Production of nitric oxide and tumor necrosis factor-alpha by Smilacis rhizoma in mouse peritoneal macrophages

Using mouse peritoneal macrophages, we have examined the mechanism by which, Smilacis rhizoma (SR) regulates nitric oxide (NO) production. When SR was used in combination with recombinant interferon-gamma (rIFN-gamma), there was a marked cooperative induction of NO production. However, SR had no effect on NO production by itself. The increased production of NO from rIFN-gamma plus SR-stimulated cells was almost completely inhibited by pre-treatment with pyrrolidine dithiocarbamate (PDTC), an inhibitor of nuclear factor kappa B (NF-kappaB). Furthermore, treatment of peritoneal macrophages with rIFN-gamma plus SR caused a significant increase in tumor necrosis factor-alpha (TNF-alpha) production. PDTC also decreased the effect of SR on TNF-alpha production significantly. These findings demonstrate that SR increases the production of NO and TNF-alpha by rIFN-gamma-primed macrophages and suggest that NF-kappaB plays a critical role in mediating these effects of SR.     

Polysaccharide isolated from seeds of Plantago asiatica L. induces maturation of dendritic cells through MAPK and NF-κB pathway

Plantago species are used as traditional medicine in Asian and Europe. Polysaccharide isolated from the seeds of Plantago asiatica L. could stimulate maturation transformation of bone-marrow derived dendritic cells (DCs). We found that blocking p38, ERK1/2 and JNK MAPK signal transduction could significantly decreased the PLP-2 induced expression of MHC II, CD86 surface molecules on DCs. Blocking p38 and JNK signal also significantly inhibited the cytokine secretion of TNF-α and IL-12p70 as well, while blocking ERK1/2 signal only decreased the secretion of TNF-α. Meanwhile, DCs in the three MAPK signal-blocking groups showed dramatically attenuated effects on stimulating proliferation of T lymphocytes. Similarly, blocking signal transduction of NF-κB pathway also significantly impaired the phenotypic and functional maturation development of DCs induced by PLP-2. These data suggest that MAPK and NF-κB pathway mediates the PLP-induced maturation on DCs. Especially, among the three MAPK pathways, activation of JNK signal transduction is the most important for DCs development after PLP-2 incubation. And PLP-2 may activate the MAPK and NF-κB pathway by triggering toll-like receptor 4 on DCs.     

Estimation of nitric oxide level in vivo by microdialysis with water-soluble iron-N-methyl-d-dithiocarbamate complexes as NO traps: A novel approach to nitric oxide spin trapping in animal tissues

It was found that microdialysis, i.e., passage of aqueous solutions of iron-N-methyl-d-glucamine dithiocarbamate complexes through dialysis fibers implanted into heart, kidney and liver tissues of narcotized rats, was accompanied by effective binding of the complexes to nitric oxide from interstitial fluid. The walls of dialysis fibers used in this study were permeable for compounds with molecular weight not exceeding 5 kDa. The dialyzate samples collected every 20 min and containing diamagnetic nitrosyl Fe³⁺-MGD adducts were reduced to the paramagnetic state with sodium dithionite; their concentration was measured by the EPR method. The basic level of the adducts, which represented mononitrosyl iron complexes with MGD (MNIC–MGD), in the dialyzate samples of all tested organs were similar (1 μМ). Treatment of animals with the water-soluble nitroglycerine analog Isoket or a low-molecular dinitrosyl iron thiosulfate complex as a NO donor increased the concentration of MNIC–MGD with going out into a plateau. The novel approach allows determination of nitric oxide levels in tissue interstitial fluid from concentration of MNIC–MGD formed during microdialysis.     

Evidence for metal to solvent charge transfer photooxidation of iron, cobalt, nickel and copper dithiocarbamato derivatives in poly(vinylchloride) matrices at ca. 90 K: New insights into the bonding of late transition metals with dithiocarbamate ligands through DFT modeling

Photolysis of FeL₃, CoL₃, NiL₂, CuL₂ and ZnL₂, where L = S₂CNEt₂, in PVC matrices at ca. 90 K results in photooxidation of the metal complexes through irreversible metal to solvent charge transfer. DFT quantum mechanical studies of the S₂CNMe₂ anion and the Ni, Cu and Zn derivatives were carried out, providing a more nuanced understanding of the bonding of the dithiocarbamate ligand than suggested by classical resonance arguments.     

