Search

The coronavirus disease 2019 (COVID-19) pandemic affected people at all ages. Whereas pregnant women seemed to have a worse course of disease than age-matched non-pregnant women, the risk of feto-placental infection is low. Using a cohort of 66 COVID-19-positive women in late pregnancy, we correlated clinical parameters with disease severity, placental histopathology, and the expression of viral entry and Interferon-induced transmembrane (IFITM) antiviral transcripts. All newborns were negative for SARS-CoV-2. None of the demographic parameters or placental histopathological characteristics were associated with disease severity. The fetal-maternal transfer ratio for IgG against the N or S viral proteins was commonly less than one, as recently reported. We found that the expression level of placental ACE2, but not TMPRSS2 or Furin, was higher in women with severe COVID-19. Placental expression of IFITM1 and IFITM3, which have been implicated in antiviral response, was higher in participants with severe disease. We also showed that IFITM3 protein expression, which localized to early and late endosomes, was enhanced in severe COVID-19. Our data suggest an association between disease severity and placental SARS-CoV-2 processing and antiviral pathways, implying a role for these proteins in placental response to SARS-CoV-2., (© 2021. The Author(s).)

Dopamine transporter (DAT) controls dopamine neurotransmission by clearing synaptically released dopamine. However, trafficking itineraries of DAT, which determine its cell-surface concentration near synapses, are poorly characterized. It is especially unknown how DAT is transported between spatially distant midbrain somatodendritic and striatal axonal compartments. To examine this "long-range" trafficking, the localization and membrane diffusion of HA-epitope tagged DAT in the medial forebrain bundle (MFB) of a knock-in mouse (both sexes) were analyzed using confocal, super-resolution and EM in intact brain and acute brain slices. HA-DAT was abundant in the plasma membrane of MFB axons, similar to the striatum, although the intracellular fraction of HA-DAT in MFB was more substantial. Intracellular HA-DAT colocalized with VPS35, a subunit of the retromer complex mediating recycling from endosomes, in a subset of axons. Late endosomes, lysosomes, and endoplasmic reticulum were abundant in the soma but minimally present in MFB axons, suggesting that biosynthesis and lysosomal degradation of DAT are confined to soma. Together, the data suggest that membrane diffusion is the main mode of long-range DAT transport through MFB, although the contribution of vesicular traffic can be significant in a population of MFB axons. Based on HA-DAT diffusion rates, plasma membrane DAT in MFB axons turns over with a halftime of ∼20 d, which explains the extremely slow turnover of DAT protein in the brain. Unexpectedly, the mean diameter of DAT-labeled MFB axons was observed to be twice larger than reported for striatum. The implications of this finding for dopamine neuron physiology are discussed. SIGNIFICANCE STATEMENT The dopamine transporter (DAT) is a key regulator of dopamine neurotransmission and a target of abused psychostimulants. In the present study, we examined, for the first time, mechanisms of the long-range traffic of DAT in intact brain and acute brain slices from the knock-in mouse expressing epitope-tagged DAT. Using a combination of confocal, super-resolution and EM, we defined DAT localization and its membrane diffusion parameters in medial forebrain bundle axonal tracts connecting midbrain somatodendritic and striatal axonal compartments of dopaminergic neurons. In contrast to the widely accepted model of long-range axonal transport, our studies suggest that DAT traffics between midbrain and striatum, mainly by lateral diffusion in the plasma membrane with only a limited contribution of vesicular transport in recycling endosomes., (Copyright © 2021 the authors.)

