Targeting transglutaminase 2 mediated exostosin glycosyltransferase 1 signaling in liver cancer stem cells with acyclic retinoid.

Transglutaminase 2 (TG2) is a multifunctional protein that promotes or suppresses tumorigenesis, depending on intracellular location and conformational structure. Acyclic retinoid (ACR) is an orally administered vitamin A derivative that prevents hepatocellular carcinoma (HCC) recurrence by targeting liver cancer stem cells (CSCs). In this study, we examined the subcellular location-dependent effects of ACR on TG2 activity at a structural level and characterized the functional role of TG2 and its downstream molecular mechanism in the selective depletion of liver CSCs. A binding assay with high-performance magnetic nanobeads and structural dynamic analysis with native gel electrophoresis and size-exclusion chromatography-coupled multi-angle light scattering or small-angle X-ray scattering showed that ACR binds directly to TG2, induces oligomer formation of TG2, and inhibits the transamidase activity of cytoplasmic TG2 in HCC cells. The loss-of-function of TG2 suppressed the expression of stemness-related genes, spheroid proliferation and selectively induced cell death in an EpCAM+ liver CSC subpopulation in HCC cells. Proteome analysis revealed that TG2 inhibition suppressed the gene and protein expression of exostosin glycosyltransferase 1 (EXT1) and heparan sulfate biosynthesis in HCC cells. In contrast, high levels of ACR increased intracellular Ca2+ concentrations along with an increase in apoptotic cells, which probably contributed to the enhanced transamidase activity of nuclear TG2. This study demonstrates that ACR could act as a novel TG2 inhibitor; TG2-mediated EXT1 signaling is a promising therapeutic target in the prevention of HCC by disrupting liver CSCs.

Hepatic stellate cell stearoyl co-A desaturase activates leukotriene B4 receptor 2 - ß-catenin cascade to promote liver tumorigenesis.

Hepatocellular carcinoma (HCC) is the 3rd most deadly malignancy. Activated hepatic stellate cells (aHSC) give rise to cancer-associated fibroblasts in HCC and are considered a potential therapeutic target. Here we report that selective ablation of stearoyl CoA desaturase-2 (Scd2) in aHSC globally suppresses nuclear CTNNB1 and YAP1 in tumors and tumor microenvironment and prevents liver tumorigenesis in male mice. Tumor suppression is associated with reduced leukotriene B4 receptor 2 (LTB4R2) and its high affinity oxylipin ligand, 12-hydroxyheptadecatrienoic acid (12-HHTrE). Genetic or pharmacological inhibition of LTB4R2 recapitulates CTNNB1 and YAP1 inactivation and tumor suppression in culture and in vivo. Single cell RNA sequencing identifies a subset of tumor-associated aHSC expressing Cyp1b1 but no other 12-HHTrE biosynthetic genes. aHSC release 12-HHTrE in a manner dependent on SCD and CYP1B1 and their conditioned medium reproduces the LTB4R2-mediated tumor-promoting effects of 12-HHTrE in HCC cells. CYP1B1-expressing aHSC are detected in proximity of LTB4R2-positive HCC cells and the growth of patient HCC organoids is blunted by LTB4R2 antagonism or knockdown. Collectively, our findings suggest aHSC-initiated 12-HHTrE-LTB4R2-CTNNB1-YAP1 pathway as a potential HCC therapeutic target.

A case of giant primary splenic hydatid cyst: Case report.

