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Cell Reports Jun 2024Circadian rhythms are internal biological rhythms driving temporal tissue-specific, metabolic programs. Loss of the circadian transcription factor BMAL1 in the...
Circadian rhythms are internal biological rhythms driving temporal tissue-specific, metabolic programs. Loss of the circadian transcription factor BMAL1 in the paraventricular nucleus (PVN) of the hypothalamus reveals its importance in metabolic rhythms, but its functions in individual PVN cells are poorly understood. Here, loss of BMAL1 in the PVN results in arrhythmicity of processes controlling energy balance and alters peripheral diurnal gene expression. BMAL1 chromatin immunoprecipitation sequencing (ChIP-seq) and single-nucleus RNA sequencing (snRNA-seq) reveal its temporal regulation of target genes, including oxytocin (OXT), and restoring circulating OXT peaks in BMAL1-PVN knockout (KO) mice rescues absent activity rhythms. While glutamatergic neurons undergo day/night changes in expression of genes involved in cell morphogenesis, astrocytes and oligodendrocytes show gene expression changes in cytoskeletal organization and oxidative phosphorylation. Collectively, our findings show diurnal gene regulation in neuronal and non-neuronal PVN cells and that BMAL1 contributes to diurnal OXT secretion, which is important for systemic diurnal rhythms.
PubMed: 38935503
DOI: 10.1016/j.celrep.2024.114380 -
Cell Reports Jun 2024Mechanosensitive Piezo channels regulate cell division, cell extrusion, and cell death. However, systems-level functions of Piezo in regulating organogenesis remain...
Mechanosensitive Piezo channels regulate cell division, cell extrusion, and cell death. However, systems-level functions of Piezo in regulating organogenesis remain poorly understood. Here, we demonstrate that Piezo controls epithelial cell topology to ensure precise organ growth by integrating live-imaging experiments with pharmacological and genetic perturbations and computational modeling. Notably, the knockout or knockdown of Piezo increases bilateral asymmetry in wing size. Piezo's multifaceted functions can be deconstructed as either autonomous or non-autonomous based on a comparison between tissue-compartment-level perturbations or between genetic perturbation populations at the whole-tissue level. A computational model that posits cell proliferation and apoptosis regulation through modulation of the cutoff tension required for Piezo channel activation explains key cell and tissue phenotypes arising from perturbations of Piezo expression levels. Our findings demonstrate that Piezo promotes robustness in regulating epithelial topology and is necessary for precise organ size control.
PubMed: 38935502
DOI: 10.1016/j.celrep.2024.114398 -
JAMA Network Open Jun 2024The overutilization of antibiotics in very preterm infants (VPIs) at low risk of early-onset sepsis (EOS) is associated with increased mortality and morbidities....
IMPORTANCE
The overutilization of antibiotics in very preterm infants (VPIs) at low risk of early-onset sepsis (EOS) is associated with increased mortality and morbidities. Nevertheless, the association of early antibiotic exposure with bronchopulmonary dysplasia (BPD) remains equivocal.
OBJECTIVE
To evaluate the association of varying durations and types of early antibiotic exposure with the incidence of BPD in VPIs at low risk of EOS.
DESIGN, SETTING, AND PARTICIPANTS
This national multicenter cohort study utilized data from the Chinese Neonatal Network (CHNN) which prospectively collected data from January 1, 2019, to December 31, 2021. VPIs less than 32 weeks' gestational age or with birth weight less than 1500 g at low risk of EOS, defined as those born via cesarean delivery, without labor or rupture of membranes, and no clinical evidence of chorioamnionitis, were included. Data analysis was conducted from October 2022 to December 2023.
EXPOSURE
Early antibiotic exposure was defined as the total number of calendar days antibiotics were administered within the first week of life, which were further categorized as no exposure, 1 to 4 days of exposure, and 5 to 7 days of exposure.
MAIN OUTCOMES AND MEASURES
The primary outcome was the composite of moderate to severe BPD or mortality at 36 weeks' post menstrual age (PMA). Logistic regression was employed to assess factors associated with BPD or mortality using 2 different models.
