Gabapentin improves neuropathic pain in Minamata disease model rats.

BACKGROUND: Methylmercury (MeHg), the causative agent of Minamata disease, damages the cranial nervous system and causes specific sensory disturbances, especially hypoesthesia, in the extremities. However, recent reports demonstrate that patients with chronic Minamata disease conversely develop neuropathic pain in the lower extremities. Studies on our established Minamata disease model rats showed that MeHg-mediated neurodegeneration might induce neuropathic pain by over time through inducing rewiring with neuronal activation in the somatosensory cortex via microglial activation in the spinal dorsal horn. METHODS: In this study, the effects of gabapentin, a potentially effective treatment for neuropathic pain, was evaluated using this Minamata disease model rats. To further elucidate the mechanism of its medicinal effects, histochemical and biochemical analyses of the nervous system of Minamata disease model rats were conducted. RESULTS: Gabapentin treatment restored the reduction in the pain threshold caused by MeHg exposure in rats. Histochemical and biochemical analyses revealed that gabapentin showed no effect on MeHg-induced neurodegeneration in entire nervous system and microglial activation in the spinal dorsal horn. However, it was shown that gabapentin may reduce excessive synaptogenesis through its antagonist action on the alpha2-delta-1 subunit of calcium channels in the somatosensory cortex. CONCLUSIONS: These results indicate that gabapentin may alleviated neuropathic pain in MeHg poisoning, as typified by Minamata disease, by reversibly modulation synaptic rewiring in the somatosensory cortex.

Application of an Antibacterial Coating Layer via Amine-Terminated Hyperbranched Zirconium-Polysiloxane for Stainless Steel Orthodontic Brackets.

The massive growth of various microorganisms on the orthodontic bracket can form plaques and cause diseases. A novel amine-terminated hyperbranched zirconium-polysiloxane (HPZP) antimicrobial coating was developed for an orthodontic stainless steel tank (SST). After synthesizing HPZP and HPZP-Ag coatings, their structures were characterized by nuclear magnetic resonance spectroscopy, scanning electron microscopy, thickness measurement, contact angle detection, mechanical stability testing, and corrosion testing. The cell toxicity of the two coatings to human gingival fibroblasts (hGFs) and human oral keratinocytes (hOKs) was detected by cell counting kit eight assays, and SST, HPZP@SST, and HPZP-Ag@SST were cocultured with Staphylococcus aureus, Escherichia coli, and Streptococcus mutans for 24 hr to detect the antibacterial properties of the coatings, respectively. The results show that the coatings are about 10 µm, and the water contact angle of HPZP coating is significantly higher than that of HPZP-Ag coating (P < 0.01). Both coatings can be uniformly and densely distributed on SST and have good mechanical stability and corrosion resistance. The cell counting test showed that HPZP coating and HPZP-Ag coating were less toxic to cells compared with SST, and the toxicity of HPZP-Ag coating was greater than that of HPZP coating, with the cell survival rate greater than 80% after 72 hr cocultured with hGFs and hOKs. The antibacterial test showed that the number of bacteria on the surface of different materials was ranked from small to large: HPZP@SST < HPZP-Ag@SST < SST and 800 µg/mL HPZP@SST showed a better bactericidal ability than 400 µg/mL after cocultured with S. aureus, E. coli, and S. mutans, respectively (all P < 0.05). The results showed that HPZP coating had a better effect than HPZP-Ag coating, with effective antibacterial and biocompatible properties, which had the potential to be applied in orthodontic process management.

6-Methoxyflavone antagonizes chronic constriction injury and diabetes associated neuropathic nociception expression.

