Taurine promotes B-cell activation by interaction with the VH /VL framework regions of B-cell receptor.

Taurine (Tau) is a special sulphur-containing amino acid and has been widely used as a dietary supplement. Although Tau exists in lymphocytes in large quantities, the physiological significance of Tau to modulate human immunity is unknown. In the present study, we first found that Tau regulates the B-cell receptor (BCR)-mediated signal transduction and induces the B cells activation. The IgG production of mice after ovalbumin immunization was also increased by Tau administration. Moreover, the isothermal titration calorimetry and surface plasmon resonance analysis have shown that Tau specifically bound to the IgG2a-BCR. The Tau could bind to IgG F(ab')2 regions via fluorescence spectroscopy analysis. In the molecular docking analysis, Tau bound to the framework regions (FRs) of variable region of the heavy chains (VH ) and in the light chains (VL ) of IgG2a-BCR. Our results suggested that Tau could improve the activation of B cells by interaction with the VH /VL FRs of BCR.

Ginsenoside Rg1 modulates intestinal microbiota and supports re-generation of immune cells in dexamethasone-treated mice.

Ginsenoside Rg1 is one of the major ginsenosides found in roots of Panax ginseng and Panax notoginseng. Ginsenoside Rg1 is known to possess various biological activities including immunity enhancement activity. However, it is not clear whether the regulation of immune function by Rg1 is related to the intestinal microbiota. In the present study, the immuno-modulatory and gut microbiota-reshaping effects of ginsenoside Rg1 were evaluated. Ginsenoside Rg1 acts as an immune-enhancing agent to increase spleen index and the number of T, B and dendritic cells in dexamethasone (Dex)-treated mice. Ginsenoside Rg1 also increased the production of sIgA and regulated the expression of interleukin 2 (IL-2), IL-4, IL-10 and IFN-γ. Meanwhile, Rg1 administration regulated the structure of intestinal microbiota. The relative abundance of mouse intestinal microbial groups, such as Alistipes, Ruminococcaceae, Lachnospiraceae, and Roseburia were increased by Rg1 administration, whereas a decrease in the potential pathogens like Helicobacteraceae, Dubosiella, Mycoplasma, Alloprevotella, Allobaculum was observed. Moreover, Rg1 metabolites of Lachnospiraceae bacterium enhanced the proliferation of CD4+ T cells and T regulatory (Treg) cells. Ginsenoside Rg1 improved the inflammatory condition of the colonic tissue and repaired the destructed mucosal barrier. This study suggested that Rg1 strengthens immunity with regulating the homeostasis of intestinal microbiota in mice.

Loss of core fucosylation suppressed the humoral immune response in Salmonella typhimurium infected mice.

BACKGROUND: The humoral immune response is pivotal to protect the host from Salmonella typhimurium (S. typhimurium) infection. Previously, we found that core fucosylation catalyzed by core fucosyltransferase (Fut8) could regulate the immune responses. However, the role of core fucosylation during S. typhimurium infection remains unclear. METHODS: To demonstrate the role of Fut8 in S. typhimurium infection, we infected Fut8+/+ and Fut8-/- mice using S. typhimurium. The production of antiserum against the S. typhimurium was detected. The expression of T and B cell activation-related genes during S. typhimurium infection was analyzed. The role of core fucosylation on CD4+ T-B cell interaction and B cell generation was investigated during S. typhimurium infection. The production of sIgA was compared between Fut8+/+ and Fut8-/- mice. RESULTS: Compared to Fut8+/+ mice, the number of S. typhimurium colonized in the cecum was markedly increased in Fut8-/- mice. The production of the IgG and sIgA specific for S. typhimurium was significantly decreased in Fut8-/- mice. Moreover, loss of Fut8 decreased the induction of Th2-type cytokines from splenic cells of Fut8-/- mice during S. typhimurium infection. In addition, we found that the core fucosylation regulated the interaction between B and T cells in the lipid raft formation. CONCLUSION: Core fucosylation plays important roles in host defence against S. typhimurium infection.

FoxO1 controls the expansion of pre-B cells by regulating the expression of interleukin 7 receptor α chain and its signal pathway.