RESULTS
Of the 27 176 VPIs included in the CHNN during the study period (14 874 male [54.7%] and 12 302 female [45.3%]), 6510 (23.9%; 3373 male [51.8%] and 3137 female [48.2.%]) were categorized as low risk for EOS. Among them, 1324 (20.3%) had no antibiotic exposure, 1134 (17.4%) received 1 to 4 days of antibiotics treatment, and 4052 (62.2%) received 5 to 7 days of antibiotics treatment. Of the 5186 VPIs who received antibiotics, 4098 (79.0%) received broad-spectrum antibiotics, 888 (17.1%) received narrow-spectrum antibiotics, and 200 (3.9%) received antifungals or other antibiotics. Prolonged exposure (5-7 days) was associated with increased likelihood of moderate to severe BPD or death (adjusted odds ratio [aOR], 1.23; 95% CI, 1.01-1.50). The use of broad-spectrum antibiotics (1-7 days) was also associated with a higher risk of moderate to severe BPD or death (aOR, 1.27; 95% CI, 1.04-1.55).
CONCLUSIONS AND RELEVANCE
In this cohort study of VPIs at low risk for EOS, exposure to prolonged or broad-spectrum antibiotics was associated with increased risk of developing moderate to severe BPD or mortality. These findings suggest that VPIs exposed to prolonged or broad-spectrum antibiotics early in life should be monitored for adverse outcomes.
Topics: Humans; Bronchopulmonary Dysplasia; Anti-Bacterial Agents; Infant, Newborn; Female; Male; Infant, Premature; Sepsis; China; Cohort Studies; Risk Factors; Incidence; Gestational Age; Infant, Very Low Birth Weight
PubMed: 38935376
DOI: 10.1001/jamanetworkopen.2024.18831 -
Amino Acids Jun 2024Exogenous polyamines, including putrescine (PUT), spermidine (SPD), and spermine (SPM), and the irreversible inhibitor of the rate-limiting enzyme ornithine...
Exogenous polyamines, including putrescine (PUT), spermidine (SPD), and spermine (SPM), and the irreversible inhibitor of the rate-limiting enzyme ornithine decarboxylase (ODC) of polyamine biosynthesis, α-difluoromethylornithine (DFMO), are implicated as stimulants for bone formation. We demonstrate in this study the osteogenic potential of exogenous polyamines and DFMO in human osteoblasts (hOBs), murine monocyte cell line RAW 264.7, and an ovariectomized rat model. The effect of polyamines and DFMO on hOBs and RAW 264.7 cells was studied by analyzing gene expression, alkaline phosphatase (ALP) activity, tartrate-resistant acid phosphatase (TRAP) activity, and matrix mineralization. Ovariectomized rats were treated with polyamines and DFMO and analyzed by micro computed tomography (micro CT). The mRNA level of the early onset genes of osteogenic differentiation, Runt-related transcription factor 2 (Runx2) and ALP, was significantly elevated in hOBs under osteogenic conditions, while both ALP activity and matrix mineralization were enhanced by exogenous polyamines and DFMO. Under osteoclastogenic conditions, the gene expression of both receptor activator of nuclear factor-κB (RANK) and nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1) was reduced, and TRAP activity was suppressed by exogenous polyamines and DFMO in RAW 264.7 cells. In an osteoporotic animal model of ovariectomized rats, SPM and DFMO were found to improve bone volume in rat femurs, while trabecular thickness was increased in all treatment groups. Results from this study provide in vitro and in vivo evidence indicating that polyamines and DFMO act as stimulants for bone formation, and their osteogenic effect may be associated with the suppression of osteoclastogenesis.
Topics: Animals; Mice; Osteoclasts; Osteogenesis; Rats; Humans; Cell Differentiation; Eflornithine; Female; Polyamines; Osteoblasts; RAW 264.7 Cells; Ovariectomy; Rats, Sprague-Dawley; Spermidine
PubMed: 38935136
DOI: 10.1007/s00726-024-03403-8 -
Investigative Ophthalmology & Visual... Jun 2024Retinal ganglion cells (RGCs) connect the retina to the brain. Proper development of the axons and dendrites of RGCs is the basis for these cells to function as...
PURPOSE
Retinal ganglion cells (RGCs) connect the retina to the brain. Proper development of the axons and dendrites of RGCs is the basis for these cells to function as projection neurons to deliver visual information to the brain. The purpose of this study was to investigate the function of Shtn1 (which encodes shootin1) in RGC neurite development.
METHODS
Immunofluorescence (IF) was used to characterize the expression pattern of marker genes. An in vitro direct somatic cell reprogramming system was used to generate RGC-like neurons (iRGCs), which was subsequently used to study the function of Shtn1. Short-hairpin RNAs (shRNAs) were used to knock down Shtn1, and the coding sequence (CDS) of Shtn1 was used to overexpress the gene. Lentiviruses were used to deliver shRNAs or CDSs into iRGCs. The patch clamp technique was used to measure the electrophysiological properties of the iRGCs. RNA sequencing (RNA-seq) was used to examine transcriptome expression.
