Fever-like temperature impacts on Staphylococcus aureus and Pseudomonas aeruginosa interaction, physiology, and virulence both in vitro and in vivo.

BACKGROUND: Staphylococcus aureus (SA) and Pseudomonas aeruginosa (PA) cause a wide variety of bacterial infections and coinfections, showing a complex interaction that involves the production of different metabolites and metabolic changes. Temperature is a key factor for bacterial survival and virulence and within the host, bacteria could be exposed to an increment in temperature during fever development. We analyzed the previously unexplored effect of fever-like temperatures (39 °C) on S. aureus USA300 and P. aeruginosa PAO1 microaerobic mono- and co-cultures compared with 37 °C, by using RNAseq and physiological assays including in vivo experiments. RESULTS: In general terms both temperature and co-culturing had a strong impact on both PA and SA with the exception of the temperature response of monocultured PA. We studied metabolic and virulence changes in both species. Altered metabolic features at 39 °C included arginine biosynthesis and the periplasmic glucose oxidation in S. aureus and P. aeruginosa monocultures respectively. When PA co-cultures were exposed at 39 °C, they upregulated ethanol oxidation-related genes along with an increment in organic acid accumulation. Regarding virulence factors, monocultured SA showed an increase in the mRNA expression of the agr operon and hld, pmsα, and pmsß genes at 39 °C. Supported by mRNA data, we performed physiological experiments and detected and increment in hemolysis, staphyloxantin production, and a decrease in biofilm formation at 39 °C. On the side of PA monocultures, we observed an increase in extracellular lipase and protease and biofilm formation at 39 °C along with a decrease in the motility in correlation with changes observed at mRNA abundance. Additionally, we assessed host-pathogen interaction both in vitro and in vivo. S. aureus monocultured at 39οC showed a decrease in cellular invasion and an increase in IL-8-but not in IL-6-production by A549 cell line. PA also decreased its cellular invasion when monocultured at 39 °C and did not induce any change in IL-8 or IL-6 production. PA strongly increased cellular invasion when co-cultured at 37 and 39 °C. Finally, we observed increased lethality in mice intranasally inoculated with S. aureus monocultures pre-incubated at 39 °C and even higher levels when inoculated with co-cultures. The bacterial burden for P. aeruginosa was higher in liver when the mice were infected with co-cultures previously incubated at 39 °C comparing with 37 °C. CONCLUSIONS: Our results highlight a relevant change in the virulence of bacterial opportunistic pathogens exposed to fever-like temperatures in presence of competitors, opening new questions related to bacteria-bacteria and host-pathogen interactions and coevolution.

Are silymarin and N-acetylcysteine able to prevent liver damage mediated by multiple factors? Findings against ethanol plus LPS-induced liver injury in mice.

This study investigated the effect of N-acetylcysteine (NAC) and silymarin (SIL) in the liver of mice exposed to ethanol and lipopolysaccharides (LPS). Mice were divided into four groups (n = 6): naive, vehicle, NAC (200 mg/kg), and SIL (200 mg/kg). Treatments were given orally (po) once daily for 10 days. Liver injury was induced by administration of ethanol (30%, po) for 10 days, once daily, followed by a single administration of LPS (2 mg/kg, ip) 24 h before euthanasia. After the treatment period, animals were euthanized, and liver and blood samples were collected. NAC, but not SIL, prevented the increase in oxalacetic glutamic transaminase (OGT) and pyruvic glutamic transaminase (PGT) serum levels. NAC and SIL did not restore levels of reduced glutathione or hepatic malonaldehyde. The treatments with NAC or SIL showed no difference in the activity of glutathione S-transferase, superoxide dismutase, and catalase compared to vehicle group. Myeloperoxidase and N-acetylglucosaminidase activities are increased, as well as the IL-6 and IL-10 levels in the liver. The treatment with NAC, but not SIL, reduced the N-acetylglucosamines activity and the IL-6 and IL-10 amount in the liver. Histological findings revealed microsteatosis in the vehicle group, which was not prevented by SIL but was partially reduced in animals receiving NAC. Unlike other liver injury models, NAC (200 mg/kg) or SIL (200 mg/kg) did not positively affect antioxidant patterns in liver tissue of animals exposed to ethanol plus LPS, but NAC treatment displays anti-inflammatory properties in this model.

