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ENeuro Jun 2024Preparing acute brain slices produces trauma that mimics severe penetrating brain injury. In neonatal acute brain slices, the spatiotemporal characteristics of...
Preparing acute brain slices produces trauma that mimics severe penetrating brain injury. In neonatal acute brain slices, the spatiotemporal characteristics of trauma-induced calcium dynamics in neurons and its effect on network activity are relatively unknown. Using multiphoton laser scanning microscopy of the somatosensory neocortex in acute neonatal mouse brain slices (P8-12), we simultaneously imaged neuronal Ca dynamics (GCaMP6s) and cytotoxicity (propidium iodide or PI) to determine the relationship between cytotoxic Ca loaded neurons (GCaMP-filled) and cell viability at different depths and incubation times. PI-cells and GCaMP-filled neurons were abundant at the surface of the slices, with an exponential decrease with depth. Regions with high PI-cells correlated with elevated neuronal and neuropil Ca The number of PI-cells and GCaMP-filled neurons increased with prolonged incubation. GCaMP-filled neurons did not participate in stimulus-evoked or seizure-evoked network activity. Significantly, the superficial tissue, with a higher degree of trauma-induced injury, showed attenuated seizure-related neuronal Ca responses. Calpain inhibition prevented the increase in PI-cells and GCaMP-filled neurons in the deep tissue and during prolonged incubation times. Isoform-specific pharmacological inhibition implicated calpain-2 as a significant contributor to trauma-induced injury in acute slices. Our results show a calpain-mediated spatiotemporal relationship between cell death and aberrant neuronal Ca load in acute neonatal brain slices. Also, we demonstrate that neurons in acute brain slices exhibit altered physiology depending on the degree of trauma-induced injury. Blocking calpains may be a therapeutic option to prevent acute neuronal death during traumatic brain injury in the young brain. This is the first study to characterize the spatiotemporal dynamics of neocortical injury in acute neonatal slices, mimicking severe penetrating traumatic brain injury, using PI labeling and elevated neuronal Ca load as markers for cytotoxicity. We found depth- and time-dependent neuronal damage, leading to altered neuronal responses. Elevate neuronal Ca and cytotoxicity were mitigated by pharmacologically inhibiting calpains, a family of Ca-dependent proteases involved in multiple cell death mechanisms. Our study provides evidence for injury-dependent neuronal and circuit function alterations in neonatal acute brain slices. Calpain inhibition decreased trauma-induced cell death in the neonatal brain, identifying them as potential therapeutic targets at this age.
PubMed: 38886064
DOI: 10.1523/ENEURO.0007-24.2024 -
Life Science Alliance Sep 2024The unfolded protein response can switch from a pro-survival to a maladaptive, pro-apoptotic mode. During ER stress, IRE1α sensors dimerize, become phosphorylated, and...
The unfolded protein response can switch from a pro-survival to a maladaptive, pro-apoptotic mode. During ER stress, IRE1α sensors dimerize, become phosphorylated, and activate XBP1 splicing, increasing folding capacity in the ER protein factory. The steps that turn on the IRE1α endonuclease activity against endogenous mRNAs during maladaptive ER stress are still unknown. Here, we show that although necessary, IRE1α dimerization is not sufficient to trigger phosphorylation. Random and/or guided collisions among IRE1α dimers are needed to elicit cross-phosphorylation and endonuclease activities. Thus, reaching a critical concentration of IRE1α dimers in the ER membrane is a key event. Formation of stable IRE1α clusters is not necessary for RNase activity. However, clustering could modulate the potency of the response, promoting interactions between dimers and decreasing the accessibility of phosphorylated IRE1α to phosphatases. The stepwise activation of IRE1α molecules and their low concentration at the steady state prevent excessive responses, unleashing full-blown IRE1 activity only upon intense stress conditions.
