Recent advances in the diagnostic and therapeutic roles of microRNAs in colorectal cancer progression and metastasis.

Colorectal cancer (CRC) is the third most common malignancy in the world and one of the leading causes of cancer death; its incidence is still increasing in most countries. The early diagnostic accuracy of CRC is low, and the metastasis rate is high, resulting in a low survival rate of advanced patients. MicroRNAs (miRNAs) are a small class of noncoding RNAs that can inhibit mRNA translation and trigger mRNA degradation, and can affect a variety of cellular and molecular targets. Numerous studies have shown that miRNAs are related to tumour progression, immune system activity, anticancer drug resistance, and the tumour microenvironment. Dysregulation of miRNAs occurs in a variety of malignancies, including CRC. In this review, we summarize the recent research progress of miRNAs, their roles in tumour progression and metastasis, and their clinical value as potential biomarkers or therapeutic targets for CRC. Furthermore, we combined the roles of miRNAs in tumorigenesis and development with the therapeutic strategies of CRC patients, which will provide new ideas for the diagnosis and treatment of CRC.

Red fluorescent AIEgens based multifunctional nonviral gene vectors for the efficient combination of gene therapy and photodynamic therapy in anti-cancer.

Precise molecular engineering of AIEgens-based cationic delivery systems for high transfection efficiency (TE) and effective photodynamic therapy (PDT) holds a huge potential for cancer treatment. Herein, three amphiphiles (DT-C6/8/12-M) consisting of di(triazole-[12]aneN3) (M) and 1,1-dicyano-2-phenyl-2-(4-diphenylamino)phenyl-ethylene (DT) units have been developed to achieve luminescent tracking, efficient TE, and effective PDT in vitro and in vivo. These compounds exhibited strong aggregated induced emission (AIE) at 630 nm and mega Stokes shifts of up to 160 nm. They were able to bind DNA into nanoparticles with suitable sizes, positive surface potential, and good biocompatibility in the presence of DOPE. Among them, vector DT-C12-M/DOPE with n-dodecyl linker achieved a transfection efficiency as high as 42.3 folds that of Lipo2000 in PC-3 cell lines. DT-C12-M/DOPE exhibited the capability of successful endo/lysosomal escape and rapid nuclear delivery of pDNA, and the gene delivery process was clearly monitored via confocal laser scanning microscopy. Moreover, efficient reactive oxygen species (ROS) generation by DT-C12-M upon light irradiation led to effective PDT in vitro . We further show that combination of p53 gene therapy and PDT dramatically enhanced cancer therapeutic outcome in vivo. This "three birds, one stone" strategy offers a novel and promising approach for real-time tracking of gene delivery and better cancer treatment.

Highly water-dispersible PCN nanosheets as light-controlled lysosome self-promoting escape type non-cationic gene carriers for tumor therapy.

The construction of non-viral gene delivery faces two major challenges: cytotoxicity caused by high cationic charge units and easy degradation by lysosomes. Herein, highly water-dispersible polymeric carbon nitride (PCN) nanosheets were utilized as the core to construct a light-controlled non-cationic gene delivery system with sufficient lysosomal escape ability. In this system, these nanosheets exhibited efficient DNA condensation, outstanding biocompatibility, transfection tracking, light responsiveness and high transfection efficiency. Once PCN-DNA was taken up by the tumor cells, the accumulated ROS generated by photosensitizers (PSs) under light irradiation would destroy the structure of lysosomes, promote the escape of PCN-DNA and increase the efficiency of gene transfection. Simultaneously, the gene transfection process could be tracked in real time through fluorescence imaging technology, which was conducive to investigate the transfection mechanism. In vitro and in vivo experiments further confirmed that PCN nanosheets loaded with the P53 gene were beneficial to the regeneration of the P53 apoptotic pathway, increased tumor sensitivity to PSs, and further induced tumor cell apoptosis. In summary, the highly water-dispersible PCN nanosheets were applied to light-controlled self-escaping gene delivery for the first time, and tumor gene therapy was successfully realized.

