Discovery of a small-molecule inhibitor of the TRIP8b-HCN interaction with efficacy in neurons.

Major depressive disorder is a critical public health problem with a lifetime prevalence of nearly 17% in the United States. One potential therapeutic target is the interaction between hyperpolarization-activated cyclic nucleotide-gated (HCN) channels and an auxiliary subunit of the channel named tetratricopeptide repeat-containing Rab8b-interacting protein (TRIP8b). HCN channels regulate neuronal excitability in the mammalian hippocampus, and recent work has established that antagonizing HCN function rescues cognitive impairment caused by chronic stress. Here, we utilize a high-throughput virtual screen to find small molecules capable of disrupting the TRIP8b-HCN interaction. We found that the hit compound NUCC-0200590 disrupts the TRIP8b-HCN interaction in vitro and in vivo. These results provide a compelling strategy for developing new small molecules capable of disrupting the TRIP8b-HCN interaction.

HCN channels and absence seizures.

Hyperpolarization-activation cyclic nucleotide-gated (HCN) channels were for the first time implicated in absence seizures (ASs) when an abnormal Ih (the current generated by these channels) was reported in neocortical layer 5 neurons of a mouse model. Genetic studies of large cohorts of children with Childhood Absence Epilepsy (where ASs are the only clinical symptom) have identified only 3 variants in HCN1 (one of the genes that code for the 4 HCN channel isoforms, HCN1-4), with one (R590Q) mutation leading to loss-of-function. Due to the multi-faceted effects that HCN channels exert on cellular excitability and neuronal network dynamics as well as their modulation by environmental factors, it has been difficult to identify the detailed mechanism by which different HCN isoforms modulate ASs. In this review, we systematically and critically analyze evidence from established AS models and normal non-epileptic animals with area- and time-selective ablation of HCN1, HCN2 and HCN4. Notably, whereas knockout of rat HCN1 and mouse HCN2 leads to the expression of ASs, the pharmacological block of all HCN channel isoforms abolishes genetically determined ASs. These seemingly contradictory results could be reconciled by taking into account the well-known opposite effects of Ih on cellular excitability and network function. Whereas existing evidence from mouse and rat AS models indicates that pan-HCN blockers may provide a novel approach for the treatment of human ASs, the development of HCN isoform-selective drugs would greatly contribute to current research on the role for these channels in ASs generation and maintenance as well as offer new potential clinical applications.

Ultrathin 2D Cerium-Based Metal-Organic Framework Nanosheet That Boosts Selective Oxidation of Inert C(sp3 )H Bond through Multiphoton Excitation.

The development of methodologies for inducing and tailoring activities of catalysts is an important issue in various catalysis. The ultrathin 2D monolayer metal-organic framework (MOF) nanosheets with more accessible active sites and faster diffusion obtained by exfoliating 3D layered MOFs are of great potential as heterogeneous catalysts, but the rational design and preparation of 3D layered MOFs remains a grand challenge. Herein, a novel weak electrostatic interaction strategy to construct a 3D layered cerium-bearing MOF by coordinating chlorine-capped cerium nodes and linear photoactive methyl viologen (MV+ ) organic linkers is used. Under multiphoton excitation, the MV+ ligands and CeCl chromophores are triggered consecutively to form the high activity chlorine radical (Cl• ) for activation of inert C(sp3 )H bond through a hydrogen atom transfer. Benefiting from framework confinement effects, synergistic effects of two active sites and/or flexibility of the ultrathin framework nanosheets with high surface utilization, the observed activities increase in the order CeCl3 /MV+  < bulk 3D MOF crystals < 2D MOF nanosheets in photocatalysis. This work not only contributes a new strategy to construct 3D layered MOFs and their ultrathin nanosheets but also paves the way to use nanostructured MOFs to handle synergy of multiple molecular catalysts.

