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Antiapoptotic factor humanin is expressed in normal and tumoral pituitary cells and protects them from TNF-α-induced apoptosis.

Gottardo MF, Jaita G, Magri ML, Zárate S, Moreno Ayala M, Ferraris J, Eijo G, Pisera D, Candolfi M, Seilicovich A - PLoS ONE (2014)

Bottom Line: Rattin (HNr), a homologous peptide of HN expressed in several adult rat tissues, also has antiapoptotic action.HNr was localized in lactotropes and somatotropes.In summary, our results demonstrate that HNr is present in the anterior pituitary gland, its expression showing sexual dimorphism, which suggests that gonadal steroids may be involved in the regulation of HNr expression in this gland.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Investigaciones Biomédicas, Universidad de Buenos Aires-CONICET, Buenos Aires, Argentina.

ABSTRACT
Humanin (HN) is a 24-amino acid peptide with cytoprotective action in several cell types such as neurons and testicular germ cells. Rattin (HNr), a homologous peptide of HN expressed in several adult rat tissues, also has antiapoptotic action. In the present work, we demonstrated by immunocytochemical analysis and flow cytometry the expression of HNr in the anterior pituitary of female and male adult rats as well as in pituitary tumor GH3 cells. HNr was localized in lactotropes and somatotropes. The expression of HNr was lower in females than in males, and was inhibited by estrogens in pituitary cells from both ovariectomized female and orquidectomized male rats. However, the expression of HNr in pituitary tumor cells was not regulated by estrogens. We also evaluated HN action on the proapoptotic effect of TNF-α in anterior pituitary cells assessed by the TUNEL method. HN (0.5 µM) per se did not modify basal apoptosis of anterior pituitary cells but completely blocked the proapoptotic effect of TNF-α in total anterior pituitary cells, lactotropes and somatotropes from both female and male rats [corrected]. Also, HN inhibited the apoptotic effect of TNF-α on pituitary tumor cells. In summary, our results demonstrate that HNr is present in the anterior pituitary gland, its expression showing sexual dimorphism, which suggests that gonadal steroids may be involved in the regulation of HNr expression in this gland. Antiapoptotic action of HN in anterior pituitary cells suggests that this peptide could be involved in the homeostasis of this gland. HNr is present and functional in GH3 cells, but it lacks regulation by estrogens, suggesting that HN could participate in the pathogenesis of pituitary tumors.

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Ovariectomy increases anterior pituitary HNr expression.Dispersed anterior pituitary cells from SHAM and OVX rats were immunostained for HNr and analyzed by flow cytometry. Each column represents the mean ± SE (n = 4 animals per group) of (A) the percentage of HNr-positive cells, and (B) the fluorescence intensity of HNr staining (Gmean). The upper panels show representative dot plots and histograms of HNr expression in anterior pituitary cells from SHAM and OVX rats. *p<0.05, Student’s t test.
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pone-0111548-g003: Ovariectomy increases anterior pituitary HNr expression.Dispersed anterior pituitary cells from SHAM and OVX rats were immunostained for HNr and analyzed by flow cytometry. Each column represents the mean ± SE (n = 4 animals per group) of (A) the percentage of HNr-positive cells, and (B) the fluorescence intensity of HNr staining (Gmean). The upper panels show representative dot plots and histograms of HNr expression in anterior pituitary cells from SHAM and OVX rats. *p<0.05, Student’s t test.

Mentions: To evaluate whether estrogens regulate the expression of HNr in the female pituitary, we assessed by FACS HNr expression in anterior pituitary cells from SHAM-operated and OVX rats. Although ovariectomy did not modify the number of HNr-positive anterior pituitary cells, it increased HNr Gmean in these cells (Fig. 3), suggesting that gonadal hormones decrease HNr expression in anterior pituitary cells. To explore this possibility, anterior pituitary cells from OVX rats were incubated with 17β-estradiol (10−9 M). Estrogens decreased the percentage of HNr-positive cells and HNr Gmean in anterior pituitary cells (Fig. 4). The inhibitory effect of estrogens on HNr expression was not observed in the presence of the pure antagonist of estrogen receptors, ICI 182 780 (Fig. S1). However, in male rats, gonadectomy did not affect HNr expression in the anterior pituitary (Fig. S2). While DHT (10−8 M) had no effect on HNr expression in anterior pituitary cells from GNX rats, E2 inhibited its expression as we observed in female anterior pituitary cells (Fig. 5).


