Serotonin Transporter Research Articles

Colitis-Induced Small Intestinal Hypomotility Is Dependent on Enteroendocrine Cell Loss in Mice

The abdominal discomfort experienced by patients with colitis may be attributable in part to the presence of small intestinal dysmotility, yet mechanisms linking colonic inflammation with small-bowel motility remain largely unexplored. We hypothesize that colitis results in small intestinal hypomotility owing to a loss of enteroendocrine cells (EECs) within the small intestine that can be rescued using serotonergic-modulating agents. Male C57BL/6J mice, as well as mice that overexpress (EECOVER) or lack (EECDEL) NeuroD1+ enteroendocrine cells, were exposed to dextran sulfate sodium (DSS) colitis (2.5% or 5% for 7 days) and small intestinal motility was assessed by 70-kilodalton fluorescein isothiocyanate-dextran fluorescence transit. EEC number and differentiation were evaluated by immunohistochemistry, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling staining, and quantitative reverse-transcriptase polymerase chain reaction. Mice were treated with the 5-hydroxytryptamine receptor 4 agonist prucalopride (5 mg/kg orally, daily) to restore serotonin signaling. DSS-induced colitis was associated with a significant small-bowel hypomotility that developed in the absence of significant inflammation in the small intestine and was associated with a significant reduction in EEC density. EEC loss occurred in conjunction with alterations in the expression of key serotonin synthesis and transporter genes, including Tph1, Ddc, and Slc6a4. Importantly, mice overexpressing EECs revealed improved small intestinal motility, whereas mice lacking EECs had worse intestinal motility when exposed to DSS. Finally, treatment of DSS-exposed mice with the 5-hydroxytryptamine receptor 4 agonist prucalopride restored small intestinal motility and attenuated colitis. Experimental DSS colitis induces significant small-bowel dysmotility in mice owing to enteroendocrine loss that can be reversed by genetic modulation of EEC or administering serotonin analogs, suggesting novel therapeutic approaches for patients with symptomatic colitis.

Noradrenergic gene variation shaping vulnerability and resilience by affecting mental health-related characteristics: A systematic review

Mental health problems are highly prevalent worldwide. Stress can precipitate both the onset and recurrence of mental health problems. While many individuals are exposed to similar stressors, there is a large heterogeneity in sensitivity to stress and the extent to which someone subsequently develops mental health issues. A key factor that contributes to an individual's capacity to cope with adversity, referred to as resilience, is genetic variation. Here, we systematically reviewed the effects of genetic variation in the genes encoding the norepinephrine (NE) transporter and receptors on resilience- and mental health-related features in a transdiagnostic approach (i.e., without restrictions regarding factors such as diagnosis or age). Our search yielded 49 studies for inclusion. The current evidence highlights that 1) genetic variations in the NE system (particularly in the ADRA2A and ADRA2B genes) exert influence on some cognitive processes, especially attention and emotional memory; 2) genetic variants in the alpha-2a receptor might play a role in some personality traits; 3) deletion in the ADRA2B and ADRA2C genes seems to be related with altered activity of the amygdala during emotional memory tasks; 4) the link between NE variants and response to methylphenidate are inconclusive. Altogether, these studies provide evidence for a genetic effect of the noradrenergic system in specific resilience- and mental health-related individual characteristics. However, the number of available studies specifically investigating noradrenergic genes were limited, emphasizing the need to perform more research on the noradrenergic system, while taking into account factors such as age, sex, environment, and the potential interactions with other genes.

Regulation of noradrenaline synthesis, uptake, and degradation in the left ventricle by fatty acid amide hydrolase (FAAH) inhibitor URB597 in the chronic unpredictable stress model of depression

Depression has been linked to the dysfunction of the autonomic nervous system, which may cause dysregulation of the cardiovascular system. One promising therapeutic strategy for treating different diseases is inhibiting the enzyme fatty acid amide hydrolase (FAAH), which increases the availability of endogenous cannabinoids. We examined the effect of chronic FAAH inhibition with URB597 treatment on the noradrenaline (NA) content, synthesis, transport, and degradation in the left ventricle of female and male rats exposed to chronic unpredictable stress (CUS). CUS decreased the levels of both NA and dopamine-?-hydroxylase (DBH) protein in male rats and decreased NA transporter (NET) protein levels in female rats while elevating monoamine oxidase A (MAO-A) in both sexes. Intraperitoneal URB597 application led to increased expression of DBH in stressed males, as well as elevated NET protein levels and decreased MAO-A protein levels in the left ventricle of stressed rats of both sexes. URB597 treatment may have a beneficial effect on the cardiovascular system in an animal model of depression with heightened sympathoneural activity.

