Sonogenetics for Monitoring and Modulating Biomolecular Function by Ultrasound

Ultrasound technology, synergistically harnessed with genetic engineering and chemistry concepts, has started to open the gateway to the remarkable realm of sonogenetics-a pioneering paradigm for remotely orchestrating cellular functions at the molecular level. This fusion not only enables precisely targeted imaging and therapeutic interventions, but also advances our comprehension of mechanobiology to unparalleled depths. Sonogenetic tools harness mechanical force within small tissue volumes while preserving the integrity of the surrounding physiological environment, reaching depths of up to tens of centimeters with high spatiotemporal precision. These capabilities circumvent the inherent physical limitations of alternative in vivo control methods such as optogenetics and magnetogenetics. In this review, we first discuss mechanosensitive ion channels, the most commonly utilized sonogenetic mediators, in both mammalian and non-mammalian systems. Subsequently, we provide a comprehensive overview of state-of-the-art sonogenetic approaches that leverage thermal or mechanical features of ultrasonic waves. Additionally, we explore strategies centered around the design of mechanochemically reactive macromolecular systems. Furthermore, we delve into the realm of ultrasound imaging of biomolecular function, encompassing the utilization of gas vesicles and acoustic reporter genes. Finally, we shed light on limitations and challenges of sonogenetics and present a perspective on the future of this promising technology.

Phospholipid Membranes as Chemically and Functionally Tunable Materials

The sheet-like lipid bilayer is the fundamental structural component of all cell membranes. Its building blocks are phospholipids and cholesterol. Their amphiphilic structure spontaneously leads to the formation of a bilayer in aqueous environment. Lipids are not just structural elements. Individual lipid species, the lipid membrane structure, and lipid dynamics influence and regulate membrane protein function. An exciting field is emerging where the membrane-associated material properties of different bilayer systems are used in designing innovative solutions for widespread applications across various fields, such as the food industry, cosmetics, nano- and biomedicine, drug storage and delivery, biotechnology, nano- and biosensors, and computing. Here, the authors summarize what is known about how lipids determine the properties and functions of biological membranes and how this has been or can be translated into innovative applications. Based on recent progress in the understanding of membrane structure, dynamics, and physical properties, a perspective is provided on how membrane-controlled regulation of protein functions can extend current applications and even offer new applications.

Mechanochemical Activation of DNAzyme by Ultrasound

Controlling the activity of DNAzymes by external triggers is an important task. Here a temporal control over DNAzyme activity through a mechanochemical pathway with the help of ultrasound (US) is demonstrated. The deactivation of the DNAzyme is achieved by hybridization to a complementary strand generated through rolling circle amplification (RCA), an enzymatic polymerization process. Due to the high molar mass of the resulting polynucleic acids, shear force can be applied on the RCA strand through inertial cavitation induced by US. This exerts mechanical force and leads to the cleavage of the base pairing between RCA strand and DNAzyme, resulting in the recovery of DNAzyme activity. This is the first time that this release mechanism is applied for the activation of catalytic nucleic acids, and it has multiple advantages over other stimuli. US has higher penetration depth into tissues compared to light, and it offers a more specific stimulus than heat, which has also limited use in biological systems due to cell damage caused by hyperthermia. This approach is envisioned to improve the control over DNAzyme activity for the development of reliable and specific sensing applications.

Shape morphing of hydrogels by harnessing enzyme enabled mechanoresponse

Hydrogels have been designed to react to many different stimuli which find broad applications in tissue engineering and soft robotics. However, polymer networks bearing mechano-responsiveness, especially those displaying on-demand self-stiffening and self-softening behavior, are rarely reported. Here, we design a mechano-controlled biocatalytic system at the molecular level that is incorporated into hydrogels to regulate their mechanical properties at the material scale. The biocatalytic system consists of the protease thrombin and its inhibitor, hirudin, which are genetically engineered and covalently coupled to the hydrogel networks. The catalytic activity of thrombin is reversibly switched on by stretching of the hydrogels, which disrupts the noncovalent inhibitory interaction between both entities. Under cyclic tensile-loading, hydrogels exhibit self-stiffening or self-softening properties when substrates are present that can self-assemble to form new networks after being activated by thrombin or when cleavable peptide crosslinkers are constitutional components of the original network, respectively. Additionally, we demonstrate the programming of bilayer hydrogels to exhibit tailored shape-morphing behavior under mechanical stimulation. Our developed system provides proof of concept for mechanically controlled reversible biocatalytic processes, showcasing their potential for regulating hydrogels and proposing a biomacromolecular strategy for mechano-regulated soft functional materials.

First measurements of an imaging heavy ion beam probe at the ASDEX Upgrade tokamak

The imaging heavy ion beam probe (i-HIBP) diagnostic has been successfully commissioned at ASDEX Upgrade. The i-HIBP injects a primary neutral beam into the plasma, where it is ionized, leading to a fan of secondary (charged) beams. These are deflected by the magnetic field of the tokamak and collected by a scintillator detector, generating a strike-line light pattern that encodes information on the density, electrostatic potential, and magnetic field of the plasma edge. The first measurements have been made, demonstrating the proof-of-principle of this diagnostic technique. A primary beam of 85/87Rb has been used with energies ranging between 60 and 72 keV and extracted currents up to 1.5 mA. The first signals have been obtained in experiments covering a wide range of parameter spaces, with plasma currents (Ip) between 0.2 and 0.8 MA and on-axis toroidal magnetic field (Bt) between 1.9 and 2.7 T. Low densities appear to be critical for the performance of the diagnostic, as signals are typically observed only when the line integrated density is below 2.0-3.0 × 1019 m-2 in the central interferometer chord, depending on the plasma shape. The strike line moves as expected when Ip is ramped, indicating that current measurements are possible. Additionally, clear dynamics in the intensity of the strike line are often observed, which might be linked to changes in the edge profile structure. However, the signal-to-background ratio of the signals is hampered by stray light, and the image guide degradation is due to neutron irradiation. Finally, simulations have been carried out to investigate the sensitivity of the expected signals to plasma density and temperature. The results are in qualitative agreement with the experimental observations, suggesting that the diagnostic is almost insensitive to fluctuations in the temperature profile, while the signal level is highly determined by the density profile due to the beam attenuation.

