Periodic Reporting for period 1 - Immuno-mechanics (ENGINEERING CELLULAR SELF‐ORGANISATION BY CONTROLLING THE IMMUNO-MECHANICAL INTERPLAY)
Berichtszeitraum: 2023-01-01 bis 2025-06-30
Scar formation after injuries can impair the full restoration of tissue function, while scar-free healing requires a well‐coordinated process of cellular self-organization. Our project addresses this challenge by studying how immune cells and the physical properties of their surrounding environment interact during the early stages of bone regeneration. When tissue is injured, cells contract and produce structural proteins like fibronectin and collagen, form new blood vessels, and set the stage for later tissue mineralization. However, if the early inflammation is not properly balanced and inflammation persists, scar formation will occur instead of complete healing.
By merging our expertise in osteo-immunology and mechanobiology, we have established a new cross-disciplinary field we call “Immuno-Mechanics.” In this project, we first identify the different mechanical niches – the unique physical conditions – that immune and stromal cells experience in both successful healing and how these differ in delayed or non healing. Understanding these niches is crucial to identify what hinders repair and eventually leads to scar forming tissues.
In the second phase, we aim at engineering synthetic niches that mimic the ones characteristic for sucessful and those for non-healing. By controlling how stromal and immune cells act in these custom-built settings, we gain fundamental understanding but also develop concepts to steer the processes. Thereby we engineer conditions that favor tissue regeneration following injury and allow to steer towards healthy regeneration instead of scarring.
In a third phase we verify that the identified principles can rescue healing even in compromised settings and allow to reprogram hematoma in living systems. By this approach we aim at idetifying principles we can translate into clinical routine to enable treatments of delayed or non-healing patients settings.
Overall, our project employes innovative biomaterial technolgies in a unique combination of biological and bioengineering approaches to unravel the immune-mechanical interactions during delayed healing to form the basis for novel therapies in a field of unmet need. Thereby our results will advance both the basic understanding on how mechanical forces and immune responses interact during regeneration and pave the way to empower targeted approaches to personalized therapy development to avoid scarring and improve recovery in patients at need.
By merging our expertise in osteo-immunology and mechanobiology, we have established a new cross-disciplinary field we call “Immuno-Mechanics.” In this project, we first identify the different mechanical niches – the unique physical conditions – that immune and stromal cells experience in both successful healing and how these differ in delayed or non healing. Understanding these niches is crucial to identify what hinders repair and eventually leads to scar forming tissues.
In the second phase, we aim at engineering synthetic niches that mimic the ones characteristic for sucessful and those for non-healing. By controlling how stromal and immune cells act in these custom-built settings, we gain fundamental understanding but also develop concepts to steer the processes. Thereby we engineer conditions that favor tissue regeneration following injury and allow to steer towards healthy regeneration instead of scarring.
In a third phase we verify that the identified principles can rescue healing even in compromised settings and allow to reprogram hematoma in living systems. By this approach we aim at idetifying principles we can translate into clinical routine to enable treatments of delayed or non-healing patients settings.
Overall, our project employes innovative biomaterial technolgies in a unique combination of biological and bioengineering approaches to unravel the immune-mechanical interactions during delayed healing to form the basis for novel therapies in a field of unmet need. Thereby our results will advance both the basic understanding on how mechanical forces and immune responses interact during regeneration and pave the way to empower targeted approaches to personalized therapy development to avoid scarring and improve recovery in patients at need.
First, our comprehensive in vivo study combining advanced animal model systems of immune-aging with scRNA seq represent a substantial step forward in unraveling the cellular self-organization in the complex and highly dynamics injured niche after bone fracture by providing detailed insights int spatial and temporal changes in immune and stromal cell compartments. Findings will lay the basis for developing immunomodulatory therapies for patients with impaired healing capacity due to dysregulated immune responses.
Furthermore, our integration of spatial transcriptomics across seven different organs has provided unprecedented insights into the dynamic gene expression programs that govern tissue repair. The identification of five distinct gene expression modules not only elucidates the molecular underpinnings of regeneration but also highlights critical differences between regenerative and fibrotic outcomes. From this analysis, three promising therapeutic targets have emerged, representing a major leap forward in our ability to modulate the healing process.
Another significant achievement is our novel MRI mapping technology developed for non-invasive characterization of ECM biophysical properties. This breakthrough method links quantitative MRI relaxation parameters to tissue elasticity, swelling, and stress relaxation, offering a new diagnostic tool for monitoring tissue alterations in regeneration and pathology. With pilot scans performed in clinical workflows on human subjects underscores its impact and translational potential. The study resulted in a publication in Nature Biomedical Engineering.
In vitro, our work with synthetic ECM-mimicking hydrogels has elucidated how mechanical cues, such as matrix viscoelasticity, guides macrophage polarization. This discovery is pivotal because it demonstrates a direct link between the mechanical properties of the tissue microenvironment and the immune response in a regenerating niche after injury, thereby opening new avenues for therapeutic intervention in bone healing and other regenerative processes.
