Cbx4 regulates the proliferation of thymic epithelial cells and thymus function.

Thymic epithelial cells (TECs) are the main component of the thymic stroma, which supports T-cell proliferation and repertoire selection. Here, we demonstrate that Cbx4, a Polycomb protein that is highly expressed in the thymic epithelium, has an essential and non-redundant role in thymic organogenesis. Targeted disruption of Cbx4 causes severe hypoplasia of the fetal thymus as a result of reduced thymocyte proliferation. Cell-specific deletion of Cbx4 shows that the compromised thymopoiesis is rooted in a defective epithelial compartment. Cbx4-deficient TECs exhibit impaired proliferative capacity, and the limited thymic epithelial architecture quickly deteriorates in postnatal mutant mice, leading to an almost complete blockade of T-cell development shortly after birth and markedly reduced peripheral T-cell populations in adult mice. Furthermore, we show that Cbx4 physically interacts and functionally correlates with p63, which is a transcriptional regulator that is proposed to be important for the maintenance of the stemness of epithelial progenitors. Together, these data establish Cbx4 as a crucial regulator for the generation and maintenance of the thymic epithelium and, hence, for thymocyte development.

Id1 expression promotes T regulatory cell differentiation by facilitating TCR costimulation.

T regulatory (Treg) cells play crucial roles in the regulation of cellular immunity. The development of Treg cells depends on signals from TCRs and IL-2Rs and is influenced by a variety of transcription factors. The basic helix-loop-helix proteins are known to influence TCR signaling thresholds. Whether this property impacts Treg differentiation is not understood. In this study, we interrogated the role of basic helix-loop-helix proteins in the production of Treg cells using the CD4 promoter-driven Id1 transgene. We found that Treg cells continued to accumulate as Id1 transgenic mice aged, resulting in a significant increase in Treg cell counts in the thymus as well as in the periphery compared with wild-type controls. Data from mixed bone marrow assays suggest that Id1 acts intrinsically on developing Treg cells. We made a connection between Id1 expression and CD28 costimulatory signaling because Id1 transgene expression facilitated the formation of Treg precursors in CD28(-/-) mice and the in vitro differentiation of Treg cells on thymic dendritic cells despite the blockade of costimulation by anti-CD80/CD86. Id1 expression also allowed in vitro Treg differentiation without anti-CD28 costimulation, which was at least in part due to enhanced production of IL-2. Notably, with full strength of costimulatory signals, however, Id1 expression caused modest but significant suppression of Treg induction. Finally, we demonstrate that Id1 transgenic mice were less susceptible to the induction of experimental autoimmune encephalomyelitis, thus illustrating the impact of Id1-mediated augmentation of Treg cell levels on cellular immunity.

Id1 expression promotes peripheral CD4+ T cell proliferation and survival upon TCR activation without co-stimulation.

Although the role of E proteins in the thymocyte development is well documented, much less is known about their function in peripheral T cells. Here we demonstrated that CD4 promoter-driven transgenic expression of Id1, a naturally occurring dominant-negative inhibitor of E proteins, can substitute for the co-stimulatory signal delivered by CD28 to facilitate the proliferation and survival of naïve CD4+ cells upon anti-CD3 stimulation. We next discovered that IL-2 production and NF-κB activity after anti-CD3 stimulation were significantly elevated in Id1-expressing cells, which may be, at least in part, responsible for the augmentation of their proliferation and survival. Taken together, results from this study suggest an important role of E and Id proteins in peripheral T cell activation. The ability of Id proteins to by-pass co-stimulatory signals to enable T cell activation has significant implications in regulating T cell immunity.

The expression of netrin-1 in the thymus and its effects on thymocyte adhesion and migration.

Netrin-1, a known axon guidance molecule, being a secreted laminin-related molecule, has been suggested to be involved in multiple physiological and pathological conditions, such as organogenesis, angiogenesis, tumorigenesis, and inflammation-mediated tissue injury. However, its function in thymocyte development is still unknown. Here, we demonstrate that Netrin-1 is expressed in mouse thymus tissue and is primarily expressed in thymic stromal cells, and the expression of Netrin-1 in thymocytes can be induced by anti-CD3 antibody or IL-7 treatment. Importantly, Netrin-1 mediates the adhesion of thymocytes, and this effect is comparable to or greater than that of fibronectin. Furthermore, Netrin-1 specifically promotes the chemotaxis of CXCL12. These suggest that Netrin-1 may play an important role in thymocyte development.

[Chinese herbs for shen invigorating and blood activating activated MMP-9 signaling pathway to mobilize rats' bone marrow EPCs: a molecular mechanism research].