Multifunctional amphiphilic peptide dendrimer as nonviral gene vectors for effective cancer therapy via combined gene/photodynamic therapies.

Gene therapy holds great promise for treatment of gene-associated diseases. However, safe and successful clinical application urgently requires further advancement of constructing efficient delivery systems. Herein, three amphiphilic peptide dendrimers (TTC-L-KRR/KKK/KHH), containing the natural amino acid residues (lysine K, arginine R, and histidine H) and AIE-based photosensitizer (tetraphenylethenethiophene modified cyanoacrylate, TTC) modified with alkyl chain (L), have been designed and prepared for improving therapeutic potency via the combination of gene therapy (GT) and photodynamic therapy (PDT). All three compounds possessed typical aggregation-induced emission (AIE) characteristics and ultralow critical micelle concentrations (CMCs). The liposomes consisting of amphiphilic peptide dendrimers and dioleoylphosphatidylethanolamine (DOPE) can effectively bind DNA into nanoparticles with appropriate sizes, regular morphology and good biocompatibility. Among them, liposomes TTC-L-KKK/DOPE exhibited the highest transfection efficiency up to 5.7-fold as compared with Lipo2000 in HeLa cells. Meanwhile, rapid endocytosis, successful endo/lysosomal escape, gene release and rapid nuclear delivery of DNA revealed the superiority of liposomes TTC-L-KKK/DOPE during gene delivery process. More importantly, efficient reactive oxygen species (ROS) generation by TTC-L-KKK/DOPE led to effective PDT, thus improving therapeutic potency via combining with p53 mediated-gene therapy. Our work brought novel insight and direction for the construction of bio-safe and bio-imaging liposome as the multifunctional nonviral gene vectors for the effective combined gene/photodynamic therapies.

[12]aneN3-Conjugated AIEgens with two-photon imaging properties for synergistic gene/photodynamic therapy in vitro and in vivo.

Six amphiphiles (TTC-L-M-1/2/3/4/5/6), each consisting of hydrophilic macrocyclic polyamine triazole-[12]aneN3 (M) and a hydrophobic photosensitizer tetraphenylethenethiophene modified cyanoacrylate (TTC) moiety linked with alkyl chains (L), have been designed and synthesized for synergetic anticancer gene therapy and photodynamic therapy (PDT). These amphiphiles showed strong AIE fluorescence emissions around 600 nm with large Stokes shifts up to 168 nm in an aqueous solution. They were able to condense DNA into nanoparticles with appropriate sizes, positive charges, reversible release, and good biocompatibility. Quantitative and qualitative gene transfection studies indicated that TTC-L-M-4 with a 12 carbon alkyl chain exhibited the best transfection efficiency in HeLa cells, and its transfection efficiency was 4.5-fold that of Lipo2000 in the presence of DOPE. The detailed and efficient delivery process of DNA by TTC-L-M-4 was clearly observed through one- and two-photon fluorescence imaging. Simultaneously, TTC-L-M-4/DOPE was able to deliver siRNA and gene silencing was better than that of Lipo2000. Furthermore, TTC-L-M-4 was able to efficiently generate reactive oxygen species (ROS) for PDT upon light irradiation. It was further demonstrated that combined p53 gene therapy and PDT significantly enhanced cancer therapy in vitro and in vivo. This study provides novel one-for-all organic agents with multiple therapeutic modalities.

Degradable cationic polyesters via ring-opening copolymerization of valerolactones as nanocarriers for the gene delivery.

