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Transcriptomic profile of multiple sclerosis patients treated with dimethyl fumarate and their age and sex-matched healthy controls

ABSTRACT: Dimethyl fumarate (DMF) is an immunomodulatory drug approved for the therapy of multiple sclerosis (MS). The identification of response biomarkers to DMF is a necessity in the clinical practice. With this aim, we studied the transcriptomic changes produced by DMF in peripheral blood mononuclear cells (PBMCs) and its association with clinical response. DMF induced a mild transcriptional effect, with only 328 differentially expressed genes (DEGs) after 12 months of treatment. The overall effect was a downregulation of pro-inflammatory genes, chemokines, and activators of the NF-kB pathway. At baseline, no DEGs were found between responders and non-responders. During DMF treatment a differential transcriptomic response was observed, with responders presenting a higher number of DEGs (902 genes) compared to non-responders (189 genes). Responder patients to DMF exhibit a distinguishable transcriptomic response compared to non-responders that should be further studied for the validation of biomarkers of treatment response to DMF.

ORGANISM(S): Homo sapiens

PROVIDER: GSE235357 | GEO | 2023/08/08

REPOSITORIES: GEO

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Project description:The fumarate ester dimethyl fumarate (DMF) has been introduced recently for the treatment of relapsing remitting multiple sclerosis (RRMS), a chronic inflammatory condition resulting in neuronal demyelination and axonal loss. The complete mechanism of DMF action is unknown, but involves the depletion of intracellular glutathione and modification of thiols on Kelch-like ECH-associated protein 1 (Keap1), which in turn induces the expression of antioxidant response element genes. Previous work by our laboratory has shown that DMF reacts with a wide range of protein thiols in adipocytes, detected following ester hydrolysis by an antibody recognizing succinated proteins. We proposed that other intracellular thiol residues may also be irreversibly modified by DMF in neurons and astrocytes. DMF treatment of primary rodent neurons and astrocytes, as well as differentiated N1E-115 cells, resulted in the modification of 24 novel target proteins by mass spectrometry. Using this approach, we confirmed the identification and site of modification of the identified proteins, which include cofilin-1, tubulin and collapsin response mediator protein 2 (CRMP2). An in vitro functional assay that measures the ability of cofilin-1 to sever the actin cytoskeleton demonstrated that DMF-modified cofilin-1 loses activity and generates less monomeric actin, potentially inhibiting cofilin’s cytoskeletal remodeling activity; an effect that could be beneficial in the modulation of myelination during RRMS. DMF modification of tubulin did not significantly impact axonal lysosomal trafficking. The oxygen consumption rate of N1E-115 neurons and the levels of proteins related to mitochondrial energy production were only slightly affected by the highest doses of DMF, confirming that DMF treatment does not impair cellular respiratory function. In summary, we demonstrate that in addition to the stimulation of the antioxidant response, DMF resulted in electrophilic modification of novel protein targets that provide new insight on the mechanisms supporting the neuroprotective and re-myelination benefits associated with DMF treatment.

Project description:Pityriasis rubra pilaris (PRP) is a rare inflammatory skin disorder associated with significant patient morbidity. To further characterize the molecular landscape of PRP, we conducted a transcriptomic analysis of epidermis and dermis collected from patients with moderate-to-severe PRP compared to matched healthy controls, on no systemic therapy and then following 24 weeks of treatment with the IL17A inhibitor, ixekizumab. Patients with PRP not only experienced clinical improvements, but also correction of their cutaneous transcriptome dysregulation after therapy. Moreover, those who has >50% improvement in PASI score after treatment demonstrated distinct transcriptomic profiles when compared to those who failed to respond, despite the lack of a discernable phenotypic difference. Pathway enrichment was strongest among DEGs belonging to inflammatory processes for patients with PRP – in particular, enrichment of the Th17 immune response was seen both prior to and following treatment with IL17A inhibition. Positive regulation of natural killer cell chemotaxis was also seen pre- and post-treatment, however, the pathway’s odds of enrichment decreased following treatment in both epidermis and dermis. Additionally, negative regulation of IL-12 production was highly enriched following therapy, suggesting decreased activity of the Th1 axis. Several individual genes of interest similarly displayed marked differential expression by response status. In parallel with their overall normalization in gene expression, responders had a greater normalization toward healthy control skin than non-responders in the Th17 family genes IL17C, IL23A, CCL20, as well as IL36A and IL36F (implicated in pustular psoriasis), Phospholipase A2 group IVD, and the antimicrobial protein S100A7, all of which remained elevated in non-responders. Intriguingly, responders had higher baseline levels of IL17A and IL17F than non-responders. Whereas dermal IL17A/F levels improved in responders, epidermal expression remained high despite the clinical response to IL17A inhibition. In contrast, non-responder IL17A/F epidermal levels normalized and dermal levels were significantly suppressed compared to healthy controls, despite the lack of clinical improvement. This suggests alternative pathways such as specific targeting of IL17C or IL36 may be preferred in some subsets of PRP.

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Transcriptomic profile of multiple sclerosis patients treated with dimethyl fumarate and their age and sex-matched healthy controls

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