A refined TTC assay precisely detects cardiac injury and cellular viability in the infarcted mouse heart.

Histological analysis with 2,3,5-triphenyltetrazolium chloride (TTC) staining is the most frequently used tool to detect myocardial ischemia/reperfusion injury. However, its practicality is often challenged by poor image quality in gross histology, leading to an equivocal infarct-boundary delineation and potentially compromised measurement accuracy. Here, we introduce several crucial refinements in staining protocol and sample processing, which enable TTC images to be analyzed with light microscopy.

Constitutive Activation of gp130 in T Cells Results in Senescence and Premature Aging.

IL-6 family members contribute to host defense through the stimulation of acute-phase signaling, hematopoiesis, immune reactions, and regenerative processes. To investigate essential mechanisms that are linked toward a constitutively activated gp130 signaling, we generated and characterized a mouse model that reflects a constitutive and cytokine-independent activation of JAK/STAT3 signaling by Lgp130 in CD4- and CD8-positive T cells. Lgp130 is an engineered form of gp130 in which dimerization and activation are forced by a leucine zipper.

IL-6 in the infarcted heart is preferentially formed by fibroblasts and modulated by purinergic signaling.

Plasma IL-6 is elevated after myocardial infarction (MI) and is associated with increased morbidity and mortality. Which cardiac cell type preferentially contributes to IL-6 expression and how its production is regulated are largely unknown. Here, we studied the cellular source and purinergic regulation of IL-6 formation in a murine MI model.

Cardiac injection of USSC boosts remuscularization of the infarcted heart by shaping the T-cell response.

Regenerating the injured heart remains one of the most vexing challenges in cardiovascular medicine. Cell therapy has shown potential for treatment of myocardial infarction, but low cell retention so far has limited its success. Here we show that intramyocardial injection of highly apoptosis-resistant unrestricted somatic stem cells (USSC) into infarcted rat hearts resulted in an unprecedented thickening of the left ventricular wall with cTnT/BrdU cardiomyocytes that was paralleled by progressively restored ejection fraction.

The Mycotoxin Beauvericin Exhibits Immunostimulatory Effects on Dendritic Cells Activating the TLR4 Signaling Pathway.

Beauvericin (BEA), a mycotoxin of the enniatin family produced by various toxigenic fungi, has been attributed multiple biological activities such as anti-cancer, anti-inflammatory, and anti-microbial functions. However, effects of BEA on dendritic cells remain unknown so far. Here, we identified effects of BEA on murine granulocyte-macrophage colony-stimulating factor (GM-CSF)-cultured bone marrow derived dendritic cells (BMDCs) and the underlying molecular mechanisms.

Acute Heart Failure After Reperfused Ischemic Stroke: Association With Systemic and Cardiac Inflammatory Responses.

Patients with acute ischemic stroke (AIS) present an increased incidence of systemic inflammatory response syndrome and release of Troponin T coinciding with cardiac dysfunction. The nature of the cardiocirculatory alterations remains obscure as models to investigate systemic interferences of the brain-heart-axis following AIS are sparse. Thus, this study aims to investigate acute cardiocirculatory dysfunction and myocardial injury in mice after reperfused AIS.

Single-cell transcriptomics defines heterogeneity of epicardial cells and fibroblasts within the infarcted murine heart.

In the adult heart, the epicardium becomes activated after injury, contributing to cardiac healing by secretion of paracrine factors. Here, we analyzed by single-cell RNA sequencing combined with RNA in situ hybridization and lineage tracing of Wilms tumor protein 1-positive (WT1) cells, the cellular composition, location, and hierarchy of epicardial stromal cells (EpiSC) in comparison to activated myocardial fibroblasts/stromal cells in infarcted mouse hearts. We identified 11 transcriptionally distinct EpiSC populations, which can be classified into three groups, each containing a cluster of proliferating cells.

Normoxic induction of HIF-1α by adenosine-A R signaling in epicardial stromal cells formed after myocardial infarction.

Myocardial infarction (MI) activates the epicardium to form epicardial stromal cells (EpiSC) that reside in the epicardial hypoxic microenvironment. Paracrine factors secreted by EpiSC were shown to modulate the injury response of the post-MI heart and improve cardiac function. We have previously reported that the expression of the angiogenic cytokines vascular endothelial growth factor A (VEGFA) and IL-6 is strongly upregulated in EpiSC by adenosine acting via the A receptor (A R).

Endogenous CD83 Expression in CD4 Conventional T Cells Controls Inflammatory Immune Responses.

The glycoprotein CD83 is known to be expressed by different immune cells including activated CD4Foxp3 regulatory T cells (Tregs) and CD4Foxp3 conventional T cells. However, the physiological function of endogenous CD83 in CD4 T cell subsets is still unclear. In this study, we have generated a new CD83 mouse line on BALB/c background, allowing for specific ablation of CD83 in T cells upon breeding with CD4-cre mice.

Nucleotide ecto-enzyme metabolic pattern and spatial distribution in calcific aortic valve disease; its relation to pathological changes and clinical presentation.

