Cubosomes and hexosomes stabilized by sorbitan monooleate as biocompatible nanoplatforms against skin metastatic human melanoma.

Nanoparticles have become versatile assets in the medical field, providing notable benefits across diverse medical arenas including controlled drug delivery, imaging, and immunological assays. Among these, non-lamellar lipid nanoparticles, notably cubosomes and hexosomes, showcase remarkable biocompatibility and stability, rendering them as optimal choices for theranostic applications. Particularly, incorporating edge activators like sodium taurocholate enhances the potential of these nanoparticles for dermal and transdermal drug delivery, overcoming the stratum corneum, a first line of defense in our skin. This study reports on the formulation of monoolein-based cubosomes and hexosomes incorporating taurocholate and stabilized by Span 80 and co-encapsulating Chlorin e6 and coenzyme QH for photodynamic therapy in skin metastatic melanoma. The formulations were optimized using small-angle X-ray scattering, and cryo-transmission electron microscopy confirmed the presence of cubosomes or hexosomes, depending on the ratio between taurocholate and Span 80. Furthermore, the co-loaded nanoparticles exhibited high encapsulation efficiencies for both Ce6 and the coenzyme QH. In vitro studies on human melanoma cells (Me45) demonstrated the biocompatibility and photodynamic activity of the loaded formulations. These findings show the possibility of formulating more biocompatible cubosomes and hexosomes for photodynamic therapy in skin cancer treatment.

Hohaiivirga grylli gen. nov., sp. nov., a New Member of the Family Methylobacteriaceae, Isolated from Cricket (Gryllus chinensis).

A Gram-staining negative, non-motile, rod-shaped, oxidase negative and catalase positive strain WL0021T was isolated from cricket (Gryllus chinensis) living in the campus of Hohai University. Strain WL0021T was characterized utilizing a polyphasic taxonomy approach. The major fatty acids (> 5%) for strain WL0021T were C16:0 and summed feature 8, and the major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, phospholipid, two aminolipids, and an unidentified polar lipid. Ubiquinone-10 was detected as the predominant respiratory quinone. The results of 16S rRNA gene phylogenetic analyses revealed that strain WL0021T had the highest sequence similarity of 95.3% to Microvirga flavescens c27j1T and strain WL0021T formed a distinct linage within the family Methylobacteriaceae in the phylogenetic trees. Whole genomic DNA G+C content was 48.3%. Combined with the results from this study, strain WL0021T should represent a novel genus in the family Methylobacteriaceae, for which the name Hohaiivirga grylli gen. nov., sp. nov. (type strain WL0021T=GDMCC 1.2420T =JCM 34655T=MCCC 1K05886T) is proposed.

A cluster-nanozyme-coenzyme system mimicking natural photosynthesis for CO2 reduction under intermittent light irradiation.

Natural photosynthesis utilizes solar energy to convert water and atmospheric CO2 into carbohydrates through all-weather light/dark reactions based on molecule-based enzymes and coenzymes, inspiring extensive development of artificial photosynthesis. However, development of efficient artificial photosynthetic systems free of noble metals, as well as rational integration of functional units into a single system at the molecular level, remain challenging. Here we report an artificial system, the assembly system of Cu6 cluster and cobalt terpyridine complex, that mimics natural photosynthesis through precise integration of nanozyme complexes and ubiquinone (coenzyme Q) on Cu6 clusters. This biomimetic system efficiently reduces CO2 to CO in light reaction, achieving a production rate of 740.7 µmol·g-1·h-1 with high durability for at least 188 hours. Notably, our system realizes the decoupling of light and dark reactions, utilizing the phenol-evolutive coenzyme Q acting as an electron reservoir. By regulating the stabilizer of coenzyme Q, the dark reaction time can be extended up to 8.5 hours, which fully meets the natural day/night cycle requirements. Our findings advance the molecular design of artificial systems that replicate the comprehensive functions of natural photosynthesis.

Roseobacter sinensis sp. nov., a marine bacterium capable to synthesize arachidonic acid.

