A novel cell-permeable peptide prevents protein SUMOylation and supports the mislocalization and aggregation of TDP-43

SUMOylation is a post-translational modification (PTM) that exerts a regulatory role in different cellular processes, including protein localization, aggregation, and biological activities. It consists of the dynamic formation of covalent isopeptide bonds between a family member of the Small Ubiquitin Like Modifiers (SUMOs) and the target proteins. Interestingly, it is a cellular mechanism implicated in several neurodegenerative pathologies and potentially it could become a new therapeutic target; however, there are very few pharmacological tools to modulate the SUMOylation process. In this study, we have designed and tested the activity of a novel small cell-permeable peptide, COV-1, in a neuroblastoma cell line that specifically prevents protein SUMOylation. COV-1 inhibits UBC9-protein target interaction and efficiently decreases global SUMO-1ylation. Moreover, it can perturb RanGAP-1 perinuclear localization by inducing the downregulation of UBC9. In parallel, we found that COV-1 causes an increase in the ubiquitin degradation system up to its engulfment while enhancing the autophagic flux. Surprisingly, COV-1 modifies protein aggregation, and specifically it mislocalizes TDP-43 within cells, inducing its aggregation and co-localization with SUMO-1. These data suggest that COV-1 could be taken into future consideration as an interesting pharmacological tool to study the cellular cascade effects of SUMOylation prevention.

1402 Impact of COVID-19 on Nasal Fracture Presentation and Epidemiology: A Retrospective Comparative Case-series Study

Aim

Nasal fractures (NF) are the most common ENT presentation and commonly managed in the clinic or A&E. With the recent COVID pandemic, this study aims to assess the difference in demographics, incidence and aetiology in NF since the start of the first lockdown (16/03/2020) as well as management of nasal fractures.

Method

Retrospectively, data collection on demographics, history and management over 5 years (2015-2020) for all patients presenting with symptoms of nasal fracture. Data was collected on password-protected Excel spreadsheet and subsequent statistical analysis performed using IBM SPSS Statistics.

Results

A total of 346 patients were identified of which 36 were diagnosed during the lockdown. Seventy-one percent were ≤40 years old and common aetiology recorded was assault (n = 85), sports (n = 85) and falls (n = 77). Mechanical fall was the common aetiology in older patients. Across gender, falls was the most common aetiology in females (37/94) and assault for males (72/246). Epistaxis (57%) and nasal congestion (31.8%) were most commonly reported symptoms. Before lockdown, Fifty-six percent of the cohort underwent manipulation of NF under local anaesthetic and no intervention needed in 39% while 58% underwent no intervention during the lockdown. No patients were readmitted in 30 days who were treated conservatively or with local anaesthetic during the lockdown.

Conclusions

This study showed that the most common cause of NF was sports and assault while during the lockdown, falls was the leading cause. More patients were managed conservatively during the lockdown with no 30-readmission showing that conservative management was as effective as management under local anaesthetic.

503 Clinical Frailty Score (CFS) Vs Antibiotics, Time to Surgery and Time to Computerised Tomography (CT) Scan in An Emergency Surgical Population

Introduction

Frail patients have increased mortality after surgery. However, it is not known if pre-operative process measures such as antibiotic administration, time to CT and time to surgery are influenced by patient frailty.

Method

The Emergency Laparotomy and Laparoscopy Scottish Audit (ELLSA) assessed outcome after emergency surgery across Scottish hospitals (November 2017 – October 2018). Frailty was measured using the 7-point Clinical Frailty Score (CFS). Outcome measures were antibiotic provision for sepsis, admission to CT time, admission to surgery time, CT request to performance time and CT request to surgery time.

Results

1302 patients (median age 63 years [IQR 49-74]; 49% male) with complete data were included. Median time from admission to CT and surgery increased between those with CFS 1 to 6/7 from 597 to 1724 minutes (p < 0.0001) and 1556 to 4120 minutes (p < 0.0001) respectively. Time from CT request to surgery also significantly increased with CFS (p < 0.042). There was no significant association between CFS and antibiotic administration or CT request to performance.

Conclusions

Frail patients have to wait longer for CT scan requests and surgery, but frailty was not associated with antibiotic administration or delays in CT request to performance time. Possible explanations include frailty-related challenges making correct diagnoses and optimal management plans.