Investigating the Role of Serotonin Levels in Cognitive Impairments Associated with Long COVID-19.

This study aimed to investigate the activation of the inflammation process, triggered as an immune response to combat the invasion by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). SARS-CoV-2 is a highly transmissible and pathogenic coronavirus that emerged in late 2019 and has caused a pandemic of acute respiratory disease, named 'coronavirus disease 2019' (COVID-19). Several mechanisms contribute to the reduction in serotonin levels, such as the impaired absorption of dietary tryptophan, hindered serotonin transport via platelets, and increased activity of an enzyme responsible for breaking down serotonin. Individuals seeking treatment for long COVID-19 had lower serotonin levels in their blood than those who had fully recovered from the infection. Furthermore, patients with long COVID-19 also had reduced tryptophan levels. The potential benefits of dietary supplementation with tryptophan or the use of selective serotonin reuptake inhibitors (SSRIs) to improve cognitive impairments and depressive and anxiety disorders in long-term COVID-19 patients. The findings support the immune response's pivotal role in modulating serotonin levels and further highlight the intricate connection between the immune system and neurotransmitter regulation.

The association of polymorphisms of the serotonin transporter gene SLC6A4 with depression

To study the relationship of polymorphic variants of the SLC6A4 gene with depression among people aged 25-44 years in Novosibirsk. Under the WHO program «MONICA-psychosocial (MOPSY)», a random representative sample of people aged 25-44 years from the population of the Oktyabrsky district of Novosibirsk (men n=725, mean age 43.4±0.4 years, response - 71.3%, women n=710, mean age 44.8±0.4 years, response - 72%). Depression was assessed using the MONICA-MOPSY psychosocial questionnaire. Every fourth respondent was examined for polymorphic variants of 5HTTLPR-VNTR SNP rs25531 A>G of the SLC6A4 gene. The study was carried out within the framework of the budget topic Reg. No. 122031700094-5. The high level of depression among people aged 25-44 was 12.8% (for men 9.1%, for women - 15.92%); the average level of depression occurred in 24.5% of the population (among men in 21.24%, among women in 26.76%) (χ2=17.071, df=2, p<0.001). The most common genotype of the SLC6A4 gene, among people aged 25--4 years old in Novosibirsk, was SLA - 43.29%, LALA - 26.53% - in second place, SS - 17.87% - third, LALG - 6 genotypes were less represented genotypes. 74%, SLG - 4.18%, LGLG - 1.39%. Carrying the SLA genotype (53.3% and 63.6%) increased the chance of developing both the average level of depression by 2.359 (95% CI 1.278-4.355) times, and depression in general by 1.933 (95% CI 1.142-3.271) times, compared with persons carrying the LALA genotype (32.0% and 46.9%), (χ2=7.674, df=1, p<0.01 and χ2=6.095, df=1, p<0.05). Persons carrying the LALG genotype (54.5%) also had a higher chance of developing a mean level of depression RR=2.929 (95% CI 1.039-8.261), compared with carriers of the LALA genotype (32.0%) (χ2=4.326, df =1, p<0.05) (p<0.05). Associative links between polymorphic variants of the SLC6A4 gene and depression have been established.

One-drop chemosensing of dapoxetine hydrochloride using opto-analysis by multi-channel μPAD decorated silver nanoparticles: introducing a paper-based microfluidic portable device/sensor toward naked-eye pharmaceutical analysis by lab-on-paper technology.

