DNA repair factor KAT5 prevents ischemic acute kidney injury through glomerular filtration regulation

Predicting exacerbation of renal function by DNA methylation clock and DNA damage of urinary shedding cells: a pilot study

Recent reports have shown the feasibility of measuring biological age from DNA methylation levels in blood cells from specific regions identified by machine learning, collectively known as the epigenetic clock or DNA methylation clock. While extensive research has explored the association of the DNA methylation clock with cardiovascular diseases, cancer, and Alzheimer's disease, its relationship with kidney diseases remains largely unexplored. In particular, it is unclear whether the DNA methylation clock could serve as a predictor of worsening kidney function. In this pilot study involving 20 subjects, we investigated the association between the DNA methylation clock and subsequent deterioration of renal function. Additionally, we noninvasively evaluated DNA damage in urinary shedding cells using a previously reported method to examine the correlation with the DNA methylation clock and worsening kidney function. Our findings revealed that patients with an accelerated DNA methylation clock exhibited increased DNA damage in urinary shedding cells, along with a higher rate of eGFR decline. Moreover, in cases of advanced CKD (G4-5), the DNA damage in urinary shedding cells was significantly increased, highlighting the interplay between elevated DNA damage and eGFR decline. This study suggests the potential role of the DNA methylation clock and urinary DNA damage as predictive markers for the progression of chronic kidney disease.

STUB1 is acetylated by KAT5 and alleviates myocardial ischemia-reperfusion injury through LATS2-YAP-β-catenin axis

Myocardial ischemia-reperfusion injury (MIRI) is involved in the pathogenesis of multiple cardiovascular diseases. This study elucidated the biological function of lysine acetyltransferase 5 (KAT5) in cardiomyocyte pyroptosis during MIRI. Oxygen-glucose deprivation/reoxygenation and left anterior descending coronary artery ligation were used to establish MIRI models. Here we show, KAT5 and STIP1 homology and U-box-containing protein 1 (STUB1) were downregulated, while large tumor suppressor kinase 2 (LATS2) was upregulated in MIRI models. KAT5/STUB1 overexpression or LATS2 silencing repressed cardiomyocyte pyroptosis. Mechanistically, KAT5 promoted STUB1 transcription via acetylation modulation, and subsequently caused ubiquitination and degradation of LATS2, which activated YAP/β-catenin pathway. Notably, the inhibitory effect of STUB1 overexpression on cardiomyocyte pyroptosis was abolished by LATS2 overexpression or KAT5 depletion. Our findings suggest that KAT5 overexpression inhibits NLRP3-mediated cardiomyocyte pyroptosis to relieve MIRI through modulation of STUB1/LATS2/YAP/β-catenin axis, providing a potential therapeutic target for MIRI.

Berberine alleviates ischemia reperfusion injury induced AKI by regulation of intestinal microbiota and reducing intestinal inflammation

BACKGROUND

It has been found that a variety of host disease states can exacerbate intestinal inflammation, leading to disruption of intestinal barrier function. Changes in the composition of the intestine microbiota, which affect downstream metabolites in turn, ultimately react against the host.

OBJECTIVES

We revealed the mechanism of berberine as an intestinal protective agent in rats with renal ischemia-reperfusion injury acute kidney injury (AKI).

METHODS

HE staining was performed to evaluate the pathological changes in the colon and kidney. 16 S rRNA analysis was performed to assess the intestinal microbiota. Intestine TLR4/NF-κB expression was assessed by western blot. Q-RT-PCR was performed to detect TLR4 in intestine and IL-6 and KIM-1 gene expression in the kidney. SPSS 22.0 was used to compare the data.

RESULTS

Rats with AKI exhibited increased relative abundances of Proteobacteria and Bacteroidetes and decreased relative abundances of Lactobacillus, Ruminococcus and Lachnospiraceae belonging to the phylum Firmicutes. The Sirt1-NF-κB-TLR4 pathway was involved in the occurrence process, accompanied by intestinal inflammation and oxidation. Berberine reversed the appeal change.

CONCLUSION

Berberine inhibits the intestinal biological barrier of Proteobacteria, reduces LPS production, exerts an anti-inflammatory effect, and delays the progression of AKI.

Biotherapy of experimental acute kidney injury: emerging novel therapeutic strategies

Acute kidney injury (AKI) is a complex and heterogeneous disease with high incidence and mortality, posing a serious threat to human life and health. Usually, in clinical practice, AKI is caused by crush injury, nephrotoxin exposure, ischemia-reperfusion injury, or sepsis. Therefore, most AKI models for pharmacological experimentation are based on this. The current research promises to develop new biological therapies, including antibody therapy, non-antibody protein therapy, cell therapy, and RNA therapy, that could help mitigate the development of AKI. These approaches can promote renal repair and improve systemic hemodynamics after renal injury by reducing oxidative stress, inflammatory response, organelles damage, and cell death, or activating cytoprotective mechanisms. However, no candidate drugs for AKI prevention or treatment have been successfully translated from bench to bedside. This article summarizes the latest progress in AKI biotherapy, focusing on potential clinical targets and novel treatment strategies that merit further investigation in future pre-clinical and clinical studies.

Targeting DNA Methylation in Podocytes to Overcome Chronic Kidney Disease

The number of patients with chronic kidney disease (CKD) is on the rise worldwide, and there is urgent need for the development of effective plans against the increasing incidence of CKD. Podocytes, glomerular epithelial cells, are an integral part of the primary filtration unit of the kidney and form a slit membrane as a barrier to prevent proteinuria. The role of podocytes in the pathogenesis and progression of CKD is now recognized. Podocyte function depends on a specialized morphology with the arranged foot processes, which is directly related to their function. Epigenetic changes responsible for the regulation of gene expression related to podocyte morphology have been shown to be important in the pathogenesis of CKD. Although epigenetic mechanisms include DNA methylation, histone modifications, and RNA-based regulation, we have focused on DNA methylation changes because they are more stable than other epigenetic modifications. This review summarizes recent literature about the role of altered DNA methylation in the kidney, especially in glomerular podocytes, focusing on transcription factors and DNA damage responses that are closely associated with the formation of DNA methylation changes.

Altered DNA methylation in kidney disease: useful markers and therapeutic targets

Recent studies have demonstrated the association of altered epigenomes with lifestyle-related diseases. Epigenetic regulation promotes biological plasticity in response to environmental changes, and such plasticity may cause a ‘memory effect’, a sustained effect of transient treatment or an insult in the course of lifestyle-related diseases. We investigated the significance of epigenetic changes in several genes required for renal integrity, including the nephrin gene in podocytes, and the sustained anti-proteinuric effect, focusing on the transcription factor Krüppel-like factor 4 (KLF4). We further reported the role of the DNA repair factor lysine-acetyl transferase 5 (KAT5), which acts coordinately with KLF4, in podocyte injury caused by a hyperglycemic state through the acceleration of DNA damage and epigenetic alteration. In contrast, KAT5 in proximal tubular cells prevents acute kidney injury via glomerular filtration regulation by an epigenetic mechanism as well as promotion of DNA repair, indicating the cell type-specific action and roles of DNA repair factors. This review summarizes epigenetic alterations in kidney diseases, especially DNA methylation, and their utility as markers and potential therapeutic targets. Focusing on transcription factors or DNA damage repair factors associated with epigenetic changes may be meaningful due to their cell-specific expression or action. We believe that a better understanding of epigenetic alterations in the kidney will lead to the development of a novel strategy for chronic kidney disease (CKD) treatment.