Effects of mitochondrial complex I subunit NDUFS5 deficiency on osteogenic differentiation

Area of Science:

• Cell Biology
• Biochemistry
• Metabolism

Background:

• Mitochondrial complex I is crucial for cellular energy production and homeostasis.
• Osteogenic differentiation, the process of bone formation, relies on mitochondrial function.
• The role of NADH:ubiquinone oxidoreductase core subunit (NDUFS5) in osteoblast differentiation is not well understood.

Purpose of the Study:

• To investigate the role of NDUFS5 in osteogenic differentiation.
• To determine if NDUFS5 deficiency impairs osteoblast differentiation via mitochondrial dysfunction.
• To explore the involvement of the gamma-aminobutyric acid (GABA) shunt in NDUFS5-mediated metabolic disruption during osteogenesis.

Main Methods:

• NDUFS5 expression analysis in mouse bone and osteoblast cell lines.
• Assessment of osteogenic differentiation markers and alkaline phosphatase (ALP) activity.
• Evaluation of mitochondrial morphology, membrane potential, reactive oxygen species (ROS), and oxygen consumption.
• Integrated transcriptomic and metabolomic profiling, with exogenous GABA supplementation experiments.

Main Results:

• NDUFS5 expression increased during osteogenic differentiation.
• NDUFS5 deficiency led to reduced osteogenic markers and ALP activity.
• Mitochondrial dysfunction, including swelling and impaired respiration, was observed in NDUFS5-deficient cells.
• GABA shunt disruption and reduced intracellular GABA were identified, with partial rescue by exogenous GABA.

Conclusions:

• NDUFS5 is essential for maintaining mitochondrial integrity and function during osteogenic differentiation.
• NDUFS5 plays a critical role in metabolic homeostasis through the GABA shunt pathway.
• Targeting NDUFS5-associated mitochondrial metabolism and GABA shunt may offer therapeutic strategies for bone healing.