Analysis of protein-ligand interactions from titrations and nuclear magnetic resonance relaxation dispersions

We present PLIS, a publicly available, open-source software for the determination of protein-ligand dissociation constants that can be used to characterize biological processes or to shed light on biophysical aspects of interactions. PLIS can analyze data from titration experiments monitored by for instance fluorescence spectroscopy or from nuclear magnetic resonance relaxation dispersion experiments. In addition to analysis of experimental data, PLIS includes functionality for generation of synthetic data, useful for understanding how different parameters effect the data in order to better analyze experiments

A ratiometric fluorogenic nanoprobe for real-time quantitative monitoring of lysosomal pH

Lysosomes are known as key players in cellular signalling and act as terminal degradation stations involved in a multitude of cellular processes. Being a highly influential physiological factor, pH is essential in the regulation of lysosome-mediated physiological and pathological processes. Aberrant pH fluctuations are highly related to lysosomal dysfunction that correlates to lysosomal storage diseases and neurodegenerative disorders. As such, real-time quantitative monitoring of lysosomal pH (pHL) is crucial for gaining insight into lysosomal dysfunction but challenging by the lack of effective lysosome-specific probes with high signal fidelity. Toward this end, we have proposed a lysosomal fluorogenic nanoprobe (TR-MP) for reliable ratiometric measuring of pHL. It is fabricated by rational manipulation of fluorescence resonance energy transfer (FRET) in a tailorable nanoplatform. The nanoprobe consists of biocompatible silica nanoparticles assembled with a pH-sensitive rhodamine derivative (RDM-TEOS) as an acceptor and aggregation-induced emission (AIE) fluorophore (TPE-OMe) as a donor to ensure high energy transfer efficiency. Further equipped with cell-penetrating facilitator and morpholine to enable effective cell-internalization and high lysosome affinity of TR-MP. Results show that TR-MP can quantitatively measure pH in a range of 3.0 - 7.0 and detect pHL fluctuations in live cells under various stimuli, as well as real-time monitor pHL during apoptosis.Funding Agencies|STINT Joint China-Sweden Mobility Project [CH2017-7243]; Swedish Research Council (VR)Swedish Research Council [VR 2019-02409, 2020-05437]; China Scholarship Council (CSC)China Scholarship Council; Carl Tryggers Stiftelse [CTS 19:379]; Swedish Government strategic faculty grant in material science (SFO, MATLIU) in Advanced Functional Materials (AFM) (VR) [5.1-2015-5959]; Centre in Nano Science and technology at LiTH (CeNano); LiU Cancer network at Linkoping University</p

Single-wavelength-excited fluorogenic nanoprobe for accurate real-time ratiometric analysis of broad pH fluctuations in mitophagy

Mitophagy has a critical role in maintaining cellular homeostasis through acidic lysosomes engulfing excess or impaired mitochondria, thereby pH fluctuation is one of the most significant indicators for tracking mitophagy. Then such precise pH tracking demands the fluorogenic probe that has tailored contemporaneous features, including mitochondrial-specificity, excellent biocompatibility, wide pH-sensitive range of 8.0-4.0, and especially quantitative ability. However, available molecular probes cannot simultaneously meet all the requirements since it is extremely difficult to integrate multiple functionalities into a single molecule. To fully address this issue, we herein integrate two fluorogenic pH sensitive units, a mitochondria-specific block, cell-penetrating facilitator, and biocompatible segments into an elegant silica nano scaffold, which greatly ensures the applicability for real-time tracking of pH fluctuations in mitophagy. Most significantly, at a single wavelength excitation, the integrated pH-sensitive units have spectra-distinguishable fluorescence towards alkaline and acidic pH in a broad range that covers mitochondrial and lysosomal pH, thus enabling a ratiometric analysis of pH variations during the whole mitophagy. This work also provides constructive insights into the fabrication of advanced fluorescent nanoprobes for diverse biomedical applications.Funding Agencies|Linkoping University</p

Protein interaction, monocyte toxicity and immunogenic properties of cerium oxide crystals with 5% or 14% gadolinium, cobalt oxide and iron oxide nanoparticles - an interdisciplinary approach

