Abstract
Cardiac levels of the signal transducer and activator of transcription factor-3 (STAT3) decline with age, and male but not female mice with a cardiomyocyte-specific STAT3 deficiency (CKO) display premature age-related heart failure associated with reduced cardiac capillary density. In the present study isolated male and female CKO-cardiomyocytes exhibit increased prostaglandin (PG)-generating cyclooxygenase-2 (COX-2) expression. The PG-degrading hydroxyprostaglandin-dehydrogenase-15 (HPGD) expression is only reduced in male cardiomyocytes, which is associated with increased PGD2 secretion from isolated male but not female CKO-cardiomyocytes. Reduced HPGD expression in male cardiomyocytes derive from impaired androgen-receptor-(AR)-signaling due to loss of its co-factor STAT3. Elevated PGD2 secretion in males is associated with increased white adipocyte accumulation in aged male but not female hearts. Adipocyte differentiation is enhanced in isolated SCA-1+-cardiac-progenitor-cells (CPC) from young male CKO-mice compared to the adipocyte differentiation of male wildtype (WT)-CPC and CPC isolated from female mice. Epigenetic analysis in freshly isolated male CKO-CPC display hypermethylation in pro-angiogenic genes (Fgfr2, Epas1) and hypomethylation in the white adipocyte differentiation gene Zfp423 associated with upregulated ZFP423 expression and a shift from endothelial to white adipocyte differentiation compared to WT-CPC. The expression of the histone-methyltransferase EZH2 is reduced in male CKO-CPC compared to male WT-CPC whereas no differences in the EZH2 expression in female CPC were observed. Clonally expanded CPC can differentiate into endothelial cells or into adipocytes depending on the differentiation conditions. ZFP423 overexpression is sufficient to induce white adipocyte differentiation of clonal CPC. In isolated WT-CPC, PGD2 stimulation reduces the expression of EZH2 thereby upregulating ZFP423 expression and promoting white adipocyte differentiation.
Thus, cardiomyocyte STAT3-deficiency leads to age-related and sex-specific cardiac remodeling and failure in part due to sex-specific alterations in PGD2 secretion and subsequent epigenetic impairment of the differentiation potential of CPC. Causally involved is the impaired AR signaling in absence of STAT3, which reduces the expression of the PG degrading enzyme HPGD.
Abbreviations
- ANOVA
- analysis of variance
- AR
- androgen receptor
- ARVC
- arrhythmogenic right ventricular dysplasia
- BAT
- brown adipose tissue
- BMP2
- bone morphogenetic protein 2
- BMP4
- bone morphogenetic protein 4
- bpm
- beats per minute
- BW
- body weight
- CD
- cluster of differentiation
- cDNA
- complementary deoxyribonucleic acid
- CEBPA
- CCAAT/enhancer-binding protein alpha
- COX
- cyclooxygenase
- CPC
- Sca1+-cardiac progenitor cell
- DCM
- dilated cardiomyopathy
- DMEM
- Dulbecco’s Modified Eagle Medium
- DMR
- differentially methylated region
- EBF2
- early B cell factor 2
- EGF
- epidermal growth factor
- EGM-2
- endothelial cell growth medium-2
- EPAS1
- endothelial PAS domain protein 1
- EPO
- erythropoietin
- EPOR
- erythropoietin receptor
- EZH2
- enhancer of zeste homolog 2
- FABP4
- fatty acid binding protein 4
- FCS
- fetal calf serum
- FGF
- fibroblast growth factor
- FGFR2
- fibroblast growth factor receptor 2
- FITC
- fluorescein isothiocyanate
- FS
- fractional shortening
- GLUT4
- glucose transporter 4
- HBSS
- Hank’s balanced salt solution
- HPGD
- hydroxyprostaglandin-dehydrogenase-15
- HW
- heart weight
- IB4
- isolectin B4
- ICM
- ischemic cardiomyopathy
- i.p.
- intraperitoneal
- ITS
- insulin-transferrin, sodium selenite
- LV
- left ventricle
- LVEF
- left ventricular ejection fraction
- m
- month
- MACS
- magnetic-activated cell sorting
- MHC
- myosin heavy chain
- mRNA
- messenger ribonucleic acid
- NaCl
- sodium chloride
- NF
- non-failing
- PCR2
- Polycomb repressive complexe 2
- PDGFRα
- platelet-derived growth factor receptor alpha
- PG
- prostaglandin
- PPARγ2
- peroxisome proliferator-activated receptor gamma isoform 2
- PPCM
- peripartum cardiomyopathy
- PRDM16
- PR-domain containing 16
- PREF-1
- preadipocyte factor 1
- qRT-PCR
- quantitative real-time polymerase chain reaction
- rh
- recombinant human
- rmEPO
- recombinant mouse erythropoietin
- RRBS
- reduced representation bisulfite sequencing
- Sca1
- stem cell antigen-1
- SD
- standard deviation
- SDS-PAGE
- sodium dodecyl sulfate polyacrylamide gel electrophoresis
- STAT3
- signal transducer and activator of transcription 3
- STAT3-KD
- STAT3 knockdown
- UCP-1
- uncoupling protein-1
- UTR
- untranslated region
- WAT
- white adipose tissue
- WGA
- wheat germ agglutinin
- WT
- wildtype
- Zfp423
- zinc-finger protein 423
- Zfp521
- zinc-finger protein 521
- ZNF
- zinc nuclear factor