Biology subjects

Lalonde, J.

Publications and source records attributed to Lalonde, J..

5 recordsLinked to original sources

bioRxiv2025

Preclinical Study of Cannflavins A and B Action Against Glioblastoma Cells

AO_SCPLOWBSTRACTC_SCPLOWO_ST_ABSBackgroundC_ST_ABSFlavonoids represent a large group of naturally occurring polyphenolic compounds, many of which have been found to produce valuable biological outcomes, including action against cancer cells. Glioblastoma multiforme (GBM) is an aggressive type of brain tumor that is associated with a poor prognosis and has limited treatment options. Previous findings suggest that cannflavins can produce promising effects for pancreatic and bladder cancers, but the efficacy of these phytochemicals in attacking brain tumour cells remains unknown. Our study evaluates the potential of cannflavin A and cannflavin B against GBM cells using a range of in vitro approaches. ResultsWe conducted experiments using A-172 and U-87 GBM lines to assess the impact of cannflavins A and B on cell viability, cycle, migration, and invasion capacity. Our results revealed a consistent dose-dependent decrease in cell viability in both lines after the addition of cannflavin B to the culture media. Interestingly, we found that chrysoeriol (the non-prenylated synthesis precursor of cannflavins in the Cannabis sativa plant) only has a limited adverse effect on survival using the same approach, while techtochrysin (an O-methylated flavone) has none. Using time-lapse live-cell imaging and a scratch assay, we also show that cannflavins can inhibit tumor cell migration at concentrations below those that produce significant cell death. Finally, we found that cannflavin B exhibits anti-migratory and anti-invasive properties in transwell and tumorsphere assays, underscoring its multifaceted therapeutic potential. ConclusionThese findings suggest that cannflavin B holds promise as a therapeutic agent in the treatment of GBM. HO_SCPLOWIGHLIGHTSC_SCPLOWO_LICannflavin B but not cannflavin A limits the viability of A-172 and U-87 GBM cells in a concentration- and time-dependent manner. C_LIO_LIUsing time-lapse live-cell imaging and a scratch assay, we provide evidence that cannflavins A and B can inhibit GBM cell migration at concentrations below those that result in a significant reduction in cell viability. C_LIO_LICannflavin B exhibits robust anti-migratory and anti-invasive properties in transwell and tumorsphere assays, underscoring its multifaceted therapeutic potential. C_LIO_LIAlthough previous work had reported the capacity of cannflavins A and B to interfere with TrkB and downstream the MAPK/AKT signaling pathways in mouse primary neurons, the effect of those molecules is limited in GBMs, suggesting that other targets are engaged to produce the cellular effects. C_LI

pharmacology and toxicology↗

bioRxiv2024

Prenatal exposure to valproic acid induces sex-specific alterations in cortical and hippocampal neuronal structure and function in rats

BackgroundThere are substantial differences in the characteristics of males and females with an autism spectrum disorder (ASD), yet there is little knowledge surrounding the mechanistic underpinnings of these differences. The valproic acid (VPA) rodent model is the most widely used model for the study of idiopathic ASD, but almost all of the studies have used male rodents. MethodTo fill this knowledge gap, we evaluated sex differences for neuronal activity, morphology, and glycogen synthase kinase-3 (GSK-3) signaling in primary cortical (CTX) and hippocampal (HIP) neurons prepared from rats exposed to VPA in utero. In vivo, sex-specific VPA-induced alterations in the frontal CTX transcriptome at birth were also determined. ResultsOverall, VPA induced more robust changes in neuronal function and structure in the CTX than in the HIP. Male- and female-derived primary CTX neurons from rats exposed to prenatal VPA had elevated activity and showed more disorganized firing. In the HIP, only the female VPA neurons showed elevated firing, while the male VPA neurons exhibited disorganized activity. Dendritic arborization of CTX neurons from VPA rats was less complex in both sexes, though this was more pronounced in the females. Conversely, both female and male HIP neurons from VPA rats showed elevated complexity distal to the soma. Female VPA CTX neurons also had an elevated number of dendritic spines. The relative activity of the and {beta} isoforms of GSK-3 were suppressed in both female and male VPA CTX neurons, with no changes in the HIP neurons. On postnatal day 0, alterations in CTX genes associated with neuropeptides (e.g., penk, pdyn) and receptors (e.g., drd1, adora2a) were seen in both sexes, though they were downregulated in females and upregulated in males. LimitationsPrimary neuron studies may not recapitulate findings performed in vivo or at later stages of development. ConclusionTogether these findings suggest that substantial sex differences in neuronal structure and function in the VPA model may have relevance to the reported sex differences in idiopathic ASD.

