Dynamic Hybrid Module-Driven NK Cell Stimulation and Release for Tumor Immunotherapy.

Natural killer (NK) cells have become a powerful candidate for adoptive tumor immunotherapy, while their therapeutic efficacy in solid tumors remains unsatisfactory. Here, we developed a hybrid module with an injectable hydrogel and hydroxyapatite (HAp) nanobelts for the controlled delivery of NK cells to enhance the therapy of solid tumors. Surface-functionalized HAp nanobelts modified with agonistic antibodies against NKG2D and 4-1BB and cytokines IL-2 and IL-21 support survival and dynamic activation. Thus, the HAp-modified chitosan (CS) thermos-sensitive hydrogel not only improved the retention of NK cells for more than 20 days in vivo but also increased NK cell function by more than one-fold. The unique architecture of this biomaterial complex protects NK cells from the hostile tumor environment and improves antitumor efficacy. The generation of a transient inflammatory niche for NK cells through a biocompatible hydrogel reservoir may be a conversion pathway to prevent cancer recurrence of resectable tumors.

Evaluation of aphid resistance on different rose cultivars and transcriptome analysis in response to aphid infestation.

BACKGROUND: The rose is one of the most important ornamental flowers in the world for its aesthetic beauty but can be attacked by many pests such as aphids. Aphid infestation causes tremendous damage on plant tissues leading to harmed petals and leaves. Rose cultivars express different levels of resistance to aphid infestation yet the information remains unclear. Not only that, studies about the transcriptional analysis on defending mechanisms against aphids in rose are limited so far. RESULTS: In this study, the aphid resistance of 20 rose cultivars was evaluated, and they could be sorted into six levels based on the number ratio of aphids. And then, a transcriptome analysis was conducted after aphid infestation in one high resistance (R, Harmonie) and one highly susceptibility (S, Carefree Wonder) rose cultivar. In open environment the majority of rose cultivars had the highest aphid number at May 6th or May 15th in 2020 and the resistance to infestation could be classified into six levels. Differential expression analysis revealed that there were 1,626 upregulated and 767 downregulated genes in the R cultivar and 481 upregulated and 63 downregulated genes in the S cultivar after aphid infestation. Pathway enrichment analysis of the differentially expressed genes revealed that upregulated genes in R and S cultivars were both enriched in defense response, biosynthesis of secondary metabolites (phenylpropanoid, alkaloid, and flavonoid), carbohydrate metabolism (galactose, starch, and sucrose metabolism) and lipid processing (alpha-linolenic acid and linolenic acid metabolism) pathways. In the jasmonic acid metabolic pathway, linoleate 13S-lipoxygenase was specifically upregulated in the R cultivar, while genes encoding other crucial enzymes, allene oxide synthase, allene oxide cyclase, and 12-oxophytodienoate reductase were upregulated in both cultivars. Transcription factor analysis and transcription factor binding search showed that WRKY transcription factors play a pivotal role during aphid infestation in the R cultivar. CONCLUSIONS: Our study indicated the potential roles of jasmonic acid metabolism and WRKY transcription factors during aphid resistance in rose, providing clues for future research.

Increased Siglec-9/Siglec-9L interactions on NK cells predict poor HCC prognosis and present a targetable checkpoint for immunotherapy.

