Yi-Zhi-Fang-Dai Formula Exerts Neuroprotective Effects Against Pyroptosis and Blood-Brain Barrier-Glymphatic Dysfunctions to Prevent Amyloid-Beta Acute Accumulation After Cerebral Ischemia and Reperfusion in Rats

β-hydroxybutyrate alleviates neurological deficits by restoring glymphatic and inflammation after subarachnoid hemorrhage in mice

BACKGROUND

Both glymphatic system dysfunction and inflammatory response aggravate neurological dysfunction after subarachnoid hemorrhage (SAH). Studies have shown that β-hydroxybutyrate (BHB) may mitigate painful diabetic neuropathy (PDN) by upregulating SNTA1 expression and reinstating AQP4 polarity. However, the potential of BHB to ameliorate glymphatic system function and inflammatory response in SAH mice remains uncertain.

METHODS

The SAH models were constructed by injection of arterial blood into cisterna Magana. Three groups of C57 mice were randomly assigned: Sham, SAH, and BHB. All mice were subjected to neurological function assessment, western blot, immunofluorescence double staining, and RNA-seq. Glymphatic system function was examined with tracer and immunofluorescence double staining, and the differential genes were examined with RNA-seq. In addition, the expression of related inflammation was detected.

RESULTS

Compared with the SAH group, BHB reinstated AQP4 polarization by upregulating SNTA1 protein to enhance the glymphatic system. According to RNA-seq, the different genes were primarily connected to microglia activation, astrocytes, and inflammation. Western blot and immunofluorescence further confirmed that the related inflammatory protein expression levels were upregulated. BHB attenuated neuroinflammation after SAH. Ultimately, it can mitigate the neurological deficits in SAH mice.

CONCLUSION

The study reveals a novel mechanism that BHB treatment mitigates neurologic impairment in SAH mice. We propose that BHB may play a neuroprotective effect by enhancing glymphatic system function and attenuating neuroinflammatory subarachnoid hemorrhage.

Glymphatic pathway: An emerging perspective in the pathophysiology of neurodegenerative diseases

The central nervous system (CNS) is widely recognized as the only organ system without lymphatic capillaries to promote the removal of interstitial metabolic by-products. Thus, the newly identified glymphatic system which provides a pseudolymphatic activity in the nervous system has been focus of latest research in neurosciences. Also, findings reported that, sleep stimulates the elimination actions of glymphatic system and is linked to normal brain homeostatis. The CNS is cleared of potentially hazardous compounds via the glymphatic system, particularly during sleep. Any age-related alterations in brain functioning and pathophysiology of various neurodegenerative illnesses indicates the disturbance of the brain's glymphatic system. In this context, β-amyloid as well as tau leaves the CNS through the glymphatic system, it's functioning and CSF discharge markedly altered in elderly brains as per many findings. Thus, glymphatic failure may have a potential mechanism which may be therapeutically targetable in several neurodegenerative and age-associated cognitive diseases. Therefore, there is an urge to focus for more research into the connection among glymphatic system and several potential brain related diseases. Here, in our current review paper, we reviewed current research on the glymphatic system's involvement in a number of prevalent neurodegenerative and neuropsychiatric diseases and, we also discussed several therapeutic approaches, diet and life style modifications which might be used to acquire a more thorough performance and purpose of the glymphatic system to decipher novel prospects for clinical applicability for the management of these diseases.

1,7-diphenyl-4-hepten-3-one mitigates Alzheimer's-like pathology by inhibiting pyroptosis via activating the Nrf2 pathway

Pyroptosis-mediated neuron death plays a crucial role in neurodegenerative diseases, such as Alzheimer's disease (AD). However, the effect of 1,7-diphenyl-4-hepten-3-one (C1), a natural diarylheptanoid, on AD is unclear. Herein, we investigated the therapeutic effect of C1 on APP/PS1 mice and β-amyloid (Aβ)-induced HT22 cells. Our findings showed that C1 attenuated cognitive impairment and mitigated pathological damage in APP/PS1 mice. Furthermore, we found that C1 prevented oxidative stress damage and decreased the levels of pyroptosis-related proteins. In vitro experiments showed that C1 can improve the proliferation of Aβ-induced HT22 cells and decrease the levels of pyroptosis-related proteins in them. When Nrf2 was silenced, the positive effects of C1 in inhibiting pyroptosis were inhibited. Particularly, the production of pyroptosis-associated proteins, including NLRP3, GSDMD, and caspase-1, and the secretion of pro-inflammatory molecules, including IL-1 and IL-18, were increased. Altogether, these findings indicate that C1 can mitigate AD-like pathology via the inhibition of pyroptosis by activating the Nrf2 pathway. We believe that this study can provide alternative strategies for the prevention and treatment of AD.

