Upregulation of SIRT1 by Evodiamine activates PI3K/AKT pathway and blocks intervertebral disc degeneration

Kuai, Jianbo; Zhang, Na

doi:10.3892/mmr.2022.12781

Cited by 12 publications

(13 citation statements)

References 35 publications

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“…However, blocking AKT pathway did not abolish the beneficial effects of NSC45586 on NP cell anabolism and NP marker expression. It is possible that AKT pathway might be involved in other cellular activities, such as cell proliferation, inflammatory responses, and senescence, as reported in previous studies 41–43 . Interestingly, pharmacological inhibition of PHLPP function increased FOXO1 expression and promoted NP cell anabolism and NP marker expression.…”

Section: Discussionsupporting

confidence: 60%

Differential efficacy of two small molecule PHLPP inhibitors to promote nucleus Pulposus cell health

Zhang,

Gordon,

Joseph

et al. 2023

JOR Spine

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BackgroundIntervertebral disc (IVD) degeneration is associated with chronic back pain. We previously demonstrated that the phosphatase pleckstrin homology domain and leucine‐rich repeat protein phosphatase (PHLPP) 1 was positively correlated with IVD degeneration and its deficiency decelerated IVD degeneration in both mouse IVDs and human nucleus pulposus (NP) cells. Small molecule PHLPP inhibitors may offer a translatable method to alleviate IVD degeneration. In this study, we tested the effectiveness of the two PHLPP inhibitors NSC117079 and NSC45586 in promoting a healthy NP phenotype.MethodsTail IVDs of 5‐month‐old wildtype mice were collected and treated with NSC117079 or NSC45586 under low serum conditions ex vivo. Hematoxylin & eosin staining was performed to examine IVD structure and NP cell morphology. The expression of KRT19 was analyzed through immunohistochemistry. Cell apoptosis was assessed by TUNEL assay. Human NP cells were obtained from patients with IVD degeneration. The gene expression of KRT19, ACAN, SOX9, and MMP13 was analyzed via real time qPCR, and AKT phosphorylation and the protein expression of FOXO1 was analyzed via immunoblot.ResultsIn a mouse IVD organ culture model, NSC45586, but not NSC117079, preserved vacuolated notochordal cell morphology and KRT19 expression while suppressing cell apoptosis, counteracting the degenerative changes induced by serum deprivation, especially in males. Likewise, in degenerated human NP cells, NSC45586 increased cell viability and the expression of KRT19, ACAN, and SOX9 and reducing the expression of MMP13, while NSC117079 treatment only increased KRT19 expression. Mechanistically, NSC45586 treatment increased FOXO1 protein expression in NP cells, and inhibiting FOXO1 offset NSC45586‐induced regenerative potential, especially in males.ConclusionsOur study indicates that NSC45586 was effective in promoting NP cell health, especially in males, suggesting that PHLPP plays a key role in NP cell homeostasis and that NSC45586 might be a potential drug candidate in treating IVD degeneration.

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Section: Discussionsupporting

confidence: 60%

Differential efficacy of two small molecule PHLPP inhibitors to promote nucleus Pulposus cell health

Zhang,

Gordon,

Joseph

et al. 2023

JOR Spine

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“…PHLPP1 is known to directly dephosphorylate and promote apoptotic pathways such as Mst1, and inactive pro‐survival pathways such as AKT, PKC and p70S6 kinase 24–26,45 . One of the key regulators in IVD cell apoptosis is AKT signaling 46,47 . Our in vitro findings showed that PHLPP1 knockdown increased AKT phosphorylation in human degenerated NP cells while inhibiting AKT activity did not reverse the effects of PHLPP1 knockdown on KRT19 gene expression.…”

Section: Discussionmentioning

confidence: 60%

“…[24][25][26]45 One of the key regulators in IVD cell apoptosis is AKT signaling. 46,47 Our in vitro findings showed that PHLPP1 knockdown increased AKT phosphorylation in human degenerated NP cells while inhibiting AKT activity did not reverse the effects of PHLPP1 knockdown on KRT19 gene expression. It is possible that AKT signaling is not involved in promoting NP phenotype, but regulating cell survival in the IVD.…”

Section: Phlpp1 Knockdown Increased Protein Levels Of Krt19 Via Foxo1...mentioning

