Unlocking the biosynthesis of psychedelic-inspired indolethylamines.

A recent report by Chen et al. describes the discovery of RmNMT, a highly active and promiscuous tryptamine N-methyltransferase from the cane toad, Rhinella marina. N,N-dimethyltryptamine derivatives produced by this enzyme were then evaluated for their potential to serve as next-generation treatments for mental health disorders.

The Effects of Psychedelics on Neuronal Physiology.

Psychedelics are quite unique among drugs that impact the central nervous system, as a single administration of a psychedelic can both rapidly alter subjective experience in profound ways and produce sustained effects on circuits relevant to mood, fear, reward, and cognitive flexibility. These remarkable properties are a direct result of psychedelics interacting with several key neuroreceptors distributed across the brain. Stimulation of these receptors activates a variety of signaling cascades that ultimately culminate in changes in neuronal structure and function. Here, we describe the effects of psychedelics on neuronal physiology, highlighting their acute effects on serotonergic and glutamatergic neurotransmission as well as their long-lasting effects on structural and functional neuroplasticity in the cortex. We propose that the neurobiological changes leading to the acute and sustained effects of psychedelics might be distinct, which could provide opportunities for engineering compounds with optimized safety and efficacy profiles.

Neurobiological research on N,N-dimethyltryptamine (DMT) and its potentiation by monoamine oxidase (MAO) inhibition: from ayahuasca to synthetic combinations of DMT and MAO inhibitors.

The potent hallucinogen N,N-dimethyltryptamine (DMT) has garnered significant interest in recent years due to its profound effects on consciousness and its therapeutic psychopotential. DMT is an integral (but not exclusive) psychoactive alkaloid in the Amazonian plant-based brew ayahuasca, in which admixture of several ß-carboline monoamine oxidase A (MAO-A) inhibitors potentiate the activity of oral DMT, while possibly contributing in other respects to the complex psychopharmacology of ayahuasca. Irrespective of the route of administration, DMT alters perception, mood, and cognition, presumably through agonism at serotonin (5-HT) 1A/2A/2C receptors in brain, with additional actions at other receptor types possibly contributing to its overall psychoactive effects. Due to rapid first pass metabolism, DMT is nearly inactive orally, but co-administration with ß-carbolines or synthetic MAO-A inhibitors (MAOIs) greatly increase its bioavailability and duration of action. The synergistic effects of DMT and MAOIs in ayahuasca or synthetic formulations may promote neuroplasticity, which presumably underlies their promising therapeutic efficacy in clinical trials for neuropsychiatric disorders, including depression, addiction, and post-traumatic stress disorder. Advances in neuroimaging techniques are elucidating the neural correlates of DMT-induced altered states of consciousness, revealing alterations in brain activity, functional connectivity, and network dynamics. In this comprehensive narrative review, we present a synthesis of current knowledge on the pharmacology and neuroscience of DMT, ß-carbolines, and ayahuasca, which should inform future research aiming to harness their full therapeutic potential.

Oral iron therapy: Current concepts and future prospects for improving efficacy and outcomes.

Iron deficiency (ID) and iron-deficiency anaemia (IDA) are global public health concerns, most commonly afflicting children, pregnant women and women of childbearing age. Pathological outcomes of ID include delayed cognitive development in children, adverse pregnancy outcomes and decreased work capacity in adults. IDA is usually treated by oral iron supplementation, typically using iron salts (e.g. FeSO4 ); however, dosing at several-fold above the RDA may be required due to less efficient absorption. Excess enteral iron causes adverse gastrointestinal side effects, thus reducing compliance, and negatively impacts the gut microbiome. Recent research has sought to identify new iron formulations with better absorption so that lower effective dosing can be utilized. This article outlines emerging research on oral iron supplementation and focuses on molecular mechanisms by which different supplemental forms of iron are transported across the intestinal epithelium and whether these transport pathways are subject to regulation by the iron-regulatory hormone hepcidin.

Knockdown of microglial iron import gene, Slc11a2, worsens cognitive function and alters microglial transcriptional landscape in a sex-specific manner in the APP/PS1 model of Alzheimer's disease.