Dapoxetine (DPX) belongs to the selective serotonin reuptake inhibitor (SSRI) class and functions by blocking the serotonin transporter and increasing serotonin activity, thereby delaying ejaculation. Therefore, monitoring of the concentration of DPX in human biofluids is important for clinicians. In this study, application of silver nanoparticles with the morphology of prisms (AgNPrs) for the sensitive measurement of DPX using colorimetric chemosensing and the spectrophotometric method was investigated. Also, DPX was determined in real samples using the spectrophotometry method. Based on the obtained results, all of the detection process in colorimetric assay is related to morphological reform of AgNPrs after it's specific electrostatic and covalent interaction with DPX as analyte. The UV-vis results indicate that the proposed AgNPrs-based chemosensing system has a wide range of linearity (0.01 μM to 1 mM) with a low limit of quantification of 0.01 μM in human urine samples, which is suitable for clinical analysis of this drug in human urine samples. It is important to point out that, this chemosensing strategy showed inappropriate analytical results for the detection of DPX in human urine samples which is a novelty of this platform. Finally, the optimized microfluidic paper-based analytical device (μPAD) was integrated with the colorimetric analysis of DPX to provide a time/color system for estimating analyte concentration by a portable substrate toward in situ and on-site biomedical analysis. Interestingly, the analytical validation tests showed appropriate results with great stability, which may facilitate commercialization of the engineered substrate. For the first time, in order to provide a simple and portable colorimetric/spectrophotometric recognition system to sensitive determination of DPX, an optimized pump-less microfluidic paper-based colorimetric device (μPCD) was introduced and validated for the real-time biomedical analysis of this analyte. According to the obtained results, this alternative approach is suitable for therapeutic drug monitoring (TDM) and biomedical analysis by miniaturized and cost-beneficial devices.

The Impact of Depression on Detrimental Changes in Bone Microstructure in Female Mice.

Several clinical studies have examined the connection between depression and bone loss, but the cause-and-effect relationship between the two conditions, especially in animal models, is not well-studied. A total of 32 female mice were, randomly divided into control group (CON, n=19) and depression group (DEP, n=13). The mice in the DEP group were subjected to 21 consecutive days of restraint stress, following depressive-like behaviors were assessment. The femurs were collected using Micro-Computed Tomography (μCT) and histochemical staining. In parallel, levels of serotonin-related proteins in the brain were measured using Western blot analysis, and sex hormone profiles were determined through liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). The mice in the DEP group exhibited clear signs of depressive-like behaviors and an increase in serotonin transporter levels (t=-2.435, P< 0.05). In comparison to the CON mice, the DEP mice showed a decrease in bone mineral density (t =3.741, P< 0.05), bone surface area density (t =8.009, P<0.01), percent bone volume (t =4.293, P< 0.05), trabecular number (t =5.844, P<0.01), and connected density (t =11.000, P< 0.05). Additionally, there was an increase in trabecular separation (t =-7.436, P<0.01) in DEP mice. Furthermore, the DEP mice displayed a significant reduction in serum estrogen levels (t =4.340, P< 0.05) and changes in its metabolite (t =-3.325, P< 0.05), while the levels of androgens remained unchanged. The restraint stress not only led to the development of depressive-like behaviors but also disrupted the estrogen metabolism pathway, resulting in damage to bone mass and microstructure in female mice. These findings suggest that stress-induced depression may pose a risk for bone loss in female mice by altering estrogen metabolism pathways.

One-pot tandem reduction and site-selective halogenation of nitroarenes.

Halogenated aryl amines are a widely used chemical feedstock in the pharmaceutical and agrochemical industries. Achieving a single regioselective product from the para-selective halogenation of the aryl ring is significantly challenging because of the presence of several C-H bonds with similar reactivities. In this study, single para-halogenated aniline derivatives were prepared by the cascade para-selective halogenation (Cl, Br) and reduction of nitrobenzene derivatives using a mixture of SnCl2/SnCl4 salts. The mechanistic study confirmed that the noncovalent interactions between the chalcogen bond and Sn salt were pivotal for achieving regioselectivity. This synthetic method was applied for the development of potent and highly selective positron emission tomography molecular probes for serotonin transporters.

Behavior Physiology of Workplace Bullying and It’s Role to Job Satisfaction and Psychologycal Distress among Workers at Water Supply Company

Individuals strive to fulfill their essential needs by working. Every company has different work environment. The work environment tends to have impact on each individual. One of the key issues that usually occur at workplace is bullying. Workplace bullying can happen to anyone while both bullies and their victims may experience psychological effects from bullying. This study aims to see the effect of workplace bullying on job satisfaction and psychological distress among water supply company employees. This research design is quantitative using cross sectional design. The results showed that the psychological distress variable played a significant role in workplace bullying (p. &lt;0.05). However, the job satisfaction variable does not contribute to workplace bullying (p. &gt; 0.05). The serotonin trasporter-linked promoter region (5-HTTLPR) polymorphism of the SLC6A4 gene consists of an insertion/deletion that creates a short (S) 14 repeat or a long (L) 16 repeat allele. Genotype profile on one’s serotonergic system is correlated by their dominance in the community. Individuals with allele LL type is more likely become bullies when they are encouraged by the environment. In contrast, individuals with SS allele type with in a characteristic of low transcription activity at transporter serotonin gene tend to become bullying victims in their workplace due to they more vulnerable to stress. Employee with amygdala which easily triggered and intimidated by the dominant individuals, more likely to experience workplace bullying. Those employee who work in supportive workplace show higher job satisfaction and they are not distress psychologically.

