The effects of 5HT3 receptor antagonist granisetron on inflammatory parameters and angiogenesis in the air-pouch model of inflammation

Unraveling the Interplay of 5-hydroxytryptamine-3 and N-methyl-d-aspartate Receptors in Seizure Susceptibility

BACKGROUND

Epilepsy, a prevalent neurological disorder characterized by recurrent seizures, presents significant challenges in treatment and management. This study aimed to evaluate the effect of tropisetron, a selective 5-HT3 receptor antagonist on pentylenetetrazole (PTZ) - induced seizure in mice by exploring the potential role of the NMDA receptor and inflammatory responses.

METHODS

For this purpose, seizures were induced by intravenous PTZ infusion. Tropisetron at 1-, 2-, 3-, 5-, 10- mg/kg were administered intraperitoneally 30 minutes before PTZ. To evaluate probable role of NMDA signaling, selective NMDAR antagonists, ketamine and MK-801, were injected 15 minutes before tropisetron. Also, TNF-α level of hippocampus were measured following administration of mentioned drugs in mice.

RESULTS

Our results demonstrate that tropisetron displayed a dose-dependent impact on seizure threshold, with certain doses (5 and 10 mg/kg) exhibiting anticonvulsant properties. In addition, the noncompetitive NMDAR antagonists, ketamine (1 mg/kg) and MK-801 (0.5 mg/kg), at doses that had no effect on seizure threshold, augmented the anticonvulsant effect of tropisetron (3 mg/kg). Also, tropisetron led to a reduction in hippocampal TNF-α levels, indicating its anti-inflammatory potential independent of 5-HT receptor activity.

CONCLUSION

In conclusion, we demonstrated that the anticonvulsant effect of tropisetron is mediated by the inhibition of NMDA receptors and a decline in hippocampal TNF-α level. These findings highlight a potential connection between 5-HT3 and NMDA receptors in the pharmacological treatment of inflammatory diseases, such as seizure, warranting further investigation into their combined therapeutic effects.

Ultrasound-assisted bromination of indazoles at the C3 position with dibromohydantoin

Bromoaryl compounds have attracted great attention in organic chemistry, especially for the synthesis of pharmaceutical intermediates. Herein, we demonstrated a novel and efficient bromination protocol of indazoles via C-H bond cleavage to give site-specific 3-bromide products that could be further employed as synthetic blocks to prepare drugs. The reaction used DBDMH as a bromine source, tolerated a wide range of indazoles, and finished in 30 min under mild, ultrasound-assisted conditions. Besides, preliminary mechanistic studies revealed that this approach was not a radical process.

The relationship between the serotonergic system and COVID-19 disease: A review

COVID-19 is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which led to a pandemic started in Wuhan, China, in 2019. The rapid spread of the disease in the world, unprecedented mortality rate, and lack of definitive treatment for the disease have led to a global effort to develop effective vaccines as well as new therapeutic interventions. Immune cells activation with excessive inflammation is an important pathophysiological feature of COVID-19 that may impair the various organs functions. Accordingly, these could cause dysfunction in the brain with some symptoms such as respiratory failure, headache, impaired consciousness, olfactory and taste disorders, and severe neurological disorders such as encephalitis. It was found that there is a two-way communication between the immune system and the nervous system through classical neurotransmitters, hormones, and cytokines. Among neurotransmitters, serotonin plays important roles in the immune system and in regulating inflammatory responses by central and peripheral mechanisms. This article aimed to review the two-way relationship between the immune and the nervous systems by focusing on the serotonergic system and the emerging COVID-19 disease.

Granisetron attenuates liver injury and inflammation in a rat model of cecal ligation and puncture-induced sepsis

BACKGROUND AND AIMS

Sepsis induced liver injury is recognized as a serious complication in intensive care units, it is deeply associated with oxidative stress, inflammation and subsequent pyroptosis. Hepatic pyroptosis known to aggravate sepsis-induced liver injury. Previous studies proved that granisetron has anti-inflammatory and antioxidant properties. Accordingly, this study aimed to evaluate the efficacy of granisetron on sepsis-induced liver damage using a cecal ligation and puncture (CLP) model in rats.

