Fibronectin provides a conduit for fibroblast transmigration from collagenous stroma into fibrin clot provisional matrix

1997 ◽  
Vol 110 (7) ◽  
pp. 861-870 ◽  
Author(s):  
D. Greiling ◽  
R.A. Clark

After injury, the wound space is filled with a fibrin/fibronectin clot containing growth factors released by platelets and monocytes. In response to these factors, fibroblasts migrate into the fibrin clot and contribute to the formation of granulation tissue. The functional mechanisms allowing fibroblasts to leave the collagenous matrix of normal connective tissue and invade the provisional matrix of the fibrin clot have not been fully defined. To investigate these mechanisms we established a new in vitro model which simulates specific aspects of early wound healing, that is, the migration of fibroblasts from a three-dimensional collagen matrix into a fibrin clot. This transmigration could be induced by physiological concentrations of platelet releasate or platelet-derived growth factor BB (PDGF-BB) in a concentration-dependent manner. At 24 hours irradiated fibroblasts invaded the fibrin gel almost as well as non-irradiated cells, indicating that transmigration was independent of proliferation. Plasminogen and its activators appear to be necessary for invasion of the fibrin clot since protease inhibitors decreased the amount of migration. These serine proteases, however, were not necessary for exit from the collagen gel as fibroblasts migrated out of the collagen gel onto a surface coated with fibrin fibrils even in the presence of inhibitors. Removal of fibronectin (FN) from either the collagen gel or the fibrin gel markedly decreased the number of migrating cells, suggesting that FN provides a conduit for transmigration. Cell movement in the in vitro model was inhibited by RGD peptide, and by monoclonal antibodies against the subunits of the alpha5 beta1 and alpha v beta3 integrin receptor. Thus, the functional requirements for fibroblast transmigration from collagen-rich to fibrin-rich matrices, such as occurs in early wound healing, have been partially defined using an in vitro paradigm of this important biologic process.

1997 ◽  
Vol 272 (1) ◽  
pp. G106-G115 ◽  
Author(s):  
F. G. Que ◽  
G. J. Gores ◽  
N. F. LaRusso

Although histological data suggest that cholangiocytes die by apoptosis in human liver diseases, no information exists on the mechanisms of cholangiocyte apoptosis. Thus our aims were to establish an in vitro model of cholangiocyte apoptosis and to test the hypothesis that changes in intracellular ions would cause apoptosis in cholangiocytes by a protease-sensitive pathway. A large number of proapoptotic agents were ineffective in inducing apoptosis in rat or human cholangiocytes in culture; in contrast, beauvericin, a K+ ionophore, caused apoptosis in both cell lines, despite their expression of Bcl-2. Although beauvericin decreased intracellular K+ and increased intracellular Ca2+, abolishing the K+ gradient did not prevent beauvericin-induced apoptosis; in contrast, omission of extracellular Ca2+ inhibited apoptosis by 42%. The interleukin-1 beta-converting enzyme (ICE) family protease inhibitor, Z-Val-Ala-Asp chloromethylketone, inhibited apoptosis in a concentration-dependent manner. By Northern blot analysis, cholangiocytes expressed the mRNA for three members of the ICE protease family: ICE, ICE/ CED-3 homologue-1 (ICH-1), and cysteine protease P-32 (CPP-32). Cleavage of a substrate for CPP-32-like protease activity, but not a substrate for ICE and ICH-1, increased after beauvericin treatment. In summary, we have established an in vitro model of apoptosis in cholangiocytes. Our data suggest that beauvericin-induced apoptosis occurs by a Ca(2+)-dependent CPP-32 protease-sensitive pathway despite cholangiocyte expression of Bcl-2.


