Adrenergic Receptor Research Articles

The sympathetic nervous system drives hyperinflammatory responses to Clostridioides difficile infection

Clostridioides difficile infection (CDI) is a leading cause of hospital-acquired infections in the United States, known for triggering severe disease by hyperactivation of the host response. In this study, we determine the impact of the sympathetic nervous system (SNS) on CDI disease severity. Mouse models of CDI are administered inhibitors of SNS activity prior to CDI. Chemical sympathectomy or pharmacological inhibition of norepinephrine synthesis greatly reduces mortality and disease severity in the CDI model. Pharmacological blockade or genetic ablation of the alpha 2 adrenergic receptor ameliorates intestinal inflammation, disease severity, and mortality rate. These results underscore the role of the SNS and the alpha 2 adrenergic receptor in CDI pathogenesis and suggest that targeting neural systems could be a promising approach to therapy in severe disease.

Vagus nerve stimulation with a small total charge transfer improves motor behavior and reduces neuroinflammation in a mouse model of Parkinson's disease

Parkinson's disease (PD) is a common neurodegenerative disease characterized by the loss of dopaminergic (DA) neurons in the substantia nigra (SN). Conventional treatments are ineffective in reversing disease progression. Recently, the therapeutic and rehabilitation potential of vagus nerve stimulation (VNS) in PD has been explored. However, the underlying mechanisms remain largely unknown. In this study, we investigated the neuroprotective effects of VNS in a lateral lesioned mice model of PD. Excluding controls, experimental mice received cuff electrode implantation on the left vagus nerve and 6-hydroxydopamine administration into the bilateral striatum. After ten days, electrical stimulation was delivered for 11 consecutive days onto PD animals. Behavioral tests were performed after stimulation. The expression of TH, Iba-1, GFAP, adrenergic receptors and cytokines in the SN and striatum was detected by immunofluorescence or western blotting. The activity of noradrenergic neurons in the locus coeruleus (LC) was also measured. Our results suggest that VNS improved behavioral performance in rod rotation, open field tests and pole-climbing tests in PD mice, accompanied by a decrease in the loss of dopaminergic neurons in the SN and increased TH expression in the striatum. Neuroinflammation-related factors, such as GFAP, Iba-1, TNF-α and IL-1β were also suppressed in PD mice after VNS compared to those without treatment. Furthermore, the proportion of c-Fos-positive noradrenergic neurons in the LC increased when animals received VNS. Additionally, the expression of the adrenergic receptor of α1BR was also upregulated after VNS compared to PD mice. In conclusion, VNS has potential as a novel PD therapy for neuroprotective effects, and indicate that activation of norepinephric neurons in LC may plays an important role in VNS treatment for PD.

P17-4 Phenol stimulates tumor proliferation and metastasis through regulating β-3 adrenergic receptor

P17-4 Phenol stimulates tumor proliferation and metastasis through regulating β-3 adrenergic receptor

Physiology and immunology of the adrenergic anti-inflammatory pathway

The adrenergic anti-inflammatory pathway represents a critical intersection between the nervous and immune systems, modulating the body's response to inflammation through the action of catecholamines on adrenergic receptors. This review explored the physiology underlying this pathway, focusing on the mechanisms by which the sympathetic nervous system influences immune function. We delved into the roles of specific adrenergic receptors, primarily the beta-adrenergic receptors, in mediating anti-inflammatory effects, highlighting the involved molecular signaling pathways. Additionally, we examined the immunological implications of adrenergic modulation, discussing how these pathways contributed to the resolution of inflammation and the potential for dysregulation in various disease states. Emerging evidence on the therapeutic potential of targeting the adrenergic anti-inflammatory pathway in conditions such as sepsis, autoimmune diseases, and chronic inflammatory disorders was also reviewed. By integrating current knowledge on the physiology and immunology of this pathway, this review aimed to provide a comprehensive understanding of its role in health and disease, offering insights into future research directions and clinical applications.

