USP14 inhibition promotes recovery by protecting BBB integrity and attenuating neuroinflammation in MCAO mice

Inhibition of P2X7R by Hypericin improves Diabetic Cardiac Autonomic Neuropathy through the proteasome- Nrf2 - GPX4 signaling axis

Hypericin (HYP), a primary active compound derived from hypericum perforatum has been studied in the context of diabetes. The purpose of this study is to observe whether HYP can improve diabetic cardiac autonomic neuropathy (DCAN) and its possible mechanism. The current findings suggest that multiple drivers of ferroptosis in DCAN converge on the antioxidant protein nuclear factor erythroid 2-related factor 2(Nrf2). Overactivated P2X7 receptor (P2X7R) increases Nrf2 degradation by increasing proteasome activity through calcium ion accumulation. This work showed that HYP inhibited P2X7R expression, leading to elevated Nrf2 levels, thereby counteracting ferroptosis. This inhibition improves abnormal changes in cardiac function during the pathological process of DCAN in diabetic rats, including heart rate (HR), blood pressure (BP), heart rate variability (HRV), and sympathetic nerve discharge (SND). In summary, HYP enhances Nrf2 protein levels by suppressing P2X7R expression, reducing calcium-induced proteasome activity, and inhibits ferroptosis and inflammation. Thus, HYP alleviated DCAN progression.

Ultrasmall Nanoparticles Mitigate Tau Hyperphosphorylation to Restore Synaptic Integrity and Boost Cognitive Function in Alzheimer's Disease

Tau hyperphosphorylation represents a critical pathological hallmark of Alzheimer's disease (AD), a prevalent neurodegenerative disorder characterized by progressive cognitive decline. The ubiquitin-specific proteases 14 (USP14) impairs proteasomal function and accelerates hyperphosphorylated Tau accumulation, making it an attractive therapeutic target for modulating the ubiquitin-proteasome pathway in AD treatment. In this study, it is reported that wogonoside-functionalized ultrasmall Cu2-xSe nanoparticles (CSPW NPs) significantly reduce hyperphosphorylated Tau accumulation and alleviate AD symptoms. The therapeutic mechanism involves activation of the ubiquitin-proteasome pathway through USP14 inhibition by CSPW NPs, thereby preventing hyperphosphorylated Tau accumulation. Furthermore, after cell membrane coating (CSPW@CM NPs), these nanoparticles efficiently cross the blood-brain barrier with focused ultrasound assistance and accumulate in the brain to target neurons. Within neurons, they inhibit USP14, reduce phosphorylated Tau deposition, enhance microtubule stability, mitigate synaptic loss, restore synaptic integrity, and ultimately alleviate cognitive dysfunction in AD mice. The findings highlight the substantial potential of USP14 modulation for mitigating Tau hyperphosphorylation in the treatment of AD and related tauopathies.

Expression of BDNF in the Cortex and Hippocampus of Mice With Middle Cerebral Artery Occlusion

BACKGROUND/AIM

Stroke is a cerebrovascular disease with high mortality and disability, causing motor dysfunction and cognitive impairments. Middle cerebral artery occlusion (MCAO) mouse models of ischemic stroke are used for identifying therapeutic targets. Ischemic insults to the brain alter brain-derived neurotrophic factor (BDNF) expression in cortical and hippocampal neurons. In the present study, we investigated BDNF expression in the cortex and hippocampus of mice following MCAO.

MATERIALS AND METHODS

Monofilament sutures coated with silicone rubber were introduced into the common carotid artery and occluded middle cerebral artery. The filament was withdrawn for reperfusion after 0.5 h. BDNF protein expression was measured using western blot. Immunofluorescence was performed with anti-NeuN and anti-BDNF antibodies.

RESULTS

BDNF expression in the cerebral cortex and hippocampus was decreased one and three days after MCAO, compared to the control group (unoperated mice). BDNF was expressed in NeuN-positive neurons in the dentate gyrus of the hippocampus and motor cortex of the MCAO and control groups.

