Cyclophosphamide-induced cystitis results in NLRP3-mediated inflammation in the hippocampus and symptoms of depression in rats

D-Pinitol improves cognitive dysfunction and neuronal damage induced by isoproterenol via modulation of NF-κB/BDNF/GFAP signaling in Swiss albino mice

Objectives

Neurological disorders are the world's most distressing problem. The adverse effects of current medications continue to compel scientists to seek safer, more effective, and economically affordable alternatives. In this vein, we explored the effect of D-Pinitol on isoproterenol-induced neurotoxicity in mice.

Materials and Methods

Forty-two mice were randomly distributed into 7 groups each having 6 animals. Group I; received saline. Group II; received isoproterenol (ISO) 15 mg/kg/day, s.c. for 20 days. Group III, IV; received 50 and 100 mg/kg/day/oral of D-Pinitol, respectively along with ISO for 20 days. Group V; received D-Pinitol 100 mg/kg/day/oral for 20 days. Group VI; received propranolol 20 mg/kg/day/oral and ISO for 20 days. Group VII; received propranolol 20 mg/kg/day/oral for 20 days. On the 21st day after behavioral tests, blood was collected and mice were sacrificed for various biochemical, histopathological, and immunohistochemical analyses.

Results

Chronic administration of isoproterenol caused neurotoxicity, cognitive dysfunction, and histopathological changes in the brain as evidenced by increase in GFAP, oxidative stress (via SOD, CAT, TBARS, and GSH), neuroinflammation (NF-kB, TNF-α, IL-6, and IL-10), and decrease in AchE and BDNF. Co-administration of D-Pinitol (100 mg/kg) significantly prevented these pathological alterations. The cognitive improvement was also observed through the forced swim test, elevated plus maze test, and rotarod test.

Conclusion

Our findings on D-Pinitol thus clearly established its neuroprotective role in ISO-induced neurodegeneration in Swiss albino mice.

Chemical characterization of the polyphenolic rich fraction of Thunbergia erecta and its therapeutic potential against doxorubicin and cyclophosphamide-induced cognitive impairment in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Thunbergia erecta (Benth.) was traditionally used as anxiolytic, sedative and antidepressant.

AIM OF THE STUDY

The study aimed to characterize T. erecta leaf ethyl acetate fraction of alcohol extract (TEAF) and evaluate its neuroprotective effect on doxorubicin and cyclophosphamide-induced chemobrain.

MATERIALS AND METHODS

Chemical profiling of TEAF was done using (Liquid chromatography coupled with mass (LC-ESI-MS/MS). In vivo chemobrain model was performed by cognitive impairment induced by doxorubicin and cyclophosphamide. Behavioral assessments included moris water maze, y maze, novel object recognition task and passive avoidance tests. Histological examination and oxidative stress markers were investigated. Protein expression of HMDGB1/RAGE/pNF-κB pathway markers was done using western blotting. All results were applied to hippocampus and prefrontal cortex of rats. Molecular docking was done within the active sites of Human Receptor for Advanced Glycation Endproducts (RAGE) using Discovery studio software.

RESULTS

Twenty-one phytoconstituents, mostly polyphenolics, were characterized in TEAF of which eleven compounds were tentatively identified for the first time from T. erecta leaves where rosmarinic acid (11) represents the most prevailing compound. TEAF resulted in a marked dose-dependent amelioration of the histopathological changes evidenced by normal histological structure demonstrated in the hypocampal gesture of rats. TEAF demonstrated an enhanced memory and learning functioning in the different behavioral tests assessed especially at 200 mg/kg. It showed significant long-term spatial memory enhancement manifested by 50.32% increase in probe trial relative to chemobrain-induced group. It showed pronounced antioxidant activity evidenced by the significant elevation of prefrontal cortical and hippocampal reduced glutathione levels by 2.45 and 2.65 folds, respectively relative to the chemobrain-induced group. The pronounced reduction in hydrogen peroxide (1.24-1.93 folds) and malondialdehyde levels (1.42-2.60 folds) with significant elevation of catalase activity (12.65-31.47%) induced by TEAF supported its potent antioxidant activity. TEAF reversed the inflammatory cytokines release induced by chemotherapy via its interference with HMGB1/RAGE pathway suppressing the expression of HMBG1, RAGE, p65 (NF-kB), and IL-1β. In silico studies showed that rosmarinic acid displayed the best fitting at the active site of RAGE (ΔG = -40.39 kcal/mol).

