Induction of m2 polarization in primary culture liver macrophages from rats with acute pancreatitis

From pancreas to lungs: The role of immune cells in severe acute pancreatitis and acute lung injury

BACKGROUND

Severe acute pancreatitis (SAP) is a potentially lethal inflammatory pancreatitis condition that is usually linked to multiple organ failure. When it comes to SAP, the lung is the main organ that is frequently involved. Many SAP patients experience respiratory failure following an acute lung injury (ALI). Clinicians provide insufficient care for compounded ALI since the underlying pathophysiology is unknown. The mortality rate of SAP patients is severely impacted by it.

OBJECTIVE

The study aims to provide insight into immune cells, specifically their roles and modifications during SAP and ALI, through a comprehensive literature review. The emphasis is on immune cells as a therapeutic approach for treating SAP and ALI.

FINDINGS

Immune cells play an important role in the complicated pathophysiology ofSAP and ALI by maintaining the right balance of pro- and anti-inflammatory responses. Immunomodulatory drugs now in the market have low thepeutic efficacy because they selectively target one immune cell while ignoring immune cell interactions. Accurate management of dysregulated immune responses is necessary. A critical initial step is precisely characterizing the activity of the immune cells during SAP and ALI.

CONCLUSION

Given the increasing incidence of SAP, immunotherapy is emerging as a potential treatment option for these patients. Interactions among immune cells improve our understanding of the intricacy of concurrent ALI in SAP patients. Acquiring expertise in these domains will stimulate the development of innovative immunomodulation therapies that will improve the outlook for patients with SAP and ALI.

Myeloid-Derived Suppressor Cells in Patients With Acute Pancreatitis With Increased Inhibitory Function

Acute pancreatitis (AP) is pancreatic or systemic inflammation without or with motion organ dysfunction. Severe acute pancreatitis (SAP) is the main cause of death for patients with AP. A pro-/anti-inflammatory imbalance is considered the key regulation of disease severity. However, the real mechanism of SAP remains unclear. This study aimed to identify the frequency and specific roll of myeloid-derived suppressor cell (MDSC) in AP. We evaluated MDSC frequency and disease severity by analyzing MDSCs in the peripheral blood of healthy controls (HCs) and patients with mild acute pancreatitis (MAP) and SAP by flow cytometry. We also compared the frequency and inhibitory ability of MDSCs from HCs and SAP, and finally detected the reason for the difference in inhibitory ability. AP was marked by expansion of MDSCs as well as its subsets, granulocytic MDSCs (G-MDSCs) and monocytic MDSCs (M-MDSCs). The proportion of MDSC in the peripheral blood mononuclear cells of patients with AP was increased and positively correlated with AP severity. The frequency of MDSC was decreased after treatment compared with pre-treatment. CD3+ T cells were remarkably inhibited by MDSC derived from the patients with SAP. In the expression of arginase-1 (Arg-1) and reactive oxygen species (ROS), the MDSCs from patients with SAP increased. These findings demonstrated that MDSCs expanded in the peripheral blood in patients with AP, especially in those with SAP. Moreover, the inhibitory ability of MDSCs was increased in the patients with SAP compared with that in the HCs. The enhanced suppressive function was possibly caused by an overexpression of Arg-1 and ROS.

Schistosoma japonicum Cystatin Alleviates Sepsis Through Activating Regulatory Macrophages

