Presynaptic Gq-coupled receptors drive biphasic dopamine transporter trafficking that modulates dopamine clearance and motor function

Extracellular dopamine (DA) levels are tightly constrained by presynaptic reuptake mediated by the DA transporter (DAT). Despite its necessity for DA neurotransmission, DAT regulation in situ is poorly understood, and it is unknown whether DAT regulation impacts dopaminergic signaling and/or behaviors. Here, we leveraged chemogenetics and conditional gene silencing and found that presynaptic Gq-coupled receptor activation, induced by either hM3Dq or mGluR5 activation, drives biphasic DAT trafficking in striatum. Two PD risk alleles, Vps35 and Rit2, were required for mGluR5-stimulated DAT insertion and retrieval, respectively. Conditional dopaminergic mGluR5 silencing abolished DAT trafficking and resulted in motor dysfunction. Moreover, ex vivo voltammetric studies demonstrate that DAT trafficking significantly impacts DA clearance. These studies reveal that presynaptic DAT trafficking is complex, multimodal, and region-specific, and identify cell autonomous mechanisms required for DAT trafficking. Importantly, the findings suggest that regulated DAT trafficking likely impacts both DA clearance and motor function.

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NTPDase1 Modulates Smooth Muscle Contraction in Mice Bladder by Regulating Nucleotide Receptor Activation Distinctly in Male and Female

Biomolecules ◽

10.3390/biom11020147 ◽

2021 ◽

Vol 11 (2) ◽

pp. 147

Author(s):

Romuald Brice Babou Kammoe ◽

Gilles Kauffenstein ◽

Julie Pelletier ◽

Bernard Robaye ◽

Jean Sévigny

Keyword(s):

Smooth Muscle ◽

Ex Vivo ◽

Smooth Muscle Contraction ◽

Receptor Activation ◽

Nucleoside Triphosphate ◽

Nucleotide Receptors ◽

Nerve Terminals ◽

Wild Type ◽

Nucleoside Triphosphate Diphosphohydrolase ◽

Bladder Contraction

Nucleotides released by smooth muscle cells (SMCs) and by innervating nerve terminals activate specific P2 receptors and modulate bladder contraction. We hypothesized that cell surface enzymes regulate SMC contraction in mice bladder by controlling the concentration of nucleotides. We showed by immunohistochemistry, enzymatic histochemistry, and biochemical activities that nucleoside triphosphate diphosphohydrolase-1 (NTPDase1) and ecto-5′-nucleotidase were the major ectonucleotidases expressed by SMCs in the bladder. RT-qPCR revealed that, among the nucleotide receptors, there was higher expression of P2X1, P2Y1, and P2Y6 receptors. Ex vivo, nucleotides induced a more potent contraction of bladder strips isolated from NTPDase1 deficient (Entpd1−/−) mice compared to wild type controls. The strongest responses were obtained with uridine 5′-triphosphate (UTP) and uridine 5′-diphosphate (UDP), suggesting the involvement of P2Y6 receptors, which was confirmed with P2ry6−/− bladder strips. Interestingly, this response was reduced in female bladders. Our results also suggest the participation of P2X1, P2Y2 and/or P2Y4, and P2Y12 in these contractions. A reduced response to the thromboxane analogue U46619 was also observed in wild type, Entpd1−/−, and P2ry6−/− female bladders showing another difference due to sex. In summary, NTPDase1 modulates the activation of nucleotide receptors in mouse bladder SMCs, and contractions induced by P2Y6 receptor activation were weaker in female bladders.

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Engineered Phage Endolysin Eliminates Gardnerella Biofilm without Damaging Beneficial Bacteria in Bacterial Vaginosis Ex Vivo

Pathogens ◽

10.3390/pathogens10010054 ◽

2021 ◽

Vol 10 (1) ◽

pp. 54

Author(s):

Christine Landlinger ◽

Lenka Tisakova ◽

Vera Oberbauer ◽

Timo Schwebs ◽

Abbas Muhammad ◽

...

Keyword(s):

