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There is considerable evidence that the immune system plays a role in hypertension, however this role is not fully characterized. Our previous studies demonstrated that mesenteric perivascular adipose tissue (mPVAT) harbors a large T cell population, which is a cell type identified as contributing to hypertension. In the present study, we tested the hypothesis that soluble mediators in mPVAT influence T cell function just prior to the development of hypertension. Toward this end, we utilized a unique model of hypertension in which Dahl S rats on a high fat (HF) diet develop hypertension. We found that conditioned media (CM) from mPVAT from healthy Dahl S rats on control diet buffers T cell activation, however, mPVAT-CM from Dahl S rats on a HF diet markedly increased inflammatory cytokine induction (IFNγ, GM-CSF and IL-17a) by activated T cells. These cytokines are known to promote activation of macrophages and neutrophils, among other effects. Conversely, the anti-inflammatory cytokine, IL-10, was not different between the groups, suggesting the effect is selective for inflammatory cytokines. Furthermore, we conducted bulk RNA-seq on activated T cells cultured in mPVAT-CM from Dahl S rats on either control (CTL) or HF diet for 10 weeks. In accordance with the cytokine analysis, mPVAT-CM from HF diet-fed rats significantly upregulated many genes associated with IFNγ/IL-17 induction, whereas Th2/Treg-associated genes were downregulated. Taken together, these data strongly suggest soluble mediators from mPVAT influence T cell inflammatory status and may promote Th1/Th17 differentiation preceding the development of hypertension triggered by HF diet. [ABSTRACT FROM AUTHOR]

Graduate students and postdocs in science, technology, engineering, and math fields are faced with a wide range of career paths to employment, but they are often not trained to effectively pursue these opportunities. The lack of career management skills implies long tenures in graduate school for many students, especially as tenure-track positions in academia dwindle. At our university, we used a cohort model in which graduate students and postdocs were encouraged to apply to the Broadening Experiences in Scientific Training program (BEST under the aegis of the National Institutes of Health) that provided opportunities to gain career management skills, engage in career exploration, and complete at least one formal internship. In this interview study of the BEST trainees, we investigated the efficacy of internships as career exploration tools and associated outcomes. Our findings show that internships were seen as effective career exploration and self-development vehicles that influenced participants' long-term career goals. Graduate students and postdocs reported gaining transferable knowledge and skills, in addition to receiving valuable industry mentoring and networking opportunities.

Perivascular adipose tissue (PVAT) regulates vascular function due to its capacity to synthesize vasoactive products and its mechanical properties. PVATs most abundant cells are adipocytes, and their populations are maintained by the maturation of adipocyte progenitor cells (APC), which may play a pivotal role in the pathogenesis of cardiovascular diseases. However, the distribution of APC within PVAT depots, their potential variation in spatial location, and the influence of sex and age on their abundance remain unknown. We hypothesize that APC abundance in PVAT is affected by location, age, sex and that APC subtypes have specific spatial distributions. PVAT from thoracic and abdominal aorta, and mesenteric arteries, and AT from interscapular, gonadal, and subcutaneous depots from 13-week and 30-week-old females and males Pdgfrα-CreERT2 x LSLtdTomato mice (n = 28) were analyzed. Abdominal aorta PVAT had fewer progenitors than mesenteric PVAT and gonadal AT. Aging reduced the abundance of APC in the thoracic aorta but increased their numbers in mesenteric PVAT. Females had more APC than males in mesenteric PVAT and gonadal AT depots. APC exhibited unique spatial distribution in the aorta and mesenteric PVAT where they localized neighboring vasa vasorum and arteries. APC subtypes (APC1, APC2, APC3, diff APC) were identified in all PVAT depots. Thoracic aorta PVAT APC3 were located in the adventitia while diff APC were in the parenchyma. This study identified variability in APC populations based on depot, age, and sex. The distinctive spatial distribution and the presence of diverse APC subtypes suggest that they may contribute differently to cardiovascular diseases-induced PVAT remodeling. [ABSTRACT FROM AUTHOR]

