APOL1Renal-Risk Variants Induce Mitochondrial Dysfunction.
APOL1G1 and G2 variants facilitate kidney disease in blacks. To elucidate the pathways whereby these variants contribute to disease pathogenesis, we established HEK293 cell lines stably expressing doxycycline-inducible (Tet-on) referenceAPOL1G0 or the G1 and G2 renal-risk variants, and used Illumina human HT-12 v4 arrays and Affymetrix HTA 2.0 arrays to generate global gene expression data with doxycycline induction. Significantly altered pathways identified through bioinformatics analyses involved mitochondrial function; results from immunoblotting, immunofluorescence, and functional assays validated these findings. Overexpression ofAPOL1by doxycycline induction in HEK293 Tet-on G1 and G2 cells led to impaired mitochondrial function, with markedly reduced maximum respiration rate, reserve respiration capacity, and mitochondrial membrane potential. Impaired mitochondrial function occurred before intracellular potassium depletion or reduced cell viability occurred. Analysis of global gene expression profiles in nondiseased primary proximal tubule cells from black patients revealed that the nicotinate phosphoribosyltransferase gene, responsible for NAD biosynthesis, was among the top downregulated transcripts in cells with twoAPOL1renal-risk variants compared with those without renal-risk variants; nicotinate phosphoribosyltransferase also displayed gene expression patterns linked to mitochondrial dysfunction in HEK293 Tet-onAPOL1cell pathway analyses. These results suggest a pivotal role for mitochondrial dysfunction inAPOL1-associated kidney disease.
Department of Internal Medicine, Section on Nephrology, lima@wakehealth.edu bfreedma@wakehealth.edu.|Center for Public Health Genomics.
Lijun
L
Ma
Center for Public Health Genomics.|Division of Public Health Sciences, Department of Biostatistical Sciences.
Jeff W
JW
Chou
Department of Internal Medicine, Section on Nephrology.
James A
JA
Snipes
Department of Internal Medicine, Section on Gerontology and Geriatric Medicine.
Manish S
MS
Bharadwaj
Department of Cancer Biology.
Ann L
AL
Craddock
Department of Internal Medicine, Section on Molecular Medicine.
Dongmei
D
Cheng
Department of Internal Medicine, Section on Molecular Medicine.
Allison
A
Weckerle
Department of Physiology and Pharmacology.
Snezana
S
Petrovic
Department of Biochemistry.
Pamela J
PJ
Hicks
Department of Urology, and.
Ashok K
AK
Hemal
Center for Public Health Genomics.|Department of Cancer Biology.
Gregory A
GA
Hawkins
Department of Cancer Biology.
Lance D
LD
Miller
Department of Internal Medicine, Section on Gerontology and Geriatric Medicine.
Anthony J A
AJ
Molina
Center for Public Health Genomics.|Division of Public Health Sciences, Department of Biostatistical Sciences.
Carl D
CD
Langefeld
Department of Internal Medicine, Section on Nephrology.
Mariana
M
Murea
Department of Internal Medicine, Section on Molecular Medicine.
John S
JS
Parks
Department of Internal Medicine, Section on Nephrology, lima@wakehealth.edu bfreedma@wakehealth.edu.|Center for Public Health Genomics.|Center for Diabetes Research, Wake Forest School of Medicine, Winston-Salem, North Carolina.
Barry I
BI
Freedman
D000075944:Apolipoprotein L1; D001053:Apolipoproteins / Q000235:genetics*; D044383:Black People; D002478:Cells, Cultured; D005260:Female; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D006801:Humans; D007674:Kidney Diseases / Q000235:genetics*; D008075:Lipoproteins, HDL / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D028361:Mitochondrial Diseases / Q000235:genetics*; D012307:Risk Factors
C108666:APOL1 protein, human; D000075944:Apolipoprotein L1; D001053:Apolipoproteins; D008075:Lipoproteins, HDL
APOL1; chronic kidney disease; mitochondria