Editing the genome of Aphanomyces invadans using CRISPR/Cas9

Background

The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system is increasingly being used for genome editing experiments. It is a system to add, delete and/or replace parts of a gene in situ in a time- and cost-efficient manner. The genome of many organisms has been edited using this system. We tested the CRISPR/Cas9 system in Aphanomyces invadans, an oomycete, which is the causative agent of epizootic ulcerative syndrome (EUS) in many fish species. Extracellular proteases produced by this oomycete are believed to play a role in EUS virulence.

Methods

We designed three single guide-RNAs (gRNA) to target A. invadans serine protease gene. These gRNAs were individually combined with the Cas9 to form ribo-nucleo-protein (RNP) complex. A. invadans protoplasts were then transfected with RNP complexes. After the transfection, the target gene was amplified and subjected to sequencing. Zoospores of A. invadans were also transfected with the RNP complex. Three groups of dwarf gourami (Trichogaster lalius) were then experimentally inoculated with (i) non-treated A. invadans zoospores; (ii) RNP-treated A. invadans zoospores; and (iii) autoclaved pond water as negative control, to investigate the effect of edited serine protease gene on the virulence of A. invadans in vivo.

Results

Fluorescence microscopy showed sub-cellular localization of RNP complex in A. invadans protoplasts and zoospores. Sequencing results from the protoplast DNA revealed a point mutation in the target gene. A matching mutation was also detected in zoospores after similar treatment with the same RNP complex. In vivo results showed that the CRISPR/Cas9-treated A. invadans zoospores did not produce EUS clinical signs in the fish. These results were then confirmed by histopathological staining of the muscle sections using Gomori’s methenamine silver nitrate and hematoxylin and eosin stains.

Conclusions

Results obtained in this study indicate that the RNP complex caused effective mutation in the target gene. This hindered the production of serine protease, which ultimately impeded the manifestation of EUS in the fish. Our methods thus establish a promising approach for functional genomics studies in A. invadans and provide novel avenues to develop effective strategies to control this pathogen.

Distribution of Curcumin and THC in Peripheral Blood Mononuclear Cells Isolated from Healthy Individuals and Patients with Chronic Lymphocytic Leukemia

Background/Aim: Curcumin is being widely investigated for its anticancer properties and studies in the literature suggest that curcumin distributes to a higher degree in tumor versus non-tumor cells. In the current study, we report on investigation of the distribution of curcumin and metabolism to THC in PBMC from healthy individuals and chronic lymphocytic leukemia (CLL) patients following exposure to Lipocurc™ (liposomal curcumin). Materials and Methods: The time and temperature-dependent distribution of liposomal curcumin and metabolism to tetrahydrocurcumin (THC) were measured in vitro in human peripheral blood mononuclear cells (PBMC) obtained from healthy individuals, PBMC_HI(cryopreserved and freshly isolated PBMC) and CLL patients (cryopreserved PBMC) with lymphocyte counts ranging from 17-58×10⁶ cells/ml (PBMC_{CLL,Grp 1}) and >150×10⁶ cells/ml (PBMC_{CLL,Grp 2}). PBMC were incubated in plasma protein supplemented media with Lipocurc™ for 2-16 min at 37°C and 4°C and the cell and medium levels of curcumin determined by LC-MS/MS. Results: PBMC from CLL patients displayed a 2.2-2.6-fold higher distribution of curcumin compared to PBMC_HICurcumin distribution into PBMCCLL, Grp 1/Grp 2 ranged from 384.75 - 574.50 ng/g w.w. of cell pellet and was greater compared to PBMC_HIthat ranged from 122.27-220.59 ng/g w.w. of cell pellet following incubation for up to 15-16 min at 37°C. The distribution of curcumin into PBMC_{CLL,Grp 2} was time-dependent in comparison to PBMC_HIwhich did not display a time-dependence and there was no temperature-dependence for curcumin distribution in either cell type. Curcumin was metabolized to THC in PBMC. The metabolism of curcumin to THC was not markedly different between PBMC_HI(range=23.94-42.04 ng/g w.w. cell pellet) and PBMC_{CLL,Grp 1/Grp 2} (range=23.08-48.22 ng/g. w.w. cell pellet). However, a significantly greater time and temperature-dependence was noted for THC in PBMC_{CLL,Grp 2} compared to PBMC_HIConclusion: Curcumin distribution into PBMC from CLL patients was higher compared to PBMC from healthy individuals, while metabolism to THC was similar. The potential for a greater distribution of curcumin into PBMC from CLL patients may be of therapeutic benefit.

