Maternal Innate Immune Reprogramming After Complicated Pregnancy.

PROBLEM: Preeclampsia (PE) and fetal growth restriction (FGR) are often associated with maternal inflammation and an increased risk of cardiovascular and metabolic disease in the affected mothers. The mechanism responsible for this increased risk of subsequent disease may involve reprogramming of innate immune cells, characterized by epigenetic modifications. METHOD OF STUDY: Circulating monocytes from women with PE, FGR, or uncomplicated pregnancies (control) were isolated before labor. Cytokine release from monocytes following exposure to lipopolysaccharide (LPS) and the presence of lysine 4-trimethylated histone 3 (H3K4me3) within TNF promoter sequences were evaluated. Single-cell transcriptomic profiles of circulating monocytes from women with PE or uncomplicated pregnancies were assessed. RESULTS: Monocytes from women with PE or FGR exhibited increased IL-10 secretion and decreased IL-1ß and GM-CSF secretion in response to LPS. While TNFα secretion was not significantly different in cultures of control monocytes versus those from complicated pregnancies with or without LPS exposure, monocytes from complicated pregnancies had significantly decreased levels of H3K4me3 associated with TNF promoter sequences. Cluster quantification and pathway analysis of differentially expressed genes revealed an increased proportion of anti-inflammatory myeloid cells and a lower proportion of inflammatory non-classical monocytes among the circulating monocyte population in women with PE. CONCLUSIONS: Monocytes from women with PE and FGR exhibit an immune tolerance phenotype before initiation of labor. Further investigation is required to determine whether this tolerogenic phenotype persists after the affected pregnancy and contributes to increased risk of subsequent disease.

Predictive biomarkers and initial analysis of maternal immune alterations in postpartum preeclampsia reveal an immune-driven pathology.

Introduction: Postpartum preeclampsia (PPPE) is an under-diagnosed condition, developing within 48 hours to 6 weeks following an uncomplicated pregnancy. The etiology of PPPE is still unknown, leaving patients vulnerable and making the identification and treatment of patients requiring postpartum care an unmet need. We aimed to understand the immune contribution to PPPE at the time of diagnosis, as well as uncover the predictive potential of perinatal biomarkers for the early postnatal identification of high-risk patients. Methods: Placentas were collected at delivery from uncomplicated pregnancies (CTL) and PPPE patients for immunohistochemistry analysis. In this initial study, blood samples in PPPE patients were collected at the time of PPPE diagnosis (48h-25 days postpartum; mean 7.4 days) and compared to CTL blood samples taken 24h after delivery. Single-cell transcriptomics, flow cytometry, intracellular cytokine staining, and the circulating levels of inflammatory mediators were evaluated in the blood. Results: Placental CD163+ cells and 1st trimester blood pressures can be valuable non-invasive and predictive biomarkers of PPPE with strong clinical application prospects. Furthermore, changes in immune cell populations, as well as cytokine production by CD14+, CD4+, and CD8+ cells, suggested a dampened response with an exhausted phenotype including decreased IL1ß, IL12, and IFNγ as well as elevated IL10. Discussion: Understanding maternal immune changes at the time of diagnosis and prenatally within the placenta in our sizable cohort will serve as groundwork for pre-clinical and clinical research, as well as guiding clinical practice for example in the development of immune-targeted therapies, and early postnatal identification of patients who would benefit from more thorough follow-ups and risk education in the weeks following an uncomplicated pregnancy.

Systemic versus localized Bacillus Calmette Guérin immunotherapy of bladder cancer promotes an anti-tumoral microenvironment: Novel role of trained immunity.

