Fluoxetine ameliorates high-fat diet-induced metabolic abnormalities partially via reduced adipose triglyceride lipase-mediated adipocyte lipolysis

Semaglutide Attenuates Anxious and Depressive-Like Behaviors and Reverses the Cognitive Impairment in a Type 2 Diabetes Mellitus Mouse Model Via the Microbiota-Gut-Brain Axis

Newly conducted research suggests that metabolic disorders, like diabetes and obesity, play a significant role as risk factors for psychiatric disorders. This connection presents a potential avenue for creating novel antidepressant medications by repurposing drugs originally developed to address antidiabetic conditions. Earlier investigations have shown that GLP-1 (Glucagon-like Peptide-1) analogs exhibit neuroprotective qualities in various models of neurological diseases, encompassing conditions such as Alzheimer's disease, Parkinson's disease, and stroke. Moreover, GLP-1 analogs have demonstrated the capability to enhance neurogenesis, a process recognized for its significance in memory formation and the cognitive and emotional aspects of information processing. Nonetheless, whether semaglutide holds efficacy as both an antidepressant and anxiolytic agent remains uncertain. To address this, our study focused on a mouse model of depression linked to type 2 diabetes induced by a High Fat Diet (HFD). In this model, we administered semaglutide (0.05 mg/Kg intraperitoneally) on a weekly basis to evaluate its potential as a therapeutic option for depression and anxiety. Diabetic mice had higher blood glucose, lipidic profile, and insulin resistance. Moreover, mice fed HFD showed higher serum interleukin (IL)-1β and lipopolysaccharide (LPS) associated with impaired humor and cognition. The analysis of behavioral responses revealed that the administration of semaglutide effectively mitigated depressive- and anxiety-like behaviors, concurrently demonstrating an enhancement in cognitive function. Additionally, semaglutide treatment protected synaptic plasticity and reversed the hippocampal neuroinflammation induced by HFD fed, improving activation of the insulin pathway, demonstrating the protective effects of semaglutide. We also found that semaglutide treatment decreased astrogliosis and microgliosis in the dentate gyrus region of the hippocampus. In addition, semaglutide prevented the DM2-induced impairments of pro-opiomelanocortin (POMC), and G-protein-coupled receptor 43 (GPR43) and simultaneously increased the NeuN + and Glucagon-like Peptide-1 receptor (GLP-1R+) neurons in the hippocampus. Our data also showed that semaglutide increased the serotonin (5-HT) and serotonin transporter (5-HTT) and glutamatergic receptors in the hippocampus. At last, semaglutide changed the gut microbiota profile (increasing Bacterioidetes, Bacteroides acidifaciens, and Blautia coccoides) and decreased leaky gut, improving the gut-brain axis. Taken together, semaglutide has the potential to act as a therapeutic tool for depression and anxiety.

ADAR2 deficiency ameliorates non-alcoholic fatty liver disease and muscle atrophy through modulating serum amyloid A1

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide. Sarcopenia is a syndrome characterized by progressive and generalized loss of skeletal muscle mass and strength, which is commonly associated with NAFLD. Adenosine-to-inosine editing, catalysed by adenosine deaminase acting on RNA (ADAR), is an important post-transcriptional modification of genome-encoded RNA transcripts. Three ADAR gene family members, including ADAR1, ADAR2 and ADAR3, have been identified. However, the functional role of ADAR2 in obesity-associated NAFLD and sarcopenia remains unclear.

METHODS

ADAR2+/+/GluR-BR/R mice (wild type [WT]) and ADAR2-/-/GluR-BR/R mice (ADAR2 knockout [KO]) were subjected to feeding with standard chow or high-fat diet (HFD) for 20 weeks at the age of 5 weeks. The metabolic parameters, hepatic lipid droplet, grip strength test, rotarod test, muscle weight, fibre cross-sectional area (CSA), fibre types and protein associated with protein degradation were examined. Systemic and local tissues serum amyloid A1 (SAA1) were measured. The effects of SAA1 on C2C12 myotube atrophy were investigated.

