RGS5 augments astrocyte activation and facilitates neuroinflammation via TNF signaling

NR1H4 ameliorates Parkinson's disease via inhibiting astrocyte activation and neuroinflammation in a CEBPβ/NF-κB dependent manner

Parkinson's Disease (PD) is a degenerative disease driven by neuroinflammation. Nuclear receptor subfamily 1 group H member 4 (NR1H4), a nuclear receptor involved in metabolic and inflammatory regulation, is found to be widely expressed in central nervous system. Previous studies suggested the protective role of NR1H4 in various diseases related to inflammation, whether NR1H4 participates in PD progression remains unknown. To investigate the role of NR1H4 in neuroinflammation regulation, especially astrocyte activation during PD, siRNA and adenovirus were used to manipulate Nr1h4 expression. RNA-sequencing (RNA-seq), quantitative real-time PCR, enzyme-linked immunosorbent assay, Chromatin immunoprecipitation and western blotting were performed to further study the underlying mechanisms. We identified that NR1H4 was down-regulated during PD progression. In vitro experiments suggested that Nr1h4 knockdown led to inflammatory response, reactive oxygen species generation and astrocytes activation whereasNr1h4 overexpressionhad the opposite effects. The results of RNA-seq on astrocytes revealed that NR1H4 manipulated neuroinflammation in a CEBPβ/NF-κB dependent manner. Additionally, pharmacological activation of NR1H4 via Obeticholic acid ameliorated neuroinflammation and promoted neuronal survival. Our study first proved the neuroprotective effects of NR1H4against PD via inhibiting astrocyte activation and neuroinflammation in a CEBPβ/NF-κB dependent manner.

Early life adversity promotes gastrointestinal dysfunction through a sex-dependent phenotypic switch in enteric glia

Irritable bowel syndrome and related disorders of gut-brain interaction (DGBI) are common and exhibit a complex, poorly understood etiology that manifests as abnormal gut motility and pain. Risk factors such as biological sex, stressors during critical periods, and inflammation are thought to influence DGBI vulnerability by reprogramming gut-brain circuits, but the specific cells affected are unclear. Here, we used a model of early life stress to understand cellular mechanisms in the gut that produce DGBIs. Our findings identify enteric glia as a key cellular substrate in which stress and biological sex converge to dictate DGBI susceptibility. Enteric glia exhibit sexual dimorphism in genes and functions related to cellular communication, inflammation, and disease susceptibility. Experiencing early life stress has sex-specific effects on enteric glia that cause a phenotypic switch in male glia toward a phenotype normally observed in females. This phenotypic transformation is followed by physiological changes in the gut, mirroring those observed in DGBI in humans. These effects are mediated, in part, by alterations to glial prostaglandin and endocannabinoid signaling. Together, these data identify enteric glia as a cellular integration site through which DGBI risk factors produce changes in gut physiology and suggest that manipulating glial signaling may represent an attractive target for sex-specific therapeutic strategies in DGBIs.

Polydopamine-Coated Kaempferol-Loaded MOF Nanoparticles: A Novel Therapeutic Strategy for Postoperative Neurocognitive Disorder

Purpose

The primary objective of this study was to develop an innovative nanomedicine-based therapeutic strategy to alleviate Postoperative Neurocognitive Disorder (PND) in patients undergoing surgery.

Patients and Methods

To achieve this goal, polydopamine-coated Kaempferol-loaded Metal-Organic Framework nanoparticles (pDA/KAE@ZIF-8) were synthesized and evaluated. The study involved encapsulating Kaempferol (KAE) within ZIF-8 nanoparticles, followed by coating with polydopamine (PDA) to enhance biocompatibility and targeted delivery. The characterization of these nanoparticles (NPs) was conducted using various techniques including Scanning Electron Microscopy, Fourier-Transform Infrared Spectroscopy, X-ray Diffraction, and Ultraviolet-Visible spectroscopy. The efficacy of pDA/KAE@ZIF-8 NPs was tested in both in vitro and in vivo models, specifically focusing on their ability to penetrate the blood-brain barrier and protect neuronal cells against oxidative stress.

