Jingfang granules protects against intracerebral hemorrhage by inhibiting neuroinflammation and protecting blood-brain barrier damage.

Intracerebral hemorrhage (ICH) can induce intensive oxidative stress, neuroinflammation, and brain cell apoptosis. However, conventional methods for ICH treatment have many disadvantages. There is an urgent need for alternative, effective therapies with minimal side effects. Pharmacodynamics experiment, molecular docking, network pharmacology, and metabolomics were adopted to investigate the treatment and its mechanism of Jingfang Granules (JFG) in ICH. In this study, we investigated the therapeutic effects of JFG on ICH using behavioral, brain water content and Magnetic resonance imaging experiments. However, the key active component and targets of JFG remain unknown. Here we verified that JFG was beneficial to improve brain injury after ICH. A network pharmacology analysis revealed that the anti-inflammatory effect of JFG is predominantly mediated by its activation of the phosphatidylinositol 3-kinase (PI3K)/AKT pathway through Luteolin, (+)-Anomalin and Phaseol and their targeting of AKT1, tumor necrosis factorα (TNF-α), and interleukin-1ß (IL-1ß). Molecular docking analyses revealed an average affinity of -8.633 kcal/mol, indicating a binding strength of less than -5 kcal/mol. Metabolomic analysis showed that JFG exerted its therapeutic effect on ICH by regulating metabolic pathways, such as the metabolism of taurine and hypotaurine, biosynthesis of valine, leucine, and isoleucine. In conclusion, we demonstrated that JFG attenuated neuroinflammation and BBB injury subsequent to ICH by activating the PI3K/Akt signaling pathway.

Mechanism of baixiangdan capsules on anti-neuroinflammation: combining dry and wet experiments.

Neuroinflammation plays an important role in the pathogenesis of neurological disorders, and despite intensive research, treatment of neuroinflammation remains limited. BaiXiangDan capsule (BXD) is widely used in clinical practice. However, systematic studies on the direct role and mechanisms of BXD in neuroinflammation are still lacking. We systematically evaluated the potential pharmacological mechanisms of BXD on neuroinflammation using network pharmacological analysis combined with experimental validation. Multiple databases are used to mine potential targets for bioactive ingredients, drug targets and neuroinflammation. GO and KEGG pathway analysis was also performed. Interactions between active ingredients and pivotal targets were confirmed by molecular docking. An experimental model of neuroinflammation was used to evaluate possible therapeutic mechanisms for BXD. Network pharmacological analysis revealed that Chrysoeriol, Kaempferol and Luteolin in BXD exerted their anti-neuroinflammatory effects mainly by acting on targets such as NCOA2, PIK3CA and PTGS2. Molecular docking results showed that their average affinity was less than -5 kcal/mol, with an average affinity of -8.286 kcal/mol. Pathways in cancer was found to be a potentially important pathway, with involvement of PI3K/AKT signaling pathways. In addition, in vivo experiments showed that BXD treatment ameliorated neural damage and reduced neuronal cell death. Western blotting, RT-qPCR and ELISA analysis showed that BXD inhibited not only the expression of IL-1ß, TNF-α and NO, but also NF-κB, MMP9 and PI3K/AKT signaling pathways. This study applied network pharmacology and in vivo experiments to explore the possible mechanisms of BXD against neuroinflammation, providing insight into the treatment of neuroinflammation.

The NLRP3 inflammasome is involved in resident intruder paradigm-induced aggressive behaviors in mice.