RESULTS

ADAR2 KO mice fed with HFD exhibited lower body weight (-7.7%, P < 0.05), lower liver tissue weight (-20%, P < 0.05), reduced liver lipid droplets in concert with a decrease in hepatic triglyceride content (-24%, P < 0.001) and liver injury (P < 0.01). ADAR2 KO mice displayed protection against HFD-induced glucose intolerance, insulin resistance and dyslipidaemia. Skeletal muscle mass (P < 0.01), muscle strength (P < 0.05), muscle endurance (P < 0.001) and fibre size (CSA; P < 0.0001) were improved in ADAR2 KO mice fed with HFD compared with WT mice fed with HFD. Muscle atrophy-associated transcripts, such as forkhead box protein O1, muscle atrophy F-box/atrogin-1 and muscle RING finger 1/tripartite motif-containing 63, were decreased in ADAR2 KO mice fed with HFD compared with WT mice fed with HFD. ADAR2 deficiency attenuates HFD-induced local liver and skeletal muscle tissue inflammation. ADAR2 deficiency abolished HFD-induced systemic (P < 0.01), hepatic (P < 0.0001) and muscular (P < 0.001) SAA1 levels. C2C12 myotubes treated with recombinant SAA1 displayed a decrease in myotube length (-37%, P < 0.001), diameter (-20%, P < 0.01), number (-39%, P < 0.001) and fusion index (-46%, P < 0.01). Myogenic markers (myosin heavy chain and myogenin) were decreased in SAA1-treated myoblast C2C12 cells.

CONCLUSIONS

These results provide novel evidence that ADAR2 deficiency may be important in obesity-associated sarcopenia and NAFLD. Increased SAA1 might be involved as a regulatory factor in developing sarcopenia in NAFLD.

Deficiency of ADAR2 ameliorates metabolic-associated fatty liver disease via AMPK signaling pathways in obese mice

Non-alcoholic fatty liver disease (NAFLD) is a chronic disease caused by hepatic steatosis. Adenosine deaminases acting on RNA (ADARs) catalyze adenosine to inosine RNA editing. However, the functional role of ADAR2 in NAFLD is unclear. ADAR2+/+/GluR-BR/R mice (wild type, WT) and ADAR2-/-/GluR-BR/R mice (ADAR2 KO) mice are fed with standard chow or high-fat diet (HFD) for 12 weeks. ADAR2 KO mice exhibit protection against HFD-induced glucose intolerance, insulin resistance, and dyslipidemia. Moreover, ADAR2 KO mice display reduced liver lipid droplets in concert with decreased hepatic TG content, improved hepatic insulin signaling, better pyruvate tolerance, and increased glycogen synthesis. Mechanistically, ADAR2 KO effectively mitigates excessive lipid production via AMPK/Sirt1 pathway. ADAR2 KO inhibits hepatic gluconeogenesis via the AMPK/CREB pathway and promotes glycogen synthesis by activating the AMPK/GSK3β pathway. These results provide evidence that ADAR2 KO protects against NAFLD progression through the activation of AMPK signaling pathways.

Neurological and metabolic related pathophysiologies and treatment of comorbid diabetes with depression

BACKGROUND

The comorbidity between diabetes mellitus and depression was revealed, and diabetes mellitus increased the prevalence of depressive disorder, which ranked 13th in the leading causes of disability-adjusted life-years. Insulin resistance, which is common in diabetes mellitus, has increased the risk of depressive symptoms in both humans and animals. However, the mechanisms behind the comorbidity are multi-factorial and complicated. There is still no causal chain to explain the comorbidity exactly. Moreover, Selective serotonin reuptake inhibitors, insulin and metformin, which are recommended for treating diabetes mellitus-induced depression, were found to be a risk factor in some complications of diabetes.

AIMS

Given these problems, many researchers made remarkable efforts to analyze diabetes complicating depression from different aspects, including insulin resistance, stress and Hypothalamic-Pituitary-Adrenal axis, neurological system, oxidative stress, and inflammation. Drug therapy, such as Hydrogen Sulfide, Cannabidiol, Ascorbic Acid and Hesperidin, are conducive to alleviating diabetes mellitus and depression. Here, we reviewed the exact pathophysiology underlying the comorbidity between depressive disorder and diabetes mellitus and drug therapy.

METHODS

The review refers to the available literature in PubMed and Web of Science, searching critical terms related to diabetes mellitus, depression and drug therapy.

RESULTS

In this review, we found that brain structure and function, neurogenesis, brain-derived neurotrophic factor and glucose and lipid metabolism were involved in the pathophysiology of the comorbidity. Obesity might lead to diabetes mellitus and depression through reduced adiponectin and increased leptin and resistin. In addition, drug therapy displayed in this review could expand the region of potential therapy.

CONCLUSIONS

The review summarizes the mechanisms underlying the comorbidity. It also overviews drug therapy with anti-diabetic and anti-depressant effects.