The lL-10 Secreted by Memory CD4+ T Cells From the Activation of the β2-Adrenergic Receptor With Nebivolol

This study explores how the β-blocker nebivolol inhibits pro-inflammatory IL-17, potentially through the Th17/Treg balance theory (Gonczi et al., 2017, 2021, 2023; Lee, 2018). This theory suggests that inflammatory and anti-inflammatory responses balance each other to maintain good health (Lee, 2018). Increased anti-inflammatory IL-10 secretion may play a role in this regulatory process (Gonczi et al., 2017; Lee, 2018). Peripheral blood mononuclear cells (PBMCs) were isolated from healthy participants, and memory CD4+T cells were purified. Cells were cultured under various conditions, including activation with antibody multicomplex and nebivolol treatment, followed by enzyme-linked immunofluorescent assay (ELISA) to measure IL-10 secretion levels. The data indicate that nebivolol treatment did not result in a significant increase in IL-10 secretion compared to activated controls, suggesting alternative pathways for nebivolol’s effect on IL-17A inhibition in T cells beyond IL-10 regulation. Limitations include variability in Treg proportions in memory CD4+ T cells and incubation time differences for peak IL-10 secretion. Future research should implement flow cytometry for Treg identification and refine IL-10 secretion protocols specific to Tregs to enhance understanding of immune regulation and potential therapeutic applications.

Adenosine 2A Receptors Link Astrocytic Alpha-1 Adrenergic Signaling to Wake-Promoting Dopamine Neurons

BACKGROUNDSleep and arousal disorders are common, but the underlying physiology of wakefulness is not fully understood. The locus coeruleus promotes arousal via alpha-1 adrenergic receptor (α1AR) driven recruitment of wake-promoting dopamine (DA) neurons in the ventral periaqueductal gray (vPAGDA neurons). α1AR expression is enriched on vPAG astrocytes, and chemogenetic activation of astrocytic Gq signaling promotes wakefulness. Astrocytes can release extracellular "gliotransmitters," such as ATP and adenosine, but the mechanism underlying how vPAG astrocytic α1ARs influence sleep/wake behavior and vPAGDA neuron physiology is unknown. METHODSIn this study, we utilized genetic manipulations with ex vivo calcium imaging in vPAGDA neurons and astrocytes, patch-clamp electrophysiology, and behavioral experiments in mice to probe our hypothesis that astrocytic α1ARs mediate noradrenergic modulation of wake-promoting vPAGDA neurons via adenosine signaling. RESULTSActivation of α1ARs with phenylephrine increased calcium transients in vPAGDA neurons and vPAG astrocytes, and increased vPAGDA neuron excitability ex vivo. Chemogenetic Gq-DREADD activation of vPAG astrocytes similarly increased vPAGDA neuron calcium activity and intrinsic excitability. Conversely, shRNA knockdown of vPAG astrocytic α1ARs reduced the excitatory effect of phenylephrine on vPAGDA neurons and blunted arousal during the wake phase. Pharmacological blockade of adenosine 2A (A2A) receptors precludes the α1AR-induced increase in vPAGDA calcium activity and excitability in brain slices, as well as the wake-promoting effects of vPAG α1AR activation in vivo. CONCLUSIONSWe have identified a crucial role for vPAG astrocytic α1AR receptors in sustaining arousal through heightened excitability and activity of vPAGDA neurons mediated by local A2A receptors.

Chronic stimulation desensitizes β2-adrenergic receptor responses in natural killer cells.

