Photo-/thermo-responsive bioink for improved printability in extrusion-based bioprinting

Extrusion-based bioprinting has demonstrated significant potential for manufacturing constructs, particularly for 3D cell culture. However, there is a greatly limited number of bioink candidates exploited with extrusion-based bioprinting, as they meet the opposing requirements for printability with indispensable rheological features and for biochemical functionality with desirable microenvironment. In this study, a blend of silk fibroin (SF) and iota-carrageenan (CG) was chosen as a cell-friendly printable material. The SF/CG ink exhibited suitable viscosity and shear-thinning properties, coupled with the rapid sol-gel transition of CG. By employing photo-crosslinking of SF, the printability with Pr value close to 1 and structural integrity of the 3D constructs were significantly improved within a matter of seconds. The printed constructs demonstrated a Young's modulus of approximately 250 kPa, making them suitable for keratinocyte and myoblast cell culture. Furthermore, the high cell adhesiveness and viability (maximum >98%) of the loaded cells underscored the considerable potential of this 3D culture scaffold applied for skin and muscle tissues, which can be easily manipulated using an extrusion-based bioprinter.

Self-Healable Adhesive Hydrogel with a Preserved Underwater Adhesive Ability Based on Histidine-Zinc Coordination and a Bioengineered Hybrid Mussel Protein

Mussels are marine organisms that are capable of constructing an underwater adhesion between their bodies and rigid structures. It is well known that mussels achieve underwater adhesion through the presence of mussel adhesive proteins (MAPs) that contain high levels of 3,4-dihydroxyphenylalanine (DOPA). Although the extraordinary underwater adhesive properties of mussels are attributed to DOPA, its capacity to play a dual role in surface adhesion and internal cohesion is inherently limited. However, mussels employ a combination of chemical moieties, not just DOPA, along with anatomical components, such as plaque and byssus, in underwater adhesion. This also involves junction proteins that connect the plaque and byssus. In this study, a novel hybrid MAP was bioengineered via the fusion of the plaque protein (foot protein type 1) and the histidine-rich domain of the junction protein (foot protein type 4). To achieve direct adhesion underwater, the adhesive should maintain surface adhesion without disintegrating. Notably, the histidine-Zn-coordinated hybrid MAP hydrogel maintained a high surface adhesion ability even after cross-linking because of the preservation of its unoxidized and non-cross-linked DOPA moieties. The formulated adhesive hydrogel system based on the bioengineered hybrid MAP exhibited self-healing properties, owing to the reversible metal coordination bonds. The developed adhesive hydrogel exhibits outstanding levels of bulk adhesion in underwater environments, highlighting its potential as an effective adhesive biomaterial. Therefore, the introduction of histidine-rich domains into MAPs may be applied in various studies to formulate mussel-inspired adhesives with self-healing properties and to fully utilize the adhesive ability of DOPA.

Aptamer-based CRISPR-Cas powered diagnostics of diverse biomarkers and small molecule targets

CRISPR-Cas systems have been widely used in genome editing and transcriptional regulation. Recently, CRISPR-Cas effectors are adopted for biosensor construction due to its adjustable properties, such as simplicity of design, easy operation, collateral cleavage activity, and high biocompatibility. Aptamers' excellent sensitivity, specificity, in vitro synthesis, base-pairing, labeling, modification, and programmability has made them an attractive molecular recognition element for inclusion in CRISPR-Cas systems. Here, we review current advances in aptamer-based CRISPR-Cas sensors. We briefly discuss aptamers and the knowledge of Cas effector proteins, crRNA, reporter probes, analytes, and applications of target-specific aptamers. Next, we provide fabrication strategies, molecular binding, and detection using fluorescence, electrochemical, colorimetric, nanomaterials, Rayleigh, and Raman scattering. The application of CRISPR-Cas systems in aptamer-based sensing of a wide range of biomarkers (disease and pathogens) and toxic contaminants is growing. This review provides an update and offers novel insights into developing CRISPR-Cas-based sensors using ssDNA aptamers with high efficiency and specificity for point-of-care setting diagnostics.