Multi-organ failure caused by the inflammatory cytokine storm induced by severe infection is the major cause of death for sepsis. Sj-Cys is a cysteine protease inhibitor secreted by Schistosoma japonicum with strong immunomodulatory functions on host immune system. Our previous studies have shown that treatment with Sj-Cys recombinant protein (rSj-Cys) attenuated inflammation caused by sepsis. However, the immunological mechanism underlying the immunomodulation of Sj-Cys for regulating inflammatory diseases is not yet known. In this study, we investigated the effect of Sj-Cys on the macrophage M2 polarization and subsequent therapeutic effect on sepsis. The rSj-Cys was expressed in yeast Pichia pastoris. Incubation of mouse bone marrow-derived macrophages (BMDMs) with yeast-expressed rSj-Cys significantly activated the polarization of macrophages to M2 subtype characterized by the expression of F4/80⁺ CD206⁺ with the elated secretion of IL-10 and TGF-β. Adoptive transfer of rSj-Cys treated BMDMs to mice with sepsis induced by cecal ligation and puncture (CLP) significantly improved their survival rates and the systemic clinical manifestations of sepsis compared with mice receiving non-treated normal BMDMs. The therapeutic effect of Sj-Cys-induced M2 macrophages on sepsis was also reflected by the reduced pathological damages in organs of heart, lung, liver and kidney and reduced serological levels of tissue damage-related ALT, AST, BUN and Cr, associated with downregulated pro-inflammatory cytokines (IFN-gamma and IL-6) and upregulated regulatory anti-inflammatory cytokines (IL-10 and TGF-β). Our results demonstrated that Sj-Cys is a strong immunomodulatory protein with anti-inflammatory features through activating M2 macrophage polarization. The findings of this study suggested that Sj-Cys itself or Sj-Cys-induced M2 macrophages could be used as therapeutic agents in the treatment of sepsis or other inflammatory diseases.

The Role of Pancreatic Infiltrating Innate Immune Cells in Acute Pancreatitis

Acute pancreatitis (AP) is a leading cause of gastrointestinal-related hospital admissions with significant morbidity and mortality. Although the underlying pathophysiology of AP is rather complex, which greatly limits the treatment options, more and more studies have revealed that infiltrating immune cells play a critical role in the pathogenesis of AP and determine disease severity. Thus, immunomodulatory therapy targeting immune cells and related inflammatory mediators is expected to be a novel treatment modality for AP which may improve the prognosis of patients. Cells of the innate immune system, including macrophages, neutrophils, dendritic cells, and mast cells, represent the majority of infiltrating cells during AP. In this review, an overview of different populations of innate immune cells and their role during AP will be discussed, with a special focus on neutrophils and macrophages.

Macrophages in pancreatitis: Mechanisms and therapeutic potential

Macrophages play a crucial role in the pathogenesis of pancreatitis that is a common gastrointestinal disease. Particularly, macrophages differentiate into different phenotypes and exert diverse functions in acute pancreatitis (AP) and chronic pancreatitis (CP), respectively. In AP, macrophages in the pancreas and other related organs are mainly activated and differentiated into a pro-inflammatory M1 phenotype, and furthermore secrete inflammatory cytokines and mediators, causing local inflammation of the pancreas, and even intractable systemic inflammatory response or multiple organ failure. In CP, macrophages often exhibit a M2 polarisation and interact with pancreatic stellate cells (PSCs) in an autocrine and paracrine cytokine-dependent manner to promote the progression of pancreatic fibrosis. As the severity of pancreatic fibrosis aggravates, the proportion of M2/M1 macrophage cytokines in the pancreas increases. The discovery of macrophages in the pathogenesis of pancreatitis has promoted the research of targeted drugs, which provides great potential for the effective treatment of pancreatitis. This paper provides an overview of the roles of various macrophages in the pathogenesis of pancreatitis and the current research status of pancreatitis immunotherapy targeting macrophages. The findings addressed in this review are of considerable significance for understanding the pivotal role of macrophages in pancreatitis.

Exosomes derived from regulatory T cells ameliorate acute myocardial infarction by promoting macrophage M2 polarization

Acute myocardial infarction (AMI) is a serious ischemic heart disease. Regulatory T cells (Tregs) participate in AMI. This article aims to investigate the mechanism of action of Tregs in AMI. We constructed AMI mouse model. Then, AMI mouse and mouse macrophages (RAW264.7) were treated with Tregs or Treg-derived exosomes. The cardiac function of mice was detected. Triphenyl-tetrazolium chloride and TdT-mediated dUTP nick-end labeling staining were performed to detect the myocardial infarct size or apoptosis. The proportions of macrophages were analyzed by flow cytometry. Enzyme linked immunosorbent assay and quantitative real-time PCR was performed to estimate the levels of cytokines and genes. We found that Tregs ameliorated cardiac function, reduced myocardial infarct size and inhibited apoptosis of myocardial cells in AMI mice. Moreover, Treg-derived exosomes reduced myocardial infarct size and repressed apoptosis of myocardial cells in AMI mice. Furthermore, Treg-derived exosomes suppressed the expression of M1 macrophage markers, and promoted the expression of M2 macrophage markers in myocardial tissues of AMI mice and RAW264.7 cells. In conclusion, our work demonstrates that exosomes derived from Tregs ameliorate AMI by promoting macrophage M2 polarization. Thus, Tregs may be an essential cell for AMI treatment.

