A novel protease inhibitor of the alpha2-macroglobulin family expressed in the human epidermis

A2M possesses anti-bacterial functions by recruiting and enhancing phagocytosis through GRP78 in an echinoderm

Alpha-2-macroglobulin (A2M) is an extracellular macromolecule mainly known for its role as a broad-spectrum protease inhibitor in mammals. However, the immune recognition and regulation mechanisms of A2M in invertebrates are still not well investigated. In the current study, the role of sea cucumber Apostichopus japonicus A2M in the regulation of innate immune responses was explored. We found that AjA2M promotes phagocytosis of Vibrio splendidus in coelomocytes of sea cucumber. Then two major functional structural domains of AjA2M, the thioester domain (TED) and the receptor-binding structural domain (RBD) were cloned. It was found that the AjA2M-TED binds to pathogens while causing Vibrio splendidus aggregation; the AjA2M-RBD interacts with the Glucose Regulated Protein 78 (AjGRP78), subsequently AjGRP78 accelerates the degradation of Vibrio splendidus in lysosomes by facilitating polymerisation and rearrangement of the cytoskeleton. Collectively, the findings together suggest that A2M-GRP78 axis mediates immune signaling pathway of phagocytosis and AjA2M has been characterized to play an essential crucial role in antibacterial immune responses of invertebrates.

A chronic pro-inflammatory environment contributes to the physiopathology of actinic lentigines

Actinic lentigines (AL) or age spots, are skin hyperpigmented lesions associated with age and chronic sun exposure. To better understand the physiopathology of AL, we have characterized the inflammation response in AL of European and Japanese volunteers. Gene expression profile showed that in both populations, 10% of the modulated genes in AL versus adjacent non lesional skin (NL), i.e. 31 genes, are associated with inflammation/immune process. A pro-inflammatory environment in AL is strongly suggested by the activation of the arachidonic acid cascade and the plasmin pathway leading to prostaglandin production, along with the decrease of anti-inflammatory cytokines and the identification of inflammatory upstream regulators. Furthermore, in line with the over-expression of genes associated with the recruitment and activation of immune cells, immunostaining on skin sections revealed a significant infiltration of CD68+ macrophages and CD4+ T-cells in the dermis of AL. Strikingly, investigation of infiltrated macrophage subsets evidenced a significant increase of pro-inflammatory CD80+/CD68+ M1 macrophages in AL compared to NL. In conclusion, a chronic inflammation, sustained by pro-inflammatory mediators and infiltration of immune cells, particularly pro-inflammatory M1 macrophages, takes place in AL. This pro-inflammatory loop should be thus broken to normalize skin and improve the efficacy of age spot treatment.

Exploring Prognostic Gene Factors in Breast Cancer via Machine Learning

Breast cancer remains the most prevalent cancer in women. To date, its underlying molecular mechanisms have not been fully uncovered. The determination of gene factors is important to improve our understanding on breast cancer, which can correlate the specific gene expression and tumor staging. However, the knowledge in this regard is still far from complete. Thus, this study aimed to explore these knowledge gaps by analyzing existing gene expression profile data from 3149 breast cancer samples, where each sample was represented by the expression of 19,644 genes and classified into Nottingham histological grade (NHG) classes (Grade 1, 2, and 3). To this end, a machine learning-based framework was designed. First, the profile data were analyzed by using seven feature ranking algorithms to evaluate the importance of features (genes). Seven feature lists were generated, each of which sorted features in accordance with feature importance evaluated from a special aspect. Then, the incremental feature selection method was applied to each list to determine essential features for classification and building efficient classifiers. Consequently, overlapping genes, such as AURKA, CBX2, and MYBL2, were deemed as potentially related to breast cancer malignancy and prognosis, indicating that such genes were identified to be important by multiple feature ranking algorithms. In addition, the study formulated classification rules to reflect special gene expression patterns for three NHG classes. Some genes and rules were analyzed and supported by recent literature, providing new references for studying breast cancer.

Engineering New Protease Inhibitors Using α2-Macroglobulin

Protease inhibitors of the alpha-macroglobulin family (αM) have a unique mechanism that allows them to trap proteases that is dependent not on the protease's class, but rather on its cleavage specificity. Proteases trigger a conformational change in the αM protein by cleaving within a "bait region," resulting in the sequestering of the protease inside the αM molecule. This nonspecific inhibitory mechanism appears to have arisen early in the αM family, and the broad protease-trapping capacity that it allows may play a role in pathogen defense.Human α2-macroglobulin (A2M) is a tetrameric αM whose bait region is permissive to cleavage by most proteases, making it a broad-spectrum protease inhibitor. Recent work has demonstrated that the inhibitory capacity of A2M derives directly from its bait region sequence: modifying the bait region sequence to introduce or remove protease cleavage sites will modify A2M's inhibition of the relevant proteases accordingly. Thus, changing the amino acid sequence of the bait region presents an effective avenue for protein engineering of new protease inhibitors if the substrate specificity of the target protease is known. The design of new A2M-based protease inhibitors with tailored inhibitory capacities has potential applications in basic research and the clinic. In this chapter, we describe the general approach and considerations for the bait region engineering of A2M.

A2ML1 Inhibits Esophageal Squamous Cell Carcinoma Progression and Serves as a Novel Prognostic Biomarker

Studies have established a correlation between α2-macroglobulin-like 1 (A2ML1) and the prognosis of lung, pancreatic, and breast cancers; however, research on its involvement in the pathogenesis of esophageal carcinoma remains limited. Therefore, in this study, we aimed to investigate the role of A2ML1 in the progression of esophageal squamous cell carcinoma (ESCC). Immunohistochemical staining was employed to assess the expression level of A2ML1 protein in both tumor and adjacent normal tissues of patients with ESCC. The Kaplan-Meier method, along with univariate and multivariate Cox risk ratio analyses, was used to determine survival rates and prognostic factors. Furthermore, two human ESCC cell lines, KYSE30 and KYSE150, were used to assess the effect of A2ML1 overexpression on cell proliferation and apoptosis. A human apoptosis antibody kit was also used to analyze the downstream action proteins of A2ML1, and a nude mouse xenotransplantation model was used to evaluate the effect of A2ML1 on ESCC tumorigenesis in vivo. The protein level of A2ML1 in ESCC tissues was significantly lower than that in normal esophageal tissues, and higher A2ML1 protein levels were associated with smaller ESCC tumor sizes and improved tumor-specific survival rates. Multivariate analysis established A2ML1 as a novel independent prognostic factor for ESCC. Moreover, A2ML1 overexpression significantly inhibited ESCC cell proliferation and promoted apoptosis. A2ML1 consistently inhibited tumor growth in mouse models. Furthermore, the human apoptotic antibody kit results showed increased expression of the proliferation-inhibiting protein p21 downstream of KYSE150 cells overexpressing A2ML1. Our findings demonstrate that a correlation exists between A2ML1 and ESCC prognosis and that A2ML1 plays an antitumor role in ESCC progression. This study underscores the potential of A2ML1 as a novel biomarker for predicting the prognosis of ESCC.

