TLR4 inhibitors through inhibiting (MYD88-TRIF) pathway, protect against experimentally-induced intestinal (I/R) injury.

Intestinal ischemia/reperfusion (I/R) injury is a serious condition that causes intestinal dysfunction and can be fatal. Previous research has shown that toll-like receptor 4 (TLR4) inhibitors have a protective effect against this injury. This study aimed to investigate the protective effects of TLR4 inhibitors, specifically cyclobenzaprine, ketotifen, amitriptyline, and naltrexone, in rats with intestinal (I/R) injury. Albino rats were divided into seven groups: vehicle control, sham-operated, I/R injury, I/R-cyclobenzaprine (10 mg/kg body weight), I/R-ketotifen (1 mg/kg body weight), I/R-amitriptyline (10 mg/kg body weight), and I/R-naltrexone (4 mg/kg body weight) groups. Anesthetized rats (urethane 1.8 g/kg) underwent 30 min of intestinal ischemia by occluding the superior mesenteric artery (SMA), followed by 2 h of reperfusion. Intestinal tissue samples were collected to measure various parameters, including malondialdehyde (MDA), nitric oxide synthase (NO), myeloperoxidase (MPO), superoxide dismutase (SOD), TLR4, intercellular adhesion molecule-1 (ICAM-1), nuclear factor kappa bp65 (NF-ĸBP65), monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-α (TNF-α), macrophages CD68, myeloid differentiation factor 88 (MYD88), and toll interleukin receptor-domain-containing adaptor-inducing interferon ß (TRIF). The use of TLR4 inhibitors significantly reduced MDA, MPO, and NO levels, while increasing SOD activity. Furthermore, it significantly decreased TLR4, ICAM-1, TNF-α, MCP-1, MYD88, and TRIF levels. These drugs also showed partial restoration of normal cellular structure with reduced inflammation. Additionally, there was a decrease in NF-ĸBP65 and macrophages CD68 staining compared to rats in the I/R groups. This study focuses on how TLR4 inhibitors enhance intestinal function and protect against intestinal (I/R) injury by influencing macrophages CD86 through (MYD88-TRIF) pathway, as well as their effects on oxidation and inflammation.

TLR3 signaling-induced interferon-stimulated gene 56 plays a role in the pathogenesis of rheumatoid arthritis.

Rheumatoid fibroblast-like synoviocytes (RFLS) have an important role in the inflammatory pathogenesis of rheumatoid arthritis (RA). Toll-like receptor 3 (TLR3) is upregulated in RFLS; its activation leads to the production of interferon-ß (IFN-ß), a type I IFN. IFN-stimulated gene 56 (ISG56) is induced by IFN and is involved in innate immune responses; however, its role in RA remains unknown. Therefore, the purpose of this study was to investigate the role of TLR3-induced ISG56 in human RFLS. RFLS were treated with polyinosinic-polycytidylic acid (poly I:C), which served as a TLR3 ligand. ISG56, melanoma differentiation-associated gene 5 (MDA5), and C-X-C motif chemokine ligand 10 (CXCL10) expression were measured using quantitative reverse transcription-polymerase chain reaction, western blotting, and enzyme-linked immunosorbent assay. Using immunohistochemistry, we found that ISG56 was expressed in synovial tissues of patients with RA and osteoarthritis. Under poly I:C treatment, ISG56 was upregulated in RFLS. In addition, we found that the type I IFN-neutralizing antibody mixture suppressed ISG56 expression. ISG56 knockdown decreased CXCL10 expression and MDA5 knockdown decreased ISG56 expression. In addition, we found that ISG56 was strongly expressed in the synovial cells of patients with RA. TLR3 signaling induced ISG56 expression in RFLS and type I IFN was involved in ISG56 expression. ISG56 was also found to be associated with CXCL10 expression, suggesting that ISG56 may be involved in TLR3/type I IFN/CXCL10 axis, and play a role in RA synovial inflammation.

PM2.5 regulates the progression of lung adenocarcinoma through the axis of HCG18, miR-195 and ATG14.

Relevant studies have indicated the association of HCG18 with tumour occurrence and progression. In this study, we observed that PM2.5 can enhance the growth of lung adenocarcinoma cells by modulating the expression of HCG18. Further investigations, including overexpression and knockout experiments, elucidated that HCG18 suppresses miR-195, which in turn upregulates the expression of ATG14, resulting in the upregulation of autophagy. Consequently, exposure to PM2.5 leads to elevated HCG18 expression in lung tissues, which in turn increases Atg14 expression and activates autophagy pathways through inhibition of miR-195, thereby contributing to oncogenesis.

