Plasma Homocysteine and Polymorphisms of Genes Involved in Folate Metabolism Correlate with DNMT1 Gene Methylation Levels

Association of Increased Homocysteine Levels with Impaired Folate Metabolism and Vitamin B Deficiency in Early-Onset Multiple Sclerosis

The contents of homocysteine (HCy), cyanocobalamin (vitamin B12), folic acid (vitamin B9), and pyridoxine (vitamin B6) were analyzed and the genotypes of the main gene polymorphisms associated with folate metabolism (C677T and A1298C of the MTHFR gene, A2756G of the MTR gene and A66G of the MTRR gene) were determined in children at the onset of multiple sclerosis (MS) (with disease duration of no more than six months), healthy children under 18 years (control group), healthy adults without neurological pathology, adult patients with MS at the onset of disease, and adult patients with long-term MS. A significant increase in the HCy levels was found in children at the MS onset compared to healthy children of the corresponding age. It was established that the content of HCy in children has a high predictive value. At the same time, an increase in the HCy levels was not accompanied by the deficiency of vitamins B6, B9, and B12 in the blood. The lack of correlation between the laboratory signs of vitamin deficiency and HCy levels may be due to the polymorphic variants of folate cycle genes. An increased HCy level should be considered as a marker of functional disorders of folate metabolism accompanying the development of pathological process in pediatric MS. Our finding can be used to develop new approaches to the prevention of demyelination in children and treatment of pediatric MS.

A Paternal Methylation Error in the Congenital Hydrocephalic Texas (H-Tx) Rat Is Partially Rescued with Natural Folate Supplements

Folate deficiencies, folate imbalance and associated abnormal methylation are associated with birth defects, developmental delays, neurological conditions and diseases. In the hydrocephalic Texas (H-Tx) rat, 10-formyl tetrahydrofolate dehydrogenase (FDH) is reduced or absent from the CSF and the nuclei of cells in the brain and liver and this is correlated with decreased DNA methylation. In the present study, we tested whether impaired folate metabolism or methylation exists in sexually mature, unaffected H-Tx rats, which may explain the propagation of hydrocephalus in their offspring. We compared normal Sprague Dawley (SD, n = 6) rats with untreated H-Tx (uH-Tx, n = 6 and folate-treated H-Tx (TrH-Tx, n = 4). Structural abnormalities were observed in the testis of uH-Tx rats, with decreased methylation, increased demethylation, and cell death, particularly of sperm. FDH and FRα protein expression was increased in uH-Tx males but not in folate-treated males but tissue folate levels were unchanged. 5-Methylcytosine was significantly reduced in untreated and partially restored in treated individuals, while 5-hydroxymethylcytosine was not significantly changed. Similarly, a decrease in DNA-methyltransferase-1 expression in uH-Tx rats was partially reversed with treatment. The data expose a significant germline methylation error in unaffected adult male H-Tx rats from which hydrocephalic offspring are obtained. Reduced methylation in the testis and sperm was partially recovered by treatment with folate supplements leading us to conclude that this neurological disorder may not be completely eradicated by maternal supplementation alone.

Homocysteine induces oxidative stress and ferroptosis of nucleus pulposus via enhancing methylation of GPX4

Homocysteine (Hcy) is an amino acid involved in gene methylation. Plasma concentration of Hcy is elevated in the pathological condition hyperhomocysteinemia (HHcy), which increases the risk of disorders of the vascular, nervous and musculoskeletal systems, including chondrocyte dysfunction. The present study aimed to explore the role of Hcy in intervertebral disc degeneration (IVDD), using a range of techniques. A clinical epidemiological study showed that HHcy is an independent risk factor for human IVDD. Cell culture using rat nucleus pulposus cells showed that Hcy promotes a degenerative cell phenotype (involving increased oxidative stress and cell death by ferroptosis) which is mediated by upregulated methylation of GPX4. An in-vivo mouse 'puncture' model of IVDD showed that folic acid (which is used to treat HHcy in humans) reduced the ability of diet-induced HHcy to promote IVDD. We conclude that Hcy upregulates oxidative stress and ferroptosis in the nucleus pulposus via enhancing GPX4 methylation, and is a new contributing factor in IVDD.