Citations

Respiratory viral infections, like IAV and respiratory syncytial virus (RSV) infections, impose great challenges to public health. Alveolar macrophages (AM) are lung-resident immune cells that play important roles in protecting the host against IAV and RSV infections. However, the underlying molecular mechanisms by which AM modulate host inflammation, disease development, and tissue recovery are not very well understood. Here we identify that PPAR-γ expression in AM is crucial to suppress pulmonary inflammation and diseases and to promote fast host recovery from IAV and RSV infections. Our data suggest that targeting macrophage PPAR-γ may be a promising therapeutic option in the future to suppress acute inflammation and simultaneously promote recovery from severe diseases associated with respiratory viral infections.

Background We sought to study the prevalence of high‐sensitivity troponin and its association with cardiac structure and outcomes in ambulatory and hospitalized patients with heart failure with a preserved ejection fraction ( HF p EF ). Methods and Results A post hoc analysis utilized data from HF p EF patients: DOSE (Diuretic Optimization Strategies Evaluation) and CARRESS ‐ HF (Cardiorenal Rescue Study in Acute Decompensated Heart Failure) enrolled patients hospitalized with acute HF p EF , and RELAX (Phosphodiesterase‐5 Inhibition to Improve Clinical Status and Exercise Capacity in Heart Failure With Preserved Ejection Fraction) enrolled ambulatory patients with HF p EF . High‐sensitivity troponin I (hs‐TnI) was measured in hospitalized patients at baseline, at 72 to 96 hours, on day 7, and on day 60. In ambulatory patients hs‐TnI was measured at baseline and at week 24. In the ambulatory cohort, correlations between hs‐TnI and cardiac structure and function were assessed. The association between hs‐TnI and a 60‐day composite of emergency room visits, readmissions, and death was assessed for hospitalized patients using multivariable Cox proportional hazard models. The study population included 139 hospitalized and 212 ambulatory patients with HF p EF and hs‐TnI measured at baseline. The median (25th, 75th percentiles) baseline troponin was 17.6 (11.1, 41.0) ng/L in hospitalized patients and 9.5 (5.3, 19.7) ng/L in ambulatory patients ( P <0.001). The prevalence of elevated hs‐TnI (>99% percentile upper reference limit was 86% in hospitalized patients and 53% among ambulatory patients, with stable elevation in ambulatory patients during follow‐up. HF p EF patients with a hs‐TnI above the median were older with worse left ventricular hypertrophy and diastolic dysfunction. Continuously valued hs‐TnI (per doubling) was associated with increased risk of composite end point (adjusted hazard ratio 1.20, 95% confidence interval 1.00‐1.43; P =0.042). Conclusions Hs‐TnI is commonly elevated among both hospitalized and ambulatory patients with HF p EF . Increased hs‐TnI levels are associated with worse cardiac structure and increased risk of adverse events.

The prevalence of Lynch syndrome (LS) varies significantly in different populations, suggesting that ethnic features might play an important role. We enrolled 3330 consecutive Chinese patients who had surgical resection for newly diagnosed colorectal cancer. Universal screening for LS was implemented, including immunohistochemistry for mismatch repair (MMR) proteins, BRAFV600E mutation test and germline sequencing. Among the 3250 eligible patients, MMR protein deficiency (dMMR) was detected in 330 (10.2%) patients. Ninety‐three patients (2.9%) were diagnosed with LS. Nine (9.7%) patients with LS fulfilled Amsterdam criteria II and 76 (81.7%) met the revised Bethesda guidelines. Only 15 (9.7%) patients with absence of MLH1 on IHC had BRAFV600E mutation. One third (33/99) of the MMR gene mutations have not been reported previously. The age of onset indicates risk of LS in patients with dMMR tumors. For patients older than 65 years, only 2 patients (5.7%) fulfilling revised Bethesda guidelines were diagnosed with LS. Selective sequencing of all cases with dMMR diagnosed at or below age 65 years and only of those dMMR cases older than 65 years who fulfill revised Bethesda guidelines results in 8.2% fewer cases requiring germline testing without missing any LS diagnoses. While the prevalence of LS in Chinese patients is similar to that of Western populations, the spectrum of constitutional mutations and frequency of BRAFV600E mutation is different. Patients older than 65 years who do not meet the revised Bethesda guidelines have a low risk of LS, suggesting germline sequencing might not be necessary in this population.

