Jiawei-Xiaoyao pill elicits a rapid antidepressant effect, dependent on activating CaMKII/mTOR/BDNF signaling pathway in the hippocampus.

ETHNOPHARMACOLOGICAL RELEVANCE: Jiawei-Xiaoyao pill (JWX), a traditional Chinese medicine, was recorded in ancient Chinese medicine pharmacopoeia using for treatment of various diseases, including mood disorders. Current mainstream antidepressants have a disadvantage in delayed onset of action. The rapid antidepressant potential of JWX and the underlying mechanisms remain unclear. AIM OF THE STUDY: We aimed to assess the rapid antidepressant potential of JWX, within the prescription dose range, and the distinct underlying neuroplasticity signaling mechanism. MATERIALS AND METHODS: The rapid antidepressant response of JWX were determined using various behavioral paradigms, and in a corticosterone (CORT)-induced depression model in mice. The molecular neuroplasticity signaling and the expression of BDNF in the hippocampus was evaluated using immunoblotting and immunostaining. The contribution of specific signaling was investigated using pharmacological interventions. RESULTS: A single dose of JWX induced rapid and persistent antidepressant effects in both the normal and chronic CORT-exposed mice. The phosphorylation of CaMKII, mTOR, ERK and the expressions of BDNF, synapsin1 and PSD95 increased at 30 min post JWX. JWX restored the expression of BDNF in the hippocampal dentate gyrus reduced by CORT-exposure. The rapid antidepressant effect and upregulation of BDNF expression by JWX was blunted by a mTOR antagonist, rapamycin, or a CaMKII antagonist, KN-93. CaMKII signaling blockade blunted mTOR signaling activated by JWX, but not vice versa. CONCLUSION: JWX elicits a rapid antidepressant effect, via quickly stimulating CaMKII signaling, subsequently activating mTOR-BDNF signaling pathway, and thus enhancing hippocampal neuroplasticity.

Icariin improves learning and memory function in Aß1-42-induced AD mice through regulation of the BDNF-TrκB signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Epimedium brevicornu Maxim. is a traditional medicinal Chinese herb that is enriched with flavonoids, which have remarkably high medicinal value. Icariin (ICA) is a marker compound isolated from the total flavonoids of Epimedium brevicornu Maxim. It has been shown to improve Neurodegenerative disease, therefore, ICA is probably a potential drug for treating AD. MATERIALS AND METHODS: The 6-8-week-old SPF-class male ICR mice were randomly divided into 8 groups for modeling, and then the mice were administered orally with ICA for 21 days. The behavioral experiments were conducted to evaluate if learning and memory behavior were absent in mice, confirming that infusion of Amyloid ß-protein (Aß)1-42 caused significant memory impairment. The morphological changes and damage of neurons in the mice's brains were observed by HE and Nissl staining. The spinous protrusions (dendritic spines) on neuronal dendrites were investigated by Golgi-Cox staining. The molecular mechanism of ICA was examined by Western Blot. The protein docking of ICA and Donepezil with BDNF were analyzed to determine their interaction. RESULTS: The behavioral experimental results showed that in Aß1-42-induced AD mice, the learning and memory abilities were improved after using ICA. At the same time, the low, medium, and high doses of ICA could reduce the content of Aß1-42 in the hippocampus of AD mice, repair neuronal damage, enhance synaptic plasticity, as well as increase the expression of BDNF, TrκB, CREB, Akt, GAP43, PSD95, and SYN proteins in the hippocampus of mice. However, the effect with high doses of ICA is more pronounced. The high-dose administration of ICA has the best therapeutic effect on AD mice. After administering the inhibitor k252a, the therapeutic effect of ICA was reversed. The macromolecular docking results of ICA and BDNF protein demonstrated a strong interaction of -7.8 kcal/mol, which indicates that ICA plays a therapeutic role in AD mice by regulating the BDNF-TrκB signaling pathway. CONCLUSIONS: The results confirm that ICA can repair neuronal damage, enhance synaptic plasticity, as well as ultimately improve learning and memory impairment through the regulation of the BDNF-TrκB signaling pathway.

Plasma exosomes proteome profiling discovers protein markers associated with the therapeutic effect of Chaihu-Longgu-Muli decoction on temporal lobe epilepsy.

