Anti-B7-H3 monoclonal antibody ameliorates the damage of acute experimental pancreatitis by attenuating the inflammatory response

Decrease of Membrane B7-H5 on CD14+ Cells in Severe Acute Pancreatitis Is Related to RANSON Scores and APACHE II Scores

BACKGROUND

B7-H5 is an important ligand which is deeply involved in the immune response in various diseases. However, its clinical usefulness as an early indicator in acute pancreatitis (AP) remains unclear.

AIMS

To determine the role of B7-H5 in severe acute pancreatitis (SAP).

METHODS

Whole blood samples from patients with SAP (n = 20) and healthy donors (n = 20) were collected. Expression of soluble B7-H5 (sB7-H5) in plasma was determined by ELISA and membrane B7-H5 (mB7-H5) on the peripheral CD14+ cells was determined by flow cytometry. Peripheral blood mononuclear cells (PBMCs) were isolated from healthy donors and stimulated with serum from SAP patients, lipopolysaccharide (LPS), TNF-α, or IFN-γ, then, sB7-H5 and mB7-H5 were measured. The relationship between expression levels of mB7-H5 and clinical features of SAP patients were analyzed.

RESULTS

The expression levels of sB7-H5 in plasma were increased and the expression levels of mB7-H5 on the peripheral CD14+ cells were decreased in SAP patients. These changes of B7-H5 expression pattern in cultured PBMCs could be induced by stimulation with serum from SAP patients, LPS, TNF-α, or IFN-γ. Expression levels of mB7-H5 were negatively related to levels of hematocrit, urea nitrogen, creatinine, lactic acid, RANSON scores, and APACHE II scores.

CONCLUSION

Changes of B7-H5 expression pattern were involved in immune response of SAP. Innate immunity activation-induced decrease of mB7-H5 might be related to poor prognosis of SAP patients.

Dysregulated B7H4/JAK2/STAT3 Pathway Involves in Hypertriglyceridemia Acute Pancreatitis and Is Attenuated by Baicalin

BACKGROUND

Patients with hypertriglyceridemia (HTG) are prone to develop more severe acute pancreatitis (AP). However, the specific molecular mechanism still has not been elaborated clearly, and effective drugs for treating HTG-AP are not yet readily available. Baicalin is an ingredient isolated from a natural product that with potential to attenuate inflammation and pain in AP.

AIMS

The aim of the present study was to explore the effect of baicalin on HTG-AP and the possible mechanism involved.

METHODS

A mouse model of HTG-AP was successfully established by administering Poloxamer 407 and L-arginine intraperitoneally. We analyzed pathological changes, and performed TUNEL staining, DHE staining, and western blot to detect apoptosis, inflammation, oxidative stress, and B7H4/JAK2/STAT3 signaling in the pancreas.

RESULTS

Treatment with baicalin decreased serum triglyceride, cholesterol, lipase, amylase levels, and attenuated pancreatic edema. After intervention with baicalin, apoptosis and inflammation in HTG-AP mice were alleviated, as indicated by the decrease of Bax, cleaved-caspase-3, IL-6, TNF-α, and IL-1β. Baicalin also alleviated oxidative stress by decreasing NOX2, increasing SOD2 protein expression, and regulating Nrf2/Keap1 signaling in HTG-AP mice. Furthermore, baicalin decreased the upregulated B7H4/JAK2/STAT3 pathway in HTG-AP.

CONCLUSIONS

In conclusion, our data suggested that baicalin could attenuate HTG-AP, possibly through regulating B7H4/JAK2/STAT3 signaling.

