KLF11 deficiency enhances chemokine generation and fibrosis in murine unilateral ureteral obstruction

Endothelial KLF11 is a novel protector against diabetic atherosclerosis

BACKGROUND

Atherosclerotic cardiovascular diseases remain the leading cause of mortality in diabetic patients, with endothelial cell (EC) dysfunction serving as the initiating step of atherosclerosis, which is exacerbated in diabetes. Krüppel-like factor 11 (KLF11), known for its missense mutations leading to the development of diabetes in humans, has also been identified as a novel protector of vascular homeostasis. However, its role in diabetic atherosclerosis remains unexplored.

METHODS

Diabetic atherosclerosis was induced in both EC-specific KLF11 transgenic and knockout mice in the Ldlr-/- background by feeding a diabetogenic diet with cholesterol (DDC). Single-cell RNA sequencing (scRNA-seq) was utilized to profile EC dysfunction in diabetic atherosclerosis. Additionally, gain- and loss-of-function experiments were conducted to investigate the role of KLF11 in hyperglycemia-induced endothelial cell dysfunction.

RESULTS

We found that endothelial KLF11 deficiency significantly accelerates atherogenesis under diabetic conditions, whereas KLF11 overexpression remarkably inhibits it. scRNA-seq profiling demonstrates that loss of KLF11 increases endothelial-to-mesenchymal transition (EndMT) during atherogenesis under diabetic conditions. Utilizing gain- and loss-of-function approaches, our in vitro study reveals that KLF11 significantly inhibits EC inflammatory activation and TXNIP-induced EC oxidative stress, as well as Notch1/Snail-mediated EndMT under high glucose exposure.

CONCLUSION

Our study demonstrates that endothelial KLF11 is an endogenous protective factor against diabetic atherosclerosis. These findings indicate that manipulating KLF11 could be a promising approach for developing novel therapies for diabetes-related cardiovascular complications.

SKP2-mediated ubiquitination and degradation of KLF11 promotes osteoarthritis via modulation of JMJD3/NOTCH1 pathway

Osteoarthritis (OA) is the main cause of cartilage damage and disability. This study explored the biological function of S-phase kinase-associated protein 2 (SKP2) and Kruppel-like factor 11 (KLF11) in OA progression and its underlying mechanisms. C28/I2 chondrocytes were stimulated with IL-1β to mimic OA in vitro. We found that SKP2, Jumonji domain-containing protein D3 (JMJD3), and Notch receptor 1 (NOTCH1) were upregulated, while KLF11 was downregulated in IL-1β-stimulated chondrocytes. SKP2/JMJD3 silencing or KLF11 overexpression repressed apoptosis and extracellular matrix (ECM) degradation in chondrocytes. Mechanistically, SKP2 triggered the ubiquitination and degradation of KLF11 to transcriptionally activate JMJD3, which resulted in activation of NOTCH1 through inhibiting H3K27me3. What's more, the in vivo study found that KLF11 overexpression delayed OA development in rats via restraining apoptosis and maintaining the balance of ECM metabolism. Taken together, ubiquitination and degradation of KLF11 regulated by SKP2 contributed to OA progression by activation of JMJD3/NOTCH1 pathway. Our findings provide promising therapeutic targets for OA.

[Upregulating KLF11 ameliorates intestinal inflammation in mice with 2, 4, 6-trinitrobenesulfonic acid-induced colitis by inhibiting the JAK2/STAT3 signaling pathway]

OBJECTIVE

To investigate the expression level of Kruppel-like transcription factor family member KLF11 in intestinal mucosal tissues of Crohn's disease (CD) and its regulatory effect on intestinal inflammation in CD-like colitis.

METHODS

We examined KLF11 expression levels in diseased and normal colon mucosal tissues from 12 CD patients and 12 patients with colorectal cancer using immunofluorescence staining. KLF11 expression was also detected in the colon mucosal tissues of a mouse model of 2, 4, 6-trinitrobenesulfonic acid (TNBS)-induced colitis. A recombinant adenoviral vector was used to upregulate KLF11 expression in the mouse models and the changes in intestinal inflammation was observed. A Caco-2 cell model with stable KLF11 overexpression was constructed by lentiviral infection. The effect of KLF11 overexpression on expressions of JAK2/STAT3 signaling pathway proteins was investigated using immunoblotting in both the mouse and cell models. The mouse models were treated with coumermycin A1, a JAK2/STAT3 signaling pathway agonist, and the changes in intestinal inflammatory responses were observed.

RESULTS

The expression level of KLF11 was significantly lowered in both the clinical specimens of diseased colon mucosal tissues and the colon tissues of mice with TNBS-induced colitis (P < 0.05). Adenovirus-mediated upregulation of KLF11 significantly improved intestinal inflammation and reduced the expression levels of inflammatory factors in the intestinal mucosa of the colitis mouse models (P < 0.05). Overexpression of KLF11 significantly inhibited the expression levels of p-JAK2 and p-STAT3 in intestinal mucosal tissues of the mouse models and in Caco-2 cells (P < 0.05). Treatment with coumermycin A1 obviously inhibited the effect of KLF11 upregulation for improving colitis and significantly increased the expression levels of inflammatory factors in the intestinal mucosa of the mouse models (P < 0.05).

CONCLUSION

KLF11 is downregulated in the intestinal mucosa in CD, and upregulation of KLF11 can improve intestinal inflammation and reduce the production of inflammatory factors probably by inhibiting the JAK2/STAT3 signaling pathway.