MAJOR DEPRESSIVE DISORDER, ENVIRONMENTAL FACTORS AND EPIGENETICS

New insights in the epigenetics have declared depression as genetic malady. For psychiatric disorders evaluation of epigenetic basis influenced by environment insults showed deeper understanding of complex multifactorial psychiatric disorder like Major depressive disorder (MDD). The World Health Organization (2008 report) has ranked MDD globally as the third cause of burden of diseases and predicted it to be the number one by 2030. Eight hallmarks of insults that lead to MDD are contaminated air, soil, food/water, ecological stressors, chemicals in households, occupational hazards as well as food/diet linked to absence of essential nutrients. Epigenetics, according to National Human Genome Research Institute, refers to changes in gene function causing their activation or deactivation without any alteration in DNA sequence. Epigenetics include histone modifications, DNA methylations, miRNAs and lncRNAs. Hypermethylation of serotonin transporter gene has been consistently found in loci encoding brain derived neurotrophic factors BDNF and SLC6A4. During pregnancy fetal epigenetic reprogramming may occur due to maternal stress and nutritional restriction. Increased cortisol or malnutrition in mothers, down-regulate cortisol enzyme, decreasing its expression in fetal cortex, making these children 4 times more at risk to stress later in life. Histones modifications including methylation and acetylation at lysine moiety during posttranslational modifications, affect neurons of CNS significantly leading to pathophysiology of MDD. Dysregulation of miRNAs and lncRNAs cause negative neural plasticity, stress responses, neurotrophic factors expression, neuroinflammation, neurotransmission, HPA axis, neurogenesis and gliogenesis and neural stem cell maintenance. Among epigenetic multifactorial disorders, psychiatric ailments have received prominence in etiology than other diseases.

DIAGNOSIS OF FIBROMYALGIA IN HEALTH PRACTICE

Fibromyalgia is a chronic non inflammatory, non-autoimmune central afferent processing disorder leading to a diffuse pain syndrome. It affects individuals of different age groups, sex and sociocultural background. It is estimated to affect 2-5% of western population. The symptoms include widespread pain, fatigue, stiffness and sleep disturbance, cognitive problems and mood disorders (anxiety, depression or both) 1. The etiology of Fibromyalgia (FM) is unknown; however several factors may contribute to development as well as severity of symptoms of FM. Genetic polymorphisms have been reported in serotonin transporter and receptors, as well as in dopamine, beta2 adrenergic and glutamate receptor genes. 2 Middle aged women and young are more affected. Sleep abnormalities, autonomic dysregulation, and psychological variables like perfectionist personality, negative beliefs, low self-esteem, depression and anxiety are the contributory factors.3 Physical examination and pathological investigations reveal no evidence of articular, osseous or soft tissue inflammation or degeneration. Patients may have tender points both above and below the waist. The previously followed criteria, depending on presence of tender points, are no more followed. In 2010, a new diagnostic criterion was adopted by American College of Rheumatology (ACR) 4. It has three points: - 1. Widespread pain index (WPI)&gt;7 &amp; a symptom severity (SS) score &gt;5 or widespread pain index 3-6 &amp; (SS) score &gt;9. 2. Symptoms present for at least 3.No other disorder to explain In differential diagnosis, many diseases need to be ruled out making the diagnosis of FM. These are systemic lupus erythematosis, systemic sclerosis, polymyositis, ankylosing spondylitis, osteomalacia, rheumatoid arthritis, polymyalgia rheumatic hypothyroidism, chronic hepatitis, HIV, hemo- chromatosis, celiac disease, myasthenia gravis, hyperthyroidism, myopathies, Sjogren`s, adrenal insufficiency, lymphoma and chronic fatigue syndrome.5 Although the exact pathophysiology of FM is unknown, most of the researchers believe that the pathophysiology of FM is due to the central sensitization within the CNS, manifesting as amplified pain perception. The specific abnormalities that have been observed in the afferent pain procession areas of the CNS in FM patients, who exhibit the following symptoms: increased excitability of dorsal horn nuclei due to abnormal windup; increased levels of substance P, nerve growth factor, glutamate and aspartate measured in CSF of patients with FM 6expanded receptive fields for central pain perception (central sensitization); MRI shows expanded fields in the insula, anterior cingulate cortex and somatosensory area.7 The abnormalities within the descending analgesia system are also observed i.e decreased levels of pain inhibitory neurotransmitters including nor epinephrine, serotonin, dopamine and suppression of normal activity of dopamine releasing neurons in limbic system.1 The management of FM is very challenging. It has many components i.e patient education, physical exercises, analgesia, treatment of associated condition like anxiety, depression, and mood disorders. Counseling about the disease and CBT are also helpful. Medication approved for the treatment of FM are: Serotonin-noreprenphine reuptake inhibitors (SNRIs); Duloxetine ,venlaxafine, Milnacipran. Anticonvulsants; Pregabalin. Tri cyclic antidepressants: Amitriptyline, imipramine. Analgesia; Tramadol. Paracetamol and NSAIDS are not affective for analgesia.8,9 The diagnosis of FM is quiet challenging in the developed world with good evaluation and referral system. In underdeveloped country with poor medical education and no referral system FM patients are the mostly go un-diagnosed and hence are under treated. It is high time to highlight the importance of diagnosis of FM by the general practitioner and other specialties doctors for proper management of these patients. The disease impact of FM is not less than any other chronic inflammatory disease like Rheumatoid Arthritis. On an average the FM patients visit doctor 3-4 times more often than the general population (17 versus 4 visits/year). The frequent visits of patients with FM, is one of the factors of increasing burden on health system as well as having socio-economic impact on patients.

