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European Journal of Pharmacology Jun 2024The purpose of this study was to determine the receptor subtype and the underlying mechanisms involved in the relaxant effect to leptin in mid- and late-pregnant mouse...
The purpose of this study was to determine the receptor subtype and the underlying mechanisms involved in the relaxant effect to leptin in mid- and late-pregnant mouse uterus. We determined the relative mRNA expression of receptor subtypes, eNOS, and BK channel by quantitative PCR and also the overall receptor expression by immunohistochemistry. Isometric tension studies were conducted to evaluate the effects of leptin and to delineate its mechanisms. A selective siRNA for the ObRb receptor was used to determine the participation of the receptor subtype in biochemical and molecular effects of leptin. The relaxant response to leptin was greater in mid-pregnancy compared to late pregnancy and was mediated by the activation of BK channels by eNOS-derived nitric oxide in an ObRb receptor-dependent manner. In comparison to mid-pregnancy, expression of short forms (mainly ObRa receptor) of the receptor was significantly increased in late pregnancy, whereas ObRb receptor expression was similar in both phases. The results of the study suggest that ObRb receptor mediates leptin-induced increase in eNOS expression and NO synthesis. Leptin-induced eNOS expression and activation cause cGMP-independent stimulation of BK channels causing uterine relaxation. Increased short forms of the receptors and reduced BK channels exert a negative effect on uterine relaxation in late pregnancy. Leptin may have a physiological role in maintaining uterine quiescence in mid-pregnancy and its reduced relaxant response in late gestation may facilitate labor. Further, ObRb receptor agonists may be useful in the management of preterm labor.
PubMed: 38945286
DOI: 10.1016/j.ejphar.2024.176796 -
Biochemical Pharmacology Jun 2024The peptide hormone relaxin plays a critical role in tissue remodeling in a variety of tissues through activation of its cognate receptor, RXFP1. Relaxin's ability to...
The peptide hormone relaxin plays a critical role in tissue remodeling in a variety of tissues through activation of its cognate receptor, RXFP1. Relaxin's ability to modify extracellular matrices has provided a strong rationale for treating fibrosis in a variety of tissues. Treatment with recombinant relaxin peptides in clinical studies of heart failure has not yet proven useful, likely due to the short half-life of infused peptide. To circumvent this particular pharmacokinetic pitfall we have used a Protein-in-Protein (PiP) antibody technology described previously, to insert a single-chain human relaxin construct into the complementarity-determining region (CDR) of an immunoglobulin G (IgG) backbone, creating a relaxin molecule with a half-life of ∼4-5 days in mice. Relaxin-PiP biologics displaced Europium-labeled human relaxin in RXFP1-expressing cells and demonstrated full agonist activity on both human and mouse RXFP1 receptors. Relaxin-PiPs did not show signal transduction bias, as they activated cAMP in THP-1 cells, and cGMP and pERK signaling in primary human cardiac fibroblasts. In an induced carbon tetrachloride mouse model of liver fibrosis one relaxin-PiP, R2-PiP, caused reduction of liver lesions, ameliorated collagen accumulation in the liver with the corresponding reduction of Collagen1a1 gene expression, and increased cell proliferation in hepatic parenchyma. These relaxin biologics represent a novel approach to the design of a long-acting RXFP1 agonist to probe the clinical utility of relaxin/RXFP1 signaling to treat a variety of human fibrotic diseases.
PubMed: 38945278
DOI: 10.1016/j.bcp.2024.116401 -
Biochemical Pharmacology Jun 2024β2-adrenergic receptor (β2AR) agonists are the clinical gold standard for treatment and prophylaxis of airway constriction in pulmonary obstructive diseases such as... (Review)
Review
β2-adrenergic receptor (β2AR) agonists are the clinical gold standard for treatment and prophylaxis of airway constriction in pulmonary obstructive diseases such as asthma and COPD. Inhaled β2-agonists elicit rapid bronchorelaxation of the airway smooth muscle, yet, clinical tachyphylaxis to this response can occur over repeated and chronic use, which reduces the bronchodilatory effectiveness. Several mechanisms have been proposed to impart β2-agonist tachyphylaxis, most notably β2AR desensitization. However, airway tissue is known to be highly oxidative, particularly in obstructive disease states where reactive oxygen species (ROS) generation is upregulated and ROS degradation is suboptimal yielding a large oxidative burden. Recent evidence demonstrates that β2AR can regulate ROS generation and that ROS can post-translationally alter β2AR cysteine residues via oxidation, leading to distinct functional receptor outcomes. Herein, we discuss the growing evidence for β2AR mediated ROS generation in airway cells and the role of ROS in regulating β2AR via cysteine-oxidation of the receptor. Given the functional consequence of the β2AR-ROS signaling axis in the airways, we also discuss the potential role of ROS in mediating β2-agonist tachyphylaxis.
