Biology subjects

Moeller, R.

Publications and source records attributed to Moeller, R..

8 recordsLinked to original sources

bioRxiv2025

The biofilm matrix protects Bacillus subtilis against hydrogen peroxide

Biofilms formed by Bacillus subtilis confer protection against environmental stressors through extracellular polysaccharides (EPS) and sporulation. This study investigates the roles of these biofilm components in resistance to hydrogen peroxide, a common reactive oxygen species source and disinfectant. Using wild-type and mutant strains deficient in EPS or sporulation, biofilm colonies were cultivated at various maturation stages and exposed to hydrogen peroxide. EPS-deficient biofilms exhibited reduced resilience, particularly in early stages, highlighting the structural and protective importance of the matrix. Mature biofilms demonstrated additional protective mechanisms, potentially involving TasA protein fibers. In contrast, sporulation showed limited contribution to hydrogen peroxide resistance, as survival was primarily matrix-dependent. These findings underscore the necessity of targeting EPS and other matrix components in anti-biofilm strategies, suggesting that hydrogen peroxide-based disinfection could be enhanced by combining it with complementary sporicidal treatments. This study advances our understanding of biofilm resilience, contributing to the development of more effective sterilization protocols.

microbiology↗

bioRxiv2024

FLASH Bragg-peak irradiation with a therapeutic carbon ion beam: first in vivo results

Background and purposeIn recent years, ultra-high dose rate (UHDR) irradiation has emerged as a promising innovative approach to cancer treatment. Characteristic feature of this regimen, commonly referred to as FLASH effect, demonstrated primarily for electrons, photons or protons, is the improved normal tissue sparing, while the tumor control is similar to the one of the conventional dose-rate (CDR) treatments. The FLASH mechanism is, however, unknown. One major question is whether this effect is maintained when using densely ionizing (high-LET) heavy nuclei. Materials and MethodsHere we report the effects of 20 Gy UHDR heavy ion irradiation in clinically relevant conditions, i.e., at high-LET in the spread-out Bragg peak (SOBP) of a 12C beam using an osteosarcoma mouse model. ResultsWe show that UHDR irradiation was less toxic in the normal tissue compared to CDR while maintaining tumor control. The immune activation was also comparable in UHDR and CDR groups. We observed that the gut microbiome was altered in mice injected with the tumor compared to healthy animals, but both UHDR and CDR exposures steered the metagenome toward a balanced state. ConclusionsThe results show that the FLASH effect is safe and effective in heavy ion therapy and provide an important benchmark for the current mechanistic FLASH models. Highlights- FLASH irradiation with SOBP carbon ions spares normal tissue in mouse - Tumor control, immune response, and gut microbioma changes are induced at the same extent both at conventional and ultra-high dose rate - FLASH carbon ion irradiation is a safe and effective alternative to conventional radiotherapy.

cancer biology↗

bioRxiv2022

Enhanced assembly of bacteriophage T7 produced in cell-free reactions under simulated microgravity

On-demand biomanufacturing has the potential to improve healthcare and self-sufficiency during space missions. Cell-free transcription and translation reactions combined with DNA blueprints can produce promising therapeutics like bacteriophages and virus-like particles. However, how space conditions affect the synthesis and self-assembly of such complex multi-protein structures is unknown. Here, we characterize the cell-free production of infectious bacteriophage T7 virions under simulated microgravity. Rotation in a 2D-clinostat increased the number of infectious particles compared to static controls. Quantitative analyses by mass spectrometry, immuno-dot-blot and real-time PCR showed no significant differences in protein and DNA contents, suggesting enhanced self-assembly of T7 phages in simulated microgravity. While the effects of genuine space conditions on the cell-free synthesis and assembly of bacteriophages remain to be investigated, our findings support the vision of a cell-free synthesis-enabled "astropharmacy".

synthetic biology↗

bioRxiv2022

Innate immune response to SARS-1 CoV-2 infection contributes to neuronal damage in human iPSC-derived peripheral neurons

Severe acute respiratory coronavirus 2 (SARS-CoV-2) infection causes neurological disease in some patients suggesting that infection can affect both the peripheral and central nervous system (PNS and CNS, respectively). It is not clear whether the outcome of SARS-CoV-2 infection of PNS and CNS neurons is similar, and which are the key factors that cause neurological disease: SARS-CoV-2 infection or the subsequent immune response. Here, we addressed these questions by infecting human induced-pluripotent stem cell-derived CNS and PNS neurons with the {beta} strain of SARS-CoV-2. Our results show that SARS-CoV-2 infects PNS neurons more efficiently than CNS neurons, despite lower expression levels of angiotensin converting enzyme 2. Infected PNS neurons produced interferon {lambda}1, several interferon stimulated genes and proinflammatory cytokines. They also displayed neurodegenerative-like alterations, as indicated by increased levels of sterile alpha and Toll/interleukin receptor motif-containing protein 1, amyloid precursor protein and -synuclein and lower levels of nicotinamide mononucleotide adenylyltransferase 2 and {beta}-III-tubulin. Interestingly, blockade of the Janus kinase and signal transducer and activator of transcription pathway by Ruxolitinib did not increase SARS-CoV-2 infection, but reduced neurodegeneration, suggesting that an exacerbated neuronal innate immune response contributes to pathogenesis in the PNS.