Adrenergic receptors (ARs) are preferentially expressed by innate lymphocytes such as natural killer (NK) cells. Here, we study the effect of epinephrine-mediated stimulation of the β2-adrenergic receptor (β2AR) on the function of human NK cells. Epinephrine stimulation inhibited early NK cell signaling events and blocked the function of the integrin LFA-1. This reduced the adhesion of NK cells to ICAM-1, explaining how NK cells are mobilized into the peripheral blood upon epinephrine release during acute stress or exercise. Additionally, epinephrine stimulation transiently reduced NK cell degranulation, serial killing, and cytokine production and affected metabolic changes upon NK cell activation via the cAMP-protein kinase A (PKA) pathway. Repeated exposure to β2AR agonists resulted in the desensitization of the β2AR via a PKA feedback loop-initiated G-protein switch. Therefore, acute epinephrine stimulation of chronically β2AR stimulated NK cells no longer resulted in inhibited signaling and reduced LFA-1 activity. Sustained stimulation by long-acting β2-agonists (LABA) not only inhibited NK cell functions but also resulted in desensitization of the β2AR. However, peripheral NK cells from LABA-treated asthma patients still reacted unchanged to epinephrine stimulation, demonstrating that local LABA administration does not result in detectable systemic effects on NK cells.

Effects of systemic oxytocin and beta-3 receptor agonist (CL 316243) treatment on body weight and adiposity in male diet-induced obese rats.

Previous studies have implicated hindbrain oxytocin (OT) receptors in the control of food intake and brown adipose tissue (BAT) thermogenesis. We recently demonstrated that hindbrain [fourth ventricle (4V)] administration of oxytocin (OT) could be used as an adjunct to drugs that directly target beta-3 adrenergic receptors (β3-AR) to elicit weight loss in diet-induced obese (DIO) rodents. What remains unclear is whether systemic OT can be used as an adjunct with the β3-AR agonist, CL 316243, to increase BAT thermogenesis and elicit weight loss in DIO rats. We hypothesized that systemic OT and β3-AR agonist (CL 316243) treatment would produce an additive effect to reduce body weight and adiposity in DIO rats by decreasing food intake and stimulating BAT thermogenesis. To test this hypothesis, we determined the effects of systemic (subcutaneous) infusions of OT (50 nmol/day) or vehicle (VEH) when combined with daily systemic (intraperitoneal) injections of CL 316243 (0.5 mg/kg) or VEH on body weight, adiposity, food intake and brown adipose tissue temperature (T IBAT ). OT and CL 316243 monotherapy decreased body weight by 8.0±0.9% ( P <0.05) and 8.6±0.6% ( P <0.05), respectively, but OT in combination with CL 316243 produced more substantial weight loss (14.9±1.0%; P <0.05) compared to either treatment alone. These effects were associated with decreased adiposity, energy intake and elevated T IBAT during the treatment period. The findings from the current study suggest that the effects of systemic OT and CL 316243 to elicit weight loss are additive and appear to be driven primarily by OT-elicited changes in food intake and CL 316243-elicited increases in BAT thermogenesis.

Pharmacological characterization of alpha adrenoceptor-mediated motor responses in the rat colon.

Inhibitory neuromuscular transmission in the gastrointestinal tract is mediated by intrinsic nitrergic and purinergic neurons. Purines activate G protein-coupled receptor P2Y1 receptors, increasing intracellular Ca2+ that activates small conductance calcium-activated potassium (SKCa) channels. Little is known about the effect of adrenergic receptor activation on intestinal smooth muscle. In vascular tissue, stimulation of α-adrenoceptors causes smooth muscle contraction, while their effect on intestinal tissue is poorly understood. This study aimed to pharmacologically characterize the effect of α-adrenoceptor activation in the rat colon, which shares similar inhibitory pathways to the human colon. Muscle bath experiments were performed with the rat proximal, mid, and distal colon oriented both circularly and longitudinally. The α1-adrenoceptor agonist phenylephrine (PE) (10-8-10-5 M) evoked concentration-dependent relaxations of the intestinal smooth muscle from all regions and orientations. However, in the mid-circular colon at low PE concentrations, a contraction sensitive to 10-5 M phentolamine (non-selective α-adrenoceptor blocker), the neural blocker tetrodotoxin (TTX; 10-6 M), and atropine (10-6 M) was recorded. PE-induced relaxations were insensitive to TTX (10-6 M) and the nonselective β-adrenoceptor blocker propranolol (10-6 M). In contrast, PE-induced relaxations were blocked by phentolamine (10-5 M), prazosin (10-6 M) (α1-adrenoceptor blocker), and RS17053 (10-6 M) (α1A-blocker), but not by yohimbine (10-6 M) (α2-adrenoceptor blocker). Apamin (10-6 M), a SKCa channel blocker, abolished PE-induced relaxations. Contractile responses in the circular muscle of the mid colon could be attributed to α-adrenoceptors located on enteric cholinergic neurons. Stimulation of α1A-adrenoreceptors activates SKCa channels to cause smooth muscle relaxation, which constitutes a signaling pathway that shares similarities with P2Y1 receptors.

