Podocyte specific deletion of PKM2 ameliorates LPS-induced podocyte injury through beta-catenin

Abstract

Background Acute kidney injury (AKI) is associated with a severe decline in kidney function caused by abnormalities within the podocytes' glomerular matrix. Recently, AKI has been linked to alterations in glycolysis and the activity of glycolytic enzymes, including pyruvate kinase M2 (PKM2). However, the contribution of this enzyme to AKI remains largely unexplored. Methods Cre-loxP technology was used to examine the effects of PKM2 specific deletion in podocytes on the activation status of key signaling pathways involved in the pathophysiology of AKI by lipopolysaccharides (LPS). In addition, we used lentiviral shRNA to generate murine podocytes deficient in PKM2 and investigated the molecular mechanisms mediating PKM2 actions in vitro. Results Specific PKM2 deletion in podocytes ameliorated LPS-induced protein excretion and alleviated LPS-induced alterations in blood urea nitrogen and serum albumin levels. In addition, PKM2 deletion in podocytes alleviated LPS-induced structural and morphological alterations to the tubules and to the brush borders. At the molecular level, PKM2 deficiency in podocytes suppressed LPS-induced inflammation and apoptosis. In vitro, PKM2 knockdown in murine podocytes diminished LPS-induced apoptosis. These effects were concomitant with a reduction in LPS-induced activation of β-catenin and the loss of Wilms’ Tumor 1 (WT1) and nephrin. Notably, the overexpression of a constitutively active mutant of β-catenin abolished the protective effect of PKM2 knockdown. Conversely, PKM2 knockdown cells reconstituted with the phosphotyrosine binding–deficient PKM2 mutant (K433E) recapitulated the effect of PKM2 depletion on LPS-induced apoptosis, β-catenin activation, and reduction in WT1 expression. Conclusions Taken together, our data demonstrates that PKM2 plays a key role in podocyte injury and suggests that targetting PKM2 in podocytes could serve as a promising therapeutic strategy for AKI. Trial registration Not applicable.

Proficient Novel Biomarkers Guide Early Detection of Acute Kidney Injury: A Review

“…Animals having podocyte-specific removal of PKM2 showed increased albuminuria and glomerular damage brought on by hyperglycemia. Although attempts have been made to describe PKM2’s activity in the kidneys, especially in the context of hyperglycemia-induced glomerular damage, more research has to be done on how it could play a role in the etiology of AKI [ 30 ].…”

Pyruvate kinase M2 regulates mitochondrial homeostasis in cisplatin-induced acute kidney injury

“…TEPP46 also showed the pro-survival ability during LPS or D-galactosamine (D-Gal) induced liver injury [ 45 ]. Furthermore, podocyte specific deletion of PKM2 ameliorated LPS-induced podocyte injury [ 46 ]. In this study, we found that the specific loss of PKM2 or inhibition of PKM2 phosphorylation or dimerization could promote the survival of renal tubular epithelial cells in cisplatin-induced AKI.…”

Shikonin Alleviates Gentamicin-Induced Renal Injury in Rats by Targeting Renal Endocytosis, SIRT1/Nrf2/HO-1, TLR-4/NF-κB/MAPK, and PI3K/Akt Cascades

“…In contrast, shikonin treatment in the gentamicin-induced kidney injury group significantly reduced the increased urinary albumin and calcium in a dose-dependent manner. These capabilities may be attributed to the increased NHE3 expression, which restores the competed megalin/cubilin complex activity in the proximal convoluted tubules, as well as shikonin's nephroprotective effect against gentamicin-induced glomerular and tubular dysfunction via PMK2 inhibition, enhanced renal antioxidant defense mechanisms, and inhibition of renal apoptosis, which restores standard glomerular filtration and tubular reabsorption [13,14].…”

“…Shikonin has recently attracted attention due to its potential multiple pharmacological activities, including anti-inflammatory, anti-cancer, cardioprotective, antimicrobial, analgesic, and neuroprotective potentialities [12]. In addition, shikonin also demonstrated nephroprotective properties in diabetic nephropathy and lethal endotoxemia animal models by activating the renal nuclear factorerythroid factor 2-related factor 2 (Nrf2) cascade and the antioxidant defense system, as well as decreasing circulating pro-inflammatory cytokines (Interleukin (IL)-6 and tumor necrosis factor (TNF)-α), and HIF-1 expression, along with inhibiting apoptosis, PKM2, NLRP3/caspase-1/IL-1β inflammasome, and improving animal survival [13][14][15][16][17]. Moreover, Shikonin is a chloride channels (CLC) inhibitor [18], so we hypothesized that it might suppress renal ClC-5, essential in megalin endocytosis, thus reducing endocytic function induced by gentamicin.…”