Topics: Endoribonucleases; Phosphorylation; Protein Serine-Threonine Kinases; Humans; Endoplasmic Reticulum Stress; Protein Multimerization; Unfolded Protein Response; Endoplasmic Reticulum; Ribonucleases
PubMed: 38886017
DOI: 10.26508/lsa.202302562 -
PLoS Pathogens Jun 2024Candida albicans is a leading cause of intravascular catheter-related infections. The capacity for biofilm formation has been proposed to contribute to the persistence...
Candida albicans is a leading cause of intravascular catheter-related infections. The capacity for biofilm formation has been proposed to contribute to the persistence of this fungal pathogen on catheter surfaces. While efforts have been devoted to identifying microbial factors that modulate C. albicans biofilm formation in vitro, our understanding of the host factors that may shape C. albicans persistence in intravascular catheters is lacking. Here, we used multiphoton microscopy to characterize biofilms in intravascular catheters removed from candidiasis patients. We demonstrated that, NETosis, a type of neutrophil cell death with antimicrobial activity, was implicated in the interaction of immune cells with C. albicans in the catheters. The catheter isolates exhibited reduced filamentation and candidalysin gene expression, specifically in the total parenteral nutrition culture environment. Furthermore, we showed that the ablation of candidalysin expression in C. albicans reduced NETosis and conferred resistance to neutrophil-mediated fungal biofilm elimination. Our findings illustrate the role of neutrophil NETosis in modulating C. albicans biofilm persistence in an intravascular catheter, highlighting that C. albicans can benefit from reduced virulence expression to promote its persistence in an intravascular catheter.
PubMed: 38885290
DOI: 10.1371/journal.ppat.1012319 -
PLoS Genetics Jun 2024Very little is known about the process of meiosis in the apicomplexan parasite Cryptosporidium despite the essentiality of sex in its life cycle. Most cell lines only...
Very little is known about the process of meiosis in the apicomplexan parasite Cryptosporidium despite the essentiality of sex in its life cycle. Most cell lines only support asexual growth of Cryptosporidium parvum (C. parvum), but stem cell derived intestinal epithelial cells grown under air-liquid interface (ALI) conditions support the sexual cycle. To examine chromosomal dynamics during meiosis in C. parvum, we generated two transgenic lines of parasites that were fluorescently tagged with mCherry or GFP on chromosomes 1 or 5, respectively. Infection of ALI cultures or Ifngr1-/- mice with mCherry and GFP parasites resulted in cross-fertilization and the formation of "yellow" oocysts, which contain 4 haploid sporozoites that are the product of meiosis. Recombinant oocysts from the F1 generation were purified and used to infect HCT-8 cultures, and phenotypes of the progeny were observed by microscopy. All possible phenotypes predicted by independent segregation were represented equally (~25%) in the population, indicating that C. parvum chromosomes exhibit a Mendelian inheritance pattern. The most common pattern observed from the outgrowth of single oocysts included all possible parental and recombinant phenotypes derived from a single meiotic event, suggesting a high rate of crossover. To estimate the frequency of crossover, additional loci on chromosomes 1 and 5 were tagged and used to monitor intrachromosomal crosses in Ifngr1-/- mice. Both chromosomes showed a high frequency of crossover compared to other apicomplexans with map distances (i.e., 1% recombination) of 3-12 kb. Overall, a high recombination rate may explain many unique characteristics observed in Cryptosporidium spp. such as high rates of speciation, wide variation in host range, and rapid evolution of host-specific virulence factors.
PubMed: 38885280
DOI: 10.1371/journal.pgen.1011162 -
PloS One 2024In this study, a simple calcination route was adopted to prepare hausmannite Mn3O4 nanoparticles using rice powder as soft bio-template. Prepared Mn3O4 was characterized...
