The Effect of Low‐Intensity Exercise Training on Fat Metabolism of Obese Women

Objective: Previous studies have shown that fat metabolism is different in upper body (UB) and lower body (LB) obese women. The present study investigated whether the effect of low‐intensity exercise training on fat metabolism is different in UB and LB obese premenopausal women. Research Methods and Procedures: Twenty‐one healthy, premenopausal women with either LB obesity (waist‐to‐hip ratio of ≤0.79; n = 8) or UB obesity (waist‐to‐hip ratio of ≥0.85; n = 13) participated in the present study. The UB obese women were matched and randomly divided in an exercise training group (UB) and a nonexercising control group (UB‐C). Subjects in the UB and LB groups participated in a low‐intensity exercise training program (40% Vo ₂max) three times per week for 12 weeks. Before and after the intervention, measurements of fat metabolism at rest and during exercise, body composition, and maximal aerobic capacity were performed. Results: Exercise training did not change the respiratory exchange ratio at rest in the UB and LB groups. During exercise, relative fat oxidation increased in the UB group by 19% (p < 0.05), whereas no change in the LB and UB‐C groups was found. Plasma free fatty acid oxidation did not change by exercise training, and nonplasma fatty acid oxidation tended to increase in the UB group compared with the UB‐C group (p = 0.08). Discussion: Low‐intensity exercise training increased the contribution of fat oxidation to total energy expenditure during exercise but not at rest in UB obese women. Exercise training had no significant effect on fat metabolism in the LB obese women.     

High-performance liquid chromatography of nalbuphine, butorphanol and morphine in blood and brain microdialysate samples: application to pharmacokinetic/pharmacodynamic studies in rats

A rapid and sensitive assay for quantification of nalbuphine, butorphanol and morphine in blood (50 microL) and brain microdialysate ( approximately 40 microL) samples was developed. Blood samples were extracted with ethyl acetate. Analysis was performed with high-performance liquid chromatography (HPLC) coupled to an electrochemical detector. The mobile phase was a mixture of 0.1 M sodium phosphate buffer, methanol and octane-sulfonic acid with ratio and pH depending on compound and matrix. The limits of quantification in blood samples were 25, 50 and 25 ng/mL for nalbuphine, butorphanol and morphine, respectively and 0.5 ng/mL for morphine in microdialysate samples. Based on sample volume, sensitivity and reproducibility, these assays are particularly suitable for pharmacokinetic/pharmacodynamic studies in rodents.     

Serum metabolomics profile of type 2 diabetes mellitus in a Brazilian rural population

Introduction

The development of common forms of diabetes comes from the interaction between environmental and genetic factors, and the consequences of poor glycemic control in these patients could result in several complications. Metabolomic studies for type 2 diabetes mellitus in serum/plasma have reported changes in numerous metabolites, which might be considered possible targets for future mechanistic research. However, the specific role of a particular metabolite as cause or consequence of diabetes derangements is difficult to establish.

Objectives

As type 2 diabetes is a disease that changes the metabolic profile in several levels, this work aimed to compare the metabolomic profiles of type 2 diabetes mellitus and non-diabetic participants. In addition, we exploited our family-based study design to bring a better understanding of the causal relationship of identified metabolites and diabetes.

Methods

In the current study, population based metabolomics was applied in 939 subjects from the Baependi Heart Study. Participants were separated into two groups: diabetic (77 individuals) and non-diabetic (862 individuals), and the metabolic profile was performed by GC/MS technique.

Results

We have identified differentially concentrated metabolites in serum of diabetic and non-diabetic individuals. We identified 72 metabolites up-regulated in type 2 diabetes mellitus compared to non-diabetics. It was possible to recapitulate the main pathways that the literature shows as changed in diabetes. Also, based on metabolomic profile, we separated pre-diabetic individuals (with glucose concentration between 100–125 mg/dL) from non-diabetics and diabetics. Finally, using heritability analysis, we were able to suggest metabolites in which altered levels may precede diabetic development.

Conclusion

Our data can be used to derive a better understanding of the causal relationship of the observed associations and help to prioritize diabetes-associated metabolites for further work.

