1
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Honan LE, Fraser-Spears R, Daws LC. Organic cation transporters in psychiatric and substance use disorders. Pharmacol Ther 2024; 253:108574. [PMID: 38072333 PMCID: PMC11052553 DOI: 10.1016/j.pharmthera.2023.108574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 11/01/2023] [Accepted: 11/30/2023] [Indexed: 12/23/2023]
Abstract
Psychiatric and substance use disorders inflict major public health burdens worldwide. Their widespread burden is compounded by a dearth of effective treatments, underscoring a dire need to uncover novel therapeutic targets. In this review, we summarize the literature implicating organic cation transporters (OCTs), including three subtypes of OCTs (OCT1, OCT2, and OCT3) and the plasma membrane monoamine transporter (PMAT), in the neurobiology of psychiatric and substance use disorders with an emphasis on mood and anxiety disorders, alcohol use disorder, and psychostimulant use disorder. OCTs transport monoamines with a low affinity but high capacity, situating them to play a central role in regulating monoamine homeostasis. Preclinical evidence discussed here suggests that OCTs may serve as promising targets for treatment of psychiatric and substance use disorders and encourage future research into their therapeutic potential.
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Affiliation(s)
- Lauren E Honan
- The University of Texas Health Science Center at San Antonio, Department of Cellular & Integrative Physiology, USA
| | - Rheaclare Fraser-Spears
- University of the Incarnate Word, Feik School of Pharmacy, Department of Pharmaceutical Sciences, USA
| | - Lynette C Daws
- The University of Texas Health Science Center at San Antonio, Department of Cellular & Integrative Physiology, USA; The University of Texas Health Science Center at San Antonio, Department of Pharmacology, USA.
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2
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Weber BL, Nicodemus MM, Hite AK, Spalding IR, Beaver JN, Scrimshaw LR, Kassis SK, Reichert JM, Ford MT, Russell CN, Hallal EM, Gilman TL. Heterotypic Stressors Unmask Behavioral Influences of PMAT Deficiency in Mice. Int J Mol Sci 2023; 24:16494. [PMID: 38003684 PMCID: PMC10671398 DOI: 10.3390/ijms242216494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 11/16/2023] [Accepted: 11/16/2023] [Indexed: 11/26/2023] Open
Abstract
Certain life stressors having enduring physiological and behavioral consequences, in part by eliciting dramatic signaling shifts in monoamine neurotransmitters. High monoamine levels can overwhelm selective transporters like the serotonin transporter. This is when polyspecific transporters like plasma membrane monoamine transporter (PMAT, Slc29a4) are hypothesized to contribute most to monoaminergic signaling regulation. Here, we employed two distinct counterbalanced stressors-fear conditioning and swim stress-in mice to systematically determine how reductions in PMAT function affect heterotypic stressor responsivity. We hypothesized that male heterozygotes would exhibit augmented stressor responses relative to female heterozygotes. Decreased PMAT function enhanced context fear expression, an effect unexpectedly obscured by a sham stress condition. Impaired cued fear extinction retention and enhanced context fear expression in males were conversely unmasked by a sham swim condition. Abrogated corticosterone levels in male heterozygotes that underwent swim stress after context fear conditioning did not map onto any measured behaviors. In sum, male heterozygous mouse fear behaviors proved malleable in response to preceding stressor or sham stress exposure. Combined, these data indicate that reduced male PMAT function elicits a form of stress-responsive plasticity. Future studies should assess how PMAT is differentially affected across sexes and identify downstream consequences of the stress-shifted corticosterone dynamics.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - T. Lee Gilman
- Department of Psychological Sciences, Brain Health Research Institute, Healthy Communities Research Institute, Kent State University, Kent, OH 44240, USA
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3
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Weber BL, Nicodemus MM, Hite AK, Spalding IR, Beaver JN, Scrimshaw LR, Kassis SK, Reichert JM, Ford MT, Russell CN, Hallal EM, Gilman TL. Heterotypic stressors unmask behavioral influences of PMAT deficiency in mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.30.555632. [PMID: 37693400 PMCID: PMC10491137 DOI: 10.1101/2023.08.30.555632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Certain life stressors having enduring physiological and behavioral consequences, in part by eliciting dramatic signaling shifts in monoamine neurotransmitters. High monoamine levels can overwhelm selective transporters like the serotonin transporter. This is when polyspecific transporters like plasma membrane monoamine transporter (PMAT, Slc29a4) are hypothesized to contribute most to monoaminergic signaling regulation. Here, we employed two distinct counterbalanced stressors - fear conditioning, and swim stress - in mice to systematically determine how reductions in PMAT function affect heterotypic stressor responsivity. We hypothesized male heterozygotes would exhibit augmented stressor responses relative to female heterozygotes. Decreased PMAT function enhanced context fear expression, an effect unexpectedly obscured by a sham stress condition. Impaired cued fear extinction retention and enhanced context fear expression in males were conversely unmasked by a sham swim condition. Abrogated corticosterone levels in male heterozygotes that underwent swim stress after context fear conditioning did not map on to any measured behaviors. In sum, male heterozygous mouse fear behaviors proved malleable in response to preceding stressor or sham stress exposure. Combined, these data indicate reduced male PMAT function elicits a form of stress-responsive plasticity. Future studies should assess how PMAT is differentially affected across sexes and identify downstream consequences of the stress-shifted corticosterone dynamics.
