Impact of interleukin-6 on the glucose metabolic capacity in rat liver

miR-378 affects metabolic disturbances in the mdx model of Duchenne muscular dystrophy

Although Duchenne muscular dystrophy (DMD) primarily affects muscle tissues, the alterations to systemic metabolism manifested in DMD patients contribute to the severe phenotype of this fatal disorder. We propose that microRNA-378a (miR-378) alters carbohydrate and lipid metabolism in dystrophic mdx mice. In our study, we utilized double knockout animals which lacked both dystrophin and miR-378 (mdx/miR-378^-/-). RNA sequencing of the liver identified 561 and 194 differentially expressed genes that distinguished mdx versus wild-type (WT) and mdx/miR-378^-/- versus mdx counterparts, respectively. Bioinformatics analysis predicted, among others, carbohydrate metabolism disorder in dystrophic mice, as functionally proven by impaired glucose tolerance and insulin sensitivity. The lack of miR-378 in mdx animals mitigated those effects with a faster glucose clearance in a glucose tolerance test (GTT) and normalization of liver glycogen levels. The absence of miR-378 also restored the expression of genes regulating lipid homeostasis, such as Acly, Fasn, Gpam, Pnpla3, and Scd1. In conclusion, we report for the first time that miR-378 loss results in increased systemic metabolism of mdx mice. Together with our previous finding, demonstrating alleviation of the muscle-related symptoms of DMD, we propose that the inhibition of miR-378 may represent a new strategy to attenuate the multifaceted symptoms of DMD.

Protective efficacy of combined trivalent inactivated ISA 71 oil adjuvant vaccine against avian influenza virus subtypes (H9N2 and H5N1) and Newcastle disease virus

AIM

The objective of the present study was to prepare a trivalent inactivated vaccine of Newcastle disease virus (NDV), H5N1, and H9N2 viruses.

MATERIALS AND METHODS

Three monovalent and a trivalent vaccines were prepared by emulsifying inactivated NDV (LaSota strain), reassortant H5N1, and H9N2 viruses with Montanide ISA 71 oil adjuvant. Parameters used for evaluation of the efficacy of the prepared vaccines in specific pathogen-free chickens were cellular immunity assays (blastogenesis, interferon gamma, interleukin 1 [IL1], and IL6), humoral immunity by hemagglutination inhibition, protection percentage, and shedding.

RESULTS

A single immunization with trivalent vaccine-enhanced cell-mediated immunity as well as humoral immune response with 90% protection against challenges with highly pathogenic avian influenza (HPAI) H5N1 and low pathogenic (LP) avian influenza H9N2 viruses with 100% protection after challenge with NDV.

CONCLUSION

Development and evaluation of the trivalent vaccine in the study reported the success in preparation of a potent and efficacious trivalent vaccine which is a promising approach for controlling HPAI H5N1, LP H9N2, and ND viral infections.

Preparation of mucosal nanoparticles and polymer-based inactivated vaccine for Newcastle disease and H9N2 AI viruses

AIM

To develop a mucosal inactivated vaccines for Newcastle disease (ND) and H9N2 viruses to protect against these viruses at sites of infections through mucosal immunity.

MATERIALS AND METHODS

In this study, we prepared two new formulations for mucosal bivalent inactivated vaccine formulations for Newcastle and Avian Influenza (H9N2) based on the use of nanoparticles and polymer adjuvants. The prepared vaccines were delivered via intranasal and spray routes of administration in specific pathogen-free chickens. Cell-mediated and humoral immune response was measured as well as challenge trial was carried out. In addition, ISA71 water in oil was also evaluated.

RESULTS

Our results showed that the use of spray route as vaccination delivery method of polymer and nanoparticles Montanide™ adjuvants revealed that it enhanced the cell mediated immune response as indicated by phagocytic activity, gamma interferon and interleukin 6 responses and induced protection against challenge with Newcastle and Avian Influenza (H9N2) viruses.

CONCLUSION

The results of this study demonstrate the potentiality of polymer compared to nanoparticles adjuvantes when used via spray route. Mass application of such vaccines will add value to improve the vaccination strategies against ND virus and Avian influenza viruses.