Role of endoscopic ultrasound-guided fine-needle aspiration in the diagnosis of space occupying lesions of the pancreas

Introduction: Space occupying lesions (SOLs) of the pancreas are commonly encountered in day to day practice either as an incidental finding or during evaluation of symptomatic patients. The aim of the present study was to compare the final diagnosis at follow-up with diagnosis made at computed tomography (CT)/magnetic resonance imaging (MRI) and endoscopic ultrasound (EUS). Materials and Methods: Retrospective analysis of EUS data of 131 patients referred for tissue diagnosis of SOL in pancreas was done. The lesions were classified as malignant, benign, and nonneoplastic by both CT/MRI and endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) in conjunction with clinical presentation, biochemical parameters, and tumor markers. Follow-up cases with a final diagnosis alone were included for the comparative analysis. Statistical Analysis: Chi-square test, sensitivity, specificity, positive predictive value (PPV), and negative predictive values (NPV) for CT/MRI and EUS-FNA were computed against the follow-up data. Results: Of the 131, there were 78 males (59.5%). The median age of presentation was 48 years (range: 11–82 years. Follow-up information on the final diagnosis was available for 54 patients. Confirmed diagnosis at follow-up was malignant lesion in 18, benign in 13 and 23 with a nonneoplastic lesion. When EUS-FNA outcome was compared with the definitive diagnosis of the 54 patients, it had a higher sensitivity for malignant (66.7% vs. 61.1%) and nonneoplastic lesions (78.3% vs. 73.9%) and was similar to CT/MRI for benign lesions (76.9% for both). EUS-FNA had a higher specificity (87.8% vs. 80.5%) with a good PPV for benign lesions (66.7% vs. 55.6%). CT/MRI was less accurate than EUS-FNA in predicting benign (79.6% vs. 85.2%) and nonneoplastic lesions (79.6% vs. 81.5%) compared to malignant lesions wherein it was similar at 81.5%. The high NPV with a lower PPV for both EUS/FNA and CT/MRI suggests that follow-up definitive diagnosis was superior to both –. Conclusions: Endoscopic ultrasound-guided fine-needle aspiration had a higher specificity, but low sensitivity for the both neoplastic and nonneoplastic lesion of the pancreas compared to the world literature. The overall EUS-FNA yield was low when compared to the follow-up definitive diagnosis.

Autologous mononuclear cells from different sources are seen to improve wound healing in patients with haematological malignancies

INTRODUCTION

Immunosuppressive state due to haematological malignancies and chemotherapy may cause disruption to wound healing despite optimum conventional treatment and standard wound dressing. Non-healing wounds are predisposed to infection whereas chemotherapy dose reductions or interruptions are associated with poor survival.

BACKGROUND

Mononuclear cells contain progenitor cells including haematopoietic and mesenchymal stem cells, endothelial progenitor cells and fibroblasts which facilitate wound healing through cytokines, growth factor secretions, cell-cell interactions and provision of extracellular matrix scaffolding. Clinical applications of autologous mononuclear cells therapy in wound healing in non-malignant patients with critical limb ischaemia have been reported with remarkable outcome.

METHODS

We report three patients with haematological malignancies undergoing chemotherapy, who received autologous mononuclear cells implantation to treat non-healing wound after optimum conventional wound care. The sources of mononuclear cells (MNC) were from bone marrow (BM), peripheral blood (PB) and mobilised PB cells (mPB-MNC) using granulocyte colony stimulating factor (G-CSF). The cells were directly implanted into wound and below epidermis. Wound sizes and adverse effects from implantation were assessed at regular intervals.

RESULTS

All patients achieved wound healing within three months following autologous mononuclear cells implantation. No implantation adverse effects were observed.

CONCLUSIONS

Autologous mononuclear cells therapy is a feasible alternative to conventional wound care to promote complete healing in non-healing wounds compounded by morbid factors such as haematological malignancies, chemotherapy, diabetes mellitus (DM), infections and prolonged immobility.

Hybrid composite of nitrogen functionalized graphene–polyaniline electrode for high performance supercapacitor

A high performance supercapacitor was obtained with an electrode composed of a hybrid material of nitrogen-functionalized graphene with polyaniline.

