For example, the lipoprotein lipase [18], enhancer-binding protein ([21], collagen type X-alpha 1 (for 10?min at room heat, the pellets were resuspended in 3?mL CCM containing 1% antibiotic answer (GIBCO BRL, Gaithersburg, MD), plated in 6-well dishes at 3?mL/well, and incubated at 37C in a humidified atmosphere with 5% CO2. adipose tissue (A-MSCs) and cultured in normal conditions, in overconfluence or in inductive medium for osteogenic, adipogenic, or chondrogenic differentiation. Cultures were characterized for morphology, immunophenotype, and by quantitative real-time reverse transcriptionCpolymerase chain reaction for expression of pluripotency genes or markers of differentiation. Bone marrowCderived MSCs were also analyzed for comparison of these parameters. L-MSCs and A-MSCs exhibited the typical morphology, immunophenotype, and proliferation and differentiation pattern of MSCs. The analysis of gene expression showed a higher potential of adipose tissueCderived MSCs toward the osteogenic pathway and of lung-derived MSCs to chondrogenic differentiation, representing an important contribution for the definition of the type of cell to be used in clinical trials of cell therapy and tissue engineering. Introduction Mesenchymal stem cells (MSCs) were first described as bone marrow cells capable of originating fibroblast colonies (colony-forming unit-fibroblasts [CFU-Fs], [1]). The enumeration of CFU-Fs from new tissue samples has been considered indicative of the frequency of MSCs, but a direct relationship between the 2 has not been clearly established [2]. In 1985, a relationship between these cells and the bone marrow stroma was proposed by Owen [3], who proposed WZ4002 the presence of stromal stem cells that are able to self-renew and generate mature conjunctive/stromal cell types. The term MSCs was launched by Caplan in 1991 [4] and is currently utilized for stem cells with an intrinsic potential to give rise to different mesenchymal cell types such WZ4002 as osteoblasts, chondrocytes, adipocytes, tenocytes, as well as others. The Mesenchymal and Tissue Stem Cell Committee Rabbit polyclonal to HIRIP3 of the International Society for Cell Therapy has established the minimal criteria to define human MSCs: the capacity to proliferate as adherent cells, a defined surface phenotype (positive for CD105, CD73, and CD90, and unfavorable for CD45, CD34, CD14 or CD11b, CD79a or CD19, and HLA-DR), and the capacity to differentiate into osteoblasts, adipocytes, and chondroblasts [5]. Although conventionally isolated from your bone marrow, we as well as others have shown that MSCs are distributed throughout the whole organism, suggesting that they reside in association with blood vessels [6,7]. We have also suggested that this perivascular location of MSCs, associated to their amazing immunoregulatory capacity, implies a role in the maintenance of tissue homeostasis: in the case of tissue injury, MSCs secrete a panel of cytokines and factors that control the immune response to avoid an autoimmune process [8]. These studies have shown that, although similar in general WZ4002 characteristics, MSCs isolated from different tissues, such as brain, spleen, liver, kidney, lung, bone marrow, muscle mass, thymus, and pancreas, exhibit particular biological features, raising the question on whether they are identical cell populations or have important differences at the molecular level [9]. Cellular and molecular mechanisms underlying WZ4002 one of the fundamental properties of stem cells, self-renewal, have been the subject of many studies (examined in ref. [10]). While these studies provide an acceptable framework for defining MSCs at the molecular level, the presence of a large number of housekeeping genes prevents proper evaluation of their specific genetic message [11]. Gene expression analyses have shown that this differentiation of MSCs into mature cell types is usually controlled temporally, and that the regulation of the process entails the activity of transcription factors, growth factors, and signaling pathways (examined in ref. [12]). Transcription factors, such as Oct3/4 [13,14], Sox2 [15], and Nanog [16], maintain the pluripotency of embryonic stem cells, and may also be expressed in MSCs [17]. Other genes regulate the differentiation of stem cells into specific lineages. For example, the lipoprotein lipase [18], enhancer-binding protein ([21], collagen type X-alpha 1 (for 10?min at room heat, the pellets were resuspended in 3?mL CCM containing 1% antibiotic answer (GIBCO BRL, Gaithersburg, MD), plated in 6-well dishes at 3?mL/well, and incubated at 37C in a humidified atmosphere with 5% CO2. Nonadherent cells were removed.