Cyclin K-containing kinase complexes maintain self-renewal in murine embryonic stem cells

Protein phosphorylation plays an important role in the regulation of self-renewal and differentiation of embryonic stem cells. However, the responsible intracellular kinases are not well characterized. Here, we discovered that cyclin K protein was highly expressed in pluripotent embryonic stem cells but low in their differentiated derivatives or tissue-specific stem cells. Upon cell differentiation, the level of cyclin K protein was decreased. Furthermore, knockdown of cyclin K led to cell differentiation, which could be rescued by an expression construct resistant to RNA interference. Surprisingly, cyclin K did not interact with CDK9 protein in cells as thought previously. Instead, it associated with CrkRS (also known as CDK12) and CDC2L5 (also known as CDK13). Similar to cyclin K, both CDK12 and CDK13 proteins were highly expressed in murine embryonic stem cells and were decreased upon cell differentiation. Importantly, knockdown of either kinase resulted in differentiation. Thus, our studies have uncovered two novel protein kinase complexes that maintain self-renewal in embryonic stem cells.     

Pre-existing diseases of patients increase susceptibility to hypoxemia during gastrointestinal endoscopy

Hypoxemia is the most common adverse event that happened during gastrointestinal endoscopy. To estimate risk of hypoxemia prior to endoscopy, American Society of Anesthesiology (ASA) classification scores were used as a major predictive factor. But the accuracy of ASA scores for predicting hypoxemia incidence was doubted here, considering that the classification system ignores much information about general health status and fitness of patient that may contribute to hypoxemia. In this retrospective review of clinical data collected prospectively, the data on 4904 procedures were analyzed. The Pearson's chi-square test or the Fisher exact test was employed to analyze variance of categorical factors. Continuous variables were statistically evaluated using t-tests or Analysis of variance (ANOVA). As a result, only 245 (5.0%) of the enrolled 4904 patients were found to present hypoxemia during endoscopy. Multivariable logistic regressions revealed that independent risk factors for hypoxemia include high BMI (BMI 30 versus 20, Odd ratio: 1.52, 95% CI: 1.13-2.05; P?=?0.0098), hypertension (Odd ratio: 2.28, 95% CI: 1.44-3.60; P?=?0.0004), diabetes (Odd ratio: 2.37, 95% CI: 1.30-4.34; P?=?0.005), gastrointestinal diseases (Odd ratio: 1.77, 95% CI: 1.21-2.60; P?=?0.0033), heart diseases (Odd ratio: 1.97, 95% CI: 1.06-3.68; P?=?0.0325) and the procedures that combined esophagogastroduodenoscopy (EGD) and colonoscopy (Odd ratio: 4.84, 95% CI: 1.61-15.51; P?=?0.0292; EGD as reference). It is noteworthy that ASA classification scores were not included as an independent predictive factor, and susceptibility of youth to hypoxemia during endoscopy was as high as old subjects. In conclusion, some certain pre-existing diseases of patients were newly identified as independent risk factors for hypoxemia during GI endoscopy. High ASA scores are a confounding predictive factor of pre-existing diseases. We thus recommend that youth (≤18 yrs), obese patients and those patients with hypertension, diabetes, heart diseases, or GI diseases should be monitored closely during sedation endoscopy.     

Effects of Mycobacterium tuberculosis ESAT-6/CFP-10 fusion protein on the autophagy function of mouse macrophages

Autophagy plays specific roles in host innate and adaptive immune responses to numerous intracellular pathogens, including Mycobacterium tuberculosis. The ESAT-6 and CFP-10 proteins are secreted by M. tuberculosis and play important roles in pathogenesis. We hypothesized that these two proteins may affect the autophagy function of host macrophages during infection with M. tuberculosis, thereby shaping the immune reaction toward the pathogen. Interestingly, we found that rapamycin-induced autophagy of macrophages infected with M. tuberculosis H37Rv enhanced localization of mycobacteria with autophagosomes and lysosomes. Ectopic expression of the ESAT-6/CFP-10 fusion in macrophages dramatically inhibited autophagosome formation, and M. tuberculosis survival inside infected macrophages was significantly affected as well. Further, M. tuberculosis viability was increased by the fusion protein. Expression levels of autophagy-related genes (ATG), especially atg8, also decreased (p<0.05). These results suggested that ESAT-6 and CFP-10 proteins play significant roles in autophagy formation in M. tuberculosis infection and that autophagosome formation is regulated through the expression of ATG.     

