Circ-PRKCI Alleviates Lipopolysaccharide-induced Human Kidney 2 Cell Injury by Regulating miR-106b-5p/GAB1 Axis

Abstract

Circular RNAs act as vital regulators in diverse diseases.However, the investigation of circular RNAs in sepsis-engendered acute kidney injury remains dismal. We aimed to explore the effects of circular RNA protein kinase C iota (circ-PRKCI) in lipopolysaccharide (LPS)-mediated HK2 cell injury. Sepsis in vitro model was established by LPS treatment. Quantitative real-time polymerase chain reaction assay was conducted for determining the levels of circ-PRKCI, microRNA-106b-5p (miR-106b-5p), and growth factor receptor binding 2-associated binding protein 1 (GAB1). Cell viability and apoptosis were evaluated using Cell Counting Kit-8 assay and flow cytometry analysis, respectively. The concentrations of interleukin-6, interleukin-1b, and tumor necrosis factor-a were measured with enzyme-linked immunosorbent assay kits. The levels of oxidative stress markers were determined using relevant commercial kits. Western blot assay was conducted for B-cell lymphoma-2 (Bcl-2), BCL2-Associated X (Bax), and GAB1 protein levels. Dualluciferase reporter assay and RNA immunoprecipitation assay were used to verify the association between miR-106b-5p and circ-PRKCI or GAB1. We found the Circ-PRKCI level was decreased in sepsis patients and LPS-induced human kidney 2 (HK-2) cells. LPS exposure inhibited cell viability and facilitated apoptosis, inflammation, and oxidative stress in HK-2 cells. Circ-PRKCI overexpression abrogated the effects of LPS on cell apoptosis, inflammation, and oxidative stress in HK-2 cells. Furthermore, circ-PRKCI was identified as the sponge for miR-106b-5p to positively regulate GAB1 expression. Overexpression of circ-PRKCI relieved LPS-mediated HK-2 cell damage by sponging miR-106b-5p. MiR-106b-5p inhibition ameliorated the injury of HK-2 cells mediated by LPS, whereas GAB1 knockdown reversed the effect. Collectively, Circ-PRKCI overex-pression attenuated LPS-induced HK-2 cell injury by regulating miR-106b-5p/GAB1 axis.

Inhibition of sepsis‐induced acute kidney injury via thecircITCH‐miR‐579‐3p‐ZEB2axis

“…Up to now, accumulating evidence has indicated that exceptionally expressed circRNAs are implicated in the development of sepsis‐associated AKI. For instance, circVMA21 or circPRKCI overexpression 25,26 and circFANCA silencing 27 are capable of inhibiting apoptosis and inflammation in LPS‐stimulated septic AKI in a ceRNA manner. Our study for the first time demonstrated that circITCH was underexpressed in serum of patients with sepsis‐induced AKI and LPS‐induced HK‐2 cells.…”

“…23,24 Up to now, accumulating evidence has indicated that exceptionally expressed circRNAs are implicated in the development of sepsis-associated AKI. For instance, circVMA21 or circPRKCI overexpression 25,26 28 gastric cancer, 29 osteosarcoma, 30 and glioma 31 as well as nasopharyngeal carcinoma. 32 The cardioprotective effects of circITCH against H 2 O 2 or doxorubicin-induced myocardial injury were recently reported by Zhang et al 19 and Han et al, 20 respectively.…”

Circusp42 Ameliorates LPS-Induced Human Renal Epithelial Cells in Vitro by Regulating the Mir-182-5p/Dusp1 Axis

“…A large number of studies had shown that many newly discovered circRNAs were involved in the regulation of AKI caused by sepsis (31). For instance, overexpression of circ-PRKCI upregulated GAB1 by combining miR-106b-5p to inhibit LPS damage to HK-2 cells, including inhibition of apoptosis, inflammation, and oxidative stress (13). It was known that circUSP42 was downregulated in the serum of patients with AKI caused by sepsis (20), but the function and regulation mechanism of circUSP42 needed to be explored in depth.…”

“…Accumulating studies constructed sepsis-induced AKI cell models with LPS treatment and asserted that inflammatory response, oxidative stress, and other body responses that are extremely related to the development of AKI (10), which were participated by a variety of molecules, including circRNAs (11). Numerous evidences indicated that circRNAs, as competitive endogenous RNA, regulated target gene expression at the transcription and translation level via combining miRNAs to participate in the progress of AKI (12)(13)(14). For example, circ-FANCA knockdown reduced the damage of HK2 cells induced by LPS by regulating the miR-93-5p/OXSR1 axis (15).…”

Circular RNAs in Acute Kidney Injury: Roles in Pathophysiology and Implications for Clinical Management

“…Likewise, circ-PRKCI was decreased in patients with septic AKI and in LPS-simulated HK-2 cells. Circ-PRKC1 likely acts as a sponge for miR-106b-5p to regulate the expression of growth factor receptor binding 2-associated binding protein 1 (GAB1), a protein that has been associated with tissue damage in acute lung injury; the overexpression of circ-PRKCI had salutary effects on cell apoptosis and inflammation [ 41 ]. In a rat CLP model of septic AKI, circ-Ttc3 was downregulated in kidney samples with the resultant overexpression of miR-148a.…”