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Background: Salt sensitivity of blood pressure is an independent predictor of cardiovascular morbidity and mortality. The exact mechanism by which salt intake increases blood pressure and cardiovascular risk is unknown. We previously found that sodium entry into antigen-presenting cells (APCs) via the amiloride-sensitive epithelial sodium channel EnaC (epithelial sodium channel) leads to the formation of IsoLGs (isolevuglandins) and release of proinflammatory cytokines to activate T cells and modulate salt-sensitive hypertension. In the current study, we hypothesized that ENaC-dependent entry of sodium into APCs activates the NLRP3 (NOD [nucleotide-binding and oligomerization domain]-like receptor family pyrin domain containing 3) inflammasome via IsoLG formation leading to salt-sensitive hypertension. Methods: We performed RNA sequencing on human monocytes treated with elevated sodium in vitro and Cellular Indexing of Transcriptomes and Epitopes by Sequencing analysis of peripheral blood mononuclear cells from participants rigorously phenotyped for salt sensitivity of blood pressure using an established inpatient protocol. To determine mechanisms, we analyzed inflammasome activation in mouse models of deoxycorticosterone acetate salt–induced hypertension as well as salt-sensitive mice with ENaC inhibition or expression, IsoLG scavenging, and adoptive transfer of wild-type dendritic cells into NLRP3 deficient mice. Results: We found that high levels of salt exposure upregulates the NLRP3 inflammasome, pyroptotic and apoptotic caspases, and IL (interleukin)-1β transcription in human monocytes. Cellular Indexing of Transcriptomes and Epitopes by Sequencing revealed that components of the NLRP3 inflammasome and activation marker IL-1β dynamically vary with changes in salt loading/depletion. Mechanistically, we found that sodium-induced activation of the NLRP3 inflammasome is ENaC and IsoLG dependent. NLRP3 deficient mice develop a blunted hypertensive response to elevated sodium, and this is restored by the adoptive transfer of NLRP3 replete APCs. Conclusions: These findings reveal a mechanistic link between ENaC, inflammation, and salt-sensitive hypertension involving NLRP3 inflammasome activation in APCs. APC activation via the NLRP3 inflammasome can serve as a potential diagnostic biomarker for salt sensitivity of blood pressure.

SummaryPersistent systemic inflammation in persons with HIV (PWH) is accompanied by an increased risk of metabolic disease. Yet, changes in the innate and adaptive immune system in PWH who develop metabolic disease remain poorly defined. Using unbiased approaches, we show that PWH with prediabetes/diabetes have a significantly higher proportion of circulating CD14+monocytes complexed to T cells. The complexed CD3+T cells and CD14+monocytes demonstrate functional immune synapses, increased expression of proinflammatory cytokines, and greater glucose utilization. Furthermore, these complexes harbor more latent HIV DNA compared to CD14+monocytes or CD4+T cells. Our results demonstrate that circulating CD3+CD14+T cell-monocyte pairs represent functional dynamic cellular interactions that likely contribute to inflammation and, in light of their increased proportion, may have a role in metabolic disease pathogenesis. These findings provide an incentive for future studies to investigate T cell-monocyte immune complexes as mechanistic in HIV cure and diseases of aging.Graphical AbstractHighlightsPersons with HIV and diabetes have increased circulating CD3+CD14+T cell-monocyte complexes.CD3+CD14+T cell-monocytes are a heterogenous group of functional and dynamic complexes.We can detect HIV in T cell-monocyte complexes.The proportion of CD3+CD14+T cell-monocyte complexes is positively associated with blood glucose levels and negatively with plasma IL-10 and CD4+T regulatory cells.