neuroscience↗

bioRxiv2022

Interference of Neuronal TrkB Signaling by the Cannabis-Derived Flavonoids Cannflavins A and B

Cannflavins A and B are flavonoids that accumulate in the Cannabis sativa plant. These specialized metabolites are uniquely prenylated and highly lipophilic, which, a priori, may permit their interaction with membrane-bound enzymes and receptors. Although previous studies found that cannflavins can produce anti-inflammatory responses by inhibiting the biosynthesis of pro- inflammatory mediators, the full extent of their cellular influence remains to be understood. Here, we studied these flavonoids in relation to the Tropomyosin receptor kinase B (TrkB), a receptor tyrosine kinase that is activated by the growth factor brain-derived neurotrophic factor (BDNF). Using mouse primary cortical neurons, we first collected evidence that cannflavins prevent the accumulation of Activity-regulated cytoskeleton-associated (Arc, also known as Arg3.1) protein upon TrkB stimulation by exogenous BDNF in these cells. Consistent with this effect, we also observed a reduced activation of TrkB and downstream signaling effectors that mediate Arc mRNA transcription when BDNF was co-applied with the cannflavins. Of note, we also performed a high-throughput screen that demonstrated a lack of agonist action of cannflavins towards 320 different G protein-coupled receptors, a result that specifically limit the possibility of a TrkB transinactivation scenario via G protein signaling to explain our results with dissociated neurons. Finally, we used Neuro2a cells overexpressing TrkB to show that cannflavins can block the growth of neurites and increased survival rate produced by the higher abundance of the receptor in this model. Taken together, our study offers a new path to understand the reported effects of cannflavins and other closely related compounds in different cellular contexts.

pharmacology and toxicology↗

bioRxiv2022

Human Cerebral Spheroids Undergo Activity Dependent Changes In Cellular Composition And MicroRNA Expression

Activity-induced neurogenesis has been extensively studied in rodents but the lack of ante mortem accessibility to human brain at the cellular and molecular levels limits studies of the process in humans. Using cerebral spheroids derived from human induced pluripotent stem cells (iPSCs), we investigated the effects of increased neuronal activity on neurogenesis. Our studies demonstrate that increasing neuronal activity with 4-aminopyridine in 3-month-old cerebral spheroids is associated with increases in the numbers of new neurons and decreases in the population of new glial cells. We also observed a significant decrease in the expression of miR-135a, which has previously been shown to be decreased in exercise-induced neurogenesis. Predicted targets of miR-135a include key participants in the SMAD2/3 and BDNF pathways. Together, our results suggest that iPSC-derived cerebral spheroids are an attractive model to study some aspects of activity-induced neurogenesis.

neuroscience↗

bioRxiv2021

Phosphorylation-dependent control of Arc protein by synaptic plasticity regulator TNIK

Activity-regulated cytoskeleton-associated protein (Arc) is an immediate-early gene product that support neuroplastic changes important for cognitive function and memory formation. As a protein with homology to the retroviral Gag protein, a particular characteristic of Arc is its capacity to self-assemble into virus-like capsids that can package mRNAs and transfer those transcripts to other cells. Although a lot has been uncovered about the contributions of Arc to neuron biology and behavior, very little is known about how different functions of Arc are coordinately regulated both temporally and spatially in neurons. The answer to this question we hypothesized must involve the occurrence of different protein post-translational modifications acting to confer specificity. In this study, we used mass spectrometry and sequence prediction strategies to map novel Arc phosphorylation sites. Our approach led us to recognize serine 67 (S67) and threonine 278 (T278) as residues that can be modified by TNIK, which is a kinase abundantly expressed in neurons that shares many functional overlaps with Arc and has, along with its interacting proteins such as the NMDA receptor, been implicated as a risk factor for psychiatric disorders. Furthermore, characterization of each residue using site-directed mutagenesis to create S67 and T278 mutant variants revealed that TNIK action at those amino acids can strongly influence Arcs subcellular distribution and self-assembly as capsids. Together, our findings reveal an unsuspected connection between Arc and TNIK. Better understanding of the interplay between these two proteins in neuronal cells could lead to new insights about apparition and progression of psychiatric disorders.

neuroscience↗