Soluble B7-H5 Is a Novel Diagnostic, Severity, and Prognosis Marker in Acute Pancreatitis

As an important ligand in T lymphocyte costimulatory pathways, B7-H5 is involved deeply in the immune response in various diseases. However, its clinical usefulness as an early indicator in acute pancreatitis (AP) remains unclear. In this study, the levels of sB7-H5 and cytokines in plasma samples of 75 AP patients, 20 abdominal pain patients without AP, and 20 healthy volunteers were determined. Then, the correlation of sB7-H5 and clinical features, cytokines, the Ranson score, APACHE II score, Marshall score, and BISAP score was analysed, and the value of sB7-H5 for diagnostic, severity, and prognosis of AP was evaluated. We found that the levels of sB7-H5 were specifically upregulated in AP patients. Receiver operating characteristic (ROC) analysis revealed that sB7-H5 can identify AP patients from healthy or abdominal pain patients with 78.9% or 86.4% sensitivity and 93.3% or 90.0% specificity. Further analysis showed that the levels of sB7-H5 were significantly correlated with WBC (p = 0.004), GLU (p = 0.008), LDH (p < 0.001), Ca²⁺ (p = 0.006), AST (p = 0.009), PLT (p = 0.041), IL-6 (p < 0.001), IL-10 (p < 0.001), and TNF-α (p < 0.001). And levels of sB7-H5 were gradually increased among patients with mildly acute pancreatitis (MAP), moderately severe acute pancreatitis (MSAP), and severe acute pancreatitis (SAP). It can distinguish the severity of AP with good sensitivity and specificity. Moreover, when dividing the patients into two groups according to the median level of sB7-H5, the local complication and length of stay of low levels of the sB7-H5 group were significantly less than those in high levels of the sB7-H5 group. And the levels of sB7-H5 in AP patients were significantly correlated with the Ranson score (p < 0.001), APACHE II score (p < 0.001), Marshall score (p < 0.001), and BISAP score (p < 0.001). The AUCs of assessing local complications of sB7-H5 at day 1 and day 3 were 0.704 (p = 0.0024) and 0.727 (p = 0.0373). These results showed the potential value of sB7-H5 as a diagnostic, severity, and prognosis marker of AP.

MicroRNA miR-29a Inhibits Colon Cancer Progression by Downregulating B7-H3 Expression: Potential Molecular Targets for Colon Cancer Therapy

MiR-29a belongs to one of the subtypes of miRNAs known as non-coding single-stranded RNAs and is preferentially expressed in normal tissues. B7-H3, a member of the B7/CD28 immunoglobulin superfamily, was shown to be overexpressed in several solid malignant tumors, including colon cancer. In addition, it is associated with tumor progression and poor prognosis. We used immunohistochemical and Western blotting to assess B7-H3 protein expression levels in colon cancer and adjacent normal tissues and then compared their relationships with clinicopathological factors. Quantitative real-time reverse-transcription PCR was used to assess B7-H3 and miRNA-29a mRNA expression levels, and then their relationship and clinical significance were evaluated. In addition, colon cancer Caco-2 cells, which constitutively overexpress B7-H3, were transfected with lentivirus particles for miR-29a upregulation. Invasion and migration assays were carried out in vitro along with the establishment of a subcutaneous xenograft model in vivo to determine the role of miRNA-29a in colon cancer progression. The B7-H3 protein showed elevated expression in colon carcinoma and was relevant to TNM staging, lymph node metastasis, and reduced survival. Meanwhile, miR-29a was preferentially expressed in normal colon tissues, while B7-H3 transcript levels had no marked differences between tumor and normal tissue specimens. In vitro, miR-29a upregulation resulted in reduced B7-H3 expression. Furthermore, miR-29a upregulation reduced the invasive and migratory abilities of colon carcinoma cells. In animal models, upregulation of miR-29a slowed down the growth of subcutaneous xenotransplanted tumors and resulted in prolonged survival time. MiR-29a downregulates B7-H3 expression and accordingly inhibits colon cancer progression, invasion, and migration, indicating miR-29a and B7-H3 might represent novel molecular targets for advanced immunotherapy in colon cancer.

