Targeting MS4A4A: A novel pathway to improve immunotherapy responses in glioblastoma.

INTRODUCTION: Glioblastoma (GBM) remains a challenging brain tumor to treat, with limited response to PD-1 immunotherapy due to tumor-associated macrophages (TAMs), specifically the M2 phenotype. This study explores the potential of MS4A4A (membrane spanning four domains, subfamily A, member 4A) inhibition in driving M2 macrophage polarization toward the M1 phenotype via the ferroptosis pathway to enhance the effectiveness of immunotherapy in GBM. METHODS: Single-cell RNA sequencing and spatial transcriptomic analyses were employed to characterize M2 macrophages and MS4A4A expression in GBM. In vitro studies utilizing TAM cultures, flow cytometry, and western blot validations were conducted to assess the impact of MS4A4A on the tumor immune microenvironment and M2 macrophage polarization. In vivo models, including subcutaneous and orthotopic transplantation in mice, were utilized to evaluate the effects of MS4A4A knockout and combined immune checkpoint blockade (ICB) therapy on tumor growth and response to PD-1 immunotherapy. RESULTS: Distinct subsets of GBM-associated macrophages were identified, with spatial distribution in tumor tissue elucidated. In vivo experiments demonstrated that inhibiting MS4A4A and combining ICB therapy effectively inhibited tumor growth, reshaped the tumor immune microenvironment by reducing M2 TAM infiltration and enhancing CD8+ T-cell infiltration, ultimately leading to complete tumor eradication. CONCLUSION: MS4A4A inhibition shows promise in converting M2 macrophages to M1 phenotype via ferroptosis, decreasing M2-TAM infiltration, and enhancing GBM response to PD-1 immunotherapy. These findings offer a novel approach to developing more effective immunotherapeutic strategies for GBM.

Puerarin ameliorates acute lung injury by modulating NLRP3 inflammasome-induced pyroptosis.

We commenced to analyze putative anti-pyroptosis effects of puerarin (PU) as mediated by the PP2A-HDAC1-NLRP3 pathway in acute lung injury (ALI). ALI animal and cell models were constructed, followed by treatment of PU. Then, the effect of HDAC1, PP2A, and NLRP3 on cell inflammation and pyroptosis was explored. The interaction between HDAC1 and PP2A as well as between PP2A and NLRP3 was analyzed. Our findings suggested that PU downregulated HDAC1 expression to alleviate symptoms of ALI. HDAC1 overexpression promoted inflammation induced by LPS, which reversed the inhibitory effect of PU on ALI. HDAC1 overexpression also decreased PP2A expression, suggesting that PP2A was involved in the effects of HDAC1 on LPS-induced inflammation. PP2A exerted inhibitory effects on NLRP3. Meanwhile, PU hindered the progression of ALI by silencing HDAC1 or overexpressing PP2A both in vivo and in vitro. Taken together, PU restrained pyroptosis of cells induced by NLRP3 inflammasome to abate ALI.

Hepatoprotective effects of sevoflurane against hepatic ischemia-reperfusion injury by regulating microRNA-124-3p-mediated TRAF3/CREB axis.

The purpose of the present study is to define the role of sevoflurane (SEV) in hepatic ischemia-reperfusion (I/R) injury as well as its underlying mechanism. Initially, hepatic I/R animal models and I/R hepatocyte models were established in C57BL/6 mice and normal mouse hepatocytes (BNL CL.2) after SEV preconditioning, respectively, followed by detection of microRNA-124-3p (miR-124-3p), TRAF3, and CREB expression by RT-qPCR and Western blot analysis. In addition, miR-124-3p, TRAF3 and CREB expression in hepatocytes was altered to identify their roles in modulating the levels of glutathione transferase (GST), aspartate aminotransferase (AST) and alanine aminotransferase (ALT), and inflammation-related factors and hepatocyte apoptosis by ELISA and flow cytometry respectively. The effects of SEV on the miR-124-3p/TRAF3/CREB axis were also verified in vitro and in vivo. IP assay was performed to verify the effect of TRAF3 on CREB ubiquitination in BNL CL.2 cells, and the cycloheximide (CHX) intervention experiment to detect the stability of CREB protein. SEV augmented the miR-124-3p expression in I/R animal and cell models. Moreover, SEV was observed to suppress I/R-induced liver damage, GST, ALT, and AST levels, hepatocyte apoptosis and inflammation. Overexpression of miR-124-3p resulted in alleviation of hepatic I/R injury, which was countered by TRAF3 overexpression. miR-124-3p targeted TRAF3, while TRAF3 promoted CREB ubiquitination and reduced protein stability of CREB. SEV could impede I/R-induced liver damage, GST, ALT, and AST levels, hepatocyte apoptosis and inflammation via mediation of the miR-124-3p/TRAF3/CREB axis in vitro and in vivo. Collectively, SEV may upregulate miR-124-3p to inhibit TRAF3 expression, thereby reducing the ubiquitination and degradation of CREB, alleviating hepatic I/R injury.

Dexmedetomidine Ameliorates Postoperative Cognitive Dysfunction via the MicroRNA-381-Mediated EGR1/p53 Axis.

