Proline-serine-threonine Phosphatase-interacting Protein 1 Research Articles

Stimulation of PSTPIP1 to trigger proinflammatory responses in asymptomatic SARS-CoV-2 infections

BackgroundA hyperinflammatory response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection gravely worsens the clinical progression of coronavirus disease 2019 (COVID-19). Although the undesirable effects of inflammasome activation have been correlated to the severity of COVID-19, the mechanisms of this process in the asymptomatic infection and disease progression have not yet been clearly elucidated. MethodsWe performed strand-specific RNA sequencing in 39 peripheral blood mononuclear cell (PBMC) samples from asymptomatic individuals（n = 10）, symptomatic patients（n = 16） and healthy donors（n = 13）. ResultsDysregulation of pyrin inflammasomes along with the proline-serine-threonine phosphatase-interacting protein 1 (PSTPIP1) gene was identified in SARS-COV-2 infection. Notably, the PSTPIP1 expression level showed a significant negative correlation with an adjacent long-noncoding RNA (lncRNA) RP11-797A18.6 in the asymptomatic individuals compared with the healthy controls. In addition, a decline in the nuclear factor kappa B subunit 1 (NFKB1) gene expression was observed in asymptomatic infection, followed by a rise in the mild and moderate disease stages, suggesting that altered NFKB1 expression and associated proinflammatory signals may trigger a disease progression. ConclusionsOverall, our results indicate that PSTPIP1-dependent pyrin inflammasomes-mediated pyroptosis and NF-κB activation might be potential preventive targets for COVID-19 disease development and progression.

The Effect of Anti-Inflammatory Drugs on MEFV, PSTPIP1, Siva, and ASC Gene Expression Levels

Aim: Familial Mediterranean Fever (FMF) is the one of the most common autoinflammatory diseases. FMF is characterized by fever attacks and inflammation and colchicine treatment reduces the frequency and severity of FMF attacks. The FMF gene, MEditerranean FeVer (MEFV), encodes a protein called Pyrin, which regulates inflammation through its interactions with several proteins. These proteins are; Apoptosis-associated speck like protein with a CARD (ASC), Proline serine threonine phosphatase interacting protein 1 (PSTPIP1), 14.3.3 proteins and Siva proteins. In this study, we aimed to study the effect of anti-inflammatory drugs with different mechanisms of action on MEFV, PSTPIP1, Siva, and ASC gene expression levels. 
 Material and Methods: We used differentiated monocytic cell line called THP-1 cells. Cells treated with colchicine, naproxen, prednol-L, acetylsalicylic acid, or azathioprine w and w/o lipopolysaccharide (LPS). After incubation, quantitative RT-PCR (qRT-PCR) was performed to measure MEFV, PSTPIP1, Siva, and ASC gene expression levels. 
 Results: MEFV gene expression level was down regulated in colchicine, naproxen, and azathioprine treated cells whereas PSTPIP1 gene expression level was down regulated in naproxen and azathioprine treated cells with LPS. Siva gene expression level was up regulated in all treatments although ASC gene expression level was up regulated in only prednol-L treated cells with LPS.
 Conclusion: These anti-inflammatory drugs are known to have different mechanisms of action however they are all used to treat pain or inflammation. Since Pyrin, PSTPIP1, Siva, and ASC have pro and anti-inflammatory roles, the results showing an alteration in gene expression levels with specific drugs may indicate the possible mechanisms of therapeutic action.

PAPA like Syndrome Associated with Takayasu Arteritis Responding to Corticosteroids: A Case Report

Pyoderma gangrenosum, pyogenic sterile arthritis and acne (PAPA syndrome) is a hereditary, autosomal dominant, auto- inflammatory disease caused by missense mutation in the proline/serine/threonine phosphatase-interacting protein 1 (PSTPIP1) gene and predominantly affecting the joints and skin. Many reports now suggest that the clinical phenotype of PAPA syndrome may vary among people carrying the mutation and can lack the classic triad of pyogenic sterile arthritis, Pyoderma gangrenosum and cystic acne. No definite treatment strategy has been established for this PAPA like syndrome so far. We describe the treatment response of corticosteroids in a 23-year-old male with PAPA like syndrome and Takayasu arteritis, an association which has never been reported before.

PAPA spectrum disorders.

