Stimulation of fibroblast collagen and total protein formation by an endothelial cell-derived factor

Pterostilbene accelerates wound healing response in diabetic mice through Nrf2 regulation

Pterostilbene (PTS), known for its diverse beneficial effects via Nuclear factor erythroid-2 related factor (Nrf2) activation, holds potential for Diabetic Foot Ulcer (DFU) treatment. However, PTS-mediated Nrf2 regulation in diabetic wounds has yet to be elucidated. We used IC21 macrophage-conditioned media to simulate complex events that can influence the fibroblast phenotype using L929 cells during the wound healing process under a hyperglycemic microenvironment. We found that PTS attenuated fibroblast migration and alpha-smooth muscle actin (α-SMA) levels and hypoxia-inducible factor- 1 alpha (HIF1α). Furthermore, we demonstrated that wounds in diabetic mice characterized by impaired wound closure in a heightened inflammatory milieu, such as the NOD-like receptor P3 (NLRP3) and intercellular adhesion molecule 1 (ICAM1), and deficient Nrf2 response accompanying lowered Akt signaling and heme oxygenase1 (HO1) expression along with the impaired macrophage M2 marker CD206 expression, was rescued by administration of PTS. Such an elicited response was also compared favorably with the standard treatment using Regranex, a commercially available topical formulation for treating DFUs. Our findings suggest that PTS regulates Nrf2 in diabetic wounds, triggering a pro-wound healing response mediated by macrophages. This insight holds the potential for developing targeted therapies to heal chronic wounds, including DFUs.

The Advances in Glioblastoma On-a-Chip for Therapy Approaches

Simple Summary

This systematic review showed different therapeutic approaches to glioblastoma on-a-chip with varying levels of complexity, answering, from the simplest question to the most sophisticated questions, in a biological system integrated in an efficient way. With advances in manufacturing protocols, soft lithography in PDMS material was the most used in the studies, applying different strategy geometrics in device construction. The microenvironment showed the relevant elaborations in co-culture between mainly human tumor cells and support cells involved in the collagen type I matrix; remaining an adequate way to assess the therapeutic approach. The most complex devices showed efficient intersection between different systems, allowing in vitro studies with major human genetic similarity, reproducibility, and low cost, on a highly customizable platform.

Abstract

This systematic review aimed to verify the use of microfluidic devices in the process of implementing and evaluating the effectiveness of therapeutic approaches in glioblastoma on-a-chip, providing a broad view of advances to date in the use of this technology and their perspectives. We searched studies with the variations of the keywords “Glioblastoma”, “microfluidic devices”, “organ-on-a-chip” and “therapy” of the last ten years in PubMed and Scopus databases. Of 446 articles identified, only 22 articles were selected for analysis according to the inclusion and exclusion criteria. The microfluidic devices were mainly produced by soft lithography technology, using the PDMS material (72%). In the microenvironment, the main extracellular matrix used was collagen type I. Most studies used U87-MG glioblastoma cells from humans and 31.8% were co-cultivated with HUVEC, hCMEC/D3, and astrocytes. Chemotherapy was the majority of therapeutic approaches, assessing mainly the cellular viability and proliferation. Furthermore, some alternative therapies were reported in a few studies (22.6%). This study identified a diversity of glioblastoma on-a-chip to assess therapeutic approaches, often using intermediate levels of complexity. The most advanced level implemented the intersection between different biological systems (liver–brain or intestine–liver–brain), BBB model, allowing in vitro studies with greater human genetic similarity, reproducibility, and low cost, in a highly customizable platform.

Wound healing potential of human umbilical cord mesenchymal stem cell conditioned medium: An in vitro and in vivo study in diabetes-induced rats

Background and Aim:

Human umbilical cord mesenchymal stem cells (hUC-MSCs) and its conditioned medium (CM) promote wound healing. This study investigated the wound healing potential of hUC-MSC CM in vitro and in vivo using diabetic animal models.

