Hao Cao

Autophagy facilitates TLR4- and TLR3-triggered migration and invasion of lung cancer cells through the promotion of TRAF6 ubiquitination.

Autophagy contributes to the pathogenesis of cancer, whereas toll-like receptors (TLRs) also play an important role in cancer development and immune escape. However, little is known about the potential interaction between TLR signaling and autophagy in cancer cells. Here we show that autophagy induced by TLR4 or TLR3 activation enhances various cytokine productions through promoting TRAF6 (TNF receptor-associated factor 6, E3 ubiquitin protein ligase) ubiquitination and thus facilitates migration and invasion of lung cancer cells. Stimulation of TLR4 and TLR3 with lipopolysaccharide (LPS) and polyinosinic-polycytidylic acid [poly(I:C)] respectively triggered autophagy in lung cancer cells. This was mediated by the adaptor protein, toll-like receptor adaptor molecule 1 (TICAM1/TRIF), and was required for TLR4- and TLR3-induced increases in the production of IL6, CCL2/MCP-1 [chemokine (C-C motif) ligand 2], CCL20/MIP-3α [chemokine (C-C motif) ligand 20], VEGFA (vascular endothelial growth factor A), and MMP2 [matrix metallopeptidase 2 (gelatinase A, 72 kDa gelatinase, 72 kDa type IV collagenase)]. These cytokines appeared to be necessary for enhanced migration and invasion of lung cancer cells upon TLR activation. Remarkably, inhibition of autophagy by chemical or genetic approaches blocked TLR4- or TLR3-induced Lys63 (K63)-linked ubiquitination of TRAF6 that was essential for activation of MAPK and NFKB (nuclear factor of kappa light polypeptide gene enhancer in B-cells) pathways, both of which were involved in the increased production of the cytokines. Collectively, these results identify induction of autophagy by TLR4 and TLR3 as an important mechanism that drives lung cancer progression, and indicate that inhibition of autophagy may be a useful strategy in the treatment of lung cancer.

Tissue resident regulatory T cells: novel therapeutic targets for human disease

Over the past decade, the ability of regulatory T cells (Tregs) to suppress multiple types of immune cells has received tremendous attention. Mounting evidence has revealed that tissue resident Tregs control non-immunological processes of their target tissues and contribute to a plethora of human diseases. The identification of novel tissue-specific Tregs has highlighted their heterogeneity and complexity. This review summarizes the recent findings for visceral adipose tissue CD4+Foxp3+ regulatory T cells (VAT Tregs), muscle Tregs, bone Tregs and skin memory Tregs, with a focus on their unique functions in local tissues. This interpretation of the roles of tissue-specific Tregs and of their involvement in disease progression provides new insight into the discovery of potential therapeutic targets of human diseases.

CD4+ Foxp3+ regulatory T cells induced by TGF-β, IL-2 and all-trans retinoic acid attenuate obliterative bronchiolitis in rat trachea transplantation.

Obliterative bronchiolitis (OB) is the major obstacle for long-term allograft survival in lung transplantation, and the underlying mechanism is still not well understood. Regulatory T cells (Tregs) have been shown to be essential in the maintenance of immune tolerance. In this study we investigated the role of Tregs in protecting OB in rat. We show that the combination of TGF-β, Interleukin (IL)-2, and all-trans retinoic acid (atRA) could induce naïve rat CD4(+)CD25(-) T cells to differentiate into CD4(+)CD25(+)Foxp3(+) T cells in vitro, and they acquired suppressive function. In a rat orthotopic tracheal transplantation OB model, the adoptive transfer of the induced Tregs reduced symptoms of airway obliteration and fibrication of grafts when compared with adoptive transfer of control cells without suppressive property. Moreover, recipients treated with the induced Tregs secreted high level of immunosuppressive cytokine TGF-β and IL-10, and low level of pro-inflammatory cytokines IL-17, IFN-γ, IL-6, and MCP-1, and had fewer effector T cells including Th17 cells and Th1 cells in the graft. Taken together, these findings suggest that in vitro induced Tregs by the combination of TGF-β, IL-2, and atRA are effective in protecting rat trachea allograft rejection through the inhibition of effector T cells and their function. These datas implicate new therapies to prevent OB and allograft rejection in human lung transplantation.

Autophagy induced by DAMPs facilitates the inflammation response in lungs undergoing ischemia-reperfusion injury through promoting TRAF6 ubiquitination

