The pertussis agent Bordetella pertussis produces a number of virulence factors, of which the filamentous hemagglutinin (FhaB) plays a role in B. pertussis adhesion to epithelial and phagocytic cells. Moreover, FhaB was recently found to play a crucial role in nasal cavity infection and B. pertussis transmission to new hosts. The 367 kDa FhaB protein translocates through an FhaC pore to the outer bacterial surface and is eventually processed to a ~220 kDa N-terminal FHA fragment by the SphB1 protease. A fraction of the mature FHA then remains associated with bacterial cell surface, while most of FHA is shed into the bacterial environment. Previously reported indirect evidence suggested that FHA, or its precursor FhaB, may bind the β2 integrin CD11b/CD18 of human macrophages. Therefore, we assessed FHA binding to various cells producing or lacking the integrin and show that purified mature FHA does not bind CD11b/CD18. Further results then revealed that the adhesion of B. pertussis to cells does not involve an interaction between the bacterial surface-associated FhaB and/or mature FHA and the β2 integrin CD11b/CD18. In contrast, FHA binding was strongly inhibited at micromolar concentrations of heparin, corroborating that the cell binding of FHA is ruled by the interaction of its heparin-binding domain with sulfated glycosaminoglycans on the cell surface.

• MeSH
• antigeny CD18 MeSH
• bakteriální adheze MeSH
• bakteriální adheziny metabolismus   MeSH
• Bordetella pertussis * metabolismus   MeSH
• faktory virulence rodu Bordetella MeSH
• glykosaminoglykany MeSH
• hemaglutininy metabolismus   MeSH
• heparin MeSH
• integriny MeSH
• lidé MeSH
• makrofágový antigen 1 MeSH
• pertuse * MeSH
• proteasy MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• elektronová mikroskopie MeSH
• integriny fyziologie   MeSH
• modely u zvířat MeSH
• molekuly buněčné adheze MeSH
• nukleární magnetická rezonance biomolekulární MeSH
• rezonanční přenos fluorescenční energie MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• recenze MeSH

The mechanisms leading to autoimmune and inflammatory diseases in the CNS have not been elucidated. The environmental triggers of the aberrant presence of CD4+ T cells in the CNS are not known. In this article, we report that abnormal β-catenin expression in T cells drives a fatal neuroinflammatory disease in mice that is characterized by CNS infiltration of T cells, glial activation, and progressive loss of motor function. We show that enhanced β-catenin expression in T cells leads to aberrant and Th1-biased T cell activation, enhanced expression of integrin α4β1, and infiltration of activated T cells into the spinal cord, without affecting regulatory T cell function. Importantly, expression of β-catenin in mature naive T cells was sufficient to drive integrin α4β1 expression and CNS migration, whereas pharmacologic inhibition of integrin α4β1 reduced the abnormal T cell presence in the CNS of β-catenin-expressing mice. Together, these results implicate deregulation of the Wnt/β-catenin pathway in CNS inflammation and suggest novel therapeutic strategies for neuroinflammatory disorders.

• MeSH
• beta-katenin genetika   imunologie   MeSH
• integrin alfa4beta1 genetika   imunologie   MeSH
• mícha imunologie   patologie   MeSH
• myši knockoutované MeSH
• myši MeSH
• nemoci míchy genetika   imunologie   patologie   MeSH
• signální dráha Wnt genetika   imunologie   MeSH
• Th1 buňky imunologie   patologie   MeSH
• zánět genetika   imunologie   patologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Various strategies have been employed to improve the reliability of 2D, 3D, and co-culture in vitro models of nonalcoholic fatty liver disease, including using extracellular matrix proteins such as collagen I to promote cell adhesion. While studies have demonstrated the significant benefits of culturing cells on collagen I, its effects on the HepG2 cell line after exposure to palmitate (PA) have not been investigated. Therefore, this study aimed to assess the effects of PA-induced lipotoxicity in HepG2 cultured in the absence or presence of collagen I. HepG2 cultured in the absence or presence of collagen I was exposed to PA, followed by analyses that assessed cell proliferation, viability, adhesion, cell death, mitochondrial respiration, reactive oxygen species production, gene and protein expression, and triacylglycerol accumulation. Culturing HepG2 on collagen I was associated with increased cell proliferation, adhesion, and expression of integrin receptors, and improved cellular spreading compared to culturing them in the absence of collagen I. However, PA-induced lipotoxicity was greater in collagen I-cultured HepG2 than in those cultured in the absence of collagen I and was associated with increased α2β1 receptors. In summary, the present study demonstrated for the first time that collagen I-cultured HepG2 exhibited exacerbated cell death following exposure to PA through integrin-mediated death. The findings from this study may serve as a caution to those using 2D models or 3D scaffold-based models of HepG2 in the presence of collagen I.