Strain WL0113T was isolated from surface seawater of the coast of Lianyungang, Jiangsu province, PR China. Strain WL0113T shared highest 16S rRNA gene sequence similarity with Roseobacter insulae YSTF-M11T (98.8%), followed by R. cerasinus AI77T (98.8%), R. ponti MM-7 T (98.0%). Strain WL0113T was Gram-stain-negative, cream, aerobic, non-motile and coccoid- to oval-shaped, and able to grow at pH 6.5-9.0 (optimum, pH 7.0-8.0), at 10-37  °C (optimum, 28 °C) and in the presence of 1-5% (w/v; optimum, 2.5%) NaCl. Ubiquinone-10 was detected as dominant. The main fatty acids (> 5%) of the strain WL0113T were C16:0, iso-C17:0 3OH, C20:4ω6,9,12,15c (arachidonic acid), and summed feature 8 (C18:1ω7c and/or C18:1ω6c). The major polar lipids include phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, glycophospholipid, unknown aminolipid, unknown phospholipid, and two unknown polar lipids. The ANI and dDDH values between strain WL0113T and Roseobacter cerasinus were 80.4% and 23.0%, respectively. The genomic DNA G + C content of strain WL0113T was 63.1%. Based on these data, it is proposed that strain WL0113T represent novel species of the genus Roseobacter, for which the name Roseobacter sinensis sp. nov. is proposed. The type strain is WL0113T (= GDMCC 1.3082T = JCM 35567T).

Randomly methylated ß-cyclodextrin improves water - solubility, cellular protection and mucosa permeability of idebenone.

Neurodegenerative diseases such as Alzheimer's are very common today. Idebenone (IDE) is a potent antioxidant with good potential for restoring cerebral efficiency in cases of these and other medical conditions, but a serious drawback for the clinical use of IDE in neurological disorders lies in its scarce water solubility, which greatly inhibits its bioavailability. In this work, we prepared the inclusion complex of IDE with randomly methylated ß-cyclodextrin (RAMEB), resulting in improved water solubility of the included drug; then its in vitro biological activity and ex vivo permeability was evalutated. The solid complex was characterized through FT-IR spectroscopy, Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC). A 78-fold improvement of the solubility of IDE in water resulted, together with a strong 1:1 host-guest interaction (association constant of 12630 M-1), and dissolution of the complex within 15 min, all evidenced during the in-solution studies. Biological in vitro studies were then performed on differentiated human neuroblastoma cells (SH-SY5Y) subjected to oxidative stress. Pretreatment with IDE/RAMEB positively affected cell viability, promoted the nuclear translocation of Nrf2, and increased the levels of GSH as well as those of the endogenous antioxidant enzymes Mn-SOD and HO-1. Lastly, the complexation significantly improved the permeation of IDE through isolated rat nasal mucosa.

Paracraurococcus lichenis sp. nov., isolated from lichen in Thailand.

A novel bacterium, designated as strain LOR1-02T and isolated from a lichen sample collected from Kham Riang Subdistrict, Kantharawichai District, Maha Sarakham Province, Thailand, underwent thorough investigation utilizing a polyphasic taxonomic approach. Strain LOR1-02T demonstrated growth within a temperature range of 20-42 °C (optimal at 30 °C), pH range of 5.0-7.5 (optimal at pH 7.0), and tolerance to 4.0% (w/v) NaCl. Phylogenetic analysis revealed its close relation to Paracraurococcus ruber JCM 9931T, with a 16S rRNA gene sequence similarity of 97.16%, placing it within the genus Paracraurococcus. The approximate genome size of strain LOR1-02T was determined to be 8.6 Mb, with a G + C content of 70.9 mol%. Additionally, ANIb, ANIm, and AAI values between the whole genomes of strain LOR1-02T and type strains were calculated as 82.6-83.4%, 86.1-86.8%, and 81.4-82.2%, respectively, while the dDDH value was determined to be 26.3-28.5% (C.I. 24.0-31.0%). The predominant fatty acids detected were C18:1ω7c and/or C18:1ω6c, C16:0, and C18:12OH. The major ubiquinone identified was Q-10, and the polar lipids included phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, diphosphatidylglycerol, along with unidentified phosphoaminolipid, lipids, and an amino lipid. Based on comprehensive phenotypic, chemotaxonomic, and genotypic characterization, it is concluded that strain LOR1-02T represents a novel species within the genus Paracraurococcus, for which the name Paracraurococcus lichenis sp. nov. is proposed. The type strain designation is LOR1-02T (= JCM 33121T = NBRC 112776T = TISTR 2503T).