Mobilizing endogenous neuroprotection: the mechanism of the protective effect of acupuncture on the brain after stroke

Given its high morbidity, disability, and mortality rates, ischemic stroke (IS) is a severe disease posing a substantial public health threat. Although early thrombolytic therapy is effective in IS treatment, the limited time frame for its administration presents a formidable challenge. Upon occurrence, IS triggers an ischemic cascade response, inducing the brain to generate endogenous protective mechanisms against excitotoxicity and inflammation, among other pathological processes. Stroke patients often experience limited recovery stages. As a result, activating their innate self-protective capacity [endogenous brain protection (EBP)] is essential for neurological function recovery. Acupuncture has exhibited clinical efficacy in cerebral ischemic stroke (CIS) treatment by promoting the human body's self-preservation and "Zheng Qi" (a term in traditional Chinese medicine (TCM) describing positive capabilities such as self-immunity, self-recovery, and disease prevention). According to research, acupuncture can modulate astrocyte activity, decrease oxidative stress (OS), and protect neurons by inhibiting excitotoxicity, inflammation, and apoptosis via activating endogenous protective mechanisms within the brain. Furthermore, acupuncture was found to modulate microglia transformation, thereby reducing inflammation and autoimmune responses, as well as promoting blood flow restoration by regulating the vasculature or the blood-brain barrier (BBB). However, the precise mechanism underlying these processes remains unclear. Consequently, this review aims to shed light on the potential acupuncture-induced endogenous neuroprotective mechanisms by critically examining experimental evidence on the preventive and therapeutic effects exerted by acupuncture on CIS. This review offers a theoretical foundation for acupuncture-based stroke treatment.

Overexpression of aquaporin-1 plays a vital role in proliferation, apoptosis, and pyroptosis of Wilms' tumor cells

BACKGROUND

Nephroblastoma, also known as Wilms' tumor (WT), is an embryonic malignant tumor and one of the most common malignant tumors in the abdominal region of children. The exact role and underlying mechanisms of aquaporin-1 (AQP1) in the occurrence and development of nephroblastoma remain unclear.

METHODS

After overexpression of AQP1, cell proliferation was assessed using the CCK-8 proliferation assay and EdU staining. Flow cytometry was employed to assess cell apoptosis, and Western blotting (WB) analysis was conducted to validate the expression of relevant protein markers. mRNA sequencing (mRNA-Seq) was performed on WT cells overexpressing AQP1 to predict and characterize the associated mechanisms. Transmission electron microscopy was utilized to observe changes in the ultrastructure of WT cells undergoing apoptosis and pyroptosis following AQP1 overexpression. Functional in vivo validation was conducted through animal experiments.

RESULTS

We validated that overexpression of AQP1 inhibited cell proliferation and promoted cell apoptosis and pyroptosis both in vitro and in vivo. mRNA-Seq analysis of WT cells with AQP1 overexpression suggested that these effects might be mediated through the inhibition of the JAK-STAT signaling pathway. Additionally, we discovered that overexpression of AQP1 activated the classical pyroptosis signaling pathway dependent on caspase-1, thereby promoting pyroptosis in WT.

CONCLUSION

These findings highlight the important functional role of AQP1 in the pathobiology of nephroblastoma, providing novel insights into the development of this disease. Moreover, these results offer new perspectives on the potential therapeutic targeting of AQP1 as a treatment strategy for nephroblastoma.

