Dominik Filipp

The Czech Academy of Sciences | AVCR · Institute of Molecular Genetics

The single-layer epithelium of the gastrointestinal tract is a dynamically renewing tissue that ensures nutrient absorption, secretory and barrier functions and is involved in immune responses. The basis for this homeostatic renewal is the Wnt signaling pathway. Blocking this pathway can lead to epithelial damage, while its abnormal activation can...

Since its discovery, Aire has been the topic of numerous studies in its role as a transcriptional regulator in the thymus where it promotes the “promiscuous” expression of a large repertoire of tissue-restricted antigens (TRAs) that are normally expressed only in the immune periphery. This process occurs in specialized medullary thymic epithelial c...

Actin is a multi-functional protein that is involved in numerous cellular processes including cytoskeleton regulation, cell migration, and cellular integrity. In these processes, actin’s role in respect to its structure, complex mechanical, and protein-binding properties has been studied primarily in the cytoplasmic and cellular membrane compartmen...

Intestinal epithelial cells have the capacity to upregulate MHCII molecules in response to certain epithelial-adhesive microbes, such as segmented filamentous bacteria (SFB). However, the mechanism regulating MHCII expression as well as the impact of epithelial MHCII–mediated antigen presentation on T cell responses targeting those microbes remains...

The intestinal microbiota is known to influence postnatal growth. We previously found that a strain of Lactiplantibacillus plantarum (strain LpWJL) buffers the adverse effects of chronic undernutrition on the growth of juvenile germ-free mice. Here, we report that LpWJL sustains the postnatal growth of malnourished conventional animals and supports...

IL-17 protects epithelial barriers by inducing the secretion of antimicrobial peptides (AMPs). However, the effect of IL-17 on Paneth cells (PCs), the major producers of AMPs in the small intestine, is unclear. Here, we show that targeted ablation of the IL-17 receptor (IL-17R) in PCs disrupts their antimicrobial functions and decreases the frequen...

Male infertility affects approximately 14% of all European men, of which ~44% are characterized as idiopathic. There is an urgency to identify the factors that affect male fertility. One such factor, Autoimmune Regulator (AIRE), a protein found in the thymus, has been studied in the context of central tolerance functioning as a nuclear transcriptio...

Sertoli cells (SCs) are the only somatic cells that reside in seminiferous tubules of testis. They directly interact with and support the development of germ cells, thus have an indispensable role in the process of spermatogenesis. SCs first appear in a proliferative state and then, with the initiation of the first wave of spermatogenesis, progress...

The expression of MHCII by intestinal epithelial cells (IEC) determines the severity of intestinal immunopathological reactions. However, the function of MHCII on IEC under homeostatic conditions remains elusive. Here we report that MHCII expression on IECs is a hallmark of an adaptive wave of homeostatic intestinal immune responses to commensal se...

Patients with loss of function in the gene encoding the master regulator of central tolerance AIRE suffer from a devastating disorder called autoimmune polyendocrine syndrome type 1 (APS-1), characterized by a spectrum of autoimmune diseases and severe mucocutaneous candidiasis. Although the key mechanisms underlying the development of autoimmunity...

The inevitability of evolution of the adaptive immune system with its mechanism of randomly rearranging segments of the T cell receptor (TCR) gene is the generation of self-reactive clones. For the sake of prevention of autoimmunity, these clones must be eliminated from the pool of circulating T cells. This process occurs largely in the thymic medu...

The ubiquitin ligase SCFFBXO38 controls centromeric chromatin by promoting the degradation of the ZXDB protein. To determine the importance of this pathway during development, Fbxo38-deficient mice were generated. The loss of FBXO38 resulted in growth retardation affecting several organs, including the male reproductive system. A detailed analysis...

Medullary thymic epithelial cells (mTECs), which produce and present self-antigens, are essential for the establishment of central tolerance. Since mTEC numbers are limited, their function is complemented by thymic dendritic cells (DCs), which transfer mTEC-produced self-antigens via cooperative antigen transfer (CAT). While CAT is required for eff...