Phenotypical and Functional Polymorphism of Liver Resident Macrophages

Liver diseases are one of the main causes of mortality. In this regard, the development of new ways of reparative processes stimulation is relevant. Macrophages play a leading role in the regulation of liver homeostasis in physiological conditions and in pathology. In this regard, the development of new liver treatment methods is impossible without taking into account this cell population. Resident macrophages of the liver, Kupffer cells, represent a unique cell population, first of all, due to their development. Most of the liver macrophages belong to the self-sustaining macrophage cell population, whose origin is not bone marrow. In addition, Kupffer cells are involved in such processes as regulation of hepatocyte proliferation and apoptosis, remodeling of the intercellular matrix, lipid metabolism, protective function, etc. Such a broad spectrum of liver macrophage functions indicates their high functional plasticity. The review summarizes recent data on the development, phenotypic and functional plasticity, and participation in the reparative processes of liver macrophages: resident macrophages (Kupffer cells) and bone marrow-derived macrophages.

MIP-1α induces inflammatory responses by upregulating chemokine receptor 1/chemokine receptor 5 and activating c-Jun N-terminal kinase and mitogen-activated protein kinase signaling pathways in acute pancreatitis

OBJECTIVE

We aimed to investigate the association of macrophage inflammatory protein (MIP)-1α (CCL3) expression with the severity of acute pancreatitis (AP).

METHODS

The patients with AP were selected and divided into mild AP (MAP), moderately severe AP (MSAP), and severe AP (SAP) groups according to the severity of AP. The pancreatic acinar cell line Ar42 j was treated with cerulein to induce in vitro cell AP model. The expression of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) and the activation of the c-Jun N-terminal kinase (JNK)/p38 mitogen-activated protein kinase (MAPK) signaling pathway in stimulated or transfected Ar42 j cells were detected.

RESULTS

We detected that the upregulation of MIP-1α was associated with the severity of AP. Patients with SAP showed the highest MIP-1α contents, followed by MSAP, and, lastly, MAP. In cerulein-stimulated Ar42 j cells, the upregulation of MIP-1α, CCR5, TNF-α, and IL-6 was time dependent. In addition, in human recombinant MIP-1α treated Ar42 j cells, the upregulation of TNF-α and IL-6 was MIP-1α-dose-dependent. In contrast, we detected the inhibition of TNF-α and IL-6 in MIP-1α small interfering RNA (siRNA)-treated cells. Also, the activation of the JNK/p38 MAPK signaling pathway was induced and inhibited by human recombinant MIP-1α and MIP-1α siRNA, respectively.

CONCLUSION

These results suggested that MIP-1α might be used as a biomarker for the prognosis of AP severity. The MIP-1α-induced inflammatory responses in AP were mediated by TNF-α and IL-6, which were associated with the activation of the JNK/p38 MAPK signaling pathway.

Abdominal paracentesis drainage ameliorates severe acute pancreatitis in rats by regulating the polarization of peritoneal macrophages

AIM

To investigate the role of peritoneal macrophage (PM) polarization in the therapeutic effect of abdominal paracentesis drainage (APD) on severe acute pancreatitis (SAP).

METHODS

SAP was induced by 5% Na-taurocholate retrograde injection in Sprague-Dawley rats. APD was performed by inserting a drainage tube with a vacuum ball into the lower right abdomen of the rats immediately after the induction of SAP. To verify the effect of APD on macrophages, PMs were isolated and cultured in an environment, with the peritoneal inflammatory environment simulated by the addition of peritoneal lavage in complete RPMI 1640 medium. Hematoxylin and eosin staining was performed. The levels of pancreatitis biomarkers amylase and lipase as well as the levels of inflammatory mediators in the blood and peritoneal lavage were determined. The polarization phenotypes of the PMs were identified by detecting the marker expression of M1/M2 macrophages via flow cytometry, qPCR and immunohistochemical staining. The protein expression in macrophages that had infiltrated the pancreas was determined by Western blot.