Peripancreatic tuberculous lymphadenitis in an immunocompetent patient

Tuberculosis, an ancient disease continues to be a health care burden in Malaysia in the 21st century. Extrapulmonary tuberculosis is a less common presentation of tuberculosis and in particular peripancreatic tuberculous lymphadenitis is rarely seen. We report a case of a young immunocompetent boy presenting with a two month history of non productive chronic cough associated with loss of appetite and loss of weight. Investigations including CT Scan and Endoscopic ultrasound revealed multiple mediastinal lymphadenopathy and peripancreatic lymphadenopathy with central caseation necrosis. Histology of cervical lymph node was suggestive of tuberculosis and mycobacterium PCR was positive. The patient was subsequently treated with antituberculous therapy and had marked clinical improvement of his symptoms. This case outlines a rare presentation of a common disease and the application of newer investigative tools in making the diagnosis.

Mycophenolate mofetil therapy for refractory inflammatory bowel disease

BACKGROUND

Mycophenolate mofetil (MMF) is an immunomodulatory drug, and its use in inflammatory bowel disease has previously been reported. The aim of this study was to review the Leeds Colitis Clinic experience of the safety and efficacy of MMF in treating patients with refractory Crohn's disease (CD) and ulcerative colitis (UC). This is an extension of a previously published study from our center with a longer follow-up period and approximately twice the number of patients.

METHODS

A retrospective analysis was performed of the records of all patients treated with MMF for inflammatory bowel disease over a 5-year period.

RESULTS

Of 70 patients identified, 67 had previously been treated with azathioprine unsuccessfully. Seventeen of the 70 patients had been successfully maintained in remission with MMF for an average duration of 33 months. Treatment with MMF was discontinued for 53 patients, 17 because of side effects and 36 because they had not responded to the treatment.

CONCLUSIONS

In our series, 17 patients (24.3%) had a sustained steroid-free remission with MMF therapy. Nineteen patients (27%) experienced side effects, of which 17 (24.3% of the total group) had to discontinue therapy. An additional 36 (51.4%) required an escalation in medical therapy or surgery because of failure of the MMF therapy. MMF may have a role in the treatment of refractory inflammatory bowel disease, especially in patients who have previously failed standard therapies such as azathioprine.

Empyema of lung associated with Streptococcus milleri infection

Empyema of the lung is a very serious illness which must be detected quickly and treated aggressively. We report an unusual case of empyema of the lung associated with a boating accident while the patient was fishing in a sea loch off the west coast of Scotland.

Characterization of the binding of different conformational forms of plasminogen activator inhibitor-1 to vitronectin. Implications for the regulation of pericellular proteolysis

Plasminogen activator inhibitor type 1 (PAI-1), the primary physiologic inhibitor of plasminogen activation, is associated with the adhesive glycoprotein vitronectin (Vn) in plasma and the extracellular matrix. In this study we examined the binding of different conformational forms of PAI-1 to both native and urea-purified vitronectin using a solid-phase binding assay. These results demonstrate that active PAI-1 binds to urea-purified Vn with approximately 6-fold higher affinity than to native Vn. In contrast, inactive forms of PAI-1 (latent, elastase-cleaved, synthetic reactive center loop peptide-annealed, or complexed to plasminogen activators) display greatly reduced affinities for both forms of adsorbed Vn, with relative affinities reduced by more than 2 orders of magnitude. Structurally, these inactive conformations all differ from active PAI-1 by insertion of an additional strand into beta-sheet A, suggesting that it is the rearrangement of sheet A that results in reduced Vn affinity. This is supported by the observation that PAI-1 associated with beta-anhydrotrypsin, which does not undergo rearrangement of beta-sheet A, shows no such decrease in affinity, whereas PAI-1 complexed to beta-trypsin, which does undergo sheet A rearrangement, displays reduced affinity for Vn similar to PAI-1.plasminogen activator complexes. Together these data demonstrate that the interaction between PAI-1 and Vn depends on the conformational state of both proteins and suggest that the Vn binding site on PAI-1 is sensitive to structural changes associated with loss of inhibitory activity.

