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Advanced Science (Weinheim,... Nov 2023Advancing the technologies for cellular reprogramming with high efficiency has significant impact on regenerative therapy, disease modeling, and drug discovery....
Advancing the technologies for cellular reprogramming with high efficiency has significant impact on regenerative therapy, disease modeling, and drug discovery. Biophysical cues can tune the cell fate, yet the precise role of external physical forces during reprogramming remains elusive. Here the authors show that temporal cyclic-stretching of fibroblasts significantly enhances the efficiency of induced pluripotent stem cell (iPSC) production. Generated iPSCs are proven to express pluripotency markers and exhibit in vivo functionality. Bulk RNA-sequencing reveales that cyclic-stretching enhances biological characteristics required for pluripotency acquisition, including increased cell division and mesenchymal-epithelial transition. Of note, cyclic-stretching activates key mechanosensitive molecules (integrins, perinuclear actins, nesprin-2, and YAP), across the cytoskeletal-to-nuclear space. Furthermore, stretch-mediated cytoskeletal-nuclear mechano-coupling leads to altered epigenetic modifications, mainly downregulation in H3K9 methylation, and its global gene occupancy change, as revealed by genome-wide ChIP-sequencing and pharmacological inhibition tests. Single cell RNA-sequencing further identifies subcluster of mechano-responsive iPSCs and key epigenetic modifier in stretched cells. Collectively, cyclic-stretching activates iPSC reprogramming through mechanotransduction process and epigenetic changes accompanied by altered occupancy of mechanosensitive genes. This study highlights the strong link between external physical forces with subsequent mechanotransduction process and the epigenetic changes with expression of related genes in cellular reprogramming, holding substantial implications in the field of cell biology, tissue engineering, and regenerative medicine.
Topics: Mechanotransduction, Cellular; Cellular Reprogramming; Induced Pluripotent Stem Cells; Epigenesis, Genetic; RNA
PubMed: 37727069
DOI: 10.1002/advs.202303395 -
Diseases (Basel, Switzerland) Jun 2023Oxymetholone is one of the anabolic steroids that has widely been used among teenagers and athletes to increase their muscle bulk. It has undesirable effects on male...
Oxymetholone is one of the anabolic steroids that has widely been used among teenagers and athletes to increase their muscle bulk. It has undesirable effects on male health and fertility. In this study, the therapeutic effects of platelet-rich plasma (PRP) on oxymetholone-induced testicular toxicity were investigated in adult albino rats. During the experiments, 49 adult male albino rats were divided into 4 main groups: Group 0 (donor group) included 10 rats for the donation of PRP, Group I (control group) included 15 rats, Group II included 8 rats that received 10 mg/kg of oxymetholone orally, once daily, for 30 days, and Group III included 16 rats and was subdivided into 2 subgroups (IIIa and IIIb) that received oxymetholone the same as group II and then received PRP once and twice, respectively. Testicular tissues of all examined rats were obtained for processing and histological examination and sperm smears were stained and examined for sperm morphology. Oxymetholone-treated rats revealed wide spaces in between the tubules, vacuolated cytoplasm, and dark pyknotic nuclei of most cells, as well as deposition of homogenous acidophilic material between the tubules. Electron microscopic examination showed vacuolated cytoplasm of most cells, swollen mitochondria, and perinuclear dilatation. Concerning subgroup IIIa (PRP once), there was a partial improvement in the form of decreased vacuolations and regeneration of spermatogenic cells, as well as a reasonable improvement in sperm morphology. Regarding subgroup IIIb (PRP twice), histological sections revealed restoration of the normal testicular structure to a great extent, regeneration of the spermatogenic cells, and most sperms had normal morphology. Thus, it is recommended to use PRP to minimize structural changes in the testis of adult albino rats caused by oxymetholone.
PubMed: 37366872
DOI: 10.3390/diseases11020084 -
Cell Dec 2016In this issue of Cell, Skau et al. show that the formin FMN2 organizes a perinuclear actin cytoskeleton that protects the nucleus and its genomic content of migrating...
In this issue of Cell, Skau et al. show that the formin FMN2 organizes a perinuclear actin cytoskeleton that protects the nucleus and its genomic content of migrating cells squeezing through small spaces.
Topics: Actin Cytoskeleton; Actins; Cell Nucleus; Humans; Microfilament Proteins
PubMed: 27912053
DOI: 10.1016/j.cell.2016.11.024 -
BioRxiv : the Preprint Server For... Jul 2023TorsinA is an atypical ATPase that lacks intrinsic activity unless it is bound to its activators lamina-associated polypeptide 1 (LAP1) in the perinuclear space or...
