William Richardson

Zhao Zhang, Xiwen Chen, William Richardson et al.

Decreased myocardial capillary density has been reported as an important histopathological feature associated with various heart disorders. Quantitative assessment of cardiac capillarization typically involves double immunostaining of cardiomyocytes (CMs) and capillaries in myocardial slices. In contrast, single immunostaining of basement membrane components is a straightforward approach to simultaneously label CMs and capillaries, presenting fewer challenges in background staining. However, subsequent image analysis always requires manual work in identifying and segmenting CMs and capillaries. Here, we developed an image analysis tool, AutoQC, to automatically identify and segment CMs and capillaries in immunofluorescence images of collagen type IV, a predominant basement membrane protein within the myocardium. In addition, commonly used capillarization-related measurements can be derived from segmentation masks. AutoQC features a weakly supervised instance segmentation algorithm by leveraging the power of a pre-trained segmentation model via prompt engineering. AutoQC outperformed YOLOv8-Seg, a state-of-the-art instance segmentation model, in both instance segmentation and capillarization assessment. Furthermore, the training of AutoQC required only a small dataset with bounding box annotations instead of pixel-wise annotations, leading to a reduced workload during network training. AutoQC provides an automated solution for quantifying cardiac capillarization in basement-membrane-immunostained myocardial slices, eliminating the need for manual image analysis once it is trained.

Hasi Hays, Yue Yu, William Richardson

Cellular signaling networks represent complex information processing systems that have been modeled via traditional mathematical or statistical approaches. However, these methods often struggle to capture context-dependent signaling, pathway cross-talk, and temporal dynamics across multiple biological scales. Here, we introduce hierarchical molecular language models (HMLMs), a novel architecture that proposes a molecular network-specific large language model (LLM) to use in intracellular communication as a specialized molecular language, which includes molecules as tokens, protein interactions, post-translational modifications, and regulatory events modeled as semantic relationships within an adapted transformer architecture. HMLMs employ graph-structured attention mechanisms to accommodate signaling network topology while integrating information across the molecular, pathway, and cellular scales through hierarchical attention patterns. We demonstrate HMLM superiority using a cardiac fibroblast signaling network comprising over 100 molecular species across functional modules connected by regulatory edges. HMLM achieved a mean squared error (MSE) of 0.058 for temporal signaling predictions, representing 30% improvement over graph neural networks (GNNs: 0.083) and 52% improvement over ordinary differential equation models (ODEs: 0.121), with particular advantages under sparse temporal sampling conditions where HMLM maintained MSE = 0.041 with only 4 time-points. The HMLMs offer a foundation for AI-driven biology and medicine with predictable scaling characteristics suitable for interactive applications. By bridging molecular mechanisms with cellular phenotypes through AI-driven molecular language representation, HMLMs provide a powerful paradigm for systems biology that advances precision medicine applications and therapeutic discovery in the era of AI.

Jihong Wang, Chung-Hao Lee, William Richardson et al.

In this work, we present a novel approach to process the DIC measurements of multiple biaxial stretching protocols. In particular, we develop a optimization-based approach, which calculates the smoothed nodal displacements using a moving least-squares algorithm subject to positive strain constraints. As such, physically consistent displacement and strain fields are obtained. Then, we further deploy a data-driven workflow to heterogeneous material modeling from these physically consistent DIC measurements, by estimating a nonlocal constitutive law together with the material microstructure. To demonstrate the applicability of our approach, we apply it in learning a material model and fiber orientation field from DIC measurements of a porcine tricuspid valve anterior leaflet. Our results demonstrate that the proposed DIC data processing approach can significantly improve the accuracy of modeling biological materials.