VDR restores the expression of PINK1 and BNIP3 in TECs of streptozotocin-induced diabetic mice.

Defective mitophagy in renal tubular epithelial cells is one of the main drivers of renal fibrosis in diabetic kidney disease. Our gene sequencing data showed the expression of PINK1 and BNIP3, two key molecules of mitophagy, was decreased in renal tissues of VDR-knockout mice. Herein, streptozotocin (STZ) was used to induce renal interstitial fibrosis in mice. VDR deficiency exacerbated STZ-induced renal impairment and defective mitophagy. Paricalcitol (pari, a VDR agonist) and the tubular epithelial cell-specific overexpression of VDR restored the expression of PINK1 and BNIP3 in the renal cortex and attenuated STZ-induced kidney fibrosis and mitochondrial dysfunction. In HK-2 cells under high glucose conditions, an increased level of α-SMA, COL1, and FN and a decreased expression of PINK1 and BNIP3 with severe mitochondrial damage were observed, and these alterations could be largely reversed by pari treatment. ChIP-qPCR and luciferase reporter assays showed VDR could positively regulate the transcription of Pink1 and Bnip3 genes. These findings reveal that VDR could restore mitophagy defects and attenuate STZ-induced fibrosis in diabetic mice through regulation of PINK1 and BNIP3.

SENP1 attenuates hypoxia­reoxygenation injury in liver sinusoid endothelial cells by relying on the HIF­1α signaling pathway.

Liver sinusoidal endothelial cells (LSECs) have an important role in hepatic ischemia­reperfusion injury (I/R), but the specific molecular mechanism of action is unknown. LSEC proliferation is regulated and fenestration is maintained via the Sentrin/SUMO­specific protease 1 (SENP1)/hypoxia­inducible factor­1α (HIF­1α) signaling axis under hypoxic conditions. In the present study, a hypoxia­reoxygenation (H­R) injury model was established using mouse LSECs to explore the relationship between SENP1 and H­R injury in vitro, and the specific underlying mechanism was identified, revealing new targets for the clinical attenuation of hepatic I/R injury. Following the culture of LSECs under H­R conditions, it was demonstrated that the expression of SENP1 was upregulated by reverse transcription­quantitative polymerase chain reaction and western blotting (WB). In addition, scanning electron microscopy indicated that fenestrae damage was increased, a Cell Counting Kit­8 assay demonstrated that the proliferation of cells was impaired and flow cytometry showed that apoptosis was increased. After silencing SENP1 expression with short interfering RNA, the proliferation activity of LSECs decreased, the fenestrae damage increased, the apoptosis rate increased and the expression levels of SENP1, HIF­1α, heme oxygenase and Bcl­2 were downregulated (as demonstrated by WB), while the expression levels of apoptosis­related proteins, cleaved­caspase­3 and Bax, were upregulated. Enzyme­linked immunosorbent assay detection showed that the level of vascular endothelial growth factor in the supernatant decreased and the level of IL­6 and TNF­α increased. Following the administration of an HIF­1α signaling pathway agonist, the situation was reversed. These results therefore suggested that SENP1 attenuated the reduction in proliferation, apoptosis and fenestration of LSECs observed following H­R injury through the HIF­1α signaling pathway. In conclusion, SENP1 may attenuate H­R injury in LSECs in a HIF­1α signaling pathway­dependent manner.

VDR regulates mitochondrial function as a protective mechanism against renal tubular cell injury in diabetic rats.

