Actin polymerization inhibition by targeting ARPC2 affects intestinal stem cell homeostasis

Background

The rapid turnover of the intestinal epithelium is driven by the proliferation and differentiation of intestinal stem cells (ISCs). The dynamics of the F-actin cytoskeleton are critical for maintaining intercellular force and the signal transduction network. However, it remains unclear how direct interference with actin polymerization impacts ISC homeostasis. This study aims to reveal the regulatory effects of the F-actin cytoskeleton on the homeostasis of intestinal epithelium, as well as the potential risks of benproperine (BPP) as an anti-tumor drug.

Methods

Phalloidin fluorescence staining was utilized to test F-actin polymerization. Flow cytometry and IHC staining were employed to discriminate different types of intestinal epithelial cells. Cell proliferation was assessed through bromo-deoxyuridine (BrdU) and 5-ethynyl-2'-deoxyuridine (EdU) incorporation assays. The proliferation and differentiation of intestinal stem cells were replicated in vitro through organoid culture. Epithelial migration was evaluated through BrdU pulse labeling and chasing in mice.

Results

The F-actin content was observed to significantly increase as crypt cells migrated into the villus region. Additionally, actin polymerization in secretory cells, especially in Paneth cells (PCs), was much higher than that in neighboring ISCs. Treatment with the newly identified actin-related protein 2/3 complex subunit 2 (ARPC2) inhibitor BPP led to a dose-dependent increase or inhibition of intestinal organoid growth in vitro and crypt cell proliferation in vivo. Compared with the vehicle group, BPP treatment decreased the expression of Lgr5 ISC feature genes in vivo and in organoid culture. Meanwhile, PC differentiation derived from ISCs and progenitors was decreased by inhibition of F-actin polymerization. Mechanistically, BPP-induced actin polymerization inhibition may activate the Yes1-associated transcriptional regulator pathway, which affects ISC proliferation and differentiation. Accordingly, BPP treatment affected intestinal epithelial cell migration in a dose-dependent manner.

Conclusion

Our findings indicate that the regulation of cytoskeleton reorganization can affect ISC homeostasis. In addition, inhibiting ARPC2 with the Food and Drug Administration-approved drug BPP represents a novel approach to influencing the turnover of intestinal epithelial cells.

Minocycline improves autism-related behaviors by modulating microglia polarization in a mouse model of autism

Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental disorder with few pharmacological treatments. Minocycline, a tetracycline derivative that inhibits microglial activation, has been well-identified with anti-inflammatory properties and neuroprotective effects. A growing body of research suggests that ASD is associated with neuroinflammation, abnormal neurotransmitter levels, and neurogenesis. Thus, we hypothesized that minocycline could improve autism-related behaviors by inhibiting microglia activation and altering neuroinflammation. To verify our hypothesis, we used a mouse model of autism, BTBR T + Itpr3tf/J (BTBR). As expected, minocycline administration rescued the sociability and repetitive, stereotyped behaviors of BTBR mice while having no effect in C57BL/6J mice. We also found that minocycline improved neurogenesis and inhibited microglia activation in the hippocampus of BTBR mice. In addition, minocycline treatment inhibited Erk1/2 phosphorylation in the hippocampus of BTBR mice. Our findings show that minocycline administration alleviates ASD-like behaviors in BTBR mice and improves neurogenesis, suggesting that minocycline supplementation might be a potential strategy for improving ASD symptoms.

Chronic exposure to (2 R,6 R)-hydroxynorketamine induces developmental neurotoxicity in hESC-derived cerebral organoids