Bacterial Vaginosis ◽

Bactericidal Activity ◽

High Selectivity ◽

Ex Vivo ◽

Vaginal Microbiome ◽

Wild Type ◽

Wild Type Enzyme ◽

Promising Alternative ◽

First Time

Bacterial vaginosis is characterized by an imbalance of the vaginal microbiome and a characteristic biofilm formed on the vaginal epithelium, which is initiated and dominated by Gardnerella bacteria, and is frequently refractory to antibiotic treatment. We investigated endolysins of the type 1,4-beta-N-acetylmuramidase encoded on Gardnerella prophages as an alternative treatment. When recombinantly expressed, these proteins demonstrated strong bactericidal activity against four different Gardnerella species. By domain shuffling, we generated several engineered endolysins with 10-fold higher bactericidal activity than any wild-type enzyme. When tested against a panel of 20 Gardnerella strains, the most active endolysin, called PM-477, showed minimum inhibitory concentrations of 0.13–8 µg/mL. PM-477 had no effect on beneficial lactobacilli or other species of vaginal bacteria. Furthermore, the efficacy of PM-477 was tested by fluorescence in situ hybridization on vaginal samples of fifteen patients with either first time or recurring bacterial vaginosis. In thirteen cases, PM-477 killed the Gardnerella bacteria and physically dissolved the biofilms without affecting the remaining vaginal microbiome. The high selectivity and effectiveness in eliminating Gardnerella, both in cultures of isolated strains as well as in clinically derived samples of natural polymicrobial biofilms, makes PM-477 a promising alternative to antibiotics for the treatment of bacterial vaginosis, especially in patients with frequent recurrence.

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Kisspeptin-8 Induces Anxiety-Like Behavior and Hypolocomotion by Activating the HPA Axis and Increasing GABA Release in the Nucleus Accumbens in Rats

Biomedicines ◽

10.3390/biomedicines9020112 ◽

2021 ◽

Vol 9 (2) ◽

pp. 112

Author(s):

Katalin Eszter Ibos ◽

Éva Bodnár ◽

Zsolt Bagosi ◽

Zsolt Bozsó ◽

Gábor Tóth ◽

...

Keyword(s):

Nucleus Accumbens ◽

Ex Vivo ◽

Gaba Release ◽

Receptor Activation ◽

Ambulatory Activity ◽

Corticosterone Concentration ◽

Reproductive Axis ◽

Neuropeptide Ff ◽

Serum Lh ◽

Anxiogenic Effect

Kisspeptins (Kp) are RF-amide neuropeptide regulators of the reproductive axis that also influence anxiety, locomotion, and metabolism. We aimed to investigate the effects of intracerebroventricular Kp-8 (an N-terminally truncated octapeptide) treatment in Wistar rats. Elevated plus maze (EPM), computerized open field (OF), and marble burying (MB) tests were performed for the assessment of behavior. Serum LH and corticosterone levels were determined to assess kisspeptin1 receptor (Kiss1r) activation and hypothalamic-pituitary-adrenal axis (HPA) stimulation, respectively. GABA release from the nucleus accumbens (NAc) and dopamine release from the ventral tegmental area (VTA) and NAc were measured via ex vivo superfusion. Kp-8 decreased open arm time and entries in EPM, and also raised corticosterone concentration, pointing to an anxiogenic effect. Moreover, the decrease in arm entries in EPM, the delayed increase in immobility accompanied by reduced ambulatory activity in OF, and the reduction in interactions with marbles show that Kp-8 suppressed exploratory and spontaneous locomotion. The increase in GABA release from the NAc might be in the background of hypolocomotion by inhibiting the VTA-NAc dopaminergic circuitry. As Kp-8 raised LH concentration, it could activate Kiss1r and stimulate the reproductive axis. As Kiss1r is associated with hyperlocomotion, it is more likely that neuropeptide FF receptor activation is involved in the suppression of locomotor activity.

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Capsazepine decreases corneal pain syndrome in severe dry eye disease

Journal of Neuroinflammation ◽

10.1186/s12974-021-02162-7 ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Darine Fakih ◽

Adrian Guerrero-Moreno ◽

Christophe Baudouin ◽

Annabelle Réaux-Le Goazigo ◽

Stéphane Mélik Parsadaniantz

Keyword(s):

In Situ Hybridization ◽

Inflammatory Pain ◽

Transient Receptor Potential ◽

Ex Vivo ◽

Receptor Potential ◽

Eye Disease ◽

Ocular Pain ◽

Trpv1 Antagonist ◽

Transient Receptor

Abstract Background Dry eye disease (DED) is a multifactorial disease of the ocular surface accompanied by neurosensory abnormalities. Here, we evaluated the effectiveness of transient receptor potential vanilloid-1 (TRPV1) blockade to alleviate ocular pain, neuroinflammation, and anxiety-like behavior associated with severe DED. Methods Chronic DED was induced by unilateral excision of the Harderian and extraorbital lacrimal glands of adult male mice. Investigations were conducted at 21 days after surgery. The mRNA levels of TRPV1, transient receptor potential ankyrin-1 (TRPA1), and acid-sensing ion channels 1 and 3 (ASIC1 and ASIC3) in the trigeminal ganglion (TG) were evaluated by RNAscope in situ hybridization. Multi-unit extracellular recording of ciliary nerve fiber activity was used to monitor spontaneous and stimulated (cold, heat, and acid) corneal nerve responsiveness in ex vivo eye preparations. DED mice received topical instillations of the TRPV1 antagonist (capsazepine) twice a day for 2 weeks from d7 to d21 after surgery. The expression of genes involved in neuropathic and inflammatory pain was evaluated in the TG using a global genomic approach. Chemical and mechanical corneal nociception and spontaneous ocular pain were monitored. Finally, anxiety-like behaviors were assessed by elevated plus maze and black and white box tests. Results First, in situ hybridization showed DED to trigger upregulation of TRPV1, TRPA1, ASIC1, and ASIC3 mRNA in the ophthalmic branch of the TG. DED also induced overexpression of genes involved in neuropathic and inflammatory pain in the TG. Repeated instillations of capsazepine reduced corneal polymodal responsiveness to heat, cold, and acidic stimulation in ex vivo eye preparations. Consistent with these findings, chronic capsazepine instillation inhibited the upregulation of genes involved in neuropathic and inflammatory pain in the TG of DED animals and reduced the sensation of ocular pain, as well as anxiety-like behaviors associated with severe DED. Conclusion These data provide novel insights on the effectiveness of TRPV1 antagonist instillation in alleviating abnormal corneal neurosensory symptoms induced by severe DED, opening an avenue for the repositioning of this molecule as a potential analgesic treatment for patients suffering from chronic DED.

