EHMT2 suppresses the variation of transcriptional switches in the mouse embryo.

EHMT2 is the main euchromatic H3K9 methyltransferase. Embryos with zygotic, or maternal mutation in the Ehmt2 gene exhibit variable developmental delay. To understand how EHMT2 prevents variable developmental delay we performed RNA sequencing of mutant and somite stage-matched normal embryos at 8.5-9.5 days of gestation. Using four-way comparisons between delayed and normal embryos we clarified what it takes to be normal and what it takes to develop. We identified differentially expressed genes, for example Hox genes that simply reflected the difference in developmental progression of wild type and the delayed mutant uterus-mate embryos. By comparing wild type and zygotic mutant embryos along the same developmental window we detected a role of EHMT2 in suppressing variation in the transcriptional switches. We identified transcription changes where precise switching during development occurred only in the normal but not in the mutant embryo. At the 6-somite stage, gastrulation-specific genes were not precisely switched off in the Ehmt2-/- zygotic mutant embryos, while genes involved in organ growth, connective tissue development, striated muscle development, muscle differentiation, and cartilage development were not precisely switched on. The Ehmt2mat-/+ maternal mutant embryos displayed high transcriptional variation consistent with their variable survival. Variable derepression of transcripts occurred dominantly in the maternally inherited allele. Transcription was normal in the parental haploinsufficient wild type embryos despite their delay, consistent with their good prospects. Global profiling of transposable elements revealed EHMT2 targeted DNA methylation and suppression at LTR repeats, mostly ERVKs. In Ehmt2-/- embryos, transcription over very long distances initiated from such misregulated 'driver' ERVK repeats, encompassing a multitude of misexpressed 'passenger' repeats. In summary, EHMT2 reduced transcriptional variation of developmental switch genes and developmentally switching repeat elements at the six-somite stage embryos. These findings establish EHMT2 as a suppressor of transcriptional and developmental variation at the transition between gastrulation and organ specification.

Room-Temperature Magnetic Phase Transition in an Electrically Tuned van der Waals Ferromagnet.

Finding tunable van der Waals (vdW) ferromagnets that operate at above room temperature is an important research focus in physics and materials science. Most vdW magnets are only intrinsically magnetic far below room temperature and magnetism with square-shaped hysteresis at room temperature has yet to be observed. Here, we report magnetism in a quasi-2D magnet Cr_{1.2}Te_{2} observed at room temperature (290 K). This magnetism was tuned via a protonic gate with an electron doping concentration up to 3.8×10^{21} cm^{-3}. We observed nonmonotonic evolutions in both coercivity and anomalous Hall resistivity. Under increased electron doping, the coercivities and anomalous Hall effects (AHEs) vanished, indicating a doping-induced magnetic phase transition. This occurred up to room temperature. DFT calculations showed the formation of an antiferromagnetic (AFM) phase caused by the intercalation of protons which induced significant electron doping in the Cr_{1.2}Te_{2}. The tunability of the magnetic properties and phase in room temperature magnetic vdW Cr_{1.2}Te_{2} is a significant step towards practical spintronic devices.

PARP1 and CHK1 coordinate PLK1 enzymatic activity during the DNA damage response to promote homologous recombination-mediated repair.

Polo-like kinase 1 (PLK1) is a master kinase that regulates cell cycle progression. How its enzymatic activity is regulated in response to DNA damage is not fully understood. We show that PLK1 is enriched at double strand breaks (DSBs) within seconds of UV laser irradiation in a PARP-1-dependent manner and then disperses within 10 min in a PARG-dependent manner. Poly(ADP-)ribose (PAR) chains directly bind to PLK1 in vitro and inhibit its enzymatic activity. CHK1-mediated PLK1 phosphorylation at S137 prevents its binding to PAR and recruitment to DSBs but ensures PLK1 phosphorylation at T210 and its enzymatic activity toward RAD51 at S14. This subsequent phosphorylation event at S14 primes RAD51 for CHK1-mediated phosphorylation at T309, which is essential for full RAD51 activation. This CHK1-PLK1-RAD51 axis ultimately promotes homologous recombination (HR)-mediated repair and ensures chromosome stability and cellular radiosensitivity. These findings provide biological insight for combined cancer therapy using inhibitors of PARG and CHK1.

