Marine and Anthropogenic Bromopyrroles Alter Cellular Ca Dynamics of Murine Cortical Neuronal Networks by Targeting the Ryanodine Receptor and Sarco/Endoplasmic Reticulum Ca-ATPase.

Bromopyrroles (BrPyr) are synthesized naturally by marine sponge symbionts and produced anthropogenically as byproducts of wastewater treatment. BrPyr interact with ryanodine receptors (RYRs) and sarco/endoplasmic reticulum (SR/ER) Ca-ATPase (SERCA). Influences of BrPyr on the neuronal network activity remain uncharted. BrPyr analogues with differing spectra of RYR/SERCA activities were tested using RYR-null or RYR1-expressing HEK293 and murine cortical neuronal/glial cocultures (NGCs) loaded with Fluo-4 to elucidate their mechanisms altering Ca dynamics. The NGC electrical spike activity (ESA) was measured from NGCs plated on multielectrode arrays. Nanomolar tetrabromopyrrole (TBP, ) potentiated caffeine-triggered Ca release independent of extracellular [Ca] in RYR1-HEK293, whereas higher concentrations produce slow and sustained rise in cytoplasmic [Ca] independent of RYR1 expression. TBP, 2,3,5-tribromopyrrole (), pyrrole (), 2,3,4-tribromopyrrole (), and ethyl 4-bromopyrrole-2-carboxylate () added acutely to NGC showed differential potency; rank order (IC ≈ 220 nM) > ≫ , whereas and were inactive at 10 μM. >2 μM elicited sustained elevation of cytoplasmic [Ca] and loss of neuronal viability. did not alter network ESA. BrPyr from marine and anthropogenic sources are ecological signaling molecules and emerging anthropogenic pollutants of concern to environmental and human health that potently alter ER Ca dynamics and warrant further investigation .