OLA-1, an Obg-like ATPase, integrates hunger with temperature information in sensory neurons in C. elegans

Hierarchical regulation of functionally antagonistic neuropeptides expressed in a single neuron pair

Neuronal communication involves small-molecule transmitters, gap junctions, and neuropeptides. While neurons often express multiple neuropeptides, our understanding of the coordination of their actions and their mutual interactions remains limited. Here, we demonstrate that two neuropeptides, NLP-10 and FLP-1, released from the same interneuron pair, AVKL/R, exert antagonistic effects on locomotion speed in Caenorhabditis elegans. NLP-10 accelerates locomotion by activating the G protein-coupled receptor NPR-35 on premotor interneurons that promote forward movement. Notably, we establish that NLP-10 is crucial for the aversive response to mechanical and noxious light stimuli. Conversely, AVK-derived FLP-1 slows down locomotion by suppressing the secretion of NLP-10 from AVK, through autocrine feedback via activation of its receptor DMSR-7 in AVK neurons. Our findings suggest that peptidergic autocrine motifs, exemplified by the interaction between NLP-10 and FLP-1, might represent a widespread mechanism in nervous systems across species. These mutual functional interactions among peptidergic co-transmitters could fine-tune brain activity.

Behavioral plasticity

Behavioral plasticity allows animals to modulate their behavior based on experience and environmental conditions. Caenorhabditis elegans exhibits experience-dependent changes in its behavioral responses to various modalities of sensory cues, including odorants, salts, temperature, and mechanical stimulations. Most of these forms of behavioral plasticity, such as adaptation, habituation, associative learning, and imprinting, are shared with other animals. The C. elegans nervous system is considerably tractable for experimental studies-its function can be characterized and manipulated with molecular genetic methods, its activity can be visualized and analyzed with imaging approaches, and the connectivity of its relatively small number of neurons are well described. Therefore, C. elegans provides an opportunity to study molecular, neuronal, and circuit mechanisms underlying behavioral plasticity that are either conserved in other animals or unique to this species. These findings reveal insights into how the nervous system interacts with the environmental cues to generate behavioral changes with adaptive values.

Obg-like ATPase 1 exacerbated gemcitabine drug resistance of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant disease with a poor prognosis due to inefficient diagnosis and tenacious drug resistance. Obg-like ATPase 1 (OLA1) is overexpressed in many malignant tumors. The molecular mechanism of OLA1 underlying gemcitabine (GEM)-induced drug resistance was investigated in this study. An enhanced expression of OLA1 was observed in a GEM acquired resistant pancreatic cancer cell lines and in patients with pancreatic cancer. Overexpressed OLA1 showed poor overall survival rates in patients with pancreatic cancer. Dysregulation of the OLA1 reduced expression of CD44+/CD133+, and improved the sensitivity of pancreatic cancer cells to GEM. OLA1 highly expression facilitated the formation of the OLA1/Sonic Hedgehog (SHH)/Hedgehog-interacting protein (HHIP) complex in nuclei, resulting in the inhibition of negative feedback of Hedgehog signaling induced by HHIP. This study suggests that OLA1 may be developed as an innovative drug target for an effective therapy of pancreatic cancer.

Analyses of Neural Circuits Governing Behavioral Plasticity in the Nematode Caenorhabditis elegans

Behavioral plasticity is subjected to various sensory stimuli, experiences, and physiological states, representing the temporal and spatial patterns of neural circuit dynamics. Elucidation of how genes and neural circuits in our brain actuate behavioral plasticity requires functional imaging during behavioral assays to manifest temporal and spatial neural regulation in behaviors. The exploration of the nervous systems of Caenorhabditis elegans has catalyzed substantial scientific advancements in elucidating the mechanistic link between circuit dynamics and behavioral plasticity. The analyses of the nervous system of C. elegans have technologically flourished owing to the development of optogenetic instruments and fluorescent protein-based imaging compatible with its optically transparent body and the understanding of its completely revealed neural connectome and gene expression profiles at single-neuron resolution (The C. elegans Neuronal Gene Expression Map & Network, CeNGEN project). Using examples of the two temperature learning behaviors in C. elegans, this chapter delves into a selection of pivotal imaging tools, including genetically encoded calcium indicators, biosensors for second messenger imaging, and their usage in freely moving worms that have propelled our grasp of sensory representation in C. elegans neural circuits. To further connect the circuit dynamics to behavioral plasticity, this chapter will focus on technological advancements enabling simultaneous imaging and tracking system together with methodologies to quantify multiple behavioral elements of freely behaving C. elegans in a dynamic environment.