PURPOSE: To investigate the regulatory effect and mechanism of Vitamin D receptor (VDR) on mitochondrial function in renal tubular epithelial cell under diabetic status. METHODS: The diabetic rats induced by streptozotocin (STZ) and HK-2 cells under high glocose(HG)/transforming growth factor beta (TGF-ß) stimulation were used in this study. Calcitriol was administered for 24 weeks. Renal tubulointerstitial injury and some parameters of mitochondrial function including mitophagy, mitochondrial fission, mitochondrial ROS, mitochondrial membrane potential (MMP), mitochondrial ATP, Complex V activity and mitochondria-associated ER membranes (MAMs) integrity were examined. Additionally, paricalcitol, 3-MA (an autophagy inhibitor), VDR over-expression plasmid, VDR siRNA and Mfn2 siRNA were applied in vitro. RESULTS: The expression of VDR, Pink1, Parkin, Fundc1, LC3II, Atg5, Mfn2, Mfn1 in renal tubular cell of diabetic rats were decreased significantly. Calcitriol treatment reduced the levels of urinary albumin, serum creatinine and attenuated renal tubulointerstitial fibrosis in STZ induced diabetic rats. In addition, VDR agonist relieved mitophagy dysfunction, MAMs integrity, and inhibited mitochondrial fission, mitochondrial ROS. Co-immunoprecipitation analysis demonstrated that VDR interacted directly with Mfn2. Mitochondrial function including mitophagy, mitochondrial membrane potential (MMP), mitochondrial Ca2+, mitochondrial ATP and Complex V activity were decreased dramatically in HK-2 cells under HG/TGF-ß ambience. In vitro pretreatment of HK-2 cells with autophagy inhibitor 3-MA, VDR siRNA or Mfn2 siRNA negated the activating effects of paricalcitol on mitochondrial function. Pricalcitol and VDR over-expression plasmid activated Mfn2 and then partially restored the MAMs integrity. Additionally, VDR restored mitophagy was partially associated with MAMs integrity through Fundc1. CONCLUSION: Activated VDR could contribute to restore mitophagy through Mfn2-MAMs-Fundc1 pathway in renal tubular cell. VDR could recover mitochondrial ATP, complex V activity and MAMs integrity, inhibit mitochondrial fission and mitochondrial ROS. It indicating that VDR agonists ameliorate renal tubulointerstitial fibrosis in diabetic rats partially via regulation of mitochondrial function.

Mitofusin2 Ameliorated Endoplasmic Reticulum Stress and Mitochondrial Reactive Oxygen Species Through Maintaining Mitochondria-Associated Endoplasmic Reticulum Membrane Integrity in Cisplatin-Induced Acute Kidney Injury.

Aims: This study investigated the regulatory effect of Mitofusin2 (Mfn2) on mitochondria-associated endoplasmic reticulum membrane (MAM) integrity and cellular injury in cisplatin-induced acute kidney injury (CP-AKI). Results: CP-AKI mice exhibited decreased expression of Mfn2, increased expression of phosphorylated adenosine monophosphate-activated protein kinase (p-AMPK), abnormal mitochondrial morphology, and reduced MAMs integrity, accompanied by the activation of mitochondrial reactive oxygen species (ROS) and endoplasmic reticulum (ER) stress (inositol-requiring enzyme 1 [IRE1] and PERK pathways). In in vitro studies, CP-induced mitochondrial ROS, ER-stress activation, and increased apoptosis were accompanied by the downregulation of Mfn2 and MAMs integrity reduction in Boston University mouse proximal tubular cells (BUMPT) and human proximal tubular epithelial cells (HK-2). Pretreatment of BUMPT cells with the Mfn2 plasmid partially restored the integrity of MAMs, negatively controlled IRE1 and PERK pathways, and inhibited cell apoptosis. In contrast, ER-stress and MAMs integrity violations were increased after Mfn2 small-interfering RNA (siRNA) treatment in HK-2 cells under CP treatment. Coimmunoprecipitation analysis demonstrated that Mfn2 interacted with PERK and IRE1. Furthermore, the adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK), acadesine (AICAR), had a similar effect to Mfn2 plasmid in the regulation of ER stress and MAMs. Conversely, the ER-stress inhibitor, 4-phenylbutyric acid (4-PBA), had no effect on the expression of Mfn2 and MAMs integrity. Innovation and Conclusion: This is the first study to explore the association between MAMs, ER stress, and Mfn2 in CP-AKI. Downregulation of Mfn2 expression abolished the MAMs integrity, and induced ER stress, mitochondrial ROS, and tubular cell apoptosis. This suggests that the Mfn2-MAMs pathway is a potential therapeutic target in CP-AKI. Antioxid. Redox Signal. 40, 16-39. The Ethical Registration number of animal experiment in this study was CSU-2022-01-0095.