Management of Discolored Anterior Teeth with Pulp Canal Obliteration

The purpose of this article is to present the effect and follow-up results of combined single-tooth vital bleaching when discoloration is due to pulp canal obliteration. In these cases, discoloration was managed successfully via home bleaching with a customized single-tooth tray and in-office bleaching without root canal treatment.

NetMix2: A Principled Network Propagation Algorithm for Identifying Altered Subnetworks

A standard paradigm in computational biology is to leverage interaction networks as prior knowledge in analyzing high-throughput biological data, where the data give a score for each vertex in the network. One classical approach is the identification of altered subnetworks, or subnetworks of the interaction network that have both outlier vertex scores and a defined network topology. One class of algorithms for identifying altered subnetworks search for high-scoring subnetworks in subnetwork families with simple topological constraints, such as connected subnetworks, and have sound statistical guarantees. A second class of algorithms employ network propagation-the smoothing of vertex scores over the network using a random walk or diffusion process-and utilize the global structure of the network. However, network propagation algorithms often rely on ad hoc heuristics that lack a rigorous statistical foundation. In this work, we unify the subnetwork family and network propagation approaches by deriving the propagation family, a subnetwork family that approximates the sets of vertices ranked highly by network propagation approaches. We introduce NetMix2, a principled algorithm for identifying altered subnetworks from a wide range of subnetwork families. When using the propagation family, NetMix2 combines the advantages of the subnetwork family and network propagation approaches. NetMix2 outperforms other methods, including network propagation on simulated data, pan-cancer somatic mutation data, and genome-wide association data from multiple human diseases.

SuperDendrix algorithm integrates genetic dependencies and genomic alterations across pathways and cancer types

Recent genome-wide CRISPR-Cas9 loss-of-function screens have identified genetic dependencies across many cancer cell lines. Associations between these dependencies and genomic alterations in the same cell lines reveal phenomena such as oncogene addiction and synthetic lethality. However, comprehensive identification of such associations is complicated by complex interactions between genes across genetically heterogeneous cancer types. We introduce and apply the algorithm SuperDendrix to CRISPR-Cas9 loss-of-function screens from 769 cancer cell lines, to identify differential dependencies across cell lines and to find associations between differential dependencies and combinations of genomic alterations and cell-type-specific markers. These associations respect the position and type of interactions within pathways: for example, we observe increased dependencies on downstream activators of pathways, such as NFE2L2, and decreased dependencies on upstream activators of pathways, such as CDK6. SuperDendrix also reveals dozens of dependencies on lineage-specific transcription factors, identifies cancer-type-specific correlations between dependencies, and enables annotation of individual mutated residues.

Using SuperDendrix, Park et al. examine associations between genetic dependencies in 769 cancer cell lines. They report 127 genetic dependencies explained by combinations of mutually exclusive somatic mutations congregating into a few oncogenic pathways across cancer subtypes. These present a small number of prominent and highly specific genetic vulnerabilities in cancer.

Graphical abstract

Oriented in situ immobilization of a functional tyrosinase on microcrystalline cellulose effectively incorporates DOPA residues in bioengineered mussel adhesive protein

BACKGROUND

Catechol-containing polymers such as mussel adhesive proteins (MAPs) are attractive as biocompatible adhesive biomaterials, and the catecholic amino acid 3,4-dihydroxyphenyl-L-alanine (DOPA) is considered a key molecule in underwater mussel adhesion. Tyrosinases can specifically convert tyrosine to DOPA without any cofactors. However, their catalytic properties still need to be adjusted to minimize unwanted DOPA oxidation via their diphenolase activity and catechol instability at neutral and basic pH values in the reaction products.