Antiapoptotic factor humanin is expressed in normal and tumoral pituitary cells and protects them from TNF-α-induced apoptosis.

Gottardo MF, Jaita G, Magri ML, Zárate S, Moreno Ayala M, Ferraris J, Eijo G, Pisera D, Candolfi M, Seilicovich A - PLoS ONE (2014)

Ovariectomy increases anterior pituitary HNr expression.Dispersed anterior pituitary cells from SHAM and OVX rats were immunostained for HNr and analyzed by flow cytometry. Each column represents the mean ± SE (n = 4 animals per group) of (A) the percentage of HNr-positive cells, and (B) the fluorescence intensity of HNr staining (Gmean). The upper panels show representative dot plots and histograms of HNr expression in anterior pituitary cells from SHAM and OVX rats. *p<0.05, Student’s t test.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4216097&req=5

pone-0111548-g003: Ovariectomy increases anterior pituitary HNr expression.Dispersed anterior pituitary cells from SHAM and OVX rats were immunostained for HNr and analyzed by flow cytometry. Each column represents the mean ± SE (n = 4 animals per group) of (A) the percentage of HNr-positive cells, and (B) the fluorescence intensity of HNr staining (Gmean). The upper panels show representative dot plots and histograms of HNr expression in anterior pituitary cells from SHAM and OVX rats. *p<0.05, Student’s t test.
Mentions: To evaluate whether estrogens regulate the expression of HNr in the female pituitary, we assessed by FACS HNr expression in anterior pituitary cells from SHAM-operated and OVX rats. Although ovariectomy did not modify the number of HNr-positive anterior pituitary cells, it increased HNr Gmean in these cells (Fig. 3), suggesting that gonadal hormones decrease HNr expression in anterior pituitary cells. To explore this possibility, anterior pituitary cells from OVX rats were incubated with 17β-estradiol (10−9 M). Estrogens decreased the percentage of HNr-positive cells and HNr Gmean in anterior pituitary cells (Fig. 4). The inhibitory effect of estrogens on HNr expression was not observed in the presence of the pure antagonist of estrogen receptors, ICI 182 780 (Fig. S1). However, in male rats, gonadectomy did not affect HNr expression in the anterior pituitary (Fig. S2). While DHT (10−8 M) had no effect on HNr expression in anterior pituitary cells from GNX rats, E2 inhibited its expression as we observed in female anterior pituitary cells (Fig. 5).

Bottom Line: Rattin (HNr), a homologous peptide of HN expressed in several adult rat tissues, also has antiapoptotic action.HNr was localized in lactotropes and somatotropes.In summary, our results demonstrate that HNr is present in the anterior pituitary gland, its expression showing sexual dimorphism, which suggests that gonadal steroids may be involved in the regulation of HNr expression in this gland.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Investigaciones Biomédicas, Universidad de Buenos Aires-CONICET, Buenos Aires, Argentina.

ABSTRACT
Humanin (HN) is a 24-amino acid peptide with cytoprotective action in several cell types such as neurons and testicular germ cells. Rattin (HNr), a homologous peptide of HN expressed in several adult rat tissues, also has antiapoptotic action. In the present work, we demonstrated by immunocytochemical analysis and flow cytometry the expression of HNr in the anterior pituitary of female and male adult rats as well as in pituitary tumor GH3 cells. HNr was localized in lactotropes and somatotropes. The expression of HNr was lower in females than in males, and was inhibited by estrogens in pituitary cells from both ovariectomized female and orquidectomized male rats. However, the expression of HNr in pituitary tumor cells was not regulated by estrogens. We also evaluated HN action on the proapoptotic effect of TNF-α in anterior pituitary cells assessed by the TUNEL method. HN (0.5 µM) per se did not modify basal apoptosis of anterior pituitary cells but completely blocked the proapoptotic effect of TNF-α in total anterior pituitary cells, lactotropes and somatotropes from both female and male rats [corrected]. Also, HN inhibited the apoptotic effect of TNF-α on pituitary tumor cells. In summary, our results demonstrate that HNr is present in the anterior pituitary gland, its expression showing sexual dimorphism, which suggests that gonadal steroids may be involved in the regulation of HNr expression in this gland. Antiapoptotic action of HN in anterior pituitary cells suggests that this peptide could be involved in the homeostasis of this gland. HNr is present and functional in GH3 cells, but it lacks regulation by estrogens, suggesting that HN could participate in the pathogenesis of pituitary tumors.

Show MeSH
Related in: MedlinePlus