Association of vitamin D metabolites with arteriovenous fistula function in hemodialysis patients: A single center study.

INTRODUCTION: Arteriovenous fistula (AVF) is a primary dialysis vascular access commonly used for maintaining hemodialysis (MHD) patients. Vitamin D (VD) is a fat-soluble steroid hormone that is closely related to vascular endothelial function. This study aimed to investigate the association between VD metabolites and AVF failure in patients undergoing HD. METHODS: This study included 443 HD patients using AVF between January 2010 and January 2020. The AVF operations in these patients were newly created by the same physician. We analyzed the AVF patency rates using the chi-square test. Univariate and multivariate logistic regression analyses were performed to explore risk factors for AVF failure. Survival analysis was performed to explore AVF survival at different serum 25-hydroxyvitamin D (25(OH)D) concentrations. RESULTS: Logistic regression analyses showed that male sex; age; BMI; serum albumin, triglyceride, phosphorus, 25(OH)D, iPTH and hemoglobin levels, history of hypertension, CHD, diabetes, stroke, and antiplatelet drug use; and smoking habits were not risk factors for AVF failure. The failure incidence rates of AVF in subjects in the VD deficiency and non VD deficiency group were not statistically significant (25.0% vs. 30.8%, p = 0.344). The AVF failure incidence rates at 1, 3, and 5 years in the patients with 25(OH)D levels more than 20 ng/mL were 26%, 29%, and 37%, respectively, and the one-year AVF failure incidence rates were 27% in the patients with 25(OH)D levels less than 20 ng/mL. In addition, the Kaplan-Meier analysis suggested that the no significant differences were noted when calculating the cumulative survival rates of AVF between the two groups within 50 months of AVF using. CONCLUSION: Our findings suggest that 25(OH)D deficiency is not associated with AVF failure incidence rates, and that 25(OH)D deficiency has no significant impact on long-term cumulative AVF survival rate.

Machine Learning-Based Prediction of Acute Kidney Injury Following Pediatric Cardiac Surgery: Model Development and Validation Study.

BACKGROUND: Cardiac surgery-associated acute kidney injury (CSA-AKI) is a major complication following pediatric cardiac surgery, which is associated with increased morbidity and mortality. The early prediction of CSA-AKI before and immediately after surgery could significantly improve the implementation of preventive and therapeutic strategies during the perioperative periods. However, there is limited clinical information on how to identify pediatric patients at high risk of CSA-AKI. OBJECTIVE: The study aims to develop and validate machine learning models to predict the development of CSA-AKI in the pediatric population. METHODS: This retrospective cohort study enrolled patients aged 1 month to 18 years who underwent cardiac surgery with cardiopulmonary bypass at 3 medical centers of Central South University in China. CSA-AKI was defined according to the 2012 Kidney Disease: Improving Global Outcomes criteria. Feature selection was applied separately to 2 data sets: the preoperative data set and the combined preoperative and intraoperative data set. Multiple machine learning algorithms were tested, including K-nearest neighbor, naive Bayes, support vector machines, random forest, extreme gradient boosting (XGBoost), and neural networks. The best performing model was identified in cross-validation by using the area under the receiver operating characteristic curve (AUROC). Model interpretations were generated using the Shapley additive explanations (SHAP) method. RESULTS: A total of 3278 patients from one of the centers were used for model derivation, while 585 patients from another 2 centers served as the external validation cohort. CSA-AKI occurred in 564 (17.2%) patients in the derivation cohort and 51 (8.7%) patients in the external validation cohort. Among the considered machine learning models, the XGBoost models achieved the best predictive performance in cross-validation. The AUROC of the XGBoost model using only the preoperative variables was 0.890 (95% CI 0.876-0.906) in the derivation cohort and 0.857 (95% CI 0.800-0.903) in the external validation cohort. When the intraoperative variables were included, the AUROC increased to 0.912 (95% CI 0.899-0.924) and 0.889 (95% CI 0.844-0.920) in the 2 cohorts, respectively. The SHAP method revealed that baseline serum creatinine level, perfusion time, body length, operation time, and intraoperative blood loss were the top 5 predictors of CSA-AKI. CONCLUSIONS: The interpretable XGBoost models provide practical tools for the early prediction of CSA-AKI, which are valuable for risk stratification and perioperative management of pediatric patients undergoing cardiac surgery.

