CD4(+) T cells from food allergy model are resistant to TCR-dependent apoptotic induction

Endoplasmic Reticulum Stress Promotes Telomerase Reverse Transcriptase Expression Contributes to Development of Allergic Rhinitis

BACKGROUND

The Th2 cell polarization is a crucial factor in the pathogenesis of allergic diseases. The underlying mechanism requires further investigation. Telomerase has an immune-regulating ability. The aim of this study is to elucidate the association between telomerase and Th2 cell polarization in patients with allergic rhinitis (AR).

METHODS

CD4+ T cells were isolated from blood samples collected from AR patients and healthy control subjects. RNA sequencing was employed to analyze RNA samples extracted from CD4+ T cells. An AR mouse model was established using the ovalbumin-alum protocol.

RESULTS

High telomerase gene activity and high endoplasmic reticulum (ER) stress status were observed in CD4+ T-cells in patients with AR. Positive correlation between the telomerase reverse transcriptase (TERT) gene expression in CD4+ T cells and AR response in patients with AR. TERT facilitated the degradation of Foxp3 proteins in CD4+ T cells, resulting in the polarization of Th2 cells. Sensitization with the ovalbumin-alum protocol enhanced the Tert expression in CD4+ T cells by exacerbating ER stress. Conditional inhibition of the Tert or eukaryotic translation initiation factor 2-α (Eif2a) expression in CD4+ T cells effectively attenuated experimental AR in mice.

CONCLUSIONS

Elevated amounts of telomerase in CD4+ T cells were found in CD4+ T cells of subjects with AR. Telomerase promoted Th2 cell polarization by inducing Foxp3 protein degradation and promotes GATA3 activation. Inhibition of TERT or eIF2a alleviated experimental AR.

Regulation of Tert methylation alleviates food allergy via regulating the Tert-IL10 signal pathway

BACKGROUND

The cause of food allergy (FA) is still a mystery. Telomerases are involved in the regulation of immune responses. This study aims to gain an understanding of the contribution of telomerase reverse transcriptase (TERT) to the pathogenesis of FA.

METHODS

A murine FA model was established with ovalbumin as the specific antigen. The role of TERT in regulating dendritic cell (DC) immune tolerogenic functions was evaluated in this murine model.

RESULTS

We observed that the Tert promoter was at demethylation status and the Tert expression was elevated in DCs of FA mice. The Tert expression in DCs had a positive correlation with the FA response. TERT prevented the induction of Il10 expression in DCs. The immune tolerogenic functions of DCs were diminished by TERT. The immune tolerogenic functions of DC were restored by CpG by boosting the Tert promoter methylation. Administration of CpG promoted the therapeutic effects of allergen specific immunotherapy in FA mice.

CONCLUSIONS

Low levels of Il10 expression and high levels of Tert expression were observed in intestinal DCs of FA mice. CpG exposure restored the expression of Il10 and increased the therapeutic benefits of allergen-specific immunotherapy.

Restoration of Mal overcomes the defects of apoptosis in lung cancer cells

BACKGROUND AND AIMS

Cancer is one of the life-threatening diseases of human beings; the pathogenesis of cancer remains to be further investigated. Toll like receptor (TLR) activities are involved in the apoptosis regulation. This study aims to elucidate the role of Mal (MyD88-adapter-like) molecule in the apoptosis regulation of lung cancer (LC) cells.

METHODS

The LC tissues were collected from LC patients. LC cells and normal control (NC) cells were isolated from the tissues and analyzed by pertinent biochemical and immunological approaches.

RESULTS

We found that fewer apoptotic LC cells were induced by cisplatin in the culture as compared to NC cells. The expression of Fas ligand (FasL) was lower in LC cells than that in NC cells. FasL mRNA levels declined spontaneously in LC cells. A complex of FasL/TDP-43 was detected in LC cells. LC cells expressed less Mal than NC cells. Activation of Mal by lipopolysaccharide (LPS) increased TDP-43 expression in LC cells. TDP-43 formed a complex with FasL mRNA to prevent FasL mRNA from decay. Reconstitution of Mal or TDP-43 restored the sensitiveness of LC cells to apoptotic inducers.

CONCLUSIONS

LC cells express low Mal levels that contributes to FasL mRNA decay through impairing TDP-43 expression. Reconstitution of Mal restores sensitiveness of LC cells to apoptosis inducers that may be a novel therapeutic approach for LC treatment.

Regulating Bcl2L12 expression in mast cells inhibits food allergy

Rationale: Mast cells play a crucial role in allergic diseases. Yet, the regulation of mast cell bioactivities is not fully understood. This study aims to elucidate the role of B cell lymphoma 2 like protein 12 (Bcl2L12), one of the anti-apoptosis proteins, in regulating mast cell apoptosis.

Methods: A food allergy (FA) mouse model was developed to establish mast cell over population in the intestinal tissue. Either compound 48/80 (C48/80) or specific antigens were used to activate mast cells in the intestinal mucosa.

Results: After treating with C48/80, apoptosis was induced in mast cells of the intestine of naive control mice, but not in FA mice. The expression of Fas ligand (FasL) was lower in the mast cells of FA mice. Interleukin (IL)-5 was responsible for the suppression of FasL by upregulating the expression of Bcl2L12 in mast cells. Bcl2L12 prevented c-Myc, the major transcription factor of FasL, from binding the FasL promoter to inhibit the expression of FasL in mast cells. Inhibition of Bcl2L12 restored the apoptosis machinery of mast cells in the FA mouse intestine.

Conclusions: The apoptosis machinery in mast cells is impaired in an allergic environment. Inhibition of Bcl2L12 restores the apoptosis machinery in mast cells in the FA mouse intestine.

The Implications of DNA Methylation on Food Allergy

Food allergy is a major clinical and public health concern worldwide. The risk factors are well defined, however, the mechanisms by which they affect immune development remain largely unknown, and unfortunately the effective treatment or prevention of food allergy is still being researched. Recent studies show that the genes that are critical for the development of food allergy are regulated through DNA methylation. Environmental factors can affect host DNA methylation status and subsequently predispose people to food allergy. DNA methylation is therefore an important mediator of gene-environment interactions in food allergy and key to understanding the mechanisms underlying the allergic development. Indeed, the modification and identification of the methylation levels of specific genetic loci have gained increasing attention for therapeutic and diagnostic application in combating food allergy. In this review, we summarize and discuss the recent developments of DNA methylation in food allergy, including the pathogenesis, therapy, and diagnosis. This review will also summarize and discuss the environmental factors that affect DNA methylation levels in food allergy.

Tumor-specific Th2 responses inhibit growth of CT26 colon-cancer cells in mice via converting intratumor regulatory T cells to Th9 cells

The abnormality of immune regulation plays a critical role in the pathogenesis of cancer; the underlying mechanism has not been fully understood yet. This study aims to investigate the role of cancer specific T helper (Th)2 response in the inhibition of colon cancer (Cca) cell growth. The results showed that with Cca cell (CT26 cell) extracts as an antigen, the Cca-extract specific Th2 response was induced in the Cca-bearing mice. The Cca mass size was significantly reduced, or radically disappeared (5 out of 10; or 50%); the survival rate was markedly improved in mice immunized with Cca-extract, but not in those immunized with another tumor cell (U87 cell) extracts or to bovine serum albumin. The immunization with Cca-extract also induced Cca cell apoptosis and converted the intra-Cca Tregs to T helper (Th) 9 cells. In conclusion, Cca-specific Th2 responses inhibit Cca growth in a mouse model via inducing Cca cell apoptosis and converting intra-Cca Tregs to Th9 cells.