Hypermethylation of the Gene Body in SRCIN1 Is Involved in Breast Cancer Cell Proliferation and Is a Potential Blood-Based Biomarker for Early Detection and a Poor Prognosis.

Breast cancer is a leading cause of cancer mortality in women worldwide. Using the Infinium MethylationEPIC BeadChip, we analyzed plasma sample methylation to identify the SRCIN1 gene in breast cancer patients. We assessed SRCIN1-related roles and pathways for their biomarker potential. To verify the methylation status, quantitative methylation-specific PCR (qMSP) was performed on genomic DNA and circulating cell-free DNA samples, and mRNA expression analysis was performed using RT‒qPCR. The results were validated in a Western population; for this analysis, the samples included plasma samples from breast cancer patients from the USA and from The Cancer Genome Atlas (TCGA) cohort. To study the SRCIN1 pathway, we conducted cell viability assays, gene manipulation and RNA sequencing. SRCIN1 hypermethylation was identified in 61.8% of breast cancer tissues from Taiwanese patients, exhibiting specificity to this malignancy. Furthermore, its presence correlated significantly with unfavorable 5-year overall survival outcomes. The levels of methylated SRCIN1 in the blood of patients from Taiwan and the USA correlated with the stage of breast cancer. The proportion of patients with high methylation levels increased from 0% in healthy individuals to 63.6% in Stage 0, 80% in Stage I and 82.6% in Stage II, with a sensitivity of 78.5%, an accuracy of 90.3% and a specificity of 100%. SRCIN1 hypermethylation was significantly correlated with increased SRCIN1 mRNA expression (p < 0.001). Knockdown of SRCIN1 decreased the viability of breast cancer cells. SRCIN1 silencing resulted in the downregulation of ESR1, BCL2 and various cyclin protein expressions. SRCIN1 hypermethylation in the blood may serve as a noninvasive biomarker, facilitating early detection and prognosis evaluation, and SRCIN1-targeted therapies could be used in combination regimens for breast cancer patients.

Elevated sortilin expression discriminates functional from non-functional neuroendocrine tumors and enables therapeutic targeting.

A subset of neuroendocrine tumors (NETs) can cause an excessive secretion of hormones, neuropeptides, and biogenic amines into the bloodstream. These so-called functional NETs evoke a hormone-related disease and lead to several different syndromes, depending on the factors released. One of the most common functional syndromes, carcinoid syndrome, is characterized mainly by over-secretion of serotonin. However, what distinguishes functional from non-functional tumors on a molecular level remains unknown. Here, we demonstrate that the expression of sortilin, a widely expressed transmembrane receptor involved in intracellular protein sorting, is significantly increased in functional compared to non-functional NETs and thus can be used as a biomarker for functional NETs. Furthermore, using a cell line model of functional NETs, as well as organoids, we demonstrate that inhibition of sortilin reduces cellular serotonin concentrations and may therefore serve as a novel therapeutic target to treat patients with carcinoid syndrome.

Sortilin-Mediated Inhibition of TREK1/2 Channels in Primary Sensory Neurons Promotes Prediabetic Neuropathic Pain.

Neuropathic pain can occur during the prediabetic stage, even in the absence of hyperglycemia. The presence of prediabetic neuropathic pain (PDNP) poses challenges to the management of individuals with prediabetes. However, the mechanisms underlying this pain remain unclear. This study aims to investigate the underlying mechanism and identify potential therapeutic targets of PDNP. A prediabetic animal model induced by a high-energy diet exhibits both mechanical allodynia and thermal hyperalgesia. Furthermore, hyperexcitability and decreased potassium currents are observed in the dorsal root ganglion (DRG) neurons of these rats. TREK1 and TREK2 channels, which belong to the two-pore-domain K+ channel (K2P) family and play an important role in controlling cellular excitability, are downregulated in DRG neurons. Moreover, this alteration is modulated by Sortilin, a molecular partner that modulates the expression of TREK1. The overexpression of Sortilin negatively affects the expression of TREK1 and TREK2, leading to increased neuronal excitability in the DRG and enhanced peripheral pain sensitivity in rats. Moreover, the downregulation of Sortilin or activation of TREK1 and TREK2 channels by genetic or pharmacological approaches can alleviate PDNP. Therefore, targeting the Sortilin-mediated TREK1/2 pathway may provide a therapeutic approach for ameliorating PDNP.