RASopathies and cardiac manifestations

As binary switches, RAS proteins switch to an ON/OFF state during signaling and are on a leash under normal conditions. However, in RAS-related diseases such as cancer and RASopathies, mutations in the genes that regulate RAS signaling or the RAS itself permanently activate the RAS protein. The structural basis of this switch is well understood; however, the exact mechanisms by which RAS proteins are regulated are less clear. RAS/MAPK syndromes are multisystem developmental disorders caused by germline mutations in genes associated with the RAS/mitogen-activated protein kinase pathway, impacting 1 in 1,000-2,500 children. These include a variety of disorders such as Noonan syndrome (NS) and NS-related disorders (NSRD), such as cardio facio cutaneous (CFC) syndrome, Costello syndrome (CS), and NS with multiple lentigines (NSML, also known as LEOPARD syndrome). A frequent manifestation of cardiomyopathy (CM) and hypertrophic cardiomyopathy associated with RASopathies suggest that RASopathies could be a potential causative factor for CM. However, the current supporting evidence is sporadic and unclear. RASopathy-patients also display a broad spectrum of congenital heart disease (CHD). More than 15 genes encode components of the RAS/MAPK signaling pathway that are essential for the cell cycle and play regulatory roles in proliferation, differentiation, growth, and metabolism. These genes are linked to the molecular genetic pathogenesis of these syndromes. However, genetic heterogeneity for a given syndrome on the one hand and alleles for multiple syndromes on the other make classification difficult in diagnosing RAS/MAPK-related diseases. Although there is some genetic homogeneity in most RASopathies, several RASopathies are allelic diseases. This allelism points to the role of critical signaling nodes and sheds light on the overlap between these related syndromes. Even though considerable progress has been made in understanding the pathophysiology of RASopathy with the identification of causal mutations and the functional analysis of their pathophysiological consequences, there are still unidentified causal genes for many patients diagnosed with RASopathies.

Continuous activation of the IL-17F driven inflammatory pathway in acute and chronic digital dermatitis lesions in dairy cattle

Objectives of the present study were to get a deeper insight into the course of the inflammatory pathways of digital dermatitis lesions in dairy cattle by investigating the gene expression patterns throughout the different clinical stages (M0 to M4.1) of the disease. Normal skin samples (M0) were used as a reference for comparing the gene expression levels in the other M-stages through RNA Seq-technology. Principal component analysis revealed a distinct gene expression pattern associated with digital dermatitis lesions in comparison to healthy skin with a further clustering of the acute M1, M2 and M4.1 stages versus the chronic M3 and M4 stages. The majority of the up-and downregulated genes in the acute and chronic stages can be placed into a common 'core' set of genes involved in inflammation, such as A2ML1, PI3, CCL11 and elafin-like protein, whereas the most downregulated genes included keratins and anti-inflammatory molecules such as SCGB1D and MGC151921. Pathway analysis indicated the activation of the pro-inflammatory IL-17 signaling pathway in all the M stages through the upregulation of IL-17F. These results indicate that digital dermatitis is associated with an excessive inflammatory immune response concomitant with a disrupted skin barrier and impaired wound repair mechanism. Importantly, despite their macroscopically healed appearance, a significant inflammatory response (Padj < 0.05) was still measurable in the M3 and M4 lesions, potentially explaining the frequent re-activation of such lesions.

Cryo-EM structures reveal the dynamic transformation of human alpha-2-macroglobulin working as a protease inhibitor

Human alpha-2-macroglobulin is a well-known inhibitor of a broad spectrum of proteases and plays important roles in immunity, inflammation, and infections. Here, we report the cryo-EM structures of human alpha-2-macroglobulin in its native state, induced state transformed by its authentic substrate, human trypsin, and serial intermediate states between the native and fully induced states. These structures exhibit distinct conformations, which reveal the dynamic transformation of alpha-2-macro-globulin that acts as a protease inhibitor. The results shed light on the molecular mechanism of alpha-2-macroglobulin in entrapping substrates.

Cryo-EM structures of human A2ML1 elucidate the protease-inhibitory mechanism of the A2M family

A2ML1 is a monomeric protease inhibitor belonging to the A2M superfamily of protease inhibitors and complement factors. Here, we investigate the protease-inhibitory mechanism of human A2ML1 and determine the structures of its native and protease-cleaved conformations. The functional inhibitory unit of A2ML1 is a monomer that depends on covalent binding of the protease (mediated by A2ML1’s thioester) to achieve inhibition. In contrast to the A2M tetramer which traps proteases in two internal chambers formed by four subunits, in protease-cleaved monomeric A2ML1 disordered regions surround the trapped protease and may prevent substrate access. In native A2ML1, the bait region is threaded through a hydrophobic channel, suggesting that disruption of this arrangement by bait region cleavage triggers the extensive conformational changes that result in protease inhibition. Structural comparisons with complement C3/C4 suggest that the A2M superfamily of proteins share this mechanism for the triggering of conformational change occurring upon proteolytic activation.

A2ML1 is a human protease inhibitor belonging to the A2M protein family. In this study, the authors determine structures of A2ML1 before and after protease inhibition and investigate its mechanism of action.

Complementary liver and serum protein profile in wild boars infected by the giant liver fluke Fascioloides magna using tandem mass tags quantitative approach

Liver fluke, Fascioloides magna, is an important non-native parasite introduced to Europe, posing a threat to survival of local wildlife populations. The aim of this study was to assess the serum and liver protein profile of control and F. magna infected wild boars, by means of shotgun tandem mass tag - based quantitative high resolution proteomics approach. In serum, 4 differentially abundant proteins were found out of total 1073 identified, while in liver from 3520 identified proteins, 116 were differentially abundant between healthy and F. magna infected wild boars. Pathway analysis revealed that most of the proteins differing in abundance are involved in metabolism, biological oxidations, cellular responses to stimuli, fatty acid metabolism, and others. Validation of proteomic results was performed for paraoxonase-1, ceruloplasmin, glutathione S-transferase and liver enzymes by ELISA and automated assays. Complementary analysis of liver and serum in F. magna infection enabled insight into changes of proteome profile of the host at local and sistemic level. Our findings showed that chronic infection with F. magna is associated with immune response in host, oxidative stress and metabolomic changes in liver. SIGNIFICANCE: Liver fluke infections are recognised as worldwide neglected diseases with considerable veterinary and public health importance. Pathological changes, clinical signs and outcome of F. magna infection are strongly related to the type of final hosts and their different tolerance to infection. In order to gain insight into host-parasite interactions in wild boars, dead-end host for F. magna, we assessed proteomics profile of serum and liver of control animals and those infected with F. magna. Proteomics analysis of serum and liver in parallel showed as advantageous and beneficial, demonstrating protein alterations mainly at local level. Bioinformatics analysis enabled elucidation of molecular pathways associated with F. magna infection. Identification and validation of proteins associated with infection may have added value to current tools for efficient liver fluke control.