Background: Aggressive behaviors are one of the most important negative behaviors that seriously endangers human health. Also, the central para-inflammation of microglia triggered by stress can affect neurological function, plasticity, and behavior. NLRP3 integrates stress-related signals and is a key driver of this neural para-inflammation. However, it is unclear whether the NLRP3 inflammasome is implicated in the development of aggressive behaviors. Methods: First, aggressive behavior model mice were established using the resident intruder paradigm. Then, aggressive behaviors were determined with open-field tests (OFT), elevated plus-maze (EPM), and aggressive behavior tests (AT). Moreover, the expression of P2X7R and NLRP3 inflammasome complexes were assessed by immunofluorescence and Western blot. The levels of NLRP3 and inflammatory cytokines were evaluated using enzyme-linked immunosorbent assay (ELISA) kits. Finally, nerve plasticity damage was observed by immunofluorescence, transmission electron microscope, and BrdU staining. Results: Overall, the resident intruder paradigm induced aggressive behaviors, activated the hippocampal P2X7R and NLRP3 inflammasome, and promoted the release of proinflammatory cytokines IL-1ß in mice. Moreover, NLRP3 knockdown, administration of P2X7R antagonist (A804598), and IL-1ß blocker (IL-1Ra) prevented NLRP3 inflammasome-driven inflammatory responses and ameliorated resident intruder paradigm-induced aggressive behaviors. Also, the resident intruder paradigm promoted the activation of mouse microglia, damaging synapses in the hippocampus, and suppressing hippocampal regeneration in mice. Besides, NLRP3 knockdown, administration of A804598, and IL-1Ra inhibited the activation of microglia, improved synaptic damage, and restored hippocampal regeneration. Conclusion: The NLRP3 inflammasome-driven inflammatory response contributed to resident intruder paradigm-induced aggressive behavior, which might be related to neuroplasticity. Therefore, the NLRP3 inflammasome can be a potential target to treat aggressive behavior-related mental illnesses.

Research on the Mechanism of Asperosaponin VI for Treating Recurrent Spontaneous Abortion by Bioinformatics Analysis and Experimental Validation.

Asperosaponin VI (AS6), as the quality marker of Dipsaci Radix, is verified to exert therapeutic effect on alleviating recurrent spontaneous abortion (RSA). However, due to the lack of relevant research, its molecular mechanism is still unclear. We retrieved targets for AS6 and RSA, and then used their overlapped targets for PPI analysis. In addition, we used GO and KEGG enrichment analyses, and molecular docking to investigate the anti-RSA mechanisms of AS6. Furthermore, we conducted in vitro experiments to validate the predictions of network pharmacology. Results showed that a total of 103 AS6-associated targets and 2084 RSA-associated targets, with 49 targets overlapped. GO enrichment analysis showed 845 significant biological processes like decidualization, while KEGG pathway enrichment analysis revealed 76 significant entries including 18 signaling pathways, which were closely linked to PI3K-Akt, HIF-1, TNF, IL-17, and VEGF signaling pathways, etc. Molecular docking findings verified that AS6 had tight link with the key targets including JUN, CASP3, STAT3, SRC, and PTGS2. Notably, in vitro experiments revealed that AS6 treatment could exert lower expressions of JUN, pro-CASP3, CASP3, STAT3, SRC, and PTGS2 in decidual cells compared with progesterone despite the expressions of STAT3, SRC, and PTGS2 with no significant difference, and mifepristone could interfere with the effects. In general, numerous targets and multiple pathways involve during the process of AS6 treatment against RSA. Moreover, our in vitro research first reported that AS6 may regulate the expressions of key targets (JUN, CASP3, STAT3, SRC, and PTGS2) in decidual cells to promote decidualization, thus treating RSA.

Mechanical forces on trophoblast motility and its potential role in spiral artery remodeling during pregnancy.

During the first trimester of pregnancy, cytotrophoblasts (CTBs) differentiate into extravillous trophoblasts (EVTs). EVTs migrate from villus to decidua, invade maternal spiral arteries (SAs) and more strikingly, they migrate against blood flow along the vessels and replace endothelial cells (ECs), completing SA remodeling. Studies have indicated that trophoblast cells are mechanosensitive. They assemble ECs, which can align in the direction of fluid flow. However, how they sense blood flow and transform mechanical stimulations into chemical signals remain largely unexplored. What factors trigger their motility? what are the potential and major factors that guide them to find their path and empower them to migrate against flow? To answer these intricate questions, this review provides some of the novel aspects and sheds new insights into clinical applications.

Identification of Key Molecules in Recurrent Miscarriage Based on Bioinformatics Analysis.

