Preparation of VX765 sodium alginate nanogels and evaluation of their therapeutic effect via local injection on myocardial infarction in rats

Myocardial Infarction (MI) is major cause of heart failure, highlighting the critical need for effective therapeutic strategies to improve cardiac repair. This study investigated the cardioprotective effects of VX765-coated polyethyleneimine (PEI)/sodium alginate (AG) composite nanogels (AG/PEI-VX765 NGs) in a rat model of MI. Additionally, AG-VX765 NGs and PEI-VX765 nanospheres (NPs) were synthesized and tested to compare their efficacy. MI was caused in rats by ligating the left anterior descending branch of the coronary artery, and the rats were grouped and set as Sham, MI, MI + VX765, MI + AG-VX765NGs, MI + PEI-VX765NPs, and MI + AG/PEI-VX765NGs. Results demonstrate that AG/PEI-VX765NGs were non-toxic and exhibited a sustained release of VX765. In vivo, experiments demonstrated that all treatment groups significantly enhanced cardiac function, reduced infarct size, fibrosis, and apoptosis in rats with MI, with the MI + AG/PEI-VX765NGs group exhibiting the most favorable outcomes. Our findings indicate that AG/PEI-VX765NGs represent a promising therapeutic approach for MI treatment.

Extracellular vesicles encapsulated with caspase-1 inhibitor ameliorate experimental autoimmune myasthenia gravis through targeting macrophages

Cysteinyl aspartate-specific proteinase-1 (caspase-1) is a multifunctional inflammatory mediator in many inflammation-related diseases. Previous studies show that caspase-1 inhibitors produce effective therapeutic outcomes in a rat model of myasthenia gravis. However, tissue toxicity and unwanted off-target effects are the major disadvantages limiting their clinical application as therapeutic agents. This study shows that dendritic cell-derived extracellular vesicles (EVs) loaded with a caspase-1 inhibitor (EVs-VX-765) are phagocytized mainly by macrophages, and caspase-1 is precisely expressed in macrophages. Furthermore, EVs-VX-765 demonstrates excellent therapeutic effects through a macrophage-dependent mechanism, and it notably inhibits the level of interleukin-1β and subsequently inhibits Th17 response and germinal center (GC) reactions. In addition, EVs-VX-765 demonstrates better therapeutic effects than routine doses of VX-765, although drug loading is much lower than routine doses, consequently reducing tissue toxicity. In conclusion, this study's findings suggest that EV-mediated delivery of caspase-1 inhibitors is effective for treating myasthenia gravis and is promising for clinical applications.

Novel Caspase-1 inhibitor CZL80 improves neurological function in mice after progressive ischemic stroke within a long therapeutic time-window

Progressive ischemic stroke (PIS) is featured by progressive neurological dysfunction after ischemia. Ischemia-evoked neuroinflammation is implicated in the progressive brain injury after cerebral ischemia, while Caspase-1, an active component of inflammasome, exaggerates ischemic brain injury. Current Caspase-1 inhibitors are inadequate in safety and druggability. Here, we investigated the efficacy of CZL80, a novel Caspase-1 inhibitor, in mice with PIS. Mice and Caspase-1-/- mice were subjected to photothrombotic (PT)-induced cerebral ischemia. CZL80 (10, 30 mg·kg-1·d-1, i.p.) was administered for one week after PT onset. The transient and the progressive neurological dysfunction (as foot faults in the grid-walking task and forelimb symmetry in the cylinder task) was assessed on Day1 and Day4-7, respectively, after PT onset. Treatment with CZL80 (30 mg/kg) during Day1-7 significantly reduced the progressive, but not the transient neurological dysfunction. Furthermore, we showed that CZL80 administered on Day4-7, when the progressive neurological dysfunction occurred, produced significant beneficial effects against PIS, suggesting an extended therapeutic time-window. CZL80 administration could improve the neurological function even as late as Day43 after PT. In Caspase-1-/- mice with PIS, the beneficial effects of CZL80 were abolished. We found that Caspase-1 was upregulated during Day4-7 after PT and predominantly located in activated microglia, which was coincided with the progressive neurological deficits, and attenuated by CZL80. We showed that CZL80 administration did not reduce the infarct volume, but significantly suppressed microglia activation in the peri-infarct cortex, suggesting the involvement of microglial inflammasome in the pathology of PIS. Taken together, this study demonstrates that Caspase-1 is required for the progressive neurological dysfunction in PIS. CZL80 is a promising drug to promote the neurological recovery in PIS by inhibiting Caspase-1 within a long therapeutic time-window.

The anti-inflammatory and analgesic effects of intraperitoneal melatonin after spinal nerve ligation are mediated by inhibition of the NF-κB/NLRP3 inflammasome signaling pathway

OBJECTIVE

To explore the potential analgesic effect of melatonin and its underlying molecular mechanisms in a neuropathic pain model induced by spinal nerve ligation (SNL).

METHODS

The experimental animals were divided into different groups including sham, vehicle, melatonin (MT) treatment, caspase-1 inhibitor (VX-765) treatment and MT2 antagonist (4P-PDOT) treatment. On the first three successive postoperative days, rats were intraperitoneally administered with MT, VX-765 or combination of MT and 4P-PDOT. Hyperalgesic behavior after SNL was evaluated using the paw withdrawal threshold (PWT). We then assessed expression of tumor necrosis factor-α (TNF-α), IL-18, interleukin-1β (IL-1β), NLRP3 inflammasome components, and nuclear factor-κB (NF-κB) activation using enzyme-linked immunosorbent assay kits (ELISA), real-time PCR, immunohistochemistry, and western blot, respectively, in spinal cord horn tissues extracted on postoperative day 7.

