Toll-Like Receptor 7 (TLR7) Mediated Transcriptomic Changes on Human Mast Cells.

BACKGROUND: Mast cells are skin immune sentinels located in the upper dermis, where wheal formation and sensory nerve stimulation take place. Skin inflammation is occasionally accompanied by mast cell-driven responses with wheals, angioedema, or both. Immunoglobulin E (IgE) antibodies are regarded as typical stimuli to drive mast cell activation. However, various causative factors, including microbial infections, can drive IgE-independent mast cell response. When infected, the innate immunity orchestrates an immune response by activating receptor signaling via Toll-like receptors (TLRs). OBJECTIVE: In this study, we determined the effect of TLR7 stimulation on mast cells to investigate the possible mechanism of IgE-independent inflammatory response. METHODS: Human mast cell (HMC) line, HMC-1 cells were treated with TLR7 agonist and the morphologic alteration was observed in transmission electron microscopy. Further, TLR7 agonist treated HMC-1 cells were conducted to RNA sequencing to compare transcriptomic features. RESULTS: HMC-1 cells treated with TLR7 agonist reveals increase of intracellular vesicles, lipid droplets, and ribosomes. Also, genes involved in pro-inflammatory responses such as angiogenesis are highly expressed, and Il12rb2 was the most highly upregulated gene. CONCLUSION: Our data suggest that TLR7 signaling on mast cells might be a potential therapeutic target for mast cell-driven, IgE-independent skin inflammation.

Multidisciplinary aerodigestive program at a children's hospital: A protocol for a prospective observational study.

BACKGROUND: Children with complex chronic multisystemic diseases frequently require care from multiple pediatric subspecialists. The aerodigestive program is a multidisciplinary program that diagnoses and treats pediatric patients with complex multi-systematic problems affecting airway, breathing, feeding, swallowing, or growth. The aim of this study is to present the protocol of the aerodigestive program of a children's hospital. METHODS AND DESIGN: This study is a prospective study to evaluate and compare the overall improvement of patients' objective and subjective conditions before and after the AeroDigestive Team (ADT) program. Among children from 1 month to 18 years of age, patients with complex problems of the airway, breathing, feeding, swallowing, or growth meeting at least two parameters of the inclusion criteria were enrolled. The overall process included referral based on the inclusion criteria, enrollment of ADT program with informed consents, interview and questionnaire for assessing patients' medical condition, prescheduling appointment, multi-specialists' evaluation, monthly team meetings, wrap-up discussion with the patients and family, therapeutic intervention, and follow-up at 6 months with the assessment of outcome measures. The outcome was evaluated objectively and subjectively. The objective outcome measure was divided into surgical or medical intervention, assessment of changes in medical condition, and follow-up study. Both caregiver interviews and questionnaires using a scoring system were used as subjective outcome measures before and after the ADT program. Children were scheduled to be followed-up at 6 months after the interventions or ADT meeting. DISCUSSION: The aerodigestive program is expected to provide comprehensive and multidisciplinary management of children with complex airway and digestive tract disorders.

Development of a Multidisciplinary Aerodigestive Program: An Institutional Experience.

We share our experience on the implementation of a multidisciplinary aerodigestive program comprising an aerodigestive team (ADT) so as to evaluate its feasibility. We performed a retrospective chart review of the patients discussed at the monthly ADT meetings and analyzed the data. A total of 98 children were referred to the ADT during the study period. The number of cases increased steadily from 3.5 cases per month in 2019 to 8.5 cases per month in 2020. The median age of patients was 34.5 months, and 55% were male. Among the chronic comorbidities, neurologic disease was the most common (85%), followed by respiratory (36%) and cardiac (13%) disorders. The common reasons for consultation were suspected aspiration (56%), respiratory difficulty (44%), drooling/stertor (30%), regurgitation/vomiting (18%), and feeding/swallowing difficulty (17%). Following discussions, 58 patients received active interventions, including fundoplication, gastrostomy, laryngomicrosurgery, tracheostomy, and primary dilatation of the airway. According to the questionnaire of the caregiver, the majority agreed that the main symptoms and quality of life of patients had improved (88%), reducing the burden on caregivers (77%). Aerodigestive programs may provide comprehensive and multidisciplinary management for children with complex airway and digestive tract disorders.

