Effect of metabolic factors on macrophage activation and inactivation

Obesity constitutes an important risk factor for the development of metabolic syndrome and a variety of other obesity-related pathologic conditions. Obesity induces a chronic low grade metabolic inflammation.Macrophages are important mediators of inflammatory responses and metabolic factors directly act on their function. They can be polarized either towards a pro-inflammatory, M1 phenotype or an anti-inflammatory, M2 phenotype depending on their environmental stimuli. In the present study we investigated the effect of insulin resistance on macrophage activitιον. For this purpose we employed macrophages that acquired insulin resistance, being macrophages exposed to high insulin concentrations either in vitro or in vivo in a mouse model of high-fat diet induced insulin resistance, as well as macrophages that lack Akt2 isoform or Insulin-like growth factor 1 receptor (Igf1R). These macrophages showed impaired insulin signaling, while the Akt1/mTORC1 pathway was activated at the basal levels. Insulin resistant macrophages obtained an M2-like phenotype, termed M-InsR, and displayed a metabolic shift towards glycolysisSubsequently, in order to investigate the contribution of insulin resistant macrophages in acute inflammatory responses, an in vivo model of polymicrobial sepsis in wild type, diet-induced obese, Akt2-/- and LysMCreIgf1Rfl/fl mice. We found that both inflammation and lung injury were significantly milder in mice harboring insulin resistant macrophages. Finally, M-InsR macrophages have an important role in sustained inflammatory responses, since they can shape microbial composition of the gut irrespective of the diet.This study describes a kind of innate immune memory in peripheral macrophages characterized by an M2-like phenotype, which is under the control of Akt1/mTORC1 signals and glycolytic metabolism. This phenotype may explain the changes in macrophage responses and development of related pathologic conditions that occur in obesity.Η παχυσαρκία αποτελεί ένα σημαντικό προδιαθεσικό παράγοντα για την ανάπτυξη του μεταβολικού συνδρόμου και μιας πληθώρας άλλων σχετιζόμενων με την παχυσαρκία παθολογικών καταστάσεων. Η παχυσαρκία προκαλεί μια χρόνια χαμηλού βαθμού μεταβολική φλεγμονή.Τα μακροφάγα αποτελούν σημαντικούς διαμεσολαβητές των φλεγμονωδών αποκρίσεων και μεταβολικοί παράγοντες μπορούν να επηρεάσουν τη λειτουργία τους. Ανάλογα με τα περιβαλλοντικά ερεθίσματα μπορούν να μεταβάλλουν την ενεργοποίησή τους είτε προς μια προφλεγμονώδη, Μ1-τύπου ή προς μία αντιφλεγμονώδη, Μ2-τύπου κατάσταση ενεργοποίησης.Στην παρούσα μελέτη μελετήθηκε η επίδραση της αντίστασης στην ινσουλίνη στην ενεργοποίηση των μακροφάγων. Για το σκοπό αυτό χρησιμοποιήσαμε μακροφάγα με αντίσταση στην ινσουλίνη, όπως μακροφάγα τα οποία εκτέθηκαν σε υψηλές συγκεντρώσεις ινσουλίνης είτε στην καλλιέργεια είτε απομονώθηκαν από ποντίκια που ανέπτυξαν αντίσταση στην ινσουλίνη λόγω δίαιτας, όπως επίσης και μακροφάγα με έλλειψη στην κινάση Akt2 ή έλλειψη του υποδοχέα IGF1. Στα μακροφάγα αυτά βρέθηκε σημαντικά μειωμένη επαγωγή της σηματοδότησης της ινσουλίνης, ενώ σε βασικά επίπεδα εμφάνισαν αυξημένη ενεργοποίηση του Akt1/mTORC1 μονοπατιού. Τα μακροφάγα με αντίσταση στην ινσουλίνη (M-InsR), απέκτησαν μία Μ2-τύπου ενεργοποίηση και αυξημένη γλυκόλυση. Στη συνέχεια, για τη μελέτη της συμβολής των M-InsR στις οξείες φλεγμονώδεις αποκρίσεις, χρησιμοποιήθηκε ένα μοντέλο πολυμικροβιακής σήψης σε ποντίκια αγρίου τύπου, παχύσαρκα λόγω πρόσληψης δίαιτας υψηλής σε λιπάρα, με έλλειψη στην Akt2 κινάση και με έλλειψη του IGF1 μόνο από τα μακροφάγα. Τόσο η φλεγμονή, όσο και η ιστική βλάβη ήταν σημαντικά ηπιότερη στα ποντίκια που έφεραν μακροφάγα με αντίσταση στην ινσουλίνη. Τέλος, τα M-InsR μακροφάγα μπορούν έχουν σημαντικό ρόλο και στις εμμένουσες φλεγμονώδεις αποκρίσεις, διαμορφώνοντας τη σύσταση του μικροβιώματος. Η παρούσα μελέτη περιγράφει την ανάπτυξη ενός είδους μνήμης στα περιφερικά μακροφάγα κατά την παχυσαρκία, η οποία χαρακτηρίζεται από ένα Μ2-τύπου φαινότυπο ενεργοποίησης, ο οποίος βρίσκεται υπό τον έλεγχο της σηματοδότησης του μονοπατιού Akt1/mTORC1 και της γλυκόλυσης. Ο φαινότυπος αυτός ίσως εξηγεί τις διαφορετικές αποκρίσεις των μακροφάγων καθώς και την ανάπτυξη παθολογικών καταστάσεων που εμφανίζονται κατά την παχυσαρκία

