Banu Balci-Peynircioglu

Pyrin Modulates the Intracellular Distribution of PSTPIP1

PSTPIP1 is a cytoskeleton-associated adaptor protein that links PEST-type phosphatases to their substrates. Mutations in PSTPIP1 cause PAPA syndrome (Pyogenic sterile Arthritis, Pyoderma gangrenosum, and Acne), an autoinflammatory disease. PSTPIP1 binds to pyrin and mutations in pyrin result in familial Mediterranean fever (FMF), a related autoinflammatory disorder. Since disease-associated mutations in PSTPIP1 enhance pyrin binding, PAPA syndrome and FMF are thought to share a common pathoetiology. The studies outlined here describe several new aspects of PSTPIP1 and pyrin biology. We document that PSTPIP1, which has homology to membrane-deforming BAR proteins, forms homodimers and generates membrane-associated filaments in native and transfected cells. An extended FCH (Fes-Cip4 homology) domain in PSTPIP1 is necessary and sufficient for its self-aggregation. We further show that the PSTPIP1 filament network is dependent upon an intact tubulin cytoskeleton and that the distribution of this network can be modulated by pyrin, indicating that this is a dynamic structure. Finally, we demonstrate that pyrin can recruit PSTPIP1 into aggregations (specks) of ASC, another pyrin binding protein. ASC specks are associated with inflammasome activity. PSTPIP1 molecules with PAPA-associated mutations are recruited by pyrin to ASC specks with particularly high efficiency, suggesting a unique mechanism underlying the robust inflammatory phenotype of PAPA syndrome.

The effect of colchicine on pyrin and pyrin interacting proteins.

MEFV which encodes pyrin, cause familial Mediterranean fever (FMF), the most common auto‐inflammatory disease. Pyrin is believed to be a regulator of inflammation, though the nature of this regulatory activity remains to be identified. Prophylactic treatment with colchicine, a microtubule toxin, has had a remarkable effect on disease progression and outcome. It has been thought that, inhibition of microtubule polymerization is the main mechanism of action of colchicine. But, the exact cellular mechanism explaining the efficacy of colchicine in suppressing FMF attacks is still unclear. Given the ability of colchicine treatment to be considered as a differential diagnosis criteria of FMF, we hypothesized that colchicine may have a specific effect on pyrin and pyrin interacting proteins. This study showed that colchicine prevents reticulated fibrils formed by PSTPIP1 filaments and reduces ASC speck rates in transfected cells. We further noted that, colchicine down‐regulates MEFV expression in THP‐1 cells. We also observed that colchicine causes re‐organization of actin cytoskeleton in THP‐1 cells. Pyrin is an actin‐binding protein that specifically localizes with polymerizing actin filaments. Thus, MEFV expression might be affected by re‐organization of actin cytoskeleton. The data presented here reveal an important connection between colchicine and pyrin which might explain the remarkable efficacy of colchicine in preventing FMF attacks. J. Cell. Biochem. 113: 3536–3546, 2012.

Pyrin, Product of the MEFV Locus, Interacts With the Proapoptotic Protein, Siva

Mutations in pyrin cause the autoinflammatory disorder familial Mediterranean fever (FMF), a syndrome characterized by sporadic and unpredictable attacks of fever and localized severe pain. Currently, it is not clear how attacks are triggered, nor why they spontaneously resolve after 2 or 3 days. In fact, the cellular function of the pyrin protein and the molecular underpinnings of its malfunction in FMF have so far eluded clear definition. The identification of pyrin‐interacting proteins has the potential to increase our understanding of the cellular networks in which pyrin functions. Previous reports have established that pyrin interacts with the apoptotic protein ASC, the cytoskeletal adaptor protein PSTPIP1, the inflammatory caspase, Caspase‐1 and certain forms of the cytosolic anchoring protein 14‐3‐3. Here, we report that pyrin also interacts with Siva, a pro‐apoptotic protein first identified for its interaction with the cytosolic tail of CD27, a TNF family receptor. The interaction between pyrin and Siva involves the C‐terminal B30.2/rfp/SRPY domain of pyrin and exon 1 of Siva. We show that Siva and pyrin are indeed co‐expressed in human neutrophils, monocytes, and synovial cells. Furthermore, using a novel protein/protein interaction assay, we demonstrate that pyrin can recruit Siva to ASC specks, establishing a potential platform for intersection of ASC and Siva function. Finally, we show that pyrin modulates the apoptotic response to oxidative stress mediated by Siva. Thus, the Siva–pyrin interaction may be a potential target for future therapeutic strategies. J. Cell. Physiol. 216: 595–602, 2008,

Behçet Disease serum is immunoreactive to neurofilament medium which share common epitopes to bacterial HSP-65, a putative trigger