Pyogenic arthritis, pyoderma gangrenosum (PG) and acne (PAPA) syndrome is an autosomal dominant autoinflammatory syndrome due to mutations in proline-serine-threonine phosphatase interacting protein 1 (PSTPIP1) gene and presenting with cutaneous and articular manifestations. Other autoinflammatory syndromes caused by mutations in PSTPIP1 gene or characterized by clinical findings overlapping with those found in PAPA syndrome have been recently included in the group of PAPA spectrum disorders. These disorders are PASH (PG, acne and hidradenitis suppurativa [HS]), PAPASH (PASH associated with pyogenic sterile arthritis), PsAPASH (PASH combined with psoriatic arthritis [PsA], PASS (PG, acne, ankylosing spondylitis, with or without HS), PAC (PG, acne and ulcerative colitis [UC]) and PAMI syndrome (PSTPIP1-associated myeloid-related-proteinemia inflammatory syndrome). Except for PAPA and PAMI, no specific pathogenetic mutations have been identified in these syndromes. Dermatologists should be aware that PG, acne and HS may represent cutaneous signs hiding the presence of these rare entities. Systemic corticosteroids, a number of immunosuppressants and biologics, such as interleukin (IL)-1 antagonists and tumour necrosis factor (TNF) α inhibitors, are nowadays therapy for these diseases. A pathogenesis-driven treatment is the near future in the management of these conditions.

Additive Effects of Zinc Chloride on the Suppression of Hepatitis A Virus Replication by Interferon in Human Hepatoma Huh7 Cells.

Hepatitis A virus (HAV) infection is still one of the serious health problems worldwide, despite the existence of effective vaccines for HAV. Zinc compounds have antiviral activities against various DNA and RNA viruses. Therefore, we investigated the effects of zinc compounds on the antiviral activity of interferon against HAV. The effects of zinc compounds with or without interferon on HAV genotype IIIA HA11-1299 replication were examined in human hepatoma Huh7 cells. Cell viability was examined by the MTS assay. Inflammasome associated gene expression was examined by real-time reverse transcription-polymerase chain reaction. Both zinc sulfate and zinc chloride had an inhibitory effect on HAV replication. Zinc sulfate tended to enhance while zinc chloride significantly enhanced the anti-HAV effect induced by interferon-alpha-2a. Zinc chloride significantly up-regulated mitogen-activated protein kinase 12 (MAPK12) and down-regulated 6 related genes [baculoviral IAP repeat containing 3 (BIRC3), interleukin 1 beta (IL1B), proline-serine-threonine phosphatase interacting protein 1 (PSTPIP1), prostaglandin-endoperoxide synthase 2 (PTGS2), PYD and CARD domain containing (PYCARD), and tumor necrosis factor (TNF)]. Zinc chloride inhibits HAV replication and has additive effects on the anti-HAV activities of interferon.

Proline-serine-threonine phosphatase interacting protein 1 (PSTPIP1) controls immune synapse stability in human T cells

Proline-serine-threonine phosphatase interacting protein 1 (PSTPIP1) is a cytosolic adaptor protein involved with T-cell activation, differentiation, and migration. On cognate T-cell contact, PSTPIP1 is recruited to surface-expressed CD2, where it regulates F-actin remodeling. An immune synapse (IS) is thereby rapidly formed, consisting of T-cell receptor clusters surrounded by a ring of adhesion molecules, including CD2. From genetic screening of patients with primary immunodeficiencies, we identified 2 mutations in PSTPIP1, R228C and T274M, which we further characterized in the primary patients' T cells. F-actin dynamics were assessed in primary T cells from the patients and control subjects by using fluorescence-activated cell sorting. HEK293T and Jurkat cells were transfected with R228C, T274M, and wild-type PSTPIP1 to visualize F-actin in IS formation. CD2-PSTPIP1 association was quantified through immunoprecipitation assays. The patients presented with immunodeficiency without signs of autoinflammation. The patient with the R228C mutation had expansion of mostly naive phenotype T cells and few memory T cells; the patient with the T274M mutation had 75% reduction in CD4 T cells that were predominantly of the memory subset. We observed F-actin polymerization defects in T cells from both patients with PSTPIP1, most notably the patient with the T274M mutation. Capping of CD2-containing membrane microdomains was disrupted. Analysis of IS formation using Jurkat T-cell transfectants revealed a reduction in F-actin accumulation at the IS, again especially in cells from the patient with the T274M PSTPIP1 mutation. T cells from the patient with the T274M mutation migrated spontaneously at increased speed, as assessed in a 3-dimensional collagen matrix, whereas T-cell receptor cross-linking induced a significantly diminished calcium flux. We propose that PSTPIP1 T-cell differentiation defects are caused by defective control of F-actin polymerization. Apreactivated polymerized F-actin status, as seen in T cells from patients with the PSTPIP1 T274M mutation, appears particularly damaging. PSTPIP1 controls IS formation and cell adhesion through its function as an orchestrator of the F-actin cytoskeleton.