[Epidemiology and hospitalization costs analysis of female inpatients with acute exacerbation of chronic obstructive pulmonary disease in Beijing from 2013 to 2020].

OBJECTIVE: To study epidemiological characteristics and hospitalization costs of female inpatients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) in Beijing. METHODS: A retrospective study was conducted to analyze electronic hospitalization summary reports of female inpatients with AECOPD in Beijing from 2013 to 2020. Clinical characteristics (age distribution and comorbidities), epidemiological characteristics (temporal and spatial distribution characteristics), hospi-talization times and costs of patients were described. RESULTS: A total of 57 911 subjects in 166 hospitals were included in this study, with a mean age of (78.84±8.59) years and the highest number of patients aged 80-89 years (49.06%), followed by patients aged 70-79 years (31.08%), and the lowest number of patients under 50 years (0.41%). The proportions of patients with coronary heart disease, hypertension and heart failure were 30.60%, 30.52% and 26.54% respectively. The median number of daily hospitalizations during the study period was 18 (IQR: 16). The number of daily hospitalizations for AECOPD showed an overall growth trend over the eight years from 2013 to 2020, starting to increase significantly in 2015 and continuing to increase until 2019, then followed by a decline in 2020. The proportion of inpatient admissions was higher in winter and spring (54.09%) than that in summer and autumn (45.91%). The top three districts in terms of the proportion of total inpatient admissions were Xicheng district (14.18%), Chaoyang district (14.12%) and Fengtai district (13.47%). The density of inpatients was relatively high in the western regions, central urban areas and northeastern regions of the city, while the density of inpatients was relatively low in the near suburbs. The median number of hospital days for female patients with AECOPD was 12 days, and the median hospital costs was CNY 20 648.37. Patients from urban areas had longer hospitalization times and higher hospitalization costs than those from suburban areas (P < 0.001). Western medicine expenses accounted for the largest proportion of total hospital expenses (33.32%). During the study period, hospitalization costs exhibited an overall pattern of initial growth, followed by subsequent decline, eventually stabilizing. The differences in hospitalization costs among the patients with different comorbidities were significant. CONCLUSION: Female hospitalized patients with AECOPD in Beijing were older than 70 years, often complicated by cardiovascular disease. AECOPD occurred mainly in winter and spring, with regional differences. The hospitalization costs were closely associated with the patients' age, comorbidities, and the geographicical region.

A severe case of human coronavirus 229E pneumonia in an elderly man with diabetes mellitus: a case report.

BACKGROUND: With pandemic of coronavirus disease 2019 (COVID-19), human coronaviruses (HCoVs) have recently attached worldwide attention as essential pathogens in respiratory infection. HCoV-229E has been described as a rare cause of lower respiratory infection in immunocompetent adults. CASE PRESENTATION: We reported a 72-year-old man infected by HCoV-229E with rapid progression to acute respiratory distress syndrome, in conjunction with new onset atrial fibrillation, intensive care unit acquired weakness, and recurrent hospital acquired pneumonia. Clinical and radiological data were continuously collected. The absolute number of peripheral T cells and the level of complement components diminished initially and recovered after 2 months. The patient was successfully treated under intensive support care and discharged from the hospital after 3 months and followed. CONCLUSION: HCoV-229E might an essential causative agent of pulmonary inflammation and extensive lung damage. Supportive treatment was essential to HCoVs infection on account of a long duration of immunological recovery in critical HCoV-229E infection.

A PET imaging study of the brain changes of glucose metabolism in patients with temporal lobe epilepsy and depressive disorder.