Comparing Axillary and Rectal Temperature Measurements in Very Preterm Infants: A Prospective Observational Study.

PURPOSE: The agreement between axillary temperature (AT) and rectal temperature (RT) measurements has not been well established in preterm infants. Therefore, our study aimed to evaluate the agreement between AT and RT measurements in very preterm infants. METHODS: Preterm infants <32 weeks of gestational age were prospectively included. The infants' body temperature (BT) was measured twice a day from day 1 to day 6. A paired t-test and the Bland-Altman method were used to analyze the difference between the AT and RT. A linear regression model was used to explore the effects of environmental factors on the differences of BT between the axillary and rectal measurements and to calibrate the RT according to the AT. RESULTS: Eighty infants each underwent 6 paired axillary and rectal measurements. The gestational age varied from 22 to 31 weeks (mean 28 weeks). The birth weight varied from 302 to 1,770 g (mean 1,025 g). The AT was significantly lower than the RT. The difference between the RT and AT significantly increased with increasing RT. The AT and RT demonstrated poor agreement overall; however, the RT can be estimated using the AT with the following equation: RT = -4.033 + 1.116 × AT. Environmental factors, including the incubator temperature, incubator humidity, phototherapy, and application of invasive mechanical ventilation did not affect the differences between the AT and RT measurements. CONCLUSION: AT measurements cannot be interchangeably used with RT measurements in very preterm infants.

Verification of the role of exosomal microRNA in colorectal tumorigenesis using human colorectal cancer cell lines.

Exosomes are a group of small membranous vesicles that are shed into the extracellular environment by tumoral or non-tumoral cells and contribute to cellular communication by delivering micro RNAs (miRNAs). In this study, we aimed to evaluate the role of exosomal miRNAs from colorectal cancer cell lines in tumorigenesis, by affecting cancer-associated fibroblasts (CAFs), which are vital constituents of the tumor microenvironment. To analyze the effect of exosomal miRNA on the tumor microenvironment, migration of the monocytic cell line THP-1 was evaluated via Transwell migration assay using CAFs isolated from colon cancer patients. The migration assay was performed with CAFs ± CCL7-blocking antibody and CAFs that were treated with exosomes isolated from colon cancer cell lines. To identify the associated exosomal miRNAs, miRNA sequencing and quantitative reverse transcription polymerase chain reaction were performed. The migration assay revealed that THP-1 migration was decreased in CCL7-blocking antibody-expressing and exosome-treated CAFs. Colon cancer cell lines contained miRNA let-7d in secreted exosomes targeting the chemokine CCL7. Exosomes from colorectal cancer cell lines affected CCL7 secretion from CAFs, possibly via the miRNA let-7d, and interfered with the migration of CCR2+ monocytic THP-1 cells in vitro.

PD-L1 produced by HaCaT cells under polyinosinic-polycytidylic acid stimulation inhibits melanin production by B16F10 cells.

Skin forms a physical barrier that protects the body against outside agents. The deepest layer of the skin, the stratum basale, contains two cell types: agent-sensing keratinocytes, and melanin-producing melanocytes. Keratinocytes can sense both harmless commensal organisms and harmful pathogens via Toll-like receptors (TLRs), and keratinocytes subsequently drive immune responses. Activation of TLR3 is required for barrier repair because it stimulates essential genes, including tight junction genes, and inflammatory cytokines. Within the basal layer of the skin, resident melanocytes use their dendritic processes to connect with approximately 30-40 neighboring keratinocytes. Most studies have focused on the transfer of melanin-synthesizing melanosomes from melanocytes to keratinocytes, but the potential regulation of melanogenesis by soluble factor(s) produced by keratinocytes remains to be explored. Studying such regulation in vivo is challenging because of the keratinocyte:melanocyte ratio in the epidermis and the location of the cells within the skin. Therefore, in this study, we investigated whether keratinocytes affected melanocyte melanogenesis in vitro under normal or inflammatory conditions. We found that polyinosinic-polycytidylic acid [poly(I:C)] stimulation induced PD-L1 secretion from HaCaT cells and that poly(I:C)-induced PD-L1 inhibited melanin production by B16F10 cells. These data provide key evidence that keratinocytes can alter melanocyte melanogenesis via the production of soluble factors under inflammatory conditions.

