Takinib inhibits microglial M1 polarization and oxidative damage after subarachnoid hemorrhage by targeting TAK1-dependent NLRP3 inflammasome signaling pathway

Transforming Growth Factor β1 Protects Against Ischemic Demyelination via Regulating Microglial Lipid Metabolism Pathway

BACKGROUND

Chronic cerebral hypoperfusion-induced white matter lesions are an important cause of vascular cognitive impairment in aging life. TGF-β1 (transforming growth factor β1) is widely recognized as a multifunctional cytokine participating in numerous pathophysiological processes in the central nervous system. In this study, we aimed to evaluate the neuroprotective potentials of TGF-β1 in ischemic white matter lesions.

METHODS

A mouse model of bilateral common carotid artery stenosis was established to imitate the ischemic white matter lesions. The agonist of the TGF-β1 pathway was continuously applied via intraperitoneal injection. The Morris water maze test and gait analysis system were used to assess the cognitive and gait disorders in modeling mice. The Luxol fast blue staining, immunofluorescence, and electron microscopy were conducted to determine the severity of demyelinating lesions, microglial activation, and dysfunction of the autophagy-lysosomal pathway in microglia. Furthermore, primary cultured microglia were exposed to extracted myelin debris and TGF-β1 in vitro to explore the underlying mechanisms.

RESULTS

As evaluated by behavioral tests, TGF-β1 significantly alleviated the cognitive dysfunction and gait disorder in bilateral common carotid artery stenosis-modeling mice. The demyelinating lesion and remyelination process were also found to be highly improved by activation of the TGF-β1 pathway. The results of immunostaining and electron microscopy showed that TGF-β1 could ameliorate microglial activation and the dysfunction of lipid metabolism in myelin-engulfed microglia. Mechanistically, in primary cultured microglia exposed to myelin debris, administration of TGF-β1 notably mitigated the inflammatory response and accumulation of intracellular lipid droplets via promoting the lipid droplets degradation in the autophagy-lysosomal pathway, as quantified by flow cytometry, immunostaining, Western blot, etc. Yet, the application of autophagy inhibitor 3-methyladenine significantly reversed the above anti-inflammatory effects of TGF-β1.

CONCLUSIONS

TGF-β1 relieved cognitive deficit, demyelinating lesions, and microglia-mediated neuroinflammation in bilateral common carotid artery stenosis modeling by reducing abnormal lipid droplet accumulation and dysfunction of the autophagy-lysosomal pathway in microglia. Clinically, staged activation of the TGF-β1 pathway may become a potential target and promising treatment for ischemic white matter lesions and vascular cognitive impairment.

Taraxasterol mediated autophagy inhibition in pancreatic encephalopathy involves its regulation on L1 cell adhesion molecule

Pancreatic encephalopathy (PE) is a frequent complication of acute pancreatitis. This study explored the mechanism of taraxasterol (TAS) in PE treatment by inhibiting pyroptosis via L1 cell adhesion molecule (L1CAM) up-regulation. PE rat models were established and treated with TAS, NLRP3 activator, and sh-L1CAM lentivirus. Serum amylase and lipase activities and Serum, hippocampus, and amygdala IL-18 and IL-1β levels were determined by ELISA, followed by TUNEL and HE staining. Rat nerve injury was evaluated by modified Neurological Severity Score (mNSS). Spontaneous behaviors, learning, memory, and emotions in rats were separately assessed by open field, new object recognition, tail suspension, and forced swimming tests. Microstructures of hippocampal CA1 region and amygdala were observed. NLRP3 + GSDMD + cells, pyroptosis markers, L1CAM, and myelin basic protein (MBP) were detected. PE rat model displayed elevated serum amylase and lipase activities and IL-18 and IL-1β levels, increased mNSS, shortened moving distance, reduced discrimination rate, prolonged immobility time, pathological damage in hippocampal CA1 region and amygdala, increased TUNEL-positive and NLRP3 + GSDMD + cells, raised NLRP3, cleaved caspase-1, GSDMD-N, IL-1β and IL-18 levels, and reduced L1CAM and MBP levels. TAS mitigated behavioral deficits and brain injury and curbed NLRP3-mediated pyroptosis in hippocampal CA1 region and amygdala in PE rats. NLRP3 activation partly averted the beneficial impacts of TAS on PE rats. TAS suppressed nerve cell pyroptosis and facilitated myelin regeneration by up-regulating L1CAM. L1CAM silencing partially abrogated TAS's effect on behavioral deficits and brain injury in PE rats. TAS treated PE by inhibiting pyroptosis via L1CAM up-regulation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10616-025-00721-x.