BACKGROUND: This study aims to compare the difference of the brain changes of glucose metabolism between temporal lobe epilepsy patients (TLE) with major depressive disorder and temporal TLE without major depressive disorder. METHODS: A total of 24 TLE patients, who met the inclusion criteria of our hospital, were enrolled in this study. They were divided into a TLE with depression group (n = 11) and a TLE without depression group (n = 13), according to the results of the HAMD-24 Scale. Two groups patients were examined using 18F-FDG PET brain imaging. RESULTS: The low metabolic regions of the TLE with depression group were mainly found in the left frontal lobe, temporal lobe and fusiform gyrus, while the high metabolic regions of the TLE with depression group were mainly located in the right frontal lobe, visual joint cortex and superior posterior cingulate cortex. Both of the TLE groups had high metabolic compensation in the non-epileptic area during the interictal period. CONCLUSIONS: There is an uptake difference of 18F-FDG between TLE patients with depression and TLE patients without depression in multiple encephalic regions.

Motif based high-throughput structure prediction of superconducting monolayer titanium boride.

Two-dimensional boron structures, due to their diverse properties, have attracted great attention because of their potential applications in nanoelectronic devices. A series of TiBn (2 ≤ n ≤ 13) monolayers are efficiently constructed through our motif based method and theoretically investigated through high-throughput first-principles calculations. The configurations are generated based on the motifs of boron dimeric/triangular/quadrilateral fragments and multi-coordinate titanium-centered boron molecular wheels. Besides previously reported TiB4 and TiB9 which were discovered by the global search method, we predict that high symmetry monolayer TiB7 (Cmmm), which is octa-coordinate titanium boride, is dynamically stable. The TiB7 monolayer is a BCS superconductor with a transition temperature Tc of up to 8.3 K. The motif based approach is proved to be efficient in searching stable structures with prior knowledge so that the potentially stable transition metal monolayers can be quickly constructed by using basic cluster motifs. As an efficient way of discovering materials, the method is easily extended to predict other types of materials which have common characteristic patterns in the structure.

Atom Classification Model for Total Energy Evaluation of Two-Dimensional Multicomponent Materials.

The tunable properties of materials originate from variety of structures; however, it is still a challenge to give an accurate and fast evaluation of stabilities for screening numerous candidates. Herein, we propose an atom classification model to describe the multicomponent materials based on the structural recognition, in which the atoms are classified to estimate the total energies. Taking two-dimensional planar C1-xBx and C1-2x(BN)x as examples, we have found that the test error of total energies is about 3 meV per atom. Notably, the distributions of classified atoms demonstrate the evolution of configurations as a function of temperature, providing a clearer picture of phase transition. In addition, our method is universal, which can be flexibly extended to the bulk structures with more components.

Synthesis and cytotoxic activity of chalcone analogues containing a thieno[2,3-d]pyrimidin-2-yl group as the A-ring or B-ring.

Many natural or synthetic chalcones have potential anti-tumor activity. Here, we synthesized two series of chalcone analogues containing a thieno[2,3-d]pyrimidin-2-yl group and evaluated for their cytotoxic activity towards cultured human lung cancer A549 and colorectal HCT-116 cells. Among them, compound 8d was the most cytotoxic against HCT-116 cells, with an IC50 value of 2.65 µM. Analyses of the phenotypic changes induced by this compound found a dose-dependent accumulation of HCT-116 cells in sub-G1 phase, indicating that compound 8d might induce apoptosis. Furthermore, we found that 8d triggered mitochondrial membrane potential depolarization, promoted reactive oxygen species formation in HCT-116 cells, and increased the percentage of early and late apoptotic cells. Finally, immunoblotting indicated that 8d increased PARP-1 and caspases 3, 7 and 9 cleavage. These data suggest that compound 8d induces apoptosis via the mitochondrial death pathway.

Two-Dimensional Anti-Van't Hoff/Le Bel Array AlB6 with High Stability, Unique Motif, Triple Dirac Cones, and Superconductivity.

