Biology subjects

Froehlich, T.

Publications and source records attributed to Froehlich, T..

12 recordsLinked to original sources

bioRxiv2026

A positively selected microRNA controls a reversible aging program in striated muscle

Aging is the primary risk factor for most chronic diseases and is characterized in striated muscle by progressive functional decline, mitochondrial dysfunction, and chronic inflammation. The miR-128-1 locus resides within a positively selected haplotype on chromosome 2q21.3 associated with variation in grip strength, pulmonary function, and cardiometabolic traits in humans. Here, we show that antisense oligonucleotide-mediated inhibition of miR-128-3p restores muscle mass and function in aged mice, improves cardiac function while limiting adverse remodeling following myocardial infarction, and ameliorates skeletal and cardiac muscle pathology in mouse and pig models of Duchenne muscular dystrophy. Across these contexts, miR-128-3p inhibition induces a conserved transcriptional response characterized by activation of mitochondrial programs and suppression of inflammatory and fibrotic signaling, resembling the effects of established longevity interventions. These findings identify miR-128-3p as a regulator of a conserved aging-associated program and establish its inhibition as a strategy to restore tissue function across aging-related muscle pathologies.

molecular biology↗

bioRxiv2026

Microplastics Disrupt Predator-Induced Plasticity in Daphnia across Behavioral, Morphological and Molecular Levels

Microplastics (MP) are widespread in aquatic ecosystems and pose a threat to freshwater biodiversity. While numerous studies examine physiological effects on aquatic organisms, less is known about how MP alter chemically mediated interactions that regulate predator-prey dynamics. Predator-induced defenses in Daphnia depend on detecting kairomones and represent an important form of adaptive phenotypic plasticity. Whether MP interfere with these responses, and through which mechanisms, remains unclear. Here, we show that polystyrene MP impair predator-induced defenses across Daphnia species by disrupting predator-cue-mediated plasticity at the behavioral, morphological, and molecular levels. In D. longicephala, chronic exposure to PS fragments weakened Notonecta-induced morphological defenses, whereas additive-containing PS fragments nearly suppressed defense formation and reduced body size. Consistent with these phenotypic effects, proteomic analyses revealed alterations in pathways related to molting and chitin metabolism, linking MP exposure to impaired defense formation. In D. magna, PS particles attenuated fish kairomone-induced diel vertical migration, with stronger effects for larger particles, consistent with reduced effective availability or perception of predator cues. Natural limestone particles caused only minor effects, indicating particle-specific rather than general particle-driven responses. Our findings demonstrate that MP can disrupt adaptive predator-prey interactions with potential cascading consequences for freshwater food webs.

zoology↗

bioRxiv2025

It is Not Always Crystal Clear: In-Pocket Analysis for Understanding Binding Site Microenvironment Properties

Structural biology enabled key advances in biochemistry, drug discovery, and AI-driven three-dimensional structure modelling. Despite its importance, reliable and general computational tools for chemical validation of structural models remain limited, especially when small-molecule ligands are involved. This challenge is exacerbated when experimental resolution is insufficient to define interaction chemistry, leaving critical interpretations ambiguous. We introduce In-Pocket, a quantum mechanical optimisation method biased by experimental data that evaluates the chemical nature of protein-ligand binding interfaces. In-Pocket improves model quality, corrects chemically inconsistent structures, and identifies the energetically most favourable ligand-conformers within biomacromolecular complexes. The approach is generally applicable to a wide range of systems, including those containing transition metals. Benchmarking demonstrates that In-Pocket enhances the reliability of legacy and newly solved structures. With automated, user-friendly routine chemical validation, In-Pocket offers unique opportunities to improve the integrity of structural databases and impact diverse domains: from molecular biology to rational drug design and application of generative AI.

bioinformatics↗

bioRxiv2024

A dual role in virion attachment and entry makes the human cytomegalovirus gHgLgO trimer the central player in virion infectivity

Glycoproteins in the viral envelope of human cytomegalovirus (HCMV) orchestrate virion tethering, receptor recognition and fusion with cellular membranes. The glycoprotein gB acts as fusion protein. The gHgL complexes gHgLgO and gHgLpUL(128,130,131A) define the HCMV cell tropism. Studies with HCMV lacking gO had indicated that gO, independently of binding to its cellular receptor PDGFR, plays an important second role in infection. Here, we identified a gO mutation which abolished virus particle infectivity by preventing the interaction of gHgLgO with host cell heparan sulfate proteoglycans (HSPGs). We could not only show that gHgLgO - HSPG interactions are a genuine second role of gHgLgO, but also that gHgLgO is the main player in determining the infectivity of HCMV virus particles. This challenges long-accepted textbook knowledge on the role of gB and gMgN complexes in virion tethering. Additionally, it adds the gHgLgO complex to the antigens of interest for future HCMV vaccines or treatments.

microbiology↗

bioRxiv2024

Quantum Chemistry in a Pocket: A Multifaceted Tool to Link Structure and Activity

