PPARγ inhibits small airway remodeling through mediating the polarization homeostasis of alveolar macrophages in COPD.

The role of Peroxisome Proliferator-Activated Receptor-γ (PPARγ) in alveolar macrophages(AMs) polarization homeostasis is closely associated with airway remodeling in COPD, but the definite mechanism remains unclear. In this study, elevated percentage of M1-type AMs and the expression of functionally cytokines were found in COPD patients and mice, which closely related to the disease severity. PPARγ was markedly up-regulated in M2-type AMs and down-regulated in M1-type AMs, and was associated with disease severity in COPD. Co-cultured with M1- or M2-type AMs promoted the epithelial-mesenchymal transition (EMT) of airway epithelial cells and the proliferation of airway smooth muscle cells. Moreover, airway remodeling and functional damage were observed in both IL4R-/- COPD mice with runaway M1-type AMs polarization and TLR4-/- COPD mice with runaway M2-type AMs polarization. Cigarette extract (CS) or lipopolysaccharide (LPS) stimulated PPARγ-/- AMs showed more serious polarization disorder towards M1, as well as CS induced PPARγ-/- COPD mice, which led to more severe airway inflammation, lung function damage, and airway remodeling. Treatment with PPARγ agonist significantly improved the polarization disorder and function activity in CS/LPS stimulated-AMs by inhibiting the JAK-STAT, MAPK and NF-κB pathways, and alleviated the airway inflammation, restored the lung function and suppressed airway remodeling in CS induced-COPD mice. Our research demonstrates that polarization homeostasis of AMs mediated by PPARγ has the protective effect in airway remodeling, and may be a novel therapeutic target for the intervention and treatment of airway remodeling in COPD.

CTLA4Ig/VISTAIg combination therapy selectively induces CD4+ T cell-mediated immune tolerance by targeting the SOCS1 signaling pathway in porcine islet xenotransplantation.

T cell inhibitory receptors can regulate the proliferation or function of T cells by binding to their ligands and present a unique opportunity to manage destructive immune responses during porcine islet xenotransplantation. We applied ex vivo porcine islet xenotransplantation and in vitro mixed lymphocyte-islet reaction models to assess immune checkpoint receptor expression profiles in recipient T cells, investigated whether CTLA4 or VISTA immunoglobulin (Ig) combination therapy alone could suppress porcine islet xenograft rejection and further analyzed its potential immune tolerance mechanism. Recipient T cells expressed moderate to high levels of CTLA4, PD-1, TIGIT and VISTA, and the frequency of CTLA4+ CD4+ , TIGIT+ CD4+ , VISTA+ CD4+ and VISTA+ CD8+ T cells was positively correlated with porcine islet xenograft survival time in xenotransplant recipients. Combined treatment with CTLA4Ig and VISTAIg selectively inhibited recipient CD4+ T cell hyper-responsiveness and proinflammatory cytokine production and significantly delayed xenograft rejection. SOCS1 deficiency in CD4+ T cells stimulated by xenogeneic islets facilitated hyper-responsiveness and abolished the suppressive effect of combination therapy on recipient T cell-mediated porcine islet damage in vivo and in vitro. Further mechanistic studies revealed that combined treatment significantly induced SOCS1 expression and inhibited the Jak-STAT signalling pathway in wild-type recipient CD4+ T cells stimulated by xenogeneic islets, whereas SOCS1 deficiency resulted in Jak-STAT signalling pathway activation in recipient CD4+ T cells. We demonstrated a major role for CTLA4 and VISTA as key targets in CD4+ T cell hyper-responsiveness and porcine islet xenograft rejection. The selective inhibition of CD4+ T cell immunity by CTLA4Ig/VISTAIg is based on SOCS1-dependent signalling.

Off-label use of Baricitinib improves moderate and severe atopic dermatitis in China through inhibiting MAPK and PI3K/Akt/mTOR pathway via targeting JAK-STAT signaling of CD4+ cells.

As an inflammatory disease with a disrupted immune system, cytokine disorders in atopic dermatitis (AD) are closely related to the abnormal activation of JAK-STAT signal pathway. The critical relevance of the JAK-STAT signaling pathway to the pathogenesis of AD provides a strong rationale for JAK inhibitor research. Baricitinib, a small-molecule oral JAK inhibitor, has been proven to inhibit JAK-STAT signaling in a variety of diseases, including AD. It is currently available in China for off-label use. However, its efficacy in China and its mechanism are rarely reported. In our study, we found that the immune status of patients with moderate and severe AD was hyperactive. Among the 49 known immunotherapy targets, JAK1 and JAK2 genes on lymphocytes of AD patients were significantly upregulated, which was closely related to the symptom severity in moderate and severe AD patients. Baricitinib can improve immune hyperresponsiveness and clinical symptoms in moderate and severe AD by inhibiting the activation of Th2 cell subsets and the secretion of Th2-type cytokines through MAPK, mTOR and PI3K-Akt signaling pathways, providing an important theoretical basis for clinical off-label use of Baricitinib to treat moderate and severe AD.

Staphylococcal protein A-modified hydrogel facilitates in situ immunomodulation by capturing anti-HMGB1 for islet grafts.

Islet transplantation is regarded as the most promising therapy for type 1 diabetes. However, both hypoxia and immune attack impair the grafted islets after transplantation, eventually failing the islet graft. Although many studies showed that biomaterials with nanoscale pores, like hydrogels, could protect islets from immune cells, the pores on biomaterials inhibited vascular endothelial cells (VECs) to creep in, which resulted in poor revascularization. Thus, a hydrogel device that can facilitate in situ immune modulations without the cost of poor revascularization should be put forward. Accordingly, we designed a spA-modified hydrogel capturing anti-HMGB1 mAB (mAB-spA Gel): the Staphylococcus aureus protein A (spA) was conjugated on the network of hydrogel to capture anti-HMGB1mAB which can inactivate immune cells, while the pore sizes of the hydrogel were more than 100µm which allows vascular endothelial cells (VECs) to creep in. In this study, we screened the optimal spA concentration in mAB-spA Gel according to the physical properties and antibody binding capability, then demonstrated that it could facilitate in situ immunomodulation without decreasing the vessel reconstruction in vitro. Further, we transplanted islet graft in vivo and showed that the survival of islets was elongated. In conclusion, mAB-spA Gel provided an alternative islet encapsulation strategy for type 1 diabetes. STATEMENT OF SIGNIFICANCE: Although various studies have shown that the backbone of the hydrogels can isolate islets grafts from immune cells and the survival of the islets can be prolonged by this way, it is also reported that when the pore size of the backbone is too small the revascularization will be adversely affected. According to this point, it is hard to adjust hydrogel's pore size to protect the islets from the immune attack while allowing endothelial vascular cells to creep in. To solve this dilemma, we designed an immunomodulatory hydrogel inhibiting the activation of T cells by immunosuppressive IgGs instead of the backbone network, so the hydrogel can prolong the survival of islets without the sacrifice of revascularization.