Myofibrillar degeneration with diphtheria toxin

2020 ◽  
Vol 45 (4) ◽  
pp. 351-357
Author(s):  
Bilge Özerman Edis ◽  
Muhammet Bektaş ◽  
Rüstem Nurten
Keyword(s):  
Protein Synthesis ◽  
Actin Filaments ◽  
Diphtheria Toxin ◽  
Cardiac Tissue ◽  
Culture Conditions ◽  
Bacterial Toxin ◽  
Filamentous Actin ◽  
Cardiac Damage ◽  
Tissue Samples

AbstractObjectivesCardiac damage in patient with diphtheritic myocarditis is reported as the leading cause of mortality. Diphtheria toxin (DTx) is a well-known bacterial toxin inducing various cytotoxic effects. Mainly, catalytic fragment inhibits protein synthesis, induces cytotoxicity, and depolymerizes actin filaments. In this study, we aimed to demonstrate the extent of myofibrillar damage under DTx treatment to porcine cardiac tissue samples.MethodsTissue samples were incubated with DTx for 1–3 h in culture conditions. To analyze whole toxin (both fragments) distribution, conjugation of DTx with FITC was performed. Measurements were carried out with fluorescence spectrophotometer before and after dialysis. Immunofluorescence microscopy was used to show localization of DTx-FITC (15 nM) on cardiac tissue incubated for 2 h. Ultrastructural characterization of cardiac tissue samples treated with DTx (15 or 150 nM) was performed with transmission electron microscopy.ResultsDTx exerts myofibrillar disorganization. Myofilament degeneration, mitochondrial damage, vacuolization, and abundant lipid droplets were determined with 150 nM of DTx treatment.ConclusionsThis finding is an addition to depolymerization of actin filaments as a result of the DTx-actin interactions in in vitro conditions, indicating that myofilament damage can occur with DTx directly besides protein synthesis inhibition. Ultrastructural results support the importance of filamentous actin degeneration at diphtheritic myocarditis.

Biophysical stimulation for in vitro engineering of functional cardiac tissues

2017 ◽  
Vol 131 (13) ◽  
pp. 1393-1404 ◽  
Author(s):  
Anastasia Korolj ◽  
Erika Yan Wang ◽  
Robert A. Civitarese ◽  
Milica Radisic
Keyword(s):  
Cardiac Tissue ◽  
Culture Media ◽  
Culture Conditions ◽  
Lineage Specification ◽  
Cardiac Tissues ◽  
Cardiac Lineage ◽  
And Function ◽  
Tissue Models

Engineering functional cardiac tissues remains an ongoing significant challenge due to the complexity of the native environment. However, our growing understanding of key parameters of the in vivo cardiac microenvironment and our ability to replicate those parameters in vitro are resulting in the development of increasingly sophisticated models of engineered cardiac tissues (ECT). This review examines some of the most relevant parameters that may be applied in culture leading to higher fidelity cardiac tissue models. These include the biochemical composition of culture media and cardiac lineage specification, co-culture conditions, electrical and mechanical stimulation, and the application of hydrogels, various biomaterials, and scaffolds. The review will also summarize some of the recent functional human tissue models that have been developed for in vivo and in vitro applications. Ultimately, the creation of sophisticated ECT that replicate native structure and function will be instrumental in advancing cell-based therapeutics and in providing advanced models for drug discovery and testing.

The effect of osmolarity on mouse parthenogenesis

Development ◽  
1974 ◽  
Vol 31 (2) ◽  
pp. 513-526
Author(s):  
M. H. Kaufman ◽  
M. A. H. Surani
Keyword(s):  
Protein Synthesis ◽  
Culture Medium ◽  
Culture Media ◽  
Polar Body ◽  
Amino Acid Mixture ◽  
Culture Conditions ◽  
Follicle Cells ◽  
Acid Mixture ◽  
Second Polar Body

Eggs from (C57B1 × A2G)F1 mice were activated by treatment with hyaluronidase, which removed the follicle cells, and cultured in vitro. Observations were made 6–8 h after hyaluronidase treatment to determine the frequency of activation and the types of parthenogenones induced. Cumulus-free eggs resulting from hyaluronidase treatment were incubated for 2¼ h in culture media of various osmolarities. The frequency of activation was found to be dependent on the postovulatory age of oocytes, while the types of parthenogenones induced were dependent on the osmolarity of the in vitro culture medium and their postovulatory age. Culture in low osmolar medium suppressed the extrusion of the second polar body (2PB). This decreased the incidence of haploid eggs with a single pronucleus and 2PB and immediately cleaved eggs from 97·5% to 42·3% of the activated population. Where 2PB extrusion had been suppressed, 97·4% of parthenogenones contained two haploid pronuclei. Very few were observed with a single and presumably diploid pronucleus. Serial observations from 11 to 18 h after hyaluronidase treatment were made on populations of activated eggs as they entered the first cleavage mitosis after 2¼ h incubation in medium either of normal (0·287 osmol) or low (0·168 osmol) osmolarity. A delay in the time of entry into the first cleavage mitosis similar to the duration of incubation in low osmolar medium was observed. Further, eggs were incubated in control and low osmolar culture media containing uniformly labelled [U-14C]amino acid mixture to examine the extent of protein synthesis in recently activated eggs subjected to these culture conditions. An hypothesis is presented to explain the effect of incubation in low osmolar culture medium in delaying the first cleavage mitosis.

