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Alzheimer's disease (AD) is one of the most common causes of neurodegenerative diseases in the elderly. The accumulation of amyloid‐β (Aβ) peptides is one of the pathological hallmarks of AD and leads to the impairments of synaptic plasticity and cognitive function. The transient receptor potential vanilloid 1 (TRPV1), a nonselective cation channel, is involved in synaptic plasticity and memory. However, the role of TRPV1 in AD pathogenesis remains largely elusive. Here, we reported that the expression of TRPV1 was decreased in the brain of APP23/PS45 double transgenic AD model mice. Genetic upregulation of TRPV1 by adeno‐associated virus (AAV) inhibited the APP processing and Aβ deposition in AD model mice. Meanwhile, upregulation of TRPV1 ameliorated the deficits of hippocampal CA1 long‐term potentiation (LTP) and spatial learning and memory through inhibiting GluA2‐containing α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid receptor (AMPAR) endocytosis. Furthermore, pharmacological activation of TRPV1 by capsaicin (1 mg/kg, i.p.), an agonist of TRPV1, dramatically reversed the impairments of hippocampal CA1 LTP and spatial learning and memory in AD model mice. Taken together, these results indicate that TRPV1 activation effectively ameliorates cognitive and synaptic functions through inhibiting AMPAR endocytosis in AD model mice and could be a novel molecule for AD treatment. Aging reduces TRPV1 activity to lead to AMPAR endocytosis and active APP processing to promote Aβ deposition. Increased AMPAR endocytosis and Aβ result in LTP impairment and subsequently induce memory deficits. Genetic upregulation or pharmacological activation of TRPV1 is able to reverse AD‐related neuropathologies in AD model mice.

Posttranslational modification (PTM) of the amyloid precursor protein (APP) plays a critical role in Alzheimer’s disease (AD). Recent evidence reveals that lactylation modification, as a novel PTM, is implicated in the occurrence and development of AD. However, whether and how APP lactylation contributes to both the pathogenesis and cognitive function in AD remains unknown. Here, we observed a reduction in APP lactylation in AD patients and AD model mice and cells. Proteomic mass spectrometry analysis further identified lysine 612 (APP-K612la) as a crucial site for APP lactylation, influencing APP amyloidogenic processing. A lactyl-mimicking mutant (APP K612T ) reduced amyloid-β peptide (Aβ) generation and slowed down cognitive deficits in vivo. Mechanistically, APP K612T appeared to facilitate APP trafficking and metabolism. However, lactylated APP entering the endosome inhibited its binding to BACE1, suppressing subsequent cleavage. Instead, it promoted protein interaction between APP and CD2-associated protein (CD2AP), thereby accelerating the endosomal-lysosomal degradation pathway of APP. In the APP23/PS45 double-transgenic mouse model of AD, APP-Kla was susceptible to L-lactate regulation, which reduced Aβ pathology and repaired spatial learning and memory deficits. Thus, these findings suggest that targeting APP lactylation may be a promising therapeutic strategy for AD in humans.

Hypoxic-ischemic encephalopathy (HIE) is a main cause of mortality and severe neurologic impairment in the perinatal and neonatal period. However, few satisfactory therapeutic strategies are available. Here, we reported that a rapid nuclear translocation of phosphatase and tensin homolog deleted on chromosome TEN (PTEN) is an essential step in hypoxic-ischemic brain damage (HIBD)- and oxygen-glucose deprivation (OGD)-induced neuronal injures both in vivo and in vitro. In addition, we found that OGD-induced nuclear translocation of PTEN is dependent on PTEN mono-ubiquitination at the lysine 13 residue (K13) that is mediated by neural precursor cell expressed developmentally downregulated protein 4-1 (NEDD4-1). Importantly, we for the first time identified α- and γ-adaptin binding protein (Aagab) as a novel NEDD4-1 regulator to regulate the level of NEDD4-1, subsequently mediating Pten nuclear translocation. Finally, we demonstrated that genetic upregulation of Aagab or application of Tat-K13 peptide (a short interference peptide that flanks K13 residue of PTEN) not only reduced Pten nuclear translocation, but also significantly alleviated the deficits of myodynamia, motor and spatial learning and memory in HIBD model rats. These results suggest that Aagab may serve as a regulator of NEDD4-1-mediated Pten nuclear translocation to promote functional recovery following HIBD in neonatal rats, and provide a new potential therapeutic target to guide the clinical treatment for HIE.

