Multicellular spheroids of bone marrow stromal cells: a three-dimensional in vitro culture system for the study of hematopoietic cell migration

Abstract

Cell fate decisions are governed by a complex interplay between cellautonomous signals and stimuli from the surrounding tissue. In vivo cells are connected to their neighbors and to the extracellular matrix forming a complex three-dimensional (3-D) microenvironment that is not reproduced in conventional in vitro systems. A large body of evidence indicates that mechanical tension applied to the cytoskeleton controls cell proliferation, differentiation and migration, suggesting that 3-D in vitro culture systems that mimic the in vivo situation would reveal biological subtleties. In hematopoietic tissues, the microenvironment plays a crucial role in stem and progenitor cell survival, differentiation, proliferation, and migration. In adults, hematopoiesis takes place inside the bone marrow cavity where hematopoietic cells are intimately associated with a specialized three 3-D scaffold of stromal cell surfaces and extracellular matrix that comprise specific niches. The relationship between hematopoietic cells and their niches is highly dynamic. Under steady-state conditions, hematopoietic cells migrate within the marrow cavity and circulate in the bloodstream. The mechanisms underlying hematopoietic stem/progenitor cell homing and mobilization have been studied in animal models, since conventional two-dimensional (2-D) bone marrow cell cultures do not reproduce the complex 3-D environment. In this review, we will highlight some of the mechanisms controlling hematopoietic cell migration and 3-D culture systems.

T Cell-, Interleukin-12-, and Gamma Interferon-Driven Viral Clearance in Measles Virus-Infected Brain Tissue

“…The shortcomings of an in vivo study can be overcome by working in three-dimensional tissue explants populated with resident cell types in their native microenvironment. Studies of hostpathogen interactions, cellular interactions within complex organs, cell migration, and regeneration have all benefited by advancing from a two-dimensional cell monolayer to threedimensional tissue systems (1,48,52,66,86). Virus infection of cultured murine brain explants provides a means to investigate the migration of immune cells to infected neurons in an intacttissue model.…”

Long term morphological characterization of mesenchymal stromal cells 3D spheroids built with a rapid method based on entry-level equipment

“…Thanks to the short time required for generation, the spheroids obtained are characterized by the absence of a necrotic core, whereas it is present in the spheroids generated with most of the other systems (Wartenberg and Acker 1995), this causing an overall response heterogeneity and low proliferation rate of the composing cells (Occhetta et al 2015). Furthermore, the pellet culture method is the most known generation method that allows tuning the size of the obtained spheroid by simply controlling the number of cells seeded in the tubes (Rossi et al 2005), although there is not a validated protocol to obtain the spheroids, and typically the researchers adopt their own modified version (Zhang et al 2010) of the original method outlined by Johnstone et al Nonetheless, the pellet culture method is the perfect solution for researchers that want rapidly producing large, spherical-shaped MSC spheroids, of a desired size, without high costs and needs of specialized equipment.…”

Restoring the cardiac contractile function using implants with neural bundles in the sinoatrial node of the heart in dilated cardiomyopathy at dogs.

“…They mimic the biological situation in vivo when incorporated in a three-dimensional environment 40 , they develop upper-order intercellular structures facilitating proliferation, differentiation and angiogenesis 15 . The cardiospheres extended as adherent monolayer 15 were transplanted to mice with severe induced immunodeficiency in the pre-infarcted area 41 . The replacement of the necrotic tissue with neoformation myocardiocytes and the functional improvement of the myocardium occurred within 18-20 days 15 .…”