We report the discovery of a rule-breaking two-dimensional aluminum boride (AlB6-ptAl-array) nanosheet with a planar tetracoordinate aluminum (ptAl) array in a tetragonal lattice by comprehensive crystal structure search, first-principles calculations, and molecular dynamics simulations. It is a brand new 2D material with a unique motif, high stability, and exotic properties. These anti-van't Hoff/Le Bel ptAl-arrays are arranged in a highly ordered way and connected by two sheets of boron rhomboidal strips above and below the array. The regular alignment and strong bonding between the constituents of this material lead to very strong mechanical strength (in-plane Young's modulus Y x = 379, Y y = 437 N/m, much larger than that of graphene, Y = 340 N/m) and high thermal stability (the framework survived simulated annealing at 2080 K for 10 ps). Additionally, electronic structure calculations indicate that it is a rare new material with triple Dirac cones, Dirac-like fermions, and node-loop features. Remarkably, this material is predicted to be a 2D phonon-mediated superconductor with Tc = 4.7 K, higher than the boiling point of liquid helium (4.2 K). Surprisingly, the Tc can be greatly enhanced up to 30 K by applying tensile strain at 12%. This is much higher than the temperature of liquid hydrogen (20.3 K). These outstanding properties may pave the way for potential applications of an AlB6-ptAl-array in nanoelectronics and nanomechanics. This work opens up a new branch of two-dimensional aluminum boride materials for exploration. The present study also opens a field of two-dimensional arrays of anti-van't Hoff/Le Bel motifs for study.

Evaluation and application of donors with primary central nervous system tumors.

BACKGROUND: This study aimed to explore the safety of donors with primary central nervous system tumors for kidney and liver transplantations. METHODOLOGY: Clinical data of 29 donors with primary CNS tumors in January 2007 to December 2017, as well as the follow-up data of 16 liver transplant recipients and 46 kidney transplant recipients, were analyzed. According to the risk factors, the high-risk group was classified as Group 1, the low-risk factors were classified as Group 2, and the unknown risk group was classified as Group 3. The incidence of donor-transmitted CNS tumors was calculated and compared. RESULTS: The duration from the diagnosis of 29 donors to donation was 5.67 ± 6.36 months. None of the liver and kidney transplant recipients who were followed up had tumor metastasis. Although the mean survival time of Group 1 was lower than that of Group 2 and Group 3, the Kaplan-Meier curve showed no significant difference in survival time. CONCLUSION: No obvious difference was observed between high-risk and low-risk and unknown risk CNS tumors in terms of the survival rate of transplants and tumor metastasis rate. High-risk CNS tumor donors can be used with the informed consent of recipients after a full evaluation.

FDG-PET/CT of invasive thymoma extending into the superior vena cava and right atrium.

We present FDG PET/CT findings of a rare case of invasive thymoma with intraluminal growth into the superior vena cava (SVC) and right atrium (RA).

[Tracking Early Reperfused Myocardial Infarction using Cardiac MR].

OBJECTIVE: To determine segmental myocardial changes in cardiovascular magnetic resonance feature-tracking (CMR-FT) in the early phase of reperfused myocardial infarction in patients and rats. METHODS: Ten patients receiving percutaneous coronary interventions (2-10 d) and 10 rats with 60 min induced myocardial ischemia followed by reperfusions (48 h and 7 d) were investigated by MRI. The steady state free precession cine and late gadolinium enhancement (LGE) sequences were measured to evaluate the standard short axis of the whole heart after an injection of gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA, Magnevist, Bayer Health Care Pharmaceuticals) at a dose of 0.1 mmol/kg. The infarction sizes (all areas were expressed as a percentage of the whole myocardial tissues of left ventricle (LV), end-diastolic volume (EDV) and ejection fractions (EF) were calculated. The MRI cine images were analyzed using the myocardial feature tracking software CVI, estimating the peak value of radial strains (RS) and circumferential strains (CS) of the 16 AHA segments excluding apex cordis. The complete myocardial infarction (CMI) segments, partial myocardial infarction (PMI) segments and non-myocardial infarction (NMI) segments were identified and compared. RESULTS: Patients: The radial strain and circumferential strain of the CMI and PMI segments were smaller than the NMI segment (both P < 0.01). However, there was no significant difference between the CMI and the PMI segment (P>0.05). Rats: No significance differences were found in EF and EDV between the two time period 48 h and 7 d (both P>0.05). The radial strain and circumferential strain of the CMI and PMI segments were smaller than the NMI segment (all P < 0.01). But there was no significance difference between the CMI segment and the PMI segment (P>0.05). No significant changes in the global radial strain and the circumferential strain were found over time (both P>0.05). But the segmental radial strain and circumferential strain became larger over time (all P < 0.05). CONCLUSIONS: The systolic ability of myocardium decreases as a result of reperfusion injury in the early phase of reperfused myocardial infarction. But it can gradually recover over time with reperfusion.

