Background: It is widely accepted that mitochondria have a direct impact on neuronal function and survival. Oxidative stress caused by mitochondrial abnormalities play an important role in the pathophysiology of lipopolysaccharide (LPS)-induced memory impairment. Elamipretide (SS-31) is a novel mitochondrion-targeted antioxidant. However, the impact of elamipretide on the cognitive sequelae of inflammatory and oxidative stress is unknown. Methods: We utilized MWM and contextual fear conditioning test to assess hippocampus-related learning and memory performance. Molecular biology techniques and ELISA were used to examine mitochondrial function, oxidative stress, and the inflammatory response. TUNEL and Golgi-staining was used to detect neural cell apoptosis and the density of dendritic spines in the mouse hippocampus. Results: Mice treated with LPS exhibited mitochondrial dysfunction, oxidative stress, an inflammatory response, neural cell apoptosis, and loss of dendritic spines in the hippocampus, leading to impaired hippocampus-related learning and memory performance in the MWM and contextual fear conditioning test. Treatment with elamipretide significantly ameliorated LPS-induced learning and memory impairment during behavioral tests. Notably, elamipretide not only provided protective effects against mitochondrial dysfunction and oxidative stress but also facilitated the regulation of brain-derived neurotrophic factor (BDNF) signaling, including the reversal of important synaptic-signaling proteins and increased synaptic structural complexity. Conclusion: These findings indicate that LPS-induced memory impairment can be attenuated by the mitochondrion-targeted antioxidant elamipretide. Consequently, elamipretide may have a therapeutic potential in preventing damage from the oxidative stress and neuroinflammation that contribute to perioperative neurocognitive disorders (PND), which makes mitochondria a potential target for treatment strategies for PND.

This essay aims to make investigation on the mechanism of glucose metabolism disorder and Lipopolysaccharide administration-induced cognitive function impairment in adult rats with surgery. Divide the objects, 40 male Sprague-Dawley rats at the age of 9 months, into 4 groups. Provide unilateral nephrectomy surgery and/or lipopolysaccharide intraperitoneal injection. Postoperative cognitive function evaluation would be tested by the Morris water maze. Rats with Postoperative Cognitive Dysfunction (POCD) were scanned to analyze the brain glucose metabolism by means of 18F-FDG PET/CT. Phosphatidylinositol 3-Kinase (PI3K), Protein Kinase β (AKT), Insulin Substrates Receptor-2 (IRS-2) and Glucose Transporter 4 (GLUT4) were detected as well. Data will be captured through gene expression in POCD rats via Quantitative Real-Time PCR (QRT-PCR). On the other side, Western Blot was used to measure the expression levels of IRS-2, p-IRS-2, p-PI3K, PI3K, p-AKT, AKT, GLUT4, and p-GLUT4. During the Morris water maze test, the staging time (latency) of rats in each group was becoming short gradually as the training progressed. The incubation time of Day 5 of each group was shorter than that of Day 1 (P < 0.05). On the Day 3 after the surgery, the average target quadrant residence time of Group S+L (100 μg/Kg) was shorter, compared with Group C, L and S. Of which, the average number of perforation was reduced greater than that of Group C (P < 0.05). The average swimming speed of the groups is of no distinct difference (P > 0.05). After the operation, there was no great difference shown among the subjects (P > 0.05) in the average residence time of the target quadrant, the mean number of passages, and the mean swimming speed. On Day 3, the average latency of Group S+L (100 μg/Kg) was longer than Group C (P < 0.05) in the working memory test after the operation. The average latency of rats in Group L and S was showed longer than that in Group C, with tiny difference (P > 0.05). In the 7-Day working memory test, the average latency of the rats in Group L, S and S+L (100 μg/Kg) was obviously longer than that in Group C. Comparing to preoperative rats, POCD rats of Group S+L (100 μg/Kg) were scanned by 18F-FDG PET/CT three days later after the operation. Its SUVmax of the frontal and temporal lobe areas were decreased significantly (P < 0.05). However, difference degree was not significantly shown in the SUVmax between Group C and the preoperative rats (P > 0.05). In comparison with the gene expression of of Group C, the PI3K, IRS-2, AKT and GLUT4 mRNA genes are the key genes in the insulin signaling pathways of the hippocampus of the POCD rats. The expression level was reduced. The expression level of all protein of PI3K, IRS-2, GLUT4 and AKT in the POCD rats was of no great contrast with that in Group C. But for IRS-2 protein, the phosphorylation level has increased, and meanwhile decreased for AKT, PI3K and GLUT4 proteins (P < 0.05). Adult SD rats cognitive dysfunction model treated with unilateral nephrectomy combined and 100 μg/kg LPS intraperitoneal injection were led to abnormal both brain glucose metabolism and insulin expression. The proved phenomenal results signal pathway-related proteins PI3K, IRS-2, AKT and GLUT4. It reached the conclusion that surgical trauma, rather than anesthesia, leads to impaired cognitive function. PI3K, IRS-2, AKT, and GLUT4pathway of brain can be partial explanations of the pathogenesis of POCD.