Neuroprotective effects of Jie-du-huo-xue decoction on microglia pyroptosis after cerebral ischemia and reperfusion--From the perspective of glial-vascular unit

ETHNOPHARMACOLOGICAL RELEVANCE

Ischemic stroke poses a serious risk to public health and quality of life. Jie-Du-Huo-Xue decoction (JDHXD) is a classical and well-known Chinese formula for stroke treatment, but the pharmacological mechanism is still unclear.

AIM OF THE STUDY

This study aims to investigate the mechanism underlying microglial pyroptosis and polarization, as well as the potential efficacy of JDHXD against cerebral ischemia-reperfusion injury (CIRI).

MATERIALS AND METHODS

Models of CIRI were established by the middle cerebral artery occlusion/reperfusion (MCAO/R) method in rats. In the first stage, 36 SD rats were randomly divided into sham group, I/R group, JDHXD-L group (5.36 g/kg/day), JDHXD-M group (10.71 g/kg/day), JDHXD-H group (21.42 g/kg/day), and positive drug edaravone group. The effectiveness of JDHXD on CIRI was confirmed by neurological function testing and cerebral infarct measuring. The best dose (JDXHD-M) was subsequently chosen to perform the tests that followed. In the second stage, 36 SD rats were randomly divided into the sham group, the I/R group, and the JDHXD-M group. Detection of nerve damage using Nissl staining, proteins of pyroptosis, Iba-1, and NeuN expressions were detected by western blotting, and proteins of microglial pyroptosis and M1/M2 phenotypic polarization were detected by immunofluorescence.

RESULTS

In rats after CIRI, JDHXD significantly reduced neurological impairment and cerebral infarction. In addition, JDHXD facilitated the M1-to-M2 transition of microglia in order to minimize neuroinflammation and improve anti-inflammatory repair. In addition, JDXHD inhibited microglial pyroptosis by blocking the cleavage of caspase-1 P10 and gasdermin D, hence reducing neuronal damage and enhancing neuronal survival following reperfusion. Interestingly, JDHXD also demonstrated a protective effect on the glial-vascular unit (GVU).

CONCLUSIONS

Our investigation demonstrated that JDHXD exerted a GVU-protective effect on CIRI rats by decreasing neuroinflammation-associated microglial pyroptosis, suppressing microglial M1 activation, and promoting microglial M2 activation.

Effects of amyloid β (Aβ)42 and Gasdermin D on the progression of Alzheimer's disease in vitro and in vivo through the regulation of astrocyte pyroptosis

PURPOSE

The study aimed to investigate whether astrocyte pyroptosis, and the subsequent neuroinflammatory response that exerts amyloid β (Aβ) neurotoxic effects, has an effect on endothelial cells, along with the underlying mechanisms.

METHODS

In vivo, 5 μL of disease venom was injected into the lateral ventricle of APP/PS1 mice for treatment. Pyroptosis was induced by treating astrocytes with Aβ42 in vitro. Small interfering RNA (siRNA) was used to silence caspase-1 and Gasdermin D (GSDMD) mRNA expression. Cell viability was determined using a CCK-8 detection kit. Scanning electron microscopy (SEM), Annexin V/propidium iodide (PI) double staining, RT-qPCR, immunofluorescence, western blotting, and enzyme-linked immunosorbent assay (ELISA) were used to detect cell pyroptosis. The degree of pathological damage to the brain and aortic tissue was assessed by hematoxylin-eosin staining and immunohistochemistry.

RESULTS

Aβ42 induced astrocyte pyroptosis dependent on the GSDMD/Gasdermin E (GSDME)/Caspase 11/NLRP3 pathway, releasing large amounts of inflammatory factors, such as TNF-α, IL-1α, IL-1β, and IL-18. Astrocyte pyroptosis caused endothelial cell dysfunction and release of large amounts of vasoconstrictors (ET and vWF). Knockdown of GSDMD reduced astrocyte pyroptosis in the cerebral cortex and hippocampal tissue, decreased the release of inflammatory factors IL-1 β and IL-18, reduced Aβ deposition and tau protein, increased the release of peripheral vasodilator substances (eNOS), and decreased the release of vasoconstrictor substances (ET, vWF), thereby reducing brain tissue damage and vascular injury in APP/PS1 mice.