BACKGROUND: Recurrent Miscarriage (RM) affects 1% to 5% of couples, and the mechanisms still stay unclear. In this study, we explored the underlying molecular mechanism and potential molecular biomarkers of RM as well as constructed a miRNA-mRNA regulation network. METHODS: The microarray datasets GSE73025 and GSE22490, which represent mRNA and miRNA profiles, respectively, were downloaded from the Gene Expression Omnibus (GEO) database. Differentially Expressed Genes (DEGs) with p-value < 0.05 and fold-change > 2 were identified while the miRNAs with p-value < 0.05 and fold-change > 1.3 were considered as significant differentially expressed miRNAs (DEMs). RESULTS: A total of 373 DEGs, including 218 up-regulated genes and 155 down-regulated genes, were identified, while 138 up-regulated and 68 down-regulated DEMs were screened out. After functional enrichment analysis, we found GO Biological Process (BP) terms significantly enriched in the Fc-gamma receptor signaling pathway involved in phagocytosis. Moreover, signaling pathway analyses indicated that the neurotrophin signaling pathway (hsa04722) was the top KEGG enrichment. 6 hub genes (FPR1, C5AR1, CCR1, ADCY7, CXCR2, NPY) were screened out to construct a complex regulation network in RM because they had the highest degree of affecting the network. Besides, we constructed miRNA-mRNA network between DEMs target genes and DEGs in RM, including hsa-miR-1297- KLHL24 and hsa-miR-548a-5p-KLHL24 pairs. CONCLUSION: In conclusion, the novel differentially expressed molecules in the present study could provide a new sight to explore the pathogenesis of RM as well as potential biomarkers and therapeutic targets for RM diagnosis and treatment.

Targeting NLRP3 Inflammasome in Translational Treatment of Nervous System Diseases: An Update.

Neuroinflammatory response is the immune response mechanism of the innate immune system of the central nervous system. Both primary and secondary injury can activate neuroinflammatory response. Among them, the nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome plays a key role in the inflammatory response of the central system. Inflammasome is a type of pattern recognition receptor, a cytoplasmic polyprotein complex composed of members of the Nod-like receptor (NLR) family and members of the pyrin and HIN domain (PYHIN) family, which can be affected by a variety of pathogen-related molecular patterns or damage-related molecular patterns are activated. As one of the research hotspots in the field of medical research in recent years, there are increasing researches on immune function abnormalities in the onset of neurological diseases such as depression, AD, ischemic brain injury and cerebral infarction, the NLRP3 inflammasome causes the activated caspase-1 to cleave pre-interleukin-1ß and pre-interleukin-18 into mature interleukin-1ß and interleukin-18, in turn, a large number of inflammatory factors are produced, which participate in the occurrence and development of the above-mentioned diseases. Targeted inhibition of the activation of inflammasomes can reduce the inflammatory response, promote the survival of nerve cells, and achieve neuroprotective effects. This article reviews NLRP3 inflammasome's role in neurological diseases and related regulatory mechanisms, which providing references for future research in this field.

RNA Demethylase FTO Mediated RNA m6A Modification Is Involved in Maintaining Maternal-Fetal Interface in Spontaneous Abortion.

The N6-methyladenosine (m6A) RNA modification regulates the expression of genes associated with various biological and pathological processes, including spontaneous abortion (SA). The aim of this study was to determine the role of the m6A demethylase fat mass and obesity (FTO)- associated protein in SA. The FTO,IGF2BP1 and IGF2BP2 mRNA levels were significantly lower in the chorionic villi obtained from spontaneously aborted pregnancies compared to that of normal pregnancies, while the expression levels of METTL3 and WTAP were significantly elevated. However, ALKBH5, YTHDF2, and IGF2BP3 were elevated with no statistical significance between groups. In addition, MDA was elevated and SOD levels were decreased in the villi tissues of the SA group compared to the normal group, which was indicative of placental oxidative stress in the former. Furthermore, the expression of FTO and HLA-G were significantly decreased in the trophoblasts of the SA patients compared to that of normal pregnant women, while that of m6A was markedly higher in the former. In addition, the HLA-G and VEGFR mRNA levels were downregulated in the SA versus the control group, and that of MMP2, MMP7, MMP9 and VEGFA were upregulated. Finally, The RIP assay showed significantly decreased levels of FTO-bound HLA-G, VEGFR and MMP9 RNA in SA patients (P < 0.05), which corresponded to an increase in transcripts enriched with the m6A antibody (P < 0.05). However, compared with normal pregnant women, the levels of HLA-G, VEGFA, VEGFR, and MMP2 mRNA bound by YTHDF2 were significantly decreased in SA patients. Compared to the normal pregnant women, both FTO- and m6A-bound MMP7 were significantly increased in SA patients (P < 0.05), but YTHDF2 almost unbound to MMP7 mRNA. In summary, the downregulation of FTO in the chorionic villi disrupts immune tolerance and angiogenesis at the maternal-fetal interface, resulting in aberrant methylation and oxidative stress that eventually leads to SA.

