Glioblastoma Margin as a Diffusion Barrier Revealed by Photoactivation of Plasmonic Nanovesicles.

Glioblastoma (GBM) is the most complex and lethal primary brain cancer. Adequate drug diffusion and penetration are essential for treating GBM, but how the spatial heterogeneity in GBM impacts drug diffusion and transport is poorly understood. Herein, we report a new method, photoactivation of plasmonic nanovesicles (PANO), to measure molecular diffusion in the extracellular space of GBM. By examining three genetically engineered GBM mouse models that recapitulate key clinical features including the angiogenic core and diffuse infiltration, we found that the tumor margin has the lowest diffusion coefficient (highest tortuosity) compared with the tumor core and surrounding brain tissue. Analysis of the cellular composition shows that tortuosity in the GBM is strongly correlated with neuronal loss and astrocyte activation. Our all-optical measurement reveals the heterogeneous GBM microenvironment and highlights the tumor margin as a diffusion barrier for drug transport in the brain, with implications for therapeutic delivery.

Current Status and Future Strategies for Advancing Functional Circuit Mapping In Vivo.

The human brain represents one of the most complex biological systems, containing billions of neurons interconnected through trillions of synapses. Inherent to the brain is a biochemical complexity involving ions, signaling molecules, and peptides that regulate neuronal activity and allow for short- and long-term adaptations. Large-scale and noninvasive imaging techniques, such as fMRI and EEG, have highlighted brain regions involved in specific functions and visualized connections between different brain areas. A major shortcoming, however, is the need for more information on specific cell types and neurotransmitters involved, as well as poor spatial and temporal resolution. Recent technologies have been advanced for neuronal circuit mapping and implemented in behaving model organisms to address this. Here, we highlight strategies for targeting specific neuronal subtypes, identifying, and releasing signaling molecules, controlling gene expression, and monitoring neuronal circuits in real-time in vivo Combined, these approaches allow us to establish direct causal links from genes and molecules to the systems level and ultimately to cognitive processes.

Preparation of valine-curcumin conjugate and its in vitro antibacterial and antitumor activity and in vivo biological effects on American eels (Anguilla rostrata).

Curcumin (Cur) exhibits diverse natural pharmacological activities, despite its limited water solubility (hydrophobicity) and low bioavailability. In this investigation, a valine-curcumin conjugate (Val-Cur) was synthesized through amino acid side chain modification, and its solubility increased to 1.78 mg/mL. In vitro experimental findings demonstrated that the antibacterial activity of Val-Cur against Escherichia coli, Staphylococcus aureus, Aeromonas hydrophila, and Vibrio parahaemolyticus was significantly superior to that of Cur. The inhibition rate of Val-Cur against HepG2 (human hepatocellular carcinoma) cells was higher than that of Cur at low concentrations (below 25 µmol/L), although the IC50 value of Val-Cur did not differ significantly from that of Cur. In vivo biological effects of Val-Cur were assessed by adding it into the feed (150 mg/kg) of American eels (Anguilla rostrata). Val-Cur significantly improved the growth performance (↑weight gain rate, ↑specific growth rate, and ↓feed conversion rate) and activities of intestinal digestive enzymes (amylase and lipase) and antioxidant enzymes (superoxide dismutase) in American eels. Additionally, Val-Cur significantly improved serum biochemical indices (↑high-density lipoprotein cholesterol, ↓low-density lipoprotein cholesterol, ↓aspartate and alanine aminotransferases). Furthermore, Val-Cur increased intestinal microbial diversity, reduced the abundance of potentially pathogenic bacteria (Spiroplasma, Clostridium, and Pseudomonas), and elevated the abundance of beneficial digestion-promoting bacteria (Romboutsia, Phyllobacterium, Romboutsia sedimentorum, and Clostridium butyricum) conducive to glucose metabolism (P < 0.05). To the best of our knowledge, this study is the first to explore water-soluble curcumin in aquaculture, and the findings will lay the groundwork for the potential application of water-soluble curcumin in the field of aquaculture.

Selenium nanoparticles coated with polysaccharide-protein complexes from abalone viscera improve growth and enhance resistance to diseases and hypoxic stress in juvenile Nile tilapia (Oreochromis niloticus).