scholarly journals β-catenin/LEF1/IGF-IIR Signaling Axis Galvanizes the Angiotensin-II- induced Cardiac Hypertrophy

2019 ◽  
Vol 20 (17) ◽  
pp. 4288 ◽  
Author(s):  
Chin-Hu Lai ◽  
Sudhir Pandey ◽  
Cecilia Hsuan Day ◽  
Tsung-Jung Ho ◽  
Ray-Jade Chen ◽  
...  
Keyword(s):  
Cardiac Hypertrophy ◽  
Cardiac Tissue ◽  
Ang Ii ◽  
Consensus Binding Site ◽  
Tissue Samples ◽  
Spontaneously Hypertensive ◽  
Signaling Axis ◽  
Causes Of Mortality

Cardiovascular diseases have a high prevalence worldwide and constitute the leading causes of mortality. Recently, malfunctioning of β-catenin signaling has been addressed in hypertensive heart condition. Ang-II is an important mediator of cardiovascular remodeling processes which not only regulates blood pressure but also leads to pathological cardiac changes. However, the contribution of Ang-II/β-catenin axis in hypertrophied hearts is ill-defined. Employing in vitro H9c2 cells and in vivo spontaneously hypertensive rats (SHR) cardiac tissue samples, western blot analysis, luciferase assays, nuclear-cytosolic protein extracts, and immunoprecipitation assays, we found that under hypertensive condition β-catenin gets abnormally induced that co-activated LEF1 and lead to cardiac hypertrophy changes by up-regulating the IGF-IIR signaling pathway. We identified putative LEF1 consensus binding site on IGF-IIR promoter that could be regulated by β-catenin/LEF1 which in turn modulate the expression of cardiac hypertrophy agents. This study suggested that suppression of β-catenin expression under hypertensive condition could be exploited as a clinical strategy for cardiac pathological remodeling processes.

scholarly journals Infiltrated Macrophages Die of Pneumolysin-Mediated Necroptosis following Pneumococcal Myocardial Invasion

2016 ◽  
Vol 84 (5) ◽  
pp. 1457-1469 ◽  
Author(s):  
Ryan P. Gilley ◽  
Norberto González-Juarbe ◽  
Anukul T. Shenoy ◽  
Luis F. Reyes ◽  
Peter H. Dube ◽  
...  
Keyword(s):  
Cardiac Tissue ◽  
Immune Cell ◽  
Kinase Domain ◽  
Cardiac Damage ◽  
Interacting Protein ◽  
Hydropic Degeneration ◽  
Content Type ◽  
Tissue Sections ◽  
Hematoxylin And Eosin

Streptococcus pneumoniae(the pneumococcus) is capable of invading the heart. Herein we observed that pneumococcal invasion of the myocardium occurred soon after development of bacteremia and was continuous thereafter. Using immunofluorescence microscopy (IFM), we observed thatS. pneumoniaereplication within the heart preceded visual signs of tissue damage in cardiac tissue sections stained with hematoxylin and eosin. DifferentS. pneumoniaestrains caused distinct cardiac pathologies: strain TIGR4, a serotype 4 isolate, caused discrete pneumococcus-filled microscopic lesions (microlesions), whereas strain D39, a serotype 2 isolate, was, in most instances, detectable only using IFM and was associated with foci of cardiomyocyte hydropic degeneration and immune cell infiltration. Both strains efficiently invaded the myocardium, but cardiac damage was entirely dependent on the pore-forming toxin pneumolysin only for D39. Early microlesions caused by TIGR4 and microlesions formed by a TIGR4 pneumolysin-deficient mutant were infiltrated with CD11b+and Ly6G-positive neutrophils and CD11b+and F4/80-positive (F4/80+) macrophages. We subsequently demonstrated that macrophages in TIGR4-infected hearts died as a result of pneumolysin-induced necroptosis. The effector of necroptosis, phosphorylated mixed-lineage kinase domain-like protein (MLKL), was detected in CD11b+and F4/80+cells associated with microlesions. Likewise, treatment of infected mice and THP-1 macrophagesin vitrowith the receptor-interacting protein 1 kinase (RIP1) inhibitor necrostatin-5 promoted the formation of purulent microlesions and blocked cell death, respectively. We conclude that pneumococci that have invaded the myocardium are an important cause of cardiac damage, pneumolysin contributes to cardiac damage in a bacterial strain-specific manner, and pneumolysin kills infiltrated macrophages via necroptosis, which alters the immune response.

scholarly journals Overexpression of cofilin stimulates bundling of actin filaments, membrane ruffling, and cell movement in Dictyostelium.

