Minhwa Park

Tonsil-derived Mesenchymal Stem Cells Ameliorate CCl4–induced Liver Fibrosis in Mice via Autophagy Activation

Liver transplantation is the treatment of choice for chronic liver failure, although it is complicated by donor shortage, surgery-related complications, and immunological rejection. Cell transplantation is an alternative, minimally invasive treatment option with potentially fewer complications. We used human palatine tonsil as a novel source of mesenchymal stem cells (T-MSCs) and examined their ability to differentiate into hepatocyte-like cells in vivo and in vitro. Carbon tetrachloride (CCl4) mouse model was used to investigate the ability of T-MSCs to home to the site of liver injury. T-MSCs were only detected in the damaged liver, suggesting that they are disease-responsive. Differentiation of T-MSCs into hepatocyte-like cells was confirmed in vitro as determined by expression of hepatocyte markers. Next, we showed resolution of liver fibrosis by T-MSCs via reduction of TGF-β expression and collagen deposition in the liver. We hypothesized that autophagy activation was a possible mechanism for T-MSC-mediated liver recovery. In this report, we demonstrate for the first time that T-MSCs can differentiate into hepatocyte-like cells and ameliorate liver fibrosis via autophagy activation and down-regulation of TGF-β. These findings suggest that T-MSCs could be used as a novel source for stem cell therapy targeting liver diseases.

Immune Suppressive Effects of Tonsil-Derived Mesenchymal Stem Cells on Mouse Bone-Marrow-Derived Dendritic Cells

Mesenchymal stem cells (MSCs) are considered valuable sources for cell therapy because of their immune regulatory function. Here, we investigated the effects of tonsil-derived MSCs (T-MSCs) on the differentiation, maturation, and function of dendritic cells (DCs). We examined the effect of T-MSCs on differentiation and maturation of bone-marrow- (BM-) derived monocytes into DCs and we found suppressive effect of T-MSCs on DCs via direct contact as well as soluble mediators. Moreover, T cell proliferation, normally increased in the presence of DCs, was inhibited by T-MSCs. Differentiation of CD4+ T cell subsets by the DC-T cell interaction also was inhibited by T-MSCs. The soluble mediators suppressed by T-MSCs were granulocyte-macrophage colony-stimulating factor (GM-CSF), RANTES, interleukin-6 (IL-6), and monocyte chemoattractant protein-1 (MCP-1). Taken together, T-MSCs exert immune modulatory function via suppression of the differentiation, maturation, and function of BM-derived DCs. Our data suggests that T-MSCs could be used as a novel source of stem cell therapy as immune modulators.

Mesenchymal stem cells ameliorate B-cell-mediated immune responses and increase IL-10-expressing regulatory B cells in an EBI3-dependent manner

Effector B cells are central contributors to the development of autoimmune disease by activating autoreactive T cells, producing pro-inflammatory cytokines and organizing ectopic lymphoid tissue. Conversely, IL-10-producing regulatory B (Breg) cells have pivotal roles in maintaining immunological tolerance and restraining excessive inflammation in autoinflammatory disease. Thus, regulating the equilibrium between antibody-producing effector B cells and Breg cells is critical for the treatment of autoimmune disease. In this study, we investigated the effect of human palatine tonsil-derived mesenchymal stem cells (T-MSCs) on estradiol (E2)-induced B-cell responses in vivo and in vitro. Transplantation of T-MSC into E2-treated mice alleviated B-cell-mediated immune responses and increased the population of IL-10-producing Breg cells. T-MSCs regulated the B-cell populations by producing Epstein–Barr virus (EBV)-induced 3 (EBI3), one of the two subunits of IL-35 that is the well-known inducer of Breg cells. We demonstrate a critical role of EBI3 (IL-35) in vitro by depleting EBI3 in T-MSCs and by adding exogenous IL-35 to the culture system. Taken together, our data suggest that IL-35-secreting MSCs may become an attractive therapeutic to treat B-cell-mediated autoimmune diseases via expanding Breg cells.

Tonsil-derived mesenchymal stromal cells produce CXCR2-binding chemokines and acquire follicular dendritic cell-like phenotypes under TLR3 stimulation