TorsinA is an atypical ATPase that lacks intrinsic activity unless it is bound to its activators lamina-associated polypeptide 1 (LAP1) in the perinuclear space or luminal domain-like LAP1 (LULL1) throughout the endoplasmic reticulum. However, the interaction of torsinA with LAP1 and LULL1 has not yet been shown to modulate a defined physiological process in mammals . We previously demonstrated that depletion of torsinA from mouse hepatocytes leads to reduced liver triglyceride secretion and marked steatosis, whereas depletion of LAP1 had more modest similar effects. We now show that depletion of LULL1 alone does not significantly decrease liver triglyceride secretion or cause steatosis. However, simultaneous depletion of both LAP1 and LULL1 from hepatocytes leads to defective triglyceride secretion and marked steatosis similar to that observed with depletion of torsinA. Our results demonstrate that torsinA and its activators dynamically regulate a physiological process in mammals .
PubMed: 37547008
DOI: 10.1101/2023.06.21.545957 -
Molecular Biology of the Cell May 2022How nuclear pore complexes (NPCs) assemble in the intact nuclear envelope (NE) is only rudimentarily understood. Nucleoporins (Nups) accumulate at the inner nuclear...
How nuclear pore complexes (NPCs) assemble in the intact nuclear envelope (NE) is only rudimentarily understood. Nucleoporins (Nups) accumulate at the inner nuclear membrane (INM) and deform this membrane toward the outer nuclear membrane (ONM), and eventually INM and ONM fuse by an unclear mechanism. In budding yeast, the integral membrane protein Brl1 that transiently associates with NPC assembly intermediates is involved in INM/ONM fusion during NPC assembly but leaving the molecular mechanism open. AlphaFold predictions indicate that Brl1-like proteins carry as common motifs an α-helix with amphipathic features (AαH) and a disulfide-stabilized, anti-parallel helix bundle (DAH) in the perinuclear space. Mutants with defective AαH (, ) impair the essential function of . Overexpression of promotes the formation of INM and ONM enclosed petal-like structures that carry Nups at their base, suggesting that they are derived from an NPC assembly attempt with failed INM/ONM fusion. Accordingly, expression triggers mislocalization of Nup159 and Nup42 and to a lesser extent Nsp1, which localize on the cytoplasmic face of the NPC. The DAH also contributes to the function of Brl1, and AαH has functions independent of DAH. We propose that AαH and DAH in Brl1 promote INM/ONM fusion during NPC assembly.
Topics: Membrane Proteins; Nuclear Envelope; Nuclear Pore; Nuclear Pore Complex Proteins; Protein Conformation, alpha-Helical; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins
PubMed: 35293775
DOI: 10.1091/mbc.E21-12-0616 -
Open Biology Nov 2021The integral membrane protein Apq12 is an important nuclear envelope (NE)/endoplasmic reticulum (ER) modulator that cooperates with the nuclear pore complex (NPC)...
The integral membrane protein Apq12 is an important nuclear envelope (NE)/endoplasmic reticulum (ER) modulator that cooperates with the nuclear pore complex (NPC) biogenesis factors Brl1 and Brr6. How Apq12 executes these functions is unknown. Here, we identified a short amphipathic α-helix (AH) in Apq12 that links the two transmembrane domains in the perinuclear space and has liposome-binding properties. Cells expressing an () version in which AH is disrupted show NPC biogenesis and NE integrity defects, without impacting Apq12-ah topology or NE/ER localization. Overexpression of but not triggers striking over-proliferation of the outer nuclear membrane (ONM)/ER and promotes accumulation of phosphatidic acid (PA) at the NE. Apq12 and Apq12-ah both associate with NPC biogenesis intermediates and removal of AH increases both Brl1 levels and the interaction between Brl1 and Brr6. We conclude that the short amphipathic α-helix of Apq12 regulates the function of Brl1 and Brr6 and promotes PA accumulation at the NE possibly during NPC biogenesis.
Topics: Membrane Proteins; Mutation; Nuclear Envelope; Nuclear Pore; Phosphatidic Acids; Protein Conformation, alpha-Helical; Protein Domains; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins
PubMed: 34814743
DOI: 10.1098/rsob.210250 -
Frontiers in Molecular Biosciences 2017Torsins are essential, disease-relevant AAA+ (ATPases associated with various cellular activities) proteins residing in the endoplasmic reticulum and perinuclear space,...