Lymphatic endothelial cells promote T lymphocyte migration into lymph nodes under hyperlipidemic conditions.

Lymphatic vessels serve as conduits through which immune cells traffic. Because lymphatic vessels are also involved in lipid transport, their function is vulnerable to abnormal metabolic conditions such as obesity and hyperlipidemia. Exactly how these conditions impact immune cell trafficking, however, is not well understood. Here, we found higher numbers of LYVE-1-positive lymphatic endothelial cells and CD3-positive T cells in the lymph nodes of mice fed high-cholesterol or high-fat diets compared with those of mice fed a normal chow diet. To confirm the effect of fat content on immune cell trafficking, the lymphatic endothelial SVEC4-10 cell line was treated with palmitic acid at a 100 µM concentration. After 24 h, palmitic acid-treated cells exhibited increased expression of podoplanin and vascular growth-associated molecules (VEGFC, VEGFD, VEGFR3, and NRP2) and enhanced tube formation. Microarray analysis showed an increase in pro-inflammatory cytokine and chemokine transcription after palmitic acid treatment. Finally, transwell migration assay confirmed that T cell line moved toward medium previously cultured with palmitic acid-treated SVEC4-10 cells. Together, our results suggest that hyperlipidemia drives lymphatic vessel remodeling and T cell migration toward lymphatic endothelial cells.

Conditioned Medium from Human Tonsil-Derived Mesenchymal Stem Cells Enhances Bone Marrow Engraftment via Endothelial Cell Restoration by Pleiotrophin.

Cotransplantation of mesenchymal stem cells (MSCs) with hematopoietic stem cells (HSCs) has been widely reported to promote HSC engraftment and enhance marrow stromal regeneration. The present study aimed to define whether MSC conditioned medium could recapitulate the effects of MSC cotransplantation. Mouse bone marrow (BM) was partially ablated by the administration of a busulfan and cyclophosphamide (Bu-Cy)-conditioning regimen in BALB/c recipient mice. BM cells (BMCs) isolated from C57BL/6 mice were transplanted via tail vein with or without tonsil-derived MSC conditioned medium (T-MSC CM). Histological analysis of femurs showed increased BM cellularity when T-MSC CM or recombinant human pleiotrophin (rhPTN), a cytokine readily secreted from T-MSCs with a function in hematopoiesis, was injected with BMCs. Microstructural impairment in mesenteric and BM arteriole endothelial cells (ECs) were observed after treatment with Bu-Cy-conditioning regimen; however, T-MSC CM or rhPTN treatment restored the defects. These effects by T-MSC CM were disrupted in the presence of an anti-PTN antibody, indicating that PTN is a key mediator of EC restoration and enhanced BM engraftment. In conclusion, T-MSC CM administration enhances BM engraftment, in part by restoring vasculature via PTN production. These findings highlight the potential therapeutic relevance of T-MSC CM for increasing HSC transplantation efficacy.

Identification of WNT16 as a Predictable Biomarker for Accelerated Osteogenic Differentiation of Tonsil-Derived Mesenchymal Stem Cells In Vitro.