METHODS AND RESULTS

In this work, we constructed a novel functional tyrosinase, mTyr-CNK_CBM, by fusion of mTyr-CNK with a cellulose-binding motif (CBM) for oriented in situ immobilization on microcrystalline cellulose via the C-terminal CBM without any additional purification steps. mTyr-CNK_CBM showed optimal catalytic activity at pH 4.5-6.5 and room temperature and had a high monophenolase/diphenolase activity ratio (V_max mono/V_max di = 2.08 at pH 6 and 25°C). mTyr-CNK_CBM exhibited 2.17-fold higher (as a unimmobilized free enzyme) and similarly high (upon immobilization) in vitro DOPA modification of a bioengineered MAP compared to a commercially available mushroom tyrosinase. Moreover, the immobilized mTyr-CNK_CBM showed long-term storability and improved reusability.

CONCLUSIONS

These results clearly demonstrate a strong potential for practical use of immobilized mTyr-CNK_CBM as a monophenol monooxygenase in preparing biocompatible DOPA-tethered biomaterials and other catechol-containing polymers.

Sutureless Transplantation of Amniotic Membrane Using a Visible Light-Curable Protein Bioadhesive for Ocular Surface Reconstruction

The conjunctiva is a thin mucous membrane of the eye. Pterygium, a commonly appearing disease on the ocular surface, requires surgery to excise the conjunctiva to prevent visual deterioration. Recently, transplantation of the amniotic membrane (AM), which is the innermost membrane of the placenta, has been highlighted as an efficient method to cure conjunctiva defects because of its advantages of no side effects compared to mitomycin C treatment and not leaving additional scars on donor site compared to conjunctival autografting. However, to minimize additional damage to the ocular surface by suturing, AM transplantation (AMT) needs to be simplified by using a less invasive, time-saving method. In this work, a visible light-curable protein bioadhesive (named FixLight) for efficient sutureless AMT is applied. FixLight, which is based on bioengineered mussel adhesive protein (MAP), is easily applied between damaged ocular surfaces and transplanted AM, and rapidly cured by harmless blue light activation. Through in vivo evaluation using a rabbit model, the authors demonstrated that FixLight enabled facile, fast, and strong attachment of AM on sclera and promoted ocular surface reconstruction with good biocompatibility. Thus, FixLight can be successfully used as a promising clinical bioadhesive in opthalmological surgeries that require sutureless and rapid operation.

Preclinical evaluation of a regenerative immiscible bioglue for vesico-vaginal fistula

Currently, there are no clinically available tissue adhesives that work effectively in the fluid-rich and highly dynamic environments of the human body, such as the urinary system. This is especially relevant to the management of vesico-vaginal fistula, and developing a high-performance tissue adhesive for this purpose could vastly expand urologists' surgical repertoire and dramatically reduce patient discomfort. Herein, we developed a water-immiscible mussel protein-based bioadhesive (imWIMBA) with significantly improved properties in all clinical respects, allowing it to achieve rapid and strong underwater adhesion with tunable rheological properties. We evaluated in vivo potential of imWIMBA for sealing thermally injured fistula tracts between the bladder and vagina. Importantly, the use of imWIMBA in the presence of prolonged bladder drainage resulted in perfect closure of the vesico-vaginal fistula in operated pigs. Thus, imWIMBA could be successfully used for many surgical applications and improve treatment efficacy when combined with conventional surgical methods. STATEMENT OF SIGNIFICANCE: Vesico-vaginal fistula (VVF) is an abnormal opening between the bladder and the vagina, which is a stigmatized disease in many developing countries. Leakage of urine into internal organs can induce serious complications and delay wound repair. Conventional VVF treatment requires skillful suturing to provide a tension-free and watertight closure. In addition, there is no clinically approved surgical glue that works in wet and highly dynamic environments such as the urinary system. In this work, for potential clinical VVF closure and regeneration, we developed an advanced immiscible mussel protein-based bioglue with fast, strong, wet adhesion and tunable rheological properties. This regenerative immiscible bioglue could be successfully used for sealing fistulas and further diverse surgical applications as an adjuvant for conventional suture methods.