Leishmania braziliensis exosomes activate human macrophages to produce proinflammatory mediators.

Exosomes, organelles measuring 30-200nm, are secreted by various cell types. Leishmania exosomes consist of many proteins, including heat shock proteins, annexins, Glycoprotein 63, proteins exerting signaling activity and those containing mRNA and miRNA. Studies have demonstrated that Leishmania donovani exosomes downregulate IFN-γ and inhibit the expression of microbicidal molecules, such as TNF and nitric oxide, thus creating a microenvironment favoring parasite proliferation. Despite lacking immunological memory, data in the literature suggest that, following initial stimulation, mononuclear phagocytes may become "trained" to respond more effectively to subsequent stimuli. Here we characterized the effects of macrophage sensitization using L. braziliensis exosomes prior to infection by the same pathogen. Human macrophages were stimulated with L. braziliensis exosomes and then infected with L. braziliensis. Higher levels of IL-1ß and IL-6 were detected in cultures sensitized prior to infection compared to unstimulated infected cells. Moreover, stimulation with L. braziliensis exosomes induced macrophage production of IL-1ß, IL-6, IL-10 and TNF. Inhibition of exosome secretion by L. braziliensis prior to macrophage infection reduced cytokine production and produced lower infection rates than untreated infected cells. Exosome stimulation also induced the consumption/regulation of NLRP3 inflammasome components in macrophages, while the blockade of NLRP3 resulted in lower levels of IL-6 and IL-1ß. Our results suggest that L. braziliensis exosomes stimulate macrophages, leading to an exacerbated inflammatory state that may be NLRP3-dependent.

Myelin Disruption, Neuroinflammation, and Oxidative Stress Induced by Sulfite in the Striatum of Rats Are Mitigated by the pan-PPAR agonist Bezafibrate.

Sulfite predominantly accumulates in the brain of patients with isolated sulfite oxidase (ISOD) and molybdenum cofactor (MoCD) deficiencies. Patients present with severe neurological symptoms and basal ganglia alterations, the pathophysiology of which is not fully established. Therapies are ineffective. To elucidate the pathomechanisms of ISOD and MoCD, we investigated the effects of intrastriatal administration of sulfite on myelin structure, neuroinflammation, and oxidative stress in rat striatum. Sulfite administration decreased FluoromyelinTM and myelin basic protein staining, suggesting myelin abnormalities. Sulfite also increased the staining of NG2, a protein marker of oligodendrocyte progenitor cells. In line with this, sulfite also reduced the viability of MO3.13 cells, which express oligodendroglial markers. Furthermore, sulfite altered the expression of interleukin-1ß (IL-1ß), interleukin-6 (IL-6), interleukin-10 (IL-10), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS) and heme oxygenase-1 (HO-1), indicating neuroinflammation and redox homeostasis disturbances. Iba1 staining, another marker of neuroinflammation, was also increased by sulfite. These data suggest that myelin changes and neuroinflammation induced by sulfite contribute to the pathophysiology of ISOD and MoCD. Notably, post-treatment with bezafibrate (BEZ), a pan-PPAR agonist, mitigated alterations in myelin markers and Iba1 staining, and IL-1ß, IL-6, iNOS and HO-1 expression in the striatum. MO3.13 cell viability decrease was further prevented. Moreover, pre-treatment with BEZ also attenuated some effects. These findings show the modulation of PPAR as a potential opportunity for therapeutic intervention in these disorders.

Pre-treatment with IL-6 potentiates ß-cell death induced by pro-inflammatory cytokines.