BACKGROUND: Microglial cell iron load and inflammatory activation are significant hallmarks of late-stage Alzheimer's disease (AD). In vitro, microglia preferentially upregulate the iron importer, divalent metal transporter 1 (DMT1, gene name Slc11a2) in response to inflammatory stimuli, and excess iron can augment cellular inflammation, suggesting a feed-forward loop between iron import mechanisms and inflammatory signaling. However, it is not understood whether microglial iron import mechanisms directly contribute to inflammatory signaling and chronic disease in vivo. These studies determined the effects of microglial-specific knockdown of Slc11a2 on AD-related cognitive decline and microglial transcriptional phenotype. METHODS: In vitro experiments and RT-qPCR were used to assess a role for DMT1 in amyloid-ß-associated inflammation. To determine the effects of microglial Slc11a2 knockdown on AD-related phenotypes in vivo, triple-transgenic Cx3cr1Cre-ERT2;Slc11a2flfl;APP/PS1+or - mice were generated and administered corn oil or tamoxifen to induce knockdown at 5-6 months of age. Both sexes underwent behavioral analyses to assess cognition and memory (12-15 months of age). Hippocampal CD11b+ microglia were magnetically isolated from female mice (15-17 months) and bulk RNA-sequencing analysis was conducted. RESULTS: DMT1 inhibition in vitro robustly decreased Aß-induced inflammatory gene expression and cellular iron levels in conditions of excess iron. In vivo, Slc11a2KD APP/PS1 female, but not male, mice displayed a significant worsening of memory function in Morris water maze and a fear conditioning assay, along with significant hyperactivity compared to control WT and APP/PS1 mice. Hippocampal microglia from Slc11a2KD APP/PS1 females displayed significant increases in Enpp2, Ttr, and the iron-export gene, Slc40a1, compared to control APP/PS1 cells. Slc11a2KD cells from APP/PS1 females also exhibited decreased expression of markers associated with subsets of disease-associated microglia (DAMs), such as Apoe, Ctsb, Ly9, Csf1, and Hif1α. CONCLUSIONS: This work suggests a sex-specific role for microglial iron import gene Slc11a2 in propagating behavioral and cognitive phenotypes in the APP/PS1 model of AD. These data also highlight an association between loss of a DAM-like phenotype in microglia and cognitive deficits in Slc11a2KD APP/PS1 female mice. Overall, this work illuminates an iron-related pathway in microglia that may serve a protective role during disease and offers insight into mechanisms behind disease-related sex differences.

Iron deficiency in astrocytes alters cellular status and impacts on oligodendrocyte differentiation.

Iron deficiency (ID) has been shown to affect central nervous system (CNS) development and induce hypomyelination. Previous work from our laboratory in a gestational ID model showed that both oligodendrocyte (OLG) and astrocyte (AST) maturation was impaired. To explore the contribution of AST iron to the myelination process, we generated an in vitro ID model by silencing divalent metal transporter 1 (DMT1) in AST (siDMT1 AST) or treating AST with Fe3+ chelator deferoxamine (DFX; DFX AST). siDMT1 AST showed no changes in proliferation but remained immature. Co-cultures of oligodendrocyte precursors cells (OPC) with siDMT1 AST and OPC cultures incubated with siDMT1 AST-conditioned media (ACM) rendered a reduction in OPC maturation. These findings correlated with a decrease in the expression of AST-secreted factors IGF-1, NRG-1, and LIF, known to promote OPC differentiation. siDMT1 AST also displayed increased mitochondrial number and reduced mitochondrial size as compared to control cells. DFX AST also remained immature and DFX AST-conditioned media also hampered OPC maturation in culture, in keeping with a decrease in the expression of AST-secreted growth factors IGF-1, NRG-1, LIF, and CNTF. DFX AST mitochondrial morphology and number showed results similar to those observed in siDMT1 AST. In sum, our results show that ID, induced through two different methods, impacts AST maturation and mitochondrial functioning, which in turn hampers OPC differentiation.

Microglial-specific knockdown of iron import gene, Slc11a2, blunts LPS-induced neuroinflammatory responses in a sex-specific manner.

