Impact of local human microbiota on the allergic diseases: Organ-organ interaction.

The homogeneous impact of local dysbiosis on the development of allergic diseases in the same organ has been thoroughly studied. However, much less is known about the heterogeneous influence of dysbiosis within one organ on allergic diseases in other organs. A comprehensive analysis of the current scientific literature revealed that most of the relevant publications focus on only three organs: gut, airways, and skin. Moreover, the interactions appear to be mainly unidirectional, that is, dysbiotic conditions of the gut being associated with allergic diseases of the airways and the skin. Similar to homogeneous interactions, early life appears to be not only a crucial period for the formation of the microbiota in one organ but also for the later development of allergic diseases in other organs. In particular, we were able to identify a number of specific bacterial and fungal species/genera in the intestine that were repeatedly associated in the literature with either increased or decreased allergic diseases of the skin, like atopic dermatitis, or the airways, like allergic rhinitis and asthma. The reported studies indicate that in addition to the composition of the microbiome, also the relative abundance of certain microbial species and the overall diversity are associated with allergic diseases of the corresponding organs. As anticipated for human association studies, the underlying mechanisms of the organ-organ crosstalk could not be clearly resolved yet. Thus, further work, in particular experimental animal studies are required to elucidate the mechanisms linking dysbiotic conditions of one organ to allergic diseases in other organs.

Autoantibodies are highly prevalent in non-SARS-CoV-2 respiratory infections and critical illness.

The widespread presence of autoantibodies in acute infection with SARS-CoV-2 is increasingly recognized, but the prevalence of autoantibodies in non-SARS-CoV-2 infections and critical illness has not yet been reported. We profiled IgG autoantibodies in 267 patients from 5 independent cohorts with non-SARS-CoV-2 viral, bacterial, and noninfectious critical illness. Serum samples were screened using Luminex arrays that included 58 cytokines and 55 autoantigens, many of which are associated with connective tissue diseases (CTDs). Samples positive for anti-cytokine antibodies were tested for receptor blocking activity using cell-based functional assays. Anti-cytokine antibodies were identified in > 50% of patients across all 5 acutely ill cohorts. In critically ill patients, anti-cytokine antibodies were far more common in infected versus uninfected patients. In cell-based functional assays, 11 of 39 samples positive for select anti-cytokine antibodies displayed receptor blocking activity against surface receptors for Type I IFN, GM-CSF, and IL-6. Autoantibodies against CTD-associated autoantigens were also commonly observed, including newly detected antibodies that emerged in longitudinal samples. These findings demonstrate that anti-cytokine and autoantibodies are common across different viral and nonviral infections and range in severity of illness.

Influence of a Heterologous (ChAdOx1-nCoV-19/BNT162b2) or Homologous (BNT162b2/BNT162b2) Vaccination Regimen on the Antibody and T Cell Response to a Third Vaccination with BNT162b2.

Emerging numbers of SARS-CoV-2 infections are currently combated with a third vaccination. Considering the different vaccination regimens used for the first two vaccine doses, we addressed whether the previous vaccination influences the immune response to the booster. Participants for this prospective study were recruited from among healthcare workers. N = 20 participants were previously vaccinated with two doses of BNT162b2, and n = 53 received a priming dose of ChAdOx1-nCoV-19 followed by a BNT162b2 dose. Participants were vaccinated with a third dose of BNT162b2 in December 2021. Antibody concentrations were determined after vaccination, and in a subset of n = 19 participants, T cell responses were evaluated. Anti-S concentrations and IFNγ production increased during the first 21 days. The choice of the first and second vaccineshad no influence on the final outcome of the booster vaccination. Before booster vaccination, antibody concentrations were lower for older participants but increased more strongly over time.

Autoantibodies targeting cytokines and connective tissue disease autoantigens are common in acute non-SARS-CoV-2 infections.