BACKGROUND: Type I Diabetes mellitus (T1D) is characterized by a specific destruction of ß-cells by the immune system. During this process pro-inflammatory cytokines are released in the pancreatic islets and contribute for ß-cells demise. Cytokine-induced iNOS activation, via NF-κB, is implicated in induction of ß-cells death, which includes ER stress activation. Physical exercise has been used as an adjunct for better glycemic control in patients with T1D, since it is able to increase glucose uptake independent of insulin. Recently, it was observed that the release of IL-6 by skeletal muscle, during physical exercise, could prevent ß-cells death induced by pro-inflammatory cytokines. However, the molecular mechanisms involved in this beneficial effect on ß-cells are not yet completely elucidated. Our aim was to evaluate the effect of IL-6 on ß-cells exposed to pro-inflammatory cytokines. RESULTS: Pre-treatment with IL-6 sensitized INS-1E cells to cytokine-induced cell death, increasing cytokine-induced iNOS and Caspase-3 expression. Under these conditions, however, there was a decrease in cytokines-induced p-eIF2-α but not p-IRE1expression, proteins related to ER stress. To address if this prevention of adequate UPR response is involved in the increase in ß-cells death markers induced by IL-6 pre-treatment, we used a chemical chaperone (TUDCA), which improves ER folding capacity. Use of TUDCA increased cytokines-induced Caspase-3 expression and Bax/Bcl-2 ratio in the presence of IL-6 pre-treatment. However, there is no modulation of p-eIF2-α expression by TUDCA in this condition, with increase of CHOP expression. CONCLUSION: Treatment with IL-6 alone is not beneficial for ß-cells, leading to increased cell death markers and impaired UPR activation. In addition, TUDCA has not been able to restore ER homeostasis or improve ß-cells viability under this condition, suggesting that other mechanisms may be involved.

LOX-1 Activation by oxLDL Induces AR and AR-V7 Expression via NF-κB and STAT3 Signaling Pathways Reducing Enzalutamide Cytotoxic Effects.

The oxidized low-density lipoprotein receptor 1 (LOX-1) is one of the most important receptors for modified LDLs, such as oxidated (oxLDL) and acetylated (acLDL) low-density lipoprotein. LOX-1 and oxLDL are fundamental in atherosclerosis, where oxLDL/LOX1 promotes ROS generation and NF-κB activation inducing the expression of IL-6, a STAT3 activator. Furthermore, LOX-1/oxLDL function has been associated with other diseases, such as obesity, hypertension, and cancer. In prostate cancer (CaP), LOX-1 overexpression is associated with advanced stages, and its activation by oxLDL induces an epithelial-mesenchymal transition, increasing angiogenesis and proliferation. Interestingly, enzalutamide-resistant CaP cells increase the uptake of acLDL. Enzalutamide is an androgen receptor (AR) antagonist for castration-resistant prostate cancer (CRPC) treatment, and a high percentage of patients develop a resistance to this drug. The decreased cytotoxicity is promoted in part by STAT3 and NF-κB activation that induces the secretion of the pro-inflammatory program and the expression of AR and its splicing variant AR-V7. Here, we demonstrate for the first time that oxLDL/LOX-1 increases ROS levels and activates NF-κB, inducing IL-6 secretion and the activation of STAT3 in CRPC cells. Furthermore, oxLDL/LOX1 increases AR and AR-V7 expression and decreases enzalutamide cytotoxicity in CRPC. Thus, our investigation suggests that new factors associated with cardiovascular pathologies, such as LOX-1/oxLDL, may also promote important signaling axes for the progression of CRPC and its resistance to drugs used for its treatment.

Ethanol consumption favors pro-contractile phenotype of perivascular adipose tissue: A role for interleukin-6.

