Macrophages Derived From Human Induced Pluripotent Stem Cells (iPSCs) Serve As a High-Fidelity Cellular Model for Investigating HIV-1, Dengue, and Influenza viruses
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Macrophages can be weaponized by viruses to host viral reproduction and support long-term persistence. The most common way of studying these cells is by isolating their precursors from donor blood and differentiating the isolated cells into macrophages. This method is costly and technically challenging, and it produces varying results. In this study, researchers confirmed that macrophages derived from iPSC cell lines—a model that is inexpensive, consistent, and modifiable by genome editing—are a suitable model for experiments involving HIV and other viruses.
Antiretroviral Therapy Reveals Triphasic Decay of Intact SIV Genomes and Persistence of Ancestral Variants
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Antiretroviral therapy (ART) halts HIV-1 replication but is not curative; a pool of latently infected CD4+ T cells persists, and viremia rapidly rebounds if ART is stopped. Using an intact proviral DNA assay, researchers characterized quantitative and qualitative changes in CD4+ T cells for 4 years following ART initiation in rhesus macaques of both sexes. They found that viruses replicating at ART initiation had mutations conferring antibody escape, and sequences with large numbers of antibody escape mutations became less abundant at later time points.
Blastocyst Development After Fertilization with In Vitro Spermatids Derived From Nonhuman Primate Embryonic Stem Cells
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Rhesus macaque pluripotent stem cells were differentiated into spermatogenic germ cell linages and matured in vitro to form spermatids that were capable of fertilizing oocytes (female or germ cells involved in reproduction) by intracytoplasmic spermatid injection (i.e., the egg is fertilized outside the body and the sperm is injected through a needle into the egg). Successful in vitro preimplantation embryo development was observed in approximately 12% of zygotes. The data suggest potential mechanisms to address male infertility.
Safety, Pharmacokinetics and Antiviral Activity of PGT121, a Broadly Neutralizing Monoclonal Antibody Against HIV-1: A Randomized, Placebo-Controlled, Phase 1 Clinical Trial
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Researchers carried out a double-blind trial of one administration of the HIV-1 V3-glycan-specific antibody (Ab) PGT121 in HIV-uninfected and HIV-infected adults on antiretroviral therapy (ART), as well as an open-label trial of one infusion of PGT121 in viremic HIV-infected adults not on ART. The investigators observed no treatment-related serious adverse events among the 48 participants, and neutralizing anti-drug Abs were not elicited. PGT121 reduced plasma HIV RNA by a median of 1.77 log in viremic participants.
The Bowfin Genome Illuminates the Developmental Evolution of Ray-Finned Fishes
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The bowfin (Amia calva) is a ray-finned fish that possesses a unique suite of ancestral and derived phenotypes, which are key to understanding vertebrate evolution. The phylogenetic position of bowfin as a representative of neopterygian fishes, its archetypical body plan and its unduplicated and slowly evolving genome make bowfin a central species for the genomic exploration of ray-finned fishes. Here the authors present a chromosome-level genome assembly for bowfin that enables gene-order analyses, settling long-debated neopterygian phylogenetic relationships.
Advancing Human Disease Research with Fish Evolutionary Mutant Models
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Model organism research is essential to understand disease mechanisms. However, laboratory-induced genetic models can lack genetic variation and often fail to mimic disease severity. Evolutionary mutant models (EMMs) are species with evolved phenotypes that mimic human disease. They have improved our understanding of cancer, diabetes, and aging. Fish are the most diverse group of vertebrates, exhibiting a kaleidoscope of specialized phenotypes, many that would be pathogenic in humans but are adaptive in the species' specialized habitat.
A Participant-Derived Xenograft Model of HIV Enables Long-Term Evaluation of Autologous Immunotherapies
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HIV-specific CD8+ T cells partially control viral replication but rarely provide lasting protection due to immune escape. Investigators showed that engrafting NSG mice with memory CD4+ T cells from HIV+ donors enables evaluation of autologous T cell responses while avoiding graft-versus-host disease. Treating HIV-infected mice with clinically relevant T cell products reduced viremia.
Bilateral Visual Projections Exist in Non-Teleost Bony Fish and Predate the Emergence of Tetrapods
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In most vertebrates, camera-style eyes contain retinal ganglion cell neurons that project to visual centers on both sides of the brain. However, in fish, ganglion cells were thought to innervate only the contralateral side, suggesting that bilateral visual projections appeared in tetrapods. Here, Vigouroux et al. showed that bilateral visual projections exist in non-teleost fishes and that the appearance of ipsilateral projections does not correlate with terrestrial transition or predatory behavior. However, overexpression of human ZIC2 induces ipsilateral visual projections in zebrafish.
The SARS-CoV-2 Receptor and Other Key Components of the Renin-Angiotensin-Aldosterone System Related to COVID-19 are Expressed in Enterocytes in Larval Zebrafish
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Hypertension and respiratory inflammation are exacerbated by the Renin-Angiotensin-Aldosterone System (RAAS), which normally protects from dropping blood pressure via Angiotensin II (Ang II) produced by the enzyme Ace. The Ace paralog Ace2 degrades Ang II and serves as the SARS-CoV-2 receptor. To exploit zebrafish to understand the relationship of RAAS to COVID-19, the group conducted genomic and phylogenetic analyses.
A Pulsatile Release Platform Based on Photo-Induced Imine-Crosslinking Hydrogel Promotes Scarless Wound Healing
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Skin wound healing is a dynamic and interactive process involving the collaborative efforts of growth factors, extracellular matrix (ECM), and different tissue and cell lineages. Although accumulating studies with a range of different model systems have increased our understanding of the cellular and molecular basis underlying skin scar formation, they have not been effectively translated to therapy. Development of effective therapeutic approaches for skin scar management is urgently needed.