Treatment for higher-risk non-muscle invasive bladder cancer (NMIBC) involves intravesical immunotherapy with Bacillus Calmette Guérin (BCG); however, disease recurrence and progression occur frequently. Systemic immunity is critical for successful cancer immunotherapy; thus, recurrence of NMIBC may be due to suboptimal systemic activation of anti-tumor immunity after local immunotherapy. We previously reported that systemically acquired trained immunity (a form of innate immune memory) in circulating monocytes is associated with increased time-to-recurrence in patients with NMIBC treated with BCG. Herein, we used a mouse model of NMIBC to compare the effects of intravesical versus intravenous (systemic) BCG immunotherapy on the local and peripheral immune microenvironments. We also assessed whether BCG-induced trained immunity modulates anti-tumor immune responses. Compared with intravesical BCG, which led to a tumor-promoting immune microenvironment, intravenous BCG resulted in an anti-tumoral bladder microenvironment characterized by increased proportions of cytotoxic T lymphocytes (CTLs), and decreased proportions of myeloid-derived suppressor cells. Polarization toward anti-tumoral immunity occurred in draining lymph nodes, spleen, and bone marrow following intravenous versus intravesical BCG treatment. Pre-treatment with intravesical BCG was associated with increased rate of tumor growth compared with intravenous BCG pre-treatment. Trained immunity contributed to remodeling of the tumor immune microenvironment, as co-instillation of BCG-trained macrophages with ovalbumin-expressing bladder tumor cells increased the proportion of tumor-specific CTLs. Furthermore, BCG-trained dendritic cells exhibited enhanced antigen uptake and presentation and promoted CTL proliferation. Our data support the concept that systemic immune activation promotes anti-tumor responses, and that BCG-induced trained immunity is important in driving anti-tumor adaptive immunity.

Association of Histone H3 Trimethylation in Circulating Monocytes with Lack of Early Recurrence in Patients with Bladder Cancer following BCG Induction Therapy.

BACKGROUND: The mode of action of Bacillus Calmette-Guérin (BCG) in the treatment of patients with non-muscle invasive bladder cancer (NMIBC) is incompletely understood, but recent studies support an association between BCG-induced trained immunity in circulating monocytes and disease-free survival. OBJECTIVE: We compared epigenetic profiles in monocytes from NMIBC patients with early disease recurrence with those from recurrence-free patients. METHODS: We conducted chromatin immunoprecipitation and DNA sequencing (ChIP-seq) on monocytes from seven patients treated with BCG (four with early recurrences and three recurrence-free after one year) to determine genome-wide distribution and abundance of histone 3 lysine 4 trimethylation (H3K4me3) prior to and after five weeks of induction therapy. RESULTS: Genome-wide H3K4me3 profiles before or after BCG induction distinguished patients with early recurrences from those remaining recurrence-free. Furthermore, H3K4me3 levels at genes involved in specific pathways were increased in the recurrence-free group. Independent quantification showed increased H3K4me3 levels in elements of the Wnt and AMPK signaling pathways in the recurrence-free group before BCG initiation, while elements of the MAPK showed increased levels after five weeks of induction in the same group. Validation of these genes on an independent cohort of four additional patients that remained recurrence-free after one year and three with early recurrences revealed consistent increases in H3K4me3 levels associated with MAPK pathway genes after five weeks of BCG treatment in the recurrence-free group. CONCLUSIONS: Recurrence-free survival following BCG immunotherapy for NMIBC is associated with the accumulation of H3K4me3 at specific gene loci, and could lead to identification of prognostic biomarkers.

Cross-Generational Impact of Innate Immune Memory Following Pregnancy Complications.

Pregnancy complications can have long-term negative effects on the health of the affected mothers and their children. In this review, we highlight the underlying inflammatory etiologies of common pregnancy complications and discuss how aberrant inflammation may lead to the acquisition of innate immune memory. The latter can be described as a functional epigenetic reprogramming of innate immune cells following an initial exposure to an inflammatory stimulus, ultimately resulting in an altered response following re-exposure to a similar inflammatory stimulus. We propose that aberrant maternal inflammation associated with complications of pregnancy increases the cross-generational risk of developing noncommunicable diseases (i.e., pregnancy complications, cardiovascular disease, and metabolic disease) through a process mediated by innate immune memory. Elucidating a role for innate immune memory in the cross-generational health consequences of pregnancy complications may lead to the development of novel strategies aimed at reducing the long-term risk of disease.

Aberrant inflammation in rat pregnancy leads to cardiometabolic alterations in the offspring and intrauterine growth restriction in the F2 generation.

