Repression of rRNA gene transcription by endothelial SPEN deficiency normalizes tumor vasculature via nucleolar stress.

Human cancers induce a chaotic, dysfunctional vasculature that promotes tumor growth and blunts most current therapies; however, the mechanisms underlying the induction of a dysfunctional vasculature have been unclear. Here, we show that split end (SPEN), a transcription repressor, coordinates rRNA synthesis in endothelial cells (ECs) and is required for physiological and tumor angiogenesis. SPEN deficiency attenuated EC proliferation and blunted retinal angiogenesis, which was attributed to p53 activation. Furthermore, SPEN knockdown activated p53 by upregulating noncoding promoter RNA (pRNA), which represses rRNA transcription and triggers p53-mediated nucleolar stress. In human cancer biopsies, a low endothelial SPEN level correlated with extended overall survival. In mice, endothelial SPEN deficiency compromised rRNA expression and repressed tumor growth and metastasis by normalizing tumor vessels, and this was abrogated by p53 haploinsufficiency. rRNA gene transcription is driven by RNA polymerase I (RNPI). We found that CX-5461, an RNPI inhibitor, recapitulated the effect of Spen ablation on tumor vessel normalization and combining CX-5461 with cisplatin substantially improved the efficacy of treating tumors in mice. Together, these results demonstrate that SPEN is required for angiogenesis by repressing pRNA to enable rRNA gene transcription and ribosomal biogenesis and that RNPI represents a target for tumor vessel normalization therapy of cancer.

p-AKT/VPS4B regulates the small extracellular vesicle size in venous malformation endothelial cells.

OBJECTIVE: Small extracellular vesicle (sEV)-mediated intercellular communication is increasingly the key for the understanding of venous malformations (VMs). This study aims to clarify the detailed changes of sEVs in VMs. SUBJECTS AND METHODS: Fifteen VM patients without treatment history and twelve healthy donors were enrolled in the study. sEVs were isolated from both fresh lesions and cell supernatant, and were examined by western blotting, nanoparticle tracking analysis and transmission electron microscopy. Western blot analysis, immunohistochemistry and immunofluorescence were adopted to screening candidate regulator of sEV size. Specific inhibitors and siRNA were employed to validate the role of dysregulated p-AKT/vacuolar protein sorting-associated protein 4B (VPS4B) signaling on the size of sEVs in endothelial cells. RESULTS: The size of sEVs derived from both VM lesion tissues and cell model was significantly increased. VPS4B, whose expression level was mostly significantly downregulated in VM endothelial cells, was responsible for the size change of sEVs. Targeting abnormal AKT activation corrected the size change of sEVs by recovering the expression level of VPS4B. CONCLUSION: Downregulated VPS4B in endothelial cells, resulted from abnormally activated AKT signaling, contributed to the increased size of sEVs in VMs.

A histological study of vascular wall resident stem cells in venous malformations.

Vascular wall resident stem cells (VW-SCs) play a key role in vascular formation and remodeling under both physiological and pathological situations. They not only serve as a reservoir to supply all types of vascular cells needed, but also regulate vascular homeostasis by paracrine effects. Venous malformations (VMs) are common congenital vascular malformations which are just characterized by the deficient quantity and abnormal function of vascular cells. However, the existence and role of VW-SCs in VMs is still unclear at present. In this study, the level and distribution of VW-SCs in 22 specimens of VMs were measured by immunochemistry, double-labeling immunofluorescence, and qPCR, followed by the Spearman rank correlation test. We found that both the protein and mRNA expression levels of CD34, vWF, VEGFR2, CD44, CD90, and CD105 were significantly downregulated in VMs compared with that in normal venules. VW-SCs were sporadically distributed or even absent within and outside the endothelium of VMs. The expression of the VW-SC-related markers was positively correlated with the density of both endothelial cells and perivascular cells. All those results and established evidence indicated that VW-SCs were more sporadically distributed with fewer amounts in VMs, which possibly contributing to the deficiency of vascular cells in VMs.

Tissue Inhibitor of Metalloprotease-1 (TIMP-1) Regulates Adipogenesis of Adipose-derived Stem Cells (ASCs) via the Wnt Signaling Pathway in an MMP-independent Manner.