Author(s):  
Hoda Keshmiri Neghab ◽  
Mohammad Hasan Soheilifar ◽  
Gholamreza Esmaeeli Djavid

Abstract. Wound healing consists of a series of highly orderly overlapping processes characterized by hemostasis, inflammation, proliferation, and remodeling. Prolongation or interruption in each phase can lead to delayed wound healing or a non-healing chronic wound. Vitamin A is a crucial nutrient that is most beneficial for the health of the skin. The present study was undertaken to determine the effect of vitamin A on regeneration, angiogenesis, and inflammation characteristics in an in vitro model system during wound healing. For this purpose, mouse skin normal fibroblast (L929), human umbilical vein endothelial cell (HUVEC), and monocyte/macrophage-like cell line (RAW 264.7) were considered to evaluate proliferation, angiogenesis, and anti-inflammatory responses, respectively. Vitamin A (0.1–5 μM) increased cellular proliferation of L929 and HUVEC (p < 0.05). Similarly, it stimulated angiogenesis by promoting endothelial cell migration up to approximately 4 fold and interestingly tube formation up to 8.5 fold (p < 0.01). Furthermore, vitamin A treatment was shown to decrease the level of nitric oxide production in a dose-dependent effect (p < 0.05), exhibiting the anti-inflammatory property of vitamin A in accelerating wound healing. These results may reveal the therapeutic potential of vitamin A in diabetic wound healing by stimulating regeneration, angiogenesis, and anti-inflammation responses.


2004 ◽  
Vol 12 (2) ◽  
pp. A26-A26
Author(s):  
F E Dhawahir ◽  
C Sheridan ◽  
D Kent ◽  
D Wong ◽  
I Grierson ◽  
...  

1991 ◽  
Vol 98 (3) ◽  
pp. 333-342
Author(s):  
R.S. Tuan ◽  
C.J. Moore ◽  
J.W. Brittingham ◽  
J.J. Kirwin ◽  
R.E. Akins ◽  
...  

During human fetal development, placental syncytiotrophoblasts actively transport calcium from the maternal to the fetal circulation. Two functional components, a cytosolic Ca2(+)-binding protein (CaBP) and a Ca2(+)-ATPase have been identified in the syncytiotrophoblasts of the chorionic villi. We report here the calcium uptake properties of a human choriocarcinoma cell line, JEG-3, which was used as an in vitro model cell system for the syncytiotrophoblasts. In culture, JEG-3 proliferated as large syncytial aggregates expressing typical syncytiotrophoblast markers. 45Ca uptake by JEG-3 was a substrate- and temperature-dependent, membrane-mediated active process that exhibited linear kinetics for up to 7 min. Both the CaBP and the Ca2(+)-ATPase were expressed by JEG-3, on the basis of biochemical, histochemical, immunochemical and or mRNA assays. Immunohistochemistry and in situ hybridization revealed that JEG-3 cells were heterogeneous with respect to the expression of the CaBP. The Ca2(+)-ATPase activity of JEG-3 was similar to the placental enzyme in terms of sensitivity to specific inhibitors, and was detected histochemically along the cell membrane. Fura-2 Ca2+ imaging revealed that calcium uptake by JEG-3 was not accompanied by a concomitant increase in cytosolic [Ca2+], suggesting a specific Ca2+ sequestration mechanism. The involvement of calciotropic hormonal regulation was evaluated by studying the response of JEG-3 to 1,25-dihydroxy vitamin D3. Calcium uptake was significantly stimulated in a dose-dependent manner by a 24-h treatment of the cells with 1,25-dihydroxy vitamin D3 (optimal dose approximately 0.5 nM); the CaBP level doubled whereas steady-state CaBP mRNA did not, suggesting that CaBP expression was regulated by 1,25-dihydroxy vitamin D3. These observations strongly suggest that the JEG-3 human choriocarcinoma cells should serve as a convenient in vitro model system for studying the cellular mechanism and regulation of transplacental calcium transport.


