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PLoS Biology Jul 2024Episodic memory is essential to navigate in a changing environment by recalling past events, creating new memories, and updating stored information from experience....
Episodic memory is essential to navigate in a changing environment by recalling past events, creating new memories, and updating stored information from experience. Although the mechanisms for acquisition and consolidation have been profoundly studied, much less is known about memory retrieval. Hippocampal spatial representations are key for retrieval of contextually guided episodic memories. Indeed, hippocampal place cells exhibit stable location-specific activity which is thought to support contextual memory, but can also undergo remapping in response to environmental changes. It is unclear if remapping is directly related to the expression of different episodic memories. Here, using an incidental memory recognition task in rats, we showed that retrieval of a contextually guided memory is reflected by the levels of CA3 remapping, demonstrating a clear link between external cues, hippocampal remapping, and episodic memory retrieval that guides behavior. Furthermore, we describe NMDARs as key players in regulating the balance between retrieval and memory differentiation processes by controlling the reactivation of specific memory traces. While an increase in CA3 NMDAR activity boosts memory retrieval, dentate gyrus NMDAR activity enhances memory differentiation. Our results contribute to understanding how the hippocampal circuit sustains a flexible balance between memory formation and retrieval depending on the environmental cues and the internal representations of the individual. They also provide new insights into the molecular mechanisms underlying the contributions of hippocampal subregions to generate this balance.
PubMed: 38950066
DOI: 10.1371/journal.pbio.3002706 -
Microbiology Spectrum Jul 2024Bacteriophages (hereafter "phages") are ubiquitous predators of bacteria in the natural world, but interest is growing in their development into antibacterial therapy as...
UNLABELLED
Bacteriophages (hereafter "phages") are ubiquitous predators of bacteria in the natural world, but interest is growing in their development into antibacterial therapy as complement or replacement for antibiotics. However, bacteria have evolved a huge variety of antiphage defense systems allowing them to resist phage lysis to a greater or lesser extent. In addition to dedicated phage defense systems, some aspects of the general stress response also impact phage susceptibility, but the details of this are not well known. In order to elucidate these factors in the opportunistic pathogen , we used the laboratory-conditioned strain PAO1 as host for phage infection experiments as it is naturally poor in dedicated phage defense systems. Screening by transposon insertion sequencing indicated that the uncharacterized operon PA3040-PA3042 was potentially associated with resistance to lytic phages. However, we found that its primary role appeared to be in regulating biofilm formation, particularly in a clinical isolate of in which it also altered tobramycin resistance. Its expression was highly growth-phase dependent and responsive to phage infection and cell envelope stress. Our results suggest that this operon may be a cryptic but important locus for stress tolerance.
IMPORTANCE
An important category of bacterial stress response systems is bacteriophage defense, where systems are triggered by bacteriophage infection and activate a response which may either destroy the phage genome or destroy the infected cell so that the rest of the population survives. In some bacteria, the cell envelope stress response is activated by bacteriophage infection, but it is unknown whether this contributes to the survival of the infection. We have found that a conserved uncharacterized operon (PA3040-PA3042) of the cell envelope stress regulon in , which has very few dedicated phage defense systems, responds to phage infection and stationary phase as well as envelope stress and is important for growth and biofilm formation in a clinical isolate of , even in the absence of phages. As homologs of these genes are found in other bacteria, they may be a novel component of the general stress response.
PubMed: 38949386
DOI: 10.1128/spectrum.03875-23 -
The Journal of Clinical Investigation Jul 2024Biological sex is an important modifier of physiology and influences pathobiology in many diseases. While heart disease is the number one cause of death worldwide in... (Review)
Review
Biological sex is an important modifier of physiology and influences pathobiology in many diseases. While heart disease is the number one cause of death worldwide in both men and women, sex differences exist at the organ and cellular scales, affecting clinical presentation, diagnosis, and treatment. In this Review, we highlight baseline sex differences in cardiac structure, function, and cellular signaling and discuss the contribution of sex hormones and chromosomes to these characteristics. The heart is a remarkably plastic organ and rapidly responds to physiological and pathological cues by modifying form and function. The nature and extent of cardiac remodeling in response to these stimuli are often dependent on biological sex. We discuss organ- and molecular-level sex differences in adaptive physiological remodeling and pathological cardiac remodeling from pressure and volume overload, ischemia, and genetic heart disease. Finally, we offer a perspective on key future directions for research into cardiac sex differences.