ETHNOPHARMACOLOGICAL RELEVANCE: Traditional Chinese medicine (TCM) uses Chaihu-Longgu-Muli decoction (CLMD) to alleviate disease, clear away heat, calm the mind, and temper excitation. It has been widely used for the therapy of neuropsychiatric disorders including epilepsy, dementia, anxiety, insomnia, and depression for several centuries in China. AIM OF THE STUDY: This study aims to analyze differentially expressed proteins (DEPs) in the plasma exosomes of patients with temporal lobe epilepsy (TLE) and after the Chaihu-Longgu-Muli Decoction (CLMD) therapy and to explore the biomarkers of TLE and the potential targets of CLMD in treating TLE. MATERIALS AND METHODS: The plasma exosomes of normal people and patients with TLE before the treatment of oxcarbazepine (OXC) and combined treatment of OXC and CLMD (OXC.CLMD) were harvested. The exosomes were separated from plasma through ultracentrifugation and then identified by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and flow cytometry. The DEPs were analyzed by proteomics and then subjected to gene ontology (GO) functional enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. The protein level of key genes was detected using Western blot. A lithium chloride-pilocarpine-induced epilepsy rat model was established and treated with OXC alone, OXC. CLMD, and CLMD alone (low dose and high dose). Neuronal injury in the hippocampal dentate gyrus and ribosomal protein L6 (RPL6) expression in the brain tissues were detected using H&E staining, Nissl staining, and Western blot. RESULTS: The proteomic analysis showed several DEPs were present among plasma exosomes in the four groups; DEPs were enriched in epilepsy-related function and pathway. Four key proteins were screened, including RPL6, Nucleolin (NCL), Apolipoprotein A1 (APOA1), and Lactate Dehydrogenase A (LDHA). Among them, RPL6, NCL, and LDHA protein levels were downregulated and APOA1 protein level was upregulated in the plasma exosomes of TLE patients. After OXC and OXC. CLMD treatment, the protein level of RPL6, NCL, and LDHA was increased, and the APOA1 protein level was decreased. Moreover, the RPL6 protein level was further elevated after OXC. CLMD treatment than that after OXC treatment. In the TLE rat model, neuronal degeneration and necrosis in the hippocampal dentate gyrus increased and RPL6 expression level decreased. After the treatment with OXC, OXC. CLMD, and CLMD alone, the degeneration and necrosis of neurons decreased, and the RPL6 expression level was increased; RPL6 upregulation was remarkably obvious after CLMD treatment. CONCLUSIONS: RPL6, NCL, LDHA and APOA1 are the DEPs in the plasma exosomes of patients with TLE before and after therapy. RPL6 might be a potential biomarker of CLMD in treating TLE.

Olax subscorpioidea prevented scopolamine-induced memory impairment through the prevention of oxido-inflammatory damage and modulation of cholinergic transmission.

ETHNOPHARMACOLOGICAL RELEVANCE: Olax subscorpioidea oliv. is a shrub plant of the Olacaceae family with reported usage in ethnomedicine as a nootropic agent for the management of Alzheimer's-like dementia. AIM: The aim of this study is to investigate the nootropic potential of methanol extract of Olax subscorpioidea (MEOS) in scopolamine-induced Alzheimer's-like dementia. MATERIALS AND METHODS: Thirty male mice, assigned into six groups (n = 8), were used for this study. Group, I received distilled water, group II received scopolamine (1 mg/kg, i.p.), groups iii-v received 25, 50, and 100 mg/kg, p.o. of MEOS and scopolamine (1 mg/kg/i.p.), and group vi received donepezil 5 mg/kg, p.o.and scopolamine (1 mg/kg, i.p.). The animals were pre-treated with MEOS and Donepezil for 14 days, and scopolamine from the 8th to 14th day. Followed by cognitive, oxidative stress, neuroinflammation, and histology assessments. RESULTS: 100 mg/kg MEOS significantly reduced transfer latency and increased discrimination index in the elevated plus maze and novel object recognition test cognitive assessments. 100 mg/kg MEOS, significantly reduced oxidative stress, protect endogenous antioxidants, suppressed neuroinflammation, and acetylcholinesterase (ACHE) activity. The histomorphometry study of the hippocampus revealed that MEOS prevented extensive pyknosis, karyolysis, chromatolysis, and loss of hippocampal neurons that accompanied scopolamine treatment. CONCLUSION: MEOS protected against Alzheimer's-like dementia via the suppression of neuroinflammation and oxidative stress associated with scopolamine-induced amnesic behavior.

Antidepressant effect of Perilla frutescens essential oil through monoamine neurotransmitters and BDNF/TrkB signal pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Traditional Chinese medicine posits that affect-mind ill-being is the primary cause of depression, with Qi movement stagnation as its pathogenesis. As such, clinical treatment for depression should prioritize regulating Qi and relieving depressive symptoms. The pharmacological properties of traditional Chinese medicine indicate that Perilla frutescens may have potential therapeutic effects on depression and other neuropsychiatric diseases due to its ability to regulate Qi and alleviate depressive symptoms. Although previous studies have reported the antidepressant effects of Perilla frutescens, the mechanism underlying PFEO inhalation-mediated antidepressant effect remains unclear. AIM OF THE STUDY: The aim of this investigation is to elucidate the antidepressant mechanisms of PFEO by examining its effects on monoamine neurotransmitters and the BDNF/TrkB signaling pathway. MATERIALS AND METHODS: The CUMS rat model of depression was established, and the depressive state of the animals was assessed through sucrose preference and forced swim tests. ELISA assays were conducted to determine monoamine neurotransmitter levels in the hippocampus and cerebral cortex of rats. Immunohistochemistry, western blotting, and RT-PCR experiments were employed to investigate the BDNF/TrkB signaling pathway's regulation of depression via PFEO inhalation. RESULTS: It has been observed that inhalation administration of PFEO can significantly enhance the preference for sugar water in CUMS rats and reduce their immobility time during forced swimming. Additionally, there was an increase in the levels of monoamine transmitters in both the hippocampus and cerebral cortex of these rats. Furthermore, there was an upregulation in the expression levels of BDNF and TrkB positive cells as well as BDNF and TrkB proteins within both regions, along with increased BDNF mRNA and TrkB mRNA expression levels. CONCLUSION: The antidepressant effect of PFEO via inhalation administration is speculated to be mediated through the monoamine neurotransmitters and BDNF/TrkB signaling pathway.

