Whole organ engineering has emerged as a promising alternative avenue to fill the gap of donor organ shortage in organ transplantation. Recent breakthroughs in the decellularization of solid organs and repopulation with desired cell populations have generated neo-organ constructs with promising functional outcomes. The realization of this goal requires engineering advancement in the perfusion-based bioreactors to (i) efficiently deliver decellularization agents, followed by (ii) its reconstruction with relevant cell types and (iii) maintenance of viability and function of the repopulated organ. In this study, we report the development and assembly of a perfusion bioreactor with the potential to enable regenerative reconstruction of pancreas. The assembled bioreactor is versatile to efficiently decellularize multiple organs, as demonstrated by complete decellularization of pancreas, liver and heart in the same set-up. Further, the same system is amenable to support organ repopulation with diverse cell types. Using our in-house bioreactor system, we demonstrate pancreas repopulation with both immortalized MIN-6 beta cells and differentiating human pluripotent stem cells. Importantly, we show the significant advantage of perfusion culture over static culture in enhancing cell engraftment, viability and phenotypic maintenance of the repopulated pancreas. In addition, this study is a significant step forward for whole organ engineering as it will facilitate cost-effective and easy assembly of perfusion bioreactors to enable rapid advancement in regenerative organ reconstruction.
The investigation of molecular mechanisms underlying transcriptional regulation, particularly in embryonic stem cells, has received increasing attention and involves the systematic identification of target genes and the analysis of promoter co-occupancy. High-throughput approaches based on chromatin immunoprecipitation (ChIP) have been widely used for this purpose. However, these approaches remain time-consuming, expensive, labor-intensive, involve multiple steps, and require complex statistical analysis. Advances in this field will greatly benefit from the development and use of simple, fast, sensitive and straightforward ChIP assay and analysis methodologies. We initially developed a simplified, basic ChIP protocol that combines simplicity, speed and sensitivity. ChIP analysis by real-time PCR was compared to analysis by densitometry with the ImageJ software. This protocol allowed the rapid identification of known target genes for SOX2, NANOG, OCT3/4, SOX17, KLF4, RUNX2, OLIG2, SMAD2/3, BMI-1, and c-MYC in a human embryonic stem cell line. We then developed a novel Sequential ChIP protocol to investigate in vivo promoter co-occupancy, which is basically characterized by the absence of antibody-antigen disruption during the assay. It combines centrifugation of agarose beads and magnetic separation. Using this Sequential ChIP protocol we found that c-MYC associates with the SOX2/NANOG/OCT3/4 complex and identified a novel RUNX2/BMI-1/SMAD2/3 complex in BG01V cells. These two TF complexes associate with two distinct sets of target genes. The RUNX2/BMI-1/SMAD2/3 complex is associated predominantly with genes not expressed in undifferentiated BG01V cells, consistent with the reported role of those TFs as transcriptional repressors. These simplified basic ChIP and novel Sequential ChIP protocols were successfully tested with a variety of antibodies with human embryonic stem cells, generated a number of novel observations for future studies and might be useful for high-throughput ChIP-based assays.
Type 1 diabetes affects more than a million people in the United States and many more across the world. While pharmaceutical interventions and insulin supplementation are the most commonplace treatment of diabetes, these are not essentially cures and can potentially lead to long-term complications. Transplantation of insulin-producing Islets of Langerhans from donor pancreas has been established as a promising alternative to diabetes therapy. While successful islet transplantation has the potential of providing a cure, the primary hurdles to be overcome for it to be clinically viable are the scarcity of donor islets and immune rejection of transplanted islets. Recent advances in stem cell culture and differentiation techniques have established stem cells as a likely source of transplantable islets. Different stem cell sources have been induced toward pancreatic differentiation using specific chemical perturbations along with use of specific substrates. An approach to overcoming the second hurdle of immune rejection of transplantable islets is to encapsulate the islets in specific biomaterials. In this review, we discuss the extensive use of various substrates for pancreatic differentiation of different stem cell sources, along with different biomaterial designs used for islet transplantation.
The Biotechnology and Life Sciences Advising (BALSA) Group is a graduate studentand post-doctoral fellow-led strategic consulting firm dedicated to supporting economic growth and development in St. Louis, Missouri. BALSA has been recognized by St. Louis civic leaders as a valuable player in the St. Louis entrepreneurial community and has demonstrated that graduate students and post-doctoral fellows – without formal training – can provide professional business strategy support to start-ups, growing companies, and large corporations. The BALSA Group has inspired the establishment of similar groups around the United States, including Fourth River Solutions (4RS) at the University of Pittsburgh, in forming sustainable organizations that support their local entrepreneurial communities. Key to the success of new organizations are university Technology Transfer Offices, which can become recurring clients and serve as training grounds to build the core competencies of student-run consulting groups. This article highlights the success of The BALSA Group and 4RS in developing a novel addition to the Ph.D./post-doctoral fellow training paradigm, focusing on collaborations with Technology Transfer Offices, and describes a model for creating similar ventures at other universities. Keywords: Academic commercialization, Fourth River Solutions, BALSA, Technology transfer, Trainee-led consulting.
