bims-nadaut 2023-08-27 papers

bims-nadaut

Biomed News

on NAD and autophagy

Issue of 2023‒08‒27
eleven papers selected by
Niall Wilson, Newcastle University

The Role of Poly(ADP-ribose) Polymerase 1 in Nuclear and Mitochondrial Base Excision Repair.
Resveratrol‑mediated activation of SIRT1 inhibits the PERK‑eIF2α‑ATF4 pathway and mitigates bupivacaine‑induced neurotoxicity in PC12 cells.
Sirtuin 1 Expression in Canine Mammary Tumors: A Pilot Study.
Protective effect of Xinmai'an tablets via mediation of the AMPK/SIRT1/PGC-1α signaling pathway on myocardial ischemia-reperfusion injury in rats.
PPARδ activation improves cardiac mitochondrial homeostasis in desmin deficient mice but does not alleviate systolic dysfunction.
Poly(ADP-Ribose) Polymerase-1 Lacking Enzymatic Activity Is Not Compatible with Mouse Development.
Nicotinamide Riboside Improves Stemness of Human Adipose-Derived Stem Cells and Inhibits Terminal Adipocyte Differentiation.
Mitochondrial Transfer Between Cell Crosstalk - An Emerging Role in Mitochondrial Quality Control.
SIRT6 deficiency in endothelial cells exacerbates oxidative stress by enhancing HIF1α accumulation and H3K9 acetylation at the Ero1α promoter.
NLRP3 inflammasome-mediated pyroptosis involvement in cadmium exposure-induced cognitive deficits via the Sirt3-mtROS axis.
Increased SIRT3 combined with PARP inhibition rescues motor function of SBMA mice.

Biomolecules. 2023 Jul 31. pii: 1195. [Epub ahead of print]13(8):

The Role of Poly(ADP-ribose) Polymerase 1 in Nuclear and Mitochondrial Base Excision Repair.

Geoffrey K Herrmann, Y Whitney Yin.

  Poly(ADP-ribose) (PAR) Polymerase 1 (PARP-1), also known as ADP-ribosyl transferase with diphtheria toxin homology 1 (ARTD-1), is a critical player in DNA damage repair, during which it catalyzes the ADP ribosylation of self and target enzymes. While the nuclear localization of PARP-1 has been well established, recent studies also suggest its mitochondrial localization. In this review, we summarize the differences between mitochondrial and nuclear Base Excision Repair (BER) pathways, the involvement of PARP-1 in mitochondrial and nuclear BER, and its functional interplay with other BER enzymes.

Keywords:  DNA repair; PARP-1; nuclear and mitochondrial localization

DOI:  https://doi.org/10.3390/biom13081195
Exp Ther Med. 2023 Sep;26(3): 433

Resveratrol‑mediated activation of SIRT1 inhibits the PERK‑eIF2α‑ATF4 pathway and mitigates bupivacaine‑induced neurotoxicity in PC12 cells.

Yunpeng Luo, Na Hu, Yang Zhao, Jian Lai, Xi Luo, Jingchen Liu.

  Endoplasmic reticulum (ER) stress and apoptosis play significant roles in the development of neurotoxicity caused by bupivacaine (BUP). By activating sirtuin 1 (SIRT1), resveratrol (RSV) can regulate various cellular processes associated with anti-oxidative stress, anti-apoptosis and anti-inflammatory responses, thereby exerting neuroprotective effects. However, it remains unknown whether the activation of SIRT1 by RSV is able to attenuate BUP-induced ER stress and apoptosis. Therefore, the present study aimed to explore the effect of RSV on BUP-induced cytotoxicity in PC12 cells and the underlying mechanism. Cell Counting Kit-8 assays, flow cytometry and inverted phase-contrast microscopy were used to assess the viability, apoptosis rate and morphological changes of the cells, respectively. Western blotting and immunofluorescence staining were used to analyze the levels of SIRT1, the apoptosis-related proteins Bax, Bcl-2 and cleaved caspase-3, the ER stress-related proteins glucose-regulated protein 78, caspase-12 and CHOP, and the protein kinase RNA-like ER kinase (PERK)-eukaryotic translation initiation factor 2 α (eIF2α)-activating transcription factor 4 (ATF4) pathway-associated proteins phosphorylated (p)-PERK, PERK, p-eIF2α, eIF2α and ATF4. The results revealed that BUP induced cell apoptosis and decreased cell viability, accompanied by the downregulation of SIRT1. However, RSV restored SIRT1 protein expression, downregulated the expression of the pro-apoptotic protein Bax, upregulated the expression of the anti-apoptotic protein Bcl-2, decreased the apoptosis rate of the cells and increased cell viability. Furthermore, the anti-apoptotic effects exhibited by RSV were associated with inhibition of the PERK-eIF2α-ATF4 pathway of ER stress. However, the protective effect of RSV was significantly mitigated by the SIRT1 inhibitor EX527. These results indicate that the activation of SIRT1 by RSV alleviates BUP-induced PC12 cell ER stress and apoptosis via regulation of the PERK-eIF2α-ATF4 pathway. These findings offer insights into the molecular mechanism underlying BUP-induced apoptosis and suggest the potential of RSV as a therapeutic agent against the neurotoxicity caused by BUP.