PubMed: 38945277
DOI: 10.1016/j.bcp.2024.116403 -
Physiology & Behavior Jun 2024The roles of metabolic signals, including Glucagon-like peptide 1 (GLP-1), have been implicated in multiple domains outside metabolic regulation. There is a growing... (Review)
Review
INTRODUCTION
The roles of metabolic signals, including Glucagon-like peptide 1 (GLP-1), have been implicated in multiple domains outside metabolic regulation. There is a growing interest in repurposing Glucagon-like peptide 1 receptor agonists (GLP-1RAs) as therapeutics for motivation and reward-related behavioural disturbances. Herein, we aim to systematically review the extant evidence on the potential effects of GLP-1RAs on the reward system.
METHODS
The study followed PRISMA guidelines using databases such as OVID, PubMed, Scopus, and Google Scholar. The search focused on "Reward Behavior" and "Glucagon Like Peptide 1 Receptor Agonists" and was restricted to human studies. Quality assessment achieved by the NIH's Quality Assessment of Controlled Intervention Studies RESULTS: GLP-1RAs consistently reduced energy intake and influenced reward-related behaviour. These agents have been associated with decreased neurocortical activation in response to higher rewards and food cues, particularly high-calorie foods, and lowered caloric intake and hunger levels.
DISCUSSION
GLP-1RAs show promise in addressing reward dysfunction linked to food stimuli, obesity, and T2DM. They normalize insulin resistance, and might also modulate dopaminergic signalling and reduce anhedonia. Their effects on glycemic variability and cravings suggest potential applications in addiction disorders.
PubMed: 38945189
DOI: 10.1016/j.physbeh.2024.114622 -
Ophthalmology. Glaucoma May 2024
PubMed: 38944802
DOI: 10.1016/j.ogla.2024.03.005 -
Cancer Genomics & Proteomics 2024Uveal melanoma is an ocular malignancy whose prognosis severely worsens following metastasis. In order to improve the understanding of molecular physiology of metastatic...
BACKGROUND/AIM
Uveal melanoma is an ocular malignancy whose prognosis severely worsens following metastasis. In order to improve the understanding of molecular physiology of metastatic uveal melanoma, we identified genes and pathways implicated in metastatic vs non-metastatic uveal melanoma.
PATIENTS AND METHODS
A previously published dataset from Gene Expression Omnibus (GEO) was used to identify differentially expressed genes between metastatic and non-metastatic samples as well as to conduct pathway and perturbagen analyses using Gene Set Enrichment Analysis (GSEA), EnrichR, and iLINCS.
RESULTS
In male metastatic uveal melanoma samples, the gene LOC401052 is significantly down-regulated and FHDC1 is significantly up-regulated compared to non-metastatic male samples. In female samples, no significant differently expressed genes were found. Additionally, we identified many significant up-regulated immune response pathways in male metastatic uveal melanoma, including "T cell activation in immune response". In contrast, many top up-regulated female pathways involve iron metabolism, including "heme biosynthetic process". iLINCS perturbagen analysis identified that both male and female samples have similar discordant activity with growth factor receptors, but only female samples have discordant activity with progesterone receptor agonists.
CONCLUSION
Our results from analyzing genes, pathways, and perturbagens demonstrate differences in metastatic processes between sexes.
Topics: Humans; Uveal Neoplasms; Melanoma; Female; Male; Gene Expression Profiling; Neoplasm Metastasis; Gene Expression Regulation, Neoplastic; Transcriptome; Sex Factors
PubMed: 38944422
DOI: 10.21873/cgp.20452 -
International Journal of Cardiology Jun 2024The prevalence of HF with preserved ejection raction (HFpEF, with EF ≥50%) is increasing across all populations with high rates of hospitalization and mortality,... (Review)
Review
The prevalence of HF with preserved ejection raction (HFpEF, with EF ≥50%) is increasing across all populations with high rates of hospitalization and mortality, reaching up to 80% and 50%, respectively, within a 5-year timeframe. Comorbidity-driven systemic inflammation is thought to cause coronary microvascular dysfunction and increased epicardial adipose tissue, leading to downstream friborsis and molecular changes in the cardiomyocyte, leading to increased stiffness and diastolic dynsfunction. HFpEF poses unique challenges in terms of diagnosis due to its complex and diverse nature. The diagnosis of HFpEF relies on a combination of clinical assessment, imaging studies, and biomarkers. An additional important step in diagnosing HFpEF involves excluding certain cardiac diagnoses that may be specific underlying causes of HFpEF or may be masquerading as HFpEF and require specific alternative treatment approaches. In addition to administering sodium-glucose cotransporter 2 inhibitors to all patients, the most effective approach to enhance clinical outcomes may involve tailored therapy based on each patient's unique clinical profile. Exercise should be recommended for all patients to improve the quality of life. Glucagon-like peptide-1 1 agonists are a promising treatment option in obese HFpEF patients. Novel approaches targeting inflammation are also in early phase trials.
