LPS-induced airway-centered inflammation leading to BOS-like airway remodeling distinct from RAS-like fibrosis in rat lung transplantation. Transplantation. 2020;Online ahead of print. [PMID: 31929420 DOI: 10.1097/tp.0000000000003097]

Network pharmacology and experimental evidence: MAPK signaling pathway is involved in the anti-asthma roles of Perilla frutescens leaf

Perilla frutescens (PF) leaf is a traditional Chinese medicine and food with beneficial effects on allergic asthma. We sought to elucidate the active compounds, the targets, and underlying mechanisms of PF leaf in the treatment of allergic asthma by using experimental pharmacology and network pharmacology. An OVA-allergic asthma murine model was constructed to evaluate the effect of PF leaf on allergic asthma. And the network pharmacology and western blotting were performed to evaluate its underlying mechanisms in allergic asthma. PF leaf treatment significantly improved the lung function of OVA model mice and mitigated lung injury by significantly reducing of OVA-specific immunoglobulin E in serum, and interleukin 4, interleukin 5 and tumor necrosis factor alpha in the bronchoalveolar lavage fluid. 50 core targets were screened based on 8 compounds (determined by high performance liquid chromatography) through compound-target- disease network. Furthermore, MAPK signaling pathway was identified as the pathway mediated by PF leaf with the most potential against allergic asthma. And the WB results showed that PF leaf could down-regulate the expression of p-ERK, p-JNK and p-p38, which was highly consistent with the predicted targets and pathway network. In conclusion, this study provides the evidence to support the molecular mechanisms of PF leaf on the treatment of allergic asthma using network pharmacology and in vivo experiments.

Donor IL-17 receptor A regulates LPS-potentiated acute and chronic murine lung allograft rejection

Chronic lung allograft dysfunction (CLAD) is a major complication after lung transplantation that results from a complex interplay of innate inflammatory and alloimmune factors, culminating in parenchymal and/or obliterative airway fibrosis. Excessive IL-17A signaling and chronic inflammation have been recognized as key factors in these pathological processes. Herein, we developed a model of repeated airway inflammation in mouse minor alloantigen-mismatched single-lung transplantation. Repeated intratracheal LPS instillations augmented pulmonary IL-17A expression. LPS also increased acute rejection, airway epithelial damage, and obliterative airway fibrosis, similar to human explanted lung allografts with antecedent episodes of airway infection. We then investigated the role of donor and recipient IL-17 receptor A (IL-17RA) in this context. Donor IL-17RA deficiency significantly attenuated acute rejection and CLAD features, whereas recipient IL-17RA deficiency only slightly reduced airway obliteration in LPS allografts. IL-17RA immunofluorescence positive staining was greater in human CLAD lungs compared with control human lung specimens, with localization to fibroblasts and myofibroblasts, which was also seen in mouse LPS allografts. Taken together, repeated airway inflammation after lung transplantation caused local airway epithelial damage, with persistent elevation of IL-17A and IL-17RA expression and particular involvement of IL-17RA on donor structural cells in development of fibrosis.

miR-27a-3p alleviates lung transplantation-induced bronchiolitis obliterans syndrome (BOS) via suppressing Smad-mediated myofibroblast differentiation and TLR4-induced dendritic cells maturation

BACKGROUND

Bronchiolitis obliterans syndrome (BOS), induced by a chronic rejection, remains a significant obstacle for end-stage lung diseases after lung transplantation. We have previously determined that the small non-coding mRNA (miRNA) miR-27a-3p maintained the immature state of dendritic cells (DCs) via the interleukin 10 (IL-10)-dependent regulatory pathway. Such status helped in preventing rejection and alleviating BOS. The present study explored mechanisms how miR-27a-3p may suppress the fibrosis as well as the maturation of DCs, ultimately attenuating BOS in vitro and in vivo.

