Small Molecule Modulators of β-arrestins.

Unlabelled: β-arrestins (βarrs) are key regulators of G protein-coupled receptors (GPCRs), essential for modulating signaling pathways and physiological processes. While current pharmacological strategies target GPCR orthosteric and allosteric sites, as well as G protein transducers, comparable tools for studying βarrs are lacking. Here, we present the discovery and characterization of novel small-molecule allosteric inhibitors of βarrs through comprehensive biophysical, biochemical, pharmacological, and structural analyses.

Modulation of the endocannabinoid system by (S)-ketamine in an animal model of depression.

Ketamine (KET) is recognized as rapid-acting antidepressant, but its mechanisms of action remain elusive. Considering the role of endocannabinoids (eCB) in stress and depression, we investigated if S-KET antidepressant effects involve the regulation of the eCB system using an established rat model of depression based on selective breeding: the Flinders Sensitive Line (FSL) and their controls, the Flinders Resistant Line (FRL). S-KET (15 mg/kg) effects were assessed in rats exposed to the open field and forced swimming test (FST), followed by analysis of the eCB signaling in the rat prefrontal cortex (PFC), a brain region involved in depression neurobiology.

Heterobivalent Dual-Target Peptide for Integrin-αβ and Neuropeptide Y Receptors on Breast Tumor.

Heterodimer peptides targeting more than one receptor can be advantageous, as tumors can simultaneously express more than one receptor type. For human breast cancer, a promising biological target is tumor angiogenesis through αβ integrin expression. Another promising target is Neuropeptide Y receptors, considering YR is overexpressed in 90% of human breast tumors.

Acute transcutaneous auricular vagus nerve stimulation modulates presynaptic SV2A density in healthy rat brain: An in vivo microPET study.

Vagus nerve stimulation (VNS) is the subject of exploration as an adjunct treatment for neurological disorders such as epilepsy, chronic migraine, pain, and depression. A non-invasive form of VNS is transcutaneous auricular VNS (taVNS). Combining animal models and positron emission tomography (PET) may lead to a better understanding of the elusive mechanisms of taVNS.

Immunotherapeutic potential of collagen V oral administration in mBSA/CFA-induced arthritis.

We hypothesized that after synovial injury, collagen V (Col V) expose occult antigens, and Col V autoantibodies develop, indicating the loss of immune tolerance against this molecule, thus leading to damage to mesenchymal-derived cells as well as the extracellular matrix in experimental arthritis. Thus, the present study investigated the effects of oral administration of Col V on the synovium after the development of inflammation in mBSA/CFA-induced arthritis. After fourteen days of intraarticular administration of mBSA, 10 male Lewis rats were orally administered Col V (500 μg/300 μL) diluted in 0.

Green Nanotechnology Through Papain Nanoparticles: Preclinical in vitro and in vivo Evaluation of Imaging Triple-Negative Breast Tumors.

Background: Recent advancements in nanomedicine and nanotechnology have expanded the scope of multifunctional nanostructures, offering innovative solutions for targeted drug delivery and diagnostic agents in oncology and nuclear medicine. Nanoparticles, particularly those derived from natural sources, hold immense potential in overcoming biological barriers to enhance therapeutic efficacy and diagnostic accuracy. Papain, a natural plant protease derived from , emerges as a promising candidate for green nanotechnology-based applications due to its diverse medicinal properties, including anticancer properties.

Glucocorticoid modulates oxidative and thermogenic function of rat brown adipose tissue and human brown adipocytes.

Chronic and excessive glucocorticoid (GC) exposure can cause Cushing's syndrome, resulting in fat accumulation in selected body areas. Particularly in the brown adipose tissue (BAT), GC acts negatively, resulting in whitening of the tissue. We hypothesized that dysregulation of microRNAs by GC could be an additional mechanism to explain its negative actions in BAT.

Mitigating jaw osteonecrosis: bioactive glass and pericardial membrane combination in a rat model.

Objectives: Bisphosphonates (BFs) show clinical effectiveness in managing osteoporosis and bone metastases but pose risks of bisphosphonate-related jaw osteonecrosis (BRONJ). With no established gold standard for BRONJ treatment, our focus is on symptom severity reduction. We aimed to assess the preventive effects of bioactive glass and/or pericardial membrane in a preclinical BRONJ model, evaluating their potential to prevent osteonecrosis and bone loss post-tooth extractions in zoledronic acid (ZA)-treated animals.