RESULTS
Using IF, we demonstrated that shootin1 is distinctively expressed in RGCs during the period in which RGCs actively develop and adjust the connections of their neurites with upstream and downstream neurons. Using the iRGC system, we demonstrated that Shtn1 promotes the growth and complexity of neurites and thus the electrophysiological maturation, of iRGCs. RNA-seq analyses showed that Shtn1 may also regulate gene expression and neurogenesis in iRGCs.
CONCLUSIONS
Shtn1 promotes RGC neurite development. These findings improve our understanding of the molecular machinery governing RGC neurite development and may help to optimize future RGC regeneration methods.
Topics: Retinal Ganglion Cells; Animals; Neurites; Mice; Nerve Tissue Proteins; Cellular Reprogramming; Cells, Cultured; Mice, Inbred C57BL; Patch-Clamp Techniques; Neurogenesis
PubMed: 38935030
DOI: 10.1167/iovs.65.6.41 -
Frontiers in Neural Circuits 2024Various mammals have shown that sensory stimulation plays a crucial role in regulating the development of diverse structures, such as the olfactory bulb (OB), cerebral... (Review)
Review
Various mammals have shown that sensory stimulation plays a crucial role in regulating the development of diverse structures, such as the olfactory bulb (OB), cerebral cortex, hippocampus, and retina. In the OB, the dendritic development of excitatory projection neurons like mitral/tufted cells is influenced by olfactory experiences. Odor stimulation is also essential for the dendritic development of inhibitory OB interneurons, such as granule and periglomerular cells, which are continuously produced in the ventricular-subventricular zone throughout life. Based on the morphological and molecular features, OB interneurons are classified into several subtypes. The role for each interneuron subtype in the control of olfactory behavior remains poorly understood due to lack of each specific marker. Among the several OB interneuron subtypes, a specific granule cell subtype, which expresses the oncofetal trophoblast glycoprotein (Tpbg or 5T4) gene, has been reported to be required for odor detection and discrimination behavior. This review will primarily focus on elucidating the contribution of different granule cell subtypes, including the Tpbg/5T4 subtype, to olfactory processing and behavior during the embryonic and adult stages.
Topics: Animals; Interneurons; Olfactory Bulb; Humans; Neurogenesis
PubMed: 38933598
DOI: 10.3389/fncir.2024.1427378 -
Frontiers in Molecular Neuroscience 2024Rho guanine nucleotide exchange factors (Rho GEFs) activate Rho GTPases, which act as molecular switches regulating various essential cellular functions. This study...
Rho guanine nucleotide exchange factors (Rho GEFs) activate Rho GTPases, which act as molecular switches regulating various essential cellular functions. This study investigated the role of ARHGEF5, a Rho GEF known for its involvement in cell migration and invasion processes, in the context of brain development. We found that ARHGEF5 is essential for dendrite development during the early stages of neuronal growth. We also discovered that ARHGEF5 binds to Drebrin E, which is vital for coordinating actin and microtubule dynamics, and facilitates the interaction between Drebrin E and Cyclin-dependent kinase 5, which phosphorylates Drebrin E. Notably, ARHGEF5 deficiency resulted in a decrease in acetylated α-tubulin levels, and the expression of an α-tubulin acetylation mimetic mutant (K40Q) rescued the defects in dendrite development and neuronal migration, suggesting ARHGEF5's role in modulating microtubule stability. Additionally, ARHGEF5 was shown to influence Golgi positioning in the leading processes of migrating cortical neurons during brain development. Our study suggests that ARHGEF5 plays a crucial role in integrating cytoskeletal dynamics with neuronal morphogenesis and migration processes during brain development.
PubMed: 38932934
DOI: 10.3389/fnmol.2024.1421932 -
Viruses Jun 2024Honey bees () play a crucial role in agriculture through their pollination activities. However, they have faced significant health challenges over the past decades that...