OBJECTIVE: To explore the effect of Chinese herbs for Shen invigorating and blood activating (CHSIBA) on the number of endothelial progenitor cells (EPCs) in the bone marrow and the peripheral blood and the signaling pathway of bone marrow matrix metalloproteinase 9 (MMP-9) of the myocardial infarction (MI) model rats. METHODS: The MI rat model was established by ligation. Thirty successfully modeled rats were randomly divided into the high dose CHSIBA group, the low dose CHSIBA group, and the model group, 10 in each group. Besides, another 10 normal rats were recruited as the blank group. Rats in the high dose CHSIBA group and the low dose CHSIBA group were administered with CHSIBA at 3 g/kg and 1.5 g/kg body weight by gastrogavage (by adding them in 4 mL physiological saline), once daily. Rats in the model group and the blank group were administered with 4 mL physiological saline once daily. The EPCs were collected from the bone marrow and the peripheral blood 4 weeks later. Seven days later the CD34/CD133 phenotype was identified in collected sticking wall cells using flow cytometry. The MMP-9 and water soluble Kit ligand (sKitL) were detected using Western blot. The expressions of vascular endothelial growth factor (VEGF) and stromal cell-derived factor-1alpha (SDF-1alpha) were detected using ELISA. RESULTS: The CD34/CD133 positive rate and the EPC quantity in the bone marrow and the peripheral blood were higher in the high dose CHSIBA group and the low dose CHSIBA group than in the model group (P < 0.05, P < 0.01). Besides, the expressions of VEGF, SDF-1alpha, MMP-9, and sKitL in the bone marrow and the peripheral blood were also higher in the high dose CHSIBA group and the low dose CHSIBA group than in the model group (P < 0.05, P < 0.01). CONCLUSION: CHSIBA could activate MMP-9 signaling pathway, increase its upstream and downstream signal expression levels, and mobilize EPCs in the bone marrow to enter the blood circulation.

[Study on effect of backrest thickness to lumbar muscle fatigue during computer work].

OBJECTIVE: To investigate the relationship between backrest thickness and lumbar muscle fatigue so as to confirm the fitting backrest thickness. METHOD: Twenty subjects coming from university seated at a computer workstation in three backrest thicknesses: 4, 7 and 10 cm. The time that the subjects reported the lumbar muscle fatigue was collected during each trial and subjective appraise was collected at the end of the entire protocol. RESULTS: The MF value decreased and lumbar muscle felt fatigue in all three backrest thickness. Subject could feel fatigue more late [(45.0 +/- 10.8) min] and subject felt more comfort at 7 cm thickness. CONCLUSION: It is better to relive computer worker lumbar muscle fatigue when the backrest thickness was kept on 7 cm. Work break was needed because one hour work could cause muscle fatigue.

Antegrade in situ laser fenestration of aortic stent graft during endovascular aortic repair: A case report.

BACKGROUND: The endovascular repair of juxtarenal abdominal aortic aneurysms (JAAA) usually requires combination treatment with various stent graft modifications to preserve side branch patency. As a feasible technique, according to the situation, antegrade in situ laser fenestration still needs to be improved. CASE SUMMARY: This report describes a case that was successfully treated with endovascular repair facilitated by antegrade in situ laser fenestration while maintaining renal arterial flow. Laser fenestration was performed using a steerable sheath positioned in the stent graft lumen in front of the renal artery ostium. With the bare stent region unreleased, renal artery perfusion could be maintained and accurate positioning could be achieved by angiography in real time. CONCLUSION: This study suggests the feasibility and short-term safety of this novel antegrade in situ laser fenestration technique for select JAAA patients.

[Study on IR fingerprint spectra of Alpinia oxyphylla Miq].

Fourier transform infrared spectrum has been developed for application in the quality control of traditional Chinese medicine, and two new indexes, including common peak ratio and variant peak ratio, were applied, and their values were calculated by means of the sequential analysis for eight kinds of essence oil of Alpinia oxyphylla Miq from different cultural areas (Hainan, Guangxi and Guangdong), in which each sample's IR fingerprint spectra were set up and the common peak ratio and variant peak ratio sequences were arranged in the order of size in comparison with other samples. It can be seen that Alpinia oxyphylla samples from Guangxi, Hainan and Guangdong provinces could be successfully revealed directly by the common peak ratio and variant peak ratio sequences. In comparison with their conventional IR spectra, the primary difference in Alpinia oxyphylla is the intensity of characteristic peaks at 1 710 and 1 666 cm(-1). Considering the spectral range of 400-4 000 cm(-1), the common peak ratio of the spectra between Hainan and Guangdong was 62%, while the common peak ratio between Hainan and Guangxi was 52%. But the mix common peak ratio of the spectra in Hainan is 66%. The fingerprint characters of IR can not only identify the main chemical constituents in medicinal materials, but also compare the components differences among the similar samples. The analytical method is an rapid, effective, fast and advanced to evaluate the production area for pharmaceutical market.

[Prokaryotic expression, purification and preparation of polyclonal antibody and immunohistochemistry analysis of RS21-C6 molecule].

OBJECTIVE: To express a thymocyte development related molecule RS21-C6 protein prepare its polyclonal antibodies and study its distribution in thymus by immunohistochemistry analysis. METHODS: RS21-C6 recombinant protein was expressed in E.coli system and then purified by Ni-NTA chromatographic method. Polyclonal antibodies were prepared by immunized rabbits with the purified recombinant protein. Immunohistochemistry analysis was performed to show the distribution of RS21-C6 in mouse thymus tissue. RESULTS: RS21-C6 recombinant protein was successfully expressed and purified. Then the high titer polyclonal antibody was prepared and its specificity was confirmed. The immunohistochemistry analysis demonstrated that RS21-C6 had an intense expression in the medullary region of thymus while scattered in the cortical region and the cortical medullary junction region of thymus. It also showed that RS21-C6 was co-expressed in thymocyte and thymic stromal cells. CONCLUSION: RS21-C6 molecule is broadly and highly expressed in thymus which suggests that this molecule may perform various functions in thymocytes at different developmental stages.