The widespread presence of autoantibodies in acute infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is increasingly recognized, but the prevalence of autoantibodies in infections with organisms other than SARS-CoV-2 has not yet been reported. We used protein arrays to profile IgG autoantibodies from 317 samples from 268 patients across a spectrum of non-SARS-CoV-2 infections, many of whom were critically ill with pneumonia. Anti-cytokine antibodies (ACA) were identified in > 50% of patients infected with non-SARS-CoV-2 viruses and other pathogens, including patients with pneumonia attributed to bacterial causes. In cell-based functional assays, some ACA blocked binding to surface receptors for type I interferons (Type I IFN), granulocyte-macrophage colony-stimulating factor (GM-CSF), and interleukin-6 (IL-6). Autoantibodies against traditional autoantigens associated with connective tissue diseases (CTDs) were also commonly observed in these cohorts, including newly-detected antibodies that emerged in longitudinal samples from patients infected with influenza. We conclude that autoantibodies, some of which are functionally active, may be much more prevalent than previously appreciated in patients who are symptomatically infected with diverse pathogens.

New-onset IgG autoantibodies in hospitalized patients with COVID-19.

COVID-19 is associated with a wide range of clinical manifestations, including autoimmune features and autoantibody production. Here we develop three protein arrays to measure IgG autoantibodies associated with connective tissue diseases, anti-cytokine antibodies, and anti-viral antibody responses in serum from 147 hospitalized COVID-19 patients. Autoantibodies are identified in approximately 50% of patients but in less than 15% of healthy controls. When present, autoantibodies largely target autoantigens associated with rare disorders such as myositis, systemic sclerosis and overlap syndromes. A subset of autoantibodies targeting traditional autoantigens or cytokines develop de novo following SARS-CoV-2 infection. Autoantibodies track with longitudinal development of IgG antibodies recognizing SARS-CoV-2 structural proteins and a subset of non-structural proteins, but not proteins from influenza, seasonal coronaviruses or other pathogenic viruses. We conclude that SARS-CoV-2 causes development of new-onset IgG autoantibodies in a significant proportion of hospitalized COVID-19 patients and are positively correlated with immune responses to SARS-CoV-2 proteins.

New-Onset IgG Autoantibodies in Hospitalized Patients with COVID-19.

Coronavirus Disease 2019 (COVID-19), caused by Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), is associated with a wide range of clinical manifestations, including autoimmune features and autoantibody production. We developed three different protein arrays to measure hallmark IgG autoantibodies associated with Connective Tissue Diseases (CTDs), Anti-Cytokine Antibodies (ACA), and anti-viral antibody responses in 147 hospitalized COVID-19 patients in three different centers. Autoantibodies were identified in approximately 50% of patients, but in <15% of healthy controls. When present, autoantibodies largely targeted autoantigens associated with rare disorders such as myositis, systemic sclerosis and CTD overlap syndromes. Anti-nuclear antibodies (ANA) were observed in ∼25% of patients. Patients with autoantibodies tended to demonstrate one or a few specificities whereas ACA were even more prevalent, and patients often had antibodies to multiple cytokines. Rare patients were identified with IgG antibodies against angiotensin converting enzyme-2 (ACE-2). A subset of autoantibodies and ACA developed de novo following SARS-CoV-2 infection while others were transient. Autoantibodies tracked with longitudinal development of IgG antibodies that recognized SARS-CoV-2 structural proteins such as S1, S2, M, N and a subset of non-structural proteins, but not proteins from influenza, seasonal coronaviruses or other pathogenic viruses. COVID-19 patients with one or more autoantibodies tended to have higher levels of antibodies against SARS-CoV-2 Nonstructural Protein 1 (NSP1) and Methyltransferase (ME). We conclude that SARS-CoV-2 causes development of new-onset IgG autoantibodies in a significant proportion of hospitalized COVID-19 patients and are positively correlated with immune responses to SARS-CoV-2 proteins.

Apolipoprotein E allele frequencies in chronic and self-limited hepatitis C suggest a protective effect of APOE4 in the course of hepatitis C virus infection.

