Cerebrospinal Fluid Levels of Lysophosphatidic Acids Can Provide Suitable Biomarkers of Blast-Induced Traumatic Brain Injury

Lysophosphatidic acid contributes to myocardial ischemia/reperfusion injury by activating TRPV1 in spinal cord

Lysophosphatidic acid (LPA) is a bioactive phospholipid that plays a crucial role in cardiovascular diseases. Here, we question whether LPA contributes to myocardial ischemia/reperfusion (I/R) injury by acting on transient receptor potential vanilloid 1 (TRPV1) in spinal cord. By ligating the left coronary artery to establish an in vivo I/R mouse model, we observed a 1.57-fold increase in LPA level in the cerebrospinal fluid (CSF). The I/R-elevated CSF LPA levels were reduced by HA130, an LPA synthesis inhibitor, compared to vehicle treatment (4.74 ± 0.34 vs. 6.46 ± 0.94 μg/mL, p = 0.0014). Myocardial infarct size was reduced by HA130 treatment compared to the vehicle group (26 ± 8% vs. 46 ± 8%, p = 0.0001). To block the interaction of LPA with TRPV1 at the K710 site, we generated a K710N knock-in mouse model. The TRPV1K710N mice were resistant to LPA-induced myocardial injury, showing a smaller infarct size relative to TRPV1WT mice (28 ± 4% vs. 60 ± 7%, p < 0.0001). Additionally, a sequence-specific TRPV1 peptide targeting the K710 region produced similar protective effects against LPA-induced myocardial injury. Blocking the K710 region through K710N mutation or TRPV1 peptide resulted in reduced neuropeptides release and decreased activity of cardiac sensory neurons, leading to a decrease in cardiac norepinephrine concentration and the restoration of intramyocardial pro-survival signaling, namely protein kinase B/extracellular regulated kinase/glycogen synthase kinase-3β pathway. These findings suggest that the elevation of CSF LPA is strongly associated with myocardial I/R injury. Moreover, inhibiting the interaction of LPA with TRPV1 by blocking the K710 region uncovers a novel strategy for preventing myocardial ischemic injury.