FAT4 overexpression promotes antitumor immunity by regulating the ß-catenin/STT3/PD-L1 axis in cervical cancer.

BACKGROUND: FAT4 (FAT Atypical Cadherin 4) is a member of the cadherin-associated protein family, which has been shown to function as a tumor suppressor by inhibiting proliferation and metastasis. The Wnt/ß-catenin pathway activation is highly associated with PD-L1-associated tumor immune escape. Here, we report the mechanism by which FAT4 overexpression regulates anti-tumor immunity in cervical cancer by inhibiting PD-L1 N-glycosylation and cell membrane localization in a ß-catenin-dependent manner. METHODS: FAT4 expression was first detected in cervical cancer tissues and cell lines. Cell proliferation, clone formation, and immunofluorescence were used to determine the tumor suppressive impact of FAT4 overexpression in vitro, and the findings were confirmed in immunodeficient and immunocomplete mice xenografts. Through functional and mechanistic experiments in vivo and in vitro, we investigated how FAT4 overexpression affects the antitumor immunity via the ß-catenin/STT3/PD-L1 axis. RESULTS: FAT4 is downregulated in cervical cancer tissues and cell lines. We determined that FAT4 binds to ß-catenin and antagonizes its nuclear localization, promotes phosphorylation and degradation of ß-catenin by the degradation complexes (AXIN1, APC, GSK3ß, CK1). FAT4 overexpression decreases programmed death-ligand 1 (PD-L1) mRNA expression at the transcriptional level, and causes aberrant glycosylation of PD-L1 via STT3A at the post-translational modifications (PTMs) level, leading to its endoplasmic reticulum (ER) accumulation and polyubiquitination-dependent degradation. We found that FAT4 overexpression promotes aberrant PD-L1 glycosylation and degradation in a ß-catenin-dependent manner, thereby increasing cytotoxic T lymphocyte (CTL) activity in immunoreactive mouse models. CONCLUSIONS: These findings address the basis of Wnt/ß-catenin pathway activation in cervical cancer and provide combination immunotherapy options for targeting the FAT4/ß-catenin/STT3/PD-L1 axis. Schematic cartoons showing the antitumor immunity mechanism of FAT4. (left) when Wnts bind to their receptors, which are made up of Frizzled proteins and LRP5/6, the cytoplasmic protein DVL is activated, inducing the aggregation of degradation complexes (AXIN, GSK3ß, CK1, APC) to the receptor. Subsequently, stable ß-catenin translocates into the nucleus and binds to TCF/LEF and TCF7L2 transcription factors, leading to target genes transcription. The catalytically active subunit of oligosaccharyltransferase, STT3A, enhances PD-L1 glycosylation, and N-glycosylated PD-L1 translocates to the cell membrane via the ER-to-Golgi pathway, resulting in immune evasion. (Right) FAT4 exerts antitumor immunity mainly through following mechanisms: (i) FAT4 binds to ß-catenin and antagonizes its nuclear localization, promotes phosphorylation and degradation of ß-catenin by the degradation complexes (AXIN1, APC, GSK3ß, CK1); (ii) FAT4 inhibits PD-L1 and STT3A transcription in a ß-catenin-dependent manner and induces aberrant PD-L1 glycosylation and ubiquitination-dependent degradation; (iii) Promotes activation of cytotoxic T lymphocytes (CTL) and infiltration into the tumor microenvironment.

Biomaterials-enhanced bioactive agents to efficiently block spinal metastases of cancers.

The spine is the most common site of bone metastases, as 20%-40% of cancer patients suffer from spinal metastases. Treatments for spinal metastases are scarce and palliative, primarily aiming at relieving bone pain and preserving neurological function. The bioactive agents-mediated therapies are the most effective modalities for treating spinal metastases because they achieve systematic and specific tumor regression. However, the clinical applications of some bioactive agents are limited due to the lack of targeting capabilities, severe side effects, and vulnerability of drug resistance. Fortunately, advanced biomaterials have been developed as excipients to enhance these treatments, including chemotherapy, phototherapy, magnetic hyperthermia therapy, and combination therapy, by improving tumor targeting and enabling sustaining and stimuli-responsive release of various therapeutic agents. Herein, the review summarizes the development of biomaterials-mediated bioactive agents for enhanced treatments of spinal metastases and predicts future research trends.

Airborne fine particles drive H1N1 viruses deep into the lower respiratory tract and distant organs.

