Direct measurement of B-cell receptor repertoire's composition and variation in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease that is known to be associated with polyclonal B-cell hyper-reactivity. B-cell receptor (BCR) has a central role in B-cell development, activation, survival and apoptosis, and thus is a critical component of the regulation of both protective and autoreactive B cells. In this study, we applied multiplex PCR and Illumina high-throughput sequencing to study the composition and variation of the BCRs in peripheral blood mononuclear cells from SLE patients and healthy donors (NC). We found that SLE group displayed significantly shorter CDR3 average length (14.86±0.76aa vs 15.70±0.43aa), more arginine percentage of CDR3 amino acids (7.57±0.20% vs 7.32±0.19%) and poorer immunological diversity than the healthy ones. CDR3 sequence YGMDV present in all SLE samples may provide more information in generating more effective B-cell targeted diagnosis/therapies strategies.

[Carpal canal ultrasound examination in patients with mild hand-arm vibration disease]

Objective: To investigate the clinical value of ultrasound examination of carpal canal structure in patients with mild hand-arm vibration disease. Methods: A total of 29 patients (58 wrists) with mild hand-arm vibration disease who were treated in Shenzhen Prevention and Treatment Center for Occupational Diseases from May to December, 2015 were enrolled as observation group, and 20 healthy volunteers (40 wrists) were enrolled as the control group. Color Doppler ultrasound was used to observe the morphology and echo of the median nerve in the carpal canal and 9 muscle tendons and transverse carpal ligament. The thickness of transverse carpal ligament and diameter of the median nerve at the level of the hamulus of hamate bone were measured, as well as the cross-sectional area of the median nerve at the level of pisiform bone. Results: In the 29 patients with hand-arm vibration disease patients in the observation group, 8 experienced entrapment of the median nerve in the carpal canal, among whom 5 had entrapment in both wrists; there were 13 wrists (23%) with nerve entrapment and 45 wrists (77%) without nerve entrapment. Compared with the control group, the patients with hand-arm vibration disease and nerve entrapment in the observation group showed significant thickening of the transverse carpal ligament at the level of the hamulus of hamate bone and a significant increase in the cross-sectional area of the median nerve at the level of pisiform bone (P<0.05) , while there were no significant differences in the thickness of transverse carpal ligament at the level of the hamulus of hamate bone and the cross-sectional area of the median nerve at the level of pisiform bone (t=-9.397 and -4.385, both P>0.05) . Conclusion: Ultrasound examination can clearly show the radiological changes of carpal canal contents in patients with mild hand-arm vibration disease and has a certain diagnostic value in nerve damage in patients with hand-arm vibration disease.

DNA hypermethylation of the forkhead box protein 3 (FOXP3) promoter in CD4+ T cells of patients with systemic sclerosis

BACKGROUND

Systemic sclerosis (SSc) is a complex autoimmune disease that involves dysregulation of immune homeostasis. The failure of impaired regulatory T cells (Tregs) to maintain immune homeostasis plays a major role in the development of SSc. Transcriptional silencing of the forkhead box protein 3 gene (FOXP3) via hypermethylation of regulatory regions has been identified as a hallmark of committed Tregs and several autoimmune disorders.

OBJECTIVES

To investigate whether aberrant expression and methylation of FOXP3 occurs in CD4+ T cells of patients with SSc and their roles in the pathogenesis of SSc.

METHODS

FOXP3 expression in CD4+ T cells was measured by real-time quantitative reverse-itranscriptase polymerase chain reaction and western blot. Bisulfite sequencing was performed to determine the methylation status of the FOXP3 proximal promoter sequence. The percentage of Treg cells was estimated by flow cytometry.

RESULTS

Decreased FOXP3 expression was observed in CD4+ T cells from patients with SSc. The methylation levels of the FOXP3 regulatory sequences were elevated and inversely correlated with FOXP3 mRNA expression in patients with SSc. The number of Tregs was significantly reduced in patients with SSc. Treatment of SSc CD4+ T cells with a DNA methylation inhibitor, 5-azacytidine, reduced the mean methylation levels, and enhanced FOXP3 expression and Treg generation. The promoter methylation status and expression level of FOXP3 are significantly associated with disease activity.

CONCLUSIONS

The contribution of the hypermethylation of the FOXP3 promoter to decreased FOXP3 expression and the subsequent quantitative defects of Tregs may mediate the immune dysfunction in SSc.

