Effect of 3,3'-diselenodipropionic Acid on Dextran Sodium Sulfate-Induced Ulcerative Colitis in Mice.

3,3'-Diselenodipropionic acid (DSePA), a synthetic organoselenium compound, has received considerable attention because of its antioxidant properties and safety. Its protective effect against dextran sodium sulfate (DSS)-induced mouse ulcerative colitis (UC) and the role of T helper 17 (Th17) cell proliferation were investigated. Fifty C57BL/6 male mice were randomly assigned to one of five groups: control (Con), DSePA, DSS, low-dose DSePA (LSe), and high-dose DSePA (HSe). Mice in the DSS, LSe, and HSe groups drank 2% DSS to induce UC, and received normal saline, 1 and 2 mg/mL DSePA solution by intraperitoneal injection, respectively. The DSePA group only received 2 mg/mL DSePA solution. After 5 weeks, DSS challenge induced UC in the mice, which manifested as decreased body weight, shortened colon length, the loss of goblet cells, activated proliferating cells, and multiple signs of intestinal lesions by histological observation, all of which were reversed to varying degrees by DSePA administration. DSS upregulated the colonic protein expression of the macrophage marker F4/80 and proinflammatory cytokines (IL-1ß, IL-6, and TNFα), whereas DSePA administration downregulated the expression of these factors. DSS upregulated the mRNA expression of retinoic acid receptor-related orphan receptor γt (RORγt, mainly expressed in Th17 cells), IL-17A, and IL-17F and the levels of IL-17A and IL-17F in the colon, whereas DSePA administration decreased them. No difference was observed between the Con group and the DSePA group without DSS induction. Thus, DSePA administration ameliorated DSS-induced UC by regulating Th17-cell proliferation and the secretion of proinflammatory cytokines.

The association between parental and neonatal BCG vaccination and neonatal T helper 17 cell expansion.

BACKGROUND: Bacille Calmette-Guérin (BCG) vaccination reduces the severity of neonatal infections; this effect appears enhanced if the mother has received BCG. We performed immunophenotyping of the T-cell subset and characterized T-cell proliferation responses to assess possible immune response pathways. METHODS: Healthy BCG-vaccinated (n = 8) and unvaccinated (n = 9) neonates born by elective caesarean section were sampled 3 weeks after birth. We compared a wide panel of intracellular cytokine and cell surface expression markers as well as proliferation response in T-cells between BCG-vaccinated and unvaccinated neonates, stratified by parental BCG status. RESULTS: For all BCG-vaccinated neonates and 3 of 9 unvaccinated neonates that served as controls, both parents had a BCG scar. Th17 (CD4 + IL-17+) prevalence as percentage of total CD4 + T-cells was expanded 4-fold in BCG-vaccinated compared to unvaccinated, being 11.6% [3.6-19.6%] vs 2.8% [1.0-6.6%]. Th17 counts for 3 unvaccinated neonates born to BCG-vaccinated parents was comparable to vaccinated neonates, and higher than remaining controls, parental BCG = 8.5% [4.4-8.9%] vs 1.8% [0.8-3.3%] for no parental BCG (median [interquartile range] for all data). CONCLUSION: Among neonates born to BCG-vaccinated parents, the prevalence of Th17 cells, important in the response against bacterial infections, was substantially elevated. The interaction between neonatal and parental BCG for Th17 responses and the importance remains to be further investigated.

Effect of Asiaticoside on Expression of Th17/Treg Cells in DBA/1 Mice with Collagen-Induced Arthritis / 中国实验方剂学杂志

