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1.  The Myeloid Immune Signature of Enterotoxigenic Bacteroides Fragilis-Induced Murine Colon Tumorigenesis 
Mucosal immunology  2016;10.1038/mi.2016.53.
Enterotoxigenic Bacteroides fragilis (ETBF), a human commensal and candidate pathogen in colorectal cancer (CRC), is a potent initiator of IL-17-dependent colon tumorigenesis in MinApc+/-mice. We examined the role of IL-17 and ETBF on the differentiation of myeloid cells into myeloid-derived suppressor cells (MDSC) and tumor-associated macrophages (TAM), which are known to promote tumorigenesis. The myeloid compartment associated with ETBF-induced colon tumorigenesis in Min mice was defined using flow cytometry and gene expression profiling. Cell sorted immature myeloid cells were functionally assayed for inhibition of T cell proliferation and iNOS expression in order to delineate MDSC populations. A comparison of ETBF infection to that of other oncogenic bacteria (Fusobacterium nucleatum or pks+ E. coli) revealed a specific, ETBF-associated colonic immune infiltrate. ETBF-triggered colon tumorigenesis is associated with an IL-17-driven myeloid signature characterized by subversion of steady-state myelopoiesis in favor of the generation of protumoral monocytic (MO)-MDSCs. Combined action of the Bacteroides fragilis enterotoxin BFT and IL-17 on colonic epithelial cells promoted the differentiation of MO-MDSCs, which selectively upregulated Arg1 and Nos2, produced NO and suppressed T cell proliferation. Evidence of a pathogenic inflammatory signature in humans colonized with ETBF may allow for the identification of populations at risk for developing colon cancer.
doi:10.1038/mi.2016.53
PMCID: PMC5159334  PMID: 27301879
Enterotoxigenic Bacteroides fragilis; myeloid derived suppressor cells; tumor microenvironment; tumor-promoting inflammation; Fusobacterium nucleatum; pks+E. coli
2.  Metabolism links bacterial biofilms and colon carcinogenesis 
Cell metabolism  2015;21(6):891-897.
SUMMARY
Bacterial biofilms in the colon alter the host tissue microenvironment. A role for biofilms in colon cancer metabolism has been suggested but to date has not been evaluated. Using metabolomics, we investigated the metabolic influence that microbial biofilms have on colon tissues and the related occurrence of cancer. Patient-matched colon cancers and histologically normal tissues, with or without biofilms, were examined. We show the upregulation of polyamine metabolites in tissues from cancer hosts with significant enhancement of N1, N12-diacetylspermine in both biofilm positive cancer and normal tissues. Antibiotic treatment, which cleared biofilms, decreased N1, N12-diacetylspermine levels to those seen in biofilm negative tissues, indicating that host cancer and bacterial biofilm structures contribute to the polyamine metabolite pool. These results show that colonic mucosal biofilms alter the cancer metabolome, to produce a regulator of cellular proliferation and colon cancer growth potentially affecting cancer development and progression.
doi:10.1016/j.cmet.2015.04.011
PMCID: PMC4456201  PMID: 25959674
3.  Bacterial oncogenesis in the colon 
Future microbiology  2013;8(4):445-460.
The human colon plays host to a diverse and metabolically complex community of microorganisms. While the colonic microbiome has been suggested to contribute to the development of colorectal cancer (CRC), a definitive link has not been made. The role in which the colon microflora could contribute to the initiation and/or progression of CRC is explored in this review. Potential mechanisms of bacterial oncogenesis are presented, along with lines of evidence derived from animal models of microbially induced CRC. Particular focus is given to the oncogenic capabilities of enterotoxigenic Bacteroides fragilis. Recent progress in defining the microbiome of CRC in the human population is evaluated, and the future challenges of linking specific etiologic agents to CRC are emphasized.
doi:10.2217/fmb.13.17
PMCID: PMC4052711  PMID: 23534358
bacterial toxin; chronic inflammation; colonic microbiome; colorectal cancer; genotoxins; oncogenesis
4.  Peripheral Hyperstimulation Alters Site of Disease Onset and Course in SOD1 Rats 
Neurobiology of disease  2010;39(3):252-264.
In amyotrophic lateral sclerosis (ALS), the exogenous temporal triggers that result in initial motor neuron death are not understood. Overactivation and consequent accelerated loss of vulnerable motor neurons is one theory of disease initiation. The vulnerability of motor neurons in response to chronic peripheral nerve hyperstimulation was tested in the SOD1G93A rat model of ALS. A novel in vivo technique for peripheral phrenic nerve stimulation was developed via intra-diaphragm muscle electrode implantation at the phrenic motor endpoint. Chronic bilateral phrenic nerve hyperstimulation in SOD1G93A rats accelerated disease progression, including shortened lifespan, hastened motor neuron loss and increased denervation at diaphragm neuromuscular junctions. Hyperstimulation also resulted in focal decline in adjacent forelimb function. These results show that peripheral phrenic nerve hyperstimulation accelerates cell death of vulnerable spinal motor neurons, modifies both temporal and anatomical onset of disease, and leads to involvement of disease in adjacent anatomical regions in this ALS model.
doi:10.1016/j.nbd.2010.03.021
PMCID: PMC2910141  PMID: 20381620
motor neuron; neurodegeneration; ALS; amyotrophic lateral sclerosis; SOD1; phrenic nerve; diaphragm; diaphragm pacing; diaphragm stimulation; respiratory; disease onset; environment
5.  Focal Transplantation-based Astrocyte Replacement is Neuroprotective in a Model of Motor Neuron Disease 
Nature neuroscience  2008;11(11):1294-1301.
Cellular abnormalities in amyotrophic lateral sclerosis (ALS) are not limited to motor neurons. Astrocyte dysfunction occurs in human ALS and SOD1G93A animal models. Therefore, the value of focal enrichment of normal astrocytes was investigated using transplantation of lineage-restricted astrocyte precursors, Glial-Restricted Precursors (GRPs). GRPs were transplanted around cervical spinal cord respiratory motor neuron pools, the principal cells responsible for death in this neurodegenerative disease. GRPs survived in diseased tissue, differentiated efficiently into astrocytes, and reduced microgliosis in SOD1G93A rat cervical spinal cord. GRPs extended survival and disease duration, attenuated motor neuron loss, and slowed declines in fore-limb motor and respiratory physiological function. Neuroprotection was mediated in part by the primary astrocyte glutamate transporter, GLT1. These findings demonstrate the feasibility and efficacy of transplantation-based astrocyte replacement, and show that targeted multi-segmental cell delivery to cervical spinal cord is a promising therapeutic strategy for slowing focal motor neuron loss associated with ALS.
doi:10.1038/nn.2210
PMCID: PMC2656686  PMID: 18931666
stem cell; grafting; transplantation; motor neuron; neurodegeneration; replacement; neuroprotection; non-cell autonomous; astroglia; astrocyte; neural precursor cell; progenitor; lineage-restricted precursor; glial precursor; ALS; amyotrophic lateral sclerosis; SOD1

Results 1-5 (5)