Hyperunstable matrix proteins in the byssus of Mytilus galloprovincialis

The marine mussel Mytilus galloprovincialis is tethered to rocks in the intertidal zone by a holdfast known as the byssus. Functioning as a shock absorber, the byssus is composed of threads, the primary molecular components of which are collagen-containing proteins (preCOLs) that largely dictate the higher order self-assembly and mechanical properties of byssal threads. The threads contain additional matrix components that separate and perhaps lubricate the collagenous microfibrils during deformation in tension. In this study, the thread matrix proteins (TMPs), a glycine-, tyrosine- and asparagine-rich protein family, were shown to possess unique repeated sequence motifs, significant transcriptional heterogeneity and were distributed throughout the byssal thread. Deamidation was shown to occur at a significant rate in a recombinant TMP and in the byssal thread as a function of time. Furthermore, charge heterogeneity presumably due to deamidation was observed in TMPs extracted from threads. The TMPs were localized to the preCOL-containing secretory granules in the collagen gland of the foot and are assumed to provide a viscoelastic matrix around the collagenous fibers in byssal threads

Giant bent-core mesogens in the thread forming process of marine mussels

In marine mussels (Mytilus), byssal threads are made in minutes from prefabricated smectic polymer liquid crystals by a process resembling reaction injection molding. The mesogens in these arrays are known to be natural block copolymers with rodlike collagen cores. Using atomic force microscopy, it was shown that these collagenous mesogens are bent-core or banana-shaped in a manner that is consistent with and predictable from their amino acid sequence. The overall bend angle in preCOL-NG in Mytilus galloproVincialis is about 130°. The mesogens have a center-to-center separation of approximately 22 nm and a length of 200 nm. It is evident that the smectic structure of the prefabricated mesophases remains largely intact over 1-3 ím distances in the molded fibers and is presumably locked in place during molding by cross-linking. Like the smectic liquid crystals of many synthetic banana mesogens, the collagenous mesogens of the byssal threads exhibit SmC2 symmetry with a characteristic tilt of 24.6°. At about 100 % extension, this tilt is considerably reduced and the globular end domains are no longer visible presumably because they have been unraveled

Antimicrobial resistance and co-selection phenomenon in Listeria spp. recovered from food and food production environments

Antimicrobial resistance (AMR), co-selection phenomenon, and the relationship between reduced susceptibility (RSC) to ciprofloxacin (CIP) and resistance to other antimicrobials in Listeria spp. (n = 103) recovered from food processing environments (FPE) and food were investigated. Resistance of Listeria monocytogenes and other listeriae, respectively, to cefoxitin (FOX; 98% vs. 88%), CIP (7% vs. 4%), clindamycin (CLI; 33% vs. 59%) and tetracycline (6% vs. 8%) was observed, as was RSC to CIP (67% vs. 57%) and CLI (65% vs. 41%). L. monocytogenes also possessed RSC to linezolid (LZD; 6%), rifampicin (2%) and streptomycin (6%), with other listeriae displaying RSC to chloramphenicol (4%). L. monocytogenes serotype 1/2a (90%) isolates were more frequently resistant or possessed RSC to CIP compared to serotype 4b (55%) (p = 0.015). When eight strains were experimentally adapted to high concentrations of CIP, co-selection occurred as MICs to benzalkonium chloride (BAC) increased (n = 5), gentamicin MICs remained the same (n = 6) or increased 2-fold (n = 2), and led to RSC to LZD (n = 1) and resistance to CLI (n = 8). Overall, levels of resistance/RSC to CIP in food chain isolates, particularly 1/2a, are concerning. Further, reduced sensitivity to disparate antimicrobials following CIP exposure highlights the need for increased knowledge of co-selection phenomenon linked with antimicrobial agents

PKCα attenuates jagged-1-mediated notch signaling in ErbB-2-positive breast cancer to reverse trastuzumab resistance

Purpose: Breast cancer is the second leading cause of cancer mortality among women worldwide. The major problem with current treatments is tumor resistance, recurrence, and disease progression. ErbB-2–positive breast tumors are aggressive and frequently become resistant to trastuzumab or lapatinib. We showed previously that Notch-1 is required for trastuzumab resistance in ErbB-2–positive breast cancer.Experimental Design: Here, we sought to elucidate mechanisms by which ErbB-2 attenuates Notch signaling and how this is reversed by trastuzumab or lapatinib.Results: The current study elucidates a novel Notch inhibitory mechanism by which PKCα downstream of ErbB-2 (i) restricts the availability of Jagged-1 at the cell surface to transactivate Notch, (ii) restricts the critical interaction between Jagged-1 and Mindbomb-1, an E3 ligase that is required for Jagged-1 ubiquitinylation and subsequent Notch activation, (iii) reverses trastuzumab resistance in vivo, and (iv) predicts better outcome in women with ErbB-2–positive breast cancer.Conclusions: The clinical impact of these studies is PKCα is potentially a good prognostic marker for low Notch activity and increased trastuzumab sensitivity in ErbB-2–positive breast cancer. Moreover, women with ErbB-2–positive breast tumors expressing high Notch activation and low PKCα expression could be the best candidates for anti-Notch therapy

