Sirtuin 3 regulates mitochondrial protein acetylation and metabolism in tubular epithelial cells during renal fibrosis

AbstractProximal tubular epithelial cells (TECs) demand high energy and rely on mitochondrial oxidative phosphorylation as the main energy source. However, this is disturbed in renal fibrosis. Acetylation is an important post-translational modification for mitochondrial metabolism. The mitochondrial protein NAD+-dependent deacetylase sirtuin 3 (SIRT3) regulates mitochondrial metabolic function. Therefore, we aimed to identify the changes in the acetylome in tubules from fibrotic kidneys and determine their association with mitochondria. We found that decreased SIRT3 expression was accompanied by increased acetylation in mitochondria that have separated from TECs during the early phase of renal fibrosis. Sirt3 knockout mice were susceptible to hyper-acetylated mitochondrial proteins and to severe renal fibrosis. The activation of SIRT3 by honokiol ameliorated acetylation and prevented renal fibrosis. Analysis of the acetylome in separated tubules using LC–MS/MS showed that most kidney proteins were hyper-acetylated after unilateral ureteral obstruction. The increased acetylated proteins with 26.76% were mitochondrial proteins which were mapped to a broad range of mitochondrial pathways including fatty acid β-oxidation, the tricarboxylic acid cycle (TCA cycle), and oxidative phosphorylation. Pyruvate dehydrogenase E1α (PDHE1α), which is the primary link between glycolysis and the TCA cycle, was hyper-acetylated at lysine 385 in TECs after TGF-β1 stimulation and was regulated by SIRT3. Our findings showed that mitochondrial proteins involved in regulating energy metabolism were acetylated and targeted by SIRT3 in TECs. The deacetylation of PDHE1α by SIRT3 at lysine 385 plays a key role in metabolic reprogramming associated with renal fibrosis.

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Sodium-Glucose Co-Transporter 2 Inhibitors Correct Metabolic Maladaptation of Proximal Tubular Epithelial Cells in High-Glucose Conditions

International Journal of Molecular Sciences ◽

10.3390/ijms21207676 ◽

2020 ◽

Vol 21 (20) ◽

pp. 7676

Author(s):

Kohsuke Shirakawa ◽

Motoaki Sano

Keyword(s):

Epithelial Cells ◽

High Glucose ◽

Renal Fibrosis ◽

Sglt2 Inhibitors ◽

Metabolic Reprogramming ◽

Phase Iii ◽

Tubular Epithelial Cells ◽

Proximal Tubular Epithelial Cells ◽

Proximal Tubular ◽

Ros Formation

Glucose filtered in the glomerulus is actively reabsorbed by sodium-glucose co-transporter 2 (SGLT2) in proximal tubular epithelial cells (PTEC) and passively returned to the blood via glucose transporter 2 (GLUT2). Healthy PTEC rely primarily on fatty acid beta-oxidation (FAO) for energy. In phase III trials, SGLT2 inhibitors improved outcomes in diabetic kidney disease (DKD). Tubulointerstitial renal fibrosis due to altered metabolic reprogramming of PTEC might be at the root of the pathogenesis of DKD. Here, we investigated the molecular mechanism of SGLT2 inhibitors’ renoprotective effect by examining transcriptional activity of Spp1, which encodes osteopontin, a key mediator of tubulointerstitial renal fibrosis. With primary cultured PTEC from Spp1-enhanced green fluorescent protein knock-in mice, we proved that in high-glucose conditions, increased SGLT2- and GLUT-mediated glucose uptake is causatively involved in aberrant activation of the glycolytic pathway in PTEC, thereby increasing mitochondrial reactive oxygen species (ROS) formation and transcriptional activation of Spp1. FAO activation did not play a direct role in these processes, but elevated expression of a tubular-specific enzyme, myo-inositol oxygenase, was at least partly involved. Notably, canagliflozin blocked overexpression of myo-inositol oxygenase. In conclusion, SGLT2 inhibitors exerted renoprotective effects by inhibiting aberrant glycolytic metabolism and mitochondrial ROS formation in PTEC in high-glucose conditions.

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Numb Induces E-Cadherin Adhesion Dissolution, Cytoskeleton Reorganization, and Migration in Tubular Epithelial Cells Contributing to Renal Fibrosis

Current Molecular Medicine ◽

10.2174/1566524015666150505162015 ◽

2015 ◽

Vol 15 (4) ◽

pp. 368-379 ◽

Cited By ~ 10

Author(s):

X. Ding ◽

M. Ma ◽

J. Teng ◽

F. Shao ◽

R.K.F. Teng ◽

...