Luminescence Studies on Dy3+ Doped Calcium Aluminum Borosilicate (CABS) Glasses for White Light Emission and Applications in w-LEDs.

Dy3+ doped calcium aluminum borosilicate (CABS) glasses have been synthesized via quick melt quench technique. CABS: xDy3+ glasses (x = 0.1, 0.5, 1, 1.5 and 2 mol%) were subjected to various morphological and photoluminescence studies. X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy were conducted to study the structural and bonding nature of the undoped glass. The excitation spectra of Dy3+ doped CABS glasses under 574 nm emission show many sharp peaks amongst which the transition from 6H15/2 → 6P7/2 (351 nm) had the highest intensity. Under 351 nm excitation, glasses exhibit sharp peaks in the blue, yellow and red regions corresponding to the transitions 4F9/2 → 6H15/2, 6H13/2, 6H11/2 and 6H9/2 respectively. The dipole-dipole nature of the interaction between the Dy3+ ions is confirmed via Dexter theory and Inokuti-Hirayama (I-H) model. CIE coordinates estimated from the emission profiles of these glasses under 351 nm excitation fall in the white region. Considering that these glasses exhibit sharp visible emission under UV excitation, have stable yellow to blue (Y/B) ratios and fast decays with intense energy transfers, we propose to utilise these glasses for white light generation and other white light LED (w-LED) and solid-state lighting (SSL) applications.

Structural, optical, and luminescence properties of Dy3+ -activated potassium calcium silicate phosphor for white light-emitting diodes.

A dysprosium (Dy3+ )-activated potassium calcium silicate (K4 CaSi3 O9 ) phosphor was prepared using a solid-state synthesis route. The phosphor had a cubic structure with the space group Pa 3 ¯ as confirmed using X-ray diffraction (XRD) measurements. Details of surface morphology and elemental composition of the as-synthesized undoped KCS phosphor was obtained using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) spectroscopy. The chemical structure as well as the vibrational modes present in the as-prepared KCS phosphor was analyzed using Fourier transform infrared (FT-IR) spectroscopy. Diffuse reflectance spectra (DRS) were used to determine the optical bandgap of the phosphors and were found to be in the optical range 3.52-3.71 eV. Photoluminescence (PL) spectra showed intense yellow emission corresponding to the 4 F9/2 →6 H13/2 transition under 350 nm excitation. Commission International de l'Eclairage colour chromaticity coordinates were evaluated using the PL spectral data lie within the white region. Dexter theory and the Inokuti-Hirayama (I-H) model were applied to study the nature of the energy transfer mechanism in the as-prepared phosphors. The relatively high activation energy of the phosphors was evaluated using temperature-dependent PL (TDPL) data and confirmed the high thermal stability of the titled phosphor. The abovementioned results indicated that the as-prepared KCS:Dy3+ phosphor was a promising candidate for n-UV-based white light-emitting diodes.

Triamterene Functions as an Effective Nonsense Suppression Agent for MPS I-H (Hurler Syndrome).

Mucopolysaccharidosis I-Hurler (MPS I-H) is caused by the loss of α-L-iduronidase, a lysosomal enzyme that degrades glycosaminoglycans. Current therapies cannot treat many MPS I-H manifestations. In this study, triamterene, an FDA-approved, antihypertensive diuretic, was found to suppress translation termination at a nonsense mutation associated with MPS I-H. Triamterene rescued enough α-L-iduronidase function to normalize glycosaminoglycan storage in cell and animal models. This new function of triamterene operates through premature termination codon (PTC) dependent mechanisms that are unaffected by epithelial sodium channel activity, the target of triamterene's diuretic function. Triamterene represents a potential non-invasive treatment for MPS I-H patients carrying a PTC.

SARS-CoV-2 B.1.619 and B.1.620 Lineages, South Korea, 2021.

We report the rapid emergence of severe acute respiratory syndrome coronavirus 2 lineages B.1.619 and B.1.620 in South Korea. The surge in frequency in a relatively short time emphasizes the need for ongoing monitoring for new lineages to track potential increases in transmissibility and disease severity and reductions in vaccine efficacy.