Long-term administration of probiotics prevents gastrointestinal mucosal barrier dysfunction in septic mice partly by upregulating the 5-HT degradation pathway.

Sepsis can impair gastrointestinal (GI) barrier integrity. Oral probiotics (PT) can maintain the balance of GI microflora and improve GI function. 5-Hydroxytryptamine (5-HT) is a key promoter of GI injury caused by sepsis. However, the mechanism by which PT attenuates sepsis by regulating 5-HT is not fully understood. In this study, C57BL6 mice were intragastric administrated with normal saline (NC) or PT once a day for 4 weeks before cecal ligation and puncture (CLP). Compared with NC-CLP mice, PT-CLP mice had lower clinical score, higher body temperature. The survival rate of PT-CLP mice was significantly improved. The levels of inflammatory cytokines and 5-HT were obviously decreased in PT-CLP mice, and GI peristalsis and barrier function were enhanced. Moreover, sepsis downregulated the expression of tight junction proteins, while PT pretreatment could maintain them at the level of sham operation group. Furthermore, PT pretreatment increased the expression of serotonin transporter and monoamine oxidase A. PT administration could inhibit NF-κB activity, and activate ERK activity. In conclusion, long-term supplementation of PT before CLP can prevent sepsis-induced GI mucosal barrier dysfunction in mice, which may be partially mediated by upregulating the 5-HT degradation pathway via activating ERK signaling.

Molecular Dynamics Simulation of Serotonin Transport Protein Complex with 6-Hydroxy-1-Methyl-1,2,3,4-Tetrahydro-β-Carboline Ligand from Chocolate (Theobroma cacao L.) Isolate

6-hydroxy-1-methyl1,2,3,4-tetrahydro-β-carboline (6OHMTHβC) is a chocolate derivate that has antidepressant potency. It can increase dopamine and serotonin secretion, which leads to mood improvement. This method was carried out using computational molecular docking simulations (in silico). The research design was computational-based exploratory descriptive. The results of molecular docking showed the lowest energy score and the backbone RMSD value ≤2Å. The procedure performed was 6AWP receptor docking without ligand, with native ligand (6OHMTHβC), and with reference ligand (fluvoxamine). This study also performed molecular docking simulations of 6OHMTHβC towards 6AWP to find compounds in the receptor binding pocket. This study also performed dynamics simulations and identified the molecular determinants using PyPLIF-HIPPOS and YASARA Structure software 20.1.24.10 with the Windows 10 operating system. This study succeeded in determining the stability of the dynamics simulation of the serotonin transport protein complex with the reference ligand 6OHMTHβC for 50 ns, and this result corresponds to the RMSD value and binding energy. The determination of binding energy (BE) was calculated from the BE calculation available at YASARA and Ubuntu. The binding energy value of the original ligand was -11.6590 kJ/mol, and the reference ligand was -83880 kJ/mol. The highest RMSD value of the original ligand was 1.39292Å, while the RMSD value of the reference ligand was 1.71072Å. The essential amino acid carried out was 438Ser with hydrogen bond interactions, so 6OHMTHβC was considered a competent antidepressant candidate.