Elimination of KATP channels in mouse islets results in elevated [U-13C]glucose metabolism, glutaminolysis, and pyruvate cycling but a decreased gamma-aminobutyric acid shunt

Pancreatic beta cells are hyper-responsive to amino acids but have decreased glucose sensitivity after deletion of the sulfonylurea receptor 1 (SUR1) both in man and mouse. It was hypothesized that these defects are the consequence of impaired integration of amino acid, glucose, and energy metabolism in beta cells. We used gas chromatography-mass spectrometry methodology to study intermediary metabolism of SUR1 knock-out (SUR1(-/-)) and control mouse islets with d-[U-(13)C]glucose as substrate and related the results to insulin secretion. The levels and isotope labeling of alanine, aspartate, glutamate, glutamine, and gamma-aminobutyric acid (GABA) served as indicators of intermediary metabolism. We found that the GABA shunt of SUR1(-/-) islets is blocked by about 75% and showed that this defect is due to decreased glutamate decarboxylase synthesis, probably caused by elevated free intracellular calcium. Glutaminolysis stimulated by the leucine analogue d,l-beta-2-amino-2-norbornane-carboxylic acid was, however, enhanced in SUR1(-/-) and glyburide-treated SUR1(+/+) islets. Glucose oxidation and pyruvate cycling was increased in SUR1(-/-) islets at low glucose but was the same as in controls at high glucose. Malic enzyme isoforms 1, 2, and 3, involved in pyruvate cycling, were all expressed in islets. High glucose lowered aspartate and stimulated glutamine synthesis similarly in controls and SUR1(-/-) islets. The data suggest that the interruption of the GABA shunt and the lack of glucose regulation of pyruvate cycling may cause the glucose insensitivity of the SUR1(-/-) islets but that enhanced basal pyruvate cycling, lowered GABA shunt flux, and enhanced glutaminolytic capacity may sensitize the beta cells to amino acid stimulation.     

Construction of a rAAV-SaCas9 system expressing eGFP and its application to improve muscle mass

Biotechnology Letters - An ideal rAAV gene editing system not only effectively edits genes at specific site, but also prevents the spread of the virus from occurring off-target or carcinogenic...     

Assessment of right atrium dysfunction in patients with obstructive sleep apnea syndrome using velocity vector imaging

Background and Objectives

This study aimed to assess the changes of RA function in patients with obstructive sleep apnea syndrome (OSAS) using velocity vector imaging (VVI) and to evaluate the application of VVI technology.

Methods

According to the apnea–hypopnea index (AHI), 71 patients with OSAS were divided into three groups: mild, moderate, and severe. A total of 30 cases of healthy subjects were enrolled as the control group. Digital images of apex four-chamber views were acquired to measure the right atrium (RA) linear dimensions and volume parameters including RA longitudinal diameter (RAL), transverse diameter (RAT), RA maximum volume (Vmax), RA minimum volume (Vmin), right atrial volume before contraction (Vpre). Right atrial volume parameters were corrected by body surface area (VImax, VImin, VIpre). The total right atrial emptying fraction (RATEF), right atrial passive emptying fraction (RAPEF), right atrial active contraction emptying fraction (RAAEF) were calculated. The VVI data measuring right atrial global strain (RA-GLS), right atrial strain rate in ventricular systolic phase (RA-SRs), right atrial strain rate in ventricular early diastolic phase (RA-SRe), right atrial strain rate in ventricular late diastolic phase (RA-SRa).

Results

1. 1.
   RA linear dimensions and volume parameters in severe OSAS were higher than those of control group. RAPEF in severe group was lower than control group and mild OSAS group (t?= 2.681, P?=?0.021; t?= 2.985, P?=?0.011; respectively). RAAEF in OSAS moderate group was higher than that of control group (t?= 3.006, P?=?0.02), and without statistical difference (P?>?0.05) in the severe OSAS group and the control group.
    
2. 2.
   RA-GLS in moderate OSAS group was significantly lower than that of control group (t?= 2.333, P?=?0.040) and reduced more obvious in the severe OSAS group (vs control, t?= 3.25, P?=?0.008, vs mild; t?= 3.011, P?=?0.012; respectively). RA-SRe in moderate and severe OSAS groups were lower than control group (t?= 2.466, P?=?0.031; t?= 3.547, P?=?0.005; respectively). RA-SRs of OSAS in severe group was lower than that of control and mild groups (t?= 3.665, P?=?0.004; t?= 3.204, P?=?0.008; respectively). RA-SRa in severe OSAS group was lower than that of control group (t?= 2.425, P?=?0.034).
    