Keywords:  PERK-eIF2α-ATF4 signaling pathway; bupivacaine; resveratrol; sirtuin 1

DOI:  https://doi.org/10.3892/etm.2023.12132
Animals (Basel). 2023 Aug 13. pii: 2609. [Epub ahead of print]13(16):

Sirtuin 1 Expression in Canine Mammary Tumors: A Pilot Study.

Mariafrancesca Sgadari, Nunzio Antonio Cacciola, Karen Power, Manuela Martano, Brunella Restucci.

  Sirtuin 1 (SIRT1) is a protein involved in aging, cell protection, and energy metabolism in mammals. Recently, SIRT1 has been intensively studied in medical oncology, but the role of SIRT1 is still controversial, as it has been proposed as both an oncogene and a tumor suppressor. The aim of this study is to investigate the expression of SIRT1 by immunohistochemistry in canine mammary tissues, and by Western blot and immunofluorescence analysis in different canine mammary cell lines. Our results showed a decrease in SIRT1 expression from normal mammary gland tissue, and from benign and well-differentiated malignant tumors (G1) to less differentiated ones (G2-G3). Furthermore, a shift in the subcellular localization of SIRT1 from the nucleus to the cytoplasm was observed in less differentiated malignant tumors. However, further studies are needed to investigate the subcellular localization of SIRT1 in canine cancer cells and the role it may play in oncogenesis in animals.

Keywords:  canine mammary tumors; culture cells; sirtuin family; veterinary oncology

DOI:  https://doi.org/10.3390/ani13162609
Phytomedicine. 2023 Aug 16. pii: S0944-7113(23)00395-1. [Epub ahead of print]120 155034

Protective effect of Xinmai'an tablets via mediation of the AMPK/SIRT1/PGC-1α signaling pathway on myocardial ischemia-reperfusion injury in rats.

Wei Zhang, Rongchang Chen, Keyi Xu, Haibiao Guo, Chuyuan Li, Xiaobo Sun.

  BACKGROUND: Xinmai'an tablets are a compound Chinese medicine comprising six traditional Chinese medicines that have been clinically applied to treat cardiovascular diseases such as premature ventricular contractions for many years. However, pharmacological effects and underlying mechanisms of Xinmai'an tablet in protecting against myocardial ischemia-reperfusion injury (MIRI) were barely ever studied.PURPOSE: To investigate the cardioprotective properties of Xinmai'an tablet against MIRI and the underlying molecular mechanism in rats.
METHODS: We initially established the UHPLC-QTRAP-MS/MS analysis method to ensure the controllable quality of Xinmai'an tablet. We further identified the cardioprotective effects of Xinmai'an tablet against MIRI using TTC staining, hematoxylin and eosin, echocardiography, the transmission electron microscope analysis, biochemical analysis, and ELISA. We then investigated whether the safeguarding effect of Xinmai'an tablet on MIRI model rats was related to AMPK/SIRT1/PGC-1α pathway via western blotting.
RESULTS: Xinmai'an tablet decreased myocardial infarct size; ameliorated cardiac function; alleviated myocardial and mitochondrial damage; and suppressed oxidative stress injury, vascular endothelial damage, and apoptosis response in MIRI model rats. Mechanistically, our results showed that Xinmai'an tablet can dramatically activate the AMPK/SIRT1/PGC-1αpathway and subsequently diminish mitochondrial oxidative stress damage. This was evidenced by increased ATP, Na+-K+-ATPase, and Ca2+-Mg2+-ATPase levels, upregulation of GLUT4, p-AMPK, SIRT1, and PGC-1α protein levels; and reduced GLUT1 protein level.
CONCLUSION: To the knowledge of the author of this article, this study is the first report of Xinmai'an tablet attenuating MIRI, potentially associated with the activation of the AMPK/SIRT1/PGC-1α pathway and subsequent reduction of mitochondrial oxidative stress damage. These findings reveal a novel pharmacological effect and mechanism of action of Xinmai'an tablet and highlight a promising therapeutic drug for ischemic cardiovascular diseases.