PASH syndrome (pyoderma gangrenosum, acne and hidradenitis suppurativa): a disease with genetic heterogeneity

PASH syndrome is a clinical entity associating pyoderma gangrenosum (PG), severe acne and hidradenitis suppurativa (HS)1. Absence of pyogenic sterile arthritis (PA) distinguishes PASH syndrome from PAPASH and PAPA syndromes which associate PA in combination with PG, severe acne with or without HS, respectively2,3. Mutations in PSTPIP1 (proline-serine-threonine-phosphatase interacting protein 1) gene were identified in patients with PAPA and PAPASH syndromes, although genetic heterogeneity was observed in PAPA syndrome2,3. Loss-of-function mutations in the y-secretase genes, Nicastrin (NCSTN), Presenilin Enhancer-2 (PSENEN), and Presenilin-1 (PSEN1), have been reported in a small proportion of HS patients4,5. This article is protected by copyright. All rights reserved.

Alarming consequences - autoinflammatory disease spectrum due to mutations in proline-serine-threonine phosphatase-interacting protein 1.

To give an overview about the expanding spectrum of autoinflammatory diseases due to mutations in proline-serine-threonine phosphatase-interacting protein 1 (PSTPIP1) and new insights into their pathogenesis. In addition to classical pyogenic sterile arthritis, pyoderma gangrenosum, and acne (PAPA) syndrome, PSTPIP1-associated myeloid-related proteinemia inflammatory (PAMI) syndrome has been described as a distinct clinical phenotype of PSTPIP1-associated inflammatory diseases (PAID) and other entities are emerging. In addition to dysregulation of IL-1ß release from activated PAPA monocytes that requires NLR family, pyrin domain containing 3 (NLRP3), PSTPIP1 mutations have an general impact on cellular dynamics of cells of the innate immune system. In addition, overwhelming expression and release of the alarmins myeloid-related protein (MRP) 8 and 14 by activated phagocytes and keratinocytes, which promote innate immune mechanisms in a Toll like receptor (TLR) 4-dependent manner, are a characteristic feature of these diseases and form a positive feed-back mechanism with IL-1ß. Autoinflammatory diseases due to PSTPIP1 mutations are not restricted to the classical PAPA phenotype but might present with other distinct clinical features. MRP8/14 serum levels are a hallmark of PAPA and PAMI and can be used as screening tool to initiate targeted genetic testing in suspected cases. The feedback mechanism of IL-1ß and MRP-alarmin release may offer novel targets for future therapeutic approaches.

The Relationship between NALP3 and Autoinflammatory Syndromes.

The nucleotide-binding domain, leucine-rich repeat/pyrin domain-containing-3 (NALP3) inflammasome, which is required for synthesis of interleukin-1β, has been implicated in the pathogenesis of several autoinflammatory syndromes. This review of the literature summarizes the interconnectedness of NALP3 inflammasome with some of these disorders. Familial Mediterranean fever results from a mutation in the Mediterranean fever (MEFV) gene, which encodes the pyrin protein. Previous study results suggest that pyrin suppresses caspase-1 activation, perhaps by competing for the adaptor protein, termed, pyrin domain of apoptosis/speck-like protein containing a caspase-recruitment domain (ACS) which therefore interferes with NALP3 inflammasome activation. The nucleotide-binding domain, leucine-rich repeat/pyrin domain-containing-3 (NALP3) inflammasome is constitutively activated in cryopyrin-associated periodic syndromes due to gain-of-function mutations resulting from point mutations within the neuronal apoptosis inhibitor protein/class 2 transcription factor/heterokaryon incompatibility/telomerase-associated protein-1 (NACHT) domain of the NALP3 protein. Pyogenic arthritis, pyoderma gangrenosum and acne (PAPA) syndrome is caused by mutations in the genes encoding proline-serine-threonine phosphatase interacting protein 1 (PSTPIP1). These PSTPIP1 mutants are thought to bind to pyrin causing an increase in the pyrin domain of apoptosis/speck-like protein containing a caspase-recruitment domain (ASC) pyroptosome assembly leading to procaspase-1 recruitment and therefore its activation. Hyperimmunoglublinemia D syndrome is caused by mevalonate kinase (MVK) deficiency, which may be affected by protein accumulation that leads to NALP3 inflammasome activation. Tumor necrosis factor receptor–associated periodic syndrome is associated with mutations in the tumor necrosis factor receptor superfamily, member 1A (TNFRSF1A) gene which decreases the level of soluble tumor necrosis factor receptor-1 (TNFR1) leading to neutralization of tumor necrosis factor (TNF)-α. In general, these autoinflammatory disorders have shown a clinical response to interleukin-1 (IL-1) antagonists, suggesting that the NALP3 inflammasome serves a critical role in their pathogenesis.