Adhesive protein-based angiogenesis-mimicking spatiotemporal sequential release of angiogenic factors for functional regenerative medicine

Damaged vascular structures after critical diseases are difficult to completely restore to their original conditions without specific treatments. Thus, therapeutic angiogenesis has been spotlighted as an attractive strategy. However, effective strategies for mimicking angiogenic processes in the body have not yet been developed. In the present work, we developed a bioengineered mussel adhesive protein (MAP)-based novel therapeutic angiogenesis platform capable of spatiotemporally releasing angiogenic growth factors to target disease sites with high viscosity and strong adhesiveness in a mucus-containing environment with curvature. Polycationic MAP formed complex coacervate liquid microdroplets with polyanionic hyaluronic acid and subsequently gelated into microparticles. Platelet-derived growth factor (PDGF), which is a late-phase angiogenic factor, was efficiently encapsulated during the process of coacervate microparticle formation. These PDGF-loaded microparticles were blended with vascular endothelial growth factor (VEGF), which is the initial-phase angiogenic factor, in MAP-based pregel solution and finally crosslinked in situ into a hydrogel at the desired site. The microparticle-based angiogenic-molecule spatiotemporal sequential (MASS) release platform showed good adhesion and underwater durability, and its elasticity was close to that of target tissue. Using two in vivo critical models, i.e., full-thickness excisional wound and myocardial infarction models, the MASS release platform was evaluated for its in vivo feasibility as an angiogenesis-inducing platform and demonstrated effective angiogenesis as well as functional regenerative efficacy. Based on these superior physicochemical characteristics, the developed MASS release platform could be successfully applied in many biomedical practices as a waterproof bioadhesive with the capability for the spatiotemporal delivery of angiogenic molecules in the treatment of ischemic diseases.

HALPER facilitates the identification of regulatory element orthologs across species

SUMMARY

Diverse traits have evolved through cis-regulatory changes in genome sequence that influence the magnitude, timing and cell type-specificity of gene expression. Advances in high-throughput sequencing and regulatory genomics have led to the identification of regulatory elements in individual species, but these genomic regions remain difficult to align across taxonomic orders due to their lack of sequence conservation relative to protein coding genes. The groundwork for tracing the evolution of regulatory elements is provided by the recent assembly of hundreds of genomes, the generation of reference-free Cactus multiple sequence alignments of these genomes, and the development of the halLiftover tool for mapping regions across these alignments. We present halLiftover Post-processing for the Evolution of Regulatory Elements (HALPER), a tool for constructing contiguous regulatory element orthologs from the outputs of halLiftover. We anticipate that this tool will enable users to efficiently identify orthologs of regulatory elements across hundreds of species, providing novel insights into the evolution of traits that have evolved through gene expression.

AVAILABILITY AND IMPLEMENTATION

HALPER is implemented in python and available on github: https://github.com/pfenninglab/halLiftover-postprocessing.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Hyperthermia associated with spinal radiculopathy as determined by digital infrared thermographic imaging

In general, in digital infrared thermographic imaging (DITI) of patients with unilateral spinal radicular pain, the thermal pattern of the extremities of the side of lesion shows hypothermia compared to the opposite, intact side. However, sometimes, DITI shows hyperthermia on the side of the lesion, and this variation can cause confusion. We compared the data of both hypothermia and hyperthermia patients to clarify the factors determining different thermal characteristics in spinal radiculopathy.We retrospectively collected data from patients who underwent DITI at a single center. The final cohort (n = 224) was allocated into 2 groups, a hypothermia group (n = 180) or a hyperthermia group (n = 44). We compared the various factors, including demographic factors and symptom-related factors, that might affect the results of DITI.Except the presence of trauma history (13.9% vs 31.8%, odds ratio 2.893, P = .008), no significant intergroup difference was found in baseline demographic factors, including age, gender, diabetes mellitus, spinal level of pathology, and intervention history. Among symptom-related factors, in the hyperthermia group, the symptom duration was shorter (10.64 weeks [95% confidence interval (CI) 8.36-13.04] vs 2.10 weeks [95% CI 1.05-3.53], P < .001) and Visual Analogue Scale (VAS) of radicular pain was higher (4.23 ± 1.29 vs 5.18 ± 1.40, P < .001) than in the hypothermia group. Also, in the regression analysis, significant factors for hyperthermia include the presence of trauma history, shorter symptom duration (cut-off value 2.50 weeks or less) and higher VAS of radicular pain (cut-off value 4.50 or more).In patients with trauma history, acute phase, and severe radicular pain, hyperthermia in DITI is not unusual and careful interpretation of the DITI results is necessary for proper diagnosis and treatment decisions in spinal radiculopathy.

