Protective effects of pyrroloquinoline quinone against oxidative stress-induced cellular senescence and inflammation in human renal tubular epithelial cells via Keap1/Nrf2 signaling pathway
Graphical abstract
Introduction
Diabetic nephropathy (DN) is one of the most common microvascular complications of diabetes mellitus [[1], [2], [3]]. Various studies have illustrated that high glucose (HG) increases the production of intracellular ROS and aggravates oxidative stress, thus leads to apoptosis, cellular senescence, inflammation, fibrosis and other damages of renal tubular epithelial cells [[4], [5], [6], [7]]. Especially, oxidative stress-induced cellular senescence and inflammation are important biological events of renal tubular cells in DN [[8], [9], [10], [11]]. Therefore, early intervention and treatment of renal tubular cell senescence and inflammation may effectively delay the development of DN.
Pyrroloquinoline quinone (PQQ) is an organic molecule as the third redox coenzyme following nicotinamides and flavines. PQQ is water-soluble, and the chemical properties are similar to the combined attributes of ascorbic acid and vitamin B6 [12]. Previous researches have demonstrated that PQQ has multiple physiological functions, including neural and cardiovascular protection [[13], [14], [15]], the promotion of growth and reproduction [[16], [17], [18]], and as an antioxidant to protect the cells from oxidative stress-induced damages [[19], [20], [21]]. In recent years, PQQ has become increasingly studied with its role in inflammation and cellular senescence [22,23]. Our recent studies have found that PQQ has protective effects against HG-induced oxidative stress damage and apoptosis in vitro model of diabetic nephropathy. PQQ (10 nM–10,000 nM) significantly increased the cell viability at 48 h under HG environment, especially in 100 nM concentration [24]. However, whether PQQ has the effect of anti-inflammation and anti-senescence in HK-2 cells remains unclear.
Nuclear factor-E2-related factor 2 (Nrf2), a key modulator of redox balance and signaling, which plays an important role in defending against oxidative stress damage and regulating antioxidant genes [25]. Previous studies have suggested that Keap1/Nrf2/ARE signaling pathway plays a critical role in delaying the progression of DN. Evidence suggests that Nrf2 may also play an important role in the regulation of inflammation and senescence [[26], [27], [28], [29]]. In addition, Nrf2 is reported to be involved in suppression of pro-inflammatory situation via regulation of NF-kB signaling pathways [29,30]. Does PQQ affect the activity of Keap1/Nrf2 pathway in HK-2 cells? Whether PQQ exerts anti-oxidative stress, anti-inflammation and anti-aging effects through the Keap1/Nrf2 pathway remains unclear.
In the present study, we investigated the anti-inflammation and anti-senescence effect of PQQ in HK-2 cells under HG environment for 48 h. The effect of PQQ on the activity of Keap1/Nrf2 pathway was also further studied. The results indicated that PQQ attenuated oxidative stress-induced cellular senescence and inflammation in HK-2 cells. The protective effect of PQQ was mediated by Keap1/Nrf2 pathway.
Section snippets
Chemicals and reagents
FBS and DMEM were purchased from Life Technologies BRL (Gaithersburg, MD). d-glucose, penicillin, streptomycin and pyrroloquinoline quinone (PQQ) were obtained from Sigma (St. Louis, Mo, USA). Antibodies for P16, P21, Nrf2, HO-1, NQO1, CAT, GPx-3, GST, Keap1 and Histone H3 were obtained from Abcam (Cambridge, UK). Antibodies for β-actin and SOD2 were purchased from Proteintech (Chicago, USA). Reverse Transcription System, qPCR Master Mix were purchased from Vazyme (New Jersey, USA). The
PQQ inhibited HG-induced inflammation in HK-2 cells
In order to study whether PQQ could inhibit HG-induced inflammation in HK-2 cells, we tested the protein expression of IL-1β, TNF-α and NF-κB by western blot. As illustrated in Fig. 1A-B, the protein expression of IL-1β, TNF-α and NF-κB were significantly increased after HG stimulation for 48 h. However, PQQ treatment inhibited HG-induced secretion of these inflammatory cytokines (P < 0.05). These findings indicated that PQQ inhibited HG-induced inflammation in HK-2 cells.
