Elamipretide Promotes Mitophagosome Formation and Prevents Its Reduction Induced by Nutrient Excess in INS1 β-cells

Elamipretide is a tetrapeptide that restores defects in mitochondrial function, binds to cardiolipin, and is being tested in clinical trials for mitochondria-related diseases. However, whether elamipretide modulates mitochondrial quality control and dynamics, processes essential to preserve mitochondrial function, is unclear. Thus, we tested the effects of elamipretide on mitochondrial morphology, mitophagosome formation, and their early disruption induced by excess nutrients in INS1 β-cells. Elamipretide treatment was sufficient to increase engulfment of mitochondria into autophagosomes in control INS1 β-cells, without inducing widespread changes in mitochondrial morphology or membrane potential. In an early pathogenic context mimicked by short-term exposure to nutrient excess, elamipretide treatment prevented both mitochondrial fragmentation and defects in the engulfment of mitochondria into autophagosomes. On the other hand, elamipretide did not prevent lysosomal defects induced by nutrient excess. Accordingly, elamipretide treatment did not entail benefits on pathogenic p62 and LC3II accumulation or on insulin secretory function. In conclusion, our data show that elamipretide selectively stimulates the engulfment of mitochondria into autophagosomes and prevents its defects induced by nutrient excess. Thus, we propose that improved selectivity of mitochondrial quality control processes might contribute to the benefits stemming from elamipretide treatments in other disease models.     

Structure-based design,synthesis, and biological evaluation of imidazo[1,2-b]pyridazine-based p38 MAP kinase inhibitors

We identified novel potent inhibitors of p38 MAP kinase using structure-based design strategy. X-ray crystallography showed that when p38 MAP kinase is complexed with TAK-715 (1) in a co-crystal structure, Phe169 adopts two conformations, where one interacts with 1 and the other shows no interaction with 1. Our structure-based design strategy shows that these two conformations converge into one via enhanced protein-ligand hydrophobic interactions. According to the strategy, we focused on scaffold transformation to identify imidazo[1,2-b]pyridazine derivatives as potent inhibitors of p38 MAP kinase. Among the herein described and evaluated compounds, N-oxide 16 exhibited potent inhibition of p38 MAP kinase and LPS-induced TNF-α production in human monocytic THP-1 cells, and significant in vivo efficacy in rat collagen-induced arthritis models. In this article, we report the discovery of potent, selective and orally bioavailable imidazo[1,2-b]pyridazine-based p38 MAP kinase inhibitors with pyridine N-oxide group.     

Evaluation of the mass transfer rate using computer simulation in a three-dimensional interwoven hollow fiber-type bioartificial liver

Objectives

To determine the most efficient design of a hollow fiber-based bioreactor device for a bioartificial liver support system through comparative bioengineering evaluations.

Results

We compared two types of hollow fiber-based bioreactors, the interwoven-type bioreactor (IWBAL) and the dialyzer-type bioreactor (DBAL), by evaluating the overall mass transfer coefficient (K) and the convective coefficient (X). The creatinine and albumin mass transfer coefficients and convective coefficients were calculated using our mathematical model based on the homoporous theory and the modified Powell method. Additionally, using our model, we simulated the mass transport efficiency in clinical-scale BALs. The results of this experiment demonstrate that the mass transfer coefficients for creatinine and albumin increased proportionally with velocity with the IWBAL, and were consistently greater than that found with the DBAL. These differences were further enhanced in the simulation of the large-scale model.

Conclusions

Our findings indicate that the IWBAL with its unique 30° cross hollow fiber design can provide greater solute removal and more efficient metabolism when compared to the conventional DBAL design.

     

Zinc oxide nanoparticles-mediated changes in ultrastructure and macromolecules of pomegranate callus cells

The dramatic increase in the usage of nanoparticles (NPs) in a variety of applications extensively expanded the possibility regarding the release of NPs into our ecosystem. Pomegranate is a tropical and subtropical countries’ shrub, as offers food supplement and more pharmaceutical and medicinal applications. Here, we investigated the effects concerning different concentrations regarding each of ZnO NPs and its bulk on growth, uptake of Zn, potassium (K), phosphorus (P), proline, ascorbic acid, total phenolic compounds, total antioxidant, localization of Zn in callus cells by transmission electron microscope (TEM) and changes in macromolecules by Fourier transform infrared spectroscopy (FT-IR) in pomegranate (Punica granatum cv. Hegazy) callus. Growth parameters in callus exposure to high concentrations of ZnO (50–200 µg mL^?1) were reduced. Different concentrations of ZnO NPs and bulk did not affect the content of K and P. In comparison according to control, uptake of Zn was increased in pomegranate callus exposed to both ZnO NPs and its bulk. Moreover, TEM images showed small cells with the tortuous cell wall, disintegrated cytoplasmic content and Zn deposition in the cell walls at low concentration of ZnO NPs. However, the high concentration of ZnO NPs showed a further Zn influx in the cytoplasm and attachment to the tonoplast. The FT-IR analysis confirmed variations in the peaks corresponding to the most macromolecules, phenolic compounds, lipids, proteins, carbohydrates, cellulose, and hemicellulose. From these results, we could consider the toxicity effects concerning ZnO NPs and its bulk.     

Homology between surface protein antigen genes of Streptococcus sobrinus and Streptococcus mutans

The structural gene (pag gene) for a 210 kDa protein antigen of Streptococcus sobrinus serotype g was cloned and compared with that (pac gene) of a 190 kDa protein antigen of Streptococcus mutans serotype c. Immunodiffusion analysis revealed that the product of the pag gene immunologically cross-reacted with that of the pac gene. Southern blot and nucleotide sequence analyses revealed that a significant homology existed between the middle regions of the two structural genes.     

Clq enhancement of IgG-dependent eosinophil-mediated killing of schistosomula in vitro

Antibody-dependent eosinophil-mediated cytotoxicity plays a role in host protection against metazoan parasite invasion. We examined a possible role for Clq in eosinophil-mediated cytotoxicity by using a Schistosoma mansoni schistosomula killing system in vitro. The addition of monomeric purified human Clq enhanced IgG-dependent human eosinophil-mediated killing from 1.4-fold to 2.3-fold (mean percent killing 12% +/- 4 vs 21% +/- 4, p less than 0.005) when the immune IgG concentration was low. In contrast, there was no significant enhancement of neutrophil-mediated killing. When the IgG concentration was increased fourfold Clq did not cause enhancement of eosinophil-mediated killing (35% +/- 9 vs 37% +/- 5). Preincubation of eosinophils with type 1 collagen abrogated Clq enhancement of killing, raising the possibility of a receptor-mediated process, which depends upon cellular binding of Clq via the collagenous portion of the molecule. Eosinophils and neutrophils were examined for the presence of Clq receptors by using 125I labeled Clq. Clq binding to both cell types was saturable, reversible, and specific, indicating that binding is through specific receptors. Type 1 collagen inhibited binding of Clq to cells, suggesting that Clq binding is via the collagenous stalk of Clq. The number of receptors was approximately twice as high for eosinophils as compared with neutrophils (1.9 X 10(7) vs 1.1 X 10(7), p less than 0.025). Affinity constants for the two cell types were similar (1.5 X 10(7) vs 1.3 X 10(7). These findings suggest that Clq and receptors for Clq on eosinophils may be important for eosinophil-mediated schistosomula killing.