Modifications to 1-(4-(2-Bis(4-fluorophenyl)methyl)sulfinyl)alkyl Alicyclic Amines That Improve Metabolic Stability and Retain an Atypical DAT Inhibitor Profile.

Atypical dopamine transporter (DAT) inhibitors have shown therapeutic potential in the preclinical models of psychostimulant use disorders (PSUD). In rats, 1-(4-(2-((bis(4-fluorophenyl)methyl)sulfinyl)ethyl)-piperazin-1-yl)-propan-2-ol (JJC8-091, 3b) was effective in reducing the reinforcing effects of both cocaine and methamphetamine but did not exhibit psychostimulant behaviors itself. Improvements in DAT affinity and metabolic stability were desirable for discovering pipeline drug candidates. Thus, a series of 1-(4-(2-bis(4-fluorophenyl)methyl)sulfinyl)alkyl alicyclic amines were synthesized and evaluated for binding affinities at DAT and the serotonin transporter (SERT). Replacement of the piperazine with either a homopiperazine or a piperidine ring system was well tolerated at DAT (Ki range = 3-382 nM). However, only the piperidine analogues (20a-d) showed improved metabolic stability in rat liver microsomes as compared to the previously reported analogues. Compounds 12b and 20a appeared to retain an atypical DAT inhibitor profile, based on negligible locomotor activity in mice and molecular modeling that predicts binding to an inward-facing conformation of DAT.

Abnormal interhemispheric functional cooperation in schizophrenia follows the neurotransmitter profiles.

Interhemispheric cooperation is one of the most prominent functional architectures of the human brain. In patients with schizophrenia, interhemispheric cooperation deficits have been reported using increasingly powerful neurobehavioural and neuroimaging measures. However, these methods rely in part on the assumption of anatomic symmetry between hemispheres. In the present study, we explored interhemispheric cooperation deficits in schizophrenia using a newly developed index, connectivity between functionally homotopic voxels (CFH), which is unbiased by hemispheric asymmetry. Patients with schizophrenia and age- and sexmatched healthy controls underwent multimodal MRI, and whole-brain CFH maps were constructed for comparison between groups. We examined the correlations of differing CFH values between the schizophrenia and control groups using various neurotransmitter receptor and transporter densities. We included 86 patients with schizophrenia and 86 matched controls in our analysis. Patients with schizophrenia showed significantly lower CFH values in the frontal lobes, left postcentral gyrus and right inferior temporal gyrus, and significantly greater CFH values in the right caudate nucleus than healthy controls. Moreover, the differing CFH values in patients with schizophrenia were significantly correlated with positive symptom score and illness duration. Functional connectivity within frontal lobes was significantly reduced at the voxel cluster level compared with healthy controls. Finally, the abnormal CFH map of patients with schizophrenia was spatially associated with the densities of the dopamine D1 and D2 receptors, fluorodopa, dopamine transporter, serotonin transporter and acetylcholine transporter. Regional abnormalities in interhemispheric cooperation may contribute to the clinical symptoms of schizophrenia. These CFH abnormalities may be associated with dysfunction in neurotransmitter systems strongly implicated in schizophrenia.

Monoaminergic network dysfunction and development of depression in multiple sclerosis: a longitudinal investigation.