CONCLUSIONS

Thunbergia erecta can act as a promising remedy for chemobrain that further consolidates its traditional importance.

NLRP3 Inflammasome’s Activation in Acute and Chronic Brain Diseases—An Update on Pathogenetic Mechanisms and Therapeutic Perspectives with Respect to Other Inflammasomes

Increasingly prevalent acute and chronic human brain diseases are scourges for the elderly. Besides the lack of therapies, these ailments share a neuroinflammation that is triggered/sustained by different innate immunity-related protein oligomers called inflammasomes. Relevant neuroinflammation players such as microglia/monocytes typically exhibit a strong NLRP3 inflammasome activation. Hence the idea that NLRP3 suppression might solve neurodegenerative ailments. Here we review the recent Literature about this topic. First, we update conditions and mechanisms, including RNAs, extracellular vesicles/exosomes, endogenous compounds, and ethnic/pharmacological agents/extracts regulating NLRP3 function. Second, we pinpoint NLRP3-activating mechanisms and known NLRP3 inhibition effects in acute (ischemia, stroke, hemorrhage), chronic (Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, MS, ALS), and virus-induced (Zika, SARS-CoV-2, and others) human brain diseases. The available data show that (i) disease-specific divergent mechanisms activate the (mainly animal) brains NLRP3; (ii) no evidence proves that NLRP3 inhibition modifies human brain diseases (yet ad hoc trials are ongoing); and (iii) no findings exclude that concurrently activated other-than-NLRP3 inflammasomes might functionally replace the inhibited NLRP3. Finally, we highlight that among the causes of the persistent lack of therapies are the species difference problem in disease models and a preference for symptomatic over etiologic therapeutic approaches. Therefore, we posit that human neural cell-based disease models could drive etiological, pathogenetic, and therapeutic advances, including NLRP3’s and other inflammasomes’ regulation, while minimizing failure risks in candidate drug trials.

Pathophysiological Mechanisms Involved in Overactive Bladder/Detrusor Overactivity

Purpose of Review

To examine the latest published findings on the pathophysiological mechanisms involved in the development of overactive bladder (OAB) and detrusor overactivity (DO), and to identify common pathways linked to the risk factors associated with these conditions.

Recent Findings

Evidence is accumulating, both clinical and experimental, that many of the factors linked to the development of OAB/DO, including ageing, bladder outlet obstruction, psychological stress, and obesity are associated with reduced bladder blood flow. This induces local tissue inflammation with cytokine release and enhanced oxidative stress, ultimately resulting in altered detrusor sensitivity, detrusor hypertrophy and fibrosis, together with afferent hypersensitivity. These mechanisms would explain the symptoms of urgency and frequency observed in OAB patients. Although not a characteristic of OAB, undetected low level bacterial infections of the bladder have been proposed to explain the OAB symptoms in patients resistant to standard treatments. In this condition, inflammatory responses without reductions in perfusion activate the inflammatory pathways.

Summary

Evidence is mounting that poor bladder perfusion and local inflammatory responses are central mechanisms involved in the development of OAB/DO. As our understanding of these pathophysiological mechanisms advances, new avenues for drug development will be identified and ultimately treatment may become more individualized depending on the particular pathway involved and the drugs available.

Why Are Some People with Lower Urinary Tract Symptoms (LUTS) Depressed? New Evidence That Peripheral Inflammation in the Bladder Causes Central Inflammation and Mood Disorders

Anecdotal evidence has long suggested that patients with lower urinary tract symptoms (LUTS) develop mood disorders, such as depression and anxiety, at a higher rate than the general population and recent prospective studies have confirmed this link. Breakthroughs in our understanding of the diseases underlying LUTS have shown that many have a substantial inflammatory component and great strides have been made recently in our understanding of how this inflammation is triggered. Meanwhile, studies on mood disorders have found that many are associated with central neuroinflammation, most notably in the hippocampus. Excitingly, work on other diseases characterized by peripheral inflammation has shown that they can trigger central neuroinflammation and mood disorders. In this review, we discuss the current evidence tying LUTS to mood disorders, its possible bidirectionally, and inflammation as a common mechanism. We also review modern theories of inflammation and depression. Finally, we discuss exciting new animal studies that directly tie two bladder conditions characterized by extensive bladder inflammation (cyclophosphamide-induced hemorrhagic cystitis and bladder outlet obstruction) to neuroinflammation and depression. We conclude with a discussion of possible mechanisms by which peripheral inflammation is translated into central neuroinflammation with the resulting psychiatric concerns.