Investigation of the Molecular Mechanisms of Antioxidant Damage and Immune Response Downregulation in Liver of Coilia nasus Under Starvation Stress

Commercial fishing of estuarine tapertail anchovy (Coilia nasus), an important anadromous fish species in the Yangtze River of China, has been prohibited due to the serious damage overfishing has caused to the wild population. Research regarding the energy metabolism is important for migratory fish to ensure the continuation of their existence. In this study, we performed, for the first time, a comparative transcriptome analysis of the liver of C. nasus subjected to long-term starvation stress. The results indicated that the damaging effects involved downregulation of the antioxidant capacity and immune response. The positive response to starvation involved upregulation of the anti-allergy and anticancer capacity, which supports the function of starvation in cancer inhibition, as has also been determined for human beings. This study revealed regulatory pathways, differentially expressed genes (DEGs), and mechanisms leading to damage of the liver in C. nasus affected by starvation. This research contributes information for the further study of the energy metabolism mechanism of C. nasus and provides a theoretical reference for starvation metabolism research of other fish species and even human beings.

α2-Macroglobulin-like protein 1 can conjugate and inhibit proteases through their hydroxyl groups, because of an enhanced reactivity of its thiol ester

Proteins in the α-macroglobulin (αM) superfamily use thiol esters to form covalent conjugation products upon their proteolytic activation. αM protease inhibitors use theirs to conjugate proteases and preferentially react with primary amines (e.g. on lysine side chains), whereas those of αM complement components C3 and C4B have an increased hydroxyl reactivity that is conveyed by a conserved histidine residue and allows conjugation to cell surface glycans. Human α2-macroglobulin-like protein 1 (A2ML1) is a monomeric protease inhibitor but has the hydroxyl reactivity-conveying histidine residue. Here, we have investigated the role of hydroxyl reactivity in a protease inhibitor by comparing recombinant WT A2ML1 and the A2ML1 H1084N mutant in which this histidine is removed. Both of A2ML1s' thiol esters were reactive toward the amine substrate glycine, but only WT A2ML1 reacted with the hydroxyl substrate glycerol, demonstrating that His-1084 increases the hydroxyl reactivity of A2ML1's thiol ester. Although both A2ML1s conjugated and inhibited thermolysin, His-1084 was required for the conjugation and inhibition of acetylated thermolysin, which lacks primary amines. Using MS, we identified an ester bond formed between a thermolysin serine residue and the A2ML1 thiol ester. These results demonstrate that a histidine-enhanced hydroxyl reactivity can contribute to protease inhibition by an αM protein. His-1084 did not improve A2ML1's protease inhibition at pH 5, indicating that A2ML1's hydroxyl reactivity is not an adaption to its acidic epidermal environment.

The clinical significance of A2ML1 variants in Noonan syndrome has to be reconsidered

The RASopathies are a group of clinically and genetically heterogeneous developmental disorders caused by dysregulation of the RAS/MAPK signalling pathway. Variants in several components and regulators of this pathway have been identified as the pathogenetic cause. In 2015, missense variants in A2ML1 were reported in three unrelated families with clinical diagnosis of Noonan syndrome (NS) and a zebrafish model was presented showing heart and craniofacial defects similar to those caused by a NS-associated Shp2 variant. However, a causal role of A2ML1 variants in NS has not been confirmed since. Herein, we report on 15 individuals who underwent screening of RASopathy-associated genes and were found to carry rare variants in A2ML1, including variants previously proposed to be causative for NS. In cases where parental DNA was available, the respective A2ML1 variant was found to be inherited from an unaffected parent. Seven index patients carrying an A2ML1 variant presented with an alternate disease-causing genetic aberration. These findings underscore that current evidence is insufficient to support a causal relation between variants in A2ML1 and NS, questioning the inclusion of A2ML1 screening in diagnostic RASopathy testing.

Digenic inheritance of subclinical variants in Noonan Syndrome patients: an alternative pathogenic model?

Noonan syndrome (NS) is an autosomal-dominant disorder with variable expressivity and locus heterogeneity. Despite several RAS pathway genes were implicated in NS, 20–30% of patients remain without molecular diagnosis, suggesting the involvement of further genes or multiple mechanisms. Eight patients out of 60, negative for conventional NS mutation analysis, with heterogeneous NS phenotype were investigated by means of target resequencing of 26 RAS/MAPK pathway genes. A trio was further characterized by means of whole-exome sequencing. Protein modeling and in silico prediction of protein stability allowed to identify possible pathogenic RAS pathway variants in four NS patients. A new c.355T>C variant in LZTR1 was found in patient 43. Two patients co-inherited variants in LRP1 and LZTR1 (patient 53), or LRP1 and SOS1 genes (patient 67). The forth patient (56) carried a compound heterozygote of RASAL3 gene variants and also an A2ML1 variant. While these subclinical variants are singularly present in healthy parents, they co-segregate in patients, suggesting their addictive effect and supporting a digenic inheritance, as alternative model to a more common monogenic transmission. The ERK1/2 and SAPK/JNK activation state, assessed on immortalized lymphocytes from patients 53 and 67 showed highest phosphorylation levels compared to their asymptomatic parents. These findings together with the lack of their co-occurrence in the 1000Genomes database strengthen the hypothesis of digenic inheritance in a subset of NS patients. This study suggests caution in the exclusion of subclinical variants that might play a pathogenic role providing new insights for alternative hereditary mechanisms.

Detection of autoantibodies against alpha-2-macroglobulin-like 1 in paraneoplastic pemphigus sera utilizing novel green fluorescent protein-based immunoassays

BACKGROUND

Paraneoplastic pemphigus (PNP) is a devastating autoimmune multiorgan syndrome associated with autoantibodies against several autoantigens, including the alpha-2-macroglobulin-like-1 (A2ML1). A2ML1 is recognized by up to 70 % of PNP sera. The currently recommended techniques for serological diagnosis of PNP are inadequate to detect anti-A2ML1 antibodies.