Perivascular adipose tissue (PVAT) exerts anticontractile effect, but under non-physiological conditions it may contribute to vascular dysfunction by releasing pro-inflammatory cytokines. Since PVAT is an important source of interleukin (IL)-6, we evaluated whether this cytokine would contribute to ethanol-induced vascular dysfunction. With this purpose, male C57BL/6 wild-type (WT) or IL-6-deficient mice (IL-6-/-) were treated with ethanol for 12 weeks. Increased blood pressure was evidenced after 4 and 6 weeks of treatment with ethanol in WT and IL-6-/- mice, respectively. In WT mice, ethanol increased plasma and PVAT levels of IL-6. Ethanol favoured pro-contractile phenotype of PVAT in mesenteric arteries from WT, but not IL-6-deficient mice. Functional studies showed that tiron [(a scavenger of superoxide (O2-)] reversed the pro-contractile effect of PVAT in mesenteric arteries from ethanol-treated mice. Ethanol increased the levels of O2- in PVAT from WT mice. Ethanol-induced increase in O2- generation was higher in arteries with PVAT from WT mice when compared to IL-6-deficient mice. Treatment with ethanol augmented myeloperoxidase activity in the mesenteric arterial bed (MAB; with or without PVAT) from WT, but not IL-6-deficient mice. In conclusion, IL-6 contributes to the pro-contractile effect of PVAT by a mechanism that involves increase in ROS generation. Additionally, IL-6 mediates intravascular recruitment of neutrophils in response to ethanol and plays a role in the early stages of ethanol-induced hypertension. Collectively, our findings provide novel evidence for a role of IL-6 in the vascular dysfunction induced by ethanol.

Inflammation reduction potential of nanostructured lipid carriers encapsulated with rat's bone marrow cells' lysate.

Bone marrow-derived mesenchymal stromal cells (BMSCs) have been used for treating inflammatory disorders. Due to the large size of BMSCs compared to nanoparticles, BMSCs cannot be loaded into the nanoparticles. It is hypothesized that BMSCs lysate loading into the nanocarriers will effectively deliver cellular contents and regulatory elements of BMSCs at the injury site. This study aimed to investigate nanostructured lipid carriers (NLC) loading with BMSCs lysate through basic characterization and morphological analysis. Moreover, this study was mainly designed to investigate the role of NLC loaded BMSCs lysate in reducing inflammation via in-vitro and in-vivoassays. The in-vitro study involves cell viability assays, p53, annexin V and VEGF expression through ELISA and immunocytochemistry, real-time BAX, caspase-3, IL-6, IL-8, TOP2A, PCNA, and Ki-67 gene expression analysis. Additionally, to evaluate in-vivo anti-inflammatory activity, the carrageenan-induced rat paw oedema model was used. In-vitro results showed that NLC loaded BMSCs lysate increased cell viability, decreased apoptosis and pro-inflammatory genes expression and up-regulated angiogenesis and proliferation in H2O2 pre-stimulated cells. Findings of the in-vivo assay also indicated a reduction in rat's paw oedema volume in NLC-loaded BMSCs lysate, and downregulation of BAX, Caspase-3, IL-6, and IL-8 was observed. Enhanced expressions of TOP2A, PCNA, and Ki-67 were obtained. Concluding the results of this study, NLC-loaded BMSCs lysate could reduce inflammation and possibly regenerate damaged tissue mainly via increasing cell viability, angiogenesis and proliferation, and reducing apoptosis and pro-inflammatory cytokines.

Influence of supplement administration of omega-3 on the subcutaneous tissue response of endodontic sealers in Wistar rats.

AIM: Natural substances such as omega-3 have been used in the medical field due to their numerous properties and, in particular, modulating effect on the systemic and local inflammatory processes. Thus, this study evaluated the influence of omega-3 supplementation on the subcutaneous tissue response of endodontic sealers in Wistar Rats. METHODOLOGY: Polyethylene tubes were implanted in the subcutaneous tissue of 48 animals (one empty for control and three filled with Sealapex, AH Plus or Endofill). The animals were treated with omega-3 (TO) or water (TW). Treatments started 15 days before implantation until euthanasia. After 5, 15 and 30 days (n = 8), animals were euthanized and polyethylene tubes and surrounding tissue were removed and processed for histological analysis. The inflammatory reaction was analysed by Haematoxylin and Eosin stain and immunolabelling for IL-6 and TNF-α. The collagen maturity was analysed by picrosirius red stain and calcium deposition by von Kossa stain and polarized light. Results were statistically analysed (p < .05). RESULTS: Amongst TW sealer groups, Endofill evoked a more intense inflammatory infiltrate compared with AH Plus and control in the 30-day period (p = .009). However, in TO sealer groups, there was no difference amongst the sealers and control in all periods (p > .05). Comparing each sealer as a function of the supplementation with water or omega-3, there are differences for Endofill (p = .001) and Sealapex (p = .005) in the 30-day period, presenting lower inflammatory infiltrate in the animals treated with omega-3. A higher percentage of immature fibres was observed at 15 and 30 days in the TO group, compared with the TW group (p < .05). The deposition of calcium particles was observed only by Sealapex in all periods, despite the supplementation procedure. CONCLUSIONS: Omega-3 supplementation influence the tissue reactions of endodontic sealers, modulating inflammation, the immunolabelling of IL-6 and TNF-α, the repair process and it does not interfere with calcium deposition.

