Assessment of metal concentrations in the SOD1G93A mouse model of amyotrophic lateral sclerosis and its potential role in muscular denervation, with particular focus on muscle tissue

Sp4/HD11 and Sp1/HAT-p300 complexes induce apoptotic cell death in CuCl2-treated neurons by modulating histone acetylation on BCL-W and BAX promoters

Copper is a metal physiologically present in the brain that becomes neurotoxic at high concentrations; on the other hand, pharmacological inhibition of Histone Deacetylases (HDs) or of Histone Acetyltransferases (HATs) reduce neuronal death caused by several neurotoxicants. Herein, we found that CuCl2 (300 μM in SH-SY5Y cells or 100 μM in cortical neurons) determined apoptotic cell death, that was counteracted by the class IV HDs inhibitor Mocetinostat (MOCE) and by the HAT-p300 inhibitor C646, but not by the class I and II HDs inhibitors. Interestingly, HD11 and HAT-p300 protein levels increased after both 12 and 24 h of CuCl2 exposure and their silencing partially limited CuCl2-neurodetrimental effect. Furthermore, in CuCl2-treated cells the transcriptional factor Sp4 co-localized with HD11 on the promoter of anti-apoptotic gene BCL-W, determining histone H3 hypo-acetylation, a marker of gene repression. Contrarily, Sp1 co-localized with HAT-p300 on the pro-apoptotic gene BAX, determining histone H4 hyper-acetylation, a hallmark of transcriptional activation. In addition, siRNA against Sp4 prevented HD11 binding on BCL-W promoter and its consequent down-regulation, whereas Sp1 knocking-down, by reducing HAT-p300 interaction on BAX gene promoter counteracted its up-regulation. Importantly, while the single knocking-down of Sp1, Sp4, HD11 and HAT-p300 partially mitigated CuCl2-induced cell death, the double-transfection of siRNAs for Sp1 and Sp4, or for HD11 and HAT-p300, completely reverted the neurotoxic effect of CuCl2. Collectively, we found that CuCl2-induced neuronal apoptosis is determined by the binding of Sp1/HAT-p300 and of Sp4/HD11 transcriptional complexes on the BAX and BCL-W gene, respectively, unraveling a new pathway involved in Copper-induced neurotoxicity.

Amyotrophic Lateral Sclerosis and swim training affect copper metabolism in skeletal muscle in a mouse model of disease

INTRODUCTION/AIMS

Swim training and regulation of copper metabolism result in clinical benefits in amyotrophic lateral sclerosis (ALS) mice. Therefore, the study aimed to determine whether swim training improves copper metabolism by modifying copper metabolism in the skeletal muscles of ALS mice.

METHODS

SOD1G93A mice (n = 6 per group) were used as the ALS model, and wild-type B6SJL (WT) mice as controls (n = 6). Mice with ALS were analyzed before the onset of ALS (ALS BEFORE), at baseline ALS (first disease symptoms, trained and untrained, ALS ONSET), and at the end of ALS (last stage disease, trained and untrained, ALS TERMINAL). Copper concentrations and the level of copper metabolism proteins in the skeletal muscles of the lower leg were determined.

RESULTS

ALS disease caused a reduction in the copper concentration in ALS TERMINAL untrained mice compared with the ALS BEFORE (10.43 ± 1.81 and 38.67 ± 11.50 μg/mg, respectively, p = .0213). The copper chaperon for SOD1 protein, which supplies copper to SOD1, and ATPase7a protein (copper exporter), increased at the terminal stage of disease by 57% (p = .0021) and 34% (p = .0372), while the CTR1 protein (copper importer) decreased by 45% (p = .002). Swim training moderately affected the copper concentration and the concentrations of proteins responsible for copper metabolism in skeletal muscles.

DISCUSSION

The results show disturbances in skeletal muscle copper metabolism associated with ALS progression, which is moderately affected by swim training. From a clinical point of view, exercise in water for ALS patients should be an essential element of rehabilitation for maintaining quality of life.

Amyotrophic lateral sclerosis associated disturbance of iron metabolism is blunted by swim training-role of AKT signaling pathway

Swim training has increased the life span of the transgenic animal model of amyotrophic lateral sclerosis (ALS). Conversely, the progress of the disease is associated with the impairment of iron metabolism and insulin signaling. We used transgenic hmSOD1 G93A (ALS model) and non-transgenic mice in the present study. The study was performed on the muscles taken from trained (ONSET and TERMINAL) and untrained animals at three stages of the disease: BEFORE, ONSET, and TERMINAL. In order to study the molecular mechanism of changes in iron metabolism, we used SH-SY5Y and C2C12 cell lines expression vector pcDNA3.1 and transiently transfected with specific siRNAs. The progress of ALS resulted in decreased P-Akt/Akt ratio, which is associated with increased proteins responsible for iron storage ferritin L, ferritin H, PCBP1, and skeletal muscle iron at ONSET. Conversely, proteins responsible for iron export- TAU significantly decrease. The training partially reverses changes in proteins responsible for iron metabolism. AKT silencing in the SH-SY5Y cell line decreased PCBP2 and ferroportin and increased ferritin L, H, PCBP1, TAU, transferrin receptor 1, and APP. Moreover, silencing APP led to an increase in ferritin L and H. Our data suggest that swim training in the mice ALS model is associated with significant changes in iron metabolism related to AKT activity. Down-regulation of AKT mainly upregulates proteins involved in iron import and storage but decreases proteins involved in iron export.

Insights Into the Role of Copper in Neurodegenerative Diseases and the Therapeutic Potential of Natural Compounds

Neurodegenerative diseases encompass a collection of neurological disorders originating from the progressive degeneration of neurons, resulting in the dysfunction of neurons. Unfortunately, effective therapeutic interventions for these diseases are presently lacking. Copper (Cu), a crucial trace element within the human body, assumes a pivotal role in various biological metabolic processes, including energy metabolism, antioxidant defense, and neurotransmission. These processes are vital for the sustenance, growth, and development of organisms. Mounting evidence suggests that disrupted copper homeostasis contributes to numerous age-related neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS), Wilson's disease (WD), Menkes disease (MD), prion diseases, and multiple sclerosis (MS). This comprehensive review investigates the connection between the imbalance of copper homeostasis and neurodegenerative diseases, summarizing pertinent drugs and therapies that ameliorate neuropathological changes, motor deficits, and cognitive impairments in these conditions through the modulation of copper metabolism. These interventions include Metal-Protein Attenuating Compounds (MPACs), copper chelators, copper supplements, and zinc salts. Moreover, this review highlights the potential of active compounds derived from natural plant medicines to enhance neurodegenerative disease outcomes by regulating copper homeostasis. Among these compounds, polyphenols are particularly abundant. Consequently, this review holds significant implications for the future development of innovative drugs targeting the treatment of neurodegenerative diseases.