During ontogeny, macrophage populations emerge in the Yolk Sac (YS) via two distinct progenitor waves, prior to hematopoietic stem cell development. Macrophage progenitors from the primitive/”early EMP” and transient-definitive/”late EMP” waves both contribute to various resident primitive macrophage populations in the developing embryonic organs....

Medullary thymic epithelial cells (mTECs) which produce and present self-antigens are essential for the establishment of central tolerance. Since mTEC numbers are limited, their function is complemented by thymic dendritic cells (DCs), which transfer mTEC-produced self-antigens via cooperative antigen transfer (CAT). While CAT is required for effec...

Early embryonic hematopoiesis in mammals is defined by three successive waves of hematopoietic progenitors which exhibit a distinct hematopoietic potential and provide continuous support for the development of the embryo and adult organism. Although the functional importance of each of these waves has been analyzed, their spatio-temporal overlap an...

During ontogeny, resident macrophages (MΦs) of the nervous system emerge from haematopoietic stem cell-independent progenitors originating in the Yolk Sac (YS), so that factors impairing YS MΦ development may lead to neurodevelopmental disorders resulting from defective brain resident MΦ. Here we show that Lyl-1, a bHLH transcription factor related...

The development of thymic regulatory T cells (Treg) is mediated by Aire-regulated self-antigen presentation on medullary thymic epithelial cells (mTECs) and dendritic cells (DCs), but the cooperation between these cells is still poorly understood. Here we show that signaling through Toll-like receptors (TLR) expressed on mTECs regulates the product...

Hematopoiesis in mammalian embryos proceeds through three successive waves of hematopoietic progenitors. Since their emergence spatially and temporally overlap and phenotypic markers are often shared, the specifics regarding their origin, development, lineage restriction and mutual relationships have not been fully determined. The identification of...

The autoimmune regulator (Aire) serves an essential function for T cell tolerance by promoting the “promiscuous” expression of tissue antigens in thymic epithelial cells. Aire is also detected in rare cells in peripheral lymphoid organs, but the identity of these cells is poorly understood. Here, we report that Aire protein–expressing cells in lymp...

The gut is the biggest immune organ in the body that encloses commensal microbiota which aids in food digestion. Paneth cells, positioned at the frontline of host-microbiota interphase, can modulate the composition of microbiota. Paneth cells achieve this via the delivery of microbicidal substances, among which enteric α-defensins play the primary...

Medullary thymic epithelial cell (mTEC)-restricted expression of autoimmune regulator (Aire) is essential for establishment of immune tolerance. Recently, Aire was also shown to be expressed in cells of hematopietic and reproductive lineages. Thus, the generation of Airefl/fl mouse strain enables the investigation of the cell-specific function of A...

Type 1 diabetic (T1D) patients suffer from insulinopenia and hyperglycaemia. Studies have shown that if a patient’s hyperglycaemic environment is not compensated, it leads to complex immune dysfunctions. Similarly, T1D mothers with poor glycaemic control exert a negative impact on the immune responses of their newborns. However, questions concernin...

Supplemental Figure 1. displays the gating strategy. The gate number 1 represents CD45+ lymphocytes. From this gate, Th lymphocytes were gated as CD3+CD4+ cells (Gate #2). Gates #3, #4 and #5 represent cells carrying following marker combinations: CD4+CD25high (Gate #3), CD4+CD25high CD127low (Gate #4), CD4+CD25high FoxP3+ (Gate #5), respectively....

Adoptive T cell transfer has been shown to be an effective method used to boost tumor-specific immune responses in several types of malignancies. In this study, we set out to optimize the ACT protocol for the experimental treatment of prostate cancer. The protocol includes a pre-stimulation step whereby T cells were primed with autologous dendritic...

Time-lapse imaging of Lck and RACK1 co-redistribution into immunological synapse upon T-cell activation. Lck-deficient JCAM1.6 Jurkat T-cells co-expressing Lck-CFP (red) and RACK1-mCitrine (green) constructs were mixed with SEE pulsed RAJI B-cells (blue) and the formation of IS was observed by live cell imaging microscopy.

Time-lapse imaging RACK1 redistribution into immunological synapse upon T-cell activation. WT Jurkat T-cells expressing RACK1-EGFP (green) constructs were mixed with SEE pulsed RAJI B-cells and the formation of IS was observed by live cell imaging microscopy.

