Interdependent Regulation of Polycystin Expression Influences Starvation-Induced Autophagy and Cell Death

Decuypere, Jean-Paul; Giel, Dorien Van; Janssens, Peter; Dong, Ke; Somlo, Stefan; Cai, Yiqiang; Mekahli, Djalila; Vennekens, Rudi

doi:10.3390/ijms222413511

Cited by 8 publications

(8 citation statements)

References 52 publications

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“…To assess whether cell lines that recapitulate ADPKD cystic disease ex vivo express ACLY, one of the targets of BA, we tested the expression of this enzyme by immunoblotting PT- and IMCD-derived model cell lines in cells grown in 2D. All four cell lines tested, parental PT-derived Pkd1 +/- (PH2) cells, PT-derived Pkd1 -/- (PN24) cells (Joly et al, 2006) and IMCD-derived WT-IMCD3 and ID1-3E5 Pkd1 -/- cells (Decuypere et al, 2021) express ACLY (total ACLY or tACLY; Figure 3A and C ). In addition, these cell lines also expressed an active form of ACLY phosphorylated at a target site of Akt (also known as Protein Kinase B; PKB) at Ser-455 (pS455 ACLY).…”

Section: Resultsmentioning

confidence: 99%

Beneficial Effects of Bempedoic Acid Treatment in Polycystic Kidney Disease Cells and Mice

Hallows

Saitta

et al. 2022

Preprint

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Background: ADPKD has few therapeutic options. Tolvaptan slows disease but has side effects limiting its tolerability. Bempedoic acid (BA), an ATP citrate-lyase (ACLY) inhibitor FDA-approved for hypercholesterolemia, catalyzes a key step in fatty acid/sterol synthesis important for cell growth and proliferation. BA also activates AMPK in mice. We hypothesized that BA could be a novel ADPKD therapy by inhibiting cyst growth, proliferation, injury, and metabolic dysregulation via ACLY inhibition and AMPK activation. Methods: ACLY gene and protein expression levels were measured in murine Pkd1-null kidney cell lines derived from proximal tubule (PT) and collecting duct (IMCD), grown in 3D Matrigel cultures and treated +/- BA before cyst analysis. Mitochondria were also characterized using MitoSox and MitoTracker staining. Pkd1fl/fl;Pax8-rtTA;Tet-O-Cre C57BL/6J mice were induced with IP doxycycline injection on postnatal days 10 and 11 (P10 and P11) and then treated +/- BA (30 mg/kg/d) +/- tolvaptan (30-100 mg/kg/d) by oral gavage from P12-21. To assess disease severity, %total kidney weight-to-body weight (%TKW/BW) and BUN levels at euthanasia (P22) were measured. Kidney and liver homogenates were immunoblotted for expression of key disease and other cellular signaling biomarkers. Results: ACLY protein expression and activity were upregulated in ADPKD kidney tissues relative to wild-type. BA inhibited cystic growth in both PT and IMCD-derived Pkd1-null kidney cells. BA also inhibited mitochondrial superoxide production and promoted mitochondrial elongation in these cells, suggesting improved mitochondrial function. In ADPKD mice, BA reduced %TKW/BW and BUN to a similar extent as tolvaptan relative to untreated controls. Addition of BA to tolvaptan caused a further reduction in %TKW/BW and BUN vs. tolvaptan alone. BA reduced ACLY and stimulated AMPK activity in kidneys vs. controls. BA also inhibited mTOR and ERK signaling and sharply reduced the injury marker KIM-1 and, to a lesser extent, NGAL. In liver, BA increased mitochondrial biogenesis while inhibiting apoptosis. These BA effects occurred alone and together with tolvaptan. Conclusion: BA inhibited cyst growth in vitro and ADPKD severity in vivo. Combining BA with tolvaptan further improved various ADPKD disease parameters. Repurposing BA may be a promising new ADPKD therapeutic strategy, having beneficial effects when used alone and along with tolvaptan in mice.

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Section: Resultsmentioning

confidence: 99%

Beneficial Effects of Bempedoic Acid Treatment in Polycystic Kidney Disease Cells and Mice

Hallows

Saitta

et al. 2022

Preprint

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“…Mouse inner medullary collecting duct (IMCD) cell lines were also generously provided by Dr. Stefan Somlo. Wild-type (Wt)-IMCD3 (Cas9) is a control cell line for IMCD3-CRISPR-knockout cells (ID1-3E5 Pkd1 −/− ) ( Decuypere et al, 2021 ). Both cell lines were cultured in regular DMEM/F12 medium containing 5% FBS in a 37°C humidified 5% CO 2 -95% air incubator with medium changes every other day and passaged approximately twice weekly.…”

Section: Methodsmentioning

confidence: 99%

Beneficial effects of bempedoic acid treatment in polycystic kidney disease cells and mice

Hallows

Saitta

et al. 2022

Front. Mol. Biosci.

