Dataset Information

Functional diversity of NLRP3 gain-of-function mutants associated with CAPS autoinflammation.

ABSTRACT: NLRP3-associated autoinflammatory disease is a heterogenous group of monogenic conditions caused by NLRP3 gain-of-function mutations. The poor functional characterization of most NLRP3 variants hinders diagnosis despite efficient anti-IL-1 treatments. Additionally, while NLRP3 is controlled by priming and activation signals, gain-of-functions have only been investigated in response to priming. Here, we characterize 34 NLRP3 variants in vitro, evaluating their activity upon induction, priming, and/or activation signals, and their sensitivity to four inhibitors. We highlight the functional diversity of the gain-of-function mutants and describe four groups based on the signals governing their activation, correlating partly with the symptom severity. We identify a new group of NLRP3 mutants responding to the activation signal without priming, associated with frequent misdiagnoses. Our results identify key NLRP3 residues controlling inflammasome activity and sensitivity to inhibitors, and antagonistic mechanisms with broader efficacy for therapeutic strategies. They provide new insights into NLRP3 activation, an explanatory mechanism for NLRP3-AID heterogeneity, and original tools for NLRP3-AID diagnosis and drug development.

SUBMITTER: Cosson C

PROVIDER: S-EPMC10966137 | biostudies-literature | 2024 May

REPOSITORIES: biostudies-literature

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Functional diversity of NLRP3 gain-of-function mutants associated with CAPS autoinflammation.

Cosson Camille C Riou Romane R Patoli Danish D Niu Tingting T Rey Amaury A Groslambert Marine M De Rosny Charlotte C Chatre Elodie E Allatif Omran O Henry Thomas T Venet Fabienne F Milhavet Florian F Boursier Guilaine G Belot Alexandre A Jamilloux Yvan Y Merlin Etienne E Duquesne Agnès A Grateau Gilles G Savey Léa L Jacques Maria Alexandre Thibault AT Pagnier Anne A Poutrel Solène S Lambotte Olivier O Mallebranche Coralie C Ardois Samuel S Richer Olivier O Lemelle Irène I Rieux-Laucat Frédéric F Bader-Meunier Brigitte B Amoura Zahir Z Melki Isabelle I Cuisset Laurence L Touitou Isabelle I Geyer Matthias M Georgin-Lavialle Sophie S Py Bénédicte F BF

The Journal of experimental medicine 20240326 5

NLRP3-associated autoinflammatory disease is a heterogenous group of monogenic conditions caused by NLRP3 gain-of-function mutations. The poor functional characterization of most NLRP3 variants hinders diagnosis despite efficient anti-IL-1 treatments. Additionally, while NLRP3 is controlled by priming and activation signals, gain-of-functions have only been investigated in response to priming. Here, we characterize 34 NLRP3 variants in vitro, evaluating their activity upon induction, priming, an ...[more]

PMID: 38530241

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Project description:BACKGROUND:X-linked protoporphyria (XLP) (MIM 300752) is an erythropoietic porphyria due to gain-of-function mutations in the last exon (Ducamp et al., Hum Mol Genet 22:1280-88, 2013) of the erythroid-specific aminolevulinate synthase gene (ALAS2). Five ALAS2 exon 11 variants identified by the NHBLI Exome sequencing project (p.R559H, p.E565D, p.R572C, p.S573F and p.Y586F) were expressed, purified and characterized in order to assess their possible contribution to XLP. To further characterize the XLP gain-of-function region, five novel ALAS2 truncation mutations (p.P561X, p.V562X, p.H563X, p.E569X and p.F575X) were also expressed and studied. METHODS:Site-directed mutagenesis was used to generate ALAS2 mutant clones and all were prokaryotically expressed, purified to near homogeneity and characterized by protein and enzyme kinetic assays. Standard deviations were calculated for 3 or more assay replicates. RESULTS:The five ALAS2 single nucleotide variants had from 1.3- to 1.9-fold increases in succinyl-CoA Vmax and 2- to 3-fold increases in thermostability suggesting that most could be gain-of-function modifiers of porphyria instead of causes. One SNP (p.R559H) had markedly low purification yield indicating enzyme instability as the likely cause for XLSA in an elderly patient with x-linked sideroblastic anemia. The five novel ALAS2 truncation mutations had increased Vmax values for both succinyl-CoA and glycine substrates (1.4 to 5.6-fold over wild-type), while the Kms for both substrates were only modestly changed. Of interest, the thermostabilities of the truncated ALAS2 mutants were significantly lower than wild-type, with an inverse relationship to Vmax fold-increase. CONCLUSIONS:Patients with porphyrias should always be assessed for the presence of the ALAS2 gain-of-function modifier variants identified here. A key region of the ALAS2 carboxyterminal region is identified by the truncation mutations studied here and the correlation of increased thermolability with activity suggests that increased molecular flexibility/active site openness is the mechanism of enhanced function of mutations in this region providing further insights into the role of the carboxyl-terminal region of ALAS2 in the regulation of erythroid heme synthesis.