RESULTS

APD treatment significantly reduced the histopathological scores and levels of amylase, lipase, tumor necrosis factor-α and interleukin (IL)-1β, indicating that APD ameliorates the severity of SAP. Importantly, we found that APD treatment polarized PMs towards the M2 phenotype, as evidenced by the reduced number of M1 macrophages and the reduced levels of pro-inflammatory mediators, such as IL-1β and L-selectin, as well as the increased number of M2 macrophages and increased levels of anti-inflammatory mediators, such as IL-4 and IL-10. Furthermore, in an in vitro study wherein peritoneal lavage from the APD group was added to the cultured PMs to simulate the peritoneal inflammatory environment, PMs also exhibited a dominant M2 phenotype, resulting in a significantly lower level of inflammation. Finally, APD treatment increased the proportion of M2 macrophages and upregulated the expression of the anti-inflammatory protein Arg-1 in the pancreas of SAP model rats.

CONCLUSION

These findings suggest that APD treatment exerts anti-inflammatory effects by regulating the M2 polarization of PMs, providing novel insights into the mechanism underlying its therapeutic effect.

Down-regulated paxillin suppresses cell proliferation and invasion by inhibiting M2 macrophage polarization in colon cancer

The paxillin and M2 macrophage are all involved in cell proliferation and tumor progression, and this study aims to explore the interaction between them in colon cancer and the role of paxillin in cancer progression. Expression of mRNAs and proteins was determined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blot, separately. Endogenous expression of genes was modulated by recombinant plasmids and cell transfection. The levels of cytokines were determined by enzyme-linked immunosorbent assay (ELISA). The cell viability, invasion and migration were detected using the MTT assay, the transwell assay and the wound-healing cell migration assay, respectively. A nude mouse model for human colon cancer was constructed for tumor orthotopic expression. Paxillin was up-regulated in tumor-associated macrophages (TAMs). Paxillin was up-regulated in process of M2 macrophage polarization. M2 macrophage polarization was inhibited with paxillin suppressed. Down-regulated paxillin inhibited cell proliferation and invasion in colon cancer through suppressing M2 macrophage polarization. PI3k/Akt inhibitor repressed M2 macrophage polarization through down-regulating paxillin. PI3k/Akt inhibitor inhibited the function of the macrophage in promoting cell proliferation and invasion of colon cancer through down-regulating paxillin. Down-regulated paxillin in macrophages inhibited tumor growth of colon cancer. With the PI3K/AKT pathway inhibited, down-regulated paxillin suppressed colon cancer cell proliferation and invasion by inhibiting the M2 macrophage polarization, thereby restraining the tumor progression.

Circulating CD14+CD163+CD115+ M2 monocytes are associated with the severity of new onset severe acute pancreatitis in Chinese patients

BACKGROUND

Despite the role of monocytes in the pathogenesis of severe acute pancreatitis (SAP), it remains unclear how different subtypes of monocytes regulate and contribute to this pathogenesis.

METHODS

We examined the numbers of different subsets of monocytes by flow cytometry in 21 SAP, 15 mild acute pancreatitis (MAP) and 13 healthy controls (HC). The concentrations of plasma cytokines were assessed by cytometric bead array. Disease severity was evaluated based on the acute physiology and chronic health evaluation (APACHE) II score and plasma C-reactive proteins (CRP) levels.

RESULTS

Compared with the numbers in MAP patients and HC, we observed that the numbers of CD14⁺CD163^-, CD14⁺CD163^-MAC387⁺, CD14⁺CD163^-IL-12⁺ M1 monocytes, and CD115⁺, CD204⁺, IL-10⁺ M2 monocytes were significantly increased in SAP patients. In addition, these patients showed higher plasma levels of interleukin (IL)-12 and IL-10. Furthermore, the number of CD14⁺CD163^-, CD14⁺CD163^-MAC387⁺ M1 monocytes and the plasma IL-12 concentration showed a positive association with the CRP level, while the number of CD204⁺, IL-10⁺ M2 monocytes and the plasma IL-10 concentration showed a positive correlation with the APACHE II score. Importantly, the CD115⁺ M2 subset displayed a positive correlation with both the CRP level and APACHE II score, and treatment of SAP significantly reduced the number of this subset.