Mesorhizobium koreense sp. nov., Isolated from Soil.

An aerobic, Gram-stain-negative, catalase-positive, rod-shaped, and motile bacteria, designated as a strain WR6T was isolated from soil in Republic of Korea. Strain WR6T grew at temperatures of 10-37°C, at pH of 5.0-9.0, and at NaCl concentrations of 0-3.0% (w/v). Phylogenetic and 16S rRNA gene nucleotide sequence analysis confirmed that strain WR6T affiliated to the genus Mesorhizobium, with the nearest relative being Mesorhizobium waimense ICMP 19557T (98.5%). The genome of strain WR6T was 5,035,462 bp with DNA G+C content of 62.6%. In strain WR6T, Q-10 was sole ubiquinone; summed feature 8 (C18:1ω7c and/or C18:1ω6c) and C19:0 cyclo ω8c were predominant fatty acids; and diphosphatidylglycerol, phosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylcholine, and phosphatidylethanolamine were major polar lipids. Based on these polyphasic taxonomic data, strain WR6T represents a novel species in the genus Mesorhizobium. Accordingly, we propose the name Mesorhizobium koreense sp. nov., with the type strain WR6T (=KCTC 92695T =NBRC 116021T).

Idebenone-Loaded Nanocomposite Microspheres for Nasal Administration-A Perspective in the Treatment of Alzheimer's Disease.

BACKGROUND: Alzheimer's disease results in neurodegeneration and is characterized by an accumulation of abnormal neuritic lesions and intracellular aggregates of hyperphosphorylated Tau proteins in the cerebrum. That leads to progressive decline in memory, thinking, and learning skills. Oxidative stress has been shown to play a significant role in the pathogenesis of Alzheimer's disease. Antioxidants are identified as part of therapeutic strategy to prevent or reduce the disease. Idebenone is a synthetic analogue of coenzyme Q10 with potent antioxidant properties, originally developed for the treatment of Alzheimer's disease and other cognitive disorders. After oral administration idebenone undergoes excessive first-pass metabolism and has a very low bioavailability of only about 1%. The use of an alternative route of administration such as the nasal and its incorporation into a novel carrier (nanocomposite microspheres) will eliminate the problems associated with reduced absorption, stability, and rapid biotransformation and will increase the opportunity for idebenone to realize its therapeutic potential in Alzheimer's disease. METHODS: Idebenone-loaded nanocomposite microspheres were obtained by spray drying. The structures were characterized using laser diffraction, scanning electron microscopy, high-performance liquid chromatography, Fourier-transform infrared spectroscopy, and differential scanning calorimetry. The ability of nanocomposite microspheres to bind human serum albumin was investigated by fluorescence spectroscopy. The mucoadhesive properties of the carrier were also determined. RESULTS: Bioadhesive nanocomposite microparticles with spherical shape, smooth surface, size of 7.37 ± 2.4 µm, and with high production yield, good drug entrapment efficiency, and loading values were obtained. Infrared spectra demonstrated no chemical interactions between idebenone and structure-forming polymers. The ability of particles to bind to human serum albumin depends on their drug loading. CONCLUSIONS: Nanocomposite microspheres were developed as the novel delivery system of idebenone for target nose-to-brain delivery. The obtained carrier may increase the therapeutic potential of idebenone by providing higher concentrations in brain tissue and reducing systemic exposure and side effects.

