Aging-disturbed FUS phase transition impairs hematopoietic stem cells by altering chromatin structure.

ABSTRACT: Aged hematopoietic stem cells (HSCs) exhibit compromised reconstitution capacity. The molecular mechanisms behind this phenomenon are not fully understood. Here, we observed that the expression of FUS is increased in aged HSCs, and enforced FUS recapitulates the phenotype of aged HSCs through arginine-glycine-glycine-mediated aberrant FUS phase transition. By using Fus-gfp mice, we observed that FUShigh HSCs exhibit compromised FUS mobility and resemble aged HSCs both functionally and transcriptionally. The percentage of FUShigh HSCs is increased upon physiological aging and replication stress, and FUSlow HSCs of aged mice exhibit youthful function. Mechanistically, FUShigh HSCs exhibit a different global chromatin organization compared with FUSlow HSCs, which is observed in aged HSCs. Many topologically associating domains (TADs) are merged in aged HSCs because of the compromised binding of CCCTC-binding factor with chromatin, which is invoked by aberrant FUS condensates. It is notable that the transcriptional alteration between FUShigh and FUSlow HSCs originates from the merged TADs and is enriched in HSC aging-related genes. Collectively, this study reveals for the first time that aberrant FUS mobility promotes HSC aging by altering chromatin structure.

18ß-glycyrrhetinic acid alleviates radiation-induced skin injury by activating the Nrf2/HO-1 signaling pathway.

Radiation-induced skin injury is a common side effect of radiotherapy, but there are few therapeutic drugs available for prevention or treatment. In this study, we demonstrate that 18ß-Glycyrrhetinic acid (18ß-GA), a bioactive component derived from Glycyrrhiza glabra, substantially reduces the accumulation of reactive oxygen species (ROS) and inhibits apoptosis in HaCaT cells after ionizing radiation (IR), thereby mitigating radiation-induced skin injury. Mechanistically, 18ß-GA promotes the nuclear import of Nrf2, leading to activation of the Nrf2/HO-1 signaling pathway in response to IR. Importantly, Nrf2 silencing increases cell apoptosis and reverse the protective effect of 18ß-GA on radiation-induced skin injury. Furthermore, 18ß-GA preserves skin tissue structure after irradiation, inhibits inflammatory cell infiltration, and alleviates radiation dermatitis. In conclusion, our results suggest that 18ß-GA reduces intracellular ROS production and apoptosis by activating the Nrf2/HO-1 signaling pathway, leading to amelioration of radiation dermatitis.

The exact phenomenon and early signaling events of the endothelial cytoskeleton response to ultrasound.

Low-intensity ultrasound can be applied for medical imaging and disease treatment in clinical and experimental studies. However, the biological effects of ultrasound on blood vessels, especially endothelial cells (ECs) are still unclear. In this study, the laws of endothelial cytoskeleton changes under ultrasound induction are investigated. ECs are exposed to low-intensity ultrasound, and the cytoskeletal morphology is analyzed by a filamentous (F)-actin staining technique. We further analyze the characteristics of cytoskeleton rupture using indirect immunofluorescence techniques and cytoskeleton electron microscopy. Finally, the biological effects induced by ultrasound at the tissue level are investigated in an ex vivo blood-vessel model. Significant changes in cytoskeletal structure are detected when induced by ultrasound, including cytoskeletal rupture, blebbing and apoptosis. Moreover, a temporal threshold of ECs injury under different ultrasonic intensities is established. This study illustrates a pattern of significant changes in the cytoskeletal structure of ECs induced by ultrasound. The finding serves as a guide for selecting a safe threshold for clinical ultrasound applications.

Long Noncoding RNA Lx8-SINE B2 Interacts with Eno1 to Regulate Self-Renewal and Metabolism of Embryonic Stem Cells.

