Biology subjects

Klose, A.

Publications and source records attributed to Klose, A..

5 recordsLinked to original sources

bioRxiv2026

DNA origami uptake in Y-79 retinoblastoma cells driven by oligolysine coating

DNA origami nanoparticles (DONs) are attractive nanocarriers of controllable size, shape and addressability that have potential for treating eye diseases by overcoming ocular barriers. However, suboptimal physiological stability and poor cell uptake due to the negative charge may limit their use. Previous reports show that electrostatic complexation of DONs with cationic PEG-oligolysine block-copolymers like PEG5K-K10 can improve structural integrity and promote cell internalization. Here, we investigated a dual approach of PEG5K-K10 coatings and PL3 targeting peptides to improve uptake of 24-helix bundle (24HB) DONs into Y-79 retinoblastoma cells. Uptake studies revealed that PEG5K-K10 was essential for DON uptake in Y-79 cells, as uptake only occurred upon exceeding a distinct PEG5K-K10 amount. Longer exposure times or increased polymer amounts improved cell association. However, no beneficial effect of PL3 was observed. While free PEG5K-K10 reduced cell viability at higher concentrations (IC50 36.8 {micro}M), coated DONs were well-tolerated. Furthermore, single particle tracking in ex vivo porcine eyes revealed comparable vitreal mobility for uncoated and coated 24HB, with a slight decrease at higher coating amounts. Our findings highlight that PEG5K-K10 can enhance ocular cell uptake without limiting nanoparticle diffusivity in the vitreous, and support further optimization of DONs for ocular drug delivery.

biochemistry↗

bioRxiv2025

A Mouse Model of SARS-CoV-2-Driven Acute Maladaptive Responses and Chronic Systemic Diseases

Our understanding of SARS-CoV-2 acute and post-acute pathogenesis is hindered by the lack of adequate small animal models. We present RAB/6N, a mouse model prone to severe disease after exposure to SARS-CoV-2 clinical isolates, with lethal cases showing no widespread brain infection typical of the widely used K18-hACE2 mouse model. Lung viral replication in RAB/6N mice remains steady for several days before a decline in viral titers. Delayed initiation of infection clearance is marked by increased lung T-cell extravasation and type-2 immune responses, leading to maladaptive lung consolidation. While systemic antiviral cytokine responses only correlate with SARS-CoV-2 brain infection in K18-hACE2 mice, they are concomitant with pulmonary immune dynamics in infected RAB/6N mice. Convalescent RAB/6N mice display systemic inflammation and decreased antibody titers against SARS-CoV-2 spike RBD, persistent viral RNA and prolonged lymphoid infiltration in the lungs. These animals also exhibit signatures of multi-organ dysfunction, cognitive impairment, cardiac inflammation, hyper- immunoglobulin production, and various autoimmune disorders, illuminating the molecular correlates of various pathologies associated with post-acute sequelae of COVID-19 (PASC). RAB/6N mice pave the way for dissecting the molecular drivers underlying SARS-CoV-2-induced acute maladaptive responses and subsequent post-acute systemic diseases. This preclinical platform also opens opportunities for the exploration of therapeutic interventions against systemic PASC and for anticipating the emergence of PASC-associated comorbidities. One-sentence summaryWe generated a hACE2-transgenic mouse model that develops maladaptive lung immune responses upon acute SARS-CoV-2 infection, leading to fatal outcomes or post-acute systemic disease syndromes in convalescent animals.

microbiology↗

bioRxiv2025

Biomass-derived Lignin Nanoparticles for the Sustained Delivery of Vascular Endothelial Growth Factor-C

