Mechanisms of recovery from mechanical injury of cultured rat hepatocytes

1996 ◽  
Vol 271 (3) ◽  
pp. C721-C727 ◽  
Author(s):  
H. T. Sponsel ◽  
P. S. Guzelian ◽  
S. E. Brown ◽  
R. Breckon ◽  
C. Ray ◽  
...  
Keyword(s):  
Growth Factors ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Primary Cultures ◽  
Rat Hepatocytes ◽  
Integrin Subunit ◽  
Hepatocyte Growth Factors ◽  
Beta 1 Integrin ◽  
Rate Of Recovery ◽  
Hepatocyte Growth

The mechanism(s) whereby hepatocytes restore denuded areas remains unknown. We therefore studied the recovery of denuded areas made in monolayers of primary cultures of rat hepatocytes. Minimal recovery occurred in cells plated on plastic. Plating on Matrigel produced modest recovery (25% at 24 h), whereas plating on a type I collagen substrate resulted in > 70% recovery at 24 h. The rate of recovery on collagen could be attenuated by a monoclonal antibody directed against the extracellular domain of the beta 1-integrin subunit. Monoclonal antibodies directed against CD44 (the hyaluron receptor) and E-cadherin did not influence the rate of recovery. Recovery could be stimulated, in a dose-dependent fashion, by epidermal and hepatocyte growth factors. The effects of epidermal and hepatocyte growth factors to promote recovery occurred in the absence of 5-bromo-2'-deoxyuridine uptake, suggesting a proliferation-independent mechanism. Transforming growth factor-beta 1 inhibited recovery. Exposure to selected cytokines (interleukins 1 and 2), an adenine nucleotide [adenosine 5'-O-(3-thiotriphosphate)], adenosine, pertussis toxin, and selected agents that bind to fibronectin and other matrix component adhesive sites (heparin and the RGD peptide) did not influence the rate of recovery of hepatocytes. However, the peptide DGEA, which can bind to collagen adhesive sites, attenuated recovery. These studies demonstrate that primary cultures of rat hepatocytes require a particular type of extracellular matrix to renew denuded areas and that the beta 1-integrin subunit may be involved in this recovery process. Hepatocyte recovery of denuded areas can be modulated by growth factors in both a stimulatory (epidermal and hepatocyte growth factors) and an inhibitory (transforming growth factor-beta 1) fashion.

scholarly journals Utilizing the ABC Transporter for Growth Factor Production by fleQ Deletion Mutant of Pseudomonas fluorescens

Biomedicines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 679
Author(s):  
Benedict-Uy Fabia ◽  
Joshua Bingwa ◽  
Jiyeon Park ◽  
Nguyen-Mihn Hieu ◽  
Jung-Hoon Ahn
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Pseudomonas Fluorescens ◽  
Abc Transporter ◽  
Transforming Growth Factor Beta ◽  
Deletion Mutant ◽  
Transforming Growth Factor ◽  
Gene Knockout ◽  
Type I ◽  
Double Deletion

Pseudomonas fluorescens, a gram-negative bacterium, has been proven to be a capable protein manufacturing factory (PMF). Utilizing its ATP-binding cassette (ABC) transporter, a type I secretion system, P. fluorescens has successfully produced recombinant proteins. However, besides the target proteins, P. fluorescens also secretes unnecessary background proteins that complicate protein purification and other downstream processes. One of the background proteins produced in large amounts is FliC, a flagellin protein. In this study, the master regulator of flagella gene expression, fleQ, was deleted from P. fluorescens Δtp, a lipase and protease double-deletion mutant, via targeted gene knockout. FleQ directs flagella synthesis, so the new strain, P. fluorescens ΔfleQ, does not produce flagella-related proteins. This not only simplifies purification but also makes P. fluorescens ΔfleQ an eco-friendly expression host because it will not survive outside a controlled environment. Six recombinant growth factors, namely, insulin-like growth factors I and II, beta-nerve growth factor, fibroblast growth factor 1, transforming growth factor beta, and tumor necrosis factor beta, prepared using our supercharging method, were successfully secreted by P. fluorescens ΔfleQ. Our findings demonstrate the potential of P. fluorescens ΔfleQ, combined with our supercharging process, as a PMF.