Polymeric materials for ultrasound imaging and therapy

Ultrasound (US) is routinely used for diagnostic imaging and increasingly employed for therapeutic applications. Materials that act as cavitation nuclei can improve the resolution of US imaging, and facilitate therapeutic US procedures by promoting local drug delivery or allowing temporary biological barrier opening at moderate acoustic powers. Polymeric materials offer a high degree of control over physicochemical features concerning responsiveness to US, e.g. via tuning chain composition, length and rigidity. This level of control cannot be achieved by materials made of lipids or proteins. In this perspective, we present key engineered polymeric materials that respond to US, including microbubbles, gas-stabilizing nanocups, microcapsules and gas-releasing nanoparticles, and discuss their formulation aspects as well as their principles of US responsiveness. Focusing on microbubbles as the most common US-responsive polymeric materials, we further evaluate the available chemical toolbox to engineer polymer shell properties and enhance their performance in US imaging and US-mediated drug delivery. Additionally, we summarize emerging applications of polymeric microbubbles in molecular imaging, sonopermeation, and gas and drug delivery, based on refinement of MB shell properties. Altogether, this manuscript provides new perspectives on US-responsive polymeric designs, envisaging their current and future applications in US imaging and therapy.

Polymer Mechanochemistry in Microbubbles

Polymer mechanochemistry is a promising technology to convert mechanical energy into chemical functionality by breaking covalent and supramolecular bonds site-selectively. Yet, the mechanochemical reaction rates of covalent bonds in typically used ultrasonication setups lead to reasonable conversions only after comparably long sonication times. This can be accelerated by either increasing the reactivity of the mechanoresponsive moiety or by modifying the encompassing polymer topology. Here, a microbubble system with a tailored polymer shell consisting of an N2 gas core and a mechanoresponsive disulfide-containing polymer network is presented. It is found that the mechanochemical activation of the disulfides is greatly accelerated using these microbubbles compared to commensurate solid core particles or capsules filled with liquid. Aided by computational simulations, it is found that low shell thickness, low shell stiffness and crosslink density, and a size-dependent eigenfrequency close to the used ultrasound frequency maximize the mechanochemical yield over the course of the sonication process.

Sulfated Polyglycerol-Modified Hydrogels for Binding HSV-1 and RSV

Heparan sulfate (HS) is a highly sulfated polysaccharide on the surface of mammalian cells and in the extracellular matrix and has been found to be important for virus binding and infection. In this work, we designed synthetic hydrogels with viral binding and deactivation activities through the postfunctionalization of an HS-mimicking polyelectrolyte and alkyl chains. Three polyglycerol-based hydrogels were prepared as substrates and postfunctionalized by sulfated linear polyglycerol (lPGS) via thiol-ene click reaction. The viral binding properties were studied using herpes simplex virus type 1 (HSV-1) and respiratory syncytial virus (RSV). The effect of hydrogel types and molecular weight (Mw) of conjugated lPGS on viral binding properties was also assessed, and promising binding activities were observed in all lPGS-functionalized samples. Further coupling of 11 carbons long alkyl chains to the hydrogel revealed virucidal properties caused by destruction of the viral envelope, as shown by atomic force microscopy (AFM) imaging.

Oral cladribine treatment and idiosyncratic drug-induced liver injury in multiple sclerosis

Background

Oral cladribine (OC) is approved for the treatment of highly active relapsing multiple sclerosis. Postmarketing safety assessments have reported rare, but occasionally severe cases of liver injury in temporal association with OC, with pathophysiologic mechanisms still unknown. In the only detailed case report on this topic, idiosyncratic drug-induced liver injury (iDILI) during OC treatment was well characterised for the first time, but occurred in the context of prior high-dose steroid exposure. Although high-dose steroids are known to induce iDILI in patients with multiple sclerosis with a delay of up to 12 weeks, OC was assumed to be the culprit agent for observed liver injury and the role of steroid exposure was not further investigated.

Case

Herein, we describe a case of a 35-year-old women treated with high-dose oral prednisolone during the first treatment cycle OC and subsequently developed iDILI. A causality assessment of the role of prednisolone and OC was performed using the updated Roussel Uclaf Causality Assessment Method which also included a negative re-exposure test for OC during the second OC treatment cycle 1 year later.

Conclusion

Our observations suggest that prednisolone or interactions between prednisolone and OC are more likely to foster development of iDILI rather than OC treatment itself.

Biochemical and structural insight into the chemical resistance and cofactor specificity of the formate dehydrogenase from Starkeya novella

Formate dehydrogenases (Fdhs) mediate the oxidation of formate to carbon dioxide and concomitant reduction of nicotinamide adenine dinucleotide (NAD+ ). The low cost of the substrate formate and importance of the product NADH as a cellular source of reducing power make this reaction attractive for biotechnological applications. However, the majority of Fdhs are sensitive to inactivation by thiol-modifying reagents. In this study, we report a chemically resistant Fdh (FdhSNO ) from the soil bacterium Starkeya novella strictly specific for NAD+ . We present its recombinant overproduction, purification and biochemical characterization. The mechanistic basis of chemical resistance was found to be a valine in position 255 (rather than a cysteine as in other Fdhs) preventing the inactivation by thiol-modifying compounds. To further improve the usefulness of FdhSNO as for generating reducing power, we rationally engineered the protein to reduce the coenzyme nicotinamide adenine dinucleotide phosphate (NADP+ ) with better catalytic efficiency than NAD+ . The single mutation D221Q enabled the reduction of NADP+ with a catalytic efficiency kCAT /KM of 0.4 s-1 ·mm-1 at 200 mm formate, while a quadruple mutant (A198G/D221Q/H379K/S380V) resulted in a fivefold increase in catalytic efficiency for NADP+ compared with the single mutant. We determined the cofactor-bound structure of the quadruple mutant to gain mechanistic evidence behind the improved specificity for NADP+ . Our efforts to unravel the key residues for the chemical resistance and cofactor specificity of FdhSNO may lead to wider use of this enzymatic group in a more sustainable (bio)manufacture of value-added chemicals, as for instance the biosynthesis of chiral compounds.

