CRH knockout inhibits the murine innate immune responses in association with endoplasmic reticulum stress after thermal injury

Kinetics of Inflammatory Mediators in the Immune Response to Burn Injury: Systematic Review and Meta-Analysis of Animal Studies

Burns are often accompanied by a dysfunctional immune response, which can lead to systemic inflammation, shock, and excessive scarring. The objective of this study was to provide insight into inflammatory pathways associated with burn-related complications. Because detailed information on the various inflammatory mediators is scattered over individual studies, we systematically reviewed animal experimental data for all reported inflammatory mediators. Meta-analyses of 352 studies revealed a strong increase in cytokines, chemokines, and growth factors, particularly 19 mediators in blood and 12 in burn tissue. Temporal kinetics showed long-lasting surges of proinflammatory cytokines in blood and burn tissue. Significant time-dependent effects were seen for IL-1β, IL-6, TGF-β1, and CCL2. The response of anti-inflammatory mediators was limited. Burn technique had a profound impact on systemic response levels. Large burn size and scalds further increased systemic, but not local inflammation. Animal characteristics greatly affected inflammation, for example, IL-1β, IL-6, and TNF-α levels were highest in young, male rats. Time-dependent effects and dissimilarities in response demonstrate the importance of appropriate study design. Collectively, this review presents a general overview of the burn-induced immune response exposing inflammatory pathways that could be targeted through immunotherapy for burn patients and provides guidance for experimental set-ups to advance burn research.

Proteomic analysis of hemocyte reveals the immune regulatory mechanisms after the injection of corticosteroid-releasing hormone in mud crab Scylla Paramamosain

Corticosteroid-releasing hormone (CRH) is a crucial neuroendocrine-immune factor regulating the immune response of Scylla paramamosain. To understand the regulatory mechanisms of CRH in S. paramamosain, the hemolymph of S. paramamosain with injection of CRH (1.5 ng/crab) at 24 h were chosen to perform proteomic analysis in this study. Furthermore, quantitative real-time PCR (RT-PCR) method was used to validate the accuracy of proteomic data at 24 h after CRH injection. The proteomic data showed that 255 DEPs were identified, in which 231 and 24 were up- or down-regulated, respectively. Besides, the results of enriched pathways showed that the DEPs were involved in signaling pathways, cellular immunity, humoral immunity and the response of immune related processes. These results revealed that CRH promoted the activation of signal transduction, regulated immune systems and antioxidation, and enhanced the immune related processes (such as protein synthesis, protein transport, carbohydrate mobilization and energy redistribution). These findings will benefit to foster the understanding on the effects of glucocorticoids on neuroendocrine-immune (NEI) networks of crustacean, and supply a substantial material and foundation for further researching of the NEI response. SIGNIFICANCE: Corticotrophin-releasing hormone (CRH) is a 41-amino acid neuropeptide and has been preliminarily studied in aquatic animals. CRH can regulate many important physiological activities comprising protein synthesis, energy metabolism, growth, breeding and behavior in fish, which play an important roles in neuroendocrine-immune (NEI) regulatory network of fish. The neuroendocrine system of crustacean has a primary research, that inspired by fish NEI network. Despite the research on the neuroendocrine system in crustacean has rapidly increased in recent years, our understanding of the regulation between neuroendocrine system and immune system in crustacean is still limited. The research on the strategy of NEI network in crustaceans becomes a significant issue. In the present study, the isobaric tags for relative and absolute quantification (iTRAQ) technology approach were applied to examine the NEI network of Scylla Paramamosain. control group and treatment group (CRH: 1.5 ng/crab) were settled for the iTRAQ experiment, and sampled at 24 h after CRH injection. The study aimed to gain knowledge on the immune response in Scylla Paramamosain after CRH injection and identify related differentially expressed proteins (DEPs) of the crab. The results of this study provide a preliminary resource for analysis the immune mechanism for crustaceans. In general, our work represents the first report of the utilization of the iTRAQ proteomics method for the study of NEI regulatory network in Scylla Paramamosain after CRH injection. We identified a number of DEPs involved in diverse pathways including immune signaling pathways, cellular immunity, humoral immunity, immune related process. These results demonstrated a very complex network involving immune and multiple related metabolic pathways in hemocytes of Scylla Paramamosain and will be of great value in understanding the crab neuroendocrine-immune immune mechanism.