Long noncoding RNAs (lncRNAs) emerge as important orchestrators of biological processes in embryonic stem cells (ESCs). LncRNA Lx8-SINE B2 was recently identified as an ESC-specific lncRNA that marks pluripotency. Here, we studied the function of lncRNA Lx8-SINE B2 in ESCs. Depletion of Lx8-SINE B2 disrupted ESC proliferation, repressed the expression of pluripotency genes, activated differentiation genes, and inhibited reprogramming to induced pluripotent stem cells. The reduction of the colony formation ability of ESCs upon Lx8-SINE B2 knockdown was accompanied by the elongation of the G1 phase and the shortening of the S phase. Transcriptome analysis revealed that Lx8-SINE B2 deficiency affected multiple metabolic pathways, particularly glycolysis. Mechanistically, Lx8-SINE B2 functions as a cytoplasmic lncRNA and interacts with the glycolytic enzyme Eno1 as shown by RNA pull-down and RNA localization analysis. Lx8-SINE B2 and Eno1 interact with and regulate each other's expression, hence promoting the expression of metabolic genes and influencing glycolysis. In conclusion, we have identified lncRNA Lx8-SINE B2 as a novel regulator of ESC proliferation, cell cycle, and metabolism through working with Eno1.

Cabin air quality on non-smoking commercial flights: A review of published data on airborne pollutants.

We reviewed 47 documents published 1967-2019 that reported measurements of volatile organic compounds (VOCs) on commercial aircraft. We compared the measurements with the air quality standards and guidelines for aircraft cabins and in some cases buildings. Average levels of VOCs for which limits exist were lower than the permissible levels except for benzene with average concentration at 5.9 ± 5.5 µg/m3 . Toluene, benzene, ethylbenzene, formaldehyde, acetaldehyde, limonene, nonanal, hexanal, decanal, octanal, acetic acid, acetone, ethanol, butanal, acrolein, isoprene and menthol were the most frequently measured compounds. The concentrations of semi-volatile organic compounds (SVOCs) and other contaminants did not exceed standards and guidelines in buildings except for the average NO2 concentration at 12 ppb. Although the focus was on VOCs, we also retrieved the data on other parameters characterizing cabin environment. Ozone concentration averaged 38 ppb below the upper limit recommended for aircraft. The outdoor air supply rate ranged from 1.7 to 39.5 L/s per person and averaged 6.0 ± 0.8 L/s/p (median 5.8 L/s/p), higher than the minimum level recommended for commercial aircraft. Carbon dioxide concentration averaged 1315 ± 232 ppm, lower than what is permitted in aircraft and close to what is permitted in buildings. Measured temperatures averaged 23.5 ± 0.8°C and were generally within the ranges recommended for avoiding thermal discomfort. Relative humidity averaged 16% ± 5%, lower than what is recommended in buildings.

Zscan4c activates endogenous retrovirus MERVL and cleavage embryo genes.

Endogenous retroviruses (ERVs) contribute to ∼10 percent of the mouse genome. They are often silenced in differentiated somatic cells but differentially expressed at various embryonic developmental stages. A minority of mouse embryonic stem cells (ESCs), like 2-cell cleavage embryos, highly express ERV MERVL. However, the role of ERVs and mechanism of their activation in these cells are still poorly understood. In this study, we investigated the regulation and function of the stage-specific expressed ERVs, with a particular focus on the totipotency marker MT2/MERVL. We show that the transcription factor Zscan4c functions as an activator of MT2/MERVL and 2-cell/4-cell embryo genes. Zinc finger domains of Zscan4c play an important role in this process. In addition, Zscan4c interacts with MT2 and regulates MT2-nearby 2-cell/4-cell genes through promoting enhancer activity of MT2. Furthermore, MT2 activation is accompanied by enhanced H3K4me1, H3K27ac, and H3K14ac deposition on MT2. Zscan4c also interacts with GBAF chromatin remodelling complex through SCAN domain to further activate MT2 enhancer activity. Taken together, we delineate a previously unrecognized regulatory axis that Zscan4c interacts with and activates MT2/MERVL loci and their nearby genes through epigenetic regulation.

Hypoxia induced δ-Catenin to enhance mice hepatocellular carcinoma progression via Wnt signaling.

