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6
Date Added: Sep 28, 2021
Date Added: Sep 28, 2021
Pediatric COVID-19 (pCOVID-19) is rarely severe, however a minority of SARS-CoV-2-infected children may develop MIS-C, a multisystem inflammatory syndrome with significant morbidity. In this longitudinal multi-institutional study, we used multi-omics to identify novel time- and treatment-related immunopathological signatures in children with COVID-19 (n=105) and MIS-C (n=76). pCOVID-19 was characterized by enhanced type I IFN responses, and MIS-C by type II IFN- and NF-κB dependent responses, matrisome activation, and increased levels of Spike protein. Reduced levels of IL-33 in pCOVID-19, and of CCL22 in MIS-C suggested suppression of Th2 responses. Expansion of TRBV11-2 T-cell clonotypes in MIS-C was associated with inflammation and signatures of T-cell activation, and was reversed by glucocorticoids. The association of MIS-C with the combination of HLA A*02, B*35, C*04 alleles suggests genetic susceptibility. MIS-C B cells showed higher mutation load. Use of IVIG was identified as a confounding factor in the interpretation of autoantibody levels.
7
Date Added: Oct 5, 2021
Date Added: Oct 5, 2021
The brain tumor glioblastoma (GBM) remains one of the most aggressive and devastating tumors despite decades of effort to find more effective treatments. A hallmark of GBM is the constitutive activation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappaB) signaling pathway, which regulates cell proliferation, inflammation, migration and apoptosis. The prolyl isomerase, Pin1, has been found to bind directly to the NF-kappaB protein, p65, and cause increases in NF-kappaB promoter activity in a breast cancer model. We now present evidence that this interaction occurs in GBM and that it has important consequences on NF-kappaB signaling. We demonstrate that Pin1 levels are enhanced in primary GBM tissues compared with controls, and that this difference in Pin1 expression affects the migratory capacity of GBM-derived cells. Pin1 knockdown decreases the amount of activated, phosphorylated p65 in the nucleus, resulting in inhibition of the transcriptional program of the IL-8 gene. Through the use of microarray, we also observed changes in the expression levels of other NF-kappaB regulated genes due to Pin1 knockdown. Taken together, these data suggest that Pin1 is an important regulator of NF-kappaB in GBM, and support the notion of using Pin1 as a therapeutic target in the future.
16
Date Added: Jul 21, 2021
Date Added: Jul 21, 2021
Biodiversity is the variety of different forms of life on earth, including the different plants, animals, micro-organisms, the genes they contain and the ecosystem they form. It refers to genetic variation, ecosystem variation, species variation (number of species) within an area, biome or planet. Relative to the range of habitats, biotic communities and ecological processes in the biosphere, biodiversity is vital in a number of ways including promoting the aesthetic value of the natural environment, contribution to our material well-being through utilitarian values by providing food, fodder, fuel, timber and medicine. Biodiversity is the life support system. Organisms depend on it for the air to breathe, the food to eat, and the water to drink. Wetlands filter pollutants from water, trees and plants reduce global warming by absorbing carbon, and bacteria and fungi break down organic material and fertilize the soil. It has been empirically shown that native species richness is linked to the health of ecosystems, as is the quality of life for humans. The ecosystem services of biodiversity is maintained through formation and protection of soil, conservation and purification of water, maintaining hydrological cycles, regulation of biochemical cycles, absorption and breakdown of pollutants and waste materials through decomposition, determination and regulation of the natural world climate. Despite the benefits from biodiversity, today’s threats to species and ecosystems are increasing day by day with alarming rate and virtually all of them are caused by human mismanagement of biological resources often stimulated by imprudent economic policies, pollution and faulty institutions in-addition to climate change. To ensure intra and intergenerational equity, it is important to conserve biodiversity. Some of the existing measures of biodiversity conservation include; reforestation, zoological gardens, botanical gardens, national parks, biosphere reserves, germplasm banks and adoption of breeding techniques, tissue culture techniques, social forestry to minimize stress on the exploitation of forest resources.
