Astragalus polysaccharides attenuate chemotherapy-induced immune injury by modulating gut microbiota and polyunsaturated fatty acid metabolism

BACKGROUND

The damage of chemotherapy drugs to immune function and intestinal mucosa is a common side effect during chemotherapy. Astragalus polysaccharides (APS) exhibit immunomodulatory properties and are recognized for preserving the integrity of the human intestinal barrier. Nevertheless, their application and mechanisms of action in chemotherapy-induced immune damage and intestinal barrier disruption remain insufficiently explored.

PURPOSE

This study delved into investigating how APS mitigates chemotherapy-induced immune dysfunction and intestinal mucosal injury, while also providing deeper insights into the underlying mechanisms.

METHODS

In a chemotherapy mice model induced by 5-fluorouracil (5-Fu), the assessment of APS's efficacy encompassed evaluations of immune organ weight, body weight, colon length, and histopathology. The regulation of different immune cells in spleen was detected by flow cytometry. 16S rRNA gene sequencings, ex vivo microbiome assay, fecal microbiota transplantation (FMT), and targeted metabolomics analysis were applied to explore the mechanisms of APS effected on chemotherapy-induced mice.

RESULTS

APS ameliorated chemotherapy-induced damage to immune organs and regulated immune cell differentiation disorders, including CD4+T, CD8+T, CD19+B, F4/80+CD11B+ macrophages. APS also alleviated colon shortening and upregulated the expression of intestinal barrier proteins. Furthermore, APS significantly restored structure of gut microbiota following chemotherapy intervention. Ex vivo microbiome assays further demonstrated the capacity of APS to improve 5-Fu-induced microbiota growth inhibition and compositional change. FMT demonstrated that the regulation of gut microbiota by APS could promote the recovery of immune functions and alleviate shortening of the colon length. Remarkably, APS significantly ameliorated the imbalance of linoleic acid (LA) and α-linolenic acid in polyunsaturated fatty acid (PUFA) metabolism. Further in vitro experiments showed that LA could promote splenic lymphocyte proliferation. In addition, both LA and DGLA down-regulated the secretion of NO and partially up-regulated the percentage of F4/80+CD11B+CD206+ cells.

CONCLUSION

APS can effectively ameliorate chemotherapy-induced immune damage and intestinal mucosal disruption by regulating the composition of the gut microbiota and further restoring PUFA metabolism. These findings indicate that APS can serve as an adjuvant to improve the side effects such as intestinal and immune damage caused by chemotherapy.

Bioinformatics analysis of SARS-CoV-2 infection-associated immune injury and therapeutic prediction for COVID-19

Background

Severe acute respiratory syndrome coronavirus 2 is a highly contagious viral infection, without any available targeted therapies. The high mortality rate of COVID-19 is speculated to be related to immune damage.

Methods

In this study, clinical bioinformatics analysis was conducted on transcriptome data of coronavirus infection.

Results

Bioinformatics analysis revealed that the complex immune injury induced by coronavirus infection provoked dysfunction of numerous immune-related molecules and signaling pathways, including immune cells and toll-like receptor cascades. Production of numerous cytokines through the Th17 signaling pathway led to elevation in plasma levels of cytokines (including IL6, NF-κB, and TNF-α) followed by concurrent inflammatory storm, which mediates the autoimmune response. Several novel medications seemed to display therapeutic effects on immune damage associated with coronavirus infection.

Conclusions

This study provided insights for further large-scale studies on the target therapy on reconciliation of immunological damage associated with COVID-19.

C5b-9 membrane attack complex activated NLRP3 inflammasome mediates renal tubular immune injury in trichloroethylene sensitized mice

Trichloroethylene (TCE) induced occupational medicamentosa-like dermatitis (OMLDT) in patients is accompanied, typically, by renal damage. But the role of C5b-9 and IL-1β in TCE-sensitized mouse renal tubular damage is unclear. This study aimed to investigate whether TCE-sensitized mouse renal tubular epithelial cell damage was induced by NLRP3 inflammasome and whether NLRP3 inflammasome was activated by sublytic C5b-9. In total, 52 specific pathogen-free BALB/c female mice, 6- to 8-week-old, were used for establishing the TCE-sensitized mouse model. Renal tubular epithelial cells were isolated and used for determining the sublytic level of C5b-9. Kidney histological examination, serum neutrophil gelatinase associated lipocalin (NGAL) level were used for kidney damage evaluation. Renal protein levels of C5b-9, NLRP3, ASC, Caspase-1, IL-1β, and IL-18 were measured. The renal lesions, serum NGAL level, renal NLRP3, ASC, Caspase-1 and IL-1β protein levels all increased significantly in TCE sensitized positive group. However, pretreatment with recombinant protein sCD59-Cys inhibited the expression of C5b-9, NLRP3 inflammasome, IL-1β, IL-18, and attenuated renal tubular epithelial cell damage. The sublytic C5b-9 activated NLRP3 inflammasome and aggravated renal tubular epithelial cell damage. Pretreatment with recombinant protein sCD59-Cys blocked the expression of the NLRP3 inflammasome by inhibiting the expression of C5b-9, and alleviating renal tubular epithelial cell damage.

