Differential Contribution of Pancreatic Fibroblast Subsets to the Pancreatic Cancer Stroma.

BACKGROUND & AIMS: Although the healthy pancreas consists mostly of epithelial cells, pancreatic cancer and the precursor lesions known as pancreatic intraepithelial neoplasia, are characterized by an extensive accumulation of fibroinflammatory stroma that includes a substantial and heterogeneous fibroblast population. The cellular origin of fibroblasts within the stroma has not been determined. Here, we show that the Gli1 and Hoxb6 markers label distinct fibroblast populations in the healthy mouse pancreas. We then set out to determine whether these distinct fibroblast populations expanded during carcinogenesis. METHODS: We developed genetically engineered models using a dual-recombinase approach that allowed us to induce pancreatic cancer formation through codon-optimized Flp recombinase-driven epithelial recombination of Kirsten rat sarcoma viral oncogene homolog while labeling Gli1+ or Hoxb6+ fibroblasts in an inducible manner. By using these models, we lineage-traced these 2 fibroblast populations during the process of carcinogenesis. RESULTS: Although in the healthy pancreas Gli1+ fibroblasts and Hoxb6+ fibroblasts are present in similar numbers, they contribute differently to the stroma in carcinogenesis. Namely, Gli1+ fibroblasts expand dramatically, whereas Hoxb6+ cells do not. CONCLUSIONS: Fibroblasts present in the healthy pancreas expand during carcinogenesis, but with a different prevalence for different subtypes. Here, we compared Gli1+ and Hoxb6+ fibroblasts and found only Gli1+ expanded to contribute to the stroma during pancreatic carcinogenesis.

An assay for clogging the ciliary pore complex distinguishes mechanisms of cytosolic and membrane protein entry.

As a cellular organelle, the cilium contains a unique protein composition. Entry of both membrane and cytosolic components is tightly regulated by gating mechanisms at the cilium base; however, the mechanistic details of ciliary gating are largely unknown. We previously proposed that entry of cytosolic components is regulated by mechanisms similar to those of nuclear transport and is dependent on nucleoporins (NUPs), which comprise a ciliary pore complex (CPC). To investigate ciliary gating mechanisms, we developed a system to clog the pore by inhibiting NUP function via forced dimerization. We targeted NUP62, a component of the central channel of the nuclear pore complex (NPC), for forced dimerization by tagging it with the homodimerizing Fv domain. As proof of principle, we show that forced dimerization of NUP62-Fv attenuated (1) active transport of BSA into the nuclear compartment and (2) the kinesin-2 motor KIF17 into the ciliary compartment. Using the pore-clogging technique, we find that forced dimerization of NUP62 attenuated the gated entry of cytosolic proteins but did not affect entry of membrane proteins or diffusional entry of small cytosolic proteins. We propose a model in which active transport of cytosolic proteins into both nuclear and ciliary compartments requires functional NUPs of the central pore, whereas lateral entry of membrane proteins utilizes a different mechanism that is likely specific to each organelle's limiting membrane.

Outcomes in surgical treatment of "idiopathic-like" scoliosis associated with syringomyelia.

Patients with "idiopathic-like" spinal deformities associated with syringomyelia were retrospectively reviewed. Ten patients had surgical stabilization of their curvatures with at least a 2-year follow-up, and an additional five patients were evaluated for deformity pattern with <2 years of follow-up. Paralytic curve patterns, scoliosis associated with spina bifida, congenital scoliosis, or other associated syndromes were discarded. All 10 patients with surgery who were followed for an average of 46 months lost 10 degrees correction above, through, or below the instrumented segments. A total of 50% lost correction through the instrumented segments. Anterior fusion stabilized the instrumented portion of the spine better than posterior instrumentation alone. Eighty percent of the 15 patients had thoracic kyphosis >40 degrees. Only one patient was lordoscoliotic. Syringomyelia deformities tend to be kyphoscoliotic in 80% of cases and behave more like paralytic curvatures postoperatively. MRI is recommended for apparent idiopathic scoliotic curvatures that are kyphoscoliotic and not lordoscoliotic.

Spine behavior caudal to instrumentation in King II and IV curves.

This retrospective review of children surgically treated for King Type II or IV curvature of the spine required a minimum lumbar Cobb angle of 40 degrees and a minimum lumbar inclination (the angle formed between a line through the spinous processes of the three most caudal lumbar vertebrae and a line perpendicular to the floor) of 10 degrees. Twenty children had combined anterior thoracolumbar and posterior instrumentations whereas 20 had only posterior instrumentation. Children who had combined surgery had significantly better corrections of their lumbar Cobb angles. They had a mean correction of 43.3 degrees compared with 26.7 degrees in children with posterior instrumentation only. These superior corrections of the lumbar Cobb angles did not result in significantly better improvements in the lumbar inclinations. Patients who had the combined procedures had a mean improvement of 10.1 degrees, whereas patients who had posterior instrumentation only had a mean improvement of 8.0 degrees in lumbar inclination. Instead of having superior corrections of the lumbar inclinations, the combined surgeries resulted in a significant worsening of the angle between the end plates of the last instrumented vertebra and the next most caudal end plate. In patients who had combined surgery this angle averaged 8.4 degrees, whereas in patients who had posterior instrumentation only this angle averaged 4.1 degrees.