Torsins are essential, disease-relevant AAA+ (ATPases associated with various cellular activities) proteins residing in the endoplasmic reticulum and perinuclear space, where they are implicated in a variety of cellular functions. Recently, new structural and functional details about Torsins have emerged that will have a profound influence on unraveling the precise mechanistic details of their yet-unknown mode of action in the cell. While Torsins are phylogenetically related to Clp/HSP100 proteins, they exhibit comparatively weak ATPase activities, which are tightly controlled by virtue of an active site complementation through accessory cofactors. This control mechanism is offset by a TorsinA mutation implicated in the severe movement disorder DYT1 dystonia, suggesting a critical role for the functional Torsin-cofactor interplay . Notably, TorsinA lacks aromatic pore loops that are both conserved and critical for the processive unfolding activity of Clp/HSP100 proteins. Based on these distinctive yet defining features, we discuss how the apparent dynamic nature of the Torsin-cofactor system can inform emerging models and hypotheses for Torsin complex formation and function. Specifically, we propose that the dynamic assembly and disassembly of the Torsin/cofactor system is a critical property that is required for Torsins' functional roles in nuclear trafficking and nuclear pore complex assembly or homeostasis that merit further exploration. Insights obtained from these future studies will be a valuable addition to our understanding of disease etiology of DYT1 dystonia.
PubMed: 28553638
DOI: 10.3389/fmolb.2017.00029 -
Archives of Razi Institute Oct 2021The soft and delicate tissue of the brain, which is the center of our coordination, is protected by its surrounding layers. The disruption of these layers results in...
The soft and delicate tissue of the brain, which is the center of our coordination, is protected by its surrounding layers. The disruption of these layers results in complicated situations and serious health problems. The brain has three protective layers of bone or skull tissue, the blood tissue layer, and finally the meningeal layer. The layer of blood tissue contains the blood vessels that are located between the skull and the meningeal membranes. If germs or foreign matter enter the fluid through the blood vessels under any circumstances and cause infection, the bones that protect the meninges will break and cause tissue damage. The present study aimed to assess the histological and immunohistochemical characteristics of the brain of rats that underwent induced acute purulent pneumococcal meningitis after antibiotic therapy with Ceftriaxone. A number of 20 white adult male Wistar rats were assigned to three groups. The first group (n=5) regarded as the control were injected with a saline solution into the subarachnoid space in an equivalent amount. The second and third groups of rats (n=5 and 10, respectively) were infected with acute purulent meningitis by the injection of 10 μl of Streptococcus pneumoniae (S. pneumonia) suspension into the subarachnoid space of the brain using a 23-G needle. The various areas of the brains of rats after meningitis induced by S. pneumoniae were examined after the treatment with Ceftriaxone. The S. pneumoniae culture was injected into the subarachnoid space in the area of the rhomboid fossa. Treatment started 18 h after the injection. On day 10, a repeated puncture was performed with the analysis of cerebrospinal fluid in order to confirm the absence of meningitis; thereafter, the animals were taken out of the experiment. No signs of meningitis were found on histological examination. Mild perivascular and pericellular focal edema were revealed with signs of overload of the lymphatic system in the brain and focal ischemic changes in neurons. The investigation of expression with caspase-3 revealed a positive reaction of individual neurons. A positive reaction with antibodies to NeuN and Doublecortin was detected in most neurons; moreover, Glial fibrillary acidic protein (GFAP)-positive astrocytes and their processes were visualized in all layers of the brain substance. The reaction with neuron-specific enolase (NSE), microtubule-associated protein 2 (MAP-2), CD 31, and CD 34 was negative. Typical structure and pictures pointed to an intact brain and purulent meningitis in the first and second groups. The microscopic image and the changes revealed during immunohistochemistry by dual corticosteroid antibodies and neuronal nuclear protein were characterized by predominantly cytoplasmic and perinuclear reactions, respectively. Some neurons are positive for caspase-3 and are related to changes in the characteristic of premature aging.
Topics: Animals; Male; Rats; Anti-Bacterial Agents; Brain; Ceftriaxone; Meningitis, Pneumococcal; Rats, Wistar
PubMed: 35096336
DOI: 10.22092/ari.2021.355885.1733 -
Journal of Virology Dec 2019The herpesvirus nuclear egress complex (NEC) is composed of two viral proteins. They play key roles in mediating the translocation of capsids from the nucleus to the...