Checkpoint kinase 1-induced phosphorylation of O-linked ß-N-acetylglucosamine transferase regulates the intermediate filament network during cytokinesis.

Checkpoint kinase 1 (Chk1) is a kinase instrumental for orchestrating DNA replication, DNA damage checkpoints, the spindle assembly checkpoint, and cytokinesis. Despite Chk1's pivotal role in multiple cellular processes, many of its substrates remain elusive. Here, we identified O-linked ß-N-acetylglucosamine (O-GlcNAc)-transferase (OGT) as one of Chk1's substrates. We found that Chk1 interacts with and phosphorylates OGT at Ser-20, which not only stabilizes OGT, but also is required for cytokinesis. Phospho-specific antibodies of OGT-pSer-20 exhibited specific signals at the midbody of the cell, consistent with midbody localization of OGT as reported previously. Moreover, phospho-deficient OGT (S20A) cells attenuated cellular O-GlcNAcylation levels and also reduced phosphorylation of Ser-71 in the cytoskeletal protein vimentin, a modification critical for severing vimentin filament during cytokinesis. Consequently, elongated vimentin bridges were observed in cells depleted of OGT via an siOGT-based approach. Lastly, expression of plasmids resistant to siOGT efficiently rescued the vimentin bridge phenotype, but the OGT-S20A rescue plasmids did not. Our results suggest a Chk1-OGT-vimentin pathway that regulates the intermediate filament network during cytokinesis.

Theoretical investigations on diamondoids (CnHm, n = 10-41): Nomenclature, structural stabilities, and gap distributions.

Combining the congruence check and the first-principles calculations, we have systematically investigated the structural stabilities and gap distributions of possible diamondoids (CnHm) with the carbon numbers (n) from 10 to 41. A simple method for the nomenclature is proposed, which can be used to distinguish and screen the candidates with high efficiency. Different from previous theoretical studies, the possible diamondoids can be enumerated according to our nomenclature, without any pre-determination from experiments. The structural stabilities and electronic properties have been studied by density functional based tight binding and first-principles methods, where a nearly linear correlation is found between the energy gaps obtained by these two methods. According to the formation energy of structures, we have determined the stable configurations as a function of chemical potential. The maximum and minimum energy gaps are found to be dominated by the shape of diamondoids for clusters with a given number of carbon atoms, while the gap decreases in general as the size increases due to the quantum confinement.

O-GlcNAcylation Antagonizes Phosphorylation of CDH1 (CDC20 Homologue 1).

The anaphase promoting complex/cyclosome (APC/C) orchestrates various aspects of the eukaryotic cell cycle. One of its co-activators, Cdh1, is subject to myriad post-translational modifications, such as phosphorylation and ubiquitination. Herein we identify the O-linked N-acetylglucosamine (O-GlcNAc) modification that occurs on Cdh1. Cdh1 is O-GlcNAcylated in cultured cells and mouse brain extracts. Mass spectrometry identifies an O-GlcNAcylated peptide that neighbors a known phosphorylation site. Cell synchronization and mutation studies reveal that O-GlcNAcylation of Cdh1 may antagonize its phosphorylation. Our results thus reveal a pivotal role of O-GlcNAcylation in regulating APC/C activity.