Keywords:  AMPK/SIRT1/PGC-1α; Cardioprotective effect; Myocardial ischemia-reperfusion injury; Xinmai'an tablet

DOI:  https://doi.org/10.1016/j.phymed.2023.155034
J Mol Cell Cardiol. 2023 Aug 19. pii: S0022-2828(23)00138-4. [Epub ahead of print]183 27-41

PPARδ activation improves cardiac mitochondrial homeostasis in desmin deficient mice but does not alleviate systolic dysfunction.

Dimitra Palioura, Kyriakos Mellidis, Konstantina Ioannidou-Kabouri, Eleftheria Galatou, Eleni-Taxiarchia Mouchtouri, Rodopi Stamatiou, Panagiotis Mavrommatis-Parasidis, Emmanuel Panteris, Aimilia Varela, Constantinos Davos, Konstantinos Drosatos, Manolis Mavroidis, Antigone Lazou.

  Peroxisome proliferator-activated receptor (PPAR) δ is a major transcriptional regulator of cardiac energy metabolism with pleiotropic properties, including anti-inflammatory, anti-oxidative and cardioprotective action. In this study, we sought to investigate whether pharmacological activation of PPARδ via intraperitoneal administration of the selective ligand GW0742 could ameliorate heart failure and mitochondrial dysfunction that have been previously reported in a characterized genetic model of heart failure, the desmin null mice (Des-/-). Our studies demonstrate that treatment of Des-/- mice with the PPARδ agonist attenuated cardiac inflammation, fibrosis and cardiac remodeling. In addition, PPARδ activation alleviated oxidative stress in the failing myocardium as evidenced by decreased ROS levels. Importantly, PPARδ activation stimulated mitochondrial biogenesis, prevented mitochondrial and sarcoplasmic reticulum vacuolar degeneration and improved the mitochondrial intracellular distribution. Finally, PPARδ activation alleviated the mitochondrial respiratory dysfunction, prevented energy depletion and alleviated excessive autophagy and mitophagy in Des-/- hearts. Nevertheless, improvement of all these parameters did not suffice to overcome the significant structural deficiencies that desmin deletion incurs in cardiomyocytes and cardiac function did not improve significantly. In conclusion, pharmacological PPARδ activation in Des-/- hearts exerts protective effects during myocardial degeneration and heart failure by preserving the function and quality of the mitochondrial network. These findings implicate PPARδ agonists as a supplemental constituent of heart failure medications.

Keywords:  Heart failure; Mitochondria; Mitochondrial biogenesis and dynamics; Mitochondrial respiration; Myocardial remodeling; Peroxisome proliferator-activated receptor δ

DOI:  https://doi.org/10.1016/j.yjmcc.2023.08.005
Cells. 2023 Aug 16. pii: 2078. [Epub ahead of print]12(16):

Poly(ADP-Ribose) Polymerase-1 Lacking Enzymatic Activity Is Not Compatible with Mouse Development.

Tatiana Kamaletdinova, Wen Zong, Pavel Urbánek, Sijia Wang, Mara Sannai, Paulius Grigaravičius, Wenli Sun, Zahra Fanaei-Kahrani, Aswin Mangerich, Michael O Hottiger, Tangliang Li, Zhao-Qi Wang.

