scholarly journals Arcanobacterium pyogenes: Virulence factors, importance in mastitis etiology and therapeutic (im)possibilities

2011 ◽  
Vol 65 (3-4) ◽  
pp. 235-246
Author(s):  
Dubravka Milanov ◽  
Jelena Petrovic ◽  
Milos Kapetanov ◽  
Ljiljana Suvajdzic
Keyword(s):  
Extracellular Matrix ◽  
Virulence Factors ◽  
Opportunistic Pathogen ◽  
Clinical Mastitis ◽  
Livestock Species ◽  
Arcanobacterium Pyogenes ◽  
Possible Cause

Arcanobacterium pyogenes is an opportunistic pathogen, a causative agent of suppurative infections of organs and tissues in economically important livestock species. Most frequently this bacteria is isolated from inflamed lung lesions in pigs and cattle, in samples of uterine mucus of cows with endometritis and milk from cows with clinical mastitis. A. pyogenes possesses a number of virulence factors: cholesterol-dependent cytolysin (pyolysin), two neuraminidases, several proteases, extracellular matrix-binding proteins, DNases, fimbriae. The virulence factors are well studied in laboratory conditions, but the role of these factors in the pathogenesis of A. pyogenes infections remains to be elucidated. Lately, the ability of A. pyogenes to form biofilm in vivo has also been implicated as a virulence factor and a possible cause of therapeutic failure. Despite the fact that A. pyogenes milk isolates in cows with mastitis in vitro are very sensitive to ?-lactam drugs and tetracycline, experience has shown that therapy is usually ineffective, prognosis is poor and the affected quarter is lost for milk production.

scholarly journals The phosphatase Shp1 interacts with and dephosphorylates cortactin to inhibit invadopodia function

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Alessia Varone ◽  
Chiara Amoruso ◽  
Marcello Monti ◽  
Manpreet Patheja ◽  
Adelaide Greco ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Tyrosine Phosphatase ◽  
Melanoma Cells ◽  
Matrix Degradation ◽  
Extracellular Matrix Degradation ◽  
Invadopodia Formation ◽  
Interference Rna

Abstract Background Invadopodia are actin-based cell-membrane protrusions associated with the extracellular matrix degradation accompanying cancer invasion. The elucidation of the molecular mechanisms leading to invadopodia formation and activity is central for the prevention of tumor spreading and growth. Protein tyrosine kinases such as Src are known to regulate invadopodia assembly, little is however known on the role of protein tyrosine phosphatases in this process. Among these enzymes, we have selected the tyrosine phosphatase Shp1 to investigate its potential role in invadopodia assembly, due to its involvement in cancer development. Methods Co-immunoprecipitation and immunofluorescence studies were employed to identify novel substrate/s of Shp1AQ controlling invadopodia activity. The phosphorylation level of cortactin, the Shp1 substrate identified in this study, was assessed by immunoprecipitation, in vitro phosphatase and western blot assays. Short interference RNA and a catalytically-dead mutant of Shp1 expressed in A375MM melanoma cells were used to evaluate the role of the specific Shp1-mediated dephosphorylation of cortactin. The anti-invasive proprieties of glycerophosphoinositol, that directly binds and regulates Shp1, were investigated by extracellular matrix degradation assays and in vivo mouse model of metastasis. Results The data show that Shp1 was recruited to invadopodia and promoted the dephosphorylation of cortactin at tyrosine 421, leading to an attenuated capacity of melanoma cancer cells to degrade the extracellular matrix. Controls included the use of short interference RNA and catalytically-dead mutant that prevented the dephosphorylation of cortactin and hence the decrease the extracellular matrix degradation by melanoma cells. In addition, the phosphoinositide metabolite glycerophosphoinositol facilitated the localization of Shp1 at invadopodia hence promoting cortactin dephosphorylation. This impaired invadopodia function and tumor dissemination both in vitro and in an in vivo model of melanomas. Conclusion The main finding here reported is that cortactin is a specific substrate of the tyrosine phosphatase Shp1 and that its phosphorylation/dephosphorylation affects invadopodia formation and, as a consequence, the ability of melanoma cells to invade the extracellular matrix. Shp1 can thus be considered as a regulator of melanoma cell invasiveness and a potential target for antimetastatic drugs.