Postoperative cognitive dysfunction (POCD; cognitive change associated with anesthesia and surgery) is one of the most serious long-term postoperative complications that occur in elderly patients. Dexmedetomidine (DEX) has been shown to be beneficial for improving outcomes of postoperative cognitive function. However, the exact mechanism underlying this role requires is yet to be found. The present study aims to determine the pathways involved in the protective effects of DEX against POCD in C57BL/6 J aged mice. DEX was administered after POCD modeling in C57BL/6 J aged mice. The cognitive function was evaluated after DEX treatment using novel object recognition, open field, and Y-maze tests. We also assessed its effects on neuron apoptosis and production of TNF-α and IL-1ß in mouse brain tissues as well as expression levels of DNA damage-related proteins p53, p21, and γH2AX. Interactions between early growth response 1 (EGR1) and p53, microRNA (miR)-381, and EGR1 were identified by ChIP and luciferase reporter assays, and gain- and loss-of-function experiments were performed to confirm the involvement of their interaction in POCD. DEX administration attenuated hippocampal neuron apoptosis, neuroinflammation, DNA damage, and cognitive impairment in aged mice. miR-381 targeted EGR1 and disrupted its interaction with p53, leading to a decline in hippocampal neuron apoptosis, DNA damage, neuroinflammation, and cognitive impairment. Furthermore, DEX administration resulted in the enhancement of miR-381 expression and the subsequent inhibition of EGR1/p53 to protect against cognitive impairment in aged mice. Overall, these results indicate that DEX may have a potential neuroprotective effect against POCD via the miR-381/EGR1/p53 signaling, shedding light on the mechanisms involved in neuroprotection in POCD.

Neuroprotection of the Developing Brain by Dexmedetomidine Is Mediated by Attenuating Single Propofol-induced Hippocampal Apoptosis and Synaptic Plasticity Deficits.

Dexmedetomidine (DEX) has neuroprotective effects and its efficacy was determined in propofol-treated pups. Postnatal day (P) 7 rats were exposed to propofol and DEX to investigate the induced apoptosis-related gene expression. Furthermore, synaptic structural changes at the cellular level were observed by electron microscopy. Induction of hippocampal long-term potentiation (LTP) of P30 rats and long-lasting performance of spatial discrimination at P30 and P60 were evaluated. After a single propofol exposure to P7 rats, DEX pretreatment effectively rescued the profound apoptosis seen in hippocampal neurocytes, and strongly reversed the aberrant expression levels of Bcl2-like 1 (BCL2L1), matrix metallopeptidase 9 (MMP-9) and cleaved caspase 3 (CC3), and sharply enhanced synaptic plasticity. However, there were no significant differences in escape latency or crossing times in a probe test. This was accompanied by no obvious reduction in search strategies among the rat groups. No impairment of long-term learning and memory in P30 or P60 rats was detected when using a single dose propofol treatment during the most vulnerable period of brain development. DEX was shown to ameliorate the rodent developmental neurotoxicity caused by a single neonatal propofol challenge, by altering MMP-9, BCL2L1 and CC3 apoptotic signaling.

Protective effects of bone marrow-derived endothelial progenitor cells and Houttuynia cordata in lipopolysaccharide-induced acute lung injury in rats.

BACKGROUND/AIMS: Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a serious health problem, and an effective treatment is needed for use in the clinical setting. METHODS: In this study, we first constructed ALI models in Adult Sprague-Dawley rats. We then used an herbal medicine, Houttuynia cordata (HC), to enhance the effect of endothelial progenitor cells (EPCs) on ALI. RESULTS: (1) HC improved the therapeutic effects of EPCs on lipopolysachharide-induced ALI in the rat model; (2) HC down-regulated the anti-inflammatory response by suppressing inflammatory cytokines; (3) the combination of EPC and HC reduced expression of iNOS and ET-1 and subsequently prevented lung injury. CONCLUSION: Combined EPC and HC therapy was more effective than either therapy alone. EPC and HC could be used in the clinical treatment of ALI.

Protective effects of penehyclidine hydrochloride on liver injury in a rat cardiopulmonary bypass model.

BACKGROUND AND OBJECTIVE: Hepatic injury after cardiac surgery is considered to be a consequence of cardiopulmonary bypass (CPB). The aim of this study was to test the hypothesis that penehyclidine hydrochloride (PHC) could attenuate hepatic injury using a rat CPB model. METHODS: Male Sprague-Dawley rats were randomly divided into six groups (eight per group), including sham-operated control, sham low-dose PHC control (0.6 mg kg), sham high-dose PHC control (2.0 mg kg), vehicle control, low-dose PHC (0.6 mg kg) and high-dose PHC (2.0 mg kg)-treated groups. Blood samples were collected from the femoral artery at the cessation of CPB and the serum levels of the liver enzymes, including alanine aminotransferase (ALT) and aspartate aminotransferase (AST), were determined. The ultrastructure of liver tissue was also examined under an electron microscope. RESULTS: In the sham-operated groups, high-dose PHC and low-dose PHC had no significant impact on the levels of respiratory rate, heart rate, blood pressure, ECG, ALT or AST. Compared with the sham group, the serum levels of ALT and AST were increased significantly in the surgical groups. PHC alleviated all the biochemical and histopathological changes in a dose-dependent manner. The ALT and AST levels in the high-dose PHC-treated groups were significantly lower than those in the vehicle control group. CONCLUSION: Treatment with penehyclidine hydrochloride could improve liver function during CPB.