Hippocampal Inflammation and Gene Expression Changes in Peripheral Lipopolysaccharide Challenged Mice Showing Sickness and Anxiety-Like Behaviors.

Neuroinflammation is often associated with the development of depressive and anxiety disorders. The hippocampus is one of the brain regions affected by inflammation that is associated with these symptoms. However, the mechanism of hippocampal inflammation-induced emotional behavior remains unknown. The aim of this study was to clarify temporal changes in the neuroinflammatory responses in the hippocampus and the response of dentate gyrus (DG) neurons using peripheral lipopolysaccharide (LPS)-challenged mice. LPS administration induced anxiety-like activity in the elevated plus maze test and social interaction test after 24 h, at which time the mice had recovered from sickness behavior. We examined the hippocampal inflammation-related gene expression changes over time. The expression of interleukin-1ß (Il1b) and tumor necrosis factor α (Tnfa) was rapidly enhanced and sustained until 24 h after LPS administration, whereas the expression of Il6 was transiently induced at approx. 6 h. IL-6-dependent downstream signaling of transducer and activator of transcription 3 (STAT3) was also activated approx. 3-6 h after LPS treatment. The expression of innate immune genes including interferon-induced transmembrane proteins such as interferon-induced transmembrane protein 1 (Ifitm1) and Ifitm3 and complement factors such as C1qa and C1qb started to increase approx. 6 h and showed sustained or further increase at 24 h. We also examined changes in the expression of several maturation markers in the DG and found that LPS enhanced the expression of calbindin 1 (Calb1), tryptophan-2,3-dioxigenase 2 (Tdo2), Il1rl, and neurotrophin-3 (Ntf3) at 24 h after LPS treatment. Collectively, these results demonstrate temporal changes of inflammation and gene expression in the hippocampus in LPS-induced sickness and anxiety-like behaviors.

[Long-term high-fat diet's impact on synaptic plasticity in the visual cortex and hippocampus neurons: an experimental study].