Impact of cannabidiol on brain glucose metabolism of C57Bl/6 male mice previously exposed to cocaine.

Despite evidence of the beneficial effects of cannabidiol (CBD) in animal models of cocaine use disorder (CUD), CBD neuronal mechanisms remain poorly understood. This study investigated the effects of CBD treatment on brain glucose metabolism, in a CUD animal model, using [F]FDG positron emission tomography (PET). Male C57Bl/6 mice were injected with cocaine (20 mg/kg, i.

Sex-specific regulation of miR-22 and ERα in white adipose tissue of obese dam's female offspring impairs the early postnatal development of functional beige adipocytes in mice.

During inguinal adipose tissue (iWAT) ontogenesis, beige adipocytes spontaneously appear between postnatal 10 (P10) and P20 and their ablation impairs iWAT browning capacity in adulthood. Since maternal obesity has deleterious effects on offspring iWAT function, we aimed to investigate its effect in spontaneous iWAT browning in offspring. Female C57BL/6 J mice were fed a control or obesogenic diet six weeks before mating.

[F]FDG and [C]PK11195 PET imaging in the evaluation of brown adipose tissue - effects of cold and pharmacological stimuli and their association with crotamine intake in a male mouse model.

Unlabelled: This study aimed to evaluate the role of positron emission tomography (PET) with [C]PK11195 and [F]FDG in the characterization of brown adipose tissue (BAT).

Methods: Male C57BL/6 mice were studied with the glucose analogue [F]FDG (n = 21) and the TSPO mitochondrial tracer [C]PK11195 (n = 28), without stimulus and after cold (6-9 °C) or beta-agonist (CL316243) stimuli. PET studies were performed at baseline and after 21 days of daily treatment with crotamine, which is a peptide described to induce adipocyte tissue browning and to increase BAT metabolism.

Treadmill exercise modulates nigral and hippocampal cannabinoid receptor type 1 in the 6-OHDA model of Parkinson's disease.

Physical exercise benefits Parkinson's disease (PD) patients but the mechanism is unclear. Cannabinoid receptor type 1 (CB1R) is known to be reduced in PD patients and animal models. We test the hypothesis that binding of the CB1R inverse agonist, [H]SR141716A, is normalized by treadmill exercise in the toxin-induced 6-hydroxydopamine (6-OHDA) model of PD.

A single dose of cocaine raises SV2A density in hippocampus of adolescent rats.

Objective: Cocaine is a highly addictive psychostimulant that affects synaptic activity with structural and functional adaptations of neurons. The transmembrane synaptic vesicle glycoprotein 2A (SV2A) of pre-synaptic vesicles is commonly used to measure synaptic density, as a novel approach to the detection of synaptic changes. We do not know if a single dose of cocaine suffices to affect pre-synaptic SV2A density, especially during adolescence when synapses undergo intense maturation.

Selecting the Best Animal Model of Parkinson's Disease for Your Research Purpose: Insight from PET Imaging Studies.

Parkinson's disease (PD) is a debilitating neurodegenerative multisystem disorder leading to motor and non-motor symptoms in millions of individuals. Despite intense research, there is still no cure, and early disease biomarkers are lacking. Animal models of PD have been inspired by basic elements of its pathogenesis, such as dopamine dysfunction, alpha-synuclein accumulation, neuroinflammation and disruption of protein degradation, and these have been crucial for a deeper understanding of the mechanisms of pathology, the identification of biomarkers, and evaluation of novel therapies.

Potential of [C]()-PK11195 PET Imaging for Evaluating Tumor Inflammation: A Murine Mammary Tumor Model.

Background: Breast tumor inflammation is an immunological process that occurs mainly by mediation of Tumor-Associated Macrophages (TAM). Aiming for a specific measurement of tumor inflammation, the current study evaluated the potential of Positron Emission Tomography (PET) imaging with [C]()-PK11195 to evaluate tumor inflammation in a mammary tumor animal model.

Methods: Female Balb/C mice were inoculated with 4T1 cells.

[ F]FDG brain uptake of C57Bl/6 male mice is affected by locomotor activity after cocaine use: A small animal positron emission tomography study.

