Faculty Bibliography
Searched for:
school:SOM
Department/Unit:Cell Biology
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14100
Acta crystallographica. Section C, Structural chemistry. 2024:80(Pt 6):179-189.DOI: 10.1107/S2053229624004078
Applying 3D ED/MicroED workflows toward the next frontiers
We report on the latest advancements in Microcrystal Electron Diffraction (3D ED/MicroED), as discussed during a symposium at the National Center for CryoEM Access and Training housed at the New York Structural Biology Center. This snapshot describes cutting-edge developments in various facets of the field and identifies potential avenues for continued progress. Key sections discuss instrumentation access, research applications for small molecules and biomacromolecules, data collection hardware and software, data reduction software, and finally reporting and validation. 3D ED/MicroED is still early in its wide adoption by the structural science community with ample opportunities for expansion, growth, and innovation.
PMCID:11150879
PMID: 38712546
ISSN: 2053-2296
CID: 5664772
The Role of Hyaluronan/Receptor for Hyaluronan-Mediated Motility Interactions in the Modulation of Macrophage Polarization and Cartilage Repair
Hyaluronan (HA), a negatively charged linear glycosaminoglycan, is a key macromolecular component of the articular cartilage extracellular matrix. The differential effects of HA are determined by a spatially/temporally regulated display of HA receptors, such as CD44 and receptor for hyaluronan-mediated motility (RHAMM). HA signaling through CD44 with RHAMM has been shown to stimulate inflammation and fibrotic processes. This study shows an increased expression of RHAMM in proinflammatory macrophages. Interfering with HA/RHAMM interactions using a 15-mer RHAMM-mimetic, HA-binding peptide, together with high-molecular-weight (HMW) HA reduced the expression and release of inflammatory markers and increased the expression of anti-inflammatory markers in proinflammatory macrophages. HA/RHAMM interactions were interfered in vivo during the regeneration of a full-thickness cartilage defect after microfracture surgery in rabbits using three intra-articular injections of 15-mer RHAMM-mimetic. HA-binding peptide together with HMWHA reduced the number of proinflammatory macrophages and increased the number of anti-inflammatory macrophages in the injured knee joint and greatly improved the repair of the cartilage defect compared with intra-articular injections of HMWHA alone. These findings suggest that HA/RHAMM interactions play a key role in cartilage repair/regeneration via stimulating inflammatory and fibrotic events, including increasing the ratio of proinflammatory/anti-inflammatory macrophages. Interfering with these interactions reduced inflammation and greatly improved cartilage repair.
PMID: 38403161
ISSN: 1525-2191
CID: 5655522
Binding requirements for latent transforming growth factor Beta2 activation
Although the mechanism for activation of latent TGFβ1 and TGFβ3 is understood to involve the binding of the TGFβ propeptide (LAP) to both an integrin and an insoluble substrate, the activation of latent TGFβ2 has been unclear because the TGFβ2 LAP does not have the classical integrin binding sequence found in the other two TGFβ isoform LAPs. To assess the potential requirement for covalent linkage with a matrix or cell surface protein for the activation of latent TGFβ2, we generated mice in which the TGFβ2 Cys residue predicted to be involved in binding was mutated to Ser (Tgfb2C24S
PMCID:11145359
PMID: 38831847
ISSN: 2590-0285
CID: 5665132
OTA international : the open access journal of orthopaedic trauma. 2024:7(4 Suppl).DOI: 10.1097/OI9.0000000000000309
Prevention and treatment of osteomyelitis after open tibia fractures
Infection and chronic post-traumatic osteomyelitis of the tibia after open fracture are complex problems that cause significant morbidity and threaten the viability of a limb. Therefore, it is of utmost importance for the orthopaedic surgeon to understand both patient and treatment factors that modify the risk of developing these disastrous complications. Infection risk is largely based on severity of open injury in addition to inherent patient factors. Orthopaedic surgeons can work to mitigate this risk with prompt antibiotic administration, thorough and complete debridement, expedient fracture stabilization, and early wound closure. In the case osteomyelitis does occur, the surgeon should use a systematic multidisciplinary approach for eradication.
PMCID:11149744
PMID: 38840709
ISSN: 2574-2167
CID: 5665502
scRNA-seq reveals transcriptional dynamics of Encephalitozoon intestinalis parasites in human macrophages
Microsporidia are single-celled intracellular parasites that cause opportunistic diseases in humans. Encephalitozoon intestinalis is a prevalent human-infecting species that invades the small intestine. Dissemination to other organ systems is also observed, and is potentially facilitated by macrophages. The macrophage response to infection and the developmental trajectory of the parasite are not well studied. Here we use single cell RNA sequencing to investigate transcriptional changes in both the host and parasite during infection. While a small population of infected macrophages mount a response, most remain transcriptionally unchanged, suggesting that the majority of parasites may avoid host detection. The parasite transcriptome reveals large transcriptional changes throughout the life cycle, providing a blueprint for parasite development. The stealthy microsporidian lifestyle likely allows these parasites to harness macrophages for replication and dissemination. Together, our data provide insights into the host response in primary human macrophages and the E. intestinalis developmental program.