The Effects of Indobufen on Micro-Inflammation and Peritoneal Transport Function in Patients Undergoing Continuous Ambulate Peritoneal Dialysis: A Prospective Randomized Controlled Study.

Indobufen possesses anticoagulant and antithrombotic effects that can improve micro-inflammation and renal function. This study aimed to examine whether indobufen could improve the microinflammatory state in patients on continuous ambulatory peritoneal dialysis (CAPD) and explore its therapeutic effects on peritoneal transport function. A total of 60 patients undergoing CAPD from October 2019 to October 2020 were selected and randomized to the control and indobufen groups. All patients received conventional treatments. Blood routine and the serum and peritoneal effusion levels of tumor necrosis factor-α (TNF-α), transforming growth factor-ß1 (TGF-ß1), cellular fibronectin (cFN), and vascular endothelial growth factor were determined before and after 6 months of treatment. The peritoneal equilibrium test (PET) was used to evaluate peritoneal transport function. There were no significant differences in PET results, microinflammatory state, and biochemical indices between the two groups before treatment (P > 0.05). After 6 months of treatment, platelet-to-lymphocyte ratio and serum and peritoneal effusion TNF-α levels in the indobufen group were decreased compared with the control group (P < 0.05). Serum and peritoneal effusion TGF-ß1 and cFN levels in the indobufen group were reduced compared with the control group (P < 0.05). PET results in the indobufen group were decreased compared with baseline (P < 0.05). The difference in PET results between the two groups before and after treatment was statistically significant (P < 0.05). Indobufen could improve the peritoneal transport function in patients undergoing CAPD. The underlying mechanism might be related to the improvement of the microinflammatory state and peritoneal fibrosis. SIGNIFICANCE STATEMENT: Microinflammation and peritoneal fibrosis can lead to peritoneal failure in CAPD. Indobufen is a novel antiplatelet drug that can alleviate renal fibrosis and improve renal function in patients with diabetic nephropathy. Indobufen can improve the peritoneal transport function in patients undergoing CAPD. The mechanism of indobufen improving the peritoneal function might be related to the improvement of the microinflammatory state and peritoneal fibrosis.

Piezo1 activation facilitates ovarian cancer metastasis via Hippo/YAP signaling axis.

Ovarian cancer (OC) is a highly malignant cancer with great metastatic potential. Here we aimed to investigate the role of Piezo1, a gene related to the mechanical environment of the tumor, in promoting the metastasis of OC. We performed Piezo1 knockdown in A-1847 cells using small hairpin RNAs, and the cells were inoculated subcutaneously in nude mice. Piezo1 knockdown decreased the tumor growth rate of OC tumor xenografts in mice and reduced cell migration in vitro. Metastasis in the lung was also attenuated after Piezo1 knockdown as revealed by HE staining of the lung tissues, which was concomitant with downregulation of E-Cadherin and vimentin and upregulation of N-Cadherin analyzed using western blot analysis, suggesting suppressed epithelial-to-mesenchymal transition. Migration of Piezo1-knockdown cells was also analyzed for their migratory capabilities using the scratch assay. We also analyzed the key proteins in the Hippo/YAP signaling pathway using western blot after treating A-1847 and 3AO cells with a Piezo1 inducer, Yoda1. Piezo1 inducer Yoda1 activated Hippo/YAP signal in OC cells. In conclusion, Piezo1 is overexpressed in OC tissues and contributes to OC tumor growth and metastasis. Suppression of Piezo1 is a potential therapeutic strategy for OC.

