Dopamine‐related oxidative stress and mitochondrial dysfunction in dopaminergic neurons differentiated from deciduous teeth‐derived stem cells of children with Down syndrome

Down syndrome child with multiple heart diseases: A case report

BACKGROUND

Down syndrome, also known as trisomy 21 syndrome, is commonly associated with congenital heart disease, and can often result in early formation of pulmonary hypertension. The development of pulmonary hypertension can result from factors such as intracardiac and macrovascular shunts, and upper airway obstruction or hypoplasia of lung tissue. Individuals with Down syndrome and congenital heart disease have a significantly lower average life expectancy, with surgical intervention being the most viable treatment option to improve longevity.

CASE SUMMARY

We report the case of a 13-year-old boy with Down syndrome presenting with atrial septal defect and patent ductus arteriosus along with severe pulmonary hypertension. The electrocardiogram shows sinus rhythm and right ventricular hypertrophy. The echocardiogram shows an atrial septal defect with interrupted echo in the interatrial septum, measuring 0.813 cm in length. The patient was initially refused to be offered surgical treatment by many hospitals due to the high surgical risk and pulmonary artery resistance. After discussing the patient's diagnosis and treatment options, we ultimately recommended surgical treatment. However, the patient and their family declined this recommendation and chose to be discharged. During the follow-up period of 6 mo, there were no significant improvements or deteriorations in the patient's condition.

CONCLUSION

In conclusion, this case highlights the challenges faced by individuals with Down syndrome and congenital heart disease complicated by severe pulmonary hypertension. Timely intervention and a multidisciplinary approach are crucial for improving prognosis and life expectancy. Further research is needed to enhance our understanding and develop effective interventions for this population.

Mitochondrial Calcium-Triggered Oxidative Stress and Developmental Defects in Dopaminergic Neurons Differentiated from Deciduous Teeth-Derived Dental Pulp Stem Cells with MFF Insufficiency

Mitochondrial fission factor (MFF) is an adapter that targets dynamin-related protein 1 from the cytosol to the mitochondria for fission. Loss-of-function MFF mutations cause encephalopathy due to defective mitochondrial and peroxisomal fission 2 (EMPF2). To elucidate the molecular mechanisms that were involved, we analyzed the functional effects of MFF depletion in deciduous teeth-derived dental pulp stem cells differentiating into dopaminergic neurons (DNs). When treated with MFF-targeting small interfering RNA, DNs showed impaired neurite outgrowth and reduced mitochondrial signals in neurites harboring elongated mitochondria. MFF silencing also caused mitochondrial Ca²⁺ accumulation through accelerated Ca²⁺ influx from the endoplasmic reticulum (ER) via the inositol 1,4,5-trisphosphate receptor. Mitochondrial Ca²⁺ overload led DNs to produce excessive reactive oxygen species (ROS), and downregulated peroxisome proliferator-activated receptor-gamma co-activator-1 alpha (PGC-1α). MFF was co-immunoprecipitated with voltage-dependent anion channel 1, an essential component of the ER-mitochondrial Ca²⁺ transport system. Folic acid supplementation normalized ROS levels, PGC-1α mediated mitochondrial biogenesis, and neurite outgrowth in MFF depleted DNs, without affecting their mitochondrial morphology or Ca²⁺ levels. We propose that MFF negatively regulates the mitochondrial Ca²⁺ influx from the ER. MFF-insufficiency recapitulated the EMPF2 neuropathology with increased oxidative stress and suppressed mitochondrial biogenesis. ROS and mitochondrial biogenesis might be potential therapeutic targets for EMPF2.