Increased TNF-α production in response to IL-6 in patients with systemic inflammation without infection.

Acute systemic inflammation can lead to life-threatening organ dysfunction. In patients with sepsis, systemic inflammation is triggered in response to infection, but in other patients, a systemic inflammatory response syndrome (SIRS) is triggered by non-infectious events. IL-6 is a major mediator of inflammation, including systemic inflammatory responses. In homeostatic conditions, when IL-6 engages its membrane-bound receptor on myeloid cells, it promotes pro-inflammatory cytokine production, phagocytosis, and cell migration. However, under non-physiologic conditions, such as SIRS and sepsis, leucocyte dysfunction could modify the response of these cells to IL-6. So, our aim was to evaluate the response to IL-6 of monocytes from patients diagnosed with SIRS or sepsis. We observed that monocytes from patients with SIRS, but not from patients with sepsis, produced significantly more TNF-α than monocytes from healthy volunteers, after stimulation with IL-6. Monocytes from SIRS patients had a significantly increased baseline phosphorylation of the p65 subunit of NF-κB, with no differences in STAT3 phosphorylation or SOCS3 levels, compared with monocytes from septic patients, and this increased phosphorylation was maintained during the IL-6 activation. We found no significant differences in the expression levels of the membrane-bound IL-6 receptor, or the serum levels of IL-6, soluble IL-6 receptor, or soluble gp130, between patients with SIRS and patients with sepsis. Our results suggest that, during systemic inflammation in the absence of infection, IL-6 promotes TNF-α production by activating NF-κB, and not the canonical STAT3 pathway.

Effect of retained placenta and clinical mastitis on reproduction parameters, immune response, and steroidogenic receptors gene expression in postpartum crossbred dairy cows.

The purpose of this study was to evaluate the effect of retained placenta (RP) and clinical mastitis (CM) on the reproductive efficiency of crossbred dairy cows during the postpartum period and the effect in some innate immune system indicators. For this, two experiments were carried out. In the first, a total of 232 cows were evaluated and divided as: healthy control (n = 184), RP (n = 22), and CM (n = 26) groups. The RP and CM was evaluated until 30 days postpartum (DPP) and reproductive rates were measured. In experiment 2, cows were divided in control (n = 10), RP (n = 10), and CM (n = 30) groups. Between 40 and 50 DPP, clinical, gynecological examination and endometrial cytobrush were performed to evaluate subclinical endometritis (SE) and gene expression of interleukins 1ß (IL-1ß) and 6 (IL-6), chemokine ligand 5 (CCL5), estrogen α (ESR1), and progesterone (PGR) receptors by qRT-PCR analysis. In experiment 1, the conception rate at 1st artificial insemination (AI) was lower in RP and CM groups and pregnancy rate at 150 days decreased in CM group. Calving-to-1st AI interval and days open were shorter in healthy cows. In experiment 2, the occurrence of SE was 26.7% and higher in RP and CM groups. The expression of IL-1ß increased in RP and CM groups, while IL-6 was less expressed in RP group. The CCL5, ESR1, and PGR were similar between groups. In conclusion, cows with RP and CM had their reproductive efficiency negatively affected and had they initial pro-inflammatory response improved by the increase of IL-ß.