Mounting data suggest that environmental pollution due to airborne fine particles (AFPs) increases the occurrence and severity of respiratory virus infection in humans. However, it is unclear whether and how interactions with AFPs alter viral infection and distribution. We report synergetic effects between various AFPs and the H1N1 virus, regulated by physicochemical properties of the AFPs. Unlike infection caused by virus alone, AFPs facilitated the internalization of virus through a receptor-independent pathway. Moreover, AFPs promoted the budding and dispersal of progeny virions, likely mediated by lipid rafts in the host plasma membrane. Infected animal models demonstrated that AFPs favored penetration of the H1N1 virus into the distal lung, and its translocation into extrapulmonary organs including the liver, spleen, and kidney, thus causing severe local and systemic disorders. Our findings revealed a key role of AFPs in driving viral infection throughout the respiratory tract and beyond. These insights entail stronger air quality management and air pollution reduction policies.

UBL7 enhances antiviral innate immunity by promoting Lys27-linked polyubiquitination of MAVS.

RNA virus infection usually triggers a range of host immune responses, including the induction of proinflammatory cytokines, interferons, and interferon-stimulated genes (ISGs). Here, we report that UBL7, a ubiquitin-like protein, is upregulated during RNA virus infection and induced by type I interferon as an ISG. UBL7-deficient mice exhibit increased susceptibility to viral infection due to attenuated antiviral innate immunity. UBL7 enhances innate immune response to viral infection by promoting the K27-linked polyubiquitination of MAVS. UBL7 interacts with TRIM21, an E3 ubiquitin ligase of MAVS, and promotes the combination of TRIM21 with MAVS in a dose-dependent manner, facilitating the K27-linked polyubiquitination of MAVS and recruiting of TBK1 to enhance the IFN signaling pathway. Moreover, UBL7 has a broad-spectrum antiviral function as an immunomodulatory adaptor protein. Therefore, UBL7 positively regulates innate antiviral signaling and promotes positive feedback to enhance and amplify the antiviral response.

Clostridium butyricum Prevents Dysbiosis and the Rise in Blood Pressure in Spontaneously Hypertensive Rats.

Hypertension is accompanied by dysbiosis and a decrease in the relative abundance of short-chain fatty acid (SCFA)-producing bacteria. However, there is no report to examine the role of C. butyricum in blood pressure regulation. We hypothesized that a decrease in the relative abundance of SCFA-producing bacteria in the gut was the cause of spontaneously hypertensive rats (SHR)-induced hypertension. C. butyricum and captopril were used to treat adult SHR for six weeks. C. butyricum modulated SHR-induced dysbiosis and significantly reduced systolic blood pressure (SBP) in SHR (p < 0.01). A 16S rRNA analysis determined changes in the relative abundance of the mainly SCFA-producing bacteria Akkermansia muciniphila, Lactobacillus amylovorus, and Agthobacter rectalis, which increased significantly. Total SCFAs, and particularly butyrate concentrations, in the SHR cecum and plasma were reduced (p < 0.05), while C. butyricum prevented this effect. Likewise, we supplemented SHR with butyrate for six weeks. We analyzed the flora composition, cecum SCFA concentration, and inflammatory response. The results showed that butyrate prevented SHR-induced hypertension and inflammation, and the decline of cecum SCFA concentrations (p < 0.05). This research revealed that increasing cecum butyrate concentrations by probiotics, or direct butyrate supplementation, prevented the adverse effects of SHR on intestinal flora, vascular, and blood pressure.

SARS-CoV-2 ORF10 impairs cilia by enhancing CUL2ZYG11B activity.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causal pathogen of the ongoing global pandemic of coronavirus disease 2019 (COVID-19). Loss of smell and taste are symptoms of COVID-19, and may be related to cilia dysfunction. Here, we found that the SARS-CoV-2 ORF10 increases the overall E3 ligase activity of the CUL2ZYG11B complex by interacting with ZYG11B. Enhanced CUL2ZYG11B activity by ORF10 causes increased ubiquitination and subsequent proteasome-mediated degradation of an intraflagellar transport (IFT) complex B protein, IFT46, thereby impairing both cilia biogenesis and maintenance. Further, we show that exposure of the respiratory tract of hACE2 mice to SARS-CoV-2 or SARS-CoV-2 ORF10 alone results in cilia-dysfunction-related phenotypes, and the ORF10 expression in primary human nasal epithelial cells (HNECs) also caused a rapid loss of the ciliary layer. Our study demonstrates how SARS-CoV-2 ORF10 hijacks CUL2ZYG11B to eliminate IFT46 and leads to cilia dysfunction, thereby offering a powerful etiopathological explanation for how SARS-CoV-2 causes multiple cilia-dysfunction-related symptoms specific to COVID-19.

Legionella pneumophila Risk from Cooling Tower Systems in China.

