Random forest and live single-cell metabolomics reveal metabolic profiles of human macrophages upon polarization

Human macrophages are innate immune cells with diverse, functionally distinct phenotypes, namely, pro-inflammatory M1 and anti-inflammatory M2 macrophages. Both are involved in multiple physiological and pathological processes, including would healing, infection, and cancer. However, the metabolic differences between these phenotypes are largely unexplored at single-cell resolution. To address this knowledge gap, an untargeted live single-cell mass spectrometry-based metabolomic profiling coupled with a machine-learning data analysis approach was developed to investigate the metabolic profile of each phenotype at the single-cell level. Results show that M1 and M2 macrophages have distinct metabolic profiles, with differential levels of fatty acyls, glycerophospholipids, and sterol lipids, which are important components of plasma membrane and involved in multiple biological processes. Furthermore, we could discern several putatively annotated molecules that contribute to inflammatory response of macrophages. The combination of random forest and live single-cell metabolomics provided an in-depth profile of the metabolome of primary human M1 and M2 macrophages at the single-cell level for the first time, which will pave the way for future studies targeting the differentiation of other immune cells.     

Impact of peroxisome proliferator activated receptor agonist drugs in a model of nephrotoxicity in rats

Doxorubicin (DOX) is one of the basic anticancer drugs, nonetheless its use is restricted due to noxious side effects. Kidney failure is one of the main side effects that restrict its medical use. The current study assessed the nephroprotective effects of fenofibrate and pioglitazone against the renal injury induced by doxorubicin in rats and illustrated the probable mechanisms underlying these protective effects. For this purpose, Male Sprague–Dawley rats weighing (200–230 g) were allocated into seven groups treated for 15 days as following: control (50% corn oil + 50% DMSO p.o), fenofibrate (100 mg/kg p.o) and pioglitazone (10 mg/kg p.o) as well as four groups of DOX (15 mg/kg i.p on 11th day). DOX groups included DOX alone and DOX with protective drugs fenofibrate, pioglitazone or both of them. As a result of doxorubicin nephrotoxicity; serum creatinine and blood urea nitrogen were remarkably elevated. Moreover, renal glutathione was significantly reduced while tissue lipid peroxidation malondialdehyde, tumor necrosis factor-α, nuclear factor-kappa B p65 (NF-κB p65), interleukin-1β, p38 mitogen activated protein kinase (p38-MAPK) and caspase-3 (Casp-3) were significantly augmented. Treatment with fenofibrate and pioglitazone either alone or in combination markedly attenuated DOX-induced injury by suppression of oxidative stress, inflammation and apoptosis. The above-mentioned biochemical markers were affirmed by histological assessment. In conclusion, fenofibrate, pioglitazone, and their combination possess potential prophylactic effects against doxorubicin-induced renal injury through modulation of p38-MAPK/NF-κB p65 pathway with superiority to the combination.     

Determination of Kainic Acid-Induced Release of Nitric Oxide Using a Novel Hemoglobin Trapping Technique with Microdialysis

We have demonstrated the usefulness of a novel hemoglobin-trapping technique to quantify nitric oxide (NO) concentrations in vivo. Concentric microdialysis probes were implanted into the hippocampus of rats under urethane anesthesia and perfused with 1 μM oxyhemoglobin in artificial CSF to sequester NO in extracellular fluid. The concentration of methemoglobin was then determined spectrophotometrically. The basal level of NO in hippocampus was 2.2 ± 0.5 nM(in vitro sensitivity of the probe was 0.2 nM). Administration of 13 mg/kg, i.p., of kainic acid (KA) produced a maximal 5.3-fold increase at 100 min in NO levels (11.8 ± 0.2 nM). This response was significantly attenuated by pretreatment with the NO synthase inhibitor N-monomethyl-L-arginine (50 mg/kg, 30 min before KA). These results demonstrate that a microdialysis probe using a novel hemoglobin-trapping technique possesses adequate sensitivity to determine the basal levels of NO and document the ability of KA to increase these levels via a NO synthase-mediated mechanism.     

Fluorescence in situ hybridisation of multiple probes on a single microscope slide.

We report a method to analyse multiple samples by fluorescence in situ hybridisation on a single glass microscope slide. Wells were formed in which independent hybridisation reactions could proceed by sealing a silicon rubber gasket to the slide. In the largest format tested, different probes were hybridised simultaneously by applying them directly from a 96-well microtitre dish which was inverted on a glass plate. This technique will increase the rate of analysis of multiple probes against a standard set of chromosomes and could also be used to analyse different karyotypes using a panel of probes such as single chromosome paints during a single operation. It should be useful for both chromosomal mapping projects and screening for chromosome abnormalities in clinical diagnostic laboratories.     