Intracellular complement activation in podocytes aggravates immune kidney injury in trichloroethylene-sensitized mice

Trichloroethylene (TCE) as a common organic solvent in industrial production can cause occupational medicamentosa-like dermatitis (OMDT) in some exposed workers. In addition to systemic skin damage, OMDT is also accompanied by severe kidney injury. Our previous studies show that complement (C) plays an important role in immune kidney injury caused by TCE. Specifically, C3 is mainly deposited on glomeruli. Recent studies have found that intracellular complement can be activated by cathepsin L (CTSL) and exert a series of biological effects. The purpose of this study was to explore where C3 on glomeruli comes from and what role it plays. A BALB/c mouse model of skin sensitization induced by TCE in the presence or absence of CTSL inhibitor (CTSLi,10 mg/kg). In TCE sensitization-positive mice, C3 was mainly expressed on podocytes and the expression of CTSL significantly increased in podocytes. Kidney function test and related indicators showed abnormal glomerular filtration and transmission electron microscopy revealed ultrastructure damage to podocytes. These lesions were alleviated in TCE/CTSLi positive mice. These results provide the first evidence that in TCE-induced immune kidney injury, intracellular complement in podocytes can be over-activated by CTSL and aggravates podocytes injury, thereby damaging glomerular filtration function. Intracellular complement activation and cathepsin L in podocytes may be a potential target for treating immune kidney injury induced by TCE.

[Immunological damage effects of cytomegalovirus infection on bone marrow hematopoietic cells]

Objective: Toobserve the damage effects of cytomegalovirus (CMV) infection on hematopoietic cells and to investigate the clinical significance. Methods: (1) ELISA assay wasused to detect IL-17 and IFN-γ levels in the peripheral blood serum of 36 patients on pretherapy and posttherapy. (2) Changes of peripheral blood lymphocyte subsets were detected by FACS. (3) Cytological observation of cervical lymph nodes was executed by needle aspiration cytology. (4) Cellular immunochemistry and immunofluorescence staining were performed to observe the POX release, HLA-DR expression, IL-17A and IFN-γ secretion-like expression status of activated immune cells in the bone marrow hematopoietic microenvironment. Serum samples from healthy individuals were used as controls. Bone marrow smears from patients without iron deficiency anemia were compared as bone marrow immunostaining. Results: (1) Serum levels of IL-17 and IFN-γ were significantly increased in CMV-infected patients [IL-17 (48.23±3.86) ng/L vs (20.16±1.05) ng/L,respectively; IFN-γ (40.16±3.11) vs (8.17±1.92) ng/L,P<0.01]. (2) The proportion of CD16+/CD56+NK cells was significantly increased in patients [(43.54±6.01)% vs (14.01±3.25)%, P<0.01]. The proportion of CD3+CD4+T and CD3+CD8+T cells decreased,(20.91±53.15)% vs (35.10±4.88)%, and (15.41±5.13)% vs (25.11±3.92)%,respectively,P<0.05. (3) Large numbers of abnormal lymphocytes and macrophages (MΦ) that engulf large quantities of CMV inclusion bodies were observed in bone marrow and lymph nodes. CMV infected and destroied the hematopoietic cells of various lines in the bone marrow. The activated MΦ phagocytizedthe CMV inclusion bodies and also phagocytosed CMV-infected blood cells. (4) Activated MΦ in bone marrow hematopoietic microenvironment released POX strongly positive, highly expressed class Ⅱ HLA-DR, and highly expressed inflammatory factors IL-17A and IFN-γ. (5) Twenty-twopatients with elevated WBC were treated with ganciclovir combined with antibiotics for 2 weeks after the disappearance of the foci, WBC counts and CMV-IgM levels of 16 cases were reduced to normal.Six patients with CMV who were not turned negative were tprolonged,and the granulocyte and/or platelet counts fell below normal range. Fourteenpatients withreduced granulocyte or platelet count, CMV-IgM levels were slow descend,and the ganciclovir treated more than 4 weeks. Conclusions: CMV can infect hematopoietic bone marrow nucleated blood cells and destroy hematopoiesis. NK and MΦ cells are important effector cells against CMV infection. Activated macrophages are dual in nature, they can engulf CMV virus and virus-infected blood cells,and also aggravate bone marrow immune damage by releasing inflammatory factors such as POX and IL-17A and IFN-γ.