Objective: To investigate the effects and mechanisms of long-term high-fat diet on synaptic plasticity in the visual cortex and hippocampus neurons of juvenile mice. Methods: This was an experimental study. Twenty-four 4-week-old male C57BL/6J mice were randomly divided into two groups, using a randomized numerical table, with 12 mice in each group. The ND group was fed a normal diet, while the HFD group was fed a high-fat diet. After 12 weeks of feeding, mouse body weight, body fat percentage, glucose tolerance, and blood lipid levels were recorded. Six mice from each group were randomly selected using a randomized numerical table, and long-term potentiation (LTP) in the lateral geniculate nucleus (LGN)-primary visual cortex binocular zone (V1B area) and hippocampus CA3-CA1 were recorded in vitro. Field excitatory postsynaptic potentials (fEPSPs) were measured, and the normalized fEPSP slope was calculated to evaluate changes in cortical synaptic plasticity. Subsequently, brain tissue was collected for Golgi staining to observe the development of pyramidal neurons in layers Ⅱ-Ⅲ of the primary visual cortex and CA1 region of the hippocampus, and changes in dendritic spine morphology and quantity were compared. The remaining six mice from each group were euthanized, and brain tissue was collected for transmission electron microscopy to observe ultrastructural changes in the visual cortex V1B area and hippocampus CA1 region neurons. Independent samples t-test was used for statistical analysis. Results: After 12 weeks of feeding, the body weight of mice in the HFD group was (29.17±1.63) g, significantly lower than the ND group which was (37.99±6.87) g (t=4.33, P<0.001). The body fat percentage in the HFD group was 1.09%±0.22%, which was higher than the ND group with 0.85%±0.09% (t=2.50, P=0.032). HFD mice showed a significant increase in blood glucose level 30 minutes after glucose injection, reaching (17.80±3.94) mmol/L, compared to the ND group with (23.10±1.48) mmol/L (t=3.07, P=0.013). At 60 minutes after glucose injection, the difference in blood glucose levels between the ND group [(13.58±2.39) mmol/L] and the HFD group [(23.70±3.56) mmol/L] was statistically significant (t=5.40, P<0.001). Subsequently, both groups showed a decline in blood glucose levels, and at 120 minutes after glucose injection, the blood glucose level in the ND group decreased to (8.50±1.05) mmol/L, while the HFD group remained at a higher level of (16.03±4.17) mmol/L, showing a statistically significant difference (t=3.91, P=0.004). The serum total cholesterol levels in the ND and HFD groups were (4.08±0.35) mmol/L and (10.80±0.90) mmol/L, respectively, with the HFD group higher than the ND group (t=15.23, P<0.001). However, there was no significant difference in triglyceride levels (P>0.05). The high-density lipoprotein cholesterol level in the ND group was (2.12±0.57) mmol/L, while in the HFD group, it was (1.28±0.15) mmol/L, with the HFD group lower than the ND group (t=3.15, P=0.014). Non-high-density lipoprotein cholesterol level in the HFD group was (11.06±1.46) mmol/L, significantly higher than the ND group with (2.28±0.43) mmol/L (t=12.88, P<0.001). In the hippocampal CA3-CA1 pathway, the fEPSP slope increased by 239.1%±88.8% of baseline in the ND group, while in the HFD group, it was only 147.6%±31.6% of baseline, indicating lower LTP compared to the ND group (t=7.20, P<0.001). For the LGN-V1 pathway, the fEPSP slope increased by 204.8%±67.0% of baseline in the ND group, while in the HFD group, it was 121.1%±15.7% of baseline, showing reduced LTP compared to the ND group (t=9.11, P<0.001). Regarding the visual cortex, in the V1B area of the ND group, the number of dendritic spines per 10 µm was (1.31±1.14), while in the HFD group, it was (0.77±0.43), demonstrating a significant decrease in dendritic spine density (t=3.45, P<0.001). The proportion of mature dendritic spines in the ND group was 69.98%, while non-mature dendritic spines accounted for 30.02%. In contrast, the HFD group had 45.76% mature dendritic spines and 54.24% non-mature dendritic spines. Regarding changes in hippocampal CA1 pyramidal neurons, the cell bodies and axons were not damaged, but HFD group neurons exhibited simplified dendritic structures with reduced branching. The number of dendritic spines per 10 µm was (10.25±3.84) in the HFD group and (25.22±8.21) in the ND group, indicating significantly lower dendritic spine density in the HFD group (t=12.42, P<0.001). The proportion of mature dendritic spines in the ND group was 70.88%, while non-mature dendritic spines accounted for 29.12%. In contrast, the HFD group had 47.37% mature dendritic spines and 52.63% non-mature dendritic spines. Moreover, the ultrastructure of neurons in the visual cortex V1B area and hippocampus CA1 region of HFD mice showed evident damage, with disrupted cell structures, swollen and vacuolated mitochondria, reduced or even disappeared mitochondrial cristae, and decreased synaptic quantity with damaged structure. Conclusions: Long-term high-fat diet in juvenile mice leads to abnormal development and functional maturation of synapses in the visual cortex and hippocampal regions. Dendrites, as the foundation of synaptic structures, undergo abnormal development, which can cause alterations in synaptic plasticity of related neural circuits.

A critical role for CaMKII in behavioral timescale synaptic plasticity in hippocampal CA1 pyramidal neurons.

Behavioral timescale synaptic plasticity (BTSP) is a type of non-Hebbian synaptic plasticity reported to underlie place field formation. Despite this important function, the molecular mechanisms underlying BTSP are poorly understood. The α-calcium-calmodulin-dependent protein kinase II (αCaMKII) is activated by synaptic transmission-mediated calcium influx, and its subsequent phosphorylation is central to synaptic plasticity. Because the activity of αCaMKII is known to outlast the event triggering phosphorylation, we hypothesized that it could mediate the extended timescale of BTSP. To examine the role of αCaMKII in BTSP, we performed whole-cell in vivo and in vitro recordings in CA1 pyramidal neurons from mice engineered with a point mutation at the autophosphorylation site (T286A) causing accelerated signaling kinetics. Here, we demonstrate a profound deficit in synaptic plasticity, strongly suggesting that αCaMKII signaling is required for BTSP. This study elucidates part of the molecular mechanism of BTSP and provides insight into the function of αCaMKII in place cell formation and ultimately learning and memory.

Novel Psychopharmacological Herbs Relieve Behavioral Abnormalities and Hippocampal Dysfunctions in an Animal Model of Post-Traumatic Stress Disorder.

