β-arrestin 2-mediated immune suppression induced by chronic stress

β-Arrestin 2 acts an adaptor protein that facilitates viral replication in silkworm

β-Arrestin 2 is known to be a widely distributed adaptor protein in mammals but its function has never been reported in Lepidoptera insects. Herein, the β-Arrestin 2 (BmArrestin 2) gene from silkworm was cloned and characterized. The spatiotemporal expression level of BmArrestin 2 was highest in the gonads at the 3rd day of 5th instar, whereas the highest and lowest abundance of BmArrestin 2 were identified in the tracheal and testis, respectively. BmArrestin 2 is mainly distributed in the cytoplasm. Furthermore, in BmN cells，overexpression of BmArrestin 2 promoted Bombyx mori nucleopolyhedrovirus (BmNPV) and B. mori cytoplasmic polyhedrosis virus (BmCPV) replication as the increment of the concentration of plasmid transfection, whereas silencing the gene with specific siRNA inhibited viral replication. Replication of BmNPV and BmCPV also was weakened using BmArrestin 2 antiserum as the increment of the concentration. Immunofluorescent staining revealed the invasion of recombinant BmNPV or BmCPV was decreased after blocking endogenous BmArrestin 2. On the other hand, BmArrestin 2 co-localizes with recombinant BmNPV and BmCPV virions in BmN cells. These results suggest that BmArrestin 2 may represent a novel target for antiviral strategies, as it is an adaptor protein that plays a key role in virus replication.

Deficiency of β-arrestin2 exacerbates inflammatory arthritis by facilitating plasma cell formation

β-arrestin2 (β-arr2) is, a key protein that mediates desensitization and internalization of G protein-coupled receptors and participates in inflammatory and immune responses. Deficiency of β-arr2 has been found to exacerbate collagen antibody-induced arthritis (CAIA) through unclear mechanisms. In this study we tried to elucidate the molecular mechanisms underlying β-arr2 depletion-induced exacerbation of CAIA. CAIA was induced in β-arr2-/- and wild-type (WT) mice by injection of collagen antibodies and LPS. The mice were sacrificed on d 13 after the injection, spleen, thymus and left ankle joints were collected for analysis. Arthritis index (AI) was evaluated every day or every 2 days. We showed that β-arr2-/- mice with CAIA had a further increase in the percentage of plasma cells in spleen as compared with WT mice with CAIA, which was in accordance with elevated serum IgG1 and IgG2A expression and aggravating clinical performances, pathologic changes in joints and spleen, joint effusion, and joint blood flow. Both LPS stimulation of isolated B lymphocytes in vitro and TNP-LPS challenge in vivo led to significantly higher plasma cell formation and antibodies production in β-arr2-/- mice as compared with WT mice. LPS treatment induced membrane distribution of toll-like receptor 4 (TLR4) on B lymphocytes, accordingly promoted the nuclear translocation of NF-κB and the transcription of Blimp1. Immunofluorescence analysis confirmed that more TLR4 colocalized with β-arr2 in B lymphocytes in response to LPS stimulation. Depletion of β-arr2 restrained TLR4 on B lymphocyte membrane after LPS treatment and further enhanced downstream NF-κB signaling leading to additional increment in plasma cell formation. In summary, β-arr2 depletion exacerbates CAIA and further increases plasma cell differentiation and antibody production through inhibiting TLR4 endocytosis and aggravating NF-κB signaling.

Effect of rapamycin on repeated immobilization stress-induced immune alterations in the rat spleen

Chronic stress modulates immune system functions via neuroendocrine pathways. Rapamycin inhibits activity of immune cells through the mTOR signaling pathway. We investigated the effect of rapamycin (15 mg/kg, 3-times/week) on neuroimmune-endocrine system in the spleen of rats exposed to 42 cycles of 2-h immobilization. Rapamycin enhanced the activity of hypothalamic-pituitary-adrenocortical axis induced by stress exposure, prevented stress-induced expression of natural killer cell markers while reversed stress-evoked decline of Th2 immune response markers. Overall, our findings suggest that rapamycin may act on immune functions not only directly by inhibiting of mTOR in immune cells but also indirectly via modulation of neuroendocrine system.

Perceived Age and Life Style. The Specific Contributions of Seven Factors Involved in Health and Beauty

OBJECTIVES

The skin is a dynamic, visible organ, showing the most obvious signs of aging. The mechanisms of extrinsic aging, most of them presented in this paper, are currently well known and also the only ones that can be counteracted. Therefore, the transition of this knowledge in the general population is of the most importance, in order to introduce healthy aging strategies, to prevent the development of chronic or malignant diseases and psychological burden related to old age.

MATERIALS AND METHODS

A thorough review of the literature has been performed in order to identify the main factors involved in skin health and aging.

