Mapping the emergence of molecular vibrations mediating bond formation.

Fundamental studies of chemical reactions often consider the molecular dynamics along a reaction coordinate using a calculated or suggested potential energy surface1-5. But fully mapping such dynamics experimentally, by following all nuclear motions in a time-resolved manner-that is, the motions of wavepackets-is challenging and has not yet been realized even for the simple stereotypical bimolecular reaction6-8: A-B + C â†’ A + B-C. Here we track the trajectories of these vibrational wavepackets during photoinduced bond formation of the gold trimer complex [Au(CN)2-]3 in an aqueous monomer solution, using femtosecond X-ray liquidography9-12 with X-ray free-electron lasers13,14. In the complex, which forms when three monomers A, B and C cluster together through non-covalent interactions15,16, the distance between A and B is shorter than that between B and C. Tracking the wavepacket in three-dimensional nuclear coordinates reveals that within the first 60 femtoseconds after photoexcitation, a covalent bond forms between A and B to give A-B + C. The second covalent bond, between B and C, subsequently forms within 360 femtoseconds to give a linear and covalently bonded trimer complex A-B-C. The trimer exhibits harmonic vibrations that we map and unambiguously assign to specific normal modes using only the experimental data. In principle, more intense X-rays could visualize the motion not only of highly scattering atoms such as gold but also of lighter atoms such as carbon and nitrogen, which will open the door to the direct tracking of the atomic motions involved in many chemical reactions.

Ultrafast Optically Induced Perturbation of Oxygen Octahedral Rotations in Multiferroic BiFeO3 Thin Films.

The functional properties of complex oxides, including magnetism and ferroelectricity, are closely linked to subtle structural distortions. Ultrafast optical excitations provide the means to manipulate structural features and ultimately to affect the functional properties of complex oxides with picosecond-scale precision. We report that the lattice expansion of multiferroic BiFeO3 following above-bandgap optical excitation leads to distortion of the oxygen octahedral rotation (OOR) pattern. The continuous coupling between OOR and strain was probed using time-resolved X-ray free-electron laser diffraction with femtosecond time resolution. Density functional theory calculations predict a relationship between the OOR and the elastic strain consistent with the experiment, demonstrating a route to employing this approach in a wider range of systems. Ultrafast control of the functional properties of BiFeO3 thin films is enabled by this approach because the OOR phenomena are related to ferroelectricity, and via the Fe-O-Fe bond angles, the superexchange interaction between Fe atoms.

Iridoid Glycosides and Coumarin Glycoside Derivatives from the Roots of Nymphoides peltata and Their In Vitro Wound Healing Properties.

Nymphoides peltata has been used as a medicinal herb in traditional medicines to treat strangury, polyuria, and swelling. The phytochemical investigation of the MeOH extract of N. peltata roots led to the isolation of three iridoid glycosides and three coumarin glycoside derivatives, which were characterized as menthiafolin (1), threoninosecologanin (2), callicoside C (3), and scopolin (4), as well as two undescribed peltatamarins A (5) and B (6). The chemical structures of the undescribed compounds were determined by analyzing their 1 dimensional (D) and 2D nuclear magnetic resonance (NMR) spectra and using high-resolution (HR)-electrospray ionization mass spectroscopy (ESI-MS), along with the chemical reaction of acid hydrolysis. The wound healing activities of the isolated compounds 1-6 were evaluated using a HaCaT cell scratch test. Among the isolates, scopolin (4) and peltatamarin A (5) promoted HaCaT cell migration over scratch wounds, and compound 5 was the most effective. Furthermore, compound 5 significantly promoted cell migration without adversely affecting cell proliferation, even when treated at a high dose (100 µM). Our results demonstrate that peltatamarin A (5), isolated from N. peltata roots, has the potential for wound healing effects.

Anti-Allergic Inflammatory Effect of Agarum cribrosum and Its Phlorotannin Component, Trifuhalol A, against the Ovalbumin-Induced Allergic Asthma Model.

