[Preliminary clinical application of novel magnetic navigation and ultrasound-guided percutaneous transhepatic cholangiography drainage through the right liver duct for malignant obstructive jaundice]

Objective: To analyze the clinical application value of a novel magnetic navigation ultrasound (MNU) combined with digital subtraction angiography (DSA) dual-guided percutaneous transhepatic biliary drainage (PTCD) through the right hepatic duct for the treatment of malignant obstructive jaundice. Methods: Randomized controlled trial. The clinical data of 64 patients with malignant obstructive jaundice requiring PTCD through the right hepatic duct at the Hepatobiliary Center of the First Affiliated Hospital of Nanjing Medical University (Jiangsu Province People's Hospital) from December 2018 to December 2021 were retrospectively analyzed. The MNU group (n=32) underwent puncture guided by a novel domestic MNU combined with DSA, and the control group (n=32) underwent puncture guided by traditional DSA. The operation time, number of punctures, X-ray dose after biliary stenting as shown by DSA, patients' tolerance of the operation, success rate of the operation, pre- and post-operative total bilirubin, and incidence of postoperative complications were compared between the two groups. Results: The operation time of the MNU group was significantly shorter than that of the control group [(17.8±7.3) vs. (31.6±9.9) min, t=-6.35,P=0.001]; the number of punctures in the MNU group was significantly lower [(1.7±0.6) vs. (6.3±3.9) times, t=-6.59, P=0.001]; and the X-ray dose after biliary stenting as shown by DSA in the MNU group was lower than that in the control group [(132±88) vs. (746±187) mGy, t=-16.81,P<0.001]; Five patients in the control group were unable to tolerate the operation, and two stopped the operation, however all patients in the MNU group could tolerate the operation, and all completed the operation, with a success rate of 100% (32/32) in the MNU group compared to 93.8%(30/32) in the control group; the common complications of PTCD were biliary bleeding and infection, and the incidence of biliary bleeding (25.0%, 8/32) and infection (18.8%, 6/32) in the MNU group was significantly lower than that in the control group, 53.1% (17/32) and 28.1% (9/32), respectively. Conclusion: Magnetic navigation ultrasound combined with DSA dual-guided PTCD through the right biliary system for the treatment of malignant obstructive jaundice is safe and feasible.

miRNA-1 promotes acute myeloid leukemia cell pathogenesis through metabolic regulation

Acute myeloid leukemia (AML) is a heterogeneous and deadly disease characterized by uncontrolled expansion of malignant blasts. Altered metabolism and dysregulated microRNA (miRNA) expression profiles are both characteristic of AML. However, there is a paucity of studies exploring how changes in the metabolic state of the leukemic cells regulate miRNA expression leading to altered cellular behavior. Here, we blocked pyruvate entry into mitochondria by deleting the Mitochondria Pyruvate Carrier (MPC1) gene in human AML cell lines, which decreased Oxidative Phosphorylation (OXPHOS). This metabolic shift also led to increased expression of miR-1 in the human AML cell lines tested. AML patient sample datasets showed that higher miR-1 expression correlates with reduced survival. Transcriptional and metabolic profiling of miR-1 overexpressing AML cells revealed that miR-1 increased OXPHOS, along with key metabolites that fuel the TCA cycle such as glutamine and fumaric acid. Inhibition of glutaminolysis decreased OXPHOS in miR-1 overexpressing MV4-11 cells, highlighting that miR-1 promotes OXPHOS through glutaminolysis. Finally, overexpression of miR-1 in AML cells exacerbated disease in a mouse xenograft model. Together, our work expands current knowledge within the field by uncovering novel connections between AML cell metabolism and miRNA expression that facilitates disease progression. Further, our work points to miR-1 as a potential new therapeutic target that may be used to disrupt AML cell metabolism and thus pathogenesis in the clinic.

MicroRNA-155 Plays Selective Cell-Intrinsic Roles in Brain-Infiltrating Immune Cell Populations during Neuroinflammation

The proinflammatory microRNA-155 (miR-155) is highly expressed in the serum and CNS lesions of patients with multiple sclerosis (MS). Global knockout (KO) of miR-155 in mice confers resistance to a mouse model of MS, experimental autoimmune encephalomyelitis (EAE), by reducing the encephalogenic potential of CNS-infiltrating Th17 T cells. However, cell-intrinsic roles for miR-155 during EAE have not been formally determined. In this study, we use single-cell RNA sequencing and cell-specific conditional miR-155 KOs to determine the importance of miR-155 expression in distinct immune cell populations. Time-course single-cell sequencing revealed reductions in T cells, macrophages, and dendritic cells (DCs) in global miR-155 KO mice compared with wild-type controls at day 21 after EAE induction. Deletion of miR-155 in T cells, driven by CD4 Cre, significantly reduced disease severity similar to global miR-155 KOs. CD11c Cre-mediated deletion of miR-155 in DCs also resulted in a modest yet significant reduction in the development of EAE, with both T cell- and DC-specific KOs showing a reduction in Th17 T cell infiltration into the CNS. Although miR-155 is highly expressed in infiltrating macrophages during EAE, deletion of miR-155 using LysM Cre did not impact disease severity. Taken together, these data show that although miR-155 is highly expressed in most infiltrating immune cells, miR-155 has distinct roles and requirements depending on the cell type, and we have demonstrated this using the gold standard conditional KO approach. This provides insights into which functionally relevant cell types should be targeted by the next generation of miRNA therapeutics.

[Application of pretrained model based on electronic medical record in recognition of acute respiratory infection]

Objective: To evaluate the recognition of acute respiratory infection (ARI) by a pretrained model based on electronic medical records (EMRs). Methods: 38 581 EMRs were obtained from Chongqing University Three Gorges Hospital in December 2021. Bidirectional encoder representation from transformers (BERT) pretrained model was used to identify ARI in EMRs. The results of medical professionals were considered as the gold standard to calculate the sensitivity, specificity, Kappa value, and area under the curve of the receiver operating characteristic (AUC). Results: There were 3 817 EMRs in the test set, with 1 200 ARIs. A total of 1 205 cases were determined as ARI by the model, with a sensitivity of 92.67% (1 112/1 200) and a specificity of 96.45% (2 524/2 617). The model identified ARI with similar accuracy in males and females (AUCs 0.95 and 0.94, respectively), and was more accurate in identifying ARI cases in those aged less than 18 than in adults 18-59 and adults 60 and older (AUCs 0.94, 0.89 and 0.94, respectively). The current model had a better identification of ARIs in outpatient patients than that in hospitalized patients, with AUCs of 0.74 and 0.95, respectively. Conclusion: The use of the BERT pretrained model based on EMRs has a good performance in the recognition of ARI cases, especially for the outpatients and juveniles. It shows a great potential to be applied to the monitoring of ARI cases in medical institutions.

CD11c+ myeloid cell exosomes reduce intestinal inflammation during colitis

Intercellular communication is critical for homeostasis in mammalian systems, including the gastrointestinal (GI) tract. Exosomes are nanoscale lipid extracellular vesicles that mediate communication between many cell types. Notably, the roles of immune cell exosomes in regulating GI homeostasis and inflammation are largely uncharacterized. By generating mouse strains deficient in cell-specific exosome production, we demonstrate deletion of the small GTPase Rab27A in CD11c+ cells exacerbated murine colitis, which was reversible through administration of DC-derived exosomes. Profiling RNAs within colon exosomes revealed a distinct subset of miRNAs carried by colon- and DC-derived exosomes. Among antiinflammatory exosomal miRNAs, miR-146a was transferred from gut immune cells to myeloid and T cells through a Rab27-dependent mechanism, targeting Traf6, IRAK-1, and NLRP3 in macrophages. Further, we have identified a potentially novel mode of exosome-mediated DC and macrophage crosstalk that is capable of skewing gut macrophages toward an antiinflammatory phenotype. Assessing clinical samples, RAB27A, select miRNAs, and RNA-binding proteins that load exosomal miRNAs were dysregulated in ulcerative colitis patient samples, consistent with our preclinical mouse model findings. Together, our work reveals an exosome-mediated regulatory mechanism underlying gut inflammation and paves the way for potential use of miRNA-containing exosomes as a novel therapeutic for inflammatory bowel disease.

miR-aculous new avenues for cancer immunotherapy

The rising toll of cancer globally necessitates ingenuity in early detection and therapy. In the last decade, the utilization of immune signatures and immune-based therapies has made significant progress in the clinic; however, clinical standards leave many current and future patients without options. Non-coding RNAs, specifically microRNAs, have been explored in pre-clinical contexts with tremendous success. MicroRNAs play indispensable roles in programming the interactions between immune and cancer cells, many of which are current or potential immunotherapy targets. MicroRNAs mechanistically control a network of target genes that can alter immune and cancer cell biology. These insights provide us with opportunities and tools that may complement and improve immunotherapies. In this review, we discuss immune and cancer cell-derived miRNAs that regulate cancer immunity and examine miRNAs as an integral part of cancer diagnosis, classification, and therapy.