Hypoxia frequently occurs in solid tumors, hepatocellular carcinoma included. Hypoxia-inducible factors (HIFs) upregulated in hypoxia can induce various downstream target genes to resist hypoxia stress, resulting in tumor growth, angiogenesis and metastasis in vivo. Therefore, hypoxia associated genes are usually cancer progression associated genes and can be potential therapy targets for cancer therapy. In our present work, we find that the hypoxia-inducible transcriptional factor, HIF1α, can directly upregulate the expression of the gene Ctnnd2, which codes the protein δ-Catenin. Then, δ-Catenin can stabilize ß-Catenin by disrupting the destruction complex, which leads to the activation of Wnt signaling. As a result, δ-Catenin can promote the proliferation and migration of HCC cells in vitro, further enhance mice HCC tumorigenesis in vivo. In summary, our work reveals that δ-Catenin is a direct downstream target gene of HIF1α. It can activate Wnt signaling via ß-Catenin stabilization. δ-Catenin can enhance HCC progression.

Bacterial community in commercial airliner cabins in China.

Considering the amount of time that crew members and passengers spend on airliners and the potential health impact of pathogenic bacteria, it is important to understand the population of bacteria inside airliners and the factors affecting the bacterial concentration. This study recorded the species of airborne and cabin surface culturable bacteria inside various airliner. Seven flights ranging from 3 to 5 hours in duration on different types of airliner were chosen. Multiple species of bacteria in the air of the airliners, such as Brachybacterium paraconglomeratum, were identified by means of the 16S ribosomal RNA gene sequencing method, and most of the bacteria were Gram-positive. This study found that the bacterial concentration in the airliners decreases as the relative humidity increases. The decrease in the number of airborne bacteria may be the reason for the reduced occurrence of unwanted symptoms exhibited by passengers.

Defining the regulatory role of programmed cell death 4 in laryngeal squamous cell carcinoma.

Programmed cell death 4 (PDCD4) is decreased in many different kinds of malignant tumors. EMT endows tumor cells invasive and metastatic properties. However, few studies have determined the role of PDCD4 in the regulation of EMT in the context of laryngeal carcinoma. We examined the relationship between PDCD4 and EMT-associated proteins E-cadherin and N-cadherin using laryngeal carcinoma tissues. Gene manipulation was used to define the regulatory capacity of PDCD4. We report that PDCD4 and E-cadherin/N-cadherin expression were significantly changed in the carcinoma tissues, and their expression was associated with pathological grade, metastatic state, and clinical stage. The suppression of PDCD4 (and consequently, E-cadherin) was concomitant with increased proliferation and G2-phase arrest, decreased apoptosis, and increased cell invasion. PDCD4 upregulation reversed the above-mentioned results. In nude mice, PDCD4 knockdown increased tumor growth and pathological features, confirming the tumorigenic role of PDCD4. Finally, PDCD4 silencing was associated with dysregulation of the carcinogenic Wnt-ß-catenin and the STAT3-miR-21 signaling pathways. This study revealed a dynamic regulatory relationship between PDCD4 and critical factors for EMT, establishing a broad, functional role for PDCD4 in laryngeal carcinoma, which may be propagated by the STAT3-miR-21 pathway. These findings provide new information on an EMT-associated target that may lead to a novel therapy.

[Effect of epidermal growth factor and testosterone on androgen receptor activation in urethral plate fibroblasts in hypospadias].

OBJECTIVE: To investigate androgen receptor (AR) expression and the effect of epidermal growth factor (EGF) and testosterone on AR expression level.
 METHODS: EGF or different concentrations of testosterone were incubated with the primary urethral plate fibroblasts from patients with hypospadias. The levels of AR expression in the fibroblasts were detected by immunocytochemical assays and graphical analysis.
 RESULTS: There was no significant difference in AR activation under physiological concentrations (3×10(-8) mol/L) of testosterone between the control and the distal hypospadias group (P>0.05). However, there was a significant decrease in AR activation in the proximal hypospadias group compared to that in the control group (P<0.001). Under the concentration of 3×10(-6) mol/L, the effects of testosterone on AR activation were dramatically different in the three groups (control group>distal hypospadias group>proximal hypospadias group, P<0.001). AR activation level in the group of proximal hypospadias was improved most obviously when EGF and physiological concentration of testosterone were employed in the urethral plate fibroblasts from hypospadias patients (P<0.001), and it was improved more in the distal hypospadias group than that in the control group (P=0.02).
 CONCLUSION: AR expression and activation in the urethral plate fibroblasts from hypospadias patients are abnormal. EGF can be used to improve AR activation in fibroblasts from different types of hypospadias, especially in the proximal type.