Pancreatic cancer, mostly pancreatic ductal adenocarcinoma (PDAC), is one of the most lethal cancer types, with an estimated 44,330 death in 2018 in the US alone. While targeted therapies and immune checkpoint inhibitors have significantly improved treatment options for patients with lung cancer and renal cell carcinomas, little progress has been made in pancreatic cancer, with a dismal 5-year survival rate currently at ~8%. Upon diagnosis, the majority of pancreatic cancer cases (~80%) are already metastatic. Thus, identifying ways to reduce pancreatic cancer metastasis is an unmet medical need. Furthermore, pancreatic cancer is notorious resistant to chemotherapy. While Kirsten RAt Sarcoma virus oncogene (K-RAS) mutation is the major driver for pancreatic cancer, specific inhibition of RAS signaling has been very challenging, and combination therapy is thought to be promising. In this study, we report that combination of hedgehog (Hh) and Mitogen-activated Protein/Extracellular Signal-regulated Kinase Kinase (MEK) signaling inhibitors reduces pancreatic cancer metastasis in mouse models. In mouse models of pancreatic cancer metastasis using human pancreatic cancer cells, we found that Hh target gene Gli1 is up-regulated during pancreatic cancer metastasis. Specific inhibition of smoothened signaling significantly altered the gene expression profile of the tumor microenvironment but had no significant effects on cancer metastasis. By combining Hh signaling inhibitor BMS833923 with RAS downstream MEK signaling inhibitor AZD6244, we observed reduced number of metastatic nodules in several mouse models for pancreatic cancer metastasis. These two inhibitors also decreased cell proliferation significantly and reduced CD45+ cells (particularly Ly6G+CD11b+ cells). We demonstrated that depleting Ly6G+ CD11b+ cells is sufficient to reduce cancer cell proliferation and the number of metastatic nodules. In vitro, Ly6G+ CD11b+ cells can stimulate cancer cell proliferation, and this effect is sensitive to MEK and Hh inhibition. Our studies may help design novel therapeutic strategies to mitigate pancreatic cancer metastasis.

The expansion and accumulation of HIV-infected BCL6 + Tfh CD4 + T cells are thought to contribute to the persistence of viral reservoirs in infected subjects undergoing ART. Two mechanisms have been raised for the preferential retention of HIV within Tfh CD4 + T cells: (i) antiretroviral drugs have limited tissue distribution, resulting in insufficient tissue concentration and lower efficacy in controlling HIV replication in lymphoid tissues, and (ii) cytotoxic CD8 + T cells within lymphoid tissues express low levels of chemokine receptor (CXCR5), thus limiting their ability to enter the GCs to control/eliminate HIV-infected Tfh cells. Our results indicate that the BCL6 inhibitor FX1 can not only repress HIV infection of tonsillar Tfh ex vivo but also suppress HIV infection and reactivation in primary, non-Tfh CD4 + T cells. Our study provides a rationale for targeting BCL6 protein to extend ART-mediated reduction of persistent HIV and/or support strategies toward HIV remission beyond ART cessation.

T cell responses to subunit vaccination require both IL-27 and IL-15 to support an aerobic glycolysis–independent metabolic program.

BackgroundHeart rate and systolic blood pressure (SBP) are prognostic markers in heart failure (HF) with reduced ejection fraction (HFrEF). Their combination in rate pressure product (RPP) as well as their role in heart failure with preserved ejection fraction (HFpEF) remains unclear.HypothesisRPP and its components are associated with HFpEF outcomes.MethodsWe performed an analysis of Acute Study of Clinical Effectiveness of Nesiritide in Subjects With Decompensated Heart Failure (ASCEND‐HF; http://www.clinicaltrials.gov NCT00475852), which studied 7141 patients with acute HF. HFpEF was defined as left ventricular ejection fraction ≥40%. Outcomes were assessed by baseline heart rate, SBP, and RPP, as well as the change of these variables using adjusted Cox models.ResultsAfter multivariable adjustment, in‐hospital change but not baseline heart rate, SBP, and RPP were associated with 30‐day mortality/HF hospitalization (hazard ratio [HR]: 1.17 per 5‐bpm heart rate, HR: 1.20 per 10‐mm Hg SBP, and HR: 1.02 per 100 bpm × mm Hg RPP; all P < 0.05). Baseline SBP was associated with 180‐day mortality (HR: 0.88 per 10‐mm Hg, P = 0.028). Though change in RPP was associated with 30‐day mortality/HF hospitalization, the RPP baseline variable did not provide additional associative information with regard to outcomes when compared with assessment of baseline heart rate and SBP variables alone.ConclusionsAn increase in heart rate and SBP from baseline to discharge was associated with increased 30‐day mortality/HF hospitalization in HFpEF patients with acute exacerbation. These findings suggest value in monitoring the trend of vital signs during HFpEF hospitalization.