Circular RNA ERBIN Promotes Proliferation of Hepatocellular Carcinoma via the miR-1263/CDK6 Axis.

Objectives: Hepatocellular carcinoma (HCC) is the most common primary liver cancer and characterized by high aggressiveness and extremely poor prognosis. Increasing evidence has suggested that circular RNAs (circRNAs), which are highly stable, play crucial roles in the progression of multiple malignancies. However, the roles of circRNAs in HCC remain elusive. Materials and Methods: The expression patterns of circRNAs in HCC were identified by qRT-PCR. A series of functional experiments both in vivo and in vitro were used to determine the role of circERBIN in HCC proliferation. Bioinformatics and an RNA pulldown assay were used to identify potential downstream targets of circERBIN. Results: The expression of circERBIN was upregulated in HCC cell lines and tissues, which was predictive of a poor prognosis in HCC patients. Elevated circERBIN promoted G1/S transition of HCC cells, thus facilitating the proliferation and tumorigenesis of HCC cells. Mechanistic investigations revealed that circERBIN regulated HCC proliferation by acting as a sponge of miR-1263, which subsequently targeted cyclin dependent kinase 6 and controlled G1/S transition. Conclusion: Taken together, these results determined that circERBIN functions as an important epigenetic regulator in HCC development, highlighting that circERBIN is a promising target for treatment of HCC.

A positive feedback loop: RAD18-YAP-TGF-ß between triple-negative breast cancer and macrophages regulates cancer stemness and progression.

As a key regulator of the DNA translesion synthesis (TLS) pathway, RAD18 is error-prone and contributes to the accumulation of DNA mutations. Our previous study showed that it plays an essential role in the progression of multiple tumors. However, the mechanism through which RAD18 influences triple-negative breast cancer (TNBC), especially the interaction between tumor cells and the tumor microenvironment, remains elusive. In this study, we showed that RAD18 expression is markedly higher in patients with high T stage TNBC and inversely correlated with prognosis. High expression of RAD18 facilitated a highly stem-cell phenotype through the Hippo/YAP pathway, which supports the proliferation of TNBC. In addition, the cytokine byproduct TGF-ß activates macrophages to have an M2-like tumor-associated macrophage (TAM) phenotype. Reciprocally, TGF-ß from TAMs activated RAD18 in TNBC to enhance tumor stemness, forming a positive feedback loop. Inhibition of YAP or TGF-ß breaks this loop and suppresses cancer stemness and proliferation In nude mice, RAD18 promoted subcutaneous transplanted tumor growth and M2-type TAM recruitment. Collectively, the RAD18-YAP-TGF-ß loop is essential for the promotion of the stemness phenotype by TNBC and could be a potential therapeutic target for TNBC.

Vitamin D-VDR (vitamin D receptor) regulates defective autophagy in renal tubular epithelial cell in streptozotocin-induced diabetic mice via the AMPK pathway.

