Integrin CD11b Deficiency Aggravates Retinal Microglial Activation and RGCs Degeneration After Acute Optic Nerve Injury.

Neuroinflammation plays a vital role in the process of a variety of retinal ganglion cells (RGCs) degenerative diseases including traumatic optic neuropathy (TON). Retinal microglial activation is believed as a harbinger of TON, and robust microglial activation can aggravate trauma-induced RGCs degeneration, which ultimately leads to RGCs loss. Toll like receptor 4 (TLR4)-triggered inflammation is of great importance in retinal inflammatory response after optic nerve injury. CD11b on macrophage and brain microglia can inhibit TLR4-triggered inflammation. However, the functional role of CD11b in retinal microglia is not well understood. Here, using an optic nerve crush model and CD11b gene deficient mice, we found that CD11b protein expression was mainly on retinal microglia, significantly increased after optic nerve injury, and still maintained at a high level till at least 28 days post crush. Compared with wild type mice, following acute optic nerve injury, CD11b deficient retinae exhibited more exacerbated microglial activation, accelerated RGCs degeneration, less growth associated protein-43 expression, as well as more proinflammatory cytokines such as interleukin-6 and tumor necrosis factor α while less anti-inflammatory factors such as arginase-1 and interleukin-10 production. We conclude that CD11b is essential in regulating retinal microglial activation and neuroinflammatory responses after acute optic nerve injury, which is critical for subsequent RGCs degeneration and loss.

Yes-associated protein/TEA domain family member and hepatocyte nuclear factor 4-alpha (HNF4α) repress reciprocally to regulate hepatocarcinogenesis in rats and mice.

Great progress has been achieved in the study of Hippo signaling in regulating tumorigenesis; however, the downstream molecular events that mediate this process have not been completely defined. Moreover, regulation of Hippo signaling during tumorigenesis in hepatocellular carcinoma (HCC) remains largely unknown. In the present study, we systematically investigated the relationship between Yes-associated protein/TEA domain family member (YAP-TEAD) and hepatocyte nuclear factor 4-alpha (HNF4α) in the hepatocarcinogenesis of HCC cells. Our results indicated that HNF4α expression was negatively regulated by YAP1 in HCC cells by a ubiquitin proteasome pathway. By contrast, HNF4α was found to directly associate with TEAD4 to compete with YAP1 for binding to TEAD4, thus inhibiting the transcriptional activity of YAP-TEAD and expression of their target genes. Moreover, overexpression of HNF4α was found to significantly compromise YAP-TEAD-induced HCC cell proliferation and stem cell expansion. Finally, we documented the regulatory mechanism between YAP-TEAD and HNF4α in rat and mouse tumor models, which confirmed our in vitro results. CONCLUSION: There is a double-negative feedback mechanism that controls TEAD-YAP and HNF4α expression in vitro and in vivo, thereby regulating cellular proliferation and differentiation. Given that YAP acts as a dominant oncogene in HCC and plays a crucial role in stem cell homeostasis and tissue regeneration, manipulating the interaction between YAP, TEADs, and HNF4α may provide a new approach for HCC treatment and regenerative medicine. (Hepatology 2017;65:1206-1221).

OVOL2, an Inhibitor of WNT Signaling, Reduces Invasive Activities of Human and Mouse Cancer Cells and Is Down-regulated in Human Colorectal Tumors.