Pyrin-PSTPIP1 colocalises at the leading edge during cell migration.

A set of mutations in the MEditerranean FeVer (MEFV) gene causes familial Mediterranean fever (FMF), the most common auto-inflammatory disease. The gene encodes a protein named pyrin, which appears to play an important role in inflammatory pathways. Furthermore, pyrin, which is expressed in neutrophils, has been reported to interact with proline-serine-threonine phosphatase-interacting protein 1 (PSTPIP1) and actin proteins. However, the relations between pyrin and PSTPIP1 during the cell migration have not yet been elucidated. In the present study, we constructed a cell migration assay method using HL-60 cells. Pyrin-PSTPIP1 interactions were analysed by immunofluorescence staining in control, differentiated and differentiated-stimulated HL-60 cells. In stimulated cells, pyrin-polymerised actin, PSTPIP1-polymerised actin and pyrin-PSTPIP1 were found to be colocalised. Pyrin has been shown to be colocalised with actin and PSTPIP1 at the leading edge of the migrating cell. For the first time, PSTPIP1 was found to interact with dynamic actin and pyrin at the site of polarisation.

Single amino acid charge switch defines clinically distinct proline-serine-threonine phosphatase-interacting protein 1 (PSTPIP1)–associated inflammatory diseases

Hyperzincemia and hypercalprotectinemia (Hz/Hc) is a distinct autoinflammatory entity involving extremely high serum concentrations of the proinflammatory alarmin myeloid-related protein (MRP) 8/14 (S100A8/S100A9 and calprotectin). We sought to characterize the genetic cause and clinical spectrum of Hz/Hc. Proline-serine-threonine phosphatase-interacting protein 1 (PSTPIP1) gene sequencing was performed in 14 patients with Hz/Hc, and their clinical phenotype was compared with that of 11 patients with pyogenic arthritis, pyoderma gangrenosum, and acne (PAPA) syndrome. PSTPIP1-pyrin interactions were analyzed by means of immunoprecipitation and Western blotting. A structural model of the PSTPIP1 dimer was generated. Cytokine profiles were analyzed by using the multiplex immunoassay, and MRP8/14 serum concentrations were analyzed by using an ELISA. Thirteen patients were heterozygous for a missense mutation in the PSTPIP1 gene, resulting in a p.E250K mutation, and 1 carried a mutation resulting in p.E257K. Both mutations substantially alter the electrostatic potential of the PSTPIP1 dimer model in a region critical for protein-protein interaction. Patients with Hz/Hc have extremely high MRP8/14 concentrations (2045 ± 1300 μg/mL) compared with those with PAPA syndrome (116 ± 74 μg/mL) and have a distinct clinical phenotype. A specific cytokine profile is associated with Hz/Hc. Hz/Hc mutations altered protein binding of PSTPIP1, increasing interaction with pyrin through phosphorylation of PSTPIP1. Mutations resulting in charge reversal in the y-domain of PSTPIP1 (E→K) and increased interaction with pyrin cause a distinct autoinflammatory disorder defined by clinical and biochemical features not found in patients with PAPA syndrome, indicating a unique genotype-phenotype correlation for mutations in the PSTPIP1 gene. This is the first inborn autoinflammatory syndrome in which inflammation is driven by uncontrolled release of members of the alarmin family.