[Efficacy and safety of neoadjuvant immunotherapy for hepatocellular carcinoma]

Objective: To study the surgical safety and efficacy of preoperative neoadjuvant therapy with immune checkpoint inhibitors combined with anti-angiogenic drugs in patients with China liver cancer staging(CNLC)-Ⅱb and Ⅲa resectable hepatocellular carcinoma. Methods: The data of 129 patients with Ⅱb and Ⅲa hepatocellular carcinoma who underwent surgery at the First Affiliated Hospital of Nanjing Medical University from January 2018 to December 2020 were analyzed. All patients were divided into two groups: the neoadjuvant therapy group(n=14,13 males and 1 female,aged (55.4±12.6)years(range:34 to 75 years)) received immune combined targeted therapy before surgery,immune checkpoint inhibitor camrelizumab was administered intravenously at a dose of 200 mg each time,every 2 weeks for 3 cycles,anti-angiogenesis drug apatinib was taken orally and continuously with a dose of 250 mg for 3 weeks and the conventional surgery group(n=115,103 males and 12 females,aged (55.8±12.0)years(range:21 to 83 years)) did not receive antitumor systemic therapy before surgery. There were 3 patients with CNLC-Ⅱb,11 with CNLC-Ⅲa in the neoadjuvant group;28 patients with CNLC-Ⅱb,87 with CNLC-Ⅲa in the conventional group. Student's t test or rank-sum test was used to compare the differences between two groups for quantitative data, Fisher's exact probability method was used to compare the differences of proportions between two groups, and Log-rank test was used to compare survival differences between two groups. Results: The 1-year recurrence rate in the neoadjuvant group was 42.9%,and the 1-year recurrence rate in the conventional group was 64.0%,with a statistically significant difference between the two groups(χ²=3.850,P=0.050);The 1-year survival rate in the neoadjuvant group was 100% and that in the conventional group was 74.2%,with a statistically significant difference between the two groups(χ²=5.170,P=0.023). According to the stratified analysis of the number of tumors,for single tumor,the 1-year recurrence rate in the neoadjuvant group was 25.0%,and that in the conventional surgery group was 71.0%,and the difference between the two groups was statistically significant(χ²=5.280, P=0.022). For multiple tumors, the 1-year recurrence rate in the neoadjuvant group was 66.7%,and the 1-year recurrence rate in the conventional surgery group was 58.9%,with no significant difference between the two groups(χ²=0.110,P=0.736). The operative time,intraoperative blood loss,and postoperative hospital stay in the neoadjuvant group were similar to those in the conventional group,and their differences were not statistically significant. Conclusions: Immune checkpoint inhibitors combined with anti-angiogenic targeted drugs as a neoadjuvant therapy for resectable hepatocellular carcinoma can reduce the 1-year recurrence rate and improve the 1-year survival rate,especially for those with solitary tumor. Limited by the sample size of the neoadjuvant group,the safety of immune combined targeted therapy before surgery cannot be observed more comprehensively,and further studies will be explored.

Epithelial-myeloid exchange of MHC class II constrains immunity and microbiota composition

Intestinal epithelial cells (IECs) have long been understood to express high levels of major histocompatibility complex class II (MHC class II) molecules but are not considered canonical antigen-presenting cells, and the impact of IEC-MHC class II signaling on gut homeostasis remains enigmatic. As IECs serve as the primary barrier between underlying host immune cells, we reasoned that IEC-intrinsic antigen presentation may play a role in responses toward the microbiota. Mice with an IEC-intrinsic deletion of MHC class II (IECΔMHC class II) are healthy but have fewer microbial-bound IgA, regulatory T cells (Tregs), and immune repertoire selection. This was associated with increased interindividual microbiota variation and altered proportions of two taxa in the ileum where MHC class II on IECs is highest. Intestinal mononuclear phagocytes (MNPs) have similar MHC class II transcription but less surface MHC class II and are capable of acquiring MHC class II from IECs. Thus, epithelial-myeloid interactions mediate development of adaptive responses to microbial antigens within the gastrointestinal tract.

A Stat1 bound enhancer promotes Nampt expression and function within tumor associated macrophages

Tumor associated macrophage responses are regulated by distinct metabolic states that affect their function. However, the ability of specific signals in the local tumor microenvironment to program macrophage metabolism remains under investigation. Here, we identify NAMPT, the rate limiting enzyme in NAD salvage synthesis, as a target of STAT1 during cellular activation by interferon gamma, an important driver of macrophage polarization and antitumor responses. We demonstrate that STAT1 occupies a conserved element within the first intron of Nampt, termed Nampt-Regulatory Element-1 (NRE1). Through disruption of NRE1 or pharmacological inhibition, a subset of M1 genes is sensitive to NAMPT activity through its impact on glycolytic processes. scRNAseq is used to profile in vivo responses by NRE1-deficient, tumor-associated leukocytes in melanoma tumors through the creation of a unique mouse strain. Reduced Nampt and inflammatory gene expression are present in specific myeloid and APC populations; moreover, targeted ablation of NRE1 in macrophage lineages results in greater tumor burden. Finally, elevated NAMPT expression correlates with IFNγ responses and melanoma patient survival. This study identifies IFN and STAT1-inducible Nampt as an important factor that shapes the metabolic program and function of tumor associated macrophages.

Mitochondrial Pyruvate Carrier 1 Promotes Peripheral T Cell Homeostasis through Metabolic Regulation of Thymic Development

Metabolic pathways regulate T cell development and function, but many remain understudied. Recently, the mitochondrial pyruvate carrier (MPC) was identified as the transporter that mediates pyruvate entry into mitochondria, promoting pyruvate oxidation. Here we find that deleting Mpc1, an obligate MPC subunit, in the hematopoietic system results in a specific reduction in peripheral αβ T cell numbers. MPC1-deficient T cells have defective thymic development at the β-selection, intermediate single positive (ISP)-to-double-positive (DP), and positive selection steps. We find that early thymocytes deficient in MPC1 display alterations to multiple pathways involved in T cell development. This results in preferred escape of more activated T cells. Finally, mice with hematopoietic deletion of Mpc1 are more susceptible to experimental autoimmune encephalomyelitis. Altogether, our study demonstrates that pyruvate oxidation by T cell precursors is necessary for optimal αβ T cell development and that its deficiency results in reduced but activated peripheral T cell populations.

Maternally Acquired Zika Antibodies Enhance Dengue Disease Severity in Mice

Antibody (Ab)-dependent enhancement can exacerbate dengue virus (DENV) infection due to cross-reactive Abs from an initial DENV infection, facilitating replication of a second DENV. Zika virus (ZIKV) emerged in DENV-endemic areas, raising questions about whether existing immunity could affect these related flaviviruses. We show that mice born with circulating maternal Abs against ZIKV develop severe disease upon DENV infection. Compared with pups of naive mothers, those born to ZIKV-immune mice lacking type I interferon receptor in myeloid cells (LysMCre⁺Ifnar1^fl/fl) exhibit heightened disease and viremia upon DENV infection. Passive transfer of IgG isolated from mice born to ZIKV-immune mothers resulted in increased viremia in naive recipient mice. Treatment with Abs blocking inflammatory cytokine tumor necrosis factor linked to DENV disease or Abs blocking DENV entry improved survival of DENV-infected mice born to ZIKV-immune mothers. Thus, the maternal Ab response to ZIKV infection or vaccination might predispose to severe dengue disease in infants.

