Increasing evidence suggests a role for oxidative stress in age-related decrease in osteoblast number and function leading to the development of osteoporosis. This study was undertaken to investigate whether ghrelin, previously reported to stimulate osteoblast proliferation, counteracts tert-butyl hydroperoxide (t-BHP)-induced oxidative damage in MC3T3-E1 osteoblastic cells as well as to characterize the ghrelin receptor (GHS-R) involved in such activity. Pretreatment with ghrelin (10-7-10 -11M) significantly increased viability and reduced apoptosis of MC3T3-E1 cells cultured with t-BHP (250 μM) for three hours at the low concentration of 10-9M as shown by MTT assay and Hoechst-33258 staining. Furthermore, ghrelin prevented t-BHP-induced osteoblastic dysfunction and changes in the cytoskeleton organization evidenced by the staining of the actin fibers with Phalloidin-FITC by reducing reactive oxygen species generation. The GHS-R type 1a agonist, EP1572 (10-7-10 -11M), had no effect against t-BHP-induced cytotoxicity and pretreatment with the selective GHS-R1a antagonist, d-Lys3-GHRP-6 (10-7M), failed to remove ghrelin (10-9 M)-protective effects against oxidative injury, indicating that GHS-R1a is not involved in such ghrelin activity. Accordingly, unacylated ghrelin (DAG), not binding GHS-R1a, displays the same protective actions of ghrelin against t-BHP-induced cytotoxicity. Preliminary observations indicate that ghrelin increased the trimethylation of lys4 on histones H3, a known epigenetic mark activator, which may regulate the expression of some genes limiting oxidative damage. In conclusion, our data demonstrate that ghrelin and DAG promote survival of MC3T3-E1 cell exposed to t-BHP-induced oxidative damage. Such effect is independent of GHS-R1a and is likely mediated by a common ghrelin/DAG binding site. © 2014 Springer-Verlag.

Acylated and unacylated ghrelin protect MC3T3-E1 cells against tert-butyl hydroperoxide-induced oxidative injury: Pharmacological characterization of ghrelin receptor and possible epigenetic involvement / E. Dieci, L. Casati, F. Pagani, F. Celotti, V. Sibilia. - In: AMINO ACIDS. - ISSN 0939-4451. - 46:7(2014), pp. 1715-1725. [10.1007/s00726-014-1734-y]

Acylated and unacylated ghrelin protect MC3T3-E1 cells against tert-butyl hydroperoxide-induced oxidative injury: Pharmacological characterization of ghrelin receptor and possible epigenetic involvement

E. Dieci;L. Casati;F. Pagani;F. Celotti;V. Sibilia
2014

Abstract

Increasing evidence suggests a role for oxidative stress in age-related decrease in osteoblast number and function leading to the development of osteoporosis. This study was undertaken to investigate whether ghrelin, previously reported to stimulate osteoblast proliferation, counteracts tert-butyl hydroperoxide (t-BHP)-induced oxidative damage in MC3T3-E1 osteoblastic cells as well as to characterize the ghrelin receptor (GHS-R) involved in such activity. Pretreatment with ghrelin (10-7-10 -11M) significantly increased viability and reduced apoptosis of MC3T3-E1 cells cultured with t-BHP (250 μM) for three hours at the low concentration of 10-9M as shown by MTT assay and Hoechst-33258 staining. Furthermore, ghrelin prevented t-BHP-induced osteoblastic dysfunction and changes in the cytoskeleton organization evidenced by the staining of the actin fibers with Phalloidin-FITC by reducing reactive oxygen species generation. The GHS-R type 1a agonist, EP1572 (10-7-10 -11M), had no effect against t-BHP-induced cytotoxicity and pretreatment with the selective GHS-R1a antagonist, d-Lys3-GHRP-6 (10-7M), failed to remove ghrelin (10-9 M)-protective effects against oxidative injury, indicating that GHS-R1a is not involved in such ghrelin activity. Accordingly, unacylated ghrelin (DAG), not binding GHS-R1a, displays the same protective actions of ghrelin against t-BHP-induced cytotoxicity. Preliminary observations indicate that ghrelin increased the trimethylation of lys4 on histones H3, a known epigenetic mark activator, which may regulate the expression of some genes limiting oxidative damage. In conclusion, our data demonstrate that ghrelin and DAG promote survival of MC3T3-E1 cell exposed to t-BHP-induced oxidative damage. Such effect is independent of GHS-R1a and is likely mediated by a common ghrelin/DAG binding site. © 2014 Springer-Verlag.
Ghrelin; Ghrelin receptors; MC3T3-E1; Oxidative stress; Unacylated ghrelin
Settore BIO/14 - Farmacologia
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/249882
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