  Poly(ADP-ribose) polymerase-1 (PARP1) binds DNA lesions to catalyse poly(ADP-ribosyl)ation (PARylation) using NAD+ as a substrate. PARP1 plays multiple roles in cellular activities, including DNA repair, transcription, cell death, and chromatin remodelling. However, whether these functions are governed by the enzymatic activity or scaffolding function of PARP1 remains elusive. In this study, we inactivated in mice the enzymatic activity of PARP1 by truncating its C-terminus that is essential for ART catalysis (PARP1ΔC/ΔC, designated as PARP1-ΔC). The mutation caused embryonic lethality between embryonic day E8.5 and E13.5, in stark contrast to PARP1 complete knockout (PARP1-/-) mice, which are viable. Embryonic stem (ES) cell lines can be derived from PARP1ΔC/ΔC blastocysts, and these mutant ES cells can differentiate into all three germ layers, yet, with a high degree of cystic structures, indicating defects in epithelial cells. Intriguingly, PARP1-ΔC protein is expressed at very low levels compared to its full-length counterpart, suggesting a selective advantage for cell survival. Noticeably, PARP2 is particularly elevated and permanently present at the chromatin in PARP1-ΔC cells, indicating an engagement of PARP2 by non-enzymatic PARP1 protein at the chromatin. Surprisingly, the introduction of PARP1-ΔC mutation in adult mice did not impair their viability; yet, these mutant mice are hypersensitive to alkylating agents, similar to PARP1-/- mutant mice. Our study demonstrates that the catalytically inactive mutant of PARP1 causes the developmental block, plausibly involving PARP2 trapping.

Keywords:  ES cell differentiation; PARP1; PARP2; catalytic activity; development; genotoxic stress

DOI:  https://doi.org/10.3390/cells12162078
Pharmaceuticals (Basel). 2023 Aug 10. pii: 1134. [Epub ahead of print]16(8):

Nicotinamide Riboside Improves Stemness of Human Adipose-Derived Stem Cells and Inhibits Terminal Adipocyte Differentiation.

Somaiah Chinnapaka, Hamid Malekzadeh, Zayaan Tirmizi, José A Arellano, Asim Ejaz.

  Adipose tissue plays a crucial role in maintaining metabolic homeostasis by serving as a storage site for excess fat and protecting other organs from the detrimental effects of lipotoxicity. However, the aging process is accompanied by a redistribution of fat, characterized by a decrease in insulin-sensitive subcutaneous adipose depot and an increase in insulin-resistant visceral adipose depot. This age-related alteration in adipose tissue distribution has implications for metabolic health. Adipose-derived stem cells (ASCs) play a vital role in the regeneration of adipose tissue. However, aging negatively impacts the stemness and regenerative potential of ASCs. The accumulation of oxidative stress and mitochondrial dysfunction-associated cellular damage contributes to the decline in stemness observed in aged ASCs. Nicotinamide adenine dinucleotide (NAD+) is a crucial metabolite that is involved in maintaining cellular homeostasis and stemness. The dysregulation of NAD+ levels with age has been associated with metabolic disorders and the loss of stemness. In this study, we aimed to investigate the effects of nicotinamide riboside (NR), a precursor of NAD+, on the stemness of human ASCs in cell culture. Our findings reveal that adipogenesis is accompanied by an increase in mitochondrial activity and the production of reactive oxygen species (ROS). However, treatment with NR leads to a reduction in mitochondrial activity and ROS production in ASCs. Furthermore, NR administration improves the stemness-related genes expression in ASCs and mitigates their propensity for adipocyte differentiation. These results suggest that NR treatment holds promise as a potential strategy to rejuvenate the stemness of aged ASCs. Further investigations, including in vivo evaluations using animal models and human studies, will be necessary to validate these findings and establish the clinical potential of this well-established drug for enhancing the stemness of aged stem cells.

Keywords:  adipose stem cells; adipose tissue; differentiation; nicotinamide riboside; proliferation; reactive oxygen species; stemness

DOI:  https://doi.org/10.3390/ph16081134
Ageing Res Rev. 2023 Aug 23. pii: S1568-1637(23)00197-6. [Epub ahead of print] 102038

Mitochondrial Transfer Between Cell Crosstalk - An Emerging Role in Mitochondrial Quality Control.

Yi Liu, Tinglv Fu, Guorui Li, Boyang Li, Guoqing Luo, Ning Li, Qing Geng.

