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Most traits are polygenic, and the contributing loci can be identified by genome-wide association studies. The genetic basis of adaptation (adaptive architecture) is, however, difficult to characterize. Here, we propose to study the adaptive architecture of traits by monitoring the evolution of their phenotypic variance during adaptation to a new environment in well-defined laboratory conditions. Extensive computer simulations show that the evolution of phenotypic variance in a replicated experimental evolution setting can distinguish between oligogenic and polygenic adaptive architectures. We compared gene expression variance in male Drosophila simulans before and after 100 generations of adaptation to a novel hot environment. The variance change in gene expression was indistinguishable for genes with and without a significant change in mean expression after 100 generations of evolution. We suggest that the majority of adaptive gene expression evolution can be explained by a polygenic architecture. We propose that tracking the evolution of phenotypic variance across generations can provide an approach to characterize the adaptive architecture. [ABSTRACT FROM AUTHOR]

Most organismal phenotypes have a polygenic basis, which enables adaptive phenotypic responses on ecological time scales. While adaptive phenotypic changes are highly parallel in replicate populations, this does not apply to the contributing loci. In particular for small populations, the same phenotypic shift can be fueled by different sets of alleles at alternative loci (genetic redundancy). Although this phenomenon is empirically well supported, the molecular basis of the genetic redundancy is not yet understood. To fill this gap, we compared the heterogeneity of the evolutionary transcriptomic and metabolomic response in ten Drosophila simulans populations which evolved parallel high-level phenotypic changes in a novel temperature environment but used different allelic combinations of alternative loci. We showed that the metabolome evolved more parallel than the transcriptome, confirming a hierarchical organization of molecular phenotypes. Different sets of genes responded in each evolved population but led to the enrichment of similar biological functions and a consistent metabolic profile. Since even the metabolomic response was still highly heterogeneous across evolved populations, we propose that selection may operate on pathways/networks. [ABSTRACT FROM AUTHOR]

Shifts in trait means are widely considered as evidence for adaptive responses, but the impact on phenotypic variance remains largely unexplored. Classic quantitative genetics provides a theoretical framework to predict how selection on phenotypic mean affects the variance. In addition to this indirect effect, it is also possible that the variance of the trait is the direct target of selection, but experimentally characterized cases are rare. Here, we studied gene expression variance of Drosophila simulans males before and after 100 generations of adaptation to a novel hot laboratory environment. In each of the two independently evolved populations, the variance of 125 and 97 genes was significantly reduced. We propose that the drastic loss in environmental complexity from nature to the laboratory may have triggered selection for reduced variance. Our observation that selection could drive changes in the variance of gene expression could have important implications for studies of adaptation processes in natural and experimental populations. [ABSTRACT FROM AUTHOR]

Abstract There has been increasing interest in Synchronous Computer-Mediated Communication (SCMC) as a resource for English learning, which can increase the availability of academic help outside of the classroom and offer opportunities to communicate with English speakers around the world. This study investigated the effects of online tutoring on college students' speaking proficiency and their meaning negotiation processes. Participants were 25 second-year, non-native English-speaking college students at a university of science and technology in central Taiwan. Data collected included pre- and post-tests of oral proficiency, as well as records of communication between tutors and students. A paired sample t -test was conducted to measure the students' speaking progress, while Varonis and Gass' (1985) interactional modification model was adopted to analyze their meaning negotiation processes. The findings revealed that both the high proficiency (HP) and low proficiency (LP) groups made significant progress in speaking fluency, vocabulary, and accuracy and structure in the meaning negotiation processes, while only the LP group showed significant progress in pronunciation and comprehension. The analysis also revealed significant differences in meaning negotiation processes between the HP and LP groups. It was found that students' negotiated turns produced plentiful language output, suggesting that meaning negotiation provided a rich avenue for them to practice their oral skills through constant rephrasing and elaboration. [ABSTRACT FROM AUTHOR]

