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Human RAD52 (RAD52) is a DNA-binding protein involved in many DNA repair mechanisms and genomic stability maintenance. In the last few years, this protein was discovered to be a promising novel pharmacological target for anticancer strategies. Although the interest in RAD52 has exponentially grown in the previous decade, most information about its structure and mechanism still needs to be elucidated. Here, we report the 2.2 Å resolution cryo-EM reconstruction of the full-length RAD52 (FL-RAD52) protein. This allows us to describe the hydration shell of the N-terminal region of FL-RAD52, which is structured in an undecamer ring. Water molecules coordinate with protein residues to promote stabilization inside and among the protomers and within the inner DNA binding cleft to drive protein-DNA recognition. Additionally, through a multidisciplinary approach involving SEC-SAXS and computational methods, we comprehensively describe the highly flexible and dynamic organization of the C-terminal portion of FL-RAD52. This work discloses unprecedented structural details on the FL-RAD52, which will be critical for characterizing its mechanism of action and inhibitor development, particularly in the context of novel approaches to synthetic lethality and anticancer drug discovery. A cryo-EM reconstruction with 2.2 Å resolution of the full-length RAD52 protein highlights the hydration shell of the DNA-binding region and the highly flexible C-terminal portion, obtained by combining SEC-SAXS and computational methods. [ABSTRACT FROM AUTHOR]

Oxygenic phototrophs perform carbon fixation through the Calvin–Benson cycle. Different mechanisms adjust the cycle and the light‐harvesting reactions to rapid environmental changes. Photosynthetic glyceraldehyde 3‐phosphate dehydrogenase (GAPDH) is a key enzyme in the cycle. In land plants, different photosynthetic GAPDHs exist: the most abundant isoform is formed by A2B2 heterotetramers and the least abundant by A4 homotetramers. Regardless of the subunit composition, GAPDH is the major consumer of photosynthetic NADPH and its activity is strictly regulated. While A4‐GAPDH is regulated by CP12, AB‐GAPDH is autonomously regulated through the C‐terminal extension (CTE) of its B subunits. Reversible inhibition of AB‐GAPDH occurs via the oxidation of a cysteine pair located in the CTE and the substitution of NADP(H) with NAD(H) in the cofactor‐binding site. These combined conditions lead to a change in the oligomerization state and enzyme inhibition. SEC–SAXS and single‐particle cryo‐EM analysis were applied to reveal the structural basis of this regulatory mechanism. Both approaches revealed that spinach (A2B2)n‐GAPDH oligomers with n = 1, 2, 4 and 5 co‐exist in a dynamic system. B subunits mediate the contacts between adjacent tetramers in A4B4 and A8B8 oligomers. The CTE of each B subunit penetrates into the active site of a B subunit of the adjacent tetramer, which in turn moves its CTE in the opposite direction, effectively preventing the binding of the substrate 1,3‐bisphosphoglycerate in the B subunits. The whole mechanism is made possible, and eventually controlled, by pyridine nucleotides. In fact, NAD(H), by removing NADP(H) from A subunits, allows the entrance of the CTE into the active site of the B subunit, hence stabilizing inhibited oligomers. [ABSTRACT FROM AUTHOR]

The common fruit fly Drosophila melanogaster (Dm) is a simple animal species that contributed significantly to the development of neurobiology whose leucine-rich repeat kinase 2 mutants (LRRK2) loss-of-function in the WD40 domain represent a very interesting tool to look into physiopathology of Parkinson’s disease (PD). Accordingly, LRRK2 Dm have also the potential to contribute to reveal innovative therapeutic approaches to its treatment. Withania somnifera Dunal, a plant that grows spontaneously also in Mediterranean regions, is known in folk medicine for its anti-inflammatory and protective properties against neurodegeneration. The aim of this study was to evaluate the neuroprotective effects of its standardized root methanolic extract (Wse) on the LRRK2 loss-of-function Dm model of PD. To this end mutant and wild type (WT) flies were administered Wse, through diet, at different concentrations as larvae and adults (L+/A+) or as adults (L-/A+) only. LRRK2 mutants have a significantly reduced lifespan and compromised motor function and mitochondrial morphology compared to WT flies 1% Wse-enriched diet, administered to Dm LRRK2 as L-/A+and improved a) locomotor activity b) muscle electrophysiological response to stimuli and also c) protected against mitochondria degeneration. In contrast, the administration of Wse to Dm LRRK2 as L+/A+, no matter at which concentration, worsened lifespan and determined the appearance of increased endosomal activity in the thoracic ganglia. These results, while confirming that the LRRK2 loss-of-function in the WD40 domain represents a valid model of PD, reveal that under appropriate concentrations Wse can be usefully employed to counteract some deficits associated with the disease. However, a careful assessment of the risks, likely related to the impaired endosomal activity, is required. [ABSTRACT FROM AUTHOR]

Carbon-based nanomaterials have attracted much interest during the last decade for biomedical applications. Multimodal imaging probes based on carbon nano-onions (CNOs) have emerged as a platform for bioimaging because of their cell-penetration properties and minimal systemic toxicity. Here, we describe the covalent functionalization of CNOs with fluorescein and folic acid moieties for both imaging and targeting cancer cells. The modified CNOs display high brightness and photostability in aqueous solutions and their selective and rapid uptake in two different cancer cell lines without significant cytotoxicity was demonstrated. The localization of the functionalized CNOs in late-endosomes cell compartments was revealed by a correlative approach with confocal and transmission electron microscopy. Understanding the biological response of functionalized CNOs with the capability to target cancer cells and localize the nanoparticles in the cellular environment, will pave the way for the development of a new generation of imaging probes for future biomedical studies. [ABSTRACT FROM AUTHOR]

Background Tubifex tubifex is a widespread annelid characterized by considerable variability in its taxonomic characteristics and by a mixed reproductive strategy, with both parthenogenesis and biparental reproduction. In a molecular phylogenetic analysis, we detected substantial genetic variability among sympatric Tubifex spp. from the Lambro River (Milano, Italy), which we suggested comprise several cryptic species. To gain insights into the evolutionary events that generated this differentiation, we performed a cytogenetic analysis in parallel with a molecular assay. Approximately 80 cocoons of T. tubifex and T. blanchardi were collected and dissected. For each cocoon, we sequenced a fragment of the 16S rRNA from half of the sibling embryos and karyotyped the other half. To generate a robust phylogeny enabling the reconstruction of the evolutionary processes shaping the diversity of these sympatric lineages, we complemented our original 16S rRNA gene sequences with additional COI sequences. Results The chromosome number distribution was consistent with the presence of at least six sympatric euploid chromosome complements (one diploid, one triploid, three tetraploids and one hexaploid), as confirmed by a FISH assay performed with an homologous 18S rDNA probe. All the worms with 2n = 50 chromosomes belonged to an already identified sibling species of T. tubifex, T. blanchardi. The six euploid sets were coherently arranged in the phylogeny, with each lineage grouping specimens with the same chromosome complement. Conclusions These results are compatible with the hypothesis that multiple polyploidization events, possibly enhanced by parthenogenesis, may have driven the evolution of the T. tubifex species complex. [ABSTRACT FROM AUTHOR]

