Neuropilin 1 expression correlates with the Radio‐resistance of human non‐small‐cell lung cancer cells

The purpose of this study was to determine the correlation between over‐expression of the neuropilin 1 (NRP1) gene and growth, survival, and radio‐sensitivity of non‐small cell lung carcinoma (NSCLC) cells. 3‐[4,5‐dimethylthylthiazol‐2‐yl]‐2,5 diphenyltetrazolium broide (MTT) and colony assays were then performed to determine the effect of NRP1 inhibition on the in vitro growth of NSCLC cells. The Annexin V‐Fluorescein Isothiocyanate (FITC) apoptosis detection assay was performed to analyse the effect of NRP1 enhancement on apoptosis of NSCLC cells. Transwell invasion and migration assays were employed to examine the metastatic ability of A549 cells post X‐ray irradiation. In addition, Western blot assays were carried out to detect the protein level of VEGFR2, PI3K and NF‐κB. Finally, to examine the effect of shNRP1 on proliferation and radio‐sensitivity in vivo, a subcutaneous tumour formation assay in nude mice was performed. Microvessel density in tumour tissues was assessed by immunohistochemistry. The stable transfected cell line (shNRP1‐A549) showed a significant reduction in colony‐forming ability and proliferation not only in vitro, but also in vivo. Moreover, shRNA‐mediated NRP1 inhibition also significantly enhanced the radio‐sensitivity of NSCLC cells both in vitro and in vivo. The over‐expression of NRP1 was correlated with growth, survival and radio‐resistance of NSCLC cells via the VEGF‐PI3K‐ NF‐κB pathway, and NRP1 may be a molecular therapeutic target for gene therapy or radio‐sensitization of NSCLC.     

Prokineticin 1 is up‐regulated by insulin in decidualizing human endometrial stromal cells

Prokineticin 1 (PROK1), a hypoxia‐regulated angiogenic factor, has emerged as a crucial regulator of embryo implantation and placentation. Dysregulation of PROK1 has been linked to recurrent pregnancy loss, pre‐eclampsia, foetal growth restriction and preterm birth. These pregnancy complications are common in women with obesity and polycystic ovary syndrome, i.e. conditions associated with insulin resistance and compensatory hyperinsulinaemia. We investigated the effect of insulin on PROK1 expression during in vitro decidualization. Endometrial stromal cells were isolated from six healthy, regularly menstruating women and decidualized in vitro. Insulin induced a significant dose‐dependent up‐regulation of PROK1 on both mRNA and protein level in decidualizing endometrial stromal cells. This up‐regulation was mediated by hypoxia‐inducible factor 1‐alpha (HIF1α) via the phosphatidylinositol 3‐kinase (PI3K) pathway. Furthermore, we demonstrated that PROK1 did not affect the viability, but significantly inhibited the migration of endometrial stromal cells and the migratory and invasive capacity of trophoblast cell lines. This in vitro study provides new insights into the regulation of PROK1 by insulin in human decidualizing endometrial stromal cells, the action of PROK1 on migration of endometrial stromal cells, as well as migration and invasion of trophoblasts. We speculate that hyperinsulinaemia may be involved in the mechanisms by which PROK1 is linked to placenta‐related pregnancy complications.     

Involvement of intracellular caveolin‐1 distribution in the suppression of antigen‐induced mast cell activation by cationic liposomes

Cationic liposomes are commonly used as vectors to effectively introduce foreign genes into target cells. In another function, we recently showed that cationic liposomes bound to the mast cell surface suppress the degranulation induced by the cross‐linking of high‐affinity immunoglobulin E receptor in a time‐ and dose‐dependent manner. This suppression is mediated by the impairment of the sustained level of intracellular Ca²⁺ concentration ([Ca²⁺]_i) via the inhibition of store‐operated Ca²⁺ entry. Further, we revealed that the mechanism underlying an impaired [Ca²⁺]_i increase is the inhibition of the activation of the phosphatidylinositol 3‐kinase (PI3K)‐Akt pathway. Yet, how cationic liposomes inhibit the PI3K‐Akt pathway is still unclear. Here, we focused on caveolin‐1, a major component of caveolae, which is reported to be involved in the activation of the PI3K‐Akt pathway in various cell lines. In this study, we showed that caveolin‐1 translocated from the cytoplasm to the plasma membrane after the activation of mast cells and colocalized with the p85 subunit of PI3K, which seemed to be essential for PI3K activity. Meanwhile, cationic liposomes suppressed the translocation of caveolin‐1 to the plasma membrane and the colocalization of caveolin‐1 with PI3K p85 also at the plasma membrane. This finding provides new information for the development of therapies using cationic liposomes against allergies.     