Post-traumatic stress disorder (PTSD) is an anxiety disorder caused by traumatic or frightening events, with intensified anxiety, fear memories, and cognitive impairment caused by a dysfunctional hippocampus. Owing to its complex phenotype, currently prescribed treatments for PTSD are limited. This study investigated the psychopharmacological effects of novel COMBINATION herbal medicines on the hippocampus of a PTSD murine model induced by combining single prolonged stress (SPS) and foot shock (FS). We designed a novel herbal formula extract (HFE) from Chaenomeles sinensis, Glycyrrhiza uralensis, and Atractylodes macrocephala. SPS+FS mice were administered HFE (500 and 1000 mg/kg) once daily for 14 days. The effects of HFE of HFE on the hippocampus were analyzed using behavioral tests, immunostaining, Golgi staining, and Western blotting. HFE alleviated anxiety-like behavior and fear response, improved short-term memory, and restored hippocampal dysfunction, including hippocampal neurogenesis alteration and aberrant migration and hyperactivation of dentate granule cells in SPS+FS mice. HFE increased phosphorylation of the Kv4.2 potassium channel, extracellular signal-regulated kinase, and cAMP response element-binding protein, which were reduced in the hippocampus of SPS+FS mice. Therefore, our study suggests HFE as a potential therapeutic drug for PTSD by improving behavioral impairment and hippocampal dysfunction and regulating Kv4.2 potassium channel-related pathways in the hippocampus.

Abnormal accumulation of extracellular vesicles in hippocampal dystrophic axons and regulation by the primary cilia in Alzheimer's disease.

Dystrophic neurites (DNs) are abnormal axons and dendrites that are swollen or deformed in various neuropathological conditions. In Alzheimer's disease (AD), DNs play a crucial role in impairing neuronal communication and function, and they may also contribute to the accumulation and spread of amyloid beta (Aß) in the brain of AD patients. However, it is still a challenge to understand the DNs of specific neurons that are vulnerable to Aß in the pathogenesis of AD. To shed light on the development of radiating DNs, we examined enriched dystrophic hippocampal axons in a mouse model of AD using a three-dimensional rendering of projecting neurons. We employed the anterograde spread of adeno-associated virus (AAV)1 and conducted proteomic analysis of synaptic compartments obtained from hippocampo-septal regions. Our findings revealed that DNs were formed due to synaptic loss at the axon terminals caused by the accumulation of extracellular vesicle (EV). Abnormal EV-mediated transport and exocytosis were identified in association with primary cilia, indicating their involvement in the accumulation of EVs at presynaptic terminals. To further address the regulation of DNs by primary cilia, we conducted knockdown of the Ift88 gene in hippocampal neurons, which impaired EV-mediated secretion of Aß and promoted accumulation of axonal spheroids. Using single-cell RNA sequencing, we identified the septal projecting hippocampal somatostatin neurons (SOM) as selectively vulnerable to Aß with primary cilia dysfunction and vesicle accumulation. Our study suggests that DNs in AD are initiated by the ectopic accumulation of EVs at the neuronal axon terminals, which is affected by neuronal primary cilia.

Neuroprotection against Aluminum Chloride-Induced Hippocampus Damage in Albino Wistar Rats by Leucophyllum frutescens (Berl.) I.M. Johnst. Leaf Extracts: A Detailed Insight into Phytochemical Analysis and Antioxidant and Enzyme Inhibition Assays.

BACKGROUND: A previously unstudied medicinal plant, Leucophyllum frutescens (Berland.) I.M. Johnst. (Scrophulariaceae) was investigated to evaluate its potential in preventing and treating neurodegenerative diseases, including Alzheimer's disease. METHODS: Methanolic leaf extract (MELE) and its fractions (HELE, CHLE, and BULE) were evaluated for their polyphenolic content and antioxidant activity by five different methods, including in vitro enzyme inhibition assays, which are clinically linked to neurodegenerative diseases. The potentially active n-butanol fraction (BULE) was further evaluated for its neuroprotective effects using an albino rat animal model and phytoconstituents profiling using Liquid chromatography with tandem mass spectrometry (LC-MS/MS), and in silico molecular docking by Maestro® Schrödinger. RESULTS: The n-butanol fraction (BULE) in the hydroalcoholic leaf extract exhibited the highest total phenolic content (230.435 ± 1.575 mg gallic acid equivalent gm-1± SD). The chloroform leaf extract exhibited the highest total flavonoid content (293.343 ± 3.756 mg quercetin equivalent gm-1± SD) as well as the highest antioxidant content, which was equivalent to Trolox, with five assay methods. Similarly, the chloroform and n-butanol fractions from the hydroalcoholic leaf extract significantly inhibited human acetylcholinesterase and butyrylcholinesterase with their IC50 values of 12.14 ± 0.85 and 129.73 ± 1.14 µg∙mL-1, respectively. The in vivo study revealed that BULE exhibited a significant neuroprotective effect at doses of 200 and 400 mg/kg/day in an aluminum chloride-induced neurodegenerative albino rat model. The LC-MS/MS analysis of BULE tentatively confirmed the presence of biologically active secondary metabolites, such as theobromine, propyl gallate, quercetin-3-O-glucoside, myricetin-3-acetylrhamnoside, isoquercitrin-6'-O-malonate, diosmetin-7-O-glucuronide-3'-O-pentose, pinoresinol diglucoside, asarinin, eridictoyl, epigallocatechin, methyl gallate derivative, and eudesmin. The results from the computational molecular docking of the identified secondary metabolites revealed that diosmetin-7-O-glucuronide-3'-O-pentose had the highest binding affinity to human butyrylcholinesterase, while isoquercetin-6'-O-malonate had the highest to human acetylcholinesterase, and pinoresinol diglucoside to human salivary alpha-amylase. CONCLUSIONS: The present study concluded a need for further exploration into this medicinal plant, including the isolation of the bioactive compounds responsible for its neuroprotective effects.