Abstract: Bdelloid rotifers are aquatic microinvertebrates able to cope with the loss of environmental water by entering dormancy, and are thus capable of living in temporary habitats. When water is evaporating, bdelloids contract into “tuns”, silence metabolism and lose water from the body, a condition known as anhydrobiosis. Under controlled conditions, a bdelloid species (Macrotrachela quadricornifera) was made anhydrobiotic, and its morphology was studied by light, confocal and electron microscopy. A compact anatomy characterizes the anhydrobiotic rotifer, resulting in a considerable reduction of its body volume: the internal organs, precisely packed together, occupy the body cavity almost completely and the lumen of hollow organs disappears. Remarkable ultrastructural changes characterize the anhydrobiotic condition. The mitochondria are wholly surrounded by a ring of electron-dense particles, and the epidermal pores, open in the hydrated specimens, become gradually closed by structures similar to epithelial junctions. The cilia are densely packed: microtubules are still identifiable, but the axonemal organization appears disrupted. This is the first extensive comparative study on the morphological changes associated with the anhydrobiosis process in a rotifer, providing the basis for an improved understanding of the processes involved in this extreme adaptation. [Copyright &y& Elsevier]

Tubifex blanchardi Vejdovský, 1891 is a freshwater tubificid, often living in sympatry with Tubifex tubifex (Müller 1774). Although considered from its discovery as a species on its own, its biological status is debated. During the early seventies T. blanchardi was reduced to a mere form of T. tubifex, as a particular case of polymorphism in chaetal pattern. Using classical histological techniques, microdissections of portions of the male genital apparatus and phalloidin staining of dissected copulatory organs we investigated 163 mixed individuals of T. blanchardi and T. tubifex belonging to sympatric populations from the Lambro River (Milan, Northern Italy). The internal morphology of T. blanchardi is described for the first time. Our results show that T. tubifex and T. blanchardi differ in several characters concerning both their external and internal morphology, and in the fine organization of their copulatory organs. Several independent character sets support the separation of T. blanchardi from T. tubifex, suggesting that it is an independent species. This study also supports the idea that T. blanchardi and T. bergi (Hrabě, 1935), another species closely related to T. tubifex, are not conspecific. The observed morphological differences between allopatric populations of T. tubifex are discussed. [ABSTRACT FROM AUTHOR]

Glacier ice worms, Mesenchytraeus solifugus and related species, are the largest glacially obligate metazoans. As one component of cold temperature adaptation, ice worms maintain atypically high energy levels in an apparent mechanism to offset cold temperature-induced lethargy and death. To explore this observation at a mechanistic level, we considered the putative contribution of 5′ adenosine monophosphate deaminase (AMPD), a key regulator of energy metabolism in eukaryotes.We cloned cDNAs encoding ice worm AMPD, generating a fragment encoding 543 amino acids that included a short N-terminal region and complete C-terminal catalytic domain. The predicted ice worm AMPD amino acid sequence displayed conservation with homologues from other mesophilic eukaryotes with notable exceptions. In particular, an ice worm-specific K188E substitution proximal to the AMP binding site likely alters the architecture of the active site and negatively affects the enzyme's activity. Paradoxically, this would contribute to elevated intracellular ATP levels, which appears to be a signature of cold adapted taxa. [ABSTRACT FROM AUTHOR]

Abstract: Tubifex tubifex Müller, 1774 is a cosmopolitan freshwater tubificid widely used as a model in ecotoxicology, population dynamics and developmental biology. It is traditionally recognized as a polytypic species and in Lambro River (Milano, Northern Italy) it occurs in two of the three recognized forms, named “tubifex” and “blanchardi”, alternatively considered as ecological forms or distinct species. To investigate the genetic differentiation of the populations occurring in the Lambro River we sequenced a fragment of the 16S rDNA mitochondrial gene. T. blanchardi, characterized by a low genetic diversity, was genetically segregated from the other sympatric T. tubifex. The ancestral state reconstruction was used to define the morphological traits that support its distinctness. On the contrary, the other T. tubifex from the Lambro community, although morphologically indistinguishable, revealed an astonishing degree of genetic variability, both between and within the three identified clades that proved to be genetically isolated. Using samples from the mixed Lambro River community and from other countries around the world we present an overview of the species complex’ 16S rDNA variability. Our results show that the genetic variability did not sensibly increase widening the data set, suggesting that the Lambro River populations meet the species’ worldwide genetic variability. [Copyright &y& Elsevier]

This is the first phylogenetic analysis of Clitellata using 18S rDNA in combination with morphological data of a selection of species representing Hirudinida, Acanthobdellida, Branchiobdellida, and eight oligochaetous families. The morphological data set includes 48 somatic (light-microscopical) and 34 spermatozoal (ultrastructural) characters. Eight new sperm models belonging to Lumbriculidae (two), Enchytraeidae (two), Phreodrilidae (one), and Tubificidae (three) are compared with the spermatozoal pattern already described among Clitellata. Somatic characters for each species are extracted from both general literature and the original species description. One new 18S sequence of Lumbriculidae and two of Tubificidae are reported, and are aligned together with corresponding sequences of 36 previously studied clitellate taxa. Two polychaete species are used as outgroups. The phylogenetic trees recovered using parsimony and Bayesian inference as optimization criteria of both individual and combined data sets yield largely consistent results. Our combined-data phylogenetic analysis is congruent with recent molecular studies. Somatic and spermatozoal characters contribute to the 18S rDNA phylogeny under both optimization criteria: in resolving the 18S topology, in adding new nodes, and in increasing the support for many groups. Morphological characters in combination with 18S rDNA suggest the following sister-group relationships: (1) between Acanthobdella and Hirudinida, with Branchiobdellida as their plesiomorphic sister group, and (2) between enchytraeids and Propappus, with both taxa grouping at the base of a large assemblage containing Lumbricidae, Lumbriculidae, Branchiobdellida, Acanthobdella, and Hirudinida. Maximum parsimony and maximum likelihood ancestral character state reconstructions on the combined-data tree indicate a new set of somatic and spermatozoal autapomorphies, and propose new evolutionary trends of somatic and spermatological characters. The observed complexity of the spermatozoal characters patterns among oligochaetous clitellates is discussed. This analysis supports a trend from primarily aquatic forms, with bifid chaetae indefinite in number, towards a more terrestrial mode of life leading to a simplification of the chaetae, thus supporting the hypothesis that the first clitellate was an aquatic form. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 154, 1–26. [ABSTRACT FROM AUTHOR]