BACKGROUND & AIMS: Natural killer (NK) cell-based anti-hepatocellular carcinoma (HCC) therapy is an increasingly attractive approach that warrants further study. Siglec-9 interacts with its ligand (Siglec-9L) and restrains NK cell functions, suggesting it is a potential therapeutic target. However, in situ Siglec-9/Siglec-9L interactions in HCC have not been reported, and a relevant interventional strategy is lacking. Herein, we aim to illustrate Siglec-9/Siglec-9L-mediated cell sociology and identify small-molecule inhibitors targeting Siglec-9 that could improve the efficacy of NK cell-based immunotherapy for HCC. METHODS: Multiplexed immunofluorescence staining was performed to analyze the expression pattern of Siglec-7, -9 and their ligands in HCC tissues. Then we conducted docking-based virtual screening combined with bio-layer interferometry assays to identify a potent small-molecule Siglec-9 inhibitor. The therapeutic potential was further evaluated in vitro and in hepatoma-bearing NCG mice. RESULTS: Siglec-9 expression, rather than Siglec-7, was markedly upregulated on tumor-infiltrating NK cells, which correlated significantly with reduced survival of patients with HCC. Moreover, the number of Siglec-9L+ cells neighboring Siglec-9+ NK cells was increased in HCC tissues and was also associated with tumor recurrence and reduced survival, further suggesting that Siglec-9/Siglec-9L interactions are a potential therapeutic target in HCC. In addition, we identified a small-molecule Siglec-9 inhibitor MTX-3937 which inhibited phosphorylation of Siglec-9 and downstream SHP1 and SHP2. Accordingly, MTX-3937 led to considerable improvement in NK cell function. Notably, MTX-3937 enhanced cytotoxicity of both human peripheral and tumor-infiltrating NK cells. Furthermore, transfer of MTX-3937-treated NK92 cells greatly suppressed the growth of hepatoma xenografts in NCG mice. CONCLUSIONS: Our study provides the rationale for HCC treatment by targeting Siglec-9 on NK cells and identifies a promising small-molecule inhibitor against Siglec-9 that enhances NK cell-mediated HCC surveillance. IMPACT AND IMPLICATIONS: Herein, we found that Siglec-9 expression is markedly upregulated on tumor-infiltrating natural killer (TINK) cells and correlates with reduced survival in patients with hepatocellular carcinoma (HCC). Moreover, the number of Siglec-9L+ cells neighboring Siglec-9+ NK cells was increased in HCC tissues and was also associated with tumor recurrence and reduced survival. More importantly, we identified a small-molecule inhibitor targeting Siglec-9 that augments NK cell functions, revealing a novel immunotherapy strategy for liver cancer that warrants further clinical investigation.

Tim-4 alleviates acute hepatic injury by modulating homeostasis and function of NKT cells.

T-cell immunoglobulin and mucin domain-containing molecule 4 (Tim-4) is an immune checkpoint molecule, which involves in numerous inflammatory diseases. Tim-4 is mainly expressed on antigen-presenting cells. However, increasing evidence has shown that Tim-4 is also expressed on natural killer T (NKT) cells. The role of Tim-4 in maintaining NKT cell homeostasis and function remains unknown. In this study, we explored the effect of Tim-4 on NKT cells in acute liver injury. This study found that Tim-4 expression on hepatic NKT cells was elevated during acute liver injury. Tim-4 deficiency enhanced IFN-γ, TNF-α expression while impaired IL-4 production in NKT cells. Loss of Tim-4 drove NKT-cell effector lineages to be skewed to NKT1 subset. Furthermore, Tim-4 KO mice were more susceptible to α-Galactosylceramide (α-GalCer) challenge. In conclusion, our findings indicate that Tim-4 plays an important role in regulating homeostasis and function of NKT cells in acute liver injury. Therefore, Tim-4 might become a new regulator of NKT cells and a potential target for the therapy of acute hepatitis.

VEGFR2 blockade inhibits glioblastoma cell proliferation by enhancing mitochondrial biogenesis.

