Primary Biliary Cholangitis (PBC) is an organ-specific autoimmune liver disease. Mononuclear phagocytes (MNPs), comprise of monocyte, dendritic cells and monocyte-derived macrophages, constitute ...major arm of the innate immune system known to be involved in the pathogenesis of autoimmune disorders. MNPs were shown to accumulate around intra-hepatic bile ducts in livers of PBC patients. Interleukin 23 (IL-23) is a pro-inflammatory cytokine. IL-23-positive cells were detected in livers of patients with advanced stage PBC and IL-23 serum levels found to be in correlation with PBC disease severity. Our overall goal was to assess the importance of IL-23 derived from MNPs in PBC pathogenesis.
We utilized an inducible murine model of PBC and took advantage of transgenic mice targeting expression of IL-23 by specific MNP populations. Analysis included liver histology assessment, flow cytometry of hepatic immune cells and hepatic cytokine profile evaluation. Specific MNPs sub-populations were sorted and assessed for IL-23 expression levels.
Flow cytometry analysis of non-parenchymal liver cells in autoimmune cholangitis revealed massive infiltration of the liver by MNPs and neutrophils and a decrease in Kupffer cells numbers. In addition, a 4-fold increase in the incidence of hepatic IL-17A producing CD4
T cells was found to be associated with an increase in hepatic IL23-p19 and IL17A expression levels. Disease severity was significantly ameliorated in both CD11c
P19
and CX
CR1
P19
mice as assessed by reduced portal inflammation and decreased hepatic expression of various inflammatory cytokines. Amelioration of disease severity was associated with reduction in IL-17A producing CD4
T cells percentages and decreased hepatic IL23-p19 and IL17A expression levels. qRT-PCR analysis of sorted hepatic MNPs demonstrated high expression levels of IL-23 mRNA specifically by CX
CR1
CD11c
monocyte-derived macrophages.
Our results indicate a major role for IL-23 produced by hepatic monocyte-derived macrophages in the pathogenesis of PBC. These results may pave the road for the development of new immune-based and cell specific therapeutic modalities for PBC patients not responding to current therapies.
Background Intraductal papillary mucinous neoplasms (IPMN) represent a spectrum of tumors that range from low-grade (LG) dysplastic tumors to invasive cancer. Identification of IPMN at high risk for ...malignant transformation is important for the prevention and early treatment of pancreatic cancer. The roles of microRNA expression in the development of IPMN have not been extensively evaluated. Methods Expression patterns of 846 human microRNAs (miRNAs) was analyzed using microRNA microarray in 55 tissues, including LG IPMN ( n = 10), moderate-grade (MG) IPMN ( n = 5), high-grade (HG) IPMN ( n = 5), invasive cancer with IPMN (IPMC; n = 10), pancreatic ductal adenocarcinoma without IPMN (PDA; n = 5), LG IPMN extracted from specimens that contain IPMC (LG_Ca; n = 10), and normal pancreatic tissues ( n = 10). Results Fourteen miRNAs were differentially expressed in all IPMN tissues compared with normal pancreatic tissue. Expression level of 3 miRNAs was proportional to dysplasia level. Hierarchical clustering demonstrated grouping of 2 IPMN subgroups: LG and MG IPMN verses HG IPMN and IPMC. Expression of 15 miRNAs was significantly different between these groups. LG_Ca tissues clustered with the HG IPMC group, and 12 miRNAs were differentially expressed in LG_Ca, HG lesions, and IPMC compared with LG lesions. The expression patterns of selected miRNAs were validated using quantitative reverse-transcription real-time polymerase chain reaction. Hierarchical clustering demonstrated microRNA expression profile in IPMC was significantly different from PDA, suggesting that different pathways are involved in these cancer types. Conclusion This study demonstrates that miRNAs are involved in the development and progression of IPMN. We identified potential targets for diagnosis, prognostication, and treatment of IPMN.
