Biology subjects

To, A.

Publications and source records attributed to To, A..

9 recordsLinked to original sources

bioRxiv2026

Atypical tetracyclines promote longevity and ferroptotic neuroprotection via translation attenuation

Preclinical and clinical studies have reported neuroprotective and geroprotective effects of tetracyclines that are independent of their antibiotic activity, but the underlying mechanisms remain unclear. Here, we systematically profile widely used tetracyclines, including impurities and degradation products, and identify translation attenuation as the shared driver of their neuroprotective and longevity-promoting effects, independent of classical tetracycline mechanisms. Instead, we uncover two mechanistically distinct classes of tetracyclines. Mitochondrial-targeting tetracyclines (MitoTets), exemplified by doxycycline, inhibit the mitochondrial ribosome and attenuate cytosolic translation through activation of the Integrated Stress Response (ISR). In contrast, atypical tetracyclines such as 4-epiminocycline and 12-aminominocycline act as cytosolic-targeting tetracyclines (CytoTets), directly inhibiting the cytosolic ribosome, bypassing the ISR, and protecting neurons from ferroptotic cell death. CytoTets are non-antibiotic, brain-penetrant, and neuroprotective in mouse and human neurons, establishing the tetracyclines as a tunable chemical scaffold for selectively targeting translation in aging and neurodegeneration. HighlightsO_LIThe tetracyclines broadly attenuate translation in multiple eukaryotic models C_LIO_LITranslation attenuation results from both ISR-dependent and ISR-independent mechanisms C_LIO_LIDiscovery of atypical, cytosolic targeting tetracyclines (CytoTETs) that protect from ferroptosis ISR-independently C_LIO_LICytoTETs inhibit translation and are neuroprotective in human-derived neurons and mouse hippocampus C_LI

pharmacology and toxicology↗

bioRxiv2025

Site-specific genome engineering of primary human natural killer cells for programmable anti-tumor function

Natural killer (NK) cells are emerging as a promising platform for engineered adoptive cell therapies. However, gene editing in NK cells remains challenging, and more effective strategies are needed. Here, we established a robust, feeder-free, and modular workflow for genome engineering in primary human NK cells, combining CRISPR/Cas9 with AAV6-mediated transgene delivery. Efficient site-specific transgene integration was achieved at various loci and can be coupled with concurrent disruption of the target locus in a single editing step. Furthermore, transgene expression was tunable according to the integration site and promoter. We applied this strategy to target a chimeric antigen receptor (CAR) transgene to a panel of inhibitory NK receptor loci, establishing a synergistic approach to enhance anti-tumor activity and facilitate the reliable comparison of CAR variants without expression bias. We identified TIGIT as an ideal locus that supports strong CAR expression and anti-tumor function. This genome engineering framework, which leverages multiple, complementary and precisely controlled genetic edits, can support the rational design of future NK-cell therapies tailored to overcome cell-intrinsic limitations and tumor-specific barriers.

immunology↗

bioRxiv2025

Divalent HIV-1 gp120 Immunogen Exhibits Selective Avidity for Broadly Neutralizing Antibody VRC01 Precursors

A major goal for the vaccine field is elicitation of broadly neutralizing antibodies (bnAbs) against pathogens that exhibit extensive antigenic diversity. In this study, we designed a rigid divalent immunogen for high avidity binding to the bnAb, VRC01, which targets the CD4 binding site (CD4bs) of HIV spike protein. This was accomplished by covalently linking two HIV-1 gp120 antigens to a complementary antibody and crosslinking the light chains. The divalent immunogen exhibits a higher affinity for VRC01-class antibodies compared to a non-Fab-Fab-crosslinked control, likely due to antigen pre-organization limiting the entropic penalty for divalent binding. Importantly, this immunogen exhibited divalent binding to VRC01 and monovalent binding to a non-CD4bs Ab, A32 - a characteristic we refer to as "selective avidity." This report supports future in vivo vaccination experiments to test the immune focusing properties of this immunogen, the results of which may suggest broad application of the selective avidity concept. Highlights- We designed a rigid divalent immunogen containing two copies of gp120 antigen - The gp120s are positioned to bind divalently to both Fabs of a target B cell receptor - The immunogen binds monovalently to non-target B cell receptors - This "selective avidity" effect may be used for immune focusing Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=162 SRC="FIGDIR/small/642120v1_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@169223eorg.highwire.dtl.DTLVardef@147152borg.highwire.dtl.DTLVardef@1bec911org.highwire.dtl.DTLVardef@828e73_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2024