PQQ inhibited HG-induced cellular senescence in HK-2 cells
Previous studies have
Discussion
The results suggest that PQQ has protective effects against HG-induced inflammation and cellular senescence in HK-2 cells. The protective effects of PQQ are associated with inhibition of ROS generation and upregulating the level of antioxidants. In this study, we also illustrate that PQQ could affect the activity of Keap1/Nrf2 pathway, promote the translocation of Nrf2 to nucleus and upregulate the protein expression downstream pathway of Keap1/Nrf2 signaling pathway. PQQ achieves the
Conflicts of interest
The authors declare no conflict of interest.
Acknowledgement
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
References (44)
- et al.
Neuroprotection by pyrroloquinoline quinone (PQQ) in reversible middle cerebral artery occlusion in the adult rat
Brain Res.
(2006) - et al.
Physiological importance of quinoenzymes and the O-quinone family of cofactors
J. Nutr.
(2000) - et al.
Dietary pyrroloquinoline quinone: growth and immune response in BALB/c mice
J. Nutr.
(1994) - et al.
Pyrroloquinoline quinone modulates mitochondrial quantity and function in mice
J. Nutr.
(2006) - et al.
Pyrroloquinoline quinine protects HK-2 cells against high glucose-induced oxidative stress and apoptosis through Sirt3 and PI3K/Akt/FoxO3a signaling pathway
Biochem. Bioph. Res. Co.
(2019) - et al.
Protective roles of NRF2 signaling pathway in cobalt chloride-induced hypoxic cytotoxicity in human HaCaT keratinocytes
Toxicol. Appl. Pharm.
(2018) - et al.
Epigallocatechin gallate potentially abrogates fluoride induced lung oxidative stress, inflammation via Nrf2/Keap1 signaling pathway in rats: an in-vivo and in-silico study
Int. Immunopharmacol.
(2016) - et al.
Nrf2 signaling pathway: pivotal roles in inflammation
Bba.-Mol. Basis Dis.
(2017) - et al.
High glucose-induced reactive oxygen species generation promotes sternness in human adipose-derived stem cells
Cytotherapy
(2016) - et al.
Ellagic acid, an NF-kappa B inhibitor, ameliorates renal function in experimental diabetic nephropathy
Chem. Biol. Interact.
(2014)
Pyrroloquinoline quinone preserves mitochondrial function and prevents oxidative injury in adult rat cardiac myocytes
Biochem. Bioph. Res. Co.
N-Acetylcysteine ameliorates cisplatin-induced renal senescence and renal interstitial fibrosis through sirtuin1 activation and p53 deacetylation
Free Radic. Biol. Med.
Pyrroloquinoline quinone stimulates mitochondrial biogenesis through cAMP response element-binding protein phosphorylation and increased PGC-1alpha expression
J. Biol. Chem.
Diabetic nephropathy: from mechanisms to rational therapies
Minerva Med.
Current concepts in the management of diabetic nephropathy
Neth. J. Med.
A glimpse of various pathogenetic mechanisms of diabetic nephropathy
Annu. Rev. Pathol-Mech.
Oxidative stress in diabetic nephropathy
Curr. Med. Chem.
Biochemistry and molecular cell biology of diabetic complications
Nature
Mangiferin attenuates diabetic nephropathy by inhibiting oxidative stress mediated signaling Cascade, TNF alpha related and mitochondrial dependent apoptotic pathways in streptozotocin-induced diabetic rats
PLoS One
Resveratrol improves oxidative stress and protects against diabetic nephropathy through normalization of Mn-SOD dysfunction in AMPK/SIRT1-independent pathway
Diabetes
Accelerated senescence in the kidneys of patients with type 2 diabetic nephropathy
Am. J. Physiol.-Renal.
Four faces of cellular senescence
J. Cell Biol.
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