Neuropathy is a disturbance of function or a pathological change in nerves causing poor health and quality of life. A proportion of chronic pain patients in the community suffer persistent neuropathic pain symptoms because current drug therapies may be suboptimal so there is a need for new therapeutic modalities. This study investigated the neuroprotective flavonoid, 6-methoxyflavone (6MF), as a potential therapeutic agent and gabapentin as the standard comparator, against neuropathic models. Thus, neuropathic-like states were induced in Sprague-Dawley rats using sciatic nerve chronic constriction injury (CCI) mononeuropathy and systemic administration of streptozotocin (STZ) to induce polyneuropathy. Subsequent behaviors reflecting allodynia, hyperalgesia, and vulvodynia were assessed and any possible motoric side-effects were evaluated including locomotor activity, as well as rotarod discoordination and gait disruption. 6MF (25-75 mg/kg) antagonized neuropathic-like nociceptive behaviors including static- (pressure) and dynamic- (light brushing) hindpaw allodynia plus heat/cold and pressure hyperalgesia in the CCI and STZ models. 6MF also reduced static and dynamic components of vulvodynia in the STZ induced polyneuropathy model. Additionally, 6MF reversed CCI and STZ suppression of locomotor activity and rotarod discoordination, suggesting a beneficial activity on motor side effects, in contrast to gabapentin. Hence, 6MF possesses anti-neuropathic-like activity not only against different nociceptive modalities but also impairment of motoric side effects.

Functional Activity of Enantiomeric Oximes and Diastereomeric Amines and Cyano Substituents at C9 in 3-Hydroxy-N-phenethyl-5-phenylmorphans.

The synthesis of stereochemically pure oximes, amines, saturated and unsaturated cyanomethyl compounds, and methylaminomethyl compounds at the C9 position in 3-hydroxy-N-phenethyl-5-phenylmorphans provided µ-opioid receptor (MOR) agonists with varied efficacy and potency. One of the most interesting compounds, (2-((1S,5R,9R)-5-(3-hydroxyphenyl)-2-phenethyl-2-azabicyclo[3.3.1]nonan-9-yl)acetonitrile), was found to be a potent partial MOR agonist (EC50 = 2.5 nM, %Emax = 89.6%), as determined in the forskolin-induced cAMP accumulation assay. Others ranged in potency and efficacy at the MOR, from nanomolar potency with a C9 cyanomethyl compound (EC50 = 0.85 nM) to its totally inactive diastereomer, and three compounds exhibited weak MOR antagonist activity (the primary amine 3, the secondary amine 8, and the cyanomethyl compound 41). Many of the compounds were fully efficacious; their efficacy and potency were affected by both the stereochemistry of the molecule and the specific C9 substituent. Most of the MOR agonists were selective in their receptor interactions, and only a few had δ-opioid receptor (DOR) or κ-opioid receptor (KOR) agonist activity. Only one compound, a C9-methylaminomethyl-substituted phenylmorphan, was moderately potent and fully efficacious as a KOR agonist (KOR EC50 = 18 nM (% Emax = 103%)).

Effects of basic amino acids on heterocyclic amines and quality characteristics of fried beef patties at low NaCl level.

The impact of basic amino acids (Lysine, Arginine, Histidine) on the formation of total heterocyclic amines (HAs) was investigated in fried beef patties at 1% NaCl level. Different levels of basic amino acids (0.1%, 0.5%, 1%) significantly inhibited the formation of the total and individual HAs at 1% NaCl, and the inhibitory effect was more effective than 3% NaCl (6.19 ng/g, 26.93% inhibition) (P < 0.05). Lys at 1% reduced total HAs the most (2.46 ng/g, 70.88% inhibition), followed by 1% His (2.79 ng/g, 67.03% inhibition) and 1% Arg (3.43 ng/g, 59.51% inhibition). Compared to the 3% NaCl, the quality characteristics (moisture content, frying loss, texture profile, and color) of the fried beef patties were significantly improved when basic amino acids were added at 1% NaCl (P < 0.05). The lipid oxidation of fried beef patties was significantly inhibited by 1% Arg and 1% Lys at 1% NaCl level (P < 0.05). The results indicated that basic amino acids could inhibit the formation of total HAs while maintaining the quality of meat products at low NaCl condition.

Antinociceptive effects of fentanyl and nonopioid drugs in methocinnamox-treated rats.

