Age-related GSK3β overexpression drives podocyte senescence and glomerular aging
Yudong Fang, … , Lance D. Dworkin, Rujun Gong
Yudong Fang, … , Lance D. Dworkin, Rujun Gong
Published February 15, 2022
Citation Information: J Clin Invest. 2022;132(4):e141848. https://doi.org/10.1172/JCI141848.
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Research Article Aging Nephrology Article has an altmetric score of 109

Age-related GSK3β overexpression drives podocyte senescence and glomerular aging

Abstract

As life expectancy continues to increase, clinicians are challenged by age-related renal impairment that involves podocyte senescence and glomerulosclerosis. There is now compelling evidence that lithium has a potent antiaging activity that ameliorates brain aging and increases longevity in Drosophila and Caenorhabditis elegans. As the major molecular target of lithium action and a multitasking protein kinase recently implicated in a variety of renal diseases, glycogen synthase kinase 3β (GSK3β) is overexpressed and hyperactive with age in glomerular podocytes, correlating with functional and histological signs of kidney aging. Moreover, podocyte-specific ablation of GSK3β substantially attenuated podocyte senescence and glomerular aging in mice. Mechanistically, key mediators of senescence signaling, such as p16INK4A and p53, contain high numbers of GSK3β consensus motifs, physically interact with GSK3β, and act as its putative substrates. In addition, therapeutic targeting of GSK3β by microdose lithium later in life reduced senescence signaling and delayed kidney aging in mice. Furthermore, in psychiatric patients, lithium carbonate therapy inhibited GSK3β activity and mitigated senescence signaling in urinary exfoliated podocytes and was associated with preservation of kidney function. Thus, GSK3β appears to play a key role in podocyte senescence by modulating senescence signaling and may be an actionable senostatic target to delay kidney aging.

Authors

Yudong Fang, Bohan Chen, Zhangsuo Liu, Athena Y. Gong, William T. Gunning, Yan Ge, Deepak Malhotra, Amira F. Gohara, Lance D. Dworkin, Rujun Gong

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Figure 6

GSK3β regulates the phosphorylation of p16INK4A and p53, resulting in modulation of senescence signaling in podocytes.

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GSK3β regulates the phosphorylation of p16INK4A and p53, resulting in mo...
Conditionally immortalized murine podocytes were transiently lipotransfected with a control empty plasmid vector (EV), or plasmids encoding the HA-conjugated dominant-negative kinase dead (KD) mutant of GSK3β or constitutively active (S9A) mutant of GSK3β in the presence or absence of lithium chloride (LiCl, 10 mM) or an equal volume of vehicle. (A) After different treatments, cells were subjected to immunofluorescent staining for HA, which revealed a transfection efficiency of approximately 80%. Scale bar: 20 μm. (B) Whole cell lysates were processed for immunoprecipitation (IP) by using an anti-p16INK4A or -p53 antibody, followed by immunoblot analysis (IB) of immunoprecipitates for phosphorylated serine (p-Ser), in parallel with input controls. (C) Representative immunoblot analysis of cell lysates for indicated molecules. β-Tubulin served as a loading control. (D) Cells were subjected to SA-β-gal activity staining, or to immunofluorescent staining for synaptopodin (SYNPO; red) or γH2AX (green) followed by counterstaining with DAPI for nuclei or with rhodamine-phalloidin for F-actin (red). Scale bars: 20 μm. (E) Absolute count of the number of γH2AX+ cells as percentages of the total number of cells per microscopic field. *P < 0.05 versus all other groups (n = 3). (F) Quantification of the SA-β-gal+ cells as percentages of the total number of cells per microscopic field. **P < 0.01 versus all other groups (n = 3). Data are expressed as mean ± SD. Panels E and F were analyzed by 1-way ANOVA followed by Tukey’s test.