The application of mesenchymal stem cells (MSCs) for treating bone-related diseases shows promising outcomes in preclinical studies. However, cells that are isolated and defined as MSCs comprise a heterogeneous population of progenitors. This heterogeneity can produce variations in the performance of MSCs, especially in applications that require differentiation potential in vivo, such as the treatment of osteoporosis. Here, we aimed to identify genetic markers in tonsil-derived MSCs (T-MSCs) that can predict osteogenic potential. Using a single-cell cloning method, we isolated and established several lines of nondifferentiating (ND) or osteoblast-prone (OP) clones. Next, we performed transcriptome sequencing of three ND and three OP clones that maintained the characteristics of MSCs and determined the top six genes that were upregulated in OP clones. Upregulation of WNT16 and DCLK1 expression was confirmed by real-time quantitative PCR, but only WNT16 expression was correlated with the osteogenic differentiation of T-MSCs from 10 different donors. Collectively, our findings suggest that WNT16 is a putative genetic marker that predicts the osteogenic potential of T-MSCs. Thus, examination of WNT16 expression as a selection criterion prior to the clinical application of MSCs may enhance the therapeutic efficacy of stem cell therapy for bone-related complications, including osteoporosis.

Corrigendum to "Immune Suppressive Effects of Tonsil-Derived Mesenchymal Stem Cells on Mouse Bone-Marrow-Derived Dendritic Cells".

[This corrects the article DOI: 10.1155/2015/106540.].

Conditioned Medium from Tonsil-Derived Mesenchymal Stem Cells Relieves CCl4-Induced Liver Fibrosis in Mice.

BACKGROUND: The liver is an organ with remarkable regenerative capacity; however, once chronic fibrosis occurs, liver failure follows, with high mortality and morbidity rates. Continuous exposure to proinflammatory stimuli exaggerates the pathological process of liver failure; therefore, immune modulation is a potential strategy to treat liver fibrosis. Mesenchymal stem cells (MSCs) with tissue regenerative and immunomodulatory potential may support the development of therapeutics for liver fibrosis. METHODS: Here, we induced hepatic injury in mice by injecting carbon tetrachloride (CCl4) and investigated the therapeutic potential of conditioned medium from tonsil-derived MSCs (T-MSC CM). In parallel, we used recombinant human IL-1Ra, which, as we have previously shown, is secreted exclusively from T-MSCs and resolves the fibrogenic activation of myoblasts. Hepatic inflammation and fibrosis were determined by histological analyses using H&E and Picro-Sirius Red staining. RESULTS: The results demonstrated that T-MSC CM treatment significantly reduced inflammation as well as fibrosis in the CCl4-injured mouse liver. IL-1Ra injection showed effects similar to T-MSC CM treatment, suggesting that T-MSC CM may exert anti-inflammatory and anti-fibrotic effects via the endogenous production of IL-1Ra. The expression of genes involved in fibrosis was evaluated, and the results showed significant induction of alpha-1 type I collagen, transforming growth factor beta, and tissue inhibitor of metalloproteases 1 upon CCl4 injection, whereas treatment with T-MSC CM or IL-1Ra downregulated their expression. CONCLUSIONS: Taken together, these data support the therapeutic potential of T-MSC CM and/or IL-1Ra for the alleviation of liver fibrosis, as well as in treating diseases involving organ fibrosis.

Dexamethasone Promotes Keratinocyte Proliferation by Triggering Keratinocyte Growth Factor in Mast Cells.

BACKGROUND: The skin is a dynamic body organ that can be activated by both central and local hypothalamic-pituitary-adrenal axis systems. This phenomenon might be the crucial explanation why stress can cause relapse of chronic inflammatory skin diseases, such as psoriasis. Here, we determined the effects of mast cells on keratinocyte proliferation under stress hormone stimulation. METHODS: We subcutaneously injected dexamethasone on the shaved back of mice and evaluated histological changes and keratinocyte growth factor (KGF) expression on dermal mast cells. Further, human mast cell line (HMC-1) and keratinocyte cell line (HaCaT) cells were treated with dexamethasone in vitro to observe the extent of proliferation and the expression of KGF. Finally, the supernatants of HMC-1 cells treated with dexamethasone were used for the culture of HaCaT cells to investigate the effect on proliferation. RESULTS: We observed epidermal thickening in dexamethasone-injected mice, accompanied by an increase in the number of KGF-expressing dermal mast cells. Similar to mouse dermal mast cells, KGF was highly expressed in the human mast cell line HMC-1 following stimulation with dexamethasone. Further, dexamethasone-treated mast cells promoted keratinocyte proliferation in vitro. However, the effects of mast cells on keratinocytes were significantly diminished in the presence of anti-KGF-blocking antibodies. CONCLUSION: Taken together, our results show that a stressful environment may disturb skin barrier homeostasis through mast cell-derived KGF expression.