The MDM2 ligand Nutlin-3 differentially alters expression of the immune blockade receptors PD-L1 and CD276

BACKGROUND

The links between the p53/MDM2 pathway and the expression of pro-oncogenic immune inhibitory receptors in tumor cells are undefined. In this report, we evaluate whether there is p53 and/or MDM2 dependence in the expression of two key immune receptors, CD276 and PD-L1.

METHODS

Proximity ligation assays were used to quantify protein-protein interactions in situ in response to Nutlin-3. A panel of p53-null melanoma cells was created using CRISPR-Cas9 guide RNA mediated genetic ablation. Flow cytometric analyses were used to assess the impact of TP53 or ATG5 gene ablation, as well as the effects of Nutlin-3 and an ATM inhibitor on cell surface PD-L1 and CD276. Targeted siRNA was used to deplete CD276 to assess changes in cell cycle parameters by flow cytometry. A T-cell proliferation assay was used to assess activity of CD4+ T-cells as a function of ATG5 genotype.

RESULTS

CD276 forms protein-protein interactions with MDM2 in response to Nutlin-3, similar to the known MDM2 interactors p53 and HSP70. Isogenic HCT116 p53-wt/null cancer cells demonstrated that CD276 is induced on the cell surface by Nutlin-3 in a p53-dependent manner. PD-L1 was also unexpectedly induced by Nutlin-3, but PD-L1 does not bind MDM2. The ATM inhibitor KU55993 reduced the levels of PD-L1 under conditions where Nutlin-3 induces PD-L1, indicating that MDM2 and ATM have opposing effects on PD-L1 steady-state levels. PD-L1 is also up-regulated in response to genetic ablation of TP53 in A375 melanoma cell clones under conditions in which CD276 remains unaffected. A549 cells with a deletion in the ATG5 gene up-regulated only PD-L1, further indicating that PD-L1 and CD276 are under distinct genetic control.

CONCLUSION

Genetic inactivation of TP53, or the use of the MDM2 ligand Nutlin-3, alters the expression of the immune blockade receptors PD-L1 and CD276. The biological function of elevated CD276 is to promote altered cell cycle progression in response to Nutlin-3, whilst the major effect of elevated PD-L1 is T-cell suppression. These data indicate that TP53 gene status, ATM and MDM2 influence PD-L1 and CD276 paralogs on the cell surface. These data have implications for the use of drugs that target the p53 pathway as modifiers of immune checkpoint receptor expression.

β-Arrestin1 alleviates acute pancreatitis via repression of NF-κBp65 activation

BACKGROUND AND AIM

β-Arrestins (β-arrs) are regulators and mediators of G protein-coupled receptor signaling that are functionally involved in inflammation. Nuclear factor-κB p65 (NF-κBp65) activation has been observed early in the onset of pancreatitis. However, the effect of β-arrs in acute pancreatitis (AP) is unclear. The aim of this study is to investigate whether β-arrs are involved in AP through activation of NF-κBp65.

METHODS

Acute pancreatitis was induced by either caerulein injection or choline-deficient supplemented with ethionine diet (CDE). β-arr1 wild-type and β-arr1 knockout mice were used in the experiment. The survival rate was calculated in the CDE model mice. Histological and western blot analyses were performed in the caerulein model. Inflammatory mediators were detected by real-time polymerase chain reaction in the caerulein-induced AP mice. Furthermore, AR42J and PANC-1 cell lines were used to further study the effects of β-arr1 in caerulein-induced pancreatic cells.

RESULTS

β-Arr1 but not β-arr2 is significantly downregulated in caerulein-induced AP in mice. Targeted deletion of β-arr1 notably upregulated expression of the pancreatic inflammatory mediators including tumor necrosis factor α and interleukin 1β as well as interleukin 6 and aggravated AP in caerulein-induced mice. β-Arr1 deficiency increased mortality in mice with CDE-induced AP. Further, β-arr1 deficiency enhanced caerulein-induced phosphorylation of NF-κBp65 both in vivo and in vitro.

CONCLUSION

β-Arr1 alleviates AP via repression of NF-κBp65 activation, and it is a potentially therapeutic target for AP.