Single-Pore versus Dual-Pore Bipyridine-Based Covalent-Organic Frameworks: An Insight into the Heterogeneous Catalytic Activity for Selective CH Functionalization.

Exponential growth in the field of covalent-organic frameworks (COFs) is emanating from the direct correlation between designing principles and desired properties. The comparison of catalytic activity between single-pore and dual-pore COFs is of importance to establish structure-function relationship. Herein, the synthesis of imine-linked dual-pore [(BPyDC)]x % -ETTA COFs (x = 0%, 25%, 50%, 75%, 100%) with controllable bipyridine content is fulfilled by three-component condensation of 4,4',4″,4'″-(ethene-1,1,2,2-tetrayl)tetraaniline (ETTA), 4,4'-biphenyldialdehyde, and 2,2'-bipyridyl-5,5'-dialdehyde in different stoichiometric ratio. The strong coordination of bipyridine moieties of [(BPyDC)]x % -ETTA COFs with palladium imparts efficient catalytic active sites for selective functionalization of sp2 CH bond to CX (X = Br, Cl) or CO bonds in good yield. To broaden the scope of regioselective CH functionalization, a wide range of electronically and sterically substituted substrates under optimized catalytic condition are investigated. A comparison of the catalytic activity of palladium decorated dual-pore frameworks with single-pore imine-linked Pd(II) @ Py-2,2'-BPyDC framework  is undertaken. The finding of this work provides a sporadic example of chelation-assisted CH functionalization and disclosed an in-depth comparison of the relationship between superior catalytic activity and core properties of rationally designed imine linked frameworks.

Ih, GIRK, and KCNQ/Kv7 channels differently modulate sharp wave - ripples in the dorsal and ventral hippocampus.

Sharp waves and ripples (SPW-Rs) are endogenous transient patterns of hippocampus local network activity implicated in several functions including memory consolidation, and they are diversified between the dorsal and the ventral hippocampus. Ion channels in the neuronal membrane play important roles in cell and local network function. In this study, using transverse slices and field potential recordings from the CA1 field of rat hippocampus we show that GIRK and KCNQ2/3 potassium channels play a higher role in modulating SPW-Rs in the dorsal hippocampus, while Ih and other KCNQ (presumably KCNQ5) channels, contribute to shaping SPW-R activity more in the ventral than in dorsal hippocampus. Specifically, blockade of Ih channels by ZD 7288 reduced the rate of occurrence of SPW-Rs and increased the generation of SPW-Rs in the form of clusters in both hippocampal segments, while enhanced the amplitude of SPW-Rs only in the ventral hippocampus. Most effects of ZD 7288 appeared to be independent of NMDA receptors' activity. However, the effects of blockade of NMDA receptors depended on the functional state of Ih channels in both hippocampal segments. Blockade of GIRK channels by Tertiapin-Q increased the rate of occurrence of SPW-Rs only in the dorsal hippocampus and the probability of clusters in both segments of the hippocampus. Blockade of KCNQ2/3 channels by XE 991 increased the rate of occurrence of SPW-Rs and the probability of clusters in the dorsal hippocampus, and only reduced the clustered generation of SPW-Rs in the ventral hippocampus. The blocker of KCNQ1/2 channels, that also enhances KCNQ5 channels, UCL 2077, increased the probability of clusters and the power of the ripple oscillation in the ventral hippocampus only. These results suggest that GIRK, KCNQ and Ih channels represent a key mechanism for modulation of SPW-R activity which act differently in the dorsal and ventral hippocampus, fundamentally supporting functional diversification along the dorsal-ventral axis of the hippocampus.

Skin Ultrastructure and the Changes of HIF-2α, H-FABP Expression in the Myocardium of Electric Shock Death Rats.

