Wireless power-up and readout from a label-free biosensor.

Wearable and implantable biosensors have rapidly entered the fields of health and biomedicine to diagnose diseases and physiological monitoring. The use of wired medical devices causes surgical complications, which can occur when wires break, become infected, generate electrical noise, and are incompatible with implantable applications. In contrast, wireless power transfer is ideal for biosensing applications since it does not necessitate direct connections between measurement tools and sensing systems, enabling remote use of the biosensors.

Modeling Infrared Spectroscopy of Nucleic Acids: Integrating Vibrational Non-Condon Effects with Machine Learning Schemes.

Vibrational non-Condon effects, which describe how molecular vibrational transitions are influenced by a system's rotational and translational degrees of freedom, are often overlooked in spectroscopy studies of biological macromolecules. In this work, we explore these effects in the modeling of infrared (IR) spectra for nucleic acids in the 1600-1800 cm region. Through electronic structure calculations, we reveal that the transition dipole moments of the C═O and C═C stretching modes in nucleobases are highly sensitive to solvation, hydrogen bonding, and base stacking conditions.

Replacement of Tyrosines by Unnatural Amino Acid Aminophenylalanine Leads to Metal-Mediated Aniline Free Radical Formation in a Copper Amine Oxidase.

Copper amine oxidases (CAOs) catalyze the oxidative deamination of primary amines to aldehyde, ammonia, and hydrogen peroxide as products and are widely distributed in bacteria, plants, and eukaryotes. These enzymes initiate the single turnover, post-translational conversion of an active site tyrosine to the redox cofactor 2,4,5-trihydroxyphenylalanine quinone (TPQ), subsequently employing TPQ to catalyze steady-state amine oxidation. The mechanisms of TPQ biogenesis and steady-state amine oxidation have been studied extensively, with consensus mechanisms proposed for both reactions.

Depletion of cap-binding protein eIF4E dysregulates amino acid metabolic gene expression.

Protein synthesis is metabolically costly and must be tightly coordinated with changing cellular needs and nutrient availability. The cap-binding protein eIF4E makes the earliest contact between mRNAs and the translation machinery, offering a key regulatory nexus. We acutely depleted this essential protein and found surprisingly modest effects on cell growth and recovery of protein synthesis.

Ribosome rescue factor PELOTA modulates translation start site choice for C/EBPα protein isoforms.

Translation initiation at alternative start sites can dynamically control the synthesis of two or more functionally distinct protein isoforms from a single mRNA. Alternate isoforms of the developmental transcription factor CCAAT/enhancer-binding protein α (C/EBPα) produced from different start sites exert opposing effects during myeloid cell development. This choice between alternative start sites depends on sequence features of the transcript, including a regulatory uORF, but the molecular basis is not fully understood.

Dysregulation of amino acid metabolism upon rapid depletion of cap-binding protein eIF4E.

Protein synthesis is a crucial but metabolically costly biological process that must be tightly coordinated with cellular needs and nutrient availability. In response to environmental stress, translation initiation is modulated to control protein output while meeting new demands. The cap-binding protein eIF4E-the earliest contact between mRNAs and the translation machinery-serves as one point of control, but its contributions to mRNA-specific translation regulation remain poorly understood.

Ribosome rescue factor PELOTA modulates translation start site choice and protein isoform levels of transcription factor C/EBP.

Translation initiation at alternative start sites can dynamically control the synthesis of two or more functionally distinct protein isoforms from a single mRNA. Alternate isoforms of the hematopoietic transcription factor CCAAT-enhancer binding protein (C/EBP) produced from different start sites exert opposing effects during myeloid cell development. This alternative initiation depends on sequence features of the transcript, including a regulatory upstream open reading frame (uORF), but the molecular basis is not fully understood.

Multiplexed microfluidic platform for stem-cell derived pancreatic islet β cells.

Stem cell-derived β cells offer an alternative to primary islets for biomedical discoveries as well as a potential surrogate for islet transplantation. The expense and challenge of obtaining and maintaining functional stem cell-derived β cells calls for a need to develop better high-content and high-throughput culture systems. Microphysiological systems (MPS) are promising high-content platforms, but scaling for high-throughput screening and discoveries remain a challenge.

Structure of SARS-CoV-2 M protein in lipid nanodiscs.

SARS-CoV-2 encodes four structural proteins incorporated into virions, spike (S), envelope (E), nucleocapsid (N), and membrane (M). M plays an essential role in viral assembly by organizing other structural proteins through physical interactions and directing them to sites of viral budding. As the most abundant protein in the viral envelope and a target of patient antibodies, M is a compelling target for vaccines and therapeutics.

Validating the Arrhythmogenic Potential of High-, Intermediate-, and Low-Risk Drugs in a Human-Induced Pluripotent Stem Cell-Derived Cardiac Microphysiological System.