Monoaminergic network dysfunction is thought to underpin depression in multiple sclerosis (MS) patients. However, longitudinal studies are lacking. Here, we investigated the association between development of depressive symptoms in MS and changes of resting-state functional connectivity (RS FC) within monoaminergic networks. Forty-nine MS patients without depression [Montgomery-Asberg Depression Scale (MADRS) ≤ 9] and 27 healthy controls underwent clinical and 3.0T RS FC assessment at baseline and after a median follow-up of 1.6years (interquartile range 1.0-2.1years). Monoamine-related RS FC was derived by independent component analysis, constrained to PET atlases for dopamine, noradrenaline and serotonin transporters. Longitudinal changes of RS FC within monoaminergic networks and their correlations with MADRS scores were assessed. At baseline, MS patients showed decreased RS FC vs healthy controls in all PET-guided monoaminergic networks in frontal, cingulate and cerebellar cortices, and increased RS FC in parieto-occipital regions. Fourteen (29%) MS patients developed depressive symptoms (MADRS > 9) at follow-up (D-MS) and exhibited widespread RS FC decrease over time in the PET-guided dopamine network, mainly in orbitofrontal, occipital, anterior cingulate and precuneal cortices compared to patients who did not develop depressive symptoms. In D-MS, decreased RS FC over time was also observed in parahippocampal and occipital regions of the PET-guided noradrenaline network. Decreased RS FC over time in dopamine and noradrenaline PET-guided networks correlated with concomitant increased MADRS scores (r = range - 0.65/- 0.61, p < 0.001). The development of depressive symptoms in MS patients was associated with specific RS FC changes within the dopamine and noradrenaline networks.

Biomarkers of Affective Dysregulation Associated with In Utero Exposure to EtOH.

Children with fetal alcohol spectrum disorders (FASD) exhibit behavioral and affective dysregulation, including hyperactivity and depression. The mechanisms are not known, but they could conceivably be due to postnatal social or environmental factors. However, we postulate that, more likely, the affective dysregulation is associated with the effects of EtOH exposure on the development of fetal serotonergic (5-HT) and/or dopaminergic (DA) pathways, i.e., pathways that in postnatal life are believed to regulate mood. Many women who use alcohol (ethanol, EtOH) during pregnancy suffer from depression and take selective serotonin reuptake inhibitors (SSRIs), which might influence these monoaminergic pathways in the fetus. Alternatively, monoaminergic pathway abnormalities might reflect a direct effect of EtOH on the fetal brain. To distinguish between these possibilities, we measured their expressions in fetal brains and in fetal brain-derived exosomes (FB-Es) isolated from the mothers' blood. We hypothesized that maternal use of EtOH and/or SSRIs during pregnancy would be associated with impaired fetal neural development, detectable as abnormal levels of monoaminergic and apoptotic biomarkers in FB-Es. Fetal brain tissues and maternal blood were collected at 9-23 weeks of pregnancy. EtOH groups were compared with unexposed controls matched for gestational age (GA). The expression of 84 genes associated with the DA and 5-HT pathways was analyzed by quantitative reverse transcription polymerase chain reaction (qRT-PCR) on microarrays. FB-Es also were assayed for serotonin transporter protein (SERT) and brain-derived neurotrophic factor (BDNF) by enzyme-linked immunosorbent assay (ELISA). Six EtOH-exposed human fetal brain samples were compared to SSRI- or polydrug-exposed samples and to unexposed controls. EtOH exposure was associated with significant upregulation of DA receptor D3 and 5-HT receptor HTR2C, while HTR3A was downregulated. Monoamine oxidase A (MAOA), MAOB, the serine/threonine kinase AKT3, and caspase-3 were upregulated, while mitogen-activated protein kinase 1 (MAPK1) and AKT2 were downregulated. ETOH was associated with significant upregulation of the DA transporter gene, while SERT was downregulated. There were significant correlations between EtOH exposure and (a) caspase-3 activation, (b) reduced SERT protein levels, and (c) reduced BDNF levels. SSRI exposure independently increased caspase-3 activity and downregulated SERT and BDNF. Early exposure to EtOH and SSRI together was associated synergistically with a significant upregulation of caspase-3 and a significant downregulation of SERT and BDNF. Reduced SERT and BDNF levels were strongly correlated with a reduction in eye diameter, a somatic manifestation of FASD. Maternal use of EtOH and SSRI during pregnancy each was associated with changes in fetal brain monoamine pathways, consistent with potential mechanisms for the affective dysregulation associated with FASD.

