Negative impact of bone-marrow-derived mesenchymal stem cells on dextran sulfate sodium-induced colitis

AIM:To investigate the effects of mesenchymal stem cells(MSCs)on dextran sulfate sodium-induced inflammatory bowel disease(IBD).METHODS:C57BL/6 mice were fed 3.5%(g/L)dextran sulfate sodium.On day seven,the mice received intraperitoneal injections of 1×106 MSCs.The survival rate,disease activity index values,and body weight,were monitored daily.On day ten,colon lengths and histopathologic changes were assessed.In addition,immunoregulatory changes following MSC administration were evaluated by determining the levels of effector T cell responses in the spleen and mesenteric lymph nodes,and the expression levels of inflammatory cytokines in homogenized colons.RESULTS:Intraperitoneal administration of MSCs did not prevent development of colitis and did not reduce the clinicopathologic severity of IBD.No significant difference was evident in either survival rate or disease activity index score between the control and MSCtreated group.Day ten-sacrificed mice exhibited no significant difference in either colon length or histopathologic findings.Indeed,the MSC-treated group exhibited elevated levels of interleukin(IL)-6 and transforming growth factor-β,and a reduced level of IL-10,in spleens,mesenteric lymph nodes,and homogenized colons.The IL-17 level was lower in the mesenteric lymph nodes of the MSC-treated group(P=0.0126).In homogenized colons,the IL-17 and tumor necrosis factor-α(P=0.0092)expression levels were also lower in the treated group.CONCLUSION:MSC infusion provided no significanthistopathologic or clinical improvement,thus representing a limited therapeutic approach for IBD.Functional enhancement of MSCs is needed in further study.

A critical regulation of Th2 cell responses by RORa in allergic asthma

Allergic asthma is a chronic inflammatory disease of the lung and the airway,which is characterized by aberrant type 2 immune responses to otherwise unharmful aeroallergens.While the central role of Th2 cells and type 2 cytokines in the pathogenesis of allergic asthma is well documented,the regulation and plasticity of Th2 cells remain incompletely understood.By using an animal model of allergic asthma in IL-4-reporter mice,we found that Th2 cells in the lung expressed higher levels of Rora than those in the lymph nodes,and that treatment with an RORa agonist SRI 078 resulted in diminished Th2 cell responses in vivo.To determine the T cell-intrinsic role of RORa in allergic asthma in vivo,we established T cell-specific RORa-deficient^(f/f)fyf(Cd4creRora^(f/f))mice.Upon intranasal allergen challenges,Cd4creRora^(f/f)mice exhibited a significantly increased Th2 cells in the lungs and the airway and showed an enhanced eosinophilic inflammation compared to littermate control mice.Studies with Foxp3^(YFP-cre)Rora^(f/f)mice and CD^(8+)T cell depletion showed that the increased Th2 cell responses in the Cd4creRora^(f/f)mice were independent of Treg cells and CD^(8+)T cells.Our findings demonstrate a critical regulatory role of RORa in Th2 cells,which suggest that RORa agonists could be effective for the treatment of allergic diseases.

Human mesenchymal stem cells derived from umbilical cord and bone marrow exert immunomodulatory effects in different mechanisms

BACKGROUND Mesenchymal stem cells(MSCs)are an attractive tool to treat graft-versus-host disease because of their unique immunoregulatory properties.Although human bone marrow-derived MSCs(BM-MSCs)were the most widely used MSCs in cell therapy until recently,MSCs derived from human umbilical cords(UC-MSCs)have gained popularity as cell therapy material for their ethical and noninvasive collection.AIM To investigate the difference in mechanisms of the immunosuppressive effects of UC-MSCs and BM-MSCs.METHODS To analyze soluble factors expressed by MSCs,such as indolamine 2,3-dioxygenase,cyclooxygenase-2,prostaglandin E2 and interleukin(IL)-6,inflammatory environments in vitro were reconstituted with combinations of interferon-gamma(IFN-γ),tumor necrosis factor alpha and IL-1βor with IFN-γalone.Activated T cells were cocultured with MSCs treated with indomethacin and/or anti-IL-10.To assess the ability of MSCs to inhibit T helper 17 cells and induce regulatory T cells,induced T helper 17 cells were cocultured with MSCs treated with indomethacin or anti-IL-10.Xenogeneic graft-versus-host disease was induced in NOG mice(NOD/Shi-scid/IL-2Rγnull)and UC-MSCs or BM-MSCs were treated as cell therapies.RESULTS Our data demonstrated that BM-MSCs and UC-MSCs shared similar phenotypic characteristics and immunomodulation abilities.BM-MSCs expressed more indolamine 2,3-dioxygenase after cytokine stimulation with different combinations of IFN-γ,tumor necrosis factor alpha-αand IL-1βor IFN-γalone.UC-MSCs expressed more prostaglandin E2,IL-6,programmed death-ligand 1 and 2 in the in vitro inflammatory environment.Cyclooxygenase-2 and IL-10 were key factors in the immunomodulatory mechanisms of both MSCs.In addition,UC-MSCs inhibited more T helper 17 cells and induced more regulatory T cells than BM-MSCs.UC-MSCs and BM-MSCs exhibited similar effects on attenuating graft-versus-host disease.CONCLUSION UC-MSCs and BM-MSCs exert similar immunosuppressive effects with different mechanisms involved.These findings suggest that UC-MSCs have distinct immunoregulatory functions and may substitute BM-MBSCs in the field of cell therapy.

The emerging role of Arid5a in cancer: A new target for tumors

AT-rich interactive domain 5a (Arid5a) is a member of the arid family of proteins, which contain a helix-turn-helix domain and an ability to bind to nucleic acids. Current evidence suggests that Arid5a performs dual functions as a transcription factor and an RNA-binding protein in immune, nonimmune, and/ or tumor cells depending on its cellular localization. The contribution of Arid5a to the development of inflammation, autoimmunity, and obesity through its transcriptional and posttranscriptional regulatory functions has broadly been reviewed. Recent studies have indeed revealed an association of Arid5a with cancers, including breast, pancreatic, colorectal, and lung cancers and glioma. Notably, Arid5a affects various aspects of cellular homeostasis, including invasion, metastasis, epithelial-to-mesenchymal transition, immune evasion, adipogenesis and M1-like tumor-associated macrophage (TAM)-to-M2-like TAM transition. This review aims to summarize current knowledge of Arid5a from a cancer perspective and highlights recent advances in Arid5a-related cancer research. This review may improve the understanding of Arid5a-mediated molecular mechanisms and their relevance to cancers.

Tumor-specific memory CD8^(+)T cells are strictly resident in draining lymph nodes during tumorigenesis

The functional exhaustion of CD8^(+)T cells represents a fundamental hallmark of chronic viral infection and cancer and,in both scenarios,is driven by prolonged exposure to persistent cognate antigens in the context of an immunoinhibitory microenvironment.Exhausted CD8^(+)T cells upregulate the expression of a wide diversity of coinhibitory immunoreceptors(also referred to as immune checkpoint receptors),such as PD-1,Tim-3,LAG-3,and TIGIT.Concomitantly,exhausted CD8^(+)T cells lose their potential to differentiate into functional memory cells and are characterized by hierarchical loss of effector function,leading to compromised tumor control and viral eradication[1,2].