Mechanisms of renal tubular cell hypertrophy: mitogen-induced suppression of proteolysis

1997 ◽  
Vol 273 (3) ◽  
pp. C843-C851 ◽  
Author(s):  
H. A. Franch ◽  
P. V. Curtis ◽  
W. E. Mitch
Keyword(s):  
Protein Synthesis ◽  
Growth Factors ◽  
Growth Factor ◽  
Protein Degradation ◽  
Transforming Growth Factor ◽  
Primary Cultures ◽  
Renal Tubular Cell ◽  
Kidney Cells ◽  
Tgf Beta ◽  
Lysosomal Proteolysis

The combination of epidermal growth factor (EGF) plus transforming growth factor-beta 1 (TGF-beta 1) causes hypertrophy in renal epithelial cells. One mechanism contributing to hypertrophy is that EGF induces activation of the cell cycle and increases protein synthesis, whereas TGF-beta 1 prevents cell division, thereby converting hyperplasia to hypertrophy. To assess whether suppression of proteolysis is another mechanism causing hypertrophy induced by these growth factors, we measured protein degradation in primary cultures of proximal tubule cells and in cultured NRK-52E kidney cells. A concentration of 10(-8) M EGF alone or EGF plus 10(-10) M TGF-beta 1 decreased proteolysis by approximately 30%. TGF-beta 1 alone did not change protein degradation. Using inhibitors, we examined which proteolytic pathway is suppressed. Neither proteasome nor calpain inhibitors prevented the antiproteolytic response to EGF + TGF-beta 1. Inhibitors of lysosomal proteases eliminated the antiproteolytic response to EGF + TGF-beta 1, suggesting that these growth factors act to suppress lysosomal proteolysis. This antiproteolytic response was not caused by impaired EGF receptor signaling, since lysosomal inhibitors did not block EGF-induced protein synthesis. We conclude that suppression of lysosomal proteolysis contributes to growth factor-mediated hypertrophy of cultured kidney cells.

Abstract 165: Amp-activated Protein Kinase (ampk) α1 in Macrophages Promotes Collateral Remodeling and Arteriogenesis in Mice

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Huaiping Zhu
Keyword(s):  
Growth Factors ◽  
Transforming Growth Factor Beta ◽  
Hind Limb ◽  
Transforming Growth Factor ◽  
Arterial Occlusion ◽  
Arterial Stenosis ◽  
Surrounding Tissue ◽  
Chronic Coronary Occlusion ◽  
Collateral Arteries ◽  
Collateral Vessels

Efficient arteriogenesis is vital for recovery after cardiovascular events (such as chronic coronary occlusion, myocardial infarction). Identifying the biological factors that affect arteriogenesis will help design new treatments for patients with chronic arterial stenosis and occlusions. Circulating monocytes and macrophages recruited within the surrounding tissue of collateral vessels following arterial occlusion have been reported to be essential to arteriogenesis in collateral arteries/arterioles because they promote the proliferation of vascular smooth muscle cells (VSMCs) and endothelial cells through secreted cytokines. Although a growing number of putative arteriogenic factors have been identified, the exact mechanisms that regulate collateral remodeling have remained largely unknown. Here we report that AMPK, an energy and redox sensor, is required for monocyte-mediated collateral remodeling. Collateral arteriogenesis was monitored in WT, global AMPKα1 knockout (KO), or macrophage-specific AMPKα1 KO mice with or without hind limb ligation. Compared to WT mice with ligation, global AMPKα1 KO mice displayed significant reduction in blood flow recovery and impaired remodeling of collateral arterioles. Similar impairments were observed in macrophage-specific AMPK α1 KO mice following hind limb ligation. Mechanistically, we found that AMPKα1 promotes the production of growth factors, such as transforming growth factor beta, by directly phosphorylating the inhibitor of nuclear factor kappa B (NF-κB) kinase alpha, resulting in an NF-κB-dependent production of growth factors. Collectively, our findings suggest a novel role for macrophage AMPKα1 in arteriogenesis and collateral remodeling and indicate that AMPKα1 activation might be a therapeutic target for treating occlusive vascular disorders.

