Dataset Information

Genetic ablation of fibroblast activation protein alpha attenuates left ventricular dilation after myocardial infarction.

ABSTRACT:

Introduction

Regulating excessive activation of fibroblasts may be a promising target to optimize extracellular matrix deposition and myocardial stiffness. Fibroblast activation protein alpha (FAP) is upregulated in activated fibroblasts after myocardial infarction (MI), and alters fibroblast migration in vitro. We hypothesized that FAP depletion may have a protective effect on left ventricular (LV) remodeling after MI.

Materials and methods

We used the model of chronic MI in homozygous FAP deficient mice (FAP-KO, n = 51) and wild type mice (WT, n = 55) to analyze wound healing by monocyte and myofibroblast infiltration. Heart function and remodeling was studied by echocardiography, morphometric analyses including capillary density and myocyte size, collagen content and in vivo cell-proliferation. In non-operated healthy mice up to 6 months of age, morphometric analyses and collagen content was assessed (WT n = 10, FAP-KO n = 19).

Results

Healthy FAP-deficient mice did not show changes in LV structure or differences in collagen content or cardiac morphology. Infarct size, survival and cardiac function were not different between FAP-KO and wildtype mice. FAP-KO animals showed less LV-dilation and a thicker scar, accompanied by a trend towards lower collagen content. Wound healing, assessed by infiltration with inflammatory cells and myofibroblasts were not different between groups.

Conclusion

We show that genetic ablation of FAP does not impair cardiac wound healing, and attenuates LV dilation after MI in mice. FAP seems dispensable for normal cardiac function and homeostasis.

SUBMITTER: Hoffmann DB

PROVIDER: S-EPMC7935287 | biostudies-literature | 2021

REPOSITORIES: biostudies-literature

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Publications

Genetic ablation of fibroblast activation protein alpha attenuates left ventricular dilation after myocardial infarction.

Hoffmann Daniel B DB Fraccarollo Daniela D Galuppo Paolo P Frantz Stefan S Bauersachs Johann J Tillmanns Jochen J

PloS one 20210305 3

<h4>Introduction</h4>Regulating excessive activation of fibroblasts may be a promising target to optimize extracellular matrix deposition and myocardial stiffness. Fibroblast activation protein alpha (FAP) is upregulated in activated fibroblasts after myocardial infarction (MI), and alters fibroblast migration in vitro. We hypothesized that FAP depletion may have a protective effect on left ventricular (LV) remodeling after MI.<h4>Materials and methods</h4>We used the model of chronic MI in homo ...[more]

PMID: 33667270

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Project description:We report a genome-wide survey of early responses of the mouse heart transcriptome to acute myocardial infarction (AMI). For three regions of the left ventricle (LV), namely ischemic/infarcted tissue (IF), the surviving LV free wall (FW) and the interventricular septum (IVS), 36,899 transcripts were assayed at six time points from 15 min to 48 h post-AMI in both AMI and sham surgery mice. For each transcript, temporal expression patterns were systematically compared between AMI and sham groups, which identified 515 AMI-responsive genes in IF tissue, 35 in the FW, 7 in the IVS, with three genes induced in all three regions. Using the literature, we assigned functional annotations to all 519 nonredundant AMI-induced genes and present two testable models for central signaling pathways induced early post-AMI. First, the early induction of 15 genes involved in assembly and activation of the activator protein-1 (AP-1) family of transcription factors implicates AP-1 as a dominant regulator of earliest post-ischemic molecular events. Second, dramatic increases in transcripts for arginase 1 (ARG1), the enzymes of polyamine biosynthesis and protein inhibitor of nitric oxide synthase (NOS) activity indicates that NO production may be regulated, in part, by inhibition of NOS and coordinate depletion of the NOS substrate, L-arginine. ARG1 was the single most highly induced transcript in the database (121-fold in IF region) and its induction in heart has not been previously reported. Keywords: heart attack, mouse, time course, regional responses We report temporal and regional changes in steady state mRNA levels in the mouse LV following a surgically-induced AMI. Three regions of the infarcted LV were surveyed: IF, FW and IVS. For each region, mRNA levels were assayed at t=0 and six time points after occlusion of the left anterior descending coronary artery (t = 15 min, 1 h, 4 h, 12 h, 24 h, 48 h). As control, an identical time course was carried out in the mouse LV after sham surgery in which the suture was passed under the artery, but not ligated. For sham surgical mice and naïve mice (t=0), the IVS and the LV free wall were harvested and assayed. The AMI and sham time courses were repeated for a total of two independent repetitions of the experiment. For each repetition, 96 GeneChips were hybridized. Thus, for two repetitions, 192 GeneChips (2 x 96) were hybridized. In addition, the naïve time point was assayed a second time during Repetition 1 for six additional GeneChips (two tissues x three chips). The overall total number of samples is 198 GeneChips (192 + 6). Total RNA was isolated from each individual tissue sample. Equal weights of total RNA from 4-10 mice were combined for each LV region, time point and treatment. Copy RNA mixtures were synthesized from each total RNA pool and hybridized to the Affymetrix GeneChip set MG U74 v2 (A, B, and C) that carries 36,899 probe sets. The global normalization of fluorescence emissions for the 198 GeneChips used in this study and their conversion to relative transcript concentrations measured in relative fluorescence units (RFU) was conducted using Robust Multi-array Averaging (RMA; www.bioconductor.org). Each of the 198 Accessions is titled as follows: time point / treatment / tissue, repetition, GeneChip. The additional assays of naïve mice in Repetition 1 are labeled “Naive2”.

Dataset Information

Genetic ablation of fibroblast activation protein alpha attenuates left ventricular dilation after myocardial infarction.

Introduction

Materials and methods

Results

Conclusion

Publications

Genetic ablation of fibroblast activation protein alpha attenuates left ventricular dilation after myocardial infarction.

Similar Datasets

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