Explore the vast range of titles available.

Monocyte-derived macrophages (MDMs) are key players in tissue homeostasis and diseases regulated by a variety of signaling molecules. Recent literature has highlighted the ability for biogenic amines to regulate macrophage functions, but the mechanisms governing biogenic amine signaling in and around immune cells remain nebulous. In the CNS, biogenic amine transporters are regarded as the master regulators of neurotransmitter signaling. While we and others have shown that macrophages express these transporters, relatively little is known of their function in these cells. To address these knowledge gaps, we investigated the function of norepinephrine transporter (NET) and dopamine transporter (DAT) on human MDMs. We found that both NET and DAT are present and can uptake substrate from the extracellular space at baseline. Not only was DAT expressed in cultured MDMs, but it was also detected in a subset of intestinal macrophages in situ. Surprisingly, we discovered a NET-independent, DAT-mediated immunomodulatory mechanism in response to LPS. LPS induced reverse transport of dopamine through DAT, engaging an autocrine/paracrine signaling loop that regulated the macrophage response. Removing this signaling loop enhanced the proinflammatory response to LPS. Our data introduce a potential role for DAT in the regulation of innate immunity.

Monocyte-derived macrophages are key players in tissue homeostasis and disease regulated by a variety of signaling molecules. Recent literature has highlighted the ability for biogenic amines to regulate macrophage functions, but the mechanisms governing biogenic amine signaling on and around immune cells remains nebulous. In the central nervous system, biogenic amine transporters are regarded as the master regulators of neurotransmitter signaling. While we and others have shown macrophages express these transporters, relatively little is known of their function on these cells. To address these knowledge gaps, we interrogated the function of norepinephrine (NET) and dopamine (DAT) transporters on human monocyte-derived macrophages. We found that both NET and DAT are present and can uptake substrate from the extracellular space at baseline. Not only was DAT expressed in cultured macrophages, but it was also detected in a subset of intestinal macrophages in situ. Surprisingly, we discovered a NET-independent, DAT-mediated immuno-modulatory mechanism in response to lipopolysaccharide (LPS). LPS induced reverse transport of dopamine through DAT, engaging autocrine/paracrine signaling loop that regulated the macrophage response. Removing this signaling loop enhanced the pro-inflammatory response to LPS. Finally, we found that this DAT-immune axis was disrupted in disease. Collectively, our data introduce a novel role for DAT in the regulation of innate immunity during health and disease. Competing Interest Statement The authors have declared no competing interest.

Background Hypertension is the most important modifiable risk factor for cardiovascular disease, the leading cause of mortality in the United States. The Emergency Department represents an underutilized opportunity to impact difficult-to-reach populations. There are 136 million visits to the Emergency Department each year and nearly all have at least one blood pressure measured and recorded. Additionally, an increasing number of African Americans and socioeconomically disadvantaged patients are overrepresented in the Emergency Department patient population. In the age of electronic health records and mobile health, the Emergency Department has the potential to become an integral partner in chronic disease management. The electronic health records in conjunction with mobile health behavior interventions can be leveraged to identify hypertensive patients to impact otherwise unreached populations. Methods Reach Out is a factorial trial studying multicomponent, behavioral interventions to reduce blood pressure in the Emergency Department patient population. Potential participants are identified by automated alerts from the electronic health record and, following consent, receive a blood pressure cuff to take home. During the initial screening phase, they are prompted to submit weekly blood pressure readings. Responders with persistent hypertension are then randomized into one of three component arms, consisting of varying intensity levels: (1) healthy behavior text messaging (daily vs. none), (2) blood pressure self-monitoring (daily vs. weekly), and (3) facilitated primary care provider appointment scheduling and transportation (yes vs. no). If participants are randomized to receive facilitated primary care provider appointment scheduling and are not established with a primary care provider, care will be established at a local Federally Qualified Health Center. Participants are followed for 12 months. Discussion The Reach Out study is designed to determine which behavioral intervention components or ‘dose’ of components contributes to a reduction in systolic blood pressure after 1 year (Aim 1). The study will also assess the effect of primary care provider appointment assistance on total primary care follow-up visits of hypertensive patients treated in an urban, safety net Emergency Department (Aim 2). Ideally, the Reach Out system will contribute to hypertension management, serving as a model for safety net hospitals and Federally Qualified Health Centers to improve chronic disease management in underserved communities. Trial registration This study was registered at clinicaltrials.gov, identifier NCT03422718 . The record was first available to the public on January 30, 2018 prior to the enrollment of patients on March 25, 2019.