Regulation of mesenchymal extracellular matrix protein synthesis by transforming growth factor-beta and glucocorticoids in tumor stroma

1995 ◽  
Vol 108 (6) ◽  
pp. 2153-2162 ◽  
Author(s):  
J.F. Talts ◽  
A. Weller ◽  
R. Timpl ◽  
M. Ekblom ◽  
P. Ekblom
Keyword(s):  
Extracellular Matrix ◽  
Growth Factors ◽  
Growth Factor ◽  
Mrna Expression ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Tenascin C ◽  
Extracellular Matrix Components ◽  
Growth Factor Beta ◽  
Matrix Components

We have here studied the composition and regulation of stromal extracellular matrix components in an experimental tumor model. Nude mice were inoculated with WCCS-1 cells, a human Wilms' tumor cell line. In the formed tumors the stroma was found to contain mesenchymal extracellular matrix proteins such as tenascin-C, fibulins-1 and 2 and fibronectin, but no nidogen. Nidogen was confined to basement membranes of tumor blood vessels. Since glucocorticoids have been shown to downregulate tenascin-C expression in vitro, we tested whether dexamethasone can influence biosynthesis of extracellular matrix components during tumor formation in vivo. A downregulation of tenascin-C mRNA and an upregulation of fibronectin mRNA expression by dexamethasone was noted. Transforming growth factor-beta 1 mRNA levels were unaffected by the dexamethasone treatment. Glucocorticoids can thus downregulate tenascin-C synthesis although local stimulatory growth factors are present. The competition between a negative and a positive extrinsic factor on synthesis of stromal extracellular matrix components was studied in a fibroblast/preadipocyte cell line. Transforming growth factor-beta 1 stimulated tenascin-C synthesis but did not affect fibronectin or fibulin-2 synthesis. Dexamethasone at high concentrations could completely suppress the effect of transforming growth factor-beta 1 on tenascin-C mRNA expression. Transforming growth factor-beta 1 could in turn overcome the downregulation of tenascin-C mRNA expression caused by a lower concentration of dexamethasone. We therefore suggest that the limited expression of tenascin-C in part is due to a continuous suppression by physiological levels of glucocorticoids, which can be overcome by local stimulatory growth factors when present in sufficient amounts.

scholarly journals Medicinal Leech CNS as a Model for Exosome Studies in the Crosstalk between Microglia and Neurons

2018 ◽  
Vol 19 (12) ◽  
pp. 4124 ◽  
Author(s):  
Antonella Raffo-Romero ◽  
Tanina Arab ◽  
Issa Al-Amri ◽  
Francoise Le Marrec-Croq ◽  
Christelle Van Camp ◽  
...  
Keyword(s):  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Ex Vivo ◽  
Present Report ◽  
Primary Cultures ◽  
Cell Communication ◽  
Medicinal Leech ◽  
Neuronal Cultures ◽  
Primary Neuronal Cultures ◽  
A Cell