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Affiliation(s)
- Brady L Weber
- Department of Psychological Sciences, Brain Health Research Institute, Healthy Communities Research Institute, Kent State University, Kent, OH, USA
| | - Marissa M Nicodemus
- Department of Psychological Sciences, Brain Health Research Institute, Healthy Communities Research Institute, Kent State University, Kent, OH, USA
| | - Allianna K Hite
- Department of Psychological Sciences, Brain Health Research Institute, Healthy Communities Research Institute, Kent State University, Kent, OH, USA
| | - Isabella R Spalding
- Department of Psychological Sciences, Brain Health Research Institute, Healthy Communities Research Institute, Kent State University, Kent, OH, USA
| | - Jasmin N Beaver
- Department of Psychological Sciences, Brain Health Research Institute, Healthy Communities Research Institute, Kent State University, Kent, OH, USA
| | - Lauren R Scrimshaw
- Department of Psychological Sciences, Brain Health Research Institute, Healthy Communities Research Institute, Kent State University, Kent, OH, USA
| | - Sarah K Kassis
- Department of Psychological Sciences, Brain Health Research Institute, Healthy Communities Research Institute, Kent State University, Kent, OH, USA
| | - Julie M Reichert
- Department of Psychological Sciences, Brain Health Research Institute, Healthy Communities Research Institute, Kent State University, Kent, OH, USA
| | - Matthew T Ford
- Department of Psychological Sciences, Brain Health Research Institute, Healthy Communities Research Institute, Kent State University, Kent, OH, USA
| | - Cameron N Russell
- Department of Psychological Sciences, Brain Health Research Institute, Healthy Communities Research Institute, Kent State University, Kent, OH, USA
| | - Elayna M Hallal
- Department of Psychological Sciences, Brain Health Research Institute, Healthy Communities Research Institute, Kent State University, Kent, OH, USA
| | - T Lee Gilman
- Department of Psychological Sciences, Brain Health Research Institute, Healthy Communities Research Institute, Kent State University, Kent, OH, USA
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4
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Weber BL, Beaver JN, Gilman TL. Summarizing studies using constitutive genetic deficiency to investigate behavioural influences of uptake 2 monoamine transporters. Basic Clin Pharmacol Toxicol 2023; 133:439-458. [PMID: 36316031 PMCID: PMC10657738 DOI: 10.1111/bcpt.13810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 10/14/2022] [Accepted: 10/24/2022] [Indexed: 11/27/2022]
Abstract
Burgeoning literature demonstrates that monoamine transporters with high transport capacity but lower substrate affinity (i.e., uptake 2) contribute meaningfully to regulation of monoamine neurotransmitter signalling. However, studying behavioural influences of uptake 2 is hindered by an absence of selective inhibitors largely free of off-target, confounding effects. This contrasts with study of monoamine transporters with low transport capacity but high substrate affinity (i.e., uptake 1), for which there are many reasonably selective inhibitors. To circumvent this dearth of pharmacological tools for studying uptake 2, researchers have instead employed mice with constitutive genetic deficiency in three separate transporters. By studying baseline behavioural shifts, plus behavioural responses to environmental and pharmacological manipulations-the latter primarily targeting uptake 1-investigators have been creatively characterizing the behavioural, and often sex-specific, influences of uptake 2. This non-systematic mini review summarizes current uptake 2 behaviour literature, highlighting emphases on stress responsivity in organic cation transporter 2 (OCT2) work, psychostimulant responsivity in OCT3 and plasma membrane monoamine transporter (PMAT) investigations, and antidepressant responsivity in all three. Collectively, this small but growing body of work reiterates the necessity for development of selective uptake 2-inhibiting drugs, with reviewed studies suggesting that these might advance personalized treatment approaches.
