Several observational studies have reported a correlation between the gut microbiota (GM) and the risk of acute pancreatitis (AP). However, the causal relationship between them remains uncertain. We conducted a 2-sample Mendelian randomization (MR) study using pooled data from genome-wide association studies of 211 taxa (131 genera, 35 families, 20 orders, 16 classes, and 9 phyla) and AP patients. We evaluated the causal relationship between the GM and AP using methods such as inverse-variance weighting, MR-Egger, weighted medians, simple mode, and weighted mode. Cochran Q test, MR-Egger regression intercept analysis, and MR-PRESSO were used to examine the heterogeneity, multipotency, and outlier values of the variables, respectively. The reverse causal relationship between AP and the GM was assessed with reverse MR. In total, 5 gut microbial taxa were significantly associated with AP. The inverse-variance weighting results indicated that Acidaminococcaceae (odds ratio [OR]: 0.81, 95% confidence interval [CI]: 0.66–1.00, P = .045) and Ruminococcaceae UCG004 (OR: 0.85, 95% CI: 0.72–0.99, P = .040) were protective factors against the occurrence of AP. Coprococcus 3 (OR: 1.32, 95% CI: 1.03–1.70, P = .030), Eisenbergiella (OR: 1.13, 95% CI: 1.00–1.28, P = .043), and the Eubacterium fissicatena group (OR: 1.18, 95% CI: 1.05–1.33, P = .006) were risk factors for the development of AP. A comprehensive sensitivity analysis proved our results to be reliable. Reverse MR analysis did not indicate any causal relationship between AP and the GM. This study revealed a complex causal relationship between 5 GM taxa and AP, providing new insights into the diagnostic and therapeutic potential of the GM in AP patients.

Background: Chronic inflammation caused by immune cells is the central link between obesity and insulin resistance. Targeting the inflammatory process is a highly promising method for reversing systemic insulin resistance. Methods: Blood samples were prospectively collected from 68 patients with type 2 diabetes. C57BL/6J mice were fed either a high-fat diet (HFD) or normal chow (NC). We performed phenotypical and functional analyses of immune cells using flow cytometry. Vitamin D receptor (VDR) knockout γδ T cells were constructed using Cas9-gRNA targeted approaches to identify 1α,25(OH)2D3/VDR signaling pathway-mediated transcriptional regulation of fructose-1,6-bisphosphatase (FBP1) in γδ T cells. Results: Serum vitamin D deficiency aggravates inflammation in circulating γδ T cells in type 2 diabetes patients. We defined a critical role for 1α,25(OH)2D3 in regulating glycolysis metabolism, protecting against inflammation, and alleviating insulin resistance. Mechanistically, 1α,25(OH)2D3-VDR promoted FBP1 expression to suppress glycolysis in γδ T cells, thereby inhibiting Akt/p38 MAPK phosphorylation and reducing inflammatory cytokine production. Notably, therapeutic administration of 1α,25(OH)2D3 restrained inflammation in γδ T cells and ameliorated systemic insulin resistance in obese mice. Conclusions: Collectively, these findings show that 1α,25(OH)2D3 plays an important role in maintaining γδ T cell homeostasis by orchestrating metabolic programs, and is a highly promising target for preventing obesity, inflammation, and insulin resistance.

Previous studies have demonstrated that T cell exhaustion is associated with poor clearance of Hepatitis B virus (HBV). However, whether the expression of exhaustion markers on innate-like circulating γδ T cells derived from patients with HBV infection correlates with the serum level of vitamin D is not completely understood. In this study, we found that the frequency of circulating Vδ2+ T cell and serum levels of vitamin 25(OH)D3 were significantly decreased in patients with HBV. And serum 25(OH)D3 levels in HBV-infected patients were negatively correlated with HBV DNA load and PD-1 expression on γδ T cells. Interestingly, 1α,25(OH)2 D3 alleviated the exhaustion phenotype of Vδ2 T cells in HBV-infected patients and promoted IFN-β expression in human cytotoxic Vδ2 T cells in vitro. Collectively, these findings demonstrate that vitamin D plays a pivotal role in reversing γδ T-cell exhaustion and is highly promising target for ameliorating HBV infection.

