miRNA-124-3p targeting of LPIN1 attenuates inflammation and apoptosis in aged male rats cardiopulmonary bypass model of perioperative neurocognitive disorders

Suppression of mPFC-Amygdala Circuit Mitigates Sevoflurane-Induced Cognitive Deficits in Aged Mice

BACKGROUND

Perioperative neurocognitive disorders (PND) are common and costly complications in elderly surgical patients, yet the involvement of specific neural circuits in their etiology remains poorly understood. We hypothesized that neural projections from the medial prefrontal cortex (mPFC) to the amygdala contribute to PND pathogenesis.

METHODS

Using chemogenetic approaches, we selectively suppressed or excited the mPFC and its projections to the amygdala in a murine model exposed to sevoflurane. We assessed cognitive deficits, synaptic plasticity (AMPA receptor activity, long-term potentiation [LTP]), mitochondrial stress, neuroinflammatory markers, and neuronal apoptosis in the amygdala. Additional interventions included pharmacological suppression of AMPA receptors, glutamate biosynthesis, and mitochondrial stress within the amygdala.

RESULTS

Sevoflurane exposure activated the mPFC-amygdala circuit. Chemogenetic suppression of the mPFC attenuated sevoflurane-induced cognitive deficits, AMPA receptor hyperexcitation, mitochondrial dysfunction, neuroinflammation, and neuronal apoptosis in the amygdala. Retrograde inhibition of mPFC projections to the amygdala alleviated cognitive impairments, whereas retrograde excitation exacerbated them. Suppressing AMPA receptors, glutamate synthesis, or mitochondrial stress in the amygdala similarly reduced cognitive deficits and pathological alterations. Notably, mPFC suppression rescued sevoflurane-induced LTP impairment in the amygdala.

CONCLUSIONS

These findings demonstrate that sevoflurane activates the mPFC-amygdala circuit, driving PND-associated cognitive deficits and neuropathological changes. Targeting this circuit or downstream mechanisms (AMPA signaling, mitochondrial stress) may mitigate sevoflurane-induced PND. This study provides empirical evidence implicating specific neural circuitry in anesthetic-related neurocognitive dysfunction.

Dexmedetomidine-mediated improvement of perioperative neurocognitive disorders by miR-184-3p-mediated NLRP3

BACKGROUND

Perioperative neurocognitive disorders (PND) is a neurological complication in the perioperative period, which may lead to severe poor prognosis. Dexmedetomidine (Dex) is a commonly used sedative in the perioperative period. However, the effect of intraoperative anesthetic Dex on PND remains complicated and confusing.

METHODS

PND model was established using aged male mice, treated with Dex, and subjected to behavioral tests. The effect of Dex on pyroptosis was assessed by western blot, enzyme-linked immunosorbent assay and immunofluorescence. In addition, the miRNA expression profile of PND mice was identified by small RNA sequencing and performed PCR to detect miRNAs. Finally, the effect of miRNA on mice neuron pyroptosis was verified in vitro.

RESULTS

We found postoperative cognitive was declined in PND mice compared with control group, while preoperative injection of Dex improved short-term working memory and anxious exploration behavior, alleviated the cognitive impairment. Intriguingly, Dex ameliorated hippocampal inflammation and neuron pyroptosis in PND mice as evidenced by the reduced GSDMD, NLRP3, IL-1β and IL-18. The miRNA expression profile of PND mice hippocampus was disordered, including 5 miRNAs up-regulated and 17 miRNAs down-regulated, compared to the sham group. Dysregulated miRNAs were mainly enriched in biological functions related to neuronal development and signaling pathways related to pyroptosis. MiR-184-3p was the key miRNA, overexpression of miR-184-3p blocked the inhibitory effect of Dex on neuron pyroptosis, which was manifested as increased expression of GSDMD and NLRP3, increased inflammatory factors IL-1β and IL-18.

CONCLUSIONS

This study revealed that miR-184-3p may mediate NLRP3 to prevent the alleviating effect of Dex on PND, which provides a new potential way to improve the therapeutic intervention of PND.

Ginsenoside Rg1 protects the blood-brain barrier and myelin sheath to prevent postoperative cognitive dysfunction in aged mice

In this study, the postoperative cognitive dysfunction (POCD) mouse model was established to observe the changes in inflammation, blood-brain barrier permeability, and myelin sheath, and we explore the effect of ginsenoside Rg1 pretreatment on improving POCD syndrome. The POCD model of 15- to 18-month-old mice was carried out with internal fixation of tibial fractures under isoflurane anesthesia. Pretreatment was performed by continuous intraperitoneal injection of ginsenoside Rg1(40 mg/kg/day) for 14 days before surgery. The cognitive function was detected by the Morris water maze. The contents of interleukin-1β and tumor necrosis factor-α in the hippocampus, cortex, and serum were detected by ELISA. The permeability of blood-brain barrier was observed by Evans blue. The mRNA levels and protein expression levels of 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase), myelin basic protein (MBP), beta-catenin, and cyclin D1 in the hippocampus were analyzed by quantitative PCR and western blotting. The protein expression levels of ZO-1 and Wnt1 in the hippocampus were analyzed by western blotting. Finally, the localizations of CNPase and MBP in the hippocampus were detected by immunofluorescence. Ginsenoside Rg1 can prevent POCD, peripheral and central inflammation, and blood-brain barrier leakage, and reverse the downregulation of ZO-1, CNPase, MBP, and Wnt pathway-related molecules in aged mice. Preclinical studies suggest that ginsenoside Rg1 improves postoperative cognitive function in aged mice by protecting the blood-brain barrier and myelin sheath, and its specific mechanism may be related to the Wnt/β-catenin pathway.

