Location analysis of presynaptically active and silent synapses in single-cultured hippocampal neurons.

A morphologically present but non-functioning synapse is termed a silent synapse. Silent synapses are categorized into "postsynaptically silent synapses," where AMPA receptors are either absent or non-functional, and "presynaptically silent synapses," where neurotransmitters cannot be released from nerve terminals. The presence of presynaptically silent synapses remains enigmatic, and their physiological significance is highly intriguing. In this study, we examined the distribution and developmental changes of presynaptically active and silent synapses in individual neurons. Our findings show a gradual increase in the number of excitatory synapses, along with a corresponding decrease in the percentage of presynaptically silent synapses during neuronal development. To pinpoint the distribution of presynaptically active and silent synapses, i.e., their positional information, we employed Sholl analysis. Our results indicate that the distribution of presynaptically silent synapses within a single neuron does not exhibit a distinct pattern during synapse development in different distance from the cell body. However, irrespective of neuronal development, the proportion of presynaptically silent synapses tends to rise as the projection site moves farther from the cell body, suggesting that synapses near the cell body may exhibit higher synaptic transmission efficiency. This study represents the first observation of changes in the distribution of presynaptically active and silent synapses within a single neuron.

Kamikihito reduces ß-amyloid25-35-induced axon damage via neurotrophic factors.

The Japanese herbal medicine kamikihito (KKT) is widely used for insomnia, anorexia, anemia, and depression. Recently, the efficacy of KKT against Alzheimer's disease (AD) has been demonstrated in clinical and non-clinical studies. To address the mechanism underlying the effect of KKT on AD, we examined the effects of KKT in ß-amyloid (Aß)25-35-exposed primary cultured neurons. The effects of KKT on Aß25-35-induced neurotoxicity were assessed by immunocytochemical assays and Sholl analysis of neurites, and the influence of KKT on neurotrophic factor (NF) gene expression was examined using RT-PCR analysis. As a result, Aß25-35 exposure attenuated the arborization of neurites of single cultured hippocampal neurons, and KKT treatment for 3 days ameliorated the Aß25-35-induced impairment of tau-positive axon outgrowth. This ameliorative effect of KKT was largely abolished by the Trk inhibitor K252a, and expression of NFs, nerve growth factor (Ngf), brain-derived neurotrophic factor (Bdnf), neurotrophin-3 (NT-3) was significantly increased by KKT. These results indicate that KKT ameliorates axonal atrophy via NFs signaling, providing a mechanistic basis for treatment of AD with KKT.

Differences in the incidence of obstetric complications depending on the extent and location of adenomyosis lesions.

OBJECTIVES: Although adenomyosis is reportedly associated with adverse pregnancy outcomes, clinical factors related to the high risk of obstetric complications are unclear. This study aimed to elucidate the characteristics of adenomyosis lesions associated with the increased incidence of obstetric complications based on imaging findings. METHODS: This was a retrospective, observational cohort study conducted in a tertiary perinatal care center. Eighty-eight singleton pregnant women with adenomyosis were included in the study. Based on magnetic resonance imaging or ultrasonography before and/or during pregnancy, patients were classified according to three types of image characteristics: the extent of adenomyosis lesion (focal type or diffuse type), location of the lesion (extrinsic type, intrinsic type, or indeterminate type), the positional relationship between the lesion and the placenta (placenta distant from adenomyosis or placenta over adenomyosis), and the incidence of obstetric complications were examined. RESULTS: Patients with diffuse type adenomyosis are significantly more likely to have spontaneous second-trimester miscarriage (diffuse type vs. focal type: 16.7 vs. 0%, p < .01), preterm premature rupture of membranes (19.4 vs. 1.9%, p < .01), and preeclampsia (25.0 vs. 7.7%, p = .02), as compared to those with focal type adenomyosis. In a comparison of the three location types, the incidence of placental malposition was higher in patients with the extrinsic type adenomyosis (extrinsic type vs. intrinsic type vs. indeterminate type: 20.0 vs. 6.7 vs. 2.3%, p = .03). Comparisons between the types of the placenta over or distant from adenomyosis lesion displayed no significant differences in the frequencies of obstetric complications. CONCLUSIONS: We demonstrated that the frequency of obstetric complications related to adenomyosis varies depending on the extent and location of the lesion; patients with diffuse type adenomyosis have an increased risk of spontaneous second-trimester miscarriage, preterm premature rupture of membranes, and preeclampsia, while patients with extrinsic type adenomyosis have an increased risk of placental malposition. Imaging evaluation of adenomyosis prior to conception or early in pregnancy may be useful for the obstetrical risk assessment among patients with adenomyosis.