Honey bees () play a crucial role in agriculture through their pollination activities. However, they have faced significant health challenges over the past decades that can limit colony performance and even lead to collapse. A primary culprit is the parasitic mite , known for transmitting harmful bee viruses. Among these viruses is deformed wing virus (DWV), which impacts bee pupae during their development, resulting in either pupal demise or in the emergence of crippled adult bees. In this study, we focused on DWV master variant B. DWV-B prevalence has risen sharply in recent decades and appears to be outcompeting variant A of DWV. We generated a molecular clone of a typical DWV-B strain to compare it with our established DWV-A clone, examining RNA replication, protein expression, and virulence. Initially, we analyzed the genome using RACE-PCR and RT-PCR techniques. Subsequently, we conducted full-genome RT-PCR and inserted the complete viral cDNA into a bacterial plasmid backbone. Phylogenetic comparisons with available full-length sequences were performed, followed by functional analyses using a live bee pupae model. Upon the transfection of in vitro-transcribed RNA, bee pupae exhibited symptoms of DWV infection, with detectable viral protein expression and stable RNA replication observed in subsequent virus passages. The DWV-B clone displayed a lower virulence compared to the DWV-A clone after the transfection of synthetic RNA, as evidenced by a reduced pupal mortality rate of only 20% compared to 80% in the case of DWV-A and a lack of malformations in 50% of the emerging bees. Comparable results were observed in experiments with low infection doses of the passaged virus clones. In these tests, 90% of bees infected with DWV-B showed no clinical symptoms, while 100% of pupae infected with DWV-A died. However, at high infection doses, both DWV-A and DWV-B caused mortality rates exceeding 90%. Taken together, we have generated an authentic virus clone of DWV-B and characterized it in animal experiments.
Topics: Animals; Bees; RNA Viruses; Phylogeny; Genome, Viral; Virus Replication; Pupa; Virulence; Varroidae; RNA, Viral
PubMed: 38932270
DOI: 10.3390/v16060980 -
Viruses May 2024In this study, we pioneered an alternative technology for manufacturing subunit influenza hemagglutinin (HA)-based vaccines. This innovative method involves harnessing...
In this study, we pioneered an alternative technology for manufacturing subunit influenza hemagglutinin (HA)-based vaccines. This innovative method involves harnessing the pupae of the Lepidoptera () as natural biofactories in combination with baculovirus vectors (using CrisBio technology). We engineered recombinant baculoviruses encoding two versions of the HA protein (trimeric or monomeric) derived from a pandemic avian H7N1 virus A strain (A/chicken/Italy/5093/99). These were then used to infect pupae, resulting in the production of the desired recombinant antigens. The obtained HA proteins were purified using affinity chromatography, consistently yielding approximately 75 mg/L of insect extract. The vaccine antigen effectively immunized poultry, which were subsequently challenged with a virulent H7N1 avian influenza virus. Following infection, all vaccinated animals survived without displaying any clinical symptoms, while none of the mock-vaccinated control animals survived. The CrisBio-derived antigens induced high titers of HA-specific antibodies in the vaccinated poultry, demonstrating hemagglutination inhibition activity against avian H7N1 and human H7N9 viruses. These results suggest that the CrisBio technology platform has the potential to address major industry challenges associated with producing recombinant influenza subunit vaccines, such as enhancing production yields, scalability, and the speed of development, facilitating the global deployment of highly effective influenza vaccines.
Topics: Animals; Influenza Vaccines; Pupa; Influenza in Birds; Vaccines, Subunit; Hemagglutinin Glycoproteins, Influenza Virus; Antibodies, Viral; Chickens; Influenza A Virus, H7N1 Subtype; Baculoviridae; Influenza A Virus, H7N9 Subtype; Humans; Vaccine Development; Moths; Pandemics
PubMed: 38932122
DOI: 10.3390/v16060829 -
Viruses May 2024Rotaviruses (RVs) are 11-segmented, double-stranded (ds) RNA viruses and important causes of acute gastroenteritis in humans and other animal species. Early RV particle... (Review)
Review
Rotaviruses (RVs) are 11-segmented, double-stranded (ds) RNA viruses and important causes of acute gastroenteritis in humans and other animal species. Early RV particle assembly is a multi-step process that includes the assortment, packaging and replication of the 11 genome segments in close connection with capsid morphogenesis. This process occurs inside virally induced, cytosolic, membrane-less organelles called viroplasms. While many viral and cellular proteins play roles during early RV assembly, the octameric nonstructural protein 2 (NSP2) has emerged as a master orchestrator of this key stage of the viral replication cycle. NSP2 is critical for viroplasm biogenesis as well as for the selective RNA-RNA interactions that underpin the assortment of 11 viral genome segments. Moreover, NSP2's associated enzymatic activities might serve to maintain nucleotide pools for use during viral genome replication, a process that is concurrent with early particle assembly. The goal of this review article is to summarize the available data about the structures, functions and interactions of RV NSP2 while also drawing attention to important unanswered questions in the field.
Topics: Rotavirus; Virus Assembly; Viral Nonstructural Proteins; Humans; Animals; Virus Replication; Genome, Viral; RNA, Viral; Capsid; RNA-Binding Proteins
PubMed: 38932107
DOI: 10.3390/v16060814