2 at all concentrations tested (0-100 μg/mL). However, at greater than 20 μg/mL doxycycline and greater than 5 μg/mL CMT-3, FPCL contraction was completely abolished. Quantitative assessment of cell viability by means of the MTT assay in monolayer and qualitatively within the FPCLs with CalceinAM suggested that differences were not due to cytotoxic effects. Seeding FPCLs with lower-passage fibroblasts produced identical trends. These results may implicate the involvement of MMPs in the process of gel contraction, although tetracyclines have effects additional to their ability to inhibit MMPs directly.

Constitutive RNA synthesis for the yeast activator ADR1 and identification of the ADR1-5c mutation: implications in posttranslational control of ADR1

1986 ◽  
Vol 6 (11) ◽  
pp. 4026-4030
Author(s):  
C L Denis ◽  
C Gallo
Keyword(s):  
Rna Synthesis ◽  
Potential Role ◽  
Glucose Repression ◽  
Posttranslational Regulation ◽  
Mrna Levels ◽  
Recognition Sequence ◽  
Dependent Protein Kinase ◽  
Dependent Protein ◽  
Kinase Phosphorylation

The regulation of mRNA production for the yeast positive activator ADR1, a gene required for the expression of the glucose-repressible alcohol dehydrogenase (ADH II), was studied. ADR1 mRNA levels did not vary when yeasts were switched from glucose- to ethanol-containing medium, while ADH II expression increased 100-fold. The mRNA for the ADR1-5c allele, which augments ADH II expression 60-fold during glucose repression, was not present in greater abundance than ADR1 mRNA. Additionally, the ccr1-1 allele, which blocks ADH2 mRNA formation and partially suppresses the ADR1-5c phenotype, did not alter the levels of ADR1 mRNA. These results indicate that ADR1 is not transcriptionally controlled. To determine the character of the ADR1-5c mutation, the region containing the mutation was identified and sequenced. At base pair +683 a G-to-A transition was detected in the ADR1 coding sequence which would result in the substitution of a lysine residue for an arginine at amino acid 228. The location of the ADR1-5c mutation in the interior of the ADR1 coding sequences suggests that it enhances the activity of an extant but inactive ADR1 protein rather than increases the abundance of ADR1 by altered translation of its mRNA. The ADR1-5c mutation occurs in a region of the polypeptide corresponding to a cyclic AMP-dependent protein kinase phosphorylation recognition sequence. The potential role of reversible phosphorylation in the posttranslational regulation of ADR1 is discussed.

The balance between p53 isoforms modulates the efficiency of HIV-1 infection in macrophages

2021 ◽  
Author(s):  
Yann Breton ◽  
Corinne Barat ◽  
Michel J. Tremblay
Keyword(s):  
Virus Replication ◽  
Potential Role ◽  
Host Factors ◽  
Fine Tuning ◽  
Mrna Levels ◽  
Cellular Environment ◽  
P53 Isoforms ◽  
Antiviral Role ◽  
Hiv 1

Several host factors influence HIV-1 infection and replication. The p53-mediated antiviral role in monocytes-derived macrophages (MDMs) was previously highlighted. Indeed, an increase in p53 level results in a stronger restriction against HIV-1 early replication steps through SAMHD1 activity. In this study, we investigated the potential role of some p53 isoforms in HIV-1 infection. Transfection of isoform-specific siRNA induces distinctive effects on the virus life cycle. For example, in contrast to a siRNA targeting all isoforms, a knockdown of Δ133p53 transcripts reduces virus replication in MDMs that is correlated with a decrease in phosphorylated inactive SAMHD1. Combination of Δ133p53 knockdown and Nutlin-3, a pharmacological inhibitor of MDM2 that stabilizes p53, further reduces susceptibility of MDMs to HIV-1 infection, thus suggesting an inhibitory role of Δ133p53 towards p53 antiviral activity. In contrast, p53β knockdown in MDMs increases the viral production independently of SAMHD1. Moreover, experiments with a Nef-deficient virus show that this viral protein plays a protective role against the antiviral environment mediated by p53. Finally, HIV-1 infection affects the expression pattern of p53 isoforms by increasing p53β and p53γ mRNA levels while stabilizing the protein level of p53α and some isoforms from the p53β subclass. The balance between the various p53 isoforms is therefore an important factor in the overall susceptibility of macrophages to HIV-1 infection, fine-tuning the p53 response against HIV-1. This study brings a new understanding of the complex role of p53 in virus replication processes in myeloid cells. Importance As of today, HIV-1 is still considered as a global pandemic without a functional cure, partly because of the presence of stable viral reservoirs. Macrophages constitute one of these cell reservoirs, contributing to the viral persistence. Studies investigating the host factors involved in cell susceptibility to HIV-1 infection might lead to a better understanding of the reservoir formation and will eventually allow the development of an efficient cure. Our team previously showed the antiviral role of p53 in macrophages, which acts by compromising the early steps of HIV-1 replication. In this study, we demonstrate the involvement of p53 isoforms, which regulates p53 activity and define the cellular environment influencing viral replication. In addition, the results concerning the potential role of p53 in antiviral innate immunity could be transposed to other fields of virology and suggest that knowledge in oncology can be applied to HIV-1 research.