CONCLUSION

MCAO in mice reduced the expression of BDNF in mature neurons of both the motor cortex and hippocampus at one and three days after surgery.

Acori Tatarinowii Rhizoma regulates OCT3/OATP2 and P-gp/MRP1 to "guide medicines upwards" in Kai-Xin-San to treat Alzheimer's disease

ETHNOPHARMACOLOGICAL RELEVANCE

Kai-Xin-San (KXS) has a significant effect therapeutic on Alzheimer's disease (AD) in clinical practice. According to the compatibility theory of traditional Chinese medicine, Acori Tatarinowii Rhizoma (ATR) serves as the guiding drug in the KXS formulation and is believed to enhance the bioavailability and brain tissue distribution of the other drugs. However, the mechanism underlying the "guiding medicine upwards" effect of ATR in KXS remains unexplored.

AIM OF THE STUDY

The aim of this study is to investigate the role of ATR in the efficacy of KXS on amyloid precursor protein/presenilin 1 (APP/PS1) mice, as well as its impact on the brain tissue distribution of other active ingredients in the KXS formula, and to elucidate the mechanism of ATR's "guiding medicine upwards" effect in KXS.

MATERIALS AND METHODS

The pharmacodynamic effects of ATR in KXS were assessed through behavioral tests, immunohistochemical staining, and Nissl staining. Additionally, the levels of inflammatory factors, as well as the activities of malondialdehyde, superoxide dismutase, and acetylcholinesterase, were measured using enzyme-linked immunosorbent assay kits. Subsequently, the effect of ATR on the ultrastructure of the blood-brain barrier (BBB) in APP/PS1 mice was observed using transmission electron microscopy (TEM), and the pharmacodynamic components of KXS in cerebrospinal fluid were quantified by ultra-high-performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS/MS). Furthermore, Western blot (WB) analysis was used to quantitatively assess the expression of tight junction proteins (Claudin-5, Occludin, and ZO-1) and transporters (OCT3, OATP2, P-gp, and MRP1) in the BBB. Finally, bEND.3 cells and astrocyte cells were co-cultured to validate the effect of ATR on KXS. The expressions of OCT3/OATP2 and P-gp/MRP1 in BBB cell model were determined by WB and the content of pharmacodynamic components in the lower chamber of the transwell were also analyzed by UPLC-MS/MS.

RESULTS

Behavioral test results suggest that KXS significantly improved the learning and memory capacities of APP/PS1 mice compared to the ATR-free KXS group. Furthermore, KXS was more effective in reducing amyloid-β protein deposition in the brain and repairing damaged neurons in the CA1 and CA3 regions than ATR-free KXS. Notably, KXS significantly reversed the pathological biochemical indices compared to the ATR-free KXS group. These results indicate that ATR has a positive effect on the pharmacodynamics of KXS in treating AD. Most importantly, TEM results revealed that KXS repaired the damaged BBB in AD mice, and ATR contributed to the improvement of BBB integrity. Furthermore, KXS and ATR increased the expression levels of Claudin-5, Occludin, and ZO-1 proteins in AD mice. Meanwhile, the levels of ginsenoside Rg1, ginsenoside Rb1, and polygalaxanthone III in the cerebrospinal fluid of the KXS group were 1.47, 1.39, and 2.02 times higher than those in the ATR-free KXS group, respectively. WB results showed that ATR and KXS significantly upregulated the expression of OCT3/OATP2 uptake transporters and downregulated the expression of P-gp/MRP1 efflux transporters compared to ATR-free KXS. Concurrently, in vitro BBB cell experimental results suggest that ATR promoted the transport of ginsenoside Rg1, ginsenoside Rb1, and polygalaxanthone III across BBB cells in KXS, and the regulation of OCT3/OATP2 and P-gp/MRP1 expression was consistent with the in vivo trends observed in AD mice.

CONCLUSIONS

ATR plays a critical role in enhancing the efficacy of KXS in treating AD and facilitates the entry of other pharmacodynamic components into the brain. The mechanism underlying the "guiding medicine upwards" effect of ATR may involve the regulation of OCT3/OATP2 and P-gp/MRP1 transporters.