Autoimmune and dysimmune inflammatory mechanisms on a genetically susceptible background are implicated in the etiology of Behçets Disease (BD). Heat-shock protein-65 (HSP-65) derived from Streptococcus sanguinis was proposed as a triggering factor based on its homology with human HSP-60. However, none of the autoantigens identified so far in sera from BD share common epitopes with bacterial HSP-65 or has a high prevalence. Here, we report that sera from BD patients are immunoreactive against filamentous neuronal processes in the mouse brain, retina and scrotal skin in great majority of patients. By using matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) and peptide mass fingerprinting, Western blotting and peptide blocking experiments, we have identified neurofilament medium (NF-M) as the probable antigen for the serologic response observed. Clustal Omega analyses detected significant structural homology between the human NF-M and bacterial HSP-65 corresponding to amino acids 111-126, 213-232 and 304-363 of mycobacterial HSP-65, which were previously identified to induce proliferation of lymphocytes obtained from BD patients. We also found that sera immunoreactive against NF-M cross-reacted with bacterial HSP-65. These findings suggest that NF-M may be involved in autoimmunity in BD due to its molecular mimicry with bacterial HSP-65.

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.

New workflow for classification of genetic variants’ pathogenicity applied to hereditary recurrent fevers by the International Study Group for Systemic Autoinflammatory Diseases (INSAID)

Background Hereditary recurrent fevers (HRFs) are rare inflammatory diseases sharing similar clinical symptoms and effectively treated with anti-inflammatory biological drugs. Accurate diagnosis of HRF relies heavily on genetic testing. Objectives This study aimed to obtain an experts’ consensus on the clinical significance of gene variants in four well-known HRF genes: MEFV, TNFRSF1A, NLRP3 and MVK. Methods We configured a MOLGENIS web platform to share and analyse pathogenicity classifications of the variants and to manage a consensus-based classification process. Four experts in HRF genetics submitted independent classifications of 858 variants. Classifications were driven to consensus by recruiting four more expert opinions and by targeting discordant classifications in five iterative rounds. Results Consensus classification was reached for 804/858 variants (94%). None of the unsolved variants (6%) remained with opposite classifications (eg, pathogenic vs benign). New mutational hotspots were found in all genes. We noted a lower pathogenic variant load and a higher fraction of variants with unknown or unsolved clinical significance in the MEFV gene. Conclusion Applying a consensus-driven process on the pathogenicity assessment of experts yielded rapid classification of almost all variants of four HRF genes. The high-throughput database will profoundly assist clinicians and geneticists in the diagnosis of HRFs. The configured MOLGENIS platform and consensus evolution protocol are usable for assembly of other variant pathogenicity databases. The MOLGENIS software is available for reuse at http://github.com/molgenis/molgenis; the specific HRF configuration is available at http://molgenis.org/said/. The HRF pathogenicity classifications will be published on the INFEVERS database at https://fmf.igh.cnrs.fr/ISSAID/infevers/.

Data of indirect immunofluorescence labeling of the mouse brain sections with sera from SLE and MS patients

The data presented in this article are related to the research article entitled “Behcet Disease serum is immunoreactive to neurofilament medium which share common epitopes to bacterial HSP-65, a putative trigger” (Lule et a. 2017) [1]. The immunoreactivity to self-antigens is well characterized for systemic lupus erythematosus (SLE) and multiple sclerosis (MS) (Magro Checa et al., 2013) [2]. Indirect immunofluorescence labeling of the mouse tissue sections with patient sera has recently been popular to discover novel epitopes and gain mechanistic insight to diseases with dysregulated immunity (Lennon et al., 2004) [3]. The present article demonstrates widespread labeling of cell nuclei with SLE patient sera and sporadic filamentous labeling along the axons with MS patient sera on mouse brain sections. The filamentous immunolabeling was sometimes associated with cytoplasmic staining of cells, which sent processes along the axon bundles, suggesting that they were oligodendrocytes. Since the mouse brain tissue has little autofluorescence and limited connective tissue causing non-specific immunolabeling, it appears superior to peripheral tissues for searching serum immunoreactivity.

The analysis of inflammatory cell migration using primary neutrophils

Neutrophils are the primary defense of the host against pathogens. They remain in resting state in the circulation of the healthy individuals. When encountering cytokine or chemokine signals caused by pathogen products, neutrophils are activated and mobilized to the infected sites. The life span of neutrophils which have an essential role in terms of pathogenesis of auto-inflammatory diseases are very short. In consideration of this issue, it is restricted to study neutrophil migration in vitro. Hence, we developed a new approach on cell migration assays and neutrophil priming for long lasting research.

Comorbidities in patients with Familial Mediterranean Fever

Familial Mediterranean Fever (FMF) is the most common periodic fever syndrome, characterized by recurrent fever, serositis attacks. There are limited data on comorbidities seen in patients with FMF.

PW01-001 – Pyrin-PSTPIP1 relation during cell migration

MEFV (MEditerranien FeVer) gene mutations cause Familial Mediterranean Fever (FMF). This gene encodes a protein termed as Pyrin, which appears to play an important role in the inflammatory pathways. It is far characterized that Pyrin, which is expressed in neutrophils, interacts with PSTPIP1 and actin proteins. In previous studies PSTPIP1 has been shown to interact with cell migration proteins and actin polymerization is a main force driving neutrophil migration. Therefore, we hypothesized that Pyrin can play role in cell migration through the interaction with actin and PSTPIP1.