Recombinant supercharged polypeptides for safe and efficient heparin neutralization

Heparin is a widely used anticoagulant agent in the clinic. After application, its anticoagulant effect must be reversed to prevent potential side effects. Protamine sulfate (PS) is the only clinically licensed antidote that has been used for this purpose in the last 80 years, which, however, provokes severe adverse effects, such as systemic hypotension and even death. Herein, we demonstrate the potential of supercharged polypeptides as a promising alternative for protamine sulfate. A series of supercharged polypeptides with multiple positive charges was recombinantly produced, and the heparin-neutralizing performance of the polypeptides was evaluated in comparison with PS. It was found that increasing the number of charges significantly enhanced the ability to neutralize heparin and resist the screening effect induced by salt. In particular, the polypeptide bearing 72 charges (K72) exhibited an excellent heparin-neutralizing behavior that was comparable to that of PS. Further in vivo studies revealed that the heparin-triggered bleeding was almost completely alleviated by K72 while a negligible toxic effect was observed. Therefore, such recombinant supercharged polypeptides might replace protamine sulfate as heparin-reversal agents.

Transformative Materials for Interfacial Drug Delivery

Drug delivery systems (DDS) are designed to temporally and spatially control drug availability and activity. They assist in improving the balance between on-target therapeutic efficacy and off-target toxic side effects. DDS aid in overcoming biological barriers encountered by drug molecules upon applying them via various routes of administration. They are furthermore increasingly explored for modulating the interface between implanted (bio)medical materials and host tissue. Herein, an overview of the biological barriers and host-material interfaces encountered by DDS upon oral, intravenous, and local administration is provided, and material engineering advances at different time and space scales to exemplify how current and future DDS can contribute to improved disease treatment are highlighted.

Transformative Materials to Create 3D Functional Human Tissue Models In Vitro in a Reproducible Manner

Recreating human tissues and organs in the petri dish to establish models as tools in biomedical sciences has gained momentum. These models can provide insight into mechanisms of human physiology, disease onset, and progression, and improve drug target validation, as well as the development of new medical therapeutics. Transformative materials play an important role in this evolution, as they can be programmed to direct cell behavior and fate by controlling the activity of bioactive molecules and material properties. Using nature as an inspiration, scientists are creating materials that incorporate specific biological processes observed during human organogenesis and tissue regeneration. This article presents the reader with state-of-the-art developments in the field of in vitro tissue engineering and the challenges related to the design, production, and translation of these transformative materials. Advances regarding (stem) cell sources, expansion, and differentiation, and how novel responsive materials, automated and large-scale fabrication processes, culture conditions, in situ monitoring systems, and computer simulations are required to create functional human tissue models that are relevant and efficient for drug discovery, are described. This paper illustrates how these different technologies need to converge to generate in vitro life-like human tissue models that provide a platform to answer health-based scientific questions.

Anthrenus (s. str.) semipallens sp. nov., a new species from Spain (Coleoptera: Dermestidae: Anthreninae)

During an examination of Spanish Anthrenus spp. held in Andreas Herrmann's private collection, four specimens of a new species were noted: Anthrenus (Anthrenus) semipallens. Images of habitus features, including antenna, are presented and compared with other Anthrenus species thought to occur in Spain. A. semipallens is small so some comparison species could be eliminated courtesy of size. Although A. semipallens doesn't resemble the colour pattern of any other species, the possibility that A. semipallens is an unknown colour variant of a comparison species was considered. The A. semipallens specimens were dissected and the aedeagus compared with aedeagi from all other possible species. There was no similarity. Anthrenus semipallens is a valid new species.

Relevance of Host Cell Surface Glycan Structure for Cell Specificity of Influenza A Viruses

Influenza A viruses (IAVs) initiate infection via binding of the viral hemagglutinin (HA) to sialylated glycans on host cells. HA's receptor specificity towards individual glycans is well studied and clearly critical for virus infection, but the contribution of the highly heterogeneous and complex glycocalyx to virus-cell adhesion remains elusive. Here, we use two complementary methods, glycan arrays and single-virus force spectroscopy (SVFS), to compare influenza virus receptor specificity with virus binding to live cells. Unexpectedly, we found that HA's receptor binding preference does not necessarily reflect virus-cell specificity. We propose SVFS as a tool to elucidate the cell binding preference of IAVs, thereby including the complex environment of sialylated receptors within the plasma membrane of living cells.

Jejunal arteriovenous malformation and multiple acquired extrahepatic portosystemic shunts in a juvenile dog, presenting with melena

A juvenile dog referred with a 1-month history of persistent melena and severe anaemia, was diagnosed with a jejunal arteriovenous malformation, and multiple acquired extrahepatic portosystemic shunts. A midline coeliotomy was performed, the jejunal arteriovenous malformation was localised intraoperatively and was successfully removed via an enterectomy. Histopathology confirmed a true arteriovenous malformation. Despite the initial improvement, the patient developed seizure episodes secondary to hepatic encephalopathy 8 months after surgery. Fifteen months after surgery, the owner opted for euthanasia due to the ongoing seizure episodes. Post-mortem histologic examination of the liver showed features consistent with portal vein hypoplasia. A congenital arteriovenous malformation should be considered as a differential diagnosis in juvenile patients with a chronic history of haemorrhage from the gastrointestinal tract. In addition, acquired portosystemic shunts may occur in patients with portal vein hypoplasia and jejunal arteriovenous malformations.

