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PloS One 2024Development of novel biodosimetry assays and medical countermeasures is needed to obtain a level of radiation preparedness in the event of malicious or accidental mass...
Development of novel biodosimetry assays and medical countermeasures is needed to obtain a level of radiation preparedness in the event of malicious or accidental mass exposures to ionizing radiation (IR). For biodosimetry, metabolic profiling with mass spectrometry (MS) platforms has identified several small molecules in easily accessible biofluids that are promising for dose reconstruction. As our microbiome has profound effects on biofluid metabolite composition, it is of interest how variation in the host microbiome may affect metabolomics based biodosimetry. Here, we 'knocked out' the microbiome of male and female C57BL/6 mice (Abx mice) using antibiotics and then irradiated (0, 3, or 8 Gy) them to determine the role of the host microbiome on biofluid radiation signatures (1 and 3 d urine, 3 d serum). Biofluid metabolite levels were compared to a sham and irradiated group of mice with a normal microbiome (Abx-con mice). To compare post-irradiation effects in urine, we calculated the Spearman's correlation coefficients of metabolite levels with radiation dose. For selected metabolites of interest, we performed more detailed analyses using linear mixed effect models to determine the effects of radiation dose, time, and microbiome depletion. Serum metabolite levels were compared using an ANOVA. Several metabolites were affected after antibiotic administration in the tryptophan and amino acid pathways, sterol hormone, xenobiotic and bile acid pathways (urine) and lipid metabolism (serum), with a post-irradiation attenuative effect observed for Abx mice. In urine, dose×time interactions were supported for a defined radiation metabolite panel (carnitine, hexosamine-valine-isoleucine [Hex-V-I], creatine, citric acid, and Nε,Nε,Nε-trimethyllysine [TML]) and dose for N1-acetylspermidine, which also provided excellent (AUROC ≥ 0.90) to good (AUROC ≥ 0.80) sensitivity and specificity according to the area under the receiver operator characteristic curve (AUROC) analysis. In serum, a panel consisting of carnitine, citric acid, lysophosphatidylcholine (LysoPC) (14:0), LysoPC (20:3), and LysoPC (22:5) also gave excellent to good sensitivity and specificity for identifying post-irradiated individuals at 3 d. Although the microbiome affected the basal levels and/or post-irradiation levels of these metabolites, their utility in dose reconstruction irrespective of microbiome status is encouraging for the use of metabolomics as a novel biodosimetry assay.
Topics: Animals; Mice; Female; Male; Mice, Inbred C57BL; Radiation Exposure; Microbiota; Metabolomics; Metabolome; Radiation, Ionizing
PubMed: 38758927
DOI: 10.1371/journal.pone.0300883 -
Science Advances May 2024SUCROSE-NON-FERMENTING1-RELATED PROTEIN KINASE1 (SnRK1), a central plant metabolic sensor kinase, phosphorylates its target proteins, triggering a global shift from...
SUCROSE-NON-FERMENTING1-RELATED PROTEIN KINASE1 (SnRK1), a central plant metabolic sensor kinase, phosphorylates its target proteins, triggering a global shift from anabolism to catabolism. Molecular modeling revealed that upon binding of KIN10 to GEMINIVIRUS REP-INTERACTING KINASE1 (GRIK1), KIN10's activation T-loop reorients into GRIK1's active site, enabling its phosphorylation and activation. Trehalose 6-phosphate (T6P) is a proxy for cellular sugar status and a potent inhibitor of SnRK1. T6P binds to KIN10, a SnRK1 catalytic subunit, weakening its affinity for GRIK1. Here, we investigate the molecular details of T6P inhibition of KIN10. Molecular dynamics simulations and in vitro phosphorylation assays identified and validated the T6P binding site on KIN10. Under high-sugar conditions, T6P binds to KIN10, blocking the reorientation of its activation loop and preventing its phosphorylation and activation by GRIK1. Under these conditions, SnRK1 maintains only basal activity levels, minimizing phosphorylation of its target proteins, thereby facilitating a general shift from catabolism to anabolism.
