Psoralen-loaded lipid-polymer hybrid nanoparticles enhance doxorubicin efficacy in multidrug-resistant HepG2 cells

Background: Psoralen (PSO), a major active component of Psoralea corylifolia, has been shown to overcome multidrug resistance in cancer. A drug carrier comprising a lipid-monolayer shell and a biodegradable polymer core for sustained delivery and improved efficacy of drug have exhibited great potential in efficient treatment of cancers. Methods: The PSO-loaded lipid polymer hybrid nanoparticles were prepared and characterized. In vitro cytotoxicity assay, cellular uptake, cell cycle analysis, detection of ROS level and mitochondrial membrane potential (ΔΨm) and western blot were performed. Results: The P-LPNs enhanced the cytotoxicity of doxorubicin (DOX) 17-fold compared to free DOX in multidrug resistant HepG2/ADR cells. Moreover, P-LPNs displayed pro-apoptotic activity, increased levels of ROS and depolarization of ΔΨm. In addition, there were no significant effects on cellular uptake of DOX, cell cycle arrest, or the expression of P-glycoprotein. Mechanistic studies suggested that P-LPNs enhanced DOX cytotoxicity by increased release of cytochrome c and enhanced caspase3 cleavage, causing apoptosis in HepG2/ADR cells. Conclusion: The lipid-polymer hybrid nanoparticles can be considered a powerful and promising drug delivery system for effective cancer chemotherapy. Keywords: lipid-polymer hybrid nanoparticles, psoralen, drug delivery, HepG2, ADR cells, apoptosis.This work was supported by the National Natural Science Foundation of China (81273707), the Ministry of Education in the New Century Excellent Talents (NECT-12-0677), the Natural Science Foundation of Guangdong (S2013010012880, 2016A030311037), the Science and Technology Program of Guangzhou (2014J4500005, 201704030141), the Science Program of the Department of Education of Guangdong (2013KJCX0021, 2015KGJHZ012), the Science and Technology Program of Guangdong (2015A050502027), and the Special Project of International Scientific and Technological Cooperation in Guangzhou Development District (2017GH16)

Development of a Novel Primer–TaqMan Probe Set for Diagnosis and Quantification of Meloidogyne enterolobii in Soil Using qPCR and Droplet Digital PCR Assays

Early detection of pathogens before the planting season is valuable to forecast disease occurrence. Therefore, rapid and reliable diagnostic approaches are urgently needed, especially for one of the most aggressive root knot nematodes, Meloidogyne enterolobii. In this study, we developed a novel primer–TaqMan probe set aimed at M. enterolobii. The primer–probe set was successfully applied in the identification and quantification of M. enterolobii via qPCR technology. It was also suitable for improved PCR technology, known as ddPCR analyses, and this work presents the first application of this technology for plant parasitic nematodes. Compared with qPCR, ddPCR exhibited better performance with regard to analytical sensitivity, which can provide a more accurate detection of M. enterolobii concealed in field soil. In addition, we generated standard curves to calculate the number of eggs in soil using the qPCR and ddPCR platforms. Hopefully, the results herein will be helpful for forecasting disease severity of M. enterolobii infection and adopting effective management strategies

Occurrence and Identification of Root-Knot Nematodes on Red Dragon Fruit (Hylocereus polyrhizus) in Hainan, China

The genus Meloidogyne is one of the most economically damaging plant parasitic nematodes on a worldwide basis. To date, only the dragon fruits in Brazil were reported infected by M. javanica or M. incognita in previous surveys. From 2019–2021, we conducted our investigation in 62 orchards from 10 counties of Hainan, which are the main producing areas of dragon fruits in China. The collected roots were visually scored by gall index to evaluate the distribution and severity of diseases caused by Meloidogyne. Then, the isolated nematodes were further confirmed by a combination of morphological and molecular analysis. This survey revealed that the root-knot nematodes were widely distributed in red dragon fruit planting areas in Hainan and caused severe symptoms including stunting, wilting, and yellowing of the stems. The nematode populations were identified as M. enterolobii and M. javanica, among which, M. enterolobii accounted for a larger proportion, 93.9%. To our knowledge, this is the first report of M. enterolobii causing diseases on red dragon fruit. The results obtained from this survey will provide an insight into the presence of root-knot nematodes in dragon fruit plants. Also, these results will raise attention for developing effective management strategies to prevent further spread of root-knot nematodes on dragon fruit in Hainan

Molecular Characterization and Virus-Induced Gene Silencing of a Collagen Gene, Me-col-1, in Root-Knot Nematode Meloidogyne enterolobii

Meloidogyne enterolobii, a highly pathogenic root-knot nematode species, causes serious damage to agricultural production worldwide. Collagen is an important part of the nematode epidermis, which is crucial for nematode shape maintenance, motility, and reproduction. In this study, we report that a novel collagen gene, Me-col-1, from the highly pathogenic root-knot nematode species Meloidogyne enterolobi was required for the egg formation of this pathogen. Me-col-1 encodes a protein with the size of 35 kDa, which is closely related to collagen found in other nematodes. Real-time PCR assays showed that the expression of Me-col-1 was highest in eggs and lowest in pre-parasitic second-stage juveniles (preJ2). Interestingly, knockdown of Me-col-1 did not compromise the survival rate of preJ2 but significantly reduced the egg production and consequentially caused 35.79% lower multiplication rate (Pf/Pi) compared with control. Our study provides valuable information for better understanding the function of collagen genes in the nematode life cycle, which can be used in the development of effective approaches for nematode control

Occurrence and Identification of Root-Knot Nematodes on Red Dragon Fruit (<i>Hylocereus polyrhizus</i>) in Hainan, China