Neuroinflammation and microglial iron load are significant hallmarks found in several neurodegenerative diseases. In in vitro systems, microglia preferentially upregulate the iron importer, divalent metal transporter 1 (DMT1, gene name Slc11a2) in response to inflammatory stimuli, and it has been shown that iron can augment cellular inflammation, suggesting a feed-forward loop between mechanisms involved in iron import and inflammatory signaling. However, it is not understood how microglial iron import mechanisms contribute to inflammation in vivo, or whether altering a microglial iron-related gene affects the inflammatory response. These studies aimed to determine the effect of knocking down microglial iron import gene Slc11a2 on the inflammatory response in vivo. We generated a novel model of tamoxifen-inducible, microglial-specific Slc11a2 knockdown using Cx3cr1Cre-ERT2 mice. Transgenic male and female mice were administered intraperitoneal saline or lipopolysaccharide (LPS) and assessed for sickness behavior post-injection. Plasma cytokines and microglial bulk RNA sequencing (RNASeq) analyses were performed at 4 h post-LPS, and microglia were collected for gene expression analysis after 24 h. A subset of mice was assessed in a behavioral test battery following LPS-induced sickness recovery. Control male, but not female, mice significantly upregulated microglial Slc11a2 at 4 and 24 h following LPS. In Slc11a2 knockdown mice, we observed an improvement in the acute behavioral sickness response post-LPS in male, but not female, animals. Microglia from male, but not female, knockdown animals exhibited a significant decrease in LPS-provoked pro-inflammatory cytokine expression after 24 h. RNASeq data from male knockdown microglia 4 h post-LPS revealed a robust downregulation in inflammatory genes including Il6, Tnfα, and Il1ß, and an increase in anti-inflammatory and homeostatic markers (e.g., Tgfbr1, Cx3cr1, and Trem2). This corresponded with a profound decrease in plasma pro-inflammatory cytokines 4 h post-LPS. At 4 h, male knockdown microglia also upregulated expression of markers of iron export, iron recycling, and iron homeostasis and decreased iron storage and import genes, along with pro-oxidant markers such as Cybb, Nos2, and Hif1α. Overall, this work elucidates how manipulating a specific gene involved in iron import in microglia alters acute inflammatory signaling and overall cell activation state in male mice. These data highlight a sex-specific link between a microglial iron import gene and the pro-inflammatory response to LPS in vivo, providing further insight into the mechanisms driving neuroinflammatory disease.

Significantly increasing multiple sclerosis prevalence in Australia from 2010 to 2021.

BACKGROUND: Multiple sclerosis (MS) prevalence is increasing globally. OBJECTIVES: To determine whether increased prevalence is continuing within Australia using our validated prescription-based ascertainment method. METHODS: We used methods employed in our 2010 and 2017 prevalence estimates. Disease-modifying therapy (DMT) prescriptions were extracted from Australia's Pharmaceutical Benefits Scheme data for January-December 2021. DMT penetrance was calculated using data from the Australian MS Longitudinal Study. We divided the total number of monthly prescriptions by 12 or 2 (except alemtuzumab), adjusted for DMT penetrance and Australian population estimates. Prevalences in Australian states/territories were age-standardised. 2021 prevalence estimates were compared with 2010 and 2017 prevalence estimates using Poisson regression. RESULTS: Number of people with MS in Australia in 2021 was 33,335; an increase of 7728 from 2017 (30.2%) and 12,092 from 2010 (56.6%) and increasing at a faster rate than population change (+10.1%, +14.1%). Age-standardised prevalence was 136.1/100,000 (increased from 103.7/100,000 in 2017). The previously demonstrated positive latitudinal gradient in 2010 and 2017 persisted in 2021, with Tasmania (southernmost state) having the highest prevalence (age-standardised: 203.5/100,000) while northernmost states had the lowest. CONCLUSIONS: In line with global trends, MS prevalence is escalating in Australia, particularly in higher-latitude states. MS prevention is crucial to halt this disturbing trend.

Mind over matter: the microbial mindscapes of psychedelics and the gut-brain axis.