MAIN METHODS

Male albino rats were randomly divided into four groups: a sham control group, a granisetron control group, a CLP-induced sepsis group and a granisetron-treated CLP group. Markers of oxidative stress, inflammation, pyroptosis-related proteins and liver function were measured in addition to the histopathological study.

KEY FINDINGS

Granisetron pretreatment significantly decreased mortality and improved liver function, as indicated by decreased ALT, AST, and total bilirubin and increased albumin content. Moreover, granisetron increased GPx activity and downregulated hepatic MDA. Furthermore, granisetron administration significantly reduced TNF-α, IL-6, HMGB1 and NF-κB. It also decreased the expression of receptor for advanced glycation end and TLR4 in the liver tissue. Interestingly, granisetron inhibited pyroptosis as it reduced NLRP3, IL-1β and caspase-1. Granisetron was shown to increase Nrf2 and HO-1. In addition, granisetron treatment repaired, to some extent, the abnormal architecture of hepatic tissue.

SIGNIFICANCE

Our results suggested that granisetron is a potential therapeutic agent for sepsis-associated liver injury, possibly acting by inhibiting oxidative stress, inflammation and subsequent pyroptosis.

Granisetron Alleviates Alzheimer's Disease Pathology in TgSwDI Mice Through Calmodulin-Dependent Protein Kinase II/cAMP-Response Element Binding Protein Pathway

Alzheimer's disease (AD) is characterized by a compromised blood-brain barrier (BBB) and disrupted intracellular calcium homeostasis in the brain. Therefore, rectifying the BBB integrity and restoring calcium homeostasis could provide an effective strategy to treat AD. Recently, we developed a high throughput-screening assay to screen for compounds that enhance a cell-based BBB model integrity, which identified multiple hits among which is granisetron, a Food and Drug Administration approved drug. Here, we evaluated the therapeutic potential of granisetron against AD. Granisetron was tested in C57Bl/6J young and aged wild-type mice, and in a transgenic mouse model of AD namely TgSwDI for its effect on BBB intactness and amyloid-β (Aβ)-related pathology. Our study findings showed that granisetron enhanced BBB integrity in both aged and TgSwDI mice. This effect was associated with an overall reduction in Aβ load and neuroinflammation in TgSwDI mice brains. In addition, and supported by proteomics analysis, granisetron significantly reduced Aβ induced calcium influx in vitro, and rectified calcium dyshomeostasis in TgSwDI mice brains by restoring calmodulin-dependent protein kinase II/cAMP-response element binding protein pathway, which was associated with cognitive improvement. These results support granisetron repurposing as a potential drug to hold, slow, and/or treat AD.

LASSBio-1586, an N-acylhydrazone derivative, attenuates nociceptive behavior and the inflammatory response in mice

Pain and inflammation are complex clinical conditions that are present in a wide variety of disorders. Most drugs used to treat pain and inflammation have potential side effects, which makes it necessary to search for new sources of bioactive molecules. In this paper, we describe the ability of LASSBio-1586, an N-acylhydrazone derivative, to attenuate nociceptive behavior and the inflammatory response in mice. Antinociceptive activity was evaluated through acetic acid-induced writhing and formalin-induced nociception tests. In these experimental models, LASSBio-1586 significantly (p<0.05) reduced nociceptive behavior. Several methods of acute and chronic inflammation induced by different chemical (carrageenan, histamine, croton oil, arachidonic acid) and physical (cotton pellet) agents were used to evaluate the anti-inflammatory effect of LASSBio-1586. LASSBio-1586 exhibited potent anti-inflammatory activity in all tests (p<0.05). Study of the mechanism of action demonstrated the possible involvement of the nitrergic, serotonergic and histamine signaling pathways. In addition, a molecular docking study was performed, indicating that LASSBio-1586 is able to block the COX-2 enzyme, reducing arachidonic acid metabolism and consequently decreasing the production of prostaglandins, which are important inflammatory mediators. In summary, LASSBio-1586 exhibited relevant antinociceptive and anti-inflammatory potential and acted on several targets, making it a candidate for a new multi-target oral anti-inflammatory drug.

