Published online Mar 15, 2024. doi: 10.4239/wjd.v15.i3.488
Peer-review started: August 31, 2023
First decision: December 25, 2023
Revised: January 6, 2024
Accepted: January 29, 2024
Article in press: January 29, 2024
Published online: March 15, 2024
Processing time: 197 Days and 5.3 Hours
Diabetic kidney disease (DKD) is a major complication of diabetes mellitus. Numerous studies have demonstrated that tubular epithelial cell (TEC) damage, which is strongly associated with the inflammatory response and mesenchymal trans-differentiation, plays a significant role in DKD; however, the precise molecular mechanism is unknown. The recently identified microRNA-630 (miR-630) has been hypothesized to be closely associated with cell migration, apoptosis, and autophagy.
The relationship between miR-630 and DKD and the underlying mechanism remains unknown.
The object of this study is to investigate how miR-630 affects TEC injury and the inflammatory response in DKD rats.
Streptozotocin was administered to six-week-old male rats to create a hyperglycemic diabetic model, and in the second week of modeling, the rats were divided into control, DKD, negative control lentivirus, and miR-630 overexpression groups. After eight weeks, urine and blood samples were collected for the kidney injury assay, and renal tissues were removed for further molecular assays, such as real-time polymerase chain reaction, western blotting, enzyme-linked immunosorbent assay, and immunohistochemistry. The target gene for miR-630 was predicted using bioinformatics, and in vitro investigations and double luciferase reporter gene assays confirmed the association between miR-630 and toll-like receptor 4 (TLR4).
The expression level of miR-630 was decreased in the kidney tissue of rats with DKD (P < 0.05). In vitro experiments, the mRNA expression level of miR-630 was significantly lower in the high glucose (HG) and HG + mimic negative control (NC) groups than in the normal glucose group (P < 0.05). In contrast, the mRNA expression level of TLR4 was significantly higher in these groups (P < 0.05). The HG and HG + mimic NC groups showed a significant decrease in E-cadherin protein expression, whereas TLR4, α-smooth muscle actin (SMA), and collagen IV protein expression increased (P < 0.05). Conversely, compared with the HG + mimic NC group, a significant increase in E-cadherin protein expression and a notable decrease in TLR4, α-SMA, and collagen IV protein expression were observed in the HG + miR-630 mimic group (P < 0.05). In vivo experiments, DKD rats treated with miR-630 agomir exhibited significantly higher miR-630 mRNA expression than DKD rats injected with agomir NC. Additionally, rats treated with miR-630 agomir showed significant reductions in urinary albumin, blood glucose, TLR4, and proinflammatory markers (TNF-α, IL-1β, and IL-6) expression levels (P < 0.05). Moreover, these rats exhibited fewer kidney lesions and reduced infiltration of inflammatory cells.
The miR-630 may inhibit the inflammatory reaction in DKD by targeting TLR4, and has a protective effect on DKD.
The follow-up study needs to further confirm the expression difference of clinical human blood, urine or kidney tissue in diabetic nephropathy patients and its relationship with DKD staging, and further clarify the regulatory mechanism of its upstream signal pathway.