Simultaneous quantification of SMN1 and SMN2 copy numbers by MALDI-TOF mass spectrometry for spinal muscular atrophy genetic testing.

BACKGROUND: Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disorder caused by defects in the survival motor neuron 1 (SMN1) gene. Homozygous deletion of the SMN1 gene accounts for 95% of all affected SMA patients. A highly homologous gene survival motor neuron 2 (SMN2) compensates weakly with the loss of SMN1 and its copy number correlates with disease severity. METHODS: We report here the MS-CNV method combining competitive PCR and MALDI-TOF mass spectrometry for simultaneous quantification of SMN1, SMN2 and NAIP dosages. For both SMN1 and SMN2, the exon 7 and exon 8 were analyzed. MS-CNV was validated with parallel analysis by a commercial MLPA assay in two independent cohorts. RESULTS: In the first cohort of 79 blood samples containing 3 SMA patients and 5 carriers, MS-CNV results were highly concordant with MLPA analysis for the copy numbers of SMN1, SMN2 and NAIP. In the second independent and blinded cohort of 62 blood samples containing 21 SMA patients and 14 carriers, MS-CNV results were also highly concordant with MLPA. Both MS-CNV and MLPA quantified SMN1 dosages without ambiguity. CONCLUSIONS: MS-CNV can be used for carrier screening and genetic diagnosis of SMA, providing dosages information for both SMN1 and SMN2 given its accuracy and high sample processing throughput by mass spectrometric analysis.

Deuterium-Reinforced Polyunsaturated Fatty Acids Prevent Diet-Induced Nonalcoholic Steatohepatitis by Reducing Oxidative Stress.

Background and Objectives: Oxidative stress is implicated in the progression of nonalcoholic steatohepatitis (NASH) through the triggering of inflammation. Deuterium-reinforced polyunsaturated fatty acids (D-PUFAs) are more resistant to the reactive oxygen species (ROS)-initiated chain reaction of lipid peroxidation than regular hydrogenated (H-) PUFAs. Here, we aimed to investigate the impacts of D-PUFAs on oxidative stress and its protective effect on NASH. Materials and Methods: C57BL/6 mice were randomly divided into three groups and were fed a normal chow diet, a methionine-choline-deficient (MCD) diet, and an MCD with 0.6% D-PUFAs for 5 weeks. The phenotypes of NASH in mice were determined. The levels of oxidative stress were examined both in vivo and in vitro. Results: The treatment with D-PUFAs attenuated the ROS production and enhanced the cell viability in tert-butyl hydroperoxide (TBHP)-loaded hepatocytes. Concurrently, D-PUFAs decreased the TBHP-induced oxidative stress in Raw 264.7 macrophages. Accordingly, D-PUFAs increased the cell viability and attenuated the lipopolysaccharide-stimulated proinflammatory cytokine expression of macrophages. In vivo, the administration of D-PUFAs reduced the phenotypes of NASH in MCD-fed mice. Specifically, D-PUFAs decreased the liver transaminase activity and attenuated the steatosis, inflammation, and fibrosis in the livers of NASH mice. Conclusion: D-PUFAs may be potential therapeutic agents to prevent NASH by broadly reducing oxidative stress.