Oxygen-Binding Sites of Enriched Gold Nanoclusters for Capturing Mitochondrial Reverse Electrons.

Reverse electron transfer (RET), an abnormal backward flow of electrons from complexes III/IV to II/I of mitochondria, causes the overproduction of a reduced-type CoQ to boost downstream production of mitochondrial superoxide anions that leads to ischemia-reperfusion injury (IRI) to organs. Herein, we studied low-coordinated gold nanoclusters (AuNCs) with abundant oxygen-binding sites to form an electron-demanding trapper that allowed rapid capture of electrons to compensate for the CoQ/CoQH2 imbalance during RET. The AuNCs were composed of only eight gold atoms that formed a Cs-symmetrical configuration with all gold atoms exposed on the edge site. The geometry and atomic configuration enhance oxygen intercalation to attain a d-band electron deficiency in frontier orbitals, forming an unusually high oxidation state for rapid mitochondrial reverse electron capture under a transient imbalance of CoQ/CoQH2 redox cycles. Using hepatic IRI cells/animals, we corroborated that the CoQ-like AuNCs prevent inflammation and liver damage from IRI via recovery of the mitochondrial function.

Coenzyme Q10-loaded microcapsules stabilized by glyceryl monostearate and soy protein isolates-flaxseed gum: Characterization, in vitro release and digestive behavior.

This study aimed to stabilize microcapsules with core materials of glyceryl monostearate (GMS) and octyl and decyl glycerate, and wall materials of soy protein isolates (SPI) and flaxseed gum (FG) by complex coacervation method to overcome the drawbacks of coenzyme Q10 (CoQ10). It was demonstrated by the study that the obtained microcapsules were irregular aggregates. Differential scanning calorimetry and x-ray diffraction patterns indicated that CoQ10 was entrapped inside the disordered semisolid cores of microcapsules. The CoQ10 loading and encapsulation efficiency analysis revealed that GMS and FG helped CoQ10 better encapsulated inside the microcapsules. The in vitro release curve showed a "burst" release of CoQ10 absorbed on the surface of microcapsules for the first 180 min, followed by a sustained release of the encapsulated CoQ10. GMS and FG contributed to the sustained release and the release mechanism of the microcapsules was Fickian diffusion. The in vitro simulated digestion demonstrated that the constructed microcapsules improved the bio-accessibility of CoQ10. Finally, due to the protection of GMS and FG, microcapsules had good storage stability. In conclusion, this study emphasized the potential of using new microcapsules to deliver and protect lipophilic ingredients, providing valuable information for developing functional foods with higher bioavailability.

Description of Pseudomarimonas salicorniae sp. nov., Isolated from Salicornia herbacea L. in the Tidal Flat of the Yellow Sea.

A Gram-stain-negative, strictly aerobic, non-motile, rod-shaped, designated strain CAU 1642 T, was isolated from a Salicornia herbacea collected from a tidal flat in the Yellow Sea. Strain CAU 1642 T grew optimally at pH 8.0 and 30 °C. The highest 16S rRNA gene sequence similarity was 97.25%, with Pseudomarinomonas arenosa CAU 1598 T, and phylogenetic analysis indicated that strain CAU 1642 T belongs to the genus Pseudomarinomonas. The major cellular fatty acids were iso-C15:0, iso-C16:0, and summed feature 9 (iso-C17:1ω9c and/or 10-methyl C16:0). Ubiquinone-8 was the major respiratory quinone. The draft genome of strain CAU 1642 T was 4.5 Mb, with 68.7 mol% of G + C content. The phylogenetic, phenotypic, and chemotaxonomic analysis data reveal strain CAU 1642 T to be of a novel genus in the family Lysobacteraceae, with the proposed name Pseudomarinomonas salicorniae sp. nov. with type strain CAU 1642 T (= KCTC 92084 T = MCCC 1K07085T).

Thioclava litoralis sp. nov., a novel species of alphaproteobacterium, isolated from surface seawater.

