Annexin A8 displays unique phospholipid and F-actin binding properties

AbstractAnnexin A8 is a poorly characterized member of the annexin family of Ca2+-regulated membrane binding proteins. Initially only identified at the cDNA level it had been tentatively linked to acute promyelocytic leukaemia (APL) due to its high and regulated expression in APL-derived cells. Here we identify unique properties of the annexin A8 protein. We show that it binds Ca2+-dependently and with high specificity to phosphatidylinositol (4,5)-bisphosphate (PtdIns(4,5)P2) and is also capable of interacting with F-actin. In line with these characteristics annexin A8 is recruited to F-actin-associated PtdIns(4,5)P2-rich membrane domains formed in HeLa cells upon infection with non-invading enteropathogenic Escherichia coli. These properties suggest a role of annexin A8 in the organization of certain actin-associated membrane domains

Active site specificity profiling of the matrix metalloproteinase family: Proteomic identification of 4300 cleavage sites by nine MMPs explored with structural and synthetic peptide cleavage analyses

Secreted and membrane tethered matrix metalloproteinases (MMPs) are key homeostatic proteases regulating the extracellular signaling and structural matrix environment of cells and tissues. For drug targeting of proteases, selectivity for individual molecules is highly desired and can be met by high yield active site specificity profiling. Using the high throughput Proteomic Identification of protease Cleavage Sites (PICS) method to simultaneously profile both the prime and non-prime sides of the cleavage sites of nine human MMPs, we identified more than 4300 cleavages from P6 to P6′ in biologically diverse human peptide libraries. MMP specificity and kinetic efficiency were mainly guided by aliphatic and aromatic residues in P1′ (with a ~ 32–93% preference for leucine depending on the MMP), and basic and small residues in P2′ and P3′, respectively. A wide differential preference for the hallmark P3 proline was found between MMPs ranging from 15 to 46%, yet when combined in the same peptide with the universally preferred P1′ leucine, an unexpected negative cooperativity emerged. This was not observed in previous studies, probably due to the paucity of approaches that profile both the prime and non-prime sides together, and the masking of subsite cooperativity effects by global heat maps and iceLogos. These caveats make it critical to check for these biologically highly important effects by fixing all 20 amino acids one-by-one in the respective subsites and thorough assessing of the inferred specificity logo changes. Indeed an analysis of bona fide MEROPS physiological substrate cleavage data revealed that of the 37 natural substrates with either a P3-Pro or a P1′-Leu only 5 shared both features, confirming the PICS data. Upon probing with several new quenched-fluorescent peptides, rationally designed on our specificity data, the negative cooperativity was explained by reduced non-prime side flexibility constraining accommodation of the rigidifying P3 proline with leucine locked in S1′. Similar negative cooperativity between P3 proline and the novel preference for asparagine in P1 cements our conclusion that non-prime side flexibility greatly impacts MMP binding affinity and cleavage efficiency. Thus, unexpected sequence cooperativity consequences were revealed by PICS that uniquely encompasses both the non-prime and prime sides flanking the proteomic-pinpointed scissile bond

Expression of Connexin 43 in Granular Cell Tumors of the Skin, Tongue and Esophagus

Background: Granular cell tumors (GCT) are rare neoplasms of Schwann cell origin occurring in the skin and in other organs. The etiopathogenesis of GCT is yet poorly understood. Connexin 43 (Cx43) is the most broadly expressed gap junction protein in humans, the tumoral role of which has been investigated in several types of tumors. Its role in GCT of the skin, oral cavity and gastrointestinal tract is as yet unknown. Methods: Herein, we present a study on the immunohistochemical expression of Cx43 in GCT of the skin (n = 15), tongue (n = 4) and esophagus (n = 3). Immunolabeling was scored positive (weak (+), moderate (++) or strong (+++)). Results: Cx43 was expressed by all cases of GCT of the skin, tongue and esophagus (22/22), showing moderate to strong staining. All tissue sections of GCT were characterized by a diffuse, cytoplasmic staining pattern of the tumor cells. None of those showed membranous or nuclear staining. Conclusion: Our results suggest that Cx43 probably plays an important role in the development of this rare tumor entity

Proteolytic cleavage of annexin 1 by human leukocyte elastase

AbstractAnnexin 1 has been shown to participate through its unique N-terminal domain in the recruitment and activation of leukocytes at sites of inflammation. Peptides derived from this domain are true mimetics of the annexin 1 action in all inflammation models tested and most likely serve as the active entities generated at sites of inflammation. To elucidate mechanisms underlying peptide generation we used isolated blood leukocytes and endothelial cell monolayers. We show that following endothelial adhesion, annexin 1 was externalized from leukocytes and rapidly cleaved. Addition of purified annexin 1 to degranulating leukocytes resulted in the truncation of annexin 1, which seemed to depend on the proteolytic activity of human leukocyte elastase (HLE). The capacity of elastase to proteolytically cleave annexin 1 was confirmed using both purified annexin 1 and HLE. The identification of annexin 1 as a substrate for HLE supports the model in which annexin 1 participates in regulating leukocyte emigration into inflamed tissue through N-terminal peptides generated at inflammatory sites

Aberrant cytoplasmic connexin43 expression as a helpful marker in vascular neoplasms