Metal oxide nanoparticles are widely used in both consumer products and medical applications, but the knowledge regarding exposure-related health effects is limited. However, it is challenging to investigate nanoparticle interaction processes with biological systems. The overall aim of this project was to improve the possibility to predict exposure-related health effects of metal oxide nanoparticles through interdisciplinary collaboration by combining workflows from the pharmaceutical industry, nanomaterial sciences, and occupational medicine. Specific aims were to investigate nanoparticle-protein interactions and possible adverse immune reactions. Four different metal oxide nanoparticles; CeOx nanocrystals with 5% or 14% Gd, Co3O4, and Fe2O3, were characterized by dynamic light scattering and high-resolution transmission electron microscopy. Nanoparticle-binding proteins were identified and screened for HLA-binding peptides in silico. Monocyte interaction with nanoparticle-protein complexes was assessed in vitro. Herein, for the first time, immunogenic properties of nanoparticle-binding proteins have been characterized. The present study indicates that especially Co3O4-protein complexes can induce both danger signals, verified by the production of inflammatory cytokines and simultaneously bind autologous proteins, which can be presented as immunogenic epitopes by MHC class II. The clinical relevance of these findings should be further evaluated to investigate the role of metal oxide nanoparticles in the development of autoimmune disease. The general workflow identified experimental difficulties, such as nanoparticle aggregate formation and a lack of protein-free buffers suitable for particle characterization, protein analyses, as well as for cell studies. This confirms the importance of future interdisciplinary collaborations.Funding Agencies|Region Ostergotland ALF [LIO-606891]; AFA insurances [150246]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]; Knut and Alice Wallenberg FoundationKnut &amp; Alice Wallenberg Foundation [2012.0083 CTS, 18:399]; Center in Nano Science and Nano technology at LiTH (CeNano) at Linkoping University</p

Cerium Oxide Nanoparticles with Entrapped Gadolinium for High T-1 Relaxivity and ROS-Scavenging Purposes

Gadolinium chelates are employed worldwide today as clinical contrast agents for magnetic resonance imaging. Until now, the commonly used linear contrast agents based on the rare-earth element gadolinium have been considered safe and well-tolerated. Recently, concerns regarding this type of contrast agent have been reported, which is why there is an urgent need to develop the next generation of stable contrast agents with enhanced spin-lattice relaxation, as measured by improved T-1 relaxivity at lower doses. Here, we show that by the integration of gadolinium ions in cerium oxide nanoparticles, a stable crystalline 5 nm sized nanoparticulate system with a homogeneous gadolinium ion distribution is obtained. These cerium oxide nanoparticles with entrapped gadolinium deliver strong T-1 relaxivity per gadolinium ion (T-1 relaxivity, r(1) = 12.0 mM(-1) s(-1)) with the potential to act as scavengers of reactive oxygen species (ROS). The presence of Ce3+ sites and oxygen vacancies at the surface plays a critical role in providing the antioxidant properties. The characterization of radial distribution of Ce3+ and Ce4+ oxidation states indicated a higher concentration of Ce3+ at the nanoparticle surfaces. Additionally, we investigated the ROS-scavenging capabilities of pure gadolinium-containing cerium oxide nanoparticles by bioluminescent imaging in vivo, where inhibitory effects on ROS activity are shown.Funding Agencies|Swedish Research Council VR [2019-02409, 2020-05437]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]; Knut and Alice Wallenberg Foundation KAW [2014.0276, 18:399, 19:379]; Centre in Nanoscience and Nanotechnology at LiTH (CeNano) at Linkoping University; Swedish Foundation for Strategic Research (SSF) research infrastructure fellow program [RIF 140074]</p

Self-Assembly of Metal Nanoparticles in Bacterial Cellulose for the Fabrication of Soft Substrate-Supported Catalysts

The transition to green and sustainable catalysts necessitates efficient and safe preparation techniques using abundant and renewable resources. Many metal nanoparticles (NPs) are excellent catalysts but suffer from poor colloidal stability. NP immobilization or fabrication of metal nanostructures on solid supports can avoid issues with NP aggregation and facilitate the reuse of catalysts, but it may result in a decrease in the catalytic performance of the NPs. Here, we show that well-defined colloidal silver, gold, and platinum NPs can be self-assembled in bacterial nanocellulose (BC) membranes, yielding BC-NP nanocomposites that are highly catalytically active using the reduction of 4-nitrophenol (4-NP) as a model reaction. The large effective surface area of BC enables the assembly of large quantities of NPs, resulting in materials with excellent catalytic performance. To address the mass transport limitations of reactants through the 3D nanofibrillar BC network, the membranes were dissociated using sonication to produce dispersed nanocellulose fibrils. This process dramatically reduced the time required for the adsorption of the NPs from days to minutes. Moreover, the catalytic performance of the nanofibril-supported NPs was drastically improved. A turnover frequency above 21,000 h–1 was demonstrated, which is more than one order of magnitude higher than that for previously reported soft substrate-supported AuNP-based catalytic materials. The ease of fabrication, abundance, and low environmental footprint of the support material, along with reusability, stability, and unprecedented catalytic performance, make BC-NP nanocomposites a compelling option for green and sustainable catalysis