The development of cationic polymers as non-viral gene vectors has been hurdled by their high toxicity, thus degradable and biocompatible polymers are urgently demanded. Herein, five polyesters (B3a-B3e) were synthesized based on the ring-opening copolymerization between α-allyl-δ-valerolactone and δ-valerolactone derivatives decorated with alkyl or alkoxyl chains of different lengths, followed by the modification with 1,5,9-triazacyclododecyl ([12]aneN3) through thiol-ene click reactions. The five polyesters effectively condensed DNA into nanoparticles. Of them, B3a with a shorter alkyl chain and B3d with more positive charged units showed stronger DNA condensing performance and can completely retard the migration of DNA at N/P = 1.6 in the presence of DOPE. B3b/DOPE with a longer alkyl chain exhibited the highest transfection efficiency in HeLa cells with 1.8 times of 25 kDa PEI, while B3d/DOPE with more positive charged units exhibited highest transfection efficiency in A549 cells with 2.3 times of 25 kDa PEI. B3b/DOPE and B3d/DOPE successfully delivered pEGFP into zebrafish, which was superior to 25 kDa PEI (1.5 folds and 1.1 folds, respectively). The cytotoxicity measurements proved that the biocompatibility of these polyesters was better than 25 kDa PEI, due to their degradable property in acid environment. The results indicated that these cationic polyesters can be developed as potential non-viral gene vectors for DNA delivery.

Integrative taxonomy reveals a new species of the genus Burmoniscus (Isopoda, Philosciidae) from the Xuefeng Mountains, China.

Three species of the genus Burmoniscus are identified from the Xuefeng Mountains, central China, by integrating morphological and molecular approaches. Burmoniscuschuanyanensis Li, sp. nov. is described. Morphological photographs of the new species are provided.

Integration of [12]aneN3 and Acenaphtho[1,2-b]quinoxaline as non-viral gene vectors with two-photon property for enhanced DNA/siRNA delivery and bioimaging.

Two-photon fluorescent Acenaphtho[1,2-b]quinoxaline (ANQ) and the hydrophilic di-(triazole-[12]aneN3) moieties were combined through an alkyl chain (ANQ-A-M) or a ß-hairpin motif with two aromatic γ-amino acid residues (ANQ-H-M) to explore their capabilities for in vitro and in vivo gene delivery and tracing. ANQ-A-M and ANQ-H-M showed the same maximum absorption at 420 nm, and their fluorescent intensities around 650 nm were varied in different solvents and became poor in the protic solvents. Gel electrophoresis assays indicated that both compounds completely retarded the migration of pDNA at 20 µM in the presence of DOPE. However, the DNA condensation with ANQ-H-M was not reversible, and the particle size of the corresponding complexes were larger indicated from the SEM and DLS measurements. In vitro transfections indicated ANQ-A-M/DOPE achieved Luciferase and GFP expressions were to be 7.9- and 5.7-fold of those by Lipo2000 in A549 cells respectively. However, ANQ-H-M showed very poor transfection efficiency in Luciferase expression. With the help of single/two-photon fluorescence imaging it clearly demonstrated that the successful transfection of ANQ-A-M was attributed to its cellular uptake, apparent lysosomal escape, and reversible release of DNA; and the poor transfection of ANQ-H-M was resulted from the aggregation of the DNA complexes which prevented them from the cellular uptake, and also the strong binding ability which is not easy to release DNA. ANQ-A-M/DOPE also exhibited robust gene silencing (83% knockdown of Luciferase) and GFP expression (2.47-fold higher) efficiency compared with Lipo2000 in A549 and zebrafish, respectively. The work demonstrated that the linkage structure between fluorescent and di(triazole-[12]aneN3) played the important role for their gene delivery performance, and that ANQ-A-M represents a vector with the strong transfection efficiency in vitro and in vivo as well as the efficient real time bioimaging properties, which is potential for the development in biomedical research.

LncRNA SNHG14 aggravates invasion and migration as ceRNA via regulating miR-656-3p/SIRT5 pathway in hepatocellular carcinoma.