Tissue inhibitor of metalloprotease-1 (TIMP-1) is a tissue inhibitor of matrix metalloproteinases (MMPs). It however exerts multiple effects on biological processes, such as cell growth, proliferation, differentiation and apoptosis, in an MMP-independent manner. This study aimed to examine the role of TIMP-1 in adipogenesis of adipose-derived stem cells (ASCs) and the underlying mechanism. We knocked down the TIMP-1 gene in ASCs through lentiviral vectors encoding TIMP-1 small interfering RNA (siRNA), and then found that the knockdown of TIMP-1 in ASCs promoted the adipogenic differentiation of stem cells and inhibited the Wnt/ß-catenin signaling pathway in ASCs. We also noted that mutant TIMP-1 without the inhibitory activity on MMPs promoted the activation of Wnt/ß-catenin pathway as well as the recombinant wild type TIMP-1 did, which indicated that the effect of TIMP-1 on Wnt/ß-catenin pathway was MMP-independent. Our study suggested that TIMP-1 negatively regulated the adipogenesis of ASCs via the Wnt/ß-catenin signaling pathway in an MMP-independent manner.

Genome-wide identification and characterization of long non-coding RNAs responsive to Dickeya zeae in rice.

Plant long non-coding RNA (lncRNA) is a type of newly emerging epigenetic regulator playing a critical role in plant growth, development, and biotic stress responses. However, it is unknown whether lncRNAs are involved in resistance responses between rice and Dickeya zeae, a bacterial agent causing rice foot rot disease. In this study, RNA-seq was performed to uncover the co-expression regulating networks mediated by D. zeae responsive lncRNAs and their candidate target genes. Of the 4709 lncRNAs identified, 2518 and 2191 were up- and down-regulated in response to D. zeae infection, respectively. Expression changes of 17 selected lncRNAs and their predicted targets with a potential role in defense response were investigated by qPCR. The expression levels of five lncRNAs were up-regulated while their cognate candidate target genes were down-regulated upon D. zeae infection. In addition, several lncRNAs were predicted to be target mimics of osa-miR396 and osa-miR156. These results suggest that lncRNAs might play a role in response to D. zeae infection by regulating the transcript levels of their targets and miRNAs in rice.

Establishment of Acute Immunological Liver Injury Wistar Rat Model Induced by Concanavalin A / 广州中医药大学学报

Objective To explore the dosage and injection method of concanavalin A(Con A) for inducing Wistar rats into the acute hepatic injury model. Methods (1)According to the dosage of Con A, 42 Wistar rats were randomly divided into groups A, B, C, D, E, N, 7 rats in each group. Group N was given tail intravenous injection of normal saline as normal control group. Groups A, B, C, D, E were given intravenous injection of 4, 8, 16, 30, 40 mg/kg of Con A respectively. At the 8th hour after modeling, the levels of alanine transaminase(ALT), aspartate aminotransferase(AST), albumin(ALB), interleukin(IL)-2 , IL-10, interferon (IFN)-γ, and tumor necrosis factor(TNF)-αwere detected. And HE staining was used to observe the pathological feature of hepatic tissue. (2)According to the injection method of Con A, 21 Wistar rats were randomly divided into normal control group, intraperitoneal injection group and tail intravenous injection group, 7 rats in each group. The dosage of Con A for the rats in intraperitoneal injection group and tail intravenous injection group was 16 mg/kg. At the 8th hour after modeling, the levels of serum ALT, AST, and ALB were determined. Results The number of abnormal deaths in various dose Con A groups at the end of each experiment was 0 in groups A, B, C, and 2 in group D, and 7 in group E. A small amount of spotty necrosis, inflammatory cell infiltration, and hepatic lobule with almost integrity of structure were found in groups A, B, while obvious bridging-like necrosis was seen in groups C, D. Serum ALT, AST, and ALB levels in intraperitoneal injection group had no statistically significant difference as compared with the normal control group. Conclusion Tail intravenous injection of 16 mg/kg of Con A can be used to induce an acute immunological liver injury rat model successfully.

Synchronous bilateral multifocal acinic cell carcinoma of parotid gland: case report and review of the literature.

A 55-year-old woman presented with a 2-year history of slow growing painless masses in both sides of the preauricular area. Ultrasound scanning of the bilateral parotid region revealed multiple tumors in both sides of the parotid gland. After superficial parotidectomy, selective neck dissection of levels II and III were performed on the left side of the parotid gland, and superficial parotidectomy was performed on the right side. Histopathologic examination revealed both of the sides of parotid gland tumors to be acinic cell carcinoma. We discuss the clinicopathologic findings of synchronous bilateral multifocal acinic cell carcinoma of the parotid gland.