Perivascular adipose tissue (PVAT) is increasingly recognized for its function in mechanotransduction. However, major gaps remain in our understanding of the cells present in PVAT, as well as how different cells contribute to mechanotransduction. We hypothesized that snRNA-seq would reveal the expression of mechanotransducers, and test one (PIEZO1) to illustrate the expression and functional agreement between single-nuclei RNA sequencing (snRNA-seq) and physiological measurements. To contrast two brown tissues, subscapular brown adipose tissue (BAT) was also examined. We used snRNA-seq of the thoracic aorta PVAT (taPVAT) and BAT from male Dahl salt-sensitive (Dahl SS) rats to investigate cell-specific expression mechanotransducers. Localization and function of the mechanostransducer PIEZO1 were further examined using immunohistochemistry (IHC) and RNAscope, as well as pharmacological antagonism. Approximately 30,000 nuclei from taPVAT and BAT each were characterized by snRNA-seq, identifying eight major cell types expected and one unexpected (nuclei with oligodendrocyte marker genes). Cell-specific differential gene expression analysis between taPVAT and BAT identified up to 511 genes (adipocytes) with many (≥20%) being unique to individual cell types. Piezo1 was the most highly, widely expressed mechanotransducer. The presence of PIEZO1 in the PVAT but not the adventitia was confirmed by RNAscope and IHC in male and female rats. Importantly, antagonism of PIEZO1 by GsMTX4 impaired the PVAT's ability to hold tension. Collectively, the cell compositions of taPVAT and BAT are highly similar, and PIEZO1 is likely a mechanotransducer in taPVAT. NEW & NOTEWORTHY This study describes the atlas of cells in the thoracic aorta perivascular adipose tissue (taPVAT) of the Dahl-SS rat, an important hypertension model. We show that mechanotransducers are widely expressed in these cells. Moreover, PIEZO1 expression is shown to be restricted to the taPVAT and is functionally implicated in stress relaxation. These data will serve as the foundation for future studies investigating the role of taPVAT in this model of hypertensive disease. [ABSTRACT FROM AUTHOR]

Background Many hypertension therapeutics were developed prior to major advances in drug receptor theory. Moreover, newer drugs may take advantage of some of the newly understood modalities of receptor function. Goal The goal of this review is to provide an up-to-date summary of drug receptor theory. This is followed by a discussion of the drug classes recognized for treating hypertension to which new concepts in receptor theory apply. Results We raise ideas for mechanisms of potential new antihypertensive drugs and whether they may take advantage of new theories in drug–receptor interaction. [ABSTRACT FROM AUTHOR]

Introduction: Tunica media extracellular matrix (ECM) remodeling is well understood to occur in response to elevated blood pressure, unlike the remodeling of other tunicas. We hypothesize that perivascular adipose tissue (PVAT) is responsive to hypertension and remodels as a protective measure. Methods: The adventitia and PVAT of the thoracic aorta were used in measuring ECM genes from 5 pairs of Dahl SS male rats on 8 or 24 weeks of feeding from weaning on a control (10% Kcal fat) or high-fat (HF; 60%) diet. A PCR array of ECM genes was performed with cDNA from adventitia and PVAT after 8 and 24 weeks. A gene regulatory network of the differentially expressed genes (DEGs) (HF 2-fold > con) was created using Cytoscape. Results: After 8 weeks, 29 adventitia but 0 PVAT DEGs were found. By contrast, at 24 weeks, PVAT possessed 47 DEGs while adventitia had 3. Top DEGs at 8 weeks in adventitia were thrombospondin 1 and collagen 8a1. At 24 weeks, thrombospondin 1 was also a top DEG in PVAT. The transcription factor Adarb1 was identified as a regulator of DEGs in 8-week adventitia and 24-week PVAT. Conclusion: These data support that PVAT responds biologically once blood pressure is elevated. [ABSTRACT FROM AUTHOR]

Our laboratory has a vested interest in measuring the location and expression of the 5-hydroxytryptamine (5-HT, serotonin) 7 (5-HT7) receptor in the rat. Determining tissue-specific receptor expression would aid in validating understood and potentially new tissues that support the 5-HT7 receptor-mediated fall in blood pressure, an event we are committed to understand. We contracted with 7TM Antibodies to develop deliberately and rigorously a rat 5-HT7 (r5-HT7) receptor specific antibody. Three antigens, two targeting the third internal loop and one the C terminus, were used in three rabbits to generate antibodies. As a positive control, HEK293(T or AD) cells were transfected with a plasmid for the r5-HT7 receptor also expressing a C terminus 3xFLAG tag. Naïve rat tissues were also used in Western and immunohistochemical analyses. Nine antibodies (3 from three different rabbits) detected a ~ 75 kDa protein absent in homogenates of vector control HEK293T cells. Only antibodies that recognized the C terminus of the 5-HT7 receptor [ERPERSEFVLQNSDH(Abu)GKKGHDT; antibodies 3, 6, and 9] positively and concentration-dependently identified the r5-HT7 receptor expressed in Westerns of transfected HEK293T cells. These same C terminus antibodies also successfully detected the r5-HT7 receptor in immunocytochemical test of the transfected HEK293AD cells, colocalizing with the detected FLAG sequence. In naive tissue, antibody 6 performed the best, identifying specific bands in the brain cortex in Western analysis. These same antibodies produced a more diverse band profile in the vena cava, identifying 6 major proteins. In immunohistochemical experiments, the same C-terminus antibodies, with antibody 3 performing the best, detected the 5-HT7 receptor in rat veins. This deliberate work has given rise to at least three antibodies that can be used with good confidence in r5-HT7 transfected cells, two antibodies that can be used in immunohistochemical analyses of rat tissues and in Westerns of rat brain; we are less confident of the use of these same antibodies in rat veins. [ABSTRACT FROM AUTHOR]