Shared and Distinct Renal Transcriptome Signatures in 3 Standard Mouse Models of Chronic Kidney Disease

INTRODUCTION

Several mouse models with diverse disease etiologies are used in preclinical research for chronic kidney disease (CKD). Here, we performed a head-to-head comparison of renal transcriptome signatures in standard mouse models of CKD to assess shared and distinct molecular changes in three mouse models commonly employed in preclinical CKD research and drug discovery.

METHODS

All experiments were conducted on male C57BL/6J mice. Mice underwent sham, unilateral ureter obstruction (UUO), or unilateral ischemic-reperfusion injury (uIRI) surgery and were terminated two- and 6-weeks post-surgery, respectively. The adenine-supplemented diet-induced (ADI) model of CKD was established by feeding with adenine diet for 6 weeks and compared to control diet feeding. For all models, endpoints included plasma biochemistry, kidney histology, and RNA sequencing.

RESULTS

All models displayed increased macrophage infiltration (F4/80 IHC) and fibrosis (collagen 1a1 IHC). Compared to corresponding controls, all models were characterized by an extensive number of renal differentially expressed genes (≥11,000), with a notable overlap in transcriptomic signatures across models. Gene expression markers of fibrosis, inflammation, and kidney injury supported histological findings. Interestingly, model-specific transcriptome signatures included several genes representing current drug targets for CKD, emphasizing advantages and limitations of the three CKD models in preclinical target and drug discovery.

CONCLUSION

The UUO, uIRI, and ADI mouse models of CKD have significant commonalities in their renal global transcriptome profile. Model-specific renal transcriptional signatures should be considered when selecting the specific model in preclinical target and drug discovery.

Targeting DNA methylation in diabetic kidney disease: A new perspective

Diabetic kidney disease (DKD) is a leading diabetic complication causing significant mortality among people around the globe. People with poor glycemic control accompanied by hyperinsulinemia, dyslipidemia, hypertension, and obesity develop diabetic complications. These diabetic patients develop epigenetic changes and suffer from diabetic kidney complications even after subsequent glucose control, the phenomenon that is recognized as metabolic memory. DNA methylation is an essential epigenetic modification that contributes to the development and progression of several diabetic complications, including DKD. The aberrant DNA methylation pattern at CpGs sites within several genes, such as mTOR, RPTOR, IRS2, GRK5, SLC27A3, LCAT, and SLC1A5, associated with the accompanying risk factors exacerbate the DKD progression. Although drugs such as azacytidine and decitabine have been approved to target DNA methylation for diseases such as hematological malignancies, none have been approved for the treatment of DKD. More importantly, no DNA hypomethylation-targeting drugs have been approved for any disease conditions. Understanding the alteration in DNA methylation and its association with the disease risk factors is essential to target DKD effectively. This review has discussed the abnormal DNA methylation pattern and the kidney tissue-specific expression of critical genes involved in DKD onset and progression. Moreover, we also discuss the new possible therapeutic approach that can be exploited for treating DNA methylation aberrancy in a site-specific manner against DKD.

An integrated co-expression network analysis reveals novel genetic biomarkers for immune cell infiltration in chronic kidney disease

Background

Chronic kidney disease (CKD) is characterized by persistent damage to kidney function or structure. Progression to end-stage leads to adverse effects on multiple systems. However, owing to its complex etiology and long-term cause, the molecular basis of CKD is not completely known.

Methods

To dissect the potential important molecules during the progression, based on CKD databases from Gene Expression Omnibus, we used weighted gene co-expression network analysis (WGCNA) to identify the key genes in kidney tissues and peripheral blood mononuclear cells (PBMC). Correlation analysis of these genes with clinical relevance was evaluated based on Nephroseq. Combined with a validation cohort and receiver operating characteristic curve (ROC), we found the candidate biomarkers. The immune cell infiltration of these biomarkers was evaluated. The expression of these biomarkers was further detected in folic acid-induced nephropathy (FAN) murine model and immunohistochemical staining.

Results

In total, eight genes (CDCP1, CORO1C, DACH1, GSTA4, MAFB, TCF21, TGFBR3, and TGIF1) in kidney tissue and six genes (DDX17, KLF11, MAN1C1, POLR2K, ST14, and TRIM66) in PBMC were screened from co-expression network. Correlation analysis of these genes with serum creatinine levels and estimated glomerular filtration rate from Nephroseq showed a well clinical relevance. Validation cohort and ROC identified TCF21, DACH1 in kidney tissue and DDX17 in PBMC as biomarkers for the progression of CKD. Immune cell infiltration analysis revealed that DACH1 and TCF21 were correlated with eosinophil, activated CD8 T cell, activated CD4 T cell, while the DDX17 was correlated with neutrophil, type-2 T helper cell, type-1 T helper cell, mast cell, etc. FAN murine model and immunohistochemical staining confirmed that these three molecules can be used as genetic biomarkers to distinguish CKD patients from healthy people. Moreover, the increase of TCF21 in kidney tubules might play important role in the CKD progression.

Discussion

We identified three promising genetic biomarkers which could play important roles in the progression of CKD.

KLF11 Is a Novel Endogenous Protectant against Renal Ischemia-Reperfusion Injury

Discovering new nephroprotectants may provide therapeutic strategies in AKI.This study provides the first evidence that KLF11, a member of the Krüppel-like factor (KLF) family of proteins, protects against AKI.In the absence of KLF11, exaggerated induction of endothelin-1 and IL-6 occurs after ischemic renal injury and may contribute to worse AKI.