Circulating microRNAs from serum exosomes as potential biomarkers in patients with spontaneous abortion.

BACKGROUND: Spontaneous abortion (SA) is a common complication in early pregnancy. Nevertheless, SA's etiology is complex, and the underlying molecular mechanisms of the pathogenesis behind SA remains unclear. The present study aims to find the feasibility of using serum exosomal miRNAs as novel biomarkers for SA. METHODS: In our study, we isolated the serum exosomes from the peripheral blood of the subjects. Then transmission electron microscopy (TEM), WB, and in vitro exosome tracing experiments were used. Comprehensive exosomal miRNA sequencing was performed to profile the differentially expressed miRNAs between the SA and normal pregnancy groups. Furthermore, genes targeted by miRNAs were further predicted and verified by TargetScan, miRDB, miRTarBase, miRWalk and HMDD V3.2. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and pathway category were performed by the DIANA-miRPath v3.0 online tool. We then validated the expression levels of selected miRNAs by qRT-PCR. ROC analysis was performed to explore the clinical utility of the two miRNA as biomarkers for SA. RESULTS: TEM, NTA measurements and WB analysis showed the successful isolation of exosomes. Exosome labeling by PKH26 proved that exosomes could be efficiently taken up by primary decidual cells. Sequencing data found that with a total of 2,588, there were 189 significantly expressed exosomal miRNAs between the two groups. The most significantly expressed miRNA (miR-371a-5p, miR-206, miR-147b, miR-6859-5p, miR-410-3p, miR-1270 and miR-524-5p) were selected for further analysis. Through KEGG pathway analysis and pathway category, nine risk pathways were revealed. Among them, the Wnt signaling pathway, the Hippo signaling pathway, and the FoxO signaling pathway were pinpointed as major high-risk pathways. As a single marker, miR-371a-5p and miR-206 had a specificity of 83.3% and 70.8% at the sensitivity of 62.5% and 66.7%, respectively. The combined two markers achieved a specificity of 75% at the sensitivity of 79.2%. CONCLUSIONS: Our results suggest that the circulating miRNAs from exosomes are altered in patients with SA. Findings of this exploratory study may provide potential biomarkers for SA.

Association between Dietary Vitamin A and HPV Infection in American Women: Data from NHANES 2003-2016.

OBJECTIVE: Evidence regarding the relationship between vitamin A and HPV infection was limited. Therefore, this study is designed to investigate whether vitamin A was independently related to HPV infection in 13412 American women from NHANES for seven cycles. METHODS: The present study is a cross-sectional study. A total of 13412 eligible participants who had available HPV tests and vitamin A intake data were registered in the NHANE database from 2003 to 2016. The targeted independent variable and the dependent variable were vitamin A measured at baseline and HPV infection, respectively. We analyzed the association between dietary vitamin A intake and the prevalence of HPV infection. Besides, GAM and smooth curve fittings were used to address the nonlinear relationship between vitamin A and HPV infection to determine the effect of HPV infection. RESULTS: The result of fully adjusted binary logistic regression showed vitamin A was not associated with the risk of HPV infection after adjusting confounders (odds ratio = 0.97, 95% confidence interval: 0.97-1.02). A nonlinear relationship was detected between vitamin A and HPV infection, whose inflection point was 10.5 of log2 vitamin A (by the recursive algorithm). One unit increase of log2 vitamin A is associated with the 10% reduced risk of HPV infection when dietary vitamin A is < 1448.155mcg. Conversely, when the dietary vitamin A intake is ≧1448.155 mcg, for each additional log2 of vitamin A, the risk of HPV infection increased by 70%. CONCLUSIONS: We found that dietary vitamin A was quite different from the trend of HPV infection in different confidence intervals. The results suggested that an appropriate amount (95% CI: 0.9-1.0, <10.5 of log2 transformer, i.e., 1448.155 mcg) of dietary vitamin A may be beneficial to prevent HPV infection. However, excessive intake of dietary vitamin A (95% CI: 1.1-2.8, ≧10.5 of log2 transformer, i.e., 1448.155 mcg) may increase the risk of HPV infection.

The benefits of higher LMR for early threatened abortion: A retrospective cohort study.