OBJECTIVES

To develop novel assays which allow to easily and reliably detect anti-A2ML1 autoantibodies in PNP sera.

METHODS

We produced full-length A2ML1 in fusion with enhanced green fluorescent protein (EGFP-A2ML1) in transfected human embryonic kidney 293 T cells. The recombinant protein was used as fluorescent ligand for immunoprecipitation studies. We further developed an enzyme-linked immunosorbent assay (ELISA) by immobilizing EGFP-A2ML1 on 96-well plates.

RESULTS

A2ML1-positive PNP sera were able to immunoprecipitate EGFP-A2ML1. Direct measurement of fluorescence in immunoprecipitates correlates with the relative levels of anti-A2ML1 antibodies in the PNP sera. By the novel ELISA, based on the determined best cut-off value, 61 % of the tested 36 PNP sera were A2ML1 positive with a specificity of 88.9 % and a sensitivity of 95 %. The 20 tested normal sera (NHS) were negative, while 2 (10 %) of 20 pemphigus vulgaris and 3 (15 %) of 20 bullous pemphigoid sera showed borderline values.

CONCLUSIONS

Our novel immunoassays enable rapid stratification of PNP patients. The novel green fluorescent protein-based ELISA utilizing an active eukaryotic A2ML1 is highly sensitive and reliable and, hence, is useful for a better understanding of the immunological background of PNP. This approach may be easily applied for the rapid detection of antibodies to various other antigens.

Genomics of Otitis Media (OM): Molecular Genetics Approaches to Characterize Disease Pathophysiology

Otitis media (OM) is an infective and inflammatory disorder known to be a major cause of hearing impairment across all age groups. Both acute and chronic OM result in substantial healthcare utilization related to antibiotic prescription and surgical procedures necessary for its management. Although several studies provided evidence of genetics playing a significant role in the susceptibility to OM, we had limited knowledge about the genes associated with OM until recently. Here we have summarized the known genetic factors that confer susceptibility to various forms of OM in mice and in humans and their genetic load, along with associated cellular signaling pathways. Spotlighted in this review are fucosyltransferase (FUT) enzymes, which have been implicated in the pathogenesis of OM. A comprehensive understanding of the functions of OM-associated genes may provide potential opportunities for its diagnosis and treatment.

Human PZP and common marmoset A2ML1 as pregnancy related proteins

While pregnancy-related proteins (PRP) are known to contribute to immunotolerance during pregnancy, their significance to development of invasive placenta is unclear. We compared PRP expression in humans and the common marmoset (Callithrix jacchus), a new-world monkey. Invasive placenta was observed at the maternal-foetal interface of marmoset placenta from green fluorescent protein (GFP)-expressing foetus and wild type mother. The pregnancy zone protein (PZP) and alpha-2 macroglobulin-like 1 (A2ML1) proteins exhibited the most prominent increase in expression during the second trimester in humans and marmoset, respectively. In humans, PZP accumulated at the maternal-foetal interface and A2ML1 accumulated in the amnion. Similarly, A2ML1 mRNA was detected in marmoset placenta. These proteins belong to the A2M family of protease inhibitors, and both PZP and A2ML1 share around 90% homology between human and marmoset and have highly conserved structures. However, the protease-reacting bait regions of the proteins had lower homology (56.8–60.7% in proteins) relative to the rest of the sequence. Notably, the cleavage site of a proinflammatory proline-endopeptidase was preserved in human PZP and marmoset A2ML1. These proteins contain multiple sites that are cleaved by proteases involving proline-endopeptidase. Systemic regulation of these A2M family proteins may be important in animals with invasive placenta.

Non‑invasive proteome‑wide quantification of skin barrier‑related proteins using label‑free LC‑MS/MS analysis

A number of epidermal proteins are closely related to skin barrier function, the abnormalities of which can lead to specific skin diseases. These proteins must be quantified to further investigate the changes in the skin barrier between healthy and disease states. However, the non-invasive and proteome-wide quantification of skin proteins without any labelling steps remains a challenge. In this study, 3M medical adhesive tapes were used to obtain skin samples from volunteers. Proteins were extracted from fresh skin samples and digested with trypsin. Each tryptic peptide was analysed in three replicates using liquid chromatography with tandem mass spectrometry analysis and label-free quantification. The data were searched against the Human Universal Protein Resource (UniProt) to match with known proteins. Using this method, 1,157 skin proteins recorded in the UniProt were quantified. A total of 50 identical proteins were identified in the three replicate analyses of all samples with no significant differences in abundance. The results provided an objective metric for further study of skin ageing and various skin diseases. Specifically, the non-invasive proteome-wide method used in this study can be applied to future studies of skin diseases related to barrier destruction by monitoring the changes in the levels of epidermal proteins.

Differentially expressed genes and key molecules of BRCA1/2-mutant breast cancer: evidence from bioinformatics analyses

Background

BRCA1 and BRCA2 genes are currently proven to be closely related to high lifetime risks of breast cancer. To date, the closely related genes to BRCA1/2 mutations in breast cancer remains to be fully elucidated. This study aims to identify the gene expression profiles and interaction networks influenced by BRCA1/2 mutations, so as to reflect underlying disease mechanisms and provide new biomarkers for breast cancer diagnosis or prognosis.

Methods

Gene expression profiles from The Cancer Genome Atlas (TCGA) database were downloaded and combined with cBioPortal website to identify exact breast cancer patients with BRCA1/2 mutations. Gene set enrichment analysis (GSEA) was used to analyze some enriched pathways and biological processes associated BRCA mutations. For BRCA1/2-mutant breast cancer, wild-type breast cancer and corresponding normal tissues, three independent differentially expressed genes (DEGs) analysis were performed to validate potential hub genes with each other. Protein-protein interaction (PPI) networks, survival analysis and diagnostic value assessment helped identify key genes associated with BRCA1/2 mutations.

Results

The regulation process of cell cycle was significantly enriched in mutant group compared with wild-type group. A total of 294 genes were identified after analysis of DEGs between mutant patients and wild-type patients. Interestingly, by the other two comparisons, we identified 43 overlapping genes that not only significantly expressed in wild-type breast cancer patients relative to normal tissues, but more significantly expressed in BRCA1/2-mutant breast patients. Based on the STRING database and cytoscape software, we constructed a PPI network using 294 DEGs. Through topological analysis scores of the PPI network and 43 overlapping genes, we sought to select some genes, thereby using survival analysis and diagnostic value assessment to identify key genes pertaining to BRCA1/2-mutant breast cancer. CCNE1, NPBWR1, A2ML1, EXO1 and TTK displayed good prognostic/diagnostic value for breast cancer and BRCA1/2-mutant breast cancer.

