Transcriptome sequencing reveals novel molecular features of SLE severity

Introduction: Systemic lupus erythematosus (SLE) is an autoimmune disorder characterized by the production of autoantibodies, immune complex deposition, and tissue/organ damage. In this study, we aimed to identify molecular features and signaling pathways associated with SLE severity using RNA sequencing (RNA-seq), single-cell RNA sequencing (scRNA-seq), and clinical parameters. Methods: We analyzed transcriptome profiles of 45 SLE patients, grouped into mild (mSLE, SLEDAI ≤ 9) and severe (sSLE, SLEDAI > 9) based on SLE Disease Activity Index (SLEDAI) scores. We also collected clinical data on anti-dsDNA, ANA, ESR, CRP, snRNP, AHA, and anti-Smith antibody status for each patient. Results: By comparing gene expression across groups, we identified 12 differentially expressed genes (DEGs), including 7 upregulated (CEACAM6, UCHL1, ARFGEF3, AMPH, SERPINB10, TACSTD2, and OTX1) and 5 downregulated (SORBS2, TRIM64B, SORCS3, DRAXIN, and PCDHGA10) DEGs in sSLE compared to mSLE. Furthermore, using the CIBERSORT algorithm, we found that Treg cells were significantly decreased in sSLE and negatively correlated with AMPH expression, which was mainly expressed in Treg cells from SLE patients according to public scRNA-seq data (GSE135779). Discussion: Overall, our findings shed light on the molecular mechanisms underlying SLE severity and provide insight into potential therapeutic targets.

Effects of amphetamine and methylphenidate on attentional performance and impulsivity in the mouse 5-Choice Serial Reaction Time Task

BACKGROUND

Few studies have investigated the effects of conventional attention deficit-hyperactivity disorder (ADHD) medication in the mouse 5-choice serial reaction time task (5-CSRTT), and rat studies have yielded inconsistent results.

OBJECTIVE

We aimed to examine the effects of acute methylphenidate (MPH) and amphetamine (AMPH) treatment in the mouse 5-CSRTT.

METHODS

Trained male C57Bl/6J mice were tested in a variable stimulus duration schedule. Effects of AMPH (0.25, 0.5, and 1 mg/kg) and MPH (0.5, 1.0, and 2.0 mg/kg) on discriminative accuracy, omissions, and premature responses were assessed. Saline treatment data determined high- and low-attentive (LA), and high- and low-impulsive (LI) subgroups according to the upper and lower 30th percentiles, respectively.

RESULTS

In the LA subgroup accuracy was improved by 0.5 mg/kg AMPH and 2 mg/kg MPH, while no effect was found in the high-attentive (HA) subgroup. Premature responses were increased by 1 mg/kg AMPH and 0.5 mg/kg MPH for all animals, and by 1 mg/kg AMPH for the LI subgroup.

CONCLUSIONS

The use of variable stimulus duration, along with the division into high- and LA, and high-and LI subgroups, may improve the sensitivity of the 5-CSRTT when investigating drug effects on attention and impulsivity.

N-terminus regulation of VMAT2 mediates methamphetamine-stimulated efflux

The 20 amino acid (AA) N-terminus of the vesicular monoamine transporter 2 (VMAT2) was examined as a regulator of VMAT2 function. Removal of the first 16 or 19 AAs of the N-terminus resulted in a molecule with reduced ability to sequester [(3)H]-5HT. A glutathione-S-transferase-construct of the N-terminus underwent phosphorylation in the presence of PKC at serines 15 and 18. These putative phosphorylation sites were examined for effects on function. Phospho-mimetic substitution of serines 15 and 18 with aspartate in the full-length VMAT2 resulted in reduced [(3)H]-5HT sequestration and reduced methamphetamine (METH)-stimulated efflux of preloaded [(3)H]-5HT. In contrast, mutation of serines 15 and 18 to alanines maintained intact net substrate sequestration but eliminated METH-stimulated efflux of pre-accumulated [(3)H]-5HT. In summary, these data suggest a model in which the VMAT2 N-terminus regulates monoamine sequestration.

Influence of lifelong dietary fats on the brain fatty acids and amphetamine-induced behavioral responses in adult rat

The influence of dietary fatty acids (FA) on mania-like behavior and brain oxidative damage were evaluated in rats. First generation of rats born and maintained under supplementation with soybean-oil (SO), fish-oil (FO) or hydrogenated-vegetable-fat (HVF), which are rich in n-6, n-3 and trans (TFA) FA, respectively, until adulthood, were exposed to an amphetamine (AMPH)-induced mania animal model to behavioral and biochemical evaluations. While AMPH caused hyperlocomotion in HVF and, to a less extent, in SO- and FO-groups, a better memory performance was observed in FO group. Among vehicle-groups, HVF increased reactive species (RS) generation and protein-carbonyl (PC) levels in cortex; FO reduced RS generation in hippocampus and decreased PC levels in hippocampus and striatum. Among AMPH-treated animals, HVF exacerbated RS generation in all evaluated brain areas and increased PC levels in cortex and striatum; FO reduced RS generation in hippocampus and decreased PC levels in hippocampus and striatum. FO was related to higher percentage of polyunsaturated fatty acids (PUFA) and docosahexaenoic acid (DHA) in cortex and striatum, while HVF was associated to higher incorporation of TFA in cortex, hippocampus and striatum, besides increased n-6/n-3 FA ratio in striatum. While a continuous exposure to TFA may intensify oxidative events in brain, a prolonged FO consumption may prevent mania-like-behavior; enhance memory besides decreasing brain oxidative markers. A substantial inclusion of processed foods, instead of foods rich in omega-3, in the long term is able to influence the functionality of brain structures related to behavioral disturbances and weaker neuroprotection, whose impact should be considered by food safety authorities and psychiatry experts.

Effects of withdrawal from repeated amphetamine exposure in peri-puberty on neuroplasticity-related genes in mice

Although extensive evidence demonstrates that repeated administration of amphetamine (AMPH) induces behavioral and neurochemical sensitization, the influence of the developmental timing of AMPH administration is unknown. This is an important issue to address because it could help clarify the influence of early drug exposure on neuronal plasticity and the involvement of dopaminergic sensitization in the etiopathology of neuropsychiatric disorders. Thus, we decided to investigate the molecular alterations induced by the administration of AMPH during adolescence, when repeated exposure to the psychostimulant may interfere with developmental neuroplasticity. We investigated the expression of the neurotrophin brain-derived neurotrophic factor (BDNF) and of two inducible-early genes (arc and cfos) that bridge neuronal activity with long-lasting functional alterations. We found that peri-pubertal treatment with AMPH induces long-lasting changes in the expression of bdnf and of activity-regulated genes in the hippocampus and in the prefrontal/frontal cortex, and leads to alterations of their short-term modulation in response to a subsequent acute AMPH challenge. These data suggest that AMPH exposure in peri-puberty may negatively affect the maturation of brain structures, such as the prefrontal cortex, which facilitate the development of dopamine sensitization and may contribute to dopamine-dependent behavioral dysfunctions and molecular alterations in adulthood.