BACKGROUND & AIMS: Infectious hepatitis C virus (HCV) particles bind to host lipoproteins such as low-density lipoproteins (LDLs). Low-density lipoprotein receptors (LDLR) have been termed candidate receptors for HCV-LDL complexes. Functional host genetic single nucleotide polymorphisms (SNPs) in the apolipoprotein E (APOE) gene encoding apolipoprotein E (apoE) - a major structural LDL component and natural ligand of LDLR - likely influence the course of HCV infection. We investigated the prevalence of APOE SNPs in two large and independent cohorts of patients with chronic HCV infection compared to respective controls. METHODS: We genotyped 996 chronically HCV-infected patients; 179 patients with spontaneous HCV clearance; 283 individuals with non-HCV-associated liver disease; and 2 234 healthy controls. RESULTS: APOE genotype proportions in patients with persistent HCV infection significantly differed from healthy controls (P = 0.007) primarily because of a substantial under-representation of APOE4 alleles in chronically HCV-infected patients (10.2%) compared to 13.0% in healthy controls (P = 0.001). The distribution of APOE4 allele positive genotypes (ε2ε4, ε3ε4, ε4ε4) also significantly differed between chronically HCV-infected patients and healthy controls (1.4%, 17%, 1% vs. 2.4%, 20.5%, 1.7%; P = 0.001), suggesting a protective effect of the APOE4 allele in HCV infection. This was confirmed by a significant over-representation of the APOE4 allele in patients with spontaneous HCV clearance (17.6%; P = 0.00008). The APOE4 allele distribution in patients with non-HCV-associated liver disease (14.0%) was very similar to healthy controls and also differed from chronically HCV-infected patients (P = 0.012), suggesting HCV specificity. CONCLUSIONS: Our findings suggest that the APOE4 allele may confer a protective effect in the course of HCV infection.

LI-cadherin cis-dimerizes in the plasma membrane Ca(2+) independently and forms highly dynamic trans-contacts.

LI-cadherin belongs to the family of 7D-cadherins that is characterized by a low sequence similarity to classical cadherins, seven extracellular cadherin repeats (ECs), and a short cytoplasmic domain. Nevertheless, LI-cadherins mediates Ca(2+)-dependent cell-cell adhesion and induces an epitheloid cellular phenotype in non-polarized CHO cells. Whereas several studies suggest that classical cadherins cis-dimerize in a Ca(2+)-dependent manner and interact in trans by strand-swapping tryptophan 2 of EC1, little is known about the molecular interactions of LI-cadherin, which lacks tryptophan 2. We thus expressed fluorescent LI-cadherin fusion proteins in HEK293 and CHO cells, analyzed their cell-cell adhesive properties and studied their cellular distribution, cis-interaction, and lateral diffusion in the presence and absence of Ca(2+). LI-cadherin highly concentrates in cell contact areas but rapidly leaves those sites upon Ca(2+) depletion and redistributes evenly on the cell surface, indicating that it is only kept in the contact areas by trans-interactions. Fluorescence resonance energy transfer analysis of LI-cadherin-CFP and -YFP revealed that LI-cadherin forms cis-dimers that resist Ca(2+) depletion. As determined by fluorescence redistribution after photobleaching, LI-cadherin freely diffuses in the plasma membrane as a cis-dimer (D = 0.42 ± 0.03 µm(2)/s). When trapped by trans-binding in cell contact areas, its diffusion coefficient decreases only threefold to D = 0.12 ± 0.01 µm(2)/s, revealing that, in contrast to classical and desmosomal cadherins, trans-contacts formed by LI-cadherin are highly dynamic.

Features of "All LNA" Duplexes Showing a New Type of Nucleic Acid Geometry.