Abstract: Helicoids in the cocoon membrane of leeches Theromyzon tessulatum and Erpobdella punctata comprise a twisted superposition of layers, each containing a variable number of planes formed by unidirectional fibrils. Straight fibrils intersecting at different angles were displayed in tangential sections through the cocoon wall of each species. When the sectioning angle was below a certain value (i.e., the critical angle), bow-shaped lines apparent in oblique sections were replaced by a succession of layers containing straight fibrils, permitting a direct measurement of step-angle change between successive layers in a helicoid. By this methodology, we determined that no regularities exist in the succession of step-angles or in layer thicknesses within the cocoon membranes, but that the distribution of step-angles between layers was unique for each cocoon type. [Copyright &y& Elsevier]

The spermatozoa and the sperm bundles of the vestimentiferans Riftia pachyptila and Lamellibrachia luymesi (Annelida: Siboglinidae) were studied using several microscopical techniques (transmission and scanning electron microscopy, and confocal microscopy) and compared with some other annelid sperm. The spermatozoa and sperm bundles of both species show a similar structure, but they differ in the dimensions of the components of individual cells and in the number of spermatozoa forming each sperm bundle. The spermatozoa of R. pachyptila and L. luymesi are filiform cells composed, in sequence, by an acrosome in the form of a thread-like helical vesicle, an elongated coiled nucleus surrounded by two helical mitochondria, and a long flagellum. In the spermatozoa of both species, the apical portion of the nucleus is completely devoid of chromatin and is delimited by a thickened nuclear envelope with a fibrillar appearance. Both species have sperm bundles that resemble buds, having a calyx-like portion formed by the helical heads, and a stalk-like portion formed by the tightly packed flagella. A parsimony analysis based on spermatozoal characters showed monophyly of the Siboglinidae and the Vestimentifera. We propose a new set of autapomorphies characterizing vestimentiferan spermatozoa. Our analysis suggests that spermatozoal characters are useful to the understanding of the phylogeny of the group. [ABSTRACT FROM AUTHOR]

Marotta, R., Ferraguti, M. & Erséus, C. (2003). A phylogenetic analysis of Tubificinae and Limnodriloidinae (Annelida, Clitellata, Tubificidae) using sperm and somatic characters. —Zoologica Scripta , 32 , 255–278. The spermatozoa and the sperm aggregates of 13 species belonging to four genera (Smithsonidrilus, Limnodriloides, Thalassodrilides, Doliodrilus ) in the tubificid subfamily Limnodriloidinae (Annelida, Oligochaeta) were studied and compared with the spermatozoal patterns already described in the subfamily Tubificinae. Two characters considered exclusive for the Tubificinae were found in the more spermatologically variable Limnodriloidinae: the production of two kinds of spermatozoa, eusperm and parasperm, and the presence, in the spermathecae, of sperm aggregates formed by a combination of the two sperm types. A parsimony analysis was performed on the spermatozoal data of the species examined and compared with that based on the somatic characters of the same species: a critical revision of the already codified eusperm characters was carried out and the ultrastructure of parasperm was used as a new subset of spermatozoal characters. In a total evidence approach, a further parsimony analysis was run using a matrix combining both sets of characters. This analysis suggested that the double sperm line and the sperm aggregates composed of both eusperm and parasperm may well be homologous in tubificines and limnodriloidines. It thus supported the previous notion that Tubificinae and Limnodriloidinae are closely related and indicated that these subfamilies may be sister taxa. [ABSTRACT FROM AUTHOR]

The cytotoxic action of anticancer drugs can be potentiated by inhibiting DNA repair mechanisms. RAD51 is a crucial protein for genomic stability due to its critical role in the homologous recombination (HR) pathway. BRCA2 assists RAD51 fibrillation and defibrillation in the cytoplasm and nucleus and assists its nuclear transport. BRC4 is a peptide derived from the fourth BRC repeat of BRCA2, and it lacks the nuclear localization sequence. Here, we used BRC4 to (i) reverse RAD51 fibrillation; (ii) avoid the nuclear transport of RAD51; and (iii) inhibit HR and enhance the efficacy of chemotherapeutic treatments. Specifically, using static and dynamic light scattering, transmission electron microscopy, and microscale thermophoresis, we show that BRC4 eroded RAD51 fibrils from their termini through a "domino" mechanism and yielded monomeric RAD51 with a cumulative nanomolar affinity. Using cellular assays (BxPC-3, pancreatic cancer), we show that a myristoylated BRC4 (designed for a more efficient cell entry) abolished the formation of nuclear RAD51 foci. The present study provides a molecular description of RAD51 defibrillation, an essential step in BRCA2-mediated homologous recombination and DNA repair. [ABSTRACT FROM AUTHOR]

The highly efficient peroxidase‐like activity of platinum nanozymes (3–20 nm size) is exploited within the complex cellular environment to catalyze the oxidation of the DAB substrate, producing an electron‐dense signal around the nanozyme surface, upon osmium staining. It is proved that such nanozyme amplification can achieve a catalytic signal enhancement up to 10‐fold, enabling the quick detection of the Pt particles (even of 3 nm size) by transmission electron microscopy (TEM) also at low magnification and across wide fields of view in the intricate intracellular milieu. The developed procedure is ideally suited to overcome standard amplification strategies currently used in TEM analysis, such as gold or silver enhancements. Furthermore, the wide versatility of the Pt‐nanozyme probes in TEM imaging is demonstrated in immuno‐EM and protein trafficking studies, showing their potential to track the subcellular localization of target biomolecules at both low and high magnifications. These results suggest that the use of nanozymes might represent a paradigm shift in the conventional amplification systems currently employed in electron microscopy for cellular analyses, offering enhanced imaging capabilities. [ABSTRACT FROM AUTHOR]

The construction of energetically autonomous artificial protocells is one of the most ambitious goals in bottom-up synthetic biology. Here, we show an efficient manner to build adenosine 5'-triphosphate (ATP) synthesizing hybrid multicompartment protocells. Bacterial chromatophores from Rhodobacter sphaeroides accomplish the photophosphorylation of adenosine 5'-diphosphate (ADP) to ATP, functioning as nanosized photosynthetic organellae when encapsulated inside artificial giant phospholipid vesicles (ATP production rate up to ~100 ATP·s-1 per ATP synthase). The chromatophore morphology and the orientation of the photophosphorylation proteins were characterized by cryo-electron microscopy (cryo-EM) and time-resolved spectroscopy. The freshly synthesized ATP has been employed for sustaining the transcription of a DNA gene, following the RNA biosynthesis inside individual vesicles by confocal microscopy. The hybrid multicompartment approach here proposed is very promising for the construction of full-fledged artificial protocells because it relies on easy-to-obtain and ready-to-use chromatophores, paving the way for artificial simplified-autotroph protocells (ASAPs). [ABSTRACT FROM AUTHOR]

