LAMP1 controls CXCL10-CXCR3 axis mediated inflammatory regulation of macrophage polarization during inflammatory stimulation.

Increased expression of CXCL10 and its receptor CXCR3 represents an inflammatory response in cells and tissues. Macrophage polarization and autophagy are major functions in inflammatory macrophages; however, the cellular functions of the CXCL10-CXCR3 axis in macrophages are not well understood. Here, we examined the role of CXCL10-CXCR3-axis-regulated autophagy in macrophage polarization. First, in non-inflammatory macrophages, whereas CXCL10 promotes M2 polarization and inhibits M1 polarization, CXCR3 antagonist AMG487 induces the opposite macrophage polarization. Next, CXCL10 promotes the expression of autophagy proteins (Atg5-Atg12 complex, p62, LC3-II, and LAMP1) and AMG487 inhibits their expression. Knockdown of LAMP1 by short interfering RNA switches the CXCL10-induced polarization from M2 to M1 in non-inflammatory macrophages. Furthermore, in inflammatory macrophages stimulated by poly(I:C), CXCL10 induces M1 polarization and AMG487 induces M2 polarization in association with a decrease in LAMP1. Finally, AMG487 alleviates lung injury after poly(I:C) treatment in mice. In conclusion, CXCL10-CXCR3 axis differentially directs macrophage polarization in inflammatory and non-inflammatory states, and autophagy protein LAMP1 acts as the switch controlling the direction of macrophage polarization by CXCL10-CXCR3.

AMG487 inhibits PRRSV replication and ameliorates lung injury in pig lung xenografts by down-regulating the expression of ANXA2.

Porcine reproductive and respiratory syndrome (PRRS) is a pig disease caused by the PRRS virus (PRRSV) that is characterized with diffuse interstitial pneumonia and lung edema. High expressions of chemokine CXCL10 and its receptor CXCR3 are reported in infected porcine lungs. Since CXCR3 is a key player in host inflammatory response, it might be a therapeutic target to treat lung damage caused by PRRSV infection. The size of pigs has long hampered research into molecular mechanisms of PRRS and validating the potential pharmaceutical targets. In this study, a porcine lung xenograft model with PRRSV infection was generated in immunodeficient mice to evaluate the therapeutic effects of the CXCR3 antagonist AMG487 on PRRSV infection-induced lung injury. The porcine lung tissues developed normally two weeks after xeno-transplantation in the mouse kidney capsule. Infection of PRRSV resulted in its efficient replication in the xenografts and histological damage to the porcine lung tissue structure, with no or little effects on mouse lungs. AMG487 administration dramatically reduced the number of PRRSV genome copies and significantly alleviated the porcine lung injury. Furthermore, treatment of AMG487 in cultured porcine macrophages consistently suppressed PRRSV replication with significant downregulation of Annexin A2 (ANXA2), a cellular protein facilitating viral replication. These findings provide a suitable model for evaluating new antiviral therapies as well as a possible therapeutic option for virus infection-induced lung injury.

Pharmacological Applications and Action Mechanisms of Phytochemicals as Alternatives to Antibiotics in Pig Production.

Antibiotics are widely used for infectious diseases and feed additives for animal health and growth. Antibiotic resistant caused by overuse of antibiotics poses a global health threat. It is urgent to choose safe and environment-friendly alternatives to antibiotics to promote the ecological sustainable development of the pig industry. Phytochemicals are characterized by little residue, no resistance, and minimal side effects and have been reported to improve animal health and growth performance in pigs, which may become a promising additive in pig production. This paper summarizes the biological functions of recent studies of phytochemicals on growth performance, metabolism, antioxidative capacity, gut microbiota, intestinal mucosa barrier, antiviral, antimicrobial, immunomodulatory, detoxification of mycotoxins, as well as their action mechanisms in pig production. The review may provide the theoretical basis for the application of phytochemicals functioning as alternative antibiotic additives in the pig industry.

The tissue specific regulation of miR22 expression in the lung and brain by ribosomal protein L29.

Endogenous miR22 is associated with a diverse range of biological processes through post-translational modification of gene expression and its deregulation results in various diseases including cancer. Its expression is usually tissue or cell-specific, however, the reasons behind this tissue or cell specificity are not clearly outlined till-date. Therefore, our keen interest was to investigate the mechanisms of tissue or cell-specific expression of miR22. In the current study, miR22 expression showed a tissues-specific difference in the poly(I:C) induced inflammatory mouse lung and brain tissues. The cell-specific different expression of miR22 was also observed in inflammatory glial cells and endothelial cells. The pattern of RPL29 expression was also similar to miR22 in these tissues and cells under the same treatment. Interestingly, the knockdown of RPL29 exerted an inhibitory effect on miR22 and its known transcription factors including Fos-B and c-Fos. Fos-B and c-Fos were also differentially expressed in the two cell lines transfected with poly(I:C). The knockdown of c-Fos also exerted its negative effects on miR22 expression in both cells. These findings suggest that RPL29 might have regulatory roles on tissue or cell-specific expression of miR22 through the transcription activities of c-Fos and also possibly through Fos-B.