Respiratory viruses interacting with cells: the importance of electrostatics

The COVID-19 pandemic has rekindled interest in the molecular mechanisms involved in the early steps of infection of cells by viruses. Compared to SARS-CoV-1 which only caused a relatively small albeit deadly outbreak, SARS-CoV-2 has led to fulminant spread and a full-scale pandemic characterized by efficient virus transmission worldwide within a very short time. Moreover, the mutations the virus acquired over the many months of virus transmission, particularly those seen in the Omicron variant, have turned out to result in an even more transmissible virus. Here, we focus on the early events of virus infection of cells. We review evidence that the first decisive step in this process is the electrostatic interaction of the spike protein with heparan sulfate chains present on the surface of target cells: Patches of cationic amino acids located on the surface of the spike protein can interact intimately with the negatively charged heparan sulfate chains, which results in the binding of the virion to the cell surface. In a second step, the specific interaction of the receptor binding domain (RBD) within the spike with the angiotensin-converting enzyme 2 (ACE2) receptor leads to the uptake of bound virions into the cell. We show that these events can be expressed as a semi-quantitative model by calculating the surface potential of different spike proteins using the Adaptive Poison-Boltzmann-Solver (APBS). This software allows visualization of the positive surface potential caused by the cationic patches, which increased markedly from the original Wuhan strain of SARS-CoV-2 to the Omicron variant. The surface potential thus enhanced leads to a much stronger binding of the Omicron variant as compared to the original wild-type virus. At the same time, data taken from the literature demonstrate that the interaction of the RBD of the spike protein with the ACE2 receptor remains constant within the limits of error. Finally, we briefly digress to other viruses and show the usefulness of these electrostatic processes and calculations for cell-virus interactions more generally.

Dual-Action Heteromultivalent Glycopolymers Stringently Block and Arrest Influenza A Virus Infection In Vitro and Ex Vivo

Here, we demonstrate the concerted inhibition of different influenza A virus (IAV) strains using a low-molecular-weight dual-action linear polymer. The 6'-sialyllactose and zanamivir conjugates of linear polyglycerol are optimized for simultaneous targeting of hemagglutinin and neuraminidase on the IAV surface. Independent of IAV subtypes, hemagglutination inhibition data suggest better adsorption of the heteromultivalent polymer than homomultivalent analogs onto the virus surface. Cryo-TEM images imply heteromultivalent compound-mediated virus aggregation. The optimized polymeric nanomaterial inhibits >99.9% propagation of various IAV strains 24 h postinfection in vitro at low nM concentrations and is up to 10000× more effective than the commercial zanamivir drug. In a human lung ex vivo multicyclic infection setup, the heteromultivalent polymer outperforms the commercial drug zanamivir and homomultivalent analogs or their physical mixtures. This study authenticates the translational potential of the dual-action targeting approach using small polymers for broad and high antiviral efficacy.

Programming DNA Circuits for Controlled Immunostimulation through CpG Oligodeoxynucleotide Delivery

Herein, we present a DNA circuit programmed for the delivery of CpG oligodeoxynucleotides (CpG ODNs) with the pharmacological immunostimulation function. The circuit employs a complementary DNA (cDNA) strand to deactivate the biological function of CpG ODNs via hybridization, while T7 exonuclease mediates the activation by hydrolyzing the cDNA and releasing the CpG ODN as an active moiety. We investigated the influence of several factors on the kinetic profile and temporal behavior of the circuit. These include the design of the cDNA strand, the concentration of the DNA duplex, and the concentration of T7 exonuclease. The DNA circuit's in vitro activation resulted in toll-like receptor 9 stimulation in the HEK-engineered cell line, as well as tumor necrosis factor-alpha release by J774A.1 macrophages. By programming the DNA circuit to control the release of the CpG ODN, we achieved an altered pharmacological profile with acute and potent immunostimulation, in comparison to a system without controlled CpG ODN release, which exhibited a slow and delayed response. Our findings demonstrate the potential of DNA circuits in controlling the pharmacological activity of DNA strands for controlled drug delivery.

Fracture Detection in Bio-Glues with Fluorescent-Protein-Based Optical Force Probes

Glues are being used to bond, seal, and repair in industry and biomedicine. The improvement of gluing performance is hence important for the development of new glues with better and balanced property spaces, which in turn necessitates a mechanistic understanding of their mechanical failure. Optical force probes (OFPs) allow the observation of mechanical material damage in polymers from the macro- down to the microscale, yet have never been employed in glues. Here, the development of a series of ratiometric OFPs based on fluorescent-protein-dye and protein-protein conjugates and their incorporation into genetically engineered bio-glues is reported. The OFPs are designed to efficiently modulate Förster resonance energy transfer upon force application thereby reporting on force-induced molecular alterations independent of concentration and fluorescence intensity both spectrally and through their fluorescence lifetime. By fluorescence spectroscopy in solution and in the solid state and by fluorescence lifetime imaging microscopy, stress concentrations are visualized and adhesive and cohesive failure in the fracture zone is differentiated.

Protein Orientation Defines Rectification of Electronic Current via Solid-State Junction of Entire Photosystem-1 Complex

We demonstrate that the direction of current rectification via one of nature's most efficient light-harvesting systems, the photosystem 1 complex (PS1), can be controlled by its orientation on Au substrates. Molecular self-assembly of the PS1 complex using four different linkers with distinct functional head groups that interact by electrostatic and hydrogen bonds with different surface parts of the entire protein PS1 complex was used to tailor the PS1 orientation. We observe an orientation-dependent rectification in the current-voltage characteristics for linker/PS1 molecule junctions. Results of an earlier study using a surface two-site PS1 mutant complex having its orientation set by covalent binding to the Au substrate supports our conclusion. Current-voltage-temperature measurements on the linker/PS1 complex indicate off-resonant tunneling as the main electron transport mechanism. Our ultraviolet photoemission spectroscopy results highlight the importance of the protein orientation for the energy level alignment and provide insight into the charge transport mechanism via the PS1 transport chain.