Iron Oxide Nanoparticles Inhibit Tumor Progression and Suppress Lung Metastases in Mouse Models of Breast Cancer.

Systemic exposure to starch-coated iron oxide nanoparticles (IONPs) can stimulate antitumor T cell responses, even when little IONP is retained within the tumor. Here, we demonstrate in mouse models of metastatic breast cancer that IONPs can alter the host immune landscape, leading to systemic immune-mediated disease suppression. We report that a single intravenous injection of IONPs can inhibit primary tumor growth, suppress metastases, and extend survival. Gene expression analysis revealed the activation of Toll-like receptor (TLR) pathways involving signaling via Toll/Interleukin-1 receptor domain-containing adaptor-inducing IFN-ß (TRIF), a TLR pathway adaptor protein. Requisite participation of TRIF in suppressing tumor progression was demonstrated with histopathologic evidence of upregulated IFN-regulatory factor 3 (IRF3), a downstream protein, and confirmed in a TRIF knockout syngeneic mouse model of metastatic breast cancer. Neither starch-coated polystyrene nanoparticles lacking iron, nor iron-containing dextran-coated parenteral iron replacement agent, induced significant antitumor effects, suggesting a dependence on the type of IONP formulation. Analysis of multiple independent clinical databases supports a hypothesis that upregulation of TLR3 and IRF3 correlates with increased overall survival among breast cancer patients. Taken together, these data support a compelling rationale to re-examine IONP formulations as harboring anticancer immune (nano)adjuvant properties to generate a therapeutic benefit without requiring uptake by cancer cells.

Flotillins affect LPS-induced TLR4 signaling by modulating the trafficking and abundance of CD14.

Lipopolysaccharide (LPS) induces a strong pro-inflammatory reaction of macrophages upon activation of Toll-like receptor 4 (TLR4) with the assistance of CD14 protein. Considering a key role of plasma membrane rafts in CD14 and TLR4 activity and the significant impact exerted on that activity by endocytosis and intracellular trafficking of the both LPS acceptors, it seemed likely that the pro-inflammatory reaction could be modulated by flotillins. Flotillin-1 and -2 are scaffolding proteins associated with the plasma membrane and also with endo-membranes, affecting both the plasma membrane dynamics and intracellular protein trafficking. To verify the above hypothesis, a set of shRNA was used to down-regulate flotillin-2 in Raw264 cells, which were found to also become deficient in flotillin-1. The flotillin deficiency inhibited strongly the TRIF-dependent endosomal signaling of LPS-activated TLR4, and to a lower extent also the MyD88-dependent one, without affecting the cellular level of TLR4. The flotillin depletion also inhibited the pro-inflammatory activity of TLR2/TLR1 and TLR2/TLR6 but not TLR3. In agreement with those effects, the depletion of flotillins down-regulated the CD14 mRNA level and the cellular content of CD14 protein, and also inhibited constitutive CD14 endocytosis thereby facilitating its shedding. Ultimately, the cell-surface level of CD14 was markedly diminished. Concomitantly, CD14 recycling was enhanced via EEA1-positive early endosomes and golgin-97-positive trans-Golgi network, likely to compensate for the depletion of the cell-surface CD14. We propose that the paucity of surface CD14 is the reason for the down-regulated signaling of TLR4 and the other TLRs depending on CD14 for ligand binding.

Toll-like receptor signaling pathway involved in pathogenesis of thromboangiitis obliterans through activating of NF-κB.

OBJECTIVES: The pathogenic mechanisms of Thromboangiitis Obliterans (TAO) are not entirely known and autoimmune inflammation plays a vital role in the initiation and continuance of TAO activity. The authors investigated in this study the role of the TLR signaling pathway in the pathogenesis of TAO. METHODS: First, the authors detected the expressions of MyD88, TRIF and NF-κB in vascular walls of 46 patients with TAO and 32 patients with trauma and osteosarcoma by western blot assay. Second, the authors detected the cellular localization of MyD88, TRIF and NF-κB in vascular walls of patients with TAO by immunofluorescent assay. RESULTS: The protein expressions of MyD88, TRIF and NF-κB were much higher in vascular walls of TAO patients (p < 0.05). Higher expressions of MyD88 and NF-κB were detected both on vascular endothelial and vascular smooth muscle cells of TAO patients. However, higher expression of TRIF was just detected on vascular smooth muscle cells of TAO patients. CONCLUSIONS: These dates suggest that the TLR signaling pathway might play an important role in the pathogenesis of TAO, it might induce vasospasm, vasculitis and thrombogenesis to lead to the pathogenesis and progression of TAO.

