Mitochondrial peptide Mtln contributes to oxidative metabolism in mice.

Mitoregulin (Mtln) is a recently identified 56 amino acid long mitochondrial peptide conserved in vertebrates. Mtln is known to enhance function of respiratory complex I, which is likely mediated by modulation of lipid composition. To address an influence of Mtln gene on the metabolism we created knockout mice deficient in Mtln gene. In line with accumulation of triglycerides observed earlier on a model of Mtln knockout cell lines, we observed Mtln KO mice to develop obesity on a high fat diet. An increased weight gain could be attributed to enhanced fat accumulation according to the magnetic resonance live imaging. In addition, Mtln KO mice demonstrate elevated serum triglycerides and other oxidation substrates accompanied by an exhaustion of tricarboxylic acids cycle intermediates, suggesting suboptimal oxidation of respiration substrates by mitochondria lacking Mtln.

Chronic bladder catheterization for precise urine collection in awake mice.

Metabolic chambers are routinely used for urine collection in rodents. In mice, due to small urination volume, evaporation in the metabolic chambers (≈50%) distorts diuresis and urinalysis parameters. We have developed a new technique of bladder catheterization enabling long-term accurate and contamination-free urine collection in awake male and female mice for 30 days or longer. Daily diuresis in catheterized mice was twice higher as compared to metabolic cages. The twofold difference in urine recovery was preserved when the circadian variation of diuresis, the effects of furosemide, desmopressin and water load were estimated using the two techniques. Urine osmolarity, urinalysis, and microbiological parameters evidence higher quality of the catheter-collected urine. Using phenol red, we demonstrate utility of our technique for pharmacokinetic studies. 30 days after the surgery the catheters were patent and had minimal impact on the animals' heath. Bladder catheterization is a useful tool for physiological, pharmacological, and toxicological studies.

Gene Expression Pattern of Peyer's Patch Lymphocytes Exposed to Kagocel Suggests Pattern-Recognition Receptors Mediate Its Action.

Kagocel is a synthetic carboxymethylcellulose derivative copolymerized with gossypol. Clinical data evidence its safety and efficiency for the treatment of flu and other viral infections via enhancement of interferon production. The gut-associated lymphoid tissue seems a likely site of kagocel action. The study was aimed to investigate the molecular mechanisms of its action using murine Peyer's patches lymphocytes as a test system and the cytokines production and gene expression patterns as the primary outcomes. The Peyer's patches lymphocytes isolated from BALB/c mice were stimulated with concanavalin A, or, to mimic viral infection, with a combination of concanavalin A and TLR3 ligand poly I:C. After 24 h of stimulation the cells were treated with saline, 30, 100, or 300 µg/ml of kagocel, or, as positive controls, 300 µg/ml oats b-D-glucan or 300 µg/ml lentinan. After 24 and 72 h of incubation with these drugs cytokines production was analyzed with ELISA and gene expression pattern was investigated using nCounter Inflammation panel chips followed by bioinformatics analysis. Expression of genes involved in the inflammatory response, antiviral defense, lymphocytes survival and proliferation (C1qa, C2, C3, Ccl21a, Il11, Il1b, Il23a, Il5, Ltb4r2, Alox15, Pla2g4a, Ptger1, Mapkapk5, Hras, Ifna1, Tlr2, Mrc1, Mx2) was upregulated in kagocel-treated Peyer's patches lymphocytes. A list of plausible transcription factors (CEBPs, IRF, NFκB, RXR, Stat, Tead4, and ZSCAN) and master-regulators has been identified (cIAP, CIKS, dock9, MEKK1, FXR, IKK, IRAK, TRAF, dsRNA:TLR3:TRIF). The changes in gene expression pattern and the outcomes of bioinformatics analysis suggest that pattern recognition receptors, TLRs and dectin-1, are the key mediators of kagocel immunomodulatory action, with the possible involvement of interferon autocrine loop. The genes upregulated with kagocel include diverse components of the innate immune defense system.

Effects of Superoxide Dismutase Inhibitors and Glucose on Cell Death and Generation of Reactive Oxygen Species in Pea Leaves.

The effects of superoxide dismutase (SOD) inhibitors, diethyldithiocarbamate (DDC), triethylenetetramine (trien), and their combination with glucose on cells of the epidermis from pea leaves of different age (rapidly growing young leaves and slowly growing old leaves) was investigated. DDC and trien caused death of the guard cells as determined by destruction of their nuclei. Glucose did not affect destruction of the nuclei induced by SOD inhibitors in the cells from old leaves, but intensified it in the cells from young leaves. 2-Deoxyglucose, an inhibitor of glycolysis, and propyl gallate, SOD-mimic and antioxidant, suppressed destruction of the nuclei that was caused by SOD inhibitors and glucose in cells of the epidermis from the young, but not from the old leaves. Glucose and trien stimulated, and propyl gallate reduced generation of reactive oxygen species (ROS) in the pea epidermis as determined by the fluorescence of 2',7'-dichlorofluorescein (DCF). Carbonyl cyanide m-chlorophenylhydrazone (CCCP), a protonophoric uncoupler of oxidative and photosynthetic phosphorylation, suppressed the DCF fluorescence in the guard cells. Treatment of the cells with CCCP followed by its removal with washing increased destruction of the nuclei caused by SOD inhibitors and glucose. In young leaves, CCCP was less effective than in old ones. The findings demonstrate the effects of SOD inhibitors and glucose on the cell death and generation of ROS and could indicate glycolysis-dependent ROS production.

Role of the leader sequence in tobacco pectin methylesterase secretion.

We report that unprocessed tobacco pectin methylesterase (PME) contains N-terminal pro-sequence including the transmembrane (TM) domain and spacer segment preceding the mature PME. The mature portion of PME was replaced by green fluorescent protein (GFP) gene and various deletion mutants of pro-sequence fused to GFP were cloned into binary vectors and agroinjected in Nicotiana benthamiana leaves. The PME pro-sequence delivered GFP to the cell wall (CW). We showed that a transient binding of PME TM domain to endoplasmic reticulum membranes occurs upon its transport to CW. The CW targeting was abolished by various deletions in the TM domain, i.e., anchor domain was essential for secretion of GFP to CW. By contrast, even entire deletion of the spacer segment had no influence on GFP targeting.