Recent studies have demonstrated that the antitumor immunity of immune cells can be modulated by gut microbiota and their metabolites. However, the underlying mechanisms remain unclear. Here, we showed that the serum butyric acid level is positively correlated with the expression of programmed cell death-1 (PD-1) on circulating CD8(+) and V?9 Vd2 (Vd2(+)) T cells in patients with non-small cell lung cancer (NSCLC). Responder NSCLC patients exhibited higher levels of serum acetic acid, propionic acid, and butyric acid than non-responders. Depletion of the gut microbiota reduces butyrate levels in both feces and serum in tumor-bearing mice. Mechanistically, butyrate increased histone 3 lysine 27 acetylation (H3K27ac) at the promoter region of Pdcd1 and Cd28 in human CD8(+) T cells, thereby promoting the expression of PD-1/CD28 and enhancing the efficacy of anti-PD-1 therapy. Butyrate supplementation promotes the expression of antitumor cytokines in cytotoxic CD8(+) T cells by modulating the T-cell receptor (TCR) signaling pathway. Collectively, our findings reveal that the metabolite butyrate of the gut microbiota facilitates the efficacy of anti-PD-1 immunotherapy by modulating TCR signaling of cytotoxic CD8 T cells, and is a highly promising therapeutic biomarker for enhancing antitumor immunity.

Endocrine therapy is considered as an effective strategy for estrogen and progestogen receptor (ER and PR)-positive breast cancer (BRCA) patients, whereas resistance to these agents is the major cause of BRCA mortality in women. Immune checkpoint receptor (ICR) blockade is another approach to treat BRCA, but the response rate of this approach for non-triple-negative breast cancer (non-TNBC) is relatively low. Recently, the androgen receptor (AR) has been identified as a tumor suppressor in ER-positive BRCA; however, the relationship between the levels of androgens and ICRs on T cells in BRCA is unclear. We observed that testosterone and dihydrotestosterone (DHT) in patients with HER2 and Luminal B were significantly lower than those in healthy controls, and the expression of AR has significant correlation with overall survival (OS) advantage for Luminal B patients. Moreover, testosterone and DHT were positively correlated with the PD-1 expression on Vδ1+ T cells in HER2 and Luminal B patients. These results suggest a potential approach of combining androgens with PD-1 blockade for treating HER2 and Luminal B breast cancer.

BackgroundEpidemiological surveys have revealed that low serum vitamin D level was correlated with increased risk of tumors. Dysfunctional T cells in patients with tumor are characterized as exhausted with high levels of immune checkpoint receptors (ICRs). However, whether the reduced level of vitamin D in patients with cancer correlates with cytotoxic T-cell exhaustion is unknown.MethodsPeriphery blood samples from 172 patients with non-small cell lung cancer (NSCLC) were prospectively collected. Patients with NSCLC received one course of intravenous docetaxel (75 mg/m2) followed by treatment with or without rocaltrol at a dose of 0.5–2.0 µg/day for total of 3 weeks. We performed phenotypical and functional analysis of T-cell through flow cytometry. Vitamin D receptor (VDR) knockout and overexpression CD8+and Vδ2+T cells were constructed using Cas9-gRNA targeted and overexpressing approaches to identify 1α,25(OH)2D3/VDR-mediated transcription regulation for ICRs or antitumor activity in T cells.ResultsWe show that serum level of vitamin D is negatively correlated with expression of programmed cell death-1 (PD-1), T-cell immunoreceptor with Ig and ITIM domains (TIGIT), and T-cell immunoglobulin and mucin-domain containing-3 (Tim-3), but positively correlated with CD28 expression on CD8+and Vγ9Vδ2+T cells in patients with NSCLC. 1α,25(OH)2D3, the active form of vitamin D, promotes the nuclear translocation of VDR, which binds to the promoter region ofPdcd1,Tim3, andTigitgenes and inhibits their expression. Besides, 1α,25(OH)2D3pretreatment also promotes the methylation of CpG island in the promoter region of thePdcd1gene and increases H3K27 acetylation at the promoter region of theCd28gene, which leads to surface PD-1 downregulation and CD28 upregulation, respectively. We further reveal that VDR-mediated Ca2+influx enhanced expression of Th1 cytokines via T-cell receptor activation. Functionally, 1α,25(OH)2D3pretreated CD8+T cells or Vγ9Vδ2+T cells showed increased Th1 cytokine production and enhanced antitumor immunity. Finally, oral 1α,25(OH)2D3could also decrease expression of PD-1, Tim-3, TIGIT and increase expression of CD28, resulting in cytokine production (associated with antitumor immunity) by cytotoxic T cells of patients with NSCLC.ConclusionsOur findings uncover the pleiotropic effects of 1α,25(OH)2D3in rescuing the exhausted phenotype of human cytotoxic T cells in patients with tumor and in promoting their antitumor immunity.Trial registration numberChiCTR2100051135.