In vitro investigations on extracellular proteins secreted by Aphanomyces invadans, the causative agent of epizootic ulcerative syndrome

BACKGROUND

Proteases produced by many microorganisms, including oomycetes, are crucial for their growth and development. They may also play a critical role in disease manifestation. Epizootic ulcerative syndrome is one of the most destructive fish diseases known. It is caused by the oomycete Aphanomyces invadans and leads to mass mortalities of cultured and wild fish in many countries. The areas of concern are Australia, China, Japan, South and Southeast Asian countries and the USA. Extracellular proteases produced by this oomycete are believed to trigger EUS pathogenesis in fish. To address this activity, we collected the extracellular products (ECP) of A. invadans and identified the secreted proteins using SDS-PAGE and mass spectrometery. A. invadans was cultivated in liquid Glucose-Peptone-Yeats media. The culture media was ultra-filtered through 10 kDa filters and analysed using SDS-PAGE. Three prominent protein bands from the SDS gel were excised and identified by mass spectrometery. Furthermore, we assessed their proteolytic effect on casein and immunoglobulin M (IgM) of rainbow trout (Oncorhynchus mykiss) and giant gourami (Osphronemus goramy). Antiprotease activity of the fish serum was also investigated.

RESULTS

BLASTp analysis revealed that the prominent secreted proteins were proteases, mainly of the serine and cysteine types. Proteins containing fascin-like domain and bromodomain were also identified. We could demonstrate that the secreted proteases showed proteolytic activity against the casein and the IgM of both fish species. The anti-protease activity experiment showed that the percent inhibition of the common carp serum was 94.2% while that of rainbow trout and giant gourami serum was 7.7 and 12.9%, respectively.

CONCLUSIONS

The identified proteases, especially serine proteases, could be the potential virulence factors in A. invadans and, hence, are candidates for further functional and host-pathogen interaction studies. The role of identified structural proteins in A. invadans also needs to be investigated further.

Distribution and Metabolism of Lipocurc™ (Liposomal Curcumin) in Dog and Human Blood Cells: Species Selectivity and Pharmacokinetic Relevance

BACKGROUND/AIM

The aim of this study was to investigate the distribution of curcumin (in the form of Lipocurc™) and its major metabolite tetrahydrocurcumin (THC) in Beagle dog and human red blood cells, peripheral blood mononuclear cells (PBMC) and hepatocytes.

MATERIALS AND METHODS

Lipocurc™ was used as the source of curcumin for the cell distribution assays. In vitro findings with red blood cells were also compared to in vivo pharmacokinetic data available from preclinical studies in dogs and phase I clinical studies in humans.

RESULTS

High levels of curcumin were measured in PBMCs (625.5 ng/g w.w. cell pellet or 7,297 pg/10⁶ cells in dog and 353.7 ng/g w.w. cell pellet or 6,809 pg/10⁶ cells in human) and in hepatocytes (414.5 ng/g w.w. cell pellet or 14,005 pg/10⁶ cells in dog and 813.5 ng/g w.w. cell pellet or 13,780 pg/10⁶ cells in human). Lower curcumin levels were measured in red blood cells (dog: 78.4 ng/g w.w. cell pellet or 7.2 pg/10⁶ cells, human: 201.5 ng/g w.w. cell pellet or 18.6 pg/10⁶ cells). A decrease in the medium concentration of curcumin was observed in red blood cells and hepatocytes, but not in PBMCs. Red blood cell levels of THC were ~5-fold higher in dog compared to human and similar between dog and human for hepatocytes and PBMCs. The ratio of THC to curcumin found in the red blood cell medium following incubation was 6.3 for dog compared to 0.006 for human, while for PBMCs and hepatocytes the ratio of THC to curcumin in the medium did not display such marked species differences.

CONCLUSION

There was an excellent correlation between the in vitro disposition of curcumin and THC following incubation with red blood cells and in vivo plasma levels of curcumin and THC in dog and human following intravenous infusion. The disposition of curcumin in blood cells is, therefore, species-dependent and of pharmacokinetic relevance.

Angiomyofibroblastoma of Vulva in a Very Young Adult Female: A Rare Case Report

Angiomyofibroblastoma is a rare, well circumscribed benign mesenchymal neoplasm, usually arising in the pelviperineal region, especially the vulva and apparently composed of stromal cells distinctive to this anatomic region. Preoperative diagnosis of Angiomyofibroblastoma is very difficult, mostly diagnosed as Barthloin cyst due to its anatomical location. It is a histological diagnosis. In this article we report a case of Angiomyofibroblastoma of vulva.

