TRPV4 Deficiency Shifts Mitochondrial Dynamics Toward a Fragmented Morphology in Primary Microglia

Microglia perform surveillance and phagocytosis to maintain the homeostasis of the central nervous system (CNS). These processes are energetically demanding, and given the critical roles of mitochondria in providing ATP, the characteristics of the mitochondrial network can modulate microglial behavior. Although the Ca²⁺-permeable Transient Receptor Potential Vanilloid 4 (TRPV4) is known for regulating microglial morphology and migration, and it is implicated in mitochondrial calcium uptake, it is unknown whether TRPV4 affects the mitochondrial network in microglia. Our study provides evidence that TRPV4 plays a role in the integrity and complexity of the mitochondrial network in microglia. Quantification of the Mitochondrial Fragmentation and Complexity Index (MFCI) and increased pDrp1 (Ser616) showed a shift towards mitochondrial network fragmentation, and lowered complexity in <i>Trpv4</i> knockout versus wild-type primary murine microglia in vitro. The distribution of mitochondria within microglia showed significant differences in density at 10-32 µm away from the nucleus. Furthermore, acute pharmacological TRPV4 inhibition with GSK2193874 did not induce significant mitochondria network fragmentation. Our findings establish TRPV4 as a regulator of mitochondrial dynamics and adaptive responses, highlighting its importance for maintaining homeostasis in microglia and the entire CNS.