BACKGROUND & AIMS: Activation of WNT signaling promotes the invasive activities of several types of cancer cells, but it is not clear if it regulates the same processes in colorectal cancer (CRC) cells, or what mechanisms are involved. We studied the expression and function of OVOL2, a member of the Ovo family of conserved zinc-finger transcription factors regulated by the WNT signaling pathway, in intestinal tumors of mice and human beings. METHODS: We analyzed the expression of OVOL2 protein and messenger RNA in CRC cell lines and tissue arrays, as well as CRC samples from patients who underwent surgery at Xiamen University in China from 2009 to 2012; clinical information also was collected. CRC cell lines (SW620) were infected with lentivirus expressing OVOL2, analyzed in migration and invasion assays, and injected into nude mice to assess tumor growth and metastasis. Tandem affinity purification was used to purify the OVOL2-containing complex from CRC cells; the complex was analyzed by liquid chromatography, tandem mass spectrometry, and immunoprecipitation experiments. Gene promoter activities were measured in luciferase reporter assays. We analyzed mice with an intestine-specific disruption of Ovol2 (Ovol2(flox/+) transgenic mice), as well as Apc(min/+) mice; these mice were crossed and analyzed. RESULTS: Analysis of data from patients indicated that the levels of OVOL2 messenger RNA were significantly lower in colon carcinomas than adenomas, and decreased significantly as carcinomas progressed from grades 2 to 4. Immunohistochemical analysis of a tissue array of 275 CRC samples showed a negative association between tumor stage and OVOL2 level. Overexpression of OVOL2 in SW620 cells decreased their migration and invasion, reduced markers of the epithelial-to-mesenchymal transition, and suppressed their metastasis as xenograft tumors in nude mice; knockdown of OVOL2 caused LS174T cells to transition from epithelial to mesenchymal phenotypes. OVOL2 bound T-cell factor (TCF)4 and ß-catenin, facilitating recruitment of histone deacetylase 1 to the TCF4-ß-catenin complex; this inhibited expression of epithelial-to-mesenchymal transition-related genes regulated by WNT, such as SLUG, in CRC cell lines. OVOL2 was a downstream target of WNT signaling in LS174T and SW480 cells. The OVOL2 promoter was hypermethylated in late-stage CRC specimens from patients and in SW620 cells; hypermethylation resulted in OVOL2 down-regulation and an inability to inhibit WNT signaling. Disruption of Ovol2 in Apc(min/+) mice increased WNT activity in intestinal tissues and the formation of invasive intestinal tumors. CONCLUSIONS: OVOL2 is a colorectal tumor suppressor that blocks WNT signaling by facilitating the recruitment of histone deacetylase 1 to the TCF4-ß-catenin complex. Strategies to increase levels of OVOL2 might be developed to reduce colorectal tumor progression and metastasis.

The Wnt-ß-catenin pathway represses let-7 microRNA expression through transactivation of Lin28 to augment breast cancer stem cell expansion.

Wnt signalling through ß-catenin and the lymphoid-enhancing factor 1/T-cell factor (LEF1/TCF) family of transcription factors maintains stem cell properties in both normal and malignant tissues; however, the underlying molecular pathway involved in this process has not been completely defined. Using a microRNA microarray screening assay, we identified let-7 miRNAs as downstream targets of the Wnt-ß-catenin pathway. Expression studies indicated that the Wnt-ß-catenin pathway suppresses mature let-7 miRNAs but not the primary transcripts, which suggests a post-transcriptional regulation of repression. Furthermore, we identified Lin28, a negative let-7 biogenesis regulator, as a novel direct downstream target of the Wnt-ß-catenin pathway. Loss of function of Lin28 impairs Wnt-ß-catenin-pathway-mediated let-7 inhibition and breast cancer stem cell expansion; enforced expression of let-7 blocks the Wnt-ß-catenin pathway-stimulated breast cancer stem cell phenotype. Finally, we demonstrated that the Wnt-ß-catenin pathway induces Lin28 upregulation and let-7 downregulation in both cancer samples and mouse tumour models. Moreover, the delivery of a modified lin28 siRNA or a let-7a agomir into the premalignant mammary tissues of MMTV-wnt-1 mice resulted in a complete rescue of the stem cell phenotype driven by the Wnt-ß-catenin pathway. These findings highlight a pivotal role for Lin28/let-7 in Wnt-ß-catenin-pathway-mediated cellular phenotypes. Thus, the Wnt-ß-catenin pathway, Lin28 and let-7 miRNAs, three of the most crucial stem cell regulators, connect in one signal cascade.

A double-negative feedback loop between Wnt-ß-catenin signaling and HNF4α regulates epithelial-mesenchymal transition in hepatocellular carcinoma.

