To understand the mechanism(s) of age‐dependent outcomes of hepatitis B virus (HBV) infection in humans, we previously established an age‐related HBV mouse model in which 6‐week‐old (N6W) C3H/HeN ...mice exhibited virus tolerance whereas 12‐week‐old (N12W) counterparts presented virus clearance. By investigating the hepatic myeloid cell dynamics in mice of these two ages, we aim to identify factors associated with HBV clearance. C3H/HeN mice were transfected with an HBV plasmid by hydrodynamic injection. Serum HBV markers were monitored weekly. Hepatic leucocyte populations and their cytokine/chemokine productions were examined at baseline, day 3 (D3), day 7 (D7), and day 14 after injection. C‐C chemokine receptor type 2 (CCR2) antagonist and clodronate (CLD) were respectively administered to N12W and N6W mice to study the roles of lymphocyte antigen 6 complex, locus C (Ly6C)+ monocytes and Kupffer cells (KCs) in viral clearance. N12W mice had a significantly higher number of TNF‐α–secreting Ly6C+ monocytes and fewer IL‐10–secreting KCs at D3 in the liver than their younger N6W counterparts after HBV transfection. In addition, the elevated number of interferon‐γ+TNF‐α+ CD8+ T cells at D7 was only seen in the older cohort. The enhanced Ly6C+ monocyte induction in N12W mice resulted from elevated C‐C motif chemokine ligand 2 (CCL2) secretion by hepatocytes. CCR2 antagonist administration hampered Ly6C+ monocyte recruitment and degree of KC reduction and delayed HBV clearance in N12W animals. Depletion of KCs by CLD liposomes enhanced Ly6C+ monocyte recruitment and accelerated HBV clearance in N6W mice. Conclusions: Ly6C+ monocytes and KCs may, respectively, represent the resistance and tolerance arms of host defenses. These two cell types play an essential role in determining HBV clearance/tolerance. Manipulation of these cells is a promising avenue for immunotherapy of HBV‐related liver diseases.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Middle East respiratory syndrome coronavirus (MERS-CoV) consists of a positive-sense, single-stranded RNA genome and four structural proteins: the spike, envelope, membrane, and nucleocapsid protein. ...The assembly of the viral genome into virus particles involves viral structural proteins and is believed to be mediated through recognition of specific sequences and RNA structures of the viral genome.
A culture system for the production of MERS coronavirus-like particles (MERS VLPs) was determined and established by electron microscopy and the detection of coexpressed viral structural proteins. Using the VLP system, a 258-nucleotide RNA fragment, which spans nucleotides 19,712 to 19,969 of the MERS-CoV genome (designated PS258(19712-19969)
), was identified to function as a packaging signal. Assembly of the RNA packaging signal into MERS VLPs is dependent on the viral nucleocapsid protein. In addition, a 45-nucleotide stable stem-loop substructure of the PS258(19712-19969)
interacted with both the N-terminal domain and the C-terminal domain of the viral nucleocapsid protein. Furthermore, a functional SARS-CoV RNA packaging signal failed to assemble into the MERS VLPs, which indicated virus-specific assembly of the RNA genome.
A MERS-oV RNA packaging signal was identified by the detection of GFP expression following an incubation of MERS VLPs carrying the heterologous mRNA GFP-PS258(19712-19969)
with virus permissive Huh7 cells. The MERS VLP system could help us in understanding virus infection and morphogenesis.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The aqueous reprocessing of spent nuclear fuel generates a considerable amount of plutonium alongside contaminated stainless steel, necessitating meticulous handling for safe decommission and ...long‐term management. The present work investigated the co‐immobilization of CeO2 (as an inactive surrogate for PuO2) with metallic Fe and Cr (representing a simplified stainless steel) within a zirconolite ceramic wasteform, nominally targeting Ca1−xCexZrTi2−2xFexCrxO7. After sintering at 1400°C under an air atmosphere, the zirconolite phase constituted 90.8–95.1 wt.% of the product across the solid solution range of 0.05 ≤ x ≤ 0.25, alongside perovskite and baddeleyite secondary phases in varying proportion; no evidence of the unincorporated CeO2 or metallic and oxidized Fe or Cr were identified. Above x = 0.30 CeO2 was detected inferring, the solubility limit was reached. A polytype transformation from zirconolite 2M to 3T was confirmed by X‐ray diffraction and selected area electron diffraction results, with the relative fraction of the 3T phase gradually increasing to 49.5 wt.% at x = 0.30. Deconvolution of X‐ray photoelectron spectroscopy data revealed the partial reduction of Ce4+–Ce3+, whereas Fe and Cr species maintained trivalent, in agreement with the targeted substitution scheme. Benefitting from the excellent chemical flexibility of zirconolite structured compounds, the co‐immobilization approach may be an effective disposal pathway for Pu‐containing wastes and contaminated stainless steel residues.