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BioRxiv : the Preprint Server For... Jun 2024Vertebrate radial glia progenitors (RGPs), the principal neural stem cells, balance self-renewal and differentiation through asymmetric cell division (ACD), during which...
Vertebrate radial glia progenitors (RGPs), the principal neural stem cells, balance self-renewal and differentiation through asymmetric cell division (ACD), during which unequal inheritance of centrosomes is observed. Mechanistically, how centrosome asymmetry leads to distinct daughter cell fate remains largely unknown. Here we find that the centrosome protein Pericentriolar Material 1 (Pcm1), asymmetrically distributed at the centrosomes, regulates polarized endosome dynamics and RGP fate. time-lapse imaging and nanoscale-resolution expansion microscopy of zebrafish embryonic RGPs detect Pcm1 on Notch ligand-containing endosomes, in a complex with the polarity regulator Par-3 and dynein motor. Loss of disrupts endosome dynamics, with clonal analysis uncovering increased neuronal production at the expense of progenitors. Pcm1 facilitates an exchange of Rab5b (early) for Rab11a (recycling) endosome markers and promotes the formation of Par-3 and dynein macromolecular complexes on recycling endosomes. Finally, in human-induced pluripotent stem cell-derived brain organoids, PCM1 shows asymmetry and co-localization with PARD3 and RAB11A in mitotic neural progenitors. Our data reveal a new mechanism by which centrosome asymmetry is conveyed by Pcm1 to polarize endosome dynamics and Notch signaling in regulating ACD and progenitor fate.
PubMed: 38948739
DOI: 10.1101/2024.06.17.599416 -
BioRxiv : the Preprint Server For... Jun 2024Cell corpses must be cleared in an efficient manner to maintain tissue homeostasis and regulate immune responses. Ubiquitin-like Atg8/LC3 family proteins promote the...
Cell corpses must be cleared in an efficient manner to maintain tissue homeostasis and regulate immune responses. Ubiquitin-like Atg8/LC3 family proteins promote the degradation of membranes and internal cargo during both macroautophagy and corpse clearance, raising the question how macroautophagy contributes to corpse clearance. Studying the clearance of non-apoptotic dying polar bodies in embryos, we show that the LC3 ortholog LGG-2 is enriched in the polar body phagolysosome independent of membrane association or autophagosome formation. We demonstrate that ATG-16.1 and ATG-16.2, which promote membrane association of lipidated Atg8/LC3 proteins, redundantly promote polar body membrane breakdown in phagolysosomes independent of their role in macroautophagy. We also show that the lipid scramblase ATG-9 is needed for autophagosome formation in early embryos but is dispensable for timely polar body membrane breakdown or protein cargo degradation. These findings demonstrate that macroautophagy is not required to promote polar body degradation, in contrast to recent findings with apoptotic corpse clearance in embryos. Determining how membrane association of Atg8/LC3 promotes the breakdown of different types of cell corpses in distinct cell types or metabolic states is likely to give insights into the mechanisms of immunoregulation during normal development, physiology, and disease.
PubMed: 38948720
DOI: 10.1101/2024.06.19.599770 -
ImmunoTargets and Therapy 2024Medulloblastoma (MB) is the most prevalent paediatric brain tumour. Despite improvements in patient survival with current treatment strategies, the quality of life of...
PURPOSE
Medulloblastoma (MB) is the most prevalent paediatric brain tumour. Despite improvements in patient survival with current treatment strategies, the quality of life of these patients remains poor owing to the sequelae and relapse risk. An alternative, or, in addition to the current standard treatment, could be considered immunotherapy, such as Natural Killer cells (NK). NK cells are cytotoxic innate lymphoid cells that play a major role in cancer immunosurveillance. To date, the mechanism of cytotoxicity of NK cells, especially regarding the steps of adhesion, conjugation, cytotoxic granule polarisation in the cell contact area, perforin and granzyme release in two and three dimensions, and therapeutic efficacy in vivo have not been precisely described.
MATERIALS AND METHODS
Each step of NK cytotoxicity against the three MB cell lines was explored using confocal microscopy for conjugation, Elispot for degranulation, flow cytometry, and luminescence assays for target cell necrosis and lysis and mediators released by cytokine array, and then confirmed in a 3D spheroid model. Medulloblastoma-xenografted mice were treated with NK cells. Their persistence was evaluated by flow cytometry, and their efficacy in tumour growth and survival was determined. In addition, their effects on the tumour transcriptome were evaluated.