Neuroprotective potential of ferulic acid against cyclophosphamide-induced neuroinflammation and behavioral changes

In the present study, ferulic acid (FRA) has been explored for possible neuroprotective effects against cyclophosphamide (CP)-induced neurotoxicity in the Swiss Albino mice. Animals were divided into five groups and treated with FRA for fourteen days and a single dose of CP was administered on the seventh day. Animals were subjected to neurobehavioral tests such as the forced swim test and Morris Water Maze test. On day fifteenth, the brain was removed and used for biochemical analysis. The outcome of the study showed that CP administration induced significant neurotoxicity in the form of depression, anxiety, and cognitive dysfunction. Cyclophosphamide administration also reduced the activity of antioxidant enzymes, reduced the level of neurotransmitters (i.e., dopamine, 5-HT, and BDNF), anti-inflammatory cytokines (IL-10), and increased lipid peroxidation and proinflammatory cytokines (IL-1β, IL-6, and TNF-α). Additionally, CP administration increased the level of acetylcholine esterase. Treatment with FRA significantly reversed these behavioral, and biochemical markers towards normal and mitigated CP-induced neurotoxic manifestation. PRACTICAL APPLICATIONS: Ferulic acid has a variety of pharmacological activities viz. anti-inflammatory, antioxidant, antimicrobial activity, anti-cancer, and anti-diabetic effects. The results of the present study showed that FRA mitigates the neurotoxicity (i.e., alteration of neurotransmitters, inflammation, and oxidative stress) induced by CP in mice. Treatment with FRA knowingly overturned the behavioral and biochemical markers in the direction of the moderated CP-influenced neurotoxic demonstration. Thus, FRA can be useful in the prevention of anticancer drugs induced neurotoxicity. Contrariwise, supplementary in-depth studies are obligatory to bring FRA from bench to bedside that it be used as an adjuvant among chemotherapeutically treated patients.

Glibenclamide Directly Prevents Neuroinflammation by Targeting SUR1-TRPM4-Mediated NLRP3 Inflammasome Activation In Microglia

Glibenclamide (GLB) reduces brain edema and improves neurological outcome in animal experiments and preliminary clinical studies. Recent studies also suggested a strong anti-inflammatory effect of GLB, via inhibiting nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) inflammasome activation. However, it remains unknown whether the anti-inflammatory effect of GLB is independent of its role in preventing brain edema, and how GLB inhibits the NLRP3 inflammasome is not fully understood. Sprague-Dawley male rats underwent 10-min asphyxial cardiac arrest and cardiopulmonary resuscitation or sham-operation. The Trpm4 siRNA and GLB were injected to block sulfonylurea receptor 1-transient receptor potential M4 (SUR1-TRPM4) channel in rats. Western blotting, quantitative real-time polymerase chain reaction, behavioral analysis, and histological examination were used to evaluate the role of GLB in preventing NLRP3-mediated neuroinflammation through inhibiting SUR1-TRPM4, and corresponding neuroprotective effect. To further explore the underlying mechanism, BV2 cells were subjected to lipopolysaccharides, or oxygen-glucose deprivation/reperfusion. Here, in rat model of cardiac arrest with brain edema combined with neuroinflammation, GLB significantly alleviated neurocognitive deficit and neuropathological damage, via the inhibition of microglial NLRP3 inflammasome activation by blocking SUR1-TRPM4. Of note, the above effects of GLB could be achieved by knockdown of Trpm4. In vitro under circumstance of eliminating distractions from brain edema, SUR1-TRPM4 and NLRP3 inflammasome were also activated in BV2 cells subjected to lipopolysaccharides, or oxygen-glucose deprivation/reperfusion, which could be blocked by GLB or 9-phenanthrol, a TRPM4 inhibitor. Importantly, activation of SUR1-TRPM4 in BV2 cells required the P2X7 receptor-mediated Ca2+ influx, which in turn magnified the K+ efflux via the Na+ influx-driven opening of K+ channels, leading to the NLRP3 inflammasome activation. These findings suggest that GLB has a direct anti-inflammatory neuroprotective effect independent of its role in preventing brain edema, through inhibition of SUR1-TRPM4 which amplifies K+ efflux and promotes NLRP3 inflammasome activation.