Triple-negative breast cancer (TNBC) escape from immune-mediated destruction was associated with immunosuppressive responses that dampened the activation of tumor-infiltrating CD8 and γδ T cells. TNBC had a higher level of programmed cell death 1-ligand 1 (PD-L1) and indoleamine 2,3-dioxygenase (IDO), compared with other breast cancer subtypes. But, clinical studies have revealed that the response rate of PD-1/PD-L1 antibody for TNBC treatment was relatively low. However, the antitumor responses of human Vγ9Vδ2 T cells or IDO inhibitor in TNBC treatment are unknown. In this study, we found that IDO1 and PD-L1 were highly expressed in TNBC patients. Analysis of the clinical samples demonstrated that Vγ9Vδ2 T cells became exhausted in triple-negative breast cancer patients. And Vγ9Vδ2 T cells combined with αPD-L1 could not further enhance their antitumor responses in vitro and in vivo. However, Vγ9Vδ2 T cells combined with IDO1 inhibitor 1-Methyl-L-tryptophan (1-MT) or Lindrostat showed substantial inhibitory effects on MDA-MB-231 tumor cells. Finally, we found that IDO1 inhibitor promoted T cell’s cytotoxicity by enhancing perforin production. These results converged to suggest the potential application of Vγ9Vδ2 T cells treated with IDO1 inhibitor for TNBC therapy.

Epidemiological surveys have revealed that low serum vitamin D level was correlated with increased risk of tumors. Dysfunctional T cells in tumor patients are characterized as exhausted with high levels of immune checkpoint receptors (ICRs). However, whether the reduced level of vitamin D in cancer patients correlates with cytotoxic T cell exhaustion is unknown. Here, we show that serum level of vitamin D is negatively correlated with expression of PD-1, TIGIT, and Tim-3, but positively correlated with CD28 expression on CD8+ and Vγ9Vδ2+ T cells in patients with non-small cell lung cancer (NSCLC). 1α,25(OH)2D3, the active form of vitamin D, promotes the nuclear translocation of vitamin D receptor (VDR), which binds to the promoter region of Pdcd1, Tim3, Tigit genes and inhibits their expression. Besides, 1α,25(OH)2D3 pretreatment also promotes the methylation of CpG island in promoter region of Pdcd1 gene and increases H3K27 acetylation at promoter region of Cd28 gene, which leads to surface PD-1 down-regulation and CD28 up-regulation respectively. We further reveal that VDR-mediated Ca2+ influx enhanced expression of Th1 cytokines via T cell receptor activation. Functionally, 1α,25(OH)2D3 pretreated CD8+ T cells or Vγ9Vδ2+ T cells showed increased Th1 cytokines production and enhanced anti-tumor immunity. Finally, oral 1α,25(OH)2D3 could also decrease expression of PD-1, Tim-3, TIGIT and increase expression of CD28, resulting in cytokine production (associated with antitumor immunity) by cytotoxic T cells of patients with NSCLC. Collectively, our findings uncover the pleiotropic effects of 1α,25(OH)2D3 in rescuing exhausted phenotype of human cytotoxic T cells in tumor patients and promoting their anti-tumor immunity.

Psoriasis is a severe disease associated with the disturbance of metabolism and inflammation, but the molecular mechanisms underlying these aspects of psoriasis pathology are poorly understood. Here, we report that glutaminase 1-mediated (GLS1-mediated) glutaminolysis was aberrantly activated in patients with psoriasis and in psoriasis-like mouse models, which promoted Th17 and γδ T17 (IL-17A-producing γδ T) cell differentiation through enhancement of histone H3 acetylation of the Il17a promoter, thereby contributing to the immune imbalance and development of psoriasis. We further demonstrate that mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) protease was constitutively active in psoriatic CD4+ and γδ T cells, thereby supporting GLS1 expression by stabilizing c-Jun, which directly binds to the GLS1 promoter region. Blocking the activity of either GLS1 or MALT1 protease resolved Th17 and γδ T17 cell differentiation and epidermal hyperplasia in the psoriasis-like mouse models. Finally, IL-17A enhanced GLS1 expression via the MALT1/cJun pathway in keratinocytes, resulting in hyperproliferation of and chemokine production by keratinocytes. Our findings identify the role of the MALT1/cJun/GLS1/glutaminolysis/H3 acetylation/T17 axis in psoriasis pathogenesis and reveal potential therapeutic targets for this disease.

Purpose: To determine the effect of pristimerin on sepsis-induced lung injury, and the underlying mechanism of action.Methods: Lung injury was established in mice via induction of sepsis through cecal ligation and puncture (CLP). The effect of pristimerin was evaluated based on lung wet/dry weight and PaO2/FiO2 ratios. Lung tissue was subjected to immunohistochemical and histopathological analyses, as well as Western blotting. Furthermore, the serum levels of inflammatory mediators were determined.Results: Pristimerin reversed the altered lung wet/dry weight ratio and PaO2/FiO2 ratio in the lung, and also reduced lung injury score, relative to CLP group (p < 0.05). Moreover, it suppressed nucleocytoplasmic translocation of high mobility group protein B1 (HMGB1) in lung tissue. Serum levels of inflammatory mediators and expression levels of inducible nitric oxide synthase and nuclear factorkappaB p65 were significantly reduced by pristimerin (p < 0.05).Conclusion: Pristimerin ameliorates sepsis-induced lung injury by inhibiting HMGB1/NF-κB. Thus, this compound has a potential for clinical application in the management of lung injury. Keywords: Pristimerin, Sepsis, Lung injury, Inflammatory mediators, HMGB1