A Gram-negative, aerobic, rod-shaped, non-motile bacterium, designated as FTW29T, was isolated from surface seawater sampled in Futian district, Shenzhen, China. Growth of strain FTW29T was observed at 15-42 ℃ (optimum, 28-30 ℃), pH 4.0-9.0 (optimum, pH 5.5-7.5) and in the presence of 0.5-10% NaCl (optimum, 3.0% NaCl). Strain FTW29T showed 95.0-96.8% 16 S rRNA gene sequence similarity to various type strains of the genera Thioclava, Sinirhodobacter, Rhodobacter, Haematobacter and Frigidibacter of the family Paracoccaceae, and its most closely related strains were Thioclava pacifica DSM 10,166T (96.8%) and Thioclava marina 11.10-0-13T (96.7%). The phylogenomic tree constructed on the bac120 gene set showed that strain FTW29T formed a clade with the genus Thioclava, with a bootstrap value of 100%. The evolutionary distance values between FTW29T and type strains of the genus Thioclava were 0.17-0.19, which are below the recommended standard (0.21-0.23) for defining a novel genus in the family Paracoccaceae. In strain FTW29T, the major fatty acids identified were summed feature 8 (C18:1ω7c) and C16:0, and the predominant respiratory quinones were ubiquinone-10 and ubiquinone-9. The composition of polar lipids in strain FTW29T included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unidentified phospholipid, an unidentified aminolipid, two unidentified glycolipids and an unidentified lipid. The genome of strain FTW29T comprised one circle chromosome and six plasmids, with a G + C content of 61.4%. The average nucleotide identity, average amino acid identity, and digital DNA-DNA hybridization values between strain FTW29T and seven type strains of the genus Thioclava were 76.6-78.4%, 53.2-56.4% and 19.3-20.4%, respectively. Altogether, the phenotypic, phylogenetic and chemotaxonomic evidence illustrated in this study suggested that strain FTW29T represents a novel species of the genus Thioclava, with the proposed name Thioclava litoralis sp. nov. The type strain is FTW29T (= KCTC 82,841T = MCCC 1K08523T).

Molecular mechanism of the ischemia-induced regulatory switch in mammalian complex I.

Respiratory complex I is an efficient driver for oxidative phosphorylation in mammalian mitochondria, but its uncontrolled catalysis under challenging conditions leads to oxidative stress and cellular damage. Ischemic conditions switch complex I from rapid, reversible catalysis into a dormant state that protects upon reoxygenation, but the molecular basis for the switch is unknown. We combined precise biochemical definition of complex I catalysis with high-resolution cryo-electron microscopy structures in the phospholipid bilayer of coupled vesicles to reveal the mechanism of the transition into the dormant state, modulated by membrane interactions. By implementing a versatile membrane system to unite structure and function, attributing catalytic and regulatory properties to specific structural states, we define how a conformational switch in complex I controls its physiological roles.

Mitochondrial respiratory complex I can be inhibited via bypassing the ubiquinone-accessing tunnel.

Mitochondrial NADH-ubiquinone oxidoreductase (complex I) couples electron transfer from NADH to ubiquinone with proton translocation in its membrane part. Structural studies have identified a long (~ 30 Å), narrow, tunnel-like cavity within the enzyme, through which ubiquinone may access a deep reaction site. Although various inhibitors are considered to block the ubiquinone reduction by occupying the tunnel's interior, this view is still debatable. We synthesized a phosphatidylcholine-quinazoline hybrid compound (PC-Qz1), in which a quinazoline-type toxophore was attached to the sn-2 acyl chain to prevent it from entering the tunnel. However, PC-Qz1 inhibited complex I and suppressed photoaffinity labeling by another quinazoline derivative, [125I]AzQ. This study provides further experimental evidence that is difficult to reconcile with the canonical ubiquinone-accessing tunnel model.

Location and interaction of idebenone and mitoquinone in a membrane similar to the inner mitochondrial membrane. Comparison with ubiquinone 10.