BACKGROUND: A single administration of the opioid receptor antagonist methocinnamox (MCAM) antagonizes the antinociceptive effects of µ-opioid receptor agonists for 2 weeks or longer. Such a long duration of antagonism could necessitate the use of nonopioid drugs for treating pain in patients receiving MCAM for opioid use disorder (OUD). METHODS: The antinociceptive effects of fentanyl and nonopioid drugs were assessed in 24 male Sprague Dawley rats using a complete Freund's adjuvant (CFA) model of inflammatory pain. Twelve rats received 10mg/kg MCAM and 12 received vehicle; half (n=6) of the animals from each treatment group were treated (intraplantar) with CFA or saline. Hypersensitivity to mechanical stimulation was measured using a von Frey anesthesiometer. Fentanyl (0.01-0.1mg/kg), ketamine (17.8-56mg/kg), gabapentin (32-100mg/kg), meloxicam (3.2-10mg/kg), and ∆9-tetrahydrocannabinol (THC, 1-10mg/kg) were administered intraperitoneally and tested every 3 days in a pseudorandom order. Next, the same drugs were studied for effects on motor performance using a rotarod apparatus. RESULTS: CFA-induced hypersensitivity was attenuated by fentanyl in vehicle- but not MCAM-treated rats. THC, ketamine, and gabapentin attenuated (up to 82, 66, and 46 %, respectively) CFA-evoked mechanical hypersensitivity in both MCAM- and vehicle-treated rats. Meloxicam failed to alter CFA-evoked mechanical hypersensitivity in either group. Fentanyl, THC, gabapentin, and meloxicam did not affect motor performance in either group whereas ketamine impaired motor performance in both groups (up to 71 % reduction in latency to fall). CONCLUSIONS: These data suggest that ketamine, gabapentin, and THC could be effective for treating inflammatory pain under conditions of long term µ-opioid receptor antagonism.

Discovery of Novel Cholinesterase Inhibitors Easily Crossing the Blood-Brain Barrier via Structure-Property Relationship Investigation: Methylenedioxy-Cinnamicamide Containing Tertiary Amine Side Chain.

In the present investigation, a series of dimethoxy or methylenedioxy substituted-cinnamamide derivatives containing tertiary amine moiety (N. N-Dimethyl, N, N-diethyl, Pyrrolidine, Piperidine, Morpholine) were synthesized and evaluated for cholinesterase inhibition and blood-brain barrier (BBB) permeability. Although their chemical structures are similar, their biological activities exhibit diversity. The results showed that all compounds except for those containing morpholine group exhibited moderate to potent acetylcholinesterase inhibition. Preliminary screening of BBB permeability shows that methylenedioxy substituted compounds have better brain permeability than the others. Compound 10c, containing methylenedioxy and pyrrolidine side chain, showed a better acetylcholinesterase inhibition (IC50: 1.52±0.19 µmol/L) and good blood-brain barrier permeability. Further pharmacokinetic investigation of compound 10c using ultra high performance liquid chromatography-mass/mass spectrometry (UPLC-MS/MS) in mice showed that compound 10c in brain tissue reached its peak concentration (857.72±93.56 ng/g) after dosing 30 min. Its half-life in the serum is 331 min (5.52 h), and the CBrain/CSerum at various sampling points is ranged from 1.65 to 4.71(Mean: 2.76) within 24 hours. This investigation provides valuable information on the chemistry and pharmacological diversity of cinnamic acid derivatives and may be beneficial for the discovery of central nervous system drugs.

N-Functionalization of ß-aminophosphonates: cytotoxic effects of the new derivatives.

ß-Aminophosphonates obtained by the Michael addition of primary amines to the double bond of diethyl vinylphosphonate proved to be suitable starting materials (amine components) in the Kabachnik-Fields reaction with formaldehyde and dialkyl phosphites or secondary phosphine oxides to afford N-phosphonylmethyl- and N-phosphinoylmethyl-ß-aminophosphonates. On the other hand, the starting aminophosphonates were modified by N-acylation using acid chlorides. The N-acyl products were found to exist in a dynamic equilibrium of two conformers as suggested by the broad NMR signals. At 26 °C, there may be rotation around the N-C axis of the acylamide function. At the same time, low-temperature NMR measurements at -5 °C revealed the presence of two distinct rotamers that could be characterized by 31P, 13C and 1H NMR data. The modified ß-aminophosphonic derivatives were subjected to a comparative structure-activity analysis on MDA-MB-231, PC-3, A431 and Ebc-1 tumor cell lines, and in a few cases, significant activity was detected.

