Ethyl pyruvate ameliorates acute respiratory distress syndrome in mice.

Acute respiratory distress syndrome (ARDS) became a focus of intensive research due to its death toll during the Covid-19 pandemic. An uncontrolled and excessive inflammatory response mediated by proinflammatory molecules such as high mobility group box protein 1 (HMGB1), IL-6, and TNF mounts as a response to infection. In this study, ethyl pyruvate (EP), a known inhibitor of HMGB1, was tested in the model of murine ARDS induced in C57BL/6 mice by intranasal administration of polyinosinic:polycytidylic acid (poly(I:C)). Intraperitoneal administration of EP ameliorated the ARDS-related histopathological changes in the lungs of poly(I:C)-induced ARDS and decreased numbers of immune cells in the lungs, broncho-alveolar lavage fluid and draining lymph nodes (DLN). Specifically, fewer CD8+ T cells and less activated CD4+ T cells were observed in DLN. Consequently, the lungs of EP-treated animals had fewer damage-inflicting CD8+ cells and macrophages. Additionally, the expression and production of proinflammatory cytokines, IL-17, IFN-γ and IL-6 were downregulated in the lungs. The expression of chemokine CCL5 which recruits immune cells into the lungs was also reduced. Finally, EP downregulated the expression of HMGB1 in the lungs. Our results imply that EP should be further evaluated as a potential candidate for ARDS therapy.

Phenethyl ester of rosmarinic acid ameliorates experimental autoimmune encephalomyelitis.

Rosmarinic acid is a polyphenolic compound, abundantly present in herbs of the Lamiaceae family. The aim of the study was to evaluate the immunomodulatory properties of a recently developed phenethyl ester derivative of rosmarinic acid (PERA), with enhanced ability of diffusion through biological membranes, in an animal model of the central nervous system (CNS) autoimmunity. To this end, experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis was used. Daily subcutaneous administration of PERA (30 mg/kg) from day 7 to day 22 after immunization successfully ameliorated EAE induced in Dark Agouti rats, shortening the disease duration and reducing maximal, cumulative and mean clinical score. PERA efficiently reduced production of major encephalitogenic cytokines, interferon (IFN)-γ and interleukin (IL)-17, in immune cells from the CNS or the lymph nodes draining the site of immunization of EAE rats, as well as in CD4+ T cells purified from the lymph nodes. Also, PERA inhibited NO production in the CNS and the lymph nodes, as well as in macrophages and microglial cells. Finally, microglial ability to produce pro-inflammatory cytokines IL-6, and tumor necrosis factor (TNF) were also reduced by PERA. Our results clearly imply that PERA possesses anti-encephalitogenic properties. Thus, further studies on the relevance of the observed effects for the therapy of multiple sclerosis are warranted.

Benfotiamine Reduces Dendritic Cell Inflammatory Potency.

BACKGROUND: Benfotiamine is a synthetic liposoluble derivative of vitamin B1 that has been shown to have anti-inflammatory properties. OBJECTIVE: To study the effects of benfotiamine on dendritic cells. METHODS: Dendritic cells were obtained from murine bone marrow precursor cells in the presence of GM-CSF. Benfotiamine was applied to the cell culture during the process of bone marrow cell differentiation into dendritic cells. Dendritic cells were stimulated with lipopolysaccharide (LPS) and expression of MHC class II molecules and CD86 was determined by flow cytometry, while levels of tumor necrosis factor (TNF) and interleukin (IL)-1ß in cell culture supernatants were measured by ELISA. F-Actin, NF-κB and Nrf2 were visualized by immunofluorescent staining and microscopy. RESULTS: Benfotiamine potently reduced LPS-induced expression of MHC class II molecules and CD86, in addition to suppressing the release of pro-inflammatory cytokines TNF and IL-1ß. It also prevented LPS-imposed morphological changes of dendritic cells, i.e. enlargement and intensified protrusions. The effects were paralleled with the reduction of NF-κB translocation to the nucleus, but not of Nrf2 activation inhibition. CONCLUSION: Having in mind the importance of dendritic cells for the configuration of the immune response, our results imply that benfotiamine has the ability to regulate the immune response through inhibition of inflammatory properties of dendritic cells.

The H2S Donor GYY4137 Stimulates Reactive Oxygen Species Generation in BV2 Cells While Suppressing the Secretion of TNF and Nitric Oxide.