"Locked nucleic acids" (LNAs) belong to the backbone-modified nucleic acid family. The 2'-O,4'-C-methylene-ß-D-ribofuranose nucleotides are used for single or multiple substitutions in RNA molecules and thereby introduce enhanced bio- and thermostability. This renders LNAs powerful tools for diagnostic and therapeutic applications. RNA molecules maintain the overall canonical A-type conformation upon substitution of single or multiple residues/nucleotides by LNA monomers. The structures of "all" LNA homoduplexes, however, exhibit significant differences in their overall geometry, in particular a decreased twist, roll and propeller twist. This results in a widening of the major groove, a decrease in helical winding, and an enlarged helical pitch. Therefore, the LNA duplex structure can no longer be described as a canonical A-type RNA geometry but can rather be brought into proximity to other backbone-modified nucleic acids, like glycol nucleic acids or peptide nucleic acids. LNA-modified nucleic acids provide thus structural and functional features that may be successfully exploited for future application in biotechnology and drug discovery.

Properties of an LNA-modified ricin RNA aptamer.

'Locked nucleic acids' (LNAs) are sugar modified nucleic acids containing the 2'-O-4'C-methylene-ß-D-ribofuranoses. The substitution of RNAs with LNAs leads to an enhanced thermostability. Aptamers are nucleic acids, which are selected for specific target binding from a large library pool by the 'SELEX' method. Introduction of modified nucleic acids into aptamers can improve their stability. The stem region of a ricin A chain RNA aptamer was substituted by locked nucleic acids. Different constructs of the LNA-substituted aptamers were examined for their thermostability, binding activity, folding and RNase sensitivity as compared to the natural RNA counterpart. The LNA-modified aptamers were active in target binding, while the loop regions and the adjacent stem nucleotides remained unsubstituted. The thermostability and RNase resistance of LNA substituted aptamers were enhanced as compared to the native RNA aptamer. This study supports the approach to substitute the aptamer stem region by LNAs and to leave the loop region unmodified, which is responsible for ligand binding. Thus, LNAs possess an encouraging potential for the development of new stabilized nucleic acids and will promote future diagnostic and therapeutic applications.

Impact of microvessel density on lymph node metastasis and survival after curative resection of pancreatic cancer.

PURPOSE: The roles of angiogenesis and the most prominent angiogenic vascular endothelial growth factor (VEGF) in diseases of the pancreas remain controversial. We compared microvessel density (MVD) and VEGF status in normal pancreatic, chronic pancreatic, and pancreatic cancer (PC) tissues to establish their prognostic relevance. METHODS: Eighty samples of PC tissue, 32 samples of normal pancreatic tissue, and 20 samples of chronic pancreatitis (cP) tissue were immunostained with monoclonal anti-CD31 and polyclonal anti-VEGF antibody. The MVD was correlated with clinicopathological features and survival. RESULTS: Microvessel density was higher in PC than in cP (P < 0.001). Residual tumor status was highly predictive for survival (P < 0.001). After stratification for residual tumor status, we identified lymph node metastasis (LNM) in more than two lymph nodes (P < 0.04) and high MVD (P < 0.03) as risk factors for mortality. Multivariate analysis revealed only a high MVD (P = 0.03, odds ratio 0.441, 95% confidence interval 0.211-0.821) as an independent predictor of poor survival. Vascular endothelial growth factor was found over stromal cells in cP and over ductal adenocarcinoma cells in PC. Vascular endothelial growth factor expression status was not predictive of survival (P < 0.07). CONCLUSION: This study confirms the role of angiogenesis in PC and identifies MVD as an independent prognostic factor in patients with curatively resected PC.

Enhanced ovalbumin-induced airway inflammation in CD26-/- mice.

In this study, we investigated the potential role of CD26 in ovalbumin (OVA)-induced airway inflammation using CD26 gene knockout mice. Compared with WT counterparts, CD26(-/-) mice showed an obviously enhanced tissue response and denser pulmonary infiltrates containing eosinophils around vessels and in the parenchyma after OVA sensitization and challenge. Serum IgG, including subclasses IgG1 and IgG2a, was greatly reduced in CD26(-/-) mice, but serum IgE remained unchanged. CD26(-/-) mice had increased mRNA expression of the Th2 cytokines IL-4, IL-5, and IL-13 in the lungs compared with WT mice, whereas the levels of the pro-Th1 cytokine IL-12p40 were similar in both strains. Consequently, enhanced protein secretion of IL-4, IL-5, and IL-13 was detected in bronchoalveolar lavage (BAL) fluid from CD26(-/-) mice. In agreement with overexpressed Th2 cytokines, both mRNA transcript and protein levels of chemokines eotaxin and RANTES, as well as their receptors CC chemokine receptor 3 (CCR3) and CCR5, were elevated in CD26(-/-) mice. These results suggest a protective role for CD26 in restricting OVA-induced airway inflammation.

