Dexamethasone-Loaded Lipid Calcium Phosphate Nanoparticles Treat Experimental Colitis by Regulating Macrophage Polarization in Inflammatory Sites.

Background: The M1/M2 polarization of intestinal macrophages exerts an essential function in the pathogenesis of ulcerative colitis (UC), which can be adjusted to alleviate the UC symptoms. Purpose: A kind of pH-sensitive lipid calcium phosphate core-shell nanoparticles (NPs), co-loading with dexamethasone (Dex) and its water-soluble salts, dexamethasone sodium phosphate (Dsp), was constructed to comprehensively regulate macrophages in different states towards the M2 phenotype to promote anti-inflammatory effects. Methods: Dex and Dsp were loaded in the outer lipid shell and inner lipid calcium phosphate (Cap) core of the LdCaPd NPs, respectively. Then, the morphology of NPs and methods for determining drug concentration were investigated, followed by in vitro protein adsorption, stability, and release tests. Cell experiments evaluated the cytotoxicity, cellular uptake, and macrophage polarization induction ability of NPs. The in vivo distribution and anti-inflammatory effect of NPs were evaluated through a 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced BALB/c mice ulcerative colitis model. Results: The LdCaPd NPs showed a particle size of about 200 nm and achieved considerable loading amounts of Dex and Dsp. The in vitro and in vivo studies revealed that in the acidic UC microenvironment, the cationic lipid shell of LdCaPd underwent protonated dissociation to release Dex first for creating a microenvironment conducive to M2 polarization. Then, the exposed CaP core was further engulfed by M1 macrophages to release Dsp to restrict the pro-inflammatory cytokines production by inhibiting the activation and function of the nuclear factor kappa-B (NF-κB) through activating the GC receptor and the NF kappa B inhibitor α (I-κBα), respectively, ultimately reversing the M1 polarization to promote the anti-inflammatory therapy. Conclusion: The LdCaPd NPs accomplished the sequential release of Dex and Dsp to the UC site and the inflammatory M1 macrophages at this site, promoting the regulation of macrophage polarization to accelerate the remission of UC symptoms.

M3 muscarinic acetylcholine receptor is associated with beta-catenin in ventricular myocytes during myocardial infarction in the rat.

1. The present study was designed to investigate whether the M(3) muscarinic acetylcholine receptors (mAChR) is associated with beta-catenin in the ventricular myocardium during ischaemic myocardial injury and to determine the possible mechanism/s involved. 2. Rat hearts were subjected to coronary artery ligation for 1 and 6 h or 1 month to establish a myocardial ischaemia (MI) model. In the acute MI model, 16 rats were randomized into four groups: (i) control; (ii) ischaemia (rats were subjected to 20 min coronary occlusion); (iii) choline (10 mg/kg, i.v., choline chloride, an M(3) receptor agonist, was administered 15 min before occlusion); and (iv) 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP; 0.12 mg/kg 4-DAMP, an M(3) receptor antagonist, was administered 20 min before occlusion, followed 5 min later by 10 mg/kg, i.v., choline chloride). Immunochemistry, western blot analysis and immunoprecipitation were used to determine the expression and localization of beta-catenin and the M(3) mAChR. 3. Myocardial ischaemia caused a time-dependent increase in the expression of beta-catenin. Moreover, a physical association was found between beta-catenin and the M(3) mAChR in intercalated discs. This association was enhanced by prolonged ischaemia. Administration of choline before ischaemia not only increased beta-catenin expression, but also strengthened the association between beta-catenin and the M(3) mAChR. However, blockade of M(3) mAChR by 4-DAMP completely inhibited the effect of choline on the expression of beta-catenin. In addition, MI increased phosphorylation of the M(3) mAChR. 4. The results indicate that increased beta-catenin activity is associated with M(3) mAChR during MI. This association is likely to play a role in heart signal transduction during ischaemia between neighbouring ventricular myocardiocum.

Anti-neoplastic efficacy of Haimiding on gastric carcinoma and its mechanisms.

AIM: To study the anti-neoplastic effect of Haimiding and its mechanisms of action. METHODS: Experiments using MTT and colony formation were carried out to study the in vitro anti-neoplastic action of Haimiding, its in vivo anti-neoplastic action was studied by observing its effect on the weight of tumors in FC mice and S(180), H(22) tumor bearing mice, as well as their life spans. The effect of Haimiding on cell apoptosis and different stages of cell cycles in human gastric carcinoma cells were studied by flow cytometry. Its effect on [Ca(2+)](i) of human gastric carcinoma cells and the source of Ca(2+) during the change of [Ca(2+)](i) were observed by confocal laser scanning technique. RESULTS: Haimiding showed a definite cytotoxicity to 8 human tumor cell lines, which was most prominent against BGC-823, E(ca-109) and HCT-8 tumor cells. It also exhibited an obvious inhibition on colony formation of the above tumor cell lines, which was most prominent in E(ca-109) tumor cells. It showed obvious inhibition on the growth of tumor in FC mice and S(180) bearing mice as well as prolonged the life span of H(22) bearing mice. It was able to induce apoptosis and elevate intracellular [Ca(2+)](i) concentration of tumor cells. The source of Ca(2+) came from both extracellular Ca(2+) influx and intracellular Ca(2+) release. CONCLUSION: Haimiding is composed of a TCM preparation and 5-flurouracil. Its anti-neoplastic potency is highly enhanced by synergism as compared with either one of its components. Its mechanisms of anti-neoplastic action can be attributed to its action to initiate apoptosis of tumor cells by opening the membrane calcium channel and inducing intracellular Ca(2+) release to elevate [Ca(2+)](i) of the tumor cells.