scholarly journals Constitutive RNA synthesis for the yeast activator ADR1 and identification of the ADR1-5c mutation: implications in posttranslational control of ADR1.

1986 ◽  
Vol 6 (11) ◽  
pp. 4026-4030 ◽  
Author(s):  
C L Denis ◽  
C Gallo
Keyword(s):  
Rna Synthesis ◽  
Potential Role ◽  
Glucose Repression ◽  
Posttranslational Regulation ◽  
Mrna Levels ◽  
Recognition Sequence ◽  
Dependent Protein Kinase ◽  
Dependent Protein ◽  
Kinase Phosphorylation

The regulation of mRNA production for the yeast positive activator ADR1, a gene required for the expression of the glucose-repressible alcohol dehydrogenase (ADH II), was studied. ADR1 mRNA levels did not vary when yeasts were switched from glucose- to ethanol-containing medium, while ADH II expression increased 100-fold. The mRNA for the ADR1-5c allele, which augments ADH II expression 60-fold during glucose repression, was not present in greater abundance than ADR1 mRNA. Additionally, the ccr1-1 allele, which blocks ADH2 mRNA formation and partially suppresses the ADR1-5c phenotype, did not alter the levels of ADR1 mRNA. These results indicate that ADR1 is not transcriptionally controlled. To determine the character of the ADR1-5c mutation, the region containing the mutation was identified and sequenced. At base pair +683 a G-to-A transition was detected in the ADR1 coding sequence which would result in the substitution of a lysine residue for an arginine at amino acid 228. The location of the ADR1-5c mutation in the interior of the ADR1 coding sequences suggests that it enhances the activity of an extant but inactive ADR1 protein rather than increases the abundance of ADR1 by altered translation of its mRNA. The ADR1-5c mutation occurs in a region of the polypeptide corresponding to a cyclic AMP-dependent protein kinase phosphorylation recognition sequence. The potential role of reversible phosphorylation in the posttranslational regulation of ADR1 is discussed.

Potential Role of Hyaluronic Acid on Bone in Osteoarthritis: Matrix Metalloproteinases, Aggrecanases, and RANKL Expression are Partially Prevented by Hyaluronic Acid in Interleukin 1-stimulated Osteoblasts

2014 ◽  
Vol 41 (5) ◽  
pp. 945-954 ◽  
Author(s):  
Zvezdana Mladenovic ◽  
Anne-Sophie Saurel ◽  
Francis Berenbaum ◽  
Claire Jacques
Keyword(s):  
Hyaluronic Acid ◽  
Matrix Metalloproteinases ◽  
Potential Role ◽  
Proteolytic Enzymes ◽  
Interleukin 1 ◽  
Nuclear Factor Κb ◽  
Mrna Levels ◽  
Receptor Activator ◽  
Polymerase Chain