Nanopore Detection Using Supercharged Polypeptide Molecular Carriers

The analysis at the single-molecule level of proteins and their interactions can provide critical information for understanding biological processes and diseases, particularly for proteins present in biological samples with low copy numbers. Nanopore sensing is an analytical technique that allows label-free detection of single proteins in solution and is ideally suited to applications, such as studying protein-protein interactions, biomarker screening, drug discovery, and even protein sequencing. However, given the current spatiotemporal limitations in protein nanopore sensing, challenges remain in controlling protein translocation through a nanopore and relating protein structures and functions with nanopore readouts. Here, we demonstrate that supercharged unstructured polypeptides (SUPs) can be genetically fused with proteins of interest and used as molecular carriers to facilitate nanopore detection of proteins. We show that cationic SUPs can substantially slow down the translocation of target proteins due to their electrostatic interactions with the nanopore surface. This approach enables the differentiation of individual proteins with different sizes and shapes via characteristic subpeaks in the nanopore current, thus facilitating a viable route to use polypeptide molecular carriers to control molecular transport and as a potential system to study protein-protein interactions at the single-molecule level.

Parahydrogen-Induced Polarization of a Labeled, Cancer-Targeting DNA Aptamer

Enhancing NMR signals of biomacromolecules by hyperpolarization offers exciting opportunities for diagnostic applications. However, their hyperpolarization via parahydrogen remains challenging as specific catalytic interactions are required, which are difficult to tune due to the large size of the biomolecule and its insolubility in organic solvents. Herein, we show the unprecedented hyperpolarization of the cancer-targeting DNA aptamer AS1411. By screening different molecular motifs for an unsaturated label in nucleosides and in DNA oligomers, we were able to identify structural prerequisites for the hyperpolarization of AS1411. Finally, adjusting the polarity of AS1411 by complexing the DNA backbone with amino polyethylene glycol chains allowed the hydrogenation of the label with parahydrogen while the DNA structure remains stable to maintain its biological function. Our results are expected to advance hyperpolarized molecular imaging technology for disease detection in the future.

STAT proteins in cancer: orchestration of metabolism

Reprogrammed metabolism is a hallmark of cancer. However, the metabolic dependency of cancer, from tumour initiation through disease progression and therapy resistance, requires a spectrum of distinct reprogrammed cellular metabolic pathways. These pathways include aerobic glycolysis, oxidative phosphorylation, reactive oxygen species generation, de novo lipid synthesis, fatty acid β-oxidation, amino acid (notably glutamine) metabolism and mitochondrial metabolism. This Review highlights the central roles of signal transducer and activator of transcription (STAT) proteins, notably STAT3, STAT5, STAT6 and STAT1, in orchestrating the highly dynamic metabolism not only of cancer cells but also of immune cells and adipocytes in the tumour microenvironment. STAT proteins are able to shape distinct metabolic processes that regulate tumour progression and therapy resistance by transducing signals from metabolites, cytokines, growth factors and their receptors; defining genetic programmes that regulate a wide range of molecules involved in orchestration of metabolism in cancer and immune cells; and regulating mitochondrial activity at multiple levels, including energy metabolism and lipid-mediated mitochondrial integrity. Given the central role of STAT proteins in regulation of metabolic states, they are potential therapeutic targets for altering metabolic reprogramming in cancer.

CLOUDING OF INTRAOCULAR SILICONE OIL IN THE ABSENCE OF EMULSIFICATION

PURPOSE

To describe intraocular clouding of silicone oil in the absence of emulsification.

METHODS

Retrospective observational case series of patients who received silicone oil injections and developed silicone oil discoloration without emulsification after pars plana vitrectomy. Clinical examinations and physicochemical analyses were performed to find out the common cause for the opaque oil.

RESULTS

Thirteen patients developed silicone oil discoloration after pars plana vitrectomy. It could be traced down that all patients had received silicone oil from one respective production batch. The silicone oil was removed as soon as possible after the changes were detected (range, 8-16 weeks). Gas chromatography flame ionization detector, size exclusion chromatography, and high-performance liquid chromatography analysis showed the absence of low-molecular-weight compounds in the opaque lot. Thermogravimetric analysis revealed the opaque lot was more temperature stable. During the follow-ups, no obvious retinal toxicity could be observed and best-recorded visual acuity improved considerably in 12 patients and was only limited by the underlying retinal pathologic conditions.

CONCLUSION

This is the first report on opacification of intraocular silicone oil without emulsification. This discoloration of silicone oil may disturb vision and prevent proper fundus examination; however, it seems to be a nontoxic phenomenon without serious long-term consequences.

Lipid-DNA Nanoparticles as Drug-Delivery Vehicles for the Treatment of Retinal Diseases

Retinal eye diseases are the leading cause of blindness in the Western world. Up to date, the only efficient treatment for many retinal diseases consists of invasive intravitreal injections of highly concentrated drugs. Despite the fact that these injections are unpleasant for the patients, they potentially cause serious side effects, e.g., infections, bleeding within the eye or retinal detachment, especially when performed on a monthly basis, thus decreasing the injection frequency and lowering the desired drug dose. Therefore, a sustained released at the region of interest with a sustained release is desired. Recently, novel lipid-DNA nanoparticles (NPs) were shown to be an efficient drug delivery platform to the anterior segment of the eye. In this study, we investigated the distribution and tropism of the NPs when applied intravitreally, as a potential medication carrier to the posterior part of the eye. This technology is perfectly suited for the delivery of low molecular weight drugs to the back of the eye, which so far is greatly hindered by fast diffusion rates of the free drugs in the vitreous body and their intrinsically low retainability in ocular tissue. Excellent biodistribution, adherence and presence for up to five days was found for the different tested nanoparticles ex vivo and in vivo. In conclusion, our lipid-DNA based nanocarrier system was able to reach the retina within minutes and penetrate the retina providing potentially safe and long-term carrier systems for small molecules or nucleotide-based therapies.