Asthma is a chronic inflammatory disease involving structural changes to the respiratory system and severe immune responses mediated by allergic cytokines and pro-inflammatory mediators. Agarum cribrosum (AC) is a kind of seaweed which contains a phlorotannin, trifuhalol A. To evaluate its anti-allergic inflammatory effect against asthma, an ovalbumin inhalation-induced mouse asthma model was used. Histologic observations proved that trifuhalol A is minimizing the lung and tracheal structure changes as well as the infiltration of eosinophils and mast cells against ovalbumin inhalation challenge. From the serum and bronchoalveolar lavage fluid, ovalbumin-specific IgE and Th2-specific cytokines, IL-4, -5, and -13, were reduced with trifuhalol A treatment. In addition, IL-1ß, IL-6, and TNF-α concentrations in lung homogenate were also significantly reduced via trifuhalol A treatment. Taken together, trifuhalol A, isolated from AC, was able to protect lung and airways from Th2-specific cytokine release, and IgE mediated allergic inflammation as well as the attenuation of IL-1ß, IL-6, and TNF-α in lung, which results in the suppression of eosinophils and the mast cells involved asthmatic pathology.

Subpicosecond Optical Stress Generation in Multiferroic BiFeO3.

Optical excitation leads to ultrafast stress generation in the prototypical multiferroic BiFeO3. The time scales of stress generation are set by the dynamics of the population of excited electronic states and the coupling of the electronic configuration to the structure. X-ray free-electron laser diffraction reveals high-wavevector subpicosecond-time scale stress generation following ultraviolet excitation of a BiFeO3 thin film. Stress generation includes a fast component with a 1/e rise time with an upper limit of 300 fs and longer-rise time components extending to 1.5 ps. The contributions of the fast and delayed components vary as a function of optical fluence, with a reduced a fast-component contribution at high fluence. The results provide insight into stress-generation mechanisms linked to the population of excited electrons and point to new directions in the application of nanoscale multiferroics and related ferroic complex oxides. The fast component of the stress indicates that structural parameters and properties of ferroelectric thin film materials can be optically modulated with 3 dB bandwidths of at least 0.5 THz.

Ultrafast Carrier-Lattice Interactions and Interlayer Modulations of Bi2Se3 by X-ray Free-Electron Laser Diffraction.

As a 3D topological insulator, bismuth selenide (Bi2Se3) has potential applications for electrically and optically controllable magnetic and optoelectronic devices. Understanding the coupling with its topological phase requires studying the interactions of carriers with the lattice on time scales down to the subpicosecond regime. Here, we investigate the ultrafast carrier-induced lattice contractions and interlayer modulations in Bi2Se3 thin films by time-resolved diffraction using an X-ray free-electron laser. The lattice contraction depends on the carrier concentration and is followed by an interlayer expansion accompanied by oscillations. Using density functional theory and the Lifshitz model, the initial contraction can be explained by van der Waals force modulation of the confined free carrier layers. Our theoretical calculations suggest that the band inversion, related to a topological phase transition, is modulated by the expansion of the interlayer distance. These results provide insights into the topological phase control by light-induced structural change on ultrafast time scales.

Lobelia chinensis Extract and Its Active Compound, Diosmetin, Improve Atopic Dermatitis by Reinforcing Skin Barrier Function through SPINK5/LEKTI Regulation.

The skin acts as a mechanical barrier that protects the body from the exterior environment, and skin barrier function is attributed to the stratum corneum (SC), which is composed of keratinocytes and skin lipids. Skin barrier homeostasis is maintained by a delicate balance between the differentiation and exfoliation of keratinocytes, and keratinocyte desquamation is regulated by members of the serine protease kalikrein (KLK) family and their endogenous inhibitor SPINK5/LEKTI (serine protease inhibitor Kazal type 5/lympho-epithelial Kazal-type-related inhibitor). Furthermore, SPINK5/LEKTI deficiency is involved in impaired skin barrier function caused by KLK over-activation. We sought to determine whether increased SPINK5/LEKTI expression ameliorates atopic dermatitis (AD) by strengthening skin barrier function using the ethanol extract of Lobelia chinensis (LCE) and its active compound, diosmetin, by treating human keratinocytes with UVB and using a DNCB-induced murine model of atopic dermatitis. LCE or diosmetin dose-dependently increased the transcriptional activation of SPINK5 promoter and prevented DNCB-induced skin barrier damage by modulating events downstream of SPINK5, that is, KLK, PAR2 (protease activated receptor 2), and TSLP (thymic stromal lymphopoietin). LCE or diosmetin normalized immune response in DNCB treated SKH-1 hairless mice as determined by reductions in serum immunoglobulin E and interleukin-4 levels and numbers of lesion-infiltrating mast cells. Our results suggest that LCE and diosmetin are good candidates for the treatment of skin barrier-disrupting diseases such as Netherton syndrome or AD, and that they do so by regulating SPINK5/LEKTI.

