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Osteoarthritis (OA) is characterized by cartilage degradation and chronic joint inflammation. Mesenchymal stem cells (MSCs) have shown promising results in OA,but their mechanism of action is not fully understood. We hypothesize that MSCs polarize macrophages,which are strongly associated with joint inflammation to more homeostatic sub-types. We tracked ferumoxytol (Feraheme™,iron oxide nanoparticle)-labeled murine MSCs (Fe-MSCs) in murine OA joints,and quantified changes to joint inflammation and fibrosis. 10-week-old C57BL/6 male mice (n = 5/group) were induced to undergo osteoarthritis by destabilization of medical meniscus (DMM) or sham surgery. 3 weeks post-surgery,mice were injected intra-articularly with either fluorescent dye-(DiR) labeled or DiR-Fe-MSC or saline to yield 4 groups (n = 5 per group for each timepoint [1,2 and 4weeks]). 4 weeks after injection,mice were imaged by MRI,and scored for i) OARSI (Osteoarthritis Research Society International) to determine cartilage damage; ii) immunohistochemical changes in iNOS,CD206,F4/80 and Prussian Blue/Sca-1 to detect pro-inflammatory,homeostatic and total macrophages and ferumoxytol -labeled MSCs respectively,and iii) Masson's Trichrome to detect changes in fibrosis. Ferumoxytol-labeled MSCs persisted at greater levels in DMM vs. SHAM-knee joints. We observed no difference in OARSI scores between MSC and vehicle groups. Sca-1 and Prussian Blue co-staining confirmed the ferumoxytol label resides in MSCs,although some ferumoxytol label was detected in proximity to MSCs in macrophages,likely due to phagocytosis of apoptotic MSCs,increasing functionality of these macrophages through MSC efferocytosis. MRI hypertintensity scores related to fluid edema decreased in MSC-treated vs. control animals. For the first time,we show that MSC-treated mice had increased ratios of {\%}CD206+: {\%}F4/80+ (homeostatic macrophages) (p{\textless}0.05),and decreased ratios of {\%}iNOS+: {\%}F4/80+ macrophages (p{\textless}0.01),supporting our hypothesis that MSCs may modulate synovial inflammation. View Publication

A rapidly increasing number of reports on dysregulated long intergenic non-coding RNA (lincRNA) expression across numerous types of cancers indicates that aberrant lincRNA expression may be a major contributor to tumorigenesis. Marek's disease (MD) is a T cell lymphoma of chickens induced by Marek's disease virus (MDV). Although we have investigated the roles of lincRNAs in bursa tissue of MDV-infected chickens in previous studies,the molecular mechanisms of lincRNA functions in T cells remain poorly understood. In the present study,Linc-GALMD1 was identified from CD4+ T cells and MSB1 cells,and its expression was significantly downregulated in MD-resistant line of birds in response to MDV challenge. Furthermore,loss-of-function experiments indicated that linc-GALMD1 significantly affected the expression of 290 genes in trans. Through integrated analysis of differentially expressed genes (DEGs) induced by MDV and linc-GALMD1,we found that IGLL1 gene expression levels had a positive correlation with the degree of MD infection and could potentially serve as an indicator for clinical diagnosis of MD. Moreover,an interaction between MDV and linc-GALMD1 was also observed. Accordingly,chicken embryonic fibroblast cells were inoculated with MDV with and without the linc-GALMD1 knockdown,and the data showed that linc-GALMD1 could repress MDV gene expression during the course of MDV infection. These findings uncovered a role of linc-GALMD1 as a viral gene regulator and suggested a function of linc-GALMD1 contributing to tumor suppression by coordinating expression of MDV genes and tumor-related genes and regulating immune responses to MDV infection. View Publication

Early studies in exercise immunology suggested acute bouts of exercise had an immunosuppressive effect in human subjects. However,recent data,show acute bouts of combined aerobic and resistance training increase both lymphocyte activation and proliferation. We quantified resistance exercise-induced changes in the activation state of CD4+ T lymphocytes via surface protein expression and using a medically relevant model of infection (HIV-1). Using a randomized cross-over design,10 untrained subjects completed a control and exercise session. The control session consisted of 30-min seated rest while the exercise session entailed 3 sets × 10 repetitions of back squat,leg press,and leg extensions at 70{\%} 1-RM with 2-min rest between each set. Venous blood samples were obtained pre/post each session. CD4+ T lymphocytes were isolated from whole blood by negative selection. Expression of activation markers (CD69 {\&} CD25) in both nonstimulated and stimulated (costimulation through CD3+ CD28) cells were assessed by flow cytometry. Resistance exercised-induced effects on intracellular activation was further evaluated via in vitro infection with HIV-1. Nonstimulated CD4+ T lymphocytes obtained postexercise exhibited elevated CD25 expression following 24 h in culture. Enhanced HIV-1 replication was observed in cells obtained postexercise. Our results demonstrate that an acute bout of resistance exercise increases the activation state of CD4+ T lymphocytes and results in a greater susceptibility to HIV-1 infection in vitro. These findings offer further evidence that exercise induces activation of T lymphocytes and provides a foundation for the use of medically relevant pathogens as indirect measures of intracellular activation. View Publication