CONCLUSION

Aβ42 induced astrocyte pyroptosis, while GSDMD knockout inhibited astrocyte pyroptosis, reduced the release of inflammatory factors, and alleviated brain tissue damage and vascular damage in APP/PS1 mice. Therefore, GSDMD is a novel therapeutic target for Alzheimer's disease.

PURPOSE

The study aimed to investigate whether astrocyte pyroptosis, and the subsequent neuroinflammatory response that exerts amyloid β (Aβ) neurotoxic effects, has an effect on endothelial cells, along with the underlying mechanisms.

METHODS

In vivo, 5 μL of disease venom was injected into the lateral ventricle of APP/PS1 mice for treatment. Pyroptosis was induced by treating astrocytes with Aβ42 in vitro. Small interfering RNA (siRNA) was used to silence caspase-1 and Gasdermin D (GSDMD) mRNA expression. Cell viability was determined using a CCK-8 detection kit. Scanning electron microscopy (SEM), Annexin V/propidium iodide (PI) double staining, RT-qPCR, immunofluorescence, western blotting, and enzyme-linked immunosorbent assay (ELISA) were used to detect cell pyroptosis. The degree of pathological damage to the brain and aortic tissue was assessed by hematoxylin-eosin staining and immunohistochemistry.

RESULTS

Aβ42 induced astrocyte pyroptosis dependent on the GSDMD/Gasdermin E (GSDME)/Caspase 11/NLRP3 pathway, releasing large amounts of inflammatory factors, such as TNF-α, IL-1α, IL-1β, and IL-18. Astrocyte pyroptosis caused endothelial cell dysfunction and release of large amounts of vasoconstrictors (ET and vWF). Knockdown of GSDMD reduced astrocyte pyroptosis in the cerebral cortex and hippocampal tissue, decreased the release of inflammatory factors IL-1 β and IL-18, reduced Aβ deposition and tau protein, increased the release of peripheral vasodilator substances (eNOS), and decreased the release of vasoconstrictor substances (ET, vWF), thereby reducing brain tissue damage and vascular injury in APP/PS1 mice.

CONCLUSION

Aβ42 induced astrocyte pyroptosis, while GSDMD knockout inhibited astrocyte pyroptosis, reduced the release of inflammatory factors, and alleviated brain tissue damage and vascular damage in APP/PS1 mice. Therefore, GSDMD is a novel therapeutic target for Alzheimer's disease.

Limb Remote Ischemic Postconditioning Improves Glymphatic Dysfunction After Cerebral Ischemia-Reperfusion Injury

BACKGROUND

Delayed neuronal damage can be caused or aggravated after cerebral ischemia-reperfusion (I/R) injury. Recent studies have shown that glymphatic system dysfunction after cerebral ischemia-reperfusion injury is involved in ischemic brain edema and neuroinflammation, thereby regulating cerebral ischemia-reperfusion injury. The aim of this study is to investigate the changes of glymphatic system after cerebral ischemia-reperfusion injury and whether limb remote ischemic postconditioning (LRIP) can improve the function of glymphatic system to protect the brain.

METHODS

To establish a focal brain I/R injury mouse model, this study utilized the middle cerebral artery occlusion/reperfusion (MCAO/R) method. The present study classified eight-week-old C57BL/6 male mice into three groups. The changes in glymphatic function in different periods of ischemia and reperfusion were analyzed through immunofluorescence, transmission electron microscopy (TEM), and Western-Blot (WB) assays. The contents of the evaluation included cerebrospinal fluid flow, swelling degree of brain tissue, aquaporin-4 (AQP4) expression and polarization, and amyloid-β (Aβ) excretion.

RESULTS

In the early stages of cerebral ischemia, cerebrospinal fluid (CSF) flow is disturbed, accompanied by a decrease in AQP4 polarization. The polarity of AQP4 decreased from 12 h to 72 h of reperfusion, the Aβ deposition. LRIP can increase the expression of β-DG and AQP4 polarization, reduce the deposition of Aβ, improve the function of the glymphatic system, and reduce the expression of AQP4 to play A protective role in brain.

CONCLUSION

Glymphatic system impaired after cerebral ischemia-reperfusion injury in mice. LRIP may play a neuroprotective role by improving glymphatic function after I/R.