BACKGROUND: Glioblastoma is an aggressive brain tumor linked to significant angiogenesis and poor prognosis. Anti-angiogenic therapies with vascular endothelial growth factor receptor 2 (VEGFR2) inhibition have been investigated as an alternative glioblastoma treatment. However, little is known about the effect of VEGFR2 blockade on glioblastoma cells per se. METHODS: VEGFR2 expression data in glioma patients were retrieved from the public database TCGA. VEGFR2 intervention was implemented by using its selective inhibitor Ki8751 or shRNA. Mitochondrial biogenesis of glioblastoma cells was assessed by immunofluorescence imaging, mass spectrometry, and western blot analysis. RESULTS: VEGFR2 expression was higher in glioma patients with higher malignancy (grade III and IV). VEGFR2 inhibition hampered glioblastoma cell proliferation and induced cell apoptosis. Mass spectrometry and immunofluorescence imaging showed that the anti-glioblastoma effects of VEGFR2 blockade involved mitochondrial biogenesis, as evidenced by the increases of mitochondrial protein expression, mitochondria mass, mitochondrial oxidative phosphorylation (OXPHOS), and reactive oxygen species (ROS) production, all of which play important roles in tumor cell apoptosis, growth inhibition, cell cycle arrest and cell senescence. Furthermore, VEGFR2 inhibition exaggerated mitochondrial biogenesis by decreased phosphorylation of AKT and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α), which mobilized PGC1α into the nucleus, increased mitochondrial transcription factor A (TFAM) expression, and subsequently enhanced mitochondrial biogenesis. CONCLUSIONS: VEGFR2 blockade inhibits glioblastoma progression via AKT-PGC1α-TFAM-mitochondria biogenesis signaling cascade, suggesting that VEGFR2 intervention might bring additive therapeutic values to anti-glioblastoma therapy.

NAD + salvage governs mitochondrial metabolism, invigorating natural killer cell antitumor immunity.

BACKGROUND AND AIMS: Natural killer (NK) cells are key players in tumor immunosurveillance, and metabolic adaptation manipulates their fate and functional state. The nicotinamide adenine dinucleotide (NAD + ) has emerged as a vital factor to link cellular metabolism and signaling transduction. Here, we identified NAD + metabolism as a central hub to determine the homeostasis and function of NK cells. APPROACH AND RESULTS: NAD + level was elevated in activated NK cells. NAD + supplementation not only enhanced cytokine production and cytotoxicity but also improved the proliferation and viability of NK cells. Intriguingly, the salvage pathway was involved in maintaining NAD + homeostasis in activated NK cells. Genetic ablation or pharmacological blockade of nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme in the NAD + salvage pathway, markedly destroyed the viability and function of NK cells. Mechanistically, NAD + salvage dictated the mitochondrial homeostasis and oxidative phosphorylation activity to support the optimal function of NK cells. However, in human HCC tissues, NAMPT expression and NAD + level were significantly down-regulated in tumor-infiltrating NK cells, which negatively correlated with patient survival. And lactate accumulation in the tumor microenvironment was at least partially responsible for the transcriptional repression of NAMPT in NK cells. Further, deficiency of Nampt in NK cells accelerated the growth of HCC and melanoma. Supplementation of the NAD + precursor nicotinamide mononucleotide (NMN) significantly improved NK antitumor response in both mouse and human cell-derived xenografts. CONCLUSIONS: These findings reveal NAD + salvage as an essential factor for NK-cell homeostasis and function, suggesting a potential strategy for invigorating NK cell-based immunotherapy.

T-cell immunoglobulin- and mucin-domain-containing molecule-4 maintains adipose tissue homeostasis by orchestrating M2 macrophage polarization via nuclear factor kappa B pathway.

Obesity is generally associated with low-grade inflammation. Adipose tissue macrophages (ATMs) orchestrate metabolic inflammation. The classical (M1-like) or alternative (M2-like) activation of ATMs is functionally coupled with the metabolic status of fat tissues. It has been found that T-cell immunoglobulin- and mucin-domain-containing molecule-4 (Tim-4) inhibits inflammation by regulating macrophages. However, the exact role of Tim-4 in macrophage polarization and obesity remains unknown. Here, we identified Tim-4 as a critical switch governing macrophage M1/M2 polarization and energy homeostasis. Tim-4 deletion led to spontaneous obesity in elder mice and promoted obesity severity of db/db mice. Obesity microenvironment enhanced the expression of Tim-4 in white adipose tissue and ATMs. In vitro, we detected an increase in M1-like cells and decrease in M2-like cells in both peritoneal macrophages and bone marrow-derived macrophages from Tim-4 knockout mice. Mechanistically, we demonstrated that Tim-4 promoted M2-like macrophages polarization via suppressing nuclear factor kappa B (NF-κB) signaling pathway. In addition, we found that Tim-4 promoted TLR4 internalization, which might contribute to regulation of NF-κB signaling. Collectively, these results indicated that Tim-4 maintained adipose tissue homeostasis by regulating macrophage polarization via NF-κB pathway, which would provide a new target for obesity intervention.