RESULTS

The results showed that melatonin treatment alleviated SNL-induced allodynia. We observed an SNL-induced upregulation of TNF-α, IL-18, IL-1β, NLRP3, ASC, cleaved caspase-1, and NF-κB in the lumbar spinal cord horn of rats, which was significantly attenuated by intraperitoneal injection of melatonin or VX-765. Additionally, co-treatment of melatonin and 4P-PDOT abrogated the analgesic and anti-inflammatory effect of melatonin.

CONCLUSION

Melatonin had potent analgesic and anti-inflammatory effects in SNL-induced neuropathic pain via NF-κB/NLRP3 inflammasome signaling pathway. Our results therefore suggested that this pathway could represent a novel therapeutic target for the management of neuropathic pain.

A Novel Mechanism of Specialized Proresolving Lipid Mediators Mitigating Radicular Pain: The Negative Interaction with NLRP3 Inflammasome

Inhibition of immune and inflammatory reaction induced by the expose of nucleus pulposus (NP) could effectively ameliorate neuropathic pain in the lumbar disc herniation. Maresin1 (MaR1), as a macrophage-derived mediator of inflammation resolution, displayed potent anti-inflammatory action. In the present study, we attempted to elucidate the impact of MaR1 on radicular pain and the interaction with NLRP3 inflammasome. We established a rat model of non-compressive lumbar disc herniation and different administration (MaR1 or Caspase-1 inhibitor) was given to them. The paw withdrawal latency (PWL) and paw withdrawal thresholds (PWTs) were observed to assess pain behaviors. The spinal cord horns were collected and the levels of IL-1β and IL-18 were measured by ELISA. The mRNA and protein expression levels of NLRP3 inflammasome components were tested by RT-PCR, western blot and immunohistochemistry. The endogenous MaR1 levels of the spinal cord were analyzed using LC-MS/MS. The application of NP in the models lead to mechanical and thermal hypersensitivity, increased IL-1β and IL-18 levels and expressions of NLRP3 inflammasome components, which were reversed markedly by administration of MaR1. Caspase-1 inhibition also improved mechanical hypersensitivity, decreased the expressions of inflammatory cytokines and restrained the activation of inflammasome. Meanwhile, Caspase-1 inhibitor promoted the endogenous MaR1 synthesis, which was hindered in the pain models. Altogether, our study indicated that the negative interaction between MaR1 and NLRP3 inflammasome mediated the inflammatory response in spinal dorsal horn, which involved in the pathogenesis of radicular pain.

Identification and validation of uterine stimulant methylergometrine as a potential inhibitor of caspase-1 activation

Inflammasomes are intracellular multiprotein complexes of the innate immune system. Upon an inflammatory insult, such as infection or intracellular damage, a nucleotide-binding oligomerization domain-like receptor (NLR) sensor protein and the adaptor protein ASC (apoptosis-associated speck-like protein containing a caspase activation and recruitment domain) are assembled to activate protease procaspase-1. This protease processes pro-IL-1β and pro-IL-18 cytokines, which are released to induce the inflammatory response. De-regulation of inflammasome contributes to the progression of several diseases, such as Alzheimer’s disease, diabetes, cancer, inflammatory and autoimmune disorders. We herein describe the identification of methylergometrine (MEM), a drug currently used as a smooth muscle constrictor during postpartum hemorrhage, as an inhibitor of the inflammasome complex in ASC-mediated procaspase-1 activation screening. MEM inhibits the activation of the nucleotide-binding oligomerization domain-like receptor protein 1 (NLRP1) and nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasomes in cellular models upon different pro-inflammatory stimuli. Our results suggest that MEM has the potential to reposition in the treatment of inflammatory diseases with the advantages of established safety and clinical data.

Targeting the inflammasome and adenosine type-3 receptors improves outcome of antibiotic therapy in murine anthrax

AIM: To establish whether activation of adenosine type-3 receptors (A3Rs) and inhibition of interleukin-1β-induced inflammation is beneficial in combination with antibiotic therapy to increase survival of mice challenged with anthrax spores.

METHODS: DBA/2 mice were challenged with Bacillus anthracis spores of the toxigenic Sterne strain 43F2. Survival of animals was monitored for 15 d. Ciprofloxacin treatment (50 mg/kg, once daily, intraperitoneally) was initiated at day +1 simultaneously with the administration of inhibitors, and continued for 10 d. Two doses (2.5 mg/kg and 12.5 mg/kg) of acetyl-tyrosyl-valyl-alanyl-aspartyl-chloromethylketone (YVAD) and three doses (0.05, 0.15 and 0.3 mg/kg) of 1-[2-Chloro-6-[[(3-iodophenyl) methyl]amino]-9H-purin-9-yl]-1-deoxy-N-methyl-β-D- ribofuranuronamide (Cl-IB-MECA) were tested. Animals received YVAD on days 1-4, and Cl-IB-MECA on days 1-10 once daily, subcutaneously. Human lung epithelial cells in culture were challenged with spores or edema toxin and the effects of IB-MECA on phosphorylation of AKT and generation of cAMP were tested.

RESULTS: We showed that the outcome of antibiotic treatment in a murine anthrax model could be substantially improved by co-administration of the caspase-1/4 inhibitor YVAD and the A3R agonist Cl-IB-MECA. Combination treatment with these substances and ciprofloxacin resulted in up to 90% synergistic protection. All untreated mice died, and antibiotic alone protected only 30% of animals. We conclude that both substances target the aberrant host signaling that underpins anthrax mortality.

CONCLUSION: Our findings suggest new possibilities for combination therapy of anthrax with antibiotics, A3R agonists and caspase-1 inhibitors.