LPS Mediates Bovine Endometrial Epithelial Cell Pyroptosis Directly Through Both NLRP3 Classical and Non-Classical Inflammasome Pathways

Abstract

As a highly inflammatory form of programmed cell death, pyroptosis is triggered by pro-inflammatory signals and associated with inflammation. It is characterized by cell swelling and large bubbles emerging from the plasma membrane, which release cytokines during inflammation. Compared with other types of cell death, pyroptosis has a distinct morphology and mechanism and involves special inflammasome cascade pathways. However, the inflammasome mechanism through which endometrial epithelial cell pyroptosis occurs in LPS-mediated inflammation remains unclear. We confirmed that there was an increased mRNA and protein expression of the IL-6, TNF-α, IL-1β, IL-18 cytokines, the inflammasome molecules NLRP3, CASPASE-1, CASPASE-4, and GSDMD in LPS-induced primary bovine endometrial epithelial cells (BEECs) in an in vitro established inflammatory model using ELISA, real-time PCR (RT-PCR), vector construction and transfection, and Western blotting. Scanning electron microscopy and lactate dehydrogenase (LDH) activity assays revealed induced cell membrane rupture, which is the main characteristic of pyroptosis. In conclusion, the cytolytic substrate GSDMD’s cleavage by caspase-1 or caspase-4 through the NLRP3 classical and non-classical inflammasome pathways, GSDMD N-terminus bind to the plasma membrane to form pores and release IL -18, IL-1β cause cell death during LPS induced BEECs inflammation.

Transforming growth factor-β1 protects against LPC-induced cognitive deficit by attenuating pyroptosis of microglia via NF-κB/ERK1/2 pathways

“…The morphological changes of pyroptosis are characterized by cellular swelling, emergence of bubbles from the plasma membrane and cell membrane rupture [45,46]. Consistent with the published studies [45][46][47], using scanning electron microscopy, we observed emergence of typical bubbles from plasma membrane and obvious cell membrane rupture in microglia treated with LPS for 24 h. Yet, TGF-β1 administration greatly relieved above pyroptosis-characteristic morphological changes caused by LPS (Fig. 6B).…”

The Role of NLRP3 Inflammasome in Alzheimer’s Disease and Potential Therapeutic Targets

“…A certain number of exogenous or endogenous stimuli that induce the activation of NLRP3 inflammasome have been confirmed so far. The exogenous stimulating factors include lipopolysaccharide (LPS) ( Ma et al, 2021 ), viral RNA ( Allen et al, 2009 ), palmitate ( Byeon et al, 2017 ), silica dioxide ( Ko et al, 2020 ) and so on, while the damage-associated endogenous activators consist of ROS ( Li et al, 2020a ), cathepsin B ( Bai et al, 2018 ), ATP ( Amores-Iniesta et al, 2017 ), Aβ oligomers ( Van Zeller et al, 2021 ), α -synuclein ( α -syn) ( Wang et al, 2020 ), etc. Although the process of NLRP3 inflammasome activation induced by the above factors has been extensively studied, the exact molecular mechanisms still need to be further explored.…”

mRNA-carrying lipid nanoparticles that induce lysosomal rupture activate NLRP3 inflammasome and reduce mRNA transfection efficiency

“…One of the most widely studied inflammasomes, the NLRP3 inflammasome, is a multimeric protein complex that forms as a response to various stress and damage signals in innate immune cells. 15–19 NLRP3 inflammasomes are activated in a dual-signal process. In signal 1, lipopolysaccharide (LPS), which is found in the cell walls of Gram-negative bacteria, is sensed by cell signaling complexes such as toll-like receptor 4 on the surface of macrophages, resulting in the downstream activation of NF-κB transcription factor, inducing the production of inactive proteins involved in the NLRP3 inflammasome complex, including NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) (Fig.…”

“…1F–H). 15–19 It has been discovered that nanoparticles can activate signal 2 and induce NLRP3 inflammasome activation, wherein Nanoparticle-Associated Molecular Patterns (NAMPs) such as size, material, charge, and hydrophobicity determine the strength of activation. 15,20–24 Previous literature has elucidated that individual mRNA lipid nanoparticle components are able to activate inflammasomes.…”