The initiation of T-cell signaling is critically dependent on the function of the member of Src family tyrosine kinases, Lck. Upon T-cell antigen receptor (TCR) triggering, Lck kinase activity induces the nucleation of signal-transducing hubs that regulate the formation of complex signaling network and cytoskeletal rearrangement. In addition, the d...

Background & aims: Autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED) is an autoimmune disorder characterized by chronic mucocutaneous candidiasis, hypoparathyroidism, and adrenal insufficiency, but patients also develop intestinal disorders. APECED is an autosomal recessive disorder caused by mutations in the autoimmune regul...

The initiation of T-cell receptor (TCR) signaling, based on the cobinding of TCR and CD4-Lck heterodimer to a peptide-major histocompatibility complex II on antigen presenting cells, represents a classical model of T-cell signaling. What is less clear however, is the mechanism which translates TCR engagement to the phosphorylation of immunoreceptor...

Mammalian Toll-like receptors (TLRs) in adult animals serve indispensible functions in establishing innate and adaptive immunity and contributing to the homeostasis of surrounding tissues. However, the expression and function of TLRs during mammalian embryonic development has not been studied so far. Here, we show that CD45(+) CD11b(+) F4/80(+) mac...

The preparation of galactofuranosyl-containing disaccharidic parts of natural glycoconjugates was per-formed according to a chemo-enzymatic synthesis. Our goals were firstly to develop an alternative approach to standard chemical strategies by limiting the number of reaction and purification steps, and secondly to evaluate the scope of the Araf51 b...

The preparation of galactofuranosyl-containing disaccharidic parts of natural glycoconjugates was performed according to a chemo-enzymatic synthesis. Our goals were firstly to develop an alternative approach to standard chemical strategies by limiting the number of reaction and purification steps, and secondly to evaluate the scope of the Araf51 bi...

Francisella tularensis is a highly infectious intracellular pathogen that has evolved an efficient strategy to subvert host defense response to survive inside the host. The molecular mechanisms regulating these host-pathogen interactions and especially those that are initiated at the time of the bacterial entry via its attachment to the host plasma...

Detailed description of autoantibodies status of study cohort could be found in Table 1s. Greatest changes in a gene expression of 20 up- or downregulated genes among our groups are listed in a Table 2s.

Type 1 Diabetes (T1D) is considered to be a T-helper- (Th-) 1 autoimmune disease; however, T1D pathogenesis likely involves many factors, and sufficient tools for autoreactive T cell detection for the study of this disease are currently lacking. In this study, using gene expression microarrays, we analysed the effect of diabetes-associated autoanti...

The increasing incidence of various autoimmune diseases represents a serious medical, economical and social burden on society. They affect approximately 7% of the population and are often associated with the deterioration of a patient's quality of life and shortening of lifetime expectancy. Type 1 diabetes (DM1) is an autoimmune diseasewhereby self...

Type 1 diabetes (T1D) is an autoimmune disease caused by T-cell mediated destruction of pancreatic beta cells. Recently, small cationic α-defensin molecules have been implicated in the pathogenesis of certain inflammatory and autoimmune diseases. The purpose of this study was to assess the α-defensin expression in patients with T1D and elucidate th...

In spite of a comprehensive understanding of the schematics of T cell receptor (TCR) signaling, the mechanisms regulating compartmentalization of signaling molecules, their transient interactions, and rearrangement of membrane structures initiated upon TCR engagement remain an outstanding problem. These gaps in our knowledge are exemplified by rece...

Lck is the principal signal-generating tyrosine kinase of the T cell activation mechanism. We have previously demonstrated that induced Lck activation outside of lipid rafts (LR) results in the rapid translocation of a fraction of Lck to LR. While this translocation predicates the subsequent production of IL-2, the mechanism underpinning this proce...

Type 1 diabetes (T1D) is an autoimmune disease characterized by the lack of insulin due to an autoimmune destruction of pancreatic beta cells. Here, we report a unique case of a family with naturally conceived quadruplets in which T1D was diagnosed in two quadruplets simultaneously. At the same time, the third quadruplet was diagnosed with the pre-...

