Doublet Spin State Mediated Photoluminescence Upconversion in Organic Radical Donor-Triplet Acceptor Dyads.

Donor-acceptor dyads are promising materials for improving triplet-sensitized photon upconversion due to faster intramolecular energy transfer (ET), which unfortunately competes with charge transfer (CT) dynamics. To circumvent the issue associated with CT, we propose a novel purely organic donor-acceptor dyad, where the CT character is confined within the donor moiety. In this work, we report the synthesis and characterization of a stable organic radical donor-triplet acceptor dyad () consisting of the acceptor perylene () linked to the donor (4--carbazolyl-2,6-dichlorophenyl)-bis(2,4,6-trichlorophenyl)methyl radical ().

Asymmetrical evolution of promoter methylation of mammalian genes after duplication.

Even though gene duplication is a key source of new genes and evolutionary innovation, it is unclear how duplicates survive the period immediately following gene duplication, in which both copies are functionally redundant. In the absence of epigenetic silencing, the abundance of the gene product would double after gene duplication, which would often have deleterious effects. However, recent duplicates exhibit low expression levels, which could be at least partially explained by high levels of promoter methylation.

Identification of the Wnt signal peptide that directs secretion on extracellular vesicles.

Wnt proteins are hydrophobic glycoproteins that are nevertheless capable of long-range signaling. We found that Wnt7a is secreted long distance on the surface of extracellular vesicles (EVs) following muscle injury. We defined a signal peptide region in Wnts required for secretion on EVs, termed exosome-binding peptide (EBP).

Loss of protects against MASLD alone or with alcohol intake by preserving lipid homeostasis.

Background & Aims: Expression of P21, encoded by the gene, has been associated with fibrosis progression in steatotic liver disease (SLD); however, the underlying mechanisms remain unknown. In the present study, we investigated the function of CDKN1A in SLD.

Methods: expression levels were evaluated in different patient cohorts with SLD, fibrosis, and advanced chronic liver disease (ACLD).

Development of a New Vaccine Adjuvant System Based on the Combination of the Synthetic TLR4 Agonist FP20 and a Synthetic QS-21 Variant.

In this study, we formulated an alternative to AS01b by combining FP20, a synthetic TLR4 agonist, and QS21v, a minimal saponin adjuvant, aiming to improve the vaccine efficacy and stability. The phase transition temperature of FP20 was determined by using differential scanning calorimetry to be 43.9 °C, providing a foundation for the formulation process.

Modulatory effects of CNNM4 on protein- l -isoaspartyl- O -methyltransferase repair function during alcohol-induced hepatic damage.

Background And Aims: Alcohol-associated liver disease (ALD) is a leading cause of liver-related mortality worldwide, with limited treatment options beyond abstinence and liver transplantation. Chronic alcohol consumption has been linked to magnesium (Mg 2+ ) deficiency, which can influence liver disease progression. The mechanisms underlying Mg 2+ homeostasis dysregulation in ALD remain elusive.

Mechanistic Insights into Chloride-Dependent Uncaging Reaction of Propargyl and Allene-Protected Substrates by Pd-Complexes.

This study investigates the effect of chloride levels on the mode of action of palladium complexes for the activation of propargyl- and allene-protected fluorophores and chemotherapeutic drugs through uncaging reactions. Four Pd(II) complexes were synthesized and characterized using various spectroscopic techniques to confirm their structure and electronic properties. Kinetic studies and density functional theory calculations revealed that chloride ions in phosphate buffered saline (PBS) significantly enhance catalytic efficiency, particularly for allenyl-protected substrates compared to propargylic counterparts.

Opposed Aromatic Surfaces Behave as Independent Binding Sites for Carbohydrate Stacking: Analysis of Sandwich-like CH/π/CH Complexes.

CH/π bonds are versatile elements for the construction of complex molecular architectures, thus playing key roles in many biomolecular recognition processes. Although seldom acknowledged, aromatic units are inherently bivalent and can participate in CH/π bonds through either face simultaneously, leading to the formation of stacking complexes. This sandwich-like arrangement is by far the most common in natural complexes and could potentially lead to negative cooperativity due to unfavorable polarization or electrostatic effects, especially when polarized CH fragments are involved.