Conclusion

Our research provides comprehensive and new insights for the identification of biomarkers connected with BRCA mutations, availing diagnosis and treatment of breast cancer and BRCA1/2-mutant breast cancer patients.

Peptidase inhibitors in tick physiology

Peptidase inhibitors regulate a wide range of physiological processes involved in the interaction between hematophagous parasites and their hosts, including tissue remodeling, the immune response and blood coagulation. In tick physiology, peptidase inhibitors have a crucial role in adaptation to improve parasitism mechanisms, facilitating blood feeding by interfering with defense-related host peptidases. Recently, a larger number of studies on this topic led to the description of several new tick inhibitors displaying interesting novel features, for example a role in pathogen transmission to the host. A comprehensive review discussing these emerging concepts can therefore shed light on peptidase inhibitor functions, their relevance to tick physiology and their potential applications. Here, we summarize and examine the general characteristics, functional diversity and action of tick peptidase inhibitors with known physiological roles in the tick-host-pathogen interaction.

TRIM58/cg26157385 methylation is associated with eight prognostic genes in lung squamous cell carcinoma

The present study aimed to analyze the differentially expressed genes related to the tripartite motif containing 58 (TRIM58)/cg26157385 methylation sites, and consequently to provide theoretical basis for elucidating the influence of TRIM58/cg26157385 methylation on lung cancer prognosis. Methylation-sequencing information, mRNA expression profiling data and clinical data were downloaded from cBioPortal database to screen out candidate genes related to the methylation of TRIM58/cg26157385 in squamous cell lung carcinoma. The differentially expressed genes related to TRIM58 methylation were extracted form both training dataset and validation dataset. Cox regression analysis, risk scoring system construction, correlation analysis between the expression value of genes and clinical information were conducted to reveal TRIM58 methylation-related factors. Additionally, GO function analysis and KEGG pathway enrichment analysis were performed. Based on their expression level and the corresponding survival information for 347 out of 370 samples with squamous cell lung carcinoma, 183 genes significantly associated with prognosis were gained, and the top 8 ones, including alpha-2-macroglobulin-like 1 (A2ML1), cyclin-E1 (CCNE1), COBL, establishment of sister chromatid cohesion N-acetyltransferase 2 (ESCO2), G protein-coupled receptor 115 (GPR115), matrix metalloproteinases 10 (MMP10), OVO homologue-like 1 (OVOL1) and secretoglobin family 1A member 1 (SCGB1A1), were candidate signature genes significantly correlated with TRIM58 methylation. Furthermore, targeted therapy was significantly correlated with prognosis. Functional enrichment analysis demonstrated that the proliferation and differentiation of epidermal cells in lung squamous cell carcinoma patients were abnormal and the homeostasis was disturbed. Eight genes, including A2ML1, CCNE1, COBL, ESCO2, GPR115, MMP10, OVOL1 and SCGB1A1, were significantly related to TRIM58 methylation and treatment of lung squamous cell carcinoma, and may be used as potential prognostic biomarkers. The present study would help to elucidate the influence of TRIM58/cg26157385 methylation on lung cancer prognosis.

Clearance of a persistent picornavirus infection is associated with enhanced pro-apoptotic and cellular immune responses

Long-term persistent viral infections cause substantial morbidity and associated economic losses in human and veterinary contexts. Yet, the mechanisms associated with establishment of persistent infections are poorly elucidated. We investigated immunomodulatory mechanisms associated with clearance versus persistence of foot-and-mouth disease virus (FMDV) in micro-dissected compartments of the bovine nasopharynx by microarray. The use of laser-capture microdissection allowed elucidation of differential gene regulation within distinct anatomic compartments critical to FMDV infection. Analysis of samples from transitional and persistent phases of infection demonstrated significant differences in transcriptome profiles of animals that cleared infection versus those that became persistently infected carriers. Specifically, it was demonstrated that clearance of FMDV from the nasopharyngeal mucosa was associated with upregulation of targets associated with activation of T cell-mediated immunity. Contrastingly, gene regulation in FMDV carriers suggested inhibition of T cell activation and promotion of Th2 polarization. These findings were corroborated by immunofluorescence microscopy which demonstrated relative abundance of CD8⁺ T cells in the nasopharyngeal mucosa in association with clearance of FMDV. The findings presented herein emphasize that a critical balance between Th1 and Th2 -mediated immunity is essential for successful clearance of FMDV infection and should be considered for development of next-generation vaccines and antiviral products.

Structural and functional insight into pan-endopeptidase inhibition by α2-macroglobulins

Peptidases must be exquisitely regulated to prevent erroneous cleavage and one control is provided by protein inhibitors. These are usually specific for particular peptidases or families and sterically block the active-site cleft of target enzymes using lock-and-key mechanisms. In contrast, members of the +1400-residue multi-domain α2-macroglobulin inhibitor family (α2Ms) are directed against a broad spectrum of endopeptidases of disparate specificities and catalytic types, and they inhibit their targets without disturbing their active sites. This is achieved by irreversible trap mechanisms resulting from large conformational rearrangement upon cleavage in a promiscuous bait region through the prey endopeptidase. After decades of research, high-resolution structural details of these mechanisms have begun to emerge for tetrameric and monomeric α2Ms, which use 'Venus-flytrap' and 'snap-trap' mechanisms, respectively. In the former, represented by archetypal human α2M, inhibition is exerted through physical entrapment in a large cage, in which preys are still active against small substrates and inhibitors that can enter the cage through several apertures. In the latter, represented by a bacterial α2M from Escherichia coli, covalent linkage and steric hindrance of the prey inhibit activity, but only against very large substrates.

Keeping It All Going-Complement Meets Metabolism

The complement system is an evolutionary old and crucial component of innate immunity, which is key to the detection and removal of invading pathogens. It was initially discovered as a liver-derived sentinel system circulating in serum, the lymph, and interstitial fluids that mediate the opsonization and lytic killing of bacteria, fungi, and viruses and the initiation of the general inflammatory responses. Although work performed specifically in the last five decades identified complement also as a critical instructor of adaptive immunity—indicating that complement’s function is likely broader than initially anticipated—the dominant opinion among researchers and clinicians was that the key complement functions were in principle defined. However, there is now a growing realization that complement activity goes well beyond “classic” immune functions and that this system is also required for normal (neuronal) development and activity and general cell and tissue integrity and homeostasis. Furthermore, the recent discovery that complement activation is not confined to the extracellular space but occurs within cells led to the surprising understanding that complement is involved in the regulation of basic processes of the cell, particularly those of metabolic nature—mostly via novel crosstalks between complement and intracellular sensor, and effector, pathways that had been overlooked because of their spatial separation. These paradigm shifts in the field led to a renaissance in complement research and provide new platforms to now better understand the molecular pathways underlying the wide-reaching effects of complement functions in immunity and beyond. In this review, we will cover the current knowledge about complement’s emerging relationship with the cellular metabolism machinery with a focus on the functional differences between serum-circulating versus intracellularly active complement during normal cell survival and induction of effector functions. We will also discuss how taking a closer look into the evolution of key complement components not only made the functional connection between complement and metabolism rather “predictable” but how it may also give clues for the discovery of additional roles for complement in basic cellular processes.

