Diabetes-induced changes in the alternative splicing of the slo gene in corporal tissue.
OBJECTIVE
Erectile dysfunction is a common diabetic complication. Preclinical studies have documented that the Slo gene (encoding the BK or Maxi-K channel alpha-subunit) plays a critical role in erectile function. Therefore, we determined whether diabetes induces changes in the splicing of the Slo gene relevant to erectile function.


METHODS
Reverse transcriptase-polymerase chain reaction was used to compare Slo splice variant expression in corporal tissue excised from control and streptozotocin (STZ)-induced diabetic Fischer F-344 rats. Splice variants were sequenced, characterized by patch clamping, and fused to green fluorescent protein to determine cellular localization. The impact of altered Slo expression on erectile function was further evaluated in vivo.


RESULTS
A novel Slo splice variant (SVcyt, with a cytoplasmic location) was predominantly expressed in corporal tissue from control rats. STZ-diabetes caused upregulation of a channel-forming transcript SV0. Preliminary results suggest that SV0 was also more prevalent in the corporal tissue of human diabetic compared with nondiabetic patients. The change in isoform expression in STZ-treated rats was partially reversed by insulin treatment. Intracorporal injection of a plasmid expressing the SV0 transcript, but not SVcyt, restored erectile function in STZ-diabetic rats.


CONCLUSIONS
Alternative splicing of the Slo transcript may represent an important compensatory mechanism to increase the ease with which relaxation of corporal tissue may be triggered as a result of a diabetes-related decline in erectile capacity.
Davies
Kelvin P
KP
Department of Urology, Albert Einstein College of Medicine, Bronx, NY 10461, USA. kdavies@aecom.yu.edu
Zhao
Weixin
W
Tar
Moses
M
Figueroa
Johanna C
JC
Desai
Pratik
P
Verselis
Vytas K
VK
Kronengold
Jack
J
Wang
Hong-Zhan
HZ
Melman
Arnold
A
Christ
George J
GJ
D017398:Alternative Splicing; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D048909:Diabetes Complications / Q000235:genetics*; D003921:Diabetes Mellitus, Experimental / Q000235:genetics*; D007172:Erectile Dysfunction / Q000209:etiology / Q000235:genetics; D006801:Humans; D007668:Kidney; D051037:Large-Conductance Calcium-Activated Potassium Channel alpha Subunits / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D051381:Rats; D011916:Rats, Inbred F344; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection
C494841:KCNMA1 protein, human; C494842:Kcnma1 protein, rat; D051037:Large-Conductance Calcium-Activated Potassium Channel alpha Subunits