Promoting protein crystallization using a plate with simple geometry.

Increasing the probability of obtaining protein crystals in crystallization screening is always an important goal for protein crystallography. In this paper, a new method called the cross-diffusion microbatch (CDM) method is presented, which aims to efficiently promote protein crystallization and increase the chance of obtaining protein crystals. In this method, a very simple crystallization plate was designed in which all crystallization droplets are in one sealed space, so that a variety of volatile components from one droplet can diffuse into any other droplet via vapour diffusion. Crystallization screening and reproducibility tests indicate that this method could be a potentially powerful technique in practical protein crystallization screening. It can help to obtain crystals with higher probability and at a lower cost, while using a simple and easy procedure.

Characteristics of disinfection byproducts from dissolved organic matter during chlor(am)ination of source water in Tibetan Plateau, China.

The Tibetan Plateau, a typical high-altitude area, is less affected by human activities such as industrial development, and the external pollution to water sources is extremely low. Then it is also an important source of water samples for exploring the molecular characteristics of precursors in the dissolved organic matter (DOM) of disinfection byproducts (DBPs) in drinking water. Research data on DBPs in drinking water on the Tibet Plateau remains insufficient, leading to uncertainty about DBP contamination in the area. This study explores the formation potential of 35 typical DBPs, including 6 trihalomethanes (THMs), 9 haloacetic acids (HAAs), 2 halogenated ketones (HKs), 9 nitrosamines (NAs), and 9 aromatic DBPs, during chlorination and chloramination of typical source water samples in the Tibet Plateau of China. Moreover, in order to further investigate the characteristics of the generation of DBPs, the molecular composition of DOM in the collected water samples was characterized by Fourier transform ion cyclotron resonance mass spectrometry. The findings reveal that, for chlorination and chloramination, the average concentration of the five classes of DBPs was ranked as follows (chlorination, chloramination): HAAs (268.1 µg/L, 54.2 µg/L) > THMs (44.0 µg/L, 2.0 µg/L) > HKs (0.7 µg/L, 1.8 µg/L) > NAs (26.5 ng/L, 74.6 ng/L) > Aromatics (20.4 ng/L, 19.5 ng/L). The dominant compounds in THMs, HAAs, and NAs are trichloromethane, dichloroacetic acid, trichloroacetic acid, and nitrosopyrrolidine, respectively. This study highlights a significant positive correlation between DBP generation and UV254, SUV254, and the double bond equivalents of DOM in the source water. It systematically elucidates DOM molecular composition characteristics and DBP formation potential in high-altitude water sources, shedding light on key factors influencing DBP generation at the molecular level in high-altitude areas.

Design, Synthesis, and Mode of Action of Thioacetamide Derivatives as the Algicide Candidate Based on Active Substructure Splicing Strategy.

Lakes and reservoirs worldwide are experiencing a growing problem with harmful cyanobacterial blooms (HCBs), which have significant implications for ecosystem health and water quality. Algaecide is an effective way to control HCBs effectively. In this study, we applied an active substructure splicing strategy for rapid discovery of algicides. Through this strategy, we first optimized the structure of the lead compound S5, designed and synthesized three series of thioacetamide derivatives (series A, B, C), and then evaluated their algicidal activities. Finally, compound A3 with excellent performance was found, which accelerated the process of discovering and developing new algicides. The biological activity assay data showed that A3 had a significant inhibitory effect on M. aeruginosa. FACHB905 (EC50 = 0.46 µM) and Synechocystis sp. PCC6803 (EC50 = 0.95 µM), which was better than the commercial algicide prometryn (M. aeruginosa. FACHB905, EC50 = 6.52 µM; Synechocystis sp. PCC6803, EC50 = 4.64 µM) as well as better than lead compound S5 (M. aeruginosa. FACHB905, EC50 = 8.80 µM; Synechocystis sp. PCC6803, EC50 = 7.70 µM). The relationship between the surface electrostatic potential, chemical reactivity, and global electrophilicity of the compounds and their activities was discussed by density functional theory (DFT). Physiological and biochemical studies have shown that A3 might affect the photosynthesis pathway and antioxidant system in cyanobacteria, resulting in the morphological changes of cyanobacterial cells. Our work demonstrated that A3 might be a promising candidate for the development of novel algicides and provided a new active skeleton for the development of subsequent chemical algicides.