Polysaccharide-Hydrophobic Nanoparticle Hybrid Nanoclusters for Enhanced Performance in Magnetic Resonance/Photoacoustic Imaging

Polysaccharide-nanoparticle (NP) hybrid nanoclusters have great potential to revitalize diverse bioapplications; however, fabricating polysaccharide-based hybrid nanoclusters composed of high-quality NPs generated in the organic phase remains a challenge. Here, using calcium alginate as a polysaccharide/tetramethylammonium hydroxide (TMAOH) combination, we report a novel approach to the design of alginate-hydrophobic magnetic-plasmonic core-shell (MPCS) NP hybrid nanoclusters (A-MPCS HNCs). Furthermore, we observe the dependence of the formation of A-MPCS HNCs on the TMAOH concentration. The enhanced performance in both magnetic resonance r₂ relaxivity and photoacoustic (PA) signals and the biocompatibility/bioactivity as well as the in vivo performance of A-MPCS HNCs shows them to be a promising magnetic resonance/photoacoustic dual-mode imaging agent. Our strategy could open doors to the use of other precious high-quality nanomaterials created in the organic phase via well-established synthetic chemistry in the design of alginate-hydrophobic nanomaterial hybrid nanoclusters, giving rise to novel and multifarious bioapplications.

Combinational Biomimicking of Lotus Leaf, Mussel, and Sandcastle Worm for Robust Superhydrophobic Surfaces with Biomedical Multifunctionality: Antithrombotic, Antibiofouling, and Tissue Closure Capabilities

Surface wetting occurring in daily life causes undesired contaminations, which are critical issues in various fields. To solve these problems, the nonwetting property of a superhydrophobic (SH) surface has proven its utility by preventing contaminant infiltration, serious infections, or malfunction. However, the application of SH surfaces in the biomedical field has been limited due to the weak durability and toxicity of the related components. To overcome these limitations, we developed a robust and biocompatible SH surface through combinational biomimicking of three natural organisms, lotus leaf, mussel, and sandcastle worm, for the first time. Using the water-immiscible and polycationic characteristics of mussel adhesive protein (iMglue), an SH iMglue-SiO₂(TiO₂/SiO₂)₂ coating was fabricated by solution-based electrical charge-controlled layer-by-layer growth of nanoparticles (NPs). The fabricated iMglue-SiO₂(TiO₂/SiO₂)₂ SH surface showed excellent durable nonwetting properties and was applied to an intracatheter tube coating to develop antithrombotic catheters under blood flow. Furthermore, we developed a iMglue-employed SH patch for a tissue closure bandage by spraying hydrophobic SiO₂ NPs on the iMglue-covered cotton pads. The prepared iMglue-employing SH patch showed perfect bifunctionality with excellent antibiofouling and tissue closure capabilities. Our work presents a novel, useful strategy for fabricating a biomedically multifunctional, robust SH surface through combinational mimicking of natural organisms.

Complex coacervates based on recombinant mussel adhesive proteins: their characterization and applications

Complex coacervates are a dense liquid phase of oppositely charged polyions formed by the associative separation of a mixture of polyions. Coacervates have been widely employed in many fields including the pharmaceutical, cosmetic, and food industries due to their intriguing interfacial and bulk material properties. More recently, attempts to develop an effective underwater adhesive have been made using complex coacervates that are based on recombinant mussel adhesive proteins (MAPs) due to the water immiscibility of complex coacervates and the adhesiveness of MAPs. MAP-based complex coacervates contribute to our understanding of the physical nature of complex coacervates and they provide a promising alternative to conventional invasive surgical repairs. Here, this review provides an overview of recombinant MAP-based complex coacervations, with an emphasis on their characterization and the uses of such materials for applications in the fields of biomedicine and tissue engineering.