(R,S)-ketamine (ketamine) has been increasingly used recreationally and medicinally worldwide; however, it cannot be removed by conventional wastewater treatment plants. Both ketamine and its metabolite norketamine have been frequently detected to a significant degree in effluents, aquatic, and even atmospheric environments, which may pose risks to organisms and humans via drinking water and aerosols. Ketamine has been shown to affect the brain development of unborn babies, while it is still elusive whether (2 R,6 R)-hydroxynorketamine (HNK) induces similar neurotoxicity. Here, we investigated the neurotoxic effect of (2 R,6 R)-HNK exposure at the early stages of gestation by applying human cerebral organoids derived from human embryonic stem cells (hESCs). Short-term (2 R,6 R)-HNK exposure did not significantly affect the development of cerebral organoids, but chronic high-concentration (2 R,6 R)-HNK exposure at day 16 inhibited the expansion of organoids by suppressing the proliferation and augmentation of neural precursor cells (NPCs). Notably, the division mode of apical radial glia was unexpectedly switched from vertical to horizontal division planes following chronic (2 R,6 R)-HNK exposure in cerebral organoids. Chronic (2 R,6 R)-HNK exposure at day 44 mainly inhibited the differentiation but not the proliferation of NPCs. Overall, our findings indicate that (2 R,6 R)-HNK administration leads to the abnormal development of cortical organoids, which may be mediated by inhibiting HDAC2. Future clinical studies are needed to explore the neurotoxic effects of (2 R,6 R)-HNK on the early development of the human brain.

Doping of Cr to Regulate the Valence State of Cu and Co Contributes to Efficient Water Splitting

Water electrolysis in alkaline media is the most promising technology for hydrogen production, but efficient electrocatalysts are required to reduce the overpotential in HER and OER processes. In this work, the multicomponent transition metal catalyst Cr-Cu/CoO_x was loaded on copper foam by electrodeposition and annealing, and the catalyst exhibited excellent electrochemical activity. The HER overpotential is 21 mV and the OER overpotential is 252 mV at a current density of 10 mA cm^-2. The overall water splitting voltage is 1.51 V, even better than the Pt/C//RuO₂ two-electrode system (1.61 V). The excellent performance of this catalyst is mainly derived from the close synergistic interaction among Cu, Co, and Cr. The doping of Cr modulates the valence states of Cu and Co at the active sites and improves the adsorption of various reaction intermediates. Density functional theory (DFT) calculations show that the doping of Cr can optimize the adsorption of the reaction intermediate H*. Meanwhile, the high-valent Cr and Co promote hydrolysis through strong adsorption with OH^-. The present work provides a reasonable strategy for designing low-cost transition metals as efficient catalysts for water electrolysis.

AAV Delivery of shRNA Against TRPC6 in Mouse Hippocampus Impairs Cognitive Function

Transient Receptor Potential Canonical 6 (TRPC6) has been suggested to be involved in synapse function and contribute to hippocampal-dependent cognitive processes. Gene silencing of TRPC6 was performed by injecting adeno-associated virus (AAV) expressing TRPC6-specific shRNA (shRNA-TRPC6) into the hippocampal dentate gyrus (DG). Spatial learning, working memory and social recognition memory were impaired in the shRNA-TRPC6 treated mice compared to control mice after 4 weeks. In addition, gene ontology (GO) analysis of RNA-sequencing revealed that viral intervention of TRPC6 expression in DG resulted in the enrichment of the process of synaptic transmission and cellular compartment of synaptic structure. KEGG analysis showed PI3K-Akt signaling pathway were significantly down-regulated. Furthermore, the shRNA-TRPC6 treatment reduced dendritic spines of DG granule neurons, in terms of spine loss, the thin and mushroom types predominated. Accompanying the spine loss, the levels of PSD95, pAkt and CREB in the hippocampus were decreased in the shRNA-TRPC6 treated animals. Taken together, our results suggest that knocking down TRPC6 in the DG have a disadvantageous effect on cognitive processes.

Dexmedetomidine attenuates ethanol-induced inhibition of hippocampal neurogenesis in neonatal mice

BACKGROUND/AIMS

Ethanol (EtOH) exposure during a period comparable to the third trimester in human results in obvious neurotoxicity in the developing hippocampus and persistent deficits in hippocampal neurogenesis. Dexmedetomidine (DEX), a highly selective α-2-adrenergic agonist has been demonstrated to restore the impaired neurogenesis and neuronal plasticity in the dentate gyrus (DG) that follows neurological insult. However, the protective roles of DEX in the EtOH-induced deficits of postnatal neurogenesis in the hippocampus are still unknown.