Phenylpyridine-2-ylguanidines and rigid mimetics as novel inhibitors of TNFα overproduction: Beneficial action in models of neuropathic pain and of acute lung inflammation

4-phenylpyridin-2-yl-guanidine (5b): a new inhibitor of the overproduction of pro-inflammatory cytokines (TNFα and Il1β) was identified from a high-throughput screening of a chemical library on human peripheral blood mononuclear cells (PBMCs) after LPS stimulation. Derivatives, homologues and rigid mimetics of 5b were designed and synthesized, and their cytotoxicity and ability to inhibit TNFα overproduction were evaluated. Among them, compound 5b and its mimetic 12 (2-aminodihydroquinazoline) showed similar inhibitory activities, and were evaluated in vivo in models of lung inflammation and neuropathic pain in mice. In particular, compound 12 proved to be active (5 mg/kg, ip) in both models.

Pentafluorosulfanyl-Substituted Benzopyran Analogues As New Cyclooxygenase-2 Inhibitors with Excellent Pharmacokinetics and Efficacy in Blocking Inflammation

In this report, we disclose the design and synthesis of a series of pentafluorosulfanyl (SF₅) benzopyran derivatives as novel COX-2 inhibitors with improved pharmacokinetic and pharmacodynamic properties. The pentafluorosulfanyl compounds showed both potency and selectivity for COX-2 and demonstrated efficacy in several murine models of inflammation and pain. More interestingly, one of the compounds, R,S-3a, revealed exceptional efficacy in the adjuvant induced arthritis (AIA) model, achieving an ED₅₀ as low as 0.094 mg/kg. In addition, the pharmacokinetics of compound R,S-3a in rat revealed a half-life in excess of 12 h and plasma drug concentrations well above its IC₉₀ for up to 40 h. When R,S-3a was dosed just two times a week in the AIA model, efficacy was still maintained. Overall, drug R,S-3a and other analogues are suitable candidates that merit further investigation for the treatment of inflammation and pain as well as other diseases where COX-2 and PGE₂ play a role in their etiology.

Granisetron and carvedilol can protect experimental rats againstadjuvant-induced arthritis

CONTEXT

Rheumatoid arthritis (RA), a disabling autoimmune disorder of the joints as well as other organs, affects about 1% of population. Unfortunately, all current treatments of RA cause severe gastrointestinal, renal and other complications.

OBJECTIVE

We aimed to evaluate the possible antiarthritic effects of a serotonin 5-HT₃ receptor blocker, granisetron, and a nonselective adrenergic receptor blocker, carvedilol, on complete Freund's adjuvant-induced RA in adult female albino rats.

MATERIALS AND METHODS

Rats were allocated into a normal control group, an arthritis control group, two reference treatment groups receiving dexamethasone (1.5 mg/kg/day) and methotrexate (1 mg/kg/day), and two treatment groups receiving granisetron (2.5 mg/kg/day) and carvedilol (10 mg/kg/day). Serum-specific rheumatoid, immunological, inflammatory and oxidative stress biomarkers were assessed. A confirmatory histopathological study on joints and spleens was performed.

RESULTS

Granisetron administration significantly improved all the measured biomarkers, with the values of rheumatoid factor, matrix metalloproteinase-3, cartilage oligomeric matrix protein, immunoglobulin G, antinuclear antibody and myeloperoxidase being restored back to normal levels. Carvedilol administration significantly improved all biomarkers, with serum MPO value restored back to normal levels.