The genus Meloidogyne is one of the most economically damaging plant parasitic nematodes on a worldwide basis. To date, only the dragon fruits in Brazil were reported infected by M. javanica or M. incognita in previous surveys. From 2019–2021, we conducted our investigation in 62 orchards from 10 counties of Hainan, which are the main producing areas of dragon fruits in China. The collected roots were visually scored by gall index to evaluate the distribution and severity of diseases caused by Meloidogyne. Then, the isolated nematodes were further confirmed by a combination of morphological and molecular analysis. This survey revealed that the root-knot nematodes were widely distributed in red dragon fruit planting areas in Hainan and caused severe symptoms including stunting, wilting, and yellowing of the stems. The nematode populations were identified as M. enterolobii and M. javanica, among which, M. enterolobii accounted for a larger proportion, 93.9%. To our knowledge, this is the first report of M. enterolobii causing diseases on red dragon fruit. The results obtained from this survey will provide an insight into the presence of root-knot nematodes in dragon fruit plants. Also, these results will raise attention for developing effective management strategies to prevent further spread of root-knot nematodes on dragon fruit in Hainan

New Application of Quartz Crystal Microbalance: A Minimalist Strategy to Extract Adsorption Enthalpy

The capture and separation of CO2 is an important means to solve the problem of global warming. MOFs (metal–organic frameworks) are considered ideal candidates for capturing CO2, where the adsorption enthalpy is a crucial indicator for the screening of materials. For this purpose, we propose a new minimalist solution using QCM (quartz crystal microbalance) to extract the CO2 adsorption enthalpy on MOFs. Three kinds of MOFs with different properties, sizes and morphologies were employed to study the adsorption enthalpy of CO2 using a QCM platform and a commercial gas sorption analyzer. A Gaussian simulation calculation and previously data reported were used for comparison. It was found that the measuring errors were between 5.4% and 6.8%, proving the reliability and versatility of our new method. This low-cost, easy-to-use, and high-accuracy method will provide a rapid screening solution for CO2 adsorption materials, and it has potential in the evaluation of the adsorption of other gases

Fabrication of psoralen-loaded lipid-polymer hybrid nanoparticles and their reversal effect on drug resistance of cancer cells

In the present study, a lipid-polymer hybrid drug carrier system was developed to encapsulate psoralen (PSO), a multidrug resistance reversal agent and traditional Chinese medicine. Emphasis was focused the parameters that influence physicochemical characteristics, and then the drug release profile, stability, cytotoxicity and drug resistance reversal effect of the lipid-polymer hybrid nanoparticles (LPNs) were investigated. It was found that various formulation parameters affected NP size, drug loading (DL) and release characteristics. Hydrophilic 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-carboxy(polyethylene glycol)2000 increased the ζ potential and thus the stability of the NPs, but also enlarged their diameter. The amount of PSO influenced their DL and encapsulation efficiency, but did not show any effect on drug release kinetics. Next, the stability of the LPNs in different media and their storage characteristics were assessed. Finally, the cytotoxicity and multidrug resistance reversal effect was studied in the K562 and HepG2 cell lines. The analysis of half maximal inhibitory concentration values demonstrated that combination therapy with doxorubicin (DOX) and PSO-loaded LPNs (P-LPNs) was 14- and 23-fold more effective than a single-dose DOX treatment in resistant K562 and HepG2 cells, respectively, and 2.2- and 2.1-fold more effective than a single-dose combination regimen of DOX and PSO in solution, respectively. These data indicate that the LPNs have superior properties compared with a combination therapy in solution.This study was supported by the National Natural Science Foundation of China (grant no. 81273707), the Ministry of Education in the New Century Excellent Talents (grant no. NECT-12-0677), the Natural Science Foundation of Guangdong (grant nos. S2013010012880 and 2016A030311037), the Science and Technology Program of Guangzhou (grant nos. 2014J4500005 and 201704030141), the Science Program of the Department of Education of Guangdong (grant nos. 2013KJCX0021 and 2015KGJHZ012), the Science and Technology Program of Guangdong (grant no. 2015A050502027), and the Special Project of International Scientific and Technological Cooperation in Guangzhou Development District (grant no. 2017GH16)

Extraction of Polysaccharide from Spirulina and Evaluation of Its Activities

Background. Polysaccharide of Spirulina platensis (PSP) is a kind of water-soluble polysaccharide extracted from Spirulina platensis. It has been proved to have antitumor, antioxidation, antiaging, and antivirus properties. And it has a promising prospect for wide application. Objective. This study aims to identify an extraction process for high-purity polysaccharide in Spirulina (PSP) through a series of optimization methods and then evaluates its initial antiaging activities. Methods. Four kinds of extraction methods—hot-water extraction, alkali extraction, ultrasonic-assisted extraction, and freeze-thaw extraction—were compared to find the optimal one, which was further optimized by response surface methodology. PSP was obtained after the crude PSP was deproteinized and depigmented. The antiaging effects of PSP were preliminarily evaluated through in vitro cell experiments. Results. The alkali extraction method was determined as the optimal method, with the optimized extraction process consisting of a solid-liquid ratio of 1 : 50, a pH value of 10.25, a temperature of 89.24°C, and a time of 9.99 h. The final PSP contained 71.65% of polysaccharide and 8.54% of protein. At a concentration of 50 μg/mL, PSP exerted a significant promoting effect on the proliferation and traumatic fusion of human immortalized epidermal cells HaCaT. Conclusion. An extraction method for high-purity PSP with a high extraction rate was established, and in vitro results suggest antioxidation and antiaging activities