Background The nucleotide-binding oligomeric domain (NOD)-like receptor protein 3 (NLRP3) inflammasome is believed to be a key mediator of neuroinflammation and subsequent secondary brain injury induced by ischemic stroke. However, the role and underlying mechanism of the NLRP3 inflammasome in neonates with hypoxic-ischemic encephalopathy (HIE) are still unclear. Methods The protein expressions of the NLRP3 inflammasome including NLRP3, cysteinyl aspartate specific proteinase-1 (caspase-1) and interleukin-1β (IL-1β), the α-amino-3-hydroxy-5-methyl-4-isoxazole-propionicacid receptor (AMPAR) subunit, and the ATPase valosin-containing protein (VCP/p97), were determined by Western blotting. The interaction between p97 and AMPA glutamate receptor 1 (GluA1) was determined by co-immunoprecipitation. The histopathological level of hypoxic-ischemic brain damage (HIBD) was determined by triphenyltetrazolium chloride (TTC) staining. Polymerase chain reaction (PCR) and Western blotting were used to confirm the genotype of the knockout mice. Motor functions, including myodynamia and coordination, were evaluated by using grasping and rotarod tests. Hippocampus-dependent spatial cognitive function was measured by using the Morris-water maze (MWM). Results We reported that the NLRP3 inflammasome signaling pathway, such as NLRP3, caspase-1 and IL-1β, was activated in rats with HIBD and oxygen-glucose deprivation (OGD)-treated cultured primary neurons. Further studies showed that the protein level of the AMPAR GluA1 subunit on the hippocampal postsynaptic membrane was significantly decreased in rats with HIBD, and it could be restored to control levels after treatment with the specific caspase-1 inhibitor AC-YVAD-CMK. Similarly, in vitro studies showed that OGD reduced GluA1 protein levels on the plasma membrane in cultured primary neurons, whereas AC-YVAD-CMK treatment restored this reduction. Importantly, we showed that OGD treatment obviously enhanced the interaction between p97 and GluA1, while AC-YVAD-CMK treatment promoted the dissociation of p97 from the GluA1 complex and consequently facilitated the localization of GluA1 on the plasma membrane of cultured primary neurons. Finally, we reported that the deficits in motor function, learning and memory in animals with HIBD, were ameliorated by pharmacological intervention or genetic ablation of caspase-1. Conclusion Inhibiting the NLRP3 inflammasome signaling pathway promotes neurological recovery in animals with HIBD by increasing p97-mediated surface GluA1 expression, thereby providing new insight into HIE therapy.