Serum CD5L as potential biomarker of thyroid hormone status during pregnancy.

The thyroid hormone (TH) status is routinely assessed by thyrotropin (TSH) and thyroxine (T4). Both biomarkers are mainly regulated by TH receptor beta, whereas many peripheral organs employ the alpha receptor. Serum cluster of differentiation 5-like molecule (CD5L) is a liver-derived protein under control of both TH receptor isoforms. However, clinical data on its relation to TH status are sparse. An additional biomarker of TH status is needed in particular during pregnancy, where the routine biomarkers become dynamically disturbed. This study aimed to determine possible covariates regulating serum CD5L and to test its potential suitability as additional TH biomarker during pregnancy. A sandwich ELISA for serum CD5L was established using newly raised antibodies. Circadian effects and the impact of liver disease on serum CD5L concentrations were assessed. Serum samples from pregnant women with well-characterized TH and trace element status were analyzed, and CD5L concentrations were correlated with other indicators of TH status including TSH, fT4, fT3, copper, and selenium concentrations. The new quantitative assay for CD5L showed high accuracy. Serum CD5L was stable in dilution and refreezing experiments and did not show strong circadian variance or dependency on liver disease. In serum of pregnant women, CD5L correlated positively to fT3, but not to fT4 or TSH. Significant positive correlations of CD5L were observed with serum levels of the TH-responsive trace elements selenium and copper. The data support the potential suitability of serum CD5L as an additional marker of TH status, with potential value for pregnancy and thyroid disease.

In vivo and in silico antihypertensive, anti-inflammatory, and analgesic activities of Vernonia amygdalina Del. leaf extracts

Vernonia amygdalina (VA) leaves contain many potential active ingredients and exhibit diverse pharmacological activities. The antihypertensive, anti-inflammatory, and analgesic effects of VA crude and fraction extracts were carried out using Swiss albino mice models. VAE is considered safe to be administered due to LD50 being greater than 10,000 mg/kg body weight. A dose-dependent increase in antihypertensive, anti-inflammatory, and analgesic activities was observed in both VAE and fractions, similar to the reference drugs. The antihypertensive effect of the VAE 2.0 (2000 mg/kg, SBP: ↓26.05 %, DBP: ↓34.51 %) was nearly equivalent to Captopril (100 mg/kg, SBP: ↓30.28 %, DBP: ↓40.71 %) with no statistically significant difference (p > 0.05). The VAE 1.0 (1000 mg/kg), and EA 30 (30 mg/kg) showed potent anti-inflammatory activity when reducing the total edematous paw volume significantly (p < 0.01) by ↓65.58 %, and ↓69.34 %, respectively, similar to Ibuprofen (7.5 mg/kg, ↓67.03 %). Besides, VAE (>500 mg/kg), and W 400 (water, 400 mg/kg) fraction extracts showed a potent analgesic effect equivalent to Para 50 (paracetamol 50 mg/kg) for the highest protection (>65 %) against the acetic acid-induced writhing after 35 min. Moreover, cepharanthine, cynaroside, and vernoniosides of VA leaf extract exhibited the highest affinity (>10 kcal/mol) in anti-inflammatory and analgesic targets (iNOS and COX-2) and antihypertensive targets (ACE and β1 adrenoreceptor). Therefore, the crude and fraction extracts of VA leaves from the percolation method and bioactive metabolites are a potential source that can be developed into antihypertensive, anti-inflammatory, and analgesic agents in herbal medicine.