ABSTRACT: Objective To observe the skin ultrastructure change of electric shock death rats and to test the expression changes of hypoxia-inducible factor-2α （HIF-2α） and heart type-fatty acid-binding protein （H-FABP） of myocardial cells, in order to provide basis for forensic identification of electric shock death. Methods The electric shock model of rats was established. The 72 rats were randomly divided into control group, electric shock death group and postmortem electric shock group. Each group was divided into three subgroups, immediate （0 min）, 30 min and 60 min after death. The skin changes of rats were observed by HE staining, the changes of skin ultrastructure were observed by scanning electron microscopy, and the expression of HIF-2α and H-FABP in rats myocardium was tested by immunohistochemical staining. Results The skin in the electric shock death group and postmortem electric shock group had no significant difference through the naked eye or by HE staining. Under the scanning electron microscope, a large number of cellular debris, cells with unclear boundaries, withered cracks, circular or elliptical holes scattered on the cell surface and irregular edges were observed. A large number of spherical foreign body particles were observed. Compared with the control group, the expression of HIF-2α in all electric shock death subgroups increased, reaching the peak immediately after death. In the postmortem electric shock group, HIF-2α expression only increased immediately after death, but was lower than that of electric shock death group （P<0.05）. Compared with the control group, the expression of H-FABP in all subgroups of electric shock death group and postmortem electric shock group significantly decreased. The expression of H-FABP in all subgroups of electric shock death group was lower than that of the postmortem electric shock group （P<0.05）. Conclusion Electric shock can increase HIF-2α expression and decrease H-FABP expression in the myocardium, which may be of forensic significance for the determination of electric shock death and identification of antemortem and postmortem electric shock.

40 Years of My Venture with CYTOMETRY.

Briefly depicted are the publications in CYTOMETRY that received the highest frequency of citations. Among them are seminal papers describing application of metachromatic fluorochrome acridine orange to differentially stain DNA versus RNA or to analyze susceptibility of DNA in situ to denaturation; both features being markers of different sections of the cell cycle including identification of noncycling quiescent cells. The papers reviewing detection of cyclins D1, E, A or B1, each in relation to cell cycle phase, were also among the highly cited ones. The highest citation rates received publications describing development of the TUNEL methodology to detect apoptotic DNA fragmentation, and more recently expression of ϒH2AX to reveal DNA damage. © 2020 International Society for Advancement of Cytometry.

Cannabinoids in multiple sclerosis: A neurophysiological analysis.

OBJECTIVES: To investigate the action of cannabinoids on spasticity and pain in secondary progressive multiple sclerosis, by means of neurophysiological indexes. MATERIAL AND METHODS: We assessed 15 patients with progressive MS (11 females) using clinical scales for spasticity and pain, as well as neurophysiological variables (H/M ratio, cutaneous silent period or CSP). Testing occurred before (T0) and during (T1) a standard treatment with an oral spray containing delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). Neurophysiological measures at T0 were compared with those of 14 healthy controls of similar age and sex (HC). We then compared the patient results at the two time points (T1 vs T0). RESULTS: At T0, neurophysiological variables did not differ significantly between patients and controls. At T1, spasticity and pain scores improved, as detected by the Modified Ashworth Scale or MAS (P = .001), 9-Hole Peg Test or 9HPT (P = .018), numeric rating scale for spasticity or NRS (P = .001), and visual analogue scale for pain or VAS (P = .005). At the same time, the CSP was significantly prolonged (P = .001). CONCLUSIONS: The THC-CBD spray improved spasticity and pain in secondary progressive MS patients. The spray prolonged CSP duration, which appears a promising tool for assessing and monitoring the analgesic effects of THC-CBD in MS.

Integrative/Hybrid Methods Structural Biology: Role of Macromolecular Crystallography.

