Upregulation of CYR61 by TGF-ß and YAP signaling exerts a counter-suppression of hepatocellular carcinoma.

Transforming growth factor-ß (TGF-ß) and Hippo signaling are two critical pathways engaged in cancer progression by regulating both oncogenes and tumor suppressors, yet how the two pathways coordinately exert their functions in the development of hepatocellular carcinoma (HCC) remains elusive. In this study, we firstly conducted an integrated analysis of public liver cancer databases and our experimental TGF-ß target genes, identifying CYR61 as a pivotal candidate gene relating to HCC development. The expression of CYR61 is downregulated in clinical HCC tissues and cell lines than that in the normal counterparts. Evidence revealed that CYR61 is a direct target gene of TGF-ß in liver cancer cells. In addition, TGF-ß-stimulated Smad2/3 and the Hippo pathway downstream effectors YAP and TEAD4 can form a protein complex on the promoter of CYR61, thereby activating the promoter activity and stimulating CYR61 gene transcription in a collaborative manner. Functionally, depletion of CYR61 enhanced TGF-ß- or YAP-mediated growth and migration of liver cancer cells. Consistently, ectopic expression of CYR61 was capable of impeding TGF-ß- or YAP-induced malignant transformation of HCC cells in vitro and attenuating HCC xenograft growth in nude mice. Finally, transcriptomic analysis indicates that CYR61 can elicit an antitumor program in liver cancer cells. Together, these results add new evidence for the crosstalk between TGF-ß and Hippo signaling and unveil an important tumor suppressor function of CYR61 in liver cancer.

Diurnally dynamic iron allocation promotes N2 fixation in marine dominant diazotroph Trichodesmium.

Trichodesmium is the dominant photoautotrophic dinitrogen (N2) fixer (diazotroph) in the ocean. Iron is an important factor limiting growth of marine diazotrophs including Trichodesmium mainly because of high iron content of its N2-fixing enzyme, nitrogenase. However, it still lacks a quantitative understanding of how dynamic iron allocation among physiological processes acts to regulate growth and N2 fixation in Trichodesmium. Here, we constructed a model of Trichodesmium trichome in which intracellular iron could be dynamically re-allocated in photosystems and nitrogenase during the daytime. The results demonstrate that the dynamic iron allocation enhances modeled N2 fixation and growth rates of Trichodesmium, especially in iron-limited conditions, albeit having a marginal impact under high iron concentrations. Although the reuse of iron during a day is an apparent cause that dynamic iron allocation can benefit Trichodesmium under iron limitation, our model reveals two important mechanisms. First, the release of iron from photosystems downregulates the intracellular oxygen (O2) production and reduces the demand of respiratory protection, a process that Trichodesmium wastefully respires carbohydrates to create a lower O2 window for N2 fixation. Hence, more carbohydrates can be used in growth. Second, lower allocation of iron to nitrogenase during early daytime, a period when photosynthesis is active and intracellular O2 is high, reduces the amount of iron that is trapped in the inactivated nitrogenase induced by O2. This mechanism further increases the iron use efficiency in Trichodesmium. Overall, our study provides mechanistic and quantitative insight into the diurnal iron allocation that can alleviate iron limitation to Trichodesmium.

Tea domain transcription factor TEAD4 mitigates TGF-ß signaling and hepatocellular carcinoma progression independently of YAP.

Tea domain transcription factor 4 (TEAD4) plays a pivotal role in tissue development and homeostasis by interacting with Yes-associated protein (YAP) in response to Hippo signaling inactivation. TEAD4 and YAP can also cooperate with transforming growth factor-ß (TGF-ß)-activated Smad proteins to regulate gene transcription. Yet, it remains unclear whether TEAD4 plays a YAP-independent role in TGF-ß signaling. Here, we unveil a novel tumor suppressive function of TEAD4 in liver cancer via mitigating TGF-ß signaling. Ectopic TEAD4 inhibited TGF-ß-induced signal transduction, Smad transcriptional activity, and target gene transcription, consequently suppressing hepatocellular carcinoma cell proliferation and migration in vitro and xenograft tumor growth in mice. Consistently, depletion of endogenous TEAD4 by siRNAs enhanced TGF-ß signaling in cancer cells. Mechanistically, TEAD4 associates with receptor-regulated Smads (Smad2/3) and Smad4 in the nucleus, thereby impairing the binding of Smad2/3 to the histone acetyltransferase p300. Intriguingly, these negative effects of TEAD4 on TGF-ß/Smad signaling are independent of YAP, as impairing the TEAD4-YAP interaction through point mutagenesis or depletion of YAP and/or its paralog TAZ has little effect. Together, these results unravel a novel function of TEAD4 in fine tuning TGF-ß signaling and liver cancer progression in a YAP-independent manner.