Topics: Sugar Phosphates; Trehalose; Protein Serine-Threonine Kinases; Phosphorylation; Arabidopsis Proteins; Molecular Dynamics Simulation; Protein Binding; Arabidopsis; Binding Sites; Transcription Factors
PubMed: 38758793
DOI: 10.1126/sciadv.adn0895 -
Cell Reports May 2024Glucose has long been considered a primary energy source for synaptic function. However, it remains unclear to what extent alternative fuels, such as lactate/pyruvate,...
Glucose has long been considered a primary energy source for synaptic function. However, it remains unclear to what extent alternative fuels, such as lactate/pyruvate, contribute to powering synaptic transmission. By detecting individual release events in hippocampal synapses, we find that mitochondrial ATP production regulates basal vesicle release probability and release location within the active zone (AZ), evoked by single action potentials. Mitochondrial inhibition shifts vesicle release closer to the AZ center and alters the efficiency of vesicle retrieval by increasing the occurrence of ultrafast endocytosis. Furthermore, we uncover that terminals can use oxidative fuels to maintain the vesicle cycle during trains of activity. Mitochondria are sparsely distributed along hippocampal axons, and we find that terminals containing mitochondria display enhanced vesicle release and reuptake during high-frequency trains. Our findings suggest that mitochondria not only regulate several fundamental features of synaptic transmission but may also contribute to modulation of short-term synaptic plasticity.
PubMed: 38758651
DOI: 10.1016/j.celrep.2024.114218 -
Frontiers in Microbiology 2024Cryopreservation of semen can give full play to the reproductive advantages of male animals. However, in actual production, due to the poor frost resistance of sheep...
INTRODUCTION
Cryopreservation of semen can give full play to the reproductive advantages of male animals. However, in actual production, due to the poor frost resistance of sheep semen and the low conception rate, the promotion of sheep frozen semen is greatly hindered. Therefore, it is urgent to improve the frost resistance of semen to improve the quality of frozen semen. At present, most studies on improving the quality of frozen semen are based on the improvement of semen dilutions, and few studies on improving the freezing resistance of ram semen by feeding functional amino acids.
METHODS
Therefore, 24 Turpan black rams were divided into high antifreeze group (HF) and a low antifreeze group (LF) Each of these groups was further randomly divided into control and experimental subgroups. The control subgroup was fed a basal diet, while the experimental subgroup received an additional 12 g/d of -Cit supplementation based on the control group for a duration of 90 days.
RESULTS
The results showed that Following -Cit supplementation, the experimental group demonstrated significantly elevated sperm density and VSL (Velocity of straight line), T-AOC, GSH-Px, and NO levels in fresh semen compared to the control group ( < 0.01). After thawing, the experimental group exhibited significantly higher levels of T-AOC, GSH-Px, and NO compared to the control group ( < 0.01). Additionally, the HFT group, after thawing frozen semen, displayed significantly higher HK1 protein expression compared to the control group. The number of spermatogonia, spermatocytes, and sperm cells in the HFT group was significantly higher than that in the HFC group. Moreover, 16S rRNA sequence analysis showed that , and were significantly enriched in the rumen of the HFT group, while was significantly enriched in the HFC group. In the duodenum, , and were significantly enriched in the HFT group, whereas and were significantly enriched in the HFC group.
DISCUSSION
Under the conditions employed in this study, -Cit supplementation was found to enhance the intestinal flora composition in rams, thereby improving semen quality, enhancing the antifreeze performance of semen, and promoting the development of testicular spermatogenic cells.
PubMed: 38756735
DOI: 10.3389/fmicb.2024.1396796 -
Frontiers in Oncology 2024Stress-induced promoter-associated and antisense lncRNAs (si-paancRNAs) originate from a reservoir of oxidative stress (OS)-specific promoters via RNAPII...
