N‐acetylcysteine normalizes the urea cycle and DNA repair in cells from patients with Batten disease

Abstract

Batten disease is an inherited disorder characterized by early onset neurodegeneration due to the mutation of the CLN3 gene. The function of the CLN3 protein is not clear, but an association with oxidative stress has been proposed. Oxidative stress and DNA damage play critical roles in the pathogenesis of neurodegenerative diseases. Antioxidants are of interest because of their therapeutic potential for treating neurodegenerative diseases. We tested whether N-acetylcysteine (NAC), a well-known antioxidant, improves the pathology of cells from patients with Batten disease. At first, the expression levels of urea cycle components and DNA repair enzymes were compared between Batten disease cells and normal cells. We used both mRNA expression levels and Western blot analysis. We found that carbamoyl phosphate synthetase 1, an enzyme involved in the urea cycle, 8-oxoguanine DNA glycosylase 1 and DNA polymerase beta, enzymes involved in DNA repair, were expressed at higher levels in Batten disease cells than in normal cells. The treatment of Batten disease cells with NAC for 48 h attenuated activities of the urea cycle and of DNA repair, as indicated by the substantially decreased expression levels of carbamoyl phosphate synthetase 1, 8-oxoguanine DNA glycosylase 1 and DNA polymerase beta proteins compared with untreated Batten cells. NAC may serve in alleviating the burden of urea cycle and DNA repair processes in Batten disease cells. We propose that NAC may have beneficial effects in patients with Batten disease.

Molecular networking in the neuronal ceroid lipofuscinoses: insights from mammalian models and the social amoeba Dictyostelium discoideum

“…Mutations in SLC25A13 cause citrullinemia, an autosomal recessive disease characterized by elevated levels of ammonia in the blood, which leads to neuropsychiatric symptoms such as abnormal behaviour, memory loss, seizures, and even death [73]. Importantly, mitochondrial dysfunction has been reported in the NCLs and there is evidence supporting altered ammonia homeostasis in at least one subtype of the disease (e.g., CLN3 disease) [74][75][76]. Together, these findings suggest that further investigation into the involvement of DBH, SLC25A1, and SLC25A13 in NCL pathology is warranted.…”

An altered secretome is an early marker of the pathogenesis of CLN6 Batten disease

“…Cellular models of NCLs are commonly used to understand cellular biology (Minnis et al., 2019), and as platforms for therapeutic efficacy studies (Gavin et al., 2013; Kim et al., 2012; Linterman et al., 2011). In this study we used mass spectrometry (MS) based secretome profiling to characterise disease specific changes in primary cortical cell cultures of neurons, microglia, and astrocytes derived from the Cln6 nclf mouse.…”

Progress in the Development of Small Molecule Therapeutics for the Treatment of Neuronal Ceroid Lipofuscinoses (NCLs)

“…Treatment with N -acetylcysteine ( 6 ), a known antioxidant, precursor, and analogue of glutathione, reduced expression levels of CPS1, OGG1, and DNA polymerase β in cells derived from Batten disease patients. 45 A pilot study was conducted in nine INCL patients to determine the beneficial effects of combination of cysteamine bitartrate and N -acetylcysteine. Decrease in the number and size of GRODs was observed after the first posttreatment follow-up and in the subsequent follow-up GROD levels were undetectable indicating that the treatment had beneficial effects in patients.…”

“…Several phenotypic models mimicking the NCL disease state in humans have been developed to aid drug discovery efforts and to help determine the underlying pathophysiology. Several researchers have reported the use of NCL patient lymphoblasts and fibroblasts, along with neurons derived from animal models of NCL disease. − A phenotypic model of the human neuroblastoma cell line SH-SY5Y was developed using siRNA knockdown of the CLN3 gene, the gene known to mutate in JNCL . A similar model was developed in primary rat cortical neurons by CLN3 knockdown using a siRNA based method .…”

“…Increased levels of biomarkers including carbamoyl phosphate synthetase 1 (CPS1), 8-oxoguanine DNA glycosylase 1 (OGG1), and DNA polymerase β were observed in NCL patient lymphoblasts. Treatment with N -acetylcysteine ( 6 ), a known antioxidant, precursor, and analogue of glutathione, reduced expression levels of CPS1, OGG1, and DNA polymerase β in cells derived from Batten disease patients . A pilot study was conducted in nine INCL patients to determine the beneficial effects of combination of cysteamine bitartrate and N -acetylcysteine.…”