METHODS

Mice were pretreated with DEX prior to EtOH exposure to determine its protective effects on impaired postnatal hippocampal neurogenesis. Six-day-old neonatal mice were treated with DEX (125 μg/kg) or saline, followed by EtOH at a total of 5 g/kg or an equivalent volume of saline on P7. Immunohistochemistry and immunofluorescence were used to evaluate the neurogenesis and activated microglia in the DG. Quantitative real time PCR (qRT-PCR) was utilized to assess the expression of inflammatory factors in the hippocampus.

RESULTS

DEX pretreatment attenuated the inhibition of EtOH-mediated hippocampal neurogenesis and the reduction of hippocampal neural precursor cells (NPCs). We further confirmed that DEX pretreatment reversed the EtOH-induced microglia activation in the DG as well as the upregulation of the hippocampal TNFα, MCP-1, IL-6, and IL-1β mRNA levels.

CONCLUSION

Our findings indicate that DEX pretreatment protects against EtOH-mediated inhibition of hippocampal neurogenesis in postnatal mice and reverses EtOH-induced neuroinflammation via repressing microglia activation and the expression of inflammatory cytokines.

Extracellular vesicles promote esophageal cancer progression by delivering lncZEB1-AS1 between cells

OBJECTIVE

To explore the expression of extracellular vesicle-derived lncZEB1-AS1 in esophageal cancer and its role in esophageal cancer progression.

PATIENTS AND METHODS

The extracellular vesicles (EVs) from esophageal cancer patients (n = 26) and normal subjects (n = 26) were isolated by differential centrifugation. The expression of lncZEB1-AS1 in EVs was detected by Real-time PCR (polymerase chain reaction). The clinical data of normal subjects and patients were analyzed. In addition, the concentration of EVs and lncZEB1-AS1 in blood samples from normal subjects and esophageal cancer patients were assessed. After co-culture of esophageal cancer cell line EC109 and EVs with or without lncZEB1-AS1 knockdown, cell proliferation was detected by CCK-8 assay. The possible target microRNAs of lncZEB1-AS1 in cytoplasm were predicted with miRcode, followed by correlation analysis of lncZEB1-AS1 and miR-214. Through literature review, lncZEB1-AS1 positively regulates ZEB1 expression, which was consistent with our result.

RESULTS

Quantitative Real-time PCR showed that the serum levels of EVs and the content of lncZEB1-AS1 in EVs from esophageal cancer patients were significantly higher than those in normal controls. LncZEB1-AS1 was overexpressed in esophageal cancer cells co-cultured with EVs of esophageal cancer patients. CCK-8 results indicated that EC109 cells co-cultured with EVs of esophageal cancer patients had stronger proliferative capacity. miRcode showed that miR-214 ranked the first of microRNAs that lncZEB1-AS1 might target, and miR-214 expression was significantly increased after lncZEB1-AS1 knockdown in EC109. After overexpressing lncZEB1-AS1 in EC109 or co-culturing EVs of esophageal cancer patients with EC109 cells, we found that lncZEB1-AS1 positively regulates ZEB1. In contrast, interfering with the expression of lncZEB1-AS1 in esophageal cancer cell lines can effectively reduce the expression of ZEB1.

CONCLUSIONS

EVs in the peripheral blood from esophageal cancer patients promote esophageal cancer progression by delivering lncZEB1-AS1 to esophageal cancer cells and targeting miR-214.

Effect of Elastic Modulus on the Accuracy of the Finite Element Method in Simulating Precision Glass Molding

Precision glass molding is a revolutionary technology for achieving high precision and efficient manufacturing of glass aspheric lenses. The material properties of glass, including elastic modulus and viscosity, are highly dependent on temperature fluctuations. This paper aims to investigate the effect of elastic modulus on the high-temperature viscoelasticity of glass and the accuracy of the finite element simulation of the molding process for glass aspheric lenses. The high-temperature elastic modulus of D-ZK3L glass is experimentally measured and combined with the glass cylinder compression creep curve to calculate the high temperature viscoelasticity of D-ZK3L. Three groups of viscoelastic parameters are obtained. Based on this, the molding process of the molded aspheric lens is simulated by the nonlinear finite element method (FEM). The surface curves of lenses obtained by simulation and theoretical analyses are consistent. The simulation results obtained at different initial elastic modulus values indicate that the elastic modulus has a great influence on the precision of the FEM-based molding process of glass aspheric lenses.