Background To characterize how antibiotic exposure impacts development and durability of intestinal dysbiosis and the acquisition of antibiotic resistance genes (ARGs) in the intestinal flora of premature infants in the Neonatal Intensive Care Unit (NICU), we established an infant gut microbiome biorepository (IGMB). Methods We performed prospective weekly stool collection in NICU patients meeting the following criteria: birthweight < 2000 g, postnatal age < 2 months and no diagnoses of congenital gut malformation or cyanotic heart disease. Cases were infants with bloodstream infections (BSI), defined as bacterial growth from blood culture; controls were infants with < 5 days of antibiotic exposure, no BSI nor necrotizing enterocolitis. We performed metagenomic analysis on 5–6 serial stool samples from each of the 10 cases and 10 controls (n= 100 stools). We used Wilcoxon rank sum tests for pairwise comparisons. Results From July 2021 to May 2022, 265 infants contributed 1,300 stool samples to the IGMB. In 7 of 8 BSI cases the causative pathogen was identified in the pre-BSI stool sample. Two more BSI cases did not have a pre-BSI stool sample. Microbiome species α-diversity increased with advancing postnatal age in controls but not in cases (Fig. 1). Among 6 cases with high beta lactam exposure ( >14 cumulative days by last stool collection), 3 had notable increases in the relative abundance of Enterococcus spp. (Fig. 2). Controls did not have similar trends in Enterococcus spp., but did have higher relative abundance of facultative anaerobes including Bifidobacterium, Lactobacillus, and Veillonella spp. (Fig. 3). Antibiotic resistance gene (ARG) abundance did not differ significantly between cases and controls. Conclusion Compared to controls, neonates with BSI have increased antibiotic intensity throughout their NICU admissions, reduction of microbial species diversity and overabundance of specific organisms in their gut microbiomes. We observed increased Enterococcus spp. prevalence with higher beta lactam exposure. ARG abundance did not differ between cases and controls. The clinical implications of this microbiome dysbiosis warrant further study. Disclosures Jörn-Hendrik Weitkamp, MD, Roche Diagnostics: Advisor/Consultant.

Salt sensitivity of blood pressure is an independent predictor of death due to cardiovascular events. Diagnosis of salt-sensitivity is not feasible in the clinic, making it difficult to investigate therapeutic strategies. We hypothesized that NLRP3-inflammasome and IL-1β production in monocytes plays a role in salt-sensitive hypertension. We phenotyped salt-sensitivity of blood pressure using an acute inpatient Weinberger protocol of an isocaloric high salt diet and rapid intravenous salt-loading, followed by low salt diet and furosemide-induced salt-depletion. Ambulatory blood pressure was continuously monitored and averaged for the days of salt-loading and salt-depletion. Blood samples were obtained at baseline, salt-loading, and after salt-depletion. Median age was 54 years (44-55), 3 of the 5 subjects were female, screening systolic blood pressure was 140 mmHg (134-148), diastolic blood pressure was 88 mmHg (84-99), and BMI was 35 kg/m 2 (30-39). Using cell hashing and ECCITE-seq analysis, we profiled transcriptomes in multiple immune cell types using antibody-derived tags (ADTs). UMAP clustering of different cell types were identified by ADTs including monocyte markers CD14 and CD16. Interestingly, UMAP visualization of CD14+ and CD16+ clusters indicated a greater decrease in CD14+ clusters after salt-depletion in the salt-resistant subjects than the salt-sensitive; however the salt-sensitive subjects had a greater decrease in CD16+ clusters than the salt-resistant group after both salt-loading and salt-depletion. These data were confirmed using flow cytometry. Unlike in salt-resistant participants, we found that within monocyte clusters, salt-sensitivity was associated with down regulation of the inflammasome components NLRP3 (0.386 ± 1.18 vs. 0.197 ± 0.778) and IL-1β (0.858 ± 2.32 vs. 0.159 ± 0.925) following salt-depletion. Using flow cytometry, we found Δ% isoLG+ CD14+/CD16+ monocytes correlated with salt-sensitivity of blood pressure (r=0.88, 95% CI, p=0.05). These results suggest that the inflammasome and monocyte activation are dynamically regulated by dietary salt in vivo and can serve as a potential diagnostic biomarker for salt-sensitivity of blood pressure.

We developed a metatranscriptomics method that can simultaneously capture the respiratory virome, microbiome, and host response directly from low-biomass clinical samples. Using nasal swab samples, we have demonstrated that this method captures the comprehensive RNA virome with sufficient sequencing depth required to assemble complete genomes. We find a surprisingly high-frequency of Respiratory Syncytial Virus (RSV) and Coronavirus (CoV) in healthy children, and a high frequency of RSV-A and RSV-B co-infections in children with symptomatic RSV. In addition, we have characterized commensal and pathogenic bacteria, and fungi at the species-level. Functional analysis of bacterial transcripts revealed H. influenzae was highly active in symptomatic RSV subjects. Host transcriptome shows upregulation of the innate immune system, antiviral response and inflammasome pathway, and down regulation of fatty-acids pathway. This method is broadly applicable to infer transcriptome landscape of an infected system, surveil respiratory infections, and to sequence RNA viruses directly from clinical samples.

Trabalho apresentado no Annual Meeting of the American Society of Tropical Medicine and Hygiene (ASTMH), 65th, 13 Nov. 2016.