The glutamatergic neurotransmitter system has received substantial attention in research on the pathophysiology and treatment of neurological disorders. The study investigated the effect of the polyphenolic compound chlorogenic acid (CGA) on glutamate release in rat cerebrocortical nerve terminals (synaptosomes). CGA inhibited 4-aminopyridine (4-AP)-induced glutamate release from synaptosomes. This inhibition was prevented in the absence of extracellular Ca2+ and was associated with the inhibition of 4-AP-induced elevation of Ca2+ but was not attributed to changes in synaptosomal membrane potential. In line with evidence observed through molecular docking, CGA did not inhibit glutamate release in the presence of P/Q-type Ca2+ channel inhibitors; therefore, CGA-induced inhibition of glutamate release may be mediated by P/Q-type Ca2+ channels. CGA-induced inhibition of glutamate release was also diminished by the calmodulin and Ca2+/calmodilin-dependent kinase II (CaMKII) inhibitors, and CGA reduced the phosphorylation of CaMKII and its substrate, synapsin I. Furthermore, pretreatment with intraperitoneal CGA injection attenuated the glutamate increment and neuronal damage in the rat cortex that were induced by kainic acid administration. These results indicate that CGA inhibits glutamate release from cortical synaptosomes by suppressing P/Q-type Ca2+ channels and CaMKII/synapsin I pathways, thereby preventing excitotoxic damage to cortical neurons.

Junctional adhesion molecule 3 (JAM3) involved in epithelial cell junction, cell polarity and motility. The molecular mechanisms underlying the role of JAM3 in placental dysfunction remain unclear. We hypothesized that JAM3 expression regulates trophoblast fusion, differentiation, proliferation, and apoptosis. Our results revealed that JAM3 was expressed in the cytotrophoblasts and syncytiotrophoblasts of first-trimester and term placental villi. JAM3 expression in cell–cell junctions decreased with the formation of syncytiotrophoblasts. Using trophoblasts as an in vitro model, we observed that forskolin and JAM3 knockdown significantly reduced JAM3 expression and increased syncytium formation. JAM3 knockdown additionally inhibited trophoblast proliferation and increased the number of trophoblasts in the sub-G1 and G2/M phases, indicating cell cycle disturbance and apoptosis. Cell cycle arrest was associated with the engagement of Checkpoint kinase 2–cell division cycle 25C–Cyclin-dependent kinase 1/Cyclin B1 signaling. Increased expression of BIM, NOXA, XAF1, cytochrome c, and cleaved caspase-3 further indicated trophoblast apoptosis. Overexpression of JAM3 or recombinant JAM3 protein enhanced trophoblast adhesion and migration, which were inhibited by JAM3 knockdown. JAM3 knockdown induced reactive oxygen species and syncytin 2 expression in trophoblasts. Furthermore, H2O2-induced oxidative stress reduced JAM3 expression in trophoblasts and cell culture supernatants. H2O2 simultaneously induced trophoblast apoptosis. JAM3 expression was significantly decreased in the plasmas and placentas of patients with early-onset severe preeclampsia. Thus, our results demonstrate that JAM3 may not only be a structural component of trophoblast cell junctions but also regulate trophoblast fusion, differentiation, proliferation, apoptosis, and motility. Dysregulated trophoblast JAM3 expression is crucial in preeclampsia development.

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