Stress-induced promoter-associated and antisense lncRNAs (si-paancRNAs) originate from a reservoir of oxidative stress (OS)-specific promoters via RNAPII pausing-mediated divergent antisense transcription. Several studies have shown that the KDM7A divergent transcript gene (), which encodes a si-paancRNA, is overexpressed in some cancer types. However, the mechanisms of this overexpression and its corresponding roles in oncogenesis and cancer progression are poorly understood. We found that expression is correlated with highly aggressive cancer types and specific inherently determined subtypes (such as ductal invasive breast carcinoma (BRCA) basal subtype). Its regulation is determined by missense mutations in a subtype-specific context. transcribes several intermediate-sized ncRNAs and a full-length transcript, exhibiting distinct expression and localization patterns. Overexpression of upregulates TP53 protein expression and H2AX phosphorylation in nonmalignant fibroblasts, while in semi-transformed fibroblasts, OS superinduces KDM7A-DT expression in a TP53-dependent manner. KDM7A-DT knockdown and gene expression profiling in -missense mutated luminal A BRCA variant, where it is abundantly expressed, indicate its significant role in cancer pathways. Endogenous over-expression of KDM7A-DT inhibits DNA damage response/repair (DDR/R) via the TP53BP1-mediated pathway, reducing apoptosis and promoting G2/M checkpoint arrest. Higher expression in BRCA is associated with locus gain/amplification, higher histologic grade, aneuploidy, hypoxia, immune modulation scores, and activation of the c-myc pathway. Higher KDM7A-DT expression is associated with relatively poor survival outcomes in patients with luminal A or Basal subtypes. In contrast, it is associated with favorable outcomes in patients with HER2+ER- or luminal B subtypes. KDM7A-DT levels are coregulated with critical transcripts and proteins aberrantly expressed in BRCA, including those involved in DNA repair via non-homologous end joining and epithelial-to-mesenchymal transition pathway. In summary, and its si-lncRNA exhibit several intrinsic biological and clinical characteristics that suggest important roles in invasive BRCA and its subtypes. -defined mRNA and protein subnetworks offer resources for identifying clinically relevant RNA-based signatures and prospective targets for therapeutic intervention.
PubMed: 38756663
DOI: 10.3389/fonc.2024.1227151 -
Frontiers in Neurology 2024The optimal placement of a cochlear implant (CI) electrode inside the scala tympani compartment to create an effective electrode-neural interface is the base for a... (Review)
Review
The optimal placement of a cochlear implant (CI) electrode inside the scala tympani compartment to create an effective electrode-neural interface is the base for a successful CI treatment. The characteristics of an effective electrode design include (a) electrode matching every possible variation in the inner ear size, shape, and anatomy, (b) electrically covering most of the neuronal elements, and (c) preserving intra-cochlear structures, even in non-hearing preservation surgeries. Flexible electrode arrays of various lengths are required to reach an angular insertion depth of 680° to which neuronal cell bodies are angularly distributed and to minimize the rate of electrode scalar deviation. At the time of writing this article, the current scientific evidence indicates that straight lateral wall electrode outperforms perimodiolar electrode by preventing electrode tip fold-over and scalar deviation. Most of the available literature on electrode insertion depth and hearing outcomes supports the practice of physically placing an electrode to cover both the basal and middle turns of the cochlea. This is only achievable with longer straight lateral wall electrodes as single-sized and pre-shaped perimodiolar electrodes have limitations in reaching beyond the basal turn of the cochlea and in offering consistent modiolar hugging placement in every cochlea. For malformed inner ear anatomies that lack a central modiolar trunk, the perimodiolar electrode is not an effective electrode choice. Most of the literature has failed to demonstrate superiority in hearing outcomes when comparing perimodiolar electrodes with straight lateral wall electrodes from single CI manufacturers. In summary, flexible and straight lateral wall electrode type is reported to be gentle to intra-cochlear structures and has the potential to electrically stimulate most of the neuronal elements, which are necessary in bringing full benefit of the CI device to recipients.
PubMed: 38756216
DOI: 10.3389/fneur.2024.1348439 -
Journal of Animal Science and... May 2024Comprehending the patterns of alteration in boar semen quality and identifying effective nutritional interventions are crucial for enhancing the productivity of...