Genome-wide association study of recalcitrant atopic dermatitis in Korean children

Atopic dermatitis (AD) is a heterogeneous chronic inflammatory skin disease. Most AD during infancy resolves during childhood, but moderate-to-severe AD with allergic sensitization is more likely to persist into adulthood and more often occurs with other allergic diseases. We sought to find susceptibility loci by performing the first genome-wide association study (GWAS) of AD in Korean children with recalcitrant AD, which was defined as moderate-to-severe AD with allergic sensitization. Our study included 246 children with recalcitrant AD and 551 adult control subjects with a negative history of both allergic disease and allergic sensitization. DNA from these subjects was genotyped; sets of common single nucleotide polymorphisms (SNPs) were imputed and used in the GWAS after quality control checks. SNPs at a region on 13q21.31 were associated with recalcitrant AD at a genome-wide threshold of significance (P< 2.0 × 10(-8)). These associated SNPs are more than 1 Mb from the closest gene, protocadherin (PCDH)9. SNPs at 4 additional loci had P values of less than 1 × 10(-6), including SNPs at or near the neuroblastoma amplified sequence (NBAS; 2p24.3), thymus-expressed molecule involved in selection (THEMIS; 6q22.33), GATA3 (10p14), and S-phase cyclin A-associated protein in the ER (SCAPER; 15q24.3) genes. Further analysis of total serum IgE levels suggested 13q21.31 might be primarily an IgE locus, and analyses of published data demonstrated that SNPs at the 15q24.3 region are expression quantitative trait loci for 2 nearby genes, ISL2 and proline-serine-threonine phosphatase interacting protein 1 (PSTPIP1), in immune cells. Our GWAS of recalcitrant AD identified new susceptibility regions containing genes involved in epithelial cell function and immune dysregulation, 2 key features of AD, and potentially extend our understanding of their role in pathogenesis.

Novel PSTPIP1 gene mutation in a patient with pyogenic arthritis, pyoderma gangrenosum and acne (PAPA) syndrome

IntroductionPyogenic arthritis, pyoderma gangrenosum, and acne (PAPA) syndrome is a rare autosomal dominant disease that usually presents in childhood with recurrent sterile arthritis. As the child ages into puberty, cutaneous features develop and arthritis subsides. We report the case of a now 25-year-old male patient with PAPA syndrome with the E250K mutation in PSTPIP1. We also present a systematic literature review of other PAPA cases. MethodWe conducted a literature search of PubMed using the following search terms: E250K mutation, PSTPIP1, and PAPA. ResultsPAPA syndrome is caused by mutations on chromosome 15q affecting the proline-serine-threonine phosphatase-interacting protein 1 (PSTPIP1) gene, also known as CD2-binding protein 1 (CD2BP1). The reported cases of PAPA syndrome currently in the literature involve mutations in A230T and E250Q. One case of a novel E250K mutation has been reported, which presented with a different phenotype to previously described cases of PAPA syndrome. ConclusionWith variation present between disease presentations from case to case, it is possible that the spectrum of PAPA syndrome is wider than currently thought. Further research is needed which may uncover an as-yet undiscovered genetic abnormality linking these interrelated diseases together.

Imp2, the PSTPIP homolog in fission yeast, affects sensitivity to the immunosuppressant FK506 and membrane trafficking in fission yeast

Cytokinesis is a highly ordered process that divides one cell into two cells, which is functionally linked to the dynamic remodeling of the plasma membrane coordinately with various events such as membrane trafficking. Calcineurin is a highly conserved serine/threonine protein phosphatase, which regulates multiple biological functions, such as membrane trafficking and cytokinesis. Here, we isolated imp2-c3, a mutant allele of the imp2+ gene, encoding a homolog of the mouse PSTPIP1 (proline-serine-threonine phosphatase interacting protein 1), using a genetic screen for mutations that are synthetically lethal with calcineurin deletion in fission yeast. The imp2-c3 mutants showed a defect in cytokinesis with multi-septated phenotypes, which was further enhanced upon treatment with the calcineurin inhibitor FK506. Notably, electron micrographs revealed that the imp2-c3 mutant cells accumulated aberrant multi-lamella Golgi structures and putative post-Golgi secretory vesicles, and exhibited fragmented vacuoles in addition to thickened septa. Consistently, imp2-c3 mutants showed a reduced secretion of acid phosphatase and defects in vacuole fusion. The imp2-c3 mutant cells exhibited a weakened cell wall, similar to the membrane trafficking mutants identified in the same genetic screen such as ypt3-i5. These findings implicate the PSTPIP1 homolog Imp2 in Golgi/vacuole function, thereby affecting various cellular processes, including cytokinesis and cell integrity.

Proline-serine-threonine phosphatase interacting protein1 inhibition of T-cell receptor signaling depends on its SH3 domain.

