Projection length stimulated by oxytocin is modulated by the inhibition of calcium signaling in U-87MG cells

Characterization of functionally relevant G protein-coupled receptors in endometriotic epithelial cells

Endometriosis is a chronic inflammatory disease characterized by the invasion of endometrial cells outside the uterine cavity. Current treatments for the disease, whose typical symptoms are pain and infertility, are unsatisfactory, relying on the surgical removal of the lesions and hormonal therapies with high symptom relapse and collateral effects, respectively. The aim of the present study was to exploit the rationale for G protein-coupled receptors (GPCRs) as non-hormonal therapeutic targets for this disease. To this end, human endometriotic epithelial cells 12Z were employed to characterize GPCR-mediated increases in intracellular Ca2+ concentrations ([Ca2+]i) using fluo-4, and cell invasion was measured using Boyden chamber assays. The results showed that the GPCR ligands oxytocin, bradykinin, histamine, lysophosphatidic acid, and sphingosine 1-phosphate (S1P) efficiently increased [Ca2+]i and induced cell invasion in endometriotic cells. In contrast, neuropeptide S, previously identified as a pro-invasive mediator, did not increase [Ca2+]i in 12Z cells. Notably, pretreatment with pertussis toxin significantly reduced S1P-dependent [Ca2+]i increase and cell invasion, highlighting the involvement of Gi-mediated signaling. Employing specific agonists and/or antagonists of S1P receptor isoforms, we demonstrated that S1P1/S1P3/S1P5, but not S1P2/S1P4 mediated the [Ca2+]i increases in this cellular model. Moreover, activation of S1P1/S1P4/S1P5, but not S1P2/S1P3, efficiently stimulated cell invasion. Taken together, we identified several GPCRs that are functionally relevant in human endometriotic epithelial cells and may potentially serve as targets for non-hormonal therapy of endometriosis.

Oxytocin Protects PC12 Cells Against β-Amyloid-Induced Cell Injury

Background/Objectives: Neurodegenerative diseases, particularly Alzheimer's disease (AD), are characterized by progressive cognitive decline and non-cognitive symptoms that significantly affect health and quality of life. Beta-amyloid (Aβ) protein accumulation is a key factor in AD pathology, leading to neuronal damage. Oxytocin (OXT), a neuropeptide with neuroprotective potential, has garnered interest owing to its ability to mitigate neurotoxicity. We hypothesized that oxytocin could protect PC12 cells from Aβ-induced cytotoxicity through antioxidant effects and modulation of apoptotic pathways (i.e., mitochondrial and MAPK pathways). In this study, we aim to assess oxytocin's protective effects on cell viability, oxidative stress, mitochondrial function, and apoptotic signaling. Methods: PC12 cells were treated with Aβ25-35 and pre-treated with varying oxytocin concentrations to assess cell viability, reactive oxygen species (ROS) generation, and mitochondrial membrane potential. Western blotting was performed to analyze the effects on mitochondrial apoptosis and MAPK pathways. Results: Oxytocin treatment significantly improved cell viability in a dose-dependent manner and reduced Aβ-induced oxidative stress and mitochondrial dysfunction. Oxytocin-treated groups exhibited decreased ROS levels, increased mitochondrial membrane potential, and modulation of apoptosis-related proteins. Oxytocin upregulated phosphorylated ERK1/2 and Bcl-2 while downregulating BAX and caspase-3, reducing the BAX/Bcl-2 ratio. Conclusions: Oxytocin effectively protects PC12 cells from Aβ-induced neurotoxicity, highlighting its potential as a therapeutic agent for AD. Further research is needed to clarify oxytocin's mechanisms and clinical implications in AD treatment.

Oxytocin Receptor Expression in Hair Follicle Stem Cells: A Promising Model for Biological and Therapeutic Discovery in Neuropsychiatric Disorders

The intricate nature of the human brain and the limitations of existing model systems to study molecular and cellular causes of neuropsychiatric disorders represent a major challenge for basic research. The promising progress in patient-derived stem cell technology and in our knowledge on the role of the brain oxytocin (OXT) system in health and disease offer new possibilities in that direction. In this study, the rat hair follicle stem cells (HFSCs) were isolated and expanded in vitro. The expression of oxytocin receptors (OXTR) was evaluated in these cells. The cellular viability was assessed 12 h post stimulation with OXT. The activation of OXTR-coupled intracellular signaling cascades, following OXT treatment was determined. Also, the influence of OXT on neurite outgrowth and cytoskeletal rearrangement were defined. The assessment of OXTR protein expression revealed this receptor is expressed abundantly in HFSCs. As evidenced by the cell viability assay, no adverse or cytotoxic effects were detected following 12 h treatment with different concentrations of OXT. Moreover, OXTR stimulation by OXT resulted in ERK1/2, CREB, and eEF2 activation, neurite length alterations, and cytoskeletal rearrangements that reveal the functionality of this receptor in HFSCs. Here, we introduced the rat HFSCs as an easy-to-obtain stem cell model that express functional OXTR. This cell-based model can contribute to our understanding of the progression and treatment of neuropsychiatric disorders with oxytocinergic system deficiency.