Children of women with pre-eclampsia have increased risk of cardiovascular (CV) and metabolic disease in adult life. Furthermore, the risk of pregnancy complications is higher in daughters born to women affected by pre-eclampsia than in daughters born after uncomplicated pregnancies. While aberrant inflammation contributes to the pathophysiology of pregnancy complications, including pre-eclampsia, the contribution of maternal inflammation to subsequent risk of CV and metabolic disease as well as pregnancy complications in the offspring remains unclear. Here, we demonstrate that 24-week-old female rats (F1) born to dams (F0) exposed to lipopolysaccharide (LPS) during pregnancy (to induce inflammation) exhibited mild systolic dysfunction, increased cardiac growth-related gene expression, altered glucose tolerance, and coagulopathy; whereas male F1 offspring exhibited altered glucose tolerance and increased visceral fat accumulation compared with F1 sex-matched offspring born to saline-treated dams. Both male and female F1 offspring born to LPS-treated dams had evidence of anemia. Fetuses (F2) from F1 females born to LPS-treated dams were growth restricted, and this reduction in fetal growth was associated with increased CD68 positivity (indicative of macrophage presence) and decreased expression of glucose transporter-1 in their utero-placental units. These results indicate that abnormal maternal inflammation can contribute to increased risk of CV and metabolic disease in the offspring, and that the effects of inflammation may cross generations. Our findings provide evidence in support of early screening for CV and metabolic disease, as well as pregnancy complications in offspring affected by pre-eclampsia or other pregnancy complications associated with aberrant inflammation.

TITAN: An end-to-end data analysis environment for the Hyperion™ imaging system.

Imaging Mass Cytometry (IMC) is a powerful high-throughput technique enabling resolution of up to 37 markers in a single fixed tissue section while also preserving in situ spatial relationships. Currently, IMC processing and analysis necessitates the use of multiple different software, labour-intensive pipeline development, different operating systems and knowledge of bioinformatics, all of which are a barrier to many potential users. Here we present TITAN - an open-source, single environment, end-to-end pipeline that can be utilized for image visualization, segmentation, analysis and export of IMC data. TITAN is implemented as an extension within the publicly available 3D Slicer software. We demonstrate the utility, application, reliability and comparability of TITAN using publicly available IMC data from recently-published breast cancer and COVID-19 lung injury studies. Compared with current IMC analysis methods, TITAN provides a user-friendly, efficient single environment to accurately visualize, segment, and analyze IMC data for all users.

Postpartum alterations following inflammation in rat pregnancy: a discovery proteomic analysis.

Women with a history of preeclampsia have an increased risk of subsequent cardiovascular and metabolic disease. While aberrant inflammation during pregnancy is associated with the development of preeclampsia, whether maternal inflammation increases the risk of disease later in life is unclear. Using a rat model we determined whether aberrant inflammation in pregnancy alters the levels of plasma proteins associated with cardiovascular and metabolic disease risk in the postpartum period. Pregnant rats were administered lipopolysaccharide (LPS) or saline on gestational days 13.5-16.5 to induce inflammation. Non-pregnant controls consisted of age-matched female rats subjected to similar administration of LPS or saline. Examination of the proteomic profile of plasma collected 16 weeks after delivery or from non-pregnant controls using liquid chromatography-tandem mass spectrometry revealed 100 differentially expressed proteins. Moreover, we identified 188 proteins in pregnant rats, of which 49 were differentially expressed in saline- vs LPS-treated dams. Of the 49 proteins regulated by LPS, 28 were pregnancy specific. PANTHER classification software, DAVID database and Ingenuity Pathways analysis revealed that the differentially expressed proteins in pregnant saline vs LPS-treated rats are associated with alterations in lipid and glucose metabolism and atherosclerosis, all of which may contribute to cardiovascular and metabolic disease risk. Results from proteomic and pathway analyses were validated by immunoassay of three serum proteins selected a priori and by assessment of serum metabolites. This discovery study demonstrates that aberrant inflammation during pregnancy results in long-lasting postpartum physiological alterations known to be associated with metabolic and cardiovascular disease.

Innate immune memory is associated with increased disease-free survival in bladder cancer patients treated with bacillus Calmette-Guérin.

