Plasma single-stranded DNA autoantibodies in the diagnosis of Hirschsprung’s disease

Background

Hirschsprung’s disease (HSCR) is a neonatal enteric nervous system (ENS) disease characterized by congenital enteric ganglion cell loss. The only treatment is aganglionic bowel segment resection and innervated bowel segment reconstruction. Delayed diagnosis and treatment cause postoperative complications such as intractable constipation and enterocolitis. Existing preoperative HSCR diagnostic methods have shortcomings such as false positives, radiation and invasiveness.

Methods

We used the robust linear model (RLM) for normalization and the M statistic for screening plasma human autoimmune antigen microarrays and quantitatively assessed single-stranded DNA (ssDNA) antibody levels with enzyme-linked immunosorbent assay (ELISA).

Results

The autoimmune antigen microarray revealed that autoantibodies were higher in HSCR plasma than in disease control (DC) and healthy control (HC) plasma. ssDNA antibodies in HSCR plasma were significantly higher than those in DC and HC plasma. Quantitative ssDNA antibody level detection in plasma by ELISA showed that HSCR (n = 32) was 1.3- and 1.7-fold higher than DC (n = 14) and HC (n = 25), respectively. ssDNA antibodies distinguished HSCR from non-HSCR (HC and DC), achieving an area under the curve (AUC) of 0.917 (95% CI, 0.8550–0.9784), with a sensitivity of 96.99% and a specificity of 74.63%.

Conclusion

ssDNA antibodies in plasma can serve as a diagnostic biomarker for HSCR in the clinic.

Tandem DNAzyme for double digestion: a new tool for circRNA suppression

Circular RNA (circRNA) play a crucial role in many biological processes and have been proved as potential biomarkers and therapeutic targets in many diseases. Manipulation of their expression is a critical task. In this study, we developed a new strategy for circRNA suppression with DNAzyme. Data showed single-digestion DNAzymes cleaved circRNA efficiently in vitro but not in cell culture. However, tandem DNAzymes for double digestion showed higher cleavage efficacy both in vitro and in cell culture. Functional study demonstrated that double-digestion DNAzymes suppressed the miRNA sponge function of circRNA and changed the proliferation and migration rates of HCC cells.

The antihypertensive drug hydralazine activates the intrinsic pathway of apoptosis and causes DNA damage in leukemic T cells

Epigenetic therapies have emerged as promising anticancer approaches, since epigenetic modifications play a major role in tumor initiation and progression. Hydralazine, an approved vasodilator and antihypertensive drug, has been recently shown to act as a DNA methylation inhibitor. Even though hydralazine is already tested in clinical cancer trials, its mechanism of antitumor action remains undefined. Here, we show that hydralazine induced caspase-dependent apoptotic cell death in human p53-mutant leukemic T cells. Moreover, we demonstrate that hydralazine triggered the mitochondrial pathway of apoptosis by inducing Bak activation and loss of the mitochondrial membrane potential. Hydralazine treatment further resulted in the accumulation of reactive oxygen species, whereas a superoxide dismutase mimetic inhibited hydralazine-induced cell death. Interestingly, caspase-9-deficient Jurkat cells or Bcl-2- and Bcl-x_L-overexpressing cells were strongly resistant to hydralazine treatment, thereby demonstrating the dependence of hydralazine-induced apoptosis on the mitochondrial death pathway. Furthermore, we demonstrate that hydralazine treatment triggered DNA damage which might contribute to its antitumor effect.

Hypotheses of the origin of natural antibodies: a glycobiologist's opinion

It is generally accepted that the generation of antibodies proceeds due to immunization of an organism by alien antigens, and the level and affinity of antibodies are directly correlated to the presence of immunogen. At the same time, vast experimental material has been obtained providing evidence of antibodies whose level remains unchanged and affinity is constant during a lifetime. In contrast to the first, adaptive immunoglobulins, the latter are named natural antibodies (nAbs). The nAbs are produced by B1 cells, whereas adaptive Abs are produced by B2. This review summarizes general data on nAbs and presents in more detail data on antigens of carbohydrate origin. Hypotheses on the origin of nAbs and their activation mechanisms are discussed. We present our thoughts on this matter supported by our experimental data on nAbs to glycans.