TH Open ◽  
2020 ◽  
Vol 04 (02) ◽  
pp. e94-e103
Author(s):  
Yanan Zong ◽  
Aleksandra Antovic ◽  
Nida Mahmoud Hourani Soutari ◽  
Jovan Antovic ◽  
Iva Pruner

AbstractDevelopment of inhibitors to factor VIII (FVIII) occurs in approximately 30% of severe hemophilia A (HA) patients. These patients are treated with bypassing agents (activated prothrombin complex concentrate [aPCC] and recombinant activated FVII-rFVIIa). Recently, a bispecific FIX/FIXa- and FX/FXa-directed antibody (emicizumab) has been approved for the treatment of HA patients with inhibitors. However, the data from clinical studies imply that coadministration of emicizumab and bypassing agents, especially aPCC, could have a thrombotic effect.This study was aimed to address the question of potential hypercoagulability of emicizumab and bypassing agents' coadministration, we have investigated fibrin clot formation and structure in the in vitro model of severe HA after adding sequence-identical analogue (SIA) of emicizumab and bypassing agents.Combined overall hemostasis potential (OHP) and fibrin clot turbidity assay was performed in FVIII-deficient plasma after addition of different concentrations of SIA, rFVIIa, and aPCC. Pooled normal plasma was used as control. The fibrin clots were analyzed by scanning electron microscopy (SEM).OHP and turbidity parameters improved with the addition of aPCC, while therapeutic concentrations of rFVIIa did not show substantial improvement. SIA alone and in combination with rFVIIa or low aPCC concentration improved OHP and turbidity parameters and stabilized fibrin network, while in combination with higher concentrations of aPCC expressed hypercoagulable pattern and generated denser clots.Our in vitro model suggests that combination of SIA and aPCC could potentially be prothrombotic, due to hypercoagulable changes in fibrin clot turbidity and morphology. Additionally, combination of SIA and rFVIIa leads to the formation of stable clots similar to normal fibrin clots.


2015 ◽  
Vol 27 (1) ◽  
pp. 199
Author(s):  
J.-H. Lee ◽  
E.-B. Jeung

The placenta exchanges vital factors, including oxygen, carbon dioxide, copper, iron, calcium cations, and glucose, which are essential to fetal growth. Each molecule is transferred by specific receptors that are located at the cell membrane or in the cytoplasm. Copper, iron, calcium cations, and glucose transfer genes are regulated by estrogens, vitamin D, and human placental lactogen. Regulations of these receptors depend on pregnancy time length and maternal and fetal nutrient environment with various pathways. Some synthetic plastics known as endocrine disrupting chemicals (EDC) have a similar structure to reproductive hormones such as estrogens. Thus, these substances have a potential effect on the expression of genes which are regulated by estrogens or progesterone by interfering their pathways. Having an estrogenic property, EDC interact with oestrogen receptors and elevate or decrease the expression of target genes which are responsible for transporting essential molecules such as copper, iron, and calcium. To examine the effects of EDC exposure during pregnancy, we conducted an in vitro model study using the BeWo human trophoblast cell line. The BeWo cell was treated with well-known EDC, octyl-phenol (OP), nonyl-phenol (NP), and bisphenol A (BPA) in a dose-dependent manner (10–7, 10–6, and 10–5 M) for 24 h. The expression of copper (CTR1, ATP7A), iron (IREG1, HEPH), and calcium transporting genes (PMCA1, TRPV6), were measured by real-time RT–PCR and Western blot. The expression of copper, iron, and calcium transporting genes were elevated in a dose-dependent manner by all well-known EDC, including OP, NP, and BPA, as well as E2. To unveil the mechanism of these elevations of ionic transporting genes, an ERE promoter study will be needed. Taken together, essential cation transporting genes in placenta are modulated by EDC.