Two-Dimensional Semiconducting Boron Monolayers.

The two-dimensional boron monolayers were reported to be metallic both in previous theoretical predictions and experimental observations. Unexpectedly, we have first found a family of boron monolayers with the novel semiconducting property as confirmed by the first-principles calculations with the quasi-particle G0W0 approach. We demonstrate that the connected network of hexagonal vacancies dominates the gap opening for both the in-plane s+px,y and pz orbitals, with which various semiconducting boron monolayers are designed to realize the band gap engineering for the potential applications in electronic devices. The semiconducting boron monolayers in our predictions are expected to be synthesized on the proper substrates, due to the similar stabilities to the ones observed experimentally.

Phonon-mediated superconductivity in Mg intercalated bilayer borophenes.

Using first-principles calculations, we investigate the structural, electronic and superconducting properties of Mg intercalated bilayer borophenes BxMgBx (x = 2-5). Remarkably, B2MgB2 and B4MgB4 are predicted to exhibit good phonon-mediated superconductivity with a high transition temperature (Tc) of 23.2 K and 13.3 K, respectively, while B4MgB4 is confirmed to be more practical based on the analyses of its stability. The densities of states of in-plane orbitals at the Fermi level are found to be dominant at the superconducting transition temperature in Mg intercalated bilayer borophenes, providing an effective avenue to explore Mg-B systems with high Tcs.

Modulation of LSD1 phosphorylation by CK2/WIP1 regulates RNF168-dependent 53BP1 recruitment in response to DNA damage.

Proper DNA damage response is essential for the maintenance of genome integrity. The E3 ligase RNF168 deficiency fully prevents both the initial recruitment and retention of 53BP1 at sites of DNA damage. In response to DNA damage, RNF168-dependent recruitment of the lysine-specific demethylase LSD1 to the site of DNA damage promotes local H3K4me2 demethylation and ubiquitination of H2A/H2AX, facilitating 53BP1 recruitment to sites of DNA damage. Alternatively, RNF168-mediated K63-linked ubiquitylation of 53BP1 is required for the initial recruitment of 53BP1 to sites of DNA damage and for its function in repair. We demonstrated here that phosphorylation and dephosphorylation of LSD1 at S131 and S137 was mediated by casein kinase 2 (CK2) and wild-type p53-induced phosphatase 1 (WIP1), respectively. LSD1, RNF168 and 53BP1 interacted with each other directly. CK2-mediated phosphorylation of LSD1 exhibited no impact on its interaction with 53BP1, but promoted its interaction with RNF168 and RNF168-dependent 53BP1 ubiquitination and subsequent recruitment to the DNA damage sites. Furthermore, overexpression of phosphorylation-defective mutants failed to restore LSD1 depletion-induced cellular sensitivity to DNA damage. Taken together, our results suggest that LSD1 phosphorylation modulated by CK2/WIP1 regulates RNF168-dependent 53BP1 recruitment directly in response to DNA damage and cellular sensitivity to DNA damaging agents.

Synthesis and antitumor activity evaluation of quinazoline derivatives bearing piperazine-1-carbodithioate moiety at C4-position.

A series of quinazoline derivatives bearing piperazine-1-carbodithioate moiety at the C4-position were synthesized using piperidine and 1-bromo-3-chloropropane as starting materials via eight steps. Final compounds 8a-q and 9a-i were evaluated for their antiproliferative activity against human lung cancer A549, breast adenocarcinoma MCF-7, and colorectal cancer HCT-116 cell lines. The results showed that fourteen of twenty-six final compounds inhibited the proliferation of three cancer cell lines with IC50 values less than 10µM. When treated with a representative compound 8n, HCT-116 cells were arrested at G0/G1 phase of the cell cycle. This provided a clue to further investigation of the mechanism of action.