Macromolecular crystallography has been central to the emergence and development of structural biology as a scientific discipline. Approximately 90% of the more than 138,000 three-dimensional structures currently available in the Protein Data Bank (PDB) archive, the single, global open access data resource for macromolecular structure data, were determined using X-ray crystallography. MX, the enormous variety of PDB structures of proteins, DNA, and RNA, and computational models derived therefrom will be central to the growth of integrative or hybrid (I/H) methods structural studies of macromolecular assemblies and other complex biological systems.

Reduction of thalamic and cortical Ih by deletion of TRIP8b produces a mouse model of human absence epilepsy.

Absence seizures occur in several types of human epilepsy and result from widespread, synchronous feedback between the cortex and thalamus that produces brief episodes of loss of consciousness. Genetic rodent models have been invaluable for investigating the pathophysiological basis of these seizures. Here, we identify tetratricopeptide-containing Rab8b-interacting protein (TRIP8b) knockout mice as a new model of absence epilepsy, featuring spontaneous spike-wave discharges on electroencephalography (EEG) that are the electrographic hallmark of absence seizures. TRIP8b is an auxiliary subunit of the hyperpolarization-activated cyclic-nucleotide-gated (HCN) channels, which have previously been implicated in the pathogenesis of absence seizures. In contrast to mice lacking the pore-forming HCN channel subunit HCN2, TRIP8b knockout mice exhibited normal cardiac and motor function and a less severe seizure phenotype. Evaluating the circuit that underlies absence seizures, we found that TRIP8b knockout mice had significantly reduced HCN channel expression and function in thalamic-projecting cortical layer 5b neurons and thalamic relay neurons, but preserved function in inhibitory neurons of the reticular thalamic nucleus. Our results expand the known roles of TRIP8b and provide new insight into the region-specific functions of TRIP8b and HCN channels in constraining cortico-thalamo-cortical excitability.

Pd(II) -Catalyzed Intermolecular Amination of Unactivated C(sp(3) )-H Bonds.

Pd(II) -catalyzed intermolecular amination of unactivated C(sp(3) )-H bonds has been successfully developed for the first time. This method provides a new way to achieve the challenging intermolecular amination of unactivated C(sp(3) )-H bonds, producing a variety of unnatural ß(2) -amino carboxylic acid analogues. This C(sp(3) )-H amination protocol is demonstrated with a broad substrate scope, good functional-group tolerance, and chemoselectivity. It is operated without use of phosphine ligand or external oxidant.

Development of a Rhodium(II)-Catalyzed Chemoselective C(sp(3) )-H Oxygenation.

We report the first example of Rh(II) -catalyzed chemoselective double C(sp(3) )-H oxygenation, which can directly transform various toluene derivatives into highly valuable aromatic aldehydes with great chemoselectivity and practicality. The critical combination of catalyst Rh(OAc)2 , oxidant Selectfluor, and solvents of TFA/TFAA promises the successful delivery of the oxidation with satisfactory yields. A possible mechanism involving a unique carbene-Rh complex is proposed, and has been supported by both experiments and theoretical calculations.

Cp*Rh(III) -Catalyzed Arylation of C(sp(3) )-H Bonds.

The first Cp*Rh(III) -catalyzed arylation of unactivated C(sp(3) )-H bonds is presented. The unactivated primary C(sp(3) )-H bond of 2-alkylpyridines can be activated by Rh(III) and further reacts with triarylboroxines to efficiently build new C(sp(3) )-aryl bonds. The methodology also provides a facile and efficient synthesis of unsymmetrical triarylmethanes by Rh(III) -catalyzed C(sp(3) )-H arylation of diarylmethanes.

Spike-and-wave discharge mediated reduction in hippocampal HCN1 channel function associates with learning deficits in a genetic mouse model of epilepsy.