Evaluation of HSP70 deficiency in the inflammatory response in vivo and in vitro: The impact of HSP90 expression, glucocorticoid release, and glutamine administration

The present study aimed to explore the pathway through which Heat Shock Protein 70 (HSP70) is involved in inflammation and sepsis and the possible interaction with glutamine, an essential nutrient during sepsis. We also evaluated the possible interaction of HSP70 with HSP90, another HSP involved in sepsis. Therefore, we utilized mice with specific deletion of the Hsp70.1 and Hsp70.3 genes (Hsp70-/-) and their wild type littermates (Hsp70+/+) for the in vivo studies and primary macrophages collected from Hsp70+/+ and Hsp70-/- mice for the in vitro studies. We found that HSP70 deficiency was associated with lower inflammatory cytokine levels in plasma and lung tissue and increased levels of glucocorticoid secretion during inflammation in vivo. On the contrary, Hsp70-/- murine peritoneal macrophages showed increased inflammatory response compared to Hsp70+/+ macrophages, following LPS stimulation. Glutamine administration repressed the in vivo secretion of plasma cytokines from Hsp70-/- mice while enhanced the in vitro secretion of cytokines from macrophages of the same genotype (Hsp70-/-), but it did not affect the secretion of cytokines from wild type mice either in vivo or in vitro, following LPS treatment. Our data also demonstrated that HSP70 deficiency was associated with increased glucocorticoid release, in vivo. In vitro, pre-treatment of macrophages from both genotypes with HSP90 inhibitor significantly attenuated IL-6 secretion only from Hsp70-/- cells, following LPS treatment. In summary, in vivo, the lack of HSP70 leads to an anti-inflammatory phenotype, while in vitro, the lack of HSP70 in macrophages gives rise to a proinflammatory phenotype, which may be mediated by the HSP90. Both in vivo and in vitro, glutamine treatment responses in Hsp70-/- mice suggest alternative pathways bypassing HSP70

An IL-10/DEL-1 axis supports granulopoiesis and survival from sepsis in early life