3. 3.
   Multivariate regression analysis showed that RA-GLS and RA-SRe were independently correlated with AHI (t?=???2.738, P?=?0.010; t?=???2.191, P?=?0.036; respectively).
    

Conclusion

RA function was impaired in patients with OSAS. On hemodynamics, the change of RA function performed increased of reserve function, reduced pipeline function and increased of contraction function. However, the strain and strain rate reduced in different degree. RA-GLS and RA-SRe decreased the earliest, which suggested that strain and strain rate were the parameters which can reflect myocardial function damage earliest. VVI can more earlier and accurately detect myocardial dysfunction of right atrium in patients with OSAS, which is expected to be a worthy technique for early clinical therapy in patients with OSAS.

     

Vezatin regulates seizures by controlling AMPAR-mediated synaptic activity

Although many studies have explored the mechanism of epilepsy, it remains unclear and deserves further investigation. Vezatin has been reported to be a synaptic regulatory protein involved in regulating neuronal synaptic transmission (NST). However, the role of vezatin in epilepsy remains unknown. Therefore, the aims of this study are to investigate the underlying roles of vezatin in epilepsy. In this study, vezatin expression was increased in hippocampal tissues from pilocarpine (PILO)-induced epileptic mice and a Mg²⁺-free medium-induced in vitro seizure-like model. Vezatin knockdown suppressed seizure activity in PILO-induced epileptic mice. Mechanistically, vezatin knockdown suppressed AMPAR-mediated synaptic events in epileptic mice and downregulated the surface expression of the AMPAR GluA1 subunit (GluA1). Interestingly, vezatin knockdown decreased the phosphorylation of GluA1 at serine 845 and reduced protein kinase A (PKA) phosphorylation; when PKA phosphorylation was suppressed by H-89 (a selective inhibitor of PKA phosphorylation) in vitro, the effects of vezatin knockdown on reducing the phosphorylation of GluA1 at serine 845 and the surface expression of GluA1 were blocked. Finally, we investigated the pattern of vezatin in brain tissues from patients with temporal lobe epilepsy (TLE), and we found that vezatin expression was also increased in patients with TLE. In summary, the vezatin expression pattern is abnormal in individuals with epilepsy, and vezatin regulates seizure activity by affecting AMPAR-mediated NST and the surface expression of GluA1, which is involved in PKA-mediated phosphorylation of GluA1 at serine 845, indicating that vezatin-mediated regulation of epileptic seizures represents a novel target for epilepsy.Subject terms: Cellular neuroscience, Molecular neuroscience     

酸性硫酸盐土水改旱后土壤化学性状的变异初报

探讨了酸性硫酸盐水稻土改为旱作后土壤化学性状的变异以及比较不同利用方式之间的经济效益．结果表明,酸性硫酸盐水稻土改种甜玉米和蔬菜后,土壤化学性状发生显著变化．耕层土壤酸度、水溶性硫酸根含量、土壤活性铝和活性铁含量均显著降低．经济效益得到显著提高．建议对水改旱后的环境效应进行深入研究以及进行定位观测,以便合理利用这一特殊的土壤资源     

Interface Welding via Thermal Pulse Sintering to Enable 4.6 V Solid-State Batteries

NASICON-type Li_1.3Al_0.3Ti_1.7(PO4)₃ (LATP) is one of the most promising solid-state electrolytes (SSEs) to achieve high-energy-density solid-state batteries (SSBs) due to its high ionic conductivity, high-voltage stability, and low cost. However, its practical application is constrained by inadequate interfacial compatibility with cathode materials and significant incompatibility with lithium metal. In this work, a cost-effective interface welding approach is reported, utilizing an innovative thermal pulse sintering (TPS) to fabricate LATP-based solid-state batteries. Initially, the rapid thermal pulses enhance the ionic conductivity of LATP SSE by inducing selective growth of LATP nanowires, effectively occupying interparticle voids. Additionally, this process results in the formation of a dense layer (GCM) comprising graphene oxide, carbon nanotubes, and MXene with a controlled Li⁺ transport pathway, facilitating lithium stripping and plating processes. Moreover, these thermal pulses facilitate the interfacial fusion between LATP and cathode materials, while avoiding undesired phase diffusion. As a result, SSBs with a LiCoO₂ cathode deliver favorable cycle stability at 4.6 V, marking significant progress. This facile interface welding strategy represents a substantial step toward high-energy-density SSB development.