In this study, a simple calcination route was adopted to prepare hausmannite Mn3O4 nanoparticles using rice powder as soft bio-template. Prepared Mn3O4 was characterized by Fourier Transform Infra-Red Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray microanalysis (EDX), Powder X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Brunauer-Emmett-Teller (BET) and Solid state UV-Vis spectroscopic techniques. Mn-O stretching in tetrahedral site was confirmed by FTIR and Raman spectra. % of Mn and O content supported Mn3O4 formation. The crystallinity and grain size was found to be 68.76% and 16.43 nm, respectively; tetragonal crystal system was also cleared by XRD. TEM clarified the planes of crystal formed which supported the XRD results and BET demonstrated mesoporous nature of prepared Mn3O4 having low pore volume. Low optical band gap of 3.24 eV of prepared Mn3O4 nanoparticles indicated semiconductor property and was used as cathode material to fabricate CR-2032 coin cell of Aqueous Rechargeable Zinc Ion Battery (ARZIB). A reversible cyclic voltammogram (CV) showed good zinc ion storage performance. Low cell resistance was confirmed by Electrochemical Impedance Spectroscopy (EIS). The coin cell delivered high specific discharge capacity of 240.75 mAhg-1 at 0.1 Ag-1 current density. The coulombic efficiency was found to be 99.98%. It also delivered excellent capacity retention 94.45% and 64.81% after 300 and 1000 charge-discharge cycles, respectively. This work offers a facile and cost effective approach for preparing cathode material of ARZIBs.
Topics: Oryza; Manganese Compounds; Electric Power Supplies; Zinc; Oxides; Powders; Nanoparticles; X-Ray Diffraction; Spectroscopy, Fourier Transform Infrared
PubMed: 38885268
DOI: 10.1371/journal.pone.0305611 -
PloS One 2024This study aimed to develop a novel Gelatin silver oxide material for releasing nitric oxide bionanocomposite wound dressing with enhanced mechanical, chemical, and...
This study aimed to develop a novel Gelatin silver oxide material for releasing nitric oxide bionanocomposite wound dressing with enhanced mechanical, chemical, and antibacterial properties for the treatment of diabetic wounds. The gelatin- silver oxide nanoparticles (Ag2O-NP) bio nanocomposite was prepared using chitosan and gelatin polymers incorporated with silver oxide nanoparticles through the freeze-drying method. The samples were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. Results showed that the Ag2O-NP nanoparticles increased porosity, decreased pore size, and improved elastic modulus. The Ag2O-NP wound dressing exhibited the most effective antibacterial properties against Staphylococcus aureus and Escherichia coli. Among the samples, the wound dressing containing silver oxide nanoparticles demonstrated superior physical and mechanical properties, with 48% porosity, a tensile strength of 3.2 MPa, and an elastic modulus of 51.7 MPa. The fabricated wound dressings had a volume ratio of empty space to total volume ranging from 40% to 60%. In parallel, considering the complications of diabetes and its impact on the vascular system, another aspect of the research focused on developing a per2mediated wound dressing capable of releasing nitric oxide gas to regenerate damaged vessels and accelerate diabetic wound healing. Chitosan, a biocompatible and biodegradable polymer, was selected as the substrate for the wound dressing, and beta-glycerophosphate (GPβ), tripolyphosphate (TPP), and per2mediated alginate (AL) were used as crosslinkers. The chitosan-alginate (CS-AL) wound dressing exhibited optimal characteristics in terms of hole count and uniformity in the scanning electron microscope test. It also demonstrated superior water absorption (3854%) and minimal air permeability. Furthermore, the CS-AL sample exhibited an 80% degradation rate after 14 days, indicating its suitability as a wound dressing. The wound dressing was loaded with S-nitrosoglutathione (GSNO) powder, and the successful release of nitric oxide gas was confirmed through the grease test, showing a peak at a wavelength of 540 nm. Subsequent investigations revealed that the treatment of human umbilical vein endothelial cells (HUVECs) with high glucose led to a decrease in the expression of PER2 and SIRT1, while the expression of PER2 increased, which may subsequently enhance the expression of SIRT1 and promote cell proliferation activity. However, upon treatment of the cells with the modified materials, an increase in the expression of PER2 and SIRT1 was observed, resulting in a partial restoration of cell proliferative activity. This comprehensive study successfully developed per2-mediated bio-nanocomposite wound dressings with improved physical, mechanical, chemical, and antibacterial properties. The incorporation of silver oxide nanoparticles enhanced the antimicrobial activity, while the released nitric oxide gas from the dressing demonstrated the ability to mitigate vascular endothelial cell damage induced by high glucose levels. These advancements show promising potential for facilitating the healing process of diabetic wounds by addressing complications associated with diabetes and enhancing overall wound healing.