METHODS/RESULTS

In our tracheal transplantation mouse model, the expression of Smad2, Smad4, and αSMA were significantly decreased in the miR-27a-3p-transfected DCs (p < 0.0001, p = 0.0006, and p = 0.0002 respectively). Moreover, the expression of fibrosis markers (α-SMA, collagen I, and Fn) were potently inhibited in the miR-27a-3p-transfected NIH-3 T3 cells (p < 0.0001, p = 0.00148, and p < 0.0001 respectively). At the same time, reversed results were observed in the inhibitor group (p = 0.0002, p < 0.0001, and p < 0.0001 respectively), indicating that miR-27a-3p could directly inhibit myofibroblast differentiation. Furthermore, in the tracheal transplanted mice, the population of Treg cells was significantly decreased (p < 0.0001). In contrast, Th17 cells were down-regulated in the miR-27a-3p-transfected DCs group (p < 0.0001), accompanied by the decreased IL-17 levels (p = 0.0007) and the induction of TGF-β1 and IL-10 (p < 0.0001 and p = 0.0016 respectively). Further mechanistic studies indicated that miR-27a-3p altered the maturation of DCs by targeting TLR4 and IRAK (p < 0.0001 and p = 0.0002 respectively).

CONCLUSIONS

Our study suggests that miR-27a-3p selectively blocked the TGF-β1/Smad pathways to suppress the myofibroblast differentiation and targeted the TRL4/IRAK4 pathway to restrain DCs maturation, thus attenuating BOS. Our findings suggest that miR-27a-3p is a potential active molecule on BOS management after lung transplantation.

Long-lasting effects of lipopolysaccharide on the reproduction and splenic transcriptome of hens and their offspring

Lipopolysaccharide (LPS) is ubiquitous in the environment and is released after the death of gram-negative bacteria, which may be related to inflammation and immunosuppression. However, its impact on the reproduction of animals and their offspring, especially the underlying mechanism need further elucidation. Here, we used laying hens as a model organism to investigate the effects of maternal exposure to LPS (LPS maternal stimulation) on animal and their offspring's immunity and reproductive performance, as well as the regulatory role of the transcriptome. We found that the LPS maternal stimulation could reduce the egg-laying rate of hens and their offspring, especially during the early and late laying stages. The transcriptome study of the spleen in F0, F1 and F2 generations showed that the maternal stimulation of the LPS affects the patterns of gene expression in laying hens, and this change has a long-lasting effect. Further analysis of DEGs and their enrichment pathways found that the LPS maternal stimulation mainly affects the reproduction and immunity of laying hens and their offspring. The DEGs such as AVD, HPS5, CATHL2, S100A12, EXFABP, RSFR, LY86, PKD4, XCL1, FOS, TREM2 and MST1 may play an essential role in the regulation of the immunity and egg-laying rate of hens. Furthermore, the MMR1L3, C3, F13A1, LY86 and GDPD2 genes with heritable effects are highly correlated with the egg-laying rate, may have an important reference value for further research. Our study reveals the profound implications of LPS exposure on immunity and reproduction of offspring, elaborating the impact of immune alteration on the egg-laying rate, emphasizing the regulatory role of intergenerational transmission of the transcriptome, implying that the environment parents being exposed to has an important impact on offspring.

Effect of MMF Immunosuppression Based on CNI Reduction on CNI-Related Renal Damage after Lung Transplantation