ObjectiveTo observe the effect of asiaticoside （AC） on the expression of T helper 17 （Th17） cells and regulatory T （Treg） cells in DBA/1 mice with collagen-induced arthritis （CIA）. MethodMale SPF DBA/1 mice were randomized into six groups according to body weight： control group， CIA group， methotrexate group （MTX group， ip， 0.5 mg·kg-1）， and AC low-， medium-， and high-dose groups （ig， 5， 15， 45 mg·kg-1， respectively）. Modeling was performed in rats other than the control group. To be specific， they were immunized with bovine type Ⅱ collagen and complete Freund's adjuvant on the first day and with bovine type Ⅱ collagen and incomplete Freund's adjuvant on the 21st day. Administration began on the day of the second immunization， once a day for 28 days. On the 49th day， related tissues were collected. Then， hematoxylin-eosin （HE） staining was performed to observe the pathological changes of the joints. Immunohistochemical method was used to detect the expression of interleukin-17 （IL-17） and forkhead box protein-3 （FoxP3）， the markers of Th17 and Treg cells， respectively， immunofluorescence double staining the expression of IL-17 and FoxP3 in CD4+T cells of mouse joint tissue， and flow cytometry the proportions of Th17 and Treg cells in mouse lymph nodes. ResultCompared with the control group， CIA group demonstrated joint disorder， damage of articular cartilage and bone， severe bone erosion （P<0.01）， increase in stained CD4 and IL-17 and the integral absorbance （IA） （P<0.01）， decrease in stained FoxP3 and the IA （P<0.01）， rise of Th17/Treg ratio （P<0.01）， elevation of Th17 expression in mouse lymph nodes （P<0.01）， and reduction in Treg expression （P<0.01）. Compared with CIA group， MTX group and three AC groups showed normal joints， alleviated bone erosion and damage， intact and smooth joint surface， and decrease in stained IL-17 and IA （P<0.05， P<0.01）， and MTX group and AC medium-dose and high-dose groups registered decrease in stained CD4 and IA （P<0.01） and reduction in Th17/Treg ratio （P<0.05， P<0.01）. Moreover， AC medium-dose and high-dose groups showed rise in stained FoxP3 and IA （P<0.05， P<0.01）. In the lymph nodes of mice， decrease in expression of Th17 cells （P<0.05， P<0.01） and the increase in expression of Treg cells （P<0.05， P<0.01） were observed in all the three AC group. ConclusionAC can regulate Th17/Treg balance by inhibiting the expression of Th17 cells and promoting the expression of Treg cells in CIA mice.

Staphylococcus aureus and Hyper-IgE Syndrome.

Hyper-immunoglobulin E syndrome (HIES) is a primary immunodeficiency disease characterized by recurrent Staphylococcus aureus (S. aureus) infections, eczema, skeletal abnormalities and high titers of serum immunoglobulin E. Although the genetic basis of HIES was not known for almost a half century, HIES most frequently exhibits autosomal dominant trait that is transmitted with variable expressivity. Careful genetic studies in recent years identified dominant-negative mutations in human signal transducer and activator of transcription 3 (STAT3) gene as the cause of sporadic and dominant forms of HIES. The STAT3 mutations were localized to DNA-binding, SRC homology 2 (SH2) and transactivating domains and disrupted T helper 17 (TH17) cell differentiation and downstream expression of TH17 cytokines IL-17 and IL-22. Deficiency of IL-17 and IL-22 in turn is responsible for suboptimal expression of anti-staphylococcal host factors, such as neutrophil-recruiting chemokines and antimicrobial peptides, by human keratinocytes and bronchial epithelial cells. TH17 cytokines deficiency thereby explains the recurrent staphylococcal lung and skin infections of HIES patients.

PPARα suppresses Th17 cell differentiation through IL-6/STAT3/RORγt pathway in experimental autoimmune myocarditis.

Family members of peroxisome proliferator-activated receptors (PPARs), such as PPARγ, have been shown to be effective in regulating T helper 17 (Th17) cell differentiation. However, whether PPARα, another important family member of PPARs, contributes to Th17 cell differentiation remains controversial. In the present study, we show that PPARα may be a negative regulator of Th17 cell differentiation. In CD4+ T cells from PPARα knockout mice, PPARα deficiency enhances IL-17 and IL-6 levels and promotes Th17 cell differentiation. In contrast, in CD4+ T cells from wild type mice, PPARα activation suppresses Th17 cell differentiation. Furthermore, IL-6 neutralizing antibody dose-dependently reduces the activity of STAT3 and down-regulates the protein expression of RORγt in CD4+ T cells from PPARα knockout mice but has no effect on that of wild type mice. On the other hand, in isolated CD4+ T cells from experimental autoimmune myocarditis (EAM) rats, PPARα agonist Fenofibrate decreased the expression of IL-17 and RORγt, increased the expression of Foxp3, while PPARα antagonist MK886 reversed these effects. Importantly, in vivo activation of PPARα ameliorates EAM by suppressing Th17 cell differentiation through reducing the expression of RORγt and phosphorylated STAT3 that are upregulated in EAM hearts. These results imply that PPARα suppresses Th17 cell differentiation through IL-6/STAT3/RORγt signaling pathway and suggest that PPARα may become a molecular target for treating autoimmune myocarditis.