Higher expression levels of aquaporin (AQP)1 and AQP5 in the lungs of arid-desert living Lepus yarkandensis.

Water transport across epithelial cells that line the airways and alveoli is a crucial component of lung physiology. Aquaporins (AQPs) facilitate water transport across the air space-capillary barrier in the distal lung. However, the roles of lung AQPs in desert animal adaptation to dry airstream environments are still unclear. A hare (Lepus yarkandensis) only lives in the Tarim Basin, and its living environment is an arid climate with rare precipitation. We studied cellular localization and expression levels of AQP1, AQP3, AQP4 and AQP5 in L. yarkandensis lungs by immunohistochemistry, quantitative real-time polymerase chain reaction and Western blot. The lung of rabbits (Oryctolagus cuniculus) that inhabit in mesic environment was similarly studied. Obtained results in two species of animals were compared to investigate whether AQPs in the lung altered expression in the animal living in arid region. AQP1 was localized to the endothelial cells in capillaries and venules surrounding terminal bronchioles and alveoli. AQP5 was localized to the ciliated columnar cells in terminal bronchioles and the alveolar type I cells in the alveolus. Quantitative real-time PCR analysis showed higher AQP1 and AQP5 mRNA levels in L. yarkandensis compared to O. cuniculus. Similar results were obtained by Western blot. These results revealed that the higher expression levels of AQP1 and AQP5 played a significant role in water transport in the lungs of arid-desert living L. yarkandensis and might accelerate water transport from capillary compartments to the airspace.

SIRT1/PGC-1 pathway activation triggers autophagy/mitophagy and attenuates oxidative damage in intestinal epithelial cells.

Oxidative stress leads to intestinal epithelial cells damage, which induces tight junction injury and systemic endogenous stress syndrome. The evidence suggests that SIRT1/PGC-1α pathway is closely associated with oxidative damage. However, the mechanism in protecting intestinal epithelial cells against oxidative stress dependant on autopahgy/mitophagy remains to be elucidated. In the current study, we investigated the functional role of SIRT1/PGC-1α pathway on regulation of autopahgy/mitophagy and tight junction protein expression underlying the oxidative dysfunction in porcine intestinal epithelial cells (IPEC-1). Results demonstrated that H2O2 exposure caused high accumulation of ROS, with a decrease of mitochondrial membrane potential and an inhibition of the tight junction molecules in IPEC-1 cells. Also, COX IV mRNA expression and SIRT1/PGC-1α pathway were suppressed. Autophagy and PINK1/Parkin dependant-mitophagy were activated following H2O2 treatment. Further research indicated that activation of SIRT1/PGC-1α pathway caused by specific activator SRT 1720 resulted in elevating autophagy/mitophagy related markers and SIRT1 inhibitor EX 527 reversed these effects. Additionally, SIRT1 activation significantly suppressed the ROS generation, leading to increase mitochondrial membrane potential and COX IV expression. Most importantly, the expression of tight junction molecules contributing to maintain intestinal barrier integrity was significantly up-regulated. Collectively, these findings indicated that autophagy/mitophagy elevation caused by SIRT1/PGC-1α pathway activation might be a protective mechanism to increase tight junction integrity against oxidative stress-mediated ROS production in IPEC-1 cells.

Knockdown of long noncoding RNA urothelial carcinoma associated 1 inhibits colorectal cancer cell proliferation and promotes apoptosis via modulating autophagy.