Dopamine transporter (DAT) mediates the reuptake of synaptically released dopamine, and thus controls the duration and intensity of dopamine neurotransmission. Mammalian DAT has been observed to form oligomers, although the mechanisms of oligomerization and its role in DAT activity and trafficking remain largely unknown. We discovered a series of small molecule compounds that stabilize trimers and induce high-order oligomers of DAT and concomitantly promote its clathrin-independent endocytosis. Using a combination of chemical cross-linking, fluorescence resonance energy transfer microscopy, antibody-uptake endocytosis assay, live-cell lattice light sheet microscopy, ligand binding and substrate transport kinetics analyses, and molecular modeling and simulations, we investigated molecular basis of DAT oligomerization and endocytosis induced by these compounds. Our study showed that small molecule-induced DAT oligomerization and endocytosis are favored by the inward-facing DAT conformation and involve interactions of four hydrophobic residues at the interface between transmembrane (TM) helices TM4 and TM9. Surprisingly, a corresponding quadruple DAT mutant displays altered dopamine transport kinetics and increased cocaine-analog binding. The latter is shown to originate from an increased preference for outward-facing conformation and inward-to-outward transition. Taken together, our results demonstrate a direct coupling between conformational dynamics of DAT, functional activity of the transporter, and its oligomerization leading to endocytosis. The high specificity of such coupling for DAT makes the TM4-9 hub a new target for pharmacological modulation of DAT activity and subcellular localization., Competing Interests: Conflict of interest The authors declare no conflicts of interest in regards to this manuscript., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: 2-Deoxy-2-[ 18 F] fluoro-d-glucose positron emission tomography ( 18 F-FDG-PET) is a less-invasive and widely used diagnostic tool for detection of malignant tumors. However, prolonged retention of 18 F-FDG in the body increases radiation exposure. This study evaluated the effect of oral administration of milk and ursodeoxycholic acid (UDCA) in terms of reducing radiation exposure by 18 F-FDG., Methods: 18 F-FDG radioactivity was measured using a digital γ counter in the whole body and in various organs of rats after oral administration of milk and milk plus UDCA (milk + UDCA). Western blotting was performed to measure the expression levels of G6Pase, HK 2, CREB, FoxO1, and PGC-1α in the brain, liver, small intestine, and large intestine to assess the mechanism underlying the reduction in radiation exposure from 18 F-FDG by oral administration of milk and UDCA., Results: We found a significant reduction in 18 F-FDG radioactivity in the whole body and in the brain, liver, and small and large intestines. Expression of G6Pase was significantly increased in the above-mentioned organs in the milk and milk + UDCA groups. Expression of HK 2 was significantly decreased in the brain and small intestine in the milk and milk + UDCA groups. CREB, FoxO1, and PGC-1α expression levels in the brain, liver, and small intestine were increased in the milk and milk + UDCA groups. However, expression of PGC-1α in the large intestine in the milk and milk + UDCA groups was significantly decreased compared with that in the control group., Conclusion: The present study demonstrated that administration of milk and UDCA increased G6Pase expression levels and 18 F-FDG release from the tissue. These results suggest milk and UDCA could be used to reduce radiation exposure from 18 F-FDG after image acquisition. The mechanisms underpinning this phenomenon should be explored in a human study., Competing Interests: Conflict of InterestHwan-Jeong Jeong, Tarique Rajasaheb Bagalkot, Hyeon Soo Kim, Yeon-Hee Han, Minjoo Kim, Seok Tae Lim, and Myung-Hee Sohn declare that they have no conflict of interest., (© Korean Society of Nuclear Medicine 2020.)

Exposing adrenal chromaffin cells to single 150 to 400 ns electric pulses triggers a rise in intracellular Ca 2+ ([Ca 2+ ] i ) that is due to Ca 2+ influx through voltage-gated Ca 2+ channels (VGCC) and plasma membrane electropores. Immediate delivery of a second pulse of the opposite polarity in which the duration and amplitude were the same as the first pulse (a symmetrical bipolar pulse) or greater than the first pulse (an asymmetrical bipolar pulse) had a stimulatory effect, evoking larger Ca 2+ responses than the corresponding unipolar pulse. Progressively decreasing the amplitude of the opposite polarity pulse while also increasing its duration converted stimulation to attenuation, which reached a maximum of 43% when the positive phase was 150 ns at 3.1 kV/cm, and the negative phase was 800 ns at 0.2 kV/cm. When VGCCs were blocked, Ca 2+ responses evoked by asymmetrical and even symmetrical bipolar pulses were significantly reduced relative to those evoked by the corresponding unipolar pulse under the same conditions, indicating that attenuation involved mainly the portion of Ca 2+ influx attributable to membrane electropermeabilization. Thus, by tuning the shape of the bipolar pulse, Ca 2+ entry into chromaffin cells through electropores could be attenuated while preserving Ca 2+ influx through VGCCs.

Background: Chronic social defeat stress induces depression and anxiety-like behaviors in rodents and also responsible for differentiating defeated animals into stress susceptible and resilient groups. The present study investigated the effects of social defeat stress on a variety of behavioral parameters like social behavior, spatial learning and memory and anxiety like behaviors. Additionally, the levels of various dopaminergic markers, including the long and short form of the D2 receptor, and total and phosphorylated dopamine and cyclic adenosine 3',5'-monophosphate regulated phosphoprotein-32, and proteins involved in intracellular trafficking were assessed in several key brain regions in young adult mice., Methods: Mouse model of chronic social defeat was established by resident-intruder paradigm, and to evaluate the effect of chronic social defeat, mice were subjected to behavioral tests like spontaneous locomotor activity, elevated plus maze (EPM), social interaction and Morris water maze tests., Results: Mice were divided into susceptible and unsusceptible groups after 10 days of social defeat stress. The susceptible group exhibited greater decreases in time spent in the open and closed arms compared to the control group on the EPM. In the social interaction test, the susceptible group showed greater increases in submissive and neutral behaviors and greater decreases in social behaviors relative to baseline compared to the control group. Furthermore, increased expression of D2L, D2S, Rab4, and G protein-coupled receptor associated sorting protein-1 was observed in the amygdala of the susceptible group compared to the control group., Conclusion: These findings suggest that social defeat stress induce anxiety-like and altered social interacting behaviors, and changes in dopaminergic markers and intracellular trafficking-related proteins.