The Effects of Ninjinyoeito on Impaired Spatial Memory and Prefrontal Cortical Synaptic Plasticity through α-Amino-3-hydroxy-5-4-isoxazole Propionic Acid Receptor Subunit in a Rat Model with Cerebral Ischemia and ß-Amyloid Injection.

Ninjinyoeito (NYT), a traditional Japanese medicine, is effective for improving physical strength and treating fatigue and anorexia. Recently, a clinical report revealed that NYT ameliorates cognitive dysfunction in Alzheimer's disease (AD) patients, although the mechanisms remain unclear. AD is a neurodegenerative disorder accompanied by a progressive deficit in memory. Current therapeutic agents are largely ineffective in treating cognitive dysfunction in AD patients. In this study, we investigated the effects of NYT on spatial memory impairment in a rat model of dementia. Rats were prepared with transient cerebral ischemia and intraventricular injection of ß-amyloid1-42 for 7 days (CI + Aß). NYT was orally administered for 7 days after cerebral ischemia. We evaluated spatial memory using the Morris water maze and investigated the expression of α-amino-3-hydroxy-5-4-isoxazole propionic acid receptor subunits, the phosphorylation level of glutamate receptor A (GluA)1 at serine sites S831 and S845, and the Ca2+/calmodulin-dependent protein kinase II (CaMKII) in the hippocampus and prefrontal cortex of CI + Aß rats. In the CI + Aß rats, NYT treatment shortened the extended time to reach the platform. However, NYT did not restore the decrease in the hippocampal GluA1, GluA2, or CaMKII expression but increased prefrontal cortical phosphorylation levels of S845-GluA1 and CaMKII. Therefore, NYT may alleviate spatial memory impairment by promoting glutamatergic transmission involved in the phosphorylation of S845-GluA1 and CaMKII in the prefrontal cortex of CI + Aß rats. Our results suggest that NYT is a valuable treatment for AD patients.

Ninjinyoeito Prevents Onset of Depression-Like Behavior and Reduces Hippocampal iNOS Expression in Senescence-Accelerated Mouse Prone 8 Mice.

Late-life depression is a globally prevalent disorder. Ninjinyoeito (NYT), a traditional Japanese herbal medicine, attenuates depressive symptoms in older patients. However, the mechanisms underlying the antidepressive effect of NYT are unknown. In this study, we investigated the mechanism of the action of NYT using senescence-accelerated mouse prone 8 (SAMP8) mice, which exhibit accelerated aging. SAMP8 mice were treated with NYT starting at 12 weeks of age. Twelve-week-old SAMP8 mice did not show prolonged immobility time in the tail suspension test compared with age-matched SAMR1 mice (normal aging control). At 34 weeks of age, vehicle-treated SAMP8 mice displayed prolonged immobility time compared with SAMR1 mice. NYT-treated SAMP8 mice showed a shorter immobility time than that of vehicle-treated SAMP8 mice. Notably, NYT decreased hippocampal inducible nitric oxide synthase (iNOS) expression in SAMP8 mice. There was no difference in iNOS expression between SAMR1 and vehicle-treated SAMP8 mice. Subchronic (5 days) administration of an iNOS inhibitor, 1400 W, shortened the immobility time in SAMP8 mice. These results suggest that NYT prevents an increase in immobility time of SAMP8 mice by decreasing iNOS levels in the hippocampus. Therefore, the antidepressive effect of NYT in older patients might be mediated, at least in part, by the downregulation of iNOS in the brain. Our data suggest that NYT is useful to prevent the onset of depression with aging.

