Biology subjects

Reis, S. A.

Publications and source records attributed to Reis, S. A..

3 recordsLinked to original sources

bioRxiv2026

Mapping Endogenous Psychedelic Chemistry: Indolethylamine N-Methyltransferase (INMT) Localizes Proximal to the Golgi Apparatus of Human Neurons

N,N-dimethyltryptamine (DMT) is a serotonergic psychedelic with a history of ethnobotanical use and emerging clinical efficacy for neuropsychiatric disorders. Following Julius Axelrod's pioneering studies showing DMT production in human tissues, DMT has been proposed as an endogenous neuromodulator because it is a serotonin 2A receptor (5-HT2A R) agonist. However, the DMT-producing enzyme, indolethylamine N-methyltransferase (INMT), has not been characterized at the protein level in the human central nervous system. Here, we validated an anti-INMT antibody and used immunocytochemistry to show that INMT localizes in close proximity to other DMT biosynthetic enzymes near the cytosolic face of the cis-Golgi network in human induced pluripotent stem cell-derived neurons, with immunoreactivity observed across multiple neuronal Golgi phenotypes. Notably, both DMT-like and 5-HT2A R immunoreactivity also partially localized in close proximity to the Golgi apparatus. Our results establish the first protein-level characterization of INMT in human neurons and identify the cis-Golgi network as a candidate microdomain for psychedelic tryptamine biosynthesis. We propose that INMT catalytic activity at the cis-Golgi network creates an enriched region of membrane-permeable psychedelic tryptamines that can access an intracellular 5- HT2A R pool. These findings provide new tools and insights that can inform efforts to understand the mechanism of action of psychedelics under clinical investigation and to target endogenous tryptamines therapeutically.

neuroscience↗

bioRxiv2018

Disruption of The Psychiatric Risk Gene Ankyrin 3 Enhances Microtubule Dynamics Through GSK3/CRMP2 Signaling

The ankyrin 3 gene (ANK3) is a well-established risk gene for psychiatric illness, but the mechanisms underlying its pathophysiology remain elusive. We examined the molecular effects of disrupting brain-specific Ank3 isoforms in mouse and neuronal model systems. RNA sequencing of hippocampus from Ank3+/- and Ank3+/+ mice identified altered expression of 282 genes that were enriched for microtubule-related functions. Results were supported by increased expression of microtubule end-binding protein 3 (EB3), an indicator of microtubule dynamics, in Ank3+/- mouse hippocampus. Live-cell imaging of EB3 movement in primary neurons from Ank3+/- mice revealed impaired elongation of microtubules. Using a CRISPR-dCas9-KRAB transcriptional repressor in mouse neuro-2a cells, we determined that repression of brain-specific Ank3 increased EB3 expression, decreased tubulin acetylation, and increased the soluble:polymerized tubulin ratio, indicating enhanced microtubule dynamics. These changes were rescued by inhibition of glycogen synthase kinase 3 (GSK3) with lithium or CHIR99021, a highly selective GSK3 inhibitor. Brain-specific Ank3 repression in neuro-2a cells increased GSK3 activity (reduced inhibitory phosphorylation) and elevated collapsin response mediator protein 2 (CRMP2) phosphorylation, a known GSK3 substrate and microtubule-binding protein. Pharmacological inhibition of CRMP2 activity attenuated the rescue of EB3 expression and tubulin polymerization in Ank3 repressed cells by lithium or CHIR99021, suggesting microtubule instability induced by Ank3 repression is dependent on CRMP2 activity. Taken together, our data indicate that aNK3 functions in neuronal microtubule dynamics through GSK3 and its downstream substrate CRMP2. These findings reveal cellular and molecular mechanisms underlying brain-specific ANK3 disruption that may be related to its role in psychiatric illness.

neuroscience↗

bioRxiv2017

The toxic nature of murine amylin and the immune responsivity of pancreatic islet to conformational antibody in mice

The human amylin is a pancreatic peptide hormone cosecreted with amylin and found in hyperhormonemic state along with insulin in subclinical diabetes. Amylin has been associated with the pathology of type 2 diabetes, particularly due to its ability to assembly into toxic oligomers and amyloid speciments. On the other hand, some variants such as murine amylin has been described as non amyloidogenic, either in vitro or in vivo. Recent data have demonstrated the amyloid propensity of murine amylin and the therapeutic analogue pramlintide, suggesting a universality for amylin amyloidosis. Here we report the amyloidogenesis of murine amylin, which showed lower responsivity to the fluorescent probe thioflavin T compared to human amylin, but presented highly organized fibrilar amyloid material. The aggregation of murine amylin also resulted in the formation of cytotoxic specimens, as evaluated in vitro in INS-1 cells. The aggregation product from murine amylin was responsive to a specific antibody raised against amyloid oligomers, the A11 oligomer antibody. Pancreatic islets of swiss mice have also shown responsivity for the anti-oligomer, indicating the natural abundance of such specimen in rodents. These data provide for the first time evidences for the toxic nature of oligomeric assemblies of murine amylin and its existence in non-transgenic mice.\n\nHighlights- Murine amylin forms oligomer species and amyloid fibrils in vitro\n- The murine amylin aggregation product display cellular toxicity\n- A11 anti-oligomer antibody recognizes murine amylin in vitro\n- Non-transgenic mice display immunoresposivity to anti-oligomer in pancreatic islet

biochemistry↗