Topics: Humans; Female; Male; Sex Characteristics; Ventricular Remodeling; Animals; Heart Diseases; Gonadal Steroid Hormones; Heart; Myocardium
PubMed: 38949027
DOI: 10.1172/JCI180074 -
The Journal of Clinical Investigation Jul 2024Type 3 innate lymphoid cells (ILC3s) are key regulators of intestinal homeostasis and epithelial barrier integrity. In this issue of the JCI, Cao and colleagues found...
Type 3 innate lymphoid cells (ILC3s) are key regulators of intestinal homeostasis and epithelial barrier integrity. In this issue of the JCI, Cao and colleagues found that a sensor of endoplasmic reticulum (ER) stress, the inositol-requiring kinase 1α/X-box-binding protein 1 (IRE1α/XBP1) pathway, fine-tuned the functions of ILC3s. Activation of IRE1α and XBP1 in ILC3s limited intestinal inflammation in mice and correlated with the efficacy of ustekinumab, an IL-12/IL-23 blocker, in patients with Crohn's disease. These results advance our understanding in the use of ILCs as biomarkers not only to predict disease outcomes but also to indicate the response to biologicals in patients with inflammatory bowel disease.
Topics: X-Box Binding Protein 1; Animals; Endoribonucleases; Protein Serine-Threonine Kinases; Humans; Mice; Endoplasmic Reticulum Stress; Lymphocytes; Signal Transduction; Crohn Disease; Immunity, Innate; Inflammation
PubMed: 38949019
DOI: 10.1172/JCI182204 -
HemaSphere Jul 2024Bridging therapy (BT) after leukapheresis is required in most relapsed/refractory (R/R) large B-cell lymphoma (LBCL) patients receiving chimeric antigen receptor (CAR) T...
Bridging therapy (BT) after leukapheresis is required in most relapsed/refractory (R/R) large B-cell lymphoma (LBCL) patients receiving chimeric antigen receptor (CAR) T cells. Bendamustine-containing regimens are a potential BT option. We aimed to assess if this agent had a negative impact on CAR-T outcomes when it was administered as BT. We included R/R LBCL patients from six centers who received systemic BT after leukapheresis from February 2019 to September 2022; patients who only received steroids or had pre-apheresis bendamustine exposure were excluded. Patients were divided into two BT groups, with and without bendamustine. Separate safety and efficacy analyses were carried out for axi-cel and tisa-cel. Of 243 patients who received BT, bendamustine (benda) was included in 62 (26%). There was a higher rate of BT progressors in the non-benda group (62% vs. 45%, = 0.02). Concerning CAR-T efficacy, complete responses were comparable for benda versus non-benda BT cohorts with axi-cel (70% vs. 53%, = 0.12) and tisa-cel (44% vs. 36%, = 0.70). Also, 12-month progression-free and overall survival were not significantly different between BT groups with axi-cel (56% vs. 43% and 71% vs. 63%) and tisa-cel (25% vs. 26% and 52% vs. 48%); there were no differences when BT response was considered. CAR T-cell expansion for each construct was similar between BT groups. Regarding safety, CRS G ≥3 (6% vs. 6%, = 0.79), ICANS G ≥3 (15% vs. 17%, = 0.68), severe infections, and neutropenia post-infusion were comparable among BT regimens. BT with bendamustine-containing regimens is safe for patients requiring disease control during CAR T-cell manufacturing.
PubMed: 38948924
DOI: 10.1002/hem3.86 -
Molecular Therapy. Oncology Jun 2024The presence of a poly(A) tail is indispensable for the post-transcriptional regulation of gene expression in cancer. This dynamic and modifiable feature of transcripts...