SREBF2-STARD4 axis confers sorafenib resistance in hepatocellular carcinoma by regulating mitochondrial cholesterol homeostasis.

Sorafenib resistance limits its survival benefit for treatment of hepatocellular carcinoma (HCC). Cholesterol metabolism is dysregulated in HCC, and its role in sorafenib resistance of HCC has not been fully elucidated. Aiming to elucidate this, in vitro and in vivo sorafenib resistant models were established. Sterol regulatory element binding transcription factor 2 (SREBF2), the key regulator of cholesterol metabolism, was activated in sorafenib resistant HepG2 and Huh7 cells. Knockdown of SREBF2 resensitized sorafenib resistant cells and xenografts tumors to sorafenib. Further study showed that SREBF2 positively correlated with StAR related lipid transfer domain containing 4 (STARD4) in our sorafenib resistant models and publicly available datasets. STARD4, mediating cholesterol trafficking, not only promoted proliferation and migration of HepG2 and Huh7 cells, but also increased sorafenib resistance in liver cancer. Mechanically, SREBF2 promoted expression of STARD4 by directly binding to its promoter region, leading to increased mitochondrial cholesterol levels and inhibition of mitochondrial cytochrome c release. Importantly, knockdown of SREBF2 or STARD4 decreased mitochondrial cholesterol levels and increased mitochondrial cytochrome c release, respectively. Moreover, overexpression of STARD4 reversed the effect of SREBF2 knockdown on mitochondrial cytochrome c release and sorafenib resistance. In conclusion, SREBF2 promotes STARD4 transcription, which in turn contributes to mitochondrial cholesterol transport and sorafenib resistance in HCC. Therefore, targeting the SREBF2-STARD4 axis would be beneficial to a subset of HCC patients with sorafenib resistance.

Research progress on pathogenic and therapeutic mechanisms of Enterovirus A71.

In recent years, enterovirus A71 (EV-A71) infection has become a major global public health problem, especially for infants and young children. The results of epidemiological research show that EV-A71 infection can cause acute hand, foot, and mouth disease (HFMD) and complications of the nervous system in severe cases, including aseptic pediatric meningoencephalitis, acute flaccid paralysis, and even death. Many studies have demonstrated that EV-A71 infection may trigger a variety of intercellular and intracellular signaling pathways, which are interconnected to form a network that leads to the innate immune response, immune escape, inflammation, and apoptosis in the host. This article aims to provide an overview of the possible mechanisms underlying infection, signaling pathway activation, the immune response, immune evasion, apoptosis, and the inflammatory response caused by EV-A71 infection and an overview of potential therapeutic strategies against EV-A71 infection to better understand the pathogenesis of EV-A71 and to aid in the development of antiviral drugs and vaccines.

Spatial distribution and functional analysis define the action pathway of Tim-3/Tim-3 ligands in tumor development.

The spatial organization of immune cells within the tumor microenvironment (TME) largely determines the anti-tumor immunity and also highly predicts tumor progression and therapeutic response. Tim-3 is a well-accepted immune checkpoint and plays multifaceted immunoregulatory roles via interaction with distinct Tim-3 ligands (Tim-3L), showing great potential as an immunotherapy target. However, the cell sociology mediated by Tim-3/Tim-3L and their contribution to tumor development remains elusive. Here, we analyzed the spatial distribution of Tim-3/Tim-3L in TME using multiplex fluorescence staining and revealed that despite the increased Tim-3 expression in various tumor-infiltrated lymphocytes, Tim-3+CD4+ cells were more accumulated in parenchymal/tumor region compared with stromal region and exhibited more close association with patient survival. Strikingly, CD4 T cells surrounding Tim-3L+ cells expressed higher Tim-3 than other cells in cancerous tissues. In vivo studies confirmed that depletion of CD4 T cells completely abrogated the inhibition of tumor growth and metastasis, as well as the functional improvement of CD8 T and NK, mediated by Tim-3 blockade, which was further validated in peripheral lymphocytes from patients with hepatocellular carcinoma. In conclusion, our findings unravel the importance of CD4 T cells in Tim-3/Tim-3L-mediated immunosuppression and provide new thoughts for Tim-3 targeted cancer immunotherapy.