We previously isolated mesenchymal stromal cells from human tonsils (T-MSCs) and showed the potential of these cells to differentiate into the mesodermal lineage and acquire a follicular dendritic cell (FDC) phenotype under cytokine stimulation. Because these T-MSCs were originally isolated from inflamed tonsillar tissues, we were curious about their activation status in response to innate immune stimuli, such as Toll-like receptors (TLRs). Therefore, we analyzed the expression profile of TLRs in T-MSCs and stimulated the T-MSCs with TLR agonists. TLR3 stimuli induced C-C chemokine receptor type 6 expression in T-MSCs after 24h. Furthermore, results from cytokine arrays showed increases in epithelial neutrophil-activating peptide-78/C-X-C motif chemokine (CXCL) 5, granulocyte chemotactic protein-2/CXCL6, growth-related oncogene-α/CXCL1, interleukin-8/CXCL8, and interferon gamma-induced protein-10/CXCL10. CD54 expression was also increased after TLR3 stimulation. However, co-culturing T-MSCs with human B cells did not induce B-cell proliferation. This suggests that TLR3 stimulates the differentiation of T-MSCs into FDC-like cells and induces chemokine secretion, possibly by recruiting C-X-C chemokine receptor 2-expressing immune cells. In addition, T-MSCs also appeared to exert immunomodulatory effects by inhibiting B-cell proliferation, possibly by down-regulating CD18.

Characterization of wafer level package for mobile phone application

Hyundai Electronics has developed the wafer level chip size package, named Omega CSP, to provide the right package solution for mobile electronics products that require light weight, small size and low cost. The aim of this paper is to report both the electrical characteristics and the reliability of Omega CSP that has been used to assemble static random access memory (SRAM) device for cellular phone application. When compared to the current major package format, i.e., /spl mu/BGA, Omega CSP showed the similar electrical AC/DC characteristics. To certify package level reliability, temperature cycling (TC) test and pressure cooker test (PCT) were carried out. There was no crack or delamination after reliability test. In the temperature cycling test (-55/spl deg/C to 125/spl deg/C) at board level, Omega CSP with 325 /spl mu/m or 425 /spl mu/m solder ball pad passed 1000 cycles. In addition to temperature cycling test, mechanical shock test, variable frequency vibration test and four point twisting test at board level were also evaluated. Considering the lower cost as well as the smaller form factor of real chip size than current package, Omega CSP has a high potential to be applied into mobile electronics product.

RNA sequencing reveals a transcriptomic portrait of human mesenchymal stem cells from bone marrow, adipose tissue, and palatine tonsils

Human mesenchymal stem cells (MSCs) are adult multipotent cells that have plasticity and inhabit the stroma of diverse tissues. The potential utility of MSCs has been heavily investigated in the fields of regenerative medicine and cell therapy. However, MSCs represent diverse populations that may depend on the tissue of origin. Thus, the ability to identify specific MSC populations has remained difficult. Using RNA sequencing, we analyzed the whole transcriptomes of bone marrow-derived MSCs (BMs), adipose tissue-derived MSCs (AMs), and tonsil-derived MSCs (TMs). We categorized highly regulated genes from these MSC groups according to functional gene ontology (GO) classification. AMs and TMs showed higher expression of genes encoding proteins that function in protein binding, growth factor, or cytokine activity in extracellular compartments than BMs. Interestingly, TM were highly enriched for genes coding extracellular, protein-binding proteins compared with AMs. Functional Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis also showed differentially enriched signaling pathways between the three MSC groups. Further, we confirmed surface antigens expressed in common and in a tissue-specific manner on BMs, AMs, and TMs by flow cytometry analysis. This study provides comprehensive characteristics of MSCs derived from different tissues to better understand their cellular and molecular biology.

Tonsil-Derived Mesenchymal Stem Cells Promote Bone Mineralization and Reduce Marrow and Visceral Adiposity in a Mouse Model of Senile Osteoporosis.

Osteoporosis is a disease that affects 35% women and 20% men aged more than 65 years. Reduction in bone formation and increased bone resorption are known factors that drive osteoporosis, but recent studies suggest a positive correlation between bone marrow adipose tissue (MAT) and osteoporosis. Previously, we have observed that tonsil-derived mesenchymal stem cells (T-MSCs) reduce MAT in a mouse model of bone marrow depletion. That prompted us to investigate on the senile osteoporosis to characterize the bone-forming effect, as well as MAT-reducing effect of T-MSCs. In a mouse model of senescence-accelerated mouse prone 6 (SAMP6), we injected T-MSCs or T-MSC conditioned medium (CM) through tail vein and examined changes in bone microstructure using micro-CT scan and hematoxylin & eosin (H&E) staining. Biochemical markers of osteoporosis, deoxypyridinoline (DPD) and osteocalcin, were examined by ELISA. Results demonstrated attenuation in the progression of osteoporosis, in part, by sustaining osteocalcin production and by blocking MAT accumulation. Increase in matrix mineralization was determined using in vitro culture of murine preosteoblast cell line by treatment of T-MSC CM. Interestingly, T-MSC CM induced continuous weight loss and selectively reduced visceral adipose tissue mass. Finally, antiadipogenic effects of T-MSC CM were determined in vitro. In conclusion, regulation of bone together with MAT could be considered as a new therapeutic option for the treatment of senile osteoporosis and this report may provide a framework for future cell therapy using T-MSCs.

