Brief Report: Increased Cotinine Concentrations are Associated With Reduced Expression of Cathelicidin (LL-37) and NOD-2 in Alveolar Macrophages of PLWH Who Smoke.

There is a strong link between cigarette smoking and pulmonary complications among people living with HIV. However, the effects of smoking on the local lung immune environment in this population remain unclear. Bronchoalveolar lavage and saliva were collected from HIV-infected smokers involved in a prospective study investigating alveolar macrophage expression of host defense molecules. Salivary cotinine concentrations were inversely related to expression of the immune cell receptor nucleotide-binding oligomerization domain-2 and the cathelicidin antimicrobial peptide LL-37. The negative correlation between salivary cotinine and LL-37 was particularly strong. Our study provides insight into how nicotine may adversely affect lung innate immunity in HIV.

Association of Epigenetic Age and p16INK4a With Markers of T-Cell Composition in a Healthy Cohort.

How the measurement of aging biomarkers in peripheral blood T-lymphocytes (PBTLs) is influenced by cell composition is unclear. Here, we collected peripheral blood and isolated CD3+ PBTLs from 117 healthy couples between the ages of 21 and 72. Each sample was profiled for Horvath epigenetic clock (DNAm), p16INK4a expression, cytomegalovirus (CMV) seropositivity and 74 mRNA markers of PBTL subtype, differentiation, immune checkpoints, and cytokine production. Correlations between individual aging biomarkers (DNAm or p16INK4a) and PBTL mRNAs were corrected for chronological age, sex, and couple. DNAm measurements correlated with CMV seropositivity as well as PBTL mRNAs indicative of effector function (CD8A, EOMES, TBX21, GZMB), poor proliferative capacity (KLRG1, CD57), differentiation (CD45RO, CD45RA), and immune checkpoints (PDCD1, TIGIT, LAG3, CD160, CD244). In contrast, only three PBTL mRNAs, CD28, CD244, and p14ARF, showed a significant association with p16INK4a. p16INK4a expression also showed a weaker association with immunosenescent PBTL subsets than DNAm in flow cytometry analyses. These data suggest that PBTL composition has a greater influence on DNAm than p16INK4a and link accelerated epigenetic aging to immunosenescent phenotypes.

Inflammasome mRNA expression in human monocytes during early septic shock.

RATIONALE: Monocytes are central to the initiation of the inflammatory response in sepsis, with caspase-1 activation playing a key role. Monocyte deactivation during sepsis has been linked to poor outcomes. OBJECTIVES: Given the importance of caspase-1 in the immune response, we investigated whether monocytes from patients early in septic shock demonstrate alterations in mRNAs for caspase-1-related molecules. METHODS: Patients with septic shock (n = 26; age >18 years), critically ill intensive care unit patients (n = 20), and healthy volunteers (n = 22) were enrolled in a prospective cohort study in a university intensive care unit. Demographic, biological, physiologic, and plasma cytokine measurements were obtained. Monocytes were assayed for ex vivo tumor necrosis factor-alpha production, and fresh monocyte mRNA was analyzed by quantitative reverse-transcription polymerase chain reaction for Toll-like receptors, NOD-LRR proteins, cytokines, and nuclear factor-kappaB-related genes. MEASUREMENTS AND MAIN RESULTS: Relative copy numbers for the inflammasome mRNAs for ASC, caspase-1, NALP1, and Pypaf-7 were significantly lower in patients with septic shock compared with critically ill control subjects. NALP1 mRNA levels were linked to survival in patients with sepsis (P = 0.0068) and correlated with SAPS II scores (r = -0.63). CONCLUSIONS: These data suggest that monocyte deactivation occurs during the earliest stages of the systemic inflammatory response and that changes in inflammasome mRNA expression are part of this process.

Time-of-Day Dictates Transcriptional Inflammatory Responses to Cytotoxic Chemotherapy.

