Recent developments in the field of inorganic chemistry have shown boron clusters, atomically precise cages made up of boron-boron bonds with the capacity for functionalization, as efficient delivery systems for a diverse range of cargos. For clusters with halogenated vertices, this carrier ability has been linked to their potential chaotropic nature. My project aimed to examine the potential of the Spokoyny group’s novel and non-commercially available boron cluster to deliver metal-based fluorescent dyes and therapeutics to human cells. My work has focused on characterizing the cytotoxic profile of each cluster in HeLa cells using a dimethylthiazol diphenyltetrazolium (MTT) assay. Following this, we used confocal microscopy to determine which of the non-toxic clusters are able to increase the uptake of metal-fluorescent compounds. From these results, we observed that iteratively adding hydroxyl groups to the clusters provided less cytotoxic activity with roughly the same ability to deliver cargo of interest. To further understand this effect, we ran classic salting-in experiments to quantify the chaotropic nature of each cluster by studying their ability to solubilize the riboflavin. From these studies, we found that clusters with smaller halogen atoms (chlorine) attached to the boron cage, adding hydroxyl groups improved their chaotropic nature, while the opposite was true for larger halogens (bromine). Following this work, we plan to use isothermal titration calorimetry (ITC) experiments with liposomes to determine the strength of interaction between the clusters and payloads for use in therapeutic purposes.

The parasite responsible for African trypanosomiasis, Trypanosoma brucei, depends on its flagellum for motility, transmission, and pathogenesis. Doublet microtubules in the flagellum contain recently discovered microtubule inner proteins (MIPs), including a MIP subset that comprises the inner junction (IJ) of the doublet. We hypothesize that MIPs are important for flagellum stability and motility in T. brucei and that lineage-specific MIPs contribute to the parasite’s unique motility. Knockdown of one of the five known IJ MIPs in T. brucei, FAP106, showed that FAP106 is critical for assembly of other IJ MIPs and novel T. brucei-specific MIP candidates (MCs). We knocked down individual MIPs and conducted tandem mass tag (TMT) proteomics to identify MIPs lost in response to each knockdown and conducted functional assays to test for phenotypic defects. One MC we studied, MC15, is required for motility, but not for the assembly of other MIP structures. High-resolution cryo-electron microscopy and localization studies found that MC15 is not located within the doublet and it may have cell-cycle dependency. Further, knockdowns of the IJ MIPs PACRG-A and PACRG-B were found to independently result in shortened flagellum length and loss of different axonemal proteins in TMT proteomics, in contrast to prior studies.

Osteoarthritis (OA) is a common joint disease, characterized by articular cartilage (AC) loss and osteophyte formation. No current therapy or disease-modifying drug exists. Healthy bone and cartilage formation relies on the balance between the transforming growth factor beta (TGF-beta) and the bone morphogenic protein (BMP) signaling pathways. The major role of the TGF-beta type I receptor (ALK5) in growth plate cartilage is to suppress the BMP pathway because ALK5 loss leads to greater pSMAD1/5 mediated BMP signaling via greater ALK1/ACTRIIB complex formation. Our studies indicate similar mechanisms in articular cartilage. Post-traumatic OA (PTOA) development can be prevented by inhibiting ALK1/2, using a BMP- Kinase inhibitor (BMP-KI) to block kinase function or a ligand trap protein (ALK1-Fc) to block ligand binding. Employing micro-CT analysis, histological analysis, and behavioral testing, mice induced with PTOA and treated with ALK1-Fc and ALK1-KI displayed significantly less osteophyte volume and articular cartilage morphology of the osteoarthritic joint is improved, these findings suggest that both ALK1-KI and the ALK1-Fc are promising therapeutic agents for treating OA.