CONCLUSIONS

The CD14⁺CD163⁺CD115⁺ M2 monocyte count appears to be important factor in determining the severity and prognosis of SAP. Both the pro- and anti-inflammatory monocytes appear to participate in the pathogenesis of SAP.

Mesenchymal stem cells rescue acute hepatic failure by polarizing M2 macrophages

AIM

To investigate whether M1 or M2 polarization contributes to the therapeutic effects of mesenchymal stem cells (MSCs) in acute hepatic failure (AHF).

METHODS

MSCs were transfused into rats with AHF induced by D-galactosamine (DGalN). The therapeutic effects of MSCs were evaluated based on survival rate and hepatocyte proliferation and apoptosis. Hepatocyte regeneration capacity was evaluated by the expression of the hepatic progenitor surface marker epithelial cell adhesion molecule (EpCAM). Macrophage polarization was analyzed by M1 markers [CD68, tumor necrosis factor alpha (TNF-α), interferon-γ (IFN-γ), inducible nitric oxide synthase (INOS)] and M2 markers [CD163, interleukin (IL)-4, IL-10, arginase-1 (Arg-1)] in the survival and death groups after MSC transplantation.

RESULTS

The survival rate in the MSC-treated group was increased compared with the DPBS-treated control group (37.5% vs 10%). MSC treatment protected rats with AHF by reducing apoptotic hepatocytes and promoting hepatocyte regeneration. Immunohistochemical analysis showed that MSC treatment significantly increased the expression of EpCAM compared with the control groups (P < 0.001). Expression of EpCAM in the survival group was significantly up-regulated compared with the death group after MSC transplantation (P = 0.003). Transplantation of MSCs significantly improved the expression of CD163 and increased the gene expression of IL-10 and Arg-1 in the survival group. IL-4 concentrations were significantly increased compared to the death group after MSC transplantation (88.51 ± 24.51 pg/mL vs 34.61 ± 6.6 pg/mL, P < 0.001). In contrast, macrophages showed strong expression of CD68, TNF-α, and INOS in the death group. The concentration of IFN-γ was significantly increased compared to the survival group after MSC transplantation (542.11 ± 51.59 pg/mL vs 104.07 ± 42.80 pg/mL, P < 0.001).

CONCLUSION

M2 polarization contributes to the therapeutic effects of MSCs in AHF by altering levels of anti-inflammatory and pro-inflammatory factors.

集束化护理在重症急性胰腺患者胃肠功能恢复中的应用

重症急性胰腺炎(severe acute pancreatitis, SAP)是临床中常见的发病率高、并发症多、死亡率较高的疾病, 其死亡的主要原因是并发了不同程度的多器官功能障碍综合征(multiple organ dysfunction syndrome, MODS), 全身炎症反应综合征(systemic inflammatory response syndrome, SIRS)是导致MODS的重要基础, 而胃肠功能障碍又是激发SIRS的源头. 因此, 胃肠功能障碍在该病的发生发展过程中起重要作用, 早期胃肠功能恢复有助于疾病的恢复和并发症的预防. 集束化护理的运用, 可以使每一位患者在有限的时间内, 得到最有效的治疗, 这是集束化护理最突出的特点. 文章就集束化护理在SAP患者的胃肠功能恢复中的应用进行简要综述, 为临床工作提供循证参考.

Different phenotypes of monocytes in patients with new-onset mild acute pancreatitis

AIM

To evaluate the numbers of different subsets of monocytes and their associations with the values of clinical measures in mild acute pancreatitis (MAP) patients.

METHODS

The study included one group of 13 healthy controls and another group of 24 patients with new-onset MAP. The numbers of different subsets of monocytes were examined in these two groups of subjects by flow cytometry. The concentrations of plasma interleukin (IL)-10 and IL-12 were determined by cytometric bead array. The acute physiology and chronic health evaluation (APACHE) II scores of individual patients were evaluated, and the levels of plasma C-reactive protein (CRP) as well as the activities of amylase and lipase were measured.