The NLRP3 Inflammasome Inhibitor Dapansutrile Attenuates Cyclophosphamide-Induced Interstitial Cystitis

Interstitial cystitis (IC)/bladder pain syndrome (BPS), hereafter referred together as IC, is a clinical syndrome characterized by sterile inflammation in the bladder. While the etiology and pathophysiology of IC remain unclear, it may involve autoimmunity in light of the significant role played by the NLRP3 inflammasome. However, the effect of NLRP3 inhibitors including dapansutrile (Dap) on IC had not been explored previously. Here, we investigated the effect of Dap in the cyclophosphamide (CYP)-induced experimental mouse model of IC, which results in functional and histological alterations confined to the urinary bladder (UB) comparable to that of clinical IC. CYP-induced mice treated with Dap exhibited improved UB pathology and reductions in inflammation scores and the frequency and the number of mast cells and neutrophils, relative to mice that received CYP alone. Dap- and CYP-treated mice also exhibited infiltration of T cells in the spleen and iliac lymph nodes (ILNs) and a concurrent significant decrease (p<0.01) in CXCR3⁺CD8⁺ T cells in the UB, induction of systemic and mucosal dendritic cells (DCs), and reduced levels of systemic proinflammatory cytokines, as compared to CYP alone. We also observed decreases in the expression of several signaling pathways regulators, including interleukin-1 beta (IL-1β), NLRP3, caspase-1, nuclear factor kappa B (NF-κB), and inducible nitric oxide synthase (iNOS) in the UB of CYP- and Dap-treated mice, relative to those receiving CYP alone. Taken together, these results suggest that Dap suppresses IC through the reduction of CXCR3⁺T cells, mast cells, and neutrophils in the UB and induces DCs as a protective measure. The present study identifies the mechanisms underlying the amelioration of IC by the NLRP3 inhibitor Dap and may provide an avenue for a potential therapeutic agent for the treatment of IC.

Tilapia Skin Peptides Ameliorate Cyclophosphamide-Induced Anxiety- and Depression-Like Behavior via Improving Oxidative Stress, Neuroinflammation, Neuron Apoptosis, and Neurogenesis in Mice

Anxiety- and depression-like behavior following chemotherapy treatment occurs in cancer patients with high probability and no specific therapeutics are available for treatment and prevention of this complication. Here, tilapia skin peptides (TSP), a novel enzymatically hydrolyzed bioactive peptide mixture, obtained from tilapia (Oreochromis mossambicus) scraps, were studied on cyclophosphamide (CP)-induced anxiety- and depression-like behavior in mice. Mice were received intraperitoneal injection of CP for 2 weeks, while TSP was administered for 4 weeks. After the end of the animal experiment, behavioral, biochemical, and molecular tests were carried out. The mice decreased preference for sugar water, increased immobility time in the forced swimming and tail suspension test, and decreased travel distance in the open field test in the Model group, compared with the Control group. Abnormal changes in behavioral tests were significantly improved after the TSP treatment. Additionally, abnormalities on superoxide dismutase, malondialdehyde, glutathione peroxidase were rescued by administration of 1000 mg/kg/d TSP in mice than that of the Model group. TSP has normalized the expression of Iba-1 and the levels of TNF-α and IL-1β in the hippocampus of mice, which indicated that TSP could observably ameliorate neuroinflammatory response in the hippocampus of mice. TSP ameliorated the apoptosis of hippocampal neurons of CA1 and CA3 regions in the TSP group vs. the Model group. The number of doublecortin positive cells was drastically increased by administering 1000 mg/kg/d TSP in mice vs. the Model group. Furthermore, TSP reversed the Nrf2/HO-1 signaling pathway, BDNF/TrkB/CREB signaling pathway, and reduced the Bcl-2/Bax/caspase-3 apoptosis pathway. In conclusion, TSP could restore CP-induced anxiety- and depression-like behavior via improving oxidative stress, neuroinflammation, neuron apoptosis, and neurogenesis in mice hippocampus.