Introduction: Primary splenic hydatidosis is a rare zoonotic disease, common in grazing regions of the world. Primary splenic hydatid cyst is rare and accounts for <2% of patients. Splenectomy is advocated in case of giant hydatid cyst locating in central and hilum area; however, spleen salvaging operations are done in superficial cyst, cysts localized to one pole of the spleen or cysts that are unresectable due to extensive adhesions and in children. Presentation of case: We present a case of 29-year male patient from rural areas presented with the complain of left hypochondriac pain and tenderness along with the history of farming and cattle raising. There was no other significant history. Clinical findings and investigations: Physical examination showed mildly distended abdomen, mild tenderness over left hypochondrium. Routine laboratory investigations were sent. Ultrasound and CT scan of the abdomen showed giant splenic cyst measuring approx. 15 × 14 × 11 cm along with daughter cysts. Postoperatively, cyst was sent for histopathological examination. Intervention and outcome: Preoperatively, vaccinations against Pneumococcus, Hemophilus influenzae and Meningococcus along with Albendazole (15 mg/kg/day) was given 2 weeks before the planned operation. Total splenectomy was performed and diagnosis was confirmed by histopathological examination. Albendazole was continued for 2 more weeks. Patient remains asymptomatic thereafter and regularly followed up in OPD basis. Relevance and impact: Presence of isolated splenic cyst should raise suspicion for primary splenic hydatid cyst in endemic areas. Splenectomy versus spleen salvaging options should be analyzed and performed as per the indications. Splenic hydatid cyst is one of the rare clinical findings and there is very much high chance that it goes undiagnosed during the clinical practice. So, the main motive behind writing this article is to shed knowledge on basic approach to this splenic finding.

Burden and Risk Factors of Diabetic Retinopathy Among Diabetic Patients Attending a Multispecialty Tertiary Eye Hospital in Nepal.

INTRODUCTION: As the number of people with diabetes mellitus is increasing because of urbanization and change in dietary habits and sedentary lifestyle, the number of diabetic retinopathy is also expected to increase in future. [1] [sa2] We aimed to find out the prevalence of diabetic retinopathy and associated risk factors among diabetic patients in the tertiary eye hospital. MATERIALS AND METHODS: This is the observational cross-sectional study enrolling 420 diabetic patients visiting the multispecialty tertiary eye hospital between March 2020 and February 2021. Anthropometry measurement, laboratory risk profiles and blood pressure were recorded Results: The prevalence of any diabetic retinopathy, proliferative diabetic retinopathy, and diabetic macular edema were 30.96 %, 6.19 %, and 5.95 % respectively. The duration of DM (p=0.001), hypertension (p=0.04), high SBP (p=0.023), abdominal obesity (p=0.015), high LDL(p=0.011) cholesterol, low HDL cholesterol(p=0.012), and creatinine (p=0.001) were associated with DR in our study. CONCLUSION: A holistic approach should target to control the modifiable risk factors like blood sugar, blood pressure, lipid profile, kidney function, and obesity to prevent DR. Anthropometric assessment of waist to height and waist circumference should be included in the holistic health promotion strategy in Nepal as BMI may not be risk factors for DR in Nepalese people.

Treatment Strategies in Acute Post-operative Endophthalmitis after Cataract Surgery at a Tertiary Eye Hospital in Nepal: A 5-year Retrospective Review.

INTRODUCTION: Despite best possible preventive measures, acute postoperative endophthalmitis (POE) is still the most devastating, sight-threatening complication after intraocular surgery and the most feared complication by treating surgeons. MATERIALS AND METHODS: It is a retrospective study of 22 eyes diagnosed as acute POE following cataract surgery in the last 5 years (2015-2019), aimed to evaluate the treatment strategies used in its management. Main outcome measures evaluated were rates of repeat intravitreal injection, adjunctive therapeutic regimens, pars plana vitrectomy (PPV) and visual outcome. RESULTS: Twenty one eyes (95.45%) received repeated intravitreal injection. Adjuvant intravitreal steroid was used in 12 eyes (54.54%), oral steroid in 16 eyes (72.72%) and oral antibiotic in 8 eyes (36.36%). PPV was done in 8 eyes (34.78%) and all 8 eyes that underwent PPV had a vision of Hand Movement (HM) close to face. 7 eyes (87.5%) had early PPV within 1 week of diagnosis. The median best corrected visual acuity (BCVA) improved from 1.00 logMar to 0.8 logMar following treatment at 3 months follow up (p= 0.117). CONCLUSION: Repeat intravitreal injections were commonly employed. Early PPV was performed more commonly regardless of the visual acuity at the time of diagnosis of acute POE.