The Effect of Glass Structure on the Luminescence Spectra of Sm3+-Doped Aluminosilicate Glasses

Peralkaline Sm³⁺-doped aluminosilicate glasses with different network modifier ions (Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Zn²⁺) were investigated to clarify the effect of glass composition and glass structure on the optical properties of the doped Sm³⁺ ions. For this purpose, the Sm³⁺ luminescence emission spectra were correlated with the molecular structure of the glasses derived by molecular dynamics (MD) simulations. The different network modifier ions have a clear and systematic effect on the peak area ratio of the Sm³⁺ emission peaks which correlates with the average rare earth site symmetry in the glasses. The highest site symmetry is found for the calcium aluminosilicate glass. Glasses with network modifier ions of lower and higher ionic radii show a notably lower average site symmetry. The symmetry could be correlated to the rare earth coordination number with oxygen atoms derived by MD simulations. A coordination number of 6 seems to offer the highest average site symmetry. Higher rare earth coordination probabilities with non-bridging oxygen result in an increased splitting of the emission peaks and a notable broadening of the peaks. The zinc containing glass seems to play a special role. The Zn²⁺ ions notably modify the glass structure and especially the rare earth coordination in comparison to the other network modifier ions in the other investigated glasses. The knowledge on how glass structure affects the optical properties of doped rare earth ions can be used to tailor the rare earth absorption and emission spectra for specific applications.

Release of Volatile Cyclopentanone Derivatives from Imidazolidin-4-One Profragrances in a Fabric Softener Application

Imidazolidin-4-ones were investigated as hydrolytically cleavable profragrances to increase the long-lastingness of perfume perception in a fabric softener application. The reaction of different amino acid amides with 2-alkyl- or 2-alkenylcyclopentanones as the model fragrances to be released afforded the corresponding bi- or tricyclic imidazolidin-4-ones as mixtures of diastereoisomers, which were separated by column chromatography. In polar solution, the different stereoisomers equilibrated under thermodynamic conditions to form mixtures with constant isomeric distributions, as shown by NMR spectroscopy. Dynamic headspace analysis on dry cotton demonstrated the controlled fragrance release from the precursors in practical application. Under non-equilibrium conditions (continuous evaporation of the fragrance) and depending on the structure and stereochemistry of the profragrances, the recorded headspace concentrations of the fragrance released from the precursors increased by a factor of 2 up to 100 with respect to the unmodified reference. Prolinamide-based precursors released the highest amount of fragrance and were thus found to be particularly suitable for prolonging the evaporation of cyclopentanone-derived fragrances on a dry cotton surface.

Sonopharmacology: controlling pharmacotherapy and diagnosis by ultrasound-induced polymer mechanochemistry

Active pharmaceutical ingredients are the most consequential and widely employed treatment in medicine although they suffer from many systematic limitations, particularly off-target activity and toxicity. To mitigate these effects, stimuli-responsive controlled delivery and release strategies for drugs are being developed. Fueled by the field of polymer mechanochemistry, recently new molecular technologies enabled the emergence of force as an unprecedented stimulus for this purpose by using ultrasound. In this research area, termed sonopharmacology, mechanophores bearing drug molecules are incorporated within biocompatible macromolecular scaffolds as preprogrammed, latent moieties. This review presents the novelties in controlling drug activation, monitoring, and release by ultrasound, while discussing the limitations and challenges for future developments.

Medical studentś needs for an integration of climate change into the medical curriculum

Background

The impacts of climate change (CC) on health comprise increased human morbidity and mortality. Consequently, physicians need to be systematically trained to address CC in their professional life. Due to lacking research on educational needs of medical students, we developed a survey instrument to assess studentś attitudinal and knowledge-based needs for the integration of CC into medical curricula and their readiness to learn.

Methods

Our survey was administered online to 788 students at the Medical Faculty of Heidelberg University between 06/2021 and 02/2022. Data analyses included descriptive statistics, reliability analyses as well as regression modeling with regard to readiness to learn.

Results

214 students participated in the survey, 170 fully completed datasets were included in the analysis. A majority of students (72.35%) (strongly) agreed that doctors carry a responsibility to address CC in their work setting, while only 4.71% (strongly) agreed, that their current medical training had imparted them with enough skill to do so. Students showed both considerable knowledge and interest in the area of CC, its health impacts, vulnerabilities and clinical adaptation (70.09% correct answers). Knowledge gaps were identified in the areas of health co-benefits and sustainable healthcare (55.53% and 16.71% of correct answers). 79.42% of students want to learn about CC through the integration into existing mandatory courses.

Conclusions

Results encourage the integration of CC topics with a focus on knowledge and professional role development into existing mandatory courses of the medical curriculum. Specifically, they also pinpoint health impacts and adaptation as greatest areas of interest for students and at health co-benefits and sustainable healthcare as areas with least prior knowledge.

Key messages

Climate-sensitive health counselling: a quantitative survey on addressing climate change

Background

Climate change and its mitigation have significant health implications. Hence, medical associations call on physicians to inform the population about health risks of climate change and possible health co-benefits of climate action. However, so far it is unclear what preferences the general public has about climate-sensitive health counselling (CSHC). Therefore, we developed a survey tool to a) characterize experiences of CSHC, b) identify preferences about communication methods and themes, and c) determine associations of socioeconomic characteristics and climate change attitudes with CSHC preferences.

Methods

The tool development for this cross-sectional online-based survey was embedded in a bigger research project on the conceptualization of CSHC, which follows an exploratory mixed-methods design. Results of preceding qualitative interviews about CSHC were integrated into the tool development. After two pilot tests, the tool was administered from April to June 2022 through the population-based HeReCa panel (Health Related Beliefs and Health Care Experiences in Germany), comprising 3200 participants from 5 federal states. Sociodemographic data is available for all participants.

Results

The final tool entails 46 items, sorted into 7 sections. Two sections serve as dependent variables for the association analysis: 13 items about the acceptability of different communicative approaches of CSHC and 18 items on preferences for themes in CSHC. Three sections serve as independent variables for the analysis: attitudes on climate change, level of engagement, and sociodemographic data. Two sections assess experiences with CSHC and preferred information channels to serve as descriptive results.

Conclusions

A rigorous methodology proved helpful for survey development within a mixed methods study. In triangulation with qualitative data, results of the survey will help physicians to deliver CSHC tailored to the preferences of different sociodemographic groups.