Astrocyte Ca2+ signaling is facilitated in Scn1a+/- mouse model of Dravet syndrome.

Dravet syndrome (DS) is an infantile-onset epileptic encephalopathy. More than 80% of DS patients have a heterozygous mutation in SCN1A, which encodes a subunit of the voltage-gated sodium channel, Nav1.1, in neurons. The roles played by astrocytes, the most abundant glial cell type in the brain, have been investigated in the pathogenesis of epilepsy; however, the specific involvement of astrocytes in DS has not been clarified. In this study, we evaluated Ca2+ signaling in astrocytes using genetically modified mice that have a loss-of-function mutation in Scn1a. We found that the slope of spontaneous Ca2+ spiking was increased without a change in amplitude in Scn1a+/- astrocytes. In addition, ATP-induced transient Ca2+ influx and the slope of Ca2+ spiking were also increased in Scn1a+/- astrocytes. These data indicate that perturbed Ca2+ dynamics in astrocytes may be involved in the pathogenesis of DS.

Delivery of the reduced form of vitamin K2(20) to NIH/3T3 cells partially protects against rotenone induced cell death.

Mitochondria generate energy through the action of the electron transport chain (ETC) and ATP synthase. Mitochondrial malfunction can lead to various disorders, including neurodegenerative diseases. Several reports have shown that menaquinone-4 (MK-4, vitamin K2(20)), a safe drug for osteoporosis, may improve mitochondrial function. Here, we hypothesized that the efficient delivery of menahydroquinone-4 (MKH), an active form of MK-4, could exert a supporting effect. We verified the effects of MKH delivery on mitochondrial dysfunction by using MK-4 and MKH ester derivatives in NIH/3T3 mouse fibroblast cells treated with mitochondrial inhibitors. MK-4 and MKH derivatives suppressed cell death, the decline in mitochondrial membrane potential (MMP), excessive reactive oxygen species (ROS) production, and a decrease in intrinsic coenzyme Q9 (CoQ9) induced by rotenone (ROT, complex I inhibitor). MK-4 and MKH derivatives delivered MKH to NIH/3T3 cells, acting as an effective MKH prodrug, proving that the delivered MKH may reflect the mitigation effects on ROT-induced mitochondrial dysfunction. MKH prodrugs are also effective against 3-nitropropionic acid (3-NP, complex II inhibitor) and carbonyl cyanide-m-chlorophenylhydrazone (CCCP, uncoupler)-induced cell death. In conclusion, MKH delivery may mitigate mitochondrial dysfunction by maintaining MMP, ROS, and CoQ9, indicating that MKH prodrugs may be good candidates for treating mitochondrial disorders.

Kamishoyosan Alleviates Anxiety-like Behavior in a Premenstrual Syndrome Rat Model.

Kamishoyosan (KSS) is a traditional Japanese Kampo medicine that is prescribed for hormonal change-induced mood disorders including premenstrual syndrome (PMS). In clinical studies, KSS exhibited ameliorative effects on mood symptoms of PMS, such as anxiety and irritability. However, the mechanism underlying the beneficial effects of KSS is unclear. In the present study, we investigated the involvement of serotonergic machinery in the anxiolytic effects of KSS on hormonally-induced anxiety-like behavior in progesterone withdrawal (PWD) rats, which were used as a model of PMS. Female rats were injected with progesterone daily for 21 days. At 48 h after the final progesterone injection, anxiety-like behavior was evaluated using the elevated plus maze. KSS was administered orally to PWD rats 1 h prior to the test and significantly attenuated PWD-induced anxiety-like behavior. This ameliorative effect of KSS was reversed by WAY-100635, a serotonin (5-HT)1A receptor antagonist. The effect of KSS on serotonergic transmission in the prefrontal cortex of PWD rats was also evaluated using an in vivo microdialysis procedure. KSS significantly increased the extracellular 5-HT level in the prefrontal cortex of PWD rats. In conclusion, our results suggest that KSS alleviates PWD-induced anxiety-like behavior at least partly by activating 5-HT1A receptors and enhancing serotonergic transmission.