The role of the AP-1 adaptor complex in outgoing and incoming membrane traffic.

The AP-1 adaptor complex is found in all eukaryotes, but it has been implicated in different pathways in different organisms. To look directly at AP-1 function, we generated stably transduced HeLa cells coexpressing tagged AP-1 and various tagged membrane proteins. Live cell imaging showed that AP-1 is recruited onto tubular carriers trafficking from the Golgi apparatus to the plasma membrane, as well as onto transferrin-containing early/recycling endosomes. Analysis of single AP-1 vesicles showed that they are a heterogeneous population, which starts to sequester cargo 30 min after exit from the ER. Vesicle capture showed that AP-1 vesicles contain transmembrane proteins found at the TGN and early/recycling endosomes, as well as lysosomal hydrolases, but very little of the anterograde adaptor GGA2. Together, our results support a model in which AP-1 retrieves proteins from post-Golgi compartments back to the TGN, analogous to COPI's role in the early secretory pathway. We propose that this is the function of AP-1 in all eukaryotes.

Key roles for phosphorylation and the Coiled-coil domain in TRIM56-mediated positive regulation of TLR3-TRIF-dependent innate immunity.

Tripartite-motif protein-56 (TRIM56) positively regulates the induction of type I interferon response via the TLR3 pathway by enhancing IRF3 activation and depends on its C-terminal residues 621-750 for interacting with the adaptor TRIF. However, the precise underlying mechanism and detailed TRIM56 determinants remain unclear. Herein, we show ectopic expression of murine TRIM56 also enhances TLR3-dependent interferon-ß promoter activation, suggesting functional conservation. We found that endogenous TRIM56 and TRIF formed a complex early (0.5-2 h) after poly-I:C stimulation and that TRIM56 overexpression also promoted activation of NF-κB by poly-I:C but not that by TNF-α or IL-1ß, consistent with a specific effect on TRIF prior to the bifurcation of NF-κB and IRF3. Using transient transfection and Tet-regulated cell lines expressing various TRIM56 mutants, we demonstrated the Coiled-coil domain and a segment spanning residues ∼434-610, but not the B-box or residues 355-433, were required for TRIM56 augmentation of TLR3 signaling. Moreover, alanine substitution at each putative phosphorylation site, Ser471, Ser475, and Ser710, abrogated TRIM56 function. Concordantly, mutants bearing Ser471Ala, Ser475Ala, or Ser710Ala, or lacking the Coiled-coil domain, all lost the capacity to enhance poly-I:C-induced establishment of an antiviral state. Furthermore, the Ser710Ala mutation disrupted the TRIM56-TRIF association. Using phospho-specific antibodies, we detected biphasic phosphorylation of TRIM56 at Ser471 and Ser475 following TLR3 stimulation, with the early phase occurring at ∼0.5 to 1 h, prior to IRF3 phosphorylation. Together, these data reveal novel molecular details critical for the TRIM56 augmentation of TLR3-dependent antiviral response and highlight important roles for TRIM56 scaffolding and phosphorylation.

Sortilin in Biliary Epithelial Cells Promotes Ductular Reaction and Fibrosis during Cholestatic Injury.