Key messages

Design and Functional Analysis of Heterobifunctional Multivalent Phage Capsid Inhibitors Blocking the Entry of Influenza Virus

Multiple conjugation of virus-binding ligands to multivalent carriers is a prominent strategy to construct highly affine virus binders for the inhibition of viral entry into host cells. In a previous study, we introduced rationally designed sialic acid conjugates of bacteriophages (Qβ) that match the triangular binding site geometry on hemagglutinin spike proteins of influenza A virions, resulting in effective infection inhibition in vitro and in vivo. In this work, we demonstrate that even partially sialylated Qβ conjugates retain the inhibitory effect despite reduced activity. These observations not only support the importance of trivalent binding events in preserving high affinity, as supported by computational modeling, but also allow us to construct heterobifunctional modalities. Capsids carrying two different sialic acid ligand–linker structures showed higher viral inhibition than their monofunctional counterparts. Furthermore, capsids carrying a fluorescent dye in addition to sialic acid ligands were used to track their interaction with cells. These findings support exploring broader applications as multivalent inhibitors in the future.

The Mechanochemical Synthesis and Activation of Carbon-Rich π-Conjugated Materials

Mechanochemistry uses mechanical force to break, form, and manipulate chemical bonds to achieve functional transformations and syntheses. Over the last years, many innovative applications of mechanochemistry have been developed. Specifically for the synthesis and activation of carbon-rich π-conjugated materials, mechanochemistry offers reaction pathways that either are inaccessible with other stimuli, such as light and heat, or improve reaction yields, energy consumption, and substrate scope. Therefore, this review summarizes the recent advances in this research field combining the viewpoints of polymer and trituration mechanochemistry. The highlighted mechanochemical transformations include π-conjugated materials as optical force probes, the force-induced release of small dye molecules, and the mechanochemical synthesis of polyacetylene, carbon allotropes, and other π-conjugated materials.

Late-Stage Modification of Aminoglycoside Antibiotics Overcomes Bacterial Resistance Mediated by APH(3') Kinases

The continuous emergence of antimicrobial resistance is causing a threat to patients infected by multidrug‐resistant pathogens. In particular, the clinical use of aminoglycoside antibiotics, broad‐spectrum antibacterials of last resort, is limited due to rising bacterial resistance. One of the major resistance mechanisms in Gram‐positive and Gram‐negative bacteria is phosphorylation of these amino sugars at the 3’‐position by O‐phosphotransferases [APH(3’)s]. Structural alteration of these antibiotics at the 3’‐position would be an obvious strategy to tackle this resistance mechanism. However, the access to such derivatives requires cumbersome multi‐step synthesis, which is not appealing for pharma industry in this low‐return‐on‐investment market. To overcome this obstacle and combat bacterial resistance mediated by APH(3’)s, we introduce a novel regioselective modification of aminoglycosides in the 3’‐position via palladium‐catalyzed oxidation. To underline the effectiveness of our method for structural modification of aminoglycosides, we have developed two novel antibiotic candidates overcoming APH(3’)s‐mediated resistance employing only four synthetic steps.

Ionic Combisomes: A New Class of Biomimetic Vesicles to Fuse with Life

The construction of biomembranes that faithfully capture the properties and dynamic functions of cell membranes remains a challenge in the development of synthetic cells and their application. Here a new concept for synthetic cell membranes based on the self-assembly of amphiphilic comb polymers into vesicles, termed ionic combisomes (i-combisomes) is introduced. These combs consist of a polyzwitterionic backbone to which hydrophobic tails are linked by electrostatic interactions. Using a range of microscopies and molecular simulations, the self-assembly of a library of combs in water is screened. It is discovered that the hydrophobic tails form the membrane's core and force the backbone into a rod conformation with nematic-like ordering confined to the interface with water. This particular organization resulted in membranes that combine the stability of classic polymersomes with the biomimetic thickness, flexibility, and lateral mobility of liposomes. Such unparalleled matching of biophysical properties and the ability to locally reconfigure the molecular topology of its constituents enable the harboring of functional components of natural membranes and fusion with living bacteria to "hijack" their periphery. This provides an almost inexhaustible palette to design the chemical and biological makeup of the i-combisomes membrane resulting in a powerful platform for fundamental studies and technological applications.

Linker Molecules Convert Commercial Fluorophores into Tailored Functional Probes during Biolabelling

Many life‐science techniques and assays rely on selective labeling of biological target structures with commercial fluorophores that have specific yet invariant properties. Consequently, a fluorophore (or dye) is only useful for a limited range of applications, e.g., as a label for cellular compartments, super‐resolution imaging, DNA sequencing or for a specific biomedical assay. Modifications of fluorophores with the goal to alter their bioconjugation chemistry, photophysical or functional properties typically require complex synthesis schemes. We here introduce a general strategy that allows to customize these properties during biolabelling with the goal to introduce the fluorophore in the last step of biolabelling. For this, we present the design and synthesis of ‘linker’ compounds, that bridge biotarget, fluorophore and a functional moiety via well‐established labeling protocols. Linker molecules were synthesized via the Ugi four‐component reaction (Ugi‐4CR) which facilitates a modular design of linkers with diverse functional properties and bioconjugation‐ and fluorophore attachment moieties. To demonstrate the possibilities of different linkers experimentally, we characterized the ability of commercial fluorophores from the classes of cyanines, rhodamines, carbopyronines and silicon‐rhodamines to become functional labels on different biological targets in vitro and in vivo via thiol‐maleimide chemistry. With our strategy, we showed that the same commercial dye can become a photostable self‐healing dye or a sensor for bivalent ions subject to the linker used. Finally, we quantified the photophysical performance of different self‐healing linker–fluorophore conjugates and demonstrated their applications in super‐resolution imaging and single‐molecule spectroscopy.