Liposomes ameliorate Crizotinib- and Nilotinib-induced inhibition of the cardiac IKr channel and QTc prolongation

Crizotinib (Xalkori®) and nilotinib (Tasigna®) are tyrosine kinase inhibitors approved for the treatment of non-small cell lung cancer and chronic myeloid leukemia, respectively. Both have been shown to result in electrocardiogram rate-corrected Q-wave T-wave interval (QTc) prolongation in humans and animals. Liposomes have been shown to ameliorate drug-induced effects on the cardiac-delayed rectifier K(+) current (IKr, KV11.1), coded by the human ether-a-go-go-related gene (hERG). This study was undertaken to determine if liposomes would also decrease the effect of crizotinib and nilotinib on the IKr channel. Crizotinib and nilotinib were tested in an in vitro IKr assay using human embryonic kidney (HEK) 293 cells stably transfected with the hERG. Dose-responses were determined and the 50% inhibitory concentrations (IC50s) were calculated. When the HEK 293 cells were treated with crizotinib or nilotinib that were mixed with liposomes, there was a significant decrease in the IKr channel inhibitory effects of these two drugs. When isolated, rabbit hearts were exposed to crizotinib or nilotinib, there were significant increases in QTc prolongation. Mixing either of the drugs with liposomes ameliorated the effects of the drugs. Rabbits dosed intravenously (IV) with crizotinib or nilotinib showed QTc prolongation. When liposomes were injected prior to crizotinib or nilotinib, the liposomes decreased the effects on the QTc interval. The use of liposomal encapsulated QT-prolongation agents, or giving liposomes in combination with drugs, may decrease their cardiac liability.

Road traffic injuries in Rawalpindi city, Pakistan

Data on road traffic accident (RTA) injuries and their outcome are scarce in Pakistan. This study assessed patterns of RTA injuries reported in Rawalpindi city using standard surveillance methods. All RTA injury patients presenting to emergency departments of 3 tertiary care facilities from July 2007 to June 2008 were included. RTA injuries (n = 19 828) accounted for 31.7% of all injuries. Among children aged 0-14 years females suffered twice as many RTA injuries as males (21.3% versus 11.4%), whereas this trend reversed for the age group 15-24 years (41.9% versus 21.7%). One-fifth of injuries were either fractures or concussion. Severity and outcome of injuries were worse for the age group 45 years and older. For every road traffic death in Rawalpindi city, 29 more people were hospitalized and 177 more received emergency department care. These results suggest the need for better RTA injury surveillance to identify preventive and control measures for the increasingly high road disease burden in this city.

Sebaceous lymphadenoma of the parotid gland

Sebaceous differentiation in salivary gland tissue is common. However, sebaceous neoplasms within the salivary glands are rare. We present the case of a sebaceous lymphadenoma with unusual features, arising in the parotid gland of a 60-year-old male. To the best of our knowledge, this is the first report of the ultrasound and MRI characteristics of this rare tumour. The difficulties encountered in reaching a definitive diagnosis both radiologically and histologically are described.

Relationship between serum hyaluronic acid level and disease activity in early rheumatoid arthritis

OBJECTIVES

To measure hyaluronic acid (HA) levels, which are raised in active rheumatoid arthritis (RA), in patients with early RA, and to assess the correlation with clinical and laboratory indices of disease activity and with subsequent radiographic erosive status.

PATIENTS AND METHODS

Patients fulfilling ACR criteria were recruited into a prospective cohort within 6 months of disease onset and reviewed every 6 months. An HA binding protein based sandwich ELISA was used to measure HA in 240 sera from 82 patients at regular intervals.

RESULTS

Patients had higher HA levels than age matched healthy blood donor controls (median 37.4 v 29.1 ng/ml, respectively, p<0.02), which increased with more prolonged disease. Baseline HA level correlated with measures of disease activity, including swollen and tender joint counts, HAQ, global assessments, ESR, and CRP; was higher in men; and increased with age. There was no relationship with HLA-DRB1 shared epitope or rheumatoid factor status. At 6 and 12 month follow up visits, HA levels were higher in patients who later developed erosions. However, a raised HA level was not a good predictor of erosions.

CONCLUSIONS

Serum HA level correlates with clinical and laboratory measures of disease activity in early RA, but is unlikely to be of practical use in clinical practice.

Pancreatic pseudocyst in paediatric systemic lupus erythematosus

Pancreatitis is a rare complication of paediatric systemic lupus erythematosus (SLE). We describe a child with severe form of SLE who initially developed acute pancreatitis, subsequently complicated by extensive pancreatic pseudocyst. The treatment and outcome are discussed.