GSDMD gene knockout alleviates hyperoxia-induced hippocampal brain injury in neonatal mice.

BACKGROUND: Neonatal hyperoxia exposure is associated with brain injury and poor neurodevelopment outcomes in preterm infants. Our previous studies in neonatal rodent models have shown that hyperoxia stimulates the brain's inflammasome pathway, leading to the activation of gasdermin D (GSDMD), a key executor of pyroptotic inflammatory cell death. Moreover, we found pharmacological inhibition of caspase-1, which blocks GSDMD activation, attenuates hyperoxia-induced brain injury in neonatal mice. We hypothesized that GSDMD plays a pathogenic role in hyperoxia-induced neonatal brain injury and that GSDMD gene knockout (KO) will alleviate hyperoxia-induced brain injury. METHODS: Newborn GSDMD knockout mice and their wildtype (WT) littermates were randomized within 24 h after birth to be exposed to room air or hyperoxia (85% O2) from postnatal days 1 to 14. Hippocampal brain inflammatory injury was assessed in brain sections by immunohistology for allograft inflammatory factor 1 (AIF1) and CD68, markers of microglial activation. Cell proliferation was evaluated by Ki-67 staining, and cell death was determined by TUNEL assay. RNA sequencing of the hippocampus was performed to identify the transcriptional effects of hyperoxia and GSDMD-KO, and qRT-PCR was performed to confirm some of the significantly regulated genes. RESULTS: Hyperoxia-exposed WT mice had increased microglia consistent with activation, which was associated with decreased cell proliferation and increased cell death in the hippocampal area. Conversely, hyperoxia-exposed GSDMD-KO mice exhibited considerable resistance to hyperoxia as O2 exposure did not increase AIF1 + , CD68 + , or TUNEL + cell numbers or decrease cell proliferation. Hyperoxia exposure differentially regulated 258 genes in WT and only 16 in GSDMD-KO mice compared to room air-exposed WT and GSDMD-KO, respectively. Gene set enrichment analysis showed that in the WT brain, hyperoxia differentially regulated genes associated with neuronal and vascular development and differentiation, axonogenesis, glial cell differentiation, hypoxia-induced factor 1 pathway, and neuronal growth factor pathways. These changes were prevented by GSDMD-KO. CONCLUSIONS: GSDMD-KO alleviates hyperoxia-induced inflammatory injury, cell survival and death, and alterations of transcriptional gene expression of pathways involved in neuronal growth, development, and differentiation in the hippocampus of neonatal mice. This suggests that GSDMD plays a pathogenic role in preterm brain injury, and targeting GSDMD may be beneficial in preventing and treating brain injury and poor neurodevelopmental outcomes in preterm infants.

Dual Modulator of ASIC Channels and GABAA Receptors from Thyme Alters Fear-Related Hippocampal Activity.

Acid-sensing ion channels (ASICs) are proton-gated ion channels that mediate nociception in the peripheral nervous system and contribute to fear and learning in the central nervous system. Sevanol was reported previously as a naturally-occurring ASIC inhibitor from thyme with favorable analgesic and anti-inflammatory activity. Using electrophysiological methods, we found that in the high micromolar range, the compound effectively inhibited homomeric ASIC1a and, in sub- and low-micromolar ranges, positively modulated the currents of α1ß2γ2 GABAA receptors. Next, we tested the compound in anxiety-related behavior models using a targeted delivery into the hippocampus with parallel electroencephalographic measurements. In the open field, 6 µM sevanol reduced both locomotor and θ-rhythmic activity similar to GABA, suggesting a primary action on the GABAergic system. At 300 µM, sevanol markedly suppressed passive avoidance behavior, implying alterations in conditioned fear memory. The observed effects could be linked to distinct mechanisms involving GABAAR and ASIC1a. These results elaborate the preclinical profile of sevanol as a candidate for drug development and support the role of ASIC channels in fear-related functions of the hippocampus.

Proteome profiling of hippocampus reveals the neuroprotective effect of mild hypothermia on global cerebral ischemia-reperfusion injury in rats.