Lung ischemia-reperfusion (I/R) injury remains one of the most common complications after various cardiopulmonary surgeries. The inflammation response triggered by the released damage-associated molecular patterns (DAMPs) aggravates lung tissue damage. However, little is known about the role of autophagy in the pathogenesis of lung I/R injury. Here, we report that a variety of inflammation-related and autophagy-associated genes are rapidly upregulated, which facilitate the inflammation response in a minipig lung I/R injury model. Left lung I/R injury triggered inflammatory cytokine production and activated the autophagy flux as evidenced in crude lung tissues and alveolar macrophages. This was associated with the release of DAMPs, such as high mobility group protein B1 (HMGB1) and heat shock protein 60 (HSP60). Indeed, treatment with recombinant HMGB1 or HSP60 induced autophagy in alveolar macrophages, whereas autophagy inhibition by knockdown of ATG7 or BECN1 markedly reduced DAMP-triggered production of inflammatory cytokines including IL-1β, TNF and IL12 in alveolar macrophages. This appeared to be because of decreased activation of MAPK and NF-κB signaling. Furthermore, knockdown of ATG7 or BECN1 inhibited Lys63 (K63)-linked ubiquitination of TNF receptor-associated factor 6 (TRAF6) in DAMP-treated alveolar macrophages. Consistently, treatment with 3-MA inhibited K63-linked ubiquitination of TRAF6 in I/R-injured lung tissues in vivo. Collectively, these results indicate that autophagy triggered by DAMPs during lung I/R injury amplifies the inflammatory response through enhancing K63-linked ubiquitination of TRAF6 and activation of the downstream MAPK and NF-κB signaling.

Mesenchymal stem cells reprogram host macrophages to attenuate obliterative bronchiolitis in murine orthotopic tracheal transplantation.

After lung transplantation, obliterative bronchiolitis (OB) is one of the major limitations for the long-term survival of allografts. At present, effective treatment to prevent this phenomenon remains elusive. Mesenchymal stem cells (MSCs) are capable of modulating the immune system through the interaction with a wide range of immune cells. Here, we found that treatment of mice with bone marrow derived MSCs prevents the development of airway occlusion and increased IL-10 levels in trachea grafts, which was eliminated by the depletion of macrophages. Mechanistically, MSCs-derived PGE2, through the receptors EP2 and EP4, promoted the release of IL-10 and inhibited the production of IL-6 and TNF-α by macrophages. These results suggest that MSCs can both decrease the innate inflammatory responses and prevent allograft rejection by down-regulating the levels of IL-6 and TNF-α and increasing IL-10 production respectively. For easy availability and immune privilege, MSC-based treatment of OB provides an effective strategy for regulation of immune responses in lung transplantation.

Anti-IL-23 antibody blockade of IL-23/IL-17 pathway attenuates airway obliteration in rat orthotopic tracheal transplantation

Obliterative bronchiolitis (OB) has been a major obstacle to long-term allograft survival after lung transplantation, and the underlying mechanism is not well understood. As IL-23/IL-17 pathway has been shown to play important roles in airway inflammation, in this study we have investigated the role of IL-23/IL-17 pathway in acute and chronic airway allograft rejection. We used a rat OB model in orthotopic tracheal transplantation, and investigated the effects of anti-IL-23 blockade antibody on acute and chronic airway allograft rejection. Anti-IL-23 antibody impaired the function of IL-23 in inducing IL-17 production. The rats that received allografts and treated with anti-IL-23 antibody showed significantly less symptom of airway obliteration and chronic transplant rejection compared with control rats which received physiological saline or IgG antibody. Taken together, our results suggest that anti-IL-23 antibody is effective in protecting allograft rejection and the development of chronic OB in allo-tracheal transplantation. These findings may have implications for new therapies to prevent OB and allograft rejection in human lung transplantation.

Phosphatase PP4 Negatively Regulates Type I IFN Production and Antiviral Innate Immunity by Dephosphorylating and Deactivating TBK1

The effective recognition of viral infection and subsequent type I IFN production is essential for the host antiviral innate immune responses. The phosphorylation and activation of kinase TANK-binding kinase 1 (TBK1) plays crucial roles in the production of type I IFN mediated by TLR and retinoic acid–inducible gene I–like receptors. Type I IFN expression must be tightly regulated to prevent the development of immunopathological disorders. However, how the activated TBK1 is negatively regulated by phosphatases remains poorly understood. In this study, we identified a previously unknown role of protein phosphatase (PP)4 by acting as a TBK1 phosphatase. PP4 expression was upregulated in macrophages infected with RNA virus, vesicular stomatitis virus, and Sendai virus in vitro and in vivo. Knockdown of PP4C, the catalytic subunit of PP4, significantly increased type I IFN production in macrophages and dentritic cells triggered by TLR3/4 ligands, vesicular stomatitis virus, and Sendai virus, and thus inhibited virus replication. Similar results were also found in peritoneal macrophages with PP4C silencing in vivo and i.p. infection of RNA virus. Accordingly, ectopic expression of PP4C inhibited virus-induced type I IFN production and promoted virus replication. However, overexpression of a phosphatase-dead PP4C mutant abolished the inhibitory effects of wild-type PP4C on type I IFN production. Mechanistically, PP4 directly bound TBK1 upon virus infection, then dephosphorylated TBK1 at Ser172 and inhibited TBK1 activation, and subsequently restrained IFN regulatory factor 3 activation, resulting in suppressed production of type I IFN and IFN-stimulated genes. Thus, serine/threonine phosphatase PP4 functions as a novel feedback negative regulator of RNA virus-triggered innate immunity.