The GABAAγ2(R43Q) mouse is an established model of absence epilepsy displaying spontaneous spike-and-wave discharges (SWD) and associated behavioral arrest. Absence epilepsy typically results from cortico-thalamic networks. Nevertheless, there is increasing evidence for changes in hippocampal metabolism and electrical behavior, consistent with a link between absence seizures and hippocampus-related co-morbidities. Hyperpolarization-activated-cyclic-nucleotide-gated (HCN) channels are known to be transcriptionally regulated in a number of seizure models. Here we investigate the expression and function of these channels in the hippocampus of the genetic epilepsy model. A reduction in HCN1, but not HCN2 transcript, was observed in GABAAγ2(R43Q) mice relative to their littermate controls. In contrast, no change in HCN1 transcript was noted at an age prior to seizure expression or in a SWD-free model in which the R43Q mutation has been crossed into a seizure-resistant genetic background. Whole-cell recordings from CA1 pyramidal neurons confirm a reduction in Ih in the GABAAγ2(R43Q) mouse. Further, a left-shift in half-activation of the Ih conductance-voltage relationship is consistent with a reduction in HCN1 with no change in HCN2 channel expression. Behavioral analysis using the Morris water maze indicates that GABAAγ2(R43Q) mice are unable to learn as effectively as their wildtype littermates suggesting a deficit in hippocampal-based learning. SWD-free mice harboring the R43Q mutation had no learning deficit. We conclude that SWDs reduce hippocampal HCN1 expression and function, and that the reduction associates with a spatial learning deficit.

Subthreshold delta-frequency resonance in thalamic reticular neurons.

The thalamic reticular nucleus (nRt) is an assembly of GABAergic projection neurons that participate in the generation of brain rhythms during synchronous sleep and absence epilepsy. NRt cells receive inhibitory and excitatory synaptic inputs, and are endowed with an intricate set of intrinsic conductances. However, little is known about how intrinsic and synaptic properties interact to generate rhythmic discharges in these neurons. In order to better understand this interaction, I studied the subthreshold responses of nRt cells to time-varying inputs. Patch-clamp recordings were performed in acute slices of rat thalamus (postnatal days 12-21). Sinusoidal current waveforms of linearly changing frequencies were injected into the soma, and the resulting voltage oscillations were recorded. At the resting membrane potential, the impedance profile showed a characteristic resonance at 1.7 Hz. The relative strength of the resonance was 1.2, and increased with membrane hyperpolarization. Small suprathreshold current injections led to preferred spike generation at the resonance frequency. Bath application of ZD7288 or Cs(+) , inhibitors of the hyperpolarization-activated cation current (Ih ), transformed the resonance into low-pass behaviour, whereas the T-channel blockers mibefradil and Ni(2+) decreased the strength of the resonance. It is concluded that nRt cells have an Ih -mediated intrinsic frequency preference in the subthreshold voltage range that favours action potential generation in the delta-frequency band.

Modeling for High-Frequency Spurious Responses in Incredible High-Performance Surface Acoustic Wave Devices.

To ensure that surface acoustic wave (SAW) filters fulfill the requirements of Carrier Aggregation (CA) applications, the development of modeling tools that can forecast and simulate high-frequency spurious responses has been necessary. This paper presents an advanced methodology for extending the coupling-of-modes (COM) model to obtain precise modeling of the high-frequency spurious responses of incredible high-performance surface acoustic wave (I.H.P. SAW) devices. The extended COM (ECOM) model is derived by modifying the conventional COM model and extending it accordingly. The parameters used in this model are determined through numerical fitting. For validation, firstly, the ECOM model is applied to a one-port synchronous I.H.P. SAW resonator, and the simulation and measurement results match. Then, the structural parameters of the ECOM model are varied, and the accuracy of the model after the structural parameters are varied is verified. It is demonstrated that this model can be applied to the design work of SAW filters. Finally, the ECOM model is applied to the design of the I.H.P. SAW filter based on a 42°YX-LiTaO3 (LT)/SiO2/AlN/Si structure. By using this method, the I.H.P. SAW filter's high-frequency spurious response can be predicted more accurately.