4
Date Added: Sep 23, 2021
Date Added: Sep 23, 2021
Background Cellular rejection after heart transplantation imparts significant morbidity and mortality. Current immunosuppressive strategies are imperfect, target recipient T-cells, and have a multitude of adverse effects. The innate immune response plays an essential role in the recruitment and activation of T-cells. Targeting the donor innate immune response would represent the earliest interventional opportunity within the immune response cascade. There is limited knowledge regarding donor immune cell types and functions in the setting of cardiac transplantation and no current therapeutics exist for targeting these cell populations. Methods Using genetic lineage tracing, cell ablation, and conditional gene deletion, we examined donor mononuclear phagocyte diversity and function during acute cellular rejection of transplanted hearts in mice. We performed single cell RNA sequencing on donor and recipient macrophages, dendritic cells, and monocytes at multiple timepoints after transplantation. Based on our single cell RNA sequencing data, we evaluated the functional relevance of donor CCR2+ and CCR2- macrophages using selective cell ablation strategies in donor grafts prior to transplant. Finally, we perform functional validation of our single cell-derived hypothesis that donor macrophages signal through MYD88 to facilitate cellular rejection. Results Donor macrophages persisted in the transplanted heart and co-existed with recipient monocyte-derived macrophages. Single-cell RNA sequencing identified donor CCR2+ and CCR2- macrophage populations and revealed remarkable diversity amongst recipient monocytes, macrophages, and dendritic cells. Temporal analysis demonstrated that donor CCR2+ and CCR2- macrophages were transcriptionally distinct, underwent significant morphologic changes, and displayed unique activation signatures after transplantation. While selective depletion of donor CCR2- macrophages reduced allograft survival, depletion of donor CCR2+ macrophages prolonged allograft survival. Pathway analysis revealed that donor CCR2+ macrophages were being activated through MYD88/NF-ĸβ signaling. Deletion of MYD88 in donor macrophages resulted in reduced antigen presenting cell recruitment, decreased emergence of allograft reactive T-cells, and extended allograft survival. Conclusions Distinct populations of donor and recipient macrophages co-exist within the transplanted heart. Donor CCR2+ macrophages are key mediators of allograft rejection and inhibition of MYD88 signaling in donor macrophages is sufficient to suppress rejection and extend allograft survival. This highlights the therapeutic potential of donor heart-based interventions.
66
Date Added: Jul 5, 2021
Date Added: Jul 5, 2021
An indispensable feature of episodic memory is our ability to temporally piece together different elements of an experience into a coherent memory. Hippocampal “time cells” – neurons that represent temporal information – may play a critical role in this process. While these cells have been repeatedly found in rodents, it is still unclear to what extent similar temporal selectivity exists in the human hippocampus. Here we show that temporal context modulates the firing activity of human hippocampal neurons during structured temporal experiences. We recorded neuronal activity in the human brain while patients of either sex learned predictable sequences of pictures. We report that human time cells fire at successive moments in this task. Furthermore, time cells also signaled inherently changing temporal contexts during empty 10-second gap periods between trials, while participants waited for the task to resume. Finally, population activity allowed for decoding temporal epoch identity, both during sequence learning and during the gap periods. These findings suggest that human hippocampal neurons could play an essential role in temporally organizing distinct moments of an experience in episodic memory. Significance Statement: Episodic memory refers to our ability to remember the “what, where, and when” of a past experience. Representing time is an important component of this form of memory. Here, we show that neurons in the human hippocampus represent temporal information. This temporal signature was observed both when participants were actively engaged in a memory task, as well as during 10s-long gaps when they were asked to wait before performing the task. Furthermore, the activity of the population of hippocampal cells allowed for decoding one temporal epoch from another. These results suggest a robust representation of time in the human hippocampus.
5
Date Added: Sep 15, 2021
Date Added: Sep 15, 2021
Over the last decade, nanoneedle-based systems have demonstrated to be extremely useful in cell biology. They can be used as nanotools for drug delivery, biosensing or biomolecular recognition inside cells; or they can be employed to select and sort in parallel a large number of living cells. When using these nanoprobes, the most important requirement is to minimize the cell damage, reducing the forces and indentation lengths needed to penetrate the cell membrane. This is normally achieved by reducing the diameter of the nanoneedles. However, several studies have shown that nanoneedles with a flat tip display lower penetration forces and indentation lengths. In this work, we have tested different nanoneedle shapes and diameters to reduce the force and the indentation length needed to penetrate the cell membrane, demonstrating that ultra-thin and sharp nanoprobes can further reduce them, consequently minimizing the cell damage.