PRMT7 Inhibitor SGC8158 Enhances Doxorubicin-Induced DNA Damage and Its Cytotoxicity.

Protein arginine methyltransferase 7 (PRMT7) regulates various cellular responses, including gene expression, cell migration, stress responses, and stemness. In this study, we investigated the biological role of PRMT7 in cell cycle progression and DNA damage response (DDR) by inhibiting PRMT7 activity with either SGC8158 treatment or its specific siRNA transfection. Suppression of PRMT7 caused cell cycle arrest at the G1 phase, resulting from the stabilization and subsequent accumulation of p21 protein. In addition, PRMT7 activity is closely associated with DNA repair pathways, including both homologous recombination and non-homologous end-joining. Interestingly, SGC8158, in combination with doxorubicin, led to a synergistic increase in both DNA damage and cytotoxicity in MCF7 cells. Taken together, our data demonstrate that PRMT7 is a critical modulator of cell growth and DDR, indicating that it is a promising target for cancer treatment.

Trifuhalol A Suppresses Allergic Inflammation through Dual Inhibition of TAK1 and MK2 Mediated by IgE and IL-33.

The activation and degranulation of immune cells play a pivotal role in allergic inflammation, a pathological condition that includes anaphylaxis, pruritus, and allergic march-related diseases. In this study, trifuhalol A, a phlorotannin isolated from Agarum cribrosum, inhibited the degranulation of immune cells and the biosynthesis of IL-33 and IgE in differentiated B cells and keratinocytes, respectively. Additionally, trifuhalol A suppressed the IL-33 and IgE-mediated activation of RBL-2H3 cells through the regulation of the TAK1 and MK2 pathways. Hence, the effect of trifuhalol A on allergic inflammation was evaluated using a Compound 48/80-induced systemic anaphylaxis mouse model and a house dust mite (HDM)-induced atopic dermatitis (AD) mouse model. Trifuhalol A alleviated anaphylactic death and pruritus, which appeared as an early-phase reaction to allergic inflammation in the Compound 48/80-induced systemic anaphylaxis model. In addition, trifuhalol A improved symptoms such as itching, edema, erythema, and hyperkeratinization in HDM-induced AD mice as a late-phase reaction. Moreover, the expression of IL-33 and thymic stromal lymphopoietin, inflammatory cytokines secreted from activated keratinocytes, was significantly reduced by trifuhalol A administration, resulting in the reduced infiltration of immune cells into the skin and a reduction in the blood levels of IgE and IL-4. In summarizing the above results, these results confirm that trifuhalol A is a potential therapeutic candidate for the regulation of allergic inflammation.

Estrogenic activity of ethyl gallate and its potential use in hormone replacement therapy.

We aimed to compare the estrogenic activities of compounds isolated from Moutan Cortex Radicis (MRC, Paeonia suffruticosa Andrews) and identify their potential use in hormone replacement therapy. We quantified seven marker components (gallic acid, oxypaeoniflorin, paeoniflorin, ethyl gallate, benzoic acid, benzoylpaeoniflorin, and paeonol) in MRC using a high-performance liquid chromatography simultaneous analysis assay. To investigate the estrogenic activity of MRC and the seven marker components, an E-screen assay was conducted using the estrogen receptor (ER)-positive MCF-7 human breast cancer cell line. Among them, ethyl gallate caused cell proliferation in a concentration-dependent manner at concentrations above 25 µM and was clearly suppressed by combination treatment with the ER antagonist ICI 182,780. Therefore, ethyl gallate may be a compound of MRC that can increase the estrogenic effect in ER-positive MCF-7 cells.

