Bezafibrate confers neuroprotection in the 5xFAD mouse model of Alzheimer's disease

PIEZO1 as a new target for hyperglycemic stress-induced neuropathic injury: The potential therapeutic role of bezafibrate

Hyperglycemic stress can directly lead to neuronal damage. The mechanosensitive ion channel PIEZO1 can be activated in response to hyperglycemia, but its role in hyperglycemic neurotoxicity is unclear. The role of PIEZO1 in hyperglycemic neurotoxicity was explored by constructing a hyperglycemic mouse model and a high-glucose HT22 cell model. The results showed that PIEZO1 was significantly upregulated in response to high glucose stress. In vitro experiments have shown that high glucose stress induces changes in neuronal cell morphology and membrane tension, a key mechanism for PIEZO1 activation. In addition, high glucose stress upregulates serum/glucocorticoid-regulated kinase-1 (SGK1) and activates PIEZO1 through the Ca2+ pool and store-operated calcium entry (SOCE). PIEZO1-mediated Ca2+ influx further enhances SGK1 and SOCE, inducing intracellular Ca2+ peaks in neurons. PIEZO1 mediated intracellular Ca2+ elevation leads to calcium/calmodulin-dependent protein kinase 2α (CaMK2α) overactivation, which promotes oxidative stress and apoptosis signalling through p-CaMK2α/ERK/CREB and ox-CaMK2α/MAPK p38/NFκB p65 pathways, subsequently inducing synaptic damage and cognitive impairment in mice. The intron miR-107 of pantothenic kinase 1 (PANK1) is highly expressed in the brain and has been found to target PIEZO1 and SGK1. The PANK1 receptor is activated by peroxisome proliferator-activated receptor α (PPARα), an activator known to upregulate miR-107 levels in the brain. The clinically used lipid-lowering drug bezafibrate, a known PPARα activator, may upregulate miR-107 through the PPARɑ/PANK1 pathway, thereby inhibiting PIEZO1 and improving hyperglycemia-induced neuronal cell damage. This study provides a new idea for the pathogenesis and drug treatment of hyperglycemic neurotoxicity and diabetes-related cognitive dysfunction.

Bezafibrate protects blood-brain barrier (BBB) integrity against traumatic brain injury mediated by AMPK

Bezafibrate (BEZ) has displayed a wide range of neuroprotective effects in different types of neurological diseases. However, its pharmacological function in traumatic brain injury (TBI) is still unknown. In the current study, a TBI model was constructed in mice to examine the potential beneficial roles of BEZ. After TBI, mice were daily dieted with BEZ or vehicle solution. The motor function, learning and memory, brain edema, vascular inflammatory factors, the integrity of the blood-brain barrier (BBB), and the expression of the tight junction zona occludens 1 (ZO-1) were assessed. The findings demonstrate that after TBI, BEZ treatment significantly promoted the recovery of motor function and cognitive function deficits. Moreover, BEZ attenuated brain edema by reducing the levels of brain water content. We also found that administration of BEZ alleviated cerebral vascular pro-inflammation by suppressing the expression of ICAM-1, VCAM-1, and E-selectin. Notably, BEZ improved the impaired BBB integrity in TBI mice by restoring the expression of the tight junction (TJ) protein ZO-1. Further in vitro experiments show that treatment with BEZ prevented the aggravation of endothelial permeability and restored the reduction of trans-epithelial electrical resistance (TEER) as well as the expression of ZO-1 in TBI-exposed brain bEnd.3 cells. Mechanistically, we prove that the protective effects of BEZ are mediated by AMPK. Based on these findings, we conclude that BEZ improves TBI-induced BBB injury and it might be considered for the treatment or management of TBI.

PPAR agonists for the treatment of neuroinflammatory diseases

Peroxisome proliferator-activated receptors [PPARs; PPARα, PPARβ/δ (also known as PPARδ), and PPARγ] widely recognized for their important role in glucose/lipid homeostasis, have recently received significant attention due to their additional anti-inflammatory and neuroprotective effects. Several newly developed PPAR agonists have shown high selectivity for specific PPAR isoforms in vitro and in vivo, offering the potential to achieve desired therapeutic outcomes while reducing the risk of adverse effects. In this review, we discuss the latest preclinical and clinical studies of the activation of PPARs by synthetic, natural, and isoform-specific (full, partial, and dual) agonists for the treatment of neuroinflammatory diseases, including HIV-associated neurocognitive disorders (HAND), Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), and cerebral ischemia.