Targeting liver and adipose tissue in obese mice: Effects of a N-acylethanolamine mixture on insulin resistance and adipocyte reprogramming.

N-acylethanolamines (NAEs) are endogenous lipid-signalling molecules involved in inflammation and energy metabolism. The potential pharmacological effect of NAE association in managing inflammation-based metabolic disorders is unexplored. To date, targeting liver-adipose axis can be considered a therapeutic approach for the treatment of obesity and related dysfunctions. Here, we investigated the metabolic effect of OLALIAMID® (OLA), an olive oil-derived NAE mixture, in limiting liver and adipose tissue (AT) dysfunction of high-fat diet (HFD)-fed mice. OLA reduced body weight and fat mass in obese mice, decreasing insulin resistance (IR), as shown by homeostasis model assessment index, and leptin/adiponectin ratio, a marker of adipocyte dysfunction. OLA improved serum lipid and hepatic profile and the immune/inflammatory pattern of metainflammation. In liver of HFD mice, OLA treatment counteracted glucose and lipid dysmetabolism, restoring insulin signalling (phosphorylation of AKT and AMPK), and reducing mRNAs of key markers of fatty acid accumulation. Furthermore, OLA positively affected AT function deeply altered by HFD by reprogramming of genes involved in thermogenesis of interscapular brown AT (iBAT) and subcutaneous white AT (scWAT), and inducing the beigeing of scWAT. Notably, the NAE mixture reduced inflammation in iBAT and promoted M1-to-M2 macrophage shift in scWAT of obese mice. The tissue and systemic anti-inflammatory effects of OLA and the increased expression of glucose transporter 4 in scWAT contributed to the improvement of gluco-lipid toxicity and insulin sensitivity. In conclusion, we demonstrated that this olive oil-derived NAE mixture is a valid nutritional strategy to counteract IR and obesity acting on liver-AT crosstalk, restoring both hepatic and AT function and metabolism.

Alkalihalobacillus clausii (formerly Bacillus clausii) spores lessen antibiotic-induced intestinal injury and reshape gut microbiota composition in mice.

The antibiotic-induced intestinal injury (AIJ) is associated with diarrhoea and gastrointestinal discomfort. However, the pathological intestinal mechanisms and related side effects associated with antibiotic use/misuse may be counteracted by probiotics. This study aims to evaluate the effect and the protective mechanisms of a probiotic formulation containing Alkalihalobacillus clausii (formerly Bacillus clausii; BC) spores in an experimental model of AIJ. C57/Bl6J mice were orally challenged with a high dose of ceftriaxone for five days along with BC treatment which lasted up to the 15th day. Our results showed the beneficial effect of the probiotic in preserving colonic integrity and limiting tissue inflammation and immune cell infiltration in AIJ mice. BC increased tight junction expression and regulated the unbalanced production of colonic pro- and anti-inflammatory cytokines, converging toward the full resolution of the intestinal damage. These findings were supported by the histological evaluation of the intestinal mucosa, suggesting a potential restoration of mucus production. Notably, BC treatment increased gene transcription of the secretory products responsible for epithelium repair and mucus synthesis and normalized the expression of antimicrobial peptides involved in immune activation. Reconstruction of complex and diverse gut microbiota in antibiotic-induced dysbiosis was recorded upon BC supplementation. Specifically, the expansion of A. clausii, Prevotella rara and Eubacterium ruminatium drove intestinal microbiota rebalance by primarily impacting Bacteroidota members. Taken together, our data indicate that BC administration alleviates AIJ by multiple converging mechanisms leading to restoring gut integrity and homeostasis and reshaping microbiota composition.

Bisphenol A exacerbates anxiety-like behavior and neuroinflammation in prefrontal cortex of adult obese mice.