Cerebral ischemia is one of the leading causes of disability and mortality worldwide. Blood reperfusion of ischemic cerebral tissue may cause cerebral ischemia-reperfusion (IR) injury. In this study, a rat model of global cerebral I/R injury was established via Pulsinelli's four-vessel occlusion (4-VO) method. The liquid chromatography-tandem mass spectrometry (LC-MS/MS) and bioinformatics analysis were employed to examine the ipsilateral hippocampus proteome profiles of rats with/without MH (32 °C) treatment after IR injury. Totally 2 122 proteins were identified, among which 153 proteins were significantly changed associated with MH (n = 7 per group, fold change-1.5, p < 0.05). GO annotation of the differentially expressed proteins (DEPs) revealed that cellular oxidant detoxification, response to zinc ions, aging, oxygen transport, negative regulation of catalytic activity, response to hypoxia, regulation of protein phosphorylation, and cellular response to vascular endothelial growth factor stimulus were significantly enriched with MH treatment. The KEGG analysis indicated that metabolic pathways, thermogenesis, pathways of neurodegeneration, chemical carcinogenesis-reactive oxygen species, fluid shear stress and atherosclerosis, and protein processing in endoplasmic reticulum were significantly enriched with MH treatment. Importantly, changes in 16 DEPs were reversed by MH treatment. Among them, VCAM-1, S100A8, CaMKK2 and MKK7 were verified as potential markers associated with MH neuroprotection by Western blot analysis. This study is one of the first to investigate the neuroprotective effects of MH on the hippocampal proteome of experimental models of cerebral IR injury. These DEPs may be involved in the most fundamental molecular mechanisms of MH neuroprotection, and provide a scientific foundation for further promotion of reparative strategies in cerebral IR injury.

From genetic correlations of Alzheimer's disease to classification with artificial neural network models.

Sporadic Alzheimer's disease (AD) is a complex neurological disorder characterized by many risk loci with potential associations with different traits and diseases. AD, characterized by a progressive loss of neuronal functions, manifests with different symptoms such as decline in memory, movement, coordination, and speech. The mechanisms underlying the onset of AD are not always fully understood, but involve a multiplicity of factors. Early diagnosis of AD plays a central role as it can offer the possibility of early treatment, which can slow disease progression. Currently, the methods of diagnosis are cognitive testing, neuroimaging, or cerebrospinal fluid analysis that can be time-consuming, expensive, invasive, and not always accurate. In the present study, we performed a genetic correlation analysis using genome-wide association statistics from a large study of AD and UK Biobank, to examine the association of AD with other human traits and disorders. In addition, since hippocampus, a part of cerebral cortex could play a central role in several traits that are associated with AD; we analyzed the gene expression profiles of hippocampus of AD patients applying 4 different artificial neural network models. We found 65 traits correlated with AD grouped into 9 clusters: medical conditions, fluid intelligence, education, anthropometric measures, employment status, activity, diet, lifestyle, and sexuality. The comparison of different 4 neural network models along with feature selection methods on 5 Alzheimer's gene expression datasets showed that the simple basic neural network model obtains a better performance (66% of accuracy) than other more complex methods with dropout and weight regularization of the network.

Differential Epigenetic Changes in the Dorsal Hippocampus of Male and Female SAMP8 Mice: A Preliminary Study.

Alzheimer's disease (AD) is the most common age-related neurodegenerative disease characterized by memory loss and cognitive impairment. The causes of the disease are not well understood, as it involves a complex interaction between genetic, environmental, and epigenetic factors. SAMP8 mice have been proposed as a model for studying late-onset AD, since they show age-related learning and memory deficits as well as several features of AD pathogenesis. Epigenetic changes have been described in SAMP8 mice, although sex differences have never been evaluated. Here we used western blot and qPCR analyses to investigate whether epigenetic markers are differentially altered in the dorsal hippocampus, a region important for the regulation of learning and memory, of 9-month-old male and female SAMP8 mice. We found that H3Ac was selectively reduced in male SAMP8 mice compared to male SAMR1 control mice, but not in female mice, whereas H3K27me3 was reduced overall in SAMP8 mice. Moreover, the levels of HDAC2 and JmjD3 were increased, whereas the levels of HDAC4 and Dnmt3a were reduced in SAMP8 mice compared to SAMR1. In addition, levels of HDAC1 were reduced, whereas Utx and Jmjd3 were selectively increased in females compared to males. Although our results are preliminary, they suggest that epigenetic mechanisms in the dorsal hippocampus are differentially regulated in male and female SAMP8 mice.

Dorsal-Ventral Gradient of Activin Regulates Strength of GABAergic Inhibition along Longitudinal Axis of Mouse Hippocampus in an Activity-Dependent Fashion.