INTRODUCTION: While studies suggest that innate immune memory acquired by circulating monocytes may mediate the benefit of bacillus Calmette-Guérin (BCG) in the treatment of patients with high-risk non-muscle-invasive bladder cancer (NMIBC), prospective studies are lacking. Innate immune memory is defined by enhanced release of pro-inflammatory cytokines by innate immune cells following a secondary challenge with pattern recognition receptor (PRR) ligands. METHODS: Peripheral blood monocytes isolated from 33 patients with intermediate- or high-risk NMIBC before and after two or five induction BCG instillations were stimulated with the PRR ligand lipopolysaccharide (LPS). Inflammatory cytokine levels in the culture medium were measured. Extent of innate immune memory acquisition was determined by dividing the levels of cytokines released after BCG instillation by the levels released prior to BCG therapy. RESULTS: Monocytes secreted variable levels of TNFα, IL-1ß, IL-6, IFNγ, IL-12, and IL-10. Compared with patients with recurrences, the post-BCG:pre-BCG ratio of IL-12 in monocyte cultures from patients without recurrences after five BCG instillations was significantly increased. Patients with no innate immune memory (based on IL-12 ratios) had significantly shorter time to recurrence than patients with innate immune memory (p<0.001). Eighty-four percent (16/19) of patients with innate immune memory vs. only 22% (2/9) of patients without memory had disease-free survival of over 500 days. CONCLUSIONS: Results demonstrate a potential link between BCG-induced innate immune memory peripherally and local anti-tumor responses. Further validation will increase our understanding of the mode of action of BCG and, therefore, will be used to enhance its effectiveness.

BCG vaccine and COVID-19: implications for infection prophylaxis and cancer immunotherapy.

The COVID-19 pandemic has killed over 400 000 people globally. Ecological evidence indicates that countries with national universal BCG vaccination programs for tuberculosis (TB) prevention have a much lower incidence of severe COVID-19 and mortality compared with those that do not have such programs. BCG is a century old vaccine used for TB prevention via infant/childhood vaccination in lowto middle-income countries with high infection prevalence rate and is known to reduce all-cause neonatal mortality. BCG remains the standard immunotherapy treatment for patients with high-risk non-muscle invasive bladder cancer globally for more than 44 years. Several trials are, therefore, investigating BCG as a prophylactic against COVID-19 in healthcare workers and the elderly. In this commentary, we discuss the potential mechanisms that may underlie BCG associated heterologous protection with a focus on tertiary lymphoid structure (TLS) organogenesis. Given the significance of TLSs in mucosal immunity, their association with positive prognosis and response to immune checkpoint blockade with a critical role of Type I interferon (IFN-1) in inducing these, we also discuss potentiating TLS formation as a promising approach to enhance anti-tumor immunity. We propose that lessons learned from BCG immunotherapy success could be applied to not only augment such microbe-based therapeutics but also lead to similar adjunctive IFN-1 activating approaches to improve response to immune checkpoint blockade therapy in cancer.

Inhibition of hypoxia-inducible factor 1α accumulation by glyceryl trinitrate and cyclic guanosine monophosphate.

