Biology subjects

Kawana, M.

Publications and source records attributed to Kawana, M..

3 recordsLinked to original sources

bioRxiv2026

Early detection of pancreatic ductal adenocarcinoma by single-molecule profiling of pancreatic enzyme activities

Pancreatic ductal adenocarcinoma (PDAC) remains a leading cause of cancer-related mortality, largely due to diagnosis at advanced stages. Early detection through minimally invasive liquid biopsy holds promise for improving patient outcomes. Here, we report a blood-based liquid biopsy platform based on single-molecule enzyme activity profiling (SEAP), which detects proteoform-level alterations in circulating pancreatic enzymes at single-molecule resolution. Using a tissue-centric biomarker discovery strategy, we identified activity signatures of pancreas-specific digestive enzymes associated with PDAC. A combinatorial classifier detected PDAC (stage I-IV) with 95.5% specificity and 75.0% sensitivity (74.2% for stage I-II) across 690 blood samples collected from multiple hospitals and biobanks. Performance was further validated in an independent cohort enriched for early-stage disease, where 54.2% (13/24) of stage IA, 64.3% (9/14) of stage IB, and 21.4% (3/14) of stage 0 lesions were classified as positive. These findings support the clinical potential of SEAP for early detection of PDAC.

biochemistry↗

bioRxiv2025

Spatial genomics of the cardiac sarcomere

Structure-function mapping of proteins has improved our understanding of disease mechanisms and protein domains while human population genetics has provided a window into variational tolerance that can be modeled at a structural level. Here, to reveal novel insight into the cardiac sarcomere, the motor unit of the heart, we develop a novel analytical framework to integrate data from over 17,000 patients with hypertrophic cardiomyopathy (HCM) and combine it with two population-scale genomic databases that incorporate data from more than 800,000 individuals. We integrate in silico genetic predictions of gene variant pathogenicity with 3 dimensional integrative spatial scanning across multiple structural models of cardiac motor proteins. Results reveal both recognized and novel regions of structural variant intolerance across the critical genes of the cardiac sarcomere including novel insights into protein function. We discuss the structural relevance of variant enrichment in the context of sarcomere organization and destabilization of sequestered myosin leading to hypercontractility seen in HCM, by incorporating the recently defined high-resolution structure of human cardiac myosin filament. We extend and validate these findings through pathogenic variant class enrichment and reveal novel associations with the earlier onset of disease in a large clinical cohort. In summary, our study provides a multi-dimensional framework for integrating structural, genomic, and modeling data to reveal novel insight into the cardiac sarcomere.

genomics↗

bioRxiv2018

Controlling load-dependent contractility of the heart at the single molecule level

Concepts in molecular tension sensing in biology are growing and have their origins in studies of muscle contraction. In the heart muscle, a key parameter of contractility is the detachment rate from actin of myosin, which determines the time that myosin is bound to actin in a force-producing state and, importantly, depends on the load (force) against which myosin works. Here, we measure the detachment rate of single molecules of human {beta}-cardiac myosin and its load dependence. We find that both can be modulated by both small molecule compounds and cardiomyopathy-causing mutations. Furthermore, effects of mutations can be reversed by introducing appropriate compounds. Our results suggest that activating vs. inhibitory perturbations of cardiac myosin are discriminated by the aggregate result on duty ratio, average force, and ultimately average power output and that cardiac contractility can be controlled by tuning the load-dependent kinetics of single myosin molecules.

biophysics↗