Finally, the successful establishment of a longitudinal in vivo imaging system (LIMBostomy) marks a major milestone. This technology enables simultaneous monitoring of vessel formation and collagen deposition during the early phases of bone regeneration, thereby providing a powerful tool to assess the efficacy of pro-angiogenic and immunomodulatory therapies in real time.
Furthermore, our integration of spatial transcriptomics across seven different organs has provided unprecedented insights into the dynamic gene expression programs that govern tissue repair. The identification of five distinct gene expression modules not only elucidates the molecular underpinnings of regeneration but also highlights critical differences between regenerative and fibrotic outcomes. From this analysis, three promising therapeutic targets have emerged, representing a major leap forward in our ability to modulate the healing process.
Another significant achievement is our novel MRI mapping technology developed for non-invasive characterization of ECM biophysical properties. This breakthrough method links quantitative MRI relaxation parameters to tissue elasticity, swelling, and stress relaxation, offering a new diagnostic tool for monitoring tissue alterations in regeneration and pathology. With pilot scans performed in clinical workflows on human subjects underscores its impact and translational potential. The study resulted in a publication in Nature Biomedical Engineering.
In vitro, our work with synthetic ECM-mimicking hydrogels has elucidated how mechanical cues, such as matrix viscoelasticity, guides macrophage polarization. This discovery is pivotal because it demonstrates a direct link between the mechanical properties of the tissue microenvironment and the immune response in a regenerating niche after injury, thereby opening new avenues for therapeutic intervention in bone healing and other regenerative processes.
Finally, the successful establishment of a longitudinal in vivo imaging system (LIMBostomy) marks a major milestone. This technology enables simultaneous monitoring of vessel formation and collagen deposition during the early phases of bone regeneration, thereby providing a powerful tool to assess the efficacy of pro-angiogenic and immunomodulatory therapies in real time.
Foremost among these is the integration of spatial transcriptomics with advanced computational modeling to capture the dynamic interplay of gene expression in regenerating tissues. By analyzing data from seven different organs, we have not only uncovered conserved regenerative signatures but also identified failure points in non-regenerative conditions. This holistic approach offers a new state-of-the-art paradigm in understanding how tissue-specific contexts dictate regenerative outcomes (paper in preparation).
Another significant advance is the engineering of synthetic niches that accurately mimic the native ECM’s mechanical and osmotic properties. By harnessing biomaterials such as alginate hydrogels, we have demonstrated that subtle variations in matrix viscoelasticity can fundamentally alter immune cell behavior. This insight goes beyond conventional studies that often overlook the mechanobiology of cell niches or only consider 2D or predominantly elastic matrices with little resemblance of in vivo ECM material properties, positioning our work at the forefront of tissue engineering and immunomodulation.
Our MRI mapping technique is another breakthrough that advances the state-of-the-art in non-invasive tissue characterization. Unlike previous methods, our approach quantitatively correlates MRI parameters with specific biophysical properties of the ECM, which has the potential to enable clinicians to monitor tissue health and regeneration with unprecedented precision in the future (Kollert et al, Nat Biomed Engn, 2025).
The establishment of LIMBostomy for simultaneous imaging of vessel formation and collagen deposition in the healing tissue of an osteotomy in an in vivo mouse model represents another advance with great potential to acquire intriguing insights in the dynamics of cell and matrix organization at the onset of tissue regeneration (Rakhymzhan et al., iScience. 2024).
Collectively, these advancements are underpinned by a rigorous interdisciplinary approach that combines molecular biology, advanced imaging, computational modeling, and biomaterials science. The resulting innovations not only challenge the current understanding of tissue regeneration but also provide practical tools with great potential for clinical translation.
Another significant advance is the engineering of synthetic niches that accurately mimic the native ECM’s mechanical and osmotic properties. By harnessing biomaterials such as alginate hydrogels, we have demonstrated that subtle variations in matrix viscoelasticity can fundamentally alter immune cell behavior. This insight goes beyond conventional studies that often overlook the mechanobiology of cell niches or only consider 2D or predominantly elastic matrices with little resemblance of in vivo ECM material properties, positioning our work at the forefront of tissue engineering and immunomodulation.
Our MRI mapping technique is another breakthrough that advances the state-of-the-art in non-invasive tissue characterization. Unlike previous methods, our approach quantitatively correlates MRI parameters with specific biophysical properties of the ECM, which has the potential to enable clinicians to monitor tissue health and regeneration with unprecedented precision in the future (Kollert et al, Nat Biomed Engn, 2025).
The establishment of LIMBostomy for simultaneous imaging of vessel formation and collagen deposition in the healing tissue of an osteotomy in an in vivo mouse model represents another advance with great potential to acquire intriguing insights in the dynamics of cell and matrix organization at the onset of tissue regeneration (Rakhymzhan et al., iScience. 2024).
Collectively, these advancements are underpinned by a rigorous interdisciplinary approach that combines molecular biology, advanced imaging, computational modeling, and biomaterials science. The resulting innovations not only challenge the current understanding of tissue regeneration but also provide practical tools with great potential for clinical translation.