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The flower of Abelmoschus manihot L. is mainly used for the treatment of chronic kidney diseases, and has been reported to have bioactivities such as antioxidant, anti-inflammatory, antiviral, and ...antidepressant activities. This study used wild-type adult zebrafish as an animal model to elucidate the potential bioactivity of A. manihot flower ethanol extract (AME) in enhancing their sexual and reproductive functions. Zebrafish were fed AME twice a day at doses of 0.2%, 1%, and 10% for 28 days, and were then given the normal feed for an additional 14 days. The hormone 17-β estradiol was used as the positive control. Sexual behavioral parameters such as the number of times males chased female fish, the production of fertilized eggs, and the hatching rate of the fertilized eggs were recorded at days 0.33, 7, 14, 21, 28, and 42. The expression levels of sex-related genes—including lhcgr, ar, cyp19a1a, and cyp19a1b—were also examined. The results showed that the chasing number, fertilized egg production, and hatching rate were all increased with the increase in the AME treatment dose and treatment time. After feeding with 1% and 10% AME for 28 days, the chasing number in the treated group as compared to the control group increased by 1.52 times and 1.64 times, respectively; the yield of fertilized eggs increased by 1.59 times and 2.31 times, respectively; and the hatching rate increased by 1.26 times and 1.69 times, respectively. All three parameters exhibited strong linear correlations with one another (p < 0.001). The expression of all four genes was also upregulated with increasing AME dose and treatment duration. When feeding with 0.2%, 1%, and 10% AME for 28 days, the four sex-related genes were upregulated at ranges of 1.79−2.08-fold, 2.74−3.73-fold, and 3.30−4.66-fold, respectively. Furthermore, the effect of AME was persistent, as the promotion effect continued after the treatment was stopped for at least two weeks. The present findings suggest that AME can enhance the endocrine system and may improve libido and reproductive performance in zebrafish.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Antibiotic usage promotes intestinal colonization of antibiotic-resistant bacteria. However, whether resistant bacteria gain dominance in enteric microflora or disseminate to extraintestinal viscera ...remains unclear. Our aim was to investigate temporal diversity changes in microbiota and transepithelial routes of bacterial translocation after antibiotic-resistant enterobacterial colonization. Mice drinking water with or without antibiotics were intragastrically gavaged with ampicillin-resistant (Amp-r) nonpathogenic Escherichia coli (E. coli) and given normal water afterward. The composition and spatial distribution of intestinal bacteria were evaluated using 16S rDNA sequencing and fluorescence in situ hybridization. Bacterial endocytosis in epithelial cells was examined using gentamicin resistance assay and transmission electromicroscopy. Paracellular permeability was assessed by tight junctional immunostaining and measured by tissue conductance and luminal-to-serosal dextran fluxes. Our results showed that antibiotic treatment enabled intestinal colonization and transient dominance of orally acquired Amp-r E. coli in mice. The colonized Amp-r E. coli peaked on day 3 postinoculation and was competed out after 1 wk, as evidenced by the recovery of commensals, such as Escherichia, Bacteroides, Lachnospiraceae, Clostridium, and Lactobacillus. Mucosal penetration and extraintestinal dissemination of exogenous and endogenous enterobacteria were correlated with abnormal epithelial transcytosis but uncoupled with paracellular tight junctional damage. In conclusion, antibiotic-induced enteric dysbiosis predisposes to exogenous infection and causes systemic dissemination of both antibiotic-resistant and commensal enterobacteria through transcytotic routes across epithelial layers. These results may help explain the susceptibility to sepsis in antibiotic-resistant enteric bacterial infection.
Key points
Intestinal ischaemia causes epithelial death and crypt dysfunction, leading to barrier defects and gut bacteria‐derived septic complications.
Enteral glucose protects against ischaemic ...injury; however, the roles played by glucose metabolites such as pyruvate and ATP on epithelial death and crypt dysfunction remain elusive.
A novel form of necrotic death that involves the assembly and phosphorylation of receptor interacting protein kinase 1/3 complex was found in ischaemic enterocytes.
Pyruvate suppressed epithelial cell death in an ATP‐independent manner and failed to maintain crypt function. Conversely, replenishment of ATP partly restored crypt proliferation but had no effect on epithelial necroptosis in ischaemic gut.