Platelets fine-tune effector responses of naïve CD4+ T cells via platelet factor 4-regulated transforming growth factor ß signaling.

BACKGROUND AND AIM: Platelets are an able regulator of CD4+ T cell immunity. Herein, the mechanisms underlying platelet-regulated effector responses of naïve CD4+ T (Tn) cells were investigated. METHODS: Platelet-Tn cell co-cultures of human cells, genetically modified murine models, and high-throughput bioinformatic analyses were combined to elucidate molecular mechanisms of platelet-dependent regulation. RESULTS: Platelets exerted sophisticated regulation on effector responses of type 1, 2, and 17 T helper (Th1/Th2/Th17) and regulatory T (Treg) cells, in time-, concentration-, and organ-dependent manners and with close cooperation of transforming growth factor ß (TGFß) and platelet factor 4 (PF4). PF4 at low concentrations reinforced TGFß signaling by heteromerizing with type III TGFß receptor (TGFBRIII), and subsequently enhanced TGFBRII expression and TGFß signaling. High-concentration PF4 had, however, opposite effects by directly binding to TGFBRII, blocking TGFß-TGFBRII ligation, and thus inhibiting TGFß signaling. Furthermore, platelet depletion markedly hampered Treg and Th17 responses in the spleen but not in the lymph nodes, blockade of platelet-Tn cell contact diminished platelet effects, while spleen injection of PF4-immobilized microparticles in PF4-deficient mice mimicked platelet effects, suggesting the importance of direct platelet-Tn contact and platelet-bound PF4 for the optimal regulatory effects by platelets. CONCLUSION: Platelets exert context-dependent regulations on effector responses of Tn cells via PF4-TGFß duet, suggesting new possibilities of platelet-targeted interventions of T cell immunity.

Photophosphatidylserine Guides Natural Killer Cell Photoimmunotherapy via Tim-3.

Natural killer (NK) cells, in addition to their cytotoxicity function, harbor prominent cytokine production capabilities and contribute to regulating autoimmune responses. T-cell immunoglobulin and mucin domain containing protein-3 (Tim-3) is one of the inhibitory receptors on NK cells and a promising immune checkpoint target. We recently found that phosphatidylserine (PS) binding to Tim-3 can suppress NK cell activation. Therefore, based on the therapeutic potential of Tim-3 in NK-cell-mediated diseases, we developed a photoswitchable ligand of Tim-3, termed photophosphatidylserine (phoPS), that mimics the effects of PS. Upon 365 or 455 nm light irradiation, the isomer of phoPS cyclically conversed the cis/trans configuration, resulting in an active/inactive Tim-3 ligand, thus modulating the function of NK cells in vitro and in vivo. We also demonstrated that reversible phoPS enabled optical control of acute hepatitis. Together, phoPS may be an appealing tool for autoimmune diseases and cytokine storms in the future.

ZHX2 inhibits thyroid cancer metastasis through transcriptional inhibition of S100A14.