RESULTS
NK cells showed variable affinities for conjugation with MB target cells depending on their subgroup and cytokine activation. Chemokines secreted during NK and MB cell co-culture are mainly associated with angiogenesis and immune cell recruitment. NK cell cytotoxicity induces MB cell death in both 2D and 3D co-culture models. NK cells initiated an inflammatory response in a human MB murine model by modulating the MB cell transcriptome.
CONCLUSION
Our study confirmed that NK cells possess both in vitro and in vivo cytotoxic activity against MB cells and are of interest for the development of immunotherapy.
PubMed: 38948503
DOI: 10.2147/ITT.S458278 -
Sichuan Da Xue Xue Bao. Yi Xue Ban =... May 2024Intracerebral hemorrhage (ICH), the second most common type of stroke, can cause long-lasting disability in the afflicted patients. The study was conducted to examine...
[Relationship Between the Migration of Endogenous Neural Stem Cells and the Pattern of Change in Immune Cell Phenotypes in the Microenvironment After Intracerebral Hemorrhage in Rats].
OBJECTIVE
Intracerebral hemorrhage (ICH), the second most common type of stroke, can cause long-lasting disability in the afflicted patients. The study was conducted to examine the patterns of change in endogenous neural stem cells (eNSCs) and in the regenerative microenvironment after ICH, to observe the relationship between the migration of eNSCs and the pattern of change in the polarization state of immune cells in the microenvironment, and provide a research basis for research on clinical nerve repair.
METHODS
The collagenase injection method was used for modeling. The ICH model was induced in adult female Sprague-Dawley (SD) rats by injecting type VII collagenase (2 U) into the brain tissue of rats. All the experimental rats weighed 280-300 g. In order to simulate the ICU at different time points, including the acute phase (within 1 week), subacute phase (1-3 weeks), and the chronic phase (over 3 weeks), brain tissues were harvested at 3 day post injection (3 DPI), 10 DPI, 20 DPI, and 30 DPI to evaluate the modeling effect. Immunofluorescence staining of the brain tissue sections was performed with DCX antibody to observe the pattern of change in the migration of eNSCs in the brain tissue at different time points. Immunofluorescence staining of brain tissue sections was performed with CD206 antibody and CD86 antibody for respective observation of the pattern of change in pro-inflammatory (M1-type) and anti-inflammatory (M2-type) immune cells in the regenerative microenvironment of the brain tissue after ICM.
RESULTS
Spontaneous ICH was successfully induced by injecting type Ⅶ collagenase into the brain tissue of SD rats. The volume of the hematoma formed started to gradually increase at 3 DPI and reached its maximum at 10 DPI. After that, the hematoma was gradually absorbed and was completely absorbed by 30 DPI. Analysis of the pattern of changes in eNSCs in the brain tissue showed that a small number of eNSCs were activated at 3 DPI, but very soon their number started to decrease. By 10 DPI, eNSCs gradually began to increase. A large number of eNSCs migrated to the hemorrhage site at 20 DPI. Then the number of eNSCs decreased significantly at 30 DPI (<0.01). Analysis of the immune microenvironment of the brain tissue showed that pro-inflammatory (M1 type) immune cells increased significantly at 10 and 20 DPI (<0.01) and decreased at 30 DPI. Anti-inflammatory (M2 type) immune cells began to increase gradually at 3 DPI, decreased significantly at 20 DPI (<0.05), and then showed an increase at 30 DPI.
CONCLUSION
After ICH in rats, eNSCs migrating toward the site of ICH first increase and then decrease. The immune microenvironment demonstrates a pattern of change in which inflammation is suppressed at first, then promoted, and finally suppressed again. Inflammation may have a stimulatory effect on the migration of eNSCs, but excessive inflammatory activation has an inhibitory effect on the differentiation and further activation of eNSCs. After ICH, the early stage of repair and protection (10 d) and the subacute phase (20 d) may provide the best opportunities for intervention.
Topics: Animals; Rats, Sprague-Dawley; Cerebral Hemorrhage; Rats; Female; Doublecortin Protein; Neural Stem Cells; Cell Movement; Disease Models, Animal; Phenotype; Brain; Macrophages
PubMed: 38948290
DOI: 10.12182/20240560402 -
MethodsX Jun 2024Chromatography combined with mass spectrometry is a gold standard technique for steroid measurement, however the type of sample preparation, the dynamic range and...