Ginsenoside-Rp1 inhibits platelet activation and thrombus formation via impaired glycoprotein VI signalling pathway, tyrosine phosphorylation and MAPK activation

BACKGROUND AND PURPOSE

Ginsenosides are the main constituents for the pharmacological effects of Panax ginseng. Such effects of ginsenosides including cardioprotective and anti-platelet activities have shown stability and bioavailability limitations. However, information on the anti-platelet activity of ginsenoside-Rp1 (G-Rp1), a stable derivative of ginsenoside-Rg3, is scarce. We examined the ability of G-Rp1 to modulate agonist-induced platelet activation.

EXPERIMENTAL APPROACH

G-Rp1 in vitro and ex vivo effects on agonist-induced platelet-aggregation, granule-secretion, [Ca(2+) ](i) mobilization, integrin-α(IIb) β(3) activation were examined. Vasodilator-stimulated phosphoprotein (VASP) and MAPK expressions and levels of tyrosine phosphorylation of the glycoprotein VI (GPVI) signalling pathway components were also studied. G-Rp1 effects on arteriovenous shunt thrombus formation in rats or tail bleeding time and ex vivo coagulation time in mice were determined. KEY RESULT: G-Rp1 markedly inhibited platelet aggregation induced by collagen, thrombin or ADP. While G-Rp1 elevated cAMP levels, it dose-dependently suppressed collagen-induced ATP-release, thromboxane secretion, p-selectin expression, [Ca(2+) ](i) mobilization and α(IIb) β(3) activation and attenuated p38(MAPK) and ERK2 activation. Furthermore, G-Rp1 inhibited tyrosine phosphorylation of multiple components (Fyn, Lyn, Syk, LAT, PI3K and PLCγ2) of the GPVI signalling pathway. G-Rp1 inhibited in vivo thrombus formation and ex vivo platelet aggregation and ATP secretion without affecting tail bleeding time and coagulation time, respectively.

CONCLUSION AND IMPLICATIONS

G-Rp1 inhibits collagen-induced platelet activation and thrombus formation through modulation of early GPVI signalling events, and this effect involves VASP stimulation, and ERK2 and p38(-MAPK) inhibition. These data suggest that G-Rp1 may have therapeutic potential for the treatment of cardiovascular diseases involving aberrant platelet activation.

Formation of ZnO nanocones using wet chemical etching of ZnO nanorods in an aqueous solution of HCl

In this report, a simple wet chemical etching of ZnO nanorods to fabricate large area ZnO nanocones is demonstrated. The cone-like morphology formation utilizes anisotropic etching rate on the different crystal planes of ZnO nanorods in an aqueous solution of HCl (HCl [aq]). To form ZnO nanocones, single crystalline ZnO nanorods with a flat hexagonal shape are synthesized on p-Si(100) using hydrothermal method at 90 degrees C and then, are immersed in HCl [aq]. Electron microscopy reveals that the HCl [aq] treatment of ZnO nanorods significantly etched sidewalls of nanorods, resulting in the cone-like morphology formation. The nanocone formation is the most noticeable when the etching occurred in HCl [aq] with a pH of 2.5-3.0 for 5 min etching time. Geometrical analysis using the electron microscopy reveals that the sidewall of a ZnO nanocone have formed a plane indexed as (0-111) after the etching process.