Keyword(s):

Epithelial Cells ◽

Renal Fibrosis ◽

Tubular Epithelial Cells ◽

Cytoskeleton Reorganization ◽

And Migration ◽

E Cadherin

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CORRIGENDUM: WNT1‐inducible signaling protein‐1 mediates TGF‐β1‐induced renal fibrosis in tubular epithelial cells and unilateral ureteral obstruction mouse models via autophagy

Journal of Cellular Physiology ◽

10.1002/jcp.30469 ◽

2021 ◽

Keyword(s):

Epithelial Cells ◽

Mouse Models ◽

Ureteral Obstruction ◽

Renal Fibrosis ◽

Unilateral Ureteral Obstruction ◽

Tubular Epithelial Cells ◽

Signaling Protein ◽

Tgf Β1

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The ATP Synthase Deficiency in Human Diseases

Life ◽

10.3390/life11040325 ◽

2021 ◽

Vol 11 (4) ◽

pp. 325

Author(s):

Chiara Galber ◽

Stefania Carissimi ◽

Alessandra Baracca ◽

Valentina Giorgio

Keyword(s):

Oxidative Phosphorylation ◽

Atp Synthase ◽

Mitochondrial Protein ◽

High Energy ◽

Neurocognitive Disorders ◽

Human Diseases ◽

Age Related ◽

Muscle Tissues ◽

Mitochondrial Atp Synthase ◽

Genes Encoding

Human diseases range from gene-associated to gene-non-associated disorders, including age-related diseases, neurodegenerative, neuromuscular, cardiovascular, diabetic diseases, neurocognitive disorders and cancer. Mitochondria participate to the cascades of pathogenic events leading to the onset and progression of these diseases independently of their association to mutations of genes encoding mitochondrial protein. Under physiological conditions, the mitochondrial ATP synthase provides the most energy of the cell via the oxidative phosphorylation. Alterations of oxidative phosphorylation mainly affect the tissues characterized by a high-energy metabolism, such as nervous, cardiac and skeletal muscle tissues. In this review, we focus on human diseases caused by altered expressions of ATP synthase genes of both mitochondrial and nuclear origin. Moreover, we describe the contribution of ATP synthase to the pathophysiological mechanisms of other human diseases such as cardiovascular, neurodegenerative diseases or neurocognitive disorders.

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Identification of a microRNA signature in renal fibrosis: role of miR-21

AJP Renal Physiology ◽

10.1152/ajprenal.00273.2011 ◽

2011 ◽

Vol 301 (4) ◽

pp. F793-F801 ◽

Cited By ~ 169

Author(s):

Abolfazl Zarjou ◽

Shanzhong Yang ◽

Edward Abraham ◽

Anupam Agarwal ◽

Gang Liu

Keyword(s):

Epithelial Cells ◽

Renal Fibrosis ◽

Transforming Growth Factor ◽

Response To Treatment ◽

Tubular Epithelial Cells ◽

Altered Expression ◽

Tnf Α ◽

Tgf Β1

Renal fibrosis is a final stage of many forms of kidney disease and leads to impairment of kidney function. The molecular pathogenesis of renal fibrosis is currently not well-understood. microRNAs (miRNAs) are important players in initiation and progression of many pathologic processes including diabetes, cancer, and cardiovascular disease. However, the role of miRNAs in kidney injury and repair is not well-characterized. In the present study, we found a unique miRNA signature associated with unilateral ureteral obstruction (UUO)-induced renal fibrosis. We found altered expression in UUO kidneys of miRNAs that have been shown to be responsive to stimulation by transforming growth factor (TGF)-β1 or TNF-α. Among these miRNAs, miR-21 demonstrated the greatest increase in UUO kidneys. The enhanced expression of miR-21 was located mainly in distal tubular epithelial cells. miR-21 expression was upregulated in response to treatment with TGF-β1 or TNF-α in human renal tubular epithelial cells in vitro. Furthermore, we found that blocking miR-21 in vivo attenuated UUO-induced renal fibrosis, presumably through diminishing the expression of profibrotic proteins and reducing infiltration of inflammatory macrophages in UUO kidneys. Our data suggest that targeting specific miRNAs could be a novel therapeutic approach to treat renal fibrosis.

