Person:

Schwartz, Dana

Patients with short bowel syndrome lack sufficient functional intestine to sustain themselves with enteral intake alone. Transplantable vascularized bioengineered intestine could restore nutrient absorption. Here we report the engineering of humanized intestinal grafts by repopulating decellularized rat intestinal matrix with human induced pluripotent stem cell-derived intestinal epithelium and human endothelium. After 28 days of in vitro culture, hiPSC-derived progenitor cells differentiate into a monolayer of polarized intestinal epithelium. Human endothelial cells seeded via native vasculature restore perfusability. Ex vivo isolated perfusion testing confirms transfer of glucose and medium-chain fatty acids from lumen to venous effluent. Four weeks after transplantation to RNU rats, grafts show survival and maturation of regenerated epithelium. Systemic venous sampling and positron emission tomography confirm uptake of glucose and fatty acids in vivo. Bioengineering intestine on vascularized native scaffolds could bridge the gap between cell/tissue-scale regeneration and whole organ-scale technology needed to treat intestinal failure patients.

The Mycobacterium tuberculosis genome encodes 11 serine/threonine protein kinases (STPKs) that are structurally related to eukaryotic kinases. To gain insight into the role of Ser/Thr phosphorylation in this major global pathogen, we used a phosphoproteomic approach to carry out an extensive analysis of protein phosphorylation in M. tuberculosis. We identified more than 500 phosphorylation events in 301 proteins that are involved in a broad range of functions. Bioinformatic analysis of quantitative in vitro kinase assays on peptides containing a subset of these phosphorylation sites revealed a dominant motif shared by six of the M. tuberculosis STPKs. Kinase assays on a second set of peptides incorporating targeted substitutions surrounding the phosphoacceptor validated this motif and identified additional residues preferred by individual kinases. Our data provide insight into processes regulated by STPKs in M. tuberculosis and create a resource for understanding how specific phosphorylation events modulate protein activity. The results further provide the potential to predict likely cognate STPKs for newly identified phosphoproteins.