Gynecologic carcinosarcomas (GyCS) are rare but aggressive cancers with both epithelial and stromal malignant components. GyCS tumors often recur and are resistant to the standard therapeutic regime of carboplatin. As such, there is a critical need to identify novel therapeutics to treat these tumors. This project aims to characterize GyCS tumors and assess the preclinical activity of novel cell-based immunotherapies utilizing patient-derived xenograft (PDX) models. Primary GyCS tumor samples were collected from a patient, dissociated into single cells, and injected intraperitoneally into NSG mice (N=10). After the PDX model was established, the mice were harvested, and the material from these mice was cryopreserved for use in forthcoming experiments. Utilizing flow cytometry, we identified elevated expression of HER2, a tumor-associated antigen, and Natural Killer (NK) ligands CD155 and CD112 within our PDX model. After treating 8 PDX mice with carboplatin, significant tumor burden remained. However, the expression of HER2 and NK ligands was retained, indicating the vulnerability of GyCS tumors to NK cell-based immunotherapies. The tumor-killing efficacy of HER2 monoclonal antibody (mAb) and NK cell combination therapy was also tested in a cohort of 5 PDX mice. Mice treated with HER2-NK dual therapy survived significantly longer and had significantly reduced tumor burdens compared to the controls. We hope this data sheds light on GyCS pathophysiology and avenues for novel therapies for patients diagnosed with GyCS.

Retinitis pigmentosa (RP) is an incurable retinal degenerative disease that affects an estimated 1 in 4000 individuals globally. RP-associated mutations cause photoreceptor loss and reactive gliosis in Müller glia (MG). MG provide structural and metabolic support to photoreceptors in healthy and degenerating retinas, but prolonged gliosis produces cytotoxic glial scars. These scars harbor extracellular matrix proteins that inhibit neuroplasticity and promote further degeneration. This project aims to profile changes in cell surface and secreted proteomes of MG throughout RP in the retinal degeneration 10 (rd10) mouse model. We perform in situ cell-surface proteome extraction by extracellular labeling (iPEEL), a proximity labeling technique, on retinas from rd10pde6b/pde6b;Slc1a3-CreER;iPEEL–and rd10wt/wt controls–at 3 time points: postnatal day (P)16, P25, and P60, reflecting early, peak, and advanced stages of photoreceptor degeneration. These mice exhibit RP and allow for tamoxifen-induced, MG-specific proximity labeling of membrane proteins. I perform histological validations using immunohistochemistry to demonstrate that iPEEL can be applied to study the degenerating retina and visualize secreted protein localization. I will confirm successful enrichment of labeled proteins using western blot and profile changes in the cell surface proteome using label-free mass spectrometry. This study will allow us to identify cell surface proteins associated with glial scar formation, informing new therapeutic approaches.

Studying neurodegenerative diseases like Alzheimer’s disease presents significant obstacles. Unlike skin or blood cells, brain cells are difficult to extract due to the complexity of the procedures involved. Cell reprogramming can be used to convert one cell type into another to address this. However, indirect reprogramming first needs to transform cells into stem cells, which “resets” the cells and results in the loss of information such as age and smoking habits. Direct reprogramming can convert one differentiated cell type into another differentiated cell type without reverting the cell into a stem cell, and this is a more suitable method for studying age-related brain diseases. However, a significant limitation of direct reprogramming is its low efficiency, making the process costly and time-consuming. To investigate the multi-complexity of direct reprogramming, a transcription factor is fused with an ACD protein, testing the protein-DNA interaction when have multiple transcription factors and distinct functions. Function like chromatin remodeling, activation, and silencing is being studying. This project is finding a way to overcome the low efficiency of direct reprogramming and contribute to neurodegenerative disease studies.

Stem cell (SC) differentiation is critical for embryonic development and tissue homeostasis. Within the craniofacial skeleton, stem cells support ongoing bone repair and regeneration. Cranial sutures, which are fibrous joints that separate the flat bones protecting the brain, house SCs responsible for maintaining cranial bones throughout postnatal life. However, in a common congenital anomaly called craniosynostosis, cranial sutures prematurely fuse, leading to the loss of SC populations and thereby impeding proper skull growth. While SC populations within these cranial sutures have been extensively investigated in adults, their embryonic and early postnatal counterparts – stages of robust bone growth and the onset of craniosynostosis – remain poorly understood. Using the new SC marker Six2 to identify putative SCs at cranial sutures, I hypothesize that SCs are the primary method of bone growth at embryonic stages. To test this hypothesis, I treated Six2-CreERT;Ai14 mouse embryos with tamoxifen at gestational days (GD) 11-15 time points and harvested at GD18. I performed immunohistochemistry on cryosections and imaged for SP7+ osteoblasts and tdTomato+ lineage-traced cells using confocal microscopy. Qualitative analysis of these experiments revealed tdTomato+ cells within the suture and in osteoblasts that form neighboring bones. These findings suggest that Six2+ cells within the coronal suture differentiate into osteoblasts, supporting the role of embryonic cranial sutures as reservoirs for SCs that drive bone growth.

Neurodevelopmental and psychiatric disorders (NPDs) pose significant challenges to public health, and understanding the genetic basis of these conditions is crucial for developing effective interventions. Despite the previous research that has been conducted on NPDs, understanding the molecular mechanism that underlie these disorders, has proved to be a challenge within the field of neuroscience. Current research has identified a plethora of high-confidence risk genes associated with NPDs, but the consequences of mutations within these genes are not yet well understood. This knowledge gap is further exacerbated by the current reliance on rodent models, which may not properly capture the complex features of the human brain. Furthermore, there is a lack of knowledge regarding how numerous mutations that contribute to the development of NPDs may interact to produce the complicated phenotypes that are commonly observed in these disorders. To address these gaps in knowledge, this research project focuses on studying the differences observed in high-confidence NPD risk genes using induced pluripotent-derived brain organoids. Multiple cell lines with different mutations will be used in parallel, which will ultimately provide comparison groups for the analysis. We will cultivate organoids and conduct quality control analyses using qPCR and IHC techniques to evaluate organoid formation and structure. Ultimately, this project seeks to define the functions of genes associated with neurological disease risk in neural development, asking