PMCID:11160751
PMID: 38853846
CID: 5668742
Extracellular Vesicles: Bridging the Heart and Tumor in Reverse Cardio-Oncology [Comment]
PMID: 38805582
ISSN: 1524-4539
CID: 5663422
Modulation of GPR133 (ADGRD1) signaling by its intracellular interaction partner extended synaptotagmin 1
GPR133 (ADGRD1) is an adhesion G-protein-coupled receptor that signals through Gαs/cyclic AMP (cAMP) and is required for the growth of glioblastoma (GBM), an aggressive brain malignancy. The regulation of GPR133 signaling is incompletely understood. Here, we use proximity biotinylation proteomics to identify ESYT1, a Ca2+-dependent mediator of endoplasmic reticulum-plasma membrane bridge formation, as an intracellular interactor of GPR133. ESYT1 knockdown or knockout increases GPR133 signaling, while its overexpression has the opposite effect, without altering GPR133 levels in the plasma membrane. The GPR133-ESYT1 interaction requires the Ca2+-sensing C2C domain of ESYT1. Thapsigargin-mediated increases in cytosolic Ca2+ relieve signaling-suppressive effects of ESYT1 by promoting ESYT1-GPR133 dissociation. ESYT1 knockdown or knockout in GBM slows tumor growth, suggesting tumorigenic functions of ESYT1. Our findings demonstrate a mechanism for the modulation of GPR133 signaling by increased cytosolic Ca2+, which reduces the signaling-suppressive interaction between GPR133 and ESYT1 to raise cAMP levels.
PMID: 38758649
ISSN: 2211-1247
CID: 5663132
Proton-coupled transport mechanism of the efflux pump NorA
Efflux pump antiporters confer drug resistance to bacteria by coupling proton import with the expulsion of antibiotics from the cytoplasm. Despite efforts there remains a lack of understanding as to how acid/base chemistry drives drug efflux. Here, we uncover the proton-coupling mechanism of the Staphylococcus aureus efflux pump NorA by elucidating structures in various protonation states of two essential acidic residues using cryo-EM. Protonation of Glu222 and Asp307 within the C-terminal domain stabilized the inward-occluded conformation by forming hydrogen bonds between the acidic residues and a single helix within the N-terminal domain responsible for occluding the substrate binding pocket. Remarkably, deprotonation of both Glu222 and Asp307 is needed to release interdomain tethering interactions, leading to opening of the pocket for antibiotic entry. Hence, the two acidic residues serve as a "belt and suspenders" protection mechanism to prevent simultaneous binding of protons and drug that enforce NorA coupling stoichiometry and confer antibiotic resistance.
PMCID:11130294
PMID: 38802368
ISSN: 2041-1723
CID: 5663352
Upregulation of the AMPK-FOXO1-PDK4 pathway is a primary mechanism of pyruvate dehydrogenase activity reduction in tafazzin-deficient cells
Barth syndrome (BTHS) is a rare disorder caused by mutations in the TAFAZZIN gene. Previous studies from both patients and model systems have established metabolic dysregulation as a core component of BTHS pathology. In particular, features such as lactic acidosis, pyruvate dehydrogenase (PDH) deficiency, and aberrant fatty acid and glucose oxidation have been identified. However, the lack of a mechanistic understanding of what causes these conditions in the context of BTHS remains a significant knowledge gap, and this has hindered the development of effective therapeutic strategies for treating the associated metabolic problems. In the current study, we utilized tafazzin-knockout C2C12 mouse myoblasts (TAZ-KO) and cardiac and skeletal muscle tissue from tafazzin-knockout mice to identify an upstream mechanism underlying impaired PDH activity in BTHS. This mechanism centers around robust upregulation of pyruvate dehydrogenase kinase 4 (PDK4), resulting from hyperactivation of AMP-activated protein kinase (AMPK) and subsequent transcriptional upregulation by forkhead box protein O1 (FOXO1). Upregulation of PDK4 in tafazzin-deficient cells causes direct phospho-inhibition of PDH activity accompanied by increased glucose uptake and elevated intracellular glucose concentration. Collectively, our findings provide a novel mechanistic framework whereby impaired tafazzin function ultimately results in robust PDK4 upregulation, leading to impaired PDH activity and likely linked to dysregulated metabolic substrate utilization. This mechanism may underlie previously reported findings of BTHS-associated metabolic dysregulation.
PMCID:11106297
PMID: 38769106
ISSN: 2045-2322
CID: 5654252
Journal of the American Academy of Orthopaedic Surgeons. 2024:32(10):e476-e481.DOI: 10.5435/JAAOS-D-24-00020
Technology Behind Cell Therapy Augmentation of Fracture Healing: Concentrated Bone Marrow Aspirate
With an aging population, and an anticipated increase in overall fracture incidence, a sound understanding of bone healing and how technology can optimize this process is crucial. Concentrated bone marrow aspirate (cBMA) is a technology that capitalizes on skeletal stem and progenitor cells (SSPCs) to enhance the regenerative capacity of bone. This overview highlights the science behind cBMA, discusses the role of SSPCs in bone homeostasis and fracture repair, and briefly details the clinical evidence supporting the use of cBMA in fracture healing. Despite promising early clinical results, a lack of standardization in harvest and processing techniques, coupled with patient variability, presents challenges in optimizing the use of cBMA. However, cBMA remains an emerging technology that may certainly play a crucial role in the future of fracture healing augmentation.
PMID: 38700858
ISSN: 1940-5480
CID: 5655982
