Increased NLRP3 Inflammasome Activation and Pyroptosis in Patients With Multiple Sclerosis With Fingolimod Treatment Failure

Abstract

Background and ObjectivesInflammasomes are involved in the pathogenesis of different neuroimmune and neurodegenerative diseases, including multiple sclerosis (MS). In a previous study by our group, the nucleotide-binding oligomerization domain, leucine-rich repeat receptor and pyrin-domain–containing 3 (NLRP3) inflammasome was reported to be associated with the response to interferon-beta in MS. Based on recent data showing the potential for the oral therapy fingolimod to inhibit NLRP3 inflammasome activation, here we investigated whether fingolimod could also be implicated in the response to this therapy in patients with MS.MethodsNLRP3gene expression levels were measured by real-time PCR in peripheral blood mononuclear cells at baseline and after 3, 6, and 12 months in a cohort of patients with MS treated with fingolimod (N = 23), dimethyl fumarate (N = 21), and teriflunomide (N = 21) and classified into responders and nonresponders to the treatment according to clinical and radiologic criteria. In a subgroup of fingolimod responders and nonresponders, the percentage of monocytes with an oligomer of ASC was determined by flow cytometry, and the levels of interleukin (IL)-1β, IL-18, IL-6, tumor necrosis factor (TNF)α, and galectin-3 were quantified by ELISA.ResultsNLPR3expression levels were significantly increased in fingolimod nonresponders after 3 (p= 0.03) and 6 months (p= 0.008) of treatment compared with the baseline but remained similar in responders at all time points. These changes were not observed in nonresponders to the other oral therapies tested. The formation of an oligomer of ASC in monocytes after lipopolysaccharide and adenosine 5′-triphosphate stimulation was significantly decreased in responders (p= 0.006) but increased in nonresponders (p= 0.0003) after 6 months of fingolimod treatment compared with the baseline. Proinflammatory cytokine release from stimulated peripheral blood mononuclear cells was comparable between responders and nonresponders, but galectin-3 levels on cell supernatants, as a marker of cell damage, were significantly increased in fingolimod nonresponders (p= 0.02).DiscussionThe differential effect of fingolimod on the formation of an inflammasome-triggered ASC oligomer in monocytes between responders and nonresponders could be used as a response biomarker after 6 months of fingolimod treatment and suggests that fingolimod may exert their beneficial effects by reducing inflammasome signaling in a subset of patients with MS.

Flow Cytometry: A Versatile and Powerful Tool for Drug Discovery and Development

“…Pyroptosis is a type of inflammatory programmed cell death which is induced by caspase cleavage and gasdermins and results in the secretion of inflammatory mediators interleukin 1β and interleukin 18 (63)(64)(65). This cell death pathway has been reported to be involved in carcinogenesis as well as autoimmune, neurodegenerative or allergic diseases (66)(67)(68)(69). Therefore, pyroptosis is considered as an attractive target for treating a wide array of diseases (70,71).…”

Cognitive Impairment in Multiple Sclerosis

“…Pyroptosis also may have an important function in MS and the treatment of patients. Increased inflammasome expression has been associated with potential treatment failures in MS patients [286], as well as the increased inflammatory activity of cytokine release and immune cell activity in experimental models [134]. Pyroptosis is a programmed cell death pathway that can oversee inflammatory cell activation in the nervous system [34,66,169,212,213].…”

“…It should be noted that inflammasomes are cytosolic oligomers of multiple proteins, and the inflammasome family with NLRs (nucleotide-binding oligomerization domain and leucine-rich repeat-containing receptors) contains NLRP1, NLRP3, NLRP6, and NLRC4. Inflammasome activation can occur through pattern recognition receptors responding to the damage-associated molecular pattern (DAMP) of host cells or pathogen-associated molecular pattern (PAMP) in the microbial family [34,66,134,185,212,213,[286][287][288][289][290]. In pyroptosis, the inflammasome is responsible for caspase 5, caspase 4, and caspase 1 activation.…”

Cornerstone Cellular Pathways for Metabolic Disorders and Diabetes Mellitus: Non-Coding RNAs, Wnt Signaling, and AMPK

“…The loss of oxidative defenses that require glutathione during ferroptosis leads to memory loss [8,122,232], neuronal and glial cell dysfunction [59,172,400], cardiac impairment [2,403], osteoarthritis [233], and disorders in the tissue of the breast [169]. Pyroptosis, which can work in conjunction with necroptosis and apoptosis [41, 59,269,304,404,405], leads to inflammatory cell activation, inflammasome generation, and caspase 4, caspase 5, and caspase 1 activation [8,221,311,404,[406][407][408][409]. As a result of excessive cytokine release during pyroptosis [304,405], immune system activity is affected [409] and loss in cognitive function can occur [13,17,22,55,132,163,172,410,411].…”