The Seryl-tRNA synthetase/tRNASer acceptor stem interface is mediated via a specific network of water molecules.

tRNAs are aminoacylated by the aminoacyl-tRNA synthetases. There are at least 20 natural amino acids, but due to the redundancy of the genetic code, 64 codons on the mRNA. Therefore, there exist tRNA isoacceptors that are aminoacylated with the same amino acid, but differ in their sequence and in the anticodon. tRNA identity elements, which are sequence or structure motifs, assure the amino acid specificity. The Seryl-tRNA synthetase is an enzyme that depends on rather few and simple identity elements in tRNA(Ser). The Seryl-tRNA-synthetase interacts with the tRNA(Ser) acceptor stem, which makes this part of the tRNA a valuable structural element for investigating motifs of the protein-RNA complex. We solved the high resolution crystal structures of two tRNA(Ser) acceptor stem microhelices and investigated their interaction with the Seryl-tRNA-synthetase by superposition experiments. The results presented here show that the amino acid side chains Ser151 and Ser156 of the synthetase are interacting in a very similar way with the RNA backbone of the microhelix and that the involved water molecules have almost identical positions within the tRNA/synthetase interface.

Las cadherinas en el diagnóstico histopatológico y pronóstico del carcinoma de células renales / The cadherins in the histopathology diagnosis and prognosis of renal cell carcinoma

El carcinoma de células renales es el cáncer renal más común en el adulto. Se describen 5 tipos histológicos principales, que, en general, muestran al microscopio óptico características que permiten diagnosticarlos. Sin embargo, el solapamiento morfológico observado entre los diferentes tipos y la heterogeneidad histológica dentro del mismo tumor, continúan generando problemas en su clasificación. Algunos marcadores inmunohistoquímicos son empleados en el diagnóstico diferencial de estos carcinomas, pero tienen sus limitaciones. En el presente trabajo, se hizo una revisión de varios estudios, en los que se identificaron alteraciones en la expresión de algunas cadherinas en tejidos renales y líneas celulares con carcinoma de células renales. Estas alteraciones estuvieron asociadas con diferentes estados del desarrollo y progresión del tumor, y sirvieron para predecir el comportamiento neoplásico. Incrementar nuestro conocimiento en este campo, contribuiría al hallazgo de marcadores mucho más específicos para el diagnóstico y pronóstico de estos tumores(AU)

Renal cell carcinoma is the most common adult renal cancer. Five main histological types are described, that in general display characteristic light microscopic features that lead to a correct diagnosis. However, the morphologic overlap between tumors and the histologic heterogeneity within a single tumor continue to create problems in the classification. Some immunohistochemical markers are used in the differential diagnosis of these carcinomas, but they have limitations. In the present work, a review of several studies was made, in which alterations in expression of some cadherins in renal tissue and cell lines with renal cell carcinoma were identified. These alterations were associated with different stages of tumor development and progression, and used to predict the neoplastic behaviour. To increase our knowledge in this field, will contribute to find more specific markers for the diagnosis and prognosis of these tumors(AU)

Las cadherinas en el diagnostico histopatológico y pronostico del carcinoma de células renales / The cadherins in the histopathology diagnosis and prognosis of renal cell carcinoma