AIMS: Bisphenol A (BPA) is an endocrine-disrupting chemical inducing several damages such as neurotoxicity, immunotoxicity, and metabolic disorders. Obesity is the main risk factor for the increased occurrence of metabolic alterations as well as mood disorders. Here, we investigated in obese mice the effects of BPA on anxiety-like behavior, associated with neuroinflammation and immune activation. MAIN METHODS: Male C57Bl/6J mice were divided into 4 groups: control group (STD) receiving chow diet and BPA vehicle; STD group treated with BPA (50 µg/kg/die); high-fat diet (HFD) group receiving BPA vehicle; HFD group treated with BPA. BPA treatment started 12 weeks after HFD feeding and lasted 3 weeks. KEY FINDINGS: The open field and elevated plus-maze tests showed in HFD + BPA group the worsening of HFD-induced anxiety-like behavior. The anxiogenic effects of BPA also emerged from hyperactivation of the hypothalamus-pituitary-adrenal gland axis, determined by the increased transcription of Crh and its receptor in the prefrontal cortex (PFC). Furthermore, BPA activated NLRP3 inflammasome and exacerbated the neuroinflammation induced by HFD, increasing IL-1ß, TNF-α and monocyte chemoattractant protein (MCP)-1 in PFC. Furthermore, it induced inflammation and monocyte recruitment in hypothalamus and amygdala. Contextually, BPA significantly amplified the immune activation caused by lipid overload as evidenced by the increased expression of TLR-4 and MCP-1 in the PFC and triggered mastocytosis in the hypothalamus rather than STD mice. SIGNIFICANCE: All these data show that sub-chronic BPA exposure represents an additional risk factor for mood disorders strictly related to obesity, enhancing neuroinflammation and immune activation triggered by HFD feeding.

Amyloid precursor protein, lipofuscin accumulation and expression of autophagy markers in aged bovine brain.

BACKGROUND: Autophagy is a highly regulated process involving the bulk degradation of cytoplasmic macromolecules and organelles in mammalian cells via the lysosomal system. Dysregulation of autophagy is implicated in the pathogenesis of many neurodegenerative diseases and integrity of the autophagosomal - lysosomal network appears to be critical in the progression of aging. Our aim was to survey the expression of autophagy markers and Amyloid precursor protein (APP) in aged bovine brains. For our study, we collected samples from the brain of old (aged 11-20 years) and young (aged 1-5 years) Podolic dairy cows. Formalin-fixed and paraffin embedded sections were stained with routine and special staining techniques. Primary antibodies for APP and autophagy markers such as Beclin-1 and LC3 were used to perform immunofluorescence and Western blot analysis. RESULTS: Histologically, the most consistent morphological finding was the age-related accumulation of intraneuronal lipofuscin. Furthermore, in aged bovine brains, immunofluorescence detected a strongly positive immunoreaction to APP and LC3. Beclin-1 immunoreaction was weak or absent. In young controls, the immunoreaction for Beclin-1 and LC3 was mild while the immunoreaction for APP was absent. Western blot analysis confirmed an increased APP expression and LC3-II/LC3-I ratio and a decreased expression of Beclin-1 in aged cows. CONCLUSIONS: These data suggest that, in aged bovine, autophagy is significantly impaired if compared to young animals and they confirm that intraneuronal APP deposition increases with age.

Palmitoylethanolamide prevents metabolic alterations and restores leptin sensitivity in ovariectomized rats.

It has been suggested a role of fatty acid ethanolamides in control of feeding behavior. Among these, palmitoylethanolamide (PEA) has not been directly implicated in appetite regulation and weight gain. The aim of this study was to investigate the effect of PEA on food intake and body weight and the interaction between PEA and hypothalamic leptin signaling in ovariectomized rats. Ovariectomy produced hyperphagia and increased weight gain, making it an useful model of mild obesity. Ovariectomized rats were treated with PEA (30 mg/kg sc) for 5 weeks. Then, blood was collected, and hypothalamus and adipose tissue were removed for histological, cellular, and molecular measurements. We showed that PEA caused a reduction of food intake, body weight, and fat mass. The mechanisms underlying PEA effects involved an improvement in hypothalamic leptin signaling, through a raise in signal transducer and activator of transcription 3 phosphorylation. We also reported that PEA reduced AMP-activated protein kinase-α phosphorylation and modulated transcription of anorectic and orexigenic neuropeptides in the hypothalamus. Moreover, PEA increased AMP-activated protein kinase-α phosphorylation and carnitine palmitoyltransferase 1 transcription in adipose tissue, suggesting an increase in ATP-producing catabolic pathway. PEA also polarized adipose tissue macrophages to M2 lean phenotype, associated to a reduction of inflammatory cytokines/adipokines. To demonstrate the direct effect of PEA on leptin sensitivity without interference of adiposity loss, we obtained consistent data in PEA-treated sham-operated animals and in vitro in SH-SY5Y neuroblastoma cell line. Therefore, our data provide a rationale for the therapeutic use of PEA in obese postmenopausal woman.