The extracellular matrix of the developing cornea: diversity, deposition and function*

Development ◽  
1988 ◽  
Vol 103 (Supplement) ◽  
pp. 195-205
Author(s):  
J. B. L. Bard ◽  
M. K. Bansal ◽  
A. S. A. Ross
Keyword(s):  
Extracellular Matrix ◽  
Chondroitin Sulphate ◽  
Corneal Stroma ◽  
Experimental System ◽  
Collagen I ◽  
And Function ◽  
20 Nm

This paper examines the role of the extracellular matrix (ECM) in the development of the cornea. After a brief summary of the corneal structure and ECM, we describe evidence suggesting that the differentiation of neural crest (NC) cells into endothelium and fibroblasts is under the control of ocular ECM. We then examine the role of collagen I in stromal morphogenesis by comparing normal corneas with those of homozygous Movl3 mice which do not make collagen I. We report that, in spite of this absence, the cellular morphology of the Movl3 eye is indistinguishable from that of the wild type. In the 16-day mutant stroma, however, the remaining collagens form small amounts of disorganized, thin fibrils rather than orthogonally organized 20 nm-diameter fibrils; a result implying that collagen I plays only a structural role and that its absence is not compensated for. It also suggests that, because these remaining collagens will not form the normal fibrils that they will in vitro, fibrillogenesis in the corneal stroma differs from that elsewhere. The latter part of the paper describes our current work on chick stromal deposition using corneal epithelia isolated with an intact basal lamina that lay down in vitro ∼3μm-thick stromas of organized fibrils similar to that seen in vivo. This experimental system has yielded two unexpected results. First, the amount of collagen and proteoglycans produced by such epithelia is not dependent on whether its substratum is collagenous and we therefore conclude that stromal production by the intact epithelium is more autonomous than hitherto thought. Second, chondroitin sulphate (CS), the predominant proteoglycan, appears to play no role in stromal morphogenesis: epithelia cultured in testicular hyaluronidase, which degrades CS, lay down stromas whose organization and fibrildiameter distribution are indistinguishable from controls. One possible role for CS, however, is as a lubricant which facilitates corneal growth: it could allow fibrils to move over one another without deforming their orthogonal organization. Finally, we have examined the processes of fibrillogenesis in the corneal stroma and conclude that they are different from those elsewhere in the embryo and in vitro, perhaps because there is in the primary stroma an unidentified, highly hydrated ECM macromolecule that embeds the fibrils and that may mediate their morphogenesis.

scholarly journals Hyaluronic acid-functionalized gelatin hydrogels reveal extracellular matrix signals temper the efficacy of erlotinib against patient-derived glioblastoma specimens

2019 ◽  
Author(s):  
Sara Pedron ◽  
Gabrielle L. Wolter ◽  
Jee-Wei E. Chen ◽  
Sarah E. Laken ◽  
Jann N. Sarkaria ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Hyaluronic Acid ◽  
Tumor Microenvironment ◽  
Kinase Inhibitor ◽  
Egfr Mutations ◽  
Primary Glioblastoma ◽  
Stat3 Phosphorylation