Impact of Tumoral β2-Adrenergic Receptor Expression on Chemotherapeutic Response and Prognosis in Patients with Advanced Colorectal Cancer.

The β2-adrenergic receptor (β2-AR) is a therapeutic target for circulatory agonists and exhibits oncogenic activity in several cancers. However, its role in advanced colorectal cancer (CRC) treated using chemotherapy remains unclear. We investigated the potential of β2-AR as a novel chemosensitivity marker and therapeutic target in inoperable CRC. β2-AR expression was evaluated immunohistochemically in 80 advanced or recurrent CRC cases for which untreated resected specimens were available before systemic chemotherapy implementation. We assessed the relationship among β2-AR protein expression, clinicopathological factors, therapeutic response, and prognosis. Furthermore, we evaluated the significance of β2-AR as an in vitro and in vivo therapeutic target using CRC cell lines and a CRC xenograft model treated with the β-blocker, propranolol, and other anticancer agents. High tumoral β2-AR expression was associated with shorter progression-free survival and chemotherapeutic resistance in patients treated with oxaliplatin-based regimens and bevacizumab-based regimens. We found no synergistic effect between propranolol and oxaliplatin. However, combined administration of propranolol and bevacizumab induced significant tumor shrinkage in the CRC xenograft model. β2-AR is a possible biomarker for chemosensitivity and prognosis in advanced CRC. Repositioning existing β-blockers could be beneficial for treating CRC resistant to existing treatment regimens.

Leveraging adrenergic receptor blockade for enhanced nonalcoholic fatty liver disease treatment via a biomimetic nanoplatform

Nonalcoholic fatty liver disease (NAFLD) is characterized by excessive lipid accumulation, steatosis and fibrosis. Sympathetic nerves play a critical role in maintaining hepatic lipid homeostasis and regulating fibrotic progression through adrenergic receptors expressed by hepatocytes and hepatic stellate cells; however, the use of sympathetic nerve-focused strategies for the treatment of NAFLD is still in the infancy. Herein, a biomimetic nanoplatform with ROS-responsive and ROS-scavenging properties was developed for the codelivery of retinoic acid (RA) and the adrenoceptor antagonist labetalol (LA). The nanoplatform exhibited improved accumulation and sufficient drug release in the fibrotic liver, thereby achieving precise codelivery of drugs. Integration of adrenergic blockade effectively interrupted the vicious cycle of sympathetic nerves with hepatic stellate cells (HSCs) and hepatocytes, which not only combined with RA to restore HSCs to a quiescent state but also helped to reduce hepatic lipid accumulation. We demonstrated the excellent ability of the biomimetic nanoplatform to ameliorate liver inflammation, fibrosis and steatosis. Our work highlights the tremendous potential of a sympathetic nerve-focused strategy for the management of NAFLD and provides a promising nanoplatform for the treatment of NAFLD.