Diabetic nephropathy (DN) has become a major cause of end-stage renal disease, and autophagy disorder is implicated in the pathogenesis of DN. Our previous studies found that vitamin D (VD) and VDR (vitamin D receptor) played a renoprotective role by inhibiting inflammation and fibrosis. However, whether VD-VDR regulates autophagy disorders in DN remains unclear. In this study, we established a streptozotocin (STZ)-induced diabetic model in vdr knockout (vdr-KO) mice and VDR specifically overexpressed in renal proximal tubular epithelial cells (Vdr-OE) mice. Our results showed that paricalcitol (an activated vitamin D analog) or Vdr-OE could alleviate STZ-induced ALB (albumin) excretion, renal tubule injury and inflammation, while these were worsened in vdr-KO mice. Defective autophagy was observed in the kidneys of STZ mice, which was more pronounced in vdr-KO mice and could be partially restored by paricalcitol or Vdr-OE. In high glucose-induced HK-2 cells, defective autophagy and decreased PRKAA1/AMPK phosphorylation was observed, which could be partially restored by paricalcitol in a VDR-dependent manner. AMPK inhibitor abolished paricalcitol-induced autophagy activation, and AMPK activator restored the defective autophagy in high glucose-induced HK-2 cells. Furthermore, paricalcitol-mediated AMPK activation was abrogated by CAMKK2/CaMKKß inhibition, but not by STK11/LKB1 knockout. Meanwhile, paricalcitol rescued the decreased Ca2+ concentration induced by high glucose. In conclusion, VD-VDR can restore defective autophagy in the kidney of STZ-induced diabetic mice, which could be attributed to the activation of the Ca2+-CAMKK2-AMPK pathway in renal tubular epithelial cells.Abbreviations: ACTB/ß-actin: actin beta;AGE: advanced glycation end-products;AMPK: AMP-activated protein kinase;CAMKK2/CaMKKß: calcium-calmodulin dependent protein kinase kinase 2;CQ: chloroquine;DN: diabetic nephropathy;HG: high levels of glucose;KO: knockout;LG: low levels of glucose;MAP1LC3/LC3: microtubule associated protein 1 light chain 3;NOD2: nucleotide binding oligomerization domain containing 2;OE: overexpression;PAS: periodic acid Schiff; Pari: paricalcitol;PTECs: proximal renal tubule epithelial cells;RT: room temperature;SQSTM1/p62: sequestosome 1;STK11/LKB1: serine/threonine kinase 11;STZ: streptozotocin;TEM: transmission electron microscopy;VD: vitamin D;VDR: vitamin D receptor;WT: wild-type.

CircCRIM1 Promotes Hepatocellular Carcinoma Proliferation and Angiogenesis by Sponging miR-378a-3p and Regulating SKP2 Expression.

Mounting evidence has demonstrated that circular RNAs have an important function in tumorigenesis and cancer evolvement. CircCRIM1 has been shown to be a poor prognostic element in multiple human malignancies. However, the clinical significance and mechanism of circCRIM1 in hepatocellular carcinoma (HCC) is still unclear. The present study confirmed the expression level of circCRIM1 using quantitative real-time PCR. In addition, circCRIM1 siRNA and overexpression vectors were used for transfection into LM3 or Huh7 cells to down- or up-regulate the expression of circCRIM1. In vitro and in vivo experiments were performed to explore the function of circCRIM1 in HCC. RNA pull-down, RNA immunoprecipitation, fluorescent in situ hybridization, and luciferase reporter assays were conducted to confirm the relationship between miR-378a-3p and circCRIM1 or S-phase kinase-associated protein 2 (SKP2) in HCC. Then, circCRIM1 was up-regulated in HCC and its expression level was significantly associated with poor prognosis and clinicopathologic characteristics. CircCRIM1 enhanced the proliferation and angiogenesis of HCC cells in vitro and promoted xenograft growth in vivo. Moreover, circCRIM1 upregulated the expression of SKP2 by functioning as a sponge for miR-378a-3p. These findings suggest that circCRIM1 boosts the HCC progression via the miR-378-3p/SKP2 axis and may act as a crucial epigenetic therapeutic molecule target in HCC.

Hsa_circ_0011385 knockdown represses cell proliferation in hepatocellular carcinoma.