BACKGROUND: Thyroid cancer is the most common malignant endocrine tumour, and metastasis has become the main reason for treatment failure. However, the underlying molecular mechanism of thyroid cancer metastasis remains poorly understood. We investigated the role of the tumour suppressor zinc fingers and homeoboxes 2 (ZHX2) in the metastasis of thyroid cancer. METHODS: To study the role of ZHX2 in thyroid cancer metastasis, we evaluated the EMT process using cell migration, wound healing and lung metastatic tumour formation in vitro and in vivo models. RESULTS: ZHX2 expression was significantly decreased in thyroid cancer tissues, which correlated with poor prognosis of thyroid cancer patients. ZHX2 knockdown significantly promoted the migration of thyroid cancer cells. Mechanistically, ZHX2 associated with the S100 calcium binding protein A14 (S100A14) promoter to decrease the transcription of S100A14. Moreover, S100A14 was highly expressed in human thyroid cancer samples, and its expression negatively correlated with ZHX2 expression. CONCLUSIONS: Inhibition of S100A14 attenuated the ZHX2 knockdown-induced enhanced metastasis of thyroid cancer cells both in vitro and in vivo. The evidence presented here suggests that ZHX2 inhibits the progression of thyroid cancer by blocking S100A14-mediated metastasis.

Zhx2 Accelerates Sepsis by Promoting Macrophage Glycolysis via Pfkfb3.

Sepsis is a life-threatening condition with limited therapeutic options, characterized as excessive systemic inflammation and multiple organ failure. Macrophages play critical roles in sepsis pathogenesis. Metabolism orchestrates homeostasis of macrophages. However, the precise mechanism of macrophage metabolism during sepsis remains poorly elucidated. In this study, we identified the key role of zinc fingers and homeoboxes (Zhx2), a ubiquitous transcription factor, in macrophage glycolysis and sepsis by enhancing 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (Pfkfb3) expression. Mice with myeloid Zhx2-specific deletion (abbreviated as MKO) showed more resistance to cecal ligation and puncture and LPS-induced sepsis, exhibiting as prolonged survival, attenuated pulmonary injury, and reduced level of proinflammatory cytokines, such as TNF-α, IL-6, and IL-1ß. Interestingly, Zhx2 deletion conferred macrophage tolerance to LPS-induced glycolysis, accompanied by reduced proinflammatory cytokines and lactate. Consistently, treatment of glycolytic inhibitor 2-deoxyglucose almost completely abrogated the protection of mice from LPS-induced sepsis initiated by Zhx2 deletion in macrophages. RNA sequencing and chromatin immunoprecipitation assays confirmed that Zhx2 enhanced transcription of Pfkfb3, the glycolysis rate-limiting enzyme, via binding with Pfkfb3 promoter. Furthermore, Pfkfb3 overexpression not only rescued the reduction of macrophage glycolysis caused by Zhx2 deficiency, displaying as extracellular acidification rates and lactate production but also destroyed the resistance of mice to LPS-induced sepsis initiated by transfer of bone marrow-derived macrophages from MKO mice. These findings highlight the novel role of transcription factor Zhx2 in sepsis via regulating Pfkfb3 expression and reprogramming macrophage metabolism, which would shed new insights into the potential strategy to intervene sepsis.

Platelets enhance CD4+ central memory T cell responses via platelet factor 4-dependent mitochondrial biogenesis and cell proliferation.

Platelets regulate multiple aspects of CD4+ T cell immunity, and may exert distinct regulations among different T cell subsets. Our aim was to investigate how platelets regulate CD4+ central memory T cell (Tcm) responses. αCD3/αCD28-stimulated human CD4+ Tcm cells were cultured without or with platelets or platelet-derived mediators. Polyclonal stimulation induced cell proliferation and Th1 and Treg cell activation of Tcm cells. Platelet factor 4/PF4 neutralization abolished platelet-enhanced Tcm effector responses, whilst TGFß neutralization only partially inhibited platelet-enhanced Treg cell activation. PF4 supplementation mimicked the effects of platelet co-cultures, while PF4 receptor CXCR3 blockade and CXCR3 knockdown with siRNAs inhibited or abolished PF4-enhanced Th1 and Treg cell responses. Platelet co-cultures or PF4-treatment increased Tcm cell proliferation, whilst CXCR3 blockade counteracted. PF4-enhanced Tcm proliferation and effector cell responses were associated with mitochondrial biogenesis. Overexpression of mitochondrial transcription factor A (TFAM) mimicked PF4 effects, and PF4 treatment attenuated Akt phosphorylation of activated Tcm cells, leading to mitochondrial biogenesis. Impacts of platelets and PF4 on Tcm proliferation were further confirmed by that CXCR3 knockdown/blockade counteracted PF4-enhanced Tcm cell proliferation. In conclusion, platelets enhance Th1 and Treg cell responses of CD4+ Tcm cells, via PF4-dependent mitochondrial biogenesis and cell proliferation of Tcm cells.