Association of β1- and β2-Adrenergic Receptor Gene Polymorphisms with the Effectiveness of Bisoprolol and Carvedilol in Patients with Heart Failure of Ischemic Etiology

The aim. To study the relationship between β1-, β2-adrenergic receptor (β-AR) gene polymorphisms and the effectiveness of bisoprolol and carvedilol in patients with heart failure (HF) and coronary heart disease. Materials and methods. We examined 201 patients with HF on the background of post-infarction cardiosclerosis. Control group included 43 healthy individuals of comparable age and sex. Genotyping was carried out for 3 polymorphisms (rs1801253 and rs1801252 of the β1-AR gene; rs1042714 of the β2-AR gene). The patients were divided into 2 groups: the first group included 104 (51.7%) patients who took bisoprolol during the year of observation; 97 (48.3%) patients of the second group were treated with carvedilol. Statistical analysis was performed using Statistica 10.0 and SNPStats programs. Results. In patients with HF, the mutant C-allele (rs1801253 polymorphism) of the β1-AR gene was associated with a decrease in the probability of heart rate reduction &gt;15 min-1 against the background of the use of β-blocker during the year (odds ratio [OR] = 0.42 [0.16-0.98], p = 0.041, recessive inheritance model; OR = 0.62 [0.40-0.97], p = 0.038; log-additive inheritance model). The probability of positive dynamics of the left ventricular ejection fraction (LVEF) increased in carriers of the wild A-allele of the rs1801252 (Ser49Gly) polymorphism of the β1-AR gene (OR = 4.86 [2.35-10.08], p &lt; 0.0001, codominant model; OR = 5.18 [2.51-10.68], p &lt; 0.0001, dominant model; OR = 4.68 [2.26-9.68], p &lt; 0.0001, over-dominant model; OR = 5.05 [2.48-10.28], p &lt; 0.0001, log-additive inheritance model). The probability of an increase in LVEF within a year increased with treatment with carvedilol in homozygous mutant G/G rs1042714 polymorphism (Gln27Glu) of the β2-AR gene in patients with HF (OR = 6.09 [1.16-31.88], p = 0.038, dominant inheritance model). Conclusions. Patients with HF of ischemic etiology, carriers of the mutant C-allele of rs1801253 polymorphism of the β1-adrenoceptor gene, are worse responders to the use of β-blockers compared to patients with the wild G-allele (a lower proportion of patients with a decrease in heart rate &gt;15 min-1: 6.8% vs. 14.5%, respectively; OR = 0.42 [0.16-0.98], p = 0.041). The frequency of an increase in the value of the LVEF &gt;10% was higher compared to patients with the mutant G-allele (39.3% vs. 11.1%, respectively; OR = 4.86 [2.35-10.08], p &lt; 0.0001) against the background of application of β-blockers. The use of carvedilol was more appropriate in homozygous carriers of the mutant G-allele of the rs1042714 polymorphism (Gln27Glu) of the β2-AR gene compared to bisoprolol (a greater proportion of patients with an increase in the LVEF: 17.6% vs. 9.1%, respectively; OR = 6.09 [1.16-31.88], p = 0.038). No probable associations of rs1801253 and rs1801252 polymorphisms of the β1-AR gene with the pharmacodynamics of bisoprolol and carvedilol in patients with HF of ischemic etiology were found.

Subcellular activation of β-adrenergic receptors using a spatially restricted antagonist

Gprotein-coupled receptors (GPCRs) regulate several physiological and pathological processes and represent the target of approximately 30% of Food and Drug Administration-approved drugs. GPCR-mediated signaling was thought to occur exclusively at the plasma membrane. However, recent studies have unveiled their presence and function at subcellular membrane compartments. There is a growing interest in studying compartmentalized signaling of GPCRs. This requires development of tools to separate GPCR signaling at the plasma membrane from the ones initiated at intracellular compartments. We leveraged the structural and pharmacological information available for β-adrenergic receptors (βARs) and focused on β1AR as exemplary GPCR that functions at subcellular compartments, and rationally designed spatially restricted antagonists. We generated a cell-impermeable βAR antagonist by conjugating a suitable pharmacophore to a sulfonate-containing fluorophore. This cell-impermeable antagonist only inhibited β1AR on the plasma membrane. In contrast, a cell-permeable βAR antagonist containing a nonsulfonated fluorophore efficiently inhibited both the plasma membrane and Golgi pools of β1ARs. Furthermore, the cell-impermeable antagonist selectively inhibited the phosphorylation of PKA downstream effectors near the plasma membrane, which regulate sarcoplasmic reticulum (SR) Ca2+ release in adult cardiomyocytes, while the β1AR Golgi pool remained active. Our tools offer promising avenues for investigating compartmentalized βAR signaling in various contexts, potentially advancing our understanding of βAR-mediated cellular responses in health and disease. They also offer a general strategy to study compartmentalized signaling for other GPCRs in various biological systems.