BACKGROUND
Comprehending the patterns of alteration in boar semen quality and identifying effective nutritional interventions are crucial for enhancing the productivity of commercial pig systems. This study aimed to examine the alteration in semen quality in boars, and assess the impact of protocatechuic acid (PCA) on semen quality during the phase of declining semen quality.
METHODS
In Exp. 1, a total of 38 Pig Improvement Company (PIC) boars were selected and their semen quality data were recorded from the age of 9 to 37 months. In Exp. 2, 18 PIC boars (28 months old) were randomly assigned into three groups (n = 6) and fed a basal diet, a basal diet containing 500 or 1,000 mg/kg PCA, respectively. The experiment lasted for 12 weeks.
RESULTS
The semen volume, concentration, and total number of spermatozoa in boars exhibited an increase from 9 to 19 months old and showed a significant linear decreased trend in 28, 24, and 22 months old. Sperm motility displayed an upward trajectory, reaching its peak at 20 months of age, and showed a significant linear decreased trend at 20 months old. Dietary supplementation of PCA demonstrated an effect to mitigate the decrease in semen volume, concentration of spermatozoa, total number of spermatozoa (P > 0.05), and significantly increased the sperm motility (P < 0.05). Moreover, supplementation of 1,000 mg/kg PCA significantly increased the sperm viability (P < 0.05). Analysis on cellular signaling pathways revealed that PCA restored serum testosterone levels and alleviated oxidative damage by upregulating the expression of HO-1, SOD2, and NQO1 in testicular stromal cells. Notably, PCA can enhance phosphorylation by selectively binding to AMP-activated protein kinase (AMPK) protein, thereby improving sperm mitochondrial function and augmenting sperm motility via PGC-1/Nrf1.
CONCLUSIONS
These data elucidated the pattern of semen quality variation in boars within the age range of 9 to 37 months old, and PCA has the potential to be a natural antioxidant to enhance sperm quality through modulation of the AMPK/PGC-1/Nrf1 signaling pathway.
PubMed: 38755656
DOI: 10.1186/s40104-024-01031-6 -
Communications Biology May 2024The hepatic acute-phase response is characterized by a massive upregulation of serum proteins, such as haptoglobin and serum amyloid A, at the expense of liver...
The hepatic acute-phase response is characterized by a massive upregulation of serum proteins, such as haptoglobin and serum amyloid A, at the expense of liver homeostatic functions. Although the transcription factor hepatocyte nuclear factor 4 alpha (HNF4A) has a well-established role in safeguarding liver function and its cistrome spans around 50% of liver-specific genes, its role in the acute-phase response has received little attention so far. We demonstrate that HNF4A binds to and represses acute-phase genes under basal conditions. The reprogramming of hepatic transcription during inflammation necessitates loss of HNF4A function to allow expression of acute-phase genes while liver homeostatic genes are repressed. In a pre-clinical liver organoid model overexpression of HNF4A maintained liver functionality in spite of inflammation-induced cell damage. Conversely, HNF4A overexpression potently impaired the acute-phase response by retaining chromatin at regulatory regions of acute-phase genes inaccessible to transcription. Taken together, our data extend the understanding of dual HNF4A action as transcriptional activator and repressor, establishing HNF4A as gatekeeper for the hepatic acute-phase response.
Topics: Hepatocyte Nuclear Factor 4; Acute-Phase Reaction; Animals; Liver; Transcriptome; Mice; Down-Regulation; Humans; Mice, Inbred C57BL; Male; Gene Expression Regulation
PubMed: 38755249
DOI: 10.1038/s42003-024-06288-1 -
ENeuro May 2024A hallmark of Parkinson's disease is the appearance of correlated oscillatory discharge throughout the cortico-basal ganglia (BG) circuits. In the primate globus...