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Affiliation(s)
- Brady L Weber
- Department of Psychological Sciences & Brain Health Research Institute, Kent State University, Kent, Ohio, USA
| | - Jasmin N Beaver
- Department of Psychological Sciences & Brain Health Research Institute, Kent State University, Kent, Ohio, USA
| | - T Lee Gilman
- Department of Psychological Sciences & Brain Health Research Institute, Kent State University, Kent, Ohio, USA
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5
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Contribution of ENT4 to adenosine uptake in AC16 human cardiomyocytes under simulated ischemic conditions and its potential role in cardioprotection. Mol Biol Rep 2022; 49:11201-11208. [DOI: 10.1007/s11033-022-07902-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 08/19/2022] [Accepted: 08/24/2022] [Indexed: 10/14/2022]
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Beaver JN, Weber BL, Ford MT, Anello AE, Kassis SK, Gilman TL. Uncovering Functional Contributions of PMAT ( Slc29a4) to Monoamine Clearance Using Pharmacobehavioral Tools. Cells 2022; 11:cells11121874. [PMID: 35741002 PMCID: PMC9220966 DOI: 10.3390/cells11121874] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/01/2022] [Accepted: 06/07/2022] [Indexed: 11/16/2022] Open
Abstract
Plasma membrane monoamine transporter (PMAT, Slc29a4) transports monoamine neurotransmitters, including dopamine and serotonin, faster than more studied monoamine transporters, e.g., dopamine transporter (DAT), or serotonin transporter (SERT), but with ~400–600-fold less affinity. A considerable challenge in understanding PMAT’s monoamine clearance contributions is that no current drugs selectively inhibit PMAT. To advance knowledge about PMAT’s monoamine uptake role, and to circumvent this present challenge, we investigated how drugs that selectively block DAT/SERT influence behavioral readouts in PMAT wildtype, heterozygote, and knockout mice of both sexes. Drugs typically used as antidepressants (escitalopram, bupropion) were administered acutely for readouts in tail suspension and locomotor tests. Drugs with psychostimulant properties (cocaine, D-amphetamine) were administered repeatedly to assess initial locomotor responses plus psychostimulant-induced locomotor sensitization. Though we hypothesized that PMAT-deficient mice would exhibit augmented responses to antidepressant and psychostimulant drugs due to constitutively attenuated monoamine uptake, we instead observed sex-selective responses to antidepressant drugs in opposing directions, and subtle sex-specific reductions in psychostimulant-induced locomotor sensitization. These results suggest that PMAT functions differently across sexes, and support hypotheses that PMAT’s monoamine clearance contribution emerges when frontline transporters (e.g., DAT, SERT) are absent, saturated, and/or blocked. Thus, known human polymorphisms that reduce PMAT function could be worth investigating as contributors to varied antidepressant and psychostimulant responses.
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7
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Dalla C, Pavlidi P, Sakelliadou DG, Grammatikopoulou T, Kokras N. Sex Differences in Blood–Brain Barrier Transport of Psychotropic Drugs. Front Behav Neurosci 2022; 16:844916. [PMID: 35677576 PMCID: PMC9169874 DOI: 10.3389/fnbeh.2022.844916] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 04/27/2022] [Indexed: 11/13/2022] Open
Abstract
Treatment of neuropsychiatric disorders relies on the effective delivery of therapeutic molecules to the target organ, the brain. The blood–brain barrier (BBB) hinders such delivery and proteins acting as transporters actively regulate the influx and importantly the efflux of both endo- and xeno-biotics (including medicines). Neuropsychiatric disorders are also characterized by important sex differences, and accumulating evidence supports sex differences in the pharmacokinetics and pharmacodynamics of many drugs that act on the brain. In this minireview we gather preclinical and clinical findings on how sex and sex hormones can influence the activity of those BBB transporter systems and affect the brain pharmacokinetics of psychotropic medicines. It emerges that it is not well understood which psychotropics are substrates for each of the many and not well-studied brain transporters. Indeed, most evidence originates from studies performed in peripheral tissues, such as the liver and the kidneys. None withstanding, accumulated evidence supports the existence of several sex differences in expression and activity of transport proteins, and a further modulating role of gonadal hormones. It is proposed that a closer study of sex differences in the active influx and efflux of psychotropics from the brain may provide a better understanding of sex-dependent brain pharmacokinetics and pharmacodynamics of psychotropic medicines.