OUTCOMES

This concept article represents a compilation of seven anti-ageing directions regarding major factors involved in health, aging and beauty, respectively sun, sugar, smoking, skin care, stress, sleep and second (the passage of time), easy to comprehend by the general public but sustained by a strong scientific documentation.

CONCLUSIONS

Despite its final destination, every quality concept has to pass through academic purgatory as, once accepted, it comes to respond to ever more educated society's demands in terms of anti-ageing.

Hematopoietic stem progenitor cells prevent chronic stress-induced lymphocyte apoptosis

Physical or psychological chronic stress can suppress the immune system. However, the mechanisms remain to be elucidated. We investigated the effect of hematopoietic stem-progenitor cells (HSPCs) on chronic stress-induced the alterations of immune responses. We demonstrate that HSPCs prevents stress-induced lymphocyte apoptosis. Moreover, we also demonstrate that the protective effect of HSPCs on stress-induced lymphocyte reduction exerts by steroid hormones. Furthermore, we reveal that chronic stress-induced T cell-mediated immune responses contributes to the protective effect of HSPCs. These results indicate that HPSCs might offer a novel therapeutic strategy against the deleterious effects of chronic stress on the immune system.

Epigenetic response in mice mastitis: Role of histone H3 acetylation and microRNA(s) in the regulation of host inflammatory gene expression during Staphylococcus aureus infection

Background

There is renewed interest towards understanding the host-pathogen interaction in the light of epigenetic modifications. Although epithelial tissue is the major site for host-pathogen interactions, there is handful of studies to show how epithelial cells respond to pathogens. Bacterial infection in the mammary gland parenchyma induces local and subsequently systemic inflammation that results in a complex disease called mastitis. Globally Staphylococcus aureus is the single largest mastitis pathogen and the infection can ultimately result in either subclinical or chronic and sometimes lifelong infection.

Results

In the present report we have addressed the differential inflammatory response in mice mammary tissue during intramammary infection and the altered epigenetic context induced by two closely related strains of S. aureus, isolated from field samples. Immunohistochemical and immunoblotting analysis showed strain specific hyperacetylation at histone H3K9 and H3K14 residues. Global gene expression analysis in S. aureus infected mice mammary tissue revealed a selective set of upregulated genes that significantly correlated with the promoter specific, histone H3K14 acetylation. Furthermore, we have identified several differentially expressed known miRNAs and 3 novel miRNAs in S. aureus infected mice mammary tissue by small RNA sequencing. By employing these gene expression data, an attempt has been made to delineate the gene regulatory networks in the strain specific inflammatory response. Apparently, one of the isolates of S. aureus activated the NF-κB signaling leading to drastic inflammatory response and induction of immune surveillance, which could possibly lead to rapid clearance of the pathogen. The other strain repressed most of the inflammatory response, which might help in its sustenance in the host tissue.

Conclusion

Taken together, our studies shed substantial lights to understand the mechanisms of strain specific differential inflammatory response to S. aureus infection during mastitis. In a broader perspective this study also paves the way to understand how certain bacteria can evade the immune surveillance and cause sustained infection while others are rapidly cleared from the host body.

Toll-like receptor 9 is required for chronic stress-induced immune suppression

OBJECTIVES

Mental and physical stress can suppress the immune system in both humans and animals. The mechanism by which stress affects immune responses, however, remains poorly defined. Toll-like receptors (TLRs) play a key role in modulating immune responses and cell survival. The mechanisms by which TLRs modulate chronic stress are largely unexplored.

METHODS

Six- to 8-week-old male mice were subjected to chronic 12-hour daily physical restraint stress. Apoptotic cells were determined by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) assay. We examined cytokine levels by enzyme-linked immunosorbent Assay (ELISA). The expression of CYP11A1 was determined by quantitative real-time RT-PCR.

RESULTS

TLR9-deficient mice were resistant to chronic stress-induced lymphocyte apoptosis. In addition, in TLR9 knockout (KO) mice, chronic stress-induced upregulation of corticosterone levels was significantly decreased. Notably, lymphocytes from both TLR9 KO and wild-type mice were similarly sensitive to corticosteroid-induced cell apoptosis. Moreover, TLR9 deficiency blocked the chronic stress-induced imbalance in T helper (Th) 1 and Th2 cytokine levels.

CONCLUSION

Taken together, our findings reveal that TLR9 plays an essential role in chronic stress-induced immune suppression.

β-Arrestins in the immune system

β-Arrestins regulate G protein-coupled receptors through receptor desensitization while also acting as signaling scaffolds to facilitate numerous effector pathways. Recent studies have provided evidence that β-arrestins play a key role in inflammatory responses. Here, we summarize these advances on the roles of β-arrestins in immune regulation and inflammatory responses under physiological and pathological conditions, with an emphasis on translational implications of β-arrestins on human diseases.