Objective: Serotonin (5‐HT) infusion in vivo causes hypotension and a fall in total peripheral resistance. However, the vascular segment and the receptors that mediate this response remain in question. We hypothesized that 5‐HT7 receptors mediate arteriolar dilation to 5‐HT in skeletal muscle microcirculation. Methods: Cremaster muscles of isoflurane‐anesthetized male Sprague‐Dawley rats were prepared for in vivo microscopy of third‐ and fourth‐order arterioles and superfused with physiological salt solution at 34°C. Quantitative real‐time PCR (RT‐PCR) was applied to pooled samples of first‐ to third‐order cremaster arterioles (2–4 rats/sample) to evaluate 5‐HT7 receptor expression. Results: Topical 5‐HT (1–10 nmols) or the 5‐HT1/7 receptor agonist, 5‐carboxamidotryptamine (10–30 nM), dilated third‐ and fourth‐order arterioles, responses that were abolished by 1 μM SB269970, a selective 5‐HT7 receptor antagonist. In contrast, dilation induced by the muscarinic agonist, methacholine (100 nmols) was not inhibited by SB269970. Serotonin (10 nmols) failed to dilate cremaster arterioles in 5‐HT7 receptor knockout rats whereas arterioles in wild‐type litter mates dilated to 1 nmol 5‐HT, a response blocked by 1 μM SB269970. Quantitative RT‐PCR revealed that cremaster arterioles expressed mRNA for 5‐HT7 receptors. Conclusions: 5‐HT7 receptors mediate dilation of small arterioles in skeletal muscle and likely contribute to 5‐HT‐induced hypotension, in vivo. [ABSTRACT FROM AUTHOR]

The adipokine chemerin may support blood pressure, evidenced by a fall in mean arterial pressure after whole body antisense oligonucleotide (ASO)-mediated knockdown of chemerin protein in rat models of normal and elevated blood pressure. Although the liver is the greatest contributor of circulating chemerin, liver-specific ASOs that abolished hepatic-derived chemerin did not change blood pressure. Thus, other sites must produce the chemerin that supports blood pressure. We hypothesize that the vasculature is a source of chemerin independent of the liver that supports arterial tone. RNAScope, PCR, Western blot analyses, ASOs, isometric contractility, and radiotelemetry were used in the Dahl salt-sensitive (SS) rat (male and female) on a normal diet. Retinoic acid receptor responder 2 (Rarres2) mRNA was detected in the smooth muscle, adventitia, and perivascular adipose tissue of the thoracic aorta. Chemerin protein was detected immunohistochemically in the endothelium, smooth muscle cells, adventitia, and perivascular adipose tissue. Chemerin colocalized with the vascular smooth muscle marker α-actin and the adipocyte marker perilipin. Importantly, chemerin protein in the thoracic aorta was not reduced when liver-derived chemerin was abolished by a liver-specific ASO against chemerin. Chemerin protein was similarly absent in arteries from a newly created global chemerin knockout in Dahl SS rats. Inhibition of the receptor Chemerin1 by the receptor antagonist CCX832 resulted in the loss of vascular tone that supports potential contributions of chemerin by both perivascular adipose tissue and the media. These data suggest that vessel-derived chemerin may support vascular tone locally through constitutive activation of Chemerin1. This posits chemerin as a potential therapeutic target in blood pressure regulation. NEW & NOTEWORTHY Vascular tunicas synthesizing chemerin is a new finding. Vascular chemerin is independent of hepaticderived chemerin. Vasculature from both males and females have resident chemerin. Chemerin1 receptor activity supports vascular tone. [ABSTRACT FROM AUTHOR]