Proline-serine-threonine phosphatase interacting protein 1 (PSTPIP1) is an adaptor protein associated with the cytoskeleton that is mainly expressed in hematopoietic cells. Mutations in PSTPIP1 cause the rare autoinflammatory disease called pyogenic arthritis, pyoderma gangrenosum, and acne. We carried out this study to further our knowledge on PSTPIP1 function in T cells, particularly in relation to the phosphatase lymphoid phosphatase (LYP), which is involved in several autoimmune diseases. LYP-PSTPIP1 binding occurs through the C-terminal homology domain of LYP and the F-BAR domain of PSTPIP1. PSTPIP1 inhibits T-cell activation upon T-cell receptor (TCR) and CD28 engagement, regardless of CD2 costimulation. This function of PSTPIP1 depends on the presence of an intact SH3 domain rather than on the F-BAR domain, indicating that ligands of the F-BAR domain, such as the PEST phosphatases LYP and PTP-PEST, are not critical for its negative regulatory role in TCR signaling. Additionally, PSTPIP1 mutations that cause the pyogenic arthritis, pyoderma gangrenosum and acne syndrome do not affect PSTPIP1 function in T-cell activation through the TCR.

OP0128 The Regulation of MRP8/14 in Pstpip1-Associated Myeloid-Related-Proteinaemia Inflammatory Syndrome (PAMI)

BackgroundMRP8 and MRP14 are phagocyte-derived Damage Associated Molecular Pattern (DAMP) proteins and can be used as biomarkers in inflammatory diseases e.g. juvenile idiopathic arthritis. We found that the MRP8/14 complex...

PW02-006 - PAPA syndrome clinical spectrum and IL1B release

Pyogenic sterile Arthritis Pyoderma gangrenosum and Acne (PAPA) syndrome is a rare autosomal dominant inherited autoinflammatory disease caused by mutations in Proline-serine-threonine phosphatase-interacting protein 1 (PSTPIP1). In childhood, the syndrome is featured by recurrent sterile, erosive arthritis, potentially leading to joint destruction. By puberty, cutaneous symptoms become predominant, with recurrent onset of pathergy, abscesses, severe cystic acne, and pyoderma gangrenosum. Typically, both articular and cutaneous outcomes occur following a minor trauma. PSTPIP1 may interact with NLRP3 and caspase-1 but a clear involvement of IL-1β is still controversial. While anti-IL1 treatment seems to be effective on joint manifestations, IL inhibition does not display the same effectiveness in the management of skin lesions.

OP0024 The Function of PSTPIP1 and S100A8/S100A9 in Hyperzincaemia & Hypercalprotectinaemia and the PAPA-Syndrom

BackgroundHypercalprotectinaemia and hyperzincaemia is a very rare autoinflammatory syndrome that is characterized by excessively high S100A8/S100A9 complex (calprotectin) serum concentrations (0.9-12.0 g/l, normal range < 0.001 g/l) not present in...

Inflammation in Mice Ectopically Expressing Human Pyogenic Arthritis, Pyoderma Gangrenosum, and Acne (PAPA) Syndrome-associated PSTPIP1 A230T Mutant Proteins

Pyogenic Arthritis, Pyoderma Gangrenosum, and Acne Syndrome (PAPA syndrome) is an autoinflammatory disease caused by aberrant production of the proinflammatory cytokine interleukin-1. Mutations in the gene encoding proline serine threonine phosphatase-interacting protein-1 (PSTPIP1) have been linked to PAPA syndrome. PSTPIP1 is an adaptor protein that interacts with PYRIN, the protein encoded by the Mediterranean Fever (MEFV) gene whose mutations cause Familial Mediterranean Fever (FMF). However, the pathophysiological function of PSTPIP1 remains to be elucidated. We have generated mouse strains that either are PSTPIP1 deficient or ectopically express mutant PSTPIP1. Results from analyzing these mice suggested that PSTPIP1 is not an essential regulator of the Nlrp3, Aim2, or Nlrc4 inflammasomes. Although common features of human PAPA syndrome such as pyogenic arthritis and skin inflammation were not recapitulated in the mouse model, ectopic expression of the mutant but not the wild type PSTPIP1 in mice lead to partial embryonic lethality, growth retardation, and elevated level of circulating proinflammatory cytokines.

Clinical features and functional significance of the P369S/R408Q variant in pyrin, the familial Mediterranean fever protein

ObjectivesFamilial Mediterranean fever (FMF) is caused by mutations in MEFV, which encodes pyrin. The nature of substitutions P369S and R408Q in exon 3 remains unclear. Exon 3 encoding pyrin's B-box...