Objective.To determine the effect of hyaluronic acid (HA) on proteolytic enzymes and bone remodeling mediators induced by interleukin 1β (IL-1β) and related to cartilage catabolism in murine osteoblasts.Methods.Osteoblasts were obtained from Swiss mice and cultured for 3 weeks. HA-treated osteoblasts were incubated with 100 μg/ml HA during the last week of culture, then stimulated with IL-1β (10 ng/ml) for 24 h. The expression of matrix metalloproteinases 3 and 13 (MMP-3 and MMP-13), ADAMTS-4 and ADAMTS-5, tissue inhibitor of metalloproteinases (TIMP), osteoprotegerin, and receptor activator of nuclear factor-κB ligand (RANKL) was determined by real-time polymerase chain reaction. MMP-3 and MMP-13 release was assessed by Western blot analysis.Results.IL-1β increased the mRNA levels of MMP-3 and MMP-13 and ADAMTS-4 and ADAMTS-5 and release of MMP-3 and MMP-13. Seven days of HA treatment significantly prevented the IL-1β-increased mRNA levels of MMP-3 (−61%, p < 0.01), MMP-13 (−56%, p < 0.01), ADAMTS-4 (−58%, p < 0.05), ADAMTS-5 (−52%, p < 0.01), and RANKL (−49%, p < 0.05), but not TIMP. As well, IL-1β-induced production of MMP-3 and MMP-13 was inhibited, by 27% (p < 0.01) and 40% (p < 0.01), respectively.Conclusion.In an inflammatory context in murine osteoblasts, HA can inhibit the expression of MMP and ADAMTS. Because HA can counteract the production of these mediators in chondrocytes, its beneficial effect in osteoarthritis may be due to its action on cartilage and subchondral bone.

scholarly journals The Role of Phosphotyrosine Signaling Pathway in Parotid Gland Proliferation and Function

1995 ◽  
Vol 6 (2) ◽  
pp. 119-131 ◽  
Author(s):  
K.R. Purushotham ◽  
M.G. Humphreys-Beher
Keyword(s):  
Salivary Glands ◽  
Tyrosine Kinases ◽  
Intracellular Signaling ◽  
Potential Role ◽  
Biological Processes ◽  
Secretory Function ◽  
Phosphotyrosine Signaling ◽  
And Function ◽  
Active Proliferation

Tyrosine phosphorylation and the intracellular signaling processes associated with it have been the focus of intense study due to its importance in the regulation of biological processes as diverse as cell proliferation and cell differentiation. While much of what we now understand has been derived from the study of cell lines and tumor cells, the salivary glands provide a model to examine the effects of tyrosine kinases and tyrosine phosphatases in a normal differentiated tissue. This review will focus, therefore, on the role tyrosine kinases and phosphatases play in inducing the transition from stasis to active proliferation and their potential role in mediating secretory function of the salivary glands.

scholarly journals Pathological processes and therapeutic advances in radioiodide refractory thyroid cancer

2017 ◽  
Vol 59 (4) ◽  
pp. R141-R154 ◽  
Author(s):  
Marika H Tesselaar ◽  
Johannes W Smit ◽  
James Nagarajah ◽  
Romana T Netea-Maier ◽  
Theo S Plantinga
Keyword(s):  
Thyroid Cancer ◽  
Signaling Pathways ◽  
Intracellular Signaling ◽  
Medullary Thyroid Cancer ◽  
Disease Remission ◽  
Intracellular Signaling Pathways ◽  
Oncogenic Mutations ◽  
Diagnostics And Therapy ◽  
Disease Present

While in most patients with non-medullary thyroid cancer (TC), disease remission is achieved by thyroidectomy and ablation of tumor remnants by radioactive iodide (RAI), a substantial subgroup of patients with metastatic disease present tumor lesions that have acquired RAI resistance as a result of dedifferentiation. Although oncogenic mutations inBRAF,TERTpromoter andTP53are associated with an increased propensity for induction of dedifferentiation, the role of genetic and epigenetic aberrations and their effects on important intracellular signaling pathways is not yet fully elucidated. Also immune, metabolic, stemness and microRNA pathways have emerged as important determinants of TC dedifferentiation and RAI resistance. These signaling pathways have major clinical implications since their targeting could inhibit TC progression and could enable redifferentiation to restore RAI sensitivity. In this review, we discuss the current insights into the pathological processes conferring dedifferentiation and RAI resistance in TC and elaborate on novel advances in diagnostics and therapy to improve the clinical outcome of RAI-refractory TC patients.

Sign in / Sign up

Export Citation Format

Share Document