CD4+ T cells Promote Humoral Immunity and Viral Control during Zika Virus Infection

Several Zika virus (ZIKV) vaccines designed to elicit protective antibody (Ab) responses are currently under rapid development, but the underlying mechanisms that control the magnitude and quality of the Ab response remain unclear. Here, we investigated the CD4+ T cell response to primary intravenous and intravaginal infection with ZIKV. Using the LysMCre+Ifnar1fl/fl (myeloid type I IFN receptor-deficient) C57BL/6 mouse models, we identified six I-Ab-restricted ZIKV epitopes that stimulated CD4+ T cells with a predominantly cytotoxic Th1 phenotype in mice primed with ZIKV. Intravenous and intravaginal infection with ZIKV effectively induced follicular helper and regulatory CD4+ T cells. Treatment of mice with a CD4+ T cell-depleting Ab reduced the plasma cell, germinal center B cell, and IgG responses to ZIKV without affecting the CD8+ T cell response. CD4+ T cells were required to protect mice from a lethal dose of ZIKV after infection intravaginally, but not intravenously. However, adoptive transfer and peptide immunization experiments showed a role for memory CD4+ T cells in ZIKV clearance in mice challenged intravenously. These results demonstrate that CD4+ T cells are required mainly for the generation of a ZIKV-specific humoral response but not for an efficient CD8+ T cell response. Thus, CD4+ T cells could be important mediators of protection against ZIKV, depending on the infection or vaccination context.

CD4+ T cells promote humoral immunity and viral control during Zika virus infection

Several Zika virus (ZIKV) vaccines designed to elicit protective antibody (Ab) responses are currently under rapid development, but the underlying mechanisms that control the magnitude and quality of the Ab response remain unclear. Here, we investigated the CD4+ T cell response to primary intravenous and intravaginal infection with ZIKV. Using the LysMCre+Ifnar1fl/fl (myeloid type I IFN receptor-deficient) C57BL/6 mouse models, we identified six I-Ab-restricted ZIKV epitopes that stimulated CD4+ T cells with a predominantly cytotoxic Th1 phenotype in mice primed with ZIKV. Intravenous and intravaginal infection with ZIKV effectively induced follicular helper and regulatory CD4+ T cells. Treatment of mice with a CD4+ T cell-depleting Ab reduced the plasma cell, germinal center B cell, and IgG responses to ZIKV without affecting the CD8+ T cell response. CD4+ T cells were required to protect mice from a lethal dose of ZIKV after infection intravaginally, but not intravenously. However, adoptive transfer and peptide immunization experiments showed a role for memory CD4+ T cells in ZIKV clearance in mice challenged intravenously. These results demonstrate that CD4+ T cells are required mainly for the generation of a ZIKV-specific humoral response but not for an efficient CD8+ T cell response. Thus, CD4+ T cells could be important mediators of protection against ZIKV, depending on the infection or vaccination context.

Antidepressant but Not Prophylactic Ketamine Administration Alters Calretinin and Calbindin Expression in the Ventral Hippocampus

Ketamine has been found to have rapid, long-lasting antidepressant effects in treatment-resistant (TR) patients with major depressive disorder (MDD). Recently, we have also shown that ketamine acts as a prophylactic to protect against the development of stress-induced depressive-like behavior in mice, indicating that a preventative treatment against mental illness using ketamine is possible. While there is significant investigation into ketamine’s antidepressant mechanism of action, little is known about ketamine’s underlying prophylactic mechanism. More specifically, whether ketamine’s prophylactic action is molecularly similar to or divergent from its antidepressant action is entirely unknown. Here, we sought to characterize immunohistochemical signatures of cell populations governing ketamine’s antidepressant and prophylactic effects. 129S6/SvEv mice were treated with saline (Sal) or ketamine (K) either before a social defeat (SD) stressor as a prophylactic, or after SD as an antidepressant, then subsequently assessed for depressive-like behavior. Post-fixed brains were processed for doublecortin (DCX), calretinin (CR) and calbindin (CB) expression. The number of DCX⁺ neurons in the dentate gyrus (DG) of the hippocampus (HPC) was not affected by prophylactic or antidepressant ketamine treatment, while the number of CR⁺ neurons in the ventral hilus increased with antidepressant ketamine under SD conditions. Moreover, antidepressant, but not prophylactic ketamine administration significantly altered CR and CB expression in the ventral HPC (vHPC). These data show that while antidepressant ketamine treatment mediates some of its effects via adult hippocampal markers, prophylactic ketamine administration does not, at least in 129S6/SvEv mice. These data suggest that long-lasting behavioral effects of prophylactic ketamine are independent of hippocampal DCX, CR and CB expression in stress-susceptible mice.

[Analysis on probability of premature death and cause eliminated life expectancy of major non-communicable diseases in Chongqing Municipality, 2016]

Objective: To analyze the premature death probability and cause-eliminated life expectancy of cardiovascular disease, cancer, chronic respiratory disease and diabetes in Chongqing residents in 2016 so as to provide recommendation for non-communicable diseases (NCDs) prevention and control in Chongqing. Methods: Death cases of Chongqing Municipality between January 1(st) and December 31(st), 2016 were reported through death case registry system of national center for disease prevention and control. Death cases were sorted by international classification of disease (ICD-10). Mortality rate, standardized mortality rate, constituent ratio, premature death probability, life expectancy, and cause-eliminated life expectancy of four major NCDs were analyzed. Results: A total of 218 004 death cases were reported in Chongqing, 2016, and the mortality rate was 731.73/100 000. Of them, a total of 179 637 death cases of the four major NCDs including cardiovascular disease, cancer, chronic respiratory disease and diabetes were reported, accounting for 82.40% of all death cases. The mortality rate and standardized mortality rate of four major NCDs was 602.95/100 000 and 455.82/100 000, respectively. The premature death probability of four major NCDs was 15.96%, and males (25.39%) had a higher premature death probability than females (10.78%). The premature death probability of cardiovascular disease, cancer, chronic respiratory disease, and diabetes were 6.01%, 8.32%, 2.05%, and 0.43%, respectively. Life expectancy would increase by 6.02, 3.19, 1.89, and 0.19 years, after eliminating cardiovascular disease, cancer, chronic respiratory disease and diabetes respectively. Conclusion: The premature death probability of major NCDs was high in Chongqing, and males had a higher premature death probability than females did. Intervention and health management of the population should be conducted according to different gender-based risk factors to reduce the premature death probability.

Antitumor immunity is defective in T cell-specific microRNA-155-deficient mice and is rescued by immune checkpoint blockade

MicroRNA-155 (miR-155) regulates antitumor immune responses. However, its specific functions within distinct immune cell types have not been delineated in conditional KO mouse models. In this study, we investigated the role of miR-155 specifically within T cells during the immune response to syngeneic tumors. We found that miR-155 expression within T cells is required to limit syngeneic tumor growth and promote IFNγ production by T cells within the tumor microenvironment. Consequently, we found that miR-155 expression by T cells is necessary for proper tumor-associated macrophage expression of IFNγ-inducible genes. We also found that immune checkpoint-blocking (ICB) antibodies against programmed cell death protein 1/programmed death ligand 1 (PD-1/PD-L1) and cytotoxic T lymphocyte-associated protein 4 (CTLA-4) restored antitumor immunity in miR-155 T cell-conditional KO mice. We noted that these ICB antibodies rescued the levels of IFNγ-expressing T cells, expression of multiple activation and effector genes expressed by tumor-infiltrating CD8⁺ and CD4⁺ T cells, and tumor-associated macrophage activation. Moreover, the ICB approach partially restored expression of several derepressed miR-155 targets in tumor-infiltrating, miR-155-deficient CD8⁺ T cells, suggesting that miR-155 and ICB regulate overlapping pathways to promote antitumor immunity. Taken together, our findings highlight the multifaceted role of miR-155 in T cells, in which it promotes antitumor immunity. These results suggest that the augmentation of miR-155 expression could be used to improve anticancer immunotherapies.

Investigation of CD8+ T Cell Immunity in Zika Virus Infection Using Mouse Models

CD8+ T cells may play a dual role in both protection against and pathogenesis of Flaviviruses, including Zika virus (ZIKV). However, virtually nothing is currently known about the role CD8+ T cells play during ZIKV infection in humans and animal models. The goal of our study is to investigate the role of CD8+ T cells during primary ZIKV infection in mice. Using LysMCre+IFNARfl/fl C57BL/6 (H-2b) mice that lack type I IFN receptor in a subset of myeloid cells, we characterized a new mouse model susceptible to infection with both East African lineage (MR766) and Asian lineage (FSS13025) ZIKV strains. A screening of 244 ZIKV epitopes predicted to bind H-2b class I molecules, defined a specific map of 26 and 15 peptides for MR766 and FSS13025 ZIKV strains, respectively. Intracellular cytokine staining confirmed the identity of these epitopes and demonstrated induction of polyfunctional ZIKV-specific CD8+ T cells. Furthermore, adoptive transfer of ZIKV-immune CD8+ T cells reduced viral burdens, whereas depletion of CD8+ T cells led to higher tissue burdens and mortality was increased in ZIKV-infected CD8−/− mice compared to Wild-type. These results demonstrate that CD8+ T cells are important mediators of protection during primary ZIKV infection and provide a H-2b mouse model for investigating ZIKV-specific CD8+ T cell responses. Based on these findings, studies are in progress towards defining the role of resident memory CD8+ T cells in protection against ZIKV infection using our recently developed mouse models of ZIKV systemic infection and sexual transmission.

