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Specific deletion of glycogen synthase kinase-3β in the renal proximal tubule protects against acute nephrotoxic injury in mice.

Howard C, Tao S, Yang HC, Fogo AB, Woodgett JR, Harris RC, Rao R - Kidney Int. (2012)

Bottom Line: This confirmed that hastened repair in the knockout mice was not merely due to lower initial injury levels.Thus, inhibition of GSK3β prior to nephrotoxic insult protects from renal injury.Such treatment after acute kidney injury may accelerate repair and regeneration.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA.

ABSTRACT
Renal proximal tubular damage and repair are hallmarks of acute kidney injury. As glycogen synthase kinase-3β (GSK3β) is an important cellular regulator of survival and proliferation, we determined its role during injury and recovery of proximal tubules in a mercuric chloride-induced nephrotoxic model of acute kidney injury. Renal proximal tubule-specific GSK3β knockout mice exposed to mercuric chloride had improved survival and renal function compared to wild-type mice. Apoptosis, measured by TUNEL staining, Bax activation, and caspase 3 cleavage, was reduced in the knockout mice. The restoration of renal structure, function, and cell proliferation was also accelerated in the GSK3β knockout mice. This enhanced repair, evidenced by increased Ki-67 and BRDU staining, along with increased cyclin D1 and c-myc levels, was recapitulated by treatment of wild-type mice with the small-molecule GSK3 inhibitor TDZD-8 following injury. This confirmed that hastened repair in the knockout mice was not merely due to lower initial injury levels. Thus, inhibition of GSK3β prior to nephrotoxic insult protects from renal injury. Such treatment after acute kidney injury may accelerate repair and regeneration.

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Related in: MedlinePlus

Reduced expression of GSK3β in renal proximal tubules of KO miceWestern blot analysis shows reduced GSK3β protein levels in tissue lysate of GSK3βloxp/loxp, γ-GT-Cre+/+ (KO) compared to GSK3βloxp/loxp, γ-GT-Cre−/− (WT) in a) whole renal cortex and b) acutely isolated proximal tubules from renal cortex. c) Immunohistochemical staining shows expression of GSK3β reduced in proximal tubules (PT) but not in the collecting ducts (CD) of KO mice (anti GSK3β antibody, x200 original magnification).
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Figure 1: Reduced expression of GSK3β in renal proximal tubules of KO miceWestern blot analysis shows reduced GSK3β protein levels in tissue lysate of GSK3βloxp/loxp, γ-GT-Cre+/+ (KO) compared to GSK3βloxp/loxp, γ-GT-Cre−/− (WT) in a) whole renal cortex and b) acutely isolated proximal tubules from renal cortex. c) Immunohistochemical staining shows expression of GSK3β reduced in proximal tubules (PT) but not in the collecting ducts (CD) of KO mice (anti GSK3β antibody, x200 original magnification).

Mentions: To obtain renal proximal tubule specific gene deletion of GSK3β, we bred GSK3βloxp/loxp mice35 with γ-GT-Cre+/+ mice36. Mice progeny exhibited the expected Mendelian ratio and histo-pathological examination revealed no renal abnormalities in the knockout (KO) mice (GSK3βloxp/loxp, γ-GT-Cre+/+) when compared to wild type (WT) (GSK3βloxp/loxp, γ-GT-Cre−/−). Western blot analysis of lysate from whole renal cortex (Fig 1a) and isolated proximal tubules (Fig 1b) showed significantly reduced levels of GSK3β expression in the KO mice compared to WT mice. Immunohistochemical staining with antibodies selective for GSK3β showed significantly reduced levels of GSK3β in the proximal tubules but not in other nephron segments of KO mice (Fig 1c).


Specific deletion of glycogen synthase kinase-3β in the renal proximal tubule protects against acute nephrotoxic injury in mice.

Howard C, Tao S, Yang HC, Fogo AB, Woodgett JR, Harris RC, Rao R - Kidney Int. (2012)

Reduced expression of GSK3β in renal proximal tubules of KO miceWestern blot analysis shows reduced GSK3β protein levels in tissue lysate of GSK3βloxp/loxp, γ-GT-Cre+/+ (KO) compared to GSK3βloxp/loxp, γ-GT-Cre−/− (WT) in a) whole renal cortex and b) acutely isolated proximal tubules from renal cortex. c) Immunohistochemical staining shows expression of GSK3β reduced in proximal tubules (PT) but not in the collecting ducts (CD) of KO mice (anti GSK3β antibody, x200 original magnification).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472082&req=5

Figure 1: Reduced expression of GSK3β in renal proximal tubules of KO miceWestern blot analysis shows reduced GSK3β protein levels in tissue lysate of GSK3βloxp/loxp, γ-GT-Cre+/+ (KO) compared to GSK3βloxp/loxp, γ-GT-Cre−/− (WT) in a) whole renal cortex and b) acutely isolated proximal tubules from renal cortex. c) Immunohistochemical staining shows expression of GSK3β reduced in proximal tubules (PT) but not in the collecting ducts (CD) of KO mice (anti GSK3β antibody, x200 original magnification).
Mentions: To obtain renal proximal tubule specific gene deletion of GSK3β, we bred GSK3βloxp/loxp mice35 with γ-GT-Cre+/+ mice36. Mice progeny exhibited the expected Mendelian ratio and histo-pathological examination revealed no renal abnormalities in the knockout (KO) mice (GSK3βloxp/loxp, γ-GT-Cre+/+) when compared to wild type (WT) (GSK3βloxp/loxp, γ-GT-Cre−/−). Western blot analysis of lysate from whole renal cortex (Fig 1a) and isolated proximal tubules (Fig 1b) showed significantly reduced levels of GSK3β expression in the KO mice compared to WT mice. Immunohistochemical staining with antibodies selective for GSK3β showed significantly reduced levels of GSK3β in the proximal tubules but not in other nephron segments of KO mice (Fig 1c).

Bottom Line: This confirmed that hastened repair in the knockout mice was not merely due to lower initial injury levels.Thus, inhibition of GSK3β prior to nephrotoxic insult protects from renal injury.Such treatment after acute kidney injury may accelerate repair and regeneration.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA.

ABSTRACT
Renal proximal tubular damage and repair are hallmarks of acute kidney injury. As glycogen synthase kinase-3β (GSK3β) is an important cellular regulator of survival and proliferation, we determined its role during injury and recovery of proximal tubules in a mercuric chloride-induced nephrotoxic model of acute kidney injury. Renal proximal tubule-specific GSK3β knockout mice exposed to mercuric chloride had improved survival and renal function compared to wild-type mice. Apoptosis, measured by TUNEL staining, Bax activation, and caspase 3 cleavage, was reduced in the knockout mice. The restoration of renal structure, function, and cell proliferation was also accelerated in the GSK3β knockout mice. This enhanced repair, evidenced by increased Ki-67 and BRDU staining, along with increased cyclin D1 and c-myc levels, was recapitulated by treatment of wild-type mice with the small-molecule GSK3 inhibitor TDZD-8 following injury. This confirmed that hastened repair in the knockout mice was not merely due to lower initial injury levels. Thus, inhibition of GSK3β prior to nephrotoxic insult protects from renal injury. Such treatment after acute kidney injury may accelerate repair and regeneration.

Show MeSH
Related in: MedlinePlus