In this paper, numerous effects of immunosuppressive regimen of mycophenolate mofetil (MMF) on CNI-related renal damage after lung transplantation are evaluated thoroughly. For this purpose, 110 lung transplant recipients who were treated in our hospital from March 2016 to January 2018 were randomly selected. All patients took prednisone acetate tablets or rapamycin at the same time or not at the same time. MMF is 1 g every time, twice a day, and adjusted according to the re-examination. According to the different drugs taken by 110 patients, they were divided into cyclosporine A group and tacrolimus group. Among them, 92 patients in cyclosporine A group took cyclosporine A; 18 patients in tacrolimus group took tacrolimus. The clinical data of age and gender of the two groups were collected, To observe and compare the occurrence of CNI-related renal damage in lung transplant recipients and different immunosuppressants. The CNI dosage of tacrolimus group and cyclosporine A group was compared before and after MMF. The changes of serum creatinine level and serum creatinine clearance rate were measured before MMF administration and 30, 60, and 90 days after MMF administration, to observe the complications of CNI-related renal damage after lung transplantation. Experimental results showed that there were 16 cases (14.55%) of CNI-related renal damage in lung transplant recipients and different immunosuppressants, including 10 cases (11.36%) in males, 6 cases (27.27%) in females, 11 cases (12.09%) in tacrolimus group, and 5 cases (26.32%) in cyclosporine A group. There was no significant difference between the two groups (P > 0.05). Compared with MMF before and after administration, CNI dosage of cyclosporine A group and tacrolimus group decreased significantly (P < 0.01). Compared with MMF before administration, serum creatinine level decreased and serum creatinine clearance rate increased significantly (P < 0.05). In the follow-up, 16 patients with CNI-related renal damage were found to be immune rejection before the adjustment of immunosuppression program, no complications such as immune rejection, myelosuppression, and infection occurred within 15 months after the adjustment of immunosuppression program, blood glucose increased in 3 patients within 2 years after operation, blood lipid increased in 1 patient, urea increased in 1 patient, and uric acid increased in 1 patient. MMF immunosuppressive therapy based on CNI reduction is a safe and effective immunosuppressive therapy, which can significantly reduce immune rejection, improve renal function, and play an important role in improving CNI-related renal damage after lung transplantation.

Chronic lung allograft dysfunction post-lung transplantation: The era of bronchiolitis obliterans syndrome and restrictive allograft syndrome

Chronic lung allograft dysfunction (CLAD) following lung transplantation limits long-term survival considerably. The main reason for this is a lack of knowledge regarding the pathological condition and the establishment of treatment. The consensus statement from the International Society for Heart and Lung Transplantation on CLAD in 2019 classified CLAD into two main phenotypes: Bronchiolitis obliterans syndrome and restrictive allograft syndrome. Along with this clear classification, further exploration of the mechanisms and the development of appropriate prevention and treatment strategies for each phenotype are desired. In this review, we summarize the new definition of CLAD and update and summarize the existing knowledge on the underlying mechanisms of bronchiolitis obliterans syndrome and restrictive allograft syndrome, which have been elucidated from clinicopathological observations and animal experiments worldwide.

Bronchiolitis obliterans syndrome and restrictive allograft syndrome after lung transplantation: why are there two distinct forms of chronic lung allograft dysfunction?

Bronchiolitis obliterans syndrome (BOS) had been considered to be the representative form of chronic rejection or chronic lung allograft dysfunction (CLAD) after lung transplantation. In BOS, small airways are affected by chronic inflammation and obliterative fibrosis, whereas peripheral lung tissue remains relatively intact. However, recognition of another form of CLAD involving multiple tissue compartments in the lung, termed restrictive allograft syndrome (RAS), raised a fundamental question: why there are two phenotypes of CLAD? Increasing clinical and experimental data suggest that RAS may be a prototype of chronic rejection after lung transplantation involving both cellular and antibody-mediated alloimmune responses. Some cases of RAS are also induced by fulminant general inflammation in lung allografts. However, BOS involves alloimmune responses and the airway-centered disease process can be explained by multiple mechanisms such as external alloimmune-independent stimuli (such as infection, aspiration and air pollution), exposure of airway-specific autoantigens and airway ischemia. Localization of immune responses in different anatomical compartments in different phenotypes of CLAD might be associated with lymphoid neogenesis or the de novo formation of lymphoid tissue in lung allografts. Better understanding of distinct mechanisms of BOS and RAS will facilitate the development of effective preventive and therapeutic strategies of CLAD.

The role of innate immunity in the long-term outcome of lung transplantation

Long-term survival after lung transplantation remains suboptimal due to chronic lung allograft dysfunction (CLAD), a progressive scarring process affecting the graft. Although anti-donor alloimmunity is central to the pathogenesis of CLAD, its underlying mechanisms are not fully elucidated and it is neither preventable nor treatable using currently available immunosuppression. Recent evidence has shown that innate immune stimuli are fundamental to the development of CLAD. Here, we examine long-standing assumptions and new concepts linking innate immune activation to late lung allograft fibrosis.