Human leukocyte antigen-G upregulates immunoglobulin-like transcripts and corrects dysfunction of immune cells in immune thrombocytopenia.

Human leukocyte antigen-G (HLA-G) is a non-classical major histocompatibility complex class I antigen with potent immune-inhibitory function. HLA-G benefit patients in allotransplantation and autoimmune diseases by interacting with its receptors, immunoglobulinlike transcripts. Here we observed significantly less HLA-G in plasma from immune thrombocytopenia (ITP) patients positive for anti-platelet autoantibodies compared with autoantibodies-negative patients or healthy controls, while we found that HLA-G is positively correlated with platelet counts in both patients and healthy controls. We also found less membranebound HLA-G and immunoglobulin-like transcripts on CD4+ and CD14+ cells in patients. Recombinant HLA-G upregulated immunoglobulin-like transcript 2 expression on CD4+ and immunoglobulin-like transcript 4 on CD14+ cells. HLA-G upregulated IL-4 and IL-10, and downregulated tumor necrosis factor-a, IL-12 and IL-17 secreted by patient peripheral blood mononuclear cells, suggesting a stimulation of Th2 differentiation and downregulation of Th1 and Th17 immune response. HLA-G-modulated dendritic cells from ITP patients showed decreased expression of CD80 and CD86, and suppressed CD4+ T-cell proliferation compared to unmodulated cells. Moreover, HLA-G-modulated cells from patients induced less platelet apoptosis. HLA-G administration also significantly alleviated thrombocytopenia in a murine model of ITP. In conclusion, our data demonstrated that impaired expression of HLA-G and immunoglobulin-like transcripts is involved in the pathogenesis of ITP; recombinant HLA-G can correct this abnormality via upregulation of immunoglobulin-like transcripts, indicating that HLA-G can be a diagnostic marker and a therapeutic option for ITP.

Halorubrum salipaludis sp. nov., isolated from the saline-alkaline soil.

A novel extremely halophilic archaeon, designated WN019T, was isolated from the natural saline-alkali wetland soil of Binhai new district, Tianjin, China. Cells of WN019T were aerobic, motile, and pleomorphic rod-shaped, 0.5-0.8 µm in width and 2.0-2.5 µm in length, and the growth occurred optimally at 33-37 °C, pH 7.5-8.0, and in the presence of 15.0-20.0% (w/v) NaCl. Phylogenetic analyses based on 16S rRNA gene sequence comparison showed that the isolate belonged to the genus Halorubrum and exhibited moderate sequence similarity of 97.8% to Halorubrum saccharovorum JCM 8865T. The major respiratory quinones of strain WN019T were MK-8 and MK-8 (H2), and the major polar lipids were glycolipid (GL), phospholipid (PL), phosphatidylglycerol-sulphate (PGS), phosphatidylglycerol (PG) and phosphatidylglycerol-phosphate-methyl ester (Me-PGP). The DNA G + C content of the strain was 67.4 mol%. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) value based on whole genome sequences of strain WN019T and Halorubrum saccharovorum JCM 8865T were 87.5% and 35.4%, respectively. Phenotypic, chemotaxonomic, phylogenetic, and genomic analyses suggested that strain WN019T represents a novel species of the genus Halorubrum, for which the name Halorubrum salipaludis sp. nov. is proposed. The type strain is WN019T (= KCTC 4269T = ACCC 19977T).

ZHX2 inhibits SREBP1c-mediated de novo lipogenesis in hepatocellular carcinoma via miR-24-3p.

