Metformin protects lens epithelial cells against senescence in a naturally aged mouse model

The senescence of lens epithelial cells (LECs) is a major factor leading to age-related cataract (ARC). ARC results in visual impairment and severe vision loss in elderly patients. However, the specific mechanism of ARC remains unclear, and there are no effective therapeutic agents to halt the formation of ARC. This study aimed to assess the underlying mechanism of the formation of ARC and investigate the potential anti-ageing effect of metformin (MET) on ARC. Male C57BL/6 mice were divided into three groups: the control group having young mice (3 months old, n = 40), the naturally aged group (aged 20 months, n = 60) and the MET group (MET, 20 months, n = 60). Mice in the control and the naturally aged groups were fed a standard purified mouse diet ad libitum and water, whereas those in the MET group were fed chows supplemented with 0.1% MET for 10 months. The transparency of the lens and age-associated proteins p21 and p53 were analysed in the LECs of these three groups. Furthermore, we determined the expressions of the adenosine monophosphate (AMP)-activated protein kinase (AMPK) pathway and the effect of MET on this pathway in LECs during the ageing process of ARC. In addition, the relationship between autophagy and the senescence of LECs and the role of MET in the autophagy of LECs during the ageing process of ARC were examined. Our results indicated that age-related inactivation of the AMPK pathway and impairment of autophagy might contribute to the senescence of LECs and the occurrence of ARC. More importantly, these results demonstrated that MET effectively alleviated the senescence of LECs and the formation of ARC probably via inactivation of the AMPK pathway and augmentation of autophagy. These findings revealed that MET can be exploited as a potentially useful drug for ARC prevention. Our study will help in enlightening the development of innovative strategies for the clinical treatment of ARC.

CircWHSC1 Promotes Breast Cancer Progression by Regulating the FASN/AMPK/mTOR Axis Through Sponging miR-195-5p

Numerous studies reveal that circular RNAs (circRNAs) affect cancer progression. CircWHSC1 is a novel circRNA that accelerates ovarian cancer progression. Nevertheless, the function of circWHSC1 in regulating breast cancer (BC) is elusive. Here, quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was carried out to detect the profiles of circWHSC1 and miR-195-5p in BC tissues and corresponding non-tumor tissues. Gain- and loss-of-function assays were implemented both in vivo and ex vivo to verify the significance of circWHSC1 in BC development. BC cell proliferation was estimated by the cell counting kit-8 (CCK-8) and BrdU assays. Transwell assay was implemented to test BC cell migration and invasion. The protein levels of FASN, AMPK and mTOR were determined by Western blot. Moreover, immunohistochemistry was performed to examine Ki67 and FASN expression. As shown by the result, circWHSC1 was up-regulated in BC tissues versus adjacent non-tumor tissues. circWHSC1 overexpression was correlated with higher tumor stages, lymphatic metastasis and worse survival of BC patients. Functionally, overexpressing circWHSC1 amplified proliferation, migration and invasion of BC cell lines and boosted xenograft tumor growth in nude mice. Bioinformatics uncovered that circWHSC1 functioned as a competitive endogenous RNA by sponging miR-195-5p, which was further corroborated by the dual-luciferase reporter assay and RNA immunoprecipitation. miR-195-5p delayed BC progression, which was dampened by circWHSC1 up-regulation. Fatty acid synthase (FASN) was affirmed as a direct target of miR-195-5p. miR-195-5p overexpression curbed FASN expression and activated its downstream AMPK pathway. Inhibition of FASN or activation of the AMPK pathway reversed circWHSC1-mediated oncogenic effects. Collectively, CircWHSC1 acted as an oncogene to expedite BC evolvement by modulating the miR-195-5p/FASN/AMPK/mTOR pathway.

Ginsenoside Rg3 alleviates septic liver injury by regulating the lncRNA TUG1/miR-200c-3p/SIRT1 axis

Background Studies have shown that ginsenoside R3 (Rg3) plays a protective role in sepsis-induced organ injuries and mitochondrial dysfunction. Long noncoding RNA (lncRNA) taurine-upregulated gene 1 (TUG1) is regarded as a regulator in sepsis. However, the association between TUG1 and Rg3 remains elusive. Methods A sepsis mouse model was established by caecal ligation and puncture (CLP), and liver injury was induced by haematoxylin-eosin (H&E) staining. Lipopolysaccharide (LPS) was used to induce hepatocyte damage. The expression levels of TUG1, microRNA (miR)-200a-3p, and silencing information regulator 1 (SIRT1) were examined by quantitative real-time polymerase chain reaction (qRT–PCR) assays. Cell viability was monitored using the Cell Counting Kit-8 (CCK-8) assay. MitoSOX Red staining and CBIC2 (JC-1) dye were employed to detect mitochondrial reactive oxygen species (ROS) and mitochondrial transmembrane potential (MTP) levels, respectively. The interaction between miR-200a-3p and TUG1 or SIRT1 was confirmed via dual-luciferase reporter or RNA immunoprecipitation (RIP) assay. Results Rg3 upregulated TUG1 expression in liver tissues of CLP mice and LPS-induced hepatocytes. Rg3 could activate autophagy to improve mitochondrial dysfunction in LPS-treated hepatocytes, which was partially reversed by TUG1 depletion or miR-200a-3p overexpression. Importantly, TUG1 targeted miR-200a-3p to activate the SIRT1/AMP-activated protein kinase (AMPK) pathway in LPS-treated hepatocytes. Moreover, gain of TUG1 ameliorated mitochondrial dysfunction in LPS-treated hepatocytes by sequestering miR-200a-3p. Conclusion Our study revealed that Rg3 increased TUG1 expression and reduced miR-200a-3p expression to stimulate the SIRT1/AMPK pathway, thereby enhancing autophagy to improve sepsis-induced liver injury and mitochondrial dysfunction.