Abstract The limited reserves of neutrophils are implicated in the susceptibility to infection in neonates, however the regulation of neutrophil kinetics in infections in early life remains poorly understood. Here we show that the developmental endothelial locus (DEL-1) is elevated in neonates and is critical for survival from neonatal polymicrobial sepsis, by supporting emergency granulopoiesis. Septic DEL-1 deficient neonate mice display low numbers of myeloid-biased multipotent and granulocyte-macrophage progenitors in the bone marrow, resulting in neutropenia, exaggerated bacteremia, and increased mortality; defects that are rescued by DEL-1 administration. A high IL-10/IL-17A ratio, observed in newborn sepsis, sustains tissue DEL-1 expression, as IL-10 upregulates while IL-17 downregulates DEL-1. Consistently, serum DEL-1 and blood neutrophils are elevated in septic adult and neonate patients with high serum IL-10/IL-17A ratio, and mortality is lower in septic patients with high serum DEL-1. Therefore, IL-10/DEL-1 axis supports emergency granulopoiesis, prevents neutropenia and promotes sepsis survival in early life

Impact of add-back FSH on human and mouse prostate following gonadotropin ablation by GnRH antagonist treatment

Objective: During androgen ablation in prostate cancer by the standard gonadotropin-releasing hormone (GnRH) agonist treatment, only luteinizing hormone (LH) is permanently suppressed while circulating follicle-stimulating hormone (FSH) rebounds. We explored direct prostatic effects of add-back FSH, after androgen ablation with GnRH antagonist, permanently suppressing both gonadotropins. Methods: The effects of recombinant human (rFSH) were examined in mice treated with vehicle (controls), GnRH antagonist degarelix (dgx), dgx + rFSH, dgx + flutamide, or dgx + rFSH + flutamide for 4 weeks. Prostates and testes size and expression of prostate-specific and/or androgen-responsive genes were measured. Additionally, 33 young men underwent dgx-treatment. Seventeen were supplemented with rFSH (weeks 1–5), and all with testosterone (weeks 4–5). Testosterone, gondotropins, prostate-specific antigen (PSA), and inhibin B were measured. Results: In dgx and dgx + flutamide treated mice, prostate weight/body weight was 91% lower than in controls, but 41 and 11%, respectively, was regained by rFSH treatment (P = 0.02). The levels of seminal vesicle secretion 6, Pbsn, Nkx3.1, beta-microseminoprotein, and inhibin b were elevated in dgx + rFSH-treated animals compared with only dgx treated (all P < 0.05). In men, serum inhibin B rose after dgx treatment but was subsequently suppressed by testosterone. rFSH add-back had no effect on PSA levels. Conclusions: These data provide novel evidence for the direct effects of FSH on prostate sizand gene expression in chemically castrated mice. However, in chemically castrated men, FSH had no effect on PSA production. Whether FSH effects on the prostate in humans also require suppression of the residual adrenal-derived androgens and/or a longer period of rFSH stimulation, remains to be explored

Novel Wild-Type <i>Pediococcus</i> and <i>Lactiplantibacillus</i> Strains as Probiotic Candidates to Manage Obesity-Associated Insulin Resistance

As the food and pharmaceutical industry is continuously seeking new probiotic strains with unique health properties, the aim of the present study was to determine the impact of short-term dietary intervention with novel wild-type strains, isolated from various sources, on high-fat diet (HFD)-induced insulin resistance. Initially, the strains were evaluated in vitro for their ability to survive in simulated gastrointestinal (GI) conditions, for adhesion to Caco-2 cells, for bile salt hydrolase secretion, for cholesterol-lowering and cellular cholesterol-binding ability, and for growth inhibition of food-borne pathogens. In addition, safety criteria were assessed, including hemolytic activity and susceptibility to antibiotics. The in vivo test on insulin resistance showed that mice receiving the HFD supplemented with Pediococcus acidilactici SK (isolated from human feces) or P. acidilactici OLS3-1 strain (isolated from olive fruit) exhibited significantly improved insulin resistance compared to HFD-fed mice or to the normal diet (ND)-fed group