     

LRRK2 at the interface of autophagosomes,endosomes and lysosomes

Over the past 20 years, substantial progress has been made in identifying the underlying genetics of Parkinson’s disease (PD). Of the known genes, LRRK2 is a major genetic contributor to PD. However, the exact function of LRRK2 remains to be elucidated. In this review, we discuss how familial forms of PD have led us to hypothesize that alterations in endomembrane trafficking play a role in the pathobiology of PD. We will discuss the major observations that have been made to elucidate the role of LRRK2 in particular, including LRRK2 animal models and high-throughput proteomics approaches. Taken together, these studies strongly support a role of LRRK2 in vesicular dynamics. We also propose that targeting these pathways may not only be beneficial for developing therapeutics for LRRK2-driven PD, but also for other familial and sporadic cases.     

The Allelochemical MDCA Inhibits Lignification and Affects Auxin Homeostasis

The phenylpropanoid 3,4-(methylenedioxy)cinnamic acid (MDCA) is a plant-derived compound first extracted from roots of Asparagus officinalis and further characterized as an allelochemical. Later on, MDCA was identified as an efficient inhibitor of 4-COUMARATE-CoA LIGASE (4CL), a key enzyme of the general phenylpropanoid pathway. By blocking 4CL, MDCA affects the biosynthesis of many important metabolites, which might explain its phytotoxicity. To decipher the molecular basis of the allelochemical activity of MDCA, we evaluated the effect of this compound on Arabidopsis thaliana seedlings. Metabolic profiling revealed that MDCA is converted in planta into piperonylic acid (PA), an inhibitor of CINNAMATE-4-HYDROXYLASE (C4H), the enzyme directly upstream of 4CL. The inhibition of C4H was also reflected in the phenolic profile of MDCA-treated plants. Treatment of in vitro grown plants resulted in an inhibition of primary root growth and a proliferation of lateral and adventitious roots. These observed growth defects were not the consequence of lignin perturbation, but rather the result of disturbing auxin homeostasis. Based on DII-VENUS quantification and direct measurement of cellular auxin transport, we concluded that MDCA disturbs auxin gradients by interfering with auxin efflux. In addition, mass spectrometry was used to show that MDCA triggers auxin biosynthesis, conjugation, and catabolism. A similar shift in auxin homeostasis was found in the c4h mutant ref3-2, indicating that MDCA triggers a cross talk between the phenylpropanoid and auxin biosynthetic pathways independent from the observed auxin efflux inhibition. Altogether, our data provide, to our knowledge, a novel molecular explanation for the phytotoxic properties of MDCA.Plants growing in a tight community are in continuous competition for space, light, water, and nutrients. Potential survival strategies include optimizing plant architecture and maximizing growth rate, allowing the plant to capture light and receive nutrients and water more efficiently, while placing neighboring plants in an unfavorable position (Einhellig, 1995; Weir et al., 2004). Besides developmental shifts, plants release an array of secondary metabolites (allelochemicals) into the rhizosphere to negatively affect the growth and reproduction of neighboring, competitor plants (Putnam, 1988; Bertin et al., 2003). Despite a lot of research effort having been devoted to allelopathic chemical warfare over the past decades, it remains a difficult study object due to the complexity of plant-plant interactions (Zeng, 2014). Nevertheless, the significance of allelochemicals in structuring plant communities and preserving biodiversity has been fully recognized by the scientific community. Moreover, allelochemicals show the potential to be used as an environmentally friendly alternative for weed control to improve agricultural productivity (Zeng, 2014).Strictly speaking, the term “allelochemical” refers to a compound produced and released by one organism to affect the growth and development of susceptible species (Weir et al., 2004). In practice, compounds derived from plant extracts or exudates are often cataloged as allelochemicals based on their inhibitory effect on seed germination and/or growth of other plant species in an artificial setup. Despite their importance, the molecular mode of action of a given allelochemical compound has rarely been studied in detail; however, toxicity is relatively easily demonstrated, identifying its molecular target is far more challenging. An interesting example is the phenylpropanoid 3,4-(methylenedioxy)cinnamic acid (MDCA), which was isolated from lyophilized root tissues of Asparagus [Asparagus officinalis L.; Hartung et al. (1990)]. It was suggested to be an allelochemical based on its inhibitory effect on root and shoot growth of Lepidium sativum (Hartung et al., 1990). Independent studies revealed that MDCA acts as an efficient competitive inhibitor of 4-COUMARATE-CoA LIGASE (4CL), the enzyme converting hydroxycinnamates to their corresponding CoA-esters (Knobloch and Hahlbrock, 1977; Chakraborty et al., 2009). This conversion is an early step in the general phenylpropanoid pathway leading to a wide array of metabolites, including coumarins, stilbenes, salicylic acid, flavonoids, and monolignols (Vogt, 2010). Given that inhibition of 4CL in this metabolic pathway will have far-reaching effects on plant growth and development (Voelker et al., 2010), it is tempting to link the proposed phytotoxicity of MDCA to this metabolic block.Here, we evaluate whether the phytotoxicity of MDCA is a direct consequence of the inhibition of 4CL or if MDCA targets also other biological processes in Arabidopsis (Arabidopsis thaliana). We found that MDCA causes strong developmental defects in Arabidopsis seedlings at early developmental stages. Convincing evidence was found that MDCA affects the homeostasis of the plant signaling compound auxin. Our results provide an alternative explanation for the molecular mechanism underlying the phytotoxic properties of MDCA, and suggest that these multiple modes of action make it an attractive candidate as an environmental agrochemical or synergist.     