Giant Coronary Artery Aneurysm With Fistula to the Pulmonary Artery Complicated by Frequent Ventricular Premature Contractions: A Case Report

AbstractGiant coronary artery aneurysm with a fistula is a rare condition. The presence of a giant aneurysm imposes considerable health risks.We report a case of a 67-year-old woman who presented with frequent ventricular premature contractions caused by a giant coronary aneurysm arising from a branch of the left anterior descending coronary artery that had a fistulous connection to the pulmonary artery.The patient was referred for cardiac surgery. The giant aneurysm was resected, and the proximal and distal openings were closed directly. The main pulmonary artery was opened longitudinally and the fistula was also closed directly.The patients symptoms of frequent ventricular premature contractions disappeared postoperatively as confirmed by electrocardiography.Although the standard therapeutic strategies of the disease are not well established because of the rarity of this condition, our clinical results indicate that the surgical treatment is an effective choice.

CD28 superagonist antibody treatment attenuated obliterative bronchiolitis in rat allo-orthotopic tracheal transplantation by preferentially expanding Foxp3-expressing regulatory T cells.

Obliterative airway disease (OAD) due to chronic alloantigen rejection remains a major challenge for long-term graft survival in lung transplantation. It is known that superagonistic CD28-specific monoclonal antibody JJ316 (supCD28 MAb) has the ability to induce regulatory T cells (Tregs) efficiently. Here we used a rat orthotopic tracheal transplantation model to investigate the effects of supCD28 MAb on expanding Tregs in vivo and its application in suppression of acute and chronic airway allograft rejection. SupCD28 MAb administration revealed a significant increase in the CD4+CD25+ T cells, CD4+FoxP3+ T cells, and CD4+CD25+ FoxP3+ T cells population among CD4+ T cells in spleen, peripheral blood, as well as cervical lymph nodes. The allografts from animals treated with supCD28 MAb showed significantly less airway obliteration and rejection of the respiratory epithelium compared with allografts of the mouse immunoglobulin G-treated group on the 5th day and the 60th day after transplantation. Overall, our data demonstrated that an intraperitoneally administrated low dose of supCD28 MAb was sufficient to induce Treg cell expansion in vivo and was effective in protecting the airway graft from early rejection and chronic OAD development. These findings provide the basis for new therapies to prevent OAD and perhaps rejection of allografts in other human transplantations.

Myoblast transplantation improves cardiac function after myocardial infarction through attenuating inflammatory responses

Myocardial infarction (MI) is a highly prevalent cardiac emergency, which results in adverse cardiac remodeling and then exacerbates progressive heart failure. Inflammatory responses in cardiac tissue after MI is necessary for myocardium repair and wound healing. However, the excessive inflammation is also a key component of subsequent heart failure pathology. Myoblast transplantation after MI have been fulfilled attractive effects on cardiac repair, but the complications of transplantation and the underlying mechanisms have not been fully elucidated. Here, we found that human myoblast transplantation into minipig myocardium decreased the infiltration of inflammatory cells, the expression levels of many pro-inflammatory genes and the activation of inflammation-related signal pathways, while upregulated the expression levels of anti-inflammatory genes such as IL-10 in cardiac tissue of minipig post-MI, which was contributed to the improved cardiac function, the decreased infarct area and the attenuated myocardial fibrosis. Moreover, co-culture of human myoblasts inhibited the production of IL-1β and TNF-α as well as activation of MAPK and NF-κB signaling pathway induced by damage-associated molecular patterns such as HMGB1 and HSP60 in human THP-1 cells, which was partially attributed to the up-regulated production of IL-10. Collectively, these results indicate that myoblast transplantation ameliorates heart injury and improves cardiac function post-MI through inhibiting the inflammatory response, which provides the novel mechanism for myoblast transplantation therapy of MI.Myocardial infarction (MI) is a highly prevalent cardiac emergency, which results in adverse cardiac remodeling and then exacerbates progressive heart failure. Inflammatory responses in cardiac tissue after MI is necessary for myocardium repair and wound healing. However, the excessive inflammation is also a key component of subsequent heart failure pathology. Myoblast transplantation after MI have been fulfilled attractive effects on cardiac repair, but the complications of transplantation and the underlying mechanisms have not been fully elucidated. Here, we found that human myoblast transplantation into minipig myocardium decreased the infiltration of inflammatory cells, the expression levels of many pro-inflammatory genes and the activation of inflammation-related signal pathways, while upregulated the expression levels of anti-inflammatory genes such as IL-10 in cardiac tissue of minipig post-MI, which was contributed to the improved cardiac function, the decreased infarct area and the attenuated myocardial fibrosis. Moreover, co-culture of human myoblasts inhibited the production of IL-1β and TNF-α as well as activation of MAPK and NF-κB signaling pathway induced by damage-associated molecular patterns such as HMGB1 and HSP60 in human THP-1 cells, which was partially attributed to the up-regulated production of IL-10. Collectively, these results indicate that myoblast transplantation ameliorates heart injury and improves cardiac function post-MI through inhibiting the inflammatory response, which provides the novel mechanism for myoblast transplantation therapy of MI.