Spinal cord injury (SCI) is a devastating traumatic injury that causes persistent, severe motor and sensory dysfunction. Immune responses are involved in functional recovery after SCI. Mucosa-associated lymphoid tissue lymphoma translocation 1 (MALT1) has been shown to regulate the survival and differentiation of immune cells and to play a critical role in many diseases, but its function in lesion recovery after SCI remains unclear. In this paper, we generated KI (knock in) mice with a point mutation (C472G) in the active center of MALT1 and found that the KI mice exhibited improved functional recovery after SCI. Fewer macrophages were recruited to the injury site in KI mice and these macrophages differentiated into anti-inflammatory macrophages. Moreover, macrophages from KI mice exhibited reduced phosphorylation of p65, which in turn resulted in decreased SOCS3 expression and increased pSTAT6 levels. Similar results were obtained upon inhibition of MALT1 paracaspase with the small molecule inhibitor "MI-2" or the more specific inhibitor "MLT-827". In patients with SCI, peripheral blood mononuclear cells (PBMC) displayed increased MALT1 paracaspase. Human macrophages showed reduced pro-inflammatory and increased anti-inflammatory characteristics following the inhibition of MALT1 paracaspase. These findings suggest that inhibition of MALT1 paracaspase activity in the clinic may improve lesion recovery in subjects with SCI.

Background: Oxidized low-density lipoprotein (ox-LDL) has been well-documented to induce endothelial cell (EC) apoptosis and contribute to the progression of atherosclerosis. Kaempferol was reported to alleviate ox-LDL-induced apoptosis of human umbilical vein endothelial cells. However, the detailed mechanism by which kaempferol alleviated ox-LDL-induced EC apoptosis remains largely elusive. Methods: The expression of miR-26a-5p in human aortic endothelial cells (HAECs) treated with either ox-LDL alone or in combination with kaempferol was detected by qRT-PCR. Cell viability and apoptosis were assessed by MTT assay and flow cytometry, respectively. The interaction between miR-26a-5p and toll-like receptor 4 (TLR4) mRNA was examined by luciferase reporter assay. The protein levels of TLR4, phosphorylated-p65, p65, phosphorylated-I kappa B alpha and I kappa B alpha were determined by western blot. Results: Kaempferol upregulated miR-26a-5p expression in ox-LDL-stimulated HAECs. Moreover, kaempferol alleviated ox-LDL-induced apoptosis in HAECs by upregulating miR-26a-5p. Additionally, TLR4 mRNA was identified as a target of miR-26a-5p in ox-LDL-treated HAECs. TLR4 overexpression partially counteracted the anti-apoptotic role of miR-26a-5p in ox-LDL-treated HAECs. Furthermore, kaempferol inactivated the TLR4/nuclear factor kappa B (NF-kappa B) signaling pathway in ox-LDL-treated HAECs by upregulating miR-26a-5p. Conclusion: Kaempferol alleviated ox-LDL-induced apoptosis in HAECs by upregulating miR-26a-5p via inactivation of the TLR4/NF-kappa B signaling pathway, shedding light on the molecular mechanism by which kaempferol alleviated ox-LDL-induced EC apoptosis.

Previous studies have demonstrated that programmed death-1 ligand 1 (PD-L1) expressed in an aggressive activated B-cell (ABC)/non-germinal center B cell–like (GCB) subtype of diffuse large B-cell lymphoma (DLBCL) is associated with inhibition of the tumor-associated T cell response. However, the molecular mechanism underlying PD-L1 expression in ABC-DLBCL remains unclear. Here, we report that MALT1 protease activity is required for ABC-DLBCL cells to evade cytotoxity of Vγ9Vδ2 T lymphocytes by generating substantial PD-L1+ ABC-DLBCL cells. While, NF-κB was dispensable for the PD-L1 expression induced by MALT1 protease activity in ABC-DLBCL cells. Furthermore, we showed that GLS1 expression was profoundly reduced by MALT1 protease activity inhibition, which resulted in insufficiency of glutaminolysis-derived mitochondrial bioenergetics. Activation of the PD-L1 transcription factor STAT3, which was strongly suppressed by glutaminolysis blockade, was rescued in a TCA (tricarboxylic acid) cycle-dependent manner by glutamate addition. Collectively, MALT1 protease activity coupled with glutaminolysis-derived mitochondrial bioenergetics plays an essential role in PD-L1 expression on ABC-DLBCL cells under immunosurveillance stress. Thus, our research sheds light on a mechanism underlying PD-L1 expression and highlights a potential therapeutic target to vanquish immune evasion by ABC-DLBCL cells.