The present study was aimed at characterizing the effects of Withania somnifera (Wse) and Mucuna pruriens (Mpe) on a Drosophila melanogaster model for Amyotrophic Lateral Sclerosis (ALS). In particular, the effects of Wse and Mpe were assessed following feeding the flies selectively overexpressing the wild human copper, zinc-superoxide dismutase (hSOD1-gain-of-function) in Drosophila motoneurons. Although ALS-hSOD1 mutants showed no impairment in life span, with respect to GAL4 controls, the results revealed impairment of climbing behaviour, muscle electrophysiological parameters (latency and amplitude of ePSPs) as well as thoracic ganglia mitochondrial functions. Interestingly, Wse treatment significantly increased lifespan of hSDO1 while Mpe had not effect. Conversely, both Wse and Mpe significantly rescued climbing impairment, and also latency and amplitude of ePSPs as well as failure responses to high frequency DLM stimulation. Finally, mitochondrial alterations were any more present in Wse- but not in Mpe-treated hSOD1 mutants. Hence, given the role of inflammation in the development of ALS, the high translational impact of the model, the known anti-inflammatory properties of these extracts, and the viability of their clinical use, these results suggest that the application of Wse and Mpe might represent a valuable pharmacological strategy to counteract the progression of ALS and related symptoms. [ABSTRACT FROM AUTHOR]

Abstract Herein, we have developed pH-responsive shape-persistent polymersomes made of well-defined amphiphilic poly(ethylene oxide)- block -poly(diisopropylaminoethyl methacrylate- co -furfuryl methacrylate)s PEO- b -P(DPA- co -FMA) by exploiting Diels-Alder chemistry as a robust and simple crosslinking method. Using Photo-induced Copper Mediated Reversible Deactivation Radical Polymerization, we synthesized PEO- b -P(DPA- co -FMA) with optimal block ratios that favor the formation of polymersomes in aqueous media having pH-responsive P(DPA-co-FMA) membranes. Owing to the existence of furfuryl pendant groups within the polymersome membranes, the crosslinking of pH-responsive P(DPA- co -FMA) chains can be achieved via Diels-Alder chemistry. Interestingly, the resulting crosslinked polymersomes swell when the pH in the solution is decreased so that it lies in a biologically relevant range, as was demonstrated by cryogenic transmission electron microscopy. Here, the polymersomes' ability to swell can be controlled by adjusting the amount of crosslinker. A minimum threshold of crosslinking density is needed for the polymersomes to swell while an excess amount of crosslinker quenched their ability to swell. Furthermore, crosslinked polymersomes are capable of encapsulating hydrophilic model drug, such as Rhodamine B. At pH 7.20, due to the compact and hydrophobic membrane, the diffusion of the dye from the interior of the polymersomes to the media is minimized, while the pronation of PDPA at an acidic pH of 4.00, enables a permeable membrane, allowing the loaded cargo to leak much more quickly. The shape-persistent polymersomes that we developed herein, are a promising nano-platform for use in drug delivery applications. Graphical abstract Image 1 Highlights • PDPA-based polymer is synthesized by photo-induced living radical polymerization. • PEO- b -PDPA self-assembles in water to form either micelles or polymersomes. • The membranes of pH-responsive polymersomes are crosslinked by Diels-Alder Chemistry. • Crosslinked polymersomes reversibly swell upon the switching the pH of the media. • Crosslinked polymersomes show the pH-triggered release of pre-loaded hydrophilic dye. [ABSTRACT FROM AUTHOR]

DNA repair protein RAD51 is a key player in the homologous recombination pathway. Upon DNA damage, RAD51 is transported into the nucleus by BRCA2, where it can repair DNA double‐strand breaks. Due to the structural complexity and dynamics, researchers have not yet clarified the mechanistic details of every step of RAD51 recruitment and DNA repair. RAD51 possesses an intrinsic tendency to form oligomeric structures, which make it challenging to conduct biochemical and biophysical investigations. Here, for the first time, we report on the isolation and characterization of a human monomeric RAD51 recombinant form, obtained through a double mutation, which preserves the protein's integrity and functionality. We investigated different buffers to identify the most suitable condition needed to definitively stabilize the monomer. The monomer of human RAD51 provides the community with a unique biological tool for investigating RAD51‐mediated homologous recombination, and paves the way for more reliable structural, mechanistic, and drug discovery studies. [ABSTRACT FROM AUTHOR]

DNA repair protein RAD51 is a key player in the homologous recombination pathway. Upon DNA damage, RAD51 is transported into the nucleus by BRCA2, where it can repair DNA double‐strand breaks. Due to the structural complexity and dynamics, researchers have not yet clarified the mechanistic details of every step of RAD51 recruitment and DNA repair. RAD51 possesses an intrinsic tendency to form oligomeric structures, which make it challenging to conduct biochemical and biophysical investigations. Here, for the first time, we report on the isolation and characterization of a human monomeric RAD51 recombinant form, obtained through a double mutation, which preserves the protein's integrity and functionality. We investigated different buffers to identify the most suitable condition needed to definitively stabilize the monomer. The monomer of human RAD51 provides the community with a unique biological tool for investigating RAD51‐mediated homologous recombination, and paves the way for more reliable structural, mechanistic, and drug discovery studies. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Drosophila PINK1B9 mutant is a model for Parkinson's disease. • The adult crop organ is an important and essential part of the gut. • PINK1B9 flies show morphological and functional impairment in the crop muscle. • PINK1B9 flies show an impairment in the 5-HT circuitry. • Mucuna pruriens extract rescues the crop impairment. Abstract Despite its great potentiality, little attention has been paid to modelling gastrointestinal symptoms of Parkinson's disease (PD) in Drosophila melanogaster (Dm). Our previous studies on standardized Mucuna pruriens extract (Mpe) have shown usefulness in the Drosophila model of PD. In this communication, we provide new information on the effect of Mpe on basal and serotonin treated contractions in the crop (i.e., an important and essential part of the gut) in Drosophila PD mutant for PTEN-induced putative kinase 1 (PINK1B9) gene. The effect of Mpe on PINK1B9 supplied with standard diet to larvae and/or adults, were assayed on 10–15 days old flies. Conversely from what we observed in the wild type flies, recordings demonstrated that exogenous applications of serotonin on crop muscles of untreated PINK1B9 affect neither the frequency nor the amplitude of the crop contraction, while the same muscle parameters are enhanced following brain injections of serotonin, thus suggesting that PINK1B9 mutants may likely have an impairment in the serotonergic pathways. Also, the mitochondrial morphology in the crop muscles is strongly compromised, as demonstrated by the transmission electron microscopy analysis. The Mpe treatment rescued the crop muscle parameters and also the mitochondrial morphology when supplied to both larvae and adults. Overall, this study strengthens the relevance of using PINK1B9 Dm as a translational model to study the gastrointestinal symptoms in PD and also confirms the useful employment of M. pruriens for PD treatment. [ABSTRACT FROM AUTHOR]