  Intercellular signaling and component conduction are essential for multicellular organisms' homeostasis, and mitochondrial transcellular transport is a key example of such cellular component exchange. In physiological situations, mitochondrial transfer is linked with biological development, energy coordination, and clearance of harmful components, remarkably playing important roles in maintaining mitochondrial quality. Mitochondria are engaged in many critical biological activities, like oxidative metabolism and biomolecular synthesis, and are exclusively prone to malfunction in pathological processes. Importantly, severe mitochondrial damage will further amplify the defects in the mitochondrial quality control system, which will mobilize more active mitochondrial transfer, replenish exogenous healthy mitochondria, and remove endogenous damaged mitochondria to facilitate disease outcomes. This review explores intercellular mitochondrial transport in cells, its role in cellular mitochondrial quality control, and the linking mechanisms in cellular crosstalk. We also describe advances in therapeutic strategies for diseases that target mitochondrial transfer.

Keywords:  cell crosstalk; intercellular mitochondrial transfer; mitochondrial quality control; therapy

DOI:  https://doi.org/10.1016/j.arr.2023.102038
Clin Transl Med. 2023 08;13(8): e1377

SIRT6 deficiency in endothelial cells exacerbates oxidative stress by enhancing HIF1α accumulation and H3K9 acetylation at the Ero1α promoter.

Zhenyang Guo, Xueting Yu, Shuang Zhao, Xin Zhong, Dong Huang, Runyang Feng, Peng Li, Zheyan Fang, Yiqing Hu, Zhentao Zhang, Mukaddas Abdurahman, Lei Huang, Yun Zhao, Xiangdong Wang, Junbo Ge, Hua Li.

  BACKGROUND: SIRT6, an important NAD+ -dependent protein, protects endothelial cells from inflammatory and oxidative stress injuries. However, the role of SIRT6 in cardiac microvascular endothelial cells (CMECs) under ischemia-reperfusion injury (IRI) remains unclear.METHODS: The HUVECs model of oxygen-glucose deprivation/reperfusion (OGD/R) was established to simulate the endothelial IRI in vitro. Endoplasmic reticulum oxidase 1 alpha (Ero1α) mRNA and protein levels in SIRT6-overexpressing or SIRT6-knockdown cells were measured by qPCR and Western blotting. The levels of H2 O2 and mitochondrial reactive oxygen species (ROS) were detected to evaluate the status of oxidative stress. The effects of SIRT6 deficiency and Ero1α knockdown on cellular endoplasmic reticulum stress (ERS), inflammation, apoptosis and barrier function were detected by a series of molecular biological experiments and functional experiments in vitro. Chromatin immunoprecipitation, Western blotting, qPCR, and site-specific mutation experiments were used to examine the underlying molecular mechanisms. Furthermore, endothelial cell-specific Sirt6 knockout (ecSirt6-/- ) mice were subjected to cardiac ischemia-reperfusion surgery to investigate the effects of SIRT6 in CMECs in vivo.
RESULTS: The expression of Ero1α was significantly upregulated in SIRT6-knockdown endothelial cells, and high Ero1α expression correlated with the accumulation of H2 O2 and mitochondrial ROS. In addition, SIRT6 deficiency increased ERS, inflammation, apoptosis and endothelial permeability, and these effects could be significantly attenuated by Ero1α knockdown. The deacetylase catalytic activity of SIRT6 was important in regulating Ero1α expression and these biological processes. Mechanistically, SIRT6 inhibited the enrichment of HIF1α and p300 at the Ero1α promoter through deacetylating H3K9, thereby antagonizing HIF1α/p300-mediated Ero1α expression. Compared with SIRT6-wild-type (SIRT6-WT) cells, cells expressing the SIRT6-H133Y-mutant and SIRT6-R65A-mutant exhibited increased Ero1α expression. Furthermore, ecSirt6-/- mice subjected to ischemia-reperfusion surgery exhibited increased Ero1α expression and ERS in CMECs and worsened injuries to microvascular barrier function and cardiac function.
CONCLUSIONS: Our results revealed an epigenetic mechanism associated with SIRT6 and Ero1α expression and highlighted the therapeutic potential of targeting the SIRT6-HIF1α/p300-Ero1α axis.