Phenylephrine Enhances the Mitogenic Effect of S-Allyl-L-cysteine on Primary Cultured Hepatocytes through Protein Kinase C-Induced B-Raf Phosphorylation.

The co-mitogenic effects of the α1-adrenoceptor agonist phenylephrine on S-allyl-L-cysteine (SAC)-induced hepatocyte proliferation were examined in primary cultures of adult rat hepatocytes. The combination of phenylephrine (10-10-10-6 M) and SAC (10-6 M) exhibited a significant dose-dependent increase in the number of hepatocyte nuclei and viable cells compared to SAC alone. This combination also increased the progression of hepatocyte nuclei into the S-phase. The potentiating effect of phenylephrine on SAC-induced cell proliferation was counteracted by prazosin (an α1-adrenergic receptor antagonist) and GF109203X (selective protein kinase C (PKC) inhibitor). In addition, PMA (direct PKC activator) potentiated the proliferative effects of SAC similarly to phenylephrine. In essence, these findings suggest that PKC activity plays a crucial role in enhancing SAC-induced cell proliferation. Moreover, the effects of phenylephrine on SAC-induced Ras activity, Raf phosphorylation, and extracellular signal-regulated kinase 2 (ERK2) phosphorylation were investigated. Phenylephrine (or PMA) in combination with SAC did not augment Ras activity, but further increased ERK2 phosphorylation and its upstream B-Raf phosphorylation. These results indicate that PKC activation, triggered by stimulating adrenergic α1 receptors, further amplifies SAC-induced cell proliferation through enhanced ERK2 phosphorylation via increased B-Raf-specific phosphorylation in primary cultured hepatocytes.

Blocking α1 Adrenergic Receptor as a Novel Target for Treating Alzheimer's Disease.

While amyloidopathy and tauopathy have been recognized as hallmarks in Alzheimer's disease (AD) brain, recently, increasing lines of evidence have supported the pathological roles of cerebrovascular changes in the pathogenesis and progression of AD. Restoring or ameliorating the impaired cerebrovascular function during the early phase of the disease may yield benefits against the cognitive decline in AD. In the present study, we evaluated the potential therapeutic effects of nicergoline [NG, a well-known α1 adrenergic receptor (ADR) blocker and vasodilator] against AD through ameliorating vascular abnormalities. Our in vitro data revealed that NG could reverse β-amyloid1-42 (Aβ1-42)-induced PKC/ERK1/2 activation, the downstream pathway of α1-ADR activation, in α1-ADR-overexpressed N2a cells. NG also blocked Aβ1-42- or phenylephrine-induced constrictions in isolated rat arteries. All these in vitro data may suggest ADR-dependent impacts of Aβ on vascular function and the reversal effect of NG. In addition, the ameliorating impacts of NG treatment on cerebral vasoconstriction, vasoremodeling, and cognitive decline were investigated in vivo in a PSAPP transgenic AD mouse model. Consistent with in vitro findings, the chronic treatment of NG significantly ameliorated the cerebrovascular dysfunctions and Aβ plaque depositions in the brain. Moreover, an improved cognitive performance was also observed. Taken together, our findings supported the beneficial effects of NG on AD through adrenergic-related mechanisms and highlighted the therapeutic potential of α1-adrenergic vasomodulators against AD pathologies.