Glucose intolerance induces anxiety-like behaviors independent of obesity and insulin resistance in a novel model of nutritional metabolic stress

OBJECTIVES

Type 2 diabetes (T2D) is a metabolic disease of major public health concern. It impacts peripheral tissues and the central nervous system, leading to systemic dysmetabolism and neurocognitive impairments, including memory deficits, anxiety, and depression. The metabolic determinants of these neurocognitive impairments remain unidentified. Here, we sought to address this question by developing a proprietary (P-) high-fat diet (HFD), in which glucose intolerance precedes weight gain and insulin resistance.

METHODS

The P-HFD model was nutritionally characterized, and tested in vivo in mice that underwent behavioral and metabolic testing. The diet was benchmarked against reference models. .

RESULTS

P-HFD has 42% kcal from fat, high monounsaturated/polyunsaturated fatty acid ratio, and 10% (w/v) sucrose in drinking water. When administered, from the early stages of glucose intolerance alone, animals exhibit anxiety-like behavior, without depression nor recognition memory deficits. Long-term P-HFD feeding leads to weight gain, brain glucose hypometabolism as well as impaired recognition memory. Using an established genetic model of T2D (db/db) and of diet-induced obesity (60% kcal from fat) we show that additional insulin resistance and obesity are associated with depressive-like behaviors and recognition memory deficits.

DISCUSSION

Our findings demonstrate that glucose intolerance alone can elicit anxiety-like behavior. Through this study, we also provide a novel nutritional model (P-HFD) to characterize the discrete effects of glucose intolerance on cognition, behavior, and the physiology of metabolic disease.

Fluoxetine promotes immunometabolic defenses to mediate host-pathogen cooperation during sepsis

Selective serotonin reuptake inhibitors (SSRIs) are some of the most prescribed drugs in the world. While they are used for their ability to increase serotonergic signaling in the brain, SSRIs are also known to have a broad range of effects beyond the brain, including immune and metabolic effects. Recent studies have demonstrated that SSRIs are protective in animal models and humans against several infections, including sepsis and COVID-19, however the mechanisms underlying this protection are largely unknown. Here we mechanistically link two previously described effects of the SSRI fluoxetine in mediating protection against sepsis. We show that fluoxetine-mediated protection is independent of peripheral serotonin, and instead increases levels of circulating IL-10. IL-10 is necessary for protection from sepsis-induced hypertriglyceridemia and cardiac triglyceride accumulation, allowing for metabolic reprogramming of the heart. Our work reveals a beneficial "off-target" effect of fluoxetine, and reveals a protective immunometabolic defense mechanism with therapeutic potential.

Acute and long-lasting effects of adolescent fluoxetine exposure on feeding behavior in Sprague-Dawley rats

The antidepressant medication fluoxetine (FLX) is frequently prescribed for the management of mood-related illnesses in the adolescent population-yet its long-term neurobehavioral consequences are not understood. To investigate how juvenile FLX exposure influences feeding behavior in adulthood, we conducted two experiments. In Experiment 1, adolescent male and female Sprague-Dawley rats were administered with 20 mg/kg/day FLX (postnatal day [PND] 35-49) and exposed to a binge access paradigm in adulthood (PND72+) to evaluate potential alterations for sweetened-fat preference. No long-term FLX-induced differences in preference for sweetened fat versus chow, nor total caloric intake, were noted; however, females displayed higher preference for sweetened fat compared to males. In Experiment 2, PND35 male rats received FLX (PND35-49) and were exposed to chronic variable stress (CVS) in adulthood (PND74-88). During treatment, FLX decreased body weight and intake (meal size), but not total meal number. Also, no differences in meal pattern parameters were observed after FLX completion. Likewise, no differences in meal pattern parameters to a palatable diet (45% fat, 17% sucrose) presented from PND74 to PND88, even after CVS, were observed. Our findings indicate that juvenile FLX reduces body weight gain acutely via reduced meal size intake; however, no long-term changes in ad libitum feeding behavior or binge access to a palatable stimulus are evident.

Oral fluoxetine treatment changes serotonergic sympatho-regulation in experimental type 1 diabetes

AIMS

This study investigated whether fluoxetine treatment changes the 5-HT regulation on vascular sympathetic neurotransmission in type 1 diabetes.

MAIN METHODS

Four-week diabetes was obtained by a single alloxan s.c. administration in male Wistar rats, administering fluoxetine for 14 days (10 mg/kg/day; p.o.). Systolic blood pressure, heart rate, glycaemia, body weight (BW) evolution, creatinine, and blood urea nitrogen (BUN) were monitored. Afterward, rats were pithed to perform the vascular sympathetic stimulation. 5-HT_1A/1D/2A receptors expression was analysed by Western blot in thoracic aorta. Both i.v. norepinephrine and the electrical stimulation of the spinal sympathetic drive evoked vasoconstrictor responses.