The use of selenium nanoparticles (SeNPs) in aquaculture has been increasing gradually over the past few years. SeNPs enhance immunity, are highly effective against pathogens, and have low toxicity. In this study, SeNPs were prepared using polysaccharide-protein complexes (PSP) from abalone viscera. The acute toxicity of PSP-SeNPs to juvenile Nile tilapia and their effect on growth performance, intestinal tissue structure, antioxidation capacity, hypoxic stress, and Streptococcus agalactiae infection were investigated. The results showed that the spherical PSP-SeNPs were stable and safe, with an LC50 of 13.645 mg/L against tilapia, which was about 13-fold higher than that of sodium selenite (Na2SeO3). A basal diet supplemented with 0.1-1.5 mg/kg PSP-SeNPs improved the growth performance of tilapia juveniles to a certain extent, increased the intestinal villus length, and significantly enhanced the activities of liver antioxidant enzymes, including superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), and catalase (CAT). PSP-SeNPs also enhanced the resistance of tilapia to hypoxic stress and Streptococcus agalactiae infection, with supplementation at 0.1-0.3 mg/kg exerting more obvious effects than 1.5 mg/kg. However, PSP-SeNPs at a concentration of 4.5 mg/kg and Na2SeO3 at 0.3 mg/kg negatively affected the growth, gut health, and the activity of the antioxidant enzymes of tilapia. Quadric polynomial regression analysis revealed that 0.1-1.2 mg/kg was the optimal PSP-SeNP supplementation concentration for tilapia feeds. The findings of this study lay a foundation for the application of PSP-SeNPs in aquaculture.

Reversibly Modulating the Blood-Brain Barrier by Laser Stimulation of Molecular-Targeted Nanoparticles.

The blood-brain barrier (BBB) is highly selective and acts as the interface between the central nervous system and circulation. While the BBB is critical for maintaining brain homeostasis, it represents a formidable challenge for drug delivery. Here we synthesized gold nanoparticles (AuNPs) for targeting the tight junction specifically and demonstrated that transcranial picosecond laser stimulation of these AuNPs post intravenous injection increases the BBB permeability. The BBB permeability change can be graded by laser intensity, is entirely reversible, and involves increased paracellular diffusion. BBB modulation does not lead to significant disruption in the spontaneous vasomotion or the structure of the neurovascular unit. This strategy allows the entry of immunoglobulins and viral gene therapy vectors, as well as cargo-laden liposomes. We anticipate this nanotechnology to be useful for tissue regions that are accessible to light or fiberoptic application and to open new avenues for drug screening and therapeutic interventions in the central nervous system.

Probing Neuropeptide Volume Transmission In Vivo by Simultaneous Near-Infrared Light-Triggered Release and Optical Sensing.

Neuropeptides are abundant signaling molecules in the central nervous system. Yet remarkably little is known about their spatiotemporal spread and biological activity. Here, we developed an integrated optical approach using Plasmonic nAnovesicles and cell-based neurotransmitter fluorescent engineered reporter (CNiFER), or PACE, to probe neuropeptide signaling in the mouse neocortex. Small volumes (fL to pL) of exogenously supplied somatostatin-14 (SST) can be rapidly released under near-infrared light stimulation from nanovesicles implanted in the brain and detected by SST2 CNiFERs with nM sensitivity. Our measurements reveal reduced but synchronized SST transmission within 130 µm, and markedly smaller and delayed transmission at longer distances. These measurements enabled a quantitative estimation of the SST loss rate due to peptide degradation and binding. PACE offers a new tool for determining the spatiotemporal scales of neuropeptide volume transmission and signaling in the brain.

Preparation and growth-promoting effect of selenium nanoparticles capped by polysaccharide-protein complexes on tilapia.