Introduction:  Expression features of genetic landscape which predispose an individual to the type 1 diabetes are poorly understood. We addressed this question by comparing gene expression profile of freshly isolated peripheral blood mononuclear cells isolated from either patients with type 1 diabetes, or their first degree relatives or healthy con...

D-Galactofuranosyl-containing conjugates are ubiquitous in many pathogenic microorganisms, but completely absent from mammals. As they may constitute interesting pharmacophores, recent works have been dedicated to their preparation. Besides well-reported chemical procedures, enzymatic approaches are still limited, mainly due to the lack of the corr...

Mechanisms regulating the activation and delivery of function of Lck and Fyn are central to the generation of the most proximal signaling events emanating from the T cell antigen receptor (TcR) complex. Recent results demonstrate that lipid rafts (LR) segregate Lck and Fyn and play a fundamental role in the temporal and spatial coordination of thei...

The Wiskott–Aldrich syndrome protein (WASp) plays a major role in coupling T cell antigen receptor (TCR) stimulation to induction of actin cytoskeletal changes required for T cell activation. Here, we report that WASp inducibly binds the sorting nexin 9 (SNX9) in T cells and that WASp, SNX9, p85, and CD28 colocalize within clathrin-containing endoc...

The NK cell receptor protein 1 (NKR-P1) (CD161) molecules represent a family of type II transmembrane C-type lectin-like receptors expressed predominantly by NK cells. Despite sharing a common NK1.1 epitope, the mouse NKR-P1B and NKR-P1C receptors possess opposing functions in NK cell signaling. Engagement of NKR-P1C stimulates cytotoxicity of targ...

While both lck and fyn are essential to generating the full sequelae of proximal signals emanating from the TcR/CD3 complex, thus far, modeling the temporal and spatial involvement of fyn has been problematic. The absence of a binding partner, analogous to the role of CD4 in targeting lck, commonalties of structure, common modes of activation and o...

Severe impairment of exocrine pancreatic secretion has recently been demonstrated in a clinical study in sepsis and septic shock patients. The purpose of this study was to further evaluate involvement of the pancreas in the acute phase reaction in sepsis. Using a normotensive rat model of Pseudomonas pneumonia-induced sepsis, we assessed the expres...

Recent results provide insight into the temporal and spatial relationship governing lck-dependent fyn activation and demonstrate TCR/CD4-induced activation and translocation of lck into lipid rafts and the ensuing activation of colocalized fyn. The prediction follows that directly targeting lck to lipid rafts will bypass the requirement for juxtapo...

Whether or how the activation of Lck and Fyn during T cell receptor (TCR) signaling is coordinated, and their delivery of function integrated, is unknown. Here we show that lipid rafts function to segregate Lck and Fyn in T cells before activation. Coaggregation of TCR and CD4 leads to Lck activation within seconds outside lipid rafts, followed by...

Induction of resting B cell growth and differentiation requires a complex series of temporally coordinated signals that are initiated on contact with activated helper T cells. These signals complement one another, each rendering the B cell susceptible to factors supporting progressive activation. Here, we demonstrate that soluble CD14 (sCD14) bypas...

The expression of genes for synthesis of auxin (iaaM and iaaH) and cytokinins (ipt) was studied in tobacco plants transformed by two Agrobacterium tumefaciens strains C 58 and LBA 4404. The strain LBA 4404 carried binary vector plasmid pCB 1334 (ipt gene) and plasmid pCB 1349 (iaaM, iaaH and ila genes). Both plasmids carried reportered gene for npt...

The 30-kb cluster comprising close to 20 copies of tandemly repeated Stellate genes was localized in the distal heterochromatin of the X chromosome. Of 10 sequenced genes, nine contain undamaged open reading frames with extensive similarity to protein kinase CK2 beta-subunit; one gene is interrupted by an insertion. The heterochromatic array of Ste...

This study describes the karyotype of strain 270 of the yeast-like fungus Endomyces magnusii. It consists of 13 chromosomal DNA molecules, the size of which range between 1.2 and 5.7Mb producing a genome size of approximately 38Mb. By comparing the karyotype of six strains of E. magnusii, we revealed two main chromosome length polymorphisms (CLPs)...