RESULTS

In comparison with that in the controls, significantly increased numbers of CD14+CD163-, CD14+CD163-MAC387+ M1 monocytes, but significantly reduced numbers of CD14+CD163+IL-10+ M2 monocytes were detected in the MAP patients (P < 0.01 or P < 0.05). Furthermore, significantly higher levels of plasma IL-10 and IL-12 were observed in the MAP patients (P < 0.01 for all). More importantly, the levels of plasma CRP were positively correlated with the numbers of CD14+CD163- (R = 0.5009, P = 0.0127) and CD14+CD163-MAC387+ (R = 0.5079, P = 0.0113) M1 monocytes and CD14+CD163+CD115+ M2 monocytes (R = 0.4565, P = 0.0249) in the patients. The APACHE II scores correlated with the numbers of CD14+CD163+CD115+ (R = 0.4581, P = 0.0244) monocytes and the levels of plasma IL-10 (R = 0.4178, P = 0.0422) in the MAP patients. However, there was no significant association among other measures tested in this population.

CONCLUSION

Increased numbers of CD14+CD163- and CD14+ CD163-MAC387+ monocytes may contribute to the pathogenesis of MAP, and increased numbers of CD14+CD163+CD115+ monocytes may be a biomarker for evaluating the severity of MAP.

IRF5 regulates lung macrophages M2 polarization during severe acute pancreatitis in vitro

AIM

To investigate the role of interferon regulatory factor 5 (IRF5) in reversing polarization of lung macrophages during severe acute pancreatitis (SAP) in vitro.

METHODS

A mouse SAP model was established by intraperitoneal (ip) injections of 20 μg/kg body weight caerulein. Pathological changes in the lung were observed by hematoxylin and eosin staining. Lung macrophages were isolated from bronchoalveolar lavage fluid. The quantity and purity of lung macrophages were detected by fluorescence-activated cell sorting and evaluated by real-time polymerase chain reaction (RT-PCR). They were treated with IL-4/IRF5 specific siRNA (IRF5 siRNA) to reverse their polarization and were evaluated by detecting markers expression of M1/M2 using RT-PCR.

RESULTS

SAP associated acute lung injury (ALI) was induced successfully by ip injections of caerulein, which was confirmed by histopathology. Lung macrophages expressed high levels of IRF5 as M1 phenotype during the early acute pancreatitis stages. Reduction of IRF5 expression by IRF5 siRNA reversed the action of macrophages from M1 to M2 phenotype in vitro. The expressions of M1 markers, including IRF5 (S + IRF5 siRNA vs S + PBS, 0.013 ± 0.01 vs 0.054 ± 0.047, P < 0.01), TNF-α (S + IRF5 siRNA vs S + PBS, 0.0003 ± 0.0002 vs 0.019 ± 0.018, P < 0.001), iNOS (S + IRF5 siRNA vs S + PBS, 0.0003 ± 0.0002 vs 0.026 ± 0.018, P < 0.001) and IL-12 (S + IRF5 siRNA vs S + PBS, 0.000005 ± 0.00004 vs 0.024 ± 0.016, P < 0.001), were decreased. In contrast, the expressions of M2 markers, including IL-10 (S + IRF5 siRNA vs S + PBS, 0.060 ± 0.055 vs 0.0230 ± 0.018, P < 0.01) and Arg-1 (S + IRF5 siRNA vs S + PBS, 0.910 ± 0.788 vs 0.0036 ± 0.0025, P < 0.001), were increased. IRF5 siRNA could reverse the lung macrophage polarization more effectively than IL-4.

CONCLUSION

Treatment with IRF5 siRNA can reverse the pancreatitis-induced activation of lung macrophages from M1 phenotype to M2 phenotype in SAP associated with ALI.

Potential scenarios leading to ovarian cancer arising from endometriosis

OBJECTIVES

The aim of this review was to highlight recent advances in our understanding of the pathogenesis of malignant transformation of endometriosis.

METHODS

This study reviewed the English-language literature concerning basic science studies of the potential promotion of carcinogenesis.