Abstract: Early metastasis is one of the major causes of mortality among patient with lung cancer. The process of tumor metastasis involves a cascade of events, including epithelial-mesenchymal transition, tumor cell migration and invasion, and angiogenesis. To specifically suppress tumor invasion and angiogenesis, two nucleolin aptamer-siRNA chimeras (aptNCL-SLUGsiR and aptNCL-NRP1siR) were used to block key signaling pathways involved in lung cancer metastasis that are pivotal to metastatic tumor cells but not to normal cells under ordinary physiologic conditions. Through nucleolin-mediated endocytosis, the aptNCL-siRNA chimeras specifically and significantly knocked down the expressions of SLUG and NRP1 in nucleolin-expressing cancer cells. Furthermore, simultaneous suppression of SLUG and NRP1 expressions by the chimeras synergistically retarded cancer cell motility and invasive ability. The synergistic effect was also observed in a xenograft mouse model, wherein the combined treatment using two chimeras suppressed tumor growth, the invasiveness, circulating tumor cell amount, and angiogenesis in tumor tissue without affecting liver and kidney functions. This study demonstrates that combined treatment of aptNCL-SLUGsiR and aptNCL-NRP1siR can synergistically suppress lung cancer cell invasion, tumor growth and angiogenesis by cancer-specific targeting combined with gene-specific silencing. [Copyright &y& Elsevier]

According to the Centers for Disease Control and Prevention, tooth caries is a common problem affecting 9 out of every 10 adults worldwide. Dentin regeneration has since become one of the pressing issues in dentistry with tissue engineering emerging as a potential solution for enhancing dentin regeneration. In this study, we fabricated cell blocks with human dental pulp stem cells (hDPSCs)-laden alginate/fish gelatin hydrogels (Alg/FGel) at the center of the cell block and human umbilical vascular endothelial cells (HUVEC)-laden Si ion-infused fish gelatin methacrylate (FGelMa) at the periphery of the cell block. 1H NMR and FTIR results showed the successful fabrication of Alg/FGel and FGelMa. In addition, Si ions in the FGelMa were noted to be bonded via covalent bonds and the increased number of covalent bonds led to an increase in mechanical properties and improved degradation of FGelMa. The Si-containing FGelMa was able to release Si ions, which subsequently significantly not only enhanced the expressions of angiogenic-related protein, but also secreted some cytokines to regulate odontogenesis. Further immunofluorescence results indicated that the cell blocks allowed interactions between the HUVEC and hDPSCs, and taken together, were able to enhance odontogenic-related markers' expression, such as alkaline phosphatase (ALP), dentin matrix phosphoprotein-1 (DMP-1), and osteocalcin (OC). Subsequent Alizarin Red S stain confirmed the benefits of our cell block and demonstrated that such a novel combination and modification of biomaterials can serve as a platform for future clinical applications and use in dentin regeneration. [ABSTRACT FROM AUTHOR]

High‐risk neuroblastoma (NB) is responsible for a disproportionate number of childhood deaths due to cancer. One indicator of high‐risk NB is amplification of the neural MYC (MYCN) oncogene, which is currently therapeutically intractable. Identification of anaplastic lymphoma kinase (ALK) as an NB oncogene raised the possibility of using ALK tyrosine kinase inhibitors (TKIs) in treatment of patients with activating ALK mutations. 8–10% of primary NB patients are ALK‐positive, a figure that increases in the relapsed population. ALK is activated by the ALKAL2 ligand located on chromosome 2p, along with ALK and MYCN, in the "2p‐gain" region associated with NB. Dysregulation of ALK ligand in NB has not been addressed, although one of the first oncogenes described was v‐sis that shares > 90% homology with PDGF. Therefore, we tested whether ALKAL2 ligand could potentiate NB progression in the absence of ALK mutation. We show that ALKAL2 overexpression in mice drives ALK TKI‐sensitive NB in the absence of ALK mutation, suggesting that additional NB patients, such as those exhibiting 2p‐gain, may benefit from ALK TKI‐based therapeutic intervention. SYNOPSIS: ALK receptor tyrosine kinase (RTK) is aberrantly activated in childhood cancer neuroblastoma (NB), acting in concert with the neural MYC (MYCN) oncogene. As shown here, the recently‐identified ALK ligand ALKAL2 is sufficient to drive ALK‐dependent NB development, irrespective of oncogenic mutations. ALKAL2 ligand stimulates ALK RTK signaling in human NB cells, as measured by RNA‐Seq, global proteomics and phospho‐proteomics.ALK F1178S gain‐of‐function mutation cooperates with MYCN to drive NB in mice.Transgenic ALKAL2 increases MYCN‐driven NB in the presence of wild‐type ALK.ALKAL2‐driven neuroblastoma is sensitive to ALK inhibitor treatment. [ABSTRACT FROM AUTHOR]