Ubiquitin-specific peptidase 14 promotes neuron injury by stabilizing acyl-CoA synthetase long-chain family member 4 through deubiquitination

Objective

Ubiquitin-specific peptidase 14 (USP14) may be a target for stroke treatment. Our study aims to explore the molecular mechanism of USP14 in the stroke process.

Material and Methods

A stroke cell model was constructed using oxygen-glucose deprivation/reoxygenation (OGD/R)-induced SK-N-SH cells, and cell growth was assessed using cell counting kit 8 assay, EdU assay, and flow cytometry. Proinflammatory cytokine levels were tested through an enzyme-linked immunosorbent assay. The levels of USP14 and acyl-CoA synthetase long-chain family member 4 (ACSL4) were determined through Western blot and quantitative real-time polymerase chain reaction, whereas the interaction of USP14 and ACS14 was evaluated by co-immunoprecipitation assay.

Results

OGD/R-induced SK-N-SH cell injury by enhancing ferroptosis and the knockdown of USP14 inhibited OGD/R-induced cell inflammation, apoptosis, and ferroptosis. Moreover, USP14 enhanced ACSL4 protein expression through deubiquitination. ACSL4 silencing mitigated neuron injury, and ACSL4 upregulation abolished USP14 knockdown-mediated inhibition of neuron injury.

Conclusion

USP14 can enhance neuron injury through stabilizing ACSL4 protein expression.

Buyang Huanwu Decoction prevents hemorrhagic transformation after delayed t-PA infusion via inhibiting NLRP3 inflammasome/pyroptosis associated with microglial PGC-1α

ETHNOPHARMACOLOGICAL RELEVANCE

Delayed tissue-type plasminogen activator (t-PA) thrombolysis, which has a restrictive therapeutic time window within 4.5 h following ischemic stroke (IS), increases the risk of hemorrhagic transformation (HT) and subsequent neurotoxicity. Studies have shown that the NLRP3 inflammasome activation reversely regulated by the PGC-1α leads to microglial polarization and pyroptosis to cause damage to nerve cells and the blood-brain barrier. The effect of Buyang Huanwu Decoction (BHD), a traditional Chinese medicine prescription widely used in the recovery of IS, on HT injury after delayed t-PA treatment had been found with clinical studies, while the underlying mechanisms are reminded to be further clarified.

AIM OF THE STUDY

This study sought to investigate the therapeutic effect and the underlying mechanisms of BHD in ischemic rat brains with delayed t-PA treatment.

MATERIALS AND METHODS

The components of BHD extracts were identified by High Performance Liquid Chromatography (HPLC) and the effective components in the rat brains from BHD were analyzed by liquid chromatography-mass spectrometry (LC-MS). In vivo experiment was carried out by 5 h of middle cerebral artery occlusion (MCAO) following by t-PA infusion for 0.5 h plus reperfusion 19 h, while the in vitro BV2 cells were stimulated by lipopolysaccharide (LPS)-adenosine triphosphate (ATP) to activate microglia pyroptosis, of which the MCC950 (NLRP3 inhibitor) and NSA (GSDMD inhibitor) were adopted as reverse validation. PGC-1α siRNA was utilized to study the mechanisms of BHD against microglial polarization and pyroptosis in BV2 cells.

RESULTS

HPLC analysis demonstrated the fingerprint of BHD with six reference standards (Hydroxysafflor yellow A, Calycosin-7-glucoside, Paeoniflorin, Formononetin, Ferulic acid and Amygdalin), the last two of which can be found in rat brains by LC-MS analysis. In the following experiments, we found the major discoveries as follow: (1) BHD improved the neurological outcomes, the structural integrity of the blood-brain barrier and the neuronal structure in HT rats with MCAO following by delayed t-PA infusion; (2) the presence of t-PA promoted the suppression of PGC-1α and the activation of microglial NLRP3 inflammasome and pyroptosis in the HT rats; (3) BHD promoted the transformation of microglia from M1 to M2 type for inhibiting inflammatory response; (4) BHD restrained NLRP3 inflammasome/pyroptosis activation in microglia, prevented the translocations of NF-κB into the nucleus, as well as enhanced microglia-specific PGC-1α in ischemic rats following t-PA delayed thrombolysis; (5) BHD suppressed NLRP3 inflammasome assembly and increased PGC-1α expression in the LPS-ATP-induced BV2 cells; (6) PGC-1α silencing withdrew the protective role of BHD against NLRP3 inflammasome/pyroptosis.