TAK1 at the crossroads of multiple regulated cell death pathways: from molecular mechanisms to human diseases

Regulated cell death (RCD), the form of cell death that can be genetically controlled by multiple signaling pathways, plays an important role in organogenesis, tissue remodeling, and maintenance of organism homeostasis and is closely associated with various human diseases. Transforming growth factor‐beta‐activated kinase 1 (TAK1) is a member of the serine/threonine protein kinase family, which can respond to different internal and external stimuli and participate in inflammatory and immune responses. Emerging evidence suggests that TAK1 is an important regulator at the crossroad of multiple RCD pathways, including apoptosis, necroptosis, pyroptosis, and PANoptosis. The regulation of TAK1 affects disease progression through multiple signaling pathways, and therapeutic strategies targeting TAK1 have been proposed for inflammatory diseases, central nervous system diseases, and cancers. In this review, we provide an overview of the downstream signaling pathways regulated by TAK1 and its binding proteins. Their critical regulatory roles in different forms of cell death are also summarized. In addition, we discuss the potential of targeting TAK1 in the treatment of human diseases, with a specific focus on neurological disorders and cancer.

Single-cell transcriptomic landscape reveals the role of intermediate monocytes in aneurysmal subarachnoid hemorrhage

Objective

Neuroinflammation is associated with brain injury and poor outcomes after aneurysmal subarachnoid hemorrhage (SAH). In this study, we performed single-cell RNA sequencing (scRNA-seq) to analyze monocytes and explore the mechanisms of neuroinflammation after SAH.

Methods

We recruited two male patients with SAH and collected paired cerebrospinal fluid (CSF) and peripheral blood (PB) samples from each patient. Mononuclear cells from the CSF and PB samples were sequenced using 10x Genomics scRNA-seq. Additionally, scRNA-seq data for CSF from eight healthy individuals were obtained from the Gene Expression Omnibus database, serving as healthy controls (HC). We employed various R packages to comprehensively study the heterogeneity of transcriptome and phenotype of monocytes, including monocyte subset identification, function pathways, development and differentiation, and communication interaction.

Results

(1) A total of 17,242 cells were obtained in this study, including 7,224 cells from CSF and 10,018 cells from PB, mainly identified as monocytes, T cells, B cells, and NK cells. (2) Monocytes were divided into three subsets based on the expression of CD14 and CD16: classical monocytes (CM), intermediate monocytes (IM), and nonclassical monocytes (NCM). Differentially expressed gene modules regulated the differentiation and biological function in monocyte subsets. (3) Compared with healthy controls, both the toll-like receptor (TLR) and nod-like receptor (NLR) pathways were significantly activated and upregulated in IM from CSF after SAH. The biological processes related to neuroinflammation, such as leukocyte migration and immune response regulation, were also enriched in IM. These findings revealed that IM may play a key role in neuroinflammation by mediating the TLR and NLR pathways after SAH.

Interpretation

In conclusion, we establish a single-cell transcriptomic landscape of immune cells and uncover the heterogeneity of monocyte subsets in SAH. These findings offer new insights into the underlying mechanisms of neuroinflammation and therapeutic targets for SAH.

Role of NLRP3 inflammasome in central nervous system diseases

The central nervous system (CNS) is the most delicate system in human body, with the most complex structure and function. It is vulnerable to trauma, infection, neurodegeneration and autoimmune diseases, and activates the immune system. An appropriate inflammatory response contributes to defence against invading microbes, whereas an excessive inflammatory response can aggravate tissue damage. The NLRP3 inflammasome was the first one studied in the brain. Once primed and activated, it completes the assembly of inflammasome (sensor NLRP3, adaptor ASC, and effector caspase-1), leading to caspase-1 activation and increased release of downstream inflammatory cytokines, as well as to pyroptosis. Cumulative studies have confirmed that NLRP3 plays an important role in regulating innate immunity and autoimmune diseases, and its inhibitors have shown good efficacy in animal models of various inflammatory diseases. In this review, we will briefly discuss the biological characteristics of NLRP3 inflammasome, summarize the recent advances and clinical impact of the NLRP3 inflammasome in infectious, inflammatory, immune, degenerative, genetic, and vascular diseases of CNS, and discuss the potential and challenges of NLRP3 as a therapeutic target for CNS diseases.