Recurrence and adverse events after hepatocellular carcinoma (HCC) treatment occur frequently even treated with the most efficient therapy for HCC, liver transplantation. Therefore, better understanding of HCC progression is required to advance the therapeutic strategy of HCC. This study aims to explore the effect and mechanism of small nucleolar RNA host gene 14 (SNHG14) on HCC cell invasion and migration. SNHG14 and miR-656-3p expression in HCC tissues and cells were examined by qRT-PCR. After co-transfection with sh-SNHG14, miR-656-3p inhibitor, miR-656-3p mimic, si-SIRT5, pcDNA3.1-SIRT5 and corresponding negative controls, HepG2 and MHCC97H cell proliferation, invasion and migration were detected. Then the expression levels of SNHG14, miR-656-3p and SIRT5 were measured by qRT-PCR and Western blot. Luciferases reporter gene assay and RNA pull down identified the relation between SNHG14 and miR-656-3p and between miR-656-3p and SIRT5. SNHG14 was upregulated and miR-656-3p was downregulated in HCC cells. Inhibition of SNHG14 could inhibit HepG2 and MHCC97H cell proliferation, invasion and migration. Upregulation of miR-656-3p or knockdown of SIRT5 significantly suppressed the biological process of HepG2 and MHCC97H cells. SNHG14 directly acted on miR-656-3p and SIRT5 was a target gene of miR-656-3p. miR-656-3p inhibitor or pcDNA3.1-SIRT5 could reverse the inhibition of sh-SNHG14 on cell proliferation, invasion and migration of HCC cells. SNHG14 promotes HCC cell invasion and migration through regulating miR-656-3p/SIRT5 axis.

First record of the genus Tetracona Meyrick (Lepidoptera, Crambidae) from China, with description of a new species.

The genus Tetracona has two species with an Australian distribution. The present study aims to record the genus from China for the first time and to add a third species, T. multispina Jie & Li, sp. nov. to the genus. The new species can be distinguished from the congeners by the antemedial line connecting the postmedial line near the dorsum in the hindwing, and the phallus with a cluster of spine-like cornuti in the male genitalia. Images of the habitus, tympanal organs and male genitalia are provided for the new species.

The geographical distribution patterns of Chrysoteuchia Hübner in China and description of a new species (Lepidoptera, Crambidae).

The geographical distribution patterns of Chrysoteuchia Hübner in China are analysed with MaxEnt and ArcGIS based on known localities and nineteen environmental variables. The results suggest that southeastern China is a highly suitable area, and Bio11 (mean temperature of the coldest quarter), Bio12 (annual precipitation) and Bio18 (precipitation of the warmest quarter) are revealed to be the main variables affecting the present distribution patterns. Among them, Bio18 is the strongest predictor with a 24.3% contribution. Furthermore, a new species from Tibet is added to the genus, Chrysoteuchialandryi sp. nov., and the male of C.curvicavus is described for the first time. Images of adults and their genitalia are illustrated, and two maps showing the geographical distribution patterns of Chrysoteuchia in China are provided.

H2O2-responsive polymeric micelles with a benzil moiety for efficient DOX delivery and AIE imaging.

Nano drug delivery is a promising domain in biomedical theranostics and has aroused more and more attention in recent years. We report here an amphiphilic polymer TPG1, bearing a H2O2-sensitive benzil and an AIE fluorophore tetraphenylethene (TPE) unit, which is able to self-assemble into spherical nanosized micelles in aqueous solution. Doxorubicin (DOX) can be encapsulated into TPG1 micelles efficiently with the loading capability of up to 59% by weight. The benzil moiety could be cleaved via the Baeyer-Villiger type reaction in the presence of H2O2, leading to the decomposition of TPG1 micelles and release of DOX. In vitro studies indicated that DOX-loaded TPG1 micelles can be internalized by cancer cells, followed by unloading encapsulated DOX under the stimulation of H2O2. The drug release process can be monitored by the AIE fluorescence from the degradation products containing a TPE moiety. MTT assays against HeLa and HepG2 cancer cells demonstrated that DOX-loaded micelles showed good anticancer efficacy. The polymer TPG1 and the corresponding decomposed products showed great biocompatibility. Our data suggest that TPG1 has the potential to be employed for the controlled drug delivery system.