Forkhead box O1 (FoxO1) has a crucial role in the early B cell development. To understand the functional importance of FoxO1 gene in the early B cell expansion, we established a FoxO1 knockdown model using 70Z/3 pre-B cell line. The FoxO1 knockdown 70Z/3 cells (70Z/3-KD cells) showed the down-regulated expression of interleukin 7 receptor α chain (IL-7Rα). Moreover, the signaling via IL-7Rα was significantly attenuated in the 70Z/3-KD cells, and this alteration was fully rescued by re-expression of FoxO1 gene. Compared to the mock cells, loss of FoxO1 reduced the growth rates in the 70Z/3-KD cells, and was fully rescued by reintroduction of FoxO1 gene. The expansion of pre-B cells (CD45R+CD43- fraction) was also reduced by the knockdown of FoxO1 gene. Indeed, FoxO1 induces accumulation in the p27-mediated G0/G1 phase arrest in 70Z/3 cells. FoxO1 bound to the Il7ra locus specifically and regulate the IL-7Rα transcription. In conclusion, FoxO1 regulates the expansion of pre-B cells by regulating the expression of IL-7Rα and its signal transduction.

Forced FoxO1:S249V expression suppressed glioma cell proliferation through G2/M cell cycle arrests and increased apoptosis.

OBJECTIVE: Forkhead box O1 (FoxO1) plays a crucial role in the development of many tumors. Cyclin D kinase (CDK) 1 could influence the nuclear export and activity of FoxO1 through phosphorylation of serine (S)249. However, the effects of S249 phosphorylation in the development of glioma remain unclear. The aim of the present study is to assess the function of FoxO1:S249V mutant, which was converted S249 phosphorylation site into valine (V) residues in the glioma development. METHODS: FoxO1-knockdown U251 glioma cells (U251-KD cells) were established by infection of retrovirus particles with FoxO1 siRNA and FoxO1 restored cells (FoxO1:S249V) were obtained by re-introduction of FoxO1:S249V cDNA. We detected mRNA expression by real-time PCR, and cell cycle arrest and apoptosis by flow cytometric assay, and cell proliferation by BrdU assay and CCK-8 assay. The protective effects of FoxO1:S249V were detected by the xenograft tumor formation assay. RESULTS: The FoxO1 mRNA expression was significantly decreased in the glioma specimens (n = 24). The U251-KD cells showed downregulation of p27 and Bim, while the phosphorylation of CDK1 was upregulated. FoxO1:S249V cells inhibited the phosphorylation of S249, and induced G2/M cell cycle arrest, following reduced cell growth and increased apoptosis. Moreover, FoxO1:S249V expression effectively inhibits the glioma growth. CONCLUSION: Our findings suggest that the forced FoxO1:S249V suppressed the cell growth through G2/M cell cycle arrests and increased apoptosis in glioma.

Alpha thalassemia deletions found in suspected cases of beta thalassemia major in Pakistani population.

BACKGROUND & OBJECTIVE: Alpha (α) thalassemia is a hereditary disorder and is caused by deletions or mutations in globin genes. It is present in two clinically significant forms: hemoglobin Bart hydrops fetalis (Hb Bart) syndrome and hemoglobin H (HbH) disease. It is highly prevalent in South-East Asia or Mediterranean countries. The most common deletion reported in alpha thalassemia in Pakistani population was -α3.7 with a frequency of 8.3%, and the rare forms were -α4.2 (0.2%) and αααanti3.7 (0.9%). In our study, diagnosis of severe anemia cases without any α and ß mutations or deletions were made by using extended alpha thalassemia deletions panel. The main objective of this study was to determine the prevalence and to study the spectra of alpha thalassemia gene deletions in beta thalassemia patients with the use of an extended panel including --SEA, --FIL, --MED, --20.5, --THAI in addition to -α3.7, -α4.2 & -αααanti3.7. METHODS: The samples were collected in ethylenediaminetetraacetic acid (EDTA) vacutainers. A total of 156 samples were analyzed for alpha thalassemia mutations. This cohort included 121 samples of beta thalassemia major, nine samples of beta thalassemia minor and 26 without any evidence of beta thalassemia mutations. DNA was extracted with Qiagen extraction kit. The primers for determination of different subsets of alpha thalassemia deletions were included. PCR amplification was performed and result interpreted on agarose gel. RESULTS: Co-inheritance of alpha thalassemia (-α3.7, -α4.2) with homozygous beta thalassemia was detected in 30% cases of studied cohort (37 out of 121). The most common found was -α3.7 deletion (35/37) as single/double deletions or in combination with -αααanti3.7. In undiagnosed cases screened for beta thalassemia major, we found Mediterranean (-αMED) deletion at specifically 875 bp on agarose gel. This is distinctive finding in case of detecting -αMED instead of any other deletion from Pakistan. CONCLUSION: Alpha thalassemia deletions (-α3.7, -α4.2) are the common co-inherited deletions found in beta thalassemia major patients. On the basis of results, we propose an extended alpha thalassemia genetic mutation panel should be used for screening of children presenting with anemia with suspicion of haemoglobinopathy.

Outcome of Inversion 16 in TKD Positive and Negative Acute Myeloid Leukemia Patients.

abstract.