1996 ◽  
Vol 132 (3) ◽  
pp. 335-344 ◽  
Author(s):  
H Aizawa ◽  
K Sutoh ◽  
I Yahara
Keyword(s):  
Actin Filaments ◽  
Cell Movement ◽  
Structure And Function ◽  
Cross Linking ◽  
Low Molecular Weight ◽  
Filamentous Actin ◽  
Membrane Ruffling ◽  
And Function

Cofilin is a low molecular weight actin-modulating protein whose structure and function are conserved among eucaryotes. Cofilin exhibits in vitro both a monomeric actin-sequestering activity and a filamentous actin-severing activity. To investigate in vivo functions of cofilin, cofilin was overexpressed in Dictyostelium discoideum cells. An increase in the content of D. discoideum cofilin (d-cofilin) by sevenfold induced a co-overproduction of actin by threefold. In cells over-expressing d-cofilin, the amount of filamentous actin but not that of monomeric actin was increased. Overexpressed d-cofilin co-sedimented with actin filaments, suggesting that the sequestering activity of d-cofilin is weak in vivo. The overexpression of d-cofilin increased actin bundles just beneath ruffling membranes where d-cofilin was co-localized. The overexpression of d-cofilin also stimulated cell movement as well as membrane ruffling. We have demonstrated in vitro that d-cofilin transformed latticework of actin filaments cross-linked by alpha-actinin into bundles probably by severing the filaments. D. discoideum cofilin may sever actin filaments in vivo and induce bundling of the filaments in the presence of cross-linking proteins so as to generate contractile systems involved in membrane ruffling and cell movement.

Melatonin decreases circulating Trypanosoma cruzi load with no effect on tissue parasite replication.

2020 ◽  
Author(s):  
MAIARA VOLTARELLI PROVIDELLO ◽  
Gisele Bulhões Portapilla ◽  
Pedro Alexandre Sampaio Oliveira ◽  
Carla Brigagão Pacheco da Silva ◽  
Naira Ferreira Anchieta ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Cardiac Tissue ◽  
Direct Action ◽  
Protective Action ◽  
Cardiac Damage ◽  
Redox Imbalance ◽  
Parasitic Load ◽  
Parasite Replication

Cardiac damage during the acute phase of Chagas disease (CD) is associated with an increase in pro-inflammatory markers and oxidative stress. Melatonin has emerged as a promising therapy for CD due to its antioxidant and immunomodulatory properties. However, the protective action of melatonin in the cardiac tissue as well as its direct action on the parasite cycle is not fully understood. We investigated the effects of melatonin on heart parasitism in mice infected with Trypanosoma cruzi (T. cruzi) and also its effects on the parasitic proliferation in vitro. Our in vivo study showed that melatonin reduced circulating parasitemia load, but did not control tissue (heart, liver and spleen) parasitism in mice. Melatonin did not prevent the redox imbalance in the left ventricle of infected mice. Our in vitro findings showed that melatonin did not inhibit parasites replication within cells, but rather increased their release from cells. Melatonin did not control parasitism load in the heart or prevented the cardiac redox imbalance induced by acute T. cruzi infection. The hormone controlled the circulating parasitic load, but in cells melatonin accelerated parasitic release, a response that can be harmful.

Abstract 213: Evolving Challenges in Promoting Stem Cell Based Cardiovascular Repair and Regeneration

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Mani T Valarmathi ◽  
Jiang Li
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cardiac Muscle ◽  
Adult Stem Cells ◽  
Cardiac Tissue ◽  
Three Dimensional ◽  
Induced Pluripotent Stem Cell ◽  
Myocardial Damage ◽  
Culture Conditions

