The aim of this study was to investigate whether treatment with tributyrin (Tb; a butyrate prodrug) results in protection against diet-induced obesity and associated insulin resistance. C57BL/6 male ...mice fed a standard chow or high-fat diet were treated with Tb (2 g/kg body wt, 10 wk) and evaluated for glucose homeostasis, plasma lipid profile, and inflammatory status. Tb protected mice against obesity and obesity-associated insulin resistance and dyslipidemia without food consumption being affected. Tb attenuated the production of TNFα and IL-1β by peritoneal macrophages and their expression in adipose tissue. Furthermore, in the adipose tissue, Tb reduced the expression of MCP-1 and infiltration by leukocytes and restored the production of adiponectin. These effects were associated with a partial reversion of hepatic steatosis, reduction in liver and skeletal muscle content of phosphorylated JNK, and an improvement in muscle insulin-stimulated glucose uptake and Akt signaling. Although part of the beneficial effects of Tb are likely to be secondary to the reduction in body weight, we also found direct protective actions of butyrate reducing TNFα production after LPS injection and in vitro by LPS- or palmitic acid-stimulated macrophages and attenuating lipolysis in vitro and in vivo. The results, reported herein, suggest that Tb may be useful for the treatment and prevention of obesity-related metabolic disorders.
Omega-3 polyunsaturated fatty acids (n-3 PUFAs) have been reported to improve insulin sensitivity and glucose homeostasis in animal models of insulin resistance, but the involved mechanisms still ...remain unresolved. In this study, we evaluated the effects of fish oil (FO), a source of n-3 PUFAs, on obesity, insulin resistance and muscle mitochondrial function in mice fed a high-fat diet (HFD). C57Bl/6 male mice, 8 weeks old, were divided into four groups: control diet (C), high-fat diet (H), C+FO (CFO) and H+FO (HFO). FO was administered by oral gavage (2 g/kg b.w.), three times a week, starting 4 weeks before diet administration until the end of the experimental protocol. HFD-induced obesity and insulin resistance associated with impaired skeletal muscle mitochondrial function, as indicated by decreased oxygen consumption, tricarboxylic acid cycle intermediate (TCAi) contents (citrate, α-ketoglutarate, malate and oxaloacetate), oxidative phosphorylation protein content and mitochondrial biogenesis. These effects were associated with elevated reactive oxygen species production, decreased PGC1-a transcription and reduced Akt phosphorylation. The changes induced by the HFD were partially attenuated by FO, which decreased obesity and insulin resistance and increased mitochondrial function. In the H group, FO supplementation also improved oxygen consumption; increased TCAi content, and Akt and AMPK phosphorylation; and up-regulated mRNA expression of Gpat1, Pepck, catalase and mitochondrial proteins (Pgc1α, Pparα, Cpt1 and Ucp3). These results suggest that dietary FO attenuates the deleterious effects of the HFD (obesity and insulin resistance) by improving skeletal muscle mitochondrial function.
Propolis extracts are widely used in traditional folk medicine and exhibit several properties such as antitumor, anti-inflammatory, and antimicrobial. However, these products have not been ...investigated in combination with medicines used in clinical practice.
This study aimed to evaluate the chemical composition of propolis extracts from Apis mellifera scutellata and different Meliponini species and characterize their cytotoxicity against tumor cells, antibacterial effects, and interference with the actions of doxorubicin and gentamicin.
Chromatographic and spectrometric analyses were performed using ultra-high-performance liquid chromatography (UPLC)-tandem mass spectrometry (MS/MS). Propolis extracts were evaluated for cytotoxicity and synergism using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the antimicrobial activity was examined using the broth microdilution technique and synergism was investigated using checkerboard and time-kill assays.
The chemical characterization revealed the presence of 63 compounds, and the extracts showed selective cytotoxicity against tumor cell lines. Propolis extracts of mandaçaia and mirim exerted selective synergistic cytotoxicity in combination with doxorubicin. Except for the tubuna extract, all evaluated extracts exhibited antibacterial effects on gram-positive strains. Mandaçaia and mirim extracts exerted a synergistic effect with gentamicin; however, only mandaçaia extract exerted a selective effect.
Propolis could be a source of antineoplastics and antibiotics. These natural products may reduce the occurrence of doxorubicin and gentamicin related adverse effects, resistance, or both.