AbstractTherapeutic options to treat primary glioblastoma (GBM) tumors are scarce. GBM tumors with epidermal growth factor receptor (EGFR) mutations, in particular a constitutively active EGFRvIII mutant, have extremely poor clinical outcomes. GBM tumors with concurrent EGFR amplification and active phosphatase and tensin homolog (PTEN) are sensitive to the tyrosine kinase inhibitor erlotinib, but the effect is not durable. A persistent challenge to improved treatment is the poorly understood role of cellular, metabolic, and biophysical signals from the GBM tumor microenvironment on therapeutic efficacy and acquired resistance. The intractable nature of studying GBM cell in vivo motivates tissue engineering approaches to replicate aspects of the complex GBM tumor microenvironment. Here, we profile the effect of erlotinib on two patient-derived GBM specimens: EGFR+ GBM12 and EGFRvIII GBM6. We use a three-dimensional gelatin hydrogel to present brain-mimetic hyaluronic acid (HA) and evaluate the coordinated influence of extracellular matrix signals and EGFR mutation status on GBM cell migration, survival and proliferation, as well as signaling pathway activation in response to cyclic erlotinib exposure. Comparable to results observed in vivo for xenograft tumors, erlotinib exposure is not cytotoxic for GBM6 EGFRvIII specimens. We also identify a role of extracellular HA (via CD44) in altering the effect of erlotinib in GBM EGFR+ cells by modifying STAT3 phosphorylation status. Taken together, we report an in vitro tissue engineered platform to monitor signaling associated with poor response to targeted inhibitors in GBM.

scholarly journals Propionibacterium (Cutibacterium) granulosum Extracellular DNase BmdE Targeting Propionibacterium (Cutibacterium) acnes Biofilm Matrix, a Novel Inter-Species Competition Mechanism

2022 ◽  
Vol 11 ◽  
Author(s):  
Vicky Bronnec ◽  
Hinnerk Eilers ◽  
Anika C. Jahns ◽  
Hélène Omer ◽  
Oleg A. Alexeyev
Keyword(s):  
Extracellular Matrix ◽  
Acne Vulgaris ◽  
Opportunistic Pathogen ◽  
Resistant Bacteria ◽  
Skin Microbiome ◽  
Cutibacterium Acnes ◽  
Propionibacterium Granulosum ◽  
Extracellular Nuclease

Acne vulgaris is the most common dermatological disorder worldwide affecting more than 80% of adolescents and young adults with a global prevalence of 231 million cases in 2019. The involvement of the skin microbiome disbalance in the pathophysiology of acne is recognized, especially regarding the relative abundance and diversity of Propionibacterium acnes a well-known dominant human skin commensal. Biofilms, where bacteria are embedded into a protective polymeric extracellular matrix, are the most prevalent life style for microorganisms. P. acnes and its biofilm-forming ability is believed to be a contributing factor in the development of acne vulgaris, the persistence of the opportunistic pathogen and antibiotic therapy failures. Degradation of the extracellular matrix is one of the strategies used by bacteria to disperse the biofilm of competitors. In this study, we report the identification of an endogenous extracellular nuclease, BmdE, secreted by Propionibacterium granulosum able to degrade P. acnes biofilm both in vivo and in vitro. This, to our knowledge, may represent a novel competitive mechanism between two closely related species in the skin. Antibiotics targeting P. acnes have been the mainstay in acne treatment. Extensive and long-term use of antibiotics has led to the selection and spread of resistant bacteria. The extracellular DNase BmdE may represent a new bio-therapeutical strategy to combat P. acnes biofilm in acne vulgaris.

scholarly journals Function of BriC Peptide in the Pneumococcal Competence and Virulence Portfolio

2018 ◽  
Author(s):  
Surya D. Aggarwal ◽  
Rory Eutsey ◽  
Jacob West-Roberts ◽  
Arnau Domenech ◽  
Wenjie Xu ◽  
...  
Keyword(s):  
Murine Model ◽  
Biofilm Formation ◽  
Opportunistic Pathogen ◽  
Nasopharyngeal Colonization ◽  
Point Of Entry ◽  
Abiotic Surfaces ◽  
Biofilm Development