Chromatography combined with mass spectrometry is a gold standard technique for steroid measurement, however the type of sample preparation, the dynamic range and reliability of the calibration curve, the chromatographic separation and mass spectrometry settings ultimately determine the success of the method. The steroid biosynthetic pathway is conserved in higher mammals and literature demonstrates that the concentration ranges of different steroid groups are relatively comparable across species. We sought to develop a robust and reliable multi steroid targeted analysis method for blood that would have wide application across higher mammals. The method was developed following bioanalytical method validation guidelines to standards typically applied to human clinical studies, including isotopically labelled internal standards where at all possible. Here we describe the practical approach to a 96-well supported liquid extraction (SLE) method of extraction from plasma (200 µL) using an Extrahera liquid handling robot (Biotage, Sweden), including quality control samples, followed by a comprehensive separation and targeted LC-MS/MS analysis of 18 steroids in plasma (pregnenolone, progesterone, 17α-hydroxyprogesterone, 11-deoxycorticosterone, corticosterone, 11-dehydrocorticosterone, aldosterone, 11-deoxycortisol, 21-deoxycortisol, cortisol, cortisone, androstenedione, testosterone, 5α-dihydrotestosterone, dehydroepiandrosterone, estrone, 17β-estradiol and estriol). •SLE in a 96-well format of up to 74 biological plasma samples, enriched with multiple isotopically labelled internal standards, a 12-point aqueous calibration curve, and 6 serum quality controls, designed to monitor long-term performance of the method•Chromatographic separation of multiple steroids along the gradient, with ammonium fluoride mobile phase additive to improve sensitivity, followed by electrospray ionisation and constant polarity switching•Aqueous calibration standards that cover physiologically relevant ranges - high nanomolar glucocorticoids, low nanomolar androgens and picomolar ranges for estrogens and steroid intermediates.
PubMed: 38948242
DOI: 10.1016/j.mex.2024.102728 -
Biodiversity Data Journal 2024The investigation of Agaricales diversity in the Antarctica is limited, with only seven genera reported for the region. stands out as the genus with the highest species...
BACKGROUND
The investigation of Agaricales diversity in the Antarctica is limited, with only seven genera reported for the region. stands out as the genus with the highest species diversity, including 12 species in Antarctica. This research reports the presence of in the region, providing the first complete morphological description for the specimen developing in Antarctica. Sampling was conducted during the Austral summer of 2022/2023 as part of the XLI Brazilian Antarctic Operation in Point Smellie, Byers Peninsula, Livingston Island, South Shetland Archipelago, Antarctica. Phylogenetic relationships reconstructed by Maximum Likelihood demonstrate that forms a monophyletic clade with over 60% bootstrap support in most branches. The isolate in this study was found to be internal to the main cluster. Evolutionary reconstructions using the Maximum Likelihood method indicate that the branches correspond to the Antarctic isolate being an internal clade within the group. Recording fungal populations in polar regions offers information about their adaptation and survival in inhospitable environments. Understanding the species' distribution in Antarctica encourages future investigations into its ecology and interactions with other organisms. Here, data are presented to establish an initial foundation for monitoring the population in Antarctica and assessing the potential impacts of climate change on its development and survival in the forthcoming years.
NEW INFORMATION
We report the third occurrence of (Batsch) Kühner in Antarctica and provide, for the first time, a comprehensive morphological description of an individual of the species for the Antarctic continent, accompanied by phylogenetic analyses and comprehensive discussions regarding its diversity and global distribution.
PubMed: 38948134
DOI: 10.3897/BDJ.12.e125727 -
Theranostics 2024The repair of osteoporotic bone defects remains challenging due to excessive reactive oxygen species (ROS), persistent inflammation, and an imbalance between...