microbiology↗

bioRxiv2020

Common genetic variation in humans impacts in vitro susceptibility to SARS-CoV-2 infection

The host response to SARS-CoV-2, the etiologic agent of the COVID-19 pandemic, demonstrates significant inter-individual variability. In addition to showing more disease in males, the elderly, and individuals with underlying co-morbidities, SARS-CoV-2 can seemingly render healthy individuals with profound clinical complications. We hypothesize that, in addition to viral load and host antibody repertoire, host genetic variants also impact vulnerability to infection. Here we apply human induced pluripotent stem cell (hiPSC)-based models and CRISPR-engineering to explore the host genetics of SARS-CoV-2. We demonstrate that a single nucleotide polymorphism (rs4702), common in the population at large, and located in the 3UTR of the protease FURIN, impacts alveolar and neuron infection by SARS-CoV-2 in vitro. Thus, we provide a proof-of-principle finding that common genetic variation can impact viral infection, and thus contribute to clinical heterogeneity in SARS-CoV-2. Ongoing genetic studies will help to better identify high-risk individuals, predict clinical complications, and facilitate the discovery of drugs that might treat disease.

cell biology↗

bioRxiv2020

Modulating the transcriptional landscape of SARS-CoV-2 as an effective method for developing antiviral compounds

To interfere with the biology of SARS-CoV-2, the virus responsible for the COVID-19 pandemic, we focused on restoring the transcriptional response induced by infection. Utilizing expression patterns of SARS-CoV-2-infected cells, we identified a region in gene expression space that was unique to virus infection and inversely proportional to the transcriptional footprint of known compounds characterized in the Library of Integrated Network-based Cellular Signatures. Here we demonstrate the successful identification of compounds that display efficacy in blocking SARS-CoV-2 replication based on their ability to counteract the virus-induced transcriptional landscape. These compounds were found to potently reduce viral load despite having no impact on viral entry or modulation of the host antiviral response in the absence of virus. RNA-Seq profiling implicated the induction of the cholesterol biosynthesis pathway as the underlying mechanism of inhibition and suggested that targeting this aspect of host biology may significantly reduce SARS-CoV-2 viral load.

microbiology↗

bioRxiv2020

SARS-CoV-2 launches a unique transcriptional signature from in vitro, ex vivo, and in vivo systems

One of the greatest threats to humanity is the emergence of a pandemic virus. Among those with the greatest potential for such an event include influenza viruses and coronaviruses. In the last century alone, we have observed four major influenza A virus pandemics as well as the emergence of three highly pathogenic coronaviruses including SARS-CoV-2, the causative agent of the ongoing COVID-19 pandemic. As no effective antiviral treatments or vaccines are presently available against SARS-CoV-2, it is important to understand the host response to this virus as this may guide the efforts in development towards novel therapeutics. Here, we offer the first in-depth characterization of the host transcriptional response to SARS-CoV-2 and other respiratory infections through in vitro, ex vivo, and in vivo model systems. Our data demonstrate the each virus elicits both core antiviral components as well as unique transcriptional footprints. Compared to the response to influenza A virus and respiratory syncytial virus, SARS-CoV-2 elicits a muted response that lacks robust induction of a subset of cytokines including the Type I and Type III interferons as well as a numerous chemokines. Taken together, these data suggest that the unique transcriptional signature of this virus may be responsible for the development of COVID-19.

microbiology↗

bioRxiv2020

Engineering an RNA-based tissue-specific platform for genetic editing through use of a miRNA-enabled Cas12a

The capacity to edit genomes using CRISPR-Cas systems holds immense potential for countless genetic-based diseases. However, one significant impediment preventing broad therapeutic utilization is in vivo delivery. While genetic editing at a single cell level in vitro can be achieved with high efficiency, the capacity to utilize these same biologic tools in a desired tissue in vivo remains challenging. Non-integrating RNA virus-based vectors constitute efficient platforms for transgene expression and surpass several barriers to in vivo delivery. However, the broad tissue tropism of viral vectors raises the concern for off-target effects. Moreover, prolonged expression of the Cas proteins, regardless of delivery method, can accumulate aberrant RNAs leading to unwanted immunological responses. In an effort to circumvent these shortcomings, here we describe a versatile RNA virus-based technology that can achieve cell-specific activity and self-inactivation by combining host microRNA (miRNA) biology with the CRISPR-Cas12a RNA-guided nuclease. Exploiting the RNase activity of Cas12a, we generated a vector that self-inactivates upon delivery of Cas12a and an accompanying CRISPR RNA (crRNA). Furthermore, we show that maturation of the crRNA can be made dependent on cell-specific miRNAs, which confers cell-specificity. We demonstrate that this genetic editing circuit delivers diminished yet sufficient levels of Cas12a to achieve effective genome editing whilst inducing a minimal immunological response. It can also function in a cell-specific manner thereby facilitating in vivo editing and mitigating the risk of unwanted, off-target effects.

bioengineering↗