Exposing adrenal chromaffin cells to 5 ns electric pulses (nsPEF) causes a rapid rise in intracellular Ca 2+ ([Ca 2+ ] i ) that is solely the result of Ca 2+ influx through voltage-gated Ca 2+ channels (VGCCs). This study explored the effect of longer duration nsPEF on [Ca 2+ ] i . Single 150, 200, or 400 ns pulses at 3.1 kV/cm evoked rapid increases in [Ca 2+ ] i , the magnitude of which increased linearly with pulse width and electric field amplitude. Recovery of [Ca 2+ ] i to prestimulus levels was faster for 150 ns exposures. Regardless of pulse width, no rise in [Ca 2+ ] i occurred in the absence of extracellular Ca 2+ , indicating that the source of Ca 2+ was from outside the cell. Ca 2+ responses evoked by a 150 ns pulse were inhibited to varying degrees by ω -agatoxin IVA, ω -conotoxin GVIA, nitrendipine or nimodipine, antagonists of P/Q-, N-, and L-type VGCCs, respectively, and by 67% when all four types of VGCCs were blocked simultaneously. The remaining Ca 2+ influx insensitive to VGCC inhibitors was attributed to plasma membrane nanoporation, which comprised the E -field sensitive component of the response. Both pathways of Ca 2+ entry were inhibited by 200  μ M Cd 2+ . These results demonstrate that, in excitable chromaffin cells, single 150-400 ns pulses increased the permeability of the plasma membrane to Ca 2+ in addition to causing Ca 2+ influx via VGCCs.

The present study aimed to examine the effects of chronic social defeat stress on the dopamine receptors and proteins involved in post-endocytic trafficking pathways. Adult mice were divided into susceptible and unsusceptible groups after 10 days of social defeat stress. Western blot analysis was used to measure the protein expression levels of dopamine D2 receptors (D2Rs), a short (D2S) and a long form (D2L) and, D2R monomers and dimers, dopamine D1 receptors (D1Rs), neuronal calcium sensor-1 (NCS-1) and G protein-coupled receptor-associated sorting protein-1 (GASP-1), and reverse transcription-polymerase chain reaction (RT-PCR) was used to measure the mRNA expression levels of D2S, D2L, D2R monomers and dimers, and D1Rs in different brain areas. We observed increased expression of D2S, D2L and D2Rs dimers in the prefrontal cortex (PFC) of susceptible and/or unsusceptible mice compared with controls. The only significant findings with regard to mRNA expression levels were lower expression of D2S mRNA in the amygdala (AMYG) of susceptible and unsusceptible mice compared with controls. The present study demonstrated that chronic social defeat stress induced increased expression of D2S, D2L, and D2R dimers in the PFC of susceptible and/or unsusceptible mice., (Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.)

The present study investigated the effects of chronic social defeat stress on several behavioral parameters, and the expression of dopaminergic markers, i.e., dopamine D1 receptors (D1Rs), dopamine D2 receptors (D2Rs), and dopamine and cyclic adenosine 3',5'-monophosphate-regulated phosphoprotein-32 (DARPP-32), in the prefrontal cortex (PFC), amygdala (AMY), and hippocampus (HIP) of mouse brains. After 10days of social defeat stress, the defeated mice were divided into two groups: one group underwent a series of behavioral tests. The other group was sacrificed on the 11th day and tissue samples were collected for Western blotting. The behavioral tests comprised tests of locomotion, light/dark preference, social interaction, as well as the novel object recognition test (NORT), Morris water maze, and forced swimming test (FST). We measured the expression of D1Rs, D2Rs, total DARPP-32, phospho-Thr34 or Thr75-DARPP-32 using Western blotting. The defeated mice showed increased anxiety- and depression-like behaviors, and impaired cognition. No significant differences in D1Rs and D2Rs expression were shown between defeated and control mice in any area studied. A significantly increased expression in total DARPP-32, and phospho-DARPP-32 was observed in the PFC or AMY of defeated mice. These data suggest that alterations in dopaminergic markers may be involved in anxiety- and depression-like behaviors, and cognitive impairment induced by social defeat stress., (Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.)