Legionella pneumophila widely exists in natural and artificial water environments, which enables it to infect people. L. pneumophila infection causes Legionnaires' disease (LD), which is a significant but relatively uncommon respiratory infection. Approximately 90% of LD is caused by L. pneumophila serogroup 1 (Lp1). Meteorological conditions may affect the infectivity and virulence of Lp1, but the exact relationship between them is still unclear. In this study, we evaluated the virulence of Lp1 by screening of total 156 Lp1 strains isolated from cooling tower water in different regions of China by detecting their abilities to activate NF-κB signaling pathway in vitro. In addition, we screened the distribution of some selected virulence genes in these strains. The virulence, virulence gene distribution, and the meteorological factors were analyzed. We found that both the virulence and the distribution of virulence genes had a certain regional and meteorological correlation. Although the loss of several virulence genes showed significant effects on the virulence of Lp1 strains, the distribution of virulence genes had very limited effects on the virulence of Lp1. IMPORTANCE LD is likely to be underrecognized in many countries. Due to the widespread existence of L. pneumophila in natural and artificial water environments and to the lack of cross-protection against different strains, L. pneumophila is a potentially serious threat to human health. Therefore, effective monitoring of the virulence of L. pneumophila in the water environment is very important to prevent and control the prevalence of LD. Understanding the virulence of L. pneumophila can not only help us to predict the risk of possible outbreaks in advance but can also enable more targeted clinical treatment. This study highlights the importance of understanding the epidemiology and ecology of L. pneumophila isolated from public facilities in terms of public health and biology. Due to the potential for water sources to harbor and disseminate L. pneumophila and to the fact that geographical conditions influence the virulence of L. pneumophila, timely and accurate L. pneumophila virulence surveillance is urgently needed.

Molecular mechanisms of long noncoding RNAs associated with cervical cancer radiosensitivity.

Despite advances in cervical cancer screening and human papilloma virus (HPV) vaccines, cervical cancer remains a global health burden. The standard treatment of cervical cancer includes surgery, radiation therapy, and chemotherapy. Radiotherapy (RT) is the primary treatment for advanced-stage disease. However, due to radioresistance, most patients in the advanced stage have an adverse outcome. Recent studies have shown that long noncoding RNAs (lncRNAs) participate in the regulation of cancer radiosensitivity by regulating DNA damage repair, apoptosis, cancer stem cells (CSCs), and epithelial-mesenchymal transition (EMT). In this review, we summarize the molecular mechanisms of long noncoding RNAs in cervical cancer and radiosensitivity, hoping to provide a theoretical basis and a new molecular target for the cervical cancer RT in the clinic.

Colonization of Clostridium butyricum in Rats and Its Effect on Intestinal Microbial Composition.

Gut microorganisms participate in many physiological processes. In particular, Clostridium butyricum can modulate gut microorganisms and treat diseases. The colonization and persistence of strains in the gut contribute to beneficial effects, and the colonization by C. butyricum in the gut is currently unknown. We investigated the total intestinal contents of C. butyricum at 12 h, 24 h, 48 h, and four and six days using real-time reverse transcription-PCR, after oral administration of C. butyricum to rats for seven consecutive days. We assessed the bacterial community structure using Illumina MiSeq sequencing. The results showed that C. butyricum was mainly colonized in the colon. The total content of C. butyricum in the gut increased significantly at 12 h after administration. Exogenous C. butyricum could still be detected in the gut six days after administration. Administration of C. butyricum significantly enhanced gut microbial diversity. The relative abundance of short-chain fatty acid-producing bacterial genera was shown to be higher than that of the control group, and treatment with C. butyricum elevated Firmicutes and diminished Bacteroidetes phyla compared with to the control group. These findings laid the foundation for the study of probiotic colonization capacity and the improvement of microflora for the prevention of gut diseases.

Declined miR-181a-5p expression is associated with impaired natural killer cell development and function with aging.