confidence: 80%

PHLPP1 deficiency protects against age‐related intervertebral disc degeneration

et al. 2022

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Background Intervertebral disc (IVD) degeneration is strongly associated with low back pain and is highly prevalent in the elderly population. Hallmarks of IVD degeneration include cell loss and extracellular matrix degradation. The PH domain leucine‐rich‐repeats protein phosphatase (PHLPP1) is highly expressed in diseased cartilaginous tissues where it is linked to extracellular matrix degradation. This study explored the ability of PHLPP1 deficiency to protect against age‐related spontaneous IVD degeneration. Methods Lumbar IVDs of global Phlpp1 knockout (KO) and wildtype (WT) mice were collected at 5 months (young) and 20 months (aged). Picrosirius red–alcian blue staining (PR‐AB) was performed to examine IVD structure and histological score. The expression of aggrecan, ADAMTS5, KRT19, FOXO1 and FOXO3 was analyzed through immunohistochemistry. Cell apoptosis was assessed by TUNEL assay. Human nucleus pulposus (NP) samples were obtained from patients diagnosed with IVD degeneration. PHLPP1 knockdown in human degenerated NP cells was conducted using small interfering RNA (siRNA) transfection. The expression of PHLPP1 regulated downstream targets was analyzed via immunoblot and real time quantitative PCR. Results Histological analysis showed that Phlpp1 KO decreased the prevalence and severity of age‐related IVD degeneration. The deficiency of PHLPP1 promoted the increased expression of NP phenotypic marker KRT19, aggrecan and FOXO1, and decreased levels of ADMATS5 and cell apoptosis in the NP of aged mice. In degenerated human NP cells, PHLPP1 knockdown induced FOXO1 protein levels while FOXO1 inhibition offset the beneficial effects of PHLPP1 knockdown on KRT19 gene and protein expression. Conclusions Our findings indicate that Phlpp1 deficiency protected against NP phenotypic changes, extracellular matrix degradation, and cell apoptosis in the process of IVD degeneration, probably through FOXO1 activation, making PHLPP1 a promising therapeutic target for treating IVD degeneration.

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“…For example, SIRT1, which is the most studied mammalian sirtuin isoform, mediates deacetylation of Akt to enhance the binding of Akt and PDK1 to PIP3 to enhance IGF-1 signalling in HEK293T cells 39. Furthermore, activation of SIRT1 by several compounds has been shown to attenuate lipopolysaccharide and IL-1β-induced inhibition of Akt phosphorylation to repress inflammatory mediators, enhance cell survival and promote the synthesis of ECM components such as aggrecan, collagen II and SOX9 in nucleus pulposus cells 40 41. Although data demonstrating a direct role for SIRT6 to activate IGF-1 signalling are sparse, recent evidence in tumour cell lines demonstrates that overexpression of SIRT6 can deacetylate and phosphorylate Akt to enhance activation of the downstream apoptosis inhibitor protein, XIAP, and promote cell survival 42.…”

Section: Discussionmentioning

confidence: 99%

Cartilage-specificSirt6deficiency represses IGF-1 and enhances osteoarthritis severity in mice

Collins,

Kim,

Coleman

et al. 2023

Ann Rheum Dis

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ObjectivesPrior studies noted that chondrocyte SIRT6 activity is repressed in older chondrocytes rendering cells susceptible to catabolic signalling events implicated in osteoarthritis (OA). This study aimed to define the effect ofSirt6deficiency on the development of post-traumatic and age-associated OA in mice.MethodsMale cartilage-specificSirt6-deficient mice andSirt6intact controls underwent destabilisation of the medial meniscus (DMM) or sham surgery at 16 weeks of age and OA severity was analysed at 6 and 10 weeks postsurgery. Age-associated OA was assessed in mice aged 12 and 18 months of age. OA severity was analysed by micro-CT, histomorphometry and scoring of articular cartilage structure, toluidine blue staining and osteophyte formation. SIRT6-regulated pathways were analysed in human chondrocytes by RNA-sequencing, qRT-PCR and immunoblotting.ResultsSirt6-deficient mice displayed enhanced DMM-induced OA severity and accelerated age-associated OA when compared with controls, characterised by increased cartilage damage, osteophyte formation and subchondral bone sclerosis. In chondrocytes, RNA-sequencing revealed thatSIRT6depletion significantly repressed cartilage extracellular matrix (eg,COL2A1) and anabolic growth factor (eg, insulin-like growth factor-1 (IGF-1)) gene expression. Gain-of-function and loss-of-function studies in chondrocytes demonstrated that SIRT6 depletion attenuated, whereas adenoviral overexpression or MDL-800-inducedSIRT6activation promoted IGF-1 signalling by increasing Aktser473phosphorylation.ConclusionsSIRT6 deficiency increases post-traumatic and age-associated OA severity in vivo. SIRT6 profoundly regulated the pro-anabolic and pro-survival IGF-1/Akt signalling pathway and suggests that preserving the SIRT6/IGF-1/Akt axis may be necessary to protect cartilage from injury-associated or age-associated OA. Targeted therapies aimed at increasing SIRT6 function could represent a novel strategy to slow or stop OA.

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Upregulation of SIRT1 by Evodiamine activates PI3K/AKT pathway and blocks intervertebral disc degeneration

Cited by 12 publications

References 35 publications

Differential efficacy of two small molecule PHLPP inhibitors to promote nucleus Pulposus cell health

Differential efficacy of two small molecule PHLPP inhibitors to promote nucleus Pulposus cell health

PHLPP1 deficiency protects against age‐related intervertebral disc degeneration

Cartilage-specificSirt6deficiency represses IGF-1 and enhances osteoarthritis severity in mice

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