Objectives: Our study evaluated the lifetime prevalence of and risk factors for suicidal ideation and suicide attempts in Jeollabuk-do Province, Korea., Method: Participants were selected from the population of individuals aged 13-100 years living Jeollabuk-do Province, Korea. A total of 2,964 subjects provided information about lifetime suicidal behavior and sociodemographic and psychological characteristics, completing the Zung Depression Scale, the Scale for Suicidal Ideation, the Multidimensional Anger Inventory, and the Rosenberg Self-Esteem Scale., Results: The lifetime prevalence of suicidal ideation and suicide attempts, 24.8% and 6.2%, respectively, were higher than in previous studies. Multivariate regression revealed that family harmony had the highest odds ratio of all variables, including psychological factors. Along with depression and self-esteem, anger--which is the basic symptom of the Korean culture-related anger syndrome, Hwa-byung--was significantly associated with lifetime suicidal behavior., Conclusions: Lifetime suicidal behavior was highly prevalent in Jeollabuk-do Province. The most significant risk factors were found to be social support, family disharmony, anger, depression, and low self-esteem in Koreans.

The anti-apoptotic protein Bax inhibitor-1 (BI-1) is a regulator of apoptosis linked to endoplasmic reticulum (ER) stress. It has been hypothesized that BI-1 protects against neuron degenerative diseases. In this study, BI-1⁻/⁻ mice showed increased vulnerability to chronic mild stress accompanied by alterations in the size and morphology of the hippocampi, enhanced ROS accumulation and an ER stress response compared with BI-1⁺/⁺ mice. BI-1⁻/⁻ mice exposed to chronic mild stress showed significant activation of monoamine oxidase A (MAO-A), but not MAO-B, compared with BI-1⁺/⁺ mice. To examine the involvement of BI-1 in the Ca²⁺-sensitive MAO activity, thapsigargin-induced Ca²⁺ release and MAO activity were analyzed in neuronal cells overexpressing BI-1. The in vitro study showed that BI-1 regulates Ca²⁺ release and related MAO-A activity. This study indicates an endogenous protective role of BI-1 under conditions of chronic mild stress that is primarily mediated through Ca²⁺-associated MAO-A regulation.

The present study investigated the effects of social defeat stress on the behaviours and expressions of 78-kDa glucose-regulated protein (Grp78), CCAAT/enhancer-binding protein (C/EBP) homologous protein (CHOP) and choline acetyltransferase (Chat) in the brains of adolescent mice. Adolescent male C57BL/6J mice were divided into two groups (susceptible and unsusceptible) after 10 d social defeat stress. In expt 1, behavioural tests were conducted and brains were processed for Western blotting on day 21 after stress. In expt 2, social avoidance tests were conducted and brains were subsequently processed for Western blotting on day 12 after stress. Chronic social defeat stress produced more pronounced depression-like behaviours such as decreased locomotion and social interaction, increased anxiety-like behaviours and immobility, and impaired memory performance in susceptible mice. Moreover, susceptible mice showed greater expression of Grp78 and CHOP in the amygdala (Amyg) on days 12 and 21 compared with the other groups. Susceptible and unsusceptible groups showed significant increases in Grp78 and CHOP expression in the prefrontal cortex (PFC) and hippocampus (Hipp) on day 12 compared with the control group; this persisted until day 21. The levels of Chat measured on days 12 and 21 were significantly lower in the PFC, Amyg and Hipp of all defeated mice compared with controls. The findings of the behavioural tests indicate that chronic social defeat in adolescents produces anxiety-like behaviours, social withdrawal, despair-like behaviours and cognitive impairment. The Grp78, CHOP and Chat results suggest that the selective response of endoplasmic reticulum stress proteins in the Amyg plays an important role in the vulnerability-stress model of depression.

Rationale: Social defeat stress induces physiological and behavioral symptoms, including anxiety, anhedonia, immune deficits, and altered expression of key brain genes., Objectives: The present study investigated the effects of social defeat stress on the behaviors and expressions of Chat, Grp78, and chop in the brains of adult mice., Methods: Adult mice were divided into susceptible and unsusceptible groups after 10 days of social defeat stress. In experiment 1, behavioral tests were conducted, and brains were processed for Western blotting at day 27 after stress. In experiment 2, social avoidance tests were conducted, and brains were processed for Western blotting at day 12 after stress., Results: The results indicate decreased and increased locomotion and anxiety behavior in all defeated mice. Decrease in social interaction, increased immobility, and impaired memory performance were only observed in susceptible mice. A decrease in the Chat level at days 12 and 27 was noted in the prefrontal cortex (PFC), amygdala (Amyg), and dorsal hippocampus (HIP) in defeated mice. The expression levels of Grp78 and chop measured on days 12 and 27 were significantly greater in the Amyg of susceptible mice. In the PFC and HIP, defeated mice displayed different patterns in the levels of Grp78 and chop expressions measured on days 12 and 27., Conclusions: The present study demonstrated that chronic social defeat stress in mice produces stress-related behaviors. Different response patterns were noted for Grp78 and chop expression among the groups in terms of brain regions and time-course effects.