Liver-resident macrophages Kupffer cells (KCs) and infiltrating Ly6Chi monocytes both contribute to liver tissue regeneration in various pathologies but also to disease progression upon disruption of ...orderly consecutive regeneration cascades. Little is known about molecular pathways that regulate their differentiation, maintenance, or inflammatory behavior during injury. Here, we show that copper metabolism MURR1 domain (COMMD)10-deficient KCs adopt liver-specific identity. Strikingly, COMMD10 deficiency in KCs and in other tissue-resident macrophages impedes their homeostatic survival, leading to their continuous replacement by Ly6Chi monocytes. While COMMD10 deficiency in KCs mildly worsens acetaminophen-induced liver injury (AILI), its deficiency in Ly6Chi monocytes results in exacerbated and sustained hepatic damage. Monocytes display unleashed inflammasome activation and a reduced type I interferon response and acquire “neutrophil-like” and lipid-associated macrophage differentiation fates. Collectively, COMMD10 appears indispensable for KC and other tissue-resident macrophage survival and is an important regulator of Ly6Chi monocyte fate decisions and reparative behavior in the diseased liver.
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•COMMD10 deficiency impedes liver Kupffer cell homeostatic survival•COMMD10 is crucial for the survival of diverse tissue-resident macrophages•COMMD10 restrains the hepatotoxic activity of Ly6Chi monocytes in the injured liver•COMMD10 deficiency skews monocyte differentiation toward NeuMos and LAMs
Cohen et al. demonstrate a pivotal role for COMMD10 in homeostatic maintenance of Kupffer cells and other resident macrophages. COMMD10 is also involved in dictating Ly6Chi monocyte differentiation fates and restraining their inflammatory activity in the injured liver.
Background:
Inflammatory bowel disease (IBD) is characterized by increased lymphocytic infiltrate to the lamina propria (LP) and upregulation of inflammatory chemokines and receptors. CXCL12 is a ...constitutive chemokine involved in lung, brain, and joint inflammation. We hypothesized that CXCL12 and its receptor, CXCR4, would have a constitutive and inflammatory role in the gut.
Methods:
Intestinal epithelial cells (IECs) and T lymphocytes were isolated from intestinal mucosa of IBD and control patients undergoing bowel resection. Autologous T cells were isolated from peripheral blood (PB). CXCL12 and CXCR4 expression by IECs was assessed by polymerase chain reaction and immunohistochemistry, lymphocyte phenotype by flow cytometry, and migration by Transwells.
Results:
IECs expressed CXCL12 and expression was increased and more diffuse in IBD compared to normal crypts (ulcerative colitis UC > Crohn's disease CD, inflamed > noninflamed). CXCR4 was expressed by IECs, LP T cells (LPTs), and PB T cells (PBTs), and CXCR4+ cells were increased in IBD LP in situ. PBTs and LPTs from all patients had a high and comparable migration toward CXCL12 (P < 0.0001 and P < 0.05 vs. medium, respectively). Migration toward IBD‐IEC‐derived supernatant was significantly higher compared to normal. Antibodies against CXCR4 and CXCL12 blocked migration.
Conclusions:
CXCL12 is expressed by normal IECs and upregulated and differentially distributed in IBD IECs. CXCR4 is expressed by IECs and LPTs, and CXCR4+ cells are significantly increased in IBD LP. CXCL12 is chemotactic for both PBTs and LPTs. Thus, CXCL12 and CXCR4 have a constitutive and inflammatory role in the intestinal mucosa and their selective therapeutic manipulation may be considered in IBD management. (Inflamm Bowel Dis 2009;)
Leptin signaling is involved in T‐cell polarization and is required for profibrotic function of hepatic stellate cells (HSCs). Leptin‐deficient ob/ob mice do not develop liver fibrosis despite the ...presence of severe long‐standing steatohepatitis. Here, we blocked leptin signaling with our recently generated mouse leptin antagonist (MLA), and examined the effects on chronic liver fibrosis in vivo using the chronic thioacetamide (TAA) fibrosis model, and in vitro using freshly‐isolated primary HSCs. In the chronic TAA fibrosis model, leptin administration was associated with significantly enhanced liver disease and a 100% 5‐week to 8‐week mortality rate, while administration or coadministration of MLA markedly improved survival, attenuated liver fibrosis, and reduced interferon γ (IFN‐γ) levels. No significant changes in weight, serum cholesterol, or triglycerides were noted. In vitro administration of rat leptin antagonist (RLA), either alone or with leptin, to rat primary HSCs reduced leptin‐stimulated effects such as increased expression of α‐smooth muscle actin (α‐SMA), and activation of α1 procollagen promoter. Conclusion: Inhibition of leptin‐enhanced hepatic fibrosis may hold promise as a future antifibrotic therapeutic modality. (HEPATOLOGY 2009;49:278‐286.)