PROBLEM: To investigate the relation of inflammation-related parameters and pregnancy outcome in women with the early threatened abortion. METHOD OF STUDY: 630 women with early threatened abortion were divided into two groups based on the pregnancy outcome. All of them had the blood routine examination before treating. The differences between two groups were analyzed by the Chi-squared test, Student T test, Mann-Whitney U test, Binary Logistic Regression, Marginal Structural Model and Threshold effect analysis. RESULTS: We found that there is no significant difference in the pregnancy outcome for NLR (OR:0.92, CI95%:0.72, 1.17) and PLR (OR:1.00, CI%:0.99, 1.01). However, a difference had a statistical significance in the pregnancy outcome when LMR less than 2.19 (OR:0.39, CI95%:0.19,0.82). CONCLUSIONS: This study suggested that higher LMR was related to the lower risk of miscarriage in the women with early threatened abortion in a way.

Zn(ii) coordination to cyclen-based polycations for enhanced gene delivery.

1,4,7,10-Tetraazacyclododecane (cyclen) has a unique cyclic structure that endows it with a number of characteristics, including its cationic nature, easy modification and strong coordination ability toward a wide range of cations. Zn2+, which can easily coordinate to cyclen, is an essential metal ion for DNA binding. In this report, Zn(ii)-polycations derived from cyclen were studied as non-viral gene delivery vectors. Polycations were synthesized from diglycidyl ethers and cyclen through ring-opening polymerization, and then Zn(ii)-complexes were obtained by reacting the polycations with Zn(NO3)2·6H2O. UV absorption and circular dichroism spectra revealed that the Zn(ii)-complexes may induce apparent conformational changes of DNA, while polycations could not. Agarose gel retardation assay demonstrated that although the Zn(ii)-polycations exhibited slightly lower DNA binding ability compared to their polycation counterparts, they showed better DNA release, which might favor the gene transfection process. In vitro transfection results revealed that the coordination of Zn(ii) may dramatically increase the transfection efficiency of the polymers. In addition, almost all polycations and their Zn(ii)-complexes exhibited better serum tolerance than polyethylenimine (PEI), especially Zn-cyclen-HD. Flow cytometry and BSA adsorption experiments also demonstrated the good serum tolerance of the Zn(ii)-polycations. Meanwhile, such materials also exhibited acceptable cytotoxicities at transfection dosages. These results may afford us clues for developing novel non-viral gene vectors with high efficiency and biocompatibility.

Low molecular weight PEI-based fluorinated polymers for efficient gene delivery.

Fluorinated biomaterials have been reported to have promising features as non-viral gene carriers. In this study, a series of fluorinated polymeric gene carriers were synthesized via Michael addition from low molecular weight polyethyleneimine (PEI) and fluorobenzoic acids (FBAs)-based linking compounds with different numbers of fluorine atoms. The structure-activity relationship (SAR) of these materials was systematically investigated. SAR studies showed that fluorine could screen the positive charge of these polymers. However, this shielding effect of fluorine would endow fluorinated polymers with good balance between DNA condensation and release. In vitro transfection results suggested that these fluorinated polymers could mediate efficient gene delivery. Flow cytometry and confocal microscopy studies demonstrated that more efficient cell uptake could be achieved by fluorinated materials with more fluorine atoms. Cytotoxicity assays showed that these fluorinated materials exhibited very low cytotoxicity even at high mass ratios. This study demonstrates that FBA-based fluorinated biopolymers have the potential for practical application.

Effect of Total Flavones from Cuscuta Chinensis on Anti-Abortion via the MAPK Signaling Pathway.

For centuries, the Chinese herb Cuscuta chinensis has been applied clinically for abortion prevention in traditional Chinese medicine (TCM). Total flavones extracted from Cuscuta chinensis (TFCC) are one of the active components in the herb and also display anti-abortion effect similar to the unprocessed material. However, how TFCC exerts the anti-abortion effect remains largely unknown. In this study, we aim at characterizing the anti-abortion effects of TFCC and its underlying molecular mechanism in vitro and in vivo using human primary decidua cells and a mifepristone-induced abortion model in rat, respectively. The damage to the decidua caused by mifepristone in vivo was reversed by TFCC treatment in a dosage-dependent manner. High dosage of TFCC significantly upregulated the expression of estrogen receptor (ER), progesterone receptor (PR), and prolactin receptor (PRLR) in decidua tissue but downregulated the expression of p-ERK. Furthermore, we detected higher level of p-ERK and p-p38 in primary decidua cells from spontaneous abortion while treatment by TFCC downregulated their expression. Our results suggest TFCC mediates its anti-abortion effect by interfering with MAPK signaling pathway.