• MeSH
• buněčná adheze * účinky léků   MeSH
• buněčná smrt účinky léků   MeSH
• buňky Hep G2 MeSH
• integrin alfa2beta1 metabolismus   MeSH
• integriny metabolismus   genetika   MeSH
• kolagen typu I * metabolismus   genetika   MeSH
• lidé MeSH
• nealkoholová steatóza jater metabolismus   patologie   MeSH
• palmitany toxicita   farmakologie   MeSH
• proliferace buněk * účinky léků   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• viabilita buněk * účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Folate, also known as vitamin B9, is necessary for essential cellular functions such as DNA synthesis, repair, and methylation. It is supplied to the cell via several transporters and receptors, including folate receptor (FR) β, a GPI-anchored protein belonging to the folate receptor family. As FRβ shows a restricted expression to cells of myeloid origin and only a subset of activated macrophages and placental cells have been shown to express functional FRβ, it represents a promising target for future therapeutic strategies. In this study, we performed affinity purification and mass spectrometric analysis of the protein microenvironment of FRβ in the plasma membrane of human FRβ(+) macrophages and FRβ-transduced monocytic THP-1 cells. In this manner, we identified a novel role of FRβ: that is, we report functional interactions of FRβ with receptors mediating cellular adhesion, in particular the CD11b/CD18 β2 integrin heterodimer complement receptor type 3/Mac-1. This interaction results in impeded adhesion of FRβ(+) human primary macrophages and THP-1 cells to collagen in comparison with their FRβ(-) counterparts. We further show that FRβ is only expressed by human macrophages when differentiated with M-CSF. These findings thus identify FRβ as a novel CD11b/CD18 regulator for trafficking and homing of a subset of macrophages on collagen.

• MeSH
• antigeny CD11b fyziologie   MeSH
• antigeny CD18 fyziologie   MeSH
• buněčná adheze MeSH
• folátový receptor 2 fyziologie   MeSH
• kolagen farmakologie   MeSH
• kultivované buňky MeSH
• kyselina listová metabolismus   MeSH
• lidé MeSH
• makrofágy fyziologie   MeSH
• pohyb buněk MeSH
• proliferace buněk MeSH
• tetradekanoylforbolacetát farmakologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Integrins are transmembrane cell receptors involved in two crucial mechanisms for successful fertilization, namely, mammalian intracellular signaling and cell adhesion. Integrins α6β4, α3β1 and α6β1 are three major laminin receptors expressed on the surface of mammalian cells including gametes, and the presence of individual integrin subunits α3, α6, β1 and β4 has been previously detected in mammalian sperm. However, to date, proof of the existence of individual heterodimer pairs in sperm and their detailed localization is missing. The major conclusion of this study is evidence that the β4 integrin subunit is expressed in mouse sperm and that it pairs with subunit α6; additionally, there is a detailed identification of integrin heterodimer pairs across individual membranes in an intact mouse sperm head. We also demonstrate the existence of β4 integrin mRNAs in round spermatids and spermatogonia by q-RT-PCR, which was further supported by sequencing the PCR products. Using super-resolution microscopy accompanied by colocalization analysis, we located integrin subunits as follows: α6/β4-inner apical acrosomal membrane and equatorial segment; α3, α6/β1, β4-plasma membrane overlaying the apical acrosome; and α3/β1-outer acrosomal membrane. The existence of α6β4, α3β1 and α6β1 heterodimers was further confirmed by proximity ligation assay (PLA). In conclusion, we delivered detailed characterization of α3, α6, β1 and β4 integrin subunits, showing their presence in distinct compartments of the intact mouse sperm head. Moreover, we identified sperm-specific localization for heterodimers α6β4, α3β1 and α6β1, and their membrane compartmentalization and the presented data show a complexity of membranes overlaying specialized microdomain structures in the sperm head. Their different protein compositions of these individual membrane rafts may play a specialized role, based on their involvement in sperm-epithelium and sperm-egg interaction.

• MeSH
• biologické modely MeSH
• integriny chemie   metabolismus   MeSH
• kompartmentace buňky * MeSH
• multimerizace proteinu * MeSH
• myši inbrední C57BL MeSH
• podjednotky proteinů metabolismus   MeSH
• proteinové domény MeSH
• spermie metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• adenylátcyklasový toxin MeSH
• antigeny CD11b imunologie   MeSH
• antigeny CD18 imunologie   MeSH
• Bordetella pertussis patogenita   MeSH
• faktory virulence rodu Bordetella MeSH
• integriny imunologie   MeSH
• pertusový toxin MeSH

Fertilization is a complex process that requires successive stages and culminates in the adhesion/fusion of gamete membranes. If the question of the involvement of oocyte integrins has been swept away by deletion experiments, that of the involvement of sperm integrins remains to be further characterized. In the present study, we addressed the question of the feasibility of sperm-oocyte adhesion/fusion and early implantation in the absence of sperm β1 integrin. Males and females with β1 integrin-depleted sperm and oocytes were mated, and fertilization outcome was monitored by a gestational ultrasound analysis. Results suggest that although the sperm β1 integrin participates in gamete adhesion/fusion, it is dispensable for fertilization in mice. However, sperm- and/or oocyte-originated integrin β1 is essential for post-implantation development. Redundancy phenomena could be at the origin of a compensatory expression or alternative dimerization pattern.