Materials and Methods:

The CM from hUC-MSC CM prepared under hypoxic conditions (hypoxic hUC-MSC) was evaluated for stimulating rat fibroblast growth, collagen production (in vitro), and wound healing in animal models (in vivo). An excision wound on the dorsal side of the diabetes-induced rats was established, and the rats were randomly divided into non-treatment, antibiotic, and hypoxic hUC-MSC CM groups. The cell number of fibroblasts and collagen secretion was evaluated and compared among the groups in an in vitro study. By contrast, wound size reduction, width of re-epithelialization, and the collagen formation area were assessed and compared among the groups in an in vivo study.

Results:

CM under hypoxic conditions contained a higher concentration of wound healing-related growth factors. Hypoxic hUC-MSC CM could facilitate fibroblast cell growth and collagen synthesis, although not significant compared with the control group. Re-epithelialization and collagen production were higher in the hUC-MSC CM group than in the antibiotic and non-treatment groups.

Conclusion:

Hypoxic hUC-MSC CM possessed more positive effects on the wound healing process based on re-epithelialization and collagen formation than antibiotic treatment did.

Therapeutic Potential of Umbilical Cord Mesenchymal Stem Cells for Inhibiting Myofibroblastic Differentiation of Irradiated Human Lung Fibroblasts

Radiation-induced lung injury (RILI) limits the benefits of radiotherapy in patients with lung cancer. Radiation-induced differentiation of lung fibroblasts to myofibroblasts plays a key role in RILI. Recent studies have shown that mesenchymal stem cells (MSCs) can protect against lung fibrosis and that Wnt/β-catenin signaling is involved in fibrotic processes. In the present study, we explored the therapeutic potential of human umbilical cord MSCs (HUMSCs) for preventing radiation-induced differentiation of human lung fibroblasts (HLFs) to myofibroblasts. There are two advantages in the use of HUMSCs; namely, they are easily obtained and have low immunogenicity. Irradiated HLFs were co-cultured with HUMSCs. Expression of α-smooth muscle actin (α-SMA), a myofibroblast marker, was measured by Western blot analysis and immunohistochemistry. Irradiation (X-rays, 5 Gy) induced the differentiation of HLFs into myofibroblasts, which was inhibited by co-culture with HUMSCs. Irradiation also caused activation of the canonical Wnt/β-catenin signaling in HLFs, as judged by increased phosphorylation of glycogen synthase kinase 3β, nuclear accumulation of β-catenin, and elevated levels of Wnt-inducible signaling protein-1 (WISP-1) in the conditioned medium. However, co-culture with HUMSCs attenuated the radiation-induced activation of the Wnt/β-catenin signaling. We also measured the expression of FRAT1 that can enhance the Wnt/β-catenin signaling by stabilizing β-catenin. Co-culture with HUMSCs decreased FRAT1 protein levels in irradiated nHLFs. Thus, co-culture with HUMSCs attenuated the radiation-induced activation of Wnt/β-catenin signaling in HLFs, thereby inhibiting myofibroblastic differentiation of HLFs. Wnt/β-catenin signaling is a potential therapeutic target for limiting RILI in patients receiving radiotherapy for lung cancer.

The extracellular matrix is a novel attribute of endothelial progenitors and of hypoxic mature endothelial cells

Extracellular matrix (ECM) production is critical to preserve the function and integrity of mature blood vessels. Toward the engineering of blood vessels, studies have centered on ECM production by supporting cells, whereas few studies implicate endothelial cells (ECs) with ECM synthesis. Here, we elucidate variations between cultured human arterial, venous, and progenitor ECs with respect to ECM deposition assembly, composition, and response to biomolecular and physiological factors. Our studies reveal that progenitor ECs, endothelial colony-forming cells (ECFCs), deposit collagen IV, fibronectin, and laminin that assemble to an organized weblike structure, as confirmed by decellularized cultures. Mature ECs only express these ECM proteins intracellularly. ECFC-derived ECM is abrogated in response to TGFβ signaling inhibition and actin cytoskeleton disruption. Hypoxic (1%) and physiological (5%) O(2) tension stimulate ECM deposition from mature ECs. Interestingly, deposition of collagen I is observed only under 5% O(2) tension. ECM production from all ECs is found to be regulated by hypoxia-inducible factors 1α and 2α but differentially in the different cell lines. Collectively, we suggest that ECM deposition and assembly by ECs is dependent on maturation stage and oxygen supply and that these findings can be harnessed to advance engineered vascular therapeutics.