PubMed: 38944348
DOI: 10.1016/j.ijcard.2024.132304 -
Brazilian Journal of Anesthesiology... Jun 2024
PubMed: 38944239
DOI: 10.1016/j.bjane.2024.844538 -
Development of NR0B2 as a therapeutic target for the re-education of tumor associated myeloid cells.Cancer Letters Jun 2024Immune checkpoint blockade (ICB) has had limited utility in several solid tumors such as breast cancer, a major cause of cancer-related mortality in women. Therefore,...
Immune checkpoint blockade (ICB) has had limited utility in several solid tumors such as breast cancer, a major cause of cancer-related mortality in women. Therefore, there is considerable interest in alternate strategies to promote an anti-cancer immune response. A paper co-published in this issue describes how NR0B2, a protein involved in cholesterol homeostasis, functions within myeloid immune cells to modulate the inflammasome and reduce the expansion of immune-suppressive regulatory T cells (T). Here, we develop NR0B2 as a potential therapeutic target. NR0B2 in tumors is associated with improved survival for several cancer types including breast. Importantly, NR0B2 expression is also prognostic of ICB success. Within breast tumors, NR0B2 expression is inversely associated with FOXP3, a marker of T. While a described agonist (DSHN) had some efficacy, it required high doses and long treatment times. Therefore, we designed and screened several derivatives. A methyl ester derivative (DSHN-OMe) emerged as superior in terms of (1) cellular uptake, (2) ability to regulate expected expression of genes, (3) suppression of T expansion using in vitro co-culture systems, and (4) efficacy against the growth of primary and metastatic tumors. This work identifies NR0B2 as a target to re-educate myeloid immune cells and a novel ligand with significant anti-tumor efficacy in preclinical models.
PubMed: 38944231
DOI: 10.1016/j.canlet.2024.217086 -
Biological Psychiatry Jun 2024Most mental disorders involve dysfunction of the dorsolateral prefrontal cortex (dlPFC), a recently evolved brain region that subserves working memory, abstraction and... (Review)
Review
Most mental disorders involve dysfunction of the dorsolateral prefrontal cortex (dlPFC), a recently evolved brain region that subserves working memory, abstraction and the thoughtful regulation of attention, action and emotion. For example, schizophrenia, depression, long-COVID and Alzheimer's disease are all associated with dlPFC dysfunction, with neuropathology often focused in layer III. The dlPFC has extensive top-down projections: e.g. to the posterior association cortices to regulate attention, and the subgenual cingulate cortex via the rostral and medial PFC to regulate emotional responses. However, the dlPFC is particularly dependent on arousal state, and is very vulnerable to stress and inflammation, which are etiological and/or exacerbating factors in most mental disorders. The cellular mechanisms by which stress and inflammation impact the dlPFC are a topic of current research, and are summarized in this review. For example, the layer III dlPFC circuits generating working memory-related neuronal firing have unusual neurotransmission, depending on NMDAR and nicotinic-α7R actions that are blocked under inflammatory conditions by kynurenic acid. These circuits also have unusual neuromodulation, with the molecular machinery to magnify calcium signaling in spines needed to support persistent firing, which must be tightly regulated to prevent toxic calcium actions. Stress rapidly weakens layer III connectivity by driving feedforward calcium-cAMP opening of potassium channels on spines. This is regulated by postsynaptic noradrenergic α2A-AR and mGluR3 signaling, but dysregulated by inflammation and/or chronic stress exposure, contributing to spine loss. Treatments that strengthen dlPFC, via pharmacological (the α2A-AR agonist, guanfacine) or rTMS manipulation, provide a rational basis for therapy.
PubMed: 38944141
DOI: 10.1016/j.biopsych.2024.06.016