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Loss of the mitochondrial phosphate carrier SLC25A3 induces remodeling of the cardiac mitochondrial protein acylome

AJP Cell Physiology ◽

10.1152/ajpcell.00156.2021 ◽

2021 ◽

Author(s):

Jessica N. Peoples ◽

Nasab Ghazal ◽

Duc M. Duong ◽

Katherine R. Hardin ◽

Janet R. Manning ◽

...

Keyword(s):

Energy Production ◽

Mitochondrial Protein ◽

Atp Synthesis ◽

High Energy ◽

Mitochondrial Proteins ◽

Isocitrate Dehydrogenase 2 ◽

Signaling Organelles ◽

Specific Pathway ◽

Phosphate Carrier

Mitochondria are recognized as signaling organelles because, under stress, mitochondria can trigger various signaling pathways to coordinate the cell's response. The specific pathway(s) engaged by mitochondria in response to mitochondrial energy defects in vivo and in high-energy tissues like the heart are not fully understood. Here, we investigated cardiac pathways activated in response to mitochondrial energy dysfunction by studying mice with cardiomyocyte-specific loss of the mitochondrial phosphate carrier (SLC25A3), an established model that develops cardiomyopathy as a result of defective mitochondrial ATP synthesis. Mitochondrial energy dysfunction induced a striking pattern of acylome remodeling, with significantly increased post-translational acetylation and malonylation. Mass spectrometry-based proteomics further revealed that energy dysfunction-induced remodeling of the acetylome and malonylome preferentially impacts mitochondrial proteins. Acetylation and malonylation modified a highly interconnected interactome of mitochondrial proteins, and both modifications were present on the enzyme isocitrate dehydrogenase 2 (IDH2). Intriguingly, IDH2 activity was enhanced in SLC25A3-deleted mitochondria, and further study of IDH2 sites targeted by both acetylation and malonylation revealed that these modifications can have site-specific and distinct functional effects. Finally, we uncovered a novel crosstalk between the two modifications, whereby mitochondrial energy dysfunction-induced acetylation of sirtuin 5 (SIRT5), inhibited its function. Because SIRT5 is a mitochondrial deacylase with demalonylase activity, this finding suggests that acetylation can modulate the malonylome. Together, our results position acylations as an arm of the mitochondrial response to energy dysfunction and suggest a mechanism by which focal disruption to the energy production machinery can have an expanded impact on global mitochondrial function.

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Role of Stat3 Signaling in Control of EMT of Tubular Epithelial Cells During Renal Fibrosis

Cellular Physiology and Biochemistry ◽

10.1159/000480216 ◽

2017 ◽

Vol 42 (6) ◽

pp. 2552-2558 ◽

Cited By ~ 15

Author(s):

Jingsong Liu ◽

Ying Zhong ◽

Guoyong Liu ◽

Xiaobai Zhang ◽

Bofei Xiao ◽

...

Keyword(s):

Epithelial Cells ◽

Renal Injury ◽

Renal Fibrosis ◽

Critical Role ◽

Dependent Manner ◽

Tubular Epithelial Cells ◽

Mesenchymal Transition ◽

Stat3 Signaling ◽

Phosphorylated Stat3

Background/Aims: Transforming growth factor β 1 (TGFβ1) plays a critical role in the epithelial-to-mesenchymal transition (EMT) of renal tubular epithelial cells (TECs) during renal injury, a major cause of acute renal failure, renal fibrosis and obstructive nephropathy. However, the underlying molecular mechanisms remain ill-defined. Here, we addressed this question. Methods: Expression of TGFβ1, Snail, and phosphorylated Stat3 was examined by immunohistochemistry in the kidney after induction of unilateral ureteral obstruction (UUO) in mice. In vitro, primary TECs were purified by flow cytometry, and then challenged with TGFβ1 with/without presence of specific inhibitors for phosphorylation of SMAD3 or Stat3. Protein levels were determined by Western blotting. Results: We detected significant increases in Snail and phosphorylated Stat3, an activated form for Stat3, in the kidney after induction of UUO in mice. In vitro, TGFβ1-challenged primary TECs upregulated Snail, in a SMAD3/Stat3 dependent manner. Conclusion: Our study sheds light on the mechanism underlying the EMT of TECs after renal injury, and suggests Stat3 signaling as a promising innovative therapeutic target for prevention of renal fibrosis.

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