Cross-talk between toll-like receptor 4 (TLR4) and proteinase-activated receptor 2 (PAR(2) ) is involved in vascular function.

BACKGROUND AND PURPOSE: Proteinase-activated receptors (PARs) and toll-like receptors (TLRs) are involved in innate immune responses. The aim of this study was to evaluate the possible cross-talk between PAR(2) and TLR4 in vessels in physiological condition and how it varies following stimulation of TLR4 by using in vivo and ex vivo models. EXPERIMENTAL APPROACH: Thoracic aortas were harvested from both naïve and endotoxaemic rats for in vitro studies. Arterial blood pressure was monitored in anaesthetized rats in vivo. LPS was used as a TLR4 agonist while PAR(2) activating peptide (AP) was used as a PAR(2) agonist. Aortas harvested from TLR4(-/-) mice were also used to characterize the PAR(2) response. KEY RESULTS: PAR(2) , but not TLR4, expression was enhanced in aortas of endotoxaemic rats. PAR(2) AP-induced vasorelaxation was increased in aortic rings of LPS-treated rats. TLR4 inhibitors, curcumine and resveratrol, reduced PAR(2) AP-induced vasorelaxation and PAR(2) AP-induced hypotension in both naïve and endotoxaemic rats. Finally, in aortic rings from TLR4(-/-) mice, the expression of PAR(2) was reduced and the PAR(2) AP-induced vasodilatation impaired compared with those from wild-type mice and both resveratrol and curcumine were ineffective. CONCLUSIONS AND IMPLICATIONS: Cross-talk between PAR(2) and TLR4 contributes to vascular homeostasis.

Central administration of oxytocin reduces hyperalgesia in mice: implication for cannabinoid and opioid systems.

The neuropeptide oxytocin (OXT) contributes to the regulation of diverse cognitive and physiological functions including nociception. Indeed, OXT has been reported to be analgesic when administered directly into the brain, the spinal cord, or systemically. Although many authors have reported the analgesic effects of OXT, its mechanism has not been well elucidated. Recently, it has been also hypothesize that OXT, increasing intracellular concentration of calcium, could regulate the production of mediators, like endocannabinoids (eCB). It has been well documented that eCB are able to suppress pain pathways. The present study investigates the effect of OXT in paw carrageenan-induced pain. Intracerebroventricular (icv) administration of OXT, but neither intraperitoneal nor intraplantar route, induces an antihyperalgesic effect increasing paw withdrawal latency to mechanical or thermal stimuli. Our results clearly demonstrate that 3 and 6h following carrageenan challenge, central administration of OXT (30 ng/mouse) shows a significant antihyperalgesic activity. Moreover, for the first time, we demonstrate that CB1 receptor plays a key role in the antihyperalgesic effect of OXT. In fact our results show CB1 antagonist, but not the specific CB2 antagonist reduce OXT-induced antihyperalgesic effect. In addition, our data show that central OXT administration is able to reduce carrageenan-induced hyperalgesia but does not modify carrageenan-induced paw edema. Finally, using opioid antagonists we confirm an important role of opioid receptors. In conclusion, our experiments suggest that central administration of OXT reduces hyperalgesia induced by intraplantar injection of carrageenan, and this effect may work via cannabinoid and opioid systems.

Effects of non-dioxin-like polychlorinated biphenyl congeners (PCB 101, PCB 153 and PCB 180) alone or mixed on J774A.1 macrophage cell line: modification of apoptotic pathway.