Keywords:  SIRT6; endoplasmic reticulum stress; ischemia-reperfusion injury

DOI:  https://doi.org/10.1002/ctm2.1377
Sci Total Environ. 2023 Aug 23. pii: S0048-9697(23)05103-3. [Epub ahead of print] 166478

NLRP3 inflammasome-mediated pyroptosis involvement in cadmium exposure-induced cognitive deficits via the Sirt3-mtROS axis.

Dongmei Wang, Yiran Wu, Shihao Sun, Pu Zhao, Xiang Zhou, Chen Liang, Yilu Ma, Sanqiang Li, Xiaoying Zhu, Xueqin Hao, Jian Shi, Hua Fan.

  Cadmium (Cd), a toxic heavy metal, exerts deleterious effects on neuronal survival and cognitive function. NOD-like receptor 3 (NLRP3) inflammasome-dependent pyroptosis has been linked to Cd-induced cytotoxicity. The current research intended to elucidate the role of NLRP3 inflammasome-mediated pyroptosis in Cd-evoked neuronal death and cognitive impairments and the underlying mechanisms. Exposure to 1 mg/kg Cd for 8 weeks led to hippocampal-dependent cognitive deficits and neural/synaptic damage in mice. NLRP3 inflammasome-related protein expression (NLRP3, ASC, and caspase1 p20) and neuronal pyroptosis were significantly upregulated in Cd-treated hippocampi and SH-SY5Y cells. Moreover, pretreatment with the NLRP3 inhibitor MCC950 mitigated Cd-elicited NLRP3 inflammasome activation and subsequent neuronal pyroptosis in SH-SY5Y cells. Furthermore, exposure to Cd downregulated Sirt3 expression, suppressed SOD2 activity by hyperacetylation, and enhanced mtROS accumulation in vivo and in vitro. Notably, Cd-induced NLRP3 inflammasome-dependent neuronal pyroptosis was attenuated by a mtROS scavenger or Sirt3 overexpression in SH-SY5Y cells. In addition, Cd failed to further suppress SOD activity and activate NLRP3 inflammasome-dependent neuronal pyroptosis in Sirt3 shRNA-treated SH-SY5Y cells. Collectively, our findings indicate that Cd exposure induces neuronal injury and cognitive deficits by activating NLRP3 inflammasome-dependent neuronal pyroptosis and that activation of the NLRP3 inflammasome is partially mediated by the Sirt3-mtROS axis.

Keywords:  Cadmium; Cognitive deficits; NLRP3 inflammasome; Pyroptosis; Sirt3-mtROS

DOI:  https://doi.org/10.1016/j.scitotenv.2023.166478
iScience. 2023 Aug 18. 26(8): 107375

Increased SIRT3 combined with PARP inhibition rescues motor function of SBMA mice.

David R Garcia Castro, Joseph R Mazuk, Erin M Heine, Daniel Simpson, R Seth Pinches, Caroline Lozzi, Kathryn Hoffman, Phillip Morrin, Dylan Mathis, Maria V Lebedev, Elyse Nissley, Kang Hoo Han, Tyler Farmer, Diane E Merry, Qiang Tong, Maria Pennuto, Heather L Montie.

  Spinal and bulbar muscular atrophy (SBMA) is a neuromuscular disease with substantial mitochondrial and metabolic dysfunctions. SBMA is caused by polyglutamine (polyQ) expansion in the androgen receptor (AR). Activating or increasing the NAD+-dependent deacetylase, SIRT3, reduced oxidative stress and death of cells modeling SBMA. However, increasing diminished SIRT3 in AR100Q mice failed to reduce acetylation of the SIRT3 target/antioxidant, SOD2, and had no effect on increased total acetylated peptides in quadriceps. Yet, overexpressing SIRT3 resulted in a trend of motor recovery, and corrected TCA cycle activity by decreasing acetylation of SIRT3 target proteins. We sought to boost blunted SIRT3 activity by replenishing diminished NAD+ with PARP inhibition. Although NAD+ was not affected, overexpressing SIRT3 with PARP inhibition fully restored hexokinase activity, correcting the glycolytic pathway in AR100Q quadriceps, and rescued motor endurance of SBMA mice. These data demonstrate that targeting metabolic anomalies can restore motor function downstream of polyQ-expanded AR.

Keywords:  Biochemistry; Biological sciences; Cell biology; Molecular biology

DOI:  https://doi.org/10.1016/j.isci.2023.107375