Modulation of infectious Salmon Anaemia virus infection by clathrin-mediated endocytosis and macropinocytosis inhibitors

Infectious salmon anaemia virus (ISAV) is a pathogen that causes disease and large mortality in farm-raised Salmo salar L., being considered as a major problem in the salmon industry. However, despite its relevance, there are still numerous knowledge gaps on virus entry and early stages of infection. Previous studies suggested that virus entry into cells occurs via endocytosis, with no description of specific mechanisms. However, it remains unknown if the endocytosis induced by ISAV is a clathrin-dependent or clathrin-independent process. This study aimed to identify cellular mechanisms allowing ISAV entry into Atlantic Salmon head kidney (ASK) cells. Our results showed that ISAV can be found in coated pits and membrane ruffles, the latter being induced by a rearrangement of actin filaments promoted by ISAV infection. Additionally, it was determined that ISAV stimulate the uptake of extracellular fluid in a multiplicity of infection (MOI)-dependent manner. When the clathrin-mediated endocytic pathway was pharmacologically inhibited, ISAV infection was significantly reduced but not entirely inhibited. Similarly, when the Na+/H+ exchanger (NHE), a key component of macropinocytosis, was inhibited, ISAV infection was negatively affected. Our results suggest that ISAV enters cells via both clathrin-mediated endocytosis and most likely macropinocytosis.

Chorionic bump: Progression to a subamniotic hematoma

INTRODUCTION

A chorionic bump is an increasingly recognized ultrasound finding in first-trimester scans, which has been associated with early pregnancy loss. In ongoing second-trimester pregnancies, however, chorionic bumps usually resolve over time with no deleterious effect on the fetus. In this report, we describe the incidental ultrasound detection of a chorionic bump in early pregnancy and its progression to a subamniotic hematoma in the second trimester of pregnancy that persisted as such until delivery.

CASE REPORT

A round, echogenic mass protruding from the choriodecidual surface measuring 13 × 11 × 8 mm was first identified during a transvaginal scan at 6.3 weeks' gestation. Subsequent follow-up scan at 8.3 weeks revealed an increase in the size of the chorionic bump to 25 × 20 × 19 mm, which remained stable as determined by the routine late first-trimester scan. At the second-trimester scan, a subamniotic hematoma was identified in the surface of the placenta, close to the insertion of the umbilical cord. Subsequently, the pregnancy proceeded uneventfully.

DISCUSSION

The etiopathology and clinical significance of a chorionic bump remain unclear. The case herein reported demonstrates that a chorionic bump can grow considerably without having a deleterious effect on the early embryo and, occasionally, can persist throughout pregnancy as a subamniotic hematoma.

CONCLUSION

A chorionic bump can occasionally progress to a subamniotic hematoma from the second trimester onwards. This observation further supports the hypothesis that a chorionic bump is the result of choriodecidual bleeding. An alternative explanation for the development of subamniotic hematomas is proposed.

Rapid sequence modification in the highly polymorphic region (HPR) of the hemagglutinin gene of the infectious salmon anaemia virus (ISAV) suggests intra-segmental template switching recombination

The ISAV has a genome composed of eight segments of (-)ssRNA, segment 6 codes for the hemagglutinin-esterase protein, and has the most variable region of the genome, the highly polymorphic region (HPR), which is unique among orthomyxoviruses. The HPR has been associated with virulence, infectivity and pathogenicity. The full length of the HPR is called HPR0 and the strain with this HPR is avirulent, in contrast to strains with deleted HPR that are virulent to varying degrees. The molecular mechanism that gives rise to the different HPRs remains unclear. Here, we studied in vitro the evolution of reassortant recombinant ISAV (rISAV) in Atlantic salmon head kidney (ASK) cells. To this end, we rescued and cultivated a set of rISAV with different segment 6-HPR genotypes using a reverse genetics system and then sequencing HPR regions of the viruses. Our results show rapid multiple recombination events in ISAV, with sequence insertions and deletions in the HPR, indicating a dynamic process. Inserted sequences can be found in four segments of the ISAV genome (segments 1, 5, 6, and 8). The results suggest intra-segmental heterologous recombination, probably by class I and class II template switching, similar to the proposed segment 5 recombination mechanism.

Abstract P4-03-09: Malignant hyperechoic lesions in breast ultrasound - Frequency and characteristics

PURPOSE

Challenge current axiom regarding hyperechogenic lesions in breast US categorized as mainly benign lesions. 2) Present frequency of malignant hyperechoic lesions, describe their sonographic and histological characteristics.

METHOD AND MATERIALS

IRB approved retrospective review of 2369 consecutive US-guided Core biopsies between 2006 and 2014. Lesions were considered hyperechogenic when more than 90% of its volume had higher echogenicity than surrounding subcutaneous tissue. Variables assessed were: age, size, histology, mass or non-mass, margins, echogenicity, acoustic effect, orientation, location, presence of a hypoechoic center, vascularization and BI-RADS category. Qualitative variables were described by percentage distribution, mean and SD.