Circular RNAs (circRNAs), continuous loops of single-stranded RNA, regulate gene expression during the development of various cancers. However, the function of circRNAs in hepatocellular carcinoma (HCC) is rarely discussed. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to determine the mRNA levels of circ_0011385, miR-361-3p, and STC2 in 96 pairs of HCC tissues (tumor tissues and adjacent normal tissues), HCC cell lines, and L02 (human normal liver cell line) cells. The relationships between circ_0011385 expression and clinical features of HCC were evaluated. Functional experiments in vitro or in vivo were used to evaluate the biological function of circ_0011385. Bioinformatics analysis was performed to predict miRNAs and mRNAs sponged by circ_0011385. RNA immunoprecipitation (RIP) and dual-luciferase reporter gene assays were used to elucidate the interactions among circ_0011385, miR-361-3p, and STC2 (stanniocalcin 2). ChIP and dual-luciferase reporter gene assays were used to identify the upstream regulator of circ_0011385. High expression of circ_0011385 was observed in HCC tissues and cell lines and was significantly associated with tumor size, TNM stage, and prognosis. In addition, inhibition of circ_0011385 expression prevented the proliferation of HCC cells in vitro and in vivo. Circ_0011385 sponged miR-361-3p, thereby regulating the mRNA expression of STC2. In addition, the transcription of circ_0011385 was regulated by SP3. Circ_0011385 knockdown suppressed cell proliferation and tumor activity in HCC. Circ_0011385 may therefore serve as a new biomarker in the diagnosis and treatment of HCC.

The oncogene Mct-1 promotes progression of hepatocellular carcinoma via enhancement of Yap-mediated cell proliferation.

Malignant T-cell-amplified sequence 1 (Mct-1) has been reported as an oncogene in multiple malignant diseases. However, the function of Mct-1 in hepatocellular carcinoma (HCC) and the molecular mechanisms underlying tumor progression have not been explored. In this study, Mct-1 expression levels in HCC tissues and cells were detected by quantitative real-time PCR and western blotting. Mct-1 shRNAs and overexpression vector were transfected into HCC cells to downregulate or upregulate Mct-1 expression. In vitro and in vivo assays were performed to investigate the function of Mct-1 in cell proliferation and apoptosis. RNA sequencing analysis (RNA-seq) was performed to explore differences in gene expression when silenced Mct-1 expression. Mct-1 was upregulated in HCC specimens and cell lines, and higher expression of Mct-1 was predictive of poor survival. Overexpression of Mct-1 was shown to promote cell proliferation and repress cell apoptosis both in vitro and in vivo. The results of RNA-seq indicated that knockdown of Mct-1 suppressed Yap expression, while the results of the luciferase assay also revealed that Mct-1 increases the activity of the Yap promoter. Restoration of Yap expression in Mct-1 knockdown cells partially recovered the promotion of cell proliferation and inhibition of apoptosis. Collectively, these results indicate that Mct-1 acts as a tumor promoter gene in HCC progression by up-regulating Yap expression and, thus, could serve a novel potential diagnostic and prognostic biomarker for HCC.

Dysregulation of miR-23b-5p promotes cell proliferation via targeting FOXM1 in hepatocellular carcinoma.

Growing evidence demonstrates that MicroRNAs (miRNAs) play an essential role in contributing to tumor development and progression. However, the underlying role and mechanisms of miR-23b-5p in hepatocellular carcinoma (HCC) formation remain unclear. Our study showed that miR-23b-5p was downregulated in the HCC tissues and cell lines, and lower expression of miR-23b-5p was associated with more severe tumor size and poorer survival. Gain- or loss-of-function assays demonstrated that miR-23b-5p induced G0/G1 cell cycle arrest and inhibited cell proliferation both in vitro and in vivo. qRT-PCR, western blot and luciferase assays verified that Mammalian transcription factor Forkhead Box M1 (FOXM1), upregulated in HCC specimens, was negatively correlated with miR-23b-5p expression and acted as a direct downstream target of miR-23b-5p. In addition, miR-23b-5p could regulate cyclin D1 and c-MYC expression by directly targeting FOXM1. Further study revealed that restoration of FOXM1 neutralized the cell cycle arrest and cell proliferation inhibition caused by miR-23b-5p. Taken together, our findings suggest that miR-23b-5p acted as a tumor suppressor role in HCC progression by targeting FOXM1 and may serve as a potential novel biomarker for HCC diagnosis and prognosis.

