Advantages
- Future applications for treatment of diabetic nephropathy
- Three mouse models for utilization in diabetic research
- Defined mechanism behind glomerular hyperfiltration
Summary
Abnormal regulation of sodium reabsorption in the thick ascending limb and macula densa underpins disorders such as salt-sensitive hypertension and diabetic hyperfiltration. The NKCC2 cotransporter and neuronal nitric oxide synthase-1 in macula densa cells are critical mediators of tubuloglomerular feedback, glomerular filtration rate, and blood pressure responses to salt or glucose loads. However, existing genetic models suffer from incomplete isoform targeting, lack of full splice-variant deletion, and limited cell-type specificity. This ultimately leads to confounding effects on tubular chloride sensing, primary cilia function, and NOS1-derived NO production. These limitations have impeded precise dissection of individual contributions to renal hemodynamics and sodium handling.
Three genetically engineered mouse strains on a C57BL/6J background enable conditional analysis of NOS1 and NKCC2 in renal hyperfiltration. A NOS1Cre line was created by electroporating a linearized Cre knock-in vector spanning all NOS1 splice variants into embryonic stem cells and was confirmed by drug selection, PCR and Southern blot to retain full NOS1 function. An NKCC2flox line was produced by inserting loxP sites around critical NKCC2 exons via a similar targeting strategy, and a NOS1Cre-NKCC2flox line combines these alleles so that Cre expression in macula densa cells drives NKCC2 excision. This abolishes the tubuloglomerular feedback response under acute hyperglycemic conditions.
Desired Partnership
Includes three technologies: 21A009, 21A051, 21A052