The brain and lungs represent two of the most vital organs in the human body. The conceptualization of the lung-brain axis has advanced our understanding of the bidirectional communication between the respiratory and central nervous systems. Accumulating evidence indicates that pulmonary diseases, including chronic obstructive pulmonary disease, asthma, acute respiratory distress syndrome and infections such as bacterial pneumonia, influenza and Coronavirus Disease 2019, along with airborne environmental exposures, constitute significant risk factors for various neurological disorders. The lung-brain axis is primarily mediated by microbial, immune, neural, metabolic and hormonal pathways. These mechanisms contribute to the disruption of blood-brain barrier integrity, the activation of neuroglial cells and the dysfunction of the cerebrovascular system, ultimately causing neuronal injury and diverse neurological conditions. Environmental factors, notably airborne particulate matter and chemical pollutants, further amplify the crosstalk among these mechanisms, extending the neurological risk. Here, we summarize the current knowledge regarding the association between pulmonary dysfunction and the development and progression of neurodegenerative diseases (such as Alzheimer’s disease and Parkinson’s disease), stroke, anxiety/depression, epilepsy, and migraine. Additionally, potential therapeutic strategies targeting the lung–brain axis are discussed to foster further research in this emerging field. Elucidating the complex interactions within the lung–brain axis will not only deepen our understanding of the shared pathophysiological mechanisms but also open novel avenues for the early diagnosis, prevention, and treatment of related neurological diseases.

Depression is a neuro-psychiatric disorder that seriously impairs human physical and mental health. Its clinical treatment effect is not satisfactory and the pathogenesis is unclear. Therefore, it is urgent to clarify its pathological mechanism to provide a new direction for the treatment of depression. The "pathological triad", comprising oxidative stress (an imbalance between reactive oxygen species and antioxidant defenses), neuroinflammation (inflammatory responses within the central nervous system), and apoptosis (programmed cell death), has emerged as a central mechanistic driver underlying the pathophysiology of depression. The present study found that chronic unpredictable mild stress (CUMS) drives a significant down-regulation of the synaptojanin-2-binding protein (SYNJ2BP) expression in hippocampal CA1 subregion. Overexpression of SYNJ2BP mitigates oxidative stress, neuroinflammation, neuronal apoptosis and synaptic structural impairment, while concurrently ameliorating depressive- and anxiety-like phenotypes by interacting with SYNJ2 to modulate phosphatidylinositol 4,5-bisphosphate (PIP₂)/inositol 1,4,5-trisphosphate (IP₃) metabolism, and subsequently suppress downstream p38/JNK signaling cascades. Conversely, SYNJ2BP knockdown or exogenous PIP₂ administration abrogates these protective effects, whereas inhibition of IP₃ signaling recapitulates the beneficial outcomes of SYNJ2BP overexpression. Collectively, our findings reveal a new SYNJ2BP/SYNJ2/PIP₂/IP₃ signaling axis in neurons of hippocampal CA1 subregion that critically mediates CUMS-induced neuronal damage and emotional behavioral deficits, thereby potentially providing therapeutic targets for depression treatment.

Postoperative cognitive dysfunction (POCD) is a clinical syndrome characterizing by cognitive impairments in the elderly after surgery. There is limited effective treatment available or clear pathological mechanisms known for this syndrome. In this study, a Connectivity Map (CMap) bioinformatics model of POCD was established by using differently expressed landmark genes in the serum samples of POCD and non-POCD patients from the only human transcriptome study. The predictability and reliability of this model were further supported by the positive CMap scores of known POCD inducers and the negative CMap scores of anti-POCD drug candidates. Most retinoic acid receptor (RAR) agonists were negatively associated with POCD in this CMap model, suggesting that RAR might be a novel target for POCD. Most importantly, acitretin, a clinically used RAR agonist, significantly inhibited surgery-induced cognitive impairments and prevented the reduction in RARα and RARα-target genes in the hippocampal regions of aged mice. The study denotes a reliable CMap bioinformatics model of POCD for future use and establishes that RAR is a novel therapeutic target for treating this clinical syndrome.