The fruit fly Drosophila melanogaster (Dm) mutant for PTEN-induced putative kinase 1 (PINK1B9) gene is a powerful tool to investigate physiopathology of Parkinson's disease (PD). Using PINK1B9 mutant Dm we sought to explore the effects of Mucuna pruriens methanolic extract (Mpe), a L-Dopa-containing herbal remedy of PD. The effects of Mpe on PINK1B9 mutants, supplied with standard diet to larvae and adults, were assayed on 3–6 (I), 10–15 (II) and 20–25 (III) days old flies. Mpe 0.1% significantly extended lifespan of PINK1B9 and fully rescued olfactory response to 1-hexanol and improved climbing behavior of PINK1B9 of all ages; in contrast, L-Dopa (0.01%, percentage at which it is present in Mpe 0.1%) ameliorated climbing of only PINK1B9 flies of age step II. Transmission electron microscopy analysis of antennal lobes and thoracic ganglia of PINK1B9 revealed that Mpe restored to wild type (WT) levels both T-bars and damaged mitochondria. Western blot analysis of whole brain showed that Mpe, but not L-Dopa on its own, restored bruchpilot (BRP) and tyrosine hydroxylase (TH) expression to age-matched WT control levels. These results highlight multiple sites of action of Mpe, suggesting that its effects cannot only depend upon its L-Dopa content and support the clinical observation of Mpe as an effective medication with intrinsic ability of delaying the onset of chronic L-Dopa-induced long-term motor complications. Overall, this study strengthens the relevance of using PINK1B9 Dm as a translational model to study the properties of Mucuna pruriens for PD treatment. [ABSTRACT FROM AUTHOR]

The architecture and structural mechanics of the cell nucleus are defined by the nuclear lamina, which is formed by A- and B-type lamins. Recently, gene duplication and protein overexpression of lamin B1 (LB1) have been reported in pedigrees widi autosomal dominant leukodystrophy (ADLD). However, how the overexpression of LB1 affects nuclear mechanics and function and how it may result in pathology remain unexplored. Here, we report diat in primary human skin fibroblasts derived from ADLD patients, LB1, but not other lamins, is overexpressed at die nuclear lamina and specifically enhances nuclear stiffness. Transient transfection of LB1 in HEK293 and neuronal N2a cells mimics die mechanical phenotype of ADLD nuclei. Notably, in ADLD fibroblasts, reducing LB1 protein levels by shRNA knockdown restores elasticity values to diose indistinguishable from control fibroblasts. Moreover, isolated nuclei from ADLD fibroblasts display a reduced nuclear ion channel open probability on voltage-step application, suggesting diat biophysical changes induced by LB1 overexpression may alter nuclear signaling cascades in somatic cells. Overall, die overexpression of LB1 in ADLD cells alters nuclear mechanics and is linked to changes in nuclear signaling, which could help explain die padiogenesis of diis disease. [ABSTRACT FROM AUTHOR]

The article titled "Platinum Nanozyme Probes for Cellular Imaging by Electron Microscopy" in Small Science introduces a new technique for improving the identification of specific cellular elements in transmission electron microscopy. The authors, Mauro Moglianetti, Pier Paolo Pompa, and their colleagues, present the use of platinum nanozyme probes as an innovative method that surpasses traditional amplification methods in electron microscopy. This advancement offers enhanced imaging capabilities for comprehensive cellular examinations. The article is authored by a diverse group of researchers, including Elisa De Luca, Deborah Pedone, Anna Scarsi, Roberto Marotta, Federico Catalano, Doriana Debellis, Lorenzo Cursi, Benedetto Grimaldi, Mauro Moglianetti, and Pier Paolo Pompa. [Extracted from the article]

[Display omitted] Vaccines based on protein antigens have numerous advantages over inactivated pathogens, including easier manufacturing and improved safety. However, purified antigens are weakly immunogenic, as they lack the spatial organization and the associated 'danger signals' of the pathogen. Formulating vaccines as nanoparticles enhances the recognition by antigen presenting cells, boosting the cell-mediated immune response. This study describes a nano-precipitation method to obtain stable protein nanoaggregates with uniform size distribution without using covalent cross-linkers. Nanoaggregates were formed via microfluidic mixing of ovalbumin (OVA) and lipids in the presence of high methanol concentrations. A purification protocol was set up to separate the nanoaggregates from OVA and liposomes, obtained as byproducts of the mixing. The nanoaggregates were characterized in terms of morphology, ζ-potential and protein content, and their interaction with immune cells was assessed in vitro. Antigen-specific T cell activation was over 6-fold higher for nanoaggregates compared to OVA, due in part to the enhanced uptake by immune cells. Lastly, a two-dose immunization with nanoaggregates in mice induced a significant increase in OVA-specific CD8+ T splenocytes compared to soluble OVA. Overall, this work presents for the first time the microfluidic production of lipid-stabilized protein nanoaggregates and provides a proof-of-concept of their potential for vaccination. [ABSTRACT FROM AUTHOR]

Understanding and controlling the interaction between nanoparticles and biological entities is fundamental to the development of nanomedicine applications. In particular, the possibility to realize nanoparticles capable of directly targeting neutral lipid membranes would be advantageous to numerous applications aiming at delivering nanoparticles and their cargos into cells and biological vesicles. Here, we use experimental and computational methodologies to analyze the interaction between liposomes and gold nanoparticles (AuNPs) featuring cationic headgroups in their protecting monolayer. We find that in contrast to nanoparticles decorated with other positively charged headgroups, guanidinium-coated AuNPs can bind to neutral phosphatidylcholine liposomes, inducing nondisruptive membrane permeabilization. Atomistic molecular simulations reveal that this ability is due to the multivalent H-bonding interaction between the phosphate residues of the liposome's phospholipids and the guanidinium groups. Our results demonstrate that the peculiar properties of arginine magic, an effect responsible for the membranotropic properties of some naturally occurring peptides, are also displayed by guanidinium-bearing functionalized AuNPs. Guanidinium-containing macromolecules, such as arginine-rich peptides, have peculiar properties in their interactions with membranes, including efficient translocation. Here the authors show that cationic gold nanoparticles functionalized with guanidinium groups can specifically and nondisruptively interact with phospholipid bilayer membranes. [ABSTRACT FROM AUTHOR]

In plant grana thylakoid membranes Photosystem II (PSII) associates with a variable number of antenna proteins (LHCII) to form different types of supercomplexes (PSII-LHCII), whose organization is dynamically adjusted in response to light cues, with the C2S2 more abundant in high-light and the C2S2M2 in low-light. Paired PSII-LHCII supercomplexes interacting at their stromal surface from adjacent thylakoid membranes were previously suggested to mediate grana stacking. Here, we present the cryo-electron microscopy maps of paired C2S2 and C2S2M2 supercomplexes isolated from pea plants grown in high-light and low-light, respectively. These maps show a different rotational offset between the two supercomplexes in the pair, responsible for modifying their reciprocal interaction and energetic connectivity. This evidence reveals a different way by which paired PSII-LHCII supercomplexes can mediate grana stacking at diverse irradiances. Electrostatic stromal interactions between LHCII trimers almost completely overlapping in the paired C2S2 can be the main determinant by which PSII-LHCII supercomplexes mediate grana stacking in plants grown in high-light, whereas the mutual interaction of stromal N-terminal loops of two facing Lhcb4 subunits in the paired C2S2M2 can fulfil this task in plants grown in low-light. The high-light induced accumulation of the Lhcb4.3 protein in PSII-LHCII supercomplexes has been previously reported. Our cryo-electron microscopy map at 3.8 Å resolution of the C2S2 supercomplex isolated from plants grown in high-light suggests the presence of the Lhcb4.3 protein revealing peculiar structural features of this high-light-specific antenna important for photoprotection. [ABSTRACT FROM AUTHOR]