Glucocorticoid guides mobilization of bone marrow stem/progenitor cells via FPR and CXCR4 coupling

Background

Our previous studies have proved the efficient exogenous repairing responses via bone marrow stem and progenitor cells (BMSPCs). However, the trafficking of endogenous bone marrow stem and progenitor cells to and from the bone marrow (BM) is a highly regulated process that remains to be elucidated. We aimed to study the relative importance of the hypothalamic-pituitary-adrenal (HPA) axis in the glucocorticoid-induced BMSPC mobilization.

Methods

The circulating mesenchymal stem cells (MSCs) and endothelial progenitor cells (EPCs) were examined in Crh (+/+, −/−) mice after running stress or glucocorticoid mini-infusion. The MSCs and EPCs were investigated ex vivo after treatment with glucocorticoid and glucocorticoid receptor (GR) antagonist, RU486. The expression of chemotaxis receptors, N-formyl peptide receptor (FPR), and Cys-X-Cys receptor 4 (CXCR4) of MSCs and EPCs as well as their colocalization were investigated after treatment with glucocorticoid, glucocorticoid receptor (GR) antagonist (RU486), and FPR antagonist (Cyclosporin H).

Results

Forced running stress increased circulating MSCs and EPCs in mice, which was blunted when Crh was knocked out, and positively related to the levels of serum glucocorticoid. Prolonged glucocorticoid mini-infusion imitated the stress-induced increase in circulating MSCs and EPCs in Crh^+/+ mice and rescued the impaired mobilization in circulating MSCs and EPCs in Crh^−/− mice. Meanwhile, glucocorticoid promoted the chemotaxis of MSCs and EPCs ex vivo via GR, inhibited by RU486 (10 μM). Concurrently, glucocorticoid increased the expression of FPR of MSCs and EPCs, but inhibited their expression of CXCR4, followed by their changing colocalization in the cytoplasm. The GC-induced colocalization of FPR and CXCR4 was blunted by Cyclosporin H (1 μM).

Conclusion

Glucocorticoid-induced CXCR4-FPR responsiveness selectively guides the mobilization of BMSPCs, which is essential to functional tissue repair.

Graphical abstract

Schematic view of the role of glucocorticoid on the mobilization of bone marrow-derived stem/progenitor cells subsets in the present study. The HPA axis activation promotes the release of glucocorticoid, which regulates the directional migration of MSCs and EPCs mainly via GR. The possible mechanisms refer to the signal coupling of FPR and CXCR4. Their two-sided changes regulated by glucocorticoid are involved in the egress of MSCs and EPCs from BM, which is helpful for wound healing. MSCs, mesenchymal stem cells; EPCs, endothelial progenitor cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-020-02071-1.

Altered Neuroendocrine Immune Responses, a Two-Sword Weapon against Traumatic Inflammation

During the occurrence and development of injury (trauma, hemorrhagic shock, ischemia and hypoxia), the neuroendocrine and immune system act as a prominent navigation leader and possess an inter-system crosstalk between the reciprocal information dissemination. The fundamental reason that neuroendocrinology and immunology could mix each other and permeate toward the field of traumatology is owing to their same biological languages or chemical information molecules (hormones, neurotransmitters, neuropeptides, cytokines and their corresponding receptors) shared by the neuroendocrine and immune systems. The immune system is not only modulated by the neuroendocrine system, but also can modulate the biological functions of the neuroendocrine system. The interactive linkage of these three systems precipitates the complicated space-time patterns for the courses of traumatic inflammation. Recently, compelling evidence indicates that the network linkage pattern that initiating agents of neuroendocrine responses, regulatory elements of immune cells and effecter targets for immune regulatory molecules arouse the resistance mechanism disorders, which supplies the beneficial enlightenment for the diagnosis and therapy of traumatic complications from the view of translational medicine. Here we review the alternative protective and detrimental roles as well as possible mechanisms of the neuroendocrine immune responses in traumatic inflammation.