Establishment of autaptic culture with human-induced pluripotent stem cell-derived astrocytes.

Although astrocytes are involved in the pathogenesis of CNS diseases, how they induce synaptic abnormalities is unclear. Currently, in vitro pathological astrocyte cultures or animal models do not reproduce human disease phenotypes accurately. Induced pluripotent stem cells (iPSCs) are replacing animal models in pathological studies. We developed an autaptic culture (AC) system containing single neuron cultures grown on microislands of astrocytes. AC with human iPSC-derived astrocytes (HiA) was established. We evaluated the effect of astrocytes on the synaptic functions of human-derived neurons. We found a significantly higher Na+ current amplitude, membrane capacitance, and number of synapses, as well as longer dendrites, in HiAACs compared with neuron monocultures. Furthermore, HiAs were involved in the formation and maturation of functional synapses that exhibited excitatory postsynaptic currents. This system can facilitate the study of CNS diseases and advance the development of drugs targeting glial cells.

Sansoninto attenuates aggressive behavior and increases levels of homovanillic acid, a dopamine metabolite, in social isolation-reared mice.

Background and aim: Early-life stress is thought to affect aggressive behavior in humans and rodents. Laboratory experiments have demonstrated that Sansoninto (SST; suan zǎo rén tang), a traditional herbal medicine, attenuates stress-induced abnormal behavior in rodents. However, it is unknown whether SST attenuates stress-induced aggressive behavior. The current study examined the effects of SST on aggressive behavior of mice who suffered from social isolation (SI) stress in adolescence. Experimental procedure: Five-week old mice were socially isolated for 6 weeks, and SST administration was started at 4 weeks after starting SI. Aggressive behavior and locomotor activity were examined in SST-treated mice. The content of dopamine and its metabolites in the hypothalamus were examined using high-performance liquid chromatography analysis. Gene expression analyses of monoamine oxidase-B (MAO-B), catechol-O-methyltransferase (COMT), and tyrosine hydroxylase in the hypothalamus were performed using quantitative reverse transcription polymerase chain reaction. Results and conclusion: SST attenuated SI-induced aggressive behavior and increased levels of homovanillic acid, a metabolite of dopamine. However, SST did not affect dopamine levels. SI enhanced locomotion in a novel environment and increased COMT mRNA levels. In contrast, SST-treated mice showed no significant enhancement of locomotion. SST attenuated the increase in COMT mRNA levels. Given that the dopaminergic system has been implicated in aggressive behavior, these findings suggest that SST toned down dopaminergic signaling, resulting in amelioration of aggression. SST may be useful for treatment of aggressive behavior in patients with neurotic symptoms.

The impact of fetal growth restriction in diagnosing preeclampsia on the severity of maternal features.