BACKGROUND: Compared with traditional inorganic and organic selenium compounds, nano-selenium exhibited higher biological safety and nutritional potency. However, the biological efficacy of nano-selenium has not been comprehensively and accurately evaluated due to its dispersion instability. RESULTS: In this study, novel selenium nanoparticles (SeNPs) with high dispersion stability were successfully prepared using a polysaccharide-protein complex (PSP) as the capping agent. This was isolated from abalone viscera. The average particle size and zeta potential of polysaccharide-protein complex selenium nanoparticles (PSP-SeNPs) were 63.33 nm, and -37.1 mV, respectively. The SeNPs were firmly capped by PSP through SeO and SeN bonds, as demonstrated by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and transmission electron microscopy. Due to this capping, the dispersion of PSP-SeNPs remained stable for 12 months at 4 °C, as evidenced by visual inspection and multiple light scattering. Furthermore, PSP-SeNPs imparted an excellent growth-promoting effect on tilapia. The FBW, WGR, and SGR values of tilapia juveniles fed with PSP-SeNPs supplemented diets (0.5-4.5 mg/kg) were significantly higher than those of the control (P < 0.05). A weight gain rate of 4.1%-43.4% and specific growth rate of 0.15%-1.74% were obtained in tilapia during 45-day feeding. CONCLUSIONS: The use of marine viscera polysaccharides is a promising, green method for the synthesis of selenium nanoparticles. There are good opportunities for the application of the synthesized PSP-SeNPs in the life sciences. © 2020 Society of Chemical Industry.

Near-Infrared Light Triggered-Release in Deep Brain Regions Using Ultra-photosensitive Nanovesicles.

Remote and minimally-invasive modulation of biological systems with light has transformed modern biology and neuroscience. However, light absorption and scattering significantly prevents penetration to deep brain regions. Herein, we describe the use of gold-coated mechanoresponsive nanovesicles, which consist of liposomes made from the artificial phospholipid Rad-PC-Rad as a tool for the delivery of bioactive molecules into brain tissue. Near-infrared picosecond laser pulses activated the gold-coating on the surface of nanovesicles, creating nanomechanical stress and leading to near-complete vesicle cargo release in sub-seconds. Compared to natural phospholipid liposomes, the photo-release was possible at 40 times lower laser energy. This high photosensitivity enables photorelease of molecules down to a depth of 4 mm in mouse brain. This promising tool provides a versatile platform to optically release functional molecules to modulate brain circuits.

Amphiphilic Polycarbonates from Carborane-Installed Cyclic Carbonates as Potential Agents for Boron Neutron Capture Therapy.

Carboranes with rich boron content have showed significant applications in the field of boron neutron capture therapy. Biodegradable derivatives of carborane-conjugated polymers with well-defined structure and tunable loading of boron atoms are far less explored. Herein, a new family of amphiphilic carborane-conjugated polycarbonates was synthesized by ring-opening polymerization of a carborane-installed cyclic carbonate monomer. Catalyzed by TBD from a poly(ethylene glycol) macroinitiator, the polymerization proceeded to relatively high conversions (>65%), with low polydispersity in a certain range of molecular weight. The boron content was readily tuned by the feed ratio of the monomer and initiator. The resultant amphiphilic polycarbonates self-assembled in water into spherical nanoparticles of different sizes depending on the hydrophilic-to-hydrophobic ratio. It was demonstrated that larger nanoparticles (PN150) were more easily subjected to protein adsorption and captured by the liver, and smaller nanoparticles (PN50) were more likely to enter cancer cells and accumulate at the tumor site. PN50 with thermal neutron irradiation exhibited the highest therapeutic efficacy in vivo. The new synthetic method utilizing amphiphilic biodegradable boron-enriched polymers is useful for developing more-selective and -effective boron delivery systems for BNCT.

Doxorubicin-Loaded Carborane-Conjugated Polymeric Nanoparticles as Delivery System for Combination Cancer Therapy.