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ADPKD has few therapeutic options. Tolvaptan slows disease but has side effects limiting its tolerability. Bempedoic acid (BA), an ATP citrate-lyase (ACLY) inhibitor FDA-approved for hypercholesterolemia, catalyzes a key step in fatty acid/sterol synthesis important for cell proliferation. BA is activated by very long-chain acyl-CoA synthetase (FATP2) expressed primarily in kidney and liver. BA also activates AMPK. We hypothesized that BA could be a novel ADPKD therapy by inhibiting cyst growth, proliferation, injury, and metabolic dysregulation via ACLY inhibition and AMPK activation. Pkd1-null kidney cell lines derived from mouse proximal tubule (PT) and collecting duct (IMCD) were grown in 2D or 3D Matrigel cultures and treated ± BA, ± SB-204990 (another ACLY inhibitor) or with Acly shRNA before cyst analysis, immunoblotting or mitochondrial assays using MitoSox and MitoTracker staining. Pkd1fl/fl; Pax8-rtTA; Tet-O-Cre C57BL/6J mice were induced with doxycycline injection on postnatal days 10 and 11 (P10-P11) and then treated ± BA (30 mg/kg/d) ± tolvaptan (30–100 mg/kg/d) by gavage from P12-21. Disease severity was determined by % total-kidney-weight-to-bodyweight (%TKW/BW) and BUN levels at euthanasia (P22). Kidney and liver homogenates were immunoblotted for expression of key biomarkers. ACLY expression and activity were upregulated in Pkd1-null PT and IMCD-derived cells vs. controls. Relative to controls, both BA and SB-204990 inhibited cystic growth in Pkd1-null kidney cells, as did Acly knockdown. BA inhibited mitochondrial superoxide production and promoted mitochondrial elongation, suggesting improved mitochondrial function. In ADPKD mice, BA reduced %TKW/BW and BUN to a similar extent as tolvaptan vs. untreated controls. Addition of BA to tolvaptan caused a further reduction in %TKW/BW and BUN vs. tolvaptan alone. BA generally reduced ACLY and stimulated AMPK activity in kidneys and livers vs. controls. BA also inhibited mTOR and ERK signaling and reduced kidney injury markers. In liver, BA treatment, both alone and together with tolvaptan, increased mitochondrial biogenesis while inhibiting apoptosis. We conclude that BA and ACLY inhibition inhibited cyst growth in vitro, and BA decreased ADPKD severity in vivo. Combining BA with tolvaptan further improved various ADPKD disease parameters. Repurposing BA may be a promising new ADPKD therapy, having beneficial effects alone and along with tolvaptan.

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“…In cpk mice and Han:SPRD rats, autophagy is increased as autophagosomes were found by electron microscopy in the tubular cells lining the cysts, and enhanced autophagy components LC3-II and beclin-1 were also observed ( Belibi et al, 2011 ). In PC1 deficient cells, basal autophagy was enhanced ( Decuypere et al, 2021 ). However, in Pkd1 mutant mice, the expression level of autophagy genes was decreased although LC3-II protein level showed no change ( Belibi et al, 2011 ; Chou et al, 2018 ).…”

Section: The Roles and Mechanisms Of Regulated Cell Death In Adpkdmentioning

confidence: 99%

“…In PC1 knockout mice, starvation-induced autophagic response is enhanced. Although knockdown of PC2 in PC1 knockout cells did not significantly alter autophagy level, PC2 knockout cells showed reduced protein level of PC1 and the PC1 band seemed to be at a lower molecular weight, suggesting that the stability of PC1 protein during starvation is dependent on PC2 expression ( Decuypere et al, 2021 ).…”

Section: The Roles and Mechanisms Of Regulated Cell Death In Adpkdmentioning

confidence: 99%

Molecular Mechanisms of Epigenetic Regulation, Inflammation, and Cell Death in ADPKD

Agborbesong

et al. 2022

Front. Mol. Biosci.

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Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disorder, which is caused by mutations in thePKD1andPKD2genes, characterizing by progressive growth of multiple cysts in the kidneys, eventually leading to end-stage kidney disease (ESKD) and requiring renal replacement therapy. In addition, studies indicate that disease progression is as a result of a combination of factors. Understanding the molecular mechanisms, therefore, should facilitate the development of precise therapeutic strategies for ADPKD treatment. The roles of epigenetic modulation, interstitial inflammation, and regulated cell death have recently become the focuses in ADPKD. Different epigenetic regulators, and the presence of inflammatory markers detectable even before cyst growth, have been linked to cyst progression. Moreover, the infiltration of inflammatory cells, such as macrophages and T cells, have been associated with cyst growth and deteriorating renal function in humans and PKD animal models. There is evidence supporting a direct role of the PKD gene mutations to the regulation of epigenetic mechanisms and inflammatory response in ADPKD. In addition, the role of regulated cell death, including apoptosis, autophagy and ferroptosis, have been investigated in ADPKD. However, there is no consensus whether cell death promotes or delays cyst growth in ADPKD. It is therefore necessary to develop an interactive picture between PKD gene mutations, the epigenome, inflammation, and cell death to understand why inherited PKD gene mutations in patients may result in the dysregulation of these processes that increase the progression of renal cyst formation.

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Interdependent Regulation of Polycystin Expression Influences Starvation-Induced Autophagy and Cell Death

Cited by 8 publications

References 52 publications

Beneficial Effects of Bempedoic Acid Treatment in Polycystic Kidney Disease Cells and Mice

Beneficial Effects of Bempedoic Acid Treatment in Polycystic Kidney Disease Cells and Mice

Beneficial effects of bempedoic acid treatment in polycystic kidney disease cells and mice

Molecular Mechanisms of Epigenetic Regulation, Inflammation, and Cell Death in ADPKD

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