Cholestatic injuries are accompanied by ductular reaction, initiated by proliferation and activation of biliary epithelial cells (BECs), leading to fibrosis. Sortilin (encoded by Sort1) facilitates IL-6 secretion and leukemia inhibitory factor (LIF) signaling. This study investigated the interplay between sortilin and IL-6 and LIF in cholestatic injury-induced ductular reaction, morphogenesis of new ducts, and fibrosis. Cholestatic injury was induced by bile duct ligation (BDL) in wild-type and Sort1-/- mice, with or without augmentation of IL-6 or LIF. Mice with BEC sortilin deficiency (hGFAPcre.Sort1fl/fl) and control mice were subjected to BDL and 3,5-diethoxycarbonyl-1,4-dihydrocollidine diet (DDC) induced cholestatic injury. Sort1-/- mice displayed reduced BEC proliferation and expression of BEC-reactive markers. Administration of LIF or IL-6 restored BEC proliferation in Sort1-/- mice, without affecting BEC-reactive or inflammatory markers. Sort1-/- mice also displayed impaired morphogenesis, which was corrected by LIF treatment. Similarly, hGFAPcre.Sort1fl/fl mice exhibited reduced BEC proliferation, but similar reactive and inflammatory marker expression. Serum IL-6 and LIF were comparable, yet liver pSTAT3 was reduced, indicating that sortilin is essential for co-activation of LIF receptor/gp130 signaling in BECs, but not for IL-6 secretion. hGFAPcre.Sortfl/fl mice displayed impaired morphogenesis and diminished fibrosis after BDL and DDC. In conclusion, sortilin-mediated engagement of LIF signaling in BECs promoted ductular reaction and morphogenesis during cholestatic injury. This study indicates that BEC sortilin is pivotal for the development of fibrosis.

ZBP1 and TRIF trigger lethal necroptosis in mice lacking caspase-8 and TNFR1.

Necroptosis is a lytic form of cell death that is mediated by the kinase RIPK3 and the pseudokinase MLKL when caspase-8 is inhibited downstream of death receptors, toll-like receptor 3 (TLR3), TLR4, and the intracellular Z-form nucleic acid sensor ZBP1. Oligomerization and activation of RIPK3 is driven by interactions with the kinase RIPK1, the TLR adaptor TRIF, or ZBP1. In this study, we use immunohistochemistry (IHC) and in situ hybridization (ISH) assays to generate a tissue atlas characterizing RIPK1, RIPK3, Mlkl, and ZBP1 expression in mouse tissues. RIPK1, RIPK3, and Mlkl were co-expressed in most immune cell populations, endothelial cells, and many barrier epithelia. ZBP1 was expressed in many immune populations, but had more variable expression in epithelia compared to RIPK1, RIPK3, and Mlkl. Intriguingly, expression of ZBP1 was elevated in Casp8-/- Tnfr1-/- embryos prior to their succumbing to aberrant necroptosis around embryonic day 15 (E15). ZBP1 contributed to this embryonic lethality because rare Casp8-/- Tnfr1-/- Zbp1-/- mice survived until after birth. Necroptosis mediated by TRIF contributed to the demise of Casp8-/- Tnfr1-/- Zbp1-/- pups in the perinatal period. Of note, Casp8-/- Tnfr1-/- Trif-/- Zbp1-/- mice exhibited autoinflammation and morbidity, typically within 5-7 weeks of being born, which is not seen in Casp8-/- Ripk1-/- Trif-/- Zbp1-/-, Casp8-/- Ripk3-/-, or Casp8-/- Mlkl-/- mice. Therefore, after birth, loss of caspase-8 probably unleashes RIPK1-dependent necroptosis driven by death receptors other than TNFR1.

High-speed measurements of SNARE-complexin interactions using magnetic tweezers.

In neuroscience, understanding the mechanics of synapses, especially the function of force-sensitive proteins at the molecular level, is essential. This need emphasizes the importance of precise measurement of synaptic protein interactions. Addressing this, we introduce high-resolution magnetic tweezers (MT) as a novel method to probe the mechanics of synapse-related proteins with high precision. We demonstrate this technique through studying SNARE-complexin interactions, crucial for synaptic transmission, showcasing its capability to apply specific forces to individual molecules. Our results reveal that high-resolution MT provides in-depth insights into the stability and dynamic transitions of synaptic protein complexes. This method is a significant advancement in synapse biology, offering a new tool for researchers to investigate the impact of mechanical forces on synaptic functions and their implications for neurological disorders.

CPLX2 is a novel tumor suppressor and improves the prognosis in glioma.