Carborane-conjugated amphiphilic copolymer nanoparticles were designed to deliver anticancer drugs for the combination of chemotherapy and boron neutron capture therapy (BNCT). Poly(ethylene glycol)-b-poly(L-lactide-co-2-methyl-2(2-dicarba-closo-dodecarborane)propyloxycarbonyl-propyne carbonate) (PLMB) was synthesized via the versatile reaction between decaborane and side alkynyl groups, and self-assembled with doxorubicin (DOX) to form drug-loaded nanoparticles. These DOX@PLMB nanoparticles could not only suppress the leakage of the boron compounds into the bloodstream due to the covalent bonds between carborane and polymer main chains, but also protect DOX from initial burst release at physiological conditions because of the dihydrogen bonds between DOX and carborane. It was demonstrated that DOX@PLMB nanoparticles could selectively deliver boron atoms and DOX to the tumor site simultaneously in vivo. Under the combination of chemotherapy and BNCT, the highest tumor suppression efficiency without reduction of body weight was achieved. This polymeric nanoparticles delivery system could be very useful in future chemoradiotherapy to obtain improved therapeutic effect with reduced systemic toxicity.

Recent advances in stimuli-responsive controlled release systems for neuromodulation.

Neuromodulation aims to modulate the signaling activity of neurons or neural networks by the precise delivery of electrical stimuli or chemical agents and is crucial for understanding brain function and treating brain disorders. Conventional approaches, such as direct physical stimulation through electrical or acoustic methods, confront challenges stemming from their invasive nature, dependency on wired power sources, and unstable therapeutic outcomes. The emergence of stimulus-responsive delivery systems harbors the potential to revolutionize neuromodulation strategies through the precise and controlled release of neurochemicals in a specific brain region. This review comprehensively examines the biological barriers controlled release systems may encounter in vivo and the recent advances and applications of these systems in neuromodulation. We elucidate the intricate interplay between the molecular structure of delivery systems and response mechanisms to furnish insights for material selection and design. Additionally, the review contemplates the prospects and challenges associated with these systems in neuromodulation. The overarching objective is to propel the application of neuromodulation technology in analyzing brain functions, treating brain disorders, and providing insightful perspectives for exploiting new systems for biomedical applications.

Bimetallic nanoparticles as cascade sensitizing amplifiers for low-dose and robust cancer radio-immunotherapy.

Radiotherapy (RT) is one of the most feasible and routinely used therapeutic modalities for treating malignant tumors. In particular, immune responses triggered by RT, known as radio-immunotherapy, can partially inhibit the growth of distantly spreading tumors and recurrent tumors. However, the safety and efficacy of radio-immunotherapy is impeded by the radio-resistance and poor immunogenicity of tumor. Herein, we report oxaliplatin (IV)-iron bimetallic nanoparticles (OXA/Fe NPs) as cascade sensitizing amplifiers for low-dose and robust radio-immunotherapy. The OXA/Fe NPs exhibit tumor-specific accumulation and activation of OXA (II) and Fe2+ in response to the reductive and acidic microenvironment within tumor cells. The cascade reactions of the released metallic drugs can sensitize RT by inducing DNA damage, increasing ROS and O2 levels, and amplifying the immunogenic cell death (ICD) effect after RT to facilitate potent immune activation. As a result, OXA/Fe NPs-based low-dose RT triggered a robust immune response and inhibited the distant and metastatic tumors effectively by a strong abscopal effect. Moreover, a long-term immunological memory effect to protect mice from tumor rechallenging is observed. Overall, the bimetallic NPs-based cascade sensitizing amplifier system offers an efficient radio-immunotherapy regimen that addresses the key challenges.

Live Mapping of the Brain Extracellular Matrix and Remodeling in Neurological Disorders.

Live imaging of the brain extracellular matrix (ECM) provides vital insights into changes that occur in neurological disorders. Current techniques such as second or third-harmonic generation offer limited contrast for live imaging of the brain ECM. Here, a new method, pan-ECM via chemical labeling of extracellular proteins, is introduced for live brain ECM imaging. pan-ECM labels all major ECM components in live tissue including the interstitial matrix, basement membrane, and perineuronal nets. pan-ECM enables in vivo observation of the ECM heterogeneity between the glioma core and margin, as well as the assessment of ECM deterioration under stroke condition, without ECM shrinkage from tissue fixation. These findings indicate that the pan-ECM approach is a novel way to image the entire brain ECM in live brain tissue with optical resolution. pan-ECM has the potential to advance the understanding of ECM in brain function and neurological diseases.

Understanding Neuropeptide Transmission in the Brain by Optical Uncaging and Release.