CONCLUSION

Mechanistically, BHD existed the protective effect against HT injury after delayed t-PA treatment through up-regulating microglial PGC-1α to inhibit NLRP3 inflammasome and pyroptosis, and serves as a potential adjuvant therapy for HT injury.

Pharmacological inhibition of USP14 delays proteostasis-associated aging in a proteasome-dependent but foxo-independent manner

Aging is often accompanied by a decline in proteostasis, manifested as an increased propensity for misfolded protein aggregates, which are prevented by protein quality control systems, such as the ubiquitin-proteasome system (UPS) and macroautophagy/autophagy. Although the role of the UPS and autophagy in slowing age-induced proteostasis decline has been elucidated, limited information is available on how these pathways can be activated in a collaborative manner to delay proteostasis-associated aging. Here, we show that activation of the UPS via the pharmacological inhibition of USP14 (ubiquitin specific peptidase 14) using IU1 improves proteostasis and autophagy decline caused by aging or proteostatic stress in Drosophila and human cells. Treatment with IU1 not only alleviated the aggregation of polyubiquitinated proteins in aging Drosophila flight muscles but also extended the fly lifespan with enhanced locomotive activity via simultaneous activation of the UPS and autophagy. Interestingly, the effect of this drug disappeared when proteasomal activity was inhibited, but was evident upon proteostasis disruption by foxo mutation. Overall, our findings shed light on potential strategies to efficiently ameliorate age-associated pathologies associated with perturbed proteostasis.Abbreviations: AAAs: amino acid analogs; foxo: forkhead box, sub-group O; IFMs: indirect flight muscles; UPS: ubiquitin-proteasome system; USP14: ubiquitin specific peptidase 14.

MicroRNA-199a-5p attenuates blood-brain barrier disruption following ischemic stroke by regulating PI3K/Akt signaling pathway

OBJECTIVE

To explore whether miR-199a-5p regulated BBB integrity through PI3K/Akt pathway after ischemia stroke.

METHODS

Adult male Sprague-Dawley rats with permanent middle cerebral artery occlusion(MCAO) were used in experiment. The Ludmila Belayev 12-point scoring was used to measure the neurological function of MCAO rats. The Evans Blue Stain, immunofluorescence staining, western-blotting and RT-PCR were performed to evaluate the effects of miR-199a-5p mimic on BBB integrity in rats following MCAO.

RESULTS

The result suggested that miR-199a-5p mimic treatment possessed the potential to boost proprioception and motor activity of MCAO rats. MiR-199a-5p decreased the expression of PIK3R2 after MCAO, activated Akt signaling pathway, and increased the expression of Claudin-5 and VEGF in the ischemic penumbra. Furthermore, miR-199a-5p alleviated inflammation after cerebral ischemia. BBB leakage and neurocyte apoptosis were cut down in MCAO rats treated with miR-199a-5p mimic.

CONCLUSIONS

MiR-199a-5p mimic decreased the expression of PIK3R2 and activated Akt signaling pathway after ischemia stroke, reduced the expression of inflammatory cytokines, and attenuated BBB disruption after ischemic stroke.

β-1,4-Galactosyltransferase 1 protects against cerebral ischemia injury in mice by suppressing ferroptosis via the TAZ/Nrf2/HO-1 signaling pathway

BACKGROUND

Ischemic stroke leads a primary cause of mortality in human diseases, with a high disability rate worldwide. This study aims to investigate the function of β-1,4-galactosyltransferase 1 (B4galt1) in mouse brain ischemia/reperfusion (I/R) injury.

