LMP student seminars: 28 January
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
Kamalben Prajapati
- Title: Identification of High-Risk Asymptomatic Carotid Artery Stenosis Patients Using Multiomics and Molecular Aging Clocks
- Supervisor: Dr. Kathryn Howe
Abbie Lo
- Title: Developing hPSC-Derived Liver Organoids with Hepatocytes and Endothelial Cells
- Supervisor: Dr. Shinichiro Ogawa
Abstracts
Kamalben Prajapati: Identification of High-Risk Asymptomatic Carotid Artery Stenosis Patients Using Multiomics and Molecular Aging Clocks
Introduction: Carotid Artery Stenosis (CAS) is a cause of ischemic stroke. CAS management is based on symptoms (stroke) and the degree of stenosis. Asymptomatic CAS patients remain at risk for an unpredictable ischemic stroke event. We hypothesize that multiomics can uncover high-risk asymptomatic CAS patients who warrant aggressive management.
Methods: The study was approved by the institutional ethics board. The DNA methylome of peripheral blood mononuclear cells (PBMCs) was used to calculate epigenetic age by two methods: DunedinPACE (pacing of aging) and IntrinClock (accounting for cell-type heterogeneity in PBMCs). Deep plasma proteomics was performed (SEER Inc.). Analysis of differentially methylated regions (DMRs) and enriched proteins (DEPs), followed by pathway enrichment, was performed.
Results: While DunedinPACE was higher in CAS patients (n=173) compared to healthy controls (n=28), IntrinClock age was greater than chronological age in symptomatic CAS (n=27) patients (P<0.05). Pathway analysis of symptomatic (n=27) vs asymptomatic CAS (n=146) DMRs revealed senescence, MAPK, and Ras signalling enrichment, while DEPs revealed immune response pathways (q<0.05). To interrogate CAS at an early stage, DEP analysis was performed in non-severe CAS (<70% stenosis) patients. K-means clustering of non-severe CAS patients using DEPs in symptomatic non-severe CAS patients revealed a “high-risk” asymptomatic population that clustered with symptomatic CAS patients (cluster 1), separate from asymptomatic patients (cluster 2) that may be “low-risk”. Pathway analysis of cluster 1 vs 2 DEPs revealed enrichment of complement activation and angiogenesis pathways (q<0.05).
Conclusion: Multiomics can identify high-risk CAS patients. Future work aims to use these insights in developing a multimodal tool to risk-stratify asymptomatic CAS patients.
Abbie Lo: Investigating Neuroinflammation and Immune Activation in Neurodegenerative Proteinopathies using Imaging Mass Cytometry
Human pluripotent stem cell (hPSC)–derived hepatocytes remain functionally immature relative to adult hepatocytes, largely due to the absence of non-parenchymal cell interactions that shape the hepatic microenvironment. To address this limitation, we engineered co-cultured hPSC-derived liver organoids composed of hepatocytes and venous endothelial progenitors (END) to enhance functional capacities beyond what is achieved in hepatocyte-only systems.
Partially matured Zone 1–like hepatocytes (ALB⁺ AFPlow) and CD31⁺ CXCR4⁻ CD32⁻ END were independently generated and co-embedded as single-cell suspensions into free-floating Matrigel droplets, followed by eight days of culture in a hepatocyte-supportive medium.
Co-culture with Z1 hepatocytes significantly increased maintenance of endothelial identity, yielding a higher CD31⁺ END population (83.95% ± 3.46) compared with monoculture (54.73% ± 6.70). A CD32b⁺ subset (9.73% ± 1.10) also emerged in co-culture, suggesting hepatocyte-driven acquisition of LSEC-like features. Hepatocytes retained lineage stability, with comparable ALB⁺ frequencies in monoculture (97.54% ± 0.96) and co-culture (96.46% ± 0.88). A small AFP⁺ subset remains present in co-culture (3.65% ± 0.80) but not in monoculture, while the predominant ALB⁺ AFP⁻ phenotype was preserved overall, indicating that END interactions do not substantially impair hepatocyte maturation.
Future work will incorporate hPSC-derived hepatic stellate cells to establish a tri-lineage organoid system and to determine whether multicellular co-culture activates hepatocyte gene programs or functions not achieved in monoculture.
This study establishes a more physiologically relevant multicellular hPSC-derived liver organoid platform with potential applications in regenerative medicine, cell therapy, disease modeling, and drug screening.
Contact
No need to register.
Contact lmp.grad@utoronto.ca with any questions.