KEY FINDINGS

Fluoxetine treatment significantly reduced the BW gain, hyperglycaemia, creatinine, and BUN in diabetic rats. The electrical-produced vasopressor responses were greater in untreated than in fluoxetine-treated diabetic rats. 5-HT decreased the sympathetic-produced vasopressor responses. While 5-CT, 8-OH-DPAT and L-694,247 (5-HT_1/7, 5-HT_1A and 5-HT_1D agonists, respectively) reproduced 5-HT-evoked inhibition, the 5-HT₂ activation by α-methyl-5-HT augmented the vasoconstrictions. The 5-CT sympatho-inhibition was reversed by 5-HT_1A plus 5-HT_1D antagonists (WAY-100,635 and LY310762, respectively), whereas ritanserin (5-HT_2A antagonist) blocked the α-methyl-5-HT potentiating effect. Norepinephrine-generated vasoconstrictions were increased or diminished by α-methyl-5-HT or 5-CT, respectively. 5-HT_1A/1D/2A receptors were expressed at vascular level, being 5-HT_1A expression increased by fluoxetine in diabetic rats.

SIGNIFICANCE

Our findings suggest that fluoxetine improves metabolic and renal profiles, changes the vasopressor responses, and 5-HT receptors modulating sympathetic activity in diabetic rats: 5-HT_1A/1D are involved in the sympatho-inhibition, while 5-HT_2A is implicated in the sympatho-potentiation, being both effects pre and/or postjunctional in nature.

High-fat diet induces depression-like phenotype via astrocyte-mediated hyperactivation of ventral hippocampal glutamatergic afferents to the nucleus accumbens

Comorbidity exists between metabolic disorders and depressive syndrome with unclear mechanisms. To characterize the causal relationship, we adopted a 12-week high-fat diet (HFD) to induce metabolic disorder and depressive phenotypes in mice. Initially, we identified an enhanced glutamatergic input in the nucleus accumbens of HFD mice. Retrograde tracing and chemogenetic inhibition showed that the hyperactive ventral hippocampal glutamatergic afferents to the nucleus accumbens determined the exhibition of depression-like behavior in HFD mice. Using lentiviral knockdown and overexpression approaches, we proved that HFD-induced downregulation of glial glutamate transporters, GLAST and GLT-1, contributed to the observed circuit maladaptations and subsequent depression-like behaviors. Finally, we identified a potential therapeutic agent, riluzole, which could mitigate the HFD-induced behavioral deficits by normalizing the expressions of GLAST and GLT-1 and ventral hippocampal glutamatergic afferents to the nucleus accumbens. Overall, astrocyte-mediated disturbance in glutamatergic transmission underlies the metabolic disorder-related depressive syndrome and represents a therapeutic target for this subtype of depressive mood disorders.

Effect of blueberry (Vaccinium virgatum) extract on depressive-like behavior and metabolic serum alterations in lipopolysaccharide-challenged mice

In the present study, we aimed to investigate the protective effect of blueberry extract on behavioral, biochemical, and morphological changes in an experimental model of lipopolysaccharide (LPS)-induced depressive behavior. Male Swiss mice were pretreated with the vehicle, fluoxetine (20 mg/kg), or Vaccinium virgatum extract (100 mg/kg and 200 mg/kg) for seven days. On day 7, the animals were administered an LPS injection (0.83 mg/kg) or vehicle. Pretreatment with blueberry extract prevented LPS-induced depressive-like behavior. Moreover, LPS increased serum levels of total cholesterol; however, V. virgatum did not prevent the increase in total cholesterol levels. Furthermore, the extract prevented the LPS-induced elevation in serum reactive oxygen species. Also, V. virgatum extract increased the HDL cholesterol levels. Additionally, this extract prevented the LPS-induced decrease in glucose levels and serum adenosine deaminase activity. Collectively, V. virgatum extract has a potential protective effect against changes similar to those observed in patients with depression. PRACTICAL APPLICATIONS: Vaccinium virgatum, popularly known as blueberry, has been effective in preventing or treating neuropsychiatric diseases owing to its antioxidant, anti-inflammatory, and neuroprotective properties. Fluoxetine is a known drug used to treat depression; however, its adverse effects result in therapeutic non-adherence. Thus, the search for new natural compounds possessing antidepressant activities while lacking adverse effects is crucial for identifying novel therapeutic alternatives against depression.