Oxygen is essential for aerobic life on earth but it is also the origin of harmful reactive oxygen species (ROS). Ubiquinone is par excellence the endogenous cellular antioxidant, but a very hydrophobic one. Because of that, other molecules have been envisaged, such as idebenone (IDE) and mitoquinone (MTQ), molecules having the same redox active benzoquinone moiety but higher solubility. We have used molecular dynamics to determine the location and interaction of these molecules, both in their oxidized and reduced forms, with membrane lipids in a membrane similar to that of the mitochondria. Both IDE and reduced IDE (IDOL) are situated near the membrane interface, whereas both MTQ and reduced MTQ (MTQOL) locate in a position adjacent to the phospholipid hydrocarbon chains. The quinone moieties of both ubiquinone 10 (UQ10) and reduced UQ10 (UQOL10) in contraposition to the same moieties of IDE, IDOL, MTQ and MTQOL, located near the membrane interphase, whereas the isoprenoid chains remained at the middle of the hydrocarbon chains. These molecules do not aggregate and their functional quinone moieties are located in the membrane at different depths but near the hydrophobic phospholipid chains whereby protecting them from ROS harmful effects.

Structural Reconstruction of E. coli Ubi Metabolon Using an AlphaFold2-Based Computational Framework.

Ubiquinone (UQ) is a redox polyisoprenoid lipid found in the membranes of bacteria and eukaryotes that has important roles, notably one in respiratory metabolism, which sustains cellular bioenergetics. In Escherichia coli, several steps of the UQ biosynthesis take place in the cytosol. To perform these reactions, a supramolecular assembly called Ubi metabolon is involved. This latter is composed of seven proteins (UbiE, UbiG, UbiF, UbiH, UbiI, UbiJ, and UbiK), and its structural organization is unknown as well as its protein stoichiometry. In this study, a computational framework has been designed to predict the structure of this macromolecular assembly. In several successive steps, we explored the possible protein interactions as well as the protein stoichiometry, to finally obtain a structural organization of the complex. The use of AlphaFold2-based methods combined with evolutionary information enabled us to predict several models whose quality and confidence were further analyzed using different metrics and scores. Our work led to the identification of a "core assembly" that will guide functional and structural characterization of the Ubi metabolon.

High-resolution in situ structures of mammalian respiratory supercomplexes.

Mitochondria play a pivotal part in ATP energy production through oxidative phosphorylation, which occurs within the inner membrane through a series of respiratory complexes1-4. Despite extensive in vitro structural studies, determining the atomic details of their molecular mechanisms in physiological states remains a major challenge, primarily because of loss of the native environment during purification. Here we directly image porcine mitochondria using an in situ cryo-electron microscopy approach. This enables us to determine the structures of various high-order assemblies of respiratory supercomplexes in their native states. We identify four main supercomplex organizations: I1III2IV1, I1III2IV2, I2III2IV2 and I2III4IV2, which potentially expand into higher-order arrays on the inner membranes. These diverse supercomplexes are largely formed by 'protein-lipids-protein' interactions, which in turn have a substantial impact on the local geometry of the surrounding membranes. Our in situ structures also capture numerous reactive intermediates within these respiratory supercomplexes, shedding light on the dynamic processes of the ubiquinone/ubiquinol exchange mechanism in complex I and the Q-cycle in complex III. Structural comparison of supercomplexes from mitochondria treated under different conditions indicates a possible correlation between conformational states of complexes I and III, probably in response to environmental changes. By preserving the native membrane environment, our approach enables structural studies of mitochondrial respiratory supercomplexes in reaction at high resolution across multiple scales, from atomic-level details to the broader subcellular context.

Polyphasic Investigation of Aliiroseovarius salicola sp. nov., Isolated from Seawater.