Optofluidic tunable broadband distributed Bragg reflector based on liquid crystal polymer composites.

A dynamically reconfigurable liquid crystal (LC) photonic device is an important research field in modern LC photonics. We present a type of continuously tunable distributed Bragg reflector (DBR) based on LC polymer composites modulated via a novel optofluidic method. LC-templated DBR films are fabricated by photopolymerization under visible standing wave interference. The influences of the incident angle, incident light intensity, and content of ethanol as a pore-forming additive on the reflection behavior are discussed in detail. Then, the LC-templated DBR films are integrated into microfluidic channels and reversibly refilled by different organic solvents. The reconfigurable characteristics of optofluidic DBRs were demonstrated by changing the average refractive index (RI) of the mixed liquids and adjusting the flow rates, resulting in the dynamic and continuous variation of the reflection band within a specific visible light band. It is anticipated that the prototype optofluidic LC device will hopefully be applied to some specific scenarios where conventional means of regulation, such as electric, optical, and temperature fields, are unsuitable and possibly boost the development of microfluidic analysis techniques based on structural color.

N2 Fixation in Trichodesmium Does Not Require Spatial Segregation from Photosynthesis.

The dominant marine filamentous N2 fixer, Trichodesmium, conducts photosynthesis and N2 fixation during the daytime. Because N2 fixation is sensitive to O2, some previous studies suggested that spatial segregation of N2 fixation and photosynthesis is essential in Trichodesmium. However, this hypothesis conflicts with some observations where all the cells contain both photosystems and the N2-fixing enzyme nitrogenase. Here, we construct a systematic model simulating Trichodesmium metabolism, showing that the hypothetical spatial segregation is probably useless in increasing the Trichodesmium growth and N2 fixation, unless substances can efficiently transfer among cells with low loss to the environment. The model suggests that Trichodesmium accumulates fixed carbon in the morning and uses that in respiratory protection to reduce intracellular O2 during the mid-daytime, when photosynthesis is downregulated, allowing the occurrence of N2 fixation. A cell membrane barrier against O2 and alternative non-O2 evolving electron transfer also contribute to maintaining low intracellular O2. Our study provides a mechanism enabling N2 fixation despite the presence of photosynthesis across Trichodesmium. IMPORTANCE The filamentous Trichodesmium is a globally prominent marine nitrogen fixer. A long-standing paradox is that the nitrogen-fixing enzyme nitrogenase is sensitive to oxygen, but Trichodesmium conducts both nitrogen fixation and oxygen-evolving photosynthesis during the daytime. Previous studies using immunoassays reported that nitrogenase was limited in some specialized Trichodesmium cells (termed diazocytes), suggesting the necessity of spatial segregation of nitrogen fixation and photosynthesis. However, attempts using other methods failed to find diazocytes in Trichodesmium, causing controversy on the existence of the spatial segregation. Here, our physiological model shows that Trichodesmium can maintain low intracellular O2 in mid-daytime and achieve feasible nitrogen fixation and growth rates even without the spatial segregation, while the hypothetical spatial segregation might not be useful if substantial loss of substances to the environment occurs when they transfer among the Trichodesmium cells. Our study then suggests a possible mechanism by which Trichodesmium can survive without the spatial segregation.

Diverse Subclade Differentiation Attributed to the Ubiquity of Prochlorococcus High-Light-Adapted Clade II.