AIM: We aimed to assess the impact of fetal growth restriction (FGR) as a diagnostic criterion for preeclampsia (PE) on the severity of maternal preeclamptic features by comparing it with other diagnostic criteria for PE, maternal organ dysfunction. METHODS: We performed a retrospective cohort study of singleton pregnancies. Based on the status at diagnosis, PE cases preceded by FGR without maternal organ dysfunction (Group F; n = 28) and those preceded by maternal organ dysfunction without FGR (Group M; n = 87) were analyzed. RESULTS: Group F had an earlier PE diagnosis (32.5 ± 4.9 vs. 36.7 ± 3.5 weeks, p < 0.01) and delivery (33.7 ± 4.5 vs. 37.5 ± 3.1 weeks, p < 0.01) than Group M. No significant differences in maternal morbidities were observed between the groups, including severe hypertension (75.0 vs. 60.0%), need for intravenous antihypertensives (42.9 vs. 48.3%) or magnesium sulfate (60.7 vs. 54.5%), or a composite of major maternal complications (17.9 vs. 21.8%). When limited to early-onset PE diagnosed before 34 weeks of gestation (17 and 17 cases in Group F and M, respectively), the frequencies of maternal morbidities (severe hypertension: 70.6 vs. 52.9%, intravenous antihypertensives: 35.3 vs. 35.3%, magnesium sulfate: 58.8 vs. 47.1%, major complications: 29.4 vs. 23.5%) and the duration from diagnosis until delivery (11.2 ± 14.7 vs. 16.5 ± 21.7 days) were comparable between two groups. CONCLUSIONS: Our results suggest that the presence of FGR on PE diagnosis is associated with the development of severe maternal symptoms as much as that of maternal organ dysfunction at diagnosis, and it may be reasonable to include FGR in PE diagnostic criteria.

[Clinical Outcome of Heart Transplantation in Osaka University].

In this article, we analyzed 114 adult heart transplantation( HTx) cases from 1999 to 2021. Of these cases, 94% of patients underwent left ventricular assist device ( LVAD) implantation before HTx. The mean period of LVAD support was 3.0 ±1.2 years. Thirty-day mortality was 0.8% and the 10-year survival rate was 89% after HTx. Preoperative and postoperative renal function was the prognostic factors. Long LVAD support was not associated with the long-term survival after HTx.

Behavioral profile in a Dctn1G71A knock-in mouse model of Perry disease.

Perry disease (Perry syndrome) is a rare, rapidly progressive, autosomal dominant neurodegenerative disease characterized by parkinsonism, depression/apathy, weight loss, and respiratory symptoms including central hypoventilation. It is caused by missense mutations (e.g. p.G71A) in the DCTN1 gene. We previously generated transgenic mice that expressed human DCTN1G71A mutant protein under the control of Thy1 promoter. These mice exhibited apathy-like behavior and parkinsonism. However, it is possible that this phenotype was due to a gene-dosage imbalance or transgene insertion position. To circumvent these potential caveats, we have generated a knock-in mouse model carrying a p.G71A mutation in Dctn1. Heterozygous Dctn1G71A and wild-type littermates were subjected to a battery of behavioral analyses. Furthermore, immunohistochemistry for tyrosine hydroxylase (TH) was performed on brain sections of these mice, and TH signal intensity in substantia nigral neurons was quantified. Dctn1G71A mice were immobile for longer than wild-type mice of the same age and sex in the tail-suspension test, revealing depressive characteristics. In addition, the beam-walking test and pole test detected motor deficits in Dctn1G71A female mice. Finally, immunostaining revealed a decrease in TH immunoreactivity in neurons of the substantia nigra in the Dctn1G71A mice. Collectively, heterozygous Dctn1G71A mice showed depression-like behavior, motor deficits, and a functional reduction in substantia nigral neurons, as judged by TH immunostaining, thereby exhibiting multiple features of Perry disease. Hence, this mouse model will be useful in elucidating pathological mechanisms of Perry disease and for developing novel therapeutic strategies against it.