El carcinoma de células renales es el cáncer renal más común en el adulto. Se describen 5 tipos histológicos principales, que, en general, muestran al microscopio óptico características que permiten diagnosticarlos. Sin embargo, el solapamiento morfológico observado entre los diferentes tipos y la heterogeneidad histológica dentro del mismo tumor, continúan generando problemas en su clasificación. Algunos marcadores inmunohistoquímicos son empleados en el diagnóstico diferencial de estos carcinomas, pero tienen sus limitaciones. En el presente trabajo, se hizo una revisión de varios estudios, en los que se identificaron alteraciones en la expresión de algunas cadherinas en tejidos renales y líneas celulares con carcinoma de células renales. Estas alteraciones estuvieron asociadas con diferentes estados del desarrollo y progresión del tumor, y sirvieron para predecir el comportamiento neoplásico. Incrementar nuestro conocimiento en este campo, contribuiría al hallazgo de marcadores mucho más específicos para el diagnóstico y pronóstico de estos tumores.

Renal cell carcinoma is the most common adult renal cancer. Five main histological types are described, that in general display characteristic light microscopic features that lead to a correct diagnosis. However, the morphologic overlap between tumors and the histologic heterogeneity within a single tumor continue to create problems in the classification. Some immunohistochemical markers are used in the differential diagnosis of these carcinomas, but they have limitations. In the present work, a review of several studies was made, in which alterations in expression of some cadherins in renal tissue and cell lines with renal cell carcinoma were identified. These alterations were associated with different stages of tumor development and progression, and used to predict the neoplastic behaviour. To increase our knowledge in this field, will contribute to find more specific markers for the diagnosis and prognosis of these tumors.

Tumor-associated angiogenesis and lymphangiogenesis correlate with progression of intrahepatic cholangiocarcinoma.

OBJECTIVES: Little is known about the function of tumor-associated neovascularization in the progression of intrahepatic cholangiocarcinoma (IHC). This study was conducted to evaluate the influence of tumor-associated angiogenesis and lymphangiogenesis on progression of IHC. METHODS: We analyzed tissue specimens of IHC (N=114) by immunohistochemistry using the endothelial-specific antibody CD31 and the lymphendothelial-specific antibody D2-40 and subsequently quantified microvessel density (MVD) and lymphatic microvessel density (LVD). To analyze the influence of tumor-associated angiogenesis and lymphangiogenesis on tumor progression, tumors were allocated according to mean MVD and LVD, respectively, into groups of "high" and "low" MVD and LVD, respectively, and various clinicopathological characteristics as well as recurrence and survival data were analyzed. RESULTS: IHC revealed an induction of tumor-associated angiogenesis and lymphangiogenesis. Tumors of "high" MVD displayed more frequently advanced primary tumor stages and multiple tumor nodes. Furthermore, patients with tumors of "high" MVD had an inferior curative resection rate and suffered more frequently from recurrence. A "high" LVD was correlated with increased nodal spread, and patients with "high" LVD tumors more frequently developed recurrence. In the univariate analysis, MVD and LVD revealed significant influence on survival, and MVD was identified as an independent prognostic factor for survival in the multivariate analysis. The 5-year survival of patients with "low" MVD tumors was 42.1%, compared with 2.2% in patients with "high" MVD tumors (P<0.001). CONCLUSIONS: This study suggests a critical function of tumor-associated angiogenesis and lymphangiogenesis for progression of IHC. Therefore, antiangiogenic and antilymphangiogenic approaches may have therapeutic potency in this tumor entity.

Heterotypic trans-interaction of LI- and E-cadherin and their localization in plasmalemmal microdomains.