Dysfunctional muscle and liver glycogen metabolism in mdx dystrophic mice

Background

Duchenne muscular dystrophy (DMD) is a severe, genetic muscle wasting disorder characterised by progressive muscle weakness. DMD is caused by mutations in the dystrophin (dmd) gene resulting in very low levels or a complete absence of the dystrophin protein, a key structural element of muscle fibres which is responsible for the proper transmission of force. In the absence of dystrophin, muscle fibres become damaged easily during contraction resulting in their degeneration. DMD patients and mdx mice (an animal model of DMD) exhibit altered metabolic disturbances that cannot be attributed to the loss of dystrophin directly. We tested the hypothesis that glycogen metabolism is defective in mdx dystrophic mice.

Results

Dystrophic mdx mice had increased skeletal muscle glycogen (79%, (P<0.01)). Skeletal muscle glycogen synthesis is initiated by glycogenin, the expression of which was increased by 50% in mdx mice (P<0.0001). Glycogen synthase activity was 12% higher (P<0.05) but glycogen branching enzyme activity was 70% lower (P<0.01) in mdx compared with wild-type mice. The rate-limiting enzyme for glycogen breakdown, glycogen phosphorylase, had 62% lower activity (P<0.01) in mdx mice resulting from a 24% reduction in PKA activity (P<0.01). In mdx mice glycogen debranching enzyme expression was 50% higher (P<0.001) together with starch-binding domain protein 1 (219% higher; P<0.01). In addition, mdx mice were glucose intolerant (P<0.01) and had 30% less liver glycogen (P<0.05) compared with control mice. Subsequent analysis of the enzymes dysregulated in skeletal muscle glycogen metabolism in mdx mice identified reduced glycogenin protein expression (46% less; P<0.05) as a possible cause of this phenotype.

Conclusion

We identified that mdx mice were glucose intolerant, and had increased skeletal muscle glycogen but reduced amounts of liver glycogen.

[Macroglobulin signaling system]

This review will focus on the systematization of knowledge about structure of macroglobulin signaling system, which includes macroglobulin family proteins (alpha-2-macroglobulin, alpha-2-glycoprotein, pregnancy associated plasma protein A), their receptors (LRP, grp78), ligands (proteinases, cytokines, hormones, lipids, et al.) transforming and transcriptional factors for regulation of macroglobulins synthesis. After reviewing the functions of macroglobulin signaling system, and mechanisms of their realization, we discuss the complex and significant role of this system in different physiological and pathological processes.

[Genetic profiles of longevity and healthy cognitive aging in nonagenarians from the Basque Country]

INTRODUCTION

Currently there are notable differences in the aging of individuals in modern populations. While some of them enjoy a long healthy aging, others develop neurodegenerative diseases, such as Alzheimer's disease (AD). Environmental factors are critical, but genetics could explain the differences observed. It has recently been postulated that longevity genes might also be neuroprotective.

OBJECTIVES

To assess whether certain genetic variants associated with longevity might have a neuroprotective effect.

METHODS

The subjects of this study are people older than 90 years. We will collect sociodemographic and clinical data and multiple assessments, cognitive, functional, anthropometric, nutritional, sensory and physical each participant. In addition, 64 SNPs loci distributed in 13 candidate genes FOXO3, SIRT1, TOMM40, APOE, PICALM, COMT, CETP, CLU, CR1, IL-6, PCK-1, ZNF224 and ACE will be analysed by Taqman array.

RESULTS

It is hoped to gain more knowledge about under/over-represented alleles in nonagenarians. Furthermore, comparison of the genetic characteristics of nonagenarians with AD with those free of disease will enable links to be seen between certain alleles with protection or the risk of AD. Associated information on the participants will create subgroups showing the interactions between environment and genetic variation in relation to healthy aging and AD.

CONCLUSION

The study of the genetic variability of nonagenarians can give us information on the alleles associated with longevity and neuroprotection.

