Klotho-derived peptide 1 inhibits cellular senescence in the fibrotic kidney by restoring Klotho expression via posttranscriptional regulation

Background: Klotho deficiency is a common feature of premature aging and chronic kidney disease (CKD). As such, restoring Klotho expression could be a logic strategy for protecting against various nephropathies. In this study, we demonstrate that KP1, a Klotho-derived peptide, inhibits cellular senescence by restoring endogenous Klotho expression. Methods: The effects of KP1 on cellular senescence and Klotho expression were assessed in mouse models of CKD. RNA-sequencing was employed to identify the microRNA involved in regulating Klotho by KP1. Gain- or loss-of-function approaches were used to assess the role of miR-223-3p and IncRNA-TUG1 in regulating Klotho and cellular senescence. Results: KP1 inhibited senescence markers p21, p16 and γ-H2AX in tubular epithelial cells of diseased kidneys, which was associated with its restoration of Klotho expression at the posttranscriptional level. Profiling of kidney microRNAs by RNA sequencing identified miR-223-3p that bound to Klotho mRNA and inhibited its protein expression. Overexpression of miR-223-3p inhibited Klotho and induced p21, p16 and γ-H2AX, which were negated by KP1. Conversely, inhibition of miR-223-3p restored Klotho expression, inhibited cellular senescence. Furthermore, miR-223-3p interacted with lncRNA-TUG1 and inhibited its expression. Knockdown of lncRNA-TUG1 increased miR-223-3p, aggravated Klotho loss and worsened cellular senescence, whereas KP1 mitigated all these changes. Conclusion: These studies demonstrate that KP1 inhibits cellular senescence and induces Klotho expression via posttranscriptional regulation mediated by miR-223-3p and lncRNA-TUG1. By restoring endogenous Klotho, KP1 elicits a broad spectrum of protective actions and could serve as a promising therapeutic agent for fibrotic kidney disorders.

Annexin A8 regulated by lncRNA-TUG1/miR-140-3p axis promotes bladder cancer progression and metastasis

Bladder cancer is the ninth most diagnosed cancer in the world. This study aims to investigate the role and mechanisms of the taurine-upregulated gene 1 (TUG1)/miR-140-3p/annexin A8 (ANXA8) axis in bladder cancer. Western blotting and qRT-PCR determined the expression levels of ANXA8, miR-140-3p, TUG1, and epithelial-mesenchymal transition (EMT) markers. RNA immunoprecipitation (RIP), luciferase assay, and RNA pull-down assay validated the association among ANXA8, miR-140-3p, and TUG1. The biological functions were determined by colony formation, Annexin V-fluorescein isothiocyanate (FITC)/propidium (PI) staining, and transwell assays. Xenograft tumorigenesis detected tumor growth and metastasis in vivo. Pathological analysis was examined by hematoxylin and eosin (H&E) and immunohistochemistry (IHC) analyses. ANXA8 was elevated in bladder tumors and cells. Knockdown of ANXA8 suppressed cell growth, migration, invasion, and EMT in UMUC-3 and T24 cells. ANXA8 was determined as a miR-140-3p target gene. Overexpression of miR-140-3p suppressed cell proliferation, migration, invasion, and EMT via targeting ANXA8. TUG1 promoted ANXA8 expression via sponging miR-140-3p. Silencing of miR-140-3p or ANXA8 overexpression abrogated the tumor-suppressive effects of TUG1 silencing on bladder cancer cell growth and metastasis. The TUG1/miR-140-3p/ANXA8 axis was also implicated in tumor growth and lung metastasis in vivo. TUG1 promotes bladder cancer progression and metastasis through activating ANXA8 by sponging miR-140-3p, which sheds light on the mechanisms of bladder cancer pathogenesis.

The lncRNA TUG1 promotes cell growth and migration in colorectal cancer via the TUG1-miR-145-5p-TRPC6 pathway

Colorectal cancer (CRC) is the third-most prevalent malignant tumor. Taurine upregulated gene 1 (TUG1), a long non-coding RNA (lncRNA), is reportedly involved in the physiological and pathological processes of CRC. However, the role of TUG1 in the progression of CRC and its underlying mechanisms are largely unknown. Here, we measured the expression of TUG1 in clinical samples from CRC patients and found that the expression level of TUG1 was higher in CRC tissues compared with the normal adjacent tissues. We then performed knockdown of TUG1 with siRNAs in two CRC cell lines and found that TUG1 knockdown inhibited the viability, proliferation, and migration of CRC cells, and reduced the ability of CRC cells to form subcutaneous tumors. Furthermore, we discovered that TUG1 affects the cellular processes in CRC cells by sponging miR-145-5p. We further found that miR-145-5p inhibits the expression of the protein-encoding gene Transient Receptor Potential Cation Channel Subfamily C Member 6 (TRPC6), and that overexpression of TRPC6 restored the inhibitory role of miR-145-5p in CRC cells. In conclusion, we have demonstrated that TUG1 exerts its role by modulating the TUG1-miR-145-5p-TRPC6 regulatory axis, thus revealing a novel molecular mechanism for the effects of TUG1 in the progression of CRC. Our data indicate that the TUG1-miR-145-5p-TRPC6 signaling pathway could serve as a target for the diagnosis and treatment of CRC.