Lipidic and senescent macrophages predict progression and response to combinatorial immunotherapy in triple-negative breast cancer

Immune cell subsets in the tumor predict prognosis. Identifying reliable subsets consistently in multiple patients is clinically important. Whats more advantageous to the field is if such subsets can be a target of immunotherapy. Here we analyzed single-cell RNA-sequencing datasets of patients with triple-negative breast cancer and identified APOE or FABP5-expressing macrophages correlated with poor prognosis. Further validation with TCGA-BRCA cohort detailed molecular signatures of these macrophages as lipidic and senescent. Our receptor-ligand mapping identified lipidic and senescent macrophages both suppress T-lymphoid and myeloid immunogenicity. Finally, we discovered that immune checkpoint therapy combined with chemotherapy reprogrammed anti-tumor microenvironment enriched with FOLR2+ macrophages facilitated T-cell activations. This suggests that lipidic and senescent macrophages could be a therapeutic target of immune checkpoint therapy.

cancer biology↗

bioRxiv2024

SARS-CoV-2 infection activates inflammatory macrophages in vascular immune organoids

SARS-CoV-2 provokes devastating tissue damage by cytokine release syndrome and leads to multi-organ failure. Modeling the process of immune cell activation and subsequent tissue damage is a significant task. Organoids from human tissues advanced our understanding of SARS-CoV-2 infection mechanisms though, they are missing crucial components: immune cells and endothelial cells. This study aims to generate organoids with these components. We established vascular immune organoids from human pluripotent stem cells and examined the effect of SARS-CoV-2 infection. We demonstrated that infections activated inflammatory macrophages. Notably, the upregulation of interferon signaling supports macrophages role in cytokine release syndrome. We propose vascular immune organoids are a useful platform to model and discover factors that ameliorate SARS-CoV-2-mediated cytokine release syndrome.

immunology↗

bioRxiv2023

Sterol 3-beta-Glucosyltransferase TRANSPARENT TESTA15 Controls Seed Development and Flavanol Accumulation through its Role in Vacuole Biogenesis and Maintenance in Arabidopsis

The Arabidopsis sterol 3-beta-glucosyltransferase UGT80B1/TRANSPARENT TESTA15 (TT15) catalyzes sterol glucoside biosynthesis. Its loss of function causes reduced seed size, defective flavanol, polysaccharide and lipid polyester deposition at the seed coat and reduced seed dormancy. How TT15 controls seed development and physiology is unknown. Here we show that tt15 mutants exhibit seed lethality with incomplete penetrance and maternal determinism that is correlated with endosperm cellularization defects, together with an increased sensitivity of seed germination to exogenous abscisic acid and paclobutrazol. We also reveal that flavanol deposition in the vacuole during tt15 seed development triggers premature endothelium cell death. An autoimmune-like syndrome characterized by callose and H2O2 accumulation was detected in endothelium at the seed abaxial pole. Similar phenotypes were observed with tt9/gfs9, a mutant defective in endomembrane trafficking and homotypic vacuole fusion. Double mutant analysis showed that tt9 partially rescued tt15 endothelium phenotypes. Consistent with seed mutant phenotypes, TT15 promoter activity was detected in endothelium and endosperm and TT15 protein was located mainly at the vacuolar membrane (tonoplast). Using fluorescence recovery after photobleaching, we demonstrated that tonoplast fluidity was increased in tt15 roots. Altogether our data suggest that TT15 regulates seed development and flavanol accumulation by modulating vacuole biogenesis and maintenance.

plant biology↗

bioRxiv2022

Modular Pooled Discovery of Synthetic Knockin Sequences to Program Durable Cell Therapies