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Affiliation(s)
- Christina Dalla
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Pavlina Pavlidi
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Danai-Georgia Sakelliadou
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Tatiana Grammatikopoulou
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Nikolaos Kokras
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
- First Department of Psychiatry, Eginition Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
- *Correspondence: Nikolaos Kokras,
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8
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Gu Y, Zhang N, Zhu S, Lu S, Jiang H, Zhou H. Estradiol reduced 5-HT reuptake by Downregulating the Gene Expression of Plasma Membrane Monoamine Transporter (PMAT, Slc29a4) through estrogen receptor β and the MAPK/ERK signaling pathway. Eur J Pharmacol 2022; 924:174939. [PMID: 35398393 DOI: 10.1016/j.ejphar.2022.174939] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/30/2022] [Accepted: 03/31/2022] [Indexed: 12/22/2022]
Abstract
Estrogen deficiency-induced female depression is closely related to 5-hydroxytriptamine (5-HT) deficiency. Estradiol (17β-estradiol, E2) regulates the monoamine transporters and acts as an antidepressant by affecting 5-HT clearance through estrogen receptors and related signaling pathways at the genome level, although the specific mechanisms require further exploration. The brain expresses higher levels of plasma membrane monoamine transporter (PMAT, involved in 5-HT reuptake of the uptake 2 system) than other uptake transporters. In this study, we found that estrogen-deficient ovariectomized (OVX) rats had high PMAT mRNA and protein expression levels in the hippocampus and estradiol significantly reduced these levels. Furthermore, estradiol inhibits PMAT expression and reduced 5-HT reuptake in neurons and astrocytes and estradiol regulated the PMAT expression mainly by affecting estrogen receptor β (ERβ) at the genomic level in astrocytes. Further cell and animal experiments showed that estradiol also regulated PMAT expression through the MAPK/ERK signaling pathway and not through the PI3K/AKT signaling pathway. In conclusion, estradiol inhibits 5-HT reuptake by regulating PMAT expression at the genomic level through ERβ and the MAPK/ERK signaling pathway, highlighting the importance of PMAT in the antidepressant effects of estradiol through 5-HT clearance reduction.
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Affiliation(s)
- Yong Gu
- Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, PR China
| | - Nanxin Zhang
- Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, PR China
| | - Shujie Zhu
- Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, PR China
| | - Shuanghui Lu
- Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, PR China
| | - Huidi Jiang
- Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, PR China; Jinhua Institute of Zhejiang University, Jinhua, Zhejiang, PR China
| | - Hui Zhou
- Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, PR China; Jinhua Institute of Zhejiang University, Jinhua, Zhejiang, PR China.
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9
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Clauss NJ, Koek W, Daws LC. Role of Organic Cation Transporter 3 and Plasma Membrane Monoamine Transporter in the Rewarding Properties and Locomotor Sensitizing Effects of Amphetamine in Male andFemale Mice. Int J Mol Sci 2021; 22:ijms222413420. [PMID: 34948221 PMCID: PMC8708598 DOI: 10.3390/ijms222413420] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 12/03/2021] [Accepted: 12/03/2021] [Indexed: 01/03/2023] Open
Abstract
A lack of effective treatment and sex-based disparities in psychostimulant addiction and overdose warrant further investigation into mechanisms underlying the abuse-related effects of amphetamine-like stimulants. Uptake-2 transporters such as organic cation transporter 3 (OCT3) and plasma membrane monoamine transporter (PMAT), lesser studied potential targets for the actions of stimulant drugs, are known to play a role in monoaminergic neurotransmission. Our goal was to examine the roles of OCT3 and PMAT in mediating amphetamine (1 mg/kg)-induced conditioned place preference (CPP) and sensitization to its locomotor stimulant effects, in males and females, using pharmacological, decynium-22 (D22; 0.1 mg/kg, a blocker of OCT3 and PMAT) and genetic (constitutive OCT3 and PMAT knockout (−/−) mice) approaches. Our results show that OCT3 is necessary for the development of CPP to amphetamine in males, whereas in females, PMAT is necessary for the ability of D22 to prevent the development of CPP to amphetamine. Both OCT3 and PMAT appear to be important for development of sensitization to the locomotor stimulant effect of amphetamine in females, and PMAT in males. Taken together, these findings support an important, sex-dependent role of OCT3 and PMAT in the rewarding and locomotor stimulant effects of amphetamine.