Non-dioxin-like polychlorinated biphenyls (PCBs) are stable and lipophilic chemicals that persist in the environment and tend to bioaccumulate in the food chains. In the present study, we have investigated the effect of PCBs 101, 153, and 180 on macrophage J774A.1 by assessing cell viability and apoptotic cell death. We have combined morphological techniques and biochemical ones to establish the relevance of apoptosis in macrophage cell death induced by PCBs, alone or in combination. Treatment with the examined PCBs caused the loss of cell viability and accelerated apoptosis in a concentration-dependent manner. Moreover, a synergistic effect on cell death and apoptosis was evidenced for all PCBs at concentrations which were inactive alone. The apoptosis induced by PCBs involved the increase of caspase-3 activity. Also, Bcl-2 and Bax proteins were assessed to elucidate the apoptosis machinery induced in macrophage cultures by PCBs. Our results indicate that the increase in PCB-induced apoptosis correlates with a reduction in the expression of antiapoptotic Bcl-2 and an increase in the expression of proapoptotic Bax. Interestingly, concentrations of PCBs inactive by themselves induce apoptosis when PCBs are combined. In conclusion, our findings suggest that, although less toxic than dioxin like congeners, the examined non-dioxin-like PCBs are equally dangerous as immunotoxic pollutants, also considering their presence as mixtures at higher levels than dioxin-like PCBs in biotic and abiotic matrices.

Evaluation of placental protein modifications in normotensive and spontaneously hypertensive rats.

Hypertension in pregnancy is often associated to placental deficiency. Therefore several physiopathological modifications occur to sustain fetal well-being through protective mechanisms. Here, we used spontaneously hypertensive rat (SHR) and normotensive Wistar-Kyoto (WKY) counterpart to evaluate in late gestation (d 20) modification of placental proteins involved in adaptation to hypertension. Placenta from WKY and SHR was excised for the evaluation of protein changes by Western blot analysis and zymography. In particular, we showed in SHR placentas an increase in angiotensin receptor type 1 and a decrease in angiotensin converting enzyme. Conversely, inducible nitric oxide synthase expression was increased, while constitutive endothelial nitric oxide synthase was similar in both groups. Placentas from SHR showed a reduced protein expression in both peroxisome proliferators-activated receptors-alpha and -gamma. Pro-metalloproteinase-9 activity was not significantly modified, whereas both pro-metalloproteinase-2 and its active form present a higher activity in SHR placentas. Moreover, at the end of pregnancy, cyclooxygenase-2 expression decreased in SHR placentas. These data may provide new insights into the placental adaptive mechanisms that take place during pregnancy in SHR.

Th1-Th2 response in hyperprolactinemic mice infected with Salmonella enterica serovar Typhimurium.

Prolactin (PRL) is a pituitary hormone and a cytokine known to regulate several physiological functions. It plays a role in modulating the immune system of rodents and humans. A hormonal protection against listeria and salmonella infections has been previously ascribed to effects of PRL on immunocompetent cells. Here, the role of PRL in the Th1-Th2 response was evaluated based on the pattern of cytokines release by splenocytes from hyperprolactinemic mice infected with Salmonella enterica serovar Typhimurium. Hyperprolactinemia by pituitary graft reduced the number of bacteria in spleens of in vivo infected mice. Modulation of Th1 (IFN-gamma, IL-12) and Th2 (IL-4, IL-10) cytokine production by splenic cells was found. Our results indicate that PRL can up-regulate IFN-c and IL-12 secretion in response to salmonella infection, confirming its in vivo immunostimulatory effect and suggesting hormonal participation in the genesis and sustenance of the Th1 response.

The effect of age and sex on the expression of prolactin binding activity in the chicken bursa of Fabricius.

The binding of 125I-labeled prolactin (PRL) to membranes from the bursa of Fabricius of male and female chicks of different ages (15-30-45 and 60 days) was studied. In male chicks the binding was very low in 15 day-old animals and slightly increased in more aged animals. In female chicks the binding was more evident in young animals and decreased in 60 day-old animals. The binding showed a hormonal specificity and Scatchard analysis of the binding revealed the presence of binding sites with low capacity and high affinity. The presence of PRL receptors in the bursa of the chick, a structure that confers immunological competence to birds, gives further support to the involvement of the hormone in the immune processes.