HIF‐2α regulates non‐canonical glutamine metabolism via activation of PI3K/mTORC2 pathway in human pancreatic ductal adenocarcinoma

Hypoxia‐inducible factor‐2α (HIF‐2α) plays an important role in increasing cancer progression and distant metastasis in a variety of tumour types. We aimed to investigate its biological function and clinical significance in human pancreatic ductal adenocarcinoma (PDAC). A total of 283 paired PDAC tissues and adjacent normal tissues were collected from patients who underwent surgery or biopsy at Sun Yat‐sen Memorial Hospital between February 2004 and October 2016. In this study, we noted that HIF‐2α expression was significantly up‐regulated in PDAC, positively associated with disease stage, lymph‐node metastasis and patient survival, and identified as an independent prognostic factor of PDAC patients. We demonstrated that HIF‐2α silencing could reduce proliferation, migration and invasion of PDAC cells in vitro. The similar effect on growth was demonstrated in vivo. Furthermore, we noted that knock‐down of HIF‐2α significantly decreased the expression of glutamate oxaloacetate transaminase 1 (GOT1). Importantly, we confirmed that the PI3K/mTORC2 pathway promoted GOT1 expression by targeting HIF‐2α. Our study validated HIF‐2α was an important factor in PDAC progression and poor prognosis and may promote non‐canonical glutamine metabolism via activation of PI3K/mTORC2 pathway. Targeting HIF‐2α represents a novel prognostic biomarker and therapeutic target for patients with PDAC.     

Pleiotrophin,a target of miR‐384, promotes proliferation,metastasis and lipogenesis in HBV‐related hepatocellular carcinoma

Hepatitis B virus (HBV) infection plays a crucial role and is a major cause of hepatocellular carcinoma (HCC) in China. microRNAs (miRNAs) have emerged as key players in hepatic steatosis and carcinogenesis. We found that down‐regulation of miR‐384 expression was a common event in HCC, especially HBV‐related HCC. However, the possible function of miR‐384 in HBV‐related HCC remains unclear. The oncogene pleiotrophin (PTN) was a target of miR‐384. HBx inhibited miR‐384, increasing PTN expression. The PTN receptor N‐syndecan was highly expressed in HCC. PTN induced by HBx acted as a growth factor via N‐syndecan on hepatocytes and further promoted cell proliferation, metastasis and lipogenesis. PTN up‐regulated sterol regulatory element‐binding protein 1c (SREBP‐1c) through the N‐syndecan/PI3K/Akt/mTORC1 pathway and the expression of lipogenic genes, including fatty acid synthesis (FAS). PTN‐mediated de novo lipid synthesis played an important role in HCC proliferation and metastasis. PI3K/AKT and an mTORC1 inhibitor diminished PTN‐induced proliferation, metastasis and lipogenesis. Taken together, these data strongly suggest that the dysregulation of miR‐384 could play a crucial role in HBV related to HCC, and the target gene of miR‐384, PTN, represents a new potential therapeutic target for the prevention of hepatic steatosis and further progression to HCC after chronic HBV infection.     

Inhibition of Orai1‐mediated Ca2+ entry enhances chemosensitivity of HepG2 hepatocarcinoma cells to 5‐fluorouracil

Increasing evidence supports that activation of store‐operated Ca²⁺ entry (SOCE) is implicated in the chemoresistance of cancer cells subjected to chemotherapy. However, the molecular mechanisms underlying chemoresistance are not well understood. In this study, we aim to investigate whether 5‐FU induces hepatocarcinoma cell death through regulating Ca²⁺‐dependent autophagy. [Ca²⁺]_i was measured using fura2/AM dye. Protein expression was determined by Western blotting and immunohistochemistry. We found that 5‐fluorouracil (5‐FU) induced autophagic cell death in HepG2 hepatocarcinoma cells by inhibiting PI3K/AKT/mTOR pathway. Orai1 expression was obviously elevated in hepatocarcinoma tissues. 5‐FU treatment decreased SOCE and Orai1 expressions, but had no effects on Stim1 and TRPC1 expressions. Knockdown of Orai1 or pharmacological inhibition of SOCE enhanced 5‐FU‐induced inhibition of PI3K/AKT/mTOR pathway and potentiated 5‐FU‐activated autophagic cell death. On the contrary, ectopic overexpression of Orai1 antagonizes 5‐FU‐induced autophagy and cell death. Our findings provide convincing evidence to show that Orai1 expression is increased in hepatocarcinoma tissues. 5‐FU can induce autophagic cell death in HepG2 hepatocarcinoma cells through inhibition of SOCE via decreasing Orai1 expression. These findings suggest that Orai1 expression is a predictor of 5‐FU sensitivity for hepatocarcinoma treatment and blockade of Orai1‐mediated Ca²⁺ entry may be a promising strategy to sensitize hepatocarcinoma cells to 5‐FU treatment.     

Iron chelation and 2‐oxoglutarate‐dependent dioxygenase inhibition suppress mantle cell lymphoma's cyclin D1

The patients with mantle cell lymphoma (MCL) have translocation t(11;14) associated with cyclin D1 overexpression. We observed that iron (an essential cofactor of dioxygenases including prolyl hydroxylases [PHDs]) depletion by deferoxamine blocked MCL cells’ proliferation, increased expression of DNA damage marker γH2AX, induced cell cycle arrest and decreased cyclin D1 level. Treatment of MCL cell lines with dimethyloxalylglycine, which blocks dioxygenases involving PHDs by competing with their substrate 2‐oxoglutarate, leads to their decreased proliferation and the decrease of cyclin D1 level. We then postulated that loss of EGLN2/PHD1 in MCL cells may lead to down‐regulation of cyclin D1 by blocking the degradation of FOXO3A, a cyclin D1 suppressor. However, the CRISPR/Cas9‐based loss‐of‐function of EGLN2/PHD1 did not affect cyclin D1 expression and the loss of FOXO3A did not restore cyclin D1 levels after iron chelation. These data suggest that expression of cyclin D1 in MCL is not controlled by ENGL2/PHD1‐FOXO3A pathway and that chelation‐ and 2‐oxoglutarate competition‐mediated down‐regulation of cyclin D1 in MCL cells is driven by yet unknown mechanism involving iron‐ and 2‐oxoglutarate‐dependent dioxygenases other than PHD1. These data support further exploration of the use of iron chelation and 2‐oxoglutarate‐dependent dioxygenase inhibitors as a novel therapy of MCL.     

PIK3CA‐mutated melanoma cells rely on cooperative signaling through mTORC1/2 for sustained proliferation

Malignant conversion of BRAF‐ or NRAS‐mutated melanocytes into melanoma cells can be promoted by PI3′‐lipid signaling. However, the mechanism by which PI3′‐lipid signaling cooperates with mutationally activated BRAF or NRAS has not been adequately explored. Using human NRAS‐ or BRAF‐mutated melanoma cells that co‐express mutationally activated PIK3CA, we explored the contribution of PI3′‐lipid signaling to cell proliferation. Despite mutational activation of PIK3CA, melanoma cells were more sensitive to the biochemical and antiproliferative effects of broader spectrum PI3K inhibitors than to an α‐selective PI3K inhibitor. Combined pharmacological inhibition of MEK1/2 and PI3K signaling elicited more potent antiproliferative effects and greater inhibition of the cell division cycle compared to single‐agent inhibition of either pathway alone. Analysis of signaling downstream of MEK1/2 or PI3K revealed that these pathways cooperate to regulate cell proliferation through mTORC1‐mediated effects on ribosomal protein S6 and 4E‐BP1 phosphorylation in an AKT‐dependent manner. Although PI3K inhibition resulted in cytostatic effects on xenografted NRAS^Q61H/PIK3CA^H1047R melanoma, combined inhibition of MEK1/2 plus PI3K elicited significant melanoma regression. This study provides insights as to how mutationally activated PIK3CA acts in concert with MEK1/2 signaling to cooperatively regulate mTORC1/2 to sustain PIK3CA‐mutated melanoma proliferation.     

Cell entry of bovine ephemeral fever virus requires activation of Src‐JNK‐AP1 and PI3K‐Akt‐NF‐κB pathways as well as Cox‐2‐mediated PGE2/EP receptor signalling to enhance clathrin‐mediated virus endocytosis

Although we have previously demonstrated that cell entry of bovine ephemeral fever virus (BEFV) follows a clathrin‐mediated and dynamin 2‐dependent endocytosis pathway, the cellular mechanism mediating virus entry remains unknown. Here, we report that BEFV triggers simultaneously Src‐JNK‐AP1 and PI3K‐Akt‐NF‐κB signalling pathways in the stage of virus binding to induce clathrin and dynamin 2 expressions, while vesicular stomatitis virus only activates Src‐JNK signalling to enhance its entry. Activation of these pathways by ultraviolet‐inactivated BEFV suggests a role for virus binding but not viral internalization and gene expression. By blocking these signalling pathways with specific inhibitors, BEFV‐induced expressions of clathrin and dynamin 2 were significantly diminished. By labelling BEFV with 3,3′‐dilinoleyloxacarbocyanine perchlorate to track viral entry, we found that virus entry was hindered by both Src and Akt inhibitors, suggesting that these signalling pathways are crucial for efficient virus entry. In addition, BEFV also triggers Cox‐2‐catalysed prostaglandin E₂ (PGE₂) synthesis and induces expressions of G‐protein‐coupled E‐prostanoid (EP) receptors 2 and 4, leading to amplify signal cascades of Src‐JNK‐AP1 and PI3K‐Akt‐NF‐κB, which elevates both clathrin and dynamin 2 expressions. Furthermore, pretreatment of cells with adenylate cyclase (cAMP) inhibitor SQ22536 reduced BEFV‐induced Src phosphorylation as well as clathrin and dynamin 2 expressions. Our findings reveal for the first time that BEFV activates the Cox‐2‐mediated PGE₂/EP receptor signalling pathways, further enhancing Src‐JNK‐AP1 in a cAMP‐dependent manner and PI3K‐Akt‐NF‐κB in a cAMP‐independent manner. Accordingly, BEFV stimulates PGE₂/EP receptor signalling amplifying Src‐JNK‐AP1 and PI3K‐Akt‐NF‐κB pathways in an autocrine or paracrine fashion to enhance virus entry.     

Bone marrow‐derived mesenchymal stem cells enhance autophagy via PI3K/AKT signalling to reduce the severity of ischaemia/reperfusion‐induced lung injury

Autophagy, a type II programmed cell death, is essential for cell survival under stress, e.g. lung injury, and bone marrow‐derived mesenchymal stem cells (BM‐MSCs) have great potential for cell therapy. However, the mechanisms underlying the BM‐MSC activation of autophagy to provide a therapeutic effect in ischaemia/reperfusion‐induced lung injury (IRI) remain unclear. Thus, we investigate the activation of autophagy in IRI following transplantation with BM‐MSCs. Seventy mice were pre‐treated with BM‐MSCs before they underwent lung IRI surgery in vivo. Human pulmonary micro‐vascular endothelial cells (HPMVECs) were pre‐conditioned with BM‐MSCs by oxygen‐glucose deprivation/reoxygenation (OGD) in vitro. Expression markers for autophagy and the phosphoinositide 3‐kinase/protein kinase B (PI3K/Akt) signalling pathway were analysed. In IRI‐treated mice, administration of BM‐MSCs significantly attenuated lung injury and inflammation, and increased the level of autophagy. In OGD‐treated HPMVECs, co‐culture with BM‐MSCs attenuated endothelial permeability by decreasing the level of cell death and enhanced autophagic activation. Moreover, administration of BM‐MSCs decreased the level of PI3K class I and p‐Akt while the expression of PI3K class III was increased. Finally, BM‐MSCs‐induced autophagic activity was prevented using the inhibitor LY294002. Administration of BM‐MSCs attenuated lung injury by improving the autophagy level via the PI3K/Akt signalling pathway. These findings provide further understanding of the mechanisms related to BM‐MSCs and will help to develop new cell‐based therapeutic strategies in lung injury.     