Psychedelics have emerged as promising therapeutics for several psychiatric disorders. Hypotheses around their mechanisms have revolved around their partial agonism at the serotonin 2 A receptor, leading to enhanced neuroplasticity and brain connectivity changes that underlie positive mindset shifts. However, these accounts fail to recognise that the gut microbiota, acting via the gut-brain axis, may also have a role in mediating the positive effects of psychedelics on behaviour. In this review, we present existing evidence that the composition of the gut microbiota may be responsive to psychedelic drugs, and in turn, that the effect of psychedelics could be modulated by microbial metabolism. We discuss various alternative mechanistic models and emphasize the importance of incorporating hypotheses that address the contributions of the microbiome in future research. Awareness of the microbial contribution to psychedelic action has the potential to significantly shape clinical practice, for example, by allowing personalised psychedelic therapies based on the heterogeneity of the gut microbiota.

De-escalation and Discontinuation of Disease-Modifying Therapies in Multiple Sclerosis.

PURPOSE OF REVIEW: Long-term use of multiple sclerosis (MS) disease-modifying therapies (DMTs) is standard practice to prevent accumulation of disability. Immunosenescence and other age-related changes lead to an altered risk-benefit ratio for older patients on DMTs. This article reviews recent research on the topic of de-escalation and discontinuation of MS DMTs. RECENT FINDINGS: Observational and interventional studies have shed light on what happens to patients who de-escalate or discontinue DMTs and the factors, such as age, treatment type, and presence of recent disease activity, that influence outcomes. Though many questions remain, recent findings have been valuable for the development of an evidence-based approach to making de-escalation and discontinuation decisions in MS.

Correlation between MRI utilization and therapy switches in disease-modifying treatments for multiple sclerosis.

BACKGROUND AND OBJECTIVES: Studies measuring the role of magnetic resonance imaging (MRI) in therapeutic decision-making are rare in people with multiple sclerosis (pwMS). This study aimed to measure the association between MRI utilization and disease-modifying therapy (DMT) switches in pwMS. METHODS: This retrospective cohort study identified pwMS in 2018 from a de-identified national claims database. PwMS who received MRI in 2018 were compared to pwMS not receiving MRI in 2018. PwMS were observed for six months to assess the incidence of DMT switches. RESULTS: The study sample consisted of 11,972 pwMS. 3,931 (32.8%) pwMS received at least one MRI in 2018. Overall, MRI utilization increased the odds of switching DMT (OR = 1.49, 1.79, and 3.01 for 1, 2, and ≥ 3 CNS locations imaged). For those on injectable or platform DMT, any MRI utilization increased the odds of switching DMT (OR = 1.54, 2.00, and 3.48 for 1, 2, and ≥ 3 locations imaged). For those on oral DMT, only receiving MRI of 2 or ≥ 3 locations increased the odds of a DMT switch (OR = 1.36, 1.89, and 2.40 for 1, 2, and ≥ 3 locations). Finally, for pwMS on infusible therapies, there was little evidence that MRI changed the odds of a DMT switch. DISCUSSION: Among pwMS on injectable or oral DMT, imaging more CNS locations increased the odds of switching DMT after adjusting for age and relapse incidence. For pwMS on high-efficacy infusible DMTs, MRI did not change the odds of switching DMT but remains essential for safety monitoring.

The changing outlook of psychedelic drugs: The importance of risk assessment and occupational exposure limits.

Serotonergic psychedelics, such as lysergic acid diethylamide (LSD), psilocybin, dimethyltryptamine (DMT), and 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT), are currently being investigated for the treatment of psychiatric disorders such as depression and anxiety. Clinical trials with psilocybin and LSD have shown improvement in emotional and psychological scores. Although these drugs are reported to be safe in a controlled environment (such as clinical trials), exposure to low doses of these drugs can result in psychedelic effects, and therefore, occupational safety is an important consideration to prevent adverse effects in the workplace from low daily exposure. This article will discuss the factors involved in the derivation of occupational exposure limits (OELs) and risk assessment of these psychedelic drugs. To support the OEL derivations of psychedelic drugs, information regarding their mechanism of action, adverse effect profiles, pharmacokinetics, clinical effects, and nonclinical toxicity were considered. Additionally, psilocybin and LSD, which are the most extensively researched psychedelic substances, are employed as illustrative examples in case studies. The OELs derived for psilocybin and for LSD are 0.05 and 0.002 µg/m3 , respectively, which indicates that these are highly hazardous compounds, and it is important to take into account suitable safety measures and risk-management strategies in order to minimize workplace exposure.