Exploring Glycan-Lectin Interactions in Natural-Like Environments: A View Using NMR Experiments Inside Cell and on Cell Surface.

Glycan-mediated molecular recognition events are essential for life. NMR is widely used to monitor glycan binding to lectins in solution using isolated glycans and lectins. In this context, we herein explore diverse NMR methodologies, from both the receptor and ligand perspectives, to monitor glycan-lectin interactions under experimental conditions mimicking the native milieu inside cells and on cell surface.

Unveiling the GT114 family: Structural characterization of A075L, a glycosyltransferase from Paramecium bursaria chlorella virus-1 (PBCV-1).

Protein A075L is a β-xylosyltransferase that participates in producing the core of the N-glycans found in VP54, the major viral capsid protein of Paramecium bursaria chlorella virus-1 (PBCV-1). In this study, we present an X-ray crystallographic analysis of the apo form of A075L, along with its complexes with the sugar donor and with a trisaccharide acceptor. The protein structure shows a typical GT-B folding, with two Rossmann-like fold domains, in which the acceptor substrate binds to the N-terminal region, and the nucleotide-sugar donor binds to the C-terminal region.

A resurrected ancestor of Cas12a expands target access and substrate recognition for nucleic acid editing and detection.

The properties of Cas12a nucleases constrict the range of accessible targets and their applications. In this study, we applied ancestral sequence reconstruction (ASR) to a set of Cas12a orthologs from hydrobacteria to reconstruct a common ancestor, ReChb, characterized by near-PAMless targeting and the recognition of diverse nucleic acid activators and collateral substrates. ReChb shares 53% sequence identity with the closest Cas12a ortholog but no longer requires a T-rich PAM and can achieve genome editing in human cells at sites inaccessible to the natural FnCas12a or the engineered and PAM-flexible enAsCas12a.

The Therapeutic Potential of Adipose-Derived Mesenchymal Stem Cell Secretome in Osteoarthritis: A Comprehensive Study.

Osteoarthritis (OA) is a degenerative joint disease characterized by cartilage degradation and inflammation. This study investigates the therapeutic potential of secretome derived from adipose tissue mesenchymal stem cells (ASCs) in mitigating inflammation and promoting cartilage repair in an in vitro model of OA. Our in vitro model comprised chondrocytes inflamed with TNF.

Albumin reprograms the B cell transcriptional landscape and improves neutrophil antimicrobial function in patients with decompensated cirrhosis.

Background & Aims: Patients with acutely decompensated (AD) cirrhosis are immunocompromised and particularly susceptible to infections. This study investigated the immunomodulatory actions of albumin by which this protein may lower the incidence of infections.

Methods: Blood immunophenotyping was performed in 11 patients with AD cirrhosis and 10 healthy volunteers (HV).

Fission of double-membrane tubes under tension.

The division of a cellular compartment culminates with the scission of a highly constricted membrane neck. Scission requires lipid rearrangements, topology changes, and transient formation of nonbilayer intermediate structures driven by curvature stress. Often, a side effect of this stress is pore-formation, which may lead to content leakage and thus breaching of the membrane barrier function.

A binding site for the antibiotic GE81112 in the ribosomal mRNA channel.

The initiation phase is the rate-limiting step of protein synthesis (translation) and is finely regulated, making it an important drug target. In bacteria, initiation is guided by three initiation factors and involves positioning the start site on the messenger RNA within the P-site on the small ribosomal subunit (30S), where it is decoded by the initiator tRNA. This process can be efficiently inhibited by GE81112, a natural hydrophilic, noncyclic, nonribosomal tetrapeptide.

Systemic messenger RNA replacement therapy is effective in a novel clinically relevant model of acute intermittent porphyria developed in non-human primates.