Role of Src kinases and Syk in Fcgamma receptor-mediated phagocytosis and phagosome-lysosome fusion

Phagocytosis is increased by Fcgamma receptors (FcgammaRs), and studies with syk(-/-) macrophages demonstrated that Syk kinase is required for FcgammaR phagocytosis. Similar studies with macrophages lacking the Src family kinases Hck, Fgr, and Lyn showed that these kinases are not required for phagocytosis but that they enhance the rate of particle engulfment. In this report we show that both wild-type and hck(-/-)fgr(-/-) macrophages expressed Fyn, Src, and Yes and that these kinases were activated on ingestion of immunoglobulin G (IgG)-coated particles and redistributed, together with Syk, to actin-rich phagocytic cups and the phagosomal membrane. At doses blocking IgG-dependent phagocytosis, the tyrosine kinase inhibitors PP1 and piceatannol inhibited both Src family kinase and Syk activities, as well as their redistribution to actin-rich phagocytic cups. Hck, Fgr, and Lyn were dispensable for lysosome-phagosome fusion (PLF) induced by IgG-coated particles. However, PP1 or piceatannol hampered unopsonized yeast-induced PLF despite the fact that they did not block yeast internalization.

Chemokines trigger immediate beta2 integrin affinity and mobility changes: differential regulation and roles in lymphocyte arrest under flow

Chemokines trigger rapid integrin-dependent lymphocyte arrest to vascular endothelium. We show that the chemokines SLC, ELC, and SDF-1alpha rapidly induce lateral mobility and transient increase of affinity of the beta2 integrin LFA-1. Inhibition of phosphatidylinositol 3-OH kinase (PI(3)K) activity blocks mobility but not affinity changes and prevents lymphocyte adhesion to ICAM-1 immobilized at low but not high densities, suggesting that mobility enhances the frequency of encounters between high-affinity integrin and ligand but that at higher ligand density affinity changes are sufficient for arrest. Thus, chemokines trigger, through distinct signaling pathways, both a high-affinity state and lateral mobility of LFA-1 that can coordinately determine the vascular arrest of circulating lymphocytes under physiologic conditions.

Coexistent linear scleroderma and juvenile systemic lupus erythematosus

We describe a girl who initially presented with linear scleroderma. Five and a half years later she developed systemic lupus erythematosus (SLE). Previous descriptions of the coexistence of linear scleroderma and SLE in childhood are reviewed.

New form of idiopathic osteolysis: nodulosis, arthropathy and osteolysis (NAO) syndrome

We describe 10 patients (6 females and 4 males) from 6 unrelated families with an autosomal recessive disease characterized by simultaneous presentation of nodulosis, arthropathy and osteolysis. They were followed up regularly at King Faisal Specialist Hospital and Research Center in Saudi Arabia for clinical evaluation, serial blood work-up, and evaluating radiological changes. Nodulosis and arthropathy were the clinical criteria for inclusion in this study, and the ten patients fulfilled these criteria. All patients had nodulosis and distal arthropathy. Eight patients (80%) presented with deformed hands and four (40%) with painful hands. All patients had parents who were first cousins and three families had more than one affected child, the finding suggesting autosomal recessive inheritance. Osteopenia and undertubulation of bones distally more than proximally, and upper limbs affected more often than lower limbs, were found in all patients. Osteolysis was seen in carpal and tarsal bones. Other common findings were sclerotic cranial sutures, brachycephaly, and broad medial clavicles. This novel phenotype should be considered in the differential diagnosis of chronic arthritis. Familial arthropathies are more often seen in communities where interfamilial marriage is common. Such a collection of patients is ideal for homozygosity mapping of the disease locus.

Activation of cAMP-dependent protein kinase is necessary for actin rearrangements in human neutrophils during phagocytosis

We have investigated the role of cAMP and cAMP-dependent protein kinase (cAPK) in neutrophil phagocytosis. Inhibition of cAPK with H-89 reduced complement- and IgG-dependent phagocytosis to 83 and 46%, respectively. Fluorescence intensity measurements of phalloidin-stained actin in neutrophils showed a reduced amount of filamentous actin (F-actin) in pseudopods and around the phagosome in cells treated with H-89 or cAMP-elevating agents (forskolin and rolipram). The amount of phosphotyrosine-containing proteins was also reduced in pseudopods and around the phagosome. Taken together, the data show that cAMP/cAPK regulates F-actin reorganization during receptor-mediated phagocytosis, particularly triggered by IgG-FcR interaction. Our results support the hypothesis that active subcortical reorganization of F-actin is a prerequisite for FcR-mediated phagocytosis, but is less important during CR3-mediated ingestion.