The Prognostic Role of Peripheral Lymphocyte Subsets in Patients With Acute Pancreatitis

BACKGROUND

The prognostic role of peripheral lymphocyte subsets in early stage of acute pancreatitis (AP) is unknown.

METHODS

After enrollment, blood samples were collected in the first 24 hours of the onset of AP in 164 patients. The lymphocyte count and the percentage of CD3⁺, CD3⁺CD4⁺, CD3⁺CD8⁺, CD3^-CD19⁺and CD3^-CD (16 + 56)⁺ cells were assessed.

RESULTS

Reduction of the lymphocyte count and the percentage of CD3⁺CD8⁺ and CD3^-CD (16 + 56)⁺ cells within 24 hours of the onset of AP as well as an increase in the percentage of CD3⁺ and CD3⁺CD4⁺ cells were observed. The percentage of CD3^-CD (16 + 56)⁺ cells had the highest accuracy in prediction of AP severity.

CONCLUSIONS

Marked changes of the percentages of lymphocyte subset were found in peripheral blood in the early stage of AP. The percentage of CD3^-CD (16 + 56)⁺ cells in peripheral blood could be a potent prognostic predictor.

Substance P-regulated leukotriene B4 production promotes acute pancreatitis-associated lung injury through neutrophil reverse migration

Leukotriene B4 (LTB4) is a potent chemoattractant and inflammatory mediator involved in multiple inflammatory diseases. Substance P (SP) has been reported to promote production of LTB4 in itch-associated response in vivo and in some immune cells in vitro. Here, we investigated the role of LTB4 in acute pancreatitis (AP), AP-associated acute lung injury (ALI) and the related mechanisms of LTB4 production in AP. In vivo, murine AP model was induced by caerulein and lipopolysaccharide or L-arginine. The levels of LTB4 and its specific receptor BLT1 were markedly upregulated in both AP models. Blockade of BLT1 by LY293111 attenuated the severity of AP, decreased neutrophil reverse transendothelial cell migration (rTEM) into the circulation and alleviated the severity of ALI. In vitro, treatment of pancreatic acinar cells with SP increased LTB4 production. Furthermore, SP treatment increased phosphorylation of protein kinase C (PKC) α and mitogen activated protein kinases (MAPKs), including extracellular signal-regulated kinase (ERK), p-38 MAPK and c-Jun NH2-terminal kinase (JNK). Finally, blockade of neurokinin-1 receptor by CP96345 significantly attenuated the severity of AP and decreased the level of LTB4 when compared to AP group. In summary, these results show that SP regulates the production of LTB4 via PKCα/MAPK pathway, which further promotes AP-associated ALI through neutrophil rTEM.

Limitations and opportunities for immune checkpoint inhibitors in pediatric malignancies

Immune checkpoint inhibitors (ICI) have shown great promise in a wide spectrum of adult solid and hematological malignancies, achieving objective tumor responses and prolonging survival. However, there is limited clinical success amongst pediatric patients. In this review, we summarize the current understanding of ICI and present an up-to-date overview of recent and ongoing clinical trials of ICI in pediatric malignancies. In addition, we will discuss immunologic and clinical difficulties in this young population, as well as future prospects for combination of ICI with other immune-based and conventional treatments.

Role of phosphoinositide-3 kinase signaling pathways in pathogenesis of acute pancreatitis

Acute pancreatitis (AP) as a common acute disease poses a great threat to people's health. According to statistics, about one-fifth of cases develop acute respiratory distress syndrome and multiple organ dysfunction, which result in high mortality. The early understanding of the pathogenesis of this disease is limited to an inflammatory response resulting in autodigestion, edema, hemorrhage and necrosis of pancreatic tissue after the abnormal activation of trypsin. In recent years, researchers have focused their research on the role of immune inflammatory response in the pathogenesis of AP. Here we discuss the relationship between the immune inflammation and PI3K signaling pathways in AP.