Human Bone Marrow Contains Mesenchymal Stromal Stem Cells That Differentiate In Vitro into Contractile Myofibroblasts Controlling T Lymphocyte Proliferation

Abstract

Mesenchymal stromal stem cells (MSC) that reside in the bone marrow (BM) can be amplified in vitro. In 2-dimension (D) cultures, MSC exhibit a morphology similar to fibroblasts, are able to inhibit T lymphocyte and natural killer cell proliferation, and can be differentiated into adipocytes, chondrocytes, or osteoblasts if exposed to specific media. Here we show that medullar MSC cultured in 2D formed an adherent stroma of cells expressing well-organized microfilaments containing α-smooth muscle actin and nonmuscle myosin heavy chain IIA. MSC could be grown in 3D in collagen membranes generating a structure which, upon exposition to 50 mM KCl or to an alternating electric current, developed a contractile strength that averaged 34 and 45 μN/mm2, respectively. Such mechanical tension was similar in intensity and in duration to that of human placenta and was annihilated by isosorbide dinitrate or 2,3-butanedione monoxime. Membranes devoid of MSC did not exhibit a significant contractility. Moreover, MSC nested in collagen membranes were able to control T lymphocyte proliferation, and differentiated into adipocytes, chondrocytes, or osteoblasts. Our observations show that BM-derived MSC cultured in collagen membranes spontaneously differentiate into contractile myofibroblasts exhibiting unexpected properties in terms of cell differentiation potential and of immunomodulatory function.

Statistical Mechanics of Non-Muscle Myosin IIA in Human Bone Marrow-Derived Mesenchymal Stromal Cells Seeded in a Collagen Scaffold: A Thermodynamic Near-Equilibrium Linear System Modified by the Tripeptide Arg-Gly-Asp (RGD)

“…MSC extraction, amplification, seeding in 3D-solid collagen scaffolds and basic contraction characteristics have been previously described [27,28]. The present experiments were performed with the same type of MSC-laden collagen scaffolds used in a previous study [10]. Scaffolds consisted in clinical hemostatic sponges (Avitene™ ultrafoam collagen, ref.…”

“…Numerous myofibroblasts are present in pathological tissues, such as cancer stroma, and in fibrotic processes [7][8][9]. Finally, considering bioengineered tissues, human medullar MSCs seeded into collagen scaffolds display contractile features, similar to those of the human placenta [10]. Myofibroblast contractility is empowered by the molecular motor NMMIIA [11,12].…”

Tripeptide Arg-Gly-Asp (RGD) modifies the molecular mechanical properties of the non-muscle myosin IIA in human bone marrow-derived myofibroblasts seeded in a collagen scaffold

“…The human femoral heads were collected during surgical interventions for hip replacements, according to the CCER, and after patients were informed and gave their written consent. MSC extraction, amplification and MSC seeding in 3D-solid collagen scaffolds have been previously described in detail [1]. Thus, BM-derived MSCs seeded in collagen scaffolds have been shown to form an adherent cell stroma with well-organized microfilaments expressing α-SMA and a high level of NMMIIA, but they are devoid of muscle myosin.…”

“…Recently, we reported that mesenchymal stem cells (MSCs) derived from human bone marrow (BM) and seeded in solid 3D-collagen scaffolds differentiated into myofibroblasts in the presence of human platelet lysate (HPL) and contracted when exposed to KCl or an electrical field [1]. Myofibroblasts in collagen scaffolds were shown to contain α-smooth muscle actin (α-SMA) and non-muscle myosin II (NMMIIA), which were colocalized, but no muscle myosin.…”

“…The molecular motor of myofibroblasts is the NMMIIA [20, 21]. NMMIIA, whose kinetics are considerably slower than those of type II muscle myosin (MMII) [19, 22], has been found to be the molecular motor driving the contraction in both human placenta [20] and MSC-seeded collagen scaffolds [1].…”