Many cytotoxic chemotherapeutics elicit a proinflammatory response which is often associated with chemotherapy-induced behavioral alterations. The immune system is under circadian influence; time-of-day may alter inflammatory responses to chemotherapeutics. We tested this hypothesis by administering cyclophosphamide and doxorubicin (Cyclo/Dox), a common treatment for breast cancer, to female BALB/c mice near the beginning of the light or dark phase. Mice were injected intravenously with Cyclo/Dox or the vehicle two hours after lights on (zeitgeber time (ZT2), or two hours after lights off (ZT14). Tissue was collected 1, 3, 9, and 24 hours later. Mice injected with Cyclo/Dox at ZT2 lost more body mass than mice injected at ZT14. Cyclo/Dox injected at ZT2 increased the expression of several pro-inflammatory genes within the spleen; this was not evident among mice treated at ZT14. Transcription of enzymes within the liver responsible for converting Cyclo/Dox into their toxic metabolites increased among mice injected at ZT2; furthermore, transcription of these enzymes correlated with splenic pro-inflammatory gene expression when treatment occurred at ZT2 but not ZT14. The pattern was reversed in the brain; pro-inflammatory gene expression increased among mice injected at ZT14. These data suggest that inflammatory responses to chemotherapy depend on time-of-day and are tissue specific.

Microvesicular caspase-1 mediates lymphocyte apoptosis in sepsis.

OBJECTIVE: Immune dysregulation during sepsis is poorly understood, however, lymphocyte apoptosis has been shown to correlate with poor outcomes in septic patients. The inflammasome, a molecular complex which includes caspase-1, is essential to the innate immune response to infection and also important in sepsis induced apoptosis. Our group has recently demonstrated that endotoxin-stimulated monocytes release microvesicles (MVs) containing caspase-1 that are capable of inducing apoptosis. We sought to determine if MVs containing caspase-1 are being released into the blood during human sepsis and induce apoptosis.. DESIGN: Single-center cohort study. MEASUREMENTS: 50 critically ill patients were screened within 24 hours of admission to the intensive care unit and classified as either a septic or a critically ill control. Circulatory MVs were isolated and analyzed for the presence of caspase-1 and the ability to induce lymphocyte apoptosis. Patients remaining in the ICU for 48 hours had repeated measurement of caspase-1 activity on ICU day 3. MAIN RESULTS: Septic patients had higher microvesicular caspase-1 activity 0.05 (0.04, 0.07) AFU versus 0.0 AFU (0, 0.02) (p<0.001) on day 1 and this persisted on day 3, 0.12 (0.1, 0.2) versus 0.02 (0, 0.1) (p<0.001). MVs isolated from septic patients on day 1 were able to induce apoptosis in healthy donor lymphocytes compared with critically ill control patients (17.8±9.2% versus 4.3±2.6% apoptotic cells, p<0.001) and depletion of MVs greatly diminished this apoptotic signal. Inhibition of caspase-1 or the disruption of MV integrity abolished the ability to induce apoptosis. CONCLUSION: These findings suggest that microvesicular caspase-1 is important in the host response to sepsis, at least in part, via its ability to induce lymphocyte apoptosis. The ability of microvesicles to induce apoptosis requires active caspase-1 and intact microvesicles.

A comparison of zinc metabolism, inflammation, and disease severity in critically ill infected and noninfected adults early after intensive care unit admission.

BACKGROUND: Zinc deficiency is a cause of immune dysfunction and infection. Previous human studies have shown that the activation of the acute phase response alters zinc metabolism. Whether the alteration in zinc metabolism is predictive of disease severity in the setting of critical illness is unclear. OBJECTIVE: We sought to determine whether differences occur in zinc metabolism at the onset of critical illness between infected (septic) and noninfected subjects. DESIGN: We conducted this prospective study in an adult medical intensive care unit (MICU) at a tertiary care hospital. Subjects were enrolled within 24 h of intensive care unit admission. Subjects who did not meet sepsis criteria were considered for the critically ill control (CIC) arm. After patient consent, blood was immediately collected to measure plasma zinc and cytokine concentrations and zinc transporter gene expression in peripheral blood monocytes. Clinical data during the MICU stay were also recorded. RESULTS: A total of 56 patients were evaluated (22 septic, 22 CIC, and 12 healthy subjects). Plasma zinc concentrations were below normal in CIC patients and further reduced in the septic cohort (57.2 ± 18.2 compared with 45.5 ± 18.1 µg/dL). Cytokine concentrations increased with decreasing plasma zinc concentrations (P = 0.05). SLC39A8 gene expression was highest in patients with the lowest plasma zinc concentrations and the highest severity of illness. CONCLUSIONS: The alteration of zinc metabolism was more pronounced in septic patients than in noninfected critically ill patients. Specifically, sepsis was associated with lower plasma zinc concentrations and higher SLC39A8 mRNA expression, which correlated with an increased severity of illness, including cardiovascular dysfunction.