Association between maternal iron status and the risk of pre-eclampsia: a case-control study.

BACKGROUND AND OBJECTIVES: This study aimed to assess the associations of maternal iron status and placental iron transport proteins expression with the risk of pre-eclampsia (PE) in Chinese pregnant women. METHODS AND STUDY DESIGN: A total of 94 subjects with PE and 112 healthy pregnant women were enrolled. Fasting blood samples were collected to detect maternal iron status. The placenta samples were collected at delivery to detect the mRNA and protein expression of divalent metal transporter 1 (DMT1) and ferroportin-1 (FPN1). Logistic analysis was used to explore the associations of maternal iron status with PE risk. The associations of placental iron transport proteins with maternal iron status were explored. RESULTS: After adjusting for covariates, dietary total iron, non-heme iron intake and serum hepcidin were negatively associated with PE, with adjusted ORs (95%CIs) were 0.40 (0.17, 0.91), 0.42 (0.18, 0.94) and 0.02 (0.002, 0.13) for the highest versus lowest tertile, respectively. For the highest tertile versus lowest tertile, serum iron (4.08 (1.58, 10.57)) and ferritin (5.61 (2.36, 13.31)) were positively associated with PE. The mRNA expressions and protein levels of DMT1 and FPN1 in placenta were up-regulated in the PE group (p < 0.05). The mRNA expressions of DMT1 and FPN1 in placenta showed a negative correlation with the serum hepcidin (r = -0.71, p < 0.001; r = -0.49, p < 0.05). CONCLUSIONS: In conclusion, the maternal iron status were closely associated with PE risk, placental DMT1 and FPN1 were upregulated in PE which may be a promising target for the prevention of PE.

[Neuroimaging correlates of classical psychedelics effects: A systematic review]. / Corolaires en neuro-imagerie des effets des psychédéliques classiques : une revue systématique de la littérature.

BACKGROUND: Current scientific literature supports classical psychedelic efficacy in many psychiatric disorders. However, less attention has been given to the neurological effects of these substances. The aim of this medical thesis was to conduct a systematic review examining the neuroimaging correlates of the effects of psychedelics. METHOD: We performed an electronic research through Medline and Science Direct databases. A comprehensive search yielded 460 articles published up to May 2022. After a cautious screening process, we selected 49 scientific papers for further analysis. RESULTS: Major findings included reduced functional network integration, increased between-network functional connectivity, and expansion of functional connectivity patterns repertoire under psychedelics. Thalamic gating and emotional processing were also impaired. These results positively correlated with symptom improvement in pathological populations. CONCLUSION: To this day, our knowledge concerning psychedelic effects remains partial. Several neurocognitive theories have been developed in recent years to model psychedelic phenomenology, but no unifying theory has emerged. Studies involving larger populations investigating various psychiatric disorders, including several neuroimaging modalities and considering medium- and long-term effects, would be necessary to deepen current knowledge.

Iron from the gut: the role of divalent metal transporter 1.

Mammalian cells contain thousands of metalloproteins and evolved systems to correctly incorporate metal cofactors into their designated sites. Among the transient metals in living cells, iron is the most abundant element that present as an iron sulfur cluster, mono- and dinuclear iron centers or heme for catalytic reactions. Iron homeostasis is tightly regulated by intestinal iron absorption in mammals owing to the lack of an iron excretive transport system, apart from superficial epithelial cell detachment and urinary outflow reabsorptive impairment. In mammals, the central site for iron absorption is in the duodenum, where the divalent metal transporter 1 is essential for iron uptake. The most notable manifestation of mutated divalent metal transporter 1 presents as iron deficiency anemia in humans. In contrast, the mutation of ferroportin, which exports iron, causes iron overload by either gain or loss of function. Furthermore, hepcidin secretion from the liver suppresses iron efflux by internalizing and degrading ferroportin; thus, the hepcidin/ferroportin axis is extensively investigated for its potential as a therapeutic target to treat iron overload. This review focuses on the divalent metal transporter 1-mediated intestinal iron uptake and hepcidin/ferroportin axis that regulate systemic iron homeostasis.