Thalidomide dithiocarbamate and dithioate derivatives induce apoptosis through inhibition of histone deacetylases and induction of caspases

Anti-cancer effect and mechanism of cell death were investigated in a battery of five thalidomide analogs containing one sulfur atom 2 or two sulfur atoms 3–6 and were compared with thalidomide 1 activity. The cytotoxic effect of thalidomide analogs 2–6 against Hep-G2, 1301, and HCT-116 cells was estimated by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Apoptosis and necrosis cell percentage was stained by ethidium bromide and acridine orange, DNA fragmentation, inhibition of histone deacetylase (HDAC), and total caspases were assayed by universal procedures and kits. We report here for the anti-cancer activity of thalidomide dithiocarbamate analog 3 and thalidomide dithioate analog 5 against Hep-G2 and HCT-116 cells, which was more cytotoxic than thalidomide itself, and that the cytotoxicity was associated with DNA fragmentation and was due to apoptosis and not necrosis. Moreover, we suggest that the cell death pathway is evoked by thalidomide dithiocarbamate analog 3 and thalidomide dithioate analog 5 in human hepatocellular carcinoma cells through multiple consequences that trigger apoptotic cell death; involving the enhancement of DNA fragmentation, the activation of caspases, and the induction of histone acetylation. In conclusion, thalidomide dithiocarbamate analog 3 and thalidomide dithioate analog 5 are promising anti-cancer agents more than thalidomide.     

Hydrogen peroxide-induced expression of the proto-oncogenes, c-jun, c-fos and c-myc in rabbit lens epithelial cells

The involvement of H2O2 in cataract development has been established inboth human patients and animal models. At the molecular level H2O2 has beenobserved to cause damage to DNA, protein and lipid. To explore the oxidativestress response of the lens system at the gene expression level, we haveexamined the effects of H2O2 on the mRNA change of the proto-oncogenes,c-jun, c-fos and c-myc in a rabbit lens cell line, N/N1003A. H2O2 treatmentof the rabbit lens epithelial cells for 60 min induces quick up-regulationof both c-jun and c-fos mRNAs. The maximal induction is 38 fold for c-jun at150 µM and 72 fold for c-fos at 250 µM H2O2. Treatment ofN/N1003A cells with 50-250 µM H2O2 for 60 min leads to a 2-5 foldincrease of the c-myc mRNA level. H2O2 also induces an up-regulation intransactivity of the activating protein-1 (AP-1) as shown with a reportergene driven by a prolactin gene promoter with 4 copies of AP-1 binding sitesinserted in the upstream of the promoter. Maximal induction occurs with 150µM H2O2. In the same system, the antioxidants, N-acetyl-cysteine (NAC)and pyrrolidine dithiocarbamate (PDTC) at concentrations shown toup-regulate the mRNAs of both c-jun and c-fos, also enhance thetransactivity of AP-1. NAC and PDTC have different effects in modulating theinduction of AP-1 activity by H2O2 and TPA. These results reveal thatoxidative stress regulates expression of various regulatory genes in lenssystems, which likely affects cell proliferation, differentiation andviability and thus affect normal lens functions.     

Ultrastructural and histological study of degenerative changes in the antennal glands, hepatopancreas, and midgut of grass shrimp exposed to two dithiocarbamate biocides

The histological and ultrastructural alterations observed in the antennal glands, hepatopancreas, and midgut of grass shrimp exposed to either a 50% potassium dimethyldithiocarbamate biocide (Busan-85; 5–60 ppb) for 14 days, or to a different biocide, composed of 15% sodium dimethyldithiocarbamate and 15% disodium ethylene bisdithiocarbamate (Aquatreat DNM-30), for 3–4 days (60–140 ppb) and 28–35 days (40–120 ppb), were compared and contrasted with the normal morphological features in control shrimp. Only those experimental shrimp that exhibited various degrees of branchial abnormality were examined. Although the alterations in Busan-exposed shrimp were generally more pronounced, the antennal glands of 32 out of 36 experimental shrimp exhibited abnormalities that were manifested primarily as increased secretory activity by the labyrinth cells. In dithiocarbamate-exposed shrimp with “black gills”, the labyrinth epithelium exhibited moderate nuclear hypertrophy, apparent cell sloughing, intense secretory activity, and occasional melanized lesions; alterations in the antennal gland coelomosac included nuclear pyknosis, a general deterioration of podocyte organization, and an unusual increase in hemolymph density adjacent to affected tissues. Although there was an apparent increase in mitotic activity in the hepatopancreatic tubules of shrimp exposed to Aquatreat for 28–35 days, degenerative changes were most frequent and extensive in the hepatopancreas and midgut of dithiocarbamate-exposed shrimp with “black gills”. These observed changes included the diminution of the basal midgut and hepatopancreatic tubular system, moderate midgut hypertrophy, pronounced activity by the hepatopancreatic fixed phagocytes, development of mitochondrial inclusions and megamitochondria, loss of cytoplasmic density, hepatopancreatic nuclear pyknosis, and irreversible degeneration of hepatopancreatic tubule apices. This study suggests that some of the observed abnormal/pathological changes are the indirect consequence of branchial degeneration. A number of possible defensive reactions to dithiocarbamate poisoning, including heterostasis, phagocytosis, encapsulation, and the possible participation of reserve inclusion cells are proposed.