• MeSH
• antigeny CD29 * genetika   metabolismus   MeSH
• fertilizace MeSH
• integriny metabolismus   MeSH
• interakce spermie a vajíčka * MeSH
• myši MeSH
• oocyty metabolismus   MeSH
• sperma metabolismus   MeSH
• spermie metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Bordetella pertussis adenylate cyclase (AC) toxin-hemolysin (Hly) (CyaA, ACT, or AC-Hly) is a cytotoxin of the RTX (repeat in toxin) family. It delivers into target cells an AC domain that catalyzes uncontrolled conversion of ATP to cAMP, a key signaling molecule subverting phagocyte functions. CyaA utilizes a heavily N-glycosylated beta(2) integrin receptor CD11b/CD18 (alpha(M)beta(2), Mac-1, or CR3). We show that deglycosylation of cell surface proteins by glycosidase treatment, or inhibition of protein N-glycosylation by tunicamycin, ablates CyaA binding and penetration of CD11b-expressing cells. Furthermore, binding of CyaA to cells was strongly inhibited in the presence of free saccharides occurring as building units of integrin oligosaccharide complex, whereas saccharides absent from integrin oligosaccharide chains failed to inhibit CyaA binding to CD11b/CD18-expressing cells. CyaA, hence, selectively recognized sugar residues of N-linked oligosaccharides of integrins. Moreover, glycosylation of CD11a/CD18, another receptor of the beta(2) integrin family, was also essential for cytotoxic action of other RTX cytotoxins, the leukotoxin of Aggregatibacter actinomycetemcomitans (LtxA) and the Escherichia coli alpha-Hly (HlyA). These results show that binding and killing of target cells by CyaA, LtxA, and HlyA depends on recognition of N-linked oligosaccharide chains of beta(2) integrin receptors. This sets a new paradigm for action of RTX cytotoxins.

• MeSH
• adenylátcyklasový toxin metabolismus   MeSH
• antigeny CD11b metabolismus   MeSH
• antigeny CD18 metabolismus   MeSH
• bakteriální proteiny MeSH
• bakteriální toxiny metabolismus   MeSH
• Bordetella enzymologie   chemie   patogenita   MeSH
• financování organizované MeSH
• glykosylace MeSH
• hemolyziny MeSH
• lidé MeSH
• oligosacharidy metabolismus   MeSH
• vazebná místa MeSH
• Check Tag
• lidé MeSH

According to previous studies, integrins play an important role in the mechanotransduction. The aim of this study was to examine the role of integrin subunits and its down-stream signaling molecules in the cyclic hydrodynamic pressure-induced proliferation of human bladder smooth muscle cells (HBSMCs) cultured in scaffolds. The HBSMCs cultured in scaffolds were subjected to four different levels of cyclic hydrodynamic pressure for 24 hours, which were controlled by a BOSE BioDynamic bioreactor. Flow cytometry was used to examine cell cycle distribution. Real-time RT-PCR and western blotting were used to examine the expression levels of integrin subunits and their downstream signaling molecules. Integrin alpha5 siRNA was applied to validate the role of integrin alpha5 in cell proliferation. Here, we showed that cyclic hydrodynamic pressure promoted proliferation of HBSMCs. The cyclic hydrodynamic pressure also increased expression of integrin alpha5 and phosphorylation of FAK, the key mediator of integrin alpha5 signaling, but not that of integrin alpha1, alpha3, alpha4, alphav, beta1 and beta3. Moreover, inhibition of integrin alpha5 decreased the level of p-FAK and abolished proliferation of HBSMCs stimulated by cyclic hydrodynamic pressure. Taken together, we demonstrate for the ?rst time that the integrin alpha5-FAK signaling pathway controls the proliferation of HBSMCs in response to cyclic hydrodynamic pressure.

• MeSH
• buněčný převod mechanických signálů fyziologie   MeSH
• fokální adhezní kinasa 1 biosyntéza   MeSH
• hydrodynamika * MeSH
• integrin alfa5 biosyntéza   MeSH
• kultivované buňky MeSH
• lidé MeSH
• močový měchýř cytologie   metabolismus   MeSH
• myocyty hladké svaloviny metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH