PPP1R81 correlates with the survival and cell proliferation in lower-grade glioma.

BACKGROUND: The specific functions of PPP1R81 has been elucidated in multiple cancers; however, its role in lower-grade glioma (LGG) remains unknown. In this research, we inspected the specific role of PPP1R81 in LGG. METHODS: We totally evaluated the expression pattern and prognostic role of PPP1R81 in multitudinous tumors. Subsequently, we systematically examined the connection between PPP1R81 expression and prognosis, clinical characteristics, biological functions, genetic variations, and immunological characteristics in LGG according to the Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Altas (CGGA) databases. In vitro experiments were executed to inspect the expression level and specific roles of PPP1R81 in LGG. RESULTS: PPP1R81 was elevated in multiple tumors and was tightly linked to a poor prognosis. LGG with higher expression of PPP1R81 showed poorer prognosis compared with lower expression of PPP1R81. The results of univariate and multivariate Cox regression analyses confirmed that the expression of PPP1R81 was an independent prognostic biomarker of LGG. Immune cell infiltration, immune checkpoint genes (ICPGs), copy number alterations (CNA), and tumor mutation burden (TMB) were also closely associated with PPP1R81 expression in LGG. In vitro experiments demonstrated that PPP1R81 was up-regulated and closely interrelated with cell proliferation and cell cycle in LGG. CONCLUSION: PPP1R81 was an independent prognostic signature and underlying therapeutic target for patients with LGG.

N6-methyladenosine (m6A)-connected lncRNAs are linked to survival and immune infiltration in glioma patients.

BACKGROUND: The connection between m6A-assiociateed lncRNAs and prognosis has been demonstrated in multiple types of tumors. However, potential roles of m6A-assiociateed lncRNAs in glioma is still rare. METHODS: We implemented consensus cluster analysis to group the downloaded samples into two subtypes. The least absolute shrinkage and selection operator (LASSO) analysis was used to create a risk model. Additionally, the conjunction between m6A-related lncRNAs and immune cells infiltration was explored by conducting the R package. Ultimately, we inspected the underlying downstream pathways of the two subtypes by performing Gene Set Enrichment Analysis (GSEA). The expression level of m6A-connected lncRNAs in glioma were examined by conducting in vitro experiments. RESULTS: We ascertained two subtypes of glioma in line with the consensus clustering of m6A-associated lncRNAs. We confirmed that age, grade, and IDH are related to the two subtypes. Additionally, the immune cells infiltration and immune checkpoint molecules of the two clusters were discussed. A risk signature including AL359643.3, AL445524.1, AL162231.2, AL117332.1, AP001486.2, POLR2J4, AC120036.4, LINC00641, LINC00900, CRNDE, and AL158212.3, was identified using the Cox regression and LASSO analyses. We also verified the prognostic value and discussed the immune cells infiltration and immune checkpoint molecules of the risk signature. In vitro experiments verified that the m6A-associated lncRNAs was abnormally expressed in glioma. CONCLUSION: We elaborated the significant role of m6A-connected lncRNAs in glioma prognosis and immune infiltration and suggest that these key regulators may serve as underlying therapeutic targets to build up the efficacy of glioma immunotherapy.

Small extracellular vesicles secreted by induced pluripotent stem cell-derived mesenchymal stem cells improve postoperative cognitive dysfunction in mice with diabetes.

Postoperative cognitive dysfunction (POCD) is a common surgical complication. Diabetes mellitus (DM) increases risk of developing POCD after surgery. DM patients with POCD seriously threaten the quality of patients' life, however, the intrinsic mechanism is unclear, and the effective treatment is deficiency. Previous studies have demonstrated neuronal loss and reduced neurogenesis in the hippocampus in mouse models of POCD. In this study, we constructed a mouse model of DM by intraperitoneal injection of streptozotocin, and then induced postoperative cognitive dysfunction by transient bilateral common carotid artery occlusion. We found that mouse models of DM-POCD exhibited the most serious cognitive impairment, as well as the most hippocampal neural stem cells (H-NSCs) loss and neurogenesis decline. Subsequently, we hypothesized that small extracellular vesicles secreted by induced pluripotent stem cell-derived mesenchymal stem cells (iMSC-sEVs) might promote neurogenesis and restore cognitive function in patients with DM-POCD. iMSC-sEVs were administered via the tail vein beginning on day 2 after surgery, and then once every 3 days for 1 month thereafter. Our results showed that iMSC-sEVs treatment significantly recovered compromised proliferation and neuronal-differentiation capacity in H-NSCs, and reversed cognitive impairment in mouse models of DM-POCD. Furthermore, miRNA sequencing and qPCR showed miR-21-5p and miR-486-5p were the highest expression in iMSC-sEVs. We found iMSC-sEVs mainly transferred miR-21-5p and miR-486-5p to promote H-NSCs proliferation and neurogenesis. As miR-21-5p was demonstrated to directly targete Epha4 and CDKN2C, while miR-486-5p can inhibit FoxO1 in NSCs. We then demonstrated iMSC-sEVs can transfer miR-21-5p and miR-486-5p to inhibit EphA4, CDKN2C, and FoxO1 expression in H-NSCs. Collectively, these results indicate significant H-NSC loss and neurogenesis reduction lead to DM-POCD, the application of iMSC-sEVs may represent a novel cell-free therapeutic tool for diabetic patients with postoperative cognitive dysfunction.

Glioma cells enhance angiogenesis and inhibit endothelial cell apoptosis through the release of exosomes that contain long non-coding RNA CCAT2.

Angiogenesis is a key event in the progression of gliomas. Exosomes, as signaling extracellular organelles, modulate the tumor microenvironment and promote angiogenesis and tumor progression. We previously demonstrated that long intergenic non-coding RNA CCAT2 (linc-CCAT2) was overexpressed in glioma tissues and functioned to promote glioma progression. Therefore, this study aimed to explore an underlying mechanism of glioma cell-affected angiogenesis. First, qRT-PCR was used to determine the expression level of linc-CCAT2 in 4 glioma cell lines and 293T cells, and the results revealed that the U87-MG cells exhibited the highest expression level. Subsequently, the pro-angiogenesis function of exosomes that were derived from negative control shRNA-treated U87-MG cells (ncU87-Exo) and linc-CCAT2 shRNA-treated U87-MG cells (shU87-Exo) was evaluated in vitro and in vivo. We found that ncU87-Exo, which was enriched in linc-CCAT2, could be taken up by HUVECs. ncU87-Exo improved the linc-CCAT2 expression level in HUVECs and more strongly promoted HUVEC migration, proliferation, tubular-like structure formation in vitro and arteriole formation in vivo as well as inhibited HUVEC apoptosis induced by hypoxia. Further mechanistic studies revealed that ncU87-Exo could upregulate VEGFA and TGFß expression in HUVECs as well as promote Bcl-2 expression and inhibit Bax and caspase-3 expression. Finally, gain-/loss-of-function studies revealed that the overexpression of linc-CCAT2 in HUVECs activated VEGFA and TGFß, promoted angiogenesis, promoted Bcl-2 expression and inhibited Bax and caspase-3 expression, thus decreasing apoptosis. Downregulation of linc-CCAT2 revealed the opposite effect. Thus, our results revealed a new exosome­mediated mechanism by which glioma cells could promote angiogenesis through the transfer of linc-CCAT2 by exosomes to endothelial cells. Moreover, we suggest that exosomes and linc-CCAT2 are putative therapeutic targets in glioma.

A risk score based on admission characteristics to predict progressive hemorrhagic injury from traumatic brain injury in children.

Traumatic brain injury (TBI) is one of the leading causes of death and disability in children, and progressive hemorrhagic injury (PHI) post TBI is associated with poor outcomes. Therefore, the objective of this study was to develop and validate a prognostic model that uses the information available at admission to determine the likelihood of PHI occurrence after TBI in children. The identified demographic data, cause of injury, clinical predictors on admission, computed tomography scan characteristics, and routine laboratory parameters were collected and used to develop a PHI prognostic model with logistic regression analysis, and the prediction model was validated in 68 children. Eight independent prognostic factors were identified: lower Glasgow coma scale score (3 ~ 8) (6 points), intra-axial bleeding/brain contusion (4 points), midline shift ≥5 mm (9 points), platelets <100 × 109/L (11 points), prothrombin time >14 s (6 points), international normalized ratio >1.25 (7 points), D-dimer ≥5 mg/L (14 points), and glucose ≧10 mmol/L (11 points). We calculated risk scores for each child and defined three risk groups: low risk (0-16 points), intermediate risk (17-36 points), and high risk (37-68 points). In the development cohort, the PHI rates after TBI for the low-, intermediate-, and high-risk groups were 10.1, 47.9, and 84.2%, respectively. In the validation cohort, the corresponding PHI rates were 10.9, 47.5, and 85.4%, respectively. The C-statistic for the point system was 0.873 (p = 0.586 by the Hosmer-Lemeshow test) in the development cohort and 0.877 (p = 0.524 by the Hosmer-Lemeshow test) in the validation cohort. CONCLUSION: Using admission predictors, we developed a relatively simple risk score that accurately predicted the risk of PHI after TBI in children. What is Known: • TBI is one of the leading causes of death and disability in children, and PHI post TBI is associated with poor outcomes. •Prediction of patients at low risk of PHI could help reduce treatment costs, whereas identification of patients at high risk of PHI could direct early medical intervention to improve outcomes. What is New: • This study firstly developed a risk score system by assessing the admission information that could provide an earlier prediction of the occurrence of PHI after acute TBI in children.

Knockdown of linc-OIP5 inhibits proliferation and migration of glioma cells through down-regulation of YAP-NOTCH signaling pathway.

Long intergenic noncoding RNAs (lincRNAs) play important roles in regulating the biological functions and underlying molecular mechanisms of glioma. Here, we investigated the expression level and biological function of linc-OIP5 in glioma. In the current study, we used quantitative real-time polymerase chain reaction (qRT-PCR) to determine the expression of linc-OIP5 in glioma tissues and in adjacent normal tissues. Level of linc-OIP5 was up-regulated in glioma tissues and significantly correlated with the advanced tumor stage (III/IV). Subsequently, the efficacy of knockdown of linc-OIP5 by linc-OIP5-small interfering RNA (siRNA) was evaluated in vitro, and we found that knockdown of linc-OIP5 can inhibit glioma cells proliferation, migration in vitro and tumor formation in vivo. Further mechanistic studies revealed the effect of linc-OIP5 knockdown on glioma cell phenotype at least partially through down-regulation of YAP and inhibition of Notch signaling pathway activity. Thus, our study provides evidence that linc-OIP5 is a potential therapeutic target and novel molecular biomarker for glioma.

Role of Phosphorylated HDAC4 in Stroke-Induced Angiogenesis.

Acetylation or deacetylation of chromatin proteins and transcription factors is part of a complex signaling system that is involved in the control of neurological disorders. Recent studies have demonstrated that histone deacetylases (HDACs) exert protective effects in attenuating neuronal injury after ischemic insults. Class IIa HDAC4 is highly expressed in the brain, and neuronal activity depends on the nucleocytoplasmic shuttling of HDAC4. However, little is known about HDAC4 and its roles in ischemic stroke. In this study, we report that phosphorylation of HDAC4 was remarkably upregulated after stroke and blockade of HDAC4 phosphorylation with GÖ6976 repressed stroke-induced angiogenesis. Phosphorylation of HDAC4 was also increased in endothelial cells hypoxia model and suppression of HDAC4 phosphorylation inhibited the tube formation and migration of endothelial cells in vitro. Furthermore, in addition to the inhibition of angiogenesis, blockade of HDAC4 phosphorylation suppressed the expression of genes downstream of HIF-VEGF signaling in vitro and in vivo. These data indicate that phosphorylated HDAC4 may serve as an important regulator in stroke-induced angiogenesis. The protective mechanism of phosphorylated HDAC4 is associated with HIF-VEGF signaling, implicating a novel therapeutic target in stroke.

tRNA-Derived Small Non-Coding RNAs in Response to Ischemia Inhibit Angiogenesis.

Ischemic injuries will lead to necrotic tissue damage, and post-ischemia angiogenesis plays critical roles in blood flow restoration and tissue recovery. Recently, several types of small RNAs have been reported to be involved in this process. In this study, we first generated a rat brain ischemic model to investigate the involvement of new types of small RNAs in ischemia. We utilized deep sequencing and bioinformatics analyses to demonstrate that the level of small RNA fragments derived from tRNAs strikingly increased in the ischemic rat brain. Among these sequences, tRNA(Val)- and tRNA(Gly)-derived small RNAs account for the most abundant segments. The up-regulation of tRNA(Val)- and tRNA(Gly)-derived fragments was verified through northern blot and quantitative PCR analyses. The levels of these two fragments also increased in a mouse hindlimb ischemia model and cellular hypoxia model. Importantly, up-regulation of the tRNA(Val)- and tRNA(Gly)-derived fragments in endothelial cells inhibited cell proliferation, migration and tube formation. Furthermore, we showed that these small RNAs are generated by angiogenin cleavage. Our results indicate that tRNA-derived fragments are involved in tissue ischemia, and we demonstrate for the first time that tRNA(Val)- and tRNA(Gly)-derived fragments inhibit angiogenesis by modulating the function of endothelial cells.

Iron-Doped Carbon Nitride-Type Polymers as Homogeneous Organocatalysts for Visible Light-Driven Hydrogen Evolution.

Graphitic carbon nitrides have appeared as a new type of photocatalyst for water splitting, but their broader and more practical applications are oftentimes hindered by the insolubility or difficult dispersion of the material in solvents. We herein prepared novel two-dimensional (2D) carbon nitride-type polymers doped by iron under a mild one-pot method through preorganizing formamide and citric acid precursors into supramolecular structures, which eventually polycondensed into a homogeneous organocatalyst for highly efficient visible light-driven hydrogen evolution with a rate of ∼16.2 mmol g(-1) h(-1) and a quantum efficiency of 0.8%. Laser photolysis and electrochemical impedance spectroscopic measurements suggested that iron-doping enabled strong electron coupling between the metal and the carbon nitride and formed unique electronic structures favoring electron mobilization along the 2D nanomaterial plane, which might facilitate the electron transfer process in the photocatalytic system and lead to efficient H2 evolution. In combination with electrochemical measurements, the electron transfer dynamics during water reduction were depicted, and the earth-abundant Fe-based catalyst may open a sustainable strategy for conversion of sunlight into hydrogen energy and cope with current challenging energy issues worldwide.

The complete mitochondrial genome sequence of Trichopodus leerii (Perciformes: Osphronemidae) and phylogenetic studies of Osphronemidae.

Trichopodus leerii has been given many popular names in the ornament market, such as pearl gourami, lace gourami and mosaic gourami, which causes confusion in species identification. This species belongs in the family Osphronemidae of Perciformes. This species and its congeners are characterized by a brownish-silver body, covered in a pearl-like pattern. In this study, we first determined and described the complete mitogenome sequence of T. leerii, which is 16,472 bp in length. The overall base composition is 29.2%, 27.3%, 28.0% and 15.5% for A, C, T and G, respectively, with a slight bias in the AT content (57.2%). All protein-coding genes share the start codon ATG and most of them have TAA or TAG as the stop codon, except ND4 and ND6 use an incomplete stop codon T. Maximum likelihood tree and Bayesian analyses based on partitioned nucleotide sequences of 12 mitochondrial protein-coding genes were constructed, and both yielded identical topologies. These results are expected to provide useful molecular data for species identification and further phylogenetic studies of Osphronemidae and Perciformes.

Exosomes secreted by human-induced pluripotent stem cell-derived mesenchymal stem cells attenuate limb ischemia by promoting angiogenesis in mice.

INTRODUCTION: 'Patient-specific' induced pluripotent stem cells (iPSCs) are attractive because they can generate abundant cells without the risk of immune rejection for cell therapy. Studies have shown that iPSC-derived mesenchymal stem cells (iMSCs) possess powerful proliferation, differentiation, and therapeutic effects. Recently, most studies indicate that stem cells exert their therapeutic effect mainly through a paracrine mechanism other than transdifferentiation, and exosomes have emerged as an important paracrine factor for stem cells to reprogram injured cells. The objective of this study was to evaluate whether exosomes derived from iMSCs (iMSCs-Exo) possess the ability to attenuate limb ischemia and promote angiogenesis after transplantation into limbs of mice with femoral artery excision. METHODS: Human iPSCs (iPS-S-01, C1P33, and PCKDSF001C1) were used to differentiate into iMSCs in a modified one-step method. iMSCs were characterized by flow cytometry and multipotent differentiation potential analysis. Ultrafiltration combined with a purification method was used to isolate iMSCs-Exo, and transmission electron microscopy and Western blotting were used to identify iMSCs-Exo. After establishment of mouse hind-limb ischemia with excision of femoral artery and iMSCs-Exo injection, blood perfusion was monitored at days 0, 7, 14, and 21; microvessel density in ischemic muscle was also analyzed. In vitro migration, proliferation, and tube formation experiments were used to analyze the ability of pro-angiogenesis in iMSCs-Exo, and quantitative reverse-transcriptase polymerase chain reaction and enzyme-linked immunosorbent assay were used to identify expression levels of angiogenesis-related molecules in human umbilical vein endothelial cells (HUVECs) after being cultured with iMSCs-Exo. RESULTS: iPSCs were efficiently induced into iMSC- with MSC-positive and -negative surface antigens and osteogenesis, adipogenesis, and chondrogenesis differentiation potential. iMSCs-Exo with a diameter of 57 ± 11 nm and expressed CD63, CD81, and CD9. Intramuscular injection of iMSCs-Exo markedly enhanced microvessel density and blood perfusion in mouse ischemic limbs, consistent with an attenuation of ischemic injury. In addition, iMSCs-Exo could activate angiogenesis-related molecule expression and promote HUVEC migration, proliferation, and tube formation. CONCLUSION: Implanted iMSCs-Exo was able to protect limbs from ischemic injury via the promotion of angiogenesis, which indicated that iMSCs-Exo may be a novel therapeutic approach in the treatment of ischemic diseases.