β‐Amyrin ameliorates diabetic nephropathy in mice and regulates the miR‐181b‐5p/HMGB2 axis in high glucose‐stimulated HK‐2 cells

Abstract

Diabetic nephropathy (DN) is a diabetic complication that can cause renal failure. β‐amyrin has been identified to possess anti‐diabetic property. This study was designed to evaluate the potential role of β‐amyrin in DN and its underlying mechanism. Streptozotocin‐induced diabetic mice were used as the in vivo model, and high glucose (HG)‐stimulated human proximal tubular HK‐2 cells were utilized as the in vitro model. Renal histological changes in mice were assessed by hematoxylin–eosin and periodic acid‐Schiff staining. HK‐2 cell viability and apoptosis were detected by Cell Counting Kit‐8 assay and flow cytometry analysis, respectively. β‐amyrin was found to ameliorate kidney injury in DN mice and suppressed inflammatory response as well as apoptosis of HG‐stimulated HK‐2 cells. miR‐181‐5p expression in murine renal tissues and HK‐2 cells was detected by in situ hybridization (ISH) and fluorescence in situ hybridization (FISH). MiR‐181b‐5p, a previously identified target for diabetic kidney disease, was downregulated in renal tissues and HG stimulated HK‐2 cells, and β‐amyrin induced the upregulation of miR‐181b‐5p. Binding relationship between miR‐181b‐5p and high mobility group box 2 (HMGB2) was confirmed by luciferase reporter assay. MiR‐181b‐5p bound to 3′ untranslated region of HMGB2 to suppress its expression. As shown by immunohistochemical staining and immunofluorescence staining, HMGB2 was upregulated in the in vivo and in vitro models of DN, and β‐amyrin induced the downregulation of HMGB2. Moreover, HMGB2 overexpression neutralized the suppressive effects of miR‐181b‐5p elevation on the inflammatory response and apoptosis of HG‐treated HK‐2 cells. Overall, β‐amyrin ameliorates DN in mice and suppresses inflammatory response and apoptosis of HG‐stimulated HK‐2 cells via the miR‐181b‐5p/HMGB2 axis.

Analysis of the human kidney transcriptome and plasma proteome identifies markers of proximal tubule maladaptation to injury

“…Consistent with the profibrotic and pro-inflammatory signatures from GSEA, maladaptive PT up-regulated TEA domain transcription factor 2 (TEAD2), a regulator governing the epithelial-to-mesenchymal transition, and interferon regulatory factor 8 (IRF8), a transcription factor promoting inflammatory responses (22,23). As a comparison, severely injured PT cells activated regulators of the response to an inflammatory milieu [CEBPB and high mobility group box 2 (HMGB2)] as well as regulators driving endoplasmic reticulum stress (HES1 and XBP1) and apoptosis in diseased states (HMGB2 and IRF6) (24)(25)(26)(27). The expression of regulons across PT cells in healthy and diseased states was consistent with the cellular enrichment estimated from pySCENIC (Fig.…”

The Glomerulus Multiomics Analysis Provides Deeper Insights into Diabetic Nephropathy

“…Detailed examination of these TFs revealed that several of them are well-known regulators in the pathological process of DN. For instance, RELA (NF-kB p65, the canonical NF-κB component) and HMGB2 were reported to be upregulated in the in vivo and in vitro models of DN, and their activation promoted inflammatory response and apoptosis. , The proliferation-related biomarkers of PCNA were significantly elevated in a high-glucose environment . Additionally, AEBP1 is the integration center of the downstream DN-associated genes involved in collagen fibril organization, extracellular matrix organization, and cell adhesion, and Tao et al found that the AEBP1 level was positively correlated with 24 h proteinuria and negatively correlated with eGFR .…”

Intestinal Absorption of Nanoparticles to Reduce Oxidative Stress and Vasoconstriction for Treating Diabetic Nephropathy

“…Among them, the oxidative stress caused by high glucose is one of the main pathogenesis of DN. − Oxidative stress generates excess reactive oxygen species (ROS), which stimulates abnormal accumulation of extracellular matrix proteins in the kidney, thereby leading to renal glomerulosclerosis and tubulointerstitial fibrosis. , Meanwhile, high glucose promotes the synthesis of angiotensin II (Ang II), and the increase in Ang II level directly causes the constriction of blood vessels and the increase of glomerular pressure . The studies have shown that high glucose induces changes in the expression level of apoptosis-related proteins in HK-2 cells, which promotes cell apoptosis. − …”