Prochlorococcus is the key primary producer in marine ecosystems, and the high-light-adapted clade II (HLII) is the most abundant ecotype. However, the genomic and ecological basis of Prochlorococcus HLII in the marine environment has remained elusive. Here, we show that the ecologically coherent subclade differentiation of HLII corresponds to genomic and ecological characteristics on the basis of analyses of 31 different strains of HLII, including 12 novel isolates. Different subclades of HLII with different core and accessory genes were identified, and their distribution in the marine environment was explored using the TARA Oceans metagenome database. Three major subclade groups were identified, viz., the surface group (HLII-SG), the transition group (HLII-TG), and the deep group (HLII-DG). These subclade groups showed different temperature ranges and optima for distribution. In regression analyses, temperature and nutrient availability were identified as key factors affecting the distribution of HLII subclades. A 35% increase in the relative abundance of HLII-SG by the end of the 21st century was predicted under the Representative Concentration Pathway 8.5 scenario. Our results show that the ubiquity and distribution of Prochlorococcus HLII in the marine environment are associated with the differentiation of diverse subclades. These findings provide insights into the large-scale shifts in the Prochlorococcus community in response to future climate change. IMPORTANCEProchlorococcus is the most abundant oxygenic photosynthetic microorganism on Earth, and high-light-adapted clade II (HLII) is the dominant ecotype. However, the factors behind the dominance of HLII in the vast oligotrophic oceans are still unknown. Here, we identified three distinct groups of HLII subclades, viz., the surface group (HLII-SG), the transition group (HLII-TG), and the deep group (HLII-DG). We further demonstrated that the ecologically coherent subclade differentiation of HLII corresponds to genomic and ecological characteristics. Our study suggests that the differentiation of diverse subclades underlies the ubiquity and distribution of Prochlorococcus HLII in the marine environment and provides insights into the shifts in the Prochlorococcus community in response to future climate change.

Reconfigurable polymer-templated liquid crystal holographic gratings via visible-light recording.

Polymer-templated nematic liquid crystal (LC) holographic gratings via visible-light recording are presented in the presence of reactive mesogens (RMs) and rose bengal (RB)/N-phenylglycine (NPG) photoinitiation systems. By optimizing the concentration of RMs in the polymer-templated LC gratings, the template after being washed out can be refilled with suitable fluidic components. And the dependence of the first-order diffraction efficiency (DE) on the concentration of RB and NPG molecules was discussed in detail. The polarization-dependency of diffraction properties was also investigated. It is revealed that the diffractive behaviors of polymer-templated LC gratings can be dynamically reconfigured by varying temperature or refilling organic solutions with different refractive index (RI). Furthermore, the potential for recording holograms using green light is explored. We expect that the reconfigurable polymer-templated LC gratings fabricated via visible-light interference would provide a facile approach to regulate the diffraction properties of holographic gratings apart from electric field, thus paving a way towards a class of novel anti-counterfeiting devices.

KLF2 inhibits TGF-ß-mediated cancer cell motility in hepatocellular carcinoma.

Feedback regulation plays a pivotal role in determining the intensity and duration of TGF-ß signaling and subsequently affecting the pathophysiological roles of TGF-ß, including those in liver malignancy. KLF2, a member of the Krüppel-like factor (KLF) family transcription factors, has been implicated in impeding hepatocellular carcinoma (HCC) development. However, the underlying molecular mechanisms are not fully understood. In the present study, we found that TGF-ß stimulates the expression of KLF2 gene in several HCC cell lines. KLF2 protein is able to inhibit TGF-ß/Smad signaling in HCC cells as assessed by luciferase reporter assay. Further studies indicated that KLF2 inhibits the transcriptional activity of Smad2/3 and Smad4 and ameliorates TGF-ß-induced target gene expression, therefore creating a novel negative feedback loop in TGF-ß signaling. Functionally, stably expression of KLF2 in HCCLM3 cells attenuated TGF-ß-induced cancer cell motility in wound-healing and transwell assays by interfering with TGF-ß-mediated upregulation of MMP2. Together, our results revealed that KLF2 protein has a tumor-suppressive function in HCC through a negative feedback loop over TGF-ß signaling.

Real-time generation of dynamically patterned cholesteric liquid crystal fingerprint textures based on photoconductive effect.

We present a convenient approach to facilitate the real-time generation of updatable dynamically patterned cholesteric liquid crystal (CLC) fingerprint textures based on photoconductive effect. The photoconductive Bi12SiO20 (BSO) substrate acts as virtual electrode to obtain the desired states of CLCs by both electric and light fields. Owing to different boundary conditions, the switching of four states; that is, planar, fingerprint, metastable, and homeotropic states, and the rotation of fingerprint stripes can be achieved in planar alignment (PA) cell and hybrid alignment (HA) cell, respectively. With the aid of a digital micro-mirror (DMD)-based exposure system, binary and gray-scale images were successfully written and updated by light upon suitable voltages. This work provides an alternative approach to photoaddress CLC fingerprint patterns, without needing special photoalignment agents or photoresponsitive chiral dopants. We expect that it could be employed in the manipulation of nano/micro-objects by light.

Effect of the population density on belowground bud bank of a rhizomatous clonal plant Leymus secalinus in Mu Us sandy land.