Combination of Docetaxel Plus Savolitinib in Refractory Cancer Patients: A Report on Phase I Trial.

MET amplification is a frequently observed genomic aberration in solid tumors. We conducted a phase I trial to evaluate dose-limiting toxicity (DLT) and recommended phase II dose (RP2D) for the combination therapy. The following dose levels were tested in this single-arm phase I study: docetaxel as an intravenous infusion over 1 hour at 60 mg/m2 once every 3 weeks of a 21-day schedule plus savolitinib (level 1, 200 mg qd; level 2, 400 mg qd; level 3, 600 mg qd; level 4800 mg qd). In total, there were 17 patients enrolled on to this study [7 gastric cancer (GC) patients, 5 melanoma patients, 3 sarcoma patients, and 2 rectal cancer patients]. Most of the patients (14 of 17) were heavily pretreated (≥third line or greater lines of treatment). For the first 3 cohorts (200 mg savolitinib + docetaxel 60 mg/m2, 400 mg savolitinib + docetaxel 60 mg/m2, 600 mg savolitinib + docetaxel 60 mg/m2), there were no DLTs. In the fourth dose cohort (800 mg savolitinib + docetaxel 60 mg/m2), one DLT occurred with generalized edema grade 3 that required intensive management. One GC patient with both MET overexpression (3+) and MET amplification (MET/CEP7 ratio, 7.3) achieved a durable partial response for 297 days, and another MET-amplified GC patient (MET/CEP7 ratio, 7.6) achieved stable disease for 86 days. Due to the higher incidence of G4 neutropenia in cohort 4 (800 mg), we recommend savolitinib 600 mg qd in combination with docetaxel 60 mg/m2 as the RP2D for phase II trial. The combination therapy demonstrated a very promising antitumor activity with durable responses in MET amplified GC patients.

Conditioned medium from human palatine tonsil mesenchymal stem cells attenuates acute graft­vs.­host disease in mice.

Graft-vs.-host disease (GVHD) is a severe and potentially life-threatening complication of hematopoietic stem cell transplantation. Approximately 50% of patients exhibiting GVHD will not benefit from conventional steroid treatment. Although several second­line treatments are available for these patients, their prognoses remain poor due to the increased risk of infection, immunosuppression-mediated toxicity and incomplete GVHD remission, which occurs in the majority of cases. Mesenchymal stem cells (MSCs), a multipotent cell population, possess broad immunosuppressive activity and are a reportedly effective treatment of GVHD. However, the therapeutic effects of conditioned medium from MSCs on GVHD have not been demonstrated. In the present study, the efficacy of conditioned medium from human palatine tonsil­derived MSCs (T­MSC­CM) was validated against GVHD in mice. The suppressive function of T­MSC­CM on immune cell chemotaxis was confirmed in vitro. A systemic infusion of T­MSC­CM in mice with GVHD resulted in prolonged survival, rapid recovery from weight loss and reduced pathological damage in numerous GVHD­targeted organs. Furthermore, lymphocyte gene expression was significantly downregulated in GVHD mice administered T­MSC­CM. These results indicate that T­MSC­CM is a promising cellular agent to prevent or treat transplantation­associated complications such as GVHD.

Benzoxazole derivatives suppress lipopolysaccharide-induced mast cell activation.