Cadherins are calcium-dependent adhesion molecules important for tissue morphogenesis and integrity. LI-cadherin and E-cadherin are the two prominent cadherins in intestinal epithelial cells. Whereas LI-cadherin belongs to the subfamily of 7D (seven-domain)-cadherins defined by their seven extracellular cadherin repeats and short intracellular domain, E-cadherin is the prototype of classical cadherins with five extracellular domains and a highly conserved cytoplasmic part that interacts with catenins and thereby modulates the organization of the cytoskeleton. Here, we report a specific heterotypic trans-interaction of LI- with E-cadherin, two cadherins of distinct subfamilies. Using atomic force microscopy and laser tweezer experiments, the trans-interaction of LI- and E-cadherin was characterized on the single-molecule level and on the cellular level, respectively. This heterotypic interaction showed similar binding strength (20-52 pN at 200-4000 nm/s) and lifetime (0.8 s) as the respective homotypic interactions of LI- and E-cadherin. VE-cadherin, another classical cadherin, did not bind to LI-cadherin. In enterocytes, LI-cadherin and E-cadherin are located in different membrane regions. LI-cadherin is distributed along the basolateral membrane, whereas the majority of E-cadherin is concentrated in adherens junctions. This difference in membrane distribution was also reflected in Chinese hamster ovary cells stably expressing either LI- or E-cadherin. We found that LI-cadherin is localized almost exclusively in cholesterol-rich fractions, whereas E-cadherin is excluded from these membrane fractions. Given their different membrane localization in enterocytes, the heterotypic trans-interaction of LI- and E-cadherin might play a role during development of the intestinal epithelium when the cells do not yet have elaborate membrane specializations.

Intestinal LI-cadherin acts as a Ca2+-dependent adhesion switch.

Cadherins are Ca(2+)-dependent transmembrane glycoproteins that mediate cell-cell adhesion and are important for the structural integrity of epithelia. LI-cadherin and the classical E-cadherin are the predominant two cadherins in the intestinal epithelium. LI-cadherin consists of seven extracellular cadherin repeats and a short cytoplasmic part that does not interact with catenins. In contrast, E-cadherin is composed of five cadherin repeats and a large cytoplasmic domain that is linked via catenins to the actin cytoskeleton. Whereas E-cadherin is concentrated in adherens junctions, LI-cadherin is evenly distributed along the lateral contact area of intestinal epithelial cells. To investigate if the particular structural properties of LI-cadherin result in a divergent homotypic adhesion mechanism, we analyzed the binding parameters of LI-cadherin on the single molecule and the cellular level using atomic force microscopy, affinity chromatography and laser tweezer experiments. Homotypic trans-interaction of LI-cadherin exhibits low affinity binding with a short lifetime of only 1.4 s. Interestingly, LI-cadherin binding responds to small changes in extracellular Ca(2+) below the physiological plasma concentration with a high degree of cooperativity. Thus, LI-cadherin might serve as a Ca(2+)-regulated switch for the adhesive system on basolateral membranes of the intestinal epithelium.

High thrombopoietin concentrations in the cerebrospinal fluid of neonates with sepsis and intraventricular hemorrhage may contribute to brain damage.

Thrombopoietin (TPO) and its receptor (TPOR) are expressed in the central nervous system (CNS). Although TPO shares significant homology with various neurotrophins, recent data indicate a proapoptotic function of TPO in the CNS. In this study, TPO concentrations were analyzed in the cerebrospinal fluid (CSF) of neonates. Human neuroblastoma-derived SH-SY5Y cells were established to elucidate the effects of inflammation and hypoxia on neuronal Tpo expression. TPO was detectable in the CSF of 6 of 15 neonates with bacterial infection/sepsis (median 140, range 2-613 pg/mL), 5 of 9 neonates with posthemorrhagic hydrocephalus (median 31, range 1.4-469 pg/mL), 3 of 4 neonates with posthemorrhagic hydrocephalus plus bacterial infection/sepsis or meningitis (median 97, range 6-397 pg/mL), but not in controls ( n = 3). Neither the presence of detectable TPO nor its level in the CSF significantly correlated with any clinical or laboratory parameter. In SH-SY5Y cells, TPO and TPOR expression was detected by RT-PCR and Western blot analysis. In vitro, interleukin-6 (IL-6) did not significantly change Tpo gene expression. In contrast, Tpo mRNA expression significantly decreased under hypoxia, whereas erythropoietin (EPO) mRNA expression increased. In conclusion, our data provide evidence that in neuronal cells, TPO production is regulated by different mechanisms than in hepatocytes.