Tonsil‐derived mesenchymal stem cells (T‐MSCs) prevent Th17‐mediated autoimmune response via regulation of the programmed death‐1/programmed death ligand‐1 (PD‐1/PD‐L1) pathway

Our knowledge of the immunomodulatory role of mesenchymal stem cells (MSCs) in both the innate and adaptive immune systems has dramatically expanded, providing great promise for treating various autoimmune diseases. However, the contribution of MSCs to Th17‐dominant immune disease, such as psoriasis and its underlying mechanism remains elusive. In this study, we demonstrated that human palatine tonsil‐derived MSCs (T‐MSCs) constitutively express both the membrane‐bound and soluble forms of programmed death‐ligand 1 (PD‐L1), which enables T‐MSCs to be distinguished from MSCs originating from other organs (i.e. bone marrow or adipose tissue). We also found that T‐MSC‐derived PD‐L1 effectively represses Th17 differentiation via both cell‐to‐cell contact and a paracrine effect. Further, T‐MSCs increase programmed death‐1 (PD‐1) expression on T‐cells by secreting IFN‐β, which may enhance engagement with PD‐L1. Finally, transplantation of T‐MSCs into imiquimod‐induced psoriatic skin inflammation in mice significantly abrogated disease symptoms, mainly by blunting the Th17 response in a PD‐L1‐dependent manner. This study suggests that T‐MSCs might be a promising cell source to treat autoimmune diseases such as psoriasis, via its unique immunoregulatory features. Copyright

Mesenchymal stem cells inhibit RANK-RANKL interactions between osteoclasts and Th17 cells via osteoprotegerin activity

Th17 cells play a critical role in several autoimmune diseases, including psoriasis and psoriatic arthritis (PsA). Psoriasis is a chronic inflammatory skin disease associated with systemic inflammation and comorbidities, such as PsA. PsA develops in nearly 70% of patients with psoriasis, and osteoclasts associated bone erosion is a hallmark of the disease. Thus far, the effect of Th17 cells on osteoclastogenesis via direct cell-to-cell interactions is less understood. In this study, we observed that Th17 cells directly promote osteoclast differentiation and maturation via expression of receptor activator of nuclear factor-κ β ligand (RANKL) in vitro. We investigated the impact of conditioned medium obtained from human palatine tonsil-derived mesenchymal stem cells (T-CM) on the interactions between osteoclasts and Th17 cells. T-CM effectively blunted the RANK-RANKL interaction between the osteoclast precursor cell line RAW 264.7 and Th17 cells via osteoprotegerin (OPG) activity. The frequency of tartrate-resistant acid phosphatase (TRAP)-positive cells in the bone marrow of an imiquimod (IMQ)-induced psoriasis mouse model was decreased following T-CM injection. Therefore, our data provide novel insight into the therapeutic potential of tonsil-derived mesenchymal stem cell-mediated therapy (via OPG production) for the treatment of pathophysiologic processes induced by osteoclasts under chronic inflammatory conditions such as psoriasis.

Conditioned media from human palatine tonsil mesenchymal stem cells regulates the interaction between myotubes and fibroblasts by IL-1Ra activity

Saturated free fatty acids (FFAs) act as lipid mediators and induce insulin resistance in skeletal muscle. Specifically, in obesity‐related diseases such as type 2 diabetes, FFAs directly reduce insulin sensitivity and glucose uptake in skeletal muscle. However, the knowledge of how FFAs mediate inflammation and subsequent tissue disorders, including fibrosis in skeletal muscle, is limited. FFAs are a natural ligand for toll‐like receptor 2 (TLR2) and TLR4, and induce chronic low‐grade inflammation that directly stimulates skeletal muscle tissue. However, persistent inflammatory stimulation in tissues could induce pro‐fibrogenic processes that ultimately lead to perturbation of the tissue architecture and dysfunction. Therefore, blocking the link between inflammatory primed skeletal muscle tissue and connective tissue might be an efficient therapeutic option for treating obesity‐induced muscle inactivity. In this study, we investigated the impact of conditioned medium obtained from human palatine tonsil‐derived mesenchymal stem cells (T‐MSCs) on the interaction between skeletal muscle cells stimulated with palmitic acid (PA) and fibroblasts. We found that PA‐treated skeletal muscle cells actively secreted interleukin‐1β (IL‐1β) and augmented the migration, proliferation and expression of fibronectin in L929 fibroblasts. Furthermore, T‐CM inhibited the skeletal muscle cell‐derived pro‐fibrogenic effect via the production of the interleukin‐1 receptor antagonist (IL‐1Ra), which is an inhibitor of IL‐1 signalling. Taken together, our data provide novel insights into the therapeutic potential of T‐MSC‐mediated therapy for the treatment of pathophysiological processes that occur in skeletal muscle tissues under chronic inflammatory conditions.