Early hepatocyte DNA synthetic response posthepatectomy is modulated by IL-6 trans-signaling and PI3K/AKT activation

BACKGROUND & AIMS

Interleukin-6 (IL-6) is a crucial factor in liver regeneration following partial hepatectomy (PH); however, the role of IL-6 and IL-6 trans-signaling in particular, in hepatocyte mitosis remains controversial. IL-6 trans-signaling relies upon the release of the soluble IL-6R (sIL-6R), which binds IL-6 to form an agonistic IL-6/sIL-6R complex. Herein we have examined the hypothesis that IL-6 trans-signaling plays a crucial and distinct role in liver regeneration following PH.

METHODS

The specific IL-6/sIL-6R antagonist, sgp130Fc, was expressed in mice and analyzed for its effect on hepatocyte mitosis following PH. Alternatively, we examined the effect of the IL-6/sIL-6R super-agonist, Hyper-IL-6, or IL-6 expressed either alone or in combination with hepatocyte growth factor (HGF) on hepatocyte mitosis in the absence of PH.

RESULTS

Following PH, the dramatic rise of circulating IL-6 levels is accompanied by a concurrent ∼2-fold increase in circulating sIL-6R levels. Ectopic expression of sgp130Fc reduced hepatocyte mitosis by about 40% at early times following PH, while substantially reducing AKT, but not STAT3, activation. But, ectopic Hyper-IL-6 expression in mice without PH was not mitogenic to hepatocytes in vivo. Rather, Hyper-IL-6, but not IL-6, markedly increased HGF-induced hepatocyte mitosis. This cooperative effect correlated with greater resistance of HIL-6 than IL-6 to HGF-mediated reduction of AKT activation, rather than changes in STAT3 or MAPK signaling, and was completely blocked by PI3K inhibition.

CONCLUSIONS

Following PH, IL-6/sIL-6R cooperates with growth factors, through a PI3K/AKT-dependent mechanism to promote entry of hepatocytes into the cell cycle.

IL-6 deficiency in mice neither impairs induction of metabolic genes in the liver nor affects blood glucose levels during fasting and moderately intense exercise

AIMS/HYPOTHESIS

Fasting and exercise are strong physiological stimuli for hepatic glucose production. IL-6 has been implicated in the regulation of gluconeogenic genes, but the results are contradictory and the relevance of IL-6 for fasting- and exercise-induced hepatic glucose production is not clear.

METHODS

Investigations were performed in rat hepatoma cells, and on C57Bl6 and Il6(-/-) mice under the following conditions: IL-6 stimulation/injection, non-exhaustive exercise (60 min run on a treadmill) and fasting for 16 h. Metabolite analysis, quantitative real-time PCR and immunoblotting were performed.

RESULTS

IL-6 stimulation of rat hepatoma cells led to higher glucose production. Injection of IL-6 in mice slightly increased hepatic Pepck (also known as Pck1) expression. Fasting of Il6(-/-) mice for 16 h did not alter glucose production compared with wild-type mice, since plasma glucose concentrations were similar and upregulation of phosphoenolpyruvate carboxykinase (PEPCK) and Pgc-1alpha (also known as Ppargc1a) expression was comparable. In the non-fasting state, Il6(-/-) mice showed a mild metabolic alteration including higher plasma glucose and insulin levels, lower NEFA concentrations and slightly increased hepatic PEPCK content. Moderately intense exercise resulted in elevated IL-6 plasma levels in wild-type mice. Despite that, plasma glucose, insulin, NEFA levels and hepatic glycogen content were not different in Il6(-/-) mice immediately after running, while expression of hepatic G6pc, Pgc-1alpha, Irs2 and Igfbp1 mRNA was similarly increased.

CONCLUSIONS/INTERPRETATION

These data suggest that in mice IL-6 is not essential for physiologically increased glucose production during fasting or non-exhaustive exercise.

Recent progress in histochemistry

The progress in discerning the structure and function of cells and tissues in health and disease has been achieved to a large extent by the continued development of new reagents for histochemistry, the improvement of existing techniques and new imaging techniques. This review will highlight some advancements made in these fields.