Fructose Stimulated De Novo Lipogenesis Is Promoted by Inflammation
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Non-alcoholic fatty liver disease (NAFD) affects 30% of adult Americans. While NAFD starts as simple steatosis with little liver damage, its severe manifestation as non-alcoholic steatohepatitis (NASH) is a leading cause of liver failure, cirrhosis, and cancer. Fructose consumption is proposed to increase the risk of hepatosteatosis and NASH. Excessive intake of fructose causes barrier deterioration and low-grade endotoxemia. Using a mouse model, the study examined the mechanism of how fructose triggers these alterations and their roles in hepatosteatosis and NASH pathogenesis.
Antiretroviral Therapy Timing Impacts Latent Tuberculosis Infection Reactivation in a Tuberculosis/Simian Immunodeficiency Virus Coinfection Model
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In the rhesus macaque model for Mycobacterium tuberculosis plus simian immunodeficiency virus (SIV) co-infection, chronic immune activation rather than depletion of CD4+ T cells correlates with reactivation of latent tuberculosis infection (LTBI). Researchers administered combined antiretroviral therapy (cART) at 2 weeks post-SIV co-infection to study whether restoration of CD4+ T cell immunity occurred more broadly, and whether this prevented LTBI compared to cART initiated at 4 weeks post-SIV.
An NR2F1-Specific Agonist Suppresses Metastasis by Inducing Cancer Cell Dormancy
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Researchers described the discovery of a nuclear receptor NR2F1 antagonist that specifically activates dormancy programs in malignant cells. Agonist treatment resulted in a self-regulated increase in NR2F1 mRNA and protein and downstream transcription of a novel dormancy program. This program led to growth arrest in multiple human cell lines, as well as patient-derived organoids. This effect was lost when NR2F1 was knocked out. In mice, agonist treatment resulted in inhibition of lung metastasis of head and neck squamous cell carcinomas, even after cessation of the treatment.
Selective G Protein Signaling Driven by Substance P–Neurokinin Receptor Dynamics
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Investigators determined the cryogenic-electron microscopy structures of active neurokinin-1 receptor (NK1R) bound to neuropeptide substance P (SP) or the G protein q (Gq)-biased peptide SP6–11. Peptide interactions deep within NK1R are critical for receptor activation. Conversely, interactions between SP and NK1R extracellular loops are required for potent Gs-signaling but not Gq-signaling. Molecular dynamics simulations showed that these superficial contacts restrict SP flexibility. SP6–11, which lacks these interactions, is dynamic while bound to NK1R.
Integrated Spatial Multiomics Reveals Fibroblast Fate During Tissue Repair
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The function of regenerative medicine in wound healing remains elusive, partially because of how fibroblasts program and respond to injury remains unclear. Investigators presented a multimodal -omics platform for the comprehensive study of cell populations in complex tissue, which allowed characterization of cells involved in wound healing across time and space. Through integrated analysis of single cell chromatin landscapes and gene expression states, coupled with spatial transcriptomic profiling, fibroblast epigenomes were imputed with temporospatial resolution.
A Novel Non-Human Primate Model of Pelizaeus-Merzbacher Disease
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Pelizaeus-Merzbacher disease (PMD) in humans is a severe hypomyelinating disorder of the central nervous system (CNS) linked to mutations in the proteolipid protein-1 (PLP1) gene. Investigators report on three spontaneous cases of male neonatal rhesus macaques (RMs) with clinical symptoms of hypomyelinating disease. Genetic analysis revealed that the parents of these related RMs carried a rare, hemizygous missense variant in exon 5 of the PLP1 gene.
A Noncoding RNA Modulator Potentiates Phenylalanine Metabolism in Mice
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The role of long noncoding RNAs (lncRNAs) in phenylketonuria (PKU), an inherited disorder causing build-up of an amino acid causing brain problems, is unknown. Investigators demonstrated that the mouse lncRNA Pair and human lncRNA HULC associate with phenylalanine hydroxylase (PAH). Pair-knockout mice exhibited phenotypes that faithfully models human PKU, such as excessive blood phenylalanine (Phe), growth retardation, and progressive neurological symptoms.
Sexual Dimorphic Impact of Adult-Onset Somatopause on Life Span and Age-Induced Osteoarthritis
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Osteoarthritis (OA) is a major cause of disability worldwide. In humans, the age-associated decline in growth hormone (GH) levels was hypothesized to play a role in the etiology of OA. Investigators studied the impact of adult-onset isolated GH deficiency (AOiGHD) on the life span and skeletal integrity in aged mice. Reductions in GH during adulthood were associated with extended life span and reductions in body temperature in female mice only. However, end-of-life pathology revealed high levels of lymphomas in both sexes, independent of GH status.
Systems Vaccinology of the BNT162b2 mRNA Vaccine in Humans
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It was poorly understood how mRNA vaccines against SARS-CoV-2 stimulate protective immune responses. To address this, researchers comprehensively profiled innate and adaptive immune responses of healthy volunteers vaccinated with the Pfizer-BioNTech mRNA vaccine (BNT162b2). Vaccination resulted in robust production of neutralizing antibodies against wild-type SARS-CoV-2, to a lesser extent, the beta variant, as well as significant increases in antigen-specific polyfunctional CD4+ and CD8+ T cells after the second dose.
Phase Separation Drives Aberrant Chromatin Looping and Cancer Development
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How unstructured intrinsically disordered regions (IDRs) contribute to oncogenesis is elusive. Using an Orbitrap fusion tribrid mass spectrometer, investigators show that IDRs contained within NUP98–HOXA9, a homeodomain-containing transcription factor chimera recurrently detected in leukaemias, are essential for establishing liquid–liquid phase separation (LLPS) puncta of chimera and for inducing leukaemic transformation.