Radiation exposure is acutely damaging to the hematopoietic system and can lead to death due to bone marrow (BM) failure. Our laboratory is working to develop an off-the-shelf source of cord-blood derived endothelial progenitor cells (EPCs) to be used as a cellular therapy for the mitigation of acute radiation-induced hematopoietic injury. Previously, we reported infusion of EPCs promotes hematopoietic reconstitution of lethally irradiated mice in part by the release of the brain-derived neurotrophic factor (BDNF). Brain-derived neurotrophic factor (BDNF) is a nerve growth factor that has been studied and used experimentally to combat neurodegenerative diseases. BDNF is used to promote neural regeneration through activation of the tyrosine kinase receptor (TrkB). Here, we reveal that the BDNF signaling promotes hematopoietic regeneration following a sublethal dose of 5 Gy total body irradiation (TBI) in C57BL/6 mice. To evaluate the therapeutic potential of BDNF-TrkB pathway activation, we treated mice systemically starting at 24 hours post-irradiation with either recombinant BDNF (IV, 0.5 mg/kg) or the small molecule TrkB agonist 7,8-dihydroxyflavone (7,8-DHF; IP, 1 mg/kg). Mice were dosed three times weekly through endpoint. BDNF or 7,8-DHF improved recovery of BM vascular integrity and function. Concurrent with improvement in vascular recovery, both BDNF and 7,8-DHF accelerated recovery of mature myeloid and lymphocyte cells. These data suggest pharmacologic activation of the BDNF pathway with BDNF or 7,8-DHF may be an effective medical countermeasure for hematologic toxicity in victims of acute radiation exposure.

Antibiotics (ABX) have been used as treatments for many years, but it is now known that these drugs wipe out large populations of microflora and cause shifts in a person’s overall microbiota (gut bacteria) composition. Given that the microbiome can affect a person’s overall intestinal homeostasis and metabolism, understanding the effects of these sudden shifts has become a popular area of research. In this study we used broad-spectrum antibiotics (Ampicillin, Neomycin, and Vancomycin) and the drug Metronidazole to perturb the peritoneal cavity. The aim of this study is to determine whether antibiotic treatment perturbs peritoneal cavity immunobiology. It was hypothesized that there would be a shift in the B1 cell population after (antibiotic) treatment leading to an alteration in their quantity. Given that this population of B cells are primary producers of natural antibodies, it could be inferred that a sudden change in microflora composition could alter their quantity. Antibiotic administration was given through intraperitoneal injection and peritoneal samples were obtained through peritoneal wash. Cell counts were taken on a hemocytometer under a microscope to determine whether there was an observable difference between both control and ABX treatment groups. Flow Cytometry was used to compare the immune cell populations in control and antibiotic treated mice by using fluorescently labeled antibody cocktails that bind to specific immune cell markers for differentiation. Given that evidence now suggests that gut microbes may also influence response to cancer therapeutics, it becomes increasingly important to understand the role that they play (Helmink et al., 2019).

Ferredoxin reductase (FdxR) is a mitochondrial membrane-associated flavoprotein required for various cellular processes such as steroidogenesis, heme A formation, and biosynthesis of iron-sulfur clusters (ISC). Studies have shown that mutations in FdxR are associated with mitochondriopathy, optic atrophy, and increased reactive oxygen species (ROS) in humans and mice. FDXR protein contains a mitochondria localization signal, a nuclear localization sequence, an NADP-binding domain, and two FAD-binding domains that are used for electron transport from NADPH to ferredoxin. FDXR is present as eight different isoforms due to alternative splicing. Isoform one is most abundant in the cell, followed by isoform four and isoform seven. Interestingly, FdxR isoforms four, seven and eight have an altered mitochondria localization signal, while others contain extra amino acids that may affect their binding to NADP and FAD. These data suggest that FDXR isoforms may have similar and distinct functions, which warrants further investigation of its expression and localization in different organelles. The aim of our research is to generate expression plasmids of FDXR isoforms with mutations in the nuclear localization signal and the mitochondria localization signal using molecular cloning and to analyze their expression in cancer cell lines. This study will help to understand the biology and the pathways of FdxR.

Bloom’s syndrome (BS) is an inherited autosomal recessive disorder that causes an increased risk of developing multiple early onset cancers. Proportional small size and a photosensitive, facial skin rash are features exhibited by persons with Bloom’s syndrome (BS). BS is caused by loss-of-function mutations in the BLM gene. BS cells exhibited increased chromosome breakage, hyper-recombination, and excessive mutation. BLM protein is modified by SUMO at lysine residue 331 and expression of a GFP-tagged BLM with a lysine to arginine mutation at this residue are complemented for the hyper-recombination phenotype but instead exhibit a striking replication defect and spontaneous phosphorylation of H2AX. This present study aims to determine whether or not these phenotypic effects are present in cells that carry the endogenous SUMO-acceptor site mutation K331R. This question is important as the result will show the extent to which the mutant phenotype is caused by over-expression of the mutant gene project, and potentially patients with SUMO acceptor-site mutations may have a phenotype different from BS. This study will also provide information on how these phenotypes and mutations may influence increased cancer risk.