The presence of a poly(A) tail is indispensable for the post-transcriptional regulation of gene expression in cancer. This dynamic and modifiable feature of transcripts is under the control of various nuclear and cytoplasmic proteins. This study aimed to develop a novel cytoplasmic poly(A)-related signature for predicting prognosis, clinical attributes, tumor immune microenvironment (TIME), and treatment response in hepatocellular carcinoma (HCC). Utilizing RNA sequencing (RNA-seq) data from The Cancer Genome Atlas (TCGA), non-negative matrix factorization (NMF), and principal-component analysis (PCA) were employed to categorize HCC patients into three clusters, thus demonstrating the pivotal prognostic role of cytoplasmic poly(A) tail regulators. Furthermore, machine learning algorithms such as least absolute shrinkage and selection operator (LASSO), survival analysis, and Cox proportional hazards modeling were able to distinguish distinct cytoplasmic poly(A) subtypes. As a result, a 5-gene signature derived from TCGA was developed and validated using International Cancer Genome Consortium (ICGC) HCC datasets. This novel classification based on cytoplasmic poly(A) regulators has the potential to improve prognostic predictions and provide guidance for chemotherapy, immunotherapy, and transarterial chemoembolization (TACE) in HCC.
PubMed: 38948919
DOI: 10.1016/j.omton.2024.200816 -
BioRxiv : the Preprint Server For... Jun 2024Alcohol consumption produces acute analgesic effects, and people experiencing pain conditions may drink alcohol to alleviate discomfort. However, tolerance to the...
Alcohol consumption produces acute analgesic effects, and people experiencing pain conditions may drink alcohol to alleviate discomfort. However, tolerance to the analgesic properties of alcohol could prompt escalating consumption and dependence. Both nociception and alcohol-induced analgesia are under significant genetic control. Understanding the genetic architecture of these processes could inform better treatment options for people with pain conditions. This study aims to identify quantitative trait loci (QTL) driving variation in ethanol-induced analgesia across BXD recombinant inbred mouse lines. Male and female mice from 62 BXD strains received ethanol or saline oral gavage for five days and were tested for hot plate (HP) latency at baseline, Day 1, and Day 5. QTL mapping of HP phenotypes identified a significant provisional QTL on chromosome 17 for Day 1 HP latency in mice receiving ethanol. An additional highly suggestive QTL was present on chromosome 9 for the difference in pre- and post-ethanol thermal nociception. Candidate genes within QTL support intervals were provisionally identified using HP phenotypic correlations to transcriptomic database, expression QTL analysis, and other bioinformatics inquiries. The combined behavioral and bioinformatic analyses yielded strong ethanol analgesia candidate genes, specifically . Thus, the results of this genetic study of ethanol-induced analgesia in BXD mouse strains may contribute significantly to our understanding of the molecular basis for individual variation in the analgesic response to acute ethanol.
PubMed: 38948869
DOI: 10.1101/2024.06.17.599372 -
BioRxiv : the Preprint Server For... Jun 2024Under stress conditions, cells reprogram their molecular machineries to mitigate damage and promote survival. Ubiquitin signaling is globally increased during oxidative...
Under stress conditions, cells reprogram their molecular machineries to mitigate damage and promote survival. Ubiquitin signaling is globally increased during oxidative stress, controlling protein fate and supporting stress defenses at several subcellular compartments. However, the rules driving subcellular ubiquitin localization to promote these concerted response mechanisms remain understudied. Here, we show that K63-linked ubiquitin chains, known to promote proteasome-independent pathways, accumulate primarily in non-cytosolic compartments during oxidative stress induced by sodium arsenite in mammalian cells. Our subcellular ubiquitin proteomic analyses of non-cytosolic compartments expanded 10-fold the pool of proteins known to be ubiquitinated during arsenite stress (2,046) and revealed their involvement in pathways related to immune signaling and translation control. Moreover, subcellular proteome analyses revealed proteins that are recruited to non-cytosolic compartments under stress, including a significant enrichment of helper ubiquitin-binding adaptors of the ATPase VCP that processes ubiquitinated substrates for downstream signaling. We further show that VCP recruitment to non-cytosolic compartments under arsenite stress occurs in a ubiquitin-dependent manner mediated by its adaptor NPLOC4. Additionally, we show that VCP and NPLOC4 activities are critical to sustain low levels of non-cytosolic K63-linked ubiquitin chains, supporting a cyclical model of ubiquitin conjugation and removal that is disrupted by cellular exposure to reactive oxygen species. This work deepens our understanding of the role of localized ubiquitin and VCP signaling in the basic mechanisms of stress response and highlights new pathways and molecular players that are essential to reshape the composition and function of the human subcellular proteome under dynamic environments.