Modified mRNA Vaccines Protect against Zika Virus Infection

The emergence of ZIKV infection has prompted a global effort to develop safe and effective vaccines. We engineered a lipid nanoparticle (LNP) encapsulated modified mRNA vaccine encoding wild-type or variant ZIKV structural genes and tested immunogenicity and protection in mice. Two doses of modified mRNA LNPs encoding prM-E genes that produced virus-like particles resulted in high neutralizing antibody titers (∼1/100,000) that protected against ZIKV infection and conferred sterilizing immunity. To offset a theoretical concern of ZIKV vaccines inducing antibodies that cross-react with the related dengue virus (DENV), we designed modified prM-E RNA encoding mutations destroying the conserved fusion-loop epitope in the E protein. This variant protected against ZIKV and diminished production of antibodies enhancing DENV infection in cells or mice. A modified mRNA vaccine can prevent ZIKV disease and be adapted to reduce the risk of sensitizing individuals to subsequent exposure to DENV, should this become a clinically relevant concern.

Cross-Presentation of Soluble and Cell-Associated Antigen by Murine Hepatocytes Is Enhanced by Collectrin Expression

Cross-presentation is a modular series of intracellular events dictating the internalization and subsequent MHC class I (MHC I) display of extracellular Ags. This process has been defined in dendritic cells and plays a fundamental role in the induction of CD8⁺ T cell immunity during viral, intracellular bacterial, and antitumor responses. Herein, acute viral infection of murine liver with adenovirus, a model for intrahepatic cross-presentation, confirms hepatocytes directly contribute to cross-presentation of Ags and priming the pool of naive CD8⁺ T cells within the liver microenvironment. Processing of soluble and cell-associated Ags into peptide displayed by MHC I is however defective in hepatocytes lacking collectrin, an intracellular chaperone protein that localizes within the endoplasmic reticulum-Golgi intermediate compartment. Loss of hepatic collectrin expression leads to the diminished cross-priming and expansion of cytolytic antiviral CD8⁺ T cells. This study demonstrates that collectrin positively regulates processing of engulfed Ags into MHC I:peptide complexes within hepatocytes. Collectrin-mediated cross-presentation supports intrahepatic adaptive antiviral immune responses and may lead to insights into the nature of how the liver acts as a primary site of CD8⁺ T cell activation.

Mapping and Role of the CD8+ T Cell Response During Primary Zika Virus Infection in Mice

CD8+ T cells may play a dual role in protection against and pathogenesis of flaviviruses, including Zika virus (ZIKV). We evaluated the CD8+ T cell response in ZIKV-infected LysMCre+IFNARfl/fl C57BL/6 (H-2b) mice lacking the type I interferon receptor in a subset of myeloid cells. In total, 26 and 15 CD8+ T cell-reactive peptides for ZIKV African (MR766) and Asian (FSS13025) lineage strains, respectively, were identified and validated. CD8+ T cells from infected mice were polyfunctional and mediated cytotoxicity. Adoptive transfer of ZIKV-immune CD8+ T cells reduced viral burdens, whereas their depletion led to higher tissue burdens, and CD8-/- mice displayed higher mortality with ZIKV infection. Collectively, these results demonstrate that CD8+ T cells protect against ZIKV infection. Further, this study provides a T cell competent mouse model for investigating ZIKV-specific T cell responses.

Protective Role of Cross-Reactive CD8 T Cells Against Dengue Virus Infection

Infection with one of the four dengue virus serotypes (DENV1-4) presumably leads to lifelong immunity against the infecting serotype but not against heterotypic reinfection, resulting in a greater risk of developing Dengue Hemorrhagic Fever/Dengue Shock Syndrome (DHF/DSS) during secondary infection. Both antibodies and T cell responses have been implicated in DHF/DSS pathogenesis. According to the T cell-based hypothesis termed “original antigenic sin,” secondary DENV infection is dominated by non-protective, cross-reactive T cells that elicit an aberrant immune response. The goal of our study was to compare the roles of serotype-specific and cross-reactive T cells in protection vs. pathogenesis during DENV infection in vivo. Specifically, we utilized IFN-α/βR^−/− HLA*B0702 transgenic mice in the context of peptide vaccination with relevant human CD8 T cell epitopes. IFN-α/βR^−/− HLA*B0702 transgenic mice were immunized with DENV serotype 2 (DENV2)-specific epitopes or variants found in any of the other three serotypes (DENV1, DENV3 or DENV4), followed by challenge with DENV. Although cross-reactive T cell responses were lower than responses elicited by serotype-specific T cells, immunization with either serotype-specific or variant peptide epitopes enhanced viral clearance, demonstrating that both serotype-specific and cross-reactive T cells can contribute to protection in vivo against DENV infection.

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Serotype-cross-reactive CD8 T cells elicit a polyfunctional immune response similar to the response elicited by serotype-specific CD8 T cells.

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Serotype cross-reactive CD8 T cells play a role in protection against DENV infection in a HLA-B*0702 Transgenic IFN-α/βR^−/− mouse model.

There are four major subtypes (serotypes) of the mosquito-borne Dengue virus. Infection with a first serotype is generally asymptomatic, but secondary infection with a different serotype is capable of causing severe disease. T cells previously exposed to a first serotype and which produce an immune response to a second serotype are said to be cross-reactive. Using a mouse model engineered with human T cell features, we characterized the cross-reactive T cell response to live dengue virus serotypes and viral protein fragments. Our results suggested cross-reactive T cells contribute to control of and protection against infection by a second dengue serotype, rather than leading to more severe disease.

Influence of antibodies and T cells on dengue disease outcome: insights from interferon receptor-deficient mouse models

Dengue virus (DENV) is a globally important mosquito-borne virus that causes a spectrum of diseases ranging from dengue fever (DF) to dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS), affecting 3.6 billion people in 128 countries [1,2(•)]. There is an urgent need for a drug or vaccine against DENV, yet none are presently available. In fact, results from recent Phase IIb and III trials of an attenuated tetrameric vaccine revealed that the vaccine provided limited protection against DENV serotype 2 in DENV-immune people, and no protection against any serotype in naïve individuals [3-5], highlighting the difficulties associated with dengue vaccine development. A challenge in the development of a DENV vaccine is that a vaccine must protect against all four DENV serotypes, which co-circulate in endemic areas. Further complicating DENV vaccine development is that the correlates of protection are not fully defined, mechanisms regulating the generation of protective antibody and T cell responses against all four DENV serotypes are as yet to be deciphered, and the adaptive immune response may actually contribute to severe disease. Recent studies using the only available animal model of DHF/DSS in mice lacking one or more components of the interferon (IFN) system have begun to provide crucial insights into the protective versus pathogenic nature of both antibody and T cell responses to DENV. Herein, we highlight key studies using the IFN receptor-deficient mouse models toward understanding the contribution of antibodies and T cells in impacting the outcome of DENV infection.

CD8+ T cells prevent antigen-induced antibody-dependent enhancement of dengue disease in mice

Dengue virus (DENV) causes pathologies ranging from the febrile illness dengue fever to the potentially lethal severe dengue disease. A major risk factor for developing severe dengue disease is the presence of subprotective DENV-reactive Abs from a previous infection (or from an immune mother), which can induce Ab-dependent enhancement of infection (ADE). However, infection in the presence of subprotective anti-DENV Abs does not always result in severe disease, suggesting that other factors influence disease severity. In this study we investigated how CD8(+) T cell responses influence the outcome of Ab-mediated severe dengue disease. Mice were primed with aluminum hydroxide-adjuvanted UV-inactivated DENV prior to challenge with DENV. Priming failed to induce robust CD8(+) T cell responses, and it induced nonneutralizing Ab responses that increased disease severity upon infection. Transfer of exogenous DENV-activated CD8(+) T cells into primed mice prior to infection prevented Ab-dependent enhancement and dramatically reduced viral load. Our results suggest that in the presence of subprotective anti-DENV Abs, efficient CD8(+) T cell responses reduce the risk of Ab-mediated severe dengue disease.

