Interrelationships between sirtuin 1 and transcription factors p53 and NF-κB (p50/p65) in the control of ovarian cell apoptosis and proliferation

Abstract

The roles of the mTOR system enzyme sirtuin 1 (SIRT1), the transcription factor p53 and the nuclear factor kappaB (NF-κB) and their interrelationships in the control of ovarian function have not been well studied. We examine, in vitro, the involvement of SIRT1, p53 and the p65 and p50 subunits of NFκB and their interrelationships in the control of the apoptosis and proliferation of porcine ovarian granulosa cells. Monolayers of primary granulosa cells were transfected with cDNA constructs encoding SIRT1, p53, p65 or p50 alone or were co-transfected with gene constructs for SIRT1 together with p53, p65 or p50. The accumulation of SIRT1, markers of proliferation (mitogen-activated protein kinase or extracellular-signal-regulated kinases 1,2) and a marker of apoptosis (caspase 3) was detected by immunocytochemistry. Transfection of cells with a SIRT1 gene construct alone promoted the accumulation of SIRT1 and decreased the accumulation of proliferation markers but did not affect the marker of apoptosis. Transfection of cells with gene constructs encoding p53, p50 or p65 decreased the expression of proliferation markers but not the apoptosis marker. Co-transfection of cells with SIRT1 cDNA changed the action of p65 on cell proliferation from inhibitory to stimulatory. SIRT1 overexpression induced the pro-apoptotic action of p53 and p50 but not of p65 constructs. Thus, SIRT1, p53 and NF-κB are involved in the control of both the proliferation and the apoptosis of ovarian cells. These novel data on the cross-talk between the mTOR/SIRT1 system and the transcription factors p53 and NF-κB show both the inhibitory (proliferation) and stimulatory (apoptosis) influences of SIRT1 on transcription factor action in ovarian cells.

The mTOR System Can Affect Basic Ovarian Cell Functions and Mediate the Effect of Ovarian Hormonal Regulators

“…In the present study, no effect of either PF 046 or WYE 687 on porcine granulosa cell apoptosis was observed as well. Moreover, transfection with SIRT1 gene construct did not alter the apoptosis of porcine granulosa cells in our previous experiment (Sirotkin et al, 2014). However, the inhibition of mTORC1/2 by NVP-BEZ235 and DS-7423 increased the apoptosis of human ovarian cancer cells (Santiskulvong et al, 2011;Kashiyama et al, 2014), indicating the possible involvement of mTOR in the control of at least human ovarian cancer cells.…”

“…The involvement of the mTOR system in both the up-and down-regulation of ovarian cell proliferation is supported by previous experiments that manipulated SIRT1, a physiological inhibitor of the mTOR system. The transfection of porcine granulosa cells with an SIRT1 gene construct was able to either stimulate or inhibit the cell proliferation of these cells (Pavlova et al, 2013;Sirotkin et al, 2014). The SIRT1 inhibition by sirtinol resulted in the reduced proliferation of a human ovarian granulosa-like tumour cell line (Benayoun et al, 2011).…”

“…For example, SIRT1 inhibition by sirtinol resulted in the reduced proliferation of a human ovarian granulosa-like tumour cell line (Benayoun et al, 2011). Transfection with a SIRT1 gene construct stimulated or inhibited proliferation, did not affect apoptosis and stimulated the P4 and IGF-1 release by porcine granulosa cells (Pavlova et al, 2013;Sirotkin et al, 2014). Taken together, these data suggest that mTOR/SIRT1 signalling could play an important role in the regulation of ovarian cell proliferation, apoptosis and the resulting ovarian follicular growth, development and atresia.…”

Follicle aging: a question of stress?

“…Recent data reported that the SIRT1/NF-kB system mediates FSH activity on progesterone and IGF-1 release (34). Thus GC fate may depend on the balance between inhibitory and stimulatory influences on SIRT1 (35). Moreover, stimulation of SIRT1 by resveratrol provides evidence for direct involvement of SIRT1 in the upregulation of ovarian hormone secretion (34).…”

The Role and Application of Sirtuins and mTOR Signaling in the Control of Ovarian Functions

“…These observations suggest that SIRT1 can promote ovarian functions via activation of the GnRH–gonadotropin–ovarian gonadotropin receptor axis, although direct action of SIRT1 on the ovarian cells is also evident. Transfection with a SIRT1 gene construct stimulated proliferation (but not apoptosis), progesterone, testosterone, and IGF-1 release by cultured porcine granulosa cells [23,24] and developmental capacity of mouse and human oocytes [25]. Either FSH or OT additions increased the SIRT1 accumulation in cultured porcine ovarian granulosa cells, while IGF-I addition decreased it.…”