Mild internet use is associated with epigenetic alterations of key neurotransmission genes in salivary DNA of young university students

The potentially problematic use of the Internet is a growing concern worldwide, which causes and consequences are not completely understood yet. The neurobiology of Internet addiction (IA) has attracted much attention in scientific research, which is now focusing on identifying measurable biological markers. Aim of this study was to investigate epigenetic and genetic regulation of oxytocin receptor (OXTR), dopamine transporter (DAT1) and serotonin transporter (SERT) genes using DNA obtained from saliva samples of young university students: the Internet Addiction Test (IAT) was administered to evaluate the potential existence and intensity of IA. Significant changes in DNA methylation levels at OXTR, DAT1 and SERT genes were observed in the 30 < IAT < 49 group (mild-risk internet users) compared to the IAT < 29 subjects (complete control of internet use) and IAT > 50 subjects (considered as moderately addicted). Moreover, epigenetic markers were significantly correlated, either directly (for OXTR and DAT1) or inversely (OXTR and DAT1 versus SERT), to the psychometric properties. Our data confirmed the association of OXTR, DAT1 and SERT genes in processes related to behavioural addictions and might be of relevance to suggest possible biological predictors of altered behaviours and the eventual vulnerability to develop an IA. Different other genetic pathways have been suggested to play a role in IA and research is ongoing to better define them, in order to help in the early diagnosis as well as in the development of new potential treatments.

Maternal exposure to bisphenol S reduces anxiety and impairs collective antipredator behavior of male zebrafish (Danio rerio) offspring through dysregulation of their serotonergic system

Bisphenol S (BPS) is a common endocrine-disrupting chemical globally used in several consumer and industrial products. Although previous studies suggested that BPS induces multiple effects in exposed organisms, very little is known about its intergenerational effect on offspring behavior and/or the potential underlying mechanisms. To this end, adult female zebrafish Danio rerio were exposed to BPS (0, 10, 30 µg/L) and 1 µg/L of 17-β-estradiol (E2) as a positive control for 60 days. Afterwards, female fish were bred with untreated males, and their offspring were raised to 6 months old in control water. Maternal exposure to BPS decreased male offspring anxiety and antipredator behaviors while boldness remained unaffected. Specifically, maternal exposure to 10 and 30 µg/L BPS and 1 µg/L E2 were found to impact male offspring anxiety levels as they decreased the total time that individuals spent in the dark zone in the light/dark box test and increased the total track length in the center of the open field test. In addition, maternal exposure to all concentrations of BPS and E2 disrupted antipredator responses of male offspring by decreasing shoal cohesion in the presence of chemical alarm cues derived from conspecifics, which communicated high risk. To elucidate the possible molecular mechanism underlying these neuro-behavioral effects of BPS, we assessed the serotonergic system via changes in mRNA expression of serotonin receptors, including the 5-HT1A, 5-HT1B, and 5-HT1D subtypes, the serotonin transporter and monoamine oxidase (MAO). The impaired anxiety and antipredator responses were associated with reduced levels of 5-HT1A subtype and MAO mRNA expression within the brain of adult male offspring. Collectively, the results of this study demonstrate that maternal exposure to environmental concentrations of BPS can interfere with the serotonergic signaling pathway in the developing brain, subsequently leading to the onset of a suite of behavioral deficits in adult offspring.

DNA methylation levels of the serotonin transporter gene are not associated with the outcome of highly standardized one-session exposure-based fear treatment

Epigenetic alterations are regarded as a potential mechanism mediating the effects of environmental risk factors on vulnerability for a range of mental health problems. Recent studies have addressed the question whether DNA methylation patterns predict the outcome of psychological interventions and whether treatment effects might be associated with changes of DNA methylation. We assessed phobic fear symptoms, treatment-relevant traits and treatment response in 308 adults free of psychotropic medication - highly fearful of either spiders, blood-injury-injections, dental-treatments or heights - all subjected to highly standardized exposure-based one-session fear treatment. DNA methylation level of the promotor region of the serotonin transporter gene (SLC6A4) was assessed in either saliva samples (spider and dental treatment fear cohorts) or oral mucosa (BII, heights) to check whether possible effects are independent of the surrogate tissue examined. Moreover, in order to examine possible DNA methylation by genotype effects, patients were assessed for genetic variation of the serotonin transporter-linked polymorphic region (5-HTTLPR). DNA methylation levels were neither associated with pre-treatment fear levels, treatment relevant traits or treatment outcome data even when allelic variation of the 5HTTLPR was considered. Overall DNA methylation levels were higher in saliva samples compared to buccal samples. In saliva samples there was a small pre- to post-treatment increase in DNA methylation, which, however, was also not associated with the investigated phenotypes. We conclude that DNA methylation of SLC6A4 is no suitable biomarker for response efficacy to highly standardized one-session exposure-based fear treatments.