Generalized Multifunctional Coating Strategies Based on Polyphenol-Amine-Inspired Chemistry and Layer-by-Layer Deposition for Blood Contact Catheters.

Blood-contacting catheters play a pivotal role in contemporary medical treatments, particularly in the management of cardiovascular diseases. However, these catheters exhibit inappropriate wettability and lack antimicrobial characteristics, which often lead to catheter-related infections and thrombosis. Therefore, there is an urgent need for blood contact catheters with antimicrobial and anticoagulant properties. In this study, we employed tannic acid (TA) and 3-aminopropyltriethoxysilane (APTES) to create a stable hydrophilic coating under mild conditions. Heparin (Hep) and poly(lysine) (PL) were then modified on the TA-APTES coating surface using the layer-by-layer (LBL) technique to create a superhydrophilic TA/APTES/(LBL)4 coating on silicone rubber (SR) catheters. Leveraging the superhydrophilic nature of this coating, it can be effectively applied to blood-contacting catheters to impart antibacterial, antiprotein adsorption, and anticoagulant properties. Due to Hep's anticoagulant attributes, the activated partial thromboplastin time and thrombin time tests conducted on SR/TA-APTES/(LBL)4 catheters revealed remarkable extensions of 276 and 103%, respectively, when compared to uncoated commercial SR catheters. Furthermore, the synergistic interaction between PL and TA serves to enhance the resistance of SR/TA-APTES/(LBL)4 catheters against bacterial adherence, reducing it by up to 99.9% compared to uncoated commercial SR catheters. Remarkably, the SR/TA-APTES/(LBL)4 catheter exhibits good biocompatibility with human umbilical vein endothelial cells in culture, positioning it as a promising solution to address the current challenges associated with blood-contact catheters.

Use of kersetin and fisetin flavonoids in combination with pregabalin and gabapentin in the treatment of neuropathic pain.

We purposed to explore the consequences of the use quercetin and fisetin alone and in combination with pregabalin and gabapentin, which are used in the management of neuropathic pain, and on neuropathic pain in general. The anti-allodynic effect of various doses (5, 10, and 20 mg/kg) of quercetin and fisetin, both singly and in combination with pregabalin and gabapentin, was evaluated by developing a neuropathic pain model induced by chronic constrictive nerve damage in rats. The effectiveness of these flavonoids was investigated by combining them with gabapentin (50 mg/kg) and pregabalin (15 mg/kg), choosing the effectual dose of 10 mg/kg and the dose of 5 mg/kg, which did not show significant antiallodynic effects. In groups combined with gabapentin and pregabalin, it was determined that they showed a significant antiallodynic effect compared with 50 mg/kg gabapentin and 15 mg/kg pregabalin. In conclusion, in our combination studies, it was observed that the effectiveness of gabapentin and pregabalin, was increased and the duration of effect was prolonged when used with lower doses of flavonoids. Based on these findings; it is possible to say that quercetin and fisetin are potential agents that can be used alone or in combination with other effective treatments to alleviate neuropathic pain.

N-benzyl-N-methyldecan-1-amine, derived from garlic, and its derivative alleviate 2,4-dinitrochlorobenzene-induced atopic dermatitis-like skin lesions in mice.