Eriodictyol and Homoeriodictyol Improve Memory Impairment in Aβ25-35-Induced Mice by Inhibiting the NLRP3 Inflammasome

(1) Alzheimer's disease (AD) is a neurodegenerative disorder, and it is now widely accepted that neuroinflammation plays a key role in its pathogenesis. Eriodictyol (Eri) and homoeriodictyol (Hom), dihydroflavonoids extracted from a variety of plants, have been confirmed to display a relationship with neuroprotection. (2) Methods: An AD mouse model was constructed by intracerebroventricular (ICV) injection of the Aβ25-35 peptide, and Eri and Hom were administered orally for 4 weeks. UPLC-MS/MS was used to determine whether Eri and Hom cross the blood-brain barrier to exert their therapeutic effects. Histological changes in the brain and levels of Aβ were evaluated, and Y-maze and new object recognition experiments were conducted to assess the effects of Eri and Hom on Aβ25-35-induced memory impairment in mice. The levels of oxidative stress and apoptosis in peripheral immune cells and progenitor cells in the hippocampal region were analyzed by flow cytometry and in vitro assays. Western blotting and enzyme-linked immunosorbent assays (ELISA) were used to measure the expression levels of NLRP3 inflammasome-related proteins and inflammatory factors in the brain. The effect of nigericin (an agonist of the NLRP3 inflammasome) on Eri and Hom intervention in LPS-induced N9 microglia was examined using a High Content Screening System. (3) Results: Eri and Hom reduced neuronal damage in mouse brain tissue, decreased Aβ levels in the brain, downregulated oxidative stress and apoptosis levels, and improved learning and memory capacity by crossing the blood-brain barrier to exert its effects. Moreover, Eri and Hom inhibited NLRP3 inflammasome activation and ameliorated immune cell disorder. Furthermore, the effect of Eri and Hom on LPS-induced N9 microglia disappeared after the addition of nigericin to agonize NLRP3 receptors. (4) Conclusions: Eri and Hom improved Aβ25-35-induced memory impairment in mice by inhibiting the NLRP3 inflammasome.

Repeated Low-Dose Acrolein Triggers Irreversible Lamina Propria Edema in Urinary Bladder, Transient Voiding Behavior and Widening of Eyes to Mechanical Stimuli

Acrolein is a metabolite of cyclophosphamide (CYP), an alkylating agent used for a wide range of benign and malignant diseases. CYP treatments are known to trigger hemorrhagic cystitis in patients and animals. Significant effort has been made to prevent CYP/acrolein-induced cystitis, while still maintaining its therapeutic benefits. As a result, supplementary therapeutic options to mediate the protective role against CYP/acrolein and lower doses of CYP are currently given to targeted patients, as compared to past treatments. There is still a need to further study the effects of the repeated low-dose CYP/acrolein on the pathophysiology of the urinary bladder. In our study, a one-time treatment of acrolein and repeated low-dose acrolein triggered the thickening of the smooth muscle and lamina propria in the urinary bladder of C57BL/6J mice, respectively. The first dose of acrolein did not trigger voiding dysfunction, but the second dose triggered high-volume low-frequency voiding. Interestingly, our new scoring criteria and concurrent behavioral assessment revealed that mice with repeated low-dose acrolein had a wider opening of eyes in response to mechanical stimuli. Our study suggests that clinical symptoms among patients undergoing prolonged low-dose CYP may differ from previously reported symptoms of CYP-induced hemorrhagic cystitis.

Integrated mRNA-miRNA transcriptome analysis of bladder biopsies from patients with bladder pain syndrome identifies signaling alterations contributing to the disease pathogenesis

Background

Interstitial cystitis, or bladder pain syndrome (IC/BPS), is a chronic bladder disorder characterized by lower abdominal pain associated with the urinary bladder and accompanied by urinary frequency and urgency in the absence of identifiable causes. IC/PBS can be separated into the classic Hunner’s ulcerative type and the more prevalent non-ulcerative disease. Our aim was to unravel the biological processes and dysregulated cell signaling pathways leading to the bladder remodeling in non-ulcerative bladder pain syndrome (BPS) by studying the gene expression changes in the patients’ biopsies.