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•63 compounds were identified in propolis extracts.•Propolis extracts exert selective synergistic cytotoxicity with doxorubicin.•Propolis extracts have antibacterial action.•Propolis extract exerts selective synergistic effect with gentamicin.
Key points
Fish oil (FO), rich in omega‐3 polyunsaturated fatty acids, has beneficial effects on changes induced by obesity and partially prevents associated comorbidities.
The effects of FO on ...adipocytes from different adipose tissue depots in high‐fat (HF) diet induced obese mice have not been uninvestigated.
This is the first study to examine the effects of FO on changes in metabolism and adipokine production in adipocytes from s.c. (inguinal; ING) or visceral (retroperitoneal; RP) white adipose depots in a HF diet‐induced obese mice.
Unlike most studies performed previously, FO supplementation was initiated 4 weeks before the induction of obesity.
HF diet caused marked changes in ING (glucose uptake and secretion of adiponectin, tumour necrosis factor‐α and interleukin‐6 in ING) and RP (lipolysis, de novo lipogenesis and secretion of pro‐inflammatory cytokines) adipose depots.
Previous and concomitant FO administration prevented the changes in ING and RP adipocytes induced by the HF diet.
In the present study, we investigated the effect of fish oil (FO) on metabolism and adipokine production by adipocytes from s.c. (inguinal; ING) and visceral (retroperitoneal; RP) white adipose depots in high‐fat (HF) diet‐induced obese mice. Mice were divided into CO (control diet), CO+FO, HF and HF+FO groups. The HF group presented higher body weight, glucose intolerance, insulin resistance, higher plasma total and low‐density lipoprotein cholesterol levels, and greater weights of ING and RP adipose depots accompanied by hypertrophy of the adipocytes. FO exerted anti‐obesogenic effects associated with beneficial effects on dyslipidaemia and insulin resistance in mice fed a HF diet (HF+FO group). HF raised RP adipocyte lipolysis and the production of pro‐inflammatory cytokines and reduced de novo synthesis of fatty acids, whereas, in ING adipocytes, it decreased glucose uptake and adiponectin secretion but did not change lipolysis. Therefore, the adipose depots play different roles in HF diet‐induced insulin resistance according to their location in the body. Concerning cytokine secretion, adipocytes per se in addition to white adopise tissue infiltrated leukocytes have to be considered in the aetiology of the comorbidities associated with obesity. Evidence is presented showing that previous and concomitant administration of FO can prevent changes in metabolism and the secretion of hormones and cytokines in ING and RP adipocytes induced by HF.
Key points
Fish oil (FO), rich in omega‐3 polyunsaturated fatty acids, has beneficial effects on changes induced by obesity and partially prevents associated comorbidities.
The effects of FO on adipocytes from different adipose tissue depots in high‐fat (HF) diet induced obese mice have not been uninvestigated.
This is the first study to examine the effects of FO on changes in metabolism and adipokine production in adipocytes from s.c. (inguinal; ING) or visceral (retroperitoneal; RP) white adipose depots in a HF diet‐induced obese mice.
Unlike most studies performed previously, FO supplementation was initiated 4 weeks before the induction of obesity.
HF diet caused marked changes in ING (glucose uptake and secretion of adiponectin, tumour necrosis factor‐α and interleukin‐6 in ING) and RP (lipolysis, de novo lipogenesis and secretion of pro‐inflammatory cytokines) adipose depots.
Previous and concomitant FO administration prevented the changes in ING and RP adipocytes induced by the HF diet.
We have recently demonstrated that palmitoleic acid (16:1n7) increases lipolysis, glucose uptake and glucose utilization for energy production in white adipose cells. In the present study, we tested ...the hypothesis that palmitoleic acid modulates bioenergetic activity in white adipocytes.
For this, 3 T3-L1 pre-adipocytes were differentiated into mature adipocytes in the presence (or absence) of palmitic (16:0) or palmitoleic (16:1n7) acid at 100 or 200 μM. The following parameters were evaluated: lipolysis, lipogenesis, fatty acid (FA) oxidation, ATP content, oxygen consumption, mitochondrial mass, citrate synthase activity and protein content of mitochondrial oxidative phosphorylation (OXPHOS) complexes.