DISCUSSION AND CONCLUSIONS

Serotonin 5-HT₃ receptor blockers and adrenergic receptor blockers, represented by granisetron and carvedilol, may represent new promising protective strategies against RA, at least owing to immune-modulator, anti-inflammatory and antioxidant potentials.

Evaluation of 5-HT7 Receptor Trafficking on In Vivo and In Vitro Model of Lipopolysaccharide (LPS)-Induced Inflammatory Cell Injury in Rats and LPS-Treated A549 Cells

This study aimed to investigate the effects of the 5-HT7 receptor agonist (LP44) and antagonist (SB269970) on LPS-induced in vivo tissue damage and cell culture by molecular methods. This study was conducted in two steps. For in vivo studies, 24 female rats were divided into four groups. Group I: healthy; II (2nd h): LPS 5 mg/kg administered intraperitoneally (i.p.); III (4th h): LPS 5 mg/kg administered i.p.; IV (8th h): LPS 5 mg/kg administered i.p. For in vitro studies, we used the A549 cell line. Groups: I control (healthy) (2-4 h); II LPS: 1 µg/ml E. Coli O55:B5 strain (2-4 h); III agonist (LP44) 10^-9 M (2-4 h); IV antagonist (SB269970) 10^-9 M (2-4 h); V LPS+agonist 10^-9 M (LP44 1 µg/ml) (2-4 h); VI LPS+antagonist 10^-9 M (2-4 h). In molecular analyses, we determined increased TNF-α, IL-1β, NF-κB, and 5-HT7 mRNA expressions in rat lung tissues and increased TNF-α, iNOS, and 5-HT7 mRNA expressions in the A549 cell line. In in vitro parameters, LP44 agonist administration-related decrease was observed. Our study showed that lung 5-HT7 receptor expression is increased in LPS-induced endotoxemia. All this data suggest that 5-HT7 receptor overexpression is an important protective mechanism during LPS-induced sepsis-related cell damage.

Mast Cell Serotonin Immunoregulatory Effects Impacting on Neuronal Function: Implications for Neurodegenerative and Psychiatric Disorders

Mast cells (MCs) are derived from hemopoietic precursor cells, undergo their maturation in peripheral tissues, and play a significant role in both the innate and adaptive immune response. Cross-linking of the FcεRI on MCs initiates activation of several cytoplasmic protein tyrosine kinases which rapidly lead to phosphorylation and recruitment of adaptor molecules. These effects trigger the release of preformed mediators stored in the cytoplasmic granules, including histamine, serotonin and tryptase, as well as newly synthesized mediators, such as cytokines/chemokines, prostaglandins, leukotrienes, and growth factors. Serotonin (5-HT) is a bioactive monoamine, which has seven specific cell surface membrane bound receptors which are coupled to G-proteins, plays an important role in the central and peripheral nervous system, and is one of the key mediators in signaling between nervous and immune systems. Serotonin is not stored in all MC types but is implicated in MC adhesion, chemotaxis, tumorigenesis, and tissue regeneration through smooth muscle differentiation of stromal cells. Recent evidence indicates that serotonin has immunoregulatory actions that may be important in neuropsychiatric conditions. Chemokines, RANTES/CCL5, MCP-1/CCL2, and related molecules, constitute the C-C class of chemokine supergene family, play a role in regulating T helper-cell cytokine production and MC trafficking, and are involved in histamine and serotonin generation and MC functions. Pro-inflammatory cytokines such as interleukin-1-β and tumor necrosis factor which mediate MC response, are capable of activating p38 MAPK, and might increase serotonin generation through p38 MAPK activation. Here, we review the relationship between MCs and serotonin and its role in inflammatory diseases and neuroimmune interactions.

Therapeutic action of 5-HT3 receptor antagonists targeting peritoneal macrophages in post-operative ileus

BACKGROUND AND PURPOSE

Post-operative ileus (POI) is induced by intestinal inflammation. Here, we aimed to clarify the effects of 5-HT3 receptor antagonists against POI.