Down-regulation of mitochondrial ATPase by hypermethylation mechanism in chronic myeloid leukemia is associated with multidrug resistance

BACKGROUND

To identify novel proteins involved in multidrug resistance in chronic myeloid leukemia (CML).

MATERIALS AND METHODS

Comparative proteomics was used to screen multidrug resistance-related proteins from K562 and K562/A02; the differently expressed proteins were further confirmed by western blot and real-time PCR. short hairpin RNA (shRNA) assay was applied to determine the relationship between candidate protein and adriamycin resistance. Bisulfite sequencing was carried out to assess methylation status of candidate multidrug resistance-related gene promoter. K562/A02 was treated with 5-azacytidine or trichostatin A (TSA); multidrug resistance phenotype and corresponding protein or gene changes were detected.

RESULTS

Seventeen proteins with altered abundances of more than twofold were detected, among which mitochondrial ATPase in K562/A02 was significantly down-regulated. Suppressing mitochondrial ATPase by shRNA could enhance adriamycin resistance and antiapoptosis activity of K562. The promoter hypermethylation in mitochondrial ATPase was found to be attributed to the adriamycin-resistant phenotype of both K562/A02 (methylated frequency 18.18%) and CML primary cells in accelerated phase (methylated frequency 7.95%) or blast crisis (methylated frequency 26.59%). Inhibition of hypermethylation increased adriamycin sensitivity of K562/A02. A synergistic effect on reversing adriamycin-resistant phenotype was obtained when 5-azacytidine was combined with TSA.

CONCLUSION

Down-regulation of mitochondrial ATPase can lead to adriamycin resistance in CML and the mechanism is associated with DNA methylation regulation.

[Construction of recombinant antisense RNA IgG2aVH region of murine systemic lupus erythematous]

OBJECTIVE

To construct recombinant plasmid of IgG2aVH region antisense RNA of systemic lupus erythematous.

METHODS

Total RNA was isolated from spleen cell of BWF1 mice. Using spleen cell total RNA as the template, We designed specific primers from A6.1 region sequences, and amplified the IgG2aVH region 375 bp DNA fragments by RT-PCR. The IgG2aVH cDNA was cloned by T/A and inserted into pcDNA 3.1 plasmid of vector.

RESULTS

The IgG2aVH antisense RNA plasmid expressing recombinant was identified by restriction enzyme digestion and DNA sequence analysis.

CONCLUSION

There is IgG2aVH gene in F1 mice spleen cell; the IgG2aVH antisense RNA expressing recombinants is constructed successfully.

[Establishment and its application of a reporter-based screening model for discovering new ligands of estrogen receptor alpha subtypes]

AIM

To establish a sensitive and efficient reporter gene based screening model and use it to screen compounds for discovering new ligands of estrogen receptor alpha subtype.

METHODS

A recombinant Epstein-Barr virus episomal vector (pMT/ERE-CAT) was constructed by inserting a synthetic sequence composed of five estrogen response elements upstream of promoter and a chloramphenicol acetyltransferase (CAT) gene downstream of promoter. pMT/ERE-CAT was transfected into HepG2 cells expressing estrogen receptor alpha subtype (ER +HepG2). Hygromycin (200 micrograms.mL-1) was added 48 h after transfection for selection. One stably transfected clone was isolated and used to screen compounds for activity of stimulating CAT gene expression using colorimetric CAT assay.

RESULTS

In the ER +HepG2 cells, the expression of CAT gene was induced by estradiol. A dose-dependent expression of CAT gene with half-maximal induction at 0.07 nmol.L-1 was observed. The ER +HepG2 cell was used to screen compounds for activity of stimulating CAT gene expression. Resveratrol was found to produce a maximal level of induction (1.75 times of estradiol). In vitro radiation survival experiment showed that the radioprotection activity of resveratrol (D0 = 3.18 Gy) is stronger than that of estradiol (D0 = 2.59 Gy).

CONCLUSION

Vector pMT/ERE-CAT was used to generate stably transfected ER +HepG2 cell lines. The cell lines can be used to screen compounds for estrogen activity by testing extracts of cells grown in microtiter wells directly using colorimetric CAT assay. This system should provide an efficient method for screening and analyzing the activity of large numbers of ligands of estrogen receptor.