BACKGROUND: Glioma is a type of malignant cancer that affect the central nervous system. New predictive biomarkers have been investigated in recent years, but the clinical prognosis for glioma remains poor. The function of CPLX2 in glioma and the probable molecular mechanism of tumor suppression were the focus of this investigation. METHODS: The glioma transcriptome profile was downloaded from The Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA) databases for analysis of CPLX2 expression in glioma. RT-qPCR was performed to detect the expression of CPLX2 in 68 glioma subjects who have been followed up. Kaplan-Meier survival analyses were conducted to assess the effect of CPLX2 on the prognosis of glioma patients. The knockdown and overexpressed cell lines of CPLX2 were constructed to investigate the impact of CPLX2 on glioma. The cell growth, colony formation, and tumor formation in xenograft were performed. RESULTS: The expression of CPLX2 was downregulated in glioma and was negatively correlated with the grade of glioma. The higher expression of CPLX2 predicted a longer survival, as indicated by the analysis of Kaplan-Meier survival curves. Overexpressed CPLX2 impaired tumorigenesis in glioma progression both in vivo and in vitro. Knocking down CPLX2 promoted the proliferation of glioma cells. The analysis of GSEA and co-expression analysis revealed that CPLX2 may affect the malignancy of glioma by regulating the hypoxia and inflammation pathways. CONCLUSIONS: Our data indicated that CPLX2 functions as a tumor suppressor and could be used as a potential prognostic marker in glioma.

Sortilin inhibition in microglial cells cannot alleviate ischemia and hypoxia-induced neuronal injury in co-culture.

Sortilin is a single-pass type I transmembrane protein which can bind to various cargo proteins, regulating their surface location, secretion, or degradation in lysosomes. In our previous study, we found that sortilin can regulate progranulin expression by transporting it to lysosomes and reduce neuronal cell injury in hypoxia-ischemia, but the expression and function of sortilin in microglial cells during hypoxia-ischemia are unknown. The purpose of this study was to further investigate the function of sortilin in microglial cells and its effect on neuron cells. In rat BV2 microglial cells, sortilin was knocked down by lentivirus. After oxygen-glucose deprivation/reperfusion (OGD/R), expression of sortilin, progranulin (PGRN) and JNK pathway was detected by western blot, immunofluorescence was used to show the localization of PGRN, secretion of TNFα/IL-6 was measured by Elisa. Then co-culture microglial cells with neuron cells during hypoxia-ischemia and detected the neuron injury by CCK-8 and TUNEL. The expression of sortilin, mature and cleaved PGRN were all increased after OGD/R in microglial cells. Furthermore, sortilin inhibition accompany with less PGRN localization in lysosomes and more mature and less cleaved PGRN expression in microglial cells. Sortilin inhibition also can reduce the inflammatory response in microglial cells, but it does not alleviate neuronal injury in co-culture. This study demonstrated that sortilin can regulate the expression of PGRN and reduce the inflammatory response in microglial cells. However, only inhibiting sortilin in microglial cells did not have an impact on the survival of neurons during ischemia-hypoxia.

Sortilin Expression Levels and Peripheral Immunity: A Potential Biomarker for Segregation between Parkinson's Disease Patients and Healthy Controls.

Parkinson's disease (PD) is characterized by substantial phenotypic heterogeneity that limits the disease prognosis and patient's counseling, and complicates the design of further clinical trials. There is an unmet need for the development and validation of biomarkers for the prediction of the disease course. In this study, we utilized flow cytometry and in vitro approaches on peripheral blood cells and isolated peripheral blood mononuclear cell (PBMC)-derived macrophages to characterize specific innate immune populations in PD patients versus healthy donors. We found a significantly lower percentage of B lymphocytes and monocyte populations in PD patients. Monocytes in PD patients were characterized by a higher CD40 expression and on-surface expression of the type I membrane glycoprotein sortilin, which showed a trend of negative correlation with the age of the patients. These results were further investigated in vitro on PBMC-derived macrophages, which, in PD patients, showed higher sortilin expression levels compared to cells from healthy donors. The treatment of PD-derived macrophages with oxLDL led to higher foam cell formation compared to healthy donors. In conclusion, our results support the hypothesis that surface sortilin expression levels on human peripheral monocytes may potentially be utilized as a marker of Parkinson's disease and may segregate the sporadic versus the genetically induced forms of the disease.

Downregulation of transcription 1 hinders the replication of Dabie bandavirus by promoting the expression of TLR7, TLR8, and TLR9 signaling pathway.

