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Ameer-Beg, S.

Publications and source records attributed to Ameer-Beg, S..

3 recordsLinked to original sources

VISIBLE: An imaging-driven system for sampling, biofabrication, and manipulation of complex biological models

Complex in vitro models (CIVMs), including organoids, spheroids, and bioprinted constructs, have emerged as powerful platforms for recapitulating human tissue architecture and function. However, their inherent heterogeneity and dynamic nature pose significant challenges for standardization, reproducibility, and real-time manipulation. Here, we present VISIBLE (Versatile Imaging-Based Interactive Sampling and Bioprinting System), a modular, imaging-guided platform that integrates real-time monitoring with automated manipulation and 3D bioprinting that addresses these challenges. VISIBLE employs a dual-axis system comprising independently controlled tool-heads and microscope stages, enabling precise spatiotemporal interventions within live cultures. We demonstrate the system capabilities across a range of applications, including morphology- and function-based sampling of organoids and neurospheres, interactive 3D bioprinting, serial scratch assays, and real-time cell-cell interaction studies. Furthermore, we illustrate the system utility in translational contexts through the selective sampling and implantation of patient-derived xenograft organoids. VISIBLE supports long-term culture within an integrated incubation environment and accommodates interchangeable tool-heads for scalable, high-throughput workflows. By enabling closed-loop, feedback-controlled experimentation, VISIBLE addresses some of the critical limitations in existing CIVM platforms and offers a new versatile solution for a wide range of biomedical research applications. This work represents a significant step toward the development of autonomous experimental systems for complex tissue modelling and preclinical investigation.

bioengineering↗

NHSL3 interacts with Ena/VASP proteins and the Scar/WAVE complex and promotes cell migration.

Tight control of mesenchymal cell migration is important for embryonic development and its deregulation causes disease. It is driven by lamellipodia protrusion, the leading edge of the migrating cell. This is controlled by Rac-Scar/WAVE-Arp2/3 complexes driving actin filament nucleation coupled to Ena/VASP proteins mediating actin filament elongation. These activities are coordinated by leading-edge proteins, such as Lamellipodin and NHSL1. Here, we discovered KIAA1522/NHSL3 as an additional regulator of these essential actin effectors. We reveal that NHSL3 promotes cell migration. NHSL3 co-localises at the edge of lamellipodia with Ena/VASP proteins and the Scar/WAVE complex. We show that it binds to Ena/VASP proteins and the Scar/WAVE complex and functions to inhibit Scar/WAVE-Arp2/3 activity in cells. NHSL3 interacts with the Scar/WAVE complex subunit Abi and, in contrast to other known Scar/WAVE complex binders, additionally to the CYFIP1/2 subunit through 3 short linear motifs. Thus, control of actin filament nucleation and elongation at the leading edge of mesenchymal cells is more complex than anticipated. Our study provides insights into the intricate regulation of lamellipodial actin networks highly relevant for understanding control of mesenchymal cell migration during development and diseases.

cell biology↗

Cardiomyocyte mechanical memory is regulated through the talin interactome and DLC1 dependent regulation of RhoA

Mechanical properties are cues for many biological processes in health or disease. Likewise, in the heart it is becoming clearer that mechanical signals are critically involved in the disease progression. Cardiomyocytes sense the mechanical properties of their environment at costameres through integrins and associated proteins, including the mechanosensitive protein talin as an integral component. Our previous work indicated different modes of talin tension, depending on the extracellular matrix stiffness. Here, we wanted to study how this leads to downstream mechanotransduction changes, further influencing the cardiomyocyte phenotype. Combining immunoprecipitations and Fluorescence Recovery after Photobleaching (FRAP) experiments, we identify that the talin interacting proteins DLC1, RIAM and paxillin each preferentially bind to talin at specific extracellular matrix stiffness and this interaction is preserved even in absence of tension. This demonstrates a mechanical memory, which we confirm further in vivo in mouse hearts. The mechanical memory is regulated through adhesion related kinase pathways. Optogenetic experiments using the LOVTRAP systems confirm direct competition between the individual proteins, which again is altered through phosphorylation. DLC1 regulates RhoA activity in a stiffness dependent way and both loss and overexpression of DLC1 results in myofibrillar disarray. Together the study demonstrates a mechanism of imprinting mechanical information into the talin-interactome to finetune RhoA activity, with impacts on cardiac health and disease.

cell biology↗