High glucose induces apoptosis and suppresses proliferation of adult rat neural stem cells following in vitro ischemia.

BACKGROUND: Post-stroke hyperglycemia appears to be associated with poor outcome from stroke, greater mortality, and reduced functional recovery. Focal cerebral ischemia data support that neural stem cells (NSCs) play an important role in post-ischemic repair. Here we sought to evaluate the negative effects of hyperglycemia on the cellular biology of NSCs following anoxia, and to test whether high glucose affects NSC recovery from ischemic injury. RESULTS: In this study, we used immortalized adult neural stem cells lines and we induced in vitro ischemia by 6 h oxygen and glucose deprivation (OGD) in an anaerobic incubator. Reperfusion was performed by returning cells to normoxic conditions and the cells were then incubated in experimental medium with various concentrations of glucose (17.5, 27.75, 41.75, and 83.75 mM) for 24 h. We found that high glucose (≥27.75 mM) exposure induced apoptosis of NSCs in a dose-dependent manner after exposure to OGD, using an Annexin V/PI apoptosis detection kit. The cell viability and proliferative activity of NSCs following OGD in vitro, evaluated with both a Cell Counting kit-8 (CCK-8) assay and a 5-ethynyl-2'-deoxyuridine (EdU) incorporation assay, were inhibited by high glucose exposure. Cell cycle analysis showed that high glucose exposure increased the percentage of cells in G0/G1-phase, and reduced the percentage of cells in S-phase. Furthermore, high glucose exposure was found to significantly induce the activation of c-Jun N-terminal protein kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) and suppress extracellular signal-regulated kinase 1/2 (ERK1/2) activity. CONCLUSIONS: Our results demonstrate that high glucose induces apoptosis and inhibits proliferation of NSCs following OGD in vitro, which may be associated with the activation of JNK/p38 MAPK pathways and the delay of G1-S transition in the cells.

Sensitivity of lysozyme crystallization to minute variations in concentration.

It is well known that the crystallization of proteins is strongly dependent on the crystallization conditions, which are sometimes very sensitive to environmental disturbances. Parameters such as the concentration of precipitants or protein, pH, temperature and many others are known to affect the probability of crystallization, and the task of crystallizing a new protein often involves a trial-and-error test using numerous combinations of crystallization conditions. These crystallization parameters, such as the concentration of either the protein or the precipitant, are important because they directly affect the driving force of crystallization: the supersaturation of the solution. Although it is common sense that the concentration can affect the crystallization process, the sensitivity of the crystallization process to variations in the concentration has seldom been addressed. Owing to the difficulty of directly preparing solutions with very small concentration variations, it is hard to carry out an investigation of their effect on the crystallization process. In this paper, a simple but novel method for studying the effect of minute concentration variations on the success rate of protein crystallization is presented. By evaporating the crystallization droplet, a fine concentration gradient could be created. With this fine-tuned concentration gradient, it was possible to observe the effects of minute variations in the concentration or supersaturation on the crystallization. A very minor change in concentration (as low as 0.13% of the initial concentration, i.e. 0.026 mg ml(-1) for lysozyme and 0.052 mg ml(-1) for NaCl in the current study) or a very minor change in supersaturation (as small as 0.018) could cause a clear difference in the crystallization success rate, indicating that the crystallization of proteins is very sensitive to the concentration level. Such sensitive behaviour may be one reason for the poor reproducibility of protein crystallization.