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Dopamine Transporter Genetic Reduction Induces Morpho-Functional Changes in the Enteric Nervous System

Biomedicines ◽

10.3390/biomedicines9050465 ◽

2021 ◽

Vol 9 (5) ◽

pp. 465

Author(s):

Silvia Cerantola ◽

Valentina Caputi ◽

Gabriella Contarini ◽

Maddalena Mereu ◽

Antonella Bertazzo ◽

...

Keyword(s):

Nervous System ◽

Small Intestine ◽

Enteric Nervous System ◽

Dopamine Transporter ◽

Myenteric Plexus ◽

Receptor Activation ◽

D1 Receptor ◽

Functional Changes ◽

Neurochemical Coding ◽

The Impact

Antidopaminergic gastrointestinal prokinetics are indeed commonly used to treat gastrointestinal motility disorders, although the precise role of dopaminergic transmission in the gut is still unclear. Since dopamine transporter (DAT) is involved in several brain disorders by modulating extracellular dopamine in the central nervous system, this study evaluated the impact of DAT genetic reduction on the morpho-functional integrity of mouse small intestine enteric nervous system (ENS). In DAT heterozygous (DAT+/−) and wild-type (DAT+/+) mice (14 ± 2 weeks) alterations in small intestinal contractility were evaluated by isometrical assessment of neuromuscular responses to receptor and non-receptor-mediated stimuli. Changes in ENS integrity were studied by real-time PCR and confocal immunofluorescence microscopy in longitudinal muscle-myenteric plexus whole-mount preparations (). DAT genetic reduction resulted in a significant increase in dopamine-mediated effects, primarily via D1 receptor activation, as well as in reduced cholinergic response, sustained by tachykininergic and glutamatergic neurotransmission via NMDA receptors. These functional anomalies were associated to architectural changes in the neurochemical coding and S100β immunoreactivity in small intestine myenteric plexus. Our study provides evidence that genetic-driven DAT defective activity determines anomalies in ENS architecture and neurochemical coding together with ileal dysmotility, highlighting the involvement of dopaminergic system in gut disorders, often associated to neurological conditions.

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Generation of vascular chimerism within donor organs

Scientific Reports ◽

10.1038/s41598-021-92823-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Shahar Cohen ◽

Shirly Partouche ◽

Michael Gurevich ◽

Vladimir Tennak ◽

Vadym Mezhybovsky ◽

...

Keyword(s):

Ex Vivo ◽

Patient Specific ◽

Machine Perfusion ◽

Organ Perfusion ◽

Perfusion Process ◽

Hind Limbs ◽

Porcine Organs ◽

Immunological Barrier

AbstractWhole organ perfusion decellularization has been proposed as a promising method to generate non-immunogenic organs from allogeneic and xenogeneic donors. However, the ability to recellularize organ scaffolds with multiple patient-specific cells in a spatially controlled manner remains challenging. Here, we propose that replacing donor endothelial cells alone, while keeping the rest of the organ viable and functional, is more technically feasible, and may offer a significant shortcut in the efforts to engineer transplantable organs. Vascular decellularization was achieved ex vivo, under controlled machine perfusion conditions, in various rat and porcine organs, including the kidneys, liver, lungs, heart, aorta, hind limbs, and pancreas. In addition, vascular decellularization of selected organs was performed in situ, within the donor body, achieving better control over the perfusion process. Human placenta-derived endothelial progenitor cells (EPCs) were used as immunologically-acceptable human cells to repopulate the luminal surface of de-endothelialized aorta (in vitro), kidneys, lungs and hind limbs (ex vivo). This study provides evidence that artificially generating vascular chimerism is feasible and could potentially pave the way for crossing the immunological barrier to xenotransplantation, as well as reducing the immunological burden of allogeneic grafts.

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