Wound-healing and cytokine-modulating potential of medicinal oil formulation comprising leaf extract of Murraya koenigii and olive oil.

The study investigated the wound healing effect of medicinal oil (MO) formulation prepared from Murraya koenigii leaves extract (methanolic) incorporated in olive oil. The MO was visually transparent, homogenous, smooth in texture, the viscosity grade was observed as 140 cP and easily spreadable. Pro-inflammatory cytokines IL-1ß, IL-6, and TNF-α were significantly reduced to 82.3 ± 3.5, 156 ± 6.2, 137.3. ± 5.5 pg/ml, respectively after treatment with MO when compared to disease control animals that showed IL-1ß, IL-6, and TNF-α levels of 170 ± 6, 265 ± 7, and 288.6 ± 11, pg/ml respectively. The level of pro-inflammatory cytokine in povidone iodine solution (PIS) group was 95.3 ± 3, 162 ± 6, 177.6 ± 8.9 pg/ml of IL-1ß, IL-6, and TNF-α respectively. Interestingly, the wound-healing efficacy of MO was found better as compared to povidone iodine treated standard group and concluded that MO has excellent wound healing effect.

Defining the Role of Anti- and Pro-inflammatory Outcomes of Interleukin-6 in Mental Health.

Interleukin-6 (IL-6) is a major cytokine that promotes anti- and pro-inflammatory outcomes by activating the membrane IL-6 receptor (IL-6R) or the soluble IL-6 receptor (sIL-6R). IL-6R and sIL-6R signaling engage the JAK1/2/3 targets and the downstream transcription of STAT1 and STAT3 family. In the brain, physiological IL-6 signaling preserves neurogenesis, neuronal differentiation, and neuroprotection against tissue injury, but IL-6 has been proposed as a biomarker for poor prognosis in several mental pathologies such as depressive disorders, schizophrenia, bipolar disorder, and autism. Physiological or pathological outcomes of IL-6 are related to its pleiotropic effects in the brain by microglia, astrocytes, neurons, and endothelial cells, and also by peripheral infiltrating macrophages or T lymphocytes. Notably, definition of anti- or pro-inflammatory profiles by IL-6 signaling in the brain are sensitive to the levels, cellular source, and targets of the IL-6 itself, as well as IL-6 receptor signaling, and its activation/inhibition ratio. We propose that a mutual IL-6 crosstalk between microglia, astrocytes, neurons, and endothelial cells defines the anti- and pro-inflammatory outcomes in the brain, modulating brain function. This review will describe the cellular, molecular and context-dependent signaling pathways that define anti- or pro-inflammatory profiles setting by IL-6 during physiological or pathological outcomes in the brain.

LPS Response Is Impaired by Urban Fine Particulate Matter.

Fine particulate matter (PM2.5) is a complex mixture of components with diverse chemical and physical characteristics associated with increased respiratory and cardiovascular diseases mortality. Our study aimed to investigate the effects of exposure to concentrated PM2.5 on LPS-induced lung injury onset. BALB/c male mice were exposed to either filtered air or ambient fine PM2.5 in an ambient particle concentrator for 5 weeks. Then, an acute lung injury was induced with nebulized LPS. The animals were euthanized 24 h after the nebulization to either LPS or saline. Inflammatory cells and cytokines (IL-1ß, IL-4, IL-5, IL-6, IL-10, IL-17, TNF) were assessed in the blood, bronchoalveolar lavage fluid (BALF), and lung tissue. In addition, lung morphology was assessed by stereological methods. Our results showed that the PM+LPS group showed histological evidence of injury, leukocytosis with increased neutrophils and macrophages, and a mixed inflammatory response profile, with increased KC, IL-6, IL-1ß, IL-4, and IL-17. Our analysis shows that there is an interaction between the LPS nebulization and PM2.5 exposure, differently modulating the inflammatory response, with a distinct response pattern as compared to LPS or PM2.5 exposure alone. Further studies are required to explain the mechanism of immune modulation caused by PM2.5 exposure.