Driving nanomaterials to specific cell populations is still a major challenge for different biomedical applications. Several strategies to improve cell binding and uptake have been tried thus far by intrinsic material modifications or decoration with active molecules onto their surface. In the present work, we covalently bound the chemokine CXCL5 on fluorescently labeled amino-functionalized SiO2 nanoparticles to precisely targeting CXCR2+ immune cells. We synthesized and precisely characterized the physicochemical features of the modified particles. The presence of CXCL5 on the surface was detected by z-potential variation and CXCL5-specific electron microscopy immunogold labeling. CXCL5-amino SiO2 nanoparticle cell binding and internalization performances were analyzed in CXCR2+ THP-1 cells by flow cytometry and confocal microscopy. We showed improved internalization of the chemokine modified particles in the absence or the presence of serum. This internalization was reduced by cell pre-treatment with free CXCL5. Furthermore, we demonstrated CXCR2+ cell preferential targeting by comparing particle uptake in THP-1 vs. low-CXCR2 expressing HeLa cells. Our results provide the proof of principle that chemokine decorated nanomaterials enhance uptake and allow precise cell subset localization. The possibility to aim at selective chemokine receptor-expressing cells can be beneficial for the diverse pathological conditions involving immune reactions. [ABSTRACT FROM AUTHOR]

Autophagy plays a crucial role in health and disease, regulating central cellular processes such as adaptive stress responses, differentiation, tissue development, and homeostasis. However, the role of autophagy in human physiology is poorly understood, highlighting a need for a model human organ system to assess the efficacy and safety of strategies to therapeutically modulate autophagy. As a complete, cyclically remodelling (mini-)organ, the organ culture of human scalp hair follicles (HFs), which, after massive growth (anagen), spontaneously enter into an apoptosis-driven organ involution (catagen) process, may provide such a model. Here, we reveal that in anagen, hair matrix keratinocytes (MKs) of organ-cultured HFs exhibit an active autophagic flux, as documented by evaluation of endogenous lipidated Light Chain 3B (LC3B) and sequestosome 1 (SQSTM1/p62) proteins and the ultrastructural visualization of autophagosomes at all stages of the autophagy. This autophagic flux is altered during catagen, and genetic inhibition of autophagy promotes catagen development. Conversely, an anti–hair loss product markedly enhances intrafollicular autophagy, leading to anagen prolongation. Collectively, our data reveal a novel role of autophagy in human hair growth. Moreover, we show that organ-cultured scalp HFs are an excellent preclinical research model for exploring the role of autophagy in human tissue physiology and for evaluating the efficacy and tissue toxicity of candidate autophagy-modulatory agents in a living human (mini-)organ. [ABSTRACT FROM AUTHOR]

[Display omitted] After two decades of research in the field of nanomedicine, nanoscale delivery systems for biologicals are becoming clinically relevant tools. Microfluidic-based fabrication processes are replacing conventional techniques based on precipitation, emulsion, and homogenization. Here, the focus is on solid lipid nanoparticles (SLNs) for the encapsulation and delivery of lysozyme (LZ) as a model biologic. A thorough analysis was conducted to compare conventional versus microfluidic-based production techniques, using a 3D-printed device. The efficiency of the microfluidic technique in producing LZ-loaded SLNs (LZ SLNs) was demonstrated: LZ SLNs were found to have a lower size (158.05 ± 4.86 nm vs 180.21 ± 7.46 nm) and higher encapsulation efficacy (70.15 ± 1.65 % vs 53.58 ± 1.13 %) as compared to particles obtained with conventional methods. Cryo-EM studies highlighted a peculiar turtle-like structure on the surface of LZ SLNs. In vitro studies demonstrated that LZ SLNs were suitable to achieve a sustained release over time (7 days). Enzymatic activity of LZ entrapped into SLNs was challenged on Micrococcus lysodeikticus cultures, confirming the stability and potency of the biologic. This systematic analysis demonstrates that microfluidic production of SLNs can be efficiently used for encapsulation and delivery of complex biological molecules. [ABSTRACT FROM AUTHOR]

Sensitized triplet-triplet annihilation based photon up-conversion (TTA-UC) greatly improves the scope and applicability of fluorescence bioimaging by enabling anti-Stokes detection at low powers, thus eliminating the background autofluorescence and limiting the potential damage of the living tissues. Here the authors present a facile, one-step protocol to prepare dual dye-doped, TTA-UC active nanomicelles starting from the commercially available surfactant Kolliphor EL, a component of several FDA approved preparations. These nanosized micelles show an unprecedented up-conversion yield of 6.5% under 0.1 W cm−2 excitation intensity in an aqueous, nondeaerated dispersion. The supramolecular architecture obtained preserves the embedded dyes from oxygen quenching, allowing satisfactory anti-Stokes fluorescence imaging of 3T3 cells. This is the first example of efficient multicomponent up-converters prepared using highly biocompatible materials approved by the international authority, paving the way for the development of new complex and multifunctional materials for advanced theranostics. [ABSTRACT FROM AUTHOR]

Background: Alzheimer disease (AD) and other tauopathies develop cerebral intracellular inclusions of hyperphosphorylated tau. Epidemiological and experimental evidence suggests a clear link between type 2 diabetes mellitus and AD. In AD animal models, tau pathology is exacerbated by metabolic comorbidities, such as insulin resistance and diabetes. Within this context, anitidiabetic drugs, including the widely-prescribed insulin-sensitizing drug metformin, are currently being investigated for AD therapy. However, their efficacy for tauopathy in vivo has not been tested. Results: Here, we report that in the P301S mutant human tau (P301S) transgenic mouse model of tauopathy, chronic administration of metformin exerts paradoxical effects on tau pathology. Despite reducing tau phosphorylation in the cortex and hippocampus via AMPK/mTOR and PP2A, metformin increases insoluble tau species (including tau oligomers) and the number of inclusions with β-sheet aggregates in the brain of P301S mice. In addition, metformin exacerbates hindlimb atrophy, increases P301S hyperactive behavior, induces tau cleavage by caspase 3 and disrupts synaptic structures. Conclusions: These findings indicate that metformin pro-aggregation effects mitigate the potential benefits arising from its dephosphorylating action, possibly leading to an overall increase of the risk of tauopathy in elderly diabetic patients. [ABSTRACT FROM AUTHOR]