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide. Lipogenesis has been considered as a critical player in HCC initiation and progression. However, the underlying mechanism is still not fully understood. Here, we identified zinc fingers and homeoboxes 2 (ZHX2), an HCC-associated tumor suppressor, as an important repressor of de novo lipogenesis. Ectopic expression of ZHX2 significantly inhibited de novo lipogenesis in HCC cells and decreased expression of FASN, ACL, ACC1, and SCD1. In accordance with this, ZHX2 was negatively associated with SREBP1c, the master regulator of de novo lipogenesis, in HCC cell lines and human specimens. Results from silencing and overexpression demonstrated that ZHX2 inhibited de novo lipogenesis and consequent HCC progression via repression of SREBP1c. Furthermore, treatment with the SREBP1c inhibitor fatostatin dampened the spontaneous formation of tumors in liver-specific Zhx2 knockout mice. Mechanistically, ZHX2 increased expression of miR-24-3p transcriptionally, which targeted SREBP1c and led to its degradation. In conclusion, our data suggest a novel mechanism through which ZHX2 suppresses HCC progression, which may provide a new strategy for the treatment of HCC. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Tim-4 Inhibits NLRP3 Inflammasome via the LKB1/AMPKα Pathway in Macrophages.

Nonalcoholic fatty liver disease (NAFLD), characterized by excessive inflammation and lipid deposition, is one of the most common metabolic liver diseases. The expression of NLRP3 inflammasome in macrophages is significantly increased in NAFLD, and its activation aggravates NAFLD greatly. Tim-4, as the phosphatidylserine (PS) receptor, is expressed highly in macrophages, and macrophage Tim-4 inhibits inflammation under various conditions of immune activation. However, the precise role of Tim-4 in NLRP3 inflammasome regulation and NAFLD pathogenesis remains completely unknown. Using NAFLD mice models, we confirmed that the expression of Tim-4 was increased in liver tissues by Western blot, real-time PCR, immunohistochemistry, and immunofluorescence, especially higher expression in liver macrophages, and Tim-4 knockout mice displayed more severe liver inflammation and hepatic steatosis than controls in NAFLD mice model. In vitro, we found that Tim-4 could inhibit NLRP3 inflammasome activation, and the inhibition was dependent on PS binding domain in the IgV domain. Mechanistically, Tim-4 induced the degradation of NLRP3 inflammasome components through activating AMPKα-mediated autophagy. Specifically, Tim-4 promoted AMPKα phosphorylation by interacting with LKB1 and AMPKα. In addition, PS binding motif was responsible for Tim-4-mediated AMPKα and LKB1 interaction. In conclusion, NAFLD microenvironments upregulate Tim-4 expression in macrophages, and elevated Tim-4, in turn, suppresses NLRP3 inflammasome activation by activating LKB1/AMPKα-mediated autophagy, thereby ameliorating the release of IL-1ß and IL-18. Collectively, this study unveils the novel function of Tim-4 in suppressing NLRP3 inflammasome, which would shed new lights on intervention of NAFLD or inflammatory liver diseases by targeting Tim-4.

Long-term coexistence of SARS-CoV-2 with antibody response in COVID-19 patients.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causing coronavirus disease 2019 (COVID-19) has spread worldwide. Whether antibodies are important for the adaptive immune responses against SARS-CoV-2 infection needs to be determined. Here, 26 cases of COVID-19 in Jinan, China, were examined and shown to be mild or with common clinical symptoms, and no case of severe symptoms was found among these patients. Strikingly, a subset of these patients had SARS-CoV-2 and virus-specific IgG coexist for an unexpectedly long time, with two cases for up to 50 days. One COVID-19 patient who did not produce any SARS-CoV-2-bound IgG successfully cleared SARS-CoV-2 after 46 days of illness, revealing that without antibody-mediated adaptive immunity, innate immunity alone may still be powerful enough to eliminate SARS-CoV-2. This report may provide a basis for further analysis of both innate and adaptive immunity in SARS-CoV-2 clearance, especially in nonsevere cases.