METHODS

Recombinant human B4galt1 (rh-B4galt1) was intranasally administered to the mice model of middle cerebral artery occlusion (MCAO)/reperfusion. In this study, the impact of rh-B4galt1 on cerebral injury assessed using multiple methods, including the neurological disability status scale, 2,3,5-triphenyltetrazolium chloride (TTC), Nissl and TUNEL staining. This study utilized laser speckle Doppler flowmeter to monitor the cerebral blood flow. Western blotting was performed to assess the protein expression levels, and fluorescence-labeled dihydroethidium method was performed to determine the superoxide anion generation. Assay kits were used for the measurement of iron, malondialdehyde (MDA) and glutathione (GSH) levels.

RESULTS

We demonstrated that rh-B4galt1 markedly improved neurological function, reduced cerebral infarct volume and preserved the completeness of blood-brain barrier (BBB) for preventing damage. These findings further illustrated that rh-B4galt1 alleviated oxidative stress, lipid peroxidation, as well as iron deposition induced by I/R. The vital role of ferroptosis was proved in brain injury. Furthermore, the rh-B4galt1 could increase the levels of TAZ, Nrf2 and HO-1 after I/R. And TAZ-siRNA and ML385 reversed the neuroprotective effects of rh-B4galt1.

CONCLUSIONS

The results indicated that rh-B4galt1 implements neuroprotective effects by modulating ferroptosis, primarily via upregulating TAZ/Nrf2/HO-1 pathway. Thus, B4galt1 could be seen as a promising novel objective for ischemic stroke therapy.

Usp14 deficiency removes α-synuclein by regulating S100A8/A9 in Parkinson's disease

Ubiquitin-proteasome system dysfunction triggers α-synuclein aggregation, a hallmark of neurodegenerative diseases, such as Parkinson's disease (PD). However, the crosstalk between deubiquitinating enzyme (DUBs) and α-synuclein pathology remains unclear. In this study, we observed a decrease in the level of ubiquitin-specific protease 14 (USP14), a DUB, in the cerebrospinal fluid (CSF) of PD patients, particularly females. Moreover, CSF USP14 exhibited a dual correlation with α-synuclein in male and female PD patients. To investigate the impact of USP14 deficiency, we crossed USP14 heterozygous mouse (USP14+/-) with transgenic A53T PD mouse (A53T-Tg) or injected adeno-associated virus (AAV) carrying human α-synuclein (AAV-hα-Syn) in USP14+/- mice. We found that Usp14 deficiency improved the behavioral abnormities and pathological α-synuclein deposition in female A53T-Tg or AAV-hα-Syn mice. Additionally, Usp14 inactivation attenuates the pro-inflammatory response in female AAV-hα-Syn mice, whereas Usp14 inactivation demonstrated opposite effects in male AAV-hα-Syn mice. Mechanistically, the heterodimeric protein S100A8/A9 may be the downstream target of Usp14 deficiency in female mouse models of α-synucleinopathies. Furthermore, upregulated S100A8/A9 was responsible for α-synuclein degradation by autophagy and the suppression of the pro-inflammatory response in microglia after Usp14 knockdown. Consequently, our study suggests that USP14 could serve as a novel therapeutic target in PD.

FGF17 protects cerebral ischemia reperfusion-induced blood-brain barrier disruption via FGF receptor 3-mediated PI3K/AKT signaling pathway