Our patient is a 65-year-old woman presenting with bilateral pes cavus, pronounced distal muscle wasting, weakness and areflexia. Electrophysiological findings included diffuse unrecordable motor and sensory responses. While the CMT phenotype was evident, the lack of family history and the severe, but unspecific electrophysiological impairment, was a challenge for genetic diagnosis. A sural nerve biopsy was performed, showing a severe loss of myelinated fibers with residual axons surrounded by myelin outfoldings. Whereas myelin outfoldings are a pathological hallmark of autosomal recessive CMT4B1 and CMT4B2, due to mutations in myotubularin-related 2 ( MTMR2) and 13 ( MTMR13) genes respectively, they may also occur in nerve biopsies from CMT1B patients. By direct sequencing, a novel heterozygous transversion c. 410G>T in MPZ gene was demonstrated, producing an amino acid change from glycine to valine in position 108 (p. G108V). In HeLa cells the fusion P0G108V- EGFP was normally trafficked to the cell membrane, but with decreased P0 adhesion function, compared with wild-type P0, thus supporting a pathogenic role of the new variant. In conclusion this case highlights the relevance, in selected cases, of sural nerve biopsy to orient the genetic/molecular tests, while in vitro analyses may strengthen the pathogenic role of novel mutations. [ABSTRACT FROM AUTHOR]

Summary The fatty acid ethanolamides (FAEs) are lipid mediators present in all organisms and involved in highly conserved biological functions, such as innate immunity, energy balance, and stress control. They are produced from membrane N -acylphosphatidylethanolamines (NAPEs) and include agonists for G protein-coupled receptors (e.g., cannabinoid receptors) and nuclear receptors (e.g., PPAR-α). Here, we report the crystal structure of human NAPE-hydrolyzing phospholipase D (NAPE-PLD) at 2.65 Å resolution, a membrane enzyme that catalyzes FAE formation in mammals. NAPE-PLD forms homodimers partly separated by an internal ∼9-Å-wide channel and uniquely adapted to associate with phospholipids. A hydrophobic cavity provides an entryway for NAPE into the active site, where a binuclear Zn 2+ center orchestrates its hydrolysis. Bile acids bind with high affinity to selective pockets in this cavity, enhancing dimer assembly and enabling catalysis. These elements offer multiple targets for the design of small-molecule NAPE-PLD modulators with potential applications in inflammation and metabolic disorders. [ABSTRACT FROM AUTHOR]

Iron oxide nanocubes (IONCs) representone of the most promisingiron-based nanoparticles for both magnetic resonance image (MRI) andmagnetically mediated hyperthermia (MMH). Here, we have set a protocolto control the aggregation of magnetically interacting IONCs withina polymeric matrix in a so-called magnetic nanobead (MNB) having mesoscalesize (200 nm). By the comparison with individual coated nanocubes,we elucidate the effect of the aggregation on the specific adsorptionrates (SAR) and on the T1and T2relaxation times. We found that while SARvalues decrease as IONCs are aggregated into MNBs but still keepingsignificant SAR values (200 W/g at 300 kHz), relaxation times showvery interesting properties with outstanding values of r2/r1ratio for the MNBs withrespect to single IONCs. [ABSTRACT FROM AUTHOR]

Becauseof the growing potential of nanoparticles in biologicaland medical applications, tuning and directing their properties towarda high compatibility with the aqueous biological milieu is of remarkablerelevance. Moreover, the capability to combine nanocrystals (NCs)with biomolecules, such as proteins, offers great opportunities todesign hybrid systems for both nanobiotechnology and biomedical technology.Here we report on the application of the micelle-to-vesicle transition(MVT) method for incorporation of hydrophobic, red-emitting CdSe@ZnSNCs into the bilayer of liposomes. This method enabled the constructionof a novel hybrid proteo–NC–liposome containing, asmodel membrane protein, the photosynthetic reaction center (RC) of Rhodobacter sphaeroides. Electron microscopy confirmed theinsertion of NCs within the lipid bilayer without significantly alteringthe structure of the unilamellar vesicles. The resulting aqueous NC–liposomesuspensions showed low turbidity and kept unaltered the wavelengthsof absorbance and emission peaks of the native NCs. A relative NCfluorescence quantum yield up to 8% was preserved after their incorporationin liposomes. Interestingly, in proteo–NC–liposomes,RC is not denatured by Cd-based NCs, retaining its structural andfunctional integrity as shown by absorption spectra and flash-inducedcharge recombination kinetics. The outlined strategy can be extendedin principle to any suitably sized hydrophobic NC with similar surfacechemistry and to any integral protein complex. Furthermore, the proposedapproach could be used in nanomedicine for the realization of theranosticsystems and provides new, interesting perspectives for understandingthe interactions between integral membrane proteins and nanoparticles,i.e., in nanotoxicology studies. [ABSTRACT FROM AUTHOR]

Parkinson’s disease (PD) is one of the most common neurodegenerative disease characterized by the clinical triad: tremor, akinesia and rigidity. Several studies have suggested that PD patients show disturbances in olfaction at the earliest onset of the disease. The fruit fly Drosophila melanogaster is becoming a powerful model organism to study neurodegenerative diseases. We sought to use this system to explore olfactory dysfunction, if any, in PINK1 mutants, which is a model for PD. PINK1 mutants display many important diagnostic symptoms of the disease such as akinetic motor behavior. In the present study, we describe for the first time, to the best of our knowledge, neurophysiological and neuroanatomical results concerning the olfactory function in PINK1 mutant flies. Electroantennograms were recorded in response to synthetic and natural volatiles (essential oils) from groups of PINK1 mutant adults at three different time points in their life cycle: one from 3–5 day-old flies, from 15–20 and from 27–30 days. The results obtained were compared with the same age-groups of wild type flies. We found that mutant adults showed a decrease in the olfactory response to 1-hexanol, α-pinene and essential oil volatiles. This olfactory response in mutant adults decreased even more as the flies aged. Immunohistological analysis of the antennal lobes in these mutants revealed structural abnormalities, especially in the expression of Bruchpilot protein, a marker for synaptic active zones. The combination of electrophysiological and morphological results suggests that the altered synaptic organization may be due to a neurodegenerative process. Our results indicate that this model can be used as a tool for understanding PD pathogensis and pathophysiology. These results help to explore the potential of using olfaction as a means of monitoring PD progression and developing new treatments. [ABSTRACT FROM AUTHOR]