Results

The study found that pDA/KAE@ZIF-8 NPs efficiently penetrated the blood-brain barrier and were significantly taken up by neuronal cells. These nanoparticles demonstrated remarkable Reactive Oxygen Species (ROS) scavenging capabilities and stability under physiological conditions. In vitro studies showed that pDA/KAE@ZIF-8 NPs provided protection to HT-22 neuronal cells against H2O2-induced oxidative stress, reduced the levels of pro-inflammatory cytokines, and decreased apoptosis rates. In a PND mouse model, the treatment with pDA/KAE@ZIF-8 NPs significantly improved cognitive functions, surpassing the effects of KAE alone. This improvement was substantiated through behavioral tests and a noted reduction in hippocampal inflammation.

Conclusion

The findings from this study underscore the potential of pDA/KAE@ZIF-8 NPs as an effective nanotherapeutic agent for PND. This approach offers a novel direction in the postoperative care of elderly patients, with the potential to transform the therapeutic landscape for neurocognitive disorders following surgery. The application of nanotechnology in this context opens new avenues for more effective and targeted treatments, thereby improving the quality of life for patients suffering from PND.

The Interplay between Ferroptosis and Neuroinflammation in Central Neurological Disorders

Central neurological disorders are significant contributors to morbidity, mortality, and long-term disability globally in modern society. These encompass neurodegenerative diseases, ischemic brain diseases, traumatic brain injury, epilepsy, depression, and more. The involved pathogenesis is notably intricate and diverse. Ferroptosis and neuroinflammation play pivotal roles in elucidating the causes of cognitive impairment stemming from these diseases. Given the concurrent occurrence of ferroptosis and neuroinflammation due to metabolic shifts such as iron and ROS, as well as their critical roles in central nervous disorders, the investigation into the co-regulatory mechanism of ferroptosis and neuroinflammation has emerged as a prominent area of research. This paper delves into the mechanisms of ferroptosis and neuroinflammation in central nervous disorders, along with their interrelationship. It specifically emphasizes the core molecules within the shared pathways governing ferroptosis and neuroinflammation, including SIRT1, Nrf2, NF-κB, Cox-2, iNOS/NO·, and how different immune cells and structures contribute to cognitive dysfunction through these mechanisms. Researchers' findings suggest that ferroptosis and neuroinflammation mutually promote each other and may represent key factors in the progression of central neurological disorders. A deeper comprehension of the common pathway between cellular ferroptosis and neuroinflammation holds promise for improving symptoms and prognosis related to central neurological disorders.

Modulation of Type 5 Metabotropic Glutamate Receptor-Mediated Intracellular Calcium Mobilization by Regulator of G Protein Signaling 4 (RGS4) in Cultured Astrocytes

Acting as GTPase activating proteins promoting the silencing of activated G-proteins, regulators of G protein signaling (RGSs) are generally considered negative modulators of cell signaling. In the CNS, the expression of RGS4 is altered in diverse pathologies and its upregulation was reported in astrocytes exposed to an inflammatory environment. In a model of cultured cortical astrocytes, we herein investigate the influence of RGS4 on intracellular calcium signaling mediated by type 5 metabotropic glutamate receptor (mGluR5), which is known to support the bidirectional communication between neurons and glial cells. RGS4 activity was manipulated by exposure to the inhibitor CCG 63802 or by infecting the cells with lentiviruses designed to achieve the silencing or overexpression of RGS4. The pharmacological inhibition or silencing of RGS4 resulted in a decrease in the percentage of cells responding to the mGluR5 agonist DHPG and in the proportion of cells showing typical calcium oscillations. Conversely, RGS4-lentivirus infection increased the percentage of cells showing calcium oscillations. While the physiological implication of cytosolic calcium oscillations in astrocytes is still under investigation, the fine-tuning of calcium signaling likely determines the coding of diverse biological events. Indirect signaling modulators such as RGS4 inhibitors, used in combination with receptor ligands, could pave the way for new therapeutic approaches for diverse neurological disorders with improved efficacy and selectivity.