Our data argue against the traditional view of ATP as the main cytoprotective factor by glucose metabolism, and indicate a novel anti‐necroptotic role of glycolytic pyruvate under ischaemic stress.
Mesenteric ischaemia/reperfusion induces epithelial death in both forms of apoptosis and necrosis, leading to villus denudation and gut barrier damage. It remains unclear whether programmed cell necrosis i.e. receptor‐interacting protein kinase (RIP)‐dependent necroptosis is involved in ischaemic injury. Previous studies have demonstrated that enteral glucose uptake by sodium‐glucose transporter 1 ameliorated ischaemia/reperfusion‐induced epithelial injury, partly via anti‐apoptotic signalling and maintenance of crypt proliferation. Glucose metabolism is generally assumed to be cytoprotective; however, the roles played by glucose metabolites (e.g. pyruvate and ATP) on epithelial cell death and crypt dysfunction remain elusive. The present study aimed to investigate the cytoprotective effects exerted by distinct glycolytic metabolites in ischaemic gut. Wistar rats subjected to mesenteric ischaemia were enterally instilled glucose, pyruvate or liposomal ATP. The results showed that intestinal ischaemia caused RIP1‐dependent epithelial necroptosis and villus destruction accompanied by a reduction in crypt proliferation. Enteral glucose uptake decreased epithelial cell death and increased crypt proliferation, and ameliorated mucosal histological damage. Instillation of cell‐permeable pyruvate suppressed epithelial cell death in an ATP‐independent manner and improved the villus morphology but failed to maintain crypt function. Conversely, the administration of liposomal ATP partly restored crypt proliferation but did not reduce epithelial necroptosis and histopathological injury. Lastly, glucose and pyruvate attenuated mucosal‐to‐serosal macromolecular flux and prevented enteric bacterial translocation upon blood reperfusion. In conclusion, glucose metabolites protect against ischaemic injury through distinct modes and sites, including inhibition of epithelial necroptosis by pyruvate and the promotion of crypt proliferation by ATP.
Key points
Intestinal ischaemia causes epithelial death and crypt dysfunction, leading to barrier defects and gut bacteria‐derived septic complications.
Enteral glucose protects against ischaemic injury; however, the roles played by glucose metabolites such as pyruvate and ATP on epithelial death and crypt dysfunction remain elusive.
A novel form of necrotic death that involves the assembly and phosphorylation of receptor interacting protein kinase 1/3 complex was found in ischaemic enterocytes.
Pyruvate suppressed epithelial cell death in an ATP‐independent manner and failed to maintain crypt function. Conversely, replenishment of ATP partly restored crypt proliferation but had no effect on epithelial necroptosis in ischaemic gut.
Our data argue against the traditional view of ATP as the main cytoprotective factor by glucose metabolism, and indicate a novel anti‐necroptotic role of glycolytic pyruvate under ischaemic stress.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Major depressive disorder (MDD) is a common neuropsychiatric disorder affecting the mood and mental well-being. Its pathophysiology remains elusive due to the complexity and heterogeneity of this ...disorder that affects millions of individuals worldwide. Chronic stress is frequently cited as the one of the risk factors for MDD. To date, the conventional monoaminergic theory (serotonin, norepinephrine, and/or dopamine dysregulation) has received the most attention in the treatment of MDD, and all available classes of antidepressants target these monoaminergic systems. However, the contributions of other neurotransmitter systems in MDD have been widely reported. Emerging preclinical and clinical findings reveal that maladaptive glutamatergic neurotransmission might underlie the pathophysiology of MDD, thus revealing its critical role in the neurobiology of MDD and as the therapeutic target. Aiming beyond the monoaminergic hypothesis, studies of the neurobiological mechanisms underlying the stress-induced impairment of AMPA (a-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid)-glutamatergic neurotransmission in the brain could provide novel insights for the development of a new generation of antidepressants without the detrimental side effects. Here, the authors reviewed the recent literature focusing on the role of AMPA-glutamatergic neurotransmission in stress-induced maladaptive responses in emotional and mood-associated brain regions, including the hippocampus, amygdala, prefrontal cortex, nucleus accumbens and periaqueductal gray.
Alteration of neuropeptide Y (NPY) in serum may cause sleep disturbance, circadian rhythm disorder, and/or even emotional illness. γ-Aminobutyric acid (GABA) is an inhibitory neurotransmitter and has ...been widely used for reduction of depression, anxiety, and/or psychological stress since it can raise the total or parasympathetic nerve activities in the mammalian central nervous system. However, drawbacks including short half-life in vivo and low absorption efficiency make synthetic GABA less usability in drug formulation, while it is more effective to uptake GABA through long term/regular daily diet. In this study, we successfully produced GABA-enriched rice by inoculating grain seeds of Taiwanese rice with
Bacillus amyloliquefaciens
(
B. amyloliquefaciens
) during germination, and demonstrated that the
B. amyloliquefaciens
-inoculated rice (BAR) can grow with a normal root/sprout length but significantly increased germination ratio compared to the rice without
B. amyloliquefaciens
treatment
.