A key mechanism mediating cellular adaptive responses to hypoxia involves the activity of hypoxia-inducible factor 1 (HIF-1), a transcription factor composed of HIF-1α, and HIF-1ß subunits. The classical mechanism of regulation of HIF-1 activity involves destabilisation of HIF-1α via oxygen-dependent hydroxylation of proline residues and subsequent proteasomal degradation. Studies from our laboratory revealed that nitric oxide (NO)-mediated activation of cyclic guanosine monophosphate (cGMP) signalling inhibits the acquisition of hypoxia-induced malignant phenotypes in tumour cells. The present study aimed to elucidate a mechanism of HIF-1 regulation involving NO/cGMP signalling. Using human DU145 prostate cancer cells, we assessed the effect of the NO mimetic glyceryl trinitrate (GTN) and the cGMP analogue 8-Bromo-cGMP on hypoxic accumulation of HIF-1α. Concentrations of GTN known to primarily activate the NO/cGMP pathway (100 nM-1 µM) inhibited hypoxia-induced HIF-1α protein accumulation in a time-dependent manner. Incubation with 8-Bromo-cGMP (1 nM-10 µM) also attenuated HIF-1α accumulation, while levels of HIF-1α mRNA remained unaltered by exposure to GTN or 8-Bromo-cGMP. Furthermore, treatment of cells with the calpain (Ca2+-activated proteinase) inhibitor calpastatin attenuated the effects of GTN and 8-Bromo-cGMP on HIF-1α accumulation. However, since calpain activity was not affected by incubation of DU145 cells with various concentrations of GTN or 8-Bromo-cGMP (10 nM or 1 µM) under hypoxic or well-oxygenated conditions, it is unlikely that NO/cGMP signalling inhibits HIF-1α accumulation via regulation of calpain activity. These findings provide evidence for a role of NO/cGMP signalling in the regulation of HIF-1α, and hence HIF-1-mediated hypoxic responses, via a mechanism dependent on calpain.

Hypoxia-Induced Resistance to Chemotherapy in Cancer.

A major barrier to the successful management of cancer is the development of resistance to therapy. Chemotherapy resistance can either be an intrinsic property of malignant cells developed prior to therapy, or acquired following exposure to anti-cancer drugs. Given the impact of drug resistance to the overall poor survival of cancer patients, there is an urgent need to better understand the molecular pathways regulating this malignant phenotype. In this chapter we describe some of the molecular pathways that contribute to drug resistance in cancer, the role of a microenvironment deficient in oxygen (hypoxia) in malignant progression, and how hypoxia can be a significant factor in the development of drug resistance. We conclude by proposing potential therapeutic approaches that take advantage of a hypoxic microenvironment to chemosensitize therapy-resistant tumours.

PTEN-deficient prostate cancer is associated with an immunosuppressive tumor microenvironment mediated by increased expression of IDO1 and infiltrating FoxP3+ T regulatory cells.

BACKGROUND: Accumulating evidence shows that tumor cell-specific genomic changes can influence the cross talk between cancer cells and the surrounding tumor microenvironment (TME). Loss of the PTEN tumor suppressor gene is observed in 20% to 30% of prostate cancers (PCa) when first detected and the rate increases with PCa progression and advanced disease. Recent findings implicate a role for PTEN in cellular type I interferon response and immunosuppression in PCa. However, the way that PTEN inactivation alters antitumor immune response in PCa is poorly understood. MATERIALS AND METHODS: To investigate the changes associated with PTEN loss and an immunosuppressive TME in PCa, we used CIBERSORT to estimate the relative abundance of 22 immune-cell types from 741 primary and 96 metastatic tumors. Our in silico findings were then validated by immunohistochemical analysis of immune cells and IDO1 and PDL1 checkpoint proteins in a cohort of 94 radical prostatectomy specimens. RESULTS: FoxP3+ T regulatory cells (Tregs) were significantly increased in PTEN-deficient PCa in all three public domain cohorts. Loss of PTEN in bone metastases was associated with lower CD8+ T-cell abundance, but in liver metastasis, FoxP3+ Tregs were present at higher levels. PTEN-deficient lymph node metastasis had a distinct profile, with high levels of CD8+ T cells. Moreover, we found that metastatic PCa presents higher abundance of FoxP3+ Treg when compared to primary lesions. Since PTEN-deficient tumors are likely to be immunosuppressed as a consequence of increased FoxP3+ Tregs, we then evaluated the localization and expression of IDO1, PDL1 immune checkpoints, and the corresponding density of FoxP3+ Treg and CD8+ T cells using our validation cohort (n = 94). We found that IDO1 protein expression and FoxP3+ Treg density were higher in neoplastic glands compared with benign adjacent tissue. Moreover, higher densities of FoxP3+ Treg cells in both stromal (P = 0.04) and tumor (P = 0.006) compartments were observed in PTEN-deficient tumors compared to tumors that retained PTEN activity. Similarly, IDO1 protein expression was significantly increased in the tumor glands of PTEN-deficient PCa (P < 0.0001). Spearman correlation analysis showed that IDO1 expression was significantly associated with FoxP3+ Treg and CD8+ T-cell density (P < 0.01). CONCLUSIONS: Our findings imply that PTEN deficiency is linked to an immunosuppressive state in PCa with distinct changes in the frequency of immune cell types in tumors from different metastatic sites. Our data suggest that determining PTEN status may also help guide the selection of patients for future immunotherapy trials in localized and metastatic PCa.

