LMP student seminars: 5 November

Each week during term time, MSc and PhD candidates in the Department of Laboratory Medicine and Pathobiology present their research.

Anyone is welcome. No need to register.

Location: Medical Sciences Building, rooms 4171 or 4279, see below.

As part of the core research curriculum, students taking LMP1001/2/3: Graduate Seminars in Laboratory Medicine and Pathobiology will present their projects. Please see abstracts below.

Group 3: Cardiovascular, Physiology and Metabolism

Location: MSB 4171

Ness Little

• Title: Adeno-associated virus mediated expression of Bcl-xL attenuates apoptosis in Fuchs Endothelial Corneal Dystrophy
• Supervisor: Dr. Stephan Ong Tone

Group 5: Infectious Diseases, Inflammation and Immunology

Location: MSB 4279

Nan Chen

• Title: Colon Rora+ ILCs regulate sex dimorphism in insulin resistance during diet-induced obesity
• Supervisor: Dr. Daniel Winer

Abstracts

Ness Little: Adeno-associated virus mediated expression of Bcl-xL attenuates apoptosis in Fuchs Endothelial Corneal Dystrophy

Purpose: Fuchs Endothelial Corneal Dystrophy (FECD) is characterized by corneal endothelial cell loss and the formation of corneal guttae. Currently, there is a shortage of donor corneas and new strategies are needed to reduce the need for transplantation. While adeno-associated viruses (AAVs) have the capacity to deliver anti-apoptotic genes to human corneal endothelial cells (HCECs), this has not been fully explored as a therapeutic strategy for FECD.

Methods: 17 scAAV2 serotypes were screened for transduction efficiency by green fluorescent protein (GFP) expression in normal HCECs. The four scAAV2 serotypes with the highest transduction were tested in ex vivo specimens from healthy cadaveric donors. scAAV2/2 and scAAV2/5 were tested in two FECD HCEC lines and FECD ex vivo specimens. Apoptosis was induced with etoposide in FECD HCECs transduced with ssAAV2/5-Bcl-xL (AAV2/5-CAG-eGFP-P2A-BCLXL), control ssAAV2/5 (AAV2/5-CAG-eGFP), or no AAV.

Results: scAAV2/2, 2/5, 2/6, 2/DJ showed the highest transduction efficiencies in normal HCECs (63.81%±4.64, 37.92%±14.18, 33.61%±14.13, 37.64%±11.77). scAAV2/5 transduction remained high in healthy cadaveric donor tissues (48.03%±8.61), FECD HCEC lines (FECD-SV-54F-73=33.22%±13.50, FECD-SVF6-61M=41.97%±10.27), and FECD ex vivo specimens (76.75%±21.71). ssAAV2/5-Bcl-xL transduced FECD HCECs well (53.36%±24.20) and significantly attenuated etoposide-induced apoptosis (23.96%±8.88) when compared to both those transduced with ssAAV2/5 (70.42%±4.96; p=0.038) and non-transduced HCECs (71.68%±0.69; p=0.018).

Conclusions: scAAV2/5 transduced HCECs and ex vivo tissues with high efficiency. ssAAV2/5-Bcl-xL transduction attenuated etoposide-induced apoptosis in FECD HCECs. Future studies may explore using AAVs to deliver other anti-apoptotic genes, target the Bcl-xL pathways as a treatment for FECD, or to attenuate apoptosis related to corneal donor tissue storage.

Nan Chen: Colon Rora+ ILCs regulate sex dimorphism in insulin resistance during diet-induced obesity

Obesity and its associated metabolic abnormalities, including insulin resistance (IR), are the leading risk factors for type 2 diabetes. Multiple factors contribute to IR, but chronic inflammation of metabolic tissues, including visceral adipose tissue (VAT), liver, and muscle, is a major contributor. Recent evidence suggests that, during obesity, the intestinal immune cells, which are gatekeepers maintaining the gut barrier and intestinal homeostasis, exhibit a pro-inflammatory shift leading to worsened intestinal permeability, endotoxemia, and systemic inflammation in metabolic tissues like VAT, thereby exacerbating IR. Interestingly, males are more likely to develop obesity, IR, and other metabolic syndromes than females. While sex hormones are known to regulate multiple metabolic and immune pathways, whether they contribute to the sex-specific alteration of the intestinal immune system and metabolic outcomes of obesity-induced IR is unknown. Here, we propose to unravel sexually dimorphic phenotypes of IR by studying the gut immune system. Using our newly generated single cell atlas and custom integrative bioinformatics, we will investigate how diet-induced obesity alters the colonic lamina propria in male and female mice. We demonstrate that HFD-fed male mice show increased accumulation of a potentially pathogenic B cells coupled to decreased abundances of other major cells, particularly ILC subsets. We have identified critical master regulator factors, including ROR (Retinoid-related orphan receptors) factors and fibroblast populations potentially directing these changes. Thus, the overall long-term goal of this work is two-fold: (i) to identify how biological sex impacts the gut immune system during IR, and (ii) determine how changes in the gut immune system drives obesity-related metabolic disease in males and females.

Contact

No need to register.

Contact lmp.grad@utoronto.ca with any questions.