α2-Macroglobulins: Structure and Function

α₂-macroglobulins are broad-spectrum endopeptidase inhibitors, which have to date been characterised from metazoans (vertebrates and invertebrates) and Gram-negative bacteria. Their structural and biochemical properties reveal two related modes of action: the "Venus flytrap" and the "snap-trap" mechanisms. In both cases, peptidases trigger a massive conformational rearrangement of α₂-macroglobulin after cutting in a highly flexible bait region, which results in their entrapment. In some homologs, a second action takes place that involves a highly reactive β-cysteinyl-γ-glutamyl thioester bond, which covalently binds cleaving peptidases and thus contributes to the further stabilization of the enzyme:inhibitor complex. Trapped peptidases are still active, but have restricted access to their substrates due to steric hindrance. In this way, the human α₂-macroglobulin homolog regulates proteolysis in complex biological processes, such as nutrition, signalling, and tissue remodelling, but also defends the host organism against attacks by external toxins and other virulence factors during infection and envenomation. In parallel, it participates in several other biological functions by modifying the activity of cytokines and regulating hormones, growth factors, lipid factors and other proteins, which has a great impact on physiology. Likewise, bacterial α₂-macroglobulins may participate in defence by protecting cell wall components from attacking peptidases, or in host-pathogen interactions through recognition of host peptidases and/or antimicrobial peptides. α₂-macroglobulins are more widespread than initially thought and exert multifunctional roles in both eukaryotes and prokaryotes, therefore, their on-going study is essential.

Noonan syndrome-causing genes: Molecular update and an assessment of the mutation rate

Noonan syndrome is a common autosomal dominant disorder characterized by short stature, congenital heart disease and facial dysmorphia with an incidence of 1/1000 to 2500 live births. Up to now, several genes have been proven to be involved in the disturbance of the transduction signal through the RAS-MAP Kinase pathway and the manifestation of Noonan syndrome. The first gene described was PTPN11, followed by SOS1, RAF1, KRAS, BRAF, NRAS, MAP2K1, and RIT1, and recently SOS2, LZTR1, and A2ML1, among others. Progressively, the physiopathology and molecular etiology of most signs of Noonan syndrome have been demonstrated, and inheritance patterns as well as genetic counseling have been established. In this review, we summarize the data concerning clinical features frequently observed in Noonan syndrome, and then, we describe the molecular etiology as well as the physiopathology of most Noonan syndrome-causing genes. In the second part of this review, we assess the mutational rate of Noonan syndrome-causing genes reported up to now in most screening studies. This review should give clinicians as well as geneticists a full view of the molecular aspects of Noonan syndrome and the authentic prevalence of the mutational events of its causing-genes. It will also facilitate laying the groundwork for future molecular diagnosis research, and the development of novel treatment strategies.

Pathogenetics of the RASopathies

The RASopathies are defined as a group of medical genetics syndromes that are caused by germ-line mutations in genes that encode components or regulators of the Ras/mitogen-activated protein kinase (MAPK) pathway. Taken together, the RASopathies represent one of the most prevalent groups of malformation syndromes affecting greater than 1 in 1,000 individuals. The Ras/MAPK pathway has been well studied in the context of cancer as it plays essential roles in growth, differentiation, cell cycle, senescence and apoptosis, all of which are also critical to normal development. The consequence of germ-line dysregulation leads to phenotypic alterations of development. RASopathies can be caused by several pathogenetic mechanisms that ultimately impact or alter the normal function and regulation of the MAPK pathway. These pathogenetic mechanisms can include functional alteration of GTPases, Ras GTPase-activating proteins, Ras guanine exchange factors, kinases, scaffolding or adaptor proteins, ubiquitin ligases, phosphatases and pathway inhibitors. Although these mechanisms are diverse, the common underlying biochemical phenotype shared by all the RASopathies is Ras/MAPK pathway activation. This results in the overlapping phenotypic features among these syndromes.

Expansion of the RASopathies

The Ras/mitogen activated protein kinase (MAPK) pathway is essential in the regulation of cell cycle, differentiation, growth, cell senescence and apoptosis, all of which are critical to normal development. A class of neurodevelopmental disorders, RASopathies, is caused by germline mutations in genes of the Ras/MAPK pathway. Through the use of whole exome sequencing and targeted sequencing of selected genes in cohorts of panel-negative RASopathy patients, several new genes have been identified. These include: RIT1, SOS2, RASA2, RRAS and SYNGAP1, that likely represent new, albeit rare, causative RASopathy genes. In addition, A2ML1, LZTR1, MYST4, SPRY1 and MAP3K8 may represent new rare genes for RASopathies, but, additional functional studies regarding the mutations are warranted. In addition, recent reports have demonstrated that chromosomal copy number variation in regions encompassing Ras/MAPK pathway genes may be a novel pathogenetic mechanism expanding the RASopathies.

Discovery, structural characterization and functional analysis of alpha-2-macroglobulin, a novel immune-related molecule from Holothuria atra

The non-specific protease inhibitor alpha-2-macroglobulin (A2M) is a key macromolecular glycoprotein that involved in host immune defense against pathogens in vertebrates and invertebrates. However, no research regarding A2M has been developed in echinoderms to date. In this study, the full-length cDNA of A2M was cloned from the sea cucumber (Holothuria atra), which is a tropical species widely distributed along the coasts of the South China Sea and designated HaA2M. HaA2M possesses all three conserved functional domains of known A2M proteins, including the bait region domain, thioester domain and receptor-binding domain. Compared to fish and shrimp A2Ms, the histidine residue from the catalytical regions is well conserved in HaA2M. HaA2M mRNA was predominantly expressed in coelomocytes and, to a lesser extent, in the body wall, intestine and respiratory tree. A2M activity was detected in the coelomic fluids of H. atra. The mRNA expression and activity levels were investigated in the major immune tissues and coelomic fluids of H. atra after challenge with inactivated Vibrio alginolyticus or polyriboinosinic polyribocytidylic acid [Poly (I: C)]. RNA interference (RNAi)-mediated knockdown of HaA2M resulted in a significant reduction of HaA2M gene transcript level (86%). RNAi-mediated silencing of HaA2M gene significantly decreased the A2M activity (38%) and increased the number of viable bacteria (2.8-fold) in the coelomic fluids of H. atra infected by V. alginolyticus. Our study, as a whole, supplied the evidences for HaA2M as an immune-relevant molecule and it might have multiple functions in the innate immune system of H. atra.