Mesenchymal stem cells produce Wnt isoforms and TGF-beta1 that mediate proliferation and procollagen expression by lung fibroblasts

Studies have been carried out previously to determine whether mesenchymal stem cells (MSC) influence the progression of pulmonary fibrosis. Here, we asked whether MSC (derived from mouse bone marrow and human umbilical cord blood) produce factors that mediate lung fibroblast (LF) growth and matrix production. MSC-conditioned media (CM) were found by ELISA to contain significant amounts of PDGF-AA and transforming growth factor-beta1 (TGF-beta1). Proliferation was increased in a concentration-dependent manner in LF cell lines and primary cells cultured in MSC-CM, but neither anti-PDGF antibodies nor PDGF receptor-specific antibodies affected proliferation, nor did a number of other antibodies to well-known mitogenic factors. However, proliferation was significantly inhibited by the Wnt signaling antagonist, secreted frizzled related protein-1 (sFRP-1). In addition, anti-Wnt1 and anti-Wnt2 antibodies attenuated MSC-CM-induced proliferation, and increased expression of Wnt7b was identified. As would be expected in cells activated by Wnt, nuclear beta-catenin was increased. The amount of TGF-beta1 in MSC-CM and its biological activity were revealed by activation at acidic pH. The stem cells synthesized and released TGF-beta1 that increased alpha1-procollagen gene expression by LF target cells. Addition of anti-TGF-beta to the MSC-CM blocked upregulation of collagen gene expression. These data demonstrate that MSC from mice and humans produce Wnt proteins and TGF-beta1 that respectively stimulate LF proliferation and matrix production, two hallmarks of fibroproliferative lung disease. It will be essential to determine whether these factors can play a role in attempts to use MSC for therapeutic approaches.

Treatment with TNF-alpha or bacterial lipopolysaccharide attenuates endocardial endothelial cell-mediated stimulation of cardiac fibroblasts

Background

The endocardial endothelium that lines the inner cavity of the heart is distinct from the microvascular endothelial cells and modulates cardiac muscle performance in a manner similar to the vascular endothelial modulation of vascular structure and vasomotor tone. Although the modulatory effects of endocardial endothelium (EE) on cardiomyocytes are firmly established, the regulatory effects of endocardial endothelium on the cardiac interstitium and its cellular components remain ill defined.

Methods and Results

We investigated whether the stimulatory effect of EE on cardiac fibroblasts would be altered when EECs are activated by the cytokine tumor necrosis factor-α (TNF-α) or the endotoxin bacterial lipopolysaccharide (LPS). Both TNF-α and LPS were found to independently attenuate the stimulatory effect of EE on cardiac fibroblasts. These agents lowered the synthesis or release of ET-1 and increased the secretion of TGF-β and NO.

Conclusion

The findings of this study using endocardial endothelial cells (EECs) and neonatal cardiac fibroblasts demonstrate that pro-inflammatory cytokines cause altered secretion of paracrine factors by EECs and inhibit proliferation and lower collagen synthesis in fibroblasts. These changes may influence fibroblast response and extra cellular matrix remodeling in pathological conditions of the heart.

Endocardial endothelial cells stimulate proliferation and collagen synthesis of cardiac fibroblasts

