Multilineage-differentiating stress-enduring (Muse)-like cells exist in synovial tissue

Abstract

IntroductionCartilage regeneration is a promising therapy for restoring joint function in patients with cartilage defects. The limited availability of autologous chondrocytes or chondrogenic progenitor cells is an obstacle to its clinical application. We investigated the existence and chondrogenic potential of synovial membrane-derived multilineage-differentiating stress-enduring (Muse)-like cells as an alternative cell source for cartilage regeneration.MethodsCells positive for stage-specific embryonic antigen-3 (SSEA-3), a marker of Muse cells, were isolated from the synovial membranes of 6 of 8 patients (median age, 53.5 years; range 36–72 years) by fluorescence-activated cell sorting. SSEA-3-positive cells were cultured in methylcellulose to examine their ability to form Muse clusters that are similar to the embryoid bodies formed by human embryonic stem cells. Muse clusters were expanded and chondrogenic potential of M-cluster-derived MSCs examined using a pellet culture system. Chondrogenic differentiation was evaluated by proteoglycan, safranin O, toluidine blue and type II collagen staining. To evaluate the practicality of the procedure for isolating Muse-like cells, we compared chondrogenic potential of M-cluster derived MSCs with expanded cells derived from the clusters formed by unsorted synovial cells.ResultsSynovial membranes contained SSEA-3-positive cells that after isolation exhibited Muse-like characteristics such as forming clusters that expressed NANOG, OCT3/4, and SOX2. In the pellet culture system, cell pellets created from the M-cluster-derived MSCs exhibited an increase in wet weight, which implied an increase in extracellular matrix production, displayed metachromasia with toluidine blue and safranin O staining and were aggrecan-positive and type II collagen-positive by immunostaining. Unsorted synovial cells also formed clusters in methylcellulose culture, and the expanded cell population derived from them exhibited chondrogenic potential. The histological and immunohistochemical appearance of chondrogenic pellet created from unsorted synovial cell-derived cells were comparable with that from M-cluster-derived MSCs.ConclusionsMuse-like cells can be isolated from the human synovial membrane, even from older patients, and therefore may provide a source of multipotent cells for regenerative medicine. In addition, the cluster-forming cell population within synovial cells also has excellent chondrogenic potential. These cells may provide a more practical option for cartilage regeneration.

Evaluation of the Effects of Synovial Multipotent Cells on Deep Digital Flexor Tendon Repair in a Large Animal Model of Intra‐Synovial Tendinopathy

“…While cell‐surface marker expression showed consistent high expression for two robust MSC markers, CD29 and CD44, there was a wide range in expression for CD73, CD90, CD166, and MHC‐I. CD105 was expressed at lower levels compared with our observations with ovine bone marrow MSCs, and an absence of CD271 expression, which is consistent with reports in normal human joint synovium . While the hematopoietic marker CD34 was absent, there was variable expression of CD45 and MHC‐II, indicating potential inclusion of leukocytic cells from perivascular tissue.…”

“…CD105 was expressed at lower levels compared with our observations with ovine bone marrow MSCs, 13,14 and an absence of CD271 expression, which is consistent with reports in normal human joint synovium. 21,23,24 While the hematopoietic marker CD34 was absent, there was variable expression of CD45 and MHC-II, indicating potential inclusion of leukocytic cells from perivascular tissue. However, these profiles are not dissimilar to recent studies of synovial MSCs derived from inflammed human knee joints.…”

Intraarticular Ligament Degeneration Is Interrelated with Cartilage and Bone Destruction in Osteoarthritis

“…Gene expression associated with cytoskeleton and protein dephosphorylation, but also other pathways could be distinguished in ACL-MSCs from young and old donors [68]. The Hoffa’s fat pad and the synovial membrane covering the ACL are also known to contain stem cells [69,70]. Stem cells of the Hoffa’s fat pad change their expression pattern in OA [71].…”

“…Stem cells of the Hoffa’s fat pad change their expression pattern in OA [71]. In the synovial membrane, some Muse-like (stress enduring cluster forming multipotent) stem cells have been detected with strong chondrogenic potential expressing markers of Muse cells such as stage-specific antigen (SSEA)-3 and CD105 as well as pluripotency markers such as Nanog, octamer binding proteins (Oct) 3,4, and sex determining region Y-box 2 (Sox2) [70]. Taken together, the ACL contains different stem cell niches harboring heterogeneous stem cell populations.…”

Muse cells and Neurorestoratology

“…But the bone marrow is directly connected to the peripheral blood, so Muse cells in blood should be from the bone marrow. Moreover, Muse cells also distribute to the connective tissue of every organ, which has been demonstrated in the dermis, spleen, pancreas, trachea, umbilical cord, adipose tissue, and synovial membrane, but the percentage is as sparse as 0.01%-3% [5,28,29]. Muse cells are even found in the pia mater and arachnoid of the brain (unpublished data by Mari Dezawa [30]).…”