We introduce In-Pocket Analysis, a simple and efficient protein-ligand complex structure optimization algorithm. It provides structural biology and structure-based drug discovery with a much-needed tool for data curation and quantification analysis. In-pocket analysis removes unphysical tension from experimental structures, yielding high-quality atomic models. This includes deformed bonds, structural clashes, proton refinement, and solvent envelope. The algorithm is compatible with quantum methods or force fields, delivering precise calculations of binding energies and QSAR. Its applications include refinement of experimental structures, calculation of inter- and intramolecular energetics, scoring of docked poses, scaffold decoration/hopping, or building of explainable QSAR. For validation and benchmarking we used high-resolution crystal structures of the N-terminal domain of PEX14 with small-molecule inhibitors. PEX14 is a target candidate against Trypanosomiasis and Leishmaniasis. The application of our algorithm allowed for an explanation of unexpected binding poses, rationalization of binding energies, and affinities as well as precise quantification of solvent-mediated interactions. TABLE OF CONTENTS O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=160 SRC="FIGDIR/small/590615v1_ufig1.gif" ALT="Figure 1"> View larger version (60K): org.highwire.dtl.DTLVardef@11f4173org.highwire.dtl.DTLVardef@1020358org.highwire.dtl.DTLVardef@12986ecorg.highwire.dtl.DTLVardef@1590617_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioinformatics↗

bioRxiv2023

Nanobodies as novel tools to monitor the mitochondrial fission factor Drp1

In cells, mitochondria undergo constant fusion and fission. An essential factor for fission is the mammalian dynamin-related protein 1 (Drp1). Dysregulation of Drp1 has been linked to neurodegenerative diseases including Parkinsons as well as cardiovascular diseases and cancer. Here, we developed nanobodies (Nbs) for proteomics, advanced microscopy and live cell imaging of Drp1. To specifically enrich endogenous Drp1 with interacting proteins for proteomics, we functionalized high-affinity Nbs as capture matrices. Furthermore, we detected Drp1 by bivalent Nbs combined with site-directed fluorophore labelling in super-resolution STORM microscopy. For real-time imaging of Drp1, we intracellularly expressed fluorescently labelled Nbs, so-called chromobodies (Cbs). To improve the signal-to-noise ratio, we further converted Cbs into a "turnover-accelerated" format. With these imaging probes, we visualized the dynamics of endogenous Drp1 upon compound-induced mitochondrial fission in living cells. Considering the wide range of research applications, the presented Nb toolset will open up new possibilities for advanced functional studies of Drp1 in disease-relevant models.

cell biology↗

bioRxiv2023

Increased pulmonary monocyte infiltration and attenuated phagocytosis defines perinatal dysfunction of innate immunity in Cystic Fibrosis

In Cystic Fibrosis (CF) patients, cycles of infection and inflammation lead to fatal lung damage. While diminished mucus clearance is restored by highly effective CFTR modulator therapy, inflammation and infection persist in treated patients, suggesting alternative mechanisms may contribute to impaired immunity in CF. Here, we made use of a CF pig model to investigate the innate immune system at birth, before the onset of infection. We observed a substantial change in the composition of tissue resident immune cells towards emergency myelopoiesis, accompanied by increased infiltration of monocytes into CF lungs. A more immature status in the transcriptome profile of classical monocytes in CF pigs and preschool children with CF correlated with reduced phagocytic capacity, confirming a congenital and translationally conserved aberration of the immune system in CF. The lack of CFTR expression in circulating monocytes indicates an indirect etiology of these effects and suggests that additional immunological treatments are necessary for CF patients. One Sentence SummaryIncreased infiltration of lung tissue by monomyeloid cells and their impaired phagocytic potential cause dysfunctional imprinting of mucosal immunity in Cystic Fibrosis airways at birth and suggest early and specific treatment of the innate immune system in patients.

immunology↗

bioRxiv2023

Can Quantum Chemistry Improve the understanding of Protein-Ligand Interactions? Implications for Structure Based Drug Discovery

We introduce an Energy Decomposition Analysis suitable for understanding the nature of non-covalent binding in large chemical systems, like those of drug-protein complexes. The method is atom specific, thus allowing rationalization of the role that each atom or functional group plays for the interaction. Visual representations are constructed in the form of interaction maps, depicting the different contributions for electrostatics, polarization, dispersion (lipophilicity), etc. This marks the departure from atomistic models towards electronic interaction ones, that better correlate with experimental data. The maps provide a quick access to the driving forces behind the formation of intermolecular complexes, and the key contributors for each interaction. This allows constructing quantum mechanical models of binding. The presented method is validated against experimental binding data for the difficult to target protein-protein interface for PEX14-PEX5 and its inhibitors.