Long noncoding RNA urothelial carcinoma associated 1 (UCA1) has been implicated in the growth and metastasis of colorectal cancer (CRC), and autophagy contributes to tumorigenesis and cancer cell survival. However, the regulatory role of UCA1 in CRC cell viability by modulating autophagy remains unclear. In the present study, a significant positive correlation was observed between UCA1 and microtubule-associated protein 1 light chain 3 (LC3) levels, and the elevated UCA1 was negatively correlated with the PKB/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway in 293T cells. Downregulation of UCA1 inhibited autophagy activation and cell proliferation, whereas the apoptosis was increased and the cell cycle was arrested in G2 stage. The next results showed that UCA1 was markedly upregulated in Caco-2 cells. Knockdown of UCA1 significantly decreased the LC3-II and autophagy-related gene 5 (ATG5) protein levels and resulted in an increase in p62 expression. Conversely, the autophagy activator rapamycin (RAPA) reversed the effects. Furthermore, downregulated UCA1 decreased Caco-2 cells population in the G1 phase and increased the cells number in G2 phage. The cell proliferation was inhibited, and apoptosis rate was promoted. More important, RAPA could also abrogate the changes induced by knockdown of UCA1. Collectively, these data demonstrated that downregulated UCA1 induced autophagy inhibition, resulting in suppressing cell proliferation and promoting apoptosis, which suggested that UCA1 might serve as a potential new oncogene to regulate CRC cells viability by modulating autophagy.

Knockdown of Long Non-Coding RNA GAS5 Increases miR-23a by Targeting ATG3 Involved in Autophagy and Cell Viability.

BACKGROUND/AIMS: Autophagy is a process of evolutionarily conservative degradation, which could maintain cellular homeostasis and cope with various types of stress. LncRNAs are considered as competing endogenous RNAs (ceRNAs) contributing to autophagy. GAS5 has been suggested as a new potential factor to mediate autophagy pathway and the underlying mechanism remains to be further confirmed. This study was taken to identify the effect of GAS5/miR-23a/ATG3 axis on autophagy and cell viability. METHODS: The western blotting assay was used to detecte the protein levels of LC3, mTOR, Beclin-1, ATG3, ATG5-ATG12 complex and p62. The mRNA level of Pre-miR-23a, Pri-miR-23a, miR-23a, GAS5, LC3, mTOR and ATG3 were quantified by real-time RT-PCR. Dual-luciferase reporter assays were performed to confirm the direct binding of miR-23a and ATG3 or GAS5. Cell viability was evaluated by CCK-8 and flow cytometry. RESULTS: We showed that miR-23a could directly suppress ATG3 expression in 293T cells, which suggested that ATG3 was identified as a target of miR-23a. MiR-23a mimics could restrain LC3 II, Beclin1 levles and ATG5-ATG12 complex formation. Meanwhile, miR-23a also increased the expression of mTOR and p62. Notably, there was a putative miR-23a-binding site in GAS5. MiR-23a overexpression might suppress the GAS5 expression, but the repressive effect was abolished by mutation of binding sites. Importantly, overexpression of GAS5 could inhibit the mature miR-23a and has no effect on miR-23a precursors. Knockdown of GAS5 suppressed the expression of LC3 II, ATG3 and ATG5-ATG12 complex formation, whereas p62 and mTOR levels were promoted. The further results showed that miR-23a overexpression and GAS5 inhibition both significantly suppressed cell viability and promoted the apoptosis rate following LPS stimulation, and knockdown of miR-23a exhibited the opposite effects. CONCLUSIONS: Our study revealed that down-regulation GAS5 attenuated cell viability and inhibited autophagy through ATG3-dependent autophagy by regulating miR-23a expression. The results suggested that GAS5/miR-23a/ATG3 axis might be a novel regulatory network contributing to a better understanding of regulation on autophagy program and cell viability.

Downregulation of Aquaporins (AQP1 and AQP5) and Na,K-ATPase in Porcine Reproductive and Respiratory Syndrome Virus-Infected Pig Lungs.

Aquaporins (AQPs) and Na,K-ATPase control water transport across the air space-capillary barrier in the distal lung and play an important role in the formation and resolution of lung edema. Porcine reproductive and respiratory syndrome virus (PRRSV) infection usually causes pulmonary inflammation and edema in the infected pig lungs. To investigate the possibility that PRRSV infection may cause altered expression of AQPs and Na,K-ATPase messenger RNA (mRNA) levels and protein expression of AQP1, AQP5, and Na,K-ATPase in the PRRSV-infected pig lungs were detected. Quantitative real-time PCR (qRT-PCR) analysis showed markedly decreased mRNA levels of AQP1 and AQP5 and Na,K-ATPase in the PRRSV-infected pig lungs compared to those of uninfected pig lungs. Western blot studies also revealed significantly reduced levels of AQP1, AQP5, and Na,K-ATPase proteins in the PRRSV-infected pig lungs. In addition, immunohistochemical (IHC) analysis showed decreased protein expression of AQP1 and AQP5 in the endothelial cells of the capillaries and venules and secretory cells of terminal bronchiole and the alveolar type I cells, respectively. The expression of Na,K-ATPase in the basolateral membrane of alveolar type II cells presented great reduction in the PRRSV-infected pig lungs. To further understand the reduction of these proteins, the ubiquitination of AQP1 and Na,K-ATPase was examined in uninfected and PRRSV-infected pig lungs. The results showed that there is no difference of ubiquitination for these proteins. Thus, our results suggest that PRRSV infection may induce downregulation of these proteins and cause impairment of edema resolution by failed water clearance in the infected pig lungs.