BACKGROUND Human pancreata contain many types of cells,such as endocrine islets,acinar,ductal,fat,and mesenchymal stromal cells (MSCs). MSCs are important and shown to have a promising therapeutic potential to treat various disease conditions. METHODS We investigated intra-pancreatic tissue-derived (IPTD) MSCs isolated from tissue fractions that are routinely discarded during pancreatic islet isolation of human cadaveric donors. Furthermore,whether pro-angiogenic and anti-inflammatory properties of these cells could be enhanced was investigated. RESULTS IPTD-MSCs were expanded in GMP-compatible CMRL-1066 medium supplemented with 5{\%} human platelet lysate (hPL). IPTD-MSCs were found to be highly pure,with {\textgreater} 95{\%} positive for CD90,CD105,and CD73,and negative for CD45,CD34,CD14,and HLA-DR. Immunofluorescence staining of pancreas tissue demonstrated the presence of CD105+ cells in the vicinity of islets. IPTD-MSCs were capable of differentiation into adipocytes,chondrocytes,and osteoblasts in vitro,underscoring their multipotent features. When these cells were cultured in the presence of a low dose of TNF-$\alpha$,gene expression of tumor necrosis factor alpha-stimulated gene-6 (TSG-6) was significantly increased,compared to control. In contrast,treating cells with dimethyloxallyl glycine (DMOG) (a prolyl 4-hydroxylase inhibitor) enhanced mRNA levels of nuclear factor erythroid 2-related factor 2 (NRF2) and vascular endothelial growth factor (VEGF). Interestingly,a combination of TNF-$\alpha$ and DMOG stimulated the optimal expression of all three genes in IPTD-MSCs. Conditioned medium of IPTD-MSCs treated with a combination of DMOG and TNF-$\alpha$ contained higher levels of pro-angiogenic (VEGF,IL-6,and IL-8) compared to controls,promoting angiogenesis of human endothelial cells in vitro. In contrast,levels of MCP-1,a pro-inflammatory cytokine,were reduced in the conditioned medium of IPTD-MSCs treated with a combination of DMOG and TNF-$\alpha$. CONCLUSIONS The results demonstrate that IPTD-MSCs reside within the pancreas and can be separated as part of a standard islet-isolation protocol. These IPTD-MSCs can be expanded and potentiated ex vivo to enhance their anti-inflammatory and pro-angiogenic profiles. The fact that IPTD-MSCs are generated in a GMP-compatible procedure implicates a direct clinical application. View Publication

Reduced serum testosterone (T),or hypogonadism,affects millions of men and is associated with many pathologies,including infertility,cardiovascular diseases,metabolic syndrome,and decreased libido and sexual function. Administering T-replacement therapy (TRT) reverses many of the symptoms associated with low T levels. However,TRT is linked to side effects such as infertility and increased risk of prostate cancer and cardiovascular diseases. Thus,there is a need to obtain T-producing cells that could be used to treat hypogonadism via transplantation and reestablishment of T-producing cell lineages in the body. T is synthesized by Leydig cells (LCs),proposed to derive from mesenchymal cells of mesonephric origin. Although mesenchymal cells have been successfully induced into LCs,the limited source and possible trauma to donors hinders their application to clinical therapies. Alternatively,human induced pluripotent stem cells (hiPSCs),which are expandable in culture and have the potential to differentiate into all somatic cell types,have become the emerging source of autologous cell therapies. We have successfully induced the differentiation of hiPSCs into either human Leydig-like (hLLCs) or adrenal-like cells (hALCs) using chemically defined culture conditions. Factors critical for the development of LCs were added to both culture systems. hLLCs expressed all steroidogenic genes and proteins important for T biosynthesis,synthesized T rather than cortisol,secreted steroid hormones in response to dibutyryl-cAMP and 22(R)-hydroxycholesterol,and displayed ultrastructural features resembling LCs. By contrast,hALCs synthesized cortisol rather than T. The success in generating hiPSC-derived hLLCs with broad human LC (hLC) features supports the potential for hiPSC-based hLC regeneration. View Publication

Spinal cord injury (SCI) is one of the most debilitating injuries,and transplantation of stem cells in a scaffold is a promising strategy for treatment. However,stem cell treatment of SCI has been severely impaired by the increased generation of reactive oxygen species in the lesion microenvironment,which can lead to a high level of stem cell death and dysfunction. Herein,a MnO2 nanoparticle (NP)-dotted hydrogel is prepared through dispersion of MnO2 NPs in a PPFLMLLKGSTR peptide modified hyaluronic acid hydrogel. The peptide-modified hydrogel enables the adhesive growth of mesenchymal stem cells (MSCs) and nerve tissue bridging. The MnO2 NPs alleviate the oxidative environment,thereby effectively improving the viability of MSCs. Transplantation of MSCs in the multifunctional gel generates a significant motor function restoration on a long-span rat spinal cord transection model and induces an in vivo integration as well as neural differentiation of the implanted MSCs,leading to a highly efficient regeneration of central nervous spinal cord tissue. Therefore,the MnO2 NP-dotted hydrogel represents a promising strategy for stem-cell-based therapies of central nervous system diseases through the comprehensive regulation of pathological microenvironment complications. View Publication