A hallmark of Parkinson's disease is the appearance of correlated oscillatory discharge throughout the cortico-basal ganglia (BG) circuits. In the primate globus pallidus (GP), where the discharge of GP neurons is normally uncorrelated, pairs of GP neurons exhibit oscillatory spike correlations with a broad distribution of pairwise phase delays in experimental parkinsonism. The transition to oscillatory correlations is thought to indicate the collapse of the normally segregated information channels traversing the BG. The large phase delays are thought to reflect pathological changes in synaptic connectivity in the BG. Here we study the structure and phase delays of spike correlations measured from neurons in the mouse external GP (GPe) subjected to identical 1-100 Hz sinusoidal drive but recorded in separate experiments. First, we find that spectral modes of a GPe neuron's empirical instantaneous phase response curve (iPRC), elucidate at what phases of the oscillatory drive the GPe neuron locks when it is entrained, and the distribution of phases at which it spikes when it is not. Then, we show that in this case the pairwise spike cross-correlation equals the cross-correlation function of these spike phase distributions. Finally, we show that the distribution of GPe phase delays arises from the diversity of iPRCs, and is broadened when the neurons become entrained. Modeling GPe networks with realistic intranuclear connectivity demonstrates that the connectivity decorrelates GPe neurons without affecting phase delays. Thus, common oscillatory input gives rise to GPe correlations whose structure and pairwise phase delays reflect their intrinsic properties captured by their iPRCs. The external globus pallidus (GPe) is a hub in the basal ganglia, whose neurons impose a barrage of inhibitory synaptic currents on neurons of the subthalamic nucleus, substantia nigra and internal globus pallidus. GPe neurons normally fire independently, but in experimental parkinsonism, they become correlated in the frequency range associated with the pathological rhythms seen in human Parkinson's disease, raising the possibility that they may be generators of the pathological oscillation. We drove individual pallidal neurons with an oscillatory input over a wide range of frequencies. Cross-correlations of these neurons reproduced many of the features seen in parkinsonism, suggesting that their correlated oscillations might derive from a shared input rather than internal interconnections.
PubMed: 38755012
DOI: 10.1523/ENEURO.0187-24.2024 -
ENeuro May 2024Cholinergic neurons of the basal forebrain (BF) represent the main source of cholinergic innervation of large parts of the neocortex and are involved in adults in the...
Cholinergic neurons of the basal forebrain (BF) represent the main source of cholinergic innervation of large parts of the neocortex and are involved in adults in the modulation of attention, memory, and arousal. During the first postnatal days, they play a crucial role in the development of cortical neurons and cortical cytoarchitecture. However, their characteristics, during this period have not been studied. To understand how they can fulfill this role, we investigated the morphological and electrophysiological maturation of cholinergic neurons of the substantia innominata-nucleus basalis of Meynert complex (SI/NBM) in the perinatal period in mice. We show that cholinergic neurons, whether or not they express γ-aminobutyric acid (GABA) as a co-transmitter, are already functional at embryonic day 18 (E18). Until the end of the first postnatal week, they constitute a single population of neurons with a well-developed dendritic tree, a spontaneous activity including bursting periods, and a short latency response to depolarizations (early-firing). They are excited by both their GABAergic and glutamatergic afferents. During the second postnatal week, a second, less excitable, neuronal population emerges, with a longer delay response to depolarizations (late-firing), together with the hyperpolarizing action of GABAR-mediated currents. This classification into early-firing (40%) and late-firing (60%) neurons, is again independent of the co-expression of GABAergic markers. These results strongly suggest that during the first postnatal week, the specific properties of developing SI/NBM cholinergic neurons allow them to spontaneously release acetylcholine, or acetylcholine and GABA, into the developing cortex. During early postnatal days, basal forebrain cholinergic neurons from the substantia innominata-nucleus basalis of Meynert complex (SI/NBM) play a crucial role in cortical development. However, their morphological and electrophysiological characteristics have not been studied during this period. Here we show that perinatal SI/NBM cholinergic, whether they still/have co-expressed GABAergic markers, belong to a single, homogeneous population of spontaneously active, early-firing, bursting neurons, activated by both glutamatergic and GABAergic afferents until the GABARs-mediated current polarity shift from excitatory to inhibitory has occurred. This early high excitability suggests that they can release acetylcholine or acetylcholine and GABA into the developing cortical layers and fulfill their well-described role on the early development of cortical neurons and networks.
PubMed: 38755010
DOI: 10.1523/ENEURO.0538-23.2024