Kamishoyosan potentiates pentobarbital-induced sleep in socially isolated, ovariectomized mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Sleep disorders are among the most common symptoms in both peri- and post-menopausal women. Kamishoyosan (KSS) is a Kampo medicine prescribed for the treatment of sleep disorders in menopausal women in Japan. However, its precise mechanism of action remains unclear. AIM OF THE STUDY: In the present study, we developed a new animal model of menopausal sleep disorders by inducing social isolation stress in ovariectomized mice. Using pentobarbital-induced sleeping time as an index, we aimed to investigate the effects of KSS and involvement of the benzodiazepine receptors. MATERIALS AND METHODS: Eight-week-old, female ddY mice were ovariectomized or subjected to a sham operation (control) and housed in social isolation or groups for 9 weeks. The animals were divided into four groups, group-housed sham-operated, isolated sham-operated, group-housed ovariectomized, and socially isolated ovariectomized. Pentobarbital (50 mg/kg) was administered intraperitoneally (i.p.). Sleeping time was considered the period between the loss of righting reflex and its return (up to 180 min). KSS was administered orally (p.o.) 60 min before the test. Diazepam and flumazenil were administered i.p. 30 and 45 min before the test, respectively. On the day after administration, the mice were euthanized, and their uteri were weighed. RESULTS: Socially isolated, ovariectomized mice had shorter sleeping times than mice in all other groups. In mice with intact ovaries, diazepam (1 mg/kg, i.p.) considerably prolonged the pentobarbital-induced sleeping time, but KSS (30-1000 mg/kg, p.o.) did not. However, KSS (100 mg/kg, p.o.) significantly prolonged the pentobarbital-induced sleeping time in socially isolated ovariectomized mice. The prolongation of sleeping time mediated by KSS was reversed by flumazenil (3 mg/kg, i.p.). CONCLUSIONS: KSS potentiated pentobarbital-induced sleep in socially isolated, ovariectomized mice, and the benzodiazepine receptors are possibly involved in its pharmacological mechanism. These findings suggest that KSS is beneficial for the treatment of menopausal sleep disorders.

Ibudilast suppresses oxaliplatin-induced mechanical allodynia and neurodegeneration in rats.

Oxaliplatin is a key drug used in the management of solid tumors, such as colorectal cancer; however, it causes peripheral neuropathy. In this study, we investigated the effect of ibudilast, a phosphodiesterase inhibitor, on oxaliplatin-induced mechanical allodynia and histological changes in rats. Ibudilast (7.5 mg/kg, i.p., 5 times per week) reduced mechanical allodynia and histological changes induced by oxaliplatin (4 mg/kg, i.p., twice a week). In contrast, ibudilast (0.01-10 µM) had no effect on oxaliplatin-induced tumor cytotoxicity in murine colon adenocarcinoma 26 cells. These findings suggest that ibudilast could be useful for preventing oxaliplatin-induced peripheral neuropathy in clinical settings.

The novel mitochondria activator, 10-ethyl-3-methylpyrimido[4,5-b]quinoline-2,4(3H,10H)-dione (TND1128), promotes the development of hippocampal neuronal morphology.

Adenosine triphosphate (ATP) is the most vital energy source produced mainly in the mitochondria. Age-related mitochondrial dysfunction is associated with brain diseases. Nicotinamide adenine dinucleotide (NAD+) is an essential cofactor for energy production in mitochondria. Here, we examined how the novel NAD+-assisting substance, 10-ethyl-3-methylpyrimido[4,5-b]quinoline-2,4(3H,10H)-dione (TND1128), modulates the morphological growth of cultured mouse hippocampal neurons. The morphological growth effect of TND1128 was also compared with that of ß-nicotinamide mononucleotide (ß-NMN). TND1128 induced the branching of axons and dendrites, and increased the number of excitatory synapses. This study provides new insight into TND1128 as a mitochondria-stimulating drug for improving brain function.

Inhibitory synaptic transmission is impaired at higher extracellular Ca2+ concentrations in Scn1a+/- mouse model of Dravet syndrome.