10 GHz pulses generated across a ~100 nm tuning range using a gain-shifted mode-locked SOA ring laser

Widely-tunable picosecond pulses have been generated from a harmonically mode-locked semiconductor optical amplifier (SOA) ring laser with a center wavelength spanning from 1491 to 1588 nm. An intra-cavity birefringence loop mirror filter is used to define a 1.6 nm comb that governs the wavelength spacing of the tunable output pulses. The filter also serves to control the spectral gain profile of the laser cavity and thus extends the tuning range. By exploiting the spectral shift of the SOA gain with different amount of optical feedback, the output can be obtained over a wid wavelength range. Applying mode-locking together with the dispersion tuning approach, 10 GHz picosecond pulses have been successfully generated over a tuning range of 97 nm.

Repetition rate multiplication of multi-wavelength pulses by spectral elimination with a birefringence loop mirror filter

We demonstrate simultaneous repetition rate multiplication of laser pulses at multiple wavelengths using the spectral elimination approach. The phase coherence between the pulses is preserved while the aggregate bandwidth can be significantly enhanced. The repetition rates of pulses from both a mode-locked fiber ring laser and a pair of gain-switched DFB laser diodes have been multiplied to over 18 GHz per wavelength using the same setup. The key element is an all-fiber, polarization independent birefringence loop mirror comb filter. The broad transmission peaks of the filter also allow a large tolerance in the drift of the input wavelengths and repetition rates. A detuning range of 1.2 GHz is observed, corresponding to 13% of the input frequency.

Self-starting picosecond optical pulse source using stimulated Brillouin scattering in an optical fiber

We demonstrate a regeneratively mode-locked optical pulse source at about 10 GHz using an optoelectronic oscillator constructed with an electro-absorption modulator integrated distributed feedback laser diode. The 10 GHz RF component is derived from the interaction between the pump wave and the backscattered, frequency-downshifted Stokes wave resulted from stimulated Brillouin scattering in an optical fiber. The component serves as a modulation source for the 1556 nm laser diode without the need for any electrical or optical RF filter to perform the frequency extraction. Dispersion-compensated fiber, dispersion-shifted fiber, and standard single-mode fiber have been used respectively to generate optical pulses at variable repetition rates.

Effects of Epoetin alfa on hemostasis in chronic renal failure

Epoetin alfa is the cornerstone of anemia therapy in patients with end-stage renal disease. In addition to stimulating erythropoiesis, Epoetin alfa has been demonstrated to affect hemostasis. Such effects may be important because patients with chronic renal failure have a bleeding diathesis that is multifactorial in origin. Therefore, a computer literature search on the relationship between Epoetin alfa therapy for anemia in patients with end-stage renal disease and platelets, coagulation, coagulation inhibitors, and fibrinolysis was performed. All articles and abstracts reporting original data in the English language on Epoetin alfa and its effect on hemostasis were reviewed. The literature suggests that the effects of Epoetin alfa on the coagulation cascade are of minimal clinical importance. However, Epoetin alfa transiently increases the number of circulating platelets and improves platelet function, and these effects are associated with a return of the bleeding time towards normal.

Pathophysiological role of T lymphocytes in renal ischemia-reperfusion injury in mice

Mononuclear cell infiltrates are found in human renal ischemia-reperfusion injury (IRI), and peritubular T lymphocytes have been identified in experimental IRI. However, the role of T cells in the pathogenesis of renal IRI is unknown. We hypothesized that T cells are one of the important mediators of renal IRI. To test this hypothesis, we used an established mouse model of renal IRI, and evaluated mice with genetically engineered deficiency of both CD4+ and CD8+ T cells. At 48 h postischemia, CD4/CD8-knockout (KO) mice had marked improvement in renal function compared with control C57BL/6 mice (serum creatinine: 0.7 +/- 0.4 vs. 2.5 +/- 0.3 mg/dl, respectively; P < 0.05). Neutrophil infiltration into postischemic kidney was reduced in CD4/CD8 KO mice, compared with control mice, at both 24 h [polymorphonuclear neutrophils (PMNs)/10 high power fields: 714 +/- 354 vs. 3,514 +/- 660, respectively; P < 0.05] and 48 h (88 +/- 32 vs. 1,979 +/- 209, respectively; P < 0.05). Tubular necrosis score in CD4/CD8 KO mice, compared with control mice, was significantly less at 48 h (0.4 +/- 0.1 vs. 2.4 +/- 0.2, respectively; P < 0.05). Because adhesion between T cells and renal tubular epithelial cells (RTECs) may underlie the pathophysiological role of T cells in renal IRI, we also measured T cell adhesion to primary murine RTECs in vitro. Exposure of RTECs to 2 h of hypoxia followed by 1 h of reoxygenation increased T cell adhesion more than twofold. Phorbol ester treatment, which activates integrins, increased T cell adhesion threefold. These data suggest that T lymphocytes can mediate experimental renal IRI. Moreover, adhesion of infiltrating T cells to renal tubular cells may provide a potential mechanism underlying postischemic tubular dysfunction.

Glomerular extracellular matrix accumulation in experimental anti-GBM Ab glomerulonephritis

Thickening of the glomerular basement membrane (GBM) results from excessive accumulation of extracellular matrix (ECM) proteins following glomerular injury. We studied the temporal relationship between the expression of growth factors, ECM accumulation, ECM degrading proteinases, and their inhibitors in a rat model of anti-GBM antibody (Ab) glomerulonephritis (GN) by the RNase protection assay and immunohistochemistry. There were two- or fourfold increases in the expression of transforming growth factor-beta(1) (TGF-beta(1)) and platelet-derived growth factor (PDGF) A and B chain mRNAs 4 days after anti-GBM Ab administration. These changes were temporally associated with increased accumulation of alpha1(III) and alpha2(IV) collagens, fibronectin, and heparan sulfate proteoglycan along the GBM. The increase in matrix accumulation was associated with little or no increases in the proteinases, urokinase plasminogen activator (u-PA) and transin, respectively. There was a 1.6x increase in the u-PA/28s mRNA ratio on day 4 in rats with anti-GBM Ab GN, but this was not associated with an increase in u-PA biologic activity. By comparison, the mRNAs of the proteinase inhibitors, plasminogen activator inhibitor-1 (PAI-1) and tissue inhibitor of metalloproteinase (TIMP) were 5x greater than that of control rats on day 4. PAI-1 mRNA correlate with increased biologic activity. These data demonstrate a temporal association between TGF-beta(1) and PDGF expression and matrix accumulation within the GBM in anti-GBM Ab GN. In addition, it suggest that this matrix accumulation results from an imbalance between matrix synthesis and degradation.

Retinoic acid induces down-regulation of Wnt-3a, apoptosis and diversion of tail bud cells to a neural fate in the mouse embryo

The tail bud comprises the caudal extremity of the vertebrate embryo, containing a pool of pluripotent mesenchymal stem cells that gives rise to almost all the tissues of the sacro-caudal region. Treatment of pregnant mice with 100 mg/kg all-trans retinoic acid at 9.5 days post coitum induces severe truncation of the body axis, providing a model system for studying the mechanisms underlying development of caudal agenesis. In the present study, we find that retinoic acid treatment causes extensive apoptosis of tail bud cells 24 h after treatment. Once the apoptotic cells have been removed, the remaining mesenchymal cells differentiate into an extensive network of ectopic tubules, radially arranged around the notochord. These tubules express Pax-3 and Pax-6 in a regionally-restricted pattern that closely resembles expression in the definitive neural tube. Neurofilament-positive neurons subsequently grow out from the ectopic tubules. Thus, the tail bud cells remaining after retinoic acid-induced apoptosis appear to adopt a neural fate. Wnt-3a, a gene that has been shown to be essential for tail bud formation, is specifically down-regulated in the tail bud of retinoic acid-treated embryos, as early as 2 h after retinoic acid treatment and Wnt-3a transcripts become undetectable by 10 h. In contrast, Wnt-5a and RAR-gamma are still detectable in the tail bud at that time. Extensive cell death also occurs in the tail bud of embryos homozygous for the vestigial tail mutation, in which there is a marked reduction in Wnt-3a expression. These embryos go on to develop multiple neural tubes in their truncated caudal region. These results suggest that retinoic acid induces down-regulation of Wnt-3a which may play an important role in the pathogenesis of axial truncation, involving induction of widespread apoptosis, followed by an alteration of tail bud cell fate to form multiple ectopic neural tubes.