Mechano-Nanoswitches for Ultrasound-Controlled Drug Activation

Current pharmacotherapy is challenged by side effects and drug resistance issues due to the lack of drug selectivity. Mechanochemistry-based strategies provide new avenues to overcome the related problems by improving drug selectivity. It is recently shown that sonomechanical bond scission enables the remote-controlled drug release from their inactive parent macromolecules using ultrasound (US). To further expand the scope of the US-controlled drug activation strategy, herein a mechano-responsive nanoswitch for the selective activation of doxorubicin (DOX) to inhibit cancer cell proliferation is constructed. As a proof-of-concept, the synthesis, characterization, and US-responsive drug activation evaluation of the mechano-nanoswitch, which provides a blueprint for tailoring nanosystems for force-induced pharmacotherapy is presented.

Structural and functional analysis of the roles of influenza C virus membrane proteins in assembly and budding

Assembly and budding of the influenza C virus is mediated by three membrane proteins: the hemagglutinin-esterase-fusion glycoprotein (HEF), the matrix protein (CM1), and the ion channel (CM2). Here we investigated whether the formation of the hexagonal HEF arrangement, a distinctive feature of influenza C virions is important for virus budding. We used super resolution microscopy and found 250-nm sized HEF clusters at the plasma membrane of transfected cells, which were insensitive to cholesterol extraction and cytochalasin treatment. Overexpression of either CM1, CM2, or HEF caused the release of membrane-enveloped particles. Cryo-electron microscopy of the latter revealed spherical vesicles exhibiting the hexagonal HEF clusters. We subsequently used reverse genetics to identify elements in HEF required for this clustering. We found that deletion of the short cytoplasmic tail of HEF reduced virus titer and hexagonal HEF arrays, suggesting that an interaction with CM1 stabilizes the HEF clusters. In addition, we substituted amino acids at the surface of the closed HEF conformation and identified specific mutations that prevented virus rescue, others reduced virus titers and the number of HEF clusters in virions. Finally, mutation of two regions that mediate contacts between trimers in the in-situ structure of HEF was shown to prevent rescue of infectious virus particles. Mutations at residues thought to mediate lateral interactions were revealed to promote intracellular trafficking defects. Taken together, we propose that lateral interactions between the ectodomains of HEF trimers are a driving force for virus budding, although CM2 and CM1 also play important roles in this process.

CDC50A is required for aminophospholipid transport and cell fusion in mouse C2C12 myoblasts

Myoblast fusion is essential for the formation of multinucleated muscle fibers and is promoted by transient changes in the plasma membrane lipid distribution. However, little is known about the lipid transporters regulating these dynamic changes. Here, we show that proliferating myoblasts exhibit an aminophospholipid flippase activity that is downregulated during differentiation. Deletion of the P4-ATPase flippase subunit CDC50A (also known as TMEM30A) results in loss of the aminophospholipid flippase activity and compromises actin remodeling, RAC1 GTPase membrane targeting and cell fusion. In contrast, deletion of the P4-ATPase ATP11A affects aminophospholipid uptake without having a strong impact on cell fusion. Our results demonstrate that myoblast fusion depends on CDC50A and may involve multiple CDC50A-dependent P4-ATPases that help to regulate actin remodeling.

Characterization of Hantavirus N Protein Intracellular Dynamics and Localization

Hantaviruses are enveloped viruses that possess a tri-segmented, negative-sense RNA genome. The viral S-segment encodes the multifunctional nucleocapsid protein (N), which is involved in genome packaging, intracellular protein transport, immunoregulation, and several other crucial processes during hantavirus infection. In this study, we generated fluorescently tagged N protein constructs derived from Puumalavirus (PUUV), the dominant hantavirus species in Central, Northern, and Eastern Europe. We comprehensively characterized this protein in the rodent cell line CHO-K1, monitoring the dynamics of N protein complex formation and investigating co-localization with host proteins as well as the viral glycoproteins Gc and Gn. We observed formation of large, fibrillar PUUV N protein aggregates, rapidly coalescing from early punctate and spike-like assemblies. Moreover, we found significant spatial correlation of N with vimentin, actin, and P-bodies but not with microtubules. N constructs also co-localized with Gn and Gc albeit not as strongly as the glycoproteins associated with each other. Finally, we assessed oligomerization of N constructs, observing efficient and concentration-dependent multimerization, with complexes comprising more than 10 individual proteins.

High-heat flux ball-pen probe head in ASDEX-Upgrade

A new high heat flux ball-pen probe head installed on the midplane manipulator is currently being used in ASDEX-Upgrade (AUG). The probe was designed to withstand high heat fluxes making possible the investigation of the plasma edge under harsh conditions, such as low power H-mode. Composed of seven pins (four Langmuir probes, mounted in two Mach probe pairs, and three ball-pen probes), the new probe head allows us to measure several plasma parameters simultaneously and with high temporal resolution. A novel method to correct the sheath potential dynamically accounting for the total secondary electron emission is introduced together with applications to obtain the electron temperature and plasma potential profiles. The total secondary electron emission yield is obtained from particle in cell simulations in AUG condition and probe realistic impact angle with respect to the magnetic field. Finally, the probe capability to investigate turbulence around the separatrix of AUG is discussed.

Avian metapneumovirus subtype B vaccination in commercial broiler chicks: heterologous protection and selected host transcription responses to subtype A or B challenge

Avian metapneumovirus (aMPV) causes respiratory disease and drops in egg production in chicken, and is routinely controlled by vaccination. However, the host's immune response to virulent challenge in vaccinated or unvaccinated broiler chickens is poorly characterised. We show that subtype B vaccination offers heterologous (subtype A challenge) and homologous (subtype B challenge) protection. Subtype B challenge causes significantly greater humoral antibody titres in vaccinated and unvaccinated chickens. In turbinate and lung tissues of unvaccinated-challenged chickens, IgA and IgY mRNA transcription was significantly up-regulated after subtype B challenge compared to subtype A. Cellular immunity (CD8-α and CD8-β) gene transcripts were significantly up-regulated during early and later stages of infection from subtype B or subtype A respectively. Immune gene transcriptional responses (IL-1β, IL-6 and IL-18) were significantly up-regulated after challenge. Gene transcription results have shown that mRNA expression levels of CD8-α, CD8-β, TLR3 and IL-6, particularly in turbinate and trachea tissues, are useful parameters to include in future aMPV vaccination-challenge studies.