Ginsenoside Rp1, a ginsenoside derivative, blocks lipopolysaccharide-induced interleukin-1beta production via suppression of the NF-kappaB pathway

Ginsenoside Rp1 (G-Rp1) is a ginseng saponin derivative with chemopreventive and anti-cancer activities. In this study, we examined the regulatory activity of G-Rp1 on the production of interleukin (IL)-1beta, a pro-inflammatory cytokine managing acute or chronic inflammatory diseases such as septic shock and rheumatoid arthritis, from lipopolysaccharide (LPS)-treated macrophage-like RAW264.7 cells. G-Rp1 dose-dependently inhibited IL-1beta production from LPS-treated RAW264.7 cells without altering cell viability. This compound suppressed both mRNA and protein levels of IL-1beta. In particular, this compound was found to down-regulate phosphorylation of the inhibitor of kappaB (IkappaB) kinase (IKK)/IkappaBalpha, and consequent activation of NF-kappaB, but not the activation of its upstream signaling enzymes such as mitogen-activated protein kinases (MAPK) and p85, a regulatory subunit of phosphoinositide 3-kinase (PI3K). Therefore, these results suggest that G-Rp1 may act as an inhibitor of IL-1beta production by inhibiting the NF-kappaB pathway.

Anti-metastatic potential of ginsenoside Rp1, a novel ginsenoside derivative

Ginsenoside Rp1 (G-Rp1) is a novel ginseng saponin with a chemopreventive action. In this study, we examined the anti-metastatic activities of G-Rp1 using relevant in vitro assays and in vivo metastasis models. Using a U937 cell-cell adhesion assay, we found that exogenously added G-Rp1 down-regulates beta1-integrin (CD29) activation at concentrations between 10 to 40 microM and suppresses the in vitro tube formation of human umbilical vein endothelial cells (HUVECs). Furthermore, this compound directly blocked cell viability of cancer cells such as A549 and HCT15 cells. In agreement with in vitro findings, G-Rp1 strongly inhibited the metastatic lung transfer of B16-F10 melanoma cells, which have a high surface level of beta1-integrins, without altering body weight. Therefore, these results suggest that G-Rp1 may act as an anti-cancer agent by strongly inhibiting cell viability and metastatic processes, presumably by inhibiting the adhesion of tumor cells and vessel formation.

The PPLA motif of glycogen synthase kinase 3beta is required for interaction with Fe65

Glycogen synthase kinase 3beta (GSK 3 beta) is a serine/ threonine kinase that phosphorylates substrates such as beta-catenin and is involved in a variety of biological processes, including embryonic development, metabolism, tumorigenesis, and cell death. Here, we present evidence that human GSK 3beta is associated with Fe65, which has the characteristics of an adaptor protein, possessing a WW domain, and two phosphotyrosine interaction domains, PID1 and PID2. The GSK 3beta catalytic domain also contains a putative WW domain binding motif ((371)PPLA(374)), and we observed, using a pull down approach and co-immuno-precipitation, that it interacts physically with Fe65 via this motif. In addition, we detected co-localization of GSK 3beta and Fe65 by confocal microscopy, and this co-localization was disrupted by mutation of the putative WW domain binding motif of GSK 3beta.Finally, in transient transfection assays interaction of GSK 3 beta (wt) with Fe65 induced substantial cell apoptosis, whereas interaction with the GSK 3beta AALA mutant ((371)AALA(374)) did not, and we noted that phosphorylation of the Tyr 216 residue of the GSK 3beta AALA mutant was significantly reduced compared to that of GSK 3beta wild type. Thus, our observations indicate that GSK 3beta binds to Fe65 through its (371)PPLA(374) motif and that this interaction regulates apoptosis and phosphorylation of Tyr 216 of GSK 3beta.

Modifications of aliphatic side chain of 20(S)-ginsenoside RG3 cause an enhancement or loss of brain Na+ channel current inhibitions