Crescentic glomerulonephritis in CD4- and CD8-deficient mice. Requirement for CD4 but not CD8 cells

The contribution of CD4 and CD8 cells to crescentic glomerulonephritis (GN) was studied in mice genetically deficient in CD4, CD8, and with combined CD4 and CD8 (CD4/CD8) deficiency. Wild-type (C57BL/6) mice developed GN with mild proliferative changes 7 days after an intravenous dose of sheep anti-mouse glomerular basement membrane globulin. Crescents were observed in 12.5 +/- 6.1% of glomeruli on day 14. On day 21, 51.5 +/- 7.3% of glomeruli were affected by crescents, and mice had marked azotemia and proteinuria. CD4 and combined CD4/CD8-deficient mice developed minimal evidence of GN. On day 21, their glomeruli showed only mild proliferative changes and crescents, azotemia, and proteinuria were absent. In contrast, CD8-deficient mice developed severe crescentic GN with three of five mice dying on day 20 with ascites and edema. The two mice surviving to day 21 had severe azotemia. Crescent development was accelerated (day 14, 51.6 +/- 2.4% of glomeruli; day 20 or 21, 62.0 +/- 4.0% of glomeruli). These studies demonstrate that CD4 cells are crucial for the development of crescentic GN in mice and that genetic absence of CD8 cells accelerates disease. They support the hypothesis that crescent formation is a manifestation of CD4-dependent (and CD8-independent) delayed type hypersensitivity in the glomerulus.

Chemokine expression in experimental tubulointerstitial nephritis

Chemokines may be important in the pathogenesis of leukocyte infiltration in tubulointerstitial nephritis associated with glomerular disease. We studied the renal cortical expression of the C-C (macrophage inflammatory protein-1alpha (MIP-1alpha)), monocyte chemotactic protein-1 (MCP-1), and RANTES) and C-X-C (interferon-inducible protein-10 (IP-10), MIP-2, and cytokine-induced neutrophil chemoattractant (CINC)) chemokines 4, 6, 8, 10, 14, and 21 days after the induction of puromycin aminonucleoside (PAN) nephrosis. There was a 7- to 10-fold increase in the steady state mRNA expression of IP-10 and MCP-1 in the renal cortex of rats 6 to 8 days after the administration of PAN that declines thereafter reaching control values by day 21. The site of IP-10 and MCP-1 mRNA production was localized to intrinsic tubulointerstitial cells and not to infiltrating monocytes or macrophages. By comparison, there was a low basal expression of RANTES mRNA in the renal cortex of nephrotic rats that did not differ from those of control rats. In contrast, CINC, MIP-2, and MIP-1alpha mRNAs were not detected. Translation of MCP-1 mRNA into protein was confirmed with an ELISA. These changes in chemokine gene expression were associated with a tubulointerstitial T lymphocyte and macrophage infiltration beginning on day 6 that peaked on day 10. Administration of a neutralizing Ab to rat MCP-1 (n = 5) beginning on day 4 resulted in a 45% decline in tubulointerstitial macrophage infiltration from 8.4 +/- 1.3% to 4.6 +/- 0.4% (p &lt; 0.001) on day 6. These data provide evidence that MCP-1, and possibly IP-10, are important in the pathogenesis of monocyte/macrophage infiltration in the tubulointerstitial nephritis associated with PAN nephrosis.

Chemokine expression in experimental tubulointerstitial nephritis

Chemokines may be important in the pathogenesis of leukocyte infiltration in tubulointerstitial nephritis associated with glomerular disease. We studied the renal cortical expression of the C-C (macrophage inflammatory protein-1alpha (MIP-1alpha)), monocyte chemotactic protein-1 (MCP-1), and RANTES) and C-X-C (interferon-inducible protein-10 (IP-10), MIP-2, and cytokine-induced neutrophil chemoattractant (CINC)) chemokines 4, 6, 8, 10, 14, and 21 days after the induction of puromycin aminonucleoside (PAN) nephrosis. There was a 7- to 10-fold increase in the steady state mRNA expression of IP-10 and MCP-1 in the renal cortex of rats 6 to 8 days after the administration of PAN that declines thereafter reaching control values by day 21. The site of IP-10 and MCP-1 mRNA production was localized to intrinsic tubulointerstitial cells and not to infiltrating monocytes or macrophages. By comparison, there was a low basal expression of RANTES mRNA in the renal cortex of nephrotic rats that did not differ from those of control rats. In contrast, CINC, MIP-2, and MIP-1alpha mRNAs were not detected. Translation of MCP-1 mRNA into protein was confirmed with an ELISA. These changes in chemokine gene expression were associated with a tubulointerstitial T lymphocyte and macrophage infiltration beginning on day 6 that peaked on day 10. Administration of a neutralizing Ab to rat MCP-1 (n = 5) beginning on day 4 resulted in a 45% decline in tubulointerstitial macrophage infiltration from 8.4 +/- 1.3% to 4.6 +/- 0.4% (p < 0.001) on day 6. These data provide evidence that MCP-1, and possibly IP-10, are important in the pathogenesis of monocyte/macrophage infiltration in the tubulointerstitial nephritis associated with PAN nephrosis.

Myofibroblast and alpha 1 (III) collagen expression in experimental tubulointerstitial nephritis

Despite the importance of tubulointerstitial fibrosis as a predictor of renal function in patients with primary glomerular disease, the identity of the cell(s) that is the source of interstitial collagen production remains unknown. The present study was performed to identify the site of alpha 1(III) production during the development of tubulointerstitial fibrosis. We studied a model of experimental tubulointerstitial nephritis associated with puromycin aminonucleoside (PAN) nephrosis. There was a twofold increase in renal cortical alpha 1 (III) mRNA expression coincident with the onset of tubulointerstitial myofibroblasts infiltration in rats with PAN nephrosis beginning on day 6, which increased to a fivefold difference by day 10. There were 60.8 +/- 40.3 myofibroblast/mm2 within the renal tubulointerstitium of rats with PAN nephrosis on day 6 that peaked at 240.2 +/- 11.1 myofibroblast/mm2 on day 14, which then declined to 43.7 +/- 9.8 myofibroblast/mm2 by day 21. By combining in situ hybridization with immunohistochemistry, alpha 1(III) mRNA expression was colocalized to cells that labeled for alpha-smooth muscle actin identifying them as myofibroblasts. Interestingly, the major site of alpha 1(III) mRNA expression shifted to tubuloepithelial cells with the waning of myofibroblast infiltration on day 21. To determine if PDGF-BB induced myofibroblasts to synthesize alpha 1(III) mRNA, we examined kidneys from rats that had been treated with PDGF-BB (5 mg/kg/day). alpha 1(III) mRNA expression also localized to cells that labeled for alpha-smooth muscle actin. These data demonstrate the cellular source of alpha 1(III) production within the renal tubulointerstitium following injury, and suggest that PDGF-BB may be mediating this production.

Leukemia inhibitory factor ameliorates experimental anti-GBM Ab glomerulonephritis

Leukemia inhibitory factor (LIF) is a pleiotropic cytokine that has been identified in acute and chronic inflammatory conditions such as rheumatoid arthritis, sepsis, and renal allograft rejection. We investigated the glomerular expression of LIF at 30 minutes, and 3, 6, 9, 15 and 24 hours after administration of anti-GBM Ab (N = 3) by the RNase protection assay. Control rats received rabbit sera and were sacrificed at 30 minutes, and 6 and 24 hours. LIF mRNA relative to GAPDH mRNA was detected at low levels within the glomeruli of occasional control rats. However with the induction of anti-GBM Ab GN, there was a marked increase in LIF steady-state mRNA beginning at three hours which persisted through 24 hour. LIF mRNA was also detected in cultured mesangial cells stimulated with IL-1 beta, identifying this cell type as a potential glomerular source for this cytokine. To investigate the in vivo effect of LIF, Lewis rats were continuously infused with recombinant (r) human (h) LIF (approximately 0.5 ng/hr) or saline vehicle i.p. with ALZA osmotic pumps beginning at t = -24 hours (N = 8). All rats were injected with anti-GBM Ab intravenously at t = 0 (N = 16). LIF infusion decreased 24-hour urinary protein excretion by 85% (17 +/- 15 vs. 114 +/- 37 mg/day, P = 0.0001) and was associated with a 60% decrease in glomerular macrophage infiltration (0.8 +/- 0.2 vs. 2.0 +/- 0.6 ED-1 cells/glom, P = 0.0001). The administration of rhLIF did not affect the binding of the anti-GBM Ab to glomeruli. The beneficial effects of LIF were associated with a decrease in glomerular MCP-1 (56%), IL-1 (41%) and TNF (17%) steady state mRNA expression. The latter was associated with a 29% decrease in TNF-alpha protein expression within the glomerular lysate of nephritic rats administered LIF when compared with control rats. These data demonstrate a potential role for LIF in the therapy of anti-GBM Ab GN.