Given the intricate etiology and pathogenesis of atopic dermatitis (AD), the complete cure of AD remains challenging. This study aimed to investigate if topically applying N-benzyl-N-methyldecan-1-amine (BMDA), derived from garlic, and its derivative [decyl-(4-methoxy-benzyl)-methyl-1-amine] (DMMA) could effectively alleviate AD-like skin lesions in 2,4-dinitrochlorobenzene (DNCB)-treated mice. Administering these compounds to the irritated skin of DNCB-treated mice significantly reduced swelling, rash, and excoriation severity, alongside a corresponding decrease in inflamed epidermis and dermis. Moreover, they inhibited spleen and lymph node enlargement and showed fewer infiltrated mast cells in the epidermis and dermis through toluidine-blue staining. Additionally, they led to a lower IgE titer in mouse sera as determined by ELISA, compared to vehicle treatment. Analyzing skin tissue from the mice revealed decreased transcript levels of inflammatory cytokines (TNF-α, IL-1ß, and IL-6), IL-4, iNOS, and COX-2, compared to control mice. Simultaneously, the compounds impeded the activation of inflammation-related signaling molecules such as JNK, p38 MAPK, and NF-κB in the mouse skin. In summary, these findings suggest that BMDA and DMMA hold the potential to be developed as a novel treatment for healing inflammatory AD.

Tackling Severe Neutrophilic Inflammation in Airway Disorders with Functionalized Nanosheets.

Severe airway inflammatory disorders impose a significant societal burden, and the available treatments are unsatisfactory. High levels of neutrophil extracellular trap (NET) and cell-free DNA (cfDNA) were detected in the inflammatory microenvironment of these diseases, which are closely associated with persistent uncontrolled neutrophilic inflammation. Although DNase has proven to be effective in mitigating neutrophilic airway inflammation in mice by reducing cfDNA and NET levels, its clinical use is hindered by severe side effects. Here, we synthesized polyglycerol-amine (PGA) with a series of hydroxyl/amine ratios and covered them with black phosphorus (BP) nanosheets. The BP nanosheets functionalized with polyglycerol-50% amine (BP-PGA50) efficiently lowered cfDNA levels, suppressed toll-like receptor 9 (TLR9) activation and inhibited NET formation in vitro. Importantly, BP-PGA50 nanosheets demonstrated substantial accumulation in inflamed airway tissues, excellent biocompatibility, and potent inflammation modulation ability in model mice. The 2D sheet-like structure of BP-PGA50 was identified as a crucial factor for the therapeutic efficacy, and the hydroxyl/amine ratio was revealed as a significant parameter to regulate the protein resistance, cfDNA-binding efficacy, and cytotoxicity. This study shows the promise of the BP-PGA50 nanosheet for tackling uncontrolled airway inflammation, which is also significant for the treatment of other neutrophilic inflammatory diseases. In addition, our work also highlights the importance of proper surface functionalization, such as hydroxyl/amine ratio, in therapeutic nanoplatform construction for inflammation modulation.

Antiproliferative in Vitro Evaluation of Terpenic Amines Synthesized via a Rhodium-catalyzed Hydroaminomethylation.

Terpene-derived alkaloids show a variety of biological activities, including antioxidant, anti-inflammatory, antimicrobial and cytotoxicity effects. In this work, homologated monoterpene amines have been prepared via a rhodium-catalyzed hydroaminomethylation of biomass-based alkenes, such as (R)-limonene, linalool, myrcene and camphene, in combination with secondary amines of aliphatic and aromatic nature, namely morpholine and N-methylaniline, leading to highly chemo- and regioselective processes. The as-prepared amines were obtained in 50-99 % overall yields, and in vitro tested on a human colon cancer cell line (HCT-116) to evaluate their cytotoxic potential. The lead compound of the series (3 a) showed cytotoxicity in the micromolar range (IC50 52.46 µM) via the induction of cell death by apoptosis, paving the way towards further structure-activity relationship studies.

Probing the Mechanism of Action of Bis(phenolato) Amine (ONO Donor Set) Titanium(IV) Anticancer Agents.