Effects of habitat fragmentation on the genetic diversity and differentiation of Dendrolimus punctatus (Lepidoptera: Lasiocampidae) in Thousand Island Lake, China, based on mitochondrial COI gene sequences

Thousand Island Lake (TIL) is a typical fragmented landscape and an ideal model to study ecological effects of fragmentation. Partial fragments of the mitochondrial cytochrome oxidase subunit I gene of 23 island populations of Dendrolimus punctatus in TIL were sequenced, 141 haplotypes being identified. The number of haplotypes increased significantly with the increase in island area and shape index, whereas no significant correlation was detected between three island attributes (area, shape and isolation) and haplotype diversity. However, the correlation with number of haplotypes was no longer significant when the 'outlier' island JSD (the largest island) was not included. Additionally, we found no significant relationship between geographic distance and genetic distance. Geographic isolation did not obstruct the gene flow among D. punctatus populations, which might be because of the high dispersal capacity of this pine moth. Fragmentation resulted in the conversion of large and continuous habitats into isolated, small and insular patches, which was the primary effect on the genetic diversity of D. punctatus in TIL. The conclusion to emphasize from our research is that habitat fragmentation reduced the biological genetic diversity to some extent, further demonstrating the importance of habitat continuity in biodiversity protection.

Citalopram restores short-term memory deficit and non-cognitive behaviors in APP/PS1 mice while halting the advance of Alzheimer's disease-like pathology

Alzheimer's disease (AD) is the most common cause of dementia. In addition to cognitive impairments, deficits in non-cognitive behaviors are also common neurological sequelae in AD. Here, we show that complex behavioral deficits in 7-month-old APPswe/PSEN1dE9 (APP/PS1) mice include impairments in object recognition, deficient social interaction, increased depression and buried marbles. Citalopram, one of the selective serotonin reuptake inhibitors (SSRIs), ameliorated the amyloid deposition in AD patients and transgenic animal models. After treatment for 4 weeks, citalopram rescued the deficits in short-term memory, sociability and depression in these mice. Further immunohistochemical analysis showed chronic citalopram treatment significantly attenuated β-amyloid deposition and microglial activation in the brains of APP/PS1 mice as demonstrated previously. Parvalbumin (PV) interneurons, which are the primary cellular subtype of GABAergic neurons and considered indispensable for short-term memory and social interaction, also contributed to the progress of depression. Additionally, we found the citalopram could significantly increase the PV-positive neurons in the cortex of APP/PS1 mice without alteration in the hippocampus, which might contribute to the improvement of behavioral performance. Our findings suggest that citalopram might be a potential candidate for the early treatment of AD.

USP4 inhibits p53 and NF-κB through deubiquitinating and stabilizing HDAC2

Histone deacetylases (HDACs) are major epigenetic modulators involved in a broad spectrum of human diseases including cancers. As HDACs are promising targets of cancer therapy, it is important to understand the mechanisms of HDAC regulation. In this study, we show that ubiquitin-specific peptidase 4 (USP4) interacts directly with and deubiquitinates HDAC2, leading to the stabilization of HDAC2. Accumulation of HDAC2 in USP4-overexpression cells leads to compromised p53 acetylation as well as crippled p53 transcriptional activation, accumulation and apoptotic response upon DNA damage. Moreover, USP4 targets HDAC2 to downregulate tumor necrosis factor TNFα-induced nuclear factor (NF)-κB activation. Taken together, our study provides a novel insight into the ubiquitination and stability of HDAC2 and uncovers a previously unknown function of USP4 in cancers.