Post-Partum Clinical and Patient-Reported Outcome Changes in Mothers with Multiple Sclerosis: Findings from the NAPPREMS Study.

Background and Objective: Pregnancy in mothers with multiple sclerosis (MS) commonly results in significant changes in disease activity and changes in clinical care, including the discontinuation of disease modifying therapy (DMT). This study aimed at understanding the clinical and patient-reported outcomes (PROs) before, during and 1-year after delivery. Materials and Methods: A total of 30 pregnant mothers with MS were recruited as part of the study. Clinical (relapse activity and disability changes), PRO information and MRI outcomes were collected on four separate visits: one baseline visit-0-30 days post-delivery; and 3 follow-up visits at week 24, week 36 and week 52 from the baseline. PRO was assessed using a validated questionnaire called the Fatigue Scale for Motor and Cognitive Function (FSMC). The MRI scans were analyzed, and the count of new T2 lesions and/or contrast-enhancing lesions was determined. Results: The average time between delivery and the start of DMT was 142.5 days. Relapse activity before the pregnancy was numerically linked with the activity during the pregnancy, where up to 57.1% of the activity during pregnancy occurred in pwMS with previously active disease before conception (statistically trending with p = 0.073). The relapse activity after the pregnancy occurred twice as often in pwMS whose MS was clinically active before conception. All five pwMS who experienced a relapse prior to the pregnancy experienced worsening in their physical PRO domain. Conclusions: Pre-pregnancy activity is crucial in the screening of mothers with MS at risk for post-partum relapses, worsening of clinical disability and/or PRO measures. A post-partum MS period may benefit from the routine PRO utilization and screening for its worsening. The inflammatory activity during pregnancy was not associated with short-term disease progression.

Anti-Inflammatory Effects of Serotonin Receptor and Transient Receptor Potential Channel Ligands in Human Small Intestinal Epithelial Cells.

Intestinal inflammation and dysbiosis can lead to inflammatory bowel diseases (IBD) and systemic inflammation, affecting multiple organs. Developing novel anti-inflammatory therapeutics is crucial for preventing IBD progression. Serotonin receptor type 2A (5-HT2A) ligands, including psilocybin (Psi), 4-Acetoxy-N,N-dimethyltryptamine (4-AcO-DMT), and ketanserin (Ket), along with transient receptor potential (TRP) channel ligands like capsaicin (Cap), curcumin (Cur), and eugenol (Eug), show promise as anti-inflammatory agents. In this study, we investigated the cytotoxic and anti-inflammatory effects of Psi, 4-AcO-DMT, Ket, Cap, Cur, and Eug on human small intestinal epithelial cells (HSEIC). HSEIC were exposed to tumor necrosis factor (TNF)-α and interferon (IFN)-γ for 24 h to induce an inflammatory response, followed by treatment with each compound at varying doses (0-800 µM) for 24 to 96 h. The cytotoxicity was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and protein expression by Western blot (WB) analysis. As single treatments, Psi (40 µM), Cur (0.5 µM), and Eug (50 µM) significantly reduced COX-2 levels without cytotoxic effects. When combined, Psi (40 µM) and Cur (0.5 µM) exhibited synergy, resulting in a substantial decrease in COX-2 protein levels (-28× fold change), although the reduction in IL-6 was less pronounced (-1.6× fold change). Psi (20 µM) and Eug (25 µM) demonstrated the most favorable outcomes, with significant decreases in COX-2 (-19× fold change) and IL-6 (-10× fold change) protein levels. Moreover, the combination of Psi and Eug did not induce cytotoxic effects in vitro at any tested doses. This study is the first to explore the anti-inflammatory potential of psilocybin and 4-AcO-DMT in the intestines while highlighting the potential for synergy between the 5-HT2A and TRP channel ligands, specifically Psi and Eug, in alleviating the TNF-α/IFN-γ-induced inflammatory response in HSEIC. Further investigations should evaluate if the Psi and Eug combination has the therapeutic potential to treat IBD in vivo.