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Affiliation(s)
- Nikki J. Clauss
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
- Correspondence: (N.J.C.); (L.C.D.)
| | - Wouter Koek
- Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA;
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Lynette C. Daws
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
- Correspondence: (N.J.C.); (L.C.D.)
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Abstract
Selective serotonin reuptake inhibitors (SSRIs) are the most commonly prescribed medications for psychiatric disorders, yet they leave the majority of patients without full symptom relief. Therefore, a major research challenge is to identify novel targets for the improved treatment of these disorders. SSRIs act by blocking the serotonin transporter (SERT), the high-affinity, low-capacity, uptake-1 transporter for serotonin. Other classes of antidepressant work by blocking the norepinephrine or dopamine transporters (NET and DAT), the high-affinity, low-capacity uptake-1 transporters for norepinephrine and dopamine, or by blocking combinations of SERT, NET, and DAT. It has been proposed that uptake-2 transporters, which include organic cation transporters (OCTs) and the plasma membrane monoamine transporter (PMAT), undermine the therapeutic utility of uptake-1 acting antidepressants. Uptake-2 transporters for monoamines have low affinity for these neurotransmitters, but a high capacity to transport them. Thus, activity of these transporters may limit the increase of extracellular monoamines thought to be essential for ultimate therapeutic benefit. Here preclinical evidence supporting a role for OCT2, OCT3, and PMAT in behaviors relevant to psychiatric disorders is presented. Importantly, preclinical evidence revealing these transporters as targets for the development of novel therapeutics for psychiatric disorders is discussed.
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11
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Sweet DH. Organic Cation Transporter Expression and Function in the CNS. Handb Exp Pharmacol 2021; 266:41-80. [PMID: 33963461 DOI: 10.1007/164_2021_463] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCSFB) represent major control checkpoints protecting the CNS, by exerting selective control over the movement of organic cations and anions into and out of the CNS compartment. In addition, multiple CNS cell types, e.g., astrocytes, ependymal cells, microglia, contribute to processes that maintain the status quo of the CNS milieu. To fulfill their roles, these barriers and cell types express a multitude of transporter proteins from dozens of different transporter families. Fundamental advances over the past few decades in our knowledge of transporter substrates, expression profiles, and consequences of loss of function are beginning to change basic theories regarding the contribution of various cell types and clearance networks to coordinated neuronal signaling, complex organismal behaviors, and overall CNS homeostasis. In particular, transporters belonging to the Solute Carrier (SLC) superfamily are emerging as major contributors, including the SLC22 organic cation/anion/zwitterion family of transporters (includes OCT1-3 and OCTN1-3), the SLC29 facilitative nucleoside family of transporters (includes PMAT), and the SLC47 multidrug and toxin extrusion family of transporters (includes MATE1-2). These transporters are known to interact with neurotransmitters, antidepressant and anxiolytic agents, and drugs of abuse. Clarifying their contributions to the underlying mechanisms regulating CNS permeation and clearance, as well as the health status of astrocyte, microglial and neuronal cell populations, will drive new levels of understanding as to maintenance of the CNS milieu and approaches to new therapeutics and therapeutic strategies in the treatment of CNS disorders. This chapter highlights organic cation transporters belonging to the SLC superfamily known to be expressed in the CNS, providing an overview of their identification, mechanism of action, CNS expression profile, interaction with neurotransmitters and antidepressant/antipsychotic drugs, and results from behavioral studies conducted in loss of function models (knockout/knockdown).
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Affiliation(s)
- Douglas H Sweet
- Department of Pharmaceutics, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, USA.
