Biology subjects

Horne, D.

Publications and source records attributed to Horne, D..

6 recordsLinked to original sources

bioRxiv2026

Development of CYP8B1-specific inhibitors for metabolic diseases

Changes in bile acids (BAs) balance lead to various metabolic diseases, yet current treatment options targeting these changes remain severely limited. CYP8B1 (cytochrome P450, family 8, subfamily B, polypeptide 1) is a liver-exclusive enzyme that controls the synthesis of 12-hydroxylated (12-OH) BAs. Inhibiting CYP8B1 is an attractive therapeutic strategy for attenuating 12-OH BA levels, remodeling the gut microbiota and thereby ameliorating metabolic diseases. CYP8B1-specific inhibitors are currently lacking due to structural similarities between the active site of CYP8B1 and other CYPs, and the lack of suitable high-throughput screening (HTS) assays. Herein, we developed a highly sensitive, and specific enzyme-coupled fluorescence assay to detect CYP8B1 activity, making it ideal for HTS. Employing this assay, structure-based drug design by protein X-ray crystallography, structure-activity relationship (SAR) analyses, and in vitro and in vivo validation, we developed novel CYP8B1-specific small molecule inhibitors. The lead candidate alters BA composition, favorably remodels the gut microbiota, and corrects metabolic disease in a metabolic dysfunction-associated steatotic liver disease (MASLD) mouse model. These findings reveal that pharmacologically inhibiting CYP8B1 is able to reshape the BA and gut microbiota profiles and effectively ameliorates metabolic diseases. Overall, CYP8B1-specific inhibitors represent a first-in-class promising, safe and effective therapeutic strategy against metabolic disorders.

pharmacology and toxicology↗

bioRxiv2026

Circadian Clock Control of Muscle Stem Cells Through Temporal Coordination of Notch and Wnt Signaling

The circadian clock regulates stem cell responses during tissue remodeling and repair. In skeletal muscle regeneration, successful regenerative myogenesis requires a temporally coordinated transition from Notch- to Wnt-driven signaling. However, the mechanisms governing this timing event remain poorly understood. Here, we show that circadian clock activity marks the cycling population of regeneration-activated myogenic progenitors that is induced in concert with Notch signaling. We identify key components of the Notch pathway as direct circadian clock targets and demonstrate that the clock coordinates Notch and Wnt signaling to drive myogenic progression. Genetic activation of the clock in satellite cells, as well as pharmacological clock stimulation, enhanced both proliferative expansion and subsequent differentiation of myogenic progenitors during regeneration. These effects were mediated by early activation of Notch signaling followed by increased Wnt pathway activity at later regenerative stages. Notably, both clock-dependent mechanisms remained functional in dystrophin-deficient mouse muscle and human myoblasts. Furthermore, clock-activating compounds enhanced regenerative myogenesis following acute injury and improved regeneration in dystrophic muscle. Collectively, these findings establish the circadian clock as a temporal regulator of regenerative signaling programs that orchestrate muscle repair with potential for targeted interventions.

cell biology↗

bioRxiv2026

Novel circadian clock activators display anti-obesity efficacy via suppression of adipocyte development and hypertrophy

The circadian clock exerts temporal coordination of metabolic processes to maintain homeostasis, and its disruption predisposes to the development of obesity and insulin resistance. Despite the established genetic basis of clock modulation in adipocyte development, whether it can be targeted for anti-obesity interventions remains to be explored. Here we report the novel actions of clock-activating molecules, chlorhexidine and a new derivative CM002, on inhibiting adipocyte development and hypertrophy that results in anti-obesity efficacy in vivo. Both chlorhexidine and CM002 were sufficient to activate clock in adipocytes with induction of core clock components and shortening of clock period length. Consistent with their clock-activating properties, these compounds suppressed the distinct lineage commitment and terminal differentiation stages of adipogenic precursor cells mediated via activation of the Wnt signaling pathway. Furthermore, CM002 attenuated lipid storage and adipocyte hypertrophy by suppressing the lipogenic and adipogenic program in a clock-dependent manner. Most importantly, CM002 administration in mice with diet-induced obesity was sufficient to induce clock activation in adipose depots, leading to robust suppression of adipogenic factors and lipogenic enzymes with marked effect on reducing fat mass and promoting insulin sensitivity. Collectively, our findings uncovered the anti-adipogenic properties of novel small molecule clock activators with demonstrated anti-obesity efficacy. These compounds provide novel chemical probes to dissect clock function in metabolic regulations with translational potential toward development of first-in-class clock-targeting drugs for anti-obesity therapy. HighlightsO_LIDiscovery of the anti-adipogenic properties of the clock activator chlorhexidine C_LIO_LIIdentification of a new clock-activating molecule CM002 C_LIO_LICM002 inhibits the lineage commitment and terminal differentiation of adipocytes C_LIO_LIClock activation by CM002 suppresses lipid storage in mature adipocytes C_LIO_LICM002 displays anti-obesity efficacy in diet-induced obesity model C_LI

physiology↗

bioRxiv2024

Epigenetic derepression of H3K9me3 mitigates Alzheimer-related pathology and improves cognition via immunomodulation and Vgf induction