17
Date Added: Sep 20, 2021
Date Added: Sep 20, 2021
Highlights •Bcl11a is expressed in a subset of murine and human dopaminergic neurons •Bcl11a+ dopaminergic neurons form a highly specific subcircuit in mouse •Bcl11a+ substantia nigra neurons are particularly vulnerable to neurodegeneration •Bcl11a inactivation increases vulnerability and impairs motor behavior in mice Summary Midbrain dopaminergic (mDA) neurons are diverse in their projection targets, effect on behavior, and susceptibility to neurodegeneration. Little is known about the molecular mechanisms establishing this diversity during development. We show that the transcription factor BCL11A is expressed in a subset of mDA neurons in the developing and adult murine brain and in a subpopulation of pluripotent-stem-cell-derived human mDA neurons. By combining intersectional labeling and viral-mediated tracing, we demonstrate that Bcl11a-expressing mDA neurons form a highly specific subcircuit within the murine dopaminergic system. In the substantia nigra, the Bcl11a-expressing mDA subset is particularly vulnerable to neurodegeneration upon α-synuclein overexpression or oxidative stress. Inactivation of Bcl11a in murine mDA neurons increases this susceptibility further, alters the distribution of mDA neurons, and results in deficits in skilled motor behavior. In summary, BCL11A defines mDA subpopulations with highly distinctive characteristics and is required for establishing and maintaining their normal physiology.
3
Date Added: Aug 4, 2021
Date Added: Aug 4, 2021
B-cell maturation antigen (BCMA)-targeted chimeric antigen receptor (CAR)-T-cell therapy is an emerging treatment option for multiple myeloma. The aim of this systematic review and meta-analysis was to determine its safety and clinical activity and to identify factors influencing these outcomes.
37
Date Added: May 24, 2021
Date Added: May 24, 2021
Transient induction of pluripotent reprogramming factors has been reported to reverse some features of aging in mammalian cells and tissues. However, the impact of transient reprogramming on somatic cell identity programs and the necessity of individual pluripotency factors remain unknown. Here, we mapped trajectories of transient reprogramming in young and aged cells from multiple murine cell types using single cell transcriptomics to address these questions. We found that transient reprogramming restored youthful gene expression in adipogenic cells and mesenchymal stem cells but also temporarily suppressed somatic cell identity programs. We further screened Yamanaka Factor subsets and found that many combinations had an impact on aging gene expression and suppressed somatic identity, but that these effects were not tightly entangled. We also found that a transient reprogramming approach inspired by amphibian regeneration restored youthful gene expression in aged myogenic cells. Our results suggest that transient pluripotent reprogramming poses a neoplastic risk, but that restoration of youthful gene expression can be achieved with alternative strategies.
5
Date Added: Aug 31, 2021
Date Added: Aug 31, 2021
TCR-like antibodies tackle celiac disease Ingestion of gluten-containing food triggers the gastrointestinal symptoms of celiac disease in patients with CD4+ T cells specific for deamidated gluten peptides presented by disease-associated HLA-DQ class II MHC molecules. Frick et al. used phage display technology to screen for TCR-like antibodies specific for an immunodominant gluten peptide bound by HLA-DQ2.5. Antibody engineering optimized affinity and binding stability, yielding an improved TCR-like antibody that structurally mimicked the TCR interface with gluten peptide–MHC complexes. These TCR-like antibodies blocked activation and proliferation of gluten-responsive human CD4+ T cells both in vitro and in DQ2.5 transgenic mice. TCR-like antibodies that block immunodominant epitope recognition have potential as personalized medicine treatments for blunting gluten-activated T cell responses without compromising effector functions provided by other T cells. Antibodies specific for peptides bound to human leukocyte antigen (HLA) molecules are valuable tools for studies of antigen presentation and may have therapeutic potential. Here, we generated human T cell receptor (TCR)–like antibodies toward the immunodominant signature gluten epitope DQ2.5-glia-α2 in celiac disease (CeD). Phage display selection combined with secondary targeted engineering was used to obtain highly specific antibodies with picomolar affinity. The crystal structure of a Fab fragment of the lead antibody 3.C11 in complex with HLA-DQ2.5:DQ2.5-glia-α2 revealed a binding geometry and interaction mode highly similar to prototypic TCRs specific for the same complex. Assessment of CeD biopsy material confirmed disease specificity and reinforced the notion that abundant plasma cells present antigen in the inflamed CeD gut. Furthermore, 3.C11 specifically inhibited activation and proliferation of gluten-specific CD4+ T cells in vitro and in HLA-DQ2.5 humanized mice, suggesting a potential for targeted intervention without compromising systemic immunity. A human TCR-like antibody blocks gluten-dependent activation of celiac disease T cells in vitro and in HLA-DQ2.5 humanized mice. A human TCR-like antibody blocks gluten-dependent activation of celiac disease T cells in vitro and in HLA-DQ2.5 humanized mice.