Psychological stress increases the risk of gastrointestinal (GI) tract diseases, which involve bidirectional communication of the GI and nerves systems. Acute stress leads to GI ulcers; however, the mechanism of the native cellular protection pathway, which safeguards tissue integrality and maintains GI homeostasis, remains to be investigated. In a mouse model of this study, restraint stress induced GI leakage, abnormal tight junction protein expression, and cell death of gut epithelial cells. The expression of activating transcription factor 3 (ATF3), a stress-responsive transcription factor, is upregulated in the GI tissues of stressed animals. ATF3-deficient mice displayed an exacerbated phenotype of GI injuries. These results suggested that, in response to stress, ATF3 is part of the native cellular protective pathway in the GI system, which could be a molecular target for managing psychological stress-induced GI tract diseases.

Background: Lethal toxin (LT) is a major virulence factor of Bacillus anthracis. Sprague Dawley rats manifest pronounced lung edema and shock after LT treatments, resulting in high mortality. The heart failure that is induced by LT has been suggested to be a principal mechanism of lung edema and mortality in rodents. Since LT-induced death occurs more rapidly in rats than in mice, suggesting that other mechanisms in addition to the heart dysfunction may be contributed to the fast progression of LT-induced pathogenesis in rats. Coagulopathy may contribute to circulatory failure and lung injury. However, the effect of LT on coagulation-induced lung dysfunction is unclear. Methods: To investigate the involvement of coagulopathy in LT-mediated pathogenesis, the mortality, lung histology and coagulant levels of LT-treated rats were examined. The effects of activated protein C (aPC) on LT-mediated pathogenesis were also evaluated. Results: Fibrin depositions were detected in the lungs of LT-treated rats, indicating that coagulation was activated. Increased levels of plasma D-dimer and thrombomodulin, and the ameliorative effect of aPC further suggested that the activation of coagulation-fibrinolysis pathways plays a role in LT-mediated pathogenesis in rats. Reduced mortality was associated with decreased plasma levels of D-dimer and thrombomodulin following aPC treatments in rats with LT-mediated pathogenesis. Conclusions: These findings suggest that the activation of coagulation in lung tissue contributes to mortality in LT-mediated pathogenesis in rats. In addition, anticoagulant aPC may help to develop a feasible therapeutic strategy.

Red blood cells are the most abundant cells in the blood that deliver oxygen to the whole body. Erythropoietin (EPO), a positive regulator of erythropoiesis, is currently the major treatment for chronic anemia. Granulocyte colony-stimulating factor (G-CSF) is a multifunctional cytokine and a well-known regulator of hematopoietic stem cell proliferation, differentiation, and mobilization. The use of EPO in combination with G-CSF has been reported to synergistically improve erythroid responses in a group of patients with myelodysplastic syndromes who did not respond to EPO treatment alone; however, the mechanism remains unclear. C57BL/6 J mice injected with G-CSF or EPO were used to compare the erythropoiesis status and the efficiency of erythroid mobilization by flow cytometry. In this study, we found that G-CSF induced more orthochromatophilic erythroblast production than did EPO in the bone marrow and spleen. In addition, in contrast to EPO treatments, G-CSF treatments enhanced the efficiency of the mobilization of newly synthesized reticulocytes into peripheral blood. Our results demonstrated that the effects of G-CSF on erythropoiesis and erythrocytic mobilization were independent of EPO secretion and, in contrast to EPO, G-CSF promoted progression of erythropoiesis through transition of early stage R2 (basophilic erythroblasts) to late stage R4 (orthochromatophilic erythroblasts). We demonstrate for the first time that G-CSF treatments induce a faster erythropoiesis-enhancing response than that of EPO. These findings suggest an alternative approach to treating acute anemia, especially when patients are experiencing a clinical emergency in remote areas without proper blood bank supplies.

Virus-induced antibodies represent a dual-edged sword in the immune response to viral infections. While antibodies are critical for neutralizing pathogens, some can paradoxically exacerbate disease severity through mechanisms such as antibody-dependent enhancement (ADE), autoantibody, and prolonged inflammation. Long coronavirus disease (COVID) and dengue hemorrhagic fever (DHF) exemplify conditions where pathogenic antibodies play a pivotal role in disease progression. Long COVID is associated with persistent immune dysregulation and autoantibody production, leading to chronic symptoms and tissue damage. In DHF, pre-existing antibodies against dengue virus contribute to ADE, amplifying viral replication, immune activation, and vascular permeability. This review explores the mechanisms underlying these pathogenic antibody responses, highlighting the shared pathways of immune dysregulation and comparing the distinct features of both conditions. By examining these studies, we identify key lessons for therapeutic strategies, vaccine design, and future research aimed at mitigating the severe outcomes of viral infections.

Psychological stress is widely acknowledged as a major contributor to immunosuppression, rendering individuals more susceptible to various diseases. The complex interplay between the nervous, endocrine, and immune systems underlies stress-induced immunosuppression. However, the underlying mechanisms of psychological-stress-induced immunosuppression remain unclear. In this study, we utilized a restraint stress mouse model known for its suitability in investigating physiological regulations during psychological stress. Comparing it with cold exposure, we observed markedly elevated levels of stress hormones corticosterone and cortisol in the plasma of mice subjected to restraint stress. Furthermore, restraint-stress-induced immunosuppression differed from the intravenous immunoglobulin-like immunosuppression observed in cold exposure, with restraint stress leading to increased macrophage cell death in the spleen. Suppression of pyroptosis through treatments of inflammasome inhibitors markedly ameliorated restraint-stress-induced spleen infiltration and pyroptosis cell death of macrophages in mice. These findings suggest that the macrophage pyroptosis associated with restraint stress may contribute to its immunosuppressive effects. These insights have implications for the development of treatments targeting stress-induced immunosuppression, emphasizing the need for further investigation into the underlying mechanisms.

Psychological stress is associated with increased risk of gastrointestinal (GI) tract diseases. Evidence indicated that platelets facilitate GI tissue repair in intestinal anastomosis models. However, whether platelets are involved in native mechanism of the rescue of stress-induced GI injury for maintaining the GI homeostasis remains elusive. Because P-selectin-deficient (Selp^−/−) mice displayed higher stress-induced GI injury compared to the wild-type (Selp^+/+) mice, and P-selectin is specifically expressed in platelets, we hypothesize that P-selectin-expressing platelets play a protective role in the rescue of stress-induced GI injury. Our goal is to clarify the putative protective role of platelets in a GI system, thereby develop a feasible intervention strategy, such as platelet transfer, to overcome stress-induced GI injury. Through monitoring the plasma levels of GI-nonabsorbable Evans blue dye to reveal the progression course of GI injury in live mice, we found that intravenous treatments of purified platelets ameliorated stress-induced GI leakage. The transfer of platelets from wild-type mice was more potent than from Selp^−/− mice in the rescue of stress-induced-GI leakage in the recipients. As such, platelet transfer-mediated rescue was conducted in a P-selectin dependent manner. Additionally, platelet-mediated protection is associated with corrections of stress-induced aberrant GI mRNA expressions, including tight junctions claudin 3 and occludin, as well as stress-induced genes activating transcription factor 3 and AMP-activated protein kinase, after the transfer of wild-type platelets into wild-type and Selp^−/− mice. Furthermore, the stress-induced apoptosis of CD326⁺ GI epithelial cells was rescued by the transfer of wild type, but not P-selectin-deficient platelets. These results suggest that platelet plays a protective role for maintaining the GI homeostasis during stress in vivo, and that P-selectin is a molecular target for managing stress-induced GI tract injury.