GYY4137 is a hydrogen sulfide (H2S) donor that has been shown to act in an anti-inflammatory manner in vitro and in vivo. Microglial cells are among the major players in immunoinflammatory, degenerative, and neoplastic disorders of the central nervous system, including multiple sclerosis, Parkinson's disease, Alzheimer's disease, and glioblastoma multiforme. So far, the effects of GYY4137 on microglial cells have not been thoroughly investigated. In this study, BV2 microglial cells were stimulated with interferon-gamma and lipopolysaccharide and treated with GYY4137. The agent did not influence the viability of BV2 cells in concentrations up to 200 µM. It inhibited tumor necrosis factor but not interleukin-6 production. Expression of CD40 and CD86 were reduced under the influence of the donor. The phagocytic ability of BV2 cells and nitric oxide production were also affected by the agent. Surprisingly, GYY4137 upregulated generation of reactive oxygen species (ROS) by BV2 cells. The effect was mimicked by another H2S donor, Na2S, and it was not reproduced in macrophages. Our results demonstrate that GYY4137 downregulates inflammatory properties of BV2 cells but increases their ability to generate ROS. Further investigation of this unexpected phenomenon is warranted.

The elimination of P-glycoprotein over-expressing cancer cells by antimicrobial cationic peptide NK-2: the unique way of multi-drug resistance modulation.

Most chemotherapeutics harm normal cells causing severe side effects and induce the development of resistance in cancer cells. Antimicrobial peptides (AMPs), recognized as anti-cancer agents, may overcome these limitations. The most studied mechanism underlying multi-drug resistance (MDR) is the over-expression of cell membrane transporter P-glycoprotein (P-gp), which extrudes a variety of hydrophobic drugs. Additionally, P-gp contributes to cell membrane composition and increases the net negative charge on cell surface. We postulated that NK-lysin derived cationic peptide NK-2 might discriminate and preferentially eliminate P-gp over-expressing cancer cells. To test this hypothesis, we employed MDR non-small cell lung carcinoma (NCI-H460/R) and colorectal carcinoma (DLD1-TxR) cell lines with high P-gp expression. MDR cancer cells that survived NK-2 treatment had decreased P-gp expression and were more susceptible to doxorubicin. We found that NK-2 more readily eliminated P-gp high-expressing cells. Acting in 'carpet-like' manner NK-2 co-localized with P-gp on the MDR cancer cell membrane. The inhibition of P-gp reduced the NK-2 effect in MDR cancer cells and, vice versa, NK-2 decreased P-gp transport activity. In conclusion, NK-2 could modulate MDR in unique way, eliminating the P-gp high-expressing cells from heterogeneous cancers and making them more vulnerable to classical drug treatment.

Novel methylene modified cyclohexyl ethylenediamine-N,N'-diacetate ligands and their platinum(IV) complexes. Influence on biological activity.

This paper focuses on the synthesis, characterization and biological activity of new N,N'-methylene modified cyclohexyl ethylenediamine-N,N'-diacetate (edda)-type ligands and their Pt(IV) complexes. Both the ligands and complexes were characterized by infrared, UV-vis, ESI-MS, 1D ((1)H, (13)C, (195)Pt) and 2D (COSY, HSQC, HMBC) NMR spectroscopy and elemental analysis. The possible correlation between the reduction potentials and the cytotoxicity of the complexes was examined. The potential antitumoral activity of all compounds was tested in vitro on human melanoma A375, human glioblastoma U251, human prostate cancer PC3, human colon cancer HCT116, mouse melanoma B16 and mouse colon cancer CT26CL25 cells, as well as primary fibroblasts and keratinocytes. The results obtained revealed strong antitumor potential of the newly synthesized drugs with preserved efficacy against cisplatin resistant lines and less toxicity towards nonmalignant counterparts. The mechanism found to be responsible for the observed tumoricidal action of each synthesized compound was induction of apoptosis generally accompanied with caspase activation. Taken together, the effective response to the treatment of a wide range of different cell lines, including cisplatin resistant subclones, as well as induction of apoptosis, as the mechanism suggested to be the most desirable way of eliminating malignant cells, represents a great advantage of this novel group of drugs in comparison to other members in this metallo-drug family.