Human SLC4A11-C functions as a DIDS-stimulatable H⁺(OH⁻) permeation pathway: partial correction of R109H mutant transport.
The SLC4A11 gene mutations cause a variety of genetic corneal diseases, including congenital hereditary endothelial dystrophy 2 (CHED2), Harboyan syndrome, some cases of Fuchs' endothelial dystrophy (FECD), and possibly familial keratoconus. Three NH2-terminal variants of the human SLC4A11 gene, named SLC4A11-A, -B, and -C are known. The SLC4A11-B variant has been the focus of previous studies. Both the expression of the SLC4A11-C variant in the cornea and its functional properties have not been characterized, and therefore its potential pathophysiological role in corneal diseases remains to be explored. In the present study, we demonstrate that SLC4A11-C is the predominant SLC4A11 variant expressed in human corneal endothelial mRNA and that the transporter functions as an electrogenic H(+)(OH(-)) permeation pathway. Disulfonic stilbenes, including 4,4'-diisothiocyano-2,2'-stilbenedisulfonate (DIDS), 4,4'-diisothiocyanatodihydrostilbene-2,2'-disulfonate (H2DIDS), and 4-acetamido-4'-isothiocyanato-stilbene-2,2'-disulfonate (SITS), which are known to bind covalently, increased SLC4A11-C-mediated H(+)(OH(-)) flux by 150-200% without having a significant effect in mock-transfected cells. Noncovalently interacting 4,4'-diaminostilbene-2,2'-disulfonate (DADS) was without effect. We tested the efficacy of DIDS on the functionally impaired R109H mutant (SLC4A11-C numbering) that causes CHED2. DIDS (1 mM) increased H(+)(OH(-)) flux through the mutant transporter by ∼40-90%. These studies provide a basis for future testing of more specific chemically modified dilsulfonic stilbenes as potential therapeutic agents to improve the functional impairment of specific SLC4A11 mutant transporters.
Division of Nephrology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California; and.
Liyo
L
Kao
Division of Nephrology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California; and.
Rustam
R
Azimov
Division of Nephrology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California; and.
Natalia
N
Abuladze
Division of Nephrology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California; and.
Debra
D
Newman
Division of Nephrology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California; and Brain Research Institute, University of California Los Angeles, Los Angeles, California ikurtz@mednet.ucla.edu.
Ira
I
Kurtz
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000031:analogs & derivatives / Q000494:pharmacology*; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D027321:Anion Transport Proteins / Q000235:genetics / Q000378:metabolism*; D017920:Antiporters / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport / Q000502:physiology; D002460:Cell Line; D003315:Cornea / Q000187:drug effects / Q000378:metabolism; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D006878:Hydroxides / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D010539:Permeability / Q000187:drug effects*; D012333:RNA, Messenger / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects*
D027321:Anion Transport Proteins; D017920:Antiporters; D006878:Hydroxides; D012333:RNA, Messenger; C425809:SLC4A11 protein, human; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; C018564:dihydro-DIDS; C025953:amsonic acid; C031356:hydroxide ion; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid
CHED2; DIDS; cornea; endothelial cell; proton; transport