Recent advances in RASopathies

RASopathies or RAS/mitogen-activated protein kinase (MAPK) syndromes are a group of phenotypically overlapping syndromes caused by germline mutations that encode components of the RAS/MAPK signaling pathway. These disorders include neurofibromatosis type I, Legius syndrome, Noonan syndrome, Noonan syndrome with multiple lentigines (formerly called LEOPARD syndrome), Costello syndrome, cardiofaciocutaneous (CFC) syndrome, Noonan-like syndrome, hereditary gingival fibromatosis and capillary malformation-arteriovenous malformation. Recently, novel gene variants, including RIT1, RRAS, RASA2, A2ML1, SOS2 and LZTR1, have been shown to be associated with RASopathies, further expanding the disease entity. Although further analysis will be needed, these findings will help to better elucidate an understanding of the pathogenesis of these disorders and will aid in the development of potential therapeutic approaches. In this review, we summarize the novel genes that have been reported to be associated with RASopathies and highlight the cardiovascular abnormalities that may arise in affected individuals.

Oxidative stress in aging human skin

Oxidative stress in skin plays a major role in the aging process. This is true for intrinsic aging and even more for extrinsic aging. Although the results are quite different in dermis and epidermis, extrinsic aging is driven to a large extent by oxidative stress caused by UV irradiation. In this review the overall effects of oxidative stress are discussed as well as the sources of ROS including the mitochondrial ETC, peroxisomal and ER localized proteins, the Fenton reaction, and such enzymes as cyclooxygenases, lipoxygenases, xanthine oxidases, and NADPH oxidases. Furthermore, the defense mechanisms against oxidative stress ranging from enzymes like superoxide dismutases, catalases, peroxiredoxins, and GSH peroxidases to organic compounds such as L-ascorbate, α-tocopherol, beta-carotene, uric acid, CoQ10, and glutathione are described in more detail. In addition the oxidative stress induced modifications caused to proteins, lipids and DNA are discussed. Finally age-related changes of the skin are also a topic of this review. They include a disruption of the epidermal calcium gradient in old skin with an accompanying change in the composition of the cornified envelope. This modified cornified envelope also leads to an altered anti-oxidative capacity and a reduced barrier function of the epidermis.

Skin aging, gene expression and calcium

The human epidermis provides a very effective barrier function against chemical, physical and microbial insults from the environment. This is only possible as the epidermis renews itself constantly. Stem cells located at the basal lamina which forms the dermoepidermal junction provide an almost inexhaustible source of keratinocytes which differentiate and die during their journey to the surface where they are shed off as scales. Despite the continuous renewal of the epidermis it nevertheless succumbs to aging as the turnover rate of the keratinocytes is slowing down dramatically. Aging is associated with such hallmarks as thinning of the epidermis, elastosis, loss of melanocytes associated with an increased paleness and lucency of the skin and a decreased barrier function. As the differentiation of keratinocytes is strictly calcium dependent, calcium also plays an important role in the aging epidermis. Just recently it was shown that the epidermal calcium gradient in the skin that facilitates the proliferation of keratinocytes in the stratum basale and enables differentiation in the stratum granulosum is lost in the process of skin aging. In the course of this review we try to explain how this calcium gradient is built up on the one hand and is lost during aging on the other hand. How this disturbed calcium homeostasis is affecting the gene expression in aged skin and is leading to dramatic changes in the composition of the cornified envelope will also be discussed. This loss of the epidermal calcium gradient is not only specific for skin aging but can also be found in skin diseases such as Darier disease, Hailey-Hailey disease, psoriasis and atopic dermatitis, which might be very helpful to get a deeper insight in skin aging.

Laboratory diagnosis of paraneoplastic pemphigus

BACKGROUND

Paraneoplastic pemphigus (PNP) is a multiorgan disease characterized by antibodies against plakins, desmogleins and the α2-macroglobulin-like-1 (A2ML1) protein, in association with an underlying neoplasm. Accurate diagnosis relies on the demonstration of these autoantibodies in serum.

OBJECTIVES

To evaluate the value of different laboratory techniques in the serological diagnosis of PNP.

METHODS

We performed immunoblotting, envoplakin (EP) enzyme-linked immunosorbent assay (ELISA), indirect immunofluorescence (IIF) on rat bladder, radioactive immunoprecipitation and a nonradioactive combined immunoprecipitation-immunoblot assay. Additional assays included BP180 ELISA and BP230 ELISA. We included the sera of 19 patients with PNP and 40 control subjects.

RESULTS

The sensitivities were 63% for anti-EP ELISA, 74% for rat bladder IIF, 89% for immunoblotting, 95% for radioactive immunoprecipitation and 100% for nonradioactive immunoprecipitation. Specificities ranged from 86% to 100%. The BP180 and BP230 ELISAs had low sensitivity and specificity for PNP. The combination of rat bladder IIF and immunoblot showed 100% sensitivity and specificity. The analysis of sequential PNP sera showed that antibody titres may decrease over time, possibly resulting in negative outcomes for EP ELISA and rat bladder IIF studies.

CONCLUSIONS

The detection of autoantibodies against EP and periplakin, or A2ML1 by immunoprecipitation is most sensitive for PNP. The combination of rat bladder IIF and immunoblotting is equally sensitive and highly specific, and represents an alternative valuable and relatively easy approach for the serological diagnosis of PNP.

Heterozygous germline mutations in A2ML1 are associated with a disorder clinically related to Noonan syndrome

Noonan syndrome (NS) is a developmental disorder characterized by short stature, facial dysmorphisms and congenital heart defects. To date, all mutations known to cause NS are dominant, activating mutations in signal transducers of the RAS/mitogen-activated protein kinase (MAPK) pathway. In 25% of cases, however, the genetic cause of NS remains elusive, suggesting that factors other than those involved in the canonical RAS/MAPK pathway may also have a role. Here, we used family-based whole exome sequencing of a case-parent trio and identified a de novo mutation, p.(Arg802His), in A2ML1, which encodes the secreted protease inhibitor α-2-macroglobulin (A2M)-like-1. Subsequent resequencing of A2ML1 in 155 cases with a clinical diagnosis of NS led to the identification of additional mutations in two families, p.(Arg802Leu) and p.(Arg592Leu). Functional characterization of these human A2ML1 mutations in zebrafish showed NS-like developmental defects, including a broad head, blunted face and cardiac malformations. Using the crystal structure of A2M, which is highly homologous to A2ML1, we identified the intramolecular interaction partner of p.Arg802. Mutation of this residue, p.Glu906, induced similar developmental defects in zebrafish, strengthening our conclusion that mutations in A2ML1 cause a disorder clinically related to NS. This is the first report of the involvement of an extracellular factor in a disorder clinically related to RASopathies, providing potential new leads for better understanding of the molecular basis of this family of developmental diseases.