Lentivirus-mediated knockdown of tumor protein D52-like 2 inhibits glioma cell proliferation

TPD52L2 (tumor protein D52-like 2) is a member of TPD52 family which has been implicated in multiple human cancers. Recently, TPD52 protein was shown to be associated with several malignancies, but very little is known about the function of TPD52L2 in cancers, especially in glioma to date, and its roles in glioma occurrence and progression remain to be elucidated. In the present study, we employed lentivirus-mediated RNA interference (RNAi) to knock down TPD52L2 expression in human glioma cell line U251. We found that knockdown of TPD52L2 significantly not only inhibited cell proliferation and colony formation, but also induced G0/G1 cell cycle arrest in vitro. Taken together, these findings suggest that TPD52L2 might play an important role in glioma tumorigenesis.

JNK phosphorylation promotes natural degeneration of cervical endplate chondrocytes by down-regulating expression of ANK

BACKGROUND

Endplate degeneration leads to accelerated degeneration of the intervertebral disc. The importance of endplate chondrocytes in this process is unclear. Many cellular processes in chondrocytes are controlled by activated c-Jun N-terminal kinases (JNK) and protein kinase B (AKT). However, the involvement of their pathways in the degeneration process needs to be elucidated.

AIM

To study activation of JNK and AKT signaling pathways and their significance for degeneration of endplate chondrocytes, as well as involvement of progressive ankylosis protein (ANK) in this process.

MATERIALS AND METHODS

Rat primary chondrocytes were grown to confluence and subcultured until passage 4. Morphological appearances (microscope, hematoxylin & eosin staining, toluidine blue staining) and proliferation rates of cells (MTT test) were observed. Further, levels of type II collagen, aggrecan, phosphorylated JNK and AKT, total JNK, AKT and ANK were evaluated by qPCR, flow cytometry and Western blot assays. Furthermore, inhibition experiments with SP600125, the JNK inhibitor, were carried out in the passage 4 cells to assess the effects of the JNK pathway on natural degeneration of endplate chondrocytes.

RESULTS

The proliferative speed of endplate chondrocytes progressively decreased during passaging. Expressions of type II collagen and aggrecan were significantly decreased with cells at higher passages. Furthermore, phosphorylation of JNK, but not AKT, was significantly up-regulated and accompanied by reduced ANK expression. Inhibition of the JNK pathway increased expression of type II collagen, aggrecan and ANK and facilitated proliferation rates.

CONCLUSIONS

Phosphorylation of JNK promotes natural degeneration of cervical endplate chondrocytes, likely by down-regulating ANK expression.

Contrast-enhanced ultrasound of hepatocellular carcinoma: Correlation of washout time and angiogenesis

BACKGROUND

The use of the pure blood pool ultrasound contrast agent SonoVue (Bracco, Italy) with specific ultrasound imaging software has enabled the dynamic visualization of tumor microcirculation.

AIM

The present study was designed to investigate the washout time of hepatocellular carcinoma (HCC) and correlate it with angiogenesis parameters.

METHODS

Thirty-one surgically confirmed HCC cases were prospectively evaluated with contrast-enhanced ultrasound (CEUS), and parameters such as wash-in time, peak enhancement time and washout time were determined offline. We also calculated microvessel density and the percentage of microvessel area (MVA) and compared CEUS parameters between a well differentiated group and a poorly to moderately differentiated group. The Spearman rank order correlation method was used to analyze the relationship between washout time and angiogenesis parameters.

RESULTS

The washout time was longer in well differentiated HCC patients compared to those with poorly to moderately differentiated HCC (p < 0.05). In addition, the washout time of HCC was positively correlated with the percentage of MVA (r = 0.510).

CONCLUSIONS

Given that the percentage of MVA was positively correlated with tumor blood volume, washout time may be associated with HCC blood volume.