Use of Intravitreal Bevacizumab Injection among Patients Undergoing Surgical Retinal Interventions at Tertiary Eye Hospital: A Descriptive Cross-sectional Study.

INTRODUCTION: Intravitreal Bevacizumab injection has now become a routine procedure for retina specialists throughout the world. Easy availability of this monoclonal antibody molecule even in Nepal has brought a revolution in the management of various retinal diseases. This study aims to find out the prevalence of the use of intravitreal Bevacizumab for retinal diseases at the tertiary eye hospital. METHODS: This descriptive cross-sectional study was carried out in the retina department at a tertiary care hospital from January 2017 to December 2019 after obtaining ethical clearance from Nepal Health Research Council (Ref: 125/2020P). The sample size was calculated and the study enrolled all patients who received intravitreal Bevacizumab for retinal diseases using convenience sampling technique. Data were analyzed using Statistical Package for Social Science Version 21. Point estimate at 95% Confidence Interval was calculated, along with frequency and percentage for binary data. RESULTS: Out of 959 total surgical retinal interventions done 296 (30.86%) at 95% Confidence Interval (27.93-33.78) patients received intravitreal Bevacizumab. Out of total intravitreal Bevacizumab injections, 143 (36.7%) injections were given to retinal vein occlusions patients, 127 (32.6%) injections were given to diabetic retinopathy patients and 66 (17%) injections was given to age-related macular degeneration patients. Males 176 (59.5%) outnumbered the females 120 (40.5%) in receiving intravitreal Bevacizumab. Mean baseline Logarithm of the Minimal Angle of Resolution visual acuity, 1.1, improved to, 0.75, after 3 months of intravitreal Bevacizumab. CONCLUSIONS: Intravitreal Bevacizumab was one of the commonest retinal interventions used. Retinal vein occlusion, diabetic retinopathy, and age-related macular degeneration were the commonest retinal diseases needing intravitreal Bevacizumab.

Fungus-derived hydroxyl radicals kill hepatic cells by enhancing nuclear transglutaminase.

We previously reported the importance of induced nuclear transglutaminase (TG) 2 activity, which results in hepatic cell death, in ethanol-induced liver injury. Here, we show that co-incubation of either human hepatic cells or mouse primary hepatocytes derived from wild-type but not TG2-/- mice with pathogenic fungi Candida albicans and C. glabrata, but not baker's yeast Saccharomyces cerevisiae, induced cell death in host cells by enhancing cellular, particularly nuclear, TG activity. Further pharmacological and genetic approaches demonstrated that this phenomenon was mediated partly by the production of reactive oxygen species (ROS) such as hydroxyl radicals, as detected by a fluorescent probe and electron spin resonance. A ROS scavenger, N-acetyl cysteine, blocked enhanced TG activity primarily in the nuclei and inhibited cell death. In contrast, deletion of C. glabrata nox-1, which encodes a ROS-generating enzyme, resulted in a strain that failed to induce the same phenomena. A similar induction of hepatic ROS and TG activities was observed in C. albicans-infected mice. An antioxidant corn peptide fraction inhibited these phenomena in hepatic cells. These results address the impact of ROS-generating pathogens in inducing nuclear TG2-related liver injuries, which provides novel therapeutic targets for preventing and curing alcoholic liver disease.

Phenosafranin inhibits nuclear localization of transglutaminase 2 without affecting its transamidase activity.

Transglutaminase 2 (TG2) localizes to the nucleus and induces apoptosis through a crosslinking inactivation of Sp1 in JHH-7 cells treated with acyclic retinoid. We screened an inhibitor suppressing transamidase activity in the nucleus without affecting transamidase activity itself. Phenosafranin was found to inhibit nuclear localization of EGFP-tagged TG2 and dose-dependently reduce nuclear transamidase activity without affecting the activity in a tube. We concluded that phenosafranin was a novel TG2 inhibitor capable of suppressing its nuclear localization.