Tracking plant preference for higher‐quality mycorrhizal symbionts under varying CO2 conditions over multiple generations

The symbiosis between plants and root‐colonizing arbuscular mycorrhizal (AM) fungi is one of the most ecologically important examples of interspecific cooperation in the world. AM fungi provide benefits to plants; in return plants allocate carbon resources to fungi, preferentially allocating more resources to higher‐quality fungi. However, preferential allocations from plants to symbionts may vary with environmental context, particularly when resource availability affects the relative value of symbiotic services. We ask how differences in atmospheric CO₂‐levels influence root colonization dynamics between AMF species that differ in their quality as symbiotic partners. We find that with increasing CO₂‐conditions and over multiple plant generations, the more beneficial fungal species is able to achieve a relatively higher abundance. This suggests that increasing atmospheric carbon supply enables plants to more effectively allocate carbon to higher‐quality mutualists, and over time helps reduce lower‐quality AM abundance. Our results illustrate how environmental context may affect the extent to which organisms structure interactions with their mutualistic partners and have potential implications for mutualism stability and persistence under global change.     

Discovery of selective 2,4-diaminoquinazoline toll-like receptor 7 (TLR 7) agonists

The discovery of a novel series of highly potent quinazoline TLR 7/8 agonists is described. The synthesis and structure–activity relationship is presented. Structural requirements and optimization of this series toward TLR 7 selectivity afforded the potent agonist 48. Pharmacokinetic and pharmacodynamic studies highlighted 48 as an orally available endogenous interferon (IFN-α) inducer in mice.     

Monitoring of cell therapy and assessment of cardiac function using magnetic resonance imaging in a mouse model of myocardial infarction

We have developed a mouse severe combined immunodeficient (SCID) model of myocardial infarction based on permanent coronary artery occlusion that allows long-term functional analysis of engrafted human embryonic stem cell-derived cardiomyocytes, genetically marked with green fluorescent protein (GFP), in the mouse heart. We describe methods for delivery of dissociated cardiomyocytes to the left ventricle that minimize scar formation and visualization and validation of the identity of the engrafted cells using the GFP emission spectrum, and histological techniques compatible with GFP epifluorescence, for monitoring phenotypic changes in the grafts in vivo. In addition, we describe how magnetic resonance imaging can be adapted for use in mice to monitor cardiac function non-invasively and repeatedly. The model can be adapted to include multiple control or other cell populations. The procedure for a cohort of six mice can be completed in a maximum of 13 weeks, depending on follow-up, with 30 h of hands-on time.