α-2-Macroglobulin: a physiological guardian

Alpha macroglobulins are large glycoproteins which are present in the body fluids of both invertebrates and vertebrates. Alpha-2-macroglobulin (α2 M), a key member of alpha macroglobulin superfamily, is a high-molecular weight homotetrameric glycoprotein. α2 M has many diversified and complex functions, but it is primarily known by its ability to inhibit a broad spectrum of proteases without the direct blockage of the protease active site. α2 M is also known to be involved in the regulation, transport, and a host of other functions. For example, apart from inhibiting proteinases, it regulates binding of transferrin to its surface receptor, binds defensin and myelin basic protein, etc., binds several important cytokines, including basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF), nerve growth factor (NGF), interleukin-1β (IL-1β), and interleukin-6 (IL-6), and modify their biological activity. α2 M also binds a number of hormones and regulates their activity. α2 M is said to protect the body against various infections, and hence, can be used as a biomarker for the diagnosis and prognosis of a number of diseases. However, this multipurpose antiproteinse is not "fail safe" and could be damaged by reactive species generated endogenously or exogenously, leading to various pathophysiological conditions.

Identifying host pathogenic pathways in bovine digital dermatitis by RNA-Seq analysis

Digital dermatitis is a painful foot disease compromising welfare in dairy cattle. The disease has a complex multibacterial aetiology, but little is known about its pathogenesis. In this study, gene expression in skin biopsies from five bovine digital dermatitis lesions and five healthy bovine feet was compared using RNA-Seq technology. Differential gene expression was determined after mapping transcripts to the Btau 4.0 genome. Pathway analysis identified gene networks involving differentially expressed transcripts. Bovine digital dermatitis lesions had increased expression of mRNA for α2-macroglobulin-like 1, a protein potentially involved in bacterial immune evasion and bacterial survival. There was increased expression of keratin 6A and interleukin 1β mRNA in bovine digital dermatitis lesions, but reduced expression of most other keratin and keratin-associated genes. There was little evidence of local immune reactions to the bacterial infection present in lesions.

Anti-α-2-macroglobulin-like-1 autoantibodies are detected frequently and may be pathogenic in paraneoplastic pemphigus

Paraneoplastic pemphigus (PNP) shows autoantibodies mainly to plakin and desmosomal cadherin family proteins. We have recently identified alpha-2-macroglobulin-like-1 (A2ML1), a broad range protease inhibitor, as a unique PNP antigen. In this study, we tested a large number of PNP sera by various methods. Forty (69.0%) of 58 PNP sera recognized A2ML1 recombinant protein expressed in COS7 cells by immunofluorescence (IF) and/or immunoprecipitation (IP)/immunoblotting (IB). IP/IB showed higher sensitivity than IF. In addition, 22 (37.9%) PNP sera reacted with A2ML1 by IB of cultured normal human keratinocytes (NHKs) under non-reducing conditions. Statistical analyses using various clinical and immunological data showed that the presence of anti-A2ML1 autoantibodies was associated with early disease onset and absence of ocular lesions. Next, to investigate the pathogenic role of anti-A2ML1 antibody, we performed additional functional studies. Addition of anti-A2ML1 polyclonal antibody to culture media decreased NHK cell adhesion examined by dissociation assay, and increased plasmin activity detected by casein zymography, suggesting that anti-A2ML1 antibody may decrease NHK cell adhesion through plasmin activation by inhibition of A2ML1. This study demonstrates that autoantibodies to A2ML1 are frequently and specifically detected and may have a pathogenic role in PNP.

Cloning, distribution and primary immune characteristics of amphioxus alpha-2 macroglobulin

Alpha-2 macroglobulin (α(2)M), a broad-spectrum protease inhibitor, exists widely in vertebrates and invertebrates, but little information is available to date regarding α(2)M in amphioxus, an animal bridging from invertebrates to vertebrates. Here we first show that the full α(2)M cDNA of Branchiostoma japonicum (Bjα(2)m) contained 5545 bp with an open reading frame of 4593 bp encoding signal sequence of 16 amino acid residues and a mature protein of 1514 residues. The calculated molecular mass and pI of mature Bjα(2)M were 164.2 kDa and 4.6 respectively. Bjα(2)m was mainly expressed in the hepatic caecum and hind-gut in a tissue-specific manner, contrasting to the primary expression of α(2)M in vertebrate liver. Following challenge with lipopolysaccharide (LPS), Bjα(2)m expression was significantly up-regulated (7-folds) at 8 h and then declined to the base line at 16 h. Taken together, it is suggested that Bjα(2)M is an immune-relevant molecule possibly involved in the acute phase response via the digestive organs.

Hornerin is a component of the epidermal cornified cell envelopes

A single-nucleotide polymorphism within the gene encoding hornerin (HRNR) has recently been linked with atopic dermatitis (AD) susceptibility. HRNR shares features with filaggrin, a key protein for keratinocyte differentiation, but conflicting reports have been published concerning its expression in the epidermis, and its role is still unknown. To analyze HRNR expression and function in the epidermis, anti-HRNR antibodies were produced and used in Western blot analysis and immunohistochemical, confocal, and immunoelectron microscopy analyses of human skin and of cornified cell envelopes purified from plantar stratum corneum. We also tested whether HRNR was a substrate of transglutaminases. In the epidermis, HRNR was detected at the periphery of keratohyalin granules in the upper granular layer and at the corneocyte periphery in the whole cornified layer. Detected in Western blot analysis as numerous bands, HRNR was relatively insoluble and only extracted from epidermis with urea and/or reducing agents. The presence of HRNR in the purified envelopes was confirmed by immunoelectron microscopy and by Western blot analysis after V8-protease digestion. HRNR was shown to be a substrate of transglutaminase 3. These data demonstrate that HRNR is a component of cornified cell envelopes of human epidermis. Its reduced expression in AD may contribute to the epidermal barrier defect observed in the disease.