Given that vascular endothelial cells play an important role in the modulation of vascular structure and function, we hypothesized that endocardial endothelial cells (EECs) may have a modulator role in regulating the cardiac interstitial cells. Endocardial endothelial cells were isolated from freshly collected pig hearts and cardiac fibroblasts were isolated from 3- to 4-d-old Wistar rats. Fibroblasts were cultured in the presence or absence of conditioned medium from EECs. Proliferation of cardiac fibroblasts was measured by the incorporation of [3H]- Thymidine and collagen synthesis was assayed by the incorporation of [3H]-Proline. To determine the involvement of signaling mediators, in separate experiments, cardiac fibroblasts were incubated with BQ123 (selective ETA receptor antagonist), PD142893 (nonselective ETA/ETB receptor antagonist), Bis-indolylmaleimide (PKC inhibitor), PD 098059 (MEK inhibitor), or neutralizing anti-transforming growth factor (TGF)-beta-antibody. Endocardial endothelium-derived factors endothelin (ET)-1, TGF-beta, and Angiotensin (Ang)-II in the conditioned medium were assayed by enzyme-linked immunosorbent assay using commercially available kits. We report here evidence that suggest that endocardial endothelial cells stimulate both proliferation and collagen synthesis of cardiac fibroblasts. The response seems to be mediated by endothelin through its ETA receptor. Our results also indicate that protein kinase C (PKC) and mitogen-activated protein kinase (MAPK) pathways are essential for the EEC-induced proliferation of cardiac fibroblasts.

Cardiac myofibroblasts isolated from the site of myocardial infarction express endothelin de novo

Recently it was demonstrated that treatment with a nonselective endothelin (ET) receptor antagonist significantly reduces myocardial infarct size, which suggests a major role for ET in tissue repair following myocardial infarction (MI). Tissue repair and remodeling found at the site of MI are mainly attributed to myofibroblasts (myoFbs), which are phenotypically transformed fibroblasts that express alpha-smooth muscle actin. It is unclear whether myoFbs generate ET peptides and consequentially regulate pathophysiological functions de novo through expression of the ET-1 precursor (prepro-ET-1), ET-converting enzyme-1 (ECE-1), a metalloprotease that is required to convert Big ET-1 to ET-1 and ET receptors. To address these intriguing questions, we used cultured myoFbs isolated from 4-wk-old MI scar tissue. In cultured cells, we found: 1) expression of mRNA for ET precursor gene (ppET1), ECE-1, and ETA and ETB receptors by semiquantitative RT-PCR; 2) phosphoramidon-sensitive ECE-1 activity, which converts Big ET-1 to biologically active peptide ET-1; 3) expression of ETA and ETB receptors; 4) elaboration of Big ET-1 and ET-1 peptides in myoFb culture media; and 5) upregulation of type I collagen gene expression and synthesis by ET, which was blocked by bosentan (a nonselective ETA- and ETB receptor blocker). These studies clearly indicated that myoFbs express and generate ET-1 and receptor-mediated modulation of type I collagen expression by ET-1. Locally generated ET-1 may contribute to tissue repair of the infarcted heart in an autocrine/paracrine manner.

Collagen synthesis and collagenase activity of cryopreserved heart valves

OBJECTIVE

Durability of the valve seems to be dependent on the remodeling ability of the valve itself, which is controlled by both collagen synthesis and collagenolytic activity of valvular fibroblasts and endothelial cells. However, the balance of collagen synthesis and collagenolysis of the cryopreserved valve has not yet been clearly revealed. Thus, we assessed the collagen synthesis and collagenolysis ability of the cryopreserved valve.

METHODS

Twelve valves were divided into 2 groups: freshly harvested valves (n = 6) and cryopreserved valves (n = 6). We measured the collagen content using Sirius red, a dye selective to the collagen. Collagen synthesis was evaluated by means of the tritiated proline incorporation method. Noncollagenase-digestible counts, which represent protein synthesis, and collagenase-digestible counts, which represent collagen synthesis, were estimated. Collagenase activity of the valves was assessed by gelatin zymography.

RESULTS

The collagen content of the cryopreserved group was maintained. The noncollagenase-digestible counts of the cryopreserved group decreased from 3862 +/- 1180 counts/mg to 1174 +/- 1362 counts/mg, and the collagenase-digestible counts of the cryopreserved group were 831 +/- 762 counts/mg compared with the value of 1062 +/- 136 counts/mg for the freshly harvested group. The collagenase activity of the cryopreserved group was observed at the same level as that of the freshly harvested group, despite the serious endothelial damage of the cryopreserved valves.

CONCLUSIONS

Although the collagen synthesis of cryopreserved valves was relatively maintained, the protein synthesis was highly diminished, and the collagenolysis ability was activated immediately after the thawing process. These results imply that the cryopreservation procedure itself may cause the collagen metabolism to be on the degradable side, which will lead to valve failure.