MicroRNAs (miRNAs) regulate gene expression and thereby influence cell development and function. Numerous studies have shown the significant roles of miRNAs in regulating immune cells including natural killer (NK) cells. However, little is known about the role of miRNAs in NK cells with aging. We previously demonstrated that the aged C57BL/6 mice have significantly decreased proportion of mature (CD27- CD11b+ ) NK cells compared with young mice, indicating impaired maturation of NK cells with aging. Here, we performed deep sequencing of CD27+ NK cells from young and aged mice. Profiling of the miRNome (global miRNA expression levels) revealed that 49 miRNAs displayed a twofold or greater difference in expression between young and aged NK cells. Among these, 30 miRNAs were upregulated and 19 miRNAs were downregulated in the aged NK cells. We found that the expression level of miR-l8la-5p was increased with the maturation of NK cells, and significantly decreased in NK cells from the aged mice. Knockdown of miR-181a-5p inhibited NK cell development in vitro and in vivo. Furthermore, miR-181a-5p is highly conserved in mice and human. MiR-181a-5p promoted the production of IFN-γ and cytotoxicity in stimulated NK cells from both mice and human. Importantly, miR-181a-5p level markedly decreased in NK cells from PBMC of elderly people. Thus, our results demonstrated that the miRNAs profiles in NK cells change with aging, the decreased level of miR-181a-5p contributes to the defective NK cell development and function with aging. This opens new strategies to preserve or restore NK cell function in the elderly.

Influenza virus matrix protein M1 interacts with SLD5 to block host cell cycle.

Influenza virus matrix 1 protein (M1) is highly conserved and plays essential roles at many stages of virus life cycle. Here, we used a yeast two-hybrid system to identify the host protein SLD5, a component of the GINS complex, which is essential for the initiation of DNA replication in eukaryotic cells, as a new M1 interacting protein. M1 from several different influenza virus strains all interacted with SLD5. Overexpression of SLD5 suppressed influenza virus replication. Transient, stable, or inducible expression of M1 induced host cell cycle blockade at G0/G1 phase. Moreover, SLD5 partially rescued M1 expression- or influenza virus infection-induced G0/G1 phase accumulation in cell lines and primary mouse embryonic fibroblasts. Importantly, SLD5 transgenic mice exhibited higher resistance and improved lung epithelial regeneration after virus infection compared with wild-type mice. Therefore, influenza virus M1 blocks host cell cycle process by interacting with SLD5. Our finding reveals the multifunctional nature of M1 and provides new insight for understanding influenza virus-host interaction.

The virulence of Legionella pneumophila is positively correlated with its ability to stimulate NF-κB activation.

AIM: Our work is to study the correlation between the virulence of different Legionella pneumophila in mouse model and its ability to activate NF-κB signaling pathway in vitro. MATERIALS & METHODS: We measured the abilities of different strains of L. pneumophila to induce the activation of NF-κB signaling pathway in vitro. By using A/J mice, we also detected the virulence of different strains in vivo. RESULTS & CONCLUSION: We demonstrated that different strains of L. pneumophila induce different levels of activation to NF-κB signaling pathway in vitro. We also found that L. pneumophila strain induced higher NF-κB activation in vitro showed more severe weight losses, higher mortality, more severe lung inflammation and higher levels of serum cytokines production in mice.

Aged Mice are More Resistant to Influenza Virus Infection due to Reduced Inflammation and Lung Pathology.

Immune responses are a double-edged sword. Effective and appropriate immune responses capable of controlling viral infection while also largely preserving tissue integrity, are critical for host survival. Too strong immune responses might result in immune pathology, while too weak immune responses might cause viral persistence. Physiologic ageing is accompanied with a decline in the normal functioning of the immune system, which is termed as "immunosenescence". We show that aged mice (16-19 months old) are more resistant to influenza A virus (IAV) infection than the young mice. Strong immune responses in the young mice after IAV infection result in faster clearance of virus, but also cause severe lung injury and higher mortality rate. While in the aged mice, the delayed and milder immune responses contribute to reduced pulmonary damage, and are still capable to clear the infection even with a slower kinetics, displaying a more resistant phenotype during IAV infection. Hence, our work demonstrates that moderate immune responses as a decline with ageing in the aged mice balance the immune pathology and viral clearance, might be beneficial for the host during certain circumstances. Our results provide important insight to our basic knowledge of immunosenescence and immune defenses to invading pathogens. Further, our results indicate that age factors should be considered when investigating the vaccination and therapeutic strategies for severe IAV infection.

The AP-1 transcription factor JunB is required for Th17 cell differentiation.

Interleukin (IL)-17-producing T helper (Th17) cells are crucial for host defense against extracellular microbes and pathogenesis of autoimmune diseases. Here we show that the AP-1 transcription factor JunB is required for Th17 cell development. Junb-deficient CD4+ T cells are able to develop in vitro into various helper T subsets except Th17. The RNA-seq transcriptome analysis reveals that JunB is crucial for the Th17-specific gene expression program. Junb-deficient mice are completely resistant to experimental autoimmune encephalomyelitis, a Th17-mediated inflammatory disease, and naive T helper cells from such mice fail to differentiate into Th17 cells. JunB appears to activate Th17 signature genes by forming a heterodimer with BATF, another AP-1 factor essential for Th17 differentiation. The mechanism whereby JunB controls Th17 cell development likely involves activation of the genes for the Th17 lineage-specifying orphan receptors RORγt and RORα and reduced expression of Foxp3, a transcription factor known to antagonize RORγt function.

