Biology subjects

Magalhaes, J.

Publications and source records attributed to Magalhaes, J..

6 recordsLinked to original sources

bioRxiv2026

Antidepressant Effects of Lauric Acid in a Corticosterone-Induced Murine Model of Depression: Behavioral and Neurochemical Insights

BackgroundLauric acid (LA) is a medium-chain saturated fatty acid found in several foods, including vegetable oils and seeds. Previous studies have demonstrated that LA exhibits neuroprotective, antioxidant, and anti-inflammatory properties in experimental models of neuropsychiatric disorders. Therefore, the present study aimed to investigate the behavioral and neurochemical effects of LA in a corticosterone-induced murine model of depression. MethodsMale Swiss mice received corticosterone (CORT; 20 mg/kg, subcutaneously) for 23 consecutive days, while the control group received vehicle only. During the last nine days of the experimental protocol, the animals received the respective treatments by oral gavage: LA (10 or 20 mg/kg), fluvoxamine (FLUV; 50 mg/kg), or vehicle, administered 1 hour after CORT injection. One hour after treatment administration, the animals were subjected to the behavioral tests: Forced Swimming Test (FST), Tail Suspension Test (TST), and Open Field Test (OFT). At the end of the experimental protocol, the animals were euthanized, and the prefrontal cortex (PFC), hippocampus (HPC), and striatum (STR) were collected for neurochemical analyses. ResultsChronic CORT treatment significantly increased immobility time in the FST and TST, characterizing depressive-like behavior. Treatment with LA reversed these behavioral alterations, showing an effect similar to that observed in the FLUV-treated group. In the OFT, LA did not promote significant changes in locomotor activity, suggesting the absence of psychostimulant effects. Regarding neurochemical analyses, LA treatment did not reduce malondialdehyde (MDA) or nitrite/nitrate (NO2-/NO3-) levels, nor did it alter reduced glutathione (GSH) levels in the evaluated brain regions. ConclusionThe results demonstrated that LA treatment was able to reverse corticosterone-induced behavioral alterations in mice, indicating a potential antidepressant-like effect. Furthermore, the observed effects were not associated with nonspecific locomotor alterations. Although LA did not promote significant changes in the evaluated neurochemical markers, these findings reinforce its potential as a therapeutic agent for depressive disorders and highlight the need for further studies to elucidate its mechanisms of action and possible clinical applicability.

neuroscience↗

bioRxiv2024

Rac1 inhibition prevents axonal cytoskeleton dysfunction in Transthyretin Amyloid Polyneuropathy

Hereditary transthyretin amyloidosis with polyneuropathy (ATTRv-PN) is characterized by the deposition of amyloidogenic TTR, particularly in dorsal root ganglia (DRG) and peripheral nerve axons, resulting in sensorimotor axonopathy with autonomic dysfunction. Here, we investigated cytoskeleton alterations in peripheral axons from an ATTRv-PN mouse model, the hTTRA97S knock-in mice. Proteomics of hTTRA97S sural nerves revealed dysregulation of actin-related proteins. hTTRA97S DRG neurons presented a defective actin distribution in growth cones along with a reduction in axonal actin trails, and an associated impairment in the pool of pre-synaptic vesicles. Microtubule dynamics and axonal transport abnormalities were also observed in mutant axons. Importantly, cytoskeletal defects in hTTRA97S neurons preceded axonal degeneration and were mediated by Rac1 hyperactivation in DRG neurites and sciatic nerves of pre-symptomatic mice. Rac1 inhibition rescued cytoskeleton alterations, preventing degeneration. Remarkably, in ATTRv-PN patients with late-onset disease, a variant in RACGAP1, encoding a Rac1 inactivator, supported the neuroprotective role of Rac1 inhibition. Our findings demonstrate that cytoskeletal defects precede axonal degeneration in ATTRv-PN and highlight Rac1 as a promising therapeutic target.