The repair of osteoporotic bone defects remains challenging due to excessive reactive oxygen species (ROS), persistent inflammation, and an imbalance between osteogenesis and osteoclastogenesis. Here, an injectable H-releasing hydrogel (magnesium@polyethylene glycol-poly(lactic-co-glycolic acid), Mg@PEG-PLGA) was developed to remodel the challenging bone environment and accelerate the repair of osteoporotic bone defects. This Mg@PEG-PLGA gel shows excellent injectability, shape adaptability, and phase-transition ability, can fill irregular bone defect areas via minimally invasive injection, and can transform into a porous scaffold to provide mechanical support. With the appropriate release of H and magnesium ions, the 2Mg@PEG-PLGA gel (loaded with 2 mg of Mg) displayed significant immunomodulatory effects through reducing intracellular ROS, guiding macrophage polarization toward the M2 phenotype, and inhibiting the IκB/NF-κB signaling pathway. Moreover, experiments showed that the 2Mg@PEG-PLGA gel inhibited osteoclastogenesis while promoting osteogenesis. Most notably, in animal experiments, the 2Mg@PEG-PLGA gel significantly promoted the repair of osteoporotic bone defects by scavenging ROS and inhibiting inflammation and osteoclastogenesis. Overall, our study provides critical insight into the design and development of H-releasing magnesium-based hydrogels as potential implants for repairing osteoporotic bone defects.
Topics: Animals; Magnesium; Reactive Oxygen Species; Mice; Polyethylene Glycols; Hydrogels; Osteoporosis; Osteogenesis; Hydrogen; RAW 264.7 Cells; Bone Regeneration; Immunomodulation; Tissue Scaffolds; Macrophages; Polyesters
PubMed: 38948054
DOI: 10.7150/thno.97412 -
Chemistry of Materials : a Publication... Jun 2024Phase-pure polycrystalline BaRuMnO was prepared and determined to adopt the noncentrosymmetric polar crystal structure (space group 2) based on results of second...
Phase-pure polycrystalline BaRuMnO was prepared and determined to adopt the noncentrosymmetric polar crystal structure (space group 2) based on results of second harmonic generation, convergent beam electron diffraction, and Rietveld refinements using powder neutron diffraction data. The crystal structure features zigzag chains of corner-shared trimers, which contain three distorted face-sharing octahedra. The three metal sites in the trimers are occupied by disordered Ru/Mn with three different ratios: Ru1:Mn1 = 0.202(8):0.798(8), Ru2:Mn2 = 0.27(1):0.73(1), and Ru3:Mn3 = 0.40(1):0.60(1), successfully lowering the symmetry and inducing the polar crystal structure from the centrosymmetric parent compounds BaTO (T = Mn, Ru; space group ). The valence state of Ru/Mn is confirmed to be +4 according to X-ray absorption near-edge spectroscopy. BaRuMnO is a narrow bandgap (∼0.6 eV) semiconductor exhibiting spin-glass behavior with strong magnetic frustration and antiferromagnetic interactions.
PubMed: 38947978
DOI: 10.1021/acs.chemmater.4c00586 -
Cureus May 2024Leprosy is a chronic infection of the skin, eyes, and peripheral nerves due to the slow-growing, acid-fast bacillus . Devastating complications include Charcot...
Leprosy is a chronic infection of the skin, eyes, and peripheral nerves due to the slow-growing, acid-fast bacillus . Devastating complications include Charcot neuroarthropathy and insensate hands and feet. We present the case of an 81-year-old female with rheumatoid arthritis and 50 years of polar lepromatous leprosy who suffered from bilateral collapsed arches, flat feet, and bone deformities of Charcot feet.
PubMed: 38947585
DOI: 10.7759/cureus.61362 -
IScience Jun 2024Drug efflux transporters are a major determinant of drug efficacy and toxicity. A canonical example is P-glycoprotein (P-gp), an efflux transporter that controls the...
Drug efflux transporters are a major determinant of drug efficacy and toxicity. A canonical example is P-glycoprotein (P-gp), an efflux transporter that controls the intestinal absorption of diverse compounds. Despite a rich literature on the dietary and pharmaceutical compounds that impact P-gp activity, its sensitivity to gut microbial metabolites remains an open question. Surprisingly, we found that the cardiac drug-metabolizing gut Actinobacterium increases drug absorption in mice. Experiments in cell culture revealed that produces a soluble factor that post-translationally inhibits P-gp ATPase efflux activity. P-gp inhibition is conserved in the family but absent in other Actinobacteria. Comparative genomics identified genes associated with P-gp inhibition. Finally, activity-guided biochemical fractionation coupled to metabolomics implicated a group of small polar metabolites with P-gp inhibitory activity. These results highlight the importance of considering the broader relevance of the gut microbiome for drug disposition beyond first-pass metabolism.
PubMed: 38947502
DOI: 10.1016/j.isci.2024.110122