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12
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Long-term antibiotic use during early life and risks to mental traits: an observational study and gene-environment-wide interaction study in UK Biobank cohort. Neuropsychopharmacology 2021; 46:1086-1092. [PMID: 32801349 PMCID: PMC8115166 DOI: 10.1038/s41386-020-00798-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 07/26/2020] [Accepted: 08/04/2020] [Indexed: 02/08/2023]
Abstract
The relationships between long-term antibiotic use during early life and mental traits remain elusive now. A total of 158,444 subjects from UK Biobank were used in this study. Linear regression analyses were first conducted to assess the correlations between long-term antibiotic use during early life and mental traits. Gene-environment-wide interaction study (GEWIS) was then performed by PLINK2.0 to detect the interaction effects between long-term antibiotic use during early life and genes on the risks of mental traits. Finally, DAVID tool was used to conduct gene ontology (GO) analysis of the identified genes interacting with long-term antibiotic use during early life. We found negative associations of long-term antibiotic use during early life with remembrance (p value=1.74 × 10-6, b = -0.10) and intelligence (p value=2.64 × 10-26, b = -0.13), and positive associations of long-term antibiotic use during early life with anxiety (p value = 2.75 × 10-47, b = 0.12) and depression (p value=2.01 × 10-195, b = 0.25). GEWIS identified multiple significant genes-long-term antibiotic use during early life interaction effects, such as ANK3 (rs773585997, p value = 1.78 × 10-8) for anxiety and STRN (rs140049205, p value = 1.88 × 10-8) for depression. GO enrichment analysis detected six GO terms enriched in the identified genes interacting with long-term antibiotic use during early life for anxiety, such as GO:0030425~dendrite (p value = 3.41 × 10-2) and GO:0005886~plasma membrane (p value = 3.64 × 10-3). Our study results suggest the impact of long-term antibiotic use during early life on the development of mental traits.
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13
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Abstract
Inhibitors of Na+/Cl- dependent high affinity transporters for norepinephrine (NE), serotonin (5-HT), and/or dopamine (DA) represent frequently used drugs for treatment of psychological disorders such as depression, anxiety, obsessive-compulsive disorder, attention deficit hyperactivity disorder, and addiction. These transporters remove NE, 5-HT, and/or DA after neuronal excitation from the interstitial space close to the synapses. Thereby they terminate transmission and modulate neuronal behavioral circuits. Therapeutic failure and undesired central nervous system side effects of these drugs have been partially assigned to neurotransmitter removal by low affinity transport. Cloning and functional characterization of the polyspecific organic cation transporters OCT1 (SLC22A1), OCT2 (SLC22A2), OCT3 (SLC22A3) and the plasma membrane monoamine transporter PMAT (SLC29A4) revealed that every single transporter mediates low affinity uptake of NE, 5-HT, and DA. Whereas the organic transporters are all located in the blood brain barrier, OCT2, OCT3, and PMAT are expressed in neurons or in neurons and astrocytes within brain areas that are involved in behavioral regulation. Areas of expression include the dorsal raphe, medullary motoric nuclei, hypothalamic nuclei, and/or the nucleus accumbens. Current knowledge of the transport of monoamine neurotransmitters by the organic cation transporters, their interactions with psychotropic drugs, and their locations in the brain is reported in detail. In addition, animal experiments including behavior tests in wildtype and knockout animals are reported in which the impact of OCT2, OCT3, and/or PMAT on regulation of salt intake, depression, mood control, locomotion, and/or stress effect on addiction is suggested.
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Affiliation(s)
- Hermann Koepsell
- Institute of Anatomy and Cell Biology, University Würzburg, Würzburg, Germany.
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14
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Abstract
Precise control of monoamine neurotransmitter levels in the central nervous system (CNS) is crucial for proper brain function. Dysfunctional monoamine signaling is associated with several neuropsychiatric and neurodegenerative disorders. The plasma membrane monoamine transporter (PMAT) is a new polyspecific organic cation transporter encoded by the SLC29A4 gene. Capable of transporting monoamine neurotransmitters with low affinity and high capacity, PMAT represents a major uptake2 transporter in the brain. Broadly expressed in multiple brain regions, PMAT can complement the high-affinity, low-capacity monoamine uptake mediated by uptake1 transporters, the serotonin, dopamine, and norepinephrine transporters (SERT, DAT, and NET, respectively). This chapter provides an overview of the molecular and functional characteristics of PMAT together with its regional and cell-type specific expression in the mammalian brain. The physiological functions of PMAT in brain monoamine homeostasis are evaluated in light of its unique transport kinetics and brain location, and in comparison with uptake1 and other uptake2 transporters (e.g., OCT3) along with corroborating experimental evidences. Lastly, the possibility of PMAT's involvement in brain pathophysiological processes, such as autism, depression, and Parkinson's disease, is discussed in the context of disease pathology and potential link to aberrant monoamine pathways.