Introduction: Use of adult stem cells in the stimulation of mammalian cardiac muscle regeneration is in its infancy, and to date, it has been difficult to determine the efficacy of the procedures that have been employed. The outstanding question remains whether stem cells derived from the bone-marrow or some other location within or outside of the heart can populate a region of myocardial damage and transform into tissue-specific cells, and also exhibit functional synchronization. As a result, this necessitates the development of an appropriate in vitro three-dimensional (3-D) model of cardiomyogenesis and prompts the development of a 3-D cardiac muscle construct for tissue engineering purposes, especially using the adult stem cells. Hypothesis: Functioning vascularized cardiac tissue can be generated by the interaction of human induced pluripotent stem cell-derived embryonic cardiac myocytes (hiPSC-ECMs) and human multipotent mesenchymal stem cells (hMSCs) on a 3-D prevascularized collagen cell carrier (CCC) scaffold. Methods and Results: In order to achieve the above aim, we have developed an in vitro 3-D functioning vascularized cardiac muscle construct using hiPSC-ECMs and hMSCs. First, to generate the prevascularized scaffold, human cardiac microvascular endothelial cells (hCMVECs) and hMSCs were co-cultured on 3-D CCCs for 7 days under vasculogenic culture conditions, hCMVECs/hMSCs underwent maturation, differentiation, and morphogenesis characteristic of micro vessels, and formed extensive plexuses of vascular networks. Next, the hiPSC-ECMs and hMSCs were co-cultured onto this generated prevascularized CCCs for further 7 or 14 days in myogenic culture conditions. Finally, the vascular and cardiac phenotypic inductions were analyzed at the morphological, immunological, biochemical, molecular, and functional levels. Expression and functional analyses of the differentiated cells revealed dramatic neo-angiogenesis and neo-cardiomyogenesis. Conclusions: Thus, our unique 3-D co-culture system provided us the apt in vitro functioning prevascularized 3-D cardiac patch that can be utilized for cellular cardiomyoplasty.

scholarly journals A Toxin Involved inSalmonellaPersistence Regulates Its Activity by Acetylating Its Cognate Antitoxin, a Modification Reversed by CobB Sirtuin Deacetylase

mBio ◽  
2017 ◽  
Vol 8 (3) ◽  
Author(s):  
Chelsey M. VanDrisse ◽  
Anastacia R. Parks ◽  
Jorge C. Escalante-Semerena
Keyword(s):  
Protein Synthesis ◽  
Pathogenic Bacteria ◽  
Bacterial Toxin ◽  
Host Defenses ◽  
Mobility Shift ◽  
Reverse Transcription Pcr ◽  
Acetylation State ◽  
Host Infection

ABSTRACTBacterial toxin-antitoxin systems trigger the onset of a persister state by inhibiting essential cellular processes. The TacT toxin ofSalmonella entericais known to induce a persister state in macrophages through the acetylation of aminoacyl-tRNAs. Here, we show that the TacT toxin and the TacA antitoxin work as a complex that modulates TacT activity via the acetylation state of TacA. TacT acetylates TacA at residue K44, a modification that is removed by the NAD+-dependent CobB sirtuin deacetylase. TacA acetylation increases the activity of TacT, downregulating protein synthesis. TacA acetylation altered binding to its own promoter, although this did not changetacATexpression levels. These claims are supported by results fromin vitroprotein synthesis experiments used to monitor TacT activity,in vivogrowth analyses, electrophoretic mobility shift assays, and quantitative reverse transcription-PCR (RT-qPCR) analysis. TacT is the first example of a Gcn5-relatedN-acetyltransferase that modifies nonprotein and protein substrates.IMPORTANCEDuring host infection, pathogenic bacteria can modulate their physiology to evade host defenses. Some pathogens use toxin-antitoxin systems to modulate a state of self-toxicity that can decrease their cellular activity, triggering the onset of a persister state. The lower metabolic activity of persister cells allows them to escape host defenses and antibiotic treatments. Hence a better understanding of the mechanisms used by pathogens to ingress and egress the persister state is of relevance to human health.

scholarly journals THE NEUTRALIZATION OR DESTRUCTION OF DIPHTHERIA TOXIN BY TISSUE

1931 ◽  
Vol 53 (6) ◽  
pp. 821-826 ◽  
Author(s):  
Augustus Wadsworth ◽  
Ella N. Hoppe
Keyword(s):  
Guinea Pig ◽  
Cardiac Muscle ◽  
Muscle Tissue ◽  
Guinea Pigs ◽  
Diphtheria Toxin ◽  
Cardiac Tissue ◽  
Tissue Cultures ◽  
Adult Heart ◽  
Embryo Extract

As determined by the intracutaneous test in guinea pigs, diphtheria toxin is not altered in the presence of cardiac tissue obtained from the fetal or from the adult heart of the guinea pig. Tissue cultures were apparently uninjured by the presence of the toxin in the dilutions used in these experiments, and, when washed with embryo extract after removal of the diluted toxin, continued to grow. Embryonic guinea pig cardiac muscle tissue growing in cultures in vitro possesses the power of neutralizing, binding, or destroying diphtheria toxin so that it is no longer toxic for normal guinea pigs. Such neutralization takes place through the intervention of growing tissue and is a property which is lacking in similar surviving tissue not in a state of cultivation. Thus, it appears that the living, growing cells of the tissues neutralize or destroy limited quantities of toxin; only when the quantity of toxin exceeds a certain limit is its action injurious.

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