The need for anticancer therapies that overcome metallodrug resistance while minimizing adverse toxicities is targeted, herein, using titanium coordination complexes. Octahedral titanium(IV) trans,mer-[Ti{R1N(CH2-2-MeO-4-R1-C6H2)2}2] [R1 = Et, allyl, n-Pr, CHO, F, CH2(morpholino), the latter from the formyl derivative; R2 = Me, Et; not all combinations] are attained from Mannich reactions of commercial 2-methoxyphenols (27-74% overall yield, 2 steps). These crystalline (four X-ray structures) Ti(IV)-complexes are active against MCF-7, HCT-116, HT-29, PANC-1, and MDA-MB-468 cancer cell lines (GI50 = 0.5-38 µM). Their activity and cancer selectivity (vs nontumor MRC-5 cells) typically exceeds that of cisplatin (up to 16-fold). Proteomic analysis (in MCF-7) supported by other studies (G2/M cell cycle arrest, ROS generation, γH2AX production, caspase activation, annexin positivity, western blot, and kinase screens in MCF-7 and HCT-116) suggest apoptosis elicited by more than one mechanism of action. Comparison of these data to the modes of action proposed for salan Ti(IV) complexes is made.

New Cyanostyrylcopillar[5]arene Derivative: Synthesis, Photophysical Study, Chromogenic Detection of Aliphatic Amines, and Biofilm-Antibiofilm Activity.

The synthesis, characterization, and application of a new cyanostyrylcopillar[5]arene 1 is reported. Single-crystal X-ray diffraction and other spectroscopic techniques confirm the identity of the new copillar 1. The X-ray diffraction study reveals that the copillar 1 exhibits a 1D supramolecular chain in the solid state involving π···π interactions along the crystallographic c-axis and 1D chains are further connected by interchain C-H···π interactions to establish 2D supramolecular layers within the crystallographic bc-plane. 2D supramolecular chains on further packing introduce a 3D structure with void spaces filled with hexane molecules. Through minimal deviation in the dihedral angle, the cyano-substituted ethylenic group in 1 shows a conjugation with the phenolic -OH, favoring intramolecular bond conjugation (ITBC) and colorimetrically detects the aliphatic amines over aromatic amines in CH3CN. Among the aliphatic amines, tertiary amines are differentiated from primary and secondary amines by the naked eye through color change. Both in solution and solid states, 1 displays vapor phase detection of volatile aliphatic amines. Antibacterial activity analysis shows that while 1 exhibits the antibiofilm action against Gram-positive pathogenic bacteria, Staphylococcus aureus, it promotes biofilm formation by Gram-negative pathogenic bacteria, Pseudomonas aeruginosa.

An experimental model for primary neuropathic corneal pain induced by long ciliary nerve ligation in rats.

ABSTRACT: Neuropathic corneal pain (NCP) is a new and ill-defined disease characterized by pain, discomfort, aching, burning sensation, irritation, dryness, and grittiness. However, the mechanism underlying NCP remain unclear. Here, we reported a novel rat model of primary NCP induced by long ciliary nerve (LCN) ligation. After sustained LCN ligation, the rats developed increased corneal mechanical and chemical sensitivity, spontaneous blinking, and photophobia, which were ameliorated by intraperitoneal injection of morphine or gabapentin. However, neither tear reduction nor corneal injury was observed in LCN-ligated rats. Furthermore, after LCN ligation, the rats displayed a significant reduction in corneal nerve density, as well as increased tortuosity and beading nerve ending. Long ciliary nerve ligation also notably elevated corneal responsiveness under resting or menthol-stimulated conditions. At a cellular level, we observed that LCN ligation increased calcitonin gene-related peptide (neuropeptide)-positive cells in the trigeminal ganglion (TG). At a molecular level, upregulated mRNA levels of ion channels Piezo2, TRPM8, and TRPV1, as well as inflammatory factors TNF-α, IL-1ß, and IL-6, were also detected in the TG after LCN ligation. Meanwhile, consecutive oral gabapentin attenuated LCN ligation-induced corneal hyperalgesia and increased levels of ion channels and inflammation factors in TG. This study provides a reliable primary NCP model induced by LCN ligation in rats using a simple, minimally invasive surgery technique, which may help shed light on the underlying cellular and molecular bases of NCP and aid in developing a new treatment for the disease.

Discriminative stimulus properties of two training doses of gabapentin in rats: Substitution by pregabalin, diazepam, and pentobarbital.