Background Gap junctions consisting of connexins (Cx) are fundamental in controlling cell proliferation, differentiation, and cell death. Cx43 is the most broadly expressed Cx in humans and is attributed an important role in skin tumor development. Its role in cutaneous vascular neoplasms is yet unknown. Methods Fifteen cases each of cutaneous angiosarcoma (cAS), Kaposi sarcoma (KS), and cherry hemangioma (CH) were assessed by immunohistochemistry for expression of Cx43. Expression pattern, intensity, and percentage of positively stained cells were analyzed. Solid basal cell carcinomas served as positive and healthy skin as negative controls. Results Most cases of cAS presented with a strong Cx43 staining of almost all tumor cells, whereas endothelia of KS showed medium expression and CH showed mostly weak expression. In comparison with KS or cAS, the staining intensity of CH was significantly lower (P ≤ 0.001). All tissue sections of both cAS and KS were characterized by a mostly diffuse, cytoplasmic staining pattern of the vascular endothelia. None of those showed nuclear staining. Conclusion The high-to-intermediate expression of Cx43 observed in all cases of cAS and KS suggests that this Cx may play a role in the development of malignant vascular neoplasms and serve as a helpful diagnostic marker

Economic analysis of the costs associated with Hidradenitis suppurativa at a German University Hospital

Background and objectives Hidradenitis suppurativa (HS) significantly affects the patient`s quality of life and leads to multiple medical consultations. Aim of this study was to assess the utilization of medical care of HS patients. Patients and methods All patients presenting in 2017 for an outpatient, day patient and / or inpatient treatment with leading claim type HS at the Department of Dermatology, University Hospital Würzburg, were included. Primary outcome was the economic burden of HS patients, measured by resource utilization in €. Results The largest share of the direct medical costs for HS were the inpatient costs with a leading surgical diagnosis-related group (DRG). Antiseptics were the predominant topical prescription. While doxycycline was the most frequently prescribed systemic therapy, adalimumab was the main cost driver. The difference between in-patient (€ 110.25) and outpatient (€ 26.34) direct non-medical costs was statistically significant (p < 0.001). With regards to indirect medical costs, a statistically significantly higher loss of gross value added (inpatient mean € 1,827.00; outpatient mean € 203.00) and loss of production (inpatient mean € 1,026.00; outpatient mean € 228.00) could be noted (p < 0.001), respectively. Conclusions The present study on disease-specific costs of HS confirms that the hospital care of patients with this disease is cost-intensive. However, the primary goal of physicians is not and should not be to save costs regarding their patients`treatment, but rather the premise to utilize the existing resources as efficient as possible. Reducing the use of costly therapeutics and inpatient stays therefore requires more effective therapy options with an improved cost-benefit profile

Non-alcoholic fatty liver disease and psoriasis - is there a shared proinflammatory network?

Psoriasis is an immune-mediated systemic inflammatory disease that is not limited to the skin but may be associated with arthritis, cardiovascular diseases, metabolic syndrome including diabetes and obesity and, as identified more recently, non-alcoholic fatty liver disease (NAFLD) that occurs in approximately 50 % of all patients with psoriasis. NAFLD is characterized by accumulation of fat in hepatocytes in the absence of excessive alcohol consumption. Over the last two decades, NAFLD has developed to the most common chronic liver disease with an estimated prevalence of 25 % in the Western population. NAFLD ranges from non-inflammatory or bland hepatic steatosis to inflammation of hepatic tissue (non-alcoholic steatohepatitis, NASH) and consecutive liver fibrosis. It is controversial whether the underlying systemic inflammation of psoriasis is contributing to development of NAFLD or if comorbid diseases such as obesity enhance NAFLD development. Recent findings indicate that cytokine-mediated inflammation through TNFα, interleukin (IL)-6 and IL-17 might be the common link between psoriasis and NAFLD. Considering the shared inflammatory pathways, IL-17 pharmacological blockade, which is already well-established for psoriasis, may be a promising strategy to treat both psoriasis and NAFLD. Therefore, early detection of NAFLD and a better understanding of its pathophysiology in the context of the systemic inflammation in psoriasis is important with regard to individualized treatment approaches

EBER in situ hybridization in subcutaneous aluminum granulomas/lymphoid hyperplasia: A diagnostic clue to differentiate injection-associated lymphoid hyperplasia from other forms of pseudolymphomas and cutaneous lymphomas

Background Subcutaneous vaccination or desensitization may induce persistent nodules at the injection sites. Without the knowledge of prior injection, histopathological work-up may be challenging. Objective Aim of this study was to contribute to the histopathological work-up of unclear subcutaneous nodules, especially their differentiation from cutaneous lymphoma. Methods We retrospectively reviewed clinical data and histopathological slides of four patients with subcutaneous nodules, which were suspected to suffer from cutaneous T- or B-cell lymphoma. Sections of these cases and 12 negative controls were stained with hematoxylin and eosin and a standardized immunohistochemical panel of B- and T-cell markers including EBER in situ hybridization as well as electron microscopy. Results In all cases, large histiocytes with granular cytoplasm compatible with intracellular aluminum hydroxide were present. EBER in situ hybridization revealed positive staining of these granular histiocytes while staining was absent in negative controls. Limitations Post hoc completion of medical history revealed that vaccination or specific immunotherapy had been applied before at the biopsy site in only three out of four patients; one patient was lost to follow-up. Conclusion EBER in situ hybridization is an adjunctive tool to differentiate aluminum-induced granuloma/lymphoid hyperplasia from other forms of pseudolymphoma and cutaneous B- or T-cell lymphomas