Methods

We performed paired microRNA (miRNA) and mRNA expression profiling in the bladder biopsies of BPS patients with non-Hunner interstitial cystitis phenotype, using comprehensive Next-generation sequencing (NGS) and studied the activated pathways and altered biological processes based on the global gene expression changes. Paired mRNA-miRNA transcriptome analysis delineated the regulatory role of the dysregulated miRNAs by identifying their targets in the disease-induced pathways.

Results

EIF2 Signaling and Regulation of eIF4 and p70S6K Signaling, activated in response to cellular stress, were among the most significantly regulated processes during BPS. Leukotriene Biosynthesis nociceptive pathway, important in inflammatory diseases and neuropathic pain, was also significantly activated. The biological processes identified using Gene Ontology over-representation analysis were clustered into six main functional groups: cell cycle regulation, chemotaxis of immune cells, muscle development, muscle contraction, remodeling of extracellular matrix and peripheral nervous system organization and development. Compared to the Hunner’s ulcerative type IC, activation of the immune pathways was modest in non-ulcerative BPS, limited to neutrophil chemotaxis and IFN-γ-mediated signaling. We identified 62 miRNAs, regulated and abundant in BPS and show that they target the mRNAs implicated in eIF2 signalling pathway.

Conclusions

The bladders of non-ulcerative BPS patients recruited in this study had alterations consistent with a strong cell proliferative response and an up-regulation of smooth muscle contractility, while the contribution of inflammatory processes was modest. Pathway analysis of the integrated mRNA-miRNA NGS dataset pinpointed important regulatory miRNAs whose dysregulation might contribute to the pathogenesis. Observed molecular changes in the peripheral nervous system organization and development indicate the potential role of local bladder innervation in the pain perceived in this type of BPS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12894-021-00934-0.

Inflammasomes as therapeutic targets in human diseases

Inflammasomes are protein complexes of the innate immune system that initiate inflammation in response to either exogenous pathogens or endogenous danger signals. Inflammasome multiprotein complexes are composed of three parts: a sensor protein, an adaptor, and pro-caspase-1. Activation of the inflammasome leads to the activation of caspase-1, which cleaves pro-inflammatory cytokines such as IL-1β and IL-18, leading to pyroptosis. Effectors of the inflammasome not only provide protection against infectious pathogens, but also mediate control over sterile insults. Aberrant inflammasome signaling has been implicated in the development of cardiovascular and metabolic diseases, cancer, and neurodegenerative disorders. Here, we review the role of the inflammasome as a double-edged sword in various diseases, and the outcomes can be either good or bad depending on the disease, as well as the genetic background. We highlight inflammasome memory and the two-shot activation process. We also propose the M- and N-type inflammation model, and discuss how the inflammasome pathway may be targeted for the development of novel therapy.

Reduced NLRP3 inflammasome expression in the brain is associated with stress resilience

Increased expression of the Nod-like receptor pyrin containing 3 (NLRP3) inflammasome and proinflammatory cytokines is associated with depressive behaviors. This study aimed to explore potential differences in neuroinflammation associated with stress resilience, as well as associated changes in autophagy, in a mouse model of chronic unpredictable mild stress (CUMS). Animals were classified as CUMS resilient or CUMS susceptible based on performance on behavioral tests following the CUMS protocol. Then the expression levels of NLRP3 inflammasome-related proteins, interleukin-1 beta (IL-1β), and Beclin 1 in stress-related brain regions (e.g., prefrontal cortex and hippocampus) were determined. Results showed that stress exposure triggered significant NLRP3 inflammasome increase in CUMS susceptible mice but not in CUMS resilient mice. These changes were accompanied by altered IL-1β and Beclin 1 expression levels. These findings indicate that stress resilience is associated with reduced pro-inflammatory signaling and autophagy activation, and suggest that therapeutically targeting these pathways might promote stress resilience.

NLRP3 Inflammasome: A Promising Therapeutic Target for Drug-Induced Toxicity

Drug-induced toxicity, which impairs human organ function, is a serious problem during drug development that hinders the clinical use of many marketed drugs, and the underlying mechanisms are complicated. As a sensor of infections and external stimuli, nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain containing 3 (NLRP3) inflammasome plays a key role in the pathological process of various diseases. In this review, we specifically focused on the role of NLRP3 inflammasome in drug-induced diverse organ toxicities, especially the hepatotoxicity, nephrotoxicity, and cardiotoxicity. NLRP3 inflammasome is involved in the initiation and deterioration of drug-induced toxicity through multiple signaling pathways. Therapeutic strategies via inhibiting NLRP3 inflammasome for drug-induced toxicity have made significant progress, especially in the protective effects of the phytochemicals. Growing evidence collected in this review indicates that NLRP3 is a promising therapeutic target for drug-induced toxicity.