Simple Summary: The insulin-like growth factor 1 receptor (IGF1R) is a receptor tyrosine kinase (RTK) widely expressed in many cancers, including the pediatric cancer neuroblastoma. Aberrant activation of the anaplastic lymphoma kinase (ALK) RTK by activating point mutations or amplification is identified in 5–12% of neuroblastomas. Here, we investigated IGF1R in ALK-driven neuroblastoma, with the aim of understanding its contribution and exploring its potential for targeted therapy. Using ALK-driven neuroblastoma cell lines, we show that ALK-mutated cells are more sensitive to IGF1R inhibition than ALK-amplified cells, and a synergistic effect is obtained when combining ALK and IGF1R inhibitors. Mechanistically, in ALK-mutated neuroblastoma cells, both ALK and IGF1R contribute significantly to the activation of the downstream PI3K-AKT and RAS-MAPK signaling pathways. Our results suggest that differential activation of signaling downstream of the ALK and IGF1R pathways is in part due to preferential recruitment of adaptor proteins. Aberrant activation of anaplastic lymphoma kinase (ALK) by activating point mutation or amplification drives 5–12% of neuroblastoma (NB). Previous work has identified the involvement of the insulin-like growth factor 1 receptor (IGF1R) receptor tyrosine kinase (RTK) in a wide range of cancers. We show here that many NB cell lines exhibit IGF1R activity, and that IGF1R inhibition led to decreased cell proliferation to varying degrees in ALK-driven NB cells. Furthermore, combined inhibition of ALK and IGF1R resulted in synergistic anti-proliferation effects, in particular in ALK-mutated NB cells. Mechanistically, both ALK and IGF1R contribute significantly to the activation of downstream PI3K-AKT and RAS-MAPK signaling pathways in ALK-mutated NB cells. However, these two RTKs employ a differential repertoire of adaptor proteins to mediate downstream signaling effects. We show here that ALK signaling led to activation of the RAS-MAPK pathway by preferentially phosphorylating the adaptor proteins GAB1, GAB2, and FRS2, while IGF1R signaling preferentially phosphorylated IRS2, promoting activation of the PI3K-AKT pathway. Together, these findings reveal a potentially important role of the IGF1R RTK in ALK-mutated NB and that co-targeting of ALK and IGF1R may be advantageous in clinical treatment of ALK-mutated NB patients. [ABSTRACT FROM AUTHOR]

Abstract: A limitation with the use of polymers as stent matrices is their inherent mechanical weakness. In this study, a polymeric stent, made from chitosan-based films fixed by genipin which has a cyclic molecular structure, was developed (the genipin stent). The mechanical properties of the genipin stent were investigated; its counterpart fixed by a linear epoxy compound (the epoxy stent) and a commercially available metallic stent were used as controls. The results indicated that the cyclic crosslinking structures formed within the genipin stent matrix were beneficiary to the improvement of its mechanical property. Additionally, the tolerable compression load of the genipin stent was superior to that of the control metallic stent. The cytotoxicity of the genipin stent was significantly lower than the epoxy stent. The deployment of the genipin stent in rabbit infrarenal abdominal aortas was performed using a French sheath. At 3 months postoperatively, the retrieved arteries remained patent; no thrombosis was observed. A nearly intact layer of endothelial cells was seen on the stent-implanted vessel wall. To evaluate its possibility as a drug delivery vehicle, sirolimus (an anti-proliferative drug) was loaded in the genipin stent. It was found that the genipin stent with heparin coating exhibited a linear sustained-release profile and the released sirolimus still possessed its original activity in inhibiting smooth muscle cell proliferation. These findings suggest that the genipin stent with enhanced mechanical strength can be used as an attractive stent platform for local drug delivery. [Copyright &y& Elsevier]