A novel Gram-stain-negative, strictly aerobic, short-rod-shaped, and chemo-organoheterotrophic bacterium, designated KMU-50T, was isolated from seawater gathered from Dadaepo Harbor in South Korea. The microorganism grew at 0-4.0% NaCl concentrations (w/v), pH 6.0-8.0, and 4-37 °C. The 16S rRNA gene sequence-based phylogenetic tree demonstrated that the strain KMU-50T is a novel member of the family Roseobacteraceae and were greatly related to Aliiroseovarius crassostreae CV919-312T with sequence similarity of 98.3%. C18:1 ω7c was the main fatty acid and ubiquinone-10 was the only isoprenoid quinone. The dominant polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, two unidentified phospholipids, an unidentified aminolipid, and an unidentified lipid. The genome size of strain KMU-50T was 3.60 Mbp with a DNA G+C content of 56.0%. The average nucleotide identity (ANI) and average amino acid identity (AAI) values between the genomes of strain KMU-50T and its closely related species were 76.0-81.2% and 62.2-81.5%, respectively. The digital DNA-DNA hybridization (dDDH) value of strain KMU-50T with the strain of A. crassostreae CV919-312T was 25.1%. The genome of the strain KMU-50T showed that it encoded many genes involved in the breakdown of bio-macromolecules, thus showing a high potential as a producer of industrially useful enzymes. Consequently, the strain is described as a new species in the genus Aliiroseovarius, for which the name Aliiroseovarius salicola sp. nov., is proposed with the type strain KMU-50T (= KCCM 90480T = NBRC 115482T).

Comparative effectiveness of myocardial patches and intramyocardial injections in treating myocardial infarction with a MitoQ/hydrogel system.

In cardiac tissue engineering, myocardial surface patches and hydrogel intramyocardial injections represent the two primary hydrogel-based strategies for myocardial infarction (MI) treatment. However, the comparative effectiveness of these two treatments remains uncertain. Therefore, this study aimed to compare the effects of the two treatment modalities by designing a simple and reproducible hydrogel cross-linked with γ-PGA and 4-arm-PEG-SG. To improve mitochondrial damage in cardiomyocytes (CMs) during early MI, we incorporated the mitochondria-targeting antioxidant MitoQ into the hydrogel network. The hydrogel exhibited excellent biodegradability, biocompatibility, adhesion, and injectability in vitro. The hydrogel was utilized for rat MI treatment through both patch adhesion and intramyocardial injections. In vivo results demonstrated that the slow release of MitoQ peptide from the hydrogel hindered ROS production in CM, alleviated mitochondrial damage, and enhanced CM activity within 7 days, effectively inhibiting MI progression. Both hydrogel intramyocardial injections and patches exhibited positive therapeutic effects, with intramyocardial injections demonstrating superior efficacy in terms of cardiac function and structure in equivalent treatment cycles. In conclusion, we developed a MitoQ/hydrogel system that is easily prepared and can serve as both a myocardial patch and an intramyocardial injection for MI treatment, showing significant potential for clinical applications.

Rapid HPLC method reveals dynamic shifts in coenzyme Q redox state.

Ubiquinol or coenzyme Q (CoQ) is a lipid-soluble electron carrier in the respiratory chain and an electron acceptor for various enzymes in metabolic pathways that intersect at this cofactor hub in the mitochondrial inner membrane. The reduced form of CoQ is an antioxidant, which protects against lipid peroxidation. In this study, we have optimized a UV-detected HPLC method for CoQ analysis from biological materials, which involves a rapid single-step extraction into n-propanol followed by direct sample injection onto a column. Using this method, we have measured the oxidized, reduced, and total CoQ pools and monitored shifts in the CoQ redox status in response to cell culture conditions and bioenergetic perturbations. We find that hypoxia or sulfide exposure induces a reductive shift in the intracellular CoQ pool. The effect of hypoxia is, however, rapidly reversed by exposure to ambient air. Interventions at different loci in the electron transport chain can induce sizeable redox shifts in the oxidative or reductive direction, depending on whether they are up- or downstream of complex III. We have also used this method to confirm that CoQ levels are higher and more reduced in murine heart versus brain. In summary, the availability of a convenient HPLC-based method described herein will facilitate studies on CoQ redox dynamics in response to environmental, nutritional, and endogenous alterations.