Diosmetin alleviates acute kidney injury by promoting the TUG1/Nrf2/HO-1 pathway in sepsis rats

BACKGROUND

We aimed to study the effects and the underlying mechanisms of Diosmetin (DIOS) in rats with sepsis-induced acute kidney injury (AKI).

METHODS

The AKI model in RMCs was induced using LPS, and the cells were then treated with DIOS. Cell viability, apoptosis, inflammatory response, and antioxidant were measured using MTT, Flow cytometry, ELISA, and Lucigenin assay, respectively. The correlation between TUG1 and Nrf2 was confirmed by RNA pull-down and RNA immunoprecipitation. Real-time quantitative PCR and Western blot were performed to detect the expressions of gene and proteins during the development of AKI. The effects of lncRNA-TUG1 silencing and Nrf2 silencing on cell physiological functions were detected. Moreover, a rat sepsis-induced AKI model followed by Hematoxylin & Eosin (H&E) and immunofluorescence staining were performed.

RESULTS

The experimental concentration of DIOS was determined to be 20 μM. After LPS treatment, the activity of RMCs was decreased, the apoptosis rate, inflammation and oxidative stress damage were increased, moreover, the expression of Nrf2/HO-1 signal axis was inhibited and caspase-3 was activated. However, DIOS significantly reversed these effects caused by LPS treatment, and increased the expression of lncRNA-TUG1, but lncRNA-TUG1 silencing effectively reversed the effects of DIOS. In addition, lncRNA-TUG1 was found to interact with Nrf2. Overexpression of TUG1 could reduce the damage of LPS caused to cell physiological functions, which were reversed by siNrf2. Thus, DIOS treatment could improve the physiological and pathological damages of renal tissues in AKI rats.

CONCLUSION

DIOS may reduce sepsis-induced AKI through enhancing the TUG1/Nrf2/HO-1 pathway.

Chlorogenic acid relieved oxidative stress injury in retinal ganglion cells through IncRNA-TUG1/Nrf2

Objective: To discover the possible underlying mechanism of Chlorogenic acid (CGA) in protecting against oxidative stress injury in glaucoma. Methods: LncRNA TUG1 and Nrf2 expressions were detected by qRT-PCR and Western blot. Retinal ganglion cell (RGC) viability and apoptosis were measured by MTT and flow cytometry, respectively. Reactive oxygen species (ROS) level was determined by reactive oxygen species assay kit. The interaction between lncRNA TUG1 and Nrf2 was confirmed by RNA pull-down and RIP assay. Results: IPL thickness and lncRNA TUG1 expression were significantly decreased in glaucoma mice model, and CGA treatment increased IPL thickness and lncRNA TUG1 expression. In vitro H2O2-induced RGCs, RGC viability was significantly decreased, and ROS level and cell apoptosis were significantly increased. CGA up-regulated lncRNA TUG1 and Nrf2 expressions, decreased cell apoptosis and ROS production in RGCs, and increased RGCs viability. We further verified the interaction between lncRNA TUG1 and Nrf2, and proved Nrf2 was positively regulated by lncRNA TUG1. We found CGA promoted Nrf2 expression through lncRNA-TUG1, and further verified CGA protected RGCs from oxidative stress through regulating lncRNA TUG1/Nrf2. In vivo experiments showed TUG1 knockdown abrogated therapeutic effect of CGA on glaucoma. Conclusion: CGA increased RGC viability and decreased ROS level and RGC apoptosis after oxidative stress injury through lncRNA TUG1/Nrf2 pathway, which protected against glaucoma.

TUG1 is involved in liver fibrosis and activation of HSCs by regulating miR-29b

TUG1 has been shown to be involved in diverse human diseases by regulating gene expression at transcriptional and post-transcriptional levels via interaction with miRNA or proteins. However, the role of TUG1 in liver fibrosis remains unclear. Here, we found that Tug1 is dysregulated in liver fibrosis according to the microarray analysis. Moreover, we investigated the expression files of Tug1 by using CCl₄-and BDL-induced liver fibrosis model mice as well as in the primary cells isolated from the mice. We demonstrated that Tug1 is over-expressed in the fibrotic livers and activated HSCs, but not injured hepatocytes. In addition, we assessed the function of Tug1 in HSCs and found that Tug1 promotes the expression of α-SMA, Col1α1, Mmp2/9/10 and Timp1. Mechanically, Tug1 promotes the expression of these pro-fibrogenic genes by down-regulating miR-29b, thus accelerating the progression of liver fibrosis. Further study revealed that TUG1was up-regulated in liver tissues of patients with cirrhosis. All together, our data indicate that TUG1 might be a potential therapy target of liver fibrosis.