Gabapentin is used for the treatment of many conditions, including seizures, pain, and anxiety. Increasing reports of nonprescribed use suggest that gabapentin may elicit positive subjective effects. The present study was conducted to examine the subjective effects of gabapentin using rats trained to discriminate either a 30.0 mg/kg or 300.0 mg/kg dose of gabapentin versus vehicle on a two-choice drug discrimination task. Both doses of gabapentin were established as discriminative stimuli, and the 300.0 mg/kg dose was more readily established compared to the 30.0 mg/kg dose. Full substitution (> 80% gabapentin-lever responding) occurred by the training drug and by the gabapentinoid compound pregabalin. Partial substitution (> 20% gabapentin-lever responding) was shown by the opioid compounds morphine and fentanyl, and dose combinations of the opioid receptor antagonist naltrexone with the gabapentin training doses reduced the percentage of gabapentin-lever responding to below 80%. Partial substitution for both training doses of gabapentin occurred with the cannabinoid Δ9-tetrahydrocannabinol. The barbiturate compound pentobarbital and the benzodiazepine compound diazepam were only tested for substitution for the 300.0 mg/kg dose of gabapentin and these compounds produced full substitution. These findings demonstrate that gabapentin establishes a robust discriminative cue and exhibits stimulus effects closely similar to pregabalin, pentobarbital, and diazepam. Since pregabalin, pentobarbital, and diazepam carry a risk of problematic use and are classified as controlled substances, further evaluations of gabapentin's risks in this regard are warranted. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Radiotherapy-activated NBTXR3 nanoparticles promote ferroptosis through induction of lysosomal membrane permeabilization.

PURPOSE: Radiotherapy-activated NBTXR3 (NBTXR3 + RT) has demonstrated superior efficacy in cancer cell destruction and tumor growth control, compared to radiotherapy (RT), in preclinical and clinical settings. Previous studies highlighted the immunomodulatory properties of NBTXR3 + RT, such as modification of tumor cell immunogenicity/adjuvanticity, producing an effective local tumor control and abscopal effect, related to an enhanced antitumor immune response. Furthermore, NBTXR3 + RT has shown potential in restoring anti-PD1 efficacy in a refractory tumor model. However, the early events leading to these results, such as NBTXR3 endocytosis, intracellular trafficking and primary biological responses induced by NBTXR3 + RT remain poorly understood. METHODS: We analyzed by transmission electron microscopy endocytosis and intracellular localization of NBTXR3 nanoparticles after endocytosis in various cell lines, in vitro and in vivo. A kinetic of NBTXR3 endocytosis and its impact on lysosomes was conducted using LysoTracker staining, and a RNAseq analysis was performed. We investigated the ability of NBTXR3 + RT to induce lysosomal membrane permeabilization (LMP) and ferroptosis by analyzing lipid peroxidation. Additionally, we evaluated the recapture by cancer cells of NBTXR3 released from dead cells. RESULTS: NBTXR3 nanoparticles were rapidly internalized by cells mainly through macropinocytosis and in a less extend by clathrin-dependent endocytosis. NBTXR3-containing endosomes were then fused with lysosomes. The day following NBTXR3 addition, we measured a significant increase in LysoTracker lysosome labeling intensity, in vitro as in vivo. Following RT, a significant lysosomal membrane permeabilization (LMP) was measured exclusively in cells treated with NBTXR3 + RT, while RT had no effect. The day post-irradiation, a significant increase in lipid peroxidation, a biomarker of ferroptosis, was measured with NBTXR3 + RT compared to RT. Moreover, we demonstrated that NBTXR3 nanoparticles released from dead cells can be recaptured by cancer cells. CONCLUSIONS: Our findings provide novel insights into the early and specific biological effects induced by NBTXR3 + RT, especially LMP, not induced by RT in our models. The subsequent significant increase in lipid peroxidation partially explains the enhanced cancer cell killing capacity of NBTXR3 + RT compared to RT, potentially by promoting ferroptosis. This study improves our understanding of the cellular mechanisms underlying NBTXR3 + RT and highlights its potential as an agnostic therapeutic strategy for solid cancers treatment.

[Effect of a novel pH-responsive tertiary amine monomer dodecylmethylaminoethyl methacrylate modified resin adhesive on biofilm formation of Streptococcus mutans and Lactobacillus casei in vitro].

