PPAR-α acutely inhibits functional activity of ASICs in rat dorsal root ganglion neurons

Fenofibrate ameliorates nitroglycerin-induced migraine in rats: Role of CGRP/p-CREB/P2X3 and NGF/PKC/ASIC3 signaling pathways

Migraine, a debilitating neurological condition, significantly affects patients' quality of life. Fenofibrate, a peroxisome proliferator-activated receptor alpha (PPAR-α) agonist approved for managing dyslipidemia, has shown promise in treating neurological disorders. Therefore, this study aims to investigate the protective effects of fenofibrate against nitroglycerin (NTG)-induced chronic migraine in rats. Migraine was induced in rats by administering five intermittent doses of NTG (10 mg/kg, i. p.) on days 1, 3, 5, 7, and 9. Rats were treated with either topiramate (80 mg/kg/day, p. o.), a standard drug, or fenofibrate (100 mg/kg/day, p. o.) from day 1-10. Fenofibrate significantly improved mechanical and thermal hypersensitivity, photophobia, and head grooming compared to topiramate. These effects were associated with reduced serum levels of nitric oxide (NO), calcitonin gene-related peptide (CGRP), and pituitary adenylate cyclase-activating polypeptide (PACAP). Furthermore, fenofibrate down-regulated c-Fos expression in the medulla and medullary pro-inflammatory cytokine contents. Additionally, fenofibrate attenuated NTG-induced histopathological changes in the trigeminal ganglia and trigeminal nucleus caudalis. These effects were associated with the inhibition of CGRP/p-CREB/purinergic 2X receptor 3 (P2X3) and nerve growth factor (NGF)/protein kinase C (PKC)/acid-sensing ion channel 3 (ASIC3) signaling pathways. This study demonstrates that fenofibrate attenuated NTG-induced migraine-like signs in rats. These effects were partially mediated through the inhibition of CGRP/p-CREB/P2X3 and NGF/PKC/ASIC3 signaling pathways. The present study supports the idea that fenofibrate could be an effective candidate for treating migraine headache without significant adverse effects. Future studies should explore its clinical applicability.

Can pyroptosis be a new target in rheumatoid arthritis treatment?

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease of undefined etiology, with persistent synovial inflammation and destruction of articular cartilage and bone. Current clinical drugs for RA mainly include non-steroidal anti-inflammatory drugs (NSAIDs), glucocorticoids, disease modifying anti-rheumatic drugs (DMARDs) and so on, which can relieve patients' joint symptoms. If we want to have a complete cure for RA, there are still some limitations of these drugs. Therefore, we need to explore new mechanisms of RA to prevent and treat RA radically. Pyroptosis is a newly discovered programmed cell death (PCD) in recent years, which is characterized by the appearance of holes in cell membranes, cell swelling and rupture, and the release of intracellular pro-inflammatory factors into the extracellular space, resulting in a strong inflammatory response. The nature of pyroptosis is pro-inflammatory, and whether it is participating in the development of RA has attracted a wide interest among scholars. This review describes the discovery and mechanism of pyroptosis, the main therapeutic strategies for RA, and the role of pyroptosis in the mechanism of RA development. From the perspective of pyroptosis, the study of new mechanisms of RA may provide a potential target for the treatment of RA and the development of new drugs in the clinics.

Spatiotemporal control of necroptotic cell death and plasma membrane recruitment using engineered MLKL domains

Necroptosis is a form of programmed necrotic cell death in which a signaling cascade induces oligomerization of mixed lineage kinase domain-like (MLKL) protein, leading to plasma membrane rupture. Necroptotic cell death is recognized as important for protection against viral infection and has roles in a variety of diseases, including cancer and diabetes. Despite its relevance to health and disease states, many questions remain about the precise mechanism of necroptotic cell death, cellular factors that can protect cells from necroptosis, and the role of necroptosis in disease models. In this study, we engineered a light-activated version of MLKL that rapidly oligomerizes and is recruited to the plasma membrane in cells exposed to light, inducing rapid cell death. We demonstrate this tool can be controlled spatially and temporally, used in a chemical genetic screen to identify chemicals and pathways that protect cells from MLKL-induced cell death, and used to study signaling responses of non-dying bystander cells. In additional studies, we re-engineered MLKL to block its cell-killing capacity but retain light-mediated membrane recruitment, developing a new single-component optogenetic tool that allows modulation of protein function at the plasma membrane.

Effects of Dual Peroxisome Proliferator-Activated Receptors α and γ Activation in Two Rat Models of Neuropathic Pain

Neuropathic pain is a growing healthcare problem causing a global burden. Currently used analgesics such as opioids are associated with adverse effects; urging the need for safer alternatives. Here we aimed to investigate the potential analgesic effects of tesaglitazar; dual peroxisome proliferator-activated receptors α and γ (PPARα and γ) agonist in rat models of neuropathic pain. This study also aimed to investigate the modulation of the transient receptor potential vanilloid 1 (TRPV1) receptor activity by tesaglitazar which could provide a potential mechanism that underlie tesaglitazar antinociceptive effects. Von Frey filaments were used to determine the paw withdrawal threshold (PWT) in adult male Sprague Dawley rats (180-250g) following i.p. injection of streptozotocin (STZ) or cisplatin, which were used as models of neuropathic pain. Antinociceptive effects of tesaglitazar were determined 6 hours after drug administration. Cobalt influx assays in cultured dorsal root ganglia (DRG) neurons were used to study the effects of tesaglitazar preincubation on capsaicin-evoked cobalt influx. Both cisplatin and STZ produced a significant decrease in PWT. The higher dose of tesaglitazar (20μg/kg) significantly restored PWT in both neuropathic pain models (P<0.05). 10μM capsaicin produced a robust cobalt response in DRG neurons. Preincubation of DRG neurones with tesaglitazar 6 hours prior to stimulation with capsaicin significantly reduce capsaicin-evoked cobalt responses in a PPARα and PPARγ dependent fashion (P<0.05). In conclusion, tesaglitazar produced significant analgesic effects in STZ and cisplatin-induced neuropathy, possibly by modulating TRPV1 receptor activity. This may be of potential benefit in clinical practice dealing with peripheral neuropathy.