EXPERIMENTAL APPROACH

We administered three 5-HT3 receptor antagonists, ondansetron, tropisetron and palonosetron, to a mouse model of POI induced by surgical intestinal manipulation (IM). Immunohistochemistry, intestinal transit, inflammatory mediator mRNA expression and 5-HT content were measured. In some experiments, 5-HT3 A receptor null mice were used.

KEY RESULTS

Three 5-HT3 receptor antagonists reduced IM-induced infiltration of inflammatory CD68-positive macrophages and myeloperoxidase-stained neutrophils. Ondansetron exhibited no anti-inflammatory actions in 5-HT3 A receptor null mice. Ondansetron inhibited expression of the chemokine CCL2, IL-1β, IL-6, TNF-α and iNOS mRNAs up-regulated by IM, and also ameliorated the delayed gastrointestinal transit. Peritoneal macrophages, but not most infiltrating monocyte-derived macrophages, expressed 5-HT3 receptors. IM stimulation increased the 5-HT content of peritoneal lavage fluid, which up-regulated mRNA expression of proinflammatory cytokines in peritoneal macrophages. Immunohistochemical localization of 5-HT3 receptors suggests that ondansetron suppressed expression of these mRNAs in activated peritoneal macrophages, adhering to the serosal region of the inflamed intestinal wall.

CONCLUSION AND IMPLICATIONS

5-HT3 receptor antagonists were anti-inflammatory, mainly targeting peritoneal macrophages expressing these receptors. They also restored the delayed gastrointestinal transit by IM. 5-HT3 receptor antagonists should be therapeutically useful agents against POI.

Dopamine and serotonin regulate tumor behavior by affecting angiogenesis

The biogenic amines dopamine and serotonin are neurotransmitters and hormones, which are mainly produced in the central nervous system and in the gastro-intestinal tract. They execute local and systemic functions such as intestinal motility and tissue repair. Dopamine and serotonin are primarily stored in and transported by platelets. This review focuses on the recently recognized role of dopamine and serotonin in the regulation of tumor behavior by affecting angiogenesis and tumor cell proliferation. Preclinical studies demonstrate that dopamine inhibits tumor growth via activation of dopamine receptor D2 on endothelial and tumor cells. Serotonin stimulates tumor growth via activation of serotonin receptor 2B on endothelial cells and serotonin receptors on tumor cells. Drugs that stimulate dopamine receptor D2 or inhibit serotonin receptors are available and therefore clinical intervention studies for cancer patients are within reach.

Differential pharmacotherapy for subgroups of fibromyalgia patients with specific consideration of 5-HT3 receptor antagonists

INTRODUCTION

The fibromyalgia syndrome (FMS) has a prevalence of about 2% and is characterized by generalized musculoskeletal pain, reduced pain threshold and autonomic and functional symptoms. It is a multifactorial syndrome with four different subgroups exhibiting pathophysiological and psychiatric findings. No precise treatment strategy is currently available for the different FMS subgroups.

AREAS COVERED

This article reviews the evidence for treatment options for the different FMS subgroups.

EXPERT OPINION

Therapy for the first subgroup of primary FMS, with high levels of pain but no psychopathological alterations, is targeted at nociceptors expressing serotonin (5-hydroxytryptamine-3; 5-HT3) receptors with 5-HT3 receptor antagonists. The second and third subgroups are characterized by depressive syndromes with a major indication for antidepressants. The fourth subgroup with psychosomatic syndromes requires psychotherapeutic treatment. Secondary FMS is similar to the primary syndromes but is triggered by a variety of other diseases and frequently responds to 5-HT3 receptor antagonist treatment. Different classes of drug, such as pregabalin, must be tested for efficacy and tolerance. FMS treatment strategies should be tailored after the identification of individual FMS subgroups. Although several groups of drug have been studied extensively, 5-HT3 receptor antagonists are most effective in patients without psychopathological alterations.