The imbalance between neuronal excitation and inhibition (E/I) in neural circuit has been considered to be at the root of numerous brain disorders. We recently reported a novel feedback crosstalk between the excitatory neurotransmitter glutamate and inhibitory γ‐aminobutyric acid type A receptor (GABAAR)‐glutamate allosteric potentiation of GABAAR functions through a direct binding of glutamate to the GABAAR itself. Here, we investigated the physiological significance and pathological implications of this cross‐talk by generating the β3E182G knock‐in (KI) mice. We found that β3E182G KI, while had little effect on basal GABAAR‐mediated synaptic transmission, significantly reduced glutamate potentiation of GABAAR‐mediated responses. These KI mice displayed lower thresholds for noxious stimuli, higher susceptibility to seizures and enhanced hippocampus‐related learning and memory. Additionally, the KI mice exhibited impaired social interactions and decreased anxiety‐like behaviors. Importantly, hippocampal overexpression of wild‐type β3‐containing GABAARs was sufficient to rescue the deficits of glutamate potentiation of GABAAR‐mediated responses, hippocampus‐related behavioral abnormalities of increased epileptic susceptibility, and impaired social interactions. Our data indicate that the novel crosstalk among excitatory glutamate and inhibitory GABAAR functions as a homeostatic mechanism in fine‐tuning neuronal E/I balance, thereby playing an essential role in ensuring normal brain functioning. The β3E182G single mutation is sufficient to eliminate the glutamate potentiation of GABAAR responses, and to cause electrophysiological and behavioral abnormalities, whereas bilateral hippocampal overexpressions of wild type β3‐containing GABAARs rescue these abnormalities. We therefore revealed that glutamate‐GABAAR crosstalk plays a homeostatic role in maintaining a proper balance between neuronal excitation and inhibition under both physiological and pathological conditions.

Irritable bowel syndrome (IBS) is a prevalent functional gastrointestinal disorder characterized by abdominal pain and changes in bowel habits. Cinnamaldehyde (CA) possesses anti‐inflammatory, antibacterial, and digestive‐regulatory properties. However, its therapeutic potential for IBS and mechanisms are not understood. We employed network pharmacology to identify potential targets and pathways of CA against IBS. Core targets were validated through molecular docking, and further verified in an IBS rat model induced by neonatal maternal separation (NMS) and water avoidance stress (WAS). Network pharmacology identified 139 potential targets of CA related to IBS. Gene Ontology (GO) enrichment analysis highlighted key biological processes, cellular components, and molecular functions. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis suggested involvement of pathways such as nitrogen metabolism, tyrosine metabolism, and cocaine addiction. A protein–protein interaction (PPI) network revealed 11 major targets, and molecular docking demonstrated strong binding affinities between CA and several targets, particularly MAOB , PARP1 , HDAC1 , JAK2 , and MMP2 . Animal experiments confirmed that CA significantly reduces MAOB , as well as TNF‐α, IL‐6, and IL‐1β levels, thereby alleviating visceral hypersensitivity and anxiety and depression‐like behaviors in IBS rats. These findings provide a scientific basis for developing CA as a potential natural therapeutic agent for IBS.

Posttranslational modification (???) of the amyloid precursor protein (APP) plays a critical role in Alzheimer's disease (AD). Recent evidence reveals that lactylation modification, as a novel PTM, is implicated in the occurrence and development of AD. However, whether and how APP lactylation contributes to both the pathogenesis and cognitive function in AD remains unknown. Here, we observed a reduction in APP lactylation in AD patients and AD model mice and cells. Proteomic mass spectrometry analysis further identified lysine 612 (APP-K612la) as a crucial site for APP lactylation, influencing APP amyloidogenic processing. A lactyl-mimicking mutant (APP, ) reduced amyloid-B peptide (Ap) generation and slowed down K612T cognitive deficits in vivo. Mechanistically, APP eur appeared to facilitate APP trafficking and metabolism. However, lactylated APP entering the endosome inhibited its binding to BACE1, suppressing subsequent cleavage. Instead, it promoted protein interaction between APP and CD2-associated protein (CD2AP), thereby accelerating the endosomal-lysosomal degradation pathway of APP. In the APP23/PS45 double-transgenic mouse model of AD, APP-Kla was susceptible to L-lactate regulation, which reduced Ap pathology and repaired spatial learning and memory deficits. Thus, these findings suggest that targeting APP lactylation may be a promising therapeutic strategy for AD in humans.