Monocyte chemoattractant protein 1 mediates glomerular macrophage infiltration in anti-GBM Ab GN

Monocyte chemoattractant protein 1 (MCP-1) is a C-C chemokine with potent monocyte chemotactic and activating properties that may contribute to glomerular macrophage infiltration in anti-GBM Ab GN. We have previously reported increased glomerular steady state expression of MCP-1 mRNA relative to GAPDH mRNA in the heterologous phase of experimental anti-GBM Ab GN. In this report, we expand upon these data by demonstrating that the increase in MCP-1 mRNA correlated with MCP-1 protein expression at 24 hours that was determined with an ELISA (2069 +/- 147 pg/mg glom lysate). This increase in MCP-1 expression was associated with glomerular monocyte/ macrophage infiltration which peaked at 24 hours (8.2 +/- 1.0 ED-1 cells/glom). The site of MCP-1 mRNA production was localized by combining immunohistochemistry with in situ hybridization. The majority of cells which expressed MCP-1 mRNA at three hours were intrinsic glomerular cells, while 55% of the cells that expressed MCP-1 mRNA at 15 hours were monocytes/macrophages. To determine if MCP-1 affected glomerular macrophage infiltration, rats with alpha-GBM Ab GN were administered a polyclonal neutralizing Ab to rat MCP-1. This resulted in a 38% decline in glomerular macrophage infiltration (3.3 +/- 0.3 vs. 1.8 +/- 0.2 ED-1 cells/glom, P = 0.0001) that was associated with a 45% reduction in urinary protein excretion (260 +/- 53 vs. 162 +/- 46 mg/d, P = 0.0001). These data demonstrate an important role for MCP-1 in the pathogenesis of glomerular macrophage infiltration in anti-GBM Ab GN.

Platelet-derived growth factor-BB induces renal tubulointerstitial myofibroblast formation and tubulointerstitial fibrosis

Tubulointerstitial fibrosis correlates closely with renal function, although the mechanism regulating tubulointerstitial fibrogenesis remains poorly understood. Since platelet-derived growth factor (PDGF) is a growth factor for fibroblasts, we examined the effect of daily (for 7 days) PDGF-AA or PDGF-BB administration on renal tubulointerstitial architecture in rats. PDGF-AA administration at a dose of 5 mg/kg did not affect the renal tubulointerstitium. By comparison, PDGF-BB induced dose-dependent renal tubulointerstitial cell proliferation and fibrosis. At 5 mg/kg, PDGF-BB increased BrdU labeling in tubulointerstitial fibroblasts at 24 hours (19-fold), which peaked at 72 hours (23-fold) with bromodeoxyuridine uptake returning to control values by 7 days. Tubulointerstitial proliferation was associated with the differentiation of these cells into myofibroblasts as evidenced by alpha-smooth muscle actin expression beginning on day 3. The expression of alpha-smooth muscle actin peaked on day 5 and had markedly declined by day 21. In addition, apoptotic cells were identified within the tubulointerstitium on day 3 and progressively increased through day 7, suggesting that the disappearance of myofibroblasts may have occurred through apoptosis. These changes were accompanied by increased expression of alpha 1 (III) collagen mRNA and interstitial accumulation of type III collagen within the renal cortex. By morphometric analysis, an approximately twofold increase in collagen III immunolabeling within the interstitial compartment was evident at 24 hours and peaked on days 5 to 7 (approximately fourfold). These data suggest that PDGF-BB may be an important mediator of tubulointerstitial hyperplasia and fibrosis.

Intratracheal injection of endotoxin and cytokines. IX. Contribution of CD11a/ICAM-1 to neutrophil emigration

Intratracheal injection of endotoxin [lipopolysaccharide (LPS)] in rats causes acute inflammation characterized by the emigration of neutrophils (PMNs) into the bronchoalveolar airspace. Antibody to PMN adhesion molecule CD11a inhibited LPS-initiated PMN accumulation in bronchoalveolar lavage (BAL) fluid by 32% (P < 0.001). Antibody to the endothelial CD11a counterreceptor intercellular adhesion molecule-1 (ICAM-1) inhibited LPS-initiated PMN accumulation in BAL fluid by 66% (P < 0.0001). Combined antibody blockade of ICAM-1 and the C-X-C chemokine cytokine-induced neutrophil chemoattractant (CINC) inhibited LPS-initiated PMN emigration by 80%, significantly more than antibody against either ICAM-1 or CINC alone. To study the relative contribution of alveolar macrophages and PMNs to intra-alveolar tumor necrosis factor (TNF), the LPS-induced TNF in BAL fluid was measured after depletion of circulating PMNs with a cytolytic antibody to CD18. Although the anti-CD18 antibody completely abrogated LPS-initiated PMN emigration into BAL fluid, TNF levels in BAL fluid were unaffected, suggesting that alveolar macrophages are the predominant cellular source of LPS-induced TNF production. In conclusion, 1) CD11a, ICAM-1, and CINC play major roles in the LPS-initiated emigration of PMNs into the bronchoalveolar space, and 2) the TNF that drives ICAM-1 and CINC expression is derived largely from alveolar macrophages rather than PMNs.

Chemokine gene expression in anti-glomerular basement membrane antibody glomerulonephritis

Chemokines may be important in the pathogenesis of glomerular leukocyte infiltration in antiglomerular basement membrane (GBM) antibody (Ab) glomerulonephritis (GN). We studied the expression of the C-C chemokines [macrophage inflammatory protein (MIP)-1 alpha, monocyte chemotactic protein (MCP)-1, and RANTES] and C-X-C chemokines [platelet factor 4 (PF4), interferon-inducible protein of 10 kDa (IP-10), MIP-2, and cytokine-induced neutrophil chemoattractant (CINC)] at 30 min, 3, 6, 9, 15, and 24 h after induction of heterologous-phase anti-GBM Ab GN in Lewis rats. There was a rapid induction of CINC, MIP-2, MCP-1, and MIP-1 alpha mRNAs in the glomeruli of nephritic rats 30 min after administration of the anti-GBM Ab, whereas increases in PF4 and IP-10 mRNAs were not seen until 3 h. The mRNA expression of PF4, MIP-1 alpha, MIP-2, and IP-10 peaked at 3 h, whereas CINC and MCP-1 peaked at 6 and 15 h, respectively. By comparison, the expression of RANTES mRNA in rats with anti-GBM Ab GN did not differ from those of control rats. These changes in chemokine gene expression were associated with glomerular polymorphonuclear leukocytes (PMN) and monocyte/macrophage infiltration which peaked at 3 h (20.8 +/- 11.1 PMN/glomerulus) and 24 h (8.2 +/- 1.0 ED-1 cells/glomerulus), respectively. The administration of dexamethasone suppressed glomerular chemokine mRNA expression (60-98%) at both 3 and 15 h, which was associated with a 50-100% reduction in glomerular PMN and monocyte/macrophage infiltration, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Protein C inhibitor is expressed in tubular cells of human kidney

Protein C inhibitor (PCI) is a serpin that inhibits a number of proteases. PCI is found in urine and binds to kidney epithelial cells. To determine if kidney is a source of PCI, cDNA was produced from human kidney total RNA. Sequencing and restriction mapping showed identity between kidney and liver PCI cDNA sequences. Similar cDNAs were obtained from rhesus monkey kidney and liver RNAs. Conditioned medium from the rhesus monkey kidney cell line CCL7.1 was analyzed on immunoblots, showing a 57,000-D protein band that comigrated with human plasma PCI. Immunohistochemical staining and in situ hybridization of human kidney tissue sections showed that kidney PCI antigen and RNA were confined to tubular cells. The findings are consistent with the idea that PCI is synthesized and localized in kidney tissue where it may provide protease inhibitory activity and suggest that complexes of PCI with urokinase found in human urine may be produced locally in the kidney.