A line of evidence has shown that ginsenoside Rg3 (Rg3) could be one of bioactive ligands in brain Na+ channel regulations. Rg3 exists as stereoisomer of 20(R)- or 20(S)-form. Rg3 consists of three different parts; steroid- like backbone structure, carbohydrate portion, and aliphatic side chain [-CH2CH2CH=C(CH3)2], which is coupled to the carbon-20 of backbone structure. In the previous report, we demonstrated that 20(S)- but not 20(R)-Rg3 and carbohydrate portion of Rg3 play important roles in rat brain NaV1.2 channel regulations. However, little is known about the role of aliphatic side chain coupled to the carbon-20 in brain Na+ channel regulations. In the present study, we prepared Rg3 derivatives by modifying the aliphatic side chain of Rg3, remaining with backbone structure and carbohydrate portion intact, and examined the effects of Rg3 derivatives on Na+ channel activity. We found that reduction of double bond in aliphatic side chain of Rg3 exhibited agonistic actions in Na+ channel current inhibitions by shifting concentration-response curve to leftward by three-fold, whereas deletion, hydroxylation, or oxygenation of aliphatic side chain caused an attenuation or loss of Na+ channel current inhibitions. These results provide evidences that the aliphatic side chain of Rg3 is also involved in Na+ channel regulations and further show a possibility that the aliphatic side chain of Rg3 could be the target of chemical modifications for abolishment or potentiation of Rg3 actions in Na+ channel regulations.

Genetic diversity and mating system of the threatened plant Kirengeshoma palmata (Saxifragaceae) in Korea

The endangered herb Kirengeshoma palmata, from eastern Asia, has had its population severely reduced in number through habitat loss and fragmentation. All of the individuals within five subgroups at Mt. Baek-un-san, in the southern part of Korea, were genetically surveyed by allozyme analysis. Genetic diversity levels within subgroups were relatively high, and a consistently high outcrossing rate as well as a negligible biparental mating rate were confirmed by this study. Several groups of visibly connected ramets were observed in a clustered distribution which suggested cloning. Absence of mating partner rather than pollinators decreased seed production in small mating groups. The present genetic structure of the five subgroups was probably the result of local extinction of intervening populations. Because K. palmata may be a self-incompatible species, populations with few genets face lowered seed set due to mate scarcity. Thus, this type of population may be at an increased risk of extinction as a result of inbreeding depression, loss of genetic variability, and reduced sexual reproduction. The small, genetically depauperate subgroups may need an input of seeds or plants from other populations in China or Japan in order to regenerate, but the possibility of outcrossing depression leads us to recommend outbreeding among the local subgroups of Mt. Baek-un-san to restore genetic variability.

Heat shock protein 60 modified withO-linkedN-acetylglucosamine is involved in pancreatic β-cell death under hyperglycemic conditions

The objective of this study was to identify proteins modified with O-linked N-acetylglucosamine (O-GlcNAc) in pancreatic beta-cells and to understand their roles in cell death under hyperglycemic conditions. Here we report that heat shock protein 60 (HSP60) is modified with O-GlcNAc. Levels of O-GlcNAcylated HSP60 increased twofold in response to hyperglycemic conditions. HSP60 is a chaperonin known to bind to Bax in the cytoplasm under normoglycemic conditions. Under hyperglycemic conditions, Bax detached from O-GlcNAcylated HSP60 and translocated to mitochondria. Hyperglycemic conditions were also associated with cytochrome c release, caspase-3 activation, and cell death, suggesting that elevated O-GlcNAcylation of HSP60 interferes with HSP60-Bax interactions, leading to pancreatic beta-cell death.

Evaluation of chemopreventive action of Ginsenoside Rp1

We evaluated the chemopreventive properties of Ginsenoside Rp1 on 7,12-Dimethyl benz (a) anthracene (DMBA) skin papillomagenesis in Swiss albino mice. A significant reduction in values of tumor incidence, tumor burden, and cumulative number of papilloma was observed in mice treated orally with Ginsenoside Rp1 continuously at pre-, peri- and post-initiational stages of papillomagenesis as compared to the control group. Chemopreventive potential of Ginsenoside Rp1 was also observed on the skin metabolizing enzymes in Swiss albino mice. Ginsenoside Rp1 produced a significant elevation in the skin microsomal cytochrome p-450 and cytochrome b5, glutathione S-transferase (GST), reduced glutathione (GSH), glutathione peroxidase (GPX), glutathione reductase (GR), DT-diaphorase, superoxide dismutase (SOD) and catalase levels in the group of mice treated with Ginsenoside Rp1 for seven consecutive days. However, there was significant decrease in lipid peroxidation (LPO) level in Ginsenoside Rp1 treated group.