FGF21 attenuates neuroinflammation following subarachnoid hemorrhage through promoting mitophagy and inhibiting the cGAS-STING pathway

BACKGROUND

Subarachnoid hemorrhage (SAH) represents a form of cerebrovascular event characterized by a notable mortality and morbidity rate. Fibroblast growth factor 21 (FGF21), a versatile hormone predominantly synthesized by the hepatic tissue, has emerged as a promising neuroprotective agent. Nevertheless, the precise impacts and underlying mechanisms of FGF21 in the context of SAH remain enigmatic.

METHODS

To elucidate the role of FGF21 in inhibiting the microglial cGAS-STING pathway and providing protection against SAH-induced cerebral injury, a series of cellular and molecular techniques, including western blot analysis, real-time polymerase chain reaction, immunohistochemistry, RNA sequencing, and behavioral assays, were employed.

RESULTS

Administration of recombinant fibroblast growth factor 21 (rFGF21) effectively mitigated neural apoptosis, improved cerebral edema, and attenuated neurological impairments post-SAH. Transcriptomic analysis revealed that SAH triggered the upregulation of numerous genes linked to innate immunity, particularly those involved in the type I interferon (IFN-I) pathway and microglial function, which were notably suppressed upon adjunctive rFGF21 treatment. Mechanistically, rFGF21 intervention facilitated mitophagy in an AMP-activated protein kinase (AMPK)-dependent manner, thereby preventing mitochondrial DNA (mtDNA) release into the cytoplasm and dampening the activation of the DNA-sensing cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling pathway. Conditional knockout of STING in microglia markedly ameliorated the inflammatory response and mitigated secondary brain injuries post-SAH.

CONCLUSION

Our results present the initial evidence that FGF21 confers a protective effect against neuroinflammation-associated brain damage subsequent to SAH. Mechanistically, we have elucidated a novel pathway by which FGF21 exerts this neuroprotection through inhibition of the cGAS-STING signaling cascade.

TAK1 inhibition mitigates intracerebral hemorrhage-induced brain injury through reduction of oxidative stress and neuronal pyroptosis via the NRF2 signaling pathway

Introduction

Intracerebral hemorrhage (ICH) often triggers oxidative stress through reactive oxygen species (ROS). Transforming growth factor-β-activated kinase 1 (TAK1) plays a pivotal role in regulating oxidative stress and inflammation across various diseases. 5Z-7-Oxozeaenol (OZ), a specific inhibitor of TAK1, has exhibited therapeutic effects in various conditions. However, the impact of OZ following ICH and its underlying molecular mechanisms remain elusive. This study aimed to explore the possible role of OZ in ICH and its underlying mechanisms by inhibiting oxidative stress-mediated pyroptosis.

Methods

Adult male Sprague-Dawley rats were subjected to an ICH model, followed by treatment with OZ. Neurobehavioral function, blood-brain barrier integrity, neuronal pyroptosis, and oxidative stress markers were assessed using various techniques including behavioral tests, immunofluorescence staining, western blotting, transmission electron microscopy, and biochemical assays.

Results

Our study revealed that OZ administration significantly inhibited phosphorylated TAK1 expression post-ICH. Furthermore, TAK1 blockade by OZ attenuated blood-brain barrier (BBB) disruption, neuroinflammation, and oxidative damage while enhancing neurobehavioral function. Mechanistically, OZ administration markedly reduced ROS production and oxidative stress by facilitating nuclear factor-erythroid 2-related factor 2 (NRF2) nuclear translocation. This was accompanied by a subsequent suppression of the NOD-like receptor protein 3 (NLRP3) activation-mediated inflammatory cascade and neuronal pyroptosis.

Discussion

Our findings highlight that OZ alleviates brain injury and oxidative stress-mediated pyroptosis via the NRF2 pathway. Inhibition of TAK1 emerges as a promising approach for managing ICH.

Ferroptosis in early brain injury after subarachnoid hemorrhage: review of literature

Spontaneous subarachnoid hemorrhage (SAH), mainly caused by ruptured intracranial aneurysms, is a serious acute cerebrovascular disease. Early brain injury (EBI) is all brain injury occurring within 72 h after SAH, mainly including increased intracranial pressure, decreased cerebral blood flow, disruption of the blood-brain barrier, brain edema, oxidative stress, and neuroinflammation. It activates cell death pathways, leading to neuronal and glial cell death, and is significantly associated with poor prognosis. Ferroptosis is characterized by iron-dependent accumulation of lipid peroxides and is involved in the process of neuron and glial cell death in early brain injury. This paper reviews the research progress of ferroptosis in early brain injury after subarachnoid hemorrhage and provides new ideas for future research.