ADCK4 Deficiency Destabilizes the Coenzyme Q Complex, Which Is Rescued by 2,4-Dihydroxybenzoic Acid Treatment

TY - JOUR

T1 - ADCK4 Deficiency Destabilizes the Coenzyme Q Complex, Which Is Rescued by 2,4-Dihydroxybenzoic Acid Treatment

AU - Widmeier, Eugen

AU - Yu, Seyoung

AU - Nag, Anish

AU - Chung, Youn Wook

AU - Nakayama, Makiko

AU - Fernández-Del-Río, Lucía

AU - Hugo, Hannah

AU - Schapiro, David

AU - Buerger, Florian

AU - Choi, Won-Il

AU - Helmstädter, Martin

AU - Kim, Jae-Woo

AU - Ryu, Ji-Hwan

AU - Lee, Min Goo

AU - Clarke, Catherine F

AU - Hildebrandt, Friedhelm

AU - Gee, Heon Yung

N1 - Copyright © 2020 by the American Society of Nephrology.

PY - 2020/6

Y1 - 2020/6

N2 - BACKGROUND: Mutations in ADCK4 (aarF domain containing kinase 4) generally manifest as steroid-resistant nephrotic syndrome and induce coenzyme Q10 (CoQ10) deficiency. However, the molecular mechanisms underlying steroid-resistant nephrotic syndrome resulting from ADCK4 mutations are not well understood, largely because the function of ADCK4 remains unknown.METHODS: To elucidate the ADCK4's function in podocytes, we generated a podocyte-specific, Adck4-knockout mouse model and a human podocyte cell line featuring knockout of ADCK4. These knockout mice and podocytes were then treated with 2,4-dihydroxybenzoic acid (2,4-diHB), a CoQ10 precursor analogue, or with a vehicle only. We also performed proteomic mass spectrometry analysis to further elucidate ADCK4's function.RESULTS: Absence of Adck4 in mouse podocytes caused FSGS and albuminuria, recapitulating features of nephrotic syndrome caused by ADCK4 mutations. In vitro studies revealed that ADCK4-knockout podocytes had significantly reduced CoQ10 concentration, respiratory chain activity, and mitochondrial potential, and subsequently displayed an increase in the number of dysmorphic mitochondria. However, treatment of 3-month-old knockout mice or ADCK4-knockout cells with 2,4-diHB prevented the development of renal dysfunction and reversed mitochondrial dysfunction in podocytes. Moreover, ADCK4 interacted with mitochondrial proteins such as COQ5, as well as cytoplasmic proteins such as myosin and heat shock proteins. Thus, ADCK4 knockout decreased the COQ complex level, but overexpression of ADCK4 in ADCK4-knockout podocytes transfected with wild-type ADCK4 rescued the COQ5 level.CONCLUSIONS: Our study shows that ADCK4 is required for CoQ10 biosynthesis and mitochondrial function in podocytes, and suggests that ADCK4 in podocytes stabilizes proteins in complex Q in podocytes. Our study also suggests a potential treatment strategy for nephrotic syndrome resulting from ADCK4 mutations.

AB - BACKGROUND: Mutations in ADCK4 (aarF domain containing kinase 4) generally manifest as steroid-resistant nephrotic syndrome and induce coenzyme Q10 (CoQ10) deficiency. However, the molecular mechanisms underlying steroid-resistant nephrotic syndrome resulting from ADCK4 mutations are not well understood, largely because the function of ADCK4 remains unknown.METHODS: To elucidate the ADCK4's function in podocytes, we generated a podocyte-specific, Adck4-knockout mouse model and a human podocyte cell line featuring knockout of ADCK4. These knockout mice and podocytes were then treated with 2,4-dihydroxybenzoic acid (2,4-diHB), a CoQ10 precursor analogue, or with a vehicle only. We also performed proteomic mass spectrometry analysis to further elucidate ADCK4's function.RESULTS: Absence of Adck4 in mouse podocytes caused FSGS and albuminuria, recapitulating features of nephrotic syndrome caused by ADCK4 mutations. In vitro studies revealed that ADCK4-knockout podocytes had significantly reduced CoQ10 concentration, respiratory chain activity, and mitochondrial potential, and subsequently displayed an increase in the number of dysmorphic mitochondria. However, treatment of 3-month-old knockout mice or ADCK4-knockout cells with 2,4-diHB prevented the development of renal dysfunction and reversed mitochondrial dysfunction in podocytes. Moreover, ADCK4 interacted with mitochondrial proteins such as COQ5, as well as cytoplasmic proteins such as myosin and heat shock proteins. Thus, ADCK4 knockout decreased the COQ complex level, but overexpression of ADCK4 in ADCK4-knockout podocytes transfected with wild-type ADCK4 rescued the COQ5 level.CONCLUSIONS: Our study shows that ADCK4 is required for CoQ10 biosynthesis and mitochondrial function in podocytes, and suggests that ADCK4 in podocytes stabilizes proteins in complex Q in podocytes. Our study also suggests a potential treatment strategy for nephrotic syndrome resulting from ADCK4 mutations.

KW - Animals

KW - Enzyme Stability

KW - Glomerulosclerosis, Focal Segmental/etiology

KW - HEK293 Cells

KW - Humans

KW - Hydroxybenzoates/pharmacology

KW - Methyltransferases/metabolism

KW - Mice

KW - Mice, Inbred C57BL

KW - Mitochondria/physiology

KW - Mitochondrial Proteins/metabolism

KW - Podocytes/enzymology

KW - Protein Kinases/physiology

KW - Ubiquinone/analogs & derivatives

U2 - 10.1681/ASN.2019070756

DO - 10.1681/ASN.2019070756

M3 - SCORING: Journal article

C2 - 32381600

VL - 31

SP - 1191

EP - 1211

JO - J AM SOC NEPHROL

JF - J AM SOC NEPHROL

SN - 1046-6673

IS - 6

ER -