Des-Arg(10)-kallidin engagement of the B1 receptor stimulates type I collagen synthesis via stabilization of connective tissue growth factor mRNA

Expression of the kinin B1 receptor is up-regulated in chronic inflammatory and fibrotic disorders; however, little is known about its role in fibrogenesis. We examined human embryonic lung fibroblasts that constitutively express the B1 receptor and report that engagement of the B1 receptor by des-Arg(10)-kallidin stabilized connective tissue growth factor (CTGF) mRNA, stimulated an increase in alpha1(I) collagen mRNA, and stimulated type I collagen production. These events were not observed in B2 receptor-activated fibroblasts. In addition, B1 receptor activation by des-Arg(10)-kallidin induced a rise in cytosolic Ca(2+) that is consistent with B1 receptor pharmacology. Our results show that the des-Arg(10)-kallidin-stimulated increase in alpha1(I) collagen mRNA was time- and dose-dependent, with a peak response observed at 20 h with 100 nM des-Arg(10)-kallidin. The increase in CTGF mRNA was also time- and dose-dependent, with a peak response observed at 4 h with 100 nM des-Arg(10)-kallidin. The increase in CTGF mRNA was blocked by the B1 receptor antagonist des-Arg(10),Leu(9)-kallidin. Inhibition of protein synthesis by cycloheximide did not block the des-Arg(10)-kallidin-induced increase in CTGF mRNA. These results suggest that engagement of the kinin B1 receptor contributes to fibrogenesis through increased expression of CTGF.

The pathogenesis of cutaneous fibrosis

Cutaneous fibrosis is an integral component of a variety of human disorders including keloids, hypertrophic scar, and most notably, scleroderma. Each has its own etiology and unique clinical characteristics, but all involve the dysregulation of connective tissue metabolism, in particular, the activation of dermal fibroblasts. In this review, we examine various molecular events in scleroderma that may lead to fibroblast activation, and propose a new model to explain the persistence of such activation by scleroderma fibroblasts in the apparent absence of exogenous stimuli.

Induction of cell proliferation and collagen synthesis in human small intestinal lamina propria fibroblasts by lipopolysaccharide: possible involvement of nitric oxide

Recent studies suggest that tissue specific fibroblasts respond to inflammatory stimuli leading to the onset of inflammatory disorders. In the present study, we investigated cell kinetics, collagen synthesis, and nitric oxide (NO) level in cultured human small intestinal lamina propria fibroblasts (HSILPF, n = 45) in response to LPS of enteropathogenic E. coli. LPS treatment enhanced the 3[H] TdR uptake, increased the percentage of 'S' phase cells as early as 4 hrs, and decreased the population doubling time of HSILPF in a dose and time dependent manner. Collagen synthesis in HSILPF was also elevated by LPS. The LPS induced cell proliferation and collagen synthesis were inhibited by polymyxin B (10 micrograms/ml). LPS was found to suppress the NO production in these cells, whereas combination of LPS (10 micrograms/ml) and IFN gamma (100 U/ml) enhanced NO output and concurrently decreased the cell proliferation and collagen production in HSILPF. Inhibitors of NO, L-NG-monomethyl L-arginine, and aminoguanidine partially restored cell proliferation and collagen synthesis in cells exposed to LPS and IFN gamma. These findings suggest that LPS induces increased cell proliferation and collagen synthesis in HSILPF and these could be related to the suppression of NO production.

Induction of tissue inhibitor and matrix metalloproteinase by serum in human heart-derived fibroblast and endomyocardial endothelial cells

