Browsing by Author "Wean, Sarah"

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    Cytokine-induced F-actin reorganization in endothelial cells involves RhoA activation
    (2009-03) Campos, Silvia B; Ashworth, Sharon L; Wean, Sarah; Hosford, Melanie; Sandoval, Ruben M; Hallett, Mark A; Atkinson, Simon J; Molitoris, Bruce A
    Acute ischemic kidney injury results in marked increases in local and systemic cytokine levels. IL-1α, IL-6, and TNF-α orchestrate various inflammatory reactions influencing endothelial permeability by altering cell-to-cell and cell-to-extracellular matrix attachments. To explore the role of actin and the regulatory proteins RhoA and cofilin in this process, microvascular endothelial cells (MS1) were exposed to individual cytokines or a cytokine cocktail. Within minutes, a marked, time-dependent redistribution of the actin cytoskeleton occurred with the formation of long, dense F-actin basal stress fibers. The concentration of F-actin, normalized to nuclear staining, significantly increased compared with untreated cells (up 20%, P ≤ 0.05). Western blot analysis of MS1 lysates incubated with the cytokine cocktail for 4 h showed an increase in phosphorylated/inactive cofilin (up 25 ± 15%, P ≤ 0.05) and RhoA activation (up to 227 ± 26% increase, P ≤ 0.05) compared with untreated cells. Decreasing RhoA levels using small interfering RNA blocked the effect of cytokines on stress fiber organization. Treatment with Y-27632, an inhibitor of the RhoA effector p160-ROCK, decreased levels of phosphorylated cofilin and reduced stress fiber fluorescence by 22%. In cells treated with Y-27632 followed by treatment with the cytokine cocktail, stress fiber levels were similar to control cells and cofilin phosphorylation was 55% of control levels. Taken together, these studies demonstrate cytokine stimulation of RhoA, which in turn leads to cofilin phosphorylation and formation of numerous basal actin stress fibers. These results suggest cytokines signal through the Rho-ROCK pathway, but also through another pathway to affect actin dynamics.
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    Neural Activity in the Anterior Insula at Drinking Onset and Licking Relates to Compulsion-Like Alcohol Consumption
    (Society for Neuroscience, 2024-02-28) Starski, Phillip; Morningstar, Mitch D.; Katner, Simon N.; Frasier, Raizel M.; De Oliveira Sergio, Thatiane; Wean, Sarah; Lapish, Christopher C.; Hopf, F. Woodward; Psychiatry, School of Medicine
    Much remains unknown about the etiology of compulsion-like alcohol drinking, where consumption persists despite adverse consequences. The role of the anterior insula (AIC) in emotion, motivation, and interoception makes this brain region a likely candidate to drive challenge-resistant behavior, including compulsive drinking. Indeed, subcortical projections from the AIC promote compulsion-like intake in rats and are recruited in heavy-drinking humans during compulsion for alcohol, highlighting the importance of and need for more information about AIC activity patterns that support aversion-resistant responding. Single-unit activity was recorded in the AIC from 15 male rats during alcohol-only and compulsion-like consumption. We found three sustained firing phenotypes, sustained-increase, sustained-decrease, and drinking-onset cells, as well as several firing patterns synchronized with licking. While many AIC neurons had session-long activity changes, only neurons with firing increases at drinking onset had greater activity under compulsion-like conditions. Further, only cells with persistent firing increases maintained activity during pauses in licking, suggesting roles in maintaining drive for alcohol during breaks. AIC firing was not elevated during saccharin drinking, similar to lack of effect of AIC inhibition on sweet fluid intake in many studies. In addition, we observed subsecond changes in AIC neural activity tightly entrained to licking. One lick-synched firing pattern (determined for all licks in a session) predicted compulsion-like drinking, while a separate lick-associated pattern correlated with greater consumption across alcohol intake conditions. Collectively, these data provide a more integrated model for the role of AIC firing in compulsion-like drinking, with important relevance for how the AIC promotes sustained motivated responding more generally.
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    The role of beta- and alpha-adrenergic receptors on alcohol drinking
    (Elsevier, 2023) De Oliveira Sergio, Thatiane; Wean, Sarah; Katner, Simon Nicholas; Hopf, Frederic W.; Psychiatry, School of Medicine
    Alcohol Use Disorders (AUD) is characterized by compulsion-like alcohol drinking (CLAD), where intake despite negative consequences can be a major clinical obstacle. With few treatment options available for AUD, there is a significant need for novel therapies. The noradrenergic system is an important hub for regulating stress responses and maladaptive drives for alcohol. Studies have shown that drugs targeting α1 adrenenergic receptors (ARs) may represent a pharmacological treatment for pathological drinking. However, the involvement of β ARs for treating human drinking has received scant investigation, and thus we sought to provide pre-clinical validation for possible AR utility for CLAD by analyzing whether β AR antagonists propranolol (β1/2), betaxolol (β1), and ICI, 118,551 (β2) impacted CLAD and alcohol-only drinking (AOD) in male Wistar rats. We found that the highest dose of propranolol tested systemically (10 mg/kg) reduced alcohol drinking, while 5 mg/kg propranolol reduced drinking with a trend to impact CLAD more than AOD, and with no effects of 2.5 mg/kg. Betaxolol (2.5 mg/kg) also decreased drinking, while ICI 118.551 had no effects. Also, while AR compounds might have utility for AUD, they can also lead to undesirable side effects. Here, a combination of ineffective doses of propranolol and prazosin reduced both CLAD and AOD. Finally, we investigated the effect of propranolol and betaxolol in two brain areas related to pathological drinking, the anterior insula (aINS) and medial prefrontal cortex (mPFC). Surprisingly, propranolol (1-10 μg) in aINS or mPFC did not affect CLAD or AOD. Together, our findings provide new pharmacological insights into noradrenergic regulation of alcohol consumption, which may inform AUD therapy.
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    α1 Adrenergic Receptors Mediate Panic-like Defensive Behavior in Alcohol-Drinking but Not Alcohol-Naïve Rats
    (MDPI, 2025-03-28) De Oliveira Sergio, Thatiane; Kellner, Jacob; Wean, Sarah; Hopf, Frederic W.; Psychiatry, School of Medicine
    Background: Most animals display different defensive behavioral strategies during imminent or potential threats. These responses are relevant for understanding human behavioral disorders. In addition, α1 adrenergic receptors (α1ARs) are blocked by prazosin and regulate a diverse set of behaviors, including alcohol drinking related to anxiety in humans, alcohol intake in rats, responses to strong acute stresses (like restraint), and several forms of cognitive flexibility. However, the role of α1ARs in regulating panic-like escape behavior remains unexplored. Methods: Male and female Wistar rats were chronic alcohol drinkers and age-matched alcohol naïves. Animals received an injection of 0.75 mg/kg of prazosin or vehicle and then were exposed to the elevated T maze (ETM) to evaluate avoidance and escape behavior. One week later, animals underwent the light-dark test (LDT) and open field test. Results: α1AR inhibition with prazosin increased latency for escape in male and female alcohol drinkers, with no significant effects in alcohol-naïve controls. There were also interesting impacts from alcohol drinking, including a decrease in ETM avoidance in female but not male drinkers. In addition, prazosin increased latency to enter the dark in LDT in female drinkers and male naïves. Although prazosin also decreased the number of transitions in males, no differences were found in open-field locomotion. Conclusions: These results suggest that α1ARs mediate escape-like behavior in male and female alcohol drinkers, shedding light on a novel therapy for alcohol problems related to panic and anxiety.