Pulsatilla decoction inhibits Candida albicans proliferation and adhesion in a mouse model of vulvovaginal candidiasis via the Dectin-1 signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Pulsatilla decoction (PD) is a classical prescription in Traditional Chinese Medicine (TCM) and has been reported to have inhibitory effects on Candida albicans proliferation. STUDY AIM: To investigate the therapeutic effects of PD in the treatment of Vulvovaginal candidiasis (VVC) and elucidate the potential mechanism. MATERIALS AND METHODS: Female BALB/c mice (N = 90) were randomized to six treatment groups, including the Control group, Model group, three PD groups and Fluconazole group which served as a positive control (20 mg/kg weekly). The three PD groups (low dose group, medium dose group and high dose group) were given a daily intragastric gavage of PD at doses of 5, 10 and 20 g/kg, respectively. Five animals from each group were euthanized on Day 4, Day 7 and Day 14 after treatment. Colony forming unit (CFU) was measured by the serial dilution method. The degree of infection was assessed by Gram staining, Periodic acid schiff (PAS) staining, Hematoxylin and eosin (H&E) staining and Scanning electron microscopy (SEM). The serum inflammation levels were determined by a Luminex assay. Gene and protein expression levels of components of the Dectin-1 signaling pathway were determined by Real-time PCR, Western-blot and immunohistochemistry, respectively. RESULTS: The administration of PD significantly decreased the fungal load from Day 7 post-infection onwards and decreased the number of visible microorganisms based on findings from Gram staining, PAS staining and SEM. H&E staining indicated that the impaired histological profiles were improved in all three PD groups. PD led to a significantly lower level of IL-23 in the serum; the levels of IL-10 and TNF-α were also decreased, although the differences were not significant. Furthermore, a substantial downregulation of Dectin-1, CARD9 and NF-κB mRNA levels and Dectin-1, Syk, CARD9 and NF-κB protein levels was observed after the administration of PD. CONCLUSION: This study suggests that PD exerts inhibitory effects on C. albicans proliferation, adhesion and inflammation and simultaneously downregulates the expression levels of important genes and proteins associated with the Dectin-1 pathway, highlighting the potential application of PD to improve the clinical management of VVC.

Rigid aromatic linking moiety in cationic lipids for enhanced gene transfection efficiency.

Although numerous cationic lipids have been developed as non-viral gene vectors, the structure-activity relationship (SAR) of these materials remains unclear and needs further investigation. In this work, a series of lysine-derived cationic lipids containing linkages with different rigidity were designed and synthesized. SAR studies showed that lipids with rigid aromatic linkage could promote the formation of tight liposomes and enhance DNA condensation, which is essential for the gene delivery process. These lipids could give much higher transfection efficiency than those containing more flexible aliphatic linkage in various cell lines. Moreover, the rigid aromatic linkage also affords the material higher serum tolerance ability. Flow cytometry assay revealed that the target lipids have good cellular uptake, while confocal microscopy observation showed weaker endosome escape than Lipofectamine 2000. To solve such problem and further increase the transfection efficiency, some lysosomotropic reagents were used to improve the endosome escape of lipoplex. As expected, higher transfection efficiency than Lipofectamine 2000 could be obtained via this strategy. Cytotoxicity assay showed that these lipids have lower toxicity in various cell lines than Lipofectamine 2000, suggesting their potential for further application. This work demonstrates that a rigid aromatic linkage might distinctly improve the gene transfection abilities of cationic lipids and affords information to construct safe and efficient gene vector towards practical application.

Aromatic Modification of Low Molecular Weight PEI for Enhanced Gene Delivery.