Evaluation of arrhythmogenic drugs is required by regulatory agencies before any new compound can obtain market approval. Despite rigorous review, cardiac disorders remain the second most common cause for safety-related market withdrawal. On the other hand, false-positive preclinical findings prohibit potentially beneficial candidates from moving forward in the development pipeline.

Metabolically driven maturation of human-induced-pluripotent-stem-cell-derived cardiac microtissues on microfluidic chips.

The immature physiology of cardiomyocytes derived from human induced pluripotent stem cells (hiPSCs) limits their utility for drug screening and disease modelling. Here we show that suitable combinations of mechanical stimuli and metabolic cues can enhance the maturation of hiPSC-derived cardiomyocytes, and that the maturation-inducing cues have phenotype-dependent effects on the cells' action-potential morphology and calcium handling. By using microfluidic chips that enhanced the alignment and extracellular-matrix production of cardiac microtissues derived from genetically distinct sources of hiPSC-derived cardiomyocytes, we identified fatty-acid-enriched maturation media that improved the cells' mitochondrial structure and calcium handling, and observed divergent cell-source-dependent effects on action-potential duration (APD).

New system for archiving integrative structures.

Structures of many complex biological assemblies are increasingly determined using integrative approaches, in which data from multiple experimental methods are combined. A standalone system, called PDB-Dev, has been developed for archiving integrative structures and making them publicly available. Here, the data standards and software tools that support PDB-Dev are described along with the new and updated components of the PDB-Dev data-collection, processing and archiving infrastructure.

Reversible phosphorylation of cyclin T1 promotes assembly and stability of P-TEFb.

The positive transcription elongation factor b (P-TEFb) is a critical coactivator for transcription of most cellular and viral genes, including those of HIV. While P-TEFb is regulated by 7SK snRNA in proliferating cells, P-TEFb is absent due to diminished levels of CycT1 in quiescent and terminally differentiated cells, which has remained unexplored. In these cells, we found that CycT1 not bound to CDK9 is rapidly degraded.

Kinetic and structural investigations of novel inhibitors of human epithelial 15-lipoxygenase-2.

Human epithelial 15-lipoxygenase-2 (h15-LOX-2, ALOX15B) is expressed in many tissues and has been implicated in atherosclerosis, cystic fibrosis and ferroptosis. However, there are few reported potent/selective inhibitors that are active ex vivo. In the current work, we report newly discovered molecules that are more potent and structurally distinct from our previous inhibitors, MLS000545091 and MLS000536924 (Jameson et al, PLoS One, 2014, 9, e104094), in that they contain a central imidazole ring, which is substituted at the 1-position with a phenyl moiety and with a benzylthio moiety at the 2-position.

Generating and Using Transcriptomically Based Retinal Cell Atlases.

It has been known for over a century that the basic organization of the retina is conserved across vertebrates. It has been equally clear that retinal cells can be classified into numerous types, but only recently have methods been devised to explore this diversity in unbiased, scalable, and comprehensive ways. Advances in high-throughput single-cell RNA sequencing (scRNA-seq) have played a pivotal role in this effort.

A thermodynamic scaling law for electrically perturbed lipid membranes: Validation with steepest entropy ascent framework.

Experimental evidence has demonstrated the ability of transient pulses of electric fields to alter mammalian cell behavior. Strategies with these pulsed electric fields (PEFs) have been developed for clinical applications in cancer therapeutics, in-vivo decellularization, and tissue regeneration. Successful implementation of these strategies involve understanding how PEFs impact the cellular structures and, hence, cell behavior.

Reconstitution of cargo-induced LC3 lipidation in mammalian selective autophagy.

Selective autophagy of damaged mitochondria, protein aggregates, and other cargoes is essential for health. Cargo initiates phagophore biogenesis, which entails the conjugation of LC3 to phosphatidylethanolamine. Current models suggest that clustered ubiquitin chains on a cargo trigger a cascade from autophagic cargo receptors through the core complexes ULK1 and class III phosphatidylinositol 3-kinase complex I, WIPI2, and the ATG7, ATG3, and ATG12ATG5-ATG16L1 machinery of LC3 lipidation.

Chaperone-mediated autophagy prevents collapse of the neuronal metastable proteome.

Components of the proteostasis network malfunction in aging, and reduced protein quality control in neurons has been proposed to promote neurodegeneration. Here, we investigate the role of chaperone-mediated autophagy (CMA), a selective autophagy shown to degrade neurodegeneration-related proteins, in neuronal proteostasis. Using mouse models with systemic and neuronal-specific CMA blockage, we demonstrate that loss of neuronal CMA leads to altered neuronal function, selective changes in the neuronal metastable proteome, and proteotoxicity, all reminiscent of brain aging.