Thromboelastographic analysis of haemostasis in preeclamptic and normotensive pregnant women.

: Pregnancy is a state of heightened coagulation, exacerbated in pathological conditions such as preeclampsia. We evaluated the role of thromboelastography (TEG), compared with standard haemostasis tests, in identifying in haemostatic alterations in normotensive pregnancies and pregnancies complicated with preeclampsia. Standard haemostasis tests and TEG were performed on 28 normotensive women and 31 with preeclampsia at delivery, 6 weeks and 6 months postpartum. Results were compared between patient groups, and at different collection times. Standard haemostasis tests failed to reveal consistent differences in haemostatic function between subject groups, mirroring the inconsistency described in the literature. TEG revealed increased coagulability in preeclampsia subjects compared with normotensive subjects at delivery. Haemostatic alterations were normalized by 6 weeks postpartum and remained stable at 6 months postpartum. TEG is superior to standard laboratory haemostatic tests in evaluating antenatal and postpartum haemostatic alterations associated with pregnancy complications such as preeclampsia.

The Hippo Pathway Component TAZ Promotes Immune Evasion in Human Cancer through PD-L1.

The Hippo pathway component WW domain-containing transcription regulator 1 (TAZ) is a transcriptional coactivator and an oncogene in breast and lung cancer. Transcriptional targets of TAZ that modulate immune cell function in the tumor microenvironment are poorly understood. Here, we perform a comprehensive screen for immune-related genes regulated by TAZ and its paralog YAP using NanoString gene expression profiling. We identify the immune checkpoint molecule PD-L1 as a target of Hippo signaling. The upstream kinases of the Hippo pathway, mammalian STE20-like kinase 1 and 2 (MST1/2), and large tumor suppressor 1 and 2 (LATS1/2), suppress PD-L1 expression while TAZ and YAP enhance PD-L1 levels in breast and lung cancer cell lines. PD-L1 expression in cancer cell lines is determined by TAZ activity and TAZ/YAP/TEAD increase PD-L1 promoter activity. Critically, TAZ-induced PD-L1 upregulation in human cancer cells is sufficient to inhibit T-cell function. The relationship between TAZ and PD-L1 is not conserved in multiple mouse cell lines, likely due to differences between the human and mouse PD-L1 promoters. To explore the extent of divergence in TAZ immune-related targets between human and mouse cells, we performed a second NanoString screen using mouse cell lines. We show that many targets of TAZ may be differentially regulated between these species. These findings highlight the role of Hippo signaling in modifying human/murine physiologic/pathologic immune responses and provide evidence implicating TAZ in human cancer immune evasion.Significance: Human-specific activation of PD-L1 by a novel Hippo signaling pathway in cancer immune evasion may have a significant impact on research in immunotherapy. Cancer Res; 78(6); 1457-70. ©2018 AACR.

Comprehensive immune transcriptomic analysis in bladder cancer reveals subtype specific immune gene expression patterns of prognostic relevance.

Recent efforts on genome wide profiling of muscle invasive bladder cancer (MIBC) have led to its classification into distinct genomic and transcriptomic molecular subtypes that exhibit variability in prognosis. Evolving evidence from recent immunotherapy trials has demonstrated the significance of pre-existing tumour immune profiles that could guide treatment decisions. To identify immune gene expression patterns associated with the molecular subtypes, we performed a comprehensive in silico immune transcriptomic profiling, utilizing transcriptomic data from 347 MIBC cases from The Cancer Genome Atlas (TCGA). To investigate subtype-associated immune gene expression patterns, we assembled 924 immune response genes and specifically those involved in T-cell cytotoxicity and the Type I/II interferon pathways. A set of 157 ranked genes was able to distinguish the four subtypes in an unsupervised analysis in an original training cohort (n=122) and an expanded, validation cohort (n=225). The most common overrepresented pathways distinguishing the four molecular subtypes, included JAK/STAT signaling, Toll-like receptor signaling, interleukin signaling, and T-cell activation. Some of the most enriched biological processes were responses to IFN-γ, antigen processing and presentation, cytokine mediated signaling, hemopoeisis, cell proliferation and cellular defense response in the TCGA cluster IV. Our novel findings provide further insights into the association between genomic subtypes and immune activation in MIBC and may open novel opportunities for their exploitation towards precise treatment with immunotherapy.

