The role of selenoproteins in neurodevelopment and neurological function: Implications in autism spectrum disorder

Selenoprotein T, a potential treatment of attention-deficit/hyperactivity disorder and comorbid pain in neonatal 6-OHDA lesioned mice

pathological pain and Attention-deficit/hyperactivity disorder (ADHD) are two complex multifactorial syndromes. The comorbidity of ADHD and altered pain perception is well documented in children, adolescents, and adults. According to pathophysiological investigations, the dopaminergic system's dysfunction provides a common basis for ADHD and comorbid pain. Growing evidence suggests that oxidative stress may be crucial in both pathologies. Recent studies revealed that a small peptide encompassing the redox-active site of selenoprotein T (PSELT), protects dopaminergic neurons and fibers as well as lesioned nerves in animal models. The current study aims to examine the effects of PSELT treatment on ADHD-like symptoms and pain sensitivity, as well as the role of catecholaminergic systems in these effects. Our results demonstrated that intranasal administration of PSELT reduced the hyperactivity in the open field, decreased the impulsivity displayed by 6-OHDA-lesioned male mice in the 5-choice serial reaction time task test and improved attentional performance. In addition, PSELT treatment significantly increased the nociception threshold in both normal and inflammatory conditions. Furthermore, anti-hyperalgesic activity was antagonized with sulpiride pre-treatment, but not by phentolamine, or propranolol pre-treatments. The present study suggests that PSELT reduces the severity of ADHD symptoms in mice and possesses potent antinociceptive effects which could be related to the involvement of D2/D3 dopaminergic receptors.

The effect of selenium supplementation on oxidative stress, clinical symptoms and mental health status in patients with migraine: a study protocol for a double-blinded randomized clinical trial

BACKGROUND

Despite a number of recommended strategies, effective treatment of migraine remains elusive. Given the role of oxidative stress in the pathogenesis of migraine, selenium, as an antioxidant nutrient, may have a beneficial effect on migraine outcomes. However, no study has explored the effects of selenium supplementation on migraine symptoms, oxidative stress biomarkers, and mental health. Therefore, this randomized, double-blinded, placebo-controlled clinical trial aims to examine the effects of selenium supplementation among migraine patients.

METHODS

Seventy-two migraine patients will receive either 200 µg/day selenium supplement (n = 36) or placebo (n = 36) for 12 weeks in a randomized, double-blinded, placebo-controlled study. The severity, frequency, and duration of headaches, mental health indices including depression, anxiety, and distress, and quality of life, as well as biomarkers of oxidative stress such as nitric oxide (NO), malondialdehyde (MDA), total antioxidant capacity (TAC), and total oxidant status (TOS), will be measured at the baseline and end of the study. The intention-to-treat (ITT) approach will be used to estimate missing values. One-way analysis of covariance (ANCOVA) will be performed to detect the effect of selenium supplementation on outcome variables.

DISCUSSION

Oxidative stress is recognized as a key contributor to migraine pathogenesis. Selenium is an essential trace element with antioxidant properties, capable of crossing the blood-brain barrier (BBB), holding promise to alleviate the oxidative stress and neurotoxicity. Thus, selenium may beneficially affect clinical symptoms and oxidative stress as well as the quality of life in migraine patients.

TRIAL REGISTRATION

This trial was registered in the Iranian Registry of Clinical Trials ( https://www.irct.ir/ ) on 27 May 2023 with the code number IRCT20121216011763N60.

tRNA modification enzyme-dependent redox homeostasis regulates synapse formation and memory

Post-transcriptional modification of RNA regulates gene expression at multiple levels. ALKBH8 is a tRNA modifying enzyme that methylates wobble uridines in specific tRNAs to modulate translation. Through methylation of tRNA-selenocysteine, ALKBH8 promotes selenoprotein synthesis and regulates redox homeostasis. Pathogenic variants in ALKBH8 have been linked to intellectual disability disorders in the human population, but the role of ALKBH8 in the nervous system is unknown. Through in vivo studies in Drosophila, we show that ALKBH8 controls oxidative stress in the brain to restrain synaptic growth and support learning and memory. ALKBH8 null animals lack wobble uridine methylation and exhibit a global reduction in protein synthesis, including a specific decrease in selenoprotein levels. Loss of ALKBH8 or independent disruption of selenoprotein synthesis results in ectopic synapse formation. Genetic expression of antioxidant enzymes fully suppresses synaptic overgrowth in ALKBH8 null animals, confirming oxidative stress as the underlying cause of dysregulation. ALKBH8 animals also exhibit associative learning and memory impairments that are reversed by pharmacological antioxidant treatment. Together, these findings demonstrate the critical role of tRNA modification in redox homeostasis in the nervous system and reveal antioxidants as a potential therapy for ALKBH8-associated intellectual disability.

Micronutrient Research in Autism Spectrum Disorder. A Clinical Study

Autistic spectrum disorders are part of the category of neurodevelopmental disorders, characterized by: difficulties in communication and social interaction, restrictive and repetitive patterns of behaviours and activities, which are present throughout the developmental period, and can be diagnosed in the first five years of life. Due to the increase in the incidence of this disorder in recent years, it has become a topic of great interest both to specialists in child and adolescent psychiatry and to researchers in the field. Given the polymorphism of Autism Spectrum Disorder and the need to discover factors that better explain the etiology of this disorder, studies related to biomarkers are extremely varied. One of the areas of study that have exercised particular interest is related to the involvement of metals in the pathology of autism spectrum disorder. Apart from the controversies related to heavy metals that according to studies affect the developmental process, there are studies that suggest that some micronutrients such as zinc, copper, selenium, iron, magnesium, may be involved in the etiology of autism spectrum disorder. Starting from these studies, we set out to investigate to what extent these essential metals for the body are involved in the etiology of autism spectrum disorder and how they influence the severity of symptoms.