Background: Extracellular nucleotide metabolism contributes to chronic inflammation, cell differentiation, and tissue mineralization by controlling nucleotide and adenosine concentrations and hence its purinergic effects. This study investigated location-specific changes of extracellular nucleotide metabolism in aortic valves of patients with calcific aortic valve disease (CAVD). Individual ecto-enzymes and adenosine receptors involved were analyzed together with correlation with CAVD severity and risk factors.

AR-dependent signaling alters immune cell composition and enhances IL-6 formation in the ischemic heart.

Although the cardioprotective effect of adenosine is undisputed, the role of the adenosine A receptor (AR) in ischemic cardiac remodeling is not defined. In this study we aimed to unravel the role AR plays in modulating the immune response and the healing mechanisms after myocardial infarction. Genetic and pharmacological (PSB603) inactivation of AR as well as activation of AR with BAY60-6583 does not alter cardiac remodeling of the infarcted (50-min left anterior descending artery occlusion/reperfusion) murine heart.

IL-23R Signaling Plays No Role in Myocardial Infarction.

Ischemic heart diseases are the most frequent diseases in the western world. Apart from Interleukin (IL-)1, inflammatory therapeutic targets in the clinic are still missing. Interestingly, opposing roles of the pro-inflammatory cytokine IL-23 have been described in cardiac ischemia in mice.

MicroRNA-183 and microRNA-96 are associated with autoimmune responses by regulating T cell activation.

MircoRNAs (miRs) are small molecules that regulate gene expression at the posttranscriptional level. They have been proposed to be involved in the regulation of several immune responses including autoimmunity. Here, we identified miR-183 and miR-96 to be highly expressed in CD4 T cells from peripheral blood of Graves' orbitopathy (GO) patients as well as in human and murine T cells upon activation in vitro.

CD73 on T Cells Orchestrates Cardiac Wound Healing After Myocardial Infarction by Purinergic Metabolic Reprogramming.

Background: T cells are required for proper healing after myocardial infarction. The mechanism of their beneficial action, however, is unknown. The proinflammatory danger signal ATP, released from damaged cells, is degraded by the ectonucleotidases CD39 and CD73 to the anti-inflammatory mediator adenosine.

Adenosine Formed by CD73 on T Cells Inhibits Cardiac Inflammation and Fibrosis and Preserves Contractile Function in Transverse Aortic Constriction-Induced Heart Failure.

Background: Structural damage during heart failure development leads to increased infiltration of leukocytes. Because purinergic signaling on immune cells may impact on the inflammatory response, we evaluated the role of ecto-5'-nucleotidase (CD73) on the development of heart failure after transverse aortic constriction (TAC) using global and T-cell-specific CD73 mice.

Methods And Results: Leukocytes infiltrating the failing heart were analyzed by a multistep enzymatic procedure over a period of 16 weeks using fluorescence-activated cell sorting.

Clinical-grade regulatory T cells: Comparative analysis of large-scale expansion conditions.

Recent clinical trials have indicated the high potential of regulatory T cells (Tregs) in the prevention of acute and chronic graft-versus-host disease (GvHD) after hematopoietic stem cell transplantation, but immune interventions require large numbers of Tregs. With respect to their limited natural occurrence, development and optimization of protocols for large-scale expansion of clinical-grade Tregs are essential if considered for therapeutic use. We compared different clinical-grade large-scale expansion protocols for repetitive transfer of large numbers of Tregs in clinical trials for the prevention of acute and/or chronic GvHD.

Granzyme A Is Required for Regulatory T-Cell Mediated Prevention of Gastrointestinal Graft-versus-Host Disease.

In our previous work we could identify defects in human regulatory T cells (Tregs) likely favoring the development of graft-versus-host disease (GvHD) following allogeneic stem cell transplantation (SCT). Treg transcriptome analyses comparing GvHD and immune tolerant patients uncovered regulated gene transcripts highly relevant for Treg cell function. Moreover, granzyme A (GZMA) also showed a significant lower expression at the protein level in Tregs of GvHD patients.

Neuropilin 1 deficiency on CD4+Foxp3+ regulatory T cells impairs mouse melanoma growth.

Infiltration of Foxp3(+) regulatory T (T reg) cells is considered to be a critical step during tumor development and progression. T reg cells supposedly suppress locally an effective anti-tumor immune response within tumor tissues, although the precise mechanism by which T reg cells infiltrate the tumor is still unclear. We provide evidence that Neuropilin 1 (Nrp-1), highly expressed by Foxp3(+) T reg cells, regulates the immunological anti-tumor control by guiding T reg cells into the tumor in response to tumor-derived vascular endothelial growth factor (VEGF).

Anti-retroviral effects of type I IFN subtypes in vivo.

Type I IFN play a very important role in immunity against viral infections. Murine type I IFN belongs to a multigene family including 14 IFN-alpha subtypes but the biological functions of IFN-alpha subtypes in retroviral infections are unknown. We have used the Friend retrovirus model to determine the anti-viral effects of IFN-alpha subtypes in vitro and in vivo.