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He, L. S.

Publications and source records attributed to He, L. S..

3 recordsLinked to original sources

Multi-omic profiling of human and mouse dorsal root ganglia enables targeted gene delivery to nociceptors

Chronic pain conditions are often driven by hyperexcitability of nociceptors, the peripheral sensory neurons that detect noxious stimuli. Recent single-cell transcriptomic studies have begun to clarify the molecular identity of distinct peripheral sensory neuron subtypes, but tools that restrict transgene expression to nociceptors while sparing other dorsal root ganglion (DRG) subtypes remain limited. Here, we combined single-nucleus multi-omic profiling of human and mouse DRG with in vivo AAV enhancer screening to identify cis-regulatory elements that drive biased AAV expression in mouse DRG nociceptors and human iPSC-derived nociceptors. We then validated that an enhancer AAV designed to express Kir2.1 preferentially in nociceptors reduces DRG neuronal excitability. Leveraging these multi-omic datasets, we trained a sequence-based model to decode the cis-regulatory logic of nociceptors, enabling both the prioritization of native candidate elements and the design of synthetic enhancers with a range of nociceptor targeting properties. Together, these cross-species multi-omic resources define conserved DRG regulatory programs and provide a viral toolkit for pain research with potential translational applications for patients with refractory pain.

neuroscience↗

Molecular tuning of sea anemone stinging

Jellyfish and sea anemones fire single-use, venom-covered barbs to immobilize prey or predators. We previously showed that the anemone Nematostella vectensis uses a specialized voltage-gated calcium (CaV) channel to trigger stinging in response to synergistic prey-derived chemicals and touch (Weir et al., 2020). Here we use experiments and theory to find that stinging behavior is suited to distinct ecological niches. We find that the burrowing anemone Nematostella uses uniquely strong CaV inactivation for precise control of predatory stinging. In contrast, the related anemone Exaiptasia diaphana inhabits exposed environments to support photosynthetic endosymbionts. Consistent with its niche, Exaiptasia indiscriminately stings for defense and expresses a CaV splice variant that confers weak inactivation. Chimeric analyses reveal that CaV{beta} subunit adaptations regulate inactivation, suggesting an evolutionary tuning mechanism for stinging behavior. These findings demonstrate how functional specialization of ion channel structure contributes to distinct organismal behavior.

physiology↗

Rapid adaptation to elevated extracellular potassium in the pyloric circuit of the crab, Cancer borealis

Elevated [K+] is often used to alter excitability in neurons and networks by shifting the potassium equilibrium potential (EK) and, consequently, the resting membrane potential. We studied the effects of increased extracellular [K+] on the well-described pyloric circuit of the crab, Cancer borealis. A 2.5-fold increase in extracellular [K+] (2.5x[K+]) depolarized Pyloric Dilator (PD) neurons and resulted in short-term loss of their normal bursting activity. This period of silence was followed within 5-10 minutes by the recovery of spiking and/or bursting activity during continued superfusion of 2.5x[K+] saline. In contrast, when PD neurons were pharmacologically isolated from pyloric presynaptic inputs, they exhibited no transient loss of spiking activity in 2.5x[K+], suggesting the presence of an acute inhibitory effect mediated by circuit interactions. Action potential threshold in PD neurons hyperpolarized during an hour-long exposure to 2.5x[K+] concurrent with the recovery of spiking and/or bursting activity. Thus, the initial loss of activity appears to be mediated by synaptic interactions within the network, but the secondary adaptation depends on changes in the intrinsic excitability of the pacemaker neurons. The complex sequence of events in the responses of pyloric neurons to elevated [K+] demonstrates that electrophysiological recordings are necessary to determine both the transient and longer-term effects of even modest alterations of K+ concentrations on neuronal activity. Significance StatementSolutions with elevated extracellular potassium are commonly used as a depolarizing stimulus. Moreover, hyperkalemia is associated with a number of disease states, including epileptic seizures and brain traumas. We studied the effects of high [K+] saline on the well-described pyloric circuit of the crab stomatogastric ganglion. A 2.5-fold increase in extracellular [K+] led to a transient loss of activity in pyloric neurons that was not due to depolarization block. This was followed by a rapid increase in excitability and concurrent recovery of spiking and rhythmic bursting activity within minutes. These results suggest that effects of high [K+] on neuronal circuits can be complex and non-stationary.

neuroscience↗