AbstractStreptococcus pneumoniae (pneumococcus) is an opportunistic pathogen that causes otitis media, sinusitis, pneumonia, meningitis and sepsis. The progression to this pathogenic lifestyle is preceded by asymptomatic colonization of the nasopharynx. This colonization is associated with biofilm formation; the competence pathway influences the structure and stability of biofilms. However, the molecules that link the competence pathway to biofilm formation are unknown. Here, we describe a new competence-induced gene, called briC, and demonstrate that its product promotes biofilm development and stimulates colonization in a murine model. We show that expression of briC is induced by the master regulator of competence, ComE. Whereas briC does not substantially influence early biofilm development on abiotic surfaces, it significantly impacts later stages of biofilm development. Specifically, briC expression leads to increases in biofilm biomass and thickness at 72h. Consistent with the role of biofilms in colonization, briC promotes nasopharyngeal colonization in the murine model. The function of BriC appears to be conserved across pneumococci, as comparative genomics reveal that briC is widespread across isolates. Surprisingly, many isolates, including strains from clinically important PMEN1 and PMEN14 lineages, which are widely associated with colonization, encode a long briC promoter. This long form captures an instance of genomic plasticity and functions as a competence-independent expression enhancer that may serve as a precocious point of entry into this otherwise competence-regulated pathway. Moreover, overexpression of briC by the long promoter fully rescues the comE-deletion induced biofilm defect in vitro, and partially in vivo. These findings indicate that BriC may bypass the influence of competence in biofilm development and that such a pathway may be active in a subset of pneumococcal lineages. In conclusion, BriC is a part of the complex molecular network that connects signaling of the competence pathway to biofilm development and colonization.

scholarly journals Extracellular Matrix and Integrins in Embryonic Stem Cell Differentiation

2015 ◽  
Vol 8s2 ◽  
pp. BCI.S30377 ◽  
Author(s):  
Han Wang ◽  
Xie Luo ◽  
Jake Leighton
Keyword(s):  
Extracellular Matrix ◽  
Pancreatic Beta Cells ◽  
Embryonic Stem ◽  
Stem Cell Differentiation ◽  
Embryonic Stem Cell Differentiation ◽  
In Vitro Differentiation ◽  
Integrin Receptors

Embryonic stem cells (ESCs) are pluripotent cells with great therapeutic potentials. The in vitro differentiation of ESC was designed by recapitulating embryogenesis. Significant progress has been made to improve the in vitro differentiation protocols by toning soluble maintenance factors. However, more robust methods for lineage-specific differentiation and maturation are still under development. Considering the complexity of in vivo embryogenesis environment, extracellular matrix (ECM) cues should be considered besides growth factor cues. ECM proteins bind to cells and act as ligands of integrin receptors on cell surfaces. Here, we summarize the role of the ECM and integrins in the formation of three germ layer progenies. Various ECM–integrin interactions were found, facilitating differentiation toward definitive endoderm, hepatocyte-like cells, pancreatic beta cells, early mesodermal progenitors, cardiomyocytes, neuroectoderm lineages, and epidermal cells, such as keratinocytes and melanocytes. In the future, ECM combinations for the optimal ESC differentiation environment will require substantial study.

Enhanced β-Catenin/Foxo1 Activity Alleviates Pulmonary Fibrosis by Inhibiting β-Catenin/T Cell Factor Signaling

2020 ◽  
Vol 10 (2) ◽  
pp. 182-188
Author(s):  
Kun Gui ◽  
Yu Huang ◽  
Meijin Wang ◽  
Jun Yang
Keyword(s):  
Extracellular Matrix ◽  
Pulmonary Fibrosis ◽  
Inflammatory Cytokines ◽  
Underlying Mechanism ◽  
Control Group ◽  
Kidney Fibrosis ◽  
Mrc5 Cell