The linkage map of sheep Chromosome 6 compared with orthologous regions in other species

The genetic linkage map of sheep Chromosome (Chr) 6 has been extended to include 35 loci with the addition of 11 RFLP and 12 microsatellite loci. The sex-averaged linkage map now spans 154 cM from phosphodiesterase cyclic GMP beta polypeptide (PDE6B) to OarCP125, an anonymous sheep microsatellite. The male and female map lengths, at 180 cM and 132 cM respectively, did not differ significantly. The physical assignment of PDE6B to Chr 6q33-qter orientates the linkage map on sheep Chr 6 with PDE6B near the telomere and OarCP125 towards the centromere. The order and genetic distances between loci are similar for the sheep Chr 6 and cattle Chr 6 maps, except for the position of the casein genes. The sheep Chr 6 linkage map is also comparable to portions of human Chr 4, mouse Chrs 5 and 3, and pig Chr 8. The synteny between sheep Chr 6 and human Chr 4 has been extended from PDE6B (4p16.3) to epidermal growth factor (EGF, 4q25-q27). However, a region from platelet-derived growth factor receptor α polypeptide (PDGFRA) to bone morphogenetic protein 3 (BMP3), which spans 19 cM on sheep Chr 6, appears to be inverted with respect to the human and mouse loci. Other differences in the gene order between sheep, pig, and mouse suggest more complex rearrangements. Received: 16 August 1995 / Accepted: 12 December 1995     

The basic fibroblast growth factor-saporin mitotoxin acts through the basic fibroblast growth factor receptor.

We have confirmed the hypothesis that a mitotoxin resulting from the conjugation of basic fibroblast growth factor and saporin exerts its cytotoxic effect through specific interaction with the basic fibroblast growth factor (FGF) receptor. Accordingly, the mitotoxin stimulates tyrosine phosphorylation of the 90 kD substrate that characterizes the initial cellular response to basic FGF. Cross-linking experiments show that radio-labeled basic fibroblast growth factor-saporin (FGF-SAP) binds to the receptor. Suramin, an inhibitor of growth factor receptor binding, inhibits the cytotoxicity of basic FGF-SAP. In a study of 4 different cell types, there is a decrease in the ED50 of the mitotoxin as the receptor number per cell increases. We have verified the cytotoxicity of the mitotoxin in 3 different assay systems. As expected, it is effective in the inhibition of protein synthesis and DNA synthesis, as well as of cell count. Binding of basic FGF-SAP which will result in cytotoxicity occurs very rapidly; 5 minutes of incubation of 10 nM basic FGF-SAP with cells results in 80% inhibition of cell count. The in vitro data indicate that the basic FGF-SAP is a receptor specific and potent suicide antagonist of basic FGF. Its potential as an anti-FGF for therapeutic and research uses in vivo is discussed.     

Serial natriuretic response to atrial peptide in preascitic bile duct ligated dogs

We determined if nine precirrhotic unanaesthetized dogs with chronic bile duct ligation (CBDL) responded uniformly to atrial natriuretic peptide (ANF) by infusing this peptide sequentially over 8-12 weeks at 175 ng.kg-1.min-1 and observing the natriuretic response. ANF was administered every 2 weeks post-CBDL until the 8th week and given again during the cirrhotic phase with ascites present (10-12 weeks post-CBDL). Sodium balance studies were conducted at similar time intervals. During the control period and at weeks, 2, 6, and 8 post-CBDL all dogs responded to ANF with a significant change in sodium excretion (delta UNaV, 50-240 mu equiv./min). At these times, all dogs were in sodium balance. At week 4 and during the ascitic period, heterogeneity of response to ANF was observed. In the former interval, five dogs responded (delta UNaV,75-230 mu equiv./min) and four did not, while in the latter interval, five dogs responded (delta UNaV, 50-240 mu equiv./min) and three did not (one dog died). In both time periods, there was severe urinary sodium retention (daily UNaV, 11 +/- 3 and 2 +/- 1 mequiv./day, respectively) while the dogs were ingesting 45 mequiv.Na+/day. The heterogeneity of natriuretic response was not correlated to plasma immunoreactive ANF, renin, or aldosterone levels. Plasma volume was significantly expanded from control during both intervals. We conclude that there is transient sodium retention during the 4th week post-CBDL, and that this period is associated with the heterogeneity of natriuretic response to ANF, despite the absence of ascites or edema.