neuroscience↗

bioRxiv2021

Sorghum Root Epigenetic Landscape During Limiting Phosphorus Conditions

Efficient acquisition and use of available phosphorus from the soil is crucial for plant growth, development, and yield. With an ever-increasing acreage of croplands with suboptimal available soil phosphorus, genetic improvement of sorghum germplasm for enhanced phosphorus acquisition from soil is crucial to increasing agricultural output and reducing inputs, while confronted with a growing world population and uncertain climate. Sorghum bicolor is a globally important commodity for food, fodder, and forage. Known for robust tolerance to heat, drought, and other abiotic stresses, its capacity for optimal phosphorus use efficiency (PUE) is still being investigated for optimized root system architectures (RSA). Whilst a few RSA-influencing genes have been identified in sorghum and other grasses, the epigenetic impact on expression and tissue-specific activation of candidate PUE genes remains elusive. Here, we present transcriptomic, epigenetic, and regulatory network profiling of RSA modulation in the BTx623 sorghum background in response to limiting phosphorus (LP) conditions. We show that during LP, sorghum RSA is remodeled to increase root length and surface area, likely enhancing its ability to acquire P. Global DNA 5-methylcytosine and H3K4 and H3K27 trimethylation levels decrease in response to LP, while H3K4me3 peaks and DNA hypomethylated regions contain recognition motifs of numerous developmental and nutrient responsive transcription factors that display disparate expression patterns between different root tissues (primary root apex, elongation zone, and lateral root apex). Suggesting that epigenetic shifts during growth on LP results in targeted gene expression in a tissue-specific manner that optimizes the RSA for improved P uptake. SummaryIn response to low P, epigenetic and transcriptional changes stimulate lateral root growth in Sorghum bicolor BTx623, increasing the root surface area for enhanced "mining" of P from the soil.

plant biology↗

bioRxiv2021

Substrate ligand density modulates gap junction intercellular communication during mesenchymal cell condensation

To unveil the influence of cell-matrix adhesions in the establishment of gap junction intercellular communication (GJIC) during cell condensation in chondrogenesis. Materials & MethodsPreviously developed nanopatterns of the cell adhesive ligand arginine-glycine-aspartic acid (RGD) were used as cell culture substrates to control cell adhesion at the nanoscale. We conducted in vitro chondrogenesis of mesenchymal stem cells on the nanopatterns. We evaluated cohesion and GJIC in cell condensates. ResultsMechanical stability and GJIC are enhanced by a nanopattern configuration in which 90% of the surface area presents adhesion sites separated less than 70 nm, thus providing an onset for cell signaling. ConclusionCell-matrix adhesions regulate GJIC of mesenchymal cell condensates during in vitro chondrogenesis from a threshold configuration at the nanoscale.

bioengineering↗

bioRxiv2021

Transthyretin promotes axon growth via regulation of microtubule dynamics and tubulin acetylation

Transthyretin (TTR), a plasma and cerebrospinal fluid protein, increases axon growth and organelle transport in sensory neurons. These TTR functions were suggested to underlie its activity in promoting nerve regeneration. While neurons extend their axons, the microtubule (MT) cytoskeleton is crucial for the segregation of functional compartments and axonal outgrowth. Herein, we investigated the hypothesis that TTR promotes axon elongation and regeneration by modulating MT dynamics. Indeed, we found that TTR KO mice have an intrinsic increase in dynamic MTs and reduced levels of acetylated -tubulin in uninjured peripheral axons, and fail to modulate microtubule dynamics in response to sciatic nerve injury. Importantly, restoring acetylated -tubulin levels of TTR KO DRG neurons using an HDAC6 inhibitor was sufficient to completely revert defective MT dynamics and neurite outgrowth. In summary, our results revealed a new role for TTR in the modulation of MT dynamics by regulating -tubulin acetylation and support that this activity underlies TTR neuritogenic function.

neuroscience↗

bioRxiv2020

Unisexual flower initiation in the monoecious Quercus suber L., a molecular approach

Several plant species display a temporal separation of the male and female flower organ development to enhance outbreeding, however, little is known regarding the genetic mechanisms controlling this temporal separation. Quercus suber is a monoecious oak tree with accentuated protandry: in late winter, unisexual male flowers emerge adjacent to the swollen buds, whereas unisexual female flowers emerge in the axils of newly formed leaves formed during spring (4 to 8 weeks after male flowering). Here, phylogenetic profiling lead to the identification of cork oak homologs of key floral regulatory genes. The role of these cork oak homologs during flower development was identified with functional studies in Arabidopsis thaliana. The expression profile of flower regulators (inducers and repressors) throughout the year, in leaves and buds, suggests that the development of male and female flowers may be preceded by separated induction events. Female flowers are most likely induced during the vegetative flush occurring in spring, whereas male flowers may be induced in early summer, staying enclosed within the pre-dormant buds, but complete their development before the vegetative flush of the following year, displaying a long period of anthesis that spans the dormant period. Results portray a genetic mechanism that may explain similar reproductive habits in other tree species.

plant biology↗