In this paper, we describe the effects of the combination of topographical, mechanical, chemical and intracellular electrical stimuli on a co-culture of fibroblasts and skeletal muscle cells. The co-culture was anisotropically grown onto an engineered micro-grooved (10 µm-wide grooves) polyacrylamide substrate, showing a precisely tuned Young’s modulus (∼ 14 kPa) and a small thickness (∼ 12 µm). We enhanced the co-culture properties through intracellular stimulation produced by piezoelectric nanostructures (i.e., boron nitride nanotubes) activated by ultrasounds, thus exploiting the ability of boron nitride nanotubes to convert outer mechanical waves (such as ultrasounds) in intracellular electrical stimuli, by exploiting the direct piezoelectric effect. We demonstrated that nanotubes were internalized by muscle cells and localized in both early and late endosomes, while they were not internalized by the underneath fibroblast layer. Muscle cell differentiation benefited from the synergic combination of topographical, mechanical, chemical and nanoparticle-based stimuli, showing good myotube development and alignment towards a preferential direction, as well as high expression of genes encoding key proteins for muscle contraction (i.e., actin and myosin). We also clarified the possible role of fibroblasts in this process, highlighting their response to the above mentioned physical stimuli in terms of gene expression and cytokine production. Finally, calcium imaging-based experiments demonstrated a higher functionality of the stimulated co-cultures. [ABSTRACT FROM AUTHOR]

The spermatozoa of two species of Macrodasyida (Gastrotricha), Urodasys anorektoxys and U. acanthostylis, show an ultrastructural organization diverging from one another and from other gastrotrichs: their main peculiarity is in the absence of mitochondria. In U. anorektoxys, the acrosome is a long, twisted column inserted into the nucleus, which is basally cylindrical, and the flagellum shows rows of peculiar, large globules parallel to the axonemal doublets. In U. acanthostylis, the acrosome is completely cork-screwed and surrounds the nucleus, and the tail shows columnar accessory fibers. At present, the absence of mitochondria in the mature sperm, and the peculiar fingerprint aspect of condensed chromatin are the only traits shared by the two species. The features of the spermatozoa of these two species of Urodasys widen the range of different models of gastrotrich spermatozoa, and place the genus in a peculiar position, from the spermatological point of view, within the Macrodasyida. The loss of mitochondria in mature spermatozoa is possibly related to either the dysoxic habitat of the two species or a peculiar fertilization mechanism. [ABSTRACT FROM AUTHOR]

Chemokine-induced chemotaxis mediates physiological and pathological immune cell trafficking, as well as several processes involving cell migration. Among them, the role of CXCL12/CXCR4 signaling in cancer and metastasis is well known, and CXCR4 has been often targeted with small molecule-antagonists or short CXCL12-derived peptides to limit the pathological processes of cell migration and invasion. To reduce CXCR4-mediated chemotaxis, we adopted a different approach. We manufactured poly(lactic acid-co-glycolic acid) (PLGA)/Pluronic F127 nanoparticles through microfluidics-assisted nanoprecipitation and functionalized them with streptavidin to docking a biotinylated CXCL12 to be exposed on the nanoparticle surface. Our results show that CXCL12-decorated nanoparticles are non-toxic and do not induce inflammatory cytokine release in THP-1 monocytes cultured in fetal bovine and human serum-supplemented media. The cell internalization of our chemokine receptor-targeting particles increases in accordance with CXCR4 expression in FBS/medium. We demonstrated that CXCL12-decorated nanoparticles do not induce cell migration on their own, but their pre-incubation with THP-1 significantly decreases CXCR4+-cell migration, thereby antagonizing the chemotactic action of CXCL12. The use of biodegradable and immune-compatible chemokine-mimetic nanoparticles to reduce cell migration opens the way to novel antagonists with potential application in cancer treatments and inflammation. [ABSTRACT FROM AUTHOR]

A method for the aqueous synthesis of stable and biocompatible citrate-coated palladium nanoparticles (PdNPs) in the size range comparable to natural enzymes (4–8 nm) has been developed. The toxicological profile of PdNPs was assessed by different assays on several cell lines demonstrating their safety in vitro also at high particle concentrations. To elucidate their cellular fate upon uptake, the localization of PdNPs was analyzed by Transmission Electron Microscopy (TEM). Moreover, crucial information about their intracellular stability and oxidation state was obtained by Sputtering-Enabled Intracellular X-ray Photoelectron Spectroscopy (SEI-XPS). TEM/XPS results showed significant stability of PdNPs in the cellular environment, an important feature for their biocompatibility and potential for biomedical applications. On the catalytic side, these PdNPs exhibited strong and broad antioxidant activities, being able to mimic the three main antioxidant cellular enzymes, i.e., peroxidase, catalase, and superoxide dismutase. Remarkably, using an experimental model of a human oxidative stress-related disease, we demonstrated the effectiveness of PdNPs as antioxidant nanozymes within the cellular environment, showing that they are able to completely re-establish the physiological Reactive Oxygen Species (ROS) levels in highly compromised intracellular redox conditions. [ABSTRACT FROM AUTHOR]

Although conceptually obvious, the effective delivery of proteins in therapeutic applications is far from being a routine practice. The major limitation is the conservation of protein physicochemical identity during the transport to the target site. In this regard, nanoparticle-based systems offer new intriguing possibilities, provided that (i) the harsh and denaturating conditions typically used for nanoparticle synthesis are avoided or mitigated; and (ii) nanoparticle biocompatibility and degradation (for protein release) are optimized. Here, we tackle these issues by starting from a nanoparticle architecture already tested for small chemical compounds. In particular, silica-shielded liposomes are produced and loaded with a test protein (i.e., Green Fluorescent Protein) in an aqueous environment. We demonstrate promising results concerning protein encapsulation, protection during intracellular trafficking and final release triggered by nanoparticle degradations in acidic organelles. We believe this proof of principle may open new applications and developments for targeted and efficient protein delivery. [ABSTRACT FROM AUTHOR]

Summary Monoaminergic modulation of cortical and thalamic inputs to the dorsal striatum (DS) is crucial for reward-based learning and action control. While dopamine has been extensively investigated in this context, the synaptic effects of serotonin (5-HT) have been largely unexplored. Here, we investigated how serotonergic signaling affects associative plasticity at glutamatergic synapses on the striatal projection neurons of the direct pathway (dSPNs). Combining chemogenetic and optogenetic approaches reveals that impeding serotonergic signaling preferentially gates spike-timing-dependent long-term depression (t-LTD) at thalamostriatal synapses. This t-LTD requires dampened activity of the 5-HT4 receptor subtype, which we demonstrate controls dendritic Ca 2+ signals by regulating BK channel activity, and which preferentially localizes at the dendritic shaft. The synaptic effects of 5-HT signaling at thalamostriatal inputs provide insights into how changes in serotonergic levels associated with behavioral states or pathology affect striatal-dependent processes. [ABSTRACT FROM AUTHOR]

As demonstrated by F. Meinardi, L. Beverina, and co‐workers with 3T3 cells under a standard aerated environment on page 8447, sensitized triplettriplet annihilation based photon up‐conversion greatly improves the scope and applicability of fluorescence bioimaging. Anti‐Stokes detection at low powers eliminates background autofluorescence and limits the potential damage of for living tissues. [ABSTRACT FROM AUTHOR]