Vascular Endothelial Growth Factor C (VEGFC) is a promising biological drug, as preclinical studies have shown its potential in treating a variety of conditions, including myocardial infarction and neurodegenerative diseases. For lymphedema, a disease that currently can only be treated symptomatically, adenoviral VEGFC gene therapy has been evaluated up to phase II studies. However, the AdVEGFC is rapidly inactivated by the immune system, and alternative delivery methods might yield better results. Thus, we wanted to investigate the synthesis, characterization, and stability of lignin nanoparticles (LNPs) as carriers for VEGFC. As biomass-derived lignin nanoparticles provide a sustainable, cost-effective, and tunable platform for drug delivery, with the potential to enhance drug stability and release, lignin was extracted from wood biomass derived from grape shoots using the organosolv method and subsequently synthesized into nanoparticles. The resulting lignin nanoparticles (LNPs), with an average size of 142{+/-}62 nm and a zeta potential of -40{+/-}8 mV, were characterized through comprehensive techniques, including spectroscopy and microscopy, to gain insights into their structural and morphological properties. Furthermore, the loading and release efficiency of VEGFC onto LNPs were evaluated, demonstrating effective loading and controlled release. Stability tests in plasma and cell proliferation/viability assessments using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay were conducted to assess biocompatibility and therapeutic potential. Our data shows that VEGFC is a relatively stable protein and that the primary advantage of nanoparticle-based delivery would be to delay release as opposed to protect VEGFC from degradation/inactivation. Graphical AbstractFlow chart of the generation and analysis of biomass-derived VEGFC-loaded lignin nanoparticles. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=109 SRC="FIGDIR/small/649697v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@1476841org.highwire.dtl.DTLVardef@10d861corg.highwire.dtl.DTLVardef@dfa209org.highwire.dtl.DTLVardef@72c81_HPS_FORMAT_FIGEXP M_FIG C_FIG

pharmacology and toxicology↗

bioRxiv2024

Fluorescence Anisotropy Analysis of the Interaction between Doxorubicin and DNA Origami Nanostructures

Owing to doxorubicins high DNA binding affinity, doxorubicin-loaded DNA origami nanostructures (DOX-DONs) are promising nanocarriers against cancer. However, understanding the interactions between doxorubicin (DOX) and DNA origami nanostructures (DONs) is important to ensure the quality of DOX-DONs. This interaction is often taken for granted and the influence of DOX loading conditions is poorly characterized. Exploiting the inherent fluorescence of DOX, steady-state and time-resolved fluorescence anisotropy spectroscopy techniques are used for characterizing non-destructively the binding between DOX and DONs, and the purity of formed complexes. The difference in fluorescence anisotropy between free DOX and DOX-DONs confirms the DOX-DON complex formation. Further, at loading ratios of DOX to DNA base pairs > 0.5, homo-Forster resonance energy transfer (homo-FRET) between closely packed DOX molecules is observed. Moreover, time-resolved anisotropy reveals DOX aggregation on DONs at high loading ratios > 1. For loading ratios > 0.1, spin-filtration to remove excess free DOX is efficient and necessary, though at loading ratios > 1 some DOX aggregates remain attached to the DONs. In summary, fluorescence anisotropy analysis provides more detailed information and insight into DOX-DONs compared to regularly used fluorescence intensity-based characterization methods, and these results can help designing more efficient and safer DNA intercalator-based nanocarriers.

biochemistry↗

bioRxiv2021

Macrophages govern antiviral responses in human lung tissues protected from SARS-CoV-2 infection

The majority of SARS-CoV-2 infections among healthy individuals result in asymptomatic to mild disease. However, the immunological mechanisms defining effective lung tissue protection from SARS-CoV-2 infection remain elusive. Unlike mice solely engrafted with human fetal lung xenograft (fLX), mice co-engrafted with fLX and a myeloid-enhanced human immune system (HNFL mice) are protected against SARS-CoV-2 infection, severe inflammation, and histopathology. Effective control of viral infection in HNFL mice associated with significant macrophage infiltration, and the induction of a potent macrophage-mediated interferon response. The pronounced upregulation of the USP18-ISG15 axis (a negative regulator of IFN responses), by macrophages was unique to HNFL mice and represented a prominent correlate of reduced inflammation and histopathology. Altogether, our work shed light on unique cellular and molecular correlates of lung tissue protection during SARS-CoV-2 infection, and underscores macrophage IFN responses as prime targets for developing immunotherapies against coronavirus respiratory diseases. HIGHLIGHTSO_LIMice engrafted with human fetal lung xenografts (fLX-mice) are highly susceptible to SARS-CoV-2. C_LIO_LICo-engraftment with a human myeloid-enriched immune system protected fLX-mice against infection. C_LIO_LITissue protection was defined by a potent and well-balanced antiviral response mediated by infiltrating macrophages. C_LIO_LIProtective IFN response was dominated by the upregulation of the USP18-ISG15 axis. C_LI

microbiology↗