Wikstroemiaganpi Extract Improved Atopic Dermatitis-Like Skin Lesions via Suppression of Interleukin-4 in 2,4-Dinitrochlorobenzene-Induced SKH-1 Hairless Mice.

Plants of the genus Wikstroemia are used in Chinese traditional medicine to treat inflammatory diseases, such as arthritis, bronchitis, and pneumonia. The present study was designed to determine whether Wikstroemia ganpi (Siebold and Zucc.) Maxim. offers a potential means of treating 2,4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis (AD) in mice. Symptoms such as redness, edema, and keratinization in AD mice induced by DNCB were alleviated by the co-application of an ethanolic extract of W. ganpi for 2 weeks. The severity of skin barrier function damage was evaluated by measuring TEWL (transepidermal water loss). TEWLs of DNCB sensitized mouse dorsal skin were reduced by the application of a W. ganpi ethanolic extract, and skin hydration was increased. In addition, the infiltration of inflammatory cells into the dermis was significantly reduced, as were blood levels of IgE and IL-4, which play an important role in the expression of AD. The results of this experiment suggest that W. ganpi is a potential therapeutic agent for AD.

PPARß/δ agonist GW501516 inhibits TNFα-induced repression of adiponectin and insulin receptor in 3T3-L1 adipocytes.

Previous reports have shown that PPARß/δ agonists ameliorate insulin resistance associated with type 2 diabetes mellitus (T2DM). To determine the role of PPARß/δ in tumor necrosis factor α (TNFα)-mediated insulin resistance, we investigated expression levels of adiponectin and insulin receptor (IR) in response to treatment with the PPARß/δ agonist GW501516 with or without TNFα, a proinflammatory cytokine, in differentiated 3T3-L1 adipocytes. GW501516 induced adipocyte differentiation and the expression of adiponectin in a dose-dependent manner in differentiated adipocytes. TNFα treatment reduced adiponectin expression at the end of differentiation. This effect was reversed by GW501516 co-treatment with TNFα. TNFα treatment decreased adipogenic marker genes such as PPARγ, aP2, resistin, and GLUT4, and GW501516 reversed the effects of TNFα. GW501516 treatment increased the expression of insulin receptor and inhibited TNFα-mediated repression of insulin receptor. Our results showed that GW501516 abrogated TNFα-induced insulin resistance. In summary, our study demonstrated that the PPARß/δ agonist, GW501516 reversed TNFα-induced decreases in adipocyte differentiation and adiponectin expression, and improved insulin sensitivity by increasing the expression of insulin receptor. Therefore, PPARδ may be a promising therapeutic target for treatment of insulin resistance in patients with T2DM.

Hard X-ray self-seeding commissioning at PAL-XFEL.

A wake monochromator based on a large-area diamond single crystal for hard X-ray self-seeding has been successfully installed and commissioned in the hard X-ray free-electron laser (FEL) at the Pohang Accelerator Laboratory with international collaboration. For this commissioning, the self-seeding was demonstrated with a low bunch charge (40 pC) and the nominal bunch charge (180 pC) of self-amplified spontaneous emission (SASE) operation. The FEL pulse lengths were estimated as 7 fs and 29.5 fs, respectively. In both cases, the average spectral brightness increased by more than three times compared with the SASE mode. The self-seeding experiment was demonstrated for the first time using a crystal with a thickness of 30 µm, and a narrow bandwidth of 0.22 eV (full width at half-maximum) was obtained at 8.3 keV, which confirmed the functionality of a crystal with such a small thickness. In the nominal bunch-charge self-seeding experiment, the histogram of the intensity integrated over a 1 eV bandwidth showed a well defined Gaussian profile, which is evidence of the saturated FEL and a minimal electron-energy jitter (∼1.2 × 10-4) effect. The corresponding low photon-energy jitter (∼2.4 × 10-4) of the SASE FEL pulse, which is two times lower than the Pierce parameter, enabled the seeding power to be maximized by maintaining the spectral overlap between SASE FEL gain and the monochromator.

