🐣Developmental Biology Unit 7 – Cell Migration and Morphogenesis
Cell migration and morphogenesis are crucial processes in developmental biology. They involve the movement of cells and the shaping of tissues, playing key roles in gastrulation, organ formation, and wound healing. These processes rely on complex interactions between cells and their environment.
Understanding cell migration and morphogenesis requires knowledge of cellular mechanisms, molecular players, and signaling pathways. Key concepts include cell polarity, cytoskeletal dynamics, and extracellular matrix interactions. Techniques like live cell imaging and in vitro assays help researchers study these fascinating biological phenomena.
Heparan sulfate proteoglycans (HSPGs) bind growth factors and regulate their availability and signaling
Hyaluronan a glycosaminoglycan that influences cell migration and tissue hydration
Durotaxis the directed movement of cells towards regions of higher substrate stiffness
Contact guidance the alignment and migration of cells along ECM fibers or topographical features
Developmental Contexts and Examples
Gastrulation the formation of the three germ layers (ectoderm, mesoderm, endoderm) through coordinated cell movements (invagination, involution, epiboly)
Neural crest migration a highly migratory population of cells that give rise to various cell types (neurons, glia, melanocytes, craniofacial structures)
Angiogenesis the formation of new blood vessels from pre-existing ones, involves endothelial cell migration and tube formation
Wound healing the coordinated migration of keratinocytes, fibroblasts, and immune cells to close a wound and restore tissue integrity
Drosophila border cell migration a model system for studying collective cell migration during oogenesis
Zebrafish lateral line development involves the collective migration of a group of cells called the primordium
Xenopus convergent extension the narrowing and lengthening of the body axis during gastrulation, driven by polarized cell intercalation
Chick primitive streak formation the site of gastrulation in avian embryos, where epiblast cells undergo EMT and migrate to form the mesoderm and endoderm
Techniques for Studying Cell Migration
Live cell imaging allows the visualization of cell migration in real-time using fluorescent reporters and microscopy techniques (confocal, light sheet)
Cell tracking software enables the quantification of cell migration speed, directionality, and trajectory
In vitro assays (wound healing, transwell, microfluidic devices) provide controlled environments to study cell migration under specific conditions
In vivo lineage tracing using genetic labeling techniques (Cre-loxP, fluorescent proteins) to follow the fate and migration of specific cell populations
Optogenetics the use of light-sensitive proteins to control cell behavior and signaling pathways with spatial and temporal precision
Biomaterial scaffolds engineered matrices that mimic the physical and biochemical properties of the ECM to study cell migration in 3D environments
Traction force microscopy a technique that measures the forces exerted by migrating cells on their substrate
Atomic force microscopy (AFM) a high-resolution imaging technique that can also measure the mechanical properties of cells and tissues
Morphogenesis and Tissue Formation
Convergent extension a conserved morphogenetic process that elongates tissues through polarized cell intercalation
Branching morphogenesis the formation of branched structures (lungs, mammary glands, kidneys) through coordinated cell migration and proliferation
Epithelial folding the bending and invagination of epithelial sheets to create complex 3D structures (neural tube, optic cup)
Cell sorting the segregation of different cell types based on their differential adhesion properties
Planar cell polarity (PCP) the coordinated orientation of cells within the plane of an epithelium, essential for directed cell migration and tissue organization
Mechanically-driven morphogenesis the shaping of tissues through the generation and transmission of mechanical forces (tension, compression)
Tissue fusion the merging of two separate tissue layers or structures to form a continuous unit (palate, heart)
Organoids self-organizing 3D cell cultures that recapitulate the structure and function of mini-organs, useful for studying morphogenesis and disease modeling
Clinical Implications and Future Directions
Cancer metastasis the spread of cancer cells from the primary tumor to distant sites, involves cell migration and invasion
Targeting cell migration pathways (Rho GTPases, FAK, MMPs) is a promising strategy for anti-metastatic therapies
Wound healing disorders (chronic wounds, fibrosis) result from impaired cell migration and tissue repair
Regenerative medicine harnessing the migratory and morphogenetic potential of stem cells to regenerate damaged or lost tissues
Organ-on-a-chip microfluidic devices that mimic the structure and function of human organs, enabling the study of cell migration and drug screening
Single-cell sequencing technologies provide high-resolution insights into the molecular heterogeneity of migrating cell populations
Computational modeling integration of experimental data with mathematical models to predict and simulate cell migration and morphogenesis
Biomaterials and tissue engineering designing synthetic matrices and scaffolds that guide cell migration and tissue formation for regenerative applications
Gene editing (CRISPR-Cas9) a powerful tool for dissecting the genetic basis of cell migration and morphogenesis, and for developing targeted therapies