bioinformatics↗

bioRxiv2021

A nanobody-based toolset to monitor and modify the mitochondrial GTPase Miro1

The mitochondrial outer membrane (MOM)-anchored GTPase Miro1, is a central player in mitochondrial transport and homeostasis. The dysregulation of Miro1 in amyotrophic lateral sclerosis (ALS) and Parkinsons disease (PD) suggests that Miro1 may be a potential biomarker or drug target in neuronal disorders. However, the molecular functionality of Miro1 under (patho-) physiological conditions is poorly known. For a more comprehensive understanding of the molecular functions of Miro1, we have developed Miro1-specific nanobodies (Nbs) as novel research tools. We identified seven Nbs that bind either the N- or C-terminal GTPase domain of Miro1 and demonstrate their application as research tools for proteomic and imaging approaches. To visualize the dynamics of Miro1 in real time, we selected intracellularly functional Nbs, which we reformatted into chromobodies (Cbs) for time- lapse imaging of Miro1. By genetic fusion to an Fbox domain, these Nbs were further converted into Miro1-specific degrons and applied for targeted degradation of Miro1 in live cells. In summary, this study presents a collection of novel Nbs that serve as a toolkit for advanced biochemical and intracellular studies and modulations of Miro1, thereby contributing to the understanding of the functional role of Miro1 in disease-derived model systems.

cell biology↗

bioRxiv2021

Recognition and deubiquitination of free 40S for translational reset by Otu2

In actively translating 80S ribosomes the ribosomal protein eS7 of the 40S subunit is monoubiquitinated by the E3 ligase Not41,2 and deubiquitinated by the deubiquitination enzyme Otu2 upon ribosomal subunit recycling3. Despite its importance for general efficiency of translation the exact role and structural basis for this specific translational reset are only poorly understood. Here we present biochemical and structural data showing that Otu2 can engage the recycled 40S subunit together with the recycling factors ABCE1 and Tma64 immediately after 60S dissociation for mRNA recycling, and that it dissociates before 48S initiation complex formation. A combined structural analysis of Otu2 and Otu2-40S complexes by X-ray crystallography, AlphaFold2 prediction4 and cryo-EM revealed how Otu2 can specifically be recruited to the 40S, but not to the 80S ribosome, for removal of the eS7-bound ubiquitin moiety. Here, interactions of the largely helical N-terminal domain of Otu2 to sites that are masked and therefore inaccessible in the 80S ribosome are of crucial importance. Collectively, we provide the structural basis for the Otu2 driven deubiquitination step providing a first mechanistic understanding of this translational reset step during ribosome recycling/(re)initiation.

molecular biology↗

bioRxiv2021

A scalable, clinically severe pig model for Duchenne muscular dystrophy

Large animal models for Duchenne muscular dystrophy (DMD) are crucial for preclinical evaluation of novel diagnostic procedures and treatment strategies. Pigs cloned from male cells lacking DMD exon 52 (DMD{Delta}52) resemble molecular, clinical and pathological hallmarks of DMD, but cannot be propagated by breeding due to death before sexual maturity. Therefore, female DMD+/- carriers were generated. A single founder animal had 11 litters with 29 DMDY/-, 34 DMD+/- as well as 36 male and 29 female wild-type (WT) offspring. Breeding with F1 and F2 DMD+/- carriers resulted in additional 114 DMDY/- piglets. The majority of them survived for 3-4 months, providing large cohorts for experimental studies. Pathological investigations and proteome studies of skeletal muscles and myocardium confirmed the resemblance of human disease mechanisms. Importantly, DMDY/- pigs reveal progressive fibrosis of myocardium and increased expression of connexin-43, associated with significantly reduced left ventricular fractional shortening and ejection fraction already at age 3 months. Furthermore, behavioral tests provided evidence for impaired cognitive ability of DMDY/- pigs. Our breeding cohort of DMD{Delta}52 pigs and standardized tissue repositories from DMDY/- pigs, DMD+/- carriers, and WT littermate controls provide important resources for studying DMD disease mechanisms and for testing novel diagnostic procedures and treatment strategies.

pathology↗

bioRxiv2020

Structural basis for translational shutdown and immune evasion by the Nsp1 protein of SARS-CoV-2

SARS-CoV-2 is the causative agent of the current COVID-19 pandemic. A major virulence factor of SARS-CoVs is the nonstructural protein 1 (Nsp1) which suppresses host gene expression by ribosome association via an unknown mechanism. Here, we show that Nsp1 from SARS-CoV-2 binds to 40S and 80S ribosomes, resulting in shutdown of capped mRNA translation both in vitro and in cells. Structural analysis by cryo-electron microscopy (cryo-EM) of in vitro reconstituted Nsp1-40S and of native human Nsp1-ribosome complexes revealed that the Nsp1 C-terminus binds to and obstructs the mRNA entry tunnel. Thereby, Nsp1 effectively blocks RIG-I-dependent innate immune responses that would otherwise facilitate clearance of the infection. Thus, the structural characterization of the inhibitory mechanism of Nsp1 may aid structure-based drug design against SARS-CoV-2.

molecular biology↗