Related Experiment Videos
In vitro modulation of tubular cyst regression in murine polycystic kidney disease
E D Avner1, W E Sweeney, D Ellis
1Department of Pediatrics, Children's Hospital of Pittsburgh, Pennsylvania.
Abstract:
Recent studies in a murine model of genetically-determined polycystic kidney disease, the CPK mouse, have suggested that alterations in renal Na-K ATPase activity in concert with tubular epithelial hyperplasia have pathogenic import in proximal tubular cyst formation. In the current study, we therefore studied the relative roles of Na-K ATPase activity, tubular epithelial hyperplasia, and basal lamina alterations during in vitro modulation of proximal tubular cyst regression during serum-free organ culture of newborn CPK kidneys. Under basal in vitro conditions, regression of CPK proximal tubular cysts was demonstrated in association with progressive decreases in Na-K ATPase activity and tubular epithelial hyperplasia. The pattern of proximal tubular cyst regression was modified by: a) Na-K ATPase activity induction with triiodothyronine, which promoted proximal tubular cystogenesis; and b) Na-K ATPase activity inhibition with ouabain, which blocked the effects of T3 on the process of cyst formation. Modulation of proximal tubular cystogenesis by Na-K ATPase induction and inhibition were accomplished without significant changes in proximal tubular epithelial hyperplasia or expression of basal lamina components. We conclude that increased Na pump activity may have a significant role in proximal tubular cyst formation and progressive enlargement in the CPK mouse.
Insights
In polycystic kidney disease, increased sodium-potassium pump activity drives cyst formation and growth. Inhibiting this pump may offer a therapeutic target for managing cyst progression.
Area of Science:
- Nephrology
- Molecular Biology
- Genetics
Background:
- Polycystic kidney disease (PKD) is a genetic disorder characterized by cyst formation in the kidneys.
- Previous research in the CPK mouse model suggests a link between renal Na-K ATPase activity, tubular epithelial hyperplasia, and proximal tubular cyst development.
Purpose of the Study:
- To investigate the roles of Na-K ATPase activity, tubular epithelial hyperplasia, and basal lamina alterations in proximal tubular cyst regression.
- To modulate proximal tubular cystogenesis in vitro using serum-free organ culture of newborn CPK kidneys.
Main Methods:
- Utilized organ culture of newborn CPK mouse kidneys under serum-free conditions.
- Assessed Na-K ATPase activity, tubular epithelial hyperplasia, and basal lamina components.
- Modulated Na-K ATPase activity using triiodothyronine (T3) for induction and ouabain for inhibition.
Main Results:
- Under basal conditions, CPK proximal tubular cyst regression correlated with decreased Na-K ATPase activity and tubular epithelial hyperplasia.
- Triiodothyronine-induced Na-K ATPase activity promoted proximal tubular cystogenesis.
- Ouabain inhibition of Na-K ATPase blocked T3's pro-cystogenic effects without altering hyperplasia or basal lamina components.
Conclusions:
- Increased Na-K ATPase activity plays a significant role in the formation and enlargement of proximal tubular cysts in the CPK mouse model.
- Na-K ATPase activity modulation, independent of hyperplasia or basal lamina changes, impacts cystogenesis, suggesting it as a potential therapeutic target.