Neuropeptides are abundant and essential signaling molecules in the nervous system involved in modulating neural circuits and behavior. Neuropeptides are generally released extrasynaptically and signal via volume transmission through G-protein-coupled receptors (GPCR). Although substantive functional roles of neuropeptides have been discovered, many questions on neuropeptide transmission remain poorly understood, including the local diffusion and transmission properties in the brain extracellular space. To address this challenge, intensive efforts are required to develop advanced tools for releasing and detecting neuropeptides with high spatiotemporal resolution. Because of the rapid development of biosensors and materials science, emerging tools are beginning to provide a better understanding of neuropeptide transmission. In this perspective, we summarize the fundamental advances in understanding neuropeptide transmission over the past decade, highlight the tools for releasing neuropeptides with high spatiotemporal solution in the brain, and discuss open questions and future directions in the field.

Abalone visceral peptides containing Cys and Tyr exhibit strong in vitro antioxidant activity and cytoprotective effects against oxidative damage.

The in vitro antioxidation and cytoprotection of abalone visceral peptides against oxidative damage were investigated. Results show that the DPPH· scavenging activities of the 16 chemically synthesized peptides were significantly and positively correlated with their reducing power. Their scavenging activities against ABTS·+ were positively correlated with their ability to inhibit linoleic acid oxidation. Only Cys containing peptides exhibited good DPPH· scavenging activity, while only Tyr containing peptides showed significant ABTS·+ scavenging activity. In the cytoprotection assay, all four representative peptides significantly increased the viability of H2O2-damaged LO2 cells and the activities of GSH-Px, CAT, and SOD, and all decreased MDA levels and LDH leakage, in which the Cys-containing peptides were more effective at increasing the activities of antioxidant enzymes, while the Tyr-containing peptides were more effective at decreasing MDA levels and LDH leakage. Abalone visceral peptides containing both Cys and Tyr exhibit strong in vitro and cellular antioxidation.

Pomelo peel dietary fiber ameliorates alterations in obesity-related features and gut microbiota dysbiosis in mice fed on a high-fat diet.

Pomelo peel has abundance of dietary fiber and various biological activities but is often discarded as waste. This study evaluated the biological activities of pomelo peel dietary fiber (PPDF) in preventing obesity and regulating intestinal microbiota in obese mouse model induced using a high-fat diet (HFD). As for the composition, the prepared PPDF contained 89.64% of total dietary fiber, 53.27% of insoluble dietary fiber, and 36.37% of soluble dietary fiber. PPDF treatment significantly reduced weight gain and fat accumulation in the liver and epididymal tissues of obese mice; significantly alleviated HFD-induced dyslipidemia; and restored the levels of triglycerides, low-density lipoprotein-cholesterol, and high-density lipoprotein--cholesterol to control levels, and the PPDF 5% dose restored total cholesterol to the control level. Furthermore, PPDF ameliorated HFD-induced gut microbiota dysbiosis by increasing intestinal microbial diversity, decreasing the Firmicutes/Bacteroidetes ratio, increasing beneficial bacteria (Bifidobacterium, Alloprevotella, and Lactobacillus), and decreasing harmful bacteria (Staphylococcus and Corynebacterium_1). This study provided a new idea to use PPDF as functional food to prevent obesity, alleviate dyslipidemia, or a potential probiotic to ameliorate gut microbiota dysbiosis.

Response surface methodology-optimized extraction of flavonoids from pomelo peels and isolation of naringin with antioxidant activities by Sephadex LH20 gel chromatography.