Hydrogen sulfide inhalation-induced immune damage is involved in oxidative stress, inflammation, apoptosis and the Th1/Th2 imbalance in broiler bursa of Fabricius

Hydrogen sulfide (H₂S) is widely accepted to be a signaling molecule that exhibits some potentially beneficial therapeutic effects at physiological concentrations. At elevated levels, H₂S is highly toxic and has a negative effect on human health and animal welfare. Studies have shown that H₂S exposure induces an immune function in mice, but there are few studies of the effect of continuous H₂S exposure on immune organs in poultry. In this study, one-day-old broilers were selected and exposed to 4 or 20 ppm of H₂S gas for 14, 28 and 42 days of age. After exposure, the bursa of Fabricius (BF) was harvested. The results showed that continuous H₂S exposure reduced the body weight, abdominal fat percentage, and antibody titer in broilers. H₂S exposure also decreased mRNA expression of IgA, IgM and IgG in the broiler BF. A histological study revealed obvious nuclear debris, and a few vacuoles in the BF, and an ultrastructural study revealed mitochondrial and nuclear damage to BF cells after H₂S exposure for 42 d. Terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay suggested H₂S exposure remarkably increased the number of TUNEL positive nuclei and significantly increased apoptotic index. The expression of apoptotic genes also confirmed that H₂S inhalation damaged the broiler BF. Increased cytokines and reduced antioxidant responses were detected in the BF after exposure to H₂S. Cytokines promoted inflammation and caused a Th1/Th2 imbalance. We suggest that continuous H₂S intoxication triggers oxidative stress, inflammation, apoptosis and a Th1/Th2 imbalance in the BF, leading to immune injury in broilers.

[Study the role of lysosome-associated membrane protein type 2A for immune-mediated liver injury of primary biliary cholangitis]

Objective: To investigate the role of lysosome-associated membrane protein type 2A (LAMP-2A) for immune-mediated liver injury of primary biliary cholangitis (PBC). Methods: The association between LAMP-2A expression and PBC was examined by immunohistochemistry and electron microscopy in liver tissue samples from patients with PBC. Furthermore, the immunological damage of LAMP-2A overexpression on mouse liver was observed by adeno-associated virus (AAV) overexpression technique. The expression level of mRNA was analyzed by Student's t-test. The data were graphed and analyzed statistically using graphpad prism 5 (GraphPad Software).A value of p < 0.05 was considered statistically significant. Results: The expression of LAMP-2A in liver tissue of PBC patients was increased, and the autophagosome formation was observed in hepatocytes. C57BL/6 mice were injected into the caudal vein with LAMP-2A AAV for 6 weeks. The formation of autophagosomes in mouse hepatocytes was increased significantly. The expression of related molecules was abnormal; simultaneously, the degree of lymphocyte infiltration in the liver tissue of mice was significantly higher than the control group. Conclusion: An overexpression of LAMP-2A in the liver of patients with PBC may induce and/or promote the hepatic inflammatory response, especially the portal inflammatory infiltrate.

Mechanisms of esophageal epithelial injury in gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) is a disease frequently encountered in gastroenterology department. Domestic scholars paid much attention on the anatomical basis of reflux when trying to describe the mechanisms of GERD, such as the decrease of tension of the lower esophageal sphincter (LES) and a transient lower esophageal sphincter (tLESR) and diaphragmatic hernia, and neglected the pathophysiological mechanisms of esophageal epithelial histological changes including cell necrosis, dilated intercellular space (DIS), and infiltration of inflammatory cells which were induced by the reflux contents including gastric acid, pepsin and bile. In this paper, we will elaborate the mechanisms of esophageal epithelia injury induced by common reflux contents at the cellular and molecular levels, focusing on the introduction and analysis of immune injury mechanism.

Apolipoprotein E-knockout mice on high-fat diet show autoimmune injury on kidney and aorta

BACKGROUND

Apolipoprotein E-knockout (ApoE(-/-)) mice is a classic model of atherosclerosis. We have found that ApoE(-/-) mice showed splenomegaly, higher titers of serum anti-nuclear antibody (ANA) and anti-dsDNA antibody compared with C57B6/L (B6) mice. However, whether ApoE(-/-) mice show autoimmune injury remains unclear.

METHODS AND RESULTS

Six females and six males in each group, ApoE(-/)(-), Fas(-/-) and B6 mice, were used in this study. The titers of serum ANA, anti-dsDNA antibody and creatinine and urine protein were measured by ELISA after 4 months of high-fat diet. The spleen weight and the glomerular area were determined. The expressions of IgG, C3 and macrophage in kidney and atherosclerotic plaque were detected by immunostaining followed by morphometric analysis. Similar to the characteristics of Fas(-/-) mice, a model of systemic lupus erythematosus (SLE), ApoE(-/-) mice, especially female, displayed significant increases of spleen weight and glomerular area when compared to B6 mice. Also, elevated titers of serum ANA, anti-dsDNA antibody and creatinine and urine protein. Moreover, the expressions of IgG, C3 and macrophage in glomeruli and aortic plaques were found in ApoE(-/-) mice. In addition, the IgG and C3 expressions in glomeruli and plaques significantly increased (or a trend of increase) in female ApoE(-/-) mice compared with males.

CONCLUSIONS

Apolipoprotein E-knockout mice on high-fat diet show autoimmune injury on kidney and aorta.