Low molecular weight polyethylenimine (1800 Da, also referred to as oligoethylenimines, OEI) was modified with amino acids, including two aromatic amino acids (tryptophan, phenylalanine) and an aliphatic amino acid (leucine). The substitution degree of amino acids could be controlled by adjusting the feeding mole ratio of the reactants. Fluorescence spectroscopy and circular dichroism experiments demonstrated that the indole ring of tryptophan may intercalate into the DNA base pairs and contribute to efficient DNA condensation. In vitro gene expression results revealed that the modified OEIs (OEI-AAs) may provide higher transfection efficiency even than high molecular weight polyethylenimine (25 kDa, PEI), especially the aromatic tryptophan substituted OEI. Moreover, OEI-AAs exhibited excellent serum tolerance, and up to 137 times higher transfection efficiency than PEI 25 kDa that was obtained in the presence of serum. The cytotoxicity of OEI-AAs is much lower than PEI 25 kDa. This study may afford a new method for the development of low molecular weight oligomeric non-viral gene vectors with both high efficiency and biocompatibility.

Bio-reducible polycations from ring-opening polymerization as potential gene delivery vehicles.

Synthetic polycations show great potential for the construction of ideal non-viral gene delivery systems. Several cationic polymers were synthesized by the epoxide ring-opening polymerization between diepoxide and various polyamines. Disulfide bonds were introduced to afford the polymers bio-reducibility, while the oxygen-rich structure might enhance the serum tolerance and biocompatibility. The polycations have much lower molecular weights than PEI 25 kDa, but still could well bind and condense DNA into nano-sized particles. DNA could be released from the polyplexes by addition of reductive DTT. Compared to PEI, the polycations have less cytotoxicity possibly due to their lower molecular weights and oxygen-rich structure. More significantly, these materials exhibit excellent serum tolerance than PEI, and up to 6 times higher transfection efficiency than PEI could be obtained in the presence of serum. The transfection mediated by was seldom affected even at a high concentration of serum. Much lower protein adsorption of polycations than PEI was proved by bovine serum albumin adsorption experiments. Flow cytometry also demonstrates their good serum resistance ability.

Low Molecular Weight Oligomers with Aromatic Backbone as Efficient Nonviral Gene Vectors.

A series of oligomers were synthesized via ring-opening polymerization. Although the molecular weights of these oligomers are only ∼2.5 kDa, they could efficiently bind and condense DNA into nanoparticles. These oligomers gave comparable transfection efficiency (TE) to PEI 25 kDa, while their TE could even increase with the presence of serum, and up to 65 times higher TE than PEI was obtained. The excellent serum tolerance was also confirmed by TEM, flow cytometry, and BSA adsorption assay. Moreover, structure-activity relationship studies revealed some interesting factors. First, oligomers containing aromatic rings in the backbone showed better DNA binding ability. These materials could bring more DNA cargo into the cells, leading to much better TE. Second, the isomerism of the disubstituted phenyl group on the oligomer backbone has large effect on the transfection. The ortho-disubstituted ones gave at least 1 order of magnitude higher TE than meta- or para-disubstituted oligomers. Gel electrophoresis involving DNase and heparin indicated that the difficulty to release DNA might contribute to the lower TE of the latter. Such clues may help us to design novel nonviral gene vectors with high efficiency and biocompatibility.

Ring-opening polymerization for hyperbranched polycationic gene delivery vectors with excellent serum tolerance.

In order to improve the transfection efficiency (TE) and biocompatibility, we synthesized a series of hyperbranched cationic polymers by ring-opening polymerization between diepoxide and several polyamines. These materials can condense plasmid DNA efficiently into nanoparticles that have much lower cytotoxicity than those derived from bPEI. In vitro transfection experiments showed that polymers prepared from branched or cyclic polyamine (P1 and P5) exhibited TE several times higher than 25KDa bPEI. More significantly, serum seemed to have no negative effect on P1-P5 mediated transfection. On the contrary, the TE of P1 improved, even when the serum concentration reached 70%. Several assays demonstrated the excellent serum tolerance of such polycationic vectors: bovine serum albumin (BSA) adsorption assay revealed considerably lower protein adsorption of P1-P5 than PEI; P1 showed better DNA protection ability from degradation by DNase I than PEI; flow cytometry results suggested that any concentration of serum may not decrease the cellular uptake of P1/DNA polyplex; and confocal laser scanning microscopy also found that serum has little effect on the transfection. By using specific cellular uptake inhibitors, we found that the polyplexes enter the cells mainly via caveolae and microtubule-mediated pathways. We believe that this ring-opening polymerization may be an effective synthetic approach toward gene delivery materials with high biological activity.