PubMed: 38948861
DOI: 10.1101/2024.06.20.598218 -
BioRxiv : the Preprint Server For... Jun 2024is an opportunistic fungal pathogen responsible for >150,000 deaths every year with a mortality rate as high as 81%. This high medical burden is due, in part, to an...
UNLABELLED
is an opportunistic fungal pathogen responsible for >150,000 deaths every year with a mortality rate as high as 81%. This high medical burden is due, in part, to an incomplete understanding of its pathogenesis. In a previous study, we identified a cryptococcal atypical pleiotropic drug resistance (PDR) transporter, , that regulated antifungal resistance and host interactions. Here, we follow-up on the role of in cryptococcal virulence. , mice infected with the Δ strain display altered symptomatology and disease progression. Specifically, we observed a significant increase in the innate immune cell populations in the Δ-infected mice when compared to their WT-infected littermates. Furthermore, quantification of pulmonary cytokines/chemokines revealed a robust increase of pro-inflammatory cytokines in mice infected with the Δ mutant strain. Whereas antifungal treatment of Δ-infected animals did not affect survival, treatment with a corticosteroid significantly extended survival, highlighting the importance of a balanced/controlled host immune response. We determined that the hyper-inflammatory immune response occurs, in part, because the loss of the Pdr6 transporter indirectly alters the cryptococcal cell wall architecture and results in the increased exposure of chitin, β-glucan, and other cryptococcal-specific pathogen associated molecular patterns. Taken together, this study provides clinical insights regarding cryptococcal pathogenesis while also providing additional functions of PDR-type ATP-binding cassette (ABC) transporters in pathogenic fungi.
IMPORTANCE
Yeasts of the genus, especially , can cause disease with unacceptably high mortality. This is due to delays in diagnostics, ineffective treatments, and an incomplete understanding of the interactions between this fungus and our immune system. In this study, we expand our knowledge of the biological function of the gene, particularly its effect on modulating the host's immune response. Normally, 's infections are characterized by an anti-inflammatory response that is unable to control the yeast. In the absence of , the response to the infection is a dysregulated pro-inflammatory response that initially controls the fungi but eventually results in death of the host due to too much tissue damage. This is due, in part, to an altered fungal surface. Given the dual role of in modulating antifungal sensitivity and immune responses, this work provides important insights that may lead to new or improved therapeutics.
PubMed: 38948814
DOI: 10.1101/2024.06.17.599354 -
BioRxiv : the Preprint Server For... Jun 2024Solid carcinomas are often highly heterogenous cancers, arising from multiple epithelial cells of origin. Yet, how the cell of origin influences the response of the...
Solid carcinomas are often highly heterogenous cancers, arising from multiple epithelial cells of origin. Yet, how the cell of origin influences the response of the tumor microenvironment is poorly understood. Lung adenocarcinoma (LUAD) arises in the distal alveolar epithelium which is populated primarily by alveolar epithelial type I (AT1) and type II (AT2) cells. It has been previously reported that AT1 cells can give rise to a histologically-defined LUAD that is distinct in pathology and transcriptomic identity from that arising from AT2 cells . To determine how cells of origin influence the tumor immune microenvironment (TIME) landscape, we comprehensively characterized transcriptomic, molecular, and cellular states within the TIME of AT1 and AT2-derived LUAD using KRAS oncogenic driver mouse models. Myeloid cells within the AT1-derived LUAD TIME were increased, specifically, immunoreactive monocytes and tumor associated macrophages (TAMs). In contrast, the AT2 LUAD TIME was enriched for Arginase-1 myeloid derived suppressor cells (MDSC) and TAMs expressing profiles suggestive of immunosuppressive function. Validation of immune infiltration was performed using flow cytometry, and intercellular interaction analysis between the cells of origin and major myeloid cell populations indicated that cell-type specific markers SFTPD in AT2 cells and CAV1 in AT1 cells mediated unique interactions with myeloid cells of the differential immunosuppressive states within each cell of origin mouse model. Taken together, AT1-derived LUAD presents with an anti-tumor, immunoreactive TIME, while the TIME of AT2-derived LUAD has hallmarks of immunosuppression. This study suggests that LUAD cell of origin influences the composition and suppression status of the TIME landscape and may hold critical implications for patient response to immunotherapy.
PubMed: 38948812
DOI: 10.1101/2024.06.19.599651