Cytokine expression, upregulation of intercellular adhesion molecule-1, and leukocyte infiltration in experimental tubulointerstitial nephritis

BACKGROUND

Cytokines are intercellular polypeptide messengers that mediate immune and inflammatory responses. The temporal profile of interleukin-1 beta (IL-1 beta), IL-6, tumor necrosis factor alpha (TNF-alpha), and monocyte chemotactic protein 1 (MCP-1) expression was examined in anti-tubular basement membrane (TBM) antibody-associated tubulointerstitial nephritis (TIN).

EXPERIMENTAL DESIGN

TIN was induced by immunization of Brown Norway rats with bovine cortical TBM, whereas control rats received ovalbumin. Whole kidney RNA was assessed with the RNase protection assay 3, 7, 8, 9, 10, 12, and 14 days after immunization. Cytokine mRNA expression was correlated with TNF-alpha bioactivity, renal intercellular adhesion molecule-1 expression, and CD18-positive leukocyte infiltration by immunohistochemistry.

RESULTS

Increased IL-1 beta, TNF-alpha, and MCP-1 mRNA relative to glyceraldehyde-3-phosphate dehydrogenase appeared on day 7 when TIN involved 10 to 40% of the cortex, and peaked rapidly on day 8 when there was 60 to 80% cortical involvement (at which time 75 to 80% of the infiltrating cells were neutrophils). The increase in TNF-alpha mRNA correlated with increased bioactivity. The influx of mononuclear cells on day 8 was preceded by the expression of MCP-1 mRNA. The infiltrating leukocytes expressed the leukocyte beta 2-integrin (CD18) and were found in areas with increased intercellular adhesion molecule-1 expression. The mRNAs for IL-1 beta, TNF-alpha, and MCP-1 were undetectable by day 10 (at which time 95% of the infiltrating cells were mononuclear). An increase in IL-1 receptor antagonist mRNA paralleled those of IL-1 beta. The expression of IL-6 mRNA was similar to that for IL-1, except that it disappeared by day 9.

CONCLUSIONS

There is a temporal association in the expression of IL-1 beta, TNF alpha, MCP-1, and IL-6 with the upregulation of intercellular adhesion molecule-1 and leukocyte infiltration within the tubulointerstitium in anti-TBM antibody-associated TIN. The narrow window of time through which these cytokines are expressed and the coincidence of their peak expression on day 8 suggest complex cytokine interactions in the pathogenesis of anti-TBM antibody TIN.

Extracellular matrix accumulation in immune-mediated tubulointerstitial injury

The accumulation of excessive extracellular matrix (ECM) following tubular injury likely represents an imbalance between ECM production and degradation. We assessed the temporal relationship between the accumulation of ECM, cell adhesion molecules, matrix degrading proteinases, and their inhibitors in a rat model of anti-tubular basement membrane (TBM) antibody-associated tubulointerstitial nephritis (TIN) by the RNase protection assay and immunohistochemistry. There was an increase in the steady state expression of fibronectin (FN) and alpha 2(IV) collagen mRNAs beginning on day 7 with the onset of neutrophil infiltration. An increase in alpha 1(III) collagen and alpha 1-integrin did not occur until days 9 and 10, respectively, at which time mononuclear leukocytes were the predominant infiltrating cell. Increased levels of FN, alpha 1(III), alpha 2(IV) and alpha 1-integrin mRNAs occurred through day 14. By immunohistochemistry, increased accumulation of collagen IV, heparan sulfate proteoglycan, and laminin were detected along the thicken TBM; collagens I and III were immunolocalized within the tubulo-interstitium, while FN was present in both the TBM and interstitium in rats with TIN on day 14. The increase in matrix accumulation was associated with little or no increase in proteinases. u-PA transcripts fell beginning on day 8, with recovery to control values by day 12. Transin mRNA was found at low levels only on days 8 and 9, and the protein could not be detected by Western blotting. In contrast, these changes were associated with an increase in proteinase inhibitors, so that TIMP and PAI-1 mRNAs increased beginning on day 7 and persisted through day 14.(ABSTRACT TRUNCATED AT 250 WORDS)

Interleukin-1 receptor antagonist ameliorates experimental anti-glomerular basement membrane antibody-associated glomerulonephritis

The contribution of IL-1 to leukocyte infiltration in anti-glomerular basement membrane (GBM) antibody (Ab) glomerulonephritis (GN) was examined by the administration of a specific IL-1 receptor antagonist (IL-1ra). Lewis rats received anti-GBM Ab or normal rabbit serum and were treated with either 0.9% saline or 6 mg IL-1ra over a 24-h time period. Plasma IL-1ra concentration was 2,659 +/- 51 ng/ml 4 h after anti-GBM Ab and IL-1ra administration. PMN and monocyte/macrophage infiltration declined 39% (9.8 +/- 1.9 to 6.0 +/- 1.5 PMN/glomerulus, P < 0.001) and 29% (4.9 +/- 0.8 to 3.5 +/- 0.8 ED-1 cells/glomerulus, P = 0.002) with IL-1ra treatment at 4 h, respectively. Similarly, the number of glomerular cells staining for lymphocyte function-associated molecule-1 beta (CD18) declined 39% from 16.7 +/- 1.9 to 10.7 +/- 1.6 cells/glomerulus at 4 h (P = 0.0001). This was associated with a decrease in glomerular intracellular adhesion molecule-1 expression. The mean glomerular intracellular adhesion molecule-1 score in anti-GBM Ab GN rats treated with IL-1ra was less than that of rats administered anti-GBM Ab and 0.9% saline at 4 (2.0 +/- 0.2 vs 2.5 +/- 0.2, P < 0.05) and 24 (2.5 +/- 0.1 vs 3.1 +/- 0.2, P = 0.0001) h. These immunopathologic changes correlated with a 50% reduction in proteinuria from 147 +/- 34 to 75 +/- 25 mg/d (P < 0.002). Treatment with IL-1ra did not affect the steady state mRNA expression of either IL-1 beta or TNF alpha. An increase in the IL-1ra dose to 30 mg given within the initial 4 h provided no additional benefit. The decline in PMN and monocyte/macrophage infiltration of the glomerulus at 4 h was similar to that found in the initial study. Furthermore, the protective benefit of IL-1ra was abrogated by doubling the dose of the anti-GBM Ab GN, despite administering high dose IL-1ra (30 mg). In these studies, detectable IL-1ra was found in the serum of untreated anti-GBM Ab GN controls. These data suggest a positive yet limited role for IL-1ra in the therapeutic intervention of anti-GBM Ab GN.

Cloning two isoforms of rat cyclooxygenase: differential regulation of their expression

Two isoforms of cyclooxygenase (COX) have been identified in eukaryotic cells: COX-1 encoded by a 2.8-kb mRNA, and a mitogen-inducible COX-2 encoded by a 4-kb mRNA. We have cloned the COX-1 and COX-2 cDNAs from the cDNA library constructed from lipopolysaccharide (LPS)-stimulated rat peritoneal macrophages. The deduced amino acid sequence showed that COX-1 contained 602 amino acids, whereas COX-2 contained 604 amino acids. There is 95% conservation of the nucleotide sequence in the open reading frame of COX-1 between the rat and the mouse, while the homology of the 3' untranslated region is 68% except for a 150 bp segment adjacent to the stop codon which is nonhomologous with the mouse. Transfection of both COX cDNAs into Cos-7 cells resulted in increased COX activity. In rat vascular smooth muscle cells, interleukin-1 beta selectively increased the expression of COX-2, but not that of COX-1, as assessed by enzyme activity, immunoprecipitation of COX proteins, and mRNA analysis. Only the brain among tissues tested exhibits basal expression of COX-2 as the major form of the enzyme. However, COX-2 mRNA was expressed in vivo in the lung and kidney, but not in the heart, after systemic administration of LPS, suggesting that COX-2 but not COX-1 plays a major role in producing COX-derived products of arachidonic acid during endotoxic shock. Thus, the two COX isoforms were differentially expressed, and COX-2 was selectively induced in response to inflammatory stimuli in rats.

Cloning a novel form of rat PDGF A-chain with a unique 5'-UT: regulation during development and in glomerulonephritis

An unique form of rat platelet-derived growth factor A-chain (PDGF A-chain), with a novel 5' UT region, was cloned from a rat macrophage cDNA library and expressed. In the 5' UT, the homology of the 79 bp sequence adjacent to the ATG codon between rat and human was 92%; however, the homology of the remainder in the 5' UT was less than 30%. RNase mapping indicated this form was differentially expressed during development and immune glomerular injury, and that it probably arose from alternative splicing. We propose that the variant mRNAs reflect different levels of the control of PDGF A-chain expression.