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive fibrosing interstitial pneumonia, resulting in chronic respiratoryfailure and eventually death. β-catenin/Foxo1 showed a protective property in kidney fibrosis, but the role of β-catenin/Foxo1 in IPF was unclear. Our study aimed to investigate the role of β-catenin/Foxo1 in IPF and explore its underlying mechanism. The IPF model was established by injection of bleomycin (BLM) in vivo and stimulation by TGF-β1 in MRC5 cell in vitro. Haematoxylin-eosin staining and Masson’s trichrome staining were performed to examine histopathological injury in lung. Protein expression of corresponding genes was detected using western blot. Immunofluorescence staining assay was carried out to detect the expression of β-catenin, Foxo1, TCF and α-SMA. The expression levels of inflammatory cytokines were determined using ELISA kit assay. The results showed that BLM induced a serious pulmonary injury and proliferated fibroblasts. A higher interaction of β-catenin with TCF and a lower interaction of β-catenin with Foxo1 was found in BLM group compared to the control group. TGF-β1 promoted β-catenin/TCF, whereas ICG-001 inhibited β-catenin/TCF, and promoted β-catenin/Foxo1. Furthermore, ICG-001 reversed TGF-β1 induced largely production of inflammatory cytokines and accumulation of extracellular matrix, as well as high expression of α-SMA. However, AS1842856, a FOXO1 antagonist, strengthened the effects induced by TGF-β1. In summary, our study revealed that β-catenin/Foxo1 protected against IPF through inhibiting inflammatory response and extracellular matrix accumulation, providing an alternative approach to explain the potential mechanism of IPF and seek for more effective therapeutic drugs.

scholarly journals Nanostructures Control the Hepatocellular Responses to a Cytotoxic Agent “Cisplatin”

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Shimaa A. Abdellatef ◽  
Riho Tange ◽  
Takeshi Sato ◽  
Akihiko Ohi ◽  
Toshihide Nabatame ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Chemotherapeutic Agent ◽  
Chromatin Condensation ◽  
Cellular Responses ◽  
Flat Surfaces ◽  
Flat Substrate ◽  
Cells Cultured

In drug discovery programs, the alteration betweenin vivoandin vitrocellular responses to drug represents one of the main challenges. Since the variation in the native extracellular matrix (ECM) betweenin vivoand 2Din vitroconditions is one of the key reasons for such discrepancies, thus the utilization of substrate that likely mimics ECM characteristics (topography, stiffness, and chemical composition) is needed to overcome such problem. Here, we investigated the role of substrate nanotopography as one of the major determinants of hepatic cellular responses to a chemotherapeutic agent “cisplatin.” We studied the substratum induced variations in cisplatin cytotoxicity; a higher cytotoxic response to cisplatin was observed for cells cultured on the nanopattern relative to a flat substrate. Moreover, the nanofeatures with grating shapes that mimic the topography of major ECM protein constituents (collagen) induced alterations in the cellular orientation and chromatin condensation compared to flat surfaces. Accordingly, the developments of biomimetic substrates with a particular topography could have potentials in drug development analyses to reflect more physiological mimicry conditionsin vitro.

scholarly journals Role of DnaK in In Vitro and In Vivo Expression of Virulence Factors of Vibrio cholerae

1999 ◽  
Vol 67 (3) ◽  
pp. 1025-1033 ◽  
Author(s):  
Sabyasachi Chakrabarti ◽  
Nilanjan Sengupta ◽  
Rukhsana Chowdhury
Keyword(s):  
Heat Shock ◽  
Vibrio Cholerae ◽  
Virulence Factors ◽  
Heat Shock Gene ◽  
Insertion Mutant ◽  
In Vivo Expression ◽  
Shock Gene

ABSTRACT The dnaK gene of Vibrio cholerae was cloned, sequenced, and used to construct a dnaK insertion mutant which was then used to examine the role of DnaK in expression of the major virulence factors of this important human pathogen. The central regulator of several virulence genes of V. choleraeis ToxR, a transmembrane DNA binding protein. The V. cholerae dnaK mutant grown in standard laboratory medium exhibited phenotypes characteristic of cells deficient in ToxR activity. Using Northern blot analysis and toxR transcriptional fusions, we demonstrated a reduction in expression of the toxR gene in the dnaK mutant strain together with a concomitant increase in expression of a htpG-like heat shock gene that is located immediately upstream and is divergently transcribed fromtoxR. This may be due to increased heat shock induction in the dnaK mutant. In vivo, however, although expression from heat shock promoters in the dnaK mutant was similar to that observed in vitro, expression of both toxR andhtpG was comparable to that by the parental strain. In both strains, in vivo expression of toxR was significantly higher than that observed in vitro, but no reciprocal decrease inhtpG expression was observed. These results suggest that the modulation of toxR expression in vivo may be different from that observed in vitro.

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