Inhibition of voltage-gated Hv1 alleviates LPS-induced neuroinflammation via regulation of microglial metabolic reprogramming.

A growing body of evidence highlights the crucial role of metabolic reprogramming in activated immune cells, significantly contributing to both the initiation and progression of neuroinflammation and neurodegenerative diseases. The voltage-gated H channel (Hv1) has been reported to be involved in microglial activation and acts as a key driver of neuroinflammation. This study aimed to explore how Hv1-mediated metabolic reprogramming contributes to neuroinflammation and to assess the therapeutic potential of the Hv1 inhibitor 2-GBI in a model of lipopolysaccharide (LPS)-induced neuroinflammation. We investigated the influence of 2-GBI on the generation of ROS, metabolic reprogramming, and pro-inflammatory mediator production in vitro and examined the therapeutic effect of 2-GBI on microglial activation and hippocampal neuroinflammation in vivo. The results indicated that 2-GBI attenuated the LPS-induced pro-inflammatory response and aerobic glycolysis in microglia, specifically mitigating HIF1α-mediated upregulation of glycolysis. 2-GBI exerted a protective effect against LPS-induced neuroinflammation through HIF1α pathway-regulated aerobic glycolysis. Using a transwell coculture system, we demonstrated that 2-GBI reversed PC12 cell death caused by BV2-mediated neuroinflammation. In vivo experiments further suggested that 2-GBI mitigated neuroinflammatory processes and cognitive dysfunction via microglial metabolic reprogramming. Collectively, our results highlight the potential of Hv1 inhibition as a therapeutic strategy for alleviating LPS-induced neuroinflammation by modulating microglial metabolic reprogramming.

Different Sources of Bone Marrow Mesenchymal Stem Cells: A Comparison of Subchondral, Mandibular, and Tibia Bone-derived Mesenchymal Stem Cells.

BACKGROUND: Stem cell properties vary considerably based on the source and tissue site of mesenchymal stem cells (MSCs). The mandibular condyle is a unique kind of craniofacial bone with a special structure and a relatively high remodeling rate. MSCs here may also be unique to address specific physical needs. OBJECTIVE: The aim of this study was to compare the proliferation and multidirectional differentiation potential among MSCs derived from the tibia (TMSCs), mandibular ramus marrow (MMSCs), and condylar subchondral bone (SMSCs) of rats in vitro. METHODS: Cell proliferation and migration were assessed by CCK-8, laser confocal, and cell scratch assays. Histochemical staining and real-time PCR were used to evaluate the multidirectional differentiation potential and DNA methylation and histone deacetylation levels. RESULTS: The proliferation rate and self-renewal capacity of SMSCs were significantly higher than those of MMSCs and TMSCs. Moreover, SMSCs possessed significantly higher mineralization and osteogenic differentiation potential. Dnmt2, Dnmt3b, Hdac6, Hdac7, Hdac9, and Hdac10 may be instrumental in the osteogenesis of SMSCs. In addition, SMSCs are distinct from MMSCs and TMSCs with lower adipogenic differentiation and chondrogenic differentiation potential. The multidirectional differentiation capacities of TMSCs were exactly the opposite of those of SMSCs, and the results of MMSCs were intermediate. CONCLUSION: This research offers a new paradigm in which SMSCs could be a useful source of stem cells for further application in stem cell-based medical therapies due to their strong cell renewal and osteogenic capacity.

Propofol inhibits neuroinflammation and metabolic reprogramming in microglia in vitro and in vivo.