Objective: Acute intermittent porphyria (AIP) is a rare metabolic disorder caused by haploinsufficiency of hepatic porphobilinogen deaminase (PBGD), the third enzyme of the heme biosynthesis. Individuals with AIP experience neurovisceral attacks closely associated with hepatic overproduction of potentially neurotoxic heme precursors.

Design: We replicated AIP in non-human primates (NHPs) through selective knockdown of the hepatic gene and evaluated the safety and therapeutic efficacy of human PBGD (hPBGD) mRNA rescue.

Beyond basic characterization and omics: Immunomodulatory roles of platelet-derived extracellular vesicles unveiled by functional testing.

Renowned for their role in haemostasis and thrombosis, platelets are also increasingly recognized for their contribution in innate immunity, immunothrombosis and inflammatory diseases. Platelets express a wide range of receptors, which allows them to reach a variety of activation endpoints and grants them immunomodulatory functions. Activated platelets release extracellular vesicles (PEVs), whose formation and molecular cargo has been shown to depend on receptor-mediated activation and environmental cues.

Development of bioactive solid-foam scaffolds from decellularized cartilage with chondrogenic and osteogenic properties.

Full osteochondral regeneration remains a major clinical challenge. Among other experimental cartilage regenerative approaches, decellularized cartilage (DCC) is considered a promising material for generating potentially implantable scaffolds useful as cartilage repair strategy. In this work, we focus on screening and comparing different decellularization methods, aiming to generate DCC potentially useful in biomedical context, and therefore, with biological activity and functional properties in terms of induction of differentiation and regeneration.

Enriching productive mutational paths accelerates enzyme evolution.

Darwinian evolution has given rise to all the enzymes that enable life on Earth. Mimicking natural selection, scientists have learned to tailor these biocatalysts through recursive cycles of mutation, selection and amplification, often relying on screening large protein libraries to productively modulate the complex interplay between protein structure, dynamics and function. Here we show that by removing destabilizing mutations at the library design stage and taking advantage of recent advances in gene synthesis, we can accelerate the evolution of a computationally designed enzyme.

Unprecedented selectivity for homologous lectin targets: differential targeting of the viral receptors L-SIGN and DC-SIGN.

DC-SIGN (CD209) and L-SIGN (CD209L) are two C-type lectin receptors (CLRs) that facilitate SARS-CoV-2 infections as viral co-receptors. SARS-CoV-2 manipulates both DC-SIGN and L-SIGN for enhanced infection, leading to interest in developing receptor antagonists. Despite their structural similarity (82% sequence identity), they function differently.

AlphaFold2 Predicts Alternative Conformation Populations in Green Fluorescent Protein Variants.

Artificial intelligence-based protein structure prediction methods such as AlphaFold2 have emerged as powerful tools for characterizing proteins sequence-structure relationship offering unprecedented opportunities for the molecular interpretation of biological and biochemical phenomena. While initially confined to providing a static representation of proteins through their global free-energy minimum, AlphaFold2 has demonstrated the ability to partially sample conformational landscapes, providing insights into protein dynamics, which is fundamental for interpreting and potentially tuning the function of natural and artificial proteins. In this study, we show that targeted column masking of AlphaFold2's multiple sequence alignment enables the characterization and estimation of the population ratio of the two main conformations of engineered green fluorescent proteins with alternative β-strands.

Protocol for volume correlative light X-ray and electron microscopy of endothelial cells in mouse tissue.

Correlative light and electron microscopy (CLEM) greatly facilitate capturing the ultrastructure of spatially and/or temporally rare events. Here, we present a protocol for targeting regions of interests (ROIs) in tissue endothelial cells (ECs) using X-ray micro-computed tomography (μCT). We describe steps for ROI targeting guided by vasculature patterns and positions of EC nuclei visualized by light and X-ray microscopy.

A class I PI3K signalling network regulates primary cilia disassembly in normal physiology and disease.

Primary cilia are antenna-like organelles which sense extracellular cues and act as signalling hubs. Cilia dysfunction causes a heterogeneous group of disorders known as ciliopathy syndromes affecting most organs. Cilia disassembly, the process by which cells lose their cilium, is poorly understood but frequently observed in disease and upon cell transformation.