Inhibition of TANK-binding kinase1 attenuates the astrocyte-mediated neuroinflammatory response through YAP signaling after spinal cord injury.

AIMS: TANK-binding kinase 1 (TBK1) is involved in regulating the pathological process of a variety of inflammatory diseases in the central nervous system. However, its role and underlying molecular mechanisms in spinal cord injury (SCI) remain largely unknown. METHODS: We employed the TBK1 inhibitor amlexanox (ALX) to address this question. An in vivo clip-compressive SCI model and in vitro lipopolysaccharide (LPS)-induced astrocyte inflammation model were established to examine the effects of TBK1 inhibition on the expression of proinflammatory cytokines. RESULTS: In this study, we found that TBK1 and TBK1-medicated innate immune pathways, such as TBK1/IRF3 and noncanonical NF-κB signaling, were activated in astrocytes and neurons after SCI. Furthermore, inhibition of TBK1 by ALX alleviated neuroinflammation response, reduced the loss of motor neurons, and improved the functional recovery after SCI. Mechanistically, inhibition of TBK1 activity promoted the activation of the noncanonical NF-κB signaling pathway and inhibited p-IRF3 activity in LPS-induced astrocytes, and the TBK1 activity was required for astrocytic activation through yes-associated protein (YAP) signaling after SCI and in LPS-induced astrocytes inflammation model. CONCLUSION: TBK1-medicated innate immune pathway in astrocytes through YAP signaling plays an important role in the pathogenesis of SCI and inhibition of TBK1 may be a potential therapeutic drug for SCI.

Development and validation of a nomogram to predict the risk of surgical site infection within 1 month after transforaminal lumbar interbody fusion.

OBJECTIVE: Surgical site infection (SSI), a common serious complication within 1 month after transforaminal lumbar interbody fusion (TLIF), usually leads to poor prognosis and even death. The objective of this study is to investigate the factors related to SSI within 1 month after TLIF. We have developed a dynamic nomogram to change treatment or prevent infection based on accurate predictions. MATERIALS AND METHODS: We retrospectively analyzed 383 patients who received TLIF at our institution from January 1, 2019, to June 30, 2022. The outcome variable in the current study was the occurrence of SSI within 1 month after surgery. Univariate logistic regression analysis was first performed to assess risk factors for SSI within 1 month after surgery, followed by inclusion of significant variables at P < 0.05 in multivariate logistic regression analysis. The independent risk variables were subsequently utilized to build a nomogram model. The consistency index (C-index), calibration curve and receiver operating characteristic curve were used to evaluate the performance of the model. And the decision curve analysis (DCA) was used to analyze the clinical value of the nomogram. RESULTS: The multivariate logistic regression models further screened for three independent influences on the occurrence of SSI after TLIF, including lumbar paraspinal (multifidus and erector spinae) muscles (LPM) fat infiltration, diabetes and surgery duration. Based on the three independent factors, a nomogram prediction model was built. The area under the curve for the nomogram including these predictors was 0.929 in both the training and validation samples. Both the training and validation samples had high levels of agreement on the calibration curves, and the nomograms C-index was 0.929 and 0.955, respectively. DCA showed that if the threshold probability was less than 0.74, it was beneficial to use this nomograph to predict the risk of SSI after TLIF. In addition, the nomogram was converted to a web-based calculator that provides a graphical representation of the probability of SSI occurring within 1 month after TLIF. CONCLUSION: A nomogram including LPM fat infiltration, surgery duration and diabetes is a promising model for predicting the risk of SSI within 1 month after TLIF. This nomogram assists clinicians in stratifying patients, hence boosting decision-making based on evidence and personalizing the best appropriate treatment.

Yes-associated protein regulates glutamate homeostasis through promoting the expression of excitatory amino acid transporter-2 in astrocytes via ß-catenin signaling.

The homeostasis of glutamate is mainly regulated by the excitatory amino acid transporters (EAATs), especially by EAAT2 in astrocytes. Excessive glutamate in the synaptic cleft caused by dysfunction or dysregulation of EAAT2 can lead to excitotoxicity, neuronal death and cognitive dysfunction. However, it remains unclear about the detailed regulation mechanism of expression and function of astrocytic EAAT2. In this study, first, we found increased neuronal death and impairment of cognitive function in YAPGFAP -CKO mice (conditionally knock out Yes-associated protein [YAP] in astrocytes), and identified EAAT2 as a downstream target of YAP through RNA sequencing. Second, the expression of EAAT2 was decreased in cultured YAP-/- astrocytes and the hippocampus of YAPGFAP -CKO mice, and glutamate uptake was reduced in YAP-/- astrocytes, but increased in YAP-upregulated astrocytes. Third, further investigation of the mechanism showed that the mRNA and protein levels of ß-catenin were decreased in YAP-/- astrocytes and increased in YAP-upregulated astrocytes. Wnt3a activated YAP signaling and up-regulated EAAT2 through ß-catenin. Furthermore, over-expression or activation of ß-catenin partially restored the downregulation of EAAT2, the impairment of glutamate uptake, neuronal death and cognitive decline that caused by YAP deletion. Finally, activation of EAAT2 also rescued neuronal death and cognitive decline in YAPGFAP -CKO mice. Taken together, our study identifies an unrecognized role of YAP signaling in the regulation of glutamate homeostasis through the ß-catenin/EAAT2 pathway in astrocytes, which may provide novel insights into the pathogenesis of brain diseases that closely related to the dysfunction or dysregulation of EAAT2, and promote the development of clinical strategy.

Microglia-Specific Expression of HEXA and HEXB Leads to Poor Prognosis in Glioblastoma Patients.

Glioblastoma multiforme (GBM) is one of the deadliest cancers in brain. There have been few treatment advances for GBM despite increasing scientific understanding of this disease. ß-hexosaminidase (Hex) is an important enzyme system in human body, encoded by two genes, HEXA and HEXB, are closely related to central nervous system (CNS) diseases such as Sandhoff disease (SD) and Tay-Sachs disease (TSD). However, the expression pattern and function of HEXA and HEXB in GBM remains unclear. Here, we found that both the mRNA and protein expression levels of HEXA and HEXB were significantly upregulated in GBM patient samples. The results from single-cell RNA-sequencing (scRNA-seq) database and double immunostaining showed that HEXA and HEXB were specifically expressed in microglia in GBM patient samples. Furthermore, our in vitro experiments revealed that conditioned media from HEXA and HEXB knockdown-microglia cells could inhibit the proliferation and migration of GBM cells. Finally, according to survival analysis based on online database, higher expression of HEXA and HEXB was associated with poor prognosis in GBM patients. In conclusion, these results suggest that microglial HEXA and HEXB play fundamental role in GBM progression, and they will be potential biomarkers for GBM.