Treatment with 16:1n7 during 9 days raised basal and isoproterenol-stimulated lipolysis, FA incorporation into triacylglycerol (TAG), FA oxidation, oxygen consumption, protein expression of subunits representing OXPHOS complex II, III, and V and intracellular ATP content. These effects were not observed in adipocytes treated with 16:0.
Palmitoleic acid, by concerted action on lipolysis, FA esterification, mitochondrial FA oxidation, oxygen consumption and ATP content, does enhance white adipocyte energy expenditure and may act as local hormone.
Asthma is a chronic inflammatory disease that affects more females than males after puberty, and its symptoms and severity in women change during menstruation and menopause. Recently, evidence has ...demonstrated that interactions among the microbiota, female sex hormones, and immunity are associated with the development of autoimmune diseases. However, no studies have investigated if therapeutic gut microbiota modulation strategies could affect asthma exacerbation during menstruation and menopause. Here we aimed to examine the preventive effects of a probiotic,
Bifidobacterium longum
5
1A
, on airway inflammation exacerbation in allergic ovariectomized mice. We first evaluated the gut microbiota composition and diversity in mice 10 days after ovariectomy. Next, we examined whether re-exposure of ovariectomized allergic mice to antigen (ovalbumin) would lead to exacerbation of lung inflammation. Finally, we evaluated the preventive and treatment effect of
B. longum
5
1A
on lung inflammation and airway hyperresponsiveness. Our results showed that whereas ovariectomy caused no alterations in the gut microbiota composition and diversity in this animal model, 10 days after ovariectomy, preventive use administration of
B. longum
5
1A
, rather than its use after surgery was capable of attenuate the exacerbated lung inflammation and hyperresponsiveness in ovariectomized allergic mice. This prophylactic effect of
B. longum
5
1A
involves acetate production, which led to increased fecal acetate levels and, consequently, increased Treg cells in ovariectomized allergic mice.
The phenotypes of allergic airway diseases are influenced by the interplay between host genetics and the gut microbiota, which may be modulated by probiotics. We investigated the probiotic effects on ...allergic inflammation in A/J and C57BL/6 mice. C57BL/6 mice had increased gut microbiota diversity compared to A/J mice at baseline. Acetate producer probiotics differentially modulated and altered the genus abundance of specific bacteria, such as Akkermansia and Allistipes, in mouse strains. We induced airway inflammation followed by probiotic treatment and found that only A/J mice exhibited decreased inflammation, and the beneficial effects of probiotics in A/J mice were partially due to acetate production. To understand the relevance of microbial composition colonization in the development of allergic diseases, we implanted female C57BL/6 mice with A/J embryos to naturally modulate the microbial composition of A/J mice, which increased gut microbiota diversity and reduced eosinophilic inflammation in A/J. These data demonstrate the central importance of microbiota to allergic phenotype severity. Video Abstract.
Mitochondrial glutaminase (GA) plays an essential role in cancer cell metabolism, contributing to biosynthesis, bioenergetics, and redox balance. Humans contain several GA isozymes encoded by the
GLS
...and
GLS2
genes, but the specific roles of each in cancer metabolism are still unclear. In this study, glioma SFxL and LN229 cells with silenced isoenzyme glutaminase KGA (encoded by
GLS
) showed lower survival ratios and a reduced GSH-dependent antioxidant capacity. These
GLS
-silenced cells also demonstrated induction of apoptosis indicated by enhanced annexin V binding capacity and caspase 3 activity.
GLS
silencing was associated with decreased mitochondrial membrane potential (ΔΨm) (JC-1 dye test), indicating that apoptosis was mediated by mitochondrial dysfunction. Similar observations were made in T98 glioma cells overexpressing glutaminase isoenzyme GAB, encoded by
GLS2
, though some characteristics (GSH/GSSG ratio) were different in the differently treated cell lines. Thus, control of GA isoenzyme expression may prove to be a key tool to alter both metabolic and oxidative stress in cancer therapy. Interestingly, reactive oxygen species (ROS) generation by treatment with oxidizing agents: arsenic trioxide or hydrogen peroxide, synergizes with either KGA silencing or GAB overexpression to suppress malignant properties of glioma cells, including the reduction of cellular motility. Of note, negative modulation of GLS isoforms or GAB overexpression evoked lower c-myc and bcl-2 expression, as well as higher pro-apoptotic bid expression. Combination of modulation of GA expression and treatment with oxidizing agents may become a therapeutic strategy for intractable cancers and provides a multi-angle evaluation system for anti-glioma pre-clinical investigations.