Therapeutic effects of benzoylaconitine and paeoniflorin in rats with collagen-induced arthritis

Abstract To explore the effects and mechanisms of benzoylaconitine and paeoniflorin on collagen-induced arthritis (CIA) rats. Weight, paw swelling, arthritis index and joint pathologic changes were examined in each group after CIA induction. PGE2, IL-1ß, IL-6, IL-10, TNF-α, VEGF, MMP-3, IgG and anti-CII Ab were assessed by ELISA; STAT1 and STAT3 expressions were analyzed immunohistochemically, and the ultrastructure of synovial cells was observed by transmission electron microscopy. Therapeutic effects were determined in CIA rats via injecting benzoylaconitine and paeoniflorin, which could alleviate the degree of swelling and arthritis index (AI) and pathological lesions of the sacroiliac gland; decrease the levels of PGE2, IL-1ß, TNF-α, VEGF and IgG in serum; reduce STAT1 and STAT3 expression in the membrane tissue; and inhibit the secretion and proliferation of synovial cells. These results showed that benzoylaconitine and paeoniflorin could significantly palliate the arthritic symptoms of CIA rats, and better therapeutic effects could be achieved if the two components were used in combination

Interleukin-6 actions in the hypothalamus protects against obesity and is involved in the regulation of neurogenesis.

BACKGROUND: Interleukin-6 (IL6) produced in the context of exercise acts in the hypothalamus reducing obesity-associated inflammation and restoring the control of food intake and energy expenditure. In the hippocampus, some of the beneficial actions of IL6 are attributed to its neurogenesis-inducing properties. However, in the hypothalamus, the putative neurogenic actions of IL6 have never been explored, and its potential to balance energy intake can be an approach to prevent or attenuate obesity. METHODS: Wild-type (WT) and IL6 knockout (KO) mice were employed to study the capacity of IL6 to induce neurogenesis. We used cell labeling with Bromodeoxyuridine (BrdU), immunofluorescence, and real-time PCR to determine the expression of markers of neurogenesis and neurotransmitters. We prepared hypothalamic neuroprogenitor cells from KO that were treated with IL6 in order to provide an ex vivo model to further characterizing the neurogenic actions of IL6 through differentiation assays. In addition, we analyzed single-cell RNA sequencing data and determined the expression of IL6 and IL6 receptor in specific cell types of the murine hypothalamus. RESULTS: IL6 expression in the hypothalamus is low and restricted to microglia and tanycytes, whereas IL6 receptor is expressed in microglia, ependymocytes, endothelial cells, and astrocytes. Exogenous IL6 reduces diet-induced obesity. In outbred mice, obesity-resistance is accompanied by increased expression of IL6 in the hypothalamus. IL6 induces neurogenesis-related gene expression in the hypothalamus and in neuroprogenitor cells, both from WT as well as from KO mice. CONCLUSION: IL6 induces neurogenesis-related gene expression in the hypothalamus of WT mice. In KO mice, the neurogenic actions of IL6 are preserved; however, the appearance of new fully differentiated proopiomelanocortin (POMC) and neuropeptide Y (NPY) neurons is either delayed or disturbed.

Pro-Inflammatory Markers Negatively Regulate IRS1 in Endometrial Cells and Endometrium from Women with Obesity and PCOS.

