Molecular mechanisms of rapid-acting antidepressants: New perspectives for developing antidepressants.

Major depressive disorder (MDD) is a chronic relapsing psychiatric disorder. Conventional antidepressants usually require several weeks of continuous administration to exert clinically significant therapeutic effects, while about two-thirds of the patients are prone to relapse of symptoms or are completely ineffective in antidepressant treatment. The recent success of the N-methyl-D-aspartic acid (NMDA) receptor antagonist ketamine as a rapid-acting antidepressant has propelled extensive research on the action mechanism of antidepressants, especially in relation to its role in synaptic targets. Studies have revealed that the mechanism of antidepressant action of ketamine is not limited to antagonism of postsynaptic NMDA receptors or GABA interneurons. Ketamine produces powerful and rapid antidepressant effects by affecting α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptors, adenosine A1 receptors, and the L-type calcium channels, among others in the synapse. More interestingly, the 5-HT2A receptor agonist psilocybin has demonstrated potential for rapid antidepressant effects in depressed mouse models and clinical studies. This article focuses on a review of new pharmacological target studies of emerging rapid-acting antidepressant drugs such as ketamine and hallucinogens (e.g., psilocybin) and briefly discusses the possible strategies for new targets of antidepressants, with a view to shed light on the direction of future antidepressant research.

The application of extracellular vesicles in colorectal cancer metastasis and drug resistance: recent advances and trends.

Colorectal cancer (CRC) has high incidence and mortality rates and is one of the most common cancers of the digestive tract worldwide. Metastasis and drug resistance are the main causes of cancer treatment failure. Studies have recently suggested extracellular vesicles (EVs) as a novel mechanism for intercellular communication. They are vesicular particles, which are secreted and released into biological fluids, such as blood, urine, milk, etc., by a variety of cells and carry numerous biologically active molecules, including proteins, nucleic acids, lipids, metabolites, etc. EVs play a crucial part in the metastasis and drug resistance of CRC by delivering cargo to recipient cells and modulating their behavior. An in-depth exploration of EVs might facilitate a comprehensive understanding of the biological behavior of CRC metastasis and drug resistance, which might provide a basis for developing therapeutic strategies. Therefore, considering the specific biological properties of EVs, researchers have attempted to explore their potential as next-generation delivery systems. On the other hand, EVs have also been demonstrated as biomarkers for the prediction, diagnosis, and presumed prognosis of CRC. This review focuses on the role of EVs in regulating the metastasis and chemoresistance of CRC. Moreover, the clinical applications of EVs are also discussed.

α7 Nicotinic acetylcholine receptor: a key receptor in the cholinergic anti-inflammatory pathway exerting an antidepressant effect.

Depression is a common mental illness, which is related to monoamine neurotransmitters and the dysfunction of the cholinergic, immune, glutamatergic, and neuroendocrine systems. The hypothesis of monoamine neurotransmitters is one of the commonly recognized pathogenic mechanisms of depression; however, the drugs designed based on this hypothesis have not achieved good clinical results. A recent study demonstrated that depression and inflammation were strongly correlated, and the activation of alpha7 nicotinic acetylcholine receptor (α7 nAChR)-mediated cholinergic anti-inflammatory pathway (CAP) in the cholinergic system exhibited good therapeutic effects against depression. Therefore, anti-inflammation might be a potential direction for the treatment of depression. Moreover, it is also necessary to further reveal the key role of inflammation and α7 nAChR in the pathogenesis of depression. This review focused on the correlations between inflammation and depression as well-discussed the crucial role of α7 nAChR in the CAP.

Novel Curcumin Derivative-Decorated Ultralong-Circulating Paclitaxel Nanoparticles: A Novel Delivery System with Superior Anticancer Efficacy and Safety.