To understand the regulatory mechanisms of extracellular matrix (ECM) turnover and proteinase expression in human cardiovascular tissue, we have isolated and characterized human heart fibroblast (HHF) and human heart endothelial (HHE) cells from endomyocardial biopsy specimens. HHE cell in culture exhibited the typical cobblestone growth pattern and positive immunofluorescent staining for factor VIII related antigen. HHF demonstrated the typical spindle shape during culture and were positive for vimentin. Both cell types were negative for alpha-actin, indicating that these cells were of nonmuscle origin. Cell growth studies revealed significant growth when maintained in limiting serum concentration, suggesting mitogenic activity of these cells, and demonstrated growth inhibitory activity when grown in serum-free medium. Serum-dependent matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) expression was measured by zymography, immunoblot, and Northern blot analysis. Results indicated that serum induces both the MMP and TIMP expression at the mRNA and protein levels in a dose-dependent manner. This induction was inhibited by actinomycin D and cycloheximide, suggesting transcriptional and translational regulation of MMP and TIMP. Indirect immunofluorescence labeling indicated expression of MMP and TIMP in HHF and HHE cells. These results suggested that the serum induces proliferation as well as expression of MMP and TIMP in HHE and HHF cells. The growth inhibitory activity of these cell cultures will enable us to explore further the nature of this response and compare this phenomenon with other growth inhibitors and growth promoters identified in other normal and transformed cells.

Characterization of a fibroblast cell from the urinary bladder wall

For the first time we report on the growth, culture, and matrix production characteristics of a cell type isolated from the lamina propria of the urinary bladder wall. A fibroblastlike cell was identified as distinct from bladder detrusor smooth muscle cells and urothelium based on morphology, growth characteristics, and immunohistochemical staining. Characterization of extracellular matrix synthesis by this cell type using 35S-methionine metabolic labeling demonstrated that these cells are capable of secreting components of the surrounding connective tissue, including several fibrillar collagens, a basement membrane collagen, and fibronectin.

Left ventricular dysfunction in ischemic heart disease: fundamental importance of the fibrous matrix

The contractile function of the myocardium is coordinated by a fibrous matrix of exquisite organization and complexity. In the normal heart, and apparently in physiological hypertrophy, this matrix is submicroscopic. In pathological states changes are frequent, and usually progressive. Thickening of the many elements of the fine structure is due to an increased synthesis of Type I collagen, This change, which affects the myocardium in a global manner, can be observed by light microscopy using special techniques. Perivascular fibrosis, with an increase in vascular smooth muscle, is accompanied by development of fibrous septa, with a decrease in diastolic compliance. These structural changes are believed to be due to increased activation of the renin-angiotensin-aldosterone system, and to be independent of the processes of myocyte hypertrophy. Reparative or replacement fibrosis is a separate process by means of which small and large areas of necrosis heal, with the development of coarse collagen structures, which lack a specific organizational pattern. Regarding ischemic heart disease, an increase in tissue collagenase is found in experimental myocardial "stunning" and in the very early phase of acute infarction. Absence of elements of the fibrous matrix allow for myocyte slippage, and--if the affected area is large--cardiac dilatation. If, subsequently, the necrosis becomes transmural, there is further disturbance of collagen due to both mechanical strain and continued autolysis, During healing collagen synthesis increases greatly to allow for reparative scarring in the available tissue matrix. In cases of infarction with moderate or severe initial dilatation, pathological hypertrophy of the spared myocardium is progressive, accounting for late heart failure and poor survival.(ABSTRACT TRUNCATED AT 250 WORDS)

Endothelial cell replication in an in vivo model of aortic allografts

Previous studies of aortic valve allograft viability have used in vitro assessments that may not reflect in vivo properties. This study evaluated in vivo endothelial cell replication in experimental valved aortic grafts and examined the consequences of histoincompatibility and cryopreservation. Valved aortic conduits were heterotopically transplanted into syngeneic or allogeneic rats. Tritiated thymidine was administered to graft recipients and control rats. After 72 hours, monolayers from the native aortas and the aortic portion of the grafts were prepared for autoradiography, with six or more silver grains per nucleus considered evidence of replication. Percentages of replicating cells in native aortas ranged from 0.3% to 2.3% (p = not significant). Percentages of replicating cells in the fresh isografts (12.4%) and allografts (12.2%) were not significantly different from each other, although each was significantly greater than the percentage in its native aorta (p < 0.04). Cryopreserved allografts and isografts displayed a few endothelial cells, none of which was replicating. Immunologic differences do not affect endothelial cell replication in this early period after fresh graft transplantation. Cryopreservation, however, results in the absence of replicating endothelium.