Topics: Gelatin; Wound Healing; Nitric Oxide; Bandages; Silver Compounds; Humans; Escherichia coli; Anti-Bacterial Agents; Staphylococcus aureus; Chitosan; Metal Nanoparticles; Porosity; Diabetic Foot; Nanoparticles; Oxides
PubMed: 38885218
DOI: 10.1371/journal.pone.0298124 -
Sexual Medicine Jun 2024The endothelial glycocalyx is an important barrier that protects the structure and function of endothelial cells. Androgen deficiency is a common factor that causes...
BACKGROUND
The endothelial glycocalyx is an important barrier that protects the structure and function of endothelial cells. Androgen deficiency is a common factor that causes structural and functional impairment of endothelial cells.
AIM
To investigate changes in the endothelial glycocalyx in the penile corpus cavernosum of the rat with low androgen status and its relationship with erection function.
METHODS
Eighteen 10-week-old Sprague-Dawley male rats were randomly divided into 3 groups (n = 6 each): sham operation, castration, and castration + testosterone replacement. The maximum intracavernosal pressure/mean arterial pressure of the penis was measured after modeling for 4 weeks. The expression levels of endothelial nitric oxide synthase (eNOS), phospho-eNOS, syndecan 1, heparanase, and nitric oxide in penile cavernous tissue and the serum levels of heparan sulfate, hyaluronic acid, tumor necrosis factor α, and interleukin 6 were determined. Transmission electron microscopy was used to observe the ultrastructure of the endothelial glycocalyx in penile tissue.
OUTCOMES
The thickness of the endothelial glycocalyx in the penile corpus cavernosum of castrated rats was significantly lower than that of the control group.
RESULTS
In the castrated rats, the endothelial glycocalyx thickness, syndecan 1 level, ratio of phospho-eNOS to eNOS, nitric oxide level, and maximum intracavernosal pressure/mean arterial pressure (3 V, 5 V) were significantly lower than those in the sham group ( < .05). The expression of heparanase and the serum levels of tumor necrosis factor α and interleukin 6 were significantly higher in the castrated group than in the sham group ( < .05).
CLINICAL TRANSLATION
Upregulating the expression of the endothelial glycocalyx in the penile corpus cavernosum may be a new method for treating erectile dysfunction caused by low androgen levels.
STRENGTHS AND LIMITATIONS
This study confirms that low androgen status promotes the breakdown of the endothelial glycocalyx. However, further research is needed to determine whether androgens are related to the synthesis of the endothelial glycocalyx.
CONCLUSION
Low androgen status may suppress the level of nitric oxide in the cavernous tissue of the penis via impairment of the endothelial glycocalyx, resulting in inhibited erection function in rats.
PubMed: 38883807
DOI: 10.1093/sexmed/qfae039 -
Research Square Jun 2024The synthesis of water-soluble nanoparticles is a well-developed field for ferrite-based nanoparticles with the majority consisting of iron oxide or mixed metal iron...
The synthesis of water-soluble nanoparticles is a well-developed field for ferrite-based nanoparticles with the majority consisting of iron oxide or mixed metal iron oxide nanoparticles. However, the synthesis of non-agglomerated non-ferrite metal/metal oxide NPs is not as well established. The synthesis and characterization of uniform 20 nm, biologically compatible cobalt oxide (CoO) nanoparticles (NPs) is described. These nanoparticles have two principle components: 1) a CoO core of suitable size to contain enough cobalt atoms to be visualized by X-ray fluorescence microscopy (XFM) and 2) a robust coating that inhibits NP aggregation as well as renders them water-soluble and biocompatible (i.e. stealth coatings). Stable cobalt oxide NPs are obtained with octadecyl amine coatings as reported by Bhattacharjee. Two strategies for solubilizing these NPs in water were investigated with varying degrees of success. Exchanging the octadecyl amine coating for a nitrodopamine anchored PEG coating yielded the desired water-soluble NPs but in very low yield. Alternately, leaving the octadecyl amine coating on the NP and interdigitating this with a maleic anhydride-vinyl copolymer with different hydrophobic sidechains followed by opening the maleic anhydride ring with amine substituted PEG polymers (the water solubilizing component), yielded the desired water soluble NPS were obtained in good yield. Characterization data for the nanoparticles and the components of the coatings required for bioorthogonal reactions to ligate them with biotargeting agents are also described.
