Coupling calcium dynamics and mitochondrial bioenergetic: an in silico study to simulate cardiomyocyte dysfunction

Area of Science:

• Cardiology
• Mitochondrial Physiology
• Computational Biology

Background:

• The interplay between intracellular calcium (Ca2+) dynamics and mitochondrial bioenergetics is vital for cardiomyocyte function.
• Cardiomyocyte dysfunction (CD) is often linked to reduced ATP production and elevated mitochondrial calcium ([Ca2+]m).
• Therapeutic strategies targeting [Ca2+]m reduction are being explored, but its causal role in CD remains debated.

Purpose of the Study:

• To investigate whether mitochondrial calcium ([Ca2+]m) overload is a direct pathological trigger or a consequence of cardiomyocyte dysfunction (CD).
• To explore the mechanisms by which mitochondria handle calcium under impaired conditions.
• To identify potential therapeutic targets for restoring cardiomyocyte function.

Main Methods:

• In silico modeling and simulation of cardiomyocyte bioenergetics and calcium dynamics.
• Recalibration of model parameters to simulate mitochondrial responses to functional impairments.
• Analysis of the coupling between [Ca2+]m oscillations and ATP synthesis rate.

Main Results:

• Computational models suggest that [Ca2+]m overload may not be the direct cause of CD.
• Mitochondria accumulate calcium as a consequence of coping with functionally impaired processes.
• A strong coupling between [Ca2+]m oscillations and ATP synthesis rate is crucial for maintaining robust calcium cycling and preventing CD.

Conclusions:

• Mitochondrial calcium accumulation appears to be a consequence, not a direct cause, of cardiomyocyte dysfunction.
• The mitochondrial calcium uniporter may play a cardioprotective role.
• Targeting the mitochondrial sodium-calcium exchanger could be a viable therapeutic strategy for CD.