We verified if cocaine-induced peripheral activation might disrupt [ F]FDG brain uptake after a cocaine challenge and suggested an optimal protocol to measure cocaine-induced brain metabolic alterations in mice. C57Bl/6 male mice were injected with [ F]FDG and randomly separated into three groups. Groups 1 and 2 were kept conscious after [ F]FDG administration and after 5 min received saline or cocaine (20 mg/kg).

Spontaneous partial recovery of striatal dopaminergic uptake despite nigral cell loss in asymptomatic MPTP-lesioned female minipigs.

The Göttingen minipig is a large animal with a gyrencephalic brain that expresses -complex behavior, making it an attractive model for Parkinson's disease research. Here, we investigate the temporal evolution of presynaptic dopaminergic function for 14 months after injections of 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) into the minipig using a multi-tracer longitudinal positron emission tomography (PET) design. We injected seven sedated minipigs with 1-2 mg/kg of MPTP, and two with saline, three times a week over four weeks.

Cannabidiol Treatment Improves Glucose Metabolism and Memory in Streptozotocin-Induced Alzheimer's Disease Rat Model: A Proof-of-Concept Study.

An early and persistent sign of Alzheimer's disease (AD) is glucose hypometabolism, which can be evaluated by positron emission tomography (PET) with F-2-fluoro-2-deoxy-D-glucose ([F]FDG). Cannabidiol has demonstrated neuroprotective and anti-inflammatory properties but has not been evaluated by PET imaging in an AD model. Intracerebroventricular (icv) injection of streptozotocin (STZ) is a validated model for hypometabolism observed in AD.

The effects of treadmill exercise in animal models of Parkinson's disease: A systematic review.

Parkinson's disease (PD) is a progressive disabling brain disorder. Physical exercise has been shown to alleviate the symptoms of PD and, consequently, improve patient quality of life. Exercise mechanisms involved in beneficial effects on PD have been widely investigated.

Neuroplasticity induced by the retention period of a complex motor skill learning in rats.

Learning complex motor skills is an essential process in our daily lives. Moreover, it is an important aspect for the development of therapeutic strategies that refer to rehabilitation processes since motor skills previously acquired can be transferred to similar tasks (motor skill transfer) or recovered without further practice after longer delays (motor skill retention). Different acrobatic exercise training (AE) protocols induce plastic changes in areas involved in motor control and improvement in motor performance.

Active lifestyle enhances protein expression profile in subjects with Lewy body pathology.

Unlabelled: Clinical trials of the effects of physical activity have reported improvements in symptoms and quality of life in patients with Parkinson's disease (PD). Additionally, morphological brain changes after exercising were reported in PD animal models. However, these lifestyle-related changes were not evaluated in postmortem brain tissue.

C-PK11195 plasma metabolization has the same rate in multiple sclerosis patients and healthy controls: a cross-sectional study.

C-PK11195 is a positron emitter tracer used for Positron Emission Tomography (PET) imaging of innate immune cell activation in studies of neuroinflammatory diseases. For the image quantitative analysis, it is necessary to quantify the intact fraction of this tracer in the arterial plasma during imaging acquisition (plasma intact fraction). Due to the complexity and costs involved in this analysis it is important to evaluate the real necessity of individual analysis in each C-PK11195 PET imaging acquisition.

Positron Emission Tomography Imaging for In Vivo Measuring of Myelin Content in the Lysolecithin Rat Model of Multiple Sclerosis.

Multiple sclerosis (MS) is a neuroinflammatory disease with expanding axonal and neuronal degeneration and demyelination in the central nervous system, leading to motor dysfunctions, psychical disability, and cognitive impairment during MS progression. Positron emission tomography (PET) is an imaging technique able to quantify in vivo cellular and molecular alterations. Radiotracers with affinity to intact myelin can be used for in vivo imaging of myelin content changes over time.

miRNA-22 deletion limits white adipose expansion and activates brown fat to attenuate high-fat diet-induced fat mass accumulation.

Background: Obesity, characterized by excessive expansion of white adipose tissue (WAT), is associated with numerous metabolic complications. Conversely, brown adipose tissue (BAT) and beige fat are thermogenic tissues that protect mice against obesity and related metabolic disorders. We recently reported that deletion of miR-22 enhances energy expenditure and attenuates WAT expansion in response to a high-fat diet (HFD).