Mast cells are central regulators of allergic inflammation that function by releasing various proallergic inflammatory mediators, including histamine, eicosanoids and proinflammatory cytokines. Occasionally, bacterial infections may initiate or worsen allergic inflammation. A number of studies have indicated that activation of lipoxygenase in mast cells positive regulates allergic inflammatory responses by generating leukotrienes and proinflammatory cytokines. In the present study, the effects of benzoxazole derivatives on the lipopolysaccharide (LPS)­induced expression of proinflammatory cytokines, production of histamine and surface expression of co­stimulatory molecules on bone marrow-derived mast cells (BMMCs) were studied. The benzoxazole derivatives significantly reduced the expression of interleukin (IL)­1ß, IL­6, IL­13, tumor necrosis factor­α, perilipin (PLIN) 2, and PLIN3 in BMMCs treated with LPS. Furthermore, histamine production was suppressed in BMMCs treated with LPS, or treated with phorbol-12-myristate-13-acetate/ionomycin. Benzoxazole derivatives marginally affected the surface expression of cluster of differentiation (CD)80 and CD86 on BMMCs in the presence of LPS, although LPS alone did not increase the expression of those proteins. Therefore, benzoxazole derivatives inhibited the secretion of proinflammatory cytokines in mast cells and may be potential candidate anti­allergic agents to suppress mast cell activation.

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-ß, 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 © 2017 John Wiley & Sons, Ltd.

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.

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 ß 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 medium from tonsil­derived mesenchymal stem cells promotes adiponectin production.

Mesenchymal stem cells (MSCs) are often considered to be a good source for the development of regenerative medicine. Previously, we reported that tonsil­derived MSC conditioned medium (T­MSC CM) produces visceral fat reducing effects. As reduced visceral adiposity is closely associated with an increase in circulating adiponectin, the present study investigated the effects of T­MSC CM on adiponectin production. T­MSC CM was collected from previously isolated and characterized T­MSCs and injected into senescence­accelerated mouse prone 6 mice, which exhibit characteristics of aging and obesity. The results demonstrated a reduction in mouse weight and epididymal adipose tissue (eAT) mass following injection of T­MSC CM. Significant increases in adiponectin expression in the eAT, and total and high molecular weight (HMW) adiponectin in the circulation were observed in the T­MSC CM­injected mice compared with control mice using reverse transcription­quantitative polymerase chain reaction, western blot analysis and ELISA. In 3T3­L1 adipocytes, T­MSC CM treatment increased adiponectin secretion and multimerization, as detected using western blotting under non­reducing and non­heat­denaturing conditions. Furthermore, glucose oxidase was used to induce oxidative stress in 3T3­L1 adipocytes and it was observed that T­MSC CM reduced reactive oxygen species production and the expression of certain oxidative stress markers. In addition, the results also demonstrated that the production of HMW adiponectin was increased, which indicates that T­MSC CM may enhance adiponectin multimerization via amelioration of oxidative stress. Further studies are required to elucidate anti­oxidant molecules secreted from T­MSCs, and these results highlight the potential therapeutic relevance of T­MSC CM for the treatment of obesity or obesity­associated diseases.

Th17 cell-mediated immune responses promote mast cell proliferation by triggering stem cell factor in keratinocytes.

Although mast cells are traditionally thought to function as effector cells in allergic responses, they have increasingly been recognized as important regulators of various immune responses. Mast cells mature locally; thus, tissue-specific influences are important for promoting mast cell accumulation and survival in the skin and the gastrointestinal tract. In this study, we determined the effects of keratinocytes on mast cell accumulation during Th17-mediated skin inflammation. We observed increases in dermal mast cells in imiquimod-induced psoriatic dermatitis in mice accompanied by the expression of epidermal stem cell factor (SCF), a critical mast cell growth factor. Similar to mouse epidermal keratinocytes, SCF was highly expressed in the human HaCaT keratinocyte cell line following stimulation with IL-17. Further, keratinocytes promoted mast cell proliferation following stimulation with IL-17 in vitro. However, the effects of keratinocytes on mast cells were significantly diminished in the presence of anti-CD117 (stem cell factor receptor) blocking antibodies. Taken together, our results revealed that the Th17-mediated inflammatory environment promotes mast cell accumulation through keratinocyte-derived SCF.