Dravet syndrome (DS) is an intractable form of childhood epilepsy that occurs in infancy. More than 80% of all patients have a heterozygous abnormality in the SCN1A gene, which encodes a subunit of Na+ channels in the brain. However, the detailed pathogenesis of DS remains unclear. This study investigated the synaptic pathogenesis of this disease in terms of excitatory/inhibitory balance using a mouse model of DS. We show that excitatory postsynaptic currents were similar between Scn1a knock-in neurons (Scn1a+/- neurons) and wild-type neurons, but inhibitory postsynaptic currents were significantly lower in Scn1a+/- neurons. Moreover, both the vesicular release probability and the number of inhibitory synapses were significantly lower in Scn1a+/- neurons compared with wild-type neurons. There was no proportional increase in inhibitory postsynaptic current amplitude in response to increased extracellular Ca2+ concentrations. Our study revealed that the number of inhibitory synapses is significantly reduced in Scn1a+/- neurons, while the sensitivity of inhibitory synapses to extracellular Ca2+ concentrations is markedly increased. These data suggest that Ca2+ tethering in inhibitory nerve terminals may be disturbed following the synaptic burst, likely leading to epileptic symptoms.

DCTN1 Binds to TDP-43 and Regulates TDP-43 Aggregation.

A common pathological hallmark of several neurodegenerative diseases, including amyotrophic lateral sclerosis, is cytoplasmic mislocalization and aggregation of nuclear RNA-binding protein TDP-43. Perry disease, which displays inherited atypical parkinsonism, is a type of TDP-43 proteinopathy. The causative gene DCTN1 encodes the largest subunit of the dynactin complex. Dynactin associates with the microtubule-based motor cytoplasmic dynein and is required for dynein-mediated long-distance retrograde transport. Perry disease-linked missense mutations (e.g., p.G71A) reside within the CAP-Gly domain and impair the microtubule-binding abilities of DCTN1. However, molecular mechanisms by which such DCTN1 mutations cause TDP-43 proteinopathy remain unclear. We found that DCTN1 bound to TDP-43. Biochemical analysis using a panel of truncated mutants revealed that the DCTN1 CAP-Gly-basic supradomain, dynactin domain, and C-terminal region interacted with TDP-43, preferentially through its C-terminal region. Remarkably, the p.G71A mutation affected the TDP-43-interacting ability of DCTN1. Overexpression of DCTN1G71A, the dynactin-domain fragment, or C-terminal fragment, but not the CAP-Gly-basic fragment, induced cytoplasmic mislocalization and aggregation of TDP-43, suggesting functional modularity among TDP-43-interacting domains of DCTN1. We thus identified DCTN1 as a new player in TDP-43 cytoplasmic-nuclear transport, and showed that dysregulation of DCTN1-TDP-43 interactions triggers mislocalization and aggregation of TDP-43, thus providing insights into the pathological mechanisms of Perry disease and other TDP-43 proteinopathies.

Valproic acid-exposed astrocytes impair inhibitory synapse formation and function.

Valproic acid (VPA) is widely prescribed to treat epilepsy. Maternal VPA use is, however, clinically restricted because of the severe risk that VPA may cause neurodevelopmental disorders in offspring, such as autism spectrum disorder. Understanding the negative action of VPA may help to prevent VPA-induced neurodevelopmental disorders. Astrocytes play a vital role in neurodevelopment and synapse function; however, the impact of VPA on astrocyte involvement in neurodevelopment and synapse function has not been examined. In this study, we examined whether exposure of cultured astrocytes to VPA alters neuronal morphology and synapse function of co-cultured neurons. We show that synaptic transmission by inhibitory neurons was small because VPA-exposed astrocytes reduced the number of inhibitory synapses. However, synaptic transmission by excitatory neurons and the number of excitatory synapses were normal with VPA-exposed astrocytes. VPA-exposed astrocytes did not affect the morphology of inhibitory neurons. These data indicate that VPA-exposed astrocytes impair synaptogenesis specifically of inhibitory neurons. Our results indicate that maternal use of VPA would affect not only neurons but also astrocytes and would result in perturbed astrocyte-mediated neurodevelopment.