Neuronal death triggered by hypoxia-ischemia (HI) is a major cause of neonatal mortality and long-term neurological deficits. Excessive autophagy plays a pathogenic role in neonatal hypoxic-ischemic encephalopathy (HIE), and inhibition of phosphatase and tensin homolog deleted on chromosome TEN (PTEN) nuclear translocation has been shown to suppress autophagy. Our recent study demonstrated that blocking PTEN nuclear import with the peptide Tat-K13 mitigates HI-induced behavioral impairments. However, the underlying mechanism remains unclear. Here, we found that HI activated the p-JUN–SESN2–AMPK signaling pathway in both in vivo and in vitro models of neonatal hypoxic-ischemic brain damage (HIBD). Downregulation of JUN reduced neuronal loss and improved behavioral outcomes in HIBD rats. Furthermore, Tat-K13-mediated blockade of PTEN nuclear translocation attenuated HI-induced activation of the p-JUN–SESN2–AMPK pathway and suppressed autophagy. Notably, the neuroprotective and behavioral benefits conferred by Tat-K13 were achieved through autophagy inhibition resulting from suppression of this signaling cascade. These findings identify targeting PTEN nuclear import with Tat-K13 as a potential therapeutic strategy for neonatal HIE, acting via the p-JUN–SESN2–AMPK-autophagy axis to promote neuronal survival and functional recovery.

Mitogen-activated protein kinase (MAPK) phosphatase 1 (MKP-1) is an essential negative regulator of MAPKs by dephosphorylating MAPKs at both tyrosine and threonine residues. Dysregulation of the MAPK signaling pathway has been associated with Alzheimer’s disease (AD). However, the role of MKP-1 in AD pathogenesis remains elusive. Here, we report that MKP-1 levels were decreased in the brain tissues of patients with AD and an AD mouse model. The reduction in MKP-1 gene expression appeared to be a result of transcriptional inhibition via transcription factor specificity protein 1 (Sp1) cis-acting binding elements in the MKP-1 gene promoter. Amyloid-β (Aβ)-induced Sp1 activation decreased MKP-1 expression. However, upregulation of MKP-1 inhibited the expression of both Aβ precursor protein (APP) and β-site APP-cleaving enzyme 1 by inactivating the extracellular signal-regulated kinase 1/2 (ERK)/MAPK signaling pathway. Furthermore, upregulation of MKP-1 reduced Aβ production and plaque formation and improved hippocampal long-term potentiation (LTP) and cognitive deficits in APP/PS1 transgenic mice. Our results demonstrate that MKP-1 impairment facilitates the pathogenesis of AD, whereas upregulation of MKP-1 plays a neuroprotective role to reduce Alzheimer-related phenotypes. Thus, this study suggests that MKP-1 is a novel molecule for AD treatment.

The imbalance between neuronal excitation and inhibition (E/I) in neural circuit has been considered to be at the root of numerous brain disorders. We recently reported a novel feedback crosstalk between the excitatory neurotransmitter glutamate and inhibitory γ‐aminobutyric acid type A receptor (GABA A R)‐glutamate allosteric potentiation of GABA A R functions through a direct binding of glutamate to the GABA A R itself. Here, we investigated the physiological significance and pathological implications of this cross‐talk by generating the β3 E182G knock‐in (KI) mice. We found that β3 E182G KI, while had little effect on basal GABA A R‐mediated synaptic transmission, significantly reduced glutamate potentiation of GABA A R‐mediated responses. These KI mice displayed lower thresholds for noxious stimuli, higher susceptibility to seizures and enhanced hippocampus‐related learning and memory. Additionally, the KI mice exhibited impaired social interactions and decreased anxiety‐like behaviors. Importantly, hippocampal overexpression of wild‐type β3‐containing GABA A Rs was sufficient to rescue the deficits of glutamate potentiation of GABA A R‐mediated responses, hippocampus‐related behavioral abnormalities of increased epileptic susceptibility, and impaired social interactions. Our data indicate that the novel crosstalk among excitatory glutamate and inhibitory GABA A R functions as a homeostatic mechanism in fine‐tuning neuronal E/I balance, thereby playing an essential role in ensuring normal brain functioning.