Wnt-ß-catenin signaling participates in the epithelial-mesenchymal transition (EMT) in a variety of cancers; however, its involvement in hepatocellular carcinoma (HCC) and downstream molecular events is largely undefined. HNF4α is the most prominent and specific factor maintaining the differentiation of hepatic lineage cells and a potential EMT regulator in HCC cells. However, the molecular mechanisms by which HNF4α maintains the differentiated liver epithelium and inhibits EMT have not been completely defined. In this study, we systematically explored the relationship between Wnt-ß-catenin signaling and HNF4α in the EMT process of HCC cells. Our results indicated that HNF4α expression was negatively regulated during Wnt-ß-catenin signaling-induced EMT through Snail and Slug in HCC cells. In contrast, HNF4α was found to directly associate with TCF4 to compete with ß-catenin but facilitate transcription co-repressor activities, thus inhibiting expression of EMT-related Wnt-ß-catenin targets. Moreover, HNF4α may control the switch between the transcriptional and adhesion functions of ß-catenin. Overexpression of HNF4α was found to completely compromise the Wnt-ß-catenin-signaling-induced EMT phenotype. Finally, we determined the regulation pattern between Wnt-ß-catenin signaling and HNF4α in rat tumor models. Our studies have identified a double-negative feedback mechanism controlling Wnt-ß-catenin signaling and HNF4α expression in vitro and in vivo, which sheds new light on the regulation of EMT in HCC. The modulation of these molecular processes may be a method of inhibiting HCC invasion by blocking Wnt-ß-catenin signaling or restoring HNF4α expression to prevent EMT.

Research progress of bile biomarkers and their immunoregulatory role in biliary tract cancers.

Biliary tract cancers (BTCs), including cholangiocarcinoma and gallbladder carcinoma, originate from the biliary epithelium and have a poor prognosis. Surgery is the only choice for cure in the early stage of disease. However, most patients are diagnosed in the advanced stage and lose the chance for surgery. Early diagnosis could significantly improve the prognosis of patients. Bile has complex components and is in direct contact with biliary tract tumors. Bile components are closely related to the occurrence and development of biliary tract tumors and may be applied as biomarkers for BTCs. Meanwhile, arising evidence has confirmed the immunoregulatory role of bile components. In this review, we aim to summarize and discuss the relationship between bile components and biliary tract cancers and their ability as biomarkers for BTCs, highlighting the role of bile components in regulating immune response, and their promising application prospects.

Retinal blood vessel-origin yes-associated protein (YAP) governs astrocytic maturation via leukaemia inhibitory factor (LIF).

OBJECTIVES: To testify that endothelial cells (ECs) induce astrocyte maturation by leukaemia inhibitory factor (LIF) secretion. MATERIALS AND METHODS: In vivo experiments, mice bearing floxed alleles of YAP were crossed with mice expressing a Cre recombinase driven by the endothelial Tek promoter (Tek-Cre) to finally obtain the following three genotypes: YAPf/f , Tek-Cre; YAPf/w , Tek-Cre; and YAPf/f . Retinal vascularization and astrocyte network were evaluated by whole-mount fluorescence and Western blotting. In vitro, experiments were performed in an astrocyte and human microvascular endothelial cell (HMEC-1) coculture model to analyse the mechanisms underlying the effect of endothelial YAP on astrocytes. RESULTS: In vivo, YAPf/f ;Tek-Cre mice showed delayed angiogenesis, sparse vessels and decreased glial fibrillary acidic protein (GFAP)+ astrocytes but aberrant growth of endothelial networks and immature astrocytes (platelet-derived growth factor A, PDGFRA+ astrocytes) overgrowth. In vitro, Yap deletion attenuated the LIF release that delayed the maturation of retinal astrocyte which was consistent with the results of HMEC-1-astrocyte coculture. The effect of YAP overexpression on LIF-LIFR axis in HMEC-1 interferes the GFAP expression of astrocyte. In contrast, LIF protein rescues the astrocytic GFAP expression when EC YAP was inhibited by siRNAs. CONCLUSIONS: We show that EC yes-associated protein (YAP) is not only a critical coactivator of Hippo signalling in retinal vessel development but also plays an essential role in retinal astrocyte maturation by regulating LIF production.

Low-Intensity Pulsed Ultrasound Protects Retinal Ganglion Cell From Optic Nerve Injury Induced Apoptosis via Yes Associated Protein.