Abstract: The hydrophilic nature of hydrogel matrices makes them disadvantageous to entrap poorly soluble therapeutic agents and greatly restricts their applications as drug-delivery systems. In this study, we demonstrated that sustained delivery of lipophilic drugs in hydrogel-based devices can be readily achieved by enhancing retention of drugs within micelles. This nanoscale drug-entrapment strategy was applied to develop a polymeric drug-eluting stent. Sirolimus, a lipophilic anti-proliferative/immunosuppressive drug, was entrapped into the hydrophobic core of Pluronic L121 micelles and then blended in a chitosan-based strip and crosslinked by an epoxy compound to fabricate test stents. It was found that the use of such a nanoscale drug-entrapment strategy was able to significantly increase the loading efficiency of lipophilic drugs, prevent the drug from aggregation and beneficially reduce its initial burst release; thus, the duration of drug release was extended considerably. When implanting the stent in rabbit infrarenal abdominal aortas, in-stent restenosis was markedly reduced and less inflammatory reaction was observed, while unfavorable effects such as delayed endothelial healing caused by the overdose of sirolimus could be significantly evaded. [Copyright &y& Elsevier]

Abstract: Drug-eluting stents have emerged as a predominant percutaneous strategy in patients with coronary artery disease. However, hypersensitivity reactions caused by their nonerodable polymer coatings and bare-metal stents may result in serious clinical sequelae. In this report, a new biodegradable sirolimus-eluting stent, made from chitosan-based strips fixed by an epoxy compound, coated with a hydrophobic heparin was developed. Due to the covalent crosslinks formed in the stent matrix, the fabricated stent had a shape-memory property to memorize its permanent shape. The shape-memory ability and mechanical strength of the stent could be enhanced by increasing its degree of crosslinking. The cytocompatibility of the stent was demonstrated in vitro. The heparin coating on the stent effectively reduced platelet adhesion; additionally, it acted as a diffusion barrier and led to a nearly linear sustained-release profile of sirolimus. Cell-cycle analysis demonstrated that the released sirolimus could inhibit smooth muscle cell proliferation by inducing cell-cycle arrest in G1 phase. When compared to the unloaded stent, neointimal formation was significantly suppressed after implantation of the sirolimus-eluting stent in rabbit infrarenal abdominal aortas. These findings suggested that the developed sirolimus-eluting polymeric stent can be a potential alternative for treatment of atherosclerosis. [Copyright &y& Elsevier]

Recent development of molecular imaging probes for fluorescence-guided surgery has shown great progresses for determining tumor margin to execute the tissue resection. Here we synthesize the fluorescent gold nanoparticles conjugated with diatrizoic acid and nucleolin-targeted AS1411 aptamer. The nanoparticle conjugates exhibit high water-solubility, good biocompatibility, visible fluorescence and strong X-ray attenuation for computed tomography (CT) contrast enhancement. The fluorescent nanoparticle conjugates are applied as a molecular contrast agent to reveal the tumor location in CL1-5 tumor-bearing mice by CT imaging. Furthermore, the orange-red fluorescence emitting from the conjugates in the CL1-5 tumor can be easily visualized by the naked eyes. After the resection, the IVIS measurements show that the fluorescence signal of the nanoparticle conjugates in the tumor is greatly enhanced in comparison to that in the controlled experiment. Our work has shown potential application of functionalized nanoparticles as a dual-function imaging agent in clinical fluorescence-guided surgery. [ABSTRACT FROM AUTHOR]