Maintaining blood-brain barrier (BBB) integrity is critical components of therapeutic approach for ischemic stroke. Fibroblast growth factor 17 (FGF17), a member of FGF8 superfamily, exhibits the strongest expression throughout the wall of all major arteries during development. However, its molecular action and potential protective role on brain endothelial cells after stroke remains unclear. Here, we observed reduced levels of FGF17 in the serum of patients with ischemic stroke, as well as in the brains of mice subjected to middle cerebral artery occlusion (MCAO) injury and oxygen-glucose deprivation/reoxygenation (OGD/R)-induced brain microvascular endothelial cells (bEnd.3) cells. Moreover, treatment with exogenous recombinant human FGF17 (rhFGF17) decreased infarct volume, improved neurological deficits, reduced Evans Blue leakage and upregulated the expression of tight junctions in MCAO-injured mice. Meanwhile, rhFGF17 increased cell viability, enhanced trans-endothelial electrical resistance, reduced sodium fluorescein leakage, and alleviated reactive oxygen species (ROS) generation in OGD/R-induced bEnd.3 cells. Mechanistically, the treatment with rhFGF17 resulted in nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear accumulation and upregulation of heme oxygenase-1 (HO-1) expression. Additionally, based on in-vivo and in-vitro research, rhFGF17 exerted protective effects against ischemia/reperfusion (I/R) -induced BBB disruption and endothelial cell apoptosis through the activation of the FGF receptor 3/PI3K/AKT signaling pathway. Overall, our findings indicated that FGF17 may hold promise as a novel therapeutic strategy for ischemic stroke patients.

Ubiquitous regulation of cerebrovascular diseases by ubiquitin-modifying enzymes

Cerebrovascular diseases (CVDs) are a major threat to global health. Elucidation of the molecular mechanisms underlying the pathology of CVDs is critical for the development of efficacious preventative and therapeutic approaches. Accumulating studies have highlighted the significance of ubiquitin-modifying enzymes (UMEs) in the regulation of CVDs. UMEs are a group of enzymes that orchestrate ubiquitination, a post-translational modification tightly involved in CVDs. Functionally, UMEs regulate multiple pathological processes in ischemic and hemorrhagic stroke, moyamoya disease, and atherosclerosis. Considering the important roles of UMEs in CVDs, they may become novel druggable targets for these diseases. Besides, techniques applying UMEs, such as proteolysis-targeting chimera and deubiquitinase-targeting chimera, may also revolutionize the therapy of CVDs in the future.

The regulatory role and mechanism of USP14 in endothelial cell pyroptosis induced by coronary heart disease

OBJECTIVE

The present study probes into the role and mechanism of ubiquitin specific peptidase 14 (USP14) in coronary heart disease (CHD)-triggered endothelial cell pyroptosis.

METHODS

An in vitro CHD model was established by inducing human coronary artery endothelial cells (HCAECs) with oxidized low-density lipoprotein (ox-LDL). HCAECs were transfected with si-USP14, followed by evaluation of cell viability by CCK-8 assay, detection of lactate dehydrogenase (LDH) activity by assay kit, detection of USP14, miR-15b-5p, NLRP3, GSDMD-N, and Cleaved-Caspase-1 expressions by qRT-PCR or Western blot, as well as IL-1β and IL-18 concentrations by ELISA. Co-IP confirmed the binding between USP14 and NLRP3. The ubiquitination level of NLRP3 in cells was measured after protease inhibitor MG132 treatment. Dual-luciferase reporter assay verified the targeting relationship between miR-15b-5p and USP14.

RESULTS

USP14 and NLRP3 were highly expressed but miR-15b-5p was poorly expressed in ox-LDL-exposed HCAECs. USP14 silencing strengthened the viability of ox-LDL-exposed HCAECs, reduced the intracellular LDH activity, and diminished the NLRP3, GSDMD-N, Cleaved-Caspase-1, IL-1β, and IL-18 expressions. USP14 bound to NLRP3 protein and curbed its ubiquitination. Repression of NLRP3 ubiquitination counteracted the inhibitory effect of USP14 silencing on HCAEC pyroptosis. miR-15b-5p restrained USP14 transcription and protein expression. miR-15b-5p overexpression alleviated HCAEC pyroptosis by suppressing USP14/NLRP3.

CONCLUSION

USP14 stabilizes NLRP3 protein expression through deubiquitination, thereby facilitating endothelial cell pyroptosis in CHD. miR-15b-5p restrains endothelial cell pyroptosis by targeting USP14 expression.