CD70 Expression in Mature T-Cell Lymphomas

Abstract Introduction Mature T-cell lymphomas (TCLs) represent about 15% of the non-Hodgkin lymphomas in U.S. and are a heterogeneous group of neoplasms. TCLs usually have poor outcomes and are resistant to conventional chemotherapy regimens. Therefore, there is a need for identifying biomarkers that could translate into effective novel treatments. CD70 is the TNF superfamily ligand of CD27 and it is being explored as a potential target in CAR-T therapy against TCLs and other neoplasms. Although CD70 expression has been documented in TCL cell lines, thus providing a potential rationale for its use as a therapeutic target, the expression of CD70 among the most frequent TCL subtypes in patient samples has not been previously evaluated. Methods Patients with de novo and/or relapsed mature TCLs diagnosed between 01/2010 and 06/2020 and with available tissue sections were included in the study. The assessment of CD70 expression was performed by immunohistochemistry (IHC) using a novel proprietary antibody developed by CRISPR Therapeutics. CD70 expression was scored using % of expression, intensity (negative, +1, +2, and +3) and H-score {H-score = [(%positive cells intensity 1+) x 1] + [(%positive cells intensity 2+) x 2] + [(%positive cells intensity 3+) x 3]} in neoplastic cells (Figure 1). Clinicopathologic characteristics were collected retrospectively and included age, sex, staging, biopsy site, WHO pathologic classification, immunophenotype, presence of other malignancies, treatment status, disease progression/relapsed, and follow-up. These characteristics were compared with CD70 expression using ANOVA or non-parametric analysis. Overall-survival (OS) was estimated using Kaplan-Meier method and compared using log-rank. A p< 0.05 was considered statistically significant. Results One hundred thirty-six patient samples representing the major subtypes of the 4 categories of mature TCLs were included [nodal TCLs (n=64; including PTCL Th1, and Th2 subtypes and angioimmunoblastic T cell lymphoma - AITL), extranodal (n=35; including primary intestinal lymphomas), cutaneous (n=24; including mycosis fungoides (MF) with large cell transformation), and leukemic (n=13; including adult T cell leukemia/lymphoma)]. Most patients were male (58.8%), in the 6 th or 7 th decade (47.1%), with advanced stage IV (55.7%), no previous malignancies (69.9%) and previously treated (57.2%); 59 of which (88%) received two or more lines of treatment. The median expression of CD70 was 40% (ranged from 0 to 100%) and the median H-score was 110 (ranged from 0 to 300) and was significantly higher (p= 0.006) in peripheral T-cell lymphoma, NOS, primary cutaneous TCLs (non-mycosis fungoides), and AITL (180, 150, and 150, respectively) (Figure 1). The expression of CD70 was more frequent in nodal and extranodal subtypes (including skin), compared to leukemic TCLs (p= 0.005). The expression of CD70 was associated with advanced age at the diagnosis (p= 0.003), CD2 expression (p= 0.01), CD3 expression (p= 0.001), CD16 negativity (p= 0.03), and absence of ALK-1 expression (p= 0.005). After a median follow-up of 19 months (range: 1 - 300 months), 42% of the patients died of disease. The median OS was 76 months (CI95, 38.5 - 113.4 months) and it was not associated with CD70 expression. Conclusions CD70 was highly expressed in most mature TCLs and it was negative in most ALK-positive ALCL. Its expression was associated with nodal and extranodal subtypes, advanced age, expression of CD2, CD3, and negativity for CD16. Therefore, CD70 can be used as a potential biomarker and a target in clinical trials of patients with mature TCLs. Figure 1 Figure 1. Disclosures Iyer: CRISPRX: Research Funding; Seattle Genetics: Research Funding; Rhizen: Research Funding; Merck: Research Funding; Legend: Research Funding; Innate: Research Funding; Spectrum: Research Funding; Trillium: Research Funding; Astra Zeneca: Research Funding; Yingli: Research Funding; Cyclacel: Research Funding. Sagert: CRISPR Therapeutics: Current Employment. Pham: CRISPR Therapeutics: Current Employment. Tipton: CRISPR Therapeutics: Current Employment. Vega: i3Health, Elsevier, America Registry of Pathology, Congressionally Directed Medical Research Program, and the Society of Hematology Oncology: Research Funding; CRISPR Therapeutics and Geron: Research Funding