Aurora A Inhibition Eliminates Myeloid Cell-Mediated Immunosuppression and Enhances the Efficacy of Anti-PD-L1 Therapy in Breast Cancer.

The Aurora A inhibitor alisertib shows encouraging activities in clinical trials against advanced breast cancer. However, it remains unclear whether and how the inflammatory microenvironment is involved in its efficacy. Here, we demonstrated that inhibition of Aurora A directly reshaped the immune microenvironment through removal of tumor-promoting myeloid cells and enrichment of anticancer T lymphocytes, which established a tumor-suppressive microenvironment and significantly contributed to the regression of murine mammary tumors. Mechanistically, alisertib treatment triggered apoptosis in myeloid-derived suppressor cells (MDSC) and macrophages, resulting in their elimination from tumors. Furthermore, alisertib treatment disrupted the immunosuppressive functions of MDSC by inhibiting Stat3-mediated ROS production. These alterations led to significant increases of active CD8+ and CD4+ T lymphocytes, which efficiently inhibited the proliferation of tumor cells. Intriguingly, alisertib combined with PD-L1 blockade showed synergistic efficacy in the treatment of mammary tumors. These results detail the effects of Aurora A inhibition on the immune microenvironment and provide a novel chemo-immunotherapy strategy for advanced breast cancers. SIGNIFICANCE: These findings show that inhibition of Aurora A facilitates an anticancer immune microenvironment, which can suppress tumor progression and enhance anti-PD-L1 therapy in breast cancer.See related commentary by Rivoltini et al., p. 3169.

The CXC Chemokine Receptor 3 Inhibits Autoimmune Cholangitis via CD8+ T Cells but Promotes Colitis via CD4+ T Cells.

CXC chemokine receptor 3 (CXCR3), a receptor for the C-X-C motif chemokines (CXCL) CXCL9, CXCL10, and CXCL11, which not only plays a role in chemotaxis but also regulates differentiation and development of memory and effector T cell populations. Herein, we explored the function of CXCR3 in the modulation of different organ-specific autoimmune diseases in interleukin (IL)-2 receptor deficiency (CD25-/-) mice, a murine model for both cholangitis and colitis. We observed higher levels of CXCL9 and CXCL10 in the liver and colon and higher expression of CXCR3 on T cells of the CD25-/- mice compared with control animals. Deletion of CXCR3 resulted in enhanced liver inflammation but alleviated colitis. These changes in liver and colon pathology after CXCR3 deletion were associated with increased numbers of hepatic CD4+ and CD8+ T cells, in particular effector memory CD8+ T cells, as well as decreased T cells in mesenteric lymph nodes and colon lamina propria. In addition, increased interferon-γ response and decreased IL-17A response was observed in both liver and colon after CXCR3 deletion. CXCR3 modulated the functions of T cells involved in different autoimmune diseases, whereas the consequence of such modulation was organ-specific regarding to their effects on disease severity. Our findings emphasize the importance of extra caution in immunotherapy for organ-specific autoimmune diseases, as therapeutic interventions aiming at a target such as CXCR3 for certain disease could result in adverse effects in an unrelated organ.

Adaptive immune cells are necessary for the enhanced therapeutic effect of sorafenib-loaded nanoparticles.

Sorafenib is a kinase inhibitor approved for the treatment of primary kidney cancer, advanced primary liver cancer, and radioactive iodine resistant advanced thyroid carcinoma. However, sorafenib usually causes serious side effects, which limit its antitumor effect. Nanoparticle based drug delivery systems have been widely used to enhance the therapeutic effects and reduce the side effects of this drug by the enhanced permeability and retention (EPR) effect. Herein, to improve the therapeutic effect of sorafenib, we developed poly(ethylene glycol)-b-poly(lactic acid-co-glycolic acid) (PEG-PLGA) based nanoparticles by a dialysis method for sorafenib encapsulation. After intravenous injection of the sorafenib loaded nanoparticles (NPsorafenib), the tumor growth of mice bearing B16-F10, MC38 and LLC tumor was significantly inhibited. Meanwhile, the dose of sorafenib was reduced to one ninth and the side effects on the hematopoietic system and immune system were abrogated. More importantly, the tumor growth inhibition effect of NPsorafenib was dramatically reduced in B16-F10 bearing Rag1-/- mice which are adaptive immune cell defective, indicating that the antitumor effects of NPsorafenib are dependent on the adaptive immune cells. These results emphasize the indispensable role of the adaptive immune system in nano-drug mediated antitumor effects and the adaptive immune system should be considered as an important factor for clinical applications.