Chronic stimulation can cause T cell dysfunction and limit efficacy of cellular immunotherapies. CRISPR screens have nominated gene targets for engineered T cells, but improved methods are required to compare large numbers of synthetic knockin sequences to reprogram cell functions. Here, we developed Modular Pooled Knockin Screening (ModPoKI), an adaptable platform for modular construction of DNA knockin libraries using barcoded multicistronic adaptors. We built two ModPoKI libraries of 100 transcription factors (TFs) and 129 natural and synthetic surface receptors. Over 20 ModPoKI screens across human TCR and CAR T cells in diverse conditions identified a transcription factor AP4 (TFAP4) construct to enhance long-term T cell fitness and anti-cancer function in vitro and in vivo. ModPoKIs modularity allowed us to generate a [~]10,000-member library of TF combinations. Non-viral knockin of a combined BATF-TFAP4 polycistronic construct further enhanced function in vivo. ModPoKI facilitates discovery of complex gene constructs to program cellular functions. HighlightsO_LIModular pooled knockins of hundreds of TF and surface receptor constructs combined with different antigen receptors C_LIO_LIChronic stimulation screens discover programs to improve T cell persistence C_LIO_LICombinatorial knockin screens with [~]10,000 transcription factor combinations C_LIO_LIBATF-TFAP4 dual knockin construct improves CAR T cell function in vitro and in vivo C_LI

immunology↗

bioRxiv2021

Protein Vaccine Induces a Durable, More Broadly Neutralizing Antibody Response in Macaques than Natural Infection with SARS-CoV-2 P.1

FDA-approved and Emergency Use Authorized (EUA) vaccines using new mRNA and viral-vector technology are highly effective in preventing moderate to severe disease, however, information on their long-term efficacy and protective breadth against SARS-CoV-2 Variants of Concern (VOCs) is currently scarce. Here we describe the durability and broad-spectrum VOC immunity of a prefusion-stabilized spike (S) protein adjuvanted with liquid or lyophilized CoVaccine HT in cynomolgus macaques. This recombinant subunit vaccine is highly immunogenic and induces robust spike-specific and broadly neutralizing antibody responses effective against circulating VOCs (B.1.351 [Beta], P.1 [Gamma], B.1.617 [Delta]) for at least 3 months after the final boost. Protective efficacy and post-exposure immunity were evaluated using a heterologous P.1 challenge nearly 3 months after the last immunization. Our results indicate that while immunization with both high and low S doses shorten and reduce viral loads in the upper and lower respiratory tract, a higher antigen dose is required to provide durable protection against disease as vaccine immunity wanes. Histologically, P.1 infection causes similar COVID-19-like lung pathology as seen with early pandemic isolates. Post-challenge IgG concentrations were restored to peak immunity levels and vaccine-matched and cross-variant neutralizing antibodies were significantly elevated in immunized macaques indicating an efficient anamnestic response. Only low levels of P.1-specific neutralizing antibodies with limited breadth were observed in control (non-vaccinated but challenged) macaques suggesting that natural infection may not prevent reinfection by other VOCs. Overall, these results demonstrate that a properly dosed and adjuvanted recombinant subunit vaccine can provide long-lasting and protective immunity against circulating VOCs. One Sentence SummaryA recombinant subunit protein formulated with CoVaccine HT adjuvant induces superior immunity than natural infection and reduces viral load while protecting cynomolgus macaques from COVID-19-like disease caused by late SARS-CoV-2 P.1 (Gamma) challenge.

immunology↗

bioRxiv2021

Recombinant protein subunit SARS-CoV-2 vaccines formulated with CoVaccine HT adjuvant induce broad, Th1 biased, humoral and cellular immune responses in mice

The speed at which several COVID-19 vaccines went from conception to receiving FDA and EMA approval for emergency use is an achievement unrivaled in the history of vaccine development. Mass vaccination efforts using the highly effective vaccines are currently underway to generate sufficient herd immunity and reduce transmission of the SARS-CoV-2 virus. Despite the most advanced vaccine technology, global recipient coverage, especially in resource-poor areas remains a challenge as genetic drift in naive population pockets threatens overall vaccine efficacy. In this study, we described the production of insect-cell expressed SARS-CoV-2 spike protein ectodomain and examined its immunogenicity in mice. We demonstrated that, when formulated with CoVaccine HTadjuvant, an oil-in-water nanoemulsion compatible with lyophilization, our vaccine candidates elicit a broad-spectrum IgG response, high neutralizing antibody titers, and a robust, antigen-specific IFN-{gamma} secreting response from immune splenocytes in outbred mice. Our findings lay the foundation for the development of a dry-thermostabilized vaccine that is deployable without refrigeration.

immunology↗