Severe fever with thrombocytopenia syndrome virus (SFTSV) is a bunyavirus that causes SFTS, with a case fatality rate of up to 30 %. The innate immune system plays a crucial role in the defense against SFTSV; however, the impact of viral propagation of STFSV on the innate immune system remains unclear. Although proteomics analysis revealed that the expression of the downregulator of transcription 1 (DR1) increased after SFTSV infection, the specific change trend and the functional role of DR1 during viral infection remain unelucidated. In this study, we demonstrate that DR1 was highly expressed in response to SFTSV infection in HEK 293T cells using qRT-PCR and Western blot analysis. Furthermore, viral replication significantly increased the expression of various TLRs, especially TLR9. Our data indicated that DR1 positively regulated the expression of TLRs in HEK 293T cells, DR1 overexpression highly increased the expression of numerous TLRs, whereas RNAi-mediated DR1 silencing decreased TLR expression. Additionally, the myeloid differentiation primary response gene 88 (MyD88)-dependent or TIR-domain-containing adaptor inducing interferon-ß (TRIF)-dependent signaling pathways were highly up- and downregulated by the overexpression and silencing of DR1, respectively. Finally, we report that DR1 stimulates the expression of TLR7, TLR8, and TLR9, thereby upregulating the TRIF-dependent and MyD88-dependent signaling pathways during the SFTSV infection, attenuating viral replication, and enhancing the production of type I interferon and various inflammatory factors, including IL-1ß, IL-6, and IL-8. These results imply that DR1 defends against SFTSV replication by inducing the expression of TLR7, TLR8, and TLR9. Collectively, our findings revealed a novel role and mechanism of DR1 in mediating antiviral responses and innate immunity.

Toll-like receptor and C-type lectin receptor agonists attenuate osteogenic differentiation in human dental pulp stem cells.

BACKGROUND: This study aimed to investigate the effects of various toll-like receptor (TLR) and C-type lectin receptor (CLR) ligands on osteogenic differentiation in human dental pulp stem cells (hDPSCs). METHODS: hDPSCs were cultured and treated with various concentrations (0.01, 0.1, 1.0, and 10 µg/mL) of TLR or CLR agonists (PG-LPS, E.coli LPS, poly(I:C), Pam3CSK4, Furfurman, and Zymosan). Cell viability was determined by MTT assay. The effects of TLR and CLR agonists on osteogenic differentiation of hDPSCs were measured by alkaline phosphatase (ALP) activity, Alizarin Red S staining, and Von Kossa staining. In addition, the mRNA expression of osteogenesis-related genes (ALP, COL1A1, RUNX2, OSX, OCN and DMP1) was examined by RT-qPCR. A non-parametric analysis was employed for the statistical analyses. The statistically significant difference was considered when p < 0.05. RESULTS: Treatment with TLR and CLR agonists was associated with an increase in hDPSCs' colony-forming unit ability. Compared with the control group, TLR and CLR agonists significantly inhibited the osteogenic differentiation of hDPSCs by decreasing the ALP activity, mineralised nodule formation, and mRNA expression levels of osteogenesis-related genes (ALP, COL1A1, RUNX2, OSX, OCN and DMP1). The inhibition of TRIF but not Akt signalling rescued the effects of TLR and CLR agonist attenuating hDPSCs' mineralisation. CONCLUSIONS: The activation of TLRs or CLRs exhibited an inhibitory effect on osteogenic differentiation of hDPSCs via the TRIF-dependent signalling pathway.

Lysosomal membrane proteins LAMP1 and LIMP2 are segregated in the Golgi apparatus independently of their clathrin adaptor binding motif.

To reach the lysosome, lysosomal membrane proteins (LMPs) are translocated in the endoplasmic reticulum after synthesis and then transported to the Golgi apparatus. The existence of a direct transport from the Golgi apparatus to the endosomes but also of an indirect route through the plasma membrane has been described. Clathrin adaptor binding motifs contained in the cytosolic tail of LMPs have been described as key players in their intracellular trafficking. Here we used the RUSH assay to synchronize the biosynthetic transport of multiple LMPs. After exiting the Golgi apparatus, RUSH-synchronized LAMP1 was addressed to the cell surface both after overexpression or at endogenous level. Its YXXΦ motif was not involved in the transport from the Golgi apparatus to the plasma membrane but in its endocytosis. LAMP1 and LIMP2 were sorted from each other after reaching the Golgi apparatus. LIMP2 was incorporated in punctate structures for export from the Golgi apparatus from which LAMP1 is excluded. LIMP2-containing post-Golgi transport intermediates did not rely neither on its adaptor binding signal nor on its C-terminal cytoplasmic domain.