Background: Low-intensity pulsed ultrasound (LIPUS) has been used in clinical studies. But little is known about its effects on the central nervous system (CNS), or its mechanism of action. Retinal ganglion cells (RGCs) are CNS neuronal cells that can be utilized as a classic model system to evaluate outcomes of LIPUS protection from external trauma-induced retinal injury. In this study, we aim to: (1) determine the pulse energy and the capability of LIPUS in RGC viability, (2) ascertain the protective role of LIPUS in optic nerve (ON) crush-induced retinal injury, and 3) explore the cellular mechanisms of RGC apoptosis prevention by LIPUS. Methods: An ON crush model was set up to induce RGC death. LIPUS was used to treat mice eyes daily, and the retina samples were dissected for immunostaining and Western blot. The expression of yes-associated protein (YAP) and apoptosis-related proteins was detected by immunostaining and Western blot in vitro and in vivo. Apoptosis of RGCs was evaluated by TUNEL staining, the survival of RGCs and retained axons were labeled by Fluoro-gold and Tuj1 antibody, respectively. Rotenone was used to set up an in vitro cellular degenerative model and siYAP was used to interfering the expression of YAP to detect the LIPUS protective function. Results: LIPUS protected RGC from loss and apoptosis in vivo and in vitro. The ratio of cleaved/pro-caspase3 also decreased significantly under LIPUS treatment. As a cellular mechanical sensor, YAP expression increased and YAP translocated to nucleus in LIPUS stimulation group, however, phospho-YAP was found to be decreased. When YAP was inhibited, the LIPUS could not protect RGC from caspase3-dependent apoptosis. Conclusion: LIPUS prevented RGCs from apoptosis in an ON crush model and in vitro cellular degenerative model, which indicates a potential treatment for further traumatic ON injury. The mechanism of protection is dependent on YAP activation and correlated with caspase-3 signaling.

Pygo2 Regulates Adiposity and Glucose Homeostasis via ß-Catenin-Axin2-GSK3ß Signaling Pathway.

Wnt/ß-catenin signaling plays a key role in regulating adipogenesis through indirectly inhibiting the expression of C/EBPα and peroxisome proliferator-activated receptor γ (PPARγ); however, the detailed molecular mechanism remains poorly understood. Moreover, the factor(s) that determines the Wnt/ß-catenin output level during adipogenesis is also not completely defined. In this study, we showed that Pygo2 exhibited a declined expression pattern during adipocyte differentiation, resulting in an attenuated Wnt/ß-catenin output level. The mechanism study indicated that Pygo2 inhibition led to the downregulation of Axin2, a constitutive Wnt target, in the cytoplasm. Consequently, Axin2-bound GSK3ß was released and translocated into the nucleus to phosphorylate C/EBPß and Snail, resulting in an increase in the DNA binding activity of C/EBPß and decreased protein stability of Snail, which subsequently activated the expression of C/EBPα and PPARγ. Consistent with this, embryonic fibroblasts from Pygo2-/- mice exhibited spontaneous adipocyte differentiation, and adipocyte precursor-specific Pygo2-deficient mice exhibited increased adiposity with decreased energy expenditure. We further showed impaired glucose tolerance and decreased systemic insulin sensitivity in Pygo2-deficient mice. Our study revealed an association between Pygo2 function and obesity or diabetes.

[Effect of ball attachments with different materials on retention of mandibular implant supported overdenture].

PURPOSE: To investigate the effect of ball attachments with different materials on retention of mandibular implant supported overdenture. METHODS: The experimental groups were divided into group A (titanium ball / titanium cap group) and group B (titanium ball / golden cap group), each group had 3 samples. A standard mandibular edentulous model was made, and the implants (4.8*10 RN SP) were embedded in the bilateral canine region. Mandibular complete dentures were made routinely and the attachments were attached. Five thousand times of insertion-separation cycles were carried out. After 200 times of cycles, the retention force was tested. The difference between 2 groups was compared by using SPSS 13.0 software package. The change of positive structure surface morphology was observed under scanning electron microscope at the beginning and the end of the experiment. RESULTS: The retention force of group A decreased from （27.00±0.16） N to （4.18±0.03） N, and the retention force of group B decreased from （21.58±0.06） N to （19.15±0.06）N. Decay of retention of group A was significantly greater than that of group B. At the end of the experiment, the globular structure of group A was severely broken, while a smooth and clear spherical structure was displayed in group B. CONCLUSIONS: The retention of mandibular implant supported overdenture decreases with the increase of insertion-separation times. The decay of retention force is related to destruction of positive structure surface. The fatigue resistance of the precious metal material is better.

MicroRNA-146a contributes to CD4+ T lymphocyte differentiation in patients with thyroid ophthalmopathy.

