Role of astrocyte senescence regulated by the non- canonical autophagy in the neuroinflammation associated to cerebral malaria

Astrocytic HSP60 Deletion Induced Astrocyte Senescence and Inhibited Neuroregeneration via Modulating the S1P/Truncated-BDNF Pathway

Heat Shock Protein 60 (HSP60) plays a critical role in maintaining mitochondrial function in astrocytes and has a significant impact on central nervous system (CNS) health. However, how HSP60 regulates the mitochondrial function of astrocytes to inhibit neuroregeneration remains unknown. In this study, we generated astrocyte-specific HSP60 knockout male mice to investigate the consequences of HSP60 deficiency. Firstly, our results confirmed that HSP60 deficiency caused abnormal expression of mitochondrial function-related genes, causing significant mitochondrial dysfunction, which triggered cellular senescence in astrocytes. Moreover, the alterations of 5-hydroxytryptamine 2A receptor (5-HT2AR), glucocorticoid receptor (GR), dopamine D2 receptor (D2R), and N-methyl-D-aspartate receptor subunit 2A (NR2A) expression suggested a disruption in neurotransmission and synaptic plasticity. Additionally, the increased levels of site-1 protease (S1P), truncated brain-derived neurotrophic factor (truncated-BDNF), and synaptophysin indicate synaptic structural and functional impairments. Expectedly, our findings demonstrated mitochondrial dysfunction and cellular senescence in astrocytes, leading to altered expression of neurotransmitter receptors in the cortex, as well as reduced neuronal numbers and neurotransmitter levels in the hippocampus after the deletion of HSP60 in astrocytes of the male mice. Notably, Urolithin A (UA) and the S1P inhibitor, PF429242, were found to alleviate astrocyte senescence and promote neuronal regeneration by inhibiting truncated BDNF expression. In conclusion, our study revealed that HSP60 deficiency in astrocytes induces mitochondrial dysfunction and cellular senescence via the S1P/truncated-BDNF pathway, resulting in disrupted neurotransmitter receptor expression, synaptic protein alterations, and impaired neuroregeneration. These insights underscored the importance of HSP60 in CNS health and provided promising avenues for developing treatments for neurodegenerative disorders.

Berberine Inhibits the Disruption of the Blood-Brain Barrier and Glial Cell Activation in a Rat Model of Acute Hepatic Encephalopathy

BACKGROUND AND AIM

Hepatic encephalopathy (HE) is a complex neurological disorder in individuals with liver diseases, necessitating effective neuroprotective interventions to alleviate its adverse outcomes. Berberine (BBR), a natural compound with well-established anti-fibrotic and neuroprotective properties, has not been extensively studied in the context of glial activation under hyperammonaemic conditions. This study evaluates the neuroprotective potential of BBR in a thioacetamide (TAA)-induced HE rat model, focusing on its effects on glial activation and NLRP3 inflammasome signalling.

METHODS

Neurological impairments were assessed using open field tests and sensory analysis. Western blotting was performed to evaluate the expression of glial and neuronal markers, tight junction proteins and NLRP3 inflammasome components in the cortex and hippocampus. Histopathological and molecular changes were further examined using H&E, immunohistochemistry and immunofluorescence staining.

KEY RESULTS

BBR treatment significantly improved behavioural abnormalities and reduced systemic ammonia levels in TAA-exposed rats. It restored blood-brain barrier integrity, as evidenced by reduced tight junction protein degradation. BBR inhibited the expression of NLRP3 inflammasome markers, including caspase-1, IL-1β, ASC, and NF-κB, while reducing glial cell activation (IBA-1 and GFAP). Notably, BBR diminished NLRP3 expression in glial cells, indicating its potent anti-inflammatory effects. Additionally, BBR preserved neuronal integrity, as demonstrated by the maintained expression of MAP-2 and NeuN and reduced cleaved Gasdermin D levels.

CONCLUSIONS

These findings suggest that BBR alleviates behavioural and molecular abnormalities in HE through NLRP3 inflammasome inhibition, highlighting its potential as a therapeutic agent for managing HE.

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.