Bidirectional factors impact the migration of NK cells to draining lymph node in aged mice during influenza virus infection.

Natural killer (NK) cells play an important role in controlling several viral diseases. Our previous studies demonstrated an age-dependent susceptibility to mousepox due to defective NK cell responses and trafficking. However, the mechanisms that underlie the age-related impairment in NK cell migration have yet to be identified. In the present study, we demonstrated that after influenza A virus (IAV) infection, NK cells from aged mice (17-19months old) failed to accumulate in draining lymph node (D-LN). We found that both environmental and intrinsic factors played roles for this defect. After infection, increase of chemokine transcripts, especially CXCL9, 10 and 11, which are important for NK cells homing to D-LN, was significantly lower in the D-LN of aged mice compared with those of young mice. Further, the expression levels of ß2-integrins and ß-actins, which play critical roles in NK cells homing to D-LN failed to be up-regulated in NK cells from aged mice. Finally, actin polymerization rates in NK cells from aged mice were also delayed compared to that of the young mice after IAV infection. Taken together, our data indicate that bi-directional factors play essential roles in the defective NK cell trafficking to the D-LN in the aged mice after IAV infection.

Intronic regulation of Aire expression by Jmjd6 for self-tolerance induction in the thymus.

The thymus has spatially distinct microenvironments, the cortex and the medulla, where the developing T-cells are selected to mature or die through the interaction with thymic stromal cells. To establish the immunological self in the thymus, medullary thymic epithelial cells (mTECs) express diverse sets of tissue-specific self-antigens (TSAs). This ectopic expression of TSAs largely depends on the transcriptional regulator Aire, yet the mechanism controlling Aire expression itself remains unknown. Here, we show that Jmjd6, a dioxygenase that catalyses lysyl hydroxylation of splicing regulatory proteins, is critical for Aire expression. Although Jmjd6 deficiency does not affect abundance of Aire transcript, the intron 2 of Aire gene is not effectively spliced out in the absence of Jmjd6, resulting in marked reduction of mature Aire protein in mTECs and spontaneous development of multi-organ autoimmunity in mice. These results highlight the importance of intronic regulation in controlling Aire protein expression.

NK-cells are involved in thymic atrophy induced by influenza A virus infection.

NK-cells have traditionally been viewed as innate effector lymphocytes that serve as a first line of defence against a range of viruses and tumours. More recently, the importance of NK-cell immunoregulatory functions has been highlighted. NK-cells can inhibit antiviral T-cell responses, and also play an important role in controlling harmful T-cell activity in autoimmunity and transplantation settings. Moreover, immunopathological effects of NK-cells during infection have been reported. Nevertheless, the phenotype and function of NK-cells in the thymus during influenza virus infection is not understood. In the present study, we demonstrated that influenza A virus (IAV) infection in mice led to severe thymic atrophy caused by increased thymic T-cell apoptosis and suppressed proliferation. We found that NK-cells played a critical role in this phenotype. IFN-c production by NK-cells was a contributing factor for thymic atrophy during IAV infection. Taken together, our data indicate that NK-cells are involved in the thymic atrophy associated with IAV infection.

DOCK5 functions as a key signaling adaptor that links FcεRI signals to microtubule dynamics during mast cell degranulation.

Mast cells play a key role in the induction of anaphylaxis, a life-threatening IgE-dependent allergic reaction, by secreting chemical mediators that are stored in secretory granules. Degranulation of mast cells is triggered by aggregation of the high-affinity IgE receptor, FcεRI, and involves dynamic rearrangement of microtubules. Although much is known about proximal signals downstream of FcεRI, the distal signaling events controlling microtubule dynamics remain elusive. Here we report that DOCK5, an atypical guanine nucleotide exchange factor (GEF) for Rac, is essential for mast cell degranulation. As such, we found that DOCK5-deficient mice exhibit resistance to systemic and cutaneous anaphylaxis. The Rac GEF activity of DOCK5 is surprisingly not required for mast cell degranulation. Instead, DOCK5 associated with Nck2 and Akt to regulate microtubule dynamics through phosphorylation and inactivation of GSK3ß. When DOCK5-Nck2-Akt interactions were disrupted, microtubule formation and degranulation response were severely impaired. Our results thus identify DOCK5 as a key signaling adaptor that orchestrates remodeling of the microtubule network essential for mast cell degranulation.