FoxO1 is a regulator of MHC-II expression and anti-tumor effect of tumor-associated macrophages.

Macrophages are a critical component in host immune responses against tumor. In this work we investigated the role of forkhead box O1 (FoxO1) in the transcriptional regulation in macrophages, which affects the anti-tumor functions of tumor-associated macrophages (TAMs). First, we showed that TAMs expressed reduced levels of FoxO1, which was associated with their protumoral M2 polarization state. The suppression of FoxO1 expression in TAM was induced by the hypoxic condition in the tumor microenviroment. Next, we confirmed that FoxO1 positively regulates MHC-II genes by binding to the promoter region of Ciita gene, the master activator of multiple MHC-II genes. Loss of FoxO1 in TAMs resulted in reduced MHC-II expression. Furthermore, we used FoxO1 conditional knockout mice to show that FoxO1 deficiency in myeloid cells exacerbates tumor growth. These results demonstrate that the protumoral property of TAMs is induced by the hypoxia-triggered FoxO1 deficiency, which could be a potential target of novel anti-tumor therapies.

A Mouse Model of Autoimmune Cholangitis via Syngeneic Bile Duct Protein Immunization.

Primary biliary cholangitis (PBC) is an autoimmune liver disease characterized by the destruction of interlobular biliary ductules, which progressively leads to cholestasis, hepatic fibrosis, cirrhosis, and eventually liver failure. Several mouse models have been used to clarify the pathogenesis of PBC and are generally considered reflective of an autoimmune cholangitis. Most models focus on issues of molecular mimicry between the E2 subunit of the pyruvate dehydrogenase complex (PDC-E2), the major mitochondrial autoantigen of PBC and xenobiotic cross reactive chemicals. None have focused on the classic models of breaking tolerance, namely immunization with self-tissue. Here, we report a novel mouse model of autoimmune cholangitis via immunization with syngeneic bile duct protein (BDP). Our results demonstrate that syngeneic bile duct antigens efficiently break immune tolerance of recipient mice, capturing several key features of PBC, including liver-specific inflammation focused on portal tract areas, increased number and activation state of CD4 and CD8 T cells in the liver and spleen. Furthermore, the germinal center (GC) responses in the spleen were more enhanced in our mouse model. Finally, these mice were 100% positive for anti-mitochondrial antibodies (AMAs). In conclusion, we developed a novel mouse model of PBC that may help to elucidate the detailed mechanism of this complex disease.

Modulation of liver regeneration via myeloid PTEN deficiency.

Molecular mechanisms that modulate liver regeneration are of critical importance for a number of hepatic disorders. Kupffer cells and natural killer (NK) cells are two cell subsets indispensable for liver regeneration. We have focused on these two populations and, in particular, the interplay between them. Importantly, we demonstrate that deletion of the myeloid phosphatase and tensin homolog on chromosome 10 (PTEN) leading to an M2-like polarization of Kupffer cells, which results in decreased activation of NK cells. In addition, PTEN-deficient Kupffer cells secrete additional factors that facilitate the proliferation of hepatocytes. In conclusion, PTEN is critical for inhibiting M2-like polarization of Kupffer cells after partial hepatectomy, resulting in NK cell activation and thus the inhibition of liver regeneration. Furthermore, PTEN reduces growth factor secretion by Kupffer cells. Our results suggest that targeting PTEN on Kupffer cells may be useful in altering liver regeneration in patients undergoing liver resection.