Purpose: Paclitaxel (PTX) has been widely utilized for the treatment of breast cancer. However, drawbacks, such as poor aqueous solubility, rapid blood clearance and severe toxicity, greatly reduce its efficacy and safety. Herein, a novel self-developed curcumin derivative (CUD) was chosen as the carrier to develop a long-acting PTX nano-delivery system (PTX-Sln@CUD) in order to improve its pharmacokinetic behavior, anti-breast cancer efficacy and safety. Methods: PTX-Sln@CUD was prepared using solid dispersion and ultrasonic technology. Relevant physical and chemical properties, including stability and release behavior, were characterized. The clearance of PTX-Sln@CUD in vivo was studied by pharmacokinetic experiments. The anti-tumor activity of PTX-Sln@CUD was investigated in vitro and in vivo. Hemolysis experiments, acute toxicity and cumulative toxicity studies were performed in mice to determine the safety of PTX-Sln@CUD. Results: The average particle size, PDI, Zeta potential, encapsulation efficiency and loading efficiency of the PTX-Sln@CUD were 238.5 ± 4.79 nm, 0.225 ± 0.011, -33.8 ± 1.26 mV, 94.20 ± 0.49% and 10.98 ± 0.31%, respectively. PTX-Sln@CUD was found to be stable at room temperature for half a year. The cumulative release rates of PTX-Sln@CUD at 24, 96 and 168 h were 17.98 ± 2.60, 57.09 ± 2.32 and 72.66 ± 4.16%, respectively, which were adherent to zero-order kinetics. T1/2, MRT (0-t) and AUC (0-t) of the PTX-Sln@CUD group were 4.03-fold (44.293 h), 7.78-fold (38.444 h) and 6.18-fold (14.716 mg/L*h) of the PTX group, respectively. PTX-Sln@CUD group demonstrated stronger anti-breast cancer activity than the PTX group. Importantly, the PTX-Sln@CUD group was safer compared to the PTX group both in vitro and in vivo. Conclusion: PTX-Sln@CUD was verified as promising therapeutic nanoparticles for breast cancer and provided a novel strategy to solve the problem of low efficacy and poor safety of clinical chemotherapy drugs.

Formulation of the novel structure curcumin derivative-loaded solid lipid nanoparticles: synthesis, optimization, characterization and anti-tumor activity screening in vitro.

This study investigated the effect of structural modification of Curcumin (CU) combined with the solid lipid nanoparticles (SLN) drug delivery system on anti-tumor activity in vitro. A new structure of Curcumin derivative (CU1) was successfully synthesized by modifying the phenolic hydroxyl group of CU. CU1 was two times more stable than CU at 45 °C or constant light. The SLN containing CU1 (CU1-SLN) was prepared, and the particle size, polydispersity index, entrapment efficiency, drug loading, and zeta potential of CU1-SLN were (104.1 ± 2.43) nm, 0.22 ± 0.008, (95.1 ± 0.38) %, (4.28 ± 0.02) %, and (28.3 ± 1.60) mV, respectively. X-ray diffraction (XRD) and Differential scanning calorimetry (DSC) showed that CU1 is amorphous in SLN. CU1-SLN released the drug slowly for 48 h, while CU and CU1 were released rapidly within 8 h. In terms of cytotoxicity, CU1 exhibited a 1.5-fold higher inhibition than CU against A549 and SMMC-7721 cells, while CU1-SLN showed 2-fold higher inhibition than CU1. Both CU1 and CU1-SLN reduced the toxicity in normal hepatocytes compared with CU (2.6-fold and 12.9-fold, respectively). CU1-SLN showed a significant apoptotic effect (p < 0.05). In summary, CU1 retained the inhibitory effect of CU against tumor cells, while improving stability and safety. Additionally, CU1-SLN presents a promising strategy for the treatment of liver and lung cancer.

Patient-Derived Xenograft: A More Standard "Avatar" Model in Preclinical Studies of Gastric Cancer.

Despite advances in diagnosis and treatment, gastric cancer remains the third most common cause of cancer-related death in humans. The establishment of relevant animal models of gastric cancer is critical for further research. Due to the complexity of the tumor microenvironment and the genetic heterogeneity of gastric cancer, the commonly used preclinical animal models fail to adequately represent clinically relevant models of gastric cancer. However, patient-derived models are able to replicate as much of the original inter-tumoral and intra-tumoral heterogeneity of gastric cancer as possible, reflecting the cellular interactions of the tumor microenvironment. In addition to implanting patient tissues or primary cells into immunodeficient mouse hosts for culture, the advent of alternative hosts such as humanized mouse hosts, zebrafish hosts, and in vitro culture modalities has also facilitated the advancement of gastric cancer research. This review highlights the current status, characteristics, interfering factors, and applications of patient-derived models that have emerged as more valuable preclinical tools for studying the progression and metastasis of gastric cancer.

Anti-lung cancer effect of paclitaxel solid lipid nanoparticles delivery system with curcumin as co-loading partner in vitro and in vivo.

The main aim of this study was to improve the therapeutic potential of a paclitaxel (PTX) and curcumin (CU) combination regimen using solid lipid nanoparticles (SLNs). PTX and CU were successfully co-encapsulated at a predetermined ratio in SLNs (PC-SLNs) with high encapsulation efficiency (CU: 97.6%, PTX: 95.8%), appropriate particle size (121.8 ± 1.69 nm), small PDI (0.267 ± 0.023), and negative zeta potential (-30.4 ± 1.25 mV). Compared with PTX or the combination of CU and PTX (CU + PTX), PC-SLNs can greatly reduce the dose of PTX while still achieving the same therapeutic effect on four cancer cell lines, among which the inhibitory effect on A549 lung cancer cells was the strongest. PC-SLNs improved the area under the curve (CU: 1.40-fold; PTX: 2.88-fold), prolonged the residence time (CU: 6.94-fold; PTX: 2.51-fold), and increased the half-life (CU: 5.62-fold; PTX: 6.46-fold), achieving long circulation. PC-SLNs were used to treat lung cancer in a nude mouse xenograft tumor model and the tumor suppression rate reached 78.42%, while those of PTX and (CU + PTX) were 40.53% and 51.56%, respectively. As PC-SLNs can prevent P-glycoprotein efflux, reverse MDR and downregulate the NF-κB pathway. PC-SLNs are a potential antineoplastic agent that is more effective and less toxic in treating lung cancer.