Microglial activation-induced neuroinflammation is closely related to the development of sepsis-associated encephalopathy. Accumulating evidence suggests that changes in the metabolic profile of microglia is crucial for their response to inflammation. Propofol is widely used for sedation in mechanically ventilated patients with sepsis. Here, we investigate the effect of propofol on lipopolysaccharide-induced neuroinflammation, neuronal injuries, microglia metabolic reprogramming as well as the underlying molecular mechanisms. The neuroprotective effects of propofol (80 mg/kg) in vivo were measured in the lipopolysaccharide (2 mg/kg)-induced sepsis in mice through behavioral tests, Western blot analysis and immunofluorescent staining. The anti-inflammatory effects of propofol (50 µM) in microglial cell cultures under lipopolysaccharide (10 ng/ml) challenge were examined with Seahorse XF Glycolysis Stress test, ROS assay, Western blot, and immunofluorescent staining. We showed that propofol treatment reduced microglia activation and neuroinflammation, inhibited neuronal apoptosis and improved lipopolysaccharide-induced cognitive dysfunction. Propofol also attenuated lipopolysaccharide-stimulated increases of inducible nitric oxide synthase, nitric oxide, tumor necrosis factor-α, interlukin-1ß and COX-2 in cultured BV-2 cells. Propofol-treated microglia showed a remarkable suppression of lipopolysaccharide-induced HIF-1α, PFKFB3, HK2 expression and along with downregulation of the ROS/PI3K/Akt/mTOR signaling pathway. Moreover, propofol attenuated the enhancement of mitochondrial respiration and glycolysis induced by lipopolysaccharide. Together, our data suggest that propofol attenuated inflammatory response by inhibiting metabolic reprogramming, at least in part, through downregulation of the ROS/PI3K/Akt/mTOR/HIF-1α signaling pathway.

Isoschaftoside Inhibits Lipopolysaccharide-Induced Inflammation in Microglia through Regulation of HIF-1α-Mediated Metabolic Reprogramming.

Isoschaftoside is a C-glycosyl flavonoid extracted from the root exudates of Desmodium uncinatum and Abrus cantoniensis. Previous studies suggested that C-glycosyl flavonoid has neuroprotective effects with the property of reducing oxidative stress and inflammatory markers. Microglia are key cellular mediators of neuroinflammation in the central nervous system. The aim of this study was to investigate the effect of isoschaftoside on lipopolysaccharide-induced activation of BV-2 microglial cells. The BV-2 cells were exposed to 10 ng/ml lipopolysaccharide and isoschaftoside (0-1000 µM). Isoschaftoside effectively inhibited lipopolysaccharide-induced nitric oxide production and proinflammatory cytokines including iNOS, TNF-α, IL-1ß, and COX2 expression. Isoschaftoside also significantly reduced lipopolysaccharide-induced HIF-1α, HK2, and PFKFB3 protein expression. Induction of HIF-1α accumulation by CoCl2 was inhibited by isoschaftoside, while the HIF-1α specific inhibitor Kc7f2 mitigated the metabolic reprogramming and anti-inflammatory effect of isoschaftoside. Furthermore, isoschaftoside attenuated lipopolysaccharide-induced phosphorylation of ERK1/2 and mTOR. These results suggest that isoschaftoside can suppress inflammatory responses in lipopolysaccharide-activated microglia, and the mechanism was partly due to inhibition of the HIF-1α-mediated metabolic reprogramming pathway.

Cyclin-dependent kinase 5 inhibitor attenuates lipopolysaccharide-induced neuroinflammation through metabolic reprogramming.

The atypical cyclin-dependent kinase 5 (CDK5) is considered a neuron-specific kinase that plays important roles in many cellular functions including neuronal migration, neuronal differentiation, synapse development, and synaptic functions. However, the role of CDK5 in microglia under physiological and pathological conditions remains unclear. This study showed that treatment with lipopolysaccharide (LPS) caused the release of pro-inflammatory mediators and increased expression of CDK5 in BV2 microglia in vitro. Moreover, lipopolysaccharide treatment-induced glycolysis by increasing the expression levels of HIF-1α, PFKFB3, and HK2. Application of CDK5 inhibitor roscovitine significantly decreased LPS-induced CDK5 expression and glycolysis, thus suppressing neuroinflammation in the cells. The roscovitine treatment of BV2 cells also significantly blocked the HIF-1 activator, CoCl2-mediated HIF-1α, HK2, and PFKFB3 expression. Finally, we demonstrated that roscovitine inhibited microglial activation, metabolic reprogramming, expression of pro-inflammatory markers, cell apoptosis, and alleviated memory impairment in LPS-injected mice. In summary, our results suggest that inhibition of CDK5 can reduce the neuroinflammation of microglia through modulation of metabolic reprogramming.

The impact of benzo[a]pyrene on murine allergic airway inflammation via epigenetic remodeling.