Cytotoxic chemotherapies could cause the dysregulation of hematopoiesis and even put patients at increased risk of hematopoietic malignancy. Therapy-related leukemia is mainly caused by cytotoxic chemotherapy-induced genetic mutations in hematopoietic stem/progenitor cells (HSPCs). In addition to the intrinsic mechanism,some extrinsic events occurring in the bone marrow (BM) microenvironment are also possible mechanisms involved in genetic alteration. In the present study,we investigated the damage to BM stromal cells induced by a chemotherapy drug,daunorubicin (DNR) and further identified the DNA damage in hematopoietic cells caused by drug-treated stromal cells. It was found that treatment with DNR in mice caused a temporary reduction in cell number in each BM stromal cell subpopulation and the impairment of clonal growth potential in BM stromal cells. DNR treatment led to a tendency of senescence,generation of intracellular reactive oxygen species,production of cytokines and chemokines,and dysfunction of mitochondrial in stromal cells. Transcriptome microarray data and gene ontology (GO) or gene set enrichment analysis (GSEA) showed that differentially expressed genes that were down-regulated in response to DNR treatment were significantly enriched in mitochondrion function,and negative regulators of reactive oxygen species. Surprisingly,it was found that DNR-treated stromal cells secreted high levels of H2O2 into the culture supernatant. Furthermore,coculture of hematopoietic cells with DNR-treated stromal cells led to the accumulation of DNA damage as determined by the levels of histone H2AX phosphorylation and 8-oxo-2'-deoxyguanosine in hematopoietic cells. Overall,our results suggest that DNR-induced BM stromal cell damage can lead to genomic instability in hematopoietic cells. View Publication

Secreted factors derived from Lactobacillus are able to dampen pro-inflammatory cytokine responses. Still,the nature of these components and the underlying mechanisms remain elusive. Here,we aimed to identify the components and the mechanism involved in the Lactobacillus-mediated modulation of immune cell activation. PBMC were stimulated in the presence of the cell free supernatants (CFS) of cultured Lactobacillus rhamnosus GG and Lactobacillus reuteri DSM 17938,followed by evaluation of cytokine responses. We show that lactobacilli-CFS effectively dampen induced IFN-$\gamma$ and IL-17A responses from T- and NK cells in a monocyte dependent manner by a soluble factor. A proteomic array analysis highlighted Lactobacillus-induced IL-1 receptor antagonist (ra) as a potential candidate responsible for the IFN-$\gamma$ dampening activity. Indeed,addition of recombinant IL-1ra to stimulated PBMC resulted in reduced IFN-$\gamma$ production. Further characterization of the lactobacilli-CFS revealed the presence of extracellular membrane vesicles with a similar immune regulatory activity to that observed with the lactobacilli-CFS. In conclusion,we have shown that lactobacilli produce extracellular MVs,which are able to dampen pro-inflammatory cytokine responses in a monocyte-dependent manner. View Publication

Tissue-resident memory CD8+ T (Trm) cells mediate potent local innate and adaptive immune responses and play a central role against solid tumors. However,whether Trm cells cross-talk with dendritic cells (DCs) to support anti-tumor immunity remains unclear. Here we show that antigen-specific activation of skin Trm cells leads to maturation and migration to draining lymph nodes of cross-presenting dermal DCs. Tumor rejection mediated by Trm cells triggers the spread of cytotoxic CD8+ T cell responses against tumor-derived neo- and self-antigens via dermal DCs. These responses suppress the growth of intradermal tumors and disseminated melanoma lacking the Trm cell-targeted epitope. Moreover,analysis of RNA sequencing data from human melanoma tumors reveals that enrichment of a Trm cell gene signature associates with DC activation and improved survival. This work unveils the ability of Trm cells to amplify the breath of cytotoxic CD8+ T cell responses through DCs,thereby strengthening anti-tumor immunity. View Publication

Experimental autoimmune uveoretinitis (EAU) is a mouse model of human autoimmune uveitis marked by ocular autoantigen-specific regulatory immunity in the spleen. The melanocortin 5 receptor (MC5r) and adenosine 2 A receptor (A2Ar) are required for induction of post-EAU regulatory T cells (Tregs) which provide resistance to EAU. We show that blocking the PD-1/PD-L1 pathway prevented suppression of EAU by post-EAU Tregs. A2Ar induction of PD-1+FoxP3+ Tregs in uveitis patients was similar compared to healthy controls,but was significantly reduced with melanocortin stimulation. Further,lower body mass index correlated with responsiveness to stimulation of this pathway. These observations indicate an importance of the PD-1/PD-L1 pathway to provide resistance to relapsing uveitis and shows a reduced capacity of uveitis patients to induce Tregs when stimulated through melanocortin receptors,but that it is possible to bypass this part of the pathway through direct stimulation of A2Ar. View Publication