[Emergent role of astrocytes in oxytocin-mediated modulatory control of neuronal circuits and brain functions]

The neuropeptide oxytocin has been in the focus of scientists for decades due to its profound and pleiotropic effects on physiology, activity of neuronal circuits and behaviors. Until recently, it was believed that oxytocinergic action exclusively occurs through direct activation of neuronal oxytocin receptors. However, several studies demonstrated the existence and functional relevance of astroglial oxytocin receptors in various brain regions in the mouse and rat brain. Astrocytic signaling and activity are critical for many important physiological processes including metabolism, neurotransmitter clearance from the synaptic cleft and integrated brain functions. While it can be speculated that oxytocinergic action on astrocytes predominantly facilitates neuromodulation via the release of gliotransmitters, the precise role of astrocytic oxytocin receptors remains elusive. In this review, we discuss the latest studies on the interaction between the oxytocinergic system and astrocytes, and give details of underlying intracellular cascades.

Emerging role of astrocytes in oxytocin-mediated control of neural circuits and brain functions

The neuropeptide oxytocin has been in the focus of scientists for decades due to its profound and pleiotropic effects on physiology, activity of neuronal circuits and behaviors, among which sociality. Until recently, it was believed that oxytocinergic action exclusively occurs through direct activation of neuronal oxytocin receptors. However, several studies demonstrated the existence and functional relevance of astroglial oxytocin receptors in various brain regions in the mouse and rat brain. Astrocytic signaling and activity is critical for many important physiological processes including metabolism, neurotransmitter clearance from the synaptic cleft and integrated brain functions. While it can be speculated that oxytocinergic action on astrocytes predominantly facilitates neuromodulation via the release of specific gliotransmitters, the precise role of astrocytic oxytocin receptors remains elusive. In this review, we discuss the latest studies on the interaction between the oxytocinergic system and astrocytes, including detailed information about intracellular cascades, and speculate about future research directions on astrocytic oxytocin signaling.

Cell proliferation and anti-oxidant effects of oxytocin and oxytocin receptors: role of extracellular signal-regulating kinase in astrocyte-like cells

OBJECTIVES

Oxytocin (OXT) participates in various physiological functions ranging from reproduction to social and non-social behaviors. Recent studies indicate that OXT affects cell growth and metabolism. Here we characterized the growth stimulating and antioxidant actions of OXT and of OXT receptors (OXTR) in a glial cell-line (U-87MG).

METHODS

We developed an OXTR-knockdown cell-line (U-87MG KD) to establish the receptor specificity of OXT's actions, and the impact of lacking OXTR on growth and survival in glial cells. The role Extracellular-Signal Regulated Kinases (ERK1/2) on glial cell protection against consequences of oxidative stress, and cell proliferation was investigated.

RESULTS

In U-87MG cells, OXT stimulated cell proliferation and increased ERK1/2 phosphorylation. The specific ERK1/2 inhibitor, PD098059, produced marked inhibition of cell proliferation, and antagonized the stimulating effect of OXT on ERK1/2 phosphorylation and on cell proliferation. Slower growth rates and lower levels of phosphorylated ERK1/2 were observed in OXTR-knockdown cells and in U-87MG cells treated with an OXTR antagonist (L-371,257). In addition to increasing cell proliferation, OXT significantly blunted the rise in reactive oxygen species induced by H2O2, and antagonized the reductions in cell viability induced by H2O2 and camptothecin. The cell protective and antioxidant actions of OXT in U-87MG cells were not observed in the OXTR-knockdown cells.

CONCLUSION

OXT stimulates the growth of astrocyte-like cells acting on OXTR via ERK1/2 phosphorylation. The protection against apoptosis and the antioxidant capacity of OXT may contribute to the observed increase in cell proliferation. Oxytocin and OXTR appear to be fundamental for cell growth and viability of glial cells.

Myocyte Enhancer Factor 2A (MEF2A) Defines Oxytocin-Induced Morphological Effects and Regulates Mitochondrial Function in Neurons

The neuropeptide oxytocin (OT) is a well-described modulator of socio-emotional traits, such as anxiety, stress, social behavior, and pair bonding. However, when dysregulated, it is associated with adverse psychiatric traits, such as various aspects of autism spectrum disorder (ASD). In this study, we identify the transcription factor myocyte enhancer factor 2A (MEF2A) as the common link between OT and cellular changes symptomatic for ASD, encompassing neuronal morphology, connectivity, and mitochondrial function. We provide evidence for MEF2A as the decisive factor defining the cellular response to OT: while OT induces neurite retraction in MEF2A expressing neurons, OT causes neurite outgrowth in absence of MEF2A. A CRISPR-Cas-mediated knockout of MEF2A and retransfection of an active version or permanently inactive mutant, respectively, validated our findings. We also identified the phosphatase calcineurin as the main upstream regulator of OT-induced MEF2A signaling. Further, MEF2A signaling dampens mitochondrial functioning in neurons, as MEF2A knockout cells show increased maximal cellular respiration, spare respiratory capacity, and total cellular ATP. In summary, we reveal a central role for OT-induced MEF2A activity as major regulator of cellular morphology as well as neuronal connectivity and mitochondrial functioning, with broad implications for a potential treatment of disorders based on morphological alterations or mitochondrial dysfunction.