Key message
Silencing
GLS
or overexpressing
GLS2
induces growth inhibition in glioma cell lines.
Inhibition is synergistically enhanced after arsenic trioxide (ATO) or H
2
O
2
treatment.
Glutatione levels decrease in
GLS
-silenced cells but augment if
GLS2
is overexpressed.
ROS synergistically inhibit cell migration by
GLS
silencing or
GLS2
overexpression.
c-myc, bid, and bcl-2 mediate apoptosis resulting from
GLS
silencing or
GLS2
overexpression.
Cancer is an inflammatory disease because carcinogenesis and tumor progression depend on intrinsic and extrinsic inflammatory pathways. Although species of the genus Aspidosperma are widely used to ...treat tumors, and there is ethnopharmacological evidence for traditional use of the species A. subincanum as an anti-inflammatory agent, its antineoplastic potential is unknown.
To evaluate toxic effects of the indole alkaloid–rich fraction (IAF) of A. subincanum on the MCF7 cell line and identify some of the anti-inflammatory mechanisms involved.
Chromatographic analyses were performed by ultra-high-performance liquid chromatography with electrospray ionization mass spectrometry, and cytotoxic and antiproliferative effects of IAF were verified by MTT and clonogenic assays. Cell cycle alterations were analyzed by measuring DNA content, while propidium iodide and acridine orange staining was performed to determine the type of induced cell death. The expression of apoptosis markers and proteins involved in cell proliferation and survival pathways was analyzed by immunoblotting, RT-qPCR, and ELISAs. Interference with redox status was investigated using a DCFH-DA probe and by measuring catalase activity.
Chromatographic analyses showed that IAF is a complex mixture containing indole alkaloids. IAF selectively exerted toxic and antiproliferative effects, elevating the Bax/Bcl-xL ratio and inducing apoptosis in MCF7 cells. IAF decreased intracellular reactive oxygen species levels and increased catalase activity, while reducing the IL-8 level and suppressing COX-2 expression.
IAF induces apoptosis in MCF7 cells by suppressing COX-2 expression while reducing IL-8 levels and intracellular content of reactive oxygen species.
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•Four indolic alkaloids were proposed in IAF.•IAF exerts cytotoxic and antiproliferative effects in MCF7 cells.•IAF induces apoptosis in MCF7 cells.•IAF's cytotoxicity and antiproliferative action involves modulation of redox status.•The effects of IAF in MCF7 cells are related to modulation of inflammatory pathways.
Abstract Objective Protein malnutrition (PM) often is associated with changes in bone marrow (BM) microenvironment leading to an impaired hematopoiesis; however, the mechanism involved is poorly ...understood. The aim of this study was to compare the cell cycle progression of hematopoietic stem cells (HSC) and hematopoietic progenitor cells (HPC) and evaluate the cell cycle signaling in malnourished mice to assess the mechanism of cell cycle arrest. Methods C57Bl/6J mice were randomly assigned in control and malnourished groups receiving normoproteic and hypoproteic diets (12% and 2% protein, respectively) over a 5-wk period. Nutritional and hematologic parameters were assessed and BM immunophenotypic analysis was performed. Cell cycle of HPC (Lin– ) and HSC (Lin– Sca-1+ c-Kit+ ) were evaluated after 6 h of in vivo 5-bromo-2'-deoxyuridine (BrDU) incorporation. Cell cycle regulatory protein expression of HPC was assessed by Western blot. Results Malnourished mice showed lower levels of serum protein, albumin, glucose, insulin-like growth factor-1, insulin, and higher levels of serum corticosterone. PM also caused a reduction of BM myeloid compartment resulting in anemia and leukopenia. After 6 h of BrDU incorporation, malnourished mice showed G0-G1 arrest of HPC without changes of HSC proliferation kinetics. HPC of malnourished mice showed reduced expression of proteins that induce cell cycle (cyclin D1, cyclin E, pRb, PCNA, Cdc25a, Cdk2, and Cdk4) and increased expression of inhibitory proteins (p21 and p27) with no significant difference in p53 expression. Conclusion PM suppressed cell cycle progression mainly of HPC. This occurred via cyclin D1 down-regulation and p21/p27 overexpression attesting that BM microenvironment commitment observed in PM is affecting cell interactions compromising cell proliferation.
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