Clonal propagation is the main strategy for clonal plants to adapt to wind-sand habitat, and underground bud bank could reflect the potential ability of clonal propagation. However, the effects of population density on belowground bud bank are unknown, hindering efforts in the process of dune stabilization. We investigated the horizontal density and vertical distribution of belowground bud bank of a typical rhizomatous grass Leymus secalinus, and soil water content in four dune types with different population density (dune type I: 11.2 ± 1.7 no. m-2, type II: 24.2 ± 2.6 no. m-2, type III: 40.0 ± 4.0 no. m-2, and type IV: 53.5 ± 7.2 no. m-2) in Mu Us sandy land. Our results showed that (1) total bud density of population increased markedly with increasing population density, but it did not exhibit significant difference between dune types III and IV, where density was about 130 buds m-2; and tiller bud density of population first increased, then decreased, and reached a maximum in dune type III. (2) Total bud density per individual in dune type III was significantly larger than that in other dune types (P < 0.05), whereas rhizome and tiller bud density per individual did not show significant differences in dune types II, III and IV (P > 0.05). (3) Buds tended to be concentrated at 10-30 cm soil layer in all dune types, and be buried deeper in dune types III and IV than that in dune types I and II. (4) No pronounced relationship was shown between bud density and soil water content in 10-30 cm soil layer with increasing population density. Our results suggest that moderate population density (40.0 ± 4.0 no. m-2) significantly increase the bud bank density of L. secalinus population and individual. Soil water content was not the main factor responsible for the density of L. secalinus bud bank. These results can provide important information for implementation of effective sand fixation measures and species selection for desertification control in semiarid sandy land ecosystems.

beta-Naphthoflavone protects from peritonitis by reducing TNF-alpha-induced endothelial cell activation.

ß-Naphthoflavone (ß-NF), a ligand of the aryl hydrocarbon receptor, has been shown to possess anti-oxidative properties. We investigated the anti-oxidative and anti-inflammatory potential of ß-NF in human microvascular endothelial cells treated with tumor necrosis factor-alpha (TNF-α). Pretreatment with ß-NF significantly inhibited TNF-α-induced intracellular reactive oxygen species, translocation of p67(phox), and TNF-α-induced monocyte binding and transmigration. In addition, ß-NF significantly inhibited TNF-α-induced ICAM-1 and VCAM-1 expression. The mRNA expression levels of the inflammatory cytokines TNF-α and IL-6 were reduced by ß-NF, as was the infiltration of white blood cells, in a peritonitis model. The inhibition of adhesion molecules was associated with suppressed nuclear translocation of NF-κB p65 and Akt, and suppressed phosphorylation of ERK1/2 and p38. The translocation of Egr-1, a downstream transcription factor involved in the MEK-ERK signaling pathway, was suppressed by ß-NF treatment. Our findings show that ß-NF inhibits TNF-α-induced NF-kB and ERK1/2 activation and ROS generation, thereby suppressing the expression of adhesion molecules. This results in reduced adhesion and transmigration of leukocytes in vitro and prevents the infiltration of leukocytes in a peritonitis model. Our findings also suggest that ß-NF might prevent TNF-α-induced inflammation.

Pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension--A single-center experience in Taiwan.

BACKGROUND/PURPOSE: Pulmonary endarterectomy (PEA) is a potentially curative surgical procedure for patients with chronic thromboembolic pulmonary hypertension. The aim of this study is to review our institutional experience with this operation. METHODS: We conducted a retrospective review of PEA performed at our institution between January 2005 and December 2013. The measured outcomes were inhospital complications, improvement in cardiac function and exercise capacity, and actuarial survival after PEA. RESULTS: Ten consecutive patients (7 women, 3 men) underwent PEA with a mean age of 59.9 ± 12.9 years. The preoperative New York Heart Association functional class (NYHA FC) for these patients was either Class III (n = 6) or Class IV (n = 4). The period from symptom onset to diagnosis was 34.3 ± 37.9 months, and that from diagnosis to operation was 31.4 ± 46.8 months. After PEA, the duration of intensive care unit stay and hospital stay prior to discharge were 9.7 ± 5.7 days and 18.7 ± 7.4 days, respectively. Postoperative complications included reperfusion lung edema (n = 3) and pneumonia (n = 1), and all recovered with medical therapy. After a mean follow-up of 48.4 ± 35.1 months, all patients showed marked improvements in their clinical status and were still alive without evidence of disease recurrence. CONCLUSION: With proper patient selection, the cooperation of a multidisciplinary team, and meticulous postoperative management, PEA can be conducted safely with relatively low risk at a center with limited experience with the procedure.