Objective: To explore the application prospect of a new pH-responsive tertiary amine monomer dodecylmethylaminoethyl methacrylate (DMAEM) modified resin adhesive (DMAEM@RA) in the prevention and treatment of secondary caries. Methods: Five percents DMAEM was added to the resin adhesive to synthesize DMAEM@RA for modifying. Streptococcus mutans (Sm) and Lactobacillus casei (Lc) biofilms were cultured on resin adhesive and DMAEM@RA, respectively. The culture systems were set up at pH=7.4, 6.0, 5.5, and 5.0. The antimicrobial activity of DMAEM@RA was evaluated by quantitative PCR. The effects of DMAEM@RA on biofilm thickness, bacterial amount, and extracellular polysaccharides were studied by scanning electron microscope (SEM) and extracellular polysaccharide staining. Real-time fluorescence quantitative PCR was used to study the effect of DMAEM@RA on the expression levels of cariogenic genes in Sm. Results: DMAEM@RA could significantly reduce the amount of Sm and Lc under acidic conditions, especially Lc. At pH=5.0, the logarithm value of co-cultured Sm bacteria [lg (CFU/ml)] in DMAEM@RA group (7.58±0.01) was significantly lower than that in control group (7.87±0.03) (t=14.32, P<0.001), and the logarithm value of Lc bacteria [lg (CFU/ml)] (7.29±0.04) was also significantly lower than that in control group (7.93±0.15) (t=6.93, P=0.002). SEM observed that the bacteria decreased and the cell fragments appeared in DMAEM@RA group. In addition, DMAEM@RA significantly reduced the biomass of extracellular polysaccharides in the dual-species biofilm under acidic conditions. At pH=5.0, the biomass of extracellular polysaccharides in DMAEM@RA group [(25.13±3.14) mm3/mm2] was significantly lower than that in the control group [(42.66±7.46) mm3/mm2] (t=3.75, P=0.020). DMAEM@RA could significantly up-regulate the expressions of gtfB and gtfC genes in Sm under acidic conditions. At pH=5.0, gtfB and gtfC genes were significantly up-regulated by (14.64± 0.44) times and (2.99±0.20) times, respectively (t=-42.74, P<0.001; t=-13.55, P<0.001). Conclusions: The DMAEM@RA has a good antibacterial effect under acidic conditions, demonstrating that it has a good potential to prevent the occurrence and development of secondary caries.

Age-related decline of various cognitive functions in well-experienced male rats treated with the putative anti-aging compound (2R)-1-(1-benzofuran-2-yl)-N-propylpentane-2-amine ((-)BPAP).

Aging-associated cognitive disorders lack proper medication. To meet this need translation-wise, modification of the animal models is also required. In the present study, effect of the putative anti-aging compound (2R)-1-(1-benzofuran-2-yl)-N-propylpentane-2-amine ((-)BPAP, a deprenyl derivative) on age-related cognitive decline was investigated in experienced, aged Long-Evans rats. During their lifetime, animals had acquired knowledge in various cognitive assays. Their performance in these tests was then parallel followed from the age of 27 months until their death meanwhile half of them were treated with BPAP. Cognitive performance in various tasks showed different sensitivities/resistances to age-related impairment. Pot jumping performance (motor skill-learning) started to impair first, at 21 months of age, followed by decreasing performance in five-choice serial reaction time task (attention) at 26 months. Navigation performance in Morris water maze (spatial learning) started to decline at 31 months. Performance in a cooperation task (social cognition) started to decline the latest, at 34 months. Our findings suggest that in this process, the primary factor was the level of motivation to be engaged with the task and not losing the acquired knowledge. The average lifespan of the tested rat population was 36 months. BPAP could not improve the cognitive performance; neither could it prolong lifespan. A possible reason might be that dietary restriction and lifelong cognitive engagement had beneficial effects on cognitive capabilities and lifespan creating a "ceiling effect" for further improvement. The results confirmed that experienced animals provide a translationally relevant model to study age-related cognitive decline and measure the effect of putative anti-aging compounds.