Simultaneous exposure to both BaP and house dust mites (HDM) has been shown to exacerbate pulmonary inflammation and hyperresponsiveness in a murine asthma model. The mechanistic insight into epigenetic inheritance for this effect, however, remains to be clarified. As such, in this study, we explore the molecular basis for the enhancement of asthma. Female BAL/C mice were intranasally administered HDM (25 µg in 25 µL saline) and/or BaP (10 µg/kg) every other day for 9 weeks. RNA sequencing and DNA methylation assessment were used to explore the underlying mechanism. Following simultaneous exposure to HDM and BaP, mice exhibited pulmonary inflammation and the transcript level of IL4i1b, muc4 and IL22ra2 that were associated with altered DNA methylation, suggesting that there may be an epigenetic basis for BaP-induced asthma exacerbation. Our data suggest that DNA methylation is a major epigenetic modification that accompanies airway remodeling associated with changes in the allergic mice.

Long-term exposure to phenanthrene at environmental-level induces intestinal dysbiosis and disrupted hepatic lipid metabolism in mice.

Phenanthrene (Phe), among the most ubiquitous polycyclic aromatic hydrocarbons (PAHs) existing in nature and foodstuffs, has severe effects on hepatic lipids metabolism. However, the detailed mechanism involved is still unknown. For environmental chemicals can disturb intestinal microbiota, which plays a vital role in lipids metabolism, we hypothesized that oral exposure to Phe may disrupt the intestinal microbiota, leading to the induction of an abnormal inflammatory response and lipid metabolism dysfunction. Herein, male mice were orally exposed to Phe (0.05, 0.5 and 5 mg/kg/2d) for ten weeks and the results showed that long term exposure to Phe induced significant alteration in relative Bacteroidetes, Firmicutes and Proteobacteria abundance in male mice. Histopathological anomalies, and significantly increased hepatic levels of free fatty acid, cholesterol and triglyceride were observed as well. The expression of hepatic proteins linked to lipid metabolism including peroxisome proliferator-activated receptors (PPARs), liver X receptor ß (LXRß) and retinoid X receptors (RXRs) were upregulated. The importance of the gut microbiota in Phe-altered lipid metabolism disorder was further confirmed by fecal microbiota transplantation (FMT). FMT intervention boosted microbial diversity and attenuated Phe-induced elevation in liver somatic index and hepatic total lipids levels. These results demonstrated that environmental-level Phe altered the composition of gastrointestinal bacteria and subsequently induced hepatic lipid metabolism disorder. These results would be helpful for understanding the health risk posed by Phe.

Diagnostic Value of MRI Lamellated Hyperintense Synovitis in Periprosthetic Infection of Hip.

OBJECTIVE: To investigate the correlation between magnetic resonance imaging (MRI) lamellated hyperintense synovitis and periprosthetic infection of hip arthroplasty and estimate its value in the diagnosis of infection after hip replacement. METHODS: A retrospective analysis of 50 patients who underwent MRI from January 2016 to June 2019 after hip replacement was performed. The MRI scanning was performed with a 1.5T clinical imaging unit using SEMAC protocols. A total of 25 patients (cohort 1) showed infected total hip arthroplasty, and 25 patients had non-infected arthroplasty as controls (cohort 2). Two musculoskeletal radiologists, blinded to the clinical diagnosis, reviewed all the images for the presence of lamellated hyperintense synovitis independently. The cases were rereviewed by each reader after 2 weeks. The sensitivity, specificity, positive predictive value, and negative predictive value were calculated using the first reads. The Kappa statistic was used to assess inter-observer and intra-observer reliability. RESULTS: The incidence of lamellated hyperintense synovitis was 76%-88% in the experimental group and 8%-16% in the control group. The sensitivity of lamellated hyperintense synovitis for infection was 0.80-0.88 (95% confidence interval [CI]:0.59 - 0.97), the specificity was 0.84~0.92 (95% CI: 0.64 -0.99), the positive predictive value 0.83-0.92 (95% CI: 0.67 - 0.98), the negative predictive value 0.81 - 0.88 (95% CI: 0.65 - 0.96). The agreement between two readers was substantial (Kappa = 0.76, 95% CI: 0.58 - 0.94, P < 0.05). There were moderate inter-observer agreements for both readers, reader 1 (Kappa = 0.48, 95%CI: 0.23 - 0.72, P < 0.05) and reader 2 (Kappa = 0.44，95% CI: 0.19 - 0.69, P < 0.05). CONCLUSION: In this cohort, the presence of lamellated hyperintense synovitis in the MRI of hip arthroplasty showed high sensitivity and specificity for infection. This sign had substantial intra-observer reliability and moderate inter-observer reliability in the classification of the synovial pattern.