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15
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Naganuma F, Yoshikawa T. Organic Cation Transporters in Brain Histamine Clearance: Physiological and Psychiatric Implications. Handb Exp Pharmacol 2021; 266:169-185. [PMID: 33641029 DOI: 10.1007/164_2021_447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Histamine acts as a neurotransmitter in the central nervous system and is involved in numerous physiological functions. Recent studies have identified the causative role of decreased histaminergic systems in various neurological disorders. Thus, the brain histamine system has attracted attention as a therapeutic target to improve brain function. Neurotransmitter clearance is one of the most important processes for the regulation of neuronal activity and is an essential target for diverse drugs. Our previous study has shown the importance of histamine N-methyltransferase for the inactivation of brain histamine and the intracellular localization of this enzyme; the study indicated that the transport system for the movement of positively charged histamine from the extracellular to intracellular space is a prerequisite for histamine inactivation. Several studies on in vitro astrocytic histamine transport have indicated the contribution of organic cation transporter 3 (OCT3) and plasma membrane monoamine transporter (PMAT) in histamine uptake, although the importance of these transporters in in vivo histamine clearance remains unknown. Immunohistochemical analyses have revealed the expression of OCT3 and PMAT on neurons, emphasizing the importance of investigating neuronal histamine uptake. Further studies using knockout mice or fast-scan cyclic voltammetry will accelerate the research on histamine transporters. In this review article, we summarize histamine transport assays and describe the candidate transporters responsible for histamine transport in the brain.
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Affiliation(s)
- Fumito Naganuma
- Department of Pharmacology, Tohoku University Graduate School of Medicine, Sendai, Japan.,Division of Pharmacology, Faculty of Medicine, Tohoku Medical and Pharmaceutical University, Sendai, Japan
| | - Takeo Yoshikawa
- Department of Pharmacology, Tohoku University Graduate School of Medicine, Sendai, Japan.
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Bhat S, El-Kasaby A, Freissmuth M, Sucic S. Functional and Biochemical Consequences of Disease Variants in Neurotransmitter Transporters: A Special Emphasis on Folding and Trafficking Deficits. Pharmacol Ther 2020; 222:107785. [PMID: 33310157 PMCID: PMC7612411 DOI: 10.1016/j.pharmthera.2020.107785] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 12/02/2020] [Indexed: 01/30/2023]
Abstract
Neurotransmitters, such as γ-aminobutyric acid, glutamate, acetyl choline, glycine and the monoamines, facilitate the crosstalk within the central nervous system. The designated neurotransmitter transporters (NTTs) both release and take up neurotransmitters to and from the synaptic cleft. NTT dysfunction can lead to severe pathophysiological consequences, e.g. epilepsy, intellectual disability, or Parkinson’s disease. Genetic point mutations in NTTs have recently been associated with the onset of various neurological disorders. Some of these mutations trigger folding defects in the NTT proteins. Correct folding is a prerequisite for the export of NTTs from the endoplasmic reticulum (ER) and the subsequent trafficking to their pertinent site of action, typically at the plasma membrane. Recent studies have uncovered some of the key features in the molecular machinery responsible for transporter protein folding, e.g., the role of heat shock proteins in fine-tuning the ER quality control mechanisms in cells. The therapeutic significance of understanding these events is apparent from the rising number of reports, which directly link different pathological conditions to NTT misfolding. For instance, folding-deficient variants of the human transporters for dopamine or GABA lead to infantile parkinsonism/dystonia and epilepsy, respectively. From a therapeutic point of view, some folding-deficient NTTs are amenable to functional rescue by small molecules, known as chemical and pharmacological chaperones.
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Affiliation(s)
- Shreyas Bhat
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria
| | - Ali El-Kasaby
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria
| | - Michael Freissmuth
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria
| | - Sonja Sucic
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria.