2020 ◽  
Vol 8 (12) ◽  
pp. 2019
Author(s):  
Fernando Díaz-Yáñez ◽  
Ricardo Álvarez ◽  
Iván L. Calderón ◽  
Juan A. Fuentes ◽  
Fernando Gil

Salmonella Typhimurium is a facultative, intracellular pathogen whose products range from self-limited gastroenteritis to systemic diseases. Food ingestion increases biomolecules’ concentration in the intestinal lumen, including amino acids such as cysteine, which is toxic in a concentration-dependent manner. When cysteine’s intracellular concentration reaches toxic levels, S. Typhimurium expresses a cysteine-inducible enzyme (CdsH), which converts cysteine into pyruvate, sulfide, and ammonia. Despite this evidence, the biological context of cdsH’s role is not completely clear, especially in the infective cycle. Since inside epithelial cells both cdsH and its positive regulator, ybaO, are overexpressed, we hypothesized a possible role of cdsH in the intestinal phase of the infection. To test this hypothesis, we used an in vitro model of HT-29 cell infection, adding extra cysteine to the culture medium during the infective process. We observed that, at 6 h post-invasion, the wild type S. Typhimurium proliferated 30% more than the ΔcdsH strain in the presence of extra cysteine. This result shows that cdsH contributes to the bacterial replication in the intracellular environment in increased concentrations of extracellular cysteine, strongly suggesting that cdsH participates by increasing the bacterial fitness in the intestinal phase of the S. Typhimurium infection.


Pharmaceutics ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 1203
Author(s):  
May Wenche Jøraholmen ◽  
Mona Johannessen ◽  
Kirsten Gravningen ◽  
Mirja Puolakkainen ◽  
Ganesh Acharya ◽  
...  

Chlamydia trachomatis is the most common cause of bacterial sexually transmitted infections and causes serious reproductive tract complications among women. The limitations of existing oral antibiotics and treatment of antimicrobial resistance require alternative treatment options. We are proposing, for the first time, the natural polyphenol resveratrol (RES) in an advanced delivery system comprising liposomes incorporated in chitosan hydrogel, for the localized treatment of C. trachomatis infection. Both free RES and RES liposomes-in-hydrogel inhibited the propagation of C. trachomatis in a concentration-dependent manner, assessed by the commonly used in vitro model comprising McCoy cells. However, for lower concentrations, the anti-chlamydial effect of RES was enhanced when incorporated into a liposomes-in-hydrogel delivery system, with inhibition of 78% and 94% for 1.5 and 3 µg/mL RES, respectively for RES liposomes-in-hydrogel, compared to 43% and 72%, respectively, for free RES. Furthermore, RES liposomes-in-hydrogel exhibited strong anti-inflammatory activity in vitro, in a concentration-dependent inhibition of nitric oxide production in the LPS-induced macrophages (RAW 264.7). The combination of a natural substance exhibiting multi-targeted pharmacological properties, and a delivery system that provides enhanced activity as well as applicability for vaginal administration, could be a promising option for the localized treatment of C. trachomatis infection.


1991 ◽  
Vol 260 (2) ◽  
pp. G207-G212 ◽  
Author(s):  
A. R. Giuliano ◽  
R. J. Wood

The human colon adenocarcinoma cell line Caco-2 is the only intestinal cell line to differentiate spontaneously in culture exhibiting structural and biochemical characteristics of mature enterocytes and to possess a vitamin D receptor in the fully differentiated state. Transepithelial calcium transport was characterized in differentiated Caco-2 cells grown on permeable filters supports to assess the potential utility of this cell line as an in vitro model to study 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]-induced calcium transport. Calcium transport was increased in a dose-dependent manner by 1,25(OH)2D3. Total calcium transport at different calcium concentrations could be fitted to a modified Michaelis-Menten equation containing a linear transport component. The maximum rate of saturable calcium transport was increased by 4.3-fold (P less than 0.005) in cells treated with 10(-8) M 1,25(OH)2D3. This treatment also increased the apparent buffer calcium concentration that results in half-maximal velocity from 0.4 to 1.3 mM but had no significant effect on nonsaturable calcium transport. Caco-2 cells grown on permeable filter supports provide a unique in vitro human cell culture model to study the mechanism of vitamin D-regulated transepithelial intestinal calcium transport.


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