HIF-1α activation in myeloid cells accelerates dextran sodium sulfate-induced colitis progression in mice.

Inflammatory bowel disease (IBD) is a chronic inflammatory disease, in which the intestinal epithelium loses its barrier function. Given the existence of the oxygen gradient in the intestinal epithelium and that inflammation further contributes to the tissue hypoxia, we investigated the role of hypoxia-inducible factor (HIF), a transcription factor activated under hypoxic conditions in myeloid cells, in the progression of IBD. To do this, we utilized myeloid-specific knockout (KO) mice targeting HIF pathways, created by a Cre-loxP system with human MRP8 (hMRP8), an intracellular calcium-binding protein, as the myeloid promoter. By feeding 5% dextran sodium sulfate (DSS) to hMRP8 von Hippel Lindau (Vhl) KO mice, in which HIF-1α and HIF-2α are constitutively activated in myeloid cells, we found that these mice were highly susceptible to DSS-induced colitis, demonstrating greater body weight loss, increased mortality, faster onset of rectal bleeding, shortened colon length, and increased CD11b- or Gr-1-positive myeloid cells in the colon compared with wild-type (WT) mice. These parameters were restored to, if not better than, the WT levels when we examined hMRP8 Hif-1a KO mice upon 5% DSS feeding. hMRP8 Hif-2a KO mice, on the other hand, exhibited a similar degree of DSS-induced colitis to that of WT mice. Lastly, when DSS was given together with azoxymethane to induce tumorigenesis in the colon, we found that hMRP8 Hif-1a KO mice exhibited comparable levels of colorectal tumors to those of WT mice, indicating that HIF-1α in myeloid cells is dispensable for tumorigenesis. Collectively, our results suggest that HIF-1α activation in myeloid cells critically regulates IBD progression.

Hyaluronate-Death Receptor 5 Antibody Conjugates for Targeted Treatment of Liver Metastasis.

The liver is the most frequent site of metastasis with a 5-year survival rate of only 20-40%. In this work, hyaluronate (HA)-death receptor 5 antibody (DR5 Ab) conjugate was synthesized as a dual targeting therapeutic agent to treat liver metastasis. Dual targeting was achieved by DR5 Ab, a humanized agonistic monoclonal antibody binding to DR5 frequently overexpressed in many kinds of cancer cells, and by HA, a natural polysaccharide binding to HA receptors highly expressed in both the liver and cancer cells. Thiol end-modified HA was site-specifically conjugated to N-glycan on Fc region of oxidized DR5 Ab using a heterobifunctional linker of 3-(2-pyridyldithio)propionyl hydrazide (PDPH). The successful synthesis of HA-DR5 Ab conjugate was confirmed by (1)H NMR, purpald assay, dynamic light scattering (DLS), and high-performance liquid chromatography (HPLC). In vitro analysis of HA-DR5 Ab conjugate revealed that the conjugation of HA to DR5 Ab did not affect the binding affinity and anticancer efficacy of DR5 Ab. Remarkably, according to in vivo bioimaging study, HA-DR5 Ab conjugate appeared to be highly accumulated in the liver and dramatically effective in inhibiting the tumor growth in liver metastasis model mice.