HG (30 mM) exposed PC12 cells demonstrated reduced mitochondrial complex activities and oxygen consumption rate (OCR), decreased the expressions of Sirt1, peroxisome proliferator-activated receptor coactivator-1α (PGC1α), nuclear respiratory factor-2 (NRF2), LONP1 and ATP synthase c. SRT1720 treatment (4 μM) significantly reversed these effects in hyperglycemia insulted PC12 cells but silencing the expression of LONP1 impeded this effect of SRT1720 on mitochondrial complex activities, OCR and mitochondrial membrane potential.
Recent evidence demonstrates the beneficial role of Sirtuin 1 (SIRT1), an NAD<sup>+</sup> dependant deacetylase, in improved insulin sensitivity and glucose homeostasis, linking hyperglycaemia and SIRT1 downregulation.
Furthermore, examination of the overexpression of forkhead box O1 (FOXO1), a transcription factor substrate of SIRT1, in HUVECs and db/db mice revealed that RES activated SIRT1 to restore hyperglycemia-triggered endothelial dysfunction and disturbance of angiogenesis, followed by the promotion of diabetic wound healing in a c-Myc-dependent manner.
A similar attenuation of hyperglycemia and hyperinsulinemia in wild-type mice with obesity but not in Sirt1-LKO mice could be attributed to insufficient reversal of HFD-induced mitochondrial reactive oxygen species generation in peripheral tissues in the latter.
Under hyperglycemia conditions, human umbilical vein endothelial cells (HUVECs) showed lower expression of SIRT1 and higher levels of reactive oxygen species (ROS) production.
Furthermore, we demonstrated that butein may inhibit acetylation of P53 and protect NP cells against hyperglycaemia-induced apoptosis and senescence through Sirt1 activation, as the Sirt1 inhibitor Ex527 may counteract the protective effect of butein in hyperglycaemic NP cells.
Collectively, these finds demonstrated the therapeutic potential of THC treatment to alleviate DCM mainly by attenuating hyperglycemia-induced oxidative stress and fibrosis via activating the SIRT1 pathway.
According to this results, APN can be useful in preventing renal cell damage, by affecting on the expression of mTOR and SIRT1 proteins, as well as increasing the survival of kidney cells in hyperglycaemia conditions.
Taken together, these results showed that baicalin restrained HGP via inhibiting SirT1 activity coupled with STAT3 acetylation and subsequent PGC-1α suppression, suggesting that hepatic SirT1 and STAT3 pathway may provide therapeutic advantages for the control of hyperglycemia.
It can be concluded that formononetin treatment reduces insulin resistance and attenuate hyperglycemia in type 2 diabetes which may be due to increasing expression of SIRT1 in pancreatic tissues.
In conclusion, the present study revealed that hyperglycemia promotes oxidative stress, mitochondrial dysfunction and apoptosis in HUV‑EC‑C cells, and manipulation of SIRT1 activity regulated hyperglycemia‑induced mitochondrial dysfunction and apoptosis in HUV‑EC‑C cells.
Sirtuin (SIRT1) inactivation underlies the pathogenesis of insulin resistance and hyperglycaemia-associated vascular complications, but its role in diabetic neuropathy (DN) has not been yet explored.
These data provide the first evidence of the Egt ability to interfere with endothelial senescence linked to hyperglycaemia through the regulation of SIRT1 and SIRT6 signaling, thus further strengthening the already assessed role of these two histone deacetylases in type 2 diabetes.
GDM is accompanied by leukocyte PIK3CD overexpression associated with reduced plasma LDL-C and TC levels, as well as with hyperglycaemia and elevated leukocyte SIRT1 mRNA.
We conclude that post-transcriptional stabilization of SIRT1 by HuR represses inflammation- and hyperglycaemia-induced E-selectin release and endothelial cell activation.
These findings unveil a link between PAF and SIRT1 pathways in EPCs that contributes to the deleterious effect of hyperglycaemia on the functional properties of EPCs, crucial in diabetes and peripheral vascular complications.
These findings represent a novel mechanism of vascular cell senescence induced by hyperglycemia and suggest a protective role of SIRT1 in the pathogenesis of diabetic vasculopathy.