Serpin reactive center loop mobility is required for inhibitor function but not for enzyme recognition

One feature that distinguishes all of the inhibitory members of the serpin gene family is the presence of a small uncharged residue at the P14 position of the reactive center loop. In this report we examine the effects of mutations at this position, in the serpin, plasminogen activator inhibitor type 1 (PAI-1). Replacement of the native P14 Thr-333 residue by an Arg (Thr-333-->Arg) resulted in complete loss of inhibitory activity toward tissue-type plasminogen activator and urokinase-type plasminogen activator. Comparison of the binding of the mutant inhibitor and wild type PAI-1 (WTPAI-1) to anhydrotrypsin indicated that the initial interaction of the two inhibitors with proteases was identical. However, whereas WTPAI-1 forms SDS-stable complexes with both plasminogen activators, the mutant PAI-1 was efficiently cleaved as a substrate. Amino-terminal sequence analysis indicated that cleavage of the mutant PAI-1 occurred at its reactive center P1-P1' Arg-Met bond. Thermal denaturation studies of native and cleaved PAIs indicated that native Thr-333-->Arg mutant had a thermal stability identical to active WTPAI-1 and that both proteins became significantly more stable following cleavage by elastase (cleaved at the P4-P3 bond). Finally, the function of recombinant PAI-1 variants containing 15 of the possible 19 amino acid substitutions at P14 were analyzed. While residue size appeared to have little effect on inhibitory activity, the presence of either a positive or a negative charge at P14, converted PAI-1 to a substrate. Taken together, these results suggest that while insertion of the reactive center loop is not essential for protease binding, it is a necessary second step required for inhibitor function. The presence of a charged residue at P14 can retard this insertion, resulting in conversion of the serpin to a substrate.

Localization of vitronectin binding domain in plasminogen activator inhibitor-1

Plasminogen activator inhibitor type 1 (PAI-1) is the rapid physiologic inhibitor of tissue-type plasminogen activator and urokinase-type plasminogen activator (uPA). In plasma and the extracellular matrix, PAI-1 is associated with the adhesive glycoprotein vitronectin. In order to characterize the PAI-1 structural domain responsible for binding to vitronectin, the segment of the PAI-1 cDNA encoding amino acids 13-147 (nucleotides 248-650) was randomly mutagenized and subcloned into a bacterial expression vector containing the mature PAI-1 coding sequence. Recombinant PAI-1 mutants were expressed in Escherichia coli and bacterial lysates assayed in duplicate for uPA inhibitory activity and vitronectin binding. Of 190 clones screened, six consistently demonstrated decreased vitronectin binding relative to uPA inhibitory activity. DNA sequence analysis of four of these clones identified 10 unique missense mutations, all located between base pairs 298 and 641, with each clone containing between one and four substitutions. Each substitution was expressed independently by site-directed mutagenesis and again analyzed for uPA inhibitory activity and vitronectin binding. Five point mutations that selectively disrupt vitronectin binding were identified. All 5 residues are located on the exterior of the PAI-1 structure. These findings appear to define a complex binding surface that bridges alpha-helices C and E to beta-strand 1A and includes amino acids 55, 109, 110, 116, and 123. These results suggest that vitronectin binding may stabilize the active conformation of PAI-1 by restricting the movement of beta-sheet A and thereby preventing insertion of the reactive center loop.

Engineering plasminogen activator inhibitor 1 mutants with increased functional stability

Plasminogen activator inhibitor 1 (PAI-1), a member of the serine protease inhibitor (Serpin) superfamily, is the primary inhibitor of the plasminogen activators tPA and uPA. PAI-1 is produced in an active form but converts to an inactive or latent form with a half-life of approximately 1 h at pH 7.5, 37 degrees C. This study describes the construction, expression, and characterization of PAI-1 mutants with increased functional stability. Three mutations that disrupt an ion pair, present in latent PAI-1, between Arg-30 and Glu-350 (P4'), were introduced into recombinant PAI-1. All three mutant proteins maintained normal functional activity against both uPA and tPA. However, the half-life of each purified PAI-1 mutant was extended compared to the 1.1 h observed for wild-type PAI-1 (wtPAI-1) (1.2 h for Glu-350-->Arg, 2.0 h for Glu-350-->Pro, and 2.1 h for the Arg-30-->Glu mutation). An additional PAI-1 variant containing a second mutation designed to potentially reconstitute the ion pair (Arg-30-->Glu, Glu-350-->Arg) failed to restore the wild-type half-life. Circular dichroism spectra analysis indicated that the active and latent forms of wtPAI-1 and all four mutants contained similar secondary structural elements. Thermal stability determinations showed that latent wtPAI-1 was much more structurally stable than the active conformation. However, the latent form for all four mutants was significantly less stable than the corresponding wtPAI-1 conformer. This is the first report of PAI-1 mutants which have been specifically engineered to produce enhanced functional stability.