We investigated the role of histone 3 lysine 9 trimethylation (H3K9me3), an epigenetic mechanism involved in the repression of synaptic plasticity and memory-related genes, within aging and Alzheimers disease (AD). Our study reveals that elevated cortical H3K9me3 strongly correlates with cognitive dysfunction in individuals with mild cognitive impairment (MCI) and AD. In old (18 months) and younger (14 months) APPSWE/PS1{Delta}E9 and 3xTg AD mouse models, inhibiting SUV39H1 methyltransferase with ETP69, substantially reduces cerebral H3K9me3 levels and attenuates amyloid-{beta} burden, tau pathology, and gliosis. Administration of ETP69 further promotes dendritic spine formation, leading to rapid and sustained improvements in cognitive function. Proteomics analysis indicates that a significant proportion of dysregulated proteins in the brains of AD-model mice are reversed by ETP69. These proteins are enriched for synaptic plasticity and learning-related pathways. ETP69 exerts its effects through multiple neuroprotective mechanisms, including regulation of neuroinflammation, induction of both blood and cerebral-infiltrating monocytes involved in cerebral A{beta} clearance. Moreover, ETP69 activates brain-derived neurotrophic factor (Bdnf) network, and particularly its downstream effector neurosecretory protein Vgf. These findings support the pharmacological inhibition of H3K9me3-mediated gene silencing to reverse AD-related pathology and cognitive decline.

neuroscience↗

bioRxiv2023

Anti-adipogenic properties of clock activator chlorhexidine and a new derivative

BackgroundThe circadian clock exerts temporal control of metabolic pathways to maintain homeostasis, and its disruption leads to the development of obesity and insulin resistance. In adipose tissue, key regulators of clock machinery orchestrate adipogenic processes via the Wnt signaling pathway to impact mature adipocyte development. MethodsBased on the recent finding of chlorhexidine as a new clock activator, we determined its potential anti-adipogenic activities in distinct adipogenic progenitor models. Furthermore, we report the structural optimization of chlorhexidine leading to the discovery of analogs with improved efficacy in inhibiting adipogenesis. ResultsIn adipogenic progenitors with Per2::dLuc luciferase reporter, Chlorhexidine shortened clock period length with induction of core clock components. Consistent with its clock-activating function, Chlorhexidine robustly suppressed the lineage commitment and maturation of adipogenic mesenchymal precursors, with comparable effect on inhibiting preadipocyte terminal differentiation. Mechanistically, we show that Chlorhexidine induces signaling components of the Wnt pathway resulting in activation of Wnt activity. Via modification of its chemical scaffold, we generated analogs of chlorhexidine that led to the identification of CM002 as a new clock- activating molecule with improved anti-adipogenic activity. ConclusionsCollectively, our findings uncovered the anti-adipogenic functions of a new class of small molecule clock activators. These compounds provide novel chemical probes to dissect clock function in maintaining metabolic homeostasis and may have therapeutic implications in obesity and associated metabolic disorders.

cell biology↗

bioRxiv2023

Targeted Screening and Identification of Chlorhexidine as a Pro-myogenic Circadian Clock Activator

BackgroundCircadian clock is an evolutionarily-conserved mechanism that exerts pervasive temporal control in stem cell behavior. This time-keeping machinery is required for orchestrating myogenic progenitor properties in regenerative myogenesis that ameliorates muscular dystrophy. Here we report a screening platform to discover circadian clock modulators that promote myogenesis, with the identification of chlorhexidine (CHX) as a clock-activating molecule with pro-myogenic activities. MethodsA high-throughput molecular docking pipeline was applied to identify candidate compounds with a structural fit for a hydrophobic pocket within the key circadian transcription factor protein, Circadian Locomotor Output Cycles Kaput (CLOCK). Secondary biochemical screen for clock-modulatory activities of these molecules were preformed, together with functional validations of myogenic regulations to identify modulators with pro-myogenic properties. ResultsCHX was identified as a clock activator that promotes distinct aspects of myogenesis. CHX activated circadian clock that reduced cycling period length and augmented amplitude. This action was mediated by the targeted CLOCK structure via augmented interaction with heterodimer partner Bmal1, leading to enhanced CLOCK/Bmal1-controlled transcription with up-regulation of core clock genes. Consistent with its clock-activating function, CHX displayed robust effects on stimulating myogenic differentiation in a clock-dependent manner. In addition, CHX augmented the proliferative and migratory activities of myoblasts. ConclusionOur findings demonstrate the feasibility of a screening platform to discover clock modulators with myogenic regulatory activities. Discovery of CHX as a pro-myogenic molecule could be applicable to promote regenerative capacities in ameliorating dystrophic or degenerative muscle diseases.

developmental biology↗