In this study, flavonoids were extracted from pomelo peels and naringin was isolated from the flavonoid extract. The effects of extraction parameters, namely, ethanol concentration, solid-to-liquid ratio, and extraction time, on the yield of flavonoids extracted from pomelo peels were analyzed according to the Box-Behnken design of response surface methodology. The experimental conditions for flavonoid extraction were optimized, and naringin was separated from the extracted flavonoids using Sephadex LH-20 column chromatography. Experimental results showed that the influence of factors on the extraction rate of flavonoids from pomelo peels was in the order of ethanol concentration > solid-to-liquid ratio > extraction time, and the optimal extraction parameters were 85% ethanol concentration, 1:20 solid-to-liquid ratio, and 4-h extraction time for extracting flavonoids from pomelo peels. Under these conditions, the yield of flavonoids was 6.07 ± 0.06 mg/g. After three times of extraction, the flavonoid extraction rate reached 96.55%, and the residual naringin in the pomelo peels was 0.017 mg/g, at which point the bitterness in the pomelo peels disappeared. Two components, namely, PF1 and PF2, were separated from the crude flavonoid of pomelo peels through Sephadex LH20 column chromatography. PF2 was identified as naringin by high-performance liquid chromatography tandem mass spectrometry, with a purity of 95.7 ± 0.23%. Both flavonoids and PF2 exhibited good in vitro radicals scavenging activities on DPPH, ABTS, superoxide anion and hydroxyl.

pan-ECM: live brain extracellular matrix imaging with protein-reactive dye.

The brain extracellular matrix (ECM), consisting of proteins and glycosaminoglycans, is a critical scaffold in the development, homeostasis, and disorders of the central nervous system (CNS) and undergoes remodeling in response to environmental cues. Live imaging of brain ECM structure represents a native view of the brain ECM but, until now, remains challenging due to the lack of a robust fluorescent labeling approach. Here, we developed a pan-ECM method for labeling the entire (Greek: pan) brain ECM network by screening and delivering a protein-reactive dye into the brain. pan-ECM enables imaging of ECM compartments in live brain tissue, including the interstitial matrix, basement membrane (BM), and perineuronal nets (PNNs), and even the ECM in glioblastoma and stroke mouse brains. This approach provides access to the structure and dynamics of the ECM and enhances our understanding of the complexities of the brain ECM and its contribution to brain health and disease.

Combination of IDO inhibitors and platinum(IV) prodrugs reverses low immune responses to enhance cancer chemotherapy and immunotherapy for osteosarcoma.

In recent years, immune checkpoint blockades (ICBs) have made great progress in the treatment of cancer. However, most ICBs have not yet been observed to be satisfactory in the treatment of osteosarcoma. Herein, we designed composite nanoparticles (NP-Pt-IDOi) from a reactive oxygen species (ROS) sensitive amphiphilic polymer (PHPM) with thiol-ketal bonds in the main chain to encapsulate a Pt(IV) prodrug (Pt(IV)-C12) and an indoleamine-(2/3)-dioxygenase (IDO) inhibitor (IDOi, NLG919). Once NP-Pt-IDOi enter the cancer cells, the polymeric nanoparticles could dissociate due to the intracellular ROS, and release Pt(IV)-C12 and NLG919. Pt(IV)-C12 induces DNA damage and activates the cGAS-STING pathway, increasing infiltration of CD8+ T cells in the tumor microenvironment. In addition, NLG919 inhibits tryptophan metabolism and enhances CD8+ T cell activity, ultimately activating anti-tumor immunity and enhancing the anti-tumor effects of platinum-based drugs. NP-Pt-IDOi were shown to have superior anti-cancer activity in vitro and in vivo in mouse models of osteosarcoma, providing a new clinical paradigm for combining chemotherapy with immunotherapy for osteosarcoma.

Glioblastoma Margin as a Diffusion Barrier Revealed by Photoactivation of Plasmonic Nanovesicles.

Glioblastoma (GBM) is the most complex and lethal adult primary brain cancer. Adequate drug diffusion and penetration are essential for treating GBM, but how the spatial heterogeneity in GBM impacts drug diffusion and transport is poorly understood. Herein, we report a new method, photoactivation of plasmonic nanovesicles (PANO), to measure molecular diffusion in the extracellular space of GBM. By examining three genetically engineered GBM mouse models that recapitulate key clinical features including angiogenic core and diffuse infiltration, we found that the tumor margin has the lowest diffusion coefficient (highest tortuosity) compared with the tumor core and surrounding brain tissue. Analysis of the cellular composition shows that the tortuosity in the GBM is strongly correlated with neuronal loss and astrocyte activation. Our all-optical measurement reveals the heterogeneous GBM microenvironment and highlights the tumor margin as a diffusion barrier for drug transport in the brain, with implications for therapeutic delivery.