Salidroside suppressing LPS‐induced myocardial injury by inhibiting ROS‐mediated PI3K/Akt/mTOR pathway in vitro and in vivo

The purpose of the present study was to investigate the effect of salidroside (Sal) on myocardial injury in lipopolysaccharide (LPS)‐induced endotoxemic in vitro and in vivo. SD rats were randomly divided into five groups: control group, LPS group (15 mg/kg), LPS plus dexamethasone (2 mg/kg), LPS plus Sal groups with different Sal doses (20, 40 mg/kg). Hemodynamic measurement and haematoxylin and eosin staining were performed. Serum levels of creatine kinase (CK), lactate dehydrogenase, the activities of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH‐px), glutathione, tumour necrosis factor‐α (TNF‐α), interleukin‐6 (IL‐6), and interleukin‐1β (IL‐1β) were measured after the rats were killed. iNOS, COX‐2, NF‐κB and PI3K/Akt/mTOR pathway proteins were detected by Western blot. In vitro, we evaluated the protective effect of Sal on rat embryonic heart‐derived myogenic cell line H9c2 induced by LPS. Reactive oxygen species (ROS) in H9c2 cells was measured by flow cytometry, and the activities of the antioxidant enzymes CAT, SOD, GSH‐px, glutathione‐S‐transferase, TNF‐α, IL‐6 and IL‐1β in cellular supernatant were measured. PI3K/Akt/mTOR signalling was examined by Western blot. As a result, Sal significantly attenuated the above indices. In addition, Sal exerts pronounced cardioprotective effect in rats subjected to LPS possibly through inhibiting the iNOS, COX‐2, NF‐κB and PI3K/Akt/mTOR pathway in vivo. Furthermore, the pharmacological effect of Sal associated with the ROS‐mediated PI3K/Akt/mTOR pathway was proved by the use of ROS scavenger, N‐acetyl‐l ‐cysteine, in LPS‐stimulated H9C2 cells. Our results indicated that Sal could be a potential therapeutic agent for the treatment of cardiovascular disease.     

Sodium 5,6‐benzylidene‐L‐ascorbate induces oxidative stress,autophagy, and growth arrest in human colon cancer HT‐29 cells

Our previous studies have demonstrated the oxidative stress properties of sodium ascorbate (SAA) and its benzaldehyde derivative (SBA) on cancer cell lines, but the molecular mechanisms mediating their cytotoxicity remain unclear. In this study, we treated human colon cancer HT‐29 cells with SAA and SBA, and found a significant exposure time‐dependent increase of cytotoxicity in both treatments, with a higher cytotoxicity for 24 h with SAA (IC₅₀ = 5 mM) than SBA (IC₅₀ = 10 mM). A short‐term treatment of cells with 10 mM SAA for 2 h revealed a destabilization of the lysosomes and subsequent induction of cell death, whereas 10 mM SBA triggered a remarkable production of reactive oxidative species, phosphorylation of survival kinase AKT, expression of cyclin kinase‐dependent inhibitor p21, and induction of transient growth arrest. The crucial role of p21 mediating this cytotoxicity was confirmed by isogenic derivatives of the human colon carcinoma HCT116 cell lines (p21^+/+ and p21^?/?), and immunoprecipitation studies with p21 antibody. The SAA cytotoxicity was blocked by co‐incubation with catalase, whereas the SBA cytotoxicity and its subsequent growth arrest were abolished by N‐acetyl‐L‐cysteine (NAC), but was not affected by PI3K phosphorylation inhibitor LY294002, or catalase, suggesting two separated oxidative stress pathways were mediated by these two ascorbates. In addition, neither active caspase 3 nor apoptotic bodies but autophagic vacuoles associated with increased LC3‐II were found in SBA‐treated HT‐29 cells; implicating that SBA induced AKT phosphorylation‐autophagy and p21‐growth arrest in colon cancer HT‐29 cells through an NAC‐inhibitable oxidative stress pathway. J. Cell. Biochem. 111: 412–424, 2010. © 2010 Wiley‐Liss, Inc.     