MicroRNA-146a (miR-146a) is associated with human inflammatory disease, such as thyroid-associated ophthalmopathy (TAO), but its role in human T cells and relevance to TAO remains ambiguous. In this study, T cells of TAO patients showed downregulated expression of miR-146a. We characterized miR-146a in T cells and examined miR-146a as a critical inhibitor of Th1 differentiation processes. MiR-146a inhibited Th1 differentiation processes and cell proliferation of T-lymphocytes. Thus, the results showed that miR-146a was a potent inhibitor of Th1 differentiation and cell proliferation of human T cells and dysregulation of miR-146a contributed to the pathogenesis of TAO.

OVOL2 antagonizes TGF-ß signaling to regulate epithelial to mesenchymal transition during mammary tumor metastasis.

Great progress has been achieved in the study of the role of TGF-ß signaling in triggering epithelial-mesenchymal transition (EMT) in a variety of cancers; however, the regulation of TGF-ß signaling during EMT in mammary tumor metastasis has not been completely defined. In the present study, we demonstrated that OVOL2, a zinc finger transcription factor, inhibits TGF-ß signaling-induced EMT in mouse and human mammary tumor cells, as well as in mouse tumor models. Data from the Oncomine databases indicated a strong negative relationship between OVOL2 expression and breast cancer progression. Moreover, our experiments revealed that OVOL2 inhibits TGF-ß signaling at multiple levels, including inhibiting Smad4 mRNA expression and inducing Smad7 mRNA expression, blocking the binding between Smad4 and target DNA, and interfering with complex formation between Smad4 and Smad2/3. These findings reveal a novel mechanism that controls the TGF-ß signaling output level in vitro and in vivo. The modulation of these molecular processes may represent a strategy for inhibiting breast cancer invasion by restoring OVOL2 expression.

Synthesis of a precursor dipeptide of RGDS (Arg-Gly-Asp-Ser) catalysed by the industrial protease alcalase.

Synthesis of Bz-Arg-Gly-NH(2) (N-benzoylargininylglycinamide) [a precursor dipeptide of RGDS (Arg-Gly-Asp-Ser)] catalysed by protease in water/organic co-solvent systems was studied. Starting substrates were N-benzoyl-L-arginine ethyl ester hydrochloride (acyl donor) and glycinamide (nucleophile). Acetonitrile was selected as the organic solvent. Alcalase, an industrial alkaline protease, was applied to the synthesis of the target dipeptide. The conditions of the synthesis reaction were optimized by examining the effects of several factors, including water content, temperature, pH, molar ratio of the substrates and reaction time, on the yield of Bz-Arg-Gly-NH(2). The optimum conditions were established to be pH 10.0, 45 degrees C, in acetonitrile/0.1 M Na(2)CO(3)/NaHCO(3) buffer system (90:10, v/v) for 1 h with a dipeptide yield of 82.9%.

New synthetic route for RGD tripeptide.

A new route was employed to synthesize RGD. First, Gly-Asp dipeptide was synthesized by a novel chemical method in two steps, including chloroacetylation of L-aspartic acid and ammonolysis of chloroacetyl L-aspartic acid. Second, Nalpha-Z- L-Arginine was reacted with Gly-Asp to synthesize RGD by the N-carboxyanhydride method. Less protected amino acids were used in this synthesis. This method possessed advantages of low cost, simplicity, and rapidity with a reasonable yield of 62% calculated from arginine. In addition, compared with the above method, a conventional solid phase method was also used to synthesize RGD, the yield was 75% calculated from the first amino acid anchored to resin.

Alcalase-catalyzed, kinetically controlled synthesis of a precursor dipeptide of RGDS in organic solvents.

The protease-catalyzed, kinetically controlled synthesis of a precursor dipeptide of RGDS, Z-Asp-Ser-NH2 in organic solvents was studied. Alcalase, an industrial alkaline protease, was used to catalyze the synthesis of the target dipeptide in water-organic cosolvents systems with Z-Asp-OMe as the acyl donor and Ser-NH2 as the nucleophile. Acetonitrile was selected as the organic solvent from acetonitrile, ethanol, methanol, DMF, DMSO, ethyl acetate, 2-methyl-2-propanol, and chloroform tested under the experimental conditions. The conditions of the synthesis reaction were optimized by examining the effects of several factors, including water content, temperature, pH, and reaction time on the Z-Asp-Ser-NH2 yields. The optimum conditions are pH 10.0, 35 degrees C, in acetonitrile/Na2CO3-NaHCO3 buffer system (85:15, v/v), 6 h, with a dipeptide yield of 75.5%.