Probes for INS

Background The adult mammalian heart responds to cardiac injury by formation of persistent fibrotic scar that eventually leads to heart failure. In contrast, the neonatal mammalian heart reacts to injury by the development of transient fibrotic tissue that is eventually replaced by regenerated cardiomyocytes. How fibrosis occurs in the neonatal mammalian heart remains unknown. To start elucidating the molecular underpinnings of neonatal cardiac fibrosis, we investigated Wnt signaling in the neonatal heart after cryoinjury.

Methods and Results Using expression of the Wnt target gene Axin2 as an indicator of Wnt/β‐catenin signaling activation, we discovered that epicardial cells in the ventricles are responsive to Wnt in the uninjured neonatal heart. Lineage‐tracing studies of these Wnt‐responsive epicardial cells showed that they undergo epithelial‐to‐mesenchymal transition and infiltrate into the subepicardial space and exhibit fibroblast phenotypes after injury. In addition, we showed that—similar to adult ischemic injury—neonatal cryoinjury results in activation of Wnt signaling in cardiac fibroblasts near injured areas. Furthermore, through in situ hybridization of all 19 Wnt ligands in injured neonatal hearts, we observed upregulation of Wnt ligands (Wnt2b, Wnt5a, and Wnt9a) that had not been implicated in the adult cardiac injury response.

Conclusions These results demonstrate that cryoinjury in neonatal heart leads to the formation of fibrotic tissue that involves Wnt‐responsive epicardial cells undergoing epithelial‐to‐mesenchymal transition to give rise to fibroblasts and activation of Wnt signaling in resident cardiac fibroblasts.

CONTEXT:

FSH receptor (FSHR), besides being expressed in gonads, is also expressed in some extragonadal tissues at low levels.

OBJECTIVE:

We examined the functional expression of FSHR in different types of endometriotic lesions.

DESIGN:

Extensive studies were carried out to detect functional FSHR expression and FSH-stimulated estrogen production in ovarian endometriomas and recto-vaginal endometriotic nodules (RVEN). Normal endometrium, ovary, and myometrium tissues from nonpregnant cycling women served as controls.

SETTINGS:

This laboratory-based study was carried out on tissue specimens from patients with endometriosis and healthy donors.

RESULTS:

Endometriotic lesions and normal secretory-phase endometrium showed FSHR expression at both mRNA and protein level. RVEN and ovarian endometrioma demonstrated up-regulated CYP19A1, dependent on the activation of CYP19A1 proximal promoter II. Estrogen receptor-β (ESR2) expression was significantly increased in RVEN vs normal endometrium. Recombinant human FSH stimulation of RVEN explants significantly increased estradiol production and CYP19A1 and ESR2 expression. FSHR was up-regulated in recombinant human FSH-stimulated endometrial and decidualized stromal cells with increased CYP19A1 expression.

CONCLUSIONS:

We described a novel functional FSHR expression, where FSH-stimulated CYP19A1 expression and estrogen production in RVEN are demonstrated. This locally FSH-induced estrogen production may contribute to the pathology, development, progression, and severity of RVEN.