Light-Up Lipid Droplets Dynamic Behaviors Using a Red-Emitting Fluorogenic Probe

Intracellular lipid metabolism occurs in lipid droplets (LDs), which is critical to the survival of cells. Imaging LDs is an intuitive way to understand their physiology in live cells. However, this is limited by the availability of specific probes that can properly visualize LDs in vivo. Here, an LDs-specific red-emitting probe is proposed to address this need, which is not merely with an ultrahigh signal-to-noise (S/N) ratio and a large Stokes shift (up to 214 nm) but also with superior resistance to photobleaching. The probe has been successfully applied to real-time tracking of intracellular LDs behaviors, including fusion, migration, and lipophagy processes. We deem that the proposed probe here offers a new possibility for deeper understanding of LDs-associated behaviors, elucidation of their roles and mechanisms in cellular metabolism, and determination of the transition between adaptive lipid storage and lipotoxicity as well.Funding Agencies|STINT Joint China - Sweden Mobility Project Program [CH2017-7243]; National Natural Science Foundation of ChinaNational Natural Science Foundation of China [21775001, 21705001]; China Scholarship Council (CSC)China Scholarship Council; Swedish Research CouncilSwedish Research Council [VR 2019-02409]; Swedish Government Strategic Faculty Grant in Material Science (SFO, MATLIU) in Advanced Functional Materials (AFM) [5.1-20155959]; Centre in Nano Science and Nano Technology at LiTH (CeNano); LiU Cancer network at Linkoping University</p

Tailorable Membrane-Penetrating Nanoplatform for Highly Efficient Organelle-Specific Localization

Given the breadth of currently arising opportunities and concerns associated with nanoparticles for biomedical imaging, various types of nanoparticles have been widely exploited, especially for cellular/subcellular level probing. However, most currently reported nanoparticles either have inefficient delivery into cells or lack specificity for intracellular destinations. The absence of well-defined nanoplatforms remains a critical challenge hindering practical nano-based bio-imaging. Herein, the authors elaborate on a tailorable membrane-penetrating nanoplatform as a carrier with encapsulated actives and decorated surfaces to tackle the above-mentioned issues. The tunable contents in such a versatile nanoplatform offer huge flexibility to reach the expected properties and functions. Aggregation-induced emission luminogen (AIEgen) is applied to achieve sought-after photophysical properties, specific targeting moieties are installed to give high affinity towards different desired organelles, and critical grafting of cell-penetrating cyclic disulfides (CPCDs) to promote cellular uptake efficiency without sacrificing the specificity. Hereafter, to validate its practicability, the tailored nano products are successfully applied to track the dynamic correlation between mitochondria and lysosomes during autophagy. The authors believe that the strategy and described materials can facilitate the development of functional nanomaterials for various life science applications.Funding Agencies|STINT Joint China-Sweden Mobility Project [CH2017-7243]; Swedish Research Council (VR)Swedish Research Council [VR 2019-02409, 2020-05437]; China Scholarship Council (CSC)China Scholarship Council; Science and Technology Development Fund, Macau SAR [019/2017/AMJ, 0114/2019/A2]; Carl Tryggers Stiftelse [CTS 19:379]; Swedish Government strategic faculty grant in material science (SFO, MATLIU) in Advanced Functional Materials (AFM) (VR) [Dnr. 5.1-2015-5959]; Centre in Nano Science and technology at LiTH (CeNano); LiU Cancer network at Linkoping University</p

The management of sleep disturbances in children with attention-deficit/hyperactivity disorder (ADHD): an update of the literature

Introduction: sleep disorders represent an important comorbidity in individuals with ADHD. While the links between ADHD and sleep disturbances have been extensively investigated, research on the management of sleep disorders in individuals with ADHD is relatively limited, albeit expanding.Areas covered: the authors searched PubMed, Medline, PsycInfo, Embase+Embase Classic, Web of Sciences databases, and clinicaltrials.gov up to 4 January 2024, for randomized controlled trials (RCTs) of any intervention for sleep disorders associated with ADHD. They retained 16 RCTs (eight on pharmacological and eight on non-pharmacological interventions), supporting behavioral intervention and melatonin, and nine ongoing RCTs registered on clinicaltrials.gov.Expert opinion: the pool of RCTs testing interventions for sleep disorders in individuals with ADHD is expanding. However, to inform clinical guidelines, there is a need for additional research in several areas, including 1) RCTs based on a precise phenotyping of sleep disorders; 2) pragmatic RCTs recruiting neurodevelopmental populations representative of those seen in clinical services; 3) trials testing alternative interventions (e.g. suvorexant or light therapy) or ways to deliver them (e.g. online); 4) sequential and longer-term RCTs; 5) studies testing the impact of sleep interventions on outcomes other than sleep; 6) and implementation of advanced evidence synthesis and precision medicine approaches.</p