The functional and neurophysiological distinction between the dorsal and ventral hippocampus affects also GABAergic inhibition. In line with this notion, ventral CA1 pyramidal cells displayed a more dynamic and effective response to inhibitory input compared to their dorsal counterparts. We posit that this difference is effected by the dorsal-ventral gradient of activin A, a member of the transforming growth factor-ß family, which is increasingly recognized for its modulatory role in brain regions involved in cognitive functions and affective behavior. Lending credence to this hypothesis, we found that in slices from transgenic mice expressing a dominant-negative mutant of activin receptor IB (dnActRIB), inhibitory transmission was enhanced only in CA1 neurons of the dorsal hippocampus, where the basal activin A level is much higher than in the ventral hippocampus. We next asked how a rise in endogenous activin A would affect GABAergic inhibition along the longitudinal axis of the hippocampus. We performed ex vivo recordings in wild-type and dnActRIB mice after overnight exposure to an enriched environment (EE), which engenders a robust increase in activin A levels in both dorsal and ventral hippocampi. Compared to control mice from standard cages, the behaviorally induced surge in activin A produced a decline in ventral inhibition, an effect that was absent in slices from dnActRIB mice. Underscoring the essential role of activin in the EE-associated modulation of ventral inhibition, this effect was mimicked by acute application of recombinant activin A in control slices. In summary, both genetic and behavioral manipulations of activin receptor signaling affected the dorsal-ventral difference in synaptic inhibition, suggesting that activin A regulates the strength of GABAergic inhibition in a region-specific fashion.

Altered Expression of Autophagy Biomarkers in Hippocampal Neurons in a Multiple Sclerosis Animal Model.

Multiple Sclerosis (MS) is a chronic inflammatory disease that affects the brain and spinal cord. Inflammation, demyelination, synaptic alteration, and neuronal loss are hallmarks detectable in MS. Experimental autoimmune encephalomyelitis (EAE) is an animal model widely used to study pathogenic aspects of MS. Autophagy is a process that maintains cell homeostasis by removing abnormal organelles and damaged proteins and is involved both in protective and detrimental effects that have been seen in a variety of human diseases, such as cancer, neurodegenerative diseases, inflammation, and metabolic disorders. This study is aimed at investigating the autophagy signaling pathway through the analysis of the main autophagic proteins including Beclin-1, microtubule-associated protein light chain (LC3, autophagosome marker), and p62 also called sequestosome1 (SQSTM1, substrate of autophagy-mediated degradation) in the hippocampus of EAE-affected mice. The expression levels of Beclin-1, LC3, and p62 and the Akt/mTOR pathway were examined by Western blot experiments. In EAE mice, compared to control animals, significant reductions of expression levels were detectable for Beclin-1 and LC3 II (indicating the reduction of autophagosomes), and p62 (suggesting that autophagic flux increased). In parallel, molecular analysis detected the deregulation of the Akt/mTOR signaling. Immunofluorescence double-labeling images showed co-localization of NeuN (neuronal nuclear marker) and Beclin-1, LC3, and p62 throughout the CA1 and CA3 hippocampal subfields. Taken together, these data demonstrate that activation of autophagy occurs in the neurons of the hippocampus in this experimental model.

Decreased Hippocampal Neurogenesis in Aged Male Wistar Rats Is Not Associated with Memory Acquisition in a Water Maze.

Brain aging is associated with a progressive decrease in learning abilities, memory, attention, decision making, and sensory perception. Age-related cognitive disturbances may be related to a decrease in the functional capacities of the hippocampus. This brain region is essential for learning and memory, and the lifelong neurogenesis occurring in the subgranular zone of the dentate gyrus may be a key event mediating the mnemonic functions of the hippocampus. In the present study, we investigated whether age-related changes in hippocampal neurogenesis are associated with learning and memory disturbances. Four- and 24-month-old rats were trained to find a hidden platform in a water maze. Though the older group showed higher latency to search the platform as compared to the younger group, both groups learned the task. However, the density of proliferating (PCNA-positive), differentiating (Dcx-positive), and new neurons (pre-labeled BrdU-positive) was significantly lower in the hippocampus of aged rats as compared to young ones. This inhibition of neurogenesis could be related to increased local production of nitric oxide since the density of neurons expressing neuronal NO-synthase was higher in the aged hippocampus. Thus, we can suggest that an age-related decrease in neurogenesis is not directly associated with place learning in aged rats.

Age of epilepsy onset as modulating factor for naming deficit after epilepsy surgery: a voxel-based lesion-symptom mapping study.

Age at onset of epilepsy is an important predictor of deterioration in naming ability following epilepsy surgery. In 141 patients with left hemispheric epilepsy and language dominance who received epilepsy surgery at the Epilepsy Centre Erlangen, naming of objects (Boston naming test, BNT) was assessed preoperatively and 6 months postoperatively. Surgical lesions were plotted on postoperative MRI and normalized for statistical analysis using voxel-based lesion-symptom mapping (VBLSM). The correlation between lesion and presence of postoperative naming deterioration was examined varying the considered age range of epilepsy onsets. The VBLSM analysis showed that volumes of cortex areas in the left temporal lobe, which were associated with postoperative decline of naming, increased with each year of later epilepsy onset. In patients with later onset, an increasing left posterior temporobasal area was significantly associated with a postoperative deficit when included in the resection. For late epilepsy onset, the temporomesial expansion also included the left hippocampus. The results underline that early onset of epilepsy is a good prognostic factor for unchanged postoperative naming ability following epilepsy surgery. For later age of epilepsy onset, the extent of the area at risk of postoperative naming deficit at 6 months after surgery included an increasing left temporobasal area which finally also comprised the hippocampus.