Neurocellular Stress Response to Mojave Type A Rattlesnake Venom: Study of Molecular Mechanisms Using Human iPSC-Derived Neural Stem Cell Model.

The Mojave rattlesnake venom shows significant geographical variability. The venom of Type A animals primarily contains β-neurotoxin referred to as Mojave Toxin (MTX), which makes bites from this snake particularly feared. We performed a genome-wide transcriptomic analysis of the neurocellular response to Mojave Type A rattlesnake venom using induced pluripotent stem cell-derived neural stem cells to unveil the molecular mechanisms underlying the damage caused by this snake's envenomation. Our results suggest that snake venom metalloproteases, although having a limited repertoire in Type A venom, facilitate venom spread by digesting the tissue's extracellular matrix. The MTX, which is composed of heterodimers of basic and acidic phospholipase-A2, co-opts the host arachidonic acid and Ca second messenger mechanisms and triggers multiple signaling cascades, such as the activation of MAPKs and NF-κB-regulated proinflammatory genes; the neurotransmitter overload in excitatory synapses leading to a presynaptic blockade of nerve signals; and the upregulation of unfolded protein response (UPR) due to the depletion of Ca from the endoplasmic reticulum. The upregulated UPR and the oxidative stress caused by reactive oxygen species generated in cytochromeP4501A1-mediated hydroxylation of arachidonic acid contribute to mitochondrial toxicity. The activation of UPR, mitochondrial toxicity, and oxidative stress synergistically contributed to apoptotic and ferroptotic cell death.