Epigenetically modulated miR-1224 suppresses the proliferation of HCC through CREB-mediated activation of YAP signaling pathway.

Mounting evidence has demonstrated that microRNA-1224 (miR-1224) is commonly downregulated and serves as a tumor suppressor in multiple malignancies. However, the role and mechanisms responsible for miR-1224 in hepatocellular carcinoma (HCC) remain unclear. In this study, we found that the expression of miR-1224 was downregulated in HCC. Low miR-1224 expression was associated with poor clinicopathologic features and short overall survival. Moreover, the methylation status of putative CpG islands was also found to be an important part in the modulation of miR-1224 expression. miR-1224 could induce HCC cells to arrest in G0/G1 phase and inhibited the proliferation of HCC cells both in vitro and in vivo. Mechanistic investigation showed that by binding with cyclic AMP (cAMP)-response element binding protein (CREB) miR-1224 could repress the transcription and the activation of Yes-associated protein (YAP) signaling pathway. Furthermore, the expression of miR-1224 was inhibited by CREB through EZH2-mediated histone 3 lysine 27 (H3K27me3) on miR-1224 promoter, thus forming a positive feedback circuit. Our findings identify a miR-1224/CREB feedback loop for HCC progression and that blocking this circuit may represent a promising target for HCC treatment.

Hypoxia maintains the fenestration of liver sinusoidal endothelial cells and promotes their proliferation through the SENP1/HIF-1α/VEGF signaling axis.

Liver sinusoidal endothelial cells (LSECs), which play a very critical role in liver regeneration, function in hypoxic environments, but few studies have elucidated the specific mechanism. As a hypoxia-sensitive gene, Sentrin/SUMO-specific protease 1(SENP1) is upregulated in solid tumors due to hypoxia and promotes tumor proliferation. We speculate that LSECs may upregulate SENP1 in hypoxic environments and that SENP1 may act on downstream genes to allow the cells to adapt to the hypoxic environment. To elucidate the reasons for the survival of LSECs under hypoxia, we designed experiments to explore the possible mechanism. First, we cultured murine LSECs in hypoxic conditions for a certain time (24 h and 72 h), and then, we observed that the proliferation ability of the hypoxia group was higher than that of the normoxia group, and the number of unique fenestrae of the LSECs in the hypoxia group was more than that of the LSECs in the normoxia group. Then, we divided the LSECs into several groups for hypoxic culture for time points (6 h, 12 h, 24 h, 36 h, and 72 h), and we found that the expression of SENP1, HIF-1α and VEGF was significantly upregulated. Then, we silenced SENP1 and HIF-1α with si-SENP1 and si-HIF-1α, respectively. SENP1, HIF-1α and VEGF were significantly downregulated, as determined by RT-PCR, WB and ELISA. Unexpectedly, the proliferation activity of the LSECs decreased and the fenestrae disappeared more in the si-SENP1 and si-HIF-1α groups than in the control group. It is concluded that LSECs cultured under hypoxic conditions may maintain fenestrae and promote proliferation through the SENP1/HIF-1α/VEGF signaling axis, thereby adapting to the hypoxic environment.

Mitophagy: A Novel Therapeutic Target for Treating DN.

Diabetic nephropathy (DN) is a common microvascular complication of diabetes and one of the leading causes of end-stage renal disease. Tubular damage is an early change and characteristic of DN, and mitochondrial dysfunction plays an important role in the development of DN. Therefore, the timely removal of damaged mitochondria in tubular cells is an effective treatment strategy for DN. Mitophagy is a type of selective autophagy that ensures the timely elimination of damaged mitochondria to protect cells from oxidative stress. In this review, we summarize our understanding of mitochondrial dysfunction and dynamic disorders in tubular cells in DN and the molecular mechanism of mitophagy. Finally, the role of mitophagy in DN and its feasibility as a therapeutic target for DN are discussed.