Association of HLA genes with ankylosing spondylitis in Han population of eastern China

Ankylosing spondylitis (AS) is a chronic inflammatory disorder with a multifactorial genetic basis. HLA-B27 was reported with the greatest susceptibility to AS but did not act alone. The aim of this study was to search for other gene(s) associated with AS independently of HLA-B27 using 13 microsatellite markers spanning 1.5 Mb from locus TAP1 to HLA-Cw and a single-nucleotide polymorphism marker within NFkappaBIL1 gene promoter. Genotyping for microsatellites was performed in 175 AS patients of eastern Chinese and 219 ethnically matched healthy controls using polymerase chain reaction with fluorescence-labelled primers, whereas the SNP marker was genotyped by direct DNA sequencing. Allele as well as haplotype frequencies were compared between cases and controls, and a linkage disequilibrium analysis was performed to estimate the LD relationship between the candidate regions. The frequencies of alleles D6S2811*128, STR_MICA*A5.1 and D6S2672*109, as well as haplotypes D6S2811*128-D6S2927*213-D6S2810*340, D6S2927* 221-D6S2810*350-MICA*A5.1, and D6S2810*350-MICA*A5.1-D6S2800* 136 were significantly increased in B27-positive AS patients when compared with B27-positive controls. The results indicated that there may be other gene(s) within the HLA region, especially around locus HLA-B or HLA-Cw, with susceptibility to AS independently of HLA-B27.

Effects of a Single Nucleotide Polymorphism on the Expression of Human Tumor Necrosis Factor-alpha

Tumor necrosis factor (TNF)-alpha plays a prominent role in inflammations and is a proinflammatory cytokine that has been implicated in the pathogenesis of autoimmune and infectious diseases. Recent association studies have found that the TNF-alpha-857T allele was associated with several disorders. Here we demonstrate, with reporter genes under the control of the two allelic TNF-alpha promoters, that the minor allele -857T is a much stronger transcriptional activator than the major allele -857C in RAW264.7 cell line in response to lipopolysaccharide stimulation. However, the result was not consistent in HeLa cell line. Furthermore, for the quantitative analysis of TNF-alpha synthesis between the -857C/C genotype from healthy subjects and the -857C/T genotype from AS patients, the quantitative reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay were performed separately. There was no significant difference between the two groups at the level of mRNA and protein. These results show that this polymorphism may have a direct effect on TNF-alpha regulation in a tissue-specific manner, and apart from the polymorphism at -857 in the TNF-alpha promoter, there may be other factors affecting the expression of TNF-alpha.

Separation and determination of ephedrine alkaloids and tetramethylpyrazine in Ephedra sinica Stapf by gas chromatography-mass spectrometry

A simple, sensitive, and reliable method using gas chromatography (GC)-mass spectrometry (MS) is developed for the simultaneous determination of ephedrine alkaloids and 2,3,5,6-tetramethylpyrazine (TMP) in Ephedra sinica Stapf. The sample is extracted with ethyl ether and submitted to GC-MS for identification and quantitation without derivatization. The column used for GC is an HP-5 (30.0 m x 250 microm x 0.25 microm, 5% phenyl methyl siloxane), and the carrier gas is helium. The detection limits for ephedrine, pseudoephedrine, and TMP are 0.4 ng 0.7 ng, and 0.02 ng (signal-to-noise ratio of 3), respectively. The reproducibility of the total procedure is proved to be acceptable (RSD < 2%), and the recoveries are above 93%.

Analysis of tetramethylpyrazine in Ephedrae herba by gas chromatography-mass spectrometry and high-performance liquid chromatography

A simple and reliable HPLC method was developed for the determination of 2,3,5,6-tetramethylpyrazine (TMP) in Ephedrae herba. Further identification of TMP was achieved using GC-MS. The mobile phase used was methanol-water-35% acetic acid (35:65:0.5, v/v/v) at a flow-rate of 0.8 ml/min. The detection wavelength was set at 290 nm. The linear range of the peak area calibration curve of TMP was 2.64-264 mg/l (r=0.9987) and the recovery for TMP in Ephedrae herba extracts was 101.1-106.9%. The relative standard deviations of retention time and peak area were 0.18 and 1.5% (n=6), respectively. The detection limit of TMP was 0.03 mg/l. The contents of TMP in Ephedrae herba could easily be determined within 10 min.