Persistence of risk factors associated with maternal cardiovascular disease following aberrant inflammation in rat pregnancy.

INTRODUCTION: Pre-eclampsia is associated with increased risk of subsequent cardiovascular and metabolic disease in the affected mothers. While aberrant inflammation contributes to the pathophysiology of pre-eclampsia, it is unclear whether maternal inflammation contributes to the increased risk of disease. Here, we determined the effect of aberrant inflammation in pregnancy on cardiovascular and metabolic disease risk factors. METHODS: Wistar rats were administered low doses of lipopolysaccharide (LPS) on gestational days (GD) 13.5-16.5 to induce inflammation. Controls included pregnant rats treated with saline and nonpregnant rats treated with LPS or saline. We previously showed that LPS-treated pregnant rats exhibit key features of pre-eclampsia. Echocardiographic parameters, heart weight, blood pressure, blood lipids, pulse-wave velocity, and glucose tolerance, were assessed at 16 weeks postpartum. Messenger RNA levels of transcription factors associated with cardiac growth were measured in left ventricular tissue; histone modifications and global DNA methylation were determined in hearts and livers at GD 17.5 and at 16 weeks postpartum. RESULTS: Compared with saline-treated pregnant rats and nonpregnant rats treated with LPS or saline, LPS-treated pregnant rats exhibited left ventricular hypertrophy and increased blood cholesterol and low-density lipoprotein levels at 16 weeks postdelivery. LPS-treated rats had increased left ventricular mRNA levels of hypertrophy-associated transcription factors at GD 17.5 and increased levels of modified histones in hearts and livers at GD 17.5 and 16 weeks postpartum. Other parameters remained unchanged. CONCLUSION: Aberrant inflammation during pregnancy results in persistent alterations in maternal physiological parameters and epigenetic modifications that could contribute to the pathophysiology of cardiovascular disease.

Hypoxia reduces mature hERG channels through calpain up-regulation.

Human ether-a-go-go-related gene (hERG) encodes the pore-forming subunit of the rapidly activating delayed rectifier potassium current (IKr) potassium channel, which is important for cardiac repolarization. Impairment of hERG function is the primary cause of acquired long QT syndrome, which predisposes individuals to cardiac arrhythmias and sudden death. Patients with hypoxia due to conditions such as cardiac ischemia or obstructive sleep apnea display increased incidence of cardiac arrhythmias and sudden death. We sought to understand the mechanisms that underlie hypoxia-associated cardiac arrhythmias. Using cell biology and electrophysiologic techniques, we found that hypoxic culture of hERG-expressing human embryonic kidney (HEK) cells and neonatal rat cardiomyocytes reduced hERG current/IKr and mature ERG channel expression with a concomitant increase in calpain expression. Calpain was actively released into the extracellular milieu and degraded cell-surface hERG. In contrast to hERG, the ether-a-go-go (EAG) channel was not reduced by hypoxic culture. By making chimeric channels between hERG and EAG, we identified that hypoxia-induced calpain degraded hERG by targeting its extracellular S5-pore linker. The scorpion toxin BeKm-1, which is known to selectively bind to the S5-pore linker of hERG, prevented hypoxia-induced hERG reduction. Our data provide novel information about hypoxia-mediated hERG dysfunction and may have biological and clinical implications in hypoxia-associated diseases.-Lamothe, S. M., Song, W., Guo, J., Li, W., Yang, T., Baranchuk, A., Graham, C. H., Zhang, S. Hypoxia reduces mature hERG channels through calpain up-regulation.