Efficacy and safety of transarterial chemoembolization-lenvatinib sequential therapy for the treatment of hepatocellular carcinoma with portal vein tumor thrombus: a retrospective study.

Background: The efficacy of transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC) with portal vein tumor thrombus (PVTT) is limited. There are insufficient data on TACE-lenvatinib sequential therapy for HCC with PVTT. We aimed to assess the efficacy and safety of TACE-lenvatinib sequential therapy for the treatment of HCC and PVTT. Methods: We retrospectively reviewed 12 consecutive patients with HCC and PVTT who underwent TACE-lenvatinib sequential therapy between July 2018 and May 2021. Lenvatinib treatment was started 1 week after TACE at a dose of 8 or 12 mg daily depending on the patient weight. Follow-up examinations were performed at 4 week and then every 8 weeks after the first TACE procedure. Overall survival (OS), progression-free survival (PFS), objective response rate (ORR), disease control rate (DCR) and adverse events (AEs) were calculated. Survival curves of PFS and OS were estimated using the Kaplan-Meier method. Results: The median OS and PFS were 16.9 and 6.15 months, respectively. The ORR and DCR were 75% and 91.7%, respectively. The most common lenvatinib-related AE was hypertension (33.3%), and the most common TACE-related AE was elevated liver enzymes (100%). No treatment-related deaths or grade 4 events were observed. Conclusions: TACE-lenvatinib sequential therapy may be safe and well tolerated, and may improve OS and PFS for HCC patients with PVTT. Further randomized controlled trials with larger cohorts are needed to confirm its efficacy and safety.

Efficacy and safety of transcatheter arterial chemoembolization-lenvatinib sequential therapy for patients with unresectable hepatocellular carcinoma: a single-arm clinical study.

Background: Repeated transcatheter arterial chemoembolization (TACE) could cause ischemia of the tumor tissue and increases production of angiogenic factors in patients with hepatocellular carcinoma (HCC). Lenvatinib can inhibit the expression of angiogenic factors induced by ischemia after TACE and reduce angiogenesis and tumor recurrence. TACE-lenvatinib sequential therapy may improve clinical outcomes. There have been few investigations of TACE-lenvatinib sequential therapy for the treatment of unresectable HCC. We aimed to evaluate the efficacy and safety of TACE-lenvatinib sequential therapy for unresectable HCC. Methods: From May 2018 to May 2021, 53 consecutive patients who underwent TACE-lenvatinib sequential therapy were retrospectively reviewed. Of these, 30 patients who met the inclusion criteria were selected. Lenvatinib treatment started within 1 or 2 weeks after TACE at a dose of 8 or 12 mg once daily. Treatment response was assessed using dynamic magnetic resonance imaging (MRI) according to the modified response evaluation criteria in solid tumor (mRECIST). Blood tests were also performed at every response evaluation. Patients with complete response (CR) or partial response (PR) and stable disease (SD) received continuous lenvatinib therapy, and patients with progressive disease (PD) received repeated TACE. The progression-free survival (PFS), overall survival (OS), objective response rate (ORR), disease control rate (DCR), and adverse events (AEs) were calculated. Statistical analysis was performed using the Kaplan-Meier method. Results: The median age was 58.5±9.1 years, and 16.7% (5/30) of patients were female. A total of 12 patients were categorized as Barcelona Clinic Liver Cancer (BCLC) Stage B and 18 were BCLC Stage C. The mean follow-up time was 15.7 months. The ORR was 76.7% (23/30), and the DCR was 96.7% (29/30). The median PFS was 6.1 months, and the median OS was 20.7 months. The most common lenvatinib-related AE was rash, and the most common TACE-related AE was elevated aspartate aminotransferase (AST). No treatment-related mortality was observed. Conclusions: From our findings, TACE-lenvatinib sequential therapy may prolong OS and PFS in patients with unresectable HCC, and the side effects are acceptable. The efficacy and safety of the sequential therapy should be confirmed in multiple center randomized controlled trials (RCTs) with a large sample and sufficient follow-up period.