RAC1mutation is not a predictive biomarker for PI3’‐kinase‐β‐selective pathway‐targeted therapy

Mutational activation of RAC1 is detected in ~7% of cutaneous melanoma, with the most frequent mutation (RAC1^C85T) encoding for RAC1^P29S. RAC1^P29S is a fast‐cycling GTPase that leads to accumulation of RAC1^P29S‐GTP, which has potentially pleiotropic regulatory functions in melanoma cell signaling and biology. However, the precise mechanism by which mutationally activated RAC1^P29S propagates its pro‐tumorigenic effects remains unclear. RAC1‐GTP is reported to activate the beta isoform of PI3’‐kinase (PIK3CB/PI3Kβ) leading to downstream activation of PI3’‐lipid signaling. Hence, we employed both genetic and isoform‐selective pharmacological inhibitors to test if RAC1^P29S propagates its oncogenic signaling in melanoma through PI3Kβ. We observed that RAC1^P29S‐expressing melanoma cells were largely insensitive to inhibitors of PI3Kβ. Furthermore, RAC1^P29S melanoma cell lines showed variable sensitivity to pan‐class 1 (α/β/γ/δ) PI3’‐kinase inhibitors, suggesting that RAC1‐mutated melanoma cells may not rely on PI3’‐lipid signaling for their proliferation. Lastly, we observed that RAC1^P29S‐expressing cell lines also showed variable sensitivity to pharmacological inhibition of the RAC1 → PAK1 signaling pathway, questioning the relevance of inhibitors of this pathway for the treatment of patients with RAC1‐mutated melanoma.     

CFTR promotes malignant glioma development via up‐regulation of Akt/Bcl2‐mediated anti‐apoptosis pathway

Cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP‐activated Cl^‐ channel, is extensively expressed in the epithelial cells of various tissues and organs. Accumulating evidence indicates that aberrant expression or mutation of CFTR is related to carcinoma development. Malignant gliomas are the most common and aggressive intracranial tumours; however, the role of CFTR in the development of malignant gliomas is unclear. Here, we report that CFTR is expressed in malignant glioma cell lines. Suppression of CFTR channel function or knockdown of CFTR suppresses glioma cell viability whereas overexpression of CFTR promotes it. Additionally, overexpression of CFTR suppresses apoptosis and promotes glioma progression in both subcutaneous and orthotopic xenograft models. Cystic fibrosis transmembrane conductance regulator activates Akt/Bcl2 pathway, and suppression of PI3K/Akt pathway abolishes CFTR overexpression–induced up‐regulation of Bcl2 (MK‐2206 and LY294002) and cell viability (MK‐2206). More importantly, the protein expression level of CFTR is significantly increased in glioblastoma patient samples. Altogether, our study has revealed a mechanism by which CFTR promotes glioma progression via up‐regulation of Akt/Bcl2‐mediated anti‐apoptotic pathway, which warrants future studies into the potential of using CFTR as a therapeutic target for glioma treatment.     

Rapamycin treatment dose‐dependently improves the cystic kidney in a new ADPKD mouse model via the mTORC1 and cell‐cycle‐associated CDK1/cyclin axis