Nano-engineered nerolidol loaded lipid carrier delivery system attenuates cyclophosphamide neurotoxicity - Probable role of NLRP3 inflammasome and caspase-1

Neuroinflammation is one of the most common etiology in various neurological disorders and responsible for multi-array neurotoxic manifestations such as neurodegeneration, neurotransmitters alteration and cognitive dysfunction. NR (Nerolidol) is a natural bioactive molecule which possesses significant antioxidant and anti-inflammatory potential, but suffers from glitches of low solubility, low bioavailability and fast hepatic metabolism. In the current study, we fabricated nano-engineered lipid carrier of nerolidol (NR-NLC) for its effective delivery into the brain and explored its effect on neuroinflammation, neurotransmitters level and on dysfunctional behavioral attributes induced by CYC (cyclophosphamide). The binding affinity of nerolidol with NLRP3 and TLR-4 was performed which showed stong interaction between them. NR-NLC was prepared by the ultrasonication methods and particle size was determined by Zeta-sizer. Swiss Albino mice were divided into 5 groups (n = 6), assessed for behavioral dysfunction, and sacrificed on the fifteenth day following cyclophosphamide treatment. Brains were then removed and used for biochemical, histopathological, immunohistochemical and fluorescence microscopic analysis. Biochemical analysis showed increased levels of MDA, TNF-α, IL-6, IL-1β, acetylcholine esterase, BDNF, 5-HT and dopamine, and reduced levels of SOD, CAT, GSH, IL-10, along with significant behavioral dysfunction in cyclophosphamide-treated animals. Significant neuronal damage was also observed in the histological study. Immunohistochemical analysis demonstrated increased expression of NLRP3 and caspase-1. Fluorescence microscopic analysis showed significant availability of NR-NLC in the hippocampus and cortex region. In contrast, treatment with NR-NLC effectively mitigated the aforementioned neurotoxic manifestation as compared to NR suspension. Our results showed potent neuroprotective effect of NR-NLC via modulation of oxidative stress, NLRP3 inflammasome, caspase-1 and neurotransmitter status.

A possible mechanism underlying mood disorders associated with LUTS: Chronic bladder outlet obstruction causes NLRP3-dependent inflammation in the hippocampus and depressive behavior in rats

AIMS

Reports link urinary dysfunction and mood disorders, such as depression, but a causative mechanism has never been postulated. Contemporary discoveries demonstrate a local inflammatory response in peripheral organs can trigger inflammation in the brain, particularly the hippocampus, mediated through the NLRP3 inflammasome. Critically, central inflammation causes depressive behavior. Since bladder outlet obstruction (BOO) evokes a local inflammatory response in the bladder, we hypothesize it will induce NLRP3-dependent inflammation in the hippocampus and depressive behavior.

METHODS

There were four groups of rats: control, sham, BOO, or BOO + glyburide (an NLRP3 inhibitor). BOO was created by urethral ligation over a 1 mm catheter. Sham was tied loosely. Glyburide was provided by slow-release pellet (subcutaneous 50 mg, 21 day, replaced as needed). Rats were analyzed 12 weeks post-op for: hippocampal inflammation, microglial density, neurogenesis, and depression symptoms (open field and sucrose preference).

RESULTS

BOO elicited hippocampal inflammation, accompanied by an increase in activated microglia (22%) and a decrease in neurogenesis (35%), which was blocked by glyburide. In addition, BOO rats displayed anxiety (57% decrease in exploratory behavior in the open field assay) and anhedonia (21% decrease in sucrose preference), two symptoms of depression. Like inflammation, these symptoms were diminished by glyburide to levels not statistically significantly different from controls.

CONCLUSIONS

BOO, a bladder-localized event, stimulates NLRP3-dependent inflammation in the rat hippocampus after 12 weeks and this inflammation causes depressive behavior. This is the first mechanistic explanation of the link between BOO and depression and provides evidence for a distinct bladder-brain axis.