Solid pseudopapillary neoplasm (SPN) of pancreas is a rare pancreatic neoplasm with a low metastatic potential. Up to 10% of patients with localized disease at presentation will develop systemic ...metastases, usually in the peritoneum or the liver. Due to the rarity of SPNs and the overall excellent prognosis, reliable prognostic factors to predict malignant biological behavior remain undetermined. Therefore, we aimed to define clinical, histological, and microRNA patterns that are associated with metastatic disease. We conducted a retrospective single center study on all patients operated for SPN of pancreas between 1995 and 2018. Clinical and pathological data were collected, and expression patterns of 2,578 human microRNAs were analyzed using microRNA array (Affimetrix 4.1) in normal pancreases (NPs), localized tumors (LTs), and metastatic tumors (MTs). The diagnosis of SPN was confirmed in 35 patients who included 28 females and 3 males, with a mean age of 33.8 ± 13.9 years. The only clinical factor associated with metastases was tumor size (mean tumor size 5.20 ± 3.78 in LT vs. 8.13± 1.03 in MT,
< 0.012). Microscopic features of malignancy were not associated with metastases, nor were immunohistochemical stains, including the proliferative index KI67. Higher expressions of miR-184, miR-10a, and miR-887, and lower expressions of miR-375, miR-217, and miR-200c were observed in metastatic tissues on microarray, and validated by real-time polymerase chain reaction. Hierarchal clustering demonstrated that the microRNA expression pattern of MTs was significantly different from that of LTs. The only clinical factor associated with metastases of SPN of pancreas was tumor size. Histological features and immunohistological staining were not predictive of metastases. A panel of six microRNAs was differentially expressed in MTs, and these findings could potentially be used to predict tumor behavior. Validation of these results is needed in larger series.
The therapy of primary biliary cholangitis (PBC) has lagged behind other autoimmune diseases despite significant improvements in our understanding of both immunological and molecular events that lead ...to loss of tolerance to the E2 component of pyruvate dehydrogenase, the immunodominant autoepitope of PBC. It is well known that Ly6C
monocytes are innate immune cells infiltrating inflammatory sites that are dependent on the expression of C-C motif chemokine receptor 2 (CCR2) for emigration from bone marrow. Importantly, humans with PBC have a circulating monocyte pro-inflammatory phenotype with macrophage accumulation in portal tracts. We have taken advantage of an inducible chemical xenobiotic model of PBC and recapitulated the massive infiltration of monocytes to portal areas. To determine the clinical significance, we immunized both CCR2-deficient mice and controls with 2OA-BSA and noted that CCR2 deficiency is protective for the development of autoimmune cholangitis. Importantly, because of the therapeutic potential, we focused on inhibiting monocyte infiltration through the use of cenicriviroc (CVC), a dual chemokine receptor CCR2/CCR5 antagonist shown to be safe in human trials. Importantly, treatment with CVC resulted in amelioration of all aspects of disease severity including serum total bile acids, histological severity score, and fibrosis stage. In conclusion, our results indicate a major role for Ly6C
monocytes and for CCR2 in PBC pathogenesis and suggest that inhibition of this axis by CVC should be explored in humans through the use of clinical trials.
Differential regulation of CXCL12 receptors is suggested as mechanism to modulate T cells function in mucosal homeostasis and inflammation.