Effects of nicotine on microRNA-124 expression in bile duct ligation-induced liver fibrosis in rats

BACKGROUND

Nicotine, the main compound of smoking may exert its effects by changing the expression of microRNAs (miRNAs). This study was conducted to further investigate the molecular mechanisms of miRNA-dependent effects of nicotine in an animal model of liver fibrosis.

METHODS

The bile duct ligation (BDL) approach was used to create a model of liver fibrosis. Twenty-four male Wistar rats were used in the study. The effects of nicotine administration on miRNA-124 expression, as well as alpha-smooth muscle actin (liver fibrosis marker) and chemokine ligand 2 (an inflammatory chemokine), were investigated using RT-qPCR. In addition, the mRNA and protein expression of signal transducer and activator of transcription 3 (STAT-3; as a potential target for miRNA-124) were investigated by RT-qPCR and immunofluorescence, respectively. Liver enzyme activity levels were measured using a colorimetric assay. In addition, the effects of nicotine on the process of liver fibrosis were investigated with histological studies.

RESULTS

The development of liver fibrosis in BDL rats and nicotine administration led to a decrease in miRNA-124 expression. The decrease in the expression is accompanied by the increase in the expression of fibrotic and proinflammatory genes. Also, an increase in STAT-3 mRNA and protein expression was observed in the fibrotic rats that received nicotine. In addition, the significant increase in bilirubin and liver enzymes in fibrotic rats worsens with nicotine administration. The results of histological studies also confirm these results.

CONCLUSION

Considering that miRNA-124 is an anti-inflammatory miRNA, it can be concluded that the decrease in its expression due to nicotine exposure leads to an increase in inflammatory processes and subsequently to an increase in liver fibrosis.

Epigenetic regulation of inflammation: The metabolomics connection

Epigenetic factors are considered the regulator of complex machinery behind inflammatory disorders and significantly contributed to the expression of inflammation-associated genes. Epigenetic modifications modulate variation in the expression pattern of target genes without affecting the DNA sequence. The current knowledge of epigenetic research focused on their role in the pathogenesis of various inflammatory diseases that causes morbidity and mortality worldwide. Inflammatory diseases are categorized as acute and chronic based on the disease severity and are regulated by the expression pattern of various genes. Hence, understanding the role of epigenetic modifications during inflammation progression will contribute to the disease outcomes and therapeutic approaches. This review also focuses on the metabolomics approach associated with the study of inflammatory disorders. Inflammatory responses and metabolic regulation are highly integrated and various advanced techniques are adopted to study the metabolic signature molecules. Here we discuss several metabolomics approaches used to link inflammatory disorders and epigenetic changes. We proposed that deciphering the mechanism behind the inflammation-metabolism loop may have immense importance in biomarkers research and may act as a principal component in drug discovery as well as therapeutic applications.

The role and regulatory mechanism of HIF-1α in myocardial injury in rats undergoing cardiopulmonary bypass

BACKGROUND

Hypoxia-inducible factor-1alpha (HIF-1α) is a transcription factor implicated in physiological and pathological responses to hypoxia. The present study aims to investigate the effect and mechanism of HIF-1α on cardiopulmonary bypass (CPB)-related myocardial injury, thereby conferring a theoretical basis for the clinical treatment of myocardial injury in CPB.

METHODS

An experimental model of CPB was established in rats by surgery. Adenovirus-packaged overexpression vectors and antiagomiRNA were used to overexpress HIF-1α and NR4A1 or inhibit miR-124-3p expression in rat myocardial tissues, respectively. qRT-PCR and Western blot detected HIF-1α, miR-124-3p, and NR4A1 expression in myocardial tissues. The rat cardiac function was monitored through an echocardiogram. The rat plasma at different stages of CPB was collected, followed by the detection of IL-6, cTnT, CK-MB, and IL-1β. TUNEL staining measured apoptosis in myocardial tissues. ChIP assay analysed the enrichment of HIF-1α on the miR-124-3p promoter. The binding relationships between HIF-1α and miR-124-3p promoter sequence and between miR-124-3p and NR4A1 3'UTR sequence were confirmed by dual-luciferase reporter assay.

RESULTS

HIF-1α expression had no significant change after CPB modelling. Overexpression of HIF-1α improved the cardiac function of CPB rats, decreased plasma IL-6, cTnT, CK-MB, and IL-1β levels, and reduced TUNEL-positive myocardial cells. HIF-1α was enriched on the miR-124-3p promoter and promoted miR-124-3p expression. miR-124-3p bound to NR4A1 3'UTR sequence and targeted NR4A1 expression. Inhibition of miR-124-3p or overexpression of NR4A1 partially reversed the ameliorative effect of HIF-1α overexpression on myocardial injury in CPB rats.