Although translational research into autosomal dominant polycystic kidney disease (ADPKD) and its pathogenesis has made considerable progress, there is presently lack of standardized animal model for preclinical trials. In this study, we developed an orthologous mouse model of human ADPKD by cross‐mating Pkd2 conditional‐knockout mice (Pkd2^f3) to Cre transgenic mice in which Cre is driven by a spectrum of kidney‐related promoters. By systematically characterizing the mouse model, we found that Pkd2^f3/f3 mice with a Cre transgene driven by the mouse villin‐1 promoter (Vil‐Cre;Pkd2^f3/f3) develop overt cysts in the kidney, liver and pancreas and die of end‐stage renal disease (ESRD) at 4–6 months of age. To determine whether these Vil‐Cre;Pkd2^f3/f3 mice were suitable for preclinical trials, we treated the mice with the high‐dose mammalian target of rapamycin (mTOR) inhibitor rapamycin. High‐dose rapamycin significantly increased the lifespan, lowered the cystic index and kidney/body weight ratio and improved renal function in Vil‐Cre;Pkd2^f3/f3 mice in a time‐ and dose‐dependent manner. In addition, we further found that rapamycin arrested aberrant epithelial‐cell proliferation in the ADPKD kidney by down‐regulating the cell‐cycle‐associated cyclin‐dependent kinase 1 (CDK1) and cyclins, namely cyclin A, cyclin B, cyclin D1 and cyclin E, demonstrating a direct link between mTOR signalling changes and the polycystin‐2 dysfunction in cystogenesis. Our newly developed ADPKD model provides a practical platform for translating in vivo preclinical results into ADPKD therapies. The newly defined molecular mechanism by which rapamycin suppresses proliferation via inhibiting abnormally elevated CDK1 and cyclins offers clues to new molecular targets for ADPKD treatment.     

LncRNA‐SULT1C2A regulates Foxo4 in congenital scoliosis by targeting rno‐miR‐466c‐5p through PI3K‐ATK signalling

Congenital scoliosis (CS) is the result of anomalous vertebrae development, but the pathogenesis of CS remains unclear. Long non‐coding RNAs (lncRNAs) have been implicated in embryo development, but their role in CS remains unknown. In this study, we investigated the role and mechanisms of a specific lncRNA, SULT1C2A, in somitogenesis in a rat model of vitamin A deficiency (VAD)‐induced CS. Bioinformatics analysis and quantitative real‐time PCR (qRT‐PCR) indicated that SULT1C2A expression was down‐regulated in VAD group, accompanied by increased expression of rno‐miR‐466c‐5p but decreased expression of Foxo4 and somitogenesis‐related genes such as Pax1, Nkx3‐2 and Sox9 on gestational day (GD) 9. Luciferase reporter and small interfering RNA (siRNA) assays showed that SULT1C2A functioned as a competing endogenous RNA to inhibit rno‐miR‐466c‐5p expression by direct binding, and rno‐miR‐466c‐5p inhibited Foxo4 expression by binding to its 3′ untranslated region (UTR). The spatiotemporal expression of SULT1C2A, rno‐miR‐466c‐5p and Foxo4 axis was dynamically altered on GDs 3, 8, 11, 15 and 21 as detected by qRT‐PCR and northern blot analyses, with parallel changes in Protein kinase B (AKT) phosphorylation and PI3K expression. Taken together, our findings indicate that SULT1C2A enhanced Foxo4 expression by negatively modulating rno‐miR‐466c‐5p expression via the PI3K‐ATK signalling pathway in the rat model of VAD‐CS. Thus, SULT1C2A may be a potential target for treating CS.     

Up‐regulated basigin‐2 in microglia induced by hypoxia promotes retinal angiogenesis

Retinal microglia cells contribute to vascular angiogenesis and vasculopathy induced by relative hypoxia. However, its concrete molecular mechanisms in shaping retinal angiogenesis have not been elucidated. Basigin, being involved in tumour neovasculogenesis, is explored to exert positive effects on retinal angiogenesis induced by microglia. Therefore, we set out to investigate the expression of basigin using a well‐characterized mouse model of oxygen‐induced retinopathy, which recapitulated hypoxia‐induced aberrant neovessel growth. Our results elucidate that basigin is overexpressed in microglia, which accumulating in retinal angiogenic sprouts. In vitro, conditioned media from microglia BV2 under hypoxia treatment increase migration and tube formation of retinal capillary endothelia cells, compared with media from normoxic condition. The angiogenic capacity of BV2 is inhibited after basigin knockdown by small interfering RNAs. A new molecular mechanism for high angiogenic capacity, whereby microglia cells release basigin via up‐regulation of PI3K‐AKT and IGF‐1 pathway to induce angiogenesis is unveiled. Collectively, our results demonstrate that basigin from hypoxic microglia plays a pivotal pro‐angiogenic role, providing new insights into microglia‐promoting retinal angiogenesis.