RESULTS

Thirty one (1,3%) lesions biopsied were hyperechoic: only 17 (54.8%) were benign. We found 14 patients (range, 39-81 years, mean 57,5 years) with hyperechoic cancers, accounting for 1,77% of all cancers. 12 (85,7%) were ductal and 2 (14,3%) lobular histology (mean 17,5 mm range 8-40mm). All of them exhibited a small central hypoechoic area and were partially or completely surrounded by fatty tissue. Shape, margins, orientation and vascular architecture were highly suggestive of malignancy at US, mammography and in MRI (BI-RADS 4B and 5). On histology, all lesions were surrounded by fatty tissue, with a low–cell count collagenous center with a higher peripheral cellularity, mixing and interweaving with adipose tissue.

CONCLUSION

Hyperechogenic breast cancers are rare (1.77%), and we challenge the current concept of high rate of benignity with a 45,2% of chances for malignancy. We propose that hyperechogenicity is given by interweaving bundles with adipose tissue, which provide higher amount of acoustic reflective surfaces, thus explaining its sonographic pattern.

CLINICAL RELEVANCE/APPLICATION

Hyperechogenic breast lesions should not be considered as always benign. Malignancy thresholds should not be influenced by this sonographic characteristic.

We propose histopathological explanation of this sonographic pattern.

Citation Format: Camacho J, Horvath E, Pizzolon MF, Pinochet MA, Gallegos M, Galleguillos C, Uchida M, Cadiz F, Silva C. Malignant hyperechoic lesions in breast ultrasound - Frequency and characteristics. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-03-09.

Association between MMP1 and MMP9 activities and ICAM1 cleavage induced by tumor necrosis factor in stromal cell cultures from eutopic endometria of women with endometriosis

Endometriosis is a benign gynecological pathology in which immune system deregulation may play a role in its initiation and progression. In endometriotic lesions, intercellular adhesion molecule-1 (ICAM1) is released from the cell membrane by proteolytic cleavage of its extracellular domain, a process that coincides with increased expression and proteolytic activity of metalloproteinases such as MMP1 and MMP9. The objective of our study was to investigate the association between MMP1 and MMP9 activities and ICAM1 cleavage mediated by tumor necrosis factor (TNF) in eutopic endometrial stromal cells from women with and without (control) endometriosis during culture. The RNA was evaluated by RT-PCR, and the protein was determined by western blot (ICAM1, MMP1), casein or gelatin zymographies (secreted active MMP1 or MMP9 respectively), ELISA (soluble ICAM1 (sICAM1)), and fluorescence assay (secreted active MMP1). Under basal conditions, proMMP9 dimer and MMP9 were higher in endometriosis cell cultures. In stromal cultures derived from control women and those with endometriosis, TNF augmented the intracellular proMMP1 (1.2-fold in control stromal cells) and ICAM1 (1.4- and 1.9-fold), greatly increased MMP1 and proMMP9 levels, and the sICAM1 concentration (2.3- and 4.3-fold) in their media compared with basal levels. The combination of TNF and MMP9 increased the sICAM1 concentration 14-fold in the endometriosis cell media, whereas GM6001 inhibited the stimulatory effect of TNF in both cell cultures. The deregulation of MMP9, and the TNF participation in the MMP1 and proMMP9 secretions, in the MMP9 expression and in the expression and cleavage of ICAM1 may contribute to the pathophysiology of this disease.

Growth promoting effect of two Sinorhizobium meliloti strains (a wild type and its genetically modified derivative) on a non-legume plant species in specific interaction with two arbuscular mycorrhizal fungi

In the present study, we have investigated whether the ubiquitous rhizosphere soil organism Sinorhizobium meliloti has a plant growth promoting (PGP) effect on non-leguminous plant species. Such PGP activity was investigated for both a wild type strain and its genetically modified (GM) derivative, which had an enhanced biofertilizer capability. The PGP effect of these rhizobial strains was tested in interaction with two arbuscular-mycorrhizal (AM) fungi: G. mosseae or G. intraradices on lettuce (Lactuca sativa L.) plants. Both rhizobial strains were efficient in increasing lettuce biomass and also induced modifications on root morphology, particularly in mycorrhizal plants; thus these strains behave as plant growth promoting rhizobacteria. In non-mycorrhizal plants, both strains exhibited a similar growth promoting effect on lettuce. However, both rhizobial strains differed in mycorrhizal plants with regard to (i) biomass production, (ii) the length of axis and lateral roots, and (iii) the number of lateral roots formed; effects which were, in turn, affected by the AM fungus involved. Microbial treatments were more effective on root growth and morphology at earlier developmental stages (20 days of plant growth) but, in a later stage (after 40 days), the microbial effects were more relevant at increasing plant biomass. The interaction between the GM rhizobial strain and G. mosseae produced the highest growth promoting effect (476% over control), in spite of the fact that G. intraradices showed a quicker and higher colonization ability than G. mosseae. Microbial interactions inducing PGP effects did not benefit AM colonization nor the succinate dehydrogenase activity in the AM fungal mycelium. Irrespective of the underlying mechanisms, which are being now investigated, the interactions between rhizobial strains, as free-living saprophs, and AM fungi are noteworthy, and depend on the microbial genotype involved.