In healthy or pathological brains, the neuroinflammatory state is supported by a strong communication involving microglia and neurons. Recent studies indicate that extracellular vesicles (EVs), including exosomes and microvesicles, play a key role in the physiological interactions between cells allowing central nervous system (CNS) development and/or integrity. The present report used medicinal leech CNS to investigate microglia/neuron crosstalk from ex vivo approaches as well as primary cultures. The results demonstrated a large production of exosomes from microglia. Their incubation to primary neuronal cultures showed a strong interaction with neurites. In addition, neurite outgrowth assays demonstrated microglia exosomes to exhibit significant neurotrophic activities using at least a Transforming Growth Factor beta (TGF-β) family member, called nGDF (nervous Growth/Differentiation Factor). Of interest, the results also showed an EV-mediated dialog between leech microglia and rat cells highlighting this communication to be more a matter of molecules than of species. Taken together, the present report brings a new insight into the microglia/neuron crosstalk in CNS and would help deciphering the molecular evolution of such a cell communication in brain.

Growth factors and metanephrogenesis

1992 ◽  
Vol 262 (4) ◽  
pp. F523-F532 ◽  
Author(s):  
M. R. Hammerman ◽  
S. A. Rogers ◽  
G. Ryan
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Transforming Growth Factor Beta ◽  
Kidney Development ◽  
Transforming Growth Factor ◽  
Polypeptide Growth Factors ◽  
Metanephric Kidney ◽  
Epidermal Growth ◽  
Factor Alpha ◽  
Editorial Review

The formation of all organs during embryogenesis, including kidney, is dependent on the timed and sequential expression of a number of polypeptide growth factors. Synthesis and actions of one or more members of the insulin-like growth factor, epidermal growth factor/transforming growth factor-alpha, transforming growth factor-beta, platelet-derived growth factor, fibroblast growth factor, and nerve growth factor families have been characterized in the developing metanephric kidney. Studies originating from a number of laboratories have defined the localization of growth factor mRNAs, receptors and peptides, have delineated patterns of growth factor synthesis, and have established the growth factor dependency of embryonic kidney development. The results of these investigations will be summarized in this editorial review and integrated within the broader context of growth factor cellular physiology and growth factor expression in nonrenal systems.

scholarly journals Gene expression of growth factor BMP15, GDF9, FGF2 and their receptors in bovine follicular cells

2018 ◽  
pp. 6778-6787 ◽  
Author(s):  
Pablo S Reineri ◽  
María S. Coria ◽  
María G. Barrionuevo ◽  
Olegario Hernández ◽  
Santiago Callejas ◽  
...  
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Growth Factor Receptor ◽  
Follicular Development ◽  
Fibroblast Growth ◽  
Rt Pcr ◽  
Follicular Cells

Introduction. Growth and follicular maturation involve transformations of various components of the follicle, such as the oocyte, granulosa and techa cells. Several growth factors, including differentiation growth factor 9 (GDF9), bone morphogenic protein 15 (BMP15) and basic fibroblast growth factor (FGF2) are important for follicular development and oocyte maturation, by its ability to increase the proliferation of granulosa, techa cells and the ovarian stroma. Objetive. Evaluate mRNA expression of GDF9, BMP15, FGF2 and their main receptors, transforming growth factor beta receptor 1 (TGFβ-R1), bone morphogenetic protein receptor, type IB (BMPR-IB) and fibroblast growth factor receptor 2 (FGFR2) in bovine follicular cells. Materials and methods. Total RNA was isolated from pooled samples of oocytes (OOs), cumulus cells (CCs) of cumulus oocyte complexes (COCs) and follicular cell pellets (PCs) of 70 ovaries obtained from 96 beef heifers, collected at a local abattoir. The expression pattern of growth factors and their receptors in follicular bovine cells was evaluated by reverse transcriptase polymerase chain reaction (RT-PCR). Results. The mRNA transcripts encoding GDF9, BMP15, FGF2, TGFβ-R1, BMPR-IB and FGFR2 genes were detected, by RT-PCR, in all studied cells. This is the first time that the expression of TGFβ-R1 and BMPR-IB receptors is reported in bovine oocytes. Conclusions. The presence of growth factors and receptor transcripts in the studied cells indicate that these factors could act as paracrine and autocrine regulators of folliculogenesis.

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