CONCLUSION

Overexpression of HIF-1α can improve myocardial injury in CPB rats via the miR-124-3p/NR4A1 axis.

Research progress of postoperative cognitive dysfunction in cardiac surgery under cardiopulmonary bypass

Cardiopulmonary bypass (CPB) is often used in cardiothoracic surgery because its nonphysiological state causes pathophysiological changes in the body, causing multiorgan and multitissue damage to varying degrees. Postoperative cognitive dysfunction (POCD) is a common central nervous system complication after cardiac surgery. The etiology and mechanism of POCD are not clear. Neuroinflammation, brain mitochondrial dysfunction, cerebral embolism, ischemia, hypoxia, and other factors are related to the pathogenesis of POCD. There is a close relationship between CPB and POCD, as CPB can cause inflammation, hypoxia and reperfusion injury, and microemboli formation, all of which can trigger POCD. POCD increases medical costs, seriously affects patients' quality of life, and increases mortality. Currently, there is a lack of effective treatment methods for POCD. Commonly used methods include preoperative health management, reducing inflammation response during surgery, preventing microemboli formation, and implementing individualized rehabilitation programs after surgery. Strengthening preventive measures can minimize the occurrence of POCD and its adverse effects.

LPIN1 Is a Regulatory Factor Associated With Immune Response and Inflammation in Sepsis

Objectives

Sepsis is a clinical disease that is typically treated in the intensive care unit, and the complex pathophysiology under this disease has not been thoroughly understood. While ferroptosis is involved in inflammation and infection, its effect in sepsis is still unknown. The study aimed to identify ferroptosis-related genes in sepsis, providing translational potential therapeutic targets.

Methods

The dataset GSE65682 was used to download the sample source from the Gene Expression Omnibus (GEO) database. Consensus weighted gene co-expression network analysis (WGCNA) was performed to find suspected modules of sepsis. The differentially expressed genes (DEGs) most significantly associated with mortality were intersected with those altered by lipopolysaccharide (LPS) treatment and were further analyzed for the identification of main pathways of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. The related pathway markers were further verified by qPCR.

Results

A total of 802 blood samples with sepsis were included for WGCNA, which identified 21 modules. Intersected with ferroptosis databases and LPS treatment groups, we identified two ferroptosis-related genes: PEBP1 and LPIN1. Only LPIN1 contributes to a poor outcome. Then, 205 DEGs were further identified according to the high or low LPIN1 expression. Among them, we constructed a gene regulatory network with several transcriptional factors using the NetworkAnalyst online tool and identified that these genes mostly correlate with inflammation and immune response. The immune infiltration analysis showed that lower expression of LPIN1 was related to macrophage infiltration and could be an independent predictor factor of the survival status in sepsis patients. Meanwhile, the multivariate Cox analysis showed that LPIN1 had a significant correlation with survival that was further verified by in vitro and in vivo experiments.

Conclusion

In conclusion, LPIN1 could become a reliable biomarker for patient survival in sepsis, which is associated with immune and inflammation status.

VRT-043198 Ameliorates Surgery-Induced Neurocognitive Disorders by Restoring the NGF and BNDF Expression in Aged Mice

BACKGROUND

Perioperative neurocognitive disorders (PND) are common surgical complications in the elderly. Pyroptosis-associated inflammation has been suggested to participate in a series of neurocognitive diseases, including Alzheimer's disease. Given that VRT-043198 can reportedly inhibit caspase-1-induced pyroptosis, this study sought to determine whether VRT-043198 reduced PND in a mouse model following abdominal exploratory laparotomy.

METHODS

20-month-old male C57/BL mice were used to establish an abdominal exploratory laparotomy (AEL) model of PND. VRT-043198 (1, 10 and 100 mg/kg) was administered intraperitoneally immediately after surgery. Thirty days post-surgery, the mice were evaluated in the Morris water maze test. Their number of neurons, neurotrophin nerve growth factor (NGF) levels and brain-derived neurotrophic factor (BDNF) were measured. In the hippocampus, A1-type astrocytes and M1-type microglia were assessed using an immunofluorescence assay and Western blot, respectively. Caspase-1 activity, IL-1β, IL-18, and PPAR-γ were also measured 24h after surgery.

RESULTS

VRT-043198 administration increased the time to cross the platform and increased the ratio of distance and time in the targeted quadrant after surgery. Furthermore, it was found that VRT-043198 restored neuronal amount, increased NGF and BDNF and decreased the number of A1-type astrocytes and M1-type microglia. VRT-043198 also attenuated caspase-1 activity, downregulated IL-1β and IL-18, but increased PPAR-γ 24h post-surgery.

CONCLUSION

VRT-043198 improved PND in aged mice after abdominal exploratory laparotomy by restoring the NGF and BNDF expression. These results indicate that VRT-043198 may be a potential therapy for PND.