Project description:Comparison between transcriptomes of dash mutants vs WT plants and ectopic expression of 35S::DASH in hairy roots versus empty vector Loss of function: 3 WT plants A17 at 8 days after pollination and 3 dash mutant plants at 8 days afer pollination. Gain of function transformants: 3 transformed plants containing empty vector and 4 transformed plants containing 35S::DASH Total RNA was extracted using a modified cetyltrimethylammonium bromide method (Verdier et al., 2008). 5ug of total RNA from each sample was purified (RNeasy MinElute Cleanup kit; Qiagen) according to the manufacturer?s instructions. RNA was quantified and evaluated for purity using an ND-1000 Nanodrop Spectrophotometer (NanoDrop Technologies) and a Bioanalyzer 2100 (Agilent). The Affymetrix M. truncatula GeneChip Array (Affymetrix) was used for expression analysis during seed development. RNA from three (for dash mutant analysis) and four (for DASH ectopic expression analysis) independent biological replicates were analysed for each time point. Probe synthesis/labelling was carried out from 500 ng of RNA using the GeneChip 3?IVT express kit, according to the manufacturer?s instructions (Affymetrix). Array hybridization, scanning, and data normalization were performed as described by Benedito et al., (2008). Each file from the hybridized Affymetrix array was exported from GeneChip Operating Software version 1.4 (Affymetrix) and imported into Robust Multiarray Average Express (Irizarry et al., 2003) for global normalization. Presence/absence call for each probe set to remove background noise was obtained using dCHIP (Li and Wong, 2001). To identify probe sets differentially expressed in dash mutant vs WT control, the R package Anapuce (J. Aubert, UMR 518 AgroParisTech/INRA) was used. For each probe set, a paired t-test was performed on the log2 expression data from three arrays (3 independent biological repeats for 8 dap data), assuming that the variance of the log expression was the same for all transcripts per genotype. Spots with extreme specific variance, too low or too high, were excluded from the statistical analysis (details on the procedure given in Gagnot et al., 2008). P-values were adjusted by the Benjamini-Hochberg method (Benjamini and Hochberg, 1995), which controls the family-wise error rate.

Project description:The majority of TP53 missense mutations identified in cancer patients are in the DNA-binding domain and are characterized as either structural or contact mutations. These missense mutations exhibit inhibitory effects on wild-type p53 activity. More importantly, these mutations also demonstrate gain-of-function (GOF) activities characterized by increased metastasis, poor prognosis, and drug resistance. To better understand the activities by which TP53 mutations, identified in Li-Fraumeni syndrome, contribute to tumorigenesis, we generated mice harboring a novel germline Trp53R245W allele (contact mutation) and compared them with existing models with Trp53R172H (structural mutation) and Trp53R270H (contact mutation) alleles. Thymocytes from heterozygous mice showed that all three hotspot mutations exhibited similar inhibitory effects on wild-type p53 transcription in vivo, and tumors from these mice had similar levels of loss of heterozygosity. However, the overall survival of Trp53R245W/+ and Trp53R270H/+ mice, but not Trp53R172H/+ mice, was significantly shorter than that of Trp53+/- mice, providing strong evidence for p53-mutant-specific GOF contributions to tumor development. Furthermore, Trp53R245W/+ and Trp53R270H/+ mice had more osteosarcoma metastases than Trp53R172H/+ mice, suggesting that these two contact mutants have stronger GOF in driving osteosarcoma metastasis. Transcriptomic analyses using RNA sequencing data from Trp53R172H/+, Trp53R245W/+, and Trp53R270H/+ primary osteosarcomas in comparison with Trp53+/- indicated that GOF of the three mutants was mediated by distinct pathways. Thus, both the inhibitory effect of mutant over wild-type p53 and GOF activities of mutant p53 contributed to tumorigenesis in vivo. Targeting p53 mutant-specific pathways may be important for therapeutic outcomes in osteosarcoma.Significancep53 hotspot mutants inhibit wild-type p53 similarly but differ in their GOF activities, with stronger tumor-promoting activity in contact mutants and distinct protein partners of each mutant driving tumorigenesis and metastasis.

Project description:BackgroundCryopyrin-associated periodic syndrome (CAPS) is an inherited autoinflammatory disease caused by a gain-of-function mutation in NLRP3. Although CAPS patients frequently suffer from sensorineural hearing loss, it remains unclear whether CAPS-associated mutation in NLRP3 is associated with the progression of hearing loss.MethodsWe generated a mice with conditional expression of CAPS-associated NLRP3 mutant (D301N) in cochlea-resident CX3CR1 macrophages and examined the susceptibility of CAPS mice to inflammation-mediated hearing loss in a local and systemic inflammation context.FindingsUpon lipopolysaccharide (LPS) injection into middle ear cavity, NLRP3 mutant mice exhibited severe cochlear inflammation, inflammasome activation and hearing loss. However, this middle ear injection model induced a considerable hearing loss in control mice and inevitably caused an inflammation-independent hearing loss possibly due to ear tissue damages by injection procedure. Subsequently, we optimized a systemic LPS injection model, which induced a significant hearing loss in NLRP3 mutant mice but not in control mice. Peripheral inflammation induced by a repetitive low dose of LPS injection caused a blood-labyrinth barrier disruption, macrophage infiltration into cochlea and cochlear inflammasome activation in an NLRP3-dependent manner. Interestingly, both cochlea-infiltrating and -resident macrophages contribute to peripheral inflammation-mediated hearing loss of CAPS mice. Furthermore, NLRP3-specific inhibitor, MCC950, as well as an interleukin-1 receptor antagonist significantly alleviated systemic LPS-induced hearing loss and inflammatory phenotypes in NLRP3 mutant mice.InterpretationOur findings reveal that CAPS-associated NLRP3 mutation is critical for peripheral inflammation-induced hearing loss in our CAPS mice model, and an NLRP3-specific inhibitor can be used to treat inflammation-mediated sensorineural hearing loss.FundingNational Research Foundation of Korea Grant funded by the Korean Government and the Team Science Award of Yonsei University College of Medicine.

Dataset Information

Functional diversity of NLRP3 gain-of-function mutants associated with CAPS autoinflammation.

Publications

Functional diversity of NLRP3 gain-of-function mutants associated with CAPS autoinflammation.

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