Tubeimoside-1 induces oxidative stress-mediated apoptosis and G0/G1 phase arrest in human prostate carcinoma cells in vitro.

AIM: Tubeimoside-1 (TBMS1), a triterpenoid saponin extracted from the Chinese herbal medicine Bolbostemma paniculatum (Maxim) Franquet (Cucurbitaceae), has shown anticancer activities in various cancer cell lines. The aim of this study was to investigate the anticancer activity and molecular targets of TBMS1 in human prostate cancer cells in vitro. METHODS: DU145 and P3 human prostate cancer cells were treated with TBMS1. Cell viability and apoptosis were detected. ROS generation, mitochondrial membrane potential and cell cycle profile were examined. Western blotting was used to measure the expression of relevant proteins in the cells. RESULTS: TBMS1 (5-100 µmol/L) significantly suppressed the viability of DU145 and P3 cells with IC50 values of approximately 10 and 20 µmol/L, respectively. Furthermore, TBMS1 dose-dependently induced apoptosis and cell cycle arrest at G0/G1 phase in DU145 and P3 cells. In DU145 cells, TBMS1 induced mitochondrial apoptosis, evidenced by ROS generation, mitochondrial dysfunction, endoplasmic reticulum stress, modulated Bcl-2 family protein and cleaved caspase-3, and activated ASK-1 and its downstream targets p38 and JNK. The G0/G1 phase arrest was linked to increased expression of p53 and p21 and decreased expression of cyclin E and cdk2. Co-treatment with Z-VAD-FMK (pan-caspase inhibitor) could attenuate TBMS1-induced apoptosis but did not prevent G0/G1 arrest. Moreover, co-treatment with NAC (ROS scavenger), SB203580 (p38 inhibitor), SP600125 (JNK inhibitor) or salubrinal (ER stress inhibitor) significantly attenuated TBMS1-induced apoptosis. CONCLUSION: TBMS1 induces oxidative stress-mediated apoptosis in DU145 human prostate cancer cells in vitro via the mitochondrial pathway.

Forkhead Box O1 Regulates Macrophage Polarization Following Staphylococcus aureus Infection: Experimental Murine Data and Review of the Literature.

The functions of macrophages that lead to effective host responses are critical for protection against Staphylococcus aureus. Deep tissue-invading S. aureus initially countered by macrophages trigger macrophage accumulation and induce inflammatory responses through surface receptors, especially toll-like receptor 2 (TLR2). Here, we found that macrophages formed sporadic aggregates in the liver during infection. Within those aggregates, macrophages co-localized with T cells and were indispensable for their infiltration. In addition, we have focused on the mechanisms underlying the polarization of macrophages in Forkhead box transcription factor O1 (FoxO1) conditional knockout Lys Cre/+ FoxO1 fl/fl mice following S. aureus infection and report herein that macrophage M1-M2 polarization via TLR2 is intrinsically regulated by FoxO1. Indeed, for effective FoxO1 activity, stimulation of TLR2 is essential. However, following S. aureus challenge, there was a decrease in macrophage FoxO1, with increased phosphorylation of FoxO1 because of TLR2-mediated activation of PI3K/Akt and c-Raf/MEK/ERK pathway. Following infection in Lys Cre/+ FoxO1 fl/fl mice, mice became more susceptible to S. aureus with reduced macrophage aggregation in the liver and attenuated Th1 and Th17 responses. FoxO1 abrogation reduced M1 pro-inflammatory responses triggered by S. aureus and enhanced M2 polarization in macrophages. In contrast, overexpression of FoxO1 in macrophages increased pro-inflammatory mediators and functional surface molecule expression. In conclusion, macrophage FoxO1 is critical to promote M1 polarization and maintain a competent T cell immune response against S. aureus infection in the liver. FoxO1 regulates macrophage M1-M2 polarization downstream of TLR2 dynamically through phosphorylation.