The Effects of a Novel Curcumin Derivative Loaded Long-Circulating Solid Lipid Nanoparticle on the MHCC-97H Liver Cancer Cells and Pharmacokinetic Behavior.

Purpose: The objective of this study was to develop long-circulating solid lipid nanoparticles (LSLN) containing a novel curcumin (CU) derivative (CU1), to improve CU1's pharmacokinetic behavior and its anti-cancer effects in MHCC-97H liver cancer cells. Methods: LSLN loaded with CU1 (CU1-LSLN) was optimized and characterized. The cell biological properties and the anti-cancer mechanism of CU1-LSLN on MHCC-97H cells were evaluated by MTT, flow cytometry, Transwell, and Western blot. CU1-LSLN was further evaluated for pharmacokinetic behavior, biodistribution, and liver toxicity in SD rats. Results: The optimized CU1-LSLN formulation showed the ideal particle size (PS), polydispersity index (PDI), zeta potential (ZP), encapsulation efficiency (EE%), and drug loading (DL%) of 122.10 ± 6.63 nm, 0.19 ± 0.02, -36.30 ± 1.25 mV, 94.98 ± 0.90% and 4.53 ± 0.69%, respectively. X-ray powder diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform infrared spectrometry (FTIR) indicated that CU1 was well encapsulated by LSLN and existed in amorphous form. Storage stability of CU1-LSLN was up to 180 days with a sustained-release of drug over 96 h. The uptake efficiency of CU1-LSLN to MHCC-97H cells was 3.24 and 2.98 times higher than that of CU and CU1 after treatment for 3 h, which helped to enhance the inhibitive effect of CU1-LSLN on the proliferation, migration, and invasion potential of MHCC-97H cells and increased its ability to promote apoptosis. Meanwhile, the expression levels of NF-κB, COX-2, MMP-2, MMP-9, and uPA decreased significantly. In vivo, CU1-LSLN prolonged the retention time of the drug, the area under the curve (AUC) increased significantly (CU: 69.9-fold, CU1: 85.9-fold), and no significant liver toxicity was observed. Conclusion: CU1-LSLN is a novel preparation with great potential for treating liver cancer.

Solid lipid nanoparticle as an effective drug delivery system of a novel curcumin derivative: formulation, release in vitro and pharmacokinetics in vivo.

CONTEXT: Curcumin (Cur) has a short duration of action which limits its therapeutic efficacy. Carbonic acid 17-(1,5-dimethyl-hexyl)-10,13-dimethyl-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-3-yl ester 4-[7-(4-hydroxy-3-methoxy-phenyl)-3,5-dioxo-hepta-1,6-dienyl]-2-methoxy-phenyl ester (CUD), as a small molecule derivative of Cur with superior stability, has been developed in our laboratory. OBJECTIVE: CUD-loaded solid lipid nanoparticles (CUD-SLN) were prepared to prolong the duration of the drug action of Cur. MATERIALS AND METHODS: CUD-SLN were prepared with Poloxamer 188 (F68) and hydrogenated soybean phospholipids (HSPC) as carriers, and the prescription was optimized. The in vitro release of CUD and CUD-SLN was investigated. CUD-SLN (5 mg/kg) was injected into Sprague Dawley (SD) rats to investigate its pharmacokinetic behaviour. RESULTS: CUD-SLN features high entrapment efficiency (96.8 ± 0.4%), uniform particle size (113.0 ± 0.8 nm), polydispersity index (PDI) (0.177 ± 0.007) and an appropriate drug loading capacity (6.2 ± 0.1%). Optimized CUD-SLN exhibited sustained release of CUD for about 48 h. Moreover, the results of the pharmacokinetic studies showed that, compared to Cur, CUD-SLN had a considerably prolonged half-life of 14.7 h, slowed its metabolism in vivo by 35.6-fold, and had an improved area under the curve (AUC0-t) of 37.0-fold. CONCLUSIONS: CUD-SLN is a promising preparation for the development of a small molecule derivative of Cur.

Tetrandrine ameliorated Alzheimer's disease through suppressing microglial inflammatory activation and neurotoxicity in the 5XFAD mouse.