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Bowman MA, Vitela M, Clarke KM, Koek W, Daws LC. Serotonin Transporter and Plasma Membrane Monoamine Transporter Are Necessary for the Antidepressant-Like Effects of Ketamine in Mice. Int J Mol Sci 2020; 21:ijms21207581. [PMID: 33066466 PMCID: PMC7589995 DOI: 10.3390/ijms21207581] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/09/2020] [Accepted: 10/12/2020] [Indexed: 01/17/2023] Open
Abstract
Major depressive disorder is typically treated with selective serotonin reuptake inhibitors (SSRIs), however, SSRIs take approximately six weeks to produce therapeutic effects, if any. Not surprisingly, there has been great interest in findings that low doses of ketamine, a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist, produce rapid and long-lasting antidepressant effects. Preclinical studies show that the antidepressant-like effects of ketamine are dependent upon availability of serotonin, and that ketamine increases extracellular serotonin, yet the mechanism by which this occurs is unknown. Here we examined the role of the high-affinity, low-capacity serotonin transporter (SERT), and the plasma membrane monoamine transporter (PMAT), a low-affinity, high-capacity transporter for serotonin, as mechanisms contributing to ketamine’s ability to increase extracellular serotonin and produce antidepressant-like effects. Using high-speed chronoamperometry to measure real-time clearance of serotonin from CA3 region of hippocampus in vivo, we found ketamine robustly inhibited serotonin clearance in wild-type mice, an effect that was lost in mice constitutively lacking SERT or PMAT. As expected, in wild-type mice, ketamine produced antidepressant-like effects in the forced swim test. Mapping onto our neurochemical findings, the antidepressant-like effects of ketamine were lost in mice lacking SERT or PMAT. Future research is needed to understand how constitutive loss of either SERT or PMAT, and compensation that occurs in other systems, is sufficient to void ketamine of its ability to inhibit serotonin clearance and produce antidepressant-like effects. Taken together with existing literature, a critical role for serotonin, and its inhibition of uptake via SERT and PMAT, cannot be ruled out as important contributing factors to ketamine’s antidepressant mechanism of action. Combined with what is already known about ketamine’s action at NMDA receptors, these studies help lead the way to the development of drugs that lack ketamine’s abuse potential but have superior efficacy in treating depression.
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Affiliation(s)
- Melodi A. Bowman
- Department of Cellular and Integrative Physiology at University of Texas Health, San Antonio, TX 78229, USA; (M.A.B.); (M.V.); (K.M.C.)
| | - Melissa Vitela
- Department of Cellular and Integrative Physiology at University of Texas Health, San Antonio, TX 78229, USA; (M.A.B.); (M.V.); (K.M.C.)
| | - Kyra M. Clarke
- Department of Cellular and Integrative Physiology at University of Texas Health, San Antonio, TX 78229, USA; (M.A.B.); (M.V.); (K.M.C.)
- Department of Pharmacology at University of Texas Health, San Antonio, TX 78229, USA;
| | - Wouter Koek
- Department of Pharmacology at University of Texas Health, San Antonio, TX 78229, USA;
- Department of Psychiatry at University of Texas Health, San Antonio, TX 78229, USA
| | - Lynette C. Daws
- Department of Cellular and Integrative Physiology at University of Texas Health, San Antonio, TX 78229, USA; (M.A.B.); (M.V.); (K.M.C.)
- Department of Pharmacology at University of Texas Health, San Antonio, TX 78229, USA;
- Correspondence:
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Zhu S, Lei S, Zhou S, Jin L, Zeng S, Jiang H, Zhou H. Luteolin shows antidepressant-like effect by inhibiting and downregulating plasma membrane monoamine transporter (PMAT, Slc29a4). J Funct Foods 2019. [DOI: 10.1016/j.jff.2019.01.048] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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Sun S, Zhou S, Lei S, Zhu S, Wang K, Jiang H, Zhou H. Jatrorrhizine reduces 5-HT and NE uptake via inhibition of uptake-2 transporters and produces antidepressant-like action in mice. Xenobiotica 2019; 49:1237-1243. [DOI: 10.1080/00498254.2018.1542188] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Siyuan Sun
- Department of Pharmaceutical Analysis and Drug Metabolism, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, PR China
- Department of Dermatology and Venereology, School of Medicine, Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, PR China
| | - Sisi Zhou
- Department of Pharmaceutical Analysis and Drug Metabolism, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, PR China
| | - Shaowei Lei
- Department of Pharmaceutical Analysis and Drug Metabolism, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, PR China
| | - Shujie Zhu
- Department of Pharmaceutical Analysis and Drug Metabolism, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, PR China
| | - Kai Wang
- Department of Pharmaceutical Analysis and Drug Metabolism, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, PR China
| | - Huidi Jiang
- Department of Pharmaceutical Analysis and Drug Metabolism, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, PR China
| | - Hui Zhou
- Department of Pharmaceutical Analysis and Drug Metabolism, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, PR China
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