A mechanistic insight for the biosynthesis of N,N-dimethyltryptamine: An ONIOM theoretical approach.

Psychoactive natural products are potent serotonergic agonists capable of modulating brain functions such as memory and cognition. These substances have shown therapeutic potential for treating various mental disorders. The fact that N,N-dimethyltryptamine (DMT) is produced endogenously in several plants and animals, including humans, makes it particularly attractive. As an amino acid-derived alkaloid, the DMT biosynthetic pathway is part of the L-tryptophan biochemical cascade and can be divided into the decarboxylation by an aromatic L-amino acid decarboxylase (AADC) for tryptamine formation and the subsequent double-methylation by the indolethylamine-N-methyltransferase (INMT) through the cofactor S-adenosyl-L-methionine (SAM), a methyl donor. Unlike the decarboxylation mechanism of L-tryptophan, the molecular details of the double methylation of tryptamine have not been elucidated. Therefore, we propose an in silico model using molecular dynamics (MD), non-covalent interaction index (NCI) and density functional theory (DFT) calculations with the ONIOM QM:MM B3LYP/6-31+G(d,p):MM/UFF level of theory. Based on the obtained energetic data, the potential energy surface (PES) indicates an SN2 mechanism profile, with the second methylation energy barrier being the rate-limiting step with δG‡=60kJ∙mol-1 larger than the previous methylation, following the NCI analysis showing more repulsive interactions for the second transition state. In addition, the hybridization information of each reaction step provides geometric details about the double-methylation.

"In vivo biosynthesis of N,N-dimethyltryptamine, 5-MeO-N,N-dimethyltryptamine, and bufotenine in E.coli".

N,N-dimethyltryptamine (DMT), 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) and 5-hydroxy-N,N-dimethyltryptamine (bufotenine) are psychedelic tryptamines found naturally in both plants and animals and have shown clinical potential to help treat mental disorders, such as anxiety and depression. Advances in both metabolic and genetic engineering make it possible to engineer microbes as cell factories to produce DMT and its aforementioned derivatives to meet demand for ongoing clinical study. Here, we present the development of a biosynthetic production pathway for DMT, 5-MeO-DMT, and bufotenine in the model microbe Escherichia coli. Through the application of genetic optimization techniques and process optimization in benchtop fermenters, the in vivo production of DMT in E. coli was observed. DMT production with tryptophan supplementation reached maximum titers of 74.7 ± 10.5 mg/L under fed batch conditions in a 2-L bioreactor. Additionally, we show the first reported case of de novo production of DMT (from glucose) in E. coli at a maximum titer of 14.0 mg/L and report the first example of microbial 5-MeO-DMT and bufotenine production in vivo. This work provides a starting point for further genetic and fermentation optimization studies with the goal to increase methylated tryptamine production metrics to industrially competitive levels.

Multiple Sclerosis Pathogenesis and Updates in Targeted Therapeutic Approaches.

PURPOSE OF REVIEW: In this review, we provide a comprehensive update on current scientific advances and emerging therapeutic approaches in the field of multiple sclerosis. RECENT FINDINGS: Multiple sclerosis (MS) is a common disorder characterized by inflammation and degeneration within the central nervous system (CNS). MS is the leading cause of non-traumatic disability in the young adult population. Through ongoing research, an improved understanding of the disease underlying mechanisms and contributing factors has been achieved. As a result, therapeutic advancements and interventions have been developed specifically targeting the inflammatory components that influence disease outcome. Recently, a new type of immunomodulatory treatment, known as Bruton tyrosine kinase (BTK) inhibitors, has surfaced as a promising tool to combat disease outcomes. Additionally, there is a renewed interested in Epstein-Barr virus (EBV) as a major potentiator of MS. Current research efforts are focused on addressing the gaps in our understanding of the pathogenesis of MS, particularly with respect to non-inflammatory drivers. Significant and compelling evidence suggests that the pathogenesis of MS is complex and requires a comprehensive, multilevel intervention strategy. This review aims to provide an overview of MS pathophysiology and highlights the most recent advances in disease-modifying therapies and other therapeutic interventions.