Biology subjects

Conway, H.

Publications and source records attributed to Conway, H..

3 recordsLinked to original sources

bioRxiv2024

Engineered Bxb1 variants improve integrase activity and fidelity

Many current genome editing technologies rely on the action of large serine integrases (LSIs) to insert gene-sized DNA sequences into the genome. Bxb1 is the most commonly used LSI for therapeutic efforts, including PASTE, PASSIGE and I-PGI. While Bxb1 demonstrated good activity in vitro in cycling cells, the activity in non-dividing hepatocytes was significantly less efficient. Further, wild-type Bxb1 is known to have detectable off-target activity at cryptic genomic sites, which presents a potential safety risk for therapeutic development. To address these issues, we developed Bxb1 variants that demonstrate increased specificity and potency in vitro and have engineered stabilized Bxb1 variants that increase in vivo activity over 25-fold enabling targeted integration at therapeutically relevant levels.

biochemistry↗

bioRxiv2024

Altered B Cell Metabolic Pathways Characterize Type 1 Diabetes Progression

Type 1 diabetes (T1D) results in immune-mediated destruction of insulin-producing beta cells in the pancreas. B cells have been identified as critical, pathogenic antigen presenting cells and their specificity drives disease progression. At the same time, immunosuppressive, IL-10- producing regulatory B cells (Bregs) have been shown to play protective roles in mouse models of several autoimmune diseases, including rheumatoid arthritis and multiple sclerosis. In these models, microenvironmental stimuli induce regulatory B cell differentiation. Specifically, signaling through hypoxia-inducible factor 1 (HIF-1) drives a glycolytic flux that facilitates Breg expansion. While Breg frequencies are decreased in individuals with T1D compared to healthy controls, the role B regs play, how microenvironmental stimuli influence their differentiation, and whether this is altered in T1D progression, which is characterized by progressive, systemic hyperglycemia, are less clear. Here we examine the relationship between B cell differentiation, cellular metabolism, and HIF-1 to reveal that in a mouse model of autoimmune diabetes, B cells have distinct metabolic characteristics that change with disease progression. Further, response to hypoxia in autoimmune B cells is distinct from the response by non-autoimmune, control B cells. Together, these data suggest that dysregulated HIF signaling may skew the B cell repertoire toward inflammatory, rather than regulatory B cell subsets to drive T1D development. Consequently, HIF-1 activation to expand regulatory B cell populations may be a viable option for immune modulation.

immunology↗

bioRxiv2019

Reciprocal regulation of pancreatic ductal adenocarcinoma growth and molecular subtype by HNF4α and SIX1/4

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with a five-year survival of less than 5%. Transcriptomic analysis has identified two clinically relevant molecular subtypes of PDAC: Classical and Basal-like. The Classical subtype is characterized by a more favorable prognosis and better response to chemotherapy than the Basal-like subtype. The Classical subtype also expresses higher levels of lineage specifiers that regulate endodermal differentiation, including the nuclear receptor HNF4. Using in vitro and in vivo PDAC models, we show that HNF4 restrains tumor growth and drives tumor cells toward an epithelial identity. Gene expression analysis from murine models and human tumors shows that HNF4 activates expression of genes associated with the Classical subtype. Although HNF4 loss is not sufficient for complete conversion to the Basal-like subtype gene expression profile, HNF4 directly represses SIX4 and SIX1, mesodermal lineage specifiers expressed in the Basal-like subtype. Finally, HNF4-negative PDAC cells rely on expression of SIX4 and SIX1 for proliferation in vitro and in vivo. Overall, our data show that HNF4 regulates the growth and molecular subtype of PDAC by multiple mechanisms, including activation of the Classical gene expression program and repression of SIX4 and SIX1, which may represent novel dependencies of the Basal-like subtype.

cancer biology↗