Abstract Aims The incidence of and factors associated with sudden cardiac death (SCD) early after an acute heart failure (HF) hospital admission have not been well defined. Methods and results We assessed SCD and ventricular arrhythmias in the Acute Study of Clinical Effectiveness of Nesiritide in Decompensated Heart Failure (ASCEND-HF) trial, which included patients with acute HF with reduced or preserved ejection fraction. SCD, resuscitated SCD (RSCD), and sustained ventricular tachycardia/ventricular fibrillation (VT/VF) were adjudicated from randomization through 30 days and were combined into a composite endpoint. Baseline characteristics associated with this composite were determined by logistic regression. RSCD and VT/VF were included as time-dependent variables in a Cox model evaluating the association of these variables with 180-day all-cause mortality. Among 7011 patients, the 30-day all-cause mortality rate was 3.8%; SCD accounted for 17% of these deaths. The 30-day composite event rate was 1.8% (n = 121). Ten patients had more than one event with 30-day Kaplan–Meier event rates of 0.6% for SCD [95% confidence interval (CI) 0.5%–0.9%, n = 43], 0.4% for RSCD (95% CI 0.2%–0.5%, n = 24), and 0.9% for VT/VF (95% CI 0.7%–1.2%, n = 64). In the multivariable model, chronic obstructive pulmonary disease, history of VT, male sex, and longer QRS duration were associated with SCD, RSCD, or VT/VF. A RSCD or VT/VF event was associated with higher 180-day mortality (adjusted hazard ratio 6.6, 95% CI 4.8–9.1, P &lt; 0.0001). Conclusions Approximately 2% of patients admitted for acute HF experienced SCD, RSCD, or VT/VF within 30 days of admission, and SCD accounted for 17% of all deaths within 30 days.

Abstract IFN regulatory factor 4 (IRF4) is a key transcription factor that promotes effector CD8+ T cell differentiation and expansion. The roles of IRF4 in regulating the CD8+ T cell response to cytokines have not been explored. In this article, we show that IL-2 and IL-15 signaling and STAT5 activation regulate IRF4 expression in CD8+ T cells. Gene-expression profile analysis has also revealed that IRF4 is required for expression of the receptors of IL-2 family cytokines CD122 and CD127. We found that IRF4 binds directly to CD122 and CD127 gene loci, indicating that it may directly promote CD122 and CD127 gene transcription. As a consequence, IRF4-deficient CD8+ T cells show diminished sensitivity to IL-2, IL-15, and IL-7 treatment in vitro. Furthermore, we found that IRF4-deficient CD8+ T cells had lower expression of CD122 and CD127 in vivo during influenza virus infection. These data suggest that IRF4 regulates the sensitivity of CD8+ T cells to IL-2 family cytokines, which correlates with the diminished effector and memory CD8+ T cell responses in IRF4-deficient CD8+ T cells.

Abstract Follicular Th (Tfh) cells are a distinct subset of Th cells that help B cells produce class-switched antibodies. Studies have demonstrated that Tfh cells are highly prone to HIV infection and replication. However, the molecular mechanisms underlying this phenomenon are largely unclear. Here, we show that murine and human Tfh cells have diminished constitutive expression of IFN-stimulated genes (ISGs) inclusive of antiviral resistance factor MX dynamin-like GTPase 2 (MX2) and IFN-induced transmembrane 3 (IFITM3) compared with non-Tfh cells. A lower antiviral resistance in Tfh was consistent with a higher susceptibility to retroviral infections. Mechanistically, we found that BCL6, a master regulator of Tfh cell development, binds to ISG loci and inhibits the expression of MX2 and IFITM3 in Tfh cells. We demonstrate further that inhibition of the BCL6 BR-C, ttk, and bab (BTB) domain function increases the expression of ISGs and suppresses HIV infection and replication in Tfh cells. Our data reveal a regulatory role of BCL6 in inhibiting antiviral resistance factors in Tfh cells, thereby promoting the susceptibility Tfh cells to viral infections. Our results indicate that the modulation of BCL6 function in Tfh cells could be a potential strategy to enhance Tfh cell resistance to retroviral infections and potentially decrease cellular reservoirs of HIV infection.