Comparing the spatial coherence of the natural and focused X-rays from a free electron laser.

The degree of spatial coherence, as basic characteristics of the radiation, becomes an important guide to evaluate the performance of X-rays from newly introduced advanced light sources including the X-ray free electron laser (XFEL). Often the modification of the X-ray wavefronts to fulfill various applications is necessary, but also there is the need to preserve its coherence property. However, experimental investigation directly comparing the coherence property of focused X-ray radiations with the unmodified ones has not been available. We have performed Young's double-slit experiments by recording diffraction patterns both from slit apertures for unfocused XFEL radiation and from pairs of Au nanoparticles for one-micron focused XFEL radiations. The results confirm that the degree of spatial coherence is preserved for well-built K-B focusing mirrors.

Stellera chamaejasme and Its Main Compound Luteolin 7-O-Glucoside Alleviates Skin Lesions in Oxazolone- and 2,4-Dinitrochlorobenzene-Stimulated Murine Models of Atopic Dermatitis.

Stellera chamaejasme, also known as "Langdu", has been traditionally used for the management of skin-related diseases such as psoriasis and skin ulcers. The aim of this study was to determine whether S. chamaejasme and its major component, luteolin 7-O-glucoside, have a preventive effect on the development of atopic dermatitis in oxazolone-treated BALB/c mice and 2,4-dinitrochlorobenzene-treated hairless mice. The epicutaneous applications of oxazolone and 2,4-dinitrochlorobenzene evoke an experimental murine atopic dermatitis-like reaction in BALB/c mouse ears and SKH-1 hairless mice. Atopic skin symptoms, including erythema (redness), pruritus (itching), exudation (weeping), excoriation (peeling), and lichenification (skin thickening), responded to treatment with S. chamaejasme aerial parts EtOH extract for 2 or 3 weeks. Histopathological examination revealed S. chamaejasme aerial parts EtOH extract significantly reduced inflammatory cell infiltration when applied to atopic dermatitis mice. In addition, luteolin 7-O-glucoside, the major active compound of the S. chamaejasme aerial parts EtOH extract, decreased serum IgE and IL-4 levels and transepidermal water loss and increased skin hydration, therefore exhibiting strong anti-atopic dermatitis activity in 2,4-dinitrochlorobenzene-induced atopic dermatitis mice. In this study, we confirmed antipruritic and antidermatitic effects of S. chamaejasme extract and its main component luteolin 7-O-glucoside in atopic dermatitis murine models. The study shows S. chamaejasme aerial parts EtOH extract and luteolin 7-O-glucoside are most likely to be potential drug candidates for atopic dermatitis treatment.

Neuroprotective Effects of Tetrahydrocurcumin against Glutamate-Induced Oxidative Stress in Hippocampal HT22 Cells.

In the central nervous system, glutamate is a major excitable neurotransmitter responsible for many cellular functions. However, excessive levels of glutamate induce neuronal cell death via oxidative stress during acute brain injuries as well as chronic neurodegenerative diseases. The present study was conducted to examine the effect of tetrahydrocurcumin (THC), a major secondary metabolite of curcumin, and its possible mechanism against glutamate-induced cell death. We prepared THC using curcumin isolated from Curcuma longa (turmeric) and demonstrated the protective effect of THC against glutamate-induced oxidative stress in HT22 cells. THC abrogated glutamate-induced HT22 cell death and showed a strong antioxidant effect. THC also significantly reduced intracellular calcium ion increased by glutamate. Additionally, THC significantly reduced the accumulation of intracellular oxidative stress induced by glutamate. Furthermore, THC significantly diminished apoptotic cell death indicated by annexin V-positive in HT22 cells. Western blot analysis indicated that the phosphorylation of mitogen-activated protein kinases including c-Jun N-terminal kinase, extracellular signal-related kinases 1/2, and p38 by glutamate was significantly diminished by treatment with THC. In conclusion, THC is a potent neuroprotectant against glutamate-induced neuronal cell death by inhibiting the accumulation of oxidative stress and phosphorylation of mitogen-activated protein kinases.

