Project description:Exposure to cardiopulmonary bypass (CPB) during cardiac surgery results in a significant inflammatory response that contributes to morbidity and mortality, which is especially prominent in neonatal patients. The molecular and cellular mechanisms that underpin this inflammatory process remain poorly understood. To gain deeper insight, we performed snRNA and snATAC sequencing on peripheral blood mononuclear cells (PBMCs) isolated from neonatal CPB patients prior to start of CPB, at the end of CPB, as well as 8 and 24 hours after CPB. The dramatic increase in the proportion of classic monocytes following bypass surgery indicates their essential role in inflammation associated with cardiopulmonary bypass (CPB). Immune dysregulation exhibited at activation of inflammatory genes in classical monocytes, as well as in other cell types, after CPB exposure. A series of in vitro experiments in non-adherent monocytic cells identified two novel genes SPTAN1 and RAF1 as effectors of hemodynamic stress. These two genes promoted STIM1 coupling to ORAI1 channel leading to calcium icon influx, thereby driving inflammation and cell death. snATAC-Seq revealed dynamically changing patterns of chromatin accessibility and transcription factors JUN and FOS binding motifs being highly enriched in classical monocytes after CPB exposure. Increased calcium in turn stimulates JUN binding to DNA, as suggested by CUT&RUN data derived from shear stressed non-adherent monocytic cells. Together, these data indicate that shear stress via a calcium dependent mechanism contributes to the CPB-associated activation of classic monocytes. These findings provide deeper insight not only in the pathogenesis of CPB-associated inflammation, but also have implications for the understanding of early stages of sterile inflammation and how non-adherent cells “sense” shear stress.
Project description:The purpose of the present study was to investigate the activation of the cardiac inflammatory response in the hearts of SHAM (surgical opening of the chest) mice in comparison to CONTROL hearts isolated from naïve (not operated) mice. Male C57BL/6J (10 weeks) were subjected to an open-chest ischemia-reperfusion (I/R) SHAM procedure in order to examine the effects of this surgery alone in producing cardiac inflammation. The procedure consisted of thoracotomy and a suture passed around the left anterior descending artery (LAD). The mouse chest was kept open for approximately 45 min. We chose to study an open-chest I/R SHAM because this is the reference surgery for the most common surgical procedure used to study cardiac inflammation. Mice were sacrificed 5 days after the procedure and the hearts were removed and used in RNAseq experiments.
Project description:The goal of the study was to identify the gene changes that occur in the striatum of neonatal piglets exposed to cardiopulmonary bypass (CPB) with deep hypothermic cardiac arrest (DHCA) then recovered for 6h. To accomplish our goal, mRNA-seq was performed on RNA isolated from neonatal pigs exposed to either DHCA or sham conditions.
Project description:Renal insufficiency is a risk factor for development of cardiovascular disease. In this study our aim was to investigate functional and structural changes in the heart of dogs with mild renal insufficiency induced by uninephrectomy (UNX). In addition to comprehensively assessing functional parameters 12 week after UNX or sham surgery, we harvested tissue for assessment of structural changes. Microarray analyses were performed on snap frosen tissue from the left atrium (LA) and left ventricle (LV) of UNX and sham operated animals. Gene expression in LA was compared between the groups, and gene expression in the LV was compared between the groups. We aimed to assess whether a potentially altered gene expression in the heart of the UNX group also included genes associated with cardiac remodeling. Six dogs were assigned to unineprectomy and 6 dogs were assigned to sham operation. Microarray analyses were performed on 5 samples from the left atrium of uninephrectomized animals and on 5 samples from the left atrium of sham operated animals. Further, microarray analyses were performed on 5 samples from the left ventricle of uninephcretomized animals and on 5 samples from the left ventricle of sham operated animals. No replicates were perfomed.