A pro-inflammatory environment is characteristic of obesity and polycystic ovary syndrome (PCOS). This environment through cytokines secretion negatively affects insulin action. Endometria from women with both conditions (obesity and PCOS) present high TNF-α level and altered insulin signaling. In addition, these patients present reproductive failures that could be associated to an abnormal endometrial function. Here, TNF-α and IL-6 effects on insulin signaling pathway were evaluated. Serum and endometrial IL-6, phospho-IRS1-S270 (inactive form) and phospho-IRS1-Y612 (active form) levels were evaluated in women with: Normal-Weight, Obesity and Obesity-PCOS. In endometrial cells under hyperandrogenic/hyperinsulinic conditions resembling PCOS, it was evaluated IL-6/TNF-α effects on phospho-IRS1-S270, phospho-IRS1-Y612, phospho-AKT-S473 levels, and S6K and JNK activation (IRS1-inactivating molecules). In obesity groups, diminution of IRS1-active form was observed, being more significantly in Obesity-PCOS; whereas, IRS1-inactive form increased in Obesity-PCOS. Serum and endometrial IL-6 were higher in Obesity-groups compared to Normal-Weight. In endometrial cells, TNF-α increases phospho-IRS1-S270, while IL-6 decreases phospho-IRS1-Y612. Importantly, TNF-α and IL-6 promote S6K and JNK activation; TNF-α increases and IL-6 decreases phospho-AKT-S473 levels. Thus, pro-inflammatory cytokines in endometrium could negatively influence insulin signaling by different mechanisms: TNF-α promotes activation of IRS1-inactivating kinases, whereas, IL-6 decreases IRS1 and AKT activation. Moreover, when obesity and PCOS are present the disruption of insulin signaling is aggravated. These effects could explain endometrial abnormal function and reproductive failures observed in women with obesity and PCOS.

Evaluation of the effects of erythropoietin and interleukin-6 in rats submitted to acute spinal cord injury.

OBJECTIVE: To evaluate the effects of interleukin-6 (IL-6) and erythropoietin (EPO) in experimental acute spinal cord injury (SCI) in rats. METHODS: Using standardized equipment, namely, a New York University (NYU) Impactor, a SCI was produced in 50 Wistar rats using a 10-g weight drop from a 12.5-mm height. The rats were divided into the following 5 groups of 10 animals each: "Group EPO", treated with erythropoietin only; "Group EPO + IL-6", treated with both substances; "Group IL-6", receiving IL-6 administration only; "Group Placebo", receiving a placebo solution; and "Group Sham", submitted to an incomplete procedure (only laminectomy, without SCI). All drugs and the placebo solution were administered intraperitoneally for three weeks. The animals were followed up for 42 days. Functional motor recovery was monitored by the Basso, Beattie, and Bresnahan (BBB) scale on days 2, 7, 14, 21, 28, 35 and 42. Motor-evoked potential tests were performed on the 42nd day. Histological analysis was performed after euthanasia. RESULTS: The group receiving EPO exhibited superior functional motor results on the BBB scale. IL-6 administration alone was not superior to the placebo treatment, and the IL-6 combination with EPO yielded worse results than did EPO alone. CONCLUSIONS: Using EPO after acute SCI in rats yielded benefits in functional recovery. The combination of EPO and IL-6 showed benefits, but with inferior results compared to those of isolated EPO; moreover, isolated use of IL-6 resulted in no benefit.

TERT inhibition leads to reduction of IL-6 expression induced by palmitic acid and interferes with the protective effects of tibolone in an astrocytic cell model.

Although it has been shown that telomerase has neuroprotective effects, mainly as a result of its non-canonical functions in neuronal cells, its role with respect to glial cells remains unknown. There is growing evidence indicating that telomerase plays an important role with respect to inflammation, especially in the regulation of pro-inflammatory cytokine gene expression. The present study aimed to evaluate the role of telomerase in an astrocyte cell model treated with palmitic acid (PA) and tibolone. Cell death, reactive oxygen species production and interleukin-6 expression were evaluated under telomerase inhibition with the BIBR1532 compound in T98G cells treated with tibolone and PA, using fluorometry, flow cytometry, enzyme-linked immunosorbent assays and the quantitative polymerase chain reaction. The results obtained showed that telomerase protein was increased by PA after 36 hours, alone or in combination with tibolone, and that its activity was affected by PA. Telomerase inhibition reduced interleukin-6 expression and it interfered with the protective effects of tibolone on cell death. Moreover, tibolone increased Tyr707 phosphorylation in PA-treated cells. In the present study, we provide novel findings about the regulation of telomerase by PA and tibolone. Telomerase was involved in inflammation by PA and in protective effects of tibolone. Therefore, we conclude that telomerase could play a dual role in these cells.