SIRT3 mitigates intervertebral disc degeneration by delaying oxidative stress‐induced senescence of nucleus pulposus cells

Abstract

Senescence of nucleus pulposus (NP) cells (NPC) is a major cause of intervertebral disc degeneration (IVDD), so delay NPC senescence may be beneficial for mitigating IVDD. We studied the effect and mechanism of silent information regulator 2 homolog 3 (SIRT3) on NPC senescence in vivo and in vitro. First, we observed SIRT3 expression in normal and degenerated NPC with immunohistochemical and immunofluorescence staining. Second, using SIRT3 lentivirus transfection, reactive oxygen species probe, senescence-associated β-galactosidase staining, polymerase chain reaction, and western blot to observe the oxidative stress, senescence, and degeneration degree among groups. Subsequently, pretreatment with adenosine monophosphate-activated protein kinase (AMPK) agonists and inhibitors, observing oxidative stress, senescence, and degeneration degree among groups. Finally, the IVDD model was constructed and divided into Ctrl, Vehicle, LV-shSIRT3, and LV-SIRT3 groups. X-ray and magnetic resonance imaging scans were performed on rat's tails after 1 week; hematoxylin and eosin and safranin-O staining were used to evaluate the degree of IVDD; immunofluorescence staining was used to observe SIRT3 expression; immunohistochemical staining was used to observe oxidative stress, senescence, and degeneration degree of NP. We found that SIRT3 expression is reduced in degenerated NP tissues but increased in H 2 O 2 -induced NPC. Moreover, SIRT3 upregulation decreased oxidative stress, delayed senescence, and degeneration of NPC. In addition, activation of the AMPK/PGC-1α pathway can partially mitigate the NPC oxidative stress, senescence, and degeneration caused by SIRT3 knockdown. The study in vivo revealed that local SIRT3 overexpression can significantly reduce oxidative stress and ECM degradation of NPC, delay NPC senescence, thereby mitigating IVDD. In summary, SIRT3 mediated by the AMPK/PGC-1α pathway mitigates IVDD by delaying oxidative stress-induced NPC senescence.

Apigenin Alleviates Intervertebral Disc Degeneration via Restoring Autophagy Flux in Nucleus Pulposus Cells

“…The overexpression of ROS seriously harms cell homeostasis and leads to the accumulation of damaged DNA and dysfunctional mitochondria, especially in degenerative diseases with weak antioxidant defense mechanisms (Grishko et al, 2009). Continuous release of ROS leads to oxidative stress, creating cell apoptosis and premature senescence, and ultimately leading to cell death (Lin et al, 2021). In this study, TBHP was selected as an ROS donor to create an oxidative stress condition in vitro study.…”

Urolithin a alleviates oxidative stress-induced senescence in nucleus pulposus-derived mesenchymal stem cells through SIRT1/PGC-1α pathway

“…H 2 O 2 is commonly used to induce oxidative damage in mechanistic studies of IDD[ 20 , 22 ]. The inflammation, apoptosis and senescence of NP cells and the apoptosis and senescence of NPMSCs are important pathological models for exploring IDD, which can all be induced by H 2 O 2 treatment[ 23 - 26 ]. In our previous study, we confirmed that H 2 O 2 treatment could decrease the viability of NPMSCs in a dose- and concentration-dependent manner, and a concentration of 80 μM for 6 h could be used as a suitable concentration in vitro [ 20 ].…”

AMPK as a Potential Therapeutic Target for Intervertebral Disc Degeneration

“…Through the upregulation of mitochondrial antioxidation signals as well as the enhancement of mitochondrial dynamics and mitophagy, the activation of AMPK-PGC-1α-SIRT3 pathway suppresses mitochondrial apoptosis and senescence in rat NP cells exposed to TBHP ( Wang et al, 2018 ). AMPK-induced activation of PGC-1α-SIRT3 pathway can also inhibit the secretion of pro-inflammatory cytokines, including IL-1β and IL-6, and relieve the imbalance between the synthesis and degradation of ECM in rat NP cells stimulated by oxidative damage ( Lin et al, 2021 ). Acetyl-CoA carboxylase (ACC) is widely known as an important intermediate metabolite in fatty acid metabolism.…”