PubMed: 38883752
DOI: 10.21203/rs.3.rs-4312367/v1 -
Research Square Jun 2024Proteomic profiling of Alzheimer's disease (AD) brains has identified numerous understudied proteins, including midkine (MDK), that are highly upregulated and correlated...
Proteomic profiling of Alzheimer's disease (AD) brains has identified numerous understudied proteins, including midkine (MDK), that are highly upregulated and correlated with Aβ since the early disease stage, but their roles in disease progression are not fully understood. Here we present that MDK attenuates Aβ assembly and influences amyloid formation in the 5xFAD amyloidosis mouse model. MDK protein mitigates fibril formation of both Aβ40 and Aβ42 peptides in Thioflavin T fluorescence assay, circular dichroism, negative stain electron microscopy, and NMR analysis. Knockout of gene in 5xFAD increases amyloid formation and microglial activation. Further comprehensive mass spectrometry-based profiling of whole proteome and aggregated proteome in these mouse models indicates significant accumulation of Aβ and Aβ-correlated proteins, along with microglial components. Thus, our structural and mouse model studies reveal a protective role of MDK in counteracting amyloid pathology in Alzheimer's disease.
PubMed: 38883748
DOI: 10.21203/rs.3.rs-4361125/v1 -
Journal of Thoracic Disease May 2024Chronic obstructive pulmonary disease (COPD) is significantly influenced by oxidative stress. Recent studies have elucidated the anti-oxidative stress properties of...
BACKGROUND
Chronic obstructive pulmonary disease (COPD) is significantly influenced by oxidative stress. Recent studies have elucidated the anti-oxidative stress properties of peroxisome proliferator-activated receptors γ (PPARγ), augmenting its known anti-inflammatory effects. The exact influence of PPARγ on oxidative stress in COPD remains elusive. This study aimed to investigate the potential mechanism by which PPARγ counteracts the oxidative stress instigated by cigarette smoke in macrophages.
METHODS
Macrophages were cultured and exposed to 1% cigarette smoke extract (CSE), 1 µg/mL erythromycin (EM), and 10 µmol/mL GW9662 (a PPARγ antagonist). Reactive oxygen species (ROS) in macrophages was identified using fluorescent microscopy. PPARγ expression was ascertained through reverse transcription-polymerase chain reaction (RT-PCR) and Western blot techniques. The superoxide dismutase (SOD) in macrophage supernatant was measured by enzyme linked immunosorbent assay (ELISA), as was malondialdehyde (MDA).
RESULTS
Our results shown that cigarette smoke stimulated macrophages to increase ROS release, decrease the expression of PPARγ, increase the expression of MDA and decrease the expression of SOD. After PPARγ inhibitor acted on macrophages stimulated by cigarette smoke, the expression of MDA was inhibited and the content of SOD increased. When EM was used to treat macrophages stimulated by cigarette smoke, the expression of ROS decreased, the expression of PPARγ increased, the expression of MDA decreased and the expression of SOD increased.
CONCLUSIONS
This study suggests that PPARγ plays an anti-oxidative role by inhibiting the expression of MDA and promoting the expression of SOD. Cigarette smoke induces oxidative stress by inhibiting PPARγ pathway. EM inhibits oxidative stress by activating PPARγ pathway.
PubMed: 38883674
DOI: 10.21037/jtd-23-1647