Biology subjects

Rankin, C.

Publications and source records attributed to Rankin, C..

4 recordsLinked to original sources

bioRxiv2026

C. elegans Nuclear Hormone Receptor NHR-49 promotes attractive chemotaxis independently of its role in fatty acid metabolism

All organisms must sense and adapt to environmental cues to survive and thrive. In the nematode worm Caenorhabditis elegans, the nuclear hormone receptor nhr-49 is required for lipid homeostasis, stress resilience, pathogen defense, and longevity. In addition, recent studies suggest that NHR-49 controls avoidance behaviors and aversive memory to pathogenic bacteria and mitochondrial disruption, acting via its established role in fatty acid desaturation and fatty acid oxidation, respectively. However, the role of NHR-49 in neuronal signaling and behavior remains poorly understood. Here, we uncover a new role for NHR-49 in AWA neuron-mediated attractive chemotaxis. We show that nhr-49 is required for chemotaxis towards diacetyl and pyrazine, two AWA neuron-sensed compounds, but not for AWC- or ASH-mediated chemotaxis. Supplementation with unsaturated fatty acids and mutational analysis of additional genes involved in fatty acid desaturation or {beta}-oxidation reveal that these processes do not affect attractive chemotaxis; this suggests that NHR-49 mediates attractive chemotaxis independently of its role in fatty acid desaturation and oxidation. Tissue-specific expression of NHR-49 in neurons or body wall muscle is sufficient to rescue chemotaxis defects, while nhr-49 depletion in neurons alone causes chemotaxis defects. Finally, nhr-49 mutants also show defects in another behavior, the response and habituation to mechanosensory stimuli. Together, our data reveal new functions for NHR-49 in sensory responses and non-associative learning, which are distinct from its roles in aversive behaviors and memory and, notably, independent of its well-established role in lipid metabolism.

neuroscience↗

bioRxiv2026

CD163 protects against pulmonary injury and inflammation induced by acute O3 exposure

Ozone (O3)-driven pulmonary inflammation is partly regulated by damage associated molecular patterns (DAMPs) binding to scavenging receptors (SRs). However, how SRs and DAMPs regulate O3-induced pulmonary inflammation remains incompletely understood. CD163 is a SR responsible for clearing cell free hemoglobin (CFH), a DAMP which accumulates during acute pulmonary injury and is associated with worsening respiratory outcomes. We hypothesized that increased CD163 is necessary for reducing CFH levels and resolving O3-induced pulmonary injury. To test this hypothesis, we defined CD163 and CFH responses to O3 exposure in C57BL/6N (WT) and CD163 deficient (Cd163-/-) mice, as well as in human bronchoalveolar lavage fluid (BALF). In WT mice, lung Cd163 expression was significantly increased by O3 during peak inflammation and declined 24 hours post exposure. Human exposure studies revealed a diversity of Cd163 expression and a reduction of CFH following O3 exposure, suggesting regulation of this pathway in humans. When compared to WT mice, Cd163-/- mice had augmented O3-induced pulmonary injury, inflammation, and oxidative stress. Further, the antioxidant EUK-134 did not reduce O3-induced pulmonary oxidative stress in Cd163-/- mice, suggesting a role for CD163 in the pulmonary response to oxidative insults. Furthermore, compared to WT controls, Cd163-/- mice receiving an oropharyngeal aspiration of CFH had a significant increase in airspace inflammation. Combined, these findings suggest that CD163 mediated clearance of CFH is involved in resolving O3-induced pulmonary injury, inflammation, and oxidative stress. New & NoteworthyOzone (O3) is known to induce damage associated molecular patterns (DAMPs) which drive lung inflammation. The scavenging receptor, CD163, binds and clears the DAMP cell free hemoglobin (CFH), which accumulates during sterile lung injury. Our findings indicate that O3 exposure alters CD163 expression in the lung and that mice lacking Cd163 expression have more lung inflammation. Our data indicate that CD163 serves a protective role in response to acute O3 exposure perhaps through CFH clearance.

pharmacology and toxicology↗

bioRxiv2020

Peel-1 negative selection promotes screening-free CRISPR-Cas9 genome editing in Caenorhabditis elegans.

Improved genome engineering methods that enable automation of large and precise edits are essential for systematic investigations of genome function. We adapted peel-1 negative selection to an optimized Dual-Marker Selection (DMS) cassette protocol for CRISPR-Cas9 genome engineering in Caenorhabditis elegans and observed robust increases in multiple measures of efficiency that were consistent across injectors and four genomic loci. The use of Peel-1-DMS selection killed animals harboring transgenes as extrachromosomal arrays and spared genome edited integrants, often circumventing the need for visual screening to identify genome edited animals. To demonstrate the applicability of the approach, we created deletion alleles in the putative proteasomal subunit pbs-1 and the uncharacterized gene K04F10.3 and used machine vision to automatically characterize their phenotypic profiles, revealing homozygous essential and heterozygous behavioral phenotypes. These results provide a robust and scalable approach to rapidly generate and phenotype genome edited animals without the need for screening or scoring by eye. Author summaryThe ability to directly manipulate the genome and observe the resulting effects on the traits of an organism is a powerful approach to investigate gene function. CRISPR-based approaches to genome engineering have revolutionized such functional studies across model organisms but still face major challenges that limit the scope and complexity of projects that can be achieved in practice. Automating genome engineering and phenotyping would enable large-scale investigations of genome function in animals. Here, we describe the adaptation of peel-1 negative selection to an optimized dual-marker selection cassette CRISPR-Cas9 genome engineering method in C. elegans and combine it with automated machine vision phenotyping to achieve functional studies without the need for screening or scoring by eye. To demonstrate the applicability of the approach, we generated novel deletion alleles in two understudied genes, pbs-1 and K04F10.3, and used machine vision to characterize their phenotypic profiles, revealing homozygous lethal and heterozygous behavioral phenotypes. Our results open the door to systematic investigations of genome function in this model organism.

genomics↗

bioRxiv2019

Multi-model functionalization of disease-associated PTEN missense mutations identifies multiple molecular mechanisms underlying protein dysfunction

Functional variomics provides the foundation for personalized medicine by linking genetic variation to disease expression, outcome and treatment, yet its utility is dependent on appropriate assays to evaluate mutation impact on protein function. To fully assess the effects of 106 missense and nonsense variants of PTEN associated with autism spectrum disorder, somatic cancer and PHTS, we take a deep phenotypic profiling approach using 18 assays in 5 model systems spanning diverse cellular environments ranging from molecular function to neuronal morphogenesis and behavior. Variants inducing instability occurred across the protein, resulting in partial to complete loss of function (LoF), which was well correlated across models. However, assays were selectively sensitive to variants located in substrate binding and catalytic domains, which exhibited complete LoF or dominant negativity independent of effects on stability. Our results indicate that full characterization of variant impact requires assays sensitive to instability and a range of protein functions.

genetics↗