Table 1.

Alterations in the physiological mechanisms by decreased SIRT1 expression.

Effects of decreased SIRT1	Mechanism	Reference
SIRT1, OS and female infertility
Decreased Ovarian Reserve	SIRT1 regulates proliferation and apoptosis in granulosa cells (GCs) and its down-regulation is associated with a reduced ovarian reserve	Tatone C et al. (Tatone and Di Emidio, 2015)
Increase in Stress	Hindrance of modulation of stress response to oxidative stress in GCs by targeting FOXL2, a transcription factor vital for ovarian functions and maintenance.	Benayoun et al. (Benayoun et al., 2011)
Increased insulin resistance	SIRT1 improves insulin resistance by reducing oxidative stress and regulating mitochondrial biogenesis and function.	Zhang HH et al. (Zhang et al., 2015)
Dysregulation of Glucose metabolism	SIRT1 regulates hepatic glucose metabolism by interacting with and deacetylating PGC-1a, which is a main transcriptional co-activator that regulates glucose metabolism in the liver at the level of gene transcription	Rodgers JT et al. (Rodgers et al., 2005)
Increased obesity	SIRT1 decreases adiposity and lipogenesis and increases fatty acid oxidation by repressing the PPARγ, inhibiting the CRTC2 or TORC2 and deacetylating and activating the PGC-1α	Picard et al. (Bordone et al., 2006); Nemoto et al., (Nemoto et al., 2005); Kilic et al. (Kilic et al., 2015)
Increased atherosclerosis (cardiovascular disease)	SIRT 1 is a cardioprotective molecule that prevents atherosclerosis by modulating endothelial injury due to impaired nitric oxide (NO) production, inflammation, oxidative stress and regulation of autophagy.	Donato et al. (Donato et al., 2015)
Renal Injury	SIRT1 inhibits sodium reabsorption in the inner medullary collecting ducts by repressing the transcription of the epithelial sodium channel, down regulates angiotensin II type 1 receptor in vascular smooth muscle cells and also promotes the resistance of RMICs to oxidative stress and injury through its anti-oxidative properties	Zhang D et al. (Zhang et al., 2009)
Accelerated oocyte ageing	Recently, SIRT1, SIRT2 and SIRT3 have emerged as protectors of oocyte against postovulatory aging. It also delays postovulatory oocyte aging through its anti-oxidative actions and by improving mitochondrial function.	Tatone C et al. (Tatone et al., 2018a)
SIRT1, OS & Male Infertility
Decrease spermatozoa protection	SIRT1 protects spermatozoa from apoptosis. Thus, deficiency of SIRT1 leads to decrease in number of spermatozoa: 1.By ubiquitination and subsequent degradation of the transcription factor FOXO3a 2.By decreasing the caspase 3 and 9, thus reducing the caspase mediated apoptosis	Wang et al. (Wang et al., 2015); Li et al. (Li et al., 2016); Zhou et al. (Zhou et al., 2017)