Leveraging the glymphatic and meningeal lymphatic systems as therapeutic strategies in Alzheimer's disease: an updated overview of nonpharmacological therapies

Understanding and treating Alzheimer's disease (AD) has been a remarkable challenge for both scientists and physicians. Although the amyloid-beta and tau protein hypothesis have largely explained the key pathological features of the disease, the mechanisms by which such proteins accumulate and lead to disease progression are still unknown. Such lack of understanding disrupts the development of disease-modifying interventions, leaving a therapeutic gap that remains unsolved. Nonetheless, the recent discoveries of the glymphatic pathway and the meningeal lymphatic system as key components driving central solute clearance revealed another mechanism underlying AD pathogenesis. In this regard, this narrative review integrates the glymphatic and meningeal lymphatic systems as essential components involved in AD pathogenesis. Moreover, it discusses the emerging evidence suggesting that nutritional supplementation, non-invasive brain stimulation, and traditional Chinese medicine can improve the pathophysiology of the disease by increasing glymphatic and/or meningeal lymphatic function. Given that physical exercise is a well-regarded preventive and pro-cognitive intervention for dementia, we summarize the evidence suggesting the glymphatic system as a mediating mechanism of the physical exercise therapeutic effects in AD. Targeting these central solute clearance systems holds the promise of more effective treatment strategies.

The mechanisms underlying the actions of Xuefu Zhuyu decoction pretreatment against neurological deficits after ischemic stroke in mice: The mediation of glymphatic function by aquaporin-4 and its anchoring proteins

Ischemic stroke (IS) has been associated with an impairment in glymphatic function. Xuefu Zhuyu Decoction (XFZYD) is widely used in the prevention and treatment of ischemic stroke. We hypothesized that Xuefu Zhuyu decoction pretreatment could attenuate early neurological deficits after ischemic stroke by enhancing the function of the glymphatic system. To prove our hypothesis, we carried out temporary middle cerebral artery occlusion and reperfusion surgery on C57BL/6 mice and then measured neurological score, infarct size and performed hematoxylin-eosin staining to assess stroke outcomes after 24 h of reperfusion. Subsequently, we injected fluorescent tracers in to the cisterna magna and evaluated tracer distribution in coronal brain sections. The polarization of aquaporin-4 (AQP4), colocalization of aquaporin-4, α-dystroglycan, β-dystroglycan and agrin were determined by immunofluorescence. Our research showed that pretreatment with Xuefu Zhuyu decoction significantly alleviated neurological scores, neurological deficits and pathological abnormalities in a mouse model of ischemic stroke. Importantly, Xuefu Zhuyu decoction pretreatment enhanced cerebrospinal fluid influx, protected aquaporin-4 depolarization and promoted the colocalization of aquaporin-4 with its anchoring proteins in the brain. Our findings highlight novel mechanisms underlying the neuroprotective effect of Xuefu Zhuyu decoction pretreatment on ischemic stroke-induced brain damage through the glymphatic system. Xuefu Zhuyu decoction pretreatment may offer a promising approach to slow the onset and progression of ischemic stroke.

Pyroptosis as a candidate therapeutic target for Alzheimer’s disease

Pyroptosis is a form of cell death mediated by inflammasomes and gasdermins, and the relevance of pyroptosis to neurodegenerative diseases is currently receiving increasing attention. Alzheimer’s disease (AD) is a chronic progressive neurodegenerative disease that is closely associated with neuroinflammation. Its main pathological features include β-amyloid (Aβ) deposition, Tau protein hyperphosphorylation and neuronal loss. Aβ, tau-induced microglia pyroptosis and polarization leading to neuroinflammation play an important role in the pathogenesis of AD. Studying the pathogenesis and treatment of AD based on cellular pyroptosis has become a new direction in AD research. In this paper, we review the research progress of pyroptosis and will focus on the pathogenic roles of pyroptosis in AD and the role of targeted inhibition of inflammasome-dependent pyroptosis in AD treatment. These results deepen our understanding of the pathogenesis of AD and provide ideas for the development of new drugs based on the regulation of pyroptosis in AD patients.