Chromogranin B Protects Human Umbilical Endothelial Cells against Oxidative Stress

Chromogranin B (CgB) is involved in the control of the cardiovascular system through the regulation of catecholamine release. Whether CgB can exert direct actions on the endothelium has not yet been clarified. Here, we aimed to investigate the effects of CgB on cell viability, mitochondrial membrane potential, reactive oxygen species (ROS), glutathione (GSH), nitric oxide (NO) release, and the cytosolic calcium concentration ([Ca2+]c) in human vascular endothelial cells (HUVECs) cultured under both physiological and peroxidative conditions. In HUVECs, experiments were conducted to establish the proper concentration and timing of CgB stimulation. Thereafter, specific assays were used to evaluate the response of HUVECs cultured in physiologic or oxidative stress conditions to CgB in the presence or absence of β-adrenergic receptor agonists and antagonists and intracellular pathways blockers. Analysis of cell viability, mitochondrial membrane potential, and NO release revealed that CgB was able to cause increased effects in HUVECs cultured in physiological conditions. Additionally, the same analyses performed in HUVECs cultured with H2O2, showed protective effects exerted by CgB, which was also able to counteract ROS release and maintain GSH levels. Furthermore, CgB played a dual role on the [Ca2+]c depending on the physiological or peroxidative cell culturing conditions. In conclusion, our data provide new information about the direct role of CgB in the physiological regulation of endothelial function and highlight its potential as a protective agent against peroxidative conditions, such as those found in cardiovascular diseases.

Advancing Glaucoma Therapy by Exploring the Efficacy and Potential of Brimonidine Niosomal Gel

Glaucoma is a leading cause of permanent vision loss worldwide and is characterised by progressive optic neuropathy with elevated intraocular pressure (IOP) as a major risk factor. Although successful, the current therapeutic strategies are often severely limited by their need for chronic dosing, systemic side effects and poor patient compliance. Brimonidine, an alpha-2 adrenergic receptor agonist which acts selectively, has been beneficial through its IOP-lowering effects by diminishing aqueous humor production and improving uveoscleral outflow. A novel medication delivery technology to enhance ocular bioavailability and extended drug release is brimonidine, formulated as a niosomal gel. The aim of this study is to highlight its clinical efficacy, formulation strategies and mechanism of action that significantly improved glaucoma therapy. Key studies illuminate its potential benefits in reducing dosing frequency, avoiding side effects and increasing patient compliance. Additional study and optimization required to scale-up manufacturing or ensure long-term stability. Possible future directions: combination medications and delivery systems personalized medicine possible future directions in the treatment of glaucoma might include combination medicines and personalized medicine techniques tailored to patient-specific needs. Brimonidine niosomal gel may be a new approach for glaucoma management and it can change the concept of intraocular drug delivery in the future.

Update on the Role of β2AR and TRPV1 in Respiratory Diseases.

Respiratory diseases (RDs) constitute a common public health problem both in industrialized and developing countries. The comprehension of the pathophysiological mechanisms underlying these conditions and the development of new therapeutic strategies are critical for improving the quality of life of affected patients. β2-adrenergic receptor (β2AR) and transient receptor potential vanilloid 1 (TRPV1) are both involved in physiological responses in the airways. β2AR is implicated in bronchodilation, mucociliary clearance, and anti-inflammatory effects, while TRPV1 is involved in the mediation of pain and cough reflexes. In RDs, such as respiratory infections, asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis, the concentration and expression of these receptors can be altered, leading to significant consequences. In this review, we provided an update on the literature about the role of β2AR and TRPV1 in these conditions. We reported how the diminished or defective expression of β2AR during viral infections or prolonged therapy with β2-agonists can increase the severity of these pathologies and impact the prognosis. Conversely, the role of TRPV1 was pivotal in neuroinflammation, and its modulation could lead to innovative treatment strategies in specific patients. We indicate future perspectives and potential personalized treatments in RDs through a comprehensive analysis of the roles of these receptors in the physiological and pathological mechanisms of these pathologies.