The herpesvirus nuclear egress complex (NEC) is composed of two viral proteins. They play key roles in mediating the translocation of capsids from the nucleus to the cytoplasm by facilitating the budding of capsids into the perinuclear space (PNS). The NEC of alphaherpesvirus can induce the formation of virion-like vesicles from the nuclear membrane in the absence of other viral proteins. However, whether the NEC of gammaherpesvirus harbors the ability to do so in mammalian cells remains to be determined. In this study, we first constructed open reading frame 67 (ORF67)-null and ORF69-null mutants of murine gammaherpesvirus 68 (MHV-68) and demonstrated that both ORF67 and ORF69 play critical roles in nuclear egress and hence viral lytic replication. Biochemical and bioimaging analyses showed that ORF67 and ORF69 interacted with each other and were sufficient to induce the formation of virion-like vesicles from the nuclear membrane in mammalian cells. Thus, we designated ORF67 and ORF69 components of MHV-68 NEC. Furthermore, we identified amino acids critical for mediating the interaction between ORF67 and ORF69 through homology modeling and verified their function in nuclear egress, providing insights into the molecular basis of NEC formation in gammaherpesviruses. Increasing amounts of knowledge indicate that the nuclear egress complex (NEC) is critical for the nuclear egress of herpesvirus capsids, which can be viewed as a vesicle-mediated transport pathway through the nuclear membrane. In this study, we identified open reading frame 67 (ORF67) and ORF69 as components of the NEC in murine gammaherpesvirus 68 (MHV-68) and demonstrated that they efficiently induce virion-like vesicles from the nuclear membrane in mammalian cells. This is the first time that the NEC of a gammaherpesvirus has been found to demonstrate such an essential characteristic. In addition, we identified amino acids critical for mediating the interaction between ORF67 and ORF69 as well as nuclear egress. Notably, these amino acids are conserved in Kaposi's sarcoma-associated herpesvirus (KSHV) and Epstein-Barr virus (EBV), providing a structural basis to design antigammaherpesvirus drugs.
Topics: Active Transport, Cell Nucleus; Animals; Capsid; Cell Nucleus; Cytoplasm; DNA, Viral; Gammaherpesvirinae; HEK293 Cells; HeLa Cells; Herpesviridae; Herpesviridae Infections; Herpesvirus 4, Human; Herpesvirus 8, Human; Humans; Loss of Function Mutation; Mice; Nuclear Envelope; Open Reading Frames; Viral Envelope Proteins; Viral Proteins; Virion; Virus Replication
PubMed: 31554685
DOI: 10.1128/JVI.01422-19 -
Biochimica Et Biophysica Acta.... Jan 2022Membraneless organelles have emerged during the evolution of eukaryotic cells as intracellular domains in which multiple proteins organize into complex structures to...
Membraneless organelles have emerged during the evolution of eukaryotic cells as intracellular domains in which multiple proteins organize into complex structures to perform specialized functions without the need of a lipid bilayer compartment. Here we describe the perinuclear space of eukaryotic cells as a highly organized network of cytoskeletal filaments that facilitates assembly of biomolecular condensates. Using bioinformatic analyses, we show that the perinuclear proteome is enriched in intrinsic disorder with several proteins predicted to undergo liquid-liquid phase separation. We also analyze immunofluorescence and transmission electron microscopy images showing the association between the nucleus and other organelles, such as mitochondria and lysosomes, or the labeling of specific proteins within the perinuclear region of cells. Altogether our data support the existence of a perinuclear dense sub-micron region formed by a well-organized three-dimensional network of structural and signaling proteins, including several proteins containing intrinsically disordered regions with phase behavior. This network of filamentous cytoskeletal proteins extends a few micrometers from the nucleus, contributes to local crowding, and organizes the movement of molecular complexes within the perinuclear space. Our findings take a key step towards understanding how membraneless regions within eukaryotic cells can serve as hubs for biomolecular condensates assembly, in particular the perinuclear space. Finally, evaluation of the disease context of the perinuclear proteins revealed that alterations in their expression can lead to several pathological conditions, and neurological disorders and cancer are among the most frequent.
Topics: Actin Cytoskeleton; Animals; Cells, Cultured; Chick Embryo; Intrinsically Disordered Proteins; Lysosomes; Microscopy, Electron, Transmission; Mitochondria; Nuclear Envelope; Proteome; Zebrafish
PubMed: 34655689
DOI: 10.1016/j.bbamcr.2021.119161