Comparative Proteomics Analyses of Pollination Response in Endangered Orchid Species Dendrobium Chrysanthum.

Pollination is a crucial stage in plant reproductive process. The self-compatibility (SC) and self-incompatibility (SI) mechanisms determined the plant genetic diversity and species survival. D. chrysanthum is a highly valued ornamental and traditional herbal orchid in Asia but has been declared endangered. The sexual reproduction in D. chrysanthum relies on the compatibility of pollination. To provide a better understanding of the mechanism of pollination, the differentially expressed proteins (DEP) between the self-pollination (SP) and cross-pollination (CP) pistil of D. chrysanthum were investigated using proteomic approaches-two-dimensional electrophoresis (2-DE) coupled with tandem mass spectrometry technique. A total of 54 DEP spots were identified in the two-dimensional electrophoresis (2-DE) maps between the SP and CP. Gene ontology analysis revealed an array of proteins belonging to following different functional categories: metabolic process (8.94%), response to stimulus (5.69%), biosynthetic process (4.07%), protein folding (3.25%) and transport (3.25%). Identification of these DEPs at the early response stage of pollination will hopefully provide new insights in the mechanism of pollination response and help for the conservation of the orchid species.

ICAM-1 regulates macrophage polarization by suppressing MCP-1 expression via miR-124 upregulation.

Intercellular adhesion molecule-1 is the adhesion molecule mediating leukocyte firm adhesion to endothelial cells, plays a critical role in subsequent leukocyte transmigration. ICAM-1 is also expressed in other cells including macrophages; however, the role of this adhesion molecule in mediating macrophage functions remains enigmatic. We report that ICAM-1 regulates macrophage polarization by positively modulating miR-124 expression. We found higher expression levels of monocyte chemotactic protein-1 in lungs of mice lacking ICAM-1. Consistent with this result, siRNA mediated depletion of ICAM-1 in macrophage resulted in increased expression levels of MCP-1. Moreover, ICAM-1 controlled miR-124 expression and downregulated MCP-1 mRNA and protein expression by binding of miR-124 to MCP-1 3' untranslated region. ICAM-1 also induced the transcription factor Sp1 expression, which is important for miR-124 expressing in macrophages. Furthermore, ICAM-1 depletion led to M1 macrophage polarization, in contrast, miR-124 mimics promoted M2 macrophage polarization. Exogenous administration of miR-124 mimics into the lungs prevented lipopolysaccharide-induced myeloperoxidase activity in vivo, suggesting that miR-124 is important for dampening acute lung injury. These results collectively show that adhesion molecule ICAM-1 downregulates MCP-1 expression by controlling Sp1 mediated miR-124 levels, which in turn regulate M2 macrophage polarization. Targeting ICAM-1 and downstream miR-124 may present a new therapeutic strategy for acute lung injury.

MicroRNA-322 inhibits inflammatory cytokine expression and promotes cell proliferation in LPS-stimulated murine macrophages by targeting NF-κB1 (p50).

Inflammation is the body's normal self-protection mechanism to eliminate pathogens and resist pathogen invasion. The excessive inflammatory response may lead to inflammatory lesions. The mechanisms accounting for inflammation remain hazy. miRNAs have been proposed to have crucial effects on inflammation. In the present study, we reported that lipopolysaccharide (LPS)-stimulation increased the expression levels of inflammatory cytokines and the cell-cycle progression was suppressed in RAW264.7 cells. Meanwhile, the expression of miR-322 was significantly down-regulated after LPS treatment. Bioinformatics predictions revealed a potential binding site of miR-322 in 3'-UTR of NF-κB1 (p50) and it was further confirmed by luciferase assay. Moreover, both the mRNA and protein levels of NF-κB1 (p50) were down-regulated by miR-322 in RAW264.7 cells. Subsequently, we demonstrated that miR-322 mimics decrease in the expression levels of inflammatory cytokines and cell-cycle repression can be rescued following LPS treatment in RAW264.7 cells. The anti-inflammatory cytokines expression including IL-4 and IL-10 were significantly up-regulated. Furthermore, miR-322 could also promote RAW264.7 cells proliferation. These results demonstrate that miR-322 is a negative regulator of inflammatory response by targeting NF-κB1 (p50).