IBDs are characterized by increased influx of immune cells ...to the mucosa of genetically susceptible persons. Cellular migration to injury sites is mediated by chemokines. CXCL12 is a ubiquitous, constitutive chemokine that participates in stem cell proliferation and migration and mediates T lymphocyte migration to inflamed tissues. We have recently reported that CXCL12 and its receptor, CXCR4, are expressed in normal and more prominently, inflamed human intestinal mucosa. However, the interactions and roles of CXCL12 and its receptors, CXCR4 and the recently discovered CXCR7, in intestinal inflammation have not been defined. In the present study, we further dissected the effects of CXCL12 on lymphocytes in intestinal homeostasis and inflammation and delineated the interplay between CXCL12 and its receptors CXCR4 and CXCR7. To that end, fresh mononuclear cells were isolated from mucosa and PB of healthy or IBD patients. Phenotypical and functional assays were conducted using flow cytometry, Transwell migration chambers, and ELISA. The data show that CXCL12‐mediated migration of T cells is CXCR4‐ but not CXCR7‐dependent. T cell activation reciprocally regulates CXCR7 and CXCR4 expression and migratory capacity. IBD PBTs expressed more CXCR7 than normal PBTs. Finally, T cells attracted by CXCL12 are mostly of a memory phenotype. In conclusion, the present study suggests that the interplay between CXCL12 and its receptors affects homeostasis and inflammation in the intestinal mucosa.
Background
CCAAT/enhancer‐binding protein β (C/EBPβ) is a transcription factor known to be involved in macrophage differentiation and function, steatohepatitis and liver fibrosis.
Methods
Immune ...restricted C/EBPβ deficient and control mice were investigated in steady‐state and in the CDA‐HFD steatohepatitis model. Mice were assessed for weight change, liver biochemical profile, histology and hepatic phagocytes composition.
Results
Flow cytometry analysis of hepatic nonparenchymal cells revealed reduced numbers of hepatic monocytes and Kupffer cells and an increase in hepatic MHC class II positive myeloid cells in immune cells restricted C/EBPβ deficient mice. Immune‐restricted C/EBPβ deficiency resulted in decreased weight gain and appearance of mild spontaneous liver inflammation. Nevertheless, In the CDA‐HFD steatohepatitis model, immune restricted C/EBPβ deficient and proficient mice exhibit similar grade of hepatic steatosis, liver enzymes levels and fibrosis stage.
Conclusions
Immune‐restricted C/EBPβ deficiency leads to significant alteration in hepatic mononuclear phagocytes composition associated with spontaneous mild hepatitis. Steatohepatitis associated fibrosis is not dependent on C/EBPβ expression by immune cells.
Investigating the liver of immune restricted C/EBPβ‐deficient mice revealed major alteration in the composition of the intra‐hepatic myeloid cells pool associated with mild spontaneous hepatitis. Yet, immune cell restricted C/EBPβ‐deficiency did not confer protection from hepatic steatosis, inflammation and fibrosis, that are suggested to be influenced by C/EBPβ expression in nonimmune cells.
Background High rates of extrapancreatic malignancies (EPM) have been observed in patients with intraductal papillary mucinous neoplasm (IPMN). IPMN in patients with familial pancreatic cancer have ...also been reported. Our purpose was to evaluate the association of IPMN with EPM, malignancies in family members, and germline BRCA1 and BRCA2 mutations. Methods Using retrospective analysis on prospectively collected data from 82 patients with IPMN and direct contact for familial cancer history, data were compared with those of 150 patients with pancreatic ductal adenocarcinoma (PDAC). The common germline mutations in the BRCA1 and BRCA2 genes were evaluated on available IPMN patients. Results EPM rates were greater in IPMN than PDAC patients ( P = .002). Malignancies in first-degree relatives, specifically pancreatic cancer, were more common among IPMN than PDAC patients ( P = .028). IPMN patients with EPM had high rates of relatives with colorectal cancer (31%). Two of the 51 genetically tested patients (4%) were BRCA2 mutation carriers, and both had first-degree relatives with pancreatic cancer. One patient fulfilled the Amsterdam criteria for hereditary nonpolyposis colon cancer; however, the neoplasm was microsatellite stable. Conclusion Our results demonstrated high rates of EPM among IPMN patients. There was an increased rate of cancer in families of IPMN patients, specifically pancreatic cancer. A high rate of colorectal cancer in families of IPMN patients who have EPM was also observed. These findings suggest a genetic component in the pathogenesis of IPMN. Possible genetic changes include BRCA2 mutations, which are found in 25% of IPMN patients with a family history of pancreatic cancer.
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