BACKGROUND: Alzheimer's disease (AD) is a neurodegenerative disorder prevalent in the aged population. Tetrandrine is a natural metabolite isolated from herbal medicine Stephania tetrandra with various activities. PURPOSE: In this study, we investigated the therapeutic role of tetrandrine in 5XFAD mouse, a transgenic model of AD. METHODS: 5XFAD mice were intraperitoneally injected with saline or different doses of tetrandrine (10, 20, and 40 mg/kg per 2 days) from the age of 5 months to 7 months followed by the determination of cognitive ability, amyloid plaque load, cell apoptosis, and inflammation in the brain. In vitro, the protective roles of tetrandrine against inflammatory activation of microglia and the resulting neurotoxicity were studied in BV2 cells and differentiated PC12 cells, respectively. RESULTS: Morris water maze test showed that two months of tetrandrine treatment dose-dependently improved the cognitive ability of 5XFAD mice. Immunostaining against Aß 1-42 demonstrated reduced amyloid plaque deposition in the brain of tetrandrine-treated 5XFAD mice. TUNEL assay revealed decreased cell apoptosis in the hippocampus after tetrandrine treatment. Further, RT-PCR showed that the ectopic transcription of inflammation-associated genes including TNFα, IL-1ß, IL-6, COX-2, iNOS, and p65 was reversed in 5XFAD mice treated with tetrandrine. In vitro, Aß 1-42 stimulated the secretion of inflammatory cytokines TNFα and IL-1ß in microglial BV2 cells as determined by ELISA, which was suppressed by tetrandrine pre-treatment. Tetrandrine pre-treatment also inhibited the expression of TLR4, p65, iNOS, and COX-2 in BV2 cells induced by Aß 1-42. Most importantly, treatment of PC12-derived neuron-like cells with conditional medium from Aß 1-42-stimulated BV2 cells remarkably impaired cell viability and promoted cell apoptosis, which was attenuated by the conditional medium from BV2 cells with tetrandrine pre-treatment. CONCLUSION: Collectively, findings in this study demonstrated that tetrandrine ameliorates AD by suppressing microglia-mediated inflammation and neurotoxicity.

In vitro and in vivo evaluation of curcumin loaded hollow microspheres prepared with ethyl cellulose and citric acid.

Curcumin (CUR) demonstrates a variety of biological activities; however, the poor oral bioavailability limits its clinical application. The objective of this study was to develop and evaluate characteristics and bioavailability of hollow microspheres loading curcumin (CUR-HPs). CUR-HPs were prepared by solvent diffusion and evaporation method. The effect of viscosity of ethyl cellulose (EC), amount of EC, citric acid (CA) and CUR on physicochemical characteristics and in vitro release profile of CUR-HPs were evaluated. Scanning electron microscopy (SEM) showed microspheres had smooth surfaces with hollow structures. The yield of CUR-HPs was (96 ±â€¯1.80) %. The floating rate at 24 h was (89.67 ±â€¯4.91) % and the drug loading was (3.41 ±â€¯0.21) %. Nearly 95% of CUR was released from the HPs at 24 h. In vitro release profiles of CUR-HPs fitted the Korsmeyer et al.'s equation and indicated that CUR was released through the combination of diffusion and erosion mechanisms. The bioavailability of CUR-HPs was 12-fold higher than that of CUR. The peak time was delayed for 7.5 h and peak concentration of CUR-HPs was 3.21 times than that of free CUR. The CUR-HPs might be a promising strategy to achieve sustained release and increase oral bioavailability of CUR.

Polymer blends used to develop felodipine-loaded hollow microspheres for improved oral bioavailability.

Felodipine (FD) has been widely used in anti-hypertensive treatment. However, it has extremely low aqueous solubility and poor bioavailability. To address these problems, FD hollow microspheres as multiple-unit dosage forms were synthesized by a solvent diffusion evaporation method. Particle size of the hollow microspheres, types of ethylcellulose (EC), amounts of EC, polyvinyl pyrrolidone (PVP) and FD were investigated based on an orthogonal experiment of three factors and three levels. In addition, the release kinetics in vitro and pharmacokinetics in beagle dogs of the optimized FD hollow microspheres was investigated and compared with Plendil (commercial FD sustained-release tablets) as a single-unit dosage form. Results showed that the optimal formulation was composed of EC10 cp:PVP:FD (0.9:0.16:0.36, w/w). The FD hollow microspheres were globular with a hollow structure and have high drug loading (17.69±0.44%) and floating rate (93.82±4.05%) in simulated human gastric fluid after 24h. Pharmacokinetic data showed that FD hollow microspheres exhibited sustained-release behavior and significantly improved relative bioavailability of FD compared with the control. Pharmacodynamic study showed that the FD hollow microspheres could effectively lower blood pressure. Therefore, these findings demonstrated that the hollow microspheres were an effective sustained-release delivery system for FD.