Based on the animal study in association with the hole board test, our data showed that the level of serum NPY as well as the number of head-dips of the mice treated with the BAR for 8 days significantly enhanced 2 folds (
P
< 0.01) compared to the mice without GABA, but such BAR-induced efficacies dramatically vanished as their gastrointestinal GABA
B
receptor and/or vagus nerves were removed through use of GABA receptor antagonist or vagotomy, respectively. These results manifested the potential of the BAR on anxiolytic applications and unveiled likely mediators for GABA-induced anxiolytic activity.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The rearranged during transfection (RET) receptor tyrosine kinase plays a key role in transducing signals related to cell growth and differentiation.
mutant mice show abnormal retinal activity and ...abnormal levels and morphology of bipolar cells, yet die on the 21
day after birth as a result of renal underdevelopment. To extend the observation period, we generated the
conditional knockout
mouse model and analyzed the retinal function and morphological changes in mature and aging
mice.
Retina-specific depletion of
was achieved using mice with floxed alleles of the
gene with CHX10-driven Cre recombinase; floxed mice without Cre expression were used as controls. Retinal function was examined using electroretinography (ERG), and 2-, 4-, 12-, and 24-month-old mice were analyzed by hematoxylin staining and immunohistochemistry to evaluate retinal morphological alterations. The ultrastructure of photoreceptor synapses was evaluated using electron microscopy.
The results of the ERG testing showed that b-wave amplitudes were reduced in
mice, whereas a-waves were not affected. A histopathological analysis revealed a thinner and disorganized outer plexiform layer at the ages of 12 and 24 months in
mice. Moreover, the data provided by immunohistochemistry showed defects in the synapses of photoreceptor cells. This result was confirmed at the ultrastructural level, thus supporting the participation of
in the morphological changes of the synaptic ribbon.
Our results provide evidence of the role of
in maintaining the function of the retina, which was essential for preserving the structure of the synaptic ribbon and supporting the integrity of the outer plexiform layer.
Enduring exposure to psychological stress is associated with an elevated risk of major depressive disorder (MDD). There is an enormous need to investigate the unexplored mechanisms of MDD. We ...examined whether pain-free stress alters synaptic transmission, causing depression-like behaviors in the ventrolateral periaqueductal gray (vlPAG), a brain stem nucleus that controls stress-related depression-like behavior.
In the current study, we studied neuronal changes in the vlPAG and behavioral transforms using electrophysiological recordings, behavioral tests, and pharmacological approaches.
We found that chronic restraint stress (CRS) diminished glutamatergic transmission in the vlPAG, leading to maladaptive behavioral despair and anhedonia in mice demonstrated by the forced swimming test (FST), tail suspension test (TST) and female urine sniffing test (FUST). Moreover, CRS increased behavioral hypersensitivity shown by the von Frey test. Bath perfusion with the rapid-acting antidepressant (2R,6R)-hydroxynorketamine (HNK) increased both the frequency and amplitude of miniature excitatory postsynaptic currents (mEPSCs) in vlPAG neurons in the CRS and control groups. Functionally, (2R,6R)-HNK directly enhanced the action potential firing rate in vlPAG neurons. Behaviorally, intravlPAG microinjection of (2R,6R)-HNK alleviated chronic restraint stress-induced depression-like behaviors and behavioral hypersensitivity.
These results demonstrate that psychological stress-elicited depression-like behavior is related to a remarkable decrease in glutamatergic transmission in the vlPAG. The maladaptive behaviors are attributed to hypoactivity of glutamatergic neurons in the vlPAG, and direct enhancement of glutamatergic neuronal activity in the vlPAG rescues depression-like behaviors. The present results prove that vlPAG is critical for controlling stress-induced depression-like behaviors through alteration of glutamatergic transmission.
•Ventrolateral PAG controls chronic psychological stress-elicited depression-like behavior.•Chronic restraint stress diminishes glutamatergic transmission in the vlPAG.•(2R,6R)-hydroxynorketamine increases neuronal activity in the vlPAG.•(2R,6R)-hydroxynorketamine in the vlPAG rescues restraint stress-elicited depression-like behavior.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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