Acute ethanol exposure-induced autophagy-mediated cardiac injury via activation of the ROS-JNK-Bcl-2 pathway.

Binge drinking is associated with increased cardiac autophagy, and often triggers heart injury. Given the essential role of autophagy in various cardiac diseases, this study was designed to investigate the role of autophagy in ethanol-induced cardiac injury and the underlying mechanism. Our study showed that ethanol exposure enhanced the levels of LC3-II and LC3-II positive puncta and promoted cardiomyocyte apoptosis in vivo and in vitro. In addition, we found that ethanol induced autophagy and cardiac injury largely via the sequential triggering of reactive oxygen species (ROS) accumulation, activation of c-Jun NH2-terminal kinase (JNK), phosphorylation of Bcl-2, and dissociation of the Beclin 1/Bcl-2 complex. By contrast, inhibition of ethanol-induced autophagic flux with pharmacologic agents in the hearts of mice and cultured cells significantly alleviated ethanol-induced cardiomyocyte apoptosis and heart injury. Elimination of ROS with the antioxidant N-acetyl cysteine (NAC) or inhibition of JNK with the JNK inhibitor SP600125 reduced ethanol-induced autophagy and subsequent autophagy-mediated apoptosis. Moreover, metallothionein (MT), which can scavenge reactive oxygen and nitrogen species, also attenuated ethanol-induced autophagy and cell apoptosis in MT-TG mice. In conclusion, our findings suggest that acute ethanol exposure induced autophagy-mediated heart toxicity and injury mainly through the ROS-JNK-Bcl-2 signaling pathway.

Eupatilin, an activator of PPARα, inhibits the development of oxazolone-induced atopic dermatitis symptoms in Balb/c mice.

Eupatilin (5,7-dihydroxy-3',4',6-trimethoxyflavone) is the main lipophilic flavonoid obtained from the Artemisia species. Eupatilin has been reported to have anti-apoptotic, anti-oxidative and anti-inflammatory activities. Previously, we found that eupatilin increases transcriptional activity and expression of peroxisome proliferator-activated receptor α (PPARα) in a keratinocyte cell line and acts as an agonist of PPARα. PPARα agonists ameliorate atopic dermatitis (AD) and restore the skin barrier function. In this study, we confirmed that the effects of eupatilin improved AD-like symptoms in an oxazolone-induced AD-like mouse model. Furthermore, we found that eupatilin suppressed the levels of serum immunoglobulin E (IgE), interleukin-4 (IL-4), and AD involved cytokines, such as tumor necrosis factor α (TNFα), interferon-γ (IFN-γ), IL-1ß, and thymic stromal lymphopoietin (TSLP), IL-33, IL-25 and increased the levels of filaggrin and loricrin in the oxazolone-induced AD-like mouse model. Taken together, our data suggest that eupatilin is a potential candidate for the treatment of AD.

Focusing X-ray free-electron laser pulses using Kirkpatrick-Baez mirrors at the NCI hutch of the PAL-XFEL.

The Pohang Accelerator Laboratory X-ray Free-Electron Laser (PAL-XFEL) is a recently commissioned X-ray free-electron laser (XFEL) facility that provides intense ultrashort X-ray pulses based on the self-amplified spontaneous emission process. The nano-crystallography and coherent imaging (NCI) hutch with forward-scattering geometry is located at the hard X-ray beamline of the PAL-XFEL and provides opportunities to perform serial femtosecond crystallography and coherent X-ray diffraction imaging. To produce intense high-density XFEL pulses at the interaction positions between the X-rays and various samples, a microfocusing Kirkpatrick-Baez (KB) mirror system that includes an ultra-precision manipulator has been developed. In this paper, the design of a KB mirror system that focuses the hard XFEL beam onto a fixed sample point of the NCI hutch, which is positioned along the hard XFEL beamline, is described. The focusing system produces a two-dimensional focusing beam at approximately 2 µm scale across the 2-11 keV photon energy range. XFEL pulses of 9.7 keV energy were successfully focused onto an area of size 1.94 µm × 2.08 µm FWHM.