RESULTS

Repeated episodes of hemorrhage occur in endometriosis at the onset of menstruation. Extracellular hemoglobin, heme, and iron derivatives in endometriosis cause DNA damage and mutations, which create increased cellular susceptibility to oxidant-mediated cell killing. Excess DNA damage and mutations are linked to cell death, but not carcinogenesis. In response to an oxidative and inflammatory microenvironment, endometriotic cells and macrophages secrete antioxidants that control excess oxidative stress in the surrounding environment. Exposure of endometriotic cells to a sublethal level of oxidative stress may lead to carcinogenesis. Macrophages also secrete immunosuppressive factors that lead to promotion of malignant transformation.

DISCUSSION

At least two potential scenarios could result in ovarian cancer arising from endometriosis. The first step: extracellular hemoglobin, heme, and iron cause cellular oxidative damage by promoting reactive oxygen species formation, which results in DNA damage and mutations (ovarian cancer initiation from endometriosis). The second step: cancer progression may be associated with persistent antioxidant production favoring a protumoral microenvironment.

Compensatory Regulatory Networks between CD8 T, B, and Myeloid Cells in Organ Transplantation Tolerance

In transplantation tolerance, numerous regulatory populations have the capacity to inhibit allograft rejection; however, their compensatory capacities have never been clearly evidenced. We have previously demonstrated that the tolerogenic effect mediated by CD8(+)CD45RC(low) regulatory T cells (Tregs) in a model of organ transplantation with CD40Ig could be abrogated by permanent depletion of CD8(+) cells that resulted in allograft rejection in half of the recipients. This result demonstrated that CD8(+) Tregs were essential, but also that half of the recipients still survived indefinitely. We also demonstrated that no other regulatory populations, besides CD8(+) Tregs, could induce and maintain allograft tolerance in CD40Ig-treated tolerant animals. In the current study, we analyzed the mechanisms that arose following CD8(+) Treg depletion and allowed establishment of networks of new regulatory cells to maintain allograft survival. We identified regulatory B cells (Bregs) and regulatory myeloid cells (RegMCs) as being responsible of the maintenance of the long-term allograft survival. We demonstrated that both regulatory cell subsets efficiently inhibited antidonor immune responses in adoptively transferred recipients. Although Bregs were induced, they were not essential for the maintenance of the graft as demonstrated in IgM-deficient recipients. In addition, we showed that RegMCs were the most suppressive and acted alone, whereas Bregs activity was associated with increased suppressive activity of other subsets in adoptively transferred recipients. Altogether, to our knowledge, we demonstrated in this study for the first time the emergence of both Bregs and RegMCs following Tregs depletion and highlighted the importance of regulatory cell networks and their synergistic potential in transplantation.

Guggulsterone attenuates cerulein-induced acute pancreatitis via inhibition of ERK and JNK activation

Guggulsterone (GS), a plant steroid and a compound found at high levels in Commiphora myrrha, exhibits anti-inflammatory, anti-cancer, and cholesterol-lowering effects. However, the potential of GS to ameliorate acute pancreatitis (AP) is unknown. The aim of this study was to evaluate the effects of GS on cerulein-induced AP. AP was induced by intraperitoneally injecting supramaximal concentrations of the stable cholecystokinin analog cerulein (50 μg/kg) hourly for 6 h. In the GS-treated group, GS was administered intraperitoneally (10, 25, or 50mg/kg) 1 h before the first cerulein injection. Mice were sacrificed 6 h after the final cerulein injection. Blood samples were collected to measure serum lipase levels and evaluate cytokine production. The pancreas and lung were rapidly removed for morphologic and histological examinations, flow cytometry analysis, myeloperoxidase (MPO) assay, and real-time reverse transcription-polymerase chain reaction analysis. Pre-treatment with GS attenuated cerulein-induced histological damage, reduced pancreas